Tashiro M, Hirokawa K, Tada T, Nakajima T, Onoyama Y
OSAKA PREFECTURAL HABIKINO HOSP,HABIKINO,OSAKA 583,JAPAN. YODOGAWA CHRISTIANS HOSP,OSAKA 533,JAPAN.
Oncol Rep. 1996 Jul;3(4):723-7. doi: 10.3892/or.3.4.723.
In order to find radiosensitizers with low toxicity, radiation enhancing effects of the pentoxifylline (PENTO), which is known to bear so little toxicity as to be widely used for clinical purpose to improve peripheral blood circulation for vascular disorders, was compared with the nitroimidazole derivative SR 2508 (SR), which is an effective radiosensitizer but has severe neurotoxicity as do other nitroimidazole derivatives. We used an experimental tumor in mice and calculated an-enhancement ratio (ER) using a growth delay method. ER of PENTO and SR were 1.6 and 1.4, respectively, showing PENTO has stronger radiosensitizing effect than SR. Also combined effects with nicotinamide (NA) were compared between PENTO and SR. When combined with NA, the enhancing effects of PENTO was enhanced especially at lower radiation doses, whereas that of SR was decreased. Together with the fact that both PENTO and NA have very low toxicity, the usefulness of PENTO as a radiosensitizer either alone or combined with NA is suggested.
为了寻找低毒性的放射增敏剂，将己酮可可碱（PENTO）的辐射增强作用与硝基咪唑衍生物SR 2508（SR）进行了比较。己酮可可碱毒性极低，已被广泛用于临床以改善血管疾病的外周血液循环；而SR是一种有效的放射增敏剂，但与其他硝基咪唑衍生物一样具有严重的神经毒性。我们使用小鼠实验性肿瘤，并采用生长延迟法计算增敏比（ER）。己酮可可碱和SR的ER分别为1.6和1.4，表明己酮可可碱的放射增敏作用比SR更强。同时还比较了己酮可可碱和SR与烟酰胺（NA）的联合作用。当与NA联合使用时，己酮可可碱的增强作用尤其在较低辐射剂量下增强，而SR的增强作用则降低。鉴于己酮可可碱和NA两者毒性都很低，提示己酮可可碱单独或与NA联合作为放射增敏剂具有实用性。
