Sex differences in sympathetic-adrenal medullary reactions induced by different stressors

Disrupted Circadian Rhythm of Epinephrine in Males With Youth-Onset Type 2 Diabetes

Context

Blood pressure and plasma catecholamines normally decline during sleep and rapidly increase in early morning. This is blunted in adults with type 2 diabetes (T2D).

Objective

We hypothesize that increased sympatho-adrenal activity during sleep differentiates youth with T2D from nondiabetic obese youth and lean youth.

Methods

Fasting spot morning and 24-hour urines were collected in obese adolescents with and without T2D, and normal-weight controls. Fractionated free urine catecholamines (epinephrine, norepinephrine, and dopamine) were measured, and the ratio of fasting spot morning to 24-hour catecholamines was calculated.

Results

Urinary 24-hour catecholamine levels were comparable across the 3 groups. Fasting morning epinephrine and the ratio of fasting morning/24-hour epinephrine were higher in youth with T2D (P = 0.004 and P = 0.035, respectively). In males, the ratio of fasting morning/24-hour epinephrine was also higher in youth with T2D (P = 0.005). In females, fasting morning norepinephrine and the ratio of fasting morning/24-hour dopamine were lower in obese youth with and without T2D (P = 0.013 and P = 0.005, respectively) compared with lean youth. Systolic blood pressure was higher in diabetic participants than other groups; males trended higher than females.

Conclusion

Circadian rhythm in catecholamines is disrupted in youth-onset T2D, with a blunted overnight fall in urinary epinephrine in males. Conversely, fasting morning norepinephrine and dopamine levels were lower in obese females with or without T2D. Higher nocturnal catecholamines in males with T2D might associate with, or predispose to, hypertension and cardiovascular complications. Lower catecholamine excretion in females with obesity might serve an adaptive, protective role.

Catecholamines Are the Key Trigger of COVID-19 mRNA Vaccine-Induced Myocarditis: A Compelling Hypothesis Supported by Epidemiological, Anatomopathological, Molecular, and Physiological Findings

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccine-induced myocarditis is a rare but well-documented complication in young males. The increased incidence of sudden death among athletes following vaccination has been reported and requires further investigation. Whether the risk of myocarditis, a known major cause of sudden death in young male athletes, also increases after coronavirus disease 2019 (COVID-19) infection is unknown. The severity and implications of these critical adverse effects require a thorough analysis to elucidate their key triggering mechanisms. The present review aimed to evaluate whether there is a justification to hypothesize that catecholamines in a "hypercatecholaminergic" state are the key trigger of SARS-CoV-2 mRNA vaccine-induced myocarditis and related outcomes and whether similar risks are also present following COVID-19 infection. A thorough, structured scoping review of the literature was performed to build the hypothesis through three pillars: detection of myocarditis risk, potential alterations and abnormalities identified after SARS-CoV-2 mRNA vaccination or COVID-19 infection and consequent events, and physiological characteristics of the most affected population. The following terms were searched in indexed and non-indexed peer review articles and recent preprints (<12 months): agent, "SARS-CoV-2" or "COVID-19"; event, "myocarditis" or "sudden death(s)" or "myocarditis+sudden death(s)" or "cardiac event(s)"; underlying cause, "mRNA" or "spike protein" or "infection" or "vaccine"; proposed trigger, "catecholamine(s)" or "adrenaline" or "epinephrine" or "noradrenaline" or "norepinephrine" or "testosterone"; and affected population, "young male(s)" or "athlete(s)." The rationale and data that supported the hypothesis were as follows: SARS-CoV-2 mRNA vaccine-induced myocarditis primarily affected young males, while the risk was not observed following COVID-19 infection; independent autopsies or biopsies of patients who presented post-SARS-CoV-2 mRNA vaccine myocarditis in different geographical regions enabled the conclusion that a primary hypercatecholaminergic state was the key trigger of these events; SARS-CoV-2 mRNA was densely present, and SARS-CoV-2 spike protein was progressively produced in adrenal medulla chromaffin cells, which are responsible for catecholamine production; the dihydroxyphenylalanine decarboxylase enzyme that converts dopamine into noradrenaline was overexpressed in the presence of SARS-CoV-2 mRNA, leading to enhanced noradrenaline activity; catecholamine responses were physiologically higher in young adults and males than in other populations; catecholamine responses and resting catecholamine production were higher in male athletes than in non-athletes; catecholamine responses to stress and its sensitivity were enhanced in the presence of androgens; and catecholamine expressions in young male athletes were already high at baseline, were higher following vaccination, and were higher than those in non-vaccinated athletes. The epidemiological, autopsy, molecular, and physiological findings unanimously and strongly suggest that a hypercatecholaminergic state is the critical trigger of the rare cases of myocarditis due to components from SARS-CoV-2, potentially increasing sudden deaths among elite male athletes.

Stress effects on the oddball P300 and N2 in males and females

We examined the effect of psychosocial stress on electrophysiological markers of novelty and deviance processing, the N2 and P300, as well as sex differences therein. Participants underwent the Trier Social Stress Test (TSST) or a control procedure, followed by an oddball paradigm. A physiological stress response was induced in both sexes in the TSST condition. Furthermore, a reduced target P300 amplitude was elicited in the TSST condition in fronto-central electrodes, an effect that did not differ in magnitude between both sexes. By contrast, stressor effects on N2 amplitude differed by sex: In females, N2 amplitude was decreased in the TSST condition, while in males, no stress effects were observed. Exploratory correlational analyses suggested that a stress-induced P300 amplitude reduction, at least in males, could be due to a modulation of adrenergic activity. These results are consistent with sex differences in the manner in which stress affects lower-level, stimulus-driven vs. higher-level, more controlled processing stages.

First Demonstration of Double Dissociation between COMT-Met158 and COMT-Val158 Cognitive Performance When Stressed and When Calmer

We present here the first evidence of the much-predicted double dissociation between the effect of stress on cognitive skills [executive functions (EFs)] dependent on prefrontal cortex (PFC) by catechol-O-methyltransferase (COMT) genotype. The COMT gene polymorphism with methionine (Met) at codon 158 results in more dopamine (DA) in PFC and generally better EFs, while with valine (Val) at codon 158 the result is less PFC DA and generally poorer EFs. Many have predicted that mild stress, by raising PFC DA levels should aid EFs of COMT-Vals (bringing their PFC DA levels up, closer to optimal) and impair EFs of COMT-Mets (raising their PFC DA levels past optimal). We tested 140 men and women in a within-subject crossover design using extremely mild social evaluative stress. On trials requiring EFs (incongruent trials) of the Flanker/Reverse Flanker task, COMT-Val158 homozygotes performed better when mildly stressed than when calmer, while COMT-Met158 carriers performed worse when mildly stressed. Two other teams previously tried to obtain this, but only found stress impairing EFs of COMT-Mets, not improving EFs of COMT-Vals. Perhaps we found both because we used a much milder stressor. Evidently, the bandwidth for stress having a facilitative effect on EFs is exceedingly narrow.

