Significant Increase In Cortisol Levels Research Articles

Polystyrene nanoplastics disrupt hepatic vitellogenin metabolism and impairs the reproduction process in female zebrafish

Abstract For this study, a number of 240 adult healthy female zebrafish were divided into 12 tanks (20 fish per tank) and exposed to 0 (control, T0), 0.1 (T1), 1 (T2), and 10 (T3) mg/L synthesized polystyrene nanoplastics (PS-NPs, Nanoplastic synthesized in the chemistry laboratory of Faculty of Basic Sciences at Zabul University) for 4 weeks. At the end of the experiment, exposure to PS-NPs had no significant affect the survival of female zebrafish (p > 0.05). A significant decrease of hepatic vitellogenin (Vtg) were seen in female zebrafish exposed to PSNPs (p < 0.05). The level of 17β estradiol (E2) and testosterone (T) were notably declined in female zebrafish of all PS-NPs-exposed groups (p < 0.05). Glucose was notably increased in female zebra fish of all PS-NPs-exposed treaments (p < 0.05). There was a significant increase in cortisol levels in all PS-NPs-exposed treaments (p < 0.05). No significant diffrenece was seen in lactate levels between different treatments (p > 0.05). A significant enhancement in aspartate aminotransferase (AST), alanine transaminase (ALT) and alkaline phosphatase (ALP) was observed in female zebra fish of all PS-NPs-exposed treaments than the control (p < 0.05). The present results demonstrate that PS-NPs impairs the reproduction process so that none of the female zebrafish broodstock exposed to different doses of PS-NPs have not spawn.

Plasma cortisol and production of miRNAs in red drum (Sciaenops ocellatus) exposed to three distinct challenges.

The red drum Sciaenops ocellatus is a marine fish species of high commercial interest. Despite improvements in current aquaculture practices, there are still concerns about the impact of daily manipulations regarding fish welfare. To investigate how does fish respond to various challenges, S. ocellatus juveniles were submitted to two acute challenges, namely a confinement stress and a cold-temperature shock, as well as a chronic stress challenge consisting of 18days of repetitive challenge events. The level of cortisol produced by individuals was used as a measure of activation hypothalamic-pituitary-interrenal (HPI) axis. A significant increase in cortisol levels was detected only after the confinement stress. Interestingly, the fish exposed to a chronic stress for 18days exhibited cortisol levels significantly lower than those of non-challenged fish. The small RNA-sequencing conducted for the chronic stress experiment only allowed us to identify two plasmatic microRNAs more abundant in non-challenged fish (miR-205-1-5p and let-7b-5p) compared to challenged fish. The miR-205-1-5p was of particular interest since it was already detected in previous studies on other fish species. In silico analysis allowed to predict potentially highly conserved mRNA targets of this specific miRNA, among which is tnfrsfa that plays a key role in the secondary stress response.

The puzzling etiologies of transient black discoloration in Nile Tilapia (Oreochromis niloticus) intensively cultured under RAS system

The aim of this study is to identify the hidden etiologies of the black chromo-shifting transient phenomenon affecting Nile tilapia, Oreochromis niloticus, farmed in RAS-controlled ponds together with the assessment of the immunological reaction against the chronic irritating effects of the invasive agent. A total of 100 Nile Tilapia were collected from a private farm at Kafrelsheikh Province, located on the northern side of the Egyptian Nile Delta. The clinical history of the affected fish farm showed an unknown chromo-shifting phenomenon where tilapias were exhibiting severe black skin coloration, which gradually disappeared after removal from the tank’s water. A comprehensive gross examination of the collected fish; including parasitological examination of skin and gill scraps, was performed. Blood biochemical testing was performed on the infested blackish O. niloticus and control non-infested fish. The current study showed that the monogenean parasite, Gyrodactylus cichlidarum, was the abundant parasite detected in the infested fish leading to abnormal black discoloration of skin and disruption of the immune system represented by significant increase of cortisol levels, lysozyme activity and different liver enzymes compared to the control. Treatment trials have been applied with moderate degrees of success, where the monogenean count was sharply decreased, and the normal skin color was remarkably restored, at the end of day 14 post-treatment. A triple treatment plan was initiated through 7 days’ application of 0.7 g/m3 copper sulfates pentahydrate preceded by 1.5 ml/m3 hydrogen peroxide 40% solution for the same period. One day after the end of the initial treatment, a maintenance dosage of 0.095 ml/m3 of glutaraldehyde (15%)/quaternary ammonium compounds (QACs) mixture was administered for 3 days. As a supportive/immune-stimulant regimen, a weekly dosage of vitamin C (0.45 g g/m3) and Saccharomyces cerevisiae (0.45 g/m3) was added into the tank’s water to improve the general fish health.

