The Experts below are selected from a list of 267 Experts worldwide ranked by ideXlab platform
A Legreve - One of the best experts on this subject based on the ideXlab platform.
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comparative auto controlled study between swim up and Percoll preparation of fresh semen samples for in vitro fertilization
Human Reproduction, 1992Co-Authors: Yvon Englert, M Van Den Bergh, Cedric Rodesch, Edouard Bertrand, Jamila Biramane, A LegreveAbstract:This study compared swim-up and Percoll preparation of fresh semen samples for in-vitro fertilization. Sixty trials of in-vitro fertilization (IVF), 38 with normal semen and 22 with abnormal semen, comprising 734 oocytes were included in the study. Each semen sample was prepared by both a swim-up technique and a simplified discontinuous (50%, 70%, 90%) Percoll gradient. The oocytes for each trial were distributed at random between the two sperm preparations and incubated with the same number of motile spermatozoa. Percoll gradient preparation produced a significantly higher final concentration of spermatozoa than swim-up preparation (mean +/- SEM: 6.6 +/- 1.5 x 10(6)/ml versus 1.9 +/- 0.2 x 10(6)/ml; P less than 0.01) but a significantly lower sperm motility (69 +/- 2% versus 94 +/- 1%; P less than 0.001) and a lower number of normal forms (55 +/- 2% versus 64 +/- 2%; P less than 0.01). The ability of the Percoll gradient method to extract motile spermatozoa was higher than that of the swim-up technique (20 +/- 15.6% versus 0.8 +/- 13.6%). Nevertheless, the rates of fertilization (61%), fertilization failure (18%) and polyspermia (9%), embryo quality evaluated by mean embryo scores (3.8 +/- 0.3) and the mean number of spare embryos frozen per trial (1.4 +/- 0.3) were strictly identical in both groups. The 24 pregnancies (including three from frozen--thawed embryos) obtained in these 60 trials (40% per oocyte retrieval) could not be separated according to the sperm preparation method, as embryos from both groups were replaced together.(ABSTRACT TRUNCATED AT 250 WORDS)
M M Franco - One of the best experts on this subject based on the ideXlab platform.
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effect of Percoll volume duration and force of centrifugation on in vitro production and sex ratio of bovine embryos
Theriogenology, 2009Co-Authors: G M Machado, J O Carvalho, Siqueira E Filho, E S Caixeta, M M FrancoAbstract:Abstract The objective was to evaluate the effect of Percoll volume, and duration and force of centrifugation on sperm quality characteristics, embryo development, and sex ratio of in vitro-produced (IVP) bovine embryos. Frozen–thawed semen from four bulls were submitted to three Percoll procedures: T1—4 mL of Percoll, centrifuged for 20 min at 700 g; T2—800 μL of Percoll, centrifuged for 20 min at 700 g; and T3—800 μL of Percoll, centrifuged for 5 min at 5000 g. Sperm total motility, morphology and integrity of the sperm acrosome, membrane and chromatin were determined before and after Percoll treatment, and semen was used for in vitro fertilization (IVF) of in vitro-matured oocytes. All Percoll methods increased the proportion of motile sperm ( P P > 0.05), but were affected by sire ( P
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effect of Percoll volume duration and force of centrifugation on in vitro production and sex ratio of bovine embryos
Theriogenology, 2009Co-Authors: G M Machado, J O Carvalho, Siqueira E Filho, E S Caixeta, M M Franco, R RumpfAbstract:The objective was to evaluate the effect of Percoll volume, and duration and force of centrifugation on sperm quality characteristics, embryo development, and sex ratio of in vitro-produced (IVP) bovine embryos. Frozen-thawed semen from four bulls were submitted to three Percoll procedures: T1-4 mL of Percoll, centrifuged for 20 min at 700 g; T2-800 microL of Percoll, centrifuged for 20 min at 700 g; and T3-800 microL of Percoll, centrifuged for 5 min at 5,000 g. Sperm total motility, morphology and integrity of the sperm acrosome, membrane and chromatin were determined before and after Percoll treatment, and semen was used for in vitro fertilization (IVF) of in vitro-matured oocytes. All Percoll methods increased the proportion of motile sperm (P 0.05), but were affected by sire (P<0.05). Sex ratio was similar among treatments for Bulls 2 and 3, whereas semen from Bull 1 processed by T1 yielded a greater percentage of male embryos. However, when only treatments were considered, independent of bulls, the proportion of male:female embryos did not differ significantly from an expected 1:1 ratio. In conclusion, decreasing Percoll volume, reducing duration of centrifugation, and using a higher force of centrifugation did not significantly affect sperm quality, embryo development, or sex ratio of in vitro-produced bovine embryos.
Yvon Englert - One of the best experts on this subject based on the ideXlab platform.
