Sex difference in top performers from Ironman to double deca iron ultra-triathlon

PubMed Central

Knechtle, Beat; Zingg, Matthias A; Rosemann, Thomas; Rüst, Christoph A

2014-01-01

This study investigated changes in performance and sex difference in top performers for ultra-triathlon races held between 1978 and 2013 from Ironman (3.8 km swim, 180 km cycle, and 42 km run) to double deca iron ultra-triathlon distance (76 km swim, 3,600 km cycle, and 844 km run). The fastest men ever were faster than the fastest women ever for split and overall race times, with the exception of the swimming split in the quintuple iron ultra-triathlon (19 km swim, 900 km cycle, and 210.1 km run). Correlation analyses showed an increase in sex difference with increasing length of race distance for swimming (r2=0.67, P=0.023), running (r2=0.77, P=0.009), and overall race time (r2=0.77, P=0.0087), but not for cycling (r2=0.26, P=0.23). For the annual top performers, split and overall race times decreased across years nonlinearly in female and male Ironman triathletes. For longer distances, cycling split times decreased linearly in male triple iron ultra-triathletes, and running split times decreased linearly in male double iron ultra-triathletes but increased linearly in female triple and quintuple iron ultra-triathletes. Overall race times increased nonlinearly in female triple and male quintuple iron ultra-triathletes. The sex difference decreased nonlinearly in swimming, running, and overall race time in Ironman triathletes but increased linearly in cycling and running and nonlinearly in overall race time in triple iron ultra-triathletes. These findings suggest that women reduced the sex difference nonlinearly in shorter ultra-triathlon distances (ie, Ironman), but for longer distances than the Ironman, the sex difference increased or remained unchanged across years. It seems very unlikely that female top performers will ever outrun male top performers in ultratriathlons. The nonlinear change in speed and sex difference in Ironman triathlon suggests that female and male Ironman triathletes have reached their limits in performance. PMID:25114605

The neural correlates of sex differences in emotional reactivity and emotion regulation.

PubMed

Domes, Gregor; Schulze, Lars; Böttger, Moritz; Grossmann, Annette; Hauenstein, Karlheinz; Wirtz, Petra H; Heinrichs, Markus; Herpertz, Sabine C

2010-05-01

Sex differences in emotional responding have been repeatedly postulated but less consistently shown in empirical studies. Because emotional reactions are modulated by cognitive appraisal, sex differences in emotional responding might depend on differences in emotion regulation. In this study, we investigated sex differences in emotional reactivity and emotion regulation using a delayed cognitive reappraisal paradigm and measured whole-brain BOLD signal in 17 men and 16 women. During fMRI, participants were instructed to increase, decrease, or maintain their emotional reactions evoked by negative pictures in terms of cognitive reappraisal. We analyzed BOLD responses to aversive compared to neutral pictures in the initial viewing phase and the effect of cognitive reappraisal in the subsequent regulation phase. Women showed enhanced amygdala responding to aversive stimuli in the initial viewing phase, together with increased activity in small clusters within the prefrontal cortex and the temporal cortex. During cognitively decreasing emotional reactions, women recruited parts of the orbitofrontal cortex, the anterior cingulate, and the dorsolateral prefrontal cortex to a lesser extent than men, while there was no sex effect on amygdala activity. In contrast, compared to women, men showed an increased recruitment of regulatory cortical areas during cognitively increasing initial emotional reactions, which was associated with an increase in amygdala activity. Clinical implications of these findings are discussed.

Sex differences in the neural substrates of spatial working memory during adolescence are not mediated by endogenous testosterone.

PubMed

Alarcón, Gabriela; Cservenka, Anita; Fair, Damien A; Nagel, Bonnie J

2014-12-17

Adolescence is a developmental period characterized by notable changes in behavior, physical attributes, and an increase in endogenous sex steroid hormones, which may impact cognitive functioning. Moreover, sex differences in brain structure are present, leading to differences in neural function and cognition. Here, we examine sex differences in performance and blood oxygen level-dependent (BOLD) activation in a sample of adolescents during a spatial working memory (SWM) task. We also examine whether endogenous testosterone levels mediate differential brain activity between the sexes. Adolescents between ages 10 and 16 years completed a SWM functional magnetic resonance imaging (fMRI) task, and serum hormone levels were assessed within seven days of scanning. While there were no sex differences in task performance (accuracy and reaction time), differences in BOLD response between girls and boys emerged, with girls deactivating brain regions in the default mode network and boys showing increased response in SWM-related brain regions of the frontal cortex. These results suggest that adolescent boys and girls adopted distinct neural strategies, while maintaining spatial cognitive strategies that facilitated comparable cognitive performance of a SWM task. A nonparametric bootstrapping procedure revealed that testosterone did not mediate sex-specific brain activity, suggesting that sex differences in BOLD activation during SWM may be better explained by other factors, such as early organizational effects of sex steroids or environmental influences. Elucidating sex differences in neural function and the influence of gonadal hormones can serve as a basis of comparison for understanding sexually dimorphic neurodevelopment and inform sex-specific psychopathology that emerges in adolescence. Copyright © 2014 Elsevier B.V. All rights reserved.

An Association Mapping Framework To Account for Potential Sex Difference in Genetic Architectures.

PubMed

Kang, Eun Yong; Lee, Cue Hyunkyu; Furlotte, Nicholas A; Joo, Jong Wha J; Kostem, Emrah; Zaitlen, Noah; Eskin, Eleazar; Han, Buhm

2018-05-11

Over the past few years, genome-wide association studies have identified many trait-associated loci that have different effects on females and males, which increased attention to the genetic architecture differences between the sexes. The between-sex differences in genetic architectures can cause a variety of phenomena such as differences in the effect sizes at trait-associated loci, differences in the magnitudes of polygenic background effects, and differences in the phenotypic variances. However, current association testing approaches for dealing with sex, such as including sex as a covariate, cannot fully account for these phenomena and can be suboptimal in statistical power. We present a novel association mapping framework, MetaSex, that can comprehensively account for the genetic architecture differences between the sexes. Through simulations and applications to real data, we show that our framework has superior performance than previous approaches in association mapping. Copyright © 2018, Genetics.

Sex and the development of Alzheimer’s disease

PubMed Central

Pike, Christian J.

2016-01-01

Men and women exhibit differences in the development and progression of Alzheimer’s disease (AD). The factors underlying the sex differences in AD are not well understood. This review emphasizes the contributions of sex steroid hormones to the relationship between sex and AD. In women, events that decrease lifetime exposure to estrogens are generally associated with increased AD risk, whereas estrogen-based hormone therapy administered near the time of menopause may reduce AD risk. In men, estrogens do not exhibit age-related reduction and are not significantly associated with AD risk. Rather, normal age-related depletions of testosterone in plasma and brain predict enhanced vulnerability to AD. Both estrogens and androgens exert numerous protective actions in the adult brain that increase neural functioning and resilience as well as specifically attenuate multiple aspects of AD-related neuropathology. Aging diminishes the activational effects of sex hormones in sex-specific manners, which is hypothesized to contribute to the relationship between aging and AD. Sex steroid hormones may also drive sex differences in AD through their organizational effects during developmental sexual differentiation of the brain. Specifically, sex hormone actions during early development may confer inherent vulnerability of the female brain to development of AD in advanced age. The combined effects of organizational and activational effects of sex steroids yield distinct sex differences in AD pathogenesis, a significant variable that must be more rigorously considered in future research. PMID:27870425

Coevolution of parental investment and sexually selected traits drives sex-role divergence.

PubMed

Fromhage, Lutz; Jennions, Michael D

2016-08-18

Sex-role evolution theory attempts to explain the origin and direction of male-female differences. A fundamental question is why anisogamy, the difference in gamete size that defines the sexes, has repeatedly led to large differences in subsequent parental care. Here we construct models to confirm predictions that individuals benefit less from caring when they face stronger sexual selection and/or lower certainty of parentage. However, we overturn the widely cited claim that a negative feedback between the operational sex ratio and the opportunity cost of care selects for egalitarian sex roles. We further argue that our model does not predict any effect of the adult sex ratio (ASR) that is independent of the source of ASR variation. Finally, to increase realism and unify earlier models, we allow for coevolution between parental investment and investment in sexually selected traits. Our model confirms that small initial differences in parental investment tend to increase due to positive evolutionary feedback, formally supporting long-standing, but unsubstantiated, verbal arguments.

Coevolution of parental investment and sexually selected traits drives sex-role divergence

PubMed Central

Fromhage, Lutz; Jennions, Michael D.

2016-01-01

Sex-role evolution theory attempts to explain the origin and direction of male–female differences. A fundamental question is why anisogamy, the difference in gamete size that defines the sexes, has repeatedly led to large differences in subsequent parental care. Here we construct models to confirm predictions that individuals benefit less from caring when they face stronger sexual selection and/or lower certainty of parentage. However, we overturn the widely cited claim that a negative feedback between the operational sex ratio and the opportunity cost of care selects for egalitarian sex roles. We further argue that our model does not predict any effect of the adult sex ratio (ASR) that is independent of the source of ASR variation. Finally, to increase realism and unify earlier models, we allow for coevolution between parental investment and investment in sexually selected traits. Our model confirms that small initial differences in parental investment tend to increase due to positive evolutionary feedback, formally supporting long-standing, but unsubstantiated, verbal arguments. PMID:27535478

Increased fat deposition in injured skeletal muscle is regulated by sex-specific hormones

PubMed Central

McHale, Matthew J.; Sarwar, Zaheer U.; Cardenas, Damon P.; Porter, Laurel; Salinas, Anna S.; Michalek, Joel E.; McManus, Linda M.

2012-01-01

Sex differences in skeletal muscle regeneration are controversial; comparisons of regenerative events between sexes have not been rigorously defined in severe injury models. We comprehensively quantified inflammation and muscle regeneration between sexes and manipulated sex-specific hormones to determine effects on regeneration. Cardiotoxin injury was induced in intact, castrated and ovariectomized female and male mice; ovariectomized mice were replaced with low- or high-dose 17-β estradiol (E2) or progesterone (P4). Extent of injury was comparable between intact mice, but females were more efficient in removal of necrotic debris, despite similar tissue levels of inflammatory cells and chemokines. Myofiber size during regeneration was equivalent between intact mice and after castration or ovariectomy (OVX) but was decreased (P < 0.001) in ovariectomized mice with high-dose E2 replacement. Intermuscular adipocytes were absent in uninjured muscle, whereas adipocyte area was increased among regenerated myofibers in all groups. Interestingly, intermuscular fat was greater (P = 0.03) in intact females at day 14 compared with intact males. Furthermore, castration increased (P = 0.01) and OVX decreased adipocyte accumulation. After OVX, E2, but not P4, replacement decreased (P ≤ 0.03) fat accumulation. In conclusion, sex-dependent differences in regeneration consisted of more efficient removal of necrosis and increased fat deposition in females with similar injury, inflammation, and regenerated myofiber size; high-dose E2 decreased myofiber size and fat deposition. Adipocyte accumulation in regenerating muscle was influenced by sex-specific hormones. Recovery following muscle injury was different between males and females, and sex-specific hormones contributed to these differences, suggesting that sex-specific treatments could be beneficial after injury. PMID:22116509

Analysis of sex and gender-specific research reveals a common increase in publications and marked differences between disciplines

PubMed Central

2010-01-01

Background The incorporation of sex and gender-specific analysis in medical research is increasing due to pressure from public agencies, funding bodies, and the clinical and research community. However, generations of knowledge and publication trends in this discipline are currently spread over distinct specialties and are difficult to analyze comparatively. Methods Using a text-mining approach, we have analysed sex and gender aspects in research within nine clinical subspecialties - Cardiology, Pulmonology, Nephrology, Endocrinology, Gastroenterology, Haematology, Oncology, Rheumatology, Neurology - using six paradigmatic diseases in each one. Articles have been classified into five pre-determined research categories - Epidemiology, Pathophysiology, Clinical research, Management and Outcomes. Additional information has been collected on the type of study (human/animal) and the number of subjects included. Of the 8,836 articles initially retrieved, 3,466 (39%) included sex and gender-specific research and have been further analysed. Results Literature incorporating sex/gender analysis increased over time and displays a stronger trend if compared to overall publication increase. All disciplines, but cardiology (22%), demonstrated an underrepresentation of research about gender differences in management, which ranges from 3 to 14%. While the use of animal models for identification of sex differences in basic research varies greatly among disciplines, studies involving human subjects are frequently conducted in large cohorts with more than 1,000 patients (24% of all human studies). Conclusions Heterogeneity characterizes sex and gender-specific research. Although large cohorts are often analysed, sex and gender differences in clinical management are insufficiently investigated leading to potential inequalities in health provision and outcomes. PMID:21067576

Asthma, the sex difference.

PubMed

Kynyk, Jessica A; Mastronarde, John G; McCallister, Jennifer W

2011-01-01

asthma is a common chronic disease with significant clinical impact worldwide. Sex-related disparities in asthma epidemiology and morbidity exist but debate continues regarding the mechanisms for these differences. There is a need to review the recent findings for asthma care providers and to highlight areas in need of additional research. recent data illustrate striking sex-related differences in asthma epidemiology and disease expression. Studies show an increased incidence of asthma in women. Data demonstrate that asthmatic women have a poorer quality of life and increased utilization of healthcare compared to their male counterparts despite similar medical treatment and baseline pulmonary function. Research continues to explore hypotheses for these differences including the potential influences of the female sex hormones, altered perception of airflow obstruction, increased bronchial hyper-responsiveness, and medication compliance and technique. However, no single explanation has been able to fully explain the disparities. women are more likely to be diagnosed with asthma and suffer greater morbidity than men. The physiologic mechanisms for these differences are not well understood. Understanding sex-related differences in asthma and providing patients with education geared toward these disparities are important in establishing effective, individualized asthma management strategies for all patients.

Females are the brighter sex: Differences in external fluorescence across sexes and life stages of a crab spider.

PubMed

Brandt, Erin E; Masta, Susan E

2017-01-01

Fluorescence is increasingly recognized to be widespread in nature. In particular, some arachnids fluoresce externally, and in spiders the hemolymph fluoresces. In this study, we examined the external fluorescence and the fluorophores of different sexes and life stages of the crab spider Misumena vatia (Clerk 1757), a sit-and-wait predator that feeds on insects as they visit flowers. We designed novel instrumentation to measure external fluorescence in whole specimens. We found that although males and females possess internal fluorophores with similar properties, the external expression of fluorescence varies across sexes and life stages. Spiders fluoresce brightly as immatures. Females maintain their brightness to adulthood, whereas males become increasingly dim as they mature. We suggest that external fluorescence likely contributes to visual signaling in these animals, and that it differs between the sexes as a result of differences in foraging ecology and behavior.

Females are the brighter sex: Differences in external fluorescence across sexes and life stages of a crab spider

PubMed Central

Brandt, Erin E.

2017-01-01

Fluorescence is increasingly recognized to be widespread in nature. In particular, some arachnids fluoresce externally, and in spiders the hemolymph fluoresces. In this study, we examined the external fluorescence and the fluorophores of different sexes and life stages of the crab spider Misumena vatia (Clerk 1757), a sit-and-wait predator that feeds on insects as they visit flowers. We designed novel instrumentation to measure external fluorescence in whole specimens. We found that although males and females possess internal fluorophores with similar properties, the external expression of fluorescence varies across sexes and life stages. Spiders fluoresce brightly as immatures. Females maintain their brightness to adulthood, whereas males become increasingly dim as they mature. We suggest that external fluorescence likely contributes to visual signaling in these animals, and that it differs between the sexes as a result of differences in foraging ecology and behavior. PMID:28467416

Neuroendocrine correlates of sex-role reversal in barred buttonquails

PubMed Central

2016-01-01

Sex differences in brain structure and behaviour are well documented among vertebrates. An excellent model exploring the neural mechanisms of sex differences in behaviour is represented by sex-role-reversed species. In the majority of bird species, males compete over access to mates and resources more strongly than do females. It is thought that the responsible brain regions are therefore more developed in males than in females. Because these behaviours and brain regions are activated by androgens, males usually have increased testosterone levels during breeding. Therefore, in species with sex-role reversal, certain areas of the female brain should be more developed or steroid hormone profiles should be sexually reversed. Here, I studied circulating hormone levels and gene expression of steroid hormone receptors and aromatase in a captive population of barred buttonquails (Turnix suscitator). While females performed courtship and agonistic behaviours, there was no evidence for sexually reversed hormone profiles. However, I found female-biased sex differences in gene expression of androgen receptors in several hypothalamic and limbic brain regions that were already in place at hatching. Such sex differences are not known from non-sex-role-reversed species. These data suggest that increased neural sensitivity to androgens could be involved in the mechanisms mediating sex-role-reversed behaviours. PMID:27881754

Attitudes Toward Same-Sex Parenting: An Effect of Gender.

PubMed

Webb, Stephanie N; Chonody, Jill M; Kavanagh, Phillip S

2017-01-01

The definition of family in Australia has been continuously changing over the past four decades. The 21 st century has brought with it various images of family, with an increase of awareness to same-sex families; however, the acceptance of such family structures does not appear to be widespread and is often determined by sex. Substantive literature demonstrates differences between men and women in attitudes toward same-sex parenting, with theory suggesting that gender role norms may explain this. Despite large efforts to determine sex differences in attitudes toward same-sex parenting, little research, and even less in Australia, has been done to investigate whether there are differences in reasons behind negative attitudes toward same-sex parenting between men and women. To further this understanding, an Australian sample (N= 790) ranging in age from 18-78 completed a survey regrading attitudes toward same-sex parenting, in addition to relevant demographic information. Participants reported more positive attitudes about parenting by lesbians as compared to parenting by gay men. Reasons behind attitudes toward same-sex parenting also differed between males and females. Results suggested that the impact of socially prescribed gender norms may affect prejudice toward same-sex families. Despite an increase in tolerance for sexual minorities recently, policies that continue to discriminate against same-sex parenting rights demonstrates the importance of continuing to identify potential influences of same-sex family prejudice to reduce the potentially negative impacts associated with the prejudice.

Childhood Adversity, Daily Stress, and Marital Strain in Same-Sex and Different-Sex Marriages

PubMed Central

Donnelly, Rachel; Umberson, Debra; Kroeger, Rhiannon A.

2017-01-01

Childhood adversity has enduring consequences for individuals throughout life, including increased reactivity to stress that may contribute to marital strain in adulthood. Past research on gendered experiences of heterosexual spouses raises questions about how the influence of childhood adversity might differ for men and women in same-sex marriages. We analyze dyadic diary data from 756 individuals in 106 male same-sex, 157 female same-sex, and 115 different-sex marriages to consider how childhood adversity moderates the association between daily stress and marital strain. Results suggest that the negative consequences of daily stress for marital strain are amplified by past childhood adversity with variation for men and women in same- and different-sex unions, such that women and those in same-sex marriages may experience some protection from the adverse consequences of childhood adversity.

Sex differences in stress-related psychiatric disorders: neurobiological perspectives.

PubMed

Bangasser, Debra A; Valentino, Rita J

2014-08-01

Stress is associated with the onset and severity of several psychiatric disorders that occur more frequently in women than men, including posttraumatic stress disorder (PTSD) and depression. Patients with these disorders present with dysregulation of several stress response systems, including the neuroendocrine response to stress, corticolimbic responses to negatively valenced stimuli, and hyperarousal. Thus, sex differences within their underlying circuitry may explain sex biases in disease prevalence. This review describes clinical studies that identify sex differences within the activity of these circuits, as well as preclinical studies that demonstrate cellular and molecular sex differences in stress responses systems. These studies reveal sex differences from the molecular to the systems level that increase endocrine, emotional, and arousal responses to stress in females. Exploring these sex differences is critical because this research can reveal the neurobiological underpinnings of vulnerability to stress-related psychiatric disorders and guide the development of novel pharmacotherapies. Copyright © 2014 Elsevier Inc. All rights reserved.

Sex Differences in Stress-Related Psychiatric Disorders: Neurobiological Perspectives

PubMed Central

Bangasser, Debra A.; Valentino, Rita J.

2014-01-01

Stress is associated with the onset and severity of several psychiatric disorders that occur more frequently in women than men, including posttraumatic stress disorder (PTSD) and depression. Patients with these disorders present with dysregulation of several stress response systems, including the neuroendocrine response to stress, corticolimbic responses to negatively valenced stimuli, and hyperarousal. Thus, sex differences within their underlying circuitry may explain sex biases in disease prevalence. This review describes clinical studies that identify sex differences within the activity of these circuits, as well as preclinical studies that demonstrate cellular and molecular sex differences in stress responses systems. These studies reveal sex differences from the molecular to the systems level that increase endocrine, emotional, and arousal responses to stress in females. Exploring these sex differences is critical because this research can reveal the neurobiological underpinnings of vulnerability to stress-related psychiatric disorders and guide the development of novel pharmacotherapies. PMID:24726661

Sex-related responses after traumatic brain injury: Considerations for preclinical modeling.

PubMed

Späni, Claudia B; Braun, David J; Van Eldik, Linda J

2018-05-18

Traumatic brain injury (TBI) has historically been viewed as a primarily male problem, since men are more likely to experience a TBI because of more frequent participation in activities that increase risk of head injuries. This male bias is also reflected in preclinical research where mostly male animals have been used in basic and translational science. However, with an aging population in which TBI incidence is increasingly sex-independent due to falls, and increasing female participation in high-risk activities, the attention to potential sex differences in TBI responses and outcomes will become more important. These considerations are especially relevant in designing preclinical animal models of TBI that are more predictive of human responses and outcomes. This review characterizes sex differences following TBI with a special emphasis on the contribution of the female sex hormones, progesterone and estrogen, to these differences. This information is potentially important in developing and customizing TBI treatments. Copyright © 2018 Elsevier Inc. All rights reserved.

FMRI to probe sex-related differences in brain function with multitasking

PubMed Central

Tschernegg, Melanie; Neuper, Christa; Schmidt, Reinhold; Wood, Guilherme; Kronbichler, Martin; Fazekas, Franz; Enzinger, Christian

2017-01-01

Background Although established as a general notion in society, there is no solid scientific foundation for the existence of sex-differences in multitasking. Reaction time and accuracy in dual task conditions have an inverse relationship relative to single task, independently from sex. While a more disseminated network, parallel to decreasing accuracy and reaction time has been demonstrated in dual task fMRI studies, little is known so far whether there exist respective sex-related differences in activation. Methods We subjected 20 women (mean age = 25.45; SD = 5.23) and 20 men (mean age = 27.55; SD = 4.00) to a combined verbal and spatial fMRI paradigm at 3.0T to assess sex-related skills, based on the assumption that generally women better perform in verbal tasks while men do better in spatial tasks. We also obtained behavioral tests for verbal and spatial intelligence, attention, executive functions, and working memory. Results No differences between women and men were observed in behavioral measures of dual-tasking or cognitive performance. Generally, brain activation increased with higher task load, mainly in the bilateral inferior and prefrontal gyri, the anterior cingulum, thalamus, putamen and occipital areas. Comparing sexes, women showed increased activation in the inferior frontal gyrus in the verbal dual-task while men demonstrated increased activation in the precuneus and adjacent visual areas in the spatial task. Conclusion Against the background of equal cognitive and behavioral dual-task performance in both sexes, we provide first evidence for sex-related activation differences in functional networks for verbal and spatial dual-tasking. PMID:28759619

FMRI to probe sex-related differences in brain function with multitasking.

PubMed

Tschernegg, Melanie; Neuper, Christa; Schmidt, Reinhold; Wood, Guilherme; Kronbichler, Martin; Fazekas, Franz; Enzinger, Christian; Koini, Marisa

2017-01-01

Although established as a general notion in society, there is no solid scientific foundation for the existence of sex-differences in multitasking. Reaction time and accuracy in dual task conditions have an inverse relationship relative to single task, independently from sex. While a more disseminated network, parallel to decreasing accuracy and reaction time has been demonstrated in dual task fMRI studies, little is known so far whether there exist respective sex-related differences in activation. We subjected 20 women (mean age = 25.45; SD = 5.23) and 20 men (mean age = 27.55; SD = 4.00) to a combined verbal and spatial fMRI paradigm at 3.0T to assess sex-related skills, based on the assumption that generally women better perform in verbal tasks while men do better in spatial tasks. We also obtained behavioral tests for verbal and spatial intelligence, attention, executive functions, and working memory. No differences between women and men were observed in behavioral measures of dual-tasking or cognitive performance. Generally, brain activation increased with higher task load, mainly in the bilateral inferior and prefrontal gyri, the anterior cingulum, thalamus, putamen and occipital areas. Comparing sexes, women showed increased activation in the inferior frontal gyrus in the verbal dual-task while men demonstrated increased activation in the precuneus and adjacent visual areas in the spatial task. Against the background of equal cognitive and behavioral dual-task performance in both sexes, we provide first evidence for sex-related activation differences in functional networks for verbal and spatial dual-tasking.

Spatiotemporal mapping of sex differences during attentional processing.

PubMed

Neuhaus, Andres H; Opgen-Rhein, Carolin; Urbanek, Carsten; Gross, Melanie; Hahn, Eric; Ta, Thi Minh Tam; Koehler, Simone; Dettling, Michael

2009-09-01

Functional neuroimaging studies have increasingly aimed at approximating neural substrates of human cognitive sex differences elicited by visuospatial challenge. It has been suggested that females and males use different behaviorally relevant neurocognitive strategies. In females, greater right prefrontal cortex activation has been found in several studies. The spatiotemporal dynamics of neural events associated with these sex differences is still unclear. We studied 22 female and 22 male participants matched for age, education, and nicotine with 29-channel-electroencephalogram recorded under a visual selective attention paradigm, the Attention Network Test. Visual event-related potentials (ERP) were topographically analyzed and neuroelectric sources were estimated. In absence of behavioral differences, ERP analysis revealed a novel frontal-occipital second peak of visual N100 that was significantly increased in females relative to males. Further, in females exclusively, a corresponding central ERP component at around 220 ms was found; here, a strong correlation between stimulus salience and sex difference of the central ERP component amplitude was observed. Subsequent source analysis revealed increased cortical current densities in right rostral prefrontal (BA 10) and occipital cortex (BA 19) in female subjects. This is the first study to report on a tripartite association between sex differences in ERPs, visual stimulus salience, and right prefrontal cortex activation during attentional processing. 2009 Wiley-Liss, Inc.

Sex Differences in the Association between Foetal Growth and Child Attention at Age Four: Specific Vulnerability of Girls

ERIC Educational Resources Information Center

Murray, Elizabeth; Matijasevich, Alicia; Santos, Iná S.; Barros, Aluísio J. D.; Anselmi, Luciana; Barros, Fernando C.; Stein, Alan

2015-01-01

Background: Recent evidence suggests that impaired foetal growth may provide an early indication of increased risk of child attention problems. However, despite both foetal growth and child attention problems differing by sex, few studies have examined sex differences in this association. Furthermore, no studies have been conducted in low- and…

Sex-based Differences in Common Sports Injuries.

PubMed

Carter, Cordelia W; Ireland, Mary Lloyd; Johnson, Anthony E; Levine, William N; Martin, Scott; Bedi, Asheesh; Matzkin, Elizabeth G

2018-05-28

The patient's sex plays an important role in mediating the risk for, and experience of, disease. Injuries of the musculoskeletal system are no exception to this phenomenon. Increasing evidence shows that the incidence, clinical presentation, and treatment outcomes for male and female patients with common sports injuries may vary widely. Stress fracture, which is associated with the female athlete triad, is a sports injury with known sex-based differences. Other common sports-related injuries may also have distinct sex-based differences. Understanding these differences is important to optimize each patient's musculoskeletal care.

The effect of equalizing landing task demands on sex differences in lower extremity energy absorption.

PubMed

Montgomery, Melissa M; Shultz, Sandra J; Schmitz, Randy J

2014-08-01

Less lean mass and strength may result in greater relative task demands on females compared to males when landing from a standardized height and could explain sex differences in energy absorption strategies. We compared the magnitude of sex differences in energy absorption when task demands were equalized relative to the amount of lower extremity lean mass available to dissipate kinetic energy upon landing. Male-female pairs (n=35) were assessed for lower extremity lean mass with dual-energy X-ray absorptiometry. Relative task demands were calculated when landing from a standardized height. Based on the difference in lower extremity lean mass within each pair, task demands were equalized by increasing the drop height for males. Joint energetics were measured while landing from the two heights. Multivariate repeated measures ANOVAs compared the magnitude of sex differences in joint energetics between conditions. The multivariate test for absolute energy absorption was significant (P<0.01). The magnitude of sex difference in energy absorption was greater at the hip and knee (both P<0.01), but not the ankle (P=0.43) during the equalized condition compared to the standardized and exaggerated conditions (all P<0.01). There was no difference in the magnitude of sex differences between equalized, standardized and exaggerated conditions for relative energy absorption (P=0.18). Equalizing task demands increased the difference in absolute hip and knee energy absorption between sexes, but had no effect on relative joint contributions to total energy absorption. Sex differences in energy absorption are likely influenced by factors other than differences in relative task demands. Copyright © 2014 Elsevier Ltd. All rights reserved.

The effects of death reminders on sex differences in prejudice toward gay men and lesbians.

PubMed

Webster, Russell J; Saucier, Donald A

2011-01-01

Terror management research shows that death reminders (mortality salience) increase prejudice toward worldview violators. Two studies investigated whether death reminders exacerbated differences in heterosexual men's and women's reports of sexual prejudice (negative attitudes based on sexual orientation). Results showed that following death reminders, sex differences in anti-gay discrimination and affective prejudice toward gay men (but not toward lesbians) were larger, and that these increased sex differences were mediated by gender role beliefs. The current studies suggest that researchers may attenuate the effects of death reminders by lessening the perceived worldview violation in addition to alleviating the existential terror of death.

Sex-specific phenotypes of hyperthyroidism and hypothyroidism in mice.

PubMed

Rakov, Helena; Engels, Kathrin; Hönes, Georg Sebastian; Strucksberg, Karl-Heinz; Moeller, Lars Christian; Köhrle, Josef; Zwanziger, Denise; Führer, Dagmar

2016-01-01

Thyroid dysfunction is more common in the female population, however, the impact of sex on disease characteristics has rarely been addressed. Using a murine model, we asked whether sex has an influence on phenotypes, thyroid hormone status, and thyroid hormone tissue response in hyper- and hypothyroidism. Hypo- and hyperthyroidism were induced in 5-month-old female and male wildtype C57BL/6N mice, by LoI/MMI/ClO4 (-) or T4 i.p. treatment over 7 weeks, and control animals underwent sham treatment (N = 8 animals/sex/treatment). Animals were investigated for impact of sex on body weight, food and water intake, body temperature, heart rate, behaviour (locomotor activity, motor coordination, and strength), liver function, serum thyroid hormone status, and cellular TH effects on gene expression in brown adipose tissue, heart, and liver. Male and female mice showed significant differences in behavioural, functional, metabolic, biochemical, and molecular traits of hyper- and hypothyroidism. Hyperthyroidism resulted in increased locomotor activity in female mice but decreased muscle strength and motor coordination preferably in male animals. Hypothyroidism led to increased water intake in male but not female mice and significantly higher serum cholesterol in male mice. Natural sex differences in body temperature, body weight gain, food and water intake were preserved under hyperthyroid conditions. In contrast, natural sex differences in heart rate disappeared with TH excess and deprivation. The variations of hyper- or hypothyroid traits of male and female mice were not explained by classical T3/T4 serum state. TH serum concentrations were significantly increased in female mice under hyperthyroidism, but no sex differences were found under eu- or hypothyroid conditions. Interestingly, analysis of expression of TH target genes and TH transporters revealed little sex dependency in heart, while sex differences in target genes were present in liver and brown adipose tissue in line with altered functional and metabolic traits of hyper- and hypothyroidism. These data demonstrate that the phenotypes of hypo- and hyperthyroidism differ between male and female mice and indicate that sex is an important modifier of phenotypic manifestations.

Sex-specific developmental models for Creophilus maxillosus (L.) (Coleoptera: Staphylinidae): searching for larger accuracy of insect age estimates.

PubMed

Frątczak-Łagiewska, Katarzyna; Matuszewski, Szymon

2018-05-01

Differences in size between males and females, called the sexual size dimorphism, are common in insects. These differences may be followed by differences in the duration of development. Accordingly, it is believed that insect sex may be used to increase the accuracy of insect age estimates in forensic entomology. Here, the sex-specific differences in the development of Creophilus maxillosus were studied at seven constant temperatures. We have also created separate developmental models for males and females of C. maxillosus and tested them in a validation study to answer a question whether sex-specific developmental models improve the accuracy of insect age estimates. Results demonstrate that males of C. maxillosus developed significantly longer than females. The sex-specific and general models for the total immature development had the same optimal temperature range and similar developmental threshold but different thermal constant K, which was the largest in the case of the male-specific model and the smallest in the case of the female-specific model. Despite these differences, validation study revealed just minimal and statistically insignificant differences in the accuracy of age estimates using sex-specific and general thermal summation models. This finding indicates that in spite of statistically significant differences in the duration of immature development between females and males of C. maxillosus, there is no increase in the accuracy of insect age estimates while using the sex-specific thermal summation models compared to the general model. Accordingly, this study does not support the use of sex-specific developmental data for the estimation of insect age in forensic entomology.

Sex differences in ischemic stroke sensitivity are influenced by gonadal hormones, not by sex chromosome complement.

PubMed

Manwani, Bharti; Bentivegna, Kathryn; Benashski, Sharon E; Venna, Venugopal Reddy; Xu, Yan; Arnold, Arthur P; McCullough, Louise D

2015-02-01

Epidemiologic studies have shown sex differences in ischemic stroke. The four core genotype (FCG) mouse model, in which the testes determining gene, Sry, has been moved from Y chromosome to an autosome, was used to dissociate the effects of sex hormones from sex chromosome in ischemic stroke outcome. Middle cerebral artery occlusion (MCAO) in gonad intact FCG mice revealed that gonadal males (XXM and XYM) had significantly higher infarct volumes as compared with gonadal females (XXF and XYF). Serum testosterone levels were equivalent in adult XXM and XYM, as was serum estrogen in XXF and XYF mice. To remove the effects of gonadal hormones, gonadectomized FCG mice were subjected to MCAO. Gonadectomy significantly increased infarct volumes in females, while no change was seen in gonadectomized males, indicating that estrogen loss increases ischemic sensitivity. Estradiol supplementation in gonadectomized FCG mice rescued this phenotype. Interestingly, FCG male mice were less sensitive to effects of hormones. This may be due to enhanced expression of the transgene Sry in brains of FCG male mice. Sex differences in ischemic stroke sensitivity appear to be shaped by organizational and activational effects of sex hormones, rather than sex chromosomal complement.

Sex-specific responses to climate change in plants alter population sex ratio and performance.

PubMed

Petry, William K; Soule, Judith D; Iler, Amy M; Chicas-Mosier, Ana; Inouye, David W; Miller, Tom E X; Mooney, Kailen A

2016-07-01

Males and females are ecologically distinct in many species, but whether responses to climate change are sex-specific is unknown. We document sex-specific responses to climate change in the plant Valeriana edulis (valerian) over four decades and across its 1800-meter elevation range. Increased elevation was associated with increased water availability and female frequency, likely owing to sex-specific water use efficiency and survival. Recent aridification caused male frequency to move upslope at 175 meters per decade, a rate of trait shift outpacing reported species' range shifts by an order of magnitude. This increase in male frequency reduced pollen limitation and increased seedset. Coupled with previous studies reporting sex-specific arthropod communities, these results underscore the importance of ecological differences between the sexes in mediating biological responses to climate change. Copyright © 2016, American Association for the Advancement of Science.

Sexual Differentiation of Motivation: a novel mechanism?

PubMed Central

Becker, Jill B.

2009-01-01

Sex differences in motivation are apparent for the motivation to engage in sexual behavior, the motivation to take drugs of abuse, and the motivation to engage in parental behavior. In both males and females there is an increase in NAcc DA associated with motivated behaviors. Here it proposed that sex differences in the regulation of DA activity in the ascending mesolimbic projections may underlie sex differences in motivation. In particular, sex differences in the neuroendocrine regulation of this brain system plays a role in the expression of sex differences in motivated behaviors. Here it is proposed that sexual differentiation of motivation is mediated, at least in part, by a novel mechanism in which ovarian hormones secreted at puberty in the female actively feminize the DA system. PMID:19446081

Sex differences in drug addiction and response to exercise intervention: from human to animal studies

PubMed Central

Zhou, Yuehui; Zhao, Min; Zhou, Chenglin; Li, Rena

2015-01-01

Accumulated research supports the idea that exercise could be an option of potential prevention and treatment for drug addiction. During the past few years, there has been increased interest in investigating of sex differences in exercise and drug addiction. This demonstrates that sex-specific exercise intervention strategies may be important for preventing and treating drug addiction in men and women. However, little is known about how and why sex differences are found when doing exercise-induced interventions for drug addiction. In this review, we included both animal and human that pulled subjects from a varied age demographic, as well as neurobiological mechanisms that may highlight the sex-related differences in these potential to assess the impact of sex-specific roles in drug addiction and exercise therapies. PMID:26182835

The sex ratio at birth in France was unchanged 9months after the 1998 FIFA World Cup.

PubMed

Masukume, Gwinyai; Grech, Victor

2016-08-01

Positive psychological phenomena such as increased feelings of belonging linked to hosting the FIFA World Cup were observed in France 1998 and South Africa 2010. Approximately nine months after South Africa hosted the 2010 World Cup the sex ratio at birth increased significantly. Given the similarity of positive psychological phenomena between the two countries, this study sought to determine if the sex ratio at birth increased in France circa nine months after the 1998 World Cup. Anonymized publicly available live birth data from 1994 to 2004 inclusive was obtained from the Insee (Institut National de la Statistique et des Etudes/Économiques - National Institute of Statistics and Economic Studies). For statistical analysis, chi-squared tests were used. The sex ratio at birth for March and April 1999 did not differ significantly from that of the rest of same period from 1996 to 2000 (p=0.558), there was also no significant difference for February and March 1999. The sex ratio at birth did not increase in France after it hosted the 1998 World Cup. Possible reasons why the sex ratio at birth did not increase as it did in South Africa include a higher French prevalence of modern contraceptive use and a different kind/level of excitement for the World Cup in France since it has previously hosted large international sports tournaments. The influence of the World Cup on the sex ratio at birth depends on the context of a specific country. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Sex differences and stress across the lifespan

PubMed Central

Bale, Tracy L; Epperson, C Neill

2015-01-01

Sex differences in stress responses can be found at all stages of life and are related to both the organizational and activational effects of gonadal hormones and to genes on the sex chromosomes. As stress dysregulation is the most common feature across neuropsychiatric diseases, sex differences in how these pathways develop and mature may predict sex-specific periods of vulnerability to disruption and increased disease risk or resilience across the lifespan. The aging brain is also at risk to the effects of stress, where the rapid decline of gonadal hormones in women combined with cellular aging processes promote sex biases in stress dysregulation. In this Review, we discuss potential underlying mechanisms driving sex differences in stress responses and their relevance to disease. Although stress is involved in a much broader range of diseases than neuropsychiatric ones, we highlight here this area and its examples across the lifespan. PMID:26404716

Sex differences and stress across the lifespan.

PubMed

Bale, Tracy L; Epperson, C Neill

2015-10-01

Sex differences in stress responses can be found at all stages of life and are related to both the organizational and activational effects of gonadal hormones and to genes on the sex chromosomes. As stress dysregulation is the most common feature across neuropsychiatric diseases, sex differences in how these pathways develop and mature may predict sex-specific periods of vulnerability to disruption and increased disease risk or resilience across the lifespan. The aging brain is also at risk to the effects of stress, where the rapid decline of gonadal hormones in women combined with cellular aging processes promote sex biases in stress dysregulation. In this Review, we discuss potential underlying mechanisms driving sex differences in stress responses and their relevance to disease. Although stress is involved in a much broader range of diseases than neuropsychiatric ones, we highlight here this area and its examples across the lifespan.

Sex differences in giraffe foraging behavior at two spatial scales.

PubMed

Ginnett, T F; Demment, Montague W

1997-04-01

We test predictions about differences in the foraging behaviors of male and female giraffes (Giraffa camelopardalis tippelskirchi Matchie) that derive from a hypothesis linking sexual size dimorphism to foraging behavior. This body-size hypothesis predicts that males will exhibit specific behaviors that increase their dry-matter intake rate relative to females. Foraging behavior was examined at two hierarchical levels corresponding to two spatial and temporal scales, within patches and within habitats. Patches are defined as individual trees or shrubs and habitats are defined as collections of patches within plant communities. Males were predicted to increase dry-matter intake rate within patches by taking larger bites, cropping bites more quickly, chewing less, and chewing faster. Within habitats, males were expected to increase intake rate by increasing the proportion of foraging time devoted to food ingestion as opposed to inter-patch travel time and vigilance. The predictions were tested in a free-ranging population of giraffes in Mikumi National Park, Tanzania. Males spent less total time foraging than females but allocated a greater proportion of their foraging time to forage ingestion as opposed to travel between patches. There was no sex difference in rumination time but males spent more time in activities other than foraging and rumination, such as walking. Within patches, males took larger bites than females, but females cropped bites more quickly and chewed faster. Males had longer per-bite handling times than females but had shorter handling times per gram of intake. Within habitats, males had longer average patch residence times but there was no significant sex difference in inter-patch travel times. There was no overall difference between sexes in vigilance while foraging, although there were significant sex by habitat and sex by season interactions. Although not all the predictions were confirmed, overall the results agree qualitatively with the body-size hypothesis. Sex-related differences in foraging behavior led to greater estimated intake rates for males at the within-patch and within-habitat scales.

Effects of one's sex and sex hormones on sympathetic responses to chemoreflex activation.

PubMed

Usselman, Charlotte W; Steinback, Craig D; Shoemaker, J Kevin

2016-03-01

What is the topic of this review? This review summarizes sex-dependent differences in the sympathetic responses to chemoreflex activation, with a focus on the role of circulating sex hormones on the sympathetic outcomes. What advances does it highlight? The importance of circulating sex hormones for the regulation of sympathetic nerve activity in humans has only recently begun to be elucidated, and few studies have examined this effect during chemoreflex regulation. We review recent studies indicating that changes in circulating sex hormones are associated with alterations to chemoreflex-driven increases in sympathetic activity and highlight those areas which require further study. Sex-dependent differences in baseline sympathetic nerve activity are established, but little information exists on the influence of sex on sympathetic activation during chemoreflex stimulation. In this article, we review the evidence for the effect of sex on chemoreflex-driven increases in sympathetic nerve activity. We also review recent studies which indicate that changes in circulating sex hormones, as initiated by the menstrual cycle and hormonal contraceptive use, elicit notable changes in the muscle sympathetic activation during chemoreflex stimulation. © 2015 The Authors. Experimental Physiology © 2015 The Physiological Society.

Increased HDL cholesterol levels in mice with XX versus XY sex chromosomes

PubMed Central

Link, Jenny C.; Chen, Xuqi; Prien, Christopher; Borja, Mark S.; Hammerson, Bradley; Oda, Michael N.; Arnold, Arthur P.; Reue, Karen

2015-01-01

Objective The molecular mechanisms underlying sex differences in dyslipidemia are poorly understood. We aimed to distinguish genetic and hormonal regulators of sex differences in plasma lipid levels. Approach and Results We assessed the role of gonadal hormones and sex chromosome complement on lipid levels using the Four Core Genotypes mouse model (XX females, XX males, XY females, and XY males). In gonadally intact mice fed a chow diet, lipid levels were influenced by both male–female gonadal sex and XX–XY chromosome complement. Gonadectomy of adult mice revealed that the male–female differences are dependent on acute effects of gonadal hormones. In both intact and gonadectomized animals, XX mice had higher HDL cholesterol (HDL-C) levels than XY mice, regardless of male–female sex. Feeding a cholesterol-enriched diet produced distinct patterns of sex differences in lipid levels compared to a chow diet, revealing the interaction of gonadal and chromosomal sex with diet. Notably, under all dietary and gonadal conditions, HDL-C levels were higher in mice with two X chromosomes compared to mice with an X and Y chromosome. By generating mice with XX, XY and XXY chromosome complements, we determined that the presence of two X chromosomes, and not the absence of the Y chromosome, influences HDL-C concentration. Conclusions We demonstrate that having two X chromosomes versus an X and Y chromosome complement drives sex differences in HDL-C. It is conceivable that increased expression of genes escaping X-inactivation in XX mice regulates downstream processes to establish sexual dimorphism in plasma lipid levels. PMID:26112012

Increased high-density lipoprotein cholesterol levels in mice with XX versus XY sex chromosomes.

PubMed

Link, Jenny C; Chen, Xuqi; Prien, Christopher; Borja, Mark S; Hammerson, Bradley; Oda, Michael N; Arnold, Arthur P; Reue, Karen

2015-08-01

The molecular mechanisms underlying sex differences in dyslipidemia are poorly understood. We aimed to distinguish genetic and hormonal regulators of sex differences in plasma lipid levels. We assessed the role of gonadal hormones and sex chromosome complement on lipid levels using the four core genotypes mouse model (XX females, XX males, XY females, and XY males). In gonadally intact mice fed a chow diet, lipid levels were influenced by both male-female gonadal sex and XX-XY chromosome complement. Gonadectomy of adult mice revealed that the male-female differences are dependent on acute effects of gonadal hormones. In both intact and gonadectomized animals, XX mice had higher HDL cholesterol (HDL-C) levels than XY mice, regardless of male-female sex. Feeding a cholesterol-enriched diet produced distinct patterns of sex differences in lipid levels compared with a chow diet, revealing the interaction of gonadal and chromosomal sex with diet. Notably, under all dietary and gonadal conditions, HDL-C levels were higher in mice with 2 X chromosomes compared with mice with an X and Y chromosome. By generating mice with XX, XY, and XXY chromosome complements, we determined that the presence of 2 X chromosomes, and not the absence of the Y chromosome, influences HDL-C concentration. We demonstrate that having 2 X chromosomes versus an X and Y chromosome complement drives sex differences in HDL-C. It is conceivable that increased expression of genes escaping X-inactivation in XX mice regulates downstream processes to establish sexual dimorphism in plasma lipid levels. © 2015 American Heart Association, Inc.

Sex differences in drug addiction and response to exercise intervention: From human to animal studies.

PubMed

Zhou, Yuehui; Zhao, Min; Zhou, Chenglin; Li, Rena

2016-01-01

Accumulated research supports the idea that exercise could be an option of potential prevention and treatment for drug addiction. During the past few years, there has been increased interest in investigating of sex differences in exercise and drug addiction. This demonstrates that sex-specific exercise intervention strategies may be important for preventing and treating drug addiction in men and women. However, little is known about how and why sex differences are found when doing exercise-induced interventions for drug addiction. In this review, we included both animal and human that pulled subjects from a varied age demographic, as well as neurobiological mechanisms that may highlight the sex-related differences in these potential to assess the impact of sex-specific roles in drug addiction and exercise therapies. Copyright © 2015 Elsevier Inc. All rights reserved.

Trends in Gender Differences in Poverty: 1950-1980.

ERIC Educational Resources Information Center

McLanahan, Sara; And Others

In 1980 the poverty rates for women were about one and a half times greater than those for men. Between 1950 and 1980 the degree of inequality between the sexes increased by about 30 percent. This paper describes those trends, focusing on the sex of the individual rather than sex of the household head. It also examines differences in the risk of…

The Influence of Partner Status and Sexual Behavior on College Women's Consent Communication and Feelings.

PubMed

Marcantonio, Tiffany; Jozkowski, Kristen N; Wiersma-Mosley, Jackie

2018-05-09

Sexual consent has permeated mainstream discourse as a mechanism used to decrease rates of sexual assault and increase sex-positive communication. Women's external consent behaviors are frequently examined; however, research exploring their internal consent and feelings associated with sexual activity are understudied. The purpose of this study was to understand how partner status and sexual behavior at most recent sexual activity influence women's external/internal consent and feelings during sexual activity. Three-hundred and ninety women completed a survey on consent, partner status, and most recent sexual behavior. Internal and external consent differed by partner status for women who engaged in vaginal-penile sex, but not genital and oral sex. Feelings associated with the sexual act were different within each behavior group and partner status. Women with a serious dating partner reported stronger feelings related to sexual activity, higher internal consent feelings, and increased use of non-verbal external consent cues. Partner status appears to influence factors of interest for vaginal-penile sex, but not genital and oral sex. Findings from this study can inform prevention efforts to increase sex-positive communication around consent.

A heads up on concussions: are there sex-related differences?

PubMed

Brook, Emily M; Luo, Xuan; Curry, Emily J; Matzkin, Elizabeth G

2016-01-01

Head injuries are a major concern for physicians in athletes of all ages. Specifically, sports-related concussions are becoming an all-too-common injury among female athletes. The incidence of concussions among female athletes has likely increased over the past few decades because of an increase in sports participation afforded by Title IX. It would be useful for physicians to have general knowledge of concussions and their potential sex-related differences. This review article summarizes the current body of research concerning sex-related differences in concussion epidemiology and outcomes. A literature search was performed using PubMed and included all articles published from 1993 to present, with a predominant focus on research conducted over the past fifteen years. Additional articles were found using the bibliography from articles found through the PubMed search. Several articles have compared incidence, severity of neurological deficit, constellation of symptoms, and length of recovery post-concussion in males and females. However, the literature does not unanimously support a significant sex-related difference in concussions. Lack of consensus in the literature can be attributed to differences between patient populations, different tools used to study concussions, including subjective or objective measures, and differences in mechanisms of injury. We conclude that concussions are a serious injury in both male and female athletes, and physicians should have a very high index of suspicion regardless of sex, because there currently is not sufficient consensus in the literature to institute sex-related changes to concussion management. Current research may suggest a sex-related difference pertaining to sports-related concussions, but further evaluation is needed on this topic.

Patterns and causes of gender differences in smoking.

PubMed

Waldron, I

1991-01-01

In the early twentieth century in the United States and other Western countries, women were much less likely than men to smoke cigarettes, due in part to widespread social disapproval of women's smoking. During the mid-twentieth century, growing social acceptance of women's smoking contributed to increased smoking adoption by women. Increased social acceptance of women's smoking was part of a general liberalization of norms concerning women's behavior, reflecting increasing equality between the sexes. These historical trends were due in part to increases in women's employment. However, in the contemporary period employment appears to have little or no effect on women's smoking. Sex role norms and general expectations concerning gender-appropriate behavior have had a variety of effects on gender differences in smoking. First, general characteristics of traditional sex roles, including men's greater social power and generally greater restrictions on women's behavior, contributed to widespread social pressures against women's smoking. Second, traditional sex role norms and expectations have fostered gender differences in personal characteristics and experiences which influence smoking adoption. For example, rebelliousness has been more expected and accepted for males, and greater rebelliousness among adolescent males has contributed to greater smoking adoption by males. Finally, certain aspects of sex roles have contributed to gender differences in appraisal of the costs and benefits of smoking. For example, physical attractiveness is emphasized more for females and the contemporary beauty ideal is very slender, so females are more likely to view weight control as a benefit of smoking. Several other hypotheses concerning the causes of gender differences in smoking are not supported by the available evidence. For example, it appears that women's generally greater concern with health has not contributed significantly to gender differences in the prevalence of smoking. Similarly, it appears that sex differences in physiological responses to smoking have made only minor contributions to gender differences in smoking adoption or cessation.

Sex-related differences in sleep slow wave activity in major depressive disorder: a high-density EEG investigation.

PubMed

Plante, David T; Landsness, Eric C; Peterson, Michael J; Goldstein, Michael R; Riedner, Brady A; Wanger, Timothy; Guokas, Jeffrey J; Tononi, Giulio; Benca, Ruth M

2012-09-18

Sleep disturbance plays an important role in major depressive disorder (MDD). Prior investigations have demonstrated that slow wave activity (SWA) during sleep is altered in MDD; however, results have not been consistent across studies, which may be due in part to sex-related differences in SWA and/or limited spatial resolution of spectral analyses. This study sought to characterize SWA in MDD utilizing high-density electroencephalography (hdEEG) to examine the topography of SWA across the cortex in MDD, as well as sex-related variation in SWA topography in the disorder. All-night recordings with 256 channel hdEEG were collected in 30 unipolar MDD subjects (19 women) and 30 age and sex-matched control subjects. Spectral analyses of SWA were performed to determine group differences. SWA was compared between MDD and controls, including analyses stratified by sex, using statistical non-parametric mapping to correct for multiple comparisons of topographic data. As a group, MDD subjects demonstrated significant increases in all-night SWA primarily in bilateral prefrontal channels. When stratified by sex, MDD women demonstrated global increases in SWA relative to age-matched controls that were most consistent in bilateral prefrontal regions; however, MDD men showed no significant differences relative to age-matched controls. Further analyses demonstrated increased SWA in MDD women was most prominent in the first portion of the night. Women, but not men with MDD demonstrate significant increases in SWA in multiple cortical areas relative to control subjects. Further research is warranted to investigate the role of SWA in MDD, and to clarify how increased SWA in women with MDD is related to the pathophysiology of the disorder.

Age, sex, and gonadal hormones differently influence anxiety- and depression-related behavior during puberty in mice.

PubMed

Boivin, Josiah R; Piekarski, David J; Wahlberg, Jessica K; Wilbrecht, Linda

2017-11-01

Anxiety and depression symptoms increase dramatically during adolescence, with girls showing a steeper increase than boys after puberty onset. The timing of the onset of this sex bias led us to hypothesize that ovarian hormones contribute to depression and anxiety during puberty. In humans, it is difficult to disentangle direct effects of gonadal hormones from social and environmental factors that interact with pubertal development to influence mental health. To test the role of gonadal hormones in anxiety- and depression-related behavior during puberty, we manipulated gonadal hormones in mice while controlling social and environmental factors. Similar to humans, we find that mice show an increase in depression-related behavior from pre-pubertal to late-pubertal ages, but this increase is not dependent on gonadal hormones and does not differ between sexes. Anxiety-related behavior, however, is more complex during puberty, with differences that depend on sex, age, behavioral test, and hormonal status. Briefly, males castrated before puberty show greater anxiety-related behavior during late puberty compared to intact males, while pubertal females are unaffected by ovariectomy or hormone injections in all assays except the marble burying test. Despite this sex-specific effect of pubertal hormones on anxiety-related behavior, we find no sex differences in intact young adults, suggesting that males and females use separate mechanisms to converge on a similar behavioral phenotype. Our results are consistent with anxiolytic effects of testicular hormones during puberty in males but are not consistent with a causal role for ovarian hormones in increasing anxiety- and depression-related behavior during puberty in females. Copyright © 2017 Elsevier Ltd. All rights reserved.

Sex Differences in Regional Brain Glucose Metabolism Following Opioid Withdrawal and Replacement.

PubMed

Santoro, Giovanni C; Carrion, Joseph; Patel, Krishna; Vilchez, Crystal; Veith, Jennifer; Brodie, Jonathan D; Dewey, Stephen L

2017-08-01

Methadone and buprenorphine are currently the most common pharmacological treatments for opioid dependence. Interestingly, the clinical response to these drugs appears to be sex specific. That is, females exhibit superior therapeutic efficacy, defined as extended periods of abstinence and longer time to relapse, compared with males. However, the underlying metabolic effects of opioid withdrawal and replacement have not been examined. Therefore, using 18 FDG and microPET, we measured differences in regional brain glucose metabolism in males and females following morphine withdrawal and subsequent methadone or buprenorphine replacement. In both males and females, spontaneous opioid withdrawal altered glucose metabolism in regions associated with reward and drug dependence. Specifically, metabolic increases in the thalamus, as well as metabolic decreases in insular cortex and the periaqueductal gray, were noted. However, compared with males, females exhibited increased metabolism in the preoptic area, primary motor cortex, and the amygdala, and decreased metabolism in the caudate/putamen and medial geniculate nucleus. Methadone and buprenorphine initially abolished these changes uniformly, but subsequently produced their own regional metabolic alterations that varied by treatment and sex. Compared with sex-matched control animals undergoing spontaneous opioid withdrawal, male animals treated with methadone exhibited increased caudate/putamen metabolism, whereas buprenorphine produced increased ventral striatum and motor cortex metabolism in females, and increased ventral striatum and somatosensory cortex metabolism in males. Notably, when treatment effects were compared between sexes, methadone-treated females showed increased cingulate cortex metabolism, whereas buprenorphine-treated females showed decreased metabolism in cingulate cortex and increased metabolism in the globus pallidus. Perhaps the initial similarities in males and females underlie early therapeutic efficacy, whereas these posttreatment sex differences contribute to clinical treatment failure more commonly experienced by the former.

Disability Estimates between Same- and Different-Sex Couples: Microdata from the American Community Survey (2009–2011)

PubMed Central

2014-01-01

Disability and sexual orientation have been used by some to unjustly discriminate against differently-abled and differently-oriented minority groups. Because little is known about the disability rates of individuals in same-sex unions, this technical report presents disability rates by separating couples into: same-sex-female; same-sex-male; different-sex-married; and different-sex-unmarried couples. Data from the American Community Survey (ACS) Public Use Microdata Sample (PUMS) 2009–2011 3-year file is utilized to produce estimates (and their standard errors) for the following six disability items: independent living; ambulatory; self-care; cognitive; hearing; and vision. Estimates of disability by selected geographies—i.e., Public Use Microdata Areas (PUMAs)—are also presented as is a figure showing a PUMA polygon. Qualitative comparisons seem to indicate that: same-sex-female couples have higher rates of disability compared to the other three groups; that in general, disability estimates for individuals in same-sex couples have a greater degree of uncertainty; and that disability-item-allocations are most prevalent in same-sex couples. Because societal marginalization may increase through cumulative processes, public health professionals should continue to seek out ways to identify underserved populations. PMID:25745275

Sex- and age-related variations of the somatotype in a Chuvasha population.

PubMed

Kalichman, L; Kobyliansky, E

2006-01-01

The aim of this large, cross-sectional study was to describe the age- and sex-related variations of the somatotype, employing Heath and Carter's method, in a Chuvasha population residing in a rural region in central Russia. The investigated sample included 802 males aged 18-89 years (mean 46.9) and 738 females aged 18-90 years (mean 48.6). We evaluated the age and sex differences by one-way ANOVA with somatotype components as dependent variables and sex or age groups as grouping variables. Sex differences of somatotypes appear to be the strongest for endomorphy, with generally higher values in women. Endomorphy in males remained virtually unchanged after 30 years of age, but endomorphy in females kept increasing up to the 6th decade, and then subsequently decreased. Virtually no differences were noted in mesomorphy and a very small difference in ectomorphy between males and females aged 18-30 years. A reduction of sexual dimorphism in all somatotype components after age 70 was also observed. The largest difference of all somatotype components appeared between age groups 18-30 and 31-40 years. Thereafter, somatotypes remained practically unchanged. Mesomorphy continued to increase until the 5th decade in both sexes, while in females, endomorphy continuously increased until their 6th decade. In the 7th and 8th decades, a decrease in mean values was observed. Mesomorphy and ectomorphy showed opposite age-related trends. Results of our study clearly suggest that in physique investigations, the somatotypes need to be studied in each sex separately, and in studies of young people, they need also to be adjusted to age.

Problems and Progress regarding Sex Bias and Omission in Neuroscience Research

PubMed Central

Will, Tyler R.; Proaño, Stephanie B.; Thomas, Anly M.; Kunz, Lindsey M.; Thompson, Kelly C.; Ginnari, Laura A.; Jones, Clay H.; Lucas, Sarah-Catherine; Reavis, Elizabeth M.

2017-01-01

Neuroscience research has historically ignored female animals. This neglect comes in two general forms. The first is sex bias, defined as favoring one sex over another; in this case, male over female. The second is sex omission, which is the lack of reporting sex. The recognition of this phenomenon has generated fierce debate across the sciences. Here we test whether sex bias and omission are still present in the neuroscience literature, whether studies employing both males and females neglect sex as an experimental variable, and whether sex bias and omission differs between animal models and journals. To accomplish this, we analyzed the largest-ever number of neuroscience articles for sex bias and omission: 6636 articles using mice or rats in 6 journals published from 2010 to 2014. Sex omission is declining, as increasing numbers of articles report sex. Sex bias remains present, as increasing numbers of articles report the sole use of males. Articles using both males and females are also increasing, but few report assessing sex as an experimental variable. Sex bias and omission varies substantially by animal model and journal. These findings are essential for understanding the complex status of sex bias and omission in neuroscience research and may inform effective decisions regarding policy action. PMID:29134192

Sex-Specific Differences in Shoaling Affect Parasite Transmission in Guppies

PubMed Central

Richards, E. Loys; van Oosterhout, Cock; Cable, Joanne

2010-01-01

Background Individuals have to trade-off the costs and benefits of group membership during shoaling behaviour. Shoaling can increase the risk of parasite transmission, but this cost has rarely been quantified experimentally. Guppies (Poecilia reticulata) are a model system for behavioural studies, and they are commonly infected by gyrodactylid parasites, notorious fish pathogens that are directly transmitted between guppy hosts. Methodology/Principal Findings Parasite transmission in single sex shoals of male and female guppies were observed using an experimental infection of Gyrodactylus turnbulli. Parasite transmission was affected by sex-specific differences in host behaviour, and significantly more parasites were transmitted when fish had more frequent and more prolonged contact with each other. Females shoaled significantly more than males and had a four times higher risk to contract an infection. Conclusions/Significance Intersexual differences in host behaviours such as shoaling are driven by differences in natural and sexual selection experienced by both sexes. Here we show that the potential benefits of an increased shoaling tendency are traded off against increased risks of contracting an infectious parasite in a group-living species. PMID:20949014

Sex differences in NSAID-induced perturbation of human intestinal barrier function and microbiota.

PubMed

Edogawa, Shoko; Peters, Stephanie A; Jenkins, Gregory D; Gurunathan, Sakteesh V; Sundt, Wendy J; Johnson, Stephen; Lennon, Ryan J; Dyer, Roy B; Camilleri, Michael; Kashyap, Purna C; Farrugia, Gianrico; Chen, Jun; Singh, Ravinder J; Grover, Madhusudan

2018-06-13

Intestinal barrier function and microbiota are integrally related and play critical roles in maintenance of host physiology. Sex is a key biologic variable for several disorders. Our aim was to determine sex-based differences in response to perturbation and subsequent recovery of intestinal barrier function and microbiota in healthy humans. Twenty-three volunteers underwent duodenal biopsies, mucosal impedance, and in vivo permeability measurement. Permeability testing was repeated after administration of indomethacin, then 4 to 6 wk after its discontinuation. Duodenal and fecal microbiota composition was determined using 16S rRNA amplicon sequencing. Healthy women had lower intestinal permeability and higher duodenal and fecal microbial diversity than healthy men. Intestinal permeability increases after indomethacin administration in both sexes. However, only women demonstrated decreased fecal microbial diversity, including an increase in Prevotella abundance, after indomethacin administration. Duodenal microbiota composition did not show sex-specific changes. The increase in permeability and microbiota changes normalized after discontinuation of indomethacin. In summary, women have lower intestinal permeability and higher microbial diversity. Intestinal permeability is sensitive to perturbation but recovers to baseline. Gut microbiota in women is sensitive to perturbation but appears to be more stable in men. Sex-based differences in intestinal barrier function and microbiome should be considered in future studies.-Edogawa, S., Peters, S. A., Jenkins, G. D., Gurunathan, S. V., Sundt, W. J., Johnson, S., Lennon, R. J., Dyer, R. B., Camilleri, M., Kashyap, P. C., Farrugia, G., Chen, J., Singh, R. J., Grover, M. Sex differences in NSAID-induced perturbation of human intestinal barrier function and microbiota.

Cell-autonomous sex determination outside of the gonad

PubMed Central

Arnold, Arthur P.; Chen, Xuqi; Link, Jenny C.; Itoh, Yuichiro; Reue, Karen

2013-01-01

The classic model of sex determination in mammals states that the sex of the individual is determined by the type of gonad that develops, which in turn determines the gonadal hormonal milieu that creates sex differences outside of the gonads. However, XX and XY cells are intrinsically different because of the cell-autonomous sex-biasing action of X and Y genes. Recent studies of mice, in which sex chromosome complement is independent of gonadal sex, reveal that sex chromosome complement has strong effects contributing to sex differences in phenotypes such as metabolism. Adult mice with two X chromosomes (relative to mice with one X chromosome) show dramatically greater increases in body weight and adiposity after gonadectomy, irrespective of their gonadal sex. When fed a high fat diet, XX mice develop striking hyperinsulinemia and fatty liver, relative to XY mice. The sex chromosome effects are modulated by the presence of gonadal hormones, indicating an interaction of the sex-biasing effects of gonadal hormones and sex chromosome genes. Other cell-autonomous sex chromosome effects are detected in mice in many phenotypes. Birds (relative to eutherian mammals) are expected to show more widespread cell-autonomous sex determination in non-gonadal tissues, because of ineffective sex chromosome dosage compensation mechanisms. PMID:23361913

Eye tracking, strategies, and sex differences in virtual navigation.

PubMed

Andersen, Nicolas E; Dahmani, Louisa; Konishi, Kyoko; Bohbot, Véronique D

2012-01-01

Reports of sex differences in wayfinding have typically used paradigms sensitive to the female advantage (navigation by landmarks) or sensitive to the male advantage (navigation by cardinal directions, Euclidian coordinates, environmental geometry, and absolute distances). The current virtual navigation paradigm allowed both men and women an equal advantage. We studied sex differences by systematically varying the number of landmarks. Eye tracking was used to quantify sex differences in landmark utilisation as participants solved an eight-arm radial maze task within different virtual environments. To solve the task, participants were required to remember the locations of target objects within environments containing 0, 2, 4, 6, or 8 landmarks. We found that, as the number of landmarks available in the environment increases, the proportion of time men and women spend looking at landmarks and the number of landmarks they use to find their way increases. Eye tracking confirmed that women rely more on landmarks to navigate, although landmark fixations were also associated with an increase in task completion time. Sex differences in navigational behaviour occurred only in environments devoid of landmarks and disappeared in environments containing multiple landmarks. Moreover, women showed sustained landmark-oriented gaze, while men's decreased over time. Finally, we found that men and women use spatial and response strategies to the same extent. Together, these results shed new light on the discrepancy in landmark utilisation between men and women and help explain the differences in navigational behaviour previously reported. Copyright © 2011 Elsevier Inc. All rights reserved.

Sex Ideologies in China: Examining Interprovince Differences.

PubMed

Hu, Yang

2016-01-01

In recent decades, premarital sex, extramarital sex, and homosexuality have become increasingly visible in China, leading scholars to claim that a national "sex revolution" is under way. However, China's internal sociocultural diversity calls this nation-level generalization into question. How do sex ideologies vary across China's distinct provinces? To what extent are interprovince variations in sex ideologies associated with distinct macrolevel social factors in China? In this research, data from the 2010 China General Social Survey and the 2011 Chinese Statistics Yearbook were analyzed using multilevel models to test four contending theories of interprovince differences in sex ideologies in China: modernization, Westernization, deindustrialization, and the "rice theory." The modernization theory was unsupported by the results, as socioeconomic development is not significantly associated with sex ideologies. Higher levels of deindustrialization and Westernization were associated with less traditional sex ideologies, but the strength of association varied across the domains of premarital sex, extramarital sex, and homosexuality. The rice theory was consistently supported, as the distinction between rice and wheat agriculture explained up to 30% of the province-level variance in sex ideologies. The findings underline the roles of both long-standing geographic differences and recent social changes in shaping China's ideational landscape of sex.

In Search of Emerging Same-Sex Sexuality: Romantic Attractions at Age 13 Years.

PubMed

Li, Gu; Hines, Melissa

2016-10-01

Sex-typed behavior in childhood is significantly related to sexual orientation in adulthood. In addition, same-sex attractions in early adolescence are more non-exclusive than in adulthood and can differ from later same-sex orientations. However, little research has focused on romantic attractions as they emerge during early adolescence. Drawing a sample from the Avon Longitudinal Study of Parents and Children (197 girls, 204 boys), the current study examined whether same-sex romantic attractions at age 13 years were exclusive, and whether they were predicted by sex-typed behavior at age 3.5 years. No young adolescents in this sample reported exclusive same-sex attractions, and increased same-sex attractions were not significantly related to reduced other-sex sexualities. Childhood sex-typed behavior did not significantly predict early same-sex attractions, suggesting that early same-sex attractions differ from later same-sex orientations. The current study highlights the importance of studying the development of sexuality beginning prior to adulthood.

An fMRI study of sex differences in regional activation to a verbal and a spatial task.

PubMed

Gur, R C; Alsop, D; Glahn, D; Petty, R; Swanson, C L; Maldjian, J A; Turetsky, B I; Detre, J A; Gee, J; Gur, R E

2000-09-01

Sex differences in cognitive performance have been documented, women performing better on some phonological tasks and men on spatial tasks. An earlier fMRI study suggested sex differences in distributed brain activation during phonological processing, with bilateral activation seen in women while men showed primarily left-lateralized activation. This blood oxygen level-dependent fMRI study examined sex differences (14 men, 13 women) in activation for a spatial task (judgment of line orientation) compared to a verbal-reasoning task (analogies) that does not typically show sex differences. Task difficulty was manipulated. Hypothesized ROI-based analysis documented the expected left-lateralized changes for the verbal task in the inferior parietal and planum temporal regions in both men and women, but only men showed right-lateralized increase for the spatial task in these regions. Image-based analysis revealed a distributed network of cortical regions activated by the tasks, which consisted of the lateral frontal, medial frontal, mid-temporal, occipitoparietal, and occipital regions. The activation was more left lateralized for the verbal and more right for the spatial tasks, but men also showed some left activation for the spatial task, which was not seen in women. Increased task difficulty produced more distributed activation for the verbal and more circumscribed activation for the spatial task. The results suggest that failure to activate the appropriate hemisphere in regions directly involved in task performance may explain certain sex differences in performance. They also extend, for a spatial task, the principle that bilateral activation in a distributed cognitive system underlies sex differences in performance. Copyright 2000 Academic Press.

The new science of cognitive sex differences.

PubMed

Miller, David I; Halpern, Diane F

2014-01-01

Surprising new findings indicate that many conclusions about sex differences and similarities in cognitive abilities need to be reexamined. Cognitive sex differences are changing, decreasing for some tasks whereas remaining stable or increasing for other tasks. Some sex differences are detected in infancy, but the data are complex and depend on task characteristics. Diverse disciplines have revolutionized our understanding of why these differences exist. For instance, fraternal-twin studies align with earlier literature to help establish the role of prenatal androgens and large international datasets help explain how cultural factors such as economic prosperity and gender equity affect females and males differently. Understanding how biological and environmental factors interact could help maximize cognitive potential and address pressing societal issues. Copyright © 2013 Elsevier Ltd. All rights reserved.

[Gender: new methodological approaches in guideline development].

PubMed

Weinbrenner, Susanne; Lönnfors, Sanna; Babitsch, Birgit

2010-01-01

Gender and diversity have a strong impact on health and illness as evidenced by sex and gender differences in the onset and progression of diseases as well as in diagnosis, therapy, and therapeutic outcome. The number of sex/gender-specific studies in medicine has increased steadily in recent years, indicating sex (biological) and gender (social) differences in numerous diseases. Despite this evidence, however, sex/gender differences are rarely considered in medical practice or in health systems, suggesting a delay in transferring such research into evidence-based medical treatment. Similarly, quality improvement guidelines in medical care do not systematically integrate the sex/gender perspective. Against this backdrop, this paper seeks to enumerate the necessary components of a guideline development and evaluation process that systematically integrates sex/gender differences in addition to providing a sex/gender-based methodological approach. The latter is illustrated by a pilot study in which four international guidelines on depression were selected. The sex/gender appropriateness of these guidelines was analysed using two methods: first, sex/gender-relevant words were counted; and second, relevant sex/gender differences were summarised based on a systematic literature review and then compared with the information given in the guidelines. The findings of the pilot study revealed that although strong evidence exists on sex/gender differences in depression, such research was rarely implemented in the guidelines. Given the scope and potential of guidelines to improve the quality of health care, it is essential that they consider the crucial role of sex/gender differences. To date, sex/gender differences have been insufficiently addressed in guideline development and evaluation when they should be an integral component of the process. Copyright © 2010. Published by Elsevier GmbH.

Deletion of Fmr1 results in sex-specific changes in behavior.

PubMed

Nolan, Suzanne O; Reynolds, Conner D; Smith, Gregory D; Holley, Andrew J; Escobar, Brianna; Chandler, Matthew A; Volquardsen, Megan; Jefferson, Taylor; Pandian, Ashvini; Smith, Tileena; Huebschman, Jessica; Lugo, Joaquin N

2017-10-01

In this study, we used a systemic Fmr1 knockout in order to investigate both genotype- and sex-specific differences across multiple measures of sociability, repetitive behaviors, activity levels, anxiety, and fear-related learning and memory. Fragile X syndrome is the most common monogenic cause of intellectual disability and autism. Few studies to date have examined sex differences in a mouse model of Fragile X syndrome, though clinical data support the idea of differences in both overall prevalence and phenotype between the sexes. Using wild-type and systemic homozygous Fmr1 knockout mice, we assessed a variety of behavioral paradigms in adult animals, including the open field test, elevated plus maze, nose-poke assay, accelerating rotarod, social partition task, three-chambered social task, and two different fear conditioning paradigms. Tests were ordered such that the most invasive tests were performed last in the sequence, and testing paradigms for similar behaviors were performed in separate cohorts to minimize testing effects. Our results indicate several sex-specific changes in Fmr1 knockout mice, including male-specific increases in activity levels, and female-specific increases in repetitive behaviors on both the nose-poke assay and motor coordination on the accelerating rotarod task. The results also indicated that Fmr1 deletion results in deficits in fear learning and memory across both sexes, and no changes in social behavior across two tasks. These findings highlight the importance of including female subjects in preclinical studies, as simply studying the impact of genetic mutations in males does not yield a complete picture of the phenotype. Further research should explore these marked phenotypic differences among the sexes. Moreover, given that treatment strategies are typically equivalent between the sexes, the results highlight a potential need for sex-specific therapeutics.

Sex differences in parental care: Gametic investment, sexual selection, and social environment.

PubMed

Liker, András; Freckleton, Robert P; Remeš, Vladimir; Székely, Tamás

2015-11-01

Male and female parents often provide different type and amount of care to their offspring. Three major drivers have been proposed to explain parental sex roles: (1) differential gametic investment by males and females that precipitates into sex difference in care, (2) different intensity of sexual selection acting on males and females, and (3) biased social environment that facilitates the more common sex to provide more care. Here, we provide the most comprehensive assessment of these hypotheses using detailed parental care data from 792 bird species covering 126 families. We found no evidence for the gametic investment hypothesis: neither gamete sizes nor gamete production by males relative to females was related to sex difference in parental care. However, sexual selection correlated with parental sex roles, because the male share in care relative to female decreased with both extra-pair paternity and frequency of male polygamy. Parental sex roles were also related to social environment, because male parental care increased with male-biased adult sex ratios (ASRs). Taken together, our results are consistent with recent theories suggesting that gametic investment is not tied to parental sex roles, and highlight the importance of both sexual selection and ASR in influencing parental sex roles. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

Dual use of alcohol and marijuana and condomless sex in young adult men and women: A within-subject day-level analysis.

PubMed

Hayaki, Jumi; Anderson, Bradley J; Stein, Michael D

2018-06-20

Unprotected sex has been linked independently to alcohol and marijuana use, but few studies have examined associations with dual use or gender differences in these associations. This study examined day-level associations between unprotected sex, defined as condomless vaginal sex with an opposite-sex partner, and use of alcohol, marijuana, neither, or both substances among 290 young adults (18-25 years, 52.3% female) who reported either alcohol or marijuana use. Participants reported demographics, alcohol use, marijuana use, and at least one episode of condomless sex as defined above in the past 90 days (Timeline Follow-Back). The likelihood of condomless sex was examined for days when alcohol, marijuana, neither, or both were used. Gender differences were also explored. For females, compared to days with no substance use, the estimated risk of condomless sex increased by a factor of 2.12 on alcohol use days, 1.89 on marijuana use days, and 3.39 on dual use days. Among males, the odds of condomless sex increased only slightly on alcohol use (odds ratio [OR] = 1.03) or marijuana use (OR = 1.08) days, but increased by a factor of 1.71 on dual use days. Young persons who use alcohol and/or marijuana experience heightened likelihood of condomless sex. This increased likelihood is greater for women than for men on days with alcohol or marijuana use, each alone but especially when combined. Young women may be especially susceptible to the influence of alcohol and/or marijuana use on sexual behavior. (Am J Addict 2018;XX:1-6). © 2018 American Academy of Addiction Psychiatry.

Sex differences in chronic stress responses and Alzheimer's disease.

PubMed

Yan, Yan; Dominguez, Sky; Fisher, Daniel W; Dong, Hongxin

2018-02-01

Clinical studies indicate that Alzheimer's disease (AD) disproportionately affects women in both disease prevalence and severity, but the mechanisms underlying this sex divergence are unknown. Though some have suggested this difference in risk is a reflection of known differences in longevity between men and women, mounting clinical and preclinical evidence supports women also having intrinsic susceptibilities towards the disease. While a number of potential risk factors have been hypothesized to affect these differences in risks, none have been definitively verified. In this review, we discuss a novel hypothesis whereby women's susceptibility to chronic stress also mediates increased risk for AD. As stress is a risk factor for AD, and women are twice as likely to develop mood disorders where stress is a major etiology, it is possible that sex dimorphisms in stress responses contribute to the increase in women with AD. In line with this, sex divergence in biochemical responses to stress have been noted along the hypothalamic-pituitary-adrenal (HPA) axis and among known molecular effectors of AD, with crosstalk between these processes also being likely. In addition, activation of the cortical corticotrophin-releasing factor receptor 1 (CRF1) signaling pathway leads to distinct female-biased increases in molecules associated with AD pathogenesis. Therefore, the different biochemical responses to stress between women and men may represent an intrinsic, sex-dependent risk factor for AD.

Adolescent neural response to reward is related to participant sex and task motivation

PubMed Central

Alarcón, Gabriela; Cservenka, Anita; Nagel, Bonnie J.

2017-01-01

Risky decision making is prominent during adolescence, perhaps contributed to by heightened sensation seeking and ongoing maturation of reward and dopamine systems in the brain, which are, in part, modulated by sex hormones. In this study, we examined sex differences in the neural substrates of reward sensitivity during a risky decision-making task and hypothesized that compared with girls, boys would show heightened brain activation in reward-relevant regions, particularly the nucleus accumbens, during reward receipt. Further, we hypothesized that testosterone and estradiol levels would mediate this sex difference. Moreover, we predicted boys would make more risky choices on the task. While boys showed increased nucleus accumbens blood oxygen level-dependent (BOLD) response relative to girls, sex hormones did not mediate this effect. As predicted, boys made a higher percentage of risky decisions during the task. Interestingly, boys also self-reported more motivation to perform well and earn money on the task, while girls self-reported higher state anxiety prior to the scan session. Motivation to earn money partially mediated the effect of sex on nucleus accumbens activity during reward. Previous research shows that increased motivation and salience of reinforcers is linked with more robust striatal BOLD response, therefore psychosocial factors, in addition to sex, may play an important role in reward sensitivity. Elucidating neurobiological mechanisms that support adolescent sex differences in risky decision making has important implications for understanding individual differences that lead to advantageous and adverse behaviors that affect health outcomes. PMID:27816780

Variable mycorrhizal benefits on the reproductive output of Geranium sylvaticum, with special emphasis on the intermediate phenotype.

PubMed

Varga, S; Kytöviita, M-M

2014-03-01

In several gynodioecious species, intermediate sex between female and hermaphrodite has been reported, but few studies have investigated fitness parameters of this intermediate phenotype. Here, we examined the interactions between plant sex and arbuscular mycorrhizal (AM) fungal species affecting the reproductive output of Geranium sylvaticum, a sexually polymorphic plant species with frequent intermediate sexes between females and hermaphrodites, using a common garden experiment. Flowering phenology, AM colonisation levels and several plant vegetative and reproductive parameters, including seed and pollen production, were measured. Differences among sexes were detected in flowering, fruit set, pollen production and floral size. The two AM species used in the present work had different effects on plant fitness parameters. One AM species increased female fitness through increasing seed number and seed mass, while the other species reduced seed mass in all sexes investigated. AM fungi did not affect intermediate and hermaphrodite pollen content in anthers. The three sexes in G. sylvaticum did not differ in their reproductive output in terms of total seed production, but hermaphrodites had potentially larger fathering ability than intermediates due to higher anther number. The ultimate female function--seed production--did not differ among the sexes, but one of the AM fungi used potentially decreased host plant fitness. In addition, in the intermediate sex, mycorrhizal symbiosis functioned similarly in females as in hermaphrodites. © 2013 German Botanical Society and The Royal Botanical Society of the Netherlands.

Sex Differences in Proximal Control of the Knee Joint

PubMed Central

Mendiguchia, Jurdan; Ford, Kevin R.; Quatman, Carmen E.; Alentorn-Geli, Eduard; Hewett, Timothy E.

2014-01-01

Following the onset of maturation, female athletes have a significantly higher risk for anterior cruciate ligament (ACL) injury compared with male athletes. While multiple sex differences in lower-extremity neuromuscular control and biomechanics have been identified as potential risk factors for ACL injury in females, the majority of these studies have focused specifically on the knee joint. However, increasing evidence in the literature indicates that lumbopelvic (core) control may have a large effect on knee-joint control and injury risk. This review examines the published evidence on the contributions of the trunk and hip to knee-joint control. Specifically, the sex differences in potential proximal controllers of the knee as risk factors for ACL injury are identified and discussed. Sex differences in trunk and hip biomechanics have been identified in all planes of motion (sagittal, coronal and transverse). Essentially, female athletes show greater lateral trunk displacement, altered trunk and hip flexion angles, greater ranges of trunk motion, and increased hip adduction and internal rotation during sport manoeuvres, compared with their male counterparts. These differences may increase the risk of ACL injury among female athletes. Prevention programmes targeted towards trunk and hip neuromuscular control may decrease the risk for ACL injuries. PMID:21688868

Genetic Mechanisms Leading to Sex Differences Across Common Diseases and Anthropometric Traits.

PubMed

Traglia, Michela; Bseiso, Dina; Gusev, Alexander; Adviento, Brigid; Park, Daniel S; Mefford, Joel A; Zaitlen, Noah; Weiss, Lauren A

2017-02-01

Common diseases often show sex differences in prevalence, onset, symptomology, treatment, or prognosis. Although studies have been performed to evaluate sex differences at specific SNP associations, this work aims to comprehensively survey a number of complex heritable diseases and anthropometric traits. Potential genetically encoded sex differences we investigated include differential genetic liability thresholds or distributions, gene-sex interaction at autosomal loci, major contribution of the X-chromosome, or gene-environment interactions reflected in genes responsive to androgens or estrogens. Finally, we tested the overlap between sex-differential association with anthropometric traits and disease risk. We utilized complementary approaches of assessing GWAS association enrichment and SNP-based heritability estimation to explore explicit sex differences, as well as enrichment in sex-implicated functional categories. We do not find consistent increased genetic load in the lower-prevalence sex, or a disproportionate role for the X-chromosome in disease risk, despite sex-heterogeneity on the X for several traits. We find that all anthropometric traits show less than complete correlation between the genetic contribution to males and females, and find a convincing example of autosome-wide genome-sex interaction in multiple sclerosis (P = 1 × 10 -9 ). We also find some evidence for hormone-responsive gene enrichment, and striking evidence of the contribution of sex-differential anthropometric associations to common disease risk, implying that general mechanisms of sexual dimorphism determining secondary sex characteristics have shared effects on disease risk. Copyright © 2017 by the Genetics Society of America.

Genetic Mechanisms Leading to Sex Differences Across Common Diseases and Anthropometric Traits

PubMed Central

Traglia, Michela; Bseiso, Dina; Gusev, Alexander; Adviento, Brigid; Park, Daniel S.; Mefford, Joel A.; Zaitlen, Noah; Weiss, Lauren A.

