RADIOLYSIS, PHOTOLYSIS AND SONOLYSIS OF CELLS AND THEIR CONSTITUENTS

声动力疗法是一种有前途的新的癌症治疗方式， 通过药物组合对细胞杀伤的协同作用 （通常是光敏剂）和超声。 梅村和同事们 提出声动力作用的机制包括： 通过声致发光光激发光敏剂（短 在空化气泡破裂期间发射的光脉冲）， 随后形成单线态氧。 理解机理 药物/超声协同作用的可能性是必要的进一步治疗 声敏疗法在肿瘤治疗中的应用。 电子 顺磁共振（EPR）研究了水 最有效的声动力学试剂镓的声化学反应， 卟啉衍生物（ATX-70）。 我们对温度影响的研究 和气体组成（N2/O2和N2/氩气混合物）不兼容， 梅村及其同事的单线态氧机制。 相反，我们发现 表面活性剂十六烷基三甲基溴化铵可以模拟这种效果， ATX-70 应注意，组合物的表面活性剂性质与表面活性剂的性质不同。 ATX-70中的卟啉环通过两个连接的C-10的存在而增强 店 我们目前关于表面活性剂在声动力学中作用的假设 细胞杀伤包括过氧自由基中间体的形成。的 非毒性浓度的声致敏细胞杀伤机制 的N，N-二甲基甲酰胺，N-甲基甲酰胺，和二甲亚砜， 通过EPR和使用自旋陷阱3，5-二溴-4- 亚硝基苯磺酸盐在氮饱和水溶液中的反应。 在空气中- 饱和水溶液中的碳中心的自由基转化为 相应的过氧自由基和自旋捕获与5，5-二甲基-1- 吡咯啉-N-氧化物（DMPO）。 这些激进的物种凭借其更长的 寿命和更高的选择性，相比OH自由基， 在超声处理的溶液中形成的，是负责声动力学的物种 用二甲基甲酰胺、单甲基甲酰胺或 二甲亚砜空泡溃灭的有效温度 用电子顺磁共振-自旋俘获法测量了多气泡场中的气泡， 利用苯基-叔丁基硝酮型自旋超声分解H2O/D2 O混合物 阱. 从半经典模型的温度依赖性的 动力学同位素效应的H和D的形成，我们估计的有效 在空穴区域中的温度，其中H和D原子是由 超声波诱导的水分子热解在 2000-4000 K。

Sonodynamic therapy is a promising new modality for cancer treatment based on the synergistic effect on cell killing by the combination of a drug (typically a photosensitizer) and ultrasound. Umemura and co-workers have proposed that the mechanism of sonodynamic action consists of the excitation of the photosensitizer by sonoluminescent light (the short pulses of light emitted during the collapse of cavitation bubbles) with subsequent formation of singlet oxygen. An understanding of the mechanism of drug/ultrasound synergism is essential for possible further therapeutic applications of sonosensitizing therapy in tumor treatment. Electron paramagnetic resonance (EPR) was used to investigate the aqueous sonochemical reactions of the most effective sonodynamic agent, gallium- porphyrin derivative (ATX-70). Our studies of the effect of temperature and gas composition (N2/O2 and N2/Argon mixtures) were not compatible with the singlet oxygen mechanism of Umemura and co-workers. Instead, we found that the surfactant cetyl-trimethylammonium bromide could mimic the effect of ATX-70. It should be noted that the surfactant properties of the porphyrin ring in ATX-70 are enhanced by the presence of two attached C-10 chains. Our current hypothesis of the role of surfactants in sonodynamic cell killing involves the formation of peroxyl radical intermediates. The mechanism of the sonosensitized cell killing by non-toxic concentrations of N,N-dimethylformamide, N-methylformamide, and dimethylsulfoxide was investigated by EPR and spin-trapping using the spin trap 3,5-dibromo-4- nitrosobenzene sulfonate in nitrogen-saturated aqueous solution. In air- saturated aqueous solutions the carbon-centered radicals were converted to the corresponding peroxyl radicals and spin trapped with 5,5-dimethyl-1- pyrroline-N-oxide (DMPO). These radical species by virtue of their longer lifetimes and higher selectivity, compared to OH radicals which are also formed in sonicated solutions, are the species responsible for sonodynamic cell killing with dimethylformamide, monomethylformamide, or dimethylsulfoxide. The effective temperature in collapsing cavitation bubbles in multi-bubble field was measured by EPR-spin trapping during the sonolysis of H2O/D2O mixtures using phenyl-t-butyl nitrone-type spin traps. From the semiclassical model of the temperature dependence of the kinetic isotope effect for H and D formation, we estimated the effective temperature in the cavitation region in which H and D atoms are formed by the ultrasound-induced pyrolysis of water molecules to be in the region of 2000-4000 K.