Examination stress affects plasma levels of TSH and thyroid hormones differently in females and males

Plasma levels of TSH and thyroid hormones in 22 male and 27 female medical students were determined by radioimmunoassay before and after an academic examination. The plasma values of TSH were slightly higher in both sexes on the examination day than on the control days. The values were lower after the examination than before it in females but not in males. Plasma levels of T3 were higher in males than in females on the examination day. In contrast, the plasma rT3 values were higher for females on the examination day than on control days. The plasma levels of T4 were similar in both sexes. The results suggest that during psychic stress, the pituitary-thyroid endocrine system of the female reacts differently from that of the male.     

Musically induced arousal affects pain perception in females but not in males: a psychophysiological examination

The present study investigated affective and physiological responses to changes of tempo and mode in classical music and their effects on heat pain perception. Thirty-eight healthy non-musicians (17 female) listened to sequences of 24 music stimuli which were variations of 4 pieces of classical music. Tempo (46, 60, and 95 beats/min) and mode (major and minor) were manipulated digitally, all other musical elements were held constant. Participants rated valence, arousal, happiness and sadness of the musical stimuli as well as the intensity and the unpleasantness of heat pain stimuli which were applied during music listening. Heart rate, respiratory rate and end-tidal PCO(2) were recorded. Pain ratings were highest for the fastest tempo. Also, participants' arousal ratings, their respiratory rate and heart rate were accelerated by the fastest tempo. The modulation of pain perception by the tempo of music seems to be mediated by the listener's arousal.     

Estradiol and phytoestrogens differently influence the rodent postmenopausal mammary gland

OBJECTIVE: In the following study, we investigated treatment-related changes in mammary gland histomorphology and structure after the administration of soy to adult virgin ovariectomized (OVX) female rats. Additionally, mammary receptor regulation was extensively evaluated by immunohistochemical analysis, and tissue proliferative activity analyzed by cell nuclear proliferating antigen expression (Ki67). DESIGN: OVX rats were treated, for 6 weeks, with either the vehicle, the soy extract (SSE 100 mg/kg/d PO), or 17beta-estradiol (0.5 mg/kg/d PO); a sham control group (SHAM) was also included in the study. When killed, mammary glands were collected and subsequently processed for light microscopy or immunohistochemistry. Immunoreactivity was quantified by a scoring system that took into account both the percentage of positive cells and the intensity of the staining. RESULTS: The 17beta-estradiol--treated rats had stimulated mammary glands compared with OVX rats, with an average lobulo-alveolar development not different from the SHAM controls. Only a partial regression of the glandular atrophy was observed in OVX rats receiving 100 mg/kg/d SSE, with a histological appearance between that of the OVX and SHAM controls. No significant changes were observed among experimental groups in the median ERalpha scores of the epithelial compartment (score of 3 in all groups); in the stromal compartment, a tendency toward decreased expression was seen with 17beta-estradiol rats compared with OVX controls (scores of 2 and 5, respectively). A significant reduction in ERbeta immunostaining was observed in the mammary glands of SSE-treated rats, in both epithelium and stroma (scores of 4 and 3, respectively), compared with those of OVX controls (score of 8 in both compartments). The ERbeta receptor status was not significantly affected by 17beta-estradiol. Compared with OVX rats (score of 1), PR expression was up-regulated by 17beta-estradiol (score of 6), whereas an ovariectomy-like pattern was observed after the administration of SSE (score of 0). Ki67 immunoreactivity in the epithelium and stroma was increased by the administration of 17beta-estradiol (scores of 4 and 5, respectively) and was unchanged after SSE treatment (scores of 0 and 2, respectively), compared with OVX controls (scores of 1 and 2, respectively). CONCLUSIONS: The differences observed in the histological pattern, hormonal receptor status regulation, and Ki67 modulation suggest a different role for phytoestrogens and 17beta-estradiol in postmenopausal rodent mammary glands.     

The facioscapulohumeral muscular dystrophy (FSHD1) gene affects males more severely and more frequently than females

We investigated 52 families of patients with facioscapulohumeral muscular dystrophy (FSHD1), including 172 patients (104 males and 68 females). Among 273 DNA samples which were analyzed with probe p13E-11, 131 (67 males and 64 females) were shown to carry an EcoRI fragment smaller than 35 kb; 114 among them were examined clinically and neurologically. Results of the present investigation showed that: a) there is no molecular evidence for autosomal or X-linked recessive inheritance of FSHD1; b) an excess of affected males, which is explained by a significantly greater proportion of females than males among asymptomatic cases and a significantly greater proportion of affected sons than daughters observed in the offspring of asymptomatic mothers; c) the penetrance of the FSHD1 gene until age 30 was estimated as 83% for both sexes but was significantly greater for males (95%) than for females (69%); d) new mutations occur significantly more frequently in females than males among somatic/germinal mosaic cases; and e) severely affected cases originated more often through new mutations or were transmitted through maternal than through paternal lines including somatic/germinal mothers. These observations have important implications for understanding the molecular mechanisms responsible for FSHD1 and for genetic and prognostic counseling according to the gender of the affected patient. Am. J. Med. Genet. 77:155–161, 1998. © 1998 Wiley-Liss, Inc.     