Influence of prenatal stress on metabolic abnormalities induced by postnatal intake of a high-fat diet in BALB/c mice

Prenatal insults during fetal development result in increased likelihood of developing chronic disease. Obesity, the biggest risk factor for the development of metabolic disease, is affected by several genetic and environmental factors. High-fat diet (HFD) consumption is usually linked with the development of obesity. The main goal of this study was to analyze the impact of the exposure to a HFD in prenatally stressed animals. For this purpose, we subjected pregnant BALB/c mice to restraint stress for 2 h a day between gestational day (GD) 14 and GD 21. Prenatally stressed and control offspring of both sexes were postnatally exposed to a HFD for 24 weeks. We found that prenatal stress (PS) per se produced disturbances in males such as increased total blood cholesterol and triglycerides, with a decrease in mRNA expression of sirtuin-1. When these animals were fed a HFD, we observed a rise in glucose and insulin levels and an increase in visceral adipose tissue gene expression of leptin, resistin, and interleukin-1 beta. Although females proved to be more resilient to PS consequences, when they were fed a HFD, they showed significant metabolic impairment. In addition to the changes observed in males, females also presented an increase in body weight and adiposity and a rise in cholesterol levels.

Can Acupuncture Treatment of Hypertension Improve Brain Health? A Mini Review

With age, cerebrovascular and neurodegenerative diseases (e.g., dementia and Alzheimer’s) are some of the leading causes of death in the United States. Related to these outcomes is the increased prevalence of hypertension, which independently increases the development of cerebrovascular and neurodegenerative diseases. While a direct mechanistic link between hypertension and poor brain health is unknown, many hypothesize that the etiology stems from poor blood pressure (BP) and cerebrovascular regulation. This dysfunction fosters hypoperfusion of the brain, causing stress to the tissue through a nutrient mismatch, subtly damaging the brain over many years. Current Western medical treatment relies on pharmacological treatment (mainly beta-blockers, angiotensin-converting enzyme inhibitors, or a combination of the two). However, Western treatments have not been successful in mitigating brain health outcomes and are burdened with unwanted side effects and non-adherence issues. Alternatively, traditional East Asia medicine has used acupuncture as a treatment for hypertension and may offer a promising approach in response to the limitations of conventional therapy. While detailed clinical and mechanistic experimental evidence is lacking, acupuncture has been observed to reduce BP and improve endothelial function in hypertensive adults. Further, acupuncture has been shown to have specific cerebrovascular effects, increasing cerebrovascular reactivity in healthy adults, highlighting possible neuroprotective properties. Therefore, our review is aimed at evaluating acupuncture as a treatment for hypertension and the potential impact on brain health. We will interrogate the current literature as well as discuss the proposed neural and vascular mechanisms by which acupuncture acts.

The impact of early life stress on the central oxytocin system and susceptibility for drug addiction: Applicability of oxytocin as a pharmacotherapy

Early life trauma is strongly associated with an increased vulnerability to abuse illicit drugs and the impairment of neural development. This includes alterations to the development of the oxytocin system, which plays a pivotal role in the regulation of social behaviours and emotion. Dysregulation of this important system also contributes to increased susceptibility to develop drug addiction. In this review, we provide an overview of the animal models of early life stress that are widely used, and discuss the impact that early life stress has on drug-taking behaviour in adolescence and adulthood in both sexes. We link this to the changes that early life stress has on the endogenous oxytocin system, and how exogenously administered oxytocin may help to re-establish functioning of the system, and in turn, reduce drug-taking behaviour.

Early maternal separation induces preference for sucrose and aspartame associated with increased blood glucose and hyperactivity

Early life stress and exposure to sweeteners lead to physiological and behavioral alterations in adulthood. Nevertheless, many genetic and environmental factors as well as the neurobiological mechanisms that contribute to the development of these disorders are not fully understood. Similarly, evidence about the long-term metabolic effects of exposure to sweeteners in early life is limited and inconsistent. This study used an animal model of maternal separation during breastfeeding (MS) to analyze the effects of early life stress on consumption of sweeteners, weight gain, blood glucose and locomotion. Rats were housed under a reversed light/dark cycle (lights off at 7:00 h) with ad libitum access to water and food. In the MS protocol, MS pups were separated from the dam for 6 h per day in two periods of 180 minutes (7:00-10:00 and 13:00-16:00 h) during the dark phase of postnatal day (PND) 1 to PND 21. Non-separated (NS) pups served as controls. On PND 22 rats were grouped by sex and treatment. From PND 26 to PND 50 sucrose and aspartame were provided to rats, and sweetener intake, body weight and blood glucose-related measures were scored. On PND 50, both male and female rats were exposed to the open field test to obtain locomotion and anxiety-related measures. Results showed that both early maternal separation and sweetener intake during adolescence resulted in increased blood glucose and hyperactivity in male rats but not in female rats. Data suggest that the combination of early stress and exposure to sucrose and aspartame could be a risk factor for the development of chronic diseases such as diabetes, as well as for behavioral alterations.

Long Exercise Test in the Interattack Period of Periodic Paralysis: A Useful and Sensitive Diagnostic Tool

PURPOSE

The reference values of long exercise test are inconsistent in previous studies. Our research aims to determine the reference values and improve diagnostic efficiency of long exercise test in periodic paralysis.

METHODS

In this study, 100 healthy controls, 35 non-periodic paralysis patients, and 47 patients with periodic paralysis were recruited. The procedures of long exercise test were conducted following McMannis(1986) method.

RESULTS

The decrease rate in compound muscle action potential amplitudes was correlated with gender, and it was not influenced by age, height, weight, and exercise. After analyzing receiver operating characteristic curves, the compound muscle action potential amplitude decrease rate was stratified by sex. The mean area under the curve, sensitivity, and specificity were higher in male and female than all pooled subjects. The reference values of compound muscle action potential amplitude decrease rate were 46.8% in male and 26.9% in female, respectively.

CONCLUSIONS

The long exercise test is a useful and sensitive diagnostic tool for primary periodic paralysis and thyrotoxic periodic paralysis. However, the reference values should be set by sex, which has better diagnostic performance, sensitivity, and specificity.

Effects of perinatal diet and prenatal stress on the behavioural profile of aged male and female rats

The present work studies whether chronic prenatal stress (PS) influences the long-term sex-dependent neuropsychological status of offspring and the effects of an early dietary intervention in the dam. In addition, dams were fed with either a high-fat sugar diet (HFSD) or methyl donor supplemented diet (MDSD). PS procedure did not affect body weight of the offspring. MDSD induced decreases in body weight both in male and female offspring (1 month) that were still present in aged rats. HFSD induced an increase in body weight both in male and female offspring that did not persist in aged rats. In the Porsolt forced swimming test, only young males showed increases in immobility time that were reversed by MDSD. In old female rats (20 months), PS-induced cognitive impairment in both the novel object recognition test (NORT) and in the Morris water maze that was reversed by MDSD, whereas in old males, cognitive impairments and reversion by MDSD was evident only in the Morris water maze. HFSD induced cognitive impairment in both control and PS old rats, but there was no additive effect of PS and HFSD. It is proposed here that the diversity of symptoms following PS could arise from programming effects in early brain development and that these effects could be modified by dietary intake of the dam.

