Medicare beneficiary complaints about quality of care

This study examined all Medicare beneficiary complaints about quality of care submitted to the California Peer Review Organization (PRO) over 18 months. The complaint rate was low, and a medical record review by the PRO only confirmed 13% of the complaints. Managed Care Organization (MCO) members filed significantly more complaints about denial and/or delays in receiving services and the failure to refer to specialists. Fee-for-service complaints focused on inpatient hospital services, particularly premature discharge, discharge planning, admission necessity, and unnecessary tests. The PRO review process took over 7 months, and the findings were generally not released to the complainants.

Postnatal handling does not attenuate hypothalamic-pituitary-adrenal hyperresponsiveness after prenatal ethanol exposure

BACKGROUND

Prenatal ethanol exposure results in hypothalamic-pituitary-adrenal (HPA) hyperresponsiveness to stress in the adult animal. In contrast, an early environmental manipulation, termed "postnatal handling," has been shown to result in decreased and/or less prolonged HPA activity in response to moderate stressors throughout the lifespan of the animal. The effects of both prenatal ethanol exposure and postnatal handling on HPA activity may be mediated by altered feedback regulation of the HPA axis. The present study tested the hypothesis that postnatal handling could attenuate the impact of prenatal ethanol exposure on hormonal responses to stressors.

METHODS

Male and female Sprague Dawley rats from prenatal ethanol (E), pair-fed (PF), and ad libitum-fed control (C) groups were either handled (H) or nonhandled (NH) during the preweaning period and were tested at 4 to 5 months of age. Animals were subjected to a 60 min restraint stress, 3 hr after intraperitoneal injection with either saline (SAL) or a synthetic glucocorticoid, dexamethasone-21-phosphate (DEX), in order to examine HPA responsiveness after DEX blockade of endogenous HPA activity. Blood samples were collected via jugular cannulae immediately before restraint (0 min), during restraint (10, 30, and 60 min), and 30 min after the termination of restraint (90 min).

RESULTS

For both males and females, DEX administration significantly reduced plasma adrenocorticotropic hormone (ACTH) and corticosterone (CORT) concentrations compared with SAL administration. H animals showed greater suppression of HPA activity (i.e., lower ACTH and/or CORT levels) than NH animals regardless of prenatal group. In addition, E females from both the H and NH treatments showed elevated ACTH and CORT after both SAL and DEX administration, whereas H and NH E males showed elevations in ACTH and CORT only after SAL, compared with their PF and C counterparts.

CONCLUSIONS

These data extend results from previous studies that demonstrated HPA hyperresponsiveness in E animals. The finding that E females but not males exhibit elevated ACTH and CORT after DEX administration suggests that prenatal ethanol exposure results in sex-specific alterations of HPA feedback. Consistent with previous data, handling in itself reduced the HPA response to restraint stress. However, handling did not attenuate either HPA hyperresponsiveness or feedback deficits in E animals.

Characterization of the activation domains of AP-2 family transcription factors

Despite sequence variation, all AP-2 isotypes are capable of activating transcription, which indicates a functional conservation. We used this property to gain a unique insight into the structure and function of the activation motifs of AP-2 family transcription factors. We have precisely localized the activation motif of human AP-2 alpha to amino acids 52-108. Our experiments indicate that similar sequence of amino acids in all AP-2 isotypes except Drosophila AP-2 alpha harbor their activation motifs. Within this sequence, fewer than 36 residues are critical for transcription activation. Our comparison studies and site-directed mutagenic analyses show that these critical amino acids are strategically placed within this sequence. These residues are interspersed with nonessential and influential residues that vary in composition and length, indicating a structural flexibility. The Drosophila AP-2 alpha has its partly conserved activation motif in an extended region about twice the length of other AP-2 isotypes. Our results reveal essential elements of the amino acid composition of activators in general and shed new light on the mechanism of transcription activation.

