Exploring the role of primary fibroblast cells in comparative physiology: a historical and contemporary overview.

With the advent of tissue culture, and eventually the in vitro growth and maintenance of individual cell types, it became possible to ask mechanistic questions about whole organism physiology that are impractical to address within a captive setting or within the whole organism. The earliest studies focused on understanding the wound-healing response while refining cell growth and maintenance protocols from various species. In addition to its extensive use in biomedical research, this approach has been co-opted by comparative physiologists interested in reductionist/mechanistic questions related to how cellular physiology can help explain whole organism function. Here, we provide a historical perspective on the emergence of primary cell culture with an emphasis on fibroblasts followed by an overview of applying this method to ask questions about the role of life-history evolution in shaping organismal physiology at the cellular level, as well as the effect of exogenous factors (i.e., temperature, and oxygen availability) on cellular function. Finally, we propose future uses for primary fibroblasts to address questions in conservation biology and comparative physiology.

Testosterone, cortisol, and criminal behavior in men and women.

Only two studies to date have considered the joint effects of testosterone and cortisol on direct measures of criminal behavior. The current study extends this earlier work by incorporating the direct and interactive effects of baseline hormone measures and hormone change scores in response to social stress. The current study also extends prior work by considering distinct measures of different criminal behavior types and sex differences. Analyses based on a large sample of undergraduates indicated that testosterone had a positive and statistically significant association with impulsive and violent criminal behavior. The interaction of testosterone with cortisol had a negative association with income generating crime. Simple slopes analyses of this interaction indicated testosterone had a positive association with income generating crime when cortisol was low (-1 SD). Associations between hormones and criminal behavior were not moderated by sex.

Uplifts, Respite, Stress, and Marital Quality for Parents Raising Children With Down Syndrome or Autism.

Direct, indirect, and partner effects estimated among uplifts, respite care, stress, and marital quality across mothers and fathers of children with autism spectrum disorder (n = 102) and Down syndrome (n = 111) were examined in this cross-sectional study. Parents of children with ASD who reported more uplifts and less stress individually reported better marital quality; these wives reported better marital quality as their husbands reported more uplifts and less stress. Wives with children with DS who reported more uplifts, individually along with their husbands reported less stress and better marital quality. Respite was directly associated with marital quality for parents of children with ASD and indirectly associated with marital quality for parents of children with DS with reduced individual stress. Implications are discussed.

New Perspectives on Avian Models for Studies of Basic Aging Processes.

Avian models have the potential to elucidate basic cellular and molecular mechanisms underlying the slow aging rates and exceptional longevity typical of this group of vertebrates. To date, most studies of avian aging have focused on relatively few of the phenomena now thought to be intrinsic to the aging process, but primarily on responses to oxidative stress and telomere dynamics. But a variety of whole-animal and cell-based approaches to avian aging and stress resistance have been developed-especially the use of primary cell lines and isolated erythrocytes-which permit other processes to be investigated. In this review, we highlight newer studies using these approaches. We also discuss recent research on age-related changes in neural function in birds in the context of sensory changes relevant to homing and navigation, as well as the maintenance of song. More recently, with the advent of "-omic" methodologies, including whole-genome studies, new approaches have gained momentum for investigating the mechanistic basis of aging in birds. Overall, current research suggests that birds exhibit an enhanced resistance to the detrimental effects of oxidative damage and maintain higher than expected levels of cellular function as they age. There is also evidence that genetic signatures associated with cellular defenses, as well as metabolic and immune function, are enhanced in birds but data are still lacking relative to that available from more conventional model organisms. We are optimistic that continued development of avian models in geroscience, especially under controlled laboratory conditions, will provide novel insights into the exceptional longevity of this animal taxon.

Internet and Video Game Addictions: Diagnosis, Epidemiology, and Neurobiology.

In the past 2 decades, there has been substantial increase in availability and use of digital technologies, including the Internet, computer games, smart phones, and social media. Behavioral addiction to use of technologies spawned a body of related research. The recent inclusion of Internet gaming disorder as a condition for further study in the DSM-V invigorated a new wave of researchers, thereby expanding our understanding of these conditions. This article reviews current research, theory, and practice regarding the diagnosis, epidemiology, and neurobiology of Internet and video game addictions.

Respite Care, Stress, Uplifts, and Marital Quality in Parents of Children with Down Syndrome.

Parents of children with disabilities are at risk for high stress and low marital quality; therefore, this study surveyed couples (n = 112) of children with Down syndrome (n = 120), assessing whether respite hours, stress, and uplifts were related to marital quality. Structural equation modeling indicated that respite hours were negatively related to wife/husband stress, which was in turn negatively related to wife/husband marital quality. Also, wife uplifts were positively related to both wife and husband marital quality. Husband uplifts were positively related to husband marital quality. Therefore, it is important that respite care is provided and accessible to parents of children with Down syndrome.