2017-01-01

Common diseases often show sex differences in prevalence, onset, symptomology, treatment, or prognosis. Although studies have been performed to evaluate sex differences at specific SNP associations, this work aims to comprehensively survey a number of complex heritable diseases and anthropometric traits. Potential genetically encoded sex differences we investigated include differential genetic liability thresholds or distributions, gene–sex interaction at autosomal loci, major contribution of the X-chromosome, or gene–environment interactions reflected in genes responsive to androgens or estrogens. Finally, we tested the overlap between sex-differential association with anthropometric traits and disease risk. We utilized complementary approaches of assessing GWAS association enrichment and SNP-based heritability estimation to explore explicit sex differences, as well as enrichment in sex-implicated functional categories. We do not find consistent increased genetic load in the lower-prevalence sex, or a disproportionate role for the X-chromosome in disease risk, despite sex-heterogeneity on the X for several traits. We find that all anthropometric traits show less than complete correlation between the genetic contribution to males and females, and find a convincing example of autosome-wide genome-sex interaction in multiple sclerosis (P = 1 × 10−9). We also find some evidence for hormone-responsive gene enrichment, and striking evidence of the contribution of sex-differential anthropometric associations to common disease risk, implying that general mechanisms of sexual dimorphism determining secondary sex characteristics have shared effects on disease risk. PMID:27974502

Topographic and sex-related differences in sleep spindles in major depressive disorder: a high-density EEG investigation.

PubMed

Plante, D T; Goldstein, M R; Landsness, E C; Peterson, M J; Riedner, B A; Ferrarelli, F; Wanger, T; Guokas, J J; Tononi, G; Benca, R M

2013-03-20

Sleep spindles are believed to mediate several sleep-related functions including maintaining disconnection from the external environment during sleep, cortical development, and sleep-dependent memory consolidation. Prior studies that have examined sleep spindles in major depressive disorder (MDD) have not demonstrated consistent differences relative to control subjects, which may be due to sex-related variation and limited spatial resolution of spindle detection. Thus, this study sought to characterize sleep spindles in MDD using high-density electroencephalography (hdEEG) to examine the topography of sleep spindles across the cortex in MDD, as well as sex-related variation in spindle topography in the disorder. All-night hdEEG recordings were collected in 30 unipolar MDD participants (19 women) and 30 age and sex-matched controls. Topography of sleep spindle density, amplitude, duration, and integrated spindle activity (ISA) were assessed to determine group differences. Spindle parameters were compared between MDD and controls, including analysis stratified by sex. As a group, MDD subjects demonstrated significant increases in frontal and parietal spindle density and ISA compared to controls. When stratified by sex, MDD women demonstrated increases in frontal and parietal spindle density, amplitude, duration, and ISA; whereas MDD men demonstrated either no differences or decreases in spindle parameters. Given the number of male subjects, this study may be underpowered to detect differences in spindle parameters in male MDD participants. This study demonstrates topographic and sex-related differences in sleep spindles in MDD. Further research is warranted to investigate the role of sleep spindles and sex in the pathophysiology of MDD. Copyright © 2012 Elsevier B.V. All rights reserved.

IS THERE A VIABILITY-VULNERABILITY TRADEOFF? SEX DIFFERENCES IN FETAL PROGRAMMING

PubMed Central

SANDMAN, CURT A; GLYNN, LAURA M; DAVIS, ELYSIA POGGI

2013-01-01

OBJECTIVE In this paper we evaluate the evidence for sex differences in fetal programming within the context of the proposed viability-vulnerability tradeoff. METHODS We briefly review the literature on the factors contributing to primary and secondary sex ratios. Sex differences in fetal programming are assessed by summarizing previously published sex difference findings from our group (6 studies) and also new analyses of previously published findings in which sex differences were not reported (6 studies). RESULTS The review and reanalysis of studies from our group are consistent with the overwhelming evidence of increasing risk for viability among males exposed to environmental adversity early in life. New evidence reported here support the argument that females, despite their adaptive agility, also are influenced by exposure to early adversity. Two primary conclusions are (i) female fetal exposure to psychobiological stress selectively influences fear/anxiety, and (ii) the effects of female fetal exposure to stress persist into preadolescence. These persisting effects are reflected in increased levels of anxiety, impaired executive function and neurological markers associated with these behaviors. CONCLUSIONS A tacit assumption is that females, with their adaptive flexibility early in gestation, escape the consequences of early life exposure to adversity. We argue that the consequences of male exposure to early adversity threatens their viability, effectively culling the weak and the frail and creating a surviving cohort of the fittest. Females adjust to early adversity with a variety of strategies, but their escape from the risk of early mortality and morbidity has a price of increased vulnerability expressed later in development. PMID:24119938

To Stroop or Not to Stroop: Sex-Related Differences in Brain-Behavior Associations During Early Childhood

PubMed Central

Cuevas, Kimberly; Calkins, Susan D.; Bell, Martha Ann

2015-01-01

Executive functions (EFs) are linked with optimal cognitive and social-emotional development. Despite behavioral evidence of sex differences in early childhood EF, little is known about potential sex differences in corresponding brain-behavior associations. The present study examined changes in 4-year-olds’ 6–9 Hz EEG power in response to increased executive processing demands (i.e., “Stroop-like” vs. “non-Stroop” day-night tasks). Although there were no sex differences in task performance, an examination of multiple scalp electrode sites revealed that boys exhibited more widespread changes in EEG power as compared to girls. Further, multiple regression analyses controlling for maternal education and non-EF performance indicated that individual differences in boys’ and girls’ EF performance were associated with different frontal neural correlates (i.e., different frontal scalp sites and different measures of EEG power). These data reveal valuable information concerning sex differences in the neural systems underlying executive processing during early childhood. PMID:26681615

The Impact of Single-Sex Education on Male and Female Gains in Mathematics and Reading at the Elementary Level in a Selected School in North Carolina

ERIC Educational Resources Information Center

O'Neill, Lisa

2011-01-01

The gender gap in achievement and the increasing awareness of differences between male and female cognitive development have ignited a growing interest in single-sex education. No Child Left Behind legislation and amendments to Title IX legislation have increased the number of schools in America offering single-sex education. This 2-year…

Role of corticosteroid binding globulin in emotional reactivity sex differences in mice.

PubMed

Minni, A M; de Medeiros, G F; Helbling, J C; Duittoz, A; Marissal-Arvy, N; Foury, A; De Smedt-Peyrusse, V; Pallet, V; Moisan, M P

2014-12-01

Sex differences exist for stress reactivity as well as for the prevalence of depression, which is more frequent in women of reproductive age and often precipitated by stressful events. In animals, the differential effect of stress on male's and female's emotional behavior has been well documented. Crosstalk between the gonadal and stress hormones, in particular between estrogens and glucocorticoids, underlie these sex differences on stress vulnerability. We have previously shown that corticosteroid binding globulin (CBG) deficiency in a mouse model (Cbg k.o.) leads, in males, to an increased despair-like behavior caused by suboptimal corticosterone stress response. Because CBG displays a sexual dimorphism and is regulated by estrogens, we have now investigated whether it plays a role in the sex differences observed for emotional reactivity in mice. By analyzing Cbg k.o. and wild-type (WT) animals of both sexes, we detected sex differences in despair-like behavior in WT mice but not in Cbg k.o. animals. We showed through ovariectomy and estradiol (E2) replacement that E2 levels explain the sex differences found in WT animals. However, the manipulation of E2 levels did not affect the emotional behavior of Cbg k.o. females. As Cbg k.o. males, Cbg k.o. females have markedly reduced corticosterone levels across the circadian cycle and also after stress. Plasma free corticosterone levels in Cbg k.o. mice measured immediately after stress were blunted in both sexes compared to WT mice. A trend for higher mean levels of ACTH in Cbg k.o. mice was found for both sexes. The turnover of a corticosterone bolus was increased in Cbg k.o. Finally, the glucocorticoid-regulated immediate early gene early growth response 1 (Egr1) showed a blunted mRNA expression in the hippocampus of Cbg k.o. mutants while mineralocorticoid and glucocorticoid receptors presented sex differences but equivalent mRNA expression between genotypes. Thus, in our experimental conditions, sex differences for despair-like behavior in WT mice are explained by estrogens levels. Also, in both sexes, the presence of CBG is required to attain optimal glucocorticoid concentrations and normal emotional reactivity, although in females this is apparent only under low E2 concentrations. These findings suggest a complex interaction of CBG and E2 on emotional reactivity in females. Copyright © 2014 Elsevier Ltd. All rights reserved.

Substance Use and the Development of Sexual Risk Behaviors in Youth Perinatally Exposed to HIV

PubMed Central

Bauermeister, José A.; Santamaria, E. Karina; Dolezal, Curtis; Mellins, Claude A.

2015-01-01

Objective To examine the longitudinal association between sexual behavior and substance use in perinatally HIV-infected (PHIV+) and perinatally HIV-exposed-but-uninfected (PHIV−) youth. Methods Growth curve modeling was used with data from N = 340 PHIV-exposed youth (60.6% PHIV+; 9–22 years) to estimate the onset of penetrative and unprotected sex across time, adding alcohol and marijuana use trajectories as time-varying covariates and examining HIV-status differences. Results The odds of penetrative or unprotected sex more than doubled across time. Alcohol and marijuana use significantly increased the odds of engaging in sex and unprotected sex, with no HIV-status differences. The association between unprotected sex and alcohol use was less salient for PHIV+ than PHIV− youth. Conclusions Similar to youth from other populations, PHIV+ and PHIV− youth are increasingly engaging in sex and substance use as they age. Targeted interventions to prevent sexual risk behavior and further HIV transmission should address the influence of substance use. PMID:25476800

Human males appear more prepared than females to resolve conflicts with same-sex peers.

PubMed

Benenson, Joyce F; Kuhn, Melissa N; Ryan, Patrick J; Ferranti, Anthony J; Blondin, Rose; Shea, Michael; Charpentier, Chalice; Thompson, Melissa Emery; Wrangham, Richard W

2014-06-01

The aim of the study was to investigate sex differences in proximate mechanisms that precede the termination of conflicts. In Study 1, we asked women and men to report their intensity of anger in response to hypothetical, common transgressions involving a same-sex roommate. Direct verbal and physical aggression elicited the highest-intensity anger for both sexes, although overall women reported more intense anger than men to all transgressions. In Study 2, we examined sex differences in subjective and physiological reactions to a conflict using a role-playing scenario. Following recall of a conflict involving direct aggression and role-playing a reaction to it, compared with men, women reported their anger would dissipate less quickly and they would take longer to reconcile. Women also exhibited increased heart rate, but little change in cortisol, whereas men exhibited little change in heart rate but increased cortisol production. We interpret the results as indicating that women are less prepared than men to resolve a conflict with a same-sex peer.

Differences by Sex in Association of Mental Health With Video Gaming or Other Nonacademic Computer Use Among US Adolescents

PubMed Central

Sung, Jung Hye; Lee, Ji-Young; Lee, Jae Eun

2017-01-01

Introduction Although numerous studies have examined the association between playing video games and cognitive skills, aggression, and depression, few studies have examined how these associations differ by sex. The objective of our study was to determine differences by sex in association between video gaming or other nonacademic computer use and depressive symptoms, suicidal behavior, and being bullied among adolescents in the United States. Methods We used data from the 2015 Youth Risk Behavior Survey on 15,624 US high school students. Rao–Scott χ2 tests, which were adjusted for the complex sampling design, were conducted to assess differences by sex in the association of mental health with video gaming or other nonacademic computer use. Results Approximately one-fifth (19.4%) of adolescents spent 5 or more hours daily on video gaming or other nonacademic computer use, and 17.9% did not spend any time in those activities. A greater percentage of female adolescents than male adolescents reported spending no time (22.1% and 14.0%, respectively) or 5 hours or more (21.3% and 17.5%, respectively) in gaming and other nonacademic computer use (P < .001). The association between mental problems and video gaming or other nonacademic computer use differed by sex. Among female adolescents, prevalence of mental problems increased steadily in association with increased time spent, whereas the pattern for male adolescents followed a J-shaped curve, decreasing initially, increasing slowly, and then increasing rapidly beginning at 4 hours or more. Conclusion Female adolescents were more likely to have all 3 mental health problems than male adolescents were. Spending no time or 5 hours or more daily on video gaming or other nonacademic computer use was associated with increased mental problems among both sexes. As suggested by the J-shaped relationship, 1 hour or less spent on video gaming or other nonacademic computer use may reduce depressive symptoms, suicidal behavior, and being bullied compared with no use or excessive use. PMID:29166250

Differences by Sex in Association of Mental Health With Video Gaming or Other Nonacademic Computer Use Among US Adolescents.

PubMed

Lee, Hogan H; Sung, Jung Hye; Lee, Ji-Young; Lee, Jae Eun

2017-11-22

Although numerous studies have examined the association between playing video games and cognitive skills, aggression, and depression, few studies have examined how these associations differ by sex. The objective of our study was to determine differences by sex in association between video gaming or other nonacademic computer use and depressive symptoms, suicidal behavior, and being bullied among adolescents in the United States. We used data from the 2015 Youth Risk Behavior Survey on 15,624 US high school students. Rao-Scott χ 2 tests, which were adjusted for the complex sampling design, were conducted to assess differences by sex in the association of mental health with video gaming or other nonacademic computer use. Approximately one-fifth (19.4%) of adolescents spent 5 or more hours daily on video gaming or other nonacademic computer use, and 17.9% did not spend any time in those activities. A greater percentage of female adolescents than male adolescents reported spending no time (22.1% and 14.0%, respectively) or 5 hours or more (21.3% and 17.5%, respectively) in gaming and other nonacademic computer use (P < .001). The association between mental problems and video gaming or other nonacademic computer use differed by sex. Among female adolescents, prevalence of mental problems increased steadily in association with increased time spent, whereas the pattern for male adolescents followed a J-shaped curve, decreasing initially, increasing slowly, and then increasing rapidly beginning at 4 hours or more. Female adolescents were more likely to have all 3 mental health problems than male adolescents were. Spending no time or 5 hours or more daily on video gaming or other nonacademic computer use was associated with increased mental problems among both sexes. As suggested by the J-shaped relationship, 1 hour or less spent on video gaming or other nonacademic computer use may reduce depressive symptoms, suicidal behavior, and being bullied compared with no use or excessive use.

The Emergence of Sex Differences in Personality Traits in Early Adolescence: A Cross-Sectional, Cross-Cultural Study

PubMed Central

De Bolle, Marleen; De Fruyt, Filip; McCrae, Robert R.; Löckenhoff, Corinna E.; Costa, Paul T.; Aguilar-Vafaie, Maria E.; Ahn, Chang-kyu; Ahn, Hyun-nie; Alcalay, Lidia; Allik, Jüri; Avdeyeva, Tatyana V.; Bratko, Denis; Brunner-Sciarra, Marina; Cain, Thomas R.; Chan, Wayne; Chittcharat, Niyada; Crawford, Jarret T.; Fehr, Ryan; Ficková, Emília; Gelfand, Michele J.; Graf, Sylvie; Gülgöz, Sami; Hřebíčková, Martina; Jussim, Lee; Klinkosz, Waldemar; Knežević, Goran; de Figueroa, Nora Leibovich; Lima, Margarida P.; Martin, Thomas A.; Marušić, Iris; Mastor, Khairul Anwar; Nakazato, Katsuharu; Nansubuga, Florence; Porrata, Jose; Purić, Danka; Realo, Anu; Reátegui, Norma; Rolland, Jean-Pierre; Schmidt, Vanina; Sekowski, Andrzej; Shakespeare-Finch, Jane; Shimonaka, Yoshiko; Simonetti, Franco; Siuta, Jerzy; Szmigielska, Barbara; Vanno, Vitanya; Wang, Lei; Yik, Michelle; Terracciano, Antonio

2015-01-01

Although large international studies have found consistent patterns of sex differences in personality traits among adults (i.e., women scoring higher on most facets), less is known about cross-cultural sex differences in adolescent personality and the role of culture and age in shaping them. The present study examines NEO Personality Inventory-3 (NEO-PI-3, McCrae, Costa, & Martin, 2005) informant ratings of adolescents from 23 cultures (N = 4,850) and investigates culture and age as sources of variability in sex differences of adolescents’ personality. The effect for Neuroticism (with females scoring higher than males) begins to take on its adult form around age 14. Girls score higher on Openness to Experience and Conscientiousness at all ages between 12 and 17 years. A more complex pattern emerges for Extraversion and Agreeableness, although by age 17, sex differences for these traits are highly similar to those observed in adulthood. Cross-sectional data suggest that (1) with advancing age, sex differences found in adolescents increasingly converge towards adult patterns with respect to both direction and magnitude; (2) girls display sex-typed personality traits at an earlier age than boys; and (3) the emergence of sex differences was similar across culture. Practical implications of the present findings are discussed. PMID:25603371

A Note on Sex Differences in Mental Rotation in Different Age Groups

ERIC Educational Resources Information Center

Geiser, Christian; Lehmann, Wolfgang; Eid, Michael

2008-01-01

A large number of studies have reported average performance differences in favor of males in mental rotation tasks. However, it is still unclear to what extent the magnitude of the sex differences varies across age, and whether the differences increase with age. In this study, we reanalyzed data from a cross-sectional investigation of N = 1624…

Sex and gender differences in therapy of type 2 diabetes.

PubMed

Kautzky-Willer, Alexandra; Harreiter, Jürgen

2017-09-01

Clinical guidelines for the management of type 2 diabetes recommend individual therapy considering age, duration of disease, presence of complication and risk of hypoglycaemia. However, at present, the patient's sex has no impact on clinical decisions. Yet, there is mounting data pointing at biological and psychosocial differences between men and women with great impact on progression of disease and complications. Moreover, choices and preferences of therapeutic strategies as well as adherence to lifestyle and pharmacological interventions differ in both sexes. In addition, drug therapy may have sex-specific side effects. Therefore, there is need of more research on biological differences and of evidence-based individualised targeted sex-sensitive therapeutic concepts. Clinical guidelines must consider relevant sex-differences. Development and implementation of sex-specific programs may help to improve adherence to therapy and to reduce progression of disease and development of complications. A more gender-sensitive clinical approach may improve quality of life and increase health and life expectancy in men and women with type 2 diabetes. Copyright © 2017 Elsevier B.V. All rights reserved.

Despite higher glucocorticoid levels and stress responses in female rats, both sexes exhibit similar stress-induced changes in hippocampal neurogenesis.

PubMed

Hulshof, Henriëtte J; Novati, Arianna; Luiten, Paul G M; den Boer, Johan A; Meerlo, Peter

2012-10-01

Sex differences in stress reactivity may be one of the factors underlying the increased sensitivity for the development of psychopathologies in women. Particularly, an increased hypothalamic-pituitary-adrenal (HPA) axis reactivity in females may exacerbate stress-induced changes in neuronal plasticity and neurogenesis, which in turn may contribute to an increased sensitivity to psychopathology. The main aim of the present study was to examine male-female differences in stress-induced changes in different aspects of hippocampal neurogenesis, i.e. cell proliferation, differentiation and survival. Both sexes were exposed to a wide variety of stressors, where after differences in HPA-axis reactivity and neurogenesis were assessed. To study the role of oestradiol in potential sex differences, ovariectomized females received low or high physiological oestradiol level replacement pellets. The results show that females in general have a higher basal and stress-induced HPA-axis activity than males, with minimal differences between the two female groups. Cell proliferation in the dorsal hippocampus was significantly higher in high oestradiol females compared to low oestradiol females and males, while doublecortin (DCX) expression as a marker of cell differentiation was significantly higher in males compared to females, independent of oestradiol level. Stress exposure did not significantly influence cell proliferation or survival of new cells, but did reduce DCX expression. In conclusion, despite the male-female differences in HPA-axis activity, the effect of repeated stress exposure on hippocampal cell differentiation was not significantly different between sexes. Copyright © 2012 Elsevier B.V. All rights reserved.

Sex differences in the response to apomorphine in rats.

PubMed

Masur, J; Boerngen, R; Tufik, S

1980-01-01

The response of male and female rats to the hypothermic and verticalization effect (climbing behavior) induced by different doses of apomorphine was studied. A clear sex difference was observed, males showing more verticalization than females. Conversely the females showed a greater decrease in body temperature than males. The verticalization response was also studied in rats of both sexes at seven different ages, varying from 15 to 100 days. At the earlier ages, both groups presented low levels of verticalization. Mature males (60-100 days of age) increased the verticalization response to apomorphine.

Identifying and managing chest pain in women.

PubMed

Wyant, Andrew R; Collett, DeShana

2015-01-01

Heart disease continues to be the leading cause of death in women in the United States. Sex disparities remain despite research highlighting the unique aspects of managing women with ischemic heart disease. Increased mortality in women may be related to the critical differences in the clinical presentation of ischemic heart disease between the sexes. Sex-related differences in the pathophysiology of ischemic heart disease also influence diagnostic testing and management. This article reviews the differences in diagnosis and management between men and women with ischemic heart disease.

Sex differences in the outcomes of stent implantation in mini-swine model.

PubMed

Kunio, Mie; Wong, Gee; Markham, Peter M; Edelman, Elazer R

2018-01-01

Sex-related differences have been noted in cardiovascular anatomy, pathophysiology, and treatment responses, yet we continued to drive evaluation of vascular device development in animal models without consideration of animal sex. We aimed to understand sex-related differences in the vascular responses to stent implantation by analyzing the pooled data of endovascular interventions in 164 Yucatan mini-swine (87 female, 77 male). Bare metal stents (BMS) or drug-eluting stents (DES) were implanted in 212 coronary arteries (63 single BMS implantation, 68 single DES implantation, 33 overlapped BMS implantation, and 48 overlapped DES implantation). Histomorphological parameters were evaluated from vascular specimens at 3-365 days after stent implantation and evaluated values were compared between female and male groups. While neointima formation at all times after implantation was invariant to sex, statistically significant differences between female and male groups were observed in injury, inflammation, adventitial fibrosis, and neointimal fibrin deposition. These differences were observed independently, i.e., for different procedure types and at different follow-up timings. Only subtle temporal sex-related differences were observed in extent and timing of resolution of inflammation and fibrin clearance. These subtle sex-related differences may be increasingly important as interventional devices meld novel materials that erode and innovations in drug delivery. Erodible materials may act differently if inflammation has a different temporal sequence with sex, and drug distribution after balloon or stent delivery might be different if the fibrin clearance speaks to different modes of pharmacokinetics in male and female swine.

The Size Advantage Model of Sex Allocation in the Protandrous Sex-Changer Crepidula fornicata: Role of the Mating System, Sperm Storage, and Male Mobility.

PubMed

Broquet, Thomas; Barranger, Audrey; Billard, Emmanuelle; Bestin, Anastasia; Berger, Rémy; Honnaert, Gaelle; Viard, Frédérique

2015-09-01

Sequential hermaphroditism is adaptive when the reproductive value of an individual varies with size or age, and this relationship differs between males and females. In this case, theory shows that the lifetime reproductive output of an individual is increased by changing sex (a hypothesis referred to as the size-advantage model). Sex-linked differences in size-fitness curves can stem from differential costs of reproduction, the mating system, and differences in growth and mortality between sexes. Detailed empirical data is required to disentangle the relative roles of each of these factors within the theory. Quantitative data are also needed to explore the role of sperm storage, which has not yet been considered with sequential hermaphrodites. Using experimental rearing and paternity assignment, we report relationships between size and reproductive success of Crepidula fornicata, a protandrous (male-first) gastropod. Male reproductive success increased with size due to the polygamous system and stacking behavior of the species, but females nonetheless had greater reproductive success than males of the same size, in agreement with the size-advantage theory. Sperm storage appeared to be a critical determinant of success for both sexes, and modeling the effect of sperm storage showed that it could potentially accelerate sex change in protandrous species.

Sputum, sex and scanty smears: new case definition may reduce sex disparities in smear-positive tuberculosis.

PubMed

Ramsay, A; Bonnet, M; Gagnidze, L; Githui, W; Varaine, F; Guérin, P J

2009-05-01

Urban clinic, Nairobi. To evaluate the impact of specimen quality and different smear-positive tuberculosis (TB) case (SPC) definitions on SPC detection by sex. Prospective study among TB suspects. A total of 695 patients were recruited: 644 produced > or =1 specimen for microscopy. The male/female sex ratio was 0.8. There were no significant differences in numbers of men and women submitting three specimens (274/314 vs. 339/380, P = 0.43). Significantly more men than women produced a set of three 'good' quality specimens (175/274 vs. 182/339, P = 0.01). Lowering thresholds for definitions to include scanty smears resulted in increases in SPC detection in both sexes; the increase was significantly higher for women. The revised World Health Organization (WHO) case definition was associated with the highest detection rates in women. When analysis was restricted only to patients submitting 'good' quality specimen sets, the difference in detection between sexes was on the threshold for significance (P = 0.05). Higher SPC notification rates in men are commonly reported by TB control programmes. The revised WHO SPC definition may reduce sex disparities in notification. This should be considered when evaluating other interventions aimed at reducing these. Further study is required on the effects of the human immuno-deficiency virus and instructed specimen collection on sex-specific impact of new SPC definition.

Females scan more than males: a potential mechanism for sex differences in recognition memory.

PubMed

Heisz, Jennifer J; Pottruff, Molly M; Shore, David I

2013-07-01

Recognition-memory tests reveal individual differences in episodic memory; however, by themselves, these tests provide little information regarding the stage (or stages) in memory processing at which differences are manifested. We used eye-tracking technology, together with a recognition paradigm, to achieve a more detailed analysis of visual processing during encoding and retrieval. Although this approach may be useful for assessing differences in memory across many different populations, we focused on sex differences in face memory. Females outperformed males on recognition-memory tests, and this advantage was directly related to females' scanning behavior at encoding. Moreover, additional exposures to the faces reduced sex differences in face recognition, which suggests that males may be able to improve their recognition memory by extracting more information at encoding through increased scanning. A strategy of increased scanning at encoding may prove to be a simple way to enhance memory performance in other populations with memory impairment.

Stress amplifies sex differences in primate prefrontal profiles of gene expression.

PubMed

Lee, Alex G; Hagenauer, Megan; Absher, Devin; Morrison, Kathleen E; Bale, Tracy L; Myers, Richard M; Watson, Stanley J; Akil, Huda; Schatzberg, Alan F; Lyons, David M

2017-11-02

Stress is a recognized risk factor for mood and anxiety disorders that occur more often in women than men. Prefrontal brain regions mediate stress coping, cognitive control, and emotion. Here, we investigate sex differences and stress effects on prefrontal cortical profiles of gene expression in squirrel monkey adults. Dorsolateral, ventrolateral, and ventromedial prefrontal cortical regions from 18 females and 12 males were collected after stress or no-stress treatment conditions. Gene expression profiles were acquired using HumanHT-12v4.0 Expression BeadChip arrays adapted for squirrel monkeys. Extensive variation between prefrontal cortical regions was discerned in the expression of numerous autosomal and sex chromosome genes. Robust sex differences were also identified across prefrontal cortical regions in the expression of mostly autosomal genes. Genes with increased expression in females compared to males were overrepresented in mitogen-activated protein kinase and neurotrophin signaling pathways. Many fewer genes with increased expression in males compared to females were discerned, and no molecular pathways were identified. Effect sizes for sex differences were greater in stress compared to no-stress conditions for ventromedial and ventrolateral prefrontal cortical regions but not dorsolateral prefrontal cortex. Stress amplifies sex differences in gene expression profiles for prefrontal cortical regions involved in stress coping and emotion regulation. Results suggest molecular targets for new treatments of stress disorders in human mental health.

Perils and pitfalls of reporting sex differences

PubMed Central

Maney, Donna L.

2016-01-01

The idea of sex differences in the brain both fascinates and inflames the public. As a result, the communication and public discussion of new findings is particularly vulnerable to logical leaps and pseudoscience. A new US National Institutes of Health policy to consider both sexes in almost all preclinical research will increase the number of reported sex differences and thus the risk that research in this important area will be misinterpreted and misrepresented. In this article, I consider ways in which we might reduce that risk, for example, by (i) employing statistical tests that reveal the extent to which sex explains variation, rather than whether or not the sexes ‘differ’, (ii) properly characterizing the frequency distributions of scores or dependent measures, which nearly always overlap, and (iii) avoiding speculative functional or evolutionary explanations for sex-based variation, which usually invoke logical fallacies and perpetuate sex stereotypes. Ultimately, the factor of sex should be viewed as an imperfect, temporary proxy for yet-unknown factors, such as hormones or sex-linked genes, that explain variation better than sex. As scientists, we should be interested in discovering and understanding the true sources of variation, which will be more informative in the development of clinical treatments. PMID:26833839

Sex hormone binding globulin and sex steroids among premenopausal women in the diabetes prevention program.

PubMed

Kim, Catherine; Pi-Sunyer, Xavier; Barrett-Connor, Elizabeth; Stentz, Frankie B; Murphy, Mary Beth; Kong, Shengchun; Nan, Bin; Kitabchi, Abbas E

2013-07-01

It is unknown whether intensive lifestyle modification (ILS) or metformin changes sex steroids among premenopausal women without a history of polycystic ovarian syndrome (PCOS). We examined 1-year intervention impact on sex steroids (estradiol, testosterone, dehydroepiandrosterone, and androstenedione [A4]) and SHBG and differences by race/ethnicity. A subgroup of Diabetes Prevention Program participants who were premenopausal, not using estrogen, without a history of PCOS or irregular menses, and who reported non-Hispanic white (NHW), Hispanic, or African-American race/ethnicity (n = 301). Randomization arms were 1) ILS with the goals of weight reduction of 7% of initial weight and 150 minutes per week of moderate intensity exercise, 2) metformin 850 mg twice a day, or 3) placebo. Neither intervention changed sex steroids compared to placebo. ILS, but not metformin, increased median SHBG by 3.1 nmol/L (~11%) compared to decreases of 1.1 nmol/L in the placebo arm (P < .05). This comparison remained significant after adjustment for changes in covariates including waist circumference. However, associations with glucose were not significant. Median baseline A4 was lower in Hispanics compared to NHWs (5.7 nmol/L vs 6.5 nmol/L, P < .05) and increases in A4 were greater in Hispanics compared to NHWs (3.0 nmol/ vs 1.2 nmol/L, P < .05), and these differences did not differ significantly by intervention arm. No other racial/ethnic differences were significant. Among premenopausal glucose-intolerant women, no intervention changed sex steroids. ILS increased SHBG, although associations with glucose were not significant. SHBG and sex steroids were similar by race/ethnicity, with the possible exception of lower baseline A4 levels in Hispanics compared to NHWs.

IL-4 Is Required for Sex Differences in Vulnerability to Focal Ischemia in Mice.

PubMed

Xiong, Xiaoxing; Xu, Lijun; Wei, Liang; White, Robin E; Ouyang, Yi-Bing; Giffard, Rona G

2015-08-01

Interleukin (IL)-4 protects from middle cerebral artery occlusion in male mice. Females generally show less injury in response to the same ischemic challenge, but the underlying mechanisms are not fully understood. We tested the importance of IL-4 in female protection using IL-4 knockout (KO) mice. IL-4 KO and wild-type (WT) mice of both sexes were subjected to middle cerebral artery occlusion. Infarct volume was assessed by triphenyltetrazolium chloride staining and neurobehavioral outcome by neuroscore. T cell proliferation was assessed after Concanavalin A exposure. Ischemic brain immune cell populations were analyzed by fluorescence-activated cell sorting and immunostaining. Infarction in WT females during estrus and proestrus phases was significantly smaller than in males; neurological score was better. Infarction volume was larger and neurological score worse in IL-4 KO compared with WT in both sexes, with no sex difference. Proliferation of T cells was inhibited in WT females with higher proliferation and no sex difference in IL-4 KO. Macrophage numbers and total T cells in the ischemic hemisphere were lower in WT females, and monocytes increased markedly in IL-4 KOs with no sex difference. The reduced macrophage infiltration in WT-females was predominantly M2. Loss of IL-4 increased CD68+ and iNOS+ cells and reduced YM1+ and Arg1+ cells in both sexes. IL-4 is required for female neuroprotection during the estrus phase of the estrus cycle. Protected WT females show a predominance of M2-activated microglia/macrophages and reduced inflammatory infiltration. Increasing macrophage M2 polarization, with or without added inhibition of infiltration, may be a new approach to stroke treatment. © 2015 American Heart Association, Inc.

Sex differences in antiplatelet response in ischemic stroke.

PubMed

Meyer, Dawn M; Eastwood, Jo-Ann; Compton, Margaret P; Gylys, Karen; Zivin, Justin A; Ovbiagele, Bruce

2011-07-01

Sex differences exist in the occurrence, treatment and outcome of ischemic stroke. Compared with men, women have more stroke events and are less likely to fully recover from a stroke. Given the rapidly aging population, stroke incidence and mortality among women are projected to substantially rise by 2050. This has important public health consequences. Mitigating the burden of stroke among women will require a fundamental understanding of sex differences and sex-specific issues including cerebrovascular disease pathophysiology, treatment and outcome. An aspect of stroke treatment receiving increasing but insufficient attention involves possible interactions between estrogen levels, antiplatelet drugs and stroke outcome. Emerging evidence suggests that antiplatelet therapy may provide primary stroke protection but not primary myocardial infarction prevention in women, while the opposite may be true among men. Understanding sex-specific issues related to women who experience stroke is critical to clinicians who treat women with antiplatelet medications as part of a secondary stroke prevention regimen; however, the ideal antiplatelet medication, and dose, in women requires further research. In this article we present a conceptual framework for sex differences in antiplatelet treatment response in ischemic stroke, thrombus formation and the mediating role of estrogen, sex differences in antiplatelet treatment response in clinical trials, and sex differences in antiplatelet treatment use in ischemic stroke.

Sex differences in antiplatelet response in ischemic stroke

PubMed Central

Meyer, Dawn M; Eastwood, Jo-Ann; Compton, Margaret P; Gylys, Karen; Zivin, Justin A; Ovbiagele, Bruce

2011-01-01

Sex differences exist in the occurrence, treatment and outcome of ischemic stroke. Compared with men, women have more stroke events and are less likely to fully recover from a stroke. Given the rapidly aging population, stroke incidence and mortality among women are projected to substantially rise by 2050. This has important public health consequences. Mitigating the burden of stroke among women will require a fundamental understanding of sex differences and sex-specific issues including cerebrovascular disease pathophysiology, treatment and outcome. An aspect of stroke treatment receiving increasing but insufficient attention involves possible interactions between estrogen levels, antiplatelet drugs and stroke outcome. Emerging evidence suggests that antiplatelet therapy may provide primary stroke protection but not primary myocardial infarction prevention in women, while the opposite may be true among men. Understanding sex-specific issues related to women who experience stroke is critical to clinicians who treat women with antiplatelet medications as part of a secondary stroke prevention regimen; however, the ideal antiplatelet medication, and dose, in women requires further research. In this article we present a conceptual framework for sex differences in antiplatelet treatment response in ischemic stroke, thrombus formation and the mediating role of estrogen, sex differences in antiplatelet treatment response in clinical trials, and sex differences in antiplatelet treatment use in ischemic stroke. PMID:21790339

Mechanisms of Sex Differences in Fear and Posttraumatic Stress Disorder.

PubMed

Ramikie, Teniel Sonya; Ressler, Kerry J

2018-05-15

Following sexual maturity, females disproportionately have higher rates of posttraumatic stress disorder (PTSD) and experience greater symptom severity and chronicity as compared with males. This observation has led many to examine sex differences in PTSD risk factors. Though relatively few, these studies reveal that the root causes of PTSD sex differences are complex, and partly represent interactions between sex-specific nonbiological and biological risk factors, which differentially shape PTSD vulnerability. Moreover, these studies suggest that sex-specific PTSD vulnerability is partly regulated by sex differences in fear systems. Fear, which represents a highly conserved adaptive response to threatening environmental stimuli, becomes pathological in trauma- and stress-based psychiatric syndromes, such as PTSD. Over the last 30 years, considerable progress has been made in understanding normal and pathological molecular and behavioral fear processes in humans and animal models. Thus, fear mechanisms represent a tractable PTSD biomarker in the study of sex differences in fear. In this review, we discuss studies that examine nonbiological and biological sex differences that contribute to normal and pathological fear behaviors in humans and animal models. This, we hope, will shed greater light on the potential mechanisms that contribute to increased PTSD vulnerability in females. Copyright © 2017 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Sex differences in oxidative stress resistance in relation to longevity in Drosophila melanogaster.

PubMed

Niveditha, S; Deepashree, S; Ramesh, S R; Shivanandappa, T

2017-10-01

Gender differences in lifespan and aging are known across species. Sex differences in longevity within a species can be useful to understand sex-specific aging. Drosophila melanogaster is a good model to study the problem of sex differences in longevity since females are longer lived than males. There is evidence that stress resistance influences longevity. The objective of this study was to investigate if there is a relationship between sex differences in longevity and oxidative stress resistance in D. melanogaster. We observed a progressive age-dependent decrease in the activity of SOD and catalase, major antioxidant enzymes involved in defense mechanisms against oxidative stress in parallel to the increased ROS levels over time. Longer-lived females showed lower ROS levels and higher antioxidant enzymes than males as a function of age. Using ethanol as a stressor, we have shown differential susceptibility of the sexes to ethanol wherein females exhibited higher resistance to ethanol-induced mortality and locomotor behavior compared to males. Our results show strong correlation between sex differences in oxidative stress resistance, antioxidant defenses and longevity. The study suggests that higher antioxidant defenses in females may confer resistance to oxidative stress, which could be a factor that influences sex-specific aging in D. melanogaster.

Fetal sex-based differences in maternal hormones, angiogenic factors, and immune mediators during pregnancy and the postpartum period.

PubMed

Enninga, Elizabeth Ann L; Nevala, Wendy K; Creedon, Douglas J; Markovic, Svetomir N; Holtan, Shernan G

2015-03-01

Several pregnancy complications have disparities based on the sex of the fetus. It is unknown whether the sex of the fetus differentially alters the maternal immune milieu, potentially contributing to the observed differences. Using maternal plasma collected during 38 uncomplicated pregnancies (19 males, 19 females), we compared levels of cytokines, sex hormones, and angiogenic factors throughout gestation and postpartum. Male fetal sex was associated with higher levels of proinflammatory cytokines (G-CSF, IL-12p70, IL-21, and IL-33) and angiogenic factors (PlGF and VEGF-A) compared with female fetal sex at multiple timepoints. Female fetal sex was associated with higher levels of regulatory cytokines (IL-5, IL-9, IL-17, and IL-25). IL-27 increased throughout pregnancy regardless of fetal sex. There was no fetal sex-based difference in analyte concentrations at the postpartum measurement. Women carrying a male fetus exhibit a more proinflammatory/proangiogenic immune milieu than women carrying a female fetus. © 2014 The Authors. American Journal of Reproductive Immunology Published by John Wiley & Sons Ltd.

Fetal Sex-Based Differences in Maternal Hormones, Angiogenic Factors, and Immune Mediators During Pregnancy and the Postpartum Period

PubMed Central

Enninga, Elizabeth Ann L; Nevala, Wendy K; Creedon, Douglas J; Markovic, Svetomir N; Holtan, Shernan G

2015-01-01

Problem Several pregnancy complications have disparities based on the sex of the fetus. It is unknown whether the sex of the fetus differentially alters the maternal immune milieu, potentially contributing to the observed differences. Method of study Using maternal plasma collected during 38 uncomplicated pregnancies (19 males, 19 females), we compared levels of cytokines, sex hormones, and angiogenic factors throughout gestation and postpartum. Results Male fetal sex was associated with higher levels of proinflammatory cytokines (G-CSF, IL-12p70, IL-21, and IL-33) and angiogenic factors (PlGF and VEGF-A) compared with female fetal sex at multiple timepoints. Female fetal sex was associated with higher levels of regulatory cytokines (IL-5, IL-9, IL-17, and IL-25). IL-27 increased throughout pregnancy regardless of fetal sex. There was no fetal sex-based difference in analyte concentrations at the postpartum measurement. Conclusion Women carrying a male fetus exhibit a more proinflammatory/proangiogenic immune milieu than women carrying a female fetus. PMID:25091957

Sex difference in PCB concentrations of a catostomid fish

USGS Publications Warehouse

Madenjian, Charles P.; Stevens, Andrew L.; Stapanian, Martin A.; Batterman, Stuart A.; Chernyak, Sergei M.; Menczer, Jordan E.; McIntyre, Peter B.

2017-01-01

Unraveling the complexities associated with the relative differences in contaminant concentrations between the sexes of mature fish may provide insights into important behavioral and physiological differences between the sexes of not just fish but higher vertebrates as well. Whole-fish polychlorinated biphenyl (PCB) concentrations were determined in 25 mature female white suckers (Catostomus commersoni) and 26 mature male white suckers caught during their spawning run in the Kewaunee River, a tributary to Lake Michigan. Total length and weight were measured for each fish, and age of each fish was estimated from thin-sectioned otoliths. PCB concentration significantly increased with increasing total length, weight, and age. Consequently, three analysis of covariance (ANCOVA) models were fitted to the data to assess the effect of sex on white sucker PCB concentration. Based on model averaging, estimates of mean PCB concentrations in female and male white suckers were 185 and 219 ng/g, respectively. Thus, males were 18% greater in PCB concentration than females. We conclude that this difference between the sexes was most likely mainly driven by a higher rate of energy expenditure in males compared with females. Greater energy expenditure, owing to greater swimming activity and a higher resting metabolic rate, resulted in a higher rate of food consumption, which in turn led to a greater rate of PCB accumulation. Higher whole-fish PCB concentration in males compared with females has now been shown in nine different fish species. Our study represented the first documentation of this type of sex difference in a catostomid fish.

Effects of age and sex on developmental neural networks of visual-spatial attention allocation.

PubMed

Rubia, Katya; Hyde, Zoe; Halari, Rozmin; Giampietro, Vincent; Smith, Anna

2010-06-01

Compared to our understanding of the functional maturation of brain networks underlying complex cognitive abilities, hardly anything is known of the neurofunctional development of simpler cognitive abilities such as visuo-spatial attention allocation. Furthermore, nothing is known on the effect of gender on the functional development of attention allocation. This study employed event related functional magnetic resonance imaging to investigate effects of age, sex, and sex by age interactions on the brain activation of 63 males and females, between 13 to 38years, during a visual-spatial oddball task. Behaviourally, with increasing age, speed was traded for accuracy, indicative of a less impulsive performance style in older subjects. Increasing age was associated with progressively increased activation in typical areas of selective attention of lateral fronto-striatal and temporo-parietal brain regions. Sex difference analysis showed enhanced activation in right-hemispheric inferior frontal and superior temporal regions in females, and in left-hemispheric inferior temporo-parietal regions in males. Importantly, the age by sex interaction findings showed that these sex-dimorphic patterns of brain activation may be the result of underlying sex differences in the functional maturation of these brain regions, as females had sex-specific progressive age-correlations in the same right inferior fronto-striato-temporal areas, while male-specific age-correlations were in left medial temporal and parietal areas. The findings demonstrate progressive functional maturation of fronto-striato-parieto-temporal networks of the relatively simple function of attention allocation between early adolescence and mid-adulthood. They furthermore show that sex-dimorphic patterns of enhanced reliance on right inferior frontal, striatal and superior temporal regions in females and of left temporo-parietal regions in males during attention allocation may be the result of underlying sex differences in the functional maturation of these brain regions. Copyright 2010 Elsevier Inc. All rights reserved.

Genetic and hormonal control of hepatic steatosis in female and male mice.

PubMed

Norheim, Frode; Hui, Simon T; Kulahcioglu, Emre; Mehrabian, Margarete; Cantor, Rita M; Pan, Calvin; Parks, Brian W; Lusis, Aldons J

2017-01-01

The etiology of nonalcoholic fatty liver disease is complex and influenced by factors such as obesity, insulin resistance, hyperlipidemia, and sex. We now report a study on sex difference in hepatic steatosis in the context of genetic variation using a population of inbred strains of mice. While male mice generally exhibited higher concentration of hepatic TG levels on a high-fat high-sucrose diet, sex differences showed extensive interaction with genetic variation. Differences in percentage body fat were the best predictor of hepatic steatosis among the strains and explained about 30% of the variation in both sexes. The difference in percent gonadal fat and HDL explained 9.6% and 6.7% of the difference in hepatic TGs between the sexes, respectively. Genome-wide association mapping of hepatic TG revealed some striking differences in genetic control of hepatic steatosis between females and males. Gonadectomy increased the hepatic TG to body fat percentage ratio among male, but not female, mice. Our data suggest that the difference between the sexes in hepatic TG can be partly explained by differences in body fat distribution, plasma HDL, and genetic regulation. Future studies are required to understand the molecular interactions between sex, genetics, and the environment. Copyright © 2017 by the American Society for Biochemistry and Molecular Biology, Inc.

Effects of Sex and Gender on Adaptation to Space: Neurosensory Systems

PubMed Central

Cohen, Helen S.; Cerisano, Jody M.; Clayton, Janine A.; Cromwell, Ronita; Danielson, Richard W.; Hwang, Emma Y.; Tingen, Candace; Allen, John R.; Tomko, David L.

2014-01-01

Abstract Sex and gender differences have long been a research topic of interest, yet few studies have explored the specific differences in neurological responses between men and women during and after spaceflight. Knowledge in this field is limited due to the significant disproportion of sexes enrolled in the astronaut corps. Research indicates that general neurological and sensory differences exist between the sexes, such as those in laterality of amygdala activity, sensitivity and discrimination in vision processing, and neuronal cell death (apoptosis) pathways. In spaceflight, sex differences may include a higher incidence of entry and space motion sickness and of post-flight vestibular instability in female as opposed to male astronauts who flew on both short- and long-duration missions. Hearing and auditory function in crewmembers shows the expected hearing threshold differences between men and women, in which female astronauts exhibit better hearing thresholds. Longitudinal observations of hearing thresholds for crewmembers yield normal age-related decrements; however, no evidence of sex-related differences from spaceflight has been observed. The impact of sex and gender differences should be studied by making spaceflight accessible and flying more women into space. Only in this way will we know if increasingly longer-duration missions cause significantly different neurophysiological responses in men and women. PMID:25401941

Peer Influences on Sexual Activity among Adolescents in Ghana.

PubMed

Bingenheimer, Jeffrey B; Asante, Elizabeth; Ahiadeke, Clement

2015-03-01

Little is known about the influences of peers on the sexual activity of adolescents in sub-Saharan Africa. Better understanding of these issues could lead to more effective sexual and reproductive health interventions. Using two waves of survey data from 1,275 adolescents in two southeastern Ghanaian towns, we examine age, sex, and community differences in peer group characteristics. We also examine prospective associations between peer group characteristics and self-reported sexual initiation and multiple partnerships during a 20-month follow-up period. Sex differences in peer-context variables were small. Affiliation with antisocial peers and perceived peer norms favoring sex increased the odds of transition to first sex. Having more friends increased the odds among younger respondents of acquiring multiple new sexual partners. Among males, perceived peer norms favoring sex increased the odds of acquiring multiple partners. We discuss the implications of these findings for adolescent sexual and reproductive health intervention strategies in sub-Saharan Africa, and conclude that peer-based interventions may be best suited to the needs of at-risk adolescent boys. © 2015 The Population Council, Inc.

The Relevance of Sex Differences in Performance Fatigability

PubMed Central

Hunter, Sandra K.

2016-01-01

Performance fatigability differs between men and women for a range of fatiguing tasks. Women are usually less fatigable than men and this is most widely described for isometric fatiguing contractions, and some dynamic tasks. The sex difference in fatigability is specific to the task demands so that one mechanism is not universal, including any sex differences in skeletal muscle physiology, muscle perfusion and voluntary activation. However, there are substantial knowledge gaps about the task dependency of the sex differences in fatigability, the involved mechanisms and the relevance to clinical populations and with advanced age. The knowledge gaps are in part due to the significant deficits in the number of women included in performance fatigability studies despite a gradual increase in the inclusion of women over the last 20 years. Therefore, this review 1) provides a rationale for the limited knowledge about sex differences in performance fatigability, 2) summarizes the current knowledge on sex differences in fatigability and the potential mechanisms across a range of tasks, 3) highlights emerging areas of opportunity in clinical populations, and 4) suggests strategies to close the knowledge gap and understanding the relevance of sex differences in performance fatigability. The limited understanding about sex differences in fatigability in healthy and clinical populations, presents as a field ripe with opportunity for high impact studies. Such studies will inform on the limitations of men and women during athletic endeavors, ergonomic tasks and daily activities. Because fatigability is required for effective neuromuscular adaptation, sex differences in fatigability studies will also inform on optimal strategies for training and rehabilitation in both men and women. PMID:27015385

Sex Commonalities and Differences in Obesity-Related Alterations in Intrinsic Brain Activity and Connectivity.

PubMed

Gupta, Arpana; Mayer, Emeran A; Labus, Jennifer S; Bhatt, Ravi R; Ju, Tiffany; Love, Aubrey; Bal, Amanat; Tillisch, Kirsten; Naliboff, Bruce; Sanmiguel, Claudia P; Kilpatrick, Lisa A

2018-02-01

This study aimed to characterize obesity-related sex differences in the intrinsic activity and connectivity of the brain's reward networks. Eighty-six women (n = 43) and men (n = 43) completed a 10-minute resting functional magnetic resonance imaging scan. Sex differences and commonalities in BMI-related frequency power distribution and reward seed-based connectivity were investigated by using partial least squares analysis. For whole-brain activity in both men and women, increased BMI was associated with increased slow-5 activity in the left globus pallidus (GP) and substantia nigra. In women only, increased BMI was associated with increased slow-4 activity in the right GP and bilateral putamen. For seed-based connectivity in women, increased BMI was associated with reduced slow-5 connectivity between the left GP and putamen and the emotion and cortical regulation regions, but in men, increased BMI was associated with increased connectivity with the medial frontal cortex. In both men and women, increased BMI was associated with increased slow-4 connectivity between the right GP and bilateral putamen and the emotion regulation and sensorimotor-related regions. The stronger relationship between increased BMI and decreased connectivity of core reward network components with cortical and emotion regulation regions in women may be related to the greater prevalence of emotional eating. The present findings suggest the importance of personalized treatments for obesity that consider the sex of the affected individual. © 2017 The Obesity Society.

Risk Factors for Orthostatic Hypotension: Differences Between Elderly Men and Women.

PubMed

Méndez, Andrea S; Melgarejo, Jesús D; Mena, Luis J; Chávez, Carlos A; González, Alicex C; Boggia, José; Terwilliger, Joseph D; Lee, Joseph H; Maestre, Gladys E

2018-06-11

Orthostatic hypotension (OH) occurs when mechanisms regulating blood pressure (BP) levels after standing-up are altered. It is unclear how prevalence and risk factors for OH are different between sexes. We aimed to investigate sex differences in prevalence and risk factors for OH elderly individuals. We included 882 participants from Maracaibo Aging Study. OH was a sustained reduction of ≥20 mm Hg in systolic BP, ≥10 mm Hg in diastolic BP, or both, after 3 minutes of changing positions from supine to standing. Multivariable logistic regression models were used to examine the relationships among risk factors for OH in men and women considering interaction sex-term and stratified by sex. The mean age was 66.7 ± 8.5 years, being similar by sex. Women and men 55-74 years had similar prevalence of OH+ (18.5% vs. 20.9%, respectively). After 75 years, the proportion of women with OH+ was lower than men (11% vs. 30%, respectively). Hypertension, specifically systolic BP ≥140 mm Hg, and high pulse pressure (PP) were related with OH+ accounted by interaction sex-term, while diastolic BP ≥90 mm Hg, antihypertensive treatment, body mass index (BMI), diabetes mellitus and age were not. Systolic BP ≥140 mm Hg increases the risk of OH only among women, while BMI showed an inverse association in both sexes. Although the prevalence of OH is similar in both sexes, there are different risk factors associated by sex. Systolic BP ≥140 mm Hg was associated with increased risk of OH only with women while BMI was a protective factor for OH in men and women.

Risk of Sex-Specific Cancers in Opposite-Sex and Same-Sex Twins in Denmark and Sweden

PubMed Central

Ahrenfeldt, Linda J.; Skytthe, Axel; Möller, Sören; Czene, Kamila; Adami, Hans-Olov; Mucci, Lorelei A.; Kaprio, Jaakko; Petersen, Inge; Christensen, Kaare; Lindahl-Jacobsen, Rune

2016-01-01

Background Increasing evidence shows that some cancers originate in utero. It is hypothesized that elevated exposure to some steroid hormones might increase cancer risk and that hormone transfer between twin fetuses could result in different prenatal exposure to testosterone. Methods This large-scale prospective twin study compared opposite-sex (OS) and same-sex (SS) twins to test the impact of intrauterine exposures on cancer risk. On the basis of the Danish and Swedish twin and cancer registries, we calculated incidence rate ratios for OS and SS twins, whereas standardized incidence ratios (SIR) with 95% confidence intervals (CI) were calculated for OS/SS twins compared with the general population. Results Atotal of 18,001 cancers were identified during 1943–2009. No significant differences were observed between OS and SS twins, neither for the sex-specific cancers nor for cancer at all sites. All-cause cancer was slightly reduced for OS and SS twins compared with the general population, significant for OS males (SIR, 0.95; 95% CI, 0.92–0.98) and for SS males and females (SIR, 0.97; 95% CI, 0.94–0.99). Conclusions Our data suggest that having a male co-twin—which may entail higher exposure to prenatal testosterone—does not increase the risk of sex-specific cancers in OS females. Furthermore, the study supports that twinning per se is not a risk factor of cancer. Impact Findings are reassuring, as they fail to provide evidence for the hypothesis that endocrine or other difference in the in utero milieu affects the risk of sex-specific cancers. PMID:26282631

Sex differences and emotion regulation: an event-related potential study.

PubMed

Gardener, Elyse K T; Carr, Andrea R; Macgregor, Amy; Felmingham, Kim L

2013-01-01

Difficulties in emotion regulation have been implicated as a potential mechanism underlying anxiety and mood disorders. It is possible that sex differences in emotion regulation may contribute towards the heightened female prevalence for these disorders. Previous fMRI studies of sex differences in emotion regulation have shown mixed results, possibly due to difficulties in discriminating the component processes of early emotional reactivity and emotion regulation. The present study used event-related potentials (ERPs) to examine sex differences in N1 and N2 components (reflecting early emotional reactivity) and P3 and LPP components (reflecting emotion regulation). N1, N2, P3, and LPP were recorded from 20 men and 23 women who were instructed to "increase," "decrease," and "maintain" their emotional response during passive viewing of negative images. Results indicated that women had significantly greater N1 and N2 amplitudes (reflecting early emotional reactivity) to negative stimuli than men, supporting a female negativity bias. LPP amplitudes increased to the "increase" instruction, and women displayed greater LPP amplitudes than men to the "increase" instruction. There were no differences to the "decrease" instruction in women or men. These findings confirm predictions of the female negativity bias hypothesis and suggest that women have greater up-regulation of emotional responses to negative stimuli. This finding is highly significant in light of the female vulnerability for developing anxiety disorders.

Sex differences in depression and anxiety disorders: potential biological determinants.

PubMed

Altemus, Margaret

2006-11-01

The phenomenon of higher rates of affective disorders in women illustrates many of the difficulties as well as promises of translating preclinical models to human disorders. Abnormalities in the regulation of the hypothalamic-pituitary adrenal axis and the sympathoadrenomedullary system have been identified in depression and anxiety disorders, and these disorders are clearly precipitated and exacerbated by stress. Despite the striking sex difference in the prevalence of depression and anxiety disorders, attempts to identify corresponding sex differences in stress response reactivity in animal models have met with limited success. Processes which may contribute to increased rates of affective disorders in women are greater fluxes in reproductive hormones across the life span, and increased sensitivity to catecholamine augmentation of emotional memory consolidation.

Sports injuries in women: sex- and gender-based differences in etiology and prevention.

PubMed

Templeton, Kimberly J; Hame, Sharon L; Hannafin, Jo A; Griffin, Letha Y; Tosi, Laura L; Shields, Naomi N

2008-01-01

There has been a significant increase in the participation of women in sports at all levels, especially after the enactment of the Title IX Education Amendment in 1972. This increased participation at all levels has resulted in more women sustaining sports injuries. Data on sex- and gender-based differences in all organ systems, including the musculoskeletal system, are beign gathered. It is important to review some of the areas of sex- and gender-based differences in sports injuries for which there is significant research, such as osteoporosis, the female athlete triad, and anterior cruciate ligament injuries. It is also necessary to examine those areas in which more information is needed, such as injuries to the shoulder, foot, and ankle.

Adolescent neural response to reward is related to participant sex and task motivation.

PubMed

Alarcón, Gabriela; Cservenka, Anita; Nagel, Bonnie J

2017-02-01

Risky decision making is prominent during adolescence, perhaps contributed to by heightened sensation seeking and ongoing maturation of reward and dopamine systems in the brain, which are, in part, modulated by sex hormones. In this study, we examined sex differences in the neural substrates of reward sensitivity during a risky decision-making task and hypothesized that compared with girls, boys would show heightened brain activation in reward-relevant regions, particularly the nucleus accumbens, during reward receipt. Further, we hypothesized that testosterone and estradiol levels would mediate this sex difference. Moreover, we predicted boys would make more risky choices on the task. While boys showed increased nucleus accumbens blood oxygen level-dependent (BOLD) response relative to girls, sex hormones did not mediate this effect. As predicted, boys made a higher percentage of risky decisions during the task. Interestingly, boys also self-reported more motivation to perform well and earn money on the task, while girls self-reported higher state anxiety prior to the scan session. Motivation to earn money partially mediated the effect of sex on nucleus accumbens activity during reward. Previous research shows that increased motivation and salience of reinforcers is linked with more robust striatal BOLD response, therefore psychosocial factors, in addition to sex, may play an important role in reward sensitivity. Elucidating neurobiological mechanisms that support adolescent sex differences in risky decision making has important implications for understanding individual differences that lead to advantageous and adverse behaviors that affect health outcomes. Copyright © 2016 Elsevier Inc. All rights reserved.

Sex Differences in the Impact of the Mediterranean Diet on LDL Particle Size Distribution and Oxidation.

PubMed

Bédard, Alexandra; Corneau, Louise; Lamarche, Benoît; Dodin, Sylvie; Lemieux, Simone

2015-05-15

Sex differences have been previously highlighted in the cardioprotective effects of the Mediterranean diet (MedDiet). The objective of this study was to investigate whether sex differences also exist with regard to LDL particle size distribution and oxidation. Participants were 37 men and 32 premenopausal women (24-53 years) with slightly elevated LDL-C concentrations (3.4-4.9 mmol/L) or total cholesterol/HDL-C ≥5.0. Variables were measured before and after a four-week isoenergetic MedDiet. Sex differences were found in response to the MedDiet for the proportion of medium LDL (255-260 Å) (p for sex-by-time interaction = 0.01) and small, dense LDL (sdLDL; <255 Å) (trend; p for sex-by-time interaction = 0.06), men experiencing an increase in the proportion of medium LDL with a concomitant reduction in the proportion of sdLDL, while an opposite trend was observed in women. A sex difference was also noted for estimated cholesterol concentrations among sdLDL (p for sex-by-time interaction = 0.03), with only men experiencing a reduction in response to the MedDiet. The MedDiet marginally reduced oxidized LDL (oxLDL) concentrations (p = 0.07), with no sex difference. Results suggest that short-term consumption of the MedDiet leads to a favorable redistribution of LDL subclasses from smaller to larger LDL only in men. These results highlight the importance of considering sex issues in cardiovascular benefits of the MedDiet.

Cardiovascular responses to postural changes: differences with age for women and men

NASA Technical Reports Server (NTRS)

Frey, M. A.; Tomaselli, C. M.; Hoffler, W. G.

1994-01-01

The cardiovascular responses to postural change, and how they are affected by aging, are inadequately described in women. Therefore, the authors examined the influence of age and sex on the responses of blood pressure, cardiac output, heart rate, and other variables to change in posture. Measurements were made after 10 minutes each in the supine, seated, and standing positions in 22 men and 25 women who ranged in age from 21 to 59 years. Several variables differed, both by sex and by age, when subjects were supine. On rising, subjects' diastolic and mean arterial pressures, heart rate, total peripheral resistance (TPR), and thoracic impedance increased; cardiac output, stroke volume, and mean stroke ejection rate decreased; and changes in all variables, except heart rate, were greater from supine to sitting than sitting to standing. The increase in heart rate was greater in the younger subjects, and increases in TPR and thoracic impedance were greater in the older subjects. Stroke volume decreased less, and TPR and thoracic impedance increased more, in the women than in the men. The increase in TPR was particularly pronounced in the older women. These studies show that the cardiovascular responses to standing differ, in some respects, between the sexes and with age. The authors suggest that the sex differences are, in part, related to greater decrease of thoracic blood volume with standing in women than in men, and that the age differences result, in part, from decreased responsiveness of the high-pressure baroreceptor system.

Gender-stereotyping and cognitive sex differences in mixed- and same-sex groups.

PubMed

Hirnstein, Marco; Coloma Andrews, Lisa; Hausmann, Markus

2014-11-01

Sex differences in specific cognitive abilities are well documented, but the biological, psychological, and sociocultural interactions that may underlie these differences are largely unknown. We examined within a biopsychosocial approach how gender stereotypes affect cognitive sex differences when adult participants were tested in mixed- or same-sex groups. A total of 136 participants (70 women) were allocated to either mixed- or same-sex groups and completed a battery of sex-sensitive cognitive tests (i.e., mental rotation, verbal fluency, perceptual speed) after gender stereotypes or gender-neutral stereotypes (control) were activated. To study the potential role of testosterone as a mediator for group sex composition and stereotype boost/threat effects, saliva samples were taken before the stereotype manipulation and after cognitive testing. The results showed the typical male and female advantages in mental rotation and verbal fluency, respectively. In general, men and women who were tested in mixed-sex groups and whose gender stereotypes had not been activated performed best. Moreover, a stereotype threat effect emerged in verbal fluency with reduced performance in gender stereotyped men but not women. Testosterone levels did not mediate the effects of group sex composition and stereotype threat nor did we find any relationship between testosterone and cognitive performance in men and women. Taken together, the findings suggest that an interaction of gender stereotyping and group sex composition affects the performance of men and women in sex-sensitive cognitive tasks. Mixed-sex settings can, in fact, increase cognitive performance as long as gender-stereotyping is prevented.

Sex differences in confidence influence patterns of conformity.

PubMed

Cross, Catharine P; Brown, Gillian R; Morgan, Thomas J H; Laland, Kevin N

2017-11-01

Lack of confidence in one's own ability can increase the likelihood of relying on social information. Sex differences in confidence have been extensively investigated in cognitive tasks, but implications for conformity have not been directly tested. Here, we tested the hypothesis that, in a task that shows sex differences in confidence, an indirect effect of sex on social information use will also be evident. Participants (N = 168) were administered a mental rotation (MR) task or a letter transformation (LT) task. After providing an answer, participants reported their confidence before seeing the responses of demonstrators and being allowed to change their initial answer. In the MR, but not the LT, task, women showed lower levels of confidence than men, and confidence mediated an indirect effect of sex on the likelihood of switching answers. These results provide novel, experimental evidence that confidence is a general explanatory mechanism underpinning susceptibility to social influences. Our results have implications for the interpretation of the wider literature on sex differences in conformity. © 2016 The British Psychological Society.

The prognostic impact of sex on surgically resected non-small cell lung cancer depends on clinicopathologic characteristics.

PubMed

Sterlacci, William; Tzankov, Alexandar; Veits, Lothar; Oberaigner, Wilhelm; Schmid, Thomas; Hilbe, Wolfgang; Fiegl, Michael

2011-04-01

The increasing incidence of lung cancer in women and their supposed survival advantage over men requires clarification of the significance of sex. Age, stage, histologic features, differentiation grade, and Ki-67 index were assessed in 405 surgically resected non-small cell lung cancers (NSCLCs) using a standardized tissue microarray platform. Women were associated with well/moderate tumor differentiation, a Ki-67 index of 3% or less, and adenocarcinoma histologic features. Female sex predicted increased survival time only by univariate analysis. Stratified by sex, increased survival was noted for women older than 64 years, with a tumor at postsurgical International Union Against Cancer stage I, with adenocarcinoma histologic features, with well- or moderately differentiated tumors, or with a Ki-67 index of 3% or less. Sex is not an independent prognostic parameter for patients with surgically resected NSCLC. Sex-linked differences are associated with other factors, thus simulating a prognostic impact of sex. This study elucidates sex-specific interactions between patient and tumor characteristics, which are pivotal toward improving prognostic accuracy, individualized therapies, and screening efforts.

Sex differences in β-amyloid accumulation in 3xTg-AD mice: role of neonatal sex steroid hormone exposure.

PubMed

Carroll, Jenna C; Rosario, Emily R; Kreimer, Sara; Villamagna, Angela; Gentzschein, Elisabet; Stanczyk, Frank Z; Pike, Christian J

2010-12-17

The risk of Alzheimer's disease (AD) is higher in women than in men, a sex difference that likely results from the effects of sex steroid hormones. To investigate this relationship, we first compared progression of β-amyloid (Aβ) pathology in male and female triple transgenic (3xTg-AD) mice. We found that female 3xTg-AD mice exhibit significantly greater Aβ burden and larger behavioral deficits than age-matched males. Next, we evaluated how the organizational effects of sex steroid hormones during postnatal development may affect adult vulnerability to Aβ pathology. We observed that male 3xTg-AD mice demasculinized during early development exhibit significantly increased Aβ accumulation in adulthood. In contrast, female mice defeminized during early development exhibit a more male-like pattern of Aβ pathology in adulthood. Taken together, these results demonstrate significant sex differences in pathology in 3xTg-AD mice and suggest that these differences may be mediated by organizational actions of sex steroid hormones during development. Copyright © 2010 Elsevier B.V. All rights reserved.

The emergence of sex differences in personality traits in early adolescence: A cross-sectional, cross-cultural study.

PubMed

De Bolle, Marleen; De Fruyt, Filip; McCrae, Robert R; Löckenhoff, Corinna E; Costa, Paul T; Aguilar-Vafaie, Maria E; Ahn, Chang-Kyu; Ahn, Hyun-Nie; Alcalay, Lidia; Allik, Jüri; Avdeyeva, Tatyana V; Bratko, Denis; Brunner-Sciarra, Marina; Cain, Thomas R; Chan, Wayne; Chittcharat, Niyada; Crawford, Jarret T; Fehr, Ryan; Ficková, Emília; Gelfand, Michele J; Graf, Sylvie; Gülgöz, Sami; Hřebíčková, Martina; Jussim, Lee; Klinkosz, Waldemar; Knežević, Goran; Leibovich de Figueroa, Nora; Lima, Margarida P; Martin, Thomas A; Marušić, Iris; Mastor, Khairul Anwar; Nakazato, Katsuharu; Nansubuga, Florence; Porrata, Jose; Purić, Danka; Realo, Anu; Reátegui, Norma; Rolland, Jean-Pierre; Schmidt, Vanina; Sekowski, Andrzej; Shakespeare-Finch, Jane; Shimonaka, Yoshiko; Simonetti, Franco; Siuta, Jerzy; Szmigielska, Barbara; Vanno, Vitanya; Wang, Lei; Yik, Michelle; Terracciano, Antonio

2015-01-01

Although large international studies have found consistent patterns of sex differences in personality traits among adults (i.e., women scoring higher on most facets), less is known about cross-cultural sex differences in adolescent personality and the role of culture and age in shaping them. The present study examines the NEO Personality Inventory-3 (McCrae, Costa, & Martin, 2005) informant ratings of adolescents from 23 cultures (N = 4,850), and investigates culture and age as sources of variability in sex differences of adolescents' personality. The effect for Neuroticism (with females scoring higher than males) begins to take on its adult form around age 14. Girls score higher on Openness to Experience and Conscientiousness at all ages between 12 and 17 years. A more complex pattern emerges for Extraversion and Agreeableness, although by age 17, sex differences for these traits are highly similar to those observed in adulthood. Cross-sectional data suggest that (a) with advancing age, sex differences found in adolescents increasingly converge toward adult patterns with respect to both direction and magnitude; (b) girls display sex-typed personality traits at an earlier age than boys; and (c) the emergence of sex differences was similar across cultures. Practical implications of the present findings are discussed. (PsycINFO Database Record (c) 2015 APA, all rights reserved). (PsycINFO Database Record (c) 2015 APA, all rights reserved).

Sex differences in jealousy: a population-based twin study in Sweden.

PubMed

Walum, Hasse; Larsson, Henrik; Westberg, Lars; Lichtenstein, Paul; Magnusson, Patrik K E

2013-10-01

According to the theory of evolved sex differences in jealousy, the challenge for women to ensure paternal investment increased their jealousy response to emotional infidelity, whereas paternal uncertainty exerted selective pressures that shaped men to become more distressed by sexual infidelity. Several studies have investigated whether the effect of these sexually dimorphic selection pressures can be detected in contemporary human populations, with conflicting results. To date, no genetically informed studies of sex differences in jealousy have been conducted. We used data from the Screening Across the Lifespan of Twins Younger (SALTY) sample, containing information concerning self-rated jealousy from 3,197 complete twin pairs collected by the Swedish Twin Registry. Intra-class correlations and structural equation models were used to assess the genetic influence on jealousy and to investigate sex differences at genetic level. We saw a highly significant sex effect on the relationship between infidelity types, indicating that men, relative to women, reported greater jealousy in response to sexual infidelity than in response to emotional infidelity. The twin models revealed significant heritabilities for both sexual (32%) and emotional (26%) jealousy. The heritabilities were of a similar magnitude in both sexes, and no qualitative sex differences could be detected. We show for the first time that variance in jealousy is to some extent explained by genetic factors. Even though our results from the mean value analyses are in line with the theory of evolved sex differences in jealousy, we could not identify any sex differences on a genetic level.

Ultrasonic vocalizations in golden hamsters (Mesocricetus auratus) reveal modest sex differences and nonlinear signals of sexual motivation.

PubMed

Fernández-Vargas, Marcela; Johnston, Robert E

2015-01-01

Vocal signaling is one of many behaviors that animals perform during social interactions. Vocalizations produced by both sexes before mating can communicate sex, identity and condition of the caller. Adult golden hamsters produce ultrasonic vocalizations (USV) after intersexual contact. To determine whether these vocalizations are sexually dimorphic, we analyzed the vocal repertoire for sex differences in: 1) calling rates, 2) composition (structural complexity, call types and nonlinear phenomena) and 3) acoustic structure. In addition, we examined it for individual variation in the calls. The vocal repertoire was mainly composed of 1-note simple calls and at least half of them presented some degree of deterministic chaos. The prevalence of this nonlinear phenomenon was confirmed by low values of harmonic-to-noise ratio for most calls. We found modest sexual differences between repertoires. Males were more likely than females to produce tonal and less chaotic calls, as well as call types with frequency jumps. Multivariate analysis of the acoustic features of 1-note simple calls revealed significant sex differences in the second axis represented mostly by entropy and bandwidth parameters. Male calls showed lower entropy and inter-quartile bandwidth than female calls. Because the variation of acoustic structure within individuals was higher than among individuals, USV could not be reliably assigned to the correct individual. Interestingly, however, this high variability, augmented by the prevalence of chaos and frequency jumps, could be the result of increased vocal effort. Hamsters motivated to produce high calling rates also produced longer calls of broader bandwidth. Thus, the sex differences found could be the result of different sex preferences but also of a sex difference in calling motivation or condition. We suggest that variable and complex USV may have been selected to increase responsiveness of a potential mate by communicating sexual arousal and preventing habituation to the caller.

Of Meat and Men: Sex Differences in Implicit and Explicit Attitudes Toward Meat.

PubMed

Love, Hamish J; Sulikowski, Danielle

2018-01-01

Modern attitudes to meat in both men and women reflect a strong meat-masculinity association. Sex differences in the relationship between meat and masculinity have not been previously explored. In the current study we used two IATs (implicit association tasks), a visual search task, and a questionnaire to measure implicit and explicit attitudes toward meat in men and women. Men exhibited stronger implicit associations between meat and healthiness than did women, but both sexes associated meat more strongly with 'healthy' than 'unhealthy' concepts. As 'healthy' was operationalized in the current study using terms such as "virile" and "powerful," this suggests that a meat-strength/power association may mediate the meat-masculinity link readily observed across western cultures. The sex difference was not related to explicit attitudes to meat, nor was it attributable to a variety of other factors, such as a generally more positive disposition toward meat in men than women. Men also exhibited an attention bias toward meats, compared to non-meat foods, while females exhibited more caution when searching for non-meat foods, compared to meat. These biases were not related to implicit attitudes, but did tend to increase with increasing hunger levels. Potential ultimate explanations for these differences, including sex differences in bio-physiological needs and receptivity to social signals are discussed.

Potential Reporting Bias in Neuroimaging Studies of Sex Differences.

PubMed

David, Sean P; Naudet, Florian; Laude, Jennifer; Radua, Joaquim; Fusar-Poli, Paolo; Chu, Isabella; Stefanick, Marcia L; Ioannidis, John P A

2018-04-17

Numerous functional magnetic resonance imaging (fMRI) studies have reported sex differences. To empirically evaluate for evidence of excessive significance bias in this literature, we searched for published fMRI studies of human brain to evaluate sex differences, regardless of the topic investigated, in Medline and Scopus over 10 years. We analyzed the prevalence of conclusions in favor of sex differences and the correlation between study sample sizes and number of significant foci identified. In the absence of bias, larger studies (better powered) should identify a larger number of significant foci. Across 179 papers, median sample size was n = 32 (interquartile range 23-47.5). A median of 5 foci related to sex differences were reported (interquartile range, 2-9.5). Few articles (n = 2) had titles focused on no differences or on similarities (n = 3) between sexes. Overall, 158 papers (88%) reached "positive" conclusions in their abstract and presented some foci related to sex differences. There was no statistically significant relationship between sample size and the number of foci (-0.048% increase for every 10 participants, p = 0.63). The extremely high prevalence of "positive" results and the lack of the expected relationship between sample size and the number of discovered foci reflect probable reporting bias and excess significance bias in this literature.

Sex differences in the influence of body mass index on anatomical architecture of brain networks.

PubMed

Gupta, A; Mayer, E A; Hamadani, K; Bhatt, R; Fling, C; Alaverdyan, M; Torgerson, C; Ashe-McNalley, C; Van Horn, J D; Naliboff, B; Tillisch, K; Sanmiguel, C P; Labus, J S

2017-08-01

The brain has a central role in regulating ingestive behavior in obesity. Analogous to addiction behaviors, an imbalance in the processing of rewarding and salient stimuli results in maladaptive eating behaviors that override homeostatic needs. We performed network analysis based on graph theory to examine the association between body mass index (BMI) and network measures of integrity, information flow and global communication (centrality) in reward, salience and sensorimotor regions and to identify sex-related differences in these parameters. Structural and diffusion tensor imaging were obtained in a sample of 124 individuals (61 males and 63 females). Graph theory was applied to calculate anatomical network properties (centrality) for regions of the reward, salience and sensorimotor networks. General linear models with linear contrasts were performed to test for BMI and sex-related differences in measures of centrality, while controlling for age. In both males and females, individuals with high BMI (obese and overweight) had greater anatomical centrality (greater connectivity) of reward (putamen) and salience (anterior insula) network regions. Sex differences were observed both in individuals with normal and elevated BMI. In individuals with high BMI, females compared to males showed greater centrality in reward (amygdala, hippocampus and nucleus accumbens) and salience (anterior mid-cingulate cortex) regions, while males compared to females had greater centrality in reward (putamen) and sensorimotor (posterior insula) regions. In individuals with increased BMI, reward, salience and sensorimotor network regions are susceptible to topological restructuring in a sex-related manner. These findings highlight the influence of these regions on integrative processing of food-related stimuli and increased ingestive behavior in obesity, or in the influence of hedonic ingestion on brain topological restructuring. The observed sex differences emphasize the importance of considering sex differences in obesity pathophysiology.

Sex Differences in the Influence of Body Mass Index on Anatomical Architecture of Brain Networks

PubMed Central

Gupta, Arpana; Mayer, Emeran A.; Hamadani, Kareem; Bhatt, Ravi; Fling, Connor; Alaverdyan, Mher; Torgenson, Carinna; Ashe-McNalley, Cody; Van Horn, John D; Naliboff, Bruce; Tillisch, Kirsten; Sanmiguel, Claudia P.; Labus, Jennifer S.

2017-01-01

Background/Objective The brain plays a central role in regulating ingestive behavior in obesity. Analogous to addiction behaviors, an imbalance in the processing of rewarding and salient stimuli results in maladaptive eating behaviors that override homeostatic needs. We performed network analysis based on graph theory to examine the association between body mass index (BMI) and network measures of integrity, information flow, and global communication (centrality) in reward, salience and sensorimotor regions, and to identify sex-related differences in these parameters. Subjects/Methods Structural and diffusion tensor imaging were obtained in a sample of 124 individuals (61 males and 63 females). Graph theory was applied to calculate anatomical network properties (centrality) for regions of the reward, salience, and sensorimotor networks. General linear models with linear contrasts were performed to test for BMI and sex-related differences in measures of centrality, while controlling for age. Results In both males and females, individuals with high BMI (obese and overweight) had greater anatomical centrality (greater connectivity) of reward (putamen) and salience (anterior insula) network regions. Sex differences were observed both in individuals with normal and elevated BMI. In individuals with high BMI, females compared to males showed greater centrality in reward (amygdala, hippocampus, nucleus accumbens) and salience (anterior mid cingulate cortex) regions, while males compared to females had greater centrality in reward (putamen) and sensorimotor (posterior insula) regions. Conclusions In individuals with increased BMI, reward, salience, and sensorimotor network regions are susceptible to topological restructuring in a sex related manner. These findings highlight the influence of these regions on integrative processing of food-related stimuli and increased ingestive behavior in obesity, or in the influence of hedonic ingestion on brain topological restructuring. The observed sex differences emphasize the importance of considering sex differences in obesity pathophysiology. PMID:28360430

Sex Differences in Cannabis Use and Effects: A Cross-Sectional Survey of Cannabis Users.

PubMed

Cuttler, Carrie; Mischley, Laurie K; Sexton, Michelle

2016-01-01

Introduction: Despite known sex differences in the endocannabinoid system of animals, little attention has been paid to sex differences in human's cannabis use patterns and effects. The purpose of the present study was to examine sex differences in cannabis use patterns and effects in a large sample of recreational and medical cannabis users. Methods: A large sample ( n =2374) of cannabis users completed an anonymous, online survey that assessed their cannabis use practices and experiences, including the short-term acute effects of cannabis and withdrawal effects. A subsample of 1418 medical cannabis users further indicated the medical conditions for which they use cannabis and its perceived efficacy. Results: The results indicated that men reported using cannabis more frequently and in higher quantities than did women. Men were more likely to report using joints/blunts, vaporizers, and concentrates, while women were more likely to report using pipes and oral administration. Men were more likely than women to report increased appetite, improved memory, enthusiasm, altered time perception, and increased musicality when high, while women were more likely than men to report loss of appetite and desire to clean when high. Men were more likely than women to report insomnia and vivid dreams during periods of withdrawal, while women were more likely than men to report nausea and anxiety as withdrawal symptoms. Sex differences in the conditions for which medical cannabis is used, and its efficacy, were trivial. Conclusions: These results may be used to focus research on biological and psychosocial mechanisms underlying cannabis-related sex differences, to inform clinicians treating individuals with cannabis use disorders, and to inform cannabis consumers, clinicians, and policymakers about the risks and benefits of cannabis for both sexes.

Sex Differences in Cannabis Use and Effects: A Cross-Sectional Survey of Cannabis Users

PubMed Central

Cuttler, Carrie; Mischley, Laurie K.; Sexton, Michelle

2016-01-01

Abstract Introduction: Despite known sex differences in the endocannabinoid system of animals, little attention has been paid to sex differences in human's cannabis use patterns and effects. The purpose of the present study was to examine sex differences in cannabis use patterns and effects in a large sample of recreational and medical cannabis users. Methods: A large sample (n=2374) of cannabis users completed an anonymous, online survey that assessed their cannabis use practices and experiences, including the short-term acute effects of cannabis and withdrawal effects. A subsample of 1418 medical cannabis users further indicated the medical conditions for which they use cannabis and its perceived efficacy. Results: The results indicated that men reported using cannabis more frequently and in higher quantities than did women. Men were more likely to report using joints/blunts, vaporizers, and concentrates, while women were more likely to report using pipes and oral administration. Men were more likely than women to report increased appetite, improved memory, enthusiasm, altered time perception, and increased musicality when high, while women were more likely than men to report loss of appetite and desire to clean when high. Men were more likely than women to report insomnia and vivid dreams during periods of withdrawal, while women were more likely than men to report nausea and anxiety as withdrawal symptoms. Sex differences in the conditions for which medical cannabis is used, and its efficacy, were trivial. Conclusions: These results may be used to focus research on biological and psychosocial mechanisms underlying cannabis-related sex differences, to inform clinicians treating individuals with cannabis use disorders, and to inform cannabis consumers, clinicians, and policymakers about the risks and benefits of cannabis for both sexes. PMID:28861492

Sex differences in the response to emotional distraction: an event-related fMRI investigation.

PubMed

Iordan, Alexandru D; Dolcos, Sanda; Denkova, Ekaterina; Dolcos, Florin

2013-03-01

Evidence has suggested that women have greater emotional reactivity than men. However, it is unclear whether these differences in basic emotional responses are also associated with differences in emotional distractibility, and what the neural mechanisms that implement differences in emotional distractibility between women and men are. Functional MRI recording was used in conjunction with a working memory (WM) task, with emotional distraction (angry faces) presented during the interval between the memoranda and the probes. First, we found an increased impact of emotional distraction among women in trials associated with high-confidence responses, in the context of overall similar WM performance in women and men. Second, women showed increased sensitivity to emotional distraction in brain areas associated with "hot" emotional processing, whereas men showed increased sensitivity in areas associated with "cold" executive processing, in the context of overall similar patterns of response to emotional distraction in women and men. Third, a sex-related dorsal-ventral hemispheric dissociation emerged in the lateral PFC related to coping with emotional distraction, with women showing a positive correlation with WM performance in left ventral PFC, and men showing similar effects in the right dorsal PFC. In addition to extending to men results that have previously been reported in women, by showing that both sexes engage mechanisms that are similar overall in response to emotional distraction, the present study identifies sex differences in both the response to and coping with emotional distraction. These results have implications for understanding sex differences in the susceptibility to affective disorders, in which basic emotional responses, emotional distractibility, and coping abilities are altered.

Sex differences in the adolescent brain and body: Findings from the saguenay youth study.

PubMed

Paus, Tomáš; Wong, Angelita Pui-Yee; Syme, Catriona; Pausova, Zdenka

2017-01-02

This Mini-Review describes sex differences in 66 quantitative characteristics of the brain and body measured in a community-based sample of 1,024 adolescents 12-18 years of age, members of the Saguenay Youth Study. Using an extensive phenotyping protocol, we have obtained measures in a number of domains, including brain structure, cognition, mental health, substance use, body composition, metabolism, cardiovascular reactivity, and life style. For each measure, we provide estimates of effect size (Cohen's d) and sex-specific correlations with age (Pearson R). In total 59 of the 66 characteristics showed sex differences (at a nominal P < 0.05), with small (32), medium-sized (13), and large (11) effects. Some, but not all, of these sex differences increase during adolescence; this appears to be the case mostly for anatomical and physiological measures. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Sex differences in attention to disgust facial expressions.

PubMed

Kraines, Morganne A; Kelberer, Lucas J A; Wells, Tony T

2017-12-01

Research demonstrates that women experience disgust more readily and with more intensity than men. The experience of disgust is associated with increased attention to disgust-related stimuli, but no prior study has examined sex differences in attention to disgust facial expressions. We hypothesised that women, compared to men, would demonstrate increased attention to disgust facial expressions. Participants (n = 172) completed an eye tracking task to measure visual attention to emotional facial expressions. Results indicated that women spent more time attending to disgust facial expressions compared to men. Unexpectedly, we found that men spent significantly more time attending to neutral faces compared to women. The findings indicate that women's increased experience of emotional disgust also extends to attention to disgust facial stimuli. These findings may help to explain sex differences in the experience of disgust and in diagnoses of anxiety disorders in which disgust plays an important role.

Sex differences in lizard escape decisions vary with latitude, but not sexual dimorphism.

PubMed

Samia, Diogo S M; Møller, Anders Pape; Blumstein, Daniel T; Stankowich, Theodore; Cooper, William E

2015-04-22

Sexual selection is a powerful evolutionary mechanism that has shaped the physiology, behaviour and morphology of the sexes to the extent that it can reduce viability while promoting traits that enhance reproductive success. Predation is one of the underlying mechanisms accounting for viability costs of sexual displays. Therefore, we should expect that individuals of the two sexes adjust their anti-predator behaviour in response to changes in predation risk. We conducted a meta-analysis of 28 studies (42 species) of sex differences in risk-taking behaviour in lizards and tested whether these differences could be explained by sexual dichromatism, by sexual size dimorphism or by latitude. Latitude was the best predictor of the interspecific heterogeneity in sex-specific behaviour. Males did not change their escape behaviour with latitude, whereas females had increasingly reduced wariness at higher latitudes. We hypothesize that this sex difference in risk-taking behaviour is linked to sex-specific environmental constraints that more strongly affect the reproductive effort of females than males. This novel latitudinal effect on sex-specific anti-predator behaviour has important implications for responses to climate change and for the relative roles of natural and sexual selection in different species. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Sex-role identification and violent victimization: gender differences in the role of masculinity.

