Publications (5)14.04 Total impact

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    ABSTRACT: Only 50-60 % of immature human oocytes attain the mature stage in vitro. Such a deficiency may be a reflection of inadequate conditions of in vitro maturation (IVM) or a manifestation of intrinsic oocyte defects. In the present study, we explored the possibility that the DNA of immature oocytes may be damaged and that such a condition, or inability to trigger a repair action, is associated to germinal vesicle (GV) arrest. Immature oocytes (GV-stage oocytes) were obtained from women undergoing stimulated (Stim-C) or IVM (IVM-C) cycles. GV oocytes obtained from stimulated cycles were fixed for successive analysis either after recovery (T0) or following 30 h (T30) of culture if still arrested at the GV stage. Oocytes retrieved in IVM cycles were used only if they were found arrested at the GV stage after 30 h (T30) of culture. All oocytes were fixed and stained to detect chromatin and actin. They were also assessed for positivity to γH2AX and Rad51, markers revealing the presence of double-strand DNA breaks and the activation of a DNA repair response, respectively. Labelled oocytes were analysed using a Leica TCS SP2 laser scanning confocal microscope. In Stim-C oocytes, γH2AX positivity was 47.5 and 81.5 % in the T0 and T30 groups, respectively (P = 0.003), while γH2AX-positive oocytes were 58.3 % in the IVM-C T30 group (Stim-C T0 vs. IVM-C T30, P = 0.178; Stim-C T30 vs. IVM-C T30, P = 0.035). Positivity for nuclear staining to Rad51 occurred in 42.1 and 74.1 % of Stim-C in the T0 and T30 subgroups, respectively (T = 0.006), while 66.7 % of IVM-C T30 oocytes resulted positive for a DNA repair response (Stim-C T0 vs. IVM-C T30, P = 0.010; Stim-C T30 vs. IVM-C T30, P = 0.345). The present data document the existence of double-strand DNA breaks (DSBs) in human immature oocytes. Also, they are consistent with the hypothesis that insults to DNA integrity may be an important factor affecting meiotic resumption.
    No preview · Article · Aug 2015 · Journal of Assisted Reproduction and Genetics
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    ABSTRACT: To assess retrospectively the developmental potential of different types of cumulus cell-oocyte complexes (COCs) derived from IVM cycles. IVM cycles were performed in natural cycles or after HCG, FSH, or FSH/HCG priming. COCs recovered were morphologically characterized in different types: compact (CC) or expanded (EC) cumulus mass but including an immature oocyte, and expanded cumulus mass enclosing a mature oocyte (EC-MII). Embryo developmental competence was investigated analysing exclusively cycles in which all transferred embryos derived from the same COC category. Fertilization rates did not differ significantly. Significant differences in pregnancy rates (14.5%, 10.0% and 27.6 % in the CC, EC, and EC-MII categories, respectively) were observed. Likewise, significant differences in implantation rates (8.9%, 6.3% and 19.1% in the CC, EC, and EC-MII categories, respectively) were found. Overall, priming with FSH/HCG had a beneficial effect on pregnancy and implantation rates, while no priming or HCG alone generated oocytes with poor competence. In IVM cycles, morphological evaluation at the time of collection can predict the developmental ability of different COCs. FSH/HGC priming has a positive effect on oocyte competence.
    Full-text · Article · Apr 2012 · Journal of Assisted Reproduction and Genetics

