犬感染性心内膜炎研究进展

感染性心内膜炎(Infective Endocarditis,IE)是犬的一种致命性疾病,由病原微生物侵入心脏瓣膜或心内膜内皮细胞所引发。细菌是从病变瓣膜和壁内膜组织中分离的主要病原体,因此也称细菌性心内膜炎。临床上,犬患IE并不常见,但一旦发生,死亡率极高。IE由于病情发展迅速,缺乏特异性的临床症状,因此早期诊断比较困难。文章主要从发病机制、临床症状、诊断、治疗等方面对犬IE进行了综述,为有效防治该病提供依据。     

槟榔在口腔黏膜下纤维性变发病机制中的作用

口腔黏膜下纤维性变（Oral Submucous Fibrosis，OSF）是一种以炎症和渐进性黏膜改变导致进行性张口困难为特征的口腔黏膜慢性病症．近年来相当多的流行病学研究资料指出槟榔是OSF的主要病源因子，在OSF的发病上，不论是嚼食槟榔的频率还是持续的时间都呈现了剂量依赖性．在嚼食槟榔时粗糙纤维对口腔黏膜产生的强烈机械刺激作用、槟榔中的生物碱与单宁对细胞外基质分子的影响以及槟榔中的铜在纤维化疾病中的作用等方面对槟榔在OSF发病原因与发病机制中的作用加以综述，旨在分析迄今为止国内外学者对槟榔在OSF上所做的研究，以期让基础科研人员、公共卫生工作者以及广大槟榔嗜好者对槟榔在人类OSF中的作用有更深入的了解．     

Pathogenesis and epidemiology of spontaneous exophthalmos in the West Australian dhufish, Glaucosoma hebraicum Richardson

The West Australian dhufish, Glaucosoma hebraicum Richardson (family Glaucosomatidae) is a potentially valuable aquaculture species, but spontaneous exophthalmos is common in freshly caught and cultured dhufish. To investigate the epidemiology and pathogenesis of exophthalmos in tanks of wild-caught and captive-bred dhufish, records of culture conditions, the prevalence of lesions and pathological examinations were used to study the disease and associated environmental and management factors. Naturally occurring cases of exophthalmos that were examined were mostly unilateral and occurred more frequently in summer months during periods of increasing water temperature. In 15 affected eyes that were examined histologically gas bubbles and haemorrhages were consistently present in the choroid. In some, gas bubbles and haemorrhage were also present in retrobulbar tissues associated with perforation of the sclera. Oxygen concentrations were measured in 12 exophthalmic eyes and concentrations of 50–73% were recorded in gas bubbles in the anterior chamber of three of these that were acute cases. Very low oxygen tensions were recorded at the retinal–vitreal junction of four eyes with retrobulbar haemorrhages indicating that there may have been disruption of arterial blood supply to the choroid in chronic lesions or with perforation of the sclera. The results of experiments to determine the significance of exercise, high water temperature, sudden increases in light intensity, fish handling or tank cleaning indicate that exercise and/or high water temperature (25.5 °C) may be important risk factors for the development of exophthalmos in dhufish. Possible mechanisms for the formation of gas bubbles and haemorrhage in the choroid are discussed.     

Histopathological studies on viral nervous necrosis of sevenband grouper, Epinephelus septemfasciatus Thunberg, at the grow-out stage

Abstract Viral nervous necrosis caused by sevenband grouper nervous necrosis virus (SGNNV) has occurred in grow-out stages (0-3 years old) of sevenband grouper, Epinephelus septemfasciatus, since the 1980s. In the present study, based on histopathological features of the central nervous system (CNS) in naturally diseased fish, pernasal infection experiments using grow-out fish were performed and pernasal infection was established as a putative invasion route of SGNNV. The definite SGNNV-targeted cells were determined by histopathological studies including indirect fluorescent antibody test and electron microscopy. Nerve cells in the olfactory lobe were most extensively necrotized with vacuolation followed by infiltration of microglia and macrophages. Purkinje cells and Golgi cells were extensively infected in the cerebellum. Megalocells and small nerve cell nuclei were also infected in the preoptic area, thalamus, medulla oblongata and spinal cord. Only a few small nerve cells were infected in the olfactory bulb and optic tectum. The retina of some diseased fish displayed vacuolated bipolar cells of the inner nuclear layer and in the ganglion cell layer. These SGNNV-infected nerve cells displayed viroplasmic inclusions containing virions, vacuoles and myelin-like structures. Based on observed histopathological changes, the lesion of the CNS was characterized by encephalitis but not encephalopathy.     

