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Biomedical subjects

E Gaetjens

Publications and source records attributed to E Gaetjens.

At least 37 records · Page 2Linked to original sources
PubMed1979

An improved histochemical method for detection of estrogen receptors in mammary cancer. Comparison with biochemical assay.

Unselected, consecutive surgical specimens from 120 women with cancer of the breast were subjected to histochemical assay for the presence of estrogen receptor. A fluoresceinated bovine serum albumin--estradiol conjugate was used that linked estradiol at position 17 and contained 5 mol fluorescein and 4 mol estradiol per mole albumin. Simultaneous competitive binding studies with excess unlabeled estradiol, diethylstilbestrol, and the antiestrogen nitromifene citrate were regularly performed. Results were compared to those obtained by the dextran-coated charcoal receptor assay. Three specimens were necrotic, two others thawed, and two lacked sufficient protein for biochemical analysis. One specimen did not contain tumor, and 11 others showed a predominant nuclear staining pattern. Nuclear receptor was not assayed biochemically. Comparison of results in the remaining 101 cases showed agreement in 92%. The precedure is uncomplicated, economical, and could be performed and interpreted in any pathology laboratory.

Binding Sites↗
PubMed1979

A histochemical technique for evaluation of progesterone receptors in breast cancer.

A histochemical method for the detection and localization of progesterone receptors in human breast cancer has been developed employing a fluorescein labeled conjugate of bovine serum albumin linked to a progestin as the binding hormone. Considerable tumor cell receptor heterogeneity was apparent and nuclear binding was frequently noted. The results of the new assay correlated with those obtained by dextran-coated charcoal assay in 91 per cent of specimens.

Breast Neoplasms↗
PubMed1978

Immunofluorescent detection of estrogen receptors in breast cancer. Comparison with dextran-coated charcoal and sucrose gradient assays.

Biopsy specimens from 106 women with primary operable, recurrent or metastatic breast cancer were analyzed in a double blind study designed to compare the results of a new fluorescent antibody method for detection of estrogen receptors with estrogen receptors measured biochemically with dextran-coated charcoal and sucrose gradient assay techniques. Assay results correlated in 89.4% of tumors analyzed, and molecular receptor forms (8S and 4S) were accurately predicted in 94.7% of neoplasms studied. Divergent results most often occurred in specimens sparsely populated with malignant cells. The new technique permitted recognition of possible sources of false negative results such as necrosis, absence of tumor and, on occasion, estrogen bound in vivo. It was possible to analyze by the immunofluorescence method two specimens of insufficient size for biochemical assay.

Breast Neoplasms↗
PubMed1978

Production of autoinhibitory factors by mouse lymphoma cells in vitro and its relationship to thiol dependence.

Five different kinds of mouse lymphoma cells conditioned culture medium so that it became inhibitory to thiol-dependent cells but not to thiol-independent cells. Conditioning was rapid and appeared to be complete in 1-3 hr. The inhibitory effects could be reversed by concentrations of 2-mercaptoethanol higher than those usually required for growth promotion. Inhibitory factors were concentrated by ultrafiltration and chromatography on Sephadex G-10 which showed their apparent molecular weights to be 300-600. The factors were stable at 100 degrees and to proteases but were inactivated (after reduction) by iodoacetamide, indicating that they may be thiols or disulfides.

Animals↗
PubMed1978

Detection of androgen and estrogen receptors in human prostatic carcinoma and hyperplasia by fluorescence microscopy.

The histochemical detection of androgen and estrogen receptors in human prostatic tissue was achieved employing fluorescein labeled conjugates of bovine serum albumin linked to testosterone and estradiol. Results were compared to those of dextran-coated charcoal and protamine sulfate assays and correlated in 85% of specimens. Early findings include a relatively uniform distribution of receptor in hyperplastic epithelium in contrast to marked tumor cell receptor heterogeneity in cancer. Location of receptor in nucleus and/or cytoplasm was readily determined.

Adenocarcinoma↗
PubMed1977

Isolation of phosphorylated acid chloroform/methanol-soluble proteins from live frog muscle.

About 6-7% of the total proteins from trichloroacetic acid-washed and freeze-dried frog muscle could be extracted with acid chloroform/methanol. Three of these proteins were found to be phosphorylated in the live frog. They were purified to apparent homogeneity by gel chromatography and preparative gel electrophoresis. The apparent molecular weights, determined by sodium dodecyl sulfate gel electrophoresis, were 34 000, 19 000 and 10 000. Each phosphorylated protein contained 3 mol of a covalently bound neutral sugar but they did not contain any tightly bound lipids. All three proteins incorporated 32P into serine phosphate. The 10 000 dalton protein, which had the highest specific radioactivity contained an unusually high proportion of serine, 14% of the total amino acids. It also did not stain with Coomassie Blue.

Amino Acids↗
PubMed1977

Macromolecular inhibitory factor for lymphoid cells produced by mouse macrophages.

Supernatants of high density cultures of mouse peritoneal macrophages were inhibitory to homologous lymphoid cells in vitro by a number of parameters: proliferation and survival of lymphoma cells was impaired, the immune response of spleen cells to sheep red cells and to Concanavalin A (Con A) was decreased. Inhibition was due to factor(s) with mol. wt of approximately 110,000 as estimated by gel filtration. Activity was stable to heating at 56 degrees, and was resistant to trypsin but not to pronase.

Animals↗
PubMed1976

Isolation of a 32P-labeled polypeptide of low molecular weight from phosphorylated human erythrocyte membranes.

The incorporation of 32P into well washed human erythrocyte membranes was studied in a medium containing [gamma-32P]ATP, Mg2+, and EGTA. Following phosphorylation, the membranes were completely solubilized in 1% sodium dodecyl sulfate and subjected to gel electrophoresis in dodecyl sulfate polyacrylamide. A large incorporation of radioactivity was observed in a band which migrated faster than component 7 (nomenclature of T. L. Steck, (1972), J. Mol. Biol. 66, 295) but slower than the bromophenol blue tracking dye, and did not stain with Coomassie Blue. Isolation of this band by preparative gel electrophoresis revealed that 41% of the radioactivity was associated with a 32P-labeled polypeptide. This polypeptide was further purified by gel chromatography on Sephadex LH-20 in chloroform-methanol-HCl, and Bio-Gel A 1.5m in dodecyl sulfate. Its amino acid composition is characterized by a high content of acidic residues. The calculated minimal molecular weight is 15084. Based upon the recovery of amino acids, the polypeptide fraction comprises at least 1.8% by weight of the total erythrocyte membrane proteins. An apparent molecular weight of 15000 was estimated by gel chromatography in dodecyl sulfate, while a range of 14000-16000 was estimated by electrophoresis in dodecyl sulfate polyacrylamide. The state of phosphorylation of this peptide may reflect a physiological function in the intact red cell.

Amino Acids↗
PubMedDate not supplied

Histochemistry of steroid receptors in breast cancer: an overview.

Immunofluorescence and a new histochemical technique were employed to assay 226 breast cancer specimens for estrogen receptor. Results showed an overall correlation of 91 percent when compared to those of biochemical assays. The histochemical technique is rapid, easy to perform and reveals the same parameters as does immunofluorescence without the need for antiserum. Tumor cell receptor heterogeneity and location of receptor in cytoplasm or nucleus is readily defined by both methods. These histologic tests should prove to be useful in extending the availability of estrogen receptor analysis to all patients with breast cancer.

Breast Neoplasms↗