995 resultados para Crash causes


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Support for the theory of ecological speciation requires evidence for ecological divergence between species which directly or indirectly causes reproductive isolation. This study investigates effects of ecological vs. genetic disparity of parental species on the presence of endogenous selection (deformation and mortality rates) and potential sources of exogenous selection (growth rates and hatch timing) on hybrids. Hybrid embryonic development is analysed in a common-garden full-sib cross of three species belonging to two different ecotypes within the Coregonus lavaretus species flock in the central Alpine region of Europe. Although hatch timing was similar across the three species, embryonic growth rates and egg sizes differed between ecotypes. This led to a mismatch between embryonic growth rate and egg size in hybrid crosses that reveals epistasis between the maternal and embryonic genomes and transgressive hatch times that were asynchronous with control crosses. A strong constraint of egg size to embryo size at late development was also evident. We argue that this demonstrates potential for coadaptation of a maternal trait (egg size) with offspring growth rate to be an important source of selection against hybridization between ecotypes with different egg sizes. Implications for the measurement and quantification of early life-history traits affected by this additive relationship, such as hatch day and larval size, are also discussed.

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We report a family with malignant sympathetic paragangliomas (PGL) exhibiting a new type of germline mutation in the succinate dehydrogenase subunit B (SDHB) gene. Two affected brothers, presenting with symptoms at the ages of 25 and 52 yr, suffered from malignant abdominal extraadrenal sympathetic PGL. They died of their disease at ages 43 and 61 yr. Their mother had the same history of signs and symptoms, suggesting a catecholamine-producing tumor at the age of 55 yr. Analysis of the germline DNA from these three patients revealed a novel mutation in exon 4 (H132P) of the SDHB gene. This mutation was absent in 160 control chromosomes. Loss of heterozygosity analysis of the tumors showed a loss of one SDHB allele, and RT-PCR-based expression analysis confirmed the exclusive expression of the mutated allele in both tumors. A review of the published PGL families revealed malignant tumors in seven of 12 well-documented families with SDHB mutation-associated extraadrenal PGL. These findings, as well as findings of the family reported here, suggest a strong causal relationship of SDHB germline mutations with malignant extraadrenal abdominal PGL and imply the necessity of a close follow-up of affected individuals and family members.

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The dominant emotion in violence-threatening situations is confrontational tension/fear (ct/f), which causes most violence to abort, or to be carried out inaccurately and incompetently. For violence to be successful, there must be a pathway around the barrier of ct/f. These pathways include: attacking the weak; audience-oriented staged and controlled fair fights; confrontation-avoiding remote violence; confrontation-avoiding by deception; confrontation-avoiding by absorption in technique. Successfully violent persons, on both sides of the law, are those who have developed these skilled interactional techniques. Since successful violence involves dominating the emotional attention space, only a small proportion of persons can belong to the elite which does most of each type of violence. Macro-violence, including victory and defeat in war, and in struggles of paramilitaries and social movements, is shaped by both material resources and social/emotional resources for maintaining violent organizations and forcing their opponents into organizational breakdown. Social and emotional destruction generally precedes physical destruction.

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There is increasing evidence that species can evolve rapidly in response to environmental change. However, although land use is one of the key drivers of current environmental change, studies of its evolutionary consequences are still fairly scarce, in particular studies that examine land-use effects across large numbers of populations, and discriminate between different aspects of land use. Here, we investigated genetic differentiation in relation to land use in the annual grass Bromus hordeaceus. A common garden study with offspring from 51 populations from three regions and a broad range of land-use types and intensities showed that there was indeed systematic population differentiation of ecologically important plant traits in relation to land use, in particular due to increasing mowing and grazing intensities. We also found strong land-use-related genetic differentiation in plant phenology, where the onset of flowering consistently shifted away from the typical time of management. In addition, increased grazing intensity significantly increased the genetic variability within populations. Our study suggests that land use can cause considerable genetic differentiation among plant populations, and that the timing of land use may select for phenological escape strategies, particularly in monocarpic plant species.

