Oxidation of LDL may contribute to atherogenesis, though the nature of the in vivo oxidant(s) remains obscure. Myeloperoxidase, the enzyme responsible for hypochlorous acid/hypochlorite (HOCl) production in vivo, is present in active form in human atherosclerotic lesions, and HOCl aggregates and transforms LDL into a high-uptake form for macrophages in vitro. Here we demonstrate HOCl-modified proteins in human lesions using an mAb raised against HOCl-modified LDL that recognizes HOCl-oxidized proteins but does not cross-react with Cu

Alzheimer type II astrocytosis is the pathological hallmark of hepatic encephalopathy. These astrocytes undergo a characteristic morphological change and, in addition, lose immunoreactivity for glial fibrillary acidic protein (GFAP). However, a previous study in the portacaval shunted rat, a model of hepatic encephalopathy, revealed increased rather than decreased GFAP immunoreactivity in Bergmann glia, a specialized group of cerebellar astrocytes. In the present study, sections of cerebellar vermis from 15 cirrhotic patients with hepatic encephalopathy and varying degrees of Alzheimer type II astrocytosis were stained using antisera to GFAP. The Bergmann glial cells did not show altered GFAP immunoreactivity compared to controls. In addition, the degree of GFAP immunoreactivity was not correlated with the degree of Alzheimer type II change nor related to the aetiology of the liver disease. These results suggest a differential response of Bergmann glia in human hepatic encephalopathy.

This study evaluated current methods for demonstrating and categorizing cortical plaques, with the aim of establishing objective methodology for future diagnostic evaluation. Analysis of four methods of tissue processing revealed that the highest numbers of plaques were identified in formalin-fixed, paraffin-embedded tissue regardless of the stain used. Analysis of three silver stains and four immunohistochemical dilutions of an antibody to beta A4 protein revealed that the recent silver method published by Garvey et al. [(1990) J Histotechnol 14: 39-42] was equivalent to beta A4 immunohistochemistry in demonstrating the highest number of plaques. Plaque differentiation was easier and more reliable in silver compared to beta A4-stained sections, although the number of identifiable small compact plaques was significantly reduced in silver-stained sections. These studies show that plaque differentiation may be compromised by tissue processing and staining protocols. The establishment of superior methods may provide better diagnostic resolution for patients with Alzheimer's disease.

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