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Results for “In Vitro Fertilization (IVF)”

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PubMed2003

Pregnancy complications, obstetric risks, and neonatal outcome in singleton and twin pregnancies after GIFT and IVF.

PURPOSE: In vitro fertilization (IVF) and to a lower extent gamete intra-fallopian transfer (GIFT) have become routine infertility treatments in industrialized countries. Our purpose is to compare the obstetric and neonatal characteristics of singleton and twin pregnancies after GIFT and IVF with those conceived spontaneously. METHODS: This case-control study was conducted in a tertiary care medical center. The 322 singleton and 78 twin pregnancies after GIFT or IVF from 1991 through 1996 were evaluated and compared with each other, and with a control group that conceived spontaneously and matched for parity, maternal and gestational age. Statistical significance of differences was assessed by chi(2) test or two-tailed Fisher exact test. Continuous variables were compared by the paired t-test. RESULTS: Pregnancy-induced hypertension (PIH) and vaginal bleeding were significantly more frequent maternal complications in the GIFT/IVF singleton groups compared to controls. In twin pregnancies the rate of cesarean sections, vaginal bleeding and preterm labor were more common after GIFT/IVF but did not reach statistical significance. Assisted reproduction was associated with low birth weight only in twin pregnancies when controlled for confounding variables, however perinatal outcome was comparable. There was no significant difference in the outcome measures between GIFT and IVF pregnancies. CONCLUSION: After controlling for parity, maternal and gestational age, singleton pregnancies conceived by GIFT/IVF are at increased obstetrical risk, however the perinatal outcome is comparable despite a lower average birth weight.

Case-Control Studies↗

PubMed1993

Complete failure of fertilization in couples with unexplained infertility: implications for subsequent in vitro fertilization cycles.

OBJECTIVE: To determine whether complete failure of fertilization of oocytes in couples with unexplained infertility persists during subsequent in vitro fertilization (IVF) cycles. DESIGN: A retrospective study of 120 cycles of IVF in 44 couples with unexplained infertility and complete failure of fertilization during their first IVF trial. SETTING: In vitro fertilization unit of the Sheba Medical Center. PATIENTS: Forty-four couples undergoing IVF for unexplained infertility. MAIN OUTCOME MEASURE(S): Fertilization rate of retrieved oocytes and pregnancy rate. RESULTS: Of the initial 44 couples, 37 underwent additional IVF cycles and 30 (81.1%) achieved fertilization. Seven patients conceived during the study period as a result of IVF and two conceived spontaneously. CONCLUSIONS: Complete failure of fertilization does not necessarily persist during subsequent IVF cycles. Therefore, at least two more IVF cycles should be attempted before reverting to other therapeutic options. However, although fertilization can be achieved in most couples, the mean oocyte fertilization rate during subsequent cycles in this group is low. This suggests an underlying undiagnosed pathology of oocyte/sperm interaction in some of these patients.

Female↗

PubMed1997

The effect of the anaesthetic, Propofol, on in-vitro oocyte maturation, fertilization and cleavage in mice.

Propofol is a common anaesthetic agent used for oocyte retrieval procedures during in-vitro fertilization (IVF). The effect of Propofol in vitro on mouse oocyte maturation, fertilization and embryo cleavage was studied. In this study, 551 cumulus-free and 222 cumulus-enclosed oocytes from mice stimulated with pregnant mare's serum gonadotrophin (PMSG) were incubated for 30 min in medium containing 0, 100, 1000 or 10,000 ng/ml of Propofol prior to in-vitro maturation. Also, 325 cumulus-enclosed oocytes from mice stimulated to ovulate with PMSG/human chorionic gonadotrophin (HCG) were incubated for 30 min in similar concentrations of Propofol prior to IVF. Maturation, fertilization and cleavage rates were compared. A significant decrease in the in-vitro maturation rate was observed only when the cumulus-free and cumulus-enclosed oocytes were exposed to 10,000 ng/ml Propofol (P < 0.0074 and P < 0.0001 respectively). Fertilization and embryo cleavage rates were not significantly different compared with the controls. These findings give some reassurance with respect to human IVF. However, further studies on the potential effects of Propofol on implantation and pregnancy outcome following IVF are needed.

Anesthetics, Intravenous↗

PubMed2006

In vitro production of cat blastocysts of predetermined sex using flow cytometrically sorted semen.

