610 Medizin und Gesundheit
Refine
Year of publication
- 2013 (350) (remove)
Document Type
- Article (265)
- Doctoral Thesis (34)
- Conference Proceeding (14)
- Part of Periodical (14)
- Contribution to a Periodical (12)
- Book (3)
- Review (3)
- Part of a Book (2)
- Periodical (2)
- Preprint (1)
Is part of the Bibliography
- no (350)
Keywords
- Video (19)
- Capsule endoscopy (12)
- Small bowel (10)
- Endoscopy (7)
- Balloon enteroscopy (6)
- Enteroscopy (6)
- Endoscopic retrograde cholangiopancreatography (4)
- Apoptosis (3)
- IAP proteins (3)
- Smac (3)
Institute
- Medizin (276)
- Präsidium (25)
- Pharmazie (13)
- Biowissenschaften (12)
- Georg-Speyer-Haus (11)
- Frankfurt Institute for Advanced Studies (FIAS) (10)
- Biochemie und Chemie (9)
- Zentrum für Arzneimittelforschung, Entwicklung und Sicherheit (ZAFES) (8)
- Sportwissenschaften (5)
- Psychologie (4)
- MPI für Hirnforschung (3)
- Biochemie, Chemie und Pharmazie (2)
- Centre for Drug Research (2)
- Gesellschaftswissenschaften (2)
- Institut für Wirtschaft, Arbeit, und Kultur (IWAK) (2)
- Physik (2)
- Center for Membrane Proteomics (CMP) (1)
- Ernst Strüngmann Institut (1)
- Exzellenzcluster Die Herausbildung normativer Ordnungen (1)
- Exzellenzcluster Makromolekulare Komplexe (1)
- Geographie (1)
- Goethe-Zentrum für Wissenschaftliches Rechnen (G-CSC) (1)
- Informatik (1)
- Institut für Ökologie, Evolution und Diversität (1)
- Senckenbergische Naturforschende Gesellschaft (1)
- Universitätsbibliothek (1)
Introduction: We have recently described an increased lymphocytic infiltration rate in breast carcinoma tissue is a significant response predictor for anthracycline/taxane-based neoadjuvant chemotherapy (NACT). The aim of this study was to prospectively validate the tumor-associated lymphocyte infiltrate as predictive marker for response to anthracycline/taxane-based NACT.
Patients and Methods: The immunological infiltrate was prospectively evaluated in a total of 313 core biopsies from HER2 negative patients of the multicenter PREDICT study, a substudy of the neoadjuvant GeparQuinto study. Intratumoral lymphocytes (iTuLy), stromal lymphocytes (strLy) as well as lymphocyte-predominant breast cancer (LPBC) were evaluated by histopathological assessment. Pathological complete response (pCR) rates were analyzed and compared between the defined subgroups using the exact test of Fisher.
Results: Patients with lymphocyte-predominant breast cancer (LPBC) had a significantly increased pCR rate of 36.6%, compared to non-LPBC patients (14.3%, p<0.001). LPBC and stromal lymphocytes were significantly independent predictors for pCR in multivariate analysis (LPBC: OR 2.7, p = 0.003, strLy: OR 1.2, p = 0.01). The amount of intratumoral lymphocytes was significantly predictive for pCR in univariate (OR 1.2, p = 0.01) but not in multivariate logistic regression analysis (OR 1.2, p = 0.11).
Conclusion: Confirming previous investigations of our group, we have prospectively validated in an independent cohort that an increased immunological infiltrate in breast tumor tissue is predictive for response to anthracycline/taxane-based NACT. Patients with LPBC and increased stromal lymphocyte infiltration have significantly increased pCR rates. The lymphocytic infiltrate is a promising additional parameter for histopathological evaluation of breast cancer core biopsies.
Background: This phase I/II-trial assessed the dose-limiting toxicities (DLT) and maximum tolerated dose (MTD) of neoadjuvant radiochemotherapy (RCT) with docetaxel and oxaliplatin in patients with locally advanced adenocarcinoma of the oesophagogastric junction.
Methods: Patients received neoadjuvant radiotherapy (50.4 Gy) together with weekly docetaxel (20 mg/m2 at dose level (DL) 1 and 2, 25 mg/m2 at DL 3) and oxaliplatin (40 mg/m2 at DL 1, 50 mg/m2 at DL 2 and 3) over 5 weeks. The primary endpoint was the DLT and the MTD of the RCT regimen. Secondary endpoints included overall response rate (ORR) and progression-free survival (PFS).
Results: A total of 24 patients were included. Four patients were treated at DL 1, 13 patients at DL 2 and 7 patients at DL 3. The MTD of the RCT was considered DL 2 with docetaxel 20 mg/m2 and oxaliplatin 50 mg/m2. Objective response (CR/PR) was observed in 32% (7/22) of patients. Eighteen patients (75%) underwent surgery after RCT. The median PFS for all patients (n = 24) was 6.5 months. The median overall survival for all patients (n = 24) was 16.3 months. Patients treated at DL 2 had a median overall survival of 29.5 months.
Conclusion: Neoadjuvant RCT with docetaxel 20 mg/m2 and oxaliplatin 50 mg/m2 was effective and showed a good toxicity profile. Future studies should consider the addition of targeted therapies to current neoadjuvant therapy regimens to further improve the outcome of patients with advanced cancer of the oesophagogastric junction.
Trial Registration: NCT00374985
Background: Critical organ shortage results in the utilization of extended donor criteria (EDC) liver grafts. These marginal liver grafts are prone to increased ischemia reperfusion injury (IRI) which may contribute to deteriorated graft function and survival. Experimental data have shown that the calcineurin inhibitor tacrolimus exerts protective effects on hepatic IRI when applied intravenously or directly as a hepatic rinse. Therefore, the aim of the present study is to examine the effects of an ex vivo tacrolimus perfusion on IRI in transplantation of EDC liver grafts.
Methods/Design: The TOP-Study (tacrolimus organ perfusion) is a randomized multicenter trial comparing the ex vivo tacrolimus perfusion of marginal liver grafts with placebo. We hypothesize that a tacrolimus rinse reduces IRI, potentially improving organ survival following transplantation of EDC livers. The study includes livers with two or more EDC, according to Eurotransplant International Foundation’s definition of EDC livers. Prior to implantation, livers randomized to the treatment group are rinsed with tacrolimus at a concentration of 20 ng/ml in 1000 ml Custodiol solution and in the placebo group with Custodiol alone. The primary endpoint is the maximum serum alanine transamninase (ALT) level within the first 48 hours after surgery; however, the study design also includes a 1-year observation period following transplantation. The TOP-Study is an investigator-initiated trial sponsored by the University of Munich Hospital. Seven other German transplant centers are participating (Berlin, Frankfurt, Heidelberg, Mainz, Münster, Regensburg, Tübingen) and aim to include a total of 86 patients.
Discussion: Tacrolimus organ perfusion represents a promising strategy to reduce hepatic IRI following the transplantation of marginal liver grafts. This treatment may help to improve the function of EDC grafts and therefore safely expand the donor pool in light of critical organ shortage.
Trial register: EudraCT number: 2010-021333-31, ClinicalTrials.gov identifier: NCT01564095
Gentests an Embryonen sind in sehr begrenzten Ausnahmefällen jetzt auch in Deutschland erlaubt. In den nächsten Monaten werden an wenigen ausgewählten Kliniken Zentren zur Präimplantationsdiagnostik (PID) eingerichtet. Die Klinik für Frauenheilkunde und Geburtshilfe am Frankfurter Universitätsklinikum rechnet sich gute Chancen aus, dass ihre Bewerbung erfolgreich verläuft, so ihr Direktor Prof. Sven Becker.
This doctoral thesis is concerned with the development of a method that allows to measure in vivo and non-invasively the mid-infrared absorption spectra of human epidermis, using photoacoustic spectroscopy. The main focus is the monitoring of the glucose level in epidermal interstitial fluid and its correlation with the blood glucose level; which is the most important parameter for the diagnosis and treatment of diabetes mellitus. Most publications in this field have only reported measurements in vitro for the absorption spectra of epidermis in the mid-infrared range. Using the approach presented in this work, it was possible to record in vivo and in situ the absorption spectra of skin of volunteers; and with these spectra, the changing glucose concentration could be monitored. The novelty of the photoacoustic method introduced here is that it operates in acoustic resonance in the ultrasound range. This considerably reduces the signal noise due to the external acoustic background. Although the photoacoustic method reported in this work was used to measure glucose in human epidermis, it can also be applied to other solid samples with relevant absorption bands in the mid-infrared. Furthermore, it can be used in other spectral regions if the laser source covers relevant absorption bands of the sample.
