Sex Differences In Distribution Research Articles

Predictors of Low Voltage Zone and Sex Differences in Low Voltage Zone Distribution in Patients with Atrial Fibrillation.

Previous studies have revealed the left atrial (LA) low voltage zone (LVZ) are tightly linked to the recurrence of atrial fibrillation (AF). Furthermore ablation that targets the LA LVZ can improve patient prognosis. The aim of this study was to identify potential clinical predictors of the LA LVZ, to investigate possible sex differences in the distribution of LA LVZ, and to examine the relationship between LA LVZ and AF recurrence. A total of 108 patients who underwent AF catheter ablation and LA high-density electro-anatomic mapping were enrolled in the study. Of these, 56 patients with LA LVZ 5% were assigned to the LVZ group, while the remaining 52 patients with LA LVZ 5% were assigned to the non-LVZ group. Clinical characteristics and laboratory results for all patients were collected and compared between the two groups. Multivariate logistic regression analysis revealed that persistent AF (odds ratio [OR] = 4.563, 95% confidence interval [CI]: 1.194-17.431, p = 0.026), left atrial volume (LAV, OR = 1.030, 95% CI: 1.001-1.061, p = 0.044) and brain natriuretic peptide (BNP, OR = 1.010, 95% CI: 1.002-1.019, p = 0.015) were independent predictors for the presence of LA LVZ. In addition, female sex (OR = 7.161, 95% CI: 1.518-33.792, p = 0.013), LAV (OR = 1.028, 95% CI: 1.002-1.055, p = 0.035) and BNP (OR = 1.009, 95% CI: 1.001-1.016, p = 0.018) were independent predictors of severe LA LVZ (LA LVZ 20%). The extent of LVZ was significantly greater in females than in males (32.8% 15.5% vs. 23.5% 12.7%, p = 0.021), especially in the anterior (34.5% 16.7% vs. 20.0% 16.4%, p = 0.003) and septal (44.9% 17.1% vs. 29.0% 18.9%, p = 0.004) walls. During follow-up, AF recurrence was significantly higher in patients with LA LVZ than in those without LA LVZ (31.3% vs. 12.8%, respectively, p = 0.023). In this study cohort, persistent AF, LAV and BNP were independent predictors of LA LVZ. Furthermore, female sex, LAV and BNP were independent predictors of severe LA LVZ. Females had a significantly greater extent of LVZ than males, especially in the anterior and septal walls. Patients with LA LVZ had a higher risk of recurrent AF.

Association of sex-specific abdominal adipose tissue with WHO/ISUP grade in clear cell renal cell carcinoma

ObjectivesTo explore the association between computed tomography (CT)-measured sex-specific abdominal adipose tissue and the pathological grade of clear cell renal cell carcinoma (ccRCC).MethodsThis retrospective study comprised 560 patients (394 males and 166 females) with pathologically proven ccRCC (467 low- and 93 high-grade). Abdominal CT images were used to assess the adipose tissue in the subcutaneous, visceral, and intermuscular regions. Subcutaneous fat index (SFI), visceral fat index (VFI), intermuscular fat index (IFI), total fat index (TFI), and relative visceral adipose tissue (rVAT) were calculated. Univariate and multivariate logistic regression analyses were performed according to sex to identify the associations between fat-related parameters and pathological grade.ResultsIFI was significantly higher in high-grade ccRCC patients than in low-grade patients for both men and women. For male patients with high-grade tumors, the SFI, VFI, TFI, and rVAT were significantly lower, but not for female patients. In both univariate and multivariate studies, the IFI continued to be a reliable and independent predictor of high-grade ccRCC, regardless of sex.ConclusionsIntermuscular fat index proved to be a valuable biomarker for the pathological grade of ccRCC and could be used as a reliable independent predictor of high-grade ccRCC for both males and females.Critical relevance statementSex-specific fat adipose tissue can be used as a new biomarker to provide a new dimension for renal tumor-related research and may provide new perspectives for personalized tumor management decision-making approaches.Key points• There are sex differences in distribution of subcutaneous fat and visceral fat.• The SFI, VFI, TFI, and rVAT were significantly lower in high-grade ccRCC male patients, but not for female patients.• Intermuscular fat index can be used as a reliable independent predictor of high-grade ccRCC for both males and females.Graphical

