Laura Cousino Klein

Relation of oxytocin to psychological stress responses and hypothalamic-pituitary-adrenocortical axis activity in older women.

Objective: Animal research suggests that oxytocin (OT) plays a role in stress responses and that in females, this role is modulated by estrogen. Yet little is known about the relation of OT to human stress responses. This study was conducted to examine the relations between estrogen activity and OT, identify stressors distinctively associated with elevations in OT, and investigate whether OT is related to cardiovascular and hypothalamic-pituitary-adrenocortical (HPA) activity in a laboratory challenge paradigm. Methods: Seventy-three postmenopausal women who were on hormone therapy (HT) or not completed questionnaires assessing psychological distress and social relationships and then participated in a laboratory stress challenge (Trier Social Stress Task), during which OT, cortisol, and blood pressure were assessed. Results: HT was significantly associated with higher plasma OT. Controlling for HT, elevated plasma OT was significantly associated with gaps in social relationships, with less positive relationships with a primary partner, and with elevated cortisol levels. OT was not associated with stress reactivity or recovery. Conclusion: In women, plasma OT signals relationship stress and is associated with elevated cortisol; it does not appear to significantly affect cortisol or blood pressure responses to acute stress. OT = oxytocin; HPA = hypothalamic-pituitary-adrenocortical; HT = hormone therapy; TSST = Trier Social Stress Test; CAD = coronary artery disease; CHF = coronary heart failure; CRC = UCLA Clinical Research Center; BP = blood pressure; SCL-90 = Brief Symptom Inventory; PANAS = Positive and Negative Affect Schedule; RPM = rotations per minute; HLM = hierarchical linear modeling; GCA = growth curve analysis.

Frontiers in the Use of Biomarkers of Health in Research on Stress and Aging

Assessment of biomarkers that reflect objective indicators of physiological processes has become increasingly popular in psychological research on stress and aging. The current article reviews biomarkers of the neuroendocrine and immune systems, including issues related to measurement and normative age-related changes. We also discuss how exposure to stressors can provoke changes in these biomarkers and propose that stressful experiences may accelerate age-related declines in these systems. We recommend that future research examining physical health and aging incorporate dynamic and multivariate methods for assessing links between stressors and biomarkers.

Appraised control, coping, and stress in a community sample: A test of the goodness-of-fit hypothesis

Lazarus and Folkman proposed one of the most comprehensive theories of stress and coping in the psychology literature, but many of their postulates have received little empirical attention, and some of the existing research has yielded contradictory findings. This longitudinal study sought to clarify the associations among control appraisal, coping, and stress within this theoretical framework. The theory postulates that coping strategies used tend to match the level of appraised controllability of the stressor (matching hypothesis). It further states that the effects of problem-focused versus emotion-focused coping are moderated by the appraised controllability of the stressor (goodness-of-fit hypothesis). An alternative to the latter is the main-effects hypothesis, which states that problem-focused coping is generally more effective in reducing distress regardless of appraisal. These hypotheses were tested on 72 adults who completed questionnaires on coping and control appraisal. Stress was assessed using self-report (Symptom Checklist-90-Revised) and a behavioral measure (proofreading task) at two times approximately 2 months apart. Appraised control significantly predicted type of coping such that greater control was associated with more problem-focused and less emotion-focused coping. Although the main-effects hypothesis was not supported, the goodness-of-fit hypothesis was partly confirmed by a significant control by emotion-focused coping interaction predicting both self-report and behavioral measures of stress.

Effectiveness of the gluten-free, casein-free diet for children diagnosed with autism spectrum disorder: Based on parental report

