ORCID Profile
0000-0002-4436-5162
Current Organisation
University of Valencia
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Publisher: Wiley
Date: 11-1993
Abstract: The present study was carried out to test whether the zona pellucida selects spermatozoa with higher fertilization potential. Fertilization rates of mouse oocytes after sperm microinjection under the zona pellucida (SMUZ) of zona-bound spermatozoa and of spermatozoa incubated in the absence of oocytes and treated (acid-treated group) or not (control group) with acid Tyrode's solution were compared. SMUZ was performed at 15, 30, 60, and 90 min after the insemination of fresh oocytes required for selecting spermatozoa bound to the zona pellucida. At these times, the percentages of acrosome-reacted spermatozoa (PARS) were evaluated using the chlortetracycline fluorescence method. Fertilization rate in the three groups analysed increased from 25.9% to 47.3% in the control group, from 29.3% to 44.0% in the acid-treated group, and from 19.5% to 40.0% in the zona-bound group from 15 to 90 min after insemination, respectively. The global fertilization potential was significantly lower in the zona-bound group compared to the other two groups. The PARS in the zona-bound group at 15 (11.48 +/- 3.02), 30 (16.74 +/- 3.71), and 90 (19.68 +/- 3.68) min after insemination were significantly (P < 0.05) lower than those found in the acid-treated group (39.26 +/- 6.69, 38.20 +/- 6.24, and 42.83 +/- 5.39, respectively). At 90 min after insemination, the PARS in the zona-bound group was also significantly (P < 0.05) lower than the control group (36.72 +/- 4.51). No significant correlation between either time and PARS or PARS and fertilization rate was observed. It appears that the zona pellucida does not select from the medium spermatozoa with higher fertilization potential.
Publisher: Oxford University Press (OUP)
Date: 12-1993
DOI: 10.1095/BIOLREPROD49.6.1362
Abstract: This study was conducted to determine whether the tolerance of embryos to the stress of freezing and thawing can be modified by including in the incubation medium stimulators or inhibitors of membrane lipid peroxidation. Mouse zygotes were cultured in medium M16, supplemented or not with FeSO4, apotransferrin, and/or ascorbate. In each culture supplement, 8-cell embryos were randomly allocated to an untreated (nonfrozen) control group, or treatment by freezing using slow or ultra-rapid cooling. In the slow-frozen group, FeSO4 (49.3%, 66 of 134), decreased embryo survival, whereas apotransferrin (82.7%, 110 of 133) and ascorbate (86.4%, 114 of 132), increased significantly the percentage of intact embryos recovered after thawing compared to those cultured in the basic medium M16 (66.9%, 99 of 148). Apotransferrin and ascorbate also increased significantly the percentage of blastocysts on Day 5 (79.7%, 106 of 133, and 89.4%, 118 of 132 vs. 62.2%, 92 of 148, respectively). Ascorbate, in addition, increased significantly the percentage of implantations compared to those in the basic medium M16 (84.5%, 60 of 71 vs. 61.1%, 37 of 56). Changes in the ultra-rapidly frozen group were not so evident. However, a significant fetal wastage after implantation was observed when embryos were cultured without additives and then ultra-rapidly frozen (31.7%, 13 of 41 vs. 7.0%, 3 of 43, in the nonfrozen control group). Fetal weight was similar between culture conditions, but it was significantly lower in slow-frozen and ultra-rapidly frozen embryos than in the nonfrozen control group.(ABSTRACT TRUNCATED AT 250 WORDS)
Publisher: CSIRO Publishing
Date: 1994
DOI: 10.1071/RD9940033
Publisher: Wiley
Date: 05-1993
Abstract: In order to minimize the percentage of false-negative results in the zona-free sperm penetration assay (SPA), a wide range of substances and/or physical agents capable of inducing the acrosome reaction (AR) have been incorporated in the incubation medium. These agents can also be used for treatment of severe male infertility using the technique of sperm microinjection under the zona pellucida (SMUZ). In the present review, the percentages of acrosome-reacted spermatozoa induced by several physiological, biochemical or physical agents published in the literature are compared in order to find the most efficient method(s) of inducing the AR in human sperm as a previous requirement of optimizing the technique of SMUZ. A working estimate of the level of efficiency of a given AR inducer is calculated by adding up its range score in each of three different arrangements from the highest to the lowest value of percentages of AR and differences in percentages of AR and penetration indexes between treated and control groups in SPA. The agents able to induce the AR by nonphysiological (electropermeabilization, lysophosphatidyl choline, and freezing-thawing) have better positions in this hierarchical system than those ones which require the active participation of sperm membrane receptors or second messenger systems (progesterone, zona pellucida, and stimulators of protein kinase A). Electropermeabilization appears to be the most efficient AR inducer. However, more possibilities need to be explored to enhance the relatively low percentages of acrosome-reacted spermatozoa shown by infertile men.
Publisher: Oxford University Press (OUP)
Date: 09-1999
Abstract: In a recent CD-ROM, we portrayed the microstructure of the pre-implantation human embryo (Sathananthan et al., 1999), which was a multimedia production with computer colour-enhanced electron micrographs of mainly monospermic embryos. This disk portrays light and electron micrographs of over 250 tripronuclear (3PN), dispermic, human embryos during pre-implantation development, viewed in thick and thin Araldite sections, as well as appearances of whole embryos flat embedded in Araldite blocks visualized with the light microscope. The 100 figures were computerized (IBM TIFF format), edited and labelled using Adobe Photoshop 5. Some of the figures were coloured on computer. The early development of 3PN embryos overtly resembles that of normal embryos but there are important differences in their microstructure which are portrayed in this presentation. This is a multicentric study involving researchers from four IVF centres.
No related grants have been discovered for Juan Tarín.