Envelope glycoprotein gp120 of human immunodeficiency virus type 1 alters ion transport in astrocytes: implications for AIDS dementia complex

Infection by human immunodeficiency virus type 1 (HIV-1) is often complicated by a variety of neurological abnormalities. The most common clinical syndrome, termed acquired immunodeficiency syndrome (AIDS) dementia complex, presents as a subcortical dementia with cognitive, motor, and behavioral disturbances and is unique to HIV-1 infection. The pathogenesis of this syndrome is poorly understood but is believed to involve interactions among virally infected macrophages/microglia, astrocytes, and neurons. In this study, we show that exposure of primary rat and human astrocytes to heat-activated HIV-1 virions, or to eukaryotically expressed HIV-1 and HIV-2 envelope glycoproteins (gp120) stimulates amiloride-sensitive Na+/H+ antiport, potassium conductance, and glutamate efflux. These effects are blocked specifically by amiloride, an inhibitor of Na+/H+ antiport and by the selective removal of gp120 with immobilized monoclonal antibody. As a result of modulation of astrocytic function by gp120, the ensuing neuronal depolarization and glutamate exposure could activate both voltage-gated and N-methyl-D-aspartate-regulated Ca2+ channels, leading to increases in intraneuronal Ca2+ and neuronal death. These findings implicate the astrocyte directly in the pathogenesis of AIDS dementia complex.     

Streptococcus bovis bacteremia: unusual complications

Streptococcus bovis bacteremia is known to be related to neoplastic lesions of the colon. We describe a patient with several complications of S bovis bacteremia and adenocarcinoma of the colon--endocarditis, spondylodiskitis, and splenic abscess. We believe this is the eighth known case of endocarditis and diskitis caused by S bovis and the third case of endocarditis and splenic abscess by S bovis in a patient with adenocarcinoma of the colon.     

Hydroxychloroquine reverses thrombogenic properties of antiphospholipid antibodies in mice

BACKGROUND: Previous studies have demonstrated that human monoclonal and polyclonal anticardiolipin antibodies have thrombogenic properties in vivo. Using such a model in which these antibodies have been shown to increase both the size of an induced thrombus and the duration of time in which such a clot lasts, we investigated whether hydroxychloroquine alters the dynamics of such thrombus formation. METHODS AND RESULTS: Three groups of nine mice were injected with purified immunoglobulin G (IgG) from a patient with the antiphospholipid syndrome (IgG-APS) and then fed with hydroxychloroquine at various doses (100, 6, and 3 mg/kg body wt). Three control groups of mice were also studied, including mice injected with IgG-APS and then fed with placebo, as well as two other groups injected with IgG from normal human serum and fed either hydroxychloroquine or placebo. A standardized thrombogenic injury was subsequently induced in the femoral vein of each mouse and the area (size) of thrombus measured as well as the total period of time that thrombus was present. Mice treated with hydroxychloroquine and IgG-APS showed significantly smaller thrombi that persisted for a shorter period of time compared with animals treated with IgG-APS and placebo. CONCLUSIONS: Hydroxychloroquine significantly diminished both thrombus size and total time of thrombus formation in mice previously injected with IgG-APS.     

Aminopeptidases in cells of non-Hodgkin's lymphoma of varying degrees of malignancy and in lymphogranulomatosis

26 cases of lymphoproliferative diseases were studied: 8 cases of reactive follicular hyperplasia (RFH), 11 cases of non-Hodgkin's malignant lymphomas (NML), 7 cases of lymphogranulomatosis (LGM). Only gamma-glutamyl transpeptidase (GGT) was found in lymphoid cells of B- and T-dependent areas of lymph nodes with reactive changes as well as in tumor cells of NML and LGM. GGT activity was more pronounced in NML of high-grade malignancy (centroblast and immunoblast) as compared to lymphomas of lower grade of malignancy (lymphocytic, centroblast-centrocytic and in Lennert lymphoma). GGT activity in cells of Hodgkin and Berezovsky-Sterberg in some cases of LGM was high, in others low. Significant differences in GGT activity between RFH and follicular centroblast-centrocytic lymphoma were not found. Activity of aminopeptidase M was observed in histiocytes, fibroblasts, vessels and areas of connective tissue growth. Aminopeptidase A activity was observed in vessels only. Activity of dipeptidyl(amino)peptidase IV was observed in some lymphoid cells in RFH, NML and LGM. Thus, GGT activity may be considered as a differential-diagnostic marker in separating NML of high and low degree of malignancy and this may presume a different sensitivity to the therapy.     

