981 resultados para Detectability with ELISA


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The increase in world travel in recent years, especially to and from areas where vector-borne diseases are endemic, has resulted in a substantial rise in imported cases of those diseases. In particular, malaria is a cause of concern. In those countries at the edge of its distribution, it can be difficult to distinguish between autochthonous and imported cases. However, distinguishing between the two is important because of the different allocation of resources to combat the disease that each requires. In general, observation of the various stages of parasite development in wild-caught female mosquitoes is considered evidence of autochthonous transmission. Observation of oocysts in the mosquito mid-gut testifies that mosquitoes are susceptible to infection but conclusions cannot be reached about their ability to complete the transmission cycle. Perhaps the best indication of autochthonous transmission is microscopic observation of sporozoites in mosquito salivary glands, since this detects parasites ready to be inoculated (BELER et al., 1990). Detection of circumsporozoite protein (CSP)(BURKOT, WILLIAMS & SCHNEIDER, 1984) in dry mosquito thoraxes, by Enzyme Linked Immunosorbent Assay (ELISA) is also widely used to determine transmission, especially when large numbers of mosquitoes need to be processed. Such assays provide information about the parasite species infecting the mosquito (BURKOT & WIRTZ, 1986; WIRTZ et al., 1987; BELER et al., 1990).

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The sexes of Pseudometocha melanocephala (Perty, 1833) and of a new species of Anomophotopsis are associated based on mating pairs found in the field and also in laboratory mating trials. The previously unknown male of Pseudomethoca melanocephala (Perty, 1833) and both sexes of Anomophotopsis quinteroi Cambra, sp. nov., are described. We present the first distribution record of P. melanocephala from Argentina. Anecdotal data on their mating behavior are also discussed.

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In this paper, generalizing results in Alòs, León and Vives (2007b), we see that the dependence of jumps in the volatility under a jump-diffusion stochastic volatility model, has no effect on the short-time behaviour of the at-the-money implied volatility skew, although the corresponding Hull and White formula depends on the jumps. Towards this end, we use Malliavin calculus techniques for Lévy processes based on Løkka (2004), Petrou (2006), and Solé, Utzet and Vives (2007).

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In this paper we use Malliavin calculus techniques to obtain an expression for the short-time behavior of the at-the-money implied volatility skew for a generalization of the Bates model, where the volatility does not need to be neither a difussion, nor a Markov process as the examples in section 7 show. This expression depends on the derivative of the volatility in the sense of Malliavin calculus.

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Hypertension is a heritable and major contributor to the global burden of disease. The sum of rare and common genetic variants robustly identified so far explain only 1%-2% of the population variation in BP and hypertension. This suggests the existence of more undiscovered common variants. We conducted a genome-wide association study in 1,621 hypertensive cases and 1,699 controls and follow-up validation analyses in 19,845 cases and 16,541 controls using an extreme case-control design. We identified a locus on chromosome 16 in the 5' region of Uromodulin (UMOD; rs13333226, combined P value of 3.6×10(-11)). The minor G allele is associated with a lower risk of hypertension (OR [95%CI]: 0.87 [0.84-0.91]), reduced urinary uromodulin excretion, better renal function; and each copy of the G allele is associated with a 7.7% reduction in risk of CVD events after adjusting for age, sex, BMI, and smoking status (H.R. = 0.923, 95% CI 0.860-0.991; p = 0.027). In a subset of 13,446 individuals with estimated glomerular filtration rate (eGFR) measurements, we show that rs13333226 is independently associated with hypertension (unadjusted for eGFR: 0.89 [0.83-0.96], p = 0.004; after eGFR adjustment: 0.89 [0.83-0.96], p = 0.003). In clinical functional studies, we also consistently show the minor G allele is associated with lower urinary uromodulin excretion. The exclusive expression of uromodulin in the thick portion of the ascending limb of Henle suggests a putative role of this variant in hypertension through an effect on sodium homeostasis. The newly discovered UMOD locus for hypertension has the potential to give new insights into the role of uromodulin in BP regulation and to identify novel drugable targets for reducing cardiovascular risk.

