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Contents To date, the only repeatable method to select spermatozoa for chromosomal sex is the Beltsville sorting technology using flow cytometry. Improvement of this technology in the equine species requires increasing awareness of the modifications that the sorting procedure induces on sperm intactness. Oxidative stress is regarded as the major damaging phenomenon, and increasing evidence regards handling of spermatozoa - including sex sorting - as basic ground for oxidative damage. The aim of this study was to disclose whether the flow cytometric sorting procedure increases the production of reactive oxygen species (ROS), and to identify if ROS production relates to DNA damage in sorted spermatozoa using specific flow cytometry-based assays. After sorting, oxidative stress increased from 26% to 33% in pre- and post-incubation controls, to 46% after sex sorting (p < 0.05). Proportions of DNA fragmentation index post-sorting were approximately 10% higher (31.3%); an effect apparently conduced via oxidative DNA damage as revealed by the oxyDNA assay. The probable origin of this increased oxidative stress owes the removal of enough seminal plasma due to the unphysiological sperm extension, alongside a deleterious effect of high pressure on mitochondria during the sorting procedure. [ABSTRACT FROM AUTHOR]

Flow cytometry is considered the only reliable method for the separation of X and Y chromosome bearing spermatozoa in equines. The MoFlo SX DP sorter is highly efficient, allowing the production of foals of the desired sex. However, to achieve acceptable pregnancy rates the currently used protocol requires working with fresh semen obtained close to, or at, the sorting facility. An alternative protocol was tested during two consecutive breeding seasons. Fresh stallion semen was cooled for 20 h, during which staining with Hoechst 33342 took place. On the following day, this sample was flow sorted and compared with spermatozoa from the same ejaculate that had been sexed on the previous day. All sperm parameters evaluated remained unchanged when fresh sorted and refrigerated sorted semen were compared. Pre-sorting storage at 5°C did not alter sperm velocities nor kinetics, viability or membrane permeability, production of reactive oxygen species, mitochondrial membrane potential or DNA fragmentation index of the sorted sample. The findings open for the possibility of using semen from stallions housed far from the sorting facilities. Processed and stained sperm could be shipped refrigerated on the previous day, sorted and inseminated on the next day. [ABSTRACT FROM AUTHOR]

BACKGROUND: International ecological studies have shown a positive association between infant mortality as a proxy for low birth weight and cardiovascular disease mortality in adult life. METHODS: Mortality rates due to Cardiovascular Diseases (CVDMR) standardised by age in adults between 45 and 69years of age and by place of birth (pob) and residence (res) were related to Infant Mortality Rates (IMR) in the Brazilian 1935 birth cohort. RESULTS: Two relationship patterns were noted between IMR and CVDMR: for the Southeast, South and Centre-West group of regions (r(pob)=0.46; r(res)=0.29) and for the North and Northeast group of regions (r(pob)=0.21; r(res)=0.33). For the latter pattern, two states were identified (Rio Grande do Norte and Paraíba) as atypical areas, whose exclusion strengthened the association (r(pob)=0.73; r(res)=0.91). CONCLUSIONS: The direction of the associations changed after the analysis by group of Brazilian regions (indirect control of socio-economic levels, coverage and quality of the information). There is a positive, although weak association between IMR and CVDMR. Attempts to control or minimise the interference of migratory movements, cohort effects and socio-economic levels represented methodological progress in ecological analyses of foetal programming in Brazil. [ABSTRACT FROM AUTHOR]