Sex differences in distribution and identity of aromatase gene expressing cells in the young adult rat brain

BackgroundAromatase catalyzes the synthesis of estrogens from androgens. Knowledge on its regional expression in the brain is of relevance to the behavioral implications of these hormones that might be linked to sex differences in mental health. The present study investigated the distribution of cells expressing the aromatase coding gene (Cyp19a1) in limbic regions of young adult rats of both sexes, and characterized the cell types expressing this gene.MethodsCyp19a1 mRNA was mapped using fluorescent in situ hybridization (FISH). Co-expression with specific cell markers was assessed with double FISH; glutamatergic, gamma-aminobutyric acid (GABA)-ergic, glial, monoaminergic, as well as interneuron markers were tested. Automated quantification of the cells expressing the different genes was performed using CellProfiler. Sex differences in the number of cells expressing Cyp19a1 was tested non-parametrically, with the effect size indicated by the rank-biserial correlation. FDR correction for multiple testing was applied.ResultsIn the male brain, the highest percentage of Cyp19a1+ cells was found in the medial amygdaloid nucleus and the bed nucleus of stria terminalis, followed by the medial preoptic area, the CA2/3 fields of the hippocampus, the cortical amygdaloid nucleus and the amygdalo-hippocampal area. A lower percentage was detected in the caudate putamen, the nucleus accumbens, and the ventromedial hypothalamus. In females, the distribution of Cyp19a1+ cells was similar but at a lower percentage. In most regions, the majority of Cyp19a1+ cells were GABAergic, except for in the cortical-like regions of the amygdala where most were glutamatergic. A smaller fraction of cells co-expressed Slc1a3, suggesting expression of Cyp19a1 in astrocytes; monoaminergic markers were not co-expressed. Moreover, sex differences were detected regarding the identity of Cyp19a1+ cells.ConclusionsFemales show overall a lower number of cells expressing Cyp19a1 in the limbic brain. In both sexes, aromatase is expressed in a region-specific manner in GABAergic and glutamatergic neurons. These findings call for investigations of the relevance of sex-specific and region-dependent expression of Cyp19a1 in the limbic brain to sex differences in behavior and mental health.

Analysis of Cerebrovascular Architecture in Experimental Models of Hypertension and Chronic Neuroendocrine Stress

Cerebral small vessel disease and Alzheimer’s disease are leading causes of dementia. Psychological/social stress and associated hypertension are important drivers of brain vascular dysfunction and impaired perfusion. We set out to investigate if chronic neuroendocrine stress and hypertension have adverse effects on cerebrovascular architecture of various brain regions in two rodent models: 1) a rat model where HPA axis activation and hypertension were induced by brain derived neurotrophic factor (BDNF) overexpression in the paraventricular nucleus of the hypothalamus (PVN) for 5 wks, and 2) in a mouse model, where blood pressure and/or corticosterone levels were elevated by subcutaneous infusions of angiotensin II (AngII, 1.5mg/kg/day), adrenocorticotropic hormone (ACTH, 30ug/kg/day) or a combination of AngII and ACTH for 4 weeks. Cerebrovasculature was labeled by transcardiac perfusion of a liposome‑encapsulated fluorescent DiI dye. Brains were fixed in 4% PFA and transparency was increased with the SeeDB method. Vasculature of the hippocampus (HPC), sensory cortex (CTX), and PVN was evaluated using 2‐photon microscopy in 2mm thick coronal brain slices. 3D model of the vasculature was created by Imaris software (Oxford Instruments) yielding parameters such as vascular segment numbers, lengths, diameters, and number of branch points. 3D Euclidean distance mapping (EDM) was used to determine distribution of distances to nearest vessels (DNVs) within the extravascular space as a measure of accessibility to blood supply. We found that vascular densities were markedly elevated in the PVN relative to other brain regions in both rats and mice. In mice, HPC vascular density was significantly lower relative to CTX, whereas in rats, CTX and HPC densities were similar [vascular densities % (rats, mice): PVN:14.6±1.4, 17.0±0.6; CTX: 9.6±0.5, 8.6±0.4; HPC CA: 8.8±0.7, 6.2±0.3; HPC DG: 9.4±0.6, 5.4±0.3]. EDM analysis revealed that the proportion of short (<15μm) vs long DNVs was the highest in the PVN in both rats and mice. Distribution of DNVs shifted to longer distances in the CTX, and the proportion of short vs long DNVs was the lowest in HPC regions indicating an increased vulnerability to hypoperfusion. Interestingly, neuroendocrine stress and hypertension failed to significantly affect vascular densities and DNV statistics in either rats or mice in the analyzed brain regions. However, there was a notable sex difference in distribution of DNVs in HPC CA regions with male rats having a higher proportion of longer distances than females. In addition, analysis of vascular diameter distribution revealed that BDNF treatment decreased vessel diameters in the PVN of both male and female rats, and in the CTX of male, but not female rats. In summary, we found significant region‐specific variability in vascular structure, with the PVN demonstrating a uniquely dense vascular network. Cerebrovascular architecture was fairly resilient to treatments resembling chronic stress‐induced neuroendocrine and cardiovascular responses, but sex differences in HPC vasculature may promote a higher sensitivity to hypoperfusion in male vs female rats.

