Correlation of human bladder tumor recurrence with changes in clonogenicity of urothelial cells.

Over a 2-year period 340 cystoscopies were performed on 174 patients (126 men and 48 women) followed up for previously treated transitional cell tumor of the bladder or new cases suspected of having bladder tumor. Bladder washings taken at cystoscopy in 66% yielded cells for clonogenic assay. Patients with transitional cell tumors had an average clonogenic index (CI) of 14 (+/- 5) colonies per 10(5) viable urothelial cells, whereas previously tumorous patients with tumor-free bladders had an average CI of 6 +/- 1 colonies (P less than 0.

Mutagenic activation of dialkylnitrosamines by intact urothelial cells.

Intact urothelial cells isolated from bladders of untreated inbred NZO/BIGd or NZC/BIGd mice and NZR/Gd rats activated dimethyl, diethyl, dipropyl, and dibutyl nitrosamines in a liquid culture mutagenesis fluctuation assay using Salmonella typhimurium TA100 as target organism. Rat and mouse urothelial cells were highly effective at 1.5 X 10(5) cells/ml, in O2 gas phase, and no cofactors were required.

Enhancement of rat ACT-1 tumor clonogenicity by xenogeneic mouse macrophages.

In vitro growth of rat atriocaval epithelial tumor cells (ACT-1) was enhanced by the inclusion of xenogeneic mouse adherent peritoneal exudate cells (PECs) in a two-layer soft agar system. A linear relationship was found between the number of cells plated and the number of colonies when ACT-1 tumor cells were plated at plating densities of between 1 and 5 X 10(5) cell/60 mm plate (r = 0.9, P less than 0.

Unusually high susceptibility of NZR/Gd rats to bladder cancer induction by low doses of nitrosomethylurea.

Inbred female rats of the NZR/Gd strain were exceptionally susceptible to nitrosomethylurea (NMU) toxicity after intravesical instillations. After only 1.0 mg NMU total given in 10 fractions, 100% of NZR rats developed malignant bladder tumours.