A porcine model for sequential assessments of cerebral haemodynamics and metabolism

We present a physiologically stable porcine model designed for sequential assessments of pharmacological effects on mean hemispheric cerebral blood flow (CBF) and cerebral metabolic rate for oxygen (CMRO2) at sustained normocapnia. The dynamic influence of continuously administered fentanyl (0.040 mg.kg-1.h-1 i.v.), nitrous oxide (70%) and pancuronium (0.30 mg.kg-1.h-1 i.v.) on these variables was studied in eight normoventilated pigs. CBF was reliably assessable at 10-min intervals by clearance of intra-arterially injected 133Xe, monitored by an extracranial scintillation detector. CMRO2 was calculated from CBF and the simultaneously measured cerebral arteriovenous difference in blood oxygen content. The intracerebral distribution of a contrast medium injected into the external and internal carotid arteries was studied by angiography, and the cerebral venous outflow was investigated by measurements of the distribution of an intra-arterially administered non-diffusible tracer, [99mTc]pertechnetate, to the internal and external jugular veins. After a 3-h equilibration period, CBF and CMRO2 were determined on six occasions over a study period lasting 1 h 40 min. The mean ranges of these variables were 56-60 and 1.9-2.0 ml.100 g-1.min-1, respectively. We conclude that the model enables repeated assessments of CBF and CMRO2 under stable physiological background conditions and thus valid cerebral pharmacodynamic investigations of drugs given for anaesthesia.     

Age, gender and litter-related variation in T-lymphocyte cytokine production in young pigs

The capacity of farm animals to produce cytokines could be an important determinant of robustness and health. From research in rodents and humans it appears that the production and the balance of T helper 1 (Th1) and T helper 2 (Th2)-type cytokines influences susceptibility to autoimmune and infectious diseases. It is known that pigs show a large variation in many immune response parameters. So far the extent of individual variation in the production of Th1- and Th2-type cytokines in commercial outbred pigs has not been reported. In the current experiment we determined mRNA expression, as well as protein production of cytokines in 32 pigs from eight litters. From each litter two male and two female pigs were tested at 2, 5 and 8 weeks of age. Two Th1-type cytokines, interleukin (IL)-2 and interferon (IFN)-gamma, and two Th2-type cytokines, IL-4 and IL-10, were measured after phytohaemagglutinin (PHA)-stimulation of blood mononuclear cells. Cytokine production and the Th1/Th2-ratio were highly variable. The variation in cytokine protein production was moderately consistent across ages, i.e. pigs that produced high levels of cytokine at 2 weeks of age tended to do so as well at 5 and 8 weeks of age. Cytokine production tended to increase with age, and gilts and boars differed in their IL-2/IL-4 ratio. Unexpectedly, age, gender and litter effects often differed for mRNA and protein production data. We hypothesize that cytokine production is a consistent trait in pigs, especially at the protein production level. Future investigations in more animals and across a wider age range are necessary.     

Neutralizing antibodies to African swine fever virus proteins p30, p54, and p72 are not sufficient for antibody-mediated protection

Although antibody-mediated immune mechanisms have been shown to be important in immunity to ASF, it remains unclear what role virus neutralizing antibodies play in the protective response. Virus neutralizing epitopes have been identified on three viral proteins, p30, p54, and p72. To evaluate the role(s) of these proteins in protective immunity, pigs were immunized with baculovirus-expressed p30, p54, p72, and p22 from the pathogenic African swine fever virus (ASFV) isolate Pr4. ASFV specific neutralizing antibodies were detected in test group animals. Following immunization, animals were challenged with 10(4) TCID(50) of Pr4 virus. In comparison to the control group, test group animals exhibited a 2-day delay to onset of clinical disease and reduced viremia levels at 2 days postinfection (DPI); however, by 4 DPI, there was no significant difference between the two groups and all animals in both groups died between 7 and 10 DPI. These results indicate that neutralizing antibodies to these ASFV proteins are not sufficient for antibody-mediated protection.     

Immunoaffinity chromatography for purification of Salbutamol and Clenbuterol followed screening and confirmation by ELISA and GC-MS

Screening and confirmatory methods for the determination of Salbutamol (SAL) and Clenbuterol (CL) in swine urine were established. The polyclonal antibody against SAL was prepared, which was used to develop the indirect competitive enzyme-linked immunosorbent assay (ELISA) with the limit of detection of 0.5 ng/ml, and to prepare the immunoaffinity chromatography column. The immunoaffinity column could extract and purify SAL and CL simultaneously, with a binding capacity of 400 ng for SAL and 416 ng for CL. After purification, the swine urine samples were screened by ELISA for the presence of SAL and/or CL, and the positive samples were further confirmed and quantified by gas chromatography-mass spectrometry (GC-MS). The results showed that 95% of the positive samples were confirmed by GC-MS with various levels of SAL (1.1-4.6 ng/ml) and/or CL (1.9-229.1 ng/ml) residues in the incurred samples, and all the negative samples were confirmed with no SAL and/or CL residues.     

