958 resultados para 1096
Resumo:
OBJECTIVE: A multidimensional lifestyle intervention performed in 652 preschoolers (72% of migrant, 38% of low educational level (EL) parents) reduced body fat, but not BMI and improved fitness. The objective of this study is to examine whether the intervention was equally effective in children of migrant and/or low EL parents.¦METHODS: Cluster-randomized controlled single blinded trial, conducted in 2008/09 in 40 randomly selected preschools in Switzerland. The culturally tailored intervention consisted of a physical activity program and lessons on nutrition, media use and sleep. Primary outcomes included BMI and aerobic fitness. Secondary outcomes included %body fat, waist circumference and motor agility.¦RESULTS: Children of migrant parents benefitted similarly from the intervention compared to their counterparts (p for interaction≥ 0.09). However, children of low EL parents benefitted less, although these differences did not reach statistical significance (p for interaction≥ 0.06). Average intervention effect sizes for BMI were -0.10, -0.05, -0.11 and 0.04 kg/m(2) and for aerobic fitness were 0.55, 0.20, 0.37 and -0.05 stages for children of non-migrant, migrant, middle/high EL and low EL parents, respectively.¦CONCLUSIONS: This intervention was similarly effective among preschoolers of migrant parents compared to their counterparts, while children of low EL parents benefitted less.
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A crucial step in the arenavirus life cycle is the proteolytic processing of the viral envelope glycoprotein precursor (GPC) by the cellular proprotein convertase (PC) subtilisin kexin isozyme-1 (SKI-1)/site-1 protease (S1P). Here we conducted a systematic and quantitative analysis of SKI-1/S1P processing of peptides derived from the recognition sites of GPCs of different Old World and New World arenaviruses. We found that SKI-1/S1P showed a strong preference for arenaviral sequences resembling its autoprocessing sites, which are recurrent motifs in arenaviral GPCs. The African arenaviruses Lassa, Mobala, and Mopeia resemble the SKI-1/S1P autoprocessing C-site, whereas sequences derived from Clade B New World viruses Junin and Tacaribe have similarities to the autoprocessing B-site. In contrast, analogous peptides derived from cellular SKI-1/S1P substrates were remarkably poor substrates. The data suggest that arenavirus GPCs evolved to mimic SKI-1/S1P autoprocessing sites, likely ensuring efficient cleavage and perhaps avoiding competition with SKI-1/S1P's cellular substrates.
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Ten years ago, the first cellular receptor for the prototypic arenavirus lymphocytic choriomeningitis virus (LCMV) and the highly pathogenic Lassa virus (LASV) was identified as alpha-dystroglycan (alpha-DG), a versatile receptor for proteins of the extracellular matrix (ECM). Biochemical analysis of the interaction of alpha-DG with arenaviruses and ECM proteins revealed a strikingly similar mechanism of receptor recognition that critically depends on specific sugar modification on alpha-DG involving a novel class of putative glycosyltransferase, the LARGE proteins. Interestingly, recent genome-wide detection and characterization of positive selection in human populations revealed evidence for positive selection of a locus within the LARGE gene in populations from Western Africa, where LASV is endemic. While most enveloped viruses that enter the host cell in a pH-dependent manner use clathrin-mediated endocytosis, recent studies revealed that the Old World arenaviruses LCMV and LASV enter the host cell predominantly via a novel and unusual endocytotic pathway independent of clathrin, caveolin, dynamin, and actin. Upon internalization, the virus is rapidly delivered to endosomes via an unusual route of vesicular trafficking that is largely independent of the small GTPases Rab5 and Rab7. Since infection of cells with LCMV and LASV depends on DG, this unusual endocytotic pathway could be related to normal cellular trafficking of the DG complex. Alternatively, engagement of arenavirus particles may target DG for an endocytotic pathway not normally used in uninfected cells thereby inducing an entry route specifically tailored to the pathogen's needs.
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Decapentaplegic (Dpp), the fly homolog of the secreted mammalian BMP2/4 signaling molecules, is involved in almost all aspects of fly development. Dpp has critical functions at all developmental stages, from patterning of the eggshell to the determination of adult intestinal stem cell identity. Here, we focus on recent findings regarding the transcriptional regulatory logic of the pathway, on a new feedback regulator, Pentagone, and on Dpp's roles in scaling and growth of the Drosophila wing.
