Indicator Of Chronic Stress Research Articles

Hens with benefits: Can environmental enrichment make chickens more resilient to stress?

Resilience, the degree to which individuals are physiologically and behaviourally impacted by stressors, can be enhanced by positive experiences (e.g. positive moods in human, environmental enrichment in rodents). Such effects are important for human health, but could also have important animal welfare implications in terms of farm, laboratory and zoo animals’ abilities to cope with stressors. Here we investigated whether enrichments can increase resilience in chickens, the world's most abundant agricultural animal. The stress reactivity of laying hens housed for 5–6 weeks in enriched environments was compared to that of controls housed in smaller, emptier, less preferred pens, via: 1) startle reflex amplitudes to an abrupt, intense sensory stimulus (a light flash); and 2) autonomic responses to restraint and the sudden appearance of a novel object, assessed from decreases in comb temperature. Startle amplitudes were consistently reduced in the enriched hens, exerted with around one sixth the force seen in control hens. Maximum comb temperature decreases, and latencies for comb temperatures to return to prestress levels, also both fell by around a third. Enrichment thus reduced hens’ intrinsic behavioural and physiological responses to standardized stressors (doing so even outside the home pen), just as occurs in laboratory rodents. Enrichment also reduced baseline comb temperature, suggesting that this could be a non-invasive indicator of welfare. Altered judgment biases did not seem to be the mechanism. Further work should now investigate the processes underlying the apparently enhanced stress resilience of animals housed in preferred conditions, and also investigate baseline comb temperature as a chronic stress indicator in poultry.

Impact of Stress on Health and Final Weight in Fattening Lambs.

Simple SummaryIn recent years, the lamb production system in North-Eastern Spain has undergone an important change and the number of lamb feedlots has increased significantly. However, the possible impact of stressors associated with this production system on the health and productive performance of the lambs has not been investigated. In this study, the stress level of Rasa Aragonesa fattening lambs, finished at a commercial feedlot or on the farm of birth, was measured throughout the fattening period. Our results show that, although feedlot lambs seemed to have experienced higher stress levels than those fattened on the farm of origin, finishing location did not affect the probability of presenting clinical signs of illness and ovine respiratory complex lesions, or the final weight of the lambs. Notwithstanding, associations were found between the concentration of fecal cortisol metabolites (a chronic stress indicator) at the time of weaning and the health condition and the final weight of the lambs, regardless of the location at which they were fattened. The stress level experienced by lambs prior to finishing seems to be relevant for their health and productive performance, and measures to reduce this stress should be further investigated as a useful tool to improve the sustainability of the ovine production system. In order to determine whether the stress level had any influence on the health and final weight of Rasa Aragonesa fattening lambs, stress markers were measured throughout the fattening period in 80 feedlot lambs (group F) and in 40 lambs finished on the farm of birth (group C). The highest values of the stress indicators—neutrophil-to-lymphocyte-ratio (N/L), non-esterified fatty acids (NEFA), serum cortisol and fecal cortisol metabolites (FCM)—were recorded after the road transportation of group F to the feedlot. No differences between the groups were identified at the end of the adaptation period, but at the end of the fattening, statistically significant higher values for NEFA and serum cortisol were determined in group F. However, statistically significant differences between the groups were not found in the percentage of lambs with clinical signs of illness and ovine respiratory complex (ORC) lesions or in the final weight of the lambs. Independent of the location at which the lambs were fattened, those with FCM values at the beginning of the study (at the time of weaning) in the highest quartile developed a higher percentage of clinical signs of illness (45.5% vs. 32.1%, p > 0.05) and ORC lesions (45.5% vs. 10.7%, p < 0.01), and their average final weight was lower (24.36 kg vs. 27.40 kg, p = 0.001) than those with values in the lowest quartile. Stress experienced by lambs prior to finishing seems to be relevant for their further development, and FCM concentration at the time of weaning could be used as an indicator of health and productive performance of the lambs during the fattening period, regardless of finishing location.

