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Biomedical subjects

J Aoki

Publications and source records attributed to J Aoki.

At least 181 records · Page 10Linked to original sources
PubMed1989

[Urinary calcium excretion in toxemia of pregnancy].

The amount of urinary calcium excretion is an useful marker for distinction between patient with preeclampsia and normal pregnancy of chronic hypertension has been reported. This study was performed to investigate the extent and the etiology of decrease in urinary calcium excretion in toxemia of pregnancy. The subjects in this study were 20 patients with severe toxemia of pregnancy (group T) and 20 subjects with normal pregnancy (group N). In these subjects, serum calcium (s-Ca), phosphate (s-Pi) and uric acid (s-UA) and urinary calcium (u-Ca), phosphate (u-Pi) and uric acid (u-UA) were measured. The values of u-Ca and u-Pi in the group T were significantly decreased than the group N (p less than 0.001, p less than 0.01). The values of s-Ca and s-Pi made no distinction between group T and group N. There was significant relationships between u-Ca and, s-UA (r = -0.70), clearance of UA (r-0.82), Ccr (r = 0.64), and FEca: Cca/Ccr (r = 0.87). These results indicated that the decrease of u-Ca was evident in severe toxemia of pregnancy. And the decrease of u-Ca has resulted from increase of tubular reabsorption. The change of u-Ca of patients with toxemia was studied. After the onset of toxemia, u-Ca was decreased rapidly (less than 50 mg/day) and u-Ca was restored to the normal range (more than 100 mg/day) promptly after delivery. The value of u-Ca was over 100 mg/day in the second pregnancy that developed on toxemia of pregnancy among the cases who has severe toxemia in the first pregnancy. However, toxemia of pregnancy have relapsed in the case with low u-Ca excretion of less than 100 mg/day during the second pregnancy.

Calcium↗
PubMed1988

Osteoclast-mediated osteolysis in bone metastasis from renal cell carcinoma.

Osteolytic characteristics of bone metastasis from renal cell carcinoma were morphologically and biochemically investigated. First, undecalcified ground sections of bone metastases were made from four patients with renal cell carcinoma. Second, renal cell carcinoma cell line (RCC-K1) was established from one of the four patients, and its effect on bone resorption in vitro was examined. Marked proliferation and activation of osteoclasts around the tumor cells was histologically demonstrated. Conditioned medium from the RCC-K1 cells contained potent bone-resorbing activity in vitro. The activity was reduced to basal level by calcitonin, but was not blocked by indomethacin. The activity was lost after dialysis (MW cutoff 3500), while it was retained after 2 weeks of storage. Levels of prostaglandin E2 and 1,25-dihydroxyvitamin D of the RCC-K1-conditioned medium were insufficient to cause bone resorption in vitro. The conditioned medium did not stimulate cAMP accumulation in rat osteoblastic cells. These results suggest that renal cell carcinoma causes bone destruction through the stimulation of osteoclasts by locally secreting an unknown humoral factor or factors.

Aged↗
PubMed1988

Chondroblastoma of the patella.

This study reviews 16 cases of chondroblastoma of the patella which constitute nearly 6% of a large group of chondroblastomas scattered throughout the skeleton. Both radiologic and histologic appearances of chondroblastomas of the patella are indistinguishable from those of chondroblastomas arising in other sites. A reasonable differential diagnosis, including chondromalacia patella, is discussed together with important therapeutic considerations.

Bone Neoplasms↗
PubMed1988

Fluctuations in peripheral serum testosterone levels within a day, with age and by sexual stimulation in male beagle dogs bred indoors.

Fluctuations in serum levels of testosterone (T) within a day, both with age and as a result of sexual stimulation, were examined in male beagle dogs. Eighty male dogs aged between 3 months and 16 years and bred in our laboratory were used under strictly controlled breeding conditions (temperature: 22 +/- 1 degree C, relative humidity: 55 +/- 5%, lighting time: 8:00 a.m.-8:00 p.m.). The level of T was measured by an RIA method. In order to examine the fluctuation in T level within a day, blood samples were obtained at 0:00, 6:00, 12:00 and 18:00 in each of five dogs aged 1.7 and 2.1 years. T levels fluctuated with a regular pattern that was lowest at 12:00, and increased to a peak at 18:00-6:00, thereafter decreasing until 12:00. In order to examine the change in T level with age, blood samples were obtained at 9:00, 12:00 and 16:00 from 70 dogs aged between 3 months and 16 years. The regular diurnal pattern of T level was usually seen, and the levels at 12:00 were always low and did not fluctuate at any age except for 6 months, and 13, 14 and 16 years. The T level at 9:00 increased to reach a peak at 4 years, whereas that at 16:00 did so at 2 years. T levels at 9:00 were significantly higher at 4-12 and 14 years than at 3 months, and were higher at 4 years than at 9 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1987

Reactive endosteal bone formation.