Excess intake of fat and sugar potentiates epinephrine-induced hyperglycemia in male rats

AIMS

Over the past five decades, per capita caloric intake has increased significantly, and diet- and stress-related diseases are more prevalent. The stress hormone epinephrine stimulates hepatic glucose release during a stress response. The present experiment tested the hypothesis that excess caloric intake alters this ability of epinephrine to increase blood glucose.

METHODS

Sprague-Dawley rats were fed a high-energy cafeteria-style diet (HED). Weight gain during the first 5 days on the diet was used to divide the rats into an HED-lean group and HED-obese group. After 9 weeks, the rats were injected with epinephrine, and blood glucose was measured.

RESULTS

HED-obese rats gained body and fat mass, and developed insulin resistance (IR) and hepatic steatosis. HED-lean and control rats did not differ. Epinephrine produced larger increases in blood glucose in the HED-obese rats than in the HED-lean and control rats. Removing the high-energy components of the diet for 4 weeks reversed the potentiated effects of epinephrine on glucose and corrected the IR but not the steatosis or obesity.

CONCLUSIONS

Consumption of a high-energy cafeteria diet potentiates epinephrine-induced hyperglycemia. This effect is associated with insulin resistance but not adiposity or steatosis and is reversed by 4 weeks of standard chow.

Do venepuncture procedures induce cortisol responses? A review, study, and synthesis for stress research

Venepuncture procedures are frequently employed to continuously monitor humoral stress markers. As such procedures are conceived as "potent psychological and physiological stressors", there is a need to determine whether venepuncture procedures themselves elicit cortisol responses and if so, how to deal with them appropriately. In order to assess the rate of cortisol responses to venepuncture, we conducted a literature review, which suggested that venepuncture procedures induce cortisol responses with a probability of approximately 30%. By utilizing Bayesian analysis, this result was integrated with the cortisol data of 18 healthy men who were exposed to a venepuncture procedure twice (time lag: 1 week). The currently observed response rate of 47% differed substantially from the earlier findings, which we attribute to a self-selective sampling of participants. In addition, participants showing a response to the first venepuncture were highly likely to also show a response to the second one. In this regard, we discuss the presumed conditioning of cortisol responses to venepuncture procedures. To prevent the superposition of venepuncture-induced cortisol responses and responses induced by target stressors, we propose a time- and selection-based strategy: cortisol samples taken about 110min after venepuncture should be virtually adjusted for its superimposing effects. Furthermore, previous experiences of venepuncture were highly predictive for cortisol responsiveness. This association could be utilized in further studies to identify participants who will probably show a cortisol response to venepuncture.

Thyrotoxic periodic paralysis: clinical challenges

Thyrotoxic periodic paralysis (TPP), a disorder most commonly seen in Asian men, is characterized by abrupt onset of hypokalemia and paralysis. The condition primarily affects the lower extremities and is secondary to thyrotoxicosis. The underlying hyperthyroidism is often subtle causing difficulty in early diagnosis. Factors like high-carbohydrate meal exercise, steroid, and stress can precipitate an attack of TPP. Evidence is building up showing role of genetic mutations in Kir2.6 channel in the pathogenesis of TPP. Loss of function of Kir2.6 together with increased activity of Na(+)/K(+) ATPase may trigger a positive feed-forward cycle of hypokalemia. Biochemical hyperthyroidism with normal urinary potassium excretion and ECG changes are characteristic of TPP. Treatment with low-dose potassium supplements and nonselective beta-blockers should be initiated upon diagnosis, and the serum potassium level should be frequently monitored to prevent rebound hyperkalemia.

Cardiovascular reactivity, stress, and physical activity

Psychological stress has been proposed as a major contributor to the progression of cardiovascular disease (CVD). Acute mental stress can activate the sympathetic-adrenal-medullary (SAM) axis, eliciting the release of catecholamines (NE and EPI) resulting in the elevation of heart rate (HR) and blood pressure (BP). Combined stress (psychological and physical) can exacerbate these cardiovascular responses, which may partially contribute to the elevated risk of CVD and increased proportionate mortality risks experienced by some occupations (e.g., firefighting and law enforcement). Studies have supported the benefits of physical activity on physiological and psychological health, including the cardiovascular response to acute stress. Aerobically trained individuals exhibit lower sympathetic nervous system (e.g., HR) reactivity and enhanced cardiovascular efficiency (e.g., lower vascular reactivity and decreased recovery time) in response to physical and/or psychological stress. In addition, resistance training has been demonstrated to attenuate cardiovascular responses and improve mental health. This review will examine stress-induced cardiovascular reactivity and plausible explanations for how exercise training and physical fitness (aerobic and resistance exercise) can attenuate cardiovascular responses to stress. This enhanced functionality may facilitate a reduction in the incidence of stroke and myocardial infarction. Finally, this review will also address the interaction of obesity and physical activity on cardiovascular reactivity and CVD.

A 10-year analysis of thyrotoxic periodic paralysis in 135 patients: focus on symptomatology and precipitants

BACKGROUND

A comprehensive analysis has not been performed on patients with thyrotoxic periodic paralysis (TPP) characterized by acute hypokalemia and paralysis in the setting of thyrotoxicosis.

PURPOSE

The aim of this study was to analyze the detailed symptomatology of thyrotoxicosis and precipitating factors for the attack in a large cohort of TPP patients.

PATIENTS AND METHODS

A prospective observational study enrolled patients with TPP consecutively over 10 years at an academic medical center. Clinical features, including signs/symptoms of thyrotoxicosis and precipitating factors, were analyzed. The Wayne's index was used to assess the severity of thyrotoxicosis at presentation. Patients who agreed to receive an oral glucose-loading test after recovery were evaluated.

RESULTS

Among the 135 TPP patients (male:female, 130:5), 70% of paralytic attacks occurred in the morning, especially during the seasons of summer and fall. Two-thirds of patients did not have a known family or personal history of hyperthyroidism. Only 17% of TPP patients manifested overt signs/symptoms of thyrotoxicosis (Wayne's index >19). A clear precipitating factor, such as high carbohydrate load, acute upper respiratory tract infection, strenuous exercise, high-salt diet, or the use of steroids or bronchodilators, was identified in only 34% of TPP patients. A glucose load to stimulate insulin secretion induced acute hypokalemia (K(+)2.47±0.6 mmol/l) with reparalysis in only 18% (10/55) of TPP patients.

CONCLUSIONS

Most TPP patients have only subtle clinical signs/symptoms of thyrotoxicosis and only a small fraction has clear precipitating factors. In addition to the effects of hyperinsulinemia, other insulin-independent mechanisms may participate in the pathogenesis of TPP.

New, normative, English-sample data for the Short Form Perceived Stress Scale (PSS-4)

This article provides population norms for the Short Form Perceived Stress Scale (PSS-4) and investigates the relationship between PSS-4 scores and sociodemographic variables. The PSS-4 was administered to an English sample (n = 1568) and was found to have acceptable psychometric properties. Sociodemographic variables explained 19.5% of variance in PSS-4 scores, and mean PSS-4 scores were significantly different from the mean scores reported in Cohen and Williamson's original study. Greater levels of perceived health status, greater levels of social support, being male and being older were predictive of lower PSS-4 scores. Norm values for interpreting PSS-4 scores are presented.

