Trapeziometacarpal joint loading during key pinch grip: A cadaver study

To our knowledge, no study has directly measured the loads in the trapeziometacarpal joint during an isometric key pinch. The aim of this study was to measure the load acting on the trapeziometacarpal joint for increasingly greater key pinch forces (0.5 kg-1.5 kg). We performed a cadaver study using 10 fresh-frozen, unembalmed adult forearms and hands (5 right and 5 left). Thumb pinch was simulated by loading the main actuator tendons involved in the key pinch grip (i.e., adductor pollicis, flexor pollicis longus, extensor pollicis longus, extensor pollicis brevis and abductor pollicis longus tendons). Measurements were made inside the joint using a force-sensing resistor sensor (Tekscan® FlexiForce™ force sensor). All specimens were tested twice in a row in the same condition. The median load values recorded in the trapeziometacarpal joint were 1.9 kg (IQR 2.2-1.5), 3 kg (IQR 3.4-2.7) and 4.1 kg (IQR 4.4-3.9) during 0.5 kg, 1 kg, and 1.5 kg key pinch, respectively. For each specimen, similar load values were observed during both loading trials. Our findings indicate that the loads measured directly in the trapeziometacarpal joint during a simple key pinch are materially lower than those estimated in biomechanical models of the thumb (generally greater than 10 kg for 1 kg of applied force) probably due to intersubject variability. This pilot study will serve as a basis for further studies, for example, comparing biomechanical thumb models and experimental measurements under the same set-up conditions.

Assessment of trapezial prosthetic cup migration: A biomechanical study

We performed a biomechanical study using 60 Sawbones® rigid foam blocks of two simulated densities (osteoporotic, n = 30 and non-osteoporotic, n = 30) and 10 cadaveric trapezium bones from fresh-frozen, unembalmed adult cadaver hands to assess the trapezial prosthetic cup migration with progressively greater compression loads (10-40 kg). Two cups from the Touch® prosthesis were compared: 9-mm conical cup and 9-mm spherical cup. Uniaxial compression tests were carried out using an MTS Criterion® Series 40 Electromechanical Testing System. Cup migration was measured in millimeters (mm) at 10, 20, and 40 kg of compression load. Median cup migration values were similar in the cadaveric trapezium bones and Sawbones® non-osteoporotic blocks, and higher in the Sawbones® osteoporotic blocks. In the cadaveric trapezium bones and the Sawbones® non-osteoporotic blocks, migration values were less than or equal to 0.1 mm for 10 and 20 kg loads; it was 0.2 mm for 40 kg load. In the Sawbones® osteoporotic blocks, migration values were less than or equal to 0.3 mm for 10 and 20 kg loads; it was 0.4-0.5 mm for 40 kg load. There was no significant difference between the two cup shapes in both cadaveric trapezium bones and Sawbones® non-osteoporotic blocks. In Sawbones® osteoporotic blocks, the largest difference between the two cup shapes was 0.1 mm for loads up to 40 kg, which corresponded to our measurement accuracy. Our findings indicate that the trapezial component of total trapeziometacarpal joint arthroplasty undergoes very weak migration for axial compression loads up to 40 kg, presumably below the threshold of clinical relevance. The cup shape did not have an obvious influence; however, low bone mineral density may result in greater cup migration.

O-182 Higher risk of preeclampsia and pregnancy-induced hypertension with artificial cycle for Frozen-thawed Embryo Transfer compared to ovulatory cycle or fresh transfer following In Vitro Fertilization

Study question

Is there an increased risk of preeclampsia after Frozen-thawed Embryo Transfer(FET) compared to In Vitro Fertilization-fresh transfer(IVF-fresh-ET) according to endometrial type of preparation for FET?

Summary answer

The frequency of preeclampsia and hypertension were significantly higher in the group of artificial cycle (AC-FET) compared to ovulatory cycle (OC-FET) and fresh-ET (P < 0.0001).

