Head and neck anthropometry, vertebral geometry and neck strength in height-matched men and women

Women have an increased incidence of whiplash injury and neck pain compared to men. Physical and numerical models represent one avenue to explore and potentially explain these gender differences, but a valid model of the female neck does not yet exist. A fundamental question in the development of a female neck model is whether female necks are simply scaled versions of male necks, or whether there are significant inter-gender geometrical differences. The goal of this study was to quantify differences in head and neck geometry and neck strength in pairs of male and female subjects matched for standing height and neck length. Based on 14 matched pairs of men and women, we found that most head and neck anthropometric parameters were significantly smaller in females compared to males. Moreover, gender differences in a number of neck anthropometry parameters (an average of 9-16% smaller in females) were larger than differences in head anthropometry parameters (an average of 3-6% smaller in females). Female vertebrae between C3 and C7 were significantly smaller than male vertebrae in the anterior-posterior dimension (p < 0.012) but not in the medial-lateral dimension (p > 0.07). Female necks were also significantly weaker than male necks (32% weaker in flexion and 20% weaker in extension; p < 0.001), and these strength differences corresponded well to those predicted solely from the observed geometric differences. These results demonstrate that male and female necks are not geometrically similar and indicate that a female-specific model will be necessary to study gender differences in neck-related disorders.     

Face Gender Influences the Looking Preference for Smiling Expressions in 3.5-Month-Old Human Infants

Young infants are typically thought to prefer looking at smiling expressions. Although some accounts suggest that the preference is automatic and universal, we hypothesized that it is not rigid and may be influenced by other face dimensions, most notably the face’s gender. Infants are sensitive to the gender of faces; for example, 3-month-olds raised by female caregivers typically prefer female over male faces. We presented neutral versus smiling pairs of faces from the same female or male individuals to 3.5-month-old infants (n = 25), controlling for low-level cues. Infants looked longer to the smiling face when faces were female but longer to the neutral face when faces were male, i.e., there was an effect of face gender on the looking preference for smiling. The results indicate that a preference for smiling in 3.5-month-olds is limited to female faces, possibly reflective of differential experience with male and female faces.     

Growth and survivorship as proximate causes of sexual size dimorphism in peninsula dragon lizards Ctenophorus fionni

Males and females differ in body size in many animals, but the direction and extent of this sexual size dimorphism (SSD) varies widely. Males are larger than females in most lizards of the iguanian clade, which includes dragon lizards (Agamidae). I tested whether the male larger pattern of SSD in the peninsula dragon lizard, Ctenophorus fionni, is a result of sexual selection for large male size or relatively higher mortality among females. Data on growth and survivorship were collected from wild lizards during 1991–1994. The likelihood of differential predation between males and females was assessed by exposing pairs of male and female lizards to a predator in captivity, and by comparing the frequency of tail damage in wild‐caught males and females. Male and female C. fionni grew at the same rate, but males grew for longer than females and reached a larger asymptotic size (87 mm vs. 78 mm). Large males were under‐represented in the population because they suffered higher mortality than females. Predation may account for some of this male‐biased mortality. The male‐biased SSD in C. fionni resulted from differences in growth pattern between the sexes. The male‐biased SSD was not the result of proximate factors reducing female body size. Indeed SSD in this species remained male‐biased despite high mortality among large males. SSD in C. fionni is consistent with the ultimate explanation of sexual selection for large body size in males.     

Sexual behaviour and reproductive competition in male wild and domestic Norway rats

The copulatory behaviour of male wild Norway rats (Rattus norvegicus) exposed individually to females in hormone-induced oestrus is characterized by fewer mounts and intromissions per ejaculatory series, shorter ejaculation latencies, and longer ejaculatory clasps than the copulatory behaviour of domestic males. Competition between wild and domestic males tested simultaneously in pairs produced only minor changes in copulatory behaviour. The reproductive success of wild and domestic male pairs simultaneously exposed to naturally cycling females was nearly equal in both the laboratory and an outdoor enclosure. Genotype of the female had little effect on male copulatory behaviour. The copulatory behaviour of sexually naive and experienced domestic rats did not differ. However, most sexually naive wild males failed to exhibit copulatory behaviour under the test conditions employed.     