Stress-Induced Cortisol Response and Fat Distribution in Women

Recent studies have shown an association between uncontrollable stress and abdominal fat distribution. It has been suggested that changes in cortisol secretion might represent one possible mechanism for this relationship. This study investigated whether body fat distribution, determined by waist-to-hip ratio (WHR), is related to salivary cortisol levels in response to laboratory stressors. Subjects were 41 overweight women with a Low or a High WHR. Multiple measures of cortisol and mood were obtained during a session of stressful tasks (eg., timed arithmetic) and during a time-matched, control rest session. Also, background life stress and psychological trait variables were assessed. Compared to Low WHR subjects, High WHR subjects secreted significantly more cortisol during the stressful session after 60 minutes of stress, and considering the total area under the curve of secretion. This difference was not seen on the rest day. In terms of background and psychological measures, High WHR subjects were characterized by poorer coping skills and differences in mood reactivity. Specifically, although all subjects became more angry in response to the stressful session, High WHR subjects showed smaller increases in anger. This could indicate that they are more likely to evidence a helpless reaction to uncontrollable stress. These findings support the hypothesis that cortisol secretion might represent a mechanism for the observed association between stress and abdominal fat distribution. Furthermore, differences in coping and appraisal may suggest that a particular psychological pattern might influence the reactivity of the adrenal-cortical system to stress, and subsequent fat distribution.

Postnatal maternal separation modifies the response to an obesogenic diet in adulthood in rats

An early-life adverse environment has been implicated in the susceptibility to different diseases in adulthood, such as mental disorders, diabetes and obesity. We analyzed the effects of a high-fat sucrose (HFS) diet for 35 days in adult female rats that had experienced 180 minutes daily of maternal separation (MS) during lactancy. Changes in the obesity phenotype, biochemical profile, levels of glucocorticoid metabolism biomarkers, and the expression of different obesity- and glucocorticoid-metabolism-related genes were analyzed in periovaric adipose tissue. HFS intake increased body weight, adiposity and serum leptin levels, whereas MS decreased fat pad masses but only in rats fed an HFS diet. MS reduced insulin resistance markers but only in chow-fed rats. Corticosterone and estradiol serum levels did not change in this experimental model. A multiple gene expression analysis revealed that the expression of adiponutrin (Adpn) was increased owing to MS, and an interaction between HFS diet intake and MS was observed in the mRNA levels of leptin (Lep) and peroxisome proliferator-activated receptor gamma coactivator 1 alpha (Ppargc1a). These results revealed that early-life stress affects the response to an HFS diet later in life, and that this response can lead to phenotype and transcriptomic changes.

Stress cardiomyopathy: diagnosis, pathophysiology, management, and prognosis

Stress cardiomyopathy is now a well-recognized reversible cardiomyopathy, with a clinical presentation mimicking Acute Coronary syndrome in the absence of significant coronary artery disease. It is often encountered in postmenopausal females and is usually precipitated by acute emotional or physical stressors. In this review, we have attempted to summarize relevant data regarding diagnosis, typical and atypical presentations, pathophysiology, management options, and prognosis. Typically, patients present with chest pain and shortness of breath, transient electrocardiographic changes, moderate troponin elevation, and are found to have wall motion abnormalities (apical and midventricular akinesis with preserved basal segment systolic function) without obstructive coronary lesions, with complete resolution in next few weeks. The precise pathophysiology remains unclear, but excessive catecholamine stimulation, metabolic disturbances, and dysfunction of microcirculation are thought to be the underlying mechanisms.

Behavioral and perceived stressor effects on urinary catecholamine excretion in adult Samoans

OBJECTIVES

The effects of perceptions and behaviors related to culturally patterned socioeconomic obligations on catecholamine excretion rates were studied in a cross-sectional sample of Samoan adults.

METHODS

A total of 378 participants, ages 29-62 years, from 9 villages throughout Samoa, provided timed overnight urine specimens, and self-reported perceptions and behaviors associated with contributions to one's family, aiga, and chief, matai, and communal gift exchanges, fa'alavelave. Urinary norepinephrine and epinephrine excretion rates were measured by high performance liquid chromatography with electrochemical detection. Age (≤40 vs. >40 years) and gender-specific regression models were estimated to detect associations with catecholamine excretion.

RESULTS

Young women who contribute more to their matai, who consider fa'alavelave to be a financial strain, and who view their contribution to their matai to be "just right," had significantly higher residence-adjusted norepinephrine excretion. Young women who contribute more to their matai, who consider fa'alavelave to be a financial strain, and who consider their contribution to their aiga not to be a burden, had higher epinephrine excretion. Older men who contribute more to their aiga and who perceive their contribution to their aiga to be "just right" had increased residence-adjusted epinephrine excretion.

CONCLUSIONS

Individual-level perceptions and behaviors related to traditional socioeconomic obligations are a significant correlate of increased overnight catecholamine excretion rates. Higher excretion rates may be attributed to psychosocial stress arousal associated with a discordance between personal desires for upward social mobility, and family and community-based socioeconomic obligations. Changes in patterns of individual-level psychosocial stress arousal may contribute to cardiovascular disease risk in modernizing Samoans.

Sex differences in physiological and affective responses to stress in remitted depression

Major depressive disorder (MDD) is associated with alterations in stress physiology. Severe melancholic depression is characterized by hypercortisolism, but community dwelling mildly depressed individuals and those with remitted MDD have shown reduced or normal reactivity to stress. There are also pronounced sex differences both in the incidence of MDD and in stress reactivity. To explore the relationships among depression history, sex differences, and stress, we examined stress reactivity in people with and without a history of MDD. Twenty-two participants with remitted MDD (12 men and 10 women) and 36 never depressed comparison participants (22 men and 14 women) participated in the study. Cortisol and alpha-amylase (sAA) were sampled from saliva before, 10 min after, and 30 min after the Trier Social Stress Test (TSST). Participants filled out the Positive Affect Negative Affect Schedule (PANAS) before and after they underwent the TSST. Women with remitted MDD showed reduced cortisol response to the TSST compared with the never MDD women, while men with remitted MDD showed comparable cortisol reactivity to the never depressed men. The groups did not differ on sAA reactivity to stress. The remitted MDD group (overall and men and women separately) reported greater negative affect both before and after stress compared to the never depressed group. Women from both groups reported greater post-stress negative affect than men. In contrast, men from both groups reported higher positive affect before and after stress than women. Given that the sex difference findings were not dependent on depression history, self-reported affective differences in response to stress may predate depressive symptoms and contribute to sex differences in depression incidence.

Ecological and sociodemographic effects on urinary catecholamine excretion in adult Samoans

BACKGROUND

Ecological and sociodemographic correlates of stress may contribute to cardiovascular disease risk in modernizing Samoans.

