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Biomedical subjects

S R PELC

Publications and source records attributed to S R PELC.

At least 19 recordsLinked to original sources
PubMed1964

LABELLING OF DNA AND CELL DIVISION IN SO CALLED NON-DIVIDING TISSUES.

Autoradiographs of adult mice killed at various times after injection of tritiated thymidine show significant numbers of labelled nuclei in organs in which mitoses are either very rare or completely absent. The proportion of labelled cells that divide was estimated from the decline in the number of grains per nucleus, the number of pairs of labelled cells in sheets of epithelium in squashes, the number of labelled metaphases after 6 hours' treatment with Colcemid, and the ratio of mitotic index to labelling index. The longest possible duration of G(2) in the epithelial cells of seminal vesicles was deduced from the results of Feulgen photometry. The results show that only a small proportion of the labelled cells divide in the seminal vesicles and liver, whilst probably none divide in brain, smooth muscle, and heart muscle. It is suggested that, in the so called "non-dividing tissues" of adult mice, cells periodically renew their DNA by a process the details of which are as yet unknown.

Animals↗
PubMed1960

Incorporation and rate of loss of S35-methionine by adult rat trachea in organ cultures and in living animals.

Full-thickness pieces of adult rat trachea were supported on rayon on the surface of clotted medium in watch glasses. Differentiated epithelium was reduced in height during 25 days of cultivation because basal cells and some columnar cells migrated to cover exposed parts of the explants and because some differentiated cells died and were shed. S(35)-methionine was (a) placed on explants in vitro and (b) injected intraperitoneally in living rats. Cultured tissues and tissues of living rats were examined by autoradiography at 4 and 24 hours and 4, 7, and 11 days after labeling. Although migratory undifferentiated epithelial cells appeared in cultured trachea, all living epithelial cells in vitro incorporated and subsequently lost S(35)-methionine to the same extent as did epithelium of intact rats. The biologic half-life of methionine in rat tracheal epithelium in vivo and in vitro was about 5 days.

Animals↗