Endocrine journal
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Vitamin D is an important regulator of bone health. Previous studies examining the association between vitamin D deficiency and osteoporotic fractures have reported conflicting results. The relationship between vitamin D status and risk of vertebral fractures in diabetic patients is unknown. ⋯ However, there was no significant association between vitamin D status and the prevalence of vertebral fractures in women (14.4% vs. 19.2% vs. 26.6%, p for trend=0.111). After adjusting for multiple confounding factors, men with a serum 25(OH)D concentration of less than 20 ng/mL were associated with an increased risk of vertebral fractures (OR 7.87; 95% CI 1.69-36.71), but not women. In conclusion, serum 25(OH)D levels below 20 ng/mL were associated with an increased vertebral fracture risk in men with type 2 diabetes.
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Observational Study
Relationship between metformin use, vitamin B12 deficiency, hyperhomocysteinemia and vascular complications in patients with type 2 diabetes.
Aim of the study was to clarify the relationship between metformin-induced vitamin B12 (B12) deficiency, hyperhomocysteinemia and vascular complications in patients with type 2 diabetes. Serum B12 concentrations, homocysteine plasma levels, the presence of retinopathy and history of macroangiopathy (stroke or coronary heart disease) were analyzed in patients without renal dysfunction (serum creatinine<115 μmol/L). Firstly, B12 status was analyzed in 62 consecutive metformin-treated patients. ⋯ In ten B12 deficient patients, B12 supplementation (1,500 μg/day) for 2.2±1.0 months with continued use of metformin raised B12 levels: 152±42 and 299±97 pmol/L before and after treatment, respectively (P<0.01). Metformin-induced B12 lowering in diabetes was associated with elevation of homocysteine, and hyperhomocysteinemia was independently related to retinopathy. Metformin-induced B12 deficiency was correctable with B12 supplementation.
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Adult hippocampal neurogenesis is important in mediating hippocampal-dependent learning and memory. Exogenous ghrelin is known to stimulate progenitor cell proliferation in the dentate gyrus of adult hippocampus. The aim of this study was to investigate the role of endogenous ghrelin in regulating the in vivo proliferation and differentiation of the newly generating cells in the adult hippocampus using ghrelin knockout (GKO) mice. ⋯ However, these functional deficiencies were attenuated by ghrelin administration. These results suggest that ghrelin directly induces proliferation and differentiation of adult neural progenitor cells in the SGZ. Our data suggest ghrelin may be a plausible therapeutic potential to enhance learning and memory processes.
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The aim of this study was to determine whether dexmedetomidine (DEX) and medetomidine (MED), α2-adrenergic agonists clinically used as sedatives, influence insulin secretion from rat pancreatic islets. Islets were isolated from adult male Wistar rats after collagenase digestion. Static incubation was used to determine effects of DEX or MED on insulin secretion and ionic-channel currents of β-cells. ⋯ However, when tolbutamide, a specific blocker of the ATP-sensitive K+ channel (KATP channel), was present, the magnitude of MED inhibition of insulin secretion was not influenced, suggesting that Kv-channel activity alteration, but not that of KATP channels, is involved in MED-associated insulin secretory inhibition. The Kv-channel currents were increased during 1 nM MED exposure at membrane potentials ranging from -30 mV to -10 mV, where action potentials were generated in response to glucose stimulation. These results indicate that DEX and MED inhibit insulin secretion through an α2-adrenoceptor and PTX-sensitive GTP-binding protein pathway that eventually involves Kv channel activation and Ca2+ channel inhibition.
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Hyponatraemia (serum sodium concentration<135 mmol/L) is the most common electrolyte disorder in hospitalised patients. We analysed the safety and efficacy of tolvaptan in the treatment of hyponatraemia in hospitalised inpatients and report the first consecutive retrospective clinical case series report based on a single centre experience from the United Kingdom. We sought out the case records of all patients treated with tolvaptan for hyponatraemia over a period of 19 months; 15 episodes of treatment with tolvaptan in 14 patients were analysed. ⋯ The maximum rate of change of sodium was observed in the first 24 hours of therapy (mean 6.7 ± 2.8, 1 to 11 mmol/L) with no patient exceeding 12 mmol/L in 24 hours and 18 mmol/L in 48 hours at any point whilst on tolvaptan. No patient developed the osmotic demyelination syndrome. Tolvaptan appears to be safe and effective in the management of hospitalised inpatients with definitive euvolaemic hyponatraemia when close monitoring is observed.