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Biomedical subjects

E D Plotka

Publications and source records attributed to E D Plotka.

11 recordsLinked to original sources
PubMed1992

Influence of hypothalamic-pituitary-adrenocortical hormones on reproductive hormones in gray wolves (Canis lupus).

The release of hypothalamic-pituitary-adrenocortical hormones was studied in intact and neutered gray wolves (Canis lupus) to determine how these hormones interact and affect reproductive hormones. Experiments were performed on adult wolves anesthetized with 400 mg ketamine and 50 mg promazine. Intravenous (i.v.) injections with 50 micrograms ovine corticotropin releasing factor (oCRF) significantly increased adrenocorticotropin (ACTH; P < or = 0.01), cortisol (CORT; P < or = 0.004), and progesterone (P < or = 0.036), but not beta-endorphin (P > or = 0.52). Since neutered wolves demonstrated dose-dependent elevations in response to ACTH, it was concluded that the progesterone was secreted from the adrenal gland. Basal luteinizing hormone (LH) concentrations in neutered wolves were similar before and 60 min after i.v. injection of 1, 5, or 25 IU ACTH (P > or = 0.36) or 2.2 mg/kg cortisol (P = 0.42). Neither 25 IU ACTH (P = 0.55) nor 0.22 mg/kg dexamethasone (P = 0.49) altered the LH response to injection of LH releasing hormone in neutered wolves. Chronic administration of 0.22 mg/kg/day dexamethasone for 3 d did not alter baseline LH concentrations (P = 0.75). Injection of 1.0 mg/kg naloxone (NAL), however, increased LH concentrations relative to baseline values in both intact (P = 0.032) and neutered (P = 0.0005) female wolves, but not in intact (P = 0.19) or neutered males (P = 0.07). These results indicated that in gray wolves (1) oCRF stimulated the release of pituitary and adrenal hormones in a fashion similar to that of other mammals; (2) the adrenal cortex was capable of secreting progesterone into the systemic circulation; (3) exogenous glucocorticoids did not alter LH concentrations; and (4) endogenous opioids may modulate LH secretion in female wolves.

Adrenal Cortex Hormones↗
PubMed1979

Comparison of estrogen receptor levels in primary and regional metastatic carcinoma of the breast.

The estrogen receptor (ER) level in carcinoma of the breast is a useful predictor of response to hormonal therapy. Metastatic disease may not have the same level of ER as the primary. In a series of 37 patients who had simultaneous ER determination in both primary neoplasm and regional nodal metastasis there was 81% agreement. The true ER character of the tumor would have been missed in seven patients if only the primary tumor had been sampled. The possible reasons for this discrepancy are discussed. We feel that the nodal metastatic deposit may reflect the true nature of the ER status because it represents a purer concentration of tumor cells as well as representing the aggressive element of the tumor.

Axilla↗
PubMed1979

The limited utility of fibrinogen I 125 leg scanning.

Using venography as the reference procedure, this study examined the utility of fibrinogen I 125 scanning for the detection or demonstration of deep venous thrombosis. The results demonstrate the inability of leg scanning to detect accurately the presence or absence of thrombi in the deep venous system. Most striking was the lack of sensitivity of this procedure in areas where the propensity for embolization is greatest. Sensitivity is extremely low in the anatomic areas where leg scanning demonstrates reasonable specificity. The results are nearly identical in the extremity not operated upon. The validity of all prior studies relying heavily or exclusively on 125I leg scans to determine the presence or absence of thrombi must be critically reassessed.

Fibrinogen↗
PubMed1978

Platelet dysfunction associated with cardiopulmonary bypass.

The clinical significance and pathogenesis of the platelet dysfunction following cardiopulmonary bypass were studied in conjunction with the degree of functional impairment associated with the use of membrane and bubble oxygenators. Forty consecutive patients had the following tests preoperatively and postoperatively: complete blood count (CBC), platelet count, prothrombin consumption time, bleeding time, prothrombin time, partial thromboplastin time, fibrinogen, euglobulin clot lysis, fibrin degradation products, and platelet aggregation tests. Six patients were given 14C-serotonin tests before and after operation, and preoperative and postoperative electron micrographs were made of the platelets of 3 patients. The amount of blood lost, the blood transfused, and plasma hemoglobin levels were also measured. Abnormal aggregation of platelets was found, with no difference between the membrane and bubble oxygenators. In vitro aggregation tests with protamine sulfate and hemoglobin solutions, as well as the 14C-serotonin studies and electron micrographs, suggest that platelets acquire storage pool deficiency and an abnormal membrane during cardiopulmonary bypass.

Blood Coagulation Tests↗
PubMed1978

A technique for pinealectomy in deer, with notes on the neuroanatomy.

A technique for removing the pineal gland in adult and young male deer is described. A unilateral craniotomy or craniectomy was performed and the pineal gland was approached by parting the 2 hemispheres of the brain. The blood vessels supplying the pineal gland were coagulated and the gland was removed with forceps. Magnification, microtechniques, fiberoptic illumination, and bipolar coagulation rendered the surgical procedure safe and precise.

Animals↗
PubMed1977

Functional lutein cyst in a postmenopausal woman.

A postmenopausal woman presented with enlarged breasts, increased vaginal mucus, and elevated serum estrogen and normal progesterone levels. A laparotomy was performed and revealed a cystic right ovary. Histologic examination of the ovary demonstrated a cyst lined by stratified lutein cells with abundant eosinophilic cytoplasm. The endometrium showed cystic and adenomatous hyperplasia. The diagnosis was functional lutein cyst. Removal of the cystic ovary reduced the estrogen levels, and the clinical picture reverted to that of a normal postmenopausal state.

Endometrial Hyperplasia↗
PubMed1975

Serum progesterone and estrogens in elephants.

Serum progesterone and estrogens were measured by radioimmunoassay in the serum of immature, mature, and pregnant African and Asian elephants. Progesterone was elevated from 26 to 215 pg/ml in nonpregnant animals and up to 480 pg/ml in late pregnancy animals. No relationship to reproductive state was evident for the low levels of estrogens which ranged from 9 to 37 pg/ml.

Africa↗
PubMed1975

Periovulatory changes in peripheral plasma progesterone and estrogen concentrations in the mare.

Concentrations of progesterone and estrogen were measured in peripheral blood plasma samples from mares around the time of ovulation. Samples were collected every 2 hours from 36 hours before, to 26 hours after, ovulation and assayed by radioimmunoassay. Progesterone concentrations were between 60 and 100 pg/ml for the period 24 hours before ovulation through 8 hours after ovulation. By 10 hours after ovulation, concentrations increased to 140 pg/ml and, by 26 hours after ovulation, reached 346 pg/ml. Plasma estrogen concentrations did not change significantly throughout the same period.

Animals↗