Marital conflict and endocrine function: are men really more physiologically affected than women?

This study assessed marital conflict behavior and endocrine function in 90 newlywed couples. Blood samples acquired hourly from 8:00 a.m. through 10:00 p.m. were combined to provide composite daytime values for 3 stress hormones -- epinephrine (EPI), norepinephrine (NEPI), and cortisol -- and 3 related hormones (ACTH, growth hormone, and prolactin). These pooled data provided a window on endocrine function in couples for whom the day included a conflict. For wives, higher probabilities of husband's withdrawal in response to wife's negative behavior were associated with higher NEPI and cortisol levels. In addition, higher frequencies of positive behaviors were associated with lower EPI and higher prolactin levels among wives. Husbands' endocrine data were not associated with behavioral data. These findings are discussed in the context of gender models of marital conflict.

Diffusion layer caused by local ionic transmembrane fluxes

Ionic concentrations in the close proximity of a carrier may be different from those in the bulk solution. An immediate layer in the solution in which this situation occurs is known as a diffusion layer. Such diffusion layers were calculated using general diffusion equations and postulating a membrane to be homogeneous in the plane with respect to its permeability. In contrast, the present mathematical model considers single-carrier mediated transport of ions across the membrane and their diffusion away from the carrier site into the electrolyte solution. In particular, the transport of Ca2+ ions is considered. The diffusion of electrolyte ions (Na+ and Cl-) and of Ca2+ ions is described by the Nernst-Planck electrodiffusion equation. The relation between the local electric potential and the ion concentrations is taken into account by the Poisson equation. The equations are solved numerically for radial symmetry by the relaxation method. The model predicts concentration and potential profiles in dependence of the flux rate of Ca2+ ions. It is shown that for fluxes mediated by a single carrier, a diffusion layer becomes significant if the flux is larger than 10(5) Ca2+ ions per second.

Chronic stress down-regulates growth hormone gene expression in peripheral blood mononuclear cells of older adults

"Pituitary" peptides are produced in both endocrine and immune cells. Acute and chronic stress can alter pituitary peptide secretion and might also influence neuroendocrine gene expression in human immune cells. We reasoned that, in Alzheimer caregivers, the chronic stress of caregiving would impact on the sympathetic-adrenal-medullary and hypothalamicpituitary-adrenal axis possibly leading to alterations in GH mRNA in their peripheral blood mononuclear cells (PBMCs). Therefore, we evaluated 10 caregivers and 10 controls subjects using a math and speech stress protocol to determine their neuroendocrine profile and to evaluate any relationship with mononuclear cell GH mRNA levels simultaneously acquired and then evaluated by a quantitative competitive RT-PCR technique. We found a significant (p<.0001) decrease 50% in GH mRNA levels in cells from caregivers. Plasma ACTH and norepinephrine levels were negatively correlated with GH mRNA levels, suggesting their possible role in the down-regulation of mononuclear cell GH gene expression. These observations support the hypothesis that experiences associated with caregiving alter the brain's autonomic nervous system and neuroendocrine control of the hypothalamic-pituitary axis. These and perhaps other influences may then produce altered GH gene expression in mononuclear cells of chronically stressed individuals. It is tempting to speculate that the decreased GH mRNA that we found in these chronically stressed caregivers was partially responsible for their poor response to influenza vaccine and their delayed wound healing.

Psychosocial modulation of cytokine-induced natural killer cell activity in older adults

The objective of this study was to address the cellular and psychological mechanisms underlying previously observed changes in natural killer (NK) cell cytotoxicity associated with chronic stress. We compared 28 current and former spousal caregivers of patients with Alzheimer's disease (AD) and 29 control subjects. NK cells were enriched (E-NK) using a 4-step procedure that resulted in a cell preparation consisting of 88.2% NK cells. These cells were then incubated with either recombinant interferon-gamma (rIFN-gamma) or recombinant interleukin-2 (rIL-2) for 65 hours. Although an average of over 3 years had elapsed since the death of the patient with AD for the former caregivers, current and former caregivers did not differ in the E-NK cell responses to rIFN-gamma and rIL-2. However, the E-NK cell response for the combined caregiver group was significantly suppressed compared with controls, which is consistent with a previous report from our laboratory. Higher E-NK cell responses to each cytokine were associated with heightened levels of positive emotional and tangible social support, independent of levels of depression. Preliminary data suggest that defects of NK cell function in response to rIFN-gamma and rIL-2 as a consequence of caregiver stress may be independent of non-NK cells. Finally, our data are consistent with other studies regarding the role of social support in immune modulation.

