Determination Of Cortisol Concentrations Research Articles

Friend or Family? Social Recognition and Physiological Stress in the Self‐Fertilizing Mangrove Rivulus Fish (Kryptolebias marmoratus)

Social behavior has the capacity to influence how animals respond to environmental stress. Living in social groups may be beneficial to animals as it can reduce predation risk and provide foraging benefits. Advantages may be further enhanced if animals associate with related individuals (kin), with individuals of the same phenotype and/or with familiar conspecifics, regardless of relatedness. On the other hand, grouping may incur costs if there is competition for resources or increased aggression. Given the potential influence of sociality on physiological responses to stress, it is important to understand an animal's social behavior and if certain social interactions result in physiological stress. The mangrove rivulus is a tropical, self‐fertilizing fish that forms isogenic lineages, providing a model fish with a natural and extreme form of kin. Using distinct strains of rivulus originating from Belize and Honduras, we predicted that rivulus would use both relatedness and familiarity as cues to recognize conspecifics. We used a choice chamber and in two separate experiments, gave focal fish of each strain the choice between related or familiar stimulus fish. We took water samples to determine cortisol concentrations, as we predicted that association with non‐kin and/or unfamiliar fish would be stressful and result in increases is the stress hormone. We found no significant differences in the proportion of time either lineage spent with familiar or related conspecifics. We further analysed association time for aggressive behaviour as we predicted that rivulus would be less aggressive to both familiar and related conspecifics. Interestingly, we determined that the Belize lineage is not aggressive towards related or unrelated individuals whereas the Honduran lineage is aggressive to unrelated conspecifics only. Collectively, our data suggest that rivulus detect conspecifics using both familiarity and relatedness; kin discrimination is not universal and appears to have a genetic basis. My further analyses will determine whether or not association with non‐kin and/or unfamiliar individuals is physiologically stressful.Support or Funding InformationResearch supported by APS UGSRF and Mount Allison University. Cortisol analysis is in collaboration with Dr. Ryan Earley, University of Alabama. Research supervised by Dr. Suzie Currie.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Link between children’s hair cortisol and psychopathology or quality of life moderated by childhood adversity risk

The hypothalamus-pituitary-adrenal axis (HPAA) and its end product, the glucocorticoid cortisol, has been shown to be associated with psychopathology. Determining cortisol concentrations in hair (HCC) allows the investigation of long-term HPAA-activity. There is a significant scarcity of studies investigating the link between HCC and psychopathology and quality of life in child and adolescent samples. In addition, as the HPAA constitutes a feedback system enabling adaption to environmental demands, it is important to consider the socio-environmental context that the children grow up in. We therefore investigated the associations between child HCC and psychopathology/quality of life and compared these links in two groups of five to 12-year-olds: children living with mothers who report experiences of early life maltreatment (ELM) (high-risk group) and children whose mothers did not report any ELM (low-risk group). We expected that, under conditions of a high-risk environment, elevated HPAA-functioning would be associated with low levels of psychopathology and high levels of quality of life in children. Under low-risk conditions, elevated HPAA-functioning would be associated with high levels of psychopathology and low levels of quality of life in children. For the complete sample of N = 130 children, three-months HCC did not significantly predict child psychopathology or quality of life. However, there was a significant moderating effect of group membership: In the high-risk group, high levels of HCC were significantly associated with high levels of self-reported quality of life. In the low-risk group, there was no association between HCC and self-reported quality of life. For child psychopathology, in the low-risk group, high levels of HCC were significantly associated with high levels of teacher reported behavior problems, whereas in the high-risk group, the association did not reach significance. Our results underline the importance of accounting for the social environment children grow up in when investigating the link between HCC and child psychopathology and quality of life.

