Assessment of stress markers in restrained individuals following physical stress with and without sham CED activation.

INTRODUCTION: Law enforcement and pre-hospital care personnel often confront individuals who must be physically restrained. Many are under the influence of illicit substances, and law enforcement officers may need to use a controlled electrical device (CED) to gain control of the individual and they are often placed into the prone maximum restraint (PMR) position. These techniques have previously been evaluated for their physiologic effects. The purpose of this study was to investigate the psychological effects of anticipating and experiencing a sham CED activation in healthy human subjects who were exercised and restrained compared with no sham activation by assessing the differences in a panel of several known biomarkers of stress. METHODS: We performed a randomized, crossover controlled human subject trial to study the stress associated with exercise, physical exhaustion, and restraint with and without an added psychological stress simulating the field use of a CED. Twenty five total subjects; each subject performed two different trials each consisting of a brief period of intense exercise on a treadmill to exhaustion followed by placement in the PMR with and without induced psychological stress. Blood samples were collected for analysis pre and post exercise, as well as 10 min after completion of the exercise. A panel of hormones and stress markers were measured. RESULTS: We found no significant differences in any of the stress biomarkers measured between the two study groups. A trend towards higher levels of copeptin was measured in the sham CED activation arm. CONCLUSION: During a brief period of intense exercise followed by the psychological stress of anticipated CED application, there did not appear to be statistically significant changes in the stress panel of biomarkers measured, only a trend towards significance for higher copeptin levels in the patients exposed to the psychological stress.

Physical performance, demographic, psychological, and physiological predictors of success in the U.S. Army Special Forces Assessment and Selection course.

This study assessed predictors of successful selection in the very challenging and stressful United States Army Special Forces Assessment and Selection (SFAS) course among 800 Soldiers. A battery of measures were collected during the course and their ability to predict selection were assessed using logistic regression and chi-square tests. Physical performance measures were most predictive, including road march times, land navigation coordinates found, run times, fitness test score, obstacle course score, and pull-ups (p < .05). Soldiers that were officers or 18× enlisted (fast-tracked to SFAS), had <1 year of active duty, ≥ bachelor degree, no children, were not married, and were Ranger school graduates were more likely to be selected (p < .05). Several psychological measures were predictive, including intelligence quotient, grade level equivalents, resilience score, military aptitude score, and grit (p < .05). Basal serum physiological markers weakly predicted selection and were weakly associated with behavioral assessments. Lower C-reactive protein (< 9.5 nmol/L) and higher cortisol and sex-hormone binding globulin (SHBG) predicted selection (p < .05). Higher C-reactive protein (≥ 9.5 nmol/L) was associated with lower fitness test scores and slower road march time (p < .05). Cortisol was correlated with higher grit and resilience scores (p < .05). SHBG correlated with higher grade level equivalents and better performance on pull-ups, land navigation, obstacle course, and the fitness test (p < .05). Testosterone was correlated with faster run and road march times (p < .05). Dehydroepiandrosterone-sulfate (DHEA-S) correlated with lower resilience scores, and DHEA-S, epinephrine, and norepinephrine correlated with worse performance on several physical events (p < .05). These findings suggest measures that could be targeted in interventions to monitor and enhance performance and resilience.

Cardiovascular magnetic resonance assessment of acute cardiovascular effects of voluntary apnoea in elite divers.

