633 research outputs found

    Methods of exposure assessment: lead-contaminated dust in Philadelphia schools.

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    This study was conducted to develop a method that would accurately assess children's exposure to lead in schools in Philadelphia, Pennsylvania. We examined three wipe sample protocols: one included accessible surfaces such as desktops and windowsills, the second included inaccessible surfaces such as the top of filing cabinets and light fixtures, and the third included hand wipes of the study participants. Surface wipes were collected at 10 locations from accessible and inaccessible classroom surfaces (n = 11 at each location) and from the palms of student subjects in the same locations (n = 168). We found a significant difference in lead dust concentrations determined by the three protocols (F = 4.619; 2,27 degrees of freedom; p = 0.019). Lead dust concentrations were significantly elevated at the inaccessible surfaces yet they were uniformly low on the accessible surfaces and the children's palms. These findings were consistent with observed changes in blood lead levels of study participants: after 6 months of exposure to the study locations, 156 of 168 children experienced no change in blood lead level, whereas 12 experienced only a minimal change of 1-2 microg/dL. The mere presence of lead in inaccessible dust in the school environment does not automatically constitute a health hazard because there may not be a completed exposure pathway

    Primary Hepatic Lymphoma: A Retrospective, Multicenter Rare Cancer Network Study.

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    Primary hepatic lymphoma (PHL) is a rare malignancy. We aimed to assess the clinical profile, outcome and prognostic factors in PHL through the Rare Cancer Network (RCN). A retrospective analysis of 41 patients was performed. Median age was 62 years (range, 23-86 years) with a male-to-female ratio of 1.9:1.0. Abdominal pain or discomfort was the most common presenting symptom. Regarding B-symptoms, 19.5% of patients had fever, 17.1% weight loss, and 9.8% night sweats. The most common radiological presentation was multiple lesions. Liver function tests were elevated in 56.1% of patients. The most common histopathological diagnosis was diffuse large B-cell lymphoma (65.9%). Most of the patients received Chop-like (cyclophosphamide, doxorubicin, vincristine, and prednisone) regimens; 4 patients received radiotherapy (dose range, 30.6-40.0 Gy). Median survival was 163 months, and 5- and 10-year overall survival rates were 77 and 59%, respectively. The 5- and 10-year disease-free and lymphoma-specific survival rates were 69, 56, 87 and 70%, respectively. Multivariate analysis revealed that fever, weight loss, and normal hemoglobin level were the independent factors influencing the outcome. In this retrospective multicenter RCN study, patients with PHL had a relatively better prognosis than that reported elsewhere. Multicenter prospective studies are still warranted to establish treatment guidelines, outcome, and prognostic factors

    Orally active antischistosomal early leads identified from the open access malaria box.

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    BACKGROUND: Worldwide hundreds of millions of schistosomiasis patients rely on treatment with a single drug, praziquantel. Therapeutic limitations and the threat of praziquantel resistance underline the need to discover and develop next generation drugs. METHODOLOGY: We studied the antischistosomal properties of the Medicines for Malaria Venture (MMV) malaria box containing 200 diverse drug-like and 200 probe-like compounds with confirmed in vitro activity against Plasmodium falciparum. Compounds were tested against schistosomula and adult Schistosoma mansoni in vitro. Based on in vitro performance, available pharmacokinetic profiles and toxicity data, selected compounds were investigated in vivo. PRINCIPAL FINDINGS: Promising antischistosomal activity (IC50: 1.4-9.5 µM) was observed for 34 compounds against schistosomula. Three compounds presented IC50 values between 0.8 and 1.3 µM against adult S. mansoni. Two promising early leads were identified, namely a N,N'-diarylurea and a 2,3-dianilinoquinoxaline. Treatment of S. mansoni infected mice with a single oral 400 mg/kg dose of these drugs resulted in significant worm burden reductions of 52.5% and 40.8%, respectively. CONCLUSIONS/SIGNIFICANCE: The two candidates identified by investigating the MMV malaria box are characterized by good pharmacokinetic profiles, low cytotoxic potential and easy chemistry and therefore offer an excellent starting point for antischistosomal drug discovery and development

