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Biomedical subjects

H Kido

Publications and source records attributed to H Kido.

At least 217 records · Page 12Linked to original sources
PubMed1986

Diacylglycerol amplifies the induction in vivo of tyrosine aminotransferase and ornithine decarboxylase by glucocorticoid.

In adrenalectomized rats, diacylglycerol, a potent activator of protein kinase C, specifically enhanced the induction of tyrosine aminotransferase and ornithine decarboxylase by even maximally effective doses of dexamethasone phosphate, but itself had no effect on these enzyme inductions in the absence of glucocorticoid. The amplifications of enzyme induction by diacylglycerol was dose-dependent and the time courses of the amplified inductions were similar to those of the inductions by dexamethasone phosphate alone. Since diacylglycerol did not affect the induction of these enzymes by glucagon and insulin, its amplifying effect seemed to be specific for induction by glucocorticoids.

Adrenalectomy↗
PubMed1986

A chymotrypsin-type serine protease in rat basophilic leukemia cells: evidence for its immunologic identity with atypical mast cell protease.

Activity of a chymotrypsin-type serine protease was found in a subline of rat basophilic leukemia (RBL-2H3) cells. The protease was immunologically cross-reactive with anti-atypical mast cell protease immunoglobulin (Ig) G, and its activity was inhibited in a dose-dependent manner by the antibody. The apparent m.w. of the protease that reacted with the antibody was 25,000, which was identical with that of atypical mast cell protease in rat mucosal mast cells. These results show that the chymotrypsin type serine protease in RBL-2H3 cells is immunologically identical with atypical mast cell protease, which was first purified from rat small intestine. Immunohistochemical studies showed that the protease was located not only in intracytoplasmic granules but also in organelles synthesizing protein, such as cisternae of the rough endoplasmic reticulum, perinuclear spaces, and the Golgi apparatus. However, no immunoreactivity was demonstrated in rat basophils. The activity of the protease increased in the exponential phase of growth of RBL-2H3 cells in which some activity was also detected in the medium, and it decreased in the late stationary phase.

Animals↗
PubMed1986

Torsion of the gallbladder.

A 77-year-old Japanese woman with torsion of the gallbladder was surgically treated. Perhaps because of its rarity, the diagnosis is seldom made clinically, the condition generally being recognized only at laparotomy. Discussed herein are the possibility of preoperative diagnosis of this condition and the usefulness of ultrasonotomography.

Aged↗
PubMed1986

Biological functions of serine proteases in the granules of rat mast cells.

The effects of specific low- and high-molecular weight inhibitors of chymase and tryptase and F(ab')2 of antichymase on histamine release from activated mast cells were examined. The release of histamine induced by anti-rat immunoglobulin E was markedly inhibited by F(ab')2 fragments of antichymase and the low-molecular weight inhibitor of chymase chymostatin, whereas release of histamine induced by calcium ionophore A23187 was inhibited only by chymostatin. Neither the inhibitor nor the antibody affected histamine release induced by compound 48/80. These results suggest that two main chymotrypsin-type proteases are involved in process of degranulation: one is chymase, which acts at a step before calcium entry, and the other is an unidentified protease, which acts at a step after calcium entry. These results are summarized in Figure 8. After degranulation, released chymase remains associated with the cell surface while released tryptase was found in the extracellular milieu. Tryptase converted bovine prothrombin to thrombin, as shown by increase in thrombin activity with a synthetic substrate, t-butyloxy-carbonyl-Val-Pro-Arg-4-methyl-coumaryl-7-amide. The apparent Km value toward prothrombin was relatively low (2.3 microM), suggesting that tryptase contributes to blood coagulation or the process of fibrosis in tissues. The proteolytic products of IgG1 produced by chymase had chemotactic activity for neutrophil leukocytes in vitro and in vivo. These findings indicate the possible functions of these proteases after degranulation.

Animals↗
PubMed1986

A pharmacokinetic study of clomipramine in regions of the brain.

The pharmacokinetic profiles of clomipramine (CMP) and the serial changes of its concentration in specific brain regions were investigated in rats after an acute treatment with intravenous CMP (10 mg/kg). The CMP concentrations in plasma declined triexponentially and fitted a three-compartment open model. The brain to plasma concentration ratio showed a constant value, 22.2 +/- 4.9, 30 minutes after the injection. Regional brain differences in the CMP distribution and accumulation were also found. Four hours after the injections, the hippocampus was found to have the highest drug concentration, and the concentrations in this region were in the following order; thalamus, striatum, amygdala, cortex greater than pons + medulla oblongata greater than hypothalamus, bulbus olfactorius + septum, mesencephalon greater than cerebellum. Particularly, unique kinetics were observed in the cortex, amygdala and hippocampus.

Animals↗
PubMed1985

Tryptase from rat mast cells converts bovine prothrombin to thrombin.

The effect of tryptase purified from rat peritoneal mast cells on bovine prothrombin was examined. Tryptase activated prothrombin, as evidenced by the increase in thrombin activity with a synthetic substrate, t-butyloxy-carbonyl-Val-Pro-Arg-4-methylcoumaryl-7-amide. The apparent Km value toward bovine prothrombin and the kcat value were 2.3 microM and 46.3 s-1, respectively. Studies on the time course of prothrombin activation by tryptase and by activated factor X (Xa), and analysis of the activation products on sodium dodecyl sulfate gel electrophoresis showed that the process of activation of prothrombin by tryptase was similar to that by Xa except that an intermediate of 67,000 daltons was formed.

