模拟高原低氧环境对兔龈下菌斑影响的实验研究

目的:探讨高原低氧环境对兔龈下菌斑中定植的细菌种类、数量和内毒素水平的影响。方法:40只雄性大白兔随机分为平原对照组、平原实验组、高原对照组和高原实验组,每组10只,两实验组采用正畸丝结扎下颌中切牙并联合牙周炎食谱饲养的方法建立牙周炎模型,同时,两高原组送入低压氧舱(模拟海拔高度5 000m,23 h/d)内饲养。8周后检测牙周探诊深度(PD),附着丧失(AL)、菌斑指数(PLI)、牙龈指数(GI),pH试纸检测龈沟液pH值,采集龈下菌斑进行厌氧菌分离、培养、计数、镜检、内毒素检测。结果:高原实验组AL、PLI、GI等临床牙周指标以及龈沟液pH值、活菌数、内毒素水平等均明显高于其他各组(P<0.05),且细菌种类更为丰富;相关分析显示,龈沟液pH值、活菌数与AL、PLI、GI呈正相关,内毒素水平与AL呈正相关。结论:高原低压低氧的特殊环境更利于G-厌氧菌的定居,使牙周袋内氧气消耗量增加,pH值升高。     

肺鼠疫的临床、病理及胸部X线影像特征

鼠疫是危害人类最严重的烈性传染病,肺鼠疫是其中最致命的类型。本文就肺鼠疫的发病机制以及临床、病理及X线平片表现进行总结,以期临床对其提高警惕,从而早期正确诊断,挽救肺鼠疫患者的生命,降低死亡率。     

抗噬菌体鼠疫菌株的发现与研究

在天山山地灰旱獭鼠疫自然疫源地中,从病的灰旱獭体内分离出抗鼠疫噬菌体株。该菌株形态呈多形性,菌落不典型,对动物的毒力弱并失去抗源性;但经传代或冷冻干燥保存一段时间后,逐渐失去对鼠疫噬菌体的抗性,与此同时菌落形态转为R型,具有抗原性,对动物的毒力也随之增强。     

乌鲁木齐市米东区2007-2009年鼠疫监测结果分析

目的通过对乌鲁木齐市米东区所辖的戈壁荒漠地带鼠疫流行情况进行调查,为制定我市鼠疫防治措施提供科学的依据。方法 2007-2009年在米东区所辖的戈壁荒漠地带采用鼠疫流行病学、生态学、动物昆虫学、血清学、病原学等方法进行鼠疫疫源调查。结果①共捕获各种鼠类586只,集蚤6 432匹。②2008-2009年共分离F1抗体阳性血清36份。③2009年分离鼠疫菌2株。结论鼠疫菌的分离与F1抗体阳性血清说明乌鲁木齐市米东区所辖的戈壁荒漠地带存在鼠疫自然疫源地并有动物间鼠疫流行。为了防止人间鼠疫流行,应加强鼠防意识,加大鼠防投入力度,全面开展各项鼠疫防治监测工作。     

Cynomolgus macaque model for pneumonic plague

A recombinant vaccine (rF1V) is currently being developed for protection against pneumonic plague. An essential component in evaluating efficacy of the rF1V vaccine is the development of a well-understood animal model that shows similarity to human disease. The objective of this study was to determine the inhaled median lethal dose (LD₅₀), evaluate the pathophysiology of disease and identify appropriate study endpoints in a cynomolgus macaque (CM) model of pneumonic plague. Eighteen CMs were challenged by head-only aerosol exposure with seven dosages of Yersinia pestis CO92. An LD₅₀ of 24 colony forming units was estimated using Probit analysis. Disease pathology was evaluated by blood culture, clinical pathology, histopathology and telemetry. CMs that died became febrile following challenge and died 34–92 h after onset of fever. Bacteremia, increased respiration and heart rate, decreased blood pressure and loss of diurnal rhythm were also observed in conjunction with onset of fever. Histopathological examinations revealed significant findings in the lungs (intra-alveolar neutrophils and fibrinous pleuritis) consistent with pneumonic plague. These data indicate that the disease pathology observed in CMs following aerosol exposure to Y. pestis CO92 is similar to that of pneumonic plague in humans. Thus, the CM is an appropriate model to evaluate efficacy of a recombinant F1V vaccine candidate.     

阿拉善荒漠区鼠疫自然疫源性存在的可能性

目的探讨阿拉善荒漠鼠疫自然疫源性存在的可能性。方法对捕获的宿主动物采用细菌学和血清学方法进行检验。结果血清学检验68只大沙鼠血清,均为阴性。细菌学检验各种宿主动物802只,均为阴性。结论根据宿主动物的分布及其周边地区情况,阿拉善荒漠仍然有存在鼠疫自然疫源性的可能性。     

Conserved amino acids W423 and N424 in receptor-binding domain of SARS-CoV are potential targets for therapeutic monoclonal antibody

The receptor-binding domain (RBD) on spike protein of severe acute respiratory syndrome-associated coronavirus (SARS-CoV) is the main region interacting with the viral receptor-ACE2 and is a useful target for induction of neutralizing antibodies against SARS-CoV infection. Here we generated two monoclonal antibodies (mAbs), targeting RBD, with marked virus neutralizing activity. The mAbs recognize a new conformational epitope which consists of several discontinuous peptides (aa. 343-367, 373-390 and 411-428) and is spatially located neighboring the receptor-binding motif (RPM) region of the RBD. Importantly, W423 and N424 residues are essential for mAb recognition and are highly conserved among 107 different strains of SARS, indicating that the residues are the most critical in the epitope which is a novel potential target for therapeutic mAbs. A human-mouse chimeric antibody, based upon the original murine mAb, was also constructed and shown to possess good neutralizing activity and high affinity.     

Wild Felids as Hosts for Human Plague, Western United States

Plague seroprevalence was estimated in populations of pumas and bobcats in the western United States. High levels of exposure in plague-endemic regions indicate the need to consider the ecology and pathobiology of plague in nondomestic felid hosts to better understand the role of these species in disease persistence and transmission.     

Further development of raccoon poxvirus-vectored vaccines against plague (Yersinia pestis)

In previous studies, we demonstrated protection against plague in mice and prairie dogs using a raccoon pox (RCN) virus-vectored vaccine that expressed the F1 capsular antigen of Yersinia pestis. In order to improve vaccine efficacy, we have now constructed additional RCN-plague vaccines containing two different forms of the lcrV (V) gene, including full-length (Vfull) and a truncated form (V307). Mouse challenge studies with Y. pestis strain CO92 showed that vaccination with a combination of RCN-F1 and the truncated V construct (RCN-V307) provided the greatest improvement (P = 0.01) in protection against plague over vaccination with RCN-F1 alone. This effect was mediated primarily by anti-F1 and anti-V antibodies and both contributed independently to increased survival of vaccinated mice.