Search PubMed⌕ Search

Biomedical subjects

R Boyd

Publications and source records attributed to R Boyd.

125 records · Page 7Linked to original sources
PubMed1964

Vasoligation.

Explore the source record for details and available documents.

Humans↗
PubMedDate not supplied

Investigation of mechanisms linking depressed mood to nicotine dependence.

The present study examined the cognitive-behavioral linkages between depressed mood and level of nicotine dependence in smokers seeking smoking cessation treatment. Prior to treatment, 202 subjects completed validated self-report measures of smoking history, depressive symptomatology, "self medication" processes, "learned helplessness" processes, and nicotine dependence. Results revealed that 48% of the study population scored in the "depressed" range on the Center for Epidemiologic Studies (CESD) depression scale. Further, these smokers reported significantly higher levels of nicotine dependence than other nondepressed smokers. Depressed and nondepressed smokers did not differ with respect to several cognitions related to learned helplessness theory. However, depressed smokers were more likely to report "self medication" processes (i.e., negative affect reduction smoking and stimulation smoking). In addition, multivariable regression and path analyses suggested that negative affect reduction smoking and stimulation smoking are sequential mediators of the depression-nicotine dependence relationship. These results underscore the need to screen for depressive symptomatology among smokers seeking treatment, and to develop cessation treatments that are tailored to the needs of depressed smokers.

Adolescent↗
PubMedDate not supplied

Expression of the HPV16E7 oncoprotein by thymic epithelium is accompanied by disrupted T cell maturation and a failure of the thymus to involute with age.

Transgenic mice expressing the E7 protein of HPV16 from the keratin 14 promoter demonstrate increasing thymic hypertrophy with age. This hypertrophy is associated with increased absolute numbers of all thymocyte types, and with increased cortical and medullary cellularity. In the thymic medulla, increased compartmentalization of the major thymic stromal cell types and expansion of thymic epithelial cell population is observed. Neither an increased rate of immature thymocyte division nor a decreased rate of immature thymocyte death was able to account for the observed hypertrophy. Thymocytes with reduced levels of expression of CD4 and/or CD8 were more abundant in transgenic (tg) mice and became increasingly more so with age. These thymic SP and DP populations with reduced levels of CD4 and/or CD8 markers had a lower rate of apoptosis in the tg than in the non-tg mice. The rate of export of mature thymocytes to peripheral lymphoid organs was less in tg animals relative to the pool of available mature cells, particularly for the increasingly abundant CD4lo population. We therefore suggest that mature thymocytes that would normally die in the thymus gradually accumulated in E7 transgenic animals, perhaps as a consequence of exposure to a hypertrophied E7-expressing thymic epithelium or to factors secreted by this expanded thymic stromal cell population. The K14E7 transgenic mouse thus provides a unique model to study effects of the thymic epithelial cell compartment on thymus development and involution.

Aging↗