Biological Research For Nursing

The theoretical constructs of allostasis and allostatic load (AL) have contributed to our understanding of how constantly changing social and environmental factors impact physiological functioning and shape health and aging disparities, particularly along socioeconomic, gendered, racial, and ethnic lines. AL represents the cumulative dysregulation of biological systems with prolonged or poorly regulated allostatic responses. Nearly two decades of empirical research has focused on operationalizing the AL construct for examining the antecedents and health outcomes accompanying multisystem biological dysregulation. The purpose of this systematic review is to examine the empirical literature that quantifies the AL construct; the review also evaluates the social, environmental, and genetic antecedents of AL as well as its predictive utility for a variety of health outcomes. A total of 58 articles published between 1997 and 2012 were retrieved, analyzed, and synthesized. The results revealed considerable heterogeneity in the operationalization of AL and the measurement of AL biomarkers, making interpretations and comparisons across studies challenging. There is, however, empirical substantiation for the relationships between AL and socioeconomic status, social relationships, workplace, lifestyle, race/ethnicity, gender, stress exposure, and genetic factors. The literature also demonstrated associations between AL and physical and mental health and all-cause mortality. Targeting the antecedents of AL during key developmental periods is essential for improving public health. Priorities for future research include conducting prospective longitudinal studies, examining a broad range of antecedent allostatic challenges, and collecting reliable measures of multisystem dysregulation explicitly designed to assess AL, at multiple time points, in population-representative samples.

Analytes and biomarkers present in saliva may provide insight into individual differences in environmental chemical exposures, variation in reproductive hormones, therapeutic and illegal substance use, changes in stress-related physiology, and the immunologic footprints of infectious disease. The wealth of information provided by salivary analytes has the potential to enrich biobehavioral nursing research by enabling researchers to measure these individual differences in the clinic as well as in patients’ and participants’ everyday social worlds. In this article, the authors provide a roadmap for researchers new to this area who would like to learn more about integrating salivary biospecimens into the next generation of health research. In addition, the authors highlight best practices and strategies to avoid common pitfalls for researchers already engaged in this field.

Interval exercise has been used as an alternative modality to continuous exercise in patients with various conditions. Although interval exercise can improve health status, it may also exert deleterious effects. Few data are available on differences in psychoneuroimmunological response to high-intensity interval exercise, and it is not known whether males and females differ in their responses to a similar physical stress task. The aim of this study was to evaluate the differences between the psychoneuroimmunological responses of healthy active males and females to a high-intensity interval exercise protocol. Fifty healthy active subjects (25 females) underwent 2 exercise protocol sessions at least 2 weeks apart and at the same time of the day. The first session familiarized participants with the protocol. In the second, after a baseline measurement, subjects performed an exercise protocol with a standardized warm-up followed by three 30-s Wingate tests and an active recovery period. Baseline and postintervention data were gathered on the following: Holter electrocardiogram recordings (standard deviation of normal-to-normal interval [SDNN], square root of mean squared differences of successive NN intervals [RMSSD]); heart rate variability (HRV) index; salivary total protein and immunoglobulin A levels; pressure pain thresholds in masseter and upper trapezius muscles; and profile of mood states. After the exercise protocol, mood disturbance was significantly greater in the males than in the females, while the salivary immunoglobulin A level relative to total proteins was significantly lower in the males. These results suggest that high-intensity interval exercise induces a worse psychoneuroimmunological state in males than in females.

The prevalence of obesity and obesity-related illnesses is higher among Hispanics (Latinos) than other racial and ethnic groups, and rates increase exponentially with the number of years living in the United States. Mounting evidence suggests that the origins of many chronic illnesses among disadvantaged minority groups may lie with cumulative exposure to chronic psychological and physiological stressors through the biobehavioral process of allostatic load (AL). Among immigrant Latinos, acculturation stress may contribute to an increase in AL and thus may be an independent risk factor for the development of obesity and obesogenic illnesses. The purpose of this theoretical article is to present a proposed model of the effects of acculturation stress on AL and obesity among Latino immigrants. Such a model can be useful to guide intervention efforts to decrease obesity among immigrant Latinos by adding education, skill building, and social integration strategies to healthy eating and physical activity to reduce the deleterious impact of acculturation stress.

