Showing papers by "Sergio Oehninger published in 2001"
TL;DR: It is concluded that cryopreservation-thawing of human sperm from patients and donors was associated with membrane change, as revealed by membrane translocation of phosphatidylserine, while having no major impact on DNA fragmentation.
Abstract: The objective of these studies was to evaluate the effect of cryopreservation-thawing of human spermatozoa on DNA fragmentation and membrane integrity. This was a prospective, controlled cohort study, performed at a university-based infertility center. Ejaculates were examined from 5 donors and 16 men undergoing infertility evaluation. Purified sperm populations were prepared by gradient centrifugation, cryopreserved using a manual method and TEST-yolk buffer and glycerol (TYB-G), followed by quick-thaw. Annexin V binding was used for assessing membrane translocation of phosphatidylserine, and terminal deoxynucleotidyl transferase-me-diated dUTP nick end labeling (TUNEL) was utilized for the evaluation of DNA fragmentation. The results were as follows: the percentage of live cells with intact membranes (annexin V−, live) was significantly reduced after cryopreservation-thawing. On the other hand, the percentages of live cells with phosphatidylserine translocation (annexin V+, live) and of necrotic (dead) cells increased significantly after thawing. TUNEL revealed percentages of cells with DNA fragmentation in the prefreeze and postthaw samples that were not significantly different. In a further attempt to examine differences in response to various cryoprotection protocols, experiments were carried out using no cryoprotection, glycerol alone, or TYB-G. Samples frozen with TYB-G demonstrated significantly higher percentages of live cells without phosphatidylserine translocation than the other conditions. We concluded that cryopreservation-thawing of human sperm from patients and donors was associated with membrane change, as revealed by membrane translocation of phosphatidylserine, while having no major impact on DNA fragmentation.
118 citations
TL;DR: Cryopreservation-thawing was associated with induction of membrane PS translocation; postthaw ROS levels were lower than before freezing; and neither annexin V binding results nor the generation of ROS were able to accurately predict sperm cryosurvival rates.
90 citations
TL;DR: It is shown that human oocytes through to blastocyst stage embryos express telomerase activity, but that the level of telomersase activity in biopsied blastomeres, of the day 3 cleavage stage embryo, is not predictive of embryonic growth potential.
Abstract: Telomerase, a ribonucleoprotein, has been described as an essential component of highly proliferative cells as it stabilizes the telomeres and avoids cellular senescence. The objective of this study was to modify the polymerase chain reaction-based telomeric repeat amplification protocol to detect telomerase activity in the single cell and to characterize the activity expressed in the human oocyte through to the blastocyst stage embryo. A comparative evaluation of telomerase activity and developmental stage was conducted using discarded or donated human oocytes and embryos. Telomerase activity was detected in all developmental stages evaluated from immature oocytes through to blastocyst stage embryos. Immature oocytes and blastocysts had similar levels of telomerase activity; however, both groups had significantly (P < 0.05) higher activity than zygote through to pre-morula stage embryos. Seventy-five thawed zygotes were cultured to day 3, biopsied by removing 1-2 cells, and the biopsied embryos were cultured to blastocyst stage. There was no difference (P < 0.05) in telomerase activity between cells biopsied from embryos that reached the blastocyst stage and cells from those that arrested in growth. This study has shown that human oocytes through to blastocyst stage embryos express telomerase activity, but that the level of telomerase activity in biopsied blastomeres, of the day 3 cleavage stage embryo, is not predictive of embryonic growth potential.
77 citations
TL;DR: Although patients had higher basal LPO than donors, LPO did not differ between fresh and cryopreserved-thawed fractionated motile spermatozoa and freezing-thawing was associated with translocation of PS to the external membrane leaflet.
Abstract: INTRODUCTION: This study investigated lipid peroxidation (LPO) and membrane integrity following cryopreservation-thawing. METHODS: Infertile men (study group) and donors (control group) were examined. Purified populations of highly motile spermatozoa were cryopreserved using TEST-yolk buffer and glycerol (TYB-G) followed by quick thaw. LPO was measured by a spectrophotometric assay, with and without a ferrous ion promoter. Annexin V binding was used to assess membrane translocation of phosphatidylserine (PS). RESULTS: Pre-freeze LPO was significantly higher in the study than in the control group (P = 0.03). In both groups, LPO measurements after thawing were significantly higher than the pre-freeze samples not exposed to TYB-G (P = 0.002 and P = 0.001 respectively). However, when the pre-freeze samples with TYB-G were compared with the post-thaw samples (all exposed to TYB-G), these differences were not significant. There was a significant increase in PS externalization following cryopreservation in both groups (P = 0.02 and P = 0.003 respectively). In donors, pre-freeze LPO concentrations had a significant positive correlation with thawed spermatozoa depicting PS externalization (r = 0.77, P = 0.04). CONCLUSION: Although patients had higher basal LPO than donors, LPO did not differ between fresh and cryopreserved-thawed fractionated motile spermatozoa. Freezing-thawing was associated with translocation of PS to the external membrane leaflet.
57 citations
TL;DR: A negative impact of a basal cycle high FSH:LH ratio (and possibly low LH levels) on follicular development and oocyte quality in these patients subjected to pituitary down-regulation followed by pure FSH administration is highlighted.
Abstract: Purpose: To examine the impact of low basal cycle day 3 serum LH levels or a high FSH:LH ratio on IVF results.
Methods: A homogeneous group of patients was analyzed as identified by normal basal cycle of follicle stimulating hormone (FSH), Luteinizing hormone (LH), and estradiol (E2) levels. High responders (high LH:FSH ratio) and low responders (high FSH or E2 levels, and women ≥42 years of age) were excluded from analysis. Only cycles stimulated with a combination of a GnRHa (luteal suppression) and pure FSH were studied.