Chemiluminescence Biosensor for Non-invasive Crew Health Monitoring at the International Space Station

Long-duration manned space missions require that astronauts be equipped with analytical devices suitable for performing on-site clinical-chemistry analysis. In the frame of the ???IN SITU Bioanalysis??? project, an analytical device for measuring the steroid hormone cortisol (an indicator of chronic stress) in saliva has been developed. The device performed a Lateral Flow Immunoassay (LFIA) for cortisol employing disposable plastic cartridges produced by FDM (Fused Deposition Modeling) 3D printing technology, which encapsulated a sealed fluidic element containing the LFIA strip and the reagents required for the analysis. Detection was performed by chemiluminescence (CL) using a dedicated CL reader equipped with a cooled charge-coupled device (CCD) camera. The European Space Agency (ESA) astronaut Paolo Nespoli successfully used the ???IN SITU Bioanalysis??? analytical device during the mission ???VITA???, a 6-months space mission onboard the International Space Station (ISS) in the framework of a dated bilateral agreement between the Italian Space Agency (ASI???Agenzia Spaziale Italiana) and NASA. The experiments proved the feasibility of CL-LFIA ultrasensitive (i.e., at the sub-ng/mL level) quantitative bioassays in space. In perspective, the ???IN SITU Bioanalysis??? analytical device could be adapted to the measurement of other biomarkers of diagnostic and prognostic relevance, even in a multiplexed fashion (i.e., detection of multiple biomarkers in a single analysis) to develop panels tests for diagnosis and follow-up of pathologies or monitoring health status of astronauts.

Chronic elevation of plasma cortisol causes differential expression of predominating glucocorticoid in plasma, saliva, fecal, and wool matrices in sheep

There is increasing interest in using nonblood measures of glucocorticoids to assess the physiological response to chronic stress conditions. In sheep, cortisol has been measured in various matrices including saliva, feces, and wool, but comprehensive studies of the relationship between plasma concentrations of cortisol and concentrations in these nonblood matrices are lacking. Therefore, we tested the hypothesis that administration of cortisol to sheep would result in elevated concentrations of cortisol in blood, saliva, feces, and wool. Merino ewes were administered with saline or 2 mg/kg BW/d hydrocortisone acetate (HCA) by intramuscular (i.m.) injection for 28 d. This treatment was imposed to mimic circulating cortisol concentrations experienced during periods of chronic stress. Cortisol and cortisone were directly measured in plasma, saliva, and wool before, during, and after treatment with saline or HCA. A 14-d pre-treatment and a 14-d post-treatment period were used to measure time taken for glucocorticoid concentrations in each of the matrices to return to baseline levels. Cortisol was also measured in feces before, during, and after treatment. Wool growth was also measured. Before treatment, there was no difference in the concentration of cortisol or cortisone in plasma, saliva, feces, or wool in animals treated with saline or HCA. In contrast, treatment with HCA increased (P < 0.05) concentrations of both cortisol and cortisone in plasma, saliva, and wool and of cortisol in feces. In plasma, cortisol concentrations were higher than cortisone (P < 0.05), whereas saliva cortisol and cortisone concentrations did not differ significantly. In wool, the concentration of cortisone was about 19-fold higher than that of cortisol during treatment and post-treatment periods. Treatment with HCA inhibited wool growth. These results demonstrate that an increase in glucocorticoids in the blood of sheep is reflected in increases in saliva (after 7 d of treatment), feces (21 d), and wool (14 d). Therefore, measures of glucocorticoids in these matrices may provide a measure of activation of the adrenal glands over time in sheep, thereby providing a retrospective indicator of chronic stress. With respect to wool, it appears that cortisol is predominantly metabolized to cortisone in the skin or wool follicle and is stored as cortisone. Therefore wool cortisone may also provide an important measure in quantifiying chronic stress in sheep.