Sex preselection in cats can have applications for both breeding purposes and as an experimental model for endangered felids. The present study examined the ability to produce cat embryos from in vitro fertilization (IVF) of in vitro matured (IVM) cat oocytes with flow cytometrically sorted spermatozoa and to verify the sex of the embryos obtained from sexed spermatozoa by PCR. In the first experiment, a total of 224 oocytes were fertilized with spermatozoa from six ejaculates sorted without sex separation. The sorting process did not influence the cleavage rate (sorted 44.0% versus unsorted 46.1%), day 6 morula-blastocyst rate (sorted 26.6% versus unsorted 29.6%) and day 7 blastocyst rate (sorted 16.5% versus unsorted 16.5%). In the second experiment, a total of 84 IVM oocytes were fertilized with sorted X- and Y-chromosome bearing spermatozoa from four ejaculates in order to obtain embryos of preselected sex. Embryonic sex determination by PCR revealed that 21 out of 24 embryos reaching morula/blastocyst stage (87.5%) were of the desired sex. In particular 12 out of 14 embryos (85.7%) derived from X-bearing spermatozoa were female and 9 embryos out of 10 (90%) derived from Y-bearing spermatozoa were male. Our results show, for the first time, that X- and Y-chromosome bearing spermatozoa sorted by high-speed flow cytometry can be successfully used in an IVM-IVF system to obtain cat embryos of a predetermined sex.

Animals↗

PubMedDate not supplied

[Hormone determination in the management and monitoring of cycles of medically-assisted reproductive technology: value and difficulties of use].

In assisted reproductive technology (ART), serum levels of several key hormones are used to evaluate ovarian follicular reserve and to monitor gonadotropin-stimulated follicle growth. Currently, serum estradiol, FSH, LH and inhibin B levels are examined and combined at the beginning of the menstrual cycle to evaluate the functional status of the ovaries, providing information for appropriate ovarian stimulation treatment and prognosis for in vitro fertilization (IVF) outcome. In women undergoing in vitro fertilization and embryo transfer (IVF-ET), ovulation stimulation is monitored by serial measurements of estradiol, progesterone and LH to monitor follicular growth, evaluate the progression of stimulation, adjust daily gonadotropin therapy for each patient, and predict the optimal day for the induction of ovulation. We analyze the importance of each hormone and discuss the discrepancies frequently reported resulting from differences in methods.

Anti-Mullerian Hormone↗

PubMed1989

[Results of concomitant psychosomatic studies of IVF patients].

The in vitro fertilization (IVF) treatment is very stressful for the couple. The emotional tension (waiting, hoping) plays a greater role than the bodily complaints (stimulation, follicle puncture). Sometimes the wish to get a child is very strong and is the motivation for IVF treatment. Psychological investigations show that IVF patients have fewer psychological complaints compared with other sterility patients; in the psychoanalytically oriented Giessen test there are no differences compared with other sterility patients. The aim of a treatment for IVF patients is the individual, medically and psychologically oriented therapy - sometimes involving the renunciation of a further IVF therapy.

Adaptation, Psychological↗

PubMed2026

Epigenetic safety of in vitro maturation in PCOS: genome-wide DNA methylation profiling of cord blood from a randomized controlled trial.

BACKGROUND: In vitro maturation (IVM) provides a safer alternative to conventional in vitro fertilization (IVF) for women with polycystic ovary syndrome (PCOS) by mitigating the risk of ovarian hyperstimulation. However, concerns persist regarding whether IVM perturbs epigenetic reprogramming in the offspring. Current evidence is constrained by candidate-gene approaches or a lack of parental controls. This study aimed to evaluate the genome-wide DNA methylation safety of IVM compared with conventional IVF using a rigorous trio-based design. METHODS: This secondary epigenetic analysis was nested within a randomized controlled trial (RCT) (ClinicalTrials.gov: NCT03463772). We included 10 nuclear families (trios), comprising five IVM-conceived and five IVF-conceived singleton offspring alongside their biological parents. Both groups utilized a uniform freeze-only single-blastocyst transfer strategy to minimize hormonal confounding. Genomic DNA from umbilical cord blood (UCB) and parental peripheral blood was analyzed using reduced representation bisulfite sequencing (RRBS). Genome-wide methylation patterns and differentially methylated regions (DMRs) were subsequently compared between the groups. RESULTS: Clinical characteristics were comparable between the IVM and IVF groups. Genome-wide analyses demonstrated high concordance in UCB methylation patterns, revealing no significant differences in global CpG methylation levels or distributions across key genomic features (promoters, CpG islands, and gene bodies). Only three rare DMRs were identified in UCB (representing ~ 0.0001% of the genome), none of which mapped to imprinted or developmentally critical loci. Furthermore, methylation variability remained consistent between the groups. CONCLUSIONS: Our findings provide robust mechanistic evidence supporting the epigenetic safety of IVM. The remarkable stability of the neonatal methylome confirms that specific IVM conditions do not compromise early developmental programming, thereby endorsing IVM as a safe and viable alternative for women with PCOS. TRIAL REGISTRATION: ClinicalTrials.gov registry, NCT03463772. Registered on March 13, 2018.

