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Biomedical subjects

H Murakami

Publications and source records attributed to H Murakami.

At least 721 records · Page 40Linked to original sources
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

Acetylcholine release elicited by electrical stimulation and its sites of action in smooth muscle of Mytilus.

The effects of strychnine (ST), BTM-1042, hexamethonium (Hexa), tetraethylammonium (TEA), atropine (AT), benactyzine ( Bena ) and dithiothreitol (DTT) on phasic contraction in response to electrical pulses in Mytilus smooth muscle ( ABRM ) have been examined. ST (10(-7) to 5 X 10(-5) M), BTM-1042 (10(-5) to 10(-3) M), Hexa (10(-5) to 10(-3) M) and TEA (10(-5) to 10(-3) M) dose-dependently depressed the contraction. AT (10(-5) to 10(-3) M) had a little influence on the depression of the contraction, while Bena (5 X 10(-6) to 5 X 10(-4) M) dose-dependently depressed the contraction. DTT (10(-4) to 3 X 10(-3) M) depressed the contraction. These findings suggest that the mechanism of acetylcholine-release from excitatory nerve endings is partly similar to its release in the mammalian smooth muscle, and that the cholinergic receptors in ABRM are more like nicotinic receptors than muscarinic ones.

Acetylcholine↗
PubMed1984

Characterization of complementary DNA clones coding for two forms of 3-methylcholanthrene-inducible rat liver cytochrome P-450.

Double-stranded DNA complementary to the partially purified mRNA prepared from 3-methylcholanthrene (MC)-treated rat liver was constructed and cloned in Escherichia coli. Twenty clones were verified to carry a complementary DNA (cDNA) insert coding for MC-inducible cytochrome P-450 by positive hybridization translation assay and immunochemical assay with anti-cytochrome P-450 antibody. The identified cDNA clones were divided into at least two groups on the basis of comparison of restriction maps of the cDNA inserts. A clone pAU157 whose cDNA insert was approximately 2.7 kb in length contained nearly full-length mRNA information for cytochrome P-450MC or P-450c, which is the major form of MC-inducible cytochrome P-450. Other cDNA clones pTZ286-pTZ330 contained the 1.2 kb sequence complementary to cytochrome P-450d mRNA. RNA blot analysis revealed that pAU157 and pTZ286-pTZ330 cDNA clones were derived from 22S and 18S mRNAs, respectively, both of which were induced in rat liver by MC treatment. Sequence analysis revealed that there were closely homologous sequence regions in pAU157 and pTZ286-pTZ330 cDNA inserts and most of the homologous sequences were localized in two limited coding regions of the two cytochrome P-450 species. pAU157 encoded the total amino acid sequence of cytochrome P-450MC or P-450c and pTZ286-pTZ330 coded for the C-terminal 368 amino acid residues of cytochrome P-450d. Two highly homologous regions were found in the amino acid sequences of these cytochrome P-450 species.

Amino Acid Sequence↗
PubMed1984

Effect of phorbol esters on the release of growth hormone and prolactin from rat pituitary cells cultured in monolayer.

The effect of phorbol diester tumour promoters on the release of growth hormone (GH) and prolactin (Prl) was studied in rat pituitary cells cultured in monolayer. 12-O-tetradecanoyl phorbol-13-acetate (TPA), the most potent phorbol ester, stimulated GH accumulation in the cultured medium in a dose-dependent manner. TPA also stimulated Prl accumulation. A time course study indicated that TPA mainly stimulates release of GH. The maximal stimulation of GH release by TPA (100 ng/ml) was 3-4-fold over control. Phorbol-12,13-dibutyrate (PDB), another tumour-promoting phorbol ester, stimulated GH release to an extent similar to that of TPA, while a biologically inactive compound, phorbol-12,13-diacetate (PDA), had no effect. TPA-stimulated GH release was not affected by the presence of indomethacin, an inhibitor of prostaglandin (PG) synthesis, indicating that PG is not involved in the process of TPA-stimulated GH release. Co++, a competitive antagonist of Ca++, at 2.0 mM completely suppressed the GH release induced by TPA, and this inhibition was partially reversed by the addition of 2.0 mM Ca++. Verapamil, a Ca++ channel blocker, reduced TPA-stimulated GH release, and trifluoperazine, an inhibitor of Ca-calmodulin formation, had a similar effect. Somatostatin (SRIF) also inhibited the GH release by TPA. These observations are compatible with the idea that Ca++ may be involved in the process of TPA-stimulated GH release. Since TPA has been reported to activate a Ca++- and phospholipid-dependent protein kinase (protein kinase C), it is possible that TPA stimulate GH release by activating the enzyme. Further studies are required to clarify this point.

