凤鸣藤茶的免疫毒理学评价

目的:观察凤鸣藤茶对小鼠免疫功能的影响。方法:将昆明种小鼠随机分为对照组、藤茶组(2.7 g/kg.bw.4.5 g/kg.bw.9 g/kg.bw 3个剂量组),喂养30 d,比较各组小鼠免疫功能改变情况。结果:与对照组比,藤茶组小鼠免疫器官脏体比,自然杀伤(NK)细胞活性、吞噬细胞功能显著增强,溶血空斑数明显增加,小鼠DTH肿胀度各组小鼠间差异无统计学意义。结论:凤鸣藤茶具有增强小鼠免疫功能的作用,免疫毒理学方面的评价是安全的。

T cell immunopathogenesis and immunotherapeutic strategies for chronic hepatitis B virus infection

Hepatitis B is caused by the host immune response and T cells play a major role in the immunopathogenesis. More importantly,T cells not only destroy hepatocytes infected by hepatitis B virus(HBV),but also control HBV replication or eradicate HBV in a noncytolytic manner.Therefore,analysis of T cell immune response during acute and chronic HBV infection is important to develop a strategy for successful viral control,which could lead to immunotherapy for terminating persistent HBV infection.There have been many attempts at immunotherapy for chronic HBV infection,and some have shown promising results.High viral load has been shown to suppress antiviral immune responses and immunoinhibitory signals have been recently elucidated, therefore,viral suppression by nucleos(t)ide analogs, stimulation of antiviral immune response,and suppression of the immunoinhibitory signals must be combined to achieve desirable antiviral effects.

Antiviral innate immunity pathways

Recent studies have uncovered two signaling pathways that activate the host innate immunity against viral infection. One of the pathways utilizes members of the Toll-like receptor （TLR） family to detect viruses that enter the endosome through endocytosis. The TLR pathway induces interferon production through several signaling proteins that ultimately lead to the activation of the transcription factors NF-kB, IRF3 and IRFT. The other antiviral pathway uses the RNA helicase RIG-Ⅰ as the receptor for intracellular viral double-stranded RNA. RIG-Ⅰ activates NF-kB and IRFs through the recently identified adaptor protein MAVS, a CARD domain containing protein that resides in the mitochondrial membrane. MAVS is essential for antiviral innate immunity, but it also serves as a target of Hepatitis C virus （HCV）, which employs a viral protease to cleave MAVS off the mitochondria, thereby allowing HCV to escape the host immune system.

Prolonged acute hepatitis A mimicking autoimmune hepatitis

AIM: We report a case with a prolonged course of hepatitis A, with alanine aminotransferase (ALT) higher than 500 IU/L for more than 2 mo. METHODS: A middle-aged woman had an elevated IgG level of more than 2 000 mg/dL, positive anti-nudear antibodies (ANA) and anti-smooth muscle antibodies (ASMA), but no evidence of persistent hepatitis A virus (HAV) infection. Liver biopsy findings were compatible with prolonged acute hepatitis, although acute onset of autoimmune hepatitis could not be ruled out. RESULTS: It was assumed that she developed a course of hepatitis similar to autoimmune hepatitis triggered by HAV infection. Ursodeoxycholic acid (UDCA) treatment was initiated and a favorable outcome was obtained. CONCLUSION: We describe a case of a middle-aged woman who showed a prolonged course of acute hepatitis A mimicking autoimmune hepatitis. Treatment with UDCA proved to be effective.

Serum-free culture of H pylori intensifies cytotoxicity

AIM： To perform a long culture passage of H pylori without serum, taking into account its cytotoxicity and the presence of the probable new cytotoxic factor. METHODS： One sample of H pylon 60190 （ATCC 49503） was grown on Brain Heart Infusion （BHI） agar containing 0.5% 2,6-di-O-methyl-β-cyclodextrin without any serum, being passaged 70-100 times every 3-4 d for approximately 2 h, while another sample of H pylori contained 70 mL/L fetal calf serum without 2,6-di-O- methyl-β-cyclodextrin. Their supernatant and extract after 16 h in culture were evaluated for changes in cell morphology and for cell viability using HeLa cells. Furthermore, the characteristics of the probable cytotoxic factor in the extract were examined on partial purification studies and its oytotoxicity was evaluated in various human cells. RESULTS： The supernatant and the extract of the bacterium grown on serum-free medium had strong cytotoxicity compared with those grown on serumcontaining medium. They irreversibly damaged HeLa cells without vacuolation that was altogether different from that of the bacterium when grown with serum. Their cytotoxicity was easily measured by cell viability assay. The probable cytotoxic factor partially purified and detected by chromatography had characteristics difference from that of vacuolating toxin and a broad cytotoxicity toward various cell lines. CONCLUSION： Serum-free long culture method of H pylorl makes its supernatant and its extract cytotoxic enough to be easily measured by cell viability assay. The probable cytotoxic factor has a unique characteristic and might be a new cytotoxin.