猪粪饲养家蝇幼虫的营养成分研究

目的 :分析猪粪饲养家蝇 (Muscadomestica)幼虫的营养成分。方法 :引种野生家蝇 ,用猪粪饲养幼虫 ,收获 3期老熟幼虫 ,测定粗蛋白、粗脂肪、氨基酸和脂肪酸构成及微量元素含量 ,用粮食与农业组织 世界卫生组织 (FAO WHO)提出的参考蛋白模式评价 ,并与麦麸饲养的幼虫及鱼粉比较。结果 :每公斤猪粪平均可产(0 13± 0 0 4)～ (0 2 0± 0 12 )kg鲜蛆 ,鲜蛆烘干比为 1∶0 31± 0 12 ,粗蛋白 42 36 %～ 5 2 33 % ,必须氨基酸含量占总氨基酸的 45 10 % (E % ) ,必须氨基酸与非必需氨基酸总量的比值 (E/N)为 0 82 ,E % /T为 3 0 1,脂肪酸含量为 13 73 %～ 16 83 % ,油酸、亚油酸及亚麻酸等必需脂肪酸分别为 36 99% ,7 6 1%和 0 35 % ,Fe 2 91 5mg/kg ,Cu 87 5 5mg/kg ,Zn 2 46 8mg/kg ,Mn 2 49 45mg/kg ,比麦麸饲养幼虫更接近参考蛋白模式 ,营养价值优于鱼粉。结论 :猪粪饲养的家蝇幼虫比麦麸饲养的幼虫更接近参考蛋白模式 ,营养价值优于鱼粉     

猪背驮式原位肝移植的动物模型

为建立猪背驮式原位肝移植（ＰＢＯＬＴ）模型,共施行ＰＢＯＬＴ１２次。结果表明：１２次ＰＢＯＬＴ术后成活１０头,手术成功率８３３％;平均手术时间７±１ｈ,平均无肝期３４±１２ｍｉｎ,平均失血量１２００±２００ｍｌ。术后各时期病理学检查示移植肝形态结构正常。提示建立猪ＰＢＯＬＴ模型具可行性。缩短无肝期对手术成功有重要意义。     

Acute effects on systemic circulation after intratracheal instillation of Curosurf or Survanta in surfactant-depleted newborn piglets

Systemic vasodilatation in surfactant-depleted newborn piglets is induced by 200 mg/kg of modified porcine lung surfactant (Curosurf™). The aim of this investigation was to study whether this effect is dependent on dose and could further be induced by instillation of a bovine surfactant preparation (Survanta™). Twenty-two 3–5-d old piglets were subjected to repeated saline lung lavage and then randomized to one of three groups. Instillation of either Curosurf 100 mg/kg ( n = 8), Survanta 100 mg/kg ( n = 7) or Curosurf 200 mg/kg ( n = 7) was performed through the endotracheal tube. Systemic vascular resistance decreased 7 (± 4)%, 15 (± 12)% and 18 (± 6)% in the three groups, respectively ( p < 0:05 in all three groups). A significant difference between the high and low dose Curosurf groups was found ( p < 0:05), whereas no significant difference was seen between the Curosurf 100 mg group and the Survanta group. The decrease in vascular resistance was compensated by an increase in cardiac output, resulting in a stable mean arterial blood pressure. In conclusion, both Curosurf and Survanta induce a significant decrease in systemic vascular resistance in surfactant-depleted newborn piglets. A more pronounced effect was observed after 200 mg/kg than after 100 mg/kg of Curosurf.     

大鼠胰腺炎相关性急性肺损伤模型的探讨

目的研究重组纳豆激酶(recombinant nattokinase,r-NK)大剂量重复给药对Beagle犬和小型猪凝血和纤溶系统的不同影响。方法用血球计数仪测定血小板相关参数;用血凝仪采取凝固法依次测定纤维蛋白原(Fib)含量、活化部分凝血酶时间(APTT)、凝血酶原时间(PT)、凝血酶时间 (TT);以ELISA法分别测定纤溶酶原(PLG)、纤溶酶原激活因子(t-PA)活性。结果药物对Beagle 犬和小型猪有相似的血管刺激作用。给药1周后Beagle犬血小板计数下降,PT明显延长,Fib含量明显降低,PLG活性升高。而药物对小型猪的各项参数均无明显影响。结论不同动物对相同剂量r-NK毒性反应存在较大的差异性,r-NK大剂量重复给药可破坏Beagle犬的凝血/纤溶系统平衡,而不影响小型猪凝血/纤溶系统功能。