Racial/Ethnic and Gender Differences in Concern with Weight and in Bulimic Behaviors Among Adolescents

FIELD, ALISON E, GRAHAM A COLDITZ, KAREN E PETERSON. Racial/ethnic and gender differences in concern with weight and in bulimic behaviors among adolescents. This study examined cross-sectional gender and racial/ethnic differences in bulimic behaviors among adolescents. Subjects were 704 male and 621 female students at a large urban public high school in the Northeast. Approximately 61% of the girls and 43% of the boys reported trying to lose weight or maintain their current weight; 2.0% of the students reported using laxatives or vomiting to control their weight. The use of these behaviors to control weight was only slightly more common among girls than boys (2.7% vs. 1.4%,p=0.1). Although more black than white girls used laxatives or vomiting to control weight (odds ratio [OR]=11.9, 95% confidence interval [CI] 1.5–95.3), there were no racial/ethnic differences in these behaviors among boys. However, Hispanic boys were twice as likely as white boys to binge eat at least monthly (OR=2.0, 95% CI 1.1–3.6). Our results suggest that bulimic behaviors affect male and female adolescents from a variety of racial/ethnic backgrounds. In addition, in contrast to the large gender differences in the prevalence of dieting and binge eating, more modest differences were documented in the prevalence of using vomiting and laxatives to control weight.     

Chloroplast DNA variation and parentage analysis in 55 apples

The chloroplastic atpB-rbcL spacer and the first 53 codons of the rbcL coding sequence was sequenced for 40 apple cultivars and 15 wild species. This chloroplast DNA region is 904 base pairs long, and only five mutations sites were found among the tested samples. Although the cpDNA variation was low, some parentages are proposed based on the maternal inheritance of plastid DNA: the male and female parents are specified, or else suggested, for Worcester, Discovery, Starking, Starkrimson, Kidd's Orange Red, Priscilla, and Gloster, as well as for the putative wild origin for Malus x domestica.     

Male and Female Mating Behavior is Dependent on Social Context in the Butterfly Bicyclus anynana

Reproduction is often more costly to females than it is to males, leading to the evolution of ornamented or competitive males and choosy females. Reproduction costs to females, however, can be reduced through nuptial gifts provided by males. These gifts, by increasing female survival or fecundity, can promote the evolution of mutual mate choice, ornamentation, or competition in both sexes, as well as plasticity in mating behavior dependent on social context. We tested for plasticity in male and female mating behavior in a species of butterfly, Bicyclus anynana, where male spermatophore gifts contribute to female survival and fecundity, and where mutual mate choice and ornamentation were previously established. We examined the effect of a sexual competitor on male–female interactions by observing and comparing the behavior of male–female pairs with that of triads containing either an extra male or an extra female. In the presence of a sexual competitor both males and females copulated less than when in male–female pairs, regardless of the direction of sex-ratio skew. Active males increased their own likelihood to copulate, while active females increased their likelihood of being courted. In addition, there was an effect of social context on relative rates of male and female courting and flying. These results suggest that both males and females change their mating behavior in response to social context in the butterfly Bicyclus anynana.     

The Effect of Social Environment on Male–Male Competition in Guppies (Poecilia reticulata)

We examined male–male competition in guppies (Poecilia reticulata) to test for evidence of hierarchy formation and any subsequent effects on male mating success by comparing the interactions of pairs of males that were siblings and life‐long tank mates with those of unrelated pairs that had never met. These pairs of males were first observed in the absence of a female; then a female was added to gauge the effects of the initial male–male interactions on male sexual behaviour. The unfamiliar/unrelated pairs engaged in significantly more aggressive interactions such as physical contacts, nipping and chasing than the familiar/related pairs. Based on several previous studies, we suggest that familiarity played a greater role than relatedness in the differences in behaviour that we observed. Our results suggest that, in some circumstances, more aggressive males may have more mating opportunities than less aggressive males. Our results also indicate that males adjust their aggressive and courtship behaviours to the perceived intensity of competition for mates, based on the number of mature males in their rearing tanks. We suggest that male–male competition for mating opportunities may play a more important role in the guppy mating system than previously thought.     