Humans↗

PubMed1996

Toxic effects of ethylene oxide residues on bovine embryos in vitro.

The potential of ethylene oxide (EtO) residues in exposed plastic tissue culture dishes to adversely affect bovine oocyte maturation, fertilization and subsequent embryonic development was monitored. In experiment 1, the effects of aeration time and aeration combined with washing of EtO-gassed culture dishes on the extent of residual toxicity were investigated. There was no cleavage in any treatment in which oocytes were matured and fertilized in dishes exposed to EtO. EtO residues caused functional degeneration of oocytes even when culture dishes were aerated for more than 12 days post EtO-exposure and repeatedly washed. In experiment 2, the residual toxicity of EtO gas on in vitro maturation (IVM), in vitro fertilization (IVF) and in vitro culture (IVC) were evaluated. Cleavage rate significantly decreased and post-cleavage development was retarded in ova maintained in dishes treated with EtO either during IVM or IVF. EtO residues may be more detrimental to spermatozoa than to oocytes which may have been the primary cause of fertilization failure during IVF.

Animals↗

PubMed2002

In vitro maturation, fertilization and development of domestic cat oocytes recovered from ovaries collected at three stages of the reproductive cycle.

This study was conducted to examine the effect of the donor cat's reproductive cycle stage on in vitro maturation (IVM), in vitro fertilization (IVF), and in vitro development of oocytes recovered from ovaries that were collected and stored at 35 degrees C for a short period (1-6 h). Based on the presence or absence of follicles and corpora lutea, the ovarian pairs collected were classified into inactive, follicular, or luteal stages. Nuclear status of 161 cumulus-oocyte complexes (COCs) were examined immediately after recovery; 91.3% of the oocytes were found to be at the immature germinal vesicle (GV) stage, and 3.7% of the oocytes were at metaphase II (MII) stage. The percentage of the oocytes at the GV stage was significantly lower in the follicular stage than in the inactive stage (P < 0.01). Of the oocytes from the follicular stage, 9.1% were at MII stage. After culture for 24 h, however, the proportions of oocytes that reached metaphase I and MII were not different among the reproductive cycle stages of the ovaries collected (P > 0.05). After co-incubation with sperm, 63.1% of oocytes were fertilized, but there were no significant differences among the reproductive cycle stages of the ovaries with respect to the proportions of normal and polyspermic fertilization. However, the number of oocytes reaching cleavage stage and development to the morula and blastocyst stages from follicular stage ovaries were significantly lower (P < 0.05) than those obtained from inactive and luteal stage ovaries. These results indicate that the reproductive cycle stage of donor cat ovaries, stored at 35 degrees C, has no apparent effects on the frequencies of maturation and fertilization of oocytes, but influences developmental competence of the oocytes following IVM or IVF.

Animals↗

PubMed2003

Production of piglets derived from in vitro-produced blastocysts fertilized and cultured in chemically defined media: effects of theophylline, adenosine, and cysteine during in vitro fertilization.