Regional variation in ampicillin and trimethoprim resistance in Escherichia coli in England from 1990 to 1997, in relation to antibacterial prescribing

Over 200 hospitals in England report resistance data for bacteraemia and meningitis isolates to the Public Health Laboratory Service. We reviewed ampicillin and trimethoprim resistance rates from 1990 to 1997 for Escherichia coli, which is the species reported most frequently from these bacteraemias. Ampicillin resistance was relatively stable over time, but varied between Health Regions. The proportion of ampicillin-resistant E. coli in the East Anglia region remained </=42% in all years except one and that in the South Western region always remained <50%. At the other extreme, the proportions of ampicillin-resistant isolates in the Northern and Trent regions never fell below 59%. The prevalence of resistance to trimethoprim rose over time in most regions; again, however, the prevalence of resistant isolates was lowest in the East Anglia and South Western regions, whereas the highest resistance rates were reported from Mersey, NW Thames, NE Thames and North Western regions. These observations were related to data for community prescribing, which accounts for most ampicillin and trimethoprim use. Prescribing data for ampicillin and trimethoprim from 1987 to 1997 were obtained from the IMS-HEALTH Medical Data Index, and data for all antibacterial drugs between 1995 and 1997 from the Prescription Pricing Authority. Correlations between resistance rates and prescribing of specific antibiotics were weak, although there was some trend for regions with high total prescribing to have higher rates of ampicillin resistance. The South Western region was conspicuous both for low rates of resistance and low prescribing. Several factors may determine the lack of wider and more obvious relationships between resistance and prescribing. In particular, regions may be inappropriately large areas to test the relationship, isolates from bacteraemias may not be representative of those experiencing selection pressure in the community and the resistance data may have been distorted by nosocomial strains, although this seems unlikely with E. coli.

Effects of fetal ethanol exposure on pituitary-adrenal sensitivity to secretagogues

BACKGROUND

Rodents prenatally exposed to ethanol demonstrate hormonal hyper-responsiveness to stressors in adulthood. The present study examined the hypothesis that an increased sensitivity of the adrenal to ACTH and/or the pituitary to corticotropin releasing hormone (CRH) after dexamethasone suppression, may play a role in the hormonal hyper-responsiveness seen in fetal ethanol-exposed rats.

METHODS

Sprague-Dawley males and females from prenatal ethanol-exposed (E), pair-fed (PF), and ad libitum-fed control (C) groups were tested in adulthood (90-120 days). Testing was done in a series of two experiments carried out during the trough of the corticosterone rhythm, the time of greatest sensitivity to feedback inhibition. Twenty-four to 48 hr before testing, jugular cannulae were implanted for hormone infusion and blood sample collection. In both experiments, animals were injected intraperitoneally with dexamethasone-21-phosphate (DEX) (15 microg/100 g body weight for males or 30 microg/100 g body weight for females) 3 hr before testing to suppress endogenous hypothalamic-pituitary-adrenal (HPA) activity. Animals were given a bolus infusion of ACTH (0-0.10 mg/rat) and blood samples (0.2 cc) were drawn at 60-min intervals over 240 min for determination of plasma corticosterone (CORT) levels (Experiment 1), or were given a bolus infusion of CRH (0-20 microg/kg body wt) and samples drawn at 0, 5, 15, and 30 min for determination of plasma ACTH and CORT levels (Experiment 2).

RESULTS

As expected, sex differences in adrenal response to ACTH and pituitary response to CRH were observed; females had higher CORT and ACTH levels than males at all concentrations of ACTH and CRH. In addition, dose-response relationships between exogenously administered ACTH or CRH and plasma CORT were demonstrated; increasing concentrations of secretagogues resulted in higher and/or more prolonged CORT responses in both males and females. There were no significant differences among E, PF, and C males or females in adrenal sensitivity to ACTH. However, prenatal ethanol exposure altered pituitary sensitivity to CRH in both males and females. E and PF males demonstrated increased plasma ACTH but not CORT compared with C males, whereas E females demonstrated increased plasma ACTH and CORT levels compared with PF and C females after CRH infusion.

CONCLUSIONS

Together these data suggest that (1) E animals do not show increased adrenal sensitivity to ACTH compared with controls; (2) the insult of prenatal ethanol exposure may result in altered pituitary sensitivity to CRH after DEX suppression; and (3) there may be a sex-specific difference in sensitivity of the mechanism(s) underlying HPA hyper-responsiveness.

