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Biomedical subjects

M J Duffy

Publications and source records attributed to M J Duffy.

At least 127 records · Page 7Linked to original sources
PubMed1978

Multiple steroid receptors in male breast carcinomas.

Specific cytosol receptors for estradiol, progesterone and dihydrotestosterone were detected in human male breast carcinomas. Competition studies with excess unlabelled steroids showed that the receptors were distinct binding proteins. The properties and binding specificity of the estradiol receptor in a male breast carcinoma were very similar to those found in female breast tumors. The possible clinical significance of the presence of steroid receptors in male breast tumors is discussed.

Binding, Competitive↗
PubMed1977

Measurement of estradiol receptors in human breast tumors by polyacrylamide gel electrophoresis.

1. Specific estradiol receptors in cytosols from human breast tumors were measured by discontinuous polyacrylamide gel electrophoresis. 2. Binding of estradiol to contaminating sex hormone binding globulin was clearly separated from that due to the specific receptor. 3. The amount of estradiol bound by the receptor was linear with respect to the amount of protein added to gel. 4. The estradiol receptor peak of radioactivity showed saturability and specificity characteristic of an intracellular receptor. 5. The results show that polyacrylamide gel electrophoresis can be used to quantitate specific estradiol receptors in the presence of other high affinity binding components.

Breast Neoplasms↗
PubMed1977

Estradiol receptors and glucose-6-phosphate dehydrogenase activity in human breast tumors.

Estradiol receptors and glucose-6-phosphate dehydrogenase, an enzyme induced by estrogens, were measured in both benign and malignant human breast tumors. The mean glucose-6-phosphate dehydrogenase activity was higher in the malignant tumors than in the benign tumors. Tumors containing estradiol receptors contained higher activities of glucose-6-phosphate dehydrogenase than tumors without receptors. In breast carcinomas with and without estradiol receptors glucose-6-phosphate dehydrogenase gave 3 isoenzymes with very similar electrophoretic pattern after polyacrylamide gel electrophoresis. The results showed that although glucose-6-phosphate dehydrogenase was higher in estradiol receptor positive than in estradiol receptor negative tumors there was no significant correlation between the estradiol receptor concentration and glucose-6-phosphate dehydrogenase activity in human breast tumors.

Breast Neoplasms↗
PubMed1977

Studies on the labeling of streptokinase with 99mTc for use as a radiopharmaceutical in the detection of deep-vein thrombosis: concise communication.

Streptokinase was labeled with 99mTc using both stannous chloride and stannous pyrophosphate as reducing agents. Sixty to seventy-five percent of the 99m Tc was incorporated into streptokinase using stannous chloride as a reducing agent at pH 1-2, wheras 50-60% was incorporated using stannous pyrophosphate at neutral pH. Increasing the pH from 2 to 7 in the presence of stannous chloride caused the release of 15-20% of the protein-bound 99mTc. Incorporation of 99mTc into protein was relatively slow: labeling required 2-3 hr at room temperature. The concentration of stannous pyrophosphate required for optimum labeling varied between 10(-5) and 10(-2) M. Polyacrylamide-gel electrophoresis showed that the filler substance in commercial streptokinase was also labeled with 99mTc. However pure streptokinase gave a homogenous protein band after polyacrylamide-gel electrophoresis. This protein band coincided with the peak of streptokinase-bound 99mTc. The results obtained may partially explain why 99mTc-labeled streptokinase lacks the necessary specificity for the satisfactory location of blood clots in vivo.

Chromatography, Thin Layer↗
PubMed1975

Stimulation of brain adenylate cyclase activity by the undecapeptide substance P and its modulation by the calcium ion.

Synthetic substance P stimulated adenylate cyclase activity in particulate preparations from rat and human brain. The concentration of substance P for half maximal stimulation in rat brain was 1.8-10-minus 7 M. The stimulatory effect of substance P on the rat brain adenylate cyclase activity was 88% compared with 48% by noradrenalin, 163% by prostaglandin E1 and 184% by prostaglandin E2. Both the basal and substance P-stimulated adenylate cyclase activity in rat brain were inhibited by concentration of Ca-2+ above 10-minus 6 M. The chelating agent ethyleneglycol-bis-(beta-aminoethylether)-N, N'-tetraacetic acid at a concentration of 0.1 mM reduced the basal adenylate cyclase activity by 64% and eliminated the substance P-stimulated activity. The inhibition by ethyleneglycol-bis-(beta-aminoethylether)-N, N'-tetraacetic acid was completely reversed by increasing concentrations of Ca-2+.

Adenylyl Cyclase Inhibitors↗