Construction of a novel Shigella live-vector strain co-expressing CS3 and LTB/STm of enterotoxigenic E.coli

AIM: To construct and evaluate a polyvalent recombinant vaccine strain Shigella flexneri2a T32 against enterotoxigenic E.coli/(ETEC). METHODS: By using a host-plasmid balanced lethal system based on asd gene, a polyvalent recombinant strain was constructed to highly express CS3 and regularly express fusion enterotoxin of LIB subunit and mutant ST (LTB/STm) in a vaccine strain Shigella flexneri 2a T32 with specific deletion of asd gene. Fimbria CS3 was observed by immunofluorescence and electron microscopy assay. The security of LTB/STm was examined by ileal loop assay and suckling mouse assay. To evaluate this new candidate vaccine, it was compared with a previous vaccine strain in plasmid and protein level, growth assay and immunogenicity in Balb/c mice. RESULTS: The newly constructed vaccine expressed CS3 and grew better than the previously constructed vaccine except for the lower expression of LTB/STm. Serum IgG and mucosal IgA against CS3, LTB, ST, and host lipopolysaccharide (LPS) were produced after immunization of Balb/c mice by oral route with the new strain. The titers were not significantly different from the Balb/c mice with the previous strain. CONCLUSION: This novel candidate diarrheal vaccine can effectively induce serum and mucosal antibody responses against ETEC and Shigella.

Pharmacogenetics in inflammatory bowel disease

Pharmacogenetics is the study of the association between variability in drug response and （or） drug toxicity and polymorphisms in genes. The goal of this field of science is to adapt drugs to a patient＇s specific genetic background and therefore make them more efficacious and safe. In this article we describe the variants in genes that influence either the efficacy or toxicity of common drugs used in the treatment of inflammatory bowel diseases （IBD）, ulcerative colitis （UC）, and Crohn＇s disease （CD） including sulfasalazine and mesalazine, azathioprine （AZA） and 6-mercaptopurine （6-MP）, methotrexate （MTX）, glucocorticosteroids （CSs） and infliximab. Furthermore, difficulties with pharmacogenetic studies in general and more specifically in IBD are described. Although pharmacogenetics is a promising field that already contributed to a better understanding of some of the underlying mechanisms of action of drugs used in IBD, the only discovery translated until now into daily practice is the relation between thiopurine S-methyltransferase （TPMT） gene polymorphisms and hematological toxicity of thiopurine treatment. In the future it is necessary to organize studies in well characterized patient cohorts who have been uniformly treated and systematically evaluated in order to quantitate drug response more objectively. An effort should be made to collect genomic DNA from all patients enrolled in clinical drug trials after appropriate informed consent for pharmacogenetic studies.

Common toxicities and objective response rate in metastatic colorectal cancer patients treated with irinotecan based regimens

Objective： The aim of our study was to investigate if common toxicities are correlated to objective response rate （ORR） in metastatic colorectal cancer （mCRC） patients treated by irinotecan based regimens. Methods： Univadate and multivariate logistic regression analyses were performed to evaluate correlations between common toxicities and binary ORR in 106 mCRC patients from a prospective cohort treated with irinotecan based regimens. Results： The most frequent severe toxicities （Grade 3/4） were as follows： neutropenia （27.4%）, diarrhea （16.9%）, leucopenia （12.6%）, vomiting （3.2%） and thrombocytopenia （2.1%）. Thrombocytosis was observed in 25 （26.3%） patients. ORR was 25.3%. Thrombocytopenia （P = 0.014）, line of chemotherapy （P = 0.028） and thrembocytosis （P = 0.033） were correlated with ORR in univariate analysis. In multivariate analysis, thrombocytopenia （odds ratio [OR] = 8.600, 95% confidence interval [CI] = 1.705-43.385, P = 0.009） and first line chemotherapy （OR = 5.155, 95% CI = 1.153-23.256, P = 0.032） positively related to ORR. Conclusion： Threm- bocytopenia may be an indicator of ORR in mCRC patients treated by irinotecan plus 5-fluorouracil/capecitabine. Evidence is not strong enough to prove that irinotecan based regimens-induced diarrhea, leucopenia, neutropenia or vomiting is associ- ated with ORR.

Effect of Maternal Antibodies on the Pathogenesis of Avian Reovirus Infections in Broiler Chickens Using Real-Time Reverse Transcriptase Polymerase Chain Reaction

The effect of maternal antibodies on the pathogenesis of avian reovirus （ARV） was studied in commercial and specific pathogen free broilers （SPF） using a real-time reverse transcriptase （RT）-polymerase chain reaction （PCR） assay, along with the incidence and severity of morbidity, mortality, and gross lesions. ARV RNA was detected in cloacal swabs in both bird groups from the first day throughout the 21 days experiment. Commercial broiler chickens, which had high maternal antibodies against ARV, showed minimum clinical signs, gross lesions, and lower numbers of birds with viral RNA excretion, whereas specific pathogen free （SPF） broiler chickens, which did not have antibody against ARVs, had 30% mortality, more severe signs, and higher numbers of birds excreting viral RNA. The highest peak of SPF birds excreting viral RNA occurred during the time of maximum mortality. The protective effect of maternal antibody on ARV pathogenesis in broiler chickens correlated with the detection of ARV RNA using the real-time RT-PCR.