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Biomedical subjects

M Ohmori

Publications and source records attributed to M Ohmori.

At least 199 records · Page 11Linked to original sources
PubMed1988

[An autopsy case of parotid clear cell carcinoma with cerebellar invasion and metastasis to the lung].

An autopsy case of a clear cell carcinoma of the salivary gland with a cerebellum invasion and a metastasis to the lung is reported. This case has been classified as a monomorphic variant, although we were unable to demonstrate the presence of glycogens in the cytoplasm of the tumor cells. Ultrastructurally, most of the proliferating cells were immature cells with few organelles. The tumor cells were unable to be differentiated into ductal cells and myoepithelial cells. Recently, the tumor has been determined to be a low grade malignancy. Obviously, this tumor had a malignant character, with a cerebellum invasion and a metastasis to the lung.

Adenocarcinoma↗
PubMed1988

Myospherulosis in Japan. A report of two cases and an immunohistochemical investigation.

We report two cases of myospherulosis and offer review of the Japanese literature. Case 1 was a 41-year-old woman with cystic tumors under the fascia of the right major gluteal muscle. Case 2 was a 36-year-old man with subcutaneous cystic tumors in the right buttock. The characteristic saccular structures enclosing numerous small spherules were observed in the cysts. These spherules measured 5-7 micron in diameter and stained with Masson trichrome, Giemsa, Papanicolaou, and alizarin red S for hemoglobin. The myospherules also stained positively by the immunohistochemical method for hemoglobin. These findings support the contention that the spherules and parent bodies were derived from erythrocytes altered by foreign lipids or fat.

Adult↗
PubMed1988

[A case of eosinophilic granuloma of the lymph nodes].

A case of eosinophilic granuloma of the lymph nodes is reported. Two finger-tip-sized masses were recognized in the left postauricular region in a 4-month-old female. Both masses had distended peripheral sinuses occupied by proliferating cells with nuclear indentation. These foci were accompanied with a central necrosis and eosinophils that had infiltrated into the dermis, and were observed also in the efferent lymph duct. Immunohistochemically these cells were positive for S 100 beta, OKT 4, and OKT 6, and were weakly positive for S 100 alpha. These findings suggest that proliferating cells in the T-zone histiocyte lineage might have been somewhat different in this case from usual cases of eosinophilic granuloma.

Eosinophilic Granuloma↗
PubMed1987

Phenylalanine dehydrogenase of Bacillus badius. Purification, characterization and gene cloning.

Phenylalanine dehydrogenase produced by Bacillus badius IAM 11059 was purified from the crude extract of B. badius to homogeneity, as judged by disc gel electrophoresis. The enzyme has an isoelectric point of 3.5 and a relative molecular mass, Mr, of 310,000-360,000. The enzyme is composed of identical subunits with an Mr 41,000-42,000. The substrate specificity of the enzyme in the oxidative deamination reaction was high for L-phenylalanine, but rather low in the reductive amination reaction, with phenylpyruvate, p-hydroxyphenylpyruvate, and 2-oxohexanoate. The gene for the enzyme was cloned into Escherichia coli with plasmid pBR322 as a vector. The enzyme was expressed in high level in E. coli. The enzyme produced by E. coli transformant was purified to homogeneity and shown to be identical to that of B. badius IAM 11,059 with respect to the specific activity, Mr, subunit structure and amino acid composition.

Amino Acid Oxidoreductases↗
PubMed1987

Idiopathic nonarteriosclerotic cerebral calcification (Fahr's disease): an electron microscopic study.