Results: Patients with low basal LH levels (<3 mIU/mL) did not differ significantly from controls in terms of response to controlled ovarian hyperstimulation but there was a clear trend toward poorer implantation and clinical pregnancy rates. On the other hand, patients with a high FSH:LH ratio (<3) had significantly fewer mature oocytes aspirated, and lower implantation and clinical pregnancy rates than patients with gonadotropin ratio ≤3. These negative effects were evident in the presence of normal basal FSH levels and after adequate matching of female's age and number of embryos transferred.
Conclusions: These studies highlight a negative impact of a basal cycle high FSH:LH ratio (and possibly low LH levels) on follicular development and oocyte quality in these patients subjected to pituitary down-regulation followed by pure FSH administration. A high FSH:LH ratio may be therefore used as an early biomarker of poor ovarian response.
50 citations
TL;DR: Pregnancy rates are significantly decreased by initiating luteal-phase progesterone supplementation on day 6 after oocyte retrieval during in vitro fertilization cycles.
50 citations
TL;DR: The recombinant human zona pellucida protein 3 expressed in PA-1 cells manifested the full spectrum of expected biologic activities and represents a valuable tool for examination of human fertilization and the design of new strategies in diagnosis of male factor infertility and in contraception.
46 citations
TL;DR: It is concluded that the use of vaginal misoprostol may improve the chance for pregnancy in women having IUI in a wide variety of cycle types.
Abstract: This study examined whether the prostaglandin E(1) analogue misoprostol (400 microgram), when placed vaginally at the time of intrauterine insemination (IUI) improves pregnancy rates. A prospective, placebo-controlled, randomized and double-blind study involving 274 women in 494 IUI cycles resulted in a total of 64 pregnancies (13% per cycle). Misoprostol cycles totalled 253, with 43 pregnancies (17% per cycle), whereas placebo cycles totalled 241, with 21 pregnancies (9% per cycle). The cumulative pregnancy rate with misoprostol treatment was significantly greater than with placebo (P = 0.004, Cox proportional hazards regression). The benefit of misoprostol was seen in clomiphene cycles (14 versus 4%, P = 0.006), and was indicated in FSH cycles (33 versus 15%, borderline significance) and natural cycles (15.6 versus 7.7%, not significant), but was not seen in clomiphene/FSH cycles (18.2 versus 23.5%, not significant). Misoprostol treatment did not increase pain score on the day of IUI (1.1 versus 1.4) and at 1 day post IUI (0.6 versus 0.8). Complications were rare in both groups [six (2%) subject cycles in the misoprostol cycles compared with two (1%) in the placebo group]. It is concluded that the use of vaginal misoprostol may improve the chance for pregnancy in women having IUI in a wide variety of cycle types.
44 citations
TL;DR: The hypothesis that, in the human, sperm binding to the zona pellucida requires a ‘selectin-like’ interaction is proposed and results suggest a possible convergence in the types of carbohydrate sequences recognized during initial human gamete binding and immune/inflammatory cell interactions.
Abstract: The recognition of carbohydrate sequences by complimentary receptors has been shown to be a critical factor in gamete interaction in many different animal species. We have proposed the hypothesis that
42 citations
TL;DR: When combining testicular sperm extraction or microepididymal sperm aspiration with ICSI in patients with obstructive azoospermia, the results in terms of fertilization, implantation, and pregnancy rates were similar to those found in Patients with nonazoospermic obstruction who underwent ICSi with ejaculated sperm.
22 citations
TL;DR: The purpose of this prospective study was to assess the impact of different semen processing methods cryopreserved as whole semen and IUI-ready, and those washed for IUI after thawing on motility parameters postthaw.
Abstract: Different approaches have been implemented to improve the recovery and/or the quality of motile sperm after cryopreservation-thawing. Gradient separation of the motile fraction before freezing offers the possibility of selecting spermatozoa that retain motility for up to 24 h (1). An intrauterine insemination (IUI)-ready cryopreservation method using sucrose and glycerol-based cryoprotectant with Percoll processing produced improved results when compared to conventional cryopreservation (2). Additionally, selection of a highly motile sperm population by swim-up was shown to improve postthaw acrosomal integrity, motility, and other functional parameters (3). The purpose of this prospective study was to assess the impact of different semen processing methods (i.e., samples cryopreserved as whole semen and IUI-ready, and those washed for IUI after thawing) on motility parameters postthaw.
Patent•
09 Apr 2001TL;DR: In this paper, a method to determine sperm activity comprising the steps of contacting an appropriate concentration of human zona pellucida protein 3 with an appropriate amount of sperm under conditions permitting the formation of a complex between the human ZP protein and the sperm and determining the complex formed is presented.
Abstract: The present invention provides a method to determine sperm activity comprising the steps of: (a) contacting an appropriate concentration of human zona pellucida protein 3 with an appropriate amount of sperm under conditions permitting the formation of a complex between the human zona pellucida protein 3 and the sperm; and (b) determining the complex formed The invention further provides a method to determine sperm activity comprising the steps of (a) contacting an appropriate concentration of human zona pellucida protein 3 with an appropriate amount of sperm under conditions permitting an acrosome reaction to occur; and (b) determining the extent of the acrosome reaction Finally, this invention provides a diagnosis kit for sperm activity comprising three (3) compartments with (a) an appropriate amount of human zona pellucida protein 3; (b) the reagents used for establishing the conditions for allowing the binding of sperm; and (c) the reagents used for establishing the conditions for allowing an acrosome reaction
01 Jan 2001