Enteral tranexamic acid attenuates vasopressor resistance and changes in α1-adrenergic receptor expression in hemorrhagic shock.

BACKGROUND: Irreversible hemorrhagic shock is characterized by hyporesponsiveness to vasopressor and fluid therapy. Little is known, however, about the mechanisms that contribute to this phenomenon. Previous studies have shown that decreased intestinal perfusion in hemorrhagic shock leads to proteolytically mediated increases in gut permeability, with subsequent egress of vasoactive substances systemically. Maintenance of blood pressure is achieved in part by α1 receptor modulation, which may be affected by vasoactive factors; we thus hypothesized that decreases in hemodynamic stability and vasopressor response in shock can be prevented by enteral protease inhibition. METHODS: Rats were exposed to experimental hemorrhagic shock (35 mm Hg mean arterial blood pressure for 2 hours, followed by reperfusion for 2 hours) and challenged with phenylephrine (2 µg/kg) at discrete intervals to measure vasopressor responsiveness. A second group of animals received enteral injections with the protease inhibitor tranexamic acid (TXA) (127 mM) along the small intestine and cecum 1 hour after induction of hemorrhagic shock. RESULTS: Blood pressure response (duration and amplitude) to phenylephrine after reperfusion was significantly attenuated in animals subjected to hemorrhagic shock compared with baseline and control nonshocked animals and was restored to near baseline by enteral TXA. Arteries from shocked animals also displayed decreased α1 receptor density with restoration to baseline after enteral TXA treatment. In vitro, rat shock plasma decreased α1 receptor density in smooth muscle cells, which was also abrogated by enteral TXA treatment. CONCLUSION: Results from this study demonstrate that experimental hemorrhagic shock leads to decreased response to the α1-selective agonist phenylephrine and decreased α1 receptor density via circulating shock factors. These changes are mitigated by enteral TXA with correspondingly improved hemodynamics. Proteolytic inhibition in the lumen of the small intestine improves hemodynamics in hemorrhagic shock, possibly by restoring α1 adrenergic functionality necessary to maintain systemic blood pressure and perfusion.

Multiple metabolic alterations exist in mutant PI3K cancers, but only glucose is essential as a nutrient source.

Targeting tumour metabolism is becoming a major new area of pharmaceutical endeavour. Consequently, a systematic search to define whether there are specific energy source dependencies in tumours, and how these might be dictated by upstream driving genetic mutations, is required. The PI3K-AKT-mTOR signalling pathway has a seminal role in regulating diverse cellular processes including cell proliferation and survival, but has also been associated with metabolic dysregulation. In this study, we sought to define how mutations within PI3KCA may affect the metabolic dependency of a cancer cell, using precisely engineered isogenic cell lines. Studies revealed gene expression signatures in PIK3CA mutant cells indicative of a consistent up-regulation of glycolysis. Interestingly, the genes up- and down-regulated varied between isogenic models suggesting that the primary node of regulation is not the same between models. Additional gene expression changes were also observed, suggesting that metabolic pathways other than glycolysis, such as glutaminolysis, were also affected. Nutrient dependency studies revealed that growth of PIK3CA mutant cells is highly dependent on glucose, whereas glutamine dependency is independent of PIK3CA status. In addition, the glucose dependency exhibited by PIK3CA mutant cells could not be overridden by supplementation with other nutrients. This specific dependence on glucose for growth was further illustrated by studies evaluating the effects of targeted disruption of the glycolytic pathway using siRNA and was also found to be present across a wider panel of cancer cell lines harbouring endogenous PIK3CA mutations. In conclusion, we have found that PIK3CA mutations lead to a shift towards a highly glycolytic phenotype, and that despite suggestions that cancer cells are adept at utilising alternative nutrient sources, PIK3CA mutant cells are not able to compensate for glucose withdrawal. Understanding the metabolic dependencies of PIK3CA mutant cancers will provide critical information for the design of effective therapies and tumour visualisation strategies.

Genetic risk factors for thrombosis in systemic lupus erythematosus.

