Human spermatozoa are usually prepared for in vitro fertilization (IVF) by centrifugal washing and incubation in albumin based media. This is an inefficient technique contributing to poor IVF prospects, false-negative scores in the sperm penetration assay (SPA), and inadequate quantification in the sperm chromosome assay (SCA). High yields of fusiogenically functional sperm were rapidly and efficiently prepared by exposing sperm suspensions to an electrical pulse of 750 to 1500 V cm-1 for 2.5 msec. This process was calcium-dependent, and sperm incorporation into zona-free hamster eggs exhibited a linear relationship with Ca2+. At voltages greater than 1500 V cm-1, penetration declined. Sperm from subfertile men demonstrated significantly increased penetration after electropermeabilization. Sperm development was not hindered and in the SCA, yields of sperm metaphases approaching 100% were achievable.

The prognostic value of the sperm penetration assay (SPA) using zona-free hamster ova has not been universally accepted. This is partly due to technical problems with the assay, resulting in 5-17% false negative results. The advantage of replacing albumin with defined synthetic polymers in the SPA culture media, increasing the calcium gradient and incorporating potential active tract agents and antioxidants, has been investigated. These studies have resulted in the development of a procedure that has produced no negative results among known fertile donors (n = 55). Application of this technique to a non-specific group of patients with suspected sub-fertility produced a different pattern of sperm penetration compared with the 'standard' SPA in 27% of cases. Improved sperm velocity, motile survival, enhanced hyaluronidase release and rate of acrosome induction were noted using the synthetic media.

A simple and inexpensive rat diuresis cage is described. It may be constructed from thin aluminium sheeting in combination with a standard laboratory holding cage. Application of a low resistance PTFE coating reduces urine losses to a level better than a leading commercial design. Some physiological strain comparison data obtained using the cage are given.

An open-field instrument is described utilising a versatile rsistance detection system for measuring ambulation in mice and rats. The ambulation detector may sense horizontal and vertical ambulation or horizontal, vertical and diagonal ambulation in the ground plane, depending on mode selection. In addition, it can respond to an animal's presence on particular plates or areas in a ‘touch toggle’ fashion. A separate circuit records height selected rears by way of capacitance effects. The rearing detection surface consists of a moveable perforated metal grid above the open-field. The complete open-field system is controlled by a process-timer and facilities for ‘real time’ recording are incorporated. Details of accuracy, reliability and mode of use are reported.