To test the effect of amino-terminal peptide 1-34 of human parathyroid hormone (hPTH (1-34)) as a possible bone anabolic agent in the treatment of osteoporosis, weekly subcutaneous injection of 50 units (L group), 100 units (M group) or 200 units (H group) of hPTH (1-34) was started in 220 patients with osteoporosis at 71 institutions randomly divided into three groups in a double-masked system. Lumbar spine bone mineral density (BMD) by dual-energy X-ray absorptiometry (DXA) increased by 0.6%, 3.6% and 8.1% after 48 weeks in groups L, M and H respectively, responses in groups M and H being significantly higher than in L (p<0.05, Mann-Whitney U-test). Since the coefficient of variation for lumbar spine measurement stayed at 1-2.5%, increases of 3.6% and 8.1% appeared significant. Metacarpal BMD and cortical thickness measured by radiogrammetry did not change significantly. Serum calcium decreased in each group and serum phosphorus decreased in groups M and H. Urinary calcium/creatinine decreased at the 12th week in group H and at the 24th and 48th weeks in groups M and L. Serum 25(OH) vitamin D and 1,25(OH)(2) vitamin D decreased in each group at the 48th week (p<0.05). Serum bone-type alkaline phosphatase was increased at the fourth week in groups H and M and decreased at the 48th week in group H. Urinary hydroxyproline, pyridinoline and deoxypyridinoline declined significantly in each group. Backache improved in 30-40% of each group. No serious adverse effects were found during the test period. Intermittent weekly injection of hPTH (1-34) increased lumbar BMD in osteoporosis, suggesting usefulness in the treatment of osteoporosis.

Structural analysis of bones is now actively studied by many researchers using the finite-element method (FEM) to better understand the mechanism of bone fractures. Most previous studies, however, only obtained distribution patterns of stress or strain, and did not show how a fracture initiates and proceeds or how a fracture line grows. The purpose of this study was to simulate a fracture procedure using FEM and to assess its usefulness. Correlation of the strain value of the simulation and of the experiment was satisfactory (r = .81). The simulated fracture process and the consequent fracture lines were quite compatible with the experimental fracture. Quantitatively, however, there was a difference of yield load between the simulation and the experiment, i.e., 2000N and 8400N, respectively, likely caused by inaccuracies of material properties of the elements of the finite-element model.

The study suggested that bone fragility induced by single fractional irradiation doses (given once daily up to high cumulative doses) was not associated with change in the cortical BMC. It also confirmed the preference for twice-daily fractional irradiation as compared to once-daily fractional irradiation and the total single dose.

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