Chronic stress alters the immune response to influenza virus vaccine in older adults

To determine whether a chronic stressor (caregiving for a spouse with a progressive dementia) is associated with an impaired immune response to influenza virus vaccination, we compared 32 caregivers' vaccine responses with those of 32 sex-, age-, and socioeconomically matched control subjects. Caregivers showed a poorer antibody response following vaccination relative to control subjects as assessed by two independent methods, ELISA and hemagglutination inhibition. Caregivers also had lower levels of in vitro virus-specific-induced interleukin 2 levels and interleukin 1beta; interleukin 6 did not differ between groups. These data demonstrate that down-regulation of the immune response to influenza virus vaccination is associated with a chronic stressor in the elderly. These results could have implications for vulnerability to infection among older adults.

Marital conflict and endocrine function: are men really more physiologically affected than women?

This study assessed marital conflict behavior and endocrine function in 90 newlywed couples. Blood samples acquired hourly from 8:00 a.m. through 10:00 p.m. were combined to provide composite daytime values for 3 stress hormones -- epinephrine (EPI), norepinephrine (NEPI), and cortisol -- and 3 related hormones (ACTH, growth hormone, and prolactin). These pooled data provided a window on endocrine function in couples for whom the day included a conflict. For wives, higher probabilities of husband's withdrawal in response to wife's negative behavior were associated with higher NEPI and cortisol levels. In addition, higher frequencies of positive behaviors were associated with lower EPI and higher prolactin levels among wives. Husbands' endocrine data were not associated with behavioral data. These findings are discussed in the context of gender models of marital conflict.

Individual differences in cardiac sympathetic control predict endocrine and immune responses to acute psychological stress

Potential mechanisms coordinating individual differences in cardiovascular reactivity and endocrine and immune responses to acute psychological stress were examined. Twenty-three young, healthy women performed a mental arithmetic challenge while measures of cardiovascular, endocrine, and immune function were assessed. Results revealed that the acute stressor was associated with changes in the cardiovascular, endocrine, and immune systems. More important analyses revealed that individual differences in cardiovascular reactivity predicted stress-induced cortisol changes. Furthermore, cardiac sympathetic control, as indexed by preejection period, was specifically related to changes in natural killer cell activity. These results suggest that distinct physiological pathways are activated in response to acute psychological stress.

A symmetric analysis of paired rankings with application to temporal patterns of hormonal concentration

Mallows (1957, Biometrika 44, 114-130) introduced a simple model to describe the distribution of subjects' rankings of the items from some fixed set. Both Feigin (1992, in Probability Models and Statistical Analyses for Ranking Data, 75-91. New York: Springer-Verlag) and Critchlow and Verducci (1992, Journal of the Royal Statistical Society, Series C 41, 17-29) have considered an asymmetric extension of this model, designed to analyze the distribution of subjects' post-treatment rankings, conditional on their pretreatment rankings. Here a symmetric extension is introduced and is used to analyze the joint distribution of paired rankings associated with the patterns of prolactin hormonal response of wife-husband pairs during the course of a marital conflict. Locally most powerful tests are developed to check for independence of the wife and husband responses, and for differences in their divergence from a theoretical pattern of response. Additionally, conditional on the rankings of one group (e.g., the wives), the locally most powerful test of an affinity for the theoretical pattern in the other group (e.g., the husbands) turns out to be closely related to the test given by Critchlow and Verducci.

The reliability and validity of a structured interview for the assessment of infectious illness symptoms

Respiratory infections are the leading cause of morbidity in community populations. We developed a structured interview based on the Health Review (Rose et al., Psychosom. Med. 40: 142-165, 1978) to provide a simple method for periodic assessment of infectious illness, particularly upper respiratory infections. Congruence between interview data and physician diagnoses demonstrated excellent agreement regarding the presence or absence of an infection. Subjects who showed a clinically significant increase in antibody titers to an influenza virus vaccine reported fewer than half as many respiratory infections in the subsequent year as subjects who did not show a significant response. Interrater and test-retest reliabilities were satisfactory. These data support the reliability and validity of this method of assessing infectious illnesses.

