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PubMed2006

Suicide in the capital of Serbia and Montenegro in the period 1997-2004 - sex differences.

There are very few investigations about sex differences in suicide which include some other variables (e.g. age, profession etc). Data which concern suicide sex differences are obscure and usually are given in statistical accounts of causes of death. The aim of our study was to investigate sex differences in realized suicides within the city of Belgrade during the last eight year period. Data was taken from the index records of suicide in the city of Belgrade held at the Institute for Informatics and Statistics. We took sex as the main observed variable, and analyzed nine other variables as related to sex. Statistical analysis was done by using the crude specific rate. The variability of the rate was estimated by computing a confidence interval. The results of our study gave the profile of males and females who committed suicide in Belgrade in the period of the last eight years. Although there were significant quantitative differences, the female/male profile of completed suicides is similar, and differs only in the method of suicide: both males and females choose hanging, drowning and suffocation as the most common method of suicide, while poisoning is on the second most common method chosen by females and firearms the second most common method for males. The frequency of suicide, in both sexes, showed a tendency to decrease over the observed period (the highest suicide rate was in 2000- females 9.7, males 19.7, and the lowest in 2004- females 4.5 males 9.1). Male to female suicide rate ratio was 2 to 1. Sex differences were registered in all of the observed nine variables.

Adolescent↗
PubMed1986

Pituitary grafts modify sex differences in liver tumor formation in the rat following initiation with diethylnitrosamine and different promotion regimens.

We previously reported on sex differences in chemical hepatocarcinogenesis studied in the resistant hepatocyte model and on the effects of implantation of ectopic pituitary grafts into male rats on the early stages of liver carcinogenesis. Marked sex differences were found in the area ratio of enzyme-altered foci (mm2 foci/cm2 liver section) in sexually mature male and female Wistar rats (male greater than female). Pituitary grafts implanted one week before 2-acetylaminofluorene selection in male rats decreased the area ratio to a level near that of sham operated females. The present study was performed in order to investigate the relevance of the results in the short-term experiment in terms of hepatoma formation. To study the importance of 2-acetylaminofluorene selection as a determinant of the observed sex differences an experiment was also performed using the Pitot-model, where male and female rats were initiated with diethylnitrosamine and promotion was performed with phenobarbital. The long-term experiments in the resistant hepatocyte model showed that male rats develop hepatomas earlier than female rats and also showed a tendency towards a prolonged latency time in male rats bearing pituitary grafts. A good correspondence was thus achieved between the short-term and the long-term experiments. The rats treated according to the Pitot-model did not develop hepatomas within the experimental period. Of the rats killed at 13 months, three (out of five) male and five (out of five) female rats had hepatocyte nodules whereas, at 19 months two (out of six) male and five (out of six) female rats had developed such lesions in this model. We therefore conclude that 2-acetylaminofluorene is the factor responsible for the sex differences in the resistant hepatocyte model and that the hypothalamo-pituitary influence during 2-acetylaminofluorene selection is an important modifier of the carcinogenetic process.

2-Acetylaminofluorene↗
PubMed2004

The genetic basis for sex differences in human behaviour: role of the sex chromosomes.

The nature of the mechanisms underlying observed sex differences in human behaviour continues to be debated. This review concentrates on the thesis that genes on the sex chromosomes other than those directly controlling sex determination, and whose functions are, at least in part, independent from hormonal influences, play a significant role in determining gender differences in behaviour. To provide an adequate basis for examining this issue, the current understanding of the nature of sex determination, differences in behaviour and the influences of sex hormones are evaluated. The possible contribution to behavioural differences of those X-linked genes which escape inactivation, or which may be subjected to imprinting, is discussed. The review concludes with a summary of the genetic basis for two sexually disparate types of behaviour.

Behavior↗
PubMed1989

Sex differences in psychological burnout in teachers.

Sex differences in levels of experienced psychological burnout, and in antecedents and consequences, were examined among teachers and department heads. Male teachers reported greater burnout and less job satisfaction than did female teachers. Although male department heads scored significantly higher on psychological burnout, there were no sex differences on measures of satisfaction and emotional well-being. The findings are explained in terms of sex differences in levels of social support.