Gegenstand dieser Arbeit ist die Untersuchung der Genexpression der axonalen wachstumsassoziierten Proteine NAP-22, GAP-43 und CAP-23 in den dopaminergen Neuronen der Substantia nigra pars compacta (SNc), einer im Mesencephalon gelegenen Zellregion, relativ zu der Genexpression eines Referenzgens. Als Versuchstiere dienten sechs Monate alte, männliche CB6F1 Wildtypmäuse sowie sechs Monate alte, männliche CAP-23 transgene (CAP-23tg) Tiere, die das wachstumsassoziierte Protein CAP-23 überexprimieren. Die dopaminergen Zellen der SNc wurden zunächst morphologisch charakterisiert und ihre Ausdehnung im Mittelhirn durch alternierende Immunfärbungen der Tyrosinhydroxylase, einem Schlüsselenzym der Dopaminsynthese, sowie Toluidinblaufärbungen ermittelt. Anschließend wurden die Neurone durch die Methode der Lasermikrodissektion (LMD) im Zellverband isoliert. Hierfür war die Optimierung der Toluidinblaufärbung erforderlich, mit dem Ziel, sowohl eine gute Färbung der Neurone als auch eine hohe RNA-Nativität zu erzielen. Die RNA wurde isoliert und nach Integritätsprüfung in cDNA umgeschrieben. Daraufhin erfolgte die Analyse der Genexpression der beschriebenen Gene durch die quantitative Echtzeit-Polymerase-Kettenreaktion (qRT-PCR). Dabei war feststellbar, dass das Transgen Cap-23 in den transgenen Tieren stärker exprimiert wird als das Endogen Nap-22. Es zeigte sich jedoch kein signifikanter Unterschied der Expression von endogenem Nap-22 und endogenem Gap-43 in den CAP-23tg Tieren im Vergleich zu der Expression in den Wildtypmäusen. Das bedeutet, dass die Überexpression von Cap-23 in den transgenen Tieren die Expression der mRNA der beiden endogenen wachstumsassoziierten Proteine NAP-22 und GAP-43 nicht beeinflusst. Auf Grundlage der in dieser Arbeit vorgelegten Ergebnisse soll in Folgeexperimenten untersucht werden, inwieweit die Überexpression von CAP-23 die Reorganisationsfähigkeit dopaminerger Neuronen der SNc nach einer Schädigung beeinflusst, wie sie zum Beispiel beim Menschen im Verlauf des Morbus Parkinson beobachtet wird.
Radiographic and safety details of vertebral body stenting : results from a multicenter chart review
(2013)
Background: Up to one third of BKP treated cases shows no appreciable height restoration due to loss of both restored height and kyphotic realignment after balloon deflation. This shortcoming has called for an improved method that maintains the height and realignment reached by the fully inflated balloon until stabilization of the vertebral body by PMMA-based cementation. Restoration of the physiological vertebral body height for pain relief and for preventing further fractures of adjacent and distant vertebral bodies must be the main aim for such a method. A new vertebral body stenting system (VBS) stabilizes the vertebral body after balloon deflation until cementation. The radiographic and safety results of the first 100 cases where VBS was applied are presented.
Methods: During the planning phase of an ongoing international multicenter RCT, radiographic, procedural and followup details were retrospectively transcribed from charts and xrays for developing and testing the case report forms. Radiographs were centrally assessed at the institution of the first/senior author.
Results: 100 patients (62 with osteoporosis) with a total of 103 fractured vertebral bodies were treated with the VBS system. 49 were females with a mean age of 73.2 years; males were 66.7 years old. The mean preoperative anterior-middle-posterior heights were 20.3-17.6-28.0 mm, respectively. The mean local kyphotic angle was 13.1°. The mean preoperative Beck Index (anterior edge height/posterior edge height) was 0.73, the mean alternative Beck Index (middle height/posterior edge height) was 0.63. The mean postoperative heights were restored to 24.5-24.6-30.4 mm, respectively. The mean local kyphotic angle was reduced to 8.9°. The mean postoperative Beck Index was 0.81, the mean alternative one was 0.82. The overall extrusion rate was 29.1%, the symptomatic one was 1%. In the osteoporosis subgroup there were 23.8% extrusions. Within the three months followup interval there were 9% of adjacent and 4% of remote new fractures, all in the osteoporotic group.
Conclusions: VBS showed its strengths especially in realignment of crush and biconcave fractures. Given that fracture mobility is present, the realignment potential is sound and increases with the severity of preoperative vertebral body deformation.
Introduction: Langerhans Cell Histiocytosis (LCH) represents a rare benign disorder, previously designated as "Histiocytosis X", "Type II Histiocytosis" or "Langerhans Cell Granulomatosis". Clinical presentation includes osteolysis, ulcerations of skin and soft tissues but also involvement of the CNS is described.Because treatment concepts are not well defined the German Cooperative Group on Radiotherapy for Benign Diseases performed a retrospective analysis.
Methods and material: Eight closely cooperating centres collected patients' data of the past 45 years. As study endpoints disease free survival, recurrent disease, death and therapy related side effects were defined.
Results: A total of 80 patients with histologically proven LCH were irradiated within the past 45 years. According to the LCH classification of Greenberger et al. 37 patients had stage Ia, 21 patients stage Ib, 13 patients stage II and 9 patients stage IIIb and the median age was 29 years. The median Follow up was 54 months (range 9-134 months). A total of 39 patients had a surgical intervention and 23 patients a chemotherapy regimen.Radiation treatment was carried out with a median total dose of 15 Gy (range 3-50.4 Gy). The median single fraction was 2 Gy (range 1.8-3 Gy).Overall, 77% patients achieved a complete remission and 12.5% achieved a partial remission. The long-term control rate reached 80%. Within an actuarial overall 5-year survival of 90% no radiogenic side and late effects ≥EORTC/RTOG II° were observed.
Conclusion: In the present study a large collective of irradiated patients was analysed. Radiotherapy (RT) is a very effective and safe treatment option and even low RT doses show sufficient local control.
Since most anticancer therapies including immunotherapy trigger programmed cell death in cancer cells, defective cell death programs can lead to treatment resistance and tumor immune escape. Therefore, evasion of programmed cell death may provide one possible explanation as to why cancer immunotherapy has so far only shown modest clinical benefits for children with cancer. A better understanding of the molecular mechanisms that regulate sensitivity and resistance to programmed cell death is expected to open new perspectives for the development of novel experimental treatment strategies to enhance the efficacy of cancer immunotherapy in the future.
Objective: The aim of the study was to analyse the psychometric properties of the EQ-5D in patients with social phobia.
Methods: We used a sample of 445 patients with social phobia with five measurement points over a 30 month period. The discriminative ability of the EQ-5D was analysed by comparing the patients' responses with the general population and between different disease severity levels. For test-retest reliability we assessed the level of agreement in patients' responses over time, when there was no change in the Liebowitz Social Anxiety Scale (LSAS). Construct validity was analysed by identifying correlations of the EQ-5D with more specific instruments. For responsiveness we compared the means of EQ VAS/EQ-5D index anchored on improved (deteriorated) health status and computed effect sizes as well as a receiver operating characteristic (ROC) curve.
Results: Compared to the general population, patients with social phobia reported more problems in the dimensions "usual activities", "pain/discomfort", and "anxiety/depression" and less problems in "mobility" and "self-care". The EQ-5D was able to distinguish between different disease severity levels. The test-retest reliability was moderate (intraclass correlation coefficient > 0.6). Correlations between the EQ-5D and other instruments were mostly small except for correlations with Beck Depression Inventory. The EQ-5D index seemed to be more responsive than the EQ VAS, but with only medium effect sizes (0.5 < effect size < 0.8) in the British EQ-5D index and only significant in patients with improved health status. The ROC analysis revealed no significant results.