Alpha-Globulins↗
PubMed1985

Inhibition of chymase activity by phosphoglycerides.

The activity of chymase was markedly inhibited by phosphoglycerides such as phosphatidic acid, phosphatidylserine, and phosphatidylinositol, but was not affected by acylglycerides, phosphoglyceroserine, serine, inositol, or glycerol. These results suggest that both the nonpolar hydrophobic hydrocarbon tails and the polar hydrophilic head are essential for the inhibitory effects of phosphoglycerides. Binding of a primary amine to an anionic polar head of phosphatidic acid, such as in phosphatidylserine and phosphatidylethanolamine, slightly decreased the inhibitory effect of phosphatidic acid and, conversely, binding of a strong cation to the head, such as in phosphatidylcholine, resulted in its activation of chymase. Phosphatidic acid containing an unsaturated fatty acid, such as dioleoyl phosphatidic acid, caused the same extent of inhibition as natural phosphatidic acid from bovine brain, but was 20 times more inhibitory than phosphatidic acid containing a saturated fatty acid, such as distearoyl phosphatidic acid. The inhibition by phosphatidylserine was noncompetitive and pseudoirreversible, and the Ki value was 0.54 microM. The inhibition of chymase by phosphatidylserine was pH dependent, being strong at pH 8.5 to 9.5 but weak below pH 7.5. Phosphatidylserine specifically inhibited chymase and elastase; it did not inhibit the other chymotrypsin-type serine endopeptidases tested, trypsin, papain, collagenase, carboxypeptidase A, or cathepsin D.

Animals↗
PubMed1985

Chymotrypsin- and trypsin-type serine proteases in rat mast cells: properties and functions.

Two of the major enzymes present in and released from rat mast cells are chymotrypsin-type serine protease (chymase) and trypsin-type serine protease (tryptase), and these have been postulated to be important in the inflammatory reactions. There have been no clear data regarding the trypsin-type protease in rat mast cells. Tryptase was recently purified from rat peritoneal mast cells with an associated protein (trypstatin) that inhibited the protease activity above pH 7.5. Chymase was also purified from rat peritoneal cells by employing a one-step method involving hydrophobic chromatography on octyl-Sepharose 4B or arginine-Sepharose 4B. The properties of chymase and tryptase were described in relation to substrate specificity and their relative sensitivity to inhibitors. It was found that proteolytic activities of these enzymes were modulated by naturally occurring substances, such as phosphoglycerides, long-chain fatty acids, and trypstatin. There is as yet little evidence for the physiological roles of these enzymes in the inflammatory reaction. It has been found that the specific, low-molecular-weight inhibitor of chymase, chymostatin, and that of tryptase, leupeptin, inhibit histamine release induced by addition of anti-rat IgE to mast cells. However, the inhibitors with molecular weights of more than 6000 were found to have no effect in this process. The data suggest that chymase and tryptase in mast cell granules play a crucial or significant role in the process of degranulation.

Animals↗
PubMed1985

Antibody and inhibitor of chymase inhibit histamine release in immunoglobulin E-activated mast cells.

The low-molecular-weight inhibitor of chymase, chymostatin, and F(ab')2 fragments of anti-chymase markedly inhibited histamine release induced by anti-rat immunoglobulin E (IgE) but not that induced by compound 48/80. Inhibitors with molecular weights of more than 6,000, such as alpha 1-antichymotrypsin and aprotinin, and non-immunized F(ab')2 had no effect on histamine release. These results suggest that chymase in mast cell granules plays an essential role in the process of IgE-mediated degranulation. After degranulation, released chymase was associated with the cell surface while released tryptase was present in the extracellular milieu as a complex with a protein associated with tryptase (trypstatin).

Animals↗
PubMed1984

Inhibition of chymase activity by long chain fatty acids.

The activity of chymase was markedly inhibited by fatty acids with carbon chain lengths of 14-22 at doses greater than 0.02 microM, irrespective of the number of double bonds. Cis acids with a carbon chain length of 18, such as stearic acid, oleic acid, linoleic acid, and linolenic acid were potent inhibitors, whereas the trans isomer of oleic acid, elaidic acid, showed less inhibitory activity. The extent of inhibition by oleyl alcohol was almost the same as that by oleic acid, suggesting that the acid moiety itself was not necessary for the inhibition; but a fatty acid with a terminal functional amide, oleamide, showed little inhibitory activity. The inhibition was noncompetitive and was reversible, and the Ki value of oleic acid was 2.7 microM. Stearic acid and oleic acid inhibited all chymotrypsin-type serine endopeptidases tested. The ID50 values of these fatty acids for atypical mast cell protease were higher than those for the other chymotrypsin-type serine endopeptidases tested. Other proteases, such as papain, trypsin, collagenase, and carboxypeptidase A, except cathespin D, were not affected by stearic or oleic acid.

Animals↗
PubMed1984

A simple method for purification of chymase from rat tongue and rat peritoneal cells.

Chymase was purified from rat tongue and rat peritoneal cells by a simple new method involving hydrophobic chromatography on octyl-Sepharose 4B and hydroxylapatite column chromatography. This procedure can be completed in 1 or 2 days and the recovery is 45-60% from rat tongue and 32-47% from rat peritoneal cells. The specific activity of the purified enzyme is higher than that of crystallized enzyme previously reported (Y. Sanada, N. Yasogawa, and N. Katunuma (1978) Biochem. Biophys. Res. Commun. 82, 108-113). This procedure should be particularly useful for purifying chymase on a large scale from tissues in which it is present in relatively low concentrations.

Animals↗