RESUMEN
A subline of Ehrlich ascites carcinoma (EAC) cells resistant to 5-fluoro-2'-deoxy-uridine (FdUrd) was developed by continuous exposure to progressively increasing concentrations of the drug (35-75 mg/kg per day) during 15 passages through mice. Since then, the EAC cells have been retransplanted more than 80 times through drug-untreated mice and continue to be resistant. After adaptation to growth in suspension culture the drug-adapted cells were 1000 times more resistant to FdUrd in comparison with parental ones, and remained near-tetraploid with doubling time longer than in parental line. The activity of thymidine kinase was deeply depressed (100-fold) whereas that of thymidylate synthetase several-fold increased in the resistant EAC cells, both grown in vivo and in vitro.
Asunto(s)
Carcinoma de Ehrlich/tratamiento farmacológico , Floxuridina/farmacología , Animales , Línea Celular , Resistencia a Medicamentos , Femenino , Humanos , Neoplasias Hepáticas Experimentales/metabolismo , Ratones , Trasplante de Neoplasias , Timidina Quinasa/metabolismoAsunto(s)
Fenómenos Fisiológicos Nutricionales Infantiles , Dieta , Minerales/administración & dosificación , Servicios de Salud Escolar , Adolescente , Calcio/administración & dosificación , Niño , Humanos , Hierro/administración & dosificación , Magnesio/administración & dosificación , Valor Nutritivo , Fósforo/administración & dosificación , Polonia , Potasio/administración & dosificaciónRESUMEN
1. Mouse fibroblast L-cells susceptible to methoprene and to a synthetic C18 juvenile hormone were cultivated for several months in the medium with one of these compounds at a subeffective concentration (10 microgram/ml) then allowed to grow in the medium with the particular compound at an effective concentration (20 microgram/ml). 2. This resulted in establishing the cells whose mitotic activity, morphology, pattern of growth and the rate of macromolecular biosynthesis (even after cultivation for several months in the presence of methoprene or the hormone at originally effective concentration) did not differ from those for control cells.