Paediatric reference intervals for plasma anti-Müllerian hormone: comparison of data from the Roche Elecsys assay and the Beckman Coulter Access assay using the same cohort of samples.

Background: Autoanalyser methods for the measurement of anti-Müllerian hormone have been introduced into clinical laboratories but few reports of paediatric reference intervals using these new assays have been published.

Methods: After prior evaluation of the Roche Elecsys anti-Müllerian hormone assay against the Beckman Coulter modified second generation anti-Müllerian Hormone enzyme-linked immunosorbent assay using samples from adult females, a cohort of paediatric samples which had previously been assessed using the Beckman Coulter Access anti-Müllerian hormone assay was analysed using the Roche Elecsys anti-Müllerian hormone assay.

Results: The Roche Elecsys anti-Müllerian hormone assay measured significantly lower than the Beckman Coulter modified second generation anti-Müllerian Hormone enzyme-linked immunosorbent assay.

Modification of the Beckman-Coulter second-generation enzyme-linked immunosorbent assay protocol improves the reliability of serum antimüllerian hormone measurement.

Objective: To determine whether the modified Beckman-Coulter 2nd-generation (Gen II) antimüllerian hormone (AMH) assay (Gen IIm) provides more consistent results following storage at room temperature and on dilution than the original Gen II assay, to compare AMH results from the modified assay with those obtained from the original assay, and to assess the relationship between new AMH values and the antral follicle count (AFC).

Design: Cohort.

Setting: Hospital fertility clinic.

The measurement of anti-Müllerian hormone: a critical appraisal.

Context: Measurement of anti-Müllerian hormone (AMH) is perceived as reliable, but the literature reveals discrepancies in reported within-subject variability and between-method conversion factors. Recent studies suggest that AMH may be prone to preanalytical instability. We therefore examined the published evidence on the performance of current and historic AMH assays in terms of the assessment of sample stability, within-patient variability, and comparability of the assay methods.

Suppression of inflammation reduces endothelial microparticles in active systemic lupus erythematosus.

Background: In a prospective observational study, we investigated whether patients with active systemic lupus erythematosus (SLE) had higher indices of endothelial damage and dysfunction than healthy controls and whether improved disease control was associated with improvement in these indices.

Methods: Twenty-seven patients with active SLE (four or more American College of Rheumatology (ACR) criteria) and 22 age-matched controls were assessed. Endothelial microparticles (EMPs; CD31+/annexin V+/CD42b-) were quantified using flow cytometry.

Anti-Mullerian hormone: poor assay reproducibility in a large cohort of subjects suggests sample instability.

Study Question: What is the variability of anti-Müllerian hormone (AMH) concentration in repeat samples from the same individual when using the Gen II assay and how do values compare to Gen I [Diagnostic Systems Ltd (DSL)] assay results?

Summary Answer: The Gen II AMH assay displayed appreciable variability, which can be explained by sample instability.

What Is Known Already: AMH is the primary predictor of ovarian performance and is used to tailor gonadatrophin dosage in cycles of IVF/ICSI and in other routine clinical settings. Thus, a robust, reproducible and sensitive method for AMH analysis is of paramount importance.

Electrophysiological effects of osmotic cell shrinkage in rat pancreatic β-cells.

Electrical and secretory activity in the pancreatic β-cell can be elicited by hypotonic cell swelling, due largely to activation of a volume-regulated anion channel (VRAC) leading to depolarisation and electrical activity. However, β-cell responses to cell shrinkage are less well characterised. The present study has examined the effects of osmotic cell shrinkage on rat pancreatic β-cells.

The reproducibility of serum anti-Müllerian hormone in subfertile women: within and between patient variability.

Serum anti-Müllerian hormone concentrations vary significantly over time and this should be taken into account when tailoring treatment protocols for patients undergoing controlled ovarian hyperstimulation (COH). Compared with FSH, serum anti-Müllerian hormone may have greater discriminatory power because of its modest intrapatient variation and the larger interpatient variation.

Explanations for the lower rates of diabetic neuropathy in Indian Asians versus Europeans.

Objective: Risks of diabetes and cardiovascular disease are elevated worldwide in Indian Asians. However, risks of other diabetes-related complications, i.e.

The relationships between AMH, androgens, insulin resistance and basal ovarian follicular status in non-obese subfertile women with and without polycystic ovary syndrome.

Background: Hyperandrogenaemia and insulin resistance are prominent features of polycystic ovary syndrome (PCOS) and influence the process of folliculogenesis in women with the endocrinopathy. Anti-Müllerian hormone (AMH) levels are elevated in women with PCOS and studies including IVF subjects have shown that this is a reliable marker of ovarian performance. The aims of this prospective study were to assess the relationship between insulin resistance, androgens and AMH, and whether AMH contributes to altered folliculogenesis in non-obese women with PCOS.

Contrasting effects of glycerol and urea transport on rat pancreatic beta-cell function.

