Hemoglobin Providence (β82 Lys > Asn, Asp) and lower-than-expected HbA1c in a nonadherent teenager with type 1 diabetes: a case report and literature review.

Endocrinologists should have a high index of suspicion for a Hb variant when the HbA1c is not consistent with other indices of glycemic control.

Decreased heart rate variability is associated with increased transcranial Doppler velocities in children with sickle cell disease.

Objective: To explore the relationship between 24-hour blood pressure (BP) variability, heart rate (HR) variability, and transcranial Doppler velocity (TCDV) in a cohort of pediatric sickle cell disease (SCD) patients.

Design, Setting, And Participants: This is a retrospective study of 11 children aged 8-18 years with SCD who previously underwent 24-hour ambulatory BP monitoring and TCDV measurements.

Interventions: Medical records were reviewed for TCDV and 24-hour ABP data.

Aromatase and 5alpha-reductase inhibition during an exogenous testosterone clamp unveils selective sex steroid modulation of somatostatin and growth hormone secretagogue actions in healthy older men.

Background: How endogenous testosterone (Te), 5alpha-dihydrotestosterone (DHT), and estradiol (E(2)) regulate pulsatile GH secretion is not understood.

Hypothesis: Conversion of Te to androgenic (Te-->DHT) or estrogenic (Te-->E(2)) products directs GH secretion. SUBJECTS AND LOCATION: Healthy older men (N = 42, ages 50-79 yr) participated at an academic medical center.

Testosterone supplementation in older men restrains insulin-like growth factor's dose-dependent feedback inhibition of pulsatile growth hormone secretion.

Background: Pulsatile GH secretion declines in older men. The causal mechanisms are unknown. Candidates include deficient feedforward (stimulation) by endogenous secretagogues and excessive feedback (inhibition) by GH or IGF-I due to age and/or relative hypoandrogenemia.

Clinical review: treatment of pediatric obesity: a systematic review and meta-analysis of randomized trials.

Context: The efficacy of treatments for pediatric obesity remains unclear.

Objective: We performed a systematic review of randomized trials to estimate the efficacy of nonsurgical interventions for pediatric obesity.

Data Sources: Librarian-designed search strategies of nine electronic databases from inception until February 2006, review of reference lists from published reviews, and content expert advice provided potentially eligible studies.

Clinical review: behavioral interventions to prevent childhood obesity: a systematic review and metaanalyses of randomized trials.

Context: The efficacy of lifestyle interventions to encourage healthy lifestyle behaviors to prevent pediatric obesity remains unclear.

Objective: Our objective was to summarize evidence on the efficacy of interventions aimed at changing lifestyle behaviors (increased physical activity, decreased sedentary activity, increased healthy dietary habits, and decreased unhealthy dietary habits) to prevent obesity.

Data Sources: Data sources included librarian-designed searches of nine electronic databases, references from included studies and reviews (from inception until February 2006), and content expert recommendations.

Estradiol supplementation in postmenopausal women attenuates suppression of pulsatile growth hormone secretion by recombinant human insulin-like growth factor type I.

Background: Why pulsatile GH secretion declines in estrogen-deficient postmenopausal individuals remains unknown. One possibility is that estrogen not only enhances stimulation by secretagogues but also attenuates negative feedback by systemic IGF-I. SITE: The study took place at an academic medical center.

Estrogen elevates the peak overnight production rate of acylated ghrelin.

Context: Acylated ghrelin is the putatively bioactive GH secretagogue.

Hypothesis: Estradiol (E2) stimulates the synthesis rather than inhibits the metabolic clearance of acylated ghrelin.

Setting: The study took place at an academic medical center.

Estrogen supplementation selectively enhances hypothalamo-pituitary sensitivity to ghrelin in postmenopausal women.

Context: Sex-steroid hormones amplify pulsatile GH secretion by unknown mechanisms. Ghrelin is the most potent natural GH secretagogue discovered to date. A plausible unifying postulate is that estradiol (E(2)) enhances hypothalamo-pituitary sensitivity to ghrelin (a physiological effect).

Gonadal status and body mass index jointly determine growth hormone (GH)-releasing hormone/GH-releasing peptide synergy in healthy men.

Context: Sex steroid hormones potentiate whereas increased body mass index (BMI) represses GH secretion. Whether sex steroids modify the negative effect of BMI on secretagogue-induced GH secretion in men is not known. The issue is important in designing GH-stimulation regimens that are relatively insensitive to both gonadal status and adiposity.

Tripartite control of growth hormone secretion in women during controlled estradiol repletion.

Context: Studies of how aging attenuates GH secretion are confounded by differences in sex-steroid milieus, abdominal visceral fat mass (AVF), and IGF-I concentrations and limited in interpretability by the use of pharmacological doses of secretagogues.

Hypothesis: In a controlled estrogenic milieu, near-physiological secretagogue drive will unmask distinct influences of age, AVF, and IGF-I on GH secretion.

Location: The study was conducted at an academic medical center.