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Background And Objectives: Isolated limb perfusion with TNF-alpha and melphalan (TM-ILP) is a limb salvage therapy for non-resectable soft tissue sarcomas (STS) of the extremities. It is indicated for patients for whom amputation or debilitating surgery is the only alternative. It can be used either as an exclusive therapy (in palliation) or as a neo-adjuvant treatment, followed by marginal resection of tumor remnants with minimal functional impairment. Methods: Between February 1992 and March 2006, 57 TM-ILPs were performed on 51 patients with 88% high grade and 84% advanced stage tumors. Results: Mean follow-up is 38.9 months (4-159, median 22 months). Twenty-one percent patients had significant early complications, with 3 major re-operations, and 23% suffered long-lasting complications. Complete response was observed in 25%, partial response in 42%, stable disease in 14% and progressive disease in 14%. Resection of the tumor remnants was possible in 65%. A complementary treatment was necessary in 31%, mostly radiation therapy. A local recurrence was observed in 35%, after a mean of 20.3 months (2-78), and distant relapse was seen in 45%, after a mean of 13.4 months (5-196). Mean Disease-free survival was 14.9 months, and overall 5-year-survival 43.5%. Amputation rate at 5 years was 24%. Conclusions: TM-ILP is a conservative treatment with a high complications rate, but it can be successful even for the most severe STS of extremities. As a consequence the limb can be spared from amputation or debilitating surgery on the long term in about 75% of patients
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Inflammatory bowel diseases are a result of an aberrant mucosal immune response to gut microflora. Several groups have reported newly diagnosed inflammatory bowel diseases following solid organ transplantation and subsequent immunosuppressive therapy. We describe four cases of newly diagnosed inflammatory bowel diseases following liver transplantation in a pool of 120 transplanted patients. These patients had no prior history of inflammatory bowel diseases or primary sclerosing cholangitis and were immunosuppressed. Two patients were transplanted for a hepatitis C related cirrhosis, one for alcoholic cirrhosis and one patient for autoimmune cirrhosis. Three patients were diagnosed with ulcerative colitis and one with Crohn's disease. These four patients were on a cyclosporin monotherapy when their inflammatory bowel diseases were diagnosed. These data suggest that cyclosporin monotherapy following solid organ transplantation does not prevent development of inflammatory bowel diseases.
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The epithelial sodium channel (ENaC) is responsible for Na+ and fluid absorption across colon, kidney, and airway epithelia. We have previously identified SPLUNC1 as an autocrine inhibitor of ENaC. We have now located the ENaC inhibitory domain of SPLUNC1 to SPLUNC1's N terminus, and a peptide corresponding to this domain, G22-A39, inhibited ENaC activity to a similar degree as full-length SPLUNC1 (∼2.5 fold). However, G22-A39 had no effect on the structurally related acid-sensing ion channels, indicating specificity for ENaC. G22-A39 preferentially bound to the β-ENaC subunit in a glycosylation-dependent manner. ENaC hyperactivity is contributory to cystic fibrosis (CF) lung disease. Addition of G22-A39 to CF human bronchial epithelial cultures (HBECs) resulted in an increase in airway surface liquid height from 4.2±0.6 to 7.9±0.6 μm, comparable to heights seen in normal HBECs, even in the presence of neutrophil elastase. Our data also indicate that the ENaC inhibitory domain of SPLUNC1 may be cleaved away from the main molecule by neutrophil elastase, which suggests that it may still be active during inflammation or neutrophilia. Furthermore, the robust inhibition of ENaC by the G22-A39 peptide suggests that this peptide may be suitable for treating CF lung disease.
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Telomerase activity has been detected in germ cells as well as in the developing embryo. Activity is no longer detectable in most somatic cells of the neonate, although low levels of activity persist in regenerative tissues. Telomerase has been found to be reactivated or up-regulated in the majority of cancers. The colorectal adenoma-carcinoma sequence is one of the best-characterized models of multistep tumourigenesis and is thus suitable for determining at which stage telomerase is activated. Telomerase activity was examined by telomeric repeat amplification protocol (TRAP) assay in 96 cases of colorectal tissues, including 50 carcinomas, 31 adenomas, and 15 normal colonic tissues. For each case, histological diagnosis and telomerase activity were determined on consecutive frozen sections. In order to reduce the chance of a false-negative TRAP assay due to RNA degradation, the integrity of rRNA in the tissues was verified in each case. Twenty-five carcinomas, 30 adenomas, and all of the 15 normal colorectal mucosal samples showed no or only partial rRNA degradation and only in these cases was the TRAP assay interpreted. None of the normal tissues exhibited telomerase activity. In contrast, all of the 25 cancers and 47 per cent (14/30) of the adenomas were positive. In adenomas, telomerase activation was highly significantly related to the grade of dysplasia (p< 0.0001). All adenomas which contained high-grade dysplasia revealed telomerase activity, whereas telomerase activity was detectable in only 20 per cent (4/20) of cases with exclusively low-grade dysplasia. These results indicate that telomerase activation, which may be an obligatory step in colorectal carcinogenesis, occurs in the progression from low-grade to high-grade dysplasia in adenomas. Furthermore, in the adenoma-carcinoma sequence, telomerase activation seems to occur later than K- ras mutation but earlier than p53 mutation.