Slowing of wound healing by psychological stress

There is evidence that psychological stress adversely affects the immune system. We have investigated the effects of such stress, caused by caring for a relative with Alzheimer's disease, on wound healing. We studied 13 women caring for demented relatives (mean age 62.3 [SE 2.3] years) and 13 controls matched for age (60.4 [2.8] years) and family income. All subjects underwent a 3.5 mm punch biopsy wound. Healing was assessed by photography of the wound and the response to hydrogen peroxide (healing was defined as no foaming). Wound healing took significantly longer in caregivers than in controls (48.7 [2.9] vs 39.3 [3.0] days, p < 0.05). Peripheral-blood leucocytes from caregivers produced significantly less interleukin-1 beta mRNA in response to lipopolysaccharide stimulation than did controls' cells. Stress-related defects in wound repair could have important clinical implications, for instance for recovery from surgery.

Appraisal support predicts age-related differences in cardiovascular function in women

The influence of appraisal support on age-related differences in cardiovascular function was examined. Resting assessments of heart rate, systolic blood pressure (SBP), diastolic blood pressure (DBP), respiratory sinus arrhythmia (RSA), and preejection period were obtained from 45 young and 20 elderly women. Consistent with prior research, results revealed that the elderly women had higher blood pressure and lower RSA than the young women. More important, appraisal support predicted age-related differences in SBP and DBP: Age predicted elevated blood pressure for women low in appraisal support, whereas age was unrelated to blood pressure for women high in appraisal support. These preliminary data suggest that appraisal support may be an important predictor of long-term physiological function and health.

Hormonal modulation of Epstein-Barr virus replication

Among the various factors thought to be associated with the reactivation of latent herpesviruses is psychological stress. An increase in levels of 'stress hormones' such as glucocorticoids occurs in individuals who are stressed and previous studies have shown that glucocorticoid hormones can reactivate latent Epstein-Barr virus (EBV) in vitro. In this study, we confirm that the EBV genome in latently infected lymphoblastoid cells can be reactivated with two glucocorticoid hormones, hydrocortisone and dexamethasone. In addition to hydrocortisone and dexamethasone, we also found that other hormones of the hypothalamic-pituitary-axis (corticotropin-releasing factor and adrenocorticotropin hormone but not epinephrine and norepinephrine) as well as somatostatin can enhance the lytic replication of the HR-1 strain of EBV in superinfected cells. These results suggest that multiple endocrine interactions may be involved in stress-induced reactivation/replication of latent EBV.

Individual differences in cardiac sympathetic control predict endocrine and immune responses to acute psychological stress

Potential mechanisms coordinating individual differences in cardiovascular reactivity and endocrine and immune responses to acute psychological stress were examined. Twenty-three young, healthy women performed a mental arithmetic challenge while measures of cardiovascular, endocrine, and immune function were assessed. Results revealed that the acute stressor was associated with changes in the cardiovascular, endocrine, and immune systems. More important analyses revealed that individual differences in cardiovascular reactivity predicted stress-induced cortisol changes. Furthermore, cardiac sympathetic control, as indexed by preejection period, was specifically related to changes in natural killer cell activity. These results suggest that distinct physiological pathways are activated in response to acute psychological stress.

Temporal relationships and IL-2 dependency of prolactin-induced lymphocyte proliferation

Recombinant preparations of human prolactin (hPRL) and interleukin 2 (hIL-2) as well as monoclonal antibodies to these growth factors were used to study the synergistic interaction of PRL and IL-2 in Nb2 rat lymphoma lactogen-dependent cells. It was shown that IL-2 stimulated Nb2 cell proliferation in lactogen-free culture medium. Experiments with short-term exposure to growth factor demonstrated that PRL was required only during the initial 12 h of incubation while IL-2 was mitogenic regardless of the time it was added. Antibody to IL-2 partially inhibited both PRL- and IL-2-induced proliferation whereas antibody to PRL significantly decreased PRL but not IL-2-induced proliferation. These findings suggest that the complete mitogenic effect of PRL on Nb2 cells requires stimulation of IL-2 production.

Psychoneuroimmunology and health consequences: data and shared mechanisms

There is evidence linking psychosocially mediated immunological alterations with cancer, infectious illness, and HIV progression. The data reviewed suggest that immune modulation by psychosocial stressors and/or interventions may importantly influence health status. The research literature also suggests that the impact of chronic stressors and psychosocial factors on sympathetic nervous system and endocrine function influences the immune system, thereby providing shared mechanisms that may impact on disease susceptibility and progression across a broad spectrum of disorders. A better understanding of individual vulnerability, such as occurs with aging, may help to pinpoint those at greatest risk.

