丙型肝炎病毒感染实验模型的研究新进展

丙型肝炎病毒(HCV)感染是继乙型肝炎病毒之后引起慢性肝炎、肝硬化以及肝细胞癌的又一主要病因.HCV易感宿主选择有限,至今尚不能建立稳定、易行的HCV感染细胞及动物模型系统,使得病毒变异性、复制机制、与宿主蛋白相互作用以及新药与疫苗研发等相关研究受到极大限制.本文就近年来围绕持续稳定的HCV体外细胞或动物感染模型的研究新进展作一综述.     

丙型肝炎病毒细胞模型和动物模型的研究

建立丙型肝炎病毒(HCV)的细胞模型及动物模型,对于深入认识HCV病原学特点、复制及发病机制,筛选有效药物及疫苗等极为重要。近年来,国内外学者作了大量探讨,概括如下。 1 HCV细胞模型的研究 1.1 HCV感染类细胞模型 1.1.1 以肝细胞为宿主的HCV感染细胞模型 众所周知,人肝细胞是HCV感染的天然宿主细胞,以成人肝细胞作为感染HCV的细胞模型应有更好的代表性。Ito等直接将HCV阳性血清与丙肝患者肝活检分离出来的肝细胞共培养,发现肝细胞内和培养上清液中可检出大量HCV RNA,用     

HBV动物模型研究进展

HBV感染动物模型是研究HBV致病机制、筛选新型有效抗HBV药物和治疗方法的重要工具,然而HBV感染具有高度组织特异性以及种属特异性,这给HBV感染动物模型的建立带来了困难。近年来,随着分子生物学、实验动物学、病毒学及免疫学等相关学科技术的进步,HBV感染或复制动物模型取得了明显进展。目前应用于HBV(包括与HBV具有相似特性的动物肝炎病毒)研究的动物模型主要包括黑猩猩、树鼩、土拨鼠及鸭HBV感染模型,HBV转基因小鼠、高压水动力注射介导的小鼠HBV复制模型和重组腺相关病毒载体介导的小鼠HBV复制模型,以及人源化人-鼠嵌合肝脏HBV感染模型,此外,钠离子-牛磺胆酸共转运蛋白转基因小鼠感染模型是近年的研究热点。本文就上述HBV动物模型的研究进展进行综述。     

丙型肝炎病毒受体研究现状及展望

在HCV感染宿主过程中，病毒首先结合到靶细胞表面，经受体介导进入细胞，然后才能复制、表达病毒蛋白并引起相关的病理变化。因此，HCV宿主细胞表面的受体或辅助受体的研究显得尤为重要。目前难以从感染的血清和组织中分离天然HCV病毒颗粒，此外缺乏有效的体外病毒复制系统和小动物模型，所以，HCV宿主细胞表面受体及HCV感染靶细胞机制仍不太清楚。     

动物模型在丙型肝炎研究中的应用与进展

丙型肝炎呈全球性流行,是引起终末期肝病的主要原因之一。建立理想的动物模型对研究丙型肝炎病毒（HCV ）相关肝病尤为重要。它不仅有利于丙型肝炎疫苗的研究,同时对深入研究丙型肝炎的慢性化致病机制,包括研究病毒变异特性与宿主免疫应答规律等,具有重要意义。但是,缺乏理想的动物模型阻碍了对 HCV的深入研究。     