Premature infants confront numerous physiologic and environmental stressors in the neonatal intensive care unit (NICU) that have the potential to permanently alter their neurodevelopment. Schore’s regulation theory postulates that positive maternal–infant interactions can shape the infant’s developmental outcomes through inducing mechanistic changes in brain structure and function. The purposes of this article are to explain the regulation of infant neurobiological processes during interactions between mothers and healthy infants in the context of Schore’s theory, to identify threats to these processes for premature infants, and to propose principles of clinical practice and areas of research necessary to establish a supportive environment and prevent or reduce maladaptive consequences for these vulnerable infants. A premature birth results in the disruption of neurodevelopment at a critical time. Chronic exposure to stressors related to the NICU environment overwhelms immature physiologic and stress systems, resulting in significant allostatic load, as measured by long-term neurodevelopmental impairments in the premature infant. Positive maternal–infant interactions during NICU hospitalization and beyond have the potential to reduce neurologic deficits and maximize positive neurodevelopmental outcomes in premature infants. The quality of the maternal–infant interaction is affected not only by the infant’s developing neurobiology but also by the mother’s responses to the stressors surrounding a premature birth and mothering an infant in the NICU environment. Nurses can empower mothers to overcome these stressors, promote sensitive interactions with their infants, and facilitate neurodevelopment. Research is critically needed to develop and test nursing interventions directed at assisting mothers in supporting optimal neurodevelopment for their infants.

Informal caregivers of stroke survivors experience elevated chronic stress and are at risk of developing depressive symptoms. The cumulative effects of chronic stress can increase allostatic load and dysregulate biological processes, thus increasing risk of stress-related disease. Stress-induced alterations in the pattern of cortisol secretion vary with respect to stressor onset, intensity, and chronicity. Little is known about the psychoendocrine response to stress in female caregivers of stroke survivors. The purpose of this study was to examine perceived stress, caregiver burden, and the association between caregiver depressive symptoms and diurnal cortisol in 45 females caring for a significant other who experienced a stroke within the past year. Women completed the Center for Epidemiologic Studies Depression Scale (CES-D) and collected saliva for cortisol upon awakening, 30 min postawakening, noon, and bedtime for 2 consecutive days. Results revealed that women had high levels of perceived stress and caregiver burden. In women with CES-D scores ≥ 16, salivary cortisol levels were significantly lower across the day relative to women with CES-D scores < 16. This difference persisted after adjusting for age, number of caregiving hours per week, perceived social support, and quality of sleep. Younger age was associated with more depressive symptoms as well as lower levels of cortisol at awakening and 30 min postawakening. Results demonstrate that the burden of caregiving increases risk of depressive symptoms and hypocortisolism across the day. Hypocortisolism may contribute to increased risk of depressive symptoms as a result of the loss of glucocorticoid attenuation of stress-induced inflammation.

Low heart rate variability (HRV) can occur with psychological disorders such as posttraumatic stress disorder (PTSD). The purpose of this study was to examine the association between PTSD by trauma type and decreased HRV measures in female veterans with cardiac symptoms. This secondary analysis utilized data from a previous study of female veterans (n = 125) examined for cardiac symptoms by Holter and electrocardiogram recordings at a Veterans Affairs medical center. The mean HRV measure from three 10-s data segments with spontaneous respirations was obtained for each subject. PTSD diagnosis and type of trauma exposure were collected from mental health consult notes. Chi-square was used for frequency of subject characteristics; independent t tests and one-way analysis of variance (ANOVA) compared means of HRV measures between trauma types. Statistical significance was set at p < .05 a priori. By ANOVA, significantly lower log-transformed standard deviation of all normal sinus rhythm R-R intervals (SDNN) and log-transformed square root of the mean of the sum of the squares of differences between adjacent normal sinus rhythm R-R intervals (RMSSD) were found in the PTSD group with documented rape military sexual trauma (MST) compared to other groups including no PTSD, PTSD following MST with rape not specified, combat exposure, and nonmilitary-related trauma; lower HRV measures were not found with other PTSD types of trauma. This study suggests rape MST with concomitant PTSD may be a risk factor for decreased HRV in female veterans examined for cardiac symptoms.

Caring, a core tenet of nursing practice, grew out of a holistic approach. Nurse theorists often note the establishment of a therapeutic relationship as the beginning point of caring, with subsequent nursing interventions reliant upon this relationship for effectiveness. Relational exchange serves as a source of either stress or healing between participants, and rarely is its impact neutral. Relational stress, in fact, has become a primary contributor to many disease processes in terms of promotion and progression and perhaps even initiation. Patient–provider relationships have a long history in medical and nursing literature as critical to providing effective interventions, but our understanding of relational dynamics between patients and providers remains fairly superficial. This theoretical article adapts a previously described biobehavioral model to illustrate the nature and centrality of caring relationships in nursing practice. The dynamic process of face-to-face engagement is deconstructed from a psychobiological standpoint in order to understand the physiological, emotional, cognitive, and behavioral impacts of relational interaction. This understanding is then applied to the patient–provider relationship. Finally, the utility of biomarkers of stress, positive emotion and resonance, and of disease is discussed relative to the patient-provider relationship. Methodological and interpretive challenges inherent in this line of research, along with suggestions to address such challenges, are also presented.