Abstract Objectives Studies on the gluten-free and/or casein-free (GFCF) dietary intervention for children with autism spectrum disorders (ASDs) suggest that some children may positively respond to implementation of the dietary intervention. Other research suggests that children diagnosed with ASD can be classified into subpopulations based on various factors, including gastrointestinal (GI) abnormalities and immune function. Methods This study analyzes parental report data collected using a 90-item online questionnaire from 387 parents or primary caregivers of children diagnosed with ASD on the efficacy of the GFCF diet. Parents reported on their childs GI symptoms, food allergy diagnoses, and suspected food sensitivities, as well as the degree and length of their diet implementation. Results Overall, diet efficacy among children whose parents reported the presence of GI symptoms, food allergy diagnoses, and suspected food sensitivities included greater improvement in ASD behaviors, physiological symptoms, and social behaviors compared with children whose parents reported none of these symptoms, diagnoses, or sensitivities (P < 0.05). Parental report of strict diet implementation, indicated by complete gluten/casein elimination and infrequent diet errors during and outside of parental care, also corresponded to improvement in ASD behaviors, physiological symptoms, and social behaviors (P < 0.05). Discussion These findings suggest that various intricacies related to diet implementation and GI and immune factors may play a role in differentiating diet responders from diet non-responders and substantiate the importance of further investigations into the various, nuanced factors that influence efficacy of the intervention among children with ASDs.

Sex differences in voluntary oral nicotine consumption by adolescent mice: a dose-response experiment.

Recent studies with adolescent rodents offer valuable information regarding the neurochemical and behavioral effects of adolescent nicotine exposure. One hundred twenty-one male and 125 female adolescent (35 days of age) C57BL/6J mice were tested for voluntary nicotine consumption by providing 24-h access to both saccharin-only (SAC) and one of six nicotine-containing solutions [10, 25, 50, 75, 100, 200 ug (-)-freebase nicotine/ml in 2% SAC] in the home cage for 7 days. Although males and females drank similar volumes (ml) of nicotine, the female mice consumed more nicotine adjusted for body weight (mg/kg) and as a percentage of total fluid intake than did the male mice. In contrast, there was no sex difference in overall serum cotinine levels (adjusted for liver weight). For all mice, nicotine consumption and serum cotinine levels increased in a dose-dependent manner, and the volume of nicotine intake (ml), percent nicotine intake, and nicotine dosage (mg/kg) on the last day of the experiment were positively correlated with cotinine levels. Cotinine levels were inversely related to body weight only for females. Sex differences in nicotine consumption, but not in cotinine levels, suggest sex differences in pharmacokinetic processes that may contribute to oral nicotine consumption behavior during periadolescence.

Effects of Diets High in Walnuts and Flax Oil on Hemodynamic Responses to Stress and Vascular Endothelial Function

Background: Polyunsaturated fatty acids (PUFA) have beneficial effects on cardiovascular risk, although the mechanisms are incompletely understood. In a previous article, we showed significant reductions in low-density lipoprotein cholesterol and several markers of inflammation with increasing intake of alpha-linolenic acid (ALA) from walnuts and flax. Objective: To examine effects of ALA on cardiovascular responses to acute stress, flow-mediated dilation (FMD) of the brachial artery, and blood concentrations of endothelin-1 and arginine-vasopressin (AVP). Design: Using a randomized, crossover study design, cardiovascular responses to acute stress were assessed in 20 hypercholesterolemic subjects, a subset of whom also underwent FMD testing (n  =  12). Participants were fed an average American diet (AAD) and 2 experimental diets that varied in the amount of ALA and linoleic acid (LA) that they contained. The AAD provided 8.7% energy from PUFA (7.7% LA, 0.8% ALA). On the LA diet, saturated fat was reduced, and PUFA from walnuts and walnut oil provided 16.4% of energy (12.6% LA, 3.6% ALA). On the ALA diet, walnuts, walnut oil, and flax oil provided 17% energy from PUFA (10.5% LA, 6.5% ALA). Results: The ALA and LA diets significantly reduced diastolic blood pressure (−2 to −3 mm Hg) and total peripheral resistance (−4%), and this effect was evident at rest and during stress (main effect of diet, p < 0.02). FMD increased (+34%) on the diet containing additional ALA. AVP also increased by 20%, and endothelin-1 was unchanged. Conclusions: These results suggest novel mechanisms for the cardioprotective effects of walnuts and flax, and further work is needed to identify the bioactives responsible for these effects.