Relationship between Child Sexual Abuse, Psychiatric Disorders and Infectious Diseases: A Matched-Cohort Study

ABSTRACT Child sexual abuse (CSA) has been strongly associated with a range of psychological and physical problems in childhood and adulthood, such as anxiety, post-traumatic stress disorder (PTSD), and infectious diseases. Despite the strength of these associations, no studies to date have investigated psychobiological processes that might underlie the relationship between CSA and physical health problems occurring during childhood, such as infectious diseases. The goal of the current study is to evaluate PTSD as a potential mediator between CSA and the occurrence of infectious diseases among children and adolescents. Furthermore, we postulate that PTSD plays a specific role as an indicator of chronic stress during childhood, in comparison to other mental disorders, such as anxious and non-anxious disorders (e.g., depression). Via a prospective matched-cohort design, administrative data were used to document PTSD, anxious and non-anxious disorders, and infectious diseases. The sample size was 882 persons with a substantiated report of sexual abuse and 882 matched controls. Negative binomial regressions revealed that CSA is associated with a greater number of anxious diseases diagnoses that, in turn, predict more infectious diseases diagnoses. These findings highlight the importance of preventing and intervening among sexually abused youth with anxious disorder symptoms to limit negative outcomes on physical health.

Men's Economic Dependency, Gender Ideology, and Stress at Midlife.

This study investigates the association between men's economic dependency during midlife and allostatic load, an indicator of chronic stress, and how this relationship varies with men's gender ideology. Women are primary breadwinners in almost a third of heterosexual couples in the U.S. Emerging research finds that female primary breadwinning (or men's economic dependency) is a threat to masculinity that has negative implications for men's midlife health. However, there is no quantitative evidence of the mechanisms linking men's economic dependency and health, particularly the role of stress, and whether men's gender ideology moderates this relationship. Using two waves of Midlife in the United State (MIDUS) data for men who remained with the same marital or cohabiting female partner between waves (n = 332), the authors estimate the relationship between men's economic dependency in wave 1 and allostatic load in wave 2. There was no evidence of an association between men's economic dependency and higher allostatic load on average. However, gender ideology had a moderating influence; men's economic dependency was associated with higher allostatic load for those who espoused more traditional gender attitudes and lower allostatic load for those with the most egalitarian attitudes. The findings underscore the existence of multiple masculinities and suggest that economic dependence has a negative or positive influence on men's health depending on the meanings men attach to female primary breadwinning.

Which trees die during drought? The key role of insect host‐tree selection

Abstract During drought, the tree subpopulations (such as size or vigour classes) that suffer disproportionate mortality can be conceptually arrayed along a continuum defined by the actions of biotic agents, particularly insects. At one extreme, stress dominates: insects are absent or simply kill the most physiologically stressed trees. At the opposite extreme, host selection dominates: outbreaking insects kill trees independently of their stress, instead selecting trees based on size or other traits. Intermediate responses are also possible. Yet for mixed‐species forests, we lack a broad understanding of the relative importance of insects in determining exactly which subpopulations of trees suffer disproportionate mortality during drought, and whether these subpopulations differ among co‐occurring tree species. During an extreme drought, we documented the roles of native bark beetles in the mortality of five tree species in California’s Sierra Nevada. We analysed the patterns and agents of tree mortality in 12 permanent plots and the patterns of mortality in 89 temporary plots. Most tree mortality was associated with bark beetles. However, the growth rates (an indicator of chronic stress) and sizes of trees that suffered greatest bark beetle‐related mortality differed sharply among tree taxa, variously conforming with domination by stress (Abies concolor), domination by host selection (Pinus lambertiana and P. ponderosa) or a mix of the two (Calocedrus decurrens). Quercus kelloggii mortality remained relatively low. Thus, even during extreme drought substantial proportions of stressed trees survived because they were of sizes that mostly avoided fatal insect attack. Conversely, substantial proportions of comparatively unstressed trees died because they were of sizes that were selectively killed by outbreaking insects. Synthesis. Native bark beetles were primarily responsible for determining which subpopulations of trees suffered greatest mortality during drought. However, idiosyncratic host‐tree selection by the different bark beetle taxa meant that the tree subpopulations suffering greatest mortality differed strikingly among tree taxa—for example, high mortality of small trees of one species, but of large trees of another. If idiosyncratic host‐tree selection by biotic mortality agents proves to be a generally common phenomenon, it could help explain weak broadscale correlations between tree traits and tree mortality during drought.

