Selection of single-stranded deoxyribonucleic acid spermatozoa via the SpermPrep * filtration column

The fluorochrome acridine orange (AO) test was described by Tejada et al. (1) and provides chromatin heterogeneity information on the DNA content of a spermatozoa1 population. The test is based on the principle that the fluorochrome A0 when bound to the double-stranded normal DNA fluoresces green, whereas when bound to denatured, single-stranded DNA, fluoresces red. An abnormally high percentage of denatured DNA-containing spermatozoa that fluoresce red have been associated with decreased male fertility, whereas a high percentage of green fluorescing spermatozoa indicates a normal semen sample (2). It has also been shown that when the ratio of green fluorescent sperm is <45%, the prob-ability of oocyte fertilization is lower, whereas a ratio of green fluorescent sperm> 45 % indicates a higher probability of fertilization (2). A number of semen manipulative techniques are currently available to remove the undesirable sper-matozoa, debris, and other factors and to increase sperm quality before the performance of various as-sisted reproductive technologies (ART). Recently,