Biological behavior of dextran-iron oxide magnetic fluid iv-injected into rats.

右旋糖酐-氧化铁磁流体（DM）是一种新型磁共振成像造影剂。右美沙芬作为高热症的辅助药物也引起了人们的广泛关注。我们制备了三种由不同葡聚糖衍生物和超细磁铁矿（Fe_3O_4）芯组成的DM配合物：碱处理葡聚糖磁铁矿（ATDM）、羧甲基葡聚糖磁铁矿（CMDM）和羧甲基二乙胺葡聚糖磁铁矿（CMEADM）。了解这些DM颗粒注入活体后的行为对MRI和高热症的医学应用具有重要意义。因此，通过光学显微镜（OM）和透射电镜（TEM）以及脉冲核磁共振方法研究了大鼠各器官中DM的代谢和摄取。在本研究中，我们主要报道CMEADM的结果，并与ATDM和CMDM的结果进行比较。静脉注射后DM的核磁共振测量结果表明，血液清除的一半时间在很大程度上取决于DM的微观结构，ATDM、CMDM和CMEADM的数值分别为1.5、2.8和9.2 h。从OM观察和脉冲核磁共振测量中发现，这些DM主要通过代谢在肝脏和脾脏中积累。注射1周后，经柏林蓝铁反应，CMEADM在肝脏中未被检测到，提示CMEADM在3 - 4天内从肝脏中被清除。而在脾脏中，巨噬细胞摄取的CMEADM位于红髓边缘区，并随着时间的增加向边缘区外侧移动，12周后CMEADM在边缘区不复存在，位于红髓。透射电镜观察显示，6周后样品巨噬细胞的边缘区溶酶体中出现了CMEADM颗粒。巨噬细胞溶酶体中存在的CMEADM的电子衍射图归因于磁铁矿。然而，对于12周后的样品，观察到非晶态图案。在注射后相对较短的时间内，肝组织也有类似的代谢过程。可以得出结论，DM具有生物相容性，并在红浆中被同化，符合常规铁代谢。少

Dextran-iron oxide magnetic fluid (DM) has been developed as a new type of contrast agent designed for magnetic resonance imaging (MRI). the DM is also attracted much attention as an auxiliary agent in hyperthemia. We have prepared three kinds of DM complex consisting of the different dextran derivatives and a ultra-fine magnetite (Fe_3O_4) core : i.e., alkali-treated-dextran -magnetite (ATDM), carboxy-methyl-dextran-magnetite (CMDM), and carboxymethyl-diethylamino-dextran-magnetite (CMEADM). The knowledge about behavior of these DM particles injected into living body is important for medical use in MRI and hyperthemia. Thus, metabolism and taking-up of the DM in rat organs is investigated by the optical microscope (OM) and transmission electron microscope (TEM), as well as pulse NMR method. In this study, we report mainly the results of CMEADM,in comparison with those of ATDM and CMDM.The results of NMR measurements of DM after iv-injection show that the half time of blood clearance l … More argely depends on the microstructure of the DM and the values are 1.5,2.8 and 9.2 hours for ATDM,CMDM and CMEADM,respectively. It has been found from OM observation and pulse NMR measurments that these DM are mostly accumlated in the liver and spleen through the metabolism. After 1 week from injection, the CMEADM could not be detected in the liver by the Berlin blue iron reaction, suggesting that they was removed from the liver within three-four days. While in spleen, the CMEADM taken-up in the macrophage is observed at the marginal zone of red pulp and moves to the outer-part of the marginalzone with increase in time elapsing, and after an elapse of 12 weeks the CMEADM does not exist in the marginal zone and locates in the red pulp. The TEM observation revealed that the CMEADM particles are taken-up in the lysosoms of macrophage at the marginal zone for the samples after 6 weeks. The electron diffraction patterns from the CMEADM which exists in the lysosomes of macrophage was attributable to magnetite. However, for the samples after 12 weeks, the amolphous pattern were observed. The similar metabolic process has been also recognized for liver tissue within a relatively short period of time after injection. One might conclude that the DM has the biocompatible character and is assimilated in the red pulp in compliance with the conventional iron metabolism. Less