954 resultados para Sexual development


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The sexual ratio of Gobiocypris rarus exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 17 beta -estradiol from embryo to sexually mature revealed feminization and overdevelopment of connective tissue in male fish gonad in 2-30 pg/L TCDD concentration range. Daphnia magna was not sensitive to the high dose of TCDD (0.1-1000 ng/ml), but the reproduction of D. magna treated with TCDD decreased after the 8th day. 7-Ethoxyresorufin-O-deethylase (EROD) activities in newly fertilized eggs of G. rarus exposed to TCDD dosage groups (1000-100,000 pg/L) were significantly induced and increased with TCDD concentrations at the early life stage, while no difference was found between low TCDD dosage groups (<100 pg/L), but a good relationship between the EROD activity and the TCDD concentration was observed during a long-term developmental stage. There was a pericardial edema formed in a 2-week yolk-sac at the concentration of 1000 pg/L TCDD. But in the exposure group (2 pg/L TCDD for 120 days), the cell nuclei of hepatocytes was far from the center and packed toward the cell membrane; the cristae of most mitochondria in the cell dropped and collapsed; the rough endoplasmic reticulum broke into fragments; and numerous lipid droplets formed in the cell. (C) 2001 Academic Press.

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Land plant evolution required the generation of a new body plan that could resist the harsher and fluctuating environmental conditions found outside of aquatic environments. Unraveling the genetic basis of plant developmental innovations is not only revealing in terms of an evolutionary point of view, but it is also important for understanding the emergence of agronomically important traits. Comparative genetic studies between basal and modern land plants, both at the genome and trancriptome levels, can help in the generation of hypotheses related to the genetic basis of plant evolutionary development.(...)

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The Physical Disability Sexual and Body Esteem (PDSBE) scale was developed to assess respondents' capacity to feel positive about their sexuality and their body while living with a physical impairment. The current paper presents four studies that were conducted to develop and assess the psychometric properties of the 10 item PDSBE scale. The first study was an exploratory factor analysis involving 348 participants with physical disabilities. The factors were: Sexual Esteem, Attractiveness to Others, and Body Esteem. The second study was a confirmatory factor analysis, with a total of 338 participants. This analysis confirmed the factor structure established in study 1. The third study revealed good test-retest reliability on a total of 47 participants with physical disabilities. The final study was conducted with 748 participants with physical disabilities and showed that the PDSBE had high reliability and good convergent and divergent validity. Mean scores showed that women scored significantly higher than men on the total PDSBE scale and on the Sexual Esteem and Attractiveness to Others subscales. Future applications for the PDSBE scale are discussed.

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The current study evaluated the association between attitudes toward sex, stress, relationship quality, performance anxiety, and sexual dysfunction among 157 men (114 dysfunctional, 43 functional) and 186 women (84 dysfunctional, 102 functional). The results demonstrate that the main factors related to all types of sexual dysfunction among men were attitudes toward sex, conflict in their relationship, and performance anxiety. For women, the main factors related to all types of sexual dysfunction were attitudes toward sex, relationship quality, and performance anxiety. These results demonstrate the central role of performance anxiety in either the development or maintenance of sexual dysfunction among both men and women. Clearly, this is an area that has to be considered in any treatment program for sexual dysfunction. (PsycINFO Database Record (c) 2008 APA, all rights reserve

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The purpose of this study was to examine the relationship between body image and social and sexual functioning. The respondents were 426 men and women from metropolitan and rural Victoria, who ranged in age from 18 to 86 years (mean age = 42.26). Respondents completed measures of attractiveness, body satisfaction, body image importance, body image behaviours, appearance comparison, social physique anxiety, self-esteem, depression, anxiety, and social and sexual functioning. Regression analyses were used to detelmine the prediction of social and sexual functioning by body image variables for men and women of different age groups, beyond the effects of psychological adjustment. The results demonstrated that while there were moderate correlations between body image and sociallsexual functioning variables, many of these relationships were best explained by the shared variance of self-esteem. There were some exceptions, particularly among middle-aged men, which are discussed.

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Purpose: To examine concordance between two self-reported measures of puberty: Sexual Maturatiom Scale (SMS) and Pubertal Developl1!ent Scale (PDS) and their acceptability to adolescents. Methods: Participants of a school-based study in grades 5, 7 and 9 were classified into one of 5 pubertal stages using each method. Results: 2864 students (age 9-16 years) participated. Agreement was moderate for males (K 0.42, 95% CI 0.39,0.45) and females (K 0.57, 95% CI 0.53, 0.61). Concordance within one stage was excellent (females 97%, males 89%), with discrepancies due to females being classified one stage later on the PDS (26%) and males one stage earlier (32%). There were more missing data for the SMS (13%) than the PDS (4%).

