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Biomedical subjects

M T Williams

Publications and source records attributed to M T Williams.

59 records · Page 4Linked to original sources
PubMedDate not supplied

Elevations in plasmatic titers of corticosterone and aldosterone, in the absence of changes in ACTH, testosterone, or glial fibrillary acidic protein, 72 h following D,L-fenfluramine or D-fenfluramine administration to rats.

Studies in both humans and animals demonstrate that D,L- and D-fenfluramine (D,L-FEN and D-FEN, respectively) can activate the hypothalamic-pituitary-adrenal axis following an acute dose. No data exist showing a prolonged effect of either drug, although two studies have hinted at increased adrenal activity. There are also considerable differences in the literature pertaining to the neurotoxic effects of D,L- and D-FEN. Some possible explanations for these differences include: activation of different neurotransmitter systems, the temperature at which the animals were maintained during exposure, or the substance sampled in each study. We investigated the effects of either D,L-FEN or D-FEN on pituitary, adrenal, and gonadal hormones 72 h after drug exposure. Furthermore, using a dosing regimen adapted from studies on methamphetamine (e.g., four times every 2 h in a single day) known to produce elevations in glial fibrillary acidic protein (GFAP) under hyperthermic conditions, we examined the effects of D- and D,L-FEN (15 mg/kg, four times) on GFAP content when the animals were dosed at ambient temperatures of 21 or 32 degrees C. Approximately fivefold increases of corticosterone and threefold increases of aldosterone were found 72 h later under resting conditions following both D- and D,L-FEN. Nonetheless, when animals were dosed with D-FEN at 32 degrees C, no significant elevation in corticosterone was detected. No effect was observed for ACTH, testosterone, or GFAP following D- or D,L-FEN treatment. These data suggest that: (1) FEN treatment causes prolonged elevations in adrenal cortical hormones; (2) FEN-treated animals displayed hormonal characteristics similar to animals undergoing a chronic stressor as suggested by no difference in ACTH titers; (3) D,L-FEN treatment or D-FEN treatment (as reported previously) is not similar to other substituted amphetamines in that it does not increase GFAP, even under hyperthermic conditions.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Changes in the hormonal concentrations of pregnant rats and their fetuses following multiple exposures to a stressor during the third trimester.

Human and animal studies indicate that stress during pregnancy can exert long-term effects on the development of the offspring, effects that appear to be mediated in part by the hypothalamic-pituitary-adrenal (HPA) axis. In this experiment changes in levels of a variety of HPA and other hormones in both pregnant rats and their fetuses were investigated. Trunk blood was collected from pregnant females and fetuses following repeated 45-min presentations of restraint, bright lights, and heat during the third trimester. In addition, testes were harvested from the male fetuses. Hormone concentrations were determined by radioimmunoassay. Pregnant females had elevated titers of plasma corticosterone, aldosterone, and ACTH for approximately 15 min following termination of the stressor. No differences were found for beta-endorphin or prolactin. Fetuses showed a pattern of changes in plasma corticosterone and aldosterone that was similar to that of pregnant females, but no effect was observed for fetal ACTH titers. These results are consistent with a role of the HPA axis in the effects of gestational stress. Testicular levels of CRF on gestational day 21 were lower in fetuses of stressed females than in those of nonstressed females. The reduced levels of testicular CRF suggest that CRF may be involved in the altered pattern of sexual differentiation of males stressed during gestation.

Adrenal Glands↗
PubMedDate not supplied

Stress during pregnancy alters the offspring hypothalamic, pituitary, adrenal, and testicular response to isolation on the day of weaning.

Subjecting pregnant female rats to situations that activate the hypothalamic-pituitary-adrenal (HPA) axis can have long-term effects on the development of the offspring. Restraint under bright lights is a common method of stressing pregnant females that results in consistent behavioral changes in the offspring. We investigated the effects of gestationally administered restraint, bright lights, and heat on the HPA axis response of 21-day-old offspring following exposure to isolation in a novel environment or under resting conditions. Corticotropin-releasing factor titers in the hypothalamus were unaffected following isolation. Nonetheless, adrenocorticotropin hormone (ACTH) was found to be lower in the gestationally stressed offspring prior to or following the isolation period. Corticosterone was attenuated in gestationally stressed offspring following the postnatal stressor and there was also a tendency for the gestationally stressed females to have lower concentrations of aldosterone. Plasmatic testosterone levels were higher in the gestationally stressed males following the period of isolation. The present data suggest that the HPA axis of the offspring is differentially affected by the gestational stress procedure, that is, it is attenuated at the level of the pituitary and adrenal, but not at the level of the hypothalamus. These data have implications for behavioral differences observed in gestationally stressed animals.

Adrenocorticotropic Hormone↗
PubMedDate not supplied

Screening for second cancers and osteoporosis in long-term survivors.

PURPOSE: The purpose of this preliminary study was to describe the extent to which healthcare providers recommend the screening strategies for early detection described by the American Cancer Society (ACS), for breast, gynecologic, and colorectal cancer, and by the National Osteoporosis Foundation (NOF), for osteoporosis, to women who are long-term survivors of breast, ovarian, or endometrial cancer. DESCRIPTION OF THE STUDY: A four-part survey was developed for this study, with the first three parts based on the ACS guidelines for breast, gynecologic, and colorectal cancer screening and the NOF guidelines for osteoporosis screening. The fourth part related to personal characteristics, setting, knowledge, and perceptions of the nurses surveyed. A random sample of outpatient nurses was obtained from the Oncology Nursing Society. Of 668 nurses, 321 (48%) responded (Oncology Certified Nurse (OCN) 68.1%; Advanced Oncology Certified Nurse (AOCN) 16.6%). RESULTS: The most consistently performed screenings that were reported were mammogram (range 74.2-87.7%), professional breast examination (range 73.9-83.7%), and Pap test and pelvic examination (range 61.8-85.2%). The least frequently performed screenings are flexible sigmoidoscopy/colonoscopy (range 20.2-27.7%), bone mineral density testing (range 16.9-19.0%), and height measurement (range 22.5-28.3%). Less than one third of survivors are offered counseling on strategies to promote bone health. CLINICAL IMPLICATIONS: Knowledge of factors associated with osteoporosis and the use of screening strategies for second malignancies in survivors of breast, ovarian, and endometrial cancers can be used to implement activities such as patient education and clinical practice protocols that will increase the use of current screening recommendations.

Attitude of Health Personnel↗