Abstract

The frequency of sister chromatid exchanges (SCE) was analysed in peripheral lymphocytes from patients receiving 8-methoxypsoralen (8-MOP) and longwave ultraviolet light (UVA) against psoriasis. The average SCE frequency in 14 patients after 3-10 weeks of clinical treatment did not differ statistically from that before treatment. UVA irradiation in vitro of blood from patients receiving 8-MOP caused a significant increase in the number of SCE. Such an increase was not observed after systemic administration of 8-MOP excluding UVA irradiation in vitro, nor after UVA irradiation in vitro in the absence of 8-MOP. Thus, the combination of oral 8-MOP administration and subsequent UVA irradiation in vitro promotes SCE in peripheral lymphocytes. However, this effect is not seen after clinical irradiation to the skin in vivo. The reason for this may be that the accumulated dose of UVA light in circulating lymphocytes, even after several weeks of clinical therapy, is not large enough to produce a significant amount of DNA damage leading to SCE, or else that DNA damage caused by the treatment is efficiency repaired during the intervals between treatments.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.