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Biomedical subjects

S Oikawa

Publications and source records attributed to S Oikawa.

At least 235 records · Page 13Linked to original sources
PubMed1987

Host-mediated antitumor effect of grifolan NMF-5N, a polysaccharide obtained from Grifola frondosa.

The antitumor mechanism of grifolan NMF-5N, a beta-1,3-glucan obtained from mycelia of Grifola frondosa, was examined. Grifolan NMF-5N did not show direct cytocidal effect on cultured tumor cells. However, intraperitoneal injection of grifolan NMF-5N increased the number of peritoneal exudate cells and peritoneal adherent cells which showed cytostatic activity towards syngeneic tumor cells. In an in vivo assay, the administration of carrageenan, an inhibitor of macrophage function, reduced the antitumor activity of grifolan NMF-5N. The delayed-type hypersensitivity reaction was augmented in the grifolan NMF-5N-administered mice. The administration of NMF-5N augmented the induction of cytotoxic T cells but the antitumor activity of grifolan NMF-5N was reduced in athymic nu/nu mice. In addition, the treatment with anti-Thy 1,2 antibody and complement C' of spleen cells taken from mice which showed regression of tumor due to grifolan NMF-5N, reduced the neutralizing effect in Winn assay. These results suggested that grifolan NMF-5N shows antitumor activity via host-mediated mechanisms and both macrophages and T cells play important roles in the mechanisms.

Animals↗
PubMed1987

Antitumor effect of polysaccharide grifolan NMF-5N on syngeneic tumor in mice.

Antitumor activity of grifolan NMF-5N, a beta-1,3-glucan obtained from mycelia of Grifola frondosa, was examined. Grifolan NMF-5N showed antitumor activities in allogeneic and syngeneic murine tumor systems. In the allogeneic tumor system, a potent antitumor activity over 95% was observed against the solid form of sarcoma 180 when grifolan NMF-5N was injected intraperitoneally (i.p.) at 25-200 micrograms/mouse daily for 10 successive days. In the syngeneic tumor systems, significant antitumor activities were observed against Meth A fibrosarcoma and MM 46 carcinoma by injection at 100 micrograms/mouse daily for 5 successive days, especially i.p. injection at day 7-11, when the tumor cells were inoculated subcutaneously (s.c.) on day 0. Moreover, when grifolan NMF-5N was injected i.p. every other week, significant antitumor activity was also observed. In addition, a single treatment with grifolan NMF-5N at 500 micrograms/mouse showed antitumor activities. Grifolan NMF-5N exhibited antitumor activities against these two syngeneic tumors by intraveneous (i.v.) injection. However, a marked inhibitory activity was observed by intratumorous (i.t.) injection against Meth A fibrosarcoma but not against MM46 carcinoma. These results suggest that antitumor activities of grifolan NMF-5N in murine syngeneic tumor systems depend on not only dosage but also injection routes and timing.

Animals↗
PubMed1987

Effects of chronic propranolol treatment on hepatic adenylate cyclase system in the rat.

The biochemical aspects of hepatic beta-adrenergic receptors and adenylate cyclase activity in male adult rats were examined during chronic treatment of a beta-adrenergic antagonist, propranolol. The blockade of beta-adrenergic nervous systems for 7 to 10 days produced a considerable elevation of basal, glucagon, sodium fluoride, and 5'-guanylylimidodiphosphate, Gpp (NH)p-stimulated enzyme activity with a negligible response to a beta-adrenergic agonist, isoproterenol. There was no alteration in the density or the affinity of beta-adrenergic receptors for the agonist during the treatment. Guanine nucleotides have failed to induce a transformation of the higher affinity to the lower affinity state of beta-adrenergic receptors of the hepatic membrane derived either from control or the propranolol-treated animals. The activity of stimulatory guanine nucleotide regulatory proteins (Ns) in the enzyme, assessed by ADP-ribosylation was also not altered by the antagonist. These results suggest that the mechanism of the observed sensitization of adenylate cyclase induced by chronic beta-adrenergic blockade involves facilitation of Ns interaction with the catalytic subunit of the enzyme with no change in the beta-adrenergic receptor functions.

Adenosine Diphosphate↗
PubMed1986

Glucosamine 6-phosphate acetylase in rat ascites hepatomas.

The fetal type enzyme pattern of glucosamine 6-phosphate acetylase (glucosamine-phosphate acetyltransferase, EC 2.3.1.4) was present in rat ascites hepatomas. The levels of acid-soluble and protein-bound amino sugars in the hepatomas were determined.

Acetyltransferases↗
PubMed1986

Antitumor activity of a beta-1,3-glucan obtained from liquid cultured mycelium of Grifola frondosa.

The antitumor activity of a branched beta-1,3-glucan "grifolan LE" purified from liquid cultures of Grifola frondosa (Ohno et al. Chem. Pharm. Bull., 34, 1709-1715 (1986] was examined on an allogeneic murine tumor system. By intraperitoneal (i.p.) administration (100-200 micrograms/mouse/d X 5) at days 1 to 9 from the tumor transplantation, grifolan LE showed marked inhibitory activity on the growth of solid form sarcoma 180 in ICR mice. Significant activity was also observed in intravenous (i.v.) or intratumoral (i.t.) administrations. However, the oral (p.o.) administration of grifolan LE was not effective. I.p. administration of grifolan LE at a dose of 100 micrograms/mouse/d X 5 before the tumor transplantation showed significant inhibition of tumor growth. I.p. administration of grifolan LE at day +11 to +19 was also effective. Grifolan LE was not effective on the ascites form of sarcoma 180. The pretreatment of sarcoma 180 cell with grifolan LE in vitro did not affect tumor growth. The mice cured from the solid form of sarcoma 180 by administration of grifolan LE had the ability to reject the same tumor cell. From these results, it is suggested that the antitumor activity of grifolan LE occurred by modification of biological responses.

Animals↗
PubMed1985

Structure of dog and rabbit precursors of atrial natriuretic polypeptides deduced from nucleotide sequence of cloned cDNA.

The structure of precursors of dog and rabbit atrial natriuretic polypeptides was determined by nucleotide sequence analysis of cloned cDNA of mRNA encoding the peptides. The dog and rabbit precursors are 149 and 153 residues long having 23- and 25-residue putative signal peptides at their N-termini respectively. The 28-residue peptide with identical sequence to that of human, which has potent natriuretic activity, is located at the C-terminus of the dog precursor. The 28-residue peptide of identical sequence to that of mouse/rat is located at C-terminus of rabbit precursor followed by additional Arg-Arg sequence which is also found in rat/mouse precursors and is apparently removed during processing.

Amino Acid Sequence↗