Examining reactivity patterns in burnout and other indicators of chronic stress

IntroductionBurnout symptomatology is associated with various negative health consequences; however, the mechanisms underlying these associations remain unclear. One potential pathway involves alterations in the acute stress response. The aims of the present study were to examine burnout-associated alterations in stress-reactivity patterns, during a standardized social stressor compared to a control condition, as well as to examine whether effects associated with greater burnout symptomatology were distinct from other, conceptually overlapping indicators of chronic stress (i.e. depressive symptomatology and elevated hair cortisol concentration [HCC]). Materials and methodsIn a randomized two-factor design a total of 70 employed males with varying burnout symptoms but without evidence of physical or psychiatric disease were exposed to the Trier Social Stress Test for Groups (TSST-G) or a non-stressful control condition. Acute stress reactivity was assessed using self-report stress measures and non-invasive biomarkers. Associations among acute stress reactivity, burnout and depressive symptoms (assessed with self-report measures), as well as HCC were analysed using repeated measure ANCOVAs and moderation analysis. ResultsBurnout symptomatology was associated with elevated stress perception independent of the experimental condition. In addition, depressive symptomatology was associated with enhanced anticipatory appraisal, whereas HCC was not related to any subjective stress measure. On a physiological level, burnout and depressive symptomatology, as well as HCC were associated with a pattern of blunted cardiovascular reactivity, however the timing of this effect varied. ConclusionOur results indicate burnout-associated modulations in stress reactivity, which diverge, at least partly, from other indicators of chronic stress.

Blubber transcriptome responses to repeated ACTH administration in a marine mammal

Chronic physiological stress impacts animal fitness by catabolizing metabolic stores and suppressing reproduction. This can be especially deleterious for capital breeding carnivores such as marine mammals, with potential for ecosystem-wide effects. However, the impacts and indicators of chronic stress in animals are currently poorly understood. To identify downstream mediators of repeated stress responses in marine mammals, we administered adrenocorticotropic hormone (ACTH) once daily for four days to free-ranging juvenile northern elephant seals (Mirounga angustirostris) to stimulate endogenous corticosteroid release, and compared blubber tissue transcriptome responses to the first and fourth ACTH administrations. Gene expression profiles were distinct between blubber responses to single and repeated ACTH administration, despite similarities in circulating cortisol profiles. We identified 61 and 12 genes that were differentially expressed (DEGs) in response to the first ACTH and fourth administrations, respectively, 24 DEGs between the first and fourth pre-ACTH samples, and 12 DEGs between ACTH response samples from the first and fourth days. Annotated DEGs were associated with functions in redox and lipid homeostasis, suggesting potential negative impacts of repeated stress on capital breeding, diving mammals. DEGs identified in this study are potential markers of repeated stress in marine mammals, which may not be detectable by endocrine profiles alone.

Abstract # 3126 Impact of chronic and acute academic stress on lymphocyte subsets and monocyte function

This study investigated the effects of a temporally confined naturalistic stressor (academic stress) on immune functions. Furthermore, moderating influences of a number of psychological variables were assessed. Five blood samples were obtained from 20 students during an observation period of 8 weeks, starting 4.5 weeks before an exam period up to 1 week following the last exam. The analysis of 45 immune parameters revealed several time-dependent changes attributable to examination stress. We observed a reduction in the absolute numbers of natural killer (NK) cells and monocytes in peripheral blood and a shift towards more immature and naive cells within NK and T cell populations. In addition, IL-6 and TNF-alpha production by LPS-stimulated monocytes was increased. Psychological variables were grouped by means of factor analyses into two factors. One factor, which was interpreted as an indication of chronic stress, moderated the relationships between academic stress and percentages of mature CD57+NK cells. This chronic stress factor was also associated with an increase in memory and a decrease in naive CD8 T cells and increased serum levels of IL-17. The present study identifies important potential psychological mediators of stress-induced changes in specific immunological parameters.