A case of idiopathic nonarteriosclerotic cerebral calcification was studied post mortem by histochemical and scanning and transmission electron microscopic methods. Calcification was found bilaterally in the basal ganglia, cerebral cortex, granular layer and white matter of the cerebellum. Histochemical examination revealed that deposits were composed of a mixture of glycoproteins, mucopolysaccharides, calcium salts and iron. Transmission electron microscopy revealed minute deposits mainly in the cytoplasm of adventitial cells of blood vessels and sometimes in the cytoplasmic processes of glial cells. Scanning electron microscopy showed that some of the spherical and hemispherical bodies, which were formed in the adventitial cells of blood vessels, were connected with filamentous cytoplasmic processes of surrounding cells. Small uncalcified deposits occurring in the cytoplasm of the adventitial cells had subsequently had minerals deposited in them. Some kind of impairment of the pericytes may play an important role at the onset of this disease.

Brain↗
PubMed1987

Anaplastic carcinoma of the thyroid with osteoclast-like giant cells. An ultrastructural and immunohistochemical study.

An unusual anaplastic thyroid carcinoma with osteoclast-like giant cells is reported in a 72-year-old woman. Monotonous proliferation of variously sized mononuclear tumor cells interspersed with numerous osteoclast-like multinucleated giant cells was dominant. A small area of papillary carcinoma merging with the anaplastic carcinoma was disclosed. Immunohistochemically, tumor cells forming papillary pattern were positive for both thyroglobulin and keratin. Cells and cell clusters positive for keratin were found in anaplastic carcinoma. Electron microscopically, the anaplastic carcinoma cells displayed prominent mitochondria, a rough endoplasmic reticulum, and intermediate cell junctions. The cell clusters formed irregular lumina into which numerous microvilli were extended and which contained colloid-like material. Occasionally incomplete basal laminae were present. Cell clusters showing transitional pictures from cell clusters to multinucleated giant cells and multinucleated giant cells engulfing mononuclear tumor cells were observed by both light and electron microscopy. Findings from this study support the conclusion that anaplastic tumor cells arise in preexisting differentiated thyroid cancer and that associated multinucleated giant cells are formed by the fusion of carcinoma cells.

Aged↗
PubMed1987

Thromboxane A2 as an enhancing factor of coronary vasospasticity in variant angina.

To clarify the role of thromboxane A2 (TXA2) in evoking coronary spasm, we compared coronary arterial spasticity induced by ergonovine maleate (EM) with coronary sinus thromboxane B2 (TXB2: a stable catabolite of TXA2) in 34 patients with documented variant angina and 11 patients with chest pain syndrome (CPS). We also examined the effect of OKY-1581 (8 mg/kg, i.v.), a TXA2 synthetase inhibitor, on the coronary arterial spasticity of these patients. When blood samples were taken from coronary sinus just before EM test, all patients with variant angina exhibiting markedly augmented TXB2 levels (424 +/- 138 pg/ml), had positive EM test results, while CPS exhibiting lower TXB2 levels (223 +/- 38 pg/ml), had negative EM test. We found that the amounts of EM needed to induce coronary spasm were inversely correlated with TXB2 levels in coronary sinus. In 7 out of these 8 patients, OKY-1581 was found to attenuate the increased spasticity with reduction of coronary sinus TXB2 levels. In 3 patients, an EM rechallenge at symptomatically quiescent stage resulted in negative test with augmented TXB2 levels being markedly decreased. These findings indicate that increased TXA2 in circulating plasma is closely correlated with the hypersensitivity of coronary arteries to EM in patients with variant angina, suggesting a possible role of augmented TXA2 production in the enhancement of coronary vascular spasticity.

Adult↗
PubMed1986

Effect of OKY-046, a thromboxane A2 synthetase inhibitor, on arachidonate-induced platelet aggregation: possible role of "prostaglandin H2 steal" mechanism.

