977 resultados para surface protection
Resumo:
Ulcerative colitis, an inflammatory bowel disease, is believed to result from a breakdown of dominant tolerance mechanisms that normally control intestinal immunity. Although CD4+ T lymphocyte subpopulations and expression of MHC class II molecules have been shown to play a role in the pathogenesis of the disease, the nature of the responsible mechanisms remains unclear. In this paper we describe a novel mouse model for inflammatory bowel disease, radiation-induced colitis, that occurs with complete penetrance 6-8 wk postinduction. A combination of high dose gamma-irradiation and lack of MHC class II expression on cells of hemopoietic origin results in development of colitis in C57BL/6 mice. Because of its versatility (due to susceptibility of mice of the widely genetically manipulated C57BL/6 background), high reproducibility, and 100% penetrance, radiation-induced colitis will be a useful mouse model for colitis and a significant tool to study dominant immunological tolerance mechanisms. Moreover, our data imply that tolerization to enteric Ags requires MHC class II mediated presentation by APC of hemopoietic origin.
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A total of 190 research documents were identified in line with the criteria agreed between the researchers and the CAAB, and are included in the audit. The key findings from the analysis of the audit are as follows:Â Â - Research identified in the audit has tended to focus on child protection and the child protection system generally, as well as sexual abuse. This research has primarily been undertaken by clinicians and academics, and spans across sectors. Â - Over half, (110 or 58%) of the research falls under the heading of policy/practice reviews/analysis. This is further reflected in the fact that the research most commonly focused on operating procedures, followed by practice issues and the policy framework, both in studies with a single focus and those with multiple foci. Â - The most common type of publication was peer reviewed article (74 or 39%), with commissioned research accounting for just 7% (13). This is in line with the findings that 68% (128) of commissioning/publishing bodies and 74% (139) of research bodies were in the academic sector. Â - The research published and/or commissioned by the statutory sector follows the pattern found in the audit generally, with the most common type of study being policy/practice review/analysis (27 or 48%) and the most common focus being operating procedures (22 or 39%). Â - Information sources rarely incorporated primary research with children, with only 14 studies (8%) citing direct contact with children and young people. Information on children was more commonly gathered from case files, professionals and family members. Â - The topics covered in the identified research were very wide-ranging but closely related to the primary subject area (type of abuse) and the sector in which the research was located. Â One conclusion stated that: There is a shortage of child protection-focused research on the factors that cause and perpetuate child abuse, such as homelessness, addiction, parental mental illness and domestic violence. The need for material on these areas is demonstrated by the nature and scale of reports to the child protection system and the removal of some children from their families into out of home care as a result of the above mentioned adversities.This resource was contributed by The National Documentation Centre on Drug Use.
Resumo:
An effective vaccine against schistosomiasis mansoni would be a valuable control tool and the high levels of protection elicited in rodents and primates by radiation-attenuated cercariae provide proof of principle. A major obstacle to vaccine development is the difficulty of identifying the antigens that mediate protection, not least because of the size of the genome at 280Mb DNA encoding 14,000 to 20,000 genes. The technologies collectively called proteomics, including 2D electrophoresis, liquid chromatography and mass spectrometry, now permit any protein to be identified provided there is extensive DNA data, and preferably a genome sequence. Applied to soluble (cytosolic) proteins from schistosomes, proteomics reveals the great similarity in composition between life cycle stages, with several WHO vaccine candidates amongst the most abundant constituents. The proteomic approach has been successfully applied to identify the secretions used by cercaria to penetrate host skin, the gut secretions of adult worms and the proteins exposed on the tegument surface. Soluble proteins can also be separated by 2D electrophoresis before western blotting to identify the full range of antigenic targets present in a parasite preparation. The next step is to discover which target proteins represent the weak points in the worm's defences.