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Introduction: Infection with Epstein-Barr Virus (EBV) and a lack invitamin D are emerging as the twomost significant environmental triggersof multiple sclerosis (MS). Sincewe and others have shown that CD8+T cells are important immune mediatorsof the inflammatory response inMS, we examined whether vitamin Ddirectly affects the CD8+ T cell response.We also explored if vitaminDmodulates the EBV-specific CD8+ Tcell response. Methods: PBMC of 10patients with early MS and 10 healthycontrols (HC) were stimulated eitherwith a pool of EBVimmunodominantpeptides or anti-CD3/anti-CD28 beads.Cytokine secretion was assessed witha Cytometric Beads Array (CBA),ELISA and intracellular cytokinestaining. To examine whether vitaminD could directly modulate CD8+ Tcell immune responses, we depletedCD4+ T cells using a negative selection.Results: We found that vitaminD-treated PBMC stimulated eitherwith the EBV peptide pool or anti-CD3/anti-CD28 beads adopted ananti-inflammatory profile: significantdecrease in IFN-and TNF secretion,contrasting with a significant increasein IL-5 and TGF-secretion. At baseline,but also after vitamin D stimulation,IL-5 was significantly less producedby stimulated CD8+ T cells ofearly MS than HC. Finally, using depletionof CD4+ T cells, we couldshow that vitaminDcan directlymodulateCD8+ T cells. Discussion: Ourdata suggest that vitaminDconfers ananti-inflammatory profile to CD8+ Tcells, without the help of CD4+ Tcells. Even if vitamin D has a significanteffect on CD8+ T cells of earlyMS patients, this "rescuing" effect isof smaller magnitude than in HC subjects.Finally, vitamin D does influencethe CD8+ T cell response toEBV in early MS patients, suggestingthat there is an interplay betweenthese two major environmental factorsof MS.

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Clin Microbiol Infect ABSTRACT: The aetiological diagnosis of community-acquired pneumonia (CAP) is challenging in children, and serological markers would be useful surrogates for epidemiological studies of pneumococcal CAP. We compared the use of anti-pneumolysin (Ply) antibody alone or with four additional pneumococcal surface proteins (PSPs) (pneumococcal histidine triad D (PhtD), pneumococcal histidine triad E (PhtE), LytB, and pneumococcal choline-binding protein A (PcpA)) as serological probes in children hospitalized with CAP. Recent pneumococcal exposure (positive blood culture for Streptococcus pneumoniae, Ply(+) blood PCR finding, and PSP seroresponse) was predefined as supporting the diagnosis of presumed pneumococcal CAP (P-CAP). Twenty-three of 75 (31%) children with CAP (mean age 33.7 months) had a Ply(+) PCR finding and/or a ≥2-fold increase of antibodies. Adding seroresponses to four PSPs identified 12 additional patients (35/75, 45%), increasing the sensitivity of the diagnosis of P-CAP from 0.44 (Ply alone) to 0.94. Convalescent anti-Ply and anti-PhtD antibody titres were significantly higher in P-CAP than in non P-CAP patients (446 vs. 169 ELISA Units (EU)/mL, p 0.031, and 189 vs. 66 EU/mL, p 0.044), confirming recent exposure. Acute anti-PcpA titres were three-fold lower (71 vs. 286 EU/mL, p <0.001) in P-CAP children. Regression analyses confirmed a low level of acute PcpA antibodies as the only independent predictor (p 0.002) of P-CAP. Novel PSPs facilitate the demonstration of recent pneumococcal exposure in CAP children. Low anti-PcpA antibody titres at admission distinguished children with P-CAP from those with CAP with a non-pneumococcal origin.

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The feasibility of no-tillage in the Cerrado (Savanna-like vegetation of Brazil) depends on the production of sufficient above-ground crop residue, which can be increased by corn-forage intercropping. This study evaluated how above-ground crop residue production and yields of soybean and late-season corn in a soybean-corn rotation were influenced by the following crops in the year before soybean: corn (Zea mays L.) intercropped with Brachiaria (Urochloa) brizantha cv. Marandu, B. decumbens cv. Basilisk, B. ruziziensis, cv. comum., Panicummaximum cv. Tanzânia, sunn hemp (Crotalaria juncea L.), pigeon pea [Cajanus cajan (L.) Millsp]; sole corn, forage sorghum [Sorghum bicolor (L.) Moench (cv. Santa Elisa)], and ruzi grass. In March 2005, corn and forage species were planted in alternate rows spaced 0.90 m apart, and sole forage species were planted in rows spaced 0.45 m apart. In October 2005, the forages were killed with glyphosate and soybean was planted. After the soybean harvest in March 2006, sole late-season corn was planted in the entire experimental area. Corn grain and stover yields were unaffected by intercropping. Above-ground crop residue was greater when corn was intercropped with Tanzania grass (10.7 Mg ha-1), Marandu (10.1 Mg ha-1), and Ruzi Grass (9.8 Mg ha-1) than when corn was not intercropped (4.0 Mg ha-1). The intercropped treatments increased the percentage of soil surface covered with crop residue. Soybean and corn grain yields were higher after sole ruzi grass and intercropped ruzi grass than after other crops. The intercropping corn with Brachiaria spp. and corn with Panicum spp. increases above-ground crop residue production and maintains nutrients in the soil without reducing late-season corn yield and the viability of no-till in the midwestern region of Brazil.