Validation of an inhibition ELISA using a monoclonal antibody for foot-and-mouth disease (FMD) primary diagnosis

An inhibition ELISA (IH-ELISA) test for foot-and-mouth disease virus (FMDV) was validated using 106 epithelial samples from suspected cases of FMD in Argentina submitted to the Argentine National Diagnostics Laboratory (GELAB) over a period of 12 months and examined in parallel with the complement fixation test (CFT). IH-ELISA was found to be more sensitive, detecting 25% (26 samples) more FMDV positives than the CFT in original suspensions of field samples. The effect of storage conditions on 12S stability was examined. Plates stored at 4 degrees C blocked with 1% ovalbumin and plates stored at -20 degrees C with or without blocking buffer could be used for at least 90 days. When various brands of polystyrene plates were compared for 12ps adsorption it was found that those microplates of higher binding capacity were more efficient.     

Congenital chylothorax in siblings

We describe two cases of congenital chylothorax in siblings with important differences from previously described familial cases. Our findings support the likelihood of an autosomal recessive inheritance in some cases of this condition, rather than X-linked recessive inheritance, which has also been suggested. Autopsy findings from one of these cases and others previously described suggest that the pathophysiological mechanisms involved may be variable.     

近20年塔里木河干流生态环境变化遥感监测分析

针对塔里木河流域综合治理后生态环境的变化状况及植被的恢复状况等热点问题,基于遥感时空变化分析方法从土地利用、地表水体和植被覆盖度的时空变化方面分析了近20年来塔里木河干流生态环境的变化状况。结果表明:(1)塔里木河干流土地利用受到人类活动的影响显著,自2000年以来,塔里木河干流耕地面积增加显著,净增2 229 km~2,草地面积整体下降,萎缩3 157 km~2;(2)综合治理以来,下游河段2009—2018时段水体出现频率明显高于2000—2008时段,水体出现频率提高约15%;(3)2000年以来,塔里木河流域的植被覆盖度持续增加,特别是下游河段植被覆盖度增加明显,覆盖度增加18%。但中、上游流域的植被覆盖度的增加趋势主要贡献来源于耕地,中上游地区耕地的增加仍会对塔里木河流域的生态保护和恢复造成一定的影响。     

含三维内裂纹透明类岩石材料破坏红外热像试验研究

由于目前针对含三维内裂纹的岩石破坏红外热像特征的研究较少,本文基于预埋浇注法制作含内裂纹类岩石试件,开展了单轴压缩块体试验和巴西圆盘劈拉试验,得到含内裂纹的岩石破坏过程,监测内裂纹扩展及试件破坏过程中的红外热像特征,得到以下结论:(1)含三维内裂纹的块体试件在单轴压缩下,在预制内裂纹面上发生剪切破坏;(2)块体试件在单轴压缩作用下红外热像特征明显,在破坏时,在预制内裂纹面处急剧升温;(3)含三维内裂纹巴西圆盘试件在预制内裂纹尖端发生翼型裂纹扩展,边缘带有针刺状Ⅲ型裂纹参与特征,最终翼型裂纹与上下表面贯穿;(4)巴西圆盘试验的红外热像特征与块体单轴压缩不同,在断裂面处未发生明显变化。研究结果为研究三维内裂纹的扩展规律及内裂纹扩展破裂的红外热像规律可提供一定的试验参考。