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Biomedical subjects

M Ohmori

Publications and source records attributed to M Ohmori.

At least 217 records · Page 12Linked to original sources
PubMed1984

Synergistic activity of astromicin and beta-lactam antibiotics against Pseudomonas aeruginosa in vitro and in vivo.

Synergistic activity of astromicin and an antipseudomonal beta-lactam antibiotic such as piperacillin, cefsulodin or carbenicillin against Pseudomonas aeruginosa was demonstrated in vitro and in vivo. Synergy in vitro was observed more often when astromicin was combined with piperacillin or cefsulodin than when it was combined with carbenicillin. The combination of astromicin with piperacillin showed a bactericidal activity against Pseudomonas aeruginosa at a bacteriostatic concentration of each antibiotic alone. The synergy observed in vitro was reproduced against experimental mouse infections, and the astromicin-piperacillin or cefsulodin combination produced significantly greater protective effects than the single use of individual antibiotics.

Aminoglycosides↗
PubMed1984

Sodium fluoride-induced morphological and neoplastic transformation, chromosome aberrations, sister chromatid exchanges, and unscheduled DNA synthesis in cultured syrian hamster embryo cells.

The effects of exposure of early-passage Syrian hamster embryo cells in culture to sodium fluoride have been studied with respect to induction of morphological and neoplastic transformation, chromosome aberrations, sister chromatid exchanges, and unscheduled DNA synthesis. Exposure of Syrian hamster embryo cells to NaF concentrations between 75 and 125 micrograms/ml for 24 hr caused approximately 90 to 40% cell survival and resulted in a dose-dependent increase in the frequency of morphological transformation of the cells. Mass cultures of cells treated with NaF (75 or 100 micrograms/ml) for 24 hr, followed by continuous cultivation for 35 to 50 passages, developed the ability to grow in soft agar and to produce anaplastic fibrosarcomas when injected into newborn hamsters. In contrast, no morphological and neoplastic transformation was observed in untreated cells. Furthermore, a significant increase in chromosome aberrations at the chromatid level, sister chromatid exchanges, and unscheduled DNA synthesis was induced by NaF in a dose- and time-dependent manner. These results indicate that NaF is genotoxic and capable of inducing neoplastic transformation of Syrian hamster embryo cells in culture. A potential for carcinogenicity of this chemical, which is widely used by humans, is suggested. However, the carcinogenic risk of this chemical to humans may be reduced by factors regulating in vivo dose levels.

Animals↗
PubMed1984

[A case of hyperthyroidism combined with thyroid carcinoma].

A 33-year-old woman, with hyperthyroidism combined with thyroid carcinoma is presented. She was given antithyroid medication before the operation, and sub-total thyroidectomy was performed under local anesthesia. Her postoperative course was smooth. Histologically, the resected thyroid was shown to have two small nodular lesions of papillary carcinoma in the diffuse goiter. The current classification, statistics, diagnosis and therapy of this disease are discussed.

Adenocarcinoma, Papillary↗
PubMed1983

Isolation and identification of 1 alpha- and 23-hydroxylated metabolites of 25-hydroxy-24-oxovitamin D3 from in vitro incubates of chick kidney homogenates.

Five major metabolites (peaks I-V) of 25-hydroxy-24-oxovitamin D3 (25(OH)24-oxo-D3) have been isolated in pure form from in vitro incubates containing kidney homogenates of vitamin D-deficient chicks and chicks given 65 nmol of vitamin D3; peaks II, III, and V are from vitamin D-deficient chicks and peaks I, II, and IV are from vitamin D-supplemented birds. The structures of the metabolites were unequivocally identified as 23,25-dihydroxy-24-oxo-vitamin D3 (peak I), 24,25-dihydroxyvitamin D3 (24,25(OH)2D3) (peak II), 1 alpha, 25-dihydroxy-24-oxovitamin D3 (peak III), 23,24,25-trihydroxyvitamin D3 (peak IV), and 1 alpha,24,25-trihydroxyvitamin D3 (peak V) by means of ultraviolet absorption spectrometry, mass spectrometry, and specific chemical reactions. It is concluded that 25(OH)24-oxo-D3 is further hydroxylated at the 1 alpha-position in the kidney of vitamin D-deficient chicks and at the 23-position in that of vitamin D-supplemented animals. Formation of 24,25(OH)2D3 from 25(OH)24-oxo-D3 in both vitamin D-deficient and -supplemented animals provides evidence for the presence of an enzyme to reduce the 24-oxo group irrespective of the vitamin D status.

Animals↗
PubMed1983

Biological activity of 24,24-difluoro-1 alpha, 25-dihydroxyvitamin D3 and 1 alpha, 25-dihydroxyvitamin D3-26,23-lactone in inducing differentiation of human myeloid leukemia cells.

Vitamin D compounds added to the culture medium induce differentiation of human myeloid leukemia cells (HL-60 cells) by binding to a specific cytosol receptor protein. This system provides a biologically relevant and technically simple assay to examine the relationship between molecular structure and biological activity of vitamin D compounds. Using this culture system, the biological activity of 24,24-F2-1 alpha,25(OH)2D3 and 1 alpha,25(OH)2D3-26,23-lactone was assayed. 24,24-F2-1 alpha,25(OH)2D3 was four to seven times more potent than 1 alpha,25(OH)2D3 in inducing phagocytosis and C3 rosette formation of HL-60 cells, though both compounds bound equally well to the cytosol receptor, suggesting that the defuorination at the 24-carbon position may stimulate membrane permeability of the compound. 1 alpha,25(OH)2D3-26,23-lactone, on the other hand, was only 1/200th as active as 1 alpha,25(OH)2D3. The binding affinity of the lactone for the cytosol receptor was identical with that of 1 alpha (OH)D3, suggesting that the lactone formation between the 26 and 23 positions masks the function of the 25-hydroxyl group. The binding affinity of vitamin D3 derivatives to the specific cytosol receptor of HL-60 cells was well correlated with that of intestinal cytosol protein specifically bound to 1 alpha,25(OH)2D3.