  • No preview · Conference Paper · Jan 2012
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    Article: EMBRYOLOGY
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    ABSTRACT: Introduction: In order to optimize IVF/ICSI treatments it is important that embryos are scored uniformly by different people working in the same laboratory. Lab to lab standardisation for embryo morphological assessment is important for the comparison of results and for doing research. To minimize the inter observer variability, there is a need of internal and external quality control. This gives participants the possibility to compare their own assessment with colleagues or even with embryologists and lab technicians from other institutions. To improve standardization for embryo morphological assessment, we started a survey among embryologists and lab technicians of Dutch IVF centers, followed by more embryologists and lab technicians from all over the world. This survey was conducted to measure the inter-observer variability in embryo score and embryo selection. All participants assessed the same embryo video fragment. Material and Methods: In December 2009 mainly Dutch IVF professionals were invited to participate to the quarterly surveys at Afterwards, more embryologists and lab technicians from all over the world joined the survey. The number of registered participants was 70 in January 2010 and increased to 170 in October 2011; the percentage of active participants was about 60% (range 48- 90% per survey). The participants are employed in more than 60 different institutions. Only Dutch centers have multiple participants per laboratory, giving the possibility to compare intra-laboratory results and measure the variability amongst colleagues within a laboratory. 40 video fragments of single transferred embryos were scored during the last 2 years, distributed in 8 survey’s, one survey every three months. Each survey consisted of 5 video-fragments (day 3 or day 2 embryos). Each video-fragment contained 7 shots at 7 planes of an embryo: one in the middle, three under and three above the middle plane. Embryos were scored by use of 2 parameters: cell number (from 2 to 10 cells or morula) and gradation according to the most widely used system in the Netherlands: grade 1: blastomeres of equal size, no fragmentation; grade 2: blastomeres of unequal size, <10% cytoplasmic fragments or granular blastomeres; grade 3: blastomeres of unequal size, 10-50% cytoplasmic fragments and granular blastomeres; grade 4: blastomeres of unequal size, >50% cytoplasmic fragments and granular blastomeres. Besides the scoring of embryo quality, participants were asked which of the five assessed embryos they would have selected for transfer. The coefficient of variation (CV) for average cell number and gradation was calculated per laboratory and per embryo video fragment (all participants). Results: Interobserver variability in terms of mean CV of cell number is 11.5 ± 1.35%. There is more variability when low cell numbers are scored (4-6 cells). The mean CV for embryo grade is 23.49 ± 1.30% The scoring of better quality embryos (grade 1 or 2) was related to a higher CV in the grading of the embryo in between different participants. The average agreement for the choice of the best embryo to transfer is about 70% with a range from 48 to 94%. Conclusions: There is a substantial inter-observer variability (CV 25-40%) when grade 1 or 2 embryos are scored by different participants. This variability could alter the selection of embryos for transfer in between different participants as shown in the 70% percentage of agreement for the embryo selected for transfer. A web-based external quality control survey enables IVF professionals to evaluate their performance in order to increase the percentage of agreement in selection of the best embryo for transfer.
    Full-text · Article · Jan 2012 · Human Reproduction
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    ABSTRACT: This study was designed to determine if the efficiency of in-vitro maturation (IVM) in women with normal ovaries can be improved by gonadotrophin administration. 400 women were randomly allocated in four groups: group A, non-primed cycles; group B, human chorionic gonadotrophin (HCG)-primed cycles; group C, FSH-primed cycles; and group D, FSH- plus HCG-primed cycles. There were significant differences in the IVM rate among the groups. In groups where HCG was used, the overall maturation rate was higher (57.9% in group B and 77.4% in group D; 48.4% in group A and 50.8% in group C) and the percentage of total available metaphase II-stage oocytes was higher (60.4% in group B and 82.1% in group D; 48.4% in group A and 50.8% in group C). The overall clinical pregnancy rate per transfer (CPR) was 18.3% and the implantation rate (IR) was 10.6%. There was a difference in CPR among the groups: group D (29.9%) versus group A (15.3%), P = 0.023; group D versus group B (7.6%), P < 0.0001; group D versus group C (17.3%), P = 0.046. The results of this study are clearly in favour of FSH plus HCG priming. FSH priming and HCG priming alone showed no significant effects on clinical outcome.
    No preview · Article · Sep 2009 · Reproductive biomedicine online
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    ABSTRACT: The in-vitro maturation protocol (IVM) is an intriguing tool in assisted reproduction since it omits the side-effects of drug stimulation and reduces the cost of the entire procedure, both in terms of time and patient/society costs. In the Biogenesi Reproductive Medicine Centre, the IVM technique has been applied for more than 3 years, obtaining successful results in terms of maturation and fertilization rates, number of pregnancies and healthy babies born. At present, IVM is widely accepted in polycystic ovary and polycystic ovarian syndrome patients but its application in other women is still controversial. This study has been carried out in order to determine the efficiency of unstimulated IVM in women with morphologically and endocrinologically normal ovaries. Body mass index, basal FSH and oestradiol concentrations, antral follicle count, endometrial thickness and lead follicle size were correlated with the outcome of the procedure so as to obtain useful criteria to select women with regular cycles for an IVM technique. It was found that basal oestradiol concentration, FSH concentration and antral follicle count are useful criteria in deciding whether to start and continue the procedure, while lead follicle size and endometrial thickness are important criteria in deciding the timing of oocyte retrieval.
    No preview · Article · Mar 2009 · Reproductive biomedicine online

Publication Stats

110 Citations
14.04 Total Impact Points