AIM

The effects of peri-urban vs rural residence, education, occupation, caffeine intake and cigarette consumption on urinary catecholamine excretion were studied in Samoan adults.

SUBJECTS AND METHODS

Five hundred and seven participants, aged 29-69 years, were randomly selected from nine villages throughout Samoa. Sociodemographic and lifestyle factors were assessed by questionnaire. Epinephrine and norepinephrine excretion rates were measured by high performance liquid chromatography with electrochemical detection in overnight urine samples. Age ( ≤ 40 vs >40 years) and gender-specific regression models were estimated to detect associations with BMI-adjusted catecholamine excretion.

RESULTS

Norepinephrine was significantly higher in peri-urban young men and older women. Epinephrine was significantly higher in peri-urban older men. Adjustment for caffeine attenuated the relationship between residence and norepinephrine in young women.

CONCLUSION

General residential exposure to modernization in urban villages is a significant correlate of increased overnight catecholamine excretion rates and is consistent with past studies. Caffeine consumption in younger women plays a complex role in stress-related catecholamine excretion. Further studies of individual level attitudinal and behavioural factors in Samoans are needed to understand psychosocial stress, physiologic arousal and health.

Role of the excessive amounts of circulating catecholamines and glucocorticoids in stress-induced heart disease

Various stressful stimuli are known to activate the sympathetic nervous system to release catecholamines and the hypothalamic-pituitary-adrenal axis to release glucocorticoids in the circulation. Although initial actions of both catecholamines and glucocorticoids are beneficial for the function of the cardiovascular system, their delayed effects on the heart are deleterious. Glucocorticoids not only increase plasma levels of catecholamines by inhibiting their extraneuronal uptake, but they have also been shown to induce supersensitivity to catecholamines in the heart by upregulating different components of the betta-adrenoceptor signal transduction system. Low concentrations of catecholamines stimulate the heart by promoting Ca2+ movements, whereas excessive amounts of catecholamines produce cardiac dysfunction by inducing intracellular Ca2+ overload in cardiomyocytes. Several studies have shown, however, that under stressful conditions high concentrations of catecholamines become oxidized to form aminolutins and generate oxyradicals. These oxidation products of catecholamines have been demonstrated to produce coronary spasm, arrhythmias, and cardiac dysfunction by inducing Ca2+-handling abnormalities in both sarcolemmal and sarcoplasmic reticulum, defects in energy production by mitochondria, and myocardial cell damage. In this article we have focused the discussion to highlight the interrelationship between catecholamines and glucocorticoids and to emphasize the role of oxidation products of catecholamines in the development of stress-induced heart disease.

Transient cardiac ballooning--the syndrome

Transient cardiac ballooning is usually a reversible clinical entity. A patient typically presents with chest pain, electrocardiogram (ECG) abnormalities like ST-segment elevation (most commonly reported) or depression, and elevated cardiac enzymes, but has no or nonobstructive coronary artery disease. Left ventriculography reveals transient akinesis of the involved portion of the myocardial wall with compensatory hyperkinesis of the remaining myocardium, leading to ballooning of the noncontracting myocardial wall during systole. Acute regional myocardial dysfunction ensues, which normalizes on average within 1 to 6 weeks. The hypotheses for these pathophysiologic changes range from direct cardiac myocyte injury to postischemic myocardial stunning to neurotransmitter actions. The objective of this article is to present a succinct description of a small case series accompanied with various recently reported presentations and morphology by left ventriculogram and a detailed review of available data on underlying pathophysiology. In addition, a discussion on current diagnostic guidelines, treatment, prognosis, and potential future investigations is included.

Sex-specific dissociations in autonomic and HPA responses to stress and cues in alcohol-dependent patients with cocaine abuse

AIMS

Chronic alcohol and drug dependence leads to neuroadaptations in hypothalamic-pituitary-adrenal (HPA) and sympathetic adrenal medullary (SAM) stress systems, which impact response sensitivity to stress and alcohol cue and facilitates risk of relapse. To date, gender variations in these systems have not been fully assessed in abstinent alcohol-dependent individuals who also met criteria for cocaine abuse.

METHODS

Forty-two (21 M/21 F) early abstinent treatment-seeking substance-abusing (SA) men and women and 42 (21 M/21 F) healthy control (HC) volunteers were exposed to three 5-min guided imagery conditions (stress, alcohol/drug cue, neutral relaxing), presented randomly, one per day across three consecutive days. Alcohol craving and anxiety ratings were obtained as well as measures of heart rate (HR), blood pressure, plasma ACTH, cortisol, norepinephrine (NE) and epinephrine (EPI).

RESULTS

SA males showed increased ACTH and EPI basal tone compared with HC males and SA females. However, they demonstrated no increase in ACTH and cortisol levels following stress and alcohol cue imagery exposure compared to the neutral condition. SA females demonstrated a typically increased stress response in both measures. In addition, SA males showed no increase in cardiovascular response to either stress or cue, and no increase in catecholamine response to cue compared with their response to neutral imagery. Again, this dampening was not observed in HC males who produced significantly higher levels of cue-related HR and EPI, and significantly higher stress-related DBP. In contrast, SA females showed an enhanced ACTH and cortisol response to stress and cue compared with neutral imagery and this was not observed in the HC females. They also demonstrated a reduced increase in NE and EPI compared with both SA males and HC females as well as reduced HR compared with HC females.

CONCLUSIONS

While SA males showed a generalized suppression of HPA, SAM system and cardiovascular markers following both stress and cue, SA women demonstrated a selective sympatho-adrenal suppression to stress only and an enhanced HPA response to both stress and cue. These gender variations are discussed in terms of their potential impact on relapse vulnerability and treatment outcome.

Sex differences in drug-related stress-system changes: implications for treatment in substance-abusing women

Extensive research indicates that chronic substance abuse disrupts stress and reward systems of the brain. Gender variation within these stress-system alterations, including the impact of sex hormones on these changes, may influence sex-specific differences in both the development of, and recovery from, dependency. As such, gender variations in stress-system function may also provide a viable explanation for why women are markedly more vulnerable than men to the negative consequences of drug use. This article therefore initially reviews studies that have examined gender differences in emotional and biophysiological changes to the stress and reward system following the acute administration of drugs, including cocaine, alcohol, and nicotine. The article then reviews studies that have examined gender differences in response to various types of stress in both healthy and drug-abusing populations. Studies examining the impact of sex hormones on these gender-related responses are also reported. The implications of these sex-specific variations in stress and reward system function are discussed in terms of both comorbid psychopathology and treatment outcome.

Physiological and psychological reactions to work in men and women with identical job tasks

Differences in physiological functioning in the hypothalamus-pituitary-adrenal cortex axis and the autonomic nervous system have been suggested to contribute to many of the health differences that may be observed between men and women as well as being relevant for the development of musculoskeletal pain. To clarify whether men and women with identical work tasks reacted differently when doing work known to induce musculoskeletal pain, ratings and physiological measurements were obtained at work start (15:30) and at the end of the workshift (22:30) on 17 men and 20 women. Men showed a larger decrease in perceived energy levels during the workshift but there were no differences between men and women as regards cortisol, adrenaline, noradrenaline, heart-rate activation, perceived stress, pain and physical exertion. In conclusion, differential physiological activation during the workshift seem to be an unlikely mechanism for explaining gender differences in pain associated with exposure to awkward and repetitive movements.

