狂犬病毒在慢性感染细胞培养中对宿主细胞的影响

<正> 本文报告二个细胞系(BHK-21/13S和HeP-2)对狂犬病毒慢性感染过程长期观察的结果。 狂犬病毒在二种细胞中慢性感染过程的观察,结果表明BHK-21/135狂犬病毒的特征是细胞含有病毒抗原水平呈周期性地幅度很大的波动(从100％到<1％)并且表明当抗原阳性细胞较多时细胞单层稀薄,在抗原阳性细胞较少的情况下,可见到在稠密的细胞单层上有局灶性或单个的含有病毒抗原的细胞。狂犬病毒慢性感染滴度较低,不超过3-4lgLD_(50)/0.03ml。 早期文献曾已阐明狂犬病毒的感染滴度与含萤光抗原或特异性包涵体的细胞数量有平行关系。作者是从30代以后的细胞开始进行有系统的观察,而上述文献所提供的是25     

两种传代细胞系对轮状病毒D36株(P[4]G2)敏感性的比较

目的探讨轮状病毒D36株在MDCK细胞和Vero细胞上培养的适应性,确定其培养的最佳细胞基质及培养条件。方法将D36株以MOI 1.0按不同培养瓶分组接种MDCK细胞和Vero细胞,补充含有不同浓度胰酶的维持液,于不同时间观察两种细胞病变的情况,同时抽样检测病毒滴度,分析两种细胞对D36株的敏感性。结果D36株病毒感染MDCK细胞后第6天病毒滴度达到最高,为(5.00～5.50)lgCCID50/mL;而D36株病毒感染Vero细胞后病毒滴度于第8天达高峰,为(4.50～4.75)lgCCID50/mL。另外,在两种细胞维持液中加入约0.8μg/mL的胰酶均可提高病毒滴度。结论两种细胞系在同等条件下感染D36株病毒后,MDCK细胞比Vero细胞出现病变的时间早,每一批MDCK细胞培养物病毒滴度高于同批次试验的Vero细胞培养物。     

脑啡肽-干扰素α-m融合蛋白外用治疗单纯疱疹病毒感染

为探讨脑啡肽-干扰素α-m融合蛋白(EI)外用治疗单纯疱疹病毒感染的作用,分别用HSV-1感染兔子角膜、HSV-2感染豚鼠阴道建立动物感染模型.兔子角膜感染24h后用融合蛋白滴眼液治疗,每天3次,每次0.5ml,共14天.豚鼠阴道感染48h后,用融合蛋白涂剂抹外阴病灶,每天3次,每次10mg,共14天.用IFNα-m和生理盐水/赋形剂作为对照.采用记录病损程度分级法进行临床症消减观察,并于治疗前后测定实验动物病灶病毒滴度、HSV抗体滴度及NK细胞活性.结果显示:与IFNα-m相比,EI治疗组实验动物病毒感染症状大幅减轻且病程缩短,动物病灶中病毒滴度下降,抗HSV抗体滴度升高,NK细胞活性增强.说明脑啡肽干扰素融合蛋白具有较强的消除炎症和局部抗病毒作用,可用于治疗HSV感染引起的疾病.     

L—A—1株甲肝病毒细胞外释动态及回收利用方法的建立

用现行生产用L－A-1株甲肝病毒进行了系列细胞外释动态试验，结果表明，病毒感染细胞后1～5周，病毒持续释放，平均两度为5．46logTCID50/ml。上清液经超滤浓缩，平均滴度达7．19logTCID50/ml略高于细胞抽提物病毒滴度（7．01logTCID50/ml）。     

用15L转瓶大规模生产腮腺炎疫苗的研究

细胞与病毒同时接种于33℃培养5天,其病毒滴度平均为6.25 LogCCID50/ml,但细胞成片后再感染,其病毒滴度平均为4.85 LogCCID50/ml.在鸡胚细胞感染2.3×10-3病毒剂量时,滴度可达≥6.5 LogCCID50/ml,病毒高峰期于100小时和120小时分二次收获,其滴度分别达到6.0和≥6.5 LogCCID50/ml.每瓶产疫苗量4500ml和9000ml,病毒滴度没有影响.液体疫苗于2～8℃保存14天,滴度由5.75降至4.75 LogCCID50/ml,而将疫苗保存在-18℃至18周,其滴度由6.38缓慢下降至5.0 logCCID50/ml.     