Conclusions: The EQ-5D was moderately reliable and responsive in patients with improved health status. Construct validity was limited.
Trial registration: Current controlled trials ISRCTN53517394.
Targeted drugs have significantly improved the therapeutic options for advanced renal cell carcinoma (RCC). However, resistance often develops, negating the benefit of these agents. In the present study, the molecular mechanisms of acquired resistance towards the histone deacetylase (HDAC) inhibitor valproic acid (VPA) in a RCC in vivo model were investigated. NMRI:nu/nu mice were transplanted with Caki-1 RCC cells and then treated with VPA (200 mg/kg/day). Controls remained untreated. Based on tumor growth dynamics, the mice were divided into “responders” and “non-responders” to VPA. Histone H3 and H4 acetylation and expression of cell signaling and cell cycle regulating proteins in the RCC mouse tumors were evaluated by Western blotting. Tumor growth of VPA responders was significantly diminished, whereas that of VPA non-responders even exceeded control values. Cdk1, 2 and 4 proteins were strongly enhanced in the non-responders. Importantly, Akt expression and activity were massively up-regulated in the tumors of the VPA non-responders. Chronic application (12 weeks) of VPA to Caki-1 cells in vitro evoked a distinct elevation of Akt activity and cancer cells no longer responded with cell growth reduction, compared to the short 2 week treatment. We assume that chronic use of an HDAC-inhibitor is associated with (re)-activation of Akt, which may be involved in resistance development. Consequently, combined blockade of both HDAC and Akt may delay or prevent drug resistance in RCC.
Inflammation has been recognized as a common trait in the pathogenesis of multifactorial diseases including obesity, where a low-grade inflammation has been established and may be responsible for the cardiovascular risk related to the disease. Obesity has also been associated with the increased incidence and a worse outcome of rheumatoid arthritis (RA) and osteoarthritis (OA). RA is characterized by systemic inflammation, which is thought to play a key role in accelerated atherosclerosis and in the increased incidence of cardiovascular disease, an important comorbidity in patients with RA. The inflammatory process underlying the cardiovascular risk both in obesity and RA may be mediated by adipocytokines, a heterogeneous group of soluble proteins mainly secreted by the adipocytes. Many adipocytokines are mainly produced by white adipose tissue. Adipocytokines may also be involved in the pathogenesis of OA since a positive association with obesity has been found for weight-bearing and nonweight-bearing joints, suggesting that, in addition to local overload, systemic factors may contribute to joint damage. In this review we summarize the current knowledge on experimental models and clinical studies in which adipocytokines were examined in obesity, RA, and OA and discuss the potential of adipocytokines as comorbidity biomarkers for cardiovascular risk.
Background: The introduction of fast-track treatment procedures following cardiac surgery has significantly shortened hospitalisation times in intensive care units (ICU). Readmission to intensive care units is generally considered a negative quality criterion. The aim of this retrospective study is to statistically analyse risk factors and predictors for re-admission to the ICU after a fast-track patient management program.
Methods: 229 operated patients (67 ± 11 years, 75% male, BMI 27 ± 3, 6/2010-5/2011) with use of extracorporeal circulation (70 ± 31 min aortic crossclamping, CABG 62%) were selected for a preoperative fast-track procedure (transfer on the day of surgery to an intermediate care (IMC) unit, stable circulatory conditions, extubated). A uni- and multivariate analysis were performed to identify independent predictors for re-admission to the ICU.
Results: Over the 11-month study period, 36% of all preoperatively declared fast-track patients could not be transferred to an IMC unit on the day of surgery (n = 77) or had to be readmitted to the ICU after the first postoperative day (n = 4). Readmission or ICU stay signifies a dramatic worsening of the patient outcome (mortality 0/10%, mean hospital stay 10.3 ± 2.5/16.5 ± 16.3, mean transfusion rate 1.4 ± 1,7/5.3 ± 9.1). Predicators for failure of the fast-track procedure are a preoperative ASA class > 3, NYHA class > III and an operation time >267 min ± 74. The significant risk factors for a major postoperative event (= low cardiac output and/or mortality and/or renal failure and/or re-thoracotomy and/or septic shock and/or wound healing disturbances and/or stroke) are a poor EF (OR 2.7 CI 95% 0.98-7.6) and the described ICU readmission (OR 0.14 CI95% 0.05-0.36).
Conclusion: Re-admission to the ICU or failure to transfer patients to the IMC is associated with a high loss of patient outcome. The ASA > 3, NYHA class > 3 and operation time >267 minutes are independent predictors of fast track protocol failure.
Among the discussed risk factors for high-titre inhibitor (HRI) development in patients with hemophilia A (HA) are high dose FVIII replacement therapy and use of recombinant FVIII concentrates (rFVIII). The aim of this study was to evaluate the aforementioned risk factors for HRI development in children with hemophilia A ≤2%. About 288 ascertained PUPs (Israel and Germany) were followed after initial HA diagnosis over 200 exposure days. Inhibitor-free survival, hazard ratios (HR), and 95% confidence intervals (CIs) were calculated. Adjustment was performed for factor VIII concentrates, median single dose over the first three months of treatment, first FVIII administration before the age of three months, presence of risk HA gene mutations, “intensive treatment moments” and “year of birth” (proxy for different treatment periods). HRI occurred in 71/288 children (24.7%). In multivariate analysis adjusted for “year of birth”, underlying risk gene mutations (HR/CI: 2.37/1.40–3.99), FVIII dose, measured per one IU increase per kgbw (HR/CI: 1.05/1.04–1.07), and first FVIII administration before the age of three months showed a significant impact on HR development. The risk of HRI development was similar for recombinant or plasmatic FVIII products. Children at risk should be treated with carefully calculated lower dose regimens, adapted to individual bleeding situations.
Background: Hereditary angioedema (HAE), caused by deficiency in C1-inhibitor (C1-INH), leads to unpredictable edema of subcutaneous tissues with potentially fatal complications. As surgery can be a trigger for edema episodes, current guidelines recommend preoperative prophylaxis with C1-INH or attenuated androgens in patients with HAE undergoing surgery. However, the risk of an HAE attack in patients without prophylaxis has not been quantified.
Objectives: This analysis examined rates of perioperative edema in patients with HAE not receiving prophylaxis.
Methods: This was a retrospective analysis of records of randomly selected patients with HAE type I or II treated at the Frankfurt Comprehensive Care Centre. These were examined for information about surgical procedures and the presence of perioperative angioedema.
Results: A total of 331 patients were included; 247 underwent 700 invasive procedures. Of these procedures, 335 were conducted in 144 patients who had not received prophylaxis at the time of surgery. Categories representing significant numbers of procedures were abdominal (n = 113), ENT (n = 71), and gynecological (n = 58) procedures. The rate of documented angioedema without prophylaxis across all procedures was 5.7%; in 24.8% of procedures, the presence of perioperative angioedema could not be excluded, leading to a maximum potential risk of 30.5%. Predictors of perioperative angioedema could not be identified.
Conclusion: The risk of perioperative angioedema in patients with HAE type I or II without prophylaxis undergoing surgical procedures ranged from 5.7% to 30.5% (CI 3.5–35.7%). The unpredictability of HAE episodes supports current international treatment recommendations to consider short-term prophylaxis for all HAE patients undergoing surgery.
The role of the mRNA-binding protein human antigen R (HuR) in stabilization and translation of AU-rich elements (ARE) containing mRNAs is well established. However, the trafficking of HuR and bound mRNA cargo, which comprises a fundamental requirement for the aforementioned HuR functions is only poorly understood. By administering different cytoskeletal inhibitors, we found that the protein kinase Cδ (PKCδ)-triggered accumulation of cytoplasmic HuR by Angiotensin II (AngII) is an actin-myosin driven process functionally relevant for stabilization of ARE-bearing mRNAs. Furthermore, we show that the AngII-induced recruitment of HuR and its bound mRNA from ribonucleoprotein particles to free and cytoskeleton bound polysomes strongly depended on an intact actomyosin cytoskeleton. In addition, HuR allocation to free and cytoskeletal bound polysomes is highly sensitive toward RNase and PPtase and structurally depends on serine 318 (S318) located within the C-terminal RNA recognition motif (RRM3). Conversely, the trafficking of the phosphomimetic HuRS318D, mimicking HuR phosphorylation at S318 by the PKCδ remained PPtase resistant. Co-immunoprecipitation experiments with truncated HuR proteins revealed that the stimulus-induced association of HuR with myosin IIA is strictly RNA dependent and mediated via the RRM3. Our data implicate a microfilament dependent transport of HuR, which is relevant for stimulus-induced targeting of ARE-bearing mRNAs from translational inactive ribonucleoprotein particles to polysomes.