What is known already

Risks of maternal morbidity are known to be reduced in pregnancies resulting from FET compared to fresh-ET except for the risk of preeclampsia, that was reported to be significantly higher in pregnancies resulting from FET compared to fresh-ET or spontaneous conception. Most recent studies demonstrate an equal live birth rate with either OC-FET or AC-FET preparation. Few studies compared the maternal vascular morbidities with the two hormonal environments that preside over the early stages of embryonic development: OC (major role of the corpus luteum) and AC (prolonged hormone replacement with high doses of estrogen and progesterone).

Study design, size, duration

We conducted a 2013-2018 French nationwide cohort study comparing maternal vascular morbidities in 3 groups of single pregnancies> 22 weeks of gestation (WG): FET with AC or OC preparation, and IVF (conventional or ICSI)-fresh-ET.Data were extracted from the French National Health System database (>99% of national deliveries) in which all hospitalizations are registered, containing information on patient characteristics, diagnoses and treatments. Records were merged anonymously. Access to the database was legally approved.

Participants/materials, setting, methods

68 025 deliveries were included: fresh-ET(n = 48 152), OC-FET(n = 9 500), AC-FET(n = 10 373). In OC-FET, a luteal phase support with progesterone was administered for maximum 6 WG if pregnancy. In AC-FET, progesterone was co-administered with estrogen until 12 WG. Embryos were transferred at cleavage or blastocyst stage.

Vascular disorders were recorded if hospitalization for preeclampsia/eclampsia or hypertension (history of hypertension excluded). Maternal characteristics were included in multivariate analysis. Adjusted odds ratios(aOR) and 95% confidence intervals(CI) were estimated.

Main results and the role of chance

Maternal characteristics: In multivariate analysis, patients in the FET groups were older (33.4 years (std=4.3) vs. 33.2 years (std=4.4) for fresh-ET, respectively, P < 0.0001), less often primiparous (aOR=0.68[0.66-0.71], P < 0.0001) or smokers (aOR=0.84[0.75-0.95]) or with premature ovarian insufficiency (POI) (aOR=0.68 [0.58-0.79]), more frequently with polycystic ovaries (PCOS) (aOR=1.25[1.12-1.39]) and comparable for obesity or diabetes.

In FET groups, 52.2% were AC-FET. There was no difference for maternal age, parity, obesity, smoking, history of diabetes between AC and OC-FET. Endometriosis (aOR=1.26[1.16-1.38]), PCOS (aOR=1.79[1.50-2.15]) and POI (aOR=2.0[1.48-2.72]) were more frequent in AC-FET.

Risks of vascular disorders

The rate of preeclampsia (5.3% vs. 2.3% vs. 2.4%, respectively, P < 0.0001) and hypertension (4.7% vs. 3.4% vs. 3.3%, respectively, P = 0.0002) was significantly higher in AC-FET versus OC-FET and fresh-ET.

In multivariate analysis, the risk of preeclampsia increased with age, primiparity, obesity, diabetes and POI. The risk was higher in AC-FET versus OC-FET (aOR=2.42 [2.06-2.85]) and fresh-ET (aOR=2.43[2.2-2.7]), P < 0.00001. No difference was found between OC-FET and fresh-ET (P = 0.91). The risk of pregnancy-induced hypertension increased with age >40, primiparity, smoking, obesity and diabetes and was higher in AC-FET versus OC-FET (aOR=1.50[1.29-1.74], P < 0.0001) and fresh-ET (aOR=1.50[1.35-1.67], P < 0.0001) and not different between OC-FET and fresh-ET (P = 0.86).

Limitations, reasons for caution

While the strength of this study relies in the number and exhaustiveness of subjects analysed, its limitations are its retrospective and register-based nature that did not enable to refine the risk according to details of techniques and treatments in each group.

Wider implications of the findings

This large nationwide cohort study highlights 2 important information for physicians : i) the possible deleterious role of high supra-physiological and prolonged doses of estrogen-progesterone supplementation on vascular pathologies ii) the protective role of the corpus luteum present in stimulated or spontaneous OC for their prevention.