应用感染性丙型肝炎病毒2a质粒制备小鼠丙型肝炎模型的初步研究

目的制备表达丙型肝炎病毒（HCV）2a型RNA的小鼠模型,为研究HCV高亲和力中和单克隆抗体在体内的病毒清除能力提供可行的动物模型。方法采用引进的HCV 2a型的质粒Jc1,体外表达HCV RNA后转染Huh7细胞,建立可持续感染的Huh7-Jc1丙肝细胞模型。然后以该细胞腹腔注射裸鼠,或以该细胞尾静脉注射裸鼠,并通过小鼠血液中HCV 2a的RNA水平检测,观察小鼠体内的HCV存留情况,以移植未转HCV的Huh7细胞和培养上清为阴性对照。结果建立了可表达HCV RNA和核心蛋白的Huh7-Jc1细胞,且该细胞模型具有一定感染能力,以其培养上清孵育Huh7细胞,可使后者也表达HCV RNA和核心蛋白。BALB/c-nu裸鼠腹腔或尾静脉移植Huh7-Jc1细胞后,裸鼠血清中可检测到HCV RNA的表达。结论显示利用Huh7-Jc1细胞可初步制备表达HCV的丙型肝炎小鼠模型,但高效、长久表达HCV的小鼠模型还有待进一步完善。     

冠状病毒动物模型研究进展及2019-nCoV可能的易感小动物模型

建立高致病性冠状病毒动物模型对疫苗、抗体、药物、病毒致病机制研究意义重大。非人灵长类、雪貂、叙利亚仓鼠等动物均可用于建立冠状病毒的感染和疾病动物模型。不同动物模型能从不同层面模拟重现临床感染症状。然而,从适用性、经济性、易于获取等角度综合考虑,建立冠状病毒易感的小鼠模型,并快速提供数量充足的动物,对于冠状病毒疫情防控更有现实意义。本文简述了MERS-CoV、SARS-CoV以及新型冠状病毒(2019-nCoV)3种高致病性冠状病毒小鼠模型的研究进展。基于近日发表在Nature的研究成果,即SARS-CoV和2019-nCoV均利用hACE2受体感染宿主细胞推测,我们于2018年构建的hACE2-KI/NIFDC人源化小鼠模型有望用于2019-nCoV的相关研究。     

丙型肝炎病毒蛋白在转基因模型中的作用机制研究进展

丙型肝炎病毒(hepatitis C virus,HCV)与肝炎、肝硬化和肝癌的发生密切相关.由于HCV通常只在人和高级灵长类动物中形成自然感染,因此极少有研究建立HCV长期感染的实验室模型,HCV感染的病理生理学变化及其与宿主相互作用的相关研究也因此受到限制.近年来,转基因技术为研究人类疾病的分子机制提供了方法,在此基础上开展的转基因细胞系,嵌合体和转基因动物模型在感染性疾病研究中的价值已得到证实.本文综述了近年来HCV转基因模型中HCV蛋白相关的可能致病机制.     

HCV实验动物模型研究进展

HCV是威胁人类健康的重要病原体之一,可在人体肝脏形成持续性感染,导致慢性肝炎、肝纤维化、肝硬化和肝癌。HCV的实验动物模型不仅是HCV免疫学、病理学和病毒学等基础科学的重要研究手段,还为HCV疫苗和药物的研发提供了关键的工具和平台。黑猩猩是除了人类以外唯一可以被HCV感染的灵长类动物,为HCV的研究做出了重要贡献,但其使用受到了成本及伦理上的限制。近年在利用树鼩和人源化小鼠建立HCV小动物模型的研究上取得良好的进展。本文将总结常用HCV实验动物模型的现状和挑战。     

丙型肝炎病毒感染树鼩的研究进展

丙型肝炎病毒(HCV)感染是世界范围内肝病流行的主要病因,是当前全球关注的严重的公共健康问题之一。建立适用、可靠的HCV感染动物模型,是推动研究HCV感染和慢性化机制、研制HCV疫苗和防治药物所必需。但HCV像其他嗜肝病毒一样具有非常严格的种属特异性,目前除     

