AN ULTRASTRUCTURAL COMPARATIVE EVALUATION OF TUMORS PHOTOSENSITIZED BY PORPHYRINS ADMINISTERED IN AQUEOUS SOLUTION, BOUND TO LIPOSOMES OR TO LIPOPROTEINS |
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Authors: | Chuannong Zhou Carla Milanesi Giulio Jori |
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Institution: | Cancer Institute, Chinese Academy of Medical Sciences, Beijing, People's Republic of China;department of Biology, The University of Padova, Italy |
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Abstract: | Abstract— Balb/c mice bearing a transplantedMS–2 fibrosarcoma have been injected with 2 mg kg-1 hematoporphyrin either dissolved in phosphate-buffered saline (Hp-aq), or incorporated into unilamellar liposomes of dipalmitoyl-phosphatidylcholine (Hp-lip), or precomplexed with low density lipoproteins (Hp-LDL). At 24 h after injection, the mice received 150 J cm-2 of600–680 nm light irradiation. Electron microscopic studies performed on tumor tissues taken from mice sacrificed at different times after the phototreatment showed that, in the presence of Hp-aq. tumor necrosis is largely the consequence of vascular damage. On the other hand, in the presence of Hp-lip and Hp-LDL, the response of the tumor to the phototreatment occurs at a faster rate and is mainly determined by direct damage of neoplastic cells. These findings are correlated with the different distribution of the various hematoporphyrin forms (Hp-aq, Hp-lip, Hp-LDL) among the serum proteins and the modalities of hematoporphyrin delivery to tissues by the possible carriers. |
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