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"A manager in the minds of doctors" : a comparison of new modes of control in European hospitals
(2013)
Background: Hospital governance increasingly combines management and professional self-governance. This article maps the new emergent modes of control in a comparative perspective and aims to better understand the relationship between medicine and management as hybrid and context-dependent. Theoretically, we critically review approaches into the managerialism-professionalism relationship; methodologically, we expand cross-country comparison towards the meso-level of organisations; and empirically, the focus is on processes and actors in a range of European hospitals.
Methods: The research is explorative and was carried out as part of the FP7 COST action IS0903 Medicine and Management, Working Group 2. Comprising seven European countries, the focus is on doctors and public hospitals. We use a comparative case study design that primarily draws on expert information and document analysis as well as other secondary sources.
Results: The findings reveal that managerial control is not simply an external force but increasingly integrated in medical professionalism. These processes of change are relevant in all countries but shaped by organisational settings, and therefore create different patterns of control: (1) ‘integrated’ control with high levels of coordination and coherent patterns for cost and quality controls; (2) ‘partly integrated’ control with diversity of coordination on hospital and department level and between cost and quality controls; and (3) ‘fragmented’ control with limited coordination and gaps between quality control more strongly dominated by medicine, and cost control by management.
Conclusions: Our comparison highlights how organisations matter and brings the crucial relevance of ‘coordination’ of medicine and management across the levels (hospital/department) and the substance (cost/quality-safety) of control into perspective. Consequently, coordination may serve as a taxonomy of emergent modes of control, thus bringing new directions for cost-efficient and quality-effective hospital governance into perspective.
Je besser Forscher es verstehen, defekte Gene zu reparieren oder beliebige Körperzellen zu reprogrammieren, desto gefahrloser wird die Gen- und Stammzell-Therapie für Patienten, die an heute noch unheilbaren Krankheiten leiden. Gleichzeitig zeichnet sich damit die Möglichkeit ab, in ferner Zukunft vielleicht das Genom kommender Generationen zu verändern oder Menschen zu klonieren. Der Internist Prof. Hubert Serve und die Politikwissenschaftlerin Dr. Anja Karnein wagen im Gespräch mit den beiden Redakteurinnen des Wissenschaftsmagazins »Forschung Frankfurt« Dr. Anne Hardy und Ulrike Jaspers einen Ausblick jenseits aller aktuellen Debatten. Sie diskutieren aber auch über die Themen, die Patienten wie Wissenschaftler zurzeit unmittelbar berühren.
"PULS." - Ein Blog als Online-Magazin für Medizinstudierende der Goethe-Universität Frankfurt
(2013)
Im Herbst 2009 forderten Studierende im Rahmen landesweiter Proteste auch am Fachbereich Medizin/Zahnmedizin der Goethe-Universität Frankfurt mehr Transparenz und Kommunikation zu Angelegenheiten ihres Studiums. Einen innovativen Lösungsansatz, um diesen Forderungen nachzukommen, bietet eines der Web 2.0 Werkzeuge: ein auf einer Blog-Software basierendes Online-Magazin für Studierende und andere Mitglieder des Fachbereichs.
Das öffentlich zugängliche Online-Magazin "PULS." (https://newsmagazin.puls.med.uni-frankfurt.de/wp/) wird mit einer freien Blog-Software (wordpress Version 3.1.3.) realisiert und von einer Online-Redakteurin konzipiert und geschrieben. Die Beiträge entstehen nach eigenen Recherchen sowie aus Anregungen und Gesprächen mit verschiedenen Personengruppen des Fachbereichs. Die datenschutzkonforme Auswertung der Zugriffe erfolgt über eine open-source Webanalyse-Software (Piwik). Zusätzlich werden jährlich mit dem Online-Umfrage-Tool Survey Monkey die Nutzer anonym befragt.
"PULS." ist seit dem 14.02.2010 ununterbrochen online und hat seitdem 806 Beiträge (Stand: 27.11.2012) publiziert und wird von ca. 2400 Besuchern monatlich gelesen. Das Themenspektrum ist zentriert auf die Anliegen der Frankfurter Medizin- und Zahnmedizinstudierenden. Die enge Zusammenarbeit mit verschiedenen Gruppierungen des Fachbereichs – Dekanat, Studierende und Lehrende – garantiert darüber hinaus ein fachbereichs-relevantes Themenspektrum. Das Online-Magazin begleitet komplexe Projekte und Entscheidungen mit Hintergrundinformationen und kommuniziert sie verständlich. Eine jährliche Nutzer-Evaluierung zeigt eine wachsende Leserzahl und eine sehr hohe Zustimmung für das Online-Magazin, seine Inhalte und seinen Stil. Das Web 2.0-Medium "Blog" und seine web-typische Sprache entsprechen dem Medienverhalten der Zielgruppe, d.h. den Studierenden des Fachbereichs Medizin.
"PULS." hat sich als ein geeignetes und strategisches Instrument erwiesen, um größere Transparenz, mehr Kommunikation und letztendlich eine stärkere Identifikation der Studierenden mit ihrem Fachbereich voranzutreiben.
"PULS." – a blog-based online-magazine for students of medicine of the Goethe University Frankfurt
(2013)
In the context of nationwide protests 2009 also students of the faculty of medicine/dentistry at Goethe-University in Frankfurt demanded more transparency and communication. To satisfy these demands, a web 2.0-tool offered an innovative solution: A blog-based online-magazine for students and other faculty-members. The online-magazine "PULS." is realized with the share-ware blog-software (wordpress version 3.1.3) and is conceived and written by an online-journalist. "PULS." is available from https://newsmagazin.puls.med.uni-frankfurt.de/wp/. The articles are generated from own investigations and from ideas of different groups of the faculty– deanship, students and lecturers. A user-analysis is conducted with the open-source software Piwik and considers the data security. Additionally, every year an anonymous online-user-survey (Survey Monkey) is conducted. "PULS." is continuously online since 14.02.2010 and has published 806 articles (state: 27.11.2012) and has about 2400 readers monthly. The content focuses on the needs of Frankfurt medical students. The close cooperation with different groups of the faculty - deanship, students and lecturers - furthermore guarantees themes relevant to the academic faculty. "PULS." flanks complex projects and decisions with background-information and communicates them understandable. The user-evaluation shows a growing number of readers and a high acceptance for the online-magazine, its themes and its style. The web 2.0-tool "Blog" and the web-specific language comply with media habits of the main target group, the students of the faculty medicine/dentistry. Thus, "PULS." has proven as a suitable and strategic instrument. It pushes towards a higher transparency, more communication and a stronger identification of the students with their faculty.
Background and Aims: The Roadmap concept is a therapeutic framework in chronic hepatitis B for the intensification of nucleoside analogue monotherapy based on early virologic response. The efficacy and safety of this approach applied to telbivudine treatment has not been investigated.
Methods: A multinational, phase IV, single-arm open-label study (ClinicalTrials.gov ID NCT00651209) was undertaken in HBeAg-positive, nucleoside-naive adult patients with chronic hepatitis B. Patients received telbivudine (600 mg once-daily) for 24 weeks, after which those with undetectable serum HBV DNA (<300 copies/mL) continued to receive telbivudine alone while those with detectable DNA received telbivudine plus tenofovir (300 mg once-daily). Outcomes were assessed at Week 52.
Results: 105 patients commenced telbivudine monotherapy, of whom 100 were included in the efficacy analysis. Fifty-five (55%) had undetectable HBV DNA at Week 24 and continued telbivudine monotherapy; 45 (45%) received tenofovir intensification. At Week 52, the overall proportion of undetectable HBV DNA was 93% (93/100) by last-observation-carried-forward analysis (100% monotherapy group, 84% intensification group) and no virologic breakthroughs had occurred. ALT normalization occurred in 77% (87% monotherapy, 64% intensification), HBeAg clearance in 43% (65% monotherapy, 16% intensification), and HBeAg seroconversion in 39% (62% monotherapy, 11% intensification). Six patients had HBsAg clearance. Myalgia was more common in the monotherapy group (19% versus 7%). No decrease in the mean glomerular filtration rate occurred in either treatment group at Week 52.
Conclusions: Telbivudine therapy with tenofovir intensification at Week 24, where indicated by the Roadmap strategy, appears effective and well tolerated for the treatment of chronic hepatitis B.
Trial Registration: ClinicalTrials.gov NCT00651209
Background: One of the most popular and versatile model of murine melanoma is by inoculating B16 cells in the syngeneic C57BL6J mouse strain. A characterization of different B16 modified cell sub-lines will be of real practical interest. For this aim, modern analytical tools like surface enhanced Raman spectroscopy/scattering (SERS) and MTT were employed to characterize both chemical composition and proliferation behavior of the selected cells.
Methods: High quality SERS signal was recorded from each of the four types of B16 cell sub-lines: B164A5, B16GMCSF, B16FLT3, B16F10, in order to observe the differences between a parent cell line (B164A5) and other derived B16 cell sub-lines. Cells were incubated with silver nanoparticles of 50–100 nm diameter and the nanoparticles uptake inside the cells cytoplasm was proved by transmission electron microscopy (TEM) investigations. In order to characterize proliferation, growth curves of the four B16 cell lines, using different cell numbers and FCS concentration were obtained employing the MTT proliferation assay. For correlations doubling time were calculated.
Results: SERS bands allowed the identification inside the cells of the main bio-molecular components such as: proteins, nucleic acids, and lipids. An "on and off" SERS effect was constantly present, which may be explained in terms of the employed laser power, as well as the possible different orientations of the adsorbed species in the cells in respect to the Ag nanoparticles. MTT results showed that among the four tested cell sub-lines B16 F10 is the most proliferative and B164A5 has the lower growth capacity. Regarding B16FLT3 cells and B16GMCSF cells, they present proliferation ability in between with slight slower potency for B16GMCSF cells.
Conclusion: Molecular fingerprint and proliferation behavior of four B16 melanoma cell sub-lines were elucidated by associating SERS investigations with MTT proliferation assay.
Yeast cells can be killed upon expression of pro-apoptotic mammalian proteins. We have established a functional yeast survival screen that was used to isolate novel human anti-apoptotic genes overexpressed in treatment-resistant tumors. The screening of three different cDNA libraries prepared from metastatic melanoma, glioblastomas and leukemic blasts allowed for the identification of many yeast cell death-repressing cDNAs, including 28% of genes that are already known to inhibit apoptosis, 35% of genes upregulated in at least one tumor entity and 16% of genes described as both anti-apoptotic in function and upregulated in tumors. These results confirm the great potential of this screening tool to identify novel anti-apoptotic and tumor-relevant molecules. Three of the isolated candidate genes were further analyzed regarding their anti-apoptotic function in cell culture and their potential as a therapeutic target for molecular therapy. PAICS, an enzyme required for de novo purine biosynthesis, the long non-coding RNA MALAT1 and the MAST2 kinase are overexpressed in certain tumor entities and capable of suppressing apoptosis in human cells. Using a subcutaneous xenograft mouse model, we also demonstrated that glioblastoma tumor growth requires MAST2 expression. An additional advantage of the yeast survival screen is its universal applicability. By using various inducible pro-apoptotic killer proteins and screening the appropriate cDNA library prepared from normal or pathologic tissue of interest, the survival screen can be used to identify apoptosis inhibitors in many different systems.
Suitable and reproducible experimental models of translational research in reconstructive surgery that allow in-vivo investigation of diverse molecular and cellular mechanisms are still limited. To this end we created a novel murine model of acute hindlimb ischemia-reperfusion to mimic a microsurgical free flap procedure. Thirty-six C57BL6 mice (n = 6/group) were assigned to one control and five experimental groups (subject to 6, 12, 96, 120 hours and 14 days of reperfusion, respectively) following 4 hours of complete hindlimb ischemia. Ischemia and reperfusion were monitored using Laser-Doppler Flowmetry. Hindlimb tissue components (skin and muscle) were investigated using histopathology, quantitative immunohistochemistry and immunofluorescence. Despite massive initial tissue damage induced by ischemia-reperfusion injury, the structure of the skin component was restored after 96 hours. During the same time, muscle cells were replaced by young myotubes. In addition, initial neuromuscular dysfunction, edema and swelling resolved by day 4. After two weeks, no functional or neuromuscular deficits were detectable. Furthermore, upregulation of VEGF and tissue infiltration with CD34-positive stem cells led to new capillary formation, which peaked with significantly higher values after two weeks. These data indicate that our model is suitable to investigate cellular and molecular tissue alterations from ischemia-reperfusion such as occur during free flap procedures.
A rare cause of recurrent melena was identified by capsule endoscopy: arteriovenous malformation
(2013)
Small bowel endoscopy is indicated for patients with an unidentified bleeding site in esophagogastroduodenoscopy and ileocolonoscopy and symptoms of intestinal blood loss or unexplained anemia. In approximately two-thirds of these cases, capsule endoscopy (CE) detects a lesion within the small bowel that explains the patient's symptoms.
The case of an 80-year-old female patient with recurrent melena and anemia is presented here by the authors. Endoscopy of the upper gastrointestinal tract as well as ileocolonoscopy did not show any pathological findings. CE revealed an area with abnormal mucosa in the middle third of the small bowel, which was strongly suspected of having malignant origin. Surgical exploration led to resection of a small jejunal segment with a palpable mass and increased blood flow. Surprisingly, the final diagnosis determined by the pathologist was arteriovenous malformation (AVM). This article is part of an expert video encyclopedia.
Aberrant epigenetic regulators control expansion of human CD34+ hematopoietic stem/progenitor cells
(2013)
Transcription is a tightly regulated process ensuring the proper expression of numerous genes regulating all aspects of cellular behavior. Transcription factors regulate multiple genes including other transcription factors that together control a highly complex gene network. The transcriptional machinery can be “hijacked” by oncogenic transcription factors, thereby leading to malignant cell transformation. Oncogenic transcription factors manipulate a variety of epigenetic control mechanisms to fulfill gene regulatory and cell transforming functions. These factors assemble epigenetic regulators at target gene promoter sequences, thereby disturbing physiological gene expression patterns. Retroviral vector technology and the availability of “healthy” human hematopoietic CD34+ progenitor cells enable the generation of pre-leukemic cell models for the analysis of aberrant human hematopoietic progenitor cell expansion mediated by leukemogenic transcription factors. This review summarizes recent findings regarding the mechanism by which leukemogenic gene products control human hematopoietic CD34+ progenitor cell expansion by disrupting the normal epigenetic program.
Rho-family GTPases like RhoA and Rac-1 are potent regulators of cellular signaling that control gene expression, migration and inflammation. Activation of Rho-GTPases has been linked to podocyte dysfunction, a feature of chronic kidney diseases (CKD). We investigated the effect of Rac-1 and Rho kinase (ROCK) inhibition on progressive renal failure in mice and studied the underlying mechanisms in podocytes. SV129 mice were subjected to 5/6-nephrectomy which resulted in arterial hypertension and albuminuria. Subgroups of animals were treated with the Rac-1 inhibitor EHT1846, the ROCK inhibitor SAR407899 and the ACE inhibitor Ramipril. Only Ramipril reduced hypertension. In contrast, all inhibitors markedly attenuated albumin excretion as well as glomerular and tubulo-interstitial damage. The combination of SAR407899 and Ramipril was more effective in preventing albuminuria than Ramipril alone. To study the involved mechanisms, podocytes were cultured from SV129 mice and exposed to static stretch in the Flexcell device. This activated RhoA and Rac-1 and led via TGFβ to apoptosis and a switch of the cells into a more mesenchymal phenotype, as evident from loss of WT-1 and nephrin and induction of α-SMA and fibronectin expression. Rac-1 and ROCK inhibition as well as blockade of TGFβ dramatically attenuated all these responses. This suggests that Rac-1 and RhoA are mediators of podocyte dysfunction in CKD. Inhibition of Rho-GTPases may be a novel approach for the treatment of CKD.
BACKGROUND: The AGO-ETC trial compared 5-year relapse-free survival of intense dose-dense (IDD) sequential chemotherapy with epirubicin (E), paclitaxel (T), and cyclophosphamide (C) (IDD-ETC) every 2 weeks vs conventional scheduled epirubicin/cyclophosphamide followed by paclitaxel (EC→T) (every 3 weeks) as adjuvant treatment in high-risk breast cancer patients. The objective of this study was to evaluate the safety and efficacy of epoetin alfa in a second randomization of the intense dose-dense arm.
METHODS: One thousand two hundred eighty-four patients were enrolled; 658 patients were randomly assigned to the IDD-ETC treatment group. Within the IDD-ETC group, 324 patients were further randomly assigned to the epoetin alfa group, and 319 were randomly assigned to the non-erythropoiesis-stimulating agent (ESA) control group. Primary efficacy endpoints included change in hemoglobin level from baseline to Cycle 9 and the percentage of subjects requiring red blood cell transfusion. Relapse-free survival, overall survival, and intramammary relapse were secondary endpoints estimated with Kaplan-Meier and Cox regression methods. Except for the primary hypothesis, all statistical tests were two-sided.
RESULTS: Epoetin alfa avoided the decrease in hemoglobin level (no decrease in the epoetin alfa group vs -2.20g/dL change for the control group; P < .001) and statistically significantly reduced the percentage of subjects requiring red blood cell transfusion (12.8% vs 28.1%; P < .0001). The incidence of thrombotic events was 7% in the epoetin alfa arm vs 3% in the control arm. After a median follow-up of 62 months, epoetin alfa treatment did not affect overall survival, relapse-free survival, or intramammary relapse.
CONCLUSIONS: Epoetin alfa resulted in improved hemoglobin levels and decreased transfusions without an impact on relapse-free or overall survival. However, epoetin alfa had an adverse effect, resulting in increased thrombosis.
Small-bowel tumors are rare and account for approximately 5% of all gastrointestinal tumors. Approximately 65% of small-bowel tumors are malignant, and approximately 40% of these tumors are adenocarcinomas. Similar to colorectal adenocarcinoma, premalignant adenomas of the small bowel may progress to carcinoma. This occurs both sporadically and in the context of hereditary tumor syndromes such as familial adenomatous polyposis or hereditary nonpolyposis colorectal cancer (Lynch syndrome). Herein cases with small-bowel adenocarcinomas visualized with both capsule endoscopy and double-balloon enteroscopy are presented. This article is part of an expert video encyclopedia.
Cataract surgery is one of the oldest and the most frequent outpatient clinic operations in medicine performed worldwide. The clouded human crystalline lens is replaced by an artificial intraocular lens implanted into the capsular bag. During the last six decades, cataract surgery has undergone rapid development from a traumatic, manual surgical procedure with implantation of a simple lens to a minimally invasive intervention increasingly assisted by high technology and a broad variety of implants customized for each patient’s individual requirements. This review discusses the major advances in this field and focuses on the main challenge remaining – the treatment of presbyopia. The demand for correction of presbyopia is increasing, reflecting the global growth of the ageing population. Pearls and pitfalls of currently applied methods to correct presbyopia and different approaches under investigation, both in lens implant technology and in surgical technology, are discussed.
Few sequence alignment methods have been designed specifically for integral membrane proteins, even though these important proteins have distinct evolutionary and structural properties that might affect their alignments. Existing approaches typically consider membrane-related information either by using membrane-specific substitution matrices or by assigning distinct penalties for gap creation in transmembrane and non-transmembrane regions. Here, we ask whether favoring matching of predicted transmembrane segments within a standard dynamic programming algorithm can improve the accuracy of pairwise membrane protein sequence alignments. We tested various strategies using a specifically designed program called AlignMe. An updated set of homologous membrane protein structures, called HOMEP2, was used as a reference for optimizing the gap penalties. The best of the membrane-protein optimized approaches were then tested on an independent reference set of membrane protein sequence alignments from the BAliBASE collection. When secondary structure (S) matching was combined with evolutionary information (using a position-specific substitution matrix (P)), in an approach we called AlignMePS, the resultant pairwise alignments were typically among the most accurate over a broad range of sequence similarities when compared to available methods. Matching transmembrane predictions (T), in addition to evolutionary information, and secondary-structure predictions, in an approach called AlignMePST, generally reduces the accuracy of the alignments of closely-related proteins in the BAliBASE set relative to AlignMePS, but may be useful in cases of extremely distantly related proteins for which sequence information is less informative. The open source AlignMe code is available at https://sourceforge.net/projects/alignme/, and at http://www.forrestlab.org, along with an online server and the HOMEP2 data set.