BACKGROUND: Prolonged breath holding results in hypoxemia and hypercapnia. Compensatory mechanisms help maintain adequate oxygen supply to hypoxia sensitive organs, but burden the cardiovascular system. The aim was to investigate human compensatory mechanisms and their effects on the cardiovascular system with regard to cardiac function and morphology, blood flow redistribution, serum biomarkers of the adrenergic system and myocardial injury markers following prolonged apnoea. METHODS: Seventeen elite apnoea divers performed maximal breath-hold during cardiovascular magnetic resonance imaging (CMR). Two breath-hold sessions were performed to assess (1) cardiac function, myocardial tissue properties and (2) blood flow. In between CMR sessions, a head MRI was performed for the assessment of signs of silent brain ischemia. Urine and blood samples were analysed prior to and up to 4 h after the first breath-hold. RESULTS: Mean breath-hold time was 297 ± 52 s. Left ventricular (LV) end-systolic, end-diastolic, and stroke volume increased significantly (p < 0.05). Peripheral oxygen saturation, LV ejection fraction, LV fractional shortening, and heart rate decreased significantly (p < 0.05). Blood distribution was diverted to cerebral regions with no significant changes in the descending aorta. Catecholamine levels, high-sensitivity cardiac troponin, and NT-pro-BNP levels increased significantly, but did not reach pathological levels. CONCLUSION: Compensatory effects of prolonged apnoea substantially burden the cardiovascular system. CMR tissue characterisation did not reveal acute myocardial injury, indicating that the resulting cardiovascular stress does not exceed compensatory physiological limits in healthy subjects. However, these compensatory mechanisms could overly tax those limits in subjects with pre-existing cardiac disease. For divers interested in competetive apnoea diving, a comprehensive medical exam with a special focus on the cardiovascular system may be warranted. TRIAL REGISTRATION: This prospective single-centre study was approved by the institutional ethics committee review board. It was retrospectively registered under ClinicalTrials.gov (Trial registration: NCT02280226 . Registered 29 October 2014).

Choosing the optimal method of anaesthesia in anterior resection of the rectum procedures - assessment of the stress reaction based on selected hormonal parameters.

INTRODUCTION: The aim of this study was to compare hormonal stress responses (changes in adrenaline, noradrenaline, and cortisol concentrations) to surgical injury during total intravenous propofol anaesthesia and volatile anaesthesia with sevoflurane in patients subjected to anterior resection of the rectum. MATERIAL AND METHODS: The prospective randomised study included 61 patients qualified for anterior resection of the rectum. The subjects were randomised into two groups, based on the type of anaesthesia: 1) Group I (TIVA, n = 31), administered total intravenous propofol anaesthesia, and 2) Group II (VIMA, n = 30), administered volatile induction and maintenance sevoflurane anaesthesia. Serum concentra-tions of adrenaline, noradrenaline, and cortisol were determined prior to surgery, during assessment of abdominal cavity, after resection of the rectum, and 30 min and one day post-surgery. RESULTS: The two groups did not differ significantly in terms of their haemodynamic parameters: heart rate and arterial blood pressure. Compared to individuals subjected to TIVA, patients from the VIMA group presented with significantly higher concentrations of adrenaline during evaluation of the abdominal organs. No significant intergroup differences were found in terms of intra- and postoperative serum concentrations of noradrenaline and cortisol. CONCLUSIONS: TIVA and VIMA induce similar hormonal stress responses during anterior resection of the rectum. The increase in serum adrenaline concentration during evaluation of the abdominal organs in the VIMA group implies that the dose of sevoflurane should be escalated at this time point.

Resting sympathetic activity is associated with the sympathetically mediated component of energy expenditure following a meal.

Individuals with high plasma norepinephrine (NE) levels at rest have a smaller reduction in resting energy expenditure (REE) following ß-adrenergic blockade. If this finding extends to the response to a meal, it could have important implications for the role of the sympathetic nervous system in energy balance and weight gain. We hypothesized high muscle sympathetic nerve activity (MSNA) would be associated with a low sympathetically mediated component of energy expenditure following a meal. Fourteen young, healthy adults completed two visits randomized to continuous saline (control) or intravenous propranolol to achieve systemic ß-adrenergic blockade. Muscle sympathetic nerve activity and REE were measured (indirect calorimetry) followed by a liquid mixed meal (Ensure). Measures of energy expenditure continued every 30 min for 5 h after the meal and are reported as an area under the curve (AUC). Sympathetic support of energy expenditure was calculated as the difference between the AUC during saline and ß-blockade (AUCPropranolol-AUCSaline, ß-REE) and as a percent (%) of control (AUCPropranolol÷AUCSaline × 100). ß-REE was associated with baseline sympathetic activity, such that individuals with high resting MSNA (bursts/100 heart beats) and plasma NE had the greatest sympathetically mediated component of energy expenditure following a meal (MSNA: ß-REE R = -0.58, P = 0.03; %REE R = -0.56, P = 0.04; NE: ß-REE R = -0.55, P = 0.0535; %REE R = -0.54, P = 0.0552). Contrary to our hypothesis, high resting sympathetic activity is associated with a greater sympathetically mediated component of energy expenditure following a liquid meal. These findings may have implications for weight maintenance in individuals with varying resting sympathetic activity.