Dehydroepiandrosterone sulfate to cortisol ratio as a prognostic factor in cirrhotic patients with spontaneous bacterial peritonitis

BackgroundChronic liver disease and decompensated cirrhosis are associated with serious complications; spontaneous bacterial peritonitis is considered one of them that may lead to sepsis and adrenal insufficiency. This trial aimed to study the role of dehydroepiandrosterone sulfate (DHEAS) and DHEAS/cortisol ratio for assessing cirrhotic patients’ adrenal function and as a possible prognostic factor in cirrhotic cases with spontaneous bacterial peritonitis (SBP).Patients and methodsIt was a prospective cohort trial carried out on 100 patients in the Internal Medicine Department, Tanta University Hospital, from June 2021 to July 2022 divided into 2 studied patient groups: group I, 50 cases with liver cirrhosis and sterile ascites; and group II, 50 cases with liver cirrhosis and SBP. Adrenal function was evaluated using serum cortisol levels (9 A.M, 9 P.M, and post synacthen stimulation test), DHEAS level, and DHEAS/cortisol ratio.ResultsThe cirrhotic patients with SBP have significantly decreased DHEAS, decreased DHEAS/cortisol ratio, and high cortisol level post stimulation compared with patients with sterile ascites, cirrhotic cases with decreased DHEAS/cortisol ratio (< 0.65) had elevated C-reactive protein (CRP) levels, a higher model for end-stage liver disease (MELD) score and Child–Pugh score had higher hospital mortality. Both DHEAS and the DHEAS/cortisol ratio were significant predictors of hospital mortality (area under the receiver operating characteristic curve 0.267 and 0.298, respectively). The cirrhotic patients with SBP had decreased DHEAS and DHEAS/cortisol ratio but higher hospital mortality, compared to the cirrhotic patients with sterile ascites.ConclusionsIt was found that a significant increase in cortisol level was after synacthen stimulation, decreased DHEAS, and low DHEAS to cortisol ratio in the cirrhotic patients with spontaneous bacterial peritonitis and was associated with high mortality compared to cirrhotic patients without spontaneous bacterial peritonitis.

Effect of Hatha Yoga and meditation on academic stress in medical students—Clinical trial

IntroductionMedical students use to deal with high levels of academic stress. Hatha yoga and meditation have been found to reduce variables associated with stress. Objective: To evaluate and compare the effect of Hatha yoga and meditation on academic stress in medical students at a private university in Cali, Colombia. Methods and materialsA total of 27 volunteers were randomly divided into two groups: Hatha Yoga(n = 13) and Meditation (n = 14). Each group undertook two weekly one-hour sessions for 14 weeks. Study outcomes were salivary cortisol and perceived academic stress. Anthropometric and clinical variables were additionally measured as characteristics of the study sample. Perceived academic stress was estimated via a structured questionnaire. An intra-group analysis was also conducted to compare the outcomes at baseline and post-intervention within the groups. ResultsAt baseline demographic, clinical, and anthropometric variables were similar between the intervention groups. After the intervention, no differences were found between meditation and hatha yoga groups in salivary cortisol measures (time 0, 15, 30, 45 min, and mean of the 4 measures) and perceived academic stress. However, the intra-group analysis showed that only in Hatha yoga there was a significant increase in cortisol measures and improvement in the scale of perceived academic stress. ConclusionBased on the intra-group but not between-group comparisons of outcomes at baseline and post-intervention, Hatha yoga reduced perceived academic stress despite a concomitant significant increase in cortisol levels. Further trials with larger samples of medical students should be conducted to contrast our findings.