Potential abnormalities in the structure and function of the temporal lobes have been studied much less in bipolar disorder than in schizophrenia. This may not be justified because language-related symptoms, such as pressured speech and flight of ideas, and cognitive deficits in the domain of verbal memory are amongst the hallmark of bipolar disorder (BD), and contribution of temporal lobe dysfunction is therefore likely. In the current study, we examined resting-state functional connectivity (FC) between the auditory cortex (Heschl’s gyrus [HG], planum temporale [PT]) and whole brain using seed correlation analysis in n = 21 BD euthymic patients and n = 20 matched healthy controls and associated it with verbal memory performance. In comparison to controls BD patients showed decreased functional connectivity between Heschl’s gyrus and planum temporale and the left superior and middle temporal gyrus. Additionally, fronto-temporal functional connectivity with the right inferior frontal/precentral gyrus and the insula was increased in patients. Verbal episodic memory deficits in the investigated sample of BD patients and language-related symptoms might therefore be associated with a diminished FC within the auditory/temporal gyrus and a compensatory fronto-temporal pathway.
While necroptosis has for long been viewed as an accidental mode of cell death triggered by physical or chemical damage, it has become clear over the last years that necroptosis can also represent a programmed form of cell death in mammalian cells. Key discoveries in the field of cell death research, including the identification of critical components of the necroptotic machinery, led to a revised concept of cell death signaling programs. Several regulatory check and balances are in place in order to ensure that necroptosis is tightly controlled according to environmental cues and cellular needs. This network of regulatory mechanisms includes metabolic pathways, especially those linked to mitochondrial signaling events. A better understanding of these signal transduction mechanisms will likely contribute to open new avenues to exploit our knowledge on the regulation of necroptosis signaling for therapeutic application in the treatment of human diseases.
Sinnbild der Liebe, Motor des Lebens, faustgroßer Muskelsack – all das ist das Herz. Zahlreiche Sprichworte in allen Sprachen der Welt zeigen, welch zentrale Bedeutung wir Menschen diesem lebenswichtigen Organ immer schon beigemessen haben. Auch wenn wir heute wissen, dass das Herz nicht Sitz der Seele ist – seine zentrale Bedeutung ist unumstritten und ganz real. Auch und gerade dann, wenn es um alternde Herzen geht.
BACKGROUND: In two clinical trials, low-grade fever was observed more frequently after coadministration than after separate administration of two recommended routine pediatric vaccines. Since fever is an important issue with vaccine tolerability, we performed this open-label study on the efficacy and safety of prophylactic use of paracetamol (acetaminophen, Benuron(R)) in children administered routine 7-valent pneumococcal conjugate vaccine (PCV-7) coadministered with hexavalent vaccine (diphtheria-tetanus-acellular pertussis-hepatitis B, polio, Haemophilus influenzae type b vaccine [DTPa-HBV-IPV/Hib]) in Germany.
METHODS: Healthy infants (N = 301) who received a 3-dose infant series of PCV-7 and DTPa-HBV-IPV/Hib plus a toddler dose were randomly assigned 1:1 to prophylactic paracetamol (125 mg or 250 mg suppositories, based on body weight) at vaccination, and at 6--8 hour intervals thereafter, or a control group that received no paracetamol. Rectal temperature and local and other systemic reactions were measured for 4 days post vaccination; adverse events were collected throughout the study.
RESULTS: In the intent-to-treat population, paracetamol reduced the incidence of fever >=38[degree sign]C, but this reduction was only significant for the infant series, with computed efficacy of 43.0% (95% confidence interval [CI]: 17.4, 61.2), and not significant after the toddler dose (efficacy 15.9%; 95% CI: -19.9, 41.3); results were similar in the per protocol (PP) population. Fever >39[degree sign]C was rare during the infant series, such that there were too few cases for assessment. After the toddler dose, paracetamol effectively reduced fever >39[degree sign]C, reaching statistical significance in the PP population only (efficacy 79%; 95% CI: 3.9, 97.7). Paracetamol also reduced reactogenicity, but there were few significant differences between groups after any dose. No vaccine-related serious adverse events were reported.
CONCLUSIONS: Paracetamol effectively prevented fever and other reactions, mainly during the infant series. However, as events were generally mild and of no concern in either group our data support current recommendations to administer paracetamol to treat symptoms only and not for routine prophylaxis.Trial registration: NCT00294294.
Background: Castleman’s disease is a rare lymphoproliferative disorder. It typically presents as mediastinal masses and causes a wide range of clinical symptoms. Histologically, Castleman’s disease is classified as either a hyalinic vascular or plasma cell variant. The prognosis mainly depends on the histological type and broadly varies. We herein report our sonographic findings in a patient with Castleman’s disease, including gray-scale ultrasonography, color Doppler ultrasonography, and sonoelastography ultrasonography, which have not been previously reported in the literature. These findings allowed for a preoperative diagnosis and avoidance of overly aggressive therapy.
Case presentation: A 28-year-old European female patient with unicentric Castleman’s disease of hyalinic vascular type (HV) restricted to the axilla was referred to us because of a 4-month history of a painless, solitary mass located in the left axilla. The patient’s medical history was unremarkable.
Conclusion: Castleman’s disease is a pathologic entity of unknown etiology and pathogenesis. In this case report of unicentric HV-type CD, we demonstrate that typical sonographic findings can lead to a preoperative diagnosis of Castleman’s disease. Core needle biopsy usually allows for a final diagnosis and helps to avoid unnecessary operations and overtreatment.
Abdominale Aortenaneurysmen sind in Industrienationen eine häufige Erkrankung der Personengruppe über 65 Jahre. Diese Dilatationen der abdominalen Aorta zeichnen sich durch eine lokale Inflammation aus, die mit der Infiltration von Immunzellen, dem Verlust von glatten vaskulären Muskelzellen und der Degeneration der extrazellulären Matrix einhergeht. Ursprünglich als Symptom einer Atherosklerose angesehen, sind die Ursachen dieser progressiv verlaufenden Erkrankung nach wie vor nicht vollständig verstanden; obwohl steigendes Alter, männliches Geschlecht, genetische Prädisposition, Rauchen und ein zuvor erlittener Myocardinfarkt als Risikofaktoren identifiziert werden konnten. Der lange Zeit asymptomatische Krankheitsverlauf, die Gefahr einer Ruptur mit häufig letalen Folgen und der Mangel einer effizienten pharmakologischen Therapie machen eine weitere Untersuchung dieser Erkrankung unabdingbar.
Diltiazem ist ein Inhibitor spannungssensitiver L Typ-Calciumkanäle, der seit über 25 Jahren zur Behandlung von arterieller Hypertonie, verschiedener Arrhythmien und Angina pectoris verwendet wird. Im Rahmen der vorliegenden Arbeit sollte untersucht werden, ob Diltiazem auch einen antianeurysmatischen Effekt besitzt. Eine vierwöchige subcutane Infusion des blutdrucksteigernden Hormons Angiotensin II führte nach vier Wochen zur Bildung abdominaler Aortenaneurysmen, sowie zu atherosklerotischen Gefäßveränderungen der thorakalen Aorta Apolipoprotein E (ApoE)-defizienter Mäuse. Eine parallele Therapie mit Diltiazem über das Trinkwasser konnte diese Entwicklung unabhängig vom arteriellen Blutdruck und damit unabhängig von der antihypertensiven Wirkung verhindern. Im Aortenbogen Diltiazem-behandelter Tiere konnte im Rahmen dieses in vivo-Modells nach sechs Tagen eine deutlich geringere lokale Expression proinflammatorischer Cytokine, wie Tumornekrosefaktor-a, Interleukin-1ß (IL1B) und Interleukin-6 (IL6), Chemokine, wie CCL2, und degenerativer Proteasen, wie der Matrix-Metalloprotease 9 (MMP9), festgestellt werden. Dies war die Folge einer reduzierten Anzahl von Macrophagen in der Gefäßwand. Zirkulierende proinflammatorische Cytokine, wie CCL12, konnten im Serum teilweise ebenfalls vermindert nachgewiesen werden.
Obwohl die antihypertensive Wirkung von Diltiazem in glatten vaskulären Muskelzellen vermittelt wird, war es nicht möglich, die Angiotensin II-induzierte Produktion von promigratorischem CCL2 und proinflammatorischem IL6 in isolierten Aortenringen ApoE-defizienter Mäuse oder in glatten vaskulären Muskelzellen der Ratte zu reduzieren. Diltiazem war zudem nicht in der Lage, die CCL2-induzierte Migration proinflammatorischer Ly6C+-Monocyten in vivo zu unterbinden. In isolierten peritonealen Macrophagen ApoE-defizienter Mäuse dagegen, konnte die IL6 induzierte Expression von IL1B- und CCL12-mRNA durch eine Inkubation mit Diltiazem verhindert werden. In der RAW264.7-Zelllinie, die morphologische und funktionelle Merkmale von Monocyten und Macrophagen aufweist, konnte die Dilitiazem-sensitive IL6-induzierte Expression von IL1B-mRNA in vitro ebenfalls nachgewiesen werden. Eine Stimulation mit IL6 war in diesen Zellen jedoch nicht ausreichend, um die Sekretion von IL1B-Protein auszulösen.
Thorakales Aortengewebe wies im Vergleich mit RAW264.7-Zellen eine veränderte Ausstattung spannungssensitiver Calciumkanäle auf. In letzteren fanden sich keine muskelzellspezifischen L-Typ-Calciumkanäle (CACNA1C), aber eine relevante Expression neuronaler P/Q-Typ-Calciumkanäle (CACNA1A). Mittels fluorimetrischer Bestimmung mit Fura-2AM konnte jedoch festgestellt werden, dass die intrazelluläre Calciumkonzentration Diltiazem-behandelter RAW264.7-Zellen unverändert war und der antiinflammatorische Effekt somit calciumunabhängig vermittelt wurde.
Diltiazem war nicht in der Lage, eine Lipopolysaccharid (LPS)-bedingte Inflammation in RAW264.7-Zellen zu unterbinden. Weder die LPS-induzierte Sekretion von IL1B Protein, noch die nucleäre Translokation des Transkriptionsfaktors NF-?B oder die Aktivierung des NF-?B-Promotors konnten durch eine Inkubation der Zellen mit Diltiazem verhindert werden. Diltiazem reduzierte jedoch, die IL6-induzierte Aktivierung des AP 1-Promotors unabhängig von der MAPK1-Phosphorylierung oder der Phosphorylierung und nucleären Translokation des Transkriptionsfaktors STAT3 zu unterbinden. Eine Unterdrückung von c-Jun N-terminale Kinase JNK- oder p38 Proteinkinase-vermittelten Signalwegen ist damit wahrscheinlich.
Das Pirinixinsäurederivat LP105 ist ein neuer Inhibitor der Arachidonat-5-Lipoxygenase (LOX5), der im Rahmen dieser Arbeit erstmals in vivo auf seine antianeurysmatischen Eigenschaften hin untersucht wurde. LOX5 katalysiert die Reaktion von Arachidonsäure zu Leukotrien A4 und kontrolliert damit einen wichtigen Schritt in der Synthese proinflammatorischer Leukotriene. LP105 war im Tiermodell nicht in der Lage die Angiotensin II-induzierte Bildung abdominaler Aortenaneurysmen in ApoE-defizienten Mäusen komplett zu unterbinden, führte aber über die Reduktion der vaskulären Inflammation zu einer deutlich verringerten Krankheitslast. LP105 selbst beeinflusste die mRNA-Expression verschiedener Enzyme des Arachidonsäuremetabolismus nicht, verstärkte jedoch durch die Blockade von LOX5 die Metabolisierung von Arachidonsäure über Arachidonat-15-Lipoxygenase und Cytochrom P450-Enzyme.
Objectives: To describe changes in costs of managing hospitalised patients with acute myeloid leukaemia (AML) after chemotherapy in Germany over 3 yr, with a special focus on prophylaxis and treatment patterns as well as resource use related to invasive fungal infections (IFI).
Methods: The study was conducted as a retrospective, single-centre chart review in patients with AML hospitalised for chemotherapy, neutropenia and infections after myelosuppressive chemotherapy from January 2004 to December 2006 in Germany. The following resource utilisation data were collected: inpatient stay, mechanical ventilation, parenteral feeding, diagnostics, systemic antifungal medication and cost-intensive concomitant medication. Direct medical costs were calculated from hospital provider perspective.
Results: A total of 471 episodes in 212 patients were included in the analysis. Occurrence of IFI decreased from 5.9% in 2004 to 1.9% in 2006. Mean (± standard deviation) hospital stay decreased from 28.7 ± 17.9 d in 2004 to 22.4 ± 11.8 d in 2006. From 2004 to 2006, the use of a single antifungal drug increased from 30.4% to 46.9%, whereas the use of multiple antifungal drugs decreased from 24.4% to 13.1%. The use of liposomal amphotericin B declined between 2004 and 2006 (21.4% vs. 3.8%) and caspofungin between 2005 and 2006 (19.3% vs. 8.1%). Total costs per episode declined from €19051 ± 19024 in 2004 to €13531 ± 9260 in 2006; major reductions were observed in the use of antimycotics and blood products as well as length of hospital stay.
Conclusion: Analysis of real-life data from one single centre in Germany demonstrated a change in antifungal management of patients with AML between 2004/2005 and 2006, accompanied by a decline in total costs.
Mitochondrial cristae morphology is highly variable and altered under numerous pathological conditions. The protein complexes involved are largely unknown or only insufficiently characterized. Using complexome profiling we identified apolipoprotein O (APOO) and apolipoprotein O-like protein (APOOL) as putative components of the Mitofilin/MINOS protein complex which was recently implicated in determining cristae morphology. We show that APOOL is a mitochondrial membrane protein facing the intermembrane space. It specifically binds to cardiolipin in vitro but not to the precursor lipid phosphatidylglycerol. Overexpression of APOOL led to fragmentation of mitochondria, a reduced basal oxygen consumption rate, and altered cristae morphology. Downregulation of APOOL impaired mitochondrial respiration and caused major alterations in cristae morphology. We further show that APOOL physically interacts with several subunits of the MINOS complex, namely Mitofilin, MINOS1, and SAMM50. We conclude that APOOL is a cardiolipin-binding component of the Mitofilin/MINOS protein complex determining cristae morphology in mammalian mitochondria. Our findings further assign an intracellular role to a member of the apolipoprotein family in mammals.
Background: To compare the effect of aprotinin with the effect of lysine analogues (tranexamic acid and ε-aminocaproic acid) on early mortality in three subgroups of patients: low, intermediate and high risk of cardiac surgery.
Methods and Findings: We performed a meta-analysis of randomised controlled trials and observational with the following data sources: Medline, Cochrane Library, and reference lists of identified articles. The primary outcome measure was early (in-hospital/30-day) mortality. The secondary outcome measures were any transfusion of packed red blood cells within 24 hours after surgery, any re-operation for bleeding or massive bleeding, and acute renal dysfunction or failure within the selected cited publications, respectively.
Out of 328 search results, 31 studies (15 trials and 16 observational studies) included 33,501 patients. Early mortality was significantly increased after aprotinin vs. lysine analogues with a pooled risk ratio (95% CI) of 1.58 (1.13–2.21), p<0.001 in the low (n = 14,297) and in the intermediate risk subgroup (1.42 (1.09–1.84), p<0.001; n = 14,427), respectively. Contrarily, in the subgroup of high risk patients (n = 4,777), the risk for mortality did not differ significantly between aprotinin and lysine analogues (1.03 (0.67–1.58), p = 0.90).
Conclusion: Aprotinin may be associated with an increased risk of mortality in low and intermediate risk cardiac surgery, but presumably may has no effect on early mortality in a subgroup of high risk cardiac surgery compared to lysine analogues. Thus, decisions to re-license aprotinin in lower risk patients should critically be debated. In contrast, aprotinin might probably be beneficial in high risk cardiac surgery as it reduces risk of transfusion and bleeding complications.
Calcium-deficiency rickets (CDR) is a metabolic bone disease in children that is characterized by impaired mineralization and severe bone deformities. As CDR is often an endemic phenomenon that is almost exclusively restricted to tropical areas, environmental conditions are currently considered to be a possible predisposing factor for the CDR. Apart from a lack of macronutrients and micronutrients, an oversupply of potentially toxic elements (PTEs) in the soil-plant pathway of the CDR areas is thought to be involved in the aetiology of CDR. This study is the first to comprehensively analyze the impact of the environment on Ca deficiency and the resulting CDR.
To analyze the impact of the environment on CDR in developing countries, a rural region near Kaduna City, northern Nigeria, was chosen as a study area. From this area, cases of CDR have been reported since the early 2000s with a prevalence rate of 5%. Within this study area, 11 study sites, including areas with a high CDR prevalence (HR), a low CDR prevalence (LR) and no CDR prevalence (NR), were visited. In these HR, LR and NR study sites, the bedrock was investigated and the types of parent materials were identified. Local farmers were interviewed to determine the type and intensity of the land use. The soil types were determined along toposequences. The soil textures as well as the clay mineral fractions were determined. The pH values were measured, and the contents of organic carbon (OC) were determined. The potential cation-exchange capacity (CECpot) and the base saturation (BS) were analyzed. Furthermore, the total and plant-available macronutrient, micronutrient and PTE concentrations were measured in the soils. The drinking water was analyzed for pH values and the concentrations of Ca, Se and F were measured. The maize was analyzed for the Ca, Mg, K and P, Se and phytic acid (PA) contents.
The field and laboratory analyses on the bedrock showed that the HR, LR and NR study sites near Kaduna City, northern Nigeria, were underlain by Older Granites. A direct link between the distribution of the bedrock, the parent materials and the prevalence of CDR was not found. Interviews with the local farmers showed that the land use in the Kaduna study area is dominated by the cultivation of cash crops and food crops. Field analyzes on the soil types in the Kaduna study area showed that the distribution of the soil types is highly dependent on the topography and the distribution of the parent materials. In near vicinity to the inselbergs, Lixisols had developed on grus slope deposits. In the lower pediment and plain positions, Acrisols had developed on grus slope deposits and pisolite slope deposits. In the upper plains, Plinthosols had developed on pisolite slope deposits and in the river valleys, Fluvisols had developed on river deposits. Such soil types and soil type distributions are typical for granite-underlain areas in the northern guinea savanna of West Africa. Similarly, the physical soil conditions were representative for the soils of the northern guinea savanna: sandy topsoils, clayey subsoils and relatively high contents of kaolinite clay minerals in the clay fractions. With regard to the geochemical composition, no significant difference was found between the soils of the Kaduna study area and the soils of other granite-underlain areas in West Africa. Only the concentrations of P were considerably low in the soils of the Kaduna study area. However, P deficiency is a typical phenomenon in West African savanna soils and is not restricted to CDR areas. The micronutrient concentrations in the soils were low, but not critically low. Laboratory analyses on the amounts of PTEs showed that compared to worldwide background levels and international critical limits the PTE concentrations were very low in the soils of the Kaduna study area. In the drinking water, neither a significant lack of macronutrients and micronutrients, nor a noticeable oversupply of PTEs was found. The maize in the HR, LR and NR study sites contained normal contents of Mg, K and P, low contents of Ca and Se as well as slightly elevated concentrations of PA compared to West African food composition tables. Comparisons between the mineral contents of traditional and modern maize cultivars showed that the traditional maize cultivars contained significantly higher contents of Ca and noticeably lower concentrations of PA than the modern maize cultivars.
A direct link between the environmental conditions and the CDR in the Kaduna study area was considered unlikely, as neither a statistically significant lack of macronutrients and micronutrients, nor a statistically significant oversupply of PTEs was found in the environment of this area. Instead, the results indicated that the nutrition rather than the environmental conditions that impacts the prevalence of CDR.
The proportion of elderly women in the population is rising, and in tandem, the incidence of breast cancer rises with age. Because of health and tolerability concerns, as well as life expectancy, physicians may be reluctant to advise a standard treatment regimen for elderly patients with metastatic breast cancer. To elucidate this issue, we performed a literature review of clinical studies that included women with metastatic breast cancer who were over the age of 65. Our results show that although little clinical evidence exists, what is available suggests that standard treatment is tolerated and beneficial for patients meeting certain criteria. A geriatric assessment may identify specific patient groups (independent, dependent, or frail) and thereby guide treatment. Treatment recommendations for elderly patients with metastatic breast cancer are sparse, although first-line endocrine treatment, usually aromatase inhibitors or tamoxifen, is recommended for hormone-sensitive disease. In general, the evidence from clinical studies suggests that aromatase inhibitors are more effective than either tamoxifen or megestrol acetate as first- or second-line treatment in postmenopausal women with metastatic breast cancer. Ultimately, quality of life, treatment effects, and comorbidities are important aspects in this population and may guide treatment choice. To provide evidence-based treatment guidance, future clinical trials should include more patients over the age of 65 years.
