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Background. It is commonly assumed that there is no difference in iron status between male and female infants, despite a lack of studies addressing this question. Objective. To study sex differences in different measures of iron status in infants. Methods. At 4 months of age, 263 term, breastfed infants (121 Swedish and 142 Honduran) were randomized to receive iron supplements or placebo until 9 months of age. Blood samples at 4, 6, and 9 months of age were analyzed for hemoglobin (Hb), mean cell volume (MCV), zinc protoporphyrin (ZPP), plasma ferritin, and transferrin receptors (TfR). Results. At 4, 6, and 9 months, boys had significantly lower Hb, MCV, and ferritin and higher ZPP and TfR than girls. At 9 months, boys had a 10-fold higher risk of being classified as having iron deficiency anemia. The differences at 9 months in MCV (71.6 vs 75.1 fL) and ZPP (59 vs 49 [micro] mol/mol heme) remained significant after controlling for iron supplementation, site, growth variables, and other possible confounders. For ferritin, there was a remaining sex difference at 9 months among Swedish (29 vs 53 [micro] g/L) but not Honduran infants. For Hb and TfR, sex differences at 9 months were larger in unsupplemented infants, especially in those with a birth weight of Conclusions. There are substantial sex differences in Hb and other indicators of iron status during infancy. Some of these may be genetically determined, whereas others seem to reflect an increased incidence of true iron deficiency in boys. Pediatrics 2002;110:545-552; sex differences, gender, hemoglobin, MCV, ferritin, transferrin receptors, zinc protoporphyrin, breastfeeding, human infant, iron deficiency anemia., ABBREVIATIONS. Hb, hemoglobin; MCV, mean cell volume; ZPP, zinc protoporphyrin; TfR, transferrin receptors. It is well known that there are differences in iron status between males and females in adolescence [...]

This article compares the relationships between muscle power, peak torque patterns, and mechanomyographic and electromyographic measurements among men and women.

In a unique reversal of function, the ubiquitous and dominant inhibitory neurotransmitter, GABA, serves as the major source of neuronal excitation in the developing brain. Opening of voltage-gated [Ca.sup.2+] channels following [GABA.sub.A]-receptor-mediated depolarization translates the action of GABA into trophic responses, such as changes in cell death and synaptic patterning. During a perinatal sensitive period, steroid hormones, in particular estradiol, modulate these cellular responses to differentiate male and female brains. Profound sex differences are found in the volumes of specific nuclei, and the frequencies and types of synapses, in estradiol-concentrating brain regions. Recent evidence suggests that the mechanism of estradiol action involves enhancing, and extending the duration of, the developmental excitatory effects of GABA, resulting in divergence of the signal transduction pathways activated in males versus females. This is the first identification of a pivotal point in brain development that dictates the sex differences evident in adult physiology and behavior.

We tested the hypothesis that a single bout of dynamic exercise produces a postexercise hypotension (PEH) and [[alpha].sub.1]-adrenergic receptor hyporesponsiveness in spontaneously hypertensive rats (SHR). The postexercise [[alpha].sub.1]-adrenergic receptor hyporesponsiveness is due to an enhanced buffering of vasoconstriction by nitric oxide. Male (n = 8) and female (n = 5) SHR were instrumented with a Doppler ultrasonic flow probe around the femoral artery. Distal to the flow probe, a microrenathane catheter was inserted into a branch of the femoral artery for the infusion of the [[alpha].sub.1]-adrenergic receptor agonist phenylephrine (PE). A microrenathane catheter was inserted into the descending aorta via the left common carotid artery for measurements of arterial pressure (AP) and heart rate. Dose-response curves to PE (3.8 x [10.sub.-3] - 1.98 x [10.sub.-2][micro]g/kHz) were generated before and after a single bout of dynamic exercise. Postexercise AP was reduced in male (13 [+ or -] 3 mmHg) and female SHR (18 [+ or -] 7 mmHg). Postexercise vasoconstrictor responses to PE were reduced in males due to an enhanced influence of nitric oxide. However, in females, postexercise vasoconstrictor responses to PE were not altered. Results suggest that nitric oxidemediated [[alpha].sub.1]-adrenergic receptor hyporesponsiveness contributes to PEH in male but not female SHR. vascular function; gender; arterial pressure; adrenergic receptors

