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Although several early IVF successes were achieved after transferring fully formed blastocysts, the majority of embryos replaced worldwide over the past 30 years have been at the cleavage stage. The programme at this study centre has previously found that delaying an embryo transfer to day 5 can reduce the chance for a high-order multiple gestation without compromising the pregnancy rate because fewer embryos can be replaced. To evaluate the impact of transfer day and embryonic stage at cryopreservation on cycle outcome, 6069 fresh and 706 frozen transfers from 2000-2006 performed at this study centre were retrospectively analysed. Approximately half of the fresh transfers were performed on day 3, with a shift to day-5 transfer over the study period with no change in cryopreservation incidence. Implantation, clinical pregnancy and live birth rates were significantly higher following day-5 transfer. When frozen-thawed embryos (2-cell to day-6 blastocysts) were transferred, acceptable pregnancy and live birth rates were achieved at all stages but thawed embryos transferred as day-5 blastocysts generated consistently higher clinical pregnancy and live birth rates. Transfer of embryos frozen on day 6 had the highest miscarriage and lowest live birth rates. Barring government regulation, an IVF programme's day for cryopreservation generally depends on its management of and success with fresh embryo transfer.

BACKGROUND: Cytoplasmic defects are thought to cause aneuploidies in oocytes and embryos and oocyte ‘reconstruction’ by germinal vesicle (GV) transfer may circumvent such defects. In mice ‘reconstructed’ oocytes undergo meiosis and fertilize normally, but early embryonic development is compromised if their ooplasm matured in vitro. This study employs sequential MII spindle and/or pronucleus (PN) transfer to assess the embryonic potential of MII nuclei that form following GV transfer. METHODS AND RESULTS: Mouse embryos generated by these procedures were transferred to the oviducts of pseudopregnant mice to monitor pregnancy outcome. Following GV transfer, the resultant metaphase II (MII) nuclei were activated either in situ or transferred and activated in ooplasts from in-vivo matured oocytes. When exchanged with the female PN of a fertilized zygote, only the PNs that developed in in-vivo matured ooplasts generated live offspring. Viable offspring also resulted when MII nuclei were transferred to in-vivo matured ooplasts and fertilized by insemination with sperm or by artificial activation and male PN transfer. Significantly, the offspring displayed normal fertility as adults. CONCLUSION: This report of live births following GV transfer in mice illustrates the importance of the maturational history of the ooplasm at PN formation for normal embryonic and fetal development.

In human embryos, blastomeres differentiate into trophectoderm (TE) cells and inner cell mass (ICM) cells of blastocysts. Although morphologically indistinguishable, blastomeres at early cleavage stages are likely to undergo changes on a molecular level that make them destined to become ICM or TE cells. While the transcription factor Oct-4 might serve as a marker for totipotent ICM cells, human chorionic gonadotrophin might be used as the equivalent for TE cells. This study reports a reverse transcription-polymerase chain reaction procedure to assess human beta-HCG mRNA concentrations as well as ploidy in individual blastomeres from normally and abnormally fertilized human embryos. beta-HCG mRNA was detected in both euploid and aneuploid cells and in oocytes. Surprisingly, beta-LH mRNA was also detected in some euploid blastomeres. In regard to preimplantation genetic diagnosis, assessment of expression levels of beta-HCG and Oct-4 mRNA in individual biopsied cells might serve as a tool to identify embryogenic blastomeres in combination with testing for chromosome and single gene abnormalities.

Objective: To describe different techniques of testicular tissue culture and their effect on sperm motility, mainly in cases of totally immotile spermatozoa, and to compare the effect of in vitro culture with that of motility stimulants. Design: Prospective study. Setting: University teaching hospital. Patient(s): Ten patients undergoing testicular biopsy for diagnostic purposes or for intracytoplasmic sperm injection. Intervention(s): Dissected testicular biopsy samples and tissue blocks were cultured at 37°C for up to 96 hours. Immediately after dissection, immotile testicular spermatozoa were incubated for 30 minutes in pentoxifylline and 2-deoxyadenosine. Main Outcome Measure(s): Sperm motility and vitality. Result(s): Overall, dissected samples showed improved sperm motility, which peaked within 48 hours of culture. Unlike motility, vitality declined linearly, from 56.3% ± 19% at initial assessment to 18.8% ± 11% at 96 hours. Five samples had initially immotile spermatozoa, of which four acquired motility at 48 hours. In vitro culture showed results comparable with those of incubation with pentoxifylline and 2-deoxyadenosine. Culture of tissue blocks did not improve motility or vitality compared with dissected tissue. Conclusion(s): The motility of testicular spermatozoa was enhanced or initiated after in vitro culture. Testicular biopsy culture may be an alternative to the use of motility stimulants to obtain motile spermatozoa for intracytoplasmic sperm injection, particularly when oocytes are not immediately available.