Force recovery after eccentric exercise in males and females

In this study we investigated force loss and recovery after eccentric exercise, and further characterized profound losses in muscle function (n=192 subjects – 98 males, 94 females; population A). Maximal voluntary contractile force (MVC) was assessed before, immediately after, and at 36 and 132 h after eccentric exercise. Two groups were then established (A₁ and A₂). Group A₁ demonstrated a >70% reduction in MVC immediately after exercise, but were recovering at 132 h after exercise. These subjects performed a follow-up MVC 26 days later (n=32). Group A₂ demonstrated a >70% reduction in MVC immediately post-exercise, but still exhibited a >65% reduction in force at 132 h post-exercise; these subjects also performed a follow-up MVC every 7 days until full recovery was established (n=9). In population A, there was a 57% reduction in MVC immediately post-exercise and a 67% recovery by 132 h post-exercise (P < 0.01), with no significant gender differences (P > 0.05). In group A₁, although more females (two-thirds) showed large force losses after exercise, these females demonstrated greater %MVC recovery at 132 h post-exercise (59% vs 44%) and at 26 days post-exercise (93% vs 81%) compared to the males. In group A₂, MVC recovery occurred between 33 and 47 days post-exercise. In conclusion, 21% of all subjects showed a delayed recovery in MVC after high-force eccentric exercise. Although there were no significant gender differences in force loss, a disproportionately larger number of females demonstrated force reductions of >70%. However, their recovery of force was more rapid than that observed for the males who also demonstrated a >70% force loss. Accepted: 2 October 2000     

Testosterone affects formalin-induced responses differently in male and female rats

To evaluate the role of testosterone in pain modulation, we subcutaneously injected male and female rats with testosterone propionate (TP, 5 mg/kg in oil) or oil for 6 days; on the seventh day, all rats were subjected to the formalin test (10%, 50 microl). Behaviours were recorded in an open field (60 min). At the end of the formalin test, the rats were anaesthetized to collect blood from the abdominal aorta. Among the formalin-induced responses, licking was higher in females than males and was decreased by TP in females; jerking and flexing were only slightly affected by treatment. TP increased testosterone plasma levels in both sexes. These results indicate a role of testosterone in modulating formalin-induced responses. The effects appear to be different in males and females.     

Acetazolamide affects breathing differently in ICR and C57 mice

Acetazolamide (ACZ) administration was compared on ventilation in outbred male ICR Swiss Webster (ICR) and inbred C57BL/6J (C57) mice, used in development of transgenic strains. We hypothesized that in both strains ACZ would affect breathing similarly. Mice received intraperitoneally vehicle and the next week ACZ (40 mg/kg), and were exposed to air for 90 min, followed by 5-min exposure to 10% O(2), air for 15 min, and to 5 min of 5% CO(2) in O(2). Ventilation was evaluated using plethysmography. ACZ stimulated ventilation in both stains exposed to air. C57 mice minimally increased frequency and tidal volume, whereas ICR mice markedly increased frequency. Strain differences in the ventilatory pattern in response to hypoxia and hypercapnia occurred. ACZ-treated ICR mice decreased hypoxic responsiveness to 50% of vehicle values, whereas ACZ had no effect in C57 mice. ACZ decreased hypercapnic ventilatory responsiveness in both strains. Differential effects of ACZ breathing in these two strains suggest that genetic factors modulate its effect on breathing.     

Perception of multiple-breath inspiratory resistive loads in males and females

Resistive load magnitude estimation (ME) was measured over multiple breaths in male and female subjects. It was hypothesized that multiple breaths against a range of resistive loads would result in a change in the perceived load magnitude as a function of load magnitude and the number of inspiratory efforts. It was further hypothesized that males and females would differ in their perceptual response to sustained breathing against inspiratory resistive loads. The subjects were tested in a sound isolated room and respired through a non-rebreathing valve, the inspiratory port connected to the loading manifold. The subject inspired to a peak airflow target for each breath. Each R load was presented for 10 continuous breaths. The load was estimated at breath 1, 5, and 10 using a modified Borg scale. Each 10-breath load presentation was presented in a randomized block. There was no significant group difference between the ME for breath 1 and 10 for small R loads, but a significant group difference for large R loads. The ME for males did not change between breath 1 and 10 for the small load magnitudes, but decreased with large loads. The ME for the 10th breath of the large R load was greater than the 1st breath for females. Males estimated the large R load on the 1st breath the same as females but the ME on the 10th breath was significantly less for males compared to females. These results demonstrate that magnitude estimation of large resistive loads with a sustained 10-breath trial elicits significant increases in females, but significantly decreased in males. The increase in ME may represent increased respiratory discomfort for females and the decrease habituation in males.     

