Hideyuki Aratani

Altered calcium homeostasis accompanying changes of regional bone mineral during a very-low-calorie diet.

Calcium homeostasis during a very-low-calorie diet (VLCD) was examined. During the treatment, intact parathyroid hormone tended to decrease initially, bone Gla-protein increased significantly in the third week, and tartrate-resistant acid phosphatase decreased during the entire treatment. Serum ketone bodies showed significant correlations with intact parathyroid hormone and bone Gla-protein in some cases. Regarding bone mineral content, bone mineral content of the head increased while that of the legs decreased, resulting in no significant changes in total bone mineral content. These results suggest that VLCD treatment alters calcium homeostasis, which may cause regional bone mineral changes.

High-density-lipoprotein metabolism during a very-low-calorie diet.

We examined the changes in high-density-lipoprotein (HDL) metabolism in eight female obese patients undergoing a very-low-calorie diet (VLCD). In the first half of the study, HDL cholesterol (HDL-C), apolipoprotein A-I (apo A-I), and apo A-II showed a parallel decrease. Although lipoprotein lipase (LPL) and hepatic lipase (HTGL) did not change, lecithin: cholesterol acyltransferase (LCAT) decreased. In the latter half of the protocol, HDL-C and apo A-I increased whereas apo A-II decreased, resulting in increased apo A-I-A-II ratios. There was no change in LPL, HTGL, or LCAT. LCAT and apolipoprotein composition may be important in HDL-C changes after VLCD.

Efficacy of low-dose, intermittent eel calcitonin treatment for osteoporosis

The efficacy of low-dose intermittent calcitonin treatment for osteoporosis was evaluated. Twenty subjects (19 women, 1 man, mean age 59.1 ± 8.1) who exhibited osteopenia on plain X-ray were treated once a week with either a 10-IU or 20-IU i.m. injection of eel calcitonin (Elcatonin). Bone mineral density (BMD) of the lumbar spine as determined by dual photon absorptiometry significantly increased in the 20-IU group at 3 (7.2%) and 6 (10.7%) months, while the results were not significant in the 10-IU group (2.0% and 2.4%, respectively). Forearm BMD assessed by single photon absorptiometry did not change significantly in either group. The urinary hydroxyproline/creatinine ratio was significantly suppressed in both groups (P < 0.05). Serum bone Gla-protein showed a tendency to increase at 6 months in both groups. Spontaneous back pain disappeared by the end of this study in all patients who received 20IU per week, although it persisted in some of the patients in the 10-IU group. These results suggest that low-dose, intermittent calcitonin is effective at least after 6 months in the treatment of osteoporosis with a minimum dose of calcitonin at 20IU per week.

Total body and regional bone mineral content in hemodialysis patients

Bone mineral content (BMC) in the total body and lumbar spine was evaluated in 126 hemodialysis patients (60 males, 66 females) by dual photon absorptiometry with the Norland DBD 2600. Measurements of: 1) total body BMC divided by lean body mass (BMCTB/LBM), 2) bone mineral density (BMD) of total body, 3) BMD of four regional sections (head, trunk, pelvis, and legs), and 4) BMD of lumbar spine, generally showed a significant decrease in the hemodialysis patients compared to the reference population. However, arm BMD did not show a significant difference between patients and control populations. The z-score of BMCTB/LBM declined significantly throughout the duration of hemodialysis, although that of the lumbar spine BMD did not. It should be noted that the degree of decrease in BMC was more prominent in the total body measurement than in the lumbar spine measurement. There was preferential osteopenia of the total body in the hemodialysis patients. Although the lumbar spine BMD showed a lower value than the control population, the lumbar spine is not the recommended region to monitor the BMD change in hemodialysis patients.

Effect of ipriflavone on bone mineral density of lumbar spine of aged women

Aged women with osteoporosis were followed for 6 months with or without ipriflavone (IP) 600 mg/day, and lumbar bone mineral density (BMD) and bone mineral content (BMC) were evaluated by dual-photon absorptiometry. Although a significant reduction of lumbar BMD was observed in the control group at the end of the experiment, the group treated with IP showed insignificant change. The frequency of deterioration was lower in the IP group compared to the control group. Additionally, the IP effect was more apparent in patients with lower calcitonin and higher bone gla-protein (BGP) levels. These results suggest that IP effectively maintains BMD and BMC of lumbar bone among aged women with osteoporosis, and its activity may be enhanced in patients with low calcitonin and high BGP levels.