To further develop defined conditions for in vitro fertilization (IVF) and in vitro culture (IVC) of in vitro-matured porcine oocytes, we evaluated the effects of theophylline, adenosine, and cysteine in a chemically defined medium during IVF. Viability to full term of in vitro-produced blastocysts after IVF and IVC in chemically defined medium was also investigated by embryo transfer to recipients. A chemically defined medium, porcine gamate medium (PGM), was modified from porcine zygote medium (PZM-4), which was previously established. PGM was used as a basal medium for IVF and PZM-4 was for the culture of presumptive zygotes. Addition of 2.5 mM theophylline to PGM significantly increased the percentage of male pronuclear formation compared with controls (no addition). Addition of 1 microM adenosine to PGM supplemented either with or without 2.5 mM theophylline significantly reduced the number of penetrated spermatozoa compared with controls (no addition of adenosine). Supplementation with 0.2 microM cysteine in PGM containing both 2.5 mM theophylline and 1 microM adenosine further increased the percentage of development to the blastocyst stage, compared with no supplementation of cysteine, but there was no difference in fertilization parameters, such as monospermy and pronuclear formation, regardless of presence or absence of theophylline and adenosine. When Day 5 blastocysts were transferred into four recipients (20-25 blastocysts per recipient), all recipients became pregnant and farrowed a total of 21 live piglets. The present results clearly demonstrate that porcine blastocysts can be produced by IVF and IVC in chemically defined media and that they can develop to full term after embryo transfer.

Adenosine↗

PubMed1998

Birth of piglets preselected for gender following in vitro fertilization of in vitro matured pig oocytes by X and Y chromosome bearing spermatozoa sorted by high speed flow cytometry.

The present study examined the ability to establish pregnancies after transfer of pig embryos derived from in vitro fertilization (IVF) of in vitro matured (IVM) oocytes by X and Y chromosome-bearing spermatozoa sorted by flow cytometry. Cumulus-oocyte complexes (COC) were cultured in BSA-free NCSU-23 medium containing porcine follicular fluid (10%), cysteine (0.1 mg/mL), epidermal growth factor (10 ng/mL), LH (0.5 microgram/mL) and FSH (0.5 microgram/mL) for 22 h, then the oocytes were cultured without hormonal supplements for an additional 22 h. Boar semen was collected and prepared by flow cytometry sorting of X and Y chromosome bearing spermatozoa. After IVM, cumulus-free oocytes were co-incubated with sorted X or Y spermatozoa (2 x 10(4)/mL) for 6 to 7 h in modified Tris-buffered medium containing 2.5 mM caffeine and 0.4% BSA. After IVF, putative embryos were transferred to NCSU-23 medium containing 0.4% BSA for culture. A portion of the oocytes was fixed 12 h after IVF, the remainder were cultured up to 96 h. At 96 h after IVF, 8-cell to morula stage embryos (n = 30 to 35) from each gender were surgically transferred to the uterus of recipient gilts. Insemination of IVM pig oocytes with X- or Y-bearing sperm cells did not influence the rate of penetration (67 vs 80%), polyspermy (40 vs 53%), male pronuclear formation (95 vs 96%), or mean number of spermatozoa per oocyte (1.6 vs 1.6), respectively. Furthermore, no difference was observed between cleavage rates at 48 h after IVF (X, 49 vs Y, 45%). Transfer of embryos derived from X-bearing spermatozoa to 18 recipients resulted in 5 pregnancies and delivery of 23 females and 1 male piglet. Similarly, transfer of embryos derived from Y-bearing sperm cells to 10 recipients resulted in 3 pregnancies, with 9 male piglets delivered. The results show that X- and Y-bearing spermatozoa sorted using USDA sperm sexing technology can be successfully used in an IVM-IVF system to obtain piglets of a predetermined sex.

Animals↗

PubMed1994

Health and Human Services policy for protection of human subjects research--HHS. Final rule.

The Department of Health and Human Services (HHS) is amending its Human Subjects Protection regulations to rescind the provision requiring prior review and advice from an Ethical Advisory Board for research applications and proposals involving in vitro fertilization (IVF) of human ova as a prerequisite to funding by HHS and its components. The provision was nullified by the National Institutes of Health Revitalization Act of 1993. The regulations are being amended to reflect this statutory nullification. Institutional Review Board (IRB) review and approval of applications and proposals involving in vitro fertilization (IVF) of human ova continues to be required in accordance with other provisions of the Human Subjects Protection regulations. Furthermore, the Secretary may still exercise the option of seeking advice from an Ethical Advisory Board on ethical issues, including IVF, raised by research applications and proposals.

Ethics, Medical↗

PubMed2004

Effects of oxygen tension in the gas atmosphere during in vitro maturation, in vitro fertilization and in vitro culture on the efficiency of in vitro production of mouse embryos.

