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At least 253 records · Page 14Linked to original sources
PubMed1982

Time- and concentration-dependent inhibition of the clonogenic growth of N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide-induced murine bladder tumor cell lines by cis-diamminedichloroplatinum(II).

The influence of the concentration and time of exposure to cis-diamminedichloroplatinum on the inhibition of the clonogenic growth of three N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide mouse bladder tumor cell lines was evaluated in a tumor colony assay. Drug testing was performed in the murine model, and tumor cells were removed from the animals for in vitro testing. Murine drug testing revealed marked cis-diamminedichloroplatinum sensitivity of all three mouse bladder tumor lines. One-hr incubation in cis-diamminedichloroplatinum was an adequate time of drug exposure to produce in vitro colony survival curves predictive of in vivo sensitivity to the drug. Furthermore, it was found that 6- to greater than 24-hr exposure to the drug was required to produce colony survival curves in the tumor colony assay predictive of tumor sensitivity. High drug concentrations using 1-hr drug incubation or continuous incubation in drug both produced colony survival curves predictive of tumor sensitivity. Both methods, however, would require higher products of the drug concentration multiplied by time curves than could theoretically be clinically achievable in the murine model. Until pharmacokinetic data on cis-diamminedichloroplatinum are available in this murine model, higher drug sensitivity boundaries than are presently being used for other chemotherapeutic agents will have to be utilized when testing these mouse bladder tumor cell lines for their sensitivity to cis-diamminedichloroplatinum in a tumor colony assay.

Animals↗
PubMed1981

The effect of single dose N-methyl-N-nitrosourea on bladder carcinogenesis by N-[4-(5-nitro-2-furyl)-2-thiazolyl] formamide in rats.

The effect of a single intravesical dose of N-Methyl-N-Nitrosourea (MNU) on bladder carcinogenesis in Fischer rats by a suprathreshold dose of N-[4-(5-nitro-2-furyl)-2-thiazolyl] formamide (FANFT) was studied. Animals were sacrificed periodically during the course of the study and the experiment was terminated 50 weeks. Carcinomas were first noted in the MNU + FANFT group at 35 weeks versus 37 weeks for the group receiving FANFT alone. At 50 weeks, carcinomas were seen in 40 of 49 animals in the MNU + FANFT group and in 40 of 48 animals in the FANFT group. Of the animals developing bladder carcinomas 50 per cent receiving MNU + FANFT and 32 per cent receiving FANFT had high grade tumors. Six per cent of the animals receiving MNU alone developed bladder carcinomas whereas none was seen in a control group. In this system, the addition of an inducing dose of MNU did not alter the induction rate or results of carcinogenesis by FANFT. There was a tendency for higher grade tumors in those animals receiving the inducing dose of MNU.

Animals↗
PubMed1981

Effect of L-tryptophan and sodium saccharin on urinary tract carcinogenesis initiated by N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide.

The effect of sodium saccharin (SAC) or L-tryptophan (LT) on urinary bladder carcinogenesis initiated by feeding N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) for 4 weeks as 0.2% of the diet to male F344 weanling rats was evaluated. SAC was fed as 5% of the diet, and LT was 2% of the diet. FANFT fed for 4 weeks followed by 100 weeks of control diet did not produce any carcinomas; one of 25 rats developed a bladder papilloma. Of 26 rats fed SAC for 100 weeks after FANFT, two developed papillomas, and five developed carcinomas (p less than 0.03). Of 26 rats fed LT for 100 weeks after FANFT, three developed papillomas, and two developed carcinomas (p greater than 0.1) Eight rats fed FANFT for 72 weeks all developed bladder carcinomas, but rats fed control diet alone, control diet with SAC, or control diet with LT did not develop any bladder tumors. Scanning electron microscopic examination of Week 104 of the experiment showed the presence of pleomorphic microvilli on the bladder surface of some rats fed SAC of LT whether following 4 weeks of control diet alone or 4 weeks of FANFT. Four weeks of FANFT feeding, a lower dose than used previously in our studies, appears to be a subcarcinogenic level. Under these experimental conditions, the promoting activity of SAC is demonstrated with statistical significance. The results with LT were not statistically significant.

Animals↗
PubMed1980

Morphological effects of mitomycin C administered intravesically to normal mice and mice with N-[4-(5-nitro-2-furyl)-2-thiazolyl]-formamide-induce bladder neoplasms.

The intravesical administration of mitomycin C to normal and N-[4-(5-nitro-2-furyl)-2-thiozolyl]formamide-induced bladder tumor-carrying mice at initial concentrations of 2 and 5 mg/ml for 2 hr resulted in marked morphological effects including cytoplasmic and nuclear abnormalities and disruption of surface architecture. Tumors cells and normal urothelial cells were sensitive to the effects of mitomycin C. These effects were limited to epithelial cells.

Animals↗
PubMed1977

A long-term study of reversible and progressive urinary bladder cancer lesions in rats fed N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide.

Hyperplasia and, ultimately, neoplasia of bladder epithelium were produced by feeding 0.2% N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide (FANFT) to weaning male Fischer rats. Hyperplasia induced by FANFT feeding for 2, 4, or 6 weeks, followed by feeding control diet until the end of the 84-week experiment, was reversible, and at the end of the experiment bladder epithelium in these animals was normal by light and scanning electron microscopy. Hyperplasia produced by 8 or more weeks of FANFT feeding was irreversible and by 84 weeks had resulted in bladder tumors in all animals fed FANFT for 12 or more weeks and in 4 of 5 and 6 of 7 animals fed FANFT for 8 and 10 weeks, respectively. The epithelial changes after 6 and 8 weeks of FANFT were similar by light microscopy but different by scanning electron microscopy. Pleomorphic microvilli seen with scanning electron microscopy are the hallmark of irreversible, and possibly progressive, epithelial proliferative change.

Animals↗
PubMed1977

Uridine 5'-diphosphate galactose: glycoprotein galactosyl transferase activity in exfoliated bladder epithelial cells in rats fed N-(4-(5-nitro-2-furyl)-2-thiazolyl) formamide.

Urine samples of normal male Fischer rats or rats fed 0.2% N-[4-(5-nitro-2-furyl)-2-thiazolyl]formamide for 6,8 or 30 weeks were collected and centrifuged 50 weeks after beginning treatment. After being sonicated and assayed (with purified desialylated ovine submaxillary mucin as acceptor glycoprotein), the exfoliated bladder cells obtained from the urines of treated rats showed uridine 5'-diphosphate galactose:glycoprotein transferase activity. The specific enzymatic activity of the enzyme from cells of 30-week-treated rats was about 10 times higher than from normal rats. The enzyme from cells of hyperplastic rats (treated 6 or 8 weeks) was only slightly higher in specific activity than that of normal rats. A similar was obtained at a later stage of bladder tumor induction, when the urines from 30-week-treated rats contained blood. A correction was made for protein contributed by the blood clot. The possibility that the blood clot contributed galactosyl transferase activity was excluded. Activity of the enzyme was detected in normal rat bladder tissue and in normal human urine.

Animals↗