Polyamines in Trichomonas vaginalis

Trichomonas vaginalis was grown in a modified Bushby's medium and putrescine, spermidine and spermine levels were determined in extracts from 24- and 48-h cultures and also in the culture media. All three polyamines were present in T. vaginalis extracts; the putrescine level and putrescine/spermidine ratio were much higher than those reported for other protozoa or for mammalian tissues. There were no significant differences between 24-h and 48-h amine levels per mg protein in these extracts, but amine levels per cell were higher at 24 than at 48 h. The spent culture media had a much higher putrescine content than corresponding uninoculated media and it was concluded that T. vaginalis secreted putrescine into the culture medium.     

Hemagglutination by Staphylococcus aureus strains responsible for human bacteremia or bovine mastitis

Although hemagglutination by Staphylococcus aureus has been associated with the pathogenesis of bovine mastitis, this trait has not been characterized with regard to human disease. In this study, the prevalence of hemagglutination in 100 strains of S. aureus responsible for bovine mastitis or human bacteremia, was characterized. Under optimum conditions hemagglutination was noted in 23% of the bovine strains, but only 13% of human strains, leading us to conclude that this trait is not a significant virulence determinant in human systemic infection. Additional studies indicate the hemagglutinin of S. aureus strains responsible for human bacteremia is proteinaceous in character.     

Correlation between soluble serum CD16 (sCD16) levels and disease stage in patients with multiple myeloma

CD16, the type III receptor for IgG, is expressed on neutrophils, natural killer cells, and some T lymphocytes, mast cells, and activated monocytes but not on cells of the B-lymphocyte lineage including plasma cells. It is also produced in a soluble form found in serum. We analyzed sera from 165 multiple-myeloma patients, 29 patients with monoclonal gammopathies of unknown significance, and 20 normal disease-free donors. We found that the level of soluble CD16 was significantly decreased in sera from patients with multiple myeloma compared to sera from healthy and monoclonal gammopathies of unknown significance donors (P=0.0001). In addition, a stage-dependent decrease in soluble CD16 was observed, with a highly significant difference (P=0.004) between stage I and stage II+III myeloma patients. The correlation between the myeloma stage and the serum level of soluble CD16, which is related to the host response, was found to be more sensitive than that of ₂-microglobulin, which reflects the tumor burden. The concomitant evaluation of the serum levels of these two markers allows better staging and therefore has a more precise prognostic value.     

The laminar organization of dorsal horn cells responding to peripheral C fibre stimulation

Summary Cat dorsal horn was searched for all detectable units that responded to peripheral C fibre input. Fifty-seven such units were examined in detail. They were located in two main areas. One group was in the superficial laminae 1, 2, and possibly dorsal 3 (n = 29), and the other group was much deeper in laminae 5 and 6 (n = 24). Only four units were situated in the region of lamina 4.Differences were found in the responses to C fibre stimulation of these two groups, both in the optimum stimulus and in the timing of responses to repeated stimulation. Superficial units often did not respond to C fibre stimulation unless a train of two or more stimuli (10 ms apart) were applied, but when responses did occur they were usually very even and regular, with precise onset latencies on repeated stimulation. Deep units tended to need only one peripheral C fibre stimulus for excitation, but the responses were irregular with latencies fluctuating with each stimulus. Some superficial and deep units showed a steady increase in latency of the late C response on repeated stimulation. Increases of up to 80 ms after 30 s of stimulation at 1 Hz were observed.The results are discussed in terms of the neuronal connections in the dorsal horn.The work was supported by the Medical Research Council and the National Institutes of HealthM. Fitzgerald is a Medical Research Council Training Fellow     

Peripheral blood mononuclear cell proliferative responses to soluble and particulate heat shock protein 65 in health and inflammatory bowel disease

