Sperm-cell volumetric measurements as parameters in bull semen function evaluation: correlation with nonreturn rate.

Sperm-cell volume, measured electronically by cell counter, is a parameter providing information about the state and integrity of the plasma membrane by determining cell osmotic reactivity (swelling level). Electronic volume measurement is a modification of the hypo-osmotic swelling test, based on the increase in sperm volume in response to hypo-osmotic stress. In this study the volumetric method was applied to bull ejaculates, and the relationships of volumetric parameters, osmolality of seminal plasma, and concentration of sodium and potassium ions in seminal plasma, with the nonreturn rate (NRR) were examined. Significant correlations were found between volumetric parameters, conventional spermatological parameters, and NRR. The relative volume shift of the mean volume correlated significantly with motility before and after thawing (P < 0.05). NRR correlated significantly with iso-osmotic cell volume (- 0.49; P < 0.05) and with the relative volume shift (0.51, P < 0.05). The prediction level of regression models was improved when volumetric parameters (iso-osmotic cell volume) were included in the multiple regression model. Therefore, using electronic volume measurement as a component for fast, correct and valid (up to 50,000 cells), recording sperm-cell population may help to evaluate ejaculate quality more precisely.

Adenosine deaminase gene amplification in deoxycoformycin-resistant mammalian cells.

Deoxycoformycin (dCF)-resistant mutants of rat hepatoma, mouse LMTK-, and Chinese hamster ovary (CHO) cells have been isolated and shown to overproduce adenosine deaminase (ADA). The overproduction of ADA was found to be due to ADA-gene amplification in rat and mouse cells but not in CHO cells. Deoxycoformycin-resistant rat hepatoma cells have large HSRs (homogeneously staining regions), mouse cells carry DMs (Double minutes), and CHO cells do not appear to have any gross chromosomal anomalies. When dCF-resistant rat hepatoma and mouse cells are selected by increasing the concentration of the inhibitor in small increments, there is a good correlation between the increase in ADA gene copy number and the increase in the level of expression of ADA, suggesting that all of the amplified genes are equally active in the expression of ADA.