Prognostic utility of self-reported sarcopenia (SARC-F) in the Multiethnic Cohort.

BackgroundAge‐related loss in skeletal muscle mass, quality, and strength, known as sarcopenia, is a well‐known phenomenon of aging and is determined clinically using methods such as dual‐energy X‐ray absorptiometry (DXA). However, these clinical methods to measure sarcopenia are not practical for population‐based studies, and a five‐question screening tool known as SARC‐F has been validated to screen for sarcopenia.MethodsWe investigated the relationship between appendicular skeletal lean mass/height2 (ALM/HT2) (kg/m2) assessed by DXA and SARC‐F in a subset of 1538 (778 men and 760 women) participants in the Multiethnic Cohort (MEC) Study after adjustment for race/ethnicity, age, and body mass index (BMI) at the time of DXA measurement. We then investigated the association between SARC‐F and mortality among 71 283 (41 757 women and 29 526 men) participants in the MEC, who responded to the five SARC‐F questions on a mailed questionnaire as part of the MEC follow‐up in 2012–2016.ResultsIn women, SARC‐F score was significantly inversely associated with ALM/HT2 after adjusting for race/ethnicity, and age and BMI at DXA (r = −0.167, P < 0.001); the result was similar in men although it did not reach statistical significance (r = −0.056, P = 0.12). Among the 71 000+ MEC participants, SARC‐F score ≥ 4, as an indicator of sarcopenia, was higher in women (20.9%) than in men (11.2%) (P < 0.0001) and increased steadily with increasing age (6.3% in <70 vs. 41.3% in 90+ years old) (P < 0.0001). SARC‐F score ≥ 4 was highest among Latinos (30.8% in women and 16.1% in men) and lowest in Native Hawaiian women (15.6%) and Japanese American men (8.9%). During an average of 6.8 years of follow‐up, compared with men with SARC‐F score of 0–1 (indicator of no sarcopenia), men with SARC‐F 2–3 (indicator of pre‐sarcopenia) and SARC‐F ≥ 4 had significantly increased risk of all‐cause mortality [hazard ratio (HR) = 1.00, 1.77, 3.73, P < 0.001], cardiovascular disease (CVD) mortality (HR = 1.00, 1.85, 3.98, P < 0.001), and cancer mortality (HR = 1.00, 1.46, 1.96, P < 0.001) after covariate adjustment. Comparable risk association patterns with SARC‐F scores were observed in women (all‐cause mortality: HR = 1.00, 1.47, 3.10, P < 0.001; CVD mortality: HR = 1.00, 1.59, 3.54, P < 0.001; cancer mortality: HR = 1.00, 1.30, 1.77, P < 0.001). These significant risk patterns between SARC‐F and all‐cause mortality were found across all sex–race/ethnic groups considered (12 in total).ConclusionsAn indicator of sarcopenia, determined using SARC‐F, showed internal validity against DXA and displayed racial/ethnic and sex differences in distribution. SARC‐F was associated with all‐cause mortality as well as cause‐specific mortality.