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comparative auto controlled study between swim up and Percoll preparation of fresh semen samples for in vitro fertilization
Human Reproduction, 1992Co-Authors: Yvon Englert, M Van Den Bergh, Cedric Rodesch, Edouard Bertrand, Jamila Biramane, A LegreveAbstract:This study compared swim-up and Percoll preparation of fresh semen samples for in-vitro fertilization. Sixty trials of in-vitro fertilization (IVF), 38 with normal semen and 22 with abnormal semen, comprising 734 oocytes were included in the study. Each semen sample was prepared by both a swim-up technique and a simplified discontinuous (50%, 70%, 90%) Percoll gradient. The oocytes for each trial were distributed at random between the two sperm preparations and incubated with the same number of motile spermatozoa. Percoll gradient preparation produced a significantly higher final concentration of spermatozoa than swim-up preparation (mean +/- SEM: 6.6 +/- 1.5 x 10(6)/ml versus 1.9 +/- 0.2 x 10(6)/ml; P less than 0.01) but a significantly lower sperm motility (69 +/- 2% versus 94 +/- 1%; P less than 0.001) and a lower number of normal forms (55 +/- 2% versus 64 +/- 2%; P less than 0.01). The ability of the Percoll gradient method to extract motile spermatozoa was higher than that of the swim-up technique (20 +/- 15.6% versus 0.8 +/- 13.6%). Nevertheless, the rates of fertilization (61%), fertilization failure (18%) and polyspermia (9%), embryo quality evaluated by mean embryo scores (3.8 +/- 0.3) and the mean number of spare embryos frozen per trial (1.4 +/- 0.3) were strictly identical in both groups. The 24 pregnancies (including three from frozen--thawed embryos) obtained in these 60 trials (40% per oocyte retrieval) could not be separated according to the sperm preparation method, as embryos from both groups were replaced together.(ABSTRACT TRUNCATED AT 250 WORDS)
H Gordon W Baker - One of the best experts on this subject based on the ideXlab platform.
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comparison of Percoll mini Percoll and swim up methods for sperm preparation from abnormal semen samples
Human Reproduction, 1992Co-Authors: D Y Liu, H Gordon W BakerAbstract:Two methods of density gradient centrifugation, Percoll (P) and mini-Percoll (MP), were compared with the swim-up technique for preparing spermatozoa from each of 40 abnormal semen samples. P and MP produced similar results with a mean recovery of spermatozoa with progressive motility which was significantly higher (18-19%) than that achieved with swim-up (5%). However, the swim-up method resulted in the recovery of spermatozoa with a higher mean motility (89 versus 58%), velocity (69 versus 56 microns/s), percentage with normal morphology (22 versus 16%) and intact acrosomes (61 versus 36%) than P and MP. The mean amplitude of lateral head displacement was the only characteristic of spermatozoa in semen which correlated with the recoveries of motile spermatozoa. Combining MP and swim-up methods for 10 samples produced a higher recovery (11 versus 6.9%) of spermatozoa with significantly better mean motility (94 versus 87%) than did swim-up alone. Although P and MP resulted in greater yields of motile spermatozoa than the swim-up preparation, the latter procedure selected higher proportions of spermatozoa with improved characteristics (velocity, intact acrosomes and normal morphology) which correlate with fertilization rates in vitro. It is concluded that P and MP are not superior to swim-up. However, sequential MP and swim-up preparation improves yields of high quality spermatozoa from some abnormal semen samples and therefore has potential for improving fertilization rates.
James W. Overstreet - One of the best experts on this subject based on the ideXlab platform.
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separation of cryopreserved human semen using sephadex columns washing or Percoll gradients
Journal of Andrology, 1991Co-Authors: Erma Z Drobnis, Chang Q Zhong, James W. OverstreetAbstract:ABSTRACT: The following methods were evaluated for their ability to separate motile cryopreserved sperm from semen after thawing: single washing, Percoll separation followed by a single washing, and Sephadex column separation. For Sephadex separation, washing, and Percoll separation, percent recovery of motile sperm was 65%, 76%, and 28%, and motility was 81%, 39%, and 60%, respectively. Percoll separation and washing were the best methods for removing seminal constituents, but sperm velocity and linearity were lower after Percoll separation and washing than after Sephadex separation. During 3 hours of incubation, there was an additional decrease in the motility, viability (exclusion of supravital dye), velocity, linearity, and intact acrosomes of Percoll-separated sperm, indicating that Percoll separation may not be suitable for cryopreserved sperm. Motile, washed sperm also had lower velocities and higher spontaneous acrosome reactions than Sephadex-separated sperm, but velocity and linearity were maintained during incubation. When semen was separated with Sephadex followed by washing, motility was well maintained (84%). The Sephadex method is a promising technique for selecting and concentrating motile cryopreserved sperm.