Caranto G R, Waibel K H, Asher J M, Larrison R W, Brecht K M, Schutz M B, Raveh L, Ashani Y, Wolfe A D, Maxwell D M
Division of Biochemistry, Walter Reed Army Institute of Research, Washington, DC 20307-5100.
Biochem Pharmacol. 1994 Jan 20;47(2):347-57. doi: 10.1016/0006-2952(94)90026-4.
Pretreatment of rhesus monkeys with fetal bovine serum acetylcholinesterase (FBS AChE) provides complete protection against 5 LD50 of organophosphate (OP) without any signs of toxicity or performance decrements as measured by serial probe recognition tests or primate equilibrium platform performance (Maxwell et al., Toxicol Appl Pharmacol 115: 44-49, 1992; Wolfe et al., Toxicol Appl Pharmacol 117: 189-193, 1992). Although such use of enzyme as a single pretreatment drug for OP toxicity is sufficient to provide complete protection, a relatively large (stoichiometric) amount of enzyme was required in vivo to neutralize OP. To improve the efficacy of cholinesterases as pretreatment drugs, we have developed an approach in which the catalytic activity of OP-inhibited FBS AChE was rapidly and continuously restored, thus detoxifying the OP and minimizing enzyme aging by having sufficient amounts of appropriate oxime present. The efficacy of FBS AChE to detoxify several OPs was amplified by addition of bis-quaternary oximes, particularly 1-(2-hydroxyiminomethyl-1-pyridinium)-1-(4-carboxyaminopyridinium) -dimethyl ether hydrochloride (HI-6). When mice were pretreated with sufficient amounts of FBS AChE and HI-6 and challenged with repeated doses of O-isopropyl methylphosphonofluridate (sarin), the OP was continuously detoxified so long as the molar concentration of the sarin dose was less than the molar concentration of AChE in circulation. The in vitro experiments showed that the stoichiometry of sarin:FBS AChE was higher than 3200:1 and in vivo stoichiometry with mice was as high as 57:1. Addition of HI-6 to FBS AChE as a pretreatment drug amplified the efficacy of enzyme as a scavenger of nerve agents.
用胎牛血清乙酰胆碱酯酶（FBS AChE）对恒河猴进行预处理，可使其免受5倍半数致死剂量（LD50）有机磷酸酯（OP）的侵害，且无任何毒性迹象或性能下降，这通过系列探针识别测试或灵长类动物平衡平台性能得以衡量（Maxwell等人，《毒理学与应用药理学》115: 44 - 49, 1992；Wolfe等人，《毒理学与应用药理学》117: 189 - 193, 1992）。尽管将这种酶作为OP毒性的单一预处理药物足以提供完全保护，但体内需要相对大量（化学计量）的酶来中和OP。为提高胆碱酯酶作为预处理药物的疗效，我们开发了一种方法，其中被OP抑制的FBS AChE的催化活性能够快速且持续恢复，从而使OP解毒，并通过存在足够量的合适肟来最小化酶老化。通过添加双季铵肟，特别是1-(2 - 羟基亚氨基甲基 - 1 - 吡啶鎓)-1-(4 - 羧基氨基吡啶鎓)-二甲醚盐酸盐（HI - 6），FBS AChE对几种OP解毒的功效得以增强。当用足够量的FBS AChE和HI - 6对小鼠进行预处理，并反复给予O - 异丙基甲基膦酰氟化物（沙林）时，只要沙林剂量的摩尔浓度低于循环中AChE的摩尔浓度，OP就会持续解毒。体外实验表明，沙林与FBS AChE的化学计量比高于3200:1，而在小鼠体内的化学计量比高达57:1。将HI - 6添加到FBS AChE中作为预处理药物，增强了酶作为神经毒剂清除剂的功效。
