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Biomedical subjects

D B Goodman

Publications and source records attributed to D B Goodman.

At least 109 records · Page 6Linked to original sources
PubMed1978

Oxygen-sensitive stages of the cell cycle of human 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.

Cell Cycle↗
PubMed1978

8-P-Chlorophenylthio-cyclic AMP: a potent partial simulator of antidiuretic hormone action.

In the toad urinary bladder 8-p-chlorophenylthio-cyclic AMP mimics the stimulatory effects of antidiuretic hormone on osmotic water permeability, 3H2O diffusion, and transepithelial sodium transport; but unlike the hormone does not cause an increase in urea permeability. Trheshold activation for the hydroosmotic response is observed at 1 micrometer and full activation at 100 micrometer. These results suggest that cyclic AMP may not mediate all the physiological effects of antidiuretic hormone and that this highly potent cyclic AMP analog may be useful in elucidating the precise role of cyclic AMP in other biomediate hormone action.

Animals↗
PubMed1977

Effect of ionophore A23187 upon membrane function and ion movement in human and toad erythrocytes.

Addition of 0.1-0.3 micronM A23187, a divalent cation ionophore, to human erythrocytes suspended in a 1.0 mM 45Ca2+ -containing buffer results in a small (approximately two fold) increase in [Ca2+]i, a significant decrease in osmotic fragility, and a decrease in intracellular K+ (100 mmoles/liter of cells to 70 mmoles/liter cells) without significant alteration of intracellular [Na+]. This decrease in [K+]i is associated with a significant decrease in packed cell volume and correlates directly with the observed alteration is osmotic fragility. Increasing extracellular K+ to 125 mM prevents the A23187-induced changes in osmotic fragility, K+ content and cell volume, but does not prevent the ionophore-induced uptake of 45Ca2+. Addition of 0.1-0.3 micronM A23187 to toad erythrocytes leads to an increase in 45Ca2+ uptake comparable to that observed in human erythrocytes, but does not alter osmotic fragility, cell volume or K+ content. Higher concentrations of ionophore (3.0-10.0 micronM) cause a 30- to 50-fold increase in 45Ca2+ uptake and concomitant change in K+ content, cell volume and osmotic fragility. These changes in cell properties can be prevented by increasing extracellular [K+] to 90 mM. The difference in sensitivity of the two cell types to A23187 is attributed to the presence of additional intracellular calcium pools within toad erythrocytes that prevent an increase in cytoplasmic Ca2+ until Ca2+ uptake is increased substantially at the higher concentrations of A23187.

Adenosine Triphosphate↗
PubMed1977

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

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).

Cell Division↗
PubMed1977

Lipid metabolism in regressing rat corpora lutea of pregnancy.

Lipid accumulation is a hallmark of corpus luteum regression and we characterized lipids stored in rat corpora lutea of pregnancy between days 21 and 24 post coitum, the period of luteolysis. A 10-fold rise in lutein triglyceride concentrations occurred between days 21 and 24, which represented the major alteration in luteal lipid metabolism during luteolysis, coinciding with the appearance of numerous lipid droplets in the luteal cells. The fatty acid composition of luteal triglycerides was altered between days 20 and 23 in a pattern consistent with the influx of blood triglyceride fatty acids. No evidence for increased de novo fatty acid synthesis by luteal tissue between days 21 and 24 post coitum was obtained using in vitro methods. [14C]Acetate incorporation into lipids declined between days 16 and 24 and label was preferentially introduced into long chain polyunsaturated fatty acids. Rates of tritium incorporation into fatty acids from tritiated water were relatively low. [14C]Glucose was predominantly incorporated into the glycerol moiety of luteal lipids and incorporation of label into this fraction was augmented between days 21 and 23 post coitum. The incorporation of [14C]palmitate into triglycerides of luteal tissue during in vitro incubation also increased between days 21 and 23. In vitro lactate production, [14C]glucose oxidation, and [14C-palmitate oxidation to 14CO2 increased significantly during this time. We conclude that specific biochemical alterations occur in regressing corpora facilitating uptake and storage of blood glyceride fatty acids as triglycerides. The physiological significance of this triglyceride accumulation remains to be elucidated.

Acetates↗
PubMed1976

Cholelithiasis in persons under 25 years old. Clinicopathologic review of 96 cases.

Ninety-six of 683 patients undergoing cholecystectomy at the Naval Regional Medical Center, Long Beach, Calif, from 1967 to 1974 were between 7 and 25 years old. Although females predominated in ratio of 4:1, the sex incidence was equal when nulliparous females were compared with males. Signs and symptoms were nonspecific in 70%, leading to delay in proper diagnosis in 26%. Only two patients had an underlying blood dyscrasia. Oral cholecystography proved to be the most reliable diagnostic test. Moreover, the incidence of choledocholithiasis was 4.1%, approximately one third less than in older age groups.

Adolescent↗
PubMed1976

Calcium-dependent stimulation of erythrocyte membrane phospholipid fatty acid incorporation by the ionophore A23187.

