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Biomedical subjects

H Kuriki

Publications and source records attributed to H Kuriki.

17 recordsLinked to original sources
PubMed1992

A case of deletion of the short arm of chromosome 10 with severe hearing loss and brainstem dysfunction.

A male newborn infant with a deletion of the short arm of chromosome 10p 14 was described. In addition to the typical clinical features, electrophysiologic studies showed brainstem dysfunction and severe hearing loss when examined with auditory brainstem response and photopalpebral reflex. These electrophysiologic studies may be of benefit for early evaluation of brainstem functions and hearing ability of the patients of such chromosomal aberration and may also be useful predictors of psychomotor development.

Abnormalities, Multiple↗
PubMed1992

Existence of phosphoinositide-specific phospholipase C in rat liver nuclei and its change during liver regeneration.

We found phosphoinositide-specific phospholipase C (PtdIns-PLC) activity in nuclei isolated from rat liver. The enzyme hydrolyzed phosphatidylinositol, phosphatidylinositol 4-monophosphate (PIP) and phosphatidylinositol 4,5-bisphosphate in a Ca(2+)-dependent manner, and produced inositol mono-, bis-, and triphosphate, respectively. Neither phosphatidylcholine, phosphatidylethanolamine, nor phosphatidylserine was utilized as a substrate. After partial hepatectomy, the PtdIns-PLC activity in isolated nuclei increased transiently in the S phase (20-22 h post-hepatectomy), to 2.5-fold higher than in the control, when measured with PIP. This result suggests a close relationship between the nuclear PtdIns-PLC, especially its PIP-hydrolyzing activity, and cell proliferation.

Animals↗
PubMed1992

Decrease in regeneration capacity of rat liver after external biliary drainage.

In order to discover the effect of external biliary drainage on liver regeneration, we have produced a model system carrying cannula in the common bile duct of rat liver and examined the regeneration capacity of liver after partial hepatectomy under various conditions. Previously we have shown that hepatic cells proliferate by obstructive jaundice alone without partial hepatectomy [Terasaki et al; Jpn J Cancer Res 1991;82:170-175]. In the present study, we showed that DNA polymerase-alpha was induced by partial hepatectomy of rats suffering from obstructive jaundice and the induced level was similar to that of the normal regenerating liver. The level of DNA polymerase-alpha activity corresponded well to the liver regeneration capacity estimated by mitotic index. Contrary to our expectation, external biliary drainage for obstructive jaundice markedly suppressed the regeneration capacity of the remaining liver which was estimated by DNA polymerase-alpha activity, mitotic index and [3H]thymidine incorporation. The suppression may be due to the external biliary drainage itself because the liver regeneration of normal rats without jaundice was also suppressed by the biliary drainage. These results suggest that the external biliary drainage seriously suppresses the regeneration capacity of liver at least at the early stage of obstructive jaundice.

Animals↗
PubMed1992

Calcium channel blocker-like action of reserpine in smooth muscle.

The effect of reserpine on vascular and intestinal smooth muscles was examined. In these muscles, reserpine inhibited the high K(+)-induced contraction, and this inhibitory effect was antagonized by the increase in external Ca2+ concentration and also by a Ca2+ channel activator, Bay k8644. In rabbit aorta, increases in cytosolic Ca2+ level and muscle tension due to high K+ were inhibited in parallel by reserpine. These results suggest that reserpine inhibits L-type Ca2+ channels to inhibit smooth muscle contraction.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1991

Growth-associated changes in fatty acid compositions of nuclear phospholipids of liver cells.

To know the possible relationships between nuclear phospholipids and cell proliferation, we have extensively analyzed phospholipids extracted from the nuclei of rat hepatic cells at various growth states. The content of phospholipid in nuclei as well as its composition was similar among liver cells tested, i.e., the regenerating rat livers (28 h, post-hepatectomy), sham-operated or non-treated control livers, and rat ascites hepatoma, AH7974 cells. In contrast, the fatty acid compositions of phospholipids differed from each other among these cells. At the 2-position of phospholipids in the regenerating liver nuclei at 28 h after partial hepatectomy, 18:1 (oleic acid) increased transiently at the expense of 20:4 (arachidonic acid) and 22:6 (docosahexaenoic acid), compared with those in the sham-operated control nuclei. This change in fatty acid composition was commonly observed throughout all phospholipids analyzed, i.e., phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylinositol (PI) and phosphatidylserine (PS). On the other hand, the change at 1-position was rather limited: in the regenerating liver nuclei (28 h), 18:1 increased only in PC at the expense of 18:0 (stearic acid). The similar and more marked deviation at the 2-position was observed with AH7974 nuclei it contained approximately 2-times more of 18:1 in PC, PE and PI than regenerating liver nuclei (28 h), and the decreased levels of 20:4 and/or 22:6. It should be noted that there were significant differences in the fatty acid compositions of PE and PS between sham-operated and non-treated controls. So, the sham-operated rat is the appropriate control for proliferation.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Induction of DNA replication and cell growth in rat liver by obstructive jaundice.