The microstructure of reactive endosteal new bone was examined using undecalcified ground sections in five pathologic conditions (bone metastasis from prostate cancer in seven cases, intervertebral osteochondrosis in five, Paget disease in four, chronic suppurative osteomyelitis in two, and fracture healing in one). To determine a basic form of rapid intramembranous bone formation, fetal rat calvaria and primitive bones made in clonal osteogenic cell culture were also observed. In slow bone-forming conditions, lamellar new bone was deposited on pre-existing trabecular surface and caused trabecular thickening on radiographs. In contrast, in rapid bone-forming conditions, woven bone was deposited as spicules extending from trabecular surface so as to form new networks in intertrabecular space. This causes obscurity of trabecular margins radiographically. Reactive endosteal bone formation may be nonspecific and have a significance for assessing the virulence of underlying pathologic conditions like periosteal reactions.

Aged↗
PubMed1987

End plate of the discovertebral joint: degenerative change in the elderly adult.

Degenerative change at the end plate of the discovertebral joint was studied in the elderly adult by correlating the histologic and radiographic findings. Undecalcified ground sections were made from 21 autopsied lumbar spines that demonstrated no evidence of disease except age-related osteoporosis. Histologic examination showed that the cartilaginous end plates were degenerated to various extents and were replaced by subchondral bone proliferation (endochondral bone formation) in the direction of the joint space. In advanced cases, this histologic finding was reflected in radiographs as a subchondral sclerotic zone protruding toward the disk space. The degree of end-plate change was positively correlated with disk-space narrowing and the vacuum phenomenon (degeneration of the nucleus pulposus) but not with osteoporosis and vertebral compression. Anatomically and functionally, this may be the most common form of degeneration at the discovertebral joint end plate. Further study will be necessary to clarify the process.

Aged↗
PubMed1987

Circulating 1,25-dihydroxyvitamin D concentrations in patients with renal cell carcinoma-associated hypercalcemia are rarely suppressed.

We measured serum 1,25-dihydroxyvitamin D concentrations in 18 patients with renal cell carcinoma-associated hypercalcemia. Only 2 patients (11%) had low serum 1,25-dihydroxyvitamin D (less than 15 pg/ml) levels, and the mean 1,25-dihydroxyvitamin D level in the 18 patients was 44 +/- 30 (+/- SD) pg/ml, not different from the value of 42 +/- 22 pg/ml in 75 age-matched normocalcemic patients with various malignancies. Eighty-seven percent (26 of 30) of the hypercalcemic patients with extensive skeletal metastases due to other malignancies or with hematological malignancies had suppressed serum 1,25-dihydroxyvitamin D levels (less than 15 pg/ml). In hypercalcemic patients with other malignancies and no skeletal metastases, only 54% (21 of 39) had low serum 1,25-dihydroxyvitamin D levels. The mean serum 1,25-dihydroxyvitamin D level in the latter group was 21 +/- 26 pg/ml, significantly lower than that in normocalcemic patients. In renal cell carcinoma-associated hypercalcemia, suppression of circulating 1,25-dihydroxyvitamin D concentrations is uncommon.

Adult↗
PubMed1987

Co-purification of bone resorbing activity and adenylate cyclase stimulating activity from human tumours associated with the humoral hypercalcaemia of malignancy.