    The Oxytocin Receptor (OXTR) Contributes to Prosocial Fund Allocations in the Dictator Game and the Social Value Orientations Task

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    Background: Economic games observe social decision making in the laboratory that involves real money payoffs. Previously we have shown that allocation of funds in the Dictator Game (DG), a paradigm that illustrates costly altruistic behavior, is partially determined by promoter-region repeat region variants in the arginine vasopressin 1a receptor gene (AVPR1a). In the current investigation, the gene encoding the related oxytocin receptor (OXTR) was tested for association with the DG and a related paradigm, the Social Values Orientation (SVO) task. Methodology/Principal Findings: Association (101 male and 102 female students) using a robust-family based test between 15 single tagging SNPs (htSNPs) across the OXTR was demonstrated with both the DG and SVO. Three htSNPs across the gene region showed significant association with both of the two games. The most significant association was observed with rs1042778 (p = 0.001). Haplotype analysis also showed significant associations for both DG and SVO. Following permutation test adjustment, significance was observed for 2–5 locus haplotypes (p,0.05). A second sample of 98 female subjects was subsequently and independently recruited to play the dictator game and was genotyped for the three significant SNPs found in the first sample. The rs1042778 SNP was shown to be significant for the second sample as well (p = 0.004, Fisher’s exact test). Conclusions: The demonstration that genetic polymorphisms for the OXTR are associated with human prosocial decisio

    Mutations in the potassium channel subunit KCNE1 are associated with early-onset familial atrial fibrillation

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    <p>Abstract</p> <p>Background</p> <p>Atrial fibrillation (AF) is the most common arrhythmia. The potassium current I<sub>Ks </sub>is essential for cardiac repolarization. Gain-of-function mutations in K<sub>V</sub>7.1, the pore-forming α-subunit of the I<sub>Ks </sub>channel, have been associated with AF. We hypothesized that early-onset lone AF is associated with mutations in the I<sub>Ks </sub>channel regulatory subunit KCNE1.</p> <p>Methods</p> <p>In 209 unrelated early-onset lone AF patients (< 40 years) the entire coding sequence of <it>KCNE1 </it>was bidirectionally sequenced. We analyzed the identified KCNE1 mutants electrophysiologically in heterologous expression systems.</p> <p>Results</p> <p>Two non-synonymous mutations G25V and G60D were found in <it>KCNE1 </it>that were not present in the control group (n = 432 alleles) and that have not previously been reported in any publicly available databases or in the exom variant server holding exom data from more than 10.000 alleles. Proband 1 (female, age 45, G25V) had onset of paroxysmal AF at the age of 39 years. Proband 2 (G60D) was diagnosed with lone AF at the age of 33 years. The patient has inherited the mutation from his mother, who also has AF. Both probands had no mutations in genes previously associated with AF. In heterologous expression systems, both mutants showed significant gain-of-function for I<sub>Ks </sub>both with respect to steady-state current levels, kinetic parameters, and heart rate-dependent modulation.</p> <p>Conclusions</p> <p>Mutations in K<sub>V</sub>7.1 leading to gain-of-function of I<sub>Ks </sub>current have previously been described in lone AF, yet this is the first time a mutation in the beta-subunit <it>KCNE1 </it>is associated with the disease. This finding further supports the hypothesis that increased potassium current enhances AF susceptibility.</p

    N-Terminal Arginines Modulate Plasma-Membrane Localization of Kv7.1/KCNE1 Channel Complexes

