No abstract

Calcaneus bone mineral density (BMD) of 738 Japanese women (605 healthy and 133 with osteoporosis) was measured using single X-ray absorptiometry (SXA). A reference range of calcaneus BMD values for healthy Japanese women was established and the usefulness of this method for screening and diagnosis of osteoporosis was evaluated. There was no significant age change of calcaneus BMD prior to menopause, though values decreased significantly thereafter. BMD loss ratio was 1.7%/year in the 10 years after menopause. The reference range of calcaneus BMD was 410 +/- 43 mg/cm(2), calculated from the mean BMD value of subjects whose ages ranged from 25 to 50 years old. The fracture threshold for the spine was established as 294 mg/cm(2), which corresponded to -2.67 SD from the average BMD of the young healthy women, and the odds ratio for spine fracture in the subjects with BMD lower than this threshold was 3.52 [95% CI (confidence interval) 1.34-9.26]. The spine fracture group showed statistically lower calcaneus BMD than the nonfracture group when subjects with adjusted age and body size were analyzed. There were no significant differences in the ROC analysis for spine fracture between calcaneus BMD and spine BMD. Therefore, calcaneus BMD is not readily affected by degenerative change or soft tissue, and the annual decrement rate (1.7%/year) can be detected easily and with low precision error (0.8%). These indices may prove useful for the screening and diagnosis of osteoporosis.

We conclude that calcaneus BMD reflects the L-ADL of RA patients very well and allows us to perform the same level of BMD evaluation as that with current BMD measurement methods.

We developed rickets and osteomalacia in rats by means of a low phosphorus, normal calcium and normal vitamin D diet, causing severely inhibited mineralization. The concentrations of gammacarboxyglutamic acid (Gla) in 10% formic acid and 5M guanidine extracts were studied in normal and phosphate-deficient rat bone. Although the Gla concentration in the formic acid extract was constant for both groups, it decreased in the guanidine extract of the phosphate-deficient group. The Gla content of the guanidine extract reflected a lower concentration of Gla-containing proteins, one of which, matrix Gla protein (MGP), acts as a mineral deposition inhibitor. Thus, the production of MGP decreased in the impaired mineralization of bone. The quantification of Gla in formic acid and guanidine extract is useful in studying the Gla-containing proteins, osteocalcin and MGP.