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991.
Population density, water supply, and the risk of dengue fever in Vietnam: cohort study and spatial analysis 总被引:1,自引:0,他引:1
Schmidt WP Suzuki M Thiem VD White RG Tsuzuki A Yoshida LM Yanai H Haque U Tho le H Anh DD Ariyoshi K 《PLoS medicine》2011,8(8):e1001082
Background
Aedes aegypti, the major vector of dengue viruses, often breeds in water storage containers used by households without tap water supply, and occurs in high numbers even in dense urban areas. We analysed the interaction between human population density and lack of tap water as a cause of dengue fever outbreaks with the aim of identifying geographic areas at highest risk.Methods and Findings
We conducted an individual-level cohort study in a population of 75,000 geo-referenced households in Vietnam over the course of two epidemics, on the basis of dengue hospital admissions (n = 3,013). We applied space-time scan statistics and mathematical models to confirm the findings. We identified a surprisingly narrow range of critical human population densities between around 3,000 to 7,000 people/km2 prone to dengue outbreaks. In the study area, this population density was typical of villages and some peri-urban areas. Scan statistics showed that areas with a high population density or adequate water supply did not experience severe outbreaks. The risk of dengue was higher in rural than in urban areas, largely explained by lack of piped water supply, and in human population densities more often falling within the critical range. Mathematical modeling suggests that simple assumptions regarding area-level vector/host ratios may explain the occurrence of outbreaks.Conclusions
Rural areas may contribute at least as much to the dissemination of dengue fever as cities. Improving water supply and vector control in areas with a human population density critical for dengue transmission could increase the efficiency of control efforts. Please see later in the article for the Editors'' Summary 相似文献992.
Baker S Holt KE Clements AC Karkey A Arjyal A Boni MF Dongol S Hammond N Koirala S Duy PT Nga TV Campbell JI Dolecek C Basnyat B Dougan G Farrar JJ 《Open biology》2011,1(2):110008
Typhoid is a systemic infection caused by Salmonella Typhi and Salmonella Paratyphi A, human-restricted bacteria that are transmitted faeco-orally. Salmonella Typhi and S. Paratyphi A are clonal, and their limited genetic diversity has precluded the identification of long-term transmission networks in areas with a high disease burden. To improve our understanding of typhoid transmission we have taken a novel approach, performing a longitudinal spatial case-control study for typhoid in Nepal, combining single-nucleotide polymorphism genotyping and case localization via global positioning. We show extensive clustering of typhoid occurring independent of population size and density. For the first time, we demonstrate an extensive range of genotypes existing within typhoid clusters, and even within individual households, including some resulting from clonal expansion. Furthermore, although the data provide evidence for direct human-to-human transmission, we demonstrate an overwhelming contribution of indirect transmission, potentially via contaminated water. Consistent with this, we detected S. Typhi and S. Paratyphi A in water supplies and found that typhoid was spatially associated with public water sources and low elevation. These findings have implications for typhoid-control strategies, and our innovative approach may be applied to other diseases caused by other monophyletic or emerging pathogens. 相似文献
993.
Inherited mutation of the purine salvage enzyme, hypoxanthine guanine phosphoribosyltransferase (HPRT) gives rise to Lesch–Nyhan syndrome (LNS) or Lesch–Nyhan variants (LNVs). We report three novel independent mutations in the coding region of HPRT gene: exon 3: c.141delA, p.D47fs53X; exon 5: c.400G>A, p.E134K; exon 7: c.499A>G, p.R167G from three LNS affected male patients. 相似文献
994.
