96 resultados para Contractile phenotype
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Elevated serum ferritin levels may reflect a systemic inflammatory state as well as increased iron storage, both of which may contribute to an unfavorable outcome of chronic hepatitis C (CHC). We therefore performed a comprehensive analysis of the role of serum ferritin and its genetic determinants in the pathogenesis and treatment of CHC. To this end, serum ferritin levels at baseline of therapy with pegylated interferon-alpha and ribavirin or before biopsy were correlated with clinical and histological features of chronic hepatitis C virus (HCV) infection, including necroinflammatory activity (N = 970), fibrosis (N = 980), steatosis (N = 886), and response to treatment (N = 876). The association between high serum ferritin levels (> median) and the endpoints was assessed by logistic regression. Moreover, a candidate gene as well as a genome-wide association study of serum ferritin were performed. We found that serum ferritin ≥ the sex-specific median was one of the strongest pretreatment predictors of treatment failure (univariate P < 0.0001, odds ratio [OR] = 0.45, 95% confidence interval [CI] = 0.34-0.60). This association remained highly significant in a multivariate analysis (P = 0.0002, OR = 0.35, 95% CI = 0.20-0.61), with an OR comparable to that of interleukin (IL)28B genotype. When patients with the unfavorable IL28B genotypes were stratified according to high versus low ferritin levels, SVR rates differed by > 30% in both HCV genotype 1- and genotype 3-infected patients (P < 0.001). Serum ferritin levels were also independently associated with severe liver fibrosis (P < 0.0001, OR = 2.67, 95% CI = 1.68-4.25) and steatosis (P = 0.002, OR = 2.29, 95% CI = 1.35-3.91), but not with necroinflammatory activity (P = 0.3). Genetic variations had only a limited impact on serum ferritin levels. Conclusion: In patients with CHC, elevated serum ferritin levels are independently associated with advanced liver fibrosis, hepatic steatosis, and poor response to interferon-alpha-based therapy.
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Introduction: The Alternative Lengthening of Telomeres (ALT) mechanism is a significant prognostic factor for longer survival in patients with GBM, irrespective of age. The reasons for this are unknown. We considered two possibilities; firstly that ALT identifies a subset of less aggressive GBMs, or alternatively, a group of tumours that respond more favourably to adjuvant therapy. Methods: ALT was determined by staining for ALT Associated PML Bodies (APBs) in archival tissue in a retrospective analysis of 573 GBM patients. IDH1 mutation was determined by immunohistochemistry in a subset of these. Results: We identified the presence of the telomerase-independent ALT in 15% of GBM patients and found that it correlated with survival (22% of ALT patients survive more than 2 years compared to 9% for non-ALT). This survival advantage was independent of surgery type (biopsy or full resection) and treatment (radiotherapy and chemotherapy). Interestingly ALT conferred a significant survival advantage for patients who only received surgery (13.3 months compared to 5.5 months) (19% vs 1% .2 year survival). This survival benefit was also observed in GBM patients who received surgery and radiotherapy (18.5% vs 2.4%. 2 year survival), but less so for chemotherapy (21% vs 17% . 2 year survival). For the ALT patients the fraction surviving more than 2 years did not improve significantly with adjuvant therapy. IDH1 mutation also associated with ALT. Conclusions: These data indicate ALT+ tumours are biologically distinct and associated with improved patient survival, probably due to less aggressive/invasive growth. However they respond poorly to current adjuvant treatment and therefore new therapies are urgently needed for this group.
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We investigate the coevolution between philopatry and altruism in island-model populations when kin recognition occurs through phenotype matching. In saturated environments, a good discrimination ability is a necessary prerequisite for the emergence of sociality. Discrimination decreases not only with the average phenotypic similarity between immigrants and residents (i.e., with environmental homogeneity and past gene flow) but also with the sampling variance of similarity distributions (a negative function of the number of traits sampled). Whether discrimination should rely on genetically or environmentally determined traits depends on the apportionment of phenotypic variance and, in particular, on the relative values of e (the among-group component of environmental variance) and r (the among-group component of genetic variance, which also measures relatedness among group members). If r exceeds e, highly heritable cues do better. Discrimination and altruism, however, remain low unless philopatry is enforced by ecological constraints. If e exceeds r, by contrast, nonheritable traits do better. High e values improve discrimination drastically and thus have the potential to drive sociality, even in the absence of ecological constraints. The emergence of sociality thus can be facilitated by enhancing e, which we argue is the main purpose of cue standardization within groups, as observed in many social insects, birds, and mammals, including humans.
