42 research outputs found
Multi-center evaluation of the hepatitis B surface antigen (HBsAg) assay and HbsAg confirmatory assay for the family of Access immunoassay systems
BACKGROUND: Accurate detection of Hepatitis B Surface Antigen (HBsAg) is an important aid in the diagnosis of patients infected with the hepatitis B virus (HBV). A multi-center study was conducted to characterize the performance of the HBsAg assay on the family of Access immunoassay systems from Beckman Coulter.
METHODS: The Access HBsAg assay was characterized in a multi-center study and compared to the Abbott AxSYM* and PRISM* HBsAg assays. The bioMĂ©rieux VIDAS* assay was used to resolve discrepant results. Reproducibility studies (intra-assay, inter-assay and inter-lot) were performed with pooled serum samples (negative sample, close to cut off, low, medium and high positive samples). Analytical sensitivity, subtype and genotype detection were studied with various commercial panels (SFTS panel, WHO 80/549, WHO 00/588, Teragenix HBV Genotype panel). A panel of recombinant HBsAg mutant proteins was tested to investigate reactivity towards genetic mutations. Clinical sensitivity was verified with seroconversion panels and samples from subjects with known HBV infection. Analytical specificity was studied with samples from patients with potential cross-reactive infections. Clinical specificity was validated among blood donors and a hospitalized population.
RESULTS: The imprecision was < 10%. Analytical sensitivity was < or = 0.1 ng/mL (SFTS panel), 0.020 PEI Units/mL (ad panel), 0.024 PEI Units/mL (ay panel), 0.092 IU/mL with WHO 80/549 and 0.056 IU/mL with WHO 00/588. All genotype samples and HBsAg mutants were reactive with the Access HBsAg assay. Seroconversion panels tested showed no significant difference with the reference method. Sensitivity for subjects with known HBV infection was 100%. No interference with potentially cross-reactive infections was observed after confirmatory testing. Specificity was 99.96% (100% after confirmatory testing) in a blood donor population and 99.5% (100% after confirmatory testing) in a hospitalized population. Excellent separation of positive and negative populations was observed.
CONCLUSIONS: The Access HBsAg and HBsAg Confirmatory assays meet all clinical and analytical performance requirements of assays for the detection of HBsAg
Rapid Probing of Biological Surfaces with a Sparse-Matrix Peptide Library
Finding unique peptides to target specific biological surfaces is crucial to basic research and technology development, though methods based on biological arrays or large libraries limit the speed and ease with which these necessary compounds can be found. We reasoned that because biological surfaces, such as cell surfaces, mineralized tissues, and various extracellular matrices have unique molecular compositions, they present unique physicochemical signatures to the surrounding medium which could be probed by peptides with appropriately corresponding physicochemical properties. To test this hypothesis, a naĂŻve pilot library of 36 peptides, varying in their hydrophobicity and charge, was arranged in a two-dimensional matrix and screened against various biological surfaces. While the number of peptides in the matrix library was very small, we obtained âhitsâ against all biological surfaces probed. Sequence refinement of the âhitsâ led to peptides with markedly higher specificity and binding activity against screened biological surfaces. Genetic studies revealed that peptide binding to bacteria was mediated, at least in some cases, by specific cell-surface molecules, while examination of human tooth sections showed that this method can be used to derive peptides with highly specific binding to human tissue
Facteurs associĂ©s au maintien dans le poste de travail aprĂšs un Ă©pisode dâabsence : rĂ©sultats de lâĂ©tude MAPOST des mĂ©decins du travail du groupe La Poste