Trial registration number

Not applicable

Efficacy of assisted reproductive technology after ovarian tissue transplantation in a cohort of 11 patients with or without associated infertility factors

PURPOSE

IVF treatment in women with grafted frozen-thawed ovarian tissue is associated with poor reproductive outcomes. The aim of this study was to evaluate the efficacy of ovarian tissue transplantation (OTT) followed by assisted reproductive technology (ART) in women with or without associated infertility factors.

METHODS

This is a prospective cohort study with retrospective data collection including eleven women, four of whom having an infertility factor (IF), who had undergone OTT in one university center between 2005 and 2017, followed by ART in six in vitro fertilization (IVF) centers.

RESULTS

In total, 25 of the 85 cycles initiated (29%) were canceled, resulting in 60 oocyte retrievals. Ninety-five oocytes were retrieved: 36 were abnormal or immature, 29/39 fertilized (74%) after ICSI and 13/20 (65%) after IVF. Thirty-five embryos were transferred in seven patients (5/7 patients without IF and 2/4 patients with IF). After ART, one patient with IF experienced two pregnancies, one resulting in a live birth. For all patients, pregnancy rates and live birth rates were 7.4% and 3.7% per embryo transfer, respectively. Nine pregnancies and four live births occurred after spontaneous conception in five patients without IF, none in the infertility group.

CONCLUSION

This study confirms that IVF treatment in women with grafted frozen-thawed ovarian tissue is associated with poor outcomes. However, the chances of natural conception are high in women without IF. Patients with IF, without the possibility of spontaneous pregnancy, should be informed of poor reproductive outcomes after OTT followed by ART.

TRIAL REGISTRATION NUMBER

NCT02184806.

Abstract 2871: The Nanoprimer: a nanoparticle designed to transiently occupy the mononuclear phagocytic system in order to increase nanomedicine-based treatments efficacy

Introduction: Most nanomedicines are currently limited in their efficacy due to a sub-optimal biodistribution/accumulation in the target tissues. A large part of the administered dose remains useless due to the high rate of clearance by the mononuclear phagocytic system (mainly by Kupffer cells in liver). We designed a new approach based on the use of an engineered, biocompatible nanoparticle–the Nanoprimer–that is administered before the nanomedicine in order to transiently and specifically occupy the liver clearance pathways responsible for sub-optimal therapeutic bioavailability. The Nanoprimer's effect is only based on its specific physico-chemical properties, there is no active principal ingredient encapsulated in it. Here we demonstrate the ability of the Nanoprimer to redefine the bioavailability and efficacy of nanomedicines loaded with small molecules or nucleic acid. We evaluated the biodistribution and the safety of the Nanoprimer alone and of an irinotecan loaded liposome combined with the Nanoprimer.

Methods: Quantitative evaluation of the Nanoprimer's biodistribution was performed by mass spectrometry. Safety profile of the Nanoprimer was evaluated in vitro (cell viability, cytokines/interleukins expression profile, complement activation, phagoburst and phagotest on different cell lines) and in vivo, in mice, by a follow up of body weight and clinical signs, histological observations of liver, spleen and lungs and blood parameters titration, after the injection of a maximized dose of Nanoprimer. The impact of the Nanoprimer on the bioavailability and biodistribution of nanomedicines loaded with irinotecan or nucleic acids (mRNA / SiRNA) was evaluated by HPLC and fluorescence quantification, respectively. Finally, the impact of the Nanoprimer on treatment was evaluated using nanomedicines encapsulating human erythropoietin (hEPO) mRNA, Factor VII (FVII) siRNA or irinotecan.

