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Poor-quality medicines are a threat to public health in many low- and middle-income countries, and prospective surveys are needed to inform corrective actions. Therefore, we conducted a cross-sectional survey on a sample of products used for children and available in the private market in Kinshasa, Democratic Republic Congo: amoxicillin (AX) and artemether/lumefantrine (AL), powders for suspension, and paracetamol (PC) tablets 500 mg. Overall, 417 products were covertly purchased from 61 wholesalers. To obtain a representative sample, the products were weighted on their market shares and a subset of 239 samples was randomly extracted to undergo in-depth visual inspection locally, and they were chemically assessed at two accredited laboratories in Belgium. Samples were defined of “poor-quality” if they failed to comply with at least one specification of the International Pharmacopoeia (for AL) or United States Pharmacopoeia 37 (for AX and PC). Results are reported according to the Medicine Quality Assessment Reporting Guideline. The visual inspection detected nonconformities in the aspects of antimalarial powders for suspension, and poor-quality labels across all medicine types. According to chemical analysis, 27.2% samples were of poor quality and 59.5% of AL samples were underdosed in artemether. Poor quality was more frequent for locally manufactured antimalarials (83.3%, P = 0.021; 86.4%, P = 0.022) and PC (4.8%, P = 0.000). The poor quality of the surveyed products may decrease the treatment’s efficacy and favor the development of resistances to antimalarials. It is hoped that these findings may guide the corrective actions of the Democratic Republic of Congo Regulatory Authority, which was the main partner in the research.

BACKGROUND: Partial deletions of the AZFc region of the Y chromosome such as gr/gr deletions have been detected in infertile patients as well as in control groups. The impact of these gr/gr deletions on the etiology of male infertility remains unknown. In the present study, we investigated the presence of gr/gr deletions in Caucasian men. METHODS: gr/gr deletions were analyzed by using markers sY1291, sY1191 and sY1197 and by investigating the presence of single nucleotide variants (SNV) in DAZ and CDY1 genes in patients with azoospermia (n 5 44), cryptozoospermia (n 5 51) or severe oligozoospermia (n 5 92). Control groups consisted of men with normal spermatogenesis on testicular biopsy (n 5 33), normozoospermia (n 5 278) or proven fertility (n 5 83). RESULTS: We observed 20 gr/gr deletions, with eight in infertile patients (4.3%) and 12 in the control groups (3.0%), which was not significantly different. DAZ SNV analysis revealed eight different deletion patterns in patients and controls. CONCLUSIONS: In the present study, no significant differences in the frequency of gr/gr deletions between different patient and control groups were observed. We concluded that the relationship between gr/gr deletions and male infertility remains unclear and that it is too early to systematically test for gr/gr deletions for infertile couples seeking assisted reproduction treatment.

The 'ESHRE Guidelines for Good Practice in IVF Laboratories' were drawn up by the Special Interest Group (SIG) in Embryology and published in the year 2000, and since then they constitute the minimal requirements for any laboratory offering assisted reproduction techniques (ART). In the understanding that the embryologist has a responsibility for the correct and justified application of ART in the laboratory, the implementation of these guidelines requires a quality management programme to be in place that encompasses and integrates the operative units, the processes and procedures that represent the core of ART clinics. In March 2004, the European Parliament issued the Directive 2004/23/EC 'On setting standards of quality and safety for the donation, procurement, testing, processing, preservation, storage and distribution of human tissues and cells'. The Directive applies to human tissues and cells, including fresh or frozen reproductive cells for application to the human body, and is mainly concerned with increasing quality and safety through the implementation of a quality management system. Therefore, the European Society of Human Reproduction and Embryology (ESHRE) undertook a series of initiatives aiming to promote assurance of good laboratory practice and to define the concept of qualified embryologists. One ESHRE initiative was to revise the guidelines for good practice in IVF laboratories, not only in response to the need of embryologists for support and guidance in their duties, but also as a complement to the requirements issued by the Tissue and Cell Directive. The SIG in Embryology hopes that this document may assist the laboratory staff to operate according to the requirements of harmonization, implementation, inspection and certification that are now common to all European member states.

Artificial oocyte activation using the calcium ionophore ionomycin is applied successfully in assisted reproduction but some concern exists on the clinical use. The aims of the present study were to optimize the oocyte activation scheme and to address embryo toxicity in a mouse model. Efficiency of oocyte activation and subsequent development was evaluated and ionomycin was found to be an efficient activator at 10 μmol/l. An improved effect of a second exposure to 5 μmol/l ionomycin on blastocyst development was observed. Toxicity of ionomycin on embryos was then investigated by evaluating pre- and post-implantation development of in-vivo fertilized oocytes following exposure to ionomycin. Blastocyst development, blastocyst cell numbers in trophectoderm and inner cell mass were not different between treated and non-treated zygotes. Also implantation rates and fetal parameters such as length, weight and morphological parameters were similar between the fetuses originating from zygotes treated with ionomycin and non-treated zygotes. Furthermore, healthy offspring originating from ionomycin-treated zygotes was born. In conclusion, no adverse effects of ionomycin on in-vitro or in-vivo mouse embryo development were noticed, giving arguments in favour of the use of ionomycin, although negative long-term effects of this compound cannot be excluded at present.

In vitro-matured germinal vesicle oocytes are an interesting source of cytoplast recipients in both animal and human nuclear transfer (NT) experiments. We investigated two technical aspects that might improve the developmental potential of nuclear transfer mouse embryos constructed from in vitro-matured germinal vesicle oocytes. In a first step, the effect of two maturation media on the embryonic development of NT embryos originating from in vitro-matured oocytes was compared. Supplementation of the oocyte maturation medium with serum and gonadotrophins improved the developmental rate of NT embryos constructed from in vitro-matured oocytes, but it was still inferior to that obtained with in vivo-matured metaphase II (MII) oocytes. Second, we investigated the effect of serial pronuclear transfer from NT zygotes originating from both in vitro- and in vivo-matured oocytes to in vivo-fertilized zygotic cytoplasts. Blastocyst quality was evaluated by counting nuclei from trophectoderm and inner cell mass cells using a differential staining. Sequential pronuclear transfer significantly improved the blastocyst formation rate of NT embryos originating from in vitro-matured oocytes up to the rate obtained with in vivo-matured MII oocytes. We conclude that the developmental potential of NT embryos constructed from in vitro-matured oocytes can be optimized by serial pronuclear transfer to in vivo-produced zygotic cytoplasts.