The effect of lactation in the post-partum arthritis of MRL-lpr/fasmice

OBJECTIVE

To investigate the effects of lactation on the post-partum arthritic flare in MRL-lpr/fas mice.

METHODS

Three groups of mice were investigated. Group 1: females whose litters were weaned at termination of the experiment; group 2: females whose litters were weaned at parturition; group 3: females who were not bred. Clinical evaluation was carried out at 5-day intervals following parturition. Blood samples were also collected during the course of the experiment and assayed for corticosterone and prolactin. Histological evaluation of the joints was assessed at day 30.

RESULTS

The incidence of swelling and erythema, the bimalleolar ankle width and the histopathology were significantly reduced by removal of the litters at parturition. This correlated well with a decrease seen in prolactin levels in these females. Corticosterone, an immunomodulatory glucocorticoid, did not play a significant role in the arthritic flare.

CONCLUSION

Our findings suggest that prolactin levels contribute to the inflammation seen in MRL-lpr/fas mice following parturition.

Effect of social housing condition on heat shock protein (HSP) expression in the Shionogi mouse mammary carcinoma (SC115)

Our previous studies have shown that social housing conditions can significantly alter the growth rate of the Shionogi mouse mammary carcinoma (SC115). The present study extended our investigations to the molecular level by examining stressor effects on the expression of a group of stress-responsive proteins, the heat shock proteins (HSPs). We hypothesized that HSP expression in SC115 cells may be altered by (a) different social housing conditions in vivo and (b) steroid hormone and growth factor exposure in vitro. Mice were reared in groups (G) or as individuals (I). Immediately following tumor cell injection, mice were rehoused from group to individual (GI), from individual to group (IG), or they remained in groups (GG). Tumor tissue was resected at 0.8 g or 3.0 g, as evidence suggests that tumor size affects HSP expression, which in turn affects proliferation. The data demonstrate that expression of HSP25, 70, and 90 was increased in tumors from mice in the IG compared to GG and GI mice, at both tumor weights examined. In addition, in IG mice, HSP90 expression was greater in 0.8 g compared to 3.0 g tumors. Under controlled culture conditions, hormones known to stimulate SC115 growth both in vivo and in vitro altered HSP expression. Physiological levels of dihydrotestosterone (DHT) and pharmacological levels of hydrocortisone (HC) upregulated expression of HSP25, whereas physiological levels of beta-estradiol (E2) upregulated expression of HSP90. These data are the first to demonstrate that a psychosocial stressor, a change in social housing condition, can induce differential HSP expression. Further, these data show that hormones that regulate SC115 tumor growth, also alter HSP expression.

Psychosocial stressors and mammary tumor growth: an animal model

Stressful life events and the ability to cope with stress may play a role in the progression of breast cancer; however, the complex relationship between stressors and tumor growth is difficult to investigate in humans. Our studies have utilized the androgen-responsive Shionogi mouse mammary carcinoma (AR SC115) in male mice to investigate the effects of social housing condition on tumor growth rates and responses to chemotherapy. We demonstrate that, depending on social housing condition, mammary tumor growth and response to chemotherapy can both increase and decrease. We have examined the possible role(s) of 1) psychosocial variables, 2) testosterone and corticosterone, hormones altered by stress and known to stimulate SC115 cells in vivo and in vitro, 3) NK cells, one of the body's first lines of defense against tumor cells, 4) stress proteins, in mediating the differential tumor growth rates observed in our model. This review discusses the investigations we have undertaken to elucidate the mechanisms through which a psychosocial stressor, social housing condition, can alter tumor growth rate.

Respiratory response to exercise in postpolio patients with severe inspiratory muscle dysfunction

OBJECTIVES

To evaluate the limiting factors of exercise performance and to analyze the respiratory strategies adopted during exercise in postpolio patients with severe inspiratory muscle dysfunction.

PATIENTS

Five patients with prior poliomyelitis associated with scoliosis and with respiratory muscle dysfunction (mean vital capacity, 1.74L [range, 1.1 to 2.4]) were studied at rest and during leg or arm cycle exercise.

METHODS

Gas exchange was examined by arterial blood gases and mass spectrometry of expired air. Ventilatory mechanics were studied by measurement of esophageal and gastric pressures.

