乙脑病毒持续感染株preM区序列分析

为了研究乙型脑炎病毒持续感染株preM区域基因序列变异及其意义,我们将两种乙脑病毒野生株(JaGAr-01株和Nakayama株)分别感染人肝癌KN73细胞,经过多次细胞传代后建立乙脑病毒持续感染模型,收集感染细胞经反复冻融获取变异病毒。利用preM区特异引物进行RT-PCR法得到两种病毒的preM区基因片段,应用基因测序反应进行序列分析,并对两种病毒株preM区序列进行比较。preM区基因测序结果显示,与JaGAr-01野生株比较,JaGAr-01持续感染变异株(JaG-per)有1个核苷酸上碱基发生变异(第26位U→G)并导致相应氨基酸发生置换(第9位亮氨酸→精氨酸);Nakayama持续感染变异株(Nak-per)与其野生株相比则有11个核苷酸上碱基存在差异(第26位U→G,第37位G→A,第39位C→U,第45位U→C,第51位U→C,第99位U→C,第126位U→C,第165位C→U,第189位C→U,第195位C→U,第198位U→C),但仅有其中第26位、第37位、第39位的碱基变异引起相应编码的氨基酸发生置换(第9位亮氨酸→精氨酸及第13位缬氨酸→异亮氨酸)。对比还发现变异后的JaGAr-01持续感染株与Nakayama持续感染株的基因序列相同。认为乙脑病毒持续感染变异株preM区存在基因变异,这种变异可能与该区参与病毒持续感染及维持病毒生物学特性有关。     

Effects of antibiotics on modern chronic diseases

The discovery of antibiotics is the miracle of modern medicine,which has contributed greatly to the protection of human health.However,in despite of medical advances to date,some quite inexplicable modern diseases are still haunting us.These chronic diseases are less fierce in fatality,but more permanently compromise the quality of patients′lives.In this paper,the relevant background knowledge about antibiotics were introduced and the relationship between antibiotics and several common chronic diseases was analyzed,in order to promote the rational use of antibiotics and the correct view on antibiotics.     

Virulence variation among epidemic and non-epidemic strains of Saint Louis encephalitis virus circulating in Argentina

Saint Louis encephalitis virus caused an outbreak of febrile illness and encephalitis cases in Córdoba, Argentina, in 2005. During this outbreak, the strain CbaAr-4005 was isolated from Culex quinquefasciatus mosquitoes. We hypothesised that this epidemic variant would be more virulent in a mouse model than two other non-epidemic strains (78V-6507 and CorAn-9275) isolated under different epidemiological conditions. To test this hypothesis, we performed a biological characterisation in a murine model, including mortality, morbidity and infection percentages and lethal infection indices using the three strains. Mice were separated into age groups (7, 10 and 21-day-old mice) and analysed after infection. The strain CbaAr-4005 was the most infective and lethal of the three variants, whereas the other two strains exhibited a decreasing mortality percentage with increasing animal age. The strain CbaAr-4005 produced the highest morbidity percentages and no significant differences among age groups were observed. The epidemic strain caused signs of illness in all inoculated animals and showed narrower ranges from the onset of symptoms than the other strains. CbaAr-4005 was the most virulent for Swiss albino mice. Our results highlight the importance of performing biological characterisations of arbovirus strains likely to be responsible for emerging or reemerging human diseases.     

The blood-testis barrier: the junctional permeability, the proteins and the lipids

The elucidation of how individual components of the Sertoli cell junctional complexes form and are dismantled to allow not only individual cells but whole syncytia of germinal cells to migrate from the basal to the lumenal compartment of the seminiferous epithelium without causing a permeability leak in the blood-testis barrier is amongst the most enigmatic yet, challenging and timely questions in testicular physiology. The intriguing key event in this process is how the barrier modulates its permeability during the periods of formation and dismantling of individual Sertoli cell junctions. The purpose of this review is therefore to first provide a reliable account on the normal formation, maintenance and dismantling process of the Sertoli cells junctions, then to assess the influence of the expression of their individual proteins, of the cytoskeleton associated with the junctions, and of the lipid content in the seminiferous tubules on the regulation of the their permeability barrier function. To help focus on the formation and dismantling of the Sertoli cell junctions, several considerations are based on data gleaned not only from rodents but from seasonal breeders as well because these animal models are characterized by exhaustive periods of junction assembly during development and the onset of the seasonal re-initiation of spermatogenesis as well as by an extensive junction dismantling period at the beginning of testicular regression, something unavailable in normal physiological conditions in continual breeders. Thus, the modulation of the permeability barrier function of the Sertoli cell junctions is analyzed in the physiological context of the blood-epidydimis barrier and in particular of the blood-testis barrier rather than in the context of a detailed account of the molecular composition and signalisation pathways of cell junctions. Moreover, the considerations discussed in this review are based on measurements performed on seminiferous tubule-enriched fractions gleaned at regular time intervals during development and the annual reproductive cycle.     