The stress response of 6-month-old horses to abrupt weaning is influenced by their sex

Abstract In this study, we investigated differences in the immediate response of male and female foals to weaning. A total of 22 foals (11 male and 11 female) of 6 months of age were weaned abruptly from their dams but remained in their familiar foal groups. Body weight was determined. Behavior of foals was observed from 2 days before to 7 days after weaning. Saliva samples for determination of cortisol concentration were collected from 2 days before to 7 days after weaning at 6 AM, 0:30 PM, and 7 PM. On the day of weaning, saliva was collected from 1 hour before until 4 hours after weaning at 30-minute intervals. Heart rate and heart rate variability were monitored. Weaning resulted in higher weight loss in female than in male foals ( P P P P P P P P P P

Effect of maternal exercise on calf dry matter intake, weight gain, behavior, and cortisol concentrations at disbudding and weaning

The objective of this study was to determine the effect of maternal physical activity during late gestation on calf dry matter intake, weight gain, behavior, and cortisol concentration during disbudding and weaning. Fifty-five Holstein and 5 Jersey × Holstein crossbred calves were enrolled into the study during gestation. Calves were born from pregnant, nonlactating Holstein (n = 58) and Jersey × Holstein crossbred (n = 2) dairy cows. Cows were assigned to either confinement (n = 20 cows; 13 female calves, 7 male calves), exercise (n = 20 cows; 8 female calves, 12 male calves), or pasture (n = 20 cows; 11 female calves, 9 male calves) treatments at dry-off from January to November 2015. Enrollment in treatment was balanced by parity (1.8 ± 0.9), projected mature-equivalent fat-corrected milk (13,831 ± 2,028 kg/lactation), dam breed, and projected calving date. Cows assigned to confinement remained in the pen throughout the dry period. Cows assigned to exercise were walked 5 times/wk at a targeted 1.5 h at 3.25 km/h. Cows assigned to pasture were turned out 5 times/wk for a targeted 1.5 h/d. Treatments were terminated on the expected due date or at signs of calving. Calves were removed from cows immediately once observed by farm staff and subsequently weighed and moved into a straw deep-bedded hutch. Data loggers were attached to the rear fetlock of each calf -3 d to +6 d relative to disbudding and weaning to monitor changes in lying behavior. Calves were weighed on d -7, -5, -3, -1, 0, 1, 3, 5, and 7, and grain was weighed the 7 d preceding and following disbudding and weaning. Blood was collected 24 h before and 0, 1, and 4 h after disbudding and d -1, 0, 1, and 2 relative to weaning to determine cortisol concentrations. Data were analyzed using mixed linear model in SAS (SAS Institute Inc., Cary, NC). Calf weight gain decreased the day after disbudding and calves tended to have elevated cortisol concentrations 1 h after disbudding, regardless of maternal treatment. Calf weight gain decreased the day of and after weaning; calves had elevated cortisol concentrations the day after weaning, regardless of treatment. Behavior did not differ by treatment at disbudding, but calves from pasture cows lay down for less time compared with confinement and exercise maternal treatments and less frequently than exercise maternal treatments at weaning. More research investigating the significance of lying time and restlessness around stressful events is needed to further understand the implications of such behavioral responses.

Cortisol concentration of regrown hair and hair from a previously unshorn area in dairy cows

This study determined cortisol concentrations in hair that had grown for one month and in hair from a previously unshorn area and examined the effects of calendar month, pregnancy and illness on hair cortisol concentrations in dairy cows. The study was conducted over a one-year period using 27 cows. Electric clippers were used to collect two hair samples per cow each month. The first sample (A sample) consisted of hair that had grown for one month in a pre-clipped area and the second sample (B sample) comprised all hair from a previously unshorn area. Liquid chromatography tandem mass-spectrometry was used for cortisol measurement. The overall mean concentrations for A and B samples did not differ. Cortisol concentrations of A samples were significantly higher in the winter (0.86±0.37pg/mg) than in the fall (0.67±0.33pg/mg). The hair cortisol concentration in A samples increased during pregnancy and the maximum concentration of 1.40±1.08pg/mg hair in the month of calving was significantly higher than the concentration measured in the first month (0.66±0.32pg/mg). The findings show that the effect of short-term stressors such as parturition on hair cortisol concentrations are more easily detected in hair that has grown for one month than in hair from a previously unshorn area.

