612 research outputs found

    Body Burden of Dichlorodiphenyl Dichloroethene (DDE) and Childhood Pulmonary Function

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    Longitudinal studies have shown that early life exposure to dichlorodiphenyl dichloroethene (DDE) can lead to growth reduction during childhood and adolescence. In addition, DDE exposure has been linked to respiratory tract infections and an increased risk of asthma in children. Our aim was to understand the relationships between DDE exposure and pulmonary function in children, and, particularly, whether associations are mediated by the height of the children. We used data from an environmental epidemiologic study conducted in central Germany in children aged 8-10 years. The pulmonary function (forced vital capacity, FVC, and forced expiratory volume in one second, FEV1) were measured in three consecutive years. Blood DDE levels were measured at 8 and 10 years. We used linear mixed models for repeated measurements and path analyses to assess the association between blood levels of DDE and pulmonary function measurements. All models were adjusted for confounders. Linear mixed approaches and modelling concurrent effects showed no significant associations. The path analytical models demonstrated that DDE measured at eight years had significant, inverse, indirect, and total effects on FVC at ten years (n = 328; −0.18 L per μg/L of DDE) and FEV1 (n = 328; −0.17 L per μg/L of DDE), mediated through effects of DDE on height and weight. The DDE burden reduces pulmonary function through its diminishing effects on height and weight in children. Further studies are required to test these associations in other samples, preferably from a region with ongoing, high DDT application

    Tight-binding study of high-pressure phase transitions in titanium: alpha to omega and beyond

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    We use a tight-binding total energy method, with parameters determined from a fit to first-principles calculations, to examine the newly discovered gamma phase of titanium. Our parameters were adjusted to accurately describe the alpha Ti-omega Ti phase transition, which is misplaced by density functional calculations. We find a transition from omega Ti to gamma Ti at 102 GPa, in good agreement with the experimental value of 116 GPa. Our results suggest that current density functional calculations will not reproduce the omega Ti-gamma Ti phase transition, but will instead predict a transition from omega Ti to the bcc beta Ti phase.Comment: 3 encapsulated Postscript figures, submitted to Phyical Review Letter

    Candesartan Mediated Amelioration of Cisplatin-Induced Testicular Damage Is Associated with Alterations in Expression Patterns of Nephrin and Podocin

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    Nephrin and podocin are known to be closely related to the pharmacological effects of angiotensin-II receptor blocker (ARB). The objectives of this study were to investigate the role of nephrin and podocin using cisplatin-induced testicular damage and to evaluate the effect of ARB. At first, we evaluated the effects of cisplatin either alone or in combination with ARB candesartan on changes in expression patterns of nephrin and podocin in the rat testes. We then conducted in vitro studies to investigate the effects of angiotensin using cultured Sertoli cells, line TM4. As a result, the expression of nephrin and podocin was shown to localize around the basal membrane of seminiferous tubules. Treatment with cisplatin resulted in a marked decrease in the expression of nephrin and podocin and induced a shift of both proteins from linear to granular expression patterns, accompanying the increased apoptotic index in the testes; these changes were partially restored by the additional administration of candesartan. In vitro studies with TM4 revealed the angiotensin-II mediated expression changes of nephrin and podocin. These findings suggest that candesartan can prevent cisplatin-induced testicular damage by regulating expression patterns of the nephrin-podocin complex in the testes

    Cryptic diversity in the North American Dromochorus tiger beetles (Coleoptera: Carabidae: Cicindelinae): a congruence-based method for species discovery

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    A fundamental problem in biodiversity science is determining the number of species in any taxon, and there is a growing awareness that cryptic diversity contributes to this problem – even in well-studied groups. Discovering cryptic species requires several lines of evidence to elucidate congruent patterns across data-types, and distinguish unrecognized species. Tiger beetles are among the most well-studied insect groups; yet few new North American species have been described since the mid-20th century, suggesting that that the number of morphologically distinct species is reaching an asymptote. We explore the possibility that more species exist in the fauna as cryptic species, by analysing a broad geographic sample of all species in the genus Dromochorus. We employ a ‘taxonomic congruence’ approach, where we first generate species hypotheses from patterns of reciprocal monophyly across the mitochondrial and nuclear datasets, and test these hypotheses through congruence with population structure, morphological measures and ecological divergence. We find broad congruence that supports eight species of Dromochorus, more than doubling the known diversity. We also validate a previously ambiguous taxon, and re-describe previously named species. Lastly, we identify new diagnostic morphological characters, include an updated dichotomous key and provide updated natural history/ecological characteristics for the genus and individual species

    Argatroban During Percutaneous Transluminal Coronary Angioplasty: Results of a Dose-Verification Study.