Objective: To look for correlations between acridine orange (AO) staining and semen parameters before and after sperm separation procedures and to assess whether the AO test predicts fertilization or pregnancy outcomes after standard IVF and intracytoplasmic sperm injection. Design: Prospective study that simultaneously assesses sperm morphology and nuclear protein maturity on a cell-by-cell basis before and after preparative procedures. Setting: University teaching hospital. Patient(s): Men (n = 140) undergoing diagnostic semen analysis. Main Outcome Measure(s): Acridine orange fluorescence of sperm nuclei, semen parameters, IVF outcome. Result(s): In unprocessed samples, 90% of sperm with normal heads displayed green fluorescence (mature nuclear protein); significantly lower percentages of green fluorescence were observed in sperm with abnormal heads. The percentage of mature normal sperm in the specimen correlated with motility. Sperm maturity after swim-up or Percoll gradient was significantly improved for sperm with normal or abnormal heads. The percentage of mature normal sperm correlated with motility after either Percoll or swim-up. Neither the percentages of mature nuclei nor mature normal nuclei correlated with fertilization or pregnancy outcome. Conclusion(s): Nuclear protein maturation correlates with sperm motility and morphology. Because morphologically normal and motile sperm are more mature, separation procedures should generate a population of sperm with the highest fertilization capacity. Acridine orange staining, however, did not predict fertilization efficiency or pregnancy outcome in IVF cycles.

This study assessed 1908 embryos, including those with abnormal numbers of pronuclei, in IVF cycles from July 2001 to December 2006 in which preimplantation genetic screening (PGS) was performed on day 3 post-retrieval and ‘euploid’ embryos transferred the following day. PGS-intracytoplasmic sperm injection and PGS-translocation cycles were excluded. At 18 h post-insemination, the zygote distribution was 19% 0PN, 4% 1PN, 69% 2PN and 8% 3PN. No pregnancy occurred following 0PN or 1PN embryo transfers. A retrospective, blinded morphological ranking of all embryos on day 3 was performed and the results compared with PGS; no 0PN or 1PN embryo would have been chosen for transfer based on morphological superiority alone. Blastocyst formation occurred in 1PN embryos (29%) but not in 0PN embryos when evaluated on day 5. Euploid karyotypes were reported for biopsies of 0PN (3%), 1PN (5%) and 2PN (19%) embryos (P = 0.015, 1PN versus 2PN). A Y chromosome was observed in 0PN (17%) and 1PN (32%) embryos; surprisingly, 91% of these Y chromosome-bearing embryos were aneuploid. Many different meiotic and fertilization errors can result in 0PN or 1PN zygotes; these results indicate that the resultant embryos should not be transferred, especially when normally fertilized embryos are available.

In humans, the live birth rate drops precipitously with increasing maternal age, and this decline is associated with increases in the incidence of oocyte and embryo aneuploidy. Preimplantation aneuploidy screening has improved pregnancy outcome by significantly lowering the miscarriage rate. Nevertheless, aneuploidy screening only identifies the affected embryos; it does not attempt to correct the underlying biologic problem. Anomalies in chromosome segregation can result from a dysfunctional first or second meiotic division in the egg or develop after fertilization during the first few mitoses of early embryonic development. In both instances, ooplasmic anomalies may account for the nuclear problem. Low cell levels of cytoplasmic proteins (e.g., cytoskeletal elements, enzymes, energy stores, cell cycle regulatory proteins) may lead to a dysfunctional division of chromosomes during egg maturation or following fertilization. Ooplasmic injection is a micromanipulation technique that has produced pregnancies in patients with a history of poor-quality, fragmented embryos. Germinal vesicle transfer is a research procedure used to investigate the ooplasmic-nuclear interplay regulating cell cycle, maturation, and fertilization. Both these techniques may prove to be effective in improving the quality of eggs from patients of advanced maternal age.