Unfamiliar human-induced social buffering effect in kennel-residing Australian Cattle Dogs

The "isolation syndrome" is a term used to describe the stress responses observed in highly social species when they lack social interactions. This syndrome affects various aspects of an individual's welfare, including hormonal, behavioral, and physiological systems. Dogs, known for their social nature, have been used as a model to study the effects of social buffering provided by conspecifics or humans. This study aims to investigate the social buffering effect of humans on dogs and determine if it is solely associated with bonding or socialization. The study selected Australian Cattle Dogs with limited social interactions with humans, ensuring that no direct bonds or human socialization were involved. The dogs were randomly assigned to either an isolation or social condition, and cortisol levels were measured before and after the tests to evaluate stress responses. The results showed that isolation led to a significant increase in cortisol levels, indicating a stress response. However, in the presence of unfamiliar humans, cortisol levels did not increase significantly, suggesting a lack of stress response. This finding suggests that humans can serve as social buffers for dogs, even without prior bonding or socialization. Therefore, dogs without systematic human socialization still benefited from the presence of unfamiliar humans.

Biochemical and reproductive biomarker analysis to study the consequences of heavy metal burden on health profile of male brick kiln workers

The present study aims to assess the effect of a heavy metal burden on general health, biochemical parameters, an antioxidant enzyme, and reproductive hormone parameters in adult male brick kiln workers from Pakistan. The study participants (n = 546) provided demographic data including general health as well as body mass index. Blood was collected to quantitatively assess hematological, biochemical, and reproductive hormone parameters as well as heavy metal concentrations using both atomic absorption spectroscopy (AAS) and particle-induced X-ray emission (PIXE). The data showed that 10% of the brick kiln workers were underweight and 10% obese (P = 0.059), with workers also reporting multiple health issues. Heavy metal concentrations utilizing AAS revealed significantly (p = 0.000) higher levels of cadmium, chromium, and nickel, while PIXE detected more than permissible levels of Si, P, S, Cl, K, Ca, Zn, Ti (p = 0.052), Mn (p = 0.017), Fe (p = 0.055), Co (p = 0.011), Ni (p = 0.045), and Cu (p = 0.003), in the blood of kiln workers. Moreover, a significant increase in platelet count (P = 0.010), a decrease in sodium dismutase levels (p = 0.006), a major increase in reactive oxygen species (p = 0.001), and a reduction in protein content (p = 0.013) were evident. A significant increase in cortisol levels (p = 0.000) among the workers group was also observed. The concentration of LH and FSH increased significantly (p = 0.000), while that of testosterone decreased (p = 0.000) in the worker group compared with controls. A significant inverse relationship was found between cortisol, LH (r = − 0.380), and FSH (r = − 0.946), while a positive correlation between cortisol and testosterone was also evident (r = 0.164). The study concludes that increased heavy metal burden in the blood of brick kiln workers exposes them to the development of general and reproductive health problems due to compromised antioxidant enzyme levels, increased oxidative stress conditions, and a disturbing reproductive axis.

Evaluation of the effect of tongue ties on stress parameters, behaviour and heart-rate variability in racehorses