PubMed

Daigle, Leah E; Mummert, Sadie J

2014-01-01

Although sex-role identification has been found to be associated with crime and delinquency, the link between sex-role identification and violent victimization has remained largely unexplored. Using the Add Health data, this study examines sex-role identification and its relationship to violent victimization. The findings suggest that masculinity increases the risk of violent victimization for males, but does not for females. Other differences in risk factors across gender were also found. These findings indicate that masculinity is an important construct in understanding the complexity of why some persons are violently victimized and others are not.

Effects of sex and proficiency in second language processing as revealed by a large-scale fNIRS study of school-aged children.

PubMed

Sugiura, Lisa; Ojima, Shiro; Matsuba-Kurita, Hiroko; Dan, Ippeita; Tsuzuki, Daisuke; Katura, Takusige; Hagiwara, Hiroko

2015-10-01

Previous neuroimaging studies in adults have revealed that first and second languages (L1/L2) share similar neural substrates, and that proficiency is a major determinant of the neural organization of L2 in the lexical-semantic and syntactic domains. However, little is known about neural substrates of children in the phonological domain, or about sex differences. Here, we conducted a large-scale study (n = 484) of school-aged children using functional near-infrared spectroscopy and a word repetition task, which requires a great extent of phonological processing. We investigated cortical activation during word processing, emphasizing sex differences, to clarify similarities and differences between L1 and L2, and proficiency-related differences during early L2 learning. L1 and L2 shared similar neural substrates with decreased activation in L2 compared to L1 in the posterior superior/middle temporal and angular/supramarginal gyri for both sexes. Significant sex differences were found in cortical activation within language areas during high-frequency word but not during low-frequency word processing. During high-frequency word processing, widely distributed areas including the angular/supramarginal gyri were activated in boys, while more restricted areas, excluding the angular/supramarginal gyri were activated in girls. Significant sex differences were also found in L2 proficiency-related activation: activation significantly increased with proficiency in boys, whereas no proficiency-related differences were found in girls. Importantly, cortical sex differences emerged with proficiency. Based on previous research, the present results indicate that sex differences are acquired or enlarged during language development through different cognitive strategies between sexes, possibly reflecting their different memory functions. © 2015 Wiley Periodicals, Inc.

Gender differences in endocrine responses to posture and 7 days of 6 deg head down bed rest

NASA Technical Reports Server (NTRS)

Vernikos, J.; Dallman, M. F.; Keil, L. C.; Ohara, D.; Convertino, V. A.

1993-01-01

Endocrine regulation of fluids and electrolytes during seven days of 6 deg head down bed rest (HDBR) was compared in male (n = 8) and, for the first time, female (n = 8) volunteers. The subjects' responses to quiet standing for 2 hr before and after HDBR were also tested. In both sexes, diuresis and natriuresis were evident during the first 2-3 days of HDBR, resulting in a marked increase in the urinary Na/K ratio and significant Na retention on reambulation. After the first day of HDBR, plasma renin activity (PRA) was increased relative to aldosterone, plasma volume was decreased, and the renal response to aldosterone appeared to be appropriate. Circulating levels of arginine vasopressin (AVP), cortisol, and ACTH were unchanged during HDBR. Plasma testosterone decreased slightly on day 2 of HDBR in males. The ratio of AM ACTH to cortisol was lower in females than in males because ACTH was lower in females. Urinary cortisol increased and remained elevated throughout the HDBR in males only. There were no gender differences in the responses to 7 day HDBR, except those in the pituitary-adrenal system; those differences appeared unrelated to the postural change. The provocative cardiovascular test of quiet standing before and after bed rest revealed both sex differences and effects of HDBR. There were significant sex differences in cardiovascular responses to standing, before and after HDBR. Females had greater PRA and aldosterone responses to standing before bedrest and larger aldosterone responses to standing after HDBR than males. Cardiovascular responses to standing before and after bedrest differed markedly: arterial pressure and heart rates increased with standing before HDBR, by contrast, arterial pressure decreased, with greater increases in heart rates after HDBR. In both sexes, all hormonal responses to standing were greater after HDBR. The results show clearly that similar responses to standing as well as to HDBR occur in both sexes, but that females exhibit greater PRA and aldosterone responses than males.

A Review of the Differences in Developmental, Psychiatric, and Medical Endophenotypes Between Males and Females with Autism Spectrum Disorder

PubMed Central

Rubenstein, Eric; Wiggins, Lisa D.; Lee, Li-Ching

2015-01-01

Autism spectrum disorder (ASD) is over four times more prevalent in males compared to females. Increased understanding of sex differences in ASD endophenotypes could add insight into possible etiologies and the assessment and management of the disorder. Consequently, the purpose of this review is to describe current literature regarding sex differences in the developmental, psychiatric, and medical endophenotypes of ASD in order to illustrate current knowledge and areas in need of further research. Our review found that repetitive behaviors and restricted interests are more common in males than females with ASD. Intellectual disability is more common in females than males with ASD. Attention to detail may be more common in males than females with ASD and epilepsy may be more common in females than males with ASD, although limited research in these areas prevent definitive conclusions from being drawn. There does not appear to be a sex difference in other developmental, psychiatric, and medical symptoms associated with ASD, or the research was contradictory or too sparse to establish a sex difference. Our review is unique in that it offers detailed discussion of sex differences in three major endophenotypes of ASD. Further research is needed to better understand why sex differences exist in certain ASD traits and to evaluate whether phenotypic sex differences are related to different pathways of development, assessment, and treatment of the disorder. PMID:26146472

Gestational dietary protein is associated with sex specific decrease in blood flow, fetal heart growth and post-natal blood pressure of progeny.

PubMed

Hernandez-Medrano, Juan H; Copping, Katrina J; Hoare, Andrew; Wapanaar, Wendela; Grivell, Rosalie; Kuchel, Tim; Miguel-Pacheco, Giuliana; McMillen, I Caroline; Rodgers, Raymond J; Perry, Viv E A

2015-01-01

The incidence of adverse pregnancy outcomes is higher in pregnancies where the fetus is male. Sex specific differences in feto-placental perfusion indices identified by Doppler assessment have recently been associated with placental insufficiency and fetal growth restriction. This study aims to investigate sex specific differences in placental perfusion and to correlate these changes with fetal growth. It represents the largest comprehensive study under field conditions of uterine hemodynamics in a monotocous species, with a similar long gestation period to the human. Primiparous 14 mo heifers in Australia (n=360) and UK (n=180) were either individually or group fed, respectively, diets with differing protein content (18, 14, 10 or 7% crude protein (CP)) from 60 d prior to 98 days post conception (dpc). Fetuses and placentae were excised at 98 dpc (n = 48). Fetal development an median uterine artery blood flow were assessed monthly from 36 dpc until term using B-mode and Doppler ultrasonography. MUA blood flow to the male feto-placental unit increased in early pregnancy associated with increased fetal growth. Protein restriction before and shortly after conception (-60 d up to 23 dpc) increased MUA diameter and indices of velocity during late pregnancy, reduced fetal heart weight in the female fetus and increased heart rate at birth, but decreased systolic blood pressure at six months of age. Sex specific differences both in feto-placental Doppler perfusion indices and response of these indices to dietary perturbations were observed. Further, maternal diet affected development of fetal cardiovascular system associated with altered fetal haemodynamics in utero, with such effects having a sex bias. The results from this study provide further insight into the gender specific circulatory differences present in the fetal period and developing cardiovascular system.

Sex differences in stress regulation of arousal and cognition.

PubMed

Bangasser, Debra A; Eck, Samantha R; Telenson, Alexander M; Salvatore, Madeleine

2018-04-01

There are sex differences in the prevalence and presentation of many psychiatric disorders. For example, posttraumatic stress disorder (PTSD) and major depression are more common in women than men, and women with these disorders present with more hyperarousal symptoms than men. In contrast, attention deficit hyperactivity disorder (ADHD) and schizophrenia are more common in men than women, and men with these disorders have increased cognitive deficits compared to women. A shared feature of the aforementioned psychiatric disorders is the contribution of stressful events to their onset and/or severity. Here we propose that sex differences in stress responses bias females towards hyperarousal and males towards cognitive deficits. Evidence from clinical and preclinical studies is detailed. We also describe underlying neurobiological mechanisms. For example, sex differences in stress receptor signaling and trafficking in the locus coeruleus-arousal center are detailed. In learning circuits, evidence for sex differences in dendritic morphology is provided. Finally, we describe how evaluating sex-specific mechanisms for responding to stress in female and male rodents can lead to better treatments for stress-related psychiatric disorders. Copyright © 2017 Elsevier Inc. All rights reserved.

The influences of sex and posture on joint energetics during drop landings.

PubMed

Norcross, M F; Shultz, S J; Weinhold, P S; Lewek, M D; Padua, D A; Blackburn, J T

2015-04-01

Previous observations suggest that females utilize a more erect initial landing posture than males with sex differences in landing posture possibly related to sex-specific energy absorption (EA) strategies. However, sex-specific EA strategies have only been observed when accompanied by sex differences in initial landing posture. This study (a) investigated the potential existence of sex-specific EA strategies; and (b) determined the influences of sex and initial landing posture on the biomechanical determinants of EA. The landing biomechanics of 80 subjects were recorded during drop landings in Preferred, Flexed, and Erect conditions. No sex differences in joint EA were identified after controlling for initial landing posture. Males and females exhibited greater ankle EA during Erect vs Flexed landings with this increase driven by 12% greater ankle velocity, but no change in ankle extensor moment. No differences in hip and knee EA were observed between conditions. However, to achieve similar knee EA, subjects used 7% greater mean knee extensor moment but 9% less knee angular velocity during Flexed landings. The results suggest that sex-specific EA strategies do not exist, and that the magnitude of knee joint EA can be maintained by modulating the relative contributions of joint moment and angular velocity to EA. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

EFFECT OF DELAYED AUDITORY FEEDBACK, SPEECH RATE, AND SEX ON SPEECH PRODUCTION.

PubMed

Stuart, Andrew; Kalinowski, Joseph

2015-06-01

Perturbations in Delayed Auditory Feedback (DAF) and speech rate were examined as sources of disruptions in speech between men and women. Fluent adult men (n = 16) and women (n = 16) spoke at a normal and an imposed fast rate of speech with 0, 25, 50, 100, and 200 msec. DAF. The syllable rate significantly increased when participants were instructed to speak at a fast rate, and the syllable rate decreased with increasing DAF delays. Men's speech rate was significantly faster during the fast speech rate condition with a 200 msec. DAF. Disfluencies increased with increasing DAF delay. Significantly more disfluency occurred at delays of 25 and 50 msec. at the fast rate condition, while more disfluency occurred at 100 and 200 msec. in normal rate conditions. Men and women did not display differences in the number of disfluencies. These findings demonstrate sex differences in susceptibility to perturbations in DAF and speech rate suggesting feedforward/feedback subsystems that monitor vocalizations may be different between sexes.

Sex-Related Differences in the Effects of the Mediterranean Diet on Glucose and Insulin Homeostasis

PubMed Central

Bédard, Alexandra; Corneau, Louise; Lamarche, Benoît; Dodin, Sylvie; Lemieux, Simone

2014-01-01

Objective. To document sex differences in the impact of the Mediterranean diet (MedDiet) on glucose/insulin homeostasis and to verify whether these sex-related effects were associated with changes in nonesterified fatty acids (NEFA). Methods. All foods were provided to 38 men and 32 premenopausal women (24–53 y) during 4 weeks. Variables were measured during a 180 min OGTT before and after the MedDiet. Results. A sex-by-time interaction for plasma insulin iAUC was found (men: −17.8%, P = 0.02; women: +9.4%, P = 0.63; P for sex-by-time interaction = 0.005). A sex-by-time interaction was also observed for insulin sensitivity (Cederholm index, P = 0.03), for which only men experienced improvements (men: +8.1%, P = 0.047; women: −5.9%, P = 0.94). No sex difference was observed for glucose and C-peptide responses. Trends toward a decrease in NEFA AUC (P = 0.06) and an increase in NEFA suppression rate (P = 0.06) were noted, with no sex difference. Changes in NEFA were not associated with change in insulin sensitivity. Conclusions. Results suggest that the more favorable changes in glucose/insulin homeostasis observed in men compared to women in response to the MedDiet are not explained by sex differences in NEFA response. This clinical trial is registered with clinicaltrials.gov NCT01293344. PMID:25371817

Sex differences in lung cancer survival: long-term trends using population-based cancer registry data in Osaka, Japan.

PubMed

Kinoshita, Fukuaki Lee; Ito, Yuri; Morishima, Toshitaka; Miyashiro, Isao; Nakayama, Tomio

2017-09-01

Several studies of sex differences in lung cancer survival have been reported. However, large-size population-based studies based on long-term observation are scarce. We investigated long-term trends in sex differences in lung cancer survival using population-based cancer registry data from Osaka, Japan. We analyzed 79 330 cases from the Osaka Cancer Registry (OCR) diagnosed between 1975 and 2007. We calculated 5-year relative survival in the six periods (1975-1980, 1981-1986, 1987-1992, 1993-1997, 1998-2002 and 2003-2007). To estimate the trends in sex differences in lung cancer survival throughout the study period, we applied a multivariate excess hazard model to control for confounders. The proportion of adenocarcinoma (ADC) and 5-year relative relative survival have increased for both sexes. Sex differences in lung cancer survival have widened over the period, especially in ADC and since the late 1990s. The excess hazard ratio of death within 5 years for males was 1.19 (95% CI: 1.16-1.21), adjusting for period at diagnosis, histologic type, stage, age group and treatment. We reported that females have better prognosis in lung cancer than males and the sex differences in lung cancer survival have become wider in Osaka, Japan. This can be partly explained by the sex differences in the proportions of histologic type and stage. Further studies considering other factors that influence sex differences in lung cancer survival are needed. © The Author 2017. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

Observer influences on pain: an experimental series examining same-sex and opposite-sex friends, strangers, and romantic partners.

PubMed

Edwards, Rhiannon; Eccleston, Christopher; Keogh, Edmund

2017-05-01

Despite the well-documented sex and gender differences, little is known about the relative impact of male-female social interactions on pain. Three experiments were conducted to investigate whether the type of interpersonal relationship men and women have with an observer affects how they respond to experimental pain. Study 1 recruited friends and strangers, study 2 examined the effects of same- and opposite-sex friends, whereas study 3 investigated the differences between opposite-sex friends and opposite-sex romantic partners. One hundred forty-four dyads were recruited (48 in each study). One person from each dyad completed 2 pain tasks, whereas the other person observed in silence. Overall, the presence of another person resulted in an increase in pain threshold and tolerance on the cold-pressor task and algometer. The sex status of the dyads also had a role, but only within the friendship groups. In particular, male friends had the most pronounced effect on men's pain, increasing pain tolerance. We suggest that the presence of an observer, their sex, and the nature of the participant-observer relationship all influence how pain is reported. Further research should focus on dyadic relationships, and their influence on how men and women report and communicate pain in specific contexts.

Does biological sex impact intestinal epithelial injury, small intestine permeability, gastrointestinal symptoms and systemic cytokine profile in response to exertional-heat stress?

PubMed

Snipe, Rhiannon M J; Costa, Ricardo J S

2018-05-23

This study aimed to determine the influence of biological sex on intestinal injury, permeability, gastrointestinal symptoms, and systemic cytokine profile in response to exertional-heat stress. Male (n= 13) and eumenorrheic female (n= 11) endurance runners completed 2 h running at 60% V̇O 2max in 35°C. Blood samples were collected pre- and post-exercise and during recovery to determine plasma intestinal fatty-acid binding protein (I-FABP) and systemic cytokine profile. Urinary lactulose:L-rhamnose ratio was used to determine small intestine permeability. I-FABP increased 479% pre- to post-exercise (p< 0.001), with no difference between sexes (p= 0.432). No differences between sexes were observed for small intestine permeability (p= 0.808), gut discomfort, total, upper- and lower-gastrointestinal symptoms. However, males reported significantly higher flatulence (p= 0.049) and abdominal stitch (p= 0.025) compared to females. IL-6, IL-8, IL-10 and IL-1ra increased pre- to post-exercise (p< 0.05), with no difference between sexes. However, IL-1β increased post-exercise in males only, and was higher in males compared to females (p= 0.044). Findings suggest that when females are in the follicular phase of the menstrual cycle, biological sex has no effect on intestinal epithelial injury and permeability, and minimal effect on gastrointestinal symptoms and systemic cytokine profile in response to exertional-heat stress.

Sex Differences in Context Fear Generalization and Recruitment of Hippocampus and Amygdala during Retrieval

PubMed Central

Keiser, Ashley A; Turnbull, Lacie M; Darian, Mara A; Feldman, Dana E; Song, Iris; Tronson, Natalie C

2017-01-01

Anxiety disorders are commonly associated with increased generalization of fear from a stress- or trauma-associated environment to a neutral context or environment. Differences in context-associated memory in males and females may contribute to increased susceptibility to anxiety disorders in women. Here we examined sex differences in context fear generalization and its neural correlates. We observed stronger context fear conditioning and more generalization of fear to a similar context in females than males. In addition, context preexposure increased fear conditioning in males and decreased generalization in females. Accordingly, males showed stronger cFos activity in dorsal hippocampus during memory retrieval and context generalization, whereas females showed preferential recruitment of basal amygdala. Together, these findings are consistent with previous research showing that hippocampal activity correlates with reduced context fear generalization. Differential competition between hippocampus and amygdala-dependent processes may thus contribute to sex differences in retrieval of context fear and greater generalization of fear-associated memory. PMID:27577601

Sex Differences in Genetic and Environmental Influences on Longitudinal Change in Functional Ability in Late Adulthood.

PubMed

Finkel, Deborah; Ernsth-Bravell, Marie; Pedersen, Nancy L

2015-09-01

To determine the extent to which genetic and environmental factors contribute to individual and gender differences in aging of functional ability. Twenty assessments of functional ability are collected as part of the longitudinal Swedish Adoption/Twin Study of Aging from 859 twins aged 50-88 at the first wave. Participants completed up to 6 assessments covering a 19-year period. Factor analysis was used to create 3 factors: flexibility, fine motor skills, and balance. Latent growth curve analysis demonstrated increasing disability and variability after age 70. For flexibility, results indicated significant sex differences in mean change trajectories but no sex differences in components of variance. No sex differences were found for fine motor movement. For balance, there were no sex differences in mean change trajectories; however, there was significant genetic variance for changes in balance in women after age 70 but not for men. Although idiosyncratic environmental influences account for a large part of increasing variance, correlated and shared rearing environmental effects were also evident. Thus, both microenvironmental (individual) and macroenvironmental (family and cultural) effects, as well as genetic factors, affect maintenance of functional ability in late adulthood. © The Author 2014. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Sex Steroid Signaling: Implications for Lung Diseases

PubMed Central

Sathish, Venkatachalem; Martin, Yvette N.; Prakash, Y.S.

2015-01-01

There is increasing recognition that the sex hormones (estrogen, progesterone, and testosterone) have biological and pathophysiological actions in peripheral, non-reproductive organs, including the lung. Clinically, sex differences in the incidence, morbidity and mortality of lung diseases such as asthma, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, lung cancer and pulmonary hypertension have been noted, although intrinsic sex differences vs. the roles of sex steroids are still not well-understood. Accordingly, it becomes important to ask the following questions: 1) Which sex steroids are involved? 2) How do they affect different components of the lung under normal circumstances? 3) How does sex steroid signaling change in or contribute to lung disease, and in this regard, are sex steroids detrimental or beneficial? As our understanding of sex steroid signaling in the lung improves, it is important to consider whether such information can be used to develop new therapeutic strategies to target lung diseases, perhaps in both sexes or in a sex-specific manner. In this review, we focus on the basics of sex steroid signaling, and the current state of knowledge regarding how they influence structure and function of specific lung components across the life span and in the context of some important lung diseases. We then summarize the potential for sex steroids as useful biomarkers and therapeutic targets in these lung diseases as a basis for future translational research in the area of gender and individualized medicine. PMID:25595323

Neurovascular control of blood pressure is influenced by aging, sex, and sex hormones.

PubMed

Baker, Sarah E; Limberg, Jacqueline K; Ranadive, Sushant M; Joyner, Michael J

2016-12-01

In this review, we highlight that the relationship between muscle sympathetic nerve activity (MSNA) and mean arterial pressure is complex, differs by sex, and changes with age. In young men there is an inverse relationship between MSNA and cardiac output where high MSNA is compensated for by low cardiac output. This inverse relationship is not seen in older men. In young women sympathetic vasoconstriction is offset by β-adrenoreceptor mediated vasodilation, limiting the ability of young women to maintain blood pressure in response to orthostatic stress. However, β-mediated dilation in women is attenuated with age, leading to unopposed α-adrenergic vasoconstriction and a rise in the direct transduction of MSNA into increases in blood pressure. We propose that these changes with age and menopausal status are major contributing factors in the increased prevalence of hypertension in older women. In addition to aging, we highlight that changes in sex hormones in young women (across the menstrual cycle, with oral contraceptive use, or with pregnancy) influence MSNA and the transduction of MSNA into increases in blood pressure. It is likely that the β-adrenergic receptors and/or changes in baroreflex sensitivity play a large role in these sex differences and changes with alterations in sex hormones. Copyright © 2016 the American Physiological Society.

Partner violence, power and gender differences in South African adolescents’ HIV/STI behaviors

PubMed Central

TEITELMAN, Anne M.; JEMMOTT, John B.; BELLAMY, Scarlett L.; ICARD, Larry D.; O'LEARY, Ann; HEEREN, G. Anita; NGWANE, Zolani; RATCLIFFE, Sarah J.

2016-01-01

Objectives Low relationship power and victimization by intimate partner violence (IPV) have been linked to HIV risks among adult females and adolescent girls. This article examines associations of IPV and relationship power with sexual-risk behaviors and whether the associations differ by gender among South African adolescents. Methods Sexual-risk behaviors (multiple partners in past 3 months; condom use at last sex), IPV, and relationship power were collected from 786 sexually experienced adolescents (mean age = 16.9) in Eastern Cape Province, South Africa during the 54-month follow-up of a HIV/STI risk-reduction intervention trial. Logistic regression examined associations of sexual-risk behaviors with IPV and relationship power and whether the associations differed by gender. Results Adolescent boys were less likely to report condom use at last sex (p=.001) and more likely to report multiple partners (p< .001). A Gender x IPV interaction (p=.002) revealed that as IPV victimization increased, self-reported condom use at last sex decreased among girls, but increased among boys. A Gender x Relationship Power interaction (p=.004) indicated that as relationship power increased, self-reported condom use at last sex increased among girls, but decreased among boys. A Gender x IPV interaction (p=.004) indicated that as IPV victimization increased, self-reports of having multiple partners increased among boys, but not among girls. As relationship power increased, self-reports of having multiple partners decreased irrespective of gender. Conclusions HIV risk-reduction interventions and policies should address gender differences in sexual-risk consequences of IPV and relationship power among adolescents and promote gender equity. PMID:27111184

Sex differences in normal age trajectories of functional brain networks.

PubMed

Scheinost, Dustin; Finn, Emily S; Tokoglu, Fuyuze; Shen, Xilin; Papademetris, Xenophon; Hampson, Michelle; Constable, R Todd

2015-04-01

Resting-state functional magnetic resonance image (rs-fMRI) is increasingly used to study functional brain networks. Nevertheless, variability in these networks due to factors such as sex and aging is not fully understood. This study explored sex differences in normal age trajectories of resting-state networks (RSNs) using a novel voxel-wise measure of functional connectivity, the intrinsic connectivity distribution (ICD). Males and females showed differential patterns of changing connectivity in large-scale RSNs during normal aging from early adulthood to late middle-age. In some networks, such as the default-mode network, males and females both showed decreases in connectivity with age, albeit at different rates. In other networks, such as the fronto-parietal network, males and females showed divergent connectivity trajectories with age. Main effects of sex and age were found in many of the same regions showing sex-related differences in aging. Finally, these sex differences in aging trajectories were robust to choice of preprocessing strategy, such as global signal regression. Our findings resolve some discrepancies in the literature, especially with respect to the trajectory of connectivity in the default mode, which can be explained by our observed interactions between sex and aging. Overall, results indicate that RSNs show different aging trajectories for males and females. Characterizing effects of sex and age on RSNs are critical first steps in understanding the functional organization of the human brain. © 2014 Wiley Periodicals, Inc.

Early-Life Telomere Dynamics Differ between the Sexes and Predict Growth in the Barn Swallow (Hirundo rustica)

PubMed Central

Parolini, Marco; Romano, Andrea; Khoriauli, Lela; Nergadze, Solomon G.; Caprioli, Manuela; Rubolini, Diego; Santagostino, Marco; Saino, Nicola; Giulotto, Elena

2015-01-01

Telomeres are conserved DNA-protein structures at the termini of eukaryotic chromosomes which contribute to maintenance of genome integrity, and their shortening leads to cell senescence, with negative consequences for organismal functions. Because telomere erosion is influenced by extrinsic and endogenous factors, telomere dynamics may provide a mechanistic basis for evolutionary and physiological trade-offs. Yet, knowledge of fundamental aspects of telomere biology under natural selection regimes, including sex- and context-dependent variation in early-life, and the covariation between telomere dynamics and growth, is scant. In this study of barn swallows (Hirundo rustica) we investigated the sex-dependent telomere erosion during nestling period, and the covariation between relative telomere length and body and plumage growth. Finally, we tested whether any covariation between growth traits and relative telomere length depends on the social environment, as influenced by sibling sex ratio. Relative telomere length declined on average over the period of nestling maximal growth rate (between 7 and 16 days of age) and differently covaried with initial relative telomere length in either sex. The frequency distribution of changes in relative telomere length was bimodal, with most nestlings decreasing and some increasing relative telomere length, but none of the offspring traits predicted the a posteriori identified group to which individual nestlings belonged. Tail and wing length increased with relative telomere length, but more steeply in males than females, and this relationship held both at the within- and among-broods levels. Moreover, the increase in plumage phenotypic values was steeper when the sex ratio of an individual’s siblings was female-biased. Our study provides evidence for telomere shortening during early life according to subtly different dynamics in either sex. Furthermore, it shows that the positive covariation between growth and relative telomere length depends on sex as well as social environment, in terms of sibling sex ratio. PMID:26565632

Immunohistochemical localization of serotonin in the brain during natural sex change in the hermaphroditic goby Lythrypnus dalli.

PubMed

Lorenzi, Varenka; Grober, Matthew S

2012-02-01

The neurotransmitter serotonin (5-HT) may play a central role in the inhibition of socially regulated sex change in fish because of its known modulation of both aggressive and reproductive behavior. This is the first study to use immunohistochemical techniques to examine the morphometry of serotonergic neurons at different times during sex change. Using a model species wherein sex change is socially regulated via agonistic social interactions (the bluebanded goby, Lythrypnus dalli), we sampled brains of males and females with different social status, and of females at different times during sex change. Consistent with previous studies on other teleosts, immunoreactive neurons were found in the posterior periventricular nucleus (NPPv), the nucleus of the lateral recess (NRL), the nucleus of the posterior recess (NRP) and in the raphe nucleus. We measured the total area of NPPv, NRL, NRP, and the number and mean cell area of serotonergic neurons in the raphe nucleus. There was no significant difference in any of the brain regions between males, females or sex changing fish, but there was a slight increase in the number of dorsal raphe neurons in the brain of sex changers 2h after male removal. The results show that in L. dalli the serotonergic system does not present any morphological sex and status differences, nor any dramatic modifications during sex change. These data, together with previous results, do not support the hypothesis that serotonin inhibits socially regulated sex change. Copyright © 2011 Elsevier Inc. All rights reserved.

Great ape origins of personality maturation and sex differences: a study of orangutans and chimpanzees.

PubMed

Weiss, Alexander; King, James E

2015-04-01

Human personality development evinces increased emotional stability, prosocial tendencies, and responsibility. One hypothesis offered to explain this pattern is Social-Investment Theory, which posits that culturally defined social roles, including marriage and employment, are responsible for the increased maturity. Alternatively, Five-Factor Theory emphasizes the role of biological factors, such as those governing physical development, which may predate the emergence of humans. Five-Factor Theory, unlike Social-Investment Theory, predicts that all or some of the human personality developmental trends should be present in great apes, our closest evolutionary relatives. To test this prediction and to better understand the evolutionary origins of sex differences, we examined age and sex differences in the chimpanzee and orangutan personality domains Extraversion, Dominance, Neuroticism, and Agreeableness. We also examined the Activity and Gregariousness facets of Extraversion and the orangutan Intellect domain. Extraversion and Neuroticism declined across age groups in both species, in common with humans. A significant interaction indicated that Agreeableness declined in orangutans but increased in chimpanzees, as it does in humans, though this may reflect differences in how Agreeableness was defined in each species. Significant interactions indicated that male chimpanzees, unlike male orangutans, displayed higher Neuroticism scores than females and maintained higher levels of Activity and Dominance into old age than female chimpanzees, male orangutans, and female orangutans. Personality-age correlations were comparable across orangutans and chimpanzees and were similar to those reported in human studies. Sex differences were stronger in chimpanzees than in humans or orangutans. These findings support Five-Factor Theory, suggest the role of gene-culture coevolution in shaping personality development, and suggest that sex differences evolved independently in different species. (c) 2015 APA, all rights reserved).

Sex differences in physiological response to the combination of stress and smoking.

PubMed

Kotlyar, Michael; Thuras, Paul; Hatsukami, Dorothy K; al'Absi, Mustafa

2017-08-01

Stressful situations are among the most commonly cited smoking triggers. Smoking and stress exposure each individually increase cardiovascular and hypothalamic-pituitary-adrenal measures with larger increases occurring when stress and smoking are combined. In this analysis, sex differences in the physiological response to the combination of stress and smoking are examined. Smokers (36 males; 34 females) completed a laboratory session in which systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR), plasma epinephrine (Epi), norepinephrine and cortisol concentrations were measured at rest, while smoking a cigarette, during a speech task occurring immediately after smoking and at several time-points following the stressor. Significant period by sex effects were observed for HR, SBP, DBP and Epi but not for cortisol or norepinephrine concentrations. For SBP (p=0.002), the increase between resting and speech were larger in men than in women, primarily due to a larger increase between smoking and speech occurring in men. A similar pattern was observed for DBP and Epi with a significantly larger Epi increase from smoking to speech observed in men than in women (p=0.016). A different pattern emerged for HR - the total increase was larger in women (p<0.001), due to a larger rest to smoking increase (p<0.001). In most measures therefore, overall increases were greater in men than women, primarily due to larger smoking to speech increases. Additional research is needed to determine the clinical implications of these results as they apply to sex difference in smoking cessation success rates and in the cardiovascular risks of smoking. Copyright © 2017 Elsevier B.V. All rights reserved.

Acute Stress Modulates Feedback Processing in Men and Women: Differential Effects on the Feedback-Related Negativity and Theta and Beta Power

PubMed Central

Banis, Stella; Geerligs, Linda; Lorist, Monicque M.

2014-01-01

Sex-specific prevalence rates in mental and physical disorders may be partly explained by sex differences in physiological stress responses. Neural networks that might be involved are those underlying feedback processing. Aim of the present EEG study was to investigate whether acute stress alters feedback processing, and whether stress effects differ between men and women. Male and female participants performed a gambling task, in a control and a stress condition. Stress was induced by exposing participants to a noise stressor. Brain activity was analyzed using both event-related potential and time-frequency analyses, measuring the feedback-related negativity (FRN) and feedback-related changes in theta and beta oscillatory power, respectively. While the FRN and feedback-related theta power were similarly affected by stress induction in both sexes, feedback-related beta power depended on the combination of stress induction condition and sex. FRN amplitude and theta power increases were smaller in the stress relative to the control condition in both sexes, demonstrating that acute noise stress impairs performance monitoring irrespective of sex. However, in the stress but not in the control condition, early lower beta-band power increases were larger for men than women, indicating that stress effects on feedback processing are partly sex-dependent. Our findings suggest that sex-specific effects on feedback processing may comprise a factor underlying sex-specific stress responses. PMID:24755943

Sex-specific differences in mitochondria biogenesis, morphology, respiratory function, and ROS homeostasis in young mouse heart and brain.

PubMed

Khalifa, Abdel Rahman M; Abdel-Rahman, Engy A; Mahmoud, Ali M; Ali, Mohamed H; Noureldin, Maha; Saber, Saber H; Mohsen, Mahmoud; Ali, Sameh S

2017-03-01

Sex-specific differences in mitochondrial function and free radical homeostasis are reported in the context of aging but not well-established in pathogeneses occurring early in life. Here, we examine if sex disparity in mitochondria function, morphology, and redox status starts early and hence can be implicated in sexual dimorphism in cardiac as well as neurological disorders prevalent at young age. Although mitochondrial activity in the heart did not significantly vary between sexes, female brain exhibited enhanced respiration and higher reserve capacity. This was associated with lower H 2 O 2 production in female cardiac and brain tissues. Using transmission electron microscopy, we found that the number of female cardiac mitochondria is moderately greater (117 ± 3%, P  = 0.049, N  = 4) than male's, which increased significantly for cortical mitochondria (134 ± 4%, P  = 0.001, N  = 4). However, male's cardiac mitochondria exhibited fragmented, circular, and smaller mitochondria relative to female's mitochondria, while no morphologic sex-dependent differences were observed in cortical mitochondria. No sex differences were detected in Nox2 and Nox4 proteins or O 2 -consuming/H 2 O 2 -producing activities in brain homogenate or synaptosomes. However, a strong trend of increased EPR-detected NOX superoxide in male synaptosomes hinted at higher superoxide dismutase activity in female brains, which was confirmed by two independent protocols. We also provide direct evidence that respiring mitochondria generally produce an order-of-magnitude lower reactive oxygen species (ROS) proportions than currently estimated. Our results indicate that sex differences in mitochondrial biogenesis, bioenergetics, and morphology may start at young age and that sex-dependent SOD capacity may be responsible for differences in ROS homeostasis in heart and brain. © 2017 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Sex Differences in the Impact of the Mediterranean Diet on LDL Particle Size Distribution and Oxidation

PubMed Central

Bédard, Alexandra; Corneau, Louise; Lamarche, Benoît; Dodin, Sylvie; Lemieux, Simone

2015-01-01

Sex differences have been previously highlighted in the cardioprotective effects of the Mediterranean diet (MedDiet). The objective of this study was to investigate whether sex differences also exist with regard to LDL particle size distribution and oxidation. Participants were 37 men and 32 premenopausal women (24–53 years) with slightly elevated LDL-C concentrations (3.4–4.9 mmol/L) or total cholesterol/HDL-C ≥5.0. Variables were measured before and after a four-week isoenergetic MedDiet. Sex differences were found in response to the MedDiet for the proportion of medium LDL (255–260 Å) (p for sex-by-time interaction = 0.01) and small, dense LDL (sdLDL; <255 Å) (trend; p for sex-by-time interaction = 0.06), men experiencing an increase in the proportion of medium LDL with a concomitant reduction in the proportion of sdLDL, while an opposite trend was observed in women. A sex difference was also noted for estimated cholesterol concentrations among sdLDL (p for sex-by-time interaction = 0.03), with only men experiencing a reduction in response to the MedDiet. The MedDiet marginally reduced oxidized LDL (oxLDL) concentrations (p = 0.07), with no sex difference. Results suggest that short-termconsumption of the MedDiet leads to a favorable redistribution of LDL subclasses from smaller to larger LDL only in men. These results highlight the importance of considering sex issues in cardiovascular benefits of the MedDiet. PMID:25988764

Sex-specific modulation of juvenile social play by vasopressin.

PubMed

Veenema, Alexa H; Bredewold, Remco; De Vries, Geert J

2013-11-01

Social play activities among juveniles are thought to contribute to the development of social and emotional skills in humans and animals. Conversely, social play deficits are observed in developmental neuropsychiatric disorders. Importantly, many of these disorders show sex differences in incidence, course of the disease, and severity of symptoms. We hypothesized that sex differences in the neural systems controlling social behavior can contribute to these differences. We therefore studied the involvement of the sexually dimorphic vasopressin and oxytocin systems, which have been implicated in these disorders, in juvenile social play behavior. Single-housed 5-week-old juvenile male and female rats were exposed in their home cage to an age-and sex-matched novel conspecific for 10 min, and social play behaviors were recorded. We found no consistent sex differences in duration or elements of social play in vehicle-treated rats. However, intracerebroventricular injection of the specific vasopressin 1a receptor (V1aR) antagonist (CH2)5Tyr(Me(2))AVP significantly reduced social play behaviors in males while increasing them in females. Intracerebroventricular injection of the specific oxytocin receptor antagonist des-Gly-NH2,d(CH2)5[Tyr(Me)(2),Thr(4)]OVT did not alter social play in either sex. To locate the effects of V1aR blockade on social play, we targeted the lateral septum, a sexually dimorphic brain region showing denser vasopressin fibers in males than in females and an abundant expression of V1aR in both sexes. Surprisingly, blockade of V1aR in the lateral septum increased social play behaviors in males, but decreased them in females. These findings suggest sex- and brain region-specific roles for vasopressin in the regulation of social play behavior in juvenile rats. Copyright © 2013 Elsevier Ltd. All rights reserved.

Sex-specific modulation of juvenile social play by vasopressin

PubMed Central

Veenema, Alexa H.; Bredewold, Remco; De Vries, Geert J.

2013-01-01

SUMMARY Social play activities among juveniles are thought to contribute to the development of social and emotional skills in humans and animals. Conversely, social play deficits are observed in developmental neuropsychiatric disorders. Importantly, many of these disorders show sex differences in incidence, course of the disease, and severity of symptoms. We hypothesized that sex differences in the neural systems controlling social behavior can contribute to these differences. We therefore studied the involvement of the sexually dimorphic vasopressin and oxytocin systems, which have been implicated in these disorders, in juvenile social play behavior. Single-housed 5-week-old juvenile male and female rats were exposed to an unknown age-and sex-matched conspecific for 10 min in their home cage and social play behaviors were recorded. We found no consistent sex differences in level or elements of social play in vehicle-treated rats. However, intracerebroventricular injection of the specific vasopressin 1a receptor (V1aR) antagonist (CH2)5Tyr(Me2) AVP significantly reduced social play behaviors in males, while increasing them in females. Intracerebroventricular injection of the specific oxytocin receptor antagonist des-Gly-NH2,d(CH2)5[Tyr(Me)2,Thr4]OVT did not alter social play in either sex. To locate the effects of V1aR blockade on social play, we targeted the lateral septum, a sexually dimorphic brain region showing denser vasopressin fibers in males than in females and abundant expression of V1aR in both sexes. Surprisingly, blockade of V1aR in the lateral septum increased social play behaviors in males, but decreased them in females. These findings suggest sex- and brain region-specific roles for vasopressin in the regulation of social play behavior in juvenile rats. PMID:23838102

Sex-related differences in lipid peroxidation and photoprotection in Pistacia lentiscus.

PubMed

Juvany, Marta; Müller, Maren; Pintó-Marijuan, Marta; Munné-Bosch, Sergi

2014-03-01

Sex-related differences in the response of dioecious plants to abiotic stress have been poorly studied to date. This work explored to what extent sex may affect plant stress responses in Pistacia lentiscus L. (Anacardiaceae), a tree well adapted to Mediterranean climatic conditions. It was hypothesized that a greater reproductive effort in females may increase oxidative stress in leaves, particularly when plants are exposed to abiotic stress. Measurements of oxidative stress markers throughout the year revealed increased lipid peroxidation in females, but only during the winter. Enhanced lipid peroxidation in females was associated with reduced photoprotection, as indicated by reduced tocopherol levels and nonphotochemical quenching (NPQ) of chlorophyll fluorescence. Enhanced lipid peroxidation in females was also observed at predawn, which was associated with increased lipoxygenase activity and reduced cytokinin levels. An analysis of the differences between reproductive (R) and nonreproductive (NR) shoots showed an enhanced photoprotective capacity in R shoots compared to NR shoots in females. This capacity was characterized by an increased NPQ and a better antioxidant protection (increased carotenoid and tocopherol levels per unit of chlorophyll) in R compared to NR shoots. It is concluded that (i) females exhibit higher lipid peroxidation in leaves than males, but only during the winter (when sex-related differences in reproductive effort are the highest), (ii) this is associated with a lower photoprotective capacity at midday, as well as enhanced lipoxygenase activity and reduced cytokinin levels at predawn, and (iii) photoprotection capacity is higher in R relative to NR shoots in females.

Sex-related differences in lipid peroxidation and photoprotection in Pistacia lentiscus

PubMed Central

Munné-Bosch, Sergi

2014-01-01

Sex-related differences in the response of dioecious plants to abiotic stress have been poorly studied to date. This work explored to what extent sex may affect plant stress responses in Pistacia lentiscus L. (Anacardiaceae), a tree well adapted to Mediterranean climatic conditions. It was hypothesized that a greater reproductive effort in females may increase oxidative stress in leaves, particularly when plants are exposed to abiotic stress. Measurements of oxidative stress markers throughout the year revealed increased lipid peroxidation in females, but only during the winter. Enhanced lipid peroxidation in females was associated with reduced photoprotection, as indicated by reduced tocopherol levels and nonphotochemical quenching (NPQ) of chlorophyll fluorescence. Enhanced lipid peroxidation in females was also observed at predawn, which was associated with increased lipoxygenase activity and reduced cytokinin levels. An analysis of the differences between reproductive (R) and nonreproductive (NR) shoots showed an enhanced photoprotective capacity in R shoots compared to NR shoots in females. This capacity was characterized by an increased NPQ and a better antioxidant protection (increased carotenoid and tocopherol levels per unit of chlorophyll) in R compared to NR shoots. It is concluded that (i) females exhibit higher lipid peroxidation in leaves than males, but only during the winter (when sex-related differences in reproductive effort are the highest), (ii) this is associated with a lower photoprotective capacity at midday, as well as enhanced lipoxygenase activity and reduced cytokinin levels at predawn, and (iii) photoprotection capacity is higher in R relative to NR shoots in females. PMID:24378602

Sex Differences in the Association between Stressor-Evoked Interleukin-6 Reactivity and C-Reactive Protein

PubMed Central

Lockwood, Kimberly G.; Marsland, Anna L.; Cohen, Sheldon; Gianaros, Peter J.

2016-01-01

Individuals differ consistently in the magnitude of their inflammatory responses to acute stressors, with females often showing larger responses than males. While the clinical significance of these individual differences remains unclear, it may be that greater inflammatory responses relate to increased systemic inflammation and thereby risk for chronic inflammatory disease. Here, we examined whether acute stressor-evoked interleukin (IL)-6 responses associate with resting levels of C-reactive protein (CRP), a marker of systemic inflammation, and whether this association differs by sex. Subjects were 57 healthy midlife adults (30–51 years; 33% female; 68% white). Blood was drawn before and 30-min after two mental stress tasks: a multisource interference task and a Stroop color word task. Hierarchical regressions controlling for age, sex, race, and BMI tested whether stressor-evoked IL-6 responses were associated with resting CRP and whether this association differed by sex. Results indicated that sex and stressor-evoked IL-6 responses interacted to predict CRP (ΔR2 = .08, B = −1.33, β = −.39, p = .02). In males, larger stressor-evoked IL-6 responses associated with higher CRP, whereas in females, stressor-evoked IL-6 responses showed a non-significant negative association with CRP. These findings indicate that inflammatory responses to acute stressors associate with resting levels of CRP; however, this association differs by sex. Previous literature suggests that there are sex differences in stressor-evoked IL-6 responses, but this is the first study to show sex differences in the relationship between acute inflammatory responses and systemic inflammation. The contribution of these sex differences to inflammatory disease risk warrants further investigation. PMID:27377561

Sex differences in the association between gray matter volume and verbal creativity.

PubMed

Shi, Baoguo; Xu, Li; Chen, Qunlin; Qiu, Jiang

2017-08-02

The explanation for why significant sex differences are found in creativity has become an increasingly important topic. The current study applied a cognitive neuroscience perspective and voxel-based morphometry to investigate the sex differences for the association between verbal creativity and gray matter volume (GMV) in a large sample of healthy adults from the Chinese Mainland (163 men and 193 women). Furthermore, we sought to determine which brain regions are responsible for these differences. Our behavioral results showed a significant sex difference. Specifically, women scored higher than men on originality. The voxel-based morphometry results indicated that the relationship between originality and GMV differed between men and women in the left temporo-occipital junction. Higher originality scores in women were associated with more GMV. In contrast, higher originality scores in men were related to less GMV. These findings suggest the left temporo-occipital junction GMV plays a unique role in the sex differences in verbal creativity because women usually surpass men in semantic processing, which is the major function of the left temporal region.

Sex Differences in Internalizing Problems during Adolescence in Autism Spectrum Disorder

ERIC Educational Resources Information Center

Oswald, Tasha M.; Winter-Messiers, Mary Ann; Gibson, Brandon; Schmidt, Alexandra M.; Herr, Cynthia M.; Solomon, Marjorie

2016-01-01

We hypothesized that the double hit conferred by sex and diagnosis increases the risk for internalizing disorders in adolescent females with autism spectrum disorder (ASD). In a sample of 32 adolescents with ASD and 32 controls, we examined the effects of sex, diagnostic factors, and developmental stages on depression and anxiety. A 3-way…

Corticotropin-releasing factor overexpression in mice abrogates sex differences in body weight, visceral fat, and food intake response to a fast and alters levels of feeding regulatory hormones.

PubMed

Wang, Lixin; Goebel-Stengel, Miriam; Yuan, Pu-Qing; Stengel, Andreas; Taché, Yvette

2017-01-01

Corticotropin-releasing factor overexpressing (CRF-OE) male mice showed an inhibited feeding response to a fast, and lower plasma acyl ghrelin and Fos expression in the arcuate nucleus compared to wild-type (WT) mice. We investigated whether hormones and hypothalamic feeding signals are impaired in CRF-OE mice and the influence of sex. Male and female CRF-OE mice and WT littermates (4-6 months old) fed ad libitum or overnight fasted were assessed for body, adrenal glands and perigonadal fat weights, food intake, plasma hormones, blood glucose, and mRNA hypothalamic signals. Under fed conditions, compared to WT, CRF-OE mice have increased adrenal glands and perigonadal fat weight, plasma corticosterone, leptin and insulin, and hypothalamic leptin receptor and decreased plasma acyl ghrelin. Compared to male, female WT mice have lower body and perigonadal fat and plasma leptin but higher adrenal glands weights. CRF-OE mice lost these sex differences except for the adrenals. Male CRF-OE and WT mice did not differ in hypothalamic expression of neuropeptide Y (NPY) and proopiomelanocortin (POMC), while female CRF-OE compared to female WT and male CRF-OE had higher NPY mRNA levels. After fasting, female WT mice lost more body weight and ate more food than male WT, while CRF-OE mice had reduced body weight loss and inhibited food intake without sex difference. In male WT mice, fasting reduced plasma insulin and leptin and increased acyl ghrelin and corticosterone while female WT showed only a rise in corticosterone. In CRF-OE mice, fasting reduced insulin while leptin, acyl ghrelin and corticosterone were unchanged with no sex difference. Fasting blood glucose was higher in CRF-OE with female > male. In WT mice, fasting increased hypothalamic NPY expression in both sexes and decreased POMC only in males, while in CRF-OE mice, NPY did not change, and POMC decreased in males and increased in females. These data indicate that CRF-OE mice have abnormal basal and fasting circulating hormones and hypothalamic feeding-related signals. CRF-OE also abolishes the sex difference in body weight, abdominal fat, and fasting-induced feeding and changes in plasma levels of leptin and acyl ghrelin.

Sex differences in the modulation of vasomotor sympathetic outflow during static handgrip exercise in healthy young humans

PubMed Central

Jarvis, Sara S.; VanGundy, Tiffany B.; Galbreath, M. Melyn; Shibata, Shigeki; Okazaki, Kazunobu; Reelick, Miriam F.; Levine, Benjamin D.

2011-01-01

Sex differences in sympathetic neural control during static exercise in humans are few and the findings are inconsistent. We hypothesized women would have an attenuated vasomotor sympathetic response to static exercise, which would be further reduced during the high sex hormone [midluteal (ML)] vs. the low hormone phase [early follicular (EF)]. We measured heart rate (HR), blood pressure (BP), and muscle sympathetic nerve activity (MSNA) in 11 women and 10 men during a cold pressor test (CPT) and static handgrip to fatigue with 2 min of postexercise circulatory arrest (PECA). HR increased during handgrip, reached its peak at fatigue, and was comparable between sexes. BP increased during handgrip and PECA where men had larger increases from baseline. Mean ± SD MSNA burst frequency (BF) during handgrip and PECA was lower in women (EF, P < 0.05), as was ΔMSNA-BF smaller (main effect, both P < 0.01). ΔTotal activity was higher in men at fatigue (EF: 632 ± 418 vs. ML: 598 ± 342 vs. men: 1,025 ± 416 a.u./min, P < 0.001 for EF and ML vs. men) and during PECA (EF: 354 ± 321 vs. ML: 341 ± 199 vs. men: 599 ± 327 a.u./min, P < 0.05 for EF and ML vs. men). During CPT, HR and MSNA responses were similar between sexes and hormone phases, confirming that central integration and the sympathetic efferent pathway was comparable between the sexes and across hormone phases. Women demonstrated a blunted metaboreflex, unaffected by sex hormones, which may be due to differences in muscle mass or fiber type and, therefore, metabolic stimulation of group IV afferents. PMID:21508291

Within-female plasticity in sex allocation is associated with a behavioural polyphenism in house wrens.

PubMed

Bowers, E K; Thompson, C F; Sakaluk, S K

2016-03-01

Sex allocation theory assumes individual plasticity in maternal strategies, but few studies have investigated within-individual changes across environments. In house wrens, differences between nests in the degree of hatching synchrony of eggs represent a behavioural polyphenism in females, and its expression varies with seasonal changes in the environment. Between-nest differences in hatching asynchrony also create different environments for offspring, and sons are more strongly affected than daughters by sibling competition when hatching occurs asynchronously over several days. Here, we examined variation in hatching asynchrony and sex allocation, and its consequences for offspring fitness. The number and condition of fledglings declined seasonally, and the frequency of asynchronous hatching increased. In broods hatched asynchronously, sons, which are over-represented in the earlier-laid eggs, were in better condition than daughters, which are over-represented in the later-laid eggs. Nonetheless, asynchronous broods were more productive later within seasons. The proportion of sons in asynchronous broods increased seasonally, whereas there was a seasonal increase in the production of daughters by mothers hatching their eggs synchronously, which was characterized by within-female changes in offspring sex and not by sex-biased mortality. As adults, sons from asynchronous broods were in better condition and produced more broods of their own than males from synchronous broods, and both males and females from asynchronous broods had higher lifetime reproductive success than those from synchronous broods. In conclusion, hatching patterns are under maternal control, representing distinct strategies for allocating offspring within broods, and are associated with offspring sex ratios and differences in offspring reproductive success. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

Sex-specific divergence for adaptations to dehydration stress in Drosophila kikkawai.

PubMed

Parkash, Ravi; Ranga, Poonam

2013-09-01

Several studies on diverse Drosophila species have reported higher desiccation resistance of females, but the physiological basis of such sex-specific differences has received less attention. We tested whether sex-specific differences in cuticular traits (melanic females and non-melanic males) of Drosophila kikkawai correspond with divergence in their water balance mechanisms. Our results are interesting in several respects. First, positive clinal variation in desiccation resistance was correlated with cuticular melanisation in females but with changes in cuticular lipid mass in males, despite a lack of differences between the sexes for the rate of water loss. Second, a comparative analysis of water budget showed that females of the northern population stored more body water as well as hemolymph content and exhibited greater dehydration tolerance than flies from the southern tropics. In contrast, we found no geographical variation in the males for water content and dehydration tolerance. Third, an ~10-fold increase in the rate of water loss after organic solvent treatment of male D. kikkawai suggested a role of cuticular lipids in cuticular transpiration, but had no effect in the females. Fourth, geographical differences in the storage of carbohydrate content (metabolic fuel) were observed in females but not in males. Interestingly, in females, the rate of utilization of carbohydrates did not vary geographically, but males from drier localities showed a 50% reduction compared with wetter localities. Thus, body melanisation, increased body water, hemolymph, carbohydrate content and greater dehydration tolerance confer greater desiccation resistance in females, but a reduced rate of water loss is the only possible mechanism to cope with drought stress in males. Finally, acclimated females showed a significant increase in drought resistance associated with higher trehalose content as well as dehydration tolerance, while males showed no acclimation response. Thus, sex-specific differences in desiccation resistance of D. kikkawai are associated with divergence in some water balance strategies, despite a lack of differences in the rate of water loss between the two sexes.

Will women outrun men in ultra-marathon road races from 50 km to 1,000 km?

PubMed

Zingg, Matthias Alexander; Karner-Rezek, Klaus; Rosemann, Thomas; Knechtle, Beat; Lepers, Romuald; Rüst, Christoph Alexander

2014-01-01

It has been assumed that women would be able to outrun men in ultra-marathon running. The present study investigated the sex differences in running speed in ultra-marathons held worldwide from 50 km to 1,000 km. Changes in running speeds and the sex differences in running speeds in the annual fastest finishers in 50 km, 100 km, 200 km and 1,000 km events held worldwide from 1969-2012 were analysed using linear, non-linear and multi-level regression analyses. For the annual fastest and the annual ten fastest finishers, running speeds increased non-linearly in 50 km and 100 km, but not in 200 km and 1,000 km where running speeds remained unchanged for the annual fastest. The sex differences decreased non-linearly in 50 km and 100 km, but not in 200 and 1,000 km where the sex difference remained unchanged for the annual fastest. For the fastest women and men ever, the sex difference in running speed was lowest in 100 km (5.0%) and highest in 50 km (15.4%). For the ten fastest women and men ever, the sex difference was lowest in 100 km (10.0 ± 3.0%) and highest in 200 km (27.3 ± 5.7%). For both the fastest (r(2) = 0.003, p = 0.82) and the ten fastest finishers ever (r(2) = 0.34, p = 0.41) in 50 km, 100 km, 200 km and 1,000 km, we found no correlation between sex difference in performance and running speed. To summarize, the sex differences in running speeds decreased non-linearly in 50 km and 100 km but remained unchanged in 200 km and 1,000 km, and the sex differences in running speeds showed no change with increasing length of the race distance. These findings suggest that it is very unlikely that women will ever outrun men in ultra-marathons held from 50 km to 100 km.

Age and sex variations in glucose tolerance and insulin responses: parallels with cardiovascular risk.

PubMed

Orchard, T J; Becker, D J; Kuller, L H; Wagener, D K; LaPorte, R E; Drash, A L

1982-02-01

The venous plasma glucose and insulin concentrations recorded during oral glucose tolerance testing of over 300 1st degree relatives (parents and siblings) of insulin dependent diabetics are presented. Men had higher glucose concentrations than women, the difference increasing with age, while insulin responses appeared greater in adolescent girls and young women than their male counterparts. The possible relationship between the different insulin responses in the two sexes and the sex difference in cardiovascular risk factors is discussed. It is suggested that the absence of a marked sex differential in heart disease mortality amongst diabetics may partly result from the loss by diabetic women of their greater insulin production relative to men in young adult life.

Sex hormones in Malay and Chinese men in Malaysia: are there age and race differences?

PubMed Central

Chin, Kok-Yong; Soelaiman, Ima-Nirwana; Mohamed, Isa Naina; Ahmad, Fairus; Ramli, Elvy Suhana Mohd; Aminuddin, Amilia; Ngah, Wan Zurinah Wan

2013-01-01

OBJECTIVES: Variations in the prevalence of sex-hormone-related diseases have been observed between Asian ethnic groups living in the same country; however, available data concerning their sex hormone levels are limited. The present study aimed to determine the influence of ethnicity and age on the sex hormone levels of Malay and Chinese men in Malaysia. METHODS: A total of 547 males of Malay and Chinese ethnicity residing in the Klang Valley Malaysia underwent a detailed screening, and their blood was collected for sex hormones analyses. RESULTS: Testosterone levels were normally distributed in the men (total, free and non-sex hormone-binding globulin (SHBG) bound fractions), and significant ethnic differences were observed (p<0.05); however, the effect size was small. In general, testosterone levels in males began to decline significantly after age 50. Significant ethnic differences in total, free and non-SHBG bound fraction estradiol levels were observed in the 20-29 and 50-59 age groups (p<0.05). The estradiol levels of Malay men decreased as they aged, but they increased for Chinese men starting at age 40. CONCLUSIONS: Small but significant differences in testosterone levels existed between Malay and Chinese males. Significant age and race differences existed in estradiol levels. These differences might contribute to the ethnic group differences in diseases related to sex hormones, which other studies have found in Malaysia. PMID:23525310

Sex hormones in Malay and Chinese men in Malaysia: are there age and race differences?

PubMed

Chin, Kok-Yong; Soelaiman, Ima-Nirwana; Mohamed, Isa Naina; Ahmad, Fairus; Ramli, Elvy Suhana Mohd; Aminuddin, Amilia; Ngah, Wan Zurinah Wan

2013-01-01

Variations in the prevalence of sex-hormone-related diseases have been observed between Asian ethnic groups living in the same country; however, available data concerning their sex hormone levels are limited. The present study aimed to determine the influence of ethnicity and age on the sex hormone levels of Malay and Chinese men in Malaysia. A total of 547 males of Malay and Chinese ethnicity residing in the Klang Valley Malaysia underwent a detailed screening, and their blood was collected for sex hormones analyses. Testosterone levels were normally distributed in the men (total, free and non-sex hormone-binding globulin (SHBG) bound fractions), and significant ethnic differences were observed (p<0.05); however, the effect size was small. In general, testosterone levels in males began to decline significantly after age 50. Significant ethnic differences in total, free and non-SHBG bound fraction estradiol levels were observed in the 20-29 and 50-59 age groups (p<0.05). The estradiol levels of Malay men decreased as they aged, but they increased for Chinese men starting at age 40. Small but significant differences in testosterone levels existed between Malay and Chinese males. Significant age and race differences existed in estradiol levels. These differences might contribute to the ethnic group differences in diseases related to sex hormones, which other studies have found in Malaysia.

Acute ethanol responses in Drosophila are sexually dimorphic

PubMed Central

Devineni, Anita V.; Heberlein, Ulrike

2012-01-01

In mammalian and insect models of ethanol intoxication, low doses of ethanol stimulate locomotor activity whereas high doses induce sedation. Sex differences in acute ethanol responses, which occur in humans, have not been characterized in Drosophila. In this study, we find that male flies show increased ethanol hyperactivity and greater resistance to ethanol sedation compared with females. We show that the sex determination gene transformer (tra) acts in the developing nervous system, likely through regulation of fruitless (fru), to at least partially mediate the sexual dimorphism in ethanol sedation. Although pharmacokinetic differences may contribute to the increased sedation sensitivity of females, neuronal tra expression regulates ethanol sedation independently of ethanol pharmacokinetics. We also show that acute activation of fru-expressing neurons affects ethanol sedation, further supporting a role for fru in regulating this behavior. Thus, we have characterized previously undescribed sex differences in behavioral responses to ethanol, and implicated fru in mediating a subset of these differences. PMID:23213244

Do differences in female sex hormone levels contribute to gastro-oesophageal reflux disease?

PubMed

Menon, Shyam; Prew, Sandra; Parkes, Gill; Evans, Stephanie; Smith, Lynne; Nightingale, Peter; Trudgill, Nigel

2013-07-01

Hormone replacement therapy is associated with both reflux symptoms and oesophagitis. During pregnancy, elevated sex hormones are thought to contribute to the high prevalence of reflux symptoms. Increased female sex hormone levels may thus contribute to the aetiology of gastro-oesophageal reflux disease (GORD). To determine if female sex hormone levels are associated with symptomatic acid reflux. Women with GORD symptoms undergoing oesophageal pH monitoring were prospectively recruited. 'Cases' and 'controls' were defined by normal and excess total acid exposure on pH monitoring and were age-matched and BMI-matched. Case and control groups were further stratified into premenopausal and postmenopausal groups. Demographic data were collected, body morphological parameters were measured and oestradiol, oestrone, progesterone and sex hormone-binding globulin were measured. One hundred and twenty-one women [mean age 52 (SD 11.6) years] were recruited and 104 [mean age 51 (SD 11.6) years] were matched for age and BMI. Increasing BMI, as expected, correlated with increasing acid exposure [premenopausal (r=0.404, P=0.02), postmenopausal (r=0.401, P=0.01)]. Increasing BMI also correlated with sex hormone levels [premenopausal oestradiol (r=0.52, P=0.004), postmenopausal oestrone (r=0.364, P=0.01)]. In premenopausal women, sex hormone binding globulin (r=-0.27, P=0.05) and testosterone (r=0.29, P=0.05) correlated with increasing acid exposure, but oestradiol fell just short of significance (r=0.26, P=0.06). However, on matching for BMI, no association between sex hormones and increased acid exposure on pH monitoring was found on multivariate logistic regression analysis. Female sex hormone levels do not appear to contribute to GORD, once adjustment is made for the influence of increasing BMI.

The XX sex chromosome complement in mice is associated with increased spontaneous lupus compared with XY.

PubMed

Sasidhar, Manda V; Itoh, Noriko; Gold, Stefan M; Lawson, Gregory W; Voskuhl, Rhonda R

2012-08-01

Many autoimmune diseases are characterised by a female predominance. This may be caused by sex hormones, sex chromosomes or both. This report uses a transgenic mouse model to investigate how sex chromosome complement, not confounded by differences in gonadal type, might contribute to lupus pathogenesis. Transgenic NZM2328 mice were created by deletion of the Sry gene from the Y chromosome, thereby separating genetic from gonadal sex. Survival, renal histopathology and markers of immune activation were compared in mice carrying the XX versus the XY(-) sex chromosome complement, with each genotype being ovary bearing. Mice with XX sex chromosome complement compared with XY(-) exhibited poorer survival rates and increased kidney pathology. Splenic T lymphocytes from XX mice demonstrated upregulated X-linked CD40 ligand expression and higher levels of activation markers ex vivo. Increased MMP, TGF and IL-13 production was found, while IL-2 was lower in XX mice. An accumulation of splenic follicular B cells and peritoneal marginal zone B cells was observed, coupled with upregulated costimulatory marker expression on B cells in XX mice. These data show that the XX sex chromosome complement, compared with XY(-), is associated with accelerated spontaneous lupus.

Sex-role reversal of a monogamous pipefish without higher potential reproductive rate in females.

PubMed

Sogabe, Atsushi; Yanagisawa, Yasunobu

2007-12-07

In monogamous animals, males are usually the predominant competitors for mates. However, a strictly monogamous pipefish Corythoichthys haematopterus exceptionally exhibits a reversed sex role. To understand why its sex role is reversed, we measured the adult sex ratio and the potential reproductive rate (PRR), two principal factors influencing the operational sex ratio (OSR), in a natural population of southern Japan. The adult sex ratio was biased towards females throughout the breeding season, but the PRR, which increased with water temperature, did not show sexual difference. We found that an alternative index of the OSR (Sf/Sm: sex ratio of 'time in') calculated from the monthly data was consistently biased towards females. The female-biased OSR associated with sex-role reversal has been reported in some polyandrous or promiscuous pipefish, but factors biasing the OSR differed between these pipefish and C. haematopterus. We concluded that the similar PRR between the sexes in C. haematopterus does not confer reproductive benefit of polygamous mating on either sex, resulting in strict monogamous mating, and its female-biased adult sex ratio promotes female-female competition for a mate, resulting in sex-role reversal.

Of Meat and Men: Sex Differences in Implicit and Explicit Attitudes Toward Meat

PubMed Central

Love, Hamish J.; Sulikowski, Danielle

2018-01-01

Modern attitudes to meat in both men and women reflect a strong meat-masculinity association. Sex differences in the relationship between meat and masculinity have not been previously explored. In the current study we used two IATs (implicit association tasks), a visual search task, and a questionnaire to measure implicit and explicit attitudes toward meat in men and women. Men exhibited stronger implicit associations between meat and healthiness than did women, but both sexes associated meat more strongly with ‘healthy’ than ‘unhealthy’ concepts. As ‘healthy’ was operationalized in the current study using terms such as “virile” and “powerful,” this suggests that a meat-strength/power association may mediate the meat-masculinity link readily observed across western cultures. The sex difference was not related to explicit attitudes to meat, nor was it attributable to a variety of other factors, such as a generally more positive disposition toward meat in men than women. Men also exhibited an attention bias toward meats, compared to non-meat foods, while females exhibited more caution when searching for non-meat foods, compared to meat. These biases were not related to implicit attitudes, but did tend to increase with increasing hunger levels. Potential ultimate explanations for these differences, including sex differences in bio-physiological needs and receptivity to social signals are discussed. PMID:29731733

Associations of Early and Late Gestational Weight Gain with Infant Birth Size.

PubMed

Wander, Pandora L; Sitlani, Colleen M; Badon, Sylvia E; Siscovick, David S; Williams, Michelle A; Enquobahrie, Daniel A

2015-11-01

Associations of gestational weight gain (GWG) during specific periods of pregnancy with infant birth size have been inconsistent. Infant sex-specific differences in these associations are unknown Information on GWG (kg) [total, early (<20 weeks gestation), and late (≥20 weeks gestation)] and indices of infant birth size including birthweight (BW), ponderal index (PI), crown-heel length (CHL), and head circumference (HC) was collected from 3,621 pregnant women. We calculated adjusted mean differences and 95 % confidence intervals (CIs) relating total, early and late GWG to infant birth size using multivariable linear regression procedures. We used stratified analyses and interaction terms to test whether associations differed by infant sex. One-kg increases in total, early or late GWG were associated with BW increases of 17.2 g (95 % CI 13.8-18.9), 14.1 g (95 % CI 10.3-18.0), and 21.0 g (95 % CI 16.7-25.4), respectively. Early GWG-BW and late GWG-BW associations were different (p = 0.026). Sex-stratified total GWG-BW associations were similar to overall results. There were sex-specific differences in early GWG-BW and late GWG-BW associations. Among females, early GWG-BW (12.0 g, 95 % CI 6.7-17.2) and late GWG-BW (24.2 g, 95 % CI 18.2-30.3) associations differed (p = 0.0042); the corresponding associations did not differ among males. Total, early, and late GWG were associated with CHL and HC, but not with PI. Associations did not differ for early or late GWG. For comparable GWG, late-GWG-related BW increase is greater than early-GWG-related BW increase, particularly among female infants.

The Relationship between Sexual Selection and Sexual Conflict

PubMed Central

Kokko, Hanna; Jennions, Michael D.

2014-01-01

Evolutionary conflicts of interest arise whenever genetically different individuals interact and their routes to fitness maximization differ. Sexual selection favors traits that increase an individual’s competitiveness to acquire mates and fertilizations. Sexual conflict occurs if an individual of sex A’s relative fitness would increase if it had a “tool” that could alter what an individual of sex B does (including the parental genes transferred), at a cost to B’s fitness. This definition clarifies several issues: Conflict is very common and, although it extends outside traits under sexual selection, sexual selection is a ready source of sexual conflict. Sexual conflict and sexual selection should not be presented as alternative explanations for trait evolution. Conflict is closely linked to the concept of a lag load, which is context-dependent and sex-specific. This makes it possible to ask if one sex can “win.” We expect higher population fitness if females win. PMID:25038050

Sex Differences in Stroke Therapies

PubMed Central

Sohrabji, Farida; Park, Min Jung; Mahnke, Amanda H

2016-01-01

Stroke is the 5th leading cause of death and acquired disability in aged populations. Women are disproportionally affected by stroke, having a higher incidence and worse outcomes than men. Numerous preclinical studies have discovered novel therapies for the treatment of stroke, but almost all of these were found to be unsuccessful in clinical trials. Despite known sex differences in occurrence and severity of stroke, few therapeutics, both preclinically and clinically, take into account possible sex differences in treatment. Reanalysis of data from the only currently FDA-approved stroke therapy, tPA, has shown to not only improve stroke outcomes for both sexes, but to also show sexual dimorphism by more robust improvement in stroke outcome in females. Experimental evidence supports the inclusion of sex as a variable in the study of a number of novel stroke drugs and therapies, including preclinical studies of anti-inflammatory drugs (minocycline), stimulators of cell survival (IGF-1), and inhibitors of cell death pathways (pharmacological inhibition of PARP-1, NO production, and caspase activation), as well as in current clinical trials of stem cell therapy and cortical stimulation. Overall, study design and analyses in clinical trials, as well as in preclinical studies, must include both sexes equally, consider possible sex differences in the analyses, and report the differences/similarities in more systemized/structured way to translate promising therapies to both sexes and increase stroke recovery. PMID:27870437

Testosterone-dependent sex differences in red blood cell hemolysis in storage, stress, and disease.

PubMed

Kanias, Tamir; Sinchar, Derek; Osei-Hwedieh, David; Baust, Jeffrey J; Jordan, Andrew; Zimring, James C; Waterman, Hayley R; de Wolski, Karen S; Acker, Jason P; Gladwin, Mark T

2016-10-01

Red blood cell (RBC) hemolysis represents an intrinsic mechanism for human vascular disease. Intravascular hemolysis releases hemoglobin and other metabolites that inhibit nitric oxide signaling and drive oxidative and inflammatory stress. Although these pathways are important in disease pathogenesis, genetic and population modifiers of hemolysis, including sex, have not been established. We studied sex differences in storage or stress-induced hemolysis in RBC units from the United States and Canada in 22 inbred mouse strains and in patients with sickle cell disease (SCD) using measures of hemolysis in 315 patients who had homozygous SS hemoglobin from the Walk-PHASST cohort. A mouse model also was used to evaluate posttransfusion recovery of stored RBCs, and gonadectomy was used to determine the mechanisms related to sex hormones. An analysis of predisposition to hemolysis based on sex revealed that male RBCs consistently exhibit increased susceptibility to hemolysis compared with females in response to routine cold storage, under osmotic or oxidative stress, after transfusion in mice, and in patients with SCD. The sex difference is intrinsic to the RBC and is not mediated by plasmatic factors or female sex hormones. Importantly, orchiectomy in mice improves RBC storage stability and posttransfusion recovery, whereas testosterone repletion therapy exacerbates hemolytic response to osmotic or oxidative stress. Our findings suggest that testosterone increases susceptibility to hemolysis across human diseases, suggesting that male sex may modulate clinical outcomes in blood storage and SCD and establishing a role for donor genetic variables in the viability of stored RBCs and in human hemolytic diseases. © 2016 AABB.

Sex-related differences and age of peak performance in breaststroke versus freestyle swimming

PubMed Central

2013-01-01

Background Sex-related differences in performance and in age of peak performance have been reported for freestyle swimming. However, little is known about the sex-related differences in other swimming styles. The aim of the present study was to compare performance and age of peak performance for elite men and women swimmers in breaststroke versus freestyle. Methods Race results were analyzed for swimmers at national ranked in the Swiss high score list (during 2006 through 2010) and for international swimmers who qualified for the finals of the FINA World Swimming Championships (during 2003 through 2011). Results The sex-related difference in swimming speed was significantly greater for freestyle than for breaststroke over 50 m, 100 m, and 200 m race distances for Swiss swimmers, but not for FINA finalists. The sex-related difference for both freestyle and breaststroke swimming speeds decreased significantly with increasing swimming distance for both groups. Race distance did not affect the age of peak performance by women in breaststroke, but age of peak performance was four years older for FINA women than for Swiss women. Men achieved peak swimming performance in breaststroke at younger ages for longer race distances, and the age of peak swimming performance was six years older for FINA men than for Swiss men. In freestyle swimming, race distance did not affect the age of peak swimming performance for Swiss women, but the age of peak swimming performance decreased with increasing race distance for Swiss men and for both sexes at the FINA World Championships. Conclusions Results of the present study indicate that (i) sex-related differences in swimming speed were greater for freestyle than for breaststroke for swimmers at national level, but not for swimmers at international level, and (ii) both female and male swimmers achieved peak swimming speeds at younger ages in breaststroke than in freestyle. Further studies are required to better understand differences between trends at national and international levels. PMID:24351335

Sex differences in verbal fluency during adolescence: a functional magnetic resonance imaging study in gender dysphoric and control boys and girls.

PubMed

Soleman, Remi S; Schagen, Sebastian E E; Veltman, Dick J; Kreukels, Baudewijntje P C; Cohen-Kettenis, Peggy T; Lambalk, Cornelis B; Wouters, Femke; Delemarre-van de Waal, Henriette A

2013-08-01

In the literature, verbal fluency (VF) is generally described as a female-favoring task. Although it is conceivable that this sex difference only evolves during adolescence or adulthood under influence of sex steroids, this has never been investigated in young adolescents. First, to assess sex differences in VF performance and regional brain activation in adolescents. Second, to determine if untreated transsexual adolescents differ from their sex of birth with regard to VF performance and regional brain activation. Twenty-five boys, 26 girls, 8 Male-to-Female transsexual adolescents (MtFs), and 14 Female-to-Male transsexual adolescents (FtMs) were tested in a cross-sectional study, while performing a phonetic and semantic VF task within an MRI scanner. Functional MRI response during VF task. Boys and girls produced similar amounts of words, but the group MtFs produced significantly more words in the phonetic condition compared to control boys, girls, and FtMs. During the semantic condition, no differences were found. With regard to brain activity, control boys showed more activation in the right Rolandic operculum, a small area adjacent to Broca's area, compared to girls. No significant differences in brain activity were found comparing transsexual adolescents, although sub-threshold activation was found in the right Rolandic operculum indicating a trendwise increase in activation from control girls to FtMs to MtFs to control boys. The better performance of MtFs is consistent with our expectation that MtFs perform better on female-favoring tasks. Moreover, they produced more words than girls and FtMs. Even though a trendwise linear increase in brain activity between the four groups only approached significance, it may indicate differences in individuals with gender identity disorder compared to their birth sex. Although our findings should thus be interpreted with caution, they suggest a biological basis for both transgender groups performing in-between the two sexes. © 2013 International Society for Sexual Medicine.

Sexual reproduction and population dynamics: the role of polygyny and demographic sex differences.

PubMed Central

Lindström, J; Kokko, H

1998-01-01

Most models of population dynamics do not take sexual reproduction into account (i.e., they do not consider the role of males). However, assumptions behind this practice--that no demographic sex differences exist and males are always abundant enough to fertilize all the females--are usually not justified in natural populations. On the contrary, demographic sex differences are common, especially in polygynous species. Previous models that consider sexual reproduction report a stabilizing effect through mixing of different genotypes, thus suggesting a decrease in the propensity for complex of dynamics in sexually reproducing populations. Here we show that considering the direct role of males in reproduction and density dependence leads to the conclusion that a two-sex model is not necessarily more stable compared with the corresponding one-sex model. Although solutions exist where sexual reproduction has a stabilizing effect even when no genotypic variability is included (primarily when associated with monogamy), factors like polygyny, sex differences in survival or density dependence, and possible alterations of the primary sex ratio (the Trivers-Willard mechanism), may enlarge the parametric region of complex dynamics. Sexual reproduction therefore does not necessarily increase the stability of population dynamics and can have destabilizing effects, at least in species with complicated mating systems and sexual dimorphism. PMID:9606132

Sex hormones in the modulation of irritable bowel syndrome.

PubMed

Mulak, Agata; Taché, Yvette; Larauche, Muriel

2014-03-14

Compelling evidence indicates sex and gender differences in epidemiology, symptomatology, pathophysiology, and treatment outcome in irritable bowel syndrome (IBS). Based on the female predominance as well as the correlation between IBS symptoms and hormonal status, several models have been proposed to examine the role of sex hormones in gastrointestinal (GI) function including differences in GI symptoms expression in distinct phases of the menstrual cycle, in pre- and post-menopausal women, during pregnancy, hormonal treatment or after oophorectomy. Sex hormones may influence peripheral and central regulatory mechanisms of the brain-gut axis involved in the pathophysiology of IBS contributing to the alterations in visceral sensitivity, motility, intestinal barrier function, and immune activation of intestinal mucosa. Sex differences in stress response of the hypothalamic-pituitary-adrenal axis and autonomic nervous system, neuroimmune interactions triggered by stress, as well as estrogen interactions with serotonin and corticotropin-releasing factor signaling systems are being increasingly recognized. A concept of "microgenderome" related to the potential role of sex hormone modulation of the gut microbiota is also emerging. Significant differences between IBS female and male patients regarding symptomatology and comorbidity with other chronic pain syndromes and psychiatric disorders, together with differences in efficacy of serotonergic medications in IBS patients confirm the necessity for more sex-tailored therapeutic approach in this disorder.

Prevalence and correlates of anal sex among secondary school students in Cape Town, South Africa.

PubMed

Ybarra, Michele; Price-Feeney, Myeshia; Mwaba, Kelvin

2018-07-01

Research efforts have overlooked anal sex as a risk factor for adolescents' acquisition of HIV despite the high rates of HIV among South African youth. Here, we report findings from a survey conducted in 2012 among secondary school youth, ages 16-24, in Cape Town. 937 adolescents completed a pencil-and-paper survey. Eleven and 31% of female and male youth, respectively, reported ever having anal sex. By comparison, 59% and 78% of female and male youth reported ever having vaginal sex. The percentage of youth reporting lifetime rates of anal sex increased with age: 32% of 20-to-24 year olds had anal sex compared to 16% of 16-to-17-year olds. When the sample was stratified by sex, this difference appeared to be driven by older male, but not female, sexual behavior. Despite noted differences in prevalence rates by sex, both boys and girls who had anal sex were more likely than their same-sex peers who had vaginal sex to report sexual coercion victimization and perpetration experiences and inconsistent condom use. Interestingly, some differences in HIV motivation, information, and behavioral skills were noted for youth who had vaginal sex versus youth who had never had sex; scores were largely similar for youth who had anal sex versus youth who had never had sex however. Together, these findings suggest that anal sex is not uncommon and may be an important marker for other HIV risk behaviors in at least one lower income South African community. Anal sex needs to be explicitly discussed in adolescent HIV prevention and healthy sexuality programing, incorporating age-relevant scenarios about negotiating condoms and other healthy relationship behaviors (e.g., refusing sex when it is not wanted).

Sex steroid signaling: implications for lung diseases.

PubMed

Sathish, Venkatachalem; Martin, Yvette N; Prakash, Y S

2015-06-01

There is increasing recognition that sex hormones (estrogen, progesterone, and testosterone) have biological and pathophysiological actions in peripheral, non-reproductive organs, including the lung. Clinically, sex differences in the incidence, morbidity and mortality of lung diseases such as asthma, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, lung cancer and pulmonary hypertension have been noted, although intrinsic sex differences vs. the roles of sex steroids are still not well-understood. Accordingly, it becomes important to ask the following questions: 1) Which sex steroids are involved? 2) How do they affect different components of the lung under normal circumstances? 3) How does sex steroid signaling change in or contribute to lung disease, and in this regard, are sex steroids detrimental or beneficial? As our understanding of sex steroid signaling in the lung improves, it is important to consider whether such information can be used to develop new therapeutic strategies to target lung diseases, perhaps in both sexes or in a sex-specific manner. In this review, we focus on the basics of sex steroid signaling, and the current state of knowledge regarding how they influence structure and function of specific lung components across the life span and in the context of some important lung diseases. We then summarize the potential for sex steroids as useful biomarkers and therapeutic targets in these lung diseases as a basis for future translational research in the area of gender and individualized medicine. Copyright © 2015 Elsevier Inc. All rights reserved.

"We are Two of the Lucky Ones": Experiences with Marriage and Wellbeing for Same-Sex Couples.

PubMed

Kennedy, Heather R; Dalla, Rochelle L; Dreesman, Steven

2018-01-01

Happy marriages provide protective health benefits, and social support is a key factor in this association. However, previous research indicates one of the greatest differences between same- and different-sex couples is less social support for same-sex couples. Our goal was to examine the extent to which formal markers of couple status (e.g., marriage) impact wellbeing among same-sex married partners. Using a mixed-methods approach, data were collected from 218 primarily White gay and lesbian individuals in the Midwest. Quantitative analysis revealed individuals in a prior formal union with a different-sex partner reported the lowest levels of sexuality specific social support and acceptance. Qualitative analysis revealed four primary impacts of marriage on support from family, friends, and co-workers: no change, increased support, decreased support, and a synthesis of mixed support. Three mechanisms prompting change in the family were identified and are presented.

Effect of sex on ethanol consumption and conditioned taste aversion in adolescent and adult rats.

PubMed

Schramm-Sapyta, Nicole L; Francis, Reynold; MacDonald, Andrea; Keistler, Colby; O'Neill, Lauren; Kuhn, Cynthia M

2014-04-01

Vulnerability to alcoholism is determined by many factors, including the balance of pleasurable vs. aversive alcohol-induced sensations: pleasurable sensations increase intake, while aversive sensations decrease it. Female sex and adolescent age are associated with lower sensitivity to intake-reducing effects and more rapid development of alcohol abuse. This study assessed voluntary drinking and the aversive effects of alcohol to determine whether these measures are inversely related across the sexes and development. Voluntary drinking of 20 % ethanol in an every-other-day (EOD) availability pattern and the dose-response relationship of ethanol conditioned taste aversion (CTA) were assessed in male and female adolescent and adult rats. CTA was sex specific in adult but not adolescent rats, with adult females exhibiting less aversion. Voluntary ethanol consumption varied according to age and individual differences but was not sex specific. Adolescents initially drank more than adults, exhibited greater day-to-day variation in consumption, were more susceptible to the alcohol deprivation effect, and took longer to establish individual differences in consumption patterns. These results show that the emergence of intake patterns differs between adolescents and adults. Adolescents as a group initiate drinking at high levels but decrease intake as they mature. A subset of adolescents maintained high drinking levels into adulthood. In contrast, most adults consumed at steady, low levels, but a small subset quickly established and maintained high-consumption patterns. Adolescents also showed marked deprivation-induced increases. Sex differences were not observed in EOD drinking during either adolescence or adulthood.

Effects of Estrogen in Gender-dependent Fetal Programming of Adult Cardiovascular Dysfunction.

PubMed

Chen, Zewen; Wang, Lei; Ke, Jun; Xiao, DaLiao

2018-03-01

Epidemiological studies and experimental studies have demonstrated that intrauterine adverse environment increases the risk of cardiovascular disease (CVD) in adulthood. However, whether an individual develops a cardiovascular dysfunctional phenotype may depend on genetic background, age, and sex. In this review, we summarize some of the recent experimental animal studies in the developmental programming of adult CVD with an emphasis on sex differences and the potential role of estrogen in mediating sexual dimorphism. Few epidemiological studies report the effect of sex on the developmental programming of CVD. However, numerous experimental animal studies have shown a sex difference in fetal programming of adult cardiovascular dysfunction. Most of the animal studies indicate that male offspring develop cardiovascular dysfunction and CVD in adulthood, whereas adult females appear to be protected. Estrogen is one of the key factors that contributes to the sex difference of adult CVD. Estrogen/its receptor (ER) may interact with the RAS system by changes of DNA methylation patterns at the target gene promoter, serve as an antioxidant to counteract the prenatal insults-induced heightened ROS, and function as an eNOS activator to increase vasodilation, resulting in the protection of female offspring from the development of hypertension and other CVDs. These studies suggest that estrogen/ER may contribute to sex differences in cardiovascular response to an adverse intrauterine environment and play a significant role in modulating the cardiovascular response in adulthood. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

A small-area ecologic study of myocardial infarction, neighborhood deprivation, and sex: a Bayesian modeling approach.

PubMed

Deguen, Séverine; Lalloue, Benoît; Bard, Denis; Havard, Sabrina; Arveiler, Dominique; Zmirou-Navier, Denis

2010-07-01

Socioeconomic inequalities in the risk of coronary heart disease (CHD) are well documented for men and women. CHD incidence is greater for men but its association with socioeconomic status is usually found to be stronger among women. We explored the sex-specific association between neighborhood deprivation level and the risk of myocardial infarction (MI) at a small-area scale. We studied 1193 myocardial infarction events in people aged 35-74 years in the Strasbourg metropolitan area, France (2000-2003). We used a deprivation index to assess the neighborhood deprivation level. To take into account spatial dependence and the variability of MI rates due to the small number of events, we used a hierarchical Bayesian modeling approach. We fitted hierarchical Bayesian models to estimate sex-specific relative and absolute MI risks across deprivation categories. We tested departure from additive joint effects of deprivation and sex. The risk of MI increased with the deprivation level for both sexes, but was higher for men for all deprivation classes. Relative rates increased along the deprivation scale more steadily for women and followed a different pattern: linear for men and nonlinear for women. Our data provide evidence of effect modification, with departure from an additive joint effect of deprivation and sex. We document sex differences in the socioeconomic gradient of MI risk in Strasbourg. Women appear more susceptible at levels of extreme deprivation; this result is not a chance finding, given the large difference in event rates between men and women.

