Preanalytical, analytical, gestational and pediatric aspects of the S100B immuno-assays.

BACKGROUND: Traumatic brain injury management is a tricky issue in children and pregnant women (due to adverse effects of computer tomography). To facilitate management, we report the main analytical performances and reference ranges for blood tests for the well-established S100B biomarker in under-16 children on a DiaSorin® Liaison XL analyzer and in pregnant women on DiaSorin® Liaison XL and Roche Diagnostics® Cobas e411 analyzers. METHODS: Serum S100B concentrations were determined by chemiluminescent immunoassay on a DiaSorin® analyzer in a population of 409 healthy children aged 0-16 years and on DiaSorin®/Roche Diagnostics® instruments in a population of 50 pregnant women (one blood sample for each trimester). The analytical performances of both instruments and the influence of blood cells and skin pigmentation on the assay were also studied. RESULTS: For children, four age-groups emerged, i.e. 0-3 months (mean: 0.97 µg/L; standard deviation (SD): 0.36; 95th percentile: 1.55), 4-9 months (mean: 0.58 µg/L; SD: 0.30; 95th: 1.18), 10-24 months (mean: 0.31 µg/L; SD: 0.12; 95th: 0.54) and 2-16 years (mean: 0.20 µg/L; SD: 0.07; 95th: 0.32). For pregnant women, serum S100B concentrations were similar to defined ranges for adults and not significantly different between trimesters on DiaSorin® (p=0.652)/Roche Diagnostics® (p=0.877) analyzers. We also found S100B expression (protein, total mRNA) in lymphocytes, an influence of skin pigmentation, and good analytical performances for both instruments. CONCLUSIONS: Data provided here is useful for interpreting serum S100B test results, in terms of preanalytical conditions, analytical performances, pediatric and pregnancy' environment.

Expression of dlx genes in the normal and regenerating brain of adult zebrafish.

Dysfunctions in the GABAergic system lead to various pathological conditions and impaired inhibitory function is one of the causes behind neuropathies characterized by neuronal hyper excitability. The Dlx homeobox genes are involved in the development of nervous system, neural crest, branchial arches and developing appendages. Dlx genes also take part in neuronal migration and differentiation during development, more precisely, in the migration and differentiation of GABAergic neurons. Functional analysis of dlx genes has mainly been carried out in developing zebrafish embryos and larvae, however information regarding the expression and roles of these genes in the adult zebrafish brain is still lacking. The extensive neurogenesis that takes place in the adult zebrafish brain, makes them a good model for the visualization of mechanisms involving dlx genes during adulthood in physiological conditions and during regeneration of the nervous system. We have identified the adult brain regions where transcripts of dlx1a, dlx2a, dlx5a and dlx6a genes are normally found and have confirmed that within telencephalic domains, there is high overlapping expression of the four dlx paralogs with a marker for GABAergic neurons. Co-localization analyses carried with the Tg(dlx6a-1.4kbdlx5a/dlx6a:GFP) reporter line have also shown that in some areas of the diencephalon, cells expressing the dlx5a/6a bigene may have a neural stem cell identity. Furthermore, investigations in a response to stab wound lesions, have demonstrated a possible participation of the dlx5a/6a bigene, most likely of dlx5a, during regeneration of the adult zebrafish brain. These observations suggest a possible participation of dlx-expressing cells during brain regeneration in adult zebrafish and also provide information on the role of dlx genes under normal physiological conditions in adults.

Utility of S100B Serum Level for the Determination of Concussion in Male Rugby Players.

BACKGROUND: The incidence of concussion in professional direct-contact sports, particularly in rugby, has increased in recent years. To date, cognitive assessment is the most common means of determining whether a concussed player can return to the game. Serum S100B assay, an objective blood test known to be useful in brain injury management, may offer a novel additional approach to the management of concussed male rugby players. OBJECTIVE: The aim of this study was to investigate the S100B utility for the determination of concussion in a professional 15-players-a-side rugby team. METHODS: Thirty-nine male rugby players were included in a prospective study during the 2014-2015 French championship season. Serum sampling was carried out several times at baseline and after a match and/or a concussion, at set times (2, 36 h). Serum S100B concentrations were determined using chemiluminescence immunoassay on a Roche Diagnostics® instrument. RESULTS: The players' basal serum S100B was stable during the season and was not correlated with anthropometric data, body composition, or creatine kinase concentration. A significant increase in S100B concentration within 2 h after a game (without concussion) was observed. This increase was correlated with the number of body collisions during a match. Seventy-seven assays were performed 36 h after a game, including the follow-up of five concussed players. Thirty-six hours after a match, an increase of a minimum of 20 % compared with individual basal concentrations identified concussion with 100 % sensitivity and 81 % specificity. CONCLUSION: S100B measured 36 h after a match is thus a discriminating test to identify concussion in a male rugby player, with a 100 % negative predictive value.