Plasmablastic lymphoma of the small intestine:Case report and literature review

Plasmablastic lymphoma(PBL) is a rare aggressive B-cell lymphoproliferative disorder,which has been characterized by the World Health Organization as a new entity.Although PBL is most commonly seen in the oral cavity of human immunodeficiency virus(HIV)-positive patients,it can also be seen in extraoral sites in immunocompromised patients who are HIV-negative.Here we present a rare case of PBL of the small intestine in a 55-year-old HIV-negative male.Histopathological examination of the excisional lesion showed a large cell lymphoma with plasmacytic differentiation diffusely infiltrating the small intestine and involving the surrounding organs.The neoplastic cells were diffusely positive for CD79a,CD138 and CD10 and partly positive for CD38 and epithelial membrane antigen.Approximately 80% of the tumor cells were positive for Ki-67.A monoclonal rearrangement of the kappa light chain gene was demonstrated.The patient died approximately 1.5 mo after diagnosis in spite of receiving two courses of the CHOP chemotherapy regimen.In a review of the literature,this is the first case report of PBL with initial presentation in the small intestine without HIV and Epstein-Barr virus infection,and a history of hepatitis B virus infection and radiotherapy probably led to the iatrogenic immunocompromised state.

Cytomegalovirus-associated colitis causing diarrhea in an immunocompetent patient

Cytomegalovirus （CMV） colitis rarely occurs in immunocompetent patients. We report a case of disabling and life threatening diarrhea in an immunocompetent elderly woman due to CMV colitis. The diagnosis of CMV was based on histological examination of tissues biopsied at colonoscopy, positive CMV antigen and high CMV-lgM titer in peripheral blood samples and a good response to systemic gancyclovir treatment. We conclude that CMV should be considered in the differential diagnosis of colitis in elderly immunocompetent patients.

Epidemiological and pathogenic study on the outbreak of toxic shock syndrome and meningocephalitis caused by swine streptococcus

Objective: To reveal the relationship between the biological characteristics of pathogen and the pig to human spread of the epidemic and infectious disease in 1998 in East China. Methods: Epidemiological survey, pathological examination of pigs and patients, and pathogen isolation were performed. Results: The disease had a character of quick onset, serious symptoms, short course and high mortality. The clinical manifestations and pathological changes of the disease were high fever, sometimes with nausea, vomiting and diarrhea, then might develop to myositis, fascitis, DIC, multiple organ failure, shock and usually died in 2 3 d. Among 25 patients, 16 manifested clinically as streptococcal toxic shock syndromes and 9 streptococcal meningiocephalitis syndrome. The mortality was 81 25% and 11 11% respectively. Pathogenic bacteria isolated from diseased pigs and patients were found to have some common characteristics in morphology, staining and biological characters. Conclusion: The pathogen isolated from the blood of patients and pigs were identified as streptococci.

The in vitro inhibitory effect of human neutrophil peptide-1 on human immunodeficiency virus type 1

In order to clarify, the mechanism of inhibition of human neutrophil peptide-1 （ HNP-1 ） on hu- man immunodeficiency vires type 1 （HIV-1 ）, CD4^ ＋ cells were used as the target cells for acute infection with HIV-1, and experiments were peffomed separately with the interaction of different concentrations of HNP-1 with free vires particles, un-infected and infected CD4^＋ cells. The activity of reverse transcriptase （RT） in the supematant of cell cultures of different lots of experiments were then assayed accordingly, and the toxicity effect on human lymphocytic cells MT4 was measured by MTT assay. The experimental results showed that pre-incubation of HNP-1 with the concentrated stock of vires could block the binding of vires to target cells with EC50 of 2.49 μg/ml, while pre-treatment of CD4^＋ cells with HNP- 1 prior to inoculation could reduce the ability of cells to bind vires with EC50 of 20.7 μg/ml. In addition, When culturing the infected CD4^＋ cells in the continuous presence of various concentrations of HNP-1 added immediately after infection, HNP-1 exhibited modest inhibitory effect on viral replication with reduced RT activities in comparison with those of the control group （ P 〈 0.05 at 100 μg/ml of the highest concentration） . No cytotoxieity effect of HNP-1 was observed as demonstrated by MTT assay. These results indicate that HNP-1 exerts anti-HIV activity by at least two levels： direct inactivation of vires particles and effect on the ability of target cells to bind with viruses. The evaluation of two parameters, inhibitoty effect and the cytotoxicity renders HNP-1 an available candidate for anti-HIV therapeutic agent.

Experiments that led to the first gene-edited babies: the ethical failings and the urgent need for better governance

The rapid developments of science and technology in China over recent decades, particularly in biomedical research, have brought forward serious challenges regarding ethical governance. Recently, Jian-kui HE, a Chinese scientist, claimed to have "created" the first gene-edited babies, designed to be naturally immune to the human immunodeficiency virus(HIV). The news immediately triggered widespread criticism, denouncement, and debate over the scientific and ethical legitimacy of HE’s genetic experiments. China’s guidelines and regulations have banned germline genome editing on human embryos for clinical use because of scientific and ethical concerns, in accordance with the international consensus. HE’s human experimentation has not only violated these Chinese regulations, but also breached other ethical and regulatory norms. These include questionable scientific value, unreasonable risk-benefit ratio, illegitimate ethics review, invalid informed consent, and regulatory misconduct. This series of ethical failings of HE and his team reveal the institutional failure of the current ethics governance system which largely depends on scientist’s self-regulation. The incident highlights the need for urgent improvement of ethics governance at all levels, the enforcement of technical and ethical guidelines, and the establishment of laws relating to such bioethical issues.