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Mutations in LACERATA (LCR), FIDDLEHEAD (FDH), and BODYGUARD (BDG) cause a complex developmental syndrome that is consistent with an important role for these Arabidopsis genes in cuticle biogenesis. The genesis of their pleiotropic phenotypes is, however, poorly understood. We provide evidence that neither distorted depositions of cutin, nor deficiencies in the chemical composition of cuticular lipids, account for these features, instead suggesting that the mutants alleviate the functional disorder of the cuticle by reinforcing their defenses. To better understand how plants adapt to these mutations, we performed a genome-wide gene expression analysis. We found that apparent compensatory transcriptional responses in these mutants involve the induction of wax, cutin, cell wall, and defense genes. To gain greater insight into the mechanism by which cuticular mutations trigger this response in the plants, we performed an overlap meta-analysis, which is termed MASTA (MicroArray overlap Search Tool and Analysis), of differentially expressed genes. This suggested that different cell integrity pathways are recruited in cesA cellulose synthase and cuticular mutants. Using MASTA for an in silico suppressor/enhancer screen, we identified SERRATE (SE), which encodes a protein of RNA-processing multi-protein complexes, as a likely enhancer. In confirmation of this notion, the se lcr and se bdg double mutants eradicate severe leaf deformations as well as the organ fusions that are typical of lcr and bdg and other cuticular mutants. Also, lcr does not confer resistance to Botrytis cinerea in a se mutant background. We propose that there is a role for SERRATE-mediated RNA signaling in the cuticle integrity pathway.
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Objectives: Existing VADs are single-ventricle pumps needing anticoagulation. We developed a bi-ventricular external assist device that partially reproduces the physiological muscle function of the heart. This artificial muscle could wrap the heart and improve its contractile force.Methods: The device has a carbon fiber skeleton fitting a 30-40kg patient's heart, to which a Nitinol based artificial muscle is connected. The artificial muscle wraps both ventricles. The Nitinol fibers are woven on a Kevlar mesh surrounding each ventricle. The fibers are electrically driven with a dedicated control unit developed for this purpose. We assessed hemodynamic performances of this device using a previously described dedicated bench test. Volume ejected and pressure gradient have been measured with afterload ranging from 10 to 50mmHg.Results: With an afterload of 50mmHg the system has an ejection fraction of 4% on the right side and 5% on the left side. The system is able to generate a systolic ejection of 2.2mL on the right side and 3.25mL on the left side. With an afterload of 25mmHg the results are reduced of about 20%. The activation frequency can reach 80/minute resulting in a total volume displacement of 176mL/minute on the right side and 260mL/minute on the left side.Conclusions: These preliminary studies confirmed the possibility of improving the ejection fraction of a failing heart using artificial muscle for external cardiac compression avoiding anticoagulation therapy. This device could be helpful in weaning cardio-pulmonary bypass and/or for short-term cardio-circulatory support in pediatric population with cardiac failure.
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We report the case of a 37-year-old man suffering from insidious visual agnosia and spastic paraparesis due to a PSEN1 mutation. His mother was diagnosed with Alzheimer disease after a biopsy. He was assessed by multimodal neuroimaging, including new in vivo positron emission tomography amyloid imaging (F-AV45). His data were compared with those from healthy participants and patients with sporadic predemential Alzheimer disease. He exhibited posterior cortical thickness reduction, posterior hypometabolism, and increased amyloid ligand uptake in the posterior cortex and the striatum. We show that F-AV45 positron emission tomography allows visualization of the unusual pattern of amyloid deposits that co-localize with cortical atrophy in this genetic form of Alzheimer disease.