Heterogeneity in neuroendocrine and immune responses to brief psychological stressors as a function of autonomic cardiac activation

Human responses to brief psychological stressors are characterized by changes and large individual differences in autonomic, neuroendocrine, and immune function. The authors examined the effects of brief psychological stressors on cardiovascular, neuroendocrine, and cellular immune response in 22 older women to investigate the common effects of stress across systems. They also used interindividual variation in heart rate reactivity, cardiac sympathetic reactivity (as indexed by preejection period reactivity in their reactivity paradigm), and cardiac vagal reactivity (as indexed by respiratory sinus arrhythmia reactivity) to explore the heterogeneity in human responses to brief psychological stressors. The results revealed that brief psychological stressors heightened cardiac activation, elevated plasma catecholamine concentrations, and affected the cellular immune response. It was also found that individuals characterized by high, relative to low, cardiac sympathetic reactivity showed higher stress-related changes in adrenocorticotropic hormone and cortisol plasma levels but comparable changes in epinephrine and norepinephrine concentrations. These data suggest that the effects of psychological stressors on cardiovascular and cellular immune response are governed by coordinated regulatory mechanism(s) and that going beyond the simple notion of heart rate reactivity to examine neural substrates may shed light on the interrelationships among and the regulatory mechanisms for the autonomic, endocrine, and immune responses to stressors.

Influence of academic stress and season on 24-hour mean concentrations of ACTH, cortisol, and beta-endorphin

We investigated the influence of a common stressful event, i.e., academic examinations, on the 24-h mean concentration of adrenocorticotropic hormone (ACTH), cortisol, and/or beta-endorphin. In addition, we evaluated the effect of season on the endocrine response to this stressor. We studied medical students (n = 55), screened for a variety of health and life style factors, from three consecutive medical school classes 1 month before, during, and 2 weeks following examinations. Hourly blood samples were obtained from an indwelling catheter and two serum pools were made (0800-2200h = day and 2300-0700h = night). Examinations produced a significant (p < .001) increase in perceived stress scores. In addition, we found a significant (p < .001) effect of examination stress on the increase in mean daytime but not nocturnal ACTH levels during autumn, but not during the spring. In contrast, the examination stress did not significantly affect day or night mean cortisol levels from baseline to examination week. We further divided the students by whether their perceived stress scores increased during examination week and fell during recovery (Group 1) or whether their perceived stress scores did not follow the expected pattern (Group 2). We found that in the Group 1 students who perceived the most stress, cortisol levels significantly increased (p < .001) from baseline to examination. Therefore, the nature of the stressor and the state of the responder were of equal importance in the observed cortisol response during examinations among these students. Further, academic stress had no significant effect on beta-endorphin levels. Finally, we found that the mean day and night ACTH levels were higher (p < .001) in the spring than in the fall; a seasonal influence on cortisol and beta-endorphin concentrations, however, was not observed. In summary, we have demonstrated that stress associated with the taking of examinations produces a dissociation among mean 24-h levels of ACTH, cortisol, and beta-endorphin. In addition, daytime cortisol levels increased during examinations only in the group of students whose perceived stress scores increased. Further, a seasonal influence on ACTH secretion was suggested by these results with higher levels observed in the spring than in the fall.

Chronic stress, social support, and persistent alterations in the natural killer cell response to cytokines in older adults

To address the long-term physiological consequences of chronic stressors, 14 continuing or current family caregivers of Alzheimer's disease (AD) patients, 17 former AD caregivers, and 31 control subjects were compared. Continuing and former caregivers did not differ on depressive symptomatology or perceived stress; both groups were significantly more depressed and stressed than controls. Furthermore, continuing and former caregivers did not differ in the response of NK cells in vitro to recombinant interferon-gamma and recombinant interleukin-2, and both groups had a significantly poorer response to these cytokines than controls. The physiological and psychological consequences of chronic stressors may persist well beyond the cessation of the actual stressor.