Chronic and acute stress monitoring by electrophysiological signals from adrenal gland

We present electrophysiological (EP) signals correlated with cellular cell activities in the adrenal cortex and medulla using an adrenal gland implantable flexible EP probe. With such a probe, we could observe the EP signals from the adrenal cortex and medulla in response to various stress stimuli, such as enhanced hormone activity with adrenocorticotropic hormone, a biomarker for chronic stress response, and an actual stress environment, like a forced swimming test. This technique could be useful to continuously monitor the elevation of cortisol level, a useful indicator of chronic stress that potentially causes various diseases.

Temporal profiles of cortisol accumulation and clearance support scale cortisol content as an indicator of chronic stress in fish.

The development of chronic stress indicators for fish is of great interest, but appropriate non-invasive methods are lagging those used in terrestrial vertebrates. Here, we explore the possibility that levels of the stress hormone cortisol in scales could be used as a chronic stress indicator. Three experiments were conducted to assess the temporal profiles of cortisol rise and fall in plasma and scales of goldfish (Carassius auratus) in response to stressors of varying intensity and duration. Results show that a single acute air emersion stressor does not influence scale cortisol content. In contrast, relative to plasma levels, the fall in scale cortisol content following a high-dose cortisol implant is delayed by at least 8 days, and the rise and fall in scale cortisol content in response to unpredictable chronic stress are delayed by at least 7 days. Also, scale cortisol content is spatially heterogeneous across the body surface of goldfish. Overall, since high and sustained circulating cortisol levels are needed to influence scale cortisol content and the rates of cortisol accumulation and clearance are much slower in scales than in plasma, our results show that scales can provide an integrated measure of cortisol production and serve as a chronic stress indicator.

Impact of Two Forms of Daily Preventive Zinc or Therapeutic Zinc Supplementation for Diarrhea on Hair Cortisol Concentrations Among Rural Laotian Children: A Randomized Controlled Trial.

Zinc supplementation has been shown to reduce the morbidity burden among young children, and may reduce chronic stress. Hair cortisol has been promoted as an indicator of chronic stress. We assessed the impact of different strategies for delivering supplementary zinc on hair cortisol concentrations (HCC) in young Laotian children and examined risk factors associated with HCC. In a randomized double-blind controlled trial (NCT02428647), children aged 6–23 mo were randomized to one of four intervention groups and followed for ~36 weeks: daily preventive zinc (PZ) tablets (7 mg/day), daily multiple micronutrient powder (MNP) sachets (containing 10 mg zinc and 14 other micronutrients), therapeutic zinc (TZ) supplements for diarrhea treatment (20 mg/day for 10 days) or daily placebo powder. HCC of 512 children was assessed at baseline and endline. ANCOVA and linear regression models were used to assess group differences in HCC and to examine the risk factors associated with HCC, respectively. At enrollment, mean HCC was 28.8 ± 43.9 pg/mg. In models adjusted for age at enrollment, health district, and baseline HCC there was no overall effect of the interventions on endline HCC and change in HCC. When controlling for additional predetermined covariates, there was a marginally significant effect on change in HCC (p = 0.075) with a slightly lower reduction of HCC in TZ compared to PZ (mean change (95% CI): −4.6 (−7.0; −2.3) vs. −9.4 (−11.7; −7.0) pg/mg; p = 0.053). At baseline, consumption of iron rich foods was negatively associated with HCC, whereas AGP (α1-acid glycoprotein) levels, elevated AGP and C-reactive protein and high soluble transferrin receptor were positively associated with HCC. In young Laotian children, MNP, PZ and TZ had no impact on HCC. The marginal difference in change in HCC between the PZ and TZ groups was too small to be considered of health significance.

