511 research outputs found

    Brassica genomics: a complement to, and early beneficiary of, the Arabidopsis sequence.

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    Those studying the genus Brassica will be among the early beneficiaries of the now-completed Arabidopsis sequence. The remarkable morphological diversity of Brassica species and their relatives offers valuable opportunities to advance our knowledge of plant growth and development, and our understanding of rapid phenotypic evolution

    FGF dependent regulation of Zfhx1b gene expression promotes the formation of definitive neural stem cells in the mouse anterior neurectoderm

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    <p>Abstract</p> <p>Background</p> <p>Mouse definitive neural stem cells (NSCs) are derived from a population of LIF-responsive primitive neural stem cells (pNSCs) within the neurectoderm, yet details on the early signaling and transcriptional mechanisms that control this lineage transition are lacking. Here we tested whether FGF and Wnt signaling pathways can regulate <it>Zfhx1b </it>expression to control early neural stem cell development.</p> <p>Results</p> <p>By microinjecting FGF8b into the pro-amniotic cavity <it>ex vivo </it>at 7.0 days post-coitum (dpc) and culturing whole embryos, we demonstrate that neurectoderm-specific gene expression (for example, <it>Sox2</it>, <it>Nestin</it>, <it>Zfhx1b</it>) is increased, whereas Wnt3a represses neurectoderm gene expression. To determine whether FGF signaling also mediates the lineage transition from a pNSC to a NSC, 7.0-dpc embryos were microinjected with either FGF8b or inhibitors of the FGF receptor-MAP kinase signaling pathway <it>ex vivo</it>, cultured as whole embryos to approximately 8.5 dpc and assayed for clonal NSC colony formation. We show that pre-activation of FGF signaling in the anterior neurectoderm causes an increase in the number of colony forming NSCs derived later from the anterior neural plate, whereas inhibition of FGF signaling significantly reduces the number of NSC colonies. Interestingly, inhibition of FGF signaling causes the persistence of LIF-responsive pNSCs within the anterior neural plate and over-expression of <it>Zfhx1b </it>in these cells is sufficient to rescue the transition from a LIF-responsive pNSC to an FGF-responsive NSC.</p> <p>Conclusion</p> <p>Our data suggest that definitive NSC fate specification in the mouse neurectoderm is facilitated by FGF activation of <it>Zfhx1b</it>.</p

    Phase diagram of Eu magnetic ordering in Sn-flux-grown Eu(Fe1x_{1-x}Cox_{x})2_{2}As2_{2} single crystals

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    The magnetic ground state of the Eu2+^{2+} moments in a series of Eu(Fe1x_{1-x}Cox_{x})2_{2}As2_{2} single crystals grown from the Sn flux has been investigated in detail by neutron diffraction measurements. Combined with the results from the macroscopic properties (resistivity, magnetic susceptibility and specific heat) measurements, a phase diagram describing how the Eu magnetic order evolves with Co doping in Eu(Fe1x_{1-x}Cox_{x})2_{2}As2_{2} is established. The ground-state magnetic structure of the Eu2+^{2+} spins is found to develop from the A-type antiferromagnetic (AFM) order in the parent compound, via the A-type canted AFM structure with some net ferromagnetic (FM) moment component along the crystallographic c\mathit{c} direction at intermediate Co doping levels, finally to the pure FM order at relatively high Co doping levels. The ordering temperature of Eu declines linearly at first, reaches the minimum value of 16.5(2) K around x\mathit{x} = 0.100(4), and then reverses upwards with further Co doping. The doping-induced modification of the indirect Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction between the Eu2+^{2+} moments, which is mediated by the conduction d\mathit{d} electrons on the (Fe,Co)As layers, as well as the change of the strength of the direct interaction between the Eu2+^{2+} and Fe2+^{2+} moments, might be responsible for the change of the magnetic ground state and the ordering temperature of the Eu sublattice. In addition, for Eu(Fe1x_{1-x}Cox_{x})2_{2}As2_{2} single crystals with 0.10 \leqslant x\mathit{x} \leqslant 0.18, strong ferromagnetism from the Eu sublattice is well developed in the superconducting state, where a spontaneous vortex state is expected to account for the compromise between the two competing phenomena.Comment: 10 pages, 9 figure

    Leukotriene A4 Hydrolase Genotype and HIV Infection Influence Intracerebral Inflammation and Survival From Tuberculous Meningitis.