Results: The Nanoprimer presents a rapid accumulation within liver and spleen. The Nanoprimer was well tolerated with no sign of toxicity observed using therapeutic dosage. The administration of the Nanoprimer increases systemic bioavailability of different type of nanomedicines and enhances their accumulation in target tissues. This improved bioavailability is correlated with an increased secretion of hEPO by 30%, for mRNA-loaded nanomedicines, an increased silencing of FVII by 50%, for siRNA-loaded nanomedicines, and an increased anti-tumor efficacy by 50%, for irinotecan-loaded nanomedicines.

Here, we showed the safe profile of the Nanoprimer and its ability to increase the treatment outcomes for different nature of nanomedicines. The separation of the functions ensuring the efficacy of a treatment into two distinct objects opens perspectives for designing future nanomedicines and a shift in the therapeutic paradigm.

Citation Format: Julie Devalliere, Laurence Poul, Audrey Darmon, Oceane Jibault, Maxime Bergere, Francis Mpambani, Nell Saunders, Marion Paolini, Robert Langer, Matthieu Germain. The Nanoprimer: a nanoparticle designed to transiently occupy the mononuclear phagocytic system in order to increase nanomedicine-based treatments efficacy [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2871.

To be or not to be [fertile], that is the question

Background

According to our literature analysis, there are no data focused on spermatozoa emotional representations in childless men and data on the emotional repercussions of a diagnosis of infertility on men are still scarce. Thus, in this work, we investigated what the presence or absence of spermatozoa in the semen symbolize for men.

Material and methods

To answer this question, 441 childless heterosexual men participated in an anonymous, prospective, Internet-based survey.

Results

In response to the question “What would having a high or normal sperm count symbolize for you?” the most frequent answer was “ability to father a child”. Men living with a partner were significantly more likely than single men to answer “ability to father a child” (p < 0.05) and less likely to answer “virility” and/or “ability to have an erection/ejaculation” (p = 0.001). In response to the question “If you found out that you had a low sperm count or no spermatozoa at all, how would you feel?”, most of the men stated that they would be disappointed. Men living with a partner were more likely to state that they would feel ashamed (p < 0.05) or guilty with regard to their partner (p < 0.0001).

Conclusions

These preliminary results should help us to improve (i) the way that male infertility is announced (it is easier to find the right words if one understands the possible importance of having a high sperm count) and (ii) the psychological, marital and sexual counselling provided to men with a diagnosis of infertility.

High-magnification selection of spermatozoa prior to oocyte injection: confirmed and potential indications

Intracytoplasmic morphologically selected sperm injection (IMSI) involves the use of differential interference contrast microscopy at high magnification (at least ·6300) to improve the observation of live human spermatozoa (particularly by showing sperm head vacuoles that are not necessarily seen at lower magnifications) prior to intracytoplasmic sperm injection (ICSI) into the oocyte. However, a decade after IMSI’s introduction, the technique’s indications and ability to increase pregnancy and/or birth rates (relative to conventional ICSI) are subject to debate. In an attempt to clarify this debate, this work performed a systematic literature review according to the PRISMA guidelines. The PubMed database was searched from 2001 onwards with the terms ‘IMSI’, ‘MSOME’ and ‘high-magnification, sperm’. Out of 168 search results, 22 relevant studies reporting IMSI outcomes in terms of blastocyst, pregnancy, delivery and/or birth rates were selected and reviewed. The studies’ methodologies and results are described and discussed herein. In view of the scarcity of head-to-head IMSI versus ICSI studies, the only confirmed indication for IMSI is recurrent implantation failure following ICSI. All other potential indications of IMSI require further investigation.

Tumor necrosis factor-308 polymorphism increases the embryo implantation rate in women undergoing in vitro fertilization

STUDY QUESTION

Do TNF-308 and -238 polymorphisms impact the embryo implantation rate after in vitro fertilization (IVF) in women without female infertility factor?

SUMMARY ANSWER

The presence of the TNF-308A allele is associated with high implantation and multiple pregnancy rates in women without known infertility factors after ovarian hyperstimulation with exogenous FSH.

