[Measurement of angiotensin-I-converting enzyme in the blood: help for method validation].

Blood angiotensin-converting enzyme (ACE) assay is now realized by the determination of enzyme activity on synthetic substrate, mostly furylacryloyl-phenylalanyl-L-glycyl-L-glycine (FAPGG). The matrix can be serum or heparin-plasma, with or without a separator; the assay developed on serum or plasma is not adapted to other matrix such as cerebrospinal fluid where the ACE activity is much lower. This assay has been adapted on a number of automated biochemistry analyzers with the specifications of the supplier of reagents, sometimes with modification of volumes or times for analysis.

Exposure to Glucocorticoids in the First Part of Fetal Life is Associated with Insulin Secretory Defect in Adult Humans.

Objective: High glucocorticoid levels in rodents inhibit development of beta cells during fetal life and lead to insulin deficiency in adulthood. To test whether similar phenomena occur in humans, we compared beta-cell function in adults who were exposed to glucocorticoids during the first part of fetal life with that of nonexposed subjects.

Research Design And Methods: The study was conducted in 16 adult participants exposed to glucocorticoids during the first part of fetal life and in 16 nonexposed healthy participants with normal glucose tolerance who were matched for age, sex, and body mass index (BMI).

Sex Difference In the Effect of Fetal Exposure to Maternal Diabetes on Insulin Secretion.

We previously showed that fetal exposure to maternal type 1 diabetes (T1D) is associated with altered glucose-stimulated insulin secretion in adult offspring. Here, we investigated whether this -cell defect displays a sex dimorphism. Twenty-nine adult nondiabetic offspring of T1D mothers (ODMs) were compared with 29 nondiabetic offspring of T1D fathers.

Zinc transporter 8 autoantibodies assessment in daily practice.

Objectives: Zinc transporter 8 (ZnT8) is specifically expressed in the pancreatic β-cell and is more restricted in its tissue distribution than other auto-antigens as glutamic acid decarboxylase 65 (GAD) and insulinoma-associated antigen-2 (IA2). ZnT8 autoantibodies (ZnT8A) assessment allows identifying rapid progression to clinical onset of the disease. We evaluated the prevalence of ZnT8A in adults of different ethnic and phenotypic groups and analyzed its potential utility as additional marker of autoimmunity in daily practice.

Evaluation of a new automated assay for the measurement of circulating 1,25-dihydroxyvitamin D levels in daily practice.

Background And Objective: 1,25-dihydroxyvitamin D [1,25(OH)2D] is the most important vitamin D metabolite in regulating calcium and phosphorus metabolism and bone resorption. It is measured in plasma for diagnosis and management of patients with disorders influencing vitamin D metabolism. The most common methods for 1,25(OH)2D quantification are competitive isotopic I(125) immunoassays.

Osteoprotegerin is not a determinant of metabolic syndrome in sub-Saharan Africans after age adjustment.

Objectives: Osteoprotegerin (OPG), a soluble member of tumor necrosis factor receptor superfamily that inhibits bone resorption, has been suggested as a cardiovascular risk factor in humans. In this study, we aim to investigate the potential relationship between OPG and MetS (MetS) in a sub-Saharan African population.

Methods: Four hundred and eleven volunteers (152 men, 259 women) aged ≥18 years recruited from the general population in Douala and Edea, Cameroon participated in this study.

β- and α-cell dysfunctions in africans with ketosis-prone atypical diabetes during near-normoglycemic remission.

Objective: Ketosis-prone atypical diabetes (KPD) is a subtype of diabetes in which the pathophysiology is yet to be unraveled. The aim of this study was to characterize β- and α-cell functions in Africans with KPD during remission.

Research Design And Methods: We characterized β- and α-cell functions in Africans with KPD during remission.

Potential utility of high preoperative levels of serum type I collagen markers in postmenopausal women with primary hyperparathyroidism with respect to their short-term variations after parathyroidectomy.

We evaluated short-term changes in serum amino-terminal procollagen propeptide (P1NP) and cross-linked C-terminal telopeptide (betaCTX) of type I collagen after parathyroidectomy (PTX) in 41 postmenopausal women with primary hyperparathyroidism (PHPT). Serum levels of 25-hydroxyvitamin D, intact PTH, calcium, phosphate, albumin, creatinine, P1NP, and betaCTX were measured before and 2 days after PTX. Their P1NP and betaCTX levels were compared with those measured in 41 normally menstruating and 30 postmenopausal controls.

