Medizin
Refine
Year of publication
Document Type
- Article (3563) (remove)
Has Fulltext
- yes (3563)
Is part of the Bibliography
- no (3563) (remove)
Keywords
- inflammation (47)
- glioblastoma (29)
- apoptosis (27)
- breast cancer (26)
- cancer (26)
- Inflammation (19)
- biomarker (18)
- COVID-19 (17)
- autophagy (17)
- Depression (15)
Institute
- Medizin (3563) (remove)
The large conductance voltage- and Ca2+-activated potassium (BK) channel has been suggested to play an important role in the signal transduction process of cochlear inner hair cells. BK channels have been shown to be composed of the pore-forming alpha-subunit coexpressed with the auxiliary beta-1-subunit. Analyzing the hearing function and cochlear phenotype of BK channel alpha-(BKalpha–/–) and beta-1-subunit (BKbeta-1–/–) knockout mice, we demonstrate normal hearing function and cochlear structure of BKbeta-1–/– mice. During the first 4 postnatal weeks also, BKalpha–/– mice most surprisingly did not show any obvious hearing deficits. High-frequency hearing loss developed in BKalpha–/– mice only from ca. 8 weeks postnatally onward and was accompanied by a lack of distortion product otoacoustic emissions, suggesting outer hair cell (OHC) dysfunction. Hearing loss was linked to a loss of the KCNQ4 potassium channel in membranes of OHCs in the basal and midbasal cochlear turn, preceding hair cell degeneration and leading to a similar phenotype as elicited by pharmacologic blockade of KCNQ4 channels. Although the actual link between BK gene deletion, loss of KCNQ4 in OHCs, and OHC degeneration requires further investigation, data already suggest human BK-coding slo1 gene mutation as a susceptibility factor for progressive deafness, similar to KCNQ4 potassium channel mutations. © 2004, The National Academy of Sciences. Freely available online through the PNAS open access option.
Background: The existence of a constitutively expressed machinery for death in individual cells has led to the notion that survival factors repress this machinery and, if such factors are unavailable, cells die by default. In many cells, however, mRNA and protein synthesis inhibitors induce apoptosis, suggesting that in some cases transcriptional activity might actually impede cell death. To identify transcriptional mechanisms that interfere with cell death and survival, we combined gene trap mutagenesis with site-specific recombination (Cre/loxP system) to isolate genes from cells undergoing apoptosis by growth factor deprivation.
Results: From an integration library consisting of approximately 2 × 106 unique proviral integrations obtained by infecting the interleukin-3 (IL-3)-dependent hematopoietic cell line - FLOXIL3 - with U3Cre gene trap virus, we have isolated 125 individual clones that converted to factor independence upon IL-3 withdrawal. Of 102 cellular sequences adjacent to U3Cre integration sites, 17% belonged to known genes, 11% matched single expressed sequence tags (ESTs) or full cDNAs with unknown function and 72% had no match within the public databases. Most of the known genes recovered in this analysis encoded proteins with survival functions.
Conclusions: We have shown that hematopoietic cells undergoing apoptosis after withdrawal of IL-3 activate survival genes that impede cell death. This results in reduced apoptosis and improved survival of cells treated with a transient apoptotic stimulus. Thus, apoptosis in hematopoietic cells is the end result of a conflict between death and survival signals, rather than a simple death by default.
An excess of the proinflammatory substance IL-18 is present in joints of patients with rheumatoid arthritis (RA), and expression of IL-18 receptor (IL-18R) regulates IL-18 bioactivity in various cell types. We examined the expression of IL-18R alpha-chain and beta-chain and the biologic effects of IL-18 in fibroblast-like synoviocytes (FLS) after long-term culture. The presence of both IL-18R chains was a prerequisite for IL-18 signal transduction in FLS. However, all FLS cultures studied were either resistant or barely responsive to IL-18 stimulation as regards cell proliferation, expression of adhesion molecules ICAM-1 and vascular cell adhesion molecule (VCAM)-1, and the release of interstitial collagenase and stromelysin, IL-6 and IL-8, prostaglandin E2, or nitric oxide. We conclude that the presence of macrophages or IL-18R+ T cells that can respond directly to IL-18 is essential for the proinflammatory effects of IL-18 in synovitis in RA. Open Access: Published: 14 November 2001 © 2002 Möller et al., licensee BioMed Central Ltd (Print ISSN 1465-9905; Online ISSN 1465-9913)
Background: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is performed mainly in patients with high-risk or advanced hematologic malignancies and congenital or acquired aplastic anemias. In the context of the significant risk of graft failure after allo-HSCT from alternative donors and the risk of relapse in recipients transplanted for malignancy, the precise monitoring of posttransplant hematopoietic chimerism is of utmost interest. Useful molecular methods for chimerism quantification after allogeneic transplantation, aimed at distinguishing precisely between donor's and recipient's cells, are PCR-based analyses of polymorphic DNA markers. Such analyses can be performed regardless of donor's and recipient's sex. Additionally, in patients after sex-mismatched allo-HSCT, fluorescent in situ hybridization (FISH) can be applied. Methods: We compared different techniques for analysis of posttransplant chimerism, namely FISH and PCR-based molecular methods with automated detection of fluorescent products in an ALFExpress DNA Sequencer (Pharmacia) or ABI 310 Genetic Analyzer (PE). We used Spearman correlation test. Results: We have found high correlation between results obtained from the PCR/ALF Express and PCR/ABI 310 Genetic Analyzer. Lower, but still positive correlations were found between results of FISH technique and results obtained using automated DNA sizing technology. Conclusions: All the methods applied enable a rapid and accurate detection of post-HSCT chimerism.