Resumo:
Information is very scarce on the prevalence of hepatitis-B virus (HBV) infection among blood donors and patients with human immunodeficiency virus (HIV) infection in Nigeria. Hepatitis-B surface antigen (HBsAg) ELISA was used to determined the prevalence of HBsAg among 175 blood donors (aged 20-40 years) and 490 HIV-infected patients (aged 17-60 years) in Jos, Nigeria. Twenty-five (14.3%) of the blood donors and 127 (25.9%) of the HIV-infected individuals were HBsAg seropositive, indicating a higher HBV infection among HIV-infected persons than among healthy blood donors. A slightly higher HBsAg seroprevalence was recorded in the males (14.6%) than females (12.9%) of the blood donors. Among the HIV-infected patients, the males had considerably higher HBsAg seroprevalence than the females (31.8 vs 22.1%) with the highest prevalence of HBsAg occurring in the 51-60 years age group (44%), followed by those of 31-40 years (28.2%). Results confirmed the high endemicity of HBV infection in Jos, Nigeria and the significantly greater prevalence of HBV infection among HIV -infected patients than among blood donors.
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Species distribution models (SDMs) studies suggest that, without control measures, the distribution of many alien invasive plant species (AIS) will increase under climate and land-use changes. Due to limited resources and large areas colonised by invaders, management and monitoring resources must be prioritised. Choices depend on the conservation value of the invaded areas and can be guided by SDM predictions. Here, we use a hierarchical SDM framework, complemented by connectivity analysis of AIS distributions, to evaluate current and future conflicts between AIS and high conservation value areas. We illustrate the framework with three Australian wattle (Acacia) species and patterns of conservation value in Northern Portugal. Results show that protected areas will likely suffer higher pressure from all three Acacia species under future climatic conditions. Due to this higher predicted conflict in protected areas, management might be prioritised for Acacia dealbata and Acacia melanoxylon. Connectivity of AIS suitable areas inside protected areas is currently lower than across the full study area, but this would change under future environmental conditions. Coupled SDM and connectivity analysis can support resource prioritisation for anticipation and monitoring of AIS impacts. However, further tests of this framework over a wide range of regions and organisms are still required before wide application.
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To increase blood safety Brazil introduced screening for anti-HBc among blood donors in 1993. There was a decrease in the hepatitis B virus (HBV) transmission, but this measure identified a great number of HBsAg-negative, anti-HBc-positive donors. Surveillance policy determines that contacts of HBV carriers should be screened to HBV markers, but there is no recommendation about how to guide contacts of HBsAg-negative, anti-HBc-positive donors. Aiming to evaluate whether the contacts of this group are at greater risk for HBV infection, a cross-sectional study was performed to compare prevalence of HBV infection between contacts of HBsAg-positive blood donors (group I) and contacts of HBsAg-negative, anti-HBc-positive donors (group II). Contacts were submitted to a questionnaire and blood tests for HBV markers. In group I (n = 143), 53 (37.1%) were anti-HBc-positive and 11 (7.7%) were HBsAg-positive. In group II (n = 111), there were 9 and 0.9%, respectively. HBV exposure was associated with group I, sexual activity, blood transfusion, being one of the donor's parents, and living for more than ten years with the donor. Regarding the families as sample units, it was more common to find at least one member with HBV markers (p < 0.05) among the families of group I compared to group II. Contacts of HBsAg-negative, anti-HBc-positive individuals presented a much lower risk of having already been exposed to HBV and there is no need to screen them for HBV in low to moderate prevalence populations.
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The posters highlight some signs and symptoms that indicate that something is having a negative effect on your mental health and promote the website www.mindingyourhead.info� as a source of help for anyone finding it difficult coping with their feelings.
Resumo:
Indirect enzyme-linked immunosorbent assays (ELISAs) based on recombinant major surface protein 5 (rMSP5) and initial body (IB) antigens from a Brazilian isolate of Anaplasma marginale were developed to detect antibodies against this rickettsia in cattle. Both tests showed the same sensitivity (98.2%) and specificities (100% for rMSP5 and 93.8% for IB ELISA) which did not differ statistically. No cross-reactions were detected with Babesia bigemina antibodies, but 5 (rMSP5 ELISA) to 15% (IB ELISA) of cross-reactions were detected with B. bovis antibodies. However, such difference was not statistically significant. Prevalences of seropositive crossbred beef cattle raised extensively in Miranda county, state of Mato Grosso do Sul, Brazil, were 78.1% by rMSP5 ELISA and 79.7% by IB ELISA. In the analysis of sera from dairy calves naturally-infected with A. marginale, the dynamics of antibody production was very similar between both tests, with maternal antibodies reaching the lowest levels at 15-30 days, followed by an increase in the mean optical densities in both ELISAs, suggesting the development of active immunity against A. marginale. Results showed that all calves were seropositive by one-year old, characterizing a situation of enzootic stability. The similar performances of the ELISAs suggest that both tests can be used in epidemiological surveys for detection of antibodies to A. marginale in cattle.
