Biomedical subjects

D M Duhl

Publications and source records attributed to D M Duhl.

22 records · Page 2Linked to original sources

PubMed1983

Rapid method for preparation of nuclei from a mucin-producing solid tumor.

Nuclei were prepared from the human colon mucin-producing tumor GW-39. The method described involves incubation in beta-mercaptoethanol under mild conditions and results in the preparation of nuclei free of the mucin web that initially enmeshes them. A sensitive colorimetric immunoassay was used to confirm that nuclei prepared in this fashion were generally free of contaminating mucin. This method is mild, rapid, and should be applicable to other mucin-producing tumors.

Cell Fractionation↗

PubMed1982

Tumor-associated chromatin antigens of human colon adenocarcinoma cell lines HT-29 and LoVo.

Antiserum to dehistonized chromatin from human colon adenocarcinoma cell line HT-29 was raised in rabbits and used for the immunodetection of colon tumor-associated nuclear antigens. Quantitative microcomplement-fixation studies indicated that the antiserum had reactivity similar to those of chromatins of two human colon adenocarcinoma cell lines (HT-29 and LoVo) and with nonneoplastic colon. Immunocytochemical localization showed the chromatin antigens to be evenly dispersed throughout the nucleus. Immunochemical staining of electrophoretically separated chromosomal proteins transferred to nitrocellulose sheets revealed several intensely staining antigens predominantly in the molecular weight range of 62,000 to 75,000. When the antiserum was immunoabsorbed with nonneoplastic human colon chromatin, two antigens with molecular weights of 67,000 and 92,000 were identified only with the tumor chromatins. Antiserum immunoabsorbed with either LoVo or HT-29 chromatin failed to show any immunoreactivity, suggesting that these tumor-associated proteins, or antigenic sites residing on these proteins, are identical in both colon tumor cell lines.

Adenocarcinoma↗

PubMed1982

A nuclear matrix antigen HeLa and other human malignant cells.

Antisera were obtained in rabbits to preparations of dehistonized chromatin from HeLa cells. By complement fixation assays, the antisera reacted with HeLa cell chromatin but only marginally with human placenta chromatin. The complement-fixing reactivity of the antisera was inversely related to the amount of dehistonized chromatin used for immunization. Immunochemical staining of electrophoretically separated chromosomal proteins transferred to nitrocellulose sheets revealed numerous antigens in chromatin preparations from several human tumors, placenta, and normal kidney. While immunoabsorption of the antisera with placenta chromatin removed some of the immunochemical staining, many of the electrophoretically separated antigens resisted repeated immunoabsorptions. However, further comparisons revealed that only one major protein antigen (band at an approximate molecular weight of 81,000) was represented in all the assayed human tumors while being absent from human placenta or kidney. Fractionation of HeLa cells into three cytoplasmic and several nuclear fractions showed that almost all the antigens recognized by antisera to dehistonized chromatin were nuclear. The antigenic protein with an approximately molecular weight of 81,000 was found associated with the nuclear matrix fraction.

Antigens↗

PubMed1979

Regulation of mammalian protein synthesis in vivo. Simulated transport of nuclear ribonucleoprotein complexes to the cytoplasm after cycloheximide treatment.

By studies in vivo with purified nuclei from rat liver, it was shown that a non-lethal dose of cycloheximide causes a decrease in the content of total nuclear ribonucleoprotein complexes by 2h after treatment. Analysis of the complex by sucrose-density-gradient centrifugation substantiated this observation for the faster-sedimenting complex, but showed an increase in the content of a smaller complex. Radioisotope incorporation studies showed that the overall decrease in nuclear ribonucleoprotein content was not due to a decreased synthesis, but rather to an increased transport to the cytoplasm. The results of a double-radioisotope technique support the conclusion that, during the inhibitory phase of protein synthesis brough on by cycloheximdie, gene transcription continues and the gene product is transported to the cytoplasm for subsequent translation.

Animals↗