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Biomedical subjects

S T Crooke

Publications and source records attributed to S T Crooke.

At least 19 recordsLinked to original sources
PubMed1979

Deoxyribonucleic acid binding studies on several new anthracycline antitumor antibiotics. Sequence preference and structure--activity relationships of marcellomycin and its analogues as compared to adriamycin.

The deoxyribonucleic acid (DNA) binding characteristics of adriamycin and several new anthracycline glycosides, including marcellomycin, aclacinomycin, rudolfomycin, musettamycin, and pyrromycin, have been studied. The fluorescence spectra were determined for all six anthracyclines, and the fluorescence quenching effects caused by interactions with the natural DNAs poly(dAdT)--poly(dAdT) and poly(dGdC) were characterized. Binding parameters were determined by Scatchard analyses of results obtained by spectrofluorometric titrations of anthracyclines with DNA. Consistent with earlier structure--activity relationship studies of nucleic acid synthesis inhibitory effects, the results demonstrate a correlation between the length of the glycosidic side chain and DNA binding affinity. In addition, the sugar residue 2-deoxyfucose appears to confer greater DNA binding ability than do the sugars rednosamine and cinerulose when present in the terminal position of the glycosidic side chain, also in agreement with earlier studies. The sequence preference of anthracycline--DNA interaction has been examined by using DNAs of varying GC content, including the naturally occurring calf thymus DNA (43% GC), Clostridium perfringens DNA (28% GC), and Micrococcus luteus DNA (72% GC) and the synthetic double-stranded copolymers poly(dGdC)--poly(dGdC) and poly(dAdT)--POLY(DAdT). The results demonstrate that although adriamycin shows an absolute requirement for GC sequences for DNA binding, marcellomycin and its analogues showed no such sequence requirement. Furthermore, an AT preference for DNA binding was demonstrated with marcellomycin and its analogues.

Aclarubicin↗
PubMed1979

Cisplatin, bleomycin, and vinblastine combination therapy of testicular tumors: an analysis.

A combination regimen consisting of cisplatin, bleomycin, and vinblastine was evaluated in 86 patients with metastatic testicular tumors. Prior therapy included surgical resection of primary tumor (84 patients), radiotheapy (21 patients), chemotherapy (33 patients). Thirteen patients received prior bleomycin and vincristine or vinblastine. Of 80 evaluable patients 51 achieved complete response (CR) and 26 achieved partial response (PR), for an overall response rate 96.5%. There was no significant difference in response rates or survival with respect to prior therapy, sites of metastatic lesions, and tumor histology. The median survival time was not reached in an observation period of 44+ months. Sixty patients were alive 11+--44+ months, and 57 of these were free of disease. Thirty-two of the 60 patients (53%) had a survival time greater than 20 months. Toxicities included nephrotoxicity (18 patients) leukopenia, (69 patients), thrombocytopenia (nine patients), and anemia (56 patients). Bleomycin-induced pulmonary toxicity was fatal in one patient. Other toxicities included nausea and vomiting, stomatitis, fever, alopecia, and neurological effects.

Adolescent↗
PubMed1979

Use of covalently closed circular deoxyribonucleic acid for prescreening for antitumor compounds.

The interactions of PM-2 deoxyribonucleic acid (DNA) with 20 known antineoplastic agents were studied using agarose gel electrophoresis and fluorescence assay systems. Actinomycin D and adriamycin (and all other anthracyclines studied) induced superhelical conformational changes in PM-2 DNA. Bleomycin A2, tallysomycin, neocarzinostatin, macromomycin, and hedamycin degraded PM-2 DNA under various conditions. The potential utility of PM-2 DNA as an antitumor antibiotic prescreening tool was further studied by examining the effects of 200 broths on PM-2 DNA employing both fluorescence and agarose gel electrophorectic assays. The assays were shown to be sensitive and rapid and to provide information not provided by other prescreens with which the PM-2 DNA assays were compared.

Antineoplastic Agents↗
PubMed1979

Purification and mechanism of action of macromomycin.

Macromomycin (MCR), a polypeptide antibiotic previously shown to have antitumor activity in experimental tumors, has been purified into an electrophoretically homogeneous component with an approximate molecular weight of 12,500. MCR has alanine as an NH2-terminal amino acid, 4 cysteine residues, and no arginine or methionine residues. With a fluorescence assay and agarose gel electrophoresis, MCR was shown to induce strand breaks in PM2 DNA in vitro. 2-Mercaptoethanol inhibited the DNA cleavage activity of MCR. When incubated with Novikoff hepatoma ascites cells in tissue culture, MCR caused Novikoff hepatoma ascites cell DNA degradation as observed by the slower sedimentation of DNA on alkaline sucrose density gradient centrifugation when compared to untreated cell DNA. DNA synthesis in Novikoff hepatoma ascites cells was inhibited by 80% after a two-hr treatment with MCR (0.03 microgram/ml). RNA and protein syntheses were inhibited by 25 and less than 10%, respectively, at this concentration of drug. At a concentration of MCR (1.0 microgram/ml), syntheses of DNA and RNA in Novikoff hepatoma ascites cells were totally inhibited. The results of this study suggest that MCR may inhibit tumor cell growth by causing DNA breakage with subsequent inhibition of DNA and other macromolecule syntheses.

Animals↗
PubMed1979

Acute ultrastructural effects of the antitumor antibiotic carminomycin on nucleoli of rat tissues.

Male Sprague-Dawley rats were treated with carminomycin i.v. in doses ranging from 1 to 40 mg/kg. Within 1 hr after the administration of carminomycin, 20 mg/kg, nucleoli of cardiac and skeletal muscle cells were segregated, while nucleoli of liver parenchyma cells were unaffected. Three and one-half hr after drug administration, cardiac muscle nucleoli reverted to normal ultrastructure. However, some skeletal muscle cell nucleoli were still segregated. Following treatment with carminomycin, 10 mg/kg, no significant ultrastructural changes were observed. These results demonstrate that at sufficiently high doses carminomycin induces ultrastructural lesions in nucleoli of both cardiac and muscle cells. The dose of carminomycin required to produce nucleolar segregation in cardiac and skeletal muscle is 6 times greater than the dose of Adriamycin (3.5 mg/kg) required to induce equivalent alterations.

Animals↗