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A growing research base supports the predictive validity of actuarial methods of risk assessment with sexual offenders. These methods use clearly defined variables with demonstrated empirical association with re-offending. The advantages of actuarial measures for screening large numbers of offenders quickly and economically are further enhanced when the variables used can be extracted from existing electronic databases. This study reports the results of applying a computerized set of historical variables with a sample of 1,133 male sexual offenders released from prison by the New Zealand Department of Corrections. Area under the curve figures of 0.70-0.78 were obtained over periods of 5 to 15 years, reflecting a significant level of association with sexual recidivism. Detected rates of re-offending across risk levels were comparable to those previously reported for the Static-99. Rates of sexual re-offending by child molesters for all sexual offences and offences against child victims are reported separately.

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In the last thirty years there have been many research studies which have examined the reasons why adolescents and young adults engage in sexual behaviours. Most of these studies have lacked a theoretical basis, Consequently there are many links made between variables, but no consistency across studies, or attempts to develop an underlying theory to explain the results. However, there have been theoretical models developed to explain adolescents’ and young adults’ sexual decision making. Unfortunately, many of these models have not been empirically validated. This thesis attempts to address these deficiencies in the literature by utilising a theory of behaviour and applying it to adolescent and young adult sexual decision making. This theory is the Theory of Planned Behaviour (TPB). Two longitudinal studies were conducted to examine the utility of an adaptation of the TPB to sexual decision making among adolescents and young adults. In the first study 58 adolescent males, aged between 14 years and 18 years participated in a longitudinal study using a questionnaire adapted from the Depth of Sexual Involvement Scale. In the second study, 194 young adults (156 female, 38 male) aged between 18 years and 21 years participated in a similar study. The first study found that intention to engage in behaviour was well predicted, although some of the variables in the model, did not in fact, contribute significantly to the prediction. The prediction of behaviour was less strong than that of intention. Study two found that intention to engage in behaviours was well predicted by the model. However, the degree to which intention led to behaviour was not well predicted. Overall, the results of these studies suggest that the TPB is a good theoretical basis from which to launch a systematic and theoretically informed explanation of adolescent and young adult sexual decision making. However, other factors may need to be added to the model to fully describe the decision making process and accurately predict behaviour. Suggestions are made for future research, as well as interventions that may arise as more knowledge is gathered using this paradigm.

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Interviews with women regarding their experiences of sexual desire informed the development of the Female Sexual Desire Questionnaire. A validation sample of 741 women completed this questionnaire, with six interrelated factors found. These components of sexual desire were labelled: Dyadic Desire, Solitary Desire, Resistance, Positive Relationship, Sexual Self-image, and Concern. The portfolio concludes that a standard evaluation process is needed to assess the effectiveness of men's behaviour change groups (MBCGs), and that such programs should comprise only one component of a comprehensive multifaceted intervention strategy against intimate partner violence (IPV). Four case studies are presented.

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Introduction.Sexual desire is often evaluated as part of a global assessment of female sexual function, which may not comprehensively evaluate the various facets of this experience. There currently exists a need to develop a psychometrically robust desire-specific measure for women.

Aim.  The aim of this study was to develop and validate a desire-specific, self-administered instrument that evaluates the multiple facets of sexual desire and factors influencing this experience for partnered heterosexual women, with or without sexual dysfunction.

Methods.  Preliminary items for inclusion in the Female Sexual Desire Questionnaire (FSDQ) were identified through a literature review and individual interviews with partnered heterosexual women, mostly from Australia. The resulting instrument was completed by a validation sample of 741 women, aged between 18 and 71 years, who were involved in a heterosexual relationship of between 3 months' and 49 years' duration.

Main Outcome Measures.  Exploratory factor analysis was used to refine the FSDQ item content and identify the underlying domain structure. The reliability (internal consistency) and validity (convergent validity) of the FSDQ were also evaluated.

Results.  The final version of the FSDQ consisted of 50 items organized into six domains that characterized the experience of, and factors influencing, sexual desire for heterosexual partnered women: Dyadic Desire, Solitary Desire, Resistance, Positive Relationship, Sexual Self-Image, and Concern. Each domain demonstrated high reliability, as did the overall measure. Evidence of construct validity was ascertained through convergence with the Sexual Desire Inventory and the Hurlbert Index of Sexual Desire. A short-form of the FSDQ, consisting of six items, was also developed.

