Effects of Low-Dose Radiation on Repair Processes in Human Lymphocytes

No indications of an enhanced UV-light-induced unscheduled DNA synthesis in splenocytes of mice following a low-dose irradiation in vivo or in vitro

“…Although it is not known whether similarly stringent conditions are required for the induction of the effect in mouse lymphocytes, the dose and dose rate of the adapting dose applied in the present investigation lie, at least partly, in the required range of values. It should also be mentioned that Tuschl et al (1980Tuschl et al ( , 1983 observed an enhanced UV-light-induced UDS in lymphocytes of persons occupationally exposed to ionizing radiation at doses of 0.7-1.3 mSv/month and 0.14 mSv/month indicating that, under some circumstances, adapting doses applied at a very low dose rate may also be effective. Furthermore, the adapting dose conditions were not entirely different from those applied by Liu et al (1987) and Wojcik and Tuschl (1990), who, as mentioned above, did see an adaptive response.…”

“…The adaptive response to ionizing radiation is a phenomenon according to which cells pre-exposed to a low, adapting dose of ionizing radiation become refractory to a subsequent, higher radiation dose (Olivieri et al 1984;Shadley et al 1987;Tuschl et al 1980;Wolff et al 1991;Shadley and Dai 1993). It is generally assumed that the mechanism underlying the phenomenon involves the induction of a DNA repair system.…”

“…On the other hand, Sanderson and Morley (1986), Cai and Liu (1990) and Khandogina et al (1991) did find an adaptive response in G o lymphocytes irradiated in vitro. Furthermore, Tuschl et al (1980Tuschl et al ( , 1983 described an enhanced UV-light-induced unscheduled DNA synthesis (UDS) frequency and reduced mitomycin-C-induced sister chromatid exchanges in peripheral lymphocytes of persons occupationally exposed to low levels of ionizing radiation. Similarly, Liu et al (1987) and Wojcik and Tuschl (1990) found an augmented UV-light-induced UDS in lymphocytes of mice following an in vivo administration of the adapting dose.…”

An Examination of Radiation Hormesis Mechanisms Using a Multistage Carcinogenesis Model

“…Stecca and Gerber (1998) reviewed potential mechanisms of adaptive response including the activation of later genes that can promote production of growth factors and cytokines, trigger DNA repair, and regulate progress through the cell cycle. Tuschl et al (1980Tuschl et al ( , 1983 report an enhanced repair capacity for DNA damage after human occupational exposure to low doses of IR. For a more comprehensive review of studies about low-dose adaptations in biological responses at the cell, tissue, and organism levels, see, for example, Feinendegen and Pollycove (2001).…”

Können die Effekte der Radontherapie wissenschaftlich untermauert werden?

“…Darüber hinaus kommt es auch zu einer Stimulation jener Enzyme, die für die DNAReparaturmechanismen verantwortlich sind. Eine stimulierende Wirkung wiederholter niedrig dosierter Bestrahlung auf die Aktivität der DNA-Reparaturenzyme in Lymphozyten wurde bereits im Jahre 1980 von Tuschl et al beschrieben [10].…”