胰岛素瘤的解剖分布特点分析

目的胰岛素瘤是最常见的胰腺神经内分泌肿瘤，因其临床表现多样，导致诊断困难。影像学诊断尤其是超声内镜(EUS)在胰岛素瘤的诊断中起着重要作用，拥有较高的敏感性和特异性。本研究拟通过明确胰岛素瘤的解剖分布特点，以期有助于提高影像学的诊断准确率和降低漏诊率，尤其是在教育和培训实践中对于EUS的学习者更具有指导价值。 方法回顾性分析解放军总医院第一医学中心病案资料数据库1993年1月至2019年11月经外科手术、病理确诊为胰岛素瘤的患者的临床资料，检索方法采取搜索术后病理诊断为"胰岛素瘤"的病例，通过查阅病例的方法，提取出胰岛素瘤的大小和解剖分布等数据，进一步分析其特点。 结果共检索到确诊为胰岛素瘤的患者116例，其中，男45例、女71例，年龄13～76岁，平均年龄(44.4±14.85)岁。胰岛素瘤单发110例(94.8%)、多发6例(5.2%)。位置分布：头颈部46例(39.7%)，单发45例、多发1例；体尾部68例(58.6%)，单发65例、多发3例；全胰腺多发2例(1.7%)。病变大小特点：最大径0.4～3.4 cm，平均大小(1.53±0.58)cm。≤1 cm 29例、>1 cm而≤1.5 cm41例、>1.5 cm而≤2.0 cm28例，≤3 cm 15例，>3 cm 3例。年龄与肿瘤的大小相关，≤44岁患者肿瘤平均大小为(1.36±0.51)cm、>44岁患者肿瘤平均大小为(1.70±0.60)cm，P<0.05。头颈部的肿瘤大于体尾部的肿瘤，头颈部肿瘤平均大小(1.66±0.63)cm，体尾部(1.42±0.52)cm，P<0.05。 结论胰岛素瘤在胰腺体尾部较头颈部更好发；绝大多数单发，但可以全胰腺多发；多数小于1.5 cm，肿瘤的大小与患者年龄和肿瘤的解剖分布相关。     

Pathogenesis of carcinoma of the papilla of Vater

Most adenomas and carcinomas of the small intestine and extrahepatic bile ducts arise in the region of the papilla of Vater. In familial adenomatous polyposis (FAP) it is the main location for carcinomas after proctocolectomy. In many cases symptoms due to stenosis lead to diagnosis at an early tumor stage. In about 80%, curative intended resection is possible. Operability is the most relevant prognostic factor. Most ampullary carcinomas resp. carcinomas of the papilla of Vater develop from adenomatous or flat dysplastic precursor lesions. They can be sited in the ampulloduodenal part of the papilla of Vater, which is lined by intestinal mucosa. They also can develop in deeper parts of the ampulla, which are lined by pancreaticobiliary duct mucosa. Intestinal-type adenocarcinoma and pancreaticobiliary-type adenocarcinoma represent the main histological types of ampullary carcinoma. Furthermore, there exist unusual types and undifferentiated carcinomas. Many carcinomas of intestinal type express the immunohistochemical marker profile of intestinal mucosa (keratin 7?, keratin 20+, MUC2+). Carcinomas of pancreaticobiliary type usually show the immunohistochemical profile of pancreaticobiliary duct mucosa (keratin 7+, keratin 20?, MUC2?). Even poorly differentiated carcinomas, as well as unusual histological types, may conserve the marker profile of the mucosa they developed from. These findings underline the concept of histogenetically different carcinomas of the papilla of Vater which develop either from intestinal- or from pancreaticobiliary-type mucosa of the papilla of Vater. Molecular alterations in ampullary carcinomas are similar to those of colorectal as well as pancreatic carcinomas, although they appear at different frequencies. In future studies, molecular alterations in ampullary carcinomas should be correlated closely with the different histologic tumor types. Consequently, the histologic classification should reflect the histogenesis of ampullary tumors from the two different types of papillary mucosa.     