茶毛虫核型多角体病毒安全性试验

茶毛虫核型多角体病毒对茶毛虫的防治效果达70—80％。安全性试验结果表明:大鼠经口一次、多次和长期喂饲,经呼吸道吸入;豚鼠和家兔经皮、眼粘膜接种,均未引起异常表现,各项生理、生化指标正常,未见病理致变及EPNPV侵染。大鼠生殖试验F_0及F_1代鼠受孕率、活产率、哺育成活率等指标均正常,未引起畸胎;F_1代鼠生长良好。EPNPV对小鼠未见显性致死效应。上述结果表明,EPNPV对实验动物是安全的。     

African horsesickness: Pathogenesis and immunity

African horsesickness (AHS) is a serious, non-contagious disease of horses and other solipeds caused by an arthropod-borne orbivirus of the family Revoiridae. In horses, AHS causes three distinct clinicopathologic syndromes, the pulmonary, cardiac and fever forms of the disease. Recent work has shown that the primary determinant of the form of disease expressed by naive horses is the virulence of the virus inoculum. Horses which recover from AHS exhibit solid humoral immunity against homologous challenge. Protective antibodies appear to be directed towards neutralizing epitopes on AHS virus VP2. The relationship of neutralization to protection and vaccination is discussed.     

Experimental Elaphostrongylus cervi infection in moose (Alces alces)

An 8-week-old male moose calf was inoculated with 360 infective third-stage larvae (L3) of E. cervi. The calf started to expel first-stage larvae (L1) of E. cervi in faeces 63 days after inoculation. The highest faecal larval count of 1,920 L1 per gram faeces was recorded 133 days post inoculation. Clinically, intermittent lameness, mild ataxia and general stiffness were observed over a 3 months’ period from day 75 after inoculation. The symptoms were moderate, faded gradually and were not seen during the last three weeks of the observation period. The calf had a good appetite and the bodyweight increased continuously throughout the experiment. On day 202 after inoculation the calf was euthanized and autopsied. Adult E. cervi were found in the epidural space of the central nervous system (CNS) and in skeletal muscles. Oedema, haemorrhages, discolouration and extensive inflammatory reactions were observed in the fat and loose connective tissue of the epidural space between the 5 th cervical vertebra and cauda equina. Nematodes or lesions indicating nematode infestation could not be demonstrated in the leptomeninges or in the neural parenchyma of the CNS. Numerous eggs and larvae of E. cervi associated with moderate pathological changes were observed in the lungs.     

Contribution of AIDA-I to the pathogenicity of a porcine diarrheagenic Escherichia coli and to intestinal colonization through biofilm formation in pigs

In order to evaluate the role of the AIDA-I of porcine diarrheagenic Escherichia coli strain PD20 serogroup O143 (AIDA-I⁺, STb⁺), a mutant strain PD20M (AIDA-I⁻, STb⁺) was generated from strain PD20 by an allelic exchange procedure. In addition, the full-length aidA gene was reintroduced into strain PD20M to generate the complemented strain PD20C (pTaidA, AIDA-I⁺, STb⁺). A non-pathogenic E. coli strain PD71 was used as negative control. Each strain was inoculated to newborn pigs via stomach tube. Severity of diarrhea was evaluated clinically and intestinal colonization was assessed by histology, immunohistochemistry (IHC), and transmission electron microscopy (TEM) including immunogold electron microscopy (IGEM). The adhesion pattern to HeLa cells, bacterial auto-aggregation and biofilm formation were evaluated in vitro. Pigs infected with strains PD20 or PD20C developed diarrhea 16 and 28 h after inoculation, respectively, in contrast to pigs infected with strains PD20M or PD71. Histology, IHC, TEM and IGEM examinations showed heavy bacterial colonization with biofilm formation in the large intestine, and marked in vivo expression of AIDA-I protein in pigs infected with strains PD20 or PD20C in contrast to pigs infected with strains PD20M or PD71. The in vitro assays showed marked diffuse adherence to HeLa cells, enhanced bacterial auto-aggregation and significant biofilm formation (p < 0.05) by the AIDA-I⁺ strains, when compared to AIDA-I⁻ strains. These results demonstrate that expression of AIDA-I is essential for intestinal colonization and in vitro bacterial autoaggregation and biofilm formation. Thus, AIDA-I may be considered a significant virulence determinant in development of diarrhea caused by porcine diarrheagenic AIDA-I⁺ E. coli PD20 in piglets.     

结直肠癌基因组流行病学研究进展

基因组流行病学的研究是近年来遗传流行病学与分子流行病学相互融汇交织而发展起来的新兴学科,它是从基因组学研究到医学实践的重要桥梁。全世界范围内,结直肠癌的发病率及死亡率有逐年上升的趋势,因此有必要从基因组流行病学的角度认清结直肠癌的流行病学及分子发病机制。本文重点围绕基因-基因以及基因-环境的交互作用对结直肠癌的影响作一阐述,旨在为结直肠癌基因的靶向治疗提供理论依据。     

猪圆环病毒的致病机理

猪圆环病毒（PCV2）是近年来发现的一种新病毒。该病毒主要侵害哺乳仔猪和育肥猪。主要引起猪断奶后多系统衰竭综合症（PMWS）、猪皮炎肾炎综合症（PDNS）、增生性坏死性肺炎（PNP）、猪呼吸道病综合症（PRDC）、繁殖障碍、先天性颤抖、肠炎等疾病。严重影响猪生长发育。且致死率较高，此病可引起典型的临床症状和病理变化。其典型的临床症状为患猪体质不良、皮肤苍白或有黄疸、消瘦、死亡等，病理特征主要为全身器官的炎性变化。该病自1991年开始报道以来．已成为严重影响养猪业发展的传染病之一，引起了世界许多国家兽医工作者的高度重视。