Striking sex difference was detected in the expression of estrogen receptor (ER) [beta] mRNA and protein by nonisotopic in situ hybridization and immunohistochemistry in the anteroventral periventricular nucleus (AVPV) of the rat preoptic area. In females more than in males, a significantly larger number of ER [beta] mRNA-positive cells were visualized in the medial-most portion of the AVPV within 50 [micro]m from the ependymal lining of the third ventricle. Rats of 7, 14, 21, 35, and 60 days of age (d 1 = day of birth) showed the sex difference. Orchidectomy of male neonates or estrogen treatment of female pups reversed the brain phenotype when examined on d 14. In the AVPV of adult females, ER [alpha] immunoreactivity colocalized in 83% of ER [beta] mRNA-positive cells. Tyrosine hydroxylase immunoreactivity colocalized in 18% of ER [beta] immunoreactive cells in d 21 females. Infusion of an ER [beta] antisense oligonucleotide into the third ventricle in the vicinity of the AVPV resulted in significantly longer days of successive estrus and a 50% reduction in the number of ER [beta]-immunoreactive cells in the AVPV. These findings provide support for the hypothesis that activation of ER [beta] in the AVPV is an important regulatory event in the female-typical induction of luteinizing hormone surge by estrogen.

Growth hormone (GH) secretion, controlled principally by a GH-releasing hormone (GHRH) and GH release-inhibiting hormone [somatostatin (SRIF)] displays vivid sexual dimorphism in many species. We hypothesized that relatively small differences within a dynamic core GH network driven by regulatory interactions among GH, GHRH, and SRIF explain the gender contrast. To investigate this notion, we implemented a minimal biomathematical model based on two coupled oscillators: time-delayed reciprocal interactions between GH and GHRH, which endow high-frequency (40-60 min) GH oscillations, and time-lagged bidirectional GH-SRIF interactions, which mediate low-frequency (occurring every 3.3 h) GH volleys. We show that this basic formulation, sufficient to explain GH dynamics in the male rat [Farhy LS, Straume M, Johnson ML, Kovatchev BP, and Veldhuis JD. Am J Physiol Regulatory Integrative Comp Physiol 281: R38-R51, 2001], emulates the female pattern of GH release, if autofeedback of GH on SRIF is relaxed. Relief of GH-stimulated SRIF release damps the slower volleylike oscillator, allowing emergence of the underlying high-frequency oscillations that are sustained by the GH-GHRH interactions. Concurrently, increasing variability of basal somatostatin outflow introduces quantifiable, sex-specific disorderliness of the release process typical of female GH dynamics. Accordingly, modulation of GH autofeedback on SRIF within the interactive GH-GHRH-SRIF ensemble and heightened basal SRIF variability are sufficient to transform the well-ordered, 3.3-h-interval, multiphasic, volleylike male GH pattern into a femalelike profile with irregular pulses of higher frequency. somatostatin; growth hormone-releasing hormone; hypothalamus; mathematical model; male; female; gender; somatotropic axis

Gender differences in substrate utilization during submaximal exercise in endurance-trained subjects. Am J Physiol Endocrinol Metab 282: E435-E447, 2002; 10.1152/ajpendo.00266.2001.--Substrate utilization across the leg during 90 min of bicycle exercise at 58% of peak oxygen uptake (V[O.sup.2 peak]) was studied in seven endurance-trained males and seven endurance-trained, eumenorrheic females by applying arteriovenous catheterization, stable isotopes, and muscle biopsies. The female and male groups were matched according to V[O.sup.2 peak] per kilogram of lean body mass, physical activity level, and training history of the subjects. All subjects consumed the same diet, well controlled in terms of nutrient composition as well as energy content, for 8 days preceding the experiment, and all females were tested in the midfollicular phase of the menstrual cycle. During exercise, respiratory exchange ratio (RER) and leg respiratory quotient (RQ) were similar in females and males. Myocellular triacylglycerol (TG) degradation was negligible in males but amounted to 12.4 [+ or -] 3.2 mmol/kg dry wt in females and corresponded to 25.0 [+ or -] 6.0 and 5.0 [+ or -] 7.3% of total oxygen uptake in females and males, respectively (P < 0.05). Utilization of plasma fatty acids (12.0 [+ or -] 2.5 and 9.6 [+ or -] 1.5%), blood glucose (13.6 [+ or -] 1.5 and 14.3 [+ or -] 1.5%), and glycogen (48.5 [+ or -] 4.9 and 42.8 [+ or -] 2.1%) were similar in females and males. Thus, in females, measured substrate oxidation accounted for 99% of the leg oxygen uptake, whereas in males 28% of leg oxygen uptake was unaccounted for in terms of measured oxidized lipid substrates. These findings may indicate that males utilized additional lipid sources, presumably very low density lipoprotein-TG or TG located between muscle fibers. On the basis of RER and leg RQ, it is concluded that no gender difference existed in the relative contribution from carbohydrate and lipids to the oxidative metabolism across the leg during submaximal exercise at the same relative workload. However, an effect of gender appears to occur in the utilization of the different lipid sources. [[sup.13]C]palmitate; plasma fatty acids; myocellular triacylglycerol; glucose; glycogen

