流行性出血热(EHF)Ⅱ型疫苗生产中病毒株及原液的质控检测

流行性出血热Ⅱ型纯化疫苗(即亚单位疫苗)系用Ⅱ型Hautaan病毒R_(22)SM株感染乳鼠脑精制而成。为了保证疫苗生产和质量控制,我们对病毒株的繁殖量,感染度,毒力及纯毒株的中和指数作了实验性检测,依据检测的结果:用Ⅱ型EHF毒株R_(22)SM株乳鼠脑内接种感染后的第4或5天病毒在脑内开始出现,而大量繁殖则在接种感染后第7～8。其单一鼠脑内病毒繁殖量(病毒滴度)和制成单一收获原液中病毒含量基本相一致;脑内病毒滴度log LD_(50)为9.7;原悬液中病毒滴度log ID_(50)为11.2,纯毒试验的特异性中和指数为1378。如上所述,各种实验检测结果完全符合EHF疫苗生产规程指标要求。     

Retention and attempted mechanical transmission of Ehrlichia risticii by Stomoxys calcitrans

Abstract. The ability of adult Stomoxys calcitrans (L.) (Diptera: Muscidae) to retain viable Ehrlichia risticii (Rickettsiaceae), the aetiologic agent of Potomac horse fever (PHF), and mechanically transmit the pathogen from citrated bovine blood artificially infected with E.risticii to susceptible mice was studied. Viable E. risticii were found in the digestive tract of S.calcitrans 3h after the flies had engorged to repletion on infected blood; however, no E. risticii were detected in flies ≥2 days after feeding. Subsequently, groups of S.calcitrans were fed for 20 s on infected blood, then fed to repletion on mice 30, 60,130, 180 or 220 min after having feeding interrupted. Mice displayed no clinical signs of PHF and did not produce anti- E. risticii antibodies when assayed 30 days after S. calcitrans had fed. Although S.calcitrans were able to harbour viable E.risticii for at least 3h, transmission of the disease agent to susceptible mice during interrupted feeding was not demonstrated under these experimental conditions.     

Retrospective and predictive systems of information on airborne pollen concentrations in relation to hay fever

Summary In this survey, the most important aspects concerning information on airborne pollen concentrations in relation to hay fever are reported. Six of these aspects are briefly discussed. They are: target group, “spectivity”, subject exactness, routes, frequency. These aspects of information system can concern airborne pollen and/or pollinosis. The “Leiden” system has two flows of information: daily hay-fever forecast and weekly pollen bulletin.     

Message in a bottle: lessons learned from antagonism of STING signalling during RNA virus infection

STING has emerged in recent years as an important signalling adaptor in the activation of type I interferon responses during infection with DNA viruses and bacteria. An increasing body of evidence suggests that STING also modulates responses to RNA viruses, though the mechanisms remain less clear. In this review, we give a brief overview of the ways in which STING facilitates sensing of RNA viruses. These include modulation of RIG-I-dependent responses through STING's interaction with MAVS, and more speculative mechanisms involving the DNA sensor cGAS and sensing of membrane remodelling events. We then provide an in-depth literature review to summarise the known mechanisms by which RNA viruses of the families Flaviviridae and Coronaviridae evade sensing through STING. Our own work has shown that the NS2B/3 protease complex of the flavivirus dengue virus binds and cleaves STING, and that an inability to degrade murine STING may contribute to host restriction in this virus. We contrast this to the mechanism employed by the distantly related hepacivirus hepatitis C virus, in which STING is bound and inactivated by the NS4B protein. Finally, we discuss STING antagonism in the coronaviruses SARS coronavirus and human coronavirus NL63, which disrupt K63-linked polyubiquitination and dimerisation of STING (both of which are required for STING-mediated activation of IRF-3) via their papain-like proteases. We draw parallels with less-well characterised mechanisms of STING antagonism in related viruses, and place our current knowledge in the context of species tropism restrictions that potentially affect the emergence of new human pathogens.     