Sex differences in cardiometabolic abnormalities in a middle-aged Maltese population.

There are sex differences in distribution of fat and in the prevalence of overweight and obesity. We therefore sought to explore sex differences in the prevalence of adiposity-metabolic health phenotypes, in anthropometric and cardio-metabolic parameters, and in the relationship between body mass index (BMI) categories and metabolic health. We conducted a cross-sectional study carried out between January 2018 and June 2019, of a nationally representative sample of the Maltese Caucasian population aged 41 ± 5years. Metabolic health was defined as presence of ≤ 1 parameter of the metabolic syndrome as defined by the National Cholesterol Education Program-Adult Treatment Panel III criteria. Males exhibited the unhealthy metabolic phenotype more frequently than women (41.3% vs 27.8%). In total, 10.3% of normal weight men and 6.3% of normal weight women were metabolically unhealthy. Males had a higher median BMI, but a lower proportion of males exhibited an abnormally high waist circumference as compared with females. A significant difference in sex distribution was noted for each body composition phenotype. In a contemporary sample of middle-aged individuals, males were more metabolically unhealthy and more insulin resistant than their female counterparts in spite of exhibiting an abnormal waist circumference less frequently and having similar waist index. This suggests that the currently used cut-offs for normal waist circumference should be revised downwards in men. Since even normal weight men were more often metabolically unhealthy than normal weight women, BMI cut-offs may also need to be lowered in men.

Sex differences in distribution, management and outcomes of combined ischemic-bleeding risk following acute coronary syndrome

BackgroundRisk factors for further bleeding and ischemic events after acute coronary syndrome (ACS) often overlap. Little is known about sex-based differences in the management and outcomes of ACS patients according to their combined bleeding-ischemic risk. MethodsAll ACS hospitalizations in the United Kingdom (2010–2017) were retrospectively analyzed, stratified by sex and bleeding-ischemic risk combination (using CRUSADE and GRACE scores). Multivariable logistic regression was performed to examine association between risk-groups and 1) receipt of guideline-recommended management and 2) in-hospital outcomes. ResultsOf 584,360 patients, a third of males (32.3%) and females (32.6%) were in the dual high-risk group (High CRUSADE- High GRACE). In comparison to the dual low-risk group (Low CRUSADE-Low GRACE), the dual high-risk patients of both sexes were 59–83% less likely to receive inpatient revascularisation (PCI or CABG) and 50% less likely to receive dual antiplatelet therapy (DAPT) on discharge, with a significant increase in odds of MACE (~8 to 9-fold), all-cause and cardiac mortality (25 to 35-fold), and bleeding (78–91%). The greatest difference in management and clinical outcomes between sexes was found in the dual-high risk group where females were less likely to receive guideline-recommended therapy (revascularisation and DAPT), compared to males, and were more likely to experience MACE, all-cause and cardiac mortality. ConclusionACS patients with dual high-risk for bleeding and recurrent ischemia, especially females, are less likely to receive guideline-recommended therapy and experience significantly worse outcomes. Novel strategies are needed to effectively manage this highly prevalent, complex patient group and address the under-treatment of females.

Sex differences in distribution of cannabinoid receptors (CB1 and CB2), S100A6 and CacyBP/SIP in human ageing hearts