Introduction. The use of ultrasound during resuscitation is emphasized in the latest European resuscitation council guidelines of 2013 to identify treatable conditions such as pericardial tamponade. The recommended standard treatment of tamponade in various guidelines is pericardiocentesis. As ultrasound guidance lowers the complication rates and increases the patient’s safety, pericardiocentesis should be performed under ultrasound guidance. Acute care physicians actually need to train emergency pericardiocentesis. Methods. We describe in detail a pericardiocentesis ultrasound model, using materials at a cost of about 60 euros. During training courses of focused echocardiography n=67, participants tested the phantom and completed a 16-item questionnaire, assessing the model using a visual analogue scale (VAS). Results. Eleven of fourteen questions were answered with a mean VAS score higher than 60% and thus regarded as showing the strengths of the model. Unrealistically outer appearance and heart shape were rated as weakness of the model. A total mean VAS score of all questions of 63% showed that participants gained confidence for further interventions. Conclusions. Our low-cost pericardiocentesis model, which can be easily constructed, may serve as an effective training tool of ultrasound-guided pericardiocentesis for acute and critical care physicians.
Background: Lung ultrasound has become an emerging tool in acute and critical care medicine. Combined theoretical and hands-on training has been required to teach ultrasound diagnostics. Current computer technology allows for display, explanation, and animation of information in a remote-learning environment.
Objective: Development and assessment of an e-learning program for lung ultrasound.
Methods: An interactive online tutorial was created. A prospective learning success study was conducted with medical students using a multiple-choice test (Trial A). This e-learning program was used as preparation for a certified course followed by an evaluation of trained doctors (Trial B) by linear analogue scales. Pretests were compared with postcourse tests and sustainability tests as well as a posttest of a one-day custom classroom training.
Results: In Trial A, during the learning success study (n = 29), the increase of correct answers was 11.7 to 17/20 in the post-test and to 16.6/20 in the sustainability test (relative change 45.1%, P < 0.0001). E-learning almost equalled scores of classroom-based training regarding gain and retention of factual knowledge. In Trial B, nineteen participating doctors found a 79.5% increase of knowledge (median, 95% CI: 69%; 88%).
Conclusion: The basics of lung ultrasound can be taught in a highly effective manner using e-learning.
Background: The pro-inflammatory status of the elderly triggers most of the age-related diseases such as cancer and atherosclerosis. Atherosclerosis, the leading cause world wide of morbidity and death, is an inflammatory disease influenced by life-style and genetic host factors. Stimuli such as oxLDL or microbial ligands have been proposed to trigger inflammation leading to atherosclerosis. It has recently been shown that oxLDL activates immune cells via the Toll-like receptor (TLR) 4/6 complex. Several common single nucleotide polymorphisms (SNPs) of the TLR system have been associated with atherosclerosis. To investigate the role of TLR-6 we analyzed the association of the TLR-6 SNP Pro249Ser with atherogenesis.
Results: Genotyping of two independent groups with CAD, as well as of healthy controls revealed a significant association of the homozygous genotype with a reduced risk for atherosclerosis (odds ratio: 0.69, 95% CI 0.51-0.95, P = 0.02). In addition, we found a trend towards an association with the risk of restenosis after transluminal coronary angioplasty (odds ratio: 0.53, 95% CI 0.24-1.16, P = 0.12). In addition, first evidence is presented that the frequency of this protective genotype increases in a healthy population with age. Taken together, our results define a role for TLR-6 and its genetic variations in modulating the inflammatory response leading to atherosclerosis.
Conclusions: These results may lead to a better risk stratification, and potentially to an improved prophylactic treatment of high-risk populations. Furthermore, the protective effect of this polymorphism may lead to an increase of this genotype in the healthy elderly and may therefore be a novel genetic marker for the well-being during aging.
Background & Aims: Genetic variations near the interferon lambda 3 gene (IFNL3, IL28B) are the most powerful predictors for sustained virologic response (SVR) in patients with chronic hepatitis C virus (HCV) infection, compared to other biochemical or histological baseline parameters. We evaluated whether the interplay of both IFNL3 polymorphisms rs12979860 and rs8099917 together with non-genetic clinical factors contributes to the predictive role of these genetic variants.
Methods: The cohort comprised 1,402 patients of European descent with chronic HCV type 1 infection. 1,298 patients received interferon-based antiviral therapy, and 719 (55%) achieved SVR. The IFNL3 polymorphisms were genotyped by polymerase chain reaction and melting curve analysis.
Results: A significant correlation was found between the IFNL3 polymorphisms and biochemical as well as virologic predictors of treatment outcome such as ALT, GGT, cholesterol, and HCV RNA levels. In multivariate regression analysis, IFLN3 SNPs, HCV RNA levels, and the GGT/ALT ratio were independent predictors of SVR. Dependent on the GGT/ALT ratio and on the HCV RNA concentration, significant variations in the likelihood for achieving SVR were observed in both, carriers of the responder as well as non-responder alleles.
Conclusions: Our data support a clear association between IFNL3 genotypes and baseline parameters known to impact interferon responsiveness. Improved treatment outcome prediction was achieved when these predictors were considered in combination with the IFNL3 genotype.
Ataxin-2 (ATXN2) is implicated mainly in mRNA processing. Some ATXN2 associates with receptor tyrosine kinases (RTK), inhibiting their endocytic internalization through interaction of proline-rich domains (PRD) in ATXN2 with SH3 motifs in Src. Gain of function of ATXN2 leads to neuronal atrophy in the diseases spinocerebellar ataxia type 2 (SCA2) and amyotrophic lateral sclerosis (ALS). Conversely, ATXN2 knockout (KO) mice show hypertrophy and insulin resistance. To elucidate the influence of ATXN2 on trophic regulation, we surveyed interactions of ATXN2 with SH3 motifs from numerous proteins and observed a novel interaction with Grb2. Direct binding in glutathione S-transferase (GST) pull-down assays and coimmunoprecipitation of the endogenous proteins indicated a physiologically relevant association. In SCA2 patient fibroblasts, Grb2 more than Src protein levels were diminished, with an upregulation of both transcripts suggesting enhanced protein turnover. In KO mouse embryonal fibroblasts (MEF), the protein levels of Grb2 and Src were decreased. ATXN2 absence by itself was insufficient to significantly change Grb2-dependent signaling for endogenous Ras levels, Ras-GTP levels, and kinetics as well as MEK1 phosphorylation, suggesting that other factors compensate for proliferation control. In KO tissue with postmitotic neurons, a significant decrease of Src protein levels is prominent rather than Grb2. ATXN2 mutations modulate the levels of several components of the RTK endocytosis complex and may thus contribute to alter cell proliferation as well as translation and growth.
In Chinese medicine acupuncture points are treated by physical stimuli to counteract various diseases. These stimuli include mechanical stress as applied during the needle manipulation or tuina, high temperatures as applied during moxibustion, and red laser light applied during laser acupuncture. This study aimed to investigate cellular responses to stimuli that might occur in the tissue of acupuncture points. Since they have a characteristically high density of mast cells that degranulate in response to acupuncture, we asked whether these processes lead to ATP release. We tested in in vitro experiments on mast cells of the human mast-cell line HMC-1 the effects of the physical stimuli; mechanical stress was applied by superfusion of the cells with hypotonic solution, heat was applied by incubation of the cells at 52°C, and red laser light of 657 nm was used for irradiation. We demonstrate that all the stimuli induce ATP release from model human mast HMC-1 cells, and this release is associated with an intracellular free Ca2+ rise. We hypothesize that ATP released from mast cells supplements the already known release of ATP from keratinocytes and, by acting on P2X receptors, it may serve as initial mediator of acupuncture-induced analgesia.
Although motor tasks at most times do not require much attention, there are findings that attention can alter neuronal activity not only in higher motor areas but also within the primary sensorimotor cortex. However, these findings are equivocal as attention effects were investigated only in either the dominant or the nondominant hand; attention was operationalized either as concentration (i.e., attention directed to motor task) or as distraction (i.e., attention directed away from motor task), the complexity of motor tasks varied and almost no left-handers were studied. Therefore, in this study, both right- and left-handers were investigated with an externally paced button press task in which subjects typed with the index finger of the dominant, nondominant, or both hands. We introduced four different attention levels: attention-modulation-free, distraction (counting backward), concentration on the moving finger, and divided concentration during bimanual movement. We found that distraction reduced neuronal activity in both contra- and ipsilateral primary sensorimotor cortex when the nondominant hand was tapping in both handedness groups. At the same time, distraction activated the dorsal frontoparietal attention network and deactivated the ventral default network. We conclude that difficulty and training status of both the motor and cognitive task, as well as usage of the dominant versus the nondominant hand, are crucial for the presence and magnitude of attention effects on sensorimotor cortex activity. In the case of a very simple button press task, attention modulation is seen for the nondominant hand under distraction and in both handedness groups.
Cellular cytotoxicity is the hallmark of NK cells mediating both elimination of virus-infected or malignant cells, and modulation of immune responses. NK cytotoxicity is triggered upon ligation of various activating NK cell receptors. Among these is the C-type lectin-like receptor NKp80 which is encoded in the human Natural Killer Gene Complex (NKC) adjacent to its ligand, activation-induced C-type lectin (AICL). NKp80-AICL interaction promotes cytolysis of malignant myeloid cells, but also stimulates the mutual crosstalk between NK cells and monocytes.
While many activating NK cell receptors pair with ITAM-bearing adaptors, we recently reported that NKp80 signals via a hemITAM-like sequence in its cytoplasmic domain. Here we molecularly dissect the NKp80 hemITAM and demonstrate that two non-consensus amino acids, in particular arginine 6, critically impair both hemITAM phosphorylation and Syk recruitment. Impaired Syk recruitment results in a substantial attenuation of cytotoxic responses upon NKp80 ligation. Reconstituting the hemITAM consensus or Syk overexpression resulted in robust NKp80-mediated responsiveness. Collectively, our data provide a molecular rationale for the restrained activation potential of NKp80 and illustrate how subtle alterations in signaling motifs determine subsequent cellular responses. They also suggest that non-consensus alterations in the NKp80 hemITAM, as commonly present among mammalian NKp80 sequences, may have evolved to dampen NKp80-mediated cytotoxic responses toward AICL-expressing cells.
Background: The activating NK receptor NKp80 triggers cytotoxicity by human NK cells via a cytoplasmic hemITAM sequence.
Results: A non-consensus hemITAM residue impairs the capacity of NKp80 to recruit Syk kinase and to trigger cytotoxicity.
Conclusion: Unlike typical hemITAM receptors, NKp80 does not efficiently recruit Syk kinase resulting in attenuated effector responses.
Significance: An attenuated cytotoxic responsiveness critically impacts on the immunomodulatory function of NKp80.
Genetic or pharmacological ablation of toll-like receptor 2 (TLR2) protects against myocardial ischemia/reperfusion injury (MI/R). However, the endogenous ligand responsible for TLR2 activation has not yet been detected. The objective of this study was to identify HMGB1 as an activator of TLR2 signalling during MI/R. C57BL/6 wild-type (WT) or TLR2(-/-)-mice were injected with vehicle, HMGB1, or HMGB1 BoxA one hour before myocardial ischemia (30 min) and reperfusion (24 hrs). Infarct size, cardiac troponin T, leukocyte infiltration, HMGB1 release, TLR4-, TLR9-, and RAGE-expression were quantified. HMGB1 plasma levels were measured in patients undergoing coronary artery bypass graft (CABG) surgery. HMGB1 antagonist BoxA reduced cardiomyocyte necrosis during MI/R in WT mice, accompanied by reduced leukocyte infiltration. Injection of HMGB1 did, however, not increase infarct size in WT animals. In TLR2(-/-)-hearts, neither BoxA nor HMGB1 affected infarct size. No differences in RAGE and TLR9 expression could be detected, while TLR2(-/-)-mice display increased TLR4 and HMGB1 expression. Plasma levels of HMGB1 were increased MI/R in TLR2(-/-)-mice after CABG surgery in patients carrying a TLR2 polymorphism (Arg753Gln). We here provide evidence that absence of TLR2 signalling abrogates infarct-sparing effects of HMGB1 blockade.
Trotz zunehmender Verbesserungen in der Diagnostik und Therapie von Krebserkrankungen leiden onkologische Patienten häufig unter gravierenden tumorund therapiebedingten Symptomen und Nebenwirkungen wie Fatigue, Reduktion der Leistungsfähigkeit und Lebensqualität (Courneya, 2003a; Crevenna et al., 2002; Ferriset al., 2009). Zahlreiche Untersuchungen und Übersichtsarbeiten zeigen, dass körperliche Aktivität in den verschiedenen Phasen der Krebstherapie möglich ist und zu einer Reduktion der Nebenwirkungen sowie zu einer Verbesserung der Lebensqualität und Leistungsfähigkeit führen kann (Cramp & Byron-Daniel, 2012; Jones & Peppercorn, 2010; Mishra et al., 2012b; Schmitz et al., 2010). In aktuellen Leitlinien wird körperliche Aktivität deshalb als wichtige supportive Therapiemaßnahme während der Akuttherapie und im Rahmen der Nachsorge sowie Rehabilitation empfohlen. Analog der zunehmenden Individualisierung medizinischer Diagnostik- und Therapiestrategien in der Onkologie (z. B. vergleichbare oder sequentielle Therapieregime, targeted therapies, Patientenwunsch), gibt es inzwischen auch im Bereich der Sportmedizin Forderungen nach individuell angepassten, effektiven körperlichen Trainingsprogrammen (Jensen et al., 2011). Bei der Erarbeitung dieser Bewegungsangebote sollten Informationen zur Einschätzung der körperlichen Leistungsfähigkeit sowie zu den individuellen persönlichen und medizinischen Voraussetzungen der Betroffenen berücksichtigt werden. Entsprechend muss bei der Planung der körperlichen Aktivität auch die aktuelle Behandlungsphase im Rahmen der onkologischen Therapien einbezogen werden. Neben der zeitlichen Einteilung der Therapiephasen in Akut- oder Rehabilitationsphase gibt es die Möglichkeit, den Therapieprozess in Abhängigkeit der Heilungsaussicht einzuordnen. Dabei wird die Prognose einer Tumorerkrankung in Abhängigkeit des Tumorstadiums, des Lymphknotenbefalls und der möglichen Metastasierung in einen heilbaren (kurativen) und nicht heilbaren (palliativen) Therapieansatz eingestuft. Während ein Großteil der Studien die Wirkung bewegungstherapeutischer Interventionen bei Patienten mit kurativem Therapieansatz untersucht, gibt es bisher nur sehr wenig Untersuchungen bei unheilbar kranken Tumorpatienten (Albrecht & Taylor, 2012). Infolgedessen sind Aussagen zu prognosebezogenen Informationen über die individuelle Leistungsfähigkeit und zu unterschiedlichen physischen und psychischen Reaktionenaufgrund körperlicher Aktivität bei dieser Patientengruppe bisher nur bedingt möglich und erlauben folglich keine zielgruppenspezifischen Empfehlungen.
Angesichts dieses Forschungsdefizits ist das Kernziel der vorliegenden Arbeit, mögliche Unterschiede von Lebensqualität, Fatigue und aerober Kapazität (VO2peak) in Abhängigkeit der Heilungsaussicht (kurativ/palliativ) initial zu identifizieren und gleichzeitig die jeweiligen Veränderungen im Rahmen der Intervention über den Gesamtuntersuchungszeitraum zu überprüfen.
Initial konnten 300 onkologische Patienten (histologisch gesichertes Malignom) mit unterschiedlichen Krebsentitäten, in verschiedenen Behandlungsphasen, mit bekannter klinischer Heilungsprognose (kurativ/palliativ) und unter Berücksichtigung definierter Ein- und Ausschlusskriterien in die Untersuchung eingeschlossen werden. Mit dem Ziel einer individuellen Sportberatung und Trainingsplangestaltung absolvierten die Studienteilnehmer eine sportmedizinische Gesundheits- und Leistungsdiagnostik zur Ermittlung der Ausdauerleistungsfähigkeit und Bestimmung des Trainingsbereichs. Die Messungen erfolgten auf dem Fahrradergometer (0W; 25W Inkrement; 3 Minuten) und umfassten Herzfrequenz, Blutdruck, maximale Sauerstoffaufnahmefähigkeit (VO2peak), Laktatkonzentration und subjektives Belastungsempfinden (Borg Skala). Baseline- und identische Wiederholungs-untersuchungen nach 4-6 und nach 16-20 Wochen dienten gleichzeitig der Erfassung der subjektiven Parameter Lebensqualität und Fatigue (EORTC QLQ-C30) (Aaronson et al., 1993). Der Trainingsplan wurde unter Einbeziehung persönlicher Präferenzen, individueller Leistungsfähigkeit und Empfehlungen zur Gesundheitsprävention der WHO (als Orientierung für den Trainingsumfang von 150 min/Wo.) erstellt und dem Patienten in einem ca. 20minütigen Beratungsgespräch erläutert. Art, Umfang und Häufigkeit des mindestens mit moderater Intensität absolvierten Ausdauertrainings wurde durch die Patienten in einem Trainingstagebuch dokumentiert. Die Gruppenzuteilung erfolgte in Abhängigkeit der Heilungsprognose (kurativ/palliativ) unter Verwendung des TNM-Systems. Patienten mit der Prognose „heilbar“ wurden der kurativen Stichprobe zugeteilt, während Patienten mit histologisch gesichertem Nachweis von Metastasen (M1) als palliativ eingestuft wurden.
Referenzwerte waren für die VO2peak: alters- und geschlechtsentsprechende Normdaten (Median) des American College of Sports Medicine und für die Daten des EORTCQLQ-C30: das Manual „EORTC QLQ-C30 Reference Values“ einer EORTCArbeitsgruppe (Scott, 2008). Die Dateneingabe und die Aufbereitung der Rohdaten erfolgte mit Hilfe von Microsoft Excel. Für die statistische Auswertung wurden alle statistischen Analysen anschließend mithilfe der Statistikprogramme SPSS 19.0 (SPSS Inc., Chicago, IL, USA) und „BIAS für Windows“, Version 10, 2012, Universität Frankfurt) durchgeführt. Das Signifikanzniveau wurde a priori auf p<0,05 festgelegt.
Insgesamt 158 Patienten (99 kurativ, 59 palliativ; 54,9±11,1 Jahre, 108 ♀, 50 ♂) nahmen an allen drei Untersuchungen teil. Der parameterfreie Mann-Whitney-Test zeigte sowohl für Lebensqualität als auch Fatigue-Symptomatik keine signifikanten Unterschiede bei der Eingangsuntersuchung zwischen kurativen und palliativen Teilnehmern. Für die VO2peak ergab der parametrische T-Test ebenfalls keine Unterschiede bei den Initialwerten. Nach Abschluss der Intervention zeigten sich in beiden Patientengruppen sowohl bei der Lebensqualität als auch der Fatigue-Symptomatik signifikante Verbesserungen über den gesamten Untersuchungszeitraum. Anschließende post-hoc-Tests ergaben keine signifikanten Gruppenunterschiede bezüglich der Entwicklung während der verschiedenen Untersuchungszeiträume und der Differenz von Initial- und Abschlusswert. Die Varianzanalyse mit Messwiederholung (Anova) zeigte sowohl für Kurativ- als auch Palliativpatienten signifikante Veränderungen der VO2peak über die Zeit. Einen Haupteffekt im Bezug auf die Gruppe oder eine Interaktion von Zeit und Gruppe gab es dabei nicht. Folglich entwickelten sich beide Gruppen über den Untersuchungszeitraum vergleichbar.
Die vorliegenden Ergebnisse zeigen, dass die Heilungsprognose, kurativ oder palliativ, keinen unterschiedlichen Einfluss auf die Trainierbarkeit der Betroffenen zu haben scheint. Körperliches Training führte bei beiden Patientengruppen dieser Studie zu signifikanten Verbesserungen der Zielparameter. Ein Vergleich der vorliegenden Daten mit bisherigen Untersuchungsergebnissen ist aufgrund der aktuell geringen Anzahl an Studien mit Palliativpatienten und einer bisher nicht einheitlichen Palliativ-Definition schwierig.
Die sporttherapeutische Beratung, welche neben der Vermittlung von Trainingsumfang und –intensität insbesondere Trainingsziele und deren Wirksamkeit aufzeigen soll, kann Patienten und ihrem Umfeld helfen, den Stellenwert von körperlichem Training zuverstehen und bestenfalls die Compliance erhalten. Darüber hinaus kann die allgemeine Leitlinien-Empfehlung von 150 Minuten moderates Ausdauertraining pro Woche als grober Richtwert bestätigt werden. Unterschiedlich hohe Trainingsumfänge in Abhängigkeit initialer Leistungsfähigkeit weisen indessen darauf hin, dass individuelle Trainingsempfehlungen zu bevorzugen sind. Als Konsequenz aus diesen Ergebnissen ist zu empfehlen, dass sich zukünftig körperliche Aktivität als unverzichtbarer Bestandteil des supportiven Therapieangebotes für Krebspatienten mit fortgeschrittener Erkrankung, speziell bei palliativ eingestuften Patienten, etabliert.
Weitere Untersuchungen zu diesem Thema sollten insbesondere darauf abzielen, Dosis-Wirkungs-Zusammenhänge zu ermitteln und diese in symptom- und entitätsspezifische Empfehlungen zu integrieren.