OBJECTIVE: Thrombosis is a serious complication of systemic lupus erythematosus (SLE). We investigated whether genetic variants implicated in thrombosis pathways are associated with thrombosis among 2 ethnically diverse SLE cohorts. METHODS: Our discovery cohort consisted of 1698 patients with SLE enrolled in the University of California, San Francisco, Lupus Genetics Project and our replication cohort included 1361 patients with SLE enrolled in the PROFILE cohort. Patients fulfilled American College of Rheumatology SLE criteria, and data relevant to thrombosis were available. Thirty-three single nucleotide polymorphisms (SNP) previously shown to be associated with risk of deep venous thrombosis in the general population or implicated in thrombosis pathways were genotyped and tested for association with thrombosis in bivariate allelic analyses. SNP with p < 0.1 in the bivariate analyses were further tested in multivariable logistic regression models adjusted for age, sex, disease duration, antiphospholipid antibody status, smoking, nephritis, and medications. RESULTS: In the discovery cohort, 23% of patients with SLE experienced a thrombotic event. SNP in the following genes demonstrated association with thrombosis risk overall in the discovery or replication cohorts and were assessed using metaanalytic methods: factor V Leiden (FVL) rs6025 (OR 1.85, p = 0.02) and methylenetetrahydrofolate reductase (MTHFR) rs1801133 (OR 0.75, p = 0.04) in whites, and fibrinogen gamma (FGG) rs2066865 (OR 1.91, p = 0.01) in Hispanic Americans. SNP in these genes showed association with venous thrombosis risk in whites: MTHFR rs1801131 (OR 1.51, p = 0.01), MTHFR rs1801133 (OR 0.70, p = 0.04), FVL rs6025 (OR 2.69, p = 0.002), and FGG rs2066865 (OR 1.49, p = 0.02) in whites. A SNP in FGG rs2066865 (OR 2.19, p = 0.003) demonstrated association with arterial thrombosis risk in Hispanics. CONCLUSION: Our results implicate specific genetic risk factors for thrombosis in patients with SLE and suggest that genetic risk for thrombosis differs across ethnic groups.

On the vapour trail of an atmospheric imprint in insects.

Terrestrial arthropods, at constant risk from desiccation, are highly sensitive to atmospheric temperature and humidity. A physiological marker of these abiotic conditions could highlight phenotypic adaptations, indicate niche partitioning, and predict responses to climate change for a group representing three-quarters of the Earth's animal species. We show that the (18)O composition of insect haemolymph is such a measure, providing a dynamic and quantitatively predictable signal for respiratory gas exchange and inputs from atmospheric humidity. Using American cockroaches (Periplaneta americana) under defined experimental conditions, we show that insects respiring at low humidity demonstrate the expected enrichment in the (18)O composition of haemolymph because of evaporation. At high humidity, however, diffusional influx of atmospheric water vapour into the animal forces haemolymph to become depleted in (18)O. Additionally, using cockroaches sampled from natural habitats, we show that the haemolymph (18)O signature is transferred to the organic material of the insect's exoskeleton. Insect cuticle, therefore, exhibits the mean atmospheric conditions surrounding the animals prior to moulting. This discovery will help to define the climatic tolerances of species and their habitat preferences, and offers a means of quantifying the balance between niche partitioning and 'neutral' processes in shaping complex tropical forest communities.

Carriers of rare missense variants in IFIH1 are protected from psoriasis.

Testing of ∼25,000 putative functional single-nucleotide polymorphisms (SNPs) across the human genome in a genetic association study has identified three psoriasis genes, IL12B, IL23R, and IL13. We now report evidence for the association of psoriasis risk with missense SNPs in the interferon induced with helicase C domain 1 gene (IFIH1). The rare alleles of two independent SNPs were associated with decreased risk of psoriasis--rs35667974 (Ile923Val): odds ratio (OR) for minor allele carriers is 0.43, P=2.36 × 10(-5) (2,098 cases vs. 1,748 controls); and rs10930046 (His460Arg): OR for minor allele carriers is 0.51, P=6.47 × 10(-4) (2,098 cases vs. 1,744 controls). Compared to noncarriers, carriers of the 923Val and/or 460Arg variants were protected from psoriasis (OR=0.46, P=5.56 × 10(-8)). To our knowledge, these results suggest that IFIH1 is a previously unreported psoriasis gene.

Association of a single-nucleotide polymorphism in CD40 with the rate of joint destruction in rheumatoid arthritis.

OBJECTIVE: The severity of joint destruction in rheumatoid arthritis (RA) is highly variable from patient to patient and is influenced by genetic factors. Genome-wide association studies have enormously boosted the field of the genetics of RA susceptibility, but risk loci for RA severity remain poorly defined. A recent meta-analysis of genome-wide association studies identified 6 genetic regions for susceptibility to autoantibody-positive RA: CD40, KIF5A/PIP4K2C, CDK6, CCL21, PRKCQ, and MMEL1/TNFRSF14. The purpose of this study was to investigate whether these newly described genetic regions are associated with the rate of joint destruction. METHODS: RA patients enrolled in the Leiden Early Arthritis Clinic were studied (n=563). Yearly radiographs were scored using the Sharp/van der Heijde method (median followup 5 years; maximum followup 9 years). The rate of joint destruction between genotype groups was compared using a linear mixed model, correcting for age, sex, and treatment strategies. A total of 393 anti-citrullinated protein antibody (ACPA)-positive RA patients from the North American Rheumatoid Arthritis Consortium (NARAC) who had radiographic data available were used for the replication study. RESULTS: The TT and CC/CG genotypes of 2 single-nucleotide polymorphisms, rs4810485 (CD40) and rs42041 (CDK6), respectively, were associated with a higher rate of joint destruction in ACPA-positive RA patients (P=0.003 and P=0.012, respectively), with rs4810485 being significant after Bonferroni correction for multiple testing. The association of the CD40 minor allele with the rate of radiographic progression was replicated in the NARAC cohort (P=0.021). CONCLUSION: A polymorphism in the CD40 locus is associated with the rate of joint destruction in patients with ACPA-positive RA. Our findings provide one of the first non-HLA-related genetic severity factors that has been replicated.