AbstractFixation of the tongue to the mandible using so-called tongue ties (TTs) is common practice in Standardbred (SB) and Thoroughbred (TB) racing, but little is known about their impact on animal welfare. In this study, the influence of TTs on heart-rate variability (HRV), stress parameters in plasma (cortisol, glucose, lactate) and behaviour was evaluated in 30 SBs and 29 TBs (n = 59) presenting with exercise insufficiency. Overall, 36/59 horses (24 SBs, 12 TBs) were familiar with TTs. Blood was taken at rest, after TT application and after racing in all horses, additionally samples were taken without TT in SBs another day. HRV was calculated over 3 min before, during and after racing. Additionally, SBs’ behaviour during TT application and racing was documented in real time. TT application did not increase cortisol levels significantly, while highly significant increases in cortisol levels were found after racing. Lactate levels were not influenced by TT application, but also significantly increased after racing. No significant differences were found for glucose. Seventeen out of 30 SBs showed mild (n = 8), moderate (n = 8) and severe (n = 1) reactions during TT application, none during or after race training. At rest, 23/30 SBs had a low/high frequency (LF/HF) ratio &lt; 1.5 (1.05 [± 0.61], n = 30, dominating parasympathetic activity). After TT application, the LF/HF ratio increased to 1.4 (± 0.45) (increased sympathetic activity). In TBs, sympathetic activity dominated at rest. No differences in LF, HF and LF/HF were found after TT application or comparing HRV after racing with/without TT. The stress response (blood parameters and HRV) was not influenced by horses’ naivety to TTs, however an increased stress response was observed in SB mares. Overall, obvious adverse behaviour, but only slight evidence of an increased systemic stress response, was found in this study. These results might provide objective evidence for future decisions from equine sports organisations concerning further regulations on TTs.

Dietary Inclusion of Hydrolyzed Debaryomyces hansenii Yeasts Modulates Physiological Responses in Plasma and Immune Organs of Atlantic Salmon (Salmo salar) Parr Exposed to Acute Hypoxia Stress.

Stress related to salmon aquaculture practices (handling, sub-optimal nutrition, diseases, and environmental problems) may compromise fish welfare. This study describes the effects of two hydrolyzed Debaryomyces hansenii yeast-based products (LAN4 and LAN6) on physiological and immune responses of Atlantic salmon (Salmo salar) parr exposed to short hypoxia stress. A commercial-like diet (control diet: CD) and two experimental diets (CD supplemented with 0.1% of either component LAN4 or LAN6) were fed to fish for 8 weeks. At the end of the feeding experiment, fish were exposed to 1-min hypoxia and samples were collected at 0, 1, 3, 6, 12, and 24 h post-stress. Results showed that plasma cortisol reached a peak at 1 h post-stress in CD and LAN6 groups, whereas no significant increase in cortisol levels was detected in the LAN4 group. Moreover, the LAN6 group enhanced IL-10 responses to hypoxia, when compared to the control and LAN4 group. This suggests a regulation of immunosuppressive profiles in fish fed LAN4. Hypoxia stress increased TNFα in all groups, which indicates that fish may compensate for the short-term stress response, by modulating innate immune molecules. The apparent suppression of hypoxia responses in the LAN4 group coincided with the detection of differences in goblet cells size and Muc-like proteins production in DI; and upregulation (1 h post-stress) of pathways related to oxygen transport, hemoglobin complex, and glutathione transferase activity and the downregulation of fatty acid metabolism (6 h post-stress) in gills. To conclude, a 1-min hypoxia stress exposure affects the response to stress and immunity; and D. hansenii-based yeast products are promising components in functional aquafeeds for salmon due to their ability to counteract possible consequences of hypoxic stress.

Evaluation of Ammonia Nitrogen Exposure in Immune Defenses Present on Spleen and Head-Kidney of Wuchang Bream (Megalobrama amblycephala).

Ammonia is one of the most important environmental factors in aquatic ecosystems. However, there are limited studies on the effects of chronic or long-term ammonia stress and its potential molecular mechanism in fish. This study aimed to investigate the immune response and molecular mechanisms in the spleen and head-kidney of fish following chronic ammonia exposure. Megalobrama amblycephala (9.98 ± 0.48 g) were exposed to different concentrations of total ammonia nitrogen (0–30 mg/L) for 30 days. Ammonia exposure caused significant increases in cortisol levels and decreases in lysozyme and complement 3/4 concentrations in the serum, indicating inhibitory effects of ammonia stress on innate immune responses. Ammonia exposure also induced concentration-dependent increases in ammonia concentrations in tissue, pathological damage and indexes of spleen and head-kidney. Additionally, the contents of immunoglobulin M (IgM), interleukin 1β (IL-1β) and tumor necrosis factor α (TNF-α) as well as mRNA levels of toll-like receptors (TLRs)/Myeloid differentiation factor 88 (MyD88)-independent signaling molecules in the spleen and head-kidney were significantly downregulated after ammonia exposure. Our findings suggested that chronic ammonia exposure caused the suppression of innate and adaptive immune responses through downregulating TLR/MyD88-independent signaling. Adverse influences of chronic ammonia stress were more severe in the spleen than in the head-kidney.