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Due to its small size and particular isolating barriers, the eye is an ideal target for local therapy. Recombinant protein ocular delivery requires invasive and painful repeated injections. Alternatively, a transfected tissue might be used as a local producer of transgene-encoded therapeutic protein. We have developed a nondamaging electrically mediated plasmid delivery technique (electrotransfer) targeted to the ciliary muscle, which is used as a reservoir tissue for the long-lasting expression and secretion of therapeutic proteins. High and long-lasting reporter gene expression was observed, which was restricted to the ciliary muscle. Chimeric TNF-alpha soluble receptor (hTNFR-Is) electrotransfer led to elevated protein secretion in aqueous humor and to drastic inhibition of clinical and histological inflammation scores in rats with endotoxin-induced uveitis. No hTNFR-Is was detected in the serum, demonstrating the local delivery of proteins using this method. Plasmid electrotransfer to the ciliary muscle, as performed in this study, did not induce any ocular pathology or structural damage. Local and sustained therapeutic protein production through ciliary muscle electrotransfer is a promising alternative to repeated intraocular protein administration for a large number of inflammatory, degenerative, or angiogenic diseases.
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EGFR receptor is expressed on most of the non small cell lung carcinoma (NSCLC) cells. Its relative importance in oncogenesis and tumour progression seems to greatly vary among NSCLC. Two molecules targeting differently EGFR are currently used for the treatment of metastatic NSCLC. cetuximab, a monoclonal antibody directed against the extracellular domain of the receptor, leads to a moderate survival benefit when associated with standard first-line chemotherapy. Erlotinib, a small EGFR tyrosine-kinase inhibitor molecule is used in 2nd or 3rd treatment line. Predictive factors for efficiency of these new treatments are subjects of intense research, in order to allow a better selection of the patients who could benefit from such a strategy.
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The ability to efficiently produce recombinant proteins in a secreted form is highly desirable and cultured mammalian cells such as CHO cells have become the preferred host as they secrete proteins with human-like post-translational modifications. However, attempts to express high levels of particular proteins in CHO cells may consistently result in low yields, even for non-engineered proteins such as immunoglobulins. In this study, we identified the responsible faulty step at the stage of translational arrest, translocation and early processing for such a "difficult-to-express" immunoglobulin, resulting in improper cleavage of the light chain and its precipitation in an insoluble cellular fraction unable to contribute to immunoglobulin assembly. We further show that proper processing and secretion were restored by over-expressing human signal receptor protein SRP14 and other components of the secretion pathway. This allowed the expression of the difficult-to-express protein to high yields, and it also increased the production of an easy-to-express protein. Our results demonstrate that components of the secretory and processing pathways can be limiting, and that engineering of the secretory pathway may be used to improve the secretion efficiency of therapeutic proteins from CHO cells.
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Because of the large variability in the pharmacokinetics of anti-HIV drugs, therapeutic drug monitoring in patients may contribute to optimize the overall efficacy and safety of antiretroviral therapy. An LC-MS/MS method for the simultaneous assay in plasma of the novel antiretroviral agents rilpivirine (RPV) and elvitegravir (EVG) has been developed to that endeavor. Plasma samples (100 μL) extraction is performed by protein precipitation with acetonitrile, and the supernatant is subsequently diluted 1:1 with 20-mM ammonium acetate/MeOH 50:50. After reverse-phase chromatography, quantification of RPV and EVG, using matrix-matched calibration samples, is performed by electrospray ionization-triple quadrupole mass spectrometry by selected reaction monitoring detection using the positive mode. The stable isotopic-labeled compounds RPV-(13) C6 and EVG-D6 were used as internal standards. The method was validated according to FDA recommendations, including assessment of extraction yield, matrix effects variability (<6.4%), as well as EVG and RPV short and long-term stability in plasma. Calibration curves were validated over the clinically relevant concentrations ranging from 5 to 2500 ng/ml for RPV and from 50 to 5000 ng/ml for EVG. The method is precise (inter-day CV%: 3-6.3%) and accurate (3.8-7.2%). Plasma samples were found to be stable (<15%) in all considered conditions (RT/48 h, +4°C/48 h, -20°C/3 months and 60°C/1 h). Selected metabolite profiles analysis in patients' samples revealed the presence of EVG glucuronide, that was well separated from parent EVG, allowing to exclude potential interferences through the in-source dissociation of glucuronide to parent drug. This new, rapid and robust LCMS/MS assay for the simultaneous quantification of plasma concentrations of these two major new anti-HIV drugs EVG and RPV offers an efficient analytical tool for clinical pharmacokinetics studies and routine therapeutic drug monitoring service. Copyright © 2013 John Wiley & Sons, Ltd.