WHAT IS ALREADY KNOWN

Multiple pregnancies are frequent after the use of Assisted Reproductive Technologies. Single embryo transfer (SET) has been proposed as a simple way to prevent these risks. However, the extension of SET indications to patients not selected based on specific criteria is controversial because of reduced pregnancy rates. To date, the predictive value of the parameters used for SET (age, gynecological history of the patient and uterine characteristics) allows a pregnancy rate of ~30%.

STUDY DESIGN, SIZE, DURATION

The potential predictive value of TNF polymorphisms (-308, rs1800629 and -238, rs361525) on implantation rate was evaluated in 424 women requiring IVF due to male fertility factors. This cohort retrospective study was conducted over 4 years in University-affiliated hospitals.

PARTICIPANTS, SETTING, METHODS

The entire patient group included 424 women undergoing intracytoplasmic sperm injection (ICSI) due to male fertility factors without the contribution of any female factor. From among this group, a selected patient group included 120 women with a normal karyotype, age under 38 years, serum follicle-stimulating hormone (Day-3 FSH) levels below 10 IU/l, a long agonist desensitization protocol associated with recombinant FSH treatment and a Caucasian background.

MAIN RESULTS AND THE ROLE OF CHANCE

The TNF-238 polymorphism was not associated with implantation rate. In contrast, the presence of the TNF-308A allele was associated with increased Day 3-E2 levels as well as higher implantation and multiple pregnancy rates after fresh embryo transfer in women from the entire and selected patient groups. Moreover, in the selected patient group, the presence of the TNF-308A allele was also associated with a decrease in the miscarriage rate. The benefit of the TNF-308A allele in predicting implantation rates was not observed after the use of frozen embryos.

LIMITATIONS, REASONS FOR CAUTION

Future studies are needed to evaluate whether the TNF-308A allele might also be a biomarker in women with infertility factors.

WIDER IMPLICATIONS OF THE FINDING

The TNF-308A allele may represent a good candidate for a potential predictive, non-invasive biomarker in the SET strategy. However, its impact should be evaluated in prospective studies.

STUDY FUNDING/COMPETING INTEREST

This study was conducted with financial support from the French Institute for Health and Medical Research (INSERM), Organon France for a FARO (Fond d'Aide à la Recherche Organon) fellowship (to V.T.) and CHU Nice PHRC (PHRC 09-279).There are no competing interests.

Gamete cytogenetic study in couples with implantation failure: aneuploidy rate is increased in both couple members

PURPOSE

Implantation failure is known to be associated with an increased risk of aneuploidy in embryos, a situation leading to a pre-implantation genetic screening, not allowed in different countries like France. Our aim was to evaluate the gamete aneuploidy incidence in this context, using first polar body and spermatozoa aneuploidy screening.

METHODS

Three groups were considered: 11 couples with pregnancy obtained after IVF for female infertility (group 1); 20 couples with pregnancy obtained after IVF for male infertility (group 2); and 35 couples with implantation failure (group 3). In group 3, 28 couples treated by ICSI volunteered for first polar body analysis (PB1).

RESULTS

Spermatozoa aneuploidy rate was increased in groups 2 (1.6%) and 3 (2.1%) in comparison to group 1 (0.6%). PB1 aneuploidy rate was 35.4% in group 3. Finally, eight couples (32%) had no particular chromosomal risk in gametes, 15/25 (60%) presented an increased spermatic (>2%) or oocyte (>1/3) aneuploidy rate, and 2/25 (8%) had both.

CONCLUSION

Those results confirm that implantation failure has a heterogeneous origin, that gamete chromosome abnormality rate is one of the major contributing factors, and that 1st Polar body and spermatozoa aneuploidy screening or pre-implantation genetics screening may be indicated for these couples.

Oocyte aneuploidy mechanisms are different in two situations of increased chromosomal risk: older patients and patients with recurrent implantation failure after in vitro fertilization

OBJECTIVE

To clarify the mechanisms underlying oocyte abnormalities in meiosis: meiotic nondisjunction of a whole chromosome or premature separation of sister chromatids in two situations of increased chromosomal risk.

