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Biomedical subjects

E B Thompson

Publications and source records attributed to E B Thompson.

At least 199 records · Page 11Linked to original sources
PubMed1976

Steroid-binding proteins in carcinoma of the human male breast.

Receptor sites for a group of four steroid hormones were estimated by competitive binding assay of a biopsy specimen of carcinoma from a male breast. The results indicate that the tissue contained a significant number of binding sites for 17beta estradiol, and probably for dihydrotestosterone and progesterone, but not for testosterone. These preliminary data suggest that, as in the female, certain mammary carcinomas in the male may be under the influence of steroid hormones. Correlation of such data with responses to therapy may help to establish a more rational approach to the treatment of carcinoma of the male breast.

Binding Sites↗
PubMed1976

Rescue of a rat tropic rat hepatoma virus pseudotype Kirsten sarcoma virus by co-cultivation of hepatoma tissue culture cells with K-NRK cells.

A rat tropic rat hepatoma virus pseudotype Kirsten sarcoma virus has been rescued from a co-culture of rat hepatoma tissue culture cells, HTC-HI, with Kirsten murine sarcoma transformed non-producer rat kidney cells (K-NRK). The virus complex, RHHV-KiMSV, released from the co-culture exhibited cell transformation ability on normal rat kidney (NRK) cells and showed a restricted host range limited to rat embryo fibroblasts and other normal rat cell lines. Evidence derived from indirect immunofluorescence assays demonstrated the association of rat helper virus specific gs-I and gs-3 antigens with RHHV-KiMSV transformed cells. RHHVKiMSV is currently being cultured at a titre as high as 10(4) f.f.u./ml in tissue culture, and thus offering opportunity for biochemical studies of rat viruses.

Animals↗
PubMed1976

Characteristics of cell membranes from somatic cell hybrids between rat hepatoma and mouse L-cells.

Cell membranes from mouse L-cells (L-B82), rat hepatoma (HTC-H1), and three clones of their somatic cell hybrids (07, V4a, and V5) showing different degrees of density-dependent inhibition of growth were analyzed by polyacrylamide gel electrophoresis. The membrane polypeptides of the hybrid clones were all similar and all showed higher proportions of polypeptides with molecular weights of 56,000 and 45,000 than their parents of their normal counterparts. The major glycoprotein form cell hybrids appeared to be identical with that of rat liver or rat hepatoma cells and different from that of L-cells. One hybrid showed density-dependent inhibition growth; the other two, like both parents, did not. All produced tumors in nude mice, although tumor production by the hybrids was delayed. A large external protein (M.W. 240,000) iodinated by lactoperoxidase-catalyzed reaction was virtually missing in the parents but was present at high levels in all their hybrid clones. Thus, there was a lack of correlation between the presence of this protein, growth control in vitro, and tumorigenicity. Furthermore, no correlation was seen between agglutination of these cells by concanavalin A and tumorigenicity. The factors controlling these membrane properties thus are independent of density-dependent inhibition of growth and of those controlling the expression of cancer.

Agglutination↗
PubMed1975

Serum-free growth of HTC cells containing glucocorticoid- and insulin-inducible tyrosine aminotransferase and cytoplasmic glucocorticoid receptors.

HTC cells have been made to grow in chemically defined medium without any macromolecular supplements whatsoever. Initial estimates of their relative amino acid requirements have been made. The cells grown in the defined medium retain many of the differentiated features which have been the focus of investigation in their serum-grown counterparts. Thus, the cells in defined medium contain cytoplasmic glucocorticoid receptors and have tyrosine aminotransferase which can be induced by glucocorticoids, serum or insulin. These cells also produce, in small amounts, an as yet undefined rat serum protein.

Cell Survival↗
PubMed1975

Glucocorticoid binding proteins in myeloblasts of acute myelogenous leukemia.

The myeloblasts of 16 patients with untreated acute myelogenous leukemia were examined for specific glucocorticoid binding proteins. In only 3 of the 16 patients were such high affinity receptors found. The presence of glucocorticoid binding protein activity was positively correlated with inhibition of macromolecular synthesis of myeloblasts in vitro whereas absence of binding protein activity was associated with lack of glucocorticoid inhibition of the cells. Since glucocorticoids appear efficacious in only a small fraction of cases of acute myelogenous leukemia, determination of glucocorticoid binding protein activity may provide assistance in planning chemotherapeutic regimens.

Bone Marrow↗
PubMed1975

Interaction of spironolactone and digitalis with the 5 alpha-dihydrotestosterone (DHT) receptor of rat ventral prostate.

The aldosterone antagonist, spironolactone, has been shown to block the effects of exogenously administered androgen in rat. This suggests that interaction of the drug with androgen at the target tissues may occur. In this paper we have studied the possible interaction of spironolactone with the 5alpha-dihydrotestosterone (DHT)1 receptor of rat ventral prostate. The competitive receptor assay used involves precipitation of the 105,000 X g supernatant of the homogenized tissue with protamine sulfate, removal of the unprecipitated cytosol, and incubation of the precipitate in the presence of the appropriate [3H]DHT steroid solution at 0 C for 18 hours. Using this method the Kd (dissociation constant) for DHT in the rat prostate was in the range of 1.9-4.0 X 10(-9)M and the binding capacity was 0.21 pmol/mg protein. Spironolactone was found to interfere with the binding of DHT to the precipitated cytosol and displayed an estimated Kd of 1.3-4.6 X 10(-8)M. Several digitalis preparations were similarly studied. Digitoxin and digitoxigenin also interfered with the binding of [3H]DHT and had an estimated Kd of 0.8-3.6 X 10(-8)M. Digoxin interacted less strongly and its estimated Kd was 10(-6)M. We believe these results suggest an interaction of spironolactone and digitalis with the DHT receptor and may help explain some of their antiandrogenic actions in the rat and in man.

Animals↗
PubMed1974

Synthesis of glycoproteins in a single identified neuron of Aplysia californica.

Incorporation of L-[(3)H]fucose into glycoproteins was studied in R2, the giant neuron in the abdominal ganglion of Aplysia. [(3)H]fucose injected directly into the cell body of R2 was readily incorporated into glycoproteins which, as shown by autoradiography, were confined almost entirely to the injected neuron. Within 4 h after injection, 67% of the radioactivity in R2 had been incorporated into glycoproteins; at least 95% of these could be sedimented by centrifugation at 105,000 g, suggesting that they are associated with membranes. Extraction of the particulate fraction with sodium dodecyl sulfate (SDS), followed by gel filtration on Sephadex G-200 and polyacrylamide gel electrophoresis in SDS revealed the presence of only five major radioactive glycoprotein components which ranged in apparent molecular weight from 100,000 to 200,000 daltons. Similar results were obtained after intrasomatic injection of [(3)H]N-acetylgalactosamine. Mild acid hydrolysis of particulate fractions released all of the radioactivity in the form of fucose. When ganglia were incubated in the presence of [(3)H]fucose, radioactivity was preferentially incorporated into glial cells and connective tissue. In contrast to the relatively simple electrophoretic patterns obtained from cells injected with [(3)H]fucose, gel profiles of particulate fractions labeled with [(14)C]valine were much more complex.

Animals↗