日本血吸虫混合与单性感染雌虫的形态观察及凋亡检测

日本血吸虫混合与单性感染雌虫在形态上存在明显的差异,为了更进一步观察二者生殖器官的差异,本研究采用激光共聚焦观察感染雌虫卵巢和卵黄腺,透射电镜观察卵黄腺,并用原位末端转移酶标记法观察卵黄腺的凋亡水平。激光共聚焦结果表明,混合感染雌虫卵巢和卵黄腺可见成熟的细胞而单性感染雌虫仅存在未成熟的细胞;透射电镜结果表明两者卵黄腺细胞的细胞核和核仁在大小及形态方面有很大差异,混合感染雌虫可见明显的卵黄滴,单性感染雌虫无卵黄滴但有聚集和散在分布的脂滴;原位末端转移酶标记法结果表明,两者皆未呈现明显的凋亡现象。可见,混合与单性感染雌虫不仅在虫体大小和器官形态上,细胞形态和亚细胞结构也存在差异。

日本血吸虫单性感染虫体与复性感染虫体的比较

目的对单性感染或复性感染钉螺的日本血吸虫发育结果进行观察。方法采用单个毛蚴感染单个钉螺,26℃恒温箱中饲养,60 d后逸蚴感染小白鼠(单性感染),40 d后解剖小白鼠,以检获的成虫性别鉴别各个钉螺中的尾蚴性别。再分别以单性尾蚴和混合双性尾蚴感染鼠、兔,40 d后解剖观察宿主感染情况及虫体。结果单性感染小鼠和兔后解剖获得日本血吸虫雄虫或雌虫。复性感染小鼠或兔后检出的虫体主要有3种形态:雌雄合抱、雄虫和雌虫,极少数能看到雄虫合抱未发育成熟雌虫的现象。单性感染的鼠、兔肝脏均未见虫卵,而复性感染的鼠、兔肝脏均查见虫卵。单性感染的雄虫能发育成熟,但体型较合抱成熟的雄虫略小,仅凭肉眼难以与合抱成熟雄虫区分;而单性感染的雌虫则不能发育成熟,镜下卵巢不易见到或仅见到雏形,体型明显细小。结论单性感染的雄虫和雌虫体型比复性感染合抱成熟的雄虫和雌虫的体型小,单性感染的雄虫能发育成熟,而雌虫则不能发育成熟。在解剖哨鼠时,即使未查见肝脏虫卵,仍需检查肠粘膜血管中是否有单性感染的血吸虫。

Pure red cell aplasia due to parvovirus B19 infection after liver transplantation:A case report and review of the literature

Pure red cell aplasia （PRCA） due to parvovirus B19 （PVB19） infectiori after solid organ transplantation has been rarely reported and most of the cases were renal transplant recipients, Few have been described after liver transplantation. Moreover, little information on the management of this easily recurring disease is available at present. We describe the first case of a Chinese liver transplant recipient with PVB19-induced PRCA during immunosuppressive therapy. The patient suffered from progressive anemia with the lowest hemoglobin level of 21 g/L. Bone marrow biopsy showed selectively inhibited erythropoiesis with giant pronormoblasts. Detection of PVB19-DNA in serum with quantitative polymerase chain reaction （PCR） revealed a high level of viral load. After 2 courses of intravenous immunoglobulin （IVIG） therapy, bone marrow erythropoiesis recovered with his hemoglobin level increased to 123 g/L. He had a lowlevel PVB19 load for a 5-too follow-up period without recurrence of PRCA, and finally the virus was cleared. Our case indicates that clearance of PVB19 by IVIG in transplant recipients might be delayed after recovery of anemia.

Endotoxin receptor CD14 gene variants and histological features in chronic HCV infection

AIM:To analyze the correlation between CD14 rs2569190/C-159T single nucleotide polymorphism (SNP) and disease progression in chronic hepatitis C.METHODS: Liver biopsy specimens from a total of 137 and 349 patients with chronic hepatitis C were separately evaluated with respect to necroinflammatory activity (grading) and architectural changes (staging). In one group, further histological lesions characteristic for hepatitis C, hepatitis C virus subtypes, and biochemical parameters of liver disease were also investigated. Samples of genomic DNA were genotyped for the respective SNP by 5'-nuclease assays using fluorescent dye-labeled allele-specif ic probes.RESULTS: Genotype distribution did not deviate from the Hardy-Weinberg equilibrium. In the first group, patients homozygous for the variant allele T were found to be younger than C allele carriers (39.6±12.5 vs 45.7±11.5, P=0.008). Among the histological lesions studied, portal lymphoid aggregates were more frequently observed among TT homozygotes than among C carriers (21/37 vs 32/100, P=0.008). The presence of portal lymphoid aggregates was closely correlated with hepatic inflammation (P=0.003) and with bile duct damage (P<0.001). The degree of fibrosis, in contrast, was not found to be related to the CD14 gene C-159T polymorphism.CONCLUSION: The data suggest a possible relationship between CD14 C-159T polymorphism and the formation of portal lymphoid aggregates, but not liver fibrosis progression in chronic hepatitis C.