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    BACKGROUND AND OBJECTIVE: The slow delayed rectifier current (I(Ks)) is important for cardiac action potential termination. The underlying channel is composed of Kv7.1 α-subunits and KCNE1 β-subunits. While most evidence suggests a role of KCNE1 transmembrane domain and C-terminus for the interaction, the N-terminal KCNE1 polymorphism 38G is associated with reduced I(Ks) and atrial fibrillation (a human arrhythmia). Structure-function relationship of the KCNE1 N-terminus for I(Ks) modulation is poorly understood and was subject of this study. METHODS: We studied N-terminal KCNE1 constructs disrupting structurally important positively charged amino-acids (arginines) at positions 32, 33, 36 as well as KCNE1 constructs that modify position 38 including an N-terminal truncation mutation. Experimental procedures included molecular cloning, patch-clamp recording, protein biochemistry, real-time-PCR and confocal microscopy. RESULTS: All KCNE1 constructs physically interacted with Kv7.1. I(Ks) resulting from co-expression of Kv7.1 with non-atrial fibrillation '38S' was greater than with any other construct. Ionic currents resulting from co-transfection of a KCNE1 mutant with arginine substitutions ('38G-3xA') were comparable to currents evoked from cells transfected with an N-terminally truncated KCNE1-construct ('Δ1-38'). Western-blots from plasma-membrane preparations and confocal images consistently showed a greater amount of Kv7.1 protein at the plasma-membrane in cells co-transfected with the non-atrial fibrillation KCNE1-38S than with any other construct. CONCLUSIONS: The results of our study indicate that N-terminal arginines in positions 32, 33, 36 of KCNE1 are important for reconstitution of I(Ks). Furthermore, our results hint towards a role of these N-terminal amino-acids in membrane representation of the delayed rectifier channel complex

    Changes in vegetation and soil characteristics in coastal sand dunes along a gradient of atmospheric nitrogen deposition

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    A field survey was conducted to detect signals of atmospheric nitrogen (N) in 11 dune systems along a nitrogen deposition gradient in the United Kingdom. In the mobile and semi-fixed dunes, above-ground biomass was positively related to N inputs. This increase was largely due to increased height and cover of Ammophila arenaria. In the long term, this increased biomass may lead to increased organic matter accumulation and consequently accelerated soil development. In the fixed dunes, above ground biomass also showed a positive relationship with N inputs as did soil C : N ratio while soil available N was negatively related to N inputs. Plant species richness was negatively related to N inputs. In the dune slacks, while soil and bulk vegetation parameters showed no relationship with N inputs, cover of Carex arenaria and Hypochaeris radicata increased. Site mean Ellenberg N numbers showed no relationship with N deposition either within habitats or across the whole dataset. Neither abundance-weighting nor inclusion of the Siebel numbers for bryophytes improved the relationship. The survey reveals that the relationships of soil and vegetation with atmospheric N deposition vary between sand dune habitats but, despite this variability, clear correlations with N inputs exist. While this survey cannot establish causality, on the basis of the relationships observed we suggest a critical load range of 10 - 20 kg N ha(-1) yr(-1) for coastal sand dunes in the UK

    The Effects of Puerarin on Rat Ventricular Myocytes and the Potential Mechanism

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    Puerarin, a known isoflavone, is commonly found as a Chinese herb medicine. It is widely used in China to treat cardiac diseases such as angina, cardiac infarction and arrhythmia. However, its cardioprotective mechanism remains unclear. In this study, puerarin significantly prolonged ventricular action potential duration (APD) with a dosage dependent manner in the micromolar range on isolated rat ventricular myocytes. However, submicromolar puerarin had no effect on resting membrane potential (RMP), action potential amplitude (APA) and maximal velocity of depolarization (Vmax) of action potential. Only above the concentration of 10 mM, puerarin exhibited more aggressive effect on action potential, and shifted RMP to the positive direction. Millimolar concentrations of puerarin significantly inhibited inward rectified K+ channels in a dosage dependent manner, and exhibited bigger effects upon Kir2.1 vs Kir2.3 in transfected HEK293 cells. As low as micromolar range concentrations of puerarin significantly inhibited Kv7.1 and IKs. These inhibitory effects may due to the direct inhibition of puerarin upon channels not via the PKA-dependent pathway. These results provided direct preclinical evidence that puerarin prolonged APD via its inhibitory effect upon Kv7.1 and IKs, contributing to a better understanding the mechanism of puerarin cardioprotection in the treatment of cardiovascular diseases
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