Brem Franziska, Hirt Ann M, Winklhofer Michael, Frei Karl, Yonekawa Yasuhiro, Wieser Heinz-Gregor, Dobson Jon
Institute of Geophysics, ETH-Hönggerberg, 8093 Zurich, Switzerland.
J R Soc Interface. 2006 Dec 22;3(11):833-41. doi: 10.1098/rsif.2006.0133.
Iron is a central element in the metabolism of normal and malignant cells. Abnormalities in iron and ferritin expression have been observed in many types of cancer. Interest in characterizing iron compounds in the human brain has increased due to advances in determining a relationship between excess iron accumulation and neurological and neurodegenerative diseases. In this work, four different magnetic methods have been employed to characterize the iron phases and magnetic properties of brain tumour (meningiomas) tissues and non-tumour hippocampal tissues. Four main magnetic components can be distinguished: the diamagnetic matrix, nearly paramagnetic blood, antiferromagnetic ferrihydrite cores of ferritin and ferrimagnetic magnetite and/or maghemite. For the first time, open hysteresis loops have been observed on human brain tissue at room temperature. The hysteresis properties indicate the presence of magnetite and/or maghemite particles that exhibit stable single-domain (SD) behaviour at room temperature. A significantly higher concentration of magnetically ordered magnetite and/or maghemite and a higher estimated concentration of heme iron was found in the meningioma samples. First-order reversal curve diagrams on meningioma tissue further show that the stable SD particles are magnetostatically interacting, implying high-local concentrations (clustering) of these particles in brain tumours. These findings suggest that brain tumour tissue contains an elevated amount of remanent iron oxide phases.
铁是正常细胞和恶性细胞代谢中的核心元素。在许多类型的癌症中都观察到了铁和铁蛋白表达的异常。由于在确定过量铁积累与神经和神经退行性疾病之间的关系方面取得了进展，人们对表征人脑中的铁化合物的兴趣增加了。在这项工作中，采用了四种不同的磁性方法来表征脑肿瘤（脑膜瘤）组织和非肿瘤海马组织的铁相和磁性特性。可以区分出四种主要的磁性成分：抗磁性基质、近顺磁性血液、铁蛋白的反铁磁性水铁矿核心以及亚铁磁性磁铁矿和/或磁赤铁矿。首次在室温下在人脑组织上观察到开放磁滞回线。磁滞特性表明存在在室温下表现出稳定单畴（SD）行为的磁铁矿和/或磁赤铁矿颗粒。在脑膜瘤样本中发现了磁性有序的磁铁矿和/或磁赤铁矿的浓度显著更高，以及血红素铁的估计浓度更高。脑膜瘤组织的一阶反转曲线图进一步表明，稳定的SD颗粒存在静磁相互作用，这意味着这些颗粒在脑肿瘤中具有高局部浓度（聚集）。这些发现表明脑肿瘤组织中残留的氧化铁相含量升高。
