Unter welchen Voraussetzungen sind Cryptococcus neoformans var. neoformans‐Stämme aus Vogelexkrementen als Ursache menschlicher Infektionen anzusehen?

Detection of antigen factors of Cryptococcus with factor sera in slide agglutination confirms diagnosis of species and varieties of Cryptococcus neoformans (Cr. n). This method is important in investigations of sources of infections. Serotype D strains of Cr. neoformans were detected in pigeon breedings from Thuringia exclusively. Because of that an essential difference exists in comparison to human isolates in Germany and strains from breeding stocks of companion birds in Thuringia where serotype A strains are predominant in pet birds and in human infections. Using different primers in PCR fingerprinting Cr. neoformans isolates can be assigned to serotypes A, B, C and D and to varieties Cr. neoformans neoformans and Cr. neoformans gattii (primer FM 1). On the other hand, genetic heterogeneity of Cr. neoformans strains is detectable within the serotypes A and D (primer 60-26). This genetic heterogeneity can be demonstrated in investigations by Fourier Transform Infrared (FTIR) spectroscopy, too. Isolated Cr. neoformans strains from pigeons (serotype D) could be divided into 3 and from pet birds (serotype A) into 2 different clusters by FTIR spectroscopy. It is important to take into account heterogeneity of strains within serotypes for determination of infection chains of human disease.     

半夏茯苓胶囊对化疗呕吐家鸽胃肠激素影响的实验研究

目的:对半夏茯苓胶囊抗化疗呕吐的内在机制加以探讨。方法:采用家鸽翼下静脉注射顺铂法制造呕吐模型,用放射免疫法测定外周血中的胃肠激素。结果:与水煎剂一样,半夏茯苓胶囊高剂量组能明显升高外周血中胃动素(MTL)的含量(P<0.05),同时可明显降低外周血中血管活性肠肽(VIP)和胃泌素(GAS)的含量(P<0.05)。结论:半夏茯苓胶囊(BFC)可能具有减少化疗对胃肠黏膜的损害,增加胃肠蠕动和加快胃排空的作用,其正性的胃肠活动可能参与了止吐,这可能是该药抗化疗呕吐的机制所在之一。     

连苏止呕胶囊对化疗呕吐家鸽胃肠激素和神经递质的影响

目的　探讨连苏止呕胶囊抗化疗呕吐的内在机制。方法　采用家鸽腹腔注射顺铂法制造模型 ,用放免试剂盒检测胃肠激素 ;用高效液相色谱 电化学检测法检测神经递质。结果　连苏止呕胶囊高剂量组能升高外周血中表皮生长因子 (EGF)的含量 (P <0 0 5 ) ,连苏止呕胶囊低剂量、高剂量组能降低外周血中胃泌素 (Gas)的含量 (P <0 0 5 ,P <0 0 1)。脑干中连苏止呕胶囊高、低剂量组 5 羟色胺 (5 HT)、多巴胺 (DA)的含量变化均与模型组差异有统计学意义 (P <0 0 5 ,P <0 0 1)。结论　连苏止呕胶囊对胃肠黏膜起到了一定的保护作用 ,对胃肠运动具有改善作用。它可能既是 5 HT受体拮抗剂 ,又是DA受体拮抗剂 ,而且作用较强。     

Effect of cigarette smoking on the humoral immune response in pigeon fanciers

Tobacco smoking is associated with increased prevalence of various diseases. In this study, we have used an indirect enzyme-linked immunosorbent assay (ELISA) to investigate the specific IgG response to pigeon serum and its relationship to tobacco smoking. In a large group of pigeon fanciers the development of pigeon breeder's disease and some of the clinical features were also investigated. We found a sensitization rate of 31.9%, a lower degree than that found by other authors, in spite of using a less specific antigen. We also found that fanciers who are current cigarette smokers had significantly lower levels of IgG antibody to pigeon serum (P less than 0.001). Finally, 11.9% of the population had chronic bronchitis as their only manifestation of possible pigeon-related disease. 19.6% of the sensitized fanciers had chronic bronchitis, were non-smokers and had no other risk factor for developing chronic bronchitis.     

Immunoregulation in hypersensitivity pneumonitis. I. Differences in T-cell and macrophage suppressor activity in symptomatic and asymptomatic pigeon breeders

Cell-mediated immunity delineates symptomatic from asymptomatic pigeon breeders better than the presence of precipitating antibodies or HLA haptotypes. We therefore investigatedin vitro lymphocyte function in asymptomatic and symptomatic pigeon breeders. Peripheral blood, T, B, and adherent numbers were equal in both groups. Although the response to an optimum dose of concanavalin A was similar in both groups, the asymptomatic group revealed a reduced response to an optimum concentration of phytohemagglutinin and pokeweed mitogen. This decreased mitogen-induced proliferation was abrogated if cells from asymptomatic patients were precultured in medium alone for 48 hr before stimulation. A similar preincubation procedure, however, decreased the response to subsequent mitogenic stimulation in the symptomatic patients. As this suggested the possibility of heightened immunosuppression in the asymptomatic group, suppressor cells were studied. The numbers of FC-bearing T cells were similar in both groups and did not differ from control values. In addition, concanavalin A-induced suppressor-cell activity did not differ in either group. Nonetheless, fresh T cells, adherent cells, and peripheral blood mononuclear cells (PBMC) preincubated with pigeon serum decreased the response of preincubated autologous PBMC to mitogens and antigens in asymptomatics. A similar suppression did not occur in autoch-thonous cocultures of PBMC from symptomatic patients. These data suggest that there may be cellular suppressor influences in the asymptomatic group which are absent or nonfunctional in the symptomatic patients. Although this may be useful in distinguishing between the groups, the relationship of these suppressor cells, if any, to the pathogenesis of hypersensitivity pneumonitis awaits further study.     

