T Hosokawa

The University of Tokyo, Tōkyō, Japan

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Publications (8)23.55 Total impact

  • Acta Crystallographica Section C Crystal Structure Communications 01/1991; 47(3):684-686. · 0.78 Impact Factor
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    ABSTRACT: Ascofuranone demonstrated antitumor activity against FM3A murine mammary carcinoma, implanted in the peritoneal cavity of syngeneic mice, C3H/He. It was more effective by treatment prior to implantation than by that after implantation. Treatment with ascofuranone also increased splenic cytotoxicity and phagocytic activity of host animal cells. Moreover, ascofuranone induced inflammatory cells in the peritoneal cavity which are mainly composed of polymorphonuclear leukocytes and macrophages. These cells are more potent in cytotoxicity against FM3A cells than with resident peritoneal cells. The antitumor activity of ascofuranone was suppressed by ip administration of silica, just prior to tumor implantation. These results suggest that the prophylactic antitumor activity of ascofuranone is expressed through the activation of phagocytes. Ascofuranone also suppressed pulmonary metastasis of B16 melanoma and Lewis lung carcinoma. Treatment after tumor implantation failed to suppress the metastasis. Single treatment of ascofuranone 4 days prior to implantation decreased the metastasis of Lewis lung carcinoma but not that of B16, whereas single treatment of ascofuranone 24 hours prior to the tumor implantation decreased the metastasis of B16 but not that of Lewis lung carcinoma.
    The Journal of Antibiotics 08/1988; 41(7):959-65. · 2.19 Impact Factor
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    ABSTRACT: Ehrlich ascites carcinoma-bearing mice exhibit hypertriglyceridemia. An antitumor antibiotic, ascofuranone, suppressed tumor-induced hypertriglyceridemia when administered i.p. even when no evident antitumor activity was observed without affecting the levels of free fatty acids, phospholipids, cholesterol, glucose, and total protein in plasma. Ascofuranone did not reduce plasma triglycerides of normal mice. Insulin and clofibrate, known modifiers of lipid metabolism, showed no significant suppression. Ascofuranone is also effective on solid tumor-induced hypertriglyceridemia. Another notable change of metabolism affected by tumor-bearing in the early stage where hypertriglyceridemia has not yet fully progressed is hypoglycemia. Although ascofuranone did not affect hypoglycemia, the suppressive effect on hypertriglyceridemia was more evident when ascofuranone was administered in the early stage than in the later stage. These results suggest that ascofuranone suppresses hypertriglyceridemia by specifically affecting the changes of host metabolism which is induced in the early stage of tumor bearing.
    Cancer Research 02/1987; 47(1):96-9. · 8.65 Impact Factor
  • J Magae, T Hosokawa, K Ando, K Nagai, G Tamura
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    ABSTRACT: Ascofuranone (AF) showed an antitumor protective effect on L-1210 leukemia when AF was administered once 7 days before tumor challenge. However, effect was not elicited when host mice were treated with AF simultaneously with tumor challenge. AF pretreatment on day 7, 5 and 3 before tumor challenge protected the host from the ascites form of S-180. AF also retarded tumor growth when administered once daily for 5 consecutive days 24 hours after transplantation, but antitumor effect was not seen with combined treatments before and after the transplantation. Similar results were noted with Ehrlich ascites carcinoma. AF treatment of normal mice enlarged the solid lymphoid organs without affecting body weight gain. The splenocytes derived from AF-treated mice lowered mitogenic response to phytohemagglutinin, while the mitogenic response to concanavalin A and lipopolysaccharide was unaffected.
    The Journal of Antibiotics 12/1982; 35(11):1547-52. · 2.19 Impact Factor
  • T Hosokawa, M Sawada, K Ando, G Tamura
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    ABSTRACT: The effect of 4-O-methylascochlorin (MAC), an experimental hypocholesterolemic agent, on cholesterol metabolism was investigated in rats in two separate experiments. The administration of MAC for 2 and 6 consecutive weeks at daily doses of 100-135 mg/kg resulted in reduction in serum cholesterol levels of 16% after 2 weeks of treatment in the first experiment, and 13% after 6 weeks in the second experiment in comparison to the corresponding controls. MAC administered at a daily dose of 100 mg/kg for 2 weeks showed a significant increase in the biliary excretion of bile acids and cholesterol in bile-duct cannulated rats with or without the administration of taurocholate. In the second experiment, MAC treatment for 6 weeks produced a marked increase in the fecal output of acidic sterols during a 2 to 6-week period. MAC treatment also further enhanced hepatic cholesterol 7 alpha-hydroxylase in the rats. Therefore, it appears that the mechanism of serum cholesterol lowering due to MAC is related to the enhancement of hepatic bile acid synthesis and the increase in biliary and fecal excretion of bile acids.
    Lipids 07/1981; 16(6):433-8. · 2.56 Impact Factor
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    ABSTRACT: When deoxycorticosterone acetate (DOCA)-loaded uninephrectomized rats were fed on standard laboratory pellet diet and 1% saline for 5 weeks, caloric homeostasis became abnormal resulting in (a) hyperlipidemia, (b) cholesterol deposit in the heart, (c) significant reduction of triglycerides in the aorta, heart and liver and (d) a 60% increase in the cardiac free fatty acids (FFA) on one hand and a 50% reduction of the hepatic FFA on the other. These facts suggest that the hypertension severely reduces hepatic lipogenesis, whereas the cardiovascular system depends much more on FFA as a metabolic fuel than on glucose. This idea is supported by the deficiency in total body potassium (K) and decrease in serum immunoreactive insulin (IRI) which occur in the hypertension. These alterations were attenuated by the fungal prenylphenols, 4-0-methylascochlorin (MAC) and ascofuranone (AF). The protective effect seems to be partly attributable to the counteraction to DOCA. In addition, the agents caused a specific increase of renal water reabsorption. MAC treatment resulted in a particularly marked reduction of saline intake and excretion of unusually thick urine with 2.8 times higher sodium (Na) concentration than in the DOCA/saline control rats.
    European Journal of Pharmacology 03/1981; 69(4):429-38. · 2.59 Impact Factor
  • M Sawada, T Hosokawa, T Okutomi, K Ando
    The Journal of Antibiotics 12/1973; 26(11):681-6. · 2.19 Impact Factor
  • Tetrahedron Letters 13(25):2541–2544. · 2.40 Impact Factor