Elaine Dillon

Psychologic characteristics associated with acute stressor-induced leukocyte subset redistribution

This study examined relationships between psychologic characteristics and enumerative immune responses to an acute laboratory stressor. Lymphocyte subsets were measured in 104 subjects at rest and following a 6-minute laboratory naturalistic speaking stressor. Multiple linear regression was utilized to assess relationships between immune reactivity (change scores) and anger expression, hostility, anxiety, depression, and stress. The task resulted in significant increases over baseline in WBC (p < 0.001), T-suppressor/cytotoxic CD8 cells (p = 0.010) natural killer CD56 cells (p < 0.0001), and CD57 (p < 0.0001) cells, and significant decreases in T-cells (p = 0.012), T-helper cells (p = 0.003), B-cells (p < 0.001), and the T-helper/suppressor ratio (p < 0.001). In general, the regression suggested that moderate associations exist between certain psychologic attributes and acute subset redistribution. For example, the increase in natural killer cell subsets was significantly negatively associated with anger expression, hostility, and depression. Suppressor/cytotoxic (CD8) cell reactivity was associated with baseline as well as with the task-induced changes in anxiety. B-cell (CD19) responses were related to the subjects age, expression of anger, and depression scores. As with the cardiovascular reactivity literature, these findings suggest that a relationship exists between certain psychologic characteristics such as anger and anxiety and immune reactivity to acute stress.

Effects of chronic stress on beta-adrenergic receptors in the homeless

&NA; This study examined the role of chronic life stress (homelessness), coping style, and hypertension on beta‐adrenergic receptors in a sample of homeless men. Sixteen healthy normotensive subjects and nine untreated hypertensive subjects were studied. Life stress was measured with the Brown and Harris categorization; coping style was measured with the Ways of Coping Scale. Lymphocyte beta‐adrenergic receptors were characterized in terms of receptor density (Bmax). Individuals with high life stress had lower Bmax (p < .005). In multiple regression analyses, 50% of the variance in Bmax was accounted for by life stress and coping style (p = .01). Receptor measures may be useful for characterizing the physiological response to continuing life adversity.

Catecholamines in human saliva

Catecholamines are readily detectable in human saliva but their origin is unclear. Norepinephrine (NE) was stable in saliva stored at 4 degrees for 2 hours but 11 +/- 3% degraded after storage at 25 degrees for 1 hour. We intravenously infused 3H-NE into humans and measured levels of 3H-NE and its metabolites in both saliva and forearm venous plasma (a site whose plasma NE levels reflect both local uptake and release of NE). 3H-NE levels in saliva continued to rise for 1 hour even though forearm plasma levels had plateaued by 5 min. By 65 min into the infusion the ratio of 3H-NE:non-radioactive NE was similar in saliva and forearm venous plasma. The ratio of NE:epinephrine (E) was similar in saliva and forearm venous plasma at all time points. Chewing induced salivation, and at least tripled the amount of NE, E and 3H-NE released into saliva per minute, but decreased their concentration in saliva by as much as one half. Saliva NE level was unaltered after 15 min of standing but was increased by 31% after 1 hour of upright posture. Our data imply that the NE present in human saliva comes from both the bloodstream and from salivary sympathetic nerves. The finding that diffusion of blood NE into saliva takes roughly 1 hour to complete suggests that NE in saliva is a poor index of acute changes in sympathetic activity.

L-Selectin Expression Affects T-Cell Circulation Following Isoproterenol Infusion in Humans

beta-Adrenergic receptor agonists have been shown to affect leukocyte migration. This study examined the expression of cellular adhesion molecules on lymphocyte, monocyte, and granulocyte distribution following an infusion of isoproterenol (20 and 40 ng/kg/min for 15 min each) in 12 healthy subjects. Leukocyte populations and adhesion molecule expression were determined via flow cytometry. Isoproterenol led to an expected lymphocytosis and leukocytosis. L-selectin expression varied across leukocytes and influenced cell trafficking in response to isoproterenol. Approximately 60% of CD8+ T-cells expressed L-selectin (CD8+CD62L+) and these cells showed no appreciable response to isoproterenol. In contrast, CD8+CD62L- cells showed a robust increase in number and distribution of approximately 100% over baseline (ps < .001). Across CD4+ T-helpers, L-selectin was expressed on approximately 86% of cells. CD4+CD62L+ cells decreased in number and distribution (ps < .001) with isoproterenol, while CD4+CD62L- cells showed a modest increase (ps < or = .05). In contrast to lymphocytes, nearly all monocytes and granulocytes expressed L-selectin; these cells increased and decreased respectively in response to isoproterenol (ps < or = .05). CD11a (the beta 2-integrin LFA-1) was expressed on > 95% of all leukocytes and these data were thus similar to the overall leukocytosis data. CD54 (ICAM-1) was expressed on approximately 60% of mixed lymphocytes and was unchanged in response to isoproterenol. The findings indicate that L-selectin expression influences T-cell trafficking in response to beta-adrenergic stimulation and help further illuminate catecholamine-mediated sympathetic and immune interactions.

Race and sex differences in cardiovascular recovery from acute stress

To evaluate the effects of race and gender on recovery, i.e. the relative return to baseline after a stress challenge, cardiovascular and catecholamine measures were examined before, during and after two standardized laboratory stressors (a speaking and a mirror tracing task) in a group of 85 Black and White men and women (mean age 35.6 years, range 20 to 52). For the speech task, White men showed the least systolic (p < 0.025) and diastolic (p < 0.05) blood pressure recovery as compared to Black men and women. For the mirror star tracing task, total peripheral resistance (p < 0.03) recovery was least for Whites as compared to Blacks and heart rate (p < 0.04) recovery was least for White women as compared to Black women and men. There were no significant group effects in terms of catecholamine recovery from either task. The findings extend prior studies on race and gender by suggesting that these same characteristics affect recovery from stressors.

Menstrual Cycle Effects on Catecholamine and Cardiovascular Responses to Acute Stress in Black but Not White Normotensive Women

This study examined cardiovascular and catecholamine responses to two standardized laboratory stressors in 33 healthy age- and weight-matched black and white normotensive women (mean age, 32 years) during two phases of the menstrual cycle. Subjects were studied in a randomized order at the same time of day on two separate occasions approximately six weeks apart, once during the follicular phase (days 7 to 10 after menses) and once during the luteal phase (days 7 to 10 after the leutenizing hormone surge) of the menstrual cycle. Black women has higher systolic (P=.01) and diastolic (P=.01) pressures compared with white women. Black women showed greater diastolic pressure (P <.01) and plasma epinephrine (P <.05) responses to stress during the follicular compared with the luteal phase of the menstrual cycle; white women showed no significant changes in these variables. The findings extend the literature on race differences in responsivity to stress and indicate that in contrast to white women, reproductive hormones do influence cardiovascular and catecholamine responsivity to stress in black women.