Natural Killer Gene Complex (NKC)–encoded C-type lectin-like receptors (CTLRs) are expressed on various immune cells including T cells, NK cells and myeloid cells and thereby contribute to the orchestration of cellular immune responses. Some NKC-encoded CTLRs are grouped into the C-type lectin family 2 (CLEC2 family) and interact with genetically linked CTLRs of the NKRP1 family. While many CLEC2 family members are expressed by hematopoietic cells (e.g. CD69 (CLEC2C)), others such as the keratinocyte-associated KACL (CLEC2A) are specifically expressed by other tissues. Here we provide the first characterization of the orphan gene CLEC2L. In contrast to other CLEC2 family members, CLEC2L is conserved among mammals and located outside of the NKC. We show that CLEC2L-encoded CTLRs are expressed as non-glycosylated, disulfide-linked homodimers at the cell surface. CLEC2L expression is fairly tissue-restricted with a predominant expression in the brain. Thus CLEC2L-encoded CTLRs were designated BACL (brain-associated C-type lectin). Combining in situ hybridization and immunohistochemistry, we show that BACL is expressed by neurons in the CNS, with a pronounced expression by Purkinje cells. Notably, the CLEC2L locus is adjacent to another orphan CTLR gene (KLRG2), but reporter cell assays did neither indicate interaction of BACL with the KLRG2 ectodomain nor with human NK cell lines or lymphocytes. Along these lines, growth of BACL-expressing tumor cell lines in immunocompetent mice did not provide evidence for an immune-related function of BACL. Altogether, the CLEC2L gene encodes a homodimeric cell surface CTLR that stands out among CLEC2 family members by its conservation in mammals, its biochemical properties and the predominant expression in the brain. Future studies will have to reveal insights into the functional relevance of BACL in the context of its neuronal expression.
Protein quality control systems (PQC), i.e. UPS and aggresome-autophagy pathway, have been suggested to be a promising target in cancer therapy. Simultaneous pharmacological inhibition of both pathways have shown increase efficacy in various tumors, such as ovarian and colon carcinoma. Here, we investigate the effect of concomitant inhibition of 26S proteasome by FDA-approved inhibitor Bortezomib, and HDAC6, as key mediator of the aggresome-autophagy system, by the highly specific inhibitor ST80 in rhabdomyosarcoma (RMS) cell lines. We demonstrated that simultaneous inhibition of 26S proteasome and selective aggresome-autophagy pathway significantly increases apoptosis in all tested RMS cell lines. Interestingly, we observed that a subpopulation of RMS cells was able to survive the co-treatment and, upon drug removal, to recover similarly to untreated cells. In this study, we identified co-chaperone BAG3 as the key mediator of this recovery: BAG3 is transcriptionally up-regulated specifically in the ST80/Bortezomib surviving cells and mediates clearance of cytotoxic protein aggregates by selective autophagy. Impairment of the autophagic pathway during the recovery phase, both by conditional knock-down of ATG7 or by inhibition of lysosomal degradation by BafylomicinA1, triggers accumulation of insoluble protein aggregates, loss of cell recovery and cell death similarly to stable short harpin RNA (shRNA) BAG3 knock-down. Our results are the first demonstration that BAG3 mediated selective autophagy is engaged to cope with proteotoxicity induced by simultaneous inhibition of constitutive PQC systems in cancer cell lines during cell recovery. Moreover, our data give new insights in the regulation of constitutive and on demand PQC mechanisms pointing to BAG3 as a promising target in RMS therapy.
Background and Aims: In patients with advanced liver cirrhosis due to chronic hepatitis C virus (HCV) infection antiviral therapy with peginterferon and ribavirin is feasible in selected cases only due to potentially life-threatening side effects. However, predictive factors associated with hepatic decompensation during antiviral therapy are poorly defined.
Methods: In a retrospective cohort study, 68 patients with HCV-associated liver cirrhosis (mean MELD score 9.18±2.72) were treated with peginterferon and ribavirin. Clinical events indicating hepatic decompensation (onset of ascites, hepatic encephalopathy, upper gastrointestinal bleeding, hospitalization) as well as laboratory data were recorded at baseline and during a follow up period of 72 weeks after initiation of antiviral therapy. To monitor long term sequelae of end stage liver disease an extended follow up for HCC development, transplantation and death was applied (240weeks, ±SD 136weeks).
Results: Eighteen patients (26.5%) achieved a sustained virologic response. During the observational period a hepatic decompensation was observed in 36.8%. Patients with hepatic decompensation had higher MELD scores (10.84 vs. 8.23, p<0.001) and higher mean bilirubin levels (26.74 vs. 14.63 µmol/l, p<0.001), as well as lower serum albumin levels (38.2 vs. 41.1 g/l, p = 0.015), mean platelets (102.64 vs. 138.95/nl, p = 0.014) and mean leukocytes (4.02 vs. 5.68/nl, p = 0.002) at baseline as compared to those without decompensation. In the multivariate analysis the MELD score remained independently associated with hepatic decompensation (OR 1.56, 1.18–2.07; p = 0.002). When the patients were grouped according to their baseline MELD scores, hepatic decompensation occurred in 22%, 59%, and 83% of patients with MELD scores of 6–9, 10–13, and >14, respectively. Baseline MELD score was significantly associated with the risk for transplantation/death (p<0.001).
Conclusions: Our data suggest that the baseline MELD score predicts the risk of hepatic decompensation during antiviral therapy and thus contributes to decision making when antiviral therapy is discussed in HCV patients with advanced liver cirrhosis.
Metastasic breast cancer is the leading cause of death by malignancy in women worldwide. Tumor metastasis is a multistep process encompassing local invasion of cancer cells at primary tumor site, intravasation into the blood vessel, survival in systemic circulation, and extravasation across the endothelium to metastasize at a secondary site. However, only a small percentage of circulating cancer cells initiate metastatic colonies. This fact, together with the inaccessibility and structural complexity of target tissues has hampered the study of the later steps in cancer metastasis. In addition, most data are derived from in vivo models where critical steps such as intravasation/extravasation of human cancer cells are mediated by murine endothelial cells. Here, we developed a new mouse model to study the molecular and cellular mechanisms underlying late steps of the metastatic cascade. We have shown that a network of functional human blood vessels can be formed by co-implantation of human endothelial cells and mesenchymal cells, embedded within a reconstituted basement membrane-like matrix and inoculated subcutaneously into immunodeficient mice. The ability of circulating cancer cells to colonize these human vascularized organoids was next assessed in an orthotopic model of human breast cancer by bioluminescent imaging, molecular techniques and immunohistological analysis. We demonstrate that disseminated human breast cancer cells efficiently colonize organoids containing a functional microvessel network composed of human endothelial cells, connected to the mouse circulatory system. Human breast cancer cells could be clearly detected at different stages of the metastatic process: initial arrest in the human microvasculature, extravasation, and growth into avascular micrometastases. This new mouse model may help us to map the extravasation process with unprecedented detail, opening the way for the identification of relevant targets for therapeutic intervention.
Polo-like kinase 1, a pivotal regulator of mitosis and cytokinesis, is highly expressed in a broad spectrum of tumors and its expression correlates often with poor prognosis, suggesting its potential as a therapeutic target. p53, the guardian of the genome, is the most important tumor suppressor. In this review, we address the intertwined relationship of these two key molecules by fighting each other as eternal rivals in many signaling pathways. p53 represses the promoter of Polo-like kinase 1, whereas Polo-like kinase 1 inhibits p53 and its family members p63 and p73 in cancer cells lacking functional p53. Plk1 inhibitors target all rapidly dividing cells irrespective of tumor cells or non-transformed normal but proliferating cells. Upon treatment with Plk1 inhibitors, p53 in tumor cells is activated and induces strong apoptosis, whereas tumor cells with inactive p53 arrest in mitosis with DNA damage. Thus, inactive p53 is not associated with a susceptible cytotoxicity of Polo-like kinase 1 inhibition and could rather foster the induction of polyploidy/aneuploidy in surviving cells. In addition, compared to the mono-treatment, combination of Polo-like kinase 1 inhibition with anti-mitotic or DNA damaging agents boosts more severe mitotic defects, effectually triggers apoptosis and strongly inhibits proliferation of cancer cells with functional p53. In this regard, restoration of p53 in tumor cells with loss or mutation of p53 will reinforce the cytotoxicity of combined Polo-like kinase 1 therapy and provide a proficient strategy for combating relapse and metastasis of cancer.
Hintergrund: Das Burkitt Lymphom und das Diffus großzellige B-Zell Lymphom können überlappende morphologische und immunhistochemische Eigenschaften aufweisen. Eine Differenzierung beider Entitäten ist klinisch relevant. Mit Hilfe von Genexpressionsanalysen an kryo-konservierten Proben hochmaligner B-Zell Lymphome, bestehend aus Burkitt Lymphomen und Diffus großzelligen B-Zell Lymphomen, gelang 2006 die molekulare Definition des Burkitt Lymphoms (mBL) mit einer burkittspezifischen Gensignatur (Genchip-Klassifikator). Demgegenüber wurden Proben, die nicht diese Signatur aufwiesen als non-mBL bezeichnet. Proben, die weder mBL noch non-mBL klassifiziert wurden, wurden als intermediär eingestuft.
Ziel: Entwicklung einer Methode zur Unterscheidung von mBL und non-mBL mittels quantitativer Echtzeit-Polymerase Kettenreaktion (qPCR) durch die Etablierung eines Assays-Sets einer kleinen Anzahl von Genen der mBL-Signatur an formalinfixiertem, in paraffineingebettetem (FFPE) Gewebe.
Methoden: An 116 Proben, bestehend aus mBL, non-mBL und intermediären Fällen (entsprechend der Genchip-Klassifikation) wurden qPCR Messungen für sechs Gene und ein Referenzgen durchgeführt. Die Expressionsmessungen wurden auf den vorhandenen Genchip-Klassifikator projiziert.
Ergebnisse: 90 von 116 Proben konnten mit dem qPCR-Klassifikator klassifiziert werden. Bei 22 Proben kam es zu Messausfällen. 4 Fälle wurden bioinformatisch ausgesondert.13 von 14 mBL, 59 von 61 non-mBL und 8 von15 intermediären Fällen wurden identisch zu dem Genchip-Klassifikator bewertet.
Diskussion: Der entwickelte qPCR-Klassifikator ist eine objektive, schnelle und kosteneffiziente diagnostische Herangehensweise zur Bestimmung des mBL. Nicht alle FFPE-Proben waren mit dem qPCR Klassifikator eindeutig auswertbar und für eine Klassifikation zu nutzen. Eine Einflussgröße hierbei stellt das Alter der Proben dar. Mit Hilfe dieser Untersuchung können retrospektive Analysen durchgeführt werden. Der Klassifikator kann zusätzlich zur Morphologie und Immunhistochemie mit eindeutiger Klassifikation von 93% (mBL) und 97% (non-mBL) angewendet werden.
Biomarkers and bacterial pneumonia risk in patients with treated HIV infection: a case-control study
(2013)
Background: Despite advances in HIV treatment, bacterial pneumonia continues to cause considerable morbidity and mortality in patients with HIV infection. Studies of biomarker associations with bacterial pneumonia risk in treated HIV-infected patients do not currently exist.
Methods: We performed a nested, matched, case-control study among participants randomized to continuous combination antiretroviral therapy (cART) in the Strategies for Management of Antiretroviral Therapy trial. Patients who developed bacterial pneumonia (cases) and patients without bacterial pneumonia (controls) were matched 1:1 on clinical center, smoking status, age, and baseline cART use. Baseline levels of Club Cell Secretory Protein 16 (CC16), Surfactant Protein D (SP-D), C-reactive protein (hsCRP), interleukin-6 (IL-6), and d-dimer were compared between cases and controls.
Results: Cases (n = 72) and controls (n = 72) were 25.7% female, 51.4% black, 65.3% current smokers, 9.7% diabetic, 36.1% co-infected with Hepatitis B/C, and 75.0% were on cART at baseline. Median (IQR) age was 45 (41, 51) years with CD4+ count of 553 (436, 690) cells/mm3. Baseline CC16 and SP-D were similar between cases and controls, but hsCRP was significantly higher in cases than controls (2.94 µg/mL in cases vs. 1.93 µg/mL in controls; p = 0.02). IL-6 and d-dimer levels were also higher in cases compared to controls, though differences were not statistically significant (p-value 0.06 and 0.10, respectively).
Conclusions: In patients with cART-treated HIV infection, higher levels of systemic inflammatory markers were associated with increased bacterial pneumonia risk, while two pulmonary-specific inflammatory biomarkers, CC16 and SP-D, were not associated with bacterial pneumonia risk.
Dieulafoy's lesion (DL) is a rare source of gastrointestinal tract bleeding that may occur at any site in the gastrointestinal tract and may be difficult to detect by endoscopy. DL is characterized by a large, tortuous arteriole in the submucosa. This is a case of duodenal DL that is detected and treated by endoscopy. This article is part of an expert video encyclopedia.
Type 1 diabetes (T1D) results from the autoimmune destruction of insulin-producing beta-cells in the pancreas. Recruitment of inflammatory cells is prerequisite to beta-cell-injury. The junctional adhesion molecule (JAM) family proteins JAM-B and JAM–C are involved in polarized leukocyte transendothelial migration and are expressed by vascular endothelial cells of peripheral tissue and high endothelial venules in lympoid organs. Blocking of JAM-C efficiently attenuated cerulean-induced pancreatitis, rheumatoid arthritis or inflammation induced by ischemia and reperfusion in mice. In order to investigate the influence of JAM-C on trafficking and transmigration of antigen-specific, autoaggressive T-cells, we used transgenic mice that express a protein of the lymphocytic choriomeningitis virus (LCMV) as a target autoantigen in the β-cells of the islets of Langerhans under the rat insulin promoter (RIP). Such RIP-LCMV mice turn diabetic after infection with LCMV. We found that upon LCMV-infection JAM-C protein was upregulated around the islets in RIP-LCMV mice. JAM-C expression correlated with islet infiltration and functional beta-cell impairment. Blockade with a neutralizing anti-JAM-C antibody reduced the T1D incidence. However, JAM-C overexpression on endothelial cells did not accelerate diabetes in the RIP-LCMV model. In summary, our data suggest that JAM-C might be involved in the final steps of trafficking and transmigration of antigen-specific autoaggressive T-cells to the islets of Langerhans.
Blood levels of Glial Fibrillary Acidic Protein (GFAP) in patients with neurological diseases
(2013)
Background and Purpose: The brain-specific astroglial protein GFAP is a blood biomarker candidate indicative of intracerebral hemorrhage in patients with symptoms suspicious of acute stroke. Comparably little, however, is known about GFAP release in other neurological disorders. In order to identify potential “specificity gaps” of a future GFAP test used to diagnose intracerebral hemorrhage, we measured GFAP in the blood of a large and rather unselected collective of patients with neurological diseases.
Methods: Within a one-year period, we randomly selected in-patients of our university hospital for study inclusion. Patients with ischemic stroke, transient ischemic attack and intracerebral hemorrhage were excluded. Primary endpoint was the ICD-10 coded diagnosis reached at discharge. During hospital stay, blood was collected, and GFAP plasma levels were determined using an advanced prototype immunoassay at Roche Diagnostics.
Results: A total of 331 patients were included, covering a broad spectrum of neurological diseases. GFAP levels were low in the vast majority of patients, with 98.5% of cases lying below the cut-off that was previously defined for the differentiation of intracerebral hemorrhage and ischemic stroke. No diagnosis or group of diagnoses was identified that showed consistently increased GFAP values. No association with age and sex was found.
Conclusion: Most acute and chronic neurological diseases, including typical stroke mimics, are not associated with detectable GFAP levels in the bloodstream. Our findings underline the hypothesis that rapid astroglial destruction as in acute intracerebral hemorrhage is mandatory for GFAP increase. A future GFAP blood test applied to identify patients with intracerebral hemorrhage is likely to have a high specificity.
Body Integrity Identity Disorder (BIID) ist eine bisher kaum erforschte Störung, bei der die Betroffenen den Wunsch beziehungsweise das Verlangen nach einer Körperbehinderung verspüren. In den meisten Fällen, wie auch in dieser Studie, ist eine Oberschenkelamputation die gewünschte Modifikation. Durch die Amputation erhoffen die Betroffenen endlich sie selbst zu werden, da sie sich mit ihrem realen Körperbild nicht identifizieren können. Ihr vorgestelltes Körperbild ist das eines Amputierten. Die Störung manifestiert sich bereits im Kindesalter. Im Laufe der Zeit nimmt das Verlangen der Amputation zu, so dass es neben der vermehrten Beschäftigung sogar zu lebensgefährlichen Selbstverletzungen im Zuge einer Verwirklichung kommen kann.
Die vorliegende Studie beschäftigt sich erstmalig mittels funktioneller Magnetresonanztomographie mit der neuronalen Repräsentation der Störung BIID beim Anblick des eigenen realen und des gewünschten amputierten Körpers. Für die Studie wurden Fotos von den Probanden und einer fremden Person gemacht und mit einer Software so modifiziert, dass die Probanden in sechs verschiedenen Kategorien sowohl sich selbst real, sowie amputiert und mit Prothese als auch die fremde Person real, amputiert und mit Prothese gezeigt bekamen. Dasselbe Design wurde auch einer gesunden Kontrollgruppe vorgeführt. Aufgrund der Datenmenge wird in dieser Studie nur der reale und der amputierte Körper berücksichtigt.
Es zeigen sich deutliche Aktivierungsunterschiede zwischen der BIID Gruppe und der Kontrollgruppe beim Anblick des eigenen realen Körpers und beim Anblick des eigenen amputierten Körpers. Beim Anblick des eigenen realen Körpers zeigt die Kontrollgruppe gegenüber der BIID Gruppe einen stärkeren Selbstbezug zu ihrem Körper durch Aktivierungen des medialen frontalen Gyrus, des postzentralen Gyrus oder der Amygdala und einen positiver valenzierten Anblick, der sich im Gruppenvergleich durch eine Mehraktivierung im superioren temporalen Gyrus ausdrückt sowie durch die Ergebnisse der post-fMRT-Fragebögen unterstützt wird. Beim Anblick des eigenen amputierten Körpers zeigt sich durch ein fronto-parietales Netzwerk der stärkere Selbstbezug bei der BIID Gruppe. Die deutliche emotionale Involviertheit wird repräsentiert durch große Teile des limbischen Systems sowie durch präfrontale Bereiche. Hinzu kommen Aktivierungen, die eine deutliche Beteiligung des episodisch-autobiographischen und prozeduralen Gedächtnisses zeigen. So ist eine vollständig geplante Bewegungsabfolge der BIID Probanden beim Anblick ihres amputierten Körpers anhand der aktivierten Areale darstellbar, einschließlich der Feinregulationen in den Basalganglien, dem Nucleus ruber und dem Kleinhirn.
Die Ergebnisse zeigen neuronale Netzwerke der Körperrepräsentation, bei denen fehlende Aktivierungen der BIID Probanden beim Anblick des eigenen realen Körpers auf eine Fehlfunktion hindeuten könnten. Sie zeigen aber auch ein Netzwerk aus Erinnerungen und erlernten Prozessen, die mit Hilfe des mesolimbischen Dopaminsystems zur Aufrechterhaltung der Störung beitragen könnten. Zusammengefasst lässt sich sagen, dass das amputierte Wunschkörperbild neuronal stark und breitgefächert verankert ist und viel dominanter repräsentiert ist als das reale Körperbild. Durch die dargestellten Aktivierungen und Regelkreise leiten sich vor allem neue therapeutische Ansätze ab, die zu einer Linderung der Symptome von BIID beitragen könnten und vielleicht auch neue Anstöße in Hinblick auf eine Heilung der Störung liefern.
Spirochetes belonging to the Borrelia (B.) burgdorferi sensu lato complex differ in their resistance to complement-mediated killing, particularly in regard to human serum. In the present study, we elucidate the serum and complement susceptibility of B. valaisiana, a genospecies with the potential to cause Lyme disease in Europe as well as in Asia. Among the investigated isolates, growth of ZWU3 Ny3 was not affected while growth of VS116 and Bv9 was strongly inhibited in the presence of 50% human serum. Analyzing complement activation, complement components C3, C4 and C6 were deposited on the surface of isolates VS116 and Bv9, and similarly the membrane attack complex was formed on their surface. In contrast, no surface-deposited components and no aberrations in cell morphology were detected for serum-resistant ZWU3 Ny3. While further investigating the protective role of bound complement regulators in mediating complement resistance, we discovered that none of the B. valaisiana isolates analyzed bound complement regulators Factor H, Factor H-like protein 1, C4b binding protein or C1 esterase inhibitor. In addition, B. valaisiana also lacked intrinsic proteolytic activity to degrade complement components C3, C3b, C4, C4b, and C5. Taken together, these findings suggest that certain B. valaisiana isolates differ in their capability to resist complement-mediating killing by human serum. The molecular mechanism utilized by B. valaisiana to inhibit bacteriolysis appears not to involve binding of the key host complement regulators of the alternative, classical, and lectin pathways as already known for serum-resistant Lyme disease or relapsing fever borreliae.