Oxidative stress and motion sickness in one crew during competitive offshore sailing

Competitive Offshore Ocean Sailing is a highly demanding activity in which subjects are exposed to psychophysical stressors for a long time. To better define the physiological adaptations, we investigated the stress response of subjects exposed to 3-days long ocean navigation with disruption of circadian rhythms. 6 male subjects were involved in the study and provided urine and saliva samples before setting sail, during a single day of inshore sailing, during 3-days long ocean navigation, and at the arrival, to measure oxidative stress, cortisol, nitric oxide metabolites (NOx) and metabolic response. Motion Sickness questionnaires were also administered during the navigation. The crew suffered a mean weight loss of 1.58 kg. After the long navigation, a significant increase in ROS production and decrease in total antioxidant capacity and uric acid levels were observed. Lipid peroxidation, NO metabolites, ketones, creatinine, and neopterin levels were also increased. Furthermore, a significant increase in cortisol levels was measured. Finally, we found a correlation between motion sickness questionnaires with the increase of NOx, and no correlation with cortisol levels. Physical and psychological stress response derived from offshore sailing resulted in increased oxidative stress, nitric oxide metabolites, and cortisol levels, unbalanced redox status, transient renal function impairment, and ketosis. A direct correlation between motion sickness symptoms evaluated through questionnaires and NOx levels was also found.

HEPATOPROTECTIVE ACTION OF AQUEOUS EXTRACT OF Artemisia pallens lEAVES IN CLOFIBRATE AND PHENOL TREATED FRESHWATER FISH Pangasius Sp.

Aim: The key motive was to investigate the toxicological upshot of clofibrate and phenol prescribed under human medicine, having potential in water and sediments contamination via input from sewage treatment plants as active pharmaceutical ingredients’ discharge into the environment had kindled present catastrophic effects upon the aquatic ecosystem. Methods: The present study involved, exposing the fish model, Pangasius sp. after acclimatizing them at a suitable LC50 concentration of selective drugs. Their toxic effects were studied in terms of oxidative stress markers, antioxidant status, and protein damage levels in the occupancies under the bioremediation source, Artemisia pallens and further supported by histopathological and cortisol level studies. Results: The results’ comparison between fish maintained under the bioremediation source, when exposed to clofibrate and phenol resulted in severe oxidative stress (significant *P&lt;0.001, #P&lt;0.001) with significant alterations in antioxidant enzyme activities (significant *P&lt;0.001, #P&lt;0.001), histopathological changes and cortisol levels. In the fish exposed to clofibrate and phenol, the significant increase in cortisol level (significant *P&lt;0.05, #P&lt;0.05) may confer distinctive effects on the cell survival by protecting against oxidative stress-induced changes. Conclusion: Since these results varied with the dwelling of the bioremediation source, determination of oxidative stress biomarkers in Pangasius along with Artemisia pallens may serve as a convenient approach for pollution biomonitoring.

