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M Ota

Publications and source records attributed to M Ota.

At least 415 records · Page 23Linked to original sources
PubMed1976

[Prostaglandins].

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Endometrium↗
PubMed1975

Lowering effect of carbon tetrachloride on microsomal cytochrome P-450 of rat liver.

The lowering effect of carbon tetrachloride (CCl4) on the amount of hepatic microsomal cytochrome P-450 of male rats was studied in vitro. It was found that CCl4 added directly into the media containing microsomal supensions decreased the amount of cytochrome P-450 detectable by difference spectra at zero time of incubation. The incubation of the media with CCl4 at 37 degrees in an open system or in a closed system did not decrease the content of cytochrome P-450. As cytochrome P-420 was not detected in the addition of CCl4 lower than 10 mul, it was postulated that the decrease in the content of cytochrome P-450 was not due to its conversion to cytochrome P-420. The activity of NADPH-cytochrome c reductase was not affected by CCl4. The results indicate that the decrease of the amount of detectable cytochrome P-450 by CCl4 is due to the destruction of cytochrome P-450 and the binding of cytochrome P-450 with CCl4in a lower concentration of CCl4 and in addition it is due to the conversion of cytochrome P-420 from cytochrome P-450 in a higher concentration of CCl4.

Animals↗
PubMed1975

Purification and characterization of lipoprotein lipase from pig myocardium.

1. Lipoprotein lipase was purified from pig myocardium by a two-step purification procedure involving (a) the formation of an enzyme-substrate complex and (b) affinity chromatography on Sepharose which contained covalently linked heparin. The purified enzyme gave in sodium dodecyl sulphate-polyacrylamide-gel electrophoresis one main band with an apparent molecular weight of 73 000. The enzyme, which was purified 70 000-fold, had a specific activity of 860 mumol of unesterified fatty acid liberated/h per mg of protein. 2. The purified enzyme hydrolysed [14C]triolein emulsions in the absence of added cofactors but its activity was increased fivefold by adding normal human serum. Of the low-density lipoprotein apoproteins only apolipoprotein CII could be substituted for serum in activating the enzyme. This lipase had maximum activity at 0.05-0.15 M-NaCl. Heparin increased the activity of the purified enzyme twofold at low concentrations, but high concentrations inhibited. The triglyceride lipase of pig myocardium thus resembles lipoprotein lipase purified from adipose tissue and from plasma, but is clearly different from pig hepatic triglyceride lipase.

Animals↗
PubMed1975

Interferon production in mice by the capsular polysaccharide of Klebsiella pneumoniae.

The capsular polysaccharide of Klebsiella pneumoniae (CPS-K) type 1, Kasuya strain, induces interferon production in the blood of mice when injected intravenously. CPS-K resembles bacterial endotoxin (lipopolysaccharide) in the time pattern of interferon production, with peak levels 2h after injection. CPS-K on a weight basis exhibits a more potent interferon-inducing effect than lipopolysaccharide. The active substance responsible for the interferon-inducing activity of CPS-K is the neutral CPS-K antigen which is antigenically distinct from the O antigen and from acidic CPS-K (the type-specific capsular antigen). Neutral CPS-K from the Kasuya strain has been already found to exhibit a strong adjuvant effect on antibody responses to various antigens in mice. Preparations of neutral CPS-K from other strains of K. pneumoniae, of which adjuvant action is only very weak, exhibit interferon-inducing activity similar to the preparation from the Kasuya strain. Heterologous and homologous tolerance to re-induction of interferon is produced by a prior injection (one each) of LPS, neutral CPS-K, and acidic CPS-K. No simple correlation exists between the inducing and tolerogenic capabilities of these substances.

Animals↗
PubMed1975

Inhibition of ovulation induced with PMS and HCG by a melatonin-free extract of bovine pineal powder.

Using borate buffer a substance that suppresses the ovulation induced with PMS and HCG in immature mice was obtained from acetone-defatted bovine pineal powder by an extraction method similar to that used for an extraction of a gonadotropin-inhibiting substance in urine. This gonadotropin inhibitor in the pineal powder differs from melatonin or arginine vasotocin and seems to be different from the water soluble antigonadotropic substance which has been isolated from the bovine and ovine pineal. Partial purification of the gonadotropin inhibitor was accomplished by a Sephadex G-100 column.