In humans, as in nonhuman primates, the digits of the hands are similar in length during early fetal development. Subsequently, differentiation leads to a patter of unequal finger lengths, described by George as the finger-length pattern. Recent work by Manning and colleagues suggested that digit length patterns are due to early influences of sex hormones. Most importantly for psychology, such patterns might also relate to cognitive activities that are influenced by early organizing actions of sex hormones. The exciting possibility of having an easily measurable indicator of early action of sex hormones that relates to behavior led us to examine the universality of digit length patterns. With samples from Brazil, Canada, India, Turkey, and Korea, we showed that patterns of distal extent of finger tips are similar across different human populations. Consistent sex differences were found across the samples, showing that the index finger in males extends less far distally relative to the middle finger than is the case for females and that the difference in distal extent between index and ring fingers, relative to the middle finger, is smaller in females than in males.

This article discusses the physiological aspects of anxiety on frontal brain activity in preschool children . Topics include sex differences, depression, child psychiatry, and developmental neurology.

Kern, Mark K., Safwan Jaradeh, Ronald C. Arndorfer, Andrzej Jesmanowicz, James Hyde, and Reza Shaker. Gender differences in cortical representation of rectal distension in healthy humans. Am J Physiol Gastrointest Liver Physiol 281: G1512--G1523, 2001.--Cerebral cortical processing of information relayed via visceral afferents is poorly understood. We determined and compared cortical activity caused by various levels of rectal distension in healthy male and female subjects. Twenty-eight healthy, young (20--44 yr) volunteer subjects (13 male, 15 female) were studied with a paradigm-driven functional magnetic resonance imaging (fMRI) technique during barostat-controlled rectal distension at perception threshold and 10 mmHg below and above perception threshold. Male subjects showed localized clusters of fMRI activity primarily in the sensory and parietooccipital regions, whereas female subjects also showed activity in the anterior cingulate and insular regions. A progressive increase in maximum percent fMRI signal change and total volume of cortical activity was associated with the intensity of rectal distension pressure in both genders. Regions of cortical activity for below-threshold stimuli showed less substantial signal intensity and volume than responses for threshold and above-threshold stimuli. Volume of cortical activity during rectal distension in women was significantly higher than that for men for all distensions. We conclude that 1) there are substantial differences in female cortical activation topography during rectal distension compared with males; 2) intensity and volume of registered cortical activity due to rectal stimulation are directly related to stimulus strength; and 3) rectal stimulation below perception level is registered in the cerebral cortex. functional magnetic resonance imaging; visceral sensation; regional cortical activity Received 27 March 2001; accepted in final form 1 September 2001

15 male and 13 female soldiers participated in a study to examine the effects of sex, rifle stock length (17.8 cm, 22.3 cm, and 26.2 cm), and rifle weight (3.2 kg vs 3.8 kg) on military marksmanship performance. The Noptel simulator was used to assess marksmanship accuracy (proximity of shots to the target center) and precision (proximity of shots to one another regardless of proximity to the target center). There were no significant differences in either measure of marksmanship performance as a function of sex. Marksmanship accuracy was significantly better with the shortest rifle stock, and marksmanship precision was significantly better with the lighter rifle. Regardless of the sex of the shooter, stock length and weapon weight should be considered in any new combat rifle design as these results indicate they significantly affect marksmanship.

This article uses a hematological index to examine the incidence of iron deficiency in a sample of athletes. Findings indicate that the transferrin receptor-ferritin index is a useful tool in evaluating iron status and that iron deficiency is more prevalent and profound among women athletes.

This article investigates the relationship between sexual maturity and blood pressure levels in male and female adolescents. Findings indicate that blood pressure measures were higher among sexually mature participants and that advanced sexual maturity for age is related to higher systolic blood pressure in both groups.