Cortisol levels in narwhal (Monodon monoceros) blubber from 2000 to 2019

Narwhals (Monodon monoceros Linnaeus, 1758) summering on northern Baffin Island are experiencing increases in vessel traffic related to an iron-ore mine operated by Baffinland Iron Mines Corporation; how this increase in vessel traffic may impact narwhal is currently unknown. Cortisol is a stress response hormone and a stress indicator in marine mammals. This study evaluated cortisol levels in narwhal blubber sampled during subsistence harvests prior to project-related vessel traffic (2000–2006), during project-related vessel traffic (2013–2019), and during a high-stress entrapment event that occurred in 2015. There was a significant increase in cortisol levels from pre- (0.81 ± 0.45 ng/g (±SE)) to during (1.81 ± 0.48 ng/g (±SE)) project-related vessel traffic (over 100% higher), and both were significantly lower than cortisol levels from animals sampled during an entrapment event (10.52 ± 0.59 ng/g (±SE)). Increased vessel traffic, changing ice conditions, altered Arctic food webs, increased predation pressure from killer whales, and cumulative impacts from these sources likely all contribute to increased stress levels for narwhals. Thus, there is a need for continued monitoring of stress responses (i.e., cortisol levels) and other health indicators in narwhals to understand how individual fitness and the population will be impacted over time.

Salinity, Temperature and Ammonia Acute Stress Response in Seabream (Sparus aurata) Juveniles: A Multidisciplinary Study.

Simple SummaryGilthead seabream (Sparus aurata) is a teleost fish of great relevance in marine aquaculture, especially in the Mediterranean area and one of the most important farmed food marine species in Europe. Nevertheless, in captivity fish are usually exposed to stressful conditions, with a consequent negative impact on animal welfare and growth. The principal goal of this study was to shed light on the acute stress response of gilthead seabream juveniles exposed to different stressors using a multidisciplinary approach. For this purpose, gilthead seabream have been exposed to three different stress tests (temperature, salinity, and ammonia changes) and several laboratory techniques have been used to evaluate their growth and stress response. Results revealed that all the tested stressors had an impact on fish growth and health, particularly thermic and chemical exposure, whereas salinity seems to have a minor effect since this species can efficiently face with extreme variations in environmental salinity. The present work aimed to obtain relevant information on acute stress response of gilthead seabream to be used for improving farming condition and ensuring fish welfare.The present study aimed to investigate the acute response of gilthead seabream (Sparus aurata) juveniles exposed to temperature, salinity and ammonia stress. Radioimmunoassay was used to evaluate cortisol levels, whereas insulin-like growth factors (igf1 and igf2), myostatin (mstn), heat-shock protein 70 (hsp70) and glucocorticoid receptor (gr) gene expression was assessed trough Real-Time PCR. The presence and localization of IGF-I and HSP70 were investigated by immunohistochemistry. In all the stress conditions, a significant increase in cortisol levels was observed reaching higher values in the thermic and chemical stress groups. Regarding fish growth markers, igf1 gene expression was significantly higher only in fish subjected to heat shock stress while, at 60 min, igf2 gene expression was significantly lower in all the stressed groups. Temperature and ammonia changes resulted in a higher mstn gene expression. Molecular analyses on stress response evidenced a time dependent increase in hsp70 gene expression, that was significantly higher at 60 min in fish exposed to heat shock and chemical stress. Furthermore, the same experimental groups were characterized by a significantly higher gr gene expression respect to the control one. Immunostaining for IGF-I and HSP70 antibodies was observed in skin, gills, liver, and digestive system of gilthead seabream juveniles.

Parameters of lipid and oxidative-antioxidant status in persons aged 18-23 from radiation-contaminated areas under conditions of moderate physical activity

