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Biomedical subjects

M Urano

Publications and source records attributed to M Urano.

At least 109 records · Page 6Linked to original sources
PubMed1978

Enhancement by Corynebacterium parvum of the normal and tumor tissue response to hyperthermia.

The effect of Corynebacterium parvum treatment on the response of tumor and normal tissue to hyperthermia (43.5 degrees) was studied. Animals were C3Hf/Sed mice from our defined flora mouse colony. The time at hyperthermia that achieved control of one-half of methylcholanthrene-induced fibrosarcomas and the foot reaction were examined after treatment. C. parvum, if given 3 to 32 days before hyperthermia, enhanced the reaction to local hyperthermia of normal tissue. No enhancement was observed if C. parvum was given after hyperthermia. This enhancement was more dramatic for tumor response resulting in a therapeutic gain factor of congruent to 2.3 (3.7/1.6). Comparative studies on combined Corynebacterium and radiation failed to demonstrate the enhancement to normal tissue.

Animals↗
PubMed1978

Cytocidal and cytostatic ability of Corynebacterium liquefaciens in mouse squamous cell carcinoma in vivo.

The cytostatic and cytocidal action of Corynebacterium liquefaciens was studied in a mouse squamous cell carcinoma in vivo. Kinetic analysis of tumor cells 4 and 8 days after a single i.p. dose of 2.0 mg C. liquefaciens showed a marked prolongation of the mean cell generation time (TG). This prolongation affected most the G1 and, to a lesser extent, the S phases of the cell cycle. The tumor growth factor was decreased, and the mean value of the cell loss factor was increased. Assays to determine the number of tumor cells needed to produce the tumor in one-half of the transplant recipients showed that peritoneal exudate cells collected from mice given injections of C. liquefaciens exerted tumor cell killing that depended on the peritoneal exudate cell tumor:cell ratio. This cell killing was not found with peritoneal exudate cells from normal or proteose peptone-treated mice.

Animals↗
PubMed1978

Repair of potentially lethal damage after single injection or continuous infusion of bleomycin.

The repair of potentially lethal damage after administration of bleomycin by a single injection or by continuous infusion was studied in vivo. Experimental tumors were the fifth generation isotransplants of a squamous cell carcinoma which arose spontaneously in a C3Hf/He female mouse. Bleomycin was administered intraperitoneally by a single injection or by 24-hr continuous infusion. Cell survival was assayed by TD50 method. Dose-survival curve after a single injection exhibited a biphasic or upward concave curve. Surviving fraction increased rapidly if tumors were left in situ after treatment and reached a plateau at 5 hr, indicating that tumor cells were able to repair the potentially lethal damage induced by bleomycin. Dose-survival curve after continuous infusion was also biphasic, but had a small shoulder. The repair of potentially lethal damage was slight, if any, when tumors remained in situ for 6 hr after the end of 24-hr continuous infusion. This indicates that potentially lethal damage was being repaired during drug infusion.

Animals↗
PubMed1977

Effect of corynebacterium liquefaciens on a C3Hf mouse squamous cell carcinoma.

The antitumor effect of anaerobic Corynebacterium liquefaciens was compared with that of specific immunization. Experimental tumors were fourth or fifth generation isotransplants of a NR-Sl squamous cell carcinoma that arose spontaneously in a C3Hf/He female mouse. Specific immunization failed to exhibit an antitumor effect, whereas a single administration of the bacterium markedly inhibited the growth of the tumor. This growth inhibition was most effective when C. liquefaciens was administered 2 to 4 days before transplantation of tumor cells, but marked inhibition was also observed when this agent was administered after transplantation. The inhibitory effect was independent of dose within a range of 0.1 to 2.0 mg/mouse; a single dose of less than 0.05 mg/mouse did not exhibit antitumor effect. Multiple administrations of large doses, if given with short treatment intervals, were no more effective than one small dose. Multiple doses given at 14-day intervals resulted in marked growth retardation. The dose of cells that produced 50% tumor takes in C. liquefaciens-treated animals was not significantly different from that in nontreated animals, indicating that this bacterium exhibited no lethal effect on the tumor cells studied.

Animals↗
PubMed1976

Effect of PS-K, a protein polysaccharide, on pulmonary metastases of a C3H mouse squamous cell carcinoma.

