Human spermatids from ejaculate and testicular tissue have been utilized for evaluating human fertilization by intracytoplasmic sperm injection (ICSI) and, where possible, compared with spermatozoa utilizing sibling oocytes. Round and elongated spermatids obtained from ejaculates were either prepared through Percoll gradients or isolated and washed individually using subzonal insemination needl...

Between July 1995 and May 1996, 36 patients with non-obstructive azoospermia of secretory origin underwent intracytoplasmic injection of spermatids. A previous histological biopsy was performed on all patients: 15 had spermatogenic arrest, a further 13 had Sertoli cell-only syndrome, and the remaining eight had post-cryptorchidism tubal atrophy. The ejaculate was duly examined and a complete ab...

The clinical potential for fertilization was examined by using the human sperm-hamster oocyte assay system after microinjection of round (RS), elongating (ES) or elongated (EtedS) spermatids retrieved from obstructive and non-obstructive azoospermic patients. Freshly isolated, in-vitro cultured and cryopreserved spermatids were utilized. For each category of microinjected spermatids, we demonst...

BACKGROUND Round spermatid injections are associated with disappointing clinical outcomes, and although these cells have been shown to mature into late spermatids in vitro, the developmental potential of such gametes remains to be demonstrated. METHODS Round spermatids were isolated from 12 testicle samples of patients with obstructive azoospermia, hypoplasia, complete maturation arrest, and ...

BACKGROUND Recently we reported that an oocyte activation ability in human and mouse sperm is associated with head flatness or the presence of perinuclear theca (PT) substance, MN13, which is an oocyte activation-related protein localized on the post-acrosomal sheath (PAS). As such, we hypothesize that the appearance of oocyte activation ability is stage-specifically regulated and depends on th...

It has been shown that 5-thio-D-glucose (thioglucose) inhibits protein biosynthesis by highly purified fractions of immature spermatids (Zysk, Bushway, Whistler & Carlton, 1975; Nakamura & Hall, 1976). The inhibition occurs when thioglucose is added to spermatids in vitro or administered in vivo for as short a time as 2 days (Nakamura & Hall, 1976). Thioglucose is a chemical analogue ofglucose,...

BACKGROUND The use of immature male germ cells to fertilize human oocytes raises several questions. Spermatozoa are normally quiescent, but many genes are transcribed post-meiotically in round spermatids. This creates a novel situation for the oocyte. We have therefore explored the effects on early embryonic development of introducing a fully transcriptionally active round spermatid into the oo...