Conclusions.  The FSDQ is a new reliable and valid multidimensional measure designed specifically for evaluating the facets of, and factors influencing, sexual desire among sexually functional and dysfunctional women who are involved in a heterosexual relationship.

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Sry and Wnt4 cDNAs were individually introduced into the ubiquitously-expressed Rosa26 ( R26) locus by gene targeting in embryonic stem (ES) cells to create a conditional gene expression system in mice. In the targeted alleles, expression of these cDNAs should be blocked by a neomycin resistance selection cassette that is flanked by loxP sites. Transgene expression should be activated after the blocking cassette is deleted by Cre recombinase. ^ To test this conditional expression system, I have bred R26-stop- Sry and R26-stop-Wnt4 heterozygotes with a MisRII-Cre mouse line that expresses Cre in the gonads of both sexes. Analysis of these two types of bigenic heterozygotes indicated that their gonads developed normally like those of wild types. However, one XX R26-Sry/R26-Sry; MisR2-Cre/+ showed epididymis-like structures resembling those of males. In contrast, only normal phenotypes were observed in XY R26-Wnt4/R26-Wnt4; MisR2-Cre /+ mice. To interpret these results, I have tested for Cre recombinase activity by Southern blot and transcription of the Sry and Wnt4 transgenes by RT-PCR. Results showed that bigenic mutants had insufficient activation of the transgenes in their gonads at E12.5 and E13.5. Therefore, the failure to observe mutant phenotypes may have resulted from low activity of MisR2-Cre recombination at the appropriate time. ^ Col2a1-Cre transgenic mice express Cre in differentiating chondrocytes. R26-Wnt4; Col2a1-Cre bigenic heterozygous mice were found to exhibit a dramatic alteration in growth presumably caused by Wnt4 overexpression during chondrogenesis. R26-Wnt4; Col2a1-Cre mice exhibited dwarfism beginning approximately 10 days after birth. In addition, they also had craniofacial abnormalities, and had delayed ossification of the lumbar vertebrate and pelvic bones. Histological analysis of the growth plates of R26-Wnt4; Col2a1-Cre mice revealed less structural organization and a delay in onset of the primary and secondary ossification centers. Molecular studies confirmed that overexpression of Wnt4 causes decreased proliferation and early maturation of chondrocytes. In addition, R26-Wnt4; Col2a1-Cre mice had decreased expression of vascular endothelial growth factor (VEGF), suggesting that defects in vascularization may contribute to the dwarf phenotype. Finally, 9-month-old R26-Wnt4; Col2a1-Cre mice had significantly more fat cells in the marrow cavities of their metaphysis long bones, implying that long-term overexpression of Wnt4may cause bone marrow pathologies. In conclusion, Wnt4 was activated by Col2a1-Cre recombinase and was overexpressed in the growth plate, resulting in aberrant proliferation and differentiation of chondrocytes, and ultimately leads to dwarfism in mice. ^

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This study described the relationship of sexual maturation and blood pressure in a sample (n = 361) of white females, ages seven through 18, attending public schools in a defined area of Central Texas during October through December, 1984. Other correlates of blood pressure were also described for this sample.^ A survey was performed to obtain the data on height, weight, body mass, pulse rate, upper arm circumference and length, and blood pressure. Each subject self-assessed her secondary sex characteristics (breast and pubic hair) according to drawings of the Tanner stages of maturation. The subjects were interviewed to obtain data on personal health habits and menstrual status. Student age, ethnic group and place of residence were abstracted from school records. Parents or guardians of the subjects responded to a questionnaire pertaining to parental and subject health history and parents' occupation and educational attainment.^ In the simple linear regression analysis, sexual maturation and variables of body size were significantly (p < 0.001) and positively associated with systolic and fourth- and fifth-phase diastolic blood pressure. The demographic and socioeconomic variables were not sufficiently variant in this population to have differential effects on the relation between blood pressure and maturation. Stepwise multiple regression was used to assess the contribution of sexual maturation to the variance of blood pressure after accounting for the variables of body size. Sexual maturation (breast stage) along with weight, height and body mass remained in the multiple regression models for fourth- and fifth-phase diastolic blood pressure. Only height and body mass remained in the regression model for systolic blood pressure; sexual maturation did not contribute more to the explanation of the systolic blood pressure variance.^ The association of sexual maturation with blood pressure level was established in this sample of young white females. More research is needed first, to determine if this relationship prevails in other populations of young females, and second, to determine the relationship of sexual maturation sequence and change with the change of blood pressure during childhood and adolescence. ^