EFFECT OF EXPERIMENTAL DYSGLYCEMIA ON UNDER-CARBOXYLATED OSTEOCALCIN PRODUCTION IN HUMAN PRIMARY OSTEOBLAST-LIKE CELL CULTURES.

CONTEXT: The undercarboxylated form of osteocalcin (ucOC) and osteoprotegerin (OPG) are bone-derived molecules involved in the endocrine crosstalk governing the bone, the adipose tissue and the pancreas. In addition, glucocorticoids are major determinants of both insulin resistance and osteoporosis. OBJECTIVE: We aimed to investigate the response of ucOC and OPG to dysglycemia and/or dexamethasone (DXM) in primary human osteoblastic cell (HOC) cultures. DESIGN AND METHODS: Third-passage sub-confluent primary HOC cultures were treated with glucose: 2.8 mmol/L, 5.6 mmol/L, 11.1 mmol/L and 28 mmol/L, respectively. Alternatively, HOC cultures were subjected to DXM 1 µmol/L. In more complex experiments, HOC cultures were pre-treated with glucose (5.6 mmol/L) with/without insulin (1 pmol/L) followed by DXM (1 µmol/L). 24-hours post-treatment, culture medium ucOC and OPG were measured by ELISA. RESULTS: ucOC production differed significantly (p<0.05) between cell groups, decreasing in a dose-dependent manner as glucose concentration in the medium increased. Insulin prevented this effect. OPG levels appeared not to be significantly influenced by the hyperglycemic culture medium and were not related to ucOC concentration (p>0.05). Addition of DXM resulted in significantly lower ucOC concentrations compared to vehicle-treated cells (p<0.05). However, the effect of insulin co-treatment on ucOC was not counteracted by DXM (p<0.05). CONCLUSIONS: An obvious alteration of OC production/metabolism was observed as glucose levels changed in the bone microenvironment, to potentially be involved in diabetes-related osteopenia. DXM suppressed ucOC levels however not in insulin-rich environment.

The effect of the D1-C785T polymorphism in the type 1 iodothyronine deiodinase gene on the circulating thyroid hormone levels in Romanian women with preeclampsia. Association with the degree of severity and pregnancy outcome of preeclampsia.

AIM: To investigate the biochemical and genetic thyroid status in women with preeclampsia by the determination of serum FT3 and FT4 levels in association with D1-C785T genotypes. METHODS: We genotyped using PCR-RFLP methods 50 women with preeclampsia and 50 normotensive pregnant women. RESULTS: FT3 levels (pg/ml, 2.63 ± 0.56 vs. 2.91 ± 1.41) were low, and FT4 levels (ng/dl, 1.11 ± 0.3 vs. 0.88 ± 0.14) were high in women with preeclampsia compared to normal pregnant women. The association with severe preeclampsia was stronger for the homozygous T/T genotype (OR 6.57, p = 0.029). Women with preeclampsia with the D1-T785 mutated allele had lower FT3 levels (pg/ml, 2.31 ± 0.81 vs. 3.04 ± 0.39, p < 0.001), higher FT4 levels (ng/dl, 1.32 ± 0.87 vs. 0.84 ± 0.24, p = 0.009) than women with preeclampsia with the D1-C/C genotype. Significant decrease in serum FT3 levels in positive women with severe preeclampsia compared to women negative for this genetic variation (pg/ml, 1.59 ± 0.74 vs. 2.77 ± 0.23, p = 0.003) was observed. Women with severe preeclampsia, positive for the mutated T785 allele, delivered at a significantly lower gestational age (31.75 ± 3.69 vs. 38.66 ± 3.21 weeks, p = 0.035) neonates with a lower birth weight (1861.11 ± 869.9 vs. 3500 ± 424.26 g, p = 0.023) compared to women negative for the same allele. CONCLUSIONS: Thyroid hormone levels and the D1-C785T polymorphism, alone or in combination, correlate with the severity of preeclampsia. The D1-C785T polymorphism influences the outcome of pregnancy in severe preeclampsia.

Estimation of the liquid-vapor spinodal from interfacial properties obtained from molecular dynamics and lattice Boltzmann simulations.

Interfacial pressure and density profiles are calculated from molecular dynamics and lattice Boltzmann simulations of a liquid film in equilibrium with its vapor. The set of local values of tangential pressure and density along an interface exhibits a van der Waals-type loop; starting from the stable vapor bulk phase one passes through metastable and unstable states to the stable liquid bulk phase. The minimum and maximum values of the profile of tangential pressure are related to the liquid and vapor spinodal states, respectively. The spinodal pressures turn out to be linearly related to the extreme values of the tangential pressure in the interface. The comparison with equations of state shows good agreement with the simulation results of the spinodals. In addition the properties of the metastable region are obtained. Based on this investigation a method is proposed for the estimation of the liquid spinodal from experimentally obtained interfacial properties. Estimations for water and helium are presented.

Effects of parenteral pharmacological magnesium loading on insulin secretion in experimental thyrotoxicosis.

Thyrotoxicosis is characterised by decreased magnesium pool and also insulin resistance. The present study is evaluating the parameters of glucose metabolism under pharmacological magnesium loading in experimentally induced thyrotoxicosis, in rats. Insulin secretion was significantly increased in thyrotoxicosis compared to controls, expressing probably the status of insulin resistance due to thyroxine excess. After intraperitoneal magnesium infusion, plasma magnesium reached pharmacologically high concentrations and insulin secretion decreased significantly, but this decrease was not accompanied by alterations of glucose homeostasis. In controls, we also found a tendency towards the decrease of insulin secretion after magnesium loading, but it did not reach statistical significance. Thus, insulin secretion seems more sensitive to the inhibitory effects of magnesium overload in experimental thyrotoxicosis.