title: Effect of low-dose X-ray irradiation on micronucleus formation in human embryo, newborn and child cells.
abstract: It is well known that a high-dose of ionizing radiation is sufficient to break DNA strands, which leads to elevated genotoxic risks; however, the risks associated with low doses of ionizing radiation remain unclear. In addition, there is little data about the effect of low-dose ionizing radiation on human-derived embryo, newborn and child cells. We investigated the frequency of micronucleus (MN) formation in these cells to understand the genotoxic effects of ionizing radiation.
  
  
  
  We irradiated the cells with X-rays from 0.02-2 Gy at a rate of 0.0635 Gy/min. After irradiation, we investigated the effect of low-dose X-ray irradiation on cellular viability and frequency of MN formation.
  
  
  
  Increases in MN formation were largely dose-dependent; however, there were no differences between controls and doses lower than 0.2 Gy, except in KMST-6 human transformed embryo cells.
  
  
  
  We could not detect an obvious effect of low-dose X-ray irradiation at doses lower than 0.1 Gy. The embryonic cells were more sensitive to X-ray irradiation than newborn and child cells. The threshold for X-ray-induced MN formation appears to be in the range of 0.05-0.1 Gy in cultured human embryo, newborn and child cells.
authors: a Laboratory of Applied Radio Engineering for Humanosphere, Research Institute for Sustainable Humanosphere, Kyoto University , Gokasho, Uji, Kyoto , Japan.
authors: Shin
authors: S
authors: Koyama
authors: a Laboratory of Applied Radio Engineering for Humanosphere, Research Institute for Sustainable Humanosphere, Kyoto University , Gokasho, Uji, Kyoto , Japan.
authors: Eijiro
authors: E
authors: Narita
authors: a Laboratory of Applied Radio Engineering for Humanosphere, Research Institute for Sustainable Humanosphere, Kyoto University , Gokasho, Uji, Kyoto , Japan.
authors: Naoki
authors: N
authors: Shinohara
authors: a Laboratory of Applied Radio Engineering for Humanosphere, Research Institute for Sustainable Humanosphere, Kyoto University , Gokasho, Uji, Kyoto , Japan.
authors: Junji
authors: J
authors: Miyakoshi
mesh_terms: D000375:Aging / Q000528:radiation effects*; D002470:Cell Survival / Q000235:genetics / Q000528:radiation effects*; D002648:Child; D004307:Dose-Response Relationship, Radiation; D004622:Embryo, Mammalian / Q000166:cytology* / Q000528:radiation effects*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D048629:Micronuclei, Chromosome-Defective / Q000528:radiation effects*; D011829:Radiation Dosage; D014965:X-Rays / Q000009:adverse effects*
keywords: Cellular genotoxicity; X-rays; low-dose; micronucleus (MN)