Embryo manipulation and imprinting.

As the use of assisted reproductive technologies (ART) continues to rise worldwide, it remains of the upmost importance to maintain the safety of those techniques used in ART. Many of these practices are unique to this discipline; as such, it becomes difficult to assess the true risks that the potential offspring may be subjected to under this type of treatment. Removal of oocytes from a woman's body during an in vitro fertilization (IVF) cycle offers an increased opportunity for routine cellular processes to go awry. Specifically, epigenetic modifications and imprinting diseases are rare among the general population; however, although their incidence among IVF-conceived children is also rare, their frequency in this population remains elevated compared with universal rates. Recent investigations have directly attributed their occurrences to the use of ART and IVF to achieve a successful pregnancy. This review discusses the major cellular manipulations of a typical IVF cycle to assess the potential risks versus the reported risks. These manipulations include preimplantation genetic diagnosis and screening, intracytoplasmic sperm injection, ooplasmic transfer, embryo culture, in vitro maturation, and cryopreservation. Oocyte and embryo handling is a delicate part of the IVF process that continues to improve. The safety of those potential improvements is also discussed.

The effect of semen processing on sperm DNA integrity: comparison of two techniques using the novel Toluidine Blue Assay.

OBJECTIVE: The first goal of this study was to determine the effect that semen processing has on sperm DNA integrity. The second goal was to assess which processing technique (modified swim-up versus density gradient centrifugation) results in a superior sample. DNA integrity was measured using a novel Toluidine Blue Assay. STUDY DESIGN: Side-by-side comparison. MATERIALS AND METHODS: Raw semen samples were collected from thirty-two male individuals and scored for routine semen analysis. Prior to discarding the specimens identical aliquots were divided and processed by density gradient centrifugation and a modified swim-up technique. The Toluidine Blue Assay was used to analyze raw and processed samples. RESULTS: Both density gradient centrifugation and the modified swim-up improved DNA quality compared to the unprocessed sample. However, the modified swim-up technique proved superior. CONCLUSIONS: The swim-up technique generates a sperm sample with better DNA integrity. Should DNA integrity correlate with better pregnancy rates in IUI and IVF, respectively, the swim-up may be the sperm processing technique of choice for these procedures.

Current assessment of sperm DNA integrity.

Conventional semen analysis is rapidly losing its place as the gold standard of diagnosis and the cornerstone of treating the infertile male in modern times. Recent technology allows scientists to analyze sperm fertilizing potential and subsequent embryonic growth by studying factors that have previously escaped traditional parameters. It has become increasingly evident that nuclear DNA arrangement is essential to the fertilizing potential of sperm. A vast array of tests are now available to examine the genetic makeup of individual spermatozoa, ranging the entire gamut from simple bench top assays performed routinely to complex flow cytometric assays requiring highly-skilled technologists. Future research to compare these new tests to those more commonly in use, correlating them with reproductive outcome promises to fill the current void in the field of male infertility, paring innovative diagnostic (and prognostic) technological standards to the already existing sophisticated assortment of successful treatment modalities.