We studied the effects of PS-K, a protein polysaccaride isolated from a basidiomycete, on the formation of blood-borne metastases. Experimental tumors were fifth-generation isotransplants of a spontaneous C3Hf mouse squamous cell carcinoma that was weakly antigenic. A single-cell suspension from fourth generation tumors was transplanted, and the tumor-bearing legs of the mice were amputated when transplants reached a certain diameter. Daily administrations of PS-K followed immediately, and both lungs were excised on the 21st postamputation day. The number of lung colonies formed on the surfaces of both lungs was counted and total volumes of metastatic colonies were estimated. PS-K, if administered alone, did not inhibit the lung colony formation. Marked reduction in this formation was observed when five daily doses of PS-K were administered simultaneously with cyclophosphamide. These observations indicate that PS-K may be a potent agent in the therapy of cancer if used as an adjuvant to a chemotherapeutic agent.

Animals↗
PubMed1976

Repair of potentially lethal radiation damage in acute and chronically hypoxic tumor cells in vivo.

The ability of animal tumor cells to repair potentially lethat damage was studied in vivo. Fifth-generation isotransplants of a spontaneous mouse squamous-cell carcinoma were irradiated under tourniquet-induced hypoxia or in air. Tumors were removed either immediately or 6 hours after irradiation and dose-response curves were determined by TD50 assays. Repair was attributed to cells in the hypoxic cell component for animals irradiated in air. Extensive repair was also noted for those irradiated under typoxic conditions. Implications of these results are discussed.

Animals↗
PubMed1976

[Effect of continuous bleomycin treatment and of oil-suspended bleomycin on experimental tumor growth (author's transl)].

Effects of continuous administration of bleomycin solution and of intralesional injection of sesame oil-suspended bleomycin on tumor growth were studied. Experimental animal tumors were 3 rd generation isotransplants of a spontaneous C3H mouse mammary carcinoma. Bleomycin treatments were started when transplanted tumors reached 8 mm in diameter and the measurement of tumor volume was followed. Dose administered was fixed as 100 mg/kg in all the groups. Bleomycin solution was given intralesionally in a single or 4 daily doses, or intraperitoneally by continuous infusion. The latter method inhibited tumor growth most effectively, while the single injection was the last effective. Intralesional injection of oil-suspended exhibited similar effectiveness as the continuous infusion, and it was independent of the number of fractions. These results were interpreted by the several features in the response of mammalian cells to the antibiotic.

Animals↗
PubMed1976

Combined use of bleomycin in radiotherapy of a mouse mammary carcinoma.

Experiments were carried out to determine TCD50 (50% tumor control dose) of 3rd generation isotransplants of a C3H mouse mammary carcinoma treated or not treated with Bleomycin. If the antibiotic was injected 30 min before a single X-ray dose, TCD50 was reduced. This reduction in TCD50 was independent of Bleomycin dose of more than 15 mg/kg, because of the upward-concave nature of Bleomycin dose-cell survival curve. The combined effect, when tested by TCD50 assays, appeared less than additive. This effect was further examined by a series of TD50 assays which revealed that these tumor cells were capable of repairing the potentially lethal damage induced by X-rays and that induced by Bleomycin. It was also found that the potentially lethal damage after combined X-ray and Bleomycin treatments was repaired. These findings indicated that the combined X-ray and Bleomycin treatment resulted in additive effect if the repair of potentially lethal damage in tumor cells were taken into account.

Animals↗
PubMed1975

Optimum fractionation regimen for bleomycin treatment.

A theoretical analysis was made on the optimum Bleomycin treatment regimen on the basis of the "binding-saturation model" which was proposed for the Bleomycin dose-cell survival relation. The surviving fraction of tumor cells decreased as a function of the number of fractionated treatments up to the optimum fractionation number if the tumor was treated with the same total dose. The effect of cellular sensitivity to the antibiotic, tumor doubling time, treatment interval, and total doses on the optimum regimen was analyzed. The importance of treatment interval and tumor doubling time was emphasized and the short treatment interval was recommended for the clinical use of this antibiotic. The optimum number of fractions increased linearly with the increase of the total dose while the optimum single dose was independent of the total dose. A concept of the tumor control probability of tumors treated with the optimum fractionation regimen was introduced and implications of these analyses in the clinical cancer chemotherapy were discussed.

Bleomycin↗