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排序方式: 共有158条查询结果,搜索用时 46 毫秒
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Antioxidant status of Fanconi anemia fibroblasts 总被引:5,自引:1,他引:4
Summary Several observations in the recent literature have indicated that Fanconi anemia (FA) cells may be primarily deficient in the detoxification of activated oxygen species. To evaluate the antioxidant status of FA fibroblasts, we measured Mn-containing superoxide dismutase (Mn-SOD), CuZn-containing superoxide dismutase (CuZn-SOD), catalase, and glutathione peroxidase activities, as well as cellular glutathione contents and total nonenzymatic antioxidant potential in Fa and control fibroblasts at multiple time point during a single passage. All parameters exhibited a characteristic pattern of changes during a period of 19 days following trypsinization. Unlike FA erythrocytes, which are known to be deficient in CuZn-SOD, FA fibroblasts exhibited normal CuZn-SOD activities. Also, the nonenzymatic antioxidant potential as well as glutathione levels were similar in FA and control fibroblasts. However, Mn-SOD, catalase, and glutathione peroxidase activities were consistently higher in FA fibroblasts. We hypothesize that the elevation of these enzyme activities might reflect a cellular prooxidant state in FA resulting from an increased formation of endogenous oxidizing molecular species that trigger enhanced synthesis of certain enzymatic antioxidant defenses. 相似文献
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Mental training affects distribution of limited brain resources 总被引:1,自引:0,他引:1
Slagter HA Lutz A Greischar LL Francis AD Nieuwenhuis S Davis JM Davidson RJ 《PLoS biology》2007,5(6):e138
The information processing capacity of the human mind is limited, as is evidenced by the so-called “attentional-blink” deficit: When two targets (T1 and T2) embedded in a rapid stream of events are presented in close temporal proximity, the second target is often not seen. This deficit is believed to result from competition between the two targets for limited attentional resources. Here we show, using performance in an attentional-blink task and scalp-recorded brain potentials, that meditation, or mental training, affects the distribution of limited brain resources. Three months of intensive mental training resulted in a smaller attentional blink and reduced brain-resource allocation to the first target, as reflected by a smaller T1-elicited P3b, a brain-potential index of resource allocation. Furthermore, those individuals that showed the largest decrease in brain-resource allocation to T1 generally showed the greatest reduction in attentional-blink size. These observations provide novel support for the view that the ability to accurately identify T2 depends upon the efficient deployment of resources to T1. The results also demonstrate that mental training can result in increased control over the distribution of limited brain resources. Our study supports the idea that plasticity in brain and mental function exists throughout life and illustrates the usefulness of systematic mental training in the study of the human mind. 相似文献
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Sperandio D Tai VW Lohman J Hirschbein B Mendonca R Lee CS Spencer JR Janc J Nguyen M Beltman J Sprengeler P Scheerens H Lin T Liu L Gadre A Kellogg A Green MJ McGrath ME 《Bioorganic & medicinal chemistry letters》2006,16(15):4085-4089
The synthesis of novel [1,2,4]oxadiazoles and their structure-activity relationship (SAR) for the inhibition of tryptase and related serine proteases is presented. Elaboration of the P'-side afforded potent, selective, and orally bioavailable tryptase inhibitors. 相似文献
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Georges F Vles Johan S Vles Maarten van Kleef Jan van Zundert Heleen M Staal Wim E Weber Lodewijk W van Rhijn Dan Soudant H Kerr Graham Anton J de Louw 《BMC neurology》2010,10(1):52
Background
Cerebral palsy (CP) may cause severe spasticity, requiring neurosurgical procedures. The most common neurosurgical procedures are continuous infusion of intrathecal baclofen and selective dorsal rhizotomy. Both are invasive and complex procedures. We hypothesized that a percutaneous radiofrequency lesion of the dorsal root ganglion (RF-DRG) could be a simple and safe alternative treatment. We undertook a pilot study to test this hypothesis. 相似文献39.
Wilma M Frederiks Heleen Vreeling-Sindelárová Cornelis J F Van Noorden 《The journal of histochemistry and cytochemistry》2007,55(2):175-181
Oxygen insensitivity of carcinoma cells and oxygen sensitivity of non-cancer cells in the histochemical assay of glucose-6-phosphate dehydrogenase (G6PD) enables detection of carcinoma cells in unfixed cell smears or cryostat sections of biopsies. The metabolic background of oxygen insensitivity is still not understood completely. In the present study, rat hepatocytes, rat hepatoma cells (FTO-2B), and human colon carcinoma cells (HT29) were used to elucidate these backgrounds. The residual activity in oxygen was 0%, 55%, and 80% in hepatocytes, hepatoma cells, and colon carcinoma cells, respectively. N-ethylmaleimide (NEM), a blocker of SH-groups, did not affect G6PD activity in both carcinoma cell types but reduced G6PD activity in hepatocytes by 40%. Ultrastructural localization of G6PD activity was exclusively in the cytoplasm of carcinoma cells, but in hepatocytes both in cytoplasm and peroxisomes. NEM abolished peroxisomal G6PD activity only. Histochemical assay of catalase activity demonstrated absence of peroxisomes in both carcinoma cell lines. It is concluded that absence of SH-sensitive G6PD activity in peroxisomes in cancer cells is responsible for the oxygen-insensitivity phenomenon. 相似文献
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