EFFECTS OF RADIX ANGELICAE SINENSIS AND SHUANGHUANGLIAN ON A RAT MODEL OF CHRONIC PSEUDOMONAS AERUGINOSA PNEUMONIA

Objective. To study the effects of two kinds of Chinese herbal medicine, Radix angelicae sinensis(RAS)(当归)and Shuanghuanglian(SHL)(双黄连) on chronic Pseudomonas aeruginosa(PA)lung infection in a rat model mimicking cystic fibrosis(CF). Methods.Rats were divided into RAS, SHL and control groups. All rats were challenged intratracheally with alginate embedded PA and the treatments with herbal medicine started on the same day of challenge. The drugs were administered subcutaneously once a day for ten days and the control group was treated with sterile saline.The rats were sacrificed two weeks after challenge. Results. Significantly improved lung bacterial clearance(P<005, P<001) and milder macroscopic lung pathology (P<0005) were found in the two treated groups compared to the control group. In the SHL treated group, the neutrophil percent in the peripheral blood leukocytes(P<005), the antiPA IgG level in serum (P<005), the incidence of lung abscesses(P<0005) and the incidence of acute lung inflammation(P<005) were significantly lower than in the control group. The RAS treatment reduced fever(P<005), decreased the incidence of lung abscesses(P<0005) and lung mast cell number (P<005), and lowered antiPA IgG1 level in serum(P<005) when compared to the control group. The antiPA bacterial activity test in SHL was weakly positive whereas in RAS it was negative. Conclusion.The treatment with both herbal medicines could increase the resistance of the rats against PA lung infection and they therefore might be potential promising drugs for stimulation of the immune system in CF patients with chronic PA lung infection.

Strategies for Antiviral Screening Targeting Early Steps of Virus Infection

Viral infection begins with the entry of the virus into the host target cell and initiates replication. For this reason, the virus entry machinery is an excellent target for antiviral therapeutics. In general, a virus life cycle includes several major steps: cell-surface attachment, entry, replication, assembly, and egress, while some viruses involve another stage called latency. The early steps of the virus life cycle include virus attachment, receptor binding, and entry. These steps involve the initial interactions between a virus and the host cell and thus are major determinants of the tropism of the virus infection, the nature of the virus replication, and the diseases resulting from the infection. Owing to the pathological importance of these early steps in the progress of viral infectious diseases, the development of inhibitors against these steps has been the focus of the pharmaceutical industry. In this review, Herpes Simplex Virus (HSV), Hepatitis C Virus (HCV), and Human Enterovirus 71 (EV71) were used as representatives of enveloped DNA, enveloped RNA, and non-enveloped viruses, respectively. The current mechanistic understanding of their attachment and entry, and the strategies for antagonist screenings are summarized herein.

New perspectives in occult hepatitis C virus infection

Occult hepatitis C virus (HCV) infection, defined as the presence of HCV RNA in liver and in peripheral blood mononuclear cells (PBMCs) in the absence of detectable viral RNA in serum by standard assays, can be found in anti-HCV positive patients with normal serum levels of liver enzymes and in anti-HCV negative patients with persistently elevated liver enzymes of unknown etiology. Occult HCV infection is distributed worldwide and all HCV genotypes seem to be involved in this infection. Occult hepatitis C has been found not only in anti-HCV positive subjects with normal values of liver enzymes or in chronic hepatitis of unknown origin but also in several groups at risk for HCV infection such as hemodialysis patients or family members of patients with occult HCV. This occult infection has been reported also in healthy populations without evidence of liver disease. Occult HCV infection seems to be less aggressive than chronic hepatitis C although patients affected by occult HCV may develop liver cirrhosis and even hepatocellular carcinoma. Thus, anti-HCV negative patients with occult HCV may benefit from antiviral therapy with pegylated-interferon plus ribavirin. The persistence of very low levels of HCV RNA in serum and in PBMCs, along with the maintenance of specific T-cell responses against HCV-antigens observed during a long-term follow-up of patients with occult hepatitis C, indicate that occult HCV is a persistent infection that is not spontaneously eradicated. This is an updated report on diagnosis, epidemiology and clinical implications of occult HCV with special emphasis on anti-HCV negative cases.

SCAR-PCR技术鉴定日本血吸虫尾蚴性别的应用

采用日本血吸虫单条毛蚴感染单个阴性钉螺的方法,培育获得可释放单一性别尾蚴的阳性钉螺。收集每只阳性钉螺释放的单一性别尾蚴,用序列特异扩增区域PCR(SCAR-PCR)鉴定尾蚴性别;用同一钉螺逸出的单一性别尾蚴感染小鼠后21 d,剖杀小鼠,收集成虫,判定成虫的性别以验证尾蚴性别(实验动物感染法)并评价SCAR-PCR鉴定单条尾蚴性别的正确性。结果显示,仅雌性尾蚴能扩增出153 bp的特异性条带,其鉴定结果与实验动物感染法的判定结果一致。SCAR-PCR检测DNA下限为16.5 ng,相当于1条尾蚴DNA量。采集经动物实验确认的雄性和雌性尾蚴各40条,应用SCAR-PCR检测出其中37条雌性尾蚴和40条雄性尾蚴。SCAR-PCR检测单条雌性尾蚴的正确性为92.5%(37/40),检测单条雄性尾蚴的正确性为100%(40/40)。应用SCAR-PCR可以鉴别日本血吸虫尾蚴的性别。

Design of an Optical Water Pollution Sensor Using a Single-Layer Guided-Mode Resonance Filter

The optical characteristics of a simple, planar, single layer, dielectric Mg-based guided mode resonance filter （GMRF） were investigated by means of rigorous-coupled wave analysis （RCWA）. This filter has great potential for real-life applications, especially as bio- and environmental sensors. The structure of the proposed sensor is compact, and all of its layers can be grown in a single process. In this paper, we present results on the design of a water pollution sensor in the violet region of the visible spectrum. The spectral and angular sensitivities of the sensor for both the transverse electric （TE） and transverse magnetic （TM） polarization modes were estimated and compared for various regions in the violet spectrum. A spectral response characterized with a narrow bandwidth and low reflection side bands was realized by carrying out extensive parameter search and optimization. Optimal spectral and angular sensitivities were found for the sensor with a grating thickness of 100nm in the TM polarized mode where we found them to be 100nm and 40 degrees, per index refraction unit, respectively.