肺炎支原体感染大鼠实验模型的建立

本试验旨在建立肺炎支原体感染的Wistar大鼠模型 ,为研究肺炎支原体的发病机制及药物治疗理论提供基础。采用滴鼻法对实验大鼠进行肺炎支原体感染 ,利用PCR法进行咽拭子检测 ,并以透射电镜和光学显微镜进行肺部病理组织学检查。结果发现 ,实验大鼠在感染肺炎支原体 1 0d时 ,咽拭子PCR检测结果为阳性 ;透射电镜观察到肺脏细胞膜破裂 ,线粒体变性 ,嵴断裂 ;光镜下可见到支气管及肺血管周围有明显的淋巴细胞浸润 ,形成斑片状间质性支气管肺炎。结果表明了Wistar大鼠对肺炎支原体较易感 ,并产生以间质性肺炎为主要特征的肺部和呼吸道感染 ,也说明本次造模试验成功     

猪肺炎霉形体对培养基中的新生仔猪气管环纤毛的损害作用

据报导,猪肺炎霉形体对猪气管粘膜纤毛有损害作用,将猪肺炎霉形体接种于猪胚气管环和肺单层细胞上培养,它能使上皮细胞纤毛损害脱落;将接种猪肺炎霉形体无菌猪的气管和支气管作电镜扫描,观察到霉形体的早期感染存在于纤毛上皮细胞,在气管     

猪肺炎支原体对养猪生产的危害及防治

目前 ,许多大型猪场都遭受着越来越严重的呼吸道疾病的困扰 ,而猪肺炎支原体是引起猪呼吸道疾病的主要元凶。研究表明 ,猪肺炎支原体主要存在于猪气管及支气管中 ,使气管和支气管的纤毛上皮细胞发生病变或坏死 ,甚至破坏呼吸道粘膜层 ,使纤毛发生萎缩或脱落 ,从而失去清除气源性病原体、有害微粒及正常肺液的作用。猪肺炎支原体还可抑制机体免疫应答 ,感染了肺炎支原体的猪 ,其巨噬细胞的功能会发生改变 ,对蓝耳病和多杀性巴氏杆菌病等易感性更高。所以在生产实践中几乎所有发生支原体肺炎的猪都有不同程度的继发感染。其中 ,蓝耳病、多杀性…     

猪肺炎支原体对养猪生产的危害及防治

目前,许多大猪场(大型现代化猪场,著名种猪场,外贸猪场等也不例外)都遭受着越来越严重的呼吸道疾病的困扰,而猪肺炎支原体是引起这类疾病的主要元凶。据统计,感染了猪支原体肺炎的猪群,生长缓慢(严重的还会发生死亡),其饲料利用率平均下降8%～10%,出栏也会因此延迟10～15d(以100kg体重为上市标准),极大地影响了养猪生产的经济效益。1致病机理研究表明,猪肺炎支原体主要存在于猪气管及支气管中,使气管和支气管的纤毛上皮细胞发生病变或坏死,甚至破坏呼吸道粘膜层,使纤毛发生萎缩或脱落,从而失去清除气源性病原体、有害微粒及正常肺液的作用。…     

猪喘气病防控策略及方案

猪喘气病是由猪肺炎支原体引起的一种疾病,该病在猪场较为普遍。猪肺炎支原体感染猪后主要侵害气管和支气管黏膜层的纤毛,导致部分纤毛功能受损或脱落。因此肺炎支原体被认为是打开肺脏其他病原感染门户的主要病原体。如果继发其他病原感染,引发的肺炎会比较复杂且对猪的损伤更加严重。因此控制好肺炎支原体,对于其他呼吸道疾病的防控有着重要的作用。下面笔者结合肺炎支原体的一些流行病学特点针对性地谈谈对其防控策略及方案。     

