丙型肝炎5''''非编码区末端快速基因扩增方法的建立及应用

目的 建立快速获得丙型肝炎（HCV）基因组5’非编码区（5’uTR）真末端序列的分子生物学方法。方法 逆转录后利用末端聚合酶（TOT）进行加尾反应，再利用套式聚合酶链反应（PCR）扩增出目的末端基因的cDNA片段，A-T克隆，用限制性内切酶片段长度多态性分析（RVLP）与PCR鉴定重组子，全自动序列分析仪测定插入子序列。结果 cDNA末端快速扩增技术（RACE）获得5株HCV5’UTR克隆，包括3株全长克隆和2株缺失克隆。2株缺失克隆，一条在5’末端缺失53个碱基，另一条缺失144个碱基。结论 RACE技术快速、有效、实用，可有效获得丙型肝炎病毒基因组的5’非编码区末端序列。     

Histamine-induced vasodilations mediated by H1- and H2-receptors in isolated rat common carotid arteries

Summary Using the cannula inserting method, the vasodilatory effects of histamine were analysed employing selective histamine H₁- and H₂-receptor agonists and antagonists in isolated, perfused rat common carotid arterial preparations which were preconstricted by a continuous infusion of phenylephrine with propranolol. Histamine, 2-pyridylethylamine (2-PEA) (a selective H₁-agonist) and dimaprit (a selective H₂-agonist) produced a vasodilation in a dose-related manner. The order of potency was histamine > dimaprit > 2-PEA. Histamine-induced dilations were significantly inhibited by either diphenhydramine (a selective H₁-antagonist) or cimetidine (a selective H₂-antagonist). 2-PEA-induced dilations were significantly inhibited by diphenhydramine but not by cimetidine. Dimaprit-induced dilations were significantly blocked by cimetidine but not by diphenhydramine. ACh-, histamine-, 2-PEA- and dimaprit-induced dilations were significantly suppressed by removal of the endothelium. From these results, it is concluded that (1) isolated rat common carotid arteries have both H₁-and H₂-receptors, (2) there are few vasoconstrictory H₁-receptors, (3) both H₁- and H₂-receptors mediate only vasodilation but not vasoconstriction, and (4) EDRF from the endothelium might participate in histamine-induced vasodilation via not only H₁- but also H₂-receptors.     

The closing survival gap after liver transplantation for hepatocellular carcinoma in the United States

BackgroundSocio-economic inequalities among different racial/ethnic groups have increased in many high-income countries. It is unclear, however, whether increasing socio-economic inequalities are associated with increasing differences in survival in liver transplant (LT) recipients.MethodsAdults undergoing first time LT for hepatocellular carcinoma (HCC) between 2002 and 2017 recorded in the Scientific Registry of Transplant Recipients (SRTR) were included and grouped into three cohorts. Patient survival and graft survival stratified by race/ethnicity were compared among the cohorts using unadjusted and adjusted analyses.ResultsWhite/Caucasians comprised the largest group (n=9,006, 64.9%), followed by Hispanic/Latinos (n=2,018, 14.5%), Black/African Americans (n=1,379, 9.9%), Asians (n=1,265, 9.1%) and other ethnic/racial groups (n=188, 1.3%). Compared to Cohort I (2002-2007), the 5-year survival of Cohort III (2012-2017) increased by 18% for Black/African Americans, by 13% for Whites/Caucasians, by 10% for Hispanic/Latinos, by 9% for patients of other racial/ethnic groups and by 8% for Asians (All P values<0.05). Despite Black/African Americans experienced the highest survival improvement, their overall outcomes remained significantly lower than other ethnic∕racial groups (adjusted HR for death=1.20; 95%CI 1.05-1.36; P=0.005; adjusted HR for graft loss=1.21; 95%CI 1.08-1.37; P=0.002).ConclusionThe survival gap between Black/African Americans and other ethnic/racial groups undergoing LT for HCC has significantly decreased over time. However, Black/African Americans continue to have the lowest survival among all racial/ethnic groups.     

Early IFN type I response: Learning from microbial evasion strategies

Type I interferon (IFN) comprises a class of cytokines first discovered more than 50 years ago and initially characterized for their ability to interfere with viral replication and restrict locally viral propagation. As such, their induction downstream of germ-line encoded pattern recognition receptors (PRRs) upon recognition of pathogen-associated molecular patterns (PAMPs) is a hallmark of the host antiviral response. The acknowledgment that several PAMPs, not just of viral origin, may induce IFN, pinpoints at these molecules as a first line of host defense against a number of invading pathogens. Acting in both autocrine and paracrine manner, IFN interferes with viral replication by inducing hundreds of different IFN-stimulated genes with both direct anti-pathogenic as well as immunomodulatory activities, therefore functioning as a bridge between innate and adaptive immunity. On the other hand an inverse interference to escape the IFN system is largely exploited by pathogens through a number of tactics and tricks aimed at evading, inhibiting or manipulating the IFN pathway, that result in progression of infection or establishment of chronic disease.In this review we discuss the interplay between the IFN system and some selected clinically important and challenging viruses and bacteria, highlighting the wide array of pathogen-triggered molecular mechanisms involved in evasion strategies.     

Hepatitis C virus infection in children: How do we prevent it and how do we treat it?