The effect of simple and sequential embryo culture media on the preimplantation development of mouse nuclear transfer (NT) embryos reconstructed with cumulus cell nuclei using a mechanical NT technique was studied. Blastocyst formation rate was evaluated using CZB medium and the sequential media G1/G2 and KSOM/G2. Arrested two- and three-cell NT embryos were Hoechst-stained to check for nuclear abnormalities. Nonmanipulated and sham-manipulated parthenogenetic embryos served as controls for, respectively, the medium and the handling technique. Rates of blastocyst formation for medium and handling control embryos were similar in CZB (58% and 61%), in G1/G2 (94% and 85%), and in KSOM/G2 (88% and 84%). Development of NT embryos was significantly impaired from the two-cell stage onwards, reaching the blastocyst stage at a rate of 5% in CZB, 14% in G1/G2, and 28% in KSOM/G2. Arrested two- and three-cell stage NT embryos showed a high rate of binucleation. These data demonstrate not only that NT embryos are more sensitive to in vitro culture conditions than parthenogenetic control embryos but also that selection of culture media can influence the preimplantation development of NT embryos.

The objectives of the present study were to achieve 1) oocyte maturation, 2) oocyte competence of fertilization, and 3) oocyte competence of embryogenesis with oocytes from primordial follicles obtained from cryopreserved newborn mouse ovaries by using a two-step method. In the first step, frozen-thawed newborn mouse ovaries were transplanted under the kidney capsule of recipients for the initiation of growth from the primordial follicle stage on. In the second step, growing preantral follicles in the ovarian grafts were recovered and cultured. The results demonstrated that primordial follicles were able to be recruited to preantral follicles during the period of transplantation, and preantral follicles could be mechanically isolated from ovarian grafts. Under the present in vitro culture conditions, 85.8% of the isolated follicles (n = 332) from ovarian grafts survived the 12-day in vitro culture process, 84.9% of the recovered oocytes (n = 285) were germinal vesicle breakdown (GVBD)-competent, and 76% of the oocytes that underwent GVBD (n = 242) developed to the metaphase II (MII) stage. In the in vitro fertilization experiments, 75.4% of 142 inseminated MII oocytes underwent fertilization and cleavage to the 2-cell stage. Subsequently, 79.7% of the 2-cell-stage embryos (n = 69) progressed to the late morula-early blastocyst stage. Transfer of late morula-early blastocyst embryos resulted in the production of live offspring. From our experiments, it may be concluded that in vivo maturation by grafting followed by in vitro maturation of frozen-thawed primordial follicles can restore fertility in mice. This model could be useful for a similar application in the human.

Cryopreservation of ovarian cortical tissue and subsequent transplantation or in vitro culture of follicles are technologies under development with the aim to safeguard fertility in patients with gonadal failure. In the present study, we investigated whether primordial follicles could be triggered to full maturation by a combination of in vivo transplantation and in vitro culture in a mouse model. In a first step, newborn mouse ovaries containing only primordial follicles were allotransplanted under the renal capsule of ovariectomized recipient mice. The second step was to mechanically isolate growing preantral follicles from the graft and culture these in vitro to maturity. In our experiment, one newborn mouse ovary was transplanted under the renal capsule of each 8- to 12-wk-old F1 (C57Bl/6j x CBA/Ca) female ovariectomized recipient (n = 26). Two weeks after transplantation, all 26 grafts were recovered. Four grafts were processed for histology and showed that developmental stages of follicles in 14-day-old ovarian grafts were comparable to those in 14-day-old mouse ovaries. The 22 remaining grafts were used for mechanical isolation of preantral follicles. As a control group, preantral follicles isolated from ovaries of 14-day-old mice were used. The mean preantral follicle yield per ovary was 11 in the transplant group versus 33 in the control group. Follicles were cultured individually in 20-microliter droplets of alpha-MEM supplemented with 100 mIU rFSH and 5% fetal bovine serum for 12 days under an atmosphere of 5% CO(2) in air at 37 degrees C. By Day 12 of culture, 66.5% of follicles retained their oocytes in the grafting group versus 97.5% in the control group (P < 0.001). Final oocyte maturation was induced by addition of 2.5 IU/ml hCG. At 14-16 h post-HCG, the percentages of oocytes showing germinal vesicle breakdown and polar body extrusion were significantly higher in the control group (90.6% and 82.8%) compared to the grafting group (60% and 45%). The mean diameter of the mature oocytes of the grafting group (69.9 +/- 4.45 micrometer) was similar to that of oocytes from the control group (70.5 +/- 2.35 micrometer). Our results suggest that maturation of mouse primordial follicles is feasible by combination of in vivo transplantation and in vitro culture. This two-step strategy may be an attractive model for promoting the growth and maturation of primordial follicles from other species.

This study is a long-term evaluation of the total pregnancy potential of cohorts of fresh and cryopreserved sibling embryos from in-vitro fertilization (IVF) cycles stimulated with either the gonadotrophin-releasing hormone analogue buserelin (BUS) (long protocol) or clomiphene citrate (CC) both in combination with human menopausal gonadotrophin (HMG). Therefore a retrospective analysis was performed on patients who entered the IVF programme between January 1986 and July 1987 and who had triple embryo transfer in the collection cycle. Significantly more fertilized oocytes developed to good-quality embryos in the CC-HMG group (86.1%) than in the BUS-HMG group (80.8%). Transfer of the three morphologically best-looking embryos was performed in day 2 post-insemination in 106 CC-HMG and 80 BUS-HMG cycles. Supernumerary embryos were cultured for a further 24 h and multicellular embryos with up to 20% of fragments were frozen slowly with 1.5 M dimethylsulphoxide on day 3 post-insemination (162 embryos in CC-HMG cycles, 102 embryos in BUS- HMG cycles). Outcome was measured by embryo survival rate, embryo implantation rate and delivery rate in fresh and frozen embryo transfers. Delivery rates were 31.3 and 21.7% per fresh embryo transfer in BUS-HMG and CC- HMG cycles respectively. Fresh embryo implantation rates were significantly higher in collection cycles stimulated with BUS-HMG (17.9%) than in cycles stimulated with CC-HMG (11.3%). Implantation rates were significantly enhanced in embryos transferred in excess of one in cycles leading to pregnancy, perhaps indicative of higher embryo quality in BUS-HMG cycles. Almost all cryopreserved embryos have by now been thawed, so the contribution of frozen embryos to overall pregnancy rates can be evaluated. Overall morphological survival rates of frozen-thawed embryos have by now been thawed, so the contribution of frozen embryos to overall pregnancy rates can be evaluated Overall morphological survival rates of frozen-thawed embryos were similar for 140 embryos from CC-HMG cycles (50%) and 100 embryos from BUS-HMG cycles (46%). The percentage of fully intact embryos was, however, significantly lower in the BUS-HMG group (19%) than in the CC-HMG group (39.5%). Delivery rates were significantly lower following 30 transfers of frozen-thawed embryos from BUS-HMG-stimulated cycles (3.3%) than following 42 transfers of frozen-thawed embryos from CC-HMG cycles (19.1%). Embryo implantation rates were lower for frozen-thawed embryos from BUS-HMG cycles (2.3%) than from CC-HMG cycles (12.7%). Here we demonstrate that ovarian stimulation with the long protocol BUS-HMG instead of the CC-HMG protocol led to higher embryo implantation rates in collection cycles but to lower intact embryo survival rates and to lower embryo implantation rates for frozen sibling embryos. Despite the lower implantation rates with frozen embryos originating from the BUS-HMG protocol, there was no significant difference between total delivery rate per transfer from cycles stimulated with CC-HMG (30.2%) compared with BUS-HMG (33.8%).

