Rajata Rajatanavin

Reduced attenuation of bone resorption after oral glucose in type 2 diabetes

Objectiveu2002 To investigate the effect of oral glucose on bone resorption and osteoprotegerin (OPG) in subjects with varying degrees of glucose tolerance.

Discrepant influence of vitamin D status on parathyroid hormone and bone mass after two years of calcium supplementation

Objectiveu2002 To investigate the influence of vitamin D status on parathyroid hormone and bone mass after a 2‐year supplementation of calcium alone.

Exogenous subclinical hyperthyroidism during adolescence: effect on peak bone mass.

BACKGROUNDnChronic subclinical hyperthyroidism induced by suppressive doses of L-thyroxine (L-T4) therapy, so-called exogenous subclinical hyperthyroidism, may cause diminished bone mass in postmenopausal women. The effect of subclinical hyperthyroidism during childhood and adolescence on peak bone mass, however, has not been evaluated.nnnOBJECTIVEnTo determine whether exogenous subclinical hyperthyroidism during adolescence, the period of critical bone mass acquisition, would reduce peak bone mass.nnnPATIENTS AND METHODSnEighteen female adolescents and young adults with Hashimotos thyroiditis and euthyroid goiter (aged 22.4 +/- 4.4 years) who had been treated with suppressive doses of L-T4, 127.5 +/- 23.7 microg/day, during adolescence (age at onset of subclinical hyperthyroidism, 14.2 +/- 1.5 years) for 6.3 +/- 3.4 years were enrolled in the study. Twenty-nine healthy female volunteers matched for age, weight, height and body mass index served as the controls. Bone mineral density (BMD) was measured by dual energy X-ray absorptiometry.nnnRESULTSnBMD of the lumbar spine, radius, Wards triangle and total body were comparable in the two groups. In contrast, BMD of the femoral neck, trochanter and shaft of patients was slightly higher than those of controls. There were no correlations between BMD values and clinical parameters.nnnCONCLUSIONnExogenous subclinical hyperthyroidism during adolescence has no demonstrable detrimental effect on peak bone mass attainment.

Use of in vivo gene expression of isolated bone marrow mesenchymal stromal cells to study the pathophysiology of osteoporosis in patients with severe thalassemia.

We compared osteoblast differentiation gene expressions in the isolated CD105+ mesenchymal stromal cells from bone marrow in 10 patients with severe thalassemia and 12 normal donor controls. The fold expressions of osteoblast differentiation genes of CD105+ cells from patients with thalassemia were lower than those of normal donors but increased after being cultured in Dulbeccos modified Eagles medium with 10% fetal calf serum. Moreover, the fold expressions of these genes of CD105+ cells from normal donors when cultured with 10% pooled serum of patients with thalassemia were lower than when cultured with 10% pooled serum of normal donors. We have also presented the evidence of reversible suppressed expression of these genes in CD105+cells from patients with thalassemia when cultured in pooled serum of normal donors. Moreover, healthy donor CD105+ cells exhibited lower expression of these genes when cultured in pooled serum of patients with thalassemia compared with pooled serum of normal donors indicating the existence of circulating factors in thalassemic serum impairing the differentiation of mesenchymal stromal cells to osteoblasts.