To clarify the mode of action of a selective thromboxane A2 (TXA2) blockade in platelet reactivity, we examined the effect of (E)-3-[4-(1-imidazolylmethyl) phenyl]-2-propenoic acid hydrochloride (OKY-046), a potent TXA2 synthetase inhibitor, on human platelet aggregation induced by arachidonic acid (1 mM) in the absence and presence of aspirin-treated aortic microsomes containing prostacyclin (PGI2) synthetase activity ex vivo. The production of TXA2 and PGI2 in platelet rich plasma was determined by the amounts of their stable catabolites, TXB2 and 6-keto-PGF1 alpha respectively, measured by radioimmunoassay. In the absence of aortic microsomes, OKY-046 (greater than 10(-5) M) produced more than 90% inhibition of TXA2 production, whereas platelet aggregation was less inhibited, about 40% inhibition over control, by OKY-046 in that concentration. In the presence of aortic microsomes, the inhibitory effect of OKY-046 on platelet aggregation was markedly augmented in a dose-dependent manner in proportion to the increment of PGI2 production, which paralleled the OKY-046-induced inhibition of TXA2. These results suggest that a selective TXA2 blockade produces effects on platelet aggregation mainly in dual fashion in the presence of PGI2 synthetase: one is due to mere inhibition of TXA2 synthetase and the other is due to the enhancement of PGI2 production probably involving "prostaglandin H2 (PGH2) steal" mechanism, in which PGH2 accumulated in platelets is partly converted to a substrate of PGI2 synthetase in aortic microsomes to produce PGI2.

Acrylates↗
PubMed1986

[Malignant paraganglioma of the peri-iliac artery].

A malignant nonfunctioning paraganglioma of the pelvic retroperitoneum (left external iliac artery) with metastases to the femoral lymph nodes was found in a 68-year-old woman at exploratory laparotomy. Light microscopy showed a typical alveolar pattern with fine vascular stroma. The tumor cells had finely granular eosinophilic cytoplasm and oval to round nuclei with pleomorphism and mitotic figures, Grimelius stain showed no argyrophilic granules, but S 100 protein was demonstrated in the cytoplasm by the PAP method of Sternberger. Formaling fixed tissues were examination by electron microscopy, and dense core granules consistent with neurosecretory granules were found in the cytoplasm of some tumor cells.

Aged↗
PubMed1985

Syntheses and differentiating action of vitamin D endoperoxides. Singlet oxygen adducts of vitamin D derivatives in human myeloid leukemia cells (HL-60).

Singlet oxygen adducts of various vitamin D derivatives, 6,19-dihydro-6,19-epidioxyvitamin D (vitamin D endoperoxides, 2 and 2'), were chemically synthesized, and their biological activity in inducing differentiation of a human myeloid leukemia cell line (HL-60 cells) was examined. The potency of the endoperoxides derived from vitamin D derivatives possessing the 1 alpha-hydroxyl group such as 1 alpha, 25-dihydroxyvitamin D3 endoperoxides (2b and 2b') was markedly (10(-2)) diminished relative to the respective parent vitamin D compounds. In contrast, 25-hydroxyvitamin D3 endoperoxides [25-(OH)D3 endoperoxides, 2a and 2a'] and their analogues fluorinated at the 24- or 26- and 27-positions were 2.5-10 times more potent than 25-hydroxyvitamin D3 (1a) in spite of the absence of the conjugated triene structure typical of vitamin D compounds. The potency of these vitamin D endoperoxides (2 and 2'), especially those lacking the 1 alpha-hydroxyl group, in inducing differentiation of HL-60 cells was not correlated with their activity in binding to the cytosol receptor for 1 alpha, 25-dihydroxyvitamin D3 (1b). The binding efficiency to the receptor was relatively lower than the differentiating activity. To examine the action of vitamin D endoperoxides, carbon analogues of 25-(OH)D3 endoperoxides, two C-6 epimers of 25-hydroxy-6,19-dihydro-6,19-ethanovitamin D3 (6 and 6'), were synthesized. The carbon analogues (6 and 6') had no potential to induce differentiation of HL-60 cells. These results suggest that vitamin D endoperoxides (2 and 2') express their biological activity probably after being converted to some other compounds.

