Optimal utilization of cryopreserved human semen for assisted reproduction: recovery and maintenance of sperm motility and viability.

PURPOSE: Our purpose was to evaluate sperm motility and viability and the maintenance of these parameters in already cryopreserved semen samples following repeated freezing/thawing cycles. METHODS: Human spermatozoa were subjected to five cycles of cryopreservation/thawing. Recovery of sperm motility and viability and the proportion of viable nonmotile sperm were determined up to 6 hr after thaw. RESULTS: Sperm motilities (prefreeze motility, 70.1%; n = 9 samples) after each of five freeze/thaw cycles were 24.4, 8.0, 3.5, 1.5 and 1.8%. The recovery of sperm viability was higher than that of motility after each cycle: 39.1, 25.3, 22.6, 17.8, and 16.5%. Recoveries of motility and viability were improved if the thawed samples were left in the original cryopreservation medium prior to refreezing vs. if a washing/ resuspension step was included. The recovery of sperm motility in the first thawing cycle was indicative of the expected motile sperm recovery in the second thawing cycle. CONCLUSIONS: Cryopreserved semen that is intended to be reused in future assisted reproduction treatments should be thawed only once and aliquoted in the original freezing medium before refreezing. The recovery of sperm motility and viability in the second thawing cycle, thus the applicability of the sample in conventional in vitro fertilization or intracytoplasmic sperm injection may be anticipated in > 90% of the samples. In view of intracytoplasmic sperm injection it is important that sperm viability is maintained better than motility; after the first, second, and third thawing cycles the ratios of motile:nonmotile viable sperm were 1:1, 1:4, and 1:7, respectively.

Improving the intracytoplasmic sperm injection technique by transmembrane electric potential monitoring.

OBJECTIVE: To evaluate electrophysiologic techniques for transmembrane potential measurement during intracytoplasmic sperm injection (ICSI). DESIGN: Mature mouse oocytes were subjected to intracellular measurements of membrane potential using conventional techniques and modifications of the techniques for use with sham ICSI. During the procedure, the actual penetration of the membrane was determined subjectively or objectively with or without monitoring membrane potential. SETTING: Academic medical center. ANIMAL(S): Mouse. INTERVENTION(S): Measurement of oocyte membrane potential (Sham ICSI). MAIN OUTCOME MEASURE(S): Detectability of transmembrane potential using different electrodes and comparison of subjective and objective determination of membrane penetration. RESULT(S): Measurement of the membrane potential with the same glass pipettes used in ICSI means compromise between signal amplitude and compatibility with the conventional ICSI setup. Signal quality is related inversely to the diameter of the injection pipette, and its amplitude decreases as the concentrated electrode filling solution is replaced by physiologic solutions used in ICSI. When successful membrane penetration is suspected by visualization, measuring the potential at the tip of the injection pipette often proves otherwise. Conversely, when membrane penetration is confirmed by detection of transmembrane potential, the procedure may appear subjectively unsuccessful. CONCLUSION(S): Monitoring of transmembrane potential can be done successfully in conjunction with standard ICSI and has several potential applications.

Pregnancy in patients with cyclic neutropenia.

Cyclic neutropenia is characterized by periodic episodes of neutropenia that are often associated with infectious complications. A patient with cyclic neutropenia experienced two pregnancies with an amelioration of her infectious complications and an increase in neutrophil count. Cyclic neutropenia may follow a benign course during pregnancy.