山羊支原体肺炎的CT影像分析

旨在研究羊感染肺炎支原体后胸部CT影像学特征。将20只山羊分为2组,对照组5只、试验组15只,试验组通过气管注射感染5 mL绵羊肺炎支原体（1×10⁷ CCU·mL^-1）人工诱发山羊支原体肺炎,对照组注射等体积生理盐水。感染后观察两组羊的临床症状,在感染后第0、7、14、21、28天对两组羊胸部进行CT扫查,分析支原体肺炎的CT影像学特征。感染后第29天剖杀羊,观察肺部病理解剖变化。取病变组织制备石蜡切片,观察组织病理学变化。结果显示：试验组山羊感染肺炎支原体后表现出呼吸道感染症状,体温升高,咳嗽,流浆液性或脓性鼻液。胸部CT影像主要表现为片状磨玻璃密度影,网格状阴影,多见双侧肺叶病变,好发于右前叶,以间质性肺炎伴发支气管肺炎为主,其中,重症羊多见空气支气管征,个别羊见胸膜增厚影。对照组临床症状和胸部CT影像在感染前后未见明显差异和异常。综上表明,CT影像诊断技术有利于羊支原体肺炎的早期诊断,并有助于疾病转归的判断。     

鸡毒支原体的感染特征有哪些?

正鸡毒支原体主要在气管粘膜的纤毛上和气囊上定植,而气管纤毛末端和气囊上没有血管,而药物是通过血液运输到达作用部位,再通过扩散作用于毒支原体,因此药物只能减少气管纤毛和气囊上定植的毒支原体数量和减轻临床症状,而不能完将其杀灭,因此鸡毒支原体感染一般为一次感染会终生处于持续性感染的带菌状态,当鸡群处于应激状态,如     

芩黄清肺散的药效学研究

为了观察中药复方制剂芩黄清肺散的抗炎、止咳、化痰、平喘作用,试验将动物随机分为模型组、阳性药物组、芩黄清肺散高、中、低剂量组。通过二甲苯致小鼠耳廓肿胀模型法观察芩黄清肺散抗炎作用;通过小鼠浓氨水引咳法观察其止咳作用;通过小鼠气管酚红排泌法观察其祛痰作用;通过组织胺和乙酰胆碱豚鼠引喘模型观察其平喘作用。结果表明:芩黄清肺散能够降低二甲苯所致小鼠耳部肿胀,提高抑制率;能显著抑制浓氨水引起的咳嗽,延长咳嗽潜伏期,减少咳嗽次数;能促进小鼠气管内酚红的分泌,促进痰液的排出;哮喘试验中芩黄清肺散能延长豚鼠哮喘发作潜伏期。可见芩黄清肺散具有较好的止咳、祛痰、平喘、抗炎作用。     

摩托车尾气对小鼠呼吸系统组织结构的影响

60只昆明种雄性小鼠随机分为3组,A组(对照组)、B组(用普通摩托车尾气染毒)和C组(用微型摩托车尾气染毒),染毒4周后处死,取出气管、肺脏制作组织切片观察其组织结构.结果表明,试验组小鼠的气管组织结构变得疏松,软骨组织和黏膜下层出现萎缩现象,尤其是C组的气管上皮出现化生,即由假复层纤毛柱状上皮变成鳞状上皮;试验组小鼠肺的各级支气管出现黏膜上皮细胞萎缩、纤毛脱落等现象,肺泡管、肺泡囊及肺泡也发生了一定程度的破坏,尤其是C组肺内小动脉出现管壁增厚、管腔狭窄等现象.     

猪支原体肺炎研究进展

猪支原体肺炎由猪肺炎支原体(Mycoplasma hyopneumoniae)所引起,呈现一种轻微的肺炎症状,除非有应激因素使猪的病势加重,否则不易看出。但是猪的增重率和饲料换算率减低,并因支原体肺炎使机体衰弱,容易感染其他疾病。支原体缺乏细胞壁,它侵占肺细胞间隙,以寄主蛋白质包裸自己。因而猪体不把它当作一个侵袭者,也不明显地试图去中和它。气管、支气管的毛发样纤毛,保护身体,抵抗外界侵袭物,而支原体能破坏并阻止纤毛运动。     

