Nuclear maturity of human spermatozoa selected by swim-up or by Percoll gradient centrifugation procedures

Protamine 2 precursors (Pre-P2), protamine 1 to protamine 2 ratio (P1/P2), and assisted reproduction outcome

“…Many independent groups reported initially a high P1/P2 ratio and altered seminal parameters in infertile patients (12,13,(18)(19)(20)(21)(22)(23)(24)(25). In our initial studies we also observed a proportion of samples with a decreased P1/P2 ratio (13), but we did not comment on this observation in our subsequent studies until the relationship of a decreased P1/P2 ratio with infertility was described (25).…”

“…Roughly equal amounts of P1 and P2 are considered normal in human spermatozoa (5,6,12,13). Many different studies have demonstrated the presence of an increased or a decreased protamine 1 to 2 ratio (P1/P2) in some infertile patients (6,12,13,(17)(18)(19)(20)(21)(22)(23)(24)(25)(26). Evidence for an increased amount of protamine 2 precursors (pre-P2) has also been reported in some infertile patients (16,22,23).…”

Effects of Cryopreservation on Sperm DNA Integrity in Normospermic and Four Categories of Infertile Males

“…Semen quality has been observed to be better preserved in fresh and cryopreserved semen processed through a PureSperm density gradient than swim-up. Higher recovery rates of mature motile sperm obtained after PureSperm sperm preparation may be beneficial for successful ART [Allamaneni et al 2005], having an improved nuclear maturity as assessed by microscopy [Le Lannou and Blanchard 1988;Colleu et al 1996] or flow cytometric (FCM) techniques [Molina et al 1995;Golan et al 1997;Spano et al 1999]. Cryopreservation of human semen in liquid nitrogen at À1961C is considered superior to mechanical freezing at À701C.…”

Sperm Nucleoproteins

“…An important question is whether the anomalies in protamine content found in some infertile patients are uniformly present in the different sperms in a sample or instead there are subpopulations within a single ejaculate different in protamine content. This subject has been studied both by measuring the effect of gradient centrifugation of spermatozoa on protamine content and through immunocytochemistry, indicating some degree of protamine heterogeneity within the cells of single samples [20,168,169].…”