105 research outputs found

    Response of Mouse Lung Air-Blood Barrier to X-Irradiation: Ultrastructural and Stereological Analysis

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    Male mice of the Balb/c strain were exposed, at an age of three months, to a single dose of 10 or 20 Gy on the right hemithorax. At 3, 4, 6, 9 and 12 months after exposure, lungs were processed for electron microscopy following a standardized procedure in order to allow stereological analysis. By this method, the arithmetical mean thickness and, the air-blood barrier mean thickness in the lung parenchyma was shown to increase quickly with time by oedemization and fibrinization of the septal space. The ratio endothelium/epithelium surfaces (Sr/SF) gradually decreased by reduction of both surfaces but this was more marked for Si. The endothelium and epithelium were both highly damaged. Quantitative results indicate that damage to the epithelial cells and mainly to type II, appear at the same time as damage to the endothelium. From the time lapse quantitation it is not possible to determine which one plays the predominant role in the radiation pneumonitis. The strong reaction of the basement membrane and mainly of the interstitial cells could play a decisive role in the evolution of the illness

    Ultrastructural Features of Osteoclasts In Situ

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    The morphology of in situ osteoclasts on endocortical surfaces of the femoral midshaft was examined by scanning electron microscopy. Mice were perfusion fixed and bone marrow plugs were flushed out of femoral diaphyseal cylinders. The bones were split longitudinally and the endocortical surfaces examined. This method left on the bone surface most of the endosteal cells in their natural, in situ shape and position. Most of the bone surface was lined by contiguous bone lining cells covering resting bone surfaces, making a clear physical barrier between the bone and marrow compartments. On resorption surfaces, which were characterized by excavation cavities, osteoclasts were very polymorphic and spread on the bone surface, extending large pseudopods. The in vivo morphology of individual osteoclasts appears somewhat similar to that described by other investigators on calvaria surfaces and for isolated osteoclasts adherent to artificial substrates. In the resorption domains, osteoclasts appeared to be connected with adjacent osteoclasts, suggesting that the cells form a functional syncytium in resorption areas

    Структура и твердость титанового сплава ВТ6, изготовленного методом аддитивных технологий

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    Работа посвящена новой отрасли производства и материаловедения – исследованию материалов, полученных методами аддитивного производства. Целью данной работы являлось сравнительный анализ различий в структуре, механических свойствах и взаимодействии с водородом титанового сплава ВТ6, полученного традиционным методом и методом аддитивного производства (EBM). В работе получены результаты, свидетельствующие об отличии свойств материалов, полученных традиционными методами и методами аддитивного производства.The work is devoted to a new branch of production and materials science - the study of materials obtained by additive production methods. The purpose of this work was a comparative analysis of differences in the structure, mechanical properties and interaction with hydrogen of a titanium alloy VT6 obtained by the traditional method and the additive production method (EBM). The results obtained in the work indicate the difference between the properties of materials obtained by traditional methods and additive production methods

    Do Parents Recognize Autistic Deviant Behavior Long before Diagnosis? Taking into Account Interaction Using Computational Methods

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    BACKGROUND: To assess whether taking into account interaction synchrony would help to better differentiate autism (AD) from intellectual disability (ID) and typical development (TD) in family home movies of infants aged less than 18 months, we used computational methods. METHODOLOGY AND PRINCIPAL FINDINGS: First, we analyzed interactive sequences extracted from home movies of children with AD (N = 15), ID (N = 12), or TD (N = 15) through the Infant and Caregiver Behavior Scale (ICBS). Second, discrete behaviors between baby (BB) and Care Giver (CG) co-occurring in less than 3 seconds were selected as single interactive patterns (or dyadic events) for analysis of the two directions of interaction (CG→BB and BB→CG) by group and semester. To do so, we used a Markov assumption, a Generalized Linear Mixed Model, and non negative matrix factorization. Compared to TD children, BBs with AD exhibit a growing deviant development of interactive patterns whereas those with ID rather show an initial delay of development. Parents of AD and ID do not differ very much from parents of TD when responding to their child. However, when initiating interaction, parents use more touching and regulation up behaviors as early as the first semester. CONCLUSION: When studying interactive patterns, deviant autistic behaviors appear before 18 months. Parents seem to feel the lack of interactive initiative and responsiveness of their babies and try to increasingly supply soliciting behaviors. Thus we stress that credence should be given to parents' intuition as they recognize, long before diagnosis, the pathological process through the interactive pattern with their child

    Association of the PHACTR1/EDN1 genetic locus with spontaneous coronary artery dissection