DESIGN

Preconception diagnosis by first polar-body analysis in two situations of increased chromosomal risk.

SETTING

Departments of reproductive biology, cytogenetics, gynecology, and obstetrics.

PATIENT(S)

First polar body analysis was proposed to 76 patients (91 cycles) for advanced age (AMA; n = 30, 36 cycles), recurrent implantation failure (RIF; >10 embryos transferred without implantation; n = 32, 36 cycles), or both (AMA + RIF; n = 14, 19 cycles), before their intracytoplasmic sperm injection procedure.

INTERVENTION(S)

First polar-body analysis using fluorescence in situ hybridization.

MAIN OUTCOME MEASURE(S)

Mechanisms and frequency of aneuploidy.

RESULT(S)

Three hundred eighty-four oocytes were analyzed by fluorescence in situ hybridization, 130 from women >38 years of age, 171 from women with RIF, and 83 from women with both indications. The oocyte abnormality rate was similar in the three groups, respectively, 38.5%, 40.4%, and 45.8%. The aneuploidy mechanisms were different for women >38 years of age who had no previous implantation failure (AMA) compared with women of whatever age who had implantation failure (P<.05 vs. RIF; P<.001 vs. AMA+RIF), with, respectively, for the AMA, RIF, and AMA+RIF groups, 72.2%, 56.6%, and 49.2% premature separation of sister chromatids and 27.8%, 43.4%, and 50.8% meiotic nondisjunction. In the two implantation-failure groups, we distinguished a subgroup (22% in the RIF group and 33% in AMA+RIF group) of patients with >2/3 abnormal oocytes, suggesting a meiosis alteration.

CONCLUSION(S)

The mechanisms accounting for oocyte aneuploidy differed in the two clinical situations of advanced maternal age and RIF. Advanced maternal-age aneuploidy was linked to a loss of sister chromatid cohesion that led to one single chromatid abnormality, whereas implantation failure is a much more heterogeneous situation.

Evidence of a high proportion of premature unbalanced separation of sister chromatids in the first polar bodies of women of advanced age

BACKGROUND

Maternal ageing is the only aetiological factor unequivocally linked to aneuploidy. Two mechanisms seem to explain these abnormalities in oocytes: non-disjunction and premature unbalanced separation of sister chromatids (PSSC). Previous studies of unfertilized oocytes argue for a major role of PSSC in the aetiology of aneuploidy for women of advanced age, but in vitro ageing of the oocytes could influence the results.

METHODS

Owing to the high prevalence of aneuploidy in women of advanced age, chromosomal screening of the first polar body just before ICSI was offered to women (from 38 years of age) included in an assisted reproduction programme.

RESULTS

Among 141 oocytes from 29 women (mean age 40 years and 2 months), 43 (30.5%) were abnormal. Sixty-five abnormalities were found and PSSC was involved in 80% of cases.

CONCLUSION

These results are in accordance with previous studies and confirm, in 'fresh' oocytes, the major role of PSSC in the aetiology of aneuploidy in women of advanced age.

Cryopreserved immature mouse oocytes: a chromosomal and spindle study

PURPOSE

Cryopreservation of human oocytes might provide an alternative approach to freezing supernumerary embryos obtained during IVF. This process, performed on immature denuded prophase 1 mouse oocytes, was investigated.

METHODS

We first investigated the capacity of frozen, immature, murine oocytes to continue in vitro maturation after thawing. We then evaluated the risk to offspring from chromosomal damage by cytogenetical and cytological (spindle) analysis. Finally, we attempted to determine the reasons for and the stage of maturation failure.

