Physiological and subjective stress responses in surgical patients

Autonomic responses, mood and psychological coping were assessed in two groups of orthopaedic patients during hospitalisation for major or minor surgery. Eight patients admitted for total hip replacement and seven patients undergoing knee arthroscopy were seen daily for two days before surgery until discharged from hospital. Mood and coping questionnaires were administered on each session, while pain, heart rate, blood pressure, skin conductance level, palmar sweat prints and forearm EMG were also recorded. Heart rate increased from pre- to post-operative assessments, while skin conductance and palmar sweating fell to low levels on the days immediately following surgery, returning to basal values only after several days. Self ratings of anxiety, fatigue, depression and pain were highest on the immediate post-operative days. Patients utilised the coping factors Rational Cognition and Behavioural Action to the greatest extent, but ratings on coping factors fluctuated little over the study period. The interrelations between these measures and possible explanations of the results are discussed.     

Work stress, socioeconomic status and neuroendocrine activation over the working day

Socioeconomic status (SES) differences in cardiovascular and metabolic disease risk may be mediated in part by differential activation of neuroendocrine pathways. We have previously found that salivary cortisol levels over the working day are greater in lower than higher SES men, but that cortisol output is greater in higher than lower SES women. This study investigated the role of work stress in generating these patterns, analysing cortisol output in relation to job demands and job control. Participants were 97 men and 84 woman from the Whitehall II cohort, London, UK, recruited from higher and lower grades of employment. Saliva samples were obtained on waking and 30 min later to assess the cortisol waking responses, and at two hourly intervals over a typical working day. Cortisol responses to waking were positively associated with high job demands, but this effect was attenuated by higher SES. In women but not men, cortisol levels over the remainder of the day were elevated in lower SES participants who experienced high job demands, but depressed in lower status women who reported low job demands. Job control did not influence cortisol responses to waking, but in men cortisol levels over the remainder of the day were inversely related to job control. These cortisol differences were independent of age, smoking status and time of waking up. Subjectively, the most stress was reported by higher SES individuals who experienced low job control. We conclude that work stress and SES are related differently to cortisol responses to waking and cortisol output over the day. Job control may partly mediate SES differences in cortisol in men, while job demands are more relevant for women. Analyses of psychobiological pathways must take account of variations in exposure to chronic stressors as well as differences in responsivity to stressors.     

Delaying orthostatic syncope with mental challenge: a pilot study

At orthostatic vasovagal syncope there appears to be a sudden decline of sympathetic activity. As mental challenge activates the sympathetic system, we hypothesized that doing mental arithmetic in volunteers driven to the end point of their cardiovascular stability may delay the onset of orthostatic syncope. We investigated this in healthy male subjects. Each subject underwent a head up tilt (HUT)+ graded lower body negative pressure (LBNP) up to presyncope session (control) to determine the orthostatic tolerance time, OTT (Time from HUT commencement to development of presyncopal symptoms/signs). Once the tolerance time was known, a randomized crossover protocol was used: either 1) Repeat HUT+LBNP to ensure reproducibility of repeated run or 2) HUT+LBNP run but with added mental challenge (2 min before the expected presyncope time). Test protocols were separated by 2 weeks. Our studies on five male test subjects indicate that mental challenge improves orthostatic tolerance significantly. Additional mental loading could be a useful countermeasure to alleviate the orthostatic responses of persons, particularly in those with histories of dizziness on standing up, or to alleviate hypotension that frequently occurs during hemodialysis or on return to earth from the spaceflight environment of microgravity.     

Decreased reaction time variability is associated with greater cardiovascular responses to acute stress

Cardiovascular (CV) responses to mental stress are prospectively associated with poor CV outcomes. The association between CV responses to mental stress and reaction times (RTs) in aging individuals may be important but warrants further investigation. The present study assessed RTs to examine associations with CV responses to mental stress in healthy, older individuals using robust regression techniques. Participants were 262 men and women (mean age = 63.3 ± 5.5 years) from the Whitehall II cohort who completed a RT task (Stroop) and underwent acute mental stress (mirror tracing) to elicit CV responses. Blood pressure, heart rate, and heart rate variability were measured at baseline, during acute stress, and through a 75‐min recovery. RT measures were generated from an ex‐Gaussian distribution that yielded three predictors: mu‐RT, sigma‐RT, and tau‐RT, the mean, standard deviation, and mean of the exponential component of the normal distribution, respectively. Decreased intraindividual RT variability was marginally associated with greater systolic (B = ?.009, SE = .005, p = .09) and diastolic (B = ?.004, SE = .002, p = .08) blood pressure reactivity. Decreased intraindividual RT variability was associated with impaired systolic blood pressure recovery (B = ?.007, SE = .003, p = .03) and impaired vagal tone (B = ?.0047, SE = .0024, p = .045). Study findings offer tentative support for an association between RTs and CV responses. Despite small effect sizes and associations not consistent across predictors, these data may point to a link between intrinsic neuronal plasticity and CV responses.     