Objective: To compare implantation and pregnancy rates in oocyte recipients undergoing a two-embryo versus three-embryo transfer, 3 days after retrieval. Design: Retrospective comparative analysis. Setting: University-based in vitro fertilization center. Patient(s): All oocyte recipients undergoing embryo transfer from January 1, 1997 through August 31, 1999. Intervention(s): Recipients received two or three embryos. Main Outcome Measure(s): Implantation, and clinical and multiple pregnancy rates. Result(s): Seventy-three recipients underwent a two-embryo transfer, and 376 had three embryos replaced. The numbers of oocytes retrieved (12.7 ± 0.89 vs. 13.1 ± 0.36) and embryos obtained (8.05 ± 0.65 vs. 8.77 ± 0.27) did not differ between the two-embryo and three-embryo transfer groups, nor did the proportion of patients with embryo cryopreservation (54.3% vs. 42.6%, respectively). There was no significant difference in pregnancy or implantation rates when comparing those patients with a two-embryo transfer to those with a three-embryo transfer. Significantly, 13.8% of the pregnancies in the three-embryo transfer group were triplet. Conclusion(s): Reducing the number of embryos transferred in an oocyte donation cycle can lower the incidence of triplet pregnancies without significantly lowering the overall pregnancy rate.

We evaluated whether mouse oocytes reconstructed by germinal vesicle (GV) transfer can develop to blastocyst stage. The oocytes were artificially activated with sequential treatment of A23187 and anisomycin; fertilization was then established by transfer or exchange of pronuclei with those of zygotes fertilized in vivo. Type 1 zygotes were constructed by placing the male haploid pronucleus from a zygote into the cytoplasm of an oocyte that underwent GV transfer, in-vitro maturation and activation; for type 2 zygotes, the female pronucleus was removed from a zygote and replaced with the female pronucleus of an oocyte subjected to GV transfer, in-vitro maturation and activation. Karyotypes of activated oocytes and type 2 zygotes were also subjected to analysis. When cultured in human tubal fluid (HTF) medium, reconstructed oocytes matured and, following artificial activation, consistently developed a pronucleus with a haploid karyotype; the activation rate for this medium was two- to three-fold higher than that of oocytes cultured in M199 (87% versus 30% respectively). Following transfer of a male pronucleus, only 47% of the type 1 zygotes developed to morula or blastocyst stage and embryo morphology was poor. In contrast, 73% of the type 2 zygotes developed to morula or blastocyst stage, many even hatching, with few morphological anomalies. Normal karyotypes were observed in 88% of the type 2 zygotes analysed. These observations demonstrate that the nucleus of a mouse oocyte subjected to sequential nuclear transfer at GV and pronucleus stages is, nonetheless, capable of maturing meiotically, activating normally and supporting embryonic development to hatching blastocyst stage. In contrast, the developmental potential of the cytoplasm of such oocytes appears to be compromised by these procedures.

Objective: To determine whether electrically stimulated Ca 2+ influx can "rescue" fertilization and early embryogenesis in human oocytes that fail to fertilize after intracytoplasmic sperm injection (ICSI). Design: Prospective, randomized trial of a laboratory procedure. Setting: A research laboratory at a university medical center. Patient(s): Discarded oocytes from ICSI-IVF cycles. Intervention(s): Oocytes (n = 104) that showed no evidence of fertilization 16–24 hours after ICSI were assigned to three treatment groups: group 1 (one direct current electrical pulse at 1.36–1.50 kV/cm for 40–60 μs), group 2 (three pulses every 15–20 minutes), or group 3 (treated the same as group 2 but with no electrical stimulation). Main Outcome Measure(s): After stimulation, the oocytes were cultured in vitro for 3–5 days. Oocytes that displayed two pronuclei and a second polar body within 16 hours were considered to have fertilized normally. Fertilization and embryo cleavage rates were compared between groups. Result(s): Fertilization occurred in 26 (70%) of 37 and 38 (78%) of 49 group 1 and 2 oocytes, respectively, but in only 5 (27%) of 18 group 3 oocytes. Within 3 days, group 2 embryos routinely developed beyond the two-cell to four-cell stage (61% versus 13% in group 1); 11% of these oocytes developed to the morula or early blastocyst stage. Sex chromosome analyses indicated 10 male and 8 female embryos. Conclusion(s): Oocytes that fail to fertilize by 24 hours after ICSI can resume apparently normal fertilization and early embryonic development in response to electrical stimulation. Moreover, the degree of cytoplasmic activation as determined by the number of pulses applied affects fertilization efficiency and early embryonic development.