BackgroundWomen live about 4 years longer due to lower prevalence of cardiovascular complication with ageing. However, the mechanisms involved in the preservation of heart functionality in women have not been fully elucidated.The endocannabinoid system fulfils a significant role in the regulation of cardiovascular system functioning. Cannabinoids, acting through specific receptors (CB1 and CB2), influence on blood pressure, heart rate and myocardial contractility. The function of cardiac muscle cells is strictly dependent on calcium ions. Calcium homeostasis in cardiomyocytes is subjected to complex regulation via calcium-binding proteins. Among them, increasing attention has been paid to the recently discovered S100A6 and CacyBP/SIP.In order to better understand sex differences in the regulation of cardiomyocyte function during ageing, we undertook the present research aimed at immunohistochemical identification and comparative evaluation of cannabinoid receptors, S100A6 and CacyBP/SIP, in the myocardium of ageing men and women.MethodsThe study was conducted on the hearts of 12 men and 10 women (organ donors) without a history of cardiovascular disease. The subjects were divided into two age groups: subjects older than 50 years and subjects under 50 years old. Paraffin heart sections were processed by immunohistochemistry for detection of cannabinoids receptors, S100A6 and CacyBP/SIP. In the heart samples from each study, participant’s expression of genes coding for CB1, CB2, S100A6 and CacyBP/SIP using real-time PCR method was measured.ResultsCB1 and CB2 immunoreactivity in the cytoplasm of cardiomyocytes in the heart of subjects over 50 was weaker than in younger individuals. In the heart of younger men, CB1-immunoreactivity was weaker and CB2-immunoreaction was stronger compared to women. In the hearts of older men, the CB1-immunostaining was more intense and CB2-immunoreactivity was weaker than in women. Immunodetection of CB1 shoved the presence of receptor in the intercalated discs, but only in the hearts of individuals over the 50 years old. In the hearts of older individuals, stronger immunolabelling was observed for S100A6 and CacyBP/SIP. Male hearts had greater S100A6-immunoreactivity (both age groups) but less CacyBP/SIP immunostaining (individuals over 50 years) compared to the age-matched women. The expression of genes coding CB1, CB2, S100A6 and CacyBP/SIP in the human heart was sex and age-dependent. Observed changes between men and women as well as between subject under and over 50 years were consistent with immunohistochemically stated changes in peptide content.ConclusionTogether, the data presented here indicate a close interaction between ageing and sex on the distribution and levels of cannabinoid receptors (CB1, CB2), S100A6 and CacyBP/SIP in the human heart.

The establishment and eradication of an extra-limital population of invasive cane toads

Biological invasions expand not only as a continuous front, but also via translocation of small numbers of individuals to sites far from the main distribution. Detecting and eradicating such satellite populations is critical to curtailing the invasion. Cane toads (Rhinella marina) have been spreading through Australia since 1935, and in 2010 were reported in suburban Sydney, 500 km from the main invasion. The amphibians arrived as stowaways in trucks, and bred successfully in at least 3 years. Local residents noted the toads’ presence long before management authorities. As soon as they recognised the population’s establishment, however, the authorities surveyed locations of toads, assessed toad demography, and culled toads. Radio-tracking revealed the locations of spawning sites, which were then fenced to exclude access. As a result of reproduction, growth, and sex-specific culling (due to sex differences in distribution and catchability), successive years saw major changes in toad abundance, body-size distributions and sex ratios. Rates of infection of toads by parasites (lungworms) increased through time also. Adult male toads were collected primarily from the initial introduction site, whereas adult females were collected from a broader area. A total of > 900 post-metamorphic cane toads and > 5000 earlier life stages were collected, and those efforts (plus predation by rats and birds) exterminated the population (no sightings for the past 3 years). Cane toads will continue to be translocated to sites far outside their main invaded range, but the successful eradication effort suggests that well-integrated programs, with close collaboration among stakeholders, can prevent such populations from establishing.

Sex differences in neuromuscular androgen receptor expression and sociosexual behavior in a sex changing fish.