OBJECTIVE: To investigate the pregnancy rate of frozen-thawed human supernumerary multicellular embryos that were cryopreserved after intracytoplasmic sperm injection or IVF. DESIGN: A clinical study. SETTING: Consenting patients in an academic research environment. PATIENTS: Couples with severe male infertility, indicated by failed or sporadic fertilization after IVF or subzonal insemination or by

We demonstrated that ovaries removed from female-to-male transsexuals can be used as research material for ovarian cryopreservation, grafting and culture studies. A 21 year old female-to-male transsexual individual, who had been treated with androgens for 12 months, donated her ovaries removed in the sex reversal operation. She had normal numbers of, and proportions of, primordial (98.6%) and primary (1.4%) follicles in her ovarian cortex. After freezing and thawing the ovarian tissue was grafted to immuno-incompetent mice, which were stimulated by human recombinant FSH for 14 days, 10 weeks after transfer. Initiation of growth had occurred in the grafts in which only 79.4% of follicles were primordial, 17.1% primary, and in which there were also secondary and pre-antral follicles. Because long-term androgen treatment does not appear to cause depletion of the primordial follicle pool or affect the developmental capacity of the follicles, ovaries from individuals who undergo sex-reversal operations are an excellent source of tissue for research and maybe even for oocyte donation in the future.

We have studied the effect of 1,2-propanediol (PROH) on cumulus-oocyte complexes from the mouse. We determined the morphological survival rate, the pattern of parthenogenetic activation, and the microtubular and chromosomal organization. Cumulus-oocyte complexes were collected at 16 h post hCG from superovulated female hybrid mice. These cumulus-intact oocytes were exposed to 1.5 or 3 M PROH for 6, 12, or 18 min at 0, 22, or 37 degrees C. The cryoprotectant was diluted out in a 1 M sucrose solution at 22 degrees C. After 5-6 h at 37 degrees C, oocytes were denuded and examined under Nomarski optics. The results show that PROH can induce degeneration and parthenogenetic activation in the mouse oocyte in a concentration, temperature, and time-dependent way. As the activation stimulus was strengthened, an increasing proportion of oocytes shifted from parthenogenetic activation with polar body extrusion to parthenogenetic activation with polar body retention and even to immediate cleavage. Nontoxic and nonactivating conditions involved mainly exposure to 1.5 M PROH at 0 degrees C. Spindle integrity and chromosomal organization were analyzed for exposure to 1.5 and 3 M PROH for 12 min at 0 degrees C. The separate effect of cooling and exposure to 1 M sucrose were also evaluated. Microtubules were visualized by monoclonal anti-alpha-tubulin labeling followed by immunogold-silver staining. Cooling and exposure to 1 M sucrose or to 1.5 M PROH did not induce major abnormalities in the microtubular or chromosomal organization. On the other hand, a significant percentage of deformities such as spindle size reduction and loss of bipolarity were observed after exposure to 3 M PROH. The results of the present study demonstrate that the use of PROH as a single cryoprotectant for the freezing of mature unfertilized oocytes cannot be recommended in procedures involving ambient temperature or concentrations exceeding 1.5 M PROH. On the other hand, the potential beneficial effect of low temperatures may outweigh the effect of concentration at subzero temperatures and could be explored further in the tailoring of conditions for slow controlled freezing.

Background Embryo transfer is a crucial step in the IVF process. Most randomized prospective studies comparing transfer catheters have demonstrated significantly higher pregnancy rates with soft versus firm catheters, but none have taken the operator effect into account. Our aim was to perform a prospective randomized clinical trial comparing two catheters and to study interactions between catheters and operators. Methods A prospective randomized trial comparing the Cook K-SOFT-5100 and Frydman classical catheters 4.5 was performed. Three experienced operators participated in the trial, using a fixed distance transfer protocol. Primary end-point was clinical pregnancy rate, secondary end-points were rates of difficult transfer and of catheter failure. Patients were randomized by a computer program prior to embryo transfer. Results A total of 1446 embryo transfers were performed in 1155 women undergoing IVF or ICSI treatment. A total of 723 cycles were randomized to the Cook catheter and 723 cycles to the Frydman catheter. Following intention-to-treat analysis, the adjusted odds ratio of clinical pregnancy between for the Cook versus the Frydman catheter was 1.11 [95% confidence interval (95% CI) 0.89-1.38]. Odds ratios of clinical pregnancy between the Cook and Frydman catheters for the three operators were respectively 1.19 (95% CI 0.84-1.69), 2.35 (95% CI 1.40-3.95) and 0.69 (95% CI 0.48-0.99). Conclusions Variation in pregnancy rates between embryo transfer catheters depends on variation between operators. Results from randomized clinical trials comparing embryo transfer catheters should not be generalized, because inconsistent conclusions may be unavoidable on the account of different proportions of cycles with transfers by each type of operator. The study was registered at clinicaltrials.gov. NCT00766714.

Objective To determine the presence of mutations in the NXF2 gene of patients with nonobstructive azoospermia. Design Molecular analysis of male infertility. Setting University genetic laboratory and reproductive clinic. Patient(s) Sixty-five patients with Sertoli cell–only syndrome (SCOS) and 20 control men. Intervention(s) Polymerase chain reaction, sequencing analysis, RNA extraction, and reverse transcription polymerase chain reaction. Main Outcome Measure(s) Expression of NXF2 messenger RNA and analysis of the NXF2 gene for the presence of mutations and polymorphisms. Result(s) Messenger RNA derived from the NXF2 gene could be amplified from normal human testicular tissue. Sequencing analysis showed the presence of two polymorphisms in the NXF2 gene. A first alteration, c.1779C>T, was observed in one man who had complete SCOS. Although it is located near an intron–exon boundary, this change probably does not affect splicing. The second alteration, c.1857A>G, was detected in 22 patients with complete SCOS and in 13 patients with incomplete SCOS. Also, 15 of 20 men with normal spermatogenesis had this alteration. Neither of these alterations causes a change at the amino acid level. Conclusion(s) No mutations were detected in the NXF2 gene, from which we concluded that there is no need to screen for mutations in the NXF2 gene in a routine IVF program.