Common variants at CD40 and other loci confer risk of rheumatoid arthritis.

To identify rheumatoid arthritis risk loci in European populations, we conducted a meta-analysis of two published genome-wide association (GWA) studies totaling 3,393 cases and 12,462 controls. We genotyped 31 top-ranked SNPs not previously associated with rheumatoid arthritis in an independent replication of 3,929 autoantibody-positive rheumatoid arthritis cases and 5,807 matched controls from eight separate collections. We identified a common variant at the CD40 gene locus (rs4810485, P = 0.0032 replication, P = 8.2 x 10(-9) overall, OR = 0.87). Along with other associations near TRAF1 (refs. 2,3) and TNFAIP3 (refs. 4,5), this implies a central role for the CD40 signaling pathway in rheumatoid arthritis pathogenesis. We also identified association at the CCL21 gene locus (rs2812378, P = 0.00097 replication, P = 2.8 x 10(-7) overall), a gene involved in lymphocyte trafficking. Finally, we identified evidence of association at four additional gene loci: MMEL1-TNFRSF14 (rs3890745, P = 0.0035 replication, P = 1.1 x 10(-7) overall), CDK6 (rs42041, P = 0.010 replication, P = 4.0 x 10(-6) overall), PRKCQ (rs4750316, P = 0.0078 replication, P = 4.4 x 10(-6) overall), and KIF5A-PIP4K2C (rs1678542, P = 0.0026 replication, P = 8.8 x 10(-8) overall).

The 5q31 variants associated with psoriasis and Crohn's disease are distinct.

Predisposition to psoriasis is known to be affected by genetic variation in HLA-C, IL12B and IL23R, but other genetic risk factors also exist. We recently reported three psoriasis-associated single nucleotide polymorphisms (SNPs) in the 5q31 locus, a region of high linkage disequilibrium laden with inflammatory pathway genes. The aim of this study was to assess whether other variants in the 5q31 region are causal to these SNPs or make independent contributions to psoriasis risk by genotyping a comprehensive set of tagging SNPs in a 725 kb region bounded by IL3 and IL4 and testing for disease association. Ninety SNPs, capturing 86.4% of the genetic diversity, were tested in one case-control sample set (467 cases/460 controls) and significant markers (P(allelic) < 0.05) (n = 9) were then tested in two other sample sets (981 cases/925 controls). All nine SNPs were significant in a meta-analysis of the combined sample sets. Pair-wise conditional association tests showed rs1800925, an intergenic SNP located just upstream of IL13 (Mantel-Haenszel P(combined) = 1.5 x 10(-4), OR = 0.77 [0.67-0.88]), could account for observed significant association of all but one other SNP, rs11568506 in SLC22A4 [Mantel-Haenszel P(combined) = 0.043, OR = 0.68 (0.47-0.99)]. Haplotype analysis of these two SNPs showed increased significance for the two common haplotypes (rs11568506-rs1800925: GC, P(combined) = 5.67 x 10(-6), OR = 1.37; GT, P(combined) = 6.01 x 10(-5), OR = 0.75; global haplotype P = 8.93 x 10(-5)). Several 5q31-region SNPs strongly associated with Crohn's disease (CD) in the recent WTCCC study were not significant in the psoriasis sample sets tested here. These results identify the most significant 5q31 risk variants for psoriasis and suggest that distinct 5q31 variants contribute to CD and psoriasis risk.

PTPN22 genetic variation: evidence for multiple variants associated with rheumatoid arthritis.