Optimization of pressure settings during adaptive servo-ventilation support using real-time heart rate variability assessment: initial case report.

BACKGROUND: Adaptive servo-ventilation (ASV) therapy is a recent non-invasive positive pressure ventilation therapy that was developed for patients with heart failure (HF) refractory to optimal medical therapy. However, it is likely that ASV therapy at relatively higher pressure setting worsens some of the patients' prognosis compared with optimal medical therapy. Therefore, identification of optimal pressure settings of ASV therapy is warranted. CASE PRESENTATION: We present the case of a 42-year-old male with HF, which was caused by dilated cardiomyopathy, who was admitted to our institution for evaluating his eligibility for heart transplantation. To identify the optimal pressure setting [peak end-expiratory pressure (PEEP) ramp test], we performed an ASV support test, during which the PEEP settings were set at levels ranging from 4 to 8 mmHg, and a heart rate variability (HRV) analysis using the MemCalc power spectral density method. Clinical parameters varied dramatically during the PEEP ramp test. Over incremental PEEP levels, pulmonary capillary wedge pressure, cardiac index and high-frequency level (reflecting parasympathetic activity) decreased; however, the low-frequency level increased along with increase in plasma noradrenaline concentrations. CONCLUSIONS: An inappropriately high PEEP setting may stimulate sympathetic nerve activity accompanied by decreased cardiac output. This was the first report on the PEEP ramp test during ASV therapy. Further research is warranted to determine whether use of optimal pressure settings using HRV analyses may improve the long-term prognosis of such patients.

Assessment of vascular autonomic function using peripheral arterial tonometry.

Peripheral autonomic function is impaired in diabetic polyneuropathy. However, it is difficult to evaluate it due to the lack of non-invasive quantitative assessment. We aimed to establish a novel index to evaluate vascular autonomic function using reactive hyperemia peripheral arterial tonometry (RH-PAT), a widely performed endothelial function test. Sixty-five subjects were enrolled, including healthy subjects, cases with sympathetic nerve blockers, and diabetic patients. RH-PAT was performed with 5-min blood flow occlusion in unilateral arm. We calculated the reduction ratio of the post-occlusion pulse amplitude to the baseline in the non-occluded arm (RPN), with 1-min sliding window. In healthy subjects, RPN gradually increased with time-dependent manner. However, this phenomenon was eliminated in cases with sympathetic nerve blockers. Plasma concentration of norepinephrine was measured before and after the blood flow occlusion, which showed a significant increase. We then compared RPNs with the change in heart rate variability (HRV) parameters. RPN calculated at 5 min after the reperfusion had the highest correlation with the change in sympathetic HRV parameter, and thus, we named sympathetic hypoemia index (SHI). Finally, we studied the relationship between SHI and diabetes. SHI was significantly lower in diabetic patients than matched controls. SHI, a novel index derived from RH-PAT, represented the peripheral sympathetic activity. SHI may be useful for assessing the vascular autonomic activity in diabetic patients.

Assessment of respiratory disturbance index determined with a non-restrictive monitor and of autonomic nervous system parameters in heart failure patients: A pilot study.