Nutritional limitation in early postnatal life and its effect on aging and longevity in rodents.

Nutrient limitation in the form of chronic dietary restriction (DR), or more specifically a life-long reduction of total daily nutritional intake, was first shown to extend longevity in rats more than eight decades ago and is one of the most robust anti-aging interventions known. More recently, it has become apparent that dietary restriction limited to only the first few weeks of life in rodents is also capable of significantly impacting aging and longevity. The imposition of nutrient limitation is often achieved via the manipulation of litter size or the modulation of maternal nutrient intake during the lactational period. Not surprisingly, nutrient limited pups are smaller at weaning, and remain so throughout their life, while exhibiting signs of slowed aging. In this review, we discuss potential mechanisms that account for the anti-aging effects of postnatal undernutrition with an emphasis on those pathways that parallel changes seen with chronic DR.

Respite Care for Single Mothers of Children with Autism Spectrum Disorders.

Single mothers of children with autism spectrum disorders are rarely studied, yet they may experience unique stressors. Researchers asked 122 single mothers to complete questionnaires concerning respite care, daily hassles/uplifts, depression, and caregiver burden. More than half (59.8%) accessed respite care, which was provided for 1 h per day, often by multiple sources (41%), such as grandparents and community agencies; most were satisfied with this care. Most mothers (77%) were at risk for clinical depression. While uplifts were negatively correlated with depression, hassles and caregiver burden were positively correlated with depression. Respite care was positively related to daily uplifts, and uplifts mediated the relationship between respite care and depression. Recommendations for researchers, policymakers, and school personnel are offered.

Comparative cellular biogerontology: Where do we stand?

Due to the extreme variation in life spans among species, using a comparative approach to address fundamental questions about the aging process has much to offer. For example, maximum life span can vary by as much as several orders of magnitude among taxa. In recent years, using primary cell lines cultured from species with disparate life spans and aging rates has gained considerable momentum as a means to dissect the mechanisms underlying the variation in aging rates among animals. In this review, we reiterate the strengths of comparative cellular biogerontology, as well as provide a survey of the current state of the field. By and large this work sprang from early studies using cell lines derived from long-lived mutant mice. Specifically, they suggested that an enhanced resistance to cellular stress was strongly associated with increased longevity of select laboratory models. Since then, we and others have shown that the degree of stress resistance and species longevity is also correlated among cell lines derived from free-living populations of both mammals and birds, and more recent studies have begun to reveal the biochemical and physiological underpinnings to these differences. The continued study of cultured cell lines from vertebrates with disparate life spans is likely to provide considerable insight toward unifying mechanisms of longevity assurance.

Physiological indicators of pathologic video game use in adolescence.

PURPOSE: Pathologic video game use (PVGU) has been associated with a host of negative psychological, physical, and social outcomes during adolescence; however, little research has examined physiological predictors of such use. The purpose of the study was to examine physiological predictors of the development of PVGU across adolescence. METHODS: The article involves a 1-year longitudinal study across midadolescence. Participants were 374 adolescents and their parents from a large metropolitan area in the Northwest United States. PVGU was assessed via questionnaire, as were a number of control variables. A number of physiological indicators including respiratory sinus arrhythmia (RSA) and galvanic skin conductance (indices of parasympathetic and sympathetic nervous system activity, respectively) were measured during baseline, a cognitively stimulating task (Rubik's cube), and a family problem-solving task. RESULTS: Less RSA withdrawal to a cognitively simulating task was related to greater pathologic video game symptoms, but less RSA withdrawal to a family problem-solving task was associated with the presence of pathologic video game symptoms (p < .05). For girls only, galvanic skin conductance activation during the family problem solving was related to greater pathologic video game symptoms (p < .01). CONCLUSIONS: These findings suggest that adolescents who do not find cognitive tasks stimulating physiologically have a greater severity of PVGU. Additionally, adolescents who show physiological signs of stress in a family task were more likely to have PVGU symptoms and only girls have more severe PVGU levels. This study is the first to show that physiological indicators predict PVGU over time in adolescence and has important implications regarding the prevention and treatment of PVGU in adolescence.

A Longitudinal View of the Association Between Therapist Warmth and Couples' In-Session Process: An Observational Pilot Study of Emotionally Focused Couples Therapy.