Min-Pyo Hong Kiem Vu Jennifer M. Bautos Rick Tham Mantana Jamklang John P. Uhrig Angie Gelli 《Eukaryotic cell》2013,12(1):142-150
Calcium (Ca2+)-mediated signaling events in fungal pathogens such as Cryptococcus neoformans are central to physiological processes, including those that mediate stress responses and promote virulence. The Cch1-Mid1 channel (CMC) represents the only high-affinity Ca2+ channel in the plasma membrane of fungal cells; consequently, cryptococci cannot survive in low-Ca2+ environments in the absence of CMC. Previous electrophysiological characterization revealed that Cch1, the predicted channel pore, and Mid1, a binding partner of Cch1, function as a store-operated Ca2+-selective channel gated by depletion of endoplasmic reticulum (ER) Ca2+ stores. Cryptococci lacking CMC did not survive ER stress, indicating its critical role in restoring Ca2+ homeostasis. Despite the requirement for Mid1 in promoting Ca2+ influx via Cch1, identification of the role of Mid1 remains elusive. Here we show that the C-terminal tail of Mid1 is a modulatory region that impinges on Cch1 channel activity directly and mediates the trafficking of Mid1 to the plasma membrane. This region consists of the last 24 residues of Mid1, and the functional expression of Mid1 in a human embryonic cell line (HEK293) and in C. neoformans is dependent on this domain. Substitutions of arginine (R619A) or cysteine (C621A) in the modulatory region failed to target Mid1 to the plasma membrane and prevented CMC activity. Interestingly, loss of a predicted protein kinase C (PKC)-phosphorylated serine residue (S605A) had no effect on Mid1 trafficking but did alter the kinetics of Cch1 channel activity. Thus, establishment of Ca2+ homeostasis in C. neoformans is dependent on a modulatory domain of Mid1. 相似文献
995.
996.
Isabelle Lardon Göran E. Nilsson Jonathan A. W. Stecyk Trung Nghia Vu Kris Laukens Roger Dommisse Gudrun De Boeck 《Metabolomics : Official journal of the Metabolomic Society》2013,9(2):311-323
The crucian carp (Carassius carassius) can tolerate anoxia for days to months, depending on the temperature. In this study, we applied 1H-NMR-based metabolomics to polar extracts of crucian carp brain, heart, muscle and liver samples obtained from fish exposed to either control normoxic conditions, acute anoxia (24 h), chronic anoxia (1 week) or reoxygenation (for 1 week following chronic anoxia) at 5 °C. Spectra of the examined tissues revealed changes in several energy-related compounds. In particular, anoxic stress resulted in decreased concentrations of phosphocreatine (muscle, liver) and glycogen (liver) and ATP/ADP (liver, heart and muscle) and increased concentrations of lactate (brain, heart, muscle) and beta-hydroxybutyric acid (all tissues). Likewise, increased concentrations of inhibitory compounds (glycine, gamma-amino butyric acid or GABA) and decreased concentrations of excitatory metabolites (glutamate, glutamine) were confirmed in the anoxic brain extracts. Additionally, a decrease of N-acetylaspartate (NAA), an important neuronal marker, was also observed in anoxic brains. The branched-chain amino acids (BCAA) valine/isoleucine/leucine increased in all anoxic tissues. Possibly, this general tissue increase can be due to an inhibited mitochondrial function or due to protein degradation/protein synthesis inhibition. In this study, the potential and strength of the 1H-NMR is highlighted by the detection of previously unrecognized changes in metabolites. Specifically, myo-inositol substantially decreased in the heart of anoxic crucian carp and anoxic muscle tissue displayed a decreased concentration of taurine, providing novel insights into the anoxia responses of the crucian carp. 相似文献
997.
Binh Phuong Nhan Nguyen Nanjundan Ashok Kumar Joël Gaubicher Florence Duclairoir Thierry Brousse Olivier Crosnier Lionel Dubois Gérard Bidan Dominique Guyomard Bernard Lestriez 《Liver Transplantation》2013,3(10):1351-1357
Reduced graphene oxide (rGO) is used as a conductive additive for nanosilicon‐based lithium battery anodes with the high active‐mass loading typically required for industrial applications. In contrast to conventional Si electrodes that use acetylene black (AcB) as an additive, the rGO system shows pronounced improvement of electrochemical performance, irrespective of the cycling conditions. With capacity limitation, the rGO system results in improved coulombic efficiency (99.9%) and longer cycle life than conventional electrodes. Upon cycling without capacity limitation, much higher discharge capacity is maintained (2000 mAh g?1 after 100 cycles for 2.5 mg of Si cm?2). Used in conjunction with the bridging carboxymethyl cellulose binder, the crumpled and resilient rGO allows highly reversible functioning of the electrode in which the Si particles repeatedly inflate and deflate upon alloying and dealloying with lithium. 相似文献
998.