This article examines the relationship between physical activity, potassium intake, and the loss of actively metabolizing cells in an elderly sample. Findings indicate that body cell mass is significantly correlated with physical activity levels in both men and women but is not associated with dietary potassium intake.

This article examines the ergogenic effects of creatine monohydrate on athletic performance during intense exercise. Findings indicate that creatine monohydrate supplementation results in improved anaerobic cycling power, greater muscle lactate concentrations, and increased muscle contraction strength for both male and female athletes.

This article examines the effects of stress on the placental transfer of Immunoglobulin G in squirrel monkeys. Results indicate that mothers who experienced chronic disturbances gave birth to male infants with lower levels of Immunoglobulin G while female infants had significantly elevated levels of the maternal antibody.

Research is presented on the onset of growth spurt among adolescent Japanese based on data accumulated since 1915. Timing of maximum growth has decreased for both sexes, with the onset for growth spurts among boys decreasing and for girls remaining mostly constant, occurring generally between 6 and 8 years of age.

Research on the growth factors for males and females is measured using schoolchildren between the ages of 7 and 14 in Jena, Germany. Sex difference plays little role in indexes during childhood, however marked differences did occur during adolescent growth spurts when females developed broader hips and shorter legs than the males.

Research on the sex-specific relationships between physical fitness and body fatness is presented, with an examination of the effect of physical fitness on these relationships. For this study, body fatness was negatively related to physical fitness and physical activity was positively related to physical fitness; this relationship is evaluated in order to prevent lifestyle-related diseases.

Modern lifestyle changes may result in site-specific alterations in the skeleton. Our aim was to determine sex and age differences in regional geometry at the mid-femur. Complete cross sections from 113 individuals aged 20-97 years from a modern Australian population were obtained. A further subsample of 24, in whom the precise orientation of specimens was known, was subsequently collected. Microradiographs were made of 100-(mu)m sections and the bone was analyzed using image processing software (Optimas, Media Cybernetics). The periosteal boundary was extracted automatically and the centroid of the periosteal outline was calculated. Fourier shape analysis was used to delineate the endocortical surface. Radial and cortical widths in each quadrant were determined. The posterior was identified by the linea aspera, and the medial and lateral were indistinguishable and therefore grouped together. For analysis, the entire sample was divided into three groups: young (20-40 years), middle (41-60 years), and old (61+ years). Raw and height-normalized values were analyzed with SPSS using t-tests, analysis of variance, and Tukey's honestly significant difference (HSD) tests. The results show that with age the femoral mid-shaft in both sexes becomes larger and more circular, with a slight shift towards the anterior. Apposition is least on the posterior and resorption greatest on the anterior, the latter being particularly evident in postmenopausal females. The greatest sex differences are seen in the middle years, lessening again in the old. We conclude that differential circumferential modeling in response to functional and postural changes occurs in both sexes with age.

Loth and Henneberg ([1996] Am J Phys Anthropol 99:473485) assert that they have discovered a single morphologic indicator of sexual dimorphism in the human mandible that rivals the predictive accuracy of the complete pelvis at 94.2% for all samples (99% for healthy samples). To test the accuracy of their method, mandibles (n = 150) from the Tepe Hissar collection were assessed for the presence or absence of mandibular ramus flexure. These results were then compared to a separate sex assessment based on morphologic indicators from the corresponding skull and innominates (where possible) to yield an overall accuracy of only 78.2%. As a means of independent assessment, the mandibular results were also compared with Krogman's ([1940] Racial Types from Tepe Hessar, Iran, from late fifth to early second millennium, BC. Amsterdam: Koninkliijke Nederlandsche Akademie van Wetenschappen) assessment of sex based on craniofacial measurements and morphologic indicators from the skull. This comparison produced an even lower accuracy of 67.2%. Such results question the predictive potential of mandibular ramus flexure as a single indicator of sexual dimorphism and suggest caution when applying this method, especially in the case of fragmentary forensic and fossil remains. KEY WORDS: sex assessment; interpopulational variation; Tepe Hissar

Real-time compression of skinfolds has been measured at three sites to evaluate dynamic compression of skinfolds and to suggest a mechanical model of compression that will give quantification of the elasticity and viscosity of the modeled tissues using generation of coeffcients for each component. A skinfold caliper with an added potentiometer was used. Subjects, eight males and eight females, were aged 18-40. After the initial rapid lowering in skinfold thickness an extended plateau phase exists and it has been attributed to relaignment of skin/tissue fibers. It may be the basis of reported skinfold compressibility sex differences.