This longitudinal dyadic clinical process study used coded data from eleven couples to determine the influence of therapist warmth behaviors on couples' warmth behaviors over time in therapy. A mixed effects model was used to examine within- and between-individual variability. Men and women were modeled separately. A series of two-level multilevel models of change were examined, where Time is Level 1 and Individual is Level 2. Findings were mixed. There was no significant relationship between therapist warmth toward wife and wife warmth toward husband; however, there was a significant relationship between therapist warmth toward husband and husband warmth toward wife. Findings demonstrated that 62.9% of the variance in husband warmth toward wife was accounted for by therapist warmth to husband across time in therapy. Specifically, therapist warmth toward husband was significantly and positively related to husband warmth toward wife over time in therapy. Clinical implications and directions for future research are discussed.

Father involvement: Identifying and predicting family members' shared and unique perceptions.

Father involvement research has typically not recognized that reports of involvement contain at least two components: 1 reflecting a view of father involvement that is broadly recognized in the family, and another reflecting each reporter's unique perceptions. Using a longitudinal sample of 302 families, this study provides a first examination of shared and unique views of father involvement (engagement and warmth) from the perspectives of fathers, children, and mothers. This study also identifies influences on these shared and unique perspectives. Father involvement reports were obtained when the child was 12 and 14 years old. Mother reports overlapped more with the shared view than father or child reports. This suggests the mother's view may be more in line with broadly recognized father involvement. Regarding antecedents, for fathers' unique view, a compensatory model partially explains results; that is, negative aspects of family life were positively associated with fathers' unique view. Children's unique view of engagement may partially reflect a sentiment override with father antisocial behaviors being predictive. Mothers' unique view of engagement was predicted by father and mother work hours and her unique view of warmth was predicted by depression and maternal gatekeeping. Taken, together finding suggests a far more nuanced view of father involvement should be considered.

Linkages between mitochondrial lipids and life history in temperate and tropical birds.

Temperate birds tend to have a fast pace of life and short life spans with high reproductive output, whereas tropical birds tend to have a slower pace of life, invest fewer resources in reproduction, and have higher adult survival rates. How these differences in life history at the organismal level are rooted in differences at the cellular level is a major focus of current research. Here, we cultured fibroblasts from phylogenetically paired tropical and temperate species, isolated mitochondria from each, and compared their mitochondrial membrane lipids. We also correlated the amounts of these lipids with an important life history parameter, clutch size. We found that tropical birds tended to have less mitochondrial lipid per cell, especially less cardiolipin per cell, suggesting that cells from tropical birds have fewer mitochondria or less inner mitochondrial membrane per cell. We also found that the mitochondria of tropical birds and the species with the smallest clutch sizes had higher amounts of plasmalogens, a lipid that could serve as an antioxidant. Overall, our findings are consistent with the idea that there are underlying molecular and cellular physiological traits that could account for the differences in whole-animal physiology between animals with different life histories.

The effect of culling on health and physiology of mouse litters.

Large mouse litters are often culled based on the premise of better survival and growth for the remaining pups. To test whether the culling of litters does provide the benefits of improved survival and growth, mortality and growth were measured in 468 litters of C57BL/6J × 129S1/SvImJ F1 hybrid mice that were unculled or culled to four or six pups per litter. In addition, a limited number of weanlings were evaluated until three months of age for growth, health and physiological measurements. Most measurements did not differ among the cull groups. These included mortality, organ weights (adrenals, kidneys and testes), bone mineral density, percent fat, 12 of the 17 blood parameters, and three of the seven electrocardiographic (EKG) parameters. Several parameters, including five of the 17 blood parameters and four of the seven EKG parameters, showed statistical differences, but all values were physiologically normal. Unculled weanlings showed a reduced weight of 4%, but this weight difference disappeared by three months. These results suggest that mice in culled litters do not demonstrate improved health compared with those in unculled litters.

Older couples with and without cardiovascular disease: testing associations between and among affective communication, marital satisfaction, physical and mental health.

The American Heart Association (Go et al., 2013) estimated that about 2,150 Americans die each day from cardiovascular disease (CVD). For those 65 years of age or older, the total cost of heart related services in 2009 was $121.2 billion (Go et al., 2013). Many people live with the chronic conditions of cardiovascular disease (Petersen et al., 2005). Researchers have identified the genetic, medical, and lifestyle habits of those with CVD, yet there is a dearth of literature focusing on the relational/social aspects of cardiovascular disease and how such factors are associated with the risk, presentation, and maintenance of cardiovascular illness. Considering that men have a higher lifetime risk for developing CVD than women (51.7% to 39.2%; Roger et al., 2012), the purpose of this study was to compare various aspects of the couple relationship among and between couples with a husband who reports CVD and couples in which neither report CVD.

Provenance and geographic spread of St. Louis encephalitis virus.

