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Biomedical subjects

M Yamaguchi

Publications and source records attributed to M Yamaguchi.

At least 1,585 records · Page 88Linked to original sources
PubMed1985

[Histochemical diagnosis of Hirschsprung's disease and 2 point rectal mucosal biopsies for selection of surgical treatment].

In order to establish the diagnostic criteria of Hirschsprung's disease by Ach. E. staining of rectal mucosal biopsy, we analysed the specimen obtained from 110 infants with abdominal distension and constipation. We found the pattern of nerve fiber proliferation was not uniform even in patients with Hirschsprung's disease. The pattern was classified into 4 types. I. total layer type (Typical type), II. lamina propria mucosal type, III. lamina submucosal type, and IV. lamina propria mucosal and lamina submucosal type. In case of types II, III, IV which do not show a typical finding, detection of Meissner's ganglion cells is the most important factor for the diagnosis of Hirschsprung's disease. Since we confirmed that the Meissner's ganglion cells were always present at the level of just above to the dentate line of the rectum in the specimen of normal controls, we concluded that 5mm oral to the dentate line was the most appropriate position of the rectal mucosal biopsy for the diagnosis of Hirschsprung's disease including patients with ultrashort segment aganglionosis. Two points rectal mucosal biopsies, namely, the biopsies from the site of 5mm and 5 cm oral to the dentate line, was useful for selection of surgical treatment in patients with short segment aganglionosis.

Acetylcholinesterase↗
PubMed1984

Protonation of the sarcoplasmic reticulum Ca-ATPase during ATP hydrolysis.

pH changes of the reaction medium (pH 6.35) following addition of MgATP were determined at 4 degrees C with sarcoplasmic reticulum vesicles in the presence of 0.1 mM CaCl2 and 5 mM MgCl2. With intact vesicles, a pronounced acidification following a slight alkalinization was induced by MgATP, indicating H+ ejection from vesicles. This agrees with previous observations by several investigators that suggested H+ counter-transport coupled to Ca2+ uptake. When vesicles were made leaky, a markedly enhanced alkalinization occurred after addition of MgATP, and then the pH returned to the level before the MgATP addition. The decay of this alkalinization coincided with the disappearance of phosphoenzyme (EP) which was formed from MgATP and the Ca-ATPase of sarcoplasmic reticulum. The CaCl2 concentration dependence of the alkalinization agreed well with that of EP formation. Furthermore, the alkalinization was prevented by modification of a specific SH group of the enzyme essential for EP decomposition. These findings give evidence that the alkalinization with leaky vesicles represents protonation of the enzyme during ATP hydrolysis. The enhanced alkalinization with leaky vesicles suggests protonation occurring inside vesicles. When CaATP in place of MgATP was added in the absence of MgCl2, neither the H+ ejection from intact vesicles nor the enhanced alkalinization with leaky vesicles occurred. Under these conditions, CaATP did not efficiently support active Ca2+ uptake. These results are compatible with the view that the observed protonation could represent an initial event occurring inside vesicles in the H+ countertransport coupled to Ca2+ uptake.

Adenosine Triphosphate↗
PubMed1984

Modulation of the actin-activated adenosinetriphosphatase activity of myosin by tropomyosin from vascular and gizzard smooth muscles.

Tropomyosins from bovine aorta and pulmonary artery exhibit identical electrophoretic patterns in sodium dodecyl sulfate but differ from tropomyosins of either chicken gizzard or rabbit skeletal muscle. Each of the four tropomyosins binds readily to skeletal muscle F-actin as indicated by their sedimentation with actin and by their ability to maximally stimulate or inhibit actin-activated ATPase activity at a molar ratio of one tropomyosin per seven actin monomers. Smooth and skeletal muscle tropomyosins differ in their effects on activity of skeletal myosin or heavy meromyosin (HMM); the former can enhance activity under conditions in which the latter inhibits. Gizzard and arterial tropomyosins are usually equally effective in stimulating ATPase activity of skeletal acto-HMM, but at high concentrations of Mg2+ gizzard tropomyosin is more effective, a result that cannot be attributed to differences in the binding of the two tropomyosins to F-actin. The effects of tropomyosin also depend on the type of myosin; tropomyosin enhances activity of gizzard myosin under conditions in which it inhibits that of skeletal myosin. Increasing the pH or the Mg2+ concentration can reverse the effect of tropomyosin on actin-stimulated ATPase activity of skeletal HMM from activation to inhibition, but this reversal is not found with gizzard myosin. Activity in the absence of tropomyosin is independent of pH, and the loss of activation with increasing pH is not accompanied by loss of binding of tropomyosin to actin.

