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Biomedical subjects

S A Shain

Publications and source records attributed to S A Shain.

68 records · Page 4Linked to original sources
PubMed1975

Spontaneous adenocarcinomas of the ventral prostate of aged A X C rats.

Spontaneous adenocarcinomas of the ventral prostate were present in 7 of 41 aged (34- to 37-month-old), virgin, untreated male A X C rats. The only consistent gross evidence of possible neoplastic involvement was intraprostate hemorrhage. The principally intraglandular neoplasms were composed of markedly anaplastic epithelial cells which retained a moderate propensity to form glandular patterns. The nuclei of the neoplastic cells were pleomorphic, vesiculated, enlarged, and hyperchromatic. Mitotic figures were frequent. Interglandular connective tissue was invaded in one rat; however, metastases were not demonstrated.

Adenocarcinoma↗
PubMed1975

Oncorna-like viruses in baboon prostate tissue.

Oncorna-like virus particles were observed in prostate tissue of 2 of 11 baboons inoculated 3 years previously with a chemical carcinogen. There were no indications, however, of any relationship between the carcinogen and the development of virus particles. Biopsy specimens from the animals showed no evidence of neoplasia, and electron microscopic examination suggested that this virus should be categorized as a B-type oncornavirus.

9,10-Dimethyl-1,2-benzanthracene↗
PubMedDate not supplied

Hormone receptors of the baboon cardiovascular system. Biochemical characterization of aortic cytoplasmic androgen receptors.

Cytoplasmic androgen receptors were identified in the aorta of the baboon (Papio sp.). Using the synthetic androgen R1881 (17 beta-hydroxy-17 alpha-methyl-estra-4,9,11-trien-3-one) as probe, androgen receptors were demonstrated only when the incubation mixtures contained 1.0 microM triamcinolone acetonide (TA). The relative binding affinity of selected steroids for the aortic androgen receptor was R1881, 100%; 5 alpha-dihydrotestosterone, 46.1%; testosterone, 60.7% progesterone, 9.1%; R5020, 3.1%; and estradiol-17 beta, 7.5%. THe androgen receptor migrated on low-ionic-strength linear sucrose density gradients as a macromolecule with a sedimentation coefficient of 8.0S. Saturation analysis performed at 2 degrees C (available sites) showed that the androgen receptor content a baboon aortic cytoplasmic extracts was 12.9 +/- 2.4 fmoles/mg protein and that the dissociation constant for R1881 was 1.47 +/- 0.07 nM. The observation that TA was required in the cytoplasmic extracts in order to identify androgen receptors indicates the presence of progesterone receptor-like binding components. These aortic cytoplasmic androgen receptors are indicated to be physiologically functional by previous autoradiographic studies that showed localization of radioisotope in the nuclei of aortic smooth muscle cells following injection of baboons with 5 alpha-dihydrotestosterone.

Animals↗
PubMedDate not supplied

Androgen directs apparent cytoplasmic and nuclear distribution of rat cardiovascular androgen receptors.

We used either the synthetic androgen R1881 (methyltrienolone) or 5 alpha-dihydrotestosterone (5 alpha-DHT) to characterize androgen receptors in rat aortic and myocardial cytoplasmic and nuclear preparations. Relative steroid specificity studies established that only androgens were effective inhibitors of R1881 (cytoplasmic) or 5 alpha-DHT (nuclear) binding to aortic and myocardial androgen receptors, whereas estrogens, progestins, and cortisol were ineffective inhibitors. Low ionic strength sucrose density gradient centrifugation analyses showed that androgen receptors in aortic and myocardial cytoplasmic preparations migrated as macromolecules with sedimentation coefficients of 8 to 9S, whereas androgen receptors in aortic and myocardial nuclear preparations migrated as macromolecules with sedimentation coefficients of 4 to 5S (high ionic strength buffer). Saturation analyses established that aortic and myocardial cytoplasmic preparations from intact, untreated young mature female rats contained 45.8 +/- 9.7 (mean +/- SD) and 63.3 +/- 20.7 fmol androgen receptor/mg DNA, respectively. The respective R1881 dissociation constants were 0.60 and 0.32 nM. Androgen receptors could not be demonstrated in nuclear preparations from the cardiovasculature of intact females. Testosterone injection of intact young mature female rats caused apparent depletion of androgen receptors in aortic and myocardial cytoplasmic preparations and resulted in concomitant appearance of 57.1 +/- 22.2 and 52.3 +/- 21.5 fmol receptor/mg DNA in the corresponding nuclear preparations. The respective 5 alpha-DHT dissociation constants were 4.46 and 1.63 nM. The ability of testosterone to affect apparent intracellular distribution of cardiovascular androgen receptors suggests that the receptors are physiologically functional and indicates that androgen may directly regulate cardiovascular cell function.

Androgens↗
PubMedDate not supplied

Estrogen-mediated cytoplasmic and nuclear distribution of rat cardiovascular estrogen receptors.