Demonstration of the mechanism of action of biguanides

Summary Palmitic acid oxidation in rat diaphragm homogenate is depressed by biguanide concentrations that are still incapable of inhibiting oxidative phosphorylation. Glucose oxidation is not directly effected by the same biguanide concentrations: however, the inhibitory effect of palmitic acid on glucose oxidation is partly removed by biguanides. Inhibition of fatty acid oxidation, which accounts for most of the metabolic effects caused by these drugs, can be regarded as the fundamental mechanism of action of biguanides. There is some evidence suggesting that these drugs might interact with carnitine, thus preventing long-chain fatty acids from being transported across the mitochondrial membrane to the site of oxidation. Traduzione a cura degli AA.     

Lack of correlation of degree of villous atrophy with severity of clinical presentation of coeliac disease

BACKGROUND AND AIM: Both the clinical presentation and the degree of mucosal damage in coeliac disease vary greatly. In view of conflicting information as to whether the mode of presentation correlates with the degree of villous atrophy, we reviewed a large cohort of patients with coeliac disease. PATIENTS AND METHODS: We correlated mode of presentation (classical, diarrhoea predominant or atypical/silent) with histology of duodenal biopsies and examined their trends over time. RESULTS: The cohort consisted of 499 adults, mean age 44.1 years, 68% females. The majority had silent coeliac disease (56%) and total villous atrophy (65%). There was no correlation of mode of presentation with the degree of villous atrophy (p=0.25). Sixty-eight percent of females and 58% of males had a severe villous atrophy (p=0.052). There was a significant trend over time for a greater proportion of patients presenting as atypical/silent coeliac disease and having partial villous atrophy, though the majority still had total villous atrophy. CONCLUSIONS: Among our patients the degree of villous atrophy in duodenal biopsies did not correlate with the mode of presentation, indicating that factors other than the degree of villous atrophy must account for diarrhoea in coeliac disease.     

血吸虫童虫生长发育及其机制的研究进展

血吸虫童虫是宿主免疫系统攻击的重要靶标,包括皮肤型、肺型和肝门型童虫。宿主分子对童虫生长发育具有重要作用。童虫生长发育机制包括免疫调节、信号转导、性别发育及凋亡等。肌动蛋白、组织蛋白酶、烯醇化酶和葡萄糖基转移酶等分子为血吸虫童虫生长发育的重要分子。本文对血吸虫童虫生长发育及其机制的研究进展做一综述。     

124例耐多药结核分枝杆菌基因突变特征分析

目的对临床分离的耐多药结核分枝杆菌相关基因的突变特征进行分析。方法对124例耐多药结核分枝杆菌以及50株敏感株的耐药相关基因(包括异烟肼inh A、kat G、oxyR-ahp C间隔区以及利福平rpo B)进行序列测定,分析其基因突变情况。结果异烟肼耐药inh A基因突变率为14.5%;kat G基因突变率为70.2%(87/124),主要位于315位;oxyR-ahp C间隔区突变率为15.3%;inh A、kat G两种基因同时突变率75.0%,三种基因同时突变率为89.5%。利福平rpo B基因突变的检出率高达95.2%,突变主要发生在531、526、516位点。结论我省耐多药菌异烟肼耐药相关基因最常见突变为kat G 315、inh A C-T(-15)、axyR-ahp C间隔区(-10)C-T,利福平为rpo B531、526、516。结合MDR-TB耐药相关基因的特征分析,可以建立一种快速、准确、特异的适合于我省的检测结核菌耐多药性的新方法。     

氯硝柳胺悬浮剂的毒性评价

目的评价氯硝柳胺悬浮剂的毒性，为现场大规模应用灭螺提供依据。方法按照中华人民共和国国家标准GB 15670-1995《农药登记毒理学试验方法》和鱼类毒性试验方法进行。结果经口、经皮肤的LDso雌、雄性大鼠均>5 000 mg/kg，经呼吸道的LCso雌、雄性大鼠均>5 000mg/m3，该药经口、经皮肤、经呼吸道毒性均属微毒类药物；兔眼用药后，观察期内无不良反应，对眼无刺激性；皮肤用药后对皮肤无刺激性。与氯硝柳胺原药、氯硝柳胺乙醇胺盐原药和氯硝柳胺乙醇胺盐可湿性粉剂相比，氯硝柳胺悬浮剂对鱼急性毒性最低。结论氯硝柳胺悬浮剂属微毒类药物，对鱼的毒性低于其乙醇胺盐可湿性粉剂，适合于现场应用。     