BACKGROUND: There is a link between sympathetic overactivity and sleep-disordered breathing (SDB), and both of which are important indicators of the development of heart failure. To manage the increasing numbers of heart failure patients, any method used to check for them needs to be as non-invasive, simple, and cost-effective as possible. The purpose of this study is to assess screening of SDB with a non-restrictive monitor and the autonomic nervous system in heart failure patients. METHODS: The subjects were 49 patients (mean age: 67 years; male: 78%) hospitalized for worsening heart failure. After stabilization with appropriate medical therapy, each patient simultaneously underwent sleep apnea syndrome (SAS) screening with the SD-101 (Kenzmedico Co. Ltd., Saitama, Japan), which is a novel, non-restrictive, sheet-like monitor for SAS screening, and assessment of heart rate variability (HRV) with a Holter monitor. In addition, we assessed daytime sleepiness by using the Epworth Sleepiness Scale. RESULTS: The mean respiratory disturbance index (RDI) was 21.9 events/h. Males had significantly greater RDI values than females (24.5±11.2 events/h vs. 13.0±6.2 events/h, p<0.001). RDI on SD-101 testing was closely correlated with cyclic variation of heart rate index obtained with a Holter electrocardiogram scanner (r=0.843). Although plasma brain natriuretic peptide level was not correlated with HRV, plasma norepinephrine level was moderately well correlated with the total low- to high-frequency ratio of HRV (r=0.529). CONCLUSIONS: SAS screening is important for heart failure patients, because absence of subjective sleepiness is not reliable in ruling out SDB. The SAS screening with SD-101 might apply for managing heart failure.

Energy expenditure, spontaneous physical activity and with weight gain in kidney transplant recipients.

BACKGROUND & AIMS: Alterations in energy metabolism could trigger weight gain after renal transplantation. METHODS: Nineteen transplanted non-diabetic men, 53 ± 1.6 years old, receiving calcineurin inhibitors but no corticosteroids were studied. They were compared with nine healthy men matched for height, age and lean body mass. Daily energy expenditure and its components (sleeping, basal and absorptive metabolic rates) were analyzed for 24 h in calorimetric chambers and for 4 days in free living conditions using calibrated accelerometry. Other variables known to influence energy expenditure were assessed: body composition, physical activity, 4-day food intake, drug consumption, serum C-reactive protein, interleukin-6, thyroid and parathyroid hormones, and epinephrine. Transplant recipients who gained more than 5% body weight after transplantation (n = 11, +11.0 ± 1.5 kg) were compared with those who did not (n = 8) and with the controls. RESULTS: Weight gain compared with non-weight gain patients and controls exhibited higher fat mass without change in lean body mass. Daily, sleeping and resting energy expenditure adjusted for lean body mass was significantly higher in non-weight gain (167.1 ± 4.2 kJ/kg/lean body mass/24 h, P < 0.05) compared with weight gain patients (147.4 ± 3.6) and controls (146.1 ± 4.6). Weight gain compared with controls and non-weight gain subjects had lower free living physical activity and a higher consumption of antihypertensive drugs and ß-blockers. CONCLUSIONS: After kidney transplantation, weight gain patients were characterized by lower adjusted energy expenditure, reduced spontaneous physical activity but a more sedentary life style and a trend toward a higher energy intake explaining the reason they gained weight. The nWG KTR had increased resting and sleeping EE which protected them from weight gain. Such hypermetabolism was also observed in 24-h EE measurements. By comparison with the nWG patients, the WG transplant recipients were characterized by higher ß-blocker consumption. These data could be helpful in the prevention of weight gain in kidney transplant recipients.

[Assessment of the perioperative factors contributing to the hemodynamic changes during surgery in ten patients with pheochromocytoma].

