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Biomedical subjects

C A Sprague

Publications and source records attributed to C A Sprague.

13 recordsLinked to original sources
PubMed1974

Dominance of the senescent phenotype in heterokaryons between replicative and post-replicative human fibroblast-like cells.

In heterokaryons between senescent and young diploid fibroblast-like cells, dominance of the former with respect to nuclear DNA synthesis (incorporation of [(3)H]thymidine) was demonstrated. For identification of the respective partners, double-layer autoradiography was used after the old cells were labeled with [(3)H]methionine and the young cells were labeled with [(14)C]thymidine. Synchrony of nuclear labeling (i.e., all nuclei in a cell labeled with [(3)H]thymidine) was observed in the majority of di- and polykaryons during the second and third of three 24-hr periods of labeling with [(3)H]thymidine. The results are compatible with either terminal differentiation or error theories of clonal senescence.

Adolescent↗
PubMed1974

Clonal selection, attenuation and differentiation in an in vitro model of hyperplasia.

Observations of the growth kinetics and morphologies of clones and subclones of diploid human skin fibroblast cultures lead to the working hypothesis that these cells, presumably like their counterparts in healing wounds, constitute a differentiating system. There is attenuation of the growth of serial clones, with continual selection for more vigorous stem cells. The latter segregate daughter cells of varying growth potential, including a class of cells which may be regarded as terminally differentiating; we propose that such cells may be histiocytes or macrophages. These studies a) demonstrate extensive epigenetic heterogeneity in fibroblast cultures, b) suggest that hyperplastic foci may be monoclonal or oligoclonal, c) rule out a simple biologic clock mechanism as an explanation of clonal senescence, d) suggest a new approach to the analysis of various inborn errors of metabolism, such as Werner's Syndrome.

Cell Differentiation↗
PubMed1969

Parasexual cycle in cultivated human somatic cells.

Somatic segregation for three different autosomes was demonstrated in two strains of human diploid fibroblasts derived from subjects known to be heterozygous for chromosomal variants. Recombinant diploid cells appeared within cultures of tetraploid clones isolted from mass cultures. Tetraploid cells regularly occur in mass cultures and within clones of diploid cells. Such a parasexual cycle (2n-->4n-->2n), with recombination of entire linkage groups, could from the basis of a beginning formal genetic analysis in man.

Biopsy↗