The efficient coding hypothesis posits that sensory systems of animals strive to encode sensory signals efficiently by taking into account the redundancies in them. This principle has been very successful in explaining response properties of visual sensory neurons as adaptations to the statistics of natural images. Recently, we have begun to extend the efficient coding hypothesis to active perception through a form of intrinsically motivated learning: a sensory model learns an efficient code for the sensory signals while a reinforcement learner generates movements of the sense organs to improve the encoding of the signals. To this end, it receives an intrinsically generated reinforcement signal indicating how well the sensory model encodes the data. This approach has been tested in the context of binocular vison, leading to the autonomous development of disparity tuning and vergence control. Here we systematically investigate the robustness of the new approach in the context of a binocular vision system implemented on a robot. Robustness is an important aspect that reflects the ability of the system to deal with unmodeled disturbances or events, such as insults to the system that displace the stereo cameras. To demonstrate the robustness of our method and its ability to self-calibrate, we introduce various perturbations and test if and how the system recovers from them. We find that (1) the system can fully recover from a perturbation that can be compensated through the system's motor degrees of freedom, (2) performance degrades gracefully if the system cannot use its motor degrees of freedom to compensate for the perturbation, and (3) recovery from a perturbation is improved if both the sensory encoding and the behavior policy can adapt to the perturbation. Overall, this work demonstrates that our intrinsically motivated learning approach for efficient coding in active perception gives rise to a self-calibrating perceptual system of high robustness.
Diffusion tensor imaging (DTI) based assessment of white matter fiber tract integrity can support the diagnosis of Alzheimer’s disease (AD). The use of DTI as a biomarker, however, depends on its applicability in a multicenter setting accounting for effects of different MRI scanners. We applied multivariate machine learning (ML) to a large multicenter sample from the recently created framework of the European DTI study on Dementia (EDSD). We hypothesized that ML approaches may amend effects of multicenter acquisition. We included a sample of 137 patients with clinically probable AD (MMSE 20.6±5.3) and 143 healthy elderly controls, scanned in nine different scanners. For diagnostic classification we used the DTI indices fractional anisotropy (FA) and mean diffusivity (MD) and, for comparison, gray matter and white matter density maps from anatomical MRI. Data were classified using a Support Vector Machine (SVM) and a Naïve Bayes (NB) classifier. We used two cross-validation approaches, (i) test and training samples randomly drawn from the entire data set (pooled cross-validation) and (ii) data from each scanner as test set, and the data from the remaining scanners as training set (scanner-specific cross-validation). In the pooled cross-validation, SVM achieved an accuracy of 80% for FA and 83% for MD. Accuracies for NB were significantly lower, ranging between 68% and 75%. Removing variance components arising from scanners using principal component analysis did not significantly change the classification results for both classifiers. For the scanner-specific cross-validation, the classification accuracy was reduced for both SVM and NB. After mean correction, classification accuracy reached a level comparable to the results obtained from the pooled cross-validation. Our findings support the notion that machine learning classification allows robust classification of DTI data sets arising from multiple scanners, even if a new data set comes from a scanner that was not part of the training sample.
RP1 (synonym: MAPRE2, EB2) is a member of the microtubule binding EB1 protein family, which interacts with APC, a key regulatory molecule in the Wnt signalling pathway. While the other EB1 proteins are well characterized the cellular function and regulation of RP1 remain speculative to date. However, recently RP1 has been implicated in pancreatic cancerogenesis. CK2 is a pleiotropic kinase involved in adhesion, proliferation and anti-apoptosis. Overexpression of protein kinase CK2 is a hallmark of many cancers and supports the malignant phenotype of tumor cells. In this study we investigate the interaction of protein kinase CK2 with RP1 and demonstrate that CK2 phosphorylates RP1 at Ser236 in vitro. Stable RP1 expression in cell lines leads to a significant cleavage and down-regulation of N-cadherin and impaired adhesion. Cells expressing a Phospho-mimicking point mutant RP1-ASP236 show a marked decrease of adhesion to endothelial cells under shear stress. Inversely, we found that the cells under shear stress downregulate endogenous RP1, most likely to improve cellular adhesion. Accordingly, when RP1 expression is suppressed by shRNA, cells lacking RP1 display significantly increased cell adherence to surfaces. In summary, RP1 phosphorylation at Ser236 by CK2 seems to play a significant role in cell adhesion and might initiate new insights in the CK2 and EB1 family protein association.
The relationship between achievement of a pathologic complete response (pCR) and favorable long-term outcome varies among breast cancer subtypes. We aimed to highlight which neoadjuvant treatment strategy could be most successful in each breast cancer subtype. A recent FDA meta-analysis on randomized neoadjuvant breast cancer trials suggests that the survival differences of patients with or without a pCR were less pronounced in luminal A-like tumors, despite the overall favorable prognosis of these patients. Moreover, even though the strong prognostic effect of pCR in HER2 positive and TNBC, the NOAH study was the only trial which showed a trend in surrogacy of pCR for long-term outcome in HER2-positive subtype. Results from GeparTrio study suggest that patients with hormone-positive tumors might need a response-guided approach, with either an intensification of treatment in case of an early response or a change to other chemotherapy in case of no early response. Furthermore, data from German neoadjuvant trials confirm that an increasing number of chemotherapy cycles is associated with a higher pCR rate, especially in patients with HER2-positive/hormone-positive tumors. In line with these suggestions, Tryphaena study showed a pCR rate that exceeding the 60% threshold, the highest pCR results presented in a large multicenter study. In TNBC, the highest pCR rate in the German neoadjuvant studies was obtained with the simultaneous application of docetaxel, doxorubicin and cyclophosphamide for 6 cycles. However, as shown in GaparQuinto and NSABP 40 trials, treatment effect in TNBC might be further maximized by adding bevacizumab, and two randomized neoadjuvant trials are expected this year to report data on the efficacy of carboplatin.
Aim: To compare clinical success and complications of uncovered self-expanding metal stents (SEMS) vs covered SEMS (cSEMS) in obstruction of the small bowel.
Methods: Technical success, complications and outcome of endoscopic SEMS or cSEMS placement in tumor related obstruction of the duodenum or jejunum were retrospectively assessed. The primary end points were rates of stent migration and overgrowth. Secondary end points were the effect of concomitant biliary drainage on migration rate and overall survival. The data was analyzed according to the Strengthening the Reporting of Observational Studies in Epidemiology guidelines.
Results: Thirty-two SEMS were implanted in 20 patients. In all patients, endoscopic stent implantation was successful. Stent migration was observed in 9 of 16 cSEMS (56%) in comparison to 0/16 SEMS (0%) implantations (P = 0.002). Stent overgrowth did not significantly differ between the two stent types (SEMS: 3/16, 19%; cSEMS: 2/16, 13%). One cSEMS dislodged and had to be recovered from the jejunum by way of laparotomy. Time until migration between SEMS and cSEMS in patients with and without concomitant biliary stents did not significantly differ (HR = 1.530, 95%CI 0.731-6.306; P = 0.556). The mean follow-up was 57 ± 71 d (range: 1-275 d).
Conclusion: SEMS and cSEMS placement is safe in small bowel tumor obstruction. However, cSEMS is accompanied with a high rate of migration in comparison to uncovered SEMS.