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Metaphyseal chondromatosis with hydroxyglutaric aciduria (MC-HGA) is a generalized skeletal dysplasia, accompanied by urinary excretion of D-2- hydroxyglutarate (HGA), and variable cerebral involvement. By wholeexome sequencing 2 unrelated patients with MC-HGA, we have found mutations in isocitrate dehydrogenase 1 (IDH1) at codon 132, as apparent somatic mosaicism. IDH1 is a key enzyme of the Krebs cycle, which converts isocitrate into alpha-ketoglutarate (a-KG). Mutations at IDH1 Arg132 residue have originally been identified in different tumour types (isolated gliomas, leukemias, and chondrosarcomas). These mutations trans-specify the enzyme activity resulting in HGA accumulation and a-KG depletion. This induces activation of hypoxia-inducible factor 1-alpha (HIF-1a), an important regulator of chondrocyte proliferation at the growth plate. Differently from Arg132 somatic mutations found in isolated tumours, themutation in our patientsmust have occurred very early in embryogenesis to cause a generalized dysplasia with involvement of all long bones metaphyses and mutation detectability in blood. Identical mutations have subsequently been identified in chondromas excised from patients with multiple chondromatosis (Ollier disease). Tissue distribution of themutationmay explain variable cerebral involvement and the susceptibility to develop tumours in other organs. The postulated pathophysiology ofMC-HGA points out the link between Krebs cycle, hypoxia sensing and bone growth.

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BACKGROUND: Fragile X-associated tremor/ataxia syndrome (FXTAS) is an inherited late-onset neurodegenerative disorder, characterized both by neurological and cognitive deficits. It is caused by the expansion of CGG repeats (55 to 200 repeats) in the noncoding region of the fragile X mental retardation 1 (FMR1) gene. Abnormal immunological patterns are often associated with neurodegenerative disorders and implicated in their etiology. We therefore investigated the immune status of FXTAS patients, which had not been assessed prior to this study. METHOD: Peripheral blood mononuclear cells (PBMCs) were collected from 15 asymptomatic FMR1 premutation carriers and 20 age-matched controls. Concentrations of three cytokines (IL-6, IL-8, IL-10) were measured in PBMC supernatants using ELISA assays. RESULTS: We found a significant increase in the concentration of the major anti-inflammatory cytokine IL-10 in supernatants of PBMCs derived from premutation carriers, when compared with controls (P = 0.019). This increase correlated significantly with the number of CGG repeats (P = 0.002). CONCLUSIONS: Elevated IL-10 levels were observed in all premutation carriers, before appearance of the classical neurological symptoms; therefore, IL-10 may be one of the early biomarkers of FXTAS.

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Objective: To investigate the association between common carotid artery intima-media thickness (cIMT) and exposure to secondhand smoke (SHS) in children. Methods: Data were available at baseline in the Quebec Adiposity and Lifestyle investigation in Youth (QUALITY) study, an ongoing longitudinal investigation of Caucasian children aged 8e10 years at cohort inception, who had at least one obese parent. Data on exposure to parents, siblings and friends smoking were collected in interviewer-administered child, and self-report parent questionnaires. Blood cotinine was measured with a high sensitivity ELISA. cIMTwas measured by ultrasound. The association between blood cotinine and cIMT was investigated in multivariable linear regression analyses controlling for age, body mass index, and child smoking status. Results: Mean (SD) cIMT (0.5803 (0.04602)) did not differ across age or sex. Overall 26%, 6% and 3% of children were exposed to parents, siblings and friends smoking, respectively. Cotinine ranged from 0.13 ng/ml to 7.38 ng/ml (median (IQR)¼0.18 ng/ml)). Multivariately, a 1 ng/ml increase in cotinine was associated with a 0.090 mm increase in cIMT (p¼0.034). Conclusion: In children as young as age 8e10 years, exposure to SHS relates to cIMT, a marker of pre-clinical atherosclerosis. Given the wide range of health effects of SHS, increased public health efforts are needed to reduced exposure among children in homes an private vehicles.