Effects of oxygen (O2) tension in the gas atmosphere during in vitro maturation (IVM), in vitro fertilization (IVF) and in vitro culture (IVC) on the efficiency of in vitro production of mouse embryos were examined. Mouse oocytes recovered from large antral follicles were subjected to IVM in Waymouth medium for 15, 16 and 17 hr under 5 or 20% O2 and then subjected to IVF and IVC under 5 or 20% O2 tension. Lowering the O2 tension in the gas atmosphere for IVM from 20 to 5% improved the cleavage rate after IVF when the oocytes were subjected to IVM for 15 hr; however, no improvement in the cleavage rate was observed when the culture period for IVM was extended to 16 and 17 hr. Lowering the O2 tension to 5% for IVM and IVC improved the development of the cleaved oocytes to the blastocyst stage, regardless of the culture period for IVM. However, the O2 tension for IVF had no remarkable effect on the subsequent embryonic development. These results demonstrate that 5% O2 is superior to 20% O2 for IVM and IVC, and suggest that 20% O2 for IVM may delay oocyte maturation and/or the acquisition of fertilizability and impair the developmental competence of oocytes.

Animals↗

PubMed2006

Effect of follicular size on in vitro developmental competence of oocytes and viability of embryos after transfer in the dromedary (Camelus dromedarius).

The aim of this work was to determine the effect of follicle size on camel oocyte quality as measured by developmental competence in vitro and in vivo. Ovaries from a local slaughterhouse were dissected to obtain two classes of follicle size: small (3-6 mm) and large (>6 mm) follicles. Quality of the oocytes was assessed after in vitro maturation (IVM), in vitro fertilization (IVF) and in vitro culture (IVC) of cumulus oocyte complexes (COCs). All cultures were done in four replicates at 38.5 degrees C, under 5% CO(2) and high humidity (>95%). Only COCs with cumulus and homogenous (dark) cytoplasm were used. The COCs were matured for 28 h in TCM-199 medium supplemented with 10% heat-treated fetal calf serum (FCS), 10 ng/mL EGF, and 250 microM cysteamine. Nuclear maturation rate for each class of follicle size was determined by contrast phase microscopy in a sample of COCs (n=30) denuded, fixed and stained with aceto-orcein. In vitro fertilization was performed using fresh semen (0.5 x 10(6)spermatozoa/mL in modified TALP-solution). Fertilized oocytes were cultured in mKSOMaa, under 5% O(2) and 90% N(2). The percentage of COCs reaching metaphase II (MII) after 28 h of maturation was 87% (26/30) and 73% (22/30) for oocytes originating from large and small follicles, respectively (P>0.1). The rate of total cleavage (two cells to blastocyst stage) was greater (P<0.05) for oocytes originating from large follicles (72%; 116/162) than for those derived from small follicles (59%; 140/237). The percentage of fertilized oocytes reaching the blastocyst stage was 35% (57/162) and 20% (48/237) for oocytes collected from large and small follicles, respectively (P<0.05). The viability of in vitro-produced hatched blastocyst from the two groups (15 from 3 to 6mm follicle size and 22 from follicles >6 mm) was assessed by transfer to synchronized recipients. None of the hatched blastocysts from small follicles resulted in a pregnancy whereas 68% (15/22) of the transferred hatched embryos from large follicles developed into a 25-day pregnancy. Of the resulting 15 pregnancies, 53% (n=8) aborted (five between 2 and 4 months and three between 5 and 7 months of pregnancy). The remaining seven pregnant females gave birth to normal healthy offsprings (four females and three males). The present study shows that dromedary oocytes developmental competence is acquired late during the final phase of follicular development and this developmental ability translates into greater pregnancy rates after transfer of in vitro produced hatched blastocysts.

Animals↗

PubMed2006

Effects of in vitro maturation of monkey oocytes on their developmental capacity.

The study of in vitro maturation (IVM) of rhesus monkey oocytes has important implications for biomedical research and human infertility treatment. In vitro-matured rhesus monkey oocytes show much less developmental potential than IVM oocytes of other species. Since about 1980 when rhesus monkey IVM, in vitro fertilization (IVF) and in vitro embryo culture (IVC) systems were established, numerous efforts have been made to improve the developmental competence of oocytes and to understand the mechanisms regulating oocyte maturation. This review describes recent progress in this area, particularly the effects of factors such as steroid hormones, energy substrates, amino acids, ovarian follicle status, maternal age and breeding season on the developmental competence, gene expression patterns and genome integrity of rhesus IVM oocytes.