Androgen signaling, via receptor binding, is critical for regulating the physiological and morphological foundations of male-typical reproductive behavior in vertebrates. Muscles essential for male courtship behavior and copulation are highly sensitive to androgens. Differences in the distribution and density of the androgen receptor (AR) are important for maintaining dimorphic musculature and thus may provide for anatomical identification of sexually selected traits. In Lythrypnus dalli, a bi-directional hermaphroditic teleost fish, both sexes produce agonistic approach displays, but reproductive behavior is sexually dimorphic. The male-specific courtship behavior is characterized by rapid jerky movements (involving dorsal fin erection) towards a female or around their nest. Activation of the supracarinalis muscle is involved in dorsal fin contributions to both agonistic and sociosexual behavior in other fishes, suggesting that differences in goby sexual behavior may be reflected in sexual dimorphism in AR signaling in this muscle. We examined sex differences in the local distribution of AR in supracarinalis muscle and spinal cord. Our results demonstrate that males do express more AR in the supracarinalis muscle relative to females, but there was no sex difference in the number of spinal motoneurons expressing AR. Interestingly, AR expression in the supracarinalis muscle was also related to rates of sociosexual behavior in males, providing evidence that sexual selection may influence muscle androgenic sensitivity to enhance display vigor. Sex differences in the distribution and number of cells expressing AR in the supracarinalis muscle may underlie the expression of dimorphic behaviors in L. dalli.

Seasonal Sexual Segregation by Monomorphic Sooty Shearwaters Puffinus griseus Reflects Different Reproductive Roles during the Pre-Laying Period

Tracking technology has revolutionized knowledge of seabird movements; yet, few studies have examined sex differences in distribution and behavior of small to medium-sized, sexually-monomorphic seabirds. Application of bird-borne geolocation-immersion loggers revealed seasonal segregation in the sexually-monomorphic Sooty Shearwater Puffinus griseus, mainly in the pre-laying period, when there were clear differences in reproductive roles. Shearwaters first returned to the Falkland Islands on 27 Sept±8 d; males, on average, 8 d earlier than females. Prior to egg-laying, distribution at sea, colony attendance and behaviour depended on sex. Males foraged locally over the southern Patagonian Shelf and Burdwood Bank, spending mainly single days at sea and intervening nights in the burrow. Females, who flew for more of the day during this time, foraged in more distant areas of the northern Patagonian Shelf and Argentine Basin that were deeper, warmer and relatively more productive. Attendance of females at the colony was also more variable than that of males and, overall, males were present for significantly more of the pre-laying period (38 vs. 19% of time). Sex differences were reduced following egg-laying, with males and females using similar foraging areas and making trips of similar mean duration in incubation (7.6±2.7 d) and chick-rearing (1.4±1.3 d). Congruence continued into the non-breeding period, with both sexes showing similar patterns of activity and areas of occupancy in the NW Atlantic. Thus, seasonal changes in reproductive roles influenced patterns of sexual segregation; this occurred only early in the season, when male Sooty Shearwaters foraged locally, returning regularly to the colony to defend (or maintain) the burrow or the mate, while females concentrated on building resources for egg development in distant and relatively more productive waters.

Sex‐biases in distribution and resource use at different spatial scales in a migratory shorebird

In migratory species, sexual size dimorphism can mean differing energetic requirements for males and females. Differences in the costs of migration and in the environmental conditions occurring throughout the range may therefore result in sex-biases in distribution and resource use at different spatial scales. In order to identify the scale at which sexual segregation operates, and thus the scale at which environmental changes may have sex-biased impacts, we use range-wide tracking of individually color-ringed Icelandic black-tailed godwits (Limosa limosa islandica) to quantify sexual segregation at scales ranging from the occupation of sites throughout the non-breeding range to within-site differences in distribution and resource use. Throughout the range of this migratory shorebird, there is no evidence of large-scale sex differences in distribution during the non-breeding season. However, the sexes differ in their selection of prey types and sizes, which results in small-scale sexual segregation within estuaries. The scale of sexual segregation therefore depends on the scale of variation in resource distribution, which, in this system, is primarily within estuaries. Sexual segregation in within-site distribution and resource use means that local-scale anthropogenic impacts on estuarine benthic prey communities may disproportionately affect the sexes in these migratory shorebirds.