Gender Differences in Patients with Takotsubo Cardiomyopathy: Multi-Center Registry from Tokyo CCU Network

Background

The clinical features of gender differences in takotsubo cardiomyopathy (TC) remain to be determined. The aim of this study was to evaluate the differences in clinical characteristics of male and female patients with TC.

Methods

We obtained the clinical information of 368 patients diagnosed with TC (84 male, 284 female) from the Tokyo CCU Network database collected from 1 January 2010 to 31 December 2012; the Network is comprised of 71 cardiovascular centers in the Tokyo (Japan) metropolitan area. We attempted to characterize clinical differences during hospitalization, comparing male and female patients with TC.

Results

There were no significant differences in apical ballooning type, median echocardiography ejection fraction, serious ventricular arrhythmias (such as ventricular tachycardia or fibrillation), or cardiovascular death between male and female patients. Male patients were younger than female patients (median age at hospitalization for male patients was 72 years vs. 76 years for female patients; p = 0.040). Prior physical stress was more common in male than female patients (50.0% vs.31.3%; p = 0.002), while emotional stress was more common in female patients (19.0% vs. 31.0%; p = 0.039). Severe pump failure (defined as Killip Class > III) (20.2% vs. 10.6%; p = 0.020) and cardiopulmonary supportive therapies (28.6% vs. 12.7%, p < 0.001) were more common in male than female patients. Multivariate analysis revealed that male gender (odds ratio = 4.32, 95% CI = 1.41–13.6, p = 0.011) was an independent predictor of adverse composite cardiac events, including cardiovascular death, severe pump failure, and serious ventricular arrhythmia.

Conclusions

Cardiac complications in our dataset appeared to be more common in male than female patients with TC during their hospitalization. Further investigation is required to clarify the underlying mechanisms responsible for the observed gender differences.     

Sequence of Centromere Separation: Role of Centromeric Heterochromatin

The late metaphase-early anaphase cells from various tissues of male Mus musculus, M. poschiavinus, M. spretus, M. castaneus, female and male Bos taurus (cattle) and female Myopus schisticolor (wood lemming) were analyzed for centromeres that showed separation into two daughter centromeres and those that did not show such separation. In all strains and species of mouse the Y chromosome is the first one to separate, as is the X or Y in the cattle. These sex chromosomes are devoid of constitutive heterochromatin, whereas all autosomes in these species carry detectable quantities. In cattle, the late replicating X chromosome appears to separate later than the active X. In the wood lemming the three pairs of autosomes with the least amount of centromeric constitutive heterochromatin separate first. These are followed by the separation of seven pairs of autosomes carrying medium amounts of constitutive heterochromatin. Five pairs of autosomes with the largest amounts of constitutive heterochromatin are the last in the sequence of separation. The sex chromosomes with medium amounts of constitutive heterochromatin around the centromere, and a very large amount of distal heterochromatin, separate among the very late ones but are not the last. These observations assign a specific role to centromeric constitutive heterochromatin and also indicate that nonproximal heterochromatin does not exert control over the sequence in which the centromeres in the genome separate. It appears that qualitative differences among various types of constitutive heterochromatin are as important as quantitative differences in controlling the separation of centromeres.     

An improved embryo-rescue protocol for hybrid progeny from seedless Vitis vinifera grapes × wild Chinese Vitis species

A highly efficient technique of embryo rescue is critical when using stenospermocarpic Vitis vinifera cultivars (female parents) to breed novel, disease-resistant, seedless grape cultivars by hybridizing with wild Chinese Vitis species (male parents) having many disease-resistance alleles. The effects of various factors on the improvement of embryo formation, germination, and plantlet development for seven hybrid combinations were studied. The results indicated that Beichun and Shuangyou were the best male parents. The best sampling time for ovule inoculation differed among the female parents. When hybrid ovules were cultured on a double-phase medium with five different solid medium types, percent embryo formation was highest (11.3–28.3%) on a modified MM3 medium. Percentages of embryo germination (15.4–55.4%) and plantlet development (11.15–44.6%) were all highest when embryos were cultured on Woody Plant Medium?+?5.7 μM indole-3-acetic acid?+?4.4 μM 6-benzylaminopurine?+?1.4 μM gibberellic acid?+?2% sucrose?+?0.05% casein hydrolysate?+?0.3% activated charcoal?+?0.7% agar. In the absence of other amino acids, the addition of proline significantly increased embryo formation (36.1%), embryo germination (64.6%), and plantlet development (90.5%). A highly efficient protocol has been developed for hybrid embryo rescue from seedless V. vinifera grapes?×?wild Chinese Vitis species that results in a significant improvement in breeding efficiency for new disease-resistant seedless grapes.     

