/manager/Index ${session.getAttribute("locale")} 5 Potential importance of transition metals in the induction of DNA damage by sperm preparation media /manager/Repository/uon:18843 50 unselected donors and at least three independent samples were used for each component of the analysis. Participants/Materials, Setting, Methods: The setting was a University biomedical science laboratory. The major techniques employed were: (i) flow cytometry to study reactive oxygen species generation, lipid peroxidation and DNA damage, (ii) computeraided sperm analysis to measure spermmovement and (iii) inductively coupled mass spectrometry to determine the elemental composition of sperm preparation media. Main results and the role of chance: Oxidative DNA damage is induced in spermatozoa prepared on PureSperm discontinuous colloidal silicon gradients (P < 0.001 versus repeated centrifugation) because this medium contains metals, particularly Fe, Al and Cu, which are known to promote free radical generation in the immediate vicinity of DNA. This damage can be significantly accentuated by reducing agents, such as ascorbate (P < 0.001) and inhibited by selective chelation (P < 0.001). This problem is not confined to PureSperm®; analysis of additional commercial sperm preparation media revealed that metal contamination is a relatively constant feature of such products. Limitations, reasons for caution: While the presence of metals, particularly transition metals, may exacerbate the levels of oxidative DNA damage seen in human spermatozoa, the significance of such damage has not yet been tested in suitably powered clinical trials. Wider implications of the findings: The results explain why the preparation of spermatozoa on discontinuous colloidal silicon gradients can result in oxidative DNA damage. The results are of immediate relevance to the development of safe, effective protocols for the preparation of spermatozoa for ART purposes.]]> Sat 24 Mar 2018 08:03:19 AEDT ]]> Egg donor wanted': social work with women looking for an egg donor /manager/Repository/uon:17116 Sat 24 Mar 2018 08:02:29 AEDT ]]>