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Christopher Ring

Publications and source records attributed to Christopher Ring.

At least 37 records · Page 2Linked to original sources
PubMed2004

Mental stress-induced hemoconcentration: Sex differences and mechanisms.

Given the possible role of hemoconcentration in myocardial infarction and apparent sex differences in susceptibility, three studies examined sex differences in mental stress-induced hemoconcentration, and explored possible underlying mechanisms. Blood pressure, heart rate, and hematocrit were monitored at rest and in response to a mental stress task that was contrived to be increasingly provocative across the three studies. This was confirmed by self-report, performance, and cardiovascular reactivity data. The most convincing evidence for hemoconcentration effects and sex differences in hemoconcentration emerged from exposure to the more provocative of the stress tasks, with men also showing greater hemoconcentration than women. Blood pressure reactivity was a strong and consistent predictor of stress-induced hemoconcentration. These findings may help to explain sex differences in susceptibility to myocardial infarction.

Adult↗
PubMed2004

Effects of arousal and natural baroreceptor activation on the human muscle stretch reflex.

The nociceptive flexion reflex is inhibited during systole; this inhibition may be due to increased baroreceptor stimulation. It is yet to be determined whether other spinal reflexes are similarly modulated across the cardiac cycle. There is also evidence that stretch and tendon reflexes are facilitated by increased arousal. This study investigated the effects of phase of the cardiac cycle and arousal on the muscle stretch reflex components M1, M2, and M3. Stretch reflexes were elicited in leg muscles at six intervals across the cardiac cycle during rest, number repetition, and mental arithmetic. Mental arithmetic provoked increased cardiovascular arousal and facilitated both M1 and M2 compared to rest and number repetition. The stretch reflex did not vary with the phase of the cardiac cycle. While the stretch reflex is susceptible to arousal, natural baroreceptor-mediated modulation across the cardiac cycle may be specific to nociception.

Adult↗
PubMed2003

Antibody response to vaccination and psychosocial stress in humans: relationships and mechanisms.

The purpose of this review is to determine the effects of psychosocial stress on antibody response to vaccination in humans, consider possible mechanisms, and identify agenda for future research. Studies of the association between stress and vaccination response in humans were reviewed. There is evidence of a negative association between stress and antibody response to vaccination, which is most apparent with thymus-dependent vaccines and when measured at extended times after vaccination. Preliminary findings implicate the hypothalamic-pituitary-adrenal axis and sympathetic nervous system as potential mechanisms, although a role for unhealthy behaviours cannot be discounted at this stage. Results to date are sufficiently indicative to direct future research to untangling their theoretical ramifications, as well as realising their clinical implications.

Antibody Formation↗
PubMed2003

Life events, perceived stress and antibody response to influenza vaccination in young, healthy adults.

OBJECTIVES: Chronic stress has been associated with impaired response to influenza vaccination in the elderly. This study investigated whether mild, intermittent stress experienced by young, healthy adults has a similar effect. METHODS: Antibody and psychological status were determined prevaccination and 5 weeks and 5 months later; a fourfold increase in antibody to at least one viral strain was considered protective. RESULTS: At 5 months, unprotected participants reported significantly more life events and tended to report more perceived stress than those who were protected. CONCLUSIONS: Psychological stress is detrimental to long-term maintenance of antibody levels following vaccination in young, healthy adults.

Adolescent↗
PubMed2003

Effects of artificial and natural baroreceptor stimulation on nociceptive responding and pain.

The arterial baroreflex may mediate hypertensive hypoalgesia. Carotid baroreceptors can be artificially stimulated by neck suction and inhibited by compression. Effects of brief neck suction and compression on nociceptive responding and pain were studied in 25 normotensive adults. The sural nerve was electrocutaneously stimulated at threshold intensity during systole or diastole combined with neck suction, neck compression, or no pressure. Nociceptive responding was indexed by electromyographic activity elicited in the biceps femoris. Participants rated the intensity of sural stimulation. Although artificial baroreceptor stimulation (suction) did not affect nociceptive responding, baroreceptor inhibition (compression) reduced pain ratings. In contrast, natural baroreceptor stimulation during systole reduced nociceptive responding compared to diastole, but did not affect pain ratings. The data provide partial support for baroreflex modulation of pain.