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BACKGROUND AND AIMS: Mannan-binding lectin (MBL) and ficolins are microbial pattern recognition molecules that activate the lectin pathway of complement. We previously reported the association of MBL deficiency with anti-Saccharomyces cerevisiae antibodies (ASCA) in patients with Crohn's disease (CD). However, ASCA are also frequently found in MBL-proficient CD patients. Here we addressed expression/function of ficolins and MBL-associated serine protease-2 (MASP-2) regarding potential association with ASCA. METHODS: ASCA titers and MBL, ficolin and MASP-2 concentrations were determined by ELISA in the serum of patients with CD, ulcerative colitis (UC), and in healthy controls. MASP-2 activity was determined by measuring complement C4b-fixation. Anti-MBL autoantibodies were detected by ELISA. RESULTS: In CD and UC patients, L-ficolin concentrations were significantly higher compared to healthy controls (p<0.001 and p=0.029). In contrast, H-ficolin concentrations were slightly reduced in CD and UC compared to healthy controls (p=0.037 for UC vs. hc). CD patients with high ASCA titers had significantly lower H-ficolin concentrations compared to ASCA-low/negative CD patients (p=0.009). However, MASP-2 activity was not different in ASCA-negative and ASCA-positive CD patients upon both, ficolin- or MBL-mediated MASP-2 activation. Finally, anti-MBL autoantibodies were not over-represented in MBL-proficient ASCA-positive CD patients. CONCLUSIONS: Our results suggest that low expression of H-ficolin may promote elevated ASCA titers in the ASCA-positive subgroup of CD patients. However, unlike MBL deficiency, we found no evidence for low expression of serum ficolins or reduced MASP-2 activity that may predispose to ASCA development.

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We have compared a multiplexed bead-based assay (BBA) with an enzyme immunoassay (EIA) and immunofluorescence assay (IFA) for the assessment of the Epstein-Barr virus (EBV) serostatus. Three hundred and ninety-three sera, classified according to IFA results as seronegative (n=100), acute infection (n=100), past infection (n=100) and indeterminate (n=93), were tested by BBA and EIA. Overall, the three methods gave similar results with a relatively high (75.2%) concordance with the consensus interpretation of the serostatus. The most significant discordances were: (i) 58 samples had uninterpretable results for BBA, in majority due to the detection of non-antigen specific antibody binding by control beads. (ii) almost half the samples positive for anti-Epstein-Barr nuclear antigen (EBNA) IgG by BBA or EIA were negative by IFA. Among the latter, only a minority had a history of immunocompromise or treatment, or detectable anti-early antigen antibody. This discrepancy probably reflects a poor sensitivity of IFA for anti-EBNA IgG detection. EIA and BBA had a similar performance and had substantial practical advantages over IFA with respect to testing for EBV serostatus.

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Purpose: Adiponectin, arterial stiffness, as well components of the renin-angiotensin system are associated with cardiovascular risk. This study was aimed to investigate whether plasma adiponectin was directly linked with pulse pressure (PP), as a marker for arterial stiffness, and the renin-angiotensin system (RAS). Methods and materials: A family-based study in subjects of African descent enriched with hypertensive patients was carried out in the Seychelles. Fasting plasma adiponectin was determined by ELISA, plasma renin activity according to the antibody-trapping principle and plasma aldosterone by radioimmunoassay. Daytime ambulatory blood pressure (BP) was measured using Diasys Integra devices. PP was calculated as the difference between systolic and diastolic BP. The association of adiponectin with PP, plasma renin activity and plasma aldosterone were analyzed using generalized estimating equations with a gaussian family link and an exchangeable correlation structure to account for familial aggregation. Results: Data from 335 subjects from 73 families (152 men, 183 women) were available. Men and women had mean (SD) age of 45.4 ± 11.1 and 47.3 ± 12.4 years, BMI of 26.3 ± 4.4 and 27.8 ± 5.1 kg/m2, daytime systolic/diastolic BP of 132.6 ± 15.4 / 86.1 ± 10.9 and 130 ± 17.6 / 83.4 ± 11.1 mmHg, and daytime PP of 46.5 ± 9.9 and 46.7 ± 10.7 mmHg, respectively. Plasma adiponectin was 4.4± 3.04 ng/ml in men and 7.39 ± 5.44 ng/ml in women (P <0.001). After adjustment for age, sex and BMI, log-transformed adiponectin was negatively associated with daytime PP (-0.009 ± 0.003, P = 0.004), plasma renin activity (-0.248 ± 0.080, P = 0.002) and plasma aldosterone (-0.004 ± 0.002, P = 0.014). Conclusion: Low adiponectin is associated with increased ambulatory PP and RAS activation in subjects of African descent. Our data are consistent with the observation that angiotensin II receptor blockers increase adiponectin in humans.