Inhibition of the proteasome is considered as a promising strategy to sensitize cancer cells to apoptosis. Recently, we demonstrated that the proteasome inhibitor Bortezomib primes neuroblastoma cells to TRAIL-induced apoptosis. In the present study, we investigated whether Bortezomib increases chemosensitivity of neuroblastoma cells. Unexpectedly, we discover an antagonistic interaction of Bortezomib and microtubule-interfering drugs. Bortezomib significantly attenuates the loss of cell viability and induction of apoptosis on treatment with Taxol and different vinca alkaloids but not with other chemotherapeutics, that is, Doxorubicin and Cisplatinum. Importantly, Bortezomib inhibits G2/M transition by inhibiting proteasomal degradation of cell cycle regulatory proteins such as p21, thereby preventing cells to enter mitosis, the cell cycle phase in which they are most vulnerable to antitubulin chemotherapeutics. Consequently, Bortezomib counteracts Taxol-induced mitotic arrest and polyploidy, as shown by reduced expression of PLK1 and phosphorylated histone H3. In addition, Bortezomib antagonizes Taxol-mediated degradation of MCL-1 during mitotic arrest by preventing cells to enter mitosis and by inhibiting the proteasome. Downregulation of MCL-1 is critically required for Taxol-induced apoptosis, as overexpression of a phosphomutant MCL-1 variant, which is resistant to degradation, significantly diminishes Taxol-triggered apoptosis. Vice versa, attenuation of Bortezomib-mediated accumulation of MCL-1 by knockdown of MCL-1 significantly enhances Taxol/Bortezomib-induced apoptosis. Thus, Bortezomib rescues Taxol-induced apoptosis by inhibiting G2/M transition and mitigating MCL-1 degradation. The identification of this antagonistic interaction of Bortezomib and microtubule-targeted drugs has important implications for the design of Bortezomib-based combination therapies.
ß1-integrins are essential for angiogenesis but the mechanisms regulating integrin function in endothelial cells (EC) and their contribution to angiogenesis remain elusive. BRAG2 is a guanine nucleotide exchange factor for the small Arf-GTPases Arf5 and Arf6. The role of BRAG2 in EC and angiogenesis and the underlying molecular mechanisms remains unclear. siRNA-mediated BRAG2-silencing reduced EC angiogenic sprouting and migration. BRAG2-siRNA-transfection differentially affected a5ß1- and aVß3-integrin function: specifically, BRAG2-silencing increased focal/fibrillar adhesions and EC adhesion on ß1-integrin-ligands (fibronectin and collagen), while reducing the adhesion on the aVß3-integrin-ligand, vitronectin. Consistent with these results, BRAG2-silencing enhanced surface expression of a5ß1-integrin, while reducing surface expression of aVß3-integrin. Mechanistically, BRAG2 mediated recycling of aVß3-integrins and endocytosis of ß1-integrins and specifically of the active/matrix bound a5ß1-integrin present in fibrillar/focal adhesions (FA), suggesting that BRAG2 contributes to the disassembly of FA via ß1-integrin-endocytosis. Arf5 and Arf6 are promoting downstream of BRAG2 angiogenic sprouting, ß1-integrin-endocytosis and the regulation of FA. In vivo silencing of the BRAG2-orthologues in zebrafish embryos using morpholinos perturbed vascular development. Furthermore, in vivo intravitral injection of plasmids containing BRAG2-shRNA reduced pathological ischemia-induced retinal and choroidal neovascularization. These data reveals that BRAG2 is essential for developmental and pathological angiogenesis by promoting EC sprouting through regulation of adhesion by mediating ß1-integrin internalization and associates for the first time the process of ß1-integrin endocytosis with angiogenesis.
Vascular endothelial growth factors (VEGFs), initially thought to act specifically on the vascular system, exert trophic effects on neural cells during development and adulthood. Therefore, the VEGF system serves as a promising therapeutic target for brain pathologies, but its simultaneous action on vascular cells paves the way for harmful side effects. To circumvent these deleterious effects, many studies have aimed to clarify whether VEGFs directly affect neural cells or if the effects are mediated secondarily via other cell types, like vascular cells. A great number of reports have shown the expression and function of VEGF receptors (VEGFRs), mainly VEGFR-1 and -2, in neural cells, where VEGFR-2 has been described as the major mediator of VEGF-A signals. This review aims to summarize and compare the divergent roles of VEGFR-1 and -2 during CNS development and homeostasis.
The neurophysiological changes associated with Alzheimer's Disease (AD) and Mild Cognitive Impairment (MCI) include an increase in low frequency activity, as measured with electroencephalography or magnetoencephalography (MEG). A relevant property of spectral measures is the alpha peak, which corresponds to the dominant alpha rhythm. Here we studied the spatial distribution of MEG resting state alpha peak frequency and amplitude values in a sample of 27 MCI patients and 24 age-matched healthy controls. Power spectra were reconstructed in source space with linearly constrained minimum variance beamformer. Then, 88 Regions of Interest (ROIs) were defined and an alpha peak per ROI and subject was identified. Statistical analyses were performed at every ROI, accounting for age, sex and educational level. Peak frequency was significantly decreased (p < 0.05) in MCIs in many posterior ROIs. The average peak frequency over all ROIs was 9.68 ± 0.71 Hz for controls and 9.05 ± 0.90 Hz for MCIs and the average normalized amplitude was (2.57 ± 0.59)·10(-2) for controls and (2.70 ± 0.49)·10(-2) for MCIs. Age and gender were also found to play a role in the alpha peak, since its frequency was higher in females than in males in posterior ROIs and correlated negatively with age in frontal ROIs. Furthermore, we examined the dependence of peak parameters with hippocampal volume, which is a commonly used marker of early structural AD-related damage. Peak frequency was positively correlated with hippocampal volume in many posterior ROIs. Overall, these findings indicate a pathological alpha slowing in MCI.
Celiac disease (CD) is an immune-mediated enteropathy that is characterized by intraepithelial lymphocytosis, crypt hyperplasia, and villous atrophy. Prevalence is high and has been estimated to range between 0.5% and 1.5%. Capsule endoscopy (CE) has a sensitivity and specificity of approximately 90%. CD is an important differential diagnosis for diagnostic workup for anemia, malabsorption, or diarrhea, and must be recognized reliably by the investigator. Moreover, CE is the preferred method to screen for complications in CD, such as enteropathy-associated T-cell lymphoma, ulcerative jejunitis, and small bowel adenocarcinoma. This article is part of an expert video encyclopedia.
Aim: To evaluate the effectiveness of two different strategies using radiofrequency catheter ablation for redo procedures after cryoablation of atrial fibrillation.
Methods: Thirty patients (paroxysmal atrial fibrillation: 22 patients, persistent atrial fibrillation: 8 patients) had to undergo a redo procedure after initially successful circumferential pulmonary vein (PV) isolation with the cryoballoon technique (Arctic Front Balloon, CryoCath Technologies/Medtronic). The redo ablation procedures were performed using a segmental approach or a circumferential ablation strategy (CARTO; Biosense Webster) depending on the intra-procedural findings. After discharge, patients were scheduled for repeated visits at the arrhythmia clinic. A 7-day Holter monitoring was performed at 3, 12 and 24 mo after the ablation procedure.
Results: During the redo procedure, a mean number of 2.9 re-conducting pulmonary veins (SD ± 1.0 PVs) were detected (using a circular mapping catheter). In 20 patients, a segmental approach was sufficient to eliminate the residual pulmonary vein conduction because there were only a few recovered pulmonary vein fibres. In the remaining 10 patients, a circumferential ablation strategy was used because of a complete recovery of the PV-LA conduction. All recovered pulmonary veins could be isolated successfully again. At 2-year follow-up, 73.3% of all patients were free from an arrhythmia recurrence (22/30). There were no major complications.
Conclusion: In patients with an initial circumferential pulmonary vein isolation using the cryoballoon technique, a repeat ablation procedure can be performed safely and effectively using radiofrequency catheter ablation.
B lymphocytes are an important cell population of the immune system. However, until recently it was not possible to transduce resting B lymphocytes with retro- or lentiviral vectors, making them unsusceptible for genetic manipulations by these vectors. Lately, we demonstrated that lentiviral vectors pseudotyped with modified measles virus (MV) glycoproteins hemagglutinin, responsible for receptor recognition, and fusion protein were able to overcome this transduction block. They use either the natural MV receptors, CD46 and signaling lymphocyte activation molecule (SLAM), for cell entry (MV-LV) or the vector particles were further modified to selectively enter via the CD20 molecule, which is exclusively expressed on B lymphocytes (CD20-LV). It has been shown previously that transduction by MV-LV does not induce B lymphocyte activation. However, if this is also true for CD20-LV is still unknown. Here, we generated a vector specific for another B lymphocyte marker, CD19, and compared its ability to transduce resting B lymphocytes with CD20-LV. The vector (CD19ds-LV) was able to stably transduce unstimulated B lymphocytes, albeit with a reduced efficiency of about 10% compared to CD20-LV, which transduced about 30% of the cells. Since CD20 as well as CD19 are closely linked to the B lymphocyte activation pathway, we investigated if engagement of CD20 or CD19 molecules by the vector particles induces activating stimuli in resting B lymphocytes. Although, activation of B lymphocytes often involves calcium influx, we did not detect elevated calcium levels. However, the activation marker CD71 was substantially up-regulated upon CD20-LV transduction and most importantly, B lymphocytes transduced with CD20-LV or CD19ds-LV entered the G1b phase of cell cycle, whereas untransduced or MV-LV transduced B lymphocytes remained in G0. Hence, CD20 and CD19 targeting vectors induce activating stimuli in resting B lymphocytes, which most likely renders them susceptible for lentiviral vector transduction.
CD69 is a transmembrane lectin that can be expressed on most hematopoietic cells. In monocytes, it has been functionally linked to the 5-lipoxygenase pathway in which the leukotrienes, a class of highly potent inflammatory mediators, are produced. However, regarding CD69 gene expression and its regulatory mechanisms in monocytes, only scarce data are available. Here, we report that CD69 mRNA expression, analogous to that of 5-lipoxygenase, is induced by the physiologic stimuli transforming growth factor-β (TGF-β) and 1α,25-dihydroxyvitamin D3 (1α,25(OH)2D3) in monocytic cells. Comparison with T- and B-cell lines showed that the effect was specific for monocytes. CD69 expression levels were increased in a concentration-dependent manner, and kinetic analysis revealed a rapid onset of mRNA expression, indicating that CD69 is a primary TGF-β/1α,25(OH)2D3 target gene. PCR analysis of different regions of the CD69 mRNA revealed that de novo transcription was initiated and proximal and distal parts were induced concomitantly. In common with 5-lipoxygenase, no activation of 0.7 kb or ~2.3 kb promoter fragments by TGF-β and 1α,25(OH)2D3 could be observed in transient reporter assays for CD69. Analysis of mRNA stability using a transcription inhibitor and a 3′UTR reporter construct showed that TGF-β and 1α,25(OH)2D3 do not influence CD69 mRNA stability. Functional knockdown of Smad3 clearly demonstrated that upregulation of CD69 mRNA, in contrast to 5-LO, depends on Smad3. Comparative studies with different inhibitors for mitogen activated protein kinases (MAPKs) revealed that MAPK signalling is involved in CD69 gene regulation, whereas 5-lipoxygenase gene expression was only partly affected. Mechanistically, we found evidence that CD69 gene upregulation depends on TAK1-mediated p38 activation. In summary, our data indicate that CD69 gene expression, conforming with 5-lipoxygenase, is regulated monocyte-specifically by the physiologic stimuli TGF-β and 1α,25(OH)2D3 on mRNA level, although different mechanisms account for the upregulation of each gene.
Introduction: Postural control is a prerequisite to many everyday and sporting activities which requires the interaction of multiple sensorimotor processes. As long as we have no balance disorders, the maintenance of an erect standing position is taken for granted with automatic running control processes. It is well known that with increasing age or disease balance problems occur which often cause fall-related injuries. To assess balance performance, posturography is widely applied in which body sway is traditionally viewed as a manifestation of random fluctuations. Thus, the amount of sway is solely used as an index of postural stability, that is, less sway is an indication of better control. But, traditional measures of variability fail to account for the temporal organisation of postural sway. The concept of nonlinear dynamics suggests that variability in the motor output is not random but structured. It provides the stimulus to reveal the functionality of postural sway. This thesis evaluates nonlinear analysis tools in addition to classic linear methods in terms of age-related modifications of postural control and under different standing conditions in order to broaden the existing knowledge of postural control processes.
Methods: Static posturographic analyses were conducted which included the recording of centre of pressure (COP) time series by means of a force plate. Linear and nonlinear methods were used to quantify postural sway variability in order to evaluate both the amount and structure of sway. Classic time and frequency domain COP parameters were computed. In addition, wavelet transform (WT), multiscale entropy, detrended fluctuation analysis, and scaled windowed variance method were applied to COP signals in order to derive structural COP parameters. Two experiments were performed. 1) 16 young (26.1 ± 6.7 years), healthy subjects were asked to adopt a bipedal stance under single- and dual-task conditions. Three trials were conduced each with a different sampling duration: 30, 60, and 300 seconds [s]. 2) 26 young (28.15 ± 5.86 years) and 13 elderly (72 ± 7 years) subjects stood quietly for 60 s on five different surfaces which imposed different biomechanical constraints: level ground (LG), one foot on a step (ST), uphill (UH), downhill (DH), and slope (SL). Additional to COP recordings, limb load symmetry was assessed via foot pressure insoles.
Results: We found a higher sensitivity of structural COP parameters to modulations of postural control and partly an improved evaluation of sway dynamics in longer COP recordings. WT revealed a reweighing of frequency bands in response to altered standing conditions. Scaling exponents and entropy values of COP signals were task-dependent. Higher entropy values were found under the dual-task and condition ST. The time scales affected under the altered standing positions differed between groups and sway directions. Mainly larger posturograms were found in the elderly. Age effects were especially revealed in position ST and concerning medial-lateral COP signals. Load asymmetry was stronger in elderly subjects for LG, UH, and DH positions.
Discussion: Modifications of multiple time scales corresponds to an interplay of control subsystems to cope with the altered task demands. The affected time scales are age-dependent suggesting a change of control processes. Higher irregularity under the dual-task indicates a more complex motor output which is interpreted as less attentional investment into postural control. Larger complexity is evident for ST in contrast to LG position. ST obviously challenges lateral sway which is counteracted differently between groups. Load asymmetry suggests that especially elderly subjects adopt a step-initiation strategy.
Conclusion: A continued application of nonlinear methods is necessary to broaden the understanding of postural control mechanisms and to identify classifiers for balance dysfunctions. Structural COP parameters provide a more comprehensive indication of postural control system properties between groups and task demands. COP recordings of at least 60 s are recommended to adequately quantify COP signal structure. The analysis of postural strategies in everyday activities increases the ecological validity of postural control studies and can provide valuable information regarding the development of effective rehabilitation programs.
Eine Infektion mit dem Hepatitis B Virus (HBV) kann bei 5-10 % der infizierten Erwachsenen und 70-90 % der infizierten Kinder chronisch verlaufen. Trotz einer verfügbaren Impfung gegen die Erkrankung sind heute nach Angaben der WHO weltweit etwa 350 Mio. Menschen chronisch HBV-infiziert [Lupberger and Hildt, 2007, Hollinger and Liang, 2001]. In 5-10 % der Fälle führt eine chronische Infektion zu einer Leberfibrose und Zirrhose, welche letztlich zur Ausbildung eines hepatozellulären Karzinoms (HCC) führen kann. HCCs sind die dritthäufigste karzinomassoziierte Todesursache weltweit [Blum, 2005]. Um Therapien gegen eine HBV-Infektion und das damit erhöhte Risiko einer HCC-Entstehung entwickeln zu können, müssen die einzelnen Schritte des HBV-Replikationszyklus verstanden sein. Wesentliche Schritte der frühen Infektionsphase, insbesondere der Rezeptor bzw. Rezeptorkomplex, welcher den Zelleintritt des Virus vermittelt sowie der Transport des Virusgenoms in den Zellkern, sind bisher noch unklar. Auch der Exportprozess und die Freisetzung der Viruspartikel ist bisher noch nicht im Detail verstanden. Es ist jedoch bekannt, dass die Viruspartikel unter Nutzung der zellulären ESCRT (endosomal sorting complex required for transport)-Maschinerie aus der Zelle freigesetzt werden [Lambert et al., 2007]. Auf der Suche nach Faktoren, die in diese Vorgänge involviert sind, konnte in dieser Arbeit das vesikeltransportassoziierte Protein α-Taxilin identifiziert werden. Der Einfluss von HBV auf die α-Taxilin-Bildung und seine mögliche Beteiligung am viralen Export wurden dabei näher charakterisiert. In HBV-positiven Zellen konnte in vivo und in vitro eine signifikante Steigerung der α-Taxilin-Expression nachgewiesen werden. Diese wird hierbei durch die HBV-Proteine HBx und LHBs über den Raf/Mek/Erk-Signalweg induziert [Glatzel, 2011]. Mithilfe von knockdown-Experimenten konnte beobachtet werden, dass α-Taxilin für den Export der Viruspartikel, nicht aber für den Export subviraler Partikel (SVPs) essentiell ist. Der Export der Virionen findet hierbei über das ESCRT-System statt. Den HBV-Strukturproteinen fehlen jedoch die für die Interaktion mit dem ESCRT-System essentiellen late-Domänen. Die Proteinstruktur von α-Taxilin dagegen weist diese late-Domänen auf. In dieser Arbeit konnte diese interaktionsvermittelnde Funktion von α-Taxilin zwischen dem Virus und dem ESCRT-System charakterisiert werden. Über eine Interaktion von α-Taxilin mit dem viralen LHBs-Protein auf der einen Seite und der tsg101-Komponente des ESCRT-I-Komplexes auf der anderen Seite agiert α-Taxilin als eine Art Linker zwischen dem ESCRT-System und HBV.
Darüber hinaus wurde Annexin A5 als zellulärer Interaktionspartner für α-Taxilin identifiziert [Röttger, 2011]. Es dirigiert α-Taxilin in einer Art shuttle-Funktion auf die Zellmembran suszeptibler Zellen und bindet es an deren Zelloberfläche. Diese Exposition von α-Taxilin nimmt während der Dedifferenzierung in Korrelation mit dem Suszeptibilitätsverlust primärer Hepatozyten ab. Eine Maskierung von α-Taxilin durch eine vorherige Inkubation der Zellen mit α-Taxilin-spezifischen Antikörpern konnte die Bindung und die Aufnahme der Viren inhibieren. Überexpressionsstudien bestätigten die essentielle Rezeptorfunktion von α-Taxilin. Die verstärkte Produktion von α-Taxilin führte zur Suszeptibilität der Zellen. Auch die Speziesspezifität der Bindung zwischen humanem α-Taxilin und HBV konnte in einem Co-Immunpräzipitationsexperiment mit den rezeptorbindenden Domänen von HBV, WHV und DHBV identifiziert werden.
In der vorliegenden Arbeit konnte somit zum ersten Mal eine Rezeptorfunktion von α-Taxilin bei der Aufnahme von HBV in die Wirtszelle nachgewiesen werden. Darüber hinaus schreiben die in dieser Arbeit gemachten Beobachtungen α-Taxilin eine essentielle Funktion für die Vermittlung des ESCRT-abhängigen Exports der Virionen aus der Zelle zu. Die hierbei gewonnen Erkenntnisse sind von hoher Relevanz für die weitere Erforschung der HBV-assoziierten Pathogenese und die Etablierung eines in vivo Infektions-Modells.
Purpose. Chemotherapy-induced peripheral neuropathy (CIPN) is a common and dose-limiting side effect of cytostatic drugs. Since there are no proven therapeutic procedures against CIPN, we were interested to define the role of electroacupuncture (EA) from which preliminary data showed promising results. Methods. In a randomized trial with a group sequential adaptive design in patients with CIPN, we compared EA (LV3, SP9, GB41, GB34, LI4, LI11, SI3, and HT3; n=14) with hydroelectric baths (HB, n=14), vitamin B1/B6 capsules (300/300 mg daily; VitB, n=15), and placebo capsules (n=17). The statistical power in this trial was primarily calculated for proving EA only, so results of HB and VitB are pilot data. Results. CIPN complaints improved by 0.8 +- 1.2 (EA), 1.7 +- 1.7 (HB), 1.6 +- 2.0 (VitB), and 1.3 +- 1.3 points (placebo) on a 10-point numeric rating scale without significant difference between treatment groups or placebo. In addition no significant differences in sensory nerve conduction studies or quality of life (EORTC QLQ-C30) were found. Conclusions. The used EA concept, HB, and VitB were not superior to placebo. Since, contrary to our results, studies with different acupuncture concepts showed a positive effect on CIPN, the effect of acupuncture on CIPN remains unclear. Further randomized, placebo controlled studies seem necessary. This trial is registered with DRKS00004448.