The Number of X Chromosomes Causes Sex Differences in Adiposity in Mice

PubMed Central

Chen, Xuqi; McClusky, Rebecca; Chen, Jenny; Beaven, Simon W.; Tontonoz, Peter

2012-01-01

Sexual dimorphism in body weight, fat distribution, and metabolic disease has been attributed largely to differential effects of male and female gonadal hormones. Here, we report that the number of X chromosomes within cells also contributes to these sex differences. We employed a unique mouse model, known as the “four core genotypes,” to distinguish between effects of gonadal sex (testes or ovaries) and sex chromosomes (XX or XY). With this model, we produced gonadal male and female mice carrying XX or XY sex chromosome complements. Mice were gonadectomized to remove the acute effects of gonadal hormones and to uncover effects of sex chromosome complement on obesity. Mice with XX sex chromosomes (relative to XY), regardless of their type of gonad, had up to 2-fold increased adiposity and greater food intake during daylight hours, when mice are normally inactive. Mice with two X chromosomes also had accelerated weight gain on a high fat diet and developed fatty liver and elevated lipid and insulin levels. Further genetic studies with mice carrying XO and XXY chromosome complements revealed that the differences between XX and XY mice are attributable to dosage of the X chromosome, rather than effects of the Y chromosome. A subset of genes that escape X chromosome inactivation exhibited higher expression levels in adipose tissue and liver of XX compared to XY mice, and may contribute to the sex differences in obesity. Overall, our study is the first to identify sex chromosome complement, a factor distinguishing all male and female cells, as a cause of sex differences in obesity and metabolism. PMID:22589744

Gender differences and pain medication.

PubMed

Richardson, Jen; Holdcroft, Anita

2009-01-01

Subtle genetic and psychological variations are increasingly recognized to contribute to pain and analgesic efficacy and safety. The influence of sex on this relationship remains poorly understood, particularly in humans. The issue is complicated by the overlay of gender onto physical sex, and its associated stereotypes and expectations. Women appear to use more pain-relieving medications than men; however, it remains unclear whether these observations represent true differences in analgesic usage patterns, or reporting bias. Differences in analgesic efficacy relating to body composition, metabolism and hormonal profiles have been demonstrated. Psychological and social elements of gender have also been associated with altered pain experiences and analgesic use profiles, albeit with significant individual variations. Intra-group differences may ultimately prove more important than sex differences. Further research may unravel the various threads linking gender and sex effects on analgesia with the aim of individualizing analgesia to optimize pain relief.

School Leadership, Sex and Gender: Welcome to Difference

ERIC Educational Resources Information Center

Kruger, Meta L.

2008-01-01

The biological basis for differences between the sexes has become increasingly clear in recent years. The nature-nurture debate has made way for the view that the individual is a product of the interaction between genes and environment. For the world of school leadership this means that instead of arguing about them, we should acknowledge the…

Age, sex, and setting factors and labor force in athletic training.

PubMed

Kahanov, Leamor; Eberman, Lindsey E

2011-01-01

Occupation or occupational setting shifts might be occurring in the athletic training profession, and differences between sexes might exist; however, little evidence exists to confirm this supposition. To evaluate trends in male and female athletic training employment patterns in terms of age and occupational setting. Cross-sectional study. We requested demographic data from the National Athletic Trainers' Association (October 27, 2009) and obtained frequency totals of members by sex across the occupational life span by occupational setting. Our sample included 18 571 athletic trainers employed in the 3 largest classifications of occupational settings within the profession: college or university, clinical, and secondary school. We calculated frequencies and percentages to determine demographic and descriptive data. We analyzed the data using an analysis of variance to identify the differences between sexes across age and setting. We observed trends in occupational setting and sex across ages 22 to 67 years. We identified differences between sexes across the ages 22 to 67 years (F(1,18569) = 110818.080, P < .001, η(2) = .068) and across occupational settings (F(1,18569) = 61.908, P < .001, η(2) = .003), noting a marked decline in female athletic trainers in the workforce beginning around age 28 years and an increase in male athletic trainers in the secondary school setting beginning around their middle to late 40s. We observed differences at the intercept between setting and sex (F(1,18569) = 63529.344, P < .001, η(2) = .845), which were greater when observed across the ages (F(1,18569) = 23566787.642, P < .001, η(2) = .939). We identified differences between sexes across settings and ages in addition to an overall decrease in the workforce among all professionals. A marked decline in female athletic trainers occurred at age 28 years, yet the male population increased at the secondary school level, suggesting a setting shift. Burnout, fatigue, pay scale, and a misunderstanding of professional culture and job duties might influence the exodus or shift in athletic training.

Cross-cultural differences in physical aggression between partners: a social-role analysis.

PubMed

Archer, John

2006-01-01

In developed western nations, both sexes commit acts of physical aggression against their partners. Data from 16 nations showed that this pattern did not generalize to all nations. The magnitude and direction of the sex difference was highly correlated with national-level variations in gender empowerment and individualism-collectivism. As gender equality and individualism increased, the sex difference in partner violence moved in the direction of lesser female victimization and greater male victimization. A second analysis of 52 nations showed that 3 indexes of women's victimization were also inversely correlated with gender equality and individualism. Sexist attitudes and relative approval of wife beating were also associated with women's victimization rates, but general levels of violent crime were not. The findings are discussed in terms of a social role approach to variations in sex differences between cultures.

Differences in Movement Pattern and Detectability between Males and Females Influence How Common Sampling Methods Estimate Sex Ratio.

PubMed

Rodrigues, João Fabrício Mota; Coelho, Marco Túlio Pacheco

2016-01-01

Sampling the biodiversity is an essential step for conservation, and understanding the efficiency of sampling methods allows us to estimate the quality of our biodiversity data. Sex ratio is an important population characteristic, but until now, no study has evaluated how efficient are the sampling methods commonly used in biodiversity surveys in estimating the sex ratio of populations. We used a virtual ecologist approach to investigate whether active and passive capture methods are able to accurately sample a population's sex ratio and whether differences in movement pattern and detectability between males and females produce biased estimates of sex-ratios when using these methods. Our simulation allowed the recognition of individuals, similar to mark-recapture studies. We found that differences in both movement patterns and detectability between males and females produce biased estimates of sex ratios. However, increasing the sampling effort or the number of sampling days improves the ability of passive or active capture methods to properly sample sex ratio. Thus, prior knowledge regarding movement patterns and detectability for species is important information to guide field studies aiming to understand sex ratio related patterns.

Differences in Movement Pattern and Detectability between Males and Females Influence How Common Sampling Methods Estimate Sex Ratio

PubMed Central

Rodrigues, João Fabrício Mota; Coelho, Marco Túlio Pacheco

2016-01-01

Sampling the biodiversity is an essential step for conservation, and understanding the efficiency of sampling methods allows us to estimate the quality of our biodiversity data. Sex ratio is an important population characteristic, but until now, no study has evaluated how efficient are the sampling methods commonly used in biodiversity surveys in estimating the sex ratio of populations. We used a virtual ecologist approach to investigate whether active and passive capture methods are able to accurately sample a population’s sex ratio and whether differences in movement pattern and detectability between males and females produce biased estimates of sex-ratios when using these methods. Our simulation allowed the recognition of individuals, similar to mark-recapture studies. We found that differences in both movement patterns and detectability between males and females produce biased estimates of sex ratios. However, increasing the sampling effort or the number of sampling days improves the ability of passive or active capture methods to properly sample sex ratio. Thus, prior knowledge regarding movement patterns and detectability for species is important information to guide field studies aiming to understand sex ratio related patterns. PMID:27441554

The WHISK (Women's Health: Increasing the Awareness of Science and Knowledge) Pilot Project: Recognizing Sex and Gender Differences in Women's Health and Wellness.

PubMed

Edwards, Lorece V; Dennis, Sabriya; Weaks, Francesca

2013-09-01

Women's health encompasses a continuum of biological, psychological, and social challenges that differ considerably from those of men. Despite the remarkable advances in science, women's health and sex differences research is slowly gaining recognition and acceptance. It is important that women's health gain attention as women are usually the gatekeepers of care for the family. Women's health and health outcomes are strongly influenced by sex and gender differences as well as geography. Around the world, the interplay of biology and culture brings about differences in men's and women's health, which have been largely overlooked. The Women's Health: Increasing the Awareness of Science and Knowledge (WHISK) Pilot Project was a multidisciplinary project aimed to increase the awareness of sex and gender differences in women's health and research among healthcare professionals. Theater expression and creative art were used to translate knowledge, enhance understanding, and increase the awareness of sex differences. Findings from this project clearly showed an apparent increase in knowledge and cultivation of new insights.

Host Responses to the Pathogen Mycobacterium avium subsp. paratuberculosis and Beneficial Microbes Exhibit Host Sex Specificity

PubMed Central

McMahon, K. Wyatt; Chang, David; Brashears, Mindy M.

2014-01-01

Differences between microbial pathogenesis in male and female hosts are well characterized in disease conditions connected to sexual transmission. However, limited biological insight is available on variances attributed to sex specificity in host-microbe interactions, and it is most often a minimized variable outside these transmission events. In this work, we studied two gut microbes—a pathogen, Mycobacterium avium subsp. paratuberculosis, and a probiotic, Lactobacillus animalis NP-51—and the interaction between each agent and the male and female gastrointestinal systems. This trial was conducted in BALB/c mice (n = 5 per experimental group and per sex at a given time point), with analysis at four time points over 180 days. Host responses to M. avium subsp. paratuberculosis and L. animalis were sensitive to sex. Cytokines that were significantly different (P ≤ 0.05) between the sexes included interleukin-1α/β (IL-1α/β), IL-17, IL-6, IL-10, IL-12, and gamma interferon (IFN-γ) and were dependent on experimental conditions. However, granulocyte-macrophage colony-stimulating factor (GM-CSF), vascular endothelial growth factor (VEGF), and IL-13/23 showed no sex specificity. A metabolomics study indicated a 0.5- to 2.0-fold (log2 scale) increase in short-chain fatty acids (butyrate and acetate) in males and greater increases in o-phosphocholine or histidine from female colon tissues; variances distinct to each sex were observed with age or long-term probiotic consumption. Two genera, Staphylococcus and Roseburia, were consistently overrepresented in females compared to males; other species were specific to one sex but fluctuated depending on experimental conditions. The differences observed suggest that male and female gut tissues and microbiota respond to newly introduced microorganisms differently and that gut-associated microorganisms with host immune system responses and metabolic activity are supported by biology distinct to the host sex. PMID:24814797

Different sex ratios of children born to Indian and Pakistani immigrants in Norway

PubMed Central

2010-01-01

Background A low female-to-male ratio has been observed in different Asian countries, but this phenomenon has not been well studied among immigrants living in Western societies. In this study, we investigated whether a low female-to-male ratio exists among Indian and Pakistani immigrants living in Norway. In particular, we investigated whether the determination of sex via ultrasound examination, a common obstetric procedure that has been used in Norway since the early 1980 s, has influenced the female-to-male ratio among children born to parents of Indian or Pakistani origin. Methods We performed a retrospective cohort study of live births in mothers of Indian (n = 1597) and Pakistani (n = 5617) origin. Data were obtained from "Statistics Norway" and the female-to-male (F/M) sex ratio was evaluated among 21,325 children born, in increasing birth order, during three stratified periods (i.e., 1969-1986, 1987-1996, and 1997-2005). Results A significant low female-to-male sex ratio was observed among children in the third and fourth birth order (sex ratio 65; 95% CI 51-80) from mothers of Indian origin who gave birth after 1987. Sex ratios did not deviate from the expected natural variation in the Indian cohort from 1969 to 1986, and remained stable in the Pakistani cohort during the entire study period. However, the female-to-male sex ratio seemed less skewed in recent years (i.e., 1997-2005). Conclusion Significant differences were observed in the sex ratio of children born to mothers of Indian origin compared with children born to mothers of Pakistani origin. A skewed number of female births among higher birth orders (i.e., third or later) may partly reflect an increase in sex-selective abortion among mothers of Indian origin, although the numbers are too small to draw firm conclusions. Further research is needed to explain the observed differences in the female-to-male ratio among members of these ethnic groups who reside in Norway. PMID:20682027

An Action Research Project to Assess Middle School Educators' Professional Development Needs in Single-Sex Classrooms

ERIC Educational Resources Information Center

Simm, Lynnette Marie Gresham

2010-01-01

According to the National Association of Single-Sex Public Education (NASSPE, 2010), an increase of 540 public schools offering single-sex classrooms in the United States has occurred since 2001. Educators who understand the gender differences between boys and girls can inspire students to learn to the best of their ability; however, the problem…

Female Sex Offenders: Is There a Difference Between Solo and Co-Offenders?

PubMed

Ten Bensel, Tusty; Gibbs, Benjamin; Burkey, Chris Rush

2016-10-01

Studies on female sex offending have been limited for a number of reasons, such as societal perceptions that females are incapable of engaging in such behaviors because of their role as caretakers and nurturers in society. However, over the past few decades, studies examining female sex offenders have increased, revealing that females do commit sexual offenses and differ from their male counterparts. We examined offender, victim, and offense characteristics of female sex offenders who were convicted from 1995 to 2013 ( N = 223) in Arkansas and were sentenced to serve time in prison or placed on probation. We focused on the similarities and differences of solo and co-female sex offenders because we know from previous studies that the pathway of offending can differ between solo and co-female offenders, yet few studies have exclusively compared the similarities and differences among female sex offenders. Our data were collected from offender files that included basic personal offender information, offender survey and social history, criminal history, incident reports while incarcerated, court records, police investigation reports, initial offender and victim statements (prior to offender incarceration), and probation/parole reports. We believe the results of this study will provide further insight into the types of female sex offenders as well as the possible differences between co- and solo-offenders in relation to their victim preferences, risk levels, rehabilitation amenability, and recidivism propensities.

Sex-Specific Differences in the Association Between Childhood Adversity and Cardiovascular Disease in Adulthood: Evidence From a National Cohort Study.

PubMed

Garad, Yasmin; Maximova, Katerina; MacKinnon, Nathalie; McGrath, Jennifer J; Kozyrskyj, Anita L; Colman, Ian

2017-08-01

Childhood adversity increases the risk for cardiovascular disease (CVD) in adulthood. Previously proposed mechanisms suggest that the association is mediated by stress reactivity-known to be higher in women-and is aggravated by adult stress, but this has not yet been confirmed. Therefore, we investigated sex differences to better understand possible pathways from childhood adversity to CVD. The National Population Health Survey, a 15-year cohort study of Canadians aged 18-49 years at baseline was used. Logistic regression with interaction terms for sex and stressful life events was used to assess the risk of CVD after childhood adversity. In secondary analyses, we assessed mediation effects of depression, smoking, alcohol, exercise, and diet using the product of coefficient approach. Mediated moderation was subsequently used to explain sex-moderated effects. There was a strong association between childhood adversity and CVD (odds ratio [OR], 2.14; 95% confidence interval [CI], 1.56-2.94) for 3+ childhood adversities. The association was stronger with increasing stressful events, and female patients with 3+ stressful events exhibited the highest risk of CVD (OR, 4.40; 95% CI, 1.98-9.75). No association was found in men. Depression, smoking, and poor diet partially mediated the relationship between childhood adversity and CVD (14%, 9%, and 9%, respectively), but differences in these behaviours did not fully explain the sex-specific differences in the mediated moderation analysis. The effect of childhood adverse events on CVD is heightened among women, particularly women with stressful adulthoods, and this difference is not mediated by depression, smoking, or poor diet. These findings have important implications for understanding sex differences in CVD risk. Copyright © 2017 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.

Functional neuroimaging of sex differences in autobiographical memory recall.

PubMed

Young, Kymberly D; Bellgowan, Patrick S F; Bodurka, Jerzy; Drevets, Wayne C

2013-12-01

Autobiographical memory (AM) is episodic memory for personally experienced events. The brain areas underlying AM retrieval are known to include several prefrontal cortical and medial temporal lobe regions. Sex differences in AM recall have been reported in several behavioral studies, but the functional anatomical correlates underlying such differences remain unclear. This study used fMRI to compare the neural correlates of AM recall between healthy male and female participants (n = 20 per group). AM recall in response to positive, negative, and neutral cue words was compared to a semantic memory task involving the generation of examples from a category using emotionally valenced cues. Behaviorally, females recalled more negative and fewer positive AMs compared with males, while ratings of arousal, vividness, and memory age did not differ significantly between sexes. Males and females also did not differ significantly in their performance on control tasks. Neurophysiologically, females showed increased hemodynamic activity compared to males in the dorsolateral prefrontal cortex (DLPFC), dorsal anterior insula, and precuneus while recalling specific AMs (all valences combined); increased activity in the DLPFC, transverse temporal gyrus, and precuneus while recalling positive AMs; and increased activity in the anterior cingulate cortex, precuneus, amygdala, and temporopolar cortex when recalling negative AMs. When comparing positive to negative AMs directly, males and females differed in their BOLD responses in the hippocampus and DLPFC. We propose that the differential hemodynamic changes may reflect sex-specific cognitive strategies during recall of AMs irrespective of the phenomenological properties of those memories. Copyright © 2012 Wiley Periodicals, Inc.

Local differentiation and plasticity in size and sex expression in jack-in-the-pulpit, Arisaema triphyllum (Araceae).

PubMed

Vitt, Pati; Holsinger, Kent E; Jones, Cynthia S

2003-12-01

The size advantage hypothesis suggests that natural selection will favor size-dependent sex expression when one sex gains more than the other by being large. But members of a minority sex will also have a higher reproductive value, on average. Thus, an individual's reproductive success depends on the reproductive decisions made by neighboring individuals. As a result, the optimal relationship between size and sex may differ among populations. In Arisaema triphyllum, the probability for an individual to be female increases with size, regardless of the character measured. A reciprocal transplant experiment showed the relationship between size and sexual expression is environmentally plastic. Plants originating from our two study sites became female at a larger average size when grown at one site than when grown at the other. In addition to environmental influence on sex expression, the experiment demonstrated genetic differences in the relationship between size and sex. Plants collected from one site became female at a larger size than those from the other, regardless of where they were grown. Thus, while the environment in which an individual was grown had a substantial influence on its sex expression, populations only a few kilometers apart have genetically different relationships between size and sex.

Sex differences in cortisol's regulation of affiliative behavior.

PubMed

Sherman, Gary D; Rice, Leslie K; Jin, Ellie Shuo; Jones, Amanda C; Josephs, Robert A

2017-06-01

A contribution to a special issue on Hormones and Human Competition. A stress perspective is used to illuminate how competitive defeat and victory shape biology and behavior. We report a field study examining how change in cortisol following perceived defeat (vs. victory) in a competition-in this case, a dog agility competition-relates to affiliative behavior. Following competition, we measured cortisol change and the extent to which dog handlers directed affiliative behaviors toward their dogs. We found striking sex differences in affiliation. First, men were more affiliative toward their dogs after victory, whereas women were more affiliative after defeat. Second, the greater a female competitor's increase in cortisol, the more time she spent affiliating with her dog, whereas for men, the pattern was the exact opposite: the greater a male competitor's increase in cortisol, the less time he spent affiliating with his dog. This pattern suggests that, in the wake of competition, men and women's affiliative behavior may serve different functions-shared celebration for men; shared consolation for women. These sex differences show not only that men and women react very differently to victory and defeat, but also that equivalent changes in cortisol across the sexes are associated with strikingly different behavioral consequences for men and women. Copyright © 2016 Elsevier Inc. All rights reserved.

The influence of sex and gonadectomy on hepatic and brain fatty acid composition, lipogenesis and β-oxidation.

PubMed

Starčević, K; Filipović, N; Šperanda, M; Đidara, M; Mašek, T

2017-08-01

The aim of this study was to investigate the influence of sex and castration of rats on liver and brain fatty acid profile and liver mRNA expression of genes involved in lipogenesis and β-oxidation. Castration significantly increased body weight and liver index and decreased serum triglyceride content in the female rats. The fatty acid composition of the liver tissue was influenced by sex and castration. Male rats had higher content of C16:0, C18:1n7, C18:2n6 and C22:5n3, while female rats had higher content of C18:0, C20:4n6 and C22:6n3. Castration of male rats decreased differences caused by sex for C18:2n6, C20:4n6 and C22:6n3. Values for C16:1n7 were higher in the castrated male rats in comparison with all other groups. Liver phospholipids showed a distribution of fatty acids similar to the total lipids. Brain total lipids and phospholipids were not influenced by sex or castration. Castration increased ∆6D gene expression in both the sexes, while ∆5D and ∆9D increased in females and males respectively. Gonadectomy increased expression of the FASN gene in the females and decreased CPT1 and ACOX1 gene expression in the liver tissue of male rats. The observed results of lipid peroxidation, measured by TBARS, were the lowest in the intact females in comparison with all other groups. In conclusion, sex strongly influences both SFA and PUFA in liver tissue, and castration decreases these differences only for PUFA. Castration also influences the expression of the genes involved in lipid metabolism differently in male and female rats, with an increase in lipogenic genes in female rats and a decrease in key genes for mitochondrial and peroxisomal β-oxidation in male rats. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

Differential effects of military training on fat-free mass and plasma amino acid adaptations in men and women.

PubMed

Margolis, Lee M; Pasiakos, Stefan M; Karl, J Philip; Rood, Jennifer C; Cable, Sonya J; Williams, Kelly W; Young, Andrew J; McClung, James P

2012-12-18

Fat-free mass (FFM) adaptations to physical training may differ between sexes based on disparities in fitness level, dietary intake, and levels of plasma amino acids (AA). This investigation aimed to determine FFM and plasma AA responses to military training, examine whether adaptations differ between male and female recruits, and explore potential associations between FFM and AA responses to training. Body composition and plasma AA levels were assessed in US Army recruits (n = 209, 118 males, 91 females) before (baseline) and every three weeks during basic combat training (BCT), a 10-week military training course. Body weight decreased in men but remained stable in women during BCT (sex-by-time interaction, P < 0.05). Fifty-eight percent of recruits gained FFM during BCT, with more (P < 0.05) females (88%) gaining FFM than males (36%). Total plasma AA increased (P < 0.05) during BCT, with greater (P < 0.05) increases observed in females (17%) then in males (4%). Essential amino acids (EAA) and branched-chain amino acids (BCAA) were increased (P < 0.05) in females but did not change in males (sex-by-time interaction, P < 0.05). Independent of sex, changes in EAA (r = 0.34) and BCAA (r = 0.27) from baseline were associated with changes in FFM (P < 0.05); greater (P < 0.05) increases in AA concentrations were observed for those who gained FFM. Increases in FFM and plasma AA suggest that BCT elicits a more pronounced anabolic response in women compared to men, which may reflect sex-specific differences in the relative intensity of the combined training and physiological stimulus associated with BCT.

Differential Effects of Military Training on Fat-Free Mass and Plasma Amino Acid Adaptations in Men and Women

PubMed Central

Margolis, Lee M.; Pasiakos, Stefan M.; Karl, J. Philip; Rood, Jennifer C.; Cable, Sonya J.; Williams, Kelly W.; Young, Andrew J.; McClung, James P.

2012-01-01

Fat-free mass (FFM) adaptations to physical training may differ between sexes based on disparities in fitness level, dietary intake, and levels of plasma amino acids (AA). This investigation aimed to determine FFM and plasma AA responses to military training, examine whether adaptations differ between male and female recruits, and explore potential associations between FFM and AA responses to training. Body composition and plasma AA levels were assessed in US Army recruits (n = 209, 118 males, 91 females) before (baseline) and every three weeks during basic combat training (BCT), a 10-week military training course. Body weight decreased in men but remained stable in women during BCT (sex-by-time interaction, P < 0.05). Fifty-eight percent of recruits gained FFM during BCT, with more (P < 0.05) females (88%) gaining FFM than males (36%). Total plasma AA increased (P < 0.05) during BCT, with greater (P < 0.05) increases observed in females (17%) then in males (4%). Essential amino acids (EAA) and branched-chain amino acids (BCAA) were increased (P < 0.05) in females but did not change in males (sex-by-time interaction, P < 0.05). Independent of sex, changes in EAA (r = 0.34) and BCAA (r = 0.27) from baseline were associated with changes in FFM (P < 0.05); greater (P < 0.05) increases in AA concentrations were observed for those who gained FFM. Increases in FFM and plasma AA suggest that BCT elicits a more pronounced anabolic response in women compared to men, which may reflect sex-specific differences in the relative intensity of the combined training and physiological stimulus associated with BCT. PMID:23250145

Genetic conflict and sex chromosome evolution

PubMed Central

Meiklejohn, Colin D; Tao, Yun

2009-01-01

Chromosomal sex determination systems create the opportunity for the evolution of selfish genetic elements that increase the transmission of one sex chromosome at the expense of its homolog. Because such selfish elements on sex chromosomes can reduce fertility and distort the sex ratio of progeny, unlinked suppressors are expected to evolve, bringing different regions of the genome into conflict over the meiotic transmission of the sex chromosomes. Here we argue that recurrent genetic conflict over sex chromosome transmission is an important evolutionary force that has shaped a wide range of seemingly disparate phenomena including the epigenetic regulation of genes expressed in the germline, the distribution of genes in the genome, and the evolution of hybrid sterility between species. PMID:19931208

Sex differences in nitrosative stress during renal ischemia.

PubMed

Rodríguez, Francisca; Nieto-Cerón, Susana; Fenoy, Francisco J; López, Bernardo; Hernández, Isabel; Martinez, Raquel Rodado; Soriano, Ma José González; Salom, Miguel G

2010-11-01

Females suffer a less severe ischemic acute renal failure than males, apparently because of higher nitric oxide (NO) bioavailability and/or lower levels of oxidative stress. Because the renal ischemic injury is associated with outer medullary (OM) endothelial dysfunction, the present study evaluated sex differences in OM changes of NO and peroxynitrite levels (by differential pulse voltammetry and amperometry, respectively) during 45 min of ischemia and 60 min of reperfusion in anesthetized Sprague-Dawley rats. Endothelial nitric oxide synthase (eNOS) and neuronal nitric oxide synthase (nNOS) protein expression and their phosphorylated forms [peNOS(Ser1177) and pnNOS(Ser1417)], 3-nitrotyrosine, reduced sulfhydryl groups (-SH), and glomerular filtration rate (GFR) were also determined. No sex differences were observed in monomeric eNOS and nNOS expression, NO, or 3-nitrotyrosine levels in nonischemic kidneys, but renal -SH content was higher in females. Ischemia increased dimeric/monomeric eNOS and nNOS ratio more in females, but the dimeric phosphorylated peNOS(Ser1177) and pnNOS(Ser1417) forms rose similarly in both sexes, indicating no sex differences in nitric oxide synthase activation. However, NO levels increased more in females than in males (6,406.0 ± 742.5 and 4,058.2 ± 272.35 nmol/l respectively, P < 0.05), together with a lower increase in peroxynitrite current (5.5 ± 0.7 vs. 12.7 ± 1.5 nA, P < 0.05) and 3-nitrotyrosine concentration, (28.7 ± 3.7 vs. 48.7 ± 3.7 nmol/mg protein, P < 0.05) in females than in males and a better preserved GFR after ischemia in females than in males (689.7 ± 135.0 and 221.4 ± 52.5 μl·min(-1)·g kidney wt(-1), P < 0.01). Pretreatment with the antioxidants N-acetyl-L-cysteine or ebselen abolished sex differences in peroxynitrite, nitrotyrosine, and GFR, suggesting that a greater oxidative and nitrosative stress worsens renal damage in males.

Differential Risk Factors for HIV Drug and Sex Risk-Taking Among Non-treatment-seeking Hospitalized Injection Drug Users

PubMed Central

Crooks, Denise; Tsui, Judith; Anderson, Bradley; Dossabhoy, Shernaz; Herman, Debra; Liebschutz, Jane M.; Stein, Michael D.

2016-01-01

Injection drug users (IDUs) are at increased risk of contracting HIV. From a clinical trial assessing an intervention to enhance the linkage of hospitalized patients to opioid treatment after discharge, we conducted multivariate analysis of baseline data from hospitalized IDUs with a history of opioid dependence (n = 104) to identify differences in factors predicting HIV drug and sex risk behaviors. Factors significantly associated with HIV drug risk were being non-Hispanic Caucasian and recent cocaine use. Being female, binge drinking, and poorer mental health were significantly associated with higher sex risk. Because factors predicting HIV sex risk behaviors differ from those predicting HIV drug risk, interventions aimed at specific HIV risks should have different behavioral and substance use targets. PMID:25063229

Liver phospholipids fatty acids composition in response to different types of diets in rats of both sexes.

PubMed

Ranković, Slavica; Popović, Tamara; Martačić, Jasmina Debeljak; Petrović, Snježana; Tomić, Mirko; Ignjatović, Đurđica; Tovilović-Kovačević, Gordana; Glibetić, Maria

2017-05-19

Dietary intake influence changes in fatty acids (FA) profiles in liver which plays a central role in fatty acid metabolism, triacylglycerol synthesis and energy homeostasis. We investigated the effects of 4-weeks treatment with milk- and fish-based diet, on plasma biochemical parameters and FA composition of liver phospholipids (PL) in rats of both sexes. Adult, 4 months old, Wistar rats of both sexes, were fed with different types of diets: standard, milk-based and fish-based, during 4 weeks. Analytical characterization of different foods was done. Biochemical parameters in plasma were determined. Fatty acid composition was analyzed by gas-chromatography. Statistical significance of FA levels was tested with two-way analysis of variance (ANOVA) using the sex of animals and treatment (type of diet) as factors on logarithmic or trigonometric transformed data. Our results showed that both, milk- and fish-based diet, changed the composition and ratio of rat liver phospholipids FA, in gender-specific manner. Initially present sex differences appear to be dietary modulated. Although, applied diets changed the ratio of total saturated fatty acids (SFA), monounsaturated fatty acids (MUFA) and polyunsaturated fatty acids (PUFA), and effects were gender specific. Milk-based diet lowered SFA and elevated MUFA in males and increased PUFA in females vs. standard diet. The same diet decreased n-3, increased n-6 and n-6/n-3 ratio in males. Fish-based diet increased n-3, decreased n-6 and n-6/n-3 ratio vs. standard and milk-based diet in females. However, the ratio of individual FA in liver PL was also dietary-influenced, but with gender specific manner. While in females fish-based diet decreased AA (arachidonic acid) increased level of EPA (eicosapentaenoic acid), DPA (docosapentaenoic acid) and DHA (docosahexaenoic acid), the same diet elevated only DHA levels in males. Gender related variations in FA composition of rat liver PL were observed, and results have shown that those initial differences could be significantly modulated by the type of diet. Furthermore, the modulatory effects of milk- and fish-based diets on liver phospholipids FA profiles appeared to be sex-specific.

Sex and Exercise Interact to Alter the Expression of Anabolic Androgenic Steroid-Induced Anxiety-Like Behaviors in the Mouse

PubMed Central

Onakomaiya, Marie M.; Porter, Donna M.; Oberlander, Joseph G.; Henderson, Leslie P.

2014-01-01

Anabolic androgenic steroids (AAS) are taken by both sexes to enhance athletic performance and body image, nearly always in conjunction with an exercise regime. Although taken to improve physical attributes, chronic AAS use can promote negative behavior, including anxiety. Few studies have directly compared the impact of AAS use in males versus females or assessed the interaction of exercise and AAS. We show that AAS increase anxiety-like behaviors in female but not male mice and that voluntary exercise accentuates these sex-specific differences. We also show that levels of the anxiogenic peptide corticotrophin releasing factor (CRF) are significantly greater in males, but that AAS selectively increase CRF levels in females, thus abrogating this sex-specific difference. Exercise did not ameliorate AAS-induced anxiety or alter CRF levels in females. Exercise was anxiolytic in males, but this behavioral outcome did not correlate with CRF levels. Brain-derived neurotrophic factor (BDNF) has also been implicated in the expression of anxiety. As with CRF, levels of hippocampal BDNF mRNA were significantly greater in males than females. AAS and exercise were without effect on BDNF mRNA in females. In males, anxiolytic effects of exercise correlated with increased BDNF mRNA, however AAS-induced changes in BDNF mRNA and anxiety did not. In sum, we find that AAS elicit sex-specific differences in anxiety and that voluntary exercise accentuates these differences. In addition, our data suggest that these behavioral outcomes may reflect convergent actions of AAS and exercise on a sexually differentiated CRF signaling system within the extended amygdala. PMID:24768711

Sex differences in mortality in Denmark during half a century, 1943-92.

PubMed

Helweg-Larsen, K; Juel, K

2000-09-01

The emphasis of this study is on the relative mortality of 45-74-year-old men and women in Denmark in 1943-92, following economic and political changes that have affected the social meaning of gender over the last 50 years, and which have diminished former sex differences in health behaviour. Sex ratios of total mortality and mortality from major non-sex-specific causes of death were calculated on computerized mortality data from the Danish National Cause of Death Register that covers all deaths in Denmark since 1943. In the early 1940s the sex ratio of all-cause mortality was low, 1.0-1.1, it increased to a peak level in the late 1970s and early 1980s, but has since decreased due to an increase in female mortality and a more favourable trend in male mortality. Gender equality, employment, and economic autonomy may have beneficial health effects on both men and women, but the effects are inconsistent. The trend in smoking is the major explanatory factor for the more recent trends in gender differentials in mortality in Denmark.

Motor vehicle and fall related deaths among older Americans 1990-98: sex, race, and ethnic disparities.

PubMed

Stevens, J A; Dellinger, A M

2002-12-01

To examine differences in motor vehicle and fall related death rates among older adults by sex, race, and ethnicity. Annual mortality tapes for 1990-98 provided demographic data including race and ethnicity, date, and cause of death. Trend analyses were conducted using Poisson regression. From 1990-98, overall motor vehicle related death rates remained stable while death rates from unintentional falls increased. Motor vehicle and fall related death rates were higher among men. Motor vehicle related death rates were higher among people of color while fall related death rates were higher among whites. Among whites, fall death rates increased significantly during the study period, with an annual relative increase of 3.6% for men and 3.2% for women. The risk of death from motor vehicle and fall related injuries among older adults differed by sex, race and ethnicity, results obscured by simple age and sex specific death rates. This study found important patterns and disparities in these death rates by race and ethnicity useful for identifying high risk groups and guiding prevention strategies.

Attend or defend? Sex differences in behavioral, autonomic, and respiratory response patterns to emotion-eliciting films.

PubMed

Wilhelm, Frank H; Rattel, Julina A; Wegerer, Melanie; Liedlgruber, Michael; Schweighofer, Simon; Kreibig, Sylvia D; Kolodyazhniy, Vitaliy; Blechert, Jens

2017-12-01

Sex differences in emotional reactivity have been studied primarily for negative but less so for positive stimuli; likewise, sex differences in the psychophysiological response-patterning during such stimuli are poorly understood. Thus, the present study examined sex differences in response to negative/positive and high/low arousing films (classified as threat-, loss-, achievement-, and recreation-related, vs. neutral films), while measuring 18 muscular, autonomic, and respiratory parameters. Sex differences emerged for all films, but were most prominent for threat-related films: Despite equivalent valence and arousal ratings, women displayed more facial-muscular and respiratory responding than men and pronounced sympathetic activation (preejection period, other cardiovascular and electrodermal measures), while men showed coactivated sympathetic/parasympathetic responding (including increased respiratory sinus arrhythmia). This indicates a prototypical threat-related defense response in women, while men showed a pattern of sustained orienting, which can be understood as a shift toward less threat proximity in the defense cascade model. Clinical implications are discussed within a socio-evolutionary framework. Copyright © 2017 Elsevier B.V. All rights reserved.

Partner violence, power, and gender differences in South African adolescents' HIV/sexually transmitted infections risk behaviors.

PubMed

Teitelman, Anne M; Jemmott, John B; Bellamy, Scarlett L; Icard, Larry D; O'Leary, Ann; Heeren, G Anita; Ngwane, Zolani; Ratcliffe, Sarah J

2016-07-01

Low relationship power and victimization by intimate partner violence (IPV) have been linked to HIV risks among adult and adolescent women. This article examines associations of IPV and relationship power with sexual-risk behaviors and whether the associations differ by gender among South African adolescents. Sexual-risk behaviors (multiple partners in past 3 months; condom use at last sex), IPV, and relationship power were collected from 786 sexually experienced adolescents (mean age = 16.9) in Eastern Cape Province, South Africa, during the 54-month follow-up of a HIV/sexually transmitted infection (STI) risk-reduction intervention trial. The data were analyzed with logistic regression models. Adolescent boys were less likely to report condom use at last sex (p = .001) and more likely to report multiple partners (p < .001). A Gender × IPV interaction (p = .002) revealed that as IPV victimization increased, self-reported condom use at last sex decreased among girls, but increased among boys. A Gender × Relationship Power interaction (p = .004) indicated that as relationship power increased, self-reported condom use at last sex increased among girls, but decreased among boys. A Gender × IPV interaction (p = .004) indicated that as IPV victimization increased, self-reports of having multiple partners increased among boys, but not among girls. As relationship power increased, self-reports of having multiple partners decreased irrespective of gender. HIV risk-reduction interventions and policies should address gender differences in sexual-risk consequences of IPV and relationship power among adolescents and promote gender equity. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

How to study sex differences in addiction using animal models

PubMed Central

Carroll, Marilyn E.; Lynch, Wendy J.

2016-01-01

The importance of studying sex as a biological variable in biomedical research is becoming increasingly apparent. There is a particular need in preclinical studies of addiction to include both sexes, as female animals are often excluded from studies, leaving large gaps in our knowledge of not only sex differences and potential prevention and treatment strategies, but also with regard to the basic neurobiology of addiction. This review focuses on methodology that has been developed in preclinical studies to examine sex differences in the behavioral aspects and neurobiological mechanisms related to addiction across the full range of the addiction process, including initiation (acquisition), maintenance, escalation, withdrawal, relapse to drug seeking and treatment. This review also discusses strategic and technical issues that need to be considered when comparing females and males, including the role of ovarian hormones and how sex differences interact with other major vulnerability factors in addiction, such as impulsivity, compulsivity and age (adolescent vs. adult). Novel treatments for addiction are also discussed, such as competing nondrug rewards, repurposed medications such as progesterone and treatment combinations. Practical aspects of conducting research comparing female and male animals are also considered. Making sex differences a point of examination requires additional effort and consideration; however, such studies are necessary given mounting evidence demonstrating that the addiction process occurs differently in males and females. These studies should lead to a better understanding of individual differences in the development of addiction and effective treatments for males and females. PMID:27345022

Structural and biomechanical basis of sexual dimorphism in femoral neck fragility has its origins in growth and aging.

PubMed

Duan, Yunbo; Beck, Thomas J; Wang, Xiao-Fang; Seeman, Ego

2003-10-01

The structural basis for sex differences in femoral neck (FN) fragility was studied in 1196 subjects and 307 patients with hip fracture. The absolute and relative patterns of modeling and remodeling on the periosteal and endocortical envelopes during growth and aging produce changes in FN geometry and structure that results in FN fragility in both sexes and sexual dimorphism in hip fracture risk in old age. Femoral neck (FN) fragility in old age is usually attributed to age-related bone loss, while the sex differences in hip fracture rate are attributed to less bone loss in men than in women. The purpose of this study was to define the structural and biomechanical basis underlying the increase in FN fragility in elderly men and women and the structural basis of sex differences in hip fracture incidence in old age. We measured FN dimensions and areal bone mineral density in 1196 healthy subjects (801 females) 18-92 years of age and 307 patients (180 females) with hip fracture using DXA. We then used the DXA-derived FN areal bone mineral density (BMD) and measured periosteal diameter to estimate endocortical diameter, cortical thickness, section modulus (a measure of bending strength), and buckling ratio (indices for structural stability). Neither FN cortical thickness nor volumetric density differed in young adult women and men after height and weight adjustment. The sex differences in geometry were confined to the further displacement of the cortex from the FN neutral axis in young men, which produced 13.4% greater bending strength than in young women. Aging amplified this geometric difference; widening of the periosteal and endocortical diameters continued in both sexes but was greater in men, shifting the cortex even further from the neutral axis maintaining bending strength in men, not in women. In both sexes, less age-related periosteal than endocortical widening produced cortical thinning increasing the risk for structural failure by local buckling of the enlarged thin walled FN. Relative to age-matched controls, women and men with hip fractures had reduced cortical thickness, but FN periosteal diameter was increased in women and reduced in men, differences are likely to be originated in growth. The absolute and relative patterns of modeling and remodeling on the periosteal and endocortical envelopes during growth and aging produce changes in FN diameters, cortical thickness, and geometry that results in FN fragility in both sexes and sexual dimorphism in hip fracture risk in old age.

Preadolescent Clues to Understanding Depression in Girls

ERIC Educational Resources Information Center

Keenan, Kate; Hipwell, Alison E.

2005-01-01

Between the ages of 10 and 15, increases in depression among girls result in a rate that is twice as high as the rate of depression in boys. This sex difference remains throughout early and middle adulthood. Prior to early adolescence, there is essentially no sex difference in the rate of depression. The aim of the present review is to examine…

Are Apparent Sex Differences in Mean IQ Scores Created in Part by Sample Restriction and Increased Male Variance?

ERIC Educational Resources Information Center

Dykiert, Dominika; Gale, Catharine R.; Deary, Ian J.

2009-01-01

This study investigated the possibility that apparent sex differences in IQ are at least partly created by the degree of sample restriction from the baseline population. We used a nationally representative sample, the 1970 British Cohort Study. Sample sizes varied from 6518 to 11,389 between data-collection sweeps. Principal components analysis of…

Sex differences in psychological adjustment from infancy to 8 years.

PubMed

Prior, M; Smart, D; Sanson, A; Oberklaid, F

1993-03-01

The objective of this study was to explore sex differences in development from infancy to 8 years of age in a community sample. Measures of biological, social, interactive, and parental functioning as well as teacher reports were obtained. There were minimal differences in infancy, but major psychosocial differences emerged with increasing age. In the biological sphere boys were disadvantaged only in ratings of language and motor skills at 3 to 4 years old. They showed greater temperamental "difficulty" and low persistence factor scores from 5 years onward. Boys were significantly more likely to have problems with adaptive behavior and social competence and to show behavior problems of the hyperactive and aggressive type, as rated by mothers. Parent and family functioning measures did not differentiate between the sexes. Teachers rated boys as having more problems in academic and behavioral domains the first 3 years of school. Path analyses combining data sets gathered when the children were 3 to 8 years old demonstrated the differential courses of development for boys and girls although temperamental flexibility was the best predictor of behavioral adjustment for both sexes. A social learning explanation of the increased incidence of problems among males is supported, although biological influences are not ruled out.

Does Maltreatment in Childhood Affect Sexual Orientation in Adulthood?

PubMed Central

Roberts, Andrea L.; Glymour, M. Maria; Koenen, Karestan C.

2012-01-01

Epidemiological studies find a positive association between physical and sexual abuse, neglect, and witnessing violence in childhood and same-sex sexuality in adulthood, but studies directly assessing the association between these diverse types of maltreatment and sexuality cannot disentangle the causal direction because the sequencing of maltreatment and emerging sexuality is difficult to ascertain. Nascent same-sex orientation may increase risk of maltreatment; alternatively, maltreatment may shape sexual orientation. Our study used instrumental variable models based on family characteristics that predict maltreatment but are not plausibly influenced by sexual orientation (e.g., having a stepparent) as natural experiments to investigate whether maltreatment might increase the likelihood of same-sex sexuality in a nationally representative sample (n = 34,653). In instrumental variable models, history of sexual abuse predicted increased prevalence of same-sex attraction by 2.0 percentage points (95% confidence interval [CI] = 1.4, 2.5), any same-sex partners by 1.4 percentage points (95% CI = 1.0, 1.9), and same-sex identity by 0.7 percentage points (95% CI = 0.4, 0.9). Effects of sexual abuse on men’s sexual orientation were substantially larger than on women’s. Effects of non-sexual maltreatment were significant only for men and women’s sexual identity and women’s same-sex partners. While point estimates suggest much of the association between maltreatment and sexual orientation may be due to the effects of maltreatment on sexual orientation, confidence intervals were wide. Our results suggest that causal relationships driving the association between sexual orientation and childhood abuse may be bidirectional, may differ by type of abuse, and may differ by sex. Better understanding of this potentially complex causal structure is critical to developing targeted strategies to reduce sexual orientation disparities in exposure to abuse. PMID:22976519

Characterization of juvenile play in rats: importance of sex of self and sex of partner.

PubMed

Argue, Kathryn J; McCarthy, Margaret M

2015-01-01

Juvenile social play is observed in many mammalian species, and its disruption in several neuropsychiatric disorders has greatly increased interest in understanding the origins and sources of variability in this behavior. We quantified social play behavior in juvenile rats and investigated the impact of sex and familiarity of the play partner. Sex differences in play behavior were investigated by comparing males and females from either same- or mixed-sex pairs with data pooled over 12 days of analysis. Whether play was altered based on the sex of the play partner was assessed using a paired analysis to compare play with a same- or opposite-sex play partner for both males and females. Additionally, a repeated measures design was utilized to determine whether play changed with increasing age. On postnatal day 33, a novel play partner was introduced. We used a repeated measures analysis to compare postnatal day 33 with the previous day. These approaches were used to assess the effects of age, sex, sex of partner, and familiarity of partner on total social play behavior as well as how play was broken down into components, such as pouncing, pinning, chasing, and boxing. There were sex differences in total frequency of play, and specific parameters of play behavior, such as chasing, pouncing, pinning, and boxing. Additionally, males significantly altered their play behavior in response to the sex of their play partner, whereas females were more sensitive to the familiarity of the play partner. This study provides critical groundwork for uncovering factors that regulate social play behavior and can be used to guide future mechanistic based work.

Sex differences in the use of social information emerge under conditions of risk.

PubMed

Brand, Charlotte O; Brown, Gillian R; Cross, Catharine P

2018-01-01

Social learning provides an effective route to gaining up-to-date information, particularly when information is costly to obtain asocially. Theoretical work predicts that the willingness to switch between using asocial and social sources of information will vary between individuals according to their risk tolerance. We tested the prediction that, where there are sex differences in risk tolerance, altering the variance of the payoffs of using asocial and social information differentially influences the probability of social information use by sex. In a computer-based task that involved building a virtual spaceship, men and women ( N  = 88) were given the option of using either asocial or social sources of information to improve their performance. When the asocial option was risky (i.e., the participant's score could markedly increase or decrease) and the social option was safe (i.e., their score could slightly increase or remain the same), women, but not men, were more likely to use the social option than the asocial option. In all other conditions, both women and men preferentially used the asocial option to a similar degree. We therefore found both a sex difference in risk aversion and a sex difference in the preference for social information when relying on asocial information was risky, consistent with the hypothesis that levels of risk-aversion influence the use of social information.

Sex differences in the use of social information emerge under conditions of risk

PubMed Central

Brand, Charlotte O.; Brown, Gillian R.

2018-01-01

Social learning provides an effective route to gaining up-to-date information, particularly when information is costly to obtain asocially. Theoretical work predicts that the willingness to switch between using asocial and social sources of information will vary between individuals according to their risk tolerance. We tested the prediction that, where there are sex differences in risk tolerance, altering the variance of the payoffs of using asocial and social information differentially influences the probability of social information use by sex. In a computer-based task that involved building a virtual spaceship, men and women (N = 88) were given the option of using either asocial or social sources of information to improve their performance. When the asocial option was risky (i.e., the participant’s score could markedly increase or decrease) and the social option was safe (i.e., their score could slightly increase or remain the same), women, but not men, were more likely to use the social option than the asocial option. In all other conditions, both women and men preferentially used the asocial option to a similar degree. We therefore found both a sex difference in risk aversion and a sex difference in the preference for social information when relying on asocial information was risky, consistent with the hypothesis that levels of risk-aversion influence the use of social information. PMID:29312821

Sex- and dose-dependency in the pharmacokinetics and pharmacodynamics of (+)-methamphetamine and its metabolite (+)-amphetamine in rats

DOE Office of Scientific and Technical Information (OSTI.GOV)

Milesi-Halle, Alessandra; Hendrickson, Howard P.; Laurenzana, Elizabeth M.

These studies investigated how (+)-methamphetamine (METH) dose and rat sex affect the pharmacological response to METH in Sprague-Dawley rats. The first set of experiments determined the pharmacokinetics of METH and its pharmacologically active metabolite (+)-amphetamine (AMP) in male and female Sprague-Dawley rats after 1.0 and 3.0 mg/kg METH doses. The results showed significant sex-dependent changes in METH pharmacokinetics, and females formed significantly lower amounts of AMP. While the area under the serum concentration-time curve in males increased proportionately with the METH dose, the females showed a disproportional increase. The sex differences in systemic clearance, renal clearance, volume of distribution, andmore » percentage of unchanged METH eliminated in the urine suggested dose-dependent pharmacokinetics in female rats. The second set of studies sought to determine the behavioral implications of these pharmacokinetic differences by quantifying locomotor activity in male and female rats after saline, 1.0, and 3.0 mg/kg METH. The results showed sex- and dose-dependent differences in METH-induced locomotion, including profound differences in the temporal profile of effects at higher dose. These findings show that the pharmacokinetic and metabolic profile of METH (slower METH clearance and lower AMP metabolite formation) plays a significant role in the differential pharmacological response to METH in male and female rats.« less

Condoms for prisoners: no evidence that they increase sex in prison, but they increase safe sex

PubMed Central

Butler, Tony; Richters, Juliet; Yap, Lorraine; Donovan, Basil

2013-01-01

Objectives To determine if the provision of condoms to prisoners in two Australian state prison systems with different policies affects sexual behaviour. In New South Wales’ (NSW) prisons, condoms are freely distributed, while in Queensland prisons none are distributed. Methods We used a computer-assisted telephone interview to survey randomly selected prisoners in both states about their sexual behaviour in prison. Results Two thousand and eighteen male prisoners participated. The proportion of prisoners reporting anal sex in prison was equally low in NSW (3.3%) and Queensland (3.6%; p=0.8). A much higher proportion of prisoners who engaged in anal sex in NSW (56.8%) than Queensland (3.1%; p<0.0001) reported they had used a condom if they had had anal sex in prison. Sexual coercion was equally rare in both prison systems. Conclusions We found no evidence that condom provision to prisoners increased consensual or non-consensual sexual activity in prison. If available, condoms were much more likely to be used during anal sex. Condoms should be made available to prisoners as a basic human right. PMID:23300337

Sex Work Venue and Condom Use among Female Sex Workers in Senggigi, Indonesia

PubMed Central

Safika, Iko; Levy, Judith A.; Johnson, Timothy P.

2013-01-01

This paper examines the structural influence of sex work venues on condom use among female sex workers in the Senggigi area of Lombok, Indonesia. A cross-sectional design employing ethnographic observation, structured interviews and hierarchical linear modeling was used to examine condom use among female sex workers who solicited clients at three types of sex work venues: freelance, brothels, and entertainment places (karaoke bars and massage parlours). The sample consisted of 115 women “nested” within 16 sex work venues drawn from the three venue types. Rate (39%) of condom use varied across sex work venues. Perceived management style, HIV/AIDS-related policies, and risk-reduction services differed by venue, but this variation did not explain differences in condom use. At the individual level, higher condom use was associated with female sex workers having ever been married. At the client level, condoms were more likely to be used with foreign rather than domestic/local Indonesian clients. Low rates of condom use among Indonesian female sex workers during commercial sex suggests the need for increased HIV prevention efforts that acknowledge sex worker characteristics and relationships with clients that place them at risk. Future research into the effects of social context on HIV risk should also be considered. PMID:23472595

Sex work venue and condom use among female sex workers in Senggigi, Indonesia.

PubMed

Safika, Iko; Levy, Judith A; Johnson, Timothy P

2013-01-01

This paper examines the structural influence of sex work venues on condom use among female sex workers in the Senggigi area of Lombok, Indonesia. A cross-sectional design employing ethnographic observation, structured interviews and hierarchical linear modelling was used to examine condom use among female sex workers who solicited clients at three types of sex work venues: (1) freelance locations, (2) brothels and (3) entertainment places (karaoke bars and massage parlours). The sample consisted of 115 women 'nested' within 16 sex work venues drawn from the three venue types. Rate (39%) of condom use varied across sex work venues. Perceived management style, HIV/AIDS-related policies and risk-reduction services differed by venue, but this variation did not explain differences in condom use. At the individual level, higher condom use was associated with female sex workers having ever been married. At the client level, condoms were more likely to be used with foreign rather than domestic/local Indonesian clients. Low rates of condom use among Indonesian female sex workers during commercial sex suggests the need for increased HIV-prevention efforts that acknowledge sex worker characteristics and relationships with clients that place them at risk. Future research into the effects of social context on HIV risk should also be considered.

Subjective Responses to Caffeine Are Influenced by Caffeine Dose, Sex, and Pubertal Stage

PubMed Central

Ziegler, Amanda M.; Martin, Catherine; de Wit, Harriet

2015-01-01

Background: Our previous work has shown that there are sex differences in subjective responses to acute caffeine administration in adolescents. The purpose of this study was to determine if these sex differences are dependent on pubertal development. Materials and Methods: We examined subjective responses before and after administration of 0, 1, and 2 mg/kg of caffeine in pre- and postpubertal boys and girls (n = 112). In addition, we examined differences in subjective responses to acute caffeine in both the luteal and follicular phases of the menstrual cycle in postpubertal girls. Results: Caffeine at both doses resulted in greater changes in responses on the Addiction Research Center Inventory and the Brief Assessment of Mood States compared with placebo. Girls reported greater increases from baseline to peak in feeling different and liking the feeling than boys after 2 mg/kg of caffeine regardless of pubertal stage. Postpubertal girls also had a greater decrease from baseline in reports of feeling high and greater increases from baseline in reports of wanting more than postpubertal males. Finally, girls had greater changes (both increases and decreases) in responses on the Brief Mood Questionnaire when in the follicular phase compared with the luteal phase. This was also true for reports of feeling high and feeling different on the Drug Effects Questionnaire. None of these effects varied as a function of usual caffeine use, suggesting that differences are not the result of tolerance or sensitization. Conclusions: These results suggest that subjective responses to caffeine emerge before puberty, but sex differences may be strengthened after pubertal development. PMID:26649252

Individual differences in brain structure underpin empathizing-systemizing cognitive styles in male adults.

PubMed

Lai, Meng-Chuan; Lombardo, Michael V; Chakrabarti, Bhismadev; Ecker, Christine; Sadek, Susan A; Wheelwright, Sally J; Murphy, Declan G M; Suckling, John; Bullmore, Edward T; Baron-Cohen, Simon

2012-07-16

Individual differences in cognitive style can be characterized along two dimensions: 'systemizing' (S, the drive to analyze or build 'rule-based' systems) and 'empathizing' (E, the drive to identify another's mental state and respond to this with an appropriate emotion). Discrepancies between these two dimensions in one direction (S>E) or the other (E>S) are associated with sex differences in cognition: on average more males show an S>E cognitive style, while on average more females show an E>S profile. The neurobiological basis of these different profiles remains unknown. Since individuals may be typical or atypical for their sex, it is important to move away from the study of sex differences and towards the study of differences in cognitive style. Using structural magnetic resonance imaging we examined how neuroanatomy varies as a function of the discrepancy between E and S in 88 adult males from the general population. Selecting just males allows us to study discrepant E-S profiles in a pure way, unconfounded by other factors related to sex and gender. An increasing S>E profile was associated with increased gray matter volume in cingulate and dorsal medial prefrontal areas which have been implicated in processes related to cognitive control, monitoring, error detection, and probabilistic inference. An increasing E>S profile was associated with larger hypothalamic and ventral basal ganglia regions which have been implicated in neuroendocrine control, motivation and reward. These results suggest an underlying neuroanatomical basis linked to the discrepancy between these two important dimensions of individual differences in cognitive style. Copyright © 2012 Elsevier Inc. All rights reserved.

Sex differences in stroke therapies.

PubMed

Sohrabji, Farida; Park, Min Jung; Mahnke, Amanda H

2017-01-02

Stroke is the fifth leading cause of death and acquired disability in aged populations. Women are disproportionally affected by stroke, having a higher incidence and worse outcomes than men. Numerous preclinical studies have discovered novel therapies for the treatment of stroke, but almost all of these have been shown to be unsuccessful in clinical trials. Despite known sex differences in occurrence and severity of stroke, few preclinical or clinical therapeutics take into account possible sex differences in treatment. Reanalysis of data from studies of tissue plasminogen activator (tPA), the only currently FDA-approved stroke therapy, has shown that tPA improves stroke outcomes for both sexes and also shows sexual dimorphism by more robust improvement in stroke outcome in females. Experimental evidence supports the inclusion of sex as a variable in the study of a number of novel stroke drugs and therapies, including preclinical studies of anti-inflammatory drugs (minocycline), stimulators of cell survival (insulin-like growth factor-1), and inhibitors of cell death pathways (pharmacological inhibition of poly[ADP-ribose] polymerase-1, nitric oxide production, and caspase activation) as well as in current clinical trials of stem cell therapy and cortical stimulation. Overall, study design and analysis in clinical trials as well as in preclinical studies must include both sexes equally, consider possible sex differences in the analyses, and report the differences/similarities in more systematic/structured ways to allow promising therapies for both sexes and increase stroke recovery. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Proximal risk factors and suicide methods among suicide completers from national suicide mortality data 2004-2006 in Korea.

PubMed

Im, Jeong-Soo; Choi, Soon Ho; Hong, Duho; Seo, Hwa Jeong; Park, Subin; Hong, Jin Pyo

2011-01-01

This study was conducted to examine differences in proximal risk factors and suicide methods by sex and age in the national suicide mortality data in Korea. Data were collected from the National Police Agency and the National Statistical Office of Korea on suicide completers from 2004 to 2006. The 31,711 suicide case records were used to analyze suicide rates, methods, and proximal risk factors by sex and age. Suicide rate increased with age, especially in men. The most common proximal risk factor for suicide was medical illness in both sexes. The most common proximal risk factor for subjects younger than 30 years was found to be a conflict in relationships with family members, partner, or friends. Medical illness was found to increase in prevalence as a risk factor with age. Hanging/Suffocation was the most common suicide method used by both sexes. The use of drug/pesticide poisoning to suicide increased with age. A fall from height or hanging/suffocation was more popular in the younger age groups. Because proximal risk factors and suicide methods varied with sex and age, different suicide prevention measures are required after consideration of both of these parameters. Copyright © 2011 Elsevier Inc. All rights reserved.

Sex-Specific Impact of Ischemic Preconditioning on Tissue Oxygenation and Maximal Concentric Force

PubMed Central

Paradis-Deschênes, Pénélope; Joanisse, Denis R.; Billaut, François

2017-01-01

Prior peripheral hypoxia induced via remote ischemic preconditioning (IPC) can improve physical performance in male athletes through improved O2 delivery and utilization. Since females may have an innate protective mechanism against ischemia-reperfusion injury, and since muscle metabolism during contraction differs between sexes, it is relevant to examine the impact of sex in response to IPC to determine whether it is also ergogenic in females. In a randomized, crossover, single-blind study, we investigated muscle performance, hemodynamic and O2 uptake in strength-trained males (n = 9) and females (n = 8) performing five sets of 5 maximum voluntary knee extensions on an isokinetic dynamometer, preceded by either IPC (3 × 5-min ischemia/5-min reperfusion cycles at 200 mmHg) or SHAM (20 mmHg). Changes in deoxy-hemoglobin (Δ[HHb], expressed in percentage of arterial occlusion and considered an index of O2 extraction), and total hemoglobin (Δ[THb]) concentrations of the vastus lateralis muscle were continuously monitored by near-infrared spectroscopy. The metabolic efficiency of the contractions was calculated as the average force/Δ[HHb]avg ratio. Cohen's effect sizes (ES) ± 90% confidence limits were used to estimate IPC-induced changes and sex differences. IPC increased total muscular force in males only (13.0%, ES 0.64, 0.37;0.90), and this change was greater than in females (10.4% difference, ES 0.40, 0.10;0.70). Percent force decrement was only attenuated in females (−19.8%, ES −0.38, −0.77;0.01), which was clearly different than males (sex difference: ES 0.45, −0.16;1.07). IPC also induced different changes between sexes for average muscle O2 uptake in set 2 (males: 6.4% vs. females: −16.7%, ES 0.21, −0.18;0.60), set 3 (males: 7.0% vs. females: −44.4%, ES 0.56, −0.17;1.29), set 4 (males: 9.1% vs. females: −40.2%, ES 0.51, −0.10;1.13), and set 5 (males: 10.2% vs. females: −40.4%, ES 0.52, −0.04;1.09). However, metabolic efficiency was not meaningfully different between conditions and sexes. IPC increased muscle blood volume (↑[THb]) at rest and during recovery between sets, to the same extent in both sexes. Despite a similar IPC-induced initial increase in O2 delivery in both sexes, males displayed greater peripheral O2 extraction and greater strength enhancement. This ergogenic effect appears to be mediated in part via an up regulated oxidative function in males. We conclude that strength-trained males might benefit more from IPC than their female counterparts during repeated, maximal efforts. PMID:28105020

Sex-Specific Impact of Ischemic Preconditioning on Tissue Oxygenation and Maximal Concentric Force.

PubMed

Paradis-Deschênes, Pénélope; Joanisse, Denis R; Billaut, François

2016-01-01

Prior peripheral hypoxia induced via remote ischemic preconditioning (IPC) can improve physical performance in male athletes through improved O 2 delivery and utilization. Since females may have an innate protective mechanism against ischemia-reperfusion injury, and since muscle metabolism during contraction differs between sexes, it is relevant to examine the impact of sex in response to IPC to determine whether it is also ergogenic in females. In a randomized, crossover, single-blind study, we investigated muscle performance, hemodynamic and O 2 uptake in strength-trained males ( n = 9) and females ( n = 8) performing five sets of 5 maximum voluntary knee extensions on an isokinetic dynamometer, preceded by either IPC (3 × 5-min ischemia/5-min reperfusion cycles at 200 mmHg) or SHAM (20 mmHg). Changes in deoxy-hemoglobin (Δ[HHb], expressed in percentage of arterial occlusion and considered an index of O 2 extraction), and total hemoglobin (Δ[THb]) concentrations of the vastus lateralis muscle were continuously monitored by near-infrared spectroscopy. The metabolic efficiency of the contractions was calculated as the average force/Δ[HHb] avg ratio. Cohen's effect sizes (ES) ± 90% confidence limits were used to estimate IPC-induced changes and sex differences. IPC increased total muscular force in males only (13.0%, ES 0.64, 0.37;0.90), and this change was greater than in females (10.4% difference, ES 0.40, 0.10;0.70). Percent force decrement was only attenuated in females (-19.8%, ES -0.38, -0.77;0.01), which was clearly different than males (sex difference: ES 0.45, -0.16;1.07). IPC also induced different changes between sexes for average muscle O 2 uptake in set 2 (males: 6.4% vs. females: -16.7%, ES 0.21, -0.18;0.60), set 3 (males: 7.0% vs. females: -44.4%, ES 0.56, -0.17;1.29), set 4 (males: 9.1% vs. females: -40.2%, ES 0.51, -0.10;1.13), and set 5 (males: 10.2% vs. females: -40.4%, ES 0.52, -0.04;1.09). However, metabolic efficiency was not meaningfully different between conditions and sexes. IPC increased muscle blood volume (↑[THb]) at rest and during recovery between sets, to the same extent in both sexes. Despite a similar IPC-induced initial increase in O 2 delivery in both sexes, males displayed greater peripheral O 2 extraction and greater strength enhancement. This ergogenic effect appears to be mediated in part via an up regulated oxidative function in males. We conclude that strength-trained males might benefit more from IPC than their female counterparts during repeated, maximal efforts.

A Novel Method for Assessing Sex-Specific and Genotype-Specific Response to Injury in Astrocyte Culture

PubMed Central

Liu, Mingyue; Oyarzabal, Esteban; Yang, Rui; Murphy, Stephanie J; Hurn, Patricia D.

2008-01-01

Female astrocytes sustain less cell death from oxygen-glucose deprivation (OGD) than male astrocytes. Arimidex, an aromatase inhibitor, abolishes these sex differences. To verify sex-dependent differences in P450 aromatase function in astrocyte cell death following OGD, we developed a novel method that uses sex-specific and genotype-specific single pup primary astrocyte cultures from wild-type (WT) and aromatase-knockout (ArKO) mice. After determining sex by external and internal examination as well as PCR and genotype by PCR amplification of tail cDNA, we established cultures from 1−3 day-old male and female, WT and ArKO mice pups and grew them to confluence in estrogen-free media. Cell death was measured by lactate dehydrogenase (LDH) assay. Our study shows that, while WT female astrocytes are more resistant to OGD than WT male cells, sex differences disappear in ArKO cells. Cell death is significantly increased in ArKO compared to WT in female astrocytes but not male cells. Therefore, P450 aromatase appears to be essential in endogenous neuroprotection in females, and this finding may have clinical implications. This innovative technique may also be applied to other in vitro studies of sex-related functional differences. PMID:18436308

Gestational Dietary Protein Is Associated with Sex Specific Decrease in Blood Flow, Fetal Heart Growth and Post-Natal Blood Pressure of Progeny

PubMed Central

2015-01-01

Study Overview The incidence of adverse pregnancy outcomes is higher in pregnancies where the fetus is male. Sex specific differences in feto-placental perfusion indices identified by Doppler assessment have recently been associated with placental insufficiency and fetal growth restriction. This study aims to investigate sex specific differences in placental perfusion and to correlate these changes with fetal growth. It represents the largest comprehensive study under field conditions of uterine hemodynamics in a monotocous species, with a similar long gestation period to the human. Primiparous 14mo heifers in Australia (n=360) and UK (n=180) were either individually or group fed, respectively, diets with differing protein content (18, 14, 10 or 7% crude protein (CP)) from 60d prior to 98 days post conception (dpc). Fetuses and placentae were excised at 98dpc (n = 48). Fetal development an median uterine artery blood flow were assessed monthly from 36dpc until term using B-mode and Doppler ultrasonography. MUA blood flow to the male feto-placental unit increased in early pregnancy associated with increased fetal growth. Protein restriction before and shortly after conception (-60d up to 23dpc) increased MUA diameter and indices of velocity during late pregnancy, reduced fetal heart weight in the female fetus and increased heart rate at birth, but decreased systolic blood pressure at six months of age. Conclusion and Significance Sex specific differences both in feto-placental Doppler perfusion indices and response of these indices to dietary perturbations were observed. Further, maternal diet affected development of fetal cardiovascular system associated with altered fetal haemodynamics in utero, with such effects having a sex bias. The results from this study provide further insight into the gender specific circulatory differences present in the fetal period and developing cardiovascular system. PMID:25915506

Not all sex ratios are equal: the Fisher condition, parental care and sexual selection.

PubMed

Jennions, Michael D; Fromhage, Lutz

2017-09-19

The term 'sex roles' encapsulates male-female differences in mate searching, competitive traits that increase mating/fertilization opportunities, choosiness about mates and parental care. Theoretical models suggest that biased sex ratios drive the evolution of sex roles. To model sex role evolution, it is essential to note that in most sexually reproducing species (haplodiploid insects are an exception), each offspring has one father and one mother. Consequently, the total number of offspring produced by each sex is identical, so the mean number of offspring produced by individuals of each sex depends on the sex ratio (Fisher condition). Similarly, the total number of heterosexual matings is identical for each sex. On average, neither sex can mate nor breed more often when the sex ratio is even. But equally common in which sex ratio? The Fisher condition only applies to some reproductive measures (e.g. lifetime offspring production or matings) for certain sex ratios (e.g. operational or adult sex ratio; OSR, ASR). Here, we review recent models that clarify whether a biased OSR, ASR or sex ratio at maturation (MSR) have a causal or correlational relationship with the evolution of sex differences in parental care and competitive traits-two key components of sex roles. We suggest that it is more fruitful to understand the combined effect of the MSR and mortality rates while caring and competing than that of the ASR itself. In short, we argue that the ASR does not have a causal role in the evolution of parental care. We point out, however, that the ASR can be a cue for adaptive phenotypic plasticity in how each sex invests in parental care.This article is part of the themed issue 'Adult sex ratios and reproductive decisions: a critical re-examination of sex differences in human and animal societies'. © 2017 The Author(s).

Sexually divergent induction of microglial-associated neuroinflammation with hippocampal aging.

PubMed

Mangold, Colleen A; Wronowski, Benjamin; Du, Mei; Masser, Dustin R; Hadad, Niran; Bixler, Georgina V; Brucklacher, Robert M; Ford, Matthew M; Sonntag, William E; Freeman, Willard M

2017-07-21

The necessity of including both males and females in molecular neuroscience research is now well understood. However, there is relatively limited basic biological data on brain sex differences across the lifespan despite the differences in age-related neurological dysfunction and disease between males and females. Whole genome gene expression of young (3 months), adult (12 months), and old (24 months) male and female C57BL6 mice hippocampus was analyzed. Subsequent bioinformatic analyses and confirmations of age-related changes and sex differences in hippocampal gene and protein expression were performed. Males and females demonstrate both common expression changes with aging and marked sex differences in the nature and magnitude of the aging responses. Age-related hippocampal induction of neuroinflammatory gene expression was sexually divergent and enriched for microglia-specific genes such as complement pathway components. Sexually divergent C1q protein expression was confirmed by immunoblotting and immunohistochemistry. Similar patterns of cortical sexually divergent gene expression were also evident. Additionally, inter-animal gene expression variability increased with aging in males, but not females. These findings demonstrate sexually divergent neuroinflammation with aging that may contribute to sex differences in age-related neurological diseases such as stroke and Alzheimer's, specifically in the complement system. The increased expression variability in males suggests a loss of fidelity in gene expression regulation with aging. These findings reveal a central role of sex in the transcriptomic response of the hippocampus to aging that warrants further, in depth, investigations.

Increased postflight carotid artery stiffness and inflight insulin resistance resulting from 6-mo spaceflight in male and female astronauts.

PubMed

Hughson, Richard L; Robertson, Andrew D; Arbeille, Philippe; Shoemaker, J Kevin; Rush, James W E; Fraser, Katelyn S; Greaves, Danielle K

2016-03-01

Removal of the normal head-to-foot gravity vector and chronic weightlessness during spaceflight might induce cardiovascular and metabolic adaptations related to changes in arterial pressure and reduction in physical activity. We tested hypotheses that stiffness of arteries located above the heart would be increased postflight, and that blood biomarkers inflight would be consistent with changes in vascular function. Possible sex differences in responses were explored in four male and four female astronauts who lived on the International Space Station for 6 mo. Carotid artery distensibility coefficient (P = 0.005) and β-stiffness index (P = 0.006) reflected 17-30% increases in arterial stiffness when measured within 38 h of return to Earth compared with preflight. Spaceflight-by-sex interaction effects were found with greater changes in β-stiffness index in women (P = 0.017), but greater changes in pulse wave transit time in men (P = 0.006). Several blood biomarkers were changed from preflight to inflight, including an increase in an index of insulin resistance (P < 0.001) with a spaceflight-by-sex term suggesting greater change in men (P = 0.034). Spaceflight-by-sex interactions for renin (P = 0.016) and aldosterone (P = 0.010) indicated greater increases in women than men. Six-month spaceflight caused increased arterial stiffness. Altered hydrostatic arterial pressure gradients as well as changes in insulin resistance and other biomarkers might have contributed to alterations in arterial properties, including sex differences between male and female astronauts. Copyright © 2016 the American Physiological Society.

Ninety-day toxicity evaluation of 1,3,5-trinitrobenzene (Tnb) in Peromyscus leucopus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reddy, T.V.; Torsella, J.; Daniel, F.B.

1995-12-31

The subchronic toxicity of TNB in P. leucopus was evaluated by feeding Certified Rodent Diet 5002 supplemented with TNB (0, 150, 375, and 750 mg of TNB/kg diet), for 90 days. The food and water consumption was not significantly different between dose groups (for either sex). The calculated average daily TNB intake for female and male P. leucopus respectively, was 0, 20, 65, 108 and 0, 23, 67, and 113 mg/kg body weight (BW). There were no differences in the absolute body weights between sexes as well as between dose groups. Similarly, the organ weights (absolute and relative) did notmore » differ significantly between the dose groups (in both sexes) with an exception of male P. leucopus group receiving 750 mg TNB diet. In this group the spleen weights, both absolute and relative (g/100 g bw), were increased significantly. A significant increase in white blood cells and reticulocytes were detected. In addition, histopathological examinations in the aforementioned dose group revealed erythroid cell hyperplasia (spleen) and seminiferous tubular degeneration (testes). Although not significant, an increase in methemoglobin levels with an increased dose was evident. When the TNB concentration in the diet was increased to 1,200 and 1,800 mg/kg (used in the range finding study), the above indicated effects were much more prominent and were seen in both sexes. From this study a NOAEL of 20 mg/day/kg for female and 23 mg/day/kg for male is suggested.« less

The Long and the Short of It: No Dietary Specialisation between Male and Female Western Sandpipers Despite Strong Bill Size Dimorphism

PubMed Central

Franks, Samantha E.; Fernández, Guillermo; Hodkinson, David J.; Kyser, T. Kurt; Lank, David B.

2013-01-01

Many bird species show spatial or habitat segregation of the sexes during the non-breeding season. One potential ecological explanation is that differences in bill morphology favour foraging niche specialisation and segregation. Western sandpipers Calidris mauri have pronounced bill size dimorphism, with female bills averaging 15% longer than those of males. The sexes differ in foraging behaviour and exhibit partial latitudinal segregation during the non-breeding season, with males predominant in the north and females in the south. Niche specialisation at a local scale might account for this broad geographic pattern, and we investigated whether longer-billed females and shorter-billed males occupy different foraging niches at 16 sites across the non-breeding range. We used stable-nitrogen (δ15N) isotope analysis of whole blood to test for dietary specialisation according to bill length and sex. Stable-nitrogen isotope ratios increase with trophic level. We predicted that δ15N values would increase with bill length and would be higher for females, which use a greater proportion of foraging behaviour that targets higher-trophic level prey. We used stable-carbon (δ13C) isotope analysis to test for habitat segregation according to bill length and sex. Stable-carbon isotope ratios vary between marine- and freshwater-influenced habitats. We predicted that δ13C values would differ between males and females if the sexes segregate between habitat types. Using a model selection approach, we found little support for a relationship between δ15N and either bill length or sex. There was some indication, however, that more marine δ13C values occur with shorter bill lengths. Our findings provide little evidence that male and female western sandpipers exhibit dietary specialisation as a function of their bill size, but indicate that the sexes may segregate in different habitats according to bill length at some non-breeding sites. Potential ecological factors underlying habitat segregation between sexes include differences in preferred habitat type and predation risk. PMID:24260305

Sex in an Evolutionary Perspective: Just Another Reaction Norm

PubMed Central

Nylin, Sören

2010-01-01

It is common to refer to all sorts of clear-cut differences between the sexes as something that is biologically almost inevitable. Although this does not reflect the status of evolutionary theory on sex determination and sexual dimorphism, it is probably a common view among evolutionary biologists as well, because of the impact of sexual selection theory. To get away from thinking about biological sex and traits associated with a particular sex as something static, it should be recognized that in an evolutionary perspective sex can be viewed as a reaction norm, with sex attributes being phenotypically plastic. Sex determination itself is fundamentally plastic, even when it is termed “genetic”. The phenotypic expression of traits that are statistically associated with a particular sex always has a plastic component. This plasticity allows for much more variation in the expression of traits according to sex and more overlap between the sexes than is typically acknowledged. Here we review the variation and frequency of evolutionary changes in sex, sex determination and sex roles and conclude that sex in an evolutionary time-frame is extremely variable. We draw on recent findings in sex determination mechanisms, empirical findings of morphology and behaviour as well as genetic and developmental models to explore the concept of sex as a reaction norm. From this point of view, sexual differences are not expected to generally fall into neat, discrete, pre-determined classes. It is important to acknowledge this variability in order to increase objectivity in evolutionary research. PMID:21170116

Sex and Gender Differences in Risk, Pathophysiology and Complications of Type 2 Diabetes Mellitus.

PubMed

Kautzky-Willer, Alexandra; Harreiter, Jürgen; Pacini, Giovanni

2016-06-01

The steep rise of type 2 diabetes mellitus (T2DM) and associated complications go along with mounting evidence of clinically important sex and gender differences. T2DM is more frequently diagnosed at lower age and body mass index in men; however, the most prominent risk factor, which is obesity, is more common in women. Generally, large sex-ratio differences across countries are observed. Diversities in biology, culture, lifestyle, environment, and socioeconomic status impact differences between males and females in predisposition, development, and clinical presentation. Genetic effects and epigenetic mechanisms, nutritional factors and sedentary lifestyle affect risk and complications differently in both sexes. Furthermore, sex hormones have a great impact on energy metabolism, body composition, vascular function, and inflammatory responses. Thus, endocrine imbalances relate to unfavorable cardiometabolic traits, observable in women with androgen excess or men with hypogonadism. Both biological and psychosocial factors are responsible for sex and gender differences in diabetes risk and outcome. Overall, psychosocial stress appears to have greater impact on women rather than on men. In addition, women have greater increases of cardiovascular risk, myocardial infarction, and stroke mortality than men, compared with nondiabetic subjects. However, when dialysis therapy is initiated, mortality is comparable in both males and females. Diabetes appears to attenuate the protective effect of the female sex in the development of cardiac diseases and nephropathy. Endocrine and behavioral factors are involved in gender inequalities and affect the outcome. More research regarding sex-dimorphic pathophysiological mechanisms of T2DM and its complications could contribute to more personalized diabetes care in the future and would thus promote more awareness in terms of sex- and gender-specific risk factors.

Sex and Gender Differences in Risk, Pathophysiology and Complications of Type 2 Diabetes Mellitus

PubMed Central

Harreiter, Jürgen; Pacini, Giovanni

2016-01-01

The steep rise of type 2 diabetes mellitus (T2DM) and associated complications go along with mounting evidence of clinically important sex and gender differences. T2DM is more frequently diagnosed at lower age and body mass index in men; however, the most prominent risk factor, which is obesity, is more common in women. Generally, large sex-ratio differences across countries are observed. Diversities in biology, culture, lifestyle, environment, and socioeconomic status impact differences between males and females in predisposition, development, and clinical presentation. Genetic effects and epigenetic mechanisms, nutritional factors and sedentary lifestyle affect risk and complications differently in both sexes. Furthermore, sex hormones have a great impact on energy metabolism, body composition, vascular function, and inflammatory responses. Thus, endocrine imbalances relate to unfavorable cardiometabolic traits, observable in women with androgen excess or men with hypogonadism. Both biological and psychosocial factors are responsible for sex and gender differences in diabetes risk and outcome. Overall, psychosocial stress appears to have greater impact on women rather than on men. In addition, women have greater increases of cardiovascular risk, myocardial infarction, and stroke mortality than men, compared with nondiabetic subjects. However, when dialysis therapy is initiated, mortality is comparable in both males and females. Diabetes appears to attenuate the protective effect of the female sex in the development of cardiac diseases and nephropathy. Endocrine and behavioral factors are involved in gender inequalities and affect the outcome. More research regarding sex-dimorphic pathophysiological mechanisms of T2DM and its complications could contribute to more personalized diabetes care in the future and would thus promote more awareness in terms of sex- and gender-specific risk factors. PMID:27159875

Sex differences and HIV risk behaviors: the interaction between the experience of multiple types of abuse and self-restraint on HIV risk behaviors.

PubMed

Conrad, Selby M; Swenson, Rebecca R; Hancock, Evan; Brown, Larry K

2014-01-01

Adolescents with abuse histories have been shown to be at increased risk to acquire human immunodeficiency virus and sexually transmitted infections. In addition, teens with lower levels of self-restraint or higher levels of distress, such as those with psychiatric concerns, have also demonstrated increased sexual risk behaviors. This study explored sex differences in sexual risk behaviors among a sample of adolescents in a therapeutic/alternative high school setting. Moderated regression analysis showed that a lower level of self-restraint was associated with sexual risk behaviors in boys but not in girls. Rather, the interaction of self-restraint and multiple types of abuse was associated with greater sex risk within girls in this sample. Results suggest that girls and boys with abuse histories and low levels of self-restraint may have different intervention needs related to sexual risk behaviors.

Drinking and Stress: An Examination of Sex and Stressor Differences Using IVR-Based Daily Data

PubMed Central

Ayer, Lynsay A.; Harder, Valerie S.; Rose, Gail L.; Helzer, John E.

2010-01-01

Background Research on the relation of stress to alcohol consumption is inconsistent regarding the direction of effects, and this association has been shown to vary by sex and type of stress. We sought to build upon the stress-drinking literature by examining the direction of the stress-drinking association over time as well as sex and stressor differences using daily data. Method 246 heavy drinking adults (67% men) ages 21 to 82 reported daily stress levels and alcohol consumption over 180 days using Interactive Voice Response (IVR). Baseline daily hassles were examined as an alternative measure of stress. Generalized estimating equations (GEEs) were conducted to test the stress-drinking association accounting for alcohol dependency at baseline and sex and stressor type as moderators. Results IVR daily stress predicted increased alcohol consumption the following day, whereas baseline level of daily hassles did not. Examining the opposite direction of effects, IVR ratings of daily alcohol consumption predicted decreased next-day stress. Stress predicted higher alcohol consumption the next day for men but there was no significant association for women. For both sexes, drinking predicted decreased stress the next day, but this effect was stronger for women. Conclusions This study generally supported the drinking to cope and self-medication hypotheses, with findings that increased stress led to increased drinking. The time-varying relation between stress and alcohol appears to be sex- and measure- specific, however. Therefore, interventions targeted at stress management found to be effective for one sex should not be presumed to be applicable to the other. PMID:21146940

Between-year variation in population sex ratio increases with complexity of the breeding system in Hymenoptera.

PubMed

Kümmerli, Rolf; Keller, Laurent

2011-06-01

While adaptive adjustment of sex ratio in the function of colony kin structure and food availability commonly occurs in social Hymenoptera, long-term studies have revealed substantial unexplained between-year variation in sex ratio at the population level. In order to identify factors that contribute to increased between-year variation in population sex ratio, we conducted a comparative analysis across 47 Hymenoptera species differing in their breeding system. We found that between-year variation in population sex ratio steadily increased as one moved from solitary species, to primitively eusocial species, to single-queen eusocial species, to multiple-queen eusocial species. Specifically, between-year variation in population sex ratio was low (6.6% of total possible variation) in solitary species, which is consistent with the view that in solitary species, sex ratio can vary only in response to fluctuations in ecological factors such as food availability. In contrast, we found significantly higher (19.5%) between-year variation in population sex ratio in multiple-queen eusocial species, which supports the view that in these species, sex ratio can also fluctuate in response to temporal changes in social factors such as queen number and queen-worker control over sex ratio, as well as factors influencing caste determination. The simultaneous adjustment of sex ratio in response to temporal fluctuations in ecological and social factors seems to preclude the existence of a single sex ratio optimum. The absence of such an optimum may reflect an additional cost associated with the evolution of complex breeding systems in Hymenoptera societies.

The Evolution of Sex Chromosomes and Dosage Compensation in Plants

PubMed Central

Shearn, Rylan; Marais, Gabriel AB

2017-01-01

Plant sex chromosomes can be vastly different from those of the few historical animal model organisms from which most of our understanding of sex chromosome evolution is derived. Recently, we have seen several advancements from studies on green algae, brown algae, and land plants that are providing a broader understanding of the variable ways in which sex chromosomes can evolve in distant eukaryotic groups. Plant sex-determining genes are being identified and, as expected, are completely different from those in animals. Species with varying levels of differentiation between the X and Y have been found in plants, and these are hypothesized to be representing different stages of sex chromosome evolution. However, we are also finding that sex chromosomes can remain morphologically unchanged over extended periods of time. Where degeneration of the Y occurs, it appears to proceed similarly in plants and animals. Dosage compensation (a phenomenon that compensates for the consequent loss of expression from the Y) has now been documented in a plant system, its mechanism, however, remains unknown. Research has also begun on the role of sex chromosomes in sexual conflict resolution, and it appears that sex-biased genes evolve similarly in plants and animals, although the functions of these genes remain poorly studied. Because the difficulty in obtaining sex chromosome sequences is increasingly being overcome by methodological developments, there is great potential for further discovery within the field of plant sex chromosome evolution. PMID:28391324

Influence of knee joint position and sex on vastus medialis regional architecture.

