Biomedical subjects

I F Tannock

Publications and source records attributed to I F Tannock.

143 records · Page 8Linked to original sources

PubMed1983

Activity of mitomycin C for aerobic and hypoxic cells in vitro and in vivo.

We have observed the selective toxicity of mitomycin C toward hypoxic as compared to aerobic cells in vitro for three established cell lines (Chinese hamster ovary, Chinese hamster V-79, and human HeLa) and for cells from the transplantable KHT murine tumor. The magnitude of the selective toxicity was cell line dependent. We have studied the in vivo effects of mitomycin C against aerobic and hypoxic cells of two transplantable murine tumors: the KHT fibrosarcoma and the 16/C mammary carcinoma. Either mitomycin C was given with radiation to kill most of the aerobic cells, or it was given alone. Endpoints of response were cell survival assessed by lung colony assay for the KHT tumor, and growth delay for the 16/C tumor. In some experiments, mitomycin C appeared more effective when used with radiation than when used alone, but the results of combined treatment fell just within the range of additivity as defined by isobologram analysis. The effects of combined treatment were independent of the order in which drug and radiation were given. Mitomycin C was also used in combination with Adriamycin to treat the 16/C tumor, since we have found previously that Adriamycin spares hypoxic cells in this tumor. In three of four experiments, combined drug effects were slightly greater than predicted by an additive relationship. We conclude that mitomycin C is active against hypoxic cells in two murine tumors, but that it has at most minor specificity for hypoxic as compared to aerobic cells in vivo.

Aerobiosis↗

PubMed1980

Chemotherapy for adenocystic carcinoma.

Seventeen patients with adenocystic carcinoma have received 34 adequate trials of chemotherapy at Princess Margaret Hospital since 1969. There have been five objective responses to chemotherapy in 4 cases, lasting from five to 24 months, and 3 other patients have had stabilized disease for a period of five to seven months. Responding and stabilized patients all had symptomatic improvement. Most responses were to 5-fluorouracil, the preferred drug for initial treatment of metastatic disease or locoregional disease that cannot be controlled by means of surgery or radiation therapy.

Alkylating Agents↗

PubMed1980

In vivo interaction of anti-cancer drugs with misonidazole or metronidazole: methotrexate, 5-fluorouracil and adriamycin.

I have studied the effects on growth of two tumours in mice and on host toxicity, of combining Misonidazole (MISO) or Metronidazole (METRO) with Methotrexate (MTX)-5-fluorouracil (FU) or Adriamycin (ADR). The nitroimidazoles alone had no effect on the growth of either tumour, but MISO (1 mg/g) led to a small increase in delay to regrowth of the 16/C mammary carcinoma but not the KHT fibrosarcoma, when given after X-irradiation. MTX was active only against the KHT tumour, and growth delay was not increased by the addition of MISO or METRO. FU delayed growth of both tumours, and growth delay was increased slightly by single-dose MISO. ADR was active only against the 16/C tumour, and delay to regrowth was increased by adding MISO. Host toxicity assessed by death and loss of body weight was much greater when MISO or METRO were added to MTX, and a little greater when they were added to FU. ADR plus MISO caused no deaths and no greater loss of body weight than ADR alone. The addition of MISO to treatment with anticancer drugs led to a slightly greater and more prolonged myelosuppression. METRO and MISO increase the anti-tumour effects of some anti-cancer drugs, but may also increase host toxicity. Nitroimidazoles should be used with caution in combination with chemotherapy.

Animals↗

PubMed1980

In vivo interaction of anti-cancer drugs with misonidazole or metronidazole: cyclophosphamide and BCNU.

The addition of misonidazole (MISO) or metronidazole (METRO) to treatment with cyclophosphamide (CY) increased delay to regrowth of 2 experimental tumours. The effect was observed for large an small tumours, was present for doses of MISO that are ineffective for killing hypoxic cells, and required that it be given with, or shortly before CY. Mice receiving combined treatment had more weight loss and myelosuppression than those receiving CY alone, and the Therapeutic Index was lower. MISO caused a marked increase in growth delay when combined with BCNU to treat the KHT sarcoma. This effect was observed for small and large tumours, required simultaneous administration of drugs, and also led to increased host toxicity. There was no therapeutic advantage from combined treatment. Survival of aerobic or anoxic Chinese hamster ovary (CHO) cells was assessed after exposure in vitro to serum from mice that had received CY or BCNU alone. MISO alone, or combined treatment. Results of these experiments suggest that (1) MISO delays the excretion or breakdown of active metabolites of CY, and (2) at a dose that does not kill hypoxic cells, it may selectively "sensitize" hypoxic cells (but not aerobic cells) to the action of BCNU. The presence of other undetermined interactions of BCNU and MISO is inferred from the increased toxicity to (aerobic) normal tissue. Misonidazole or metronidazole should be used with caution in patients who are receiving BCNU or cyclophosphamide.

Animals↗

PubMed1979