In the present study, the motions of the different postural joints involved in reaching tasks starting from an upright posture were examined and the influence of gender on the movement pattern used was determined. Specifically, motion about the ankle, knee, and hip joints as well as angular motion of the thoracic segment with respect to the sacrum (lumbar motion) were measured. Ten healthy subjects (5 men, 5 women) reached for targets at 2 locations normalized to the subject's trunk length, arm length, and hip height. To reach each target, subjects had to bend the trunk forward. Joint motion was measured with a Selspot motion analysis system. The change in joint angle (measured in the sagittal plane from an upright standing position to the final posture adopted at target contact) was calculated for each joint. In addition, the ratio of the changes in joint angle of the lumbar spine and the hip (spine/hip ratio) was determined. Compared with female subjects, male subjects exhibited, on average, greater rotation about the lumbar spine and less rotation about the hips and knees. The spine/hip ratios for men and women were dramatically different. Men had, on average, a spine/hip ratio of 1.20 and women an average of 0.20. Those data reveal that 2 vastly different movement patterns are employed during reaching tasks that necessitate some forward bending of the trunk. Men tend to flex equally about the hips and spine, with minimal flexion about the knees, whereas women flex primarily about the hips and knees, with minimal flexion about the spine. Thus, the kinematic redundancy is resolved differently depending on gender., Gender plays a role in the motion of postural joints used in reaching tasks. Men and women generally use different techniques when bending the trunk to reach forward. Men flex at the hips and spine equally, whereas women flex the hips and knees. Men showed greater rotation than women around the lumbar spine area. Women showed greater rotation from the hips and knee joints., Key words: gender, hip, kinematic redundancy, reaching, spine There are clear differences in motor performance between men and women for tasks that require maximal effort of large muscle groups, such [...]

The purpose of this study was to re-examine the influence of gender on nasal coarticulation in normal speakers. Twenty adult speakers (10 men, 10 women) produced the vowel-nasal-vowel (VNV) sequence /ini/ within a carrier phrase using two stress patterns: (1) with equal stress placed on both syllables, and (2) with contrastive stress placed on the second syllable. A partitioned, circumferentially vented pneumotachograph mask and microphone were used to determine nasal airflow, ratios of nasal to oral-plus-nasal airflow, and sound pressure levels (SPLs) at the midpoints of the first and second vowels of the syllables. Volume ratios of nasal to oral-plus-nasal airflow that reflected the entire duration of the vowels were also obtained. Results indicated that all speakers except 1 woman exhibited nasal airflow at the midpoint of the first vowel when /ini/ was produced with equal stress; all speakers exhibited carryover nasal airflow during the second vowel. During contrastive stress, all speakers except 1 woman and 1 additional man exhibited anticipatory nasal airflow; all speakers exhibited carryover nasal airflow. Analysis of variance (ANOVA) procedures with repeated measures indicated significant main effects of syllable stress (p < 0.001) relative to nasal airflow and ratios of nasal to oral-plus-nasal airflow. Regardless of the gender of the speakers, syllable stress resulted in reduced anticipatory and carryover nasal airflow during the first and second vowels of /ini/, respectively. The results suggest that (a) both men and women adhere to similar patterns of velar articulation, and (b) velopharyngeal closure during the vowel /i/ may be enhanced during stressed syllables. Implications relative to aspects of speech production and clinical practice are discussed. KEY WORDS: nasal airflow, anticipatory coarticulation, velopharyngeal function, gender differences

Sex is one of biology's, that is, life's most potent experimental variables. So, are there sex differences in pain? And are these sex differences applicable clinically? The answer to both questions is decidedly yes, of course. But we still have a long way to go. We have much to learn from the study of females, making use of the lifelong changes in their reproductive conditions as experimental variables. We also have much to learn from animals, especially if we apply what we know about their social lives. However, the challenge in all of these studies is not first to look for some mythical neurological entity called pain experience and then to learn how sex modulates it, but rather to seek to understand the rules by which sex influences all of biology's mutually modulatory factors -- social, psychological, physiological, cellular, molecular, and genetic -- that collectively create the motivating circumstances we designate as pain. It appears almost beyond doubt that on the one hand these factors interact to make women more vulnerable to these circumstances than men, but on the other hand that women have more varied mechanisms for balance. Happily, the details of these sex differences at all levels biological (social to genetic) are now emerging in a rapidly growing body of literature that promises new insights into and applications for the individual person, male or female, in persistent pain.

