Chemical composition of ferromanganese crust from Tonga platform in the Pacific Ocean

Ferromanganese crusts retrieved from dredges performed on the Tonga platform during cruise L5-82-SP of R/V Samuel P. Lee have been analysed for their metals concentration. Chemical analysis was performed using atomic absorption spectrophotometry

Circulating Sclerostin in Disorders of Parathyroid Gland Function

Context: Sclerostin, a protein encoded by the SOST gene in osteocytes and an antagonist of the Wnt signaling pathway, is down-regulated by PTH administration. Disorders of parathyroid function are useful clinical settings to study this relationship.Objective: the objective of the study was to evaluate sclerostin in two different disorders of parathyroid function, primary hyperparathyroidism and hypoparathyroidism, and to analyze the relationship between sclerostin and PTH, bone markers, and bone mineral density.Design: This is a cross-sectional study.Setting: the study was conducted at a clinical research center.Patients: Twenty hypoparathyroid and 20 hyperparathyroid patients were studied and compared to a reference control group.Results: Serum sclerostin was significantly higher in hypoparathyroid subjects than in hyperparathyroid subjects (P < 0.0001) and controls (P < 0.0001). PTH was negatively associated with sclerostin, achieving statistical significance in hypoparathyroidism (r = -0.545; P = 0.02). the bone turnover markers, cross-linked C-telopeptide of type I collagen (CTX) and amino-terminal propeptide of type I collagen (P1NP), were differently associated with sclerostin according to the parathyroid disorder. in primary hyperparathyroidism, bone turnover markers were associated negatively with sclerostin (for P1NP, r = -0.490; P = 0.03). in hypoparathyroidism, bone turnover markers were associated positively with sclerostin (for CTX, r = +0.571; P = 0.01). Although there was no significant correlation between bone mineral density and sclerostin in either parathyroid disorder, there was a significant positive relationship between sclerostin and bone mineral content in hypoparathyroidism.Conclusions: the results are consistent with the hypothesis that PTH is a regulator of sclerostin in human disorders of parathyroid function. in addition, the results suggest that bone mineral content may be another factor that influences sclerostin. (J Clin Endocrinol Metab 96: 3804-3810, 2011)National Institutes of HealthFood and Drug AdministrationColumbia Univ, Coll Phys & Surg, Dept Med, Div Endocrinol,Metab Bone Dis Unit, New York, NY 10032 USAUniversidade Federal de São Paulo, Div Endocrinol, Dept Med, BR-04044 São Paulo, BrazilUniversidade Federal de São Paulo, Div Endocrinol, Dept Med, BR-04044 São Paulo, BrazilNational Institutes of Health: DK32333National Institutes of Health: DK06950National Institutes of Health: DK066329National Institutes of Health: K24DK074457Food and Drug Administration: FD002525Web of Scienc

Dynamic and Structural Properties of the Skeleton in Hypoparathyroidism

Hypoparathyroidism, a disorder in which PTH is absent, is associated with BMD that is above average. We studied associated structural and dynamic properties of the skeleton in hypoparathyroidism. Thirty-three subjects with hypoparathyroidism and 33 age- and sex-matched control subjects with no known metabolic diseases underwent percutaneous iliac crest bone biopsies after double-labeling with tetracycline. The main outcome was histomorphometric assessment of structural and dynamic skeletal parameters. Subjects with hypoparathyroidism had greater cancellous bone volume (mean ± SD; BV/TV: 23.5 ± 8 versus 19.7 ± 5%, p = 0.02), trabecular width (Tb.Wi: 136.1 ± 37 versus 119.3 ± 21 μm, p = 0.03), and cortical width (Ct.Wi: 923.4 ± 420 versus 753.5 ± 246 μm, p = 0.05) than control subjects. Dynamic skeletal indices, including mineralizing surface (MS: 0.85 ± 1.58 versus 4.27 ± 3.32%, p < 0.0001) and bone formation rate (BFR/BS: 0.006 ± 0.014 versus 0.032 ± 0.028 μm3/μm2/d, p < 0.0001), were profoundly suppressed in the hypoparathyroid subjects. We conclude that hypoparathyroidism is characterized by markedly unusual structural and dynamic properties of bone