Sequential dosing in chemosensitization : targeting the PI3K/Akt/mTOR pathway in neuroblastoma
(2013)
Breaking resistance to chemotherapy is a major goal of combination therapy in many tumors, including advanced neuroblastoma. We recently demonstrated that increased activity of the PI3K/Akt network is associated with poor prognosis, thus providing an ideal target for chemosensitization. Here we show that targeted therapy using the PI3K/mTOR inhibitor NVP-BEZ235 significantly enhances doxorubicin-induced apoptosis in neuroblastoma cells. Importantly, this increase in apoptosis was dependent on scheduling: while pretreatment with the inhibitor reduced doxorubicin-induced apoptosis, the sensitizing effect in co-treatment could further be increased by delayed addition of the inhibitor post chemotherapy. Desensitization for doxorubicin-induced apoptosis seemed to be mediated by a combination of cell cycle-arrest and autophagy induction, whereas sensitization was found to occur at the level of mitochondria within one hour of NVP-BEZ235 posttreatment, leading to a rapid loss of mitochondrial membrane potential with subsequent cytochrome c release and caspase-3 activation. Within the relevant time span we observed marked alterations in a ~30 kDa protein associated with mitochondrial proteins and identified it as VDAC1/Porin protein, an integral part of the mitochondrial permeability transition pore complex. VDAC1 is negatively regulated by the PI3K/Akt pathway via GSK3β and inhibition of GSK3β, which is activated when Akt is blocked, ablated the sensitizing effect of NVP-BEZ235 posttreatment. Our findings show that cancer cells can be sensitized for chemotherapy induced cell death – at least in part – by NVP-BEZ235-mediated modulation of VDAC1. More generally, we show data that suggest that sequential dosing, in particular when multiple inhibitors of a single pathway are used in the optimal sequence, has important implications for the general design of combination therapies involving molecular targeted approaches towards the PI3K/Akt/mTOR signaling network.
Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide. COPD is caused by chronic exposure to cigarette smoke and/or other environmental pollutants that are believed to induce reactive oxygen species (ROS) that gradually disrupt signalling pathways responsible for maintaining lung integrity. Here we identify the antioxidant protein Sestrin 2 (Sesn2) as a repressor of PDGFRβ signalling and PDGFRβ signalling as an upstream regulator of alveolar maintenance programs. In mice, the mutational inactivation of Sesn2 prevents the development of cigarette-smoke induced pulmonary emphysema by upregulating PDGFRβ expression via a selective accumulation of intracellular superoxide anions (O2-). We also show that SESN2 is overexpressed and PDGFRβ downregulated in the emphysematous lungs of patients with COPD and to a lesser extent in human lungs of habitual smokers without COPD, implicating a negative SESN2/PDGFRβ interrelationship in the pathogenesis of COPD. Taken together, our results imply that SESN2 could serve as both a biomarker and as a drug target in the clinical management of COPD.
Chronic obstructive pulmonary disease (COPD) is a leading cause of morbidity and mortality worldwide. COPD is caused by chronic exposure to cigarette smoke and/or other environmental pollutants that are believed to induce reactive oxygen species (ROS) that gradually disrupt signalling pathways responsible for maintaining lung integrity. Here we identify the antioxidant protein sestrin-2 (SESN2) as a repressor of PDGFRβ signalling, and PDGFRβ signalling as an upstream regulator of alveolar maintenance programmes. In mice, the mutational inactivation of Sesn2 prevents the development of cigarette-smoke-induced pulmonary emphysema by upregulating PDGFRβ expression via a selective accumulation of intracellular superoxide anions (O2−). We also show that SESN2 is overexpressed and PDGFRβ downregulated in the emphysematous lungs of individuals with COPD and to a lesser extent in human lungs of habitual smokers without COPD, implicating a negative SESN2-PDGFRβ interrelationship in the pathogenesis of COPD. Taken together, our results imply that SESN2 could serve as both a biomarker and as a drug target in the clinical management of COPD.
Men and women differ substantially regarding height, weight, and body fat. Interestingly, previous work detecting genetic effects for waist-to-hip ratio, to assess body fat distribution, has found that many of these showed sex-differences. However, systematic searches for sex-differences in genetic effects have not yet been conducted. Therefore, we undertook a genome-wide search for sexually dimorphic genetic effects for anthropometric traits including 133,723 individuals in a large meta-analysis and followed promising variants in further 137,052 individuals, including a total of 94 studies. We identified seven loci with significant sex-difference including four previously established (near GRB14/COBLL1, LYPLAL1/SLC30A10, VEGFA, ADAMTS9) and three novel anthropometric trait loci (near MAP3K1, HSD17B4, PPARG), all of which were significant in women, but not in men. Of interest is that sex-difference was only observed for waist phenotypes, but not for height or body-mass-index. We found no evidence for sex-differences with opposite effect direction for men and women. The PPARG locus is of specific interest due to its link to diabetes genetics and therapy. Our findings demonstrate the importance of investigating sex differences, which may lead to a better understanding of disease mechanisms with a potential relevance to treatment options.
In zahlreichen, in der Einleitung bereits näher beschriebenen Studien konnte anxiolytische Wirksamkeit des patentierten ätherischen Öls Silexan sowohl im Tiermodell, als auch am Menschen zur Therapie subsyndromaler und generalisierter Angsterkrankungen demonstriert werden.
Das Ziel der vorliegenden Dissertation war es, den zugrunde liegenden pharmakologischen Wirkmechanismus zu untersuchen. Nach eingehender Analyse der Targets klassischer Anxiolytika, richtete sich der Fokus auf spannungsabhängige Calciumkanäle, die die Bindungsstelle des Gabapentinoids Pregabalin enthalten. Die mögliche Modulation der Kanäle wurde an PC-Zellen, einem Modell neuronaler Vorläuferzellen, murinen Synaptosomen, aber auch in primären Neuronen der für die Genese der Angsterkrankungen relevanten Hirnareale Hippocampus und Cortex untersucht. Die Kanalexpression, sowie - distribution in den unterschiedlichen Geweben wurde charakterisiert und die Frage erörtert, ob Silexan spezifische Modulation eines bestimmten Kanalsubtyps vermittelt oder unspezifisch alle Kanäle dieser Gattung inhibiert. Um dies näher zu beleuchten wurden elektrophysiologische Messungen an transfizierten Zellen durchgeführt, die jeweils nur einen Subtyp der Familie spannungsabhängiger Calciumkanäle exprimieren. Zur weiteren Aufklärung des Wirkmechanismus wurde auch die mögliche Involvierung G-Protein gekoppelter Rezeptoren ermittelt.
Der zweite Teil der vorliegenden Untersuchung widmet sich der Klärung potentieller antidepressiver Wirkungen durch mögliche neurotrophe Effekte. Primäre hippocampale Neurone und PC12-Zellen wurden hierzu u.a. auf prä- und postsynaptische Marker, Ausdifferenzierungsmarker, sowie Neuritenwachstum hin analysiert.
Human deep sleep is characterized by reduced sensory activity, responsiveness to stimuli, and conscious awareness. Given its ubiquity and reversible nature, it represents an attractive paradigm to study the neural changes which accompany the loss of consciousness in humans. In particular, the deepest stages of sleep can serve as an empirical test for the predictions of theoretical models relating the phenomenology of consciousness with underlying neural activity. A relatively recent shift of attention from the analysis of evoked responses toward spontaneous (or “resting state”) activity has taken place in the neuroimaging community, together with the development of tools suitable to study distributed functional interactions. In this review we focus on recent functional Magnetic Resonance Imaging (fMRI) studies of spontaneous activity during sleep and their relationship with theoretical models for human consciousness generation, considering the global workspace theory, the information integration theory, and the dynamical core hypothesis. We discuss the venues of research opened by these results, emphasizing the need to extend the analytic methodology in order to obtain a dynamical picture of how functional interactions change over time and how their evolution is modulated during different conscious states. Finally, we discuss the need to experimentally establish absent or reduced conscious content, even when studying the deepest sleep stages.