Adult↗
PubMed2002

Hemispheric specialisation, spatial activity experience, and sex differences on tests of mental rotation ability.

A sex difference in mental rotation ability is well established. Among the explanations offered for this difference are that males are more frequently right hemisphere specialised for spatial processing and that they receive more spatial processing experience because of the sex stereotyping of activities involving spatial ability that exists in Western societies. Several studies have shown that males do report more spatial activity experiences on the Spatial Activity Questionnaire of Newcombe, Bandura, and Taylor (1983) and that such experience does correlate with performances on tests of mental rotation. However, two prior lateralised tachistoscopic studies failed to show right hemisphere superiority for spatial task performance or that it was positively associated with better performances on the Vandenberg Mental Rotation Test. The tachistoscopic tasks used in these studies can be criticised on methodological grounds. The present study employed a new tachistoscopic task that showed that males were significantly more right hemisphere specialised (left visual-field superior) for the tachistoscopic task than females. Magnitudes of right hemisphere specialisation on the tachistoscopic task were positively and significantly related to mental rotation ability. Spatial activity experiences were also more common in males. Covariance and partial correlation analyses indicated that the sex difference in spatial ability was primarily due to sex differences in right hemisphere specialisation for mental rotation, while sex differences in spatial activity experiences were only secondarily involved.

Journal Article↗
PubMedDate not supplied

Rheumatoid factor induction in the mouse: sex differences and the effect of the sex steroids.

Female CBA mice produced a significantly higher plasma rheumatoid factor (RF) response to Salmonella typhosa lipopolysaccharide than did male mice. The peak level in females was observed on day 5-6 after injection and in males on day 7-8. Elevated RF levels continued to be detected more than 30 days later. A second injection of LPS, 38 days after the first, to assess the secondary response, had no more than an additive effect on plasma RF concentration, although the day of peak response was earlier by two days in both sexes. Administration of oestradiol-17 beta by Silastic implant brought forward the day of peak response by two days in both sexes although it reduced its amplitude considerably. Testosterone had little effect on the peak concentrations achieved in both sexes, but did produce a slower decay in plasma RF level. This investigation indicates that the sex hormones can influence the response to LPS, a polyclonal B cell activator. This may have implications for the sex differences seen in autoimmune diseases.

Animals↗
PubMed2006

Puberty, hormones, and sex differences in alcohol abuse and dependence.

Sex differences in patterns of drinking and rates of alcohol abuse and dependence begin to emerge during the transition from late puberty to young adulthood. Increases in pubertal hormones, including gonadal and stress hormones, are a prominent developmental feature of adolescence and could contribute to the progression of sex differences in alcohol drinking patterns during puberty. This paper reviews experimental and correlational studies of gonadal and stress-related hormone changes and their effects on alcohol drinking and other associated actions of alcohol. Mechanisms are suggested by which reproductive hormones and stress-related hormones may modulate neural circuits within the brain reward system to produce sex differences in alcohol drinking patterns and vulnerability to alcohol abuse and dependence which become apparent during the late pubertal period.

Alcoholism↗
PubMed2006

Sex differences in cortical thickness mapped in 176 healthy individuals between 7 and 87 years of age.

Findings from previous magnetic resonance imaging studies of sex differences in gray matter have been inconsistent, with some showing proportionally increased gray matter in women and some showing no differences between the sexes. Regional sex differences in gray matter thickness have not yet been mapped over the entire cortical surface in a large sample of subjects spanning the age range from early childhood to old age. We applied algorithms for cortical pattern matching and techniques for measuring cortical thickness to the structural magnetic resonance images of 176 healthy individuals between the ages of 7 and 87 years. We also mapped localized differences in brain size. Maps of sex differences in cortical thickness revealed thicker cortices in women in right inferior parietal and posterior temporal regions even without correcting for total brain volume. In these regions, the cortical mantle is up to 0.45 mm thicker, on average, in women than in men. Analysis of a subset of 18 female and 18 male subjects matched for age and brain volume confirmed the significance of thicker gray matter in temporal and parietal cortices in females, independent of brain size differences. Further analyses were conducted in the adult subjects where gender differences were evaluated using height as a covariate, and similar sex differences were observed even when body size differences between the sexes were controlled. Together, these results suggest that greater cortical thickness in posterior temporal inferior parietal regions in females relative to males are independent of differences in brain or body size. Age-by-sex interactions were not significant in the temporoparietal region, suggesting that sex differences in these regions are present from at least late childhood and then are maintained throughout life. Male brains were larger than female brains in all locations, though male enlargement was most prominent in the frontal and occipital poles, bilaterally. Given the large sample and the large range of ages studied, these results help to address controversies in the study of central nervous system sexual dimorphisms.

