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Biomedical subjects

H Ohta

Publications and source records attributed to H Ohta.

At least 811 records · Page 45Linked to original sources
PubMed1981

Characterization of brush borders purified in iso-osmotic medium and microvillar membranes subfractionated from mouse small intestine.

Brush borders free of nuclei were isolated by repeated homogenization and centrifugation in iso-osmotic medium. They showed typical morphology under electron microscopy. The mean recovery and enrichment of alkaline phosphatase activity in the brush-border fraction were 50% and 17.5-fold respectively. gamma-Glutamyl transpeptidase showed a close parallelism with alkaline phosphatase and sucrase in subcellular distribution. Microvillar membranes were purified from isolated brush borders; they showed a further enrichment for alkaline phosphatase and were composed of homogeneous vesicles. Both brush-border and microvillar-membrane preparations were analysed for contamination by basolateral and endoplasmic-reticular membranes. Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis of the microvillar-membrane preparation in six different systems revealed approx. 40 components in the mol.wt. range 15 000-232 000. They were grouped into seven major classes on the basis of molecular weight and electrophoretic patterns.

Animals↗
PubMed1981

Heat-stable alkaline phosphatase in uterine cancer, with special reference to its histochemical heat-stability and the L-phenylalanine inhibition test.

We report a histochemical study of alkaline phosphatase (ALP) in normal cells of the female reproductive system, in pre-cancerous and cancerous lesions of the uterine cervix and in endometrial cancer to ascertain the incidence of ALP and its isoenzyme type. For this purpose, serial sections were subjected to heat stability and L-phenylalanine (LP) inhibition tests. The Regan-like isoenzyme, a heat-stable and LP-sensitive ALP, which has been thought to derive only from cancer or the placenta, was found in uterine cervical reserve cells and endometrial luminal surface lining cells. In contrast, ALP activity in endometrial glandular cells was found to be heat and LP sensitive. Of 183 cases of cervical neoplasia, 60 (33%) manifested non-specific ALP activity. One dysplasia and two invasive cancer cases manifested the Regan-like isoenzyme. The other 36 classifiable lesions had small-intestine ALP-like activity (marked heat and LP sensitivity) or a liver ALP-like isoenzyme (marked heat and slight LP sensitivity). Of 42 cases of endometrial cancer, all cases manifested non-specific ALP activity. Seven endometrial cancers exhibited the Regan-like isoenzyme. The other 19 cases manifested either small intestine or liver ALP-like isoenzyme. Our findings indicate that in the course of uterine carinogenesis, the ALP isoenzyme of reserve cell and endometrial glandular cells undergo a change and that enzyme deviation occurs.

Alkaline Phosphatase↗
PubMed1981

Inhibition of the mutagenicity of cooked-beef basic fraction by its acidic fraction.

By using the Salmonella/microsome system, it was found that the activity of mutagens present in the basic fraction of cooked-ground-beef was completely suppressed by addition of the acidic fraction obtained from the cooked-beef. The suppression was ascribable to the presence of oleic acid in the acidic fraction. This finding indicates that no, or diminished, mutagenicity would be found in materials containing fat.

Animals↗
PubMed1981

Endoplasmic reticulum membrane isolated from small-intestinal epithelial cells: enzyme and protein components.

Endoplasmic reticulum membrane-rich fraction was obtained by subfractionation of the light microsomes from mouse jejunal mucosal epithelial cells. It was marked by high glucose-6-phosphatase, NADPH-cytochrome c reductase, and NADH-cytochrome c reductase activities and low Na+,K+-ATPase activity. The enrichment of Na+,K+-ATPase was 180-fold higher in the basolateral membranes than in the endoplasmic reticulum membrane-rich fraction relative to glucose-6-phosphatase. The protein peak that was phosphorylated in a Na-dependent manner was prominent in the basolateral membranes while it was a minor peak in the endoplasmic reticulum membrane-rich fraction. Under the electron microscope the fraction was seen to be composed of homogeneous small vesicles with thin smooth membranes.