We used either the synthetic estrogen R2858 (moxestrol) or estradiol-17 beta to characterize estrogen receptors in cytoplasmic (R2858) and nuclear (estradiol-17 beta) preparations from rat aorta and myocardium. Relative steroid specificity studies showed that only estrogens were effective inhibitors of R2858 or estradiol-17 beta binding to aortic and myocardial estrogen receptors, whereas androgens, progestins, and cortisol were ineffective inhibitors. Low ionic strength sucrose density gradient analyses showed that myocardial estrogen receptors that localized in the cytoplasmic fraction migrated as macromolecules with sedimentation coefficients of 8S to 9S. In contrast, two binding components of sedimentation coefficients 8S to 9S and 10S to 11S were characteristic of the estrogen receptors localized in aortic cytoplasmic preparations. High ionic strength sucrose density gradient analysis showed that aortic and myocardial estrogen receptors localized in the nuclear fraction migrated as macromolecules with sedimentation coefficients of 4S to 6S. Saturation analyses showed that aortic and myocardial cytoplasmic preparations from intact young mature male rats contained 50.6 +/- 12.9 (mean +/- SD) and 51.0 +/- 14.1 fmol receptor/mg DNA, respectively. The respective R2858 dissociation constants were 0.42 and 0.15 nM. Estrogen receptors could not be demonstrated in nuclear preparations from cardiovasculature of intact males. Estradiol-17 beta injection of intact young mature male rats caused "depletion" of aortic and myocardial cytoplasmic fraction estrogen receptors and resulted in the appearance of 51.9 +/- 21.0 and 36.9 +/- 9.5 fmol receptor/mg DNA in the corresponding nuclear fractions. The respective estradiol-17 beta dissociation constants were 1.56 and 0.71 nM. Increased estrogen receptor content of cardiovascular nuclear fractions of estradiol-17 beta injected male rats correlated well with the concomitant decreased cytoplasmic fraction receptor content. The ability of estradiol-17 beta to affect localization of cardiovascular estrogen receptors between cytoplasmic and nuclear fractions suggests these estrogen receptors are physiologically functional and indicates that estrogen may directly regulate cardiovascular cell function.

Animals↗
PubMedDate not supplied

Estradiol-17 beta affects estrogen receptor distribution and elevates progesterone receptor content in baboon aorta.

We used the synthetic estrogen R2858 (moxestrol) and estradiol-17 beta, respectively, to characterize the estrogen receptor in baboon (Papio sp.) aortic or myocardial cytoplasmic and nuclear preparations. We observed regional differences in the cytoplasmic fraction estrogen and progesterone receptor content of aortic arch, thoracic aorta, and abdominal aorta when tissues from either oophorectomized or oophorectomized estradiol-17 beta-treated subjects were compared. The estrogen receptor content was highest in the abdominal aorta and lowest in the aortic arch. In contrast, the cytoplasmic fraction progesterone receptor content was highest in the aortic arch and lowest in the abdominal aorta. The nuclear fraction estrogen receptor could not be demonstrated in preparations from cardiovasculature of oophorectomized female baboons. The use of Silastic implants to administer a physiologic concentration of estradiol-17 beta to oophorectomized female baboons caused a 20% to 50% reduction in cytoplasmic fraction estrogen receptor content, which was quantitatively accounted for by the appearance of estrogen receptor in the corresponding nuclear aortic or myocardial preparation. Estrogen administration caused a 20% to 40% increase in cytoplasmic fraction progesterone receptor content in both myocardium and aorta; however, differences were significant only for abdominal aorta (p less than 0.05). Estradiol-17 beta treatment caused a tenfold increase in uterine cytoplasmic fraction progesterone receptor content in treated as compared to oophorectomized control females, suggesting that baboon cardiovasculature is less sensitive to changes in endogenous estrogen concentration than is uterus. The ability of estradiol-17 beta to affect apparent intracellular distribution of baboon cardiovascular estrogen receptors and to elevate cytoplasmic fraction progesterone receptor content suggests that these estrogen receptors are physiologically functional and indicates that estrogen may directly regulate primate cardiovascular cell function.

Animals↗
PubMedDate not supplied

Gender and baboon aortic steroid hormone receptors.

To examine the potential of steroid hormones to serve as putative regulators of aortic cell function, we defined hormone receptor content and distribution in intact baboons. Total androgen receptor content in baboon aortic arch, thoracic arch, and abdominal aorta of young mature males was indistinguishable from that of proestrus females. However, 30% to 40% of male aortic androgen receptors were in the nuclear fraction, whereas all aortic androgen receptors of proestrus females were in the cytoplasmic fraction. Cytoplasmic fraction estrogen receptor content of aortic arch and thoracic aorta of intact males was indistinguishable from that of proestrus females. However, cytoplasmic fraction estrogen receptor content of abdominal aorta of proestrus females was significantly greater than that of males. Nuclear fraction estrogen receptors were not detectable in either male or proestrus female baboon aortas. To assess effects of endogenous estrogen on aortic progesterone receptor content, we quantified cytoplasmic fraction progesterone receptors and found that content of proestrus female aortic arch was not significantly different from that of males. However, cytoplasmic fraction progesterone receptor content of thoracic and abdominal aorta of proestrus females was significantly higher than that of males. To determine whether differences in aortic receptor content or distribution were associated with changes in aortic cell function, we quantified the activity of two enzymes of glycosaminoglycan metabolism. Aortic beta-glucuronidase activity was not different in male or proestrus female baboons.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