Adolescent↗
PubMed2002

Effect of diazepam on EEG power and coherent activity: sex differences.

Benzodiazepine-steroid interactions and sex differences in brain and circulating levels of gonadal steroids, lead to hypothesized differential effects of DZ on EEG in women and men. Coherent activity has been shown to be relevant for binding information into global percepts therefore diazepam effects on EEG correlation and sex differences were assessed in a double-blind crossover study. Healthy males (9) and females (9) received a single-dose (5 mg) of diazepam or placebo. EEG was recorded with eyes open (FP1, FP2, F3, F4, C3, C4, P3, P4, O1, O2) before and 2 h after drug administration in two counterbalanced sessions. DZ selectively increased delta and theta EEG correlation among frontal regions and decreased it between right parieto-occipital (theta) and fronto-central regions (alpha2) in addition to an increase in beta2 interhemispheric correlation in men and women. Men showed increased beta1 interhemispheric correlation, decreased alpha1 and increased beta power; women showed in addition, decreased theta and alpha2 power. theta rhythm was more sensitive to DZ in women, whereas interhemispheric correlation was more affected in men. DZ had a sexually dimorphic effect on waking EEG and a disrupting effect on coherent activity, increasing balance among frontal regions and decreasing temporal coupling between anterior-posterior regions. These sex differences might be related to differences in brain organization and activational effects of female gonadal steroids which are higher in women than in men.

Adult↗
PubMed2000

Sex differences in the association of endogenous sex hormone levels and glucose tolerance status in older men and women.

OBJECTIVE: Some evidence suggests an inverse association between type 2 diabetes and androgens in men and a positive association between type 2 diabetes and androgens in women. The purpose of this community-based study was to evaluate sex differences in the association between endogenous total and bioavailable estrogen and testosterone levels and glucose tolerance status. RESEARCH DESIGN AND METHODS: We included in this study 775 men and 633 postmenopausal non-estrogen-using women, all > or =55 years of age (mean ages 72 and 75 years, respectively). A 75-g oral glucose tolerance test (OGTT) was administered to fasting subjects from 1984 to 1987, when sera were frozen for measurement of total and bioavailable hormone levels. Total testosterone and estradiol levels were measured by radioimmunoassay, and bioavailable hormone levels were determined using a modified ammonium-sulfate precipitation method. The association between steroid hormones and glucose tolerance status was tested. RESULTS: In sex-specific age- and BMI-adjusted analyses, men with impaired glucose tolerance (IGT) had significantly lower total testosterone levels. Women with IGT or type 2 diabetes had significantly higher bioavailable testosterone and total and bioavailable estradiol levels than those with normal glucose tolerance. Total testosterone and fasting plasma glucose were inversely associated in men (P = 0.0001), whereas bioavailable testosterone and estradiol were positively associated with fasting plasma glucose in women (P = 0.0001 and 0.001, respectively). CONCLUSIONS: Additional studies are needed to further develop the hormone-diabetes connection.

Aged↗
PubMed1984

Sex differences in mortality.

"Patterns of sex differences in mortality in developed and developing countries are briefly described, and the range of explanatory approaches that have been used to account for these differences are reviewed. Attention is primarily focused on the higher male than female mortality rate in developed countries. Biological and behavioral/environmental perspectives on these differences are considered in some detail. It is concluded that a specifically sociological approach to sex differences in mortality requires both greater attention to the spectrum of variation within and across societies and a more complex model of causality that takes account of gender differences in the nature of mortality risks."

Behavior↗
PubMed1998

Sex differences in spontaneous locomotor activity and rotational behavior in meadow voles.