Actins↗
PubMed1984

Determination of bestatin in serum by high-performance liquid chromatography with fluorescence detection.

A simple method for the determination of bestatin and its major metabolite in man, p-hydroxybestatin, in human serum was investigated; the method employs high-performance liquid chromatography with fluorescence detection. Bestatin and p-hydroxybestatin are oxidized to phenylacetaldehyde and p-hydroxyphenylacetaldehyde, respectively, with periodate, which are then converted into fluorescent compounds with 4,5-dimethoxy-1,2-diaminobenzene. The compounds are separated by reversed-phase chromatography on LiChrosorb RP-18. The detection limits of bestatin and p-hydroxybestatin are 0.2 and 0.4 microgram/ml serum, respectively. This method permits the precise determination of bestatin in serum (20 microliter) from patients administered bestatin. p-Hydroxybestatin in serum can not be measured by this method because of its low concentration (less than the detection limit).

Chromatography, High Pressure Liquid↗
PubMed1984

Distribution and characterization of the TRH receptors in the CNS of ataxic mutant mouse.

The distribution of TRH receptors in the membrane fraction of the CNS in ataxic mutant mice (C3Hf/Nem-rol and C57BL/6j-tg) was studied. TRH binding sites in cerebellum and frontal lobe of the ataxic form and the non-ataxic heterozygotes of Rolling Mouse Nagoya were decreased in comparison with the controls, whereas those in the spinal cord of Rolling Mouse Nagoya and cerebellum of Tottering Mouse were increased in the ataxic mice over the controls. Kinetic studies were performed on cerebrum and cerebellum of the different ataxic mutant mice. Such species differences in the distribution of the TRH receptors have to be considered in the action of TRH in individual ataxia cases.

Animals↗
PubMed1984

Distribution and characterization of the GABA receptors in the CNS of ataxic mutant mouse.

In an attempt to elucidate molecular pathogenesis of ataxia without cytological abberations in the cerebellum, Rolling Mouse Nagoya (C3Hf/Nem-rol) was used to study distribution of GABA receptors in membrane fractions. Among muscimol binding sites of various regions in the ataxic CNS, those in pons and medulla were significantly decreased (P less than 0.001) compared with control and non-ataxic heterozygote CNS, followed by cerebellum at a lower degree of significance (P less than 0.01). The kinetic studies demonstrated that dissociation constants of high- and low-affinity binding sites of muscimol of each control and those of ataxic mutant mouse were similar, i.e., KH = 41 nM and KL = 1.1 microM, respectively. GAD in the various regions was assayed, and it showed higher activity in the thalamus and hypothalamus, and lower activity in the cerebellum, of the ataxic mutant mouse as compared to that of the control mouse.

Animals↗
PubMed1984

Distribution and characterization of the glutamate receptors in the CNS of ataxic mutant mouse.

In a search for neurochemical involvement in cerebellar ataxia, Rolling Mouse Nagoya (C3Hf/Nem-rol), which shows only hypoplasia of the cerebellum but no pathological configuration of the cerebellar structure, was used to study glutamate receptors in the CNS. Kainic acid binding sites were significantly decreased in the thalamus, hypothalamus, pons, and cerebellum, and in the frontal cortex of both the ataxic mutant mouse and the non-ataxic heterozygote. Only spinal cord and midbrain of the ataxic mutant mouse showed decreased distribution of kainate binding sites in the membrane fraction. Among enzymes responsible for supplying glutamate to the receptor, GDH showed higher activity in the spinal cord of the ataxic mutant mouse.

Animals↗
PubMed1984

6-Keto prostaglandin F1 alpha, thromboxane B2 and 13,14-dihydro-15-keto prostaglandin F levels in maternal and fetal plasma.

