The problem of polyspermy in in vitro fertilization.

Polyspermy is a potential complication of attempts at in vitro fertilization. Nine polyspermic oocytes were identified among 169 oocytes obtained from 67 cycles stimulated by human menopausal gonadotropin. Cleavage to the 2-, 3-, and 4-cell stage was observed. Four polyspermic oocytes were identified among 85 oocytes obtained from 47 cycles stimulated by clomiphene citrate. Cleavage was not observed. Careful dispersion of cumulus cells at 15 to 18 hours and examination of the oocytes for polyspermy is essential, because the condition may not be apparent at 40 hours from insemination, when normal-appearing cleavage stages may be observed.

Combined screening laparoscopy and timed follicle aspiration for human in vitro fertilization.

Twenty-seven patients underwent ultrasonographic and clinical monitoring of a spontaneous cycle so that human chorionic gonadotropin administration could be timed in an attempt to schedule the screening laparoscopy at the optimal time for oocyte aspiration. Inadequate ovarian access was encountered in only 2 of 26 laparoscopies. Seven patients had ovulated by the time of scheduled laparoscopy. Nine mature, seven immature, and three postovulatory oocytes were obtained, and seven embryo transfers were accomplished. The number of eggs obtained per laparoscopy was 0.73. The attempt to control the time of ovulation was unpredictable, few mature oocytes were obtained, and the procedure offered little ultimate benefit to the patient.

Accumulation, nature, and possible functions of the malachite green affinity material in ejaculated human spermatozoa.

An electron microscopic study was conducted on human sperm over an incubation period of 5 to 6 hours in Tyrode's solution at room temperature. Examination of aliquots of the cells, fixed at timed intervals, with glutaraldehyde, malachite green, and postosmication revealed that malachite green affinity material (MGA-M) was barely discernible at first but did accumulate considerably upon standing. Biochemical analysis of MGA-M, which is extractable by glutaraldehyde, revealed that MGA-M is a mixture of extractable phospholipids and of their lyso-derivatives. Some of these substances have fusogenic properties; i.e., they are able to fuse together the membranes of two different cells. The appearance and accumulation of these fusogens occurred during the incubation period of 5 to 6 hours, which was previously shown to be required to capacitate human sperm in vitro. It is probable, therefore, that human sperm, during their initial period of incubation either in vivo or in vitro, not only become capacitated and undergo the acrosome reaction but also develop the fusogenic substance(s) which are necessary for the imminent fusion of their plasma membrane to the vitelline membrane of the mature oocyte.