Differences in circulating insulin levels following glargine administration.

Objectives: To evaluate two-site non competitive insulin immunoassays [BI-INSULIN assay (IRMA) and an electro-chemiluminescent immunoassay (ECLIA)] in routine practice.

Design And Methods: We studied 145 consecutive patients attending our Endocrine Department for general endocrine explorations and metabolic status investigations.

Results: The ECLIA yielded higher results than IRMA in all but six patients treated by glargine.

Diagnosis of adrenal insufficiency in severe sepsis and septic shock.

Rationale: Diagnosis of adrenal insufficiency in critically ill patients has relied on random or cosyntropin-stimulated cortisol levels, and has not been corroborated by a more accurate diagnostic standard.

Objective: We used the overnight metyrapone stimulation test to investigate the diagnostic value of the standard cosyntropin stimulation test, and the prevalence of sepsis-associated adrenal insufficiency.

Methods: This was an inception cohort study.

Unexpected serum parathyroid hormone profiles in some patients with primary hyperparathyroidism.

Background: Third-generation parathyroid hormone (PTH) assays have been reported to measure only intact PTH(1-84), in contrast to second-generation assays, which also detect PTH(7-84) fragments. Higher PTH measurements were observed with third- than with second-generation PTH assays in a few patients with either severe primary hyperparathyroidism or parathyroid carcinoma.

Methods: We analyzed biological data [second- and third-generation PTH assays, 25-hydroxyvitamin D (25-OHD), calcium, and phosphate concentrations] obtained before and after surgery for 2 groups of patients selected from a large series of consecutive patients with primary hyperparathyroidism (PHPT): 7 female patients with surgically and histologically confirmed PHPT (group 1) and a matched group (group 2).

Serum bioavailable testosterone: assayed or calculated?

Background: Bioavailable testosterone (BT), circulating testosterone not bound to sex hormone-binding globulin (SHBG), is thought to easily penetrate cells. We compared BT measurements obtained by assays with those obtained by calculation with different testosterone association constants.

Methods: We obtained sera from 2 groups of hypogonadal men [group 1 (G1), 1421 samples; group 2 (G2), 170 samples] and a group of healthy men [group 3 (G3), 109 samples].

Third- or second-generation parathyroid hormone assays: a remaining debate in the diagnosis of primary hyperparathyroidism.

Background: Since the demonstration that the second-generation PTH assays, also called intact PTH assays, recognize a non-1-84 PTH fragment in addition to the intact 1-84 PTH, new PTH assays defined as third-generation assays have been commercialized. Two previous studies aimed at evaluating whether these third-generation PTH assays improved the diagnostic sensitivity for primary hyperparathyroidism (PHPT), but they yielded opposite results.

Methods: In the present study we compared two second-generation PTH assays (the total intact PTH assay from Scantibodies Laboratory, Inc.

Development of a highly sensitive and specific new testosterone time-resolved fluoroimmunoassay in human serum.

A new time-resolved fluoroimmunoassay (TR-FIA) of testosterone in serum is described, using a biotinylated testosterone tracer, with a long spacer arm between biotin and testosterone, coupled to the C3 of the testosterone: a biotinylaminodecane carboxymethyloxime testosterone. This tracer affords a great sensitivity of the standard curve, because a amount of 0.3 pg of testosterone can be significantly measured on the testosterone standard curve.

Plasma 11beta-hydroxy-4-androstene-3,17-dione: comparison of a time-resolved fluoroimmunoassay using a biotinylated tracer with a radioimmunoassay using a tritiated tracer.

The plasma concentration of 11beta-hydroxy-4-androstene-3,17-dione (11beta) is very high in 21-hydroxylase deficiency, Cushing's syndrome, and hyperandrogenism of adrenal origin, and very low in congenital 11-hydroxylase deficiency and adrenal insufficiency. Thus, when plasma 4-androstenedione is elevated, it is useful to measure the plasma 11beta level in order to determine the adrenal or ovarian origin of the hyperandrogenism. To eliminate disadvantages related to the 11beta radioimmunoassay (RIA), which uses a tritiated tracer, as well as the high cost associated with scintillation proximity assay (SPA), we developed a non-isotopic 11beta assay that utilizes an 11beta-biotin conjugate synthesized in our laboratory to measure time-resolved fluorescence after addition of streptavidin-europium to microtitration wells.