PubMed Health⌕ Search

Biomedical subjects

E L Coe

Publications and source records attributed to E L Coe.

At least 19 recordsLinked to original sources
PubMed1985

Estrogen receptor expression in serially cultivated rat endometrial cells: stimulation by forskolin and cholera toxin.

Serially propagated with 3T3 feeder layer support, epithelial cells derived from normal rat endometrium expressed estrogen receptor activity. Specific binding of 17-beta-estradiol was in the range of 30-60 fmol/mg of protein and was of high affinity (Kd = 0.3 nM). A survey of cell lines derived from several other normal epithelia showed that rat vaginal and human cervical cultures also had high-affinity estrogen receptors (6-13 fmol/mg of protein), while rat epidermal and esophageal cells had no detectable activity. In the endometrial cultures, receptor levels were elevated nearly two- to fourfold by cholera toxin or forskolin in the medium. This effect was detectable after 4 hr but not 1 hr of treatment and did not occur in the presence of cycloheximide. We conclude that serially cultivated rat endometrial cells retain hormonal properties expressed in vivo while exhibiting some keratinocyte character. These cells may provide a useful model for study of receptor modulation.

Animals↗
PubMed1985

Retinoid suppression of transglutaminase activity and envelope competence in cultured human epidermal carcinoma cells. Hydrocortisone is a potent antagonist or retinyl acetate but not retinoic acid.

Growth of SCC-13 squamous carcinoma cultures in the presence of retinoids considerably reduced the expression of two differentiation markers, the cellular capability to form cross-linked envelopes, and the enzyme transglutaminase required for cross-linking. A limited survey of retinoids showed that all-trans retinoic acid, 13-cis retinoic acid, and arotinoid Ro 13-6298 were highly effective in the absence of hydrocortisone and were only slightly antagonized by its presence in the medium. In contrast, retinyl acetate, retinol, and retinol bound to its plasma binding protein were quite active in the absence of hydrocortisone but were essentially inactive in its presence. Dexamethasone was also highly effective in antagonizing the suppressive action of retinyl acetate on envelope formation, while the corticosteroid antagonists cortexolone and progesterone were inactive. These results suggest that there are separate pathways, which are differentially regulated by hydrocortisone, for either the metabolism or action of retinol and retinoic acid in SCC-13 cells.

Acyltransferases↗
PubMed1983

Mutually antagonistic effects of hydrocortisone and retinyl acetate on envelope competence in cultured malignant human keratinocytes.

Serially propagated SCC-13 keratinocytes, derived from a human squamous cell carcinoma, are greatly influenced by culture conditions in their ability to form ionophore-inducible cross-linked envelopes. Supplementation of the growth medium with fetal bovine serum at concentrations ranging from 0.5 to 20 percent had little effect on competence to form envelopes in confluent cultures. At each serum concentration, however, addition of hydrocortisone to the medium led to an increase in competence of almost fourfold, from approximately 20 to nearly 80 percent. With the serum supplementation held at 5 percent, addition of retinyl acetate to the medium suppressed competence in a concentration-dependent manner over the range of 1 to 100 ng/ml. At the highest concentration employed, competence was reduced over fourfold in the presence of hydrocortisone and virtually eliminated in its absence. When the cells were grown using serum depleted of endogenous vitamin A, a majority were competent in the absence of hydrocortisone. Under this condition, retinyl acetate suppressed competence over fivefold in the absence of hydrocortisone, but not at all in its presence. We conclude that hydrocortisone stimulates envelope competence primarily by antagonizing the suppressive effect of vitamin A. The SCC-13 cell line may prove valuable in studying mechanisms of retinoid and corticosteroid therapeutic action on diseased human keratinocytes.

Carcinoma, Squamous Cell↗
PubMed1977

Fatty acid compositions of lipid fractions from vegetative cells and mature sorocarps of the cellular slime mold Dictyostelium discoideum.

A wild-type strain of Dictyostelium discoideum was grown upon Aerobacter aerogenes. Fatty acid compositions of lipid fractions and of total lipids obtained from vegetative amoebae and mature sorocarps were compared. Fatty acids isolated from vegetative cells were found to include large quantities of 17- and 19-carbon cyclopropane fatty acids while straight-chain, saturated fatty acids represented only 10% (w/w) of total fatty acids. These cyclopropane fatty acids appear to be derived from ingested bacteria and are preferentially incorporated into neutral lipids of the slime mold. Development of amoebae to mature sorocarps is accompanied by a substantial decrease in cyclopropane fatty acid content and a concomitant increase in unsaturated fatty acids, mostly as octadeca-5,11-dienoic acid. The delta-22 stigmastenyl ester fraction is the richest source of this acid. Fully 65% of the fatty acids in this fraction are the octadecadienoate.

Cell Division↗
PubMed1976

Glucose 6-phosphate-dependent binding of hexokinase to membranes of ascites tumor cells.

A pH-dependent, saturable binding of hexokinase isozyme I from Ehrlich ascites carcinoma to plasma membrane and microsome preparations from the same tissue is demonstrated. This binding is enhanced by glucose 6-phosphate and may be considered as the sum of a glucose 6-phosphate-dependent binding and an independent binding. The half saturation concentration of hexokinase is about 0.4 unit per ml for both types of binding, and a maximal binding of 0.5-2.0 units per mg membrane protein is observed for both, although the pH optimum of the independent binding (5.4) is lower than that of the dependent binding (5.9). The half saturation concentration of glucose 6-phosphate required for the dependent binding is 0.05 mM at pH 6.1. 2-Deoxyglucose 6-phosphate competatively reverses the effect of glucose 6-phosphate on binding but does not diminish its inhibition of hexokinase activity.

Animals↗
PubMed1976

Error introduced by small reflection coefficients in permeability constansts obtained by hemolysis.

In 1933, M.H. Jacobs (J. Cell. Comp. Physiol. 4, 161-183) developed the theoretical basis for calculating permeability constants of nonelectryolytes passively penetrating erythrocytes from experimentally determined hemolysis times in isotonic solution of penetrating solute. This derivation had assumed that the reflection coefficient sigma=1, whereas, usually 0 less than sigma less than 1, By comparison of Jacobs' original derivation with the equations revised to include sigma, it is shown that: (see article) where r=(k1/k2), the apparent ratio of solute permeability constant (k1) to osmotic volume flow constant of water (k2) as determined by the Jacobs approach; and ro=(omega/Lpcs), the ratio of the true permeability constant (omega) to the osmotic flow calculated from the product of the pressure-filtration coefficient (Lp) and the concentration gradient (cs). The correct ratio may be expressed as a function of the apparent ratio: (see article) For large or small values of r, simpler approximations may be used: r greater than 1, ro approximately r r less than 1, ro approximately sigma4r These provide less than 20% error if sigma greater than 0.4 and r greater than 10 or r less than 0.1. Corrections for sigma less than 1 are applied to the classical (k1/k2) permeability constants of ethylene glycol, glycerol and propanol for bovine eryghtocytes. The sigma values for monoacetin and diacetin are predicted to be 0.7 and 0.6, respectively, on the basis of the deviation of their (k1/k2) constants from the expected relationship to partition coefficient and vapor pressure.

Animals↗