Adult↗
PubMed2002

Secretory immunoglobulin A reactions to prolonged mental arithmetic stress: inter-session and intra-session reliability.

Although previous evidence suggests that mucosal immunity may be influenced by mental stress, the importance of the duration of stress exposure on secretory immunoglobulin A (sIgA) has yet to be fully elucidated. Salivary sIgA and cardiovascular activity were measured at rest, following 14 and 28 min of mental arithmetic, and after recovery in 24 men and women on two sessions 2-4 days apart. Mental arithmetic was, on both sessions and after both the early and late phases of the task, associated with increases in sIgA concentration and sIgA secretion rate compared to rest and recovery. Task levels of sIgA concentration and sIgA secretion rate showed moderate to high intra- and inter-session test-retest reliability, while test-retest reliability was lower for change scores. Blood pressure and pulse rate were also elevated by the mental stress task, although correlational analyses revealed that stress-induced changes in sIgA were not related to cardiovascular reactions.

Adolescent↗
PubMed2002

Catastrophizing is related to pain ratings, but not nociceptive flexion reflex threshold.

Catastrophizing is reliably associated with increased reports of clinical and experimental pain. To test the hypothesis that catastrophizing may heighten pain experience by increasing nociceptive transmission through spinal gating mechanisms, the present study examined catastrophizing as a predictor of pain ratings and nociceptive flexion reflex (NFR) thresholds in 88 young adult men (n=47) and women (n=41). The NFR threshold was defined as the intensity of electrocutaneous sural nerve stimulation required to elicit a withdrawal response from the biceps femoris muscle of the ipsilateral leg. Participants completed an assessment of their NFR threshold and then provided pain ratings using both a numerical rating scale (NRS) and the short-form McGill pain questionnaire (SF-MPQ). Pain catastrophizing was assessed using the catastrophizing subscale of the coping strategies questionnaire (CSQ). Although catastrophizing was positively related to both NRS and SF-MPQ pain ratings, catastrophizing was not significantly related to NFR threshold. These findings suggest that differential modulation of spinal nociceptive input may not account for the relationship between catastrophizing and increased pain.

Adaptation, Psychological↗
PubMed2002

Guidelines for mechanical lung function measurements in psychophysiology.

Studies in psychophysiology and behavioral medicine have uncovered associations among psychological processes, behavior, and lung function. However, methodological issues specific to the measurement of mechanical lung function have rarely been discussed. This report presents an overview of the physiology, techniques, and experimental methods of mechanical lung function measurements relevant to this research context. Techniques to measure lung volumes, airflow, airway resistance, respiratory resistance, and airflow perception are introduced and discussed. Confounding factors such as ventilation, medication, environmental factors, physical activity, and instructional and experimenter effects are outlined, and issues specific to children and clinical groups are discussed. Recommendations are presented to increase the degree of standardization in the research application and publication of mechanical lung function measurements in psychophysiology.

Airway Resistance↗
PubMed2002

Shifting hemodynamics of blood pressure control during prolonged mental stress.

The present study examined the hemodynamics underlying blood pressure elevations for evidence of a shift in the control of blood pressure during prolonged mental stress. Mean arterial pressure (MAP), cardiac output (CO), and total peripheral resistance (TPR) were measured at rest, during a 28-min mental arithmetic stress task, and during recovery, in 30 young healthy men and women. The stress task elicited a sustained increase in MAP: CO rose during the first half of the task but returned to baseline levels during the last quarter of the task, whereas TPR increased as the task progressed. When participants' hemodynamic reactions were classified as cardiac, vascular, or neither, there were more cardiac reactors early relative to late in the task, whereas there were more vascular reactors late relative to early. Thus, the sustained pressor response was initially supported mainly by cardiac mechanisms but subsequently by predominantly vascular mechanisms.

Adult↗
PubMed2002

The human nociceptive flexion reflex threshold is higher during systole than diastole.