Sex differences in rotational behavior have been most clearly established in laboratory rats with females exhibiting a turning bias. Here, using an automated open-field apparatus, locomotor activity and spontaneous rotational behavior were examined in diurnally crepuscularly active reproductive male and female meadow voles (Microtus pennsylvanicus). Meadow voles, being induced ovulators, permitted analysis of females in constant behavioral estrous. Males displayed significantly greater levels of activity and also significantly greater levels of clockwise but not counterclockwise rotational behavior relative to the females. Rotational behavior was less strongly related to activity levels in female as compared to male voles. In addition, females displayed an overall turning bias. These results contrast with findings from laboratory rats in which females are reported to display greater levels of both locomotor activity and rotational behavior. They are, however, consistent with the rotational bias evident in female rats. The present findings confirm the presence of sex differences in rotational behavior and indicate that factors other than activity levels are involved in the generation and/or expression of these sex differences. Sex differences in anxiety and routine-like behavior (i.e., asymmetry in movement) are discussed as possible factors contributing to these male-female differences in rotational behavior.

Animals↗
PubMed1993

Sex differences in EEG coherence in normal children.

The idea that sex differences in the execution of different mental tasks mean a different cerebral organization met contradictory results. Sex differences in brain electrical activity were reported by various authors. The EEG coherences show functional and anatomical interrelation, so they may reveal differences in brain organization. This paper tries to demonstrate how sex differences are manifested in EEG coherences, in 42 right-handed control children, 18 girls and 24 boys, aged 7.6 to 13.3. Since the effect of age is high on EEG measurements, regression against age was calculated and eliminated. The Z-transformed coherence values were compared by Student's t-test. The results obtained showed that girls had higher right intrahemispheric coherence values than boys in all bands. These sex differences were more numerous in the theta band. The interhemispheric differences were slight and girls had higher coherences in all bands except for the alpha band, where boys had higher interhemispheric coherence than girls. These results show slight but consistent differences in the functional organization of the right hemisphere by sex and reveal the necessity to elaborate separated EEG norms for boys and girls.

Adolescent↗
PubMed2006

Sex differences in striatal dopamine release in healthy adults.

BACKGROUND: Sex differences in addictive disorders have been described. Preclinical studies have implicated the striatal dopamine system in these differences, but human studies have yet to substantiate these findings. METHODS: Using positron emission tomography (PET) scans with high-specific-activity [11C] raclopride and a reference tissue approach, we compared baseline striatal dopamine binding potential (BP) and dopamine release in men and women following amphetamine and placebo challenges. Subjective drug effects and plasma cortisol and growth hormone responses were also examined. RESULTS: Although there was no sex difference in baseline BP, men had markedly greater dopamine release than women in the ventral striatum. Secondary analyses indicated that men also had greater dopamine release in three of four additional striatal regions. Paralleling the PET findings, men's ratings of the positive effects of amphetamine were greater than women's. We found no sex difference in neuroendocrine hormone responses. CONCLUSIONS: We report for the first time a sex difference in dopamine release in humans. The robust dopamine release in men could account for increased vulnerability to stimulant use disorders and methamphetamine toxicity. Our findings indicate that future studies should control for sex and may have implications for the interpretation of sex differences in other illnesses involving the striatum.

Adult↗
PubMed1987

Regional sex differences in progestin receptor induction in the rat hypothalamus: effects of various doses of estradiol benzoate.

In the rat, sex differences in behavioral responsiveness to progesterone have been correlated with a sex difference in estrogen-induced progestin receptor induction in the ventromedial nucleus (VMN). It has recently been suggested that this sex difference in progestin receptor induction may only be present after treatment with large doses of estrogen. We have evaluated the sex difference in hypothalamic cytosol progestin receptor induction in gonadectomized/adrenalectomized rats treated with moderate doses of estradiol benzoate (EB; 20 micrograms/kg body weight). No sex differences were detected in cytosol progestin binding in mediobasal hypothalamus or preoptic area of animals treated with this dose 48 hr before they were killed. However, a higher level of progestin binding in the VMN of females than of males was found when these brain regions were examined using a microdissection technique. Saturation binding analysis of progestin binding in the VMN indicated that this sex difference in binding reflects a difference in the number of progestin binding sites, and not a difference in binding affinity. A dose-response study of progestin receptor induction in the medial preoptic nucleus (mPON), arcuate-median eminence region (ARC-ME), and VMN of male and female rats indicated a sex difference in cytosol progestin binding in the VMN at all EB doses tested (2, 8, 40, or 200 micrograms/kg body weight). No sex differences in cytosol progestin binding in the mPON or ARC-ME were observed at any of the tested doses. These results support the idea that the differences in behavioral sensitivity to progesterone may result in part from sex differences in the estrogen induction of progestin receptors in the VMN.