Background and Study Aim. There is a significant amount of data on the stressful effects of exercise, which contain conflicting results. Some publications testify to the adaptive processes and the benefits of optimized exercise for various physiological systems, some deny such an effect. Much controversial is the question of combination the physical exercises of different intensity with other stressors. The purpose of the study: to analyze the parameters of lipid metabolism and oxidative-antioxidant system in persons aged 18-23 who lived in territories with different radioecological status, under conditions of moderate physical activity during exercise. Material and Methods. There were examined 50 students from relatively ecologically clean areas (control group) and 50 students from the IV radiation zone (experimental group). The radiation zone is selected by the dosimetry of soil contamination with 137Cs isotopes after the Chornobyl catastrophe. Age of the examined is 18-23 years. Within the framework of the experimental group there were formed two subgroups: the main group for physical training classes (without signs of morphological-functional disorders) and the group for therapeutic physical training classes (TPTC, persons with signs of vegetative-vascular dystonia syndrome). For the control and experimental main group, classes contained all the planned exercises due to the standard curriculum. The program included a combination of aerobic and strength exercises of moderate intensity. For students with signs of vegetative-vascular dystonia, teachers used specially designed therapeutic exercise complexes. The first analysis of parameters was carried out the day before physical training classes, the second one – immediately after the class. Results. Higher levels of total cholesterol and its lipoprotein fractions (LDL-C and HDL-C), triglycerides, oxidative stress index are detected in the experimental group compared to the control group. At the same time lower levels of sulfhydryl groups (SH) were marked. The absence of statistically significant changes in the analyzed parameters in the control group and the experimental therapeutic group after physical exercises is shown in the study. There were evident tendencies of ceruloplasmin level increase in the control along with the absence of such trends in persons with signs of vegetative-vascular dystonia syndrome. This led to the formation of a significant difference between groups for this antioxidant. There is a significant increase in cortisol level and oxidative stress index in the main group of students from radiation contaminated areas. Conclusions. Potentiation of various stress factors in persons who experienced the prolonged exposure to Chornobyl accident reduces the adaptive potential of homeostatic systems. This eliminates the optimization of lipid metabolism and oxidative-antioxidant system through moderate exercise. Exercise therapy does not cause a pronounced stress effect.

Stress and long-term memory retrieval: a systematic review.

Introduction The experience of stressful events can alter brain structures involved in memory encoding, storage and retrieval. Here we review experimental research assessing the impact of the stress-related hormone cortisol on long-term memory retrieval.Method A comprehensive literature search was conducted on PubMed, Web of Science and PsycNet databases with the following terms: “stress,” “long-term memory,” and “retrieval.” Studies were included in the review if they tested samples of healthy human participants, with at least one control group, and with the onset of the stress intervention occurring after the encoding phase and shortly (up to one hour) before the final memory test.Results Thirteen studies were included in the qualitative synthesis (N = 962) and were classified according to the time elapsed between stress induction and memory retrieval (stress-retrieval delay), the stress-inducing protocol (stressor), the time of day in which stress induction took place, sex, and age of participants. Most studies induced stress with the Trier Social Stress Test (TSST) between 15 and 25 minutes before the final memory (mostly recall) test and showed significant increases in cortisol levels and memory impairment.Discussion The reviewed studies indicate that stress does impair retrieval, particularly when induced with the TSST, in the afternoon, up to 45 minutes before the onset of the final memory test, in healthy young men. These results may inform future research on the impact of stress-induced cortisol surges on memory retrieval.

Effects of ammonium sulfate on stress physiology and innate immunity of Western mosquitofish (Gambusia affinis).

Fertilizers increase yield of crops but may have unintended negative effects on fish as a byproduct of runoff into bodies of freshwater. The objective of this study was to determine if environmentally relevant concentrations of an ammonium fertilizer impacts stress and innate immunity in Western mosquitofish (Gambusia affinis). The mosquitofish were exposed to different concentrations of ammonium sulfate fertilizer: 0 ppm, 40 ppm, and 80 ppm. To test the effects of ammonium sulfate on stress physiology, cortisol released into water by individual fish was collected after 1 week of exposure and again after 2 weeks of exposure and quantified with an enzyme immunoassay. Cortisol levels in the 0-ppm group were not significantly different over the course of the study, but we found a significant increase in cortisol levels in the fish exposed to 40 ppm and 80 ppm. We found reduced survival in fish from the 40 ppm and 80 ppm of ammonium sulfate groups compared with the 0-ppm group. We also used blood samples to complete a lysozyme assay as a measure of innate immune defense. Higher concentrations of ammonium sulfate correlated with significantly lower lysozyme activity in the fish. Overall, our results suggest that relatively low amounts of ammonium sulfate runoff into bodies of water are likely to have negative sublethal and lethal effects on small fishes.

