Ito S, Syundo J, Tsuji Y, Shimizu I, Kishi S, Tamura Y, Ii K, Xu Y
Second Department of Internal Medicine, School of Medicine, University of Tokushima, Japan.
Acta Histochem. 1988;83(1):99-105. doi: 10.1016/S0065-1281(88)80078-3.
Histochemical studies of human guanase (guanine deaminase) have seldom been undertaken, in part because of technical difficulties which result in heavy background staining. We reported a modified procedure for histochemical demonstration of guanase in human tissues involving hydrolytic deamination of the substrate guanine to xanthine via guanase, and then oxidation of xanthine to uric acid, with concomitant reduction of nitrotetrazolium blue (NBT). In this report, we describe a modification of this method for cytochemical demonstration of guanase at the fine structural level using yellow tetrazolium in place of NBT for determination of the intracellular distribution of guanase in human hepatocytes. In the hepatocytes, the reaction products were seen to be concentrated in the nucleus, in mitochondria, cisternae of the smooth and/or rough-surfaced endoplasmic reticulum, and lysosomes. The precise locations of the reaction product in the cisternae of the nuclear envelope, chromosomes, and nucleus could not be determined. However, the reaction products in the mitochondria were clearly seen to be located in the spaces of cristae. This information of the intracellular distribution of guanase in normal hepatocytes will be useful in determining the physiological role of this enzyme and in further studies on diseased hepatocytes including those in non-A non-B hepatitis.
对人鸟嘌呤酶（鸟嘌呤脱氨酶）的组织化学研究很少进行，部分原因是技术难题导致背景染色浓重。我们报告了一种用于在人体组织中进行鸟嘌呤酶组织化学显示的改良方法，该方法涉及通过鸟嘌呤酶将底物鸟嘌呤水解脱氨为黄嘌呤，然后将黄嘌呤氧化为尿酸，同时硝基四氮唑蓝（NBT）还原。在本报告中，我们描述了对该方法的一种改进，用于在精细结构水平上进行鸟嘌呤酶的细胞化学显示，使用黄色四氮唑代替NBT来确定人肝细胞中鸟嘌呤酶的细胞内分布。在肝细胞中，可见反应产物集中在细胞核、线粒体、光滑和/或粗糙内质网的池以及溶酶体中。无法确定反应产物在核膜池、染色体和细胞核中的精确位置。然而，线粒体中的反应产物清晰可见位于嵴间隙中。正常肝细胞中鸟嘌呤酶细胞内分布的这一信息将有助于确定该酶的生理作用，并有助于对包括非甲非乙型肝炎患者肝细胞在内的患病肝细胞进行进一步研究。