This randomized, controlled trial verifies whether patients with recurrent failed implantation benefit from preimplantation genetic diagnosis for aneuploidy, as compared with conventional assisted reproduction treatment procedures. Two hundred patients with recurrent failed implantation were randomized into two groups. A total of 139 patients underwent ovarian stimulation, and preimplantation genetic screening was performed in 72 patients. Analysis of chromosomes X, Y, 13, 16, 18, 21 and 22 was carried out using fluorescence in-situ hybridization in blastomeres of day-3 cleavage-stage embryos in the study group. The primary endpoint was implantation rate. Secondary endpoints were embryonic morphology and chromosomal status, number of transferred embryos and clinical pregnancy rate. With regard to the implantation rate, there was no significant difference between the study group (21.4%) and the control group (25.3%). The number of embryos transferred was significantly lower in the study group, namely 1.4 (SD 1.0) versus 2.1 (SD 1.0) in the control group (P < 0.05). The clinical pregnancy rate was not significantly different between the groups (25.0% in the study group versus 40.3% in the control group). It can be concluded that preimplantation genetic screening does not increase the implantation rates after IVF-intracytoplasmic sperm injection in women with repeated implantation failure.

OBJECTIVES: To compare the administration of GnRH antagonist in gonadotropin intrauterine insemination (IUI) cycles with cycles where no intervention took place. DESIGN: Meta-analysis of published prospective randomized trials. PATIENTS(S): Five hundred twenty-one patients who were administered a GnRH antagonist and 548 conservatively treated patients who served as control subjects were included in the meta-analysis. INTERVENTION(S): Study selection: Prospective trials were retrieved from Medline and Cochrane Library (last update October 2006). Random effect analysis was used in this meta-analysis. Two independent reviewers performed data extraction. MAIN OUTCOME MEASURE(S): Clinical pregnancy rates. RESULT(S): Six comparisons were retrieved including 1,069 patients. Higher pregnancy rates were found in the randomized controlled trials (odds ratio [OR] 1.56, 95% confidence interval [CI] 1.05-2.33) when a GnRH antagonist was added to a gonadotropin superovulated IUI protocol. Early published studies with smaller sample sizes showed stronger associations (OR 2.31, 95% CI 1.15-4.63) than later studies (OR 1.32, 95% CI 0.79-2.23). CONCLUSION(S): From the randomized controlled trials of this meta-analysis, it is clear that allowing for follicle growth and avoiding premature LH rise, increased pregnancy rates are observed with GnRH antagonist administration. A parallel trend for multiple pregnancy rates in the GnRH antagonist group was observed, although this did not reach statistical significance. The flexible regimen was widely used. This meta-analysis of early data might enhance further research in this direction. Fertil Steril

Objective To submit different glove brands to double-quality control tests using mouse embryo assay (MEA) and the human sperm motility assay (HuSMA). Operator protection against infectious body fluid contamination is a safety issue in assisted reproductive technology (ART). When using gloves in the ART laboratory, toxic substances can be transmitted to culture media, even during brief contact. Design Quality control study of gloves in ART. Setting University hospital-based infertility center. Animal(s) Seven- to 8-week-old female B6D2F1 hybrid mice. Intervention(s) We tested two surgical, two cleanroom, and six examination glove brands. Only gloves brands that passed both HuSMA and MEA were submitted to further QC using zona-free and/or cryopreserved MEA. Main Outcome Measure(s) S perm motility index, two-cell and blastocyst development, blastocyst total cell number. Result(s) Quality control by MEA and HuSMA identified two glove brands to be nontoxic. Conclusion(s) Our study shows that gloves used in ART can be toxic and should be tested as part of an ongoing quality control program.

The use of hormones for controlled ovarian stimulation results in follicular heterogeneity, with oocytes at diverse stages of nuclear and cytoplasmic development. This study evaluated the impact of temporary nuclear arrest by a specific phosphodiesterase 3-inhibitor (PDE3-I), cilostamide, on nuclear and cytoplasmic maturation of cumulus-free germinal vesicle (GV) human oocytes from controlled ovarian stimulated cycles. METHODS: GV oocytes (n = 234) were cultured in: (i) medium without the inhibitor (control); (ii) medium supplemented with 1 microM cilostamide and (iii) medium supplemented with 10 microM cilostamide. Oocytes in groups (ii) and (iii) were exposed to cilostamide for 24 h. The PDE3-I was subsequently removed by transfer of oocytes to fresh in vitro maturation (IVM) medium and the reversibility of GV arrest was assessed during IVM culture for maximum 48 h. RESULTS: Cilostamide (1 and 10 microM) could maintain >80% of the oocytes at the GV stage, without affecting subsequent maturation to metaphase II. Oocytes exposed to 1 microM cilostamide were more likely to have normal bipolar spindles with aligned chromosomes than control oocytes (P

Somatic cloning technology involves the transfer of a somatic cell nucleus into an enucleated oocyte, followed by activation and in vitro culture. Efficiency in terms of live offspring generally remains very low. Little attention has been devoted so far to the impact of culture environment on cloned embryo development. Failure of genomic reprogramming of the donor nucleus in nuclear transfer (NT) experiments could lead to an altered phenotype in these cloned embryos that could be manifested by different medium preferences of the NT embryos. We describe here the application of sequential culture media to support preimplantation development of mouse embryos reconstructed using conventional NT techniques. Embryo-quality analysis was performed on NT blastocysts obtained. Additionally, NT embryos that arrested during development also were analyzed.

