Steven Green

Computer image sperm selection as a novel approach to subzonal insemination in the human

Utilizing real-time computer image analysis, individual spermatozoa were selected using microaspiration. Selection criteria were based on potential hyperactivation motility characteristics; the amplitude of lateral head displacement > 7.5 microns, curvilinear velocity > 70 microns/s and linearity of < 30%. For this pilot study, 16 patients (eight in each group) were recruited. Using subzonal insemination (SUZI), up to five (mean = 4.4 +/- 0.3) spermatozoa selected using computer-image sperm selection (CISS) were micro-injected, or up to 15 (mean = 12.8 +/- 1.3 SD) unselected spermatozoa. In the group which utilized CISS, 28 out of 49 (57%) oocytes were fertilized compared with 13 out of 52 (25%) utilizing conventional SUZI (P < 0.04); polyspermy was 20% (n = 10) and 2% (n = 1) respectively. CISS with SUZI showed increased efficiency in achieving fertilization and is a novel approach to studying individual sperm function in a sperm egg bioassay where gamete ratios are close to unity.

Injection Procedures of Immotile Sperm: Selection, Tail Breakage, and Viscous Solutions

The early microinjection of mammalian eggs began around the 1950s and 1960s with the work of Lin (1–3), who studied the technical experimental nature of egg “micrurgy” (4). This preceded the early studies in the mid-1960s that investigated the early events of fertilization using sperm microinjection in different species (5–7). The clinical use of this procedure sprang from the work of Palermo et al. in 1992 (8); however, attempts by numerous groups to achieve consistent and efficient results with intracytoplasmic sperm injection (ICSI) proved difficult. Initial concerns were focused on the control required to aspirate motile sperm in culture medium and manipulate its injection into the cytoplasm. Two problems were apparent: gaining control of the injection process and the injection of a motile sperm per se. ICSI is now a highly reproducible, efficient, and effective method of procuring fertilization, even with retrieved gamete ratios at unity. This chapter will describe the conditions under which ICSI should be performed to guarantee a high eff-ciency of fertilization and a low incidence of oocyte damage.