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The expression of the serum- and glucocorticoid-regulated kinase 1 (Sgk1) is induced by mineralocorticoids and, in turn, upregulates the renal epithelial Na(+) channel (ENaC). Total inactivation of Sgk1 has been associated with transient urinary Na(+) wasting with a low-Na(+) diet, while the aldosterone-mediated ENaC channel activation was unchanged in the collecting duct. Since Sgk1 is ubiquitously expressed, we aimed to study the role of renal Sgk1 and generated an inducible kidney-specific knockout (KO) mouse. We took advantage of the previously described TetOn/CreLoxP system, in which rtTA is under the control of the Pax8 promotor, allowing inducible inactivation of the floxed Sgk1 allele in the renal tubules (Sgk1fl/fl/Pax8/LC1 mice). We found that under a standard Na(+) diet, renal water and Na(+)/K(+) excretion had a tendency to be higher in doxycycline-treated Sgk1 KO mice compared with control mice. The impaired ability of Sgk1 KO mice to retain Na(+) increased significantly with a low-salt diet despite higher plasma aldosterone levels. On a low-Na(+) diet, the Sgk1 KO mice were also hyperkaliuric and lost body weight. This phenotype was accompanied by a decrease in systolic and diastolic blood pressure. At the protein level, we observed a reduction in phosphorylation of the ubiquitin protein-ligase Nedd4-2 and a decrease in the expression of the Na(+)-Cl(-)-cotransporter (NCC) and to a lesser extent of ENaC.
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PURPOSE OF REVIEW: Definition of T cell immune correlates in HIV infection remains a lofty goal towards our understanding of the HIV-specific immune response. This review will focus upon recent developments and controversies in our understanding of protective T cell responses against HIV. RECENT FINDINGS: It has become clear that multiple functions and phenotypic markers of T cells must be assessed to accurately characterize the complexity of CD4 and CD8 T cell responses. While evidence indicates that a hallmark of protective immune responses in HIV infection is the presence of 'polyfunctional' T cell responses, a disconnect remains between the function and phenotype of effective HIV-specific T cells. Moreover, there may be inherent differences in the ability of specific human leukocyte antigen class I families to promote CD8 T cell effector versus polyfunctional responses. It remains to be determined how polyfunctional responses arise in HIV infection, which functions are important for control, and whether surface phenotype markers provide an indication of protective capacity. SUMMARY: Polyfunctional and phenotypic assessment of T cell responses have clearly advanced our understanding of HIV specific immune responses. Critical questions remain, however, especially whether polyfunctional T cell responses control, or are controlled by, HIV replication.
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PURPOSE: To describe the clinical, spectral-domain optical coherence tomography and electrophysiological features of C1QTNF5-associated late-onset retinal degeneration in a molecularly confirmed pedigree. METHODS: Five members of a family participated, and affected individuals (n = 4) underwent detailed ophthalmologic evaluation including fundus autofluorescence and spectral-domain optical coherence tomography imaging and electroretinography. Electrooculography was performed in three individuals. RESULTS: The visual acuity was initially normal and worsened with time. Anterior segment abnormalities included peripupillary iris atrophy and long anterior insertion of zonules. Peripapillary atrophy, drusenoid deposition, and scalloped sectorial chorioretinal atrophy were observed in all older individuals (n = 3). Fundus autofluorescence demonstrated hypofluorescent areas corresponding to regions of chorioretinal atrophy. The spectral-domain optical coherence tomography demonstrated multiple areas of retinal pigment epithelium-Bruch membrane separation with intervening homogeneous deposition that corresponded to the drusenoid lesions and areas of chorioretinal atrophy. Electrooculography was normal in one individual and showed abnormally low dark trough measures in older individuals (n = 2). Electroretinography was normal in early stages (n = 1), but showed marked abnormalities in the rod system (n = 3), which was predominantly inner retinal (n = 2) in late stages. CONCLUSION: Late-onset retinal degeneration is a progressive degeneration, and anterior segment abnormalities present early. The widespread sub-retinal pigment epithelium deposition seen on spectral-domain optical coherence tomography in older individuals appears to be a characteristic in late stages. Electrooculography demonstrates abnormalities only in late stages of the disease.
