188 research outputs found

    \u27Candidatus Xenohaliotis californiensis\u27, a newly described pathogen of abalone, Haliotis spp., along the west coast of North America

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    Withering syndrome is a fatal disease of wild and cultured abalone. Haliotis spp., that inhabit the west coast of North America. The aetiological agent of withering syndrome has recently been identified as a member of the family Rickettsiaceae in the order Rickettsiales. Using a combination of morphological, serological, life history and genomic (16S rDNA) characterization. we have identified this bacterium as a unique taxon and propose the provisional status of \u27Candidatus Xenohaliotis californiensis\u27, The Gram-negative. obligate intracellular pleomorphic bacterium is found within membrane-bound vacuoles in the cytoplasm of abalone gastrointestinal epithelial cells. The bacterium is not cultivable on synthetic media or in fish cell lines (e.g. CHSE-214) and may be controlled by tetracyclines (oxytetracycline) but not by chloramphenicol, clarithromycin or sarafloxicin. Phylogenetic analysis based on the 16S rDNA of \u27Candidatus Xenohaliotis californiensis\u27 places it in the alpha-subclass of the class Proteobacteria but not to the four recognized subtaxa of the alpha-Proteobacteria (alpha-1, alpha-2, alpha-3 and alpha-4). The bacterium can be detected in tissue squashes stained with propidium iodide, microscopic examination of stained tissue sections, PCR or in situ hybridization. \u27Candidatus Xenohaliotis californiensis\u27 can be differentiated from other closely related alpha-Proteobacteria by its unique 16S rDNA sequence

    Patient recruitment to a randomized clinical trial of behavioral therapy for chronic heart failure

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    BACKGROUND: Patient recruitment is one of the most difficult aspects of clinical trials, especially for research involving elderly subjects. In this paper, we describe our experience with patient recruitment for the behavioral intervention randomized trial, "The relaxation response intervention for chronic heart failure (RRCHF)." Particularly, we identify factors that, according to patient reports, motivated study participation. METHODS: The RRCHF was a three-armed, randomized controlled trial designed to evaluate the efficacy and cost of a 15-week relaxation response intervention on veterans with chronic heart failure. Patients from the Veterans Affairs (VA) Boston Healthcare System in the United States were recruited in the clinic and by telephone. Patients' reasons for rejecting the study participation were recorded during the screening. A qualitative sub-study in the trial consisted of telephone interviews of participating patients about their experiences in the study. The qualitative study included the first 57 patients who completed the intervention and/or the first follow-up outcome measures. Factors that distinguished patients who consented from those who refused study participation were identified using a t-test or a chi-square test. The reason for study participation was abstracted from the qualitative interview. RESULTS: We successfully consented 134 patients, slightly more than our target number, in 27 months. Ninety-five of the consented patients enrolled in the study. The enrollment rate among the patients approached was 18% through clinic and 6% through telephone recruitment. The most commonly cited reason for declining study participation given by patients recruited in the clinic was 'Lives Too Far Away'; for patients recruited by telephone it was 'Not Interested in the Study'. One factor that significantly distinguished patients who consented from patients who declined was the distance between their residence and the study site (t-test: p < .001). The most frequently reported reason for study participation was some benefit to the patient him/herself. Other reasons included helping others, being grateful to the VA, positive comments by trusted professionals, certain characteristics of the recruiter, and monetary compensation. CONCLUSIONS: The enrollment rate was low primarily because of travel considerations, but we were able to identify and highlight valuable information for planning recruitment for future similar studies

    HIV patients stable on ART retain evidence of a high CMV load but changes to Natural Killer cell phenotypes reflect both HIV and CMV