RESULTS

Blood gases at rest were normal, except for subnormal PO2 levels in three patients. In all but one patient, ventilatory insufficiency was the limiting factor for exercise. A compensatory breathing pattern with abdominal muscle recruitment during expiration was present already at rest in three of the patients. The pressures generated by the diaphragm were below fatiguing margins, ie, levels that in healthy subjects can be sustained for at least 45 minutes.

CONCLUSIONS

The extent of ventilatory dysfunction was not evident in blood gas values at rest; however, it was revealed by blood gas values during the exercise test. Diaphragm fatigue seems to be avoided at the cost of impaired blood gases.

Chronic intermittent stress does not differentially alter brain corticosteroid receptor densities in rats prenatally exposed to ethanol

Prenatal ethanol exposure produces hypothalamic-pituitary-adrenal (HPA) hyperresponsiveness to stressors. The present study tested the hypothesis that decreased corticosteroid receptor densities at HPA feedback sites may play a role in deficient feedback inhibition and the resultant HPA hyperresponsiveness that is observed following prenatal ethanol exposure. Brains of adult Sprague-Dawley rats from prenatal ethanol (E), pair-fed (PF) and ad libitum-fed control (C) treatment groups were examined for both mineralocorticoid receptor (MR; Type I) and glucocorticoid receptor (GR; Type II) densities using a cytosolic binding assay. Experiment 1 compared the effects of chronic intermittent stress (Stress Regimen I) and corticosterone (CORT) pellet implants on hippocampal corticosteroid receptor densities in control rats. Experiment 2 determined whether exposure to Stress Regimen I would differentially downregulate and whether adrenalectomy (ADX) would differentially upregulate hippocampal corticosteroid receptors in E compared with PF and C animals. Experiment 3 examined the effects of a modified chronic intermittent stress regimen (Stress Regimen II) on corticosteroid receptor densities at several HPA feedback sites (hippocampus, prefrontal cortex, hypothalamus, and anterior pituitary) in E compared with PF and C animals. CORT pellet implants significantly downregulated hippocampal GR and MR densities in control males and females. Exposure to Stress Regimen I produced downregulation of hippocampal GRs and MRs in males comparable with that produced with CORT pellet implants, and significant downregulation of hippocampal GRs in females across all prenatal treatment groups. This stress regimen also elevated basal plasma CORT levels without concurrent changes in plasma CBG levels, and increased relative adrenal weights in both males and females. In addition, upregulation of hippocampal GRs occurred at 7 days compared with 24 h following ADX in females that had previously been exposed to this stress regimen. Following exposure to Stress Regimen II, both the downregulation of hippocampal corticosteroid receptors and the increase in basal CORT levels in males and females appear to have been abolished by the changes in housing condition during the period of chronic stress. Importantly, prenatal ethanol exposure did not differentially alter GR or MR densities at any feedback site under non-stressed conditions. Exposure to Stress Regimen II, revealed subtle effects of prenatal treatments on hippocampal GRs however it is unlikely that these changes in corticosteroid receptor densities mediated the feedback inhibition deficits observed in E animals. Together, these data demonstrate that: (1) a relatively mild intermittent stress regimen can increase basal CORT levels and downregulate hippocampal corticosteroid receptor densities (2) a seemingly small change in housing conditions during stress appears to eliminate both receptor downregulation and increase in basal CORT levels and (3) decreased corticosteroid receptor densities at HPA feedback sites in the brain do not appear to underlie the HPA hyperresponsiveness observed in E animals.

Joint surgery in Ehlers-Danlos patients: results of a survey

The Ehlers-Danlos syndrome (EDS) is a rare, hereditary, connective-tissue disorder that results in increased laxity and poor soft-tissue healing. Surgical results and complications in these patients are not well documented in the literature. The goal of the present study was to survey patients with EDS who had surgery to the musculoskeletal system and document the results of surgery and complications. Forty-four patients with EDS were surveyed regarding the complications and results of surgical procedures to the shoulder, the elbow, the knee, or the ankle. Surgical procedures were performed for pain, instability, poor range of motion, or a combination of these, totaling 214 procedures. The population surveyed in the present study demonstrates that problems of surgical procedures in EDS may be high relative to other populations without connective-tissue disorders. More study is warranted in this patient population to validate the results in a larger cohort.