Sex differences in skilled movement in response to restraint stress and recovery from stress

Sex differences exist in skilled movement, and skilled motor performance is also influenced by stress. As shown for cognitive function, the effects of stress are usually characterized by considerable sexual dimorphism. The purpose of this study was to investigate sex differences in skilled motor function in response to stress. Male and female Long-Evans rats were trained and tested in skilled reaching and skilled walking tasks. Both groups of animals were then exposed to daily restraint stress for 15 days. Recovery from daily stress was assessed by comparing reaching performance at 10 min versus 60 min after restraint stress, and recovery from chronic stress was tested for 21 days after cessation of stress. Animals were tested daily in skilled reaching for the entire period. Observations showed that females performed significantly better than males during the stress period in terms of reaching success and number of attempts needed to grasp a food pellet. No difference between testing at 10 or 60 min after daily stress was found. Analysis of movement patterns and recovery from stress indicated that males and females use different strategies to overcome stress-induced motor disturbance. While male rats preferred to use original movement patterns, females tended to modify these patterns in order to increase reaching success. Modification of movement patterns in female rats was accompanied by a faster recovery in success rate after the cessation of stress. These results indicate sex differences in skilled reaching in response to stress, and in the recovery period after stress.

Fasting differentially modulates the immunological system: its mechanism and sex difference

The immunological properties and hormonal metabolism in rodents are affected by physical and psychological stress more strongly in males than in females. To elucidate the mechanism and physiological significance of the sex difference in the susceptibility of animal to stresses, changes in the immunological system in plasma and intestine and hormonal status in plasma were compared among 8-week-old male and female ICR mice before and after fasting. During the fasting of animals, the expression of immunoglobulin A in intestinal mucosa, and cortisol, interleukin-10 and interferon-gamma in plasma increased. These changes occurred more apparently in males than in females. Under identical conditions, the plasma levels of testosterone decreased markedly with concomitant occurrence of apoptosis in the testis, while the plasma levels of estradiol decreased calmly, and no appreciable apoptosis occurred in the ovary. These results indicate that testosterone enhances the stress-induced modulation of the immune system by some mechanism that was antagonized by estradiol.

Catecholamines and the effects of exercise, training and gender

Stress hormones, adrenaline (epinephrine) and noradrenaline (norepinephrine), are responsible for many adaptations both at rest and during exercise. Since their discovery, thousands of studies have focused on these two catecholamines and their importance in many adaptive processes to different stressors such as exercise, hypoglycaemia, hypoxia and heat exposure, and these studies are now well acknowledged. In fact, since adrenaline and noradrenaline are the main hormones whose concentrations increase markedly during exercise, many researchers have worked on the effect of exercise on these amines and reported 1.5 to >20 times basal concentrations depending on exercise characteristics (e.g. duration and intensity). Similarly, several studies have shown that adrenaline and noradrenaline are involved in cardiovascular and respiratory adjustments and in substrate mobilization and utilization. Thus, many studies have focused on physical training and gender effects on catecholamine response to exercise in an effort to verify if significant differences in catecholamine responses to exercise could be partly responsible for the different performances observed between trained and untrained subjects and/or men and women. In fact, previous studies conducted in men have used different types of exercise to compare trained and untrained subjects in response to exercise at the same absolute or relative intensity. Their results were conflicting for a while. As research progressed, parameters such as age, nutritional and emotional state have been found to influence catecholamine concentrations. As a result, most of the recent studies have taken into account all these parameters. Those studies also used very well trained subjects and/or more intense exercise, which is known to have a greater effect on catecholamine response so that differences between trained and untrained subjects are more likely to appear. Most findings then reported a higher adrenaline response to exercise in endurance-trained compared with untrained subjects in response to intense exercise at the same relative intensity as all-out exercise. This phenomenon is referred to as the 'sports adrenal medulla'. This higher capacity to secrete adrenaline was observed both in response to physical exercise and to other stimuli such as hypoglycaemia and hypoxia. For some authors, this phenomenon can partly explain the higher physical performance observed in trained compared with untrained subjects. More recently, these findings have also been reported in anaerobic-trained subjects in response to supramaximal exercise. In women, studies remain scarce; the results are more conflicting than in men and the physical training type (aerobic or anaerobic) effects on catecholamine response remain to be specified. Conversely, the works undertaken in animals are more unanimous and suggest that physical training can increase the capacity to secrete adrenaline via an increase of the adrenal gland volume and adrenaline content.

Effects of maternal separation on hypothalamic-pituitary-adrenal responses, cognition and vulnerability to stress in adult female rats

We studied the long term effects of neonatal stress in female rats and subsequent responses to stress when adults. Female rats that experienced maternal separation (MS) showed in adulthood depressive-like behavior in the forced swimming test and cognitive impairments in the novel object recognition test, which were reverted by the glucocorticoid receptor antagonist mifepristone or the beta-adrenoceptor antagonist propranolol. Markers of HPA axis (corticosterone levels, CRF mRNA levels in the paraventricular nucleus and glucocorticoid receptor density in the hippocampus) were altered by MS, suggesting that an altered HPA axis function may be associated to behavioral and cognitive deficits in MS female rats. In addition, MS rats were found to be more vulnerable to chronic stress than controls as shown by decreases in open field activity, increases in immobility time in the forced swim test, and changes in markers of HPA axis (decreases in the density of glucocorticoid receptors). These present findings are discussed in terms of gender differences in adulthood.

Evaluation of the NITV CVSA

The purpose of this study was to evaluate a commonly used voice stress analyzer, the National Institute of Truth Verification's (NITV) Computer Voice Stress Analyzer (CVSA), using a speech database containing materials recorded (i) in the laboratory, while highly controlled deceptive and shock-induced stress levels were systematically varied, and (ii) during a field procedure. Subjects were 24 each males/females (age range 18-63 years) drawn from a representative population. All held strong views on an issue and were required to make sharply derogatory statements about it. The CVSA system was then evaluated in a double-blind study using three sets of examiners: (i) two UF scientists trained/certified by NITV in CVSA operation, (ii) three experienced NITV operators provided by the manufacturer and (iii) five experimental phoneticians. The results showed that the "true positive" (or hit) rates for all examiners ranged from chance to somewhat higher levels (c. 50-65%) for all conditions and types of materials (e.g., stress vs. unstressed, truth vs. deception). However, the false-positive rate was just as high - often higher. Sensitivity statistics demonstrated that the CVSA system operated at about chance level.

