The biological effect of ionizing particles is caused mainly by water radicals being formed by densely ionizing ends of primary or secondary charged particles during physical stage; only greater radical clusters being efficient in DNA molecule damaging. The given clusters diffuse after their formation and the radical concentration changes also by reactions running mutually or with other substances being present in corresponding clusters. The damage effect depends then on radical concentrations at a time when the cluster meets a DNA molecule. The influence of oxygen may be important (mainly in the case of low-LET radiation) because oxygen is always present in living cells. Oxygen may act then in two different directions: at small concentrations the interaction with hydrogen radicals prevails and final biological effect diminishes while at higher concentrations additional efficient oxygen radicals may be formed. The time evolution of changing radical concentrations during cluster diffusion may be modeled and analyzed well with the help of Continuous Petri nets.
- Klíčová slova
- formace DSB, Petriho sítě, diferenciální rovnice, chemická fáze,
- MeSH
- ionizující záření * MeSH
- radiobiologie * MeSH
- teoretické modely MeSH
- Publikační typ
- práce podpořená grantem MeSH
Mathematical analytical model of the processes running in individual radical clusters during the chemical phase (under the presence of radiomodifiers) proposed by us earlier has been further developed and improved. It has been applied to the data presented by Blok and Loman characterizing the oxygen effect in SSB and DSB formation (in water solution and at low-LET radiation) also in the region of very small oxygen concentrations, which cannot be studied with the help of experiments done with living cells. In this new analysis the values of all reaction rates and diffusion parameters known from literature have been made use of. The great increase of SSB and DSB at zero oxygen concentration may follow from the fact that at small oxygen concentrations the oxygen absorbs other radicals while at higher concentrations the formation of oxygen radicals prevails. It explains the double oxygen effect found already earlier by Ewing. The model may be easily extended to include also the effects of other radiomodifiers present in medium during irradiation.
- MeSH
- bakteriofág phi X 174 genetika účinky záření MeSH
- biologické modely * MeSH
- chromozomy účinky léků účinky záření MeSH
- difuze účinky léků účinky záření MeSH
- dvouřetězcové zlomy DNA účinky léků účinky záření MeSH
- ionizující záření * MeSH
- kyslík farmakologie MeSH
- Publikační typ
- časopisecké články MeSH
- MeSH
- apoptóza účinky záření MeSH
- biologické modely MeSH
- buněčné linie MeSH
- Cricetulus MeSH
- DNA účinky záření MeSH
- fibroblasty fyziologie účinky záření MeSH
- financování organizované MeSH
- ionizující záření MeSH
- morčata MeSH
- počítačová simulace MeSH
- poškození DNA účinky záření MeSH
- statistické modely MeSH
- viabilita buněk účinky záření MeSH
- zvířata MeSH
- Check Tag
- morčata MeSH
- zvířata MeSH
- MeSH
- biologické modely MeSH
- lidé MeSH
- lineární přenos energie MeSH
- myši MeSH
- uhlík MeSH
- viabilita buněk účinky záření MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- srovnávací studie MeSH
