Effects of neonatal castration and androgenization on sexual dimorphism in bone, leptin and corticosterone secretion

This study investigated the role of neonatal sex steroids in rats on sexual dimorphism in bone, as well as on leptin and corticosterone concentrations throughout the lifespan. Castration of males and androgenization of females were used as models to investigate the role of sex steroids shortly after birth. Newborn Wistar rats were divided into four groups, two male groups and two female groups. Male pups were cryoanesthetized and submitted to castration or sham-operation procedures within 24 h after birth. Female pups received a subcutaneous dose of testosterone propionate (100 mu g) or vehicle. Rats were euthanized at 20, 40, or 120 postnatal days. Body weight was also measured at 20, 40, and 120 days of age, and blood samples and femurs were collected. The length and thickness of the femurs were measured and the areal bone mineral density (areal BMD) was determined by dual-energy X-ray absorptiometry (DEXA). Biomechanical three-point bending testing was used to evaluate bone breaking strength, energy to fracture, and extrinsic stiffness. Blood samples were submitted to a biochemical assay to estimate calcium, phosphorus, alkaline phosphatase, leptin, and corticosterone levels. Weight gain, areal BMD and bone biomechanical properties increased rapidly with respect to age in all groups. In control animals, skeletal sexual dimorphism, leptin concentration, and dimorphic corticosterone concentration patterns were evident after puberty. However, androgen treatment induced changes in growth, areal BMD, and bone mass properties in neonatal animals. In addition, neonatally-castrated males had bone development and mechanical properties similar to those of control females. These results suggest that the exposure to neonatal androgens may represent at least one covariate that mediates dimorphic variation in leptin and corticosterone secretions. The study indicates that manipulation of the androgen environment during the critical period of sexual differentiation of the brain causes long-lasting changes in bone development, as well as serum leptin and corticosterone concentrations. In addition, this study provides useful models for the investigation of bone disorders induced by hypothalamic hypogonadism. (C) 2011 Elsevier Inc. All rights reserved.

Improvement of Older Women's Sexuality Through Emancipatory Education

The purpose of this action research (AR) was to explore the ways in which sexuality is experienced daily and to improve the expression of older women's sexuality. The pedagogy of autonomy as proposed by the Brazilian educator Paulo Freire theoretically supported this AR, with the participation of six older adult women living in a rural setting in southwest Brazil. The older women's experiences regarding sexuality, their concerns, and their educational demands could be summarized through five phrases: the improvement of self-esteem as a way to promote sexuality; sexuality impaired by loneliness and lack of affection; men's sexual satisfaction seen as a woman's obligation; women's sexuality controlled by the society; and relinquishment of the companion to attend to the expectations of family members. Dialogical and participative educational approaches and continuous observation-participation strategies were performed to support the women's care and educational requirements.

Orientação sexual e educação física: sobre a prática pedagógica do professor na escola

Na escola a sexualidade é tópico polêmico, em face da multipicidade de visões, crenças e valores de seus diversos atores. O objetivo desta pesquisa foi investigar como os professores de Educação Física compreendem o papel deste componente curricular no trabalho de orientação sexual nos anos finais do Ensino Fundamental. A metodologia utilizada foi de natureza qualitativa, e a entrevista semiestruturada foi a estratégia escolhida para a coleta dos dados descritivos presentes no discurso dos professores. Os resultados indicaram que a Educação Física congrega elementos importantes ligados à sexualidade, sobretudo ao trabalhar diretamente "com o corpo" e "no corpo", por meio de seus conteúdos. A esse respeito, sugere-se a construção de um currículo escolar no qual o corpo apareça como elemento central na articulação de projetos interdisciplinares, e ressalta-se a necessidade de os professores conhecerem os mecanismos corporais que resultam em bloqueios e dificuldades emocionais ligados à sexualidade.