Rheumatoid peripheral blood phagocytes are primed for activation but have impaired Fc-mediated generation of reactive oxygen species

Significant levels of circulating immune complexes (ICs) containing rheumatoid factors and immunoglobulin G in peripheral blood are a characteristic feature of rheumatoid arthritis (RA). ICs interact through Fcγ receptors (FcγR) to activate phagocytes in numerous inflammatory processes. The high concentration of neutrophils in synovial fluid during active phases of the disease, together with their destructive capacity, pose important questions as to their role in the pathogenesis of RA. Functional defects in RA or control peripheral blood neutrophil FcγRs were examined with a specific FcγR-mediated reactive oxygen species (ROS) assay. Heterologous cross-linking of FcγRIIa and FcγRIIIb on neutrophils resulted in a significantly decreased production of ROS by RA cells compared with controls matched for age and sex. However, expression and homologous ligation of receptors did not differ between these groups. These data suggest that neutrophil priming does occur before emigration into the joint and that blood neutrophils from patients with RA have a functional impairment in cooperative FcγR-mediated ROS generation. This may account for the increased susceptibility to bacterial infection that arises in patients with severe disease.     

降解烤烟秸秆和烟碱菌株的筛选及其产酶特性

摘要:【目的】为获得能够降解烤烟秸秆和烟碱的菌株,并探索其降解烤烟秸秆的利用途径。【方法】以烤烟秸秆为唯一碳氮源,从烟田土壤中进行了菌株的筛选。采用形态学观察、生理生化特性鉴定、16S rRNA基因序列鉴定等方法对该菌株进行了鉴定,并对其以烤烟秸秆为底物进行液态发酵的产酶活性和木质纤维素降解效果进行了测定。【结果】结果表明:该菌株为巨大芽孢杆菌(Bacillus megaterium)。在以烤烟秸秆为主要营养物质液态发酵条件下该菌株具有较强的木质素降解能力,最大漆酶活力达到418.52 U/L,而木质素过氧化物酶和锰过氧化物酶的最大酶活分别为19.71 U/L 和64.71 U/L。此外,发酵20 d后该菌能够完全降解发酵液中的烟碱。【结论】本研究筛选到了1株能够较好降解烤烟秸秆和完全降解烟碱的巨大芽孢杆菌(Bacillus megaterium),且该菌株具有利用烤烟秸秆生产漆酶的应用价值。     

Phenothiazine antagonism of the noradrenergic inhibition of cerebellar purkinje neurons

Phenothiazine derivatives were examined as potential antagonists of the inhibitory noradrenergic synapses from the nucleus locus coeruleus to rat cerebellar Purkinje cells. Fluphenazine, and its thioxanthine analogue, flupenthixol, antagonized the inhibitory action of norepinephrine, when iontrophoretically applied to single cells. Alpha-flupenthixol was generally more active than the beta isomer. Fluphenazine had no appreciable effect on inhibitions induced by iontophoresis of GABA or cyclic AMP. Parenteral fluphenazine also blocked the inhibition of Purkinje cells produced by the stimulation of the noradrenergic pathway from locus coeruleus, but basket and stellate cell inhibitory inputs to Purkinje cells were unaffected. These data suggest that fluphenazine can specifically block a known central adrenergic inhibitory pathway.