Are there sex differences in pain? For experimentally delivered somatic stimuli, females have lower thresholds, greater ability to discriminate, higher pain ratings, and less tolerance of noxious stimuli than males. These differences, however, are small, exist only for certain forms of stimulation and are affected by many situational variables such as presence of disease, experimental setting, and even nutritive status. For endogenous pains, women report more multiple pains in more body regions than men. With no obvious underlying rationale, some painful diseases are more prevalent among females, others among males and, for many diseases, symptoms differ between females and males. Sex differences in attitudes exist that affect not only reporting, coping, and responses to treatment, but also measurement and treatment. So many variables are operative, however, that the most striking feature of sex differences in reported pain experience is the apparent overall lack of them. On the other hand, deduction from known biological sex differences suggests that these are powerful sex differences in the operation of pain mechanisms. First, the vaginal canal provides an additional route in women for internal trauma and invasion by pathological agents that puts them at greater risk for developing hyperalgesia in multiple body regions. Second, sex differences in temporal patterns are likely to give rise to sex differences in how pain is 'learned' and stimuli are interpreted, a situation that could lead to a greater variability and wider range of pains without obvious peripheral pathology among females. Third, sex differences in the actions of sex hormones suggest pain-relevant differences in the operation of many neuroactive agents, opiate and nonopiate systems, nerve growth factor, and the sympathetic system. Thus, while inductive analysis of existing data demonstrate more similarities than differences in pain experience between females and males, deductive analysis suggests important operational sex differences in its production.

Research was conducted to determine the interrelationship among insulin action, total or regional adiposity, and sex in black non-insulin-dependent diabetes mellitus (NIDDM) subjects. Insulin-mediated glucose disposal was measured by the euglycemic insulin clamp and adipose distribution using computed axial tomography (22 scans) in 32 black men and 20 black women with NIDDM. Visceral fat explained a significant portion (34%) of variance in insulin-mediated glucose disposal while total or subcutaneous fat and sex did not.

An in vivo enteral ethanol feeding model was utilized to determine the mechanisms responsible in the high susceptibility of females to alcohol-induced liver injury. Analysis of female susceptibility to alcohol-induced injury based on a novel ethanol feeding model indicated the presence of higher plasma endotoxin levels in females compared to males after exposure to ethanol. Higher endotoxin levels in female also induced a more extensive Kupffer cell activation in females compared to males.

The differential release of ventral septal vasopressin was analyzed in male and female urethan-anesthetized rats to determine the role of the ventral septal area (VSA) in antipyresis. Intracerebroventricular injections of the end-mediators of prostaglandin E2 (PGE2) in conscious and anesthetized male and female rats indicated the presence of gender-related differences in response to PGE2. The differential response to PGE2 was due to the sexually dimorphic vasopressinergic innervation of the VSA.

The effect of female sex steroid hormones on the progression of sucrose-induced insulin resistance was analyzed in female rats subjected to high-sucrose feeding. Female Wistar rats fed on a high-sucrose diet did not exhibit changes in the levels of basal glucose, glucose infusion rate and clamp rate of glucose appearance compared to female rats fed on high-starch diets. Furthermore, sucrose- and starch-fed animals did not exhibit differences in plasma glycogen and tissue triglycerides.

Background. Gender differences in functioning among older adults have been well documented. Differential reporting of functional problems by men and women may contribute to this observed difference. The purpose of this study was to examine the gender differences in functional ability by comparing self-reported function to observed performance of physical tasks. Methods. In 1988, 1,458 men and women ages 71 and older from the New Haven site of the Established Populations for the Epidemiologic Study of the Elderly (EPESE) self-reported activities of daily living (ADL) disability and functional limitations. Subjects' ability to perform 7 tasks was observed. Gender differentials in 'accurate' and 'inaccurate' reporting were determined by examining comparable self-reports and performance measures. Logistic regression determined how much of the gender differential in self-reported function was explained by performance ability. Results. More women than men reported disability and functional limitation, and women had poorer performance scores for every task. Compared to similar performance items, self-reports of function were accurate for the majority of men and women. However, among those who inaccurately reported function, more men than women underreported disability and more women than men overreported disability. Overall performance explains all of the gender difference in ADL disability and most of the difference in functional limitation. Conclusions. These results suggest that both men and women generally report their disability accurately, and women's higher prevalence of reported functional problems is probably a reflection of true disability for most disability measures.