Persistent infections with hepatitis C virus (HCV) may result in life-threatening liver disease, including cirrhosis and cancer, and impose an important burden on human health. Understanding how the virus is capable of achieving persistence in the majority of those infected is thus an important goal. Although HCV has evolved multiple mechanisms to disrupt and block cellular signaling pathways involved in the induction of interferon (IFN) responses, IFN-stimulated gene (ISG) expression is typically prominent in the HCV-infected liver. Here, we show that Toll-like receptor 3 (TLR3) expressed within uninfected hepatocytes is capable of sensing infection in adjacent cells, initiating a local antiviral response that partially restricts HCV replication. We demonstrate that this is dependent upon the expression of class A scavenger receptor type 1 (MSR1). MSR1 binds extracellular dsRNA, mediating its endocytosis and transport toward the endosome where it is engaged by TLR3, thereby triggering IFN responses in both infected and uninfected cells. RNAi-mediated knockdown of MSR1 expression blocks TLR3 sensing of HCV in infected hepatocyte cultures, leading to increased cellular permissiveness to virus infection. Exogenous expression of Myc-MSR1 restores TLR3 signaling in MSR1-depleted cells with subsequent induction of an antiviral state. A series of conserved basic residues within the carboxy-terminus of the collagen superfamily domain of MSR1 are required for binding and transport of dsRNA, and likely facilitate acidification-dependent release of dsRNA at the site of TLR3 expression in the endosome. Our findings reveal MSR1 to be a critical component of a TLR3-mediated pattern recognition receptor response that exerts an antiviral state in both infected and uninfected hepatocytes, thereby limiting the impact of HCV proteins that disrupt IFN signaling in infected cells and restricting the spread of HCV within the liver.
Choriocarcinoma is the most malignant tumor of gestational trophoblastic disease arising from any gestation. It has a tendency toward relapse as well as metastasis. Here, a case of relapsed high-risk choriocarcinoma (FIGO stage IV, WHO score 12) in a 37-year-old female presenting with vaginal bleedings is described. Relapse developed at the site of the surgical scar from hysterectomy that had been performed 2 years earlier. Although the patient was treated with aggressive chemotherapy, she was in a bad general condition and died from infection and liver insufficiency.
The author presents the case of a patient with severe bleeding from a duodenal ulcer that could not be controlled by endoscopic application of metal clips and injection of fibrin glue. Angiographic embolization with placement of coils into the feeding vessel stopped the bleeding. However, 3 days later, a fistula emerged from coil material penetrating into the dorsal duodenum and a peritoneal leakage developed. The fistula was completely closed by placing an over-the-scope clip on the enteral opening of the fistula. This article is part of an expert video encyclopedia.
BACKGROUND: Systemic thrombolysis with recombinant tissue plasminogen activator (rt-PA) is the standard of acute stroke care. Its potential to increase the risk of secondary intracerebral hemorrhage, especially if administered late, has been ascribed to its proteolytic activity that has detrimental effects on blood-brain barrier (BBB) integrity after stroke. FTY720 has been shown to protect endothelial barriers in several disease models such as endotoxin-induced pulmonary edema and therefore is a promising candidate to counteract the deleterious effects of rt-PA. Besides that, every putative neuroprotectant that will be eventually forwarded into clinical trials should be tested in conjunction with rt-PA.
METHODS: We subjected C57Bl/6 mice to 3 h filament-induced tMCAO and postoperatively randomized them into four groups (n = 18/group) who received the following treatments directly prior to reperfusion: 1) vehicle-treatment, 2) FTY720 1 mg/kg i.p., 3) rt-PA 10 mg/kg i.v. or 4) FTY720 and rt-PA as a combination therapy. We measured functional neurological outcome, BBB disruption by quantification of EB extravasation and MMP-9 activity by gelatin zymography.
RESULTS: We observed a noticeable increase in mortality in the rt-PA/FTY720 cotreatment group (61%) as compared to the vehicle (33%), the FTY720 (39%) and the rt-PA group (44%). Overall, functional neurological outcome did not differ significantly between groups and FTY720 had no effect on rt-PA- and stroke-induced BBB disruption and MMP-9 activation.
CONCLUSIONS: Our data show that FTY720 does not improve functional outcome and BBB integrity in large hemispheric infarctions, neither alone nor in conjunction with rt-PA. These findings stand in contrast to a recently published study that showed beneficial effects of FTY720 in combination with thrombolysis in a thrombotic model of MCAO leading to circumscript cortical infarctions. They might therefore represent a caveat that the coadministration of these two drugs might lead to excess mortality in the setting of a severe stroke.
In the stomach, neoplastic lesions often arise in the setting of precursor conditions such as gastritis, intestinal metaplasia, or adenomatous lesions. Biopsies may, therefore, underestimate disease severity or even miss the diagnosis (sampling error). Endomicroscopy is able to visualize typical features of such pathologies. It enables in vivo microscopy of gastritis with definition of enhanced vascularity and vascular leakage, but the typical cobblestone appearance of the gastric mucosa is preserved. The presence of intestinal metaplasia is confirmed by columnar absorptive cells with brush border and goblet cells within villiform foveolar epithelium. Gastric neoplasia is characterized by crowded glands with intraluminal folding and glandular budding and branching accompanied by increased density of dilated and distorted capillaries. Finally, in gastric cancer, gland and overall mucosal architecture is progressively lost. These features are shown side by side with white-light endoscopic findings. Endomicroscopy is used in such a setting to rapidly screen larger areas (optical biopsies) and subsequently target tissue sampling to areas with highly suspicious microscopic patterns. In experienced hands, it therefore constitutes an important part especially in the presence of neoplastic lesions within noncircumscript gastric premalignant conditions. This article is part of an expert video encyclopedia.
Purpose: To correlate inflammatory and proangiogenic key cytokines from undiluted vitreous of treatment-naïve central retinal vein occlusion (CRVO) patients with SD-OCT parameters.
Methods: Thirty-five patients (age 71.1 years, 24 phakic, 30 nonischemic) underwent intravitreal combination therapy, including a single-site 23-gauge core vitrectomy. Twenty-eight samples from patients with idiopathic, non-uveitis floaterectomy served as controls. Interleukin 6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and vascular endothelial growth factor (VEGF-A) levels were correlated with the visual acuity (logMar), category of CRVO (ischemic or nonischemic) and morphologic parameters, such as central macular thickness-CMT, thickness of neurosensory retina-TNeuro, extent of serous retinal detachment-SRT and disintegrity of the IS/OS and others.
Results: The mean IL-6 was 64.7pg/ml (SD ± 115.8), MCP-1 1015.7 ( ± 970.1), and VEGF-A 278.4 ( ± 512.8), which was significantly higher than the control IL-6 6.2 ± 3.4pg/ml (P=0.06), MCP-1 253.2 ± 73.5 (P<0.0000001) and VEGF-A 7.0 ± 4.9 (P<0.0006). All cytokines correlated highly with one another (correlation coefficient r=0.82 for IL-6 and MCP-1; r=0.68 for Il-6 and VEGF-A; r=0.64 for MCP-1 and VEGF-A). IL-6 correlated significantly with CMT, TRT, SRT, dIS/OS, and dELM. MCP-1 correlated significantly with SRT, dIS/OS, and dELM. VEGF-A correlated not with changes in SD-OCT, while it had a trend to be higher in the ischemic versus the nonischemic CRVO group (P=0.09).
Conclusions: The inflammatory cytokines were more often correlated with morphologic changes assessed by SD-OCT, whereas VEGF-A did not correlate with CRVO-associated changes in SD-OCT. VEGF inhibition alone may not be sufficient in decreasing the inflammatory response in CRVO therapy.
Purpose: To assess the levels of inflammatory and angiogenic cytokines in undiluted vitreous from treatment-naïve patients with macular edema secondary to nonischemic branch retinal vein occlusion (BRVO), with flow cytometric bead array (CBA) and to correlate the results with subjective and multiple spectral-domain optical coherence tomography (SD-OCT) parameters.
Methods: A total of 43 eyes from 43 patients (mean age 69.7 years, 23 male) were divided into groups of new, "fresh" (n = 28; mean duration after onset 4.1 months) and older BRVO (n = 15; 11.6 months). Because of macular edema, these patients underwent an intravitreal therapy combining a single-site 23 g core vitrectomy with bevacizumab and dexamethasone. Undiluted vitreous was then analyzed for interleukin-6 (IL-6), monocyte chemoattractant protein-1 (MCP-1), and vascular endothelial growth factor isoform A (VEGF-A) levels with CBA and correlated with visual acuity (VA), clinical parameters of BRVO (type and perfusion status), and morphologic parameters, such as central macular thickness, central retinal thickness, thickness of the neurosensory retina, thickness of the serous retinal detachment, and the disruption of the ellipsoid line (photoreceptor inner and outer segments) and the external limiting membrane, as measured with SD-OCT. Twenty-eight undiluted vitreous samples from patients with idiopathic, nonuveitis vitreous floaters served as the controls.
Results: The mean IL-6 was 23.2 pg/mL (standard deviation, ±48.8), MCP-1 was 602.6 (±490.3), and VEGF-A was 161.8 (±314.3), and this was higher than in the control group, which had a mean IL-6 of 6.2 ± 3.4 pg/mL (P = 0.17), MCP-1 of 253.2 ± 73.5 (P < 0.0000001), and VEGF-A of 7.0 ± 4.9 (P < 0.003). In all BRVO samples, IL-6 correlated positively with MCP-1 and VEGF-A (correlation coefficient r = 0.79 and r = 0.46, respectively). VEGF-A was the only cytokine to correlate significantly with SD-OCT parameters (thickness of the neurosensory retina r = 0.31; disruption of the ellipsoid line r = 0.33). In the older BRVO group, there was a positive correlation between cytokines (IL-6 with MCP-1, r = 0.77; Il-6 with VEGF-A, r = 0.68; MCP-1 and VEGF-A, r = 0.68), whereas only IL-6 correlated with MCP-1 in the fresh group (r = 0.8).
Conclusion: The inflammatory markers and VEGF-A were elevated in the vitreous fluid of patients with BRVO, and these correlated with one another. VEGF-A was more often correlated with the morphologic changes assessed by SD-OCT, whereas the inflammatory markers had no significant influence on SD-OCT changes.
The study objective was to assess the current status of HIV knowledge, attitudes and behavior (KAB) among employees of Namibian ministries. As most HIV campaigning takes place in the capital of Windhoek, an additional aim was to compare Windhoek to four regions (Hardap, Erongo, Oshana, and Caprivi). Between January and March 2011 a cross-sectional survey was conducted in two Namibian ministries, with participants selected randomly from the workforce. Data collection was based on questionnaires. 832 participants were included in the study (51.6% male). Nearly 90% of participants reported to have been tested for HIV before. Knowledge about HIV transmission ranged from 67% to 95% of correct answers, with few differences between the capital and regions. However, a knowledge gap regarding HIV transmission and prevention was seen. In particular, we found significantly lower knowledge regarding transmission from mother-to-child during pregnancy and higher rate of belief in a supernatural role in HIV transmission. In addition, despite many years of HIV prevention activities, a substantial proportion of employees had well-known HIV risk factors including multiple concurrent partnership rates (21%), intergenerational sex (19%), and lower testing rates for men (82% compared to women with 91%).
CSF and serum biomarkers focusing on cerebral vasospasm and ischemia after subarachnoid hemorrhage
(2013)
Delayed cerebral vasospasm (CVS) and delayed cerebral ischemia (DCI) remain severe complications after subarachnoid hemorrhage (SAH). Although focal changes in cerebral metabolism indicating ischemia are detectable by microdialysis, routinely used biomarkers are missing. We therefore sought to evaluate a panel of possible global markers in serum and cerebrospinal fluid (CSF) of patients after SAH.
CSF and serum of SAH patients were analyzed retrospectively. In CSF, levels of inhibitory, excitatory, and structural amino acids were detected by high-performance liquid chromatography (HPLC). In serum, neuron-specific enolase (NSE) and S100B level were measured and examined in conjunction with CVS and DCI. CVS was detected by arteriography, and ischemic lesions were assessed by computed tomography (CT) scans.
All CSF amino acids were altered after SAH. CSF glutamate, glutamine, glycine, and histidine were significantly correlated with arteriographic CVS. CSF glutamate and serum S100B were significantly correlated with ischemic events after SAH; however, NSE did not correlate neither with ischemia nor with vasospasm. Glutamate, glutamine, glycine, and histidine might be used in CSF as markers for CVS. Glutamate also indicates ischemia. Serum S100B, but not NSE, is a suitable marker for ischemia. These results need to be validated in larger prospective cohorts.
Cytoprotective functions of amyloid precursor protein family members in stress signaling and aging
(2013)
Poster presentation: Molecular Neurodegeneration: Basic biology and disease pathways Cannes, France. 10-12 September 2013.
Background: The amyloid precursor protein (APP) is processed via two different metabolic pathways: the amyloidogenic and the non-amyloidogenic pathway, the latter of which leading to generation of the secreted N-terminal APP fragment sAPPα [1]. Previous studies from our group suggest that sAPPα exerts potent neuroprotective effects and inhibits stress-triggered cell death via modulation of gene expression, as well as by antagonizing different types of neurotoxic stress [2]. It was also observed that the biochemical processing of APP is downregulated during aging which in turn reduced the secretion of sAPPα [3]. Based on these observations, we have studied the potential physiological function of sAPPα/APP and APLPs (APP like proteins) on the regulation of age-associated, stress induced signaling pathways, apoptosis and senescence.
Materials and methods: SH-SY5Y, PC12, IMR90 cells were used as cellular models. Depletion of APP, APLP1 (APP like protein 1) and APLP2 (APP like protein 2) in SH-SY5Y cells was achieved by stable lentiviral knockdown. To analyze the protective function of sAPPα, we have used conditioned supernatants of wild type APP overexpressing HEK cells and recombinant His-tagged sAPPα purified from yeast. The cells were treated with sAPPα prior to the addition of different stress stimuli (MG132, epoxomicin, UV, H2O2) after which cell death, gene expression and senescence were analyzed by MTT assays, caspase activity assays, Western blots and X-Gal staining respectively.
Results: Our data show that sAPPα can antagonize premature senescence induced by repetitive short term induction of proteasomal stress in IMR-90 cells and apoptosis triggered by prolonged proteasomal stress and other death stimuli in PC12, SH-SY5Y and IMR90 cells which was accompanied by a sAPPα-dependent inhibition of the JNK stress signaling pathway. In contrast, no significant changes in cell viability and apoptosis were observed when APP knockdown cells were pretreated with sAPPα.
Conclusions: Our observations suggest that sAPPα can antagonize both apoptosis and cellular senescence and requires expression of holo-APP to mediate its cytoprotective effects. They also support the notion that the physiological function of APP is linked to modulation of neuronal and brain aging.
Current theories of the pathophysiology of schizophrenia have focused on abnormal temporal coordination of neural activity. Oscillations in the gamma-band range (>25 Hz) are of particular interest as they establish synchronization with great precision in local cortical networks. However, the contribution of high gamma (>60 Hz) oscillations toward the pathophysiology is less established. To address this issue, we recorded magnetoencephalographic (MEG) data from 16 medicated patients with chronic schizophrenia and 16 controls during the perception of Mooney faces. MEG data were analysed in the 25–150 Hz frequency range. Patients showed elevated reaction times and reduced detection rates during the perception of upright Mooney faces while responses to inverted stimuli were intact. Impaired processing of Mooney faces in schizophrenia patients was accompanied by a pronounced reduction in spectral power between 60–120 Hz (effect size: d = 1.26) which was correlated with disorganized symptoms (r = −0.72). Our findings demonstrate that deficits in high gamma-band oscillations as measured by MEG are a sensitive marker for aberrant cortical functioning in schizophrenia, suggesting an important aspect of the pathophysiology of the disorder.
Delayed wound repair in sepsis is associated with reduced local pro-inflammatory cytokine expression
(2013)
Sepsis is one of the main causes for morbidity and mortality in hospitalized patients. Moreover, sepsis associated complications involving impaired wound healing are common. Septic patients often require surgical interventions that in-turn may lead to further complications caused by impaired wound healing. We established a mouse model to the study delayed wound healing during sepsis distant to the septic focus point. For this reason cecal ligation and puncture (CLP) was combined with the creation of a superficial wound on the mouse ear. Control animals received the same procedure without CPL. Epithelialization was measured every second day by direct microscopic visualization up to complete closure of the wound. As interplay of TNF-α, TGF-β, matrix metalloproteinases (MMP), and tissue inhibitors of metalloproteinases (TIMP) is important in wound healing in general, TNF-α, TGF-β, MMP7, and TIMP1 were assessed immunohistochemical in samples of wounded ears harvested on days 2, 6, 10 and 16 after wounding. After induction of sepsis, animals showed a significant delay in wound epithelialization from day 2 to 12 compared to control animals. Complete wound healing was attained after mean 12.2± standard deviation (SD) 3.0 days in septic animals compared to 8.7± SD 1.7 days in the control group. Septic animals showed a significant reduction in local pro-inflammatory cytokine level of TNF-α on day 2 and day 6 as well as a reduced expression of TGF-β on day 2 in wounds. A significant lower expression of MMP7 as well as TIMP1 was also observed on day 2 after wounding. The induction of sepsis impairs wound healing distant to the septic focus point. We could demonstrate that expression of important cytokines for wound repair is deregulated after induction of sepsis. Thus restoring normal cytokine response locally in wounds could be a good strategy to enhance wound repair in sepsis.
Poster presentation: Twenty Second Annual Computational Neuroscience Meeting: CNS*2013. Paris, France. 13-18 July 2013.
Neuronal death and subsequent denervation of target areas is a major feature of several neurological conditions such as brain trauma, ischemia or neurodegeneration. The denervation-induced axonal loss results in reorganization of the dendritic tree of denervated neurons. Dendritic reorganization of denervated neurons has been previously studied using entorhinal cortex lesion (ECL).
ECL leads to shortening and loss of dendritic segments in the denervated outer molecular layer of the dentate gyrus [1]. However, the functional importance of these long-term dendritic alterations is not yet understood and their impact on neuronal electrical properties remains unclear. Therefore, in this study we analyzed what happens to the electrotonic structure and excitability of dentate granule cells after denervation-induced alterations of their dendritic morphology, assuming all other parameters remain equal.
To perform comparative electrotonic analysis we used computer simulations in anatomically and biophysically realistic compartmental models of 3D-reconstructed healthy and denervated granule cells. Our results show that somatofugal and somatopetal voltage attenuation due to passive cable properties was strongly reduced in denervated granule cells. In line with these predictions, the attenuation of simulated backpropagating action potentials and forward propagating EPSPs was significantly reduced in dendrites of denervated neurons. In addition, simulations of somatic and dendritic frequency-current (f-I) curves revealed increased excitability in deafferentated granule cells.
Taken together, our results indicate that unless counterbalanced by a compensatory adjustment of passive and/or active membrane properties, the plastic remodeling of dendrites following lesion of entorhinal cortex inputs to granule cells will boost their electrotonic compactness and excitability.
Background. Incomplete revascularization negatively affects survival after coronary artery bypass surgery (CABG). Since gender and classification technique might impact outcome and reporting, we investigated their effect on revascularization patterns and mortality. Methods. A cohort of bypass patients (N = 1545, 23% women) was enrolled prospectively. The degree of revascularization was determined as mathematical difference between affected vessels upon diagnosis and number of grafts or the surgeon’s rating on the case file. Results. Although men displayed more triple-vessel disease, they obtained complete revascularization more frequently than women (85% versus 77%, P < 0.001). The two calculation methods identified analogous percentages of incompletely revascularized patients, yet there was only a 50% overlap between the two groups. Mathematically, more women, older patients, and patients with NYHA class III/IV appeared incompletely revascularized, while the surgeons identified more patients undergoing technically challenging procedures. Regardless of the definition, incompleteness was a significant risk factor for mortality in both genders (mathematical calculation: HR 2.62, 95% CI 1.76–3.89, P < 0.001; surgeon: HR 2.04, 95% CI 1.35–3.89, P = 0.001). Conclusions. Given the differences in identification patterns, we advise that the mathematical calculation be performed after-procedure in all patients regardless of the surgeons’ rating to uncover additional subjects at increased risk.