Extended low-dose dexamethasone suppression test for diagnosis of atypical Cushing's syndrome in dogs

The purpose of this study was to evaluate extension of the low-dose dexamethasone suppression (LDDS) test from 8 h to 12 h to detect possible hypercortisolemia associated with atypical hyperadrenocorticism (AHAC). Twelve client-owned dogs were enrolled in the study: 6 healthy dogs (group 1) and 6 dogs with suspected AHAC (group 2). Baseline EDTA plasma samples were collected for endogenous ACTH determination using an immunoradiometric assay. Serum samples were collected before and at 4, 8, 10, and 12 h post-administration of 0.01 mg/kg dexamethasone IV for cortisol concentration determination via chemiluminescent assay. Mean endogenous ACTH concentration did not differ between groups (group 1: 22.4 pg/mL, group 2: 20.0 pg/mL; P > 0.2). Mean baseline cortisol concentration also did not differ significantly between groups (group 1: 3.03 μg/dL, group 2: 4.95 μg/dL; P > 0.2) nor was there any difference in mean cortisol concentration between the groups at any other time point (P > 0.2). The cortisol concentration from 1 dog in group 2 suppressed to 0.7 μg/dL at 8 h but increased to 1.5 μg/dL at 10 h and 3.7 μg/dL at 12 h post-dexamethasone. Based on results of this study, use of an extended LDDS test could not differentiate between healthy dogs and dogs with AHAC. Diagnosis of AHAC should continue to be based on prior established criteria until new testing has been identified.

Hypothalamic-pituitary-adrenal and cardiac autonomic responses to transrectal examination differ with behavioral reactivity in dairy cows

Behavior, hypothalamic-pituitary-adrenal axis, and cardiac autonomic nervous system (ANS) activity were evaluated in response to transrectal examination in nonlactating Holstein-Friesian cows with different behavioral reactivity. According to behavioral reactions shown to the procedure of fixing the heart rate (HR) monitors, the 20 cows with the highest and the 20 cows with the lowest behavioral reactivity were involved in the study (high responder, n=20; and low responder, n=20, respectively). Activity of the ANS was assessed by HR and HR variability parameters. Blood and saliva were collected at 5 min before (baseline) and 0, 5 10, 15, 20, 30, 40, 60, and 120 min after the examination to determine cortisol concentrations. The examination lasted for 5 min. Cardiac parameters included HR, the root mean square of successive differences between the consecutive interbeat intervals, the high frequency (HF) component of heart rate variability, and the ratio between the low frequency (LF) and HF parameter (LF/HF). Following the examination, peak plasma and saliva cortisol levels and the amplitude of the plasma and saliva cortisol response were higher in high responder cows than in low responders. Areas under the plasma and saliva cortisol response curves were greater in high responder cows. Plasma and salivary cortisol levels correlated significantly at baseline (r=0.91), right after examination (r=0.98), and at peak levels (r=0.96). Area under the HR response curve was higher in low responder cows; however, maximum HR and the amplitude of the HR response showed no differences between groups. Minimum values of both parameters calculated for the examination were higher in high responders. Following the examination, response parameters of root mean square of successive differences and HF did not differ between groups. The maximum and the amplitude of LF/HF response and area under the LF/HF response curve were lower in low responder cows, suggesting a lower sympathetic activation of the ANS. Although changes in behaviors indicated that the procedure was painful for the animals, no differences were observed either in vocalization or in attendant behavior between groups during the examination. Our results demonstrate that behaviorally more reactive animals exhibit increased plasma and salivary cortisol concentrations and higher cardiac autonomic responsiveness to transrectal examination than less reactive cows. Salivary cortisol may substitute for plasma cortisol when assessing response of cattle to stress.

Effect of Raising Beef Cattle in the Double Shaded House on Their Fattening Performance in Thailand