BACKGROUND: Intensive perioperative management is required for adrenalectomy in patients with pheocromocytoma because of the unstable hemodynamics and life threatening cardiovascular disturbances due to catecholamine surge from the neuroendocrine tumors. The aim of this study was to assess the perioperative factors contributing to the hemodynamic changes during surgery in pheochromocytoma. METHODS: Ten patients with pheochromocytoma undergoing elective adrenalectomy were enrolled in this retrospective study. The circulating blood volume before surgery and the perioperative factors associated with hemodynamic changes during surgery were assessd by the pulse dye densitometry and VigileoTM/ FroTracTM system, respectively. RESULTS: The decreases of blood pressure after resections of the central veins from tumors were significantly greater in laparotomy than those in laparoscopic surgery (P<0.05). In addition, the decreases of blood pressure after resection of the central were correlated with tumor sizes (R= -0.611), perioperative noradrenaline (NA) blood levels (R= -0.860), perioperative amounts of NA in urine (R= -0.743), and mean stroke volume variations for 5 min after resection of the veins(R= - 0.679). CONCLUSIONS: The decreases of blood pressure after resections of the central veins are dependent on the perioperative blood NA levels, the level of NA in the perioperative urine testig, and tumor sizes.

Sympathetic support of energy expenditure and sympathetic nervous system activity after gastric bypass surgery.

OBJECTIVE: This study was designed to determine how gastric bypass affects the sympathetically-mediated component of resting energy expenditure (REE) and muscle sympathetic nerve activity (MSNA). DESIGN AND METHODS: We measured REE before and after beta-blockade in seventeen female subjects approximately three years post-gastric bypass surgery and in nineteen female obese individuals for comparison. We also measured MSNA in a subset of these subjects. RESULTS: The gastric bypass subjects had no change in REE after systemic beta-blockade, reflecting a lack of sympathetic support of REE, in contrast to obese subjects where REE was reduced by beta-blockade by approximately 5% (P < 0.05). The gastric bypass subjects, while still overweight (BMI = 29.3 vs 38.0 kg·m(-2) for obese subjects, P < 0.05), also had significantly lower MSNA compared to obese subjects (10.9 ± 2.3 vs. 21.9 ± 4.1 bursts·min(-1) , P < 0.05). The reasons for low MSNA and a lack of sympathetically mediated support of REE after gastric bypass are likely multifactorial and may be related to changes in insulin sensitivity, body composition, and leptin, among other factors. CONCLUSIONS: These findings may have important consequences for the maintenance of weight loss after gastric bypass. Longitudinal studies are needed to further explore the changes in sympathetic support of REE and if changes in MSNA or tissue responsiveness are related to the sympathetic support of REE.

Plasma leptin and energy expenditure during prolonged, moderate intensity, treadmill exercise.

BACKGROUND: Current literature shows conflicting results regarding the possible direct role of exercise on leptin concentrations, mainly because of a non-homogeneous level of energy expenditure (EE) and the lack of standardization of energy balance. AIM: The aim of the study was to evaluate the effect of exercise duration and its corresponding EE on leptin levels, during prolonged treadmill exercise, in a well-controlled laboratory setting. MATERIALS AND METHODS: Seven young trained males underwent a 4-h treadmill exercise. The starting intensity was set at 65% of maximal oxygen consumption. At the start of the test and throughout the exercise, venous blood samples were drawn for the assays of leptin, glucose, free fatty acids (FFA), cortisol, epinephrine (E) and norepinephrine (NE). Hourly and total EE was monitored with gas analysis. RESULTS: Plasma leptin levels decreased from 1.10±0.15 to 0.85±0.26 µg/l (p<0.01) at the end of the exercise, reaching a significant reduction already after the second hour. FFA and cortisol showed a progressive significant increase, while glucose did not significantly change throughout the test. Plasma E and NE significantly increased at all sampling times compared to basal values (48.1±30.3 to 352.3±187.7 pg/ml, p<0.001 and 238.1±118.9 to 1798.7±413.5 pg/ml, p<0.001). The random-effects model for panel data analysis showed negative correlation between leptin, NE and the values of progressive EE (r2=0.745, p<0.05). CONCLUSIONS: Our data demonstrate that, during a prolonged moderate intensity exercise, leptin decrease is significantly related to the total EE. Further, NE concentrations seem to play an important role in the inhibition of leptin secretion.

Relationship between psychological stress and reproductive outcome in women undergoing in vitro fertilization treatment: psychological and neurohormonal assessment.