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BACKGROUND and OBJECTIVE: A non-touch laser-induced microdrilling procedure is studied on mouse zona pellucida (ZP). STUDY DESIGN/MATERIALS and METHODS: A 1.48-microns diode laser beam is focused in a 8-microns spot through a 45x objective of an inverted microscope. Mouse zygotes, suspended in a culture medium, are microdrilled by exposing their ZP to a short laser irradiation and allowed to develop in vitro. RESULTS: Various sharp-edged holes can be generated in the ZP with a single laser irradiation. Sizes can be varied by changing irradiation time (3-100 ms) or laser power (22-55 mW). Drilled zygotes present no signs of thermal damage under light and scanning electron microscopy and develop as expected in vitro, except for a distinct eight-shaped hatching behavior. CONCLUSION: The microdrilling procedure can generate standardized holes in mouse ZP, without any visible side effects. The hole formation can be explained by a local photothermolysis of the protein matrix.
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Approximately 520 Wilson disease-causing mutations in the ATP7B gene have been described to date. In this study we report DNA and RNA analyses carried out for molecular characterization of a consensus sequence splicing mutation found in homozygosity in a Swiss Wilson disease patient. RNA analysis of 1946 +6 T→C in both the peripheral lymphoblasts and liver resulted in the production in the propositus of only an alternative transcript lacking exons 6, 7, and 8 resulting most likely in alterations of cell biochemistry and disease. The patient presents an early form of severe hepatic disease characterized by hepatosplenomegaly, reduced hepatic function, anemia and thrombocytopenia indicating that 1946 +6 T→C is a severe mutation. Since identical results were obtained from both peripheral lymphoblasts and liver they also suggest that RNA studies of illegitimate transcripts can be safely used for molecular characterization of ATP7B splicing mutations, thus improving genetic counseling and diagnosis of Wilson disease. Moreover these studies, contribute to reveal the exact molecular mechanisms producing Wilson disease.
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Partitioning of proteins in cholesterol and sphingolipid enriched plasma membrane microdomains, called lipid rafts, is critical for many signal transduction and protein sorting events. Although raft partitioning of many signaling molecules remains to be determined, glycosylphosphatidyl-inositol (GPI)-anchored proteins possess high affinity for lipid rafts and are currently exploited as markers to investigate fundamental mechanisms in protein sorting and signal transduction events. In this study, we demonstrate that two recombinant GPI-anchored green fluorescent proteins (GFP-GPIs) that differ in their GPI signal sequence confer distinct localization in plasma membrane microdomains. GFP fused to the GPI signal of the decay accelerating factor GFP-GPI(DAF) partitioned exclusively in lipid rafts, whereas GFP fused to the GPI signal of TRAIL-R3, GFP-GPI(TRAIL-R3), associated only minimally with microdomains. In addition, we investigated the unique ability of purified GFP-GPIs to insert into membrane microdomains of primary lymphocytes. This cell surface painting allows rapid, stable, and functional association of the GPI-anchored proteins with the target cell plasma membrane. The distinct membrane localization of the two GFP-GPIs was observed irrespective of whether the GPI-anchored molecules were painted or transfected. Furthermore, we show that painted GFP-GPI(DAF) was totally dependent on the GPI anchor and that the membrane insertion was increased by the addition of raft-associated lipids such as cholesterol, sphingomyelin, and dipalmitoyl-phosphatidylethanolamine. Thus, this study provides evidence that different GPI signal sequences lead to distinct membrane microdomain localization and that painted GFP-GPI(DAF) serves as an excellent fluorescent marker for lipid rafts in live cells.