5 Abstract: The fattening performance of beef cattle improved by raising in double shaded house in Thailand. Eight fattening crossbred beef cattle, (50 to 75% Charolais crossbred cattle), were randomly assigned into two groups. They were raised under the management of small holders in Pon-Yang-Kham Co-operative in Sakon Nakhon, Thailand. In group 1, cattle were allocated in normal house which had one shade of zinc metal roof without ceiling and it was open house. In group 2, cattle were allocated in double shaded house which had one lower shade of zinc metal roof at the under and one upper shade of black plastic slant over the latter roof. After preliminary experimental period for 2 weeks, the temperature and relative humidity in houses were recorded and blood samples were collected on day 0, 90 and 180 of experimental duration to determine cortisol concentration. Changes in general physiology (rectal temperature, pulse rates, respiration rates, heat tolerance co-efficiency; HTC and sweating rates) and hematology (hematocrit (%), hemoglobin, blood glucose and blood urea nitrogen and cortisol concentration) were recorded through the experimental period. The temperature humidity index (THI) affected on the general physiological changes of cattle between group 1 and group 2 which were highly significant different (p<0.01) viz. rectal temperature (39.36 and 39.09°C), pulse rates (72.24 and 64.48 breaths/min), respiration rates (50.42 and 44.20 b/t), HTC (80.60 and 88.20%) and sweating rates (1.060 and 840 (mL/m /h), respectively and hematology and cortisol 2 concentration in blood serum of fattening beef cattle in both groups were increased (p<0.01). The fattening performance of cattle between group 1 and group 2 were significant different (p<0.05) as follows; final weight (722.62 and 748.20 kg), ADG (656.15 and 732.50 g/d), dressing percentage (54.24 and 60.40%) and marbling (3.51 and 3.84%). We suggest that raising beef cattle in a modified double shaded house is capable of improving fattening performance in the semi-tropical countries.

Effects of castration method and frequency of intramuscular injections of ketoprofen on behavioral and physiological indicators of pain in beef cattle1

Two experiments were conducted to determine the effect of a single or multiple intramuscular (i.m.) injection of ketoprofen and castration technique on physiological and behavioral indicators of pain in beef calves. A total of 150 bull calves (284.8 ± 22.7 kg BW) were used in both experiments, each 1 conducted as a 3 × 2 factorial design, where main factors included castration technique--no castration (CT), surgical (SU), or band (BA)--and drug administration--physiological solution (PS) or i.m. injection of ketoprofen (KP; 3 mg Anafen/kg BW) in the neck of calves. Animals were weighed weekly during the experiment to calculate ADG. Behavioral responses indicative of pain and discomfort during the castration procedure were documented using a visual analog score (VAS) by an experienced observer who was blind to the treatments. Movements of the animals in the chute during castration were quantified using a strain gauge system mounted on the head gate to evaluate the escape response of the cattle. Pens were equipped with an automated feed bunk monitoring system enabling feed intake and feeding behavior to be continuously monitored for each individual. Thermographic images of the scrotal area were evaluated 24 and 0.5 h before castration, 0.5, 1, 24, 48, and 270 h postcastration, and weekly thereafter until the end of the trial. Blood samples were obtained postcastration to evaluate changes in total white blood cell (WBC) count and neutrophil-to-lymphocyte (N:L) ratio. Saliva samples were taken 24 and 0.5 h before castration, immediately after castration, and 0.5, 1, 2, 5, 24, and 48 h and then 5, 7, and 14 d after castration to determine cortisol concentration. Scrotal temperature, VAS, total WBC, N:L ratio, salivary cortisol, mobility, and pressure exerted in the chute were greater (P < 0.05) and ADG and feed intake were lower (P < 0.05) in SU than in CT animals within the first week after castration. Also, BA calves had a greater (P < 0.05) scrotal temperature around wk 4 after castration and a lower feed intake and ADG at wk 2 and 3 and wk 6 and 7 after castration, respectively, compared to CT. Treatment KP had limited effects on reducing the indicators of pain associated with SU or BA, suggesting that further studies will be needed to assess the posology of the i.m. administration of ketoprofen to improve the consistency of its effects as a pain mitigation strategy after castration.

Changes in salivary and plasma cortisol levels inPurebredArabian horses during race training session

Physical activity and stress both cause an increase in cortisol release ratio. The aim of this study was to evaluate the use of saliva samples for the determination of cortisol concentrations indicating the work-load level in horses during race training. Twelve Purebred Arabian horses aged 3-5 years were studied during the routine training session. After the warm-up, the horses galloped on the 800 m sand track at a speed of 12.8 m/s. Three saliva samples, and three blood samples were collected from each horse. Both types of samples were taken at rest, immediately after return from the track and after 30 min restitution. The concentrations of blood lactic acid (LA), and cortisol in saliva and plasma samples were measured and analyzed. Blood LA, plasma and salivary cortisol levels increased significantly after exercise (P < 0.05). Salivary cortisol concentration determined 30 min after the exercise correlated significantly with plasma cortisol level obtained immediately after exercise (P < 0.05) as well as measured 30 min after the end of exercise (P < 0.05). The determination of cortisol concentration in saliva samples taken from racehorses 30 min after the end of exercise can be recommended to use in field conditions to estimate the work-load in racehorses.