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Purpose: The M-band is an important cytoskeletal structure in the centre of the sarcomere, believed to cross-link the thick filament lattice. Its main components are three closely related modular proteins from the myomesin gene family: Myomesin, M-protein and myomesin-3. Each muscle is characterized by its unique M-band protein composition, depending on the contractile parameters of a particular fiber. To investigate the role of the M-band in one of the most relevant and clinically increasing cardiac diseases, we analyzed the expression of myomesin proteins in dilated cardiomyopathy (DCM).Methods: In a previous study we analyzed mouse models suffering from DCM, demonstrating that the embryonic heart specific EH-myomesin splicing isoform was up-regulated directly corresponding to the degree of cardiac dysfunction and ventricular dilation. Based on this study, human ventricular and atrial samples (n=32) were obtained during heart surgery after informed consent and approval by an institutional review board. Patients were aged 30-70 years and suffered from dilated cardiomyopathy (DCM;n=13), Hypertrophic Cardiomyopathy (HCM;n=10) or served as controls (n=9). Patients suffering from DCM or HCM were in endstage heart-failure (NYHA III-IV) and either underwent heart transplantation or Left Ventricular Assist Device (LVAD) implantation. Heart samples from patients who underwent valve surgery or congenital heart surgery served as controls. Heart Samples were analyzed using RT-PCR, Western blot, and immunofluorescence.Results: By investigating the expression pattern of myomesins, we found that DCM is accompanied by specific M-band alterations, which were more pronounced in ventricular samples compared to the atrium. Changes in the amounts of different myomesins during DCM occurred in a cell-specific manner, leading to a higher heterogeneity of the cytoskeleton in cardiomyocytes through the myocardial wall with some cells switching completely to an embryonic phenotype.Conclusions: Here we present that the embryonic heart specific EH-myomesin isoform is up-regulated in human DCM. The alterations of the M-band protein composition might be part of a general adaptation of the sarcomeric cytoskeleton to unfavorable working conditions in the failing heart and may modify the mechanical properties of the cardiomyocytes. We suggest that the upregulation of EH-myomesin might play a pivotal role in DCM and might support classical imagingas a novel sarcomeric marker for this disease.
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Introduction: Recently, mesenchymal stem cells (MSC) of perivascular origin have been identified in several organs not including the heart. Using a novel cell isolation protocol, we have isolated cells sharing common characteristics from mouse hearts and pancreas. The aim of the present study was to characterize these cells in vitro.Methods: Cells were isolated from neonatal and adult mouse hearts and pancreas and cultured for more than 6 months. Surface marker expression was analyzed by flow cytometry and immunocytochemistry. Cell differentiation was tested using multiple differentiation media. Insulin production by pancreas-derived cells was tested by dithizone staining.Results: Cells showing a similar, distinctive morphology were obtained from the heart and pancreas after 4-8 weeks of culture. Cells from the two organs also showed a very similar immunophenotype, characterized by expression of c-kit (stem cell factor receptor), CD44, the common leukocyte marker CD45, and the monocytic markers CD11b and CD14. A significant proportion of cardiac and pancreatic cells expressed NG2, a marker for pericytes and other vascular cells. A significant proportion of cardiac, but not of pancreatic cells expressed stem cell antigen-1 (Sca-1). However, cells did not express T, B or dendritic cell markers. Cells of both cardiac and pancreatic origin spontaneously formed "spheres" (spherical cell aggregates similar to "neurospheres" formed by neural stem cells) in vitro. Cardiosphere formation was enhanced by TNF-alpha. Several cardiospheres (but no "pancreatospheres") derived from neonatal (but not adult) cells showed spontaneous rhythmic contractions, thus demonstrating cardiac differentiation (this was confirmed by immunostaining for alpha-sarcomeric actinin). Beating activity was enhanced by low serum conditions. Cells from both organs formed adipocytes, osteocytes and osteocytes under appropriate conditions, the typical differentiation pattern of MSCs. Pancreas-derived cells also formed dithizonepositive insulin-producing cells.Conclusions: We have defined cardiac and pancreatic cell populations that share a common morphology, growth characteristics, and a unique immunophenotype. Expression of perivascular and monocytic markers, along with stem/priogenitor cell markers by these cells suggests a relationship with pericytes-mesoangioblasts and so-called multipotent monocytes. Cells show MSC-typical growth and differentiation patterns, together with tissue-specific differentiation potential: cardiomyocytes for cardiac-derived cells and insulinproducing cells for pancreas-derived cells.