Maternal effect on intelligence in fragile X males and females

If the mother is the fragile X gene carrier, her daughters (and sons) with the mutation are at high risk of mental retardation. If the father is the (clinically unaffected) carrier, his daughters are normal. This is strong evidence for a maternal effect. The decreased penetrance and variable expressivity in fra(X) offspring of carriers could be related, at least in part, to variabile expression or availability of some maternal factor between pregnancies. We hypothesize a maternal effect in fra(X), with variability in intelligence of heterozygotes and hemizygotes mediated mainly by the maternal uterus or placenta by virtue of different patterns of lyonization in those tissues between pregnancies. If the mother is a carrier, the maternal placenta could develop with a skewed proportion of the normal or the fra(X) genetically active. Each female or male embryo could be exposed to very different environments with respect to genetic activity of the fra(X) chromosome, depending on the site of implantation within the uterus. If the father contributes the fra(X), the intrauterine environment is invariably normal and so are the daughters. Modifiers of the intrauterine effect could include lyonization patterns in tissues of the carrier fetus, and preferential inactivation of the paternal X in extra-embryonic tissues. The ultimate phenotype of the developing heterozygote and hemizygote may be determined by a threshold effect and interaction between the maternal genotype, the placental genotype, and the fetal genotype. The possibility of maternal effect is testable and has implications for treatment.     

Epidemiology of gonadal germ cell cancer in males and females

The epidemiology of testicular germ cell cancer is relatively well understood, but less is known about the epidemiology of ovarian germ cell cancer. Cases of testicular (7910) and ovarian (453) germ cell cancer diagnosed 1960-1999 were extracted from the Thames Cancer Registry. The incidence rate in males doubled in the period from 2.0 to 4.4 per 100,000. In females the rate was much lower but the rate of increase over the period was similar to the increase in males. In both sexes the incidence increased sharply around the age of onset of puberty and decreased in older age groups. The biological mechanism of initiation of germ cell carcinogenesis is similar in males and females and probably occurs with roughly the same frequency in the two sexes. In males, the initiated cell population is promoted by the normal action of adult sex hormones to form carcinoma in situ, consisting of many millions of cells. The incidence of testicular cancer is rate limited by the development of carcinoma in situ. The key difference between males and females, which may explain the different levels of incidence, is the much lower number of susceptible cells in females at the time of puberty.     

Aging process of leg muscle endurance in males and females

Summary In order to estimate muscle endurance during knee extension (KME) and plantar flexion (PME) using a simple method, holding times for the half-squatting posture for KME and for the calf-raising posture for PME were measured in 3,792 males and 3,620 females aged between 6 and 79 years. The regression lines of the aging process for KME and PME in both sexes were determined. Peak values were found at 13 years in males and 12 years in females for KME, and at 15 years in males and 16 years in females for PME. The mean values increased sharply with age up to each peak and then decreased abruptly to a low level at around 20 years, thereafter declining gradually. The values of KME as a percentage of the peak value were 71, 75 and 34 at the ages of 6, 20 and 70–79 years respectively in males, while the corresponding values were 80, 77 and 36 for females. The values of PME at these ages were 34, 93 and 69 in males and 54, 91 and 73 in females. The mean values for males were generally higher than those for females. These results suggest that endurance of the leg muscles differs according to age, sex and the region of the leg muscle. These data will be useful as standard values for evaluating endurance and for prescribing suitable exercise for the promotion of physical fitness.     

Prevalence of fragile X syndrome in males and females in Indonesia

AIM: To investigate the prevalence of fragile X syndrome (FXS) in intellectually disabled male and female Indonesians. METHODS: This research is an extension of a previously reported study on the identification of chromosomal aberrations in a large cohort of 527 Indonesians with intellectual disability (ID). In this previous study, 87 patients had a chromosomal abnormality, five of whom expressed fragile sites on Xq27.3. Since FXS cannot always be identified by cytogenetic analysis, molecular testing of the fragile X mental retardation 1 CGG repeat was performed in 440 samples. The testing was also conducted in the five previously identified samples to confirm the abnormality. In total, a molecular study was conducted in 445 samples (162 females and 283 males). RESULTS: In the cohort of Indonesian ID population, the prevalence of FXS is 9/527 (1.7%). The prevalence in males and females is 1.5% (5/329) and 2% (4/198), respectively. Segregation analysis in the families and X-inactivation studies were performed. We performed the first comprehensive genetic survey of a representative sample of male and female ID individuals from institutions and special schools in Indonesia. Our findings show that a comprehensive study of FXS can be performed in a developing country like Indonesia where diagnostic facilities are limited. CONCLUSION: The prevalence of FXS is equal in females and males in our study, which suggests that the prevalence of FXS in females could be underestimated.     

