ABSTRACT
En resumen, parece ser que el proceso necesario, al menos conceptualmente que le permita a uno construir una noción adecuada del mecanismo involucrado durante la carcinogénesis inducida por etionina, puede ser relevante a un proceso más general y fundamental aplicable a todos los carcinógenos. Se ha descrito un intento que trata de aportar un mecanismo considerado en este artículo, también enfatiza la importancia de la activación de proteínas embriónicas como un ejemplo de un proceso más general que se requiere para la carcinogénesis
Subject(s)
Rats , Animals , alpha-Fetoproteins/genetics , Ethionine/toxicity , Liver Neoplasms, Experimental/chemically induced , Liver Neoplasms/chemically induced , Gene Expression Regulation, Neoplastic , Cell Differentiation , DNA/drug effects , Heterochromatin/metabolism , Methylation , Liver Neoplasms, Experimental/genetics , Liver Neoplasms/geneticsABSTRACT
Distamycin-A, an oligopeptide antibiotic with a N-methylpyrrole ring system and propionamide side chain, preferentially forms stable bonds with AT rich double stranded DNA. When introduced to cell cultures, it inhibits condensation of the heterochromatic region of the Y chromosome. The frequency of metaphases showing inhibition of heterochromatin condensation of the Y chromosome was found to be dependent on the treatment time and concentration of distamycin-A in the culture medium. When distamycin-A was added to a concentration of 100 micrograms/ml at the start of the culture (72 hours), the frequency of Y heterochromatin decondensation was found to be 48%, 30% and 6% in amniotic fluid, lymphocyte and fibroblast cultures respectively. The highest frequency of metaphases with decondensed Y heterochromatin were observed when distamycin-A treatment was carried out for the last 24 hours prior to harvest, the frequencies being 94%, 72% and 59% in amniotic fluid, lymphocyte and fibroblast cultures respectively. Increase in the concentration of distamycin-A from 25 micrograms/ml to 50 micrograms/ml during the last 24 hours of culture increased the incidence of metaphases with Y heterochromatin decondensation from 51% to 69% in amniotic fluid, 40 to 49% in lymphocyte and 29% to 31% in fibroblast cultures. Highest frequency of metaphases with Y heterochromatin decondensation were observed when the cultures were exposed to distamycin-A at a concentration of 100 micrograms/ml for the last 24 hours of culture.