PubMed

Gallina, Alessio; Render, Jacqueline N; Santos, Jacquelyne; Shah, Hershal; Taylor, Dayna; Tomlin, Travis; Garland, S Jayne

2018-06-01

Ultrasound imaging was used to investigate vastus medialis (VM) architecture in 10 males and 10 females at different knee angles. Increase in muscle thickness occurs predominantly when the knee angle is changed from 0° (full extension) and 45° (p < 0.05); increases in VM pennation angle can be predominantly observed between 45° and 90° (p < 0.05). Sex differences in the VM architecture can be observed in the distal (p < 0.01) but not in the proximal region of the muscle (p > 0.11).

Sex differences and the roles of sex steroids in apoptosis of sexually dimorphic nuclei of the preoptic area in postnatal rats.

PubMed

Tsukahara, S

2009-03-01

The brain contains several sexually dimorphic nuclei that exhibit sex differences with respect to cell number. It is likely that the control of cell number by apoptotic cell death in the developing brain contributes to creating sex differences in cell number in sexually dimorphic nuclei, although the mechanisms responsible for this have not been determined completely. The milieu of sex steroids in the developing brain affects sexual differentiation in the brain. The preoptic region of rats has two sexually dimorphic nuclei. The sexually dimorphic nucleus of the preoptic area (SDN-POA) has more neurones in males, whereas the anteroventral periventricular nucleus (AVPV) has a higher cell density in females. Sex differences in apoptotic cell number arise in the SDN-POA and AVPV of rats in the early postnatal period, and an inverse correlation exists between sex differences in apoptotic cell number and the number of living cells in the mature period. The SDN-POA of postnatal male rats exhibits a higher expression of anti-apoptotic Bcl-2 and lower expression of pro-apoptotic Bax compared to that in females and, as a potential result, apoptotic cell death via caspase-3 activation more frequently occurs in the SDN-POA of females. The patterns of expression of Bcl-2 and Bax in the SDN-POA of postnatal female rats are changed to male-typical ones by treatment with oestrogen, which is normally synthesised from testicular androgen and affects the developing brain in males. In the AVPV of postnatal rats, apoptotic regulation also differs between the sexes, although Bcl-2 expression is increased and Bax expression and caspase-3 activity are decreased in females. The mechanisms of apoptosis possibly contributing to the creation of sex differences in cell number and the roles of sex steroids in apoptosis are discussed.

Sex-different hepaticglycogen content and glucose output in rats

PubMed Central

2010-01-01

Background Genes involved in hepatic metabolism have a sex-different expression in rodents. To test whether male and female rat livers differ regarding lipid and carbohydrate metabolism, whole-genome transcript profiles were generated and these were complemented by measurements of hepatic lipid and glycogen content, fatty acid (FA) oxidation rates and hepatic glucose output (HGO). The latter was determined in perfusates from in situ perfusion of male and female rat livers. These perfusates were also analysed using nuclear magnetic resonance (NMR) spectroscopy to identify putative sex-differences in other liver-derived metabolites. Effects of insulin were monitored by analysis of Akt-phosphorylation, gene expression and HGO after s.c. insulin injections. Results Out of approximately 3 500 gene products being detected in liver, 11% were significantly higher in females, and 11% were higher in males. Many transcripts for the production of triglycerides (TG), cholesterol and VLDL particles were female-predominant, whereas genes for FA oxidation, gluconeogenesis and glycogen synthesis were male-predominant. Sex-differences in mRNA levels related to metabolism were more pronounced during mild starvation (12 h fasting), as compared to the postabsorptive state (4 h fasting). No sex-differences were observed regarding hepatic TG content, FA oxidation rates or blood levels of ketone bodies or glucose. However, males had higher hepatic glycogen content and higher HGO, as well as higher ratios of insulin to glucagon levels. Based on NMR spectroscopy, liver-derived lactate was also higher in males. HGO was inhibited by insulin in parallel with increased phosphorylation of Akt, without any sex-differences in insulin sensitivity. However, the degree of Thr172-phosphorylated AMP kinase (AMPK) was higher in females, indicating a higher degree of AMPK-dependent actions. Conclusions Taken together, males had higher ratios of insulin to glucagon levels, higher levels of glycogen, lower degree of AMPK phosphorylation, higher expression of gluconeogenic genes and higher hepatic glucose output. Possibly these sex-differences reflect a higher ability for the healthy male rat liver to respond to increased energy demands. PMID:20863371

Exploring mechanisms underlying sex-specific differences in mortality of Lake Michigan bloaters

USGS Publications Warehouse

Bunnell, D.B.; Madenjian, C.P.; Rogers, M.W.; Holuszko, J.D.; Begnoche, L.J.

2012-01-01

Sex-specific differences in mortality rates have been observed among freshwater and marine fish taxa, and underlying mechanisms can include sex-specific differences in (1) age at maturity, (2) growth rate, or (3) activity or behavior during the spawning period. We used a long-term (1973–2009) Lake Michigan data set to evaluate whether there were sex-specific differences in catch per unit effort, mortality, age at maturity, and length at age in bloaters Coregonus hoyi. Because bloater population biomass varied 200-fold during the years analyzed, we divided the data into three periods: (1) 1973–1982 (low biomass), (2) 1983–1997 (high biomass), and (3) 1998–2009 (low biomass). Mortality was higher for males than for females in periods 2 and 3; the average instantaneous total mortality rate (Z) over these two periods was 0.71 for males and 0.57 for females. Length at age was slightly greater (2–6%) for females than for males in different age-classes (3–6 years) during each period. Age at maturity was earlier for males than for females in periods 1 and 2, but the mean difference was only 0.2–0.4 years. To test the hypothesis that somatic lipids declined more in males than in females during spawning (perhaps due to increased activity or reduced feeding), we estimated sex-specific percent somatic lipids for fish sampled in 2005–2006 and 2007–2008. During 2005–2006, somatic lipids declined from prespawning to postspawning for males but were unchanged for females. During 2007–2008, however, somatic lipids were unchanged for males, whereas they increased for females. We found that sex-specific differences in Z occurred in the Lake Michigan bloater population, but our hypotheses that sex-specific differences in maturity and growth could explain this pattern were generally unsupported. Our hypothesis that somatic lipids in males declined during spawning at a faster rate than in females will require additional research to clarify its importance.

Race differences in obesity and its relationship to the sex hormone milieu.

PubMed

Perry, Arlette C; Martin, Lorena

2014-09-01

A sexual dimorphism exists in which increased abdominal and visceral adipose tissue (VAT) - found in women and marked by low sex hormone binding globulin (SHBG) and high bioavailable testosterone (BT) - is related to the metabolic risk profile. In men, increased BT is related to decreased abdominal obesity and a decrease in the metabolic risk profile. In women, race differences have been found in androgenic sex steroids including SHBG and BT as well as central fat distribution, creating inherently greater metabolic risk for certain populations. Estrogen and estrogen receptor isoforms play a role in fat deposition and distribution and may influence the changes that occur during the menopausal transition. Androgenic sex steroids serve a mediating role, influencing VAT accumulation and its associated metabolic risk factors while VAT also serves a mediating role influencing the androgenic sex steroid-metabolic risk relationship in women. Furthermore, androgenic sex steroids and VAT may independently contribute to the variance in several metabolic variables associated with cardiovascular disease, type 2 diabetes, and their antecedent conditions such as the metabolic syndrome. Race has been shown to modify the relationship between androgenic sex steroids and metabolic variables associated with risk for diabetes in Black and White women. Further research is warranted to examine the mechanisms involved in race differences. Total adiposity and central fat distribution in accordance with changes in the hormone and metabolic milieu influence breast cancer risk, which varies by race and menopausal status. These findings have broader implications for the study of health promotion/disease prevention in women.

Sex differences in the risk of rapid cycling and other indicators of adverse illness course in patients with bipolar I and II disorder.

PubMed

Erol, Almila; Winham, Stacey J; McElroy, Susan L; Frye, Mark A; Prieto, Miguel L; Cuellar-Barboza, Alfredo B; Fuentes, Manuel; Geske, Jennifer; Mori, Nicole; Biernacka, Joanna M; Bobo, William V

2015-09-01

To examine the independent effects of sex on the risk of rapid cycling and other indicators of adverse illness course in patients with bipolar I disorder (BP-I) or bipolar II disorder (BP-II). We analyzed data from the first 1,225 patients enrolled in the Mayo Clinic Individualized Medicine Biobank for Bipolar Disorder. Demographic and clinical variables were ascertained using standardized questionnaires; height and weight were assessed to determine body mass index (BMI). Rates of rapid cycling, cycle acceleration, and increased severity of mood episodes over time were compared between women and men overall and within subgroups defined by bipolar disorder subtype (BP-I or BP-II). Multiple logistic regression analysis was used to assess the independent effect of sex on the risk of these indicators of adverse illness course. Women had significantly higher rates of rapid cycling than men. Overall rates of rapid cycling were higher in patients with BP-II than BP-I; and sex differences in the rate of rapid cycling were more pronounced in patients with BP-II than BP-I, although the power to detect statistically significant differences was reduced due to the lower sample size of subjects with BP-II. Female sex was a significant predictor of rapid cycling, cycle acceleration, and increased severity of mood episodes over time after adjusting for age, bipolar disorder subtype, BMI, having any comorbid psychiatric disorder, and current antidepressant use. Female sex was associated with significantly higher risk of rapid cycling, cycle acceleration, and increased severity of mood episodes over time in a sample of 1,225 patients with bipolar disorders. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Sensitivity of the prefrontal GABAergic system to chronic stress in male and female mice: Relevance for sex differences in stress-related disorders.

PubMed

Shepard, Ryan; Page, Chloe E; Coutellier, Laurence

2016-09-22

Stress-induced modifications of the prefrontal cortex (PFC) are believed to contribute to the onset of mood disorders, such as depression and anxiety, which are more prevalent in women. In depression, the PFC is hypoactive; however the origin of this hypoactivity remains unclear. Possibly, stress could impact the prefrontal GABAergic inhibitory system that, as a result, impairs the functioning of downstream limbic structures controlling emotions. Preclinical evidence indicates that the female PFC is more sensitive to the effects of stress. These findings suggest that exposure to stress could lead to sex-specific alterations in prefrontal GABAergic signaling, which contribute to sex-specific abnormal functioning of limbic regions. These limbic changes could promote the onset of depressive and anxiety behaviors in a sex-specific manner, providing a possible mechanism mediating sex differences in the clinical presentation of stress-related mood disorders. We addressed this hypothesis using a mouse model of stress-induced depressive-like behaviors: the unpredictable chronic mild stress (UCMS) paradigm. We observed changes in prefrontal GABAergic signaling after exposure to UCMS most predominantly in females. Increased parvalbumin (PV) expression and decreased prefrontal neuronal activity were correlated in females with severe emotionality deficit following UCMS, and with altered activity of the amygdala. In males, small changes in emotionality following UCMS were associated with minor changes in prefrontal PV expression, and with hypoactivity of the nucleus accumbens. Our data suggest that prefrontal hypoactivity observed in stress-related mood disorders could result from stress-induced increases in PV expression, particularly in females. This increased vulnerability of the female prefrontal PV system to stress could underlie sex differences in the prevalence and symptomatology of stress-related mood disorders. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

Activation patterns of vasopressinergic and oxytocinergic brain regions following social play exposure in juvenile male and female rats.

PubMed

Reppucci, C J; Gergely, C K; Veenema, A H

2018-02-09

Social play is a highly rewarding and motivated behavior predominately displayed by juveniles and expressed by nearly all mammalian species. Prior work suggested that the vasopressin (AVP) and oxytocin (OT) systems can regulate the expression of social play in sex-specific ways. Here we investigated whether there are sex differences in the recruitment of vasopressinergic and oxytocinergic brain regions following social play exposure in juvenile rats. Single-housed rats were allowed to play, in their home cage, with an age- and sex-matched unfamiliar conspecific for 10 min, or received similar handling but no partner. Double-labeled fluorescent immunohistochemistry for Fos and either AVP or OT was completed in adjacent series of tissue to determine recruitment of AVP- and OT-immunoreactive neurons in response to social play. Exposure to social play did not increase recruitment of AVP or OT neurons in the supraoptic (SO) or paraventricular (PVH) hypothalamic nuclei of either sex compared to the no-play control condition. Interestingly, there was a robust sex difference in SO recruitment, irrespective of social play condition, with males exhibiting twice the recruitment of SO-AVP and SO-OT neurons compared to females. Lastly, exposure to social play increased recruitment of the posterior bed nuclei of the stria terminalis (pBST) and the posterodorsal medial amygdalar nucleus (MEApd) compared to the no-play control condition, and this effect was most pronounced in females. Our findings revealed sex differences in the recruitment of brain regions (i) independent of play condition (i.e., SO) possibly representing a sex difference in the baseline levels of AVP and OT signaling required for typical functioning and (ii) specific to play condition (i.e., pBST, MEApd). In sum, this study provides further evidence that the neural substrates underlying social play behavior are sex-specific. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Challenges and Opportunities for Research on Same-Sex Relationships

PubMed Central

Umberson, Debra; Thomeer, Mieke Beth; Kroeger, Rhiannon A.; Lodge, Amy Caroline; Xu, Minle

2014-01-01

Research on same-sex relationships has informed policy debates and legal decisions that greatly affect American families, yet the data and methods available to scholars studying same-sex relationships have been limited. In this article the authors review current approaches to studying same-sex relationships and significant challenges for this research. After exploring how researchers have dealt with these challenges in prior studies, the authors discuss promising strategies and methods to advance future research on same-sex relationships, with particular attention given to gendered contexts and dyadic research designs, quasi-experimental designs, and a relationship biography approach. Innovation and advances in the study of same-sex relationships will further theoretical and empirical knowledge in family studies more broadly and increase understanding of different-sex as well as same-sex relationships. PMID:25598552

Selection for sex in finite populations.

PubMed

Roze, D

2014-07-01

Finite population size generates interference between selected loci, which has been shown to favour increased rates of recombination. In this article, I present different analytical models exploring selection acting on a 'sex modifier locus' (that affects the relative investment into asexual and sexual reproduction) in a finite population. Two forms of selective forces act on the modifier: direct selection due to intrinsic costs associated with sexual reproduction and indirect selection generated by one or two other loci affecting fitness. The results show that indirect selective forces differ from those acting on a recombination modifier even in the case of a haploid population: in particular, a single selected locus generates indirect selection for sex, while two loci are required in the case of a recombination modifier. This effect stems from the fact that modifier alleles increasing sex escape more easily from low-fitness genetic backgrounds than alleles coding for lower rates of sex. Extrapolating the results from three-locus models to a large number of loci at mutation-selection balance indicates that in the parameter range where indirect selection is strong enough to outweigh a substantial cost of sex, interactions between selected loci have a stronger effect than the sum of individual effects of each selected locus. Comparisons with multilocus simulation results show that such extrapolations may provide correct predictions for the evolutionarily stable rate of sex, unless the cost of sex is high. © 2014 The Author. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

Drivers of protogynous sex change differ across spatial scales.

PubMed

Taylor, Brett M

2014-01-22

The influence of social demography on sex change schedules in protogynous reef fishes is well established, yet effects across spatial scales (in particular, the magnitude of natural variation relative to size-selective fishing effects) are poorly understood. Here, I examine variation in timing of sex change for exploited parrotfishes across a range of environmental, anthropogenic and geographical factors. Results were highly dependent on spatial scale. Fishing pressure was the most influential factor determining length at sex change at the within-island scale where a wide range of anthropogenic pressure existed. Sex transition occurred at smaller sizes where fishing pressure was high. Among islands, however, differences were overwhelmingly predicted by reefal-scale structural features, a pattern evident for all species examined. For the most abundant species, Chlorurus spilurus, length at sex change increased at higher overall densities and greater female-to-male sex ratios at all islands except where targeted by fishermen; here the trend was reversed. This implies differing selective pressures on adult individuals can significantly alter sex change dynamics, highlighting the importance of social structure, demography and the selective forces structuring populations. Considerable life-history responses to exploitation were observed, but results suggest potential fishing effects on demography may be obscured by natural variation at biogeographic scales.

Girls in the boat: Sex differences in rowing performance and participation.

PubMed

Keenan, Kevin G; Senefeld, Jonathon W; Hunter, Sandra K

2018-01-01

Men outperform women in many athletic endeavors due to physiological and anatomical differences (e.g. larger and faster muscle); however, the observed sex differences in elite athletic performance are typically larger than expected, and may reflect sex-related differences in opportunity or incentives. As collegiate rowing in the United States has been largely incentivized for women over the last 20 years, but not men, the purpose of this study was to examine sex differences in elite rowing performance over that timeframe. Finishing times from grand finale races for collegiate championship on-water performances (n = 480) and junior indoor performances (n = 1,280) were compared between men and women across 20 years (1997-2016), weight classes (heavy vs. lightweight) and finishing place. Participation of the numbers of men and women rowers were also quantified across years. Men were faster than women across all finishing places, weight classes and years of competition and performance declined across finishing place for both men and women (P<0.001). Interestingly, the reduction in performance time across finishing place was greater (P<0.001) for collegiate men compared to women in the heavyweight division. This result is opposite to other sports (e.g. running and swimming), and to lightweight rowing in this study, which provides women fewer incentives than in heavyweight rowing. Correspondingly, participation in collegiate rowing has increased by ~113 women per year (P<0.001), with no change (P = 0.899) for collegiate men. These results indicate that increased participation and incentives within collegiate rowing for women vs. men contribute to sex differences in athletic performance.

Girls in the boat: Sex differences in rowing performance and participation

PubMed Central

Senefeld, Jonathon W.; Hunter, Sandra K.

2018-01-01

Men outperform women in many athletic endeavors due to physiological and anatomical differences (e.g. larger and faster muscle); however, the observed sex differences in elite athletic performance are typically larger than expected, and may reflect sex-related differences in opportunity or incentives. As collegiate rowing in the United States has been largely incentivized for women over the last 20 years, but not men, the purpose of this study was to examine sex differences in elite rowing performance over that timeframe. Finishing times from grand finale races for collegiate championship on-water performances (n = 480) and junior indoor performances (n = 1,280) were compared between men and women across 20 years (1997–2016), weight classes (heavy vs. lightweight) and finishing place. Participation of the numbers of men and women rowers were also quantified across years. Men were faster than women across all finishing places, weight classes and years of competition and performance declined across finishing place for both men and women (P<0.001). Interestingly, the reduction in performance time across finishing place was greater (P<0.001) for collegiate men compared to women in the heavyweight division. This result is opposite to other sports (e.g. running and swimming), and to lightweight rowing in this study, which provides women fewer incentives than in heavyweight rowing. Correspondingly, participation in collegiate rowing has increased by ~113 women per year (P<0.001), with no change (P = 0.899) for collegiate men. These results indicate that increased participation and incentives within collegiate rowing for women vs. men contribute to sex differences in athletic performance. PMID:29352279

Reproduction reduces photosynthetic capacity in females of the subdioecious Honckenya peploides

NASA Astrophysics Data System (ADS)

Sánchez-Vilas, Julia; Retuerto, Rubén

2011-03-01

As a consequence of the different reproductive functions performed by the sexes, sexually dimorphic/polymorphic plants may exhibit gender-related variations in the energy and resources allocated to reproduction, and in the physiological processes that underlie these differences. This study investigated whether the sexes of the subdioecious plant Honckenya peploides differ in ecophysiological traits related to photosynthetic capacity and whether possible differences depend on reproductive status and on the plant's position (edge or centre) in the population. We registered in three sites in NW Spain, the sex and density of shoots of two segregated clumps of plants. These clumps represent an extreme case of sex-ratio variation across space, with separated single-sex clumps of plants. In two of these sites we measured photosynthetic efficiencies, chlorophyll content, and specific leaf areas. In females, reproduction reduced photochemical efficiency, chlorophyll content and increased the specific leaf area, which is a key leaf trait related to photosynthetic capacity. In males, no differences due to reproduction were detected. The position within the clump affected the specific leaf area of the shoots, with shoots growing at the edge having the lowest values, regardless of the sex. Finally, the effects of position in photosynthetic efficiency and chlorophyll content where highly variable among clumps. We conclude that the differential effects of reproduction on sexes may entail different costs that could be crucial in the outcome of interactions between them, contributing to their spatial segregation.

Sex differences in the effect of aging on dry eye disease.

PubMed

Ahn, Jong Ho; Choi, Yoon-Hyeong; Paik, Hae Jung; Kim, Mee Kum; Wee, Won Ryang; Kim, Dong Hyun

2017-01-01

Aging is a major risk factor in dry eye disease (DED), and understanding sexual differences is very important in biomedical research. However, there is little information about sex differences in the effect of aging on DED. We investigated sex differences in the effect of aging and other risk factors for DED. This study included data of 16,824 adults from the Korea National Health and Nutrition Examination Survey (2010-2012), which is a population-based cross-sectional survey. DED was defined as the presence of frequent ocular dryness or a previous diagnosis by an ophthalmologist. Basic sociodemographic factors and previously known risk factors for DED were included in the analyses. Linear regression modeling and multivariate logistic regression modeling were used to compare the sex differences in the effect of risk factors for DED; we additionally performed tests for interactions between sex and other risk factors for DED in logistic regression models. In our linear regression models, the prevalence of DED symptoms in men increased with age ( R =0.311, P =0.012); however, there was no association between aging and DED in women ( P >0.05). Multivariate logistic regression analyses showed that aging in men was not associated with DED (DED symptoms/diagnosis: odds ratio [OR] =1.01/1.04, each P >0.05), while aging in women was protectively associated with DED (DED symptoms/diagnosis: OR =0.94/0.91, P =0.011/0.003). Previous ocular surgery was significantly associated with DED in both men and women (men/women: OR =2.45/1.77 [DED symptoms] and 3.17/2.05 [DED diagnosis], each P <0.001). Tests for interactions of sex revealed significantly different aging × sex and previous ocular surgery × sex interactions ( P for interaction of sex: DED symptoms/diagnosis - 0.044/0.011 [age] and 0.012/0.006 [previous ocular surgery]). There were distinct sex differences in the effect of aging on DED in the Korean population. DED following ocular surgery also showed sexually different patterns. Age matching and sex matching are strongly recommended in further studies about DED, especially DED following ocular surgery.

Stability and change in same-sex attraction, experience, and identity by sex and age in a New Zealand birth cohort.

PubMed

Dickson, Nigel; van Roode, Thea; Cameron, Claire; Paul, Charlotte

2013-07-01

Gaps remain in knowledge of changes in sexual orientation past adolescence and early adulthood. A longitudinal study of a New Zealand birth cohort was used to examine differences by age and sex in change in sexual attraction between 21 (1993/1994) and 38 years (2010/2011), sexual experiences between 26 and 38 years, and sexual identity between 32 and 38 years. Any same-sex attraction was significantly more common among women than men at all ages. Among women, any same-sex attraction increased up to age 26 (from 8.8 to 16.6 %), then decreased slightly by age 38 (12.0 %); among men, prevalence was significantly higher at age 38 (6.5 %) than 21 (4.2 %), but not in the intermediate assessments. It is likely that the social environment becoming more tolerant was responsible for some of the changes. Same-sex attraction was much more common than same-sex experiences or a same-sex identity, especially among women, with no major sex differences in these latter dimensions. Women exhibited much greater change in sexual attraction between assessments than men; for change in experiences and identity, sex differences were less marked and not statistically confirmed. Changes in the respective dimensions appeared more likely among those initially with mixed attraction and experiences, and among those initially identifying as bisexual, but this did not account for the sex difference in likelihood of change. These results provide contemporary information about the extent and variation of reported sexual attraction, experiences, and identity that we show continues across early and mid-adulthood.

Selling sex in unsafe spaces: sex work risk environments in Phnom Penh, Cambodia

PubMed Central

2011-01-01

Background The risk environment framework provides a valuable but under-utilised heuristic for understanding environmental vulnerability to HIV and other sexually transmitted infections among female sex workers. Brothels have been shown to be safer than street-based sex work, with higher rates of consistent condom use and lower HIV prevalence. While entertainment venues are also assumed to be safer than street-based sex work, few studies have examined environmental influences on vulnerability to HIV in this context. Methods As part of the Young Women's Health Study, a prospective observational study of young women (15-29 years) engaged in sex work in Phnom Penh, we conducted in-depth interviews (n = 33) to explore vulnerability to HIV/STI and related harms. Interviews were conducted in Khmer by trained interviewers, transcribed and translated into English and analysed for thematic content. Results The intensification of anti-prostitution and anti-trafficking efforts in Cambodia has increased the number of women working in entertainment venues and on the street. Our results confirm that street-based sex work places women at risk of HIV/STI infection and identify significant environmental risks related to entertainment-based sex work, including limited access to condoms and alcohol-related intoxication. Our data also indicate that exposure to violence and interactions with the police are mediated by the settings in which sex is sold. In particular, transacting sex in environments such as guest houses where there is little or no oversight in the form of peer or managerial support or protection, may increase vulnerability to HIV/STI. Conclusions Entertainment venues may also provide a high risk environment for sex work. Our results indicate that strategies designed to address HIV prevention among brothel-based FSWs in Cambodia have not translated well to street and entertainment-based sex work venues in which increasing numbers of women are working. There is an urgent need for targeted interventions, supported by legal and policy reforms, designed to reduce the environmental risks of sex work in these settings. Future research should seek to investigate sex work venues as risk environments, explore the role of different business models in mediating these environments, and identify and quantify exposure to risk in different occupational settings. PMID:22099449

Sex differences in regulatory cells in experimental stroke.

PubMed

Seifert, Hilary A; Benedek, Gil; Liang, Jian; Nguyen, Ha; Kent, Gail; Vandenbark, Arthur A; Saugstad, Julie A; Offner, Halina

2017-08-01

Stroke is the leading cause of disability in the United States. Sex differences, including smaller infarcts in females and greater involvement of immune-mediated inflammation in males may affect the efficacy of immune-modulating interventions. To address these differences, we sought to identify distinct stroke-modifying mechanisms in female vs. male mice. The current study demonstrated smaller infarcts and increased levels of regulatory CD19 + CD5 + CD1d hi B10 cells as well as anti-inflammatory CD11b + CD206 + microglia/macrophages in the ipsilateral vs. contralateral hemisphere of female but not male mice undergoing 60min middle cerebral artery occlusion followed by 96h of reperfusion. Moreover, female mice with MCAO had increased total spleen cell numbers but lower B10 levels in spleens. These results elucidate differing sex-dependent regulatory mechanisms that account for diminished stroke severity in females and underscore the need to test immune-modulating therapies for stroke in both males and females. Copyright © 2017 Elsevier Inc. All rights reserved.

Terminal Investment Strategies and Male Mate choice: Extreme Tests of Bateman.

PubMed

Andrade, Maydianne C B; Kasumovic, Michael M

2005-11-01

Bateman's principle predicts the intensity of sexual selection depends on rates of increase of fecundity with mating success for each sex (Bateman slopes). The sex with the steeper increase (usually males) is under more intense sexual selection and is expected to compete for access to the sex under less intense sexual selection (usually females). Under Bateman and modern refinements of his ideas, differences in parental investment are key to defining Bateman slopes and thus sex roles. Other theories predict sex differences in mating investment, or any expenditures that reduce male potential reproductive rate, can also control sex roles. We focus on sexual behaviour in systems where males have low paternal investment but frequently mate only once in their lifetimes, after which they are often killed by the female. Mating effort (=terminal investment) is high for these males, and many forms of investment theory might predict sex role reversal. We find no qualitative evidence for sex role reversal in a sample of spiders that show this extreme male investment pattern. We also present new data for terminally-investing redback spiders (Latrodectus hasselti). Bateman slopes are relatively steep for male redbacks, and, as predicted by Bateman, there is little evidence for role reversal. Instead, males are competitive and show limited choosiness despite wide variation in female reproductive value. This study supports the proposal that high male mating investment coupled with low parental investment may predispose males to choosiness but will not lead to role reversal. We support the utility of using Bateman slopes to predict sex roles, even in systems with extreme male mating investment.

A neuropsychological study of older adult first-time sex offenders.

PubMed

Rodriguez, Marcelo; Boyce, Philip; Hodges, John

2017-04-01

The issue of whether sex offenders have cognitive deficits remains controversial. The objective of this study was to compare the neuropsychological function of older adult first time sex-offenders (FTSO), who had not previously been charged with a sexual offence prior to the age of 50, to historical long-term sex offenders (HSO) and non-sex offenders (NSO). The hypotheses were (a) that FTSO would demonstrate greater deficits in executive function, decision-making, and memory compared to non-sex offenders; and (b) the HSOs would present similar neuropsychological deficits to non-sex offenders. A battery of neuropsychological measures was administered to 100 participants comprising 32 FTSOs, 36 HSOs, and 32 NSOs. Both FTSOs and HSOs showed significant impairment on tests of executive function (including verbal fluency, trail-making, and the Hayling test of response inhibition) as well as on tests of verbal and verbal memory compared to NSOs; however, there was no difference between the two sex offender groups. Older adult sex offenders, overall, demonstrated poorer neuropsychological performance than older adult non-sex offenders did, although there was no difference between older first-time and historical offenders. Cognitive deficits may increase the risk of sexual offending due to impaired capacity in self-regulation, planning, judgment, and inhibition. A proportion of older adult sex offenders may be harboring acquired frontal lobe pathology.

Differences in energy expenditures and growth dilution explain higher PCB concentrations in male summer flounder

USGS Publications Warehouse

Madenjian, Charles P.; Jensen, Olaf P.; Rediske, Richard R.; O'Keefe, James P.; Vastano, Anthony R.; Pothoven, Steven A.

2016-01-01

Comparison of polychlorinated biphenyl (PCB) concentrations between the sexes of mature fish may reveal important behavioral and physiological differences between the sexes. We determined whole-fish PCB concentrations in 23 female summer flounder Paralichthys dentatus and 27 male summer flounder from New Jersey coastal waters. To investigate the potential for differences in diet or habitat utilization between the sexes, carbon and nitrogen stable isotope ratios were also determined. In 5 of the 23 female summer flounder, PCB concentrations in the somatic tissue and ovaries were determined. In addition, we used bioenergetics modeling to assess the contribution of the growth dilution effect to the observed difference in PCB concentrations between the sexes. Whole-fish PCB concentrations for females and males averaged 87 and 124 ng/g, respectively; thus males were 43% higher in PCB concentration compared with females. Carbon and nitrogen stable isotope ratios did not significantly differ between the sexes, suggesting that diet composition and habitat utilization did not vary between the sexes. Based on PCB determinations in the somatic tissue and ovaries, we predicted that PCB concentration of females would increase by 0.6%, on average, immediately after spawning due to release of eggs. Thus, the change in PCB concentration due to release of eggs did not explain the higher PCB concentrations observed in males. Bioenergetics modeling results indicated that the growth dilution effect could account for males being 19% higher in PCB concentration compared with females. Thus, the bulk of the observed difference in PCB concentrations between the sexes was not explained by growth dilution. We concluded that a higher rate of energy expenditure in males, stemming from greater activity and a greater resting metabolic rate, was most likely the primary driver for the observed difference in PCB concentrations between the sexes.

Differences in Energy Expenditures and Growth Dilution Explain Higher PCB Concentrations in Male Summer Flounder.

PubMed

Madenjian, Charles P; Jensen, Olaf P; Rediske, Richard R; O'Keefe, James P; Vastano, Anthony R; Pothoven, Steven A

2016-01-01

Comparison of polychlorinated biphenyl (PCB) concentrations between the sexes of mature fish may reveal important behavioral and physiological differences between the sexes. We determined whole-fish PCB concentrations in 23 female summer flounder Paralichthys dentatus and 27 male summer flounder from New Jersey coastal waters. To investigate the potential for differences in diet or habitat utilization between the sexes, carbon and nitrogen stable isotope ratios were also determined. In 5 of the 23 female summer flounder, PCB concentrations in the somatic tissue and ovaries were determined. In addition, we used bioenergetics modeling to assess the contribution of the growth dilution effect to the observed difference in PCB concentrations between the sexes. Whole-fish PCB concentrations for females and males averaged 87 and 124 ng/g, respectively; thus males were 43% higher in PCB concentration compared with females. Carbon and nitrogen stable isotope ratios did not significantly differ between the sexes, suggesting that diet composition and habitat utilization did not vary between the sexes. Based on PCB determinations in the somatic tissue and ovaries, we predicted that PCB concentration of females would increase by 0.6%, on average, immediately after spawning due to release of eggs. Thus, the change in PCB concentration due to release of eggs did not explain the higher PCB concentrations observed in males. Bioenergetics modeling results indicated that the growth dilution effect could account for males being 19% higher in PCB concentration compared with females. Thus, the bulk of the observed difference in PCB concentrations between the sexes was not explained by growth dilution. We concluded that a higher rate of energy expenditure in males, stemming from greater activity and a greater resting metabolic rate, was most likely the primary driver for the observed difference in PCB concentrations between the sexes.

Epigenetics and Sex Differences in the Brain: A Genome-Wide Comparison of Histone-3 Lysine-4 Trimethylation (H3K4me3) in Male and Female Mice

PubMed Central

Shen, Erica Y.; Ahern, Todd H.; Cheung, Iris; Straubhaar, Juerg; Dincer, Aslihan; Houston, Isaac; de Vries, Geert J.; Akbarian, Schahram; Forger, Nancy G.

2014-01-01

Many neurological and psychiatric disorders exhibit gender disparities, and sex differences in the brain likely explain some of these effects. Recent work in rodents points to a role for epigenetics in the development or maintenance of neural sex differences, although genome-wide studies have so far been lacking. Here we review the existing literature on epigenetics and brain sexual differentiation and present preliminary analyses on the genome-wide distribution of histone-3 lysine-4 trimethylation in a sexually dimorphic brain region in male and female mice. H3K4me3 is a histone mark primarily organized as ‘peaks’ surrounding the transcription start site of active genes. We microdissected the bed nucleus of the stria terminalis and preoptic area (BNST/POA) in adult male and female mice and used ChIP-Seq to compare the distribution of H3K4me3 throughout the genome. We found 248 genes and loci with a significant sex difference in H3K4me3. Of these, the majority (71%) had larger H3K4me3 peaks in females. Comparisons with existing databases indicate that genes and loci with increased H3K4me3 in females are associated with synaptic function and with expression atlases from related brain areas. Based on RT-PCR, only a minority of genes with a sex difference in H3K4me3 has detectable sex differences in expression at baseline conditions. Together with previous findings, our data suggest there may be sex biases in the use of epigenetic marks. Such biases could underlie sex differences in vulnerabilities to drugs or diseases that disrupt specific epigenetic processes. PMID:25131640

Sex differences in animal models of psychiatric disorders

PubMed Central

Kokras, N; Dalla, C

2014-01-01

Psychiatric disorders are characterized by sex differences in their prevalence, symptomatology and treatment response. Animal models have been widely employed for the investigation of the neurobiology of such disorders and the discovery of new treatments. However, mostly male animals have been used in preclinical pharmacological studies. In this review, we highlight the need for the inclusion of both male and female animals in experimental studies aiming at gender-oriented prevention, diagnosis and treatment of psychiatric disorders. We present behavioural findings on sex differences from animal models of depression, anxiety, post-traumatic stress disorder, substance-related disorders, obsessive–compulsive disorder, schizophrenia, bipolar disorder and autism. Moreover, when available, we include studies conducted across different stages of the oestrous cycle. By inspection of the relevant literature, it is obvious that robust sex differences exist in models of all psychiatric disorders. However, many times results are conflicting, and no clear conclusion regarding the direction of sex differences and the effect of the oestrous cycle is drawn. Moreover, there is a lack of considerable amount of studies using psychiatric drugs in both male and female animals, in order to evaluate the differential response between the two sexes. Notably, while in most cases animal models successfully mimic drug response in both sexes, test parameters and treatment-sensitive behavioural indices are not always the same for male and female rodents. Thus, there is an increasing need to validate animal models for both sexes and use standard procedures across different laboratories. Linked Articles This article is part of a themed section on Animal Models in Psychiatry Research. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2014.171.issue-20 PMID:24697577

Differences in Energy Expenditures and Growth Dilution Explain Higher PCB Concentrations in Male Summer Flounder

PubMed Central

Madenjian, Charles P.; Jensen, Olaf P.; Rediske, Richard R.; O’Keefe, James P.; Vastano, Anthony R.; Pothoven, Steven A.

2016-01-01

Comparison of polychlorinated biphenyl (PCB) concentrations between the sexes of mature fish may reveal important behavioral and physiological differences between the sexes. We determined whole-fish PCB concentrations in 23 female summer flounder Paralichthys dentatus and 27 male summer flounder from New Jersey coastal waters. To investigate the potential for differences in diet or habitat utilization between the sexes, carbon and nitrogen stable isotope ratios were also determined. In 5 of the 23 female summer flounder, PCB concentrations in the somatic tissue and ovaries were determined. In addition, we used bioenergetics modeling to assess the contribution of the growth dilution effect to the observed difference in PCB concentrations between the sexes. Whole-fish PCB concentrations for females and males averaged 87 and 124 ng/g, respectively; thus males were 43% higher in PCB concentration compared with females. Carbon and nitrogen stable isotope ratios did not significantly differ between the sexes, suggesting that diet composition and habitat utilization did not vary between the sexes. Based on PCB determinations in the somatic tissue and ovaries, we predicted that PCB concentration of females would increase by 0.6%, on average, immediately after spawning due to release of eggs. Thus, the change in PCB concentration due to release of eggs did not explain the higher PCB concentrations observed in males. Bioenergetics modeling results indicated that the growth dilution effect could account for males being 19% higher in PCB concentration compared with females. Thus, the bulk of the observed difference in PCB concentrations between the sexes was not explained by growth dilution. We concluded that a higher rate of energy expenditure in males, stemming from greater activity and a greater resting metabolic rate, was most likely the primary driver for the observed difference in PCB concentrations between the sexes. PMID:26794728

Cardiovascular mortality sex differentials in selected East Asian and Western populations.

PubMed

Zhao, Jiaying; Booth, Heather; Dear, Keith; Tu, Edward Jow-Ching

2016-10-01

Explaining patterns in the sex ratio (male/female) of cardiovascular disease (CVD) mortality would improve understanding of mortality transitions under modernisation. Little research has examined secular trends in this ratio across populations, taking age and cohort into account. We examine cohort effects in the ratios of CVD mortality (including ischaemic heart disease and cerebrovascular disease) among 4 East Asian populations that vary in the timing of their modernisation, and assess the effect of smoking on these patterns in comparison with Western populations. The sequential method for log-linear models is applied to analyse age, period and cohort effects for sex ratios. Age and cohort effects are fitted first, with population as offset; period effects are fitted in a second model using the fitted values from the first model as the offset. Lung cancer mortality serves as a proxy for smoking. Increases in sex ratios of CVD mortality began in earlier cohorts in Western than in East Asian populations. Once begun, increases were more rapid in East Asia. The cohort effect for the sex ratio of CVD mortality differs from that for lung cancer mortality. Trends in sex ratios of CVD mortality by cohort are similar before and after adjustment for lung cancer mortality in East Asia; the increasing trend across 1900-1945 cohorts is maintained in Western populations after adjustment. The sex ratio of CVD mortality has increased across successive cohorts living in increasingly modernised environments. There is scant evidence that this increase is attributable to changing sex-specific rates of smoking. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Review: Applications and benefits of sexed semen in dairy and beef herds.

PubMed

Holden, S A; Butler, S T

2018-06-01

The use of sexed semen in dairy and beef cattle production provides a number of benefits at both farm and industry levels. There is an increasing demand for dairy and beef products across the globe, which will necessitate a greater focus on improving production efficiency. In dairy farming, there is surplus production of unwanted male calves. Male dairy calves increase the risk of dystocia compared with heifer calves, and as an unwanted by-product of breeding with conventional semen, they have a low economic value. Incorporating sexed semen into the breeding programme can minimise the number of unwanted male dairy calves and reduce dystocia. Sexed semen can be used to generate herd replacements and additional heifers for herd expansion at a faster rate from within the herd, thereby minimising biosecurity risks associated with bringing in animals from different herds. Furthermore, the use of sexed semen can increase herd genetic gain compared with use of non-sorted semen. In dairy herds, a sustainable breeding strategy could combine usage of sexed semen to generate replacements only, and usage of beef semen on all dams that are not suitable for generating replacements. This results in increased genetic gain in dairy herd, increased value of beef output from the dairy herd, and reduced greenhouse gas emissions from beef. It is important to note, however, that even a small decrease in fertility of sexed semen relative to conventional semen can negate much of the economic benefit. A high fertility sexed semen product has the potential to accelerate herd expansion, minimise waste production, improve animal welfare and increase profitability compared with non-sorted conventional semen.

Sex differences in the associations between vagal reactivity and oppositional defiant disorder symptoms.

PubMed

Vidal-Ribas, Pablo; Pickles, Andrew; Tibu, Florin; Sharp, Helen; Hill, Jonathan

2017-09-01

Vagal reactivity to stress in children has been associated with future psychiatric outcomes. However, results have been mixed possibly because these effects are in opposite direction in boys and girls. These sex differences are relevant in the context of development of psychopathology, whereby the rates of psychiatric disorders differ by sex. In this study, we aimed to examine the association between vagal reactivity, assessed as a reduction in respiratory sinus arrhythmia (RSA) in response to a challenge, and the development of future oppositional defiant disorder (ODD) symptoms in boys and girls. In addition, we examine the specific associations with ODD symptom dimensions, named irritability and headstrong. We hypothesized that increased vagal reactivity was associated with increased ODD symptoms in girls and a reduction in ODD symptoms in boys. Participants were members of the Wirral Child Health and Development Study, a prospective epidemiological longitudinal study of 1,233 first-time mothers recruited at 20 weeks' gestation. RSA during four nonstressful and one stressful (still-face) procedures was assessed when children were aged 29 weeks in a sample stratified by adversity (n = 270). Maternal reports of ODD symptoms were collected when children were 2.5 years old (n = 253), 3.5 years old (n = 826), and 5 years old (n = 770). Structural equation modeling (SEM) was employed to test our hypotheses. There was a significant sex difference in the prediction of ODD symptoms due to the opposite directionality in which increasing vagal reactivity was associated with an increase in ODD symptoms in girls and a reduction of ODD symptoms in boys. This Sex by Vagal reactivity interaction was common for both ODD dimensions, with no sex by dimension-specific associations. Physiological reactivity to a stressful situation predicts differently ODD symptoms in boys and girls very early in life, with no difference across irritability and headstrong components. Findings are discussed in the context of the several mechanisms involved on the later development of distinct psychiatric disorders in boys and girls. © 2017 The Authors. Journal of Child Psychology and Psychiatry published by John Wiley & Sons Ltd on behalf of Association for Child and Adolescent Mental Health.

Patterns of Sex Desegregation in Managerial and Professional Specialty Fields, 1950-1980.

ERIC Educational Resources Information Center

Jolly, D. Leeann; And Others

1990-01-01

Patterns of the gender desegregation process in managerial and professional specialty fields are associated with differences in both occupational growth rates and gender salary levels. Sex desegregation is both widespread among higher-status fields and is increasing over time. (Author)

The relationship between sexual selection and sexual conflict.

PubMed

Kokko, Hanna; Jennions, Michael D

2014-07-18

Evolutionary conflicts of interest arise whenever genetically different individuals interact and their routes to fitness maximization differ. Sexual selection favors traits that increase an individual's competitiveness to acquire mates and fertilizations. Sexual conflict occurs if an individual of sex A's relative fitness would increase if it had a "tool" that could alter what an individual of sex B does (including the parental genes transferred), at a cost to B's fitness. This definition clarifies several issues: Conflict is very common and, although it extends outside traits under sexual selection, sexual selection is a ready source of sexual conflict. Sexual conflict and sexual selection should not be presented as alternative explanations for trait evolution. Conflict is closely linked to the concept of a lag load, which is context-dependent and sex-specific. This makes it possible to ask if one sex can "win." We expect higher population fitness if females win. Copyright © 2014 Cold Spring Harbor Laboratory Press; all rights reserved.

Mechanical contributors to sex differences in idiopathic knee osteoarthritis

PubMed Central

2012-01-01

The occurrence of knee osteoarthritis (OA) increases with age and is more common in women compared with men, especially after the age of 50 years. Recent work suggests that contact stress in the knee cartilage is a significant predictor of the risk for developing knee OA. Significant gaps in knowledge remain, however, as to how changes in musculoskeletal traits disturb the normal mechanical environment of the knee and contribute to sex differences in the initiation and progression of idiopathic knee OA. To illustrate this knowledge deficit, we summarize what is known about the influence of limb alignment, muscle function, and obesity on sex differences in knee OA. Observational data suggest that limb alignment can predict the development of radiographic signs of knee OA, potentially due to increased stresses and strains within the joint. However, these data do not indicate how limb alignment could contribute to sex differences in either the development or worsening of knee OA. Similarly, the strength of the knee extensor muscles is compromised in women who develop radiographic and symptomatic signs of knee OA, but the extent to which the decline in muscle function precedes the development of the disease is uncertain. Even less is known about how changes in muscle function might contribute to the worsening of knee OA. Conversely, obesity is a stronger predictor of developing knee OA symptoms in women than in men. The influence of obesity on developing knee OA symptoms is not associated with deviation in limb alignment, but BMI predicts the worsening of the symptoms only in individuals with neutral and valgus (knock-kneed) knees. It is more likely, however, that obesity modulates OA through a combination of systemic effects, particularly an increase in inflammatory cytokines, and mechanical factors within the joint. The absence of strong associations of these surrogate measures of the mechanical environment in the knee joint with sex differences in the development and progression of knee OA suggests that a more multifactorial and integrative approach in the study of this disease is needed. We identify gaps in knowledge related to mechanical influences on the sex differences in knee OA. PMID:23259740

Mechanical contributors to sex differences in idiopathic knee osteoarthritis.

PubMed

Nicolella, Daniel P; O'Connor, Mary I; Enoka, Roger M; Boyan, Barbara D; Hart, David A; Resnick, Eileen; Berkley, Karen J; Sluka, Kathleen A; Kwoh, C Kent; Tosi, Laura L; Coutts, Richard D; Havill, Lorena M; Kohrt, Wendy M

2012-12-23

The occurrence of knee osteoarthritis (OA) increases with age and is more common in women compared with men, especially after the age of 50 years. Recent work suggests that contact stress in the knee cartilage is a significant predictor of the risk for developing knee OA. Significant gaps in knowledge remain, however, as to how changes in musculoskeletal traits disturb the normal mechanical environment of the knee and contribute to sex differences in the initiation and progression of idiopathic knee OA. To illustrate this knowledge deficit, we summarize what is known about the influence of limb alignment, muscle function, and obesity on sex differences in knee OA. Observational data suggest that limb alignment can predict the development of radiographic signs of knee OA, potentially due to increased stresses and strains within the joint. However, these data do not indicate how limb alignment could contribute to sex differences in either the development or worsening of knee OA. Similarly, the strength of the knee extensor muscles is compromised in women who develop radiographic and symptomatic signs of knee OA, but the extent to which the decline in muscle function precedes the development of the disease is uncertain. Even less is known about how changes in muscle function might contribute to the worsening of knee OA. Conversely, obesity is a stronger predictor of developing knee OA symptoms in women than in men. The influence of obesity on developing knee OA symptoms is not associated with deviation in limb alignment, but BMI predicts the worsening of the symptoms only in individuals with neutral and valgus (knock-kneed) knees. It is more likely, however, that obesity modulates OA through a combination of systemic effects, particularly an increase in inflammatory cytokines, and mechanical factors within the joint. The absence of strong associations of these surrogate measures of the mechanical environment in the knee joint with sex differences in the development and progression of knee OA suggests that a more multifactorial and integrative approach in the study of this disease is needed. We identify gaps in knowledge related to mechanical influences on the sex differences in knee OA.

Antenatal fetal heart rate and "maternal intuition" as predictors of fetal sex.

PubMed

Genuis, S; Genuis, S K; Chang, W C

1996-06-01

To determine if the antenatal fetal heart rate is a reliable predictor of fetal sex, if there is any correlation between "maternal intuition" and fetal gender, and if maternal intuition favors one sex over the other. Two hundred twelve consecutive maternity patients with singleton gestations underwent a total of 2,261 antepartum visits. Fetal heart rate assessment was carried out between 14 and 41 weeks of gestation. At 32 weeks, participants were asked if they had a strong intuitive feeling regarding the fetal gender. Following birth, data on the infant were recorded, and the information was analyzed. There was no significant difference in the baseline fetal heart rate between male and female fetuses at any recorded gestational age. One hundred ten patients (51.9%) in the sample indicated a strong belief about the sex of their fetuses, with the majority (63.6%) predicting a male. The accuracy of maternal intuition, however, was not significantly different from that of random guessing. In the current era of declining family size, an increased focus on absolute reproductive choice and proliferating reproductive technological services, prenatal sex determination and sex selection will continue to provoke increasing attention. Fetal heart rate determination and maternal intuition, however, are not valid predictors of fetal gender.

Perceived sex discrimination amplifies the effect of antagonism on cigarette smoking.

PubMed

Sutin, Angelina R; English, Devin; Evans, Michele K; Zonderman, Alan B

2014-06-01

Compared to men, the decline in smoking during the past few decades has been slower for women, and smoking-related morbidity and mortality has increased substantially. Identifying sex-specific risk factors will inform more targeted intervention/prevention efforts. The purpose of this research is to examine the interactive effect of psychological (trait antagonism) and social (perceived sex discrimination) factors on current cigarette smoking and whether these effects differ by sex. Participants in the Healthy Aging in Neighborhoods of Diversity across the Life Span study (HANDLS; N = 454) and participants in the Health and Retirement Study (HRS; N = 8,155) completed measures of antagonism, perceived sex discrimination, and reported whether they smoked currently. Logistic regressions were used to predict smoking from antagonism, discrimination, and their interaction. Antagonism was associated with an increased risk of smoking. For women, there was an interaction between antagonism and discrimination: among women who perceived sex discrimination, every standard deviation increase in antagonism was associated with a 2.5 increased risk of current smoking in HANDLS (odds ratio [OR] = 2.54, 95% confidence interval [CI] = 1.46-4.39) and an almost 1.5 increased risk in HRS (OR = 1.43, 95% CI = 1.18-1.73). This interaction was not significant for men in either sample. In 2 independent samples, perceived sex discrimination amplified the effect of antagonism on cigarette smoking for women but not men. A hostile disposition and a perceived hostile social environment have a synergistic effect on current cigarette smoking for women.

Relations of nutritional intake to age, sex and body mass index in Japanese elderly patients with type 2 diabetes: the Japanese Elderly Diabetes Intervention Trial.

PubMed

Yoshimura, Yukio; Kamada, Chiemi; Takahashi, Keiko; Kaimoto, Tae; Iimuro, Satoshi; Ohashi, Yasuo; Araki, Atsushi; Umegaki, Hiroyuki; Sakurai, Takashi; Ito, Hideki

2012-04-01

To determine the status of nutritional intake in elderly Japanese patients with type 2 diabetes aged 65 years or older, and to clarify relations of nutritional intake to age, sex and body mass index (BMI). Clinical parameters and nutritional intake were investigated and compared in 912 (417 men, 495 women) elderly Japanese patients with type 2 diabetes registered to the Japanese Elderly Diabetes Intervention Trial. The mean daily energy intake of patients was 1802 kcal in men and 1661 kcal in women, respectively. The energy intakes per kilogram of standard bodyweight in both sexes and the energy intakes per kilogram of present bodyweight in men increased significantly with age. The protein : fat : carbohydrate (PFC) energy ratio (%E) was 15.2:25.4:59.5 in men, and 15.7:25.8:58.6 in women, respectively. Grain, oil, alcohol and soft drink intakes were higher in men than in women. Potato, fruit and green vegetable intakes were higher in women than in men. Fruit intake showed a significant age-related increase in men. In women, there was an age-related significant decrease of meat intake. An increase of BMI correlated with a significant increase in bodyweight, waist circumference, hip circumference, waist-to-hip ratio, triglycerides and diastolic blood pressure. The mean energy intake of three BMI groups, lean (BMI < 18.5 kg/m(2)), normal (18.5 kg/m(2)

Age, growth and reproduction of Sarcocheilichthys nigripinnis from the Qingyi Stream in the Huangshan Mountains.

PubMed

Yan, Yunzhi; Xu, Yinsheng; Chu, Ling; He, Shan; Chen, Yifeng

2012-06-01

Identifying the life-history strategies of fish and their associations with the surrounding environment is the basic foundation in the conservation and sustainable utilization of fish species. We examined the age, growth, and reproduction of Sarcocheilichthys nigripinnis using 352 specimens collected monthly from May 2009 to April 2010 in the Qingyi Stream. We found the sex ratio of this study population was 0.58:1 (female: male), significantly different from expected 1:1. Females and males both comprised four age groups. The annuli on the scales were formed during February and March. No obvious between-sex difference was observed in length-weight and length-scale-radius relationships. The total length in back-calculation significantly increased with age for both sexes, but did not differ significantly at each age between the two sexes. An inflection point was observed in the growth curves given by the von Bertalanffy growth function for total weight. At this inflection point, fish were 3.95 years. Both sexes reach their 50% sex maturity at age 2, when females and males were 94.7 mm and 103.0 mm total length. The temporal pattern of the gonado-somatic index corresponded to a spawning period that occurred from April through July. The non-synchronicity of egg diameter in each mature ovary during the breeding period suggested these fish may be batch spawners. The absolute fecundity increased significantly with total length and weight, whereas no significant correlation was observed between the relative fecundity and body size.

Effects of sex chromosome aneuploidies on brain development: evidence from neuroimaging studies.

PubMed

Lenroot, Rhoshel K; Lee, Nancy Raitano; Giedd, Jay N

2009-01-01

Variation in the number of sex chromosomes is a relatively common genetic condition, affecting as many as 1/400 individuals. The sex chromosome aneuploidies (SCAs) are associated with characteristic behavioral and cognitive phenotypes, although the degree to which specific individuals are affected can fall within a wide range. Understanding the effects of different dosages of sex chromosome genes on brain development may help to understand the basis for functional differences in affected individuals. It may also be informative regarding how sex chromosomes contribute to typical sexual differentiation. Studies of 47,XXY males make up the bulk of the current literature of neuroimaging studies in individuals with supernumerary sex chromosomes, with a few small studies or case reports of the other SCAs. Findings in 47,XXY males typically include decreased gray and white matter volumes, with most pronounced effects in the frontal and temporal lobes. Functional studies have shown evidence of decreased lateralization. Although the hypogonadism typically found in 47,XXY males may contribute to the decreased brain volume, the observation that 47,XXX females also show decreased brain volume in the presence of normal pubertal maturation suggests a possible direct dosage effect of X chromosome genes. Additional X chromosomes, such as in 49,XXXXY males, are associated with more markedly decreased brain volume and increased incidence of white matter hyperintensities. The limited data regarding effects of having two Y chromosomes (47,XYY) do not find significant differences in brain volume, although there are some reports of increased head size.

Effects of Sex Chromosome Aneuploidies on Brain Development: Evidence From Neuroimaging Studies

PubMed Central

Lenroot, Rhoshel K.; Lee, Nancy Raitano; Giedd, Jay N.

2010-01-01

Variation in the number of sex chromosomes is a relatively common genetic condition, affecting as many as 1/400 individuals. The sex chromosome aneuploidies (SCAs) are associated with characteristic behavioral and cognitive phenotypes, although the degree to which specific individuals are affected can fall within a wide range. Understanding the effects of different dosages of sex chromosome genes on brain development may help to understand the basis for functional differences in affected individuals. It may also be informative regarding how sex chromosomes contribute to typical sexual differentiation. Studies of 47,XXY males make up the bulk of the current literature of neuroimaging studies in individuals with supernumerary sex chromosomes, with a few small studies or case reports of the other SCAs. Findings in 47,XXY males typically include decreased gray and white matter volumes, with most pronounced effects in the frontal and temporal lobes. Functional studies have shown evidence of decreased lateralization. Although the hypogonadism typically found in 47,XXY males may contribute to the decreased brain volume, the observation that 47,XXX females also show decreased brain volume in the presence of normal pubertal maturation suggests a possible direct dosage effect of X chromosome genes. Additional X chromosomes, such as in 49,XXXXY males, are associated with more markedly decreased brain volume and increased incidence of white matter hyperintensities. The limited data regarding effects of having two Y chromosomes (47,XYY) do not find significant differences in brain volume, although there are some reports of increased head size. PMID:20014372

Sex change and effective population size: implications for population genetic studies in marine fish.

PubMed

Coscia, I; Chopelet, J; Waples, R S; Mann, B Q; Mariani, S

2016-10-01

Large variance in reproductive success is the primary factor that reduces effective population size (Ne) in natural populations. In sequentially hermaphroditic (sex-changing) fish, the sex ratio is typically skewed and biased towards the 'first' sex, while reproductive success increases considerably after sex change. Therefore, sex-changing fish populations are theoretically expected to have lower Ne than gonochorists (separate sexes), assuming all other parameters are essentially equal. In this study, we estimate Ne from genetic data collected from two ecologically similar species living along the eastern coast of South Africa: one gonochoristic, the 'santer' sea bream Cheimerius nufar, and one protogynous (female-first) sex changer, the 'slinger' sea bream Chrysoblephus puniceus. For both species, no evidence of genetic structuring, nor significant variation in genetic diversity, was found in the study area. Estimates of contemporary Ne were significantly lower in the protogynous species, but the same pattern was not apparent over historical timescales. Overall, our results show that sequential hermaphroditism may affect Ne differently over varying time frames, and that demographic signatures inferred from genetic markers with different inheritance modes also need to be interpreted cautiously, in relation to sex-changing life histories.

Sexual Fate Reprogramming in the Steroid-Induced Bi-Directional Sex Change in the Protogynous Orange-Spotted Grouper, Epinephelus coioides.

PubMed

Wu, Guan-Chung; Tey, Wei-Guan; Li, Hau-Wen; Chang, Ching-Fong

2015-01-01

Androgen administration has been widely used for masculinization in fish. The mechanism of the sex change in sexual fate regulation is not clear. Oral administration or pellet implantation was applied. We orally applied an aromatase inhibitor (AI, to decrease estrogen levels) and 17α-methyltestosterone (MT, to increase androgen levels) to induce masculinization to clarify the mechanism of the sex change in the protogynous orange-spotted grouper. After 3 mo of AI/MT administration, male characteristics were observed in the female-to-male sex change fish. These male characteristics included increased plasma 11-ketotestosterone (11-KT), decreased estradiol (E2) levels, increased male-related gene (dmrt1, sox9, and cyp11b2) expression, and decreased female-related gene (figla, foxl2, and cyp19a1a) expression. However, the reduced male characteristics and male-to-female sex change occurred after AI/MT-termination in the AI- and MT-induced maleness. Furthermore, the MT-induced oocyte-depleted follicle cells (from MT-implantation) had increased proliferating activity, and the sexual fate in a portion of female gonadal soma cells was altered to male function during the female-to-male sex change. In contrast, the gonadal soma cells were not proliferative during the early process of the male-to-female sex change. Additionally, the male gonadal soma cells did not alter to female function during the male-to-female sex change in the AI/MT-terminated fish. After MT termination in the male-to-female sex-changed fish, the differentiated male germ cells showed increased proliferating activities together with dormancy and did not show characteristics of both sexes in the early germ cells. In conclusion, these findings indicate for the first time in a single species that the mechanism involved in the replacement of soma cells is different between the female-to-male and male-to-female sex change processes in grouper. These results also demonstrate that sexual fate determination (secondary sex determination) is regulated by endogenous sex steroid levels.

Sexual Fate Reprogramming in the Steroid-Induced Bi-Directional Sex Change in the Protogynous Orange-Spotted Grouper, Epinephelus coioides

PubMed Central

Wu, Guan-Chung; Tey, Wei-Guan; Li, Hau-Wen; Chang, Ching-Fong

2015-01-01

Androgen administration has been widely used for masculinization in fish. The mechanism of the sex change in sexual fate regulation is not clear. Oral administration or pellet implantation was applied. We orally applied an aromatase inhibitor (AI, to decrease estrogen levels) and 17α-methyltestosterone (MT, to increase androgen levels) to induce masculinization to clarify the mechanism of the sex change in the protogynous orange-spotted grouper. After 3 mo of AI/MT administration, male characteristics were observed in the female-to-male sex change fish. These male characteristics included increased plasma 11-ketotestosterone (11-KT), decreased estradiol (E2) levels, increased male-related gene (dmrt1, sox9, and cyp11b2) expression, and decreased female-related gene (figla, foxl2, and cyp19a1a) expression. However, the reduced male characteristics and male-to-female sex change occurred after AI/MT-termination in the AI- and MT-induced maleness. Furthermore, the MT-induced oocyte-depleted follicle cells (from MT-implantation) had increased proliferating activity, and the sexual fate in a portion of female gonadal soma cells was altered to male function during the female-to-male sex change. In contrast, the gonadal soma cells were not proliferative during the early process of the male-to-female sex change. Additionally, the male gonadal soma cells did not alter to female function during the male-to-female sex change in the AI/MT-terminated fish. After MT termination in the male-to-female sex-changed fish, the differentiated male germ cells showed increased proliferating activities together with dormancy and did not show characteristics of both sexes in the early germ cells. In conclusion, these findings indicate for the first time in a single species that the mechanism involved in the replacement of soma cells is different between the female-to-male and male-to-female sex change processes in grouper. These results also demonstrate that sexual fate determination (secondary sex determination) is regulated by endogenous sex steroid levels. PMID:26714271

Sex differences in the outcome of juvenile social isolation on HPA axis function in rats.

PubMed

Pisu, M G; Garau, A; Boero, G; Biggio, F; Pibiri, V; Dore, R; Locci, V; Paci, E; Porcu, P; Serra, M

2016-04-21

Women are more likely than men to suffer from anxiety disorders and major depression. These disorders share hyperresponsiveness to stress as an etiological factor. Thus, sex differences in brain arousal systems and their regulation by chronic stress may account for the increased vulnerability to these disorders in women. Social isolation is a model of early life stress that results in neurobiological alterations leading to increased anxiety-like and depressive-like behaviors. Here we investigated the sex difference in the effects of post-weaning social isolation on acute stress sensitivity and behavior in rats. In both sexes, social isolation at weaning reduced basal levels of the neuroactive steroid allopregnanolone in the brain and of corticosterone in plasma. Moreover, acute stress increased plasma corticosterone levels in both group-housed and socially isolated male and female rats; however this effect was greater in male than female rats subjected to social isolation. Intriguingly, group-housed female rats showed no change in plasma and brain levels of allopregnanolone after acute foot-shock stress. The absence of stress-induced effects on allopregnanolone synthesis might be due to the physiologically higher levels of this hormone in females vs. males. Accordingly, increasing allopregnanolone levels in male rats blunted the response to foot-shock stress in these animals. Socially isolated male, but not female, rats also display depressive-like behavior and increased hippocampal brain-derived neurotrophic factor (BDNF). The ovarian steroids could "buffer" the effect of this adverse experience in females on these parameters. Finally, the dexamethasone (DEX) suppression test indicated that the chronic stress associated with social isolation impairs feedback inhibition in both sexes in which an increase in the abundance of glucocorticoid receptors (GRs) in the hippocampus was found. Altogether, these results demonstrate that social isolation affects neuroendocrine reactivity to stress, plasticity and emotionality in a sexually dimorphic manner. Copyright © 2016 IBRO. Published by Elsevier Ltd. All rights reserved.

Females and males are highly similar in language performance and cortical activation patterns during verb generation.

PubMed

Allendorfer, Jane B; Lindsell, Christopher J; Siegel, Miriam; Banks, Christi L; Vannest, Jennifer; Holland, Scott K; Szaflarski, Jerzy P

2012-10-01

To test the existence of sex differences in cortical activation during verb generation when performance is controlled for. Twenty male and 20 female healthy adults underwent functional magnetic resonance imaging (fMRI) using a covert block-design verb generation task (BD-VGT) and its event-related version (ER-VGT) that allowed for intra-scanner recordings of overt responses. Task-specific activations were determined using the following contrasts: BD-VGT covert generation>finger-tapping; ER-VGT overt generation>repetition; ER-VGT overt>covert generation. Lateral cortical regions activated during each contrast were used for calculating language lateralization index scores. Voxelwise regressions were used to determine sex differences in activation, with and without controlling for performance. Each brain region showing male/female activation differences for ER-VGT overt generation>repetition (isolating noun-verb association) was defined as a region of interest (ROI). For each subject, the signal change in each ROI was extracted, and the association between ER-VGT activation related to noun-verb association and performance was assessed separately for each sex. Males and females performed similarly on language assessments, had similar patterns of language lateralization, and exhibited similar activation patterns for each fMRI task contrast. Regression analysis controlling for overt intra-scanner performance either abolished (BD-VGT) or reduced (ER-VGT) the observed differences in activation between sexes. The main difference between sexes occurred during ER-VGT processing of noun-verb associations, where males showed greater activation than females in the right middle/superior frontal gyrus (MFG/SFG) and the right caudate/anterior cingulate gyrus (aCG) after controlling for performance. Better verb generation performance was associated with increased right caudate/aCG activation in males and with increased right MFG/SFG activation in females. Males and females exhibit similar activation patterns during verb generation fMRI, and controlling for intra-scanner performance reduces or even abolishes sex differences in language-related activation. These results suggest that previous findings of sex differences in neuroimaging studies that did not control for task performance may reflect false positives. Copyright © 2011 Elsevier Srl. All rights reserved.

Sex-Based Differences in Multiple Sclerosis (MS): Part II: Rising Incidence of Multiple Sclerosis in Women and the Vulnerability of Men to Progression of this Disease.

PubMed

Dunn, Shannon E; Gunde, Eva; Lee, Hyunwoo

2015-01-01

It is well known that a number of autoimmune diseases including multiple sclerosis (MS) predominantly affect women and there has been much attention directed toward understanding why this is the case. Past research has revealed a number of sex differences in autoimmune responses that can account for the female bias in MS. However, much less is known about why the incidence of MS has increased exclusively in women over the past half century. The recency of this increase suggests that changing environmental or lifestyle factors are interacting with biological sex to increase MS risk predominantly in females. Indeed, a number of recent studies have identified sex-specific differences in the effect of environmental factors on MS incidence. The first part of this chapter will overview this evidence and will discuss the possible scenarios of how the environment may be interacting with autoimmune mechanisms to contribute to the preferential rise in MS incidence in women. Despite the strong female bias in MS incidence, culminating evidence from natural history studies, and imaging and pathology studies suggests that males who develop MS may exhibit a more rapid decline in disability and cognitive functioning than women. Very little is known about the biological basis of this more rapid deterioration, but some insights have been provided by studies in rodent models of demyelination/remyelination. The second part of this chapter will overview the evidence that males with relapsing-onset MS undergo a more rapid progression of disease than females and will discuss potential biological mechanisms that account for this sex difference.

Gender differences in sexual risk and sexually transmitted infections correlate with gender differences in social networks among San Francisco homeless youth.

PubMed

Valente, Annie M; Auerswald, Colette L

2013-10-01

To explore whether gender differences in sexual risk and sexually transmitted infections (STIs) among homeless youth may be explained in part by gender differences in their social networks. Our sample includes 258 youth (64% male) recruited in San Francisco from street venues and transitional programs. Participants completed an audio computer-administered self-interview survey regarding their housing status and risk behaviors and an interviewer-administered survey regarding their social networks, and were tested for STIs (chlamydia and gonorrhea). We examined relationships between sexual risk and STI rates and social network characteristics by gender. Condom use was lower in young women than in young men, whereas young women were more likely to have an injection drug user (IDU) sex partner and to be diagnosed with an STI. Homeless young men were more likely to have stably housed contacts and same-sex friendships in their social networks than were young women. Stably housed network contacts were associated with increased condom use and decreased STI prevalence in young men. Same-sex friends were associated with increased condom use in young women. No young woman with a family member in her network had an IDU sex partner. Having a network member who had been recently incarcerated was associated with having an IDU sex partner for young women. Homeless young women's networks may place them at greater risk for STIs than young men. Increasing mainstream contacts and same-gender friendships may protect all homeless youth from STIs. Interventions addressing homeless young women's social networks may decrease their gender-disparate STI risk. Copyright © 2013 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Increased and mistimed sex hormone production in night shift workers.

PubMed

Papantoniou, Kyriaki; Pozo, Oscar J; Espinosa, Ana; Marcos, Josep; Castaño-Vinyals, Gemma; Basagaña, Xavier; Juanola Pagès, Elena; Mirabent, Joan; Martín, Jordi; Such Faro, Patricia; Gascó Aparici, Amparo; Middleton, Benita; Skene, Debra J; Kogevinas, Manolis

2015-05-01

Night shift work has been associated with an increased risk for breast and prostate cancer. The effect of circadian disruption on sex steroid production is a possible underlying mechanism, underinvestigated in humans. We have assessed daily rhythms of sex hormones and melatonin in night and day shift workers of both sexes. We recruited 75 night and 42 day workers, ages 22 to 64 years, in different working settings. Participants collected urine samples from all voids over 24 hours on a working day. Urinary concentrations of 16 sex steroid hormones and metabolites (estrogens, progestagens, and androgens) and 6-sulfatoxymelatonin were measured in all samples. Mean levels and peak time of total and individual metabolite production were compared between night and day workers. Night workers had higher levels of total progestagens [geometric mean ratio (GMR) 1.65; 95% confidence intervals (CI), 1.17-2.32] and androgens (GMR: 1.44; 95% CI, 1.03-2.00), compared with day workers, after adjusting for potential confounders. The increased sex hormone levels among night shift workers were not related to the observed suppression of 6-sulfatoxymelatonin. Peak time of androgens was significantly later among night workers, compared with day workers (testosterone: 12:14 hours; 10:06-14:48 vs. 08:35 hours; 06:52-10:46). We found increased levels of progestagens and androgens as well as delayed peak androgen production in night shift workers compared with day workers. The increase and mistiming of sex hormone production may explain part of the increased risk for hormone-related cancers observed in night shift workers. ©2015 American Association for Cancer Research.

Sex-Divergent Clinical Outcomes and Precision Medicine: An Important New Role for Institutional Review Boards and Research Ethics Committees.

PubMed

Segarra, Ignacio; Modamio, Pilar; Fernández, Cecilia; Mariño, Eduardo L

2017-01-01

The efforts toward individualized medicine have constantly increased in an attempt to improve treatment options. These efforts have led to the development of small molecules which target specific molecular pathways involved in cancer progression. We have reviewed preclinical studies of sunitinib that incorporate sex as a covariate to explore possible sex-based differences in pharmacokinetics and drug-drug interactions (DDI) to attempt a relationship with published clinical outputs. We observed that covariate sex is lacking in most clinical outcome reports and suggest a series of ethic-based proposals to improve research activities and identify relevant different sex outcomes. We propose a deeper integration of preclinical, clinical, and translational research addressing statistical and clinical significance jointly; to embed specific sex-divergent endpoints to evaluate possible gender differences objectively during all stages of research; to pay greater attention to sex-divergent outcomes in polypharmacy scenarios, DDI and bioequivalence studies; the clear reporting of preclinical and clinical findings regarding sex-divergent outcomes; as well as to encourage the active role of scientists and the pharmaceutical industry to foster a new scientific culture through their research programs, practice, and participation in editorial boards and Institutional Ethics Review Boards (IRBs) and Research Ethics Committees (RECs). We establish the IRB/REC as the centerpiece for the implementation of these proposals. We suggest the expansion of its competence to follow up clinical trials to ensure that sex differences are addressed and recognized; to engage in data monitoring committees to improve clinical research cooperation and ethically address those potential clinical outcome differences between male and female patients to analyze their social and clinical implications in research and healthcare policies.

Condom and Substance Use at Last Sex: Differences between MSMO and MSWO High School Youth.

PubMed

Phillips, Gregory; Kalmin, Mariah M; Turner, Blair; Felt, Dylan; Marro, Rachel; Salamanca, Paul; Beach, Lauren B

2018-05-15

HIV disproportionately impacts youth, particularly young men who have sex with men (YMSM), a population that includes subgroups of young men who have sex with men only (YMSMO) and young men who have sex with men and women (YMSMW). In 2015, among male youth, 92% of new HIV diagnoses were among YMSM. The reasons why YMSM are disproportionately at risk for HIV acquisition, however, remain incompletely explored. We performed event-level analyses to compare how the frequency of condom use, drug and/or alcohol use at last sex differed among YMSMO and YMSWO (young men who have sex with women only) over a ten-year period from 2005⁻2015 within the Youth Risk Behavior Survey (YRBS). YMSMO were less likely to use condoms at last sex compared to YMSWO. However, no substance use differences at last sexual encounter were detected. From 2005⁻2015, reported condom use at last sex significantly declined for both YMSMO and YMSWO, though the decline for YMSMO was more notable. While there were no significant differences in alcohol and substance use at last sex over the same ten-year period for YMSMO, YMSWO experienced a slight but significant decrease in reported alcohol and substance use. These event-level analyses provide evidence that YMSMO, similar to adult MSMO, may engage in riskier sexual behaviors compared to YMSWO, findings which may partially explain the increased burden of HIV in this population. Future work should investigate how different patterns of event-level HIV risk behaviors vary over time among YMSMO, YMSWO, and YMSMW, and are tied to HIV incidence among these groups.

Sex-Divergent Clinical Outcomes and Precision Medicine: An Important New Role for Institutional Review Boards and Research Ethics Committees

PubMed Central

Segarra, Ignacio; Modamio, Pilar; Fernández, Cecilia; Mariño, Eduardo L.

2017-01-01

The efforts toward individualized medicine have constantly increased in an attempt to improve treatment options. These efforts have led to the development of small molecules which target specific molecular pathways involved in cancer progression. We have reviewed preclinical studies of sunitinib that incorporate sex as a covariate to explore possible sex-based differences in pharmacokinetics and drug–drug interactions (DDI) to attempt a relationship with published clinical outputs. We observed that covariate sex is lacking in most clinical outcome reports and suggest a series of ethic-based proposals to improve research activities and identify relevant different sex outcomes. We propose a deeper integration of preclinical, clinical, and translational research addressing statistical and clinical significance jointly; to embed specific sex-divergent endpoints to evaluate possible gender differences objectively during all stages of research; to pay greater attention to sex-divergent outcomes in polypharmacy scenarios, DDI and bioequivalence studies; the clear reporting of preclinical and clinical findings regarding sex-divergent outcomes; as well as to encourage the active role of scientists and the pharmaceutical industry to foster a new scientific culture through their research programs, practice, and participation in editorial boards and Institutional Ethics Review Boards (IRBs) and Research Ethics Committees (RECs). We establish the IRB/REC as the centerpiece for the implementation of these proposals. We suggest the expansion of its competence to follow up clinical trials to ensure that sex differences are addressed and recognized; to engage in data monitoring committees to improve clinical research cooperation and ethically address those potential clinical outcome differences between male and female patients to analyze their social and clinical implications in research and healthcare policies. PMID:28785221

Early sex differences are not autism-specific: A Baby Siblings Research Consortium (BSRC) study.

PubMed

Messinger, Daniel S; Young, Gregory S; Webb, Sara Jane; Ozonoff, Sally; Bryson, Susan E; Carter, Alice; Carver, Leslie; Charman, Tony; Chawarska, Katarzyna; Curtin, Suzanne; Dobkins, Karen; Hertz-Picciotto, Irva; Hutman, Ted; Iverson, Jana M; Landa, Rebecca; Nelson, Charles A; Stone, Wendy L; Tager-Flusberg, Helen; Zwaigenbaum, Lonnie

2015-01-01

The increased male prevalence of autism spectrum disorder (ASD) may be mirrored by the early emergence of sex differences in ASD symptoms and cognitive functioning. The female protective effect hypothesis posits that ASD recurrence and symptoms will be higher among relatives of female probands. This study examined sex differences and sex of proband differences in ASD outcome and in the development of ASD symptoms and cognitive functioning among the high-risk younger siblings of ASD probands and low-risk children. Prior to 18 months of age, 1824 infants (1241 high-risk siblings, 583 low-risk) from 15 sites were recruited. Hierarchical generalized linear model (HGLM) analyses of younger sibling and proband sex differences in ASD recurrence among high-risk siblings were followed by HGLM analyses of sex differences and group differences (high-risk ASD, high-risk non-ASD, and low-risk) on the Mullen Scales of Early Learning (MSEL) subscales (Expressive and Receptive Language, Fine Motor, and Visual Reception) at 18, 24, and 36 months and Autism Diagnostic Observation Schedule (ADOS) domain scores (social affect (SA) and restricted and repetitive behaviors (RRB)) at 24 and 36 months. Of 1241 high-risk siblings, 252 had ASD outcomes. Male recurrence was 26.7 % and female recurrence 10.3 %, with a 3.18 odds ratio. The HR-ASD group had lower MSEL subscale scores and higher RRB and SA scores than the HR non-ASD group, which had lower MSEL subscale scores and higher RRB scores than the LR group. Regardless of group, males obtained lower MSEL subscale scores, and higher ADOS RRB scores, than females. There were, however, no significant interactions between sex and group on either the MSEL or ADOS. Proband sex did not affect ASD outcome, MSEL subscale, or ADOS domain scores. A 3.2:1 male:female odds ratio emerged among a large sample of prospectively followed high-risk siblings. Sex differences in cognitive performance and repetitive behaviors were apparent not only in high-risk children with ASD, but also in high-risk children without ASD and in low-risk children. Sex differences in young children with ASD do not appear to be ASD-specific but instead reflect typically occurring sex differences seen in children without ASD. Results did not support a female protective effect hypothesis.

Ecological, morphological, and histological studies on Blaps polycresta (Coleoptera: Tenebrionidae) as biomonitors of cadmium soil pollution.

PubMed

Osman, Wafaa; El-Samad, Lamia M; Mokhamer, El-Hassan; El-Touhamy, Aya; Shonouda, Mourad

2015-09-01

Soil pollution in Egypt became far more serious than before due to either the heavy usage of different toxic pesticides or aerosol deposition of industrial pollutants. The present mentioned ground beetle, Blaps polycresta Tschinkel 1975 (Coleoptera: Tenebrionidae), showed ecological, morphological, and histological alterations in adult insects as biomonitors. Two cultivated sites (reference and polluted) were chosen for sampling the insects. The results indicated a significant increase in soil cadmium concentration of the polluted site leading to sex-specific difference in cadmium accumulation in gonads and alimentary canal of insects that being higher in males than females. The cadmium pollution leads significantly to a decrease in population density, a reduction in body weight, an increase in mortality rate, and an increase in sex ratio of the insects. The results also revealed a striking decrease in body length of the polluted insects with a marked increase in the percentage of deformed gonads and alimentary canal of both sexes. Some histopathological alterations were also recorded in testis, ovary, and midgut of the polluted insects. Our results confirmed that beetles are a good bioindicator for soil pollution, and the different studied parameters could be easily employed as sensitive monitors for cadmium soil pollution.

COHORT EFFECTS OF SUICIDE MORTALITY ARE SEX SPECIFIC IN THE RAPIDLY DEVELOPED HONG KONG CHINESE POPULATION, 1976-2010.

PubMed

Chung, Roger Y; Yip, Benjamin H K; Chan, Sandra S M; Wong, Samuel Y S

2016-06-01

To examine temporal variations of age, period, and cohort on suicide mortality rate in Hong Kong (HK) from 1976 to 2010, and speculate the macroenvironmental mechanisms of the observed trends. Poisson age-period-cohort modeling was used to delineate the effects of age, period, and cohort on suicide mortality. Analysis by sex was also conducted to examine if gender difference exists for suicidal behaviours. Age-cohort model provides the best fit to the mortality data, implying that the cohort effect is likely to explain more of the contributions to HK's suicide mortality pattern than the period effect. Risk of suicide mortality increases nonlinearly with age and accelerates after age 65-69 for both sexes. Moreover, the cohort effects differ between the sexes-risk of mortality increases continually for men born after 1961, but no change is observed for women since the 1941 cohort. With increased risk of suicide mortality in younger cohorts and the age effect of suicide mortality, we may see future increase in suicide mortality as these younger cohorts age. Further studies are needed to clarify plausible associations between broader sociohistorical changes in the population impacting psychological risk factors and suicidal behaviour to better inform suicide prevention strategies. © 2015 Wiley Periodicals, Inc.

Sex differences in the neurobiology of drug addiction.

PubMed

Bobzean, Samara A M; DeNobrega, Aliza K; Perrotti, Linda I

2014-09-01

Epidemiological data demonstrate that while women report lower rates of drug use than men, the number of current drug users and abusers who are women continues to increase. In addition women progress through the phases of addiction differently than men; women transition from casual drug use to addiction faster, are more reactive to stimuli that trigger relapse, and have higher rates of relapse then men. Sex differences in physiological and psychological responses to drugs of abuse are well documented and it is well established that estrogen effects on dopamine (DA) systems are largely responsible for these sex differences. However, the downstream mechanisms that result from interactions between estrogen and the effects of drugs of abuse on the DA system are just beginning to be explored. Here we review the basic neurocircuitry which underlies reward and addiction; highlighting the neuroadaptive changes that occur in the mesolimbic dopamine reward and anti-reward/stress pathways. We propose that sex differences in addiction are due to sex differences in the neural systems which mediate positive and negative reinforcement and that these differences are modulated by ovarian hormones. This forms a neurobehavioral basis for the search for the molecular and cellular underpinnings that uniquely guide motivational behaviors and make women more vulnerable to developing and sustaining addiction than men. Copyright © 2014 Elsevier Inc. All rights reserved.

A meta-analysis of sex and race differences in perceived workplace mistreatment.

PubMed

McCord, Mallory A; Joseph, Dana L; Dhanani, Lindsay Y; Beus, Jeremy M

2018-02-01

Despite the growing number of meta-analyses published on the subject of workplace mistreatment and the expectation that women and racial minorities are mistreated more frequently than men and Whites, the degree of subgroup differences in perceived workplace mistreatment is unknown. To address this gap in the literature, we meta-analyzed the magnitude of sex and race differences in perceptions of workplace mistreatment (e.g., harassment, discrimination, bullying, incivility). Results indicate that women perceive more sex-based mistreatment (i.e., mistreatment that explicitly targets a person's sex) in the workplace than men (δ = .46; k = 43), whereas women and men report comparable perceptions of all other forms of mistreatment (δ = .02; k = 300). Similarly, although racial minorities perceive more race-based mistreatment (i.e., mistreatment that explicitly targets a person's race) in the workplace than Whites (δ = .71; k = 18), results indicate smaller race differences in all other forms of workplace mistreatment (δ = .10; k = 61). Results also indicate that sex and race differences have mostly decreased over time, although for some forms of mistreatment, subgroup differences have increased over time. We conclude by offering explanations for the observed subgroup differences in workplace mistreatment and outline directions for future research. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

The Evolution of Sex Chromosomes and Dosage Compensation in Plants.

PubMed

Muyle, Aline; Shearn, Rylan; Marais, Gabriel Ab

2017-03-01

Plant sex chromosomes can be vastly different from those of the few historical animal model organisms from which most of our understanding of sex chromosome evolution is derived. Recently, we have seen several advancements from studies on green algae, brown algae, and land plants that are providing a broader understanding of the variable ways in which sex chromosomes can evolve in distant eukaryotic groups. Plant sex-determining genes are being identified and, as expected, are completely different from those in animals. Species with varying levels of differentiation between the X and Y have been found in plants, and these are hypothesized to be representing different stages of sex chromosome evolution. However, we are also finding that sex chromosomes can remain morphologically unchanged over extended periods of time. Where degeneration of the Y occurs, it appears to proceed similarly in plants and animals. Dosage compensation (a phenomenon that compensates for the consequent loss of expression from the Y) has now been documented in a plant system, its mechanism, however, remains unknown. Research has also begun on the role of sex chromosomes in sexual conflict resolution, and it appears that sex-biased genes evolve similarly in plants and animals, although the functions of these genes remain poorly studied. Because the difficulty in obtaining sex chromosome sequences is increasingly being overcome by methodological developments, there is great potential for further discovery within the field of plant sex chromosome evolution. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Sex education and adolescent sexual behavior: do community characteristics matter?

PubMed

Kraft, Joan Marie; Kulkarni, Aniket; Hsia, Jason; Jamieson, Denise J; Warner, Lee

2012-09-01

Studies point to variation in the effects of formal sex education on sexual behavior and contraceptive use by individual and community characteristics. Using the 2002 National Survey of Family Growth, we explored associations between receipt of sex education and intercourse by age 15, intercourse by the time of the interview and use of effective contraception at first sex among 15-19-year-olds, stratified by quartiles of three community characteristics and adjusted for demographics. Across all quartiles of community characteristics, sex education reduced the odds of having sex by age 15. Sex education resulted in reduced odds of having sex by the date of the interview and increased odds of using contraception in the middle quartiles of community characteristics. Variation in the effects of sex education should be explored. Research might focus on programmatic differences by community type and programmatic needs in various types of communities. Published by Elsevier Inc.