PURPOSE: To evaluate whether psychological stress, as well as changes in hypothalamus-pituitary-adrenal (HPA) axis and sympathetic nervous system (SNS) at different time points during a first in vitro fertilization (IVF) cycle, correlates with the reproductive outcome. METHODS: A prospective study was conducted in 264 women undergoing IVF or intracytoplasmic sperm injection (ICSI) treatment between January 2009 and March 2010. Standardized psychological questionnaires were used to assess anxiety and depression. Norepinephrine and cortisol in serum were measured with specific assays. RESULTS: The non-pregnant women reported higher anxiety and depression scores at the pregnancy detection day compared with the pregnant group. Lower levels of norepinephrine and cortisol at the time of oocyte retrieval and lower levels of cortisol at the time of pregnancy test were found in women with successful treatment. Significant increases in serum norepinephrine and cortisol values were observed during ovarian stimulation. State Anxiety scores were negatively correlated with live birth rate, and positively associated with serum norepinephrine and cortisol values. CONCLUSIONS: State anxiety is associated with both pregnancy rate and live birth rate in IVF patients, an effect that is partly mediated by activities in the HPA and SNS.

Neuroendocrine assessment of serotonergic, dopaminergic, and noradrenergic functions in alcohol-dependent individuals.

BACKGROUND: Alcohol dependence has been associated with reduced function of serotonin, dopamine as well as noradrenaline activities in several neuroendocrine studies. To our knowledge, there is, however, no study investigating all these 3 systems with the use of neuroendocrine methods in one and the same alcohol-dependent individual. METHODS: Alcohol-dependent individuals (n = 42) and controls (n = 28) participated in the neuroendocrine test series. Central serotonergic neurotransmission was assessed by the prolactin (PRL) response to citalopram (CIT). The postsynaptic DRD2 function was measured by the growth hormone (GH) response to apomorphine (APO) and the postsynaptic α2-adrenoceptor function by GH response to clonidine (CLON). RESULTS: In the alcohol-dependent individuals, the PRL concentrations were significantly lower at the time points 240 minutes and 300 minutes after CIT administration and mean delta PRL value was significantly reduced by 45% in comparison with controls. There were no significant differences in APO-GH and CLON-GH concentrations at any time points or in mean delta GH values between the groups. An impaired monoaminergic profile, including all 3 systems, was significantly more frequent in alcohol-dependent individuals than controls (43% vs. 6% respectively). CONCLUSIONS: The monoaminergic dysfunction was restricted to an impairment of the serotonergic system, suggesting that this system is especially vulnerable to long-term and excessive alcohol consumption. Moreover, impaired monoaminergic profiles, including low responses in 2 or 3 systems, were more frequently observed in alcohol-dependent individuals than in controls. Such impaired profiles may be of clinical importance, but further studies are needed.

Acute sleep deprivation reduces energy expenditure in healthy men.

BACKGROUND: Epidemiologic evidence indicates that chronic sleep curtailment increases risk of developing obesity, but the mechanisms behind this relation are largely unknown. OBJECTIVE: We examined the influence of a single night of total sleep deprivation on morning energy expenditures and food intakes in healthy humans. DESIGN: According to a balanced crossover design, we examined 14 normal-weight male subjects on 2 occasions during a regular 24-h sleep-wake cycle (including 8 h of nocturnal sleep) and a 24-h period of continuous wakefulness. On the morning after regular sleep and total sleep deprivation, resting and postprandial energy expenditures were assessed by indirect calorimetry, and the free-choice food intake from an opulent buffet was tested in the late afternoon at the end of the experiment. Circulating concentrations of ghrelin, leptin, norepinephrine, cortisol, thyreotropin, glucose, and insulin were repeatedly measured over the entire 24-h session. RESULTS: In comparison with normal sleep, resting and postprandial energy expenditures assessed on the subsequent morning were significantly reduced after sleep deprivation by ≈5% and 20%, respectively (P < 0.05 and P < 0.0001). Nocturnal wakefulness increased morning plasma ghrelin concentrations (P < 0.02) and nocturnal and daytime circulating concentrations of thyreotropin, cortisol, and norepinephrine (P < 0.05) as well as morning postprandial plasma glucose concentrations (P < 0.05). Changes in food intakes were variable, and no differences between wake and sleep conditions were detected. CONCLUSION: Our findings show that one night of sleep deprivation acutely reduces energy expenditure in healthy men, which suggests that sleep contributes to the acute regulation of daytime energy expenditure in humans.

