800 research outputs found
Inflammation and endothelial function: Direct vascular effects of human C-reactive protein on nitric oxide bioavailability
Background - Circulating concentrations of the sensitive inflammatory marker C-reactive protein (CRP) predict future cardiovascular events, and CRP is elevated during sepsis and inflammation, when vascular reactivity may be modulated. We therefore investigated the direct effect of CRP on vascular reactivity. Methods and Results - The effects of isolated, pure human CRP on vasoreactivity and protein expression were studied in vascular rings and cells in vitro, and effects on blood pressure were studied in rats in vivo. The temporal relationship between changes in CRP concentration and brachial flow-mediated dilation was also studied in humans after vaccination with Salmonella typhi capsular polysaccharide, a model of inflammatory endothelial dysfunction. In contrast to some previous reports, highly purified and well-characterized human CRP specifically induced hyporeactivity to phenylephrine in rings of human internal mammary artery and rat aorta that was mediated through physiological antagonism by nitric oxide (NO). CRP did not alter endothelial NO synthase protein expression but increased protein expression of GTP cyclohydrolase-1, the rate-limiting enzyme in the synthesis of tetrahydrobiopterin, the NO synthase cofactor. In the vaccine model of inflammatory endothelial dysfunction in humans, increased CRP concentration coincided with the resolution rather than the development of endothelial dysfunction, consistent with the vitro findings; however, administration of human CRP to rats had no effect on blood pressure. Conclusions - Pure human CRP has specific, direct effects on vascular function in vitro via increased NO production; however, further clarification of the effect, if any, of CRP on vascular reactivity in humans in vivo will require clinical studies using specific inhibitors of CRP. © 2005 American Heart Association, Inc
Triorchidism at orchidopexy: a case report
This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
An approximate model for cancellous bone screw fixation
This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ 2013 Taylor & Francis.This paper presents a finite element (FE) model to identify parameters that affect the performance of an improved cancellous bone screw fixation technique, and hence potentially improve fracture treatment. In cancellous bone of low apparent density, it can be difficult to achieve adequate screw fixation and hence provide stable fracture fixation that enables bone healing. Data from predictive FE models indicate that cements can have a significant potential to improve screw holding power in cancellous bone. These FE models are used to demonstrate the key parameters that determine pull-out strength in a variety of screw, bone and cement set-ups, and to compare the effectiveness of different configurations. The paper concludes that significant advantages, up to an order of magnitude, in screw pull-out strength in cancellous bone might be gained by the appropriate use of a currently approved calcium phosphate cement
Cost-effectiveness of HBV and HCV screening strategies:a systematic review of existing modelling techniques
Introduction:
Studies evaluating the cost-effectiveness of screening for Hepatitis B Virus (HBV) and Hepatitis C Virus (HCV) are generally heterogeneous in terms of risk groups, settings, screening intervention, outcomes and the economic modelling framework. It is therefore difficult to compare cost-effectiveness results between studies. This systematic review aims to summarise and critically assess existing economic models for HBV and HCV in order to identify the main methodological differences in modelling approaches.
Methods:
A structured search strategy was developed and a systematic review carried out. A critical assessment of the decision-analytic models was carried out according to the guidelines and framework developed for assessment of decision-analytic models in Health Technology Assessment of health care interventions.
Results:
The overall approach to analysing the cost-effectiveness of screening strategies was found to be broadly consistent for HBV and HCV. However, modelling parameters and related structure differed between models, producing different results. More recent publications performed better against a performance matrix, evaluating model components and methodology.