Thirteen Dimensions of Health in Elderly Sri Lankans: Results from a National Sri Lanka Aging Survey

To explore age and sex differences in distribution of 13 health dimensions with a focus on self-rated health (SRH) and the association between SRH and other health dimensions in elderly Sri Lankans. Sri Lanka Aging Survey, a nationally representative cross-sectional survey. Community based. Inhabitants of 13 districts in Sri Lanka aged 60 and older (N=2,413). Self-reported SRH, hearing, activities of daily living (ADLs), instrumental activities of daily living (IADLs), mobility, physical disability, chronic diseases, stress and worry, mood, cognition, social participation, social support, and financial health. The prevalence of being "healthy" in most health dimensions, including SRH, declined with age. Men were more likely to report better SRH; independence in ADLs, IADLs, and mobility; absence of physical disability and chronic diseases; and good mental health. Absence of chronic diseases, independence in ADLs and IADLs, freedom from stress and worry, and absence of depression were associated with positive (excellent/very good/good) SRH. The male SRH advantage was not significant in adjusted analyses, and sex did not modify the association between SRH and other health dimensions. Several of the dimensions associated with positive SRH are to a certain extent modifiable and therefore provide a potential for improvement in SRH of elderly Sri Lankans. Differences between this study and studies from elsewhere in the associations between different health dimensions and SRH, and in how sex modifies these associations, suggest that some of the associations may depend on cultural context.

Sex Differences and Activity of the Left and Right Brain Hemispheres

The problem is reviewed of sex differences and the brain organization of the visual-spatial and verbal-cognitive functions both in adults and in the 5–15-year old children. Characteristic of men are the integral strategy of the face image recognition, specialization of the right hemisphere for visual-spatial functions, and the tonic inhibitory effect of the right hemisphere on the left one. Typical of women are the fragmented type of the image recognition, the equality of the brain hemispheres functions at the unfamiliar face recognition, and predominance of the left hemisphere by accuracy of the object localization in the visual field. It is possible that the general strategy of the recognition in women is not realized due to the right hemisphere submitted to the interfering effect of the left hemisphere. Analysis of sex differences in distribution of verbal functions shows that the capability for the verbal learning at the age of 5 years and older is higher in girls than in boys. Such capability seems to be accounted for by the superiority of the left hemisphere in girls in this type of its activity and by its earlier development and maturation. The phenomenon of semantic paralexia appearing more often in boys is accounted for by inclusion of lexical-semantic fields of the right hemisphere symmetric areas in the verbal-cognitive activity There are reasons to believe that the higher capability in girls for the verbal learning is mainly due to processes of the auditory-verbal integration within the limits of the left hemisphere, whereas this verbal ability in boys depends on the relative predominance of the interhemispheric connections.

Fuzzy Logic Simulation of the Testosterone Effect on Sex Differences in Vandenberg-Kuse Mental Rotation Scores

The relationship between testosterone level and mental rotation was modeled using a fuzzy logical simulation. The fuzzy model of men's and women's testosterone levels and MR scores mapped the input "space" of testosterone to the output "space" of mental rotation. The simulation showed that a single variable (testosterone) can produce a significant difference in output. The model typifies sex difference in distribution of mental rotation scores previously observed experimentally.

Differential distribution of Oystercatchers Haematopus ostralegus overwintering on the Wash, east England

Capsule Distribution varied with age, sex and feeding method. Aims To investigate how shorebirds are differentially distributed on their overwintering grounds. Methods We analysed age and bill measurements of Oystercatchers captured on the Wash in the 1990s. Results Oystercatchers caught on the southwest shores were more likely to be young birds and females. Birds caught on the east shore were more likely to be adults and males. Shellfish-stabbers were more common on the south and east shores and shellfish-hammerers more common on the west shore. Most mudflat-feeding birds were caught on the south shore. Conclusions Phenotypic differences mean that juvenile and female Oystercatchers tend to specialize in different diets and feeding methods than adults and males. This results in age and sex differences in distribution. Understanding differences in distribution can be critical when trying to predict the effect of environmental change on a given population.