Obstructive jaundice, produced by ligating the common bile duct, induced a transient DNA replication followed by cell proliferation in rat liver. At 48 h after the operation, DNA polymerase alpha activity started to increase and reached its maximum level (more than twice the control) at day 4. At day 7, the enzyme level had decreased to the control level. Pulse-labeling experiment using radioactive thymidine showed that the rate of DNA synthesis increased approximately 2.5-fold in the same pattern as that of DNA polymerase alpha. The mitotic index in hepatocytes also increased 10-fold at day 4 and then decreased. The proliferation of liver cells induced by obstructive jaundice mimics the regeneration of partially hepatectomized liver, although the response was slightly delayed and the proliferation was transient.

Alanine Transaminase↗
PubMed1979

Studies on antianaphylactic agents. 6. Synthesis of some metabolites of 6-ethyl-3-(1H-tetrazol-5-yl)chromone and their analogues.

The metabolites of 6-ethyl-3-(1H-tetrazol-5-yl)chromone (AA-344) (1), an orally effective antiallergic agent, and their analogues were synthesized to confirm the proposed structures and to determine their activity in the rat passive cutaneous anaphylaxis (PCA) test. A glucuronic acid metabolite (6) was assigned the structure 24b, 1-deoxy-1-[5-(6-ethylchromon-3-yl)tetrazol-1-yl]-beta-D-glucopyranuronate, by the comparison of 13C NMR, mass spectra, and TLC of isomeric compounds. In 13C NMR spectra, the shift difference of the tetrazole ring carbons between a pair of isomers was more remarkable than that of the glycosidic carbons. Therefore, the former is a useful criterion for distinguishing between such isomers. Some of the metabolities and analogues were active when administered intravenously, and two metabolites (2 and 3) were also effective upon oral administration.

Animals↗
PubMed1979

Antiallergic action of 6-ethyl-3-(1h-tetrazol-5-YL) chromone (AA-344) on immediate hypersensitivity reaction in rats.

A newly synthesized compound, 6-ethyl-3-(1H-tetrazol-5-yl)chromone (AA-344) given intravenously or orally inhibited considerably the 72-hr passive cutaneous anaphylaxis (72-hr PCA) induced by IgE in rats. The antiallergic action of AA-344 was neither due to the antihistamine or antiserotonin effect nor was it mediated via adrenergic mechanisms. The results obtained in a double sensitization with two IgE antibodies suggest that AA-344 may not impair antigen-antibody combination but probably prevents the release of chemical mediators including histamine. This assumption was supported by observation that AA-344 inhibited a reduction in the skin histamine content caused by the 72-hr PCA, without effect on the compound 48/80-induced histamine reduction. AA-344 also partially inhibited the IgGa-mediated 3-hr PCA in rats. These results indicate that the inhibitory action of AA-344 on the immediate hypersensitivity reactions is due to prevention of the release of chemical mediators from the mast cells, by acting on some process in sequential events leading to the mediator release following antigen-antibody combination.

Adrenalectomy↗
PubMed1979

Inhibitory action of 6-ethyl-3-(1H-tetrazol-5-YL)chromone (AA-344) on IgE, IgGa- or chemical agent-induced histamine release from isolated rat mast cells.

The antiallergic action of 6-ethyl-3-(1H-tetrazol-5-yl)chromone (AA-344) was studied on isolated rat peritoneal mast cells. AA-344 clearly inhibited the IgE-mediated release of histamine caused by various concentrations of antigen and the 50% inhibitory concentration was 0.1 microM. On the IgGa-mediated release of histamine, a peak inhibition of AA-344 was observed at 10 microM. The histamine release induced by chemical agents such as concanavalin A, dextran and compound 48/80 was depressed by AA-344 at the range of 0.1--1 mM. The results obtained in this study indicate that the antiallergic action of AA-344 is due to selective inhibition on the immunological release of the chemical mediator from mast cells.

Animals↗
PubMed1979

Effect of 6-ethyl-3-(1H-tetrazol-5-yl)chromone (AA-344) on the immediate and delayed hypersensitivity reactions.

Effects of 6-ethyl-3-(1H-tetrazol-5-yl)chromone (AA-344) on the experimental models of the type I-IV allergic reactions were studied in comparison with those of disodium cromoglycate (DSCG), dexamethasone and other agents. AA-344 showed inhibitory effects on the homologous passive cutaneous anaphylaxis and the passive systemic anaphylaxis in guinea pigs. However, it had only a slight or little effect on the Forssman shock in guinea pigs, the complete-dependent cytolysis of mast cells in rats, the Arthus reaction in guinea pigs and the tuberculin reaction and the contact sensitivity in mice. DSCG was less effective, using these experimental models. Dexamethasone showed a suppressive effect on the type III and IV allergic reactions. The results indicate that AA-344 selectively suppresses the type I allergic reaction.

Animals↗
PubMed1975

Studies on antianaphylactic agents. 4. Synthesis and structure-activity relationships of 3-(4-oxo-4H-1-benzopyran-3)acrylic acids, a new series of antiallergic substances, and some related compounds.

The syntheses of trans-3-(4-oxo-4H-1-benzypyran-3)acrylic acid and a number of analogs shown to be highly active in antiallergic bioassays are described. These compounds are of possible value in the treatment of asthma. The structural requirements for biological activity are discussed with reference to the type of the substituents on the chromone ring or positions of linkage of the acrylic acid on the pyrone ring.

Acrylates↗