Background: To investigate the occupational risk of tuberculosis (TB) infection in a low-incidence setting, data from a prospective study of patients with culture-confirmed TB conducted in Hamburg, Germany, from 1997 to 2002 were evaluated. Methods: M. tuberculosis isolates were genotyped by IS6110 RFLP analysis. Results of contact tracing and additional patient interviews were used for further epidemiological analyses. Results: Out of 848 cases included in the cluster analysis, 286 (33.7%) were classified into 76 clusters comprising 2 to 39 patients. In total, two patients in the non-cluster and eight patients in the cluster group were health-care workers. Logistic regression analysis confirmed work in the health-care sector as the strongest predictor for clustering (OR 17.9). However, only two of the eight transmission links among the eight clusters involving health-care workers had been detected previously. Overall, conventional contact tracing performed before genotyping had identified only 26 (25.2%) of the 103 contact persons with the disease among the clustered cases whose transmission links were epidemiologically verified. Conclusion: Recent transmission was found to be strongly associated with health-care work in a setting with low incidence of TB. Conventional contact tracing alone was shown to be insufficient to discover recent transmission chains. The data presented also indicate the need for establishing improved TB control strategies in health-care settings.
Introduction: ScFv(FRP5)-ETA is a recombinant antibody toxin with binding specificity for ErbB2 (HER2). It consists of an N-terminal single-chain antibody fragment (scFv), genetically linked to truncated Pseudomonas exotoxin A (ETA). Potent antitumoral activity of scFv(FRP5)-ETA against ErbB2-overexpressing tumor cells was previously demonstrated in vitro and in animal models. Here we report the first systemic application of scFv(FRP5)-ETA in human cancer patients.
Methods: We have performed a phase I dose-finding study, with the objective to assess the maximum tolerated dose and the dose-limiting toxicity of intravenously injected scFv(FRP5)-ETA. Eighteen patients suffering from ErbB2-expressing metastatic breast cancers, prostate cancers, head and neck cancer, non small cell lung cancer, or transitional cell carcinoma were treated. Dose levels of 2, 4, 10, 12.5, and 20 μg/kg scFv(FRP5)-ETA were administered as five daily infusions each for two consecutive weeks.
Results: No hematologic, renal, and/or cardiovascular toxicities were noted in any of the patients treated. However, transient elevation of liver enzymes was observed, and considered dose limiting, in one of six patients at the maximum tolerated dose of 12.5 μg/kg, and in two of three patients at 20 μg/kg. Fifteen minutes after injection, peak concentrations of more than 100 ng/ml scFv(FRP5)-ETA were obtained at a dose of 10 μg/kg, indicating that predicted therapeutic levels of the recombinant protein can be applied without inducing toxic side effects. Induction of antibodies against scFv(FRP5)-ETA was observed 8 days after initiation of therapy in 13 patients investigated, but only in five of these patients could neutralizing activity be detected. Two patients showed stable disease and in three patients clinical signs of activity in terms of signs and symptoms were observed (all treated at doses ≥ 10 μg/kg). Disease progression occurred in 11 of the patients.
Conclusion: Our results demonstrate that systemic therapy with scFv(FRP5)-ETA can be safely administered up to a maximum tolerated dose of 12.5 μg/kg in patients with ErbB2-expressing tumors, justifying further clinical development.