Seasonal pattern of salivary cortisol secretion in the greater one-horned rhino(Rhinoceros unicornis)

AbstractThe Indian rhinoceros or greater one-horned rhino(Rhinoceros unicornis)is listed as vulnerable by the IUCN Red List of Threatened Species and, therefore, captive individuals have been subject to the European Endangered Species Programme since 1990. Enhancement of welfare is key in ensuring the breeding success of this species in captivity. Salivary cortisol has been recently used to assess welfare of captive and free-ranging animals. Nevertheless, rhythms of cortisol secretion may fluctuate throughout the year and therefore, knowledge of the circannual pattern of cortisol secretion is essential to evaluate the physiological significance of seasonal variations of cortisol levels as an indicator of stress in animals. Here, we analyse monthly differences in cortisol secretion in two Indian rhinoceros. Saliva samples of two rhinoceros were collected and analysed by radioimmunoassay for the period of one year to determine cortisol concentrations. We found a seasonal pattern of salivary cortisol secretion. The highest cortisol concentrations were found in August and decreased until reaching a nadir in January. Cortisol concentrations in these two animals showed a correlation with temperature and visitor numbers but it is not possible to draw conclusions from this study as to whether the variation in cortisol was due to these or other factors.

Salivary Cortisol Concentration in Exercised Thoroughbred Horses

Both physical activity and stress result in an increase in plasma cortisol level. The measurement of cortisol in plasma requires taking blood samples, which is stressful itself. Therefore, the aim of this study was to evaluate the use of saliva sampling for the determination of cortisol concentrations, indicating the intensity of exercise in horses during race training. Twelve Thoroughbred horses aged 2-3 years were examined during their speed training sessions. The horses galloped on the 1,200-m sand track at a speed of 14.4-15.3 m/s. Three saliva samples and three blood samples were collected from each horse. Both types of samples were taken when the horse was at rest, immediately after returning from the track and 30 minutes after the end of exercise. Blood lactic acid (LA) concentration was determined using the enzymatic cuvette test. The concentrations of cortisol in saliva and plasma samples were measured by enzyme immunoassay methods. Statistically significant correlations were found between salivary cortisol level determined 30 minutes after the end of exercise and blood LA concentration obtained immediately after exercise (P = .003) and between salivary and plasma cortisol levels measured 30 minutes after the end of training session (P = .015). The measurement of cortisol concentration in saliva samples taken from race horses 30 minutes after the end of exercise can be recommended for use in practice under field conditions to estimate the level of relative intensity of exercise in race horses.

Comparison of innate immune responses and somatotropic axis components of Holstein and Montbéliarde-sired crossbred dairy cows during the transition period