BACKGROUND: Single-embryo transfer (SET) has proven efficient in reducing multiple pregnancy rates after assisted reproduction technologies (ART). This study compares outcome of singletons after SET and double-embryo transfer (DET). METHODS: We studied 404 SET and 431 DET patients, who delivered a singleton child of >500 g after fresh embryo transfer in a first, second or third cycle. Preterm birth and low birthweight incidences and gestational age and birthweight were compared between both groups. Adjustments were made for maternal age, parity, cycle rank number, treatment indication, ART method, embryo characteristics and sex of the child. RESULTS: Singletons born after DET have a significantly lower birthweight than that after SET (3204.3 ± 617.5 g versus 3324.6 ± 509.7 g, P < 0.01). Also preterm birth (

Background The aim of our study was to review the results of microsurgically performed testicular sperm extraction (TESE) and to evaluate its possible long term effects on serum testosterone (T). Methods We operated on 48 men (35 +/- 8 years) with non-obstructive azoospermia (NOA). If no spermatozoa were found following a micro epididymal sperm extraction (Silber et al., 1994) and testicular biopsy, testicular microdissection was performed or multiple microsurgical testicular biopsies were taken. The mean follow-up of the serum T was 2.4 +/- 1.1 years. Results Sperm was retrieved in 17/48 (35%) of the men. The per couple take home baby rate if sperm was retrieved was 4/17 (24%). Serum T decreased significantly at follow-up (p < 0.05) and 5/31 (16%) de novo androgen deficiencies developed Conclusion In patients with non-obstructive azoospermia in whom no spermatozoa were found following a micro epididymal sperm aspiration and a simple testicular biopsy, we were able to retrieve spermatozoa in 35% of the men. The take home baby rate was 24% among couples with spermatozoa present upon TESE. De novo androgen deficiency occurred in 16% of the male patients following TESE indicating that, in men with NOA, long term hormonal follow up is recommended after TESE.

BACKGROUND: First-trimester bleeding is frequent in assisted reproductive technique (ART) pregnancies. It is unknown whether first-trimester bleeding, if not ending in a spontaneous abortion, negatively influences further pregnancy outcome in ART in singletons. METHODS: Data were obtained from our ART database (1993–2002), with 1432 singleton ongoing pregnancies being included in this study. The outcome measures—second-trimester and third-trimester bleeding, preterm contraction rates, pregnancy duration, birthweight, Caesarean section rates, intrauterine growth retardation (IUGR), preterm prelabour rupture of membranes (P-PROM), neonatal intensive care unit (NICU) admission and perinatal mortality—were compared in the groups with and without first-trimester bleeding. RESULTS: Significantly more singleton pregnancies resulted from a vanishing twin in the group with firsttrimester bleeding (8.7%) than in the controls (4.0%). A correlation was found between the incidence of first-trimester bleeding and the number of embryos transferred. First-trimester bleeding led to increased second-trimester [odds ratio (OR) = 4.56; confidence interval (CI) = 2.76–7.56] and third-trimester bleeding rates (OR = 2.85; CI = 1.42– 5.73), P-PROM (OR = 2.44; CI = 1.38–4.31), preterm contractions (OR = 2.27; CI = 1.48–3.47) and NICU admissions (OR = 1.75; CI = 1.21–2.54). First-trimester bleeding increased the risk for preterm birth (OR = 1.64; CI = 1.05–2.55) and extreme preterm birth (OR = 3.05; CI = 1.12–8.31). CONCLUSIONS: First-trimester bleeding in an ongoing singleton pregnancy following ART increases the risk for pregnancy complications. The association between firsttrimester bleeding, the number of embryos transferred and adverse pregnancy outcome provides a further argument in favour of single-embryo transfer.

Introduction Pregnancy outcome after IVF has been shown to be worse than after spontaneous conception. There is discussion as to whether this results from the technique itself or the patient characteristics. This study compares pregnancy outcome after IVF and intra-uterine inemination (IUI) in a matched patient group. Methods Data were obtained from our IVF and IUI databases (1997-2001). Matching was performed for maternal age, parity and plurality, and 126 IUI pregnancies were compared with 126 IVF pregnancies. Outcome variables were pregnancy duration, birth weight, Caesarean section rates, preterm contraction rates, neonatal intensive care unit admission, Apgar score, blood loss rates and maternal hypertension. Results None of the analysed parameters was statistically different between the groups. Conclusion This matched case-control study does not show different pregnancy outcomes after IVF and IUI. Since there is no reason to believe that the IUI technique in itself leads to an increased obstetric or neonatal risk, this study suggests that the worse pregnancy outcome after IVF as compared with spontaneous conceptions is due to the specific patient characteristics, rather than to the use of IVF itself.

Background We studied the benefit of using in vitro matured metaphase I (MI) oocytes for ICSI in patients with a maximum of 6 mature metaphase II (MII) oocytes at retrieval. Methods In 2004, 187 ICSI cycles were selected in which maximum 6 MII oocytes and at least one MI oocyte were retrieved. MI oocytes were put in culture to mature until the moment of ICSI, which was performed between 2 to 11 hours after oocyte retrieval (day 0). In exceptional cases, when the patient did not have any mature oocyte at the scheduled time of ICSI, MI oocytes were left to mature overnight and were injected between 19 to 26 hours after retrieval (day 1). Embryos from MI oocytes were chosen for transfer only when no other good quality embryos from MII oocytes were available. Outcome parameters were time period of in vitro maturation (IVM), IVM and fertilization rates, embryo development, clinical pregnancy rates, implantation rates and total MI oocyte utilization rate. Results The overall IVM rate was 43%. IVM oocytes had lower fertilization rates compared to in vivo matured sibling oocytes (52% versus 68%, P < 0.05). The proportion of poor quality embryos was significantly higher in IVM derived oocytes. One pregnancy and live birth was obtained out of 13 transfers of embryos exclusively derived from IVM oocytes. This baby originated from an oocyte that was injected after 22 hrs of IVM. Conclusion Fertilization of in vitro matured MI oocytes can result in normal embryos and pregnancy, making IVM worthwhile, particularly when few MII oocytes are obtained at retrieval.

Oocyte freezing is an established technology but, in contrast to embryo freezing, it has very limited application in clinical IVF programmes. Is there a chance that oocyte freezing will become an integrated routine in assisted reproductive technology? The delicate cytological architecture of the oocyte with a cold-sensitive spindle and a hardening zona have made the frozen oocyte 'unwanted' in assisted reproductive technology. Nevertheless, empirical improvements in freezing protocols and the use of ICSI for fertilization have led to an increasing number of live births. This mitigates against a simple ban on oocyte freezing. While efficiency of oocyte freezing can certainly be further improved by basic research, it is clear that there are humanitarian reasons for considering oocyte freezing as a future fully utilized assisted reproductive technology. The storage of the female genome as a particulate entity can provide an alternative in case of moral, ethical, legal or religious concerns about embryo freezing. Oocyte freezing can also offer hope for oocyte donation and preservation of fertility for women facing ovarian loss. The message is one of cautious optimism when looking for a place for oocyte freezing in routine assisted reproductive technology.