Evasion of apoptosis, for example, by inhibitor of apoptosis (IAP) proteins, contributes to treatment resistance and poor outcome in acute myeloid leukemia (AML). Here we identify a novel synergistic interaction between the small-molecule second mitochondria-derived activator of caspases (Smac) mimetic BV6, which antagonizes X-linked IAP, cellular IAP (cIAP)1 and cIAP2, and the demethylating agents 5-azacytidine or 5-aza-2′-deoxycytidine (DAC) to induce cell death in AML cells, including apoptosis-resistant cells. Calculation of combination index (CI) confirms that this drug combination is highly synergistic (CI 0.02–0.4). In contrast, BV6 and DAC at equimolar concentrations do not cause synergistic toxicity against normal peripheral blood lymphocytes, pointing to some tumor cell selectivity. Molecular studies reveal that BV6 and DAC cooperate to trigger the activation of caspases, mitochondrial perturbations and DNA fragmentation, consistent with apoptotic cell death. However, the broad-range caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (zVAD.fmk) fails to protect against BV6/DAC-induced cell death and even significantly increases the percentage of Annexin-V/propidium iodide double-positive cells. Importantly, BV6/DAC-induced cell death in the presence of zVAD.fmk is significantly reduced by pharmacological inhibition of key components of necroptosis signaling, that is, receptor-interacting protein (RIP) 1 using necrostatin-1 or mixed lineage kinase domain-like protein (MLKL) using necrosulfonamide. This indicates a switch from BV6/DAC-induced cell death from apoptosis to necroptosis upon caspase inhibition. Thus, BV6 cooperates with demethylating agents to induce cell death in AML cells and circumvents apoptosis resistance via a switch to necroptosis as an alternative mode of cell death. The identification of a novel synergism of BV6 and demethylating agents has important implications for the development of new treatment strategies for AML.
Small bowel endoscopy is indicated for patients with an unidentified bleeding site in esophago-gastro-duodenoscopy and ileo-colonoscopy 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. In few cases, though, lesions outside of the small bowel might be revealed by CE. Therefore, attention to all intestines that are visualized by CE might be necessary not to overlook bleeding sites that had not been discovered by prior flexible endoscopy.
The authors present the case of a 71-year-old male patient who presented to their outpatient clinic for unexplained anemia. Small bowel CE revealed minor bleeding from an adenocarcinoma in the cecum. This article is part of an expert video encyclopedia.
This is the case report of a 58-year-old male patient who presented with recurring abdominal pain of 4 months duration. He had undergone multiple investigations including upper and lower gastrointestinal tract endoscopies and diagnostic laparoscopy, but there were no significant findings detected.
Capsule endoscopy revealed a submucosal small bowel tumor that was suspected to originate from the distal third of the small bowel. Surgery was indicated and a highly differentiated neuroendocrine tumor was found at laparotomy at the distal ileum. An ileocecal resection was performed confirming a neuroendocrine tumor of the small bowel (G2T2N1M1). This article is part of an expert video encyclopedia.
In this article, the video demonstrated is an example of a 76-year-old male patient who presented with recurrent intestinal bleeding of unknown origin at the university hospital. Previously performed upper and lower gastrointestinal tract endoscopy did not reveal a bleeding lesion. Capsule endoscopy revealed small-bowel angiectasia that were treated by argon plasma coagulation at subsequent balloon enteroscopy. This article is part of an expert video encyclopedia.
Smoking cigarettes throughout pregnancy is one of the single most important avoidable causes of adverse pregnancy outcomes and it represents the first major environmental risk of the unborn. If compared with other risk factors in the perinatal period, exposure to tobacco smoke is considered to be amongst the most harmful and it is associated with high rates of long and short term morbidity and mortality for mother and child. A variety of adverse pregnancy outcomes are linked with cigarette consumption before and during pregnancy. Maternal prenatal cigarette smoke disturbs the equilibrium among the oxidant and antioxidant system, has negative impact on the genetic and cellular level of both mother and fetus and causes a large quantity of diseases in the unborn child. These smoking-induced damages for the unborn offspring manifest themselves at various times in life and for most only a very limited range of causal treatment exists. Education, support and assistance are of high importance to decrease maternal and fetal morbidity and mortality, as there are few other avoidable factors which influence a child's health that profoundly throughout its life. It is imperative that smoking control should be seen as a public health priority.
Smoking tobacco throughout pregnancy is one of the single most important avoidable causes of adverse pregnancy outcomes. If compared with other risk factors in the perinatal period, exposure to tobacco smoke is considered to be amongst the most harmful. It is associated with high rates of long and short term morbidity and mortality for mother and child. Despite this importance until now a scientometric analysis about the development and the state of scientific knowledge about smoking and pregnancy has not been published. In order to close this gap this work was conceived. In this dissertation quantitative and qualitative data on this topic was analyzed using a variety of objective scientometric methods like the number of scientific contributions, the number of citations and the modified Hirsch-index (H-index). A collective volume of 10,043 entries covering a time period from 1900 to December 5, 2012 was obtained from the Web of Science (WoS) data base. Publishing activities of authors, institutions and countries, their cooperation, reception within the international scientific community and its reactions were interpreted and illustrated.
Aim: The aim of this study was to measure cortico-cortical connectivity in multiple sclerosis (MS) patients by TMS-evoked potential (TEP) latencies in EEG evoked by transcranial magnetic stimulation (TMS) of the hand area of the primary motor cortex of one hemisphere. TEPs were recorded on the stimulated- and at the homologue site in the non-stimulated contralateral hemisphere. Both interhemispheric directions were tested. Interhemispheric latencies of the two main reproducible TEPs, the positive component at 60 ms and the negative component at 100 ms (P60 and N100, respectively), were expected to be significantly prolonged in MS-patients compared to healthy volunteers.
Material and methods: The study compared interhemispheric propagation of P60 and N100 in groups of 12 patients with early-stage relapsing-remitting MS (RRMS) and 16 age- and gender-matched healthy controls. The study was approved by the Ethics Committee of the Medical Faculty of the Goethe-University of Frankfurt/Main and conformed to the latest revision of the Declaration of Helsinki of 2008. TEPs were recorded by means of EEG and their latencies were statistically evaluated in 10 channels around the stimulation site and in 10 corresponding electrodes in the non-stimulated contralateral hemisphere. Interhemispheric conduction time was calculated by the difference of TEP latency in non-stimulated vs. stimulated hemisphere.
Results: An ANOVA on interhemispheric conduction time showed a significant prolongation for the N100 from left to right hemisphere in MS compared to controls, while no group differences were found for the P60 and the N100 from right to left hemisphere.
Conclusion: The results provide first evidence that the N100 may constitute an interesting marker to measure interhemispheric conduction delays in early-stage RRMS. The specificity of the present finding and its relation to fiber tract pathology should be examined in further correlative analyses with diffusion tensor imaging and other structural MRI data.
In the current event-related potential (ERP) study, we investigated how speech rhythm impacts speech segmentation and facilitates the resolution of syntactic ambiguities in auditory sentence processing. Participants listened to syntactically ambiguous German subject- and object-first sentences that were spoken with either regular or irregular speech rhythm. Rhythmicity was established by a constant metric pattern of three unstressed syllables between two stressed ones that created rhythmic groups of constant size. Accuracy rates in a comprehension task revealed that participants understood rhythmically regular sentences better than rhythmically irregular ones. Furthermore, the mean amplitude of the P600 component was reduced in response to object-first sentences only when embedded in rhythmically regular but not rhythmically irregular context. This P600 reduction indicates facilitated processing of sentence structure possibly due to a decrease in processing costs for the less-preferred structure (object-first). Our data suggest an early and continuous use of rhythm by the syntactic parser and support language processing models assuming an interactive and incremental use of linguistic information during language processing.
Because of its highly bioactive properties sphingosine 1-phosphate (S1P) is an attractive target for the treatment of several diseases. Since the expression of sphingosine kinases as well as S1P receptors was demonstrated in the kidney, questions about the physiological and pathophysiological functions of S1P in this organ have been raised. In this review, we summarize the current state of knowledge about S1P-mediated functions in the kidney. A special focus is put on S1P modulated signal transduction in renal glomerular and tubular cells and consequences for the development and treatment of several kidney diseases, diabetic nephropathy, glomerulonephritis, ischemia-reperfusion injury, as well as for Wilms tumor progression.
