In N-methyl-N-nitrosourea (MNU)-induced colon cancer modeling in rats, it was aimed to evaluate the regressive effect of grayanotoxin-rich Turkish mad honey and 5-fluorouracil (5-FU), separately together. Study groups were control group (CG), (CCG), 5-Flourouracil (FUG), (HG), 5-FU combined (FU-HG). WBC, lymphocyte, eosinophil, basophil, serum LDH, TOS, total protein values determined rats CCG ...

Contrary to rats of the highly sensitive inbred strain BDIX, BDIV rats are resistant to the induction of malignant schwannomas by N-ethyl-N-nitrosourea, arising predominantly in the trigeminal nerves. A point mutation of the neu/erbB-2 gene diagnostic of N-ethyl-N-nitrosourea-induced rat schwannomas is an early marker of Schwann precursor cells at high risk of subsequent malignant transformatio...

The long-patch mismatch repair pathway contributes to the cytotoxic effect of methylating agents and loss of this pathway confers tolerance to DNA methylation damage. Two methylation-tolerant mouse cell lines were identified and were shown to be defective in the MSH2 protein by in vitro mismatch repair assay. A normal copy of the human MSH2 gene, introduced by transfer of human chromosome 2, re...

The antitumor activities of seventeen antitumor alkylating agents have been studied in the xenograft of human mammary carcinoma transplanted in nude mice (MX-I). The drugs employed in this study were; cyclophosphamide. ifosfamide. 1-(2-chloroethyl)-3-cyclohexyl-l-nitrosourea (CCN U). 1-(2-ehloroethyl)3-(4-methylcyclohexyl)-I-nitrosourea (me-CCN U). 2-[3-(2-ehloroethyl)-3-nitrosoureido]-2-deoxyD...

A Walker 256 rat carcinoma cell line (WR) with acquired resistance to nitrogen mustards has been found to lack crossresistance to nitrosoureas. Although total cellular glutathione pools were similar in the parent (WS) and resistant cell lines (WS, 2.5 x 10~6; WR, 2.0 x 10~6 mol/mg protein), glutathione reductase activity was 3.98 in WR compared to 8.67 nmol reduced nicotinamide adenine dinucleo...

BACKGROUND Currently, there are no known effective treatments for recurrent glioblastoma once patients have progressed on a bevacizumab-containing regimen. We examined the efficacy of adding nitrosoureas to bevacizumab in patients who progressed while on an initial bevacizumab-containing regimen. METHODS In this retrospective study, we identified adult patients with histologically confirmed g...

Mitogen-stimulated human lymphocytes have an increased capacity to repair many forms of DNA damage caused by IV, ionizing radiation, and chemical carcinogens. Human lymphocytes rely on a particular DNA repair protein, O'-alkylguanine-DNA alkyltransferase (alkyltransferase) to repair efficiently O6-alkylguanine, an important mutagenic adduct formed by nitrosoureas and other /V-nitroso compounds....

Myelosuppression is the dose-limiting toxicity for nitrosourea chemotherapy. This toxicity predominantly involves modification of the O6 position of guanine with an alkyl moiety. The enzyme responsible for repair of O6-alkylguanine adducts, O6-alkylguanine-DNA alkyltransferase (alkyltransferase), is expressed at low levels in bone marrow (BM) cells. High alkyltransferase expression prevents the...

A shuttle vector plasmiti. pYZ289, was constructed from the pZ189 plasmid and polyoma virus DNA. The plasmid contains a supF gene as a marker of mutation and can replicate in both Escherìchiacoli and mouse cells. The pYZ289 plasmids treated with /V-methyl-A'-nitrosourea were passed through mouse cells originating from skin tumors, which are either proficient (III IS) or deficient (III 8) in O'...