可溶性gp130和gp130反义核酸对IL-6诱导的靶基因启动子活性的影响

ｇｐ１３０是ＩＬ－６信号转导子，ＩＬ－６介导的信号转导起始于ｇｐ１３０与ＩＬ－６、ＩＬ－６Ｒα形成的复合物。为了研究ｇｐ１３０胞外区的结构与功能，在肝癌细胞ＨｅｐＧ２中建立了检测ＩＬ－６诱导基因表达强弱的方法，并观察了含胞外区全长（５９７个氨基酸）及氨基端３０４个氨基酸残基的ｇｐ１３０突变体，以及ｇｐ１３０反义核酸对ＩＬ－６生物学效应的影响。证明两个突变体和反义核酸均拮抗ＩＬ－６信号，为进一步研究ＩＬ－６受体拮抗剂奠定了基础。     

HCV NS3 N末端部分氨基酸缺失对NS3/NS3与NS3/NS4A分子间相互作用的影响

目的旨在弄清ＮＳ３参与分子间相互作用的确切区段，为研究针对ＮＳ３的抗ＨＣＶ寡肽小分子药物的设计提供依据。方法参照ＨＣＶ中国河北株序列设计ＮＳ３引物，将其Ｎ末端的前１５个和前３０个氨基酸分别缺失掉。然后用酵母双杂交系统检测ＮＳ３／ＮＳ３及ＮＳ３／ＮＳ４Ａ分子间相互作用强度在缺失前后的变化，从而判明ＮＳ３Ｎ末端氨基酸在分子间相互作用中的意义。核苷酸序列分析采用ＡｐｐｌｉｅｄＢｉｏｓｙｓｔｅｍ３７３Ａ型自动测序仪。结果ＮＳ３Ｎ末端氨基酸缺失前后，ＮＳ３／ＮＳ３分子间及ＮＳ３／ＮＳ４Ａ分子间相互作用的强度相差有显著性（Ｐ＜０．０１），但缺失１５个氨基酸和缺失３０个氨基酸对上述相互作用强度的影响差异无显著性（Ｐ＞０．０５）。结论ＮＳ３Ｎ末端的１～３０个氨基酸在ＮＳ３／ＮＳ３及ＮＳ３／ＮＳ４Ａ分子间相互作用中有一定意义，其Ｎ末端前１５个氨基酸（ＡＰＩＴＡＹＳＱＱＴＲＧＬＬＧ）对于分子间相互作用更为关键。本研究结果将为抗ＮＳ３丝氨酸蛋白酶活性的寡肽抑制物的研究打下基础，并为抗ＨＣＶ的寡肽小分子药物的设计提供依据     

Characterization and phylogenetic analysis of a neurovirulent Zika virus isolated from Cambodia in 2019

The geographic range of Zika virus (ZIKV) has expanded from Asia to the Americas, leading to the 2015–2016 pandemic with enhanced neurovirulence. At present, ZIKV is continuously circulating in many Southeast Asian countries. Unfortunately, the persistent evolution of ZIKV in Southeast Asia and its influence on the biological characteristics of the virus remain incompletely understood. In this study, the in vitro and in vivo properties of a new ZIKV isolate obtained from Cambodia in 2019 (CAM/2019) were characterized and compared with those of the Cambodian strain (CAM/2010). Compared with CAM/2010, the CAM/2019 virus showed similar plaque morphology and growth curves in cell cultures and induced comparable viremia and organ viral loads profiles in both BALB/c and A129 (IFNAR1^−/−) mice upon intraperitoneal (i.p.) inoculation. Remarkably, the CAM/2019 virus exhibited enhanced neurovirulence in neonatal mice compared with CAM/2010, with a 74-fold reduction in the 50% lethal dose (LD₅₀). Consistently, CAM/2019 produced higher viral loads in the brains of BALB/c neonatal mice than CAM/2010 did. Sequence alignment showed that the CAM/2019 virus has acquired 12 amino acid substitutions, several of which were found to be associated with neurovirulence. In particular, the CAM/2019 virus shared an A1204T substitution in NS2A with the Thai isolate SI-BKK02 that was isolated from a microcephaly case. Taken together, our results indicate that a ZIKV strain isolated with specific mutations has emerged in Cambodia, highlighting the need for extensive molecular and disease surveillance in Cambodia and other Asian countries.     

How do health care professionals assess patients when initiating insulin therapy? A qualitative study

AimsTo explore how health care professionals (HCPs) assess patients when initiating insulin therapy in type 2 diabetes.MethodsFocus group discussions and in-depth interviews were conducted with 41 health care professionals in Malaysia in 2010–2011. A semi-structured topic guide was used for the interview. The interviews were transcribed verbatim and analysed using the Nvivo9 software based on a thematic approach.ResultsHCPs were less likely to initiate insulin therapy in patients who were older, with irregular dietary patterns and poor financial status. They also assessed patients’ knowledge, views and misconceptions of insulin. However, there was a variation in how doctors assessed patients’ comorbidities before starting insulin therapy. Medical officers were more likely to initiate insulin therapy in patients with comorbidities and complications, whereas family medicine specialists were more cautious. In addition, most HCPs considered patients’ psychosocial status, including self-care ability, social support and quality of life.ConclusionsHCPs’ assessment of patients’ need to start insulin therapy depends on their perception rather than objective evaluation of patients’ background, knowledge, perception and abilities. The background and the type of practice of HCPs influence their assessment.     

