Human sperm cryobanking. Use of modified liquid nitrogen vapor.
OBJECTIVE
To study a modified liquid nitrogen vapor cryopreservation technique for human spermatozoa.


METHODS
The freezing rate of the modified liquid nitrogen vapor method was controlled using thermocouple probes to simultaneously measure the temperature of both the liquid nitrogen vapor and semen specimen. Sperm cryosurvival and postthaw velocity were compared using a programmable biologic freezer and our modified vapor freezing procedure.


RESULTS
There were no significant differences in postthaw sperm viability between the two methods.


CONCLUSIONS
This modified vapor freezing technique permits controlled cooling that is efficient, rapid and inexpensive.
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Faulkner Centre for Reproductive Medicine, Harvard/Deaconess Surgical Program, Faulkner Hospital, Boston, Massachusetts, USA.
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D015925:Cryopreservation / Q000379:methods*; D005069:Evaluation Studies as Topic; D006801:Humans; D008297:Male; D009584:Nitrogen; D013074:Sperm Banks; D013094:Spermatozoa; D016019:Survival Analysis; D013696:Temperature
D009584:Nitrogen