Dendritic cells (DC) are known to present exogenous protein Ag effectively to T cells. In this study we sought to identify the proteases that DC employ during antigen processing. The murine epidermal-derived DC line Xs52, when pulsed with PPD, optimally activated the PPD-reactive Th1 clone LNC.2F1 as well as the Th2 clone LNC.4k1, and this activation was completely blocked by chloroquine pretreatment. These results validate the capacity of XS52 DC to digest PPD into immunogenic peptides inducing antigen specific T cell immune responses. XS52 DC, as well as splenic DC and DCs derived from bone marrow degraded standard substrates for cathepsins B, C, D/E, H, J, and L, tryptase, and chymases, indicating that DC express a variety of protease activities. Treatment of XS52 DC with pepstatin A, an inhibitor of aspartic acid proteases, completely abrogated their capacity to present native PPD, but not trypsin-digested PPD fragments to Th1 and Th2 cell clones. Pepstatin A also inhibited cathepsin D/E activity selectively among the XS52 DC-associated protease activities. On the other hand, inhibitors of serine proteases (dichloroisocoumarin, DCI) or of cystein proteases (E-64) did not impair XS52 DC presentation of PPD, nor did they inhibit cathepsin D/E activity. Finally, all tested DC populations (XS52 DC, splenic DC, and bone marrow-derived DC) constitutively expressed cathepsin D mRNA. These results suggest that DC primarily employ cathepsin D (and perhaps E) to digest PPD into antigenic peptides.
Background: The neurophysiological and neuroanatomical foundations of persistent developmental stuttering (PDS) are still a matter of dispute. A main argument is that stutterers show atypical anatomical asymmetries of speech-relevant brain areas, which possibly affect speech fluency. The major aim of this study was to determine whether adults with PDS have anomalous anatomy in cortical speech-language areas. Methods: Adults with PDS (n = 10) and controls (n = 10) matched for age, sex, hand preference, and education were studied using high-resolution MRI scans. Using a new variant of the voxel-based morphometry technique (augmented VBM) the brains of stutterers and non-stutterers were compared with respect to white matter (WM) and grey matter (GM) differences. Results: We found increased WM volumes in a right-hemispheric network comprising the superior temporal gyrus (including the planum temporale), the inferior frontal gyrus (including the pars triangularis), the precentral gyrus in the vicinity of the face and mouth representation, and the anterior middle frontal gyrus. In addition, we detected a leftward WM asymmetry in the auditory cortex in non-stutterers, while stutterers showed symmetric WM volumes. Conclusions: These results provide strong evidence that adults with PDS have anomalous anatomy not only in perisylvian speech and language areas but also in prefrontal and sensorimotor areas. Whether this atypical asymmetry of WM is the cause or the consequence of stuttering is still an unanswered question. This article is available from: http://www.biomedcentral.com/1471-2377/4/23 © 2004 Jäncke et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
First paragraph (this article has no abstract) Persistent stimulation of nociceptors results in sensitization of nociceptive sensory neurons, which is associated with hyperalgesia and allodynia. The release of NO and subsequent synthesis of cGMP in the spinal cord are involved in this process. cGMP-dependent protein kinase I (PKG-I) has been suggested to act as a downstream target of cGMP, but its exact role in nociception hadn't been characterized yet. To further evaluate the NO/cGMP/PKG-I pathway in nociception we assessed the effects of PKG-I inhibiton and activaton in the rat formalin assay and analyzed the nociceptive behavior of PKG-I-/- mice. Open access article.
Background: Tumor development remains one of the major obstacles following organ transplantation. Immunosuppressive drugs such as cyclosporine and tacrolimus directly contribute to enhanced malignancy, whereas the influence of the novel compound mycophenolate mofetil (MMF) on tumor cell dissemination has not been explored. We therefore investigated the adhesion capacity of colon, pancreas, prostate and kidney carcinoma cell lines to endothelium, as well as their beta1 integrin expression profile before and after MMF treatment. Methods: Tumor cell adhesion to endothelial cell monolayers was evaluated in the presence of 0.1 and 1 μM MMF and compared to unstimulated controls. beta1 integrin analysis included alpha1beta1 (CD49a), alpha2beta1 (CD49b), alpha3beta1 (CD49c), alpha4beta1 (CD49d), alpha5beta1 (CD49e), and alpha6beta1 (CD49f) receptors, and was carried out by reverse transcriptase-polymerase chain reaction, confocal microscopy and flow cytometry. Results: Adhesion of the colon carcinoma cell line HT-29 was strongly reduced in the presence of 0.1 μM MMF. This effect was accompanied by down-regulation of alpha3beta1 and alpha6beta1 surface expression and of alpha3beta1 and alpha6beta1 coding mRNA. Adhesion of the prostate tumor cell line DU-145 was blocked dose-dependently by MMF. In contrast to MMF's effects on HT-29 cells, MMF dose-dependently up-regulated alpha1beta1, alpha2beta1, alpha3beta1, and alpha5beta1 on DU-145 tumor cell membranes. Conclusion: We conclude that MMF possesses distinct anti-tumoral properties, particularly in colon and prostate carcinoma cells. Adhesion blockage of HT-29 cells was due to the loss of alpha3beta1 and alpha6beta1 surface expression, which might contribute to a reduced invasive behaviour of this tumor entity. The enhancement of integrin beta1 subtypes observed in DU-145 cells possibly causes re-differentiation towards a low-invasive phenotype.
