Shigeyuki Isaka

Detection of oxidative stress in seminal plasma and fractionated sperm from subfertile male patients

OBJECTIVES Oxidative stress in the reproductive system is thought to affect the fertilizing ability of sperm. Since 8-hydroxydeoxyguanosine (8-OHdG) and lipid peroxides are widely used as markers to quantify oxidative stress, we compared 8-OHdG and lipid peroxide concentrations in seminal plasma and spermatozoa from subfertile and fertile men. STUDY DESIGN Semen obtained from 37 men of subfertile couples (21 men with normozoospermia and 16 with asthenozoospermia) and from eight fertile volunteers were examined. Seminal plasma and spermatozoa were fractionated by four-step discontinuous Percoll gradient centrifugation. 8-OHdG in seminal plasma was measured by ELISA, and lipid peroxides in seminal plasma and spermatozoa were determined using a thiobarbituric acid (TBA) assay. RESULTS The concentrations of 8-OHdG and lipid peroxides in the seminal plasma of the subfertile group were significantly higher than those of the fertile group. There were no significant differences in these values between patients with normozoospermia and asthenozoospermia. In all four fractions obtained by Percoll gradient fractionation, the lipid peroxide levels in spermatozoa recovered from subfertile males were significantly higher than those of fertile controls. CONCLUSIONS Seminal plasma and spermatozoa from subfertile males showed elevated levels of oxidative stress that were detectable in ejaculated semen specimens by ELISA or TBA assay. Even the spermatozoa fraction considered to be mature and normal showed elevated oxidative stress in the subfertile group. Our results confirm the importance of oxidative stress in male reproductive function, and could be applied for the selection of patients for antioxidant therapy.

Mid-second trimester measurement of fetal nasal bone length in the Japanese population.

Aim:  We carried out a preliminary study to compare the nasal bone length (NBL) and biparietal diameter/NBL (BPD/NBL) ratio between the Japanese and white populations.

Isolation and characterization of a novel TP53-inducible gene, TP53TG5, which suppresses growth and shows cell cycle-dependent transition of expression

Through a strategy of direct cloning of TP53‐binding DNA sequences from human genome DNA, we have identified a novel TP53‐target gene, termed TP53TG5 (TP53‐target gene 5). This gene, localized to chromosome band 20q13.1 by fluorescence in situ hybridization, encodes a 290‐amino‐acid peptide with no significant homology with any known proteins in the public database. A colony‐formation assay using human glioblastoma cell line T98G, which lacks wild‐type TP53 and expresses no endogenous TP53TG5, revealed a growth‐suppressive effect of the TP53TG5 gene product. Furthermore, immunohistochemical studies, following transfection of T98G with plasmid designed to express green fluorescent protein‐fused TP53TG5, revealed cell cycle‐dependent intracellular localization of this protein. Our results suggest that functional studies of TP53TG5 may provide new insights into the complex physiological activities of TP53. Genes Chromosomes Cancer 27:345–352, 2000.