14 research outputs found

    ANTI-MOSQUITO BEHAVIOR OF ADULT AND JUVENILE WHITE-FOOTED MICE (PEROMYSCUS LEUCOPUS) (TREEHOLE MOSQUITO, AEDES TRISERIATUS, EPIDEMIOLOGY)

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    Rodents seldom are identified as hosts for mosquitoes, based on serological analysis of bloodmeals. However, due to limited survey and lack of sensitivity in most bloodmeal analyses, host species can be misrepresented or undetected. Knowledge of behavior of a potential host species can complement results of bloodmeal analysis, because active vertebrates may prevent mosquito feeding and thus rarely serve as hosts. The objectives of this study were to characterize anti-mosquito behavior in the white-footed mouse (Peromyscus leucopus noveboracensis) and to examine effectiveness of such behavior in mice based on age, prior exposure to mosquitoes, and immediate environment. I used wild-stock Aedes triseriatus mosquitoes, reared in lab, in experiments with four groups of mice: (1) wild-caught adult males in a barren enclosure; (2) wild-caught adult males in an enclosure with seeds and nest material that could be manipulated, simulating natural activity; (3) adult males from a lab colony of P. leucopus; and (4) wild-stock, lab-reared juveniles with or without practice (prior exposure to mosquitoes). I used an electronic event recorder to monitor grooming, exploring, resting, and anti-mosquito actions. I observed each mouse without and then with mosquitoes. I then anesthetized each mouse to verify that lack of mosquito feeding success on the non-anesthetized (active) mouse was due to mouse behavior. Results indicated that the role of prior exposure to mosquitoes was minimal. Wild adult mice maintained defense while handling and eating seeds, implying that anti-mosquito behavior probably is an integral part of their activity in nature. Certain actions, such as ear-flick, occurred almost exclusively when mosquitoes were present. Juveniles usually caught, killed, and ate more mosquitoes than did adults. Individuality of mouse behavior affected the outcome of mouse-mosquito interactions. All mice, except one, had highly effective defense against mosquitoes. Therefore, P. leucopus probably rarely serves as host for mosquitoes in nature and, thus, as host or reservoir for mosquito-borne diseases

    Genetic association study of QT interval highlights role for calcium signaling pathways in myocardial repolarization.

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    The QT interval, an electrocardiographic measure reflecting myocardial repolarization, is a heritable trait. QT prolongation is a risk factor for ventricular arrhythmias and sudden cardiac death (SCD) and could indicate the presence of the potentially lethal mendelian long-QT syndrome (LQTS). Using a genome-wide association and replication study in up to 100,000 individuals, we identified 35 common variant loci associated with QT interval that collectively explain ∌8-10% of QT-interval variation and highlight the importance of calcium regulation in myocardial repolarization. Rare variant analysis of 6 new QT interval-associated loci in 298 unrelated probands with LQTS identified coding variants not found in controls but of uncertain causality and therefore requiring validation. Several newly identified loci encode proteins that physically interact with other recognized repolarization proteins. Our integration of common variant association, expression and orthogonal protein-protein interaction screens provides new insights into cardiac electrophysiology and identifies new candidate genes for ventricular arrhythmias, LQTS and SCD

    52 Genetic Loci Influencing Myocardial Mass.

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    BACKGROUND: Myocardial mass is a key determinant of cardiac muscle function and hypertrophy. Myocardial depolarization leading to cardiac muscle contraction is reflected by the amplitude and duration of the QRS complex on the electrocardiogram (ECG). Abnormal QRS amplitude or duration reflect changes in myocardial mass and conduction, and are associated with increased risk of heart failure and death. OBJECTIVES: This meta-analysis sought to gain insights into the genetic determinants of myocardial mass. METHODS: We carried out a genome-wide association meta-analysis of 4 QRS traits in up to 73,518 individuals of European ancestry, followed by extensive biological and functional assessment. RESULTS: We identified 52 genomic loci, of which 32 are novel, that are reliably associated with 1 or more QRS phenotypes at p < 1 × 10(-8). These loci are enriched in regions of open chromatin, histone modifications, and transcription factor binding, suggesting that they represent regions of the genome that are actively transcribed in the human heart. Pathway analyses provided evidence that these loci play a role in cardiac hypertrophy. We further highlighted 67 candidate genes at the identified loci that are preferentially expressed in cardiac tissue and associated with cardiac abnormalities in Drosophila melanogaster and Mus musculus. We validated the regulatory function of a novel variant in the SCN5A/SCN10A locus in vitro and in vivo. CONCLUSIONS: Taken together, our findings provide new insights into genes and biological pathways controlling myocardial mass and may help identify novel therapeutic targets

    White matter volume and anisotropy in preterm children: A pilot study of neurocognitive correlates

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    The objectives of this study were to evaluate the differences in whole brain white matter (WM) volume and anisotropy between preterm and term children and to determine the relationships with cognitive outcome. Twenty-five low birth weight (BW), preterm, neurologically normal children between 8.8 and 11.5 y of age were recruited for volumetric and diffusion-tensor magnetic resonance imaging (DTI), together with 13 age-matched term control subjects. Subsequent intelligence quotient (IQ) testing was performed for 21 preterm children within 6 mo of imaging studies. We computed the mean volume and fractional anisotropy (FA) of the whole brain WM and compared the differences between the two groups. Mean WM volume and FA were significantly lower in the preterm group (p = 0.014 and p < 0.001, respectively). Multiple regression analysis found both WM volume and FA to be independent variables significantly affecting full scale IQ (FSIQ) (r = 0.407, p = 0.021 and r = 0.496, p = 0.005, respectively) after adjusting for BW, gestational age (GA), and gender. In the evaluation of the whole brain WM of preterm children, we found that both volume and FA remain reduced at late childhood with both parameters significantly affecting long-term cognitive outcome. © International Pediatrics Research Foundation, Inc. 2007. All Rights Reserved.link_to_subscribed_fulltex
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