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Biomedical subjects

S N Mueller

Publications and source records attributed to S N Mueller.

24 records · Page 2Linked to original sources
PubMed1981

Proliferative characteristics of clonal endothelial cell strains.

We have utilized clonal strains of bovine fetal aortic endothelial cells to study cellular senescence in a differentiated cell type of physiological significance. Serial subcultivation of nine endothelial clones derived from three fetal calf aortas revealed proliferative life-spans in vitro of 53--125 population doublings (PDs), compared with 60 and 143 PDs for two lines of bovine fetal lung cells and 85 and 147 PDs for two lines of bovine vascular smooth muscle cells. Serial growth curves showed marked reductions associated with endothelial cellular senescence both in cellular growth rate and culture plateau density. Studies of the 24-hour [3H]-thymidine labeling index versus percentage of proliferative life-span completed indicated that clonal endothelial cultures contained a large proportion (greater than 90%) of rapidly cycling cells until about 75% of the lifespans were completed. Senescent endothelial cells showed evidence of large increases in cell area, cell volume, and protein content. In those clones examined, one specialized endothelial function, Factor VIII antigen expression, was retained qualitatively throughout the life-spans.

Animals↗
PubMed1980

Cellular senescence in a cloned strain of bovine fetal aortic endothelial cells.

The life-span in vitro and other proliferative characteristics of a strain of endothelial cells cloned from the aorta of a fetal calf were examined. Cultures of these cells had a replicative life-span of approximately 80 cumulative population doublings. Growth rates in the logarithmic phase and plateau densities decreased as the cumulative population-doubling level increased. After approximately 65 percent of the life-span of a culture was completed, the percentage of cells that incorporated [3H]thymidine during a 24-hour labeling period began to decrease rapidly. The cells expressed factor VIII antigen and their intercellular borders were stainable with silver nitrate throughout the life-span of each culture. Average cellular attachment size increased more than threefold between cumulative population-doubling levels 41 and 80. The facility with which cloned strains of endothelial cells can be isolated should encourage further exploitation of this important cell culture model.

Animals↗
PubMed1980

Benzo(a)pyrene metabolism in bovine aortic endothelial and bovine lung fibroblast-like cell cultures.

The metabolism of [3H]benzo(a)pyrene ([3H]BP) in bovine aortic endothelial and bovine lung fibroblast-like cells in vitro was investigated. Both cell types metabolized BP to organic solvent-extractable and water-soluble metabolites. The major organic solvent-extractable metabolites were 9-hydroxy-benzo(a)pyrene and 3-hydroxybenzo(a)pyrene; 7,8-dihydro-7,8-dihydroxybenzo(a)pyrene, 9,10-dihydro-9,10-dihydroxy-benzo(a)pyrene, and BP quinones were also formed. No glucuronide or sulfate conjugates of BP metabolites were detected. When exposed to [3H]-3-hydroxybenzo(a)pyrene, both cell types metabolized this phenol to water-soluble derivatives, probably through oxidation rather than conjugation of the molecule. These results demonstrate that endothelial cells metabolze BP to a proximate carcinogenic derivative, the 7,8-dihydrodiaol. Thus, efforts to predict the biological effects of hydrocarbons of an organism must take into account possible metabolic activation by endothelial cells as well as by other target tissues. The formation of unconjugated, phenolic hydrocarbon derivatives by bovine cells suggests their use as a model system for studying the contribution of phenols to the induction of biological effects by hydrocarbons.

Animals↗
PubMed1975

Free and membrane-bound ribosomes in normal and methylcholanthrene-treated mouse epidermis.

Total and free ribosomes were isolated from postnuclear supernatants of trypsinized normal and 3-methylcholanthrene-treated epidermis from female CD-1 mice. Membrane-bound ribosomes were determined as the calculated difference between total and free ribosomes. The value for total ribosomes from normal epidermis in the resting phase of the hair growth cycle was 0.32 mg. of ribosomal RNA per gm. of epidermis, or 0.07 mg. of ribosomal RNA per mg. of homogenate DNA. About 96 per cent of the ribosomes were free and 4 per cent were membrane-bound. Five days after a single application of 2 mu moles of 3-methylcholanthrene to the dorsal skin in the resting phase of the hair growth cycle, there was epidermal hyperplasia and cellular hypertrophy. Total ribosomes increased 2- to 3-fold, to 0.80 mg. of ribosomal RNA per gm. of epidermis, or 0.21 mg. of ribosomal RNA per mg. of homogenate DNA. This increase was further characterized as proportionate increases of both free and membrane-bound ribosomes.

Animals↗