Background: Published estimates on age-dependent frequency of diabetes in cystic fibrosis (CF) vary widely, and are based mostly on older data. However, CF treatment and prevention of comorbidities changed over recent years. In many studies, definition of cystic fibrosis-related diabetes (CFRD) is not in line with current guideline recommendations. Therefore, we evaluated age-dependent occurrence of glucose abnormalities and associated risk factors in CF patients who participated in a multicenter screening program using oral glucose tolerance tests (OGTT).
Methods: Between 2001 and 2010, 43 specialized CF centers from Germany and Austria serially performed 5,179 standardized OGTTs in 1,658 clinically stable, non-pregnant CF patients with no prior steroid medication or lung transplantation. Age-dependent occurrence of impaired fasting glucose (IFG), impaired glucose tolerance (IGT), IFG+IGT, one (DGT) or two consecutive (CFRD) diabetic OGTTs was analyzed, using Kaplan Meier curves. Cox proportional-hazards models were created to elucidate the influence of sex or underweight.
Results: At baseline/last OGTT, median age was 15.9 years/18.2 years and 30.6%/31.8% of patients were underweight. 25% of patients showed IFG at age 14.3 years; IGT at age 16.3 years; IFG+IGT combined at age 17.7 years. DGT was observed in 25% of patients at age 22.6 years; CFRD at age 34.5 years. Females had a 3.54 [95% CI 1.23–10.18] times higher risk for CFRD; risk for DGT was 2.21 [1.22–3.98] times higher. Underweight was a risk factor for IGT (HR [95% CI]: 1.38 [1.11–1.71]) and IFG+IGT (1.43 [1.11–1.83]), and in males also for DGT (1.49 [1.09–2.04]).
Conclusions/Significance: If confirmation of diabetes by a second test is required, as recommended in current guidelines, age at CFRD diagnosis was higher compared to most previous studies. However, known risk factors for glucose abnormalities in CF were confirmed. Confirmation of diabetic OGT by a repeat test is important for a consistent diagnosis of CFRD.
In der vorliegenden Arbeit konnte gezeigt werden, dass bestimmte neuronale microRNAs im Rückenmark und in den Spinalganglien konstitutiv exprimiert und nach peripherer Entzündung mit Formalin oder Zymosan differenziell reguliert werden. Bei der SNI-induzierten Neuropathie konnte indessen keine signifikante Regulation der untersuchten microRNAs nachgewiesen werden. Aufgrund der Lokalisation in den Neuronen der Schmerz-verarbeitenden Laminae I und II des Dorsalhorns des Rückenmarks und angesichts der Regulation in entzündlich stimulierten Neuronen und Mikroglia wurde der Fokus der Arbeit auf die Untersuchung von microRNA-124a gelegt. Anhand von Expressionsanalysen konnte gezeigt werden, dass eine periphere entzündliche Stimulation mit Formalin oder Zymosan microRNA-124a im Rückenmark inhibiert, die Expression pro-inflammatorischer und pro-nozizeptiver Gene hiernach ermöglicht und ein vermehrtes Schmerzverhalten bewirkt. Die funktionelle Relevanz von microRNA-124a wurde in vivo mittels intravenöser Applikation von microRNA-124a-Modulatoren bei einem Modell für entzündliche Schmerzen, dem Formalin-Modell untersucht. Dabei führte die Hemmung von microRNA-124a zu einem verstärkten Schmerzverhalten, welches mit einer Hochregulation verschiedener Entzündungsmarker einherging. Die Überexpression von microRNA-124a dagegen antagonisierte die Hochregulation entzündlicher Mediatoren und führte zu einer Schmerzhemmung. Darüber hinaus konnte in der vorliegenden Arbeit der antinozizeptive Effekt von microRNA-124a mit der Regulation der Epigenetik-regulierenden Targets MeCP2, HDAC5 und MYST2 assoziiert werden und u.a. über die Hemmung des neuromodulierenden, pro-inflammatorischen Peptids BDNF verifiziert werden. Die spezielle Darreichung von microRNA-124a könnte demzufolge einen vielversprechenden Ansatz zur Therapie chronisch-entzündlicher Schmerzen liefern. Zukünftig werden weitere Studien notwendig sein um die eindeutige Funktion, die individuelle Wirkung sowie die therapeutische Relevanz von microRNA-124a zu analysieren. Darüber hinaus müssten Dosis-Wirkungs-Beziehungen und Nebenwirkungsprofile für microRNA-124a erstellt werden, um potenzielle Risiken, Chancen und Vorteile der microRNA-Modulation hinsichtlich einer humanen Schmerztherapie bewerten zu können.
Rückschläge werfen eine neue Technologie um Jahrzehnte zurück – besonders, wenn Menschenleben zu beklagen sind. Bei der Gentherapie wird aber oft vergessen, dass sie nur bei Patienten angewendet wird, für die es keine konventionelle Therapie mehr gibt. Nach der Euphorie und den Rückschlägen der Anfangsjahre können Forscher nun die ersten Erfolge vorweisen.
Krebserkrankungen des lymphatischen Systems verlaufen sehr unterschiedlich, sind schwer zu diagnostizieren und haben oft schlechte Prognosen. Eine Forschergruppe unter der Leitung der Goethe-Universität will nun die Entstehung »Reifer T-Zell-Lymphome« besser verstehen und damit die Heilungschancen erhöhen. Die kürzlich von der Deutschen Forschungsgemeinschaft (DFG) bewilligte Forschergruppe wird in den kommenden drei Jahren mit zwei Millionen Euro gefördert.
Die Transkription ist ein entscheidender Schritt in der Transition der genetischen Information, welche durch die DNA codiert und im Genom hinterlegt ist, zu dreidimensionalen Funktionseinheiten in der Zelle, den Proteinen. Während der Transkription wird die Information von der Ebene der DNA in RNA umgewandelt, welche in der Zelle zusätzlich zu dessen Rolle als Informationsmediator in Form der mRNA eine Vielzahl von Funktionen ausübt. Die Transkription benötigt in Hinblick auf ihre essentielle Rolle in der Errichtung des Proteoms und der notwendigen Adaption von Genexpressionsprogrammen an externe zelluläre Stimuli, den Zellzyklus etc. eine präzise und gleichzeitig flexible Regulation. Besonders für die Transkription von mRNA dient die eukaryotische RNA-Polymerase II (RNAP II) in diesem Prozess als eine zentrale Einheit, die einer Vielzahl regulativer Mechanismen wie post-translationaler Modifikationen und der Assemblierung dynamischer Proteinkomplexe unterliegt. Während Komponenten dieser Regulation wie die Zusammensetzung und Dynamik des Prä-Initiationskomplex bereits seit Jahrzehnten beschrieben sind, ist eine besondere Form der RNAP II-abhängigen Regulation erst in den letzten Jahren Gegenstand genauerer Untersuchungen geworden. So erfährt die RNAP II bei einer Vielzahl von Genen unmittelbar nach der Initiation einen Arrest, der das Enzym nicht weiter über die DNA prozessieren lässt und somit die produktive Elongation des Gens blockiert. Die Aufhebung dieser Blockade wird durch den positiven Transkriptions-elongationsfaktor b (P-TEFb) dominiert, der durch distinkte post-translationale Modifikationen der C-terminalen Domäne der RNAP II und assoziierter Faktoren die produktive Elongation ermöglicht. P-TEFb selbst unterliegt dabei einer strengen Regulation durch eine inaktivierende Assoziation mit Speicherkomplexen. P-TEFb wurde abseits dieser Komplexe in einer Vielzahl von Elongations-assoziierten Proteinkomplexen identifiziert, der Mechanismus der Transition aus dem inaktiven Speicherkomplex zur aktiven Form an der RNAP II war jedoch unbekannt.
Ein zentrales Element aller aktiven Komplexe ist die Anwesenheit von Proteinen der AF4/FMR2-Familie, darunter das AF4 Protein. Bemerkenswerterweise war die genaue Rolle dieses Proteins in den Komplexen bisher unbekannt oder wurde lediglich auf die strukturelle Integrität der Komplexe beschränkt. AF4 und speziell dessen N-Terminus ist über diese Rolle hinaus als Bestandteil des Fusionsproteins AF4-MLL eng mit der onkogenen Zelltransformation im Falle einer durch die t(4;11)(q21;q23) chromosomalen Translokation bedingter, akuter lymphoblastischer Leukämie assoziiert.
In dieser Arbeit konnte gezeigt werden, dass das AF4 Protein und im Speziellen sein N-Terminus in der Lage ist, die zelluläre Transkription durch die Aktivierung und Rekrutierung von P-TEFb zu aktivieren. In Anwesenheit von AF4 wird die Kinase-Untereinheit CDK9 des P-TEFb post-translational an Lysinresten modifiziert und damit aktiviert sowie die C-terminale Domäne der RNAP II im Kontext stärker phosphoryliert. Gleichzeitig wurde das P-TEFb inaktivierende Protein HEXIM1 stärker exprimiert. AF4 und AF4-MLL waren weiterhin in der Lage ein Elongations-kontrolliertes Reportergen zu aktivieren. Gleichzeitig führte die Überexpression des AF4 zu einer Erhöhung der zellulären RNA Menge. Zur genaueren Untersuchung der AF4-abhängigen Mechanismen wurden zwei Zelllinien erstellt, die zum Einen eine induzierbare und reproduzierbare Überexpression und Reinigung des AF4 erlaubten (TCZP-AF4ST) und zum Anderen durch lentiviralen knock-down eine an AF4-Mangelsituation nachstellten (AF4kd V100). Es konnte so gezeigt werden, dass AF4 über P-TEFb hinaus eine regulative Funktion gegenüber Transkription-assoziierten Faktoren wie CDK7, MENIN und NF?B besitzt und dass diese Faktoren vorrangig, analog zu P-TEFb, mit dem N-Terminus des AF4 interagieren. Die Überexpression von AF4 führte über die Bindung an die 7SK snRNA und deren Degradation zur Rekrutierung des P-TEFb aus den Speicherkomplexen in distinkte AF4-assoziierte Komplexe und zu einer Umverteilung des Faktors auf distinkte Loci im Zellkern, wobei der AF4 N-Terminus für sich alleine jedoch nicht in der Lage war, diese Funktion auszuüben. Im Falle eines Mangels an AF4 kam es zur Wachstumsretardierung der Zellen sowie zu einem völligen Aktivitätsverlust in Reportergenversuchen.
Die Tatsache, dass AF4 ein zentrales Element in der Elongationskontrolle darstellt führte zu der weitergehenden Vermutung, dass virale immediate early (IE) Proteine zur Kontrolle viraler Genexpression auf der Ebene der Elongation ebenfalls auf dieses Wirtsprotein zugreifen können. Es konnte vor diesem Hintergrund gezeigt werden, dass AF4 tatsächlich mit den IE-Proteinen IE1 (HCMV) und Zta (EBV) aus der Familie der Herpesviren interagiert und durch die Stabilisierung des AF4 Proteins eine kooperative, transaktivierende Funktion auf ein ALOX5 Reportergen ausgeübt wurde. Es wurde gezeigt, dass die viralen IE-Proteine dabei Komponenten der AF4 Komplexe sind und in der Zelle zur epigenetischen Regulation des ALOX5 Gens führen. Weiterhin konnte in diesen Experimenten dargestellt werden, dass AF4 über seine Rolle in der Elongationskontrolle hinaus auch distinkte Effekte in der Aktivierung von Promotoren und damit in der Initiation der Transkription zeigt. Damit konnte in dieser Arbeit zum ersten Mal die essentielle Rolle des AF4 Proteins in der Elongationskontrolle und der Initiation der Transkription als auch in der Infektion durch Herpesviren gezeigt werden.
Purpose: Aberrant PI3K/AKT/mTOR signaling has been linked to oncogenesis and therapy resistance in various malignancies including leukemias. In Philadelphia chromosome (Ph) positive leukemias, activation of PI3K by dysregulated BCR-ABL tyrosine kinase (TK) contributes to the pathogenesis and development of resistance to ABL-TK inhibitors (TKI). The PI3K pathway thus is an attractive therapeutic target in BCR-ABL positive leukemias, but its role in BCR-ABL negative ALL is conjectural. Moreover, the functional contribution of individual components of the PI3K pathway in ALL has not been established.
Experimental design: We compared the activity of the ATP-competitive pan-PI3K inhibitor NVP-BKM120, the allosteric mTORC1 inhibitor RAD001, the ATP-competitive dual PI3K/mTORC1/C2 inhibitors NVP-BEZ235 and NVP-BGT226 and the combined mTORC1 and mTORC2 inhibitors Torin 1, PP242 and KU-0063794 using long-term cultures of ALL cells (ALL-LTC) from patients with B-precursor ALL that expressed the BCR-ABL or TEL-ABL oncoproteins or were BCR-ABL negative.
Results: Dual PI3K/mTOR inhibitors profoundly inhibited growth and survival of ALL cells irrespective of their genetic subtype and their responsiveness to ABL-TKI. Combined suppression of PI3K, mTORC1 and mTORC2 displayed greater antileukemic activity than selective inhibitors of PI3K, mTORC1 or mTORC1 and mTORC2.
Conclusions: Inhibition of the PI3K/mTOR pathway is a promising therapeutic approach in patients with ALL. Greater antileukemic activity of dual PI3K/mTORC1/C2 inhibitors appears to be due to the redundant function of PI3K and mTOR. Clinical trials examining dual PI3K/mTORC1/C2 inhibitors in patients with B-precursor ALL are warranted, and should not be restricted to particular genetic subtypes.
Despite advances in allogeneic stem cell transplantation, BCR-ABL-positive acute lymphoblastic leukaemia (ALL) remains a high-risk disease, necessitating the development of novel treatment strategies. As the known oncomir, miR-17~92, is regulated by BCR-ABL fusion in chronic myeloid leukaemia, we investigated its role in BCR-ABL translocated ALL. miR-17~92-encoded miRNAs were significantly less abundant in BCR-ABL-positive as compared to -negative ALL-cells and overexpression of miR-17~19b triggered apoptosis in a BCR-ABL-dependent manner. Stable isotope labelling of amino acids in culture (SILAC) followed by liquid chromatography and mass spectroscopy (LC-MS) identified several apoptosis-related proteins including Bcl2 as potential targets of miR-17~19b. We validated Bcl2 as a direct target of this miRNA cluster in mice and humans, and, similar to miR-17~19b overexpression, Bcl2-specific RNAi strongly induced apoptosis in BCR-ABL-positive cells. Furthermore, BCR-ABL-positive human ALL cell lines were more sensitive to pharmacological BCL2 inhibition than negative ones. Finally, in a xenograft model using patient-derived leukaemic blasts, real-time, in vivo imaging confirmed pharmacological inhibition of BCL2 as a new therapeutic strategy in BCR-ABL-positive ALL. These data demonstrate the role of miR-17~92 in regulation of apoptosis, and identify BCL2 as a therapeutic target of particular relevance in BCR-ABL-positive ALL.
Background: MicroRNAs circulating in the blood, stabilized by complexation with proteins and/or additionally by encapsulation in lipid vesicles, are currently being evaluated as biomarkers. The consequences of their differential association with lipids/vesicles for their stability and use as biomarkers are largely unexplored and are subject of the present study.
Methods: The levels of a set of selected microRNAs were determined by quantitative reverse-transcription PCR after extraction from sera or vesicle- and non-vesicle fractions prepared from sera. The stability of these microRNAs after incubation with RNase A or RNase inhibitor, an inhibitor of RNase A family enzymes was studied.
Results: The levels of microRNA-1 and microRNA-122, but not those of microRNA-16, microRNA-21 and microRNA-142-3p, declined significantly during a 5-h incubation of the sera. RNase inhibitor prevented the loss of microRNAs in serum as well as the degradation of microRNA-122, a microRNA not expressed in blood cells, in whole blood. Stabilization of microRNA-122 was also achieved by hemolysis. Prolonged incubation of the sera led to enrichment of vesicle-associated relative to non-vesicle-associated microRNAs. Vesicle-associated microRNAs were more resistant to RNase A treatment than the respective microRNAs not associated with vesicles.
Conclusions: Serum microRNAs showed differential stability upon prolonged incubation. RNase inhibitor might be useful to robustly preserve the pattern of cell-free circulating microRNAs. In the case of microRNAs not expressed in blood cells this can also be achieved by hemolysis. Vesicle-associated microRNAs appeared to be more stable than those not associated with vesicles, which might be useful to disclose additional biomarker properties of miRNAs.
Introduction: Acute kidney injury (AKI) can evolve quickly and clinical measures of function often fail to detect AKI at a time when interventions are likely to provide benefit. Identifying early markers of kidney damage has been difficult due to the complex nature of human AKI, in which multiple etiologies exist. The objective of this study was to identify and validate novel biomarkers of AKI.
Methods: We performed two multicenter observational studies in critically ill patients at risk for AKI - discovery and validation. The top two markers from discovery were validated in a second study (Sapphire) and compared to a number of previously described biomarkers. In the discovery phase, we enrolled 522 adults in three distinct cohorts including patients with sepsis, shock, major surgery, and trauma and examined over 300 markers. In the Sapphire validation study, we enrolled 744 adult subjects with critical illness and without evidence of AKI at enrollment; the final analysis cohort was a heterogeneous sample of 728 critically ill patients. The primary endpoint was moderate to severe AKI (KDIGO stage 2 to 3) within 12 hours of sample collection.
Results: Moderate to severe AKI occurred in 14% of Sapphire subjects. The two top biomarkers from discovery were validated. Urine insulin-like growth factor-binding protein 7 (IGFBP7) and tissue inhibitor of metalloproteinases-2 (TIMP-2), both inducers of G1 cell cycle arrest, a key mechanism implicated in AKI, together demonstrated an AUC of 0.80 (0.76 and 0.79 alone). Urine [TIMP-2].[IGFBP7] was significantly superior to all previously described markers of AKI (P <0.002), none of which achieved an AUC >0.72. Furthermore, [TIMP-2].[IGFBP7] significantly improved risk stratification when added to a nine-variable clinical model when analyzed using Cox proportional hazards model, generalized estimating equation, integrated discrimination improvement or net reclassification improvement. Finally, in sensitivity analyses [TIMP-2].[IGFBP7] remained significant and superior to all other markers regardless of changes in reference creatinine method.
Conclusions: Two novel markers for AKI have been identified and validated in independent multicenter cohorts. Both markers are superior to existing markers, provide additional information over clinical variables and add mechanistic insight into AKI. Trial registration: ClinicalTrials.gov number NCT01209169.
The live attenuated yellow fever (YF) vaccine has an excellent record of efficacy and one dose provides long-lasting immunity, which in many cases may last a lifetime. Vaccination stimulates strong innate and adaptive immune responses, and neutralizing antibodies are considered to be the major effectors that correlate with protection from disease. Similar to other flaviviruses, such antibodies are primarily induced by the viral envelope protein E, which consists of three distinct domains (DI, II, and III) and is presented at the surface of mature flavivirions in an icosahedral arrangement. In general, the dominance and individual variation of antibodies to different domains of viral surface proteins and their impact on neutralizing activity are aspects of humoral immunity that are not well understood. To gain insight into these phenomena, we established a platform of immunoassays using recombinant proteins and protein domains that allowed us to dissect and quantify fine specificities of the polyclonal antibody response after YF vaccination in a panel of 51 vaccinees as well as determine their contribution to virus neutralization by serum depletion analyses. Our data revealed a high degree of individual variation in antibody specificities present in post-vaccination sera and differences in the contribution of different antibody subsets to virus neutralization. Irrespective of individual variation, a substantial proportion of neutralizing activity appeared to be due to antibodies directed to complex quaternary epitopes displayed on the virion surface only but not on monomeric E. On the other hand, DIII-specific antibodies (presumed to have the highest neutralizing activity) as well as broadly flavivirus cross-reactive antibodies were absent or present at very low titers. These data provide new information on the fine specificity as well as variability of antibody responses after YF vaccination that are consistent with a strong influence of individual-specific factors on immunodominance in humoral immune responses.
Author Summary: The live-attenuated yellow fever vaccine has been administered to more than 600 million people worldwide and is considered to be one of the most successful viral vaccines ever produced. Following injection, the apathogenic vaccine virus replicates in the vaccinee and induces antibodies that mediate virus neutralization and subsequent protection from disease. In principle, many different antibodies are induced by viral antigens, but it is becoming increasingly clear that only a subset of them is capable of inactivating the virus, and some antibody populations appear to dominate the immune response. However, to date there has been very little information on individual-specific variations of immunodominance and how such variations can affect the functionality of antibody responses. In our study, we addressed these issues and analyzed the fine specificities of antibodies induced by YF vaccination as well as the contribution of different antibody subsets to virus neutralization in 51 vaccinees. We demonstrate an extensive degree of individual variation with respect to immunodominance of antibody populations and their contribution to virus neutralization. Such variations can have an impact on vaccine-mediated protection, and thus insight into this phenomenon can provide leads for novel strategies in modern vaccine design.