Calcitriol↗
PubMed1983

Primary adenocarcinoma of the renal pelvis. Report of two cases and brief review of literature.

Two cases of primary adenocarcinoma of the renal pelvis are described. One patient was a 64-year-old female who had multiple papillary tumors in the right ureter and renal pelvis. The other was a 57-year-old male who had diffuse infiltrating carcinoma in the left renal pelvis with calculi. In both cases, the lining of the renal pelvis underwent columnar cell metaplasia and the tumor cells showed mucin production. Forty-six cases reported previously are reviewed briefly. The histogenesis of primary adenocarcinoma of the renal pelvis seems to be closely related to metaplasia of transitional epithelium induced by longstanding chronic inflammation or renal calculi in many cases.

Adenocarcinoma↗
PubMed1982

Chemical synthesis, biological activity, and metabolism of 25-hydroxy-24-oxovitamin D3.

25-Hydroxy-24-oxovitamin D3 (25(OH)24-oxo-D3), a metabolite of 25-hydroxyvitamin D3, has been chemically synthesized. The ultraviolet, mass, infrared, and proton nuclear magnetic resonance spectra of the 25(OH)24-oxo-D3 were identical with those of the natural product isolated from chick kidney incubates. The oxo compound showed biological activity similar to 24,25-dihydroxyvitamin D3 (24,25(OH)2D3) in vitamin D-deficient chicks in enhancing intestinal calcium transport and bone calcium mobilization activities. Although 25(OH)24-oxo-D3 partially restored the impaired eggshell weights of Japanese quails fed a vitamin D-deficient diet, it was much less potent than 25-hydroxyvitamin D3 or 1 alpha, 25-dihydroxyvitamin D3. In addition, there was no effect on the calcification of medullary bone. When 25(OH)24-oxo[3H]D3 was incubated with kidney homogenates from vitamin D-deficient chicks, it was metabolized to [3H]1 alpha, 24,25-trihydroxyvitamin D3 and a metabolite which was eluted in a region between authentic 24R,25(OH)2D3 and 1 alpha, 25-dihydroxyvitamin D3 on high pressure liquid chromatography. In the incubates of kidney homogenates from vitamin D-supplemented chicks, those metabolites were not detected. In vitamin D-supplemented chicks, the recovery of radioactivity in the chloroform phase extracted by the method of Bligh and Dyer was only 50%, while that in vitamin D-deficient chicks was 87%. Moreover, the radioactivity eluted in the 25(OH)24-oxo-D3 fraction from vitamin D-supplemented chicks was only one-fifth of that from vitamin D-deficient birds. The present results indicate that the 24-oxidation of 24,25(OH)2D3 may be a route of inactivation of vitamin D3.

Animals↗
PubMed1982

The sympathetic hazards of airborne ultrasound on ultrasound sensitive mice.

A commercially available ultrasonic equipment (55-50 kHz/sec, 425 W) operated at a distance of 4 m air space caused death in some mice. The physical energy propagated was quite small, being calculated at less than 0.21 W/cm2. Among many strains of mice, the RIII strain was especially sensitive to ultrasound, and the peak of sensitivity was at 3 to 4 weeks of age at which the mortality rate was 95/149 (64%). No death occurred when mice were pretreated by (a) removing all body hair, (b) by administration of morphine hydrochloridum with a tail reaction, and (c) administration of a sympathetic blocking agent. From these results it is assumed that the ultrasound energy absorbed by the body fur reaches the hypothalamus through the sensory nerves of the hair roots. After the hypothalamus where central sympathetic nerve functions are localized, the stimulus passes down the descending tract of the sympathetic nerve, reaching the cardiac nerves via the autonomic nerve ganglion. Thus, death could occur by shock of the sympathetic nerve reflex.

Air↗
PubMed1982

Malignant hyperthermia.

A report is made of a 65-year-old male who died of a malignant hyperthermia of 42 degrees C. Symptoms included muscle rigidity at the termination of operation for neck-clipping of an aneurysm of the anterior communicating artery. Latent myopathy was observed in skeletal muscle, and a bleeding focus was present in the left anterior region of the hypothalamus, coinciding with the temperature regulation center. The mechanism of onset of this disease is still poorly understood, but it seems that this disease occurred due to synergic effects of the hypothalamic hemorrhage and the pre-existing myopathy. The serum CPK level at the time of death was abnormally high (250 U), and 3.4% of isozyme CPK1 was detected. The serum myoglobin was 204, 850 ng/ml, a markedly high level, and myoglobinuric nephrosis was present as a result.

Aged↗
PubMed1981

An examination of the importance of 24-hydroxylation to the function of vitamin D during early development.

To investigate the biological importance of 24R-hydroxylation of 25-hydroxyvitamin D to the early development of rats, the potency of 24,24-difluoro-25-hydroxyvitamin D3 had been compared to that of 25-hydroxyvitamin D3 in young rat pups born to vitamin D-deficient mothers. 24,24-Difluoro-25-hydroxyvitamin D3 and 25-hydroxyvitamin D3 were equally active in stimulating active calcium transport in the intestine, maintaining normal concentrations of calcium and phosphorus in the plasma and promoting bone growth and mineralization. These results provide strong evidence that the presence of a hydroxyl group at the 24 position of vitamin D3 is not required for the maintenance of calcium-phosphate homeostasis during growth and in the development and mineralization of bone.

Animals↗