Introduction: Hepatitis C virus (HCV) infection is an important contributor to the worldwide burden of liver-related morbidity and mortality. Mother-to-child transmission of HCV ranges from 6 to 11% in different populations globally, but accurate estimates on the burden of pediatric HCV infection are limited because screening approaches are not consistent.

Areas covered: The advent of new direct-acting antiviral agents that achieve very high rates of sustained virologic response (representing virologic cure) with short (i.e. 8–12 weeks) regimens has revolutionized the field of HCV treatment and led to the development of global elimination goals for HCV transmission and mortality. However, information on their safety during pregnancy and efficacy in preventing mother-to-child transmission is lacking. Currently, there are no approved treatment regimens with these antiviral agents for children younger than 12 years of age.

Expert commentary: If these agents are shown to be safe during pregnancy and effective in preventing transmission to the infant, screening of pregnant women and antenatal treatment of those infected, could pave the way for eliminating pediatric HCV infection- particularly as these drugs become less costly and more accessible. Treatment of infected children when indicated, along with universal safe health care practices, can further pediatric HCV elimination.     

Systemic immune responses to an inactivated,whole H9N2 avian influenza virus vaccine using class B CpG oligonucleotides in chickens

Commercial vaccines against avian influenza viruses (AIV) in chickens consist mainly of inactivated AIV, requiring parenteral administration and co-delivery of an adjuvant. Limitations in T helper 1 or T helper 2 biased responses generated by these vaccines emphasize the need for alternative, more efficacious adjuvants. The Toll-like receptor (TLR) 21 ligand, CpG oligodeoxynucleotides (ODN), has been established as immunomodulatory in chickens. Therefore, the objective of this study was to investigate the adjuvant potential of high (20 μg) and low (2 μg) doses of CpG ODN 2007 (CpG 2007) and CpG ODN 1826 (CpG 1826) when administered to chickens with a formalin-inactivated H9N2 AIV. Antibody responses in sera were evaluated in 90 specific pathogen free (SPF) chickens after intramuscular administration of vaccine formulations at 7 and 21 days post-hatch. Antibody responses were assessed based on haemagglutination inhibition (HI) and virus neutralization (VN) assays; virus-specific IgM and IgY antibody responses were evaluated by ELISA. The results suggest that the vaccine formulation containing low dose CpG 2007 was significantly more effective at generating neutralizing (both HI and VN) responses than formulations with high or low doses of CpG 1826 or high dose CpG 2007. Neutralizing responses elicited by low dose CpG 2007 significantly exceeded those generated by a squalene-based adjuvanted vaccine formulation during peak responses. A significantly higher IgM response was elicited by the formulation containing low dose CpG 2007 compared to high and low doses of 1826. Although the low dose of CpG 2007 elicited a higher IgY response than CpG 1826, the difference was not statistically significant. In conclusion, 2 μg of CpG 2007 is potentially promising as a vaccine adjuvant when delivered intramuscularly with inactivated H9N2 virus to chickens. Future studies may be directed at determining the mucosal antibody responses to the same vaccine formulations.     

ELISA法、荧光免疫法及PCR检测婴幼儿腹泻常见病毒

目的 了解不同方法学检测婴幼儿腹泻常见病毒的检测结果差异及一致性情况.方法 采用酶联免疫吸附试验(ELISA)、免疫荧光法(四联法)及聚合酶链式反应(PCR)技术筛查深圳市福田区引起临床婴幼儿急性腹泻的轮状病毒(RV)、肠道腺病毒(EAdV)、诺如病毒(NV)和星状病毒(AstV)的抗原,并将检测结果数据进行对比.结果酶免法与荧光免疫法检测数据对比:对RV,NV,EAdV的抗原阳性检出率差异有统计学意义(P＜0.05),对AstV抗原阳性检出率差异无统计学意义(P＜0.05);两种方法对RV的检测结果具有较好的一致性(Kappa值为0.558),对NV,EAdV和AstV的检测结果一致性较差(Kappa值分别为0.142,-0.025和0.361);ELISA法和PCR检测数据对比:ELISA法除对EAdV阳性检出率低于PCR外,对其他3种病毒的阳性检出率均高于PCR,且经x2检验显示两种方法对4种病毒的阳性检出率差异均有统计学意义(P＜0.05).两种方法对RV,NV,AstV的检测结果具有很好的一致性(Kappa值均＞0.75),对EAdV的检测结果一致性较好(Kappa值为0.537);荧光免疫法(四联法)和PCR检测数据对比:除AstV外,两种方法对其他3种病毒的阳性检出率差异均有统计学意义(P＜0.05).对RV的检测结果具有很好的一致性(Kappa值为0.764),对EAdV的检测结果一致性较好(Kappa值为0.452),NV和AstV的检测结果一致性差(Kappa值分别为0.181和-0.017).结论 ELISA法和荧光免疫法(四联法)对腹泻病毒的检测,除轮状病毒外,其它病毒检测结果的一致性较差,只可用于腹泻病原的初步筛查,确认必须进一步做培养或分子诊断;ELISA法、荧光免疫法(四联法)与PCR三者间的阳性检出率差异均有统计学意义,ELISA法与PCR检测结果的一致性明显较好.以PCR检测结果作为评估标准,ELISA法对四种腹泻病毒抗原的检测灵敏度、特异性及准确性均优于荧光免疫法,荧光免疫法检测结果的假阳性率较高.