Binding, Competitive↗
PubMed1985

A putative Ca2+-binding protein: structure of the light subunit of porcine calpain elucidated by molecular cloning and protein sequence analysis.

cDNA clones specific for the light subunit of porcine calpain I have been isolated from a porcine kidney cDNA library. The complete primary structure of the light subunit has been revealed by nucleotide sequence analysis of the cDNA clones isolated and amino acid sequence analysis of peptides isolated from the purified mature protein. We found that the light subunit contains two distinct domains. Domain I, the amino-terminal half, has two unusually long, paired polyglycyl sequences and may serve as a binding site to the heavy subunit. Domain II, the carboxyl-terminal half, is a region highly homologous to the putative Ca2+-binding domain of the heavy subunit of chicken calpain elucidated recently. This region has four potential Ca2+-binding sites, each having the "E-F hand" structure. Our results suggest that the Ca2+-mediated proteolytic activity of calpain is controlled through the cooperative and/or sequential actions of multiple Ca2+-binding sites present in both two-subunit molecules, heavy and light subunits of calpain.

Amino Acid Sequence↗
PubMed1984

Dependence of lethality induced by a direct DNA perturbation of synchronized human diploid fibroblasts on different periods of the DNA synthetic period (S phase).

The cytotoxic effect of a direct perturbation of DNA during various portions of the DNA synthetic period (S phase) of cultured human diploid fibroblasts was examined. The cells were synchronized by a period of growth in low serum with a subsequent blockage of the cells at the G1/S boundary by hydroxyurea. This method resulted in over 90% synchrony, although approximately 20% of the cells were noncycling. Synchronized cells were treated for each of four 2-hour periods during the S phase with 5-bromodeoxyuridine (0.1-10 microM), followed by irradiation with near-UV (5-10 min). The 5-bromodeoxyuridine-plus-irradiation treatment was cytotoxic, while treatment with 5-bromodeoxyuridine alone or irradiation alone was not cytotoxic. The cytotoxicity was dependent upon the periods of S phase during which treatment was administered. The highest lethality was observed for treatment in early to middle S phase, particularly in the first 2 hours of S phase, whereas scarce lethality was observed in late S phase. The extent of substitution of 5-bromodeoxyuridine for thymidine in newly synthesized DNA was similar in every period of the S phase. Furthermore, no specific period during S phase was significantly more sensitive to treatment with respect to DNA damage, as determined by an induction of unscheduled DNA synthesis. These results suggest that a certain region or regions in the DNA of human diploid fibroblasts, as designated by their specific temporal relationship in the S phase, may be more sensitive to the DNA perturbation by 5-bromodeoxyuridine treatment plus near-UV irradiation for cell survival.

Bromodeoxyuridine↗
PubMed1984

Cytotoxicity, chromosome aberrations and unscheduled DNA synthesis in cultured human diploid fibroblasts induced by sodium fluoride.

The effects of exposure of cultured human diploid fibroblasts (JHU-1 cells) to sodium fluoride have been studied with respect to cytotoxicity and induction of chromosome aberrations and unscheduled DNA synthesis (UDS) Cytotoxicity of NaF on JHU-1 cells, as determined by a decrease in colony-forming ability, linearly increased with increasing dose of NaF (50-150 micrograms/ml) or exposure time (1-24 h). Treatment of the cells with 50 micrograms/ml NaF for 24 h resulted in a lethality (approximately 70%) similar to that obtained with 100 micrograms/ml for 12 h. A linear increase in cytotoxicity was observed as a fraction of the product of NaF treatment time and dose. JHU-1 cells treated with 20-50 micrograms/ml NaF for 12 or 24 h were analyzed for chromosome aberrations. A significant increase in the frequency of chromosome aberrations at the chromatid level was observed in treated cells in a dose-dependent manner. For detection of UDS, confluent JHU-1 cells were cultured with medium containing low serum and then exposed to NaF in the presence of 10 mM hydroxyurea. Treatment with 100-400 micrograms NaF/ml for 4-24 h reproducibly elicited UDS in a dose-related fashion as determined by direct scintillation counting of [3H]thymidine incorporated into DNA during repair synthesis. These results suggest that NaF causes DNA damage in human diploid fibroblasts in culture.

Cell Survival↗