Objectives: The aims of this study were to determine, in peripheral blood mononuclear cells (PBMC), whether particulate antigen triggers (i) an amplified cell proliferative response compared to soluble antigen and (ii) a dysfunctional response in cells derived from patients with chronic inflammation and specifically in those with inflammatory bowel disease (IBD). Subjects: Healthy volunteers (n = 17), inflammatory controls (n = 8) and patients with IBD (n = 17) were recruited from St Thomas’ and Guys’ Hospital, London, UK. Methods: Following optimisation of experimental conditions (0.1–10.0 μg/ml antigen), PBMC were stimulated with (i) 10.0 μg/ml recombinant soluble heat shock protein 65 (hsp 65) and (ii) 1.0 and 10.0 μg/ml hsp 65 conjugated to microparticles (0.5 μm diameter). PBMC proliferative responses were measured by ³H-Thymidine incorporation at day 5 and results compared between groups using unpaired t-test. Results: Conjugation to microparticles of low dose hsp 65 significantly increased overall proliferative responses by 2–11 fold compared to soluble antigen alone (p < 0.05). However, no specific PBMC proliferative dysregulation was noted in cells from subjects with IBD. Conclusions: Low dose antigen, in microparticulate form, leads to amplified cell proliferation in primary human cells, as showed previously in cell lines and animal studies. However there is no abnormal proliferative response in cells from subjects with IBD. Received 8 February 2006; returned for revision 7 March 2006; accepted by G. Wallace 25 October 2006     

血清淀粉样P成分的DNA结合特性

目的 检测血清淀粉样P成分(SAP)与不同DNA的结合活性并研究SAP与DNA的结合是否有利于此类抗原的清除，探讨它在SLE发生发展中的作用及意义。方法 用亲和层析和凝胶过滤方法自小鼠和人血清中纯化SAP，分别提取来自细菌、质粒、酵母、小鼠淋巴细胞等不同DNA，用DOT-EIA方法检测SAP与它们的结合活性，用巨噬细胞吞噬实验观察SAP与DNA结合后对DNA清除的影响。结果 人和小鼠SAP均与细菌DNA结合最强，其次为质粒、酵母DNA，与淋巴细胞DNA和小牛胸腺DNA的结合较弱，与单链λDNA结合最弱；与来源于活化状态小鼠淋巴细胞DNA的结合力高于非活化状态；SAP与活化淋巴细胞DNA结合后可促进巨噬细胞对DNA的吞噬。结论 SAP与不同DNA结合活性各异。     

成年大鼠胰岛的体外基因转染

目的 探讨携带外源基因的慢病毒在体外有效感染胰岛及外源基因在胰岛中的表达，为通过移植前向胰岛细胞转入特定的免疫调节分子基因诱导胰岛移植物耐受奠定基础。方法 将目的基因CTLA4Ig导入慢病毒载体pWPTS，构建成pWPTS-CTLA4Ig载体。用磷酸钙沉淀法将pWPTS-EGFP、pWPTS-CTLA4Ig分别和其辅助载体pMD2．G、pCMVΔ8．92共转染293T细胞，收获病毒上清液，测定病毒滴度后感染新分离的胰岛。通过Western Blot测定胰岛培养上清液中CTLA4Ig蛋白的表达。结果 ①成功构建了携带CTLA4Ig基因的慢病毒载体pWPTS-CTLA4Ig；②包装产生的慢病毒Lenti-EGFP、Lenti-CTLA4Ig在体外可以感染胰岛，其中在Lenti-EGFP慢病毒感染的胰岛观察到了绿色荧光，及在Lenti-CTLA4Ig慢病毒感染的胰岛培养上清液中检测到了CTLA4Ig蛋白的表达。结论 慢病毒在体外可以有效感染大鼠胰岛，且携带的外源基因可以在胰岛细胞中稳定表达，其中Lenti-CTLA4Ig慢病毒感染的胰岛为进行胰岛移植并诱导体内特异的胰岛移植物耐受奠定了基础。     

建立一种用重组蛋白检测抗口蹄疫病毒抗体的间接ELISA方法

目的研究以重组蛋白作为包被抗原检测口蹄疫病毒（FMDV）感染后的动物血清中特异性抗体的可能性,为建立一种非病毒颗粒的ELISA检测试剂盒提供实验依据。方法利用自行构建表达的O型口蹄疫病毒VP1表位肽重组蛋白（VP1epi）作为包被抗原,采用间接ELISA方法确定抗原的最佳工作浓度和包被方法,优化各项实验条件,并以FMDV感染后的豚鼠血清作为标准阳性血清确定ELISA方法的特异性和灵敏度。结果FMDV感染后的阳性豚鼠血清可以很好地识别VP1epi重组蛋白,用此蛋白包被检测抗FMDV抗体的灵敏度可达1∶3200,并证明所检测的抗体是FMDV特异性的。结论VP1epi重组蛋白可以替代FMDV颗粒用于建立检测抗FMDV抗体的ELISA试剂盒。