Development of an ELISA system for tick-borne encephalitis virus infection in rodents

Tick-borne encephalitis (TBE) virus causes severe encephalitis with serious sequelae in humans. An epizootiological survey of wild rodents is effective to detect TBE virus-endemic areas; however, limited serological diagnostic methods are available to detect anti-TBE virus antibodies in wild rodents. In this study, ELISAs for the detection of rodent antibodies against the TBE virus were developed using two recombinant proteins, domain III of the E protein (EdIII) and subviral particles (SPs), as the antigens. As compared with the neutralization test, the ELISA using EdIII had 77.1% sensitivity and 80.0% specificity, and the ELISA using SPs had 91.4% sensitivity and 100% specificity. Furthermore, when the ELISAs were applied to the epizootiological survey in the TBE virus-endemic area, both of the ELISAs was able to detect wild rodents with TBE virus-specific antibodies. This is the first study to show that ELISAs using recombinant antigens can be safe and useful in the detection of TBE virus-infected wild rodents in epizootiological research.     

Divergent Sp1 protein levels may underlie differential expression of UDP-glucose dehydrogenase by fibroblasts: role in susceptibility to orbital Graves disease

UDP-glucose dehydrogenase (UGDH) catalyzes the formation of UDP-glucuronate. Glucuronate represents an integral component of the glycosaminoglycan, hyaluronan, which accumulates in orbital Graves disease. Here we report that orbital fibroblasts express higher levels of UGDH than do those from skin. This is a consequence of greater UGDH gene promoter activity and more abundant steady-state UGDH mRNA. Six Sp1 sites located in the proximal 550 bp of the UGDH gene promoter appear to determine basal promoter activity, as does a previously unrecognized 49-bp sequence spanning -1436 nucleotides (nt) and -1388 nt that negatively affects activity. Nuclear Sp1 protein is more abundant in orbital fibroblasts, and its binding to specific sites on DNA is greater than that in dermal fibroblasts. Mutating each of these Sp1 sites in a UGDH gene promoter fragment, extending from -1387 to +71 nt and fused to a luciferase reporter, results in divergent activities when transfected in orbital and dermal fibroblasts. Reducing Sp1 attenuated UGDH gene promoter activity, lowered steady-state UGDH mRNA levels, and reduced UGDH enzyme activity. Targeting Sp1 and UGDH with specific siRNAs also lowered hyaluronan synthase-1 (HAS-1) and HAS-2 levels and reduced hyaluronan accumulation in orbital fibroblasts. These findings suggest that orbital fibroblasts express high levels of UGDH in an anatomic-specific manner, apparently the result of greater constitutive Sp1. These high UGDH levels may underlie susceptibility of the orbit to localized overproduction of hyaluronan in Graves disease.     

Dual targets for mouse mast cell protease-4 in mediating tissue damage in experimental bullous pemphigoid

Mouse mast cell protease-4 (mMCP-4) has been linked to autoimmune and inflammatory diseases, although the exact mechanisms underlying its role in these pathological conditions remain unclear. Here, we have found that mMCP-4 is critical in a mouse model of the autoimmune skin blistering disease bullous pemphigoid (BP). Mice lacking mMCP-4 were resistant to experimental BP. Complement activation, mast cell (MC) degranulation, and the early phase of neutrophil (PMN) recruitment occurred comparably in mMCP-4(-/-) and WT mice. However, without mMCP-4, activation of matrix metalloproteinase (MMP)-9 was impaired in cultured mMCP-4(-/-) MCs and in the skin of pathogenic IgG-injected mMCP-4(-/-) mice. MMP-9 activation was not fully restored by local reconstitution with WT or mMCP-4(-/-) PMNs. Local reconstitution with mMCP-4(+/+) MCs, but not with mMCP-4(-/-) MCs, restored blistering, MMP-9 activation, and PMN recruitment in mMCP-4(-/-) mice. mMCP-4 also degraded the hemidesmosomal transmembrane protein BP180 both in the skin and in vitro. These results demonstrate that mMCP-4 plays two different roles in the pathogenesis of experimental BP, by both activating MMP-9 and by cleaving BP180, leading to injury of the hemidesmosomes and extracellular matrix of the basement membrane zone.     

温抗体型自身免疫性溶血性贫血的诊治进展

自身免疫性溶血性贫血(AIHI)按照自身抗体作用于红细胞时所需的温度分为温抗体型AIHI(WAIHI)和冷抗体型AIHI(CAIHI),以WAIHI居多,并且多为继发性。WAIHI的发病与温度没有显著的相关关系,其发病是由各种原因引起的免疫机制变异,主要包括基因遗传因素、自身免疫调节异常及免疫因素等,导致针对自身红细胞的抗体产生,再与红细胞膜表面抗原结合,它是一种会使自身红细胞破坏或者缩短寿命的比较难以治疗的贫血,目前治疗AIHI首选疗法为肾上腺皮质激素(激素),有效率可达80%,大剂量静脉注射丙种球蛋白(IVIG)、输血、切除脾等方法的使用也在实践中逐渐增多,并且疗效可观。近年来对温抗体型自身免疫性溶血性贫血的诊治进展的研究越来越多。