Results 371 to 380 of about 740,952 (392)
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Intracytoplasmic sperm injection and pregnancy with decapitated sperm
Fertility and Sterility, 2010To perform intracytoplasmic sperm injection (ICSI) in couples with primary infertility owing to sperm defects causing total immotility.Case report.Couple Sterility Center, University of Siena.Two infertile couples, the male members of which had "detached tail" genetic sperm defect.Physical and hormonal assays, semen analysis by light and electron ...
Gambera, Laura +6 more
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Sperm competition games: sperm selection by females
Journal of Theoretical Biology, 2003We analyse a co-evolutionary sexual conflict game, in which males compete for fertilizations (sperm competition) and females operate sperm selection against unfavourable ejaculates (cryptic female choice). For simplicity, each female mates with two males per reproductive event, and the competing ejaculates are of two types, favourable (having high ...
Geoff A. Parker, M.A. Ball
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Reviews of Reproduction, 1999
Communication between spermatozoa and egg before contact by chemotaxis appears to be prevalent throughout the animal kingdom. In non-mammalian species, sperm chemotaxis to factors secreted from the egg is well documented. In mammals, sperm chemotaxis to follicular factors in vitro has been established in humans and mice.
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Communication between spermatozoa and egg before contact by chemotaxis appears to be prevalent throughout the animal kingdom. In non-mammalian species, sperm chemotaxis to factors secreted from the egg is well documented. In mammals, sperm chemotaxis to follicular factors in vitro has been established in humans and mice.
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The sperm proteasome during sperm capacitation and fertilization
Journal of Reproductive Immunology, 2009The 26S proteasome is a multi-subunit protease specifically targeting ubiquitinated proteins. A consensus has emerged from studies by multiple laboratories on the role of sperm-borne proteasomes in human, mouse, pig, bovine, ascidian and echinoderm fertilization.
Peter Sutovsky, Shawn Zimmerman
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SPERM ACROSOME STATUS AND SPERM ANTIBODIES IN INFERTILITY
Journal of Urology, 1998We studied whether the spermatozoa from sperm autoimmune infertile men undergo premature acrosomal loss and whether this relates to the presence of sperm antibodies in wives.We evaluated acrosome status of live washed native and overnight capacitated spermatozoa from 17 sperm nonautoimmune fertile and 23 sperm autoimmune infertile men using an ...
Steven Harrison +2 more
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Sperm competition influences sperm size in mammals
Proceedings of the Royal Society of London. Series B: Biological Sciences, 1991Among mammals sperm competition leads to selection for increased sperm numbers but it is not known whether it also leads to changes in sperm size. Two contrasting theoretical predictions have been made. The first hypothesis relies on the assumption that there is a trade-off between sperm numbers and sperm size and predicts that, in species confronting ...
Eduardo R. S. Roldan +1 more
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Intracytoplasmic sperm injection
Molecular and Cellular Endocrinology, 2002Intracytoplasmic sperm injection (ICSI) with ejaculated, epididymal or testicular spermatozoa was first successful in 1992 and has since become the widely accepted treatment for couples with severe male-factor infertility. The outcome of several thousands of ICSI cycles in terms of fertilization, embryo cleavage and implantation is similar to that for ...
Van Steirteghem, André +2 more
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SPERM COMPETITION AND THE EVOLUTION OF NONFERTILIZING SPERM IN MAMMALS
Evolution, 1991Nonfertilizing sperm with special morphologies have long been known to exist in invertebrates. Until recently, abnormal sperm in mammals were considered errors in production. Now, however, Baker and Bellis (1988, 1989) have proposed that mammalian sperm, like some invertebrate sperm, are polymorphic and adapted to a variety of nonfertilizing roles in ...
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The risk of sperm competition and the evolution of sperm heteromorphism
Animal Behaviour, 1998Members of the Drosophila obscura species group exhibit sperm heteromorphism in which males simultaneously produce two different morphologies of sperm, short and long. Short sperm represent at least 50% of the ejaculate in several species but do not function in fertilization and thus, the evolutionary significance of this phenomenon is unknown ...
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SPERM COMPETITION AND ITS EVOLUTIONARY CONSEQUENCES IN THE INSECTS
, 1970Geoff A. Parker
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