Glycoconjugate vaccines against Salmonella enterica serovars and Shigella species: existing and emerging methods for their analysis

The global spread of enteric disease, the increasingly limited options for antimicrobial treatment and the need for effective eradication programs have resulted in an increased demand for glycoconjugate enteric vaccines, made with carbohydrate-based membrane components of the pathogen, and their precise characterisation. A set of physico-chemical and immunological tests are employed for complete vaccine characterisation and to ensure their consistency, potency, safety and stability, following the relevant World Health Organization and Pharmacopoeia guidelines. Variable requirements for analytical methods are linked to conjugate structure, carrier protein nature and size and O-acetyl content of polysaccharide. We investigated a key stability-indicating method which measures the percent free saccharide of Salmonella enterica subspecies enterica serovar Typhi capsular polysaccharide, by detergent precipitation, depolymerisation and HPAEC-PAD quantitation. Together with modern computational approaches, a more precise design of glycoconjugates is possible, allowing for improvements in solubility, structural conformation and stability, and immunogenicity of antigens, which may be applicable to a broad spectrum of vaccines. More validation experiments are required to establish the most effective and suitable methods for glycoconjugate analysis to bring uniformity to the existing protocols, although the need for product-specific approaches will apply, especially for the more complex vaccines. An overview of current and emerging analytical approaches for the characterisation of vaccines against Salmonella Typhi and Shigella species is described in this paper. This study should aid the development and licensing of new glycoconjugate vaccines aimed at the prevention of enteric diseases.     

Review: Dietary cation-anion difference to prevent hypocalcemia with emphasis on over-acidification in prepartum dairy cows

Hypocalcemia remains a common metabolic disorder of dairy cattle; therefore, an efficient prevention is still challenging. Among the various prevention strategies for hypocalcemia is the use of anionic compounds to induce a mild metabolic acidosis during the prepartum period. Acid-base status can be readily assessed through urine pH. Accordingly, a target urine pH during the prepartum period between 6.0 and 6.8 has been recommended for Holstein cows; however, in several countries, including the US, certain nutritional strategies are still focused on benchmarking the urine pH to below 6.0. Unfortunately, over-acidification can have no advantages and/or detrimental effects on both the dam and her offspring. In this review, updated information regarding the use of anionic diets on prepartum dairy cows and the potential negative impact of such diets on both cow and calf performance are discussed. There is an urgent need for studies that will elucidate the pathophysiological mechanisms by which very acidotic diets may impact the well-being and productive efficiency of dairy cows, and the transgenerational effects of such diets on offspring performance and survival.     

无痛分娩产妇生产期间导致产妇出现发热的影响因素与预防措施

摘要 目的：探讨无痛分娩产妇生产期间导致产妇出现发热的影响因素与预防措施。方法：选取我院2020年1月到2020年12月共收治的60例无痛分娩生产期间发热的产妇作为研究对象，将其分为观察组，另取同期60例无痛分娩生产期间未发生发热的产妇作为对照组。对所有产妇进行临床资料分析，对比两组产妇的人口学特征、妊娠基础疾病情况以及产时不同情况，并对所有相关因素进行多因素logistic回归分析。最后进行总结分析，并提出无痛分娩产妇生产期间发热的预防措施。结果：两组产妇的年龄、孕周、孕次、死胎史对比无明显差异（P＞0.05），观察组产妇有保胎史的例数明显高于对照组，观察组产次明显低于对照组（P＜0.05）；两组产妇妊娠期贫血、妊娠期甲状腺功能异常、妊娠期高血压、妊娠期糖尿病、早产情况对比无明显差异（P＞0.05），观察组胎膜早破产妇人数明显高于对照组（P＜0.05）；观察组产妇的第一产程时间、第二产程时间以及胎膜早破距离分娩时间明显高于对照组（P＜0.05），观察组产妇的常规剂量罗哌卡因麻醉使用、人工破膜、宫缩素使用以及羊水污染人数明显高于对照组（P＜0.05）；对所有因素进行赋值，其中"是"或"有"为1，"否"或"无"为0，其他因素依照数值变量赋值。通过logistic回归分析发现，只有保胎史、产次、第一产程时间、第二产程时间、胎膜早破据分娩时间、硬膜外麻醉药物、宫缩素使用以及羊水污染为无痛分娩生产期间产妇发热的独立危险因素（P＜0.05）。结论：无痛分娩产妇的胎膜早破情况、破膜方式可能与产妇出现发热的情况具有一定相关性，但是只有保胎史、产次、第一产程时间、第二产程时间、胎膜早破据分娩时间、硬膜外麻醉药物、宫缩素使用以及羊水污染是产妇出现发热情况的独立危险因素，因此临床上要对初产妇、有保胎史、产程时间长、胎膜早破据分娩时间长、羊水污染等无痛分娩产妇给予一定预防措施，并调整硬膜外麻醉药物的使用，减少宫缩素使用，来避免无痛分娩产妇在生产期间出现的发热现象。