International audienceObjective. Identify job factors associated to return to work, especially age, among postal workers after a work absence due to health reasons. Methods. In 2015, 32 La Poste occupational physicians conducted a cross-sectional descriptive epidemiological study within 477 postmen over 49 years and 339 of postmen aged between 40 and 49 years old. The main variable of interest is how to stay in work after a sickness absence for more than 30 days. The explanatory variables are personal, medical and occupational factors. Perceived health, perceived physical constraints and relational factors were scored. Multivariate statistical analysis was done by multinomial logistic regression. Results. At the time of medical visit, half of the workers can return to work on their job, 40% can return to work with a reorganized job, 6% reclassified to another job and 4% cannot return to work. The mean total duration of the absence episode is 120 days. In multivariate analysis, the variables significantly associated with a higher risk of having a job arrangement are: age; a cause of absence workrelated; a period of sick leave of more than 90 days; a disability situation; a perceived poor health. Variables significantly associated with a higher risk of reclassification are: more than 90 days of sick leave; a cause of absence work-related; a disability situation; a poor psychosocial score; a perceived poor health. Conclusion. It is possible to identify the predictive factors of return to work after a sickness absence through simple questions and therefore to find solutions to favor the return to work on the medical as well as on the professional levels. (C) 2018 Elsevier Masson SAS. All rights reserved.Objectif. Identifier les facteurs de maintien dans lâemploi, notamment en lien avec lâĂąge, chez les postiers reprenant le travail aprĂšs un arrĂȘt de travail pour raison de santĂ©.MĂ©thodes. En 2015, 32 mĂ©decins du travail du groupe La Poste ont rĂ©alisĂ© une Ă©tude Ă©pidĂ©miologique descriptive transversale chez 477 de postiers de plus de 49 ans et 339 postiers ĂągĂ©s de 40 Ă 49 ans ayant subi un arrĂȘt de travail pour raison de santĂ©. La variable principale dâintĂ©rĂȘt est les modalitĂ©s du maintien dans le poste de travail aprĂšs un arrĂȘt de plus de 30 jours. Les variables explicatives sont les facteurs personnels, mĂ©dicaux et professionnels. La santĂ© perçue, les contraintes physiques ressenties et les facteurs relationnels ont fait lâobjet de scores. Lâanalyse statistique multivariĂ©e a Ă©tĂ© faite par une rĂ©gression logistique multinomiale.RĂ©sultats. Au moment de la visite de reprise du travail, la moitiĂ© des agents peuvent reprendre le travail sur leur poste, 40 % peuvent reprendre leur poste avec un amĂ©nagement, 6 % en Ă©tant reclassĂ©s sur un autre poste et 4 % ne peuvent pas reprendre le travail. En moyenne, la durĂ©e totale du dernier arrĂȘt de travail est de 120 jours. En analyse multivariĂ©e, les variables significativement associĂ©es Ă un risque plus Ă©levĂ© de nĂ©cessiter un amĂ©nagement de poste sont : lâĂąge ; une cause dâarrĂȘt dĂ» au travail ; une durĂ©e dâarrĂȘt de travail supĂ©rieure Ă 90 jours ; le fait dâĂȘtre en situation de handicap ; avoir une santĂ© perçue dĂ©gradĂ©e. Les variables significativement associĂ©es Ă un risque plus Ă©levĂ© de nĂ©cessitĂ© de reclassement sont : une durĂ©e dâarrĂȘt de travail supĂ©rieure Ă 90 jours ; une cause dâarrĂȘt dĂ» au travail ; le fait dâĂȘtre en situation de handicap ; avoir un mauvais score psychosocial ; avoir une santĂ© perçue dĂ©gradĂ©e.Conclusion. Il est possible dâidentifier les facteurs prĂ©dictifs dâun amĂ©nagement de poste ou dâun reclassement Ă partir de questions simples ce qui permet de rĂ©flĂ©chir Ă des solutions pour favoriser le maintien dans leur poste de travail sur le plan mĂ©dical comme sur le plan professionnel
Exposure of adults to extremely low frequency magnetic field in France: results of the EXPERS study
Assessing the exposure of adults to magnetic field is a central point in the context of epidemiological studies. The EXPERS study is the first study at national scale in Europe with measurements of personal exposure to extremely low frequency magnetic fields, involving 1046âFrench adults with 24âh personal measurements. The proportion of adults with a 24âh AM of â„â1â”T was 2.1% for all adults and 0.3% for adults for which no alarm clock was identified, as this requirement of the measurement protocol was sometimes not respected. The alarm clocks were the main variable linked to the adultsâ exposure measurements. The vicinity of the home to a high voltage power line increased the magnetic field exposure. However, only 1.7% of the adults were living close to a 63 to 400âkV overhead line, and only one of them had a personal exposure â„â1âÎŒT with an AM of 1.1âÎŒT. The exposure of adults was also correlated with some characteristics of the home and its environment, and some durations of activities, such as the duration of work and the duration in rail transport. The distribution of adultsâ personal exposure was significantly different from the distribution of exposure during sleep, and from the distribution of exposure assessed from measurements during sleep and work. This highlights the complexity of the exposure assessment in epidemiological studies