Ninety-three Finnish females with a 45,X chromosome constitution, 78 first-degree female, and 37 first-degree male relatives were examined to determine the frequency and expression of torus mandibularis. The results indicate that among adults the frequency of the trait was significantly lower and the expression weaker in the 45,X females than in male control relatives. A similar trend was observed in comparison to normal females. In juveniles the trend was reversed. Our findings suggest that the sex chromosomes may have an influence on the occurrence, expression, and timing of development of the mandibular torus. Sexual dimorphism in the manifestation of torus mandibularis may result particularly from the effect of the Y chromosome on growth. KEY WORDS Chromosome aneuploidy, Sex chromosomes, Torus mandibularis, Human

The effects of aging and gender on diurnal heart rate variability was investigated as measurements of R-R intervals during a 24-hr. period using a Holter electrocardiogram. Male subjects showed higher values for the low-frequency (LF) component of cardiac beta-adrenergic function than female subjects. There were no differences in the peak of parasympathetic function between the two sexes. There was a significant relationship between LF and age, suggesting that heart beat is affected by aging and gender.

Elizabeth Blackwell presented a model of human sexuality that stressed the physiological similarities between males and females, a unique one-body model in the 19th century. Blackwell's use of the female body as a basic form can provide a framework for subsequent theories of sexuality. Blackwell's ideas about women controlling the activities of their bodies is similar to current feminist thinking, and was not meant to control men's sexuality.

Cardiovascular responses to stressful stimuli have been implicated in the development of cardiovascular disease. However, the effects of social stressors on short-term changes in blood pressure and heart rate (i.e., cardiovascular reactivity [CVR]) are not well understood. The independent effects of an incentive to exert interpersonal influence and the expression of socially controlling behavior on CVR were examined in 96 undergraduates. For men, both the incentive to exert influence and the enactment of a controlling interpersonal style produced larger increases in systolic blood pressure. By contrast, although the incentive to be influential increased women's CVR, the enactment of a cooperative role produced the largest increases in blood pressure among women. The effects of social dominance on CVR, sex differences in CVR, and interpersonal approaches to the study of these psychophysiological mechanisms are discussed.

The purpose of the study was twofold: (1) to examine any gender differences in the performance of a pre-employment selection test using the incremental lifting machine (ILM); and (2) to formulate recommendations regarding analyses of selection fairness in studies of pre-employment screening tests and devices. Data were collected in a series of studies designed to permit analyses of: (1) dynamic measures derived for a 1.8 m maximum ILM strength test; (2) relationships between ILM test scores and performance of a maximal box-lifting task using three different protocols; (3) the impact of anthropometric measures on performance of both test and task; (4) prediction of actual task performance; and (5) accuracy of the ILM screening test for three different cut-off standards. Results revealed that females differed significantly from males in their performance of a 1.8 m maximum ILM strength test in terms of timing, displacement, velocity, acceleration, force and power. Maximum ILM scores attained by females were poorly correlated with maximum box-lifting scores, but they were significantly related to body weight. Also, regression analyses based on ILM scores and associated dynamic parameters accounted for twice as much variance in box-lifting scores for males than for females. Furthermore, the use of cut-off standards of 22.7 kg and 27.3 kg produced a percentage of false negative results for females (12% and 32% respectively), but not for males. Also, for the cut-off level of 27.3 kg, female selection rates were only 56% of the selection rates for males. Issues for future investigation are recommended. Keywords: incremental lifting machine, selection procedures, pre-employment screening, gender differences

Psychological research has now clearly demonstrated that there is a significant difference between men and women in their performance on certain spatial tasks. Evidence further suggests that this difference has a neurological basis. This hypothesis is well enough established to have inspired several additional hypotheses concerning the evolutionary origin of the difference, including hypotheses emphasizing male hunting, female foraging, and male reproductive strategy. In this article we examine these hypotheses by placing them against the evidence for the neurological basis for the sex difference and the archaeological evidence for the evolution of spatial thinking in general. Given the probable source of the neurological difference in the timing of fetal testosterone, hypotheses that emphasize selection for female cognitive abilities are handicapped from the start. The hypotheses favoring male hunting and male reproductive strategy stumble when evaluated in light of the timing of the evolution of spatial cognition; archaeological evidence for the proposed selective behaviors and for the spatial abilities in question (e.g., mental rotation) do not correspond in a way that would permit a link between them. We conclude that none of the proposed adaptationist hypotheses fit the evidence as it currently exists, and that the modern sex difference in spatial cognition is almost certainly an evolutionary by-product of selection for optimal rates of fetal development. KEY WORDS Human evolution, Sex differences, Cognition, Stone tools