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RESUME Les maladies cardio-vasculaires représentent la cause la plus importante de mortalité et de morbidité dans les pays occidentaux. La thérapie génique offre une nouvelle approche au traitement de ces maladies. L'expression de gènes protecteurs dans le myocarde par des technologies de transfert génique peut améliorer la fonction ventriculaire lors de l'insuffisance cardiaque ou stimuler la formation de nouveaux vaisseaux dans la maladie coronarienne. Etant donné qu'une majorité des maladies cardiaques sont des maladies chroniques, l'expression durable du gène thérapeutique introduit dans le coeur est souhaitable dans de nombreux cas. Malheureusement, l'utilité des vecteurs de transfert génique les plus utilisés en thérapie génique cardiovasculaire est limitée par une performance faible (ADN plasmidique) et une courte durée d'expression (adénovirus). Récemment, des vecteurs de transfert génique dérivés des lentivirus, une sous-famille des rétrovirus, ont retenu l'attention de la communauté scientifique en raison de leur capacité à exprimer des gènes à long terme. Contrairement aux vecteurs rétroviraux traditionnels, les vecteurs lentiviraux transduisent des gènes même dans des cellules qui ne se divisent pas, ce qui est le cas des cardiomyocytes adultes. Ces vecteurs présentent un profil de biosécurité comparable à celui des vecteurs rétroviraux traditionnels. Nous avons donc décidé de tester l'utilité des vecteurs lentiviraux pour le transfert génique dans des cardiomyocytes de rat adulte in vitro et in vivo. Plusieurs versions de vecteurs lentiviraux contenant différent promoteurs ont été construites. Ces vecteurs contenant le gène marqueur EGFP (enhanced green fluorescent protein) ont été testés dans des cardiomyocytes de rat in vitro, ainsi que dans des coeurs de rat in vivo. Le but de ces expériences était de déterminer la durée de l'expression du transgène après injection intramyocardique chez le rat. Pour ce faire, nous avons développé une technique ELISA pour détecter la protéine EGFP dans des extraits de tissu cardiaque. Les résultats ont montré que la protéine EGFP était encore présente à des niveaux significatifs jusqu'à dix semaines après l'injection de vecteurs lentiviraux, alors que l'expression transgénique obtenue avec un vecteur adénoviral traditionnel a été plus limitée dans le temps. Ces résultats démontrent la capacité des vecteurs lentiviraux à exprimer des gènes d'intérêt de manière performante et stable dans le cœur de rat adulte in vivo. SUMMARY Cardiovascular diseases are the first cause of morbidity and mortality in Western countries. Gene therapy offers a new approach to these diseases. Expression of therapeutic genes in the myocardium by gene transfer technologies can improve ventricular function in heart failure and stimulate neovascularization in coronary disease. Chronic heart diseases likely require sustained expression of the therapeutic gene within the heart itself. Unfortunately, the most commonly used vectors in cardiovascular gene therapy, i.e. plasmid DNA and recombinant adenovirus vectors, are limited by poor DNA uptake and transient transgene expression, respectively. Recently, lentivirus-derived vectors have attracted much interest because of their ability to achieve long-term transgene expression. In contrast to traditional retroviral vectors, lentiviral vectors are also able to transduce non- dividing cells, while presenting a comparable biosafety profile. Adult cardiomyocytes are terminally differentiated cells that do not divide under normal conditions. For these reasons, we have decided to evaluate the efficiency of lentiviral vectors for gene-transduction of adult cardiomyocytes both in vitro and in vivo. We constructed various types of lentiviral vectors containing various promoters. Vectors encoding EGFP as a reporter gene were tested in rat cardiomyocytes in vitro and in rat hearts in vivo. The aim of the experiments involved in this thesis work was to determine the duration of the expression of the transgene after rat intramyocardial injection using a quantitative assay. Therefore, an ELISA technique was set up to measure the EGFP protein in rat heart tissue extracts. Our results showed that the EGFP protein was still present at significant levels at ten weeks after lentiviral vector injection, whereas the duration of expression with adenoviral vectors was shorter. These results demonstrate that lentiviral vectors efficiently deliver genes and achieve sustained transgene expression in adult rat cardiomyocytes in vivo.