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

葡聚糖-氧化铁磁性液体(DM)是一种用于磁共振成像(MRI)的新型造影剂。DM作为治疗高热的辅助药物也备受关注。我们制备了三种不同葡聚糖衍生物与超细磁铁矿(Fe_3O_4)核组成的DM络合物：碱处理葡聚糖磁铁矿(ATDM)、羧甲基葡聚糖磁铁矿(CMDM)和羧甲基二乙氨基葡聚糖磁铁矿(CMEADM)。了解这些注射到活体体内的DM颗粒的行为对于磁共振成像和热疗的医学应用具有重要意义。因此，我们用光学显微镜(OM)和透射电子显微镜(TEM)以及脉冲核磁共振方法研究了DM在大鼠器官中的代谢和摄取。在本研究中，我们主要报道了CMEADM的结果，并与ATDM和CMDM进行了比较。静脉注射后对DM的核磁共振测量结果表明，L…更多地依赖于DM的微观结构，ATDM、CMDM和CMEADM的数值分别为1.5、2.8和9.2小时。OM观察和脉冲核磁共振测量发现，这些DM主要通过代谢在肝和脾中蓄积。注射1周后，柏林蓝铁反应在肝脏中检测不到CMEADM，表明CMEADM在3-4天内被从肝脏中取出。而在脾脏中，巨噬细胞摄取的CMEADM出现在红髓的边缘地带，并随着时间的延长移至边缘地带的外侧，12周后CMEADM不存在于边缘地带，而定位于红髓。透射电子显微镜观察显示，6周后，CMEADM颗粒被摄取到边缘区巨噬细胞的溶酶体中。巨噬细胞溶酶体中CMEADM的电子衍射图可归因于磁铁矿。然而，在12周后的样本中，观察到了无釉模式。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具有生物相容特性，并按照常规的铁代谢被红髓同化。较少

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