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Carbohydrate-deficient glycoprotein syndrome (CDGS) represents a class of genetic diseases characterized by abnormal N-linked glycosylation. CDGS patients show a large number of glycoprotein abnormalities resulting in dysmorphy, encephalopathy, and other organ disorders. The majority of CDGSs described to date are related to an impaired biosynthesis of dolichyl pyrophosphate-linked Glc3Man9GlcNAc2 in the endoplasmic reticulum. Recently, we identified in four related patients a novel type of CDGS characterized by an accumulation of dolichyl pyrophosphate-linked Man9GlcNAc2. Elaborating on the analogy of this finding with the phenotype of alg5 and alg6 Saccharomyces cerevisiae strains, we have cloned and analyzed the human orthologs to the ALG5 dolichyl phosphate glucosyltransferase and ALG6 dolichyl pyrophosphate Man9GlcNAc2 alpha1,3-glucosyltransferase in four novel CDGS patients. Although ALG5 was not altered in the patients, a C-->T transition was detected in ALG6 cDNA of all four CDGS patients. The mutation cosegregated with the disease in a Mendelian recessive manner. Expression of the human ALG5 and ALG6 cDNA could partially complement the respective S. cerevisiae alg5 and alg6 deficiency. By contrast, the mutant ALG6 cDNA of CDGS patients failed to revert the hypoglycosylation observed in alg6 yeasts, thereby proving a functional relationship between the alanine to valine substitution introduced by the C-->T transition and the CDGS phenotype. The mutation in the ALG6 alpha1,3-glucosyltransferase gene defines an additional type of CDGS, which we propose to refer to as CDGS type-Ic.

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On November 17, 1988, the board of directors of Nestlé AG decided to allow foreign investors to hold Nestlé registered stock, reversing a longstanding practice. This decision had a tremendous impact on the prices of the firm's three classes of common stock, as well as on the prices of several other corporations traded on the Zürich stock exchange. These price changes can be explained by the hypothesis that demand curves slope down.

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BACKGROUND: Valgus hips with increased antetorsion present with lack of external rotation and posterior hip pain that is aggravated with hip extension and external rotation. This may be the result of posterior femoroacetabular impingement (FAI). QUESTIONS/PURPOSES: We asked whether (1) the range of motion (ROM); (2) the location of anterior and posterior bony collision zones; and (3) the prevalence of extraarticular impingement differ between valgus hips with increased antetorsion compared with normal hips and hips with idiopathic FAI. METHODS: Surface models based on CT scan reconstructions of 13 valgus hips with increased antetorsion, 22 hips with FAI, and 27 normal hips were included. Validated three-dimensional collision detection software was used to quantify the simulated hip ROM and the location of impingement on the acetabular and the femoral sides. RESULTS: Hips with coxa valga and antetorsion showed decreased extension, external rotation, and adduction, whereas internal rotation in 90° of flexion was increased. Impingement zones were more anteroinferior on the femur and posteroinferior on the acetabular (pelvic) side; and the zones were more frequently extraarticular, posterior, or to a lesser degree anterior against the inferior iliac spine. We found a higher prevalence of extraarticular impingement for valgus hips with increased antetorsion. CONCLUSIONS: Valgus hips with increased antetorsion predispose to posterior extraarticular FAI and to a lesser degree anteroinferior spine impingement. LEVEL OF EVIDENCE: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

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Mortality of HIV/tuberculosis (TB) patients in Eastern Europe is high. Little is known about their causes of death. This study aimed to assess and compare mortality rates and cause of death in HIV/TB patients across Eastern Europe and Western Europe and Argentina (WEA) in an international cohort study. Mortality rates and causes of death were analysed by time from TB diagnosis (<3 months, 3-12 months or >12 months) in 1078 consecutive HIV/TB patients. Factors associated with TB-related death were examined in multivariate Poisson regression analysis. 347 patients died during 2625 person-years of follow-up. Mortality in Eastern Europe was three- to ninefold higher than in WEA. TB was the main cause of death in Eastern Europe in 80%, 66% and 61% of patients who died <3 months, 3-12 months or >12 months after TB diagnosis, compared to 50%, 0% and 15% in the same time periods in WEA (p<0.0001). In multivariate analysis, follow-up in WEA (incidence rate ratio (IRR) 0.12, 95% CI 0.04-0.35), standard TB-treatment (IRR 0.45, 95% CI 0.20-0.99) and antiretroviral therapy (IRR 0.32, 95% CI 0.14-0.77) were associated with reduced risk of TB-related death. Persistently higher mortality rates were observed in HIV/TB patients in Eastern Europe, and TB was the dominant cause of death at any time during follow-up. This has important implications for HIV/TB programmes aiming to optimise the management of HIV/TB patients and limit TB-associated mortality in this region.

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Deficient activities of multiple steroidogenic enzymes have been reported without and with Antley-Bixler syndrome (ABS), but mutations of corresponding cytochrome P450 enzymes have not been found. We identified mutations in POR, encoding P450 oxidoreductase, the obligate electron donor for these enzymes, in a woman with amenorrhea and three children with ABS, even though knock-out of POR is embryonically lethal in mice. Mutations of POR also affect drug-metabolizing P450 enzymes, explaining the association of ABS with maternal fluconazole ingestion.