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The prevention of hepatitis B by vaccination is one of the most efficient tools to avoid the transmission of the virus. This study evaluated the immunogenicity of the national vaccine Butang® in children born in Campo Mourão City, state of Paraná, Brazil, aged 7 to 12 months, by determining the anti-HBsAg antibodies levels after completion of the National Immunization Program Protocol for hepatitis B. All 70 children evaluated by the MEIA method (immune-enzymatic micro particles) showed seroconversion to the Butang® vaccine. Nine children (12.9%) presented a low response, with anti-HBs titers between 11 and 100 mUI/ml; 39 children (55.7%) showed a good response to the vaccine, with titers between 101 and 1000 mUI/ml; and 22 children (31.4%) showed antibodies titers higher than 1000 mUI/ml. The mean titer of the anti-HBs antibody titers was 1408.1 ± 2870.26 mUI/ml (15.7 to 19560.0 mUI/ml). The levels of antibodies produced by the prematurely-born children were not statistically different from those found in the newborns. Fifty-five children were also evaluated through the ELFA method (ELISA with a final detection in fluorescence), which presented similar results. The results obtained in our study corroborated the effectiveness of the national vaccine Butang® in newborn children of Campo Mourão City, Paraná, even if they were premature.
Resumo:
An effective schistosome vaccine is a desirable control tool but progress towards that goal has been slow. Protective immunity has been difficult to demonstrate in humans, particularly children, so no routes to a vaccine have emerged from that source. The concept of concomitant immunity appeared to offer a paradigm for a vaccine operating against incoming larvae in the skin but did not yield the expected dividends. The mining of crude parasite extracts, the use of monoclonal antibodies and protein selection based on immunogenicity produced a panel of vaccine candidates, mostly of cytoplasmic origin. However, none of these performed well in independent rodent trials, but glutathione-S-transferease from Schistosoma haematobium is currently undergoing clinical trials as an anti-fecundity vaccine. The sequencing of the S. mansoni transcriptome and genome and the development of proteomic and microarray technologies has dramatically improved the possibilities for identifying novel vaccine candidates, particularly proteins secreted from or exposed at the surface of schistosomula and adult worms. These discoveries are leading to a new round of protein expression and protection experiments that will enable us to evaluate systematically all the major targets available for immune intervention. Only then will we know if schistosomes have an Achilles' heel.
Resumo:
The tegument surface of the adult schistosome, bounded by a normal plasma membrane overlain by a secreted membranocalyx, holds the key to understanding how schistosomes evade host immune responses. Recent advances in mass spectrometry (MS), and the sequencing of the Schistosoma mansoni transcriptome/genome, have facilitated schistosome proteomics. We detached the tegument from the worm body and enriched its surface membranes by differential extraction, before subjecting the preparation to liquid chromatography-based proteomics to identify its constituents. The most exposed proteins on live worms were labelled with impearmeant biotinylation reagents, and we also developed methods to isolate the membranocalyx for analysis. We identified transporters for sugars, amino acids, inorganic ions and water, which confirm the importance of the tegument plasma membrane in nutrient acquisition and solute balance. Enzymes, including phosphohydrolases, esterases and carbonic anhydrase were located with their catalytic domains external to the plasma membrane, while five tetraspanins, annexin and dysferlin were implicated in membrane architecture. In contrast, few parasite proteins could be assigned to the membranocalyx but mouse immune response proteins, including three immunoglobulins and two complement factors, were detected, plus host membrane proteins such as CD44, integrin and a complement regulatory protein, testifying to the acquisitive properties of the secreted bilayer.