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    Background: Spontaneous coronary artery dissection (SCAD) is an increasingly recognized cause of acute coronary syndromes (ACS) afflicting predominantly younger to middle-aged women. Observational studies have reported a high prevalence of extracoronary vascular anomalies, especially fibromuscular dysplasia (FMD) and a low prevalence of coincidental cases of atherosclerosis. PHACTR1/EDN1 is a genetic risk locus for several vascular diseases, including FMD and coronary artery disease, with the putative causal noncoding variant at the rs9349379 locus acting as a potential enhancer for the endothelin-1 (EDN1) gene. Objectives: This study sought to test the association between the rs9349379 genotype and SCAD. Methods: Results from case control studies from France, United Kingdom, United States, and Australia were analyzed to test the association with SCAD risk, including age at first event, pregnancy-associated SCAD (P-SCAD), and recurrent SCAD. Results: The previously reported risk allele for FMD (rs9349379-A) was associated with a higher risk of SCAD in all studies. In a meta-analysis of 1,055 SCAD patients and 7,190 controls, the odds ratio (OR) was 1.67 (95% confidence interval [CI]: 1.50 to 1.86) per copy of rs9349379-A. In a subset of 491 SCAD patients, the OR estimate was found to be higher for the association with SCAD in patients without FMD (OR: 1.89; 95% CI: 1.53 to 2.33) than in SCAD cases with FMD (OR: 1.60; 95% CI: 1.28 to 1.99). There was no effect of genotype on age at first event, P-SCAD, or recurrence. Conclusions: The first genetic risk factor for SCAD was identified in the largest study conducted to date for this condition. This genetic link may contribute to the clinical overlap between SCAD and FMD

    Trace elements in hemodialysis patients: a systematic review and meta-analysis

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    <p>Abstract</p> <p>Background</p> <p>Hemodialysis patients are at risk for deficiency of essential trace elements and excess of toxic trace elements, both of which can affect health. We conducted a systematic review to summarize existing literature on trace element status in hemodialysis patients.</p> <p>Methods</p> <p>All studies which reported relevant data for chronic hemodialysis patients and a healthy control population were eligible, regardless of language or publication status. We included studies which measured at least one of the following elements in whole blood, serum, or plasma: antimony, arsenic, boron, cadmium, chromium, cobalt, copper, fluorine, iodine, lead, manganese, mercury, molybdenum, nickel, selenium, tellurium, thallium, vanadium, and zinc. We calculated differences between hemodialysis patients and controls using the differences in mean trace element level, divided by the pooled standard deviation.</p> <p>Results</p> <p>We identified 128 eligible studies. Available data suggested that levels of cadmium, chromium, copper, lead, and vanadium were higher and that levels of selenium, zinc and manganese were lower in hemodialysis patients, compared with controls. Pooled standard mean differences exceeded 0.8 standard deviation units (a large difference) higher than controls for cadmium, chromium, vanadium, and lower than controls for selenium, zinc, and manganese. No studies reported data on antimony, iodine, tellurium, and thallium concentrations.</p> <p>Conclusion</p> <p>Average blood levels of biologically important trace elements were substantially different in hemodialysis patients, compared with healthy controls. Since both deficiency and excess of trace elements are potentially harmful yet amenable to therapy, the hypothesis that trace element status influences the risk of adverse clinical outcomes is worthy of investigation.</p

    Passa-se uma engenhoca: ou como se faziam transações com terras, engenhos e crédito em mercados locais e imperfeitos (freguesia de Campo Grande, Rio de Janeiro, séculos XVIII e XIX)

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    Radiation induced Apoptosis in the Developing Brain

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    The developing brain is very sensitive to ionizing radiation. The detrimental effect of radiation has typically been attributed to its ability to cause DNA damage. Fortunately cells possess complex and efficient DNA repair mechanisms capable of repairing most genomic damage. However, occasionally, damaged DNA is misrepaired or incompletely repaired. This can result in the triggering of apoptotic cell response. In the developing nervous system, apoptosis results in naturally occurring cell death, a process that eliminates neurons that have made faulty synapses or have not reached appropriate targets. Apoptosis is also a response to many stimuli like ionizing radiation and factors into many neurodegenerative diseases. The aim of this work is to understand the effect of low dose ionizing radiation on brain development and to estimate the radiation induced apoptotic response. Apoptosis requires the expression of several specific genes among which the Trp53 gene. The analysis of those expressed genes by quantitative PCR and by DNA microchips array will help in unraveling the molecular aspect of the radiation induced apoptosis. We performed qPCR and cDNA microarray analysis at embryonic day E 13 after in utero exposure to 50cGy x-radiation of both wild-type and p53 knock-out mice in irradiated and non-irradiated conditions. Only genes with identified function and a minimal 2 fold amplification were further considered. Our results indicate that genes activated in p53 +/+ and in p53-/- mice appear quite different. It revealed that the main activated pathways in irradiated wild type embryos are involved in the regulation of a p53 mediated pathway that may lead to cell cycle arrest and increased level of apoptosis. To define whether the transcriptional radiation response was solely p53 mediated, we analyzed the expression of cell cycle regulating genes in a Trp53 null mutant. The modulated expression of cell cycle regulating genes such as cyclins and Cdk genes indicated the induction of a cell cycle arrest, without evidence for the onset of apoptosis. Additional gene expression studies have shown that various E2F transcription factors may be involved in this event. Together these results provide a detailed view of the different p53-related mechanisms that are triggered in response to ionizing radiation in the developing brain
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