Impact of pericentric inversion of Chromosome 9 [inv (9) (p11q12)] on infertility.

BACKGROUND: One of the frequent occurrences in chromosome rearrangements is pericentric inversion of the Chromosome 9; inv (9) (p11q12), which is consider to be the variant of normal karyotype. Although it seems not to correlate with abnormal phenotypes, there have been many controversial reports indicating that it may lead to abnormal clinical conditions such as infertility. The incidence is found to be about 1.98% in the general population. MATERIALS AND METHODS: We investigated the karyotypes of 300 infertile couples (600 individuals) being referred to our infertility clinic using standard GTG banding for karyotype preparation. RESULTS: The chromosomal analysis revealed a total of 15 (2.5%) inversions, among these, 14 male patients were inversion 9 carriers (4.69%) while one female patient was affected (0.33%). The incidence of inversion 9 in male patients is significantly higher than that of normal population and even than that of female patients (P< 0.05). CONCLUSIONS: This result suggests that inversion 9 may often cause infertility in men due to spermatogenic disturbances, which are arisen by the loops or acentric fragments formed in meiosis.

Development of a Noble Dosimetry Using Metaphase Analysis and Micronuclei Assay of Bone Marrow Cells in Mice / 대한핵의학회잡지

PURPOSE: The purpose of this study was to develop in vivo dosimetries using both chromosomal aberrations and micronuclei in mice to assess biological effects of radiations. MATERIALS AND METHODS: Five each mice were irradiated with 0, 1, 2, 3, 4, 5, 10 Gy of Cs-137 gamma-rays. We scored numbers of chromosomal aberrations in metaphase spreads and numbers of micronuclei in bone marrow smears under light microscope, and obtained the dose-response relationships. We also examined the relationship between the two dose-response curves. RESULTS: The frequency of both chromosomal aberrations and micronuclei increased with dose, in a linear-quadratic manner. The delta, beta, and alpha coefficients were 0.0176, 0.0324, and 0.0567 for metaphase analysis (r=1.0, p<0.001) and 0.0019, 0.0073, and 0.0506 for micronuclei assay (r=1.0, p<0.001). The frequency of chromosomal aberrations and micronuclei in diffirent radiation doses was significantly correlated (r=0.99, p<0.01). CONCLUSION: In vivo dosimetry using either metaphase analysis or micronucleus assay was feasible in mice. These methods could be useful to evaluate biological effects of radiation.

The Cytogenetic Effects of Benzene and Toluene on Bone Marrow Cells in Rats

Benzene and toluene have been widely employed as industrial solvents in Korea. However, they have recently been identified as cytogenetic toxic agents. This study is to observe the cytogenetic toxicities of benzene and toluene singularly and combined. The following concentrations of solvents were administered twice intraperitoneally to Sprague-Dawley rats: low concentration (11mg/Kg benzene and 108.75mg/Kg toluene), middle concentration (220mg/Kg benzene and (217.5mg/Kg toluene), and high concentration (440mg/Kg benzene and 435mg/Kg toluene). A low concentration represents the short term exposure limit of industrial workers. To examine the cytogenetic effects of the above solvents, the micronucleus test and the metaphase analysis were conducted followed by a statistical analysis based on non-parametric methods such as the Kruskal-Wallis multi sample test and the distribution free multiple comparison test A low concentration of benzene did not produce significant changes, however the two higher concentration of benzene showed clear signs of cytogenetic toxicities of bone marrow cells (i.e., the micronucleus occurrence rate and the chromosomal aberration rate were increased and the polychromatic erythrocyte percentage was decreased). While a low concentration of toluene produced no significant changes, the two higher concentrations of toluene showed similar signs of cytogenetic toxicities to bone marrow cells but to a somewhat lesser degree than benzene. When benzene and toluene were administered simultaneously at the two higher concentrations in order to observe their combined effects, all three signs of cytogenetic toxicities of bone marrow cells were decreased to a greater degree than the administration of benzene only. However, there were no significant reduction in the cytogenetic toxicities when benzene and toluene were simultaneously administered at low concentration. The above results showed that higher concentration of benzene and toluene displayed cytogenetic toxicities but showed competitive inhibition when they were administered simultaneously. However, there were no significant changes at low concentrations.