957 research outputs found

    Examining HIV and Tuberculosis Using a Decision Support Systems Computer Simulation Model: The Case of the Russian Federation

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    The aim of this paper is to describe the development and use of a computer simulation model that can be used as a Decision Support System (DSS) to tackle the critical public health issues of the chronic diseases, HIV and HIV related Tuberculosis in the Russian Federation. The model was developed to enable health officials and decision makers to determine the impact of policies to control the chronic diseases spread in an area of Russia. This area, like many others in Russia and elsewhere, have recently witnessed an explosion of HIV infections and a worrying spread of the Multi Drug Resistant form of Tuberculosis (MDRTB). The conclusions drawn is that a high population coverage with Highly Active Anti Retroviral Treatment (HAART) (75% or higher), allied with high MDRTB cure rates, reduces cumulative deaths by 60%, with limited impact below this level. The contributions that this research offers are the development of a simulation model that can be applied as a DSS by public health officials and managers in order to inform policy making. By doing so, ways of best controlling the spread of HIV and MDRTB and reduce the mortality rate from these serious public health threats is provided

    The Faber-Jackson relation for early-type galaxies: Dependence on the magnitude range

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    We take a sample of early-type galaxies from the Sloan Digital Sky Survey (SDSS-DR7, \sim 90 000 galaxies) spanning a range of approximately 7 magmag in both gg and rr filters and analyse the behaviour of the Faber-Jackson relation parameters as functions of the magnitude range. We calculate the parameters in two ways: i) We consider the faintest (brightest) galaxies in each sample and we progressively increase the width of the magnitude interval by inclusion of the brighter (fainter) galaxies (increasing-magnitude-intervals), and ii) we consider narrow-magnitude intervals of the same width (ΔM=1.0\Delta M = 1.0 magmag) over the whole magnitude range available (narrow-magnitude-intervals). Our main results are that: i) in both increasing and narrow-magnitude-intervals the Faber-Jackson relation parameters change systematically, ii) non-parametric tests show that the fluctuations in the values of the slope of the Faber-Jackson relation are not products of chance variations. We conclude that the values of the Faber-Jackson relation parameters depend on the width of the magnitude range and the luminosity of galaxies within the magnitude range. This dependence is caused, to a great extent by the selection effects and because the geometrical shape of the distribution of galaxies on the Mlog(σ0)M - \log (\sigma_{0}) plane depends on luminosity. We therefore emphasize that if the luminosity of galaxies or the width of the magnitude range or both are not taken into consideration when comparing the structural relations of galaxy samples for different wavelengths, environments, redshifts and luminosities, any differences found may be misinterpreted.Comment: 15 pages, 5 figures. A&A. Accepte

    Detection of Wuchereria bancrofti L3 Larvae in Mosquitoes: A Reverse Transcriptase PCR Assay Evaluating Infection and Infectivity

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    Lymphatic filariasis is a disabling and disfiguring disease caused by a parasite that is transmitted by a mosquito. The life cycle of the parasite requires two hosts: the mosquito vector and the human host. Part of the developmental life cycle of the parasite occurs in the mosquito and the other part in the human host. The parasite develops through four stages in the mosquito, only the last of which is infectious to humans. The third larval stage (L3) is the infective stage that initiates human infections when infective mosquitoes bite humans. There is currently a global program attempting to eliminate this disease by administering drugs to affected communities with the goal of interrupting transmission of the parasite. The new diagnostic tool described in this paper uses molecular techniques to specifically detect the infective stage of the parasite in mosquitoes. Many mosquitoes can be tested at one time to assess the risk of ongoing transmission of filariasis in communities. In addition, this new L3-detection assay can simultaneously detect whether the mosquitoes contain ‘any-stage’ of the parasite. This provides information on infection rates in humans in the community. Both pieces of information can be used in assessing the progress of disease elimination efforts

    A Reverse Transcriptase-PCR Assay for Detecting Filarial Infective Larvae in Mosquitoes