Mouse follicles grown in vitro from preantral to mature stages yield oocytes that can be fertilized in vitro, but embryonic development is poor. To investigate whether this poor development is due to a nuclear or a cytoplasmatic factor, we designed an experiment in which the MII chromosome spindle was exchanged between in vitro-matured oocytes and in vivo-matured oocytes by electrofusion. Subsequent embryo development was evaluated by blastocyst formation rate and blastocyst cell number after parthenogenetic activation. Electrofusion was successful in 62-78% of the oocytes. Transfer of the spindle apparatus from in vitro-matured oocytes to the in vivo MII cytoplasmic environment resulted in a high rate of blastocyst development, whereas in the reverse situation (transfer of the nucleus from in vivo-matured oocytes into in vitro-matured MII cytoplasm) poor quality embryos and a low rate of blastocyst formation was observed. These results indicate that the low developmental competence of in vitro-matured oocytes from mouse preantral follicles after activation is caused by the cytoplasmic component rather than the nuclear component.

Early preantral mouse follicles with a diameter of 110-160 microm were cultured in vitro for 10 or 12 days. Mature oocytes were retrieved following hCG, and fertilization was attempted either by in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI). Two-cell and blastocyst formation rates and blastocyst cell numbers were compared between 10-day and 12-day in vitro-matured oocytes versus in vivo-matured oocytes. Uncleaved IVF oocytes were subjected to chromosome analysis. The 2-cell formation rate was significantly improved by ICSI compared with IVF both in 10-day (72.1% versus 56.1%; P = 0.03) and 12-day cultures (74.1% versus 54.5%; P = 0.028). Cytogenetic analysis of uncleaved MII oocytes following IVF showed that about 30% of MII oocytes showed no sign of sperm penetration. The blastocyst formation rate was significantly lower in 12-day versus 10-day cultures, whether fertilization was by IVF (40.7% versus 62.4%, P = 0.016) or by ICSI (32.5% versus 57.1%, P = 0.035). Blastocyst cell numbers from IVF and ICSI 10-day groups were similar and both significantly higher (P0.001) than from IVF 12-day cultures. All above expressed values were significantly higher for in vivo-matured oocytes. In conclusion, fertilization of oocytes from in vitro-matured mouse preantral follicles can be optimized with ICSI, giving significantly higher 2-cell formation rates than IVF. Blastocyst formation rate was not influenced by the technique of fertilization but rather by the extent of the in vitro culture period. Best results on preimplantation development of oocytes for in vitro-matured preantral follicles were obtained with ICSI on oocytes from 10-day in vitro cultures.

Freezing of mammalian embryos has become part of cryobiology around 30 years ago when the embryologist-cryobiologist team of Whittingham, (1972f>) published for the first time the successful freezing of the mouse embryo leading to the birth of living young. Cryopreservation of the human embryo has entirely been based on experience gained with cryopreservation of mouse embryos. It was in 1983 that the first human pregnancy after transfer of a frozen-thawed eight-cell embryo was announced (1983). At present, freezing of human embryos has become a firmly established adjunct standard routine in clinical programmes of assisted reproduction.

Cryopreserved human primordial follicles grafted into immunodeficient hosts are susceptible to gonadotrophic stimulation but the optimal interval between grafting and stimulation has not been determined. The effect of stimulation with FSH at different time intervals after grafting was therefore investigated. Cryopreserved human ovarian cortical grafts from an androgen pre-treated female-to-male transsexual patient were transplanted into four groups of four non-obese, diabetic severe combined immune deficiency (NOD-SCID) mice. Ten, 12, 14 and 17 weeks after grafting, stimulation was started with daily intra-peritoneal injections of 5 IU of recombinant FSH for 14 days. Grafts were recovered and serially sectioned for counting the number of follicles and determining the different stages of development. Significantly more primary and secondary follicles were found in all stimulated groups compared with the non-stimulated control. This progression from the primordial to growing primary and secondary stages was most significant in the 14 weeks interval group. Formation of antral follicles was scarce and was only noticed in the 10 and 17 week groups. Cystic follicles and follicles with structural oocyte abnormalities were encountered in each group. Whether this phenomenon is related to the hormonal state of the tissue donor or to the cryopreservation and transplantation procedures is the subject of further investigation. It is concluded that the interval between grafting of ovarian tissue and the start of gonadotrophic stimulation may be important for an optimal follicular development after grafting.

Background Ovarian tissue cryopreservation and transplantation can be used to restore fertility to sterile females. A question that warrants further investigation is whether the follicular content is affected by the freeze-thawing and grafting procedure, and if so, to what extent and by what mechanism. Methods and results Intact newborn mouse ovaries were allografted under the kidney capsule or were cryopreserved by slow freezing with dimethylsulphoxide as the cryoprotectant prior to grafting. Estrogenic activity of ovariectomized recipient mice, as revealed by vaginal cytology, resumed after 11 days of transplantation. At 14 days after transplantation, ovarian grafts were recovered and processed histologically for follicle number counting. The follicular content of grafts of fresh ovaries was 58% of that from ovaries of age-matched 14 day old mice. In frozen-thawed ovarian grafts, the follicular content was only 9% lower than that of fresh grafted ovaries. Apoptosis of follicular cells was investigated by DNA nick end labelling. We observed a marked increase in the staining of fragmentation of DNA shortly after transplantation (2-12 h) of fresh newborn mouse ovaries. Conclusions The results of the present study indicate that transplantation rather than cryopreservation accounts for the major and early loss of primordial follicles in grafted newborn mouse ovaries.

Objective : To investigate follicle growth in fresh and cryopreserved human ovarian cortical grafts transplanted to immunodeficient mice. Study design : Fresh or frozen-thawed human ovarian cortex was grafted subcutaneously or under the kidney capsule of 43 mice (35 nude mice and eight SCID mice), 14 of which were non-stimulated controls, 21 injected intra-peritoneally with gonadotrophins during 2 weeks and eight injected during 3 months. Follicle count was compared by Chi-square. Results : Proportions of primordial follicles were significantly lower in grafts than in the tissue before transplantation in gonadotrophin-stimulated mice (37% versus 79%), but not in non-stimulated mice (51% versus 74%). Proportions of primary and secondary follicles were increased after transplantation indicating early follicular growth. One antral follicle was observed in a graft in a mouse stimulated for 3 months. Conclusion : Primordial follicles in fresh or frozen-thawed human ovarian cortex transplanted under the kidney capsule or subcutaneously can grow and are responsive to hormonal stimulation. Condensation : Primordial follicles in fresh and cryopreserved human ovarian cortical grafts can initiate growth after transplantation to immunodeficient mice

Along with improved survival, methods to preserve or restore the fertility potential of young women and children treated with cytotoxic chemotherapy or pelvic radiotherapy have been developed or are in the offing. Surgery, radiotherapy and chemotherapy can all impact on the future ovarian function, but patient and disease tailored application and use of preventive measures can limit ovarian damage. When the loss of reproductive ovarian function is unavoidable, different alternatives to preserve fertility or at least to restore the procreative potential are available. Creation of embryos by IVF, oocyte donation and cryopreservation of mature or immature oocytes are potential issues, the advantages and limitations of which are discussed. Recently, ovarian tissue cryopreservation has spurred interest in the medical literature as well as in the lay press as a method for preservation and restoring fertility. Considering the available data and current state of knowledge, we want to stress that this methodology is still in an experimental phase and we would like to caution against unwarranted enthusiasm of physicians and patients. The medical information preceding the informed consent should mention the actual uncertainties of this method. Moreover, the imperative character of the offer and in particular for paediatric oncological patients, the force of the moral rules that define parental obligations towards children should not be ignored.