In order to investigate the physiological roles of prostaglandins during pregnancy, delivery and the postpartum period, the plasma concentration of 6-keto prostaglandin F1 alpha (6-keto PGF1 alpha), a stable metabolite of prostacyclin, thromboxane B2 (TXB2), a stable metabolite of thromboxane A2, and 13,14-dihydro-15-keto prostaglandin F(PGFM) were measured by specific radioimmunoassay. In addition, at delivery, plasma 6-keto PGF1 alpha and PGFM concentration were measured in maternal, umbilical arterial and venous plasma. 6-Keto PGF1 alpha, TXB2 and PGFM levels did not change during pregnancy. 6-Keto PGF1 alpha level at delivery was somewhat higher than during pregnancy but not significantly so. PGFM level was significantly higher than during pregnancy. Umbilical arterial 6-keto PGF1 alpha concentration was significantly higher than umbilical venous or maternal plasma at delivery. Umbilical venous 6-keto PGF1 alpha level was somewhat higher than that of maternal plasma but the increase was not significant. There was no significant difference between umbilical arterial and venous concentrations of PGFM, but maternal PGFM level was significantly higher than that of fetal plasma. In the postpartum period, PGFM and TXB2 concentrations were significantly higher than before delivery. However 6-keto PGF1 alpha level in the postpartum period did not significantly differ from before delivery. The results of this study may indicate high prostacyclin production by the fetus and that PGF and TXA2 concentration change in the postpartum period.

6-Ketoprostaglandin F1 alpha↗
PubMed1984

Configurational changes in rat liver nuclear chromatin caused by azo dyes.

The effects of azo dyes on the chromatin configuration of isolated rat-liver nuclei were examined by electron microscopy for elucidation of the mechanism of dye-stimulated in vitro RNA synthesis. Sunset Yellow FCF had no effect on the incorporation of [3H]UTP into RNA but amaranth and Ponceau 3R stimulated incorporation approximately two- and 3.5-fold, respectively. Sunset Yellow FCF did not produce any major alteration in liver nuclei. Isolated liver nuclei treated with amaranth or Ponceau 3R showed dissociation of heterochromatin and the nucleoli lost their fine-granular structure acquiring a coarse-granular configuration. The dense structure of heterochromatin in liver nuclei treated with Ponceau 3R was completely dissociated and appeared as a lace-like configuration. These results suggest that both Ponceau 3R and amaranth stimulate in vitro RNA synthesis by causing the dissociation of heterochromatin in isolated rat-liver nuclei.

Amaranth Dye↗
PubMed1984

Decrease in insulin secretion related to hypocalcemia induced by a high dose of zinc in rats.

A single oral administration of zinc (Zn), sufficient to induce hypocalcemia, caused a decrease in glucose tolerance in fasted rats. This decrease resulted from reduction of insulin secretion. The restoration of Zn-induced hypocalcemia completely prevented the decrease in glucose tolerance and insulin secretion. These results suggest that the effect of Zn administration on insulin secretion in rats is a consequence of hypocalcemia.

Administration, Oral↗
PubMed1984

Calcitonin increases alanine aminotransferase activity related to calcium in the hepatic mitochondria of rats.

The effect of calcitonin (CT) on alanine aminotransferase activity and calcium content in the hepatic mitochondria of intact rats was investigated. A single subcutaneous administration of CT (synthetic [Asu1,7] eel calcitonin; 80 MRC mU/100 g body weight) produced a significant increase in alanine aminotransferase activity and a corresponding elevation of calcium content. Those increases were also observed with the lowest dose of CT (20 MRC mU/100 g). The mitochondrial calcium depletion by 10 mM EGTA treatment produced a remarkable reduction in alanine aminotransferase activity increased by CT, although EGTA treatment did not alter basal enzyme activity. Addition of calcium ion (1-10(3) microM) into the EGTA-treated mitochondria, however, produced a significant increase in alanine aminotransferase activity. The enzyme activity increased by CT was not inhibited by the presence of calmodulin inhibitor, W-7 (1-10(3) microM). These results suggest that the mitochondrial calcium increased by CT administration directly activates alanine aminotransferase in the hepatic mitochondria of rats.

Alanine Transaminase↗