Responses to eccentric and concentric resistance training in females and males

The adaptive responses to 12 weeks of accommodated resistance training were compared in females (n= 11) and males (n= 11). They performed four to five sets of six maximum bilateral coupled concentric and eccentric quadriceps muscle actions at 1.05 rad s^-1 three times per week. Uni- and bilateral concentric and eccentric peak torque at different angular velocities (0.52, 1.57 and 2.62 rad s^-1), three repetition maximum half-squat and vertical jump height were measured before and after training. Both groups displayed marked increases (P < 0.05) in concentric and eccentric peak torque at all angular velocities. The relative increases (P < 0.05) in unilateral concentric (26 vs. 26%) and eccentric (28 vs. 36%) peak torque across speeds were similar in females and males. The corresponding increases (P < 0.05) in bilateral concentric and eccentric peak torque across speeds were 20 vs. 28% and 24 vs. 39% respectively. The three repetition maximum half-squat (20 vs. 25%) and vertical jump height (10 vs. 8%) increased (P < 0.05) equally in females and males. These results suggest that the overall increases in concentric and eccentric peak torque and functional strength, in response to short-term accommodated resistance training, occur at a rate that is independent of sex. The torque-velocity relationship, however, appears to change in males suggesting a relatively greater enhancement of maximum voluntary force in the slow-speed, high-force region.     

Age-related changes in root transparency of teeth in males and females

The correlation between root transparency and chronological age was examined in a sample of 366 intact teeth from 295 individuals of known sex and age. Correlations, especially for anterior teeth (incisors and canines), were slightly higher in females than males, but neither the slopes nor the Y intercepts of the regression lines were significantly different. Linear regression analysis to predict age separately for males, females, and the total sample resulted in standard errors of estimate ranging from 8.88 to 11.46 years.     

Salivary testosterone and creative musical behavior in adolescent males and females

In a longitudinal study, salivary testosterone levels were assessed in 3 subsequent years in adolescent boys and girls who had documented creative musical talent in their early teens. Decrease of creative musical behavior in adolescent boys was attributed, inter alia, to a testosterone increase exceeding a hypothesized optimal testosterone range for the expression of creative musical behavior. Left‐handers, especially left‐handed boys, were superior to righthanders on a test measuring musical talent. Testosterone levels did not differ between the handedness groups. Sex differences in salivary testosterone were not observed by a mean age of 13.5. Age was more important than mutation in boys and menarche in girls with respect to testosterone rises during puberty. Circadian rhythm in salivary testosterone levels was found in both sexes.     

Inspiratory and expiratory lung pressure-volume curve in healthy males and females

Quasistatic lung inspiratory and expiratory pressure-volume curves were obtained in 58 healthy nonsmoking males (mean age +/- SD: 42.8 +/- 15.1 years; range 22.70) and 56 healthy nonsmoking females (mean age +/- SD: 41.4 +/- 15.6 years; range: 21-76). Inspiratory and expiratory lung recoil pressures were measured at fixed percentages of TLC (100, 95, 90, 80, 70, 60 and 50%). In both sexes, inspiratory as well as expiratory lung recoil pressures were found to decrease linearly with aging (p less than 0.01 for all r values). There was no significant difference between males and females. At and above the 70% TLC level, the slopes of the age-related decreases in lung recoil were similar for the inspiratory and expiratory curves. At the 60% TLC level, the decrease in expiratory lung recoil was significantly (p less than 0.01) faster than the decrease in inspiratory lung recoil, presumably reflecting the influence of airway opening on the inspiratory pressure in older subjects. The shape of the expiratory PV curve described by the K index of the exponential model was similar in both sexes and changed with aging, K increasing significantly (p less than 0.01). By contrast, the shape of the inspiratory limb of the PV curve did not vary with aging. Consequently, the shape of the inspiratory PV curve cannot be predicted from the expiratory one and has to be measured directly.     

Stroke: understanding the differences between males and females

Stroke is a significant cause of death and long-term disability in the USA. The incidence, mortality, and outcomes of stroke are significantly different between men and women. As with many diseases that affect men and women differently, an understanding on the reasons underlying those differences is critical to effective diagnosis and treatment. This review will examine the sex differences in stroke in both humans and animal models of stroke and review what is known about potential mechanisms underlying these differences. It is clear that there is a complex interaction between hormonal, genetic, and unknown factors at play in generating the sex differences in stroke.