Occult presentation of myotonia congenita in a 15-year-old athlete

A case of myotonia congenita in an adolescent athlete was presented. Although this is a rare condition unknown to many treating physicians, the key to diagnosis was provocation of the patient's symptoms of muscle "tightening" and "cramping" during sustained exercise. The diagnosis would have been missed in routine office examinations with the patient at rest. The stereotypic generalized myotonic signs and symptoms were provoked after the patient was asked to play 20 minutes of basketball during one of his office evaluations. The provocative or postexercise examination was critical to the diagnosis as the resting office examination was completely normal. The diagnosis was subsequently confirmed by EMG and genetic testing. Myotonia congenita should be considered in the differential diagnosis of athletes with exercise-induced muscle "stiffness" or "cramping," particularly if the course is protracted and initial examinations are unremarkable. A provocative exercise period can be used to make the diagnosis. Once the diagnosis is established, appropriate pharmacologic treatment may improve symptoms and allow return to daily activity without restriction.

Glucocorticoid fast feedback is not altered in rats prenatally exposed to ethanol

Animals exposed in utero to ethanol exhibit hormonal hyperresponsiveness to stressors in adulthood. One possible mechanism for this hyperresponsiveness is a deficit in negative feedback regulation of the hypothalamic-pituitary-adrenal axis. The present study tested the hypothesis that a deficit in the fast feedback time domain may play a role in the hormonal hyperresponsiveness in ethanol-exposed rats. Sprague-Dawley offspring from prenatal ethanol (E), pair-fed (PF), and ad lib-fed control (C) groups were tested in two experiments. Experiment 1 used a swim stress paradigm and tested animals at the trough of the corticosterone (CORT) circadian rhythm. Experiment 2 used ether stress and tested animals at the peak of the circadian rhythm. Animals were injected subcutaneously with CORT or saline and were immediately subjected to either a 5-min swim stress or a 1-min ether stress. Half the animals were terminated immediately after stress (5-min postinjection), and the rest were terminated 25 min later. Plasma levels of CORT and ACTH were assayed to determine whether E animals differed from control animals in showing a CORT-induced blunting of the ACTH response to the stressor, indicating alterations in fast feedback regulation. Injection of CORT significantly blunted the ACTH response to swim stress (experiment 1) in E, PF, and C females and males, compared with their saline-injected counterparts. There were no significant differences among groups. Similarly, CORT-injected males in E, PF, and C groups all exhibited a significantly blunted ACTH response to ether stress (experiment 2). CORT-injected C females also exhibited a significantly blunted ACTH response to ether stress, whereas E females showed an obvious CORT decrease that approached significance. However, PF females showed a clear deficit in fast feedback regulation. Together, these data suggest that: (1) CORT injection can serve as a fast feedback signal that can blunt the ACTH response to a stressor; and (2) prenatal ethanol exposure does not produce a deficit in hypothalamic-pituitary-adrenal feedback regulation in the fast feedback time domain.

Interactive effects of psychosocial stressors and gender on mouse mammary tumor growth

We have previously demonstrated that social housing condition significantly affects the growth rate of the androgen-responsive Shionogi mouse mammary carcinoma (AR SC115) in male mice. The present study examined the effects of social housing condition and acute daily exposure to a novel environment on the growth rate of an androgen-independent variant of the AR SC115 carcinoma, designated SC115V, in male and female mice. Immediately following tumor cell injection, male and female mice that were reared as individuals (I) or in groups (G) of the same sex were rehoused either from individual to same-sex groups (IG) or from group to individual (GI), or remained in their group housing condition (GG). Approximately half the mice in each housing condition were subjected to acute daily exposure to novel environments (novelty stress), a treatment shown previously to increase the significant difference in tumor growth rates between male mice in the IG and GI housing conditions. The remaining mice were left undisturbed (no novelty stress). In the presence of acute daily novelty stress, the growth rate of the SC115V tumor was significantly increased in GI compared to IG males. However, no significant differences in SC115V tumor growth rates among nonstressed GI, IG, or GG males were observed. For females, in contrast to males, acute daily novelty stress significantly decreased tumor growth in GI compared to IG mice, whereas under nonstressed conditions, tumor growth rate was significantly increased in GI compared to IG females. Neither housing condition nor novelty stress altered estrous cyclicity, nor did the stage of the estrous cycle at the time of tumor cell injection influence tumor growth rates. These findings suggest that social housing condition and novelty stress may interact to produce differential effects on the growth rate of the SC115V tumor in male and female mice.

