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Biomedical subjects

T H Corbett

Publications and source records attributed to T H Corbett.

100 records · Page 6Linked to original sources
PubMedDate not supplied

Preclinical antitumor activity of XK469 (NSC 656889).

XK469 (NSC 656889) is a water-soluble member of the novel quinoxaline family of antitumor agents. In vitro, XK469 demonstrated selective cytotoxicity for several murine solid tumors including colorectal and mammary adenocarcinoma cell lines, when compared to both leukemia and normal epithelial cells. In vivo, XK469 was active against 7/7 murine tumors tested, including pancreatic ductal carcinomas #02 and #03, colon adenocarcinomas #38 and #51/A, mammary adenocarcinoma #16/C and the Adriamycin resistant mammary adenocarcinomas #16/C/ADR and #17/ADR. XK469 was efficacious both intravenously and orally. Regardless of dosing schedule, conventional mice tolerated higher total doses than SCID or nu/nu mice did. Despite these reduced doses, XK469 was active against xenografts of 4/6 human tumor lines including mammary adenocarcinoma MX-1, the small cell lung cancer DMS 273, the prostate model LNCaP and the CNS tumor SF295. The lower doses in the xenograft studies were below curative levels. The dose-limiting toxicity appeared to be myelosuppression with rapid host recovery (5-8 days), and in vitro assays of XK469 toxicity to murine bone marrow neutrophil progenitors CFU-GM (colony forming unit-granulocyte/macrophage) demonstrated concentration-dependent toxicity from 0.5-30 microg/mL. The difference in drug tolerance between BDF1 and SCID mice was detected in vitro as a 3-fold difference in the IC90 for CFU-GM, despite similar IC50 values. Comparative in vitro hematotoxicology studies revealed that human bone marrow CFU-GM tolerated XK469 as well as their SCID counterparts (IC90 values 5.7 vs. 7.4 microg/mL). Based on comparison with previously tested anti-cancer agents, these data suggest that humans will be able to tolerate XK469 doses that are efficacious against human tumor xenografts.

Animals↗
PubMedDate not supplied

cis-Dichlorodiammineplatinum(II): combination chemotherapy and cross-resistance studies with tumors of mice.

cis-Dichlorodiammineplatinum(II) (cis-platinum) has no more than additive, and often much less than additive, lethal toxicity for mice when given in combination with other anticancer agents representing several of the major functional classes of clinically useful anticancer drugs. The previously reported broad spectrum of anticancer activity of cis-platinum against tumors in laboratory animals has now been extended to promisingly useful therapeutic synergism in combination with other active anticancer drugs, including advanced-staged tumors in mice; eg, cis-platinum plus cyclophosphamide against advanced Ridgway osteogenic sarcoma and advanced P388 leukemia, and as surgical adjuvant chemotherapy against advanced colon tumor 26; cis-platinum plus Adriamycin against advanced P388; and cis-platinum plus VP-16-213 against advanced P388. Therapeutic synergism was also seen with cis-platinum plus carminomycin (an Adriamycin analog) against early colon tumor 26. Resistance and cross-resistance studies using sublines of L1210 and P388 selected for resistance to various alkylating agents (cyclophosphamide, melphalan, BCNU, or cis-platinum) indicate a variety of resistance and cross-resistance patterns which further support the growing body of evidence that wide differences in mechanism of cytotoxic activity exist among alkylating agents having experimentally and clinically useful anticancer activity. These data support the observed therapeutic synergisms with combinations of alkylating agents seen against a broad spectrum of murine tumors, and they suggest other drug combinations that might be considered for experimental and clinical trial based on a growing number of logical differences in biochemical mechanism of action of alkylating agent anticancer drugs that have been reported.

Animals↗
PubMedDate not supplied

A test of the carcinogenicity of enflurane, isoflurane, halothane, methoxyflurane, and nitrous oxide in mice.

We exposed Swiss ICR mice for 2-hour periods to 1/32, 1/8 and/or 1/2 MAC enflurane, halothane, isoflurane, methoxyflurane, or N2O both in utero during the last 1/2 of pregnancy (4 exposures at 2-day intervals) and after delivery (24 exposures at 2-to-3-day intervals). Anesthetics were delivered in air or in O2. Thus, 1973 mice were exposed and examined after 15 months of life for the development of neoplastic lesions. Neoplastic lesions (principally pulmonary adenomas, lymphomas, hepatocyte lesions, liver vascular lesions) were found in all treatment and control sets. There was no indication that a specific anesthetic or anesthetic dose was carcinogenic. Our results do not confirm the suggestion that isoflurane is a hepatocarcinogen, nor do our data suggest that the modern inhaled anesthetics pose a significant threat of carcinogenicity.

Anesthesia, Inhalation↗