scholarly journals The effect of oxygen and vitamin E on the lifespan of human diploid cells in vitro.

1977 ◽  
Vol 74 (1) ◽  
pp. 58-67 ◽  
Author(s):  
A K Balin ◽  
D B Goodman ◽  
H Rasmussen ◽  
V J Cristofalo
Keyword(s):  
Oxygen Toxicity ◽  
Alpha Tocopherol ◽  
Ambient Oxygen ◽  
Oxygen Tensions ◽  
Effect Of Oxygen ◽  
Population Doublings ◽  
Human Diploid Cells ◽  
Diploid Cells ◽  
Phase Out

Human diploid cells (WI-38) were serially subcultivated at partial pressures of oxygen (Po2) ranging from 5.6 mm Hg to 608 mm Hg. At a Po2 of 5.6 mm Hg, the number of doublings to phase out was less than that of control cells at a Po2 of 137 mm Hg. Cultures grown at Po2's of 24, 49, or 137 mm Hg grew at the same rate and phased out after a similar number of population doublings. Population lifespan was markedly shortened by chronic exposure to elevated Po2's, a phenomenon that was, in part, reversible. d-1-alpha-Tocopherol (10 microgram/ml or 100 microgram/ml) homogenized into the medium at each weekly subcultivation did not extend the lifespan of cells at reduced, ambient, or elevated oxygen tensions. These results indicate that neither oxygen toxicity nor free radical reactions play a significant role in limiting the lifespan of WI-38 cells grown in vitro under ambient oxygen tensions (Po2 137 mm Hg).

scholarly journals Oxygen-sensitive stages of the cell cycle of human diploid cells.

1978 ◽  
Vol 78 (2) ◽  
pp. 390-400 ◽  
Author(s):  
A K Balin ◽  
D B Goodman ◽  
H Rasmussen ◽  
V J Cristofalo
Keyword(s):  
Cell Cycle ◽  
Dna Synthesis ◽  
Oxygen Tension ◽  
Cycle Growth ◽  
Partial Pressures ◽  
Oxygen Sensitive ◽  
Oxygen Tensions ◽  
Human Diploid Cells ◽  
Diploid Cells

We had established that growth of human diploid WI-38 cells is reversibly inhibited by elevated partial pressures of oxygen (PO2) and we were interested in determining where in the cell cycle growth was delayed. A technique combining cytospectrophotometry and autoradiography was used to determine cell cycle parameters. Confluent cells that were subcultivated and exposed to a PO2 of 365 +/- 8 mm Hg were delayed primarily after DNA synthesis but before metaphase. At a PO2 of 590 +/- 35 mm Hg, most cells did not initiate DNA synthesis, and the few that did, failed to complete the process. When exponentially growing cells that had already begun DNA synthesis were exposed to a PO2 of 590 p 35 mm Hg, they accumulated after completing DNA synthesis but before initiating mitosis. The rate at which (3H)thymidine was incorporated into DNA was inversely correlated with oxygen tension (PO2 of 135--590 mm Hg). These results suggest that the process most sensitive to oxygen causes cells to be delayed after DNA synthesis but before metaphase. Slightly higher PO2's were needed to inhibit the initiation of DNA synthesis. Further, the rate of DNA synthesis is decreased by elevated oxygen tensions.

In Vitro Studies of Erythropoiesis

Blood ◽  
1955 ◽  
Vol 10 (6) ◽  
pp. 612-615 ◽  
Author(s):  
E. D. THOMAS
Keyword(s):  
Bone Marrow ◽  
Oxygen Tension ◽  
In Vitro Studies ◽  
Cent Oxygen ◽  
In Vitro Synthesis ◽  
Heme Synthesis ◽  
Rabbit Bone ◽  
Oxygen Tensions ◽  
Effect Of Oxygen

Abstract The effect of various oxygen tensions on the in vitro synthesis of heme by rabbit bone marrow was measured. At levels above 4 per cent oxygen there was no effect of oxygen tension on heme synthesis. Total anoxia stopped heme synthesis completely. No level of oxygen tension was found to stimulate heme synthesis.

Clonal lifespan of Paramecium tetraurelia: effect of selection on its extension and use of fissions for its determination

1987 ◽  
Vol 88 (1) ◽  
pp. 129-138
Author(s):  
Y. Takagi ◽  
T. Nobuoka ◽  
M. Doi
Keyword(s):  
Marked Effect ◽  
Marker Genes ◽  
Paramecium Tetraurelia ◽  
Random Events ◽  
The Mean ◽  
Human Diploid Cells ◽  
Diploid Cells ◽  
Poor Nutrition ◽  
Selection Of

Paramecia cells, like human diploid cells cultured in vitro, provide a useful model system for understanding the mechanism that limits division potential. The reported maxima of the clonal lifespan of Paramecium tetraurelia fall into two ranges: from 220 to 258 fissions and from 310 to 325 fissions. We found that neither the selection of vigorous lines nor the cryptic occurrence of autogamy offers a plausible explanation for the much longer lifespans in the latter range. We found the sporadic occurrence of very long clonal lifespans, such as 330 fissions, without selection and autogamy. Selection, which was evaluated by using different methods to maintain lines, had little effect on the extension of the maximal clonal lifespan, whereas it did have a marked effect on the extension of the mean clonal lifespan. Autogamy, which was checked with two closely linked marker genes, was frequent, but only during the period when lines were terminating. Statistical analysis on the mean clonal lifespans of two groups of subclones cultured at 25 and 20 degrees C or with rich and poor nutrition showed that the clonal lifespan that was fission-related under favourable conditions tended to dissociate from fissions under less favourable conditions. We discuss mechanisms that determine the clonal lifespan, programmed events contributing to the maximum clonal lifespan and random events contributing to the mean clonal lifespan.

Cell-associated pentosidine as a marker of aging in human diploid cells in vitro and in vivo

1998 ◽  
Vol 105 (3) ◽  
pp. 221-240 ◽  
Author(s):  
David R Sell ◽  
Michael Primc ◽  
Irwin A Schafer ◽  
Maureen Kovach ◽  
Miriam A Weiss ◽  
...  
Keyword(s):  
Human Diploid Cells ◽  
Diploid Cells
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