Sound-generating (sonic) motor system in a teleost fish (Porichthys notatus): sexual polymorphisms and general synaptology of sonic motor nucleus

The sonic motor nucleus of the plainfin midshipman, Porichthys notatus, is a midline nucleus located at the junction of the caudal medulla and rostral spinal cord. Its motoneurons innervate sonic "drumming" muscles that are attached to the lateral walls of the swimbladder. There are two classes of sexually mature males referred to as Type I and Type II. The Type I males are larger and generate sounds during the breeding season. The Type II males are smaller and, like adult females, have not yet been shown to generate sounds. This study examined possible sex differences in the size of sonic motoneurons, and the type and distribution of their afferent terminal boutons. The average soma diameter of motoneurons of Type I males is about 50% larger than that of Type II males and females. There is also a small but significant difference in soma diameter between Type II males and females; they are smaller in the former class. There were no sex differences in the presence or distribution of different classes of axosomatic and axodendritic terminal boutons, which included: (1) active zones with either clear, round, or pleomorphic vesicles, (2) active zones with both clear, round vesicles, and larger dense core vesicles, (3) "mixed synapses" with gap junctions and active zones usually associated with pleomorphic vesicles. The results are discussed within the context of sexual differentiation of vertebrate motor systems and the functional organization of the sonic motor system in fishes. Sex differences in soma diameter correlate with a number of sex differences in the gross and ultrastructural features that distinguish the sonic muscles of Type I males from those of Type II males and females, which are similar to each other. The absence of qualitative sex differences in synaptic morphology suggest that the central neuronal circuitry of the sonic motor system is similar among all three adult morphs.     

Keratinocyte-derived growth factors play a role in the formation of hypertrophic scars

In predisposed individuals, wound healing can lead to hypertrophic scar or keloid formation, characterized by an overabundant extracellular matrix. It has recently been shown that hypertrophic scars are accompanied by abnormal keratinocyte differentiation and proliferation, and significantly increased acanthosis, compared with normal scars. This study addressed the question of whether the development of normal and hypertrophic scars is regulated by differences in the growth factor profiles of both the epidermis and the dermis. The presence of interleukin-1alpha (IL-1alpha), IL-1beta, tumour necrosis factor-alpha (TNF-alpha), platelet-derived growth factor (PDGF), transforming growth factor-beta1 (TGF-beta1), and basic fibroblast growth factor (bFGF) was investigated in biopsies taken from breast reduction scars at 3 and 12 months following surgery. The samples were analysed by immunohistological methods and categorized as scars that remained hypertrophic (HH), became normal (HN) or remained normal after 12 months (NN). The epidermal expression of IL-1alpha was significantly increased in NN scars compared with HN and HH scars 3 and 12 months following operation, whereas the dermal expression showed no difference. PDGF was significantly increased in the dermis of normal scars after 3 months and in both the epidermis and the dermis of hypertrophic scars after 12 months. IL-1beta, TNF-alpha, TGF-beta and bFGF showed no differences. It is hypothesized that impaired production of keratinocyte-derived growth factors, such as IL-1alpha, leads to a decrease in the catabolism of the dermal matrix, whereas augmented epidermal PDGF production leads to increased formation of the dermal matrix in hypertrophic scars. These observations support the possibility that the epidermis is involved in preventing the formation of hypertrophic scars.     

The effects of oestrogen therapy on the sex life of post-menopausal women

The literature concerning sexual behaviour around the time of the menopause is reviewed. Mentioned is a decline in sexual activity and satisfaction in women which is attributed to the changes in the women themselves, and not merely a reaction to the decline in the sexual capacity of their husbands.

Forty women were treated during 1 yr with oestrogens. The eventual effect of this treatment on sexual activity and satisfaction was investigated and compared with a group who had undergone partial treatment only. The results show that in the completely treated Group A, symptoms such as hot flushes and depression diminished, and the pain of sexual relations was relieved. As a consequence of this improvement, coital activity and satisfaction were more gratifying. The partially treated Group B showed a clear decline in sexual activity and in sexual satisfaction.     