Recently, sex differences in the structures of the human hypothalamus and adjacent brain structures have been observed that seem to be related to gender, to gender problems such as transsexuality, and to sexual orientation, that is, heterosexuality and homosexuality. Although these observations have yet to be confirmed, and their exact functional implications are far from clear, they open up a whole new field of physiological structural-functional relationships in human brain research that has so far focused mainly on such relationships in pathology.

Experimental investigations of the blood flow (BF) pattern of female and male rabbits under normothermic and heat-stressed conditions reveal the presence of sex differences, indicating the sex-dependence of BF modulation in peripheral organs. Cardiac output during heat stress remains the same in both sexes. Females exhibit high BF to sternum, diaphragm, spleen and intercostal and skeletal muscles and low BF to the ear and toe skin and to nasal turbinates. The thermal state-by-sex interaction observed in many organs suggests that the heat stressed-males have a higher BF than the controls.

Experiments testing the existence of gender differences in the reflex responses to chemical and mechanical stimulation in rats reveal that the suppression of reflex responses of lumbar sympathetic nerve activity is more in females than in males for chemical and mechanical stimulation while no gender variations are seen for reflex suppression of mean arterial pressure and heart rate. The variations are attributable to the high left ventricular weight-to-body ratio in the females.

Women have been reported to be more positive about same-gender touch, but cross-cultural information about this touch is limited. Male and female students from Chile (n = 26), Spain (n = 61), Malaysia (n = 32), and the US (n = 77) completed a same-gender touch scale. As in past studies, US women had more positive scores than US men. Malaysians had more negative scores than the other three groups. Spanish and US students had more positive scores than Chilean students. National differences in attitudes toward particular types of touch were also noted. The need for new methods for examining cross-cultural differences in touch was discussed.

A large sample of hip bones of known sex coming from one modern population is studied morphologically and by multivariate analysis to investigate sexual dimorphism patterns. A principal component analysis of raw data shows that a large amount of the hip bone sexual dimorphism is accounted for by size differences, but that sex-linked shape variation is also very conspicuous and cannot be considered an allometric consequence of differences in body size between the sexes. The PCA of transformed ('shape') variables indicates that the female hip bones are different in those traits associated with a relatively larger pelvic inlet (longer pubic bones, a greater degree of curvature of the iliopectineal line, and a more posterior position of the auricular surface), as well as a broader sciatic notch. The analysis of nonmetric traits also shows marked sexual dimorphism in the position of the sacroiliac joint in the iliac bone, in the shape of the sciatic notch, in pubic morphology, and in the presence of the pre-auricular sulcus in females. When the australopithecine AL 288-1 and Sts 14 hip bones are included in the multivariate analysis, they appear as 'ultra-females.' In particular these early hominids exhibit extraordinarily long pubic bones and iliopectineal lines, which cannot be explained by allometry.

The role of prostaglandins in cortical and outer medullary autoregulatory responses were studied by comparing renal blood flow (RBF) in male and female rats. In male rats, autoregulatory activity was observed in both cortical and medullary circulation at 100 mmHg arterial pressure. Quinapril increased RBF while no significant effects were noted with indomethacin. Among the female rats, autoregulatory activity was observed only in the cortex. Data gathered suggest that prostaglandins interfere with autoregulation of medullary RBF in.

Total lengths of the 19 diaphyseal hand bones were measured from standardized radiographs of healthy American whites as young adults (ca. 21 years) and again at ca. 55 years of age. The four hand-bone rows exhibit distinctive length changes: Distal and middle phalanges continue to increase significantly in length, proximal phalanges constitute a transition zone of little change, and metacarpals uniformly decrease in length. Clear-cut sex differences are noteworthy: Males change more (lose more in some bone rows, gain more in others) than females. Progressive elongation was greatest in the distal phalanges where apposition around the distal aspect ('tufting') is not constrained by a joint or epiphysis. Loss of bone length in the metacarpals by subchondral resorption is consistent with documented reductions in activity levels and grip strength with age, as well as diminished joint spaces which alter loading of the joints.