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During the last years two studies for the investigation of the etiology of porcine ear necrosis were carried out at the Clinic for Swine of the University of Veterinary Medicine Vienna. In study 1, parameters, which are discussed in this context, were collected by veterinary practitioners by completing specially designed questionnaires in farms with symptoms of the porcine ear necrosis syndrome. In study 2, samples of piglets and feed were collected for laboratory analysis of the most important infectious agents as well as mycotoxins. In the present manuscript, the results of both projects were compared. Even if the selection criteria of both studies differed, the affected age class was comparable (5.5 to ten weeks of life in study 1 and six to ten weeks of life in study 2). The herd-specific prevalence of the porcine ear necrosis syndrome varied considerably with percentages between 2 and 10, respectively, to 100%. The evaluation of questionnaires in study 1 showed that 51% of the farms had problems with cannibalism. Particles of plant material, which were frequently seen on the histologic slides of study 2, could have got into the tissue by chewing the ears of the pen mates or cannibalism. Whereas in study 1 the negative effect of parameters as high pig density, suboptimal climate, missing enrichment material and bad quality of feed and water were considered, in study 2 all these factors were checked at sample collection and ruled out as precursor for cannibalism. In both studies bacterial agents proved to be a crucial co-factor for the expansion of the necroses to deeper tissue layers, whereas viral pathogens were classified less important. In both projects it was not possible to estimate the direct impact of infectious agents and mycotoxins as direct trigger of the necroses as well as their participation as co-factors or precursor in the sense of an immunosuppression or previous damage of blood vessels or tissue.

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BACKGROUND & AIMS Proprotein convertase 1/3 (PC1/3) deficiency, an autosomal-recessive disorder caused by rare mutations in the proprotein convertase subtilisin/kexin type 1 (PCSK1) gene, has been associated with obesity, severe malabsorptive diarrhea, and certain endocrine abnormalities. Common variants in PCSK1 also have been associated with obesity in heterozygotes in several population-based studies. PC1/3 is an endoprotease that processes many prohormones expressed in endocrine and neuronal cells. We investigated clinical and molecular features of PC1/3 deficiency. METHODS We studied the clinical features of 13 children with PC1/3 deficiency and performed sequence analysis of PCSK1. We measured enzymatic activity of recombinant PC1/3 proteins. RESULTS We identified a pattern of endocrinopathies that develop in an age-dependent manner. Eight of the mutations had severe biochemical consequences in vitro. Neonates had severe malabsorptive diarrhea and failure to thrive, required prolonged parenteral nutrition support, and had high mortality. Additional endocrine abnormalities developed as the disease progressed, including diabetes insipidus, growth hormone deficiency, primary hypogonadism, adrenal insufficiency, and hypothyroidism. We identified growth hormone deficiency, central diabetes insipidus, and male hypogonadism as new features of PCSK1 insufficiency. Interestingly, despite early growth abnormalities, moderate obesity, associated with severe polyphagia, generally appears. CONCLUSIONS In a study of 13 children with PC1/3 deficiency caused by disruption of PCSK1, failure of enteroendocrine cells to produce functional hormones resulted in generalized malabsorption. These findings indicate that PC1/3 is involved in the processing of one or more enteric hormones that are required for nutrient absorption.

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To systematically investigate putative causes of non-coronary high-sensitive troponin elevations in patients presenting to a tertiary care emergency department. In this cross-sectional analysis, patients who received serial measurements of high-sensitive troponin T between 1 August 2010 and 31 October 2012 at the Department of Emergency Medicine were included. The following putative causes were considered to be associated with non-acute coronary syndrome-related increases in high-sensitive troponin T: acute pulmonary embolism, renal insufficiency, aortic dissection, heart failure, peri-/myocarditis, strenuous exercise, rhabdomyolysis, cardiotoxic chemotherapy, high-frequency ablation therapy, defibrillator shocks, cardiac infiltrative disorders (e.g., amyloidosis), chest trauma, sepsis, shock, exacerbation of chronic obstructive pulmonary disease, and diabetic ketoacidosis. During the study period a total of 1,573 patients received serial measurements of high-sensitive troponin T. Of these, 175 patients were found to have acute coronary syndrome leaving 1,398 patients for inclusion in the study. In 222 (30 %) of patients, no putative cause described in the literature could be attributed to the elevation in high-sensitive troponin T observed. The most commonly encountered mechanism underlying the troponin T elevation was renal insufficiency that was present in 286 patients (57 %), followed by cerebral ischemia in 95 patients (19 %), trauma in 75 patients (15 %) and heart failure in 41 patients (8 %). Non-acute coronary syndrome-associated elevation of high-sensitive troponin T levels is commonly observed in the emergency department. Renal insufficiency and acute cerebral events are the most common conditions associated with high-sensitive troponin T elevation.