Objective: Leukocytes, predominantly neutrophils, are frequently present in seminal plasma. An increased number of neutrophils (pyospermia) may indicate subclinical urogenital and/or male accessory gland infection. The aim of this study is to determine if the presence of neutrophils correlates with growth of specific type of microorganism(s). Design: A retrospective analysis of semen analysis results from 1999 to 2001 was conducted by the Andrology Laboratory at a large university based IVF program. The study sample comprised of 272 semen samples collected for routine analysis or intrauterine insemination procedure(s). The following specimens were excluded: collection problems, collection off site, and method of collection other than masturbation. Collection guidelines and semen analysis procedures followed WHO (1999) criteria with an acridine orange stain for neutrophils. Measurements were assessed by four andrologists with an intra and inter technician variations 10%. Materials/Methods: Enumeration of neutrophils was performed using two methodologies: peroxidase or acridine orange stain. Similar results were obtained with both procedures. Bacterial cultures were processed by a commercial laboratory (Quest Lab) that used standard culture techniques. Results: The current diagnosis of pyospermia is based upon a threshold of 1 X 106/cc (WHO, 1999). Nonetheless, of these patients with no definable bacteria on culture, 80% were pyospermic. Similarly, of these patients with a positive bacterial culture, 29% had semen PMN levels of 1M/cc. Of the positive cultures, the predominant microorganisms were Staph. epidermidis, Staph. haemolyticus, E. Coli, E. faecalis, a small percentage included Group B Streptococcus. Mean motility did not appear to be influenced by PMN or bacterial status: 52 and 51% for negative bacteria ( and 1M/cc PMNs) and 52 and 50% positive bacteria ( and 1M/cc PMNs) respectively.

Nuclear and pronuclear transfer procedures were used to assess the functional competence of the nucleus and cytoplasm of mouse germinal vesicle-stage oocytes denuded of granulosa cells and matured in vitro or in vivo before artificial activation using a sequential treatment of A23187 1 cycloheximide. Following activation, in vitro-matured oocytes were ‘‘fertilized’’ by inserting a male pronucleus (PN), cultured to the 2-cell stage, and then transferred to the oviducts of foster mothers. No live births were noted, whereas a 17% live birth rate was observed when in vivo-matured oocytes were used. The developmental competency of other zygotes was similarly assessed following the exchange of haploid PN of matured and activated eggs with the female PN of fertilized zygotes. When PN of oocytes subjected to maturation and activation in vitro were transferred, only 1 of 79 reconstructed zygotes developed to term. In contrast, the live birth rate was 21% (11 of 53) for zygotes reconstructed with PN from in vivo-matured oocytes. Moreover, a live birth rate of 23% (8 of 35) was observed for reconstructed zygotes with female PN from ‘‘hybrid’’ oocytes created by transferring the metaphase II nuclei of in vitro-matured oocytes into enucleated, in vivo-matured oocytes before activation. Such results suggest that the nucleus of an in vitro-matured oocyte can support embryonic development, but only when it is activated in the proper ooplasmic milieu. The cellular factors creating this ooplasmic milieu appear to develop normally in vivo during follicle maturation to metaphase II, but they fail to do so when the oocytes are denuded of granulosa cells and cultured in vitro before the final stages of maturation. In parallel studies, male and female PN of in vivo-fertilized zygotes were inserted into oocytes that were activated and enucleated following either in vitro or in vivo maturation. Live birth rates were comparable at 19% (5 of 27) and 18% (9 of 49), respectively, suggesting that, regardless of the environment of the final stages of oocyte maturation, the resultant ooplasm is competent to support all aspects of embryonic development once activation and PN formation has been completed. Such findings only point further toward the importance of the condition of the ooplasmic milieu at the time of chemical activation. Whether a similar situation exists when eggs are activated following sperm penetration remains to be determined. fertilization, gametogenesis, ovum