HSV体外感染对IgG产生的抑制作用和TNF及r-IFN对它的影响

本文观察了体外HSV-I感染对人淋巴细胞增殖、分化,产生免疫球蛋白的影响。HSV-I能感染PWM刺激的人扁桃体淋巴细胞,并抑制其增殖和免疫球蛋白(IgG)的产生,感染实验组的IgG产量较对照组明显降低(P<0.005)。HSV-I感染后,上清中可检出一定量的病毒,其滴度为10~(3·2)—10~(5·7)TCID50/ml;直接免疫荧光法检出病毒抗原阳性细胞为3％—8.5％。在感染实验系统中加入重组的IFN_a(r-IFN_a)、IFN_γ(r-IFN_γ)和纯化的肿瘤坏死因子(TNF),观察到r-IFN。和TNF均有一定程度抗病毒作用,部分解除HSV-I对IgG产生的抑制作用。和对照组相比,差异显著(P<0.01)。r-IFN_γ对HSV-I的感染和IgG产生几乎无作用(P>0.05),但r-IFN_γ对TNF有协同作用:抑制病毒增殖和解除HSV-I对IgG产生的抑制,比单独用TNF组更为显著(P<0.01)。     

人巨细胞病毒在包皮细胞培养中的潜伏性感染

用具有特异性抑制蛋白质糖基化作用的含氨基葡糖的衣霉素Tunicamycin(TM)处理人胚包皮细胞(HEF)建立起人巨细胞病毒(HCMV)的潜伏性感染模型。观察了TM对HEF细胞及HCMV的毒性作用,当TM浓度大于500ng/ml时对单层细胞生长有影响;在TM浓度为500ng/ml时,细胞生长虽受一定程度的影响,但仍然逐步生长扩增;不同浓度的TM对HCMV有不同程度的影响,但不能将全部HCMV在短期内完全抑制,在TM含量1000ng/ml的维持液中处理5日的HCMV感染细胞培养物中未检出感染性病毒。感染HCMV的HEF单层细胞保持在含TM500ng/ml的维持液中于37℃培养7日,然后换加不含TM的维持液并改置40.5℃中培养,可保持HCMV以非感染性的病毒状态潜伏于HEF细胞内长达135日;在此潜伏期间如将细胞培养物由40.5℃再移置37℃中培养,HCMV能被激活为可检测到高滴度的感染性病毒。定期取在40.5℃中培养的HCMV潜伏感染细胞培养物进行感染中心测定(Infections Center Assays),感染中心滴度(Infectous Center Titer)为0.0004％～0.005％,只有很低的病毒重激活率。对潜伏性感染及TM引起疱疹病毒的潜伏性机理结合文献作了简要讨论。     

一株产生EB病毒的狨猴淋巴细胞株的建立

用Ｂ９５８细胞株产生的ＥＢ病毒,转化棉顶狨猴外周血淋巴细胞,获得ＫＭＴ３细胞株。该细胞株能产生高滴度的ＥＢ病毒。含ＥＢ病毒衣壳抗原的自然阳性细胞率为３～５％,激活后达５０～６０％,其培养上清液可直接转化人淋巴细胞得到传代细胞系。ＫＭＴ３细胞染色体数２ｎ＝４６条     

EV71病毒对树鼩原代肾上皮细胞感染模型的建立

目的建立EV71对树鼩原代肾细胞的感染模型。方法胰蛋白酶消化法获得树鼩的原代肾细胞,用EV71感染树鼩肾细胞,测定1、2、4、6和8 d培养上清病毒滴度,分别用Western blot和间接免疫荧光法检测细胞中EV71病毒VP1蛋白的表达,以确定EV71病毒对树鼩原代肾细胞的感染性。结果对分离得到的树鼩原代肾细胞进行传代纯化和形态鉴别,建立以树鼩原代肾细胞为主的细胞培养。用EV71病毒感染树鼩原代肾细胞,感染后48~96 h病毒滴度可达到1.3×10~6TCID_(50)/m L,说明EV71病毒可有效感染树鼩原代肾细胞并有效增殖。Western blot检测发现,EV71病毒VP1蛋白可在感染后2~8 d的树鼩原代肾细胞中有效检出,间接免疫荧光法则在感染后2~6 d细胞的细胞质中检测到病毒VP1蛋白的分布。结论在成功建立树鼩原代肾细胞培养的基础上,确定了EV71病毒对树鼩原代肾细胞的感染性和病毒增殖特性,初步建立了EV71树鼩原代肾细胞感染模型。     

壳聚糖酶的克隆表达与壳寡糖的制备分析

目的:克隆壳聚糖酶基因于大肠杆菌中实现高表达,制备壳寡糖。方法:以枯草芽孢杆菌总DNA为模板扩增壳聚糖酶基因(CSN),克隆至载体pET23a(+)上,转化菌株BL21(DE3)。重组子经0.5 mmol/L IPTG诱导后,SDS-PAGE和质谱检测与鉴定重组酶。酶纯化后水解壳聚糖,薄层色谱分析其水解产物。结果:质谱证明壳聚糖酶(31.5kDa)成功表达,表达量占菌体总蛋白的45%左右。纯化后重组酶浓度为900 mg/L,纯度95%、回收率85%,酶活力为10 000 U/mg。壳聚糖降解产物为壳二糖至壳四糖。结论:原核表达载体pET23a(+)-CSN构建正确,壳聚糖酶表达量与活性高,适用于水解壳聚糖制备壳寡糖。     

