Aberrant heteroplasmic transmission of mtDNA in cloned pigs arising from double nuclear transfer.

Double nuclear transfer begins with the transfer of nuclear DNA from a donor cell into an enucleated recipient oocyte. This reconstructed oocyte is allowed to develop to the pronuclear stage, where the pronuclei are transferred into an enucleated zygote. This reconstructed zygote is then transferred to a surrogate sow.

Extent of nuclear DNA damage in ejaculated spermatozoa impacts on blastocyst development after in vitro fertilization.

Objective: To determine whether the extent of ongoing apoptotic cell death measured as the presence of DNA strand breaks in spermatozoa affects embryo development to the blastocyst stage in IVF.

Design: A prospective comparative study.

Setting: A university IVF clinic and a private IVF clinic.

The apoptotic profile of human cumulus cells changes with patient age and after exposure to sperm but not in relation to oocyte maturity.

Objective: To determine the expression of apoptosis-associated molecules on cumulus cells removed from individual oocytes of different maturity, inseminated oocytes and to investigate the possibility of an age-dependent expression.

Design: Analysis of apoptosis in cumulus cells isolated from oocytes of different stages of maturity.

Setting: Assisted reproductive technology program of the Birmingham Women's Hospital, Birmingham, UK.

Nature of DNA damage in ejaculated human spermatozoa and the possible involvement of apoptosis.

Numerous studies have shown the presence of DNA strand breaks in human ejaculated spermatozoa. The nature of this nuclear anomaly and its relationship to patient etiology is however poorly understood. The aim of this study was to investigate the relationship between nuclear DNA damage, assessed using the TUNEL assay and a number of key apoptotic markers, including Fas, Bcl-x, and p53, in ejaculated human spermatozoa from men with normal and abnormal semen parameters.