Animals↗
PubMed1984

Interleukin-2 activity in chronic active liver diseases: response by T cells and in the autologous mixed lymphocyte reaction.

The T cell growth factor, interleukin-2 (IL-2), is a lymphokine which supports the immunoregulatory function of T cells. We measured the production of and response to IL-2 of peripheral blood T cell subsets from patients with chronic active liver diseases (CALD) and other liver diseases (Others) by the proliferative response of the cells activated with phytohaemogglutin P. Both production of and response to IL-2 of T cells from 24 patients with CALD were markedly decreased (P less than 0.001) in comparison with 13 controls. T cells from 10 patients with Others yielded low IL-2 titre (P less than 0.05) and responded to IL-2 in a depressed manner (P less than 0.05). OKT4+ and OKT8+ cells from five CALD patients as well as five controls equally produced IL-2 and responded to it. However, IL-2 production (P less than 0.05) and response to IL-2 (P less than 0.01) of OKT4+ cells from CALD patients were decreased in contrast to those of OKT8+ cells. We also examined the effect of IL-2 on the autologous mixed lymphocyte reaction. A highly significant increase (P less than 0.001) in the proliferative response of OKT8+ cells and unseparated T cells from 15 patients with CALD occurred with the addition of IL-2 although the values were still lower (P less than 0.01) than those of OKT8+ and unseparated T cells from 12 controls. Addition of IL-2 did not result in a significant increase of the reactivity of OKT4+ cells from patients with CALD. These results further delineate the nature of the immunoregulatory aberration in CALD.

Adult↗
PubMed1984

Increased peripheral blood Ia positive T cells and their effect on autologous mixed lymphocyte reaction in chronic active liver disease.

We measured Ia antigen bearing peripheral blood T cells, as an index of immunological stimulation, of patients with chronic active liver diseases (CALD) by the rosette assay method. We also examined the role of Ia antigen which represents the products of the genes of the major histocompatibility complex on the autologous mixed lymphocyte reaction (AMLR) since this reaction may reflect self regulation of immune responses. The percentages of Ia positive T cells of 29 patients with CALD (17.1 +/- 4.3%, P less than 0.001) and of 12 patients with other liver diseases (12.9 +/- 2.4%, P less than 0.05) were increased when compared with that of normal individuals (10.7 +/- 2.0%). However, levels of Ia positive T cells activated by phytohaemagglutinin-P in patients with CALD and other liver diseases did not differ from normal subjects. Ia positive cells in OKT8 positive cells were markedly elevated (P less than 0.001), whereas those in OKT4 positive cells were decreased (P less than 0.01) in CALD. The impaired values for the AMLR correlated inversely (P less than 0.01) with the increased percentages of Ia positive T cells in patients with CALD. Further analysis showed that there was no suppression of the proliferation of Ia and OKT4 positive cells by Ia and OKT8 positive cells although the culture of increasing numbers of Ia and OKT8 positive cells and decreasing numbers of Ia and OKT4 positive cells gave a lesser AMLR value. These data suggest that the increase in Ia positive T cells and the alteration of Ia positive cells in the T cell subsets reflect an activation of immune system and provide further evidence in favour of an abnormality of the immunoregulatory system in CALD.

