小型猪渐进性梗阻性黄疸模型的建立

目的建立小型猪慢性渐进性梗阻性黄疸模型，评价其模拟临床渐进性梗阻性黄疸患者的价值。方法开腹手术，将并行有16G注射器针头的胆总管用5％碘酒溶液浸泡处理的10号丝线捆扎后，抽除针头。使胆总管早期部分狭窄，后期组织受化学物质刺激发生无菌性炎症反应、纤维组织修复等病理改变，引发胆管组织慢性纤维瘢痕狭窄，造成渐进性梗阻性黄疸。结果实验动物术后观察28d无死亡，第5—7天逐渐出现黄疸，之后渐重；第28天时的总胆红素较术前明显升高[（1．22±0．41）μmol／L比（125．90±35．77）μmol／L（P〈0．01）]；4周后病理显示胆总管组织发生慢性纤维瘢痕样变，管腔狭窄阻塞。结论本小型猪动物模型模梗阻性黄疸呈渐进性、慢性过程。可重复性强、耐受性好，是比较理想的梗阻性黄疸动物模型。同时，小型猪肝胆系统的生理及解剖结构与人相近，可为临床胆管狭窄和肝门部癌相关研究提供较可靠实验依据。     

猪血免疫球蛋白的分离及功能性研究

使用食品级的多聚磷酸钠（以下简称Ｓｐ）絮凝剂分离猪血浆中的免疫球蛋白，配合随机质心映射优化程序（ＲＣＯ）确定分离最佳条件，并用ＥＬＩＳＡ初步测定了粗制ＩｇＧ的各种功能特性。     

中国版纳猪MHCI类P1分子全长的原核表达与纯化

目的：获得原核表达的中国版纳猪ＳＬＡＩ类Ｐ１蛋白质分子。方法：ＰＣＲ扩增去信号肽的ＳＬＡＩ类Ｐ１ｃＤＮＡ序列，亚克隆至ｐＧＥＭＴ载体，测序。将亚克隆的Ｐ１　ｃＤＮＡ片段插入表达载体ｐＥＴ４２ｂ（＋），构建重组表达质粒ｐＥＴ－４２ｂ（＋）／ｓｌａ－ｐｌ，转化Ｅ·ｃｏｌｉ表达菌 ＢＬ２１－ＣｏｄｏｎＰｌｕｓ（ＤＥ３）－ＲＩＬ，ＩＰＴＧ诱导 Ｐ１－８ ｘ ｈｉｓ融合蛋白表达，经包涵体洗涤，８ ｍｏｌ／Ｌ尿素变性溶解，Ｎｉ２＋亲和层析，梯度透析后，定量保存。ＳＤＳ－ＰＡＧＥ、ｗｅｓｔｅｒｎ－ｂｌｏｔｔｉｎｇ鉴定目的蛋白的表达与纯化。结果：目的蛋白（分子量３９．５ ｋＤ）表达量占细菌总蛋白 １５％，每升表达菌获得纯度９５％的目的蛋白 ４０ ｍｇ～６０ｍｇ。结论：成功建立猪 ＳＬＡ分子全长原核表达、纯化体系，为建立间接识别猪移植抗原ＳＬＡＩ类分子的人Ｔ细胞系及表位分析打下基础。     

Ontogenetic development of proenkephalin A and proenkephalin B messenger RNA in fetal pigs

Summary Using solution hybridization analysis and Northern blotting with complementary RNA probes labelled to high specific activity, levels of proenkephalin A and B mRNA were analyzed throughout prenatal development in the hippocampus and striatum of fetal pigs. A differential time course for the appearance of these opioid precursor mRNAs was observed: in hippocampus, both mRNAs increased linearly throughout development with proenkephalin B mRNA increasing faster than proenkephalin A mRNA. In striatum, both mRNAs behaved similarly, increasing to a maximum level around mid-gestation and declining thereafter. The differences might be attributed to differential localization of the two precursor systems in the tissues and might be of functional relevance.Abberviations PENK A, PENK B Proenkephalin A, B - mRNA Messenger Ribonucleic Acid - cRNA Complementary RNA     

Lamellar cells of sensory receptors and perineural cells of nerve endings of pig skin contain cytokeratins

Summary The lamellar cells of the sensory corpuscles of the pig dermis must be considered to be epithelial cells as they contain cytokeratins. The cytokeratins detected are similar to those found in simple epithelia. Moreover, lamellar cells are embedded in an extracellular matrix reminiscent of the basement membrane of epithelium since it contains laminin and collagen IV. The perineural cells surrounding the nerves of pig dermis present the same features.These results suggest that lamellar cells and perineural cells have the same origin. The nature of the lamellar and perineural cells of the rabbit or human dermis is not as clear since cytokeratins were not detected in those cells. These results, together with recent observations on Merkel cells, may indicate that epithelio-neuronal junctions are a general feature of cutaneous sensory receptors.     