Pathological changes of tracheal mucosa in chickens infected with infectious laryngotracheitis virus

Six-week-old chickens were inoculated via the posterior thoracic air sac with infectious laryngotracheitis virus. Chickens were sacrificed on various days through day 16 postinoculation (PI), and the trachea was examined by scanning electron microscopy (SEM) and light microscopy (LM). The pathological changes observed on day 1 PI were hypertrophy and hyperplasia of goblet cells. From day 3 PI, the epithelial cells protruded collectively and fused to form syncytia, which contained many intranuclear inclusion bodies. Subsequently, epithelial syncytia desquamated, one after another, and connective tissues were exposed in places. Serofibrinous exudate and detritus were abundant on the surface of the exposed connective tissues and seemed to form a pseudomembrane. On day 5 PI, the remaining epithelial cells began to repair the devastated mucosa just under the pseudomembrane. On day 6 PI, microvillus-rich regenerating epithelial cells were arranged like paving stones. On day 8 PI, the epithelial cells proliferated extensively and formed folds with cyst-like structures. By day 16 PI, the tracheal epithelium was covered with cilia and regained its normal histologic appearance.     

鸡败血霉形体致鸡胚气管器官培养病变观察

将３株鸡败血霉形体（ＭＧ）菌株的培养特,分别感染离体培养的鸡胚气管环。经光学显微镜观察,发现３个菌株均具有致纤毛运动停止的作用。扫描电镜观察,在接种ＭＧ的气管环上,见到明显的纤毛脱落、细胞剥离、粘膜面凹陷等上皮受侵蚀变化,同时见霉形体附着于光秃的上皮表面或残存纤毛的顶端。在未接种ＭＧ的气管环上未见此等现象。     

Electron microscopic observation of the respiratory tract of SPF piglets inoculated with Mycoplasma hyopneumoniae.

Seven hysterectomy derived piglets were repeatedly challenged with Mycoplasma hyoneumoniae during the first week of life. Samples of trachea, bronchi and lung tissue collected 2–11 weeks post-inoculation (p.i.) were examined using light and electron microscopy. Autoradiography was used to study in more detail the site of M. hyopneumoniae multiplication. Gross lesions were observed in lung tissue and were characterized by hyperplasia of the epithelium and an increased mononuclear cell accumulation in perivascular and peribronchiolar areas. Mild lesions of the trachea and the bronchi, including epithelial hyperplasia and infiltration of the lamina propria by inflammatory cells, were noted.

Electron microscopy showed that, 2–6 weeks p.i., changes in the mid-trachea and bronchi surface consisted of the loss of cilia. Mycoplasmas covered tufts of cilia remaining on the epithelial cell surface. Scanning and transmission electron micrographs showed that they were predominantly found closely associated with the top of cilia. No specialized terminal structure could be seen and no mycoplasma cells were identified lying free in the lumen nor in close contact with the plasma membrane of cells of microvilli. Some fine fibrils radiating from one mycoplasma to another or to cilia were seen at higher magnification by scanning electron microscopy. Six to eleven weeks p.i., a disrupted epithelial surface lacking cilia was observed. Cells were desquamated and shed into the lumen with cellular remains containing droplets of mucus.

Autoradiography revealed that label corresponded to the observed mycoplasma distribution. At the top of cilia, a high density of labeling was visible in the zone of high mycoplasma concentration. Therefore, incorporation of the label in the mycoplasma is proof or their multiplication in the trachea.

The intimate association between the mycoplasma and cilia may be an important factor in the pathogenesis of the disease caused by M. hyopneumoniae (swine enzootic pneumonia).     

