| pubmed-article:640049 | pubmed:abstractText | A further developed, practical device for human sperm freezing is described by which the preparation of sperm and the freezing process are reduced to a simple procedure requiring about 20 minutes. The instrument is based on the principle of evaporation of liquid nitrogen, which acts as a refrigerant for the freezing plate under the control of a thermostat. Rapid-rate freezing can be performed for pellet production and slow-rat freezing for paillettes; a high degree of isolation of samples is maintained by easily interchangeable freezing plates. Typical stages of freezing are accomplished at temperatures of +5 degrees C and--80 degrees C, with storage at--196 degrees C. The recovery index is 50% to 70%. The treatment was applied to 56 patients, resulting in 19 normal deliveries, 3 abortions, and 9 current pregnancies. | lld:pubmed |
