949 resultados para overrun causes


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The E3 ubiquitin ligase NEDD4-2 (encoded by the Nedd4L gene) regulates the amiloride-sensitive epithelial Na+ channel (ENaC/SCNN1) to mediate Na+ homeostasis. Mutations in the human β/γENaC subunits that block NEDD4-2 binding or constitutive ablation of exons 6-8 of Nedd4L in mice both result in salt-sensitive hypertension and elevated ENaC activity (Liddle syndrome). To determine the role of renal tubular NEDD4-2 in adult mice, we generated tetracycline-inducible, nephron-specific Nedd4L KO mice. Under standard and high-Na+ diets, conditional KO mice displayed decreased plasma aldosterone but normal Na+/K+ balance. Under a high-Na+ diet, KO mice exhibited hypercalciuria and increased blood pressure, which were reversed by thiazide treatment. Protein expression of βENaC, γENaC, the renal outer medullary K+ channel (ROMK), and total and phosphorylated thiazide-sensitive Na+Cl- cotransporter (NCC) levels were increased in KO kidneys. Unexpectedly, Scnn1a mRNA, which encodes the αENaC subunit, was reduced and proteolytic cleavage of αENaC decreased. Taken together, these results demonstrate that loss of NEDD4-2 in adult renal tubules causes a new form of mild, salt-sensitive hypertension without hyperkalemia that is characterized by upregulation of NCC, elevation of β/γENaC, but not αENaC, and a normal Na+/K+ balance maintained by downregulation of ENaC activity and upregulation of ROMK.

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The protease activity of the paracaspase Malt1 has recently gained interest as a drug target for immunomodulation and the treatment of diffuse large B-cell lymphomas. To address the consequences of Malt1 protease inactivation on the immune response in vivo, we generated knock-in mice expressing a catalytically inactive C472A mutant of Malt1 that conserves its scaffold function. Like Malt1-deficient mice, knock-in mice had strong defects in the activation of lymphocytes, NK and dendritic cells, and the development of B1 and marginal zone B cells and were completely protected against the induction of autoimmune encephalomyelitis. Malt1 inactivation also protected the mice from experimental induction of colitis. However, Malt1 knock-in mice but not Malt1-deficient mice spontaneously developed signs of autoimmune gastritis that correlated with an absence of Treg cells, an accumulation of T cells with an activated phenotype and high serum levels of IgE and IgG1. Thus, removal of the enzymatic activity of Malt1 efficiently dampens the immune response, but favors autoimmunity through impaired Treg development, which could be relevant for therapeutic Malt1-targeting strategies.

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BACKGROUND: Mutations in the sulfate transporter gene SLC26A2 (DTDST) cause a continuum of skeletal dysplasia phenotypes that includes achondrogenesis type 1B (ACG1B), atelosteogenesis type 2 (AO2), diastrophic dysplasia (DTD), and recessive multiple epiphyseal dysplasia (rMED). In 1972, de la Chapelle et al reported two siblings with a lethal skeletal dysplasia, which was denoted "neonatal osseous dysplasia" and "de la Chapelle dysplasia" (DLCD). It was suggested that DLCD might be part of the SLC26A2 spectrum of phenotypes, both because of the Finnish origin of the original family and of radiographic similarities to ACG1B and AO2. OBJECTIVE: To test the hypothesis whether SLC26A2 mutations are responsible for DLCD. METHODS: We studied the DNA from the original DLCD family and from seven Finnish DTD patients in whom we had identified only one copy of IVS1+2T>C, the common Finnish mutation. A novel SLC26A2 mutation was found in all subjects, inserted by site-directed mutagenesis in a vector harbouring the SLC26A2 cDNA, and expressed in sulfate transport deficient Chinese hamster ovary (CHO) cells to measure sulfate uptake activity. RESULTS: We identified a hitherto undescribed SLC26A2 mutation, T512K, homozygous in the affected subjects and heterozygous in both parents and in the unaffected sister. T512K was then identified as second pathogenic allele in the seven Finnish DTD subjects. Expression studies confirmed pathogenicity. CONCLUSIONS: DLCD is indeed allelic to the other SLC26A2 disorders. T512K is a second rare "Finnish" mutation that results in DLCD at homozygosity and in DTD when compounded with the milder, common Finnish mutation.