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    BACKGROUND: Tuberculous meningitis (TBM) is the most devastating form of tuberculosis, yet very little is known about the pathophysiology. We hypothesized that the genotype of leukotriene A4 hydrolase (encoded by LTA4H), which determines inflammatory eicosanoid expression, influences intracerebral inflammation, and predicts survival from TBM. METHODS: We characterized the pretreatment clinical and intracerebral inflammatory phenotype and 9-month survival of 764 adults with TBM. All were genotyped for single-nucleotide polymorphism rs17525495, and inflammatory phenotype was defined by cerebrospinal fluid (CSF) leukocyte and cytokine concentrations. RESULTS: LTA4H genotype predicted survival of human immunodeficiency virus (HIV)-uninfected patients, with TT-genotype patients significantly more likely to survive TBM than CC-genotype patients, according to Cox regression analysis (univariate P = .040 and multivariable P = .037). HIV-uninfected, TT-genotype patients had high CSF proinflammatory cytokine concentrations, with intermediate and lower concentrations in those with CT and CC genotypes. Increased CSF cytokine concentrations correlated with more-severe disease, but patients with low CSF leukocytes and cytokine concentrations were more likely to die from TBM. HIV infection independently predicted death due to TBM (hazard ratio, 3.94; 95% confidence interval, 2.79-5.56) and was associated with globally increased CSF cytokine concentrations, independent of LTA4H genotype. CONCLUSIONS: LTA4H genotype and HIV infection influence pretreatment inflammatory phenotype and survival from TBM. LTA4H genotype may predict adjunctive corticosteroid responsiveness in HIV-uninfected individuals

    Lack of knowledge about sexually transmitted infections among women in North rural Vietnam

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    <p>Abstract</p> <p>Background</p> <p>The serious long-term complications of sexually transmitted infections (STI) in women and newborns are well-documented. Particularly, STI imply considerable social consequences for women. Low STI knowledge has been shown to be associated with unsafe sex. In Vietnam, misconceptions regarding STI exist, and rural women delay seeking care for STI. The aim of the study was to investigate knowledge of STI among women aged 15 to 49 years in a rural district of Vietnam and to evaluate possible associations between socioeconomic factors and STI knowledge.</p> <p>Methods</p> <p>A cross-sectional population-based study using face-to-face interviews was carried out between March and May 2006 in a demographic surveillance site in rural Vietnam. In total, 1805 women aged 15–49 years were randomly selected to participate in the study. The interviews were based on a structured questionnaire including questions on sociodemographic characteristics of the women and their knowledge about STI. Each correct answer was scored 1, incorrect or do not know answer was scored 0. Multivariate analyses were applied to examine associations between socio-economic conditions and STI knowledge. Intra-cluster correlation was calculated to examine similarities of STI knowledge within clusters.</p> <p>Results</p> <p>Of the 1,805 respondents, 78% (73% married vs. 93% unmarried, p < 0.001) did not know any symptoms of STI, 50% could not identify any cause of STI, 59% (54% married vs. 76% unmarried, p < 0.001) did not know that STI can be prevented. Only 31% of the respondents (36% married vs. 14% unmarried, p < 0.001) answered that condom use could protect against STI, and 56% considered partner treatment necessary. Of 40 possible correct answers, the mean knowledge score was 6.5 (range 0–26, median 6). Young, unmarried women and women who lived in the highlands or mountainous areas demonstrated very low levels of STI knowledge (regression coefficients -1.3 and -2.5, respectively, p < 0.001). Experience of an induced abortion was significantly associated with a higher level of knowledge.</p> <p>Conclusion</p> <p>The low levels of STI knowledge found among women of reproductive age in a rural district of Vietnam indicate an urgent need of health education interventions, of which, young and unmarried women should be specifically targeted.</p

    Health services for reproductive tract infections among female migrant workers in industrial zones in Ha Noi, Viet Nam: an in-depth assessment

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    BACKGROUND: Rural-to-urban migration involves a high proportion of females because job opportunities for female migrants have increased in urban industrial areas. Those who migrate may be healthier than those staying in the village and they may benefit from better health care services at destination, but the 'healthy' effect can be reversed at destination due to migration-related health risk factors. The study aimed to explore the need for health care services for reproductive tract infections (RTIs) among female migrants working in the Sai Dong industrial zone as well as their services utilization. METHODS: The cross sectional study employed a mixed method approach. A cohort of 300 female migrants was interviewed to collect quantitative data. Two focus groups and 20 in-depth interviews were conducted to collect qualitative data. We have used frequency and cross-tabulation techniques to analyze the quantitative data and the qualitative data was used to triangulate and to provide more in-depth information. RESULTS: The needs for health care services for RTI were high as 25% of participants had RTI syndromes. Only 21.6% of female migrants having RTI syndromes ever seek helps for health care services. Barriers preventing migrants to access services were traditional values, long working hours, lack of information, and high cost of services. Employers had limited interests in reproductive health of female migrants, and there was ineffective collaboration between the local health system and enterprises. These barriers were partly caused by lack of health promotion programs suitable for migrants. Most respondents needed more information on RTIs and preferred to receive these from their employers since they commonly work shifts--and spend most of their day time at work. CONCLUSION: While RTIs are a common health problem among female migrant workers in industrial zones, female migrants had many obstacles in accessing RTI care services. The findings from this study will help to design intervention models for RTI among this vulnerable group such as communication for behavioural impact of RTI health care, fostered collaboration between local health care services and employer enterprises, and on-site service (e.g. local or enterprise health clinics) strengthenin

