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Biomedical subjects

E Robbins

Publications and source records attributed to E Robbins.

85 records · Page 5Linked to original sources
PubMed1967

The role of calcium in the regulation of the steady-state levels of sodium and potassium in the HeLa cell.

Studies on HeLa cells in spinner culture at pH 7.0 and 37 degrees have shown that [Na](i) decreased and [K](i) increased with increasing [Ca](o). In Na-free (choline) medium [K](i) remained high whether or not Ca was present in the medium. [Na](i) and [K](i) approached a new steady state within 1 min after transfer to Ca-free medium and returned to the initial values within 15 min upon readdition of Ca. 40% of the cell Ca exchanged within 1 min followed by a slow exchange of the remaining Ca over several hours. [Ca](i) increased with decreasing [Na](o) but was independent of [K](o). Equimolar Mg did not substitute for Ca in maintaining low [Na](i) and high [K](i). Under steady-state conditions about 50% of the cell Na exchanged in accordance with a single rate constant. The initial Na influx was 270, 100, and 2.5 microM/liter of cell water/sec for 0, 0.10, and 1.0 mM [Ca](o), respectively. When Na transport was inhibited with strophanthidin and [Na](i) and [K](i) allowed to reach a steady state, Na influx was more rapid for cells incubated in Ca-free medium than for cells incubated in medium containing 1.0 mM Ca. These results suggest that Ca competes with Na at the cell membrane and thus controls the passive diffusion of Na into the cell.

Biological Transport↗
PubMed1966

Polyribosome disaggregation during metaphase.

Polyribosomes as examined by both sucrose-gradient analysis and electron microscopy disaggregate during metaphase in both normal HeLa cells and those arrested in metaphase by treatment with colchicine.

Carbon Isotopes↗
PubMedDate not supplied

Thrombogenicity of Teflon versus copolymer-coated guidewires: evaluation with scanning electron microscopy.

Utilizing the scanning electron microscope, we compared a new guidewire with copolymer coating with standard Teflon-coated, coiled-spring guidewires in both clinical and in vitro settings. Intense thrombogenicity was observed with the Teflon-coated guidewires with formed thrombi ranging in size from 50-100 microns. No formed thrombus was noted on any of the specimens of the copolymer guidewire, although isolated clumps of platelets and erythrocytes without fibrin strands were seen infrequently. We conclude that the copolymer guidewire is markedly less thrombogenic than Teflon-coated guidewires.

Cerebral Angiography↗