Chemical communication of reproductive status in female cotton-top tamarins (Saguinus oedipusoedipus)

Among Callitrichids, scent secretions have been identified as carrying information regarding species, subspecies, gender, social status, individuality, hormonal status, and timing of ovulation. We propose that information regarding familiarity and reproductive status is also communicated. Seven male–female pairs of cotton-top tamarins (Saguinus oedipus oedipus) were presented with several drops of distilled water, a scent secretion from the female of that pair, scent secretions from unfamiliar, reproductively mature but noncycling females, and scent secretions from unfamiliar, reproductively cycling females. Behavioral responses from both males and females were recorded over a 10 min period. Differences in behavioral response for both males and females were significant across all four conditions. This indicates that cotton-top tamarins are capable of discriminating a familiar scent from an unfamiliar scent as well as the reproductive status of an unfamiliar female. The communication of this information may play an important role in regulating mate selection, reducing reproductive competition, and stabilizing transfers in and out of groups in the wild. Am. J. Primatol. 45:337–349, 1998. © 1998 Wiley-Liss, Inc.     

Analysis of Sex Differences in Preadmission Management of ST-Segment Elevation (STEMI) Myocardial Infarction

BackgroundMany reports suggest gender disparity in cardiac care as a contributor to the increased mortality among women with heart disease.ObjectiveWe sought to identify gender differences in the management of Myocardial Infarction (MI) Alert–activated ST-segment elevation myocardial infarction (STEMI) patients that may have resulted from prehospital initiation.MethodsA retrospective database was created for MI Alert STEMI patients who presented to the emergency department (ED) of an academic community hospital with 74,000 annual visits from April 2000 through December 2008. Included were patients meeting criteria for an MI Alert (an institutional clinical practice guideline designed to expedite cardiac catheterization for STEMI patients). Data points (before and after initiation of a prehospital alert protocol) were compared and used as markers of therapy: time to ECG, receiving β-blockers, and time to the catheterization laboratory (cath lab). Differences in categorical variables by patient sex were assessed using the χ² test. Medians were estimated as the measure of central tendency. Quantile regression models were used to assess differences in median times between subgroups.ResultsA total of 1231 MI Alert charts were identified and analyzed. The majority of the study population were male (70%), arrived at the ED via ambulance (60.1%), and were taking a β-blocker (67.8%) or aspirin (91.6%) at the time of the ED admission. Female patients were more likely than male patients to arrive at the ED via ambulance (65.9% vs 57.6%, respectively; P = 0.014). The median age of female patients was 68 years, whereas male patients were significantly younger (median age, 59 years; P < 0.001). The proportion of patients currently taking a β-blocker or low-dose aspirin did not vary by gender. Overall, 78.2% of the MI Alert patients arriving at the ED were MI2 (alert initiated by ED physician), and this did not vary by gender (P = 0.33). A total of 1064 MI Alert patients went to the cath lab: 766 male patients (88.9%) and 298 female patients (80.8%). Overall, the median time to cath lab arrival was 79 minutes for men and 81 minutes for women (P = 0.38). Overall, the median time to cath lab arrival significantly decreased from MI1 to MI3, (P_trend < 0.001). For prehospital-initiated alerts (MI3), the median time to cath lab arrival was the same for men and women (64 minutes; P = 1.0). For hospital-initiated alerts, time to cath lab arrival was 82 minutes for male patients and 84 minutes for female patients (P = 0.38). Prehospital activation of the process decreased the time to the cath lab by 19 minutes (P < 0.001; 95% CI, 13.2–24.8).ConclusionNo significant gender differences were apparent in the STEMI patients analyzed, whether the MI Alert was initiated in the ED or prehospital initiated. Initiating prehospital-based alerts significantly decreased the time to the cath lab.     

