OBJECTIVES/HYPOTHESIS: Delta @entity8454 (ALA)-induced @entity13880 ( @entity13880 ) is a fluorescent sensitizer that permits detection and treatment of @entity1544 . An exogenously induced decrease in tissue pH was evaluated for its effect in enhancing cellular uptake of ALA and facilitating its transformation into @entity13880 . STUDY DESIGN: @entity19 grafted with HT29 @entity694 had been given @entity413 and @entity6478 to modify the pH of tissues. Influence of pH changes has been evaluated on ALA-induced @entity13880 fluorescence by optic fiber spectrofluorimetry as well as on @entity5 growth. METHODS:                 <AbstractText Label="RESULTS" NlmCategory="RESULTS">The pH in HT 29 @entity5 decreased from 7.1 to 6.67 (P < .05) after intraperitoneal injection of @entity413 and @entity6478 . The @entity13880 fluorescence ratios in @entity5 or muscle before, between, and 2 hours after @entity413 and @entity6478 injection were not higher than control ratios. @entity8454 -photodynamic therapy was more efficient on HT 29 @entity5 -bearing @entity19 when the pH value was decreased with @entity413 and @entity6478 , showing a difference in the @entity5 growth index ratio from the 1st to 14th day of 22% between @entity6478 - @entity413 @entity8454 -photodynamic therapy and @entity8454 -photodynamic therapy alone (P < .05). CONCLUSIONS: @entity413 and @entity6478 did not change @entity13880 fluorescence in HT 29 @entity5 after intraperitoneal injection of @entity8454 but enhanced @entity8454 -photodynamic therapy efficacy. This was probably a result of mechanisms other than an increase in @entity8454 cellular penetration and @entity13880 production, such as susceptibility to free radical @entity137 or alteration of cellular repair enzymes under acidotic conditions. If a decrease of pH induces a more efficient photodynamic therapy as suggested by our results, an easier way to obtain this decrease than @entity413 and @entity6478 would be necessary for clinical applications.

Enhancement of delta XXXX -photodynamic therapy in vivo by decreasing @entity5 pH with @entity413 and @entity6478 .

@entity137 :: ('MESH:D064420', 'Disease') :: ['toxicity'] @entity19 :: ('10090', 'Species') :: ['mice', 'Mice'] @entity5 :: ('MESH:D009369', 'Disease') :: ['tumor'] @entity694 :: ('MESH:D003110', 'Disease') :: ['colonic cancers'] @entity6478 :: ('MESH:D000584', 'Chemical') :: ['amiloride'] @entity1544 :: ('MESH:D018307', 'Disease') :: ['squamous cell carcinoma of the oral cavity'] @entity13880 :: ('MESH:C028025', 'Chemical') :: ['PPIX', 'PpIX', 'protoporphyrin IX'] @entity8454 :: ('MESH:D000622', 'Chemical') :: ['aminolevulinic acid', 'Aminolevulinic acid'] @entity413 :: ('MESH:D005947', 'Chemical') :: ['glucose', 'Glucose']
@entity8454 :: (MESH:D000622,Chemical) :: ['aminolevulinic acid']
