816 research outputs found

    O-225. Early cleavage of in-vitro fertilized human embryos to the 2-cell stage: a novel indicator of embryo quality and viability

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    A number of non-invasive methods have been proposed to evaluate embryo viability in human in-vitro fertilization programmes. In addition to biochemical analyses, a common method for the selection of embryos prior to transfer involves assessment of embryo quality and morphology. We propose a new method to evaluate embryo viability based on the timing of the first cell division. Fertilized embryos that had cleaved to the 2-cell stage 25 h post-insemination were designated as 'early cleavage' embryos while the others that had not yet reached the 2-cell stage were designated as 'no early cleavage'. In all cases the early cleavage embryos were transferred when available. Early cleavage was observed in 27 (18.9%) of the 143 cycles assessed. There were significantly (chi2 = 4.0; P = 0.04) more clinical pregnancies in the early cleavage group, 9/27 (33.3%), compared with the no early cleavage group, 17/116 (14.7%). No difference was found when comparing key parameters (age, stimulation protocol and semen characteristics) of couples belonging to both groups, pointing to an intrinsic property or factor(s) within the early cleaving embryos. We propose 'early cleavage' as a simple and effective non-invasive method for selection and evaluation of embryos prior to transfe

    Fertilization and early embryology: Evidence of sperm entry into assumed unfertilized human oocytes after sub-zonal sperm microinjection

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    Sub-zonal sperm microinjection (SUZI) as a treatment for male factor infertility can facilitate fertilization, however, in many cases oocytes remain unfertilized even though the sperm is placed in close contact with the oolemma. In order to improve our understanding of gamete interaction in cases of failed fertilization, we have analysed the failed fertilized oocytes from both SUZI and conventional in-vitro fertilization. The fluorochrome Hoechst 33342 (which binds specifically to DNA) was used to check for the possible presence of paternal chromatin in the unfertilized oocytes. A significantly higher (P < 0.01) number of microinjected oocytes showed signs of fertilization 2-3 days after sperm microinjection compared to normally inseminated oocytes, 30/175 (17.1%) and 2/79 (2.5%) respectively. In addition, four out of eight couples returning for a second treatment by SUZI displayed anomalies in fertilization in both cycles. The semen characteristics of patients with or without anomalies in fertilization was not different. The irregularities observed in the fertilization process infer that certain male factor patients have intrinsic sperm anomalies lying at the sperm membrane and/or chromatin level that could lead to anomalies in the appearance of the pronucle

    IVF treatment of moderate male factor infertility: a comparison of mini-Percoll, partial zona dissection and sub-zonal sperm insertion techniques

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    In this study we examined various techniques of in-vitro fertilization (IVF) for treating couples in whom the male had subnormal semen parameters. We compared two sperm preparation methods (mini-Percoll and conventional swim-up) for efficiency of recovery after preparation and for fertilization rates after IVF, and compared the suitability of partial zona dissection (PZD) and sub-zonal sperm insertion (SUZI) to patients with different types of male factor infertility. The mini-Percoll technique allowed the recovery of significantly more motile spermatozoa from the same semen sample compared to the swim-up method. More oocytes were fertilized after spermatozoa were prepared by the mini-Percoll technique. An increased number of spermatozoa recovered from an ejaculate led to an improvement in the quality of spermatozoa in the insemination droplet. Subsequently, when using the PZD technique, the fertilization rate increased when there was a higher number of spermatozoa in the patient's ejaculate. When comparing the two micromanipulation techniques, SUZI provided patients with oligoasthenzoo-spermia (i.e. < 10 × 106 spermatozoa/ml and 40% motility) with a higher chance of obtaining 2-pronculeate egg

    Sperm nuclear DNA damage and altered chromatin structure: effect on fertilization and embryo development

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    In the first part of this report we investigate whether chromatin anomalies in human spermatozoa can influence fertilization after intracytoplasmic sperm injection (ICSI). We have examined the sperm chromatin packaging quality using the chromomycin A3 (CMA3) fluorochrome and the presence of DNA damage in spermatozoa using in-situ nick translation. When comparing the spermatozoa of patients undergoing in-vitro fertilization (IVF) and ICSI distinct differences are evident in that ICSI males have a higher CMA3 fluorescence, indicating spermatozoa with loosely packed chromatin, and more spermatozoa containing endogenous DNA nicks. When examining the unfertilized oocytes of ICSI patients we found that men who had a high percentage of anomalies in their chromatin, i.e. >30% CMA3 fluorescence and >10% nicks, had more than double the number of unfertilized oocytes containing spermatozoa that had remained condensed. The observation that failed fertilized oocytes, injected with spermatozoa from patients with a higher percentage of sperm nuclear anomalies, contain more condensed spermatozoa indicates that a selection process against these spermatozoa may be in place at the time of fertilization. In the second part of the study we show that spare ICSI embryos have significantly lower rates of development to the blastocyst stage compared with those developed after routine IVF. These results show that a greater understanding of the molecular basis of male infertility is therefore needed to broaden our knowledge on the effect that abnormal spermatozoa have on fertilization and embryo developmen