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    Background: Whilst ART corrects many effects of HIV disease, T cell populations retain features of accelerated immunological aging. Methods: Here we analyse phenotypic changes to natural killer (NK) cells in HIV patients who began ART with <200 CD4 T-cells/µl and maintained virological control for 12-17 years, compared with CMV seropositive and seronegative healthy control donors. Results: Humoral responses to CMV antigens (lysate, gB, IE-1) remain elevated in the patients (P <0.0001) despite the long duration of ART. Patient's NK cells responded poorly to K562 cells when assessed by CD107a and IFNγ, but this could not be attributed to CMV as responses were low in CMV-seronegative controls. Moreover HIV (and not CMV) increased expression of CD57 on CD56lo cells. Conclusions: Comparisons with published studies suggest that CMV accelerates age-related increases in CD57 expression but levels plateau by 60-70 years of age, so the effect of CMV disappears. In HIV patients the plateau is higher and perhaps reached sooner

    Ih Current Is Necessary to Maintain Normal Dopamine Fluctuations and Sleep Consolidation in Drosophila

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    HCN channels are becoming pharmacological targets mainly in cardiac diseases. But apart from their well-known role in heart pacemaking, these channels are widely expressed in the nervous system where they contribute to the neuron firing pattern. Consequently, abolishing Ih current might have detrimental consequences in a big repertoire of behavioral traits. Several studies in mammals have identified the Ih current as an important determinant of the firing activity of dopaminergic neurons, and recent evidences link alterations in this current to various dopamine-related disorders. We used the model organism Drosophila melanogaster to investigate how lack of Ih current affects dopamine levels and the behavioral consequences in the sleep∶activity pattern. Unlike mammals, in Drosophila there is only one gene encoding HCN channels. We generated a deficiency of the DmIh core gene region and measured, by HPLC, levels of dopamine. Our data demonstrate daily variations of dopamine in wild-type fly heads. Lack of Ih current dramatically alters dopamine pattern, but different mechanisms seem to operate during light and dark conditions. Behaviorally, DmIh mutant flies display alterations in the rest∶activity pattern, and altered circadian rhythms. Our data strongly suggest that Ih current is necessary to prevent dopamine overproduction at dark, while light input allows cycling of dopamine in an Ih current dependent manner. Moreover, lack of Ih current results in behavioral defects that are consistent with altered dopamine levels

    VKORC1 Common Variation and Bone Mineral Density in the Third National Health and Nutrition Examination Survey

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    Osteoporosis, defined by low bone mineral density (BMD), is common among postmenopausal women. The distribution of BMD varies across populations and is shaped by both environmental and genetic factors. Because the candidate gene vitamin K epoxide reductase complex subunit 1 (VKORC1) generates vitamin K quinone, a cofactor for the gamma-carboxylation of bone-related proteins such as osteocalcin, we hypothesized that VKORC1 genetic variants may be associated with BMD and osteoporosis in the general population. To test this hypothesis, we genotyped six VKORC1 SNPs in 7,159 individuals from the Third National Health and Nutrition Examination Survey (NHANES III). NHANES III is a nationally representative sample linked to health and lifestyle variables including BMD, which was measured using dual energy x-ray absorptiometry (DEXA) on four regions of the proximal femur. In adjusted models stratified by race/ethnicity and sex, SNPs rs9923231 and rs9934438 were associated with increased BMD (p = 0.039 and 0.024, respectively) while rs8050894 was associated with decreased BMD (p = 0.016) among non-Hispanic black males (n = 619). VKORC1 rs2884737 was associated with decreased BMD among Mexican-American males (n = 795; p = 0.004). We then tested for associations between VKORC1 SNPs and osteoporosis, but the results did not mirror the associations observed between VKORC1 and BMD, possibly due to small numbers of cases. This is the first report of VKORC1 common genetic variation associated with BMD, and one of the few reports available that investigate the genetics of BMD and osteoporosis in diverse populations