Estrogen receptor alpha, but not beta, is expressed in the interneurons of the hippocampus in prepubertal rats: an in situ hybridization study

Estradiol is involved in the differentiation and plasticity of hippocampal neurons. In the CA1 region, estrogen treatment increases dendritic spines and synapse density on pyramidal cells. In the adult hippocampus, immunoreactivity for estrogen receptor alpha (ERα) has been reported in inhibitory interneurons, but neither in the pyramidal neurons nor in granule cells. Estrogens also mediate aspects of sexual differentiation of the hippocampus. To examine the possibility that an alteration in expression of the two types of estrogen receptors (ERα and ERβ) in the hippocampus underlies different roles of estrogen and/or ERs during development and in adult life, we applied non-isotopic, digoxigenin (dig)-labeled, in situ hybridization histochemistry (ISHH) for the both ER forms and examined the distribution pattern of their messages in serial, frontal sections over the postnatal period and in the adult. ERα mRNA expression was found scattered throughout the hippocampus especially in the hilar region of the dentate gyrus, and in the strata radiatum and pyramidale in the cornus ammonis at postnatal days (PND) 14, 21 and 35. In the hilus of the dorsal hippocampus, the density of ERα-labelled cells was greater in the rostro-medial aspect, while less in the lateral and the caudal region. In the ventral hippocampus the signals for ERα mRNA were also found in relatively high density in the hilus. No significant sex difference in distribution and intensity of the ERα mRNA positive cells were detected. The hippocampal distribution of ERα mRNA expression at PND 14 remained the same on PND 21 and 35 and in adulthood. As reported for adults, ERα mRNA signals appear to be in interneurons of the hippocampus but neither in the pyramidal cells nor in the dentate granular cells based on their size and location. In contrast to the result of ERα, no clear signals for ERβ mRNA were detected in the hippocampus across all ages examined, whereas they were clearly detected in the hypothalamus.

Yugoslav Mesolithic dental reduction.

Yugoslav Mesolithic dentition exhibits maximum mesiodistal reduction compared with contemporary European and North African groups. This reduction is not explained entirely by attrition, and may be seen as a continuation of the European Upper Paleolithic trend. Buccolingual dimension does not reduce as much. In fact, this dimension in premolars and molars is larger than in other groups. This observation also occurs in Natufians, who were grain collectors, hunters, and gatherers. The Yugoslav Mesolithic group was collecting and domesticating Cerelia as well as fishing and hunting. Linear enamel hypoplasias (LEH) indicate childhood stress through the fifth year, which corroborates previously reported incidence of rickets in this group. The central maxillary incisors and canines manifest higher degrees of LEH, but the appearance on the second molars suggest a more severe physiological disruption. Sex differences in distributions of alveolar resorption and calculus suggest differences in diet or nutritional stress. Previous reports indicate that females had higher incidence of osteomalacia. If so, female nutritional stress may explain the extreme mesiodistal reduction and minimal sexual dimorphism in this group.

Sex differences in the distribution of adipose tissue in the Djungarian hamster Phodopus sungorus

Female Djungarian hamsters ( Phodopus sungorus) have proportionately more adipose tissue in superficial depots than males of similar age and body composition. In both sexes, the proportion in superficial depots increases with increasing fatness. This species may be useful as a model for human obesity because it becomes as obese as modern humans without genetic, surgical or dietary manipulation and the sex differences in adipose tissue distribution resemble those of humans.

Gender stereotypes stem from the distribution of women and men into social roles.

According to stereotypic beliefs about the sexes, women are more communal (selfless and concerned with others) and less agentic (self-assertive and motivated to master) than men. These beliefs were hypothesized to stem from perceivers' observations of women and men in differing social roles: (a) Women are more likely than men to hold positions of lower status and authority, and (b) women are more likely than men to be homemakers and are less likely to be employed in the paid work force. Experiments 1 and 2 failed to support the hypothesis that observed sex differences in status underlie belief in female communal qualities and male agentic qualities. Experiment 3 supported the hypothesis that observed sex differences in distribution into homemaker and employee occupational roles account for these beliefs. In this experiment, subjects perceived the average woman and man stereotypically. Female and male homemakers were perceived as high in communion and low in agency. Female and male employees were perceived as low in communion and high in agency, although female employees were perceived as even more agentic than their male counterparts. Experiments 4 and 5 examined perceptions that might account for the belief that employed women are especially agentic: (a) A double burden of employment plus family responsibilities did not account for this belief, and (b) freedom of choice about being employed accounted for it reasonably well.