    Integration of decision support systems to improve decision support performance

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    Decision support system (DSS) is a well-established research and development area. Traditional isolated, stand-alone DSS has been recently facing new challenges. In order to improve the performance of DSS to meet the challenges, research has been actively carried out to develop integrated decision support systems (IDSS). This paper reviews the current research efforts with regard to the development of IDSS. The focus of the paper is on the integration aspect for IDSS through multiple perspectives, and the technologies that support this integration. More than 100 papers and software systems are discussed. Current research efforts and the development status of IDSS are explained, compared and classified. In addition, future trends and challenges in integration are outlined. The paper concludes that by addressing integration, better support will be provided to decision makers, with the expectation of both better decisions and improved decision making processes

    Reproductive tract infections in women seeking abortion in Vietnam

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    <p>Abstract</p> <p>Background</p> <p>Women requesting abortion are at increased risk of developing RTI complications. However, RTI control in many resource-poor countries including Vietnam have been faced with logistical and methodological problems due to lack of standardized definitions of RTIs, lack of well-validated diagnostic criteria, lack of accurate laboratory tests, and lack of diagnostic equipment and skills. This article investigates the prevalence of RTIs among Vietnamese abortion-seeking women, to evaluate the available diagnostic techniques, and to assess antibiotic resistance among aetiological agents of RTI.</p> <p>Method</p> <p>The study was conducted in Phu-San hospital (PSH) from December 2003 through April 2004 among 748 abortion clients. A structured questionnaire was used to collect data on socio-economic and reproductive characteristics. Specimens were collected for laboratory analyses of chlamydia, gonorrhoea, trichomoniasis, vaginal candidiasis (VC), bacterial vaginosis (BV) and syphilis. To assess the validity of the obtained results, the study was repeated among 100 women and the duplicate samples were analysed at PSH and Copenhagen University Hospital (CUH).</p> <p>Results</p> <p>In all 54% of the women were diagnosed as having an RTI, including 3.3% with sexually transmitted infections. Endogenous infections were most prevalent (VC 34% and BV 12%) followed by chlamydia (1.3%) and trichomoniasis (0.7%). The sensitivity of culture for VC and BV was 30% and 88%, respectively, when tests in PSH were measured against tests in CUH. Antibiotic resistance was common among bacterial isolates.</p> <p>Conclusion</p> <p>RTIs are common among women seeking abortion. The presence of RTIs is associated with an increased risk of developing iatrogenic infections, routine administration of prophylactic antibiotic to all women undergoing abortion should be considered. However, the choice of routine prophylactic antibiotics should be based on relevant surveillance data of antibiotic resistance. Moreover, since the accuracy of diagnosis is doubtful and to address the problem of under-diagnosed and treated RTIs new investment in diagnostic facilities with simple performed microscopy or improved rapid tests should also be taken into consideration.</p

    A physical map of Brassica oleracea shows complexity of chromosomal changes following recursive paleopolyploidizations

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    <p>Abstract</p> <p>Background</p> <p>Evolution of the Brassica species has been recursively affected by polyploidy events, and comparison to their relative, <it>Arabidopsis thaliana</it>, provides means to explore their genomic complexity.</p> <p>Results</p> <p>A genome-wide physical map of a rapid-cycling strain of <it>B. oleracea </it>was constructed by integrating high-information-content fingerprinting (HICF) of Bacterial Artificial Chromosome (BAC) clones with hybridization to sequence-tagged probes. Using 2907 contigs of two or more BACs, we performed several lines of comparative genomic analysis. Interspecific DNA synteny is much better preserved in euchromatin than heterochromatin, showing the qualitative difference in evolution of these respective genomic domains. About 67% of contigs can be aligned to the Arabidopsis genome, with 96.5% corresponding to euchromatic regions, and 3.5% (shown to contain repetitive sequences) to pericentromeric regions. Overgo probe hybridization data showed that contigs aligned to Arabidopsis euchromatin contain ~80% of low-copy-number genes, while genes with high copy number are much more frequently associated with pericentromeric regions. We identified 39 interchromosomal breakpoints during the diversification of <it>B. oleracea </it>and <it>Arabidopsis thaliana</it>, a relatively high level of genomic change since their divergence. Comparison of the <it>B. oleracea </it>physical map with Arabidopsis and other available eudicot genomes showed appreciable 'shadowing' produced by more ancient polyploidies, resulting in a web of relatedness among contigs which increased genomic complexity.</p> <p>Conclusions</p> <p>A high-resolution genetically-anchored physical map sheds light on Brassica genome organization and advances positional cloning of specific genes, and may help to validate genome sequence assembly and alignment to chromosomes.</p> <p>All the physical mapping data is freely shared at a WebFPC site (<url>http://lulu.pgml.uga.edu/fpc/WebAGCoL/brassica/WebFPC/</url>; Temporarily password-protected: account: pgml; password: 123qwe123.</p
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