Effect of gender on postoperative outcomes and hospital stays after coronary artery bypass grafting

BACKGROUND

Compared to men, women undergoing coronary artery bypass grafting appear to have a higher morbidity and mortality, particularly in the perioperative period. This study was designed to answer the questions of whether such differences in clinical outcomes between men and women still exist with improvements in surgical techniques and determine whether it is gender or associated comorbid conditions in women that lead to higher morbidity.

METHODS

An analysis of a single center's contemporary experience (1994 to 1997) of 1,743 consecutive patients undergoing primary coronary artery bypass grafting was performed. Only reoperations were excluded. Data were collected prospectively and presented as mean +/- standard deviation (p<0.05).

RESULTS

Women represented 30.0% of patients. Compared with men, women were older (68.4 versus 63.8 years; p<0.05), and had more urgent surgical interventions (70.0% versus 56.7%; p<0.05), a higher incidence of diabetes (42.1% versus 26.7%; p<0.05), hypertension (82.0% versus 73.9%; p<0.05), lower body surface area (1.73+/-0.18 m2 versus 2.03+/-0.19 m2; p<0.05), and hematocrit (31.7%+/-3.9% versus 36.2%+/-3.9%; p<0.05). Ejection fraction, incidence of previous myocardial infarction, chronic obstructive pulmonary disease, left main (LM) disease, renal insufficiency, extent of coronary disease, and preoperative intraaortic balloon pump were similar. Women received fewer arterial grafts (91.0% versus 95.5%; p<0.05) and distal anastomoses (3.31+/-0.88 versus 3.49+/-0.94 p<0.05). Despite these differences, there were no statistical differences in the incidence of postoperative death (1.5% versus 1.0%), myocardial infarction (0.6% versus 0.6%), or cerebrovascular accident/transient ischemic attack (1.1% versus 0.4%) between men and women. Women had a higher inotropic support (10.2% versus 4.4%; p<0.05) and longer hospital stays (7.3+/-5.7 days versus 6.3+/-4.2 days; p<0.05). Using multivariate analysis, female gender was not an independent predictor of death or postoperative complications but was a predictor of length of hospital stay, use of arterial grafts, and extent of coronary revascularization.

CONCLUSIONS

After accounting for differences in their risk variables, the incidences of death, perioperative myocardial infarction and cerebrovascular accident/ transient ischemic attack after coronary artery bypass grafting in women and men were not statistically significant. Perioperative complications are related to comorbid risk factors but not to female gender itself. Further studies are warranted.

Influence of plate design on cortical bone perfusion and fracture healing in canine segmental tibial fractures

OBJECTIVE

To investigate whether or not the limited contact design of the low-contact dynamic compression plate (LCDCP) provides advantages over the dynamic compression plate (DCP) in the context of cortical bone blood flow, biomechanical properties, and remodeling of bone in segmental tibial fractures.

DESIGN

Randomized trial using canines.

SETTING

Animal research laboratory.

PARTICIPANTS

Eleven canines.

INTERVENTION

Segmental tibial fractures were surgically created in canine tibiae. The tibiae were reduced and stabilized with 316L stainless-steel, 3.5-millimeter, ten-hole plates: LCDCP (n = 5) or DCP (n = 6).

MAIN OUTCOME MEASUREMENTS

Laser Doppler flowmetry evaluated cortical bone perfusion in the proximal tibia, segmental piece, and distal tibia (a) before fracture, (b) after fracture, (c) immediately after plating, and (d) at ten weeks. After the dogs were killed at ten weeks, bending stiffness and load to failure of the tibiae were assessed. Tibial cortical bone porosity and new bone formation were measured.

