5-Br-PADAP催化光度法测定锰的研究

实验中发现Mn（Ⅱ）能够催化5-Br-PADAP与过氧化氢之间的氧化还原反应，并找到了Mn^2＋浓度与催化褪色反应速度间的线性关系，线性浓度范围为0．5-10ng／mL，最小检出浓度为0．2ng／mL。方法灵敏度高，选择性好。     

锰增强MR功能成像在猫急性戊四氮致痫模型中的初步研究

目的应用锰增强MR功能成像（ME-fMRI）检测戊四氮（PTZ）诱发的猫急性癫痫模型的脑功能激活区，探讨ME-fMRI在脑功能成像方面的应用价值。方法40只家猫，采用随机数字表法分为癫痫A、B组与对照A、B组，癫痫A、B组肌内注射PTZ55ms／ks，诱发急性癫痫发作，对照A、B组肌内注射等量生理盐水。癫痫A组与对照A组用相同的方法观察其行为改变及行脑电图检查。癫痫B组与对照B组用相同的方法行ME-fMRI检查，测量感兴趣区不同时间的信号强度，计算增强率。结果癫痫A组均成功诱发急性癫痫发作。肌内注射PTZ后，癫痫B组ME-fMRI显示大脑皮层弥漫性明显对比增强，其中额顶枕叶脑皮层增强率达（34．6±5．7）％，颞叶皮层增强率达约（22．9±6．5）％，对照组分别为（14．9±4．5）％、（11．6±3．2）％，差异有统计学意义（t值分别为-10．43、-5．46，P值均〈0．05）。海马、脑室、脑白质、基底核团、面肌增强率2组差异无统计学意义（P〉0．05）。结论肌内注射PTZ 55mg／kg能成功诱发猫急性癫痫发作；ME-fMRI能准确反映该动物模型的脑功能激活区，具有直观性、可视性、空间分辨率高等优点，在研究脑功能方面具有极大的潜能。     

Manganese induced brain lesions inMacaca fascicularis as revealed by positron emission tomography and magnetic resonance imaging

A series of positron emission tomography scans was made on two monkeys during a 16-month period when they received manganese(IV)oxide by subcutaneous injection. The distribution of [¹¹C]-nomifensine uptake, indicating dopamine terminals, was followed in both monkey brains. The brain distributions of [¹¹C]-raclopride, demonstrating D₂ dopamine receptors, and [¹¹C]-l-dopa, as a marker of dopamine turnover, were followed in one monkey each. The monkeys developed signs of poisoning namely unsteady gait and hypoactivity. The [¹¹C]-nomifensine uptake in the striatum was reduced with time and reached a 60% reduction after 16 months exposure. This supports the suggestion that dopaminergic nerve endings degenerate during manganese intoxication. The [¹¹C]-l-dopa decarboxylation was not significantly altered indicating a sparing of [¹¹C]-l-dopa decarboxylation during manganese poisoning. A transient decrease of [¹¹C]-raclopride binding occurred but at the end of the study D₂-receptor binding had returned to starting values. The magnetic resonance imaging (MRI) revealed that the manganese accumulated in the globus pallidus, putamen and caudate nucleus. There were also suggestions of gliosis/edema in the posterior limb of the internal capsule. MRI might be useful to follow manganese intoxication in humans as long as the scan is made within a few months of exposure to manganese, i. e. before a reversal of the manganese accumulation.     

Brain MR imaging in patients with hepatic cirrhosis: relationship between high intensity signal in basal ganglia on T1-weighted images and elemental concentrations in brain

In patients with hepatic cirrhosis, the globus pallidus and putamen show high intensity on T1-weighted MRI. While the causes of this high signal have been thought to include paramagnetic substances, especially manganese, no evidence for this has been presented. Autopsy in four cases of hepatic cirrhosis permitted measurement of metal concentrations in brain and histopathological examination. In three cases the globus pallidus showed high intensity on T1-weighted images. Mean manganese concentrations in globus pallidus, putamen and frontal white matter were 3.03 ± 0.38, 2.12 ± 0.37, and 1.38 ± 0.24 (μg/g wet weight), respectively, being approximately four- to almost ten-fold the normal values. Copper concentrations in globus pallidus and putamen were also high, 50 % more than normal. Calcium, iron, zinc and magnesium concentrations were all normal. The fourth case showed no abnormal intensity in the basal ganglia and brain metal concentrations were all normal. Histopathologically, cases with showing high signal remarkable atrophy, necrosis, and deciduation of nerve cells and proliferation of glial cells and microglia in globus pallidus. These findings were similar to those in chronic manganese poisoning. On T1-weighted images, copper deposition shows no abnormal intensity. It is therefore inferred that deposition of highly concentrations of manganese may caused high signal on T1-weighted images and nerve cell death in the globus pallidus. Received: 12 August 1996 Accepted: 17 December 1996     

Radiation protects adriamycin-induced apoptosis

Combined radiotherapy and chemotherapy have represented major advance in the therapeutic management of cancer therapy. Anthracycline antineoplastic agents are limited by a high incidence of severe and usually irreversible cardiac toxicity, the cause of which remains controversial. When the primary cardiomyocytes isolated from neonatal rats were preirradiated by γ-ray, the cells were highly resistant to adriamycin-induced apoptosis. This study shows that irradiation inhibited apoptosis by enhancing Bcl-2, attenuating Bax induction, and preventing collapse of mitochondrial membrane potential (ΔΨ), cytochrome c release into cytoplasm and caspase-3, -6 and -9 activations.

