Orjih A U
MLS Department, Faculty of Allied Health Sciences, Kuwait University, Arabian Gulf.
J Pharmacol Exp Ther. 1997 Jul;282(1):108-12.
Plasmodium falciparum lysate, prepared from 2.7 x 10(7) ring-infected erythrocytes and incubated with hemoglobin in sodium acetate at pH 5, incorporated a mean of 1.6 nmol of ferriprotoporphyrin IX (FP) into hemozoin in 18 to 22 hr. A similar preparation of trophozoite lysate incorporated a mean of 3.6 nmol of FP into hemozoin in 4 to 6 hr. These findings indicate differences between heme polymerase activity (hemozoin production) at the ring and trophozoite stages of malaria parasites. Intracellular hemozoin production was 90% inhibited at the ring and trophozoite stages by 0.5 and 7 nmol of chloroquine/10(6) infected erythrocytes. respectively. The inhibition killed the rings but not the trophozoites, suggesting that mature parasites may have a mechanism for protecting themselves against chloroquine-FP toxicity.
恶性疟原虫裂解物由2.7×10⁷个环状感染红细胞制备而成，并在pH值为5的醋酸钠中与血红蛋白一起孵育，在18至22小时内平均将1.6 nmol的高铁原卟啉IX（FP）掺入疟色素中。类似制备的滋养体裂解物在4至6小时内平均将3.6 nmol的FP掺入疟色素中。这些发现表明疟原虫环状体和滋养体阶段的血红素聚合酶活性（疟色素产生）存在差异。在环状体和滋养体阶段，细胞内疟色素的产生分别被0.5和7 nmol氯喹/10⁶个感染红细胞抑制了90%。这种抑制作用杀死了环状体，但没有杀死滋养体，这表明成熟的寄生虫可能有一种机制来保护自己免受氯喹-FP毒性的影响。
