464 research outputs found

    Constrictive pericarditis is an easily overlooked cause of right heart failure: a case report

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    We describe a patient who suffered progressive right heart failure of unknown aetiology, despite a lengthy series of hospital investigations. Constrictive pericarditis had not been suspected during life, and was ultimately diagnosed as an autopsy finding. The salient clinical features and confirmatory investigations for this unusual disorder are reviewed. The case reminds us to consider the possibility of constrictive pericarditis in patients with unexplained chronic right heart failure, so that prompt investigation and treatment can be instigated

    Nutritional Factors and Susceptibility to Arsenic-Caused Skin Lesions in West Bengal, India

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    There has been widespread speculation about whether nutritional deficiencies increase the susceptibility to arsenic health effects. This is the first study to investigate whether dietary micronutrient and macronutrient intake modulates the well-established human risk of arsenic-induced skin lesions, including alterations in skin pigmentation and keratoses. The study was conducted in West Bengal, India, which along with Bangladesh constitutes the largest population in the world exposed to arsenic from drinking water. In this case–control study design, cases were patients with arsenic-induced skin lesions and had < 500 μg/L arsenic in their drinking water. For each case, an age- and sex-matched control was selected from participants of a 1995–1996 cross-sectional survey, whose drinking water at that time also contained < 500 μg/L arsenic. Nutritional assessment was based on a 24-hr recall for major dietary constituents and a 1-week recall for less common constituents. Modest increases in risk were related to being in the lowest quintiles of intake of animal protein [odds ratio (OR) = 1.94; 95% confidence interval (CI), 1.05–3.59], calcium (OR = 1.89; 95% CI, 1.04–3.43), fiber (OR = 2.20; 95% CI, 1.15–4.21), and folate (OR = 1.67; 95% CI, 0.87–3.2). Conditional logistic regression suggested that the strongest associations were with low calcium, low animal protein, low folate, and low fiber intake. Nutrient intake was not related to arsenic exposure. We conclude that low intake of calcium, animal protein, folate, and fiber may increase susceptibility to arsenic-caused skin lesions. However, in light of the small magnitude of increased risks related to these dietary deficiencies, prevention should focus on reducing exposure to arsenic

    Absorption Enhancement in Peridinin–Chlorophyll–Protein Light-Harvesting Complexes Coupled to Semicontinuous Silver Film

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    We report on experimental and theoretical studies of plasmon-induced effects in a hybrid nanostructure composed of light-harvesting complexes and metallic nanoparticles in the form of semicontinuous silver film. The results of continuous-wave and time-resolved spectroscopy indicate that absorption of the light-harvesting complexes is strongly enhanced upon coupling with the metallic film spaced by 25 nm of a dielectric silica layer. This conclusion is corroborated by modeling, which confirms the morphology of the silver island film

    Tetralogy of Fallot

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    Tetralogy of Fallot is a congenital cardiac malformation that consists of an interventricular communication, also known as a ventricular septal defect, obstruction of the right ventricular outflow tract, override of the ventricular septum by the aortic root, and right ventricular hypertrophy

    4D cardiovascular magnetic resonance velocity mapping of alterations of right heart flow patterns and main pulmonary artery hemodynamics in tetralogy of Fallot

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    <p>Abstract</p> <p>Background</p> <p>To assess changes in right heart flow and pulmonary artery hemodynamics in patients with repaired Tetralogy of Fallot (rTOF) we used whole heart, four dimensional (4D) velocity mapping (VM) cardiovascular magnetic resonance (CMR).</p> <p>Methods</p> <p>CMR studies were performed in 11 subjects with rTOF (5M/6F; 20.1 ± 12.4 years) and 10 normal volunteers (6M/4F; 34.2 ± 13.4 years) on clinical 1.5T and 3.0T MR scanners. 4D VM-CMR was performed using PC VIPR (Phase Contrast Vastly undersampled Isotropic Projection Reconstruction). Interactive streamline and particle trace visualizations of the superior and inferior vena cava (IVC and SVC, respectively), right atrium (RA), right ventricle (RV), and pulmonary artery (PA) were generated and reviewed by three experienced readers. Main PA net flow, retrograde flow, peak flow, time-to-peak flow, peak acceleration, resistance index and mean wall shear stress were quantified. Differences in flow patterns between the two groups were tested using Fisher's exact test. Differences in quantitative parameters were analyzed with the Kruskal-Wallis rank sum test.</p> <p>Results</p> <p>4D VM-CMR was successfully performed in all volunteers and subjects with TOF. Right heart flow patterns in rTOF subjects were characterized by (a) greater SVC/IVC flow during diastole than systole, (b) increased vortical flow patterns in the RA and in the RV during diastole, and (c) increased helical or vortical flow features in the PA's. Differences in main PA retrograde flow, resistance index, peak flow, time-to-peak flow, peak acceleration and mean wall shear stress were statistically significant.</p> <p>Conclusions</p> <p>Whole heart 4D VM-CMR with PC VIPR enables detection of both normal and abnormal right heart flow patterns, which may allow for comprehensive studies to evaluate interdependencies of post-surgically altered geometries and hemodynamics.</p