Reduced professional efficacy is associated with a blunted salivary alpha-amylase awakening response

The job demands-resources model (JD-R) has shown an ability to predict worker engagement and exhaustion, yet to our knowledge, research has not been conducted that assesses the JD-R model with physiological indicators of chronic stress and burnout. Using the JD-R model, we assessed if occupational stress and burnout were related to dysregulated cortisol and salivary alpha-amylase awakening responses (sAA-AR). Professional apprentice jockeys comprising of males (n = 14) and females (n = 18) provided morning saliva samples and completed self-report measures relating to job demands and resources, burnout, and perceived mental and physical health. Data was collected at two time points coinciding with naturally occurring ‘low’ and ‘high’ stress periods during the racing calendar. The jockeys reported good physical and mental health but had elevated levels of the burnout subtypes cynicism and exhaustion. Regression analyses suggested that those jockeys presenting with reduced professional efficacy in the high stress period produced a ‘flattened’ sAA-AR indicative of reduced autonomic nervous system (ANS) arousal, which has been associated with burnout. Further, decreases in professional efficacy explained the relationship between increased workplace stress and decreased ANS activity in the high stress period. Our findings suggest that assessments of psychological stress or physiology in isolation are not as useful as looking at both in combination, and extend previous findings on the sAA-AR.

The Effect of High-Intensity Intermittent Exercise on Chronic Stress and Potential Biomarkers: a Pilot Study

Persons employed in highly stressful occupations are at a heightened risk for developing chronic stress-related disorders. These disorders are associated with immunosuppression, disease progression and psychological illness. Exercise has previously been used to combat depression; however, police personnel are already moderately active yet still stressed. Therefore, this pilot study aims to determine if high-intensity intermittent training (HIIT) could be a potential stress-reducing strategy in already trained persons, and which biological markers could be measured in a larger study. Using three single case studies, this study employed a 10-week HIIT intervention and measured markers of stress via Perceived Stress Scale (PSS) scores, cortisol levels and associated inflammation blood markers at baseline and post-intervention. The PSS scores reduced after HIIT (36–40%). Cortisol secretion pre-intervention indicated a flat profile during daytime hours; post-intervention showed increased levels in the morning and an overall normal daytime profile. Of the inflammation blood markers, eosinophil cell counts were halved post-intervention. HIIT, therefore, is a potential stress-reducing strategy in already trained individuals. The decreased psychological stress was associated with normalization of cortisol hormone function and reduced systemic inflammation via lower eosinophil counts, which highlighted the specific physiological markers as indicators of chronic stress.

DNA damage as an indicator of chronic stress: Correlations with corticosterone and uric acid

Corticosterone does not change in consistent ways across species and contexts, making it challenging to use as an indicator of chronic stress. We assessed DNA damage as a potential metric that could be a more integrative stress measurement with direct links to health. We captured free-living house sparrows, took an immediate blood sample, and transferred them to the laboratory, exposing them to the chronic stress of captivity. Biweekly blood and weight samples were then taken for 4 weeks. We immediately assessed DNA damage in red blood cells using the comet assay and later quantified corticosterone. Uric acid was analyzed in a separate group of birds. We found that birds initially lost, but began to regain weight over the course of captivity. DNA damage peaked within the first 10 days of captivity, and mostly remained elevated. However, the cellular distribution of damage changed considerably over time; most cells showed low levels of damage early, a bimodal distribution of high and low DNA damage during the peak of damage, and a wide unimodal distribution of damage at the end of the 4 weeks. Furthermore, corticosterone increased and remained elevated and uric acid decreased and remained depleted over the same period. Although both a molecular (DNA damage) and an endocrine (corticosterone) marker showed similar response profiles over the 4 weeks, they were not correlated, suggesting they reflect different aspects of the underlying physiology. These data provide convincing preliminary evidence that DNA damage has potential to be an additional indicator of chronic stress.

Ecotourism effects on health and immunity of Magellanic penguins at two reproductive colonies with disparate touristic regimes and population trends.

