979 research outputs found

    Intensive Blood Pressure Treatment Reduced Stroke Risk in Patients With Albuminuria in the SPRINT Trial

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    Background and Purpose- Albuminuria is associated with stroke risk among individuals with diabetes. However, the association of albuminuria with incident stroke among nondiabetic patients is less clear. Methods- We performed a post hoc analysis of the SPRINT (Systolic Blood Pressure Intervention Trial), which examined the effect of higher versus lower intensity blood pressure management on mortality in 8913 participants without diabetes. We fit unadjusted and adjusted Cox proportional hazards models to estimate the association of baseline albuminuria (urinary albumin-to-creatinine ratio ≥30 mg/g versus<30 mg/g) with stroke risk. We also assessed effect modification according to treatment arms. Results- Mean age was 68±9 years, 35% were female, and 30% were black. Median follow-up was 3.2 years, and 19% patients had baseline albuminuria. Incident stroke occurred in 129 individuals during follow-up. Albuminuria was associated with increased stroke risk (unadjusted hazard ratio, 2.24; 95% CI, 1.55-3.23; adjusted hazard ratio 1.73; 95% CI, 1.17-2.56). The association of albuminuria with incident stroke differed according to the randomized treatment arm (P interaction=0.03). In the intensive treatment arm, the association of albuminuria and stroke was nonsignificant (unadjusted hazard ratio, 1.25; 95% CI, 0.69-2.28), whereas, in the standard treatment arm, it was significant (unadjusted hazard ratio, 3.44; 95% CI, 2.11-5.61). Conclusions- In a post hoc analysis of SPRINT, baseline albuminuria (versus not) was associated with a higher risk of incident stroke, but this relationship appeared to be restricted to those in the standard treatment arm. Further studies are required to conclusively determine if reduction of albuminuria in itself is beneficial in reducing stroke risk. Clinical Trial Registration- URL: https://www.clinicaltrials.gov. Unique identifier: NCT01206062.info:eu-repo/semantics/publishedVersio

    A structurally distinct TGF-β mimic from an intestinal helminth parasite potently induces regulatory T cells

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    Helminth parasites defy immune exclusion through sophisticated evasion mechanisms, including activation of host immunosuppressive regulatory T (Treg) cells. The mouse parasite Heligmosomoides polygyrus can expand the host Treg population by secreting products that activate TGF-β signalling, but the identity of the active molecule is unknown. Here we identify an H. polygyrus TGF-β mimic (Hp-TGM) that replicates the biological and functional properties of TGF-β, including binding to mammalian TGF-β receptors and inducing mouse and human Foxp3+ Treg cells. Hp-TGM has no homology with mammalian TGF-β or other members of the TGF-β family, but is a member of the complement control protein superfamily. Thus, our data indicate that through convergent evolution, the parasite has acquired a protein with cytokine-like function that is able to exploit an endogenous pathway of immunoregulation in the host

    Plasmodium vivax circumsporozoite genotypes: a limited variation or new subspecies with major biological consequences?

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    <p>Abstract</p> <p>Background</p> <p><it>Plasmodium vivax </it>circumsporozoite variants have been identified in several geographical areas. The real implication of the genetic variation in this region of the <it>P. vivax </it>genome has been questioned for a long time. Although previous studies have observed significant association between VK210 and the Duffy blood group, we present here that evidences of this variation are limited to the CSP central portion.</p> <p>Methods</p> <p>The phylogenetic analyses were accomplished starting from the amplification of conserved domains of <it>18 SSU RNAr </it>and <it>Cyt B</it>. The antibodies responses against the CSP peptides, MSP-1, AMA-1 and DBP were detected by ELISA, in plasma samples of individuals infected with two <it>P. vivax CS </it>genotypes: VK210 and <it>P. vivax</it>-like.</p> <p>Results</p> <p>These analyses of the two markers demonstrate high similarity among the <it>P. vivax CS </it>genotypes and surprisingly showed diversity equal to zero between VK210 and <it>P. vivax</it>-like, positioning these <it>CS </it>genotypes in the same clade. A high frequency IgG antibody against the N- and C-terminal regions of the <it>P. vivax </it>CSP was found as compared to the immune response to the R- and V- repetitive regions (<it>p </it>= 0.0005, Fisher's Exact test). This difference was more pronounced when the <it>P. vivax</it>-like variant was present in the infection (<it>p </it>= 0.003, Fisher's Exact test). A high frequency of antibody response against MSP-1 and AMA-1 peptides was observed for all <it>P. vivax CS </it>genotypes in comparison to the same frequency for DBP.</p> <p>Conclusions</p> <p>This results target that the differences among the <it>P. vivax CS </it>variants are restrict to the central repeated region of the protein, mostly nucleotide variation with important serological consequences.</p