Objectives were to compare parameters related to innate immune responses and somatotropic axis of Holstein (HO) and Montbéliarde (MO)-sired crossbred cows during the transition from late gestation to early lactation. Cows (40 HO and 47 MO-sired crossbred) were enrolled in the study 45d before expected calving date (study d 0=calving). Polymorphonuclear leukocytes (PMNL) isolated from blood samples collected weekly from study d −7 to 21 and on study d 42 were used for determination of percentage of PMNL positive for phagocytosis (PA+) and oxidative burst (OB+), intensity of PA and OB, percentage of PMNL expressing CD18 (CD18+) and L-selectin (LS+), and intensity of CD18 and LS expression. Blood was sampled weekly from study d −7 to 14 and on study d 28, 42, and 56 for determination of insulin, growth hormone (GH), leptin, and insulin-like growth factor (IGF)-1 concentrations. Blood sampled weekly from study d −14 to 21 and on study d 42 was used to determine cortisol concentration. Liver biopsies were performed on study d −14, 7, 14, and 28 for determination of mRNA expression for insulin receptor B (IRB), total GH receptor (GHRtot), GHR variant 1A (GHR1A), and IGF-1. Data were analyzed by ANOVA for repeated measures or by ANOVA using the GLM procedure of SAS (SAS Institute Inc., Cary, NC). Intensity of CD18 expression was greater in PMNL from crossbred cows compared with PMNL from HO cows [1,482.1±82.3 vs. 1,286.6±69.8 geometric mean fluorescence intensity (GMFI)]. Furthermore, among HO cows, the percentage of PA+ PMNL on study d −7 (64.4±5.2%) tended to be greater than on study d 0 (57.1±5.1%), but no differences in percentage of PA+ PMNL between study d −7 and 0 were observed in crossbred cows. Similarly, intensity of PA in PA+ PMNL from HO cows decreased from study d −7 to 0 (4,750.6±1,217.0 vs. 1,964.7±1,227.9 GMFI), but no changes in intensity of PA in PA+ PMNL from crossbred cows were observed. On study d 0, intensity of PA tended to be reduced in PA+ PMNL from HO cows compared with PA+ PMNL from crossbred cows (1,964.7±1,227.9 vs. 4,688.1±1,271.8 GMFI). Concentrations of GH (7.4±0.4 vs. 5.1±0.4 ng/mL) and cortisol (9.5±0.8 vs. 7.1±0.8ng/mL) were greater for HO than for crossbred cows. Crossbred cows had improved innate immune responses compared with HO cows, as determined by a lack of decrease in intensity of PA on the day of calving, which may result in improved health. Furthermore, HO cows appeared to be less sensitive to the negative feedback of IGF-1 on GH secretion because cows from both breeds had similar IGF-1 concentrations but MO-sired crossbred cows had greater GH concentrations.

Hypothalamic–pituitary–adrenal axis function in patients with complex regional pain syndrome type 1

An exaggerated inflammatory process is considered an important pathophysiological feature of complex regional pain syndrome type 1 (CRPS-1). The hypothalamic-pituitary-adrenal (HPA) axis serves as a negative feedback mechanism for inflammatory processes. The present study examined the HPA axis function in patients with CRPS-1 by a determination of cortisol concentrations in saliva. Three sets of saliva samples were sequentially collected from 24 patients with CRPS-1 during medication (on-Med), 72 h after stopping medication (off-Med) and 8h after the oral administration of 1mg dexamethasone. One set of saliva samples was collected from healthy controls. The cortisol awakening response (CAR) and diurnal cortisol decline (DCD) were used as indices for HPA axis function. Cortisol levels during the post-awakening period in patients were increased following withdrawal of medications. The CAR during the off-Med condition was disappeared after administration of dexamethasone. Among the examined CRPS-related numerical variables, the frequency of spontaneous pain attacks showed relationships with the indices of HPA axis function. After classifying the patients into two subgroups, we observed that the CAR and DCD in patient who had a relatively high frequency of spontaneous pain attacks (subgroup 5 ≤) were lower and less steep than those in patient who had a relatively low frequency of spontaneous pain attacks (subgroup 0-4) for the on- and off-Med conditions. The CAR and DCD in subgroup 5 ≤ during their off-Med condition were comparable to those in controls. These results suggest that the increase in frequency of spontaneous pain attacks is associated with a reduced CAR and flattened DCD in patients CRPS-1.

Dithiobis(succinimidyl propionate) modified gold microarray electrode based electrochemical immunosensor for ultrasensitive detection of cortisol

Gold microelectrode arrays functionalized with dithiobis(succinimidyl propionate) self-assembled monolayer (SAM) have been used to fabricate an ultrasensitive, disposable, electrochemical cortisol immunosensor. Cortisol specific monoclonal antibody (C-Mab) was covalently immobilized on the surface of gold microelectrode array and the sensors were exposed to solutions with different cortisol concentration. After C-Mab binding, unreacted active groups of DTSP were blocked using ethanol amine (EA) and label-free electrochemical impedance (EIS) technique was used to determine cortisol concentration. EIS results confirmed that EA/C-Mab/DTSP/Au based biosensor can accurately detect cortisol in the range of 1 pM–100 nM. The biosensor was successfully used for the measurement of cortisol in interstitial fluid in vitro. This research establishes the feasibility of using impedance based biosensor architecture for disposable, wearable cortisol detector.

