The Zona-Free Hamster Egg Penetration Test
1983; Linguagem: Inglês
10.1007/978-1-4471-3310-0_5
ISSN0177-8994
Autores Tópico(s)Reproductive System and Pregnancy
ResumoConventional methods of semen analysis rely heavily upon simple measurements of sperm quality which do not equate well with fertility. Of all the measurements routinely assessed (morphology, motility and sperm density) the greatest reliance is placed on sperm density since this shows a statistically significant correlation with infertility at concentrations below 60 million/ml (David et al. 1979) and densities of less than 10 million/ml are conventionally regarded as indicative of infertility. The predictive value of sperm density has been called into question however, for when the fertility of the female partner is taken into account about 50% of men with a sperm density of less than 10 million/ml can initiate a pregnancy (Smith et al. 1977) (see also Fig. 4.4). Thus direct tests of the fertilising capacity of an ejaculate are required in order to assess male infertility. The ideal assessment would be an in vitro fertilisation system incorporating mature human ova. However, because of the obvious logistical and ethical difficulties, such a direct test of fertilising capacity is only possible if some surrogate for the human ovum can be devised. The identification of such a surrogate has been achieved through the elegant studies of Yanagimachi at the University of Hawaii. The key to this discovery was the observation that guinea pig spermatozoa could be induced to penetrate hamster oocytes which had had the zona pellucida removed by trypsin treatment (Yanagimachi 1972).
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