    Combining remote sensing and household level data for regional scale analysis of land cover change in the Brazilian Amazon

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    Land cover change in the Brazilian Amazon depends on the spatial variability of political, socioeconomic and biophysical factors, as well as on the land use history and its actors. A regional scale analysis was made in Rondônia State to identify possible differences in land cover change connected to spatial policies of land occupation, size and year of establishment of properties, accessibility measures and soil fertility. The analysis was made based on remote sensing data and household level data gathered with a questionnaire. Both types of analyses indicate that the highest level of total deforestation is found inside agrarian projects, especially in those established more than 20 years ago. Even though deforestation rates are similar inside and outside official settlements, inside agrarian projects forest depletion can exceed 50% at the property level within 10–14 years after establishment. The data indicate that both small-scale and medium to large-scale farmers contribute to deforestation processes in Rondônia State encouraged by spatial policies of land occupation, which provide better accessibility to forest fringes where soil fertility and forest resources are important determinants of location choic

    Polymorphisms in the α4 Integrin of Neotropical Primates: Insights for Binding of Natural Ligands and HIV-1 gp120 to the Human α4β7

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    The α4 integrin subunit associates with β7 and β1 and plays important roles in immune function and cell trafficking. The gut-homing receptor α4β7 has been recently described as a new receptor for HIV. Here, we describe polymorphisms of ITGA4 gene in New World primates (NWP), and tested their impact on the binding to monoclonal antibodies, natural ligands (MAdCAM and VCAM), and several gp120 HIV-1 envelope proteins. Genomic DNA of NWP specimens comprising all genera of the group had their exons 5 and 6 (encoding the region of binding to the ligands studied) analyzed. The polymorphisms found were introduced into an ITGA4 cDNA clone encoding the human α4 subunit. Mutant α4 proteins were co-expressed with β7 and were tested for binding of mAbs, MAdCAM, VCAM and gp120 of HIV-1, which was compared to the wild-type (human) α4. Mutant α4 proteins harboring the K201E/I/N substitution had reduced binding of all ligands tested, including HIV-1 gp120 envelopes. The mAbs found with reduced biding included one from which a clinically-approved drug for the treatment of neurological disorders has been derived. α4 polymorphisms in other primate species may influence outcomes in the development and treatment of infectious and autoimmune diseases in humans and in non-human primates

    Transient Receptor Potential Ion Channels Control Thermoregulatory Behaviour in Reptiles

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    Biological functions are governed by thermodynamics, and animals regulate their body temperature to optimise cellular performance and to avoid harmful extremes. The capacity to sense environmental and internal temperatures is a prerequisite for the evolution of thermoregulation. However, the mechanisms that enable ectothermic vertebrates to sense heat remain unknown. The recently discovered thermal characteristics of transient receptor potential ion channels (TRP) render these proteins suitable to act as temperature sensors. Here we test the hypothesis that TRPs are present in reptiles and function to control thermoregulatory behaviour. We show that the hot-sensing TRPV1 is expressed in a crocodile (Crocodylus porosus), an agamid (Amphibolurus muricatus) and a scincid (Pseudemoia entrecasteauxii) lizard, as well as in the quail and zebrafinch (Coturnix chinensis and Poephila guttata). The TRPV1 genes from all reptiles form a unique clade that is delineated from the mammalian and the ancestral Xenopus sequences by an insertion of two amino acids. TRPV1 and the cool-sensing TRPM8 are expressed in liver, muscle (transversospinalis complex), and heart tissues of the crocodile, and have the potential to act as internal thermometer and as external temperatures sensors. Inhibition of TRPV1 and TRPM8 in C. porosus abolishes the typically reptilian shuttling behaviour between cooling and heating environments, and leads to significantly altered body temperature patterns. Our results provide the proximate mechanism of thermal selection in terrestrial ectotherms, which heralds a fundamental change in interpretation, because TRPs provide the mechanism for a tissue-specific input into the animals' thermoregulatory response
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