Background/aims: Pancreatic beta-cell function is influenced by changes in cell volume. Such volume changes depend on water permeability of the plasma membrane, conferred in part by aquaporins. Islet cells express aquaporin 7 (AQP7), which is permeable to urea and glycerol in addition to water.

Biomarkers of oxidant stress, insulin sensitivity and endothelial activation in rheumatoid arthritis: a cross-sectional study of their association with accelerated atherosclerosis.

Background: Women with rheumatoid arthritis (RA) have increased morbidity and mortality due to coronary heart disease. Chronic systemic inflammation is known to accelerate atherosclerosis and increase arterial stiffness in patients, but other mechanisms may also be involved. Biomarkers of oxidant stress, inflammation, insulinaemia and endothelial dysfunction were measured in blood and urine from 46 RA patients and 48 age-matched controls.

Expression of the electrogenic Na+-HCO3--cotransporters NBCe1-A and NBCe1-B in rat pancreatic islet cells.

It was recently proposed that, in rat pancreatic islets, the production of bicarbonate accounts for the major fraction of the carbon dioxide generated by the oxidative catabolism of nutrient insulin secretagogues. In search of the mechanism(s) supporting the membrane transport of bicarbonate, the possible role of the electrogenic Na(+)-HCO(3) (-)-cotransporters NBCe1-A and NBCe1-B in rat pancreatic islet cells was investigated. Expression of NBCe1-A and NBCe1-B in rat pancreatic islet cells was documented by RT-PCR, western blotting, and immunocytochemistry.

Local inflammation and hypoxia abolish the protective anticontractile properties of perivascular fat in obese patients.

Background: Inflammation in adipose tissue has been implicated in vascular dysfunction, but the local mechanisms by which this occurs are unknown.

Methods And Results: Small arteries with and without perivascular adipose tissue were taken from subcutaneous gluteal fat biopsy samples and studied with wire myography and immunohistochemistry. We established that healthy adipose tissue around human small arteries secretes factors that influence vasodilation by increasing nitric oxide bioavailability.

Stimulus-secretion coupling of hypotonicity-induced insulin release in BRIN-BD11 cells.

The stimulus-secretion coupling for hypotonicity-induced insulin release was investigated in BRIN-BD11 cells. A 50 mM decrease in extracellular NaCl caused a twofold increase in insulin release. The release of insulin evoked by hypotonicity progressively decreased in an exponential manner.

Possible role of carbonic anhydrase in rat pancreatic islets: enzymatic, secretory, metabolic, ionic, and electrical aspects.

The presence of carbonic anhydrase (type V) was recently documented in rat and mouse pancreatic islet beta-cells by immunostaining and Western blotting. In the present study, the activity of carbonic anhydrase was measured in rat islet homogenates and shown to be about four times lower than in rat parotid cells. The pattern for the inhibitory action of acetazolamide on carbonic anhydrase activity also differed in islet and parotid cell homogenates, suggesting the presence of different isoenzymes.

Hyperinsulinemia, insulin resistance, and circulating oxidized low density lipoprotein in women with systemic lupus erythematosus.

Objective: Women with systemic lupus erythematosus (SLE) have increased risk of coronary heart disease (CHD) that is not fully explained by the classic CHD risk factors. Insulin resistance is an established risk factor for CHD in the general population. We compared insulin secretion and sensitivity in patients with SLE and healthy controls, and assessed the prevalence of the metabolic syndrome in women with SLE and its relation to circulating oxidized low density lipoprotein (ox-LDL).

Actions of antipsychotic drugs on pancreatic beta-cell function: contrasting effects of clozapine and haloperidol.

The use of antipsychotic drugs is known to be associated with a number of adverse metabolic side effects, including diabetes mellitus. These side effects could be, at least in part, the result of impaired islet cell function, although the underlying mechanisms are unknown. We have studied the effects of the atypical antipsychotic clozapine and of the conventional drug haloperidol on electrical and secretory activity in rat pancreatic beta-cells.

Progestogens of varying androgenicity and cardiovascular risk factors in postmenopausal women receiving oestrogen replacement therapy.

Objective: Medroxyprogesterone (MP) was used as the progestogen in randomized clinical trials of postmenopausal hormone replacement on cardiovascular risk. To attempt to understand the lack of benefit in these trials, we have examined the effects of MP and two other progestogens, the less androgenic desogestrel (DG) and the more androgenic norethisterone (NE), on cardiovascular risk factors against a background of oestrogen therapy.

Design And Measurements: Thirty-four women were treated with conjugated equine oestrogens (CEE) 0.

Inhibition of glucose-induced electrical activity in rat pancreatic beta-cells by DCPIB, a selective inhibitor of volume-sensitive anion currents.

We have investigated the effects of the ethacrynic acid derivative 4-(2-butyl-6,7-dichloro-2-cyclopentyl-indan-1-on-5-yl) oxobutyric acid (DCPIB), an inhibitor of the volume-sensitive anion channel (VSAC), on electrical activity and insulin secretion in rat pancreatic beta-cells. DCPIB inhibited whole-cell VSAC currents in beta-cells with IC50 values of 2.2 and 1.