A varied pattern of change of the sex differential in survival in the G7 countries.

PubMed

Trovato, Frank; Heyen, Nils B

2006-05-01

Over the course of the 20th century the sex differential in life expectancy at birth in the industrialized countries has widened considerably in favour of women. Starting in the early 1970s, the beginning of a reversal in the long-term pattern of this differential has been noted in some high-income countries. This study documents a sustained pattern of narrowing of this measure into the later part of the 1990s for six of the populations that comprise the G7 countries: Canada, France, Germany, Italy, England and Wales (as representative of the United Kingdom) and USA. For Japan, a persistence of widening sex differences in survival is noted. The sex differences in life expectancy are decomposed over roughly three decades (early 1970s to late 1990s) from the point of view of four major cause-of-death categories: circulatory diseases, cancers, accidents/violence/suicide, and 'other' (residual) causes. In the six countries where the sex gap has narrowed, this has resulted primarily from reduced sex differences in circulatory disease mortality, and secondarily from reduced differences in male and female death rates due to accidents, violence and suicide combined. In some of the countries sex differentials in cancer mortality have been converging lately, and this has also contributed to a narrowing of the difference in life expectancy. In Japan, males have been less successful in reducing their survival disadvantage in relation to Japanese women with regard to circulatory disease and cancer; and in the case of accidents/violence/suicide, male death rates increased during the 1990s. These trends explain the divergent pattern of the sex difference in life expectation in Japan as compared with the other G7 nations.

Effects of vitamin D supplementation during weight loss on sex hormones in postmenopausal women.

PubMed

Mason, Caitlin; De Dieu Tapsoba, Jean; Duggan, Catherine; Imayama, Ikuyo; Wang, Ching-Yun; Korde, Larissa A; Stanczyk, Frank; McTiernan, Anne

2016-06-01

The aim of the study was to compare the effects of vitamin D3 supplementation versus placebo on serum sex hormones in postmenopausal women completing a 12-month diet + exercise weight loss program. Two hundred eighteen overweight or obese women (50-75 y) with serum 25-hydroxyvitamin D at least 10 to less than 32 ng/mL ("insufficient") were randomized to either weight loss + 2,000 IU/day oral vitamin D3, or to weight loss + daily placebo. Serum sex hormone-binding globulin, estrone, total, free, and bioavailable estradiol, and testosterone were measured by radioimmunoassay before randomization and at 12 months. Mean changes were compared between groups (intent-to-treat) using generalized estimating equations. The 12-month changes in sex hormone-binding globulin, estrone, total, free, and bioavailable estradiol, and testosterone did not differ between groups (all P > 0.05). However, a greater increase in serum 25-hydroxyvitamin D was associated with a greater increase in sex hormone-binding globulin (Ptrend = 0.01), and larger decreases in free and bioavailable estradiol (Ptrend = 0.04, Ptrend = 0.03, respectively). In post-hoc analyses, we compared women randomized to vitamin D whose serum 25-hydroxyvitamin D remained insufficient (n = 38), to women who became replete (25-hydroxyvitamin D ≥32 ng/mL; n = 53). Replete women showed greater reductions in bioavailable estradiol (-1.8 vs -0.7 pg/mL), free testosterone (-0.8 vs -0.3 pg/mL), and bioavailable testosterone (-1.8 vs -0.6 ng/dL), and a greater increase in sex hormone-binding globulin (10.6 vs 4.7 nmol/L) (all P < 0.05), even after adjusting for differences in total 12-month weight loss. Overall, 12-month changes in sex hormone did not differ between groups. However, vitamin D repletion was associated with greater reductions in sex hormones during weight loss, with a possible dose-dependent effect. Future studies should test higher doses and target circulating 25-hydroxyvitamin D levels when measuring such effects.

Computer-assisted sperm morphometry fluorescence-based analysis has potential to determine progeny sex.

PubMed

Santolaria, Pilar; Pauciullo, Alfredo; Silvestre, Miguel A; Vicente-Fiel, Sandra; Villanova, Leyre; Pinton, Alain; Viruel, Juan; Sales, Ester; Yániz, Jesús L

2016-01-01

This study was designed to determine the ability of computer-assisted sperm morphometry analysis (CASA-Morph) with fluorescence to discriminate between spermatozoa carrying different sex chromosomes from the nuclear morphometrics generated and different statistical procedures in the bovine species. The study was divided into two experiments. The first was to study the morphometric differences between X- and Y-chromosome-bearing spermatozoa (SX and SY, respectively). Spermatozoa from eight bulls were processed to assess simultaneously the sex chromosome by FISH and sperm morphometry by fluorescence-based CASA-Morph. SX cells were larger than SY cells on average (P < 0.001) although with important differences between bulls. A simultaneous evaluation of all the measured features by discriminant analysis revealed that nuclear area and average fluorescence intensity were the variables selected by stepwise discriminant function analysis as the best discriminators between SX and SY. In the second experiment, the sperm nuclear morphometric results from CASA-Morph in nonsexed (mixed SX and SY) and sexed (SX) semen samples from four bulls were compared. FISH allowed a successful classification of spermatozoa according to their sex chromosome content. X-sexed spermatozoa displayed a larger size and fluorescence intensity than nonsexed spermatozoa (P < 0.05). We conclude that the CASA-Morph fluorescence-based method has the potential to find differences between X- and Y-chromosome-bearing spermatozoa in bovine species although more studies are needed to increase the precision of sex determination by this technique.

Large sex difference in adolescents on a timed line judgment task: attentional contributors and task relationship to mathematics.

PubMed

Collaer, Marcia L; Hill, Erica M

2006-01-01

Visuospatial performance, assessed with the new, group-administered Judgment of Line Angle and Position test (JLAP-13), varied with sex and mathematical competence in a group of adolescents. The JLAP-13, a low-level perceptual task, was modeled after a neuropsychological task dependent upon functioning of the posterior region of the right hemisphere [Benton et al, 1994 Contributions to Neuropsychological Assessment: A Clinical Manual (New York: Oxford University Press)]. High-school boys (N = 52) performed better than girls (N = 62), with a large effect for sex (d = 1.11). Performance increased with mathematical competence, but the sex difference did not vary significantly across different levels of mathematics coursework. On the basis of earlier work, it was predicted that male, but not female, performance in line judgment would decline with disruptions to task geometry (page frame), and that the sex difference would disappear with disruptions to geometry. These predictions were supported by a number of univariate and sex-specific analyses, although an omnibus repeated-measures analysis did not detect the predicted interaction, most likely owing to limitations in power. Thus, there is partial support for the notion that attentional predispositions or strategies may contribute to visuospatial sex differences, with males more likely than females to attend to, and rely upon, internal or external representations of task geometry. Additional support for this hypothesis may require development of new measures or experimental manipulations with more powerful geometrical disruptions.

Romanticism as a function of age, sex, and ethnicity.

PubMed

Regan, Pamela C; Anguiano, Carlos

2010-12-01

This study examined the association between romanticism (operationalized as mean score on the Romantic Beliefs Scale) and age, sex, and ethnicity in a large community sample (N = 436). Age was negatively correlated with romanticism scores; as age increased, romanticism scores decreased. No sex differences were found; men and women had similar, moderate scores. Although ethnicity largely was unrelated to romanticism, Asian/Pacific Islander participants were significantly more romantic than were African-American participants.

Roles of temperamental arousal and gender-segregated play in young children's social adjustment.

PubMed

Fabes, R A; Shepard, S A; Guthrie, I K; Martin, C L

1997-07-01

The hypothesis that gender differences in children's adjustment is partially influenced by differences in temperament and interactions with same-sex peers was examined. Fifty-seven predominantly White, middle-class preschoolers (29 boys and 28 girls, M age = 54.5 months) participated. Measures were taken of children's arousability, problem behaviors, and tendencies to play with same-sex peers. A semester later, children's peer status was assessed. Analyses revealed that arousability and same-sex peer play interacted to predict problem behaviors. For boys high in arousability, play with same-sex peers increased problem behaviors. In contrast, arousable girls who played with other girls were relatively unlikely to show problem behaviors. Moreover, the interaction of arousability and same-sex peer play predicted boys' (but not girls') peer status, and this relation was partially mediated by problem behaviors. The role of gender-related processes is discussed.

Amelogenin test: From forensics to quality control in clinical and biochemical genomics.

PubMed

Francès, F; Portolés, O; González, J I; Coltell, O; Verdú, F; Castelló, A; Corella, D

2007-01-01

The increasing number of samples from the biomedical genetic studies and the number of centers participating in the same involves increasing risk of mistakes in the different sample handling stages. We have evaluated the usefulness of the amelogenin test for quality control in sample identification. Amelogenin test (frequently used in forensics) was undertaken on 1224 individuals participating in a biomedical study. Concordance between referred sex in the database and amelogenin test was estimated. Additional sex-error genetic detecting systems were developed. The overall concordance rate was 99.84% (1222/1224). Two samples showed a female amelogenin test outcome, being codified as males in the database. The first, after checking sex-specific biochemical and clinical profile data was found to be due to a codification error in the database. In the second, after checking the database, no apparent error was discovered because a correct male profile was found. False negatives in amelogenin male sex determination were discarded by additional tests, and feminine sex was confirmed. A sample labeling error was revealed after a new DNA extraction. The amelogenin test is a useful quality control tool for detecting sex-identification errors in large genomic studies, and can contribute to increase its validity.

Sex allocation promotes the stable co-occurrence of competitive species

NASA Astrophysics Data System (ADS)

Kobayashi, Kazuya

2017-03-01

Biodiversity has long been a source of wonder and scientific curiosity. Theoretically, the co-occurrence of competitive species requires niche differentiation, and such differences are well known; however, the neutral theory, which assumes the equivalence of all individuals regardless of the species in a biological community, has successfully recreated observed patterns of biodiversity. In this research, the evolution of sex allocation is demonstrated to be the key to resolving why the neutral theory works well, despite the observed species differences. The sex allocation theory predicts that female-biased allocation evolves in species in declining density and that this allocation improves population growth, which should lead to an increase in density. In contrast, when the density increases, a less biased allocation evolves, which reduces the population growth rate and leads to decreased density. Thus, sex allocation provides a buffer against species differences in population growth. A model incorporating this mechanism demonstrates that hundreds of species can co-occur over 10,000 generations, even in homogeneous environments, and reproduces the observed patterns of biodiversity. This study reveals the importance of evolutionary processes within species for the sustainability of biodiversity. Integrating the entire biological process, from genes to community, will open a new era of ecology.

Gender differences in developmental programming of cardiovascular diseases

PubMed Central

Dasinger, John Henry; Alexander, Barbara T.

2016-01-01

Hypertension is a risk factor for cardiovascular disease, the leading cause of death worldwide. Although multiple factors contribute to the pathogenesis of hypertension, studies by Dr. David Barker reporting an inverse relationship between birth weight and blood pressure led to the hypothesis that slow growth during fetal life increases blood pressure and the risk for cardiovascular disease in later life. It is now recognized that growth during infancy and childhood in addition to exposure to adverse influences during fetal life contribute to the developmental programming of increased cardiovascular risk. Numerous epidemiological studies support the link between influences during early life with later cardiovascular health; experimental models provide proof of principle and indicate that numerous mechanisms contribute to the developmental origins of chronic disease. Sex impacts the severity of cardiovascular risk in experimental models of developmental insult. Yet, few studies examine the influence of sex on blood pressure and cardiovascular health in low birth weight men and women. Fewer still assess how aging impacts sex differences in programmed cardiovascular risk. Thus, the aim of this review is to highlight current data regarding sex differences in the developmental programming of blood pressure and cardiovascular disease. PMID:26814204

Sex differences in the developing brain as a source of inherent risk.

PubMed

McCarthy, Margaret M

2016-12-01

Brain development diverges in males and females in response to androgen production by the fetal testis. This sexual differentiation of the brain occurs during a sensitive window and induces enduring neuroanatomical and physiological changes that profoundly impact behavior. What we know about the contribution of sex chromosomes is still emerging, highlighting the need to integrate multiple factors into understanding sex differences, including the importance of context. The cellular mechanisms are best modeled in rodents and have provided both unifying principles and surprising specifics. Markedly distinct signaling pathways direct differentiation in specific brain regions, resulting in mosaicism of relative maleness, femaleness, and sameness through-out the brain, while canalization both exaggerates and constrains sex differences. Non-neuronal cells and inflammatory mediators are found in greater number and at higher levels in parts of male brains. This higher baseline of inflammation is speculated to increase male vulnerability to developmental neuropsychiatric disorders that are triggered by inflammation.

Two-hit model of schizophrenia induced by neonatal immune activation and peripubertal stress in rats: Study of sex differences and brain oxidative alterations.

PubMed

Monte, Aline Santos; Mello, Bruna Stefânia Ferreira; Borella, Vládia Célia Moreira; da Silva Araujo, Tatiane; da Silva, Francisco Eliclécio Rodrigues; Sousa, Francisca Cléa F de; de Oliveira, Antônio Carlos Pinheiro; Gama, Clarissa Severino; Seeman, Mary V; Vasconcelos, Silvânia Maria Mendes; Lucena, David Freitas De; Macêdo, Danielle

2017-07-28

Schizophrenia is considered to be a developmental disorder with distinctive sex differences. Aiming to simulate the vulnerability of the third trimester of human pregnancy to the developmental course of schizophrenia, an animal model was developed, using neonatal poly(I:C) as a first-hit, and peripubertal stress as a second-hit, i.e. a two-hit model. Since, to date, there have been no references to sex differences in the two-hit model, our study sought to determine sex influences on the development of behavior and brain oxidative change in adult rats submitted to neonatal exposure to poly(I:C) on postnatal days 5-7 as well as peripubertal unpredictable stress (PUS). Our results showed that adult two-hit rats present sex-specific behavioral alterations, with females showing more pronounced deficits in prepulse inhibition of the startle reflex and hyperlocomotion, while males showing more deficits in social interaction. Male and female animals exhibited similar working memory deficits. The levels of the endogenous antioxidant, reduced glutathione, were decreased in the prefrontal cortex (PFC) of both male and female animals exposed to both poly(I:C) and poly(I:C)+PUS. Only females presented decrements in GSH levels in the striatum. Nitrite levels were increased in the PFC of male and in the striatum of female poly(I:C)+PUS rats. Increased lipid peroxidation was observed in the PFC of females and in the striatum of males and females exposed to poly(I:C) and poly(I:C)+PUS. Thus, the present study presents evidence for sex differences in behavior and oxidative brain change induced by a two-hit model of schizophrenia. Copyright © 2017 Elsevier B.V. All rights reserved.

Nicotinamide Adenine Dinucleotide (NAD+) and Nicotinamide: Sex Differences in Cerebral Ischemia

PubMed Central

Siegel, Chad S.; McCullough, Louise D.

2013-01-01

Background Previous literature suggests that cell death pathways activated after cerebral ischemia differ between the sexes. While caspase-dependent mechanisms predominate in the female brain, caspase-independent cell death induced by activation of Poly (ADP-ribose) polymerase (PARP) predominates in the male brain. PARP-1 gene deletion decreases infarction volume in the male brain, but paradoxically increases damage in PARP-1 knockout females. Purpose This study examined stroke induced changes in NAD+, a key energy molecule involved in PARP-1 activation in both sexes. Methods Mice were subjected to Middle Cerebral Artery Occlusion and NAD+ levels were assessed. Caspase-3 activity and nuclear translocation was assessed 6 hours after ischemia. In additional cohorts, Nicotinamide (500mg/kg i.p.) a precursor of NAD+ or vehicle was administered and infarction volume was measured 24 hours after ischemia. Results Males have higher baseline NAD+ levels than females. Significant stroke-induced NAD+ depletion occurred in males and ovariectomized females but not in intact females. PARP-1 deletion prevented the stroke induced loss in NAD+ in males, but worsened NAD+ loss in PARP-1 deficient females. Preventing NAD+ loss with nicotinamide reduced infarct in wild-type males and PARP-1 knockout mice of both sexes, with no effect in WT females. Caspase-3 activity was significantly increased in PARP-1 knockout females compared to males and wild-type females, this was reversed with nicotinamide. Conclusions Sex differences exist in baseline and stroke-induced NAD+ levels. Nicotinamide protected males and PARP knockout mice, but had minimal effects in the wild-type female brain. This may be secondary to differences in energy metabolism between the sexes. PMID:23403179

Sex differences in predictors of longitudinal changes in carotid artery stiffness: the Multi-Ethnic Study of Atherosclerosis.

PubMed

Stern, Rebecca; Tattersall, Matthew C; Gepner, Adam D; Korcarz, Claudia E; Kaufman, Joel; Colangelo, Laura A; Liu, Kiang; Stein, James H

2015-02-01

To identify sex differences in predictors of longitudinal changes in carotid arterial stiffness in a multiethnic cohort. Carotid artery distensibility coefficient (DC) and Young's elastic modulus (YEM) were measured in 2650 Multi-Ethnic Study of Atherosclerosis participants (45-84 years old and free of cardiovascular disease) at baseline and after a mean of 9.4 years. Predictors of changes in DC and YEM for each sex were evaluated using multivariable linear regression models. The 1236 men (46.6%) were 60.0 (SD, 9.3) years: 40% were white, 22% black, 16% Chinese, and 22% Hispanic. The 1414 (53.4%) women were 59.8 (9.4) years old with a similar race distribution. Despite similar rates of change in DC and YEM, predictors of changes in distensibility markers differed by sex. In men, Chinese (P=0.002) and black (P=0.003) race/ethnicity, systolic blood pressure (P=0.012), and diabetes mellitus (P=0.05) were associated with more rapidly decreasing DC (accelerated stiffening). Starting antihypertensive medication was associated with improved DC (P=0.03); stopping antihypertensives was associated with more rapid stiffening (increased YEM, P=0.05). In women, higher education was associated with slower stiffening (DC, P=0.041; YEM, P<0.001) as was use of lipid-lowering medication (P=0.03), whereas baseline use of antihypertensive medications (YEM, P=0.01) and systolic blood pressure (DC, P=0.02; P=0.04) predicted increasing stiffening in women. Longitudinal changes in carotid artery stiffness are associated with systolic blood pressure and antihypertensive therapy in both sexes; however, race/ethnicity (in men) and level of education (in women) may have different contributions between the sexes. © 2014 American Heart Association, Inc.

Instrumentality, Expressivity, and Relational Qualities in the Same-Sex Friendships of College Women and Men

ERIC Educational Resources Information Center

Frey, Lisa L.; Beesley, Denise; Hurst, Rebecca; Saldana, Star; Licuanan, Brian

2016-01-01

Using the relational-cultural model (Jordan, Kaplan, Miller, Stiver, & Surrey, 1991), the authors hypothesized that instrumentality, expressivity, and the individual affective experience of same-sex friendships would predict increased relationship mutuality, with college women and men showing different predictive patterns. Overall, results…

Elevated Amygdala Perfusion Mediates Developmental Sex Differences in Trait Anxiety

PubMed Central

Kaczkurkin, Antonia N.; Moore, Tyler M.; Ruparel, Kosha; Ciric, Rastko; Calkins, Monica E.; Shinohara, Russell T.; Elliott, Mark A.; Hopson, Ryan; Roalf, David R.; Vandekar, Simon N.; Gennatas, Efstathios D.; Wolf, Daniel H.; Scott, J. Cobb; Pine, Daniel S.; Leibenluft, Ellen; Detre, John A.; Foa, Edna B.; Gur, Raquel E.; Gur, Ruben C.; Satterthwaite, Theodore D.

2016-01-01

Background Adolescence is a critical period for emotional maturation and is a time when clinically significant symptoms of anxiety and depression increase, particularly in females. However, few studies relate developmental differences in symptoms of anxiety and depression to brain development. Cerebral blood flow (CBF) is one brain phenotype that is known to have marked developmental sex differences. Methods We investigated whether developmental sex differences in CBF mediated sex differences in anxiety and depression symptoms by capitalizing upon a large sample of 875 youths who completed cross-sectional imaging as part of the Philadelphia Neurodevelopmental Cohort. Perfusion was quantified on a voxelwise basis using arterial spin labeled MRI at 3T. Perfusion images were related to trait and state anxiety using a general additive model with penalized splines, while controlling for gray matter density on a voxelwise basis. Clusters found to be related to anxiety were evaluated for interactions with age, sex, and puberty. Results Trait anxiety was associated with elevated perfusion in a network of regions including the amygdala, anterior insula, and fusiform cortex, even after accounting for pre-scanner state anxiety. Notably, these relationships strengthened with age and the transition through puberty. Moreover, higher trait anxiety in post-pubertal females was mediated by elevated perfusion of the left amygdala. Conclusions Taken together, these results demonstrate that differences in the evolution of cerebral perfusion during the adolescent period may be a critical element of the affective neurobiology underlying sex differences in anxiety and mood symptoms. PMID:27395327

The effects of sex, tissue type, and dietary components on stable isotope discrimination factors (Δ13C and Δ15N) in mammalian omnivores.

PubMed

Kurle, Carolyn M; Koch, Paul L; Tershy, Bernie R; Croll, Donald A

2014-01-01

We tested the effects of sex, tissue, and diet on stable isotope discrimination factors (Δ(13)C and Δ(15)N) for six tissues from rats fed four diets with varied C and N sources, but comparable protein quality and quantity. The Δ(13)C and Δ(15)N values ranged from 1.7-4.1‰ and 0.4-4.3‰, respectively. Females had higher Δ(15)N values than males because males grew larger, whereas Δ(13)C values did not differ between sexes. Differences in Δ(13)C values among tissue types increased with increasing variability in dietary carbon sources. The Δ(15)N values increased with increasing dietary δ(15)N values for all tissues except liver and serum, which have fast stable isotope turnover times, and differences in Δ(15)N values among tissue types decreased with increasing dietary animal protein. Our results demonstrate that variability in dietary sources can affect Δ(13)C values, protein source affects Δ(15)N values even when protein quality and quantity are controlled, and the isotope turnover rate of a tissue can influence the degree to which diet affects Δ(15)N values.

Sex differences amongst dependent heroin users: histories, clinical characteristics and predictors of other substance dependence

PubMed Central

Shand, Fiona L; Degenhardt, Louisa; Slade, Tim; Nelson, Elliot C

2010-01-01

Introduction and aims To examine differences in the characteristics and histories of male and female dependent heroin users, and in the clinical characteristics associated with multiple substance dependence diagnoses. Design and methods 1513 heroin dependent participants underwent an interview covering substance use and dependence, psychiatric history, child maltreatment, family background, adult violence and criminal history. Family background, demographic and clinical characteristics were analysed by sex. Ordinal regression was used to test for a relationship between number of substance dependence diagnoses and other clinical variables. Results Women were more likely to experience most forms of child maltreatment, to first use heroin with a boyfriend or partner, to experience ongoing adult violence at the hands of a partner, and to have a poorer psychiatric history than men. Males had more prevalent lifetime substance dependence diagnoses and criminal histories and were more likely to meet criteria for ASPD. Predictors of multiple substance dependence diagnoses for both sexes were mental health variables, antisocial behaviour, childhood sexual abuse, victim of adult violence, younger age at first cannabis use and overdose. As the number of dependence diagnoses increased, clinical and behavioural problems increased. Childhood emotional neglect was related to increasing dependence diagnoses for females but not males, whereas PTSD was a significant predictor for males but not females. Discussion and conclusions Mental health problems, other substance dependence, childhood and adult trauma were common in this sample, with sex differences indicating different treatment needs and possible different pathways to heroin dependence for men and women. PMID:20833480

Sex-based biology and the rational design of influenza vaccination strategies.

PubMed

Klein, Sabra L; Pekosz, Andrew

2014-07-15

Biological (ie, sex) differences as well as cultural (ie, gender) norms influence the acceptance and efficacy of vaccines for males and females. These differences are often overlooked in the design and implementation of vaccination strategies. Using seasonal and pandemic influenza vaccines, we document profound differences between the sexes in the acceptance, correlates of protection, and adverse reactions following vaccination in both young and older adults. Females develop higher antibody responses, experience more adverse reactions to influenza vaccines, and show greater vaccine efficacy than males. Despite greater vaccine efficacy in females, both young and older females are often less likely to accept influenza vaccines than their male counterparts. Identification of the biological mechanisms, including the hormones and genes, that underlie differential responses to vaccination is necessary. We propose that vaccines should be matched to an individual's biological sex, which could involve systematically tailoring diverse types of FDA-approved influenza vaccines separately for males and females. One goal for vaccines designed to protect against influenza and even other infectious diseases should be to increase the correlates of protection in males and reduce adverse reactions in females in an effort to increase acceptance and vaccine-induced protection in both sexes. © The Author 2014. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Molecular and Cellular Sex Differences at the Intersection of Stress and Arousal

PubMed Central

Valentino, Rita J.; Reyes, Beverly; Van Bockstaele, Elisabeth; Bangasser, Debra

2011-01-01

Elucidating the mechanisms underlying sex biases in the prevalence and severity of diseases can advance our understanding of their pathophysiological basis and serve as a guide for developing treatments. A well-established sex difference in psychiatry is the higher incidence of mood and anxiety disorders in females. These disorders share stress as a potential etiological contributor and hyperarousal as a core symptom, suggesting that the distinction between sexes lies at the intersection of stress and arousal systems. This review focuses on the link between the stress axis and the brain norepinephrine arousal system as a key point at which sex differences occur and are translated to differences in the expression of mood disorders. Evidence for a circuit designed to relay emotion-related information via the limbic corticotropin-releasing factor (CRF) system to the locus coeruleus (LC)–norepinephrine arousal system is reviewed. This is followed by recent novel findings of sex differences in CRF receptor signaling and trafficking that would result in an enhanced arousal response and a compromised ability to adapt to chronic stress in females. Finally, we discuss evidence for sex differences in LC dendritic structure that allow for increased receipt and processing of limbic information in females compared to males. Together these complementary sets of data suggest that in females, the LC arousal system is poised to process more limbic information and to respond to some of this information in an enhanced manner compared to males. The clinical and therapeutic considerations arising from this perspective are discussed. PMID:21712048

Sex Differences in the Relation of Body Composition to Cardiovascular Parameters and Functions in Korean Adolescents: A School-Based Study

PubMed Central

Song, Young-Hwan; Kim, Hae Soon; Park, Hae Sook; Jung, Jo Won; Kim, Nam Su; Noh, Chung Il; Hong, Young Mi

2014-01-01

Objective Obesity in adolescence is associated with increased cardiovascular risk. The patterns of obesity and body composition differ between boys and girls. It is uncertain how body composition correlates with the cardiovascular system and whether such correlations differ by sex in adolescents. Methods Body composition (fat-free mass (FFM), adipose mass, waist circumference (WC)) and cardiovascular parameters and functions were studied in 676 healthy Korean adolescents aged 12-16 years. Partial correlation and path analyses were done. Results WC correlated with stroke volume (SV) and cardiac output (CO), systolic blood pressure (SBP) and pulse pressure (PP), cardiac diastolic function (ratio of early to late filling velocity (E/A ratio)), and vascular function (pulse wave velocity (PWV)) in boys. Adipose mass was related to SV, CO, SBP, PP, left ventricular mass (LVM), and PWV in girls – and to E/A ratio in both sexes. FFM affected SV, CO, SBP, and PP in both sexes and LVM in boys. Cardiac systolic functions had no relation with any body composition variable in either sex. Conclusion In adolescence, the interdependence of the cardiovascular system and the body composition differs between sexes. Understanding of those relations is required to control adolescent obesity and prevent adult cardiovascular disease. PMID:24820977

An Insecticide Further Enhances Experience-Dependent Increased Behavioural Responses to Sex Pheromone in a Pest Insect

PubMed Central

Abrieux, Antoine; Mhamdi, Amel; Rabhi, Kaouther K.; Egon, Julie; Debernard, Stéphane; Duportets, Line; Tricoire-Leignel, Hélène; Anton, Sylvia; Gadenne, Christophe

2016-01-01

Neonicotinoid insecticides are widely used to protect plants against pest insects, and insecticide residues remaining in the environment affect both target and non-target organisms. Whereas low doses of neonicotinoids have been shown to disturb the behaviour of pollinating insects, recent studies have revealed that a low dose of the neonicotinoid clothianidin can improve behavioural and neuronal sex pheromone responses in a pest insect, the male moth Agrotis ipsilon, and thus potentially improve reproduction. As male moth behaviour depends also on its physiological state and previous experience with sensory signals, we wondered if insecticide effects would be dependent on plasticity of olfactory-guided behaviour. We investigated, using wind tunnel experiments, whether a brief pre-exposure to the sex pheromone could enhance the behavioural response to this important signal in the moth A. ipsilon at different ages (sexually immature and mature males) and after different delays (2 h and 24 h), and if the insecticide clothianidin would interfere with age effects or the potential pre-exposure-effects. Brief pre-exposure to the pheromone induced an age-independent significant increase of sex pheromone responses 24 h later, whereas sex pheromone responses did not increase significantly 2 h after exposure. However, response delays were significantly shorter compared to naïve males already two hours after exposure. Oral treatment with clothianidin increased sex pheromone responses in sexually mature males, confirming previous results, but did not influence responses in young immature males. Males treated with clothianidin after pre-exposure at day 4 responded significantly more to the sex pheromone at day 5 than males treated with clothianidin only and than males pre-exposed only, revealing an additive effect of experience and the insecticide. Plasticity of sensory systems has thus to be taken into account when investigating the effects of sublethal doses of insecticides on behaviour. PMID:27902778

No evidence for sex-specific effects of the maternal social environment on offspring development in Japanese quail (Coturnix japonica).

PubMed

Langen, Esther M A; von Engelhardt, Nikolaus; Goerlich-Jansson, Vivian C

2018-07-01

The social environment of reproducing females can cause physiological changes, with consequences for reproductive investment and offspring development. These prenatal maternal effects are often found to be sex-specific and may have evolved as adaptations, maximizing fitness of male and female offspring for their future environment. Female hormone levels during reproduction are considered a potential mechanism regulating sex allocation in vertebrates: high maternal androgens have repeatedly been linked to increased investment in sons, whereas high glucocorticoid levels are usually related to increased investment in daughters. However, results are not consistent across studies and therefore still inconclusive. In Japanese quail (Coturnix japonica), we previously found that pair-housed females had higher plasma androgen levels and tended to have higher plasma corticosterone levels than group-housed females. In the current study we investigate whether these differences in maternal social environment and physiology affect offspring sex allocation and physiology. Counter to our expectations, we find no effects of the maternal social environment on offspring sex ratio, sex-specific mortality, growth, circulating androgen or corticosterone levels. Also, maternal corticosterone or androgen levels do not correlate with offspring sex ratio or mortality. The social environment during reproduction therefore does not necessarily modify sex allocation and offspring physiology, even if it causes differences in maternal physiology. We propose that maternal effects of the social environment strongly depend upon the type of social stimuli and the timing of changes in the social environment and hormones with respect to the reproductive cycle and meiosis. Copyright © 2018 Elsevier Inc. All rights reserved.

Sex and age differences in the impact of the forced swimming test on the levels of steroid hormones.

PubMed

Martínez-Mota, Lucía; Ulloa, Rosa-Elena; Herrera-Pérez, Jaime; Chavira, Roberto; Fernández-Guasti, Alonso

2011-10-24

Compared with the adult disorder, depression in children exhibits differences in its neurobiology, particularly in the HPA axis regulation. The bases of such differences can be evaluated in animal models of depression. The objective of the present study was to determine age and sex differences of Wistar rats in the forced swimming test (FST). The influence of sex and age on corticosterone, estrogens and testosterone serum levels was also determined. Prepubertal rats showed immobility, swimming and climbing behaviors during the pre-test and test sessions. In addition, in the prepubertal animals, no sex differences were found during the pre-test and test sessions. Age comparisons indicated no differences in the female groups, however adult males exhibited more immobility and less swimming than young males, in both FST sessions. The young and female rats showed less immobility behavior and increased levels of estrogens after the FST. The present results indicate that the FST is an animal model suitable to evaluate depressive-like behaviors in prepubertal subjects and to explore behavioral changes related to neurodevelopment. Copyright © 2011 Elsevier Inc. All rights reserved.

Identifying factors related to Achilles tendon stress, strain, and stiffness before and after 6 months of growth in youth 10-14 years of age.

PubMed

Neugebauer, Jennifer M; Hawkins, David A

2012-09-21

The purposes of this study were (1) determine if youth peak Achilles tendon (AT) strain, peak AT stress, and AT stiffness, measured during an isometric plantar flexion, differed after six months (mos) of growth, and (2) determine if sex, physical activity level (Physical Activity Questionnaire (PAQ-C)), and/or growth rate (GR) were related to these properties. AT stress, strain, and stiffness were quantified in 20 boys (13.47±0.81 years) and 22 girls (11.18±0.82 years) at 2 times (0 and 6 mos). GR (change in height in 6 mos) was not significantly different between boys and girls (3.5±1.4 and 3.4±1.1cm/6 mos respectively). Peak AT strain and stiffness (mean 3.8±0.4% and 128.9±153.6N/mm, respectively) did not differ between testing sessions or sex. Peak AT stress (22.1±2.4 and 24.0±2.1MPa at 0 and 6 mos, respectively) did not differ between sex and increased significantly at 6 mos due to a significant decrease in AT cross-sectional area (40.6±1.3 and 38.1±1.6mm(2) at 0 and 6 mos, respectively) with no significant difference in peak AT force (882.3±93.9 and 900.3± 65.5N at 0 and 6 mos, respectively). Peak AT stress was significantly greater in subjects with greater PAQ-C scores (9.1% increase with 1 unit increase in PAQ-C score) and smaller in subjects with faster GRs (13.8% decrease with 1cm/6 mos increase in GR). These results indicate that of the AT mechanical properties quantified, none differed between sex, and only peak AT stress significantly differed after 6 months and was related to GR and physical activity. Copyright © 2012 Elsevier Ltd. All rights reserved.

Effects of blocking developmental cell death on sexually dimorphic calbindin cell groups in the preoptic area and bed nucleus of the stria terminalis

PubMed Central

2012-01-01

Background Calbindin-D28 has been used as a marker for the sexually dimorphic nucleus of the preoptic area (SDN-POA). Males have a distinct cluster of calbindin-immunoreactive (ir) cells in the medial preoptic area (CALB-SDN) that is reduced or absent in females. However, it is not clear whether the sex difference is due to the absolute number of calbindin-ir cells or to cell position (that is, spread), and the cellular mechanisms underlying the sex difference are not known. We examined the number of cells in the CALB-SDN and surrounding regions of C57Bl/6 mice and used mice lacking the pro-death gene, Bax, to test the hypothesis that observed sex differences are due to cell death. Methods Experiment 1 compared the number of cells in the CALB-SDN and surrounding regions in adult males, females, and females injected with estradiol benzoate on the day of birth. In experiment 2, cell number in the CALB-SDN and adjacent regions were compared in wild-type and Bax knockout mice of both sexes. In addition, calbindin-ir cells were quantified within the principal nucleus of the bed nucleus of the stria terminalis (BNSTp), a nearby region that is larger in males due to Bax-dependent cell death. Results Males had more cells in the CALB-SDN as well as in surrounding regions than did females, and estradiol treatment of females at birth masculinized both measures. Bax deletion had no effect on cell number in the CALB-SDN or surrounding regions but increased calbindin-ir cell number in the BNSTp. Conclusions The sex difference in the CALB-SDN of mice results from an estrogen-dependent difference in cell number with no evidence found for greater spread of cells in females. Blocking Bax-dependent cell death does not prevent sex differences in calbindin-ir cell number in the BNST or CALB-SDN but increases calbindin-ir cell number in the BNSTp of both sexes. PMID:22336348

Effects of blocking developmental cell death on sexually dimorphic calbindin cell groups in the preoptic area and bed nucleus of the stria terminalis.

PubMed

Gilmore, Richard F; Varnum, Megan M; Forger, Nancy G

2012-02-15

Calbindin-D28 has been used as a marker for the sexually dimorphic nucleus of the preoptic area (SDN-POA). Males have a distinct cluster of calbindin-immunoreactive (ir) cells in the medial preoptic area (CALB-SDN) that is reduced or absent in females. However, it is not clear whether the sex difference is due to the absolute number of calbindin-ir cells or to cell position (that is, spread), and the cellular mechanisms underlying the sex difference are not known. We examined the number of cells in the CALB-SDN and surrounding regions of C57Bl/6 mice and used mice lacking the pro-death gene, Bax, to test the hypothesis that observed sex differences are due to cell death. Experiment 1 compared the number of cells in the CALB-SDN and surrounding regions in adult males, females, and females injected with estradiol benzoate on the day of birth. In experiment 2, cell number in the CALB-SDN and adjacent regions were compared in wild-type and Bax knockout mice of both sexes. In addition, calbindin-ir cells were quantified within the principal nucleus of the bed nucleus of the stria terminalis (BNSTp), a nearby region that is larger in males due to Bax-dependent cell death. Males had more cells in the CALB-SDN as well as in surrounding regions than did females, and estradiol treatment of females at birth masculinized both measures. Bax deletion had no effect on cell number in the CALB-SDN or surrounding regions but increased calbindin-ir cell number in the BNSTp. The sex difference in the CALB-SDN of mice results from an estrogen-dependent difference in cell number with no evidence found for greater spread of cells in females. Blocking Bax-dependent cell death does not prevent sex differences in calbindin-ir cell number in the BNST or CALB-SDN but increases calbindin-ir cell number in the BNSTp of both sexes.

The Adoption of Smoking and Its Effect on the Mortality Gender Gap in Netherlands: A Historical Perspective

PubMed Central

Janssen, Fanny; van Poppel, Frans

2015-01-01

We examine in depth the effect of differences in the smoking adoption patterns of men and women on the mortality gender gap in Netherlands, employing a historical perspective. Using an indirect estimation technique based on observed lung cancer mortality from 1931 to 2012, we estimated lifetime smoking prevalence and smoking-attributable mortality. We decomposed the sex difference in life expectancy at birth into smoking-related and nonsmoking-related overall and cause-specific mortality. The smoking epidemic in Netherlands, which started among men born around 1850 and among women from birth cohort 1900 onwards, contributed substantially to the increasing sex difference in life expectancy at birth from 1931 (1.3 years) to 1982 (6.7 years), the subsequent decline to 3.7 years in 2012, and the high excess mortality among Dutch men born between 1895 and 1910. Smoking-related cancer mortality contributed most to the increase in the sex difference, whereas smoking-related cardiovascular disease mortality was mainly responsible for the decline from 1983 onwards. Examining nonsmoking-related (cause-specific) mortality shed new light on the mortality gender gap and revealed the important role of smoking-related cancers, the continuation of excess mortality among women aged 40–50, and a smaller role of biological factors in the sex difference than was previously estimated. PMID:26273613

Sex differences in memory estimates for pictures and words with multiple recall trials.

PubMed

Ionescu, Marcos D

2004-04-01

Undergraduate students (23 men and 23 women) provided memory performance estimates before and after each of three recall trials involving 80 stimuli (40 pictures and 40 words). No sex differences were found across trials for the total recall of items or for the recall of pictures and words separately. A significant increase in recall for pictures (not words) was found for both sexes across trials. The previous results of Ionescu were replicated on the first and second recall trials: men underestimated their performance on the pictures and women underestimated their performance on the word items. These differences in postrecall estimates were not found after the third recall trial: men and women alike underestimated their performance on both the picture and word items. The disappearance of item-specific sex differences in postrecall estimates for the third recall trial does not imply that men and women become more accurate at estimating their actual performance with multiple recall trials.

Sex differences on a computerized mental rotation task disappear with computer familiarization.

PubMed

Roberts, J E; Bell, M A

2000-12-01

The area of cognitive research that has produced the most consistent sex differences is spatial ability. Particularly, men consistently perform better on mental rotation tasks than do women. This study examined the effects of familiarization with a computer on performance of a computerized two-dimensional mental rotation task. Two groups of college students (N=44) performed the rotation task, with one group performing a color-matching task that allowed them to be familiarized with the computer prior to the rotation task. Among the participants who only performed the rotation task, the 11 men performed better than the 11 women. Among the participants who performed the computer familiarization task before the rotation task, how ever, there were no sex differences on the mental rotation task between the 10 men and 12 women. These data indicate that sex differences on this two-dimensional task may reflect familiarization with the computer, not the mental rotation component of the task. Further research with larger samples and increased range of task difficulty is encouraged.

Sex Differences in Panic-Relevant Responding to a 10% Carbon Dioxide-Enriched Air Biological Challenge

PubMed Central

Nillni, Yael I.; Berenz, Erin C.; Rohan, Kelly J.; Zvolensky, Michael J.

2011-01-01

The current study examined sex differences in psychological (i.e., self-reported anxiety, panic symptoms, and avoidance) and physiological (i.e., heart rate and skin conductance level) response to, and recovery from, a laboratory biological challenge. Participants were a community-recruited sample of 128 adults (63.3% women; Mage = 23.2 years, SD = 8.9) who underwent a 4-minute 10% CO2-enriched air biological challenge. As predicted, women reported more severe physical panic symptoms and avoidance (i.e., less willingness to participate in another challenge) and demonstrated increased heart rate as compared to men above and beyond the variance accounted for by other theoretically-relevant variables (recent panic attack history, neuroticism, and anxiety sensitivity). Additionally, women demonstrated a faster rate of recovery with respect to heart rate compared to men. These results are in line with literature documenting sex-specific differences in panic psychopathology, and results are discussed in the context of possible mechanisms underlying sex differences in panic vulnerability. PMID:22115836

Complementarity of Sex Differences in Brain and Behavior: From Laterality to Multi-Modal Neuroimaging

PubMed Central

Gur, Ruben C.; Gur, Raquel E.

2016-01-01

While overwhelmingly behavior is similar in males and females, and correspondingly the brains are similar, sex differences permeate both brain and behavioral measures and these differences have been the focus of increasing scrutiny by neuroscientists. Here we describe milestones of over three decades of research in brain and behavior. This research was necessarily bound by available methodology, and we began by indirect behavioral indicators of brain function such as handedness. We proceeded to using neuropsychological batteries and then to structural and functional neuroimaging that provided the foundations of a cognitive neuroscience based computerized neurocognitive battery. Sex differences were apparent and consistent in neurocognitive measures, with females performing better on memory and social cognition tasks and males on spatial processing and motor speed. Sex differences were also prominent on all major brain parameters, including higher rates of cerebral blood flow, higher percent of gray matter tissue and higher inter-hemispheric connectivity in females compared to higher percent of white matter and greater intra-hemispheric connectivity, as well as higher glucose metabolism in limbic regions in males. Many of these differences are present in childhood but they become more prominent with adolescence, perhaps linked to puberty. Together they indicate complementarity between the sexes that would result in higher adaptive diversity. PMID:27870413

Sex differences in gut microbiota in patients with major depressive disorder.

PubMed

Chen, Jian-Jun; Zheng, Peng; Liu, Yi-Yun; Zhong, Xiao-Gang; Wang, Hai-Yang; Guo, Yu-Jie; Xie, Peng

2018-01-01

Our previous studies found that disturbances in gut microbiota might have a causative role in the onset of major depressive disorder (MDD). The aim of this study was to investigate whether there were sex differences in gut microbiota in patients with MDD. First-episode drug-naïve MDD patients and healthy controls were included. 16S rRNA gene sequences extracted from the fecal samples of the included subjects were analyzed. Principal-coordinate analysis and partial least squares-discriminant analysis were used to assess whether there were sex-specific gut microbiota. A random forest algorithm was used to identify the differential operational taxonomic units. Linear discriminant-analysis effect size was further used to identify the dominant sex-specific phylotypes responsible for the differences between MDD patients and healthy controls. In total, 57 and 74 differential operational taxonomic units responsible for separating female and male MDD patients from their healthy counterparts were identified. Compared with their healthy counterparts, increased Actinobacteria and decreased Bacteroidetes levels were found in female and male MDD patients, respectively. The most differentially abundant bacterial taxa in female and male MDD patients belonged to phyla Actinobacteria and Bacteroidia, respectively. Meanwhile, female and male MDD patients had different dominant phylotypes. These results demonstrated that there were sex differences in gut microbiota in patients with MDD. The suitability of Actinobacteria and Bacteroidia as the sex-specific biomarkers for diagnosing MDD should be further explored.

PowerPoint presentation in learning physiology by undergraduates with different learning styles.

PubMed

Ankad, Roopa B; Shashikala, G V; Herur, Anita; Manjula, R; Chinagudi, Surekharani; Patil, Shailaja

2015-12-01

PowerPoint presentations (PPTs) have become routine in medical colleges because of their flexible and varied presentation capabilities. Research indicates that students prefer PPTs over the chalk-and-talk method, and there is a lot of debate over advantages and disadvantages of PPTs. However, there is no clear evidence that PPTs improve student learning/performance. Furthermore, there are a variety of learning styles with sex differences in classrooms. It is the responsibility of teacher/facilitator and student to be aware of learning style preferences to improve learning. The present study asked the following research question: do PPTs equally affect the learning of students with different learning styles in a mixed sex classroom? After we assessed students' predominant learning style according to the sensory modality that one most prefers to use when learning, a test was conducted before and after a PPT to assess student performance. The results were analyzed using Student's t-test and ANOVA with a Bonferroni post hoc test. A z-test showed no sex differences in preferred learning styles. There was significant increase in posttest performance compared with that of the pretest in all types of learners of both sexes. There was also a nonsignificant relationship among sex, learning style, and performance after the PPT. A PPT is equally effective for students with different learning style preferences and supports mixed sex classrooms. Copyright © 2015 The American Physiological Society.

Sex of respondent and credit attitudes as predictors of credit card use and debt payment.

PubMed

McCall, Michael; Eckrich, Donald W

2006-06-01

Researchers have suggested there may be sex differences in attitudes towards credit card possession and use. Undergraduates, 41 men and 41 women, completed a survey regarding their attitudes towards credit, credit card use, and repayment. Analysis indicated sex played a significant moderating role between number of credit cards used and the importance of paying off monthly balances. Women possessed more credit cards than men and engaged in more frequent shopping. Number of credit cards increased with paying off of monthly balances. Data are discussed in terms of the importance of managing credit card debt in an increasingly cashless society.

Using RNA-seq to determine patterns of sex-bias in gene expression in the brain of the sex-role reversed Gulf Pipefish (Syngnathus scovelli).

PubMed

Beal, Andria P; Martin, F Douglas; Hale, Matthew C

2018-02-01

Sex-bias in gene expression is a widespread mechanism for controlling the development of phenotypes that differ between males and females. Most studies on sex-bias in gene expression have focused on species that exhibit traditional sex-roles (male-male competition and female parental care). By contrast the Syngnathid fishes (sea horses, pipefish, and sea dragons) are a group of organisms where many species exhibit male brooding and sex-role reversal (female-female competition for mates and paternal parental care), and little is known about how patterns of sex-bias in gene expression vary in species with sex-role reversal. Here we utilize RNA-seq technology to investigate patterns of sex-bias in gene expression in the brain tissue of the Gulf Pipefish (Syngnathus scovelli) a species that exhibits sex-role reversal. Gene expression analysis identified 73 sex-biased genes, 26 genes upregulated in females and 47 genes upregulated in males. Gene ontology analysis found 52 terms enriched for the sex-biased genes in a wide range of pathways suggesting that multiple functions and processes differ between the sexes. We focused on two areas of interest: sex steroids/hormones and circadian rhythms, both of which exhibited sex-bias in gene expression, and are known to influence sexual development in other species. Lastly, the work presented herein contributes to a growing body of genome data available for the Syngnathids, increasing our knowledge on patterns of gene expression in these unusual fishes. Copyright © 2017 Elsevier B.V. All rights reserved.

The Odour of Sex: Sex-Related Differences in Volatile Compound Composition among Barn Swallow Eggs Carrying Embryos of Either Sex

PubMed Central

Costanzo, Alessandra; Panseri, Sara; Giorgi, Annamaria; Romano, Andrea; Caprioli, Manuela; Saino, Nicola

2016-01-01

Avian communication has been traditionally believed to be mainly mediated by visual and auditory channels. However, an increasing number of studies are disclosing the role of olfaction in the interaction of birds with their social environment and with other species, as well as in other behaviors such as nest recognition, food location and navigation. Olfaction has also been suggested to play a role in parent-offspring communication not only in the post- but also in the pre-hatching period. Volatile compounds produced during embryogenesis and passively released through the eggshell pores may indeed represent the only cue at parents’ disposal to assess offspring quality, including the sex composition of their clutch before hatching. In turn, sex identification before hatching may mediate adaptive strategies of allocation to either sex. In the present study, we analyzed odour composition of barn swallow eggs incubated in their nest in order to identify any sex-related differences in volatile compounds emitted. For the first time in any bird species, we also investigated whether odour composition is associated with relatedness. The evidence of differences in odour composition among eggs containing embryos of either sex indicates that parents have a cue to identify their brood sex composition even before hatching which can be used to modulate their behavior accordingly. Moreover, odour similarity within nests may represent the prerequisite for kin recognition in this species. PMID:27851741

The Sex Determination Gene transformer Regulates Male-Female Differences in Drosophila Body Size

PubMed Central

Rideout, Elizabeth J.; Narsaiya, Marcus S.; Grewal, Savraj S.

2015-01-01

Almost all animals show sex differences in body size. For example, in Drosophila, females are larger than males. Although Drosophila is widely used as a model to study growth, the mechanisms underlying this male-female difference in size remain unclear. Here, we describe a novel role for the sex determination gene transformer (tra) in promoting female body growth. Normally, Tra is expressed only in females. We find that loss of Tra in female larvae decreases body size, while ectopic Tra expression in males increases body size. Although we find that Tra exerts autonomous effects on cell size, we also discovered that Tra expression in the fat body augments female body size in a non cell-autonomous manner. These effects of Tra do not require its only known targets doublesex and fruitless. Instead, Tra expression in the female fat body promotes growth by stimulating the secretion of insulin-like peptides from insulin producing cells in the brain. Our data suggest a model of sex-specific growth in which body size is regulated by a previously unrecognized branch of the sex determination pathway, and identify Tra as a novel link between sex and the conserved insulin signaling pathway. PMID:26710087

The Sex Determination Gene transformer Regulates Male-Female Differences in Drosophila Body Size.

PubMed

Rideout, Elizabeth J; Narsaiya, Marcus S; Grewal, Savraj S

2015-12-01

Almost all animals show sex differences in body size. For example, in Drosophila, females are larger than males. Although Drosophila is widely used as a model to study growth, the mechanisms underlying this male-female difference in size remain unclear. Here, we describe a novel role for the sex determination gene transformer (tra) in promoting female body growth. Normally, Tra is expressed only in females. We find that loss of Tra in female larvae decreases body size, while ectopic Tra expression in males increases body size. Although we find that Tra exerts autonomous effects on cell size, we also discovered that Tra expression in the fat body augments female body size in a non cell-autonomous manner. These effects of Tra do not require its only known targets doublesex and fruitless. Instead, Tra expression in the female fat body promotes growth by stimulating the secretion of insulin-like peptides from insulin producing cells in the brain. Our data suggest a model of sex-specific growth in which body size is regulated by a previously unrecognized branch of the sex determination pathway, and identify Tra as a novel link between sex and the conserved insulin signaling pathway.

The relationship to age and cerebral vascular accidents of fibrin and fibrinolytic activity

PubMed Central

Hume, R.

1961-01-01

Three `normal' groups of people—young, middle-aged, and old—have been investigated with regard to the fibrin content and fibrinolytic activity of the blood. The fourth group consisted of middle-aged people who had previously sustained a cerebral vascular accident matched statistically for age with the middle-aged normals. It was concluded that fibrin increases with age but there is an interaction between age and sex, the female having a higher level in the young group and the male a higher level in the middle-aged group. There was no sex difference in the levels of fibrin in the old age group. Fibrinolytic activity increases with age and there is a positive correlation between fibrin and fibrinolytic activity but no age-sex interaction. Those with cerebral vascular accidents tended to have higher fibrin levels and lower fibrinolytic activity but the differences were not statistically significant. There did, however, appear to be an increase in antifibrinolytic activity in the cerebral vascular group. PMID:13716799

Sex-related responses of European aspen (Populus tremula L.) to combined stress: TiO2 nanoparticles, elevated temperature and CO2 concentration.

PubMed

Zhang, Yaodan; Virjamo, Virpi; Sobuj, Norul; Du, Wenchao; Yin, Ying; Nybakken, Line; Guo, Hongyan; Julkunen-Tiitto, Riitta

2018-06-15

The combined effects of climate change and chemical contaminants on plant performance are still not well understood. Especially, whether different sexes of dioecious plants respond differently to combined stresses is unknown. In order to study the sex-related responses of European aspen to soil nTiO 2 contamination (0, 50, 300 mg kg -1 ) under elevated temperature (+1.6 °C) and CO 2 (730 ppm), we conducted a study in greenhouses. Ti accumulated in roots exposed to nTiO 2 (1.1-3.3 and 2.7-21.1 mg kg -1 in 50 and 300 mg kg -1 treatments, respectively). Elevated CO 2 had no effects on Ti uptake, while elevated temperature increased it in the 300 mg kg -1 treatment. Males grew taller than females under ambient conditions, but females had greater height and biomass increment under elevated temperature. In all climate treatments, nTiO 2 increased leaf phenolics in females by 12-19% and 15-26% at 50 and 300 mg kg -1 , respectively. Leaf phenolics decreased under elevated temperature, but increased under elevated CO 2 in both sexes. Results suggest that females have better chemical defense against nTiO 2 than males under future climate conditions. In the longer run, this may cause changes in the competitive abilities of both sexes, which again may affect sex ratios and genetic variation in nature. Copyright © 2018 Elsevier B.V. All rights reserved.

The sexual dimorphism of obesity

PubMed Central

Palmer, Biff F.; Clegg, Deborah J.

2015-01-01

The NIH has recently highlighted the importance of sexual dimorphisms and has mandated inclusion of both sexes in clinical trials and basic research. In this review we highlight new and novel ways sex hormones influence body adiposity and the metabolic syndrome. Understanding how and why metabolic processes differ by sex will enable clinicians to target and personalize therapies based on gender. Adipose tissue function and deposition differ by sex. Females differ with respect to distribution of adipose tissues, males tend to accrue more visceral fat, leading to the classic android body shape which has been highly correlated to increased cardiovascular risk; whereas females accrue more fat in the subcutaneous depot prior to menopause, a feature which affords protection from the negative consequences associated with obesity and the metabolic syndrome. After menopause, fat deposition and accrual shift to favor the visceral depot. This shift is accompanied by a parallel increase in metabolic risk reminiscent to that seen in men. A full understanding of the physiology behind why, and by what mechanisms, adipose tissues accumulate in specific depots and how these depots differ metabolically by sex is important in efforts of prevention of obesity and chronic disease. Estrogens, directly or through activation of their receptors on adipocytes and in adipose tissues, facilitate adipose tissue deposition and function. Evidence suggests that estrogens augment the sympathetic tone differentially to the adipose tissue depots favoring lipid accumulation in the subcutaneous depot in women and visceral fat deposition in men. At the level of adipocyte function, estrogens and their receptors influence the expandability of fat cells enhancing the expandability in the subcutaneous depot and inhibiting it in the visceral depot. Sex hormones clearly influence adipose tissue function and deposition, determining how to capture and utilize their function in a time of caloric surfeit, requires more information. The key will be harnessing the beneficial effects of sex hormones in such a way as to provide ‘healthy’ adiposity. PMID:25578600

Lateralized sex differences in stress-induced dopamine release in the rat.

PubMed

Sullivan, Ron M; Dufresne, Marc M; Waldron, Jay

2009-02-18

This study examined the possibility that hemispheric differences in stress-induced brain activation vary as a function of sex. Using in-vivo voltammetry, increases in extracellular dopamine release in response to predator odour and tail pinch stress were recorded bilaterally and simultaneously in either the infralimbic cortex or basolateral amygdala. In both stress-sensitive brain regions, significant sex x hemisphere interactions were observed, with males and females showing greater dopamine activation in right-brain and left-brain structures, respectively. Cortical asymmetries in dopamine release also showed sex-specific correlations with stress-induced neuroendocrine activation. Given the intriguing human parallels, we suggest that differential cerebral lateralization may be highly relevant to the disproportionately high incidence of stress-related disorders such as depression and anxiety seen in women.

AIDS risk reduction strategies among United States and Swedish heterosexual university students.

PubMed

Weinberg, M S; Lottes, I L; Aveline, D

1998-08-01

Attitudes toward sex and condoms in the U.S. are more negative and less monolithic than in Sweden. We investigated the possible effect of this on AIDS prevention strategies by comparing women and men who were heterosexual university students in the two countries (Sweden: n = 570; U.S.: n = 407). Using self-administered questionnaires, subjects were asked about their sexual activities, safer sex practices, numbers of partners, and condom use. American students took a more multifaceted approach to safer sex--combining changes in sexual activities, reductions in casual sex, and increased condom use with both steady and nonsteady partners. Swedish students took a more singular approach--consistently using condoms with nonsteady partners. It is suggested that the difference in Swedish practices results from fundamental differences in sexual attitudes between the countries.

Hormonal regulation of β-myosin heavy chain expression in the mouse left ventricle.

PubMed

Patrizio, Mario; Musumeci, Marco; Piccone, Ambra; Raggi, Carla; Mattei, Elisabetta; Marano, Giuseppe

2013-03-01

We investigated the influence of sex hormones on the expression of α- and β-cardiac myosin heavy chain isoforms (α-MHC and β-MHC) in C57bl/6 mice of both sexes under physiological and pathological conditions. In the left ventricles (LVs) of fertile female mice, β-MHC expression was tenfold higher compared with the age-matched males, whereas no difference was found in α-MHC expression. These differences disappeared after ovariectomy or in immature mice. We also found a sex-related difference in expression of β-adrenoceptors (β1-AR), as mRNA levels of this gene were 40% lower in fertile females compared with males of the same age but did not differ in prepubertal or ovariectomized animals. Interestingly, the deletion of both β1- and β2-ARs abolished sex difference of β-MHC expression, as mRNA levels in the LVs of knockout males were increased and reached values comparable to those of knockout females. Moreover, the β1-AR antagonist metoprolol induced about a threefold increase in β-MHC expression in adult male mice. The capability of gender to regulate β-MHC expression was also evaluated in the presence of hemodynamic overload. Thoracic aortic coarctation (TAC) produced cardiac hypertrophy along with a 12-fold increase in β-MHC and a 50% decrease in β1-AR expression in males but not in females, thus abolishing the gender difference observed in sham animals for such genes. By contrast, TAC did not change β2-AR expression. In conclusion, our results show that the expression of β-MHC and β1-AR in the LVs undergo gender-related and correlated changes under both physiological and pathological conditions and suggest a role of β1-AR-mediated signaling.

Sex differences in T cells in hypertension.

PubMed

Tipton, Ashlee J; Sullivan, Jennifer C

2014-12-01

Hypertension is a major risk factor for cardiovascular disease, stroke, and end-organ damage. There is a sex difference in blood pressure (BP) that begins in adolescence and continues into adulthood, in which men have a higher prevalence of hypertension compared with women until the sixth decade of life. Less than 50% of hypertensive adults in the United States manage to control their BP to recommended levels using current therapeutic options, and women are more likely than are men to have uncontrolled high BP. This, is despite the facts that more women compared with men are aware that they have hypertension and that women are more likely to seek treatment for the disease. Novel therapeutic targets need to be identified in both sexes to increase the percentage of hypertensive individuals with controlled BP. The purpose of this article was to review the available literature on the role of T cells in BP control in both sexes, and the potential therapeutic application/implications of targeting immune cells in hypertension. A search of PubMed was conducted to determine the impact of sex on T cell-mediated control of BP. The search terms included sex, gender, estrogen, testosterone, inflammation, T cells, T regulatory cells, Th17 cells, hypertension, and blood pressure. Additional data were included from our laboratory examinations of cytokine expression in the kidneys of male and female spontaneously hypertensive rats (SHRs) and differential gene expression in both the renal cortex and mesenteric arterial bed of male and female SHRs. There is a growing scientific literature base regarding the role of T cells in the pathogenesis of hypertension and BP control; however, the majority of these studies have been performed exclusively in males, despite the fact that both men and women develop hypertension. There is increasing evidence that although T cells also mediate BP in females, there are distinct differences in both the T-cell profile and the functional impact of sex differences in T cells on cardiovascular health, although more work is needed to better define the relative impact of different T-cell subtypes on BP in both sexes. The challenge now is to fully understand the molecular mechanisms by which the immune system regulates BP and how the different components of the immune system interact so that specific mechanisms can be targeted therapeutically without compromising natural immune defenses. Copyright © 2014 Elsevier HS Journals, Inc. All rights reserved.

Influences of gender role and anxiety on sex differences in temporal summation of pain.

PubMed

Robinson, Michael E; Wise, Emily A; Gagnon, Christine; Fillingim, Roger B; Price, Donald D

2004-03-01

Previous research has consistently shown moderate to large differences between pain reports of men and women undergoing experimental pain testing. These differences have been shown for a variety of types of stimulation. However, only recently have sex differences been demonstrated for temporal summation of second pain. This study examined sex differences in response to temporal summation of second pain elicited by thermal stimulation of the skin. The relative influences of state anxiety and gender role expectations on temporal summation were investigated. Asymptomatic undergraduates (37 women and 30 men) underwent thermal testing of the thenar surface of the hand in a temporal summation protocol. Our results replicated those of Fillingim et al indicating that women showed increased temporal summation compared to men. We extended those findings to demonstrate that temporal summation is influenced by anxiety and gender role stereotypes about pain responding. When anxiety and gender role stereotypes are taken into account, sex is no longer a significant predictor of temporal summation. These findings highlight the contribution of social learning factors in the differences between sexes' pain perception. Results of this study demonstrate that psychosocial variables influence pain mechanisms. Temporal summation was related to gender role expectations of pain and anxiety. These variables explain a significant portion of the differences between men and women's pain processing, and may be related to differences in clinical presentation.

Same-Sex Behavior and Health Indicators of Sexually Experienced Filipino Young Adults.

PubMed

Cheng, Chia-Hsin Emily; Gipson, Jessica D; Perez, Tita Lorna; Cochran, Susan D

2016-08-01

The Philippines is one of seven countries in which HIV incidence has recently increased-much of this increase has been among men who have sex with men. Despite this trend, knowledge on sexuality and same-sex behaviors in the Philippines is limited. This study examines same-sex behavior, sexual outcomes, substance use, and psychological distress among young adults participating in the 2005 Cebu Longitudinal Health and Nutrition Survey (CLHNS). We use gender-stratified, multivariate models to compare young adults who reported same-sex behaviors and those who did not. Among a cohort of 1,912 Filipino young adults (ages 20-22), 58.2 % were sexually experienced and 15.1 % of them reported same-sex sexual contacts or romantic relationships. Compared to females, more males reported same-sex sexual contact (19.4 vs. 2.3 %) or same-sex romantic relationships (9.2 vs. 4.1 %). Young adults reporting same-sex behavior had higher odds of smoking, drug use, perceived stress, and more sexual partners as compared to their peers. Males who reported same-sex behavior initiated sex earlier than those males who did not report same-sex behaviors. There were no significant differences in depressive distress. Earlier sexual initiation and higher levels of substance use among Filipino young adults engaging in same-sex behavior highlight the need to address unique health issues within this population. Mixed findings for depressive distress and perceived stress indicate that further investigation is needed to explore the potential impacts of same-sex status on mental health outcomes, particularly in lower- and middle-income countries such as the Philippines.

Cigarette Smoking in Same-Sex and Different-Sex Unions: The Role of Socioeconomic and Psychological Factors

PubMed Central

Liu, Hui; Brown, Dustin

2014-01-01

Cigarette smoking has long been a target of public health intervention because it substantially contributes to morbidity and mortality. Individuals in different-sex marriages have lower smoking risk (i.e., prevalence and frequency) than different-sex cohabiters. However, little is known about the smoking risk of individuals in same-sex cohabiting unions. We compare the smoking risk of individuals in different-sex marriages, same-sex cohabiting unions, and different-sex cohabiting unions using pooled cross-sectional data from the 1997–2010 National Health Interview Surveys (N = 168,514). We further examine the role of socioeconomic status (SES) and psychological distress in the relationship between union status and smoking. Estimates from multinomial logistic regression models reveal that same-sex and different-sex cohabiters experience similar smoking risk when compared to one another, and higher smoking risk when compared to the different-sex married. Results suggest that SES and psychological distress factors cannot fully explain smoking differences between the different-sex married and same-sex and different-sex cohabiting groups. Moreover, without same-sex cohabiter’s education advantage, same-sex cohabiters would experience even greater smoking risk relative to the different-sex married. Policy recommendations to reduce smoking disparities among same-sex and different-sex cohabiters are discussed. PMID:25346559

How are social capital and sense of coherence associated with hazardous alcohol use? Findings from a large population-based Swedish sample of adults.

PubMed

Larm, Peter; Åslund, Cecilia; Starrin, Bengt; Nilsson, K W

2016-07-01

This study examined whether social capital and a sense of coherence are associated with hazardous alcohol use in a large population-based Swedish sample. In particular, the objectives were (a) to examine which of five subdimensions of social capital is associated with hazardous alcohol use, (b) to investigate the moderating role of sense of coherence and (c) to examine possible sex differences. A postal survey was distributed to a sample of respondents (aged 18-84 years) from five Swedish counties that was stratified by sex, age and city; 40,674 (59.2%) participants responded, of which 45.5% were men and 54.5% were women with a mean±SD age of 53.8±17.9 years. Structural dimensions of social capital were associated with an increased probability of hazardous alcohol use among both men and women, whereas the increased probability associated with cognitive dimensions occurred mostly among women. Sense of coherence was robustly associated with a decreased probability of hazardous alcohol use among both men and women. There were few moderating effects of sense of coherence and sex differences emerged mainly for the cognitive dimension of social capital. CONCLUSIONS ASSOCIATIONS BETWEEN SOCIAL CAPITAL DIMENSIONS AND HAZARDOUS ALCOHOL USE WERE PARTLY SEX-SPECIFIC, WHEREAS THE BENEFITS OF A SENSE OF COHERENCE ACCRUED TO BOTH SEXES SOCIAL CAPITAL DIMENSIONS AND SENSE OF COHERENCE WERE GENERALLY UNRELATED TO EACH OTHER ONLY ASSOCIATIONS BETWEEN THE COGNITIVE DIMENSIONS OF SOCIAL CAPITAL AND HAZARDOUS ALCOHOL USE DIFFERED BY SEX. © 2016 the Nordic Societies of Public Health.

Perspectives on condom breakage: a qualitative study of female sex workers in Bangalore, India.

PubMed

Gurav, Kaveri; Bradley, Janet; Chandrashekhar Gowda, G; Alary, Michel

2014-01-01

A qualitative study was conducted to obtain a detailed understanding of two key determinants of condom breakage - 'rough sex' and poor condom fit - identified in a recent telephone survey of female sex workers, in Bangalore, India. Transcripts from six focus-group discussions involving 35 female sex workers who reported condom breakage during the telephone survey were analysed. Rough sex in different forms, from over-exuberance to violence, was often described by sex workers as a result of clients' inebriation and use of sexual stimulants, which, they report, cause tumescence, excessive thrusting and sex that lasts longer than usual, thereby increasing the risk of condom breakage. Condom breakage in this setting is the result of a complex set of social situations involving client behaviours and power dynamics that has the potential to put the health and personal lives of sex workers at risk. These findings and their implications for programme development are discussed.

Sexual selection affects the evolution of lifespan and ageing in the decorated cricket Gryllodes sigillatus.

PubMed

Archer, C R; Zajitschek, F; Sakaluk, S K; Royle, N J; Hunt, J

2012-10-01

Recent work suggests that sexual selection can influence the evolution of ageing and lifespan by shaping the optimal timing and relative costliness of reproductive effort in the sexes. We used inbred lines of the decorated cricket, Gryllodes sigillatus, to estimate the genetic (co)variance between age-dependent reproductive effort, lifespan, and ageing within and between the sexes. Sexual selection theory predicts that males should die sooner and age more rapidly than females. However, a reversal of this pattern may be favored if reproductive effort increases with age in males but not in females. We found that male calling effort increased with age, whereas female fecundity decreased, and that males lived longer and aged more slowly than females. These divergent life-history strategies were underpinned by a positive genetic correlation between early-life reproductive effort and ageing rate in both sexes, although this relationship was stronger in females. Despite these sex differences in life-history schedules, age-dependent reproductive effort, lifespan, and ageing exhibited strong positive intersexual genetic correlations. This should, in theory, constrain the independent evolution of these traits in the sexes and may promote intralocus sexual conflict. Our study highlights the importance of sexual selection to the evolution of sex differences in ageing and lifespan in G. sigillatus. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

Effects of Sex and Stress on Trigeminal Neuropathic Pain-Like Behavior in Rats.

PubMed

Korczeniewska, Olga Anna; Khan, Junad; Tao, Yuanxiang; Eliav, Eli; Benoliel, Rafael

2017-01-01

To investigate the effects and interactions of sex and stress (provoked by chronic restraint [RS]) on pain-like behavior in a rat model of trigeminal neuropathic pain. The effects of sex and RS (carried out for 14 days as a model for stress) on somatosensory measures (reaction to pinprick, von Frey threshold) in a rat model of trigeminal neuropathic pain were examined. The study design was 2 × 4, with surgery (pain) and sham surgery (no pain) interacting with male restrained (RS) and unrestrained (nRS) rats and female RS and nRS rats. A total of 64 Sprague Dawley rats (32 males and 32 females) were used. Half of the animals in each sex group underwent RS, and the remaining half were left unstressed. Following the RS period, trigeminal neuropathic pain was induced by unilateral infraorbital nerve chronic constriction injury (IOCCI). Half of the animals in the RS group and half in the nRS group (both males and females) were exposed to IOCCI, and the remaining halves to sham surgery. Elevated plus maze (EPM) assessment and plasma interferon gamma (IFN-γ) levels were used to measure the effects of RS. Analysis of variance (ANOVA) was used to assess the effects of stress, sex, and their interactions on plasma IFN-γ levels, changes in body weight, EPM parameters, tactile allodynia, and mechanohyperalgesia. Pairwise comparisons were performed by using Tukey post hoc test corrected for multiple comparisons. Both male and female RS rats showed significantly altered exploratory behavior (as measured by EPM) and had significantly lower plasma IFN-γ levels than nRS rats. Rats exposed to RS gained weight significantly slower than the nRS rats, irrespective of sex. Following RS but before surgery, RS rats showed significant bilateral reductions in von Frey thresholds and significantly increased pinprick response difference scores compared to nRS rats, irrespective of sex. From 17 days postsurgery, RSIOCCI rats showed significantly reduced von Frey thresholds and significantly increased pinprick response difference scores compared to nRS-IOCCI rats, and the von Frey thresholds were significantly lower in females than in males. RS-sham females-but not RS-sham males-developed persistently reduced thresholds and increased pinprick response difference scores. RS produced an increased bilateral sensitivity to stimuli applied to the vibrissal pad following infraorbital nerve injury, irrespective of sex. This observed sensitivity subsequently persisted in RS-sham female rats but not in RS-sham male rats. Stress induced a significant but moderate increase in pain-like behavior in female rats compared to male rats. RS had no significant sex effects on IFN-γ levels, EPM parameters, or body weight gain. This suggests that stress may have a selective effect on pain-like behavior in both sexes, but the possible mechanisms are unclear.

A sea lamprey (Petromyzon marinus) sex pheromone mixture increases trap catch relative to a single synthesized component in specific environments

USGS Publications Warehouse

Johnson, Nicholas S.; Tix, John A.; Hlina, Benjamin L.; Wagner, C. Michael; Siefkes, Michael J.; Wang, Huiyong; Li, Weiming

2015-01-01

Spermiating male sea lamprey (Petromyzon marinus) release a sex pheromone, of which a component, 7α, 12α, 24-trihydoxy-3-one-5α-cholan-24-sulfate (3kPZS), has been identified and shown to induce long distance preference responses in ovulated females. However, other pheromone components exist, and when 3kPZS alone was used to control invasive sea lamprey populations in the Laurentian Great Lakes, trap catch increase was significant, but gains were generally marginal. We hypothesized that free-ranging sea lamprey populations discriminate between a partial and complete pheromone while migrating to spawning grounds and searching for mates at spawning grounds. As a means to test our hypothesis, and to test two possible uses of sex pheromones for sea lamprey control, we asked whether the full sex pheromone mixture released by males (spermiating male washings; SMW) is more effective than 3kPZS in capturing animals in traditional traps (1) en route to spawning grounds and (2) at spawning grounds. At locations where traps target sea lampreys en route to spawning grounds, SMW-baited traps captured significantly more sea lampreys than paired 3kPZS-baited traps (~10 % increase). At spawning grounds, no difference in trap catch was observed between 3kPZS and SMW-baited traps. The lack of an observed difference at spawning grounds may be attributed to increased pheromone competition and possible involvement of other sensory modalities to locate mates. Because fishes often rely on multiple and sometimes redundant sensory modalities for critical life history events, the addition of sex pheromones to traditionally used traps is not likely to work in all circumstances. In the case of the sea lamprey, sex pheromone application may increase catch when applied to specifically designed traps deployed in streams with low adult density and limited spawning habitat.

Sex and cultural differences in spatial performance between Japanese and North Americans.

PubMed

Sakamoto, Maiko; Spiers, Mary V

2014-04-01

Previous studies have suggested that Asians perform better than North Americans on spatial tasks but show smaller sex differences. In this study, we evaluated the relationship between long-term experience with a pictorial written language and spatial performance. It was hypothesized that native Japanese Kanji (a complex pictorial written language) educated adults would show smaller sex differences on spatial tasks than Japanese Americans or North Americans without Kanji education. A total of 80 young healthy participants (20 native Japanese speakers, 20 Japanese Americans-non Japanese speaking, and 40 North Americans-non Japanese speaking) completed the Rey Complex Figure Test (RCFT), the Mental Rotations Test (MRT), and customized 2D and 3D spatial object location memory tests. As predicted, main effects revealed men performed better on the MRT and RCFT and women performed better on the spatial object location memory tests. Also, as predicted, native Japanese performed better on all tests than the other groups. In contrast to the other groups, native Japanese showed a decreased magnitude of sex differences on aspects of the RCFT (immediate and delayed recall) and no significant sex difference on the efficiency of the strategy used to copy and encode the RCFT figure. This study lends support to the idea that intensive experience over time with a pictorial written language (i.e., Japanese Kanji) may contribute to increased spatial performance on some spatial tasks as well as diminish sex differences in performance on tasks that most resemble Kanji.

Sex differences in fluctuating asymmetry of body traits in chewing lice Docophorulus coarctatus (Phthiraptera: Ischnocera).

PubMed

Tryjanowski, Piotr; Adamski, Zbigniew

2007-10-01

Fluctuating asymmetry (FA) that reflects randomly directed deviations from bilateral symmetry has been shown to increase in organisms exposed to environmental and/or genetic stress. We studied fluctuating asymmetry in head and prothorax of chewing lice Docophorulus coarctatus, a parasite of the great grey shrike Lanius excubitor, to investigate associations between parasite body size and fluctuating asymmetry. Samples of ten individual lice (five females, five males) were randomly collected for measurements from 32 shrikes. Relative FA (scaled to trait size) was estimated for head and prothorax. Sex and trait differences in FA were very distinct (all differences significant at P<0.001). However, relative FA of head was not a predictor to relative FA of prothorax in either sex. Moreover, relative FA measurements of females and males from the same host were not significantly correlated, contrary to expectation if hosts imposed similar selection pressures on parasites of the two sexes. Relative FA of a trait was negatively related to its size, except for the relationship between relative FA of prothorax and prothorax in females. Differences in FA between traits may be explained by time when host condition affects louse developmental biology, with the head developing in a very short time during larval and nymph stages. The sex difference in asymmetry was probably related to different selection pressures by hosts on the sexes of the parasite, with females generally being under more intense selection.

Using lod scores to detect sex differences in male-female recombination fractions.

PubMed

Feenstra, B; Greenberg, D A; Hodge, S E

2004-01-01

Human recombination fraction (RF) can differ between males and females, but investigators do not always know which disease genes are located in genomic areas of large RF sex differences. Knowledge of RF sex differences contributes to our understanding of basic biology and can increase the power of a linkage study, improve gene localization, and provide clues to possible imprinting. One way to detect these differences is to use lod scores. In this study we focused on detecting RF sex differences and answered the following questions, in both phase-known and phase-unknown matings: (1) How large a sample size is needed to detect a RF sex difference? (2) What are "optimal" proportions of paternally vs. maternally informative matings? (3) Does ascertaining nonoptimal proportions of paternally or maternally informative matings lead to ascertainment bias? Our results were as follows: (1) We calculated expected lod scores (ELODs) under two different conditions: "unconstrained," allowing sex-specific RF parameters (theta(female), theta(male)); and "constrained," requiring theta(female) = theta(male). We then examined the DeltaELOD (identical with difference between maximized constrained and unconstrained ELODs) and calculated minimum sample sizes required to achieve statistically significant DeltaELODs. For large RF sex differences, samples as small as 10 to 20 fully informative matings can achieve statistical significance. We give general sample size guidelines for detecting RF differences in informative phase-known and phase-unknown matings. (2) We defined p as the proportion of paternally informative matings in the dataset; and the optimal proportion p(circ) as that value of p that maximizes DeltaELOD. We determined that, surprisingly, p(circ) does not necessarily equal (1/2), although it does fall between approximately 0.4 and 0.6 in most situations. (3) We showed that if p in a sample deviates from its optimal value, no bias is introduced (asymptotically) to the maximum likelihood estimates of theta(female) and theta(male), even though ELOD is reduced (see point 2). This fact is important because often investigators cannot control the proportions of paternally and maternally informative families. In conclusion, it is possible to reliably detect sex differences in recombination fraction. Copyright 2004 S. Karger AG, Basel

Blood chemistry and hematocrit of captive and wild canvasbacks

USGS Publications Warehouse

Perry, M.C.; Obrecht, H.H.; Williams, B.K.; Kuenzel, W.J.

1986-01-01

Blood chemistry and packed cell volume (PCV) did not vary among groups of captive canvasbacks (Aythya valisineria) maintained ad libitum on 5 diets varying in metabolizable energy (ME) and protein. Ducks fed low quality diets increased their consumption so that all ducks were obtaining similar amounts of energy and protein. Some variables, including cholesterol, were found to differ between the sexes and ages of captive ducks. Seasonal differences were detected in the blood chemistry of captive canvasbacks. Four of the 5 enzyme values increased from October to January and then declined to April. PCV increased from 45 in October to 51 in April. Overall, blood chemistry values and PCV's were highly variable and did not appear to be good discriminators for age, sex, and diet of captive canvasbacks. Differences detected between captive and wild canvasbacks were attributed to increased stress of wild ducks during handling.

Do Predictors of Career Success Differ between Swedish Women and Men? Data from the Swedish Longitudinal Occupational Survey of Health (SLOSH).

PubMed

Nyberg, Anna; Magnusson Hanson, Linda L; Leineweber, Constanze; Johansson, Gunn

2015-01-01

The aim of this prospective study was to explore predictors of objective career success among Swedish women and men, focussing on gender differences. Data were drawn from the 2008 and 2010 waves of the Swedish Longitudinal Occupational Survey of Health (SLOSH) with a total of 3670 female and 2773 male participants. Odds ratios and 95% confidence intervals for job promotion and an above-average salary increase between 2008 and 2010 were obtained through binary logistic regression analyses. Individual and organisational factors measured in 2008 were used as predictors in analyses stratified by sex. Mutual adjustment was performed for these variables, as well as for labour market sector and staff category at baseline. In both sexes, younger age predicted both job promotion and an above-average salary increase. Job promotion was also in both sexes predicted by being part of decision-making processes, having conflicts with superiors, and being eager to advance. Furthermore, promotion was predicted by, among men, being educated to post-graduate level and having an open coping strategy and, among women, working >60 hours/week. An above-average salary increase was predicted in both sexes by having a university education. Postgraduate education, having children living at home, and being very motivated to advance predicted an above-average salary increase among women, as did working 51-60 hours/week and being part of decision-making processes in men. Gender differences were seen in several predictors. In conclusion, the results support previous findings of gender differences in predictors of career success. A high level of education, motivation to advance, and procedural justice appear to be more important predictors of career success among women, while open coping was a more important predictor among men.

Do Predictors of Career Success Differ between Swedish Women and Men? Data from the Swedish Longitudinal Occupational Survey of Health (SLOSH)

PubMed Central

Nyberg, Anna; Johansson, Gunn

2015-01-01

The aim of this prospective study was to explore predictors of objective career success among Swedish women and men, focussing on gender differences. Data were drawn from the 2008 and 2010 waves of the Swedish Longitudinal Occupational Survey of Health (SLOSH) with a total of 3670 female and 2773 male participants. Odds ratios and 95% confidence intervals for job promotion and an above-average salary increase between 2008 and 2010 were obtained through binary logistic regression analyses. Individual and organisational factors measured in 2008 were used as predictors in analyses stratified by sex. Mutual adjustment was performed for these variables, as well as for labour market sector and staff category at baseline. In both sexes, younger age predicted both job promotion and an above-average salary increase. Job promotion was also in both sexes predicted by being part of decision-making processes, having conflicts with superiors, and being eager to advance. Furthermore, promotion was predicted by, among men, being educated to post-graduate level and having an open coping strategy and, among women, working >60 hours/week. An above-average salary increase was predicted in both sexes by having a university education. Postgraduate education, having children living at home, and being very motivated to advance predicted an above-average salary increase among women, as did working 51–60 hours/week and being part of decision-making processes in men. Gender differences were seen in several predictors. In conclusion, the results support previous findings of gender differences in predictors of career success. A high level of education, motivation to advance, and procedural justice appear to be more important predictors of career success among women, while open coping was a more important predictor among men. PMID:26501351

Sexual motivations and engagement in sexual behavior during the transition to college.

PubMed

Patrick, Megan E; Lee, Christine M

2010-06-01

Motivations for and against sex are salient predictors of engaging in or abstaining from sex in cross-sectional studies. Participants (N = 637, 41.4% male) provided data on their motivations for and against sex and lifetime sexual behavior prior to entering college and six months into the first year in college. Longitudinal data were used to examine differences on motivations for and against sex reported the summer before college entrance for students who continued to abstain (Nevers, 44.7%), transitioned to sexual behavior in the following months (Transitioners, 11.0%), and who were previously sexually active (Actives, 44.3%). Multivariate analysis of variance analyses indicated that Transitioners evidenced mean-level differences in motivations surrounding sex (greater intimacy and enhancement motives for sex, lower values motives against sex) prior to their behavioral initiation compared to Nevers. In addition, Transitioners reported greater changes in motivations from pre-college to the six-month follow-up, including increased enhancement motivations for sex and decreased values and not ready motivations against sex. Men reported more important motivations for sex and less important motivations against sex than women, with an interaction showing that sexually experienced women reported more important intimacy motivations and sexually inexperienced men reported more important coping motivations for sex. Identifying salient motivations associated with imminent changes in sexual behavior may support the development of sexual health promotion programs that seek to reach sexually inexperienced individuals at important times of transition.

[Chinese Total Diet Study in 2000. Cadium intakes by different age-sex population groups].

PubMed

Zhang, Lei; Gao, Junquan; Li, Xiaowei

2008-05-01

To estimate the dietary cadium intakes by different age-sex groups in China. The cadium concentrations of food sample from 3rd Chinese total diet study were determined, and then combine these data with the food consumption by population of ten age-sex groups, The cadium intakes, and its distribution and dietary sources were obtained. It was found that the mean and median concentrations of cadium in all food samples were 0.046 and 0.006 mg/kg, respectively. The cadium contents in shellfish and liver were far higher than other food staffs. The cadium intakes by different age-sex groups were estimated to be 12.0 - 25.9 microg/day, ranged from 30.3% to 67.0% of PTWI. The individual dietary cadium intakes by 14% children in 2 - 7 years old group exceed PTWI. Cereals, vegetables and seafood were the main sources of cadium exposure, and contributed about 80% of total intakes. Although the dietary cadium intakes by different age-sex groups are all lower than PTWI, they are increased in the past decade. Moreover, in some provinces, the cadium burden of people is heavy.

Sex differences in neurochemical markers that correlate with behavior in aging mice.