Effects of Alzheimer caregiving on allostatic load.

This study aimed to determine if Alzheimer caregivers have increased allostatic load compared to non-caregivers. Potential psychological moderators (mastery, depression, and role overload) of the relationship between caregiving status and allostatic load were also explored. Eighty-seven caregivers and 43 non-caregivers underwent biological assessment of allostatic load and psychological assessments. Caregivers had significantly higher allostatic load compared to non-caregivers ( p < .05). Mastery, but not depression or overload, moderated the relationship between caregiving status and allostatic load. In conclusion, allostatic load may represent a link explaining how stress translates to downstream pathology, but more work is necessary to understand the role of psychological factors.

Noninvasive assessment of autonomic activity for evaluation of pain in calves, using surgical castration as a model.

The role of the autonomic nervous system (ANS) in mediating eye temperature responses during painful procedures was examined in thirty 4-mo-old bull calves randomly assigned to 4 treatments: 1) sham handling control (C; n=8), 2) surgical castration (SC; n=6), 3) local anesthesia with sham handling (LAC; n=8), and 4) local anesthesia with surgical castration (LASC; n=8). Maximum eye temperature ( degrees C), measured by infrared thermography, heart rate (HR), and heart rate variability (HRV) were recorded continuously from 25 min before to 20 min after castration. The HRV was analyzed by examining segments of 512 interbeat intervals before and after treatments and comparing the root mean square of successive differences (RMSSD), high and low frequency (HF and LF, respectively) power, and the ratio of LF and HF powers (LF:HF). Jugular blood samples were analyzed for norepinephrine and epinephrine in C and SC treatments and for cortisol during all treatments. There was an immediate increase in HR following castration in SC (+15.3+/-2.8 beats/min) and LASC (+6.3+/-2.4 beats/min) calves. Eye temperature increased during the 20-min observation period in SC and LASC calves (+0.47+/-0.05 degrees C and +0.28+/-0.05 degrees C, respectively), and there was a small increase in C calves (+0.10+/-0.05 degrees C). Following castration in SC calves, there was an increase in RMSSD (+25.8+/-6.4) and HF power (+11.0+/-6.5) and LF:HF decreased (-2.1+/-0.7). Following castration in LASC, there was an increase in RMSSD (+18.1+/-4.9) and a decrease in LF power (-10.2+/-5.0). Cortisol increased above baseline within 15 min following treatment in both castrated groups, but was greater for SC calves (+18.4+/-2.3 ng/mL) than for LASC calves (+11.1+/-1.9 ng/mL). After castration, norepinephrine increased 3-fold and epinephrine increased by half in SC calves but not in C calves. There were no changes in HR, HRV, or cortisol responses to C or LAC treatments. Local anesthetic reduced, but did not eliminate, responses to surgical castration. The synchronized increase in catecholamine and HR responses immediately following SC treatment suggests the initial response was mediated by the sympathetic branch of the ANS. The subsequent changes in RMSSD, HF power, and LF:HF ratio indicated this was followed by an increase in parasympathetic activity. The use of HR, HRV, and infrared thermography measurements together provide a noninvasive means to assess ANS responses as indicators of acute pain in cattle.

Increased energy expenditure and glucose oxidation during acute nontraumatic skin pain in humans.