The minor allele of the R620W missense single-nucleotide polymorphism (SNP) (rs2476601) in the hematopoietic-specific protein tyrosine phosphatase gene, PTPN22, has been associated with multiple autoimmune diseases, including rheumatoid arthritis (RA). These genetic data, combined with biochemical evidence that this SNP affects PTPN22 function, suggest that this phosphatase is a key regulator of autoimmunity. To determine whether other genetic variants in PTPN22 contribute to the development of RA, we sequenced the coding regions of this gene in 48 white North American patients with RA and identified 15 previously unreported SNPs, including 2 coding SNPs in the catalytic domain. We then genotyped 37 SNPs in or near PTPN22 in 475 patients with RA and 475 individually matched controls (sample set 1) and selected a subset of markers for replication in an additional 661 patients with RA and 1,322 individually matched controls (sample set 2). Analyses of these results predict 10 common (frequency >1%) PTPN22 haplotypes in white North Americans. The sole haplotype found to carry the previously identified W620 risk allele was strongly associated with disease in both sample sets, whereas another haplotype, identical at all other SNPs but carrying the R620 allele, showed no association. R620W, however, does not fully explain the association between PTPN22 and RA, since significant differences between cases and controls persisted in both sample sets after the haplotype data were stratified by R620W. Additional analyses identified two SNPs on a single common haplotype that are associated with RA independent of R620W, suggesting that R620W and at least one additional variant in the PTPN22 gene region influence RA susceptibility.

A missense single-nucleotide polymorphism in a gene encoding a protein tyrosine phosphatase (PTPN22) is associated with rheumatoid arthritis.

Rheumatoid arthritis (RA) is the most common systemic autoimmune disease, affecting approximately 1% of the adult population worldwide, with an estimated heritability of 60%. To identify genes involved in RA susceptibility, we investigated the association between putative functional single-nucleotide polymorphisms (SNPs) and RA among white individuals by use of a case-control study design; a second sample was tested for replication. Here we report the association of RA susceptibility with the minor allele of a missense SNP in PTPN22 (discovery-study allelic P=6.6 x 10(-4); replication-study allelic P=5.6 x 10(-8)), which encodes a hematopoietic-specific protein tyrosine phosphatase also known as "Lyp." We show that the risk allele, which is present in approximately 17% of white individuals from the general population and in approximately 28% of white individuals with RA, disrupts the P1 proline-rich motif that is important for interaction with Csk, potentially altering these proteins' normal function as negative regulators of T-cell activation. The minor allele of this SNP recently was implicated in type 1 diabetes, suggesting that the variant phosphatase may increase overall reactivity of the immune system and may heighten an individual carrier's risk for autoimmune disease.

Miocardite pós-parotidite: relato de caso / Post-parotitis myocarditis: case report

Em novembro de 1993, M.G., uma menina de 6 anos e 11 meses de idade, foi internada no Hospital Infantil Joana de Gusmäo (Florianópolis,SC,Brasil) com miocardite pós-parotidite e insuficiência cardíaca congestiva. Três dias após a internaçäo foi evidenciado, no ecocardiograma, um trombo no ápice do ventrículo esquerdo, o qual, apesar do tratamento correto, embolizou para as artérias ilíacas e para uma pequena artéria mesentérica. A parotidite epidêmica (caxumba) é muito comum, sendo endêmica no mundo. Complicaçöes säo raras, e a miocardite, uma delas, é mais comum do que diagnosticada, devido a suas manifestaçöes pobres e benignas, geralmente anormalidades do ritmo e da conduçäo do coraçäo. Esse caso impressionou pelo raro evento subseqüente, ou seja, a formaçäo de um trombo mural durante uma miocardite aguda.

Estudo ecologico do baixo peso ao nascer na Grande Florianopolis / Ecological study of the low birth weight in Florianopolis Region

Por apresentarem uma intima relacao com a morbi-mortalidade perinatal, os recem-nascidos de baixo peso (RNBP-gr) sao de interesse constante da pediatria neonatal. Devido a sua associacao com nivel socio-economico e saude da populacao, o baixo peso ao nascer (BP) e considerado um dos principais indicadores de saude da humanidade. Este estudo pretende determinar a prevalencia de RNBP, por cidade e maternidade da Grande Florianopolis; delineando o comportamento das gestantes com relacao a utilizacao dos servicos existentes na regiao. Desta forma, pretende-se dar subsidios para a implantacao de um sistema regionalizado de saude perinatal, atendendo adequadamente toda a regiao da Grande Florianopolis.

Sindrome de Brachmann-De Lange: relatos de casos / Brachmann-De Lang syndrome: cases report

Este trabalho relata o caso de duas criancas nascidas em junho de 1993 no Hospital Dr. Homero de Miranda Gomes, em Sao Jose (SC) com estigmas clinicas da Sindrome de Brachmann- De Lange. Serao discutidos aspectos etiopatogenicos e a variabilidade clinica da sindrome, fazendo uma revisao nas descricoes bibliograficas.