Since the first reports of successful pregnancies after treatment with intra cytoplasmic sperm injection (ICSI) in humans, intensive investigations focused on the use of testicular spermatozoa and immature sperm cells in the treatment of azoopsermic patients. Several studies explore the technical development of the preparation, isolation and cryo storage of testicular germ cells. Other studies focus on ICSI itself and try to identify the biochemical and biophysical processes involved in fertilisation after injection of a testicular sperm cell into a human oocyte. Indications for azoospermic patients to whom this first line treatment can be offered are becoming more defined. But one of the major concerns is of course the safety of the technique, especially, for the health and reproductive life of the babies born after application of ICSI with testicular germ cells. An evaluation of ICSI with testicular germ cells is presented in this manuscript.

Objective: To study the effect of delayed intracytoplasmic sperm injection (ICSI) on the fertilization and cleavage of human in vitro matured (IVM) oocytes. Design: Prospective experimental study. Setting: Academic hospital–based fertility center. Patient(s): The experimental group consisted of 73 spare germinal vesicle–stage oocytes from 25 patients. The control group consisted of sibling in vivo matured oocytes from the same patients that were subjected to ICSI in the clinical program. Intervention(s): Equal numbers of sibling IVM oocytes were subjected to ICSI either soon after maturation (30 hours, group 1) or after a 6-hour delay (36 hours, group 2). In a subsequent set of experiments, spermatozoa were labeled with a fluorescent mitochondria–specific vital dye and injected into 17 IVM oocytes that were intentionally aged by 6–8 hours. The resultant zygotes were fixed. Main Outcome Measure(s): Incidence of fertilization and cleavage, numbers and mean diameters of pronuclei, and incidence of zygotes with significant pronucleus size asynchrony. Identification of the male pronucleus by its proximity to the fluorescent sperm midpiece remnant. Result(s): Group 2 had significantly lower rates of normal fertilization (60%) than the control group (82.9%) and significantly lower cleavage rates (46.7%) than both group 1 (85%) and the control group (98.1%). The incidence of oocytes that developed one pronucleus and pronucleus size asynchrony was significantly higher in group 2 (32% and 40%, respectively) than in group 1 (4% and 5%, respectively) and in the control group (4.1% and 4.4%, respectively). All the zygotes with significant pronucleus size asynchrony that developed after delayed ICSI with labeled spermatozoa showed proximity of the fluorescent sperm midpiece remnant to the smaller pronucleus. Conclusion(s): For IVM oocytes, the incidence of one pronucleus, pronucleus size asynchrony (possibly related to a smaller male pronucleus), and cleavage failure increase when ICSI is delayed after maturation. Thus, the timing of ICSI is critical for optimum fertilization of IVM oocytes.

We investigated the effect of duration of exposure at 22 degrees C to a solution containing dimethylsulfoxide (Me2SO), propylene glycol (PROH), and sucrose on the survival rate of one-cell mouse embryos cooled rapidly to -196 degrees C. The cryoprotectant solutions were made up on a molar basis and six different times of exposure were tested (1, 2.5, 5, 10, 15, and 20 min). After rapid thawing and dilution in a 1 M sucrose solution the survival rate was calculated as the number of hatching or hatched blastocysts formed per frozen-thawed and recovered one-cell embryo. We demonstrated that the optimum time of exposure depends on the type of cryoprotectant solution used. The optimum time of exposure was 1 min when a 4.5 M PROH-0.25 M sucrose solution was used, 2.5 min when a 2.25 M PROH-2.25 M Me2SO-0.25 M sucrose solution was used, and 5 min when a 4.5 M Me2SO-0.25 M sucrose solution was used. For prolonged exposure times beyond the optimum, survival rates were the highest when solutions containing 2.25 M PROH-2.25 M Me2SO-0.25 M sucrose were used. To identify factors that may influence the survival rates, we carried out further experiments on one-cell embryos in the different cryoprotectant solutions. We evaluated (i) the survival rates after exposure without freezing and (ii) the volume changes during exposure. It is suggested that the optimum time of exposure to a cryoprotectant solution depends on cryoprotectant permeation and that detrimental effects after prolonged exposure are a consequence of chemical toxicity. When one-cell mouse embryos were exposed for 3 min to a solution containing 2.25 M PROH-2.25 M Me2SO-0.25 M sucrose before rapid cooling to -196 degrees C, 98% of the zygotes were morphologically intact after rapid thawing. There was no further loss in viability during in vitro culture on after transfer in vivo as compared to unfrozen control embryos.

Objective To investigate the optimal protocol for cryopreservation of human embryos obtained from IVF. Design Prospective randomized study. Setting Consenting patients in an academic research environment. Patients Couples undergoing IVF. Interventions A cohort of 2,220 supernumerary multicellular embryos were obtained from 488 patients who were randomized over slow freezing protocols with dimethylsulfoxide (DMSO, 819 embryos), 1,2-propanediol (699 embryos) or a mixture of DMSO and 1,2-propanediol (702 embryos). A total of 725 embryos have been thawed (DMSO, 232 embryos; 1,2-propanediol, 250 embryos and DMSO and 1,2-propanediol, 243 embryos) for transfer in natural ovarian cycles. Main Outcome Measures Embryo survival rate, embryo implantation rate, clinical pregnancy rate (PR), delivery rate, live-birth rate. Results The embryo survival rate was significantly higher with the DMSO protocol (52.6%) than with the 1,2-propanediol (32.0%) or the DMSO and 1,2-propanediol protocols (34.9%). The clinical PR per thawing cycle was significantly higher in the DMSO protocol (17.2%) than in the 1,2-propanediol protocol (3.9%). The clinical implantation rate per embryo thawed was significantly different between a DMSO-frozen embryo (4.7%) and a 1,2-propanediol-frozen embryo (1.2%). A DMSO and 1,2-propanediol-frozen embryo had a 3.7% chance of implantation. The delivery rate per thawing cycle was significantly higher in the DMSO protocol (12.5%) than in the 1,2-propanediol protocol (2.6%). The live-birth rates per embryo thawed were 3.5%, 0.8%, and 2.9% in the DMSO, 1,2-propanediol, and DMSO and 1,2-propanediol groups, respectively. Conclusion Supernumerary multicellular embryos as presented in daily clinical IVF practice have the highest chance of survival and of implantation after cryopreservation when DMSO has been used.

