The objective of this study was to develop a relatively simple test to evaluate the functional integrity of the membranes of human spermatozoa. As in some other species, human spermatozoa 'swell' under hypo-osmotic conditions due to the influx of water and the expansion of the membranes. A mixture of equal parts of fructose and sodium citrate (150 mosmol) with calculated ionic strength of 0.15 resulted in a maximal number of clearly identifiable swollen spermatozoa. Only small variations were seen when different aliquants of the same semen samples were separately evaluated. A high correlation (r = 0.94) was obtained between expected and observed values of swollen spermatozoa when known amounts of heat-treated spermatozoa, unable to undergo swelling, were added to untreated spermatozoa. A good correlation (r = 0.90) was also observed between the % spermatozoa in a semen sample that were capable of undergoing swelling and the % of denuded hamster oocytes that were penetrated by capacitated spermatozoa from the same semen sample. By contrast, the correlations between % sperm swelling in ejaculates and % normal sperm forms, % motile spermatozoa and % spermatozoa that do not stain with eosin-Y (supravital stain) in the same ejaculates were 0.30, 0.61 and 0.52, respectively. Therefore, the hypoosmotic swelling technique to evaluate the functional integrity of the sperm membrane appears to give high repeatability and accuracy and is closely correlated to the in-vitro fertilizing ability of spermatozoa. It may be a useful addition to the standard semen analysis.

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Development of an assay to assess the functional integrity of the human sperm membrane and its relationship to other semen characteristics

Objective: To evaluate the empirical associations between alcohol use and risky sex at two levels of analysis. Global associations test whether individuals who engage in one behavior are more likely to engage in the other, whereas event-specific associations test whether the likelihood of engaging in one behavior on a given occasion varies as a function of engaging in the other on that same occasion. Methods: Studies examining the association between drinking and risky sex in samples of college students and youth were reviewed. Those published in the past 10 years and using event-level methodology or random sampling were emphasized. Results: Findings were generally consistent across levels of analysis, but differed across types of risky behaviors. Drinking was strongly related to the decision to have sex and to indiscriminate forms of risky sex (e.g., having multiple or casual sex partners), but was inconsistently related to protective behaviors (e.g., condom use). Moreover, the links among alcohol use, t...

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Alcohol use and risky sexual behavior among college students and youth: Evaluating the evidence

Role of reactive oxygen species in male infertility.

The spermatozoa of most invertebrates (e.g., sea urchins) and nonmammalian vertebrates (e.g., fishes and amphibians) have full capacity to fertilize eggs upon leaving the testis. Testicular spermatozoa of mammals, on the other hand, do not possess the ability to do so. Their fertilizing capacity develops as they pass through the epididymis (Young, 1931; Nishikawa and Waide, 1952; Blandau and Rumery, 1964; Bedford, 1966; Orgebin-Crist, 1967). This process, apparently “unique” to mammals, is referred to as the epididymal maturation of spermatozoa. Even after their maturation, however, spermatozoa require an additional phase of maturation or capacitation within the female genital tract before they are able to fertilize eggs (Austin, 1951, 1952; Chang, 1951a). Thus, epididymal maturation and capacitation are two extra steps that mammaliam spermatozoa must take before they can effect fertilization. In this chapter, I will discuss how mammalian spermatozoa prepare themselves for fertilization and how the spermatozoa and eggs interact during fertilization. The process and mechanisms of sperm transport in the female genital tract will not be dealt with extensively here. Readers are referred to Bishop (1961, 1969), Blandau (1969), Bedford (1970b, 1972b), Thibault (1972, 1973a), Zamboni (1972), Blandau and Gaddum-Rosse (1974), Hafez and Thibault (1975), Overstreet and Katz (1977), Overstreet and Cooper (1978, 1979b), Overstreet et al. (1978), Shalgi and Kraicer(1978), Cooper et al. (1979) and Hunter (1975, 1980). The rejection or elimination of extra spermatozoa by the fertilized egg, one of the most fascinating events in fertilization, will not be discussed here. Instead, readers are referred to the chapter by Dr. Wolf in this volume. The physiology of egg activation has been described and discussed to some extent by Gwatkin (1977) and Yanagimachi (1978a). There are numerous reviews dealing with general aspects of mammalian fertilization. The following are recommended to aid in grasping the outline of mammalian fertilization: Austin and Bishop (1957), Austin and Walton (1960), Austin (1961, 1968), Blandau (1961), Piko (1969), Thibault (1969), Bedford (1970a,b, 1972b), Gwatkin (1976, 1977), Yanagimachi (1977, 1978a), Bedford and Cooper (1978) and Hunter (1980).