国内外蝗害治理技术现状与展望

本文首先概述了国内外蝗虫发生与为害的态势,总结了现阶段我国蝗虫发生与为害的主要特点:即农田飞蝗暴发频繁而且严重,草原土蝗的发生时常造成严重的经济损失,而且侵入城市干扰市民生活,我国与周边国家之间蝗虫过境迁移频繁,使用化学农药污染环境和农产品;分析了国内外蝗虫防治对策与技术的发展现状,重点介绍了应急防治和可持续治理对策、...     

Synthesis and turnover of cerebrosides and phosphatidylserine of myelin and microsomal fractions of adult and developing rat brain.

The synthesis and turnover of cerebrosides and phospholipids was followed in microsomal and myelin fractions of developing and adult rat brains after an intracerebral injection of [U-14C]serine. The kinetics of incorporation of radioactivity into microsomal and myelin cerebrosides indicate the possibility of a precursor-product relationship between cerebrosides of these membranes. The specific radioactivity of myelin cerebrosides was corrected for the deposition of newly formed cerebrosides in myelin. Multiphasic curves were obtained for the decline in specific radioactivity of myelin and microsomal cerebrosides, suggesting different cerebroside pools in these membranes. The half-life of the fast turning-over pool of cerebrosides of myelin was 7 and 22 days for the developing and adult rat brain respectively. The half-life of the slowly turning-over pool of myelin cerebrosides was about 145 days for both groups of animals. The half-life of the rapidly turning-over microsomal cerebrosides was calculated to be 20 and 40 h for the developing and adult animals respectively. The half-life of the intermediate and slowly turning-over microsomal cerebrosides was 11 and 60 days respectively, for both groups of animals. The amount of incorporation of radioactivity into microsomal cerebrosides from L-serine was greatly decreased in the adult animals, and greater amounts of the precursor were directed towards the synthesis of phosphatidylserine. In the developing animals, considerable amounts of cerebrosides were synthesized from L-serine, besides phosphatidylserine. The time-course of incorporation indicated that a precursor-product relationship exists between microsomal and myelin phosphatidylserine. The half-life of microsomal phosphatidylserine was calculated to be about 8 h for the fast turning-over pool in both groups of animals.     

Identification and composition of the tonsillar and anal enterococcal and streptococcal flora of dogs and cats

Enterococcus faecalis was the most frequently isolated enterococcal species from anal swabs and tonsils of dogs and cats, although in the anal samples from dogs Ent. hirae was found almost as often as Ent. faecalis. Most Ent.faecium strains from dog tonsils differed from those associated with humans and other animals in that they fermented sorbitol. Typical Ent. avium as well as atypical Ent. avium -like strains were seen in dogs, while the related species Ent. raffinosus was associated with cat tonsils. Enterococcus cecorum also occurred mainly in cats. Certain atypical strains, presumptively identified as Ent. cecorum , shared characteristics with Ent. columbae.
The most frequent streptococcal species in tonsils of cats and dogs were Streptococcus suis and Strep. canis. Streptococcus canis and Strep. bovis predominated in anal swabs. The canine Strep. suis differed from the common porcine strains in fermenting mannitol.
Forty-seven of the 288 isolates examined could not be identified or related to known species. The characteristics of two groups of these bacteria, provisionally called 'Ton 31 group' and 'O7 group' are described.     

颧骨颧弓骨折的分类及诊治

颧骨颧弓骨折是最常见的面中部骨折之一,迄今为止,在其分类及诊治的选择上仍然存在一定争议,本文对目前颧骨颧弓骨折的分类及诊治的现状和进展作一综述,以期对临床工作提供参考。     

Molecular characterisation of species and genotypes of Cryptosporidium and Giardia and assessment of zoonotic transmission

The molecular characterisation of species and genotypes of Cryptosporidium and Giardia is essential for accurately identifying organisms and assessing zoonotic transmission. Results of recent molecular epidemiological studies strongly suggest that zoonotic transmission plays an important role in cryptosporidiosis epidemiology. In such cases the most prevalent zoonotic species is Cryptosporidium parvum. Genotyping and subtyping data suggest that zoonotic transmission is not as prevalent in the epidemiology of giardiasis. Molecular characterisation of Cryptosporidium and Giardia is a relatively recent application that is evolving as new genes are found that increase the accuracy of identification while discovering a greater diversity of species and yet unnamed taxa within these two important genera. As molecular data accumulate, our understanding of the role of zoonotic transmission in epidemiology and clinical manifestations is becoming clearer.