PubMed

Frick, K M; Burlingame, L A; Delaney, S S; Berger-Sweeney, J

2002-01-01

Sex differences in neurochemical markers that correlate with behavior in aging mice NEUROBIOL AGING. We examined whether the enzymatic activities of choline acetyltransferase (ChAT) and glutamic acid decarboxylase (GAD) were altered similarly with age in male and female mice, and whether these changes were correlated with age-related alterations in memory and anxiety. ChAT and GAD activities were measured in neocortex, hippocampus, and striatum of behaviorally characterized male and female C57BL/6 mice (5, 17, and 25 months). Generally, ChAT activity was increased, and GAD activity decreased, with age. However, disparate changes were revealed between the sexes; activities of both enzymes were decreased in 17-month males, whereas alterations in females were not observed until 25-months. Furthermore, enzyme-behavior correlations differed between the sexes; in males, ChAT activity was related to one behavioral task, whereas in females, activities of both enzymes were correlated with multiple tasks. Significant enzyme-behavior correlations were most evident at 17 months of age, likely the result of behavioral and enzymatic sex differences at this age. These data represent the first comprehensive report illustrating differential alterations of ChAT and GAD activities in aging male and female mice.

Relationship between age and elite marathon race time in world single age records from 5 to 93 years

PubMed Central

2014-01-01

Background The aims of the study were (i) to investigate the relationship between elite marathon race times and age in 1-year intervals by using the world single age records in marathon running from 5 to 93 years and (ii) to evaluate the sex difference in elite marathon running performance with advancing age. Methods World single age records in marathon running in 1-year intervals for women and men were analysed regarding changes across age for both men and women using linear and non-linear regression analyses for each age for women and men. Results The relationship between elite marathon race time and age was non-linear (i.e. polynomial regression 4th degree) for women and men. The curve was U-shaped where performance improved from 5 to ~20 years. From 5 years to ~15 years, boys and girls performed very similar. Between ~20 and ~35 years, performance was quite linear, but started to decrease at the age of ~35 years in a curvilinear manner with increasing age in both women and men. The sex difference increased non-linearly (i.e. polynomial regression 7th degree) from 5 to ~20 years, remained unchanged at ~20 min from ~20 to ~50 years and increased thereafter. The sex difference was lowest (7.5%, 10.5 min) at the age of 49 years. Conclusion Elite marathon race times improved from 5 to ~20 years, remained linear between ~20 and ~35 years, and started to increase at the age of ~35 years in a curvilinear manner with increasing age in both women and men. The sex difference in elite marathon race time increased non-linearly and was lowest at the age of ~49 years. PMID:25120915

Acceptance of sexual minorities, discrimination, social capital and health and well-being: a cross-European study among members of same-sex and opposite-sex couples.

PubMed

van der Star, Arjan; Bränström, Richard

2015-08-21

Awareness of health disparities based on sexual orientation has increased in the past decades, and many official public health agencies throughout Europe call for programs addressing the specific needs of lesbian, gay and bisexual (LGB) individuals. However, the acceptance of LGB individuals varies significantly in different countries, which potentially influences health and well-being in this population. We explored differences in self-rated health and subjective well-being between individuals living in same-sex and opposite-sex couples. We also examined the effects of discrimination and country-level variations in LGB acceptance on health and well-being and the potential mediating role of social capital in these associations. Using the 2010 European Social Survey (n = 50,781), 315 individuals living with a same-sex partner were matched and compared with an equal number of individuals living in opposite-sex couples. We performed structural equation modeling analyses to estimate path coefficients, mediations and interactions. LGB acceptance was significantly related to better self-rated health and subjective well-being among all individuals, and these associations were partially mediated by individual social capital. No differences in these associations were found between individuals living in same-sex and opposite-sex couples. Sexuality-based discrimination had an additional significantly negative effect on self-related health and subjective well-being. The findings of this study suggest a negative association between exposure to discrimination based on sexual orientation and both health and well-being of individuals living in same-sex couples. Members of same-sex couples and opposite-sex couples alike may benefit from living in societies with a high level of LGB acceptance to promote better health and well-being.

Traditional agricultural practices and the sex ratio today

PubMed Central

2018-01-01

We study the historical origins of cross-country differences in the male-to-female sex ratio. Our analysis focuses on the use of the plough in traditional agriculture. In societies that did not use the plough, women tended to participate in agriculture as actively as men. By contrast, in societies that used the plough, men specialized in agricultural work, due to the physical strength needed to pull the plough or control the animal that pulls it. We hypothesize that this difference caused plough-using societies to value boys more than girls. Today, this belief is reflected in male-biased sex ratios, which arise due to sex-selective abortion or infanticide, or gender-differences in access to family resources, which results in higher mortality rates for girls. Testing this hypothesis, we show that descendants of societies that traditionally practiced plough agriculture today have higher average male-to-female sex ratios. We find that this effect systematically increases in magnitude and statistical significance as one looks at older cohorts. Estimates using instrumental variables confirm our findings from multivariate OLS analysis. PMID:29338023

Cross-sectional geometry of Pecos Pueblo femora and tibiae--a biomechanical investigation: II. Sex, age, side differences.

PubMed

Ruff, C B; Hayes, W C

1983-03-01

Intra-populational variation in cross-sectional geometric properties of the femur and tibia are investigated in the Pecos Pueblo skeletal sample. Sex differences in geometric parameters suggest that male lower limb bones are more adapted for A-P bending, females for M-L bending. Proposed explanations for this finding include sexual dimorphism in pelvic structure and culturally prescribed sex-related activities at Pecos. With aging, both males and females undergo endosteal resorption and cortical thinning, greater among females. Both sexes also demonstrate an increase with age in subperiosteal area and second moments of area, supporting results reported in some studies of modern population samples. Sex and site-specific remodeling of the femur and tibia with aging also occur. These localized remodeling changes appear to selectively conserve more compact cortical bone in areas of high mechanical stress. Side differences in cross-sectional geometric properties indicate that left lower limb bones are generally larger than right lower limb bones, with asymmetry greater among females. In particular, left femora and tibiae are relatively stronger in A-P bending, again more so in females.

The Best Timing of Mate Search in Armadillidium vulgare (Isopoda, Oniscidea)

PubMed Central

Beauché, Fanny; Richard, Freddie-Jeanne

2013-01-01

Mate choice is mediated by many components with the criteria varying across the animal kingdom. Chemical cues used for mate attractiveness can also reflect mate quality. Regarding the gregarious species Armadillidium vulgare (isopod crustacean), we tested whether individuals can discriminate conspecifics at two different levels (between sex and physiological status) based on olfactory perception. Tested conspecifics were individuals of the same or opposite sex, with the females at different moult stages. We found that the attractiveness of individuals was mediated by short-distance chemical cues and tested individuals were able to discriminate and prefer individuals of the opposite sex. Moreover, male preference to female increased during their moulting status as they matured. Males were particularly more attracted by females with appearing white calcium plates, which corresponds to the beginning of their higher receptivity period. These differences in attractiveness due to sex and physiological status are likely to shape the composition of aggregates and facilitate mate finding and optimize the reproductive success for both males and females. Thus aggregation pheromones could be linked to sex pheromones in terrestrial isopods. PMID:23469225

Assessment of Spirituality as a Function of Quality of Life In Prostate Cancer Patients

DTIC Science & Technology

1999-10-01

Viral infection or bacteria Genetics Worrying or stress Having sex with different partners Having sex without wearing a condom Masturbating God teaching...since diagnosis, the majority noted that their religious belief and/or practices had increased. About five men in all of the sessions indicated they were

Child/Adolescent Abuse and Suicidal Behavior: Are They Sex Related?

ERIC Educational Resources Information Center

Gal, Gilad; Levav, Itzhak; Gross, Raz

2012-01-01

The association between childhood and adolescent abuse and suicidal behavior, and the possible contribution of abuse to sex differences in non lethal suicidal behavior, was investigated. Data were extracted from the Israel-based component of the WHO World Mental Health Survey (Kessler & Utsun, 2008a). Increased risk for ideation, plan, and…

Hepatitis B surface antigen gene expression is regulated by sex steroids and glucocorticoids in transgenic mice.

PubMed Central

Farza, H; Salmon, A M; Hadchouel, M; Moreau, J L; Babinet, C; Tiollais, P; Pourcel, C

1987-01-01

We have investigated the basis for liver-specific and sex-linked expression of hepatitis B surface antigen (HBsAg) gene in transgenic mice by monitoring the level of liver HBsAg mRNA and serum HBsAg at different stages of development and in response to sex-hormone regulation. Transcription of the HBsAg gene starts at day 15 of development, together with that of the albumin gene, and reaches a comparable level at birth. HBsAg mRNA level and HBsAg production are parallel in males and females during prenatal development and until the first month of life, but HBsAg gene expression increases 5-10 times in males at puberty. After castration, the level of expression decreases dramatically in both males and females and is subsequently increased by injection of testosterone or estradiol. Glucocorticoids also regulated positively expression of the HBsAg gene. Our results suggest that sex hormones play a role in hepatitis B virus gene expression during natural infection and could explain the difference in incidence of chronic carriers between men and women. Images PMID:3469661

Sex Differences in Gamma Band Functional Connectivity Between the Frontal Lobe and Cortical Areas During an Auditory Oddball Task, as Revealed by Imaginary Coherence Assessment.

PubMed

Fujimoto, Toshiro; Okumura, Eiichi; Kodabashi, Atsushi; Takeuchi, Kouzou; Otsubo, Toshiaki; Nakamura, Katsumi; Yatsushiro, Kazutaka; Sekine, Masaki; Kamiya, Shinichiro; Shimooki, Susumu; Tamura, Toshiyo

2016-01-01

We studied sex-related differences in gamma oscillation during an auditory oddball task, using magnetoencephalography and electroencephalography assessment of imaginary coherence (IC). We obtained a statistical source map of event-related desynchronization (ERD) / event-related synchronization (ERS), and compared females and males regarding ERD / ERS. Based on the results, we chose respectively seed regions for IC determinations in low (30-50 Hz), mid (50-100 Hz) and high gamma (100-150 Hz) bands. In males, ERD was increased in the left posterior cingulate cortex (CGp) at 500 ms in the low gamma band, and in the right caudal anterior cingulate cortex (cACC) at 125 ms in the mid-gamma band. ERS was increased in the left rostral anterior cingulate cortex (rACC) at 375 ms in the high gamma band. We chose the CGp, cACC and rACC as seeds, and examined IC between the seed and certain target regions using the IC map. IC changes depended on the height of the gamma frequency and the time window in the gamma band. Although IC in the mid and high gamma bands did not show sex-specific differences, IC at 30-50 Hz in males was increased between the left rACC and the frontal, orbitofrontal, inferior temporal and fusiform target regions. Increased IC in males suggested that males may acomplish the task constructively, analysingly, emotionally, and by perfoming analysis, and that information processing was more complicated in the cortico-cortical circuit. On the other hand, females showed few differences in IC. Females planned the task with general attention and economical well-balanced processing, which was explained by the higher overall functional cortical connectivity. CGp, cACC and rACC were involved in sex differences in information processing and were likely related to differences in neuroanatomy, hormones and neurotransmitter systems.

[Sexual behavior and sources of information about sex among male adolescents: An 8-year follow-up].

PubMed

Korkmaz Cetin, Saniye; Bildik, Tezan; Erermiş, Serpil; Demiral, Nagehan; Ozbaran, Burcu; Tamar, Müge; Aydin, Cahide

2008-01-01

This study aimed to determine the changes over time in sexual attitude and behavior among adolescents, and to measure the effect of sources information about sex on these changes. This study was conducted in 2 stages, the first in 1996 and the second in 2004. In all, 392 male tenth grade students (150 in the first stage and 242 in the second stage) were evaluated. A personal information questionnaire developed by the authors was used to collect sociodemographic data, including sexual behavior, sexual attitude, and sources of information about sex. The findings show that there was a significant increase in intercourse and flirting behavior from 1996 to 2004, although no significant difference in masturbation was observed. Additionally, the number of male adolescents that reported family and pornographic films as their sources of information about sex increased 1.6-fold and 2.9-fold, respectively. A significant relationship between watching pornographic films and engaging in sexual intercourse was noted. The number of male adolescents age mean 16, engaging in sexual intercourse increased between 1996 and 2004. Pornographic films were observed to be the most common source of information about sex and also predicted the probability of adolescents having sex. Findings that indicate the need for better and more accurate sources of information about sex. The availability of good quality information about sex is critical to the development of the sexual identity and mental health of male adolescents.

Sex-specific microRNA expression networks in an acute mouse model of ozone-induced lung inflammation.

PubMed

Fuentes, Nathalie; Roy, Arpan; Mishra, Vikas; Cabello, Noe; Silveyra, Patricia

2018-05-08

Sex differences in the incidence and prognosis of respiratory diseases have been reported. Studies have shown that women are at increased risk of adverse health outcomes from air pollution than men, but sex-specific immune gene expression patterns and regulatory networks have not been well studied in the lung. MicroRNAs (miRNAs) are environmentally sensitive posttranscriptional regulators of gene expression that may mediate the damaging effects of inhaled pollutants in the lung, by altering the expression of innate immunity molecules. Male and female mice of the C57BL/6 background were exposed to 2 ppm of ozone or filtered air (control) for 3 h. Female mice were also exposed at different stages of the estrous cycle. Following exposure, lungs were harvested and total RNA was extracted. We used PCR arrays to study sex differences in the expression of 84 miRNAs predicted to target inflammatory and immune genes. We identified differentially expressed miRNA signatures in the lungs of male vs. female exposed to ozone. In silico pathway analyses identified sex-specific biological networks affected by exposure to ozone that ranged from direct predicted gene targeting to complex interactions with multiple intermediates. We also identified differences in miRNA expression and predicted regulatory networks in females exposed to ozone at different estrous cycle stages. Our results indicate that both sex and hormonal status can influence lung miRNA expression in response to ozone exposure, indicating that sex-specific miRNA regulation of inflammatory gene expression could mediate differential pollution-induced health outcomes in men and women.

The Impact of Sex Work Interruption on Blood-Derived T Cells in Sex Workers from Nairobi, Kenya.

PubMed

Omollo, Kenneth; Boily-Larouche, Geneviève; Lajoie, Julie; Kimani, Makobu; Cheruiyot, Julianna; Kimani, Joshua; Oyugi, Julius; Fowke, Keith Raymond

Unprotected sexual intercourse exposes the female genital tract (FGT) to semen-derived antigens, which leads to a proinflammatory response. Studies have shown that this postcoital inflammatory response can lead to recruitment of activated T cells to the FGT, thereby increasing risk of HIV infection. The purpose of this study was to evaluate the impact of sex work on activation and memory phenotypes of peripheral T cells among female sex workers (FSW) from Nairobi, Kenya. Thirty FSW were recruited from the Pumwani Sex Workers Cohort, 10 in each of the following groups: HIV-exposed seronegative (at least 7 years in active sex work), HIV positive, and New Negative (HIV negative, less than 3 years in active sex work). Blood was obtained at three different phases (active sex work, abstinence from sex work-sex break, and following resumption of sex work). Peripheral blood mononuclear cells were isolated and stained for phenotypic markers (CD3, CD4, CD8, and CD161), memory phenotype markers (CD45RA and CCR7), activation markers (CD69, HLA-DR, and CD95), and the HIV coreceptor (CCR5). T-cell populations were compared between groups. In HIV-positive women, CD8+CCR5+ T cells declined at the sex break period, while CD4+CD161+ T cells increased when returning to sex work. All groups showed no significant changes in systemic T-cell activation markers following the interruption of sex work, however, significant reductions in naive CD8+ T cells were noted. For each of the study points, HIV positives had higher effector memory and CD8+CD95+ T cells and lower naive CD8+ T cells than the HIV-uninfected groups. Interruption of sex work had subtle effects on systemic T-cell memory phenotypes.

The Duality of Oral Sex for Men Who Have Sex with Men: An Examination Into the Increase of Sexually Transmitted Infections Amid the Age of HIV Prevention.

PubMed

Glynn, Tiffany R; Operario, Don; Montgomery, Madeline; Almonte, Alexi; Chan, Philip A

2017-06-01

Several studies suggest that the increase in sexually transmitted infections (STIs) among men who have sex with men (MSM) could be due, in part, to human immunodeficiency virus (HIV) risk reduction strategies, which include engaging in oral sex over anal sex. The aims of this study were to evaluate oral sex behaviors and STI diagnoses and to investigate the potential dual role of oral sex as being protective for HIV, yet perpetuating STI transmission among MSM. We analyzed records from 871 MSM presenting to the Rhode Island STI Clinic between 2012 and 2015. We compared outcomes in men engaging in two HIV protective oral sex behaviors: (1) HIV/STI outcomes by men engaging only in oral sex versus those that did not, and (2) HIV/STI outcomes by men engaging in condomless oral sex with 100% condom use for all other sex acts versus those that did not. Men engaging in HIV protective oral sex behaviors were more likely to be HIV negative compared to men not engaging in them (99% vs. 93%, p < 0.01). In contrast, there was no significant difference in STI diagnoses between those that engaged in HIV protective oral sex behaviors and those that did not. The findings provide evidence to support the unique duality of oral sex: decreased risk for HIV and perpetuation of STI risk. Promotion of routine STI testing, including extragenital sites, is critical to address STI prevention among MSM. In the age of HIV prevention, addressing the ambiguous risks of discrete sex acts would be beneficial for both HIV and STI prevention education for MSM.

The Duality of Oral Sex for Men Who Have Sex with Men: An Examination Into the Increase of Sexually Transmitted Infections Amid the Age of HIV Prevention

PubMed Central

Glynn, Tiffany R.; Operario, Don; Montgomery, Madeline; Almonte, Alexi

2017-01-01

Abstract Several studies suggest that the increase in sexually transmitted infections (STIs) among men who have sex with men (MSM) could be due, in part, to human immunodeficiency virus (HIV) risk reduction strategies, which include engaging in oral sex over anal sex. The aims of this study were to evaluate oral sex behaviors and STI diagnoses and to investigate the potential dual role of oral sex as being protective for HIV, yet perpetuating STI transmission among MSM. We analyzed records from 871 MSM presenting to the Rhode Island STI Clinic between 2012 and 2015. We compared outcomes in men engaging in two HIV protective oral sex behaviors: (1) HIV/STI outcomes by men engaging only in oral sex versus those that did not, and (2) HIV/STI outcomes by men engaging in condomless oral sex with 100% condom use for all other sex acts versus those that did not. Men engaging in HIV protective oral sex behaviors were more likely to be HIV negative compared to men not engaging in them (99% vs. 93%, p < 0.01). In contrast, there was no significant difference in STI diagnoses between those that engaged in HIV protective oral sex behaviors and those that did not. The findings provide evidence to support the unique duality of oral sex: decreased risk for HIV and perpetuation of STI risk. Promotion of routine STI testing, including extragenital sites, is critical to address STI prevention among MSM. In the age of HIV prevention, addressing the ambiguous risks of discrete sex acts would be beneficial for both HIV and STI prevention education for MSM. PMID:28530499

Photoperiod affects the expression of sex and species differences in leukocyte number and leukocyte trafficking in congeneric hamsters.

PubMed

Bilbo, S D; Dhabhar, F S; Viswanathan, K; Saul, A; Nelson, R J

2003-11-01

Sex differences in immune function are well documented. These sex differences may be modulated by social and environmental factors. Individuals of polygynous species generally exhibit more pronounced sex differences in immune parameters than individuals of monogamous species, often displaying an energetic trade-off between enhanced immunity and high mating success. During winter, animals contend with environmental conditions (e.g. low temperatures and decreased food availability) that evoke energetic-stress responses; many mammals restrict reproduction in response to photoperiod as part of an annual winter coping strategy. To test the hypothesis that extant sex and species differences in immune surveillance may be modulated by photoperiod, we examined leukocyte numbers in males and females of two closely related hamster species (Phodopus). As predicted, uniparental P. sungorus exhibited a robust sex difference, with total white blood cells, total lymphocytes, T cells, and B cells higher in females than males, during long days when reproduction occurs, but not during short days when reproduction usually stops. In contrast, biparental male and female P. campbelli exhibited comparable leukocyte numbers during both long and short days. To study sex differences in stress responses, we also examined immune cell trafficking in response to an acute (2 h) restraint stressor. During stressful challenges, it appears beneficial for immune cells to exit the blood and move to primary immune defense areas such as the skin, in preparation for potential injury or infection. Acute stress moved lymphocytes and monocytes out of the blood in all animals. Blood cortisol concentrations were increased in P. sungorus females compared to males at baseline (52%) and in response to restraint stress (38%), but only in long days. P. campbelli males and females exhibited comparable blood cortisol and stress responses during both long and short days. Our results suggest that interactions among social factors and the environment play a significant role in modulating sex and seasonal alterations in leukocyte numbers and stress responses.

Epigenetics and sex differences in the brain: A genome-wide comparison of histone-3 lysine-4 trimethylation (H3K4me3) in male and female mice.

PubMed

Shen, Erica Y; Ahern, Todd H; Cheung, Iris; Straubhaar, Juerg; Dincer, Aslihan; Houston, Isaac; de Vries, Geert J; Akbarian, Schahram; Forger, Nancy G

2015-06-01

Many neurological and psychiatric disorders exhibit gender disparities, and sex differences in the brain likely explain some of these effects. Recent work in rodents points to a role for epigenetics in the development or maintenance of neural sex differences, although genome-wide studies have so far been lacking. Here we review the existing literature on epigenetics and brain sexual differentiation and present preliminary analyses on the genome-wide distribution of histone-3 lysine-4 trimethylation in a sexually dimorphic brain region in male and female mice. H3K4me3 is a histone mark primarily organized as 'peaks' surrounding the transcription start site of active genes. We microdissected the bed nucleus of the stria terminalis and preoptic area (BNST/POA) in adult male and female mice and used ChIP-Seq to compare the distribution of H3K4me3 throughout the genome. We found 248 genes and loci with a significant sex difference in H3K4me3. Of these, the majority (71%) had larger H3K4me3 peaks in females. Comparisons with existing databases indicate that genes and loci with increased H3K4me3 in females are associated with synaptic function and with expression atlases from related brain areas. Based on RT-PCR, only a minority of genes with a sex difference in H3K4me3 has detectable sex differences in expression at baseline conditions. Together with previous findings, our data suggest that there may be sex biases in the use of epigenetic marks. Such biases could underlie sex differences in vulnerabilities to drugs or diseases that disrupt specific epigenetic processes. Copyright © 2014 Elsevier Inc. All rights reserved.

Sex differences in macronutrient intake and adherence to dietary recommendations: findings from the UK Biobank.

PubMed

Bennett, Elizabeth; Peters, Sanne A E; Woodward, Mark

2018-04-24

To characterise sex differences in macronutrient intakes and adherence to dietary recommendations in the UK Biobank population. Cross-sectional population-based study. UK Biobank Resource. 210 106 (52.5% women) individuals with data on dietary behaviour. Women-to-men mean differences in nutrient intake in grams and as a percentage of energy and women-to-men ORs in non-adherence, adjusting for age, socioeconomic status and ethnicity. There were sex differences in energy intake and distribution. Men had greater intakes of energy and were less likely to have energy intakes above the estimated average requirement compared with women. Small, but significant, sex differences were found in the intakes of all macronutrients. For all macronutrients, men had greater absolute intakes while women had greater intakes as a percentage of energy. Women were more likely to have intakes that exceeded recommendations for total fat, saturated fat and total sugar. Men were less likely to achieve the minimum recommended intakes for protein, polyunsaturated fat and total carbohydrate. Over 95% of men and women were non-adherent to fibre recommendations. Sex differences in dietary intakes were moderated by age and to some extent by socioeconomic status. There are significant sex differences in adherence to dietary recommendations, particularly for sugar. However, given the increased focus on food groups and dietary patterns for nutritional policy, these differences alone may not be sufficient for policy and health promotion. Future studies that are able to explore the sex differences in intakes of different food groups that are risk factors for diet-related diseases are warranted to improve the current understanding of the differential impact of diet on health in women and men. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Sex differences in autonomic function following maximal exercise.

PubMed

Kappus, Rebecca M; Ranadive, Sushant M; Yan, Huimin; Lane-Cordova, Abbi D; Cook, Marc D; Sun, Peng; Harvey, I Shevon; Wilund, Kenneth R; Woods, Jeffrey A; Fernhall, Bo

2015-01-01

Heart rate variability (HRV), blood pressure variability, (BPV) and heart rate recovery (HRR) are measures that provide insight regarding autonomic function. Maximal exercise can affect autonomic function, and it is unknown if there are sex differences in autonomic recovery following exercise. Therefore, the purpose of this study was to determine sex differences in several measures of autonomic function and the response following maximal exercise. Seventy-one (31 males and 40 females) healthy, nonsmoking, sedentary normotensive subjects between the ages of 18 and 35 underwent measurements of HRV and BPV at rest and following a maximal exercise bout. HRR was measured at minute one and two following maximal exercise. Males have significantly greater HRR following maximal exercise at both minute one and two; however, the significance between sexes was eliminated when controlling for VO2 peak. Males had significantly higher resting BPV-low-frequency (LF) values compared to females and did not significantly change following exercise, whereas females had significantly increased BPV-LF values following acute maximal exercise. Although males and females exhibited a significant decrease in both HRV-LF and HRV-high frequency (HF) with exercise, females had significantly higher HRV-HF values following exercise. Males had a significantly higher HRV-LF/HF ratio at rest; however, both males and females significantly increased their HRV-LF/HF ratio following exercise. Pre-menopausal females exhibit a cardioprotective autonomic profile compared to age-matched males due to lower resting sympathetic activity and faster vagal reactivation following maximal exercise. Acute maximal exercise is a sufficient autonomic stressor to demonstrate sex differences in the critical post-exercise recovery period.

Using sex differences in the developing brain to identify nodes of influence for seizure susceptibility and epileptogenesis.

PubMed

Kight, Katherine E; McCarthy, Margaret M

2014-12-01

Sexual differentiation of the developing brain organizes the neural architecture differently between males and females, and the main influence on this process is exposure to gonadal steroids during sensitive periods of prenatal and early postnatal development. Many molecular and cellular processes are influenced by steroid hormones in the developing brain, including gene expression, cell birth and death, neurite outgrowth and synaptogenesis, and synaptic activity. Perturbations in these processes can alter neuronal excitability and circuit activity, leading to increased seizure susceptibility and the promotion of pathological processes that constitute epileptogenesis. In this review, we will provide a general overview of sex differences in the early developing brain that may be relevant for altered seizure susceptibility in early life, focusing on limbic areas of the brain. Sex differences that have the potential to alter the progress of epileptogenesis are evident at molecular and cellular levels in the developing brain, and include differences in neuronal excitability, response to environmental insult, and epigenetic control of gene expression. Knowing how these processes differ between the sexes can help us understand fundamental mechanisms underlying gender differences in seizure susceptibility and epileptogenesis. Copyright © 2014 Elsevier Inc. All rights reserved.

Influences of Mating Group Composition on the Behavioral Time-Budget of Male and Female Alpine Ibex (Capra ibex) during the Rut

PubMed Central

Tettamanti, Federico; Viblanc, Vincent A.

2014-01-01

During the rut, polygynous ungulates gather in mixed groups of individuals of different sex and age. Group social composition, which may vary on a daily basis, is likely to have strong influences on individual’s time-budget, with emerging properties at the group-level. To date, few studies have considered the influence of group composition on male and female behavioral time budget in mating groups. Focusing on a wild population of Alpine ibex, we investigated the influence of group composition (adult sex ratio, the proportion of dominant to subordinate males, and group size) on three behavioral axes obtained by Principal Components Analysis, describing male and female group time-budget. For both sexes, the first behavioral axis discerned a trade-off between grazing and standing/vigilance behavior. In females, group vigilance behavior increased with increasingly male-biased sex ratio, whereas in males, the effect of adult sex ratio on standing/vigilance behavior depended on the relative proportion of dominant males in the mating group. The second axis characterized courtship and male-male agonistic behavior in males, and moving and male-directed agonistic behavior in females. Mating group composition did not substantially influence this axis in males. However, moving and male-directed agonistic behavior increased at highly biased sex ratios (quadratic effect) in females. Finally, the third axis highlighted a trade-off between moving and lying behavior in males, and distinguished moving and female-female agonistic behavior from lying behavior in females. For males, those behaviors were influenced by a complex interaction between group size and adult sex ratio, whereas in females, moving and female-female agonistic behaviors increased in a quadratic fashion at highly biased sex ratios, and also increased with increasing group size. Our results reveal complex behavioral trade-offs depending on group composition in the Alpine ibex, and emphasize the importance of social factors in influencing behavioral time-budgets of wild ungulates during the rut. PMID:24416453

Sex-Based Differences as a Predictor of Recovery Trajectories in Young Athletes After a Sports-Related Concussion.

PubMed

Ono, Kim E; Burns, Thomas G; Bearden, Donald J; McManus, Susan M; King, Harold; Reisner, Andrew

2016-03-01

To date, few studies have delineated clear sex-based differences in symptom resolution after a sports-related concussion (SRC), and equivocal results have been identified in sex-based differences on baseline assessments. To assess whether female athletes displayed prolonged recovery and more symptoms at baseline and after an SRC compared with male athletes. Cohort study; Level of evidence, 3. The current study assessed 135 male and 41 female athletes (10-18 years old) who participated in high-impact sports in metropolitan Atlanta middle and high schools. All athletes completed a baseline assessment and at least 1 postconcussion assessment from the Immediate Post-Concussion Assessment and Cognitive Testing battery. Longitudinal hierarchical linear modeling was employed to examine individual-level variables and their associations with adolescents' rates of recovery in concussive symptoms after controlling for age and number of prior concussions. Aggregate symptoms were rated as higher in female athletes compared with male athletes at baseline (mean ± SD: females, 13.49 ± 11.20; males, 4.88 ± 8.74; F(1,175) = 10.59, P < .001) and immediately after a concussion (females: 16.75 ± 18.08; males: 10.58 ± 14.21; F(1,175) = 3.99, P = .05). There were no group differences in the slope of recovery between male and female athletes, indicating generally similar trajectories of change for both groups. Post hoc analyses revealed higher baseline levels of migraine and neuropsychological symptoms in female athletes. Although female athletes in the current study reported increased symptoms, identical recovery patterns were observed in both sexes, suggesting that sex-based differences in concussion recovery are better explained by increased symptom frequency among female athletes when compared with their male counterparts. © 2015 The Author(s).

Stroke and myocardial infarction: a comparative systematic evaluation of gender-specific analysis, funding and authorship patterns in cardiovascular research.

PubMed

Oertelt-Prigione, Sabine; Wiedmann, Silke; Endres, Matthias; Nolte, Christian H; Regitz-Zagrosek, Vera; Heuschmann, Peter

2011-01-01

Major gender differences exist in cardiovascular diseases and lead to different outcomes in women and men. However, attention and incorporation of sex-/gender-specific research might vary among disciplines. We therefore conducted a systematic review comparing publication characteristics and trends between stroke and myocardial infarction (MI) with respect to sex- and gender-related aspects. A systematic literature search was performed in PubMed to identify gender-/sex-related articles published for stroke and MI between 1977 and 2008. A specifically designed text mining program was used, and all literature was rated by two independent investigators. Publications were classified according to type of research performed, publication year, funding, geographical location, and gender of first and last authors. 962 articles were retrieved and limited to 405 (42%) gender-relevant publications; 131 on stroke and 274 on MI. Type of performed research differed, especially in disease management, which received little attention (17%) in stroke, while representing the major focus in MI (40%). In both areas, clinical presentation received little attention (3 and 5%). Although publications progressively increased in both fields, an 8- to 10-year time gap emerged for stroke compared to MI. Last authors in both areas were predominantly men, but female last authorship is increasing more significantly over time in the field of stroke. Research on sex and gender differences in MI and stroke is largely underfunded, particularly by the EU. The data demonstrate how sex-/gender-specific research differs between specialties, most likely due to the diverse interest, funding opportunities and authorship distributions identified. Copyright © 2011 S. Karger AG, Basel.

Chronobiology differs between men and women with cluster headache, clinical phenotype does not.

PubMed

Lund, Nunu; Barloese, Mads; Petersen, Anja; Haddock, Bryan; Jensen, Rigmor

2017-03-14

To describe differences between the sexes in the phenotype of cluster headache (CH) in a large, well-characterized clinical CH population. Patients from the Danish CH survey aged 18-65 years, diagnosed with CH according to International Classification of Headache Disorders, second edition, completed questionnaires and structured interviews. A total of 351 patients with CH participated, with a male:female ratio of 2:1. The diurnal variation of attacks showed moments of peak prominence in men's attack cycle to be advanced by 1 hour compared to women's, despite no difference in self-reported bedtime or chronotype ( p = 0.31). The onset of CH decreased with increasing age for both sexes. Diagnostic delay was numerically longer for men vs women (6.56 vs 5.50 years, p = 0.21); however, more women had previously been misdiagnosed (61.1% vs 45.5%, p < 0.01) and received the correct diagnosis at a tertiary headache center (38.8% vs 20.9%, p < 0.001). Only minor sex differences in clinical characteristics were found but chronic CH was more prevalent in women compared to men (44.0% vs 31.9%, p < 0.05). Despite a similar clinical phenotype, diurnal attack cycle is advanced by 1 hour in men with CH compared to women. Rhythmicity is a defining characteristic of CH and these findings suggest differences in the hypothalamus' influence on attack occurrence between the sexes. In addition, women were more often misdiagnosed and diagnosis in the primary or secondary sector more often failed. Furthermore, women had chronic CH more frequently than men. A long diagnostic delay and frequent misdiagnosis emphasize the need for increased awareness of CH in both sexes. © 2017 American Academy of Neurology.

Mobility and Navigation among the Yucatec Maya: Sex Differences Reflect Parental Investment, Not Mating Competition.

PubMed

Cashdan, Elizabeth; Kramer, Karen L; Davis, Helen E; Padilla, Lace; Greaves, Russell D

2016-03-01

Sex differences in range size and navigation are widely reported, with males traveling farther than females, being less spatially anxious, and in many studies navigating more effectively. One explanation holds that these differences are the result of sexual selection, with larger ranges conferring mating benefits on males, while another explanation focuses on greater parenting costs that large ranges impose on reproductive-aged females. We evaluated these arguments with data from a community of highly monogamous Maya farmers. Maya men and women do not differ in distance traveled over the region during the mate-seeking years, suggesting that mating competition does not affect range size in this monogamous population. However, men's regional and daily travel increases after marriage, apparently in pursuit of resources that benefit families, whereas women reduce their daily travel after marriage. This suggests that parental effort is more important than mating effort in this population. Despite the relatively modest overall sex difference in mobility, Maya men were less spatially anxious than women, thought themselves to be better navigators, and pointed more accurately to distant locations. A structural equation model showed that the sex by marital status interaction had a direct effect on mobility, with a weaker indirect effect of sex on mobility mediated by navigational ability.

Exercise, Appetite and Weight Control: Are There Differences between Men and Women?

PubMed Central

Thackray, Alice E.; Deighton, Kevin; King, James A.; Stensel, David J.

2016-01-01

Recent years have witnessed significant research interest surrounding the interaction among exercise, appetite and energy balance, which has important implications for health. The majority of exercise and appetite regulation studies have been conducted in males. Consequently, opportunities to examine sex-based differences have been limited, but represent an interesting avenue of inquiry considering postulations that men experience greater weight loss after exercise interventions than women. This article reviews the scientific literature relating to the acute and chronic effects of exercise on appetite control in men and women. The consensus of evidence demonstrates that appetite, appetite-regulatory hormone and energy intake responses to acute exercise do not differ between the sexes, and there is little evidence indicating compensatory changes occur after acute exercise in either sex. Limited evidence suggests women respond to the initiation of exercise training with more robust compensatory alterations in appetite-regulatory hormones than men, but whether this translates to long-term differences is unknown. Current exercise training investigations do not support sex-based differences in appetite or objectively assessed energy intake, and increasing exercise energy expenditure elicits at most a partial energy intake compensation in both sexes. Future well-controlled acute and chronic exercise studies directly comparing men and women are required to expand this evidence base. PMID:27657127

Sex Ratio and Reproductive Effort in the Dioecious Juniperus communis subsp. alpina (Suter) Čelak. (Cupressaceae) Along an Altitudinal Gradient

PubMed Central

ORTIZ, PEDRO LUIS; ARISTA, MONTSERRAT; TALAVERA, SALVADOR

2002-01-01

The hypothesis that reproductive cost differs between sexes was tested in Juniperus communis subsp. alpina along an altitudinal gradient. Sex ratio (male : female) increased significantly with elevation, and above 2600 m it was significantly male‐biased. The reproductive effort was markedly greater for females than for males at all elevations. However, over 3 years of study, the growth of the females, measured as elongation of the main axes, was similar to that of the males. In both sexes, growth decreased with increasing elevation. Neither size of the ripe seed cones, nor the number of developed seeds per cone varied with elevation. The percentage of filled seeds was significantly greater at higher elevations indicating more favourable conditions for wind pollination in these stands. However, cone production decreased with elevation and so, reproductive success of J. communis subsp. alpina in Sierra Nevada decreases towards both upper and lower altitudinal distribution limits. The results do not support the hypothesis of differential reproductive cost between sexes; thus, alternative arguments to explain the altitudinal variation of sex ratio are discussed. PMID:12099351

Sex ratio and reproductive effort in the dioecious Juniperus communis subsp. alpina (Suter) Celak. (Cupressaceae) along an altitudinal gradient.

PubMed

Ortiz, Pedro Luis; Arista, Montserrat; Talavera, Salvador

2002-02-01

The hypothesis that reproductive cost differs between sexes was tested in Juniperus communis subsp. alpina along an altitudinal gradient. Sex ratio (male : female) increased significantly with elevation, and above 2,600 m it was significantly male-biased. The reproductive effort was markedly greater for females than for males at all elevations. However, over 3 years of study, the growth of the females, measured as elongation of the main axes, was similar to that of the males. In both sexes, growth decreased with increasing elevation. Neither size of the ripe seed cones, nor the number of developed seeds per cone varied with elevation. The percentage of filled seeds was significantly greater at higher elevations indicating more favourable conditions for wind pollination in these stands. However, cone production decreased with elevation and so, reproductive success of J. communis subsp. alpina in Sierra Nevada decreases towards both upper and lower altitudinal distribution limits. The results do not support the hypothesis of differential reproductive cost between sexes; thus, alternative arguments to explain the altitudinal variation of sex ratio are discussed.

The acquisition of gender labels in infancy: Implications for sex-typed play

PubMed Central

Zosuls, Kristina M.; Ruble, Diane N.; Tamis-LeMonda, Catherine S.; Shrout, Patrick E.; Bornstein, Marc H.; Greulich, Faith K.

2009-01-01

Two aspects of children’s early gender development - the spontaneous production of gender labels and sex-typed play - were examined longitudinally in a sample of 82 children. Survival analysis, a statistical technique well suited to questions involving developmental transitions, was used to investigate the timing of the onset of children’s gender labeling as based on mothers’ biweekly reports on their children’s language from 9 through 21 months. Videotapes of children’s play both alone and with mother at 17 and 21 months were independently analyzed for play with gender stereotyped and neutral toys. Finally, the relation between gender labeling and sex-typed play was examined. Children transitioned to using gender labels at approximately 19 months on average. Although girls and boys showed similar patterns in the development of gender labeling, girls began labeling significantly earlier than boys. Modest sex differences in play were present at 17 months and increased at 21 months. Gender labeling predicted increases in sex-typed play, suggesting that knowledge of gender categories might influence sex-typing before the age of 2. PMID:19413425

Hybrid incompatibilities in the parasitic wasp genus Nasonia: negative effects of hemizygosity and the identification of transmission ratio distortion loci.

PubMed

Koevoets, T; Niehuis, O; van de Zande, L; Beukeboom, L W

2012-03-01

The occurrence of hybrid incompatibilities forms an important stage during the evolution of reproductive isolation. In early stages of speciation, males and females often respond differently to hybridization. Haldane's rule states that the heterogametic sex suffers more from hybridization than the homogametic sex. Although haplodiploid reproduction (haploid males, diploid females) does not involve sex chromosomes, sex-specific incompatibilities are predicted to be prevalent in haplodiploid species. Here, we evaluate the effect of sex/ploidy level on hybrid incompatibilities and locate genomic regions that cause increased mortality rates in hybrid males of the haplodiploid wasps Nasonia vitripennis and Nasonia longicornis. Our data show that diploid F(1) hybrid females suffer less from hybridization than haploid F(2) hybrid males. The latter not only suffer from an increased mortality rate, but also from behavioural and spermatogenic sterility. Genetic mapping in recombinant F(2) male hybrids revealed that the observed hybrid mortality is most likely due to a disruption of cytonuclear interactions. As these sex-specific hybrid incompatibilities follow predictions based on Haldane's rule, our data accentuate the need to broaden the view of Haldane's rule to include species with haplodiploid sex determination, consistent with Haldane's original definition.

Elevated Amygdala Perfusion Mediates Developmental Sex Differences in Trait Anxiety.

PubMed

Kaczkurkin, Antonia N; Moore, Tyler M; Ruparel, Kosha; Ciric, Rastko; Calkins, Monica E; Shinohara, Russell T; Elliott, Mark A; Hopson, Ryan; Roalf, David R; Vandekar, Simon N; Gennatas, Efstathios D; Wolf, Daniel H; Scott, J Cobb; Pine, Daniel S; Leibenluft, Ellen; Detre, John A; Foa, Edna B; Gur, Raquel E; Gur, Ruben C; Satterthwaite, Theodore D

2016-11-15

Adolescence is a critical period for emotional maturation and is a time when clinically significant symptoms of anxiety and depression increase, particularly in females. However, few studies relate developmental differences in symptoms of anxiety and depression to brain development. Cerebral blood flow is one brain phenotype that is known to have marked developmental sex differences. We investigated whether developmental sex differences in cerebral blood flow mediated sex differences in anxiety and depression symptoms by capitalizing on a large sample of 875 youths who completed cross-sectional imaging as part of the Philadelphia Neurodevelopmental Cohort. Perfusion was quantified on a voxelwise basis using arterial spin-labeled magnetic resonance imaging at 3T. Perfusion images were related to trait and state anxiety using general additive models with penalized splines, while controlling for gray matter density on a voxelwise basis. Clusters found to be related to anxiety were evaluated for interactions with age, sex, and puberty. Trait anxiety was associated with elevated perfusion in a network of regions including the amygdala, anterior insula, and fusiform cortex, even after accounting for prescan state anxiety. Notably, these relationships strengthened with age and the transition through puberty. Moreover, higher trait anxiety in postpubertal females was mediated by elevated perfusion of the left amygdala. Taken together, these results demonstrate that differences in the evolution of cerebral perfusion during adolescence may be a critical element of the affective neurobiological characteristics underlying sex differences in anxiety and mood symptoms. Copyright © 2016 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Sex differences in knee joint loading: Cross-sectional study in geriatric population.

PubMed

Ro, Du Hyun; Lee, Dong Yeon; Moon, Giho; Lee, Sahnghoon; Seo, Sang Gyo; Kim, Seong Hwan; Park, In Woong; Lee, Myung Chul

2017-06-01

This study investigated sex differences in knee biomechanics and investigated determinants for difference in a geriatric population. Age-matched healthy volunteers (42 males and 42 females, average age 65 years) without knee OA were included in the study. Subjects underwent physical examination on their knee and standing full-limb radiography for anthropometric measurements. Linear, kinetic, and kinematic parameters were compared using a three-dimensional, 12-camera motion capture system. Gait parameters were evaluated and determinants for sex difference were evaluated with multiple regression analysis. Females had a higher peak knee adduction moment (KAM) during gait (p = 0.004). Females had relatively wider pelvis and narrower step width (both p < 0.001). However, coronal knee alignment was not significantly different between the sexes. Multiple regression analysis revealed that coronal alignment (b = 0.014, p < 0.001), step width (b = -0.010, p = 0.011), and pelvic width/height ratio (b = 1.703, p = 0.046) were significant determinants of peak KAM. Because coronal alignment was not different between the sexes, narrow step width and high pelvic width/height ratio of female were the main contributors to higher peak KAM in females. Sex differences in knee biomechanics were present in the geriatric population. Increased mechanical loading on the female knee, which was associated with narrow step width and wide pelvis, may play an important role in future development and progression of OA. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1283-1289, 2017. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Molecular and cellular sex differences at the intersection of stress and arousal.

PubMed

Valentino, Rita J; Reyes, Beverly; Van Bockstaele, Elisabeth; Bangasser, Debra

2012-01-01

Elucidating the mechanisms underlying sex biases in the prevalence and severity of diseases can advance our understanding of their pathophysiological basis and serve as a guide for developing treatments. A well-established sex difference in psychiatry is the higher incidence of mood and anxiety disorders in females. These disorders share stress as a potential etiological contributor and hyperarousal as a core symptom, suggesting that the distinction between sexes lies at the intersection of stress and arousal systems. This review focuses on the link between the stress axis and the brain norepinephrine arousal system as a key point at which sex differences occur and are translated to differences in the expression of mood disorders. Evidence for a circuit designed to relay emotion-related information via the limbic corticotropin-releasing factor (CRF) system to the locus coeruleus (LC)-norepinephrine arousal system is reviewed. This is followed by recent novel findings of sex differences in CRF receptor signaling and trafficking that would result in an enhanced arousal response and a compromised ability to adapt to chronic stress in females. Finally, we discuss the evidence for sex differences in LC dendritic structure that allow for an increased receipt and processing of limbic information in females compared to males. Together these complementary sets of data suggest that in females, the LC arousal system is poised to process more limbic information and to respond to some of this information in an enhanced manner compared to males. The clinical and therapeutic considerations arising from this perspective are discussed. This article is part of a Special Issue entitled 'Anxiety and Depression'. Copyright © 2011 Elsevier Ltd. All rights reserved.

Direct bandgap materials based on the thin films of SexTe100 − x nanoparticles

PubMed Central

2012-01-01

In this study, we fabricated thin films of SexTe100 − x (x = 0, 3, 6, 9, 12, and 24) nanoparticles using thermal evaporation technique. The results obtained by X-ray diffraction show that the as-synthesized nanoparticles have polycrystalline structure, but their crystallinity decreases by increasing the concentration of Se. They were found to have direct bandgap (Eg), whose value increases by increasing the Se content. These results are completely different than those obtained in the films of SexTe100 − x microstructure counterparts. Photoluminescence and Raman spectra for these films were also demonstrated. The remarkable results obtained in these nanoparticles specially their controlled direct bandgap might be useful for the development of optical disks and other semiconductor devices. PMID:22978714

Mortality trajectory analysis reveals the drivers of sex-specific epidemiology in natural wildlife–disease interactions

PubMed Central

McDonald, Jennifer L.; Smith, Graham C.; McDonald, Robbie A.; Delahay, Richard J.; Hodgson, Dave

2014-01-01

In animal populations, males are commonly more susceptible to disease-induced mortality than females. However, three competing mechanisms can cause this sex bias: weak males may simultaneously be more prone to exposure to infection and mortality; being ‘male’ may be an imperfect proxy for the underlying driver of disease-induced mortality; or males may experience increased severity of disease-induced effects compared with females. Here, we infer the drivers of sex-specific epidemiology by decomposing fixed mortality rates into mortality trajectories and comparing their parameters. We applied Bayesian survival trajectory analysis to a 22-year longitudinal study of a population of badgers (Meles meles) naturally infected with bovine tuberculosis (bTB). At the point of infection, infected male and female badgers had equal mortality risk, refuting the hypothesis that acquisition of infection occurs in males with coincidentally high mortality. Males and females exhibited similar levels of heterogeneity in mortality risk, refuting the hypothesis that maleness is only a proxy for disease susceptibility. Instead, sex differences were caused by a more rapid increase in male mortality rates following infection. Males are indeed more susceptible to bTB, probably due to immunological differences between the sexes. We recommend this mortality trajectory approach for the study of infection in animal populations. PMID:25056621

Violence as a Barrier for HIV Prevention among Female Sex Workers in Argentina

PubMed Central

Pando, María A.; Coloccini, Romina S.; Reynaga, Elena; Rodriguez Fermepin, Marcelo; Gallo Vaulet, Lucia; Kochel, Tadeusz J.; Montano, Silvia M.; Avila, María M.

2013-01-01

Background Violence against female sex workers (FSWs) has been increasingly reported as an important determinant of HIV infection risk. This study explores the frequency of different violent experiences (sexual abuse, rejection, beating and imprisonment) among FSWs in Argentina and its association with condom use and HIV and T. pallidum prevalence. Methods A convenience sample of 1255 FSWs was included in a cross-sectional study conducted between October 2006 and November 2009. Results Sexual abuse was reported by 24.1% (219/907) of women. A total of 34.7% (42/1234) reported rejection experiences, 21.9% (267/1215) reported having been beaten and 45.4% (561/1236) stated having been arrested because of their sex work activity. There was a higher frequency of inconsistent condom use with clients among FSWs who had experienced sexual abuse, rejection, and police detention. A higher frequency of HIV and T. pallidum infection was detected among FSWs who reported having been arrested by the police. Conclusion The study shows for the first time the frequency of different violent situations among FSWs in Argentina. The association between violence against sex workers, condom use and STI prevalence demonstrated here calls for measures to reduce stigma and violence against FSWs. Such violent experiences may increase vulnerability to STI through coerced unprotected sex. PMID:23342092

National Trends in Hemoglobin Concentration and Prevalence of Anemia among Chinese School-Aged Children, 1995-2010.

PubMed

Song, Yi; Wang, Hai-Jun; Dong, Bin; Wang, Zhiqiang; Ma, Jun; Agardh, Anette

2017-04-01

To assess the trend of sex disparity in hemoglobin concentration and prevalence of anemia among Chinese school-aged children from 1995 to 2010. Data were collected from 360 866 children aged 7, 9, 12, 14, and 17 years during 4 cross-sectional surveys (1995, 2000, 2005, and 2010) of the Chinese National Surveys on Students Constitution and Health. Shifts in hemoglobin concentration distributions were compared by sex. Average shifts and sex differences were calculated with quantile regression models. Logistic regression was used to estimate the prevalence odds ratio of sex for prevalence of anemia in different surveys. The mean hemoglobin concentration increased among Chinese children between 1995 and 2010, from 132.7 to 138.3 g/L in boys, and from 127.7 to 132.3 g/L in girls. The prevalence of anemia decreased from 18.8% in 1995 to 9.9% in 2010. It was higher in rural than urban children among all age groups. The prevalence odds ratios of girls versus boys for anemia increased in both urban and rural areas over time. Hemoglobin concentration and prevalence of anemia improved among Chinese school-aged children over time. Hemoglobin concentration improved faster in boys than girls and as a result the relative prevalence of anemia in girls compared with boys increased. Sex-specific preventive guidelines and public health policies for childhood anemia are needed in China. Copyright © 2017 Elsevier Inc. All rights reserved.

Sex- and gender-related prevalence, cardiovascular risk and therapeutic approach in metabolic syndrome: A review of the literature.

PubMed

Pucci, Giacomo; Alcidi, Riccardo; Tap, Lisanne; Battista, Francesca; Mattace-Raso, Francesco; Schillaci, Giuseppe

2017-06-01

Metabolic syndrome (MS), a cluster of metabolic abnormalities linked to insulin-resistance and abdominal obesity, is associated with an increased risk of Type II diabetes mellitus (DM) and cardiovascular (CV) disease. Its prevalence is high, affecting 20%-30% of the general population, and increases with age in a sex-specific manner: in fact, while below 50 years it is slightly higher in men, it reverses after 50 years. The pronounced age-related increase in the prevalence of MS in women occurs as the result of several factors, which may be classified into sex- and gender-related factors. Sex-related factors, linked to genetical and biological pathways, are mainly driven by hyperandrogenism, insulin-resistance, and the associated increase in abdominal obesity and HDL-cholesterol reduction occurring after menopause. Gender-related factors are sensitive to social and cultural behaviors, dietary habits and psychosocial factors. Women are more prone than men to develop MS in response to work stress and low socio-economic status. Sex and gender differences in the prevalence of MS may translate in different CV risk associated. Prospective studies suggest that the CV risk in women with MS is not only equal but also superior to the CV risk of men with MS. This difference is mostly attenuated when adjusting for the presence of overt DM. Despite similar odds for CV events, the number of CV events may be higher in elderly women because of the higher prevalence of MS compared to men in this age group. Men and women may also have a differential response to treatments for MS, such as lifestyle measures and weight loss. Recent observations suggest that men are better responders than women to non-pharmaceutical therapeutic strategies aimed at reducing the prevalence of MS, although this should be confirmed in large-scale studies. The present review describes the impact of sex and gender on the prevalence, clinical presentation, prognostic significance and treatment of the MS. Attention to gender specificities should be a mandatory pre-requisite of clinical and epidemiological research on MS and CV disease, for a better knowledge and development of health strategies. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Sex differences and anesthesiology: preface and comments].

PubMed

Nishno, Takashi

2009-01-01

In this special issue, the topic of sex difference in the field of anesthesiology is featured. Eight subtopics are discussed including 1) sex differences in cardiovascular medicine, 2) perioperative cardiovascular management, 3) sex differences in the respiratory functions of the upper airway, 4) sex differences in the anesthetic management, 5) sex differences in pain, 6) sex differences in laboratory medicine, 7) sex differences in pharmacokinetics of anesthetics, and 8) postoperative nausea and vomiting. Although recent clinical and experimental studies have shown the existence of sex and/or gender differences in many fields of medicine, our knowledge of sex differences in anesthesiology is apparently insufficient. I believe that anesthesiologists should pay more attention to this topic to improve our daily practice of anesthesia.

Sex-Dependent Effects of Cannabis and Cannabinoids: A Translational Perspective.

PubMed

Cooper, Ziva D; Craft, Rebecca M

2018-01-01

Recent policy changes have led to significant increases in the use of cannabis for both medical and recreational purposes. Although men are more likely to endorse past month cannabis use and are more frequently diagnosed with Cannabis Use Disorder relative to women, a growing proportion of medical cannabis users are reported to be women. The increased popularity of cannabis for medical purposes and the narrowing gap in prevalence of use between men and women raises questions regarding sex-dependent effects related to therapeutic efficacy and negative health effects of cannabis and cannabinoids. The objective of this review is to provide a translational perspective on the sex-dependent effects of cannabis and cannabinoids by synthesizing findings from preclinical and clinical studies focused on sex comparisons of their therapeutic potential and abuse liability, two specific areas that are of significant public health relevance. Hormonal and pharmacological mechanisms that may underlie sex differences in the effects of cannabis and cannabinoids are highlighted.

Sex differences and structural brain maturation from childhood to early adulthood.

PubMed

Koolschijn, P Cédric M P; Crone, Eveline A

2013-07-01

Recent advances in structural brain imaging have demonstrated that brain development continues through childhood and adolescence. In the present cross-sectional study, structural MRI data from 442 typically developing individuals (range 8-30) were analyzed to examine and replicate the relationship between age, sex, brain volumes, cortical thickness and surface area. Our findings show differential patterns for subcortical and cortical areas. Analysis of subcortical volumes showed that putamen volume decreased with age and thalamus volume increased with age. Independent of age, males demonstrated larger amygdala and thalamus volumes compared to females. Cerebral white matter increased linearly with age, at a faster pace for females than males. Gray matter showed nonlinear decreases with age. Sex-by-age interactions were primarily found in lobar surface area measurements, with males demonstrating a larger cortical surface up to age 15, while cortical surface in females remained relatively stable with increasing age. The current findings replicate some, but not all prior reports on structural brain development, which calls for more studies with large samples, replications, and specific tests for brain structural changes. In addition, the results point toward an important role for sex differences in brain development, specifically during the heterogeneous developmental phase of puberty. Copyright © 2013 Elsevier Ltd. All rights reserved.

Cognitive ability influences on written expression: Evidence for developmental and sex-based differences in school-age children.

PubMed

Hajovsky, Daniel B; Villeneuve, Ethan F; Reynolds, Matthew R; Niileksela, Christopher R; Mason, Benjamin A; Shudak, Nicholas J

2018-04-01

Some studies have demonstrated that the Cattell-Horn-Carroll (CHC) cognitive abilities influence writing; however, little research has investigated whether CHC cognitive abilities influence writing the same way for males and females across grades. We used multiple group structural equation models to investigate whether CHC cognitive ability influences on written expression differed between grades or sex using the Kaufman Assessment Battery for Children, Second Edition and the Kaufman Tests of Educational Achievement, Second Edition co-normed standardization sample data (N=2117). After testing for consistent measurement of cognitive abilities across grades and sex, we tested whether the cognitive ability influences on written expression were moderated by grade level or sex. An important developmental shift was observed equally across sex groups: Learning Efficiency (Gl) influences decreased whereas Crystallized Ability (Gc) influences increased after fourth grade. Further, Short-Term Memory (Gsm) and Retrieval Fluency (Gr) influences on written expression depended on sex at grades 1-4, with larger Gr influences for females and larger Gsm influences for males. We internally replicated our main findings using two different cognitive explanatory models, adding further support for the developmental and sex-based differential cognitive ability influences on writing. Explanatory cognitive models of writing need to incorporate development, and possibly, sex to provide an expanded understanding of writing development and guard against potential generalizability issues characteristic of special population (i.e., male-female) studies. Copyright © 2017 Society for the Study of School Psychology. Published by Elsevier Ltd. All rights reserved.

Differences in sexual guilt and desire in east Asian and Euro-Canadian men.

PubMed

Brotto, Lori A; Woo, Jane S T; Gorzalka, Boris B

2012-01-01

Differences in sexual desire between individuals of East Asian and European descent are well-documented, with East Asian individuals reporting lower sexual desire. The mechanisms that underlie this disparity have received little empirical attention. Recent research has found that sex guilt, "a generalized expectancy for self-mediated punishment for violating or for anticipating violating standards of proper sexual conduct" (Mosher & Cross, 1971 , p. 27), mediates the relationship between culture and sexual desire in East Asian and Euro-Canadian women. The goal of this study was to explore this role of sex guilt in men. Male Euro-Canadian (n = 38) and East Asian (n = 45) university students completed online questionnaires. The East Asian men reported significantly lower sexual desire and significantly higher sex guilt. Sex guilt was a significant mediator of the relationship between ethnicity and sexual desire, as well as a significant mediator between mainstream acculturation and sexual desire. Among the East Asian men, mainstream acculturation was significantly and negatively correlated with sex guilt such that increasing mainstream acculturation was associated with less sex guilt. The diagnostic and clinical implications of the findings are discussed.

Right ventricular sex differences in patients with idiopathic pulmonary arterial hypertension characterised by magnetic resonance imaging: pair-matched case controlled study.

PubMed

Swift, Andrew J; Capener, Dave; Hammerton, Charlotte; Thomas, Steven M; Elliot, Charlie; Condliffe, Robin; Wild, Jim M; Kiely, David G

2015-01-01

Sex differences exist in both the prevalence and survival of patients with idiopathic pulmonary arterial hypertension (IPAH). Men are less frequently affected by the condition but have worse outcome as compared to females. We sought to characterise the sex related differences in right ventricular remodelling in age matched male and female patients with IPAH using cardiac magnetic resonance imaging (MRI). A case controlled pair-matched study was conducted with patients matched by age and sex. Steady state free precession (SSFP) MRI of the heart was performed at 1.5T. Cardiac volume, function and mass measurements were corrected for age, sex and BSA according to reference data. 40 age and sex matched patients with IPAH were identified. The mean age was 57 (SD 17) in both male and female cohorts. Men had proportionally lower right ventricular (RV) ejection fraction, RV stroke volume and LV stroke volume than females, p=0.028, p=0.007 and p=0.013, respectively. However, there was no significant difference in RV mass or haemodynamic indices of mPAP and PVR between males and females. Male patients with IPAH have proportionally worse RV function despite similar afterload. We hypothesise that adaptive remodelling of the RV in response to increased afterload in IPAH is more effective in females.

Right Ventricular Sex Differences in Patients with Idiopathic Pulmonary Arterial Hypertension Characterised by Magnetic Resonance Imaging: Pair-Matched Case Controlled Study

PubMed Central

Swift, Andrew J.; Capener, Dave; Hammerton, Charlotte; Thomas, Steven M.; Elliot, Charlie; Condliffe, Robin; Wild, Jim M.; Kiely, David G.

2015-01-01

Purpose Sex differences exist in both the prevalence and survival of patients with idiopathic pulmonary arterial hypertension (IPAH). Men are less frequently affected by the condition but have worse outcome as compared to females. We sought to characterise the sex related differences in right ventricular remodelling in age matched male and female patients with IPAH using cardiac magnetic resonance imaging (MRI). Methods A case controlled pair-matched study was conducted with patients matched by age and sex. Steady state free precession (SSFP) MRI of the heart was performed at 1.5T. Cardiac volume, function and mass measurements were corrected for age, sex and BSA according to reference data. Results 40 age and sex matched patients with IPAH were identified. The mean age was 57 (SD 17) in both male and female cohorts. Men had proportionally lower right ventricular (RV) ejection fraction, RV stroke volume and LV stroke volume than females, p=0.028, p=0.007 and p=0.013, respectively. However, there was no significant difference in RV mass or haemodynamic indices of mPAP and PVR between males and females. Conclusion Male patients with IPAH have proportionally worse RV function despite similar afterload. We hypothesise that adaptive remodelling of the RV in response to increased afterload in IPAH is more effective in females. PMID:25996939

X chromosome dosage and presence of SRY shape sex-specific differences in DNA methylation at an autosomal region in human cells.

PubMed

Ho, Bianca; Greenlaw, Keelin; Al Tuwaijri, Abeer; Moussette, Sanny; Martínez, Francisco; Giorgio, Elisa; Brusco, Alfredo; Ferrero, Giovanni Battista; Linhares, Natália D; Valadares, Eugênia R; Svartman, Marta; Kalscheuer, Vera M; Rodríguez Criado, Germán; Laprise, Catherine; Greenwood, Celia M T; Naumova, Anna K

2018-02-20

Sexual dimorphism in DNA methylation levels is a recurrent epigenetic feature in different human cell types and has been implicated in predisposition to disease, such as psychiatric and autoimmune disorders. To elucidate the genetic origins of sex-specific DNA methylation, we examined DNA methylation levels in fibroblast cell lines and blood cells from individuals with different combinations of sex chromosome complements and sex phenotypes focusing on a single autosomal region--the differentially methylated region (DMR) in the promoter of the zona pellucida binding protein 2 (ZPBP2) as a reporter. Our data show that the presence of the sex determining region Y (SRY) was associated with lower methylation levels, whereas higher X chromosome dosage in the absence of SRY led to an increase in DNA methylation levels at the ZPBP2 DMR. We mapped the X-linked modifier of DNA methylation to the long arm of chromosome X (Xq13-q21) and tested the impact of mutations in the ATRX and RLIM genes, located in this region, on methylation levels. Neither ATRX nor RLIM mutations influenced ZPBP2 methylation in female carriers. We conclude that sex-specific methylation differences at the autosomal locus result from interaction between a Y-linked factor SRY and at least one X-linked factor that acts in a dose-dependent manner.

Sex Differences in the Neural Correlates of Specific and General Autobiographical Memory

PubMed Central

Compère, Laurie; Sperduti, Marco; Gallarda, Thierry; Anssens, Adèle; Lion, Stéphanie; Delhommeau, Marion; Martinelli, Pénélope; Devauchelle, Anne-Dominique; Oppenheim, Catherine; Piolino, Pascale

2016-01-01

Autobiographical memory (AM) underlies the formation and temporal continuity over time of personal identity. The few studies on sex-related differences in AM suggest that men and women adopt different cognitive or emotional strategies when retrieving AMs. However, none of the previous works has taken into account the distinction between episodic autobiographical memory (EAM), consisting in the retrieval of specific events by means of mental time travel, and semantic autobiographical memory (SAM), which stores general personal events. Thus, it remains unclear whether differences in these strategies depend on the nature of the memory content to be retrieved. In the present study we employed functional MRI to examine brain activity underlying potential sex differences in EAM and SAM retrieval focusing on the differences in strategies related to the emotional aspects of memories while controlling for basic cognitive strategies. On the behavioral level, there was no significant sex difference in memory performances or subjective feature ratings of either type of AM. Activations common to men and women during AM retrieval were observed in a typical bilateral network comprising medial and lateral temporal regions, precuneus, occipital cortex as well as prefrontal cortex. Contrast analyses revealed that there was no difference between men and women in the EAM condition. In the SAM condition, women showed an increased activity, compared to men, in the dorsal anterior cingulate cortex, inferior parietal and precentral gyrus. Overall, these findings suggest that differential neural activations reflect sex-specific strategies related to emotional aspects of AMs, particularly regarding SAM. We propose that this pattern of activation during SAM retrieval reflects the cognitive cost linked to emotion regulation strategies recruited by women compared to men. These sex-related differences have interesting implications for understanding psychiatric disorders with differential sex prevalence and in which one of key features is overgenerality in AM. PMID:27378884

Sexual dimorphism in BDNF signaling after neonatal hypoxia-ischemia and treatment with necrostatin-1

PubMed Central

Chavez-Valdez, Raul; Martin, Lee J.; Razdan, Sheila; Gauda, Estelle B.; Northington, Frances J.

2014-01-01

Brain injury due to neonatal hypoxia-ischemia (HI) is more homogenously severe in male than in female mice. Because, necrostatin-1 (nec-1) prevents injury progression only in male mice, we hypothesized that changes in BDNF signaling after HI and nec-1 are also sex-specific providing differential conditions to promote recovery of those more severely injured. The increased aromatization of testosterone in male mice during early development and the link between 17-β-estradiol (E2) levels and BDNF transcription substantiate this hypothesis. Hence, we aimed to investigate if sexual differences in BDNF signaling existed in forebrain and diencephalon after HI and HI/ nec-1 and their correlation with estrogen receptors (ER). C57B6 mice (p7) received nec-1(0.1 μL[8μM]) or vehicle (veh) intracerebroventricularly after HI. At 24h after HI, BDNF levels increased in both sexes in forebrain without evidence of TrkB activation. At 96h after HI, BDNF levels in forebrain decreased below those seen in control mice of both sexes. Additionally, only in female mice, truncated TrkB (Tc.TrkB) and p75ntr levels increased in forebrain and diencephalon. In both, forebrain and diencephalon, nec-1 treatment increased BDNF levels and TrkB activation in male mice while, prevented Tc.TrkB and p75ntr increases in female mice. While E2 levels were unchanged by HI or HI/ nec-1 in either sex or treatment, ERα: ERβ ratios were increased in diencephalon of nec-1 treated male mice and directly correlated with BDNF levels. Neonatal HI produces sex-specific signaling changes in the BDNF system, that are differentially modulated by nec-1. The regional differences in BDNF levels may be a consequence of injury severity after HI, but sexual differences in response to nec-1 after HI may represent a differential thalamo-cortical preservation or alternatively off-target regional effect of nec-1. The biological significance of ERα predominance and its correlation with BDNF levels is still unclear. PMID:24361177

Increasing sex differences in the use of cardiac resynchronization therapy with or without implantable cardioverter-defibrillator

PubMed Central

Chatterjee, Neal A.; Borgquist, Rasmus; Chang, Yuchiao; Lewey, Jennifer; Jackson, Vicki A.; Singh, Jagmeet P.; Metlay, Joshua P.; Lindvall, Charlotta

2017-01-01

Aims Previous studies have identified sex disparities in the use of cardiac resynchronization therapy (CRT) and implantable cardioverter defibrillators (ICD), although the basis of underutilization in women remains poorly understood. The aim of this study was to assess sex differences in patterns of CRT use with our without ICD. Methods and results In this cross-sectional study using the National Inpatient Sample database we identified 311 009 patients undergoing CRT implantation in the United States between 2006 and 2012. Demographic and clinical characteristics were compared between men and women undergoing CRT implantation, with special attention to clinical predictors of left ventricular reverse remodelling (CRT response, score range: 0–4) and reduced ICD efficacy (score range: 0–7). When compared to men, women undergoing CRT implantation were significantly more likely to have ≥ 3 predictors of CRT response (47.3 vs. 33.2%, P < 0.001) and less likely to have ≥3 predictors of reduced ICD efficacy (27.0 vs. 37.3%, P < 0.001). Despite this, men were significantly more likely to undergo CRT with ICD (CRT-D) as the type of CRT (88.6 vs. 80.1% of all CRT implants). Compared to those with the greatest likelihood of CRT response (score ≥ 3), those with the least likelihood of CRT response had a significant decreased odds of CRT-D implant (adj odds ratio 0.27 [0.24–0.31], P < 0.001), with a greater decreased odds in women compared to men (P, for sex interaction <0.001). The difference in the % of CRT-D implant in men vs. women increased over the study period (P, sex Δ time trend = 0.012). Conclusion In this large, contemporary cohort, sex differences in CRT-D implantation were inversely related to predicted CRT efficacy and have increased over time. Future efforts to narrow the gap in CRT-D implantation in men and women may help better align device selection with those most likely to benefit. PMID:28065904

Sex ratios in fetuses and liveborn infants with autosomal aneuploidy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Heuther, C.A.; Martin, R.L.M.; Stoppelman, S.M.

1996-06-14

Ten data sources were used substantially to increase the available data for estimating fetal and livebirth sex ratios for Patau (trisomy 13), Edwards (trisomy 18), and Down (trisomy 21) syndromes and controls. The fetal sex ratio estimate was 0.88 (N = 584) for trisomy 13, 0.90 (N = 1702) for trisomy 18, and 1.16 (N = 3154) for trisomy 21. All were significantly different from prenatal controls (1.07). The estimated ratios in prenatal controls were 1.28 (N = 1409) for CVSs and 1.06 (N = 49427) for amniocenteses, indicating a clear differential selection against males, mostly during the first halfmore » of fetal development. By contrast, there were no sex ratio differences for any of the trisomies when comparing gestational ages <16 and >16 weeks. The livebirth sex ratio estimate was 0.90 (N = 293) for trisomy 13, 0.63 (N = 497) for trisomy 18, and 1.15 (N = 6424) for trisomy 21, the latter two being statistically different than controls (1.05) (N = 3660707). These ratios for trisomies 13 and 18 were also statistically different than the ratio for trisomy 21. Only in trisomy 18 did the sex ratios in fetuses and livebirths differ, indicating a prenatal selection against males >16 weeks. No effects of maternal age or race were found on these estimates for any of the fetal or livebirth trisomies. Sex ratios for translocations and mosaics were also estimated for these aneuploids. Compared to previous estimates, these results are less extreme, most likely because of larger sample sizes and less sample bias. They support the hypothesis that these trisomy sex ratios are skewed at conception, or become so during embryonic development through differential intrauterine selection. The estimate for Down syndrome livebirths is also consistent with the hypothesis that its higher sex ratio is associated with paternal nondisjunction. 36 refs., 5 tabs.« less

Associations between biological markers of prenatal stress and infant negative emotionality are specific to sex.

PubMed

Braithwaite, Elizabeth C; Murphy, Susannah E; Ramchandani, Paul G; Hill, Jonathan

2017-12-01

Fetal programming is the idea that environmental stimuli can alter the development of the fetus, which may have a long-term effect on the child. We have recently reported that maternal prenatal cortisol predicts infant negative emotionality in a sex-dependent manner: high prenatal cortisol was associated with increased negative emotionality in females, and decreased negative emotionality in males. This study aims to test for this sex-specific effect in a different cohort, and investigate whether sex differences in fetal programming may be specific to glucocorticoid mechanisms by also examining a maternal salivary alpha-amylase (sAA) by sex interaction. 88 pregnant women (mean gestational age=27.4 weeks, SD=7.4) collected saliva samples at home over two working days to be assayed for the hormone cortisol (range=0.13-88.22nmol/l) and the enzyme alpha-amylase (range=4.57-554.8units/ml). Samples were collected at waking, 30-min post-waking and 12h post-waking. Two months after birth participants reported infant negative emotionality using the distress to limits subscale of the Infant Behavior Questionnaire. The interaction between maternal prenatal cortisol and infant sex to predict distress to limits approached significance (p=0.067). In line with our previous finding there was a positive association between prenatal cortisol and negative emotionality in females, and a negative association in males. The interaction between sAA and sex to predict distress was significant (p=0.025), and the direction of effect was the same as for the cortisol data; high sAA associated with increased negative emotionality in females and reduced negative emotionality in males. In line with our previous findings, this research adds to an emerging body of literature, which suggests that fetal programming mechanisms may be sex-dependent. This is the first study to demonstrate that maternal prenatal sAA may be an important biomarker for infant behavior, and the findings have implications for understanding sex differences in developmental psychopathology. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Differences in the Thoracic Aorta by Region and Sex in a Murine Model of Marfan Syndrome.

PubMed

Jiménez-Altayó, Francesc; Siegert, Anna-Maria; Bonorino, Fabio; Meirelles, Thayna; Barberà, Laura; Dantas, Ana P; Vila, Elisabet; Egea, Gustavo

2017-01-01

Marfan syndrome (MFS) is a hereditary disorder of the connective tissue that causes life-threatening aortic aneurysm, which initiates at the aortic root and can progress into the ascending portion. However, analysis of ascending aorta reactivity in animal models of MFS has remained elusive. Epidemiologic evidence suggests that although MFS is equally prevalent in men and women, men are at a higher risk of aortic complications than non-pregnant women. Nevertheless, there is no experimental evidence to support this hypothesis. The aim of this study was to explore whether there are regional and sex differences in the thoracic aorta function of mice heterozygous for the fibrillin 1 ( Fbn1 ) allele encoding a missense mutation ( Fbn1 C1039G/+ ), the most common class of mutation in MFS. Ascending and descending thoracic aorta reactivity was evaluated by wire myography. Ascending aorta mRNA and protein levels, and elastic fiber integrity were assessed by qRT-PCR, Western blotting, and Verhoeff-Van Gieson histological staining, respectively. MFS differently altered reactivity in the ascending and descending thoracic aorta by either increasing or decreasing phenylephrine contractions, respectively. When mice were separated by sex, contractions to phenylephrine increased progressively from 3 to 6 months of age in MFS ascending aortas of males, whereas contractions in females were unchanged. Endothelium-dependent relaxation was unaltered in the MFS ascending aorta of either sex; an effect related to augmented endothelium-dependent hyperpolarization-type dilations. In MFS males, the non-selective cyclooxygenase (COX) inhibitor indomethacin prevented the MFS-induced enhancement of phenylephrine contractions linked to increased COX-2 expression. In MFS mice of both sexes, the non-selective nitric oxide synthase inhibitor L-NAME revealed negative feedback of nitric oxide on phenylephrine contractions, which was associated with upregulation of eNOS in females. Finally, MFS ascending aortas showed a greater number of elastic fiber breaks than the wild-types, and males exhibited more breaks than females. These results show regional and sex differences in Fbn1 C1039G/+ mice thoracic aorta contractility and aortic media injuries. The presence of more pronounced aortic alterations in male mice provides experimental evidence to support that male MFS patients are at increased risk of suffering aortic complications.

Differences in the Thoracic Aorta by Region and Sex in a Murine Model of Marfan Syndrome

PubMed Central

Jiménez-Altayó, Francesc; Siegert, Anna-Maria; Bonorino, Fabio; Meirelles, Thayna; Barberà, Laura; Dantas, Ana P.; Vila, Elisabet; Egea, Gustavo

2017-01-01

Marfan syndrome (MFS) is a hereditary disorder of the connective tissue that causes life-threatening aortic aneurysm, which initiates at the aortic root and can progress into the ascending portion. However, analysis of ascending aorta reactivity in animal models of MFS has remained elusive. Epidemiologic evidence suggests that although MFS is equally prevalent in men and women, men are at a higher risk of aortic complications than non-pregnant women. Nevertheless, there is no experimental evidence to support this hypothesis. The aim of this study was to explore whether there are regional and sex differences in the thoracic aorta function of mice heterozygous for the fibrillin 1 (Fbn1) allele encoding a missense mutation (Fbn1C1039G/+), the most common class of mutation in MFS. Ascending and descending thoracic aorta reactivity was evaluated by wire myography. Ascending aorta mRNA and protein levels, and elastic fiber integrity were assessed by qRT-PCR, Western blotting, and Verhoeff-Van Gieson histological staining, respectively. MFS differently altered reactivity in the ascending and descending thoracic aorta by either increasing or decreasing phenylephrine contractions, respectively. When mice were separated by sex, contractions to phenylephrine increased progressively from 3 to 6 months of age in MFS ascending aortas of males, whereas contractions in females were unchanged. Endothelium-dependent relaxation was unaltered in the MFS ascending aorta of either sex; an effect related to augmented endothelium-dependent hyperpolarization-type dilations. In MFS males, the non-selective cyclooxygenase (COX) inhibitor indomethacin prevented the MFS-induced enhancement of phenylephrine contractions linked to increased COX-2 expression. In MFS mice of both sexes, the non-selective nitric oxide synthase inhibitor L-NAME revealed negative feedback of nitric oxide on phenylephrine contractions, which was associated with upregulation of eNOS in females. Finally, MFS ascending aortas showed a greater number of elastic fiber breaks than the wild-types, and males exhibited more breaks than females. These results show regional and sex differences in Fbn1C1039G/+ mice thoracic aorta contractility and aortic media injuries. The presence of more pronounced aortic alterations in male mice provides experimental evidence to support that male MFS patients are at increased risk of suffering aortic complications. PMID:29187826

Temperature-dependent sex determination modulates cardiovascular maturation in embryonic snapping turtles Chelydra serpentina.

PubMed

Alvine, Travis; Rhen, Turk; Crossley, Dane A

2013-03-01

We investigated sex differences in cardiovascular maturation in embryos of the snapping turtle Chelydra serpentina, a species with temperature-dependent sex determination. One group of eggs was incubated at 26.5°C to produce males. Another group of eggs was incubated at 26.5°C until embryos reached stage 17; eggs were then shifted to 31°C for 6 days to produce females, and returned to 26.5°C for the rest of embryogenesis. Thus, males and females were at the same temperature when autonomic tone was determined and for most of development. Cholinergic blockade increased resting blood pressure (P(m)) and heart rate (f(H)) in both sexes at 75% and 90% of incubation. However, the magnitude of the f(H) response was enhanced in males compared with females at 90% of incubation. β-adrenergic blockade increased P(m) at 75% of incubation in both sexes but had no effect at 90% of incubation. β-adrenergic blockade reduced f(H) at both time points but produced a stronger response at 90% versus 75% of incubation. We found that α-adrenergic blockade decreased P(m) in both sexes at 75% and 90% of incubation and decreased f(H) at 75% of incubation in both sexes. At 90% of incubation, f(H) decreased in females but not males. Although these data clearly demonstrate sexual dimorphism in the autonomic regulation of cardiovascular physiology in embryos, further studies are needed to test whether differences are caused by endocrine signals from gonads or by a hormone-independent temperature effect.

Friendship Selection and Influence Processes for Physical Aggression and Prosociality: Differences between Single-Sex and Mixed-Sex Contexts.

PubMed

Dijkstra, Jan Kornelis; Berger, Christian

2018-01-01

The present study examined to what extent selection and influence processes for physical aggression and prosociality in friendship networks differed between sex-specific contexts (i.e., all-male, all-female, and mixed-sex classrooms), while controlling for perceived popularity. Whereas selection processes reflect how behaviors shape friendships, influence processes reveal the reversed pattern by indicating how friends affect individual behaviors. Data were derived from a longitudinal sample of early adolescents from Chile. Four all-male classrooms ( n  = 150 male adolescents), four all-female classrooms ( n  = 190 female adolescents), and eight mixed-sex classrooms ( n  = 272 students) were followed one year from grades 5 to 6 ( M age  = 13). Analyses were conducted by means of stochastic-actor-based modeling as implemented in RSIENA. Although it was expected that selection and influence effects for physical aggression and prosociality would vary by context, these effects showed remarkably similar trends across all-male, all-female, and mixed-sex classrooms, with physical aggression reducing and with prosociality increasing the number of nominations received as best friend in all-male and particularly all-female classrooms. Further, perceived popularity increased the number of friendship nominations received in all contexts. Influence processes were only found for perceived popularity, but not for physical aggression and prosociality in any of the three contexts. Together, these findings highlight the importance of both behaviors for friendship selection independent of sex-specific contexts, attenuating the implications of these gendered behaviors for peer relations.

Condom negotiation across different relationship types by young women engaged in sex work in Phnom Penh, Cambodia

PubMed Central

Maher, Lisa; Mooney-Somers, Julie; Phlong, Pisith; Couture, Marie-Claude; Kien, Serey Phal; Stein, Ellen; Bates, Anna Juong; Sansothy, Neth; Page, Kimberly

2013-01-01

Cambodia's 100% Condom Use Programme is credited with an increase in consistent condom use in commercial sexual interactions and a decrease in HIV prevalence among female sex workers (FSWs). There has been little improvement in condom use between FSWs and non-commercial partners, prompting calls for more innovative approaches to increasing condom use in these relationships. To understand why condoms are used or not used in sexual interactions involving FSWs, we examined condom negotiation across different types of relationships. We conducted 33 in-depth interviews with young (15 to 29 years) women engaged in sex work in Phnom Penh. There was an important interplay between the meanings of condom use and the meanings of women's relationships. Commercial relationships were characterised as inherently risky and necessitated condom use. Despite a similar lack of sexual fidelity, sweetheart relationships were rarely construed as risky and typically did not involve condom use. Husbands and wives constructed their sexual interactions with each other differently, making agreement on condom use difficult. The lack of improvement in condom use in FSWs' non-commercial sexual relationships needs to be understood in relation to both sex work and the broader Cambodian sexual culture within which these relationships are embedded. PMID:23432108

Sex-specific effects of a parasite evolving in a female-biased host population

PubMed Central

2012-01-01

Background Males and females differ in many ways and might present different opportunities and challenges to their parasites. In the same way that parasites adapt to the most common host type, they may adapt to the characteristics of the host sex they encounter most often. To explore this hypothesis, we characterized host sex-specific effects of the parasite Pasteuria ramosa, a bacterium evolving in naturally, strongly, female-biased populations of its host Daphnia magna. Results We show that the parasite proliferates more successfully in female hosts than in male hosts, even though males and females are genetically identical. In addition, when exposure occurred when hosts expressed a sexual dimorphism, females were more infected. In both host sexes, the parasite causes a similar reduction in longevity and leads to some level of castration. However, only in females does parasite-induced castration result in the gigantism that increases the carrying capacity for the proliferating parasite. Conclusions We show that mature male and female Daphnia represent different environments and reveal one parasite-induced symptom (host castration), which leads to increased carrying capacity for parasite proliferation in female but not male hosts. We propose that parasite induced host castration is a property of parasites that evolved as an adaptation to specifically exploit female hosts. PMID:23249484

Sex-specific effects of a parasite evolving in a female-biased host population.

PubMed

Duneau, David; Luijckx, Pepijn; Ruder, Ludwig F; Ebert, Dieter

2012-12-18

Males and females differ in many ways and might present different opportunities and challenges to their parasites. In the same way that parasites adapt to the most common host type, they may adapt to the characteristics of the host sex they encounter most often. To explore this hypothesis, we characterized host sex-specific effects of the parasite Pasteuria ramosa, a bacterium evolving in naturally, strongly, female-biased populations of its host Daphnia magna. We show that the parasite proliferates more successfully in female hosts than in male hosts, even though males and females are genetically identical. In addition, when exposure occurred when hosts expressed a sexual dimorphism, females were more infected. In both host sexes, the parasite causes a similar reduction in longevity and leads to some level of castration. However, only in females does parasite-induced castration result in the gigantism that increases the carrying capacity for the proliferating parasite. We show that mature male and female Daphnia represent different environments and reveal one parasite-induced symptom (host castration), which leads to increased carrying capacity for parasite proliferation in female but not male hosts. We propose that parasite induced host castration is a property of parasites that evolved as an adaptation to specifically exploit female hosts.

'In different situations, in different ways': male sex work in St. Petersburg, Russia.

PubMed

Niccolai, Linda M; King, Elizabeth J; Eritsyan, Ksenia U; Safiullina, Liliya; Rusakova, Maia M

2013-01-01

We conducted a qualitative study of male sex work in St. Petersburg Russia with a focus on social vulnerabilities, HIV-risk perception and HIV-related behaviours. In-depth interviews were conducted with individuals knowledgeable about male sex work through their profession and with male sex workers themselves. Male sex work involves a variety of exchanges, including expensive vacations, negotiated monetary amounts or simply access to food. Methods of finding clients included the Internet, social venues (e.g. gay clubs and bars) and public places (e.g. parks). Use of the Internet greatly facilitated male sex work in a variety of ways. It was used by both individuals and agencies to find clients, and appeared to be increasing. Men often reported not being professionally connected to other male sex workers and limited disclosure about their work. Many were aware of the work-related risks to personal safety, including violence and robbery by clients. Perceived risk for HIV was mostly abstract and several exceptions to condom use with clients were noted. Alcohol use was reported as moderate but alcohol was consumed frequently in association with work. These data suggest that the most salient risks for male sex workers include professional isolation, threats to personal safety, limited perceived HIV risk and sub-optimal levels of condom use.