RESULTS

Cortical bone blood flow was similar between the LCDCP and DCP groups throughout the study. Bending stiffness and load to failure of the tibiae were similar between the two groups. Whereas cortical bone porosity and new bone formation were higher in all plated tibiae at ten weeks compared with controls, no differences in cortical bone porosity were seen between the LCDCP and DCP groups. There was a trend toward significantly more new bone formation in the LCDCP group.

CONCLUSION

The LCDCP is not advantageous in fracture healing or restoration of cortical bone perfusion to devascularized cortex in segmental fractures when plate fixation has been chosen for fracture stabilization. The overall injury following segmental devascularization seems more important to outcome than the type of implant used for fracture fixation up to ten weeks.

Effects of prenatal ethanol exposure on hypothalamic-pituitary-adrenal responses to chronic cold stress in rats

Animals prenatally exposed to ethanol typically exhibit hypothalamic-pituitary-adrenal (HPA) hyperresponsiveness to stressors. In contrast to previous studies that have investigated effects of prenatal ethanol exposure on HPA responses to acute or intermittent stressors, our study investigated HPA responses to a chronic continuous stressor, cold stress (4 degrees C for 0, 1, or 3 days). We tested the hypothesis that prenatal ethanol exposure would result in increased plasma corticosterone (CORT) and adrenocorticotropin (ACTH) responses and increased peptide [corticotropin-releasing factor and vasopressin] mRNA levels in the paraventricular nucleus (PVN) of the hypothalamus compared to that in control animals. In addition, CORT and ACTH responses were measured after exposure to an acute stressor (i.p. isotonic saline injection), superimposed during chronic cold exposure, to examine possible sensitization of the HPA response to the acute stress. Thus, blood samples were collected at the end of each of the three periods of cold exposure, either before (0 min) or 15 min after acute stress. The subjects were adult male and female Sprague-Dawley rat offspring from prenatal ethanol (E), pair-fed (PF), and ad libitum-fed control (C) treatment groups. Exposure to cold stress resulted in significant body weight loss in E males at 1 day and in both males and females of all prenatal treatment groups by 3 days of cold stress. Males in all prenatal groups also exhibited significant increases in adrenal weight:body weight ratios. Cold stress alone (0 min condition) increased CORT levels in E males and overall ACTH levels in E males and females compared to controls. ACTH levels were also higher overall in E compared to control males after acute stress (15 min condition). Sensitization of the CORT response to acute stress was observed in males but not females across all prenatal treatment groups. Corticotropin-releasing factor and vasopressin mRNA levels in the PVN were not significantly affected by prenatal treatment or chronic cold stress in either males or females. In contrast, both males and females displayed increases in PVN thyrotropin-releasing hormone (TRH) mRNA levels after cold stress. These data support and extend previous work demonstrating differential effects of prenatal ethanol exposure on HPA responsiveness of male and female offspring, and suggest that E males may be more vulnerable to the effects of chronic cold stress than E females.

Differential effects of harassment on cardiovascular and salivary cortisol stress reactivity and recovery in women and men

To explore the differential effects of harassment on cardiovascular and neuroendocrine stress reactivity and recovery, 28 men and 32 women were randomized to a harassment or no-harassment control condition (four groups in total). The harassment consisted of three scripted statements delivered during performance of a mental arithmetic stress task. The harassing statements were delivered on a fixed schedule during the task by a same-gender experimenter. Cardiovascular, salivary cortisol, and state affect measures were taken at baseline, immediately posttask, and throughout an extended recovery period. In comparison to the control condition, harassment accentuated the stress reactivity responses on all measures, physiological and self-report of subjective affect. In addition, several gender differences in response to the stressor and during the recovery period were observed. Harassed men had the largest reactivity on cortisol and diastolic blood pressure, whereas the harassed women showed a more pronounced response on heart rate and self-reported hostility. The harassed groups were the only ones to show significant cortisol responses. Within the harassed condition, comparison of effect sizes revealed that cortisol reactivity in men was twice that of women. Control groups did not exhibit significant cortisol changes. During the recovery period, harassed men exhibited attenuated return to baseline on cardiovascular indices and cortisol, whereas women, overall, tended to exhibit an overcompensation response on cardiovascular measures. These results contribute to showing a pathway that may link negative affect (i.e., hostile or angry feelings) with the development of cardiovascular disease.