Does fetal sex affect pregnancy outcome?

Background: In maternal fetal medicine, gender differences in outcome are often observed.Objective: This article reviews the fetal sex-dependent differences found in many aspects of pregnancy, from conception through birth.Methods: The MEDLINE, EMBASE, and Current Contents databases were searched, for the years 1985 to 2006, using the following Medical Subject Headings and text words: fetal gender, finale, female, sex ratio at birth, pregnancy outcome, preterm birth, and stillbirth. The search was not limited by language. In addition, the bibliographies of known relevant articles were examined to capture any reports not already identified in the electronic search. All reports that provided information on gender differences in pregnancy outcome were included for review.Results: An extremely high male-to-female ratio was found in fetuses born after very short-duration pregnancy; this level declined around the 20th week and stabilized at term. In the absence of manipulation, both the sex ratio at birth and the population sex ratio have been found to remain consistent. A higher incidence of preterm birth and premature preterm rupture of membranes has been observed in different populations among mothers of male newborns compared with mothers of females. It has been speculated that this higher incidence may be linked to the relatively greater weight at lower gestational age of male newborns versus females. Women carrying male fetuses had higher rates of gestational diabetes mellitus, fetal macrosomia, failure to progress during the first and second stages of labor, cord prolapse, nuchal cord, and true umbilical cord knots. Cesarean sections were also more frequently found among male neonates compared with females.Conclusions: Male sex is an independent risk factor for adverse pregnancy outcome. Evidence suggests that females have an advantage over males, with a better outcome in the perinatal period, particularly after preterm birth.Key words: fetal gender, male, female, sex ratio of birth, perinatal outcome.     

5-Methyl-Tetrahydrofolate and the S-Adenosylmethionine Cycle in C57BL/6J Mouse Tissues: Gender Differences and Effects of Arylamine N-Acetyltransferase-1 Deletion

Folate catabolism involves cleavage of the C⁹-N¹⁰ bond to form p-aminobenzoylgluamate (PABG) and pterin. PABG is then acetylated by human arylamine N-acetyltransferase 1 (NAT1) before excretion in the urine. Mice null for the murine NAT1 homolog (Nat2) show several phenotypes consistent with altered folate homeostasis. However, the exact role of Nat2 in the folate pathway in vivo has not been reported. Here, we examined the effects of Nat2 deletion in male and female mice on the tissue levels of 5-methyl-tetrahydrofolate and the methionine-S-adenosylmethionine cycle. We found significant gender differences in hepatic and renal homocysteine, S-adenosylmethionine and methionine levels consistent with a more active methionine-S-adenosylmethionine cycle in female tissues. In addition, methionine levels were significantly higher in female liver and kidney. PABG was higher in female liver tissue but lower in kidney compared to male tissues. In addition, qPCR of mRNA extracted from liver tissue suggested a significantly lower level of Nat2 expression in female animals. Deletion of Nat2 affected liver 5- methyl-tetrahydrofolate in female mice but had little effect on other components of the methionine-S-adenosylmethionine cycle. No N-acetyl-PABG was observed in any tissues in Nat2 null mice, consistent with the role of Nat2 in PABG acetylation. Surprisingly, tissue PABG levels were similar between wild type and Nat2 null mice. These results show that Nat2 is not required to maintain tissue PABG homeostasis in vivo under normal conditions.     

Special relationships instead of female dominance for redfronted lemurs,Eulemur fulvus rufus

Most lemurs yet studied in detail exhibit some mode of adult female social dominance over males. The known exception, a brown lemur subspecies known as rufous or redfronted lemurs (Eulemur fulvus rufus), forms multimale–multifemale social groups within which unambiguous dominance relations are not observed among adults. Resting groups of redfronted lemurs consistently include huddling adult male–female pairs whose males selectively scentmark and rub their heads in the scentmarks of their female huddling partners. Quantitative observations confirmed that some of these male–female pairs maintain special relationships satisfying all criteria originally developed in research on cercopithecine monkeys. Observations before, during, and after mating season, intergroup encounters, male transfers, and changes in male–female affiliations illuminated developmental and functional aspects of male–female partnerships. Each adult female in two semi-free-ranging study groups shared high rates of association, grooming, and agonistic support and low rates of agonistic interaction with one unrelated or distantly related adult male partner. Such affinity characterized small proportions of adult male–female relationships. Several males directed not only support but also aggression toward adult females with whom they sought to affiliate. All bonded males sought to copulate with their partners, and some appeared to ignore estrus in nonpartners. All females accepted copulation attempts from partners and some seemed to prefer their partners as mates. Partial synchronization of brief estrus periods together with concealed ovulation appeared to minimize chances for polygynous mating. Results support the view that the male–female pair is the fundamental social unit of E. fulvus and suggest that female partnership with individual males obviates dominance behavior, including female dominance, in this lemurid primate. Am. J. Primatol. 43:239–258, 1997. © 1997 Wiley-Liss, Inc.     