Introduction: This open label, multicentre study was conducted to assess the times to offset of the pharmacodynamic effects and the safety of remifentanil in patients with varying degrees of renal impairment requiring intensive care.
Methods: A total of 40 patients, who were aged 18 years or older and had normal/mildly impaired renal function (estimated creatinine clearance ≥ 50 ml/min; n = 10) or moderate/severe renal impairment (estimated creatinine clearance <50 ml/min; n = 30), were entered into the study. Remifentanil was infused for up to 72 hours (initial rate 6–9 μg/kg per hour), with propofol administered if required, to achieve a target Sedation–Agitation Scale score of 2–4, with no or mild pain.
Results: There was no evidence of increased offset time with increased duration of exposure to remifentanil in either group. The time to offset of the effects of remifentanil (at 8, 24, 48 and 72 hours during scheduled down-titrations of the infusion) were more variable and were statistically significantly longer in the moderate/severe group than in the normal/mild group at 24 hours and 72 hours. These observed differences were not clinically significant (the difference in mean offset at 72 hours was only 16.5 min). Propofol consumption was lower with the remifentanil based technique than with hypnotic based sedative techniques. There were no statistically significant differences between the renal function groups in the incidence of adverse events, and no deaths were attributable to remifentanil use.
Conclusion: Remifentanil was well tolerated, and the offset of pharmacodynamic effects was not prolonged either as a result of renal dysfunction or prolonged infusion up to 72 hours.
Western cultures have witnessed a tremendous cultural and social transformation of sexuality in the years since the sexual revolution. Apart from a few public debates and scandals, the process has moved along gradually and quietly. Yet its real and symbolic effects are probably much more consequential than those generated by the sexual revolution of the sixties. Sigusch refers to the broad-based recoding and reassessment of the sexual sphere during the eighties and nineties as the "neosexual revolution". The neosexual revolution is dismantling the old patterns of sexuality and reassembling them anew. In the process, dimensions, intimate relationships, preferences and sexual fragments emerge, many of which had submerged, were unnamed or simply did not exist before. In general, sexuality has lost much of its symbolic meaning as a cultural phenomenon. Sexuality is no longer the great metaphor for pleasure and happiness, nor is it so greatly overestimated as it was during the sexual revolution. It is now widely taken for granted, much like egotism or motility. Whereas sex was once mystified in a positive sense - as ecstasy and transgression, it has now taken on a negative mystification characterized by abuse, violence and deadly infection. While the old sexuality was based primarily upon sexual instinct, orgasm and the heterosexual couple, neosexualities revolve predominantly around gender difference, thrills, self-gratification and prosthetic substitution. From the vast number of interrelated processes from which neosexualities emerge, three empirically observable phenomena have been selected for discussion here: the dissociation of the sexual sphere, the dispersion of sexual fragments and the diversification of intimate relationships. The outcome of the neosexual revolution may be described as "lean sexuality" and "self-sex".
E-Learning soll im Rahmen der allgemeinmedizinischen Ausbildung von Medizinstudierenden erprobt werden. Ein zielgruppenspezifisches, multimodulares Online-Angebot begleitet Medizinstudenten des 10. Semesters während ihres dezentralen Praktikums in hausärztlichen Praxen. Folgende Lehrziele werden angestrebt: (1) Einführung in das E-Learning, (2) Klinische Allgemeinmedizin - Online-Modul, (3) Chronic Care Online-Modul, (4) Online-Bewerbung. Die systematische Evaluation zeigt, dass E-Learning die Kommunikation der Studierenden untereinander und mit der universitären Lehreinheit während des Praktikum fördert. Auf der Grundlage der in diesem Pilotversuch gewonnenen Erfahrungen erscheint die Kombination mit Präsenzunterricht (Blended Learning) eine vielversprechende Option für die allgemeinmedizinische Ausbildung zu sein.