Negative effects of ecotourism on wildlife are rising worldwide. Conservation physiology can play a major role in protecting wildlife by providing early alerts on changes in the status of individuals exposed to tourist activities. We measured an integrated set of immune and health-state indices to evaluate the effects of ecotourism on Magellanic penguins (Spheniscus magellanicus). We studied two reproductive colonies that differed in the intensity of tourism and population trends: Punta Tombo (higher tourism intensity, declining population) and San Lorenzo (lower tourism intensity, growing population). Within each colony, we compared individuals from an area that was exposed to tourists and a control area where tourism was excluded. Adult penguins exposed to tourism at Punta Tombo, but not at San Lorenzo, showed physiological alterations indicative of chronic stress (higher heterophil to lymphocyte ratios) and parasitic infection (elevated heterophil and eosinophil counts). Penguin chicks exposed to tourism at Punta Tombo, but not at San Lorenzo, also showed physiological alterations indicative of poor immune and general-health condition: lower humoral innate immunity, haematocrit, and glucose levels and higher inflammatory responses likely due to increased prevalence of fleas. Our results indicate that individuals of a declining population exposed to high levels of tourism express physiological indicators of chronic stress and poor health that could make adults and juveniles vulnerable to disease. These effects are expressed despite a long history of exposure and behavioural habituation to human visitation. In contrast, individuals of a growing population exposed to more recent and lower levels of tourism showed no effect. Our study demonstrates how a diverse physiological toolkit within a conservation physiology approach can provide important information for a better comprehension of anthropogenic effects on wild animals in our changing world.

Impact of chronic and acute academic stress on lymphocyte subsets and monocyte function

This study investigated the effects of a temporally confined naturalistic stressor (academic stress) on immune functions. Furthermore, moderating influences of a number of psychological variables were assessed. Five blood samples were obtained from 20 students during an observation period of 8 weeks, starting 4.5 weeks before an exam period up to 1 week following the last exam. The analysis of 45 immune parameters revealed several time-dependent changes attributable to examination stress. We observed a reduction in the absolute numbers of natural killer (NK) cells and monocytes in peripheral blood and a shift towards more immature and naïve cells within NK and T cell populations. In addition, IL-6 and TNF-α production by LPS-stimulated monocytes was increased. Psychological variables were grouped by means of factor analyses into two factors. One factor, which was interpreted as an indication of chronic stress, moderated the relationships between academic stress and percentages of mature CD57+ NK cells. This chronic stress factor was also associated with an increase in memory and a decrease in naïve CD8 T cells and increased serum levels of IL-17. The present study identifies important potential psychological mediators of stress-induced changes in specific immunological parameters.

Educators' emotion regulation strategies and their physiological indicators of chronic stress over 1year.

Studies show teaching is a highly stressful profession and that chronic work stress is associated with adverse health outcomes. This study analysed physiological markers of stress and self-reported emotion regulation strategies in a group of middle school teachers over 1year. Chronic physiological stress was assessed with diurnal cortisol measures at three time points over 1year (fall, spring, fall). The aim of this longitudinal study was to investigate the changes in educators' physiological level of stress. Results indicate that compared to those in the fall, cortisol awakening responses were blunted in the spring. Further, this effect was ameliorated by the summer break. Additionally, self-reported use of the emotion regulation strategy reappraisal buffered the observed blunting that occurred in the spring.

The relationship of PLR to stereotypic behaviors and neurotransmitters in sows

Abstract This study aimed to validate the relationship between pupillary light reflex (PLR) and stereotypic behaviors or serum neurotransmitters in confined sows. Eight long PLR latency (LL) sows (reaction time ≥10 seconds) and 8 short PLR latency (SL) sows (time of PLR P > 0.05). Sitting in LL sows was significantly higher ( P ≤ 0.05), and grooming was lower in frequency ( P P > 0.05), but trough-biting and sham-chewing in LL sows were higher than for SL sows ( P ≤ 0.05). However, DA and 5-HT levels were higher in LL sows than SL sows ( P = 0.05 and P = 0.02, respectively). The results also indicated that bar-biting was negatively correlated with 5-HT levels ( r = 0.542; P r = 0.582; P r = 0.499; P = 0.01). The results of this study suggest that sows' PLR is related to serum neurotransmitters and stereotypic behaviors and that the prolonged latency of PLR might have potential to be indicator of chronic stress or depression.