The present report covers the results of a 26-month period in which 1275 consecutive treatment cycles by intracytoplasmic sperm injection (ICSI) were performed in 919 couples. These couples were afflicted with male factor infertility and had had at least one previous failed conventional in vitro fertilization (IVF) treatment cycle. In other couples, the husband had semen parameters incompatible with conventional IVF or suffered from excretory azoospermia which required microsurgical epididymal sperm aspiration or testicular sperm retrieval. Overall, the 2 pronuclear (PN) fertilization rate was 47.7% per retrieved oocyte-cumulus complex and 66.4% per successfully injected metaphase II oocyte. Embryo transfer was performed in 90.8% of started cycles and 362 clinical pregnancies were recorded, giving a clinical pregnancy rate of 28.4% per started cycle or 31.3% per transfer. In addition, updated results on the outcome of pregnancies after microassisted fertilization are presented. As of 30 August 1994, 416 children have been born. Although 16 major congenital malformations have been observed (3.9%), there appears to be no reason for serious concern as regards the occurrence of major congenital anomalies after ICSI.

We investigated the slow freezing of one-cell mouse embryos with either dimethyl sulfoxide (Me2SO) or 1,2-propanediol (PROH) as the cryoprotectant. One-cell embryos, collected from superovulated C57BL/6J x CBA/Ca females were exposed to 1.5 M solutions of either Me2SO or PROH. The embryos were cooled at 0.3 degrees C/min to temperatures between -10 degrees and -80 degrees C before being plunged into LN2 and then warmed at either 20 degrees C/min or 450 degrees C/min. Survival was expressed as the percentage of hatching or hatched blastocysts per frozen-thawed embryo. When the slow cooling was in 1.5 M PROH, the temperature at which survival rates after slow thawing began to increase was -35 degrees C (52.6 +/- 5.2% survival). For slow cooling in 1.5 M Me2SO this temperature was -50 degrees C (45.0 +/- 2.9% survival). The addition of sucrose to the 1.5 M PROH solution raised the temperature at which survival rates after slow thawing began to increase to -30 degrees C (54.8 +/- 3.7% survival). If slow cooling was stopped at high subzero temperatures, embryos survived better after rapid thawing than slow thawing. If slow cooling was stopped at low subzero temperatures, the survival rate was not dependent on the thawing rate if freezing was done in 1.5 M PROH. When freezing was in Me2SO solutions and to subzero temperatures of -60 degrees and -80 degrees C, slow thawing gave better survival than rapid thawing. The addition of sucrose to the Me2SO freezing solution restored the survival rates at -60 degrees and -80 degrees C. These results indicate that high rates of survival may be obtained from one-cell mouse embryos by a rapid or a slow thawing procedure, as has been found for other developmental stages. The results also indicate that PROH provides superior protection compared to Me2SO against freezing-thawing damage and that the addition of sucrose to the freezing solutions prior to freezing improves the overall survival rates. Embryos that survived freezing and developed in culture implanted and formed normal fetuses at rates similar to those of nonfrozen control embryos (60% vs 68% and 53% vs 58%, respectively.

The cryopreservation of mature metaphase II-stage mouse oocytes is associated with decreased fertilizability, spindle damage, and increased polyploidy. Therefore, we investigated the outcome of cryopreservation of immature germinal vesicle-stage mouse oocytes.Oocytes were punctured from Graafian follicles in primed F1 hybrid mice and were then released into maturation medium containing the meiotic inhibitor dibutyryl cyclic AMP. Both slow and ultrarapid freezing protocols with dimethyl sulfoxide, 1,2-proponediol, or a mixture of both agents were tested. We recorded morphological survival rates, in vitro maturation rates, and two-cell and blastocyst formation rates. Each group of frozen oocytes was compared with both unfrozen germinal vesicle-stage oocytes and metaphase II-stage oocytes.An optimal cryosurvival rate of 78% was reached after ultrarapid freezing with 3 M dimethyl sulfoxide followed by one-step dilution, but a decreased rate of two-cell formation was observed. Freezing with a combination of dimethyl sulfoxide and 1,2-propanediol did not improve this fertilization-decreasing effect. Very low cryosurvival rates after freezing with 1,2-propanediol indicated its inappropriateness for ultrarapid freezing of immature oocytes. The rates of in vitro maturation were equivalent for frozen-thawed and freshly collected germinal vesicle-stage oocytes, independent of the freezing protocol used. We report, nevertheless, as a general characteristic for both slow and ultrarapid freezing of fully grown germinal vesicle-stage oocytes, that the in vitro development up to the blastocyst stage is inhibited despite full nuclear maturation.We report that cryopreservation of immature germinal vesicle-stage oocytes is invariably associated with a low developmental capacity after fertilization. The rate of in vitro nuclear maturation did not equate with developmental competence. This in turn suggests the importance of cytoplasmic maturation for embryonic development.

At ovulation, the mouse oocyte is arrested at metaphase of the second meiotic division. Since microtubules are thermo-and chemosensitive structures, the effects of 1.5 M dimethylsulphoxide and 1.5 M 1,2-propanediol were studied at room temperature on the morphology of the meiotic spindle. Oocytes incubated at 37 degrees C or at room temperature served to estimate the effect of temperature in the experiment. The meiotic spindle was visualized by immunogold-silver staining of microtubules. In the control group at 37 degrees C, 88% of oocytes had normal spindles. After incubation at room temperature for the same time, 89% of oocytes showed abnormal spindles. In the oocytes exposed to dimethyl-sulphoxide or 1,2-propanediol at room temperature a protective effect on spindle morphology could be recognized. Subsequent incubation at 37 degrees C resulted in partial restoration of the observed abnormalities after cooling to room temperature and after exposure to dimethylsulphoxide. Incubation at 37 degrees C after exposure to 1,2-propanediol at room temperature induced spindle absence in the majority of oocytes. Although this latter condition allowed fertilization without increased incidence of ploidy abnormalities, a role for 1,2-propanediol as an activating agent is hypothesized.