Animals↗
PubMed1994

Sex differences in the volume of avian song control nuclei: comparative studies and the issue of brain nucleus delineation.

Two goals of research on neural sex differences are to establish the behavioral function of such sex differences and to identify precisely what features differ between males and females. Comparative studies of sex differences in the volume of brain nuclei within the songbird vocal control circuit provide one way to address these goals. Informative comparisons can be either inter-specific or intra-specific. Inter-specific comparisons of species within the songbird suborder allow one to establish how species variation in the degree to which there is a sex difference in nuclear volume relates to species variation in the degree to which there is a sex difference in vocal behavior. Intraspecific comparisons of sex differences in nuclear volume involve the comparison of a variety of histochemical methods to define nuclei and describe a nucleus within a species. Sex differences in nuclear volume have now been measured for at least some song control nuclei in 10 different passerine species. In species with more complex male than female song, the volume of key song control nuclei is on average larger in males than in females. However, future studies will require more refined measures of vocal behavior and perceptual abilities to make more precise correlations between brain and behavior. In European starlings (Sturnus vulgaris), the volume of the vocal control nucleus, area X was found to be on average 1.95 times bigger in males than in females based on Nissl stained sections. Variation in neurotransmitter receptor density as determined by quantitative receptor autoradiography can also be used to define clearly the boundaries of a nucleus. When the boundaries of area X in male and female starlings were defined based on variation in muscarinic cholinergic and alpha 2-adrenergic receptor densities, volumetric estimates were obtained that are nearly identical to those obtained with the use of Nissl stains. Intra-specific comparisons of this sort extend our knowledge concerning the neurochemical basis of sex differences in nuclear volume. The wide application of this method would greatly increase our understanding of neural sex differences.

Animals↗
PubMed1991

Sex differences in spatial ability in children.

There is considerable evidence that sex differences in spatial ability exist in adults, with males outperforming females at every age after puberty. It is difficult, however, to find sex differences in children younger than 13. This is due in part to the lack of adequate measures of spatial ability for use with children. We report the use of spatial tests for children that are similar to those that have shown large sex differences in adults and may be measuring ability comparable to adult spatial ability. Four tests of mental rotation and spatial visualization were given to two samples of children. The first sample consisted of 81 children (39 males and 42 females) aged 9 to 12 years. The second sample consisted of 42 children (21 males and 21 females) aged 9 to 13 years. Sex differences of .4-.6 standard deviations were found on three tests in both samples. These results indicate that sex differences in spatial ability can be found in preadolescents if appropriate tests are used. Measurement of these abilities in children facilitates the investigation of possible biological and sociocultural contributors to the sex differences in spatial ability.

Aptitude↗
PubMed2000

Sex differences in response to lithium treatment.

OBJECTIVE: Although sex differences occur with some psychotropic drug treatments, they are not well defined for mood-stabilizing agents, including lithium. The authors' goal was to investigate whether there are differences between the sexes in response to lithium. METHOD: Studies identified in a literature search were analyzed for reports of sex differences in clinical response to lithium in major affective syndromes. RESULTS: Data from 17 studies published in 1967-1998, involving 1,548 adults treated with lithium for a mean of 38.6 months (SD=30.5), yielded similar weighted response rates to lithium in 1,043 women (65.6% [N=684]) and 505 men (61.0% [N=308]). CONCLUSIONS: The results indicate little difference between the sexes in clinical response to lithium treatment of bipolar and related affective disorders.

Adult↗