Ultrastructural study of infectious bronchitis virus infection in infundibulum and magnum of commercial laying hens

The infundibulum and magnum of the oviduct were examined in hens in full lay which were infected with two Australian strains of infectious bronchitis virus (IBV). The ultramicroscopic changes in the infundibulum and magnum were compared with control hens which had eggs at different positions in the oviduct. The ciliated and granular cells of the surface epithelia and secretory epithelial cells of the tubular glands were the target cells of IBV. No pathological changes were recorded during 2-8 days post-infection (p.i.). Patchy loss of cilia occurred at 10-14 days p.i. Between 16 and 24 days p.i., there was no cilia loss and lymphoid nodules were observed in the muscularis layer of the infundibulum and magnum of some hens from both infected groups. Virus particles were detected mostly in the rough endoplasmic reticulum (RER) and Golgi complex between 10 and 12 days p.i. Cytopathology was noticed in various cell organelles between the 10th and 14th days p.i. There was an increase in RER deposits in infected cells, irrespective of egg position in the oviduct. The magnum was more affected than the infundibulum. Cellular changes were more severe in the infundibulum and magnum of T-infected hens as compared to N1/88-infected hens. Eggs with watery whites which were laid by infected hens could be attributed to cytopathological changes in the granular epithelial cells and tubular gland epithelial cells of the magnum resulting in reduced synthesis of albumen proteins. IBV can cause pathology in parts of the fully functional oviduct which may persist up to the 30th day p.i. However, both the challenge strains of IBV can cause a small number of hens to cease production. Loss of cilia in both the infundibulum and magnum pose a potential threat of secondary bacterial infection and also may affect fertility in breeder hens.     

A tissue culture system to study respiratory ciliary epithelial adherence of selected swine mycoplasmas

An in vitro culture system for swine tracheal epithelial cells was developed to study the adherence of swine mycoplasmas. Swine tracheal epithelial cells were isolated by enzymatic digestion and cultured on microporous membranes. Growth medium was placed under the membrane support to create air-liquid interface feeding resulting in the cells growing cilia and microvilli on the apical surface. Two strains of Mycoplasma hyopneumoniae (pathogenic strain 91-3 and non-pathogenic type strain J) and two strains of Mycoplasma flocculare (type strain Ms42 and field isolate 7160T) were used in this study. The morphology of the cultured tracheal cells was evaluated by transmission electron microscopy. Adherence of M. hyopneumoniae and M. flocculare and damage to the cilia were demonstrated using scanning electron microscopy. The pathogenic M. hyopneumoniae strain 91-3 adhered to cilia inducing obvious damage. The non-pathogenic M. hyopneumoniae strain J did not adhere to mature cilia. Both M. flocculare strains Ms42 and 7160T adhered to mature and budding cilia. No obvious ciliary damage was observed with strain Ms42. Minimal damage consisting of a slight tangling of the cilia occurred after adherence by strain 7160T. This model will enable us to further study the role of adherence of mycoplasmas on the pathogenesis of swine pneumonia.     

Intranasal infection of ferrets (Mustela putorius furo) with canine parainfluenza virus.

Immunocompetent and cyclophosphamide-immunosuppressed ferrets were intranasally infected with canine parainfluenza virus (CPIV) and observed for clinical signs, histopathologic lesions, the immunocytochemical demonstration of CPIV antigen in the respiratory tract and scanning electron microscopic alterations of the tracheal epithelium until 36 days post infection (p.i.). In both groups, clinical signs were minimal, restricted to the upper respiratory tract and consisted of cough elicited by tracheal compression between 3 and 7 days p.i. Microscopically, inflammatory and degenerative lesions were observed in the trachea and less frequently in the nasal cavity; bronchiolitis or interstitial pneumonia was not demonstrated. By immunocytochemistry, CPIV antigen was demonstrated in tracheal epithelial cells, whereas nasal cavity, bronchi, bronchioles and lung were devoid of viral antigen. Ferrets given CPIV alone developed a minimal lymphocytic tracheitis with minimal loss of cilia and CPIV antigen was observed only 4 days p.i. 17 days p.i., normal epithelial organization and ciliary reappearance was reestablished. Ferrets treated with cyclophosphamide and infected with CPIV exhibited mild to moderate histological lesions as above with similar scanning electron microscopic changes until 36 p.i. Tracheal lesions consisted of intraepithelial and submucosal infiltration of lymphocytes and macrophages, focal epithelial hyperplasia and multifocal loss of cilia. In addition, mild and transient neutrophilic infiltration was observed. In immunosuppressed ferrets, viral antigen expression was prominent and demonstrated 4 and 8 days p.i. These data suggest that ferrets are susceptible to aerosol CPIV infection.     