Assessment of quality of life of parents of children with juvenile chronic arthritis

The aim of the study was to assess the quality of life (QOL) and the psychological status of parents of children with juvenile chronic arthritis (JCA). The QOL, anxiety and depression of the parents of 28 children with JCA were evaluated and compared to those of the parents of 28 healthy children. Mothers of JCA children and mothers of healthy children reported similar QOL. The reported anxiety and depression levels were similar for mothers and fathers in both groups. The parents of children with pauciarticular-type JCA reported lower QOL and higher levels of anxiety and depression than the parents of children with other types, namely polyarticular and systemic JCA. These findings may be explained by the fact that the pauciarticular patients had shorter disease duration and were less frequently seen in the outpatient clinic. The QOL of mothers of children with JCA was found to be slightly impaired in the group of children with pauciarticular JCA. Future larger studies are needed to confirm these results, as the number of subjects in the three groups was rather low. Received: 26 September 2001 / Accepted: 8 February 2002     

Numerical Simulation of the Effect of Rate of Change of Glucose on Measurement Error of Continuous Glucose Monitors

Background

A 5-day in-patient study designed to assess the accuracy of the FreeStyle Navigator® Continuous Glucose Monitoring System revealed that the level of accuracy of the continuous sensor measurements was dependent on the rate of glucose change. When the absolute rate of change was less than 1 mg•dl⁻¹•min⁻¹ (75% of the time), the median absolute relative difference (ARD) was 8.5%, with 85% of all points falling within the A zone of the Clarke error grid. When the absolute rate of change was greater than 2 mg•dl⁻¹•min⁻¹ (8% of the time), the median ARD was 17.5%, with 59% of all points falling within the Clarke A zone.

Method

Numerical simulations were performed to investigate effects of the rate of change of glucose on sensor measurement error. This approach enabled physiologically relevant distributions of glucose values to be reordered to explore the effect of different glucose rate-of-change distributions on apparent sensor accuracy.

Results

The physiological lag between blood and interstitial fluid glucose levels is sufficient to account for the observed difference in sensor accuracy between periods of stable glucose and periods of rapidly changing glucose.

Conclusions

The role of physiological lag on the apparent decrease in sensor accuracy at high glucose rates of change has implications for clinical study design, regulatory review of continuous glucose sensors, and development of performance standards for this new technology. This work demonstrates the difficulty in comparing accuracy measures between different clinical studies and highlights the need for studies to include both relevant glucose distributions and relevant glucose rate-of-change distributions.     

Study of constancy of hydrogen-consuming flora of human colon

The constancy of the hydrogen consuming flora of the human colon was studied in 15 healthy subjects via two measurements obtained 18 to 36 months apart. Hydrogen disappearance rate and the major products of H₂-consuming bacteria, methane and sulfide, were measured during incubation of fecal homogenates with excess hydrogen and sulfate. In 11/15, the hydrogen consumption rate and the predominant hydrogen-consuming pathway (methanogenesis, sulfate reduction, or neither) remained constant. However, major shifts in these pathways were observed in four subjects, with two losing and two gaining the ability to produce methane. Methanogenesis was associated with the highest hydrogen consumption rate. This study demonstrates that clinically unrecognizable, major alterations of the colonic flora occur in healthy subjects. Understanding of the factors responsible for these alterations might allow for therapeutic manipulation of the colonic flora.Supported in part by the Department of Veterans Affairs and NIDDKD RO1 DK 13309-25.