Conclusion:
When assessing screening strategies for HBV and HCV infection, the focus should be on more recent studies, which applied the latest treatment regimes, test methods and had better and more complete data on which to base their models. In addition to parameter selection and associated assumptions, careful consideration of dynamic versus static modelling is recommended. Future research may want to focus on these methodological issues. In addition, the ability to evaluate screening strategies for multiple infectious diseases, (HCV and HIV at the same time) might prove important for decision makers
Characteristics of transposable element exonization within human and mouse
Insertion of transposed elements within mammalian genes is thought to be an
important contributor to mammalian evolution and speciation. Insertion of
transposed elements into introns can lead to their activation as alternatively
spliced cassette exons, an event called exonization. Elucidation of the
evolutionary constraints that have shaped fixation of transposed elements
within human and mouse protein coding genes and subsequent exonization is
important for understanding of how the exonization process has affected
transcriptome and proteome complexities. Here we show that exonization of
transposed elements is biased towards the beginning of the coding sequence in
both human and mouse genes. Analysis of single nucleotide polymorphisms (SNPs)
revealed that exonization of transposed elements can be population-specific,
implying that exonizations may enhance divergence and lead to speciation. SNP
density analysis revealed differences between Alu and other transposed
elements. Finally, we identified cases of primate-specific Alu elements that
depend on RNA editing for their exonization. These results shed light on TE
fixation and the exonization process within human and mouse genes.Comment: 11 pages, 4 figure
Identification of Giardia lamblia DHHC Proteins and the Role of Protein S-palmitoylation in the Encystation Process
Protein S-palmitoylation, a hydrophobic post-translational modification, is performed by protein acyltransferases that have a common DHHC Cys-rich domain (DHHC proteins), and provides a regulatory switch for protein membrane association. In this work, we analyzed the presence of DHHC proteins in the protozoa parasite Giardia lamblia and the function of the reversible S-palmitoylation of proteins during parasite differentiation into cyst. Two specific events were observed: encysting cells displayed a larger amount of palmitoylated proteins, and parasites treated with palmitoylation inhibitors produced a reduced number of mature cysts. With bioinformatics tools, we found nine DHHC proteins, potential protein acyltransferases, in the Giardia proteome. These proteins displayed a conserved structure when compared to different organisms and are distributed in different monophyletic clades. Although all Giardia DHHC proteins were found to be present in trophozoites and encysting cells, these proteins showed a different intracellular localization in trophozoites and seemed to be differently involved in the encystation process when they were overexpressed. dhhc transgenic parasites showed a different pattern of cyst wall protein expression and yielded different amounts of mature cysts when they were induced to encyst. Our findings disclosed some important issues regarding the role of DHHC proteins and palmitoylation during Giardia encystation.Fil: Merino, Maria Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Zamponi, Nahuel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Vranych, Cecilia Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Touz, Maria Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; ArgentinaFil: Ropolo, Andrea Silvana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra. Universidad Nacional de Córdoba. Instituto de Investigación Médica Mercedes y Martín Ferreyra; Argentin
From evidence to best practice in the management of fractures of the distal radius in adults: working towards a research agenda
BACKGROUND: Fracture of the distal radius is a common clinical problem, particularly in older white women with osteoporosis. We report our work towards evidence-based and patient-centred care for adults with these injuries. METHODS: We developed a systematic programme of research that built on our systematic review of the evidence of effectiveness of treatment interventions for these fractures. We devised schemata showing 'typical' care pathways and identified over 100 patient management questions. These depicted the more important decisions taken when progressing along each care pathway. We compiled a comprehensive document summarising the evidence available for each decision point from our reviews of randomised trials of treatment interventions. Using these documents, we undertook a formal and structured consultation process involving key players, including a patient representative, to obtain their views on the available evidence and to establish a research agenda. The resulting feedback was then processed and interpreted, using systematic methods. RESULTS: Some evidence from 114 randomised trials was available for 31 of the 117 patient management questions. However, there was sufficient evidence to base some conclusions of effectiveness for particular interventions in only five of these. Though only 60% of those approached responded, the responses received from the consultation group were often comprehensive and provided important insights into treatment practice and policy. There was a clear acceptance of the aims of the project and, aside from some suggestions for the more explicit inclusion of secondary prevention and management of complications, of the care pathways scheme. Though some respondents stressed that randomised trials were not always appropriate, there was no direct overall criticism of the evidence document and underlying processes. We were able to identify important core themes that underpin management decisions and research from the feedback of the consultation exercise. CONCLUSIONS: Overall, this project is an important advance towards evidence-based and patient-centred management of adults with distal radial fractures. It exposes the serious deficiency in the available evidence but also provides a template for further action. As well as being a valuable basis for viewing and informing current practice, the insights gained from this project should inform a future research agenda
Rectal Transmission of Transmitted/Founder HIV-1 Is Efficiently Prevented by Topical 1% Tenofovir in BLT Humanized Mice
Rectal microbicides are being developed to prevent new HIV infections in both men and women. We focused our in vivo preclinical efficacy study on rectally-applied tenofovir. BLT humanized mice (n = 43) were rectally inoculated with either the primary isolate HIV-1(JRCSF) or the MSM-derived transmitted/founder (T/F) virus HIV-1(THRO) within 30 minutes following treatment with topical 1% tenofovir or vehicle. Under our experimental conditions, in the absence of drug treatment we observed 50% and 60% rectal transmission by HIV-1(JRCSF) and HIV-1(THRO), respectively. Topical tenofovir reduced rectal transmission to 8% (1/12; log rank p = 0.03) for HIV-1(JRCSF) and 0% (0/6; log rank p = 0.02) for HIV-1(THRO). This is the first demonstration that any human T/F HIV-1 rectally infects humanized mice and that transmission of the T/F virus can be efficiently blocked by rectally applied 1% tenofovir. These results obtained in BLT mice, along with recent ex vivo, Phase 1 trial and non-human primate reports, provide a critically important step forward in the development of tenofovir-based rectal microbicides
Left atrial giant thrombus infected by Escherichia Coli. Case report
This is an Open Access article distributed under the terms of the Creative Commons Attribution Licens
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