猪圆环病毒2型感染裸鼠及BALB/c小鼠的研究

用猪圆环病毒2型（PCV2）经腹腔注射BALB/c小鼠及裸鼠各15只,每隔2周1次,共感染3次.BALB/c小鼠初次、再次感染后均未出现明显的临床症状,仅有2只小鼠出现病理变化;从血清中可检测到PCV2核酸及其ORF2抗体;同时淋巴细胞增殖反应显著增强,NK和CTL细胞杀伤率显著升高;CD4^＋、CD8^＋、CD3^＋T淋巴细胞及CD19^＋B淋巴细胞数量显著减少.裸鼠也未出现明显的临床症状,从血清中可检测到PCV2核酸,但未检测到PCV2 ORF2抗体;除NK细胞杀伤率显著升高外,其余免疫学指标无显著改变.结果表明,BALB/c小鼠比裸鼠对PCV2易感,各项免疫学指标变化与PCV2感染猪一致,但不表现临床症状,仅个别BALB/c小鼠出现病理变化,说明BALB/c小鼠对PCV2不如猪易感.     

BALB/c小鼠肺组织中氧化及抗氧化系统的动态研究

为探讨BALB/c小鼠正常生理状况下肺组织中的氧化及抗氧化系统的动态变化规律,采用分光光度计法分别测定了肺组织中的黄嘌呤氧化酶（xanthine oxidase,XOD）活性、丙二醛（malondialdehyde,MDA）含量、超氧化物歧化酶（superoxide dismutase,SOD）活性变化。结果表明,在第3、6、7、12天BALB/c小鼠肺组织的XOD活性、MDA含量、SOD活性均无显著差异（P＞0.05）。说明生理状态下,BALB/c小鼠肺组织中自由基的产生与清除的酶系统之间维持动态平衡。     

Experimental infection with Toxocara cati in BALB/c mice, migratory behaviour and pathological changes

Experimental inoculations of 1000 Toxocara cati larval eggs were carried out in 18 BALB/c mice. The T. cati eggs used for inoculation were collected from the faeces of naturally infected cats. Euthanasia was performed on two mice on days 1, 2, 3, 4, 5, 6, 14, 21 and 28 post-inoculation (p.i.). Tissue samples were taken for digestion and histopathology. Larvae were recovered from all infected mice and the average of all larvae recovered was 28.3% (95%; CI: 14.1-42.4). Maximum number was obtained from liver on days 1 and 2 p.i.; from the lung on day 2 p.i. and from the brain on day 28 p.i. In muscle, the recovery was high as from day 3 p.i., with the maximum obtained on day 28 p.i. Superficial foci of congestion and haemorrhage were macroscopically observed in the lungs between days 2 and 5 p.i. and in the brain between days 3 and 6 p.i. Microscopic lesions were observed in the liver between days 2 and 14 p.i., with periportal and subcapsule inflammatory infiltrates. In the lungs, haemorrhages and inflammatory infiltrates can be observed in the alveolar parenchyma, close to bronchioles and large blood vessels. In the brain, congestive areas without inflammatory reactions were seen. In muscle, the presence of inflammatory infiltrates and degenerated muscle can be observed surrounding a parasite larva. These same lesions were observed in myocardium and pericardium. The kidneys were congested with inflammatory infiltrates. The inflammatory cells present in all the tissues studied were lymphocytes, neutrophils and a few eosinophils. Formation of granulomas or signs of larva encapsulation were not observed. The migratory pattern of T. cati larvae in BALB/c mice and its tendency to become concentrated in the muscle reinforce the importance of the mouse as a paratenic host for the parasite's cycle in the environment.     

Influence of Neospora caninum intra-specific variability in the outcome of infection in a pregnant BALB/c mouse model

Previous assays in pregnant animals have demonstrated the effect of different host factors and timing of infection on the outcome of neosporosis during pregnancy. However, the influence of Neospora caninum isolate itself has been poorly investigated. Here, we compared the effects on clinical outcome and vertical transmission observed in a pregnant mouse model following infection with 10 different N. caninum isolates. The isolates in our study included the Nc-Liv isolate and nine N. caninum isolates obtained from calves. Female BALB/c mice were inoculated with 2 × 10⁶ tachyzoites at day 7 of pregnancy. Morbidity and mortality, in both dams and offspring during the course of infection, and transmission to progeny at day 30 postpartum were evaluated. The serum IgG1 and IgG2a production in dams were also examined. All dams showed elevated IgG1 and IgG2a responses, confirming N. caninum infection, although signs of disease were only exhibited in dams infected with 4 of the 10 isolates (Nc-Spain 4H, Nc-Spain 5H, Nc-Spain 7 and Nc-Liv). In neonates, clinical signs were observed in all N. caninum-infected groups, and neonatal mortality rates varied from greater than 95% with the isolates mentioned above to less than 32.5% with the other isolates. Vertical transmission rates, as assessed by parasite PCR-detection in neonate brains, also varied from 50% to 100% according to the isolate implicated. These results confirm the wide pathogenic and transmission variability of N. caninum. The intra-specific variability observed herein could help us explain the differences in the outcome of the infection in the natural host.     

