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Biomedical subjects

M Arisawa

Publications and source records attributed to M Arisawa.

At least 127 records · Page 7Linked to original sources
PubMed1989

A cytotoxic constituent of Lysimachia japonica THUNB. (Primulaceae) and the structure-activity relationships of related compounds.

A cytotoxic alkylresorcinol was isolated from Lysimachia japonica THUNB. (Primulaceae) and identified as grevillol (2). It was tested for cytotoxicity against KB, B-16, PC-13, L-5178Y, P-388, and HEp-2 cells in vitro. Synthetic related compounds were also tested for cytotoxicity against the KB cell line, and the structure-activity relationships are discussed.

Cell Survival↗
PubMed1989

Studies on aldose reductase inhibitors from natural products. II. Active components of a Paraguayan crude drug "Para-parai mí," Phyllanthus niruri.

Aldose reductase (AR) inhibitory activity-directed fractionation of the 70% ethanolic extract of Para-parai mí, Phyllanthus niruri, has led to the isolation of three active components, ellagic acid (1), brevifolin carboxylic acid (4) and ethyl brevifolin carboxylate (5). Among them, 1 showed the highest inhibitory activity, being about 6 times more potent than quercitrin, which is a known natural inhibitor of AR.

Aldehyde Reductase↗
PubMed1989

Characterization of calcitonin gene-related peptide (CGRP) receptors in guinea pig lung.

Receptors for calcitonin gene-related peptide (CGRP) in the lung membranes of guinea pig were characterized by using a millititer plate precoated with polyethylenimine. Specific binding of 125I-CGRP was time-dependent, rapid, and reversible, and the binding increased linearly with increasing concentrations of membrane protein. Scatchard analysis revealed two classes of CGRP binding sites: high affinity sites with a KD value of 7.17 x 10(-11) M and a Bmax of 364 fmol/mg protein and low affinity sites with a KD value of 1.7 x 10(-8) M and a Bmax of 39594 fmol/mg protein. Furthermore, the specific binding of 125I-CGRP was dissociated in the presence of GTP or Gpp(NH)p, suggesting that CGRP receptors in guinea pig lung membranes were coupled to the guanine nucleotide regulatory protein. Scatchard analysis of CGRP binding in the presence of GTP revealed selective inhibition of the binding to high affinity binding sites. Unlabeled CGRP displaced the binding of 125I-CGRP to guinea pig lung membranes with an IC50 value of 3.1 x 10(-10) M. In contrast, salmon calcitonin and human calcitonin displaced the binding at 600-fold higher concentrations. We suggest that both low and high affinity binding sites for CGRP exist in the lung membranes of the guinea pig, and the high affinity binding sites for CGRP may be coupled to GTP binding regulatory protein.

Animals↗
PubMed1989

Effect of estrogen on the response of thyroid stimulating hormone to substance P in rats.

The role of substance P (SP) in the control of thyroid stimulating hormone (TSH) release and the influence of gonadal steroid were investigated. Intravenous administration of SP failed to alter plasma levels of TSH in ovariectomized (OVX) rats, whereas SP induced a significant increase in plasma TSH in estradiol benzoate-primed (Eb-primed) OVX rats (P less than 0.001). Further, intravenously administered SP did not affect the plasma TSH concentration in normal male rats, but significantly increased it in Eb-primed castrated male rats (P less than 0.01). These data suggest possible roles for SP at the level of the hypothalamus and/or the pituitary gland in stimulating TSH secretion under the influence of estrogen.

Animals↗
PubMed1989

Inhibition of natural killer activity by calcitonin gene-related peptide.

The effect of calcitonin gene-related peptide (CGRP) on natural killer (NK) cell activity in spleen cells from Balb/c mice and nude mice was studied. CGRP dose-dependently (10(-9) to 10(-7) M) inhibited NK activity of spleen cells from both strains of mice. This inhibitory effect was observed at the effector to target ratios of 12.5:1 to 100:1. Maximum inhibition by 10(-7) M CGRP was about 60%. The inhibition of NK activity by CGRP was also observed in anti-Thy 1.2 plus complement treated Balb/c spleen cells. Furthermore, when cells were treated with 10(-9) to 10(-7) M CGRP the concentration of intracellular cyclic AMP increased in spleen cells of nude mice. The characteristics of these cells were similar to those of NK cells, (1) being petri dish and nylon wool nonadherent, (2) expressing asialo GM1 antigen, and (3) lacking readily detectable Thy 1 antigen and immunoglobulin. In addition, the intravenous injection of asialo GM1 completely abolished NK activity in spleen cells from nude mice and the increase in intracellular cyclic AMP in spleen cells by CGRP was less in spleen cells from mice given an anti-asialo GM1 injection. Our present study suggests that CGRP inhibits NK cell activity by increasing the intracellular cyclic AMP concentration. CGRP may be implicated in the regulation of NK function.

Animals↗
PubMed1988

Inhibition of mitogen-stimulated T lymphocyte proliferation by calcitonin gene-related peptide.

The effect of calcitonin gene-related peptide (CGRP) on mouse lymphocyte proliferation stimulated by mitogens was studied. CGRP (10(-10)-10(-7) M) dose-dependently inhibited the proliferative response of mouse lymph node cells and spleen cells stimulated by T cell mitogens concanavalin A (Con A) and phytohemagglutinin (PHA), whereas a B cell mitogen lipopolysaccharide (LPS) did not inhibit this response. The maximal inhibition by this peptide was 50% to 80% at 10(-8) and 10(-7) M. The addition of 10(-8) and 10(-7) M CGRP to lymph node cell cultures 24 hr after stimulation with Con A or PHA also had a significant inhibitory effect on the proliferative response. Furthermore, in the same concentration range (10(-10)-10(-7) M) CGRP increased intracellular cyclic AMP concentration in nylon wool nonadherent cells, but not in nylon wool adherent cells. CGRP had no significant effect on intracellular cyclic GMP concentration. In addition, specific binding of CGRP was observed in mouse spleen cells. Our present study suggests that CGRP inhibits the proliferative response of T lymphocytes to the mitogens by interacting with cell receptors coupled with adenylate cyclase. CGRP may be implicated in the regulation of T cell function.

Animals↗
PubMed1985

Growth inhibitory, insecticidal and antifeedant effects of some antileukemic and cytotoxic quassinoids on two species of agricultural pests.

Several quassinoids, obtained by isolation and derivatization from Simaba multiflora and Soulamea soulameoides, were evaluated for growth inhibitory and insecticidal effects against the tobacco budworm (Heliothis virescens) and for antifeedant effects against H. virescens and the fall armyworm (Spodoptera frugiperda). The relative activity of the quassinoids as insect growth inhibitors generally paralleled their known relative potency as antileukemic and cytotoxic agents.

Animals↗