Biomedical subjects
L Parks
Publications and source records attributed to L Parks.
Photoreduction of quinones by isolated spinach chloroplasts.
Explore the source record for details and available documents.
Effects of environmental antiandrogens on reproductive development in experimental animals.
Chemicals that act as androgen receptor (AR) agonists and antagonists or inhibit fetal steroidogenesis can induce reproductive malformations in humans and laboratory animals. Several environmental chemicals disrupt development in rats and/or rabbits at fetal concentrations at, or near, exposure levels seen in some segments of the human population. In rats, fetal tissues concentrations of 10-20 p.p.m. of the DDT metabolite, p,p'-DDE, are correlated with reproductive abnormalities in male offspring. These concentrations are similar to those measured in first-trimester human fetal tissues in the late 1960s. The pesticides vinclozolin, procymidone, linuron and DDT are AR antagonists. They reduce male rat anogenital distance, and induce areolas at relatively low dosages. Hypospadias, agenesis of the sex accessory tissues and retained nipples are seen in the middle dosages, while undescended testes and epididymal agenesis are seen in the highest doses. Phthalate esters (PE) inhibit testosterone synthesis during fetal life, but do not appear to be AR antagonists. Prenatal administration of a single low dose of dioxin (50-1,000 ng TCDD/kg) alters the differentiation of androgen-dependent tissues at p.p.t. concentrations, but the mechanism of action likely involves interaction with a hormone-like nuclear transcription factor, the hormone-like receptor AhR, rather than AR. p,p'-DDT and p,p'-DDE, vinclozolin and di-n-butyl phthalate affect reproductive function in rabbits when administered during prenatal and/or neonatal life. Cryptorchidism and carcinoma in situ-like (CIS) testicular lesions were seen in male rabbits treated during development with p,p'-DDT or p,p'-DDE. Extrapolation of effects from rodents to humans would be enhanced if future studies incorporate determination of tissue concentrations of the active metabolites. Knowledge of the tissue concentrations of the active toxicants also would provide an important link to in-vitro studies, which provide more useful mechanistic information when they are executed at relevant concentrations.
"So that our souls don't get damaged": the impact of racism on maternal thinking and practice related to the protection of daughters.
Racism influences the conceptualization of motherhood and the practice of mothering. Narrative analysis was completed on 246 stories collected through five focus groups. Twenty-five African American women participated in the study. The results indicate that living in a racist society profoundly impacts the maternal thinking and practice of African American women in relation to protecting their daughters. Protection of children was viewed as a communal responsibility. Issues related to the provision of safe and nurturing physical, aesthetic, and spiritual environments are addressed. The influence that maternal responsibilities have on women's own health is also discussed. Suggestions are provided for mental health providers who wish to work more effectively with African American women.
Proceedings; Rejection and repair of endothelium in major vessel transplants.
Explore the source record for details and available documents.