Adult↗
PubMed1984

[A case of pedunculated hepatoma suspected of adrenal tumor].

We herein report a case of pedunculated hepatoma which was preoperatively diagnosed as nonfunctioning adrenal tumor. A 51-year-old man was admitted for further examination of right hypochondrial pain. CT scan showed a right suprarenal mass. Tumor vessels were visualized on selective right renal arteriography and right inferior phrenic arteriography. Adrenal function was normal. Preoperative diagnosis was nonfunctioning right adrenal tumor. On operation, we found a right suprarenal tumor which was in continuity with the inferior part of the liver. Pathological diagnosis of the biopsy specimen was hepatocellular carcinoma (Edmondson's grade 3). Difficulty of preoperative diagnosis of pedunculated hepatoma is discussed.

Adrenal Gland Neoplasms↗
PubMed1984

Antiulcer actions in rats of new synthetic polyisoprenoids.

The effects of 3-N,N-dimethylaminopropyl farnesyl acetate (DMFA), N'-geranylpiperazinyl farnesyl acetamide (GPFA) and N'-methylpiperazinyl geranylgeranyl acetamide (MPGA) were studied on gastric secretion, gastric bleeding and gastric mucosubstances in rats. DMFA lowered gastric juice and gastric bleeding, and GPFA increased gastric mucosubstances and decreased gastric bleeding. MPGA showed remarkable effects for all of these tests. Consequently it might be said that MPGA is a useful agent against both aggressive and resistant factors on gastric functions.

Alcian Blue↗
PubMed1984

Nifedipine in hypertension and heart failure.

The use of nifedipine in patients with hypertension, heart failure, and acute myocardial infarction is discussed. Data from over a ten-year period are presented. Results indicate that nifedipine, although frequently prescribed as an antianginal agent, is also useful as an antihypertensive agent, especially when used concomitantly with other drugs. Its ability to cause fluctuations in blood pressure remains a shortcoming, however.

Adult↗
PubMed1983

Identification of lactoferrin as an essential growth factor for human lymphocytic cell lines in serum-free medium.

A serum-free medium supplemented with growth factor(s) was devised to grow human lymphocytic cell lines. The medium was developed using human lymphocytic cell line, Bri 7 cells. In the process of constructing the medium, human lactoferrin was found to be an essential growth factor for the cell line. Human lactoferrin has higher growth stimulatory activity than human transferrin, and was sensitive to heat. Long-term cultivation of the cells was achieved in the defined medium supplemented with human lactoferrin only. The defined medium specifically supported the growth of various other human B- and T-lymphocytic cell lines but not the growth of various mouse lymphocytic cell lines. In lactoferrin-supplemented medium, the growth of some human cell lines were further stimulated by the addition of a combination of insulin, ethanolamine and selenium, or another combination of 2-mercaptoethanol and the above three factors. Bovine lactoferrin could be substituted for human lactoferrin.

Animals↗
PubMed1983

Immunoprecipitation of 125I-insulin crosslinked receptor.

125I-insulin was covalently crosslinked to its receptor on human placental membrane fractions with disuccinimidyl suberate. The 125I-insulin crosslinked receptor was solubilized with Triton X-100 and used as a probe to determine autoantibodies to the insulin receptor in sera from patients with insulin resistance (type B syndrome). When the solubilized 125I-insulin: receptor complex was incubated with these sera and then with anti-human IgG serum, the complex was precipitated as a function of the amount of anti-receptor serum. Unlabelled insulin at concentrations less than or equal to 10 micrograms/ml did not affect immunoprecipitation of the complex, suggesting that a subpopulation of anti-receptor antibodies recognizes determinants outside the insulin binding region of the receptor molecule. 125I-insulin: receptor complex was precipitated also by the addition of anti-insulin antibodies. The effect of anti-insulin antibody was eliminated by the addition of excess unlabelled insulin. The immunoprecipitation assay using 125I-insulin crosslinked receptor was sensitive and convenient for detecting anti-receptor antibodies.

Cell Membrane↗