RESULTS

A total of 700 immature oocytes was frozen, 629 (90%) were recovered intact after thawing, and 53% extruded the first polar body, versus 74% for the control group. Freezing was not accompanied by an increase in aneuploidy in maturing oocytes (18 and 15% for thawed and control oocytes, respectively). Consequently, the first meiotic division occurred normally, without an increase in nondisjunction. Spindle analysis demonstrated only a few abnormalities (15 and 2% for thawed and control oocytes, respectively) incompatible with further development. Oocytes arrested during in vitro maturation were mainly at the metaphase I stage (64 and 76% for thawed and control oocytes, respectively). Whereas 17% of thawed oocytes were blocked before the formation of the first meiotic spindle, this never occurred in the control group.

CONCLUSIONS

Immature murine oocytes can withstand cryo-preservation, which is encouraging for future human application of this technique.

Chromosome 18 analysis by fluorescence in situ hybridization (FISH) in human blastomeres of abnormal embryos after in vitro fertilization (IVF) attempt

We performed fluorescence in situ hybridization (FISH) with a chromosome 18-specific probe on human abnormal cleaved embryos, fertilized either by two spermatozoa and exhibiting three pronuclei (3 PN) or normally fertilized and exhibiting two pronuclei (2 PN) with subsequent severe fragmentation and/or blocking. The aim of the study was to evaluate the incidence of chromosome 18 anomalies among these embryos in order to evaluate the FISH efficiency on such material and to obtain more precise and complete data than those obtained with classical cytogenetic analysis. For the 3 PN cleaved embryos, FISH confirmed the frequent regulation towards diploidy (25 per cent) and the high frequency of mosaics (53 per cent). For the 2 PN blocked or damaged embryos, FISH permitted chromosome evaluation, which was otherwise impossible with classical cytogenetic techniques: we also found a high mosaic frequency (45 per cent) with these embryos. If this frequency were the same for normally developing embryos, it would be a major obstacle to the reliability of either chromosomal or genetic preimplantation diagnosis.

[Assisted embryo hatching]

In spite of the progress in in vitro fertilization (IVF), implantation rate of IVF embryos remains low. Many factors seem to be involved in these results. Among them, impairment of the hatching process was incriminated by some authors. Assisted hatching seems to be an interesting method for repeated failures of IVF.

Influence of male sexual rest and oocyte aging on parthenogenesis frequency in mice: cytogenetic analysis after in vitro fertilization

This study was conducted to evaluate the influence of male sexual rest and oocyte aging on fertilization rate and parthenogenesis frequency after in vitro fertilization of mouse oocytes. We used a comparison between cleavage rates and fertilization rates according to chromosomal analysis of oocytes to estimate the parthenogenesis frequency. Fertilization rate was not impaired by male sexual rest. Parthenogenesis frequency was increased by male sexual rest. This effect was enhanced by a concomitant moderate oocyte aging. It is concluded that cleavage rate could not be considered as a reliable test of fertilization after attempted in vitro fertilization in such conditions.

Chromosome analysis of multipronuclear human oocytes after in vitro fertilization

Multipronuclear human eggs are frequent after in vitro fertilization. Their chromosome analysis can provide useful information. Before cleavage it can confirm the suspected polyploidy. Among the cleaved multipronuclear eggs it provides an estimation of the incidence of the possible return to diploidy. Ninety-four multipronuclear eggs were fixed at the first, second, or third cleavage according to the air-drying method of Tarkowski with or without colchicine exposure: 60 were successfully analysed. Twelve were stopped before cleavage (six without colchicine treatment and six with colchicine treatment). They were polyploid, confirming the cytological observation. Forty-eight eggs cleaved and were stopped by colchicine treatment and karyotyped. Seventeen eggs (35 per cent) had produced diploid embryos. Mosaicism was frequent (15 cases, 31 per cent). Triploidy was not frequent (8 eggs, 17 per cent). Haploidy constituted the remaining cases (8 eggs, 17 per cent). Our data indicate that the initial count of pronuclei is a reliable test. Multipronuclear one-cell oocytes were confirmed to be polyploid. Furthermore, the developmental capacity of the multipronuclear oocytes is variable. Most of them cleaved. However, many multipronuclear oocytes led to diploid cleaving eggs.