Effects of frustration on behaviour and plasma corticosteroid levels in pigs

Frustration was elicited in pigs by not rewarding the operant response of subjects having learnt to press a panel with their snout to get a food reward. When pigs were exposed singly to this situation, they extinguished their operant responding. Plasma corticosteroid levels increased during frustration and the number of responses emitted was correlated negatively with the initial plasma corticosteroid levels. When two pigs were submitted together to the frustration situation, they developed aggressive behaviour accompanied by increases of plasma corticosteroid levels. These experiments demonstrate that pigs are sensitive to the effects of frustration elicited by the omission of an expected reward.     

Postnatal growth of lung parenchyma in the piglet: Morphometry correlated with mechanics

Background: A previous study of piglet lung growth (Mansell et. al. 1989. J. Appl. Physiol., 67:1422–1427) showed transient stiffness to changes in shape and volume immediately after birth. Later, elastic recoil was found to increase as the lung grew in weight and volume. The present study uses morphometry to test possible structural correlates of these two mechanical changes. Methods: Piglet lungs were fixed near full inflation via the airways during the immediate newborn period (6–12 hours, n=3), at 3–5 days (n=6), 25–30 days (n=5), and 80–85 days (n=3). Morphometry comprised arithmetic and harmonic mean thicknesses of alveolar septae and average mean surface curvature. Measurements of curvature and airspace volume were combined to differentiate alveolar expansion from septal proliferation as mechanisms for volumetric growth. Results: The unique mechanical behavior of the newborn lungs was associated with relatively thick alveolar septae. Marked thinning of the septae and resolution of the stiffness to shape and volume change had occurred by 3–5 days. An increase in elastic recoil during the first postnatal month was found to be associated with simple airspace expansion. The second and third months were characterized by septal proliferation and increase in arithmetic mean septal thickness but elastic recoil did not increase further. Harmonic mean septal thickness and airspace volume per gram of lung tissue did not change over the course of the study. Conclusions: 1) A relative stiffness to shape and volume change in freshly newborn piglet lung is associated with relatively thick alveolar septal walls; 2) postnatal development of piglet lung parenchyma involves septal lengthening and thinning followed by septal proliferation; 3) the initial phase of septal lengthening, rather than the later phase of septal proliferation, is associated with increase in parenchymal recoil. © 1995 Wiley-Liss, Inc.     

Microvasculature of regular and irregular areolae of the areola-gland subunit of the porcine placenta: structural and functional aspects

To examine the vasculature of the areola-gland subunit of advanced pig placenta, tissues from ten animals between 43 and 112 days of gestation were prepared for histology and for scanning electron microscopy of vascular corrosion casts from both maternal and fetal sides. Regular areolae, tributary to one gland only, are round with a wide-meshed and smooth subepithelial capillary network on the maternal side, which is similar to the pre-implantative stage and bordered by an abrupt rim towards the interareolar maternal capillary network. On the fetal side, the capillary network follows papillae which protrude into the areolar cavity or converge to form a ring towards the areolar periphery. Irregular areolae, in contrast, have indistinct boundaries and are characterized by two or more gland openings. The maternal capillary network has moderate density and follows the corrugations, whereas the fetal capillary network is basically two-dimensional with some blunt sinusoidal protrusions. Vessel architecture of both areolar types implies facilitated external inflow of blood into the areola on arteriolar as well as on capillary levels, whereas the outflow from the areolar capillaries comprises venules converging into one or two areolar stem veins, and therefore conducts venous blood in a manner different from that of the interareolar region. It is suggested that this arrangement could favour vascular control mechanisms in uterus, placenta and fetus. On the basis of these observations and the discussion, it is suggested that these areolaspecific vessel systems are important for sustaining the characteristic substance transfers in the areola, the secretion, metabolism and absorption, which according to the literature are not the same in the regular as in the irregular areolar type of the porcine areola-gland subunit of the placenta.     

Cardiac postjunctional supersensitivity to β-agonists after chronic chemical sympathectomy with 6-hydroxydopamine

Summary The sensitivity to sympathomimetic amines of isolated atria removed from sham-injected and 6-hydroxydopamine-treated (6-OHDA) guinea-pigs was examined in the presence of an extraneuronal uptake blocker and an -adrenoceptor antagonist. Three weeks of pretreatment with 6-OHDA resulted in leftwards shifts of the dose-response curves for the positive chronotropic and inotropic responses of right and left atria to isoprenaline. The responses to the partial agonist salbutamol were also potentiated after 6-OHDA pretreatment, revealed as an increase in the maximum response relative to isoprenaline.The supersensitivity was post-synaptic in origin and independent of changes in disposition or metabolism, since it was observed with agonists immune to neuronal uptake and O-methylation, and in the presence of extraneuronal uptake inhibition by metanephrine. It was also specific for the -adrenoceptor, no supersensitivity to histamine being found. In the right atria, the supersensitivity was partially masked by an opposing depressant effect after 6-OHDA pretreatment which was observed with histamine.Dissociation constants (K _A) for the left atrial inotropic responses to orciprenaline were determined by use of the antagonist Ro 03-7894. Atria from 6-OHDA-pretreated animals were supersensitive to orciprenaline, but the K _A value did not differ from that after sham injection. It could therefore be concluded that the increase in sensitivity was not due to an increase in affinity for the -adrenoceptor.