Comparison of the Developmental Potential and Clinical Results of In Vivo Matured Oocytes Cryopreserved with Different Vitrification Media / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Oocyte vitrification is widely used throughout the world, but its clinical efficacy is inconsistent and depends on the vitrification media. This study compared the developmental potential and clinical results of in vivo matured oocytes cryopreserved with different vitrification media.</p><p><b>METHODS</b>This retrospective study involved vitrified-warmed oocytes at one in vitro fertilization laboratory. Vitrification media kits comprised the MC kit (ethylene glycol [EG] plus 1,2-propanediol [PROH]), the KT kit (EG plus dimethyl sulphoxide [DMSO]), and the Modified kit (EG plus DMSO and PROH kit). Rates of oocyte survival and subsequent developmental potential were recorded and analyzed. The t-test and the Chi-square test were used to evaluate each method's efficacy.</p><p><b>RESULTS</b>Oocyte survival rate was significantly higher for the Modified kit (92.0%) than for the MC kit (88.2%) (P < 0.05) and the KT kit (77.3%) (P < 0.001). The rate of high-quality embryo development in the Modified kit group (35.8%) was significantly higher than in the MC kit group (29.0%) and the KT kit group (28.3%) (P < 0.001). No significant differences were observed in the clinical pregnancy and implantation rates among the MC, KT, and Modified kit groups (37.2% vs. 30.2% vs. 39.6%; 21.9% vs. 18.8% vs. 27.4%, respectively) (P > 0.05). The high-quality embryo rate per warmed oocyte was significantly higher (23.4%) in the Modified kit group than in the other groups (P < 0.001). The embryo utilization and live birth rates per warmed oocyte were the highest in the Modified kit group, but not significantly (P > 0.05).</p><p><b>CONCLUSIONS</b>Modified vitrification media are efficient for oocyte vitrification and, with further verification, may be able to replace commercially available media in future clinical applications.</p>

Elective single blastocyst transfer is more suitable for normal responders than for high responders / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Embryo quality and receptivity of the endometrium are two factors that determine the results of in vitro fertilization/intra-cytoplasmic sperm injection-embryo transfer (IVF/ICSI-ET). There is no consensus of the optimal transfer strategy for normal responders or high responders. The current study aimed to find the optimal transfer strategy for different subgroups of patients.</p><p><b>METHODS</b>From April 2010 to December 2010, patients who meet the following criteria were included in this study; primary infertility, female age ≤ 35 years, FSH level on female cycle day 2 - 3 ≤ 12 mIU/ml, at least six good quality embryos available on day three. The clinical outcomes using different transfer strategies between normal responders and high responders were reviewed and compared.</p><p><b>RESULTS</b>For the normal responders, the clinical pregnancy rate of day three double-embryo transfer (DET) was comparable to that of day five elective single blastocyst transfer (eSBT), 64.04% vs. 60.33% (P > 0.05). For the high responders, the clinical pregnancy rate of day five eSBT was significantly lower than that of day three DET, 43.35% vs. 57.21% (P < 0.05). For the high responders, the rates of clinical pregnancy and implantation in frozen-thawed embryo transfer (FET) cycles were notably higher than in eSBT cycles (64.56% vs. 43.35% and 62.11% vs. 43.35% respectively) (P < 0.05).</p><p><b>CONCLUSIONS</b>For normal responders, eSBT might be an applicable strategy to reduce multiple pregnancy rates while maintaining acceptable overall pregnancy rates. And in order to reduce multiple pregnancies and increase the chance of pregnancy of high responders, FET may be a preferable strategy.</p>

Reconstruction of embryo using an improved nuclear transfer method / 生物工程学报

Previous methods used for nuclear transplantation were further investigated to develop a method that was both easy to carryout and did not require any special apparatus, such as Piezoimpact or Spindle-View. Following the puncture of zona pellucida with two holes by injection pipette that contained donor nuclei or cells, the injection pipette was pulled back to the perivitelline space while the negative pressure was increased in the holding pipette until the polar body and karyoplasm were wiped off completely. Then a reconstructed embryo was completed by the direct injection of the donor nucleus or cell without pulling out the injection pipette. 200 oocytes were manipulated using this method and it cost about 40 seconds with nucleus injection and about 30 seconds with cell injection to complete a reconstructed embryo. The success rates were 62.6% and 86. 0%, respectively, and enucleation rate was about 73.3% validated by Hoechst 33342. Using this method, the nucleus was completely eliminated and another was injected using the microscope and micromanipulator. Moreover, the efficiency of nuclear transplantation and survival rate of reconstructed embryos were greatly improved. Furthermore, it is very easy to manipulate and popularize in practice.