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BACKGROUND: Alcohol use causes high burden of disease and injury globally. Switzerland has a high consumption of alcohol, almost twice the global average. Alcohol-attributable deaths and years of life lost in Switzerland were estimated by age and sex for the year 2011. Additionally, the impact of heavy drinking (40+grams/day for women and 60+g/day for men) was estimated. METHODS: Alcohol consumption estimates were based on the Addiction Monitoring in Switzerland study and were adjusted to per capita consumption based on sales data. Mortality data were taken from the Swiss mortality register. Methodology of the Comparative Risk Assessment for alcohol was used to estimate alcohol-attributable fractions. RESULTS: Alcohol use caused 1,600 (95% CI: 1,472 - 1,728) net deaths (1,768 deaths caused, 168 deaths prevented) among 15 to 74 year olds, corresponding to 8.7% of all deaths (men: 1,181 deaths; women: 419 deaths). Overall, 42,627 years of life (9.7%, 95% CI: 40,245 - 45,008) were lost due to alcohol. Main causes of alcohol-attributable mortality were injuries at younger ages (15-34 years), with increasing age digestive diseases (mainly liver cirrhosis) and cancers (particularly breast cancers among women). The majority (62%) of all alcohol-attributable deaths was caused by chronic heavy drinking (men: 67%; women: 48 %). CONCLUSION: Alcohol is a major cause of premature mortality in Switzerland. Its impact, among young people mainly via injuries, among men mainly through heavy drinking, calls for a mix of preventive actions targeting chronic heavy drinking, binge drinking and mean consumption.

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QUESTIONS UNDER STUDY: We assessed the occurrence and aetiology of chest pain in primary care practice. These features differ between primary and emergency care settings, where most previous studies have been performed. METHODS: 59 GPs in western Switzerland recorded all consecutive cases presenting with chest pain. Clinical characteristics, laboratory tests and other investigations as well as the diagnoses remaining after 12 months of follow-up were systematically registered. RESULTS: Among 24,620 patients examined during a total duration of 300 weeks of observation, 672 (2.7%) presented with chest pain (52% female, mean age 55 +/- 19(SD)). Most cases, 442 (1.8%), presented new symptoms and in 356 (1.4%) it was the reason for consulting. Over 40 ailments were diagnosed: musculoskeletal chest pain (including chest wall syndrome) (49%), cardiovascular (16%), psychogenic (11%), respiratory (10%), digestive (8%), miscellaneous (2%) and without diagnosis (3%). The three most prevalent diseases were: chest wall syndrome (43%), coronary artery disease (12%) and anxiety (7%). Unstable angina (6), myocardial infarction (4) and pulmonary embolism (2) were uncommon (1.8%). Potentially serious conditions including cardiac, respiratory and neoplasic diseases accounted for 20% of cases. A large number of laboratory tests (42%), referral to a specialist (16%) or hospitalisation (5%) were performed. Twentyfive patients died during follow-up, of which twelve were for a reason directly associated with thoracic pain [cancer (7) and cardiac causes (5)]. CONCLUSIONS: Thoracic pain was present in 2.7% of primary care consultations. Chest wall syndrome pain was the main aetiology. Cardio - vascular emergencies were uncommon. However chest pain deserves full consideration because of the occurrence of potentially serious conditions.

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In marine benthic communities, herbivores consume a considerable proportion of primary producer biomass and, thus, generate selection for the evolution of resistance traits. According to the theory of plant defenses, resistance traits are costly to produce and, consequently, inducible resistance traits are adaptive in conditions of variable herbivory, while in conditions of constant/strong herbivory constitutive resistance traits are selected for. The evolution of resistance plasticity may be constrained by the costs of resistance or lack of genetic variation in resistance. Furthermore, resource allocation to induced resistance may be affected by higher trophic levels preying on herbivores. I studied the resistance to herbivory of a foundation species, the brown alga Fucus vesiculosus. By using factorial field experiments, I explored the effects of herbivores and fish predators on growth and resistance of the alga in two seasons. I explored genetic variation in and allocation costs of resistance traits as well as their chemical basis and their effects on herbivore performance. Using a field experiment I tested if induced resistance spreads via water-borne cues from one individual to another in relevant ecological conditions. I found that in the northern Baltic Sea F. vesiculosus communities, strength of three trophic interactions strongly vary among seasons. The highly synchronized summer reproduction of herbivores promoted their escape from the top-down control of fish predators in autumn. This resulted into large grazing losses in algal stands. In spring, herbivore densities were low and regulated by fish, which, thus,enhanced algal growth. The resistance of algae to herbivory increased with an increase in constitutive phlorotannin content. Furthermore, individuals adopted induced resistance when grazed and when exposed to water-borne cues originating from grazing of conspecific algae both in the laboratory and in field conditions. Induced resistance was adopted to a lesser extent in the presence of fish predators. The results in this thesis indicate that inducible resistance in F. vesiculosus is an adaptation to varying herbivory in the northern Baltic Sea. The costs of resistance and strong seasonality of herbivory have likely contributed to the evolution of this defense strategy. My findings also show that fish predators have positive cascading effects on F. vesiculosus which arise via reduced herbivory but possibly also through reduced resource allocation to resistance. I further found evidence that the spread of resistance via water-borne cues also occurs in ecologically realistic conditions in natural marine sublittoral. Thus, water-borne induction may enable macroalgae to cope with the strong grazing pressure characteristic of marine benthic communities. The results presented here show that seasonality can have pronounced effects on the biotic interactions in marine benthic communities and thereafter influence the evolution of resistance traits in primary producers.