Low-Dose and High-Dose Synacthen Tests and the Hemodynamic Response to Hydrocortisone in Acute Traumatic Brain Injury

In order to identify whether low-dose (1 microg) tetracosactide (Synacthen) testing may be preferable to high-dose (250 microg) testing in the diagnosis of adrenal insufficiency in traumatic brain injury (TBI), as suggested by studies in other forms of critical illness. We retrospectively reviewed the results of modified tetracosactide tests (involving administration of both low-dose and high-dose tetracosactide) conducted for clinical indications in patients in a neurocritical care unit within 10 days of TBI. Sixty-three modified tests were included and cortisol concentrations before and after administration of tetracosactide were extracted from the hospital records. Data were also extracted regarding hemodynamic response to empirical corticosteroid therapy, based on rapid weaning from vasoactive drugs. Cortisol increments at 30 and 60 min following tetracosactide correlated well in the low-dose test (r(2) = 0.875, P < 0.0001). The mean cortisol concentration was 581 nmol/l at 30 min and 556 nmol/l at 60 min in the low-dose test. Cortisol increments following low-dose and high-dose testing correlated well overall (r(2) = 0.839, P < 0.0001), but results were discordant in 27 of 63 cases (43%) when the same diagnostic threshold was used. ROC curve analysis showed that both tests performed poorly in identifying hemodynamic steroid responsiveness (AUC 0.553 and 0.502, respectively). In the low-dose tetracosactide test, it is sufficient to determine cortisol concentrations at baseline and at 30 min. Low-dose and high-dose tests give discordant results in a significant proportion of cases when using the same diagnostic threshold. Neither test can be used to guide the initiation of corticosteroid therapy in acute TBI.

Effect of low doses of cosyntropin on serum cortisol concentrations in clinically normal dogs

To determine the lowest of 5 doses of cosyntropin (1.0, 0.5, 0.1, 0.05, or 0.01 microg/kg) administered IV that stimulates maximal cortisol secretion in clinically normal dogs. 10 clinically normal dogs. 5 dose-response experiments were performed in each of the dogs. Each dog received 5 doses of cosyntropin (1.0, 0.5, 0.1, 0.05, and 0.01 microg/kg) IV in random order (2-week interval between each dose). Serum samples for determination of cortisol concentrations were obtained before (baseline) and at 10, 20, 30, 40, 50, 60, 120, and 240 minutes after cosyntropin administration. Compared with baseline values, mean serum cortisol concentration in the study dogs increased significantly after administration of each of the 5 cosyntropin doses. Mean peak serum cortisol concentration was significantly lower after administration of 0.01, 0.05, and 0.1 microg of cosyntropin/kg, compared with findings after administration of 0.5 and 1.0 microg of cosyntropin/kg. After administration of 0.5 and 1.0 microg of cosyntropin/kg, mean peak serum cortisol concentration did not differ significantly; higher doses of cosyntropin resulted in more sustained increases in serum cortisol concentration, and peak response developed after a longer interval. Administration of cosyntropin IV at a dose of 0.5 microg/kg induced maximal cortisol secretion in healthy dogs. Serum cortisol concentration was reliably increased in all dogs after the administration of each of the 5 doses of cosyntropin. These data should be useful in subsequent studies to evaluate the hypothalamic-pituitary-adrenal axis in healthy and critically ill dogs.

Effects of a high-fiber diet and frequent feeding on behavior, reproductive performance, and nutrient digestibility in gestating sows1,2