    Sperm chromatin anomalies can influence decondensation after intracytoplasmic sperm injection

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    In this study we investigated whether morphology and chromatin anomalies in human spermatozoa can influence fertilization after intracytoplasmic sperm injection (ICSI). We examined unfertilized oocytes, using the fluorochrome Hoechst 33342, to determine whether a relationship exists between failure of fertilization and sperm chromatin quality. Sperm chromatin packaging quality was assessed using the chromomydn A3 (CMA3) fluorochrome, and the presence of DNA damage in spermatozoa, using in-situ nick translation. Normal males present sperm parameters with a normal morphology of >20%, CMA3 fluorescence of <30% and exhibit endogenous nicks in <10% of their spermatozoa. When patients were separated according to these values no difference was observed in their fertilization rates after ICSL When the unfertilized ICSI oocytes were examined, we found that patients with CMA3 fluorescence of <30% and nicks in <10% of their spermatozoa had only 17.5 and 21.6% respectively of their unfertilized oocytes containing spermatozoa that remained condensed. In contrast, patients with higher CMA3 and nick values had a significantly higher number, 412 and 48.9%, of their unfertilized oocytes containing condensed spermatozoa. Sperm morphology did not show any such pattern. The percentage of spermatozoa which had initiated decondensation in unfertilized oocytes was not influenced by morphology, CMA3 fluorescence or nicks. In light of these results we postulate that poor chromatin packaging and/or damaged DNA may contribute to failure of sperm decondensation after ICSI and result in failure of fertilizatio

    Effects of reducing growth rate via diet dilution on bone mineralization, performance and carcass yield of coccidia-infected broilers

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    Coccidiosis and rapid growth rate (GR) compromise bone mineralization in modern broilers. We tested the hypothesis that reducing GR via diet dilution during peak bone development will improve bone mineralization in both infected and uninfected broilers. A total of 384 male Ross 308 chicks were allocated to a basal grower diet (3,107kcal/kg ME and 19.4% CP) diluted with 0, 5, 10, or 15% lignocellulose (n = 12 pens/treatment, 8 birds/pen) at day 10 of age. Prior to this, birds in each group received half the intended diet-dilution levels (day 8 to 10 of age) and a common starter diet (day 1 to 7 of age). At day 13 of age (day 0 post-infection, pi), birds were orally inoculated with either 7,000 sporulated Eimeria maxima oocysts (I) or water (C), forming a 4 diet-dilution level × 2 infection status factorial experiment. Performance was measured over 12 days pi and scaled to BW at infection (day 0 pi) to account for a priori BW differences. At day 12 pi (day 25 of age), 1 bird/pen (a total of 6 birds/treatment) was sampled to assess tibia and femur mineralization relative to BW, and carcass yield. There was no interaction (P > 0.05) between infection status and diet-dilution level on ADFI/BW measured over day 1 to 12 pi, or on any bone variable. ADG/BW pi decreased (P 0.05) amongst I birds. I compared to C birds had reduced breast meat (P < 0.05) and eviscerated carcass yield (P < 0.01), femur (P < 0.05) and tibia (P < 0.01) breaking strength (BS), and femur ash weight (AW) (P < 0.05). Diet dilution did not affect carcass yield, but improved femur BS (P < 0.001), and tended to improve (P < 0.1) femur and tibia AW. Overall, diet dilution significantly affected femur, more than tibia, variables: relative BS, robusticity index, and ash percentage. Reducing GR affected broiler long bone mineralization to a similar degree in the presence or absence of coccidiosis

    Fertilization and early embryology: Use of lasers in assisted fertilization and hatching

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    The erbium-yttrium-aluminium-garnet (Er: YAG) laser has been applied to micromanipulation in humans. It was used in the fertilization process for both subzonal insemination (SUZI) and for partial zona dissection (PZD). Laser-assisted micromanipulation achieved significantly higher fertilization rates (34.8%) when compared to mechanical SUZI (16.1%), but use of the laser did not improve the PZD results (laser 14.8% versus mechanical 14%). The Er: YAG laser was used to assist hatching. In the mouse it significantly improved the hatching rate (80 versus 29.3%) 110 h after administration of human chorionic gonadotrophin. This technique was applied in two different centres to patients with previous in-vitro fertilization (IVF) failures. The implantation rate per embryo (14.4% laser-assisted hatching versus 6% control group) and the pregnancy rate per transfer (40 versus 16.2%) were improve
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