The purpose of this study was to determine the negative effects (cryodamage) on human spermatozoa after freeze-thawing and to determine whether freeze-thawing of spermatozoa with a programmed slow freezer is better than freezing with liquid nitrogen vapour (rapid freezing) with regard to alterations in sperm chromatin and morphology in semen from fertile (donor) and subfertile, IVF/ICSI, patients. Ninety-five semen samples were obtained either from patients attending our IVF unit for treatment (n=34) or from donors (n=25) with proven fertility and normal sperm quality according to WHO guidelines. Each semen sample was divided into two parts after liquefaction and addition of the cryoprotectant. The first part was frozen using a programmed biological freezer and the second part was frozen by means of liquid nitrogen vapour. Smears were made before the freezing and after the thawing procedure to assess morphology (strict criteria) and chromatin condensation (Acridine Orange test). The mean percentage of chromatin condensed spermatozoa in the samples from donors (control group) was 92.4 +/- 8.4% before freezing and this decreased significantly (p < 0.0001) to 88.7 +/- 11.2% after freeze-thawing with the computerized slow-stage freezer and to 87.2 +/- 12.3% after using static liquid nitrogen vapour (p < 0.001). The corresponding values for semen obtained from patients was 78.9 +/- 10.3% before freezing which decreased to 70.7 +/- 10.8 and 68.5 +/- 14.8%, respectively (p < 0.001). On the other hand, the mean percentage of normal sperm morphology in the control group decreased from 26.3 +/- 7.5% before freezing to 22.1 +/- 6.4% (p < 0.0001) after thawing with the computerized slow-stage freezer and to 22.2 +/- 6.6% (p < 0.0001) after the use of static liquid nitrogen vapour. In the patient group, the mean percentage of normal morphology decreased from 11.7 +/- 6.1% after freezing with the biological freezer to 9.3 +/- 5.6% and to 8.0 +/- 4.9% after freezing with static liquid nitrogen vapour. This study demonstrates that chromatin packaging and morphology of human spermatozoa decrease significantly after the freeze-thawing procedure, not only after the use of static liquid nitrogen vapour but also after the use of a computerized slow-stage freezer. However, the chromatin of semen samples with normal semen parameters (donor sperm) withstand the freeze-thaw injury better than those with low quality semen samples. Therefore, the computerized slow stage freezer could be recommended for freezing of human spermatozoa, especially for subnormal semen samples, for example, ICSI and ICSI/TESE candidates and from patients with testicular tumours or Hodgkin's disease, in order to avoid further damage to the sperm chromatin structure.

likely to have ever been employed by the armed forces (32.7% vs 11.7%, p<0.001).CONCLUSIONS: Most urologists learn on PT from the mass media. Education by framing PT as a means of improving the lives of injured veterans appears to improve urologists' attitudes. Various demographic differences exist in race and age that can inform educational efforts.

In general, the act of collecting semen for artificial insemination takes semen from its protected storage environment in the male and thrusts it into the unprotected environment of a specimen collection tube. Even with rapid processing, this leads to drastic shifts in temperature and pH, resulting in a quick deterioration of semen parameters and programmed cell death. This laboratory has developed a species-specific modified collection device (MCD), which was designed to optimize semen parameters by controlling temperature, pH and osmotic stress. In previous studies in the equine, canine, ovine and humans, using the new collection container/technique has resulted in improved semen parameters which are maintained over extended periods of time when compared to the traditional collection methods. Further, in a breeding trail in the equine, fertility rates of fresh semen were maintained for extended periods of time over the control. The objective of the current study was to further investigate the usefulness of the modified device in improving semen parameters and fertility rates in the bovine.

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