Weerd-Kastelein, E.A. de

repair patient strain synthesis dna repair synthesis nuclei repair replication xp patients grain fusion level complementation xeroderma xp cells replication nucleus excision xeroderma pigmentosum table pigmentosum number cleaver cell strains light dna repair dna synthesis group exposure mutation population experiment irradiation paper excision repair control bootsma repair synthesis table i dimers result culture kleijer excision repair process disease defect xp strains labelling study xpzro enzyme process fibroblast amount repair dna synthesis mechanism patienten nature cellen pyrimidine dimers appendix weerd-kastelein xp cell strains keijzer atebrin staining pyrimidine gradient uv irradiation repair process cell populations atebrin autoradiographic exposure time xeroderma pigmentosum cells heterokaryon activity radioactivity syndrome complementation groups density lesion symptom