Increasing Deactivation of Limbic Structures Over Psychosocial Stress Exposure Time

BackgroundUnderstanding the interplay between central nervous system and hypothalamic-pituitary-adrenal axis responses to stress in humans is assumed to be essential to contribute to the central question of stress research, namely how stress can increase disease risk. Therefore, the present study used a neuroimaging stress paradigm to investigate the interplay of 3 stress response domains. Furthermore, we asked if the brain’s stress response changes over exposure time. MethodsIn a functional magnetic resonance imaging study, changes in brain activation, cortisol levels, affect, and heart rate in response to an improved ScanSTRESS protocol were assessed in 67 young, healthy participants (31 females). ResultsStress exposure led to significant increases in cortisol levels, heart rate, and negative affect ratings as well as to activations and deactivations in (pre)limbic regions. When cortisol increase was used as a covariate, stronger responses in the hippocampus, amygdala, medial prefrontal cortex, and cingulate gyrus were observed. Responses within the same regions predicted negative affect ratings. Remarkably, an increasing deactivation over the two ScanSTRESS runs was found, again, in the same structures. A reanalysis of an independent sample confirmed this finding. ConclusionsFor the first time, reactions in a cluster of (pre)limbic structures was consistently found to be associated with changes in cortisol and negative affect. The same neural structures showed increasing deactivations over stress exposure time. We speculate that investigating possible associations between exposure-time effects in neural stress responses and stress-related interindividual differences (e.g., chronic stress) might be a promising new avenue in stress research.

Behavioral and Endocrine Alterations to Partner Interactions and Offspring Care during Periods of Conflict

Biparental care has evolved to ensure successful rearing of offspring. However, separation during periods of care can lead to conflicts that might negatively impact pair bonds and offspring care. In this study, pair-bonded convict cichlids (Amatitlania nigrofasciata) were observed for changes in behavior toward their partners and offspring before and after a period of separation. Males and females were designated either as a Resident (remain with offspring) or Removed (separated from partner and offspring for 5 days) individual. Behaviors between partners and toward offspring were measured before and after separation, and compared to the levels of behavior of control pairs (never separated), as well as individuals introduced to a novel partner instead. Cortisol levels of Resident male and female A. nigrofasciata were assayed using water-borne hormone collection before and after separation. Aggression between pair bond members did increase following reintroduction, but did not lead to the termination of pair bonds. Resident females showed more aggression to novel partners than Resident males. Offspring care decreased in both Resident and Removed females. Experimental pairs decreased the amount of time spent interacting with intruders. Cortisol levels were significantly higher among experimental pairs compared with control pairs that did not experience a separation. Females (both control and experimental) showed small, yet significant increases in cortisol levels, while both control and experimental males did not. These results suggest that while pair bonds appear resilient, prolonged separations influence pair bond and parental care dynamics, both behaviorally and hormonally, and require pairs to re-establish roles, resulting in less time caring for offspring.

Serum Cortisol Levels Modifications in Patients with Depression and Irritable Bowel Syndrome

The correlations between depression and stress are quite accepted nowadays, as well as the fact that cortisol levels could also represent fundamental risk factors for major depressive disorder. However, when it comes to the modifications of cortisol levels in depression, the results are controversial. Same goes for the cortisol modifications in irritable bowel syndrome (IBS), which is a functional digestive disorder characterized by a strong biopsychological component, being highly influenced or exacerbated by stressful stimuli. Thus, in the present report we were interested in seeing if there are any serum cortisol levels variations in patients with depression and irritable bowel syndrome, by looking at cortisol modifications in two different groups of patients: a control group with major depression disorder and another study group composed by major depression disorder + IBS patients. Thus, our data presented here are suggesting that there is a significant increase in cortisol levels in the morning serum of the patients with major depression disorder + IBS, as compared to the group having only depression. The results presented here could have an important relevance in the context of managing the stress-related factors in the pathological entities described above.