Improvement of XXXX response by manipulation of @entity5 oxygenation during photodynamic therapy.

@entity17654 @entity5 @entity19 @entity26 @entity519 @entity34
@entity34 ( @entity34 ) requires molecular @entity26 during light irradiation to generate reactive @entity26 species. @entity5 @entity519 , either preexisting or induced by @entity34 , can severely hamper the effectiveness of @entity34 . Lowering the light irradiation dose rate or fractionating a light dose may improve cell kill of @entity34 -induced @entity519 cells but will have no effect on preexisting @entity519 cells. In this study hyperoxygenation technique was used during @entity34 to overcome @entity519 . C3H @entity19 with transplanted mammary @entity5 were injected with 12.5 mg/kg @entity17654 and irradiated with 630 nm laser light 24 h later. @entity5 oxygenation was manipulated by subjecting the animals to 3 atp (atmospheric pressure) hyperbaric @entity26 or normobaric @entity26 during @entity34 light irradiation. The results show a significant improvement in @entity5 response when @entity34 was delivered during hyperoxygenation. With hyperoxygenation up to 80% of treated @entity5 showed no regrowth after 60 days. In comparison, when animals breathed room air, only 20% of treated @entity5 did not regrow. To explore the effect of hyperoxygenation on @entity5 oxygenation, @entity5 partial @entity26 pressure was measured with microelectrodes positioned in preexisting @entity519 regions before and during the @entity34 . The results show that hyperoxygenation may oxygenate preexisting @entity519 cells and compensate for @entity26 depletion induced by @entity34 light irradiation. In conclusion, hyperoxygenation may provide effective ways to improve @entity34 efficiency by oxygenating both preexisting and treatment-induced cell @entity519 .