A baroreflex mechanism may explain hypertensive hypoalgesia. At rest, arterial baroreceptors are stimulated during the systolic upstroke of the pressure pulse wave. This study examined the effects of naturally occurring variations in baroreceptor activity during the cardiac cycle on an objective measure of pain, the nociceptive flexion reflex (NFR). Two interleaved up-down staircase procedures determined separate NFR thresholds during systole and diastole in 36 healthy, normotensive young adults. On odd-numbered trials, the sural nerve was stimulated electrocutaneously at R + 300 ms whereas on even-numbered trials, stimulation was delivered at R + 600 ms. The NFR threshold was higher at R + 300 ms than R + 600 ms. In contrast, stimulus intensity ratings did not differ between R + 300 ms and R + 600 ms. Stimulation of baroreceptors by natural increases in blood pressure during the systolic phase of the cardiac cycle was associated with dampened nociception.

Adult↗
PubMed2002

Cortisol and cardiovascular reactions to mental stress and antibody status following hepatitis B vaccination: a preliminary study.

This study examined possible neuroendocrine mechanisms underlying the association between stress and antibody response to vaccination. Hepatitis B antibody titers were obtained, and salivary cortisol and cardiovascular activity measured during baseline, mental arithmetic, and recovery in 30 undergraduates. It was hypothesised that higher reactivity would be associated with poorer antibody status. Compared to individuals with high antibody titers, those with low titers had significantly lower cortisol levels throughout, exhibited a significantly attenuated end-of-task reduction in cortisol relative to resting baseline, and had larger cardiac output and inotropic reactions, but smaller increases in total peripheral resistance, to mental arithmetic. In sum, variations in indices of both hypothalamic pituitary adrenocortical axis and sympathetic nervous system activity were associated with individual differences in immune response to vaccination.

Adult↗
PubMed2002

Cellular and mucosal immune reactions to mental and cold stress: associations with gender and cardiovascular reactivity.

To examine gender differences in immune reactions to stress and relationships between immune and cardiovascular reactivity, measures of cellular and mucosal immunity and cardiovascular activity were recorded in 77 men and 78 women at rest and in response to active (mental arithmetic) and passive (cold pressor) stress tasks. Both tasks reduced CD4+ T cells and the CD4/8 ratio. Total lymphocytes, NK cells, CD8+ T cells, and secretory immunoglobulin A (sIgA) increased with active stress. Passive stress decreased sIgA. At rest, men had more NK cells, less CD4+ T cells, and fewer neutrophils than women. Mental stress increased sIgA in men but not women. Cardiovascular reactivity to active stress was associated with increases in NK cells. The data support the hypothesis that stress-related increases in lymphocytes are beta-adrenergically mediated, and suggest that the fall in CD4+ T cells may be alpha-adrenergically driven. Mechanisms underlying sIgA reactions are more difficult to determine. Men and women differed in some cell counts, but not in reactivity, although gender influenced sIgA reactions to arithmetic.

Adult↗
PubMed2002

In-hospital symptoms of depression do not predict mortality 3 years after myocardial infarction.

BACKGROUND: The main aim of this study was to examine the relationship between symptoms of depression following myocardial infarction (MI) and 3-year survival status. METHODS: The Beck Depression Inventory was completed by 288 patients hospitalized for MI. Patients' cardiological status, including indices of disease severity, were recorded or derived from hospital notes. Three-year survival status was determined using patient information systems and cause of death ascertained from death certificates. RESULTS: During the 3 years of follow-up, 38 patients (13%) died, 33 (11%) from cardiac causes. Symptoms of depression did not predict either cardiac-specific or all-cause mortality. Similarly, in-hospital levels of anxiety were not associated with prognosis. In contrast, measures of disease severity and discharge medication status were strong prognostic indicators. Depression was not related to measures of disease severity at entry to the study. CONCLUSIONS: Symptoms of depression following MI do not predict longer-term survival, although measures of disease severity and discharge medication status do. Previous positive results for depression and cardiac mortality in MI patients could reflect the occasional confounding of depression with disease severity.

Aged↗
PubMed2002

Competitiveness and hemodynamic reactions to competition.

This study examines the effects of competition and competitiveness on hemodynamics. Cardiovascular activity was measured in 27 men at resting baseline and during a car racing game, which comprised a solo race against time and three races against an experimenter. To assess hematocrit, blood was collected at rest and after the final race. Trait competitiveness was assessed by questionnaire. Competition elicited increases in hematocrit, blood pressure, heart rate, and total peripheral resistance, as well as decreases in preejection period and heart rate variability. The final race was rated as more competitive than the solo race. Compared to intrapersonal solo racing, the final interpersonal race was associated with shorter preejection periods and faster heart rates, markers of beta-adrenergic activation. Although trait competitiveness was not associated with beta-adrenergic activation, variations in state competitiveness were.