Steady‐state antigen‐expressing dendritic cells terminate CD4+ memory T‐cell responses

CD4⁺ T cells are important effectors of inflammation and tissue destruction in many diseases of immune dysregulation. As memory T cells develop early during the preclinical stages of autoimmune and inflammatory diseases, immunotherapeutic approaches to treatment of these diseases, once established, must include the means to terminate memory T‐cell responses. Traditionally, it has been considered that, due to their terminally differentiated nature, memory T cells are resistant to tolerance induction, although emerging evidence indicates that some immunotherapeutic approaches can terminate memory T‐cell responses. Here, we demonstrate that CD4⁺ memory T‐cell responses can be terminated when cognate antigen is transgenically expressed in steady‐state DC. Transfer of in‐vitro‐generated CD4⁺ memory T cells establishes, in nontransgenic recipients, a stable and readily recalled memory response to cognate antigen. In contrast, upon transfer to mice expressing cognate antigen targeted to DC, memory CD4⁺ T cells undergo a phase of limited proliferation followed by substantial deletion, and recall responses are effectively silenced. This finding is important in understanding how to effectively apply immunotherapy to ongoing T‐cell‐mediated autoimmune and inflammatory diseases.     

Lack of association between depressive symptoms and markers of immune and vascular inflammation in middle-aged men and women

BACKGROUND: Disturbed immune activity and vascular inflammation are associated both with clinical depression and coronary atherogenesis, and may constitute a mechanism through which depression contributes to coronary heart disease. If this is the case, then non-clinical depressive symptoms and psychological distress should be associated with immune activation and vascular inflammation. We tested this hypothesis in a healthy middle-aged sample. METHOD: Measures of depressive symptoms and hopelessness were obtained from 226 volunteers (122 men, 104 women) aged 47-59 years, drawn from the Whitehall II epidemiological cohort. C-reactive protein, fibrinogen, plasma interleukin-6, tumour necrosis factor alpha, interleukin-1 receptor antagonist, and T- and B-lymphocyte, and natural killer cells numbers and percentages were assessed. RESULTS: There were no associations between measures of depressive symptoms or hopelessness and markers of immune activation or inflammatory response. CONCLUSIONS: Factors such as the measures of depressive symptoms, the choice of inflammatory and immune indices, and sample size, are unlikely to be responsible for these null effects. Associations may be confined to clinically depressed or older age populations, but there are problems of confounding by co-morbidity and health compromising behaviours in this literature. We conclude that disturbances of immune function and inflammatory processes are unlikely to be primarily responsible for the associations between depressive symptoms and coronary heart disease described in the literature, and that other pathways are involved.     

The effects of chronic tea intake on platelet activation and inflammation: a double-blind placebo controlled trial

BACKGROUND: Tea drinking appears to protect against the development of coronary heart disease (CHD), but the mediating pathways are uncertain. We studied the effects of 6 weeks of black tea or placebo on platelet activation, C-reactive protein (CRP), total antioxidant status, and soluble (s) P-Selectin in a randomized double-blind trial. METHODS: Healthy non-smoking men aged 18-55 years were randomized to black tea (N=37) or placebo (N=38) following a 4-week washout period during which they drank no tea, coffee or caffeinated beverages, but consumed caffeinated placebo tea. Bloods were drawn after 6 weeks of treatment. Platelet activation was assessed by measuring leukocyte-platelet aggregates using whole blood flow cytometry. RESULTS: Following treatment, the tea group had fewer monocyte-platelet aggregates (means 5.84 versus 6.60%, P=0.027), neutrophil-platelet aggregates (P=0.017), total leukocyte-platelet aggregates (P=0.027), and lower plasma C-reactive protein (means 0.76 versus 0.97 mg/L, P=0.05) than the placebo group. There were no differences in total antioxidant status or soluble P-Selectin. CONCLUSIONS: Chronic tea consumption reduces platelet activation and plasma C-reactive protein in healthy men. Effects cannot be attributed to observer bias or lifestyle confounders. These effects of tea may contribute to sustained cardiovascular health.     

Psychosocial and clinical factors predicting resumption of work following acute myocardial infarction in Japanese men

We investigated psychosocial and clinical factors related to work resumption, delay in returning to work and level of work activity after an acute myocardial infarction in Japanese male patients. A total of 111 married male patients experiencing a first acute myocardial infarction, aged less than 66 years and in full-time employment participated. Interviews and questionnaires were administered during hospitalization to assess potential predictors of work-related outcomes, with follow-up (81.6%) after an average of 8 months. We found that failure to return to work was predicated independently by older age (P=0.019), an introverted personality (P=0.011) and the presence of depressive symptoms during hospitalization (P=0.031). Delay in returning to work was predicted by greater concerns about health (P=0.011), low social support (P=0.021), and a failure to recognise a link between stress, coping style and illness (P=0.001). Resuming work at a lower activity level than before infarction was associated with older age (P=0.008), higher health concerns (P=0.012), and patients' predictions of their lower work activity (P=0.001). Clinical indices of infarction size and disease severity did not predict work-related outcomes. We conclude that psychosocial factors are associated with work resumption in Japanese men characterised by a job-centred lifestyle, with different factors being important for different work outcomes. The psychosocial factors found to be important are similar to those identified in Western societies.