Animals↗
PubMed1975

Glucose tolerance, serum insulin and lipid abnormalities in patients with coronary heart disease.

Blood glucose, free fatty acid and insulin responses to oral glucose and the fasting serum lipids were measured in 3 groups: 32 non-obese (mean age: 47.5 years) and 9 obese (mean age: 84.5 years), male patients with coronary heart disease and 12 non-obese male controls (mean age: 46.5 years). The oral glucose tolerance tests were repeated after 3 years in 16 of the non-obese patients with coronary heart disease. The results were as follows: 1) Glucose tolerance was impaired in 19 of 32 non-obese patients (59.4%). There was a significant correlation between impaired glucose tolerance and hyperlipidemia (hypercholesterolemia and/or hypertriglyceridemia). 2) In obese patients FFA levels at 30, 60, and 120 min after oral glucose administration were significantly elevated and FFA decrease was delayed with a drop to minimum levels at 180 min. 3) The insulin response after oral glucose administration in the group of non-obese patients with normal glucose tolerance was similar to that of non-obese controls. In the group of non-obese patients with impaired glucose tolerance, serum insulin levels went up to normal levels, but the peak was delayed. The serum insulin levels in obese patients were significantly higher than those of controls of 0, 60, 120, and 180 min. After 3 years the change in insulin response to oral glucose was not related to anginal symptoms or ECG findings, but was related to body weight change in patients with minor changes in glucose tolerance. 4) The metabolic pattern in the non-obese group with impaired glucose tolerance resembled that of "mild diabetes" in delayed response of insulin and FFA, and mild hyperlipidemia. These findings suggest that obesity may contribute to hyperinsulinemia in patients with coronary heart disease and that impaired glucose tolerance observed in patients with coronary heart disease is in part due to "latent diabetes".

Adult↗
PubMed1975

[Study on the age-hardenable silver alloy (3 rd report). III. On the ageing process of dental Ag-Pd-Cu-Au alloy (author's transl)].

The precipitation hardening process of a dental silver base alloy, Ag-28 Pd-10 Cu-12 wt % Au, was studied by means of X-ray diffraction, hardness measurement and metallographic observations. After solution treatment at 900 degrees C for 30 min, specimens were subjected to anisothermal annealing at the rate of 1 degrees C/min. PdCu ordered phase and alpha2 solid solution (Ag rich phase) precipitated hetelogeneously at the grain boundaries and then grew up into each grain. Drastic increase in hardness was recognized with the spread of nodular region. Electron microscopic observation of these precipitates showed very fine lamellar structure. It is concluded that the age hardening of this alloy could be attributed to this grain boundary precipitation and the softening at the overaged stage to the second grain boundary reaction which produced very coarse lamellar structure.

Copper↗
PubMed1975

An alpha adrenergic mechanism in the ascending reticular activating system.

The effect of electrical stimulation of the mesencephalic reticular formation (MRF) on the pyramidal tract (PT) response to cortical stimulation in adult rats was examined with and without alpha adrenergic blocking agents and other chemicals, applied intravenously, intraperitoneally or topically to the exposed cerebral cortex. 1. By MRF stimulation, the initial component of the PT response (D wave) was not significantly altered but the later component (I waves) was initially facilitated and subsequently inhibited. 2. Intravenously applied alpha adrenergic blocking agents, phentolamine and phenoxybenzamine consistently blocked reticulo-cortical inhibition. The reticulo-cortical facilitation was significantly reduced by phentolamine but the effect of phenoxybenazmine was not consistent on this mechanism. Neither the PT response nor the effect of MRF stimulation on it was affected by propranolol or atropine. 3. Phentolamine or phenoxybenazmine, topically applied to the cortical surface, blocked the reticulo-cortical inhibition but did not alter the reticulo-cortical facilitation. 4. A monoamine oxidase inhibitor, iproniazid (i.p.), significantly potentiated the reticulo-cortical inhibition but the effect on the reticulocortical facilitation was not statistically significant. 5. These results suggest that the reticular inhibitory effect on the motor cortical activity is mediated through an alpha adrenergic mechanism and the receptor site is distributed in the cerebral cortex.

Administration, Topical↗