Cerebrovascular regulation in men and women: stimulus-specific role of cyclooxygenase

PubMed Central

Peltonen, Garrett L; Harrell, John W; Rousseau, Cameron L; Ernst, Brady S; Marino, Mariah L; Crain, Meghan K; Schrage, William G

2015-01-01

Greater cerebral artery vasodilation mediated by cyclooxygenase (COX) in female animals is unexplored in humans. We hypothesized that young, healthy women would exhibit greater basal cerebral blood flow (CBF) and greater vasodilation during hypoxia or hypercapnia compared to men, mediated by a larger contribution of COX. We measured middle cerebral artery velocity (MCAv, transcranial Doppler ultrasound) in 42 adults (24 women, 18 men; 24 ± 1 years) during two visits, in a double-blind, placebo-controlled design (COX inhibition, 100 mg oral indomethacin, Indo). Women were studied early in the follicular phase of the menstrual cycle (days 1–5). Two levels of isocapnic hypoxia (SPO2 = 90% and 80%) were induced for 5-min each. Separately, hypercapnia was induced by increasing end-tidal carbon dioxide (PETCO2) 10 mmHg above baseline. A positive change in MCAv (ΔMCAv) reflected vasodilation. Basal MCAv was greater in women compared to men (P < 0.01) across all conditions. Indo decreased baseline MCAv (P < 0.01) similarly between sexes. Hypoxia increased MCAv (P < 0.01), but ΔMCAv was not different between sexes. Indo did not alter hypoxic vasodilation in either sex. Hypercapnia increased MCAv (P < 0.01), but ΔMCAv was not different between sexes. Indo elicited a large decrease in hypercapnic vasodilation (P < 0.01) that was similar between sexes. During the early follicular phase, women exhibit greater basal CBF than men, but similar vasodilatory responses to hypoxia and hypercapnia. Moreover, COX is not obligatory for hypoxic vasodilation, but plays a vital and similar role in the regulation of basal CBF (∼30%) and hypercapnic response (∼55%) between sexes. PMID:26149282

Sex differences in the pro-inflammatory cytokine response to endotoxin unfold in vivo but not ex vivo in healthy humans.

PubMed

Wegner, Alexander; Benson, Sven; Rebernik, Laura; Spreitzer, Ingo; Jäger, Marcus; Schedlowski, Manfred; Elsenbruch, Sigrid; Engler, Harald

2017-07-01

Clinical data indicate that inflammatory responses differ across sexes, but the mechanisms remain elusive. Herein, we assessed in vivo and ex vivo cytokine responses to bacterial endotoxin in healthy men and women to elucidate the role of systemic and cellular factors underlying sex differences in inflammatory responses. Participants received an i.v. injection of low-dose endotoxin (0.4 ng/kg body mass), and plasma TNF-α and IL-6 responses were analyzed over a period of 6 h. In parallel, ex vivo cytokine production was measured in endotoxin-stimulated blood samples obtained immediately before in vivo endotoxin administration. As glucocorticoids (GCs) play an important role in the negative feedback regulation of the inflammatory response, we additionally analyzed plasma cortisol concentrations and ex vivo GC sensitivity of cytokine production. Results revealed greater in vivo pro-inflammatory responses in women compared with men, with significantly higher increases in plasma TNF-α and IL-6 concentrations. In addition, the endotoxin-induced rise in plasma cortisol was more pronounced in women. In contrast, no sex differences in ex vivo cytokine production and GC sensitivity were observed. Together, these findings demonstrate major differences in in vivo and ex vivo responses to endotoxin and underscore the importance of systemic factors underlying sex differences in the inflammatory response.

Complementarity of sex differences in brain and behavior: From laterality to multimodal neuroimaging.

PubMed

Gur, Ruben C; Gur, Raquel E

2017-01-02

Although, overwhelmingly, behavior is similar in males and females, and, correspondingly, the brains are similar, sex differences permeate both brain and behavioral measures, and these differences have been the focus of increasing scrutiny by neuroscientists. This Review describes milestones from more than 3 decades of research in brain and behavior. This research was necessarily bound by available methodology, and we began with indirect behavioral indicators of brain function such as handedness. We proceeded to the use of neuropsychological batteries and then to structural and functional neuroimaging that provided the foundations of a cognitive neuroscience-based computerized neurocognitive battery. Sex differences were apparent and consistent in neurocognitive measures, with females performing better on memory and social cognition tasks and males on spatial processing and motor speed. Sex differences were also prominent in all major brain parameters, including higher rates of cerebral blood flow, higher percentage of gray matter tissue, and higher interhemispheric connectivity in females, compared with higher percentage of white matter and greater intrahemispheric connectivity as well as higher glucose metabolism in limbic regions in males. Many of these differences are present in childhood, but they become more prominent with adolescence, perhaps linked to puberty. Overall, they indicate complementarity between the sexes that would result in greater adaptive diversity. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Individual Differences in Personality Masculinity-Femininity: Examining the Effects of Genes, Environment, and Prenatal Hormone Transfer.

PubMed

Verweij, Karin J H; Mosing, Miriam A; Ullén, Fredrik; Madison, Guy

2016-04-01

Males and females score differently on some personality traits, but the underlying etiology of these differences is not well understood. This study examined genetic, environmental, and prenatal hormonal influences on individual differences in personality masculinity-femininity (M-F). We used Big-Five personality inventory data of 9,520 Swedish twins (aged 27 to 54) to create a bipolar M-F personality scale. Using biometrical twin modeling, we estimated the influence of genetic and environmental factors on individual differences in a M-F personality score. Furthermore, we tested whether prenatal hormone transfer may influence individuals' M-F scores by comparing the scores of twins with a same-sex versus those with an opposite-sex co-twin. On average, males scored 1.09 standard deviations higher than females on the created M-F scale. Around a third of the variation in M-F personality score was attributable to genetic factors, while family environmental factors had no influence. Males and females from opposite-sex pairs scored significantly more masculine (both approximately 0.1 SD) than those from same-sex pairs. In conclusion, genetic influences explain part of the individual differences in personality M-F, and hormone transfer from the male to the female twin during pregnancy may increase the level of masculinization in females. Additional well-powered studies are needed to clarify this association and determine the underlying mechanisms in both sexes.

Do you see what I see? Sex differences in the discrimination of facial emotions during adolescence.

PubMed

Lee, Nikki C; Krabbendam, Lydia; White, Thomas P; Meeter, Martijn; Banaschewski, Tobias; Barker, Gareth J; Bokde, Arun L W; Büchel, Christian; Conrod, Patricia; Flor, Herta; Frouin, Vincent; Heinz, Andreas; Garavan, Hugh; Gowland, Penny; Ittermann, Bernd; Mann, Karl; Paillère Martinot, Marie-Laure; Nees, Frauke; Paus, Tomas; Pausova, Zdenka; Rietschel, Marcella; Robbins, Trevor; Fauth-Bühler, Mira; Smolka, Michael N; Gallinat, Juergen; Schumann, Gunther; Shergill, Sukhi S

2013-12-01

During adolescence social relationships become increasingly important. Establishing and maintaining these relationships requires understanding of emotional stimuli, such as facial emotions. A failure to adequately interpret emotional facial expressions has previously been associated with various mental disorders that emerge during adolescence. The current study examined sex differences in emotional face processing during adolescence. Participants were adolescents (n = 1951) with a target age of 14, who completed a forced-choice emotion discrimination task. The stimuli used comprised morphed faces that contained a blend of two emotions in varying intensities (11 stimuli per set of emotions). Adolescent girls showed faster and more sensitive perception of facial emotions than boys. However, both adolescent boys and girls were most sensitive to variations in emotion intensity in faces combining happiness and sadness, and least sensitive to changes in faces comprising fear and anger. Furthermore, both sexes overidentified happiness and anger. However, the overidentification of happiness was stronger in boys. These findings were not influenced by individual differences in the level of pubertal maturation. These results indicate that male and female adolescents differ in their ability to identify emotions in morphed faces containing emotional blends. The findings provide information for clinical studies examining whether sex differences in emotional processing are related to sex differences in the prevalence of psychiatric disorders within this age group.

Air pollution and respiratory hospital admissions in greater Paris: exploring sex differences.

PubMed

Granados-Canal, D J; Chardon, B; Lefranc, A; Gremy, I

2005-01-01

The subject of sex and gender differences is relevant to the study of health effects of environmental exposures. In this study the authors aim at assessing the differences that may exist between males and females regarding short-term air pollution health effects. They studied the short-term relationships between air pollution levels and respiratory hospital admissions in greater Paris area for patients older than 15 years between 2000 and 2003. They also conducted time series analyses by using generalized additive models. For an increase of 10 microg/m3 in the air pollutant levels, the increase in relative risk of hospitalization was higher for males than for females and was significant only for males. These differences may not result solely from differences in biological susceptibility to air pollution because other factors related to gender (differences in individual exposures, in health care management, and so on) may play a role.

Does sexual selection explain human sex differences in aggression?

PubMed

Archer, John

2009-08-01

I argue that the magnitude and nature of sex differences in aggression, their development, causation, and variability, can be better explained by sexual selection than by the alternative biosocial version of social role theory. Thus, sex differences in physical aggression increase with the degree of risk, occur early in life, peak in young adulthood, and are likely to be mediated by greater male impulsiveness, and greater female fear of physical danger. Male variability in physical aggression is consistent with an alternative life history perspective, and context-dependent variability with responses to reproductive competition, although some variability follows the internal and external influences of social roles. Other sex differences, in variance in reproductive output, threat displays, size and strength, maturation rates, and mortality and conception rates, all indicate that male aggression is part of a sexually selected adaptive complex. Physical aggression between partners can be explained using different evolutionary principles, arising from the conflicts of interest between males and females entering a reproductive alliance, combined with variability following differences in societal gender roles. In this case, social roles are particularly important since they enable both the relatively equality in physical aggression between partners from Western nations, and the considerable cross-national variability, to be explained.

Mineralocorticoid receptor haplotypes sex-dependently moderate depression susceptibility following childhood maltreatment.

PubMed

Vinkers, Christiaan H; Joëls, Marian; Milaneschi, Yuri; Gerritsen, Lotte; Kahn, René S; Penninx, Brenda W J H; Boks, Marco P M

2015-04-01

The MR is an important regulator of the hypothalamic-pituitary-adrenal (HPA) axis and a prime target for corticosteroids. There is increasing evidence from both clinical and preclinical studies that the MR has different effects on behavior and mood in males and females. To investigate the hypothesis that the MR sex-dependently influences the relation between childhood maltreatment and depression, we investigated three common and functional MR haplotypes (GA, CA, and CG haplotype, based on rs5522 and rs2070951) in a population-based cohort (N = 665) and an independent clinical cohort from the Netherlands Study of Depression and Anxiety (NESDA) (N = 1639). The CA haplotype sex-dependently moderated the relation between childhood maltreatment and depressive symptoms both in the population-based sample (sex × maltreatment × haplotype: β = -4.07, P = 0.029) and in the clinical sample (sex × maltreatment × haplotype, β = -2.40, P = 0.011). Specifically, female individuals in the population-based sample were protected (β = -4.58, P = 2.0 e(-5)), whereas males in the clinical sample were at increased risk (β = 2.54, P = 0.0022). In line with these results, female GA haplotype carriers displayed increased vulnerability in the population-based sample (β = 4.58, P = 7.5 e(-5)) whereas male CG-carriers showed increased resilience in the clinical sample (β = -2.71, P = 0.016). Consistently, we found a decreased lifetime MDD risk for male GA haplotype carriers following childhood maltreatment but an increased risk for male CA haplotype carriers in the clinical sample. In both samples, sex-dependent effects were observed for GA-GA diplotype carriers. In summary, sex plays an important role in determining whether functional genetic variation in MR is beneficial or detrimental, with an apparent female advantage for the CA haplotype but male advantage for the GA and CG haplotype. These sex-dependent effects of MR on depression susceptibility following childhood maltreatment are relevant in light of the increased prevalence of mood disorders in women and point to a sex-specific role of MR in the etiology of depression following childhood maltreatment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Impact of Age and Sex on Response to Asthma Therapy.

PubMed

Dunn, Ryan M; Lehman, Erik; Chinchilli, Vernon M; Martin, Richard J; Boushey, Homer A; Israel, Elliot; Kraft, Monica; Lazarus, Stephen C; Lemanske, Robert F; Lugogo, Njira L; Peters, Stephen P; Sorkness, Christine A; Szefler, Stanley; Wechsler, Michael E

2015-09-01

Age and sex are associated with differences in asthma prevalence and morbidity. To determine if age and sex associate with distinct phenotypes and a variable response to therapy in subjects with mild to moderate asthma. We used Asthma Clinical Research Network data to determine the impact of age and sex on phenotypes and treatment failures among subjects participating in 10 trials from 1993 to 2003. A total of 1,200 subjects were identified (median age, 30.4 yr; male, 520 [43.3%]; female, 680 [56.7%]) and analyzed. A higher proportion of subjects greater than or equal to 30 years old experienced treatment failures (17.3% vs. 10.3%; odds ratio [OR], 1.82; confidence interval [CI], 1.30-2.54; P < 0.001), and rates increased proportionally with increasing age older than 30 across the cohort (OR per yr, 1.02 [CI, 1.01-1.04]; OR per 5 yr, 1.13 [CI, 1.04-1.22]; P < 0.001). Lower lung function and longer duration of asthma were associated with a higher risk of treatment failures. A higher proportion of subjects greater than or equal to 30 years old receiving controller therapy experienced treatment failures. When stratified by specific therapy, treatment failures increased consistently for every year older than age 30 in subjects on inhaled corticosteroids (OR per year, 1.03; CI, 1.01-1.07). Females had a slightly higher FEV1 % predicted (84.5% vs. 81.1%; P < 0.001) but similar asthma control measures. There was not a statistically significant difference in treatment failures between females and males (15.2% vs. 11.7%; P = 0.088). Older age is associated with an increased risk of treatment failure, particularly in subjects taking inhaled corticosteroids. There was no significant difference in treatment failures between sexes.

Impact of Age and Sex on Response to Asthma Therapy

PubMed Central

Dunn, Ryan M.; Lehman, Erik; Chinchilli, Vernon M.; Martin, Richard J.; Boushey, Homer A.; Israel, Elliot; Kraft, Monica; Lazarus, Stephen C.; Lemanske, Robert F.; Lugogo, Njira L.; Peters, Stephen P.; Sorkness, Christine A.; Szefler, Stanley

2015-01-01

Rationale: Age and sex are associated with differences in asthma prevalence and morbidity. Objectives: To determine if age and sex associate with distinct phenotypes and a variable response to therapy in subjects with mild to moderate asthma. Methods: We used Asthma Clinical Research Network data to determine the impact of age and sex on phenotypes and treatment failures among subjects participating in 10 trials from 1993 to 2003. Measurements and Main Results: A total of 1,200 subjects were identified (median age, 30.4 yr; male, 520 [43.3%]; female, 680 [56.7%]) and analyzed. A higher proportion of subjects greater than or equal to 30 years old experienced treatment failures (17.3% vs. 10.3%; odds ratio [OR], 1.82; confidence interval [CI], 1.30–2.54; P < 0.001), and rates increased proportionally with increasing age older than 30 across the cohort (OR per yr, 1.02 [CI, 1.01–1.04]; OR per 5 yr, 1.13 [CI, 1.04–1.22]; P < 0.001). Lower lung function and longer duration of asthma were associated with a higher risk of treatment failures. A higher proportion of subjects greater than or equal to 30 years old receiving controller therapy experienced treatment failures. When stratified by specific therapy, treatment failures increased consistently for every year older than age 30 in subjects on inhaled corticosteroids (OR per year, 1.03; CI, 1.01–1.07). Females had a slightly higher FEV1 % predicted (84.5% vs. 81.1%; P < 0.001) but similar asthma control measures. There was not a statistically significant difference in treatment failures between females and males (15.2% vs. 11.7%; P = 0.088). Conclusions: Older age is associated with an increased risk of treatment failure, particularly in subjects taking inhaled corticosteroids. There was no significant difference in treatment failures between sexes. PMID:26068329

Sex Differences in Landing Biomechanics and Postural Stability During Adolescence: A Systematic Review with Meta-Analyses.

PubMed

Holden, Sinéad; Boreham, Colin; Delahunt, Eamonn

2016-02-01

The adolescent 'growth spurt' results in rapid growth of the skeletal system. It has been theorised that absence of a concomitant increase in muscular adaptations in female athletes may predispose them to an increased risk of anterior cruciate ligament injuries. To determine if sex differences exist in landing biomechanics and postural stability of adolescent athletes; with a further objective of determining if such differences are propagated during adolescence. The following databases were searched: MEDLINE, EMBASE, CINAHL, PEDro, PubMed, SPORTDiscus and Web of Science. Research papers were identified by including search terms for neuromuscular control, lower limb and pubertal development. Studies were required to be written in English; report on biomechanical analyses; include landing or postural control tasks; be cross-sectional or longitudinal; and include healthy adolescent/pubertal subjects. A modified version of the Strengthening the Reporting of Observational studies in Epidemiology checklist was used to rate methodological quality. Meta-analyses were performed when more than one study reported on an outcome measure. Sixteen articles were included. The overall methodological quality of evaluated studies was low (mean score = 5.75/10 points). Adolescent females exhibited increased knee valgus with increasing maturity. There was no consensus on sex differences in postural stability. With increasing maturation, females are characterized by increased knee valgus during landing tasks. To date, no research has longitudinally investigated postural stability development during adolescence in females, despite the importance of postural control training in injury prevention programmes. Therefore, further research on this topic is warranted.

Use of Social Media in Different Contexts of Information Seeking: Effects of Sex and Problemsolving Style

ERIC Educational Resources Information Center

Kim, Kyung­-Sun; Sin, Sei­-Ching Joanna

2015-01-01

Introduction: Social media are increasingly popular and emerging as important information sources. The study investigates how users' sex and problem-solving style affect their use and evaluation of social media in two contexts. Method: A Web survey including the problem solving inventory (problem solving inventory) was used to collect data. Over…

Development of Face Recognition in 5- to 15-Year-Olds

ERIC Educational Resources Information Center

Kinnunen, Suna; Korkman, Marit; Laasonen, Marja; Lahti-Nuuttila, Pekka

2013-01-01

This study focuses on the development of face recognition in typically developing preschool- and school-aged children (aged 5 to 15 years old, "n" = 611, 336 girls). Social predictors include sex differences and own-sex bias. At younger ages, the development of face recognition was rapid and became more gradual as the age increased up…

Sex differences on the competitive place task in the water maze: The influence of peripheral pool time on spatial navigation performance in rats.

PubMed

Devan, Bryan D; Tobin, Elizabeth L; Dunn, Emily N; Magalis, Christopher

2016-11-01

This study investigated sex differences on the competitive place version of the Morris water maze task to determine whether potential strategy differences would emerge during any phase of the study but in particular on the competitive place phase. Previous findings indicate that this version of the task is highly sensitive to measures that disrupt NMDA-dependent synaptic plasticity within the hippocampus during memory consolidation (McDonald et al., 2005). The present findings revealed significant sex differences during all phases of the study, including Phase I with standard place training to located a hidden platform/goal, Phase II mass training to a new place with the platform/goal relocated to the diagonally opposite quadrant and Phase III, competitive place probe test with the platform removed to measure spatial behaviour directed at either location. The findings showed no sex difference in escape latency and other standard performance measures during the first two phases, initial place acquisition and mass training to a new location. A very subtle male advantage in visiting both Old and New place locations during the third phase place competition test was observed, however, in the time spent swimming in the periphery of the pool, the pool wall (Zone C - outer third radial distance) was increased for females during all phases of the study, suggesting a general effect may have influenced place location search behaviour of the females. Increased peripheral pool time may represent a female preference for approaching the wall, a local cue. Alternatively, the possibility that increased peripheral swimming/thigmotaxis may represent hormonal influences interacting with strategic preferences were discussed, though no definitive conclusions about sex differences in cognitive-spatial performance or memory consolidation were inferred from the present findings. The findings suggest that mixed results reported in the literature by others may be due in part to an interaction with a persistent peripheral pool swimming response demonstrated in female rats. Copyright © 2016 Elsevier B.V. All rights reserved.

Structural connections in the brain in relation to gender identity and sexual orientation.

PubMed

Burke, Sarah M; Manzouri, Amir H; Savic, Ivanka

2017-12-20

Both transgenderism and homosexuality are facets of human biology, believed to derive from different sexual differentiation of the brain. The two phenomena are, however, fundamentally unalike, despite an increased prevalence of homosexuality among transgender populations. Transgenderism is associated with strong feelings of incongruence between one's physical sex and experienced gender, not reported in homosexual persons. The present study searches to find neural correlates for the respective conditions, using fractional anisotropy (FA) as a measure of white matter connections that has consistently shown sex differences. We compared FA in 40 transgender men (female birth-assigned sex) and 27 transgender women (male birth-assigned sex), with both homosexual (29 male, 30 female) and heterosexual (40 male, 40 female) cisgender controls. Previously reported sex differences in FA were reproduced in cis-heterosexual groups, but were not found among the cis-homosexual groups. After controlling for sexual orientation, the transgender groups showed sex-typical FA-values. The only exception was the right inferior fronto-occipital tract, connecting parietal and frontal brain areas that mediate own body perception. Our findings suggest that the neuroanatomical signature of transgenderism is related to brain areas processing the perception of self and body ownership, whereas homosexuality seems to be associated with less cerebral sexual differentiation.

Diabetes mellitus in Jamaica: sex differences in burden, risk factors, awareness, treatment and control in a developing country.

PubMed

Cunningham-Myrie, Colette; Younger-Coleman, Novie; Tulloch-Reid, Marshall; McFarlane, Shelly; Francis, Damian; Ferguson, Trevor; Gordon-Strachan, Georgiana; Wilks, Rainford

2013-11-01

The objective of this study was to provide valid estimates of the burden of and risk factors for diabetes mellitus by sex in Jamaica, a predominantly Black, middle-income and developing country. The Jamaica Health and Lifestyle Survey 2008 examined a nationally representative sample of 2848 Jamaicans aged 15-74. Parameter estimates and 95% confidence intervals [CI] were weighted for non-response as well as age and sex of the source population. Sex differences in risk factors and diabetes prevalence, awareness, treatment and control were estimated in multivariable models. Population-attributable fractions (PAFs) of obesity on diabetes mellitus were estimated in both sexes. The prevalence of diabetes mellitus was 7.9% (95% CI: 6.7-9.1%), significantly higher in women than men 9.3% vs. 6.4% (P = 0.02) and increasing with age. Seventy-six percentage of persons with diabetes mellitus were aware of their status; urban women and rural men were less likely to be aware. Diabetes control (43% overall) was less common in higher-income men, but more common in higher-income women. Persons without health insurance were less likely to control their diabetes. The prevalence of diabetes risk factors was higher in women than men. Increased waist circumference (≥94 cm [men]/≥80 cm [women]), overweight/obesity (body mass index ≥ 25 kg/m(2)) and low physical activity/inactivity were associated with PAFs for diabetes mellitus of 27%, 37% and 15%, respectively, in men and 77%, 54% and 24%, respectively, in women. Prevalence of diabetes mellitus and its risk factors is high in Jamaica, especially among women, and national programmes to stem the diabetes mellitus epidemic should take these sex differences into consideration. © 2013 John Wiley & Sons Ltd.

Mood, Meth, Condom Use, and Gender: Latent Growth Curve Modeling Results from a Randomized Trial.

PubMed

Pitpitan, Eileen V; Semple, Shirley J; Zians, Jim; Strathdee, Steffanie A; Patterson, Thomas L

2018-05-12

Methamphetamine use poses increased risk for HIV and other sexually transmitted infections. There is robust evidence that methamphetamine use increases sexual risk behavior, like condomless sex, primarily among men who have sex with men but also among heterosexual women and men. Gender differences have been found among women and men who use meth, and there is a high degree of interconnectedness between meth use, depression, and condomless sex. The aims of the current study are to evaluate the efficacy of a theory-based, tri-focal intervention designed to reduce depression, meth use, and condomless sex among women and men, and to examine gender as a moderator of efficacy. A total of 432 HIV-negative women and men who use meth participated in a two-arm randomized controlled trial and completed baseline and follow-up assessments at 4, 8, and 12 months. We used latent growth curve modeling techniques to analyze the data. Results showed that while all participants exhibited reductions in depression, meth use, and condomless sex, the intervention and comparison groups did not differ in changes over time. However, we did find a significant gender moderation effect, such that among men, those in the intervention arm reported greater reductions in meth use relative to those in the comparison group; reduced meth use was associated with reduced condomless sex, but not depression. In contrast, women in the intervention condition did not differ from women in the comparison condition in changes in any of the three outcome variables. Interventions targeting heterosexual women and men who use meth must be gender-specific, and take into account the unique vulnerabilities and experiences of women, including the perceived positive aspects of using meth, gendered power dynamics, higher depression, and violence.

Temporal Trends in Sex Differences With Regard to Stroke Incidence: The Dijon Stroke Registry (1987-2012).

PubMed

Giroud, Marie; Delpont, Benoit; Daubail, Benoit; Blanc, Christelle; Durier, Jérôme; Giroud, Maurice; Béjot, Yannick

2017-04-01

We evaluated temporal trends in stroke incidence between men and women to determine whether changes in the distribution of vascular risk factors have influenced sex differences in stroke epidemiology. Patients with first-ever stroke including ischemic stroke, spontaneous intracerebral hemorrhage, subarachnoid hemorrhage, and undetermined stroke between 1987 and 2012 were identified through the population-based registry of Dijon, France. Incidence rates were calculated for age groups, sex, and stroke subtypes. Sex differences and temporal trends (according to 5-year time periods) were evaluated by calculating incidence rate ratios (IRRs) with Poisson regression. Four thousand six hundred and fourteen patients with a first-ever stroke (53.1% women) were recorded. Incidence was lower in women than in men (112 versus 166 per 100 000/y; IRR, 0.68; P <0.001), especially in age group 45 to 84 years, and for both ischemic stroke and intracerebral hemorrhage. From 1987 to 2012, the lower incidence of overall stroke in women was stable (IRR ranging between 0.63 and 0.72 according to study periods). When considering stroke subtype, a slight increase in the incidence of ischemic stroke was observed in both men (IRR, 1.011; 95% confidence interval, 1.005-1.016; P =0.001) and women (IRR, 1.013; 95% confidence interval, 1.007-1.018; P =0.001). The sex gap in incidence remained unchanged in ischemic stroke and intracerebral hemorrhage. Conversely, the lower subarachnoid hemorrhage incidence in women vanished with time because of an increasing incidence. The sex gap in stroke incidence did not change with time except for subarachnoid hemorrhage. Despite lower rates, more women than men experience an incident stroke each year because of a longer life expectancy. © 2017 American Heart Association, Inc.

Cognitive function and associated factors among older people in Taiwan: age and sex differences.

PubMed

Li, Cheng-Lun; Hsu, Hui-Chuan

2015-01-01

The aim of this study was to examine cognitive function and the risk and the protective factors by age and sex among Taiwanese older people. The data were from a nation-representative panel of older people in Taiwan. The participants completing both the 2003 and 2007 waves were included for analysis in this study (n=3228). Descriptive analysis and generalized linear model were applied, and the samples were stratified by age groups and by sex. The factors related to higher cognitive function at the intercept included being younger, male, higher education, and doing unpaid work. At the time slope, the age effect and physical function difficulties would reduce the cognitive function across time, while education and providing informational support would increase the cognitive function across time. There were age- and sex-differences in the factors related to cognitive function, particularly on the working status and social participation. Different health promotion strategies to target these populations should be accordingly developed. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Sex differences in the developing brain as a source of inherent risk

PubMed Central

McCarthy, Margaret M.

2016-01-01

Brain development diverges in males and females in response to androgen production by the fetal testis. This sexual differentiation of the brain occurs during a sensitive window and induces enduring neuroanatomical and physiological changes that profoundly impact behavior. What we know about the contribution of sex chromosomes is still emerging, highlighting the need to integrate multiple factors into understanding sex differences, including the importance of context. The cellular mechanisms are best modeled in rodents and have provided both unifying principles and surprising specifics. Markedly distinct signaling pathways direct differentiation in specific brain regions, resulting in mosaicism of relative maleness, femaleness, and sameness through-out the brain, while canalization both exaggerates and constrains sex differences. Non-neuronal cells and inflammatory mediators are found in greater number and at higher levels in parts of male brains. This higher baseline of inflammation is speculated to increase male vulnerability to developmental neuropsychiatric disorders that are triggered by inflammation. PMID:28179808

Work-Family Conflict and the Sex Difference in Depression Among Training Physicians.

PubMed

Guille, Constance; Frank, Elena; Zhao, Zhuo; Kalmbach, David A; Nietert, Paul J; Mata, Douglas A; Sen, Srijan

2017-12-01

Depression is common among training physicians and may disproportionately affect women. The identification of modifiable risk factors is key to reducing this disease burden and its negative impact on patient care and physician career attrition. To determine the presence and magnitude of a sex difference in depressive symptoms and work-family conflict among training physicians; and if work-family conflict impacts the sex difference in depressive symptoms among training physicians. A prospective longitudinal cohort study of medical internship in the United States during the 2015 to 2016 academic year in which 3121 interns were recruited across all specialties from 44 medical institutions. Prior to and during their internship year, participants reported the degree to which work responsibilities interfered with family life using the Work Family Conflict Scale and depressive symptoms using the Patient Health Questionnaire-9 (PHQ-9). Mean (SD) participant age was 27.5 (2.7) years, and 1571 participants (49.7%) were women. Both men and women experienced a marked increase in depressive symptoms during their internship year, with the increase being statistically significantly greater for women (men: mean increase in PHQ-9, 2.50; 95% CI, 2.26-2.73 vs women: mean increase, 3.20; 95% CI, 2.97-3.43). When work-family conflict was accounted for, the sex disparity in the increase in depressive symptoms decreased by 36%. Our study demonstrates that depressive symptoms increase substantially during the internship year for men and women, but that this increase is greater for women. The study also identifies work-family conflict as an important potentially modifiable factor that is associated with elevated depressive symptoms in training physicians. Systemic modifications to alleviate conflict between work and family life may improve physician mental health and reduce the disproportionate depression disease burden for female physicians. Given that depression among physicians is associated with poor patient care and career attrition, efforts to alleviate depression among physicians has the potential to reduce the negative consequences associated with this disease.

Sex differences in the expression of lung inflammatory mediators in response to ozone

PubMed Central

Cabello, Noe; Mishra, Vikas; Sinha, Utkarshna; DiAngelo, Susan L.; Chroneos, Zissis C.; Ekpa, Ndifreke A.; Cooper, Timothy K.; Caruso, Carla R.

2015-01-01

Sex differences in the incidence of respiratory diseases have been reported. Women are more susceptible to inflammatory lung disease induced by air pollution and show worse adverse pulmonary health outcomes than men. However, the mechanisms underlying these differences remain unknown. In the present study, we hypothesized that sex differences in the expression of lung inflammatory mediators affect sex-specific immune responses to environmental toxicants. We focused on the effects of ground-level ozone, a major air pollutant, in the expression and regulation of lung immunity genes. We exposed adult male and female mice to 2 ppm of ozone or filtered air (control) for 3 h. We compared mRNA levels of 84 inflammatory genes in lungs harvested 4 h postexposure using a PCR array. We also evaluated changes in lung histology and bronchoalveolar lavage fluid cell counts and protein content at 24 and 72 h postexposure. Our results revealed sex differences in lung inflammation triggered by ozone exposure and in the expression of genes involved in acute phase and inflammatory responses. Major sex differences were found in the expression of neutrophil-attracting chemokines (Ccl20, Cxcl5, and Cxcl2), the proinflammatory cytokine interleukin-6, and oxidative stress-related enzymes (Ptgs2, Nos2). In addition, the phosphorylation of STAT3, known to mediate IL-6-related immune responses, was significantly higher in ozone-exposed mice. Together, our observations suggest that a differential regulation of the lung immune response could be implicated in the observed increased susceptibility to adverse health effects from ozone observed in women vs. men. PMID:26342085

Sex Differences in Academic Rank in US Medical Schools in 2014.

PubMed

Jena, Anupam B; Khullar, Dhruv; Ho, Oliver; Olenski, Andrew R; Blumenthal, Daniel M

2015-09-15

The proportion of women at the rank of full professor in US medical schools has not increased since 1980 and remains below that of men. Whether differences in age, experience, specialty, and research productivity between sexes explain persistent disparities in faculty rank has not been studied. To analyze sex differences in faculty rank among US academic physicians. We analyzed sex differences in faculty rank using a cross-sectional comprehensive database of US physicians with medical school faculty appointments in 2014 (91,073 physicians; 9.1% of all US physicians), linked to information on physician sex, age, years since residency, specialty, authored publications, National Institutes of Health (NIH) funding, and clinical trial investigation. We estimated sex differences in full professorship, as well as a combined outcome of associate or full professorship, adjusting for these factors in a multilevel (hierarchical) model. We also analyzed how sex differences varied with specialty and whether differences were more prevalent at schools ranked highly in research. Physician sex. Academic faculty rank. In all, there were 30,464 women who were medical faculty vs 60,609 men. Of those, 3623 women (11.9%) vs 17,354 men (28.6%) had full-professor appointments, for an absolute difference of -16.7% (95% CI, -17.3% to -16.2%). Women faculty were younger and disproportionately represented in internal medicine and pediatrics. The mean total number of publications for women was 11.6 vs 24.8 for men, for a difference of -13.2 (95% CI, -13.6 to -12.7); the mean first- or last-author publications for women was 5.9 vs 13.7 for men, for a difference of -7.8 (95% CI, -8.1 to -7.5). Among 9.1% of medical faculty with an NIH grant, 6.8% (2059 of 30,464) were women and 10.3% (6237 of 60,609) were men, for a difference of -3.5% (95% CI, -3.9% to -3.1%). In all, 6.4% of women vs 8.8% of men had a trial registered on ClinicalTrials.gov, for a difference of -2.4% (95% CI, -2.8% to -2.0%). After multivariable adjustment, women were less likely than men to have achieved full-professor status (absolute adjusted difference in proportion, -3.8%; 95% CI, -4.4% to -3.3%). Sex-differences in full professorship were present across all specialties and did not vary according to whether a physician's medical school was ranked highly in terms of research funding. Among physicians with faculty appointments at US medical schools, there were sex differences in academic faculty rank, with women substantially less likely than men to be full professors, after accounting for age, experience, specialty, and measures of research productivity.

Assessment of sex specific endocrine disrupting effects in the prenatal and pre-pubertal rodent brain.

PubMed

Rebuli, Meghan E; Patisaul, Heather B

2016-06-01

Brain sex differences are found in nearly every region of the brain and fundamental to sexually dimorphic behaviors as well as disorders of the brain and behavior. These differences are organized during gestation and early adolescence and detectable prior to puberty. Endocrine disrupting compounds (EDCs) interfere with hormone action and are thus prenatal exposure is hypothesized to disrupt the formation of sex differences, and contribute to the increased prevalence of pediatric neuropsychiatric disorders that present with a sex bias. Available evidence for the ability of EDCs to impact the emergence of brain sex differences in the rodent brain was reviewed here, with a focus on effects detected at or before puberty. The peer-reviewed literature was searched using PubMed, and all relevant papers published by January 31, 2015 were incorporated. Endpoints of interest included molecular cellular and neuroanatomical effects. Studies on behavioral endpoints were not included because numerous reviews of that literature are available. The hypothalamus was found to be particularly affected by estrogenic EDCs in a sex, time, and exposure dependent manner. The hippocampus also appears vulnerable to endocrine disruption by BPA and PCBs although there is little evidence from the pre-pubertal literature to make any conclusions about sex-specific effects. Gestational EDC exposure can alter fetal neurogenesis and gene expression throughout the brain including the cortex and cerebellum. The available literature primarily focuses on a few, well characterized EDCs, but little data is available for emerging contaminants. The developmental EDC exposure literature demonstrates evidence of altered neurodevelopment as early as fetal life, with sex specific effects observed throughout the brain even before puberty. Copyright © 2015 Elsevier Ltd. All rights reserved.

Differences in sexual behaviour and sexual practices of adolescents in Nigeria based on sex and self-reported HIV status.

PubMed

Folayan, Morenike O; Odetoyinbo, Morolake; Brown, Brandon; Harrison, Abigail

2014-12-06

Sexual behaviour and sexual practices affect the risk for acquisition and transmission of HIV infection. This study tries to identify differences in sexual behaviour (condom use with non-marital partners, multiple sexual partnerships transactional sex and age mixing in sexual relationships), sexual practices (oral, anal and vagina sex), and forced sexual initiation based on sex and HIV status of adolescents in Nigeria. Face to face interviewer-administered questionnaires were used to collect information from a nationally representative sample of 10-19 years old adolescents residing in Nigeria. Data included information on age of sexual debut, sexual behaviour and sexual practices. Association between HIV status, sex, sexual behaviour and sexual practices, and predictors of use of condoms during the last vaginal sexual intercourse were determined. More self-reported HIV positive than HIV negative females had experienced forced sexual initiation (p = 0.008). Significantly more female than male adolescents had engaged in transactional sex (p < 0.001) and had sex with partners who were older than them by 10 years or more (p < 0.001). Vaginal (95.2%), oral (26.6%) and anal (7.8%) sex were practiced by male and females irrespective of HIV status. More females reported oral sex (p = 0.001). Being a female (p = 0.001), having genital itching in the last 12 months (p = 0.04)and having engaged in anal sex in the last 12 months (p = 0.009) reduced the odds of using a condom at last vaginal intercourse. Having a HIV positive or negative status did not significantly increase the odds of using a condom at last vaginal intercourse. Differences in sexual behaviour and sexual practices of adolescents was observed based on sex and not on HIV status. History of forced sex initiation however differed by HIV status. Tailored interventions for male and female adolescents are required to reduce their risk of HIV infection. Tailored interventions are also required for adolescents living with HIV to improve their sexual and reproductive health.

Sex differences in panic-relevant responding to a 10% carbon dioxide-enriched air biological challenge.

PubMed

Nillni, Yael I; Berenz, Erin C; Rohan, Kelly J; Zvolensky, Michael J

2012-01-01

The current study examined sex differences in psychological (i.e., self-reported anxiety, panic symptoms, and avoidance) and physiological (i.e., heart rate and skin conductance level) response to, and recovery from, a laboratory biological challenge. Participants were a community-recruited sample of 128 adults (63.3% women; M(age)=23.2 years, SD=8.9) who underwent a 4-min 10% CO(2)-enriched air biological challenge. As predicted, women reported more severe physical panic symptoms and avoidance (i.e., less willingness to participate in another challenge) and demonstrated increased heart rate as compared to men above and beyond the variance accounted for by other theoretically relevant variables (recent panic attack history, neuroticism, and anxiety sensitivity). Additionally, women demonstrated a faster rate of recovery with respect to heart rate compared to men. These results are in line with literature documenting sex-specific differences in panic psychopathology, and results are discussed in the context of possible mechanisms underlying sex differences in panic vulnerability. Copyright © 2011 Elsevier Ltd. All rights reserved.

Sex differences in brain and behavior in adolescence: Findings from the Philadelphia Neurodevelopmental Cohort.

PubMed

Gur, Raquel E; Gur, Ruben C

2016-11-01

Sex differences in brain and behavior were investigated across the lifespan. Parameters include neurobehavioral measures linkable to neuroanatomic and neurophysiologic indicators of brain structure and function. Sexual differentiation of behavior has been related to organizational factors during sensitive periods of development, with adolescence and puberty gaining increased attention. Adolescence is a critical developmental period where transition to adulthood is impacted by multiple factors that can enhance vulnerability to brain dysfunction. Here we highlight sex differences in neurobehavioral measures in adolescence that are linked to brain function. We summarize neuroimaging studies examining brain structure, connectivity and perfusion, underscoring the relationship to sex differences in behavioral measures and commenting on hormonal findings. We focus on relevant data from the Philadelphia Neurodevelopmental Cohort (PNC), a community-based sample of nearly 10,000 clinically and neurocognitively phenotyped youths age 8-21 of whom 1600 have received multimodal neuroimaging. These data indicate early and pervasive sexual differentiation in neurocognitive measures that is linkable to brain parameters. We conclude by describing possible clinical implications. Copyright © 2016 Elsevier Ltd. All rights reserved.

Sex differences in spatiotemporal expression of AR, ERα, and ERβ mRNA in the perinatal mouse brain.

PubMed

Mogi, Kazutaka; Takanashi, Haruka; Nagasawa, Miho; Kikusui, Takefumi

2015-01-01

It has been shown that every masculinized function might be organized by a particular contribution of androgens vs. estrogens in a critical time window. Here, we aimed to investigate the sex differences in brain testosterone levels and in the spatiotemporal dynamics of steroid receptor mRNA expression in perinatal mice, by using enzyme immunoassay and real-time PCR, respectively. We found that testosterone levels in the forebrain transiently increased around birth in male mice. During the perinatal period, levels of androgen receptor mRNA in the hypothalamus (hypo) and prefrontal cortex (PFC) were higher in male mice than in female mice. Estrogen receptor α (ERα) mRNA levels in the hypo and hippocampus were higher in male mice than in female mice before birth. In contrast, ERβ mRNA expression in the PFC was higher in female mice immediately after birth. These spatiotemporal sex differences in steroid receptor expression might contribute to organizing sex differences of not only reproductive function, but also anxiety, stress responses, and cognition in mice. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Sex differences in brain and behavior in adolescence: Findings from the Philadelphia Neurodevelopmental Cohort

PubMed Central

Gur, Raquel E.; Gur, Ruben C.

2016-01-01

Sex differences in brain and behavior were investigated across the lifespan. Parameters include neurobehavioral measures linkable to neuroanatomic and neurophysiologic indicators of brain structure and function. Sexual differentiation of behavior has been related to organizational factors during sensitive periods of development, with adolescence and puberty gaining increased attention. Adolescence is a critical developmental period where transition to adulthood is impacted by multiple factors that can enhance vulnerability to brain dysfunction. Here we highlight sex differences in neurobehavioral measures in adolescence that are linked to brain function. We summarize neuroimaging studies examining brain structure, connectivity and perfusion, underscoring the relationship to sex differences in behavioral measures and commenting on hormonal findings. We focus on relevant data from the Philadelphia Neurodevelopmental Cohort (PNC), a community-based sample of nearly 10,000 clinically and neurocognitively phenotyped youths age 8–21 of whom 1600 have received multimodal neuroimaging. These data indicate early and pervasive sexual differentiation in neurocognitive measures that is linkable to brain parameters. We conclude by describing possible clinical implications. PMID:27498084

The Effect of Sex and Gender on Diabetic Complications.

PubMed

Seghieri, Giuseppe; Policardo, Laura; Anichini, Roberto; Franconi, Flavia; Campesi, Ilaria; Cherchi, Sara; Tonolo, Giancarlo

2017-01-01

While in non-diabetic people the risk for cardiovascular disease is higher in men, diabetes completely reverts this sex-gender difference conferring to women a greater burden of cardiovascular complications. Additionally, all risk factors associated with cardiovascular disease appear to be more active in diabetic females than in their male counterparts. The reasons of this different impact of diabetes between genders are not completely clear. The aim of this review is trying to clarify these issues in a sex and gender perspective. Both genetic and hormonal factors are at the basis of sex-gender differences in diabetes, even do not explain the totality of data. Possibly women arrive later and in worse conditions to the diagnosis of diabetes, receive both diagnostic and therapeutic supports in a lesser measure and, finally, reach therapeutic goals as recommended by guidelines in a lesser extent. Further aspects of sex-gender differences in diabetic complications are represented by a more frequent prevalence of drug side effects in women, as well as by increased resistance to the action of drugs used in prevention or in the therapy of cardiovascular diseases. As to microvascular complications, the issue of sex-gender differences is even more complex, with some important differences emerging in experimental models 'in vitro', as well as in human pathology 'in vivo'. The main problem, however, also in this case, is that it is difficult to differentiate how common pathogenetic mechanisms acting in diabetes may differently impact between genders. In conclusion what is evident is that diabetes represents a 'risk magnifier' for the damage of both micro and macrovessels differently in men and in women. This issue deserves, therefore, a more careful approach from people involved in both clinical aspects and research regarding diabetes and its complications, in a sex-gender oriented perspective. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Sex Differences in the Physiological and Behavioral Effects of Chronic Oral Methylphenidate Treatment in Rats

PubMed Central

Robison, Lisa S.; Michaelos, Michalis; Gandhi, Jason; Fricke, Dennis; Miao, Erick; Lam, Chiu-Yim; Mauceri, Anthony; Vitale, Melissa; Lee, Junho; Paeng, Soyeh; Komatsu, David E.; Hadjiargyrou, Michael; Thanos, Panayotis K.

2017-01-01

Methylphenidate (MP) is a psychostimulant prescribed for Attention Deficit Hyperactivity Disorder. Previously, we developed a dual bottle 8-h-limited-access-drinking-paradigm for oral MP treatment of rats that mimics the pharmacokinetic profile of treated patients. This study assessed sex differences in response to this treatment. Male and female Sprague Dawley rats were assigned to one of three treatment groups at 4 weeks of age (n = 12/group): Control (water), low dose (LD) MP, and high dose (HD) MP. Rats drank 4 mg/kg MP (LD) or 30 mg/kg MP (HD) during the first hour, and 10 mg/kg (LD) or 60 mg/kg MP (HD) for the remaining 7 h each day. Throughout 3 months of treatment, rats were monitored for body weight, food intake, and fluid intake; as well as tested for open field behavior, circadian activity, novel object recognition, and social interaction. Chronic MP treated rats exhibited reduced fluid intake during distinct treatment weeks to a greater extent in males, and reduced total fluid intake in males only. HD MP treatment decreased body weight in both sexes, while HD MP increased total food intake in females only, likely to offset energy deficits resulting from MP-induced hyperactivity. LD and HD MP increased locomotor activity in the open field, particularly in females and during later treatment weeks. MP dose-dependently increased activity during the dark cycle of circadian testing in females, while in males hyperactivity was only exhibited by HD rats. HD MP increased center activity to a greater extent in males, while MP increased rearing behavior in females only. MP had no effect on social behavior or novel object recognition in either sex. This study concludes that chronic oral MP treatment at clinically-relevant dosages has significant effects on food intake, body weight, open field behavior, and wake cycle activity. Particularly marked sex differences were apparent for locomotor activity, with females being significantly more sensitive to the hyperactivating effects of the drug. These findings suggest that chronic MP exposure beginning in adolescence can have significant behavioral effects that are both dose- and sex-dependent, and raise concerns regarding the reversibility of these effects post-discontinuation of treatment. PMID:28400722

Oral and anal sex are key to sustaining gonorrhoea at endemic levels in MSM populations: a mathematical model.

PubMed

Hui, B; Fairley, C K; Chen, M; Grulich, A; Hocking, J; Prestage, G; Walker, S; Law, M; Regan, D

2015-08-01

Despite early treatment of urethral infection, gonorrhoea is endemic in urban populations of men who have sex with men (MSM) in Australia. By contrast, gonorrhoea is not common in urban heterosexual populations. Sexual activities among MSM usually involve anal or oral sex, and as these behaviours are becoming increasingly common among heterosexuals, there is a need to investigate their roles in transmission of gonorrhoea. We developed individual-based models of transmission of gonorrhoea in MSM and heterosexuals that incorporate anatomical site-specific transmission of gonorrhoea. We estimated the probabilities of transmission for anal sex and oral sex by calibrating an MSM model against prevalence of gonorrhoea and sexual activity data. These probabilities were then applied to a heterosexual model in order to examine whether gonorrhoea can persist in a heterosexual population through the addition of anal sex and oral sex. In the MSM model, gonorrhoea can persist despite prompt treatment of urethral infections. The probability of gonorrhoea persisting is reduced if use of condom for oral sex is increased to more than 15% of acts. Assuming that treatment of symptomatic infections is prompt, gonorrhoea is unlikely to persist in a heterosexual population even with the addition of anal and oral sex. Our models suggest that oral sex has an important role in sustaining gonorrhoea in a population of MSM by providing a pool of untreated asymptomatic infection. The importance of anal sex or oral sex in sustaining gonorrhoea in a heterosexual population remains uncertain due to the lack of information linking different types of sex acts and transmissibility. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Changes in mortality inequalities across occupations in Japan: a national register based study of absolute and relative measures, 1980-2010

PubMed Central

Toyokawa, Satoshi; Tamiya, Nanako; Takahashi, Hideto; Noguchi, Haruko; Kobayashi, Yasuki

2017-01-01

Objective Changes in mortality inequalities across socioeconomic groups have been a substantial public health concern worldwide. We investigated changes in absolute/relative mortality inequalities across occupations, and the contribution of different diseases to inequalities in tandem with the restructuring of the Japanese economy. Methods Using complete Japanese national death registries from 5 year intervals (1980–2010), all cause and cause specific age standardised mortality rates (ASMR per 100 000 people standardised using the Japanese standard population in 1985, aged 30–59 years) across 12 occupations were computed. Absolute and relative inequalities were measured in ASMR differences (RDs) and ASMR ratios (RRs) among occupations in comparison with manufacturing workers (reference). We also estimated the changing contribution of different diseases by calculating the differences in ASMR change between 1995 and 2010 for occupations and reference. Results All cause ASMRs tended to decrease in both sexes over the three decades except for male managers (increased by 71% points, 1995–2010). RDs across occupations were reduced for both sexes (civil servants 233.5 to −1.9 for men; sales workers 63.3 to 4.5 for women) but RRs increased for some occupations (professional workers 1.38 to 1.70; service workers 2.35 to 3.73) for men and decreased for women from 1980 to 2010. Male relative inequalities widened among farmer, fishery and service workers, because the percentage declines were smaller in these occupations. Cerebrovascular disease and cancer were the main causes of the decrease in mortality inequalities among sexes but the incidence of suicide increased among men, thereby increasing sex related inequalities. Conclusions Absolute inequality trends in mortality across occupations decreased in both sexes, while relative inequality trends were heterogeneous in Japan. The main drivers of narrowing and widening mortality inequalities were cerebrovascular disease and suicide, respectively. Future public health efforts will benefit from eliminating residual inequalities in mortality by considering the contribution of the causes of death and socioeconomic status stratification. PMID:28877942

Changes in mortality inequalities across occupations in Japan: a national register based study of absolute and relative measures, 1980-2010.

PubMed

Tanaka, Hirokazu; Toyokawa, Satoshi; Tamiya, Nanako; Takahashi, Hideto; Noguchi, Haruko; Kobayashi, Yasuki

2017-09-05

Changes in mortality inequalities across socioeconomic groups have been a substantial public health concern worldwide. We investigated changes in absolute/relative mortality inequalities across occupations, and the contribution of different diseases to inequalities in tandem with the restructuring of the Japanese economy. Using complete Japanese national death registries from 5 year intervals (1980-2010), all cause and cause specific age standardised mortality rates (ASMR per 100 000 people standardised using the Japanese standard population in 1985, aged 30-59 years) across 12 occupations were computed. Absolute and relative inequalities were measured in ASMR differences (RDs) and ASMR ratios (RRs) among occupations in comparison with manufacturing workers (reference). We also estimated the changing contribution of different diseases by calculating the differences in ASMR change between 1995 and 2010 for occupations and reference. All cause ASMRs tended to decrease in both sexes over the three decades except for male managers (increased by 71% points, 1995-2010). RDs across occupations were reduced for both sexes (civil servants 233.5 to -1.9 for men; sales workers 63.3 to 4.5 for women) but RRs increased for some occupations (professional workers 1.38 to 1.70; service workers 2.35 to 3.73) for men and decreased for women from 1980 to 2010. Male relative inequalities widened among farmer, fishery and service workers, because the percentage declines were smaller in these occupations. Cerebrovascular disease and cancer were the main causes of the decrease in mortality inequalities among sexes but the incidence of suicide increased among men, thereby increasing sex related inequalities. Absolute inequality trends in mortality across occupations decreased in both sexes, while relative inequality trends were heterogeneous in Japan. The main drivers of narrowing and widening mortality inequalities were cerebrovascular disease and suicide, respectively. Future public health efforts will benefit from eliminating residual inequalities in mortality by considering the contribution of the causes of death and socioeconomic status stratification. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Survival after out-of-hospital cardiac arrest in relation to sex: a nationwide registry-based study.

PubMed

Wissenberg, Mads; Hansen, Carolina Malta; Folke, Fredrik; Lippert, Freddy K; Weeke, Peter; Karlsson, Lena; Rajan, Shahzleen; Søndergaard, Kathrine Bach; Kragholm, Kristian; Christensen, Erika Frischknecht; Nielsen, Søren L; Køber, Lars; Gislason, Gunnar H; Torp-Pedersen, Christian

2014-09-01

Crude survival has increased following an out-of-hospital cardiac arrest (OHCA). We aimed to study sex-related differences in patient characteristics and survival during a 10-year study period. Patients≥12 years old with OHCA of a presumed cardiac cause, and in whom resuscitation was attempted, were identified through the Danish Cardiac Arrest Registry 2001-2010. A total of 19,372 patients were included. One-third were female, with a median age of 75 years (IQR 65-83). Compared to females, males were five years younger; and less likely to have severe comorbidities, e.g., chronic obstructive pulmonary disease (12.8% vs. 16.5%); but more likely to have arrest outside of the home (29.4% vs. 18.7%), receive bystander CPR (32.9% vs. 25.9%), and have a shockable rhythm (32.6% vs. 17.2%), all p<0.001. Thirty-day crude survival increased in males (3.0% in 2001 to 12.9% in 2010); and in females (4.8% in 2001 to 6.7% in 2010), p<0.001. Multivariable logistic regression analyses adjusted for patient characteristics including comorbidities, showed no survival difference between sexes in patients with a non-shockable rhythm (OR 1.00; CI 0.72-1.40), while female sex was positively associated with survival in patients with a shockable rhythm (OR 1.31; CI 1.07-1.59). Analyses were rhythm-stratified due to interaction between sex and heart rhythm; there was no interaction between sex and calendar-year. Temporal increase in crude survival was more marked in males due to poorer prognostic characteristics in females with a lower proportion of shockable rhythm. In an adjusted model, female sex was positively associated with survival in patients with a shockable rhythm. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

A Population-Based Study of Alcohol Use in Same-Sex and Different-Sex Unions

PubMed Central

Reczek, Corinne; Liu, Hui; Spiker, Russell

2014-01-01

The present study advances research on union status and health by providing a first look at alcohol use differentials among different-sex and same-sex married and cohabiting individuals using nationally representative population-based data (National Health Interview Surveys 1997–2011, N = 181,581). The results showed that both same-sex and different-sex married groups reported lower alcohol use than both same-sex and different-sex cohabiting groups. The results further revealed that same-sex and different-sex married individuals reported similar levels of alcohol use, whereas same-sex and different-sex cohabiting individuals reported similar levels of alcohol use. Drawing on marital advantage and minority stress approaches, the findings suggest that it is cohabitation status—not same-sex status—that is associated with elevated alcohol rates. PMID:24860195

Structural factors that increase HIV/STI vulnerability among indigenous people in the Peruvian amazon.

PubMed

Orellana, E Roberto; Alva, Isaac E; Cárcamo, Cesar P; García, Patricia J

2013-09-01

We examined structural factors-social, political, economic, and environmental-that increase vulnerability to HIV among indigenous people in the Peruvian Amazon. Indigenous adults belonging to 12 different ethnic groups were purposively recruited in four Amazonian river ports and 16 indigenous villages. Qualitative data revealed a complex set of structural factors that give rise to environments of risk where health is constantly challenged. Ferryboats that cross Amazonian rivers are settings where unprotected sex-including transactional sex between passengers and boat crew and commercial sex work-often take place. Population mobility and mixing also occurs in settings like the river docks, mining sites, and other resource extraction camps, where heavy drinking and unprotected sex work are common. Multilevel, combination prevention strategies that integrate empirically based interventions with indigenous knowledge are urgently needed, not only to reduce vulnerability to HIV transmission, but also to eliminate the structural determinants of indigenous people's health.

The harder they fall? Sex and race/ethnic specific suicide rates in the U.S. foreclosure crisis.

PubMed

Houle, Jason N; Light, Michael T

2017-05-01

Previous work shows suicide rates increase during economic recessions, but little research has examined the extent to which the foreclosure crisis-a unique aspect of the Great Recession-has contributed to disparities in rising suicide rates by race and sex. We develop and test two competing hypotheses regarding the association between foreclosures and race by sex specific suicide rates. We link foreclosure data (RealtyTrac) and suicide data (CDC) from 174 metropolitan areas from 2005 to 2010 (1044 MSA-year observations) and find that-net of time invariant unobserved between-metro area differences, national time trends, and time-varying confounders-a rise in the foreclosure rate is associated with a marginal increase in suicide, but this main effect masks considerable heterogeneity across groups. The association is particularly strong for white males, and weaker or non-existent for other race by sex groups. Copyright © 2017 Elsevier Ltd. All rights reserved.

Gay marriage, same-sex parenting, and America's children.

PubMed

Meezan, William; Rauch, Jonathan

2005-01-01

Same-sex marriage, barely on the political radar a decade ago, is a reality in America. How will it affect the well-being of children? Some observers worry that legalizing same-sex marriage would send the message that same-sex parenting and opposite-sex parenting are interchangeable, when in fact they may lead to different outcomes for children. To evaluate that concern, William Meezan and Jonathan Rauch review the growing body of research on how same-sex parenting affects children. After considering the methodological problems inherent in studying small, hard-to-locate populations--problems that have bedeviled this literature-the authors find that the children who have been studied are doing about as well as children normally do. What the research does not yet show is whether the children studied are typical of the general population of children raised by gay and lesbian couples. A second important question is how same-sex marriage might affect children who are already being raised by same-sex couples. Meezan and Rauch observe that marriage confers on children three types of benefits that seem likely to carry over to children in same-sex families. First, marriage may increase children's material well-being through such benefits as family leave from work and spousal health insurance eligibility. It may also help ensure financial continuity, should a spouse die or be disabled. Second, same-sex marriage may benefit children by increasing the durability and stability of their parents' relationship. Finally, marriage may bring increased social acceptance of and support for same-sex families, although those benefits might not materialize in communities that meet same-sex marriage with rejection or hostility. The authors note that the best way to ascertain the costs and benefits of the effects of same-sex marriage on children is to compare it with the alternatives. Massachusetts is marrying same-sex couples, Vermont and Connecticut are offering civil unions, and several states offer partner-benefit programs. Studying the effect of these various forms of unions on children could inform the debate over gay marriage to the benefit of all sides of the argument.

Sex differences in the effects of juvenile and adult diet on age-dependent reproductive effort.

PubMed

Houslay, T M; Hunt, J; Tinsley, M C; Bussière, L F

2015-05-01

Sexual selection should cause sex differences in patterns of resource allocation. When current and future reproductive effort trade off, variation in resource acquisition might further cause sex differences in age-dependent investment, or in sensitivity to changes in resource availability over time. However, the nature and prevalence of sex differences in age-dependent investment remain unclear. We manipulated resource acquisition at juvenile and adult stages in decorated crickets, Gryllodes sigillatus, and assessed effects on sex-specific allocation to age-dependent reproductive effort (calling in males, fecundity in females) and longevity. We predicted that the resource and time demands of egg production would result in relatively consistent female strategies across treatments, whereas male investment should depend sharply on diet. Contrary to expectations, female age-dependent reproductive effort diverged substantially across treatments, with resource-limited females showing much lower and later investment in reproduction; the highest fecundity was associated with intermediate lifespans. In contrast, long-lived males always signalled more than short-lived males, and male age-dependent reproductive effort did not depend on diet. We found consistently positive covariance between male reproductive effort and lifespan, whereas diet altered this covariance in females, revealing sex differences in the benefits of allocation to longevity. Our results support sex-specific selection on allocation patterns, but also suggest a simpler alternative: males may use social feedback to make allocation decisions and preferentially store resources as energetic reserves in its absence. Increased calling effort with age therefore could be caused by gradual resource accumulation, heightened mortality risk over time, and a lack of feedback from available mates. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

Systematic Review and Individual Patient Data Meta-Analysis of Sex Differences in Depression and Prognosis in Persons With Myocardial Infarction: A MINDMAPS Study.

PubMed

Doyle, Frank; McGee, Hannah; Conroy, Ronán; Conradi, Henk Jan; Meijer, Anna; Steeds, Richard; Sato, Hiroshi; Stewart, Donna E; Parakh, Kapil; Carney, Robert; Freedland, Kenneth; Anselmino, Matteo; Pelletier, Roxanne; Bos, Elisabeth H; de Jonge, Peter

2015-05-01

Using combined individual patient data from prospective studies, we explored sex differences in depression and prognosis post-myocardial infarction (MI) and determined whether disease indices could account for found differences. Individual patient data analysis of 10,175 MI patients who completed diagnostic interviews or depression questionnaires from 16 prospective studies from the MINDMAPS study was conducted. Multilevel logistic and Cox regression models were used to determine sex differences in prevalence of depression and sex-specific effects of depression on subsequent outcomes. Combined interview and questionnaire data from observational studies showed that 36% (635/1760) of women and 29% (1575/5526) of men reported elevated levels of depression (age-adjusted odds ratio = 0.68, 95% confidence interval [CI] = 0.60-0.77). The risk for all-cause mortality associated with depression was higher in men (hazard ratio = 1.38, 95% CI = 1.30-1.47) than in women (hazard ratio = 1.22, 95% CI = 1.14-1.31; sex by depression interaction: p < .001). Low left ventricular ejection fraction (LVEF) was associated with higher depression scores in men only (sex by LVEF interaction: B = 0.294, 95% CI = 0.090-0.498), which attenuated the sex difference in the association between depression and prognosis. The prevalence of depression post-MI was higher in women than in men, but the association between depression and cardiac prognosis was worse for men. LVEF was associated with depression in men only and accounted for the increased risk of all-cause mortality in depressed men versus women, suggesting that depression in men post-MI may, in part, reflect cardiovascular disease severity.

Soft tissue thickness values for black and coloured South African children aged 6-13 years.

PubMed

Briers, N; Briers, T M; Becker, P J; Steyn, M

2015-07-01

In children, craniofacial changes due to facial growth complicate facial approximations and require specific knowledge of soft tissue thicknesses (STT). The lack of South African juvenile STT standards of particular age groups, sex and ancestry is problematic. According to forensic artists in the South African Police Service the use of African-American values to reconstruct faces of Black South African children yields poor results. In order to perform a facial approximation that presents a true reflection of the child in question, information regarding differences in facial soft tissue at different ages, sexes and ancestry groups is needed. The aims of this study were to provide data on STT of South African Black and Coloured children and to assess differences in STT with respect to age, sex and ancestry. STT was measured using cephalograms of South African children (n=388), aged 6-13 years. After digitizing the images, STT measurements were taken at ten mid-facial landmarks from each image using the iTEM measuring program. STT comparisons between groups per age, sex and ancestry were statistically analyzed. The results showed that STT differences at lower face landmarks are more pronounced in age groups per ancestry as opposed to differences per age and sex. Generally, an increase in STT was seen between 6-10 year old groups and 11-13 year old groups, regardless of ancestry and sex, at the midphiltrum, labiale inferius, pogonion, and beneath chin landmarks. This research created a reference dataset for STT of South African children of Black and Coloured ancestry per age and sex that will be useful for facial reconstruction/approximation of juvenile remains. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

On the relation between 2D:4D and sex-dimorphic personality traits.

PubMed

Hampson, Elizabeth; Ellis, Connie L; Tenk, Christine M

2008-02-01

Several personality traits, including aggressiveness and sensation seeking, have been hypothesized to be influenced by prenatal androgen exposure, though evidence for this proposition is limited. We investigated whether individual differences in aggressiveness, sensation seeking, and several prosocial personality traits can be predicted from differences in the 2D:4D digit ratio, a putative marker of prenatal androgen activity. A total of 164 undergraduates (87 men, 77 women) completed self-report measures of physical and verbal aggression, as well as a standardized measure of sensation seeking, and five scales to assess empathy, nurturance, expressivity/femininity, instrumentality/masculinity, and assertiveness. Two sex-dimorphic tests of spatial ability also were included. Men had a lower 2D:4D ratio than women, confirming the typical sex difference in digit proportions. Significant sex differences were observed on 10 of the 11 personality scales purported to show sex differences and on both tests of spatial ability. The 2D:4D ratio was a significant predictor of scores on three of the four aggression subscales, total aggression, thrill and adventure seeking, and total sensation-seeking, in the sample as a whole and in women. In men, correlations with 2D:4D were significant only for total sensation-seeking and verbal aggression. In both sexes, lower 2D:4D ratios were associated with increased aggressiveness and sensation seeking. For the spatial tests, there was no evidence of any association with 2D:4D in either men or women. The 2D:4D digit ratio may be a valid, though weak, predictor of selective sex-dependent traits that are sensitive to testosterone.

Sex differences in the effects of maternal vitamin supplements on mortality and morbidity among children born to HIV-infected women in Tanzania

PubMed Central

Kawai, Kosuke; Msamanga, Gernard; Manji, Karim; Villamor, Eduardo; Bosch, Ronald J.; Hertzmark, Ellen; Fawzi, Wafaie W.

2011-01-01

We examined whether there are sex differences in the effect of vitamin supplements on birth outcomes, mortality, and morbidity by two years of age among children born to HIV-infected women in Tanzania. A randomized placebo-controlled trial was conducted among 959 mother-infant pairs. HIV-infected pregnant women were randomly assigned to receive a daily oral dose of one of four regimens: multivitamins (vitamins B-complex, C, and E), vitamin A plus β-carotene, multivitamins including vitamin A plus β-carotene, or placebo. Supplements were administered during pregnancy and continued after delivery. The beneficial effect of multivitamins on decreasing the risk of low birth weight was stronger among girls (RR = 0.39, 95% CI 0.22 – 0.67) compared to boys (RR = 0.81, 95% CI 0.44 – 1.49; p for interaction = 0.08). Maternal multivitamin supplements resulted in 32% reduction in mortality among girls (RR = 0.68, 95% CI 0.47 – 0.97), whereas no effect was found among boys (RR = 1.20, 95% CI 0.80 –1.78; p for interaction = 0.04). Multivitamins had beneficial effects on the overall risks of diarrhea that did not differ by sex. Vitamin A plus β-carotene alone increased the risk of HIV transmission, but had no effect on mortality, and we found no sex differences in these effects. Sex differential effects of multivitamins on mortality may be due to sex related differences in the immunological or genetic factors. More research is warranted to examine the effect of vitamins by sex and better understand biological mechanisms mediating such effects. PMID:20211040

Sex differences in the effects of maternal vitamin supplements on mortality and morbidity among children born to HIV-infected women in Tanzania.

PubMed

Kawai, Kosuke; Msamanga, Gernard; Manji, Karim; Villamor, Eduardo; Bosch, Ronald J; Hertzmark, Ellen; Fawzi, Wafaie W

2010-06-01

We examined whether there are sex differences in the effect of vitamin supplements on birth outcomes, mortality and morbidity by 2 years of age among children born to HIV-infected women in Tanzania. A randomised placebo-controlled trial was conducted among 959 mother-infant pairs. HIV-infected pregnant women were randomly assigned to receive a daily oral dose of one of four regimens: multivitamins (vitamins B-complex, C and E), vitamin A plus beta-carotene, multivitamins including vitamin A plus beta-carotene or placebo. Supplements were administered during pregnancy and continued after delivery. The beneficial effect of multivitamins on decreasing the risk of low birth weight was stronger among girls (relative risks (RR) = 0.39, 95 % CI 0.22, 0.67) than among boys (RR = 0.81, 95 % CI 0.44, 1.49; P for interaction = 0.08). Maternal multivitamin supplements resulted in 32 % reduction in mortality among girls (RR = 0.68, 95 % CI 0.47, 0.97), whereas no effect was found among boys (RR = 1.20, 95 % CI 0.80, 1.78; P for interaction = 0.04). Multivitamins had beneficial effects on the overall risks of diarrhoea that did not differ by sex. Vitamin A plus beta-carotene alone increased the risk of HIV transmission, but had no effects on mortality, and we found no sex differences in these effects. Sex differential effects of multivitamins on mortality may be due to sex-related differences in the immunological or genetic factors. More research is warranted to examine the effect of vitamins by sex and better understand biological mechanisms mediating such effects.

Fertilization rates and in vitro embryo production using sexed or non-sexed semen selected with a silane-coated silica colloid or Percoll.

PubMed

Rodríguez Villamil, P; Wei, H; Moreira, G; Caccia, M; Fernandez Taranco, M; Bó, G A

2012-07-01

The aim of this study was to evaluate sperm fertilization rates and in vitro embryo development rates for sexed and non-sexed semen selected using a silane-coated silica colloid method (Isolate) or Percoll. Frozen/thawed, sexed and unsexed semen samples from four Holstein bulls were randomly allocated to one of two different density gradient selection methods. Sperm quality (motility, concentration, morphology and membrane integrity) were evaluated and compared before and after sperm selection. Sperm motility and morphology improved (P < 0.005) after the sperm selection process with no differences between the two methods. For non-sexed semen, Percoll gradient increased the mean (± SEM) percentage of sperm recovered (57.3 ± 2.8) compared to Isolate (46.0 ± 1.8; P < 0.01). However, membrane integrity was higher after Isolate than Percoll (sexed semen: 41.0 ± 0.6 vs. 38.8 ± 0.8 and non-sexed semen 60.8 ± 1.6 vs. 58.8 ± 0.5; P < 0.05). The percentage of blastocysts produced was higher when either sexed or non-sexed semen was selected by Isolate (14.0 ± 1.0; 22.0 ± 1.1) than by Percoll (10.5 ± 1.5; 17.0 ± 2.1, respectively; P < 0.05). In summary, Isolate was a more effective method for the recovery of high quality sperm for in vitro fertilization embryo production. Copyright © 2012 Elsevier Inc. All rights reserved.

Sex Determination of Carolina Wrens (Thryothorus ludovicianus) in the Mississippi Alluvial Valley

USGS Publications Warehouse

Twedt, D.J.

2004-01-01

I identified sexual dimorphism in wing length (unflattened chord) of Carolina Wrens (Thryothorus ludovicianus) within the central Mississippi Alluvial Valley (northeast Louisiana and west-central Mississippi) and used this difference to assign a sex to captured wrens. Wrens were identified as female when wing length was less than 57.5 mm or male when wing length was greater than 58.5 mm. Verification of predicted sex was obtained from recaptures of banded individuals where sex was ascertained from the presence of a cloacal protuberance or brood patch. Correct prediction of sex was 81% for adult females and 95% for adult males. An alternative model, which categorized wrens with wing lengths of 58 and 59 mm as birds of unknown sex, increased correct prediction of females to 93% but reduced the number of individuals to which sex was assigned. These simple, predictive, wing-length-based models also correctly assigned sex for more than 88% of young (hatching-year) birds.

Diabetes mellitus and the risk of gastrointestinal cancer in women compared with men: a meta-analysis of cohort studies.

PubMed

Fang, Hong-Juan; Shan, Shao-Bo; Zhou, Yu-Hao; Zhong, Li-Yong

2018-04-16

The increasing epidemic proportions of diabetes mellitus (DM) are a major cause of premature illness and death. However, whether DM confers the same excess risk of gastrointestinal cancer for women as it does for men remains controversial. The purpose of this study was to estimate the relation between DM and gastrointestinal cancer in women compared with men after accounting for other major risk factors based on cohort studies. We performed a meta-analysis of cohort studies published through May 2017 from PubMed, Embase, and the Cochrane Library. Studies with cohort designs were stratified by sex and reported the relation between DM and esophageal cancer (EC), gastric cancer (GC), colorectal cancer (CRC), colon cancer (CC), rectal cancer (RC), hepatocellular carcinoma (HCC), or pancreatic cancer (PC) risk. The ratio of relative risk (RRR) between men and women was employed to measure the sex differences in the relation between DM and gastrointestinal cancer with a random effects model with inverse variance weighting. We included 38 cohort studies reporting data on 18,060,698 individuals. The pooled RRR indicated DM women was associated with an increased risk of GC (RRR: 1.14; 95%CI: 1.06-1.22; p < 0.001), while the risk of HCC was lower (RRR: 0.88; 95%CI: 0.79-0.99; p = 0.031) as compared with DM men. Further, there was no evidence of sex differences in the RRR between participants who had DM compared with those without DM for EC (p = 0.068), CRC (p = 0.618), and PC (p = 0.976). In addition, the pooled RRR showed a statistically significant association between DM and the risk of CC in women compared with men (RRR: 0.93; 95%CI: 0.86-1.00; p = 0.050), and there was no evidence of sex differences for RC among participants with DM compared to those without DM (p = 0.648). Finally, the sex differences of the comparison between DM and non-DM for gastrointestinal cancer risk at different sites were variable after stratification for different effect estimates. The findings of this study suggested female-to-male RRR of DM was increased for GC, while reduced for HCC and CC. However, there were no sex differences for the relation between DM and the risk of EC, CRC, PC, and RC.

Sex Differences in Cannabis Use Disorder Diagnosis Involved Hospitalizations in the United States

PubMed Central

Zhu, He; Wu, Li-Tzy

2017-01-01

Objectives: The study examined sex differences in trend and clinical characteristics of cannabis use disorder (CUD) diagnosis involved hospitalizations among adult patients. Methods: We analyzed hospitalization data from the 2007–2011 Nationwide Inpatient Samples for patients aged 18–64 years (N = 15,114,930). Descriptive statistics were used to characterize demographic variables and to compare the proportions of CUD diagnosis and comorbid patterns between male and female hospitalizations. Logistic regressions were performed to examine the association of sex and other demographic variables with CUD diagnosis. Results: During the study period, 3.3% of male and 1.5% of female hospitalizations had any-listed CUD diagnoses, and both sexes presented an upward trend in the number, rate, and proportion of CUD diagnosis. Among hospitalizations for patients aged 18–25 years, about 1 in 10 males and 1 in 20 females included a CUD diagnosis, and this proportion decreased with age strata. Mental disorders accounted for the highest proportion of CUD involved inpatient hospitalizations, and female CUD involved hospitalizations included a higher proportion of mental disorders that required hospitalized care compared with male hospitalizations (41% vs 36%). In each sex group, younger age, black race, lower household income, large metropolitan residence, non-private insurance, substance use diagnosis, and mental disorders were associated with elevated odds of having CUD diagnosis. Conclusion: The large sample of clinical hospitalization data suggest an increased trend in CUD diagnosis and sex differences in several comorbidities with CUD-involved hospital admissions. Prevention and treatment for CUD should consider sex differences in clinical comorbidities. PMID:28700366

Sex differences during humor appreciation in child-sibling pairs.

PubMed

Vrticka, Pascal; Neely, Michelle; Walter Shelly, Elizabeth; Black, Jessica M; Reiss, Allan L

2013-01-01

The developmental origin of sex differences in adult brain function is poorly understood. Elucidating neural mechanisms underlying comparable cognitive functionality in both children and adults is required to address this gap. Humor appreciation represents a particularly relevant target for such developmental research because explanatory theories apply across the life span, and underlying neurocircuitry shows sex differences in adults. As a positive mood state, humor is also of interest due to sex differences in rates of depression, a disorder afflicting twice as many women as men. In this study, we employed functional magnetic resonance imaging (fMRI) to investigate brain responses to funny versus positive (and neutral) video clips in 22 children, ages 6-13 years, including eight sibling-pairs. Our data revealed increased activity to funny clips in bilateral temporo-occipital cortex, midbrain, and amygdala in girls. Conversely, we found heightened activation to positive clips in bilateral inferior parietal lobule, fusiform gyrus, inferior frontal gyrus, amygdala, and ventromedial prefrontal cortex in boys. Many of these effects persisted when looking at sibling-pairs only. We interpret such findings as reflecting the presence of early sex divergence in reward saliency or expectation and stimulus relevance attribution. These findings are discussed in the context of evolutionary and developmental theories of humor function.

Foot strike pattern in preschool children during running: sex and shod-unshod differences.

PubMed

Latorre-Román, Pedro Á; Párraga-Montilla, Juan A; Guardia-Monteagudo, Ignacio; García-Pinillos, Felipe

2018-04-01

This study aims to determine the foot strike patterns (FSPs) and neutral support (no inversion [INV]/eversion [EVE] and no foot rotation) in preschool children, as well as to determine the influence of shod/unshod conditions and sex. A total of 1356 children aged 3-6 years (673 boys and 683 girls) participated in this study. A sagittal and frontal-plane video (240 Hz) was recorded using a high-speed camcorder to record the following variables: rearfoot strike (RFS), midfoot strike (MFS), forefoot strike (FFS), inversion/ eversion (INV/EVE) and foot rotation on initial contact. There were no between-sex significant differences in both shod and unshod conditions in RFS. In the unshod condition, there was a significant reduction (p < 0.001) of RFS prevalence in both boys (shod condition = 44.2% vs. 34.7% unshod condition) and girls (shod condition = 48.5% vs. 36.1% unshod condition). As for neutral support, there were no between-sex differences in both shod and unshod conditions or in the shod-unshod comparison. In preschool children, no between-sex differences were found in relation to prevalence of RFS and neutral support (no INV/EVE). Shod running alters FSP of running barefoot, producing a significant increase of RFS prevalence.

From swing to cane: Sex differences of EEG resting-state temporal patterns during maturation and aging.

PubMed

Tomescu, M I; Rihs, T A; Rochas, V; Hardmeier, M; Britz, J; Allali, G; Fuhr, P; Eliez, S; Michel, C M

2018-06-01

While many insights on brain development and aging have been gained by studying resting-state networks with fMRI, relating these changes to cognitive functions is limited by the temporal resolution of fMRI. In order to better grasp short-lasting and dynamically changing mental activities, an increasing number of studies utilize EEG to define resting-state networks, thereby often using the concept of EEG microstates. These are brief (around 100 ms) periods of stable scalp potential fields that are influenced by cognitive states and are sensitive to neuropsychiatric diseases. Despite the rising popularity of the EEG microstate approach, information about age changes is sparse and nothing is known about sex differences. Here we investigated age and sex related changes of the temporal dynamics of EEG microstates in 179 healthy individuals (6-87 years old, 90 females, 204-channel EEG). We show strong sex-specific changes in microstate dynamics during adolescence as well as at older age. In addition, males and females differ in the duration and occurrence of specific microstates. These results are of relevance for the comparison of studies in populations of different age and sex and for the understanding of the changes in neuropsychiatric diseases. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

How Early Hormones Shape Gender Development

PubMed Central

Berenbaum, Sheri A.; Beltz, Adriene M.

2015-01-01

Many important psychological characteristics show sex differences, and are influenced by sex hormones at different developmental periods. We focus on the role of sex hormones in early development, particularly the differential effects of prenatal androgens on aspects of gender development. Increasing evidence confirms that prenatal androgens have facilitative effects on male-typed activity interests and engagement (including child toy preferences and adult careers), and spatial abilities, but relatively minimal effects on gender identity. Recent emphasis has been directed to the psychological mechanisms underlying these effects (including sex differences in propulsive movement, and androgen effects on interest in people versus things), and neural substrates of androgen effects (including regional brain volumes, and neural responses to mental rotation, sexually arousing stimuli, emotion, and reward). Ongoing and planned work is focused on understanding the ways in which hormones act jointly with the social environment across time to produce varying trajectories of gender development, and clarifying mechanisms by which androgens affect behaviors. Such work will be facilitated by applying lessons from other species, and by expanding methodology. Understanding hormonal influences on gender development enhances knowledge of psychological development generally, and has important implications for basic and applied questions, including sex differences in psychopathology, women’s underrepresentation in science and math, and clinical care of individuals with variations in gender expression. PMID:26688827

SEX DIFFERENCES DURING HUMOR APPRECIATION IN CHILD SIBLING-PAIRS

PubMed Central

Vrticka, Pascal; Neely, Michelle; Walter, Elizabeth; Black, Jessica M.; Reiss, Allan L.

2013-01-01

The developmental origin of sex differences in adult brain function is poorly understood. Elucidating neural mechanisms underlying comparable cognitive functionality in both children and adults is required to address this gap. Humor appreciation represents a particularly relevant target for such developmental research because explanatory theories apply across the life span and underlying neurocircuitry shows sex differences in adults. As a positive mood state, humor is also of interest due to sex differences in rates of depression, a disorder afflicting twice as many women as men. In this study, we employed fMRI to investigate brain responses to funny versus positive (and neutral) video clips in 22 children ages 6 to 13 years, including 8 sibling pairs. Our data revealed increased activity to funny clips in bilateral temporo-occipital cortex, midbrain, and amygdala in girls. Conversely, we found heightened activation to positive clips in bilateral inferior parietal lobule, fusiform gyrus, inferior frontal gyrus, amygdala, and ventromedial prefrontal cortex in boys. Many of these effects persisted when looking at sibling-pairs only. We interpret such findings as reflecting the presence of early sex divergence in reward saliency / expectation and stimulus relevance attribution. These findings are discussed in the context of evolutionary and developmental theories of humor function. PMID:23672302

Sex differences in white matter alterations following repetitive subconcussive head impacts in collegiate ice hockey players.

PubMed

Sollmann, Nico; Echlin, Paul S; Schultz, Vivian; Viher, Petra V; Lyall, Amanda E; Tripodis, Yorghos; Kaufmann, David; Hartl, Elisabeth; Kinzel, Philipp; Forwell, Lorie A; Johnson, Andrew M; Skopelja, Elaine N; Lepage, Christian; Bouix, Sylvain; Pasternak, Ofer; Lin, Alexander P; Shenton, Martha E; Koerte, Inga K

2018-01-01

Repetitive subconcussive head impacts (RSHI) may lead to structural, functional, and metabolic alterations of the brain. While differences between males and females have already been suggested following a concussion, whether there are sex differences following exposure to RSHI remains unknown. The aim of this study was to identify and to characterize sex differences following exposure to RSHI. Twenty-five collegiate ice hockey players (14 males and 11 females, 20.6 ± 2.0 years), all part of the Hockey Concussion Education Project (HCEP), underwent diffusion-weighted magnetic resonance imaging (dMRI) before and after the Canadian Interuniversity Sports (CIS) ice hockey season 2011-2012 and did not experience a concussion during the season. Whole-brain tract-based spatial statistics (TBSS) were used to compare pre- and postseason imaging in both sexes for fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). Pre- and postseason neurocognitive performance were assessed by the Immediate Post-Concussion Assessment and Cognitive Test (ImPACT). Significant differences between the sexes were primarily located within the superior longitudinal fasciculus (SLF), the internal capsule (IC), and the corona radiata (CR) of the right hemisphere (RH). In significant voxel clusters (p < 0.05), decreases in FA (absolute difference pre- vs. postseason: 0.0268) and increases in MD (0.0002), AD (0.00008), and RD (0.00005) were observed in females whereas males showed no significant changes. There was no significant correlation between the change in diffusion scalar measures over the course of the season and neurocognitive performance as evidenced from postseason ImPACT scores. The results of this study suggest sex differences in structural alterations following exposure to RSHI. Future studies need to investigate further the underlying mechanisms and association with exposure and clinical outcomes.

Affective differences in Iowa Gambling Task performance associated with sexual risk taking and substance use among HIV-positive and HIV-negative men who have sex with men.

PubMed

Golub, Sarit A; Thompson, Louisa I; Kowalczyk, William J

2016-01-01

We investigated the relationship between emotional distress and decision making in sexual risk and substance use behavior among 174 (ages 25 to 50 years, 53% black) men who have sex with men (MSM), a population at increased risk for HIV. The sample was stratified by HIV status. Measures of affective decision making, depression, anxiety, sex acts, and substance use during the past 60 days were collected at our research center. Negative binomial regression models were used to examine the relationship between age, HIV status, anxiety, depression, and IGT performance in the prediction of number of risky sex acts and substance use days. Among those without anxiety or depression, both number of risky sex acts and drug use days decreased with better performance during risky trials (i.e., last two blocks) of the IGT. For those with higher rates of anxiety, but not depression, IGT risk trial performance and risky sex acts increased concomitantly. Anxiety also interacted with IGT performance across all trials to predict substance use, such that anxiety was associated with greater substance use among those with better IGT performance. The opposite was true for those with depression, but only during risk trials. HIV-positive participants reported fewer substance use days than HIV-negative participants, but there was no difference in association between behavior and IGT performance by HIV status. Our findings suggest that anxiety may exacerbate risk-taking behavior when affective decision-making ability is intact. The relationship between affective decision making and risk taking may be sensitive to different profiles of emotional distress, as well as behavioral context. Investigations of affective decision making in sexual risk taking and substance use should examine different distress profiles separately, with implications for HIV prevention efforts.