Meningioangiomatosis in young dogs: a case series and literature review

Meningioangiomatosis (MA) is a proliferative disorder of the central nervous system (CNS) that has been reported rarely in humans and sporadically in dogs. Meningioangiomatosis may occur in the brainstem or cervical spinal cord of young dogs and can be identified tentatively by magnetic resonance imaging. The histopathologic hallmark of MA is a leptomeningeal plaque that extends along the CNS microvasculature and invades the adjacent neural parenchyma. This case series describes the neurologic signs, clinical progression, diagnostic imaging, and neuropathology of 4 dogs with MA. The 4 dogs with MA are compared and contrasted with 4 previously reported cases in dogs as well as with their human counterpart.     

小鼠抗青霉素和头孢菌素酰化酶抗体制备及交叉反应研究

为探讨用不同方法制备的抗原对抗体效价的影响以及抗体之间的交叉反应 ,采用 3种不同方法制备的抗原分别免疫 BAL B/ c小鼠 ,制备出抗青霉素酰化酶 α亚基、β亚基和抗头孢菌素酰化酶α亚基、β亚基 4种抗体 ,测定了它们的效价 ;同时还比较了用同一种方法制备的抗原免疫小鼠后制作这两类抗体的效价以及上述 4种抗体之间对应抗原的交叉反应。结果表明 ,用割胶法制备的抗原免疫小鼠后所得抗体效价较高 ;同样用割胶法制备的抗原免疫小鼠后所得的两类抗体效价无显著差异 ;在交叉反应测试中 ,抗头孢菌素酰化酶抗体也能识别青霉素酰化酶 ,但抗青霉素酰化酶抗体却几乎不能识别头孢菌素酰化酶 ,即抗头孢菌素酰化酶抗体更为活跃 ,而抗青霉素酰化酶抗体则更为专一。同类抗体对应抗原 2个亚基之间的交叉反应说明其互相结合部位结构的类似 ,同时也说明只有进一步制作单克隆抗体才能筛选出特异性强的抗体     

Spontaneous Adenosquamous Carcinoma with Rapid Growth and EMT-like Changes in the Mammary Gland of a Young Adult Female BALB/c Mouse

This study histopathologically and immunohistochemically investigated a spontaneously occurring single mass subcutaneously located in the left lower abdomen of a female BALB/cAJcl−nu/+ mouse at 10 weeks of age. The mass was about 20 × 15 × 10 mm in size after formalin fixation; nevertheless, it was not detected by clinical observations at 9 weeks of age. H&E staining revealed the tumor origin was epithelial and probably arose from the mammary gland, and the tumor cells demonstrated a squamous, acinar or polyhedral/basal pattern. A cell kinetics analysis revealed that many of the tumor cells of the squamous, acinar or polyhedral/basal component were positive for PCNA and cyclin D1, although there were a few of TUNEL-positive tumor cells in all of the components. An epithelial/mesenchymal analysis demonstrated that most of the tumor cells of the squamous and acinar components contained keratin and E-cadherin; however, most of the tumor cells of the polyhedral/basal component were less or very weakly positive for these markers. The tumor cells of the squamous component were negative for vimentin and SMA; however, many of the tumor cells of the polyhedral/basal component exhibited vimentin. In addition, expression of SMA was confirmed in some tumor cells of the acinar and basal components. Based on the microscopic and immunohistochemical characterizations, the tumor was diagnosed to be adenosquamous carcinoma that originated from the mammary gland with rapid growth, and the tumor cells demonstrated epithelial-mesenchymal transition-like changes.     

Association of gastrointestinal hemorrhage with increased blood urea nitrogen and BUN/creatinine ratio in dogs: a literature review and retrospective study

Blood urea nitrogen (BUN) and serum creatine concentrations were recorded from the medical records of 52 dogs with clinical evidence for upper gastrointestinal hemorrhage (UGH) at the Colorado State University Veterinary Teaching Hospital between 1988 and 1995. Eighteen of the dogs had melena, 11 dogs had hematemesis, and 23 dogs had both melena and hematemesis. Compared with age-matched control dogs, dogs with suspected UGH had a significantly higher BUN concentration (31.0 mg/dL vs. 16.5 mg/dL), creatinine concentration (1.2 mg/dL vs. 1.1 mg/dL) and BUN/creatinine ratio (27.6 vs. 14.4). The increase in BUN/creatinine ratio suggested that the increased BUN concentration in dogs with evidence for UGH primarily was associated with increased gastrointestinal absorption of nitrogenous compounds, and hepatic ureagenesis.