Introduction: We aimed at dissociating the neural correlates of memory disorders in Alzheimer’s disease (AD) and frontotemporal lobar degeneration (FTLD).
Methods: We included patients with AD (n = 19, 11 female, mean age 61 years) and FTLD (n = 11, 5 female, mean age 61 years) in early stages of their diseases. Memory performance was assessed by means of verbal and visual memory subtests from the Wechsler Memory Scale (WMS-R), including forgetting rates. Brain glucose utilization was measured by [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) and brain atrophy by voxel-based morphometry (VBM) of T1-weighted magnetic resonance imaging (MRI) scans. Using a whole brain approach, correlations between test performance and imaging data were computed separately in each dementia group, including a group of control subjects (n = 13, 6 female, mean age 54 years) in both analyses. The three groups did not differ with respect to education and gender.
Results: Patients in both dementia groups generally performed worse than controls, but AD and FTLD patients did not differ from each other in any of the test parameters. However, memory performance was associated with different brain regions in the patient groups, with respect to both hypometabolism and atrophy: Whereas in AD patients test performance was mainly correlated with changes in the parieto-mesial cortex, performance in FTLD patients was correlated with changes in frontal cortical as well as subcortical regions. There were practically no overlapping regions associated with memory disorders in AD and FTLD as revealed by a conjunction analysis.
Conclusion: Memory test performance may not distinguish between both dementia syndromes. In clinical practice, this may lead to misdiagnosis of FTLD patients with poor memory performance. Nevertheless, memory problems are associated with almost completely different neural correlates in both dementia syndromes. Obviously, memory functions are carried out by distributed networks which break down in brain degeneration.
In der vorliegenden Arbeit wird untersucht, wie das Gehirn Bewusstsein erzeugt. Diese Frage wird als eines der größten Rätsel der heutigen Wissenschaft angesehen: Wie kann es sein, dass aus der Aktivität der Nervenzellen unsere subjektive Welt entsteht? Es ist offensichtlich nicht einfach, diese Frage wissenschaftlich zu untersuchen. Eine der vorgeschlagenen Strategien für die Untersuchung von Bewusstsein behauptet, dass man zunächst die neuronalen Korrelate des Bewusstseins finden sollte (Koch, 2004). Einer Definition zufolge sind die neuronalen Korrelate des Bewusstseins die kleinste Menge neuronaler Prozesse, die hinreichend für eine bestimmte bewusste Erfahrung sind (zum Beispiel für die bewusste Erfahrung des Blaubeergeschmacks). Manche behaupteten, die Entdeckung der neuronalen Korrelate des Bewusstseins würde es erlauben, dem Rätsel des Bewusstseins näher zu kommen (Crick & Koch, 1990). Nur wie soll man die neuronalen Korrelate des Bewusstseins finden? Eine relativ einfache Strategie dafür wurde schon vor mehr als 20 Jahren beschrieben. Es sollten einfach experimentelle Bedingungen erschaffen werden, in welchen ein Reiz manchmal bewusst wahrgenommen wird und manchmal nicht (Baars, 1989). Solche Analysen, die Bedingungen mit und ohne bewusste Wahrnehmung vergleichen, werden als „Kontrastierungsanalyse“ bezeichnet (da zwei Bedingungen miteinander kontrastiert werden). Es existieren viele verschiedene experimentelle Paradigmen, bei welchen man den Reiz unter denselben Bedingungen präsentieren kann, so dass er bei manchen Versuchsdurchgängen bewusst wahrgenommen wird, bei anderen nicht (Kim & Blake, 2005). Mit solchen experimentellen Paradigmen kann man angeblich die neuronalen Korrelate des Bewusstseins finden, wenn man a) bei jedem Durchgang die Versuchsperson fragt, ob oder was die Versuchsperson bei dem Durchgang wahrgenommen hat und b) gleichzeitig die neuronalen Prozesse misst (zum Beispiel mit EEG, MEG oder fMRT). Anschließend kann man die erhobenen neuronalen Daten unter den Bedingungen mit und ohne bewusste Wahrnehmung vergleichen.
Mittlerweile gibt es viele Studien, in denen solche experimentelle Paradigmen – und damit die Kontrastierungsanalyse – angewendet wurden. Insofern könnte man glauben, die neuronalen Korrelate des Bewusstseins seien schon gefunden worden. Allerdings ist dies nicht der Fall. Es existiert in der Literatur weiterhin Uneinigkeit darüber, ob die Korrelate des Bewusstseins früh oder spät in der Zeit liegen, und ob die Korrelate in sensorischen Arealen oder eher im hierarchisch höheren fronto-parietalen Kortex zu finden sind.
Nach unserer Meinung sind die experimentellen Paradigmen, die üblicherweise zum Auffinden der neuronalen Korrelate des Bewusstseins verwendet werden, nicht spezifisch genug, um diese eindeutig zu lokalisieren. Eher glauben wir, dass die klassische Kontrastierungsanalyse auch andere Prozesse als Ergebnisse hervorbringt und uns deshalb prinzipiell nicht zu den neuronalen Korrelaten des Bewusstseins führen kann.
Im Kapitel 2 wird erklärt, wieso die typischen experimentellen Paradigmen nicht die neuronalen Korrelate des Bewusstseins ausfindig machen können. Wir behaupten, dass der Vergleich neuronaler Daten aus experimentellen Bedingungen mit und ohne bewusste Wahrnehmung auch die neuronalen Prozesse widerspiegeln könnte, die bewussten Wahrnehmungen entweder vorausgehen oder folgen. Es ist beispielsweise bekannt, dass neuronale Prozesse vor Auftreten des Reizes darüber bestimmen können, ob der Reiz bewusst wahrgenommen wird oder nicht (Busch, Dubois, & VanRullen, 2009; Mathewson, Gratton, Fabiani, Beck, & Ro, 2009). Wenn man experimentelle Bedingungen mit und ohne bewusster Wahrnehmung miteinander vergleicht, werden auch solche Prozesse als Ergebnis auftauchen, obwohl diese zeitlich klar vor dem Reiz stattfinden und deshalb keine neuronalen Korrelate des Bewusstseins sein können. Es ist natürlich einfach zu entscheiden, dass diese Prozesse, die schon vor dem Reiz stattfinden, der bewussten Wahrnehmung vorausgehen müssen, aber es ist unmöglich zu sagen, ob ein neuronaler Prozess 100 oder 200 Millisekunden nach der Präsentation des Reizes immer noch ein Vorläuferprozess ist schon ein neuronales Korrelat des Bewusstseins darstellt. Deshalb ist die typische Kontrastierungsanalyse nicht spezifisch genug und wir wissen nicht, ob neuronale Prozesse, die durch die Kontrastierungsanalyse aufgedeckt werden, direkt die neuronalen Korrelate des Bewusstseins oder eher Prozesse vor der bewussten Wahrnehmung widerspiegeln.
Nicht nur die Vorläuferprozesse der bewussten Warnehmung stellen ein Problem dar. Auch Konsequenzen der bewussten Verarbeitung werden durch die Kontrastierungsanalyse gefunden. Beispielsweise wurden im medialen Temporallappen Neurone gefunden, die nur dann feuern, wenn ein Patient eine Person auf einem Bild bewusst erkennt, aber nicht feuern, wenn der Patient die Person auf dem Bild nicht bewusst wahrnimmt (Quiroga, Mukamel, Isham, Malach, & Fried, 2008). So könnte man vorerst meinen, dass das Feuern dieser Neurone das neuronale Korrelat des Bewusstseins sein könnte. Nach einer Läsion, sprich neuronalen Schädigung des medialen Temporallappens kann man die Welt jedoch weiterhin bewusst wahrnehmen (man hat jedoch Probleme mit dem Gedächtnis und Wiedererkennen). Insofern kann das Feuern dieser Neurone nicht das neuronale Korrelat des Bewusstseins sein und ist eher ein Beispiel für die Konsequenz der bewussten Verarbeitung. Wir behaupten, dass es noch viele andere solcher Vorläuferprozesse und Konsequenzen gibt, die notwendigerweise als Ergebnis bei der Kontrastierungsanalyse auftauchen, und also ist die typische Kontrastierungsanalyse extrem unspezifisch bezüglich der neuronalen Korrelate des Bewusstseins. In anderen Worten: Die typische Kontrastierungsanalyse, bei welcher man experimentelle Bedingungen mit und ohne bewusste Wahrnehmung miteinander vergleicht, wird uns nicht helfen die neuronalen Korrelate des Bewusstseins zu finden.
Wir glauben, dass neue experimentelle Paradigmen entwickelt werden sollten, um die neuronalen Korrelate des Bewusstseins ausfindig zu machen. Wahrscheinlich gibt es kein einfaches Experiment, mit dem man die Vorläuferprozesse und Konsequenzen vollständig vermeiden kann, um damit direkt die neuronalen Korrelate des Bewusstseins zu bestimmen. Eher braucht man viele verschiedene Experimente, die Schritt für Schritt unser Wissen über die neuronalen Korrelate des Bewusstseins erweitern.
In der vorliegenden Arbeit (in Kapiteln 3, 4 und 5) wird ein neues experimentelles Paradigma angewandt. Dieses Paradigma wird nicht alle oben erwähnten Probleme lösen, wird aber hoffentlich erlauben, einige Vorläuferprozesse der bewussten Wahrnehmung von den neuronalen Korrelaten des Bewusstseins auseinanderzuhalten. Der Vorteil unseres experimentellen Paradigmas besteht darin, dass die bewusste Wahrnehmung durch zwei verschiedene Vorläuferprozesse beeinflusst wird. Die Versuchspersonen müssen auf schnell präsentierten und mittels Rauschens undeutlich gemachten Bildern eine Person detektieren. Die experimentellen Bedingungen sind derart gestaltet, dass die Versuchspersonen nicht bei jedem Durchgang die Person auf dem Bild wahrnehmen können. Damit können wir den Wahrnehmungsprozess manipulieren. Bei einer Manipulation variieren wir den Anteil des Rauschens auf dem Bild und damit die sensorische Evidenz. Je weniger Rauschen, desto besser können die Versuchspersonen die Bilder wahrnehmen und desto öfter sehen sie auch bewusst die Person auf dem Bild. Bei der anderen experimentellen Manipulation der Wahrnehmung werden einige Bilder den Versuchspersonen vorher klar und ohne Rauschen gezeigt. Damit erschafft man Wissen über bestimmte Bilder, die später mit Rauschen präsentiert werden. Man kann zeigen, dass solch bestehendes Wissen tatsächlich die Wahrnehmung beeinflusst. Wenn die Versuchspersonen bestehendes Wissen über ein Bild haben, ist es wahrscheinlicher, dass sie die Person auf dem Bild bewusst wahrnehmen. Damit haben wir zwei verschiedene Vorläuferprozesse – sensorische Evidenz und bestehendes Wissen, die beide die bewusste Wahrnehmung beeinflussen. Beide Vorläuferprozesse erhöhen den Anteil der Durchgänge, in welchen die Versuchspersonen die Person auf dem Bild bewusst wahrnehmen.
Mit diesem experimentellen Paradigma möchten wir einige Aussagen über die neuronalen Korrelate des Bewusstseins testen. Wenn über einen neuronalen Prozess behauptet wird, dass er einem neuronalen Korrelat des Bewusstseins entspricht, müsste dieser Prozess von den beiden manipulierten Vorläuferprozessen in ähnlicher Weise beeinflusst werden, da bewusste Wahrnehmung durch beide manipulierten Vorläuferprozessen in ähnlicher Weise erleichtert wird. Wenn aber der Prozess, über den behauptet wird, er sei ein neuronales Korrelat des Bewusstseins, nicht durch beide Manipulationen geändert wird, kann dieser Prozess kein neuronales Korrelat des Bewusstseins sein, da er nicht beeinflusst wird, obwohl die bewusste Wahrnehmung geändert wurde.
Mit diesem experimentellen Paradigma und dieser Logik haben wir zwei unterschiedliche neuronale Prozesse getestet, von denen behauptet wird, dass sie den neuronalen Korrelaten des Bewusstseins entsprechen könnten. In Kapitel 3 wurde untersucht, ob lokale kategorienspezifische Gammabandaktivität die neuronalen Korrelate des Bewusstseins reflektieren könnte. In Kapitel 4 wurde mit diesem experimentellen Paradigma untersucht, ob die neuronale Synchronisierung dem neuronalen Korrelat des Bewusstseins entsprechen könnte.
Unsere Arbeit im Kapitel 3 baut auf der von Fisch und Kollegen (2009) auf. Fisch und Kollegen (2009) zogen aus ihrer experimentellen Arbeit den Schluss, dass lokale kategorienspezifische Gammabandaktivität die neuronalen Korrelate des Bewusstseins reflektieren könnte. Sie hatten Elektroden auf dem visuellen Kortex von Epilepsiepatienten implantiert und von diesen Elektroden die Gammabandaktivität abgeleitet. Im ersten Schritt suchten sie nach Elektroden, die kategorienspezifische Antworten zeigen. Bei den kategorienspezifischen Elektroden ist die Gammabandaktivität abhängig vom präsentierten Stimulusmaterial. Zum Beispiel kann man bei einer Elektrode auf dem Fusiform Face Area starke Gammabandaktivität nur dann messen, wenn ein Gesicht auf dem Bild zu sehen ist. Die Autoren benutzten solche kategorienspezifischen Elektroden, um nach den neuronalen Korrelaten des Bewusstseins zu suchen. Sie zeigten den Patienten Bilder von Gesichtern, Häusern und Objekten, die direkt nach der kurzen Präsentation maskiert wurden, so dass die Patienten nur bei manchen Durchgängen erkannten, was auf dem Bild war, bei anderen Durchgängen nicht. Dies entspricht der typischen Kontrastierungsanalyse. Die Ergebnisse haben klar gezeigt, dass bei diesen kategorienspezifischen Elektroden die Gammabandaktivität erhöht wurde, als die Patienten bewusst wahrnahmen, was auf dem Bild zu sehen war. Aus diesen Ergebnissen zogen die Autoren den Schluss, dass lokale kategorienspezifische Gammabandaktivität dem neuronalen Korrelat des Bewusstseins entspricht. Diese Aussage wollten wir mit unserem experimentellen Paradigma testen.
Um diese Behauptung zu untersuchen, erhoben wir sehr ähnliche Daten wie Fisch et al. (2009) und analysierten die Daten auf ähnliche Weise. Unsere experimentelle Frage war, ob die lokale kategorienspezifische Gammabandaktivität durch unsere beiden Manipulationen – sensorische Evidenz und bestehendes Wissen – in ähnlicher Weise erhöht wird. Dies sollte der Fall sein, wenn die lokale kategorienspezifische Gammabandaktivität dem neuronalen Korrelat des Bewusstseins entspricht, da sensorische Evidenz und bestehendes Wissen beide den Anteil der Durchgänge, in welchen die Versuchsperson die Person auf dem Bild bewusst wahrnimmt, erhöhen. Dieses Ergebnis wurde nicht gefunden. Stattdessen fanden wir, dass die lokale kategorien-spezifische Gammabandaktivität nur durch sensorische Evidenz erhöht wurde, bestehendes Wissen aber keinen Effekt auf diese Aktivierung hatte. Da bestehendes Wissen auch den Anteil der Durchgänge mit bewusster Wahrnehmung erhöht, die kategorienspezifische Gammabandaktivität aber nicht durch bestehendes Wissen erhöht wurde, kann man schlussfolgern, dass die kategorienspezifische Gammabandaktivität nicht die neuronalen Korrelate des Bewusstseins reflektieren kann.
Als nächstes (Kapitel 4) haben wir die Hypothese getestet, dass Synchronizität dem neuronalen Korrelat des Bewusstseins entspricht. Um diese Idee zu testen, maßen wir mittels Magnetoenzephalographie die magnetischen Felder des Gehirns, schätzten aus diesen Daten mittels Beamforming die neuronalen Aktivitätsquellen und quantifizierten die Synchronizität zwischen diesen Quellen. Wenn die interareale Synchronizität dem neuronalen Korrelat des Bewusstseins entspräche, sollte die Synchronizität für Bedingungen mit mehr sensorischer Evidenz und mit bestehendem Wissen erhöht sein. Dies wurde nicht beobachtet. Wir fanden, dass Synchronizität (gemittelt über die Quellen) nur bei den Bildern erhöht war, für die bestehendes Wissen vorlag. Ein ähnlicher Effekt für sensorische Evidenz wurde nicht gefunden. Insofern können wir sagen, dass unsere Befunde dagegen sprechen, dass neuronale Synchronizität den Mechanismus für Bewusstsein darstellt. Allerdings können wir das in diesem Fall auch nicht völlig ausschließen, denn Synchronizität könnte die Informationsverarbeitung auf einem kleineren Maßstab koordinieren als wir es mit dem MEG messen können (Singer, in press).
Im Kapitel 5 untersuchten wir, wie schnell bestehendes Wissen bewusste Verarbeitung beeinflussen kann. Um dies herauszufinden machten wir uns die intraindividuellen Unterschiede der perzeptuellen Leistung zu Nutze. Wir fanden, dass bestehendes Wissen bewusste Verarbeitung schon innerhalb der ersten 100 Millisekunden nach der Präsentation des Reizes beeinflusst. Wir beobachteten auch, dass ein größerer perzeptueller Effekt des bestehenden Wissens in geringerer neuronaler Aktivität in Durchgängen mit bestehendem Wissen hervorruft. Diese Ergebnisse sind im Einklang mit Theorien, die besagen, dass unsere Wahrnehmung bestehendes Wissen nutzt, um vorherzusagen, wie die visuelle Welt sich ändert und um die neuronalen Antworten zu verringern (Friston, 2010).
In der vorliegenden Arbeit wurde diskutiert, warum die typische Kontrastierungsanalyse uns nicht zu den neuronalen Korrelaten des Bewusstseins führen kann. Wir schlugen vor, dass neue experimentelle Paradigmen nötig sind, um näher an die neuronalen Korrelate des Bewusstseins heranzukommen. Es wurde ein neues Paradigma benutzt, um zwischen Vorläuferprozessen und neuronalen Korrelate des Bewusstseins zu unterscheiden. Mit diesem Paradigma wurden zwei sehr unterschiedliche Hypothesen getestet und gefunden, dass die kategorienspezifische Gammabandaktivität nicht die neuronalen Korrelate des Bewusstseins widerspiegeln kann. Wir hoffen, dass unsere Experimente eine Entwicklung von vielen weiteren und besseren experimentellen Paradigmen stimuliert, die zwischen den Vorläuferprozessen, den Konsequenzen und den eigentlichen Korrelaten des Bewusstseins unterscheiden können. Wenn man über die Kontrastierungsanalyse hinausgeht, kann man die gegenwärtigen Theorien des Bewusstseins testen und damit Schritt für Schritt näher an die neuronalen Grundlagen des Bewusstseins kommen.
Objective. To test the influence of personalized ultrasound (PersUS) on patient management in critical care. Design of the Study. Prospective, observational, and critical care setting. Four substudies compared PersUS and mobile ultrasound, work distribution, and diagnostic and procedural quality. Patients and Interventions. 640 patient ultrasound exams including 548 focused diagnostic exams and 92 interventional procedures. Main Outcome Measures. Number of studies, physician’s judgement of feasibility, time of usage per patient, and referrals to echo lab. Results. Randomized availability of PersUS increased its application in ICU work shifts more than twofold from 33 to 68 exams mainly for detection and therapy of effusions. Diagnostic and procedural quality was rated as excellent/very good in PersUS-guided puncture in 95% of cases. Integrating PersUS within an initial physical examination of 48 randomized cases in an emergency department, PersUS extended the examination time by 100 seconds. Interestingly, PersUS integration into 53 randomized regular ward rounds of 1007 patients significantly reduced average contact time per patient by 103 seconds from 8.9 to 7.2 minutes. Moreover, it lowered the patient referral rate to an echo lab from 20% to 2% within the study population. Conclusions. We propose the development of novel ultrasound-based clinical pathways by integration of PersUS.
For the pathologist, the diagnosis of drug induced liver injury (DILI) is challenging, because histopathological features mimic all primary hepatic and biliary diseases, lacking changes that are specific for DILI. Therefore, in any patient of suspected DILI who underwent liver biopsy, the pathologist will assure the clinician that the observed hepatic changes are compatible with DILI, but this information is less helpful due to lack of specificity. Rather, the pathologist should assess liver biopsies blindly, without knowledge of prior treatment by drugs. This will result in a detailed description of the histological findings, associated with suggestions for potential causes of these hepatic changes. Then, it is up to the physician to reassess carefully the differential diagnoses, if not done before. At present, liver histology is of little impact establishing the diagnosis of DILI with the required degree of certainty, and this shortcoming also applies to herb induced liver injury (HILI). To reach at the correct diagnoses of DILI and HILI, clinical and structured causality assessments are therefore better approaches than liver histology results obtained through liver biopsy, an invasive procedure with a low complication rate.