Tako-Tsubo-Like Syndrome with Atypical Clinical Presentation: Case Report and Literature Review

A 78-year-old woman presented herself at emergency for the appearance of severe dyspnea. An electrocardiogram showed signs of inferior and anterior necrosis, and laboratory tests showed a small increase of myocardial cytonecrosis enzymes. An echocardiogram detected a reduction of global systolic function (ejection fraction [EF] approximately 40%) as well as akinesia of the apex, interventricular septum middle segments, and anterior and anterolateral walls, with basal segments showing compensatory hyperkinesia. The coronarography showed a coronary tree substantially free from significant lesions. The patient was transferred to the cardiology unit of our hospital. Based on the contained increase of the cardiac enzymes, the absence of coronary lesions, and the presence of typical echocardiography alterations, we suspected a Tako-tsubo-like syndrome. On deeper anamnestic investigation, an event of strong emotional stress emerged preceding the hospital admission that confirmed the pathology, even though it is atypical to see clinical presentation a long time after a stressful event.

Personal mastery is associated with reduced sympathetic arousal in stressed Alzheimer caregivers

OBJECTIVES

Spousal caregivers of Alzheimer's disease patients are at increased risk for cardiovascular disease, possibly via sympathetic response to stressors and subsequent catecholamine surge. Personal mastery (i.e., belief that one can manage life's obstacles) may decrease psychological and physiological response to stressors. This study examines the relationship between mastery and sympathetic arousal in elderly caregivers, as measured by norepinephrine (NE) reactivity to an acute psychological stressor.

DESIGN

Cross-sectional.

SETTING

Data were collected by a research nurse in each caregiver's home.

PARTICIPANTS

Sixty-nine elderly spousal Alzheimer caregivers (mean age: 72.8 years) who were not taking beta-blocking medication.

INTERVENTION

After assessment for mastery and objective caregiving stressors, caregivers underwent an experimental speech task designed to induce sympathetic arousal.

MEASUREMENTS

Mastery was assessed using Pearlin's Personal Mastery scale and Alzheimer patient functioning was assessed using the Clinical Dementia Rating Scale, Problem Behaviors Scale, and Activities of Daily Living Scale. Plasma NE assays were conducted using pre- and postspeech blood draws.

RESULTS

Multiple regression analyses revealed that mastery was significantly and negatively associated with NE reactivity (B = -9.86, t (61) = -2.03, p = 0.046) independent of factors theoretically and empirically linked to NE reactivity.

CONCLUSIONS

Caregivers with higher mastery had less NE reactivity to the stressor task. Mastery may exert a protective influence that mitigates the physiological effects of acute stress, and may be an important target for psychosocial interventions in order to reduce sympathetic arousal and cardiovascular stress among dementia caregivers.

Transient left ventricular dysfunction: special form of stress cardiomyopathy

A súlyos stressz hatására bekövetkező bal kamrai diszfunkció régóta ismert jelenség. Ennek a bal kamra apicalis dilatatiójával járó reverzíbilis formáját Sato és munkatársai 1990-ben történt első leírása nyomán „tako-tsubo”-cardiomyopathiának vagy ampulla-cardiomyopathiának hívják. Az erről szóló publikációkban mind a japán, mind az angolszász irodalomban szinte egyenlőségjelet tesznek a stressz-cardiomyopathia és a tako-tsubo-cardiomyopthia közé. Célkitűzés: A stressz indukálta reverzíbilis balkamra-diszfunkciós betegeink adatainak feldolgozásával tisztázni e kórkép lehetséges klinikai formáit és legjellemzőbb klinikai paramétereiket. Módszer: a 2002 és 2007 közötti, a Budai Irgalmasrendi Kórházban kezelt olyan betegek adatainak retrospektív feldolgozása, akiknél kimutatható volt a reverzíbilis balkamra-diszfunkció, és a koronarográfia negatív eredményt adott, valamint a klinikum és a laborparaméterek nem utaltak myocarditisre. Eredmények: Az elmúlt öt és fél évben összesen 6 olyan esetet találtunk, amelyek megfeleltek a fent leírt kritériumoknak. A betegek 55–80 év közötti nők voltak, akiknél öt esetben volt kimutatható oki tényezője a reverzíbilis balkamra-diszfunkciónak. Következtetések: A stressz indukálta cardiomyopathiának csak egyik formája a bal kamra csúcsi dilatációja, és ennek a csoportnak a fő közös jellemzője nem a tako-tsubo-szerű balkamra-tágulat, amely nincsen mindig jelen, hanem a szinte mindig meglévő QT-megnyúlás és negatív T-hullámok, amelyek a coronariabetegség nélküli akut, reverzíbilis balkamra-diszfunkciót néhány nappal követik megfigyeléseink és az irodalmi adatok alapján.

Cardiovascular responses to cognitive stress in patients with migraine and tension-type headache

BACKGROUND

The purpose of this study was to investigate the temporal relationship between autonomic changes and pain activation in migraine and tension-type headache induced by stress in a model relevant for everyday office-work.

METHODS

We measured pain, blood pressure (BP), heart rate (HR) and skin blood flow (BF) during and after controlled low-grade cognitive stress in 22 migraineurs during headache-free periods, 18 patients with tension-type headache (TTH) and 44 healthy controls. The stress lasted for one hour and was followed by 30 minutes of relaxation.

RESULTS

Cardiovascular responses to cognitive stress in migraine did not differ from those in control subjects. In TTH patients HR was maintained during stress, whereas it decreased for migraineurs and controls. A trend towards a delayed systolic BP response during stress was also observed in TTH. Finger BF recovery was delayed after stress and stress-induced pain was associated with less vasoconstriction in TTH during recovery.

CONCLUSION

It is hypothesized that TTH patients have different stress adaptive mechanisms than controls and migraineurs, involving delayed cardiovascular adaptation and reduced pain control system inhibition.

Developmental origins of obesity: a sympathoadrenal perspective

Environmental exposures at crucial points in development permanently alter sympathoadrenal function in mammals. Both the sympathetic innervation of peripheral tissues and the responsiveness of sympathetic nerves and adrenal medulla to standard stimuli are susceptible to modification by exposures in early life. Several conditions studied in the laboratory, including environmental temperature, litter size and maternal nutrition, in addition to affecting sympathoadrenal function also produce larger, fatter offspring, raising the possibility that developmental programming of the sympathetic nervous system (SNS) may contribute to acquisition of an obese phenotype. The specific changes noted in all three circumstances include evidence of an increase in sympathetic innervation in pancreas and retroperitoneal fat. By contrast, SNS development is impaired in experimental models of intrauterine growth retardation. Although the physiological implications of increased sympathetic innervation in pancreas and retroperitoneal fat are not fully understood, these changes seen in animals reared at cool temperatures, in small litters or by mothers fed refined carbohydrate diets likely reflect an early enhancement of the offspring's capacity to take up and store glucose. If so, the tendency of these animals to gain weight and accumulate fat may represent an adaptive response to 'over-nutrition' in early life.

Age and sex as determinants of ventricular arrhythmic events in patients with decompensated congestive heart failure

BACKGROUND

The propensity to develop specific arrhythmias varies between the sexes and is influenced by age. Patients with congestive heart failure (CHF) have a high prevalence of ventricular ectopy. However, in the setting of CHF, it is not known whether sex-related or age-dependent differences exist in the susceptibility to arrhythmias.

METHODS

The study population included 134 men and 73 women (mean age 61 +/- 14 years) admitted for decompensated CHF. The severity of ventricular arrhythmias was assessed by 24-hour Holter monitoring. None of the patients were on parenteral vasoactive therapy during Holter recording.