A biobehavioral model of cancer stress and disease course

Approximately 1 million Americans are diagnosed with cancer each year and must cope with the disease and treatments. Many studies have documented the deteriorations in quality of life that occur. These data suggest that the adjustment process is burdensome and lengthy. There is ample evidence showing that adults experiencing other long-term stressors experience not only high rates of adjustment difficulties (e.g., syndromal depression) but important biologic effects, such as persistent downregulation of elements of the immune system, and adverse health outcomes, such as higher rates of respiratory tract infections. Thus, deteriorations in quality of life with cancer are underscored if they have implications for biological processes, such as the immune system, relating to disease progression and spread. Considering these and other data, a biobehavioral model of adjustment to the stresses of cancer is offered, and mechanisms by which psychological and behavioral responses may influence biological processes and, perhaps, health outcomes are proposed. Finally, strategies for testing the model via experiments testing psychological interventions are offered.

A biobehavioral model of cancer stress and disease course

Approximately 1 million Americans are diagnosed with cancer each year and must cope with the disease and treatments. Many studies have documented the deteriorations in quality of life that occur. These data suggest that the adjustment process is burdensome and lengthy. There is ample evidence showing that adults experiencing other long-term stressors experience not only high rates of adjustment difficulties (e.g., syndromal depression) but important biologic effects, such as persistent downregulation of elements of the immune system, and adverse health outcomes, such as higher rates of respiratory tract infections. Thus, deteriorations in quality of life with cancer are underscored if they have implications for biological processes, such as the immune system, relating to disease progression and spread. Considering these and other data, a biobehavioral model of adjustment to the stresses of cancer is offered, and mechanisms by which psychological and behavioral responses may influence biological processes and, perhaps, health outcomes are proposed. Finally, strategies for testing the model via experiments testing psychological interventions are offered.

Characterization of neutralizing monoclonal antibodies directed against Staphylococcus aureus alpha-toxin

A panel of neutralizing murine monoclonal antibodies (MAbs) against Staphylococcus aureus alpha-toxin has been established, using formaline-inactivated alpha-toxin as an immunogen. Five independent groups of neutralizing epitopes have been identified representing five functionally important structures in the toxin molecule. Because none of the antibodies binds to overlapping decapeptides representing the toxin sequence or to bromocyanogen cleavage products of alpha-toxin, they may all bind to conformational epitopes. Nevertheless, they all bind to monomeric alpha-toxin in a Western blot. Three of the antibodies bind to the toxin monomer in an enzyme-linked immunosorbent assay (ELISA) in the presence, but not in the absence, of detergent. These epitopes are not accessible in hexameric toxin; two of them may represent the contact sites of the toxin monomers upon hexamerization and one is related to a structurally important glycine-rich central hinge region. Two different antibodies bind to monomeric toxin in an ELISA in the presence and absence of detergent and their epitopes are present more than once on oligomeric toxin; they bind strongly to hexameric toxin in a Western blot. The binding properties of the antibodies to alpha-toxin in different assay systems are summarized in an epitope model, which describes the presence of neutralizing domains in the different conformational steps required for pore formation.

Chronic stress, social support, and persistent alterations in the natural killer cell response to cytokines in older adults

To address the long-term physiological consequences of chronic stressors, 14 continuing or current family caregivers of Alzheimer's disease (AD) patients, 17 former AD caregivers, and 31 control subjects were compared. Continuing and former caregivers did not differ on depressive symptomatology or perceived stress; both groups were significantly more depressed and stressed than controls. Furthermore, continuing and former caregivers did not differ in the response of NK cells in vitro to recombinant interferon-gamma and recombinant interleukin-2, and both groups had a significantly poorer response to these cytokines than controls. The physiological and psychological consequences of chronic stressors may persist well beyond the cessation of the actual stressor.

The effects of an acute psychological stressor on cardiovascular, endocrine, and cellular immune response: a prospective study of individuals high and low in heart rate reactivity

High and low reactors were preselected on the basis of their heart rate reactivity to a speech stressor in a prescreening session. In the main study, subjects were exposed to a mental arithmetic plus noise stressor. Cardiovascular activity was recorded during baseline and stressor, and blood was drawn prior to and following the stressor for endocrine and immune assays. Results revealed that the stressor decreased the blastogenic response to concanavalin A and increased natural killer cell numbers and cytotoxicity, absolute numbers of CD8+ T-lymphocytes, norepinephrine and epinephrine levels, heart rate, and blood pressure responses. In addition, cortisol and natural killer cell cytotoxicity responses to the stressor differentiated individuals high versus low in heart rate reactivity. These results suggest that the interactions among the autonomic nervous system, endocrine system, and immune system are not only amenable to psychophysiological analysis but that such analyses may play an important role in illuminating underlying mechanisms.