Effects of anonymity,gender, and erotophilia on the quality of data obtained from self-reports of socially sensitive behaviors

This study examined the effects of anonymity, gender, and erotophilia on the quality of self-reports of socially sensitive health-related behaviors. A sample of 155 male and 203 female undergraduate students was randomly assigned to an anonymous and a confidential (i.e., nonanonymous) assessment condition. Gender, erotophilia, self-reports (of substance use, sexual behaviors, illegal activity), and perceived item threat were assessed by questionnaire. Data quality was strongly affected by experimental condition and gender. Thus, terminations were more frequent in the confidential condition and among women. In the confidential condition, women were significantly more likely to prefer not to respond to sensitive items compared to men. Both female gender and confidential condition were associated with lower frequency reports of sensitive health behaviors, and greater perceived threat of the assessment questions. Self-reported engagement in sensitive behaviors was positively related to both perceived question threat and erotophilia. Path analyses suggest that question threat mediates the effects of anonymity manipulations and gender on data quality (item refusal, termination), and that erotophilia mediates the effects of gender on incidence and frequency self-reports. The results indicate that anonymous assessments as well as male gender are associated with better data quality.     

Genetic variability of sexual behavior in a natural population ofDrosophila melanogaster

Although many experiments on laboratory stocks ofDrosophila have suggested that mate choice is a major feature of sexual selection in this organism, few attempts have been made to measure its extent in wild populations. In this study, a crossing design was used to obtain a set of 13 genetically identical independent lines representative of genotypes from an African population ofDrosophila melanogaster. They were tested for variation in sexual behavior using dyadic tests. Significant variation in orientation and vibration latencies was found for males, and in mating speed and copulation duration for both sexes. No evidence of assortative mating, either positive or negative, was found. The absence of a correlation in mating speed between males and females sharing the same genotype leads us to doubt the applicability of the notion of male eagerness and female reluctancy inDrosophila and the importance of vigor as a factor in mating speed. The absence of mate choice in natural populations ofDrosophila seems to us the most likely hypothesis on the basis of both theory and empirical evidence.     

正常新疆维吾尔族人头发的扫描电镜观察

本文应用扫描电子显微镜对新疆维吾尔自治区南部地区12名(6女,6男),年龄在17岁至20岁之间的维吾尔族人不同部位的头发进行了初步观察研究。发现头发呈圆柱形,毛小皮鳞片呈叠瓦状。但鳞片排列方式、紧密度及形态因个体及部位不同而异。根据毛小皮排列方式可分为三型:即平行型,交错型及混合型,又根据毛小皮排列的紧密度分为密型和疏型。毛干的直径因个体不同大致可分为粗发和细发,粗发毛小皮单位距离内的层数大于细发,毛小皮排列多呈平行线。细发毛小皮排列多呈交错、混合型。     

The relationship between women's subjective and physiological sexual arousal

Previous literature presents discordant results on the relationship between physiological and subjective sexual arousal in women. In this study, the use of hierarchical linear modeling (HLM) revealed a significant concordance between continuous measures of physiological and subjective sexual arousal as assessed during exposure to erotic stimuli in a laboratory setting. We propose that past studies that have found little or no association between the two measures may have been in part limited by the methodology and statistical analyses employed.     

Mutations in raised Drosophila melanogaster affect experience-dependent aspects of sexual behavior in both sexes

Many aspects of the reproductive behavior of Drosophila melanogaster are modified dramatically by experience and age. Males' courtship of immature males and fertilized females decreases over time. Females' receptivity to copulation, and the behaviors that females perform and elicit, are affected by their age and sexual experience. We show that mutations in a raised stock affect all of these age- and experience-dependent aspects of male and female sexual behavior. Experience has no effect on raised males' courtship of immature males and has opposite effects on raised and wild-type males' courtship of fertilized females. In comparison to controls, raised females become sexually mature at an earlier age, and sexually mature raised virgin females copulate more quickly. Following mating, raised females elicit more courtship and remate faster and more frequently than control females.     

Programming life histories: Effects of maternal and environmental variables upon open-field behavior

Open-field behavior was studied as a function of three classes of variables: maternal characteristics, rearing environment, and sexual experience. Mothers of experimental subjects were either handled or nonhandled in infancy. Subjects were born and reared to weaning either in maternit cages or in Hebb-type free environments and were placed after weaning into either a laboratory cage or free enviroment. Sexual experience consisted either of bearing and raising a litter or no sexual experience. The results confirmed previous findings that offspring of mothers handled in infancy arc significantly less active in the open field than the offspring of nonhandled mothers. The maternal handling variable also interacted significantly with breeding experience: for rats which had not been bred, those raised by nonhandled mothers were more active than those raised by handled mothers; for females with breeding experience the reverse was true. Overall, thosc femalcs which had reared a litter were more active and defecated more than their nonbred littermates.