We evaluated the severity of various kinds of experimental osteoporosis in rats by photomicrodensitometry using soft x-ray film, with emphasis on the effect of immobilization combined with ovariectomy and low-calcium diet. Since the values obtained by photo-microdensitometry were correlated well with ash weight of the femora, photo-microdensitometry appears to be a useful method for evaluating the degree of experimental osteoporosis. The severity of osteoporotic changes depended on the extent of immobilization. The changes after ovariectomy combined with immobilization as well as low-calcium diet combined with immobilization were more pronounced than after each procedure alone, suggesting a synergistic effect.

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Changes of serum bone Gla protein (BGP) were followed along with serum calcium and parathyroid hormone (PTH) on administration of salmon calcitonin (SCT) in patients with primary hyperparathyroidism (PHP). Intramuscular administration of 80 units of SCT in 12 patients with PHP resulted in a significant fall of serum Ca from 30 minutes after the injection, reaching the lowest value 3-12 hours later, and returned to the pre-administration level 24 hours later. Serum PTH showed a tendency of rise after CT administration reaching a significantly higher level 12 hours later. Serum BGP showed a significant decrease 3-12 hours, returning the previous level 24 hours later. After SCT administration, a significant positive correlation was noted between the maximum fall of serum BGP and preadministration serum BGP values. On intramuscular injection of 40 units SCT morning and evening on 7 consecutive days in 4 patients with PHP, both serum Ca and BGP tended to decrease during the initial period of administration, but the effect fell of within a few days.
Thus, SCT directly inhibits the enhanced bone resorption in patients with PHP. Also, a possibility exists that SCT may exert a direct or indirect inhibitory action on enhanced bone formation.

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Calcitonin preparations have recently been introduced in clinical therapeutics for various metabolic bone diseases, especially osteoporosis. While the analgesic effect of calcitonins on lumbago and backache in osteoporosis has been well recognized, scarecely any detailed reports are yet available as to the effect of calcitonins on osteopenia, the main bone manifestation of osteoporosis.
In the present study, 10 units, [Asu^{1, 7}]-Eel calcitonin (Elcatonin), a synthetic derivative of eel calcitonin, was injected intramuscularly at 2-4 day intervals over a period of 3-12 months. Patients with osteoporosis were divided into two groups according to the serum calcium value at the beginning of treatment, those with serum calcium 9.0mg/dl, to evaluate the effect of Elcatonin on blood biochemical data and bone mass. Bone mass kept decreasing in osteoporosis with serum calcium <9.0mg/dl despite Elcatonin treatment, whereas bone mass kept unchanged in the group with serum calcium ≥9.0mg/dl, suggesting the importance of initial serum calcium level in predicting the effect of Elcatonin on bone mass.

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Histological findings of undecalcified bone specimens obtained from five patients with Paget's disease of bone are presented comparing with the features of bone x-ray and bone scintigraphy.
X-ray films showed pure osteolysis in one, combined lesions with osteosclerosis and osteolysis in three, and dominant osteosclerosis in one. Bone scintigraphy showed intensively increased uptakes of Tc-99m in all lesions.
The characteristic findings of histological sections were giant polynuclear osteoclasts, active osteoblasts, increase of osteoid, acceleration of calcification, mosaic pattern of trabecular bone, fibrosis of bone marrow and porliferation of blood vessels. Comparing with the x-ray findings, histological sections showed dominant bone resorption in the case of lytic stage, acceleration of bone turnover in the cases of combined stage and dominant bone formation in the case of sclerotic stage. These findings were confirmed quantitatively by histomorphometry.
Administration of EHDP improved both clinical symptoms and blood-chemical data. The histological examination revealed active bone resorption and formation prior to treatmen and marked decrease of osteoclasts and osteoblasts with improvement of bone marrow fibrosis after treatment.

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The regional Specificities of bone metabolism were studied by multidimensional scaling in 95 postmenopausal women aged 54-91 years (mean±standard deviation, 72.7±8.08 years). The degree of osteoporosis of proximal femurs was assessed according to the Singh index. Radiographs of lumbar region of the spine were used for assessing the spinal score of osteoporosis according to the modified method of Itami and O'hata. The metacarpal index was used to quantify osteoporosis of the hand. Kendall correlation coefficient was calculated between any ratings of the three indexes of osteoporosis, We analysed the three correlation coefficients with the theory of quantification (IV) by Hayashi which is one method of multidimensional scaling and with another method of the principal co-ordinate analysis by Gower. The relation among the three ratings of bone mass (Singh index, spinal score, metacarpal index) was equi-distant in the two dimensional geometry, precluding the use of metacarpal index or Singh index instead of spinal score. In order to assess the degree of osteoporosis of the spine, we have to estimate it from the spine itself.