Pigeon circoviruses from feral pigeons in Australia demonstrate extensive recombination and genetic admixture with other circoviruses

ABSTRACT

Like other avian circovirus species, Pigeon circovirus (PiCV) is known to be genetically diverse with a relatively small circular single-stranded DNA genome of 2?kb that encodes for a capsid protein (Cap) and a replication initiator protein (Rep). Recent paleoviral evidence hints towards a probable Gondwanan origin of avian circoviruses, paralleling the evolution and dispersal of their hosts. Limited availability of PiCV genome sequence data in Australia has hindered phylogeographic studies in this species, so we screened clinically normal rock doves (Columba livia) in regional New South Wales, and demonstrated a high prevalence (76%) of PiCV infection by PCR. We also recovered 12 complete novel PiCV genomes and phylogenetic analyses revealed that PiCV circulating in Australian feral pigeons formed two strongly supported monophyletic clades. One clade resided with PiCV genomes from Poland, Australia, United Kingdom, Belgium, China, and Japan, and another basal clade was more closely related to PiCV genomes from Poland. A novel more distantly-related PiCV rep gene formed a solitary clade with weak posterior support. So we further analysed all selected partial rep gene sequences to demonstrate a likely naturally occurring spillover infection from a passerine circovirus candidate. The findings suggest that there is a high degree of genetic variation within PiCV in Columbiformes with potential greater admixture between avian circoviruses within Australia than previously known.

RESEARCH HIGHLIGHTS

• Confirmed high prevalence rate of PiCV circulating in Australian wild pigeons.

• Highlighted extensive recombination events within Australian PiCV.

• Demonstrated a likely naturally occurring spillover infection from a passerine circovirus candidate.

     

两种新型隐球菌选择性培养基的比较研究

目的比较咖啡酸玉米琼脂培养基(caffeic acid cornmeal agar medium,CACA)和黑米琼脂培养基(black rice agar medium)对鸽粪中新型隐球菌的分离效果。方法用无菌竹签从鸽舍随机采取鸽粪标本,取0.6g与10ml无菌生理盐水制成悬液,然后按每个平板100μl分别接种咖啡酸玉米琼脂培养基和黑米琼脂培养基,肉眼观察菌落形态、颜色,光学显微镜下观察菌体形态,同时用特异性引物CN4和CN5扩增新型隐球菌URA基因,分别统计两种培养基中出现阳性菌株的平板数目。结果黑米琼脂培养基中新型隐球菌菌落呈棕黄色,外观湿润,状似胶汁。共分离获得23株新型隐球菌,检出率32.86%。CACA中新型隐球菌菌落较黑米琼脂培养基上的菌落小,褐色,干燥。共分离出11株新型隐球菌,检出率为15.71%。黑米琼脂培养基的检出率与CACA比较差异有统计学意义(P<0.05),且丝状真菌覆盖性生长的平板数目少于CACA,污染程度低于CACA;通过墨汁染色,在光学显微镜下观察新型隐球菌菌体呈圆形或卵圆形,外有宽厚荚膜,PCR扩增得到了目的条带产物。结论黑米琼脂培养基作为新型隐球菌的选择性培养基其分离培养效果(检出效果和检出率)优于CACA。     

Immunoglobulin and antibody levels in bronchoalveolar lavage fluid from symptomatic and asymptomatic pigeon breeders.

Twenty-one symptomatic subjects with pigeon breeders' lung (PBL) and 10 asymptomatic pigeon breeders, with a similar exposure to pigeon antigens, underwent bronchoalveolar lavage. Total IgG, IgM and IgA in lavage fluid were determined as were specific antibody levels against antigens in pigeon serum and droppings. Results were converted to levels in epithelial lining fluid (ELF) using lavage and serum urea ratios. It was found that symptomatics represent a group that is hyperreactive to pigeon antigens compared with the asymptomatic group with significantly higher IgG, IgM, IgA levels as well as specific antibody levels against pigeon serum and droppings. Paired serum and ELF samples from 12 symptomatic subjects showed significantly elevated IgG, IgM and IgA levels in ELF compared with serum when values were expressed in terms of albumin. This strongly supports the concept of local production of immunoglobulins within the lung after inhaling immunogens as opposed to their diffusion from the vasculature. Results for IgA indicate that any putative protective role for this immunoglobulin is not valid in relation to the prevention of extrinsic allergic alveolitis. Analysis of smoking habits, lung immunoglobulins and response to inhalation challenge confirm the negative influence of smoking on total and functional lung immunoglobulins; however, levels in the ELF of ex-smokers suggest that the effect of smoking is not permanent. Smoking did not prevent responses to inhalation challenge.