[Proinsulin: physiology, measurement, and interest in clinical biology].

The proinsulin molecule results from the cleavage of pre-pro-insulin, produced in pancreatic beta cells. Its subsequent -cleavage allows the release of insulin, the key hormone of glycemia regulation and C-peptide in equimolar proportions. During fasting trial, insulinoma diagnosis relies on inadequately high insulin and C-peptide serum levels concomitant with an hypoglycemia.

Diagnostic performance of an automated immunoassay for salivary cortisol.

Automated immunoanalysis (AI) is an interesting alternative for measuring salivary cortisol, as the gold standard HPLC-MS/MS method is not yet readily available. The aim of this study was to evaluate the diagnostic performance of salivary cortisol immunoassay on the iSYS immunoanalyzer in adrenal dynamic tests. Cortisol was measured on iSYS and on HPLC-MS/MS in saliva samples collected after 1mg-dexamethasone suppression test (DST) in 115 patients suspected of Cushing syndrome, and during Synacthen® stimulation test (SST) in 108 patients suspected of adrenal insufficiency.

Biochemical Screening for Fetal Trisomy 21: Pathophysiology of Maternal Serum Markers and Involvement of the Placenta.

It is now well established that maternal serum markers are often abnormal in fetal trisomy 21. Their determination is recommended for prenatal screening and pregnancy follow-up. However, mechanisms leading to abnormal maternal serum levels of such markers are still debated.

C-peptide level concomitant with hypoglycemia gives better performances than insulin for the diagnosis of endogenous hyperinsulinism: a single-center study of 159 fasting trials.

Introduction: Diagnosis of endogenous hyperinsulinism relies on the occurrence of a hypoglycemia, concomitant with inadequate high insulin and C-peptide levels. However, diagnostic cutoffs are not consensual among the different learned societies. The objective of this work was to propose optimized cutoffs for these three parameters for the diagnosis of endogenous hyperinsulinism.

Pattern of secretion of pregnancy-associated plasma protein-A (PAPP-A) during pregnancies complicated by fetal aneuploidy, in vivo and in vitro.

Background: Pregnancy-associated placental protein-A (PAPP-A) is a metalloprotease which circulates as an hetero-tetramer in maternal blood. Its maternal serum concentration in fetal trisomy 21 is decreased during the first trimester, so that PAPP-A is a useful screening biomarker. However, the regulation of PAPP-A placental secretion is unclear.

[Biology and markers of preeclampsia].

Preeclampsia is a syndrome specific of pregnancy and placenta diagnosed after 20 WG on the association of an hypertension and a proteinuria. It is responsible for significant maternal-fetal morbidity and mortality which justify the development of markers for screening, diagnosis and prognosis. These markers are actors or witnesses to the various stages and mechanisms of the disease : the initial defect of trophoblast invasion and remodeling of uterine arteries (proteases [PAPP-A, ADAM-12, uPA, MMPs], their inhibitors, and angiogenic factors [PlGF, sflt-1, s-eng]) which induces hydrostatic abnormalities (uterine doppler) and placental hypoperfusion with dysoxia (HIF-1α) and oxidative stress (free radicals, peroxynitrites, oxidized LDL).

[Assessment of AFP in amniotic fluid: comparison of three automated techniques].

Ultrasound scanning is useful to detect neural tube defect (NTD) but scarcely distinguished between closed NTD and open NTD, which had very different prognosis. An amniotic fluid punction is thus mandatory to search for an increase in alpha foeto protein (AFP) levels and for the presence of acetylcholinesterase which identified open NTD. However, AFP levels fluctuate both with the gestational age and the assay used.