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In ovo and in vitro effects of hydrocortisone on the changes of bone γ-carboxyglutamic acid-containing protein (BGP), alkaline phosphatase activity and mineral composition were studied in developing chick embryo. Administration of hydrocortisone into developing chick embryo in ovo retarded the growth of the femur, decreased alkaline phosphatase activity of bone origin in serum, deranged the bone mineral composition and decreased bone and serum BGP levels. The addition of hydrocortisone in the culture medium of chick embryonic calvaria in vitro at concentrations of 1 and 10μM also decreased bone BGP level. When added at concentrations of 0.1-10μM, hydrocortisone decreased BGP level in the culture medium significantly.
These results suggest that hydrocortisone appears to act on osteoblasts to decrease the synthesis and secretion of BGP, consequently changing the bone mineral composition.

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Age-associated bone changes in the Senescence-Accelerated Mouse (SAM)-P/6/Ta and its control, SAM-/1/Ta reared under specific pathogen-free (SPF) conditions were examined. Morpometric analysis of the femurs in 3- and 5-month-old SAM-P/6/Ta revealed obvious reduction of bone volume as evidenced by a decreased cortical area and an increased marrow area in the mid-shaft compared with those in SAM-R/1/Ta of the same ages. Chemical analysis of the femurs showed a decrease in hydroxyproline content in SAM-P/6/Ta at 3 and 5 months of age. The femoral calcium content was varied with age. The body weight of SAM-P/6/Ta tended to be increased at 5 months and was significantly increased at 7 months; thus increase in body weight was associated with a significant increase in the weight of the epididymal fat pads. The serum insulin level in 5-month-old SAM-P/6/Ta exhibited a tendency to be increased over that of the control. Oral glucose tolerance test conducted at 7 months of age demonstrated a decreased glucose tolerance in the SAM-P/6/Ta.
These results indicate that SPF SAM-P/6/Ta develops the same bone reduction previously reported to occur in conventionally-reared SAM-P/6. However, SPF SAM-P/6/Ta is concluded to be a murine model that is characterized by bone loss, obesity, possible hyperinsulinemia, and glucose intolerance.

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This study was undertaken in an attempt to show the effect of parathyroidectomy on the calcification and ossification processes in the femoral head epiphysis of rats, through the findings obtained by a light microscope, a scanning electron microscope and an energy dispersive X-ray analyzer. A total of 256 wistar rats were used in this experiment. The rate of appearance of ossification centers of parathyroidectomized rats was higher than that of the controls at the age of 84 days (P<0.005). The apatite crystal globules were observed to deposite in the epiphyseal cartilage at the calcification stage and their sizes increased with age. The tendency was found to be slightly accelerated in the parathyroidectomized rats. The ratio of calcium to phosphorus of apatite crystal globules measured by an energy dispersive X-ray analyzer was lower in the parathyroidectomized rats (P<0.01). Earlier completion of calcification may cause higher rate in appearance of ossification centers as a consequence of parathyroidectomy.

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The effects of ipriflavone (TC-80) administered with or without 1α, 25-dihydroxycholecalciferol (DHCC) on morphological and mineral changes in the calvarium have been examined in neonatal rats. DHCC (5-20ng/day/rat), TC-80 (62.5-125μg/day/rat), or both were injected subcutaneously once a day for five days. The morphological changes were evaluated by microensitometry of soft x-ray photographs of the calvarium, and the mineral changes were evaluated by chemical and x-ray powder diffraction methods.
DHCC-treated group had smaller-sized calvaria and wider sutures compared to control gorup as measured by soft x-ray photography. The mineral contents of the asked calvarium, Ca/P ratios in the ash, and x-ray diffraction variables which correspond to hydroxyapatite contents in the ash, were also reduced by DHCC. The addition of TC-80 tended to normalize these variables. The results show that when DHCC is administered to rat pups in the doses used, it demineralizes the calvarium in a dose-dependent manner; the simultaneous administration of TC-80 inhibits the bone changes induced by DHCC.

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