Das Medizinstudium und die spätere Berufstätigkeit werden als stressig angesehen; dennoch liegen nur wenige Daten zur Stressbelastung von Medizinstudenten und Ärzten vor. Als Teil einer umfangreichen Erhebung zur Stressbelastung haben wir die Stressbelastung und Resilienz von Frankfurter Medizinstudenten in den ersten Wochen des 1. vorklinischen Semesters erhoben (Trierer Inventar zum chronischen Stress TICS, Resilienz-Skala RS11); an der Studie nahmen 348 von 383 Studienanfängern (90,8%) teil. Übereinstimmend mit Ergebnissen aus dem 5. Semester zeigen die Studenten des 1. Semesters hohe Werte insbesondere in den Teilskalen Überlastung und Überforderung; auffallend sind ebenfalls hohe Werte in den Skalen Soziale Isolation und Summenscore. Ein T-Score (altersnormierter Normalwert = 50) über der 2fachen Vertrauensgrenze findet sich im Summenscore (17,2%), chronische Besorgnis (17,8%), Überforderung (11,2%) und Überlastung (22,7%), während in anderen Skalen entsprechende Werte nur bei 1–5% der Teilnehmer erreicht wurden. Die Skalen Überlastung, Erfolgsdruck, chronische Besorgnis sowie der Summenscore sind weitgehend normalverteilt (Schiefe <0,2), dieser Wert beträgt für die anderen Skalen 0,45–0,65. Zwischen den Unterskalen finden sich Korrelationskoeffizienten >0,5 für Überlastung und Überforderung sowie chronischer Besorgnis, zwischen Überforderung und mangelnder sozialer Anerkennung, sozialer Isolierung und chronischer Besorgnis sowie zwischen sozialen Spannungen, sozialer Isolierung und chronischer Besorgnis. Parallel wurde die Resilienz mit Hilfe des Fragebogens RS11 erhoben (kein Optimum, hohe Werte weisen auf Resilienz hin). Bei einer Maximalpunktzahl von 77 erreichten die Studenten 62,2 +/– 8,8 Punkte, bei einer ausgeprägten rechtsschiefen Verteilung. Zwischen der Stressbelastung und der Resilienz fand sich keine relevante Korrelation, mit einem Maximalwert von –0,267 zwischen dem RS11-Score und der Subskala Überforderung. Die Daten belegen ein bereits zu Studienbeginn vorliegendes hohes Maß an Überlastung und Überforderung; dieser Stress korreliert nicht mit der Fähigkeit, mit Stress adäquat umzugehen (Resilienz).
Medizinstudium, Examina und die Berufstätigkeit sind stressig; belastbare Daten zum allgemeinen und spezifischen Stress während des Medizinstudiums liegen nur in geringem Ausmaß vor. Wir haben die Stressbelastung und Resilienz der Frankfurter Medizinstudenten in den Kohorten 1. vorklinisches Semester, 1. klinisches Semester und PJ-Eintritt erhoben (Trierer Inventar zum chronischen Stress TICS, altersnormierter Mittelwert = 50; Resilienz-Skala RS11, kein Optimum, hohe Werte weisen auf Resilienz hin); an der Studie nahmen jeweils mehr als 90% der entsprechenden Kohorte teil. Während zu Studienbeginn der Summenwert (altersnormierter T-Wert) bei 56% lag, fiel dieser im 1. klin. Semester auf 54%, und stieg zum PJ nur gering wieder an. Unter den Subskalen fiel auf, dass Überlastung, Überforderung und chronische Besorgnis parallel zum Gesamtscore abfielen, die Subskala Unzufriedenheit jedoch zunahm (1. vorklin. Semester 53%, 1. klin. Semester 55%, PJ 58%). Die höchsten Werte in der PJ-Gruppe fanden sich ebenfalls für die Subskalen soziale Überlastung, Mangel an sozialer Anerkennung und Soziale Spannungen. Niedrigere Stressskala-Werte zeigten sich nach dem Staatsexamen M1 in den Subskalen Überlastung, Erfolgsdruck, Überforderung, soziale Isolierung, chronische Besorgnis und dem Summenscore. Überraschenderweise fiel der Summenwert der Resilienz vom 1. vorklinischen und 1. klinischen Semester (80,7%) auf 76,7% vor dem PJ-Eintritt, dieser Abfall zeigte sich für alle 11 Einzelitems dieses Fragebogens in gleicher Weise. Während eine Abnahme der Belastungsabhängigen Skalen Überlastung und Überforderung nach dem Staatsexamen M1 erwartet worden war, überraschte die im Gruppenvergleich abnehmende Resilienz bei den Studenten vor dem Praktischen Jahr. Ebenso überraschend war die fast kontinuierliche Zunahme auf der Subskala Unzufriedenheit während des Studiums. Inwieweit diese Differenzen auf das Studium zurückzuführen sind oder auf eine überzufällige Häufung bei den Studienabbrechern, wird in einer prospektiven Fortführung dieser Studie untersucht.
Background: Hepatitis B coinfection is common in HIV-positive individuals and as antiretroviral therapy has made death due to AIDS less common, hepatitis has become increasingly important. Several drugs are available to treat hepatitis B. The most potent and the one with the lowest risk of resistance appears to be tenofovir (TDF). However there are several questions that remain unanswered regarding the use of TDF, including the proportion of patients that achieves suppression of HBV viral load and over what time, whether suppression is durable and whether prior treatment with other HBV-active drugs such as lamivudine, compromises the efficacy of TDF due to possible selection of resistant HBV strains.
Methods: A systematic review and meta-analysis following PRISMA guidelines and using multilevel mixed effects logistic regression, stratified by prior and/or concomitant use of lamivudine and/or emtricitabine.
Results: Data was available from 23 studies including 550 HBV/HIV coinfected patients treated with TDF. Follow up was for up to seven years but to ensure sufficient power the data analyses were limited to three years. The overall proportion achieving suppression of HBV replication was 57.4%, 79.0% and 85.6% at one, two and three years, respectively. No effect of prior or concomitant 3TC/FTC was shown. Virological rebound on TDF treatment was rare.
Interpretation: TDF suppresses HBV to undetectable levels in the majority of HBV/HIV coinfected patients with the proportion fully suppressed continuing to increase during continuous treatment. Prior treatment with 3TC/FTC does not compromise efficacy of TDF treatment. The use of combination treatment with 3TC/FTC offers no significant benefit over TDF alone.
Objectives Tumour recurrence of glioblastoma multiforme (GBM) after initial treatment with surgical resection, radiotherapy and chemotherapy is an inevitable phenomenon. This retrospective cohort study compared the efficacy of interstitial high dose rate brachytherapy (HDR-BRT), re-resection and sole dose dense temozolomide chemotherapy (ddTMZ) in the treatment of recurrent glioblastoma after initial surgery and radiochemotherapy.
Design Retropective cohort study.
Setting Primary level of care with two participating centres. The geographical location was central Germany.
Participants From January 2005 to December 2010, a total of 111 patients developed recurrent GBM after initial surgery and radiotherapy with concomitant temozolomide. The inclusion criteria were as follows: (1) histology-proven diagnosis of primary GBM (WHO grade 4), (2) primary treatment with resection and radiochemotherapy, and (3) tumour recurrence/progression.
Interventions This study compared retrospectively the efficacy of interstitial HDR-BRT, re-resection and ddTMZ alone in the treatment of recurrent glioblastoma.
Primary and secondary outcome measures Median survival, progression free survival and complication rate.
Results Median survival after salvage therapy of the recurrence was 37, 30 and 26 weeks, respectively. The HDR-BRT group did significantly better than both the reoperation (p<0.05) and the ddTMZ groups (p<0.05). Moderate to severe complications in the HDR-BRT, reoperation and sole chemotherapy groups occurred in 5/50 (10%), 4/36 (11%) and 9/25 (36%) cases, respectively.
Conclusions CT-guided interstitial HDR-BRT attained higher survival benefits in the management of recurrent glioblastoma after initial surgery and radiotherapy with concurrent temozolomide in comparison with the other treatment modalities. The low risk of complications of the HDR-BRT and the fact that it can be delivered percutaneously in local anaesthesia render it a promissing treatment option for selected patients which should be further evaluated.