Mechanisms of Fertilization in Mammals

In 1992 Carlsen et al. reported a significant global decline in sperm density between 1938 and 1990 [Evidence for Decreasing Quality of Semen during Last 50 Years. Br Med J 305:609-613 (1992)]. We subsequently published a reanalysis of the studies included by Carlsen et al. [Swan et al. Have Sperm Densities Declined? A Reanalysis of Global Trend Data. Environ Health Perspect 105:1228-1232 (1997)]. In that analysis we found significant declines in sperm density in the United States and Europe/Australia after controlling for abstinence time, age, percent of men with proven fertility, and specimen collection method. The declines in sperm density in the United States (approximately 1.5%/year) and Europe/Australia (approximately 3%/year) were somewhat greater than the average decline reported by Carlsen et al. (approximately 1%/year). However, we found no decline in sperm density in non-Western countries, for which data were very limited. In the current study, we used similar methods to analyze an expanded set of studies. We added 47 English language studies published in 1934-1996 to those we had analyzed previously. The average decline in sperm count was virtually unchanged from that reported previously by Carlsen et al. (slope = -0.94 vs. -0.93). The slopes in the three geographic groupings were also similar to those we reported earlier. In North America, the slope was somewhat less than the slope we had found for the United States (slope = -0.80; 95% confidence interval (CI), -1.37--0.24). Similarly, the decline in Europe (slope = -2.35; CI, -3.66--1.05) was somewhat less than reported previously. As before, studies from other countries showed no trend (slope = -0.21; CI, -2.30-1.88). These results are consistent with those of Carlsen et al. and our previous results, suggesting that the reported trends are not dependent on the particular studies included by Carlsen et al. and that the observed trends previously reported for 1938-1990 are also seen in data from 1934-1996.

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The question of declining sperm density revisited: an analysis of 101 studies published 1934-1996.

Analysis of Human Spermatozoal Fertilizing Ability Using Zona-Free Ova

The presence of white blood cells in semen has been associated with male infertility. Previous studies indicate that pyospermia occurs in conjunction with decreases in sperm motility, number of normal sperm forms, and penetration rates in the zona-free hamster egg sperm penetration assay. We have evaluated the relationship of seminal white blood cells and sperm function, as reflected in the zona-free hamster egg penetration assay, and have investigated the possible mode of action of the white cells. Egg penetration rates decreased when white blood cells from fertile or potentially fertile donors were added to their sperm suspensions prior to preincubation and at insemination in the in vitro assay. Zona-free hamster egg penetration assay results were also inhibited when the supernatant from white blood cells incubated in Biggers, Whitten, and Whittingham (BWW) medium overnight were introduced to sperm-oocyte suspensions at insemination. Conversely, egg penetration rates were enhanced in samples from hypofertile individuals when white blood cell concentrations in the semen or WBC/sperm ratios were reduced, either by physical removal or as a result of antibiotic therapy. The physical presence of leukocytes, and possibly, the extracellular release of lysosomal enzymes may be responsible for the inhibitory effects in vitro. Although the mechanism(s) by which white blood cells interfere with the fertilizing capacity of spermatozoa are not clear, it is quite obvious that their presence in the in vitro environment is undesirable and can mask an individual's actual fertilizing potential.

Effects of white blood cells on the in vitro penetration of zona-free hamster eggs by human spermatozoa.

A marathon: the immediate effect on female runners' luteinizing hormone, follicle-stimulating hormone, prolactin, testosterone, and cortisol levels

Funded in part by a grant from Kapiolani Medical Center for Women and Children, Honolulu, Hawaii. Presented at the Fifty-ninth Annual Meeting of the Pacific Coast Obstetrical and Gynecological Society, Ojai, California, October 1118, 1992.

Ralph W. Hale

Papers

Analysis of Human Spermatozoal Fertilizing Ability Using Zona-Free Ova

Effects of white blood cells on the in vitro penetration of zona-free hamster eggs by human spermatozoa.

A marathon: the immediate effect on female runners' luteinizing hormone, follicle-stimulating hormone, prolactin, testosterone, and cortisol levels

Funded in part by a grant from Kapiolani Medical Center for Women and Children, Honolulu, Hawaii. Presented at the Fifty-ninth Annual Meeting of the Pacific Coast Obstetrical and Gynecological Society, Ojai, California, October 1118, 1992.

Phasic approach to oral contraceptives.