Document Detail

The effects of thrombocytopenia on vessel stasis and macromolecular leakage after photodynamic therapy using photofrin.
MedLine Citation:
PMID:  9337624     Owner:  NLM     Status:  MEDLINE    
Several studies have reported thrombus formation and/or the release of specific vasoactive eicosanoids, suggesting that platelet activation or damage after photodynamic therapy (PDT) may contribute to blood flow stasis. The role of circulating platelets on blood flow stasis and vascular leakage of macromolecules during and after PDT was assessed in an intravital animal model. Sprague-Dawley rats bearing chondrosarcoma on the right hind limb were injected intravenously (i.v.) with 25 mg/kg Photofrin 24 h before light treatment of 135 J/cm2 at 630 nm. Thrombocytopenia was induced in animals by administration of 3.75 mg/kg of rabbit anti-rat platelet antibody i.v. 30 min before the initiation of the light treatment. This regimen reduced circulating platelet levels from 300,000/mm3 to 20,000/mm3. Reductions in the luminal diameter of the microvasculature in normal muscle and tumor were observed in control animals given Photofrin and light. Venule leakage of macromolecules was noted shortly after the start of light treatment and continued throughout the period of observation. Animals made thrombocytopenic showed none of these changes after PDT in either normal tissues or tumor. The lack of vessel response correlated with the absence of thromboxane release in blood during PDT. These data suggest that platelets and eicosanoid release are necessary for vessel constriction and blood flow stasis after PDT using Photofrin.
V H Fingar; T J Wieman; P S Haydon
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Photochemistry and photobiology     Volume:  66     ISSN:  0031-8655     ISO Abbreviation:  Photochem. Photobiol.     Publication Date:  1997 Oct 
Date Detail:
Created Date:  1997-11-24     Completed Date:  1997-11-24     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0376425     Medline TA:  Photochem Photobiol     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  513-7     Citation Subset:  IM    
Department of Surgery, University of Louisville, KY, USA.
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MeSH Terms
Blood Platelets / drug effects,  physiology,  radiation effects
Capillary Permeability / drug effects,  radiation effects
Dihematoporphyrin Ether / toxicity
Microcirculation / drug effects,  physiopathology,  radiation effects
Photochemotherapy / adverse effects*
Photosensitizing Agents / toxicity
Rats, Sprague-Dawley
Thrombocytopenia / etiology*,  physiopathology
Vasoconstriction / drug effects,  radiation effects
Grant Support
Reg. No./Substance:
0/Photosensitizing Agents; 97067-70-4/Dihematoporphyrin Ether

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