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101.
Indoleamine 2,3-dioxygenase (IDO), a flavin-dependent enzyme that catalyzes the conversion of tryptophan to kynurenine, is induced in peripheral blood mononuclear cells by interferon-gamma (IFN gamma). Interleukin-4 (IL-4) is a cytokine that modulates the functional properties of monocytes/macrophages, and we investigated the effects of IL-4 on IDO. We showed that IL-4 inhibited the induction of IDO mRNA and IDO activity by IFN gamma in human monocytes. The inhibitory effect was evident with as little as 2 U/mL of IL-4. These results provide the first evidence that a cytokine can provide a negative signal for IDO expression and that IL-4 can influence the catabolism of tryptophan. 相似文献
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Scintigraphy in 3 patients with chondroblastoma showed that the tumors were hyperemic and avidly accumulated the radionuclide. These changes were also present in adjacent normal bone, but to a lesser degree. This suggest that radionuclide uptake in chondroblastoma is a function of the blood supply to the tumor rather than primary matrix extraction. 相似文献
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Myocardial metabolism in cyanotic congenital heart disease 总被引:1,自引:0,他引:1
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The authors report a case of a hepatic artery aneurysm that simulated a mass in the head of the pancreas. The correct diagnosis was made preoperatively based on several findings: curvilinear calcification within the mass on CT, a well-defined cystic collection on ultrasound, absence of biliary duct dilatation or jaundice, and presence of other aneurysms. 相似文献
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Xu F Ng VY Kroetz DL de Montellano PR 《The Journal of pharmacology and experimental therapeutics》2006,318(2):835-839
The saturated C20 isoprenoid phytanic acid is physiologically derived from phytol released in the degradation of chlorophyll. The presence of a C-3 methyl group in this substrate blocks normal beta-oxidation, so phytanic acid degradation primarily occurs by initial peroxisomal alpha-oxidation to shift the register of the methyl group. However, individuals with Refsum's disease are genetically deficient in the required phytanoyl-CoA alpha-hydroxylase and suffer from neurological pathologies caused by the accumulation of phytanic acid. Recent work has shown that phytanic acid can also be catabolized by a pathway initiated by omega-hydroxylation of the hydrocarbon chain, followed by oxidation of the alcohol to the acid and conventional beta-oxidation. However, the enzymes responsible for the omega-hydroxylation of phytanic acid have not been identified. In this study, we have determined the activities of all of the rat and human CYP4A enzymes and two of the rat CYP4F enzymes, with respect to the omega-hydroxylation of phytanic acid. Furthermore, we have shown that the ability to omega-hydroxylate phytanic acid is elevated in microsomes from rats pretreated with clofibrate. The results support a possible role for CYP4 enzyme elevation in the elimination of phytanic acid in Refsum's disease patients. 相似文献