Adolescent↗
PubMed2002

The prevalence and persistence of depression and anxiety following myocardial infarction.

OBJECTIVES: This study was designed to assess the prevalence and persistence of symptoms of depression and anxiety during the first 12 months following acute myocardial infarction (MI). DESIGN AND METHODS: In a prospective study, 288 MI patients were assessed for symptoms of depression and anxiety using the Beck Depression Inventory (BDI) and the State-Trait Anxiety Inventory (STAI) in hospital, 2-15 days following MI, and 4 and 12 months subsequently. RESULTS: During hospitalization, 89 (30.9%) and 75 (26.1%) patients registered elevated BDI scores (>/=10) and state anxiety scores (>/=40), respectively. The 4 and 12 month prevalence rates were 37.7% and 37.2% for depressive symptoms, and 41.8% and 40.0% for anxious symptoms, respectively. Depression and anxiety were highly co-morbid, with 51% of patients experiencing significant levels of depressive and anxious symptoms at baseline. More than half the patients with complete BDI and state anxiety data experienced either elevated symptoms of anxiety or depression throughout the first year following MI. CONCLUSIONS: Symptoms of depression and anxiety are prevalent, persistent problems during the first year following MI. This study highlights the importance of routine psychological assessment for MI patients both in hospital and after discharge.

Journal Article↗
PubMedDate not supplied

Stress, coping, and hepatitis B antibody status.

OBJECTIVE: The present study investigated the association between exposure to stressful life events, coping style, and antibody status after hepatitis B vaccination. METHODS: Two hundred sixty medical school undergraduates, who had received the three-dose hepatitis B vaccine before recruitment to this study, completed questionnaires measuring exposure to stressful life events during the past year, customary coping strategies, and health behaviors. Antibodies against hepatitis B surface antigen were determined; levels <100 mIU/ml were deemed inadequate. RESULTS: Two participant cohorts were identified: those vaccinated within the last year and those vaccinated earlier. In the early vaccination cohort, participants with greater-than-average stress exposures had a more than two-fold increased risk of having an inadequate antibody titer. Coping by accepting the reality of stressful situations proved protective, whereas coping by substance use increased the risk of having an inadequate antibody count in this cohort. These associations remained significant after adjustment for possible mediators. Furthermore, the effects of stress and coping were largely independent of one another. Neither stress nor coping was significantly associated with antibody status in the recently vaccinated cohort. CONCLUSIONS: The present study confirms that the immune system is sensitive to variations in psychological factors. Stressful life events and coping strategy seem to have a continuing impact on hepatitis B antibody status.

Adaptation, Psychological↗
PubMedDate not supplied

Perceived stress and psychological well-being are associated with antibody status after meningitis C conjugate vaccination.

OBJECTIVE: Psychological stress has been associated with reduced immune response to a variety of vaccinations. This study is the first to examine antibody status after vaccination with a conjugate vaccine, in which a polysaccharide antigen is conjugated to a protein to elicit a thymus-dependent antibody response. METHODS: Sixty undergraduate students, who had received the meningitis C conjugate vaccine before recruitment, attended a single testing session. They provided a blood sample and completed a battery of questionnaires, including the Life Events Scale for Students, Perceived Stress Scale, and General Health Questionnaire (GHQ-28). Both meningitis C-specific antibody titer and the serum bactericidal assay titer to whole meningitis C bacteria were assayed. RESULTS: High perceived stress, but not life events stress, was associated with low antibody titers. Poor antibody titers were also predicted by relatively low levels of psychological well-being as measured by the GHQ-28. Of the GHQ-28 subscales, anxiety/insomnia and social dysfunction were associated with antibody status. No psychological variables emerged from bivariate analyses as predictive of the adequacy of bactericidal titer. CONCLUSIONS: This study provides the first evidence that antibody status after a conjugate vaccination may be susceptible to psychological influences.

Adaptation, Psychological↗