Publications (5) View all
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Article: Cryopreservation of human failed maturation oocytes shows that vitrification gives superior outcomes to slow cooling.
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ABSTRACT: This study investigated whether failed maturation oocytes could be used to evaluate different cryopreservation procedures. A total of 289 failed maturation oocytes (GV and MI stages), obtained from 169 patients undergoing IVF treatment (mean age 33.84±5.0) were divided into two different slow-cooling groups (1.5 mol/l 1,2-propanediol+0.2 mol/l sucrose in either NaCl (group A) or choline chloride (ChCl) (group B) based cryopreservation solutions) and one vitrification group (15% ethylene glycol+15% dimethyl sulphoxide). Survival rate, in vitro maturation (IVM) rate, fertilization and developmental rate of cryopreserved oocytes were assessed. Regardless of the stage at which cryopreservation was performed (GV+MI), the slow cooling with ChCl based medium always gave significantly lower survival rate than the slow cooling in NaCl based medium (p=0.01) and vitrification (p<0.001). An extended study also showed statistically reduced survival rate between slow-cooling NaCl based medium and vitrification (p<0.05). Global results of in vitro maturation and fertilization showed worse results between both slow-cooling NaCl and ChCl based media versus vitrification. In conclusion, for oocytes that had failed to mature, vitrification gave better survival, maturation, fertilization and also cleavage rates than the slow-cooling protocols. Four cells embryos were obtained only from vitrified in vitro matured MI oocytes.Cryobiology 12/2010; 61(3):243-7. · 2.06 Impact Factor -
Article: In-vitro maturation of human oocytes: before or after vitrification?
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ABSTRACT: This study aims to determine if in-vitro maturation (IVM) of human immature oocytes should be performed before or after vitrification. A total of 184 immature oocytes were randomly divided into two different groups: 100 were vitrified at metaphase II (MII) stage 24 h-48 h after IVM (group 1) and 84 were immediately vitrified at germinal vesicle (GV) or metaphase I (MI) stages and in vitro matured after warming (group 2). Survival rate after warming was similar in both groups (86.9% versus 84.5%). However, oocyte maturation rate per collected oocyte was significantly higher for oocytes matured before vitrification (group 1, 46%) than for oocytes vitrified before IVM (group 2, 23.8%) (p < 0.01). Consequently, the number of MII oocytes inseminated per oocyte collected was significantly higher for group 1 (40%) than for group 2 (23.8%) (p < 0.05). IVM procedure is more efficient when it is performed before oocyte vitrification.Journal of Assisted Reproduction and Genetics 04/2012; 29(6):507-12. · 1.84 Impact Factor -
Article: Vitrification of in vitro matured oocytes collected from antral follicles at the time of ovarian tissue cryopreservation.
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ABSTRACT: In the past few years, cryopreservation of ovarian tissue has become an established procedure proposed in many centers around the world and transplantation has successfully resulted in full-term pregnancies and deliveries in human. This prospective study aims to evaluate the feasibility of vitrifying in vitro matured oocytes (IVM) isolated at the time of ovarian tissue cryopreservation to improve the efficiency of fertility preservation programs. Oocyte-cumulus complexes were retrieved from freshly collected ovarian cortex by aspirating antral follicular fluid, and were matured in vitro for 24-48 h prior to vitrification. Oocytes were matured in an IVM commercial medium (Copper Surgical, USA) supplemented with 75 mIU/ml FSH and 75 mIU/ml LH and vitrified using a commercial vitrification kit (Irvine Scientific, California) in high security vitrification straws (CryoBioSystem, France). Oocyte collection and IVM rates were evaluated according to the age, the cycle period and the amount of tissue collected. Immature oocyte retrieval from ovarian tissue was carried out in 57 patients between 8 and 35 years of age, undergoing ovarian tissue cryopreservation. A total of 266 oocytes were isolated, 28 of them were degenerated, 200 were at germinal vesicle stage (GV), 35 were in metaphase I (MI) and 3 displayed a visible polar body (MII). The number of oocytes collected was positively correlated with the amount of tissue cryopreserved (p < 0.001) and negatively correlated with the age of the patients (p = 0.005). Oocytes were obtained regardless of menstrual cycle period or contraception. A total maturation rate of 31% was achieved, leading to the vitrification of at least one mature oocyte for half of the cohort. The study showed that a significant number of immature oocytes can be collected from excised ovarian tissue whatever the menstrual cycle phases and the age of the patients, even for prepubertal girls.Reproductive Biology and Endocrinology 11/2011; 9:150. · 2.05 Impact Factor -
Article: Impact of the assessment of early cleavage in a single embryo transfer policy.