    Genetic integrity of the human Y chromosome exposed to groundwater arsenic

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    <p>Abstract</p> <p>Background</p> <p>Arsenic is a known human carcinogen reported to cause chromosomal deletions and genetic anomalies in cultured cells. The vast human population inhabiting the Ganges delta in West Bengal, India and Bangladesh is exposed to critical levels of arsenic present in the groundwater. The genetic and physiological mechanism of arsenic toxicity in the human body is yet to be fully established. In addition, lack of animal models has made work on this line even more challenging.</p> <p>Methods</p> <p>Human male blood samples were collected with their informed consent from 5 districts in West Bengal having groundwater arsenic level more than 50 μg/L. Isolation of genomic DNA and preparation of metaphase chromosomes was done using standard protocols. End point PCR was performed for established sequence tagged sites to ascertain the status of recombination events. Single nucleotide variants of candidate genes and amplicons were carried out using appropriate restriction enzymes. The copy number of DYZ1 array per haploid genome was calculated using real time PCR and its chromosomal localization was done by fluorescence in-situ hybridization (FISH).</p> <p>Results</p> <p>We studied effects of arsenic exposure on the human Y chromosome in males from different areas of West Bengal focusing on known recombination events (P5-P1 proximal; P5-P1 distal; gr/gr; TSPY-TSPY, b1/b3 and b2/b3), single nucleotide variants (SNVs) of a few candidate Y-linked genes (DAZ, TTY4, BPY2, GOLGA2LY) and the amplicons of AZFc region. Also, possible chromosomal reorganization of DYZ1 repeat arrays was analyzed. Barring a few microdeletions, no major changes were detected in blood DNA samples. SNV analysis showed a difference in some alleles. Similarly, DYZ1 arrays signals detected by FISH were found to be affected in some males.</p> <p>Conclusions</p> <p>Our Y chromosome analysis suggests that the same is protected from the effects of arsenic by some unknown mechanisms maintaining its structural and functional integrities. Thus, arsenic effects on the human body seem to be different compared to that on the cultured cells.</p

    An ecological quantification of the relationships between water, sanitation and infant, child, and maternal mortality

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    <p>Abstract</p> <p>Background</p> <p>Water and sanitation access are known to be related to newborn, child, and maternal health. Our study attempts to quantify these relationships globally using country-level data: How much does improving access to water and sanitation influence infant, child, and maternal mortality?</p> <p>Methods</p> <p>Data for 193 countries were abstracted from global databases (World Bank, WHO, and UNICEF). Linear regression was used for the outcomes of under-five mortality rate and infant mortality rate (IMR). These results are presented as events per 1000 live births. Ordinal logistic regression was used to compute odds ratios for the outcome of maternal mortality ratio (MMR).</p> <p>Results</p> <p>Under-five mortality rate decreased by 1.17 (95%CI 1.08-1.26) deaths per 1000, <it>p </it>< 0.001, for every quartile increase in population water access after adjustments for confounders. There was a similar relationship between quartile increase of sanitation access and under-five mortality rate, with a decrease of 1.66 (95%CI 1.11-1.32) deaths per 1000, <it>p </it>< 0.001. Improved water access was also related to IMR, with the IMR decreasing by 1.14 (95%CI 1.05-1.23) deaths per 1000, <it>p </it>< 0.001, with increasing quartile of access to improved water source. The significance of this relationship was retained with quartile improvement in sanitation access, where the decrease in IMR was 1.66 (95%CI 1.11-1.32) deaths per 1000, <it>p </it>< 0.001. The estimated odds ratio that increased quartile of water access was significantly associated with increased quartile of MMR was 0.58 (95%CI 0.39-0.86), <it>p </it>= 0.008. The corresponding odds ratio for sanitation was 0.52 (95%CI 0.32-0.85), <it>p </it>= 0.009, both suggesting that better water and sanitation were associated with decreased MMR.</p> <p>Conclusions</p> <p>Our analyses suggest that access to water and sanitation independently contribute to child and maternal mortality outcomes. If the world is to seriously address the Millennium Development Goals of reducing child and maternal mortality, then improved water and sanitation accesses are key strategies.</p
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