RESULTS

All measures of ventricular ectopy were markedly lower in women. The average hourly premature ventricular contractions (PVCs), the frequency of ventricular pairs, the mean hourly repetitive ventricular beats, and the frequency of ventricular tachycardia episodes per 24 hours were 40%, 62%, 65%, and 78% lower in women, respectively. Multivariate logistic regression revealed that the risk of developing > 3 ventricular pairs per 24-hour period (OR = 2.2, CI = 1.1-4.2, P = 0.03), > 3 repetitive ventricular beats/hour (OR = 2.5, CI = 1.2-5.3, P = 0.01), or an episode of ventricular tachycardia (OR = 2.1, CI = 1.2-3.9, P = 0.01) were significantly higher in men. Patients in the higher tertile age group had a higher risk for the presence of > 3 ventricular pairs per 24-hour period (OR = 2.3, CI = 1.1-4.2, P = 0.03), and the presence of > 3 repetitive ventricular beats per hour (OR = 5.9, CI = 2.7-13.3, P < 0.0001), compared with patients in the lower age tertile.

CONCLUSION

Male sex and age are associated with complex ventricular ectopy in patients with CHF. Further understanding of the mechanisms involved in the relative protection conferred by female sex would advance our understanding about arrhythmias in heart failure.

Establishment and Application of Enzyme Immunoassay for Saliva Cortisol in Taiwanese Context

Saliva steroid assay is an upcoming area of research, with much potential for growth and progress. Expensive, varying results with commercial kits and the disadvantages of radioimmunoassay have forced researchers to develop their own system of enzyme immunoassay (EIA). A modification from our established EIA system was used to develop a saliva cortisol (F) assay system. The system sensitivity (>90pg/mL) was checked by various experiments, including comparison of data with a commercial kit obtained from Salimetrics. The assay system was employed to investigate the saliva F level in a young Taiwanese population, and compared with the total and free serum levels of F.

Effect of a high-fat meal on the growth hormone response to exercise in children

Exercise-induced growth hormone (GH) secretion may significantly modulate growth and development in children. Altered physiological GH responses, therefore, may reduce the beneficial effects of exercise. High-fat food ingestion before exercise blunts the GH response in adults, but it is unknown whether this occurs in children. We therefore performed standard exercise tests, following a high-fat meal or placebo, in 12 children, age 11-15 (6 M, 6 F). GH, insulin-like growth factor-I, glucose, insulin, glucagon, cortisol, epinephrine and interleukin-6 samples were drawn at baseline, end-exercise, and 30 and 60 min post-exercise. While GH was similar at baseline in all experiments, the exercise-induced GH peak was lower after the high-fat meal (6.7 +/- 1.6 ng/l vs 11.8 +/- 2.4 ng/l, p <0.02). Other exercise responses were not affected by prior fat ingestion. A high-fat meal before exercise, therefore (a common event in Western societies), may reduce the growth factor response to exercise in children, with potential implications for growth and development.

Neurohumoral features of myocardial stunning due to sudden emotional stress

BACKGROUND

Reversible left ventricular dysfunction precipitated by emotional stress has been reported, but the mechanism remains unknown.

METHODS

We evaluated 19 patients who presented with left ventricular dysfunction after sudden emotional stress. All patients underwent coronary angiography and serial echocardiography; five underwent endomyocardial biopsy. Plasma catecholamine levels in 13 patients with stress-related myocardial dysfunction were compared with those in 7 patients with Killip class III myocardial infarction.

RESULTS

The median age of patients with stress-induced cardiomyopathy was 63 years, and 95 percent were women. Clinical presentations included chest pain, pulmonary edema, and cardiogenic shock. Diffuse T-wave inversion and a prolonged QT interval occurred in most patients. Seventeen patients had mildly elevated serum troponin I levels, but only 1 of 19 had angiographic evidence of clinically significant coronary disease. Severe left ventricular dysfunction was present on admission (median ejection fraction, 0.20; interquartile range, 0.15 to 0.30) and rapidly resolved in all patients (ejection fraction at two to four weeks, 0.60; interquartile range, 0.55 to 0.65; P<0.001). Endomyocardial biopsy showed mononuclear infiltrates and contraction-band necrosis. Plasma catecholamine levels at presentation were markedly higher among patients with stress-induced cardiomyopathy than among those with Killip class III myocardial infarction (median epinephrine level, 1264 pg per milliliter [interquartile range, 916 to 1374] vs. 376 pg per milliliter [interquartile range, 275 to 476]; norepinephrine level, 2284 pg per milliliter [interquartile range, 1709 to 2910] vs. 1100 pg per milliliter [interquartile range, 914 to 1320]; and dopamine level, 111 pg per milliliter [interquartile range, 106 to 146] vs. 61 pg per milliliter [interquartile range, 46 to 77]; P<0.005 for all comparisons).

CONCLUSIONS

Emotional stress can precipitate severe, reversible left ventricular dysfunction in patients without coronary disease. Exaggerated sympathetic stimulation is probably central to the cause of this syndrome.

Sex-based differences in gastrointestinal pain

Recent interest has focused on sex-related differences in irritable bowel syndrome (IBS) physiology and treatment responsiveness to novel pharmacologic therapies. Similar to a variety of other chronic pain conditions and certain affective disorders, IBS is more prevalent amongst women, both in population-based studies as well as in clinic-based surveys. Non-painful gastrointestinal symptoms, constipation and somatic discomfort are more commonly reported by female IBS patients. While perceptual differences to rectosigmoid stimulation are only observed following repeated noxious stimulation of the gut, sex-related differences in certain sympathetic nervous system (SNS) responses to rectosigmoid stimulation are consistently seen. Consistent with experimental findings in animals, current evidence is consistent with a pathophysiological model which emphasizes sex-related differences in autonomic and antinociceptive responses to certain visceral stimuli.

Consistency in physiological stress responses and electromyographic activity during induced stress exposure in women and men

Physiological responses serve the role as objective indicators of stress as well as a link between psychosocial stress and various health outcomes. The aim of the present exposure session was to compare different physiological stress responses (systolic and diastolic blood pressure, heart rate, urinary epinephrine and norepinephrine, salivary cortisol) as well as trapezius muscle activity, measured by surface electromyography, during mental and physical stress in 11 women and ten men. The results show significantly increased activity in all measures but cortisol and significant associations between sympathetic arousal and EMG activity. The association between sympathetic arousal and muscle activity is of importance for understanding the high prevalence of musculoskeletal disorders in mentally stressful but physically light work tasks. Men had higher blood pressure and a more pronounced increase in epinephrine output than women, whereas women had higher heart rate. It was concluded that sympathetic activity is more sensitive to moderately intense stress exposure than pituitary adrenocortical (cortisol) activity and that men respond to performance stress with more epinephrine output than women. Although the correlations between the different indicators of sympathetic arousal were high, together they could still only explain 30-70% of the inter-individual variance. Thus, several parameters are needed in order to obtain a reliable measure of sympathetic activity.