传染性蛋白因子——Prion

250年前英国的牧人注意到羊的一种致死性疾病,症状表现为兴奋-瘙痒-共济失调-全身瘫痪-死亡,其英语名称是Scrapie-瘙痒症.对于这种疾病的研究导致了目前尚有争议的Prion-传染性蛋白因子的发现,并引入了蛋白质具有复制能力的概念.尽管1966年就有人对上述疾病进行过研究,但真正的轰动效应是由于普罗赛纳(Prusiner)1982年发表在美国Science杂志上的一篇文章引起的.在这篇文章里普罗赛纳首次提出瘙痒症和CJD——人类的一种中枢神经系统退化病都是由一种不含DNA的蛋白颗粒引起的．

疯牛病与传染性蛋白因子

近几年在新闻媒介频频亮相的英国'疯牛病'(BSE),不仅在国际经贸磨擦中闹得沸沸扬扬,对其病因的研究在生物学界更是引起一场挑战,强烈地暗示着修改分子生物学'中心法则'的可能性。疯牛病属于'传染性海绵状脑病变'

Adenosine:An immune modulator of inflammatory bowel diseases

Inflammatory bowel disease(IBD)is a common and lifelong disabling gastrointestinal disease.Emerging treatments are being developed to target inflammatory cytokines which initiate and perpetuate the immune response.Adenosine is an important modulator of inflammation and its anti-inflammatory effects have been well established in humans as well as in animal models.High extracellular adenosine suppresses and resolves chronic inflammation in IBD models.High extracellular adenosine levels could be achieved by enhanced adenosine absorption and increased de novo synthesis.Increased adenosine concentration leads to activation of the A2a receptor on the cell surface of immune and epithelial cells that would be a potential therapeutic target for chronic intestinal inflammation. Adenosine is transported via concentrative nucleoside transporter and equilibrative nucleoside transporter transporters that are localized in apical and basolateral membranes of intestinal epithelial cells,respectively. Increased extracellular adenosine levels activate the A2a receptor,which would reduce cytokines responsible for chronic inflammation.

Sex-dimorphic adverse drug reactions to immune suppressive agents in inflammatory bowel disease

AIM:To analyze sex differences in adverse drug reactions(ADR) to the immune suppressive medication in inflammatory bowel disease(IBD) patients.METHODS:All IBD patients attending the IBD outpatient clinic of a referral hospital were identified through the electronic diagnosis registration system.The electronic medical records of IBD patients were reviewed and the files of those patients who have used immune suppressive therapy for IBD,i.e.,thiopurines,methotrexate,cyclosporine,tacrolimus and anti-tumor necrosis factor agents(anti-TNF);infliximab(IFX),adalimumab(ADA) and/or certolizumab,were further analyzed.The reported ADR to immune suppressive drugs were noted.The general definition of ADR used in clinical practice comprised the occurrence of the ADR in the temporal relationship with its disappearance upon discontinuation of the medication.Patients for whom the required information on drug use and ADR was not available in the electronic medical record and patients with only one registered contact and no further followup at the outpatient clinic were excluded.The difference in the incidence and type of ADR between male and female IBD patients were analyzed statistically by χ 2 test.RESULTS:In total,1009 IBD patients were identified in the electronic diagnosis registration system.Out of these 1009 patients,843 patients were eligible for further analysis.There were 386 males(46%),mean age 42 years(range:16-87 years) with a mean duration of the disease of 14 years(range:0-54 years);578 patients with Crohn's disease,244 with ulcerative colitis and 21 with unclassified colitis.Seventy percent(586 pts) of patients used any kind of immune suppressive agents at a certain point of the disease course,the majority of the patients(546 pts,65%) used thiopurines,176 pts(21%) methotrexate,46 pts(5%) cyclosporine and one patient tacrolimus.One third(240 pts,28%) of patients were treated with anti-TNF,the majority of patients(227 pts,27%) used IFX,99(12%) used ADA and five patients certolizumab.There were no differences between male and female patients in the use of immune suppressive agents.With regards to ADR,no differences between males and females were observed in the incidence of ADR to thiopurines,methotrexate and cyclosporine.Among 77 pts who developed ADR to one or more anti-TNF agents,significantly more females(54 pts,39% of all anti-TNF treated women) than males(23 pts,23% of all antiTNF treated men) experienced ADR to an anti-TNF agent [P = 0.011;odds ratio(OR) 2.2,95%CI 1.2-3.8].The most frequent ADR to both anti-TNF agents,IFX and ADA,were allergic reactions(15% of all IFX users and 7% of all patients treated with ADA) and for both agents a significantly higher rate of allergic reactions in females compared with males was observed.As a result of ADR,36 patients(15% of all patients using anti-TNF) stopped the treatment,with significantly higher stopping rate among females(27 females,19% vs 9 males,9%,P = 0.024).CONCLUSION:Treatment with anti-TNF antibodies is accompanied by sexual dimorphic profile of ADR with female patients being more at risk for allergic reactions and subsequent discontinuation of the treatment.

HearNPV Pseudotyped with PIF1,2,and 3 from MabrNPV：Infectivity and Complex Stability

Effective oral infection is set off by interaction of a group of conserved per os infectivity factors(PIFs) with larval midgut columnar epithelial cells. We constructed pseudotyped viruses by substituting pif1, pif2 or pif3 genes of Helicoverpa armigera nucleopolyhedrovirus(Hear NPV) with their homologs from Mamestra bracissae multiple nucleopolyhedrovirus and tested their infectivity to tissue culture cells and to larvae. Transfection and infection assays revealed that all recombinant viruses generated infectious budded virus in both cell culture and in larvae. Electron microscopy showed synthesized occlusion body and occlusion derived virus(ODV) were morphologically indistinguishable from those of the parental virus. By contrast, feeding assays revealed that pseudotyped viruses could not rescue oral infectivity except for pif3 pseudotyped virus that only partially rescued oral infectivity but at a mortality rate much lower than that of the parental Hear NPV. Consistent with the bioassay result, PIF complex was detected in ODVs of pif3 pseudotyped virus only but not in pif1 or pif2 pseudotyped viruses. Our results suggest that PIF complex is essential for oral infectivity, and in the formation of the PIF complex, PIF1, 2 are virus-specific while PIF3 does not appear to be as specific and can function in heterologous environment, albeit to a much more limited extent.