甲巯咪唑在酞菁钴修饰碳糊电极上的示差脉冲伏安法测定

目的:研究甲巯咪唑在酞菁钴(CoPc)修饰碳糊电极上的电化学行为并测定其含量。方法:循环伏安(CV)法和示差脉冲伏安(DPV)法。结果:在 pH=7.0、修饰电极中 CoPc 含量为6.25%(w/w)、富集电位-0.3 V(vs SCE)、富集时间40 s 的条件下,甲巯咪唑的氧化峰电流(i_p)与其浓度在2.0×10~(-6)～7.0×10~(-4)mol·L~(-1)范围内呈良好的线性关系,检出限为0.3 μmol·L~(-1)。结论:该方法应用到实际样品含量测定,其结果令人满意。     

缺血修饰白蛋白的分光光度法检测及临床意义

目的建立一个白蛋白结合钴(albumin cobalt binding,ACB)试验检测IMA。方法ACB试验是用分光光度测定法,结果以吸光度单位(absorbance Units,ABSU)报告。结果在470nm测定的平均ABSU±s,对照组和心肌缺血级分别为:(0.336±0.084)和(0.586±0.087)(P<0.01)。结论ACB试验可用作评价心肌缺血有用的诊断工具,测定值>0.504时可认为缺血阳性。     

正常人和食管癌患者食管组织微量元素分析

用原子吸收分光光度法测定了50例食管癌患者和16例正常人食管组织中微量元素铜、锌、铁、钴、锰、镍的含量。结果:①食管癌组织铜含量明显高于癌旁组织、余差异无显著性;②正常人食管组织锰、钴高于食管癌组织及癌旁组织,铜低于癌组织,但与癌旁组织差异无显著性。作者认为.食管癌组织铜含量升高可能是癌变的结果。食管癌病人食管组织锰、钴低于正常人有可能是癌变原因之一。     

Scanning electron microscopy of the metal-tissue interface: II Observations with lead,copper, nickel,aluminium, and cobalt

The nature of the metal-tissue interface following the implantation of five pure metals, lead, copper, nickel, aluminium and cobalt, in rats has been observed by scanning electron microscopy. The general conculsion, derived from light microscopy that the tissue response to pure metals is characteristic of and specific to individual pure metals has been confirmed in this study. However, far more detailed observations of factors such as the extent of metallic corrosion, the distribution of red blood cells, platelets and other cells in the capsule and adherent to the metal surface, have been possible with SEM.     

Electrophysiological abnormalities in chronic epileptogenic foci: an intracellular study

Intracellular recordings were performed from chronic cobalt epileptogenic foci in rats. Two main features were found: (a) in 29% of the neurons, large depolarizations of long duration occurred coinciding with cortical surface paroxysms; and (b) in 13% of the neurons, partial spikes, whose amplitude varied little with membrane DC potential changes, occurred. It is suggested that these phenomena have a dendritic origin, and possible cellular mechanisms underlying the generation of paroxysmal events are discussed.     

Cobalt chloride induces neurite outgrowth in rat pheochromocytoma PC-12 cells through regulation of endothelin-2/vasoactive intestinal contractor

We investigated whether endothelin-2/vasoactive intestinal contractor (ET-2/VIC) gene expression, upregulated by hypoxia in cancer cells, was associated with differentiation in neuronal cells. RT-PCR analysis, morphological observations, and immunostaining revealed that CoCl2, a hypoxic mimetic agent, at 200 microM increased expression of the ET-2/VIC gene, decreased expression of the ET-1 gene, and induced neurite outgrowth in PC-12 rat pheochromocytoma cells. These effects induced by 200 microM CoCl2 were completely inhibited by the antioxidant N-acetyl cysteine at 20 mM. In addition, CoCl2 increased the level of intracellular reactive oxygen species (ROS) at an early stage. Furthermore, interleukin (IL)-6 gene expression was upregulated upon the differentiation induced by CoCl2. These results suggest that expression of ET-2/VIC and ET-1 mediated by ROS may be associated with neuronal differentiation through the regulation of IL-6. When the cells were treated with 500 microM CoCl2 for 24 hr, however, ET-2/VIC gene expression disappeared, IL-6 gene expression was downregulated, and necrosis was subsequently induced in the PC-12 cells.     

Cross-reactivity between nickel and palladium demonstrated by systemic administration of nickel

Concomitant patch test reactions to nickel and palladium have frequently been reported in patients undergoing investigation because of suspected allergic contact dermatitis. Theoretically, these reactions can be explained by multiple, concomitant, simultaneous sensitization as well as cross-sensitization. We studied whether concomitant reactions to nickel and palladium could represent cross-sensitization in females hypersensitive to combinations of nickel, palladium and cobalt. Females were patch tested with serial dilutions of nickel sulfate, cobalt chloride and palladium chloride on the upper back. 1 month later, when the patch test reactions were gone, the patients were randomized into 2 groups that were challenged orally with either nickel or placebo. 1 day later, the areas of previous positive patch test reactions were read in a blind way looking for flare-up reactions. Nickel provocation but not placebo yielded flare-up reactions on sites previously tested with nickel (P = 0.012) and palladium (P = 0.006), but were also observed on sites previously tested with cobalt, even though this was not statistically significant. Flare-up reactions of previous patch test reactions to nickel and palladium after oral challenge with nickel speak in favour of a cross-reactivity mechanism.