In addition, the preirradiation stimulated the activity of manganese-superoxide dismutase (Mn-SOD) and the expression of Mn-SOD mRNA and protein. Adriamycin decreased Mn-SOD activity but did not change the activity of copper/zinc (Cu/Zn)-SOD under either pre- or nonirradiated condition. Phosphothioate-linked antisense against Mn-SOD, which specifically knocked down the activity of Mn-SOD but not that of Cu/Zn-SOD, reversed irradiation-induced protective effect in adriamycin-exposed cardiomyocytes. These data suggest that the irradiation-induced expression of Mn-SOD plays an important role in irradiation-mediated protection in adriamycin-exposed rat ventricular cardiomyocytes.     

血清锌、钙、锰含量对矮小儿童身高、骨龄的影响

目的:探讨血清锌、钙、锰含量对儿童身高、骨龄的影响。方法:用高频等离子体发射光谱法测定30例矮小儿童血清锌、钙、锰含量,同30例正常健康儿童比较。并进行锌、钙、锰与身高、骨龄相关分析。结果:矮小儿童血清锌、钙、锰含量明显低于对照组。相关分析发现,血清锌、钙、锰与身高呈明显正相关(P<0.01),血清锌、锰与骨龄呈明显正相关(P<0.01),而血清钙与骨龄无相关性(P>0.05)。结论:血清锌、钙、锰与儿童身高增长,骨龄成熟密切相关。     

锰中毒诊断和治疗研究进展

概括了近１０ 年国内外锰中毒诊断和治疗的研究进展。内容包括神经行为学、神经生化学、神经电生理学、免疫、内分泌指标和医学影像学技术在锰中毒诊断和鉴别诊断中的应用, 及目前用于临床锰中毒治疗的新药和新方法。     

Benign and malignant hepatocellular tumors: evaluation of tumoral enhancement after mangafodipir trisodium injection on MR imaging

The aim of this work was to study the ability of mangafodipir trisodium (Mn-DPDP)-enhanced MR imaging in differentiating malignant from benign hepatocellular tumors. Eleven patients with pathologically proved hepatocellular carcinomas, six with focal nodular hyperplasias, and one with a single hepatocellular adenoma were examined by spin-echo and gradient-echo T1-weighted sequences before, 1 h after, and 24 h after intravenous injection of Mn-DPDP (5 μmol/kg). Quantitative analysis including enhancement and lesion-to-liver contrast-to-noise ratio, and qualitative analysis including the presence of a central area and a capsule were done on pre- and post-Mn-DPDP-enhanced images. Enhancement was observed in all the tumors with significant improvement (p < 0.05) in contrast-to-noise ratio 1 h after, and 24 h after intravenous injection of Mn-DPDP. There were no significant differences in the mean enhancement and the mean contrast-to-noise ratio (CNR) between benign and malignant tumors. No enhancement was seen within internal areas observed in 7 hepatocellular carcinomas, and in 5 focal nodular hyperplasias, and within capsules which were observed in 9 hepatocellular carcinomas. In our study, Mn-DPDP increased CNR of both benign and malignant tumors but did not enable differentiation between benign and malignant tumors of hepatocellular nature. Received: 7 October 1997; Revision received: 25 February 1998; Accepted: 10 July 1998     

锰对大鼠子代新生鼠黑质酪氨酸羟化酶的影响

为了研究锰对子代新生鼠黑质中酪氨酸羟化酶（ｔｙｒｏｓｉｎｅｈｙｄｒｏｘｙｌａｓｅ,ＴＨ）的影响,对雌性大鼠腹腔注射氯化锰（ＭｎＣｌ２·４Ｈ２Ｏ）,然后采用原位杂交组织化学技术检测其子代新生鼠黑质中ＴＨ．ｍＲＮＡ神经元。结果：对照组新生鼠黑质中观察到ＴＨ．ｍＲＮＡ神经元,各实验组均未观察到ＴＨ．ｍＲＮＡ神经元。提示：锰在基因水平上抑制了染锰者子代新生鼠黑质中ＴＨ活性,进而干扰和抑制了胺能神经递质的正常代谢     

氯化锰致PC12细胞损伤的研究

探讨氯化锰（MnCl2）对PC12细胞的损伤作用。方法：构建MnCl2诱导的PC12细胞模型，用MTT法检测细胞存活率，用荧光分光光度法检测乳酸脱氢酶（LDH）和活性氧（ROS）生成量，用化学比色法测定细胞内丙二醛（MDA）含量和超氧化物歧化酶（SOD）活性。结果：MnCl2诱导的PC12细胞存活率明显下降，并与诱导时间和浓度呈正相关；MnCl2使PC12细胞LDH外溢量和ROS生成量显著增加，同时细胞内MDA含量增加，SOD活性下降。结论：MnCl2可导致PC12细胞的氧化损伤。