Males are cheaper,or the extreme consequence of size/age‐dependent sex allocation: sexist gender diphasy in Fritillaria montana (Liliaceae)

The bulbous geophyte Fritillaria montana is partially self‐compatible and capable of switching gender. Small flowering plants produce only single male flowers, but larger plants produce hermaphrodite or, rarely, male and hermaphrodite flowers. Eight populations in peninsular Italy were sampled to determine the frequency and size distributions of male and hermaphrodite plants, and to determine the relationship of plant size to male and hermaphrodite flower production. Male plants were significantly smaller than hermaphrodites and made up 14.5–47.8% (100% in one small population) of flowering plants within populations. There were no significant differences in male fitness among female‐sterile and hermaphrodite flowers, as they both possessed full and comparable fertilizing power. Therefore, the gender variation observed in F. montana is likely to depend on resource‐dependent sex allocation. From an evolutionary perspective, we highlight the occurrence of similar mechanisms of gender variation in other representatives of the order Liliales. © 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 168 , 323–333.     

Knockout of the Histone Demethylase Kdm3b Decreases Spermatogenesis and Impairs Male Sexual Behaviors

Kdm3b is a JmjC domain-containing histone H3 (H3) demethylase and its physiological functions are largely unknown. In this study, we found that Kdm3b protein is highly expressed in multiple cell types in the mouse testes, including Leydig cells, Sertoli cells, spermatogonia and spermatocytes at different differentiation stages. We also observed Kdm3b protein in the epithelial cells of the caput epididymis, prostate and seminal vesicle. Breeding tests revealed that the number of pups produced by the breeding pairs with Kdm3b knockout (Kdm3bKO) males and wild type (WT) females was reduced 68% because of the decreased number of litters when compared with the breeding pairs with WT males and females. Further analysis demonstrated that Kdm3bKO male mice produced 44% fewer number of mature sperm in their cauda epididymides, displaying significantly reduced sperm motility. No significant differences in the circulating concentration of testosterone and the expression levels of androgen receptor and its representative target genes in the testis were observed. However, the circulating levels of 17β-estradiol, a modulator of sperm maturation and male sexual behaviors, was markedly reduced in Kdm3bKO male mice. Strikingly, abrogation of Kdm3b in male mice significantly increased the latencies to mount, intromit and ejaculate and decreased the number of mounts and intromissions, largely due to their loss of interest in female odors. These findings indicate that Kdm3b is required for normal spermatogenesis and sexual behaviors in male mice.     

On the foraging and feeding ability of Oithona davisae (Crustacea,Copepoda)

Growth experiments with macrophytes revealed anomalies in the growth and development of Najas intermedia. Further analyses showed that these anomalies were caused by differences between the male and female plants. To examine the gender-related differences, the results of two field experiments and a phenological monitoring programme were analysed. The field experiments were conducted in four different lakes in Southern Germany. Over the course of 2 years, eight different sediments were used to research the interaction between the gender and the growth of N. intermedia plants. The phenological monitoring programme, on the other hand, was focused on the development of three different populations of N. intermedia in three Southern German lakes. The results of the experiments revealed significant differences in the gender-related development: Depending on the environmental conditions, male plants grew between 20 and 40% faster than female plants. Additionally, the male plants developed flowers earlier in the vegetation period and died before the female plants. As a result, male and female plants coexisted in the same lake only for a short period of time. This might be a strategy to reduce the competitive pressure between the genders and to gain an advantage over rival species.