Avian eyelid assay, a new diagnostic method for detecting botulinum neurotoxin serotypes A, B and E.

Based upon botulinum neurotoxins' (BoNT) mechanism of action, a novel, rapid, and sensitive avian eyelid assay was developed to detect Clostridium botulinum neurotoxin serotypes A, B and E in assay buffer and mimic samples. It showed that chick was the most optimal model of 20-selected laboratory, non-laboratory animals. The eyelid closure of chick was the indicator symptom for positive results. The detection limits achieved range from 5 to 250 mouse LD(50) for toxin types A, B, and E in a buffer system and mimic samples. No cross reactivity occurred when using staphylococcal enterotoxin B, diphtheria toxin and nerve agent sarin, but cross reactivity was obtained in more than 6h for using high dose of tetanus toxin. This cross reactivity can be differentiated by BoNT neutralization tests with a serotype-specific antiserum in parallel. The avian eyelid assay can be performed within as short a time as 0.4-6 h. We report here the development of avian eyelid assay is the second animal bioassay for the detection of toxin types A, B, and E which approaches the sensitivity of the mouse bioassay, and is simple to perform as well as rapid to yield results.     

高功率微波对大鼠免疫组织活性氧水平的影响

目的观察高功率微波辐照对大鼠免疫组织细胞内活性氧水平的影响。方法采用DCFH-DA分子探针结合流式细胞仪检测大鼠免疫组织细胞内经0、10、30、50mW/cm2微波辐照后不同时间活性氧水平的变化。结果①骨髓、淋巴结在0～30mW/cm2范围内活性氧水平出现规律性增高,在50mW/cm2时有所降低;脾脏在0～50mW/cm2范围内呈剂量依赖性增高;而胸腺组织虽有增高但未见明显的量效关系。②照后1d活性氧水平升高最为显著,3d出现明显降低,除骨髓高于对照组外,脾脏、淋巴结基本恢复正常。7d时全部恢复到对照水平。结论微波辐照可诱导大鼠免疫组织细胞内活性氧水平升高,在一定剂量范围内呈较好的量效和时效关系。     

搜索引擎的个性化发展趋势

 

从用户需求和搜索引擎市场竞争两个方面论述了搜索引擎个性化发展的背景及个性化的内涵，重点分析近年来国内外搜索引擎推出的个性化搜索和个性化服务及其发展趋势。

     

北京东灵山地区鼠类体外寄生蚤群落的研究

目的：研究北京东灵山地区鼠类体外寄生蚤类群落结构。方法：用群落生态学方法计算群落结构，多样性和相似性指数。结果：1998年6月至1999年5月在该地区的3类生镜中共采集到鼠类体外蚤类16种582匹。农田和灌丛中各类寄生蚤群落优势明显，均匀度较低，在森林却不明显，均匀度较高，窄板额蚤为黑线姬鼠和大林姬鼠蚤类群落优势种，曲鬃怪蚤为社鼠蚤类群落优势种；二齿新蚤为大仓鼠蚤类群落优势种；原双刘为棕背鼠平蚤类群落优势种。结论：主要鼠处体外寄生蚤类群落结构复杂，生物多样性指数较高。     

北京东灵山地区鼠类体外寄生恙螨群落的研究

目的：研究北京东灵山地区鼠类体外寄生恙螨群落结构。方法：1998年6月至1999年5月在该地区的3类生境中，用群落生态学方法计算群落结构，多样怀和相似性指数。结果；共采集鼠类体外恙螨7种1780只，农田和灌丛中各类寄生虫群落优势种明显，在森林却不明显；恙螨群落中，东方纤恙螨为不同鼠种的优势种。结论：主要鼠种体外寄生恙螨群落结构简单，生物多样性指数较低。     

造血干/祖细胞体外定向诱导分化为粒细胞的研究

为探讨利用人造血干/祖细胞体外定向诱导分化的人粒细胞应用于临床大剂量放，化疗后预防感染的可行性，利用源自人胎盘脐带血的CD34^ 细胞及SCF，IL-3，IL-6和G-CSF的细胞因子组合的培养条件。体外进行向粒细胞的诱导分化。结果表明，在该体系条件下可诱导分化出约1000倍数量的细胞，流式细胞仪检测诱导效率可达60%以上。且诱导分化的细胞染色体未出现异常。裸鼠致瘤实验表明该细胞不具致瘤性。细胞体外生长14-21天为高峰，33天后细胞不再增殖，且诱导分化出的细胞具有吞噬细菌的功能。结论：利用细胞工程的方法体外“生产”出的粒细胞具有应用安全性，且具备生理状态下产生的此种细胞应具备的基本功能。为其临床应用提供了基础。