Maternal nicotine exposure increases nicotine preference in periadolescent male but not female C57Bl/6J mice

Maternal cigarette smoking is a risk factor for adolescent smoking. One possible explanation for increased smoking by human adolescents after maternal nicotine exposure is that exposure increases nicotine preference. However, it is difficult to separate the biological and social causes of smoking behavior in humans. This experiment examined the relationship between maternal nicotine exposure and nicotine preference in periadolescent offspring using a mouse model of oral nicotine consumption. Pregnant females were provided saccharin-flavored water containing 50 microg/ml nicotine (n = 4) or no nicotine (n = 5) from the ninth day of gestation through weaning on postnatal day (PD) 21. Offspring from these females were tested for nicotine preference during periadolescence (PDs 35-42) by providing access to both saccharin-only and nicotine solutions (50 microg/ml) 24 hr a day in the home cage in a two-bottle choice test. Male mice exposed maternally to nicotine (n = 9) exhibited an increased nicotine preference in adolescence compared to non-nicotine exposed controls (n = 12). Maternal nicotine exposure did not alter nicotine preference by periadolescent female mice. Nicotine consumption was confirmed by serum cotinine measurement. These data are consistent with human epidemiological reports that maternal nicotine exposure is associated with increased risk of cigarette smoking. Differential outcomes for males and females suggest that different processes underlie sex differences in nicotine consumption following maternal nicotine exposure.

Sex differences in effects of predictable and unpredictable footshock on fentanyl self-administration in rats.

An operant conditioning paradigm was used to examine effects of predictable and unpredictable footshock on oral fentanyl (50 micrograms/ml self-administration (SA) in 12 female and 12 male Wistar rats (Rattus norvegicus). Rats were tested for drug SA under a progressive ratio schedule with and without repeated predictable or unpredictable footshock over 8 weeks. Female rats consumed greater amounts of fentanyl than did male rats. Male rats exhibited greater withdrawal behaviors following naloxone challenge. Predictable footshock with repeated exposure (i.e., chronic stress) was accompanied by greater fentanyl SA than was unpredictable footshock, particularly for female rats. Corticosterone levels were positively correlated with fentanyl SA. Predictability of the stressor also had a greater effect on maintenance of fentanyl SA than it did on relapse to fentanyl SA. Results suggest that sex plays an important role in drug-taking behavior by rats.

Synchrony of diurnal cortisol pattern in couples.

Cortisol is a biomarker of stress reactivity, and its diurnal pattern is an indicator of general neuroendocrine health. Despite theories conceptualizing marital dyads as dynamic systems wherein spouses are interdependent in their physiology and stress coping, little is known about the daily processes in which spouses possibly influence each other in biological stress. Nineteen heterosexual couples provided saliva samples containing cortisol 4 times a day for 4 consecutive days. We used multilevel modeling to examine whether ones cortisol awaking response (CAR) and diurnal cortisol slope (DCS) predict those of the spouses on the same day and/or on the next day. We found that spouses synchronize their DCS, such that on days when one experiences faster or slower decline in diurnal cortisol than usual, the spouse also experiences faster or slower decline than usual. For CAR, positive synchrony was only observed in couples reporting high levels of marital strain and disagreement. Cross-lagged regression analysis reveals stability in diurnal cortisol pattern. A steeper cortisol slope on a particular day predicts a steeper slope on the next day within an individual, but no significant cross-lagged relation was found between spouses. Couples reporting more spousal support tend to have stronger stability in CAR. These findings provide evidence that spouses are interdependent in their diurnal cortisol patterns on a day-to-day basis, and that these daily dynamics are associated with marital relationship quality. The study contributes to our understanding of marital processes and biobehavioral health. It also contributes methodologically to the advancement of longitudinal dyadic analysis.

The Landscape in Global Tobacco Control Research: A Guide to Gaining a Foothold

Smoking prevalence is shifting from more- to less-developed countries. In higher-income countries, smoking surveillance data, tailored treatments, public health campaigns, and research-based policy implementation have led to a decrease in tobacco use. In low- and middle-income countries, translating research into practice and policy is integral for tobacco control. We describe the landscape of existing resources, both financial and structural, to support global tobacco control research and strengthen research capacity in developing countries. We identify key organizations that support international efforts, provide examples of partnerships between developed and developing countries, and make recommendations for advancing global tobacco research. There is a need for increased commitment from organizations to support global tobacco control research.