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ABSTRACT: The policy of single embryo transfer (SET) adopted for women <36 years old since 1 July 2003, strongly calls for improvement of embryo selection. A total of 196 cycles in which SET was performed were randomly allocated to two groups. In the first group, early cleavage was assessed (ECA) 25 h after insemination. The embryo with the best score that cleaved early, if present, was selected for transfer. In the second group, early cleavage was not assessed (ECNA) and embryo selection was based solely on the embryo score. Ninety-eight cycles were allocated in the ECA and ECNA group respectively. Early cleavage occurred in 64% of cycles and 32.2% of embryos. Patient population and embryo morphology were similar between the two groups, and similar delivery rates were observed (27.6 versus 24.5% respectively in the ECA and ECNA groups). The assessment of early cleavage as additional parameter did not improve the delivery rate in the single embryo transfer policy.Reproductive biomedicine online 08/2006; 13(2):255-60. · 2.04 Impact Factor -
Article: Effect of differential addition of glycerol and pyruvate to extender on cryopreservation of Mediterranean buffalo (B.bubalis) spermatozoa.
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ABSTRACT: The composition of the extender in which semen is diluted before freezing plays a major role in successful cryopreservation of spermatozoa. Substances of high osmolarity, like glycerol, protect sperm cells during the freezing process and energy-rich compounds, like pyruvate provide extra energy during capacitation and fertilization. Since cryopreservation procedures for Buffalo spermatozoa have not been adequately defined, the aim of the study was to improve the survival rate of buffalo (Bubalus bubalis) spermatozoa after cryopreservation by optimizing the timing for adding glycerol and by enriching the cryoprotectant extender with an energy source substrate. Semen was collected with an artificial vagina from 5 bulls and the ejaculates were immediately evaluated for motility, forward progressive motility and for viability, pooled and held at room temperature (28 degrees C) for 1 h. Then aliquots of pooled semen were subjected to dilution and equilibration in triplicate as follows: Experiment 1. Glycerol (3%) in a commercial extender was added to the semen at 28 degrees C and cooled to 5 degrees C for 1 h; then extender with 11% glycerol was added before further equilibration (initial glycerol addition; IGA) and the samples held at 5 degrees C for 1, 3 or 5 additional hours (IGA 1, n = 24; IGA 3, n = 24; IGA 5, n = 24) before freezing. Experiment 2. Glycerol (3%) was added and the mixture brought to 5 degrees C as described above. Then extender with 11% glycerol was added (late glycerol addition; LGA) and after equilibration for 1, 3 and 5 h (LGA 1, n= 24; LGA 3, n = 24; LGA 5, n = 24) the samples were frozen. In Experiments 3 and 4 Na pyruvate (1.25 mM) was added to the extender as described for IGA and LGA above (IPA and LPA samples). The effect of addition time (initial vs late) of glycerol and pyruvate was evaluated by measuring sperm motility, progressively forward motility and viability. After freezing-thawing the percentage of motile spermatozoa was significantly higher (0.001<P<0.01) after a late addition of glycerol and pyruvate (LGA 5 and LPA 5). The optimizing of the timing of the glycerol addition and the presence in the extender of an energy source rendered a higher efficiency in thawed spermatozoa.Theriogenology 08/2000; 54(2):193-207. · 1.96 Impact Factor