To truly appreciate the myriad of events which relate synaptic function and vesicle dynamics, simulations should be done in a spatially realistic environment. This holds true in particular in order to explain as well the rather astonishing motor patterns which we observed within in vivo recordings which underlie peristaltic contractionsas well as the shape of the EPSPs at different forms of long-term stimulation, presented both here, at a well characterized synapse, the neuromuscular junction (NMJ) of the Drosophila larva (c.f. Figure 1). To this end, we have employed a reductionist approach and generated three dimensional models of single presynaptic boutons at the Drosophila larval NMJ. Vesicle dynamics are described by diffusion-like partial differential equations which are solved numerically on unstructured grids using the uG platform. In our model we varied parameters such as bouton-size, vesicle output probability (Po), stimulation frequency and number of synapses, to observe how altering these parameters effected bouton function. Hence we demonstrate that the morphologic and physiologic specialization maybe a convergent evolutionary adaptation to regulate the trade off between sustained, low output, and short term, high output, synaptic signals. There seems to be a biologically meaningful explanation for the co-existence of the two different bouton types as previously observed at the NMJ (characterized especially by the relation between size and Po), the assigning of two different tasks with respect to short- and long-time behaviour could allow for an optimized interplay of different synapse types. We can present astonishing similar results of experimental and simulation data which could be gained in particular without any data fitting, however based only on biophysical values which could be taken from different experimental results. As a side product, we demonstrate how advanced methods from numerical mathematics could help in future to resolve also other difficult experimental neurobiological issues.
Peripheral sensitization during inflammatory pain is mediated by a variety of endogenous proalgesic mediators including a number of oxidized lipids, some of which serve endogenous modulators of sensory TRP-channels. These lipids are eicosanoids of the arachidonic acid and linoleic acid pathway, as well as lysophophatidic acids (LPAs). However, their regulation pattern during inflammatory pain and their contribution to peripheral sensitization is still unclear. Here, we used the UVB-model for inflammatory pain to investigate alterations of lipid concentrations at the site of inflammation, the dorsal root ganglia (DRGs) as well as the spinal dorsal horn and quantified 21 lipid species from five different lipid families at the peak of inflammation 48 hours post irradiation. We found that known proinflammatory lipids as well as lipids with unknown roles in inflammatory pain to be strongly increased in the skin, whereas surprisingly little changes of lipid levels were seen in DRGs or the dorsal horn. Importantly, although there are profound differences between the number of cytochrome (CYP) genes between mice and rats, CYP-derived lipids were regulated similarly in both species. Since TRPV1 agonists such as LPA 18:1, 9- and 13-HODE, 5- and 12-HETE were elevated in the skin, they may contribute to thermal hyperalgesia and mechanical allodynia during UVB-induced inflammatory pain. These results may explain why some studies show relatively weak analgesic effects of cyclooxygenase inhibitors in UVB-induced skin inflammation, as they do not inhibit synthesis of other proalgesic lipids such as LPA 18:1, 9-and 13-HODE and HETEs.
We report here the effects of temperature on the p1 neuromuscular system of the stomatogastric system of the lobster (Panulirus interruptus). Muscle force generation, in response to both the spontaneously rhythmic in vitro pyloric network neural activity and direct, controlled motor nerve stimulation, dramatically decreased as temperature increased, sufficiently that stomach movements would very unlikely be maintained at warm temperatures. However, animals fed in warm tanks showed statistically identical food digestion to those in cold tanks. Applying dopamine, a circulating hormone in crustacea, increased muscle force production at all temperatures and abolished neuromuscular system temperature dependence. Modulation may thus exist not only to increase the diversity of produced behaviors, but also to maintain individual behaviors when environmental conditions (such as temperature) vary.
This is an example of capsule endoscopy (CE) revealing terminal ileitis in an young male patient with recurrent abdominal pain who had previously been investigated with colonoscopy and esophagogastroduodenoscopy without any significant findings. CE revealed severe inflammation of the terminal ileum. This article is part of an expert video encyclopedia.
Novel treatment options are needed for the successful therapy of patients with high-risk neuroblastoma. Here, we investigated the cyclin-dependent kinase (CDK) inhibitor SNS-032 in a panel of 109 neuroblastoma cell lines consisting of 19 parental cell lines and 90 sublines with acquired resistance to 14 different anticancer drugs. Seventy-three percent of the investigated neuroblastoma cell lines and all four investigated primary tumor samples displayed concentrations that reduce cell viability by 50% in the range of the therapeutic plasma levels reported for SNS-032 (<754 nM). Sixty-two percent of the cell lines and two of the primary samples displayed concentrations that reduce cell viability by 90% in this concentration range. SNS-032 also impaired the growth of the multidrug-resistant cisplatin-adapted UKF-NB-3 subline UKF-NB-3rCDDP1000 in mice. ABCB1 expression (but not ABCG2 expression) conferred resistance to SNS-032. The antineuroblastoma effects of SNS-032 did not depend on functional p53. The antineuroblastoma mechanism of SNS-032 included CDK7 and CDK9 inhibition-mediated suppression of RNA synthesis and subsequent depletion of antiapoptotic proteins with a fast turnover rate including X-linked inhibitor of apoptosis (XIAP), myeloid cell leukemia sequence 1 (Mcl-1), baculoviral IAP repeat containing 2 (BIRC2; cIAP-1), and survivin. In conclusion, CDK7 and CDK9 represent promising drug targets and SNS-032 represents a potential treatment option for neuroblastoma including therapy-refractory cases.
Background: Characterisation of risk groups who may benefit from pneumococcal vaccination is essential for the generation of recommendations and policy.
Methods: We reviewed the literature to provide information on the incidence and risk of invasive pneumococcal disease (IPD) in at-risk children in Europe and North America. The PubMed database was searched using predefined search terms and inclusion/exclusion criteria for papers reporting European or North American data on the incidence or risk of IPD in children with underlying medical conditions.
Results: Eighteen references were identified, 11 from North America and 7 from Europe, with heterogeneous study methods, periods and populations. The highest incidence was seen in US children positive for human immunodeficiency virus infection, peaking at 4167 per 100,000 patient-years in 2000. Studies investigating changes in incidence over time reported decreases in the incidence of IPD between the late 1990s and early 2000s. The highest risk of IPD was observed in children with haematological cancers or immunosuppression. Overall, data on IPD in at-risk children were limited, lacking incidence data for a wide range of predisposing conditions. There was, however, a clear decrease in the incidence of IPD in at-risk children after the introduction of 7-valent pneumococcal conjugate vaccine into immunisation programmes, as previously demonstrated in the general population.
Conclusion: Despite the heterogeneity of the studies identified, the available data show a substantial incidence of IPD in at-risk children, particularly those who are immunocompromised. Further research is needed to determine the true risk of IPD in at-risk children, particularly in the post-PCV period, and to understand the benefits of vaccination and optimal vaccination schedules.
Many snake venoms are known for their antithrombotic activity. They contain components that specifically target different platelet-activating receptors such as the collagen-binding integrin α2β1 and the von Willebrand factor receptor GPIb. In a search for an α2β1 integrin-blocking component from the venom of the habu snake (Trimeresurus flavoviridis), we employed two independent purification protocols. First, we used the integrin α2A domain, a major collagen-binding domain, as bait for affinity purification of an α2β1 integrin-binding toxin from the crude venom. Second, in parallel, we used classical protein separation protocols and tested for α2β1 integrin-inhibiting capabilities by ELISA. Using both approaches, we identified flavocetin-A as an inhibitor of α2β1 integrin. Hitherto, flavocetin-A has been reported as a GPIb inhibitor. However, flavocetin-A inhibited collagen-induced platelet aggregation even after GPIb was blocked with other inhibitors. Moreover, flavocetin-A antagonized α2β1 integrin-mediated adhesion and migration of HT1080 human fibrosarcoma cells, which lack any GPIb, on collagen. Protein chemical analyses proved that flavocetin-A binds to α2β1 integrin and its α2A domain with high affinity and in a cooperative manner, which most likely is due to its quaternary structure. Kinetic measurements confirmed the formation of a strong complex between integrin and flavocetin-A, which dissociates very slowly. This study proves that flavocetin-A, which has long been known as a GPIb inhibitor, efficiently targets α2β1 integrin and thus blocks collagen-induced platelet activation. Moreover, our findings suggest that the separation of GPIb- and α2β1 integrin-blocking members within the C-type lectin-related protein family is less strict than previously assumed.