Animals↗

PubMed2004

Effects of culture conditions on IVF outcome.

Although in vitro fertilization (IVF) success rates have improved over the past decade, multiple pregnancies have become a formidable problem. The solution to this problem seems simple by mandating the reduction in numbers of embryos transferred. However, this is typically not accomplished without a compromise in the pregnancy rate. There have been a number of approaches designed to address high order multiple pregnancies from multi factorial analysis of early cleavage stage embryos to the development of extended culture systems, both of which require manipulations in the culture environment. Manipulations in embryo culture environment may not be benign. Several studies have demonstrated that adverse culture conditions have effects on gene expression and imprinting. Studies have also demonstrated that singleton human IVF babies have lower birth weight and higher incidence of congenital anomalies than natural conception babies. All of these factors need to be considered in relation to long term viability of IVF babies and the Barker hypothesis.

Culture Media↗

PubMed1999

Development and viability of bovine preplacentation embryos treated with swainsonine in vitro.

This study investigated the effects of swainsonine (a locoweed toxin) on bovine preplacentation embryo development using in vitro procedures. We examined and confirmed the viability and developmental potential of swainsonine-treated embryos by transfer to synchronized recipient heifers. Oocytes (n = 6338) were aspirated from ovaries collected from the abattoir and subjected to in vitro maturation (IVM), in vitro fertilization (IVF) and in vitro culture (IVC). Swainsonine was added to IVM, IVF, IVC media spatially and IVM/IVF/IVC continuously, at 0 ng/ml (TRTI, control), 200 ng/ml (TRT2), 400 ng/ml (TRT3), and 800 ng/ml (TRT4). Embryo development was evaluated with respect to oocyte cleavage rate and the rates of morula and blastocyst formation. There was no difference (P > 0.05) among treatments. The average number of nuclei per blastocyst at Day 7.5 of culture (Day 0 = IVF) was 85.9 +/- 4.3 (n = 47) and 89.3 +/- 4.4 (n = 44) for swainsonine-treated embryos (800 ng/ml) and control embryos, respectively. Pregnancy rate as determined by ultrasonography on day 35 to 40 post embryo transfer was 43.8% and 38.3% for swainsonine-treated (800 ng/ml) and control embryos, respectively. Nine (9.4%) healthy calves were delivered from heifers receiving swainsonine-exposed and nine (9.6%) from control embryos. No difference (P > 0.05) was detected in number of calves developing from TRT and control embryos. We conclude that swainsonine does not have an adverse effect on the development and viability of preplacentation bovine embryos.

Animals↗

PubMed1993

Effects of electrical stimulation before or after in vitro fertilization on sperm penetration and pronuclear formation of pig oocytes.

The effects of exposure of pig oocytes to an electrical pulse-on sperm penetration and pronuclear formation were determined before or after in vitro fertilization (IVF). After in vitro maturation (IVM) or after collection from oviducts of unmated gilts, pig oocytes either were not exposed or were exposed to an electrical pulse (a 10 sec pulse at 4.0 Vmm-1 AC followed by a 30 microseconds pulse at 120 V mm-1 DC), followed 30 min later by IVF. The incidence of male pronuclear formation of both IVM and in vivo-matured oocytes at 12 hr after insemination was decreased from 59% and 100%, respectively, to 2% and 36%, respectively, by the electrical pulse, but the penetration rates (88-100%) and polyspermic rates (79-100%) were not affected by exposure to an electrical pulse. Similarly, when pig IVM oocytes were exposed to an electrical pulse at 6 hr after insemination, electrical activation did not decrease penetration rates (93% vs. 90%), polyspermic rates (83% vs. 91%), or number of spermatozoa in penetrated oocytes (4.0 +/- 0.5 vs. 4.6 +/- 0.5) but did decrease the rate of male pronuclear formation from 58% to 18%. When oocytes were examined at 6 hr after insemination, 75% of them had been penetrated and resumed meiotic progression, but all sperm heads in penetrated oocytes were fully condensed or only partially decondensed. The percentage of penetrated eggs with multiple female pronuclei was increased when oocytes were exposed to an electrical pulse in all experimental series.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