    Spiritual Well-Being and Depression in Patients with Heart Failure

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    BACKGROUND: In patients with chronic heart failure, depression is common and associated with poor quality of life, more frequent hospitalizations, and higher mortality. Spiritual well-being is an important, modifiable coping resource in patients with terminal cancer and is associated with less depression, but little is known about the role of spiritual well-being in patients with heart failure. OBJECTIVE: To identify the relationship between spiritual well-being and depression in patients with heart failure. DESIGN: Cross-sectional study. PARTICIPANTS: Sixty patients aged 60 years or older with New York Heart Association class II–IV heart failure. MEASUREMENTS: Spiritual well-being was measured using the total scale and 2 subscales (meaning/peace, faith) of the Functional Assessment of Chronic Illness Therapy—Spiritual Well-being scale, depression using the Geriatric Depression Scale—Short Form (GDS-SF). RESULTS: The median age of participants was 75 years. Nineteen participants (32%) had clinically significant depression (GDS-SF > 4). Greater spiritual well-being was strongly inversely correlated with depression (Spearman’s correlation −0.55, 95% confidence interval −0.70 to −0.35). In particular, greater meaning/peace was strongly associated with less depression (r = −.60, P < .0001), while faith was only modestly associated (r = −.38, P < .01). In a regression analysis accounting for gender, income, and other risk factors for depression (social support, physical symptoms, and health status), greater spiritual well-being continued to be significantly associated with less depression (P = .05). Between the 2 spiritual well-being subscales, only meaning/peace contributed significantly to this effect (P = .02) and accounted for 7% of the variance in depression. CONCLUSIONS: Among outpatients with heart failure, greater spiritual well-being, particularly meaning/peace, was strongly associated with less depression. Enhancement of patients’ sense of spiritual well-being might reduce or prevent depression and thus improve quality of life and other outcomes in this population

    Salinity and Simulated Herbivory Influence Spartina alterniflora Traits and Defense Strategy

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    Sea level rise is expected to push saline waters into previously fresher regions of estuaries, and higher salinities may expose oligohaline marshes to invertebrate herbivores typically constrained by salinity. The smooth cordgrass, Spartina alterniflora (syn. Sporobolus alterniflorus), can defend itself against herbivores in polyhaline marshes, however it is not known if S. alterniflora’s defense varies along the mesohaline to oligohaline marsh gradient in estuaries. I found that S. alterniflora from a mesohaline marsh is better defended than plants from an oligohaline marsh, supporting the optimal defense theory. Higher salinity treatments lowered carbon content, C:N, and new stem biomass production, traits associated with a tolerance strategy, suggesting that salinity may mediate the defense response of S. alterniflora. Further, simulated herbivory increased the nitrogen content and decreased C:N of S. alterniflora. This indicates that grazing may increase S. alterniflora susceptibility to future herbivory via improved forage quality. Simulated herbivory also decreased both belowground and new stem biomass production, highlighting a potential pathway in which herbivory can indirectly facilitate marsh loss, as S. alterniflora biomass is critical for vertical accretion and marsh stability under future sea level rise scenarios

    Fish-Specific Duplicated dmrt2b Contributes to a Divergent Function through Hedgehog Pathway and Maintains Left-Right Asymmetry Establishment Function

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    Gene duplication is thought to provide raw material for functional divergence and innovation. Fish-specific dmrt2b has been identified as a duplicated gene of the dmrt2a/terra in fish genomes, but its function has remained unclear. Here we reveal that Dmrt2b knockdown zebrafish embryos display a downward tail curvature and have U-shaped somites. Then, we demonstrate that Dmrt2b contributes to a divergent function in somitogenesis through Hedgehog pathway, because Dmrt2b knockdown reduces target gene expression of Hedgehog signaling, and also impairs slow muscle development and neural tube patterning through Hedgehog signaling. Moreover, the Dmrt2b morphants display defects in heart and visceral organ asymmetry, and, some lateral-plate mesoderm (LPM) markers expressed in left side are randomized. Together, these data indicate that fish-specific duplicated dmrt2b contributes to a divergent function in somitogenesis through Hedgehog pathway and maintains the common function for left-right asymmetry establishment
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