We have partially purified a tumour factor capable of stimulating both bone resorption in vitro and cAMP accumulation in osteoblastic ROS 17/2 cells from three human tumours associated with humoral hypercalcaemia of malignancy. Purification of tumour factor by sequential acid urea extraction, gel filtration and cation-exchange chromatography, reverse-phase high performance liquid chromatography followed by analytical isoelectric focussing provided a basic protein (pI greater than 9.3) with a molecular weight of approximately 13,000 as a major component of the final preparation which retained both the two bioactivities. Bone resorbing activity and cAMP-increasing activity in purified factor correlated with each other. cAMP-increasing activity of the factor was heat- and acid-stable, but sensitive to alkaline ambient pH. Treatment with trypsin destroyed cAMP-increasing activity of the factor. Synthetic parathyroid hormone (PTH) antagonist, human PTH-(3-34) completely inhibited the cAMP-increasing activity of the factor. The results suggest that this protein factor, having its effects on both osteoclastic and osteoblastic functions, may be involved in development of enhanced bone resorption in some patients with humoral hypercalcaemia of malignancy.

Adenylyl Cyclases↗
PubMed1986

[Aluminum associated bone disease in patients undergoing long-term hemodialysis].

The widespread clinical use of hemodialysis has prolonged the survival of a vast number of uremic patients, but it has also yielded some problems including renal osteodystrophy. Recently, it has become well known that the clinical use of active vitamin D metabolites is effective in many patients with renal osteodystrophy. However, there are many patients with bone diseases resistant to such treatment. Several lines of evidences implicate aluminum as one of the causal factors in the production of such diseases. We recently found 20 patients with bone diseases associated with the deposition of aluminum in front of active calcification in the bone. All of them were undergoing maintenance hemodialysis with softened water thrice weekly and taking aluminum containing antacids and 1 alpha-(OH)D3. The age of the patients ranged between 30 y.o. and 62 y.o. (46.5 +/- 9.0, mean +/- s.d.). All of them had severe bone pain and 8 of them had bone fractures. Bone X-ray, bone scintigraphy, serum Ca, P, ALP, serum aluminum and bone histology were examined. Based on the bone histology, they were classified into four types; inactive type (9), osteomalacia type (6), mild type (4) and mixed type (1). There were no significant differences among each group concerning serum values of Ca, P and aluminum. Serum value of ALP tended to be high in the osteomalacia type, and that of c-PTH was significantly low in the inactive type compared with the other types. Our finding suggest that aluminum associated bone disease is not so rare in Japan and show that the diagnosis of this disease should be made histologically and that clinical and blood chemical features are not reliable for the diagnosis of aluminum associated bone disease in hemodialysis patients.

Adult↗
PubMed1986

Human calcitonin gene-related peptide possesses weak inhibitory potency of bone resorption in vitro.

Synthetic human calcitonin gene-related peptide (CGRP) was examined for the action on the bone in vitro. Human CGRP inhibited bone resorption stimulated by both human parathyroid hormone and basal. The mode of inhibitory action of human CGRP seemed to be similar to that of calcitonin and the relative potency of human CGRP to inhibit bone resorption is one five-hundredth of that of human calcitonin. Thus, a novel pharmacological action of CGRP was demonstrated.

Animals↗
PubMed1986

Evidence that factors other than 1,25 dihydroxyvitamin D may play a role in augmenting intestinal calcium absorption in patients with primary hyperparathyroidism.

We examined 17 patients with primary hyperparathyroidism for their serum 1,25 dihydroxyvitamin D levels and for their fractional intestinal calcium absorption rates using a whole body counter and calcium-47. As controls, 10 normal volunteers were examined both before and after administration of 1 alpha-hydroxyvitamin D to increase serum 1,25 dihydroxyvitamin D. Values of serum 1,25 dihydroxyvitamin D were 71.6 +/- 37.6 pg/ml (mean +/- SD) in patients with primary hyperparathyroidism and 75.3 +/- 27.7 pg/ml (mean +/- SD) in normal volunteers after administration of 1 alpha-hydroxyvitamin D, while values of intestinal calcium absorption rate were 61.5 +/- 16.5% (mean +/- SD) in patients with primary hyperparathyroidism and 34.1 +/- 5.1% (mean +/- SD) in normal controls, respectively. There was a positive correlation between values of serum 1,25 dihydroxyvitamin D and intestinal calcium absorption in both groups. However, in patients with primary hyperparathyroidism, intestinal calcium absorption was more increased than that in normal volunteers when compared to their serum values of 1,25 dihydroxyvitamin D. This suggests that another factor than 1,25 dihydroxyvitamin D plays an important role in the intestinal calcium absorption in patients with primary hyperparathyroidism.

Adult↗