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    Background. Thrombin is a key enzyme in thrombogenesis. In animals, specific antithrombotic therapy at the time of coronary angioplasty reduced the incidence of subacute occlusion and inhibited the restenosis response. Argatroban is a highly selective synthetic thrombin antagonist that binds in a competitive manner. This is a report of a dose-verification study, assessing the safety and feasibility of intravenous Argatroban administration in patients undergoing percutaneous transluminal coronary angioplasty. Methods. Before angioplasty an intravenous bolus of 30 g/kg argatroban was administered, followed by a continuous infusion of 3.5 g/kg/min for 72 hours. Bolus injection was repeated, and the infusion rate was increased in order to achieve an activated coagulation time (ACT) of over 300 seconds. Following interim analysis, the bolus and initial infusion rate for the subsequent treatment groups was determined. Study endpoints were the occurrence of adverse events, coagulation tests, and qualitative angiogram reading. Patients were monitored by continuous 12-lead electrocardiographic recording over 24 hours, and underwent control angiography 18–24 hours following angioplasty. Results. Four treatment groups, comprised of 2, 8, 9, and 11 patients, respectively, were studied. The first two patients were excluded from analysis, since the initial dose was ineffective to attain an ACT-authorizing coronary angioplasty. The group with the highest dosage received a 250 g/kg intravenous bolus of argatroban, followed by a 4 hour infusion of 15 g/kg/min. At 4 hours the infusion rate was lowered to 3.8 g/kg/min and was continued for 68 hours without adjustment for catheter removal. The adverse event profile included myocardial infarction, aortocoronary bypass graft, bailout procedures, and repeat coronary angioplasty. Thrombin-time (TT), activated partial thromboplastin time (APTT), and prothrombin time (PT) were significantly related to argatroban plasma concentration, as demonstrated by regression analyses (R-square 0.64, 0.71, and 0.84, respectively). Prothrombin fragments 1 and 2 and thrombin-antithrombin III complex did not fit into a mathematical model, but showed slightly increased levels after reduction or cessation of the infusion rate. Conclusions. This dose-verification study, including 30 patients at four dose levels, indicated that argatroban infusion in coronary angioplasty patients can be administered safely, and results in an adequate and predictable level of anticoagulation

    Community views on ‘Can perinatal services safely identify Aboriginal and Torres Strait Islander parents experiencing complex trauma?’

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    Family and extended kinship systems which nurture healthy, happy children are central to Aboriginal and Torres Strait Islander cultures. Since colonisation, Aboriginal and Torres Strait Islander communities have been impacted by intergenerational cycles of trauma, stemming from colonial violence, genocidal policies and discrimination, including the forced removal of children from their families. Becoming a parent offers a unique life-course opportunity for trauma recovery and preventing intergenerational trauma. However, identifying or ‘recognising’ complex trauma carries significant risk of harm for Aboriginal and Torres Strait Islander parents due to reactive prenatal child protection involvement potentially compounding experiences of trauma, and limited benefits due to lack of culturally appropriate support. The Aboriginal-led participatory Healing the Past by Nurturing the Future project aims to co-design safe, accessible and feasible perinatal awareness, recognition, assessment and support strategies for Aboriginal and Torres Strait Islander parents experiencing complex trauma. This paper presents views of 38 workshop participants to determine prerequisites for ensuring benefits outweigh risks of assessment to safely recognise parents experiencing complex trauma, consistent with screening criteria. Six essential elements were identified from thematic analysis: high-quality holistic care; cultural, social and emotional safety; empowerment, choice and control; flexible person-centred approaches; trusting relationships; and sensitive, skilled communication

    Determining weight-bearing tissue condition using peak reactive hyperemia response trend and ultrasonographic features: implications for pressure ulcer prevention

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    Frequent repositioning is important to prevent pressure ulcer (PU) development, by relieving pressure and recovering damages on skin areas induced by repetitive loading. Although repositioning is the gold standard to prevent PU, there is currently no strategy for determining tissue condition under preventive approaches. In this study, the peak reactive hyperemia (RH) trends and ultrasonographic (US) features are compared with the tissue condition under histopathological examination to determine the potential use of these features in determining the tissue condition noninvasively. Twenty-one male Sprague–Dawley rats (seven per group), with body weight of 385–485 g, were categorized into three groups and subjected to different recovery times, each with three repetitive loading cycles at skin tissues above of right trochanter area. The first, second, and third groups were subjected to short (3 minutes), moderate (10 minutes), and prolonged (40 minutes) recovery, respectively, while applying fixed loading time and pressure (10 minutes and 50 mmHg, respectively), to provide different degree of recovery and tissue conditions (tissue damage and tissue recovery). Peak RH was measured in the three cycles to determine RH trend (increasing, decreasing, and inconsistent). All rat tissues were evaluated using ultrasound at pre- and post-experiment and rated by two raters to categorize the severity of tissue changes (no, mild, moderate, and severe). The tissue condition was also evaluated using histopathological examination to distinguish between normal and abnormal tissues. Most of the samples with increasing RH trend is related to abnormal tissue (71%); while inconsistent RH trends is more related to normal tissue (82%). There is no relationship between the tissue conditions evaluated under ultrasonographic and histopathological examination. Peak RH trend over repetitive loading may serve as a new feature for determining the tissue condition that leading to pressure ulcer

    Co-Evolution of quasispecies: B-cell mutation rates maximize viral error catastrophes

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    Co-evolution of two coupled quasispecies is studied, motivated by the competition between viral evolution and adapting immune response. In this co-adaptive model, besides the classical error catastrophe for high virus mutation rates, a second ``adaptation-'' catastrophe occurs, when virus mutation rates are too small to escape immune attack. Maximizing both regimes of viral error catastrophes is a possible strategy for an optimal immune response, reducing the range of allowed viral mutation rates to a minimum. From this requirement one obtains constraints on B-cell mutation rates and receptor lengths, yielding an estimate of somatic hypermutation rates in the germinal center in accordance with observation.Comment: 4 pages RevTeX including 2 figure
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