BACKGROUND AND OBJECTIVE: Tissue injury is accompanied by pain and results in increased energy expenditure, which may promote catabolism. The extent to which pain contributes to this sequence of events is not known. METHODS: In a cross-over design, 10 healthy volunteers were examined on three occasions; first, during self-controlled nontraumatic electrical painful stimulus to the abdominal skin, maintaining an intensity of 8 on the visual analogue scale (0-10). Next, the electrical stimulus was reproduced during local analgesia and, finally, there was a control session without stimulus. Indirect calorimetry and blood and urine sampling was done in order to calculate energy expenditure and substrate utilization. RESULTS: During pain stimulus, energy expenditure increased acutely and reversibly by 62% (95% confidence interval, 43-83), which was abolished by local analgesia. Energy expenditure paralleled both heart rate and blood catecholamine levels. The energy expenditure increase was fuelled by all energy sources, with the largest increase in glucose utilization. CONCLUSION: The pain-related increase in energy expenditure was possibly mediated by adrenergic activity and was probably to a large extent due to increased muscle tone. These effects may be enhanced by cortical events related to the pain. The increase in glucose consumption favours catabolism. Our findings emphasize the clinical importance of pain management.

Neuroendocrine biomarkers, social relations, and the cumulative costs of stress in Taiwan.

Allostatic load (AL) is thought to represent the physiological toll that builds up over the life course as a consequence of the body's response to stress. An important aim of this paper is to test this widely held-but little investigated-understanding of what AL represents. More specifically, using the Social Environment and Biomarkers of Aging Study (SEBAS), a nationally representative survey of Taiwan conducted in year 2000, this paper scrutinizes the connection between stressful life histories and neuroendocrine allostatic load (NAL). Stressful life histories are operationalized through the use of two sets of indicators: one set makes use of respondents' subjective interpretations of various life domains and the other makes use of non-subjective data about conditions that are expected to be stressful (e.g., widowhood, living alone, and low education). NAL is an index of four neuroendocrine biomarkers (cortisol, dehydroepiandrosterone sulfate (DHEAS), epinephrine, and norepinephrine) collected in blood and urine samples under resting, basal states. The major findings of this paper are twofold. First, there is little evidence to support the hypothesis that baseline levels of the neuroendocrine markers stem from stressful life histories. Second, report of current stress (among women only) is positively correlated with higher NAL levels. Taken together, these findings question whether the neuroendocrine markers of the AL construct reflect long-term processes over the life course. Indeed, evidence here suggests that the neuroendocrine markers may reflect the exact opposite-a transient state at the time of the study.

Utility of plasma apelin and other indices of cardiac dysfunction in the clinical assessment of patients with dilated cardiomyopathy.

Apelin is a recently discovered peptide ligand reported to be involved in the regulation of cardiovascular homeostasis. The exact role of apelin in the pathophysiology of congestive heart failure has remained obscure, and the reported circulating levels of apelin in patients with heart failure have been contradictory. To establish the role of apelin in the assessment of cardiac dysfunction we measured plasma apelin levels in 65 patients with congestive heart failure caused by idiopathic dilated cardiomyopathy (IDC) and 14 healthy volunteers by specific radioimmunoassay. IDC patients were carefully examined including echocardiography, both-sided cardiac catheterization and cardiopulmonary exercise test. In addition, plasma levels of N-terminal pro-brain natriuretic peptide (NT-proBNP), N-terminal pro-atrial natriuretic peptide (NT-proANP), interleukin (IL)-6, tumor necrosis factor alpha (TNF-alpha), epinephrine and norepinephrine were determined. Plasma apelin levels were similar in IDC patients (median 26.5 pg/ml, range<3.40-97.6 pg/ml) and in control subjects (median 24.1 pg/ml, range 19.0-28.7 pg/ml; p=NS). Unlike the levels of NT-proBNP, IL-6, TNF-alpha, and norepinephrine, plasma apelin levels did not reflect the severity of heart failure. Our study demonstrates that although disturbed apelin-APJ signalling in heart may play a role in the pathophysiology of heart failure, circulating apelin levels cannot be applied in the clinical assessment of patients with chronic left ventricular dysfunction.