title: On the combination of photodynamic therapy with ionizing radiation.
abstract: Ehrlich ascites carcinoma growth and cell damage have been examined after photodynamic therapy (PDT), radiotherapy (RT) and combined treatment. Haematoporphyrin dimethyl ether (HPde) is used as a photosensitizer for PDT and tested as a radiosensitizer for RT. For PDT a non-coherent light source (370 < lambda < 680 nm) equipped with filters is used. gamma-Irradiation consists of 60Co irradiation at a dose of 2 Gy. Both PDT and RT induce a significant delay and inhibition in tumour growth (33 and 38%, respectively). Nevertheless cell damage after these treatments is different: after PDT the cell membrane integrity is damaged and no serious chromosomal aberrations are observed; whereas after gamma-irradiation there is no cell membrane integrity damage, but more significant DNA injuries are observed. It seems evident that HPde is able to act as a photosensitizer as well as a radiosensitizer. Combining PDT and RT produces an additive effect, not dependent on the sequence in which the two treatments are given, when a 1 h time window is used.
authors.affiliation: Lithuanian Oncology Centre, Laboratory of Laser and Photodynamic Therapy, Vilnius, Lithuania. zivile@loc.elnet.lt
authors.forename: Z
authors.initials: Z
authors.lastname: Luksiene
authors.forename: A
authors.initials: A
authors.lastname: Kalvelyte
authors.forename: R
authors.initials: R
authors.lastname: Supino
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D002286:Carcinoma, Ehrlich Tumor / Q000188:drug therapy* / Q000473:pathology / Q000532:radiotherapy*; D002455:Cell Division / Q000187:drug effects / Q000528:radiation effects; D002869:Chromosome Aberrations; D003037:Cobalt Radioisotopes; D003131:Combined Modality Therapy; D005720:Gamma Rays; D006415:Hematoporphyrins / Q000627:therapeutic use*; D051379:Mice; D008807:Mice, Inbred BALB C; D010778:Photochemotherapy; D011839:Radiation, Ionizing; D011838:Radiation-Sensitizing Agents / Q000627:therapeutic use*
chemical_list: D003037:Cobalt Radioisotopes; D006415:Hematoporphyrins; D011838:Radiation-Sensitizing Agents; C403716:hematoporphyrin diethyl ether