Treatment of human erythrocytes with A23187, a divalent cation ionophore, results in a calcium-dependent increase in the rate of incorporation of palmitic, oleic, and linoleic acids into phosphatidylethanolamine. Incorporation of fatty acids into phosphatidylcholine is unaffected by A23187. This calcium-dependent stimulation of membrane phosphatidylethanolamine fatty acid turnover by A23187 may be related to the changes in erythrocyte membrane function induced by A23187 that have been observed previously.

Anti-Bacterial Agents↗
PubMed1976

Effects of inhibitors of protein and RNA synthesis on aldosterone-stimulated changes in phospholipid fatty acid metabolism in the toad urinary bladder.

The effects of an inhibitor of RNA synthesis, cordycepin, and an inhibitor of protein synthesis, cycloheximide, on aldosterone-induced changes in lipid metabolism and phospholipid fatty acid composition have been studied in the toad urinary bladder. At the concentrations employed, the inhibitors abolish the hormone-induced increases in total lipid synthesis, phospholipid fatty acid specific activities, and weight percentage of phospholipid long-chain polyunsaturated fatty acids as well as blocking the aldosterone-mediated increase in sodium transport.

Acetates↗
PubMed1976

Atmospheric stability in cell culture vessels.

We have investigated that atmospheric stability in polystyrene and glass cell culture vessels by measuring the dissolved O2 and CO2 in the media of both seeded and unseeded culture vessels incubated at 37 degrees C. There was no diffusion of either O2 or CO2 through glass vessels. At low partial pressures of oxygen (PO2), oxygen diffused into the polystyrene flasks at a rate of 1 to 2 mmHg per 24 hr, and at high PO2, oxygen diffused slowly out of polystyrene flasks. CO2 diffused out of polystyrene flasks with a half-time of 260 hr resulting in a considerable elevation in pH. In seeded polystyrene flasks with the PO2 less than or equal to room air, cellular oxygen consumption was masked by the inward diffusion of oxygen. In addition, the fall in pH due to metabolic CO2 and organic acid production during cell growth in polystyrene flasks was buffered by the diffusion of CO2 out of the vessels.

Carbon Dioxide↗
PubMed1976

Calcium ion as second messenger.

The role of calcium as an intracellular messenger in the activation of eukaryotic cells is discussed. Particular emphasis is devoted to: (1) the interrelationship between cell activation by chemical stimuli and alterations in intracellular calcium metabolism, and (2) the interrelated roles of calcium and the cyclic nucleotides, cyclic AMP and cyclic GMP, in achieving the final integrated, co-ordinated cellular response.

Adenylyl Cyclases↗
PubMed1975

Effects of an acetyl-coenzyme A carboxylase inhibitor and a sodium-sparing diuretic on aldosterone-stimulated sodium transport, lipid synthesis, and phospholipid fatty acid composition in the toad urinary bladder.

A correlation study of the effects of two agents, 2-methyl-2-[p-(1,2,3,4-tetrahydro-1-naphthyl)phenoxy]propionic acid (TPIA) and amiloride, on aldosterone-induced alterations in Na+ transport, lipid synthesis, and phospholipid fatty acid composition has been carried out in the toad urinary bladder. TPIA, an inhibitor of acetyl-CoA carboxylase, inhibits aldosterone-stimulated Na+ transport as well as hormone-induced lipid synthesis and the increase in weight percentage of phospholipid long-chain polyunsaturated fatty acids. Amiloride, a diuretic which blocks sodium entry into the transporting epithelium, does not alter aldosterone's effects on lipid and fatty acid metabolism but prevents the hormone-induced increase in Na+ transport. These results support the conclusion that aldosterone increases Na+ transport in the toad urinary bladder by altering membrane fatty acid metabolism and that the lipid biosynthetic events following aldosterone treatment are a primary response to the hormone and not secondary to increased Na+ transport.

Acetates↗
PubMed1975

Immunofluorescent localization of cyclic AMP in toad urinary bladder: possible intercellular transfer.

By use of an immunofluorescent cytochemical staining technique, adenosine 3',5'-monophosphate (cyclic AMP) has been localized in toad bladder epithelial cells. Within 2 minutes after addition of vasopressin, staining intensity increases in both mitochondria-rich and granular cells. This finding, taken together with the precise anatomical relation between these two epithelial cell types and the observation that after separation of the two cell types vasopressin stimulates cyclic AMP accumulation in only mitochondria-rich cells, suggests that cyclic AMP may be transferred from mitochrondria-rich to granular cells as part of the response of the toad urinary bladder to vasopressin.

Animals↗
PubMed1975

Aldosterone-Induced Membrane Phospholipid Fatty Acid Metabolism in the Toad Urinary Bladder.

Aldosterone action in the isolated toad urinary bladder has been studied by incubation of the tissue with several specifically labeled lipogenic precursors. Within 30 min after hormone addition phospholipid synthesis is stimulated; the metabolism of oleic acid is particularly enhanced. Additionally, during this time interval a phospholipid deacylation-reacylation cycle is stimulated by aldosterone.

Acetates↗