Animals↗
PubMed1981

Pulsatile venous flow in extracorporeal circulation.

Effects of pulsatile venous flow upon the microcirculation were investigated in conditions with different venous pressures by using regional perfusion in dog's hind legs. In animals with venous pressure of -18 cmH2O (Collapsed stage), venous pulsation brought about a significant increase in mean oxygen consumption ratio and suppressed a rise of mean resistance ratio significantly. In animals with venous pressure of +2 cmH2O (normal venous pressure stage), the venous pulsation was effective in a rise of mean oxygen consumption ratio but was not effective in suppression of mean resistance ratio. In animals with venous pressure of +10 cmH2O (congestive stage), no effect of venous pulsation was recognized. We suppose that the intermittent elevation of venous pressure by venous pulsation is effective for opening some capillaries in animals with venous pressure below +2 cmH2O.

Animals↗
PubMed1981

Suppression of delayed hypersensitivity by measles virus infection in guinea pigs.

A guinea pig model of mild measles virus infection was established by the intranasal inoculation with Toyoshima strain. The infection was confirmed by the development of both humoral and cell-mediated immunities to measles virus as well as by the demonstration of transient virus growth in the lymphoid tissues. The virus infection caused a transient suppression of delayed hypersensitivity to purified protein derivative (PPD) at both the induction and expression phases, whereas Jones-Mote-type hypersensitivity to ovalbumin developed in a normal fashion. In the virus-infected animals, the suppressed response to the skin reacting factor was observed as well, however in vitro responsiveness of lymphocytes to PPD was not suppressed. On the other hand, transient enhancement of skin reactivity to phytohemagglutinin by virus infection was noticed. These results may indicate subtle alterations of immune functions in guinea pigs during measles virus infection.

Animals↗
PubMed1981

[Behavioral and electroencephalographic effects of alprazolam and its metabolites (author's transl)].

The behavioral and electroencephalographic effects of alprazolam and its metabolites were investigated in mice, rats and rabbits, and compared with the data on diazepam, lorazepam and nitrazepam. Locomotor activity of mice in an open-field situation was increased with smaller doses of alprazolam and nitrazepam but not with diazepam and lorazepam. Alprazolam increased the hyperactivity induced by methamphetamine in mice. The anticonflict effects of alprazolam in rats were more potent than those of diazepam and lorazepam. In suppressing hyperemotionality and muricide of olfactory bulbectomized rats, alprazolam was more potent than diazepam and fairly equal to that of lorazepam. Muricide of raphe-lesioned rats was markedly inhibited by alprazolam. Mescaline-induced head-twitches in mice were more markedly increased with alprazolam than with nitrazepam and diazepam. Alprazolam, diazepam and lorazepam prevented both maximal electroshock and pentetrazol convulsions in mice. Alprazolam was more potent than diazepam and lorazepam in potentiating thiopental, ether and ethanol anesthesia in mice. In the impaired rotarod performance, alprazolam was more potent than diazepam and lorazepam in mice, but was much less potent than diazepam and lorazepam in mice, but was much less potent than lorazepam in rats. In conscious rabbits with chronically implanted electrodes, alprazolam induced a drowsy EEG pattern and depressed the EEG arousal response not only to auditory stimulation but also to mesencephalic reticular stimulation. The EEG effect of alprazolam was approx. twice that of diazepam. The pharmacological activity of alpha-hydroxyalprazolam was approx. one third that of alprazolam. However, 5-chloro-2-(3-hydromethyl-5-methyl-4H-1, 2,4-triazolo-4-yl) benzophenone showed no pharmacological activity. These results indicate that alprazolam possesses pharmacologic properties characteristic to benzodiazepines and that the activity is more potent than diazepam. In addition, alprazolam seems to have a specific effect on the central serotonergic mechanisms.

Aggression↗