Trang T. Vu Eric A. Hill Leo A. Kucek Allan E. Konopka Alexander S. Beliaev Prof. Jennifer L. Reed 《Biotechnology journal》2013,8(5):619-630
Cyanobacteria are ideal metabolic engineering platforms for carbon-neutral biotechnology because they directly convert CO2 to a range of valuable products. In this study, we present a computational assessment of biochemical production in Synechococcus sp. PCC 7002 (Synechococcus 7002), a fast growing cyanobacterium whose genome has been sequenced, and for which genetic modification methods have been developed. We evaluated the maximum theoretical yields (mol product per mol CO2 or mol photon) of producing various chemicals under photoautotrophic and dark conditions using a genome-scale metabolic model of Synechococcus 7002. We found that the yields were lower under dark conditions, compared to photoautotrophic conditions, due to the limited amount of energy and reductant generated from glycogen. We also examined the effects of photon and CO2 limitations on chemical production under photoautotrophic conditions. In addition, using various computational methods such as minimization of metabolic adjustment (MOMA), relative metabolic change (RELATCH), and OptORF, we identified gene-knockout mutants that are predicted to improve chemical production under photoautotrophic and/or dark anoxic conditions. These computational results are useful for metabolic engineering of cyanobacteria to synthesize value-added products. 相似文献
999.
Rachel Lieberman R. Paul Wadwa Nhung Nguyen Franziska K. Bishop Christina Reinick Janet K. Snell-Bergeon David M. Maahs 《PloS one》2013,8(10)
Objective
Vitamin D deficiency is common and associated with increased cardiovascular disease (CVD) risk. Pulse wave velocity (PWV) is a marker of vascular stiffness associated with CVD. We hypothesized that Vitamin D (25 (OH) D) levels would be inversely associated with PWV in youth with and without type 1 diabetes (T1D).Study Design
Comparisons were made between adolescents with T1D (n = 211; age = 17.5±2.3 years; diabetes duration = 10.9±3.2 years; A1c = 9.1±1.7%) and non-DM controls (n = 67; age = 16.9±1.9 years). PWV was measured in the carotid-femoral segment (Sphygmocor Vx, AtCor Medical, Lisle, IL).Results
Vitamin D levels were similar in adolescents with T1D and controls (27.7±0.7 v. 26.0±1.3 ng/ml; p = 0.26). Vitamin D was significantly inversely associated with PWV after adjusting for age, sex, quarter of the year, and race-ethnicity in adolescents with T1D (beta = −0.01±0.004, p = 0.02) but not in the non-DM adolescents (beta = −0.008±0.008, p = 0.32). Vitamin D remained significantly associated with PWV after additionally adjusting for hs-CRP in adolescents with T1D (−0.01±0.004, p = 0.01). After adjusting for BMI z-score, lipids, or blood pressure, the relationship of Vitamin D with PWV was not significant.Conclusions
Vitamin D levels were inversely associated with PWV in adolescents with T1D, but not independently of BMI, lipids, or blood pressure. Our data contrast with other reports and suggest further research is indicated to determine if Vitamin D supplementation would be beneficial to lower CVD risk in adolescents with T1D with vitamin D insufficiency or deficiency. 相似文献1000.
Cristina Menni Toma Keser Massimo Mangino Jordana T. Bell Idil Erte Irena Akma?i? Frano Vu?kovi? Maja Pu?i? Bakovi? Olga Gornik Mark I. McCarthy Vlatka Zoldo? Tim D. Spector Gordan Lauc Ana M. Valdes 《PloS one》2013,8(12)