Significance of surface epithelial cells in canine cerebrospinal fluid and relationship to central nervous system disease

Background: The term “surface epithelium” is used to describe cells, including meningeal, choroid plexus, ependymal, and endothelial cells, that are found in human cerebrospinal fluid (CSF) and are difficult to distinguish cytologically. We hypothesized that the presence of surface epithelial cells in canine CSF was associated with specific diseases of the central nervous system (CNS). Objectives: In this retrospective study the frequency of surface epithelial cells in CSF from dogs with neurologic disease was investigated along with the potential association with age, specific type of CNS disease, and CSF total nucleated cell count (TNCC) and protein concentration. Methods: The frequency of surface epithelial cells in 359 canine CSF samples was analyzed for 5 disease groups: CNS neoplasia, CNS compression, CNS inflammation, idiopathic epilepsy, and miscellaneous diseases. Groups were also combined into those with and without expected meningeal involvement. Association of the presence of surface epithelial cells in CSF with age, disease type, and CSF TNCC and protein concentration was investigated. Results: Surface epithelial cells were found in 27 of 359 (7.5%) CSF samples: CNS neoplasia 2/30 (6.7%), CNS compression 7/64 (10.9%), CNS inflammation 1/39 (2.6%), idiopathic epilepsy 8/124 (6.5%), and miscellaneous diseases 9/102 (8.8%). Significant associations between surface epithelial cell presence in CSF and age, disease type, CSF TNCC, and CSF protein concentration were not found. Conclusions: The presence of surface epithelial cells was not related to a specific disease group or CSF changes in the studied population. Thus, the presence of surface epithelial cells should be interpreted carefully, as it could represent an incidental finding in CSF specimens.     

Scanning electron and light microscopic studies of the surface epithelium of the rete testis and epididymis of the boar. I. Rete testis and efferent ducts

The use of the scanning electron microscope gave a three dimensional representation of the epithelial surface. Additionally, light microscopy revealed the representative structure of the epithelium. The rete testis showed a single layer of cubic epithelial cells. Short and dense microvilli were found on the surface. Sporadically a single, cilia-like structure was recognized. An extratesticular rete testis was identified. The flowing transition of the epithelium between the rete testis and the efferent ductuli occurred at different levels, so that both kinds of epithelial structures were recognized in the same area. The efferent ductuli were composed of a single columnar epithelium consisting of two cell types, principal cells and ciliated cells. The ciliated cells were recognized by their cilia protruding into the lumen. The principal cells showed microvilli on their surface and bleblike apical protrusions which erupt into the lumen.     

Scanning electron microscopic study of the lower respiratory tract in calves and adult cattle

The surface characteristics of the lower respiratory tract of two groups of cattle were studied with the scanning electron microscope. Group A comprised six one-week-old calves and group B four adult cows. None of the animals had overt respiratory disease or gross morphological evidence of pulmonary lesions. The trachea, bronchi, bronchioles and alveoli of the cranial and the caudal lobes of the right lung were examined. In both groups the luminal surface of the trachea and large bronchi were completely covered by cilia, apparently forming an efficient mucociliary escalator. In the adult animals there were some patchy areas in the trachea and large bronchi devoid of ciliated cells; these were considered abnormal. In the bronchi, non-ciliated cells, mainly mucus-secreting, were not easily identified unless they were discharging secretion. In small bronchi, non-ciliated cells were more evident and easily seen. The bronchioles had many non-ciliated cells and very few ciliated cells capable of forming a complete carpet for a mucociliary escalator. Types 1 and 2 alveolar epithelial cells and alveolar macrophages were identified in both groups. Pores of Kohn were found in the alveolar walls in all animals.