A study was conducted to determine the effects of feeding a corn-soybean meal (control) diet vs. a corn-soybean meal-40% soybean hulls (high fiber) diet, as well as the frequency of feeding (once vs. twice daily), on the welfare and performance of gestating sows. Two hundred thirty-nine mixed-parity sows were assigned to a 2 x 2 factorial arrangement of treatments. Sows fed once daily received their entire meal at 0730, whereas sows fed twice daily received one-half of their feed allotment at 0730 and the other half at 1430. The behavior of 68 focal sows (> or = 16 sows per treatment combination) was observed on d 1 postweaning, and on d 40 and d 80 of gestation. The percentage of time standing, lying, sitting, feeding, inactive, and performing stereotypic behaviors was determined. Saliva samples were collected to determine cortisol concentrations. Sow BW and backfat depth were determined on d 0, 40, and 80 of gestation, within 24 h of farrowing, and at weaning. An energy and nitrogen digestibility study was conducted using 36 sows assigned to each of the 4 treatment combinations. Over a 24-h period, the sows fed the high-fiber diet spent less time lying (P < 0.05) than the sows fed the control diet. The frequency of feeding did not affect sow behavior measured over a 24-h period. During mealtimes, sows fed the high-fiber diet spent more time feeding (P < 0.05) than sows fed the control diet. Feeding the high-fiber diet did not affect stereotypic behavior measured over 24 h or during mealtimes. Neither diet nor feeding frequency affected salivary cortisol concentration. Sows fed the high-fiber diet gained less BW and lost backfat (P < 0.05) during gestation compared with sows fed the control diet, whereas sows fed once daily gained less BW and lost backfat (P < 0.05) compared with sows fed twice daily. Sows fed the high-fiber diet had fewer pigs born (P < 0.05) compared with sows fed the control diet. Feeding frequency had no effect on size or weight gain of litters. Sows fed the high-fiber diet exhibited lower digestibility of DM, energy, and N (P < 0.05) compared with sows fed the control diet. Feeding a high-fiber diet utilizing soybean hulls or increasing feeding frequency did not enhance the welfare of sows by reducing stereotypic behaviors nor did it improve reproductive performance.

Ziprasidone decreases cortisol excretion in healthy subjects

To determine the influence of the atypical antipsychotic ziprasidone on cortisol excretion. In a double-blind, placebo-controlled, randomized cross-over design 11 healthy male subjects were studied twice for 2 consecutive nights (N1, undisturbed sleep conditions; N2, exposure to acoustic stress) 5 days apart. Placebo or ziprasidone 40 mg was administered orally 2 h before bedtime on N1 and N2. Urine was collected during three fractionated collection periods (evening; night; morning) for the later determination of cortisol concentrations by standard radioimmunoassays. Ziprasidone decreased the total amount of cortisol excreted by 4.9 (95% CI 3.3, 6.5) microg during N1 and by 10.8 (95% CI 5.7, 15.8) microg during N2 (P < 0.002). This effect was still detectable in the morning (P < 0.02), with decreases of 5.8 (95% CI -2.8, 14.4) microg after N1 and by 12.1 (95% CI 2.8, 21.4) microg after N2. The effect subsided in the evening. A significant intervention-condition interaction (P < 0.02), was found. The significant increase in cortisol excretion during acoustic stress observed with placebo was absent after treatment with ziprasidone. The significant decrease in nocturnal cortisol excretion following ziprasidone reflects a decreased activity of the HPA-axis in healthy subjects. This effect may be an important contributor to the mode of action of ziprasidone in different patient populations, particularly in the treatment of depression and in cognitive impairment in schizophrenia.

Increased Cortisol Levels in Human Umbilical Cord Blood Inhibit Interferon Alpha Production of Neonates

Immunosuppressive effects of corticosteroids are generally known, but the mechanisms influencing the immune system are poorly understood. However, a correlation between cortisol levels and cytokine production has been reported by several investigators. In the present study we determined cortisol concentrations in human umbilical cord blood. Cord blood samples from healthy and normal term infants born by vaginal delivery and blood samples from healthy adult donors, respectively, were analysed. Our data revealed significantly increased cortisol levels in cord blood. In contrast, samples derived from infants born by caesarian section seem to be normal. Further experiments were performed to analyse the influence of cortisol on the production of interferon (IFN) a. Therefore, peripheral blood mononuclear cells (PBMC) were separated from peripheral blood of healthy adult volunteers. Cortisol was added to a final concentration of 30 pg/dl as measured in cord blood. Following stimulation with Newcastle disease virus (NDV) the IFN-(x release was 50 to 60% reduced compared to untreated controls. These data suggest that increased levels of cortisol in cord blood might influence the IFN-CC response of newborns. We propose that cortisol levels increase transiently after birth and may alter several physiological as well as immunological reactions. Since cord blood is commonly used to investigate features of the neonatal immune system, different behaviour as a result of temporarily increased cortisol concentrations should be considered.