St. Louis encephalitis virus (SLEV) is the prototypic mosquito-borne flavivirus in the Americas. Birds are its primary vertebrate hosts, but amplification in certain mammals has also been suggested. The place and time of SLEV emergence remain unknown. In an ecological investigation in a tropical rainforest in Palenque National Park, Mexico, we discovered an ancestral variant of SLEV in Culex nigripalpus mosquitoes. Those SLEV-Palenque strains form a highly distinct phylogenetic clade within the SLEV species. Cell culture studies of SLEV-Palenque versus epidemic SLEV (MSI-7) revealed no growth differences in insect cells but a clear inability of SLEV-Palenque to replicate in cells from birds, cotton rats, and free-tailed bats permissive for MSI-7 replication. Only cells from nonhuman primates and neotropical fruit bats were moderately permissive. Phylogeographic reconstruction identified the common ancestor of all epidemic SLEV strains to have existed in an area between southern Mexico and Panama ca. 330 years ago. Expansion of the epidemic lineage occurred in two waves, the first representing emergence near the area of origin and the second involving almost parallel appearances of the virus in the lower Mississippi and Amazon delta regions. Early diversification events overlapped human habitat invasion during the post-Columbian era. Several documented SLEV outbreaks, such as the 1964 Houston epidemic or the 1990 Tampa epidemic, were predated by the arrival of novel strains between 1 and 4 years before the outbreaks. Collectively, our data provide insight into the putative origins of SLEV, suggesting that virus emergence was driven by human invasion of primary rainforests. IMPORTANCE St. Louis encephalitis virus (SLEV) is the prototypic mosquito-transmitted flavivirus of the Americas. Unlike the West Nile virus, which we know was recently introduced into North America from the Old World, the provenience of SLEV is obscure. In an ecological investigation in a primary rainforest area of Palenque National Park, Mexico, we have discovered an ancestral variant of SLEV. The ancestral virus was much less active than the epidemic virus in cell cultures, reflecting its incomplete adaptation to hosts encountered outside primary rainforests. Knowledge of this virus enabled a spatiotemporal reconstruction of the common ancestor of all SLEVs and how the virus spread from there. We can infer that the cosmopolitan SLEV lineage emerged from Central America in the 17th century, a period of post-Columbian colonial history marked by intense human invasion of primary rainforests. Further spread followed major bird migration pathways over North and South America.

Linkages between the life-history evolution of tropical and temperate birds and the resistance of cultured skin fibroblasts to oxidative and non-oxidative chemical injury.

A fundamental challenge facing physiological ecologists is to understand how variation in life history at the whole-organism level might be linked to cellular function. Thus, because tropical birds have higher annual survival and lower rates of metabolism, we hypothesized that cells from tropical species would have greater cellular resistance to chemical injury than cells from temperate species. We cultured dermal fibroblasts from 26 tropical and 26 temperate species of birds and examined cellular resistance to cadmium, H(2)O(2), paraquat, thapsigargin, tunicamycium, methane methylsulfonate (MMS) and UV light. Using ANCOVA, we found that the values for the dose that killed 50% of cells (LD(50)) from tropical birds were significantly higher for H(2)O(2) and MMS. When we tested for significance using a generalized least squares approach accounting for phylogenetic relationships among species to model LD(50), we found that cells from tropical birds had greater tolerance for Cd, H(2)O(2), paraquat, tunicamycin and MMS than cells from temperate birds. In contrast, tropical birds showed either lower or no difference in tolerance to thapsigargin and UV light in comparison with temperate birds. These findings are consistent with the idea that natural selection has uniquely fashioned cells of long-lived tropical bird species to be more resistant to forms of oxidative and non-oxidative stress than cells from shorter-lived temperate species.

Walking the walk: the moderating role of proactive parenting on adolescents' value-congruent behaviors.

The current study longitudinally examined adolescents' internalization of values in four domains (drug use, prosocial, school, friends), and how these values were differentially related to behaviors (delinquency, prosocial behavior, school engagement, and deviant peer association) as a function of proactive parenting. Participants included 335 adolescents (M age of child at Time 2 = 12.28, SD = .99, 51% female) and their parents. Analyses examined associations between adolescents' values at Time 3 and corresponding behaviors at Time 4, and the moderating role of proactive parenting (assessed at Time 2 using cluster analysis). Results suggested that adolescents with the most consistent value-congruent behavior had parents who used deference or reasoned deference as an approach to proactive parenting, highlighting the importance of autonomy supportive parenting in the encouragement of self-generated values and corresponding behaviors. Discussion focused on value-congruent behaviors and associations between values and behaviors across domains.