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    Background: Existing molecular assays for filarial parasite DNA in mosquitoes cannot distinguish between infected mosquitoes that contain any stage of the parasite and infective mosquitoes that harbor third stage larvae (L3) capable of establishing new infections in humans. We now report development of a molecular L3-detection assay for Brugia malayi in vectors based on RT-PCR detection of an L3-activated gene transcript. Methodology/Principal Findings: Candidate genes identified by bioinformatics analysis of EST datasets across the B. malayilife cycle were initially screened by PCR using cDNA libraries as templates. Stage-specificity was confirmed using RNA isolated from infected mosquitoes. Mosquitoes were collected daily for 14 days after feeding on microfilaremic cat blood. RT-PCR was performed with primer sets that were specific for individual candidate genes. Many promising candidates with strong expression in the L3 stage were excluded because of low-level transcription in less mature larvae. One transcript (TC8100, which encodes a particular form of collagen) was only detected in mosquitoes that contained L3 larvae. This assay detects a single L3 in a pool of 25 mosquitoes. Conclusions/Significance: This L3-activated gene transcript, combined with a control transcript (tph-1, accession # U80971) that is constitutively expressed by all vector-stage filarial larvae, can be used to detect filarial infectivity in pools of mosquito vectors. This general approach (detection of stage-specific gene transcripts from eukaryotic pathogens) may also be useful for detecting infective stages of other vector-borne parasites

    A critical appraisal of molecular xenomonitoring as a tool for assessing progress toward elimination of lymphatic filariasis

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    We used molecular xenomonitoring (MX, detection of filarial DNA in mosquitoes) to evaluate the impact of mass drug administration (MDA) in sentinel locations in Egypt with high (11.5%) and low (4.1%) baseline microfilaria prevalence rates. Blood-fed Culex pipiens were pooled by household and tested for Wuchereria bancrofti DNA by PCR. There was no significant relationship between the infection status of household residents and parasite DNA status of mosquitoes from the same houses. After 5 MDA rounds, parasite DNA rates in mosquitoes in high- and low-prevalence areas were reduced by 93.8% and 100% to 0.19% (95% CI: 0.076–0.382%) and 0% (95% CI: 0–0.045%), respectively. These changes were consistent with decreases in microfilaria prevalence rates in these sites; they provide insight regarding the minimal mosquito DNA rates necessary for sustained transmission of filariasis in Egypt. We conclude that MX is a powerful tool for monitoring the impact of MDA on filariasis endemicity and transmission

    A real-time PCR-based assay for detection of Wuchereria bancrofti DNA in blood and mosquitoes

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    We developed and evaluated real-time polymerase chain reaction (PCR) assays for detecting Wuchereria bancrofti DNA in human blood and in mosquitoes. An assay based on detection of the W. bancrofti “LDR” repeat DNA sequence was more sensitive than an assay for Wolbachia 16S rDNA. The LDR-based assay was sensitive for detecting microfilarial DNA on dried membrane filters or on filter paper. We also compared real-time PCR with conventional PCR (C-PCR) for detecting W. bancrofti DNA in mosquito samples collected in endemic areas in Egypt and Papua New Guinea. Although the two methods had comparable sensitivity for detecting filarial DNA in reference samples, real-time PCR was more sensitive than C-PCR in practice with field samples. Other advantages of real-time PCR include its high-throughput capacity and decreased risk of cross-contamination between test samples. We believe that real-time PCR has great potential as a tool for monitoring progress in large-scale filariasis elimination programs

    Comparison of coronal discoloration induced by White MTA and CEM Cement

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    Coronal discoloration of endodontically treated teeth is a challenge in clinical dentistry. This study aimed to compare coronal discoloration induced by White Mineral Trioxide Aggregate and Calcium-enriched mixture cement. Fifty single-rooted, unrestored premolar teeth extracted for orthodontic reasons were selected. After access cavity preparation, all the root canals were instrumented with MTWO rotary files up to #40.6%. The specimens were randomly assigned to two experimental groups, White Mineral Trioxide Aggregate and Calcium-enriched mixture cement groups (n = 20), and two control groups (n = 5). In the White Mineral Trioxide Aggregate and Calcium-enriched mixture cement groups, the material was condensed via the access cavity 3 mm below the cementoenamel junction to a thickness of 3 mm. Tooth color was assessed using computer analysis of digital images. Tooth color measurements were recorded at eight time intervals: before material placement (but after tooth preparation), at 24 h, 48 h, one week, two weeks, four weeks, eight weeks, and sixteen weeks after material placement. Data were analyzed using t-test, ANOVA, repeated measure ANOVA, and Tukey HSD tests. The significance level was set at 5% for all the tests. Cervical discoloration of teeth in both experimental groups significantly increased over time (p < 0.05). However, samples in the White Mineral Trioxide Aggregate group showed more discoloration in cervical regions than Calcium-enriched mixture cement specimens after two, four, eight, and sixteen weeks (p < 0.05). Applying both White Mineral Trioxide Aggregate and Calcium-enriched mixture cement induced coronal discoloration; however, White Mineral Trioxide Aggregate samples exhibited greater cervical discoloration than Calcium-enriched mixture cement specimens after two, four, eight, and sixteen weeks
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