含谷氨酰胺双肽肠外营养在门腔分流术后应用的临床研究

目的　探讨门腔分流术后病人给予含丙氨酰 谷氨酰胺双肽 (Ala GLN)肠外营养 (PN)的安全性 ;观察其营养支持的效果 ,及对肠道通透性的影响。方法　 16例病人随机分为两组。对照组(n =7)接受不含GLN的PN ;实验组 (n =9)接受含Ala GLN双肽的PN。两组自术后第 1天起给予等氮、等热量的PN共 7d ,于PN前后分别测定血清前白蛋白、氮平衡变化、血清GLN浓度、血氨、尿乳果糖 /甘露醇排泄率比值 (L/Mratio)、生化和临床指标的变化。结果　对照组术后血清GLN水平比术前显著降低 ,术后实验组GLN水平 (5 77± 4 2 ) μmol/L显著 (P =0 0 0 9)高于对照组术后水平 (499± 6 1)μmol/L ;两组术前的L/M比率均明显高于国人正常水平 ,术后对照组L/M水平 (0 0 95± 0 0 34)显著 (P=0 0 4 5 )高于实验组 (0 0 6 4± 0 0 2 3) ;两组累积氮平衡无显著性差异 ,但实验组第 5～ 7天期间氮平衡要明显优于对照组 ,实验组第 5天氮平衡 (- 15 3± 4 6 9)mg·kg-1·d-1显著 (P =0 0 4 3)好于对照组 (-92 7± 90 5 )mg·kg-1·d-1;对照组术后血清前白蛋白水平较术前显著下降 ,实验组术后血清前白蛋白水平 (0 2 6 9± 0 0 37)g/L显著 (P =0 0 0 1)高于对照组 (0 199± 0 0 2 7)g/L ;两组术后血氨水平相比无统计学意义 ;生     

Ependymal lining of infundibular recess in perinatal rats: Relationships with portal capillaries and permeability

Structure and permeability of the ependymal lining the infundibular recess were studied in perinatal rats with silver impregnation, electron microscopy, radioautography, and tracer techniques. According to our data basal processes of ependymal cells reach the primary portal plexus linking the 3rd ventricle and the hypophysial portal system all through the perinatal period. After birth, some of the processes penetrate into the perivascular space of the primary portal plexus and abut there on the endothelium of capillaries. Ependymal cells of fetuses and neonates are joined by specialized junctions (tight junctions, gap junctions and zonulae adhaerentes). Intraventricularly injected ionic lanthanum crosses the ependymal lining of fetuses both trans- and extra-cellularly everywhere in the infundibular recess. By postnatal day 9 only the rostral portion of the recess remains readily permeable. Caudally, extracellular leakage becomes highly restricted, apparently due to the appearance of circumferential tight junctions. Finally, [3H]dopamine seems to penetrate through the ependymal lining in the same way as ionic lanthanum entering the portal capillaries. These findings suggest that the adenohypophysiotropic neurohormones can penetrate from the cerebrospinal fluid into the portal circulation from the very beginning of the establishment of the hypothalamo-hypophysial functional relationships during ontogenesis.     

表皮生长因子改善移植小肠黏膜屏障功能的实验研究

目的了解表皮生长因子(epidermalgrowthfactor,EGF)对移植小肠通透性及细菌易位的作用。方法以Wistar大鼠为供体,SD大鼠为受体行异位全小肠移植,并以环孢素A(CsA,6mg.kg-1.d-1,im)抑制排斥反应。表皮生长因子组(EGF组)用微量输液泵持续均匀输入EGF200μg.kg-1.d-1;对照组输入等量生理盐水。第7天以乳果糖及甘露醇行移植肠灌注并收集尿液行高效液相色谱仪分析乳果糖及甘露醇含量,第8天采集移植肠系膜淋巴结及门静脉血行细菌培养。结果对照组尿液中乳果糖含量[(0.093±0.008)vs(0.015±0.002),P=0.0001]及乳果糖/甘露醇比值[(0.132±0.021)vs(0.020±0.005),P=0.0001]明显高于基准,EGF组乳果糖含量[(0.043±0.008)vs(0.015±0.002),P=0.0054]及乳果糖/甘露醇比值[(0.060±0.017)vs(0.020±0.005),P=0.0029]也较基准增加,EGF组乳果糖含量[(0.043±0.008)vs(0.093±0.008),P=0.0067)及乳果糖/甘露醇比值[(0.060±0.017)vs(0.132±0.021),P=0.0116]显著低于对照组。EGF组移植肠系膜淋巴结细菌阳性率为10%,对照组阳性率为60%,明显高于EGF组(P=0.028)。EGF组与对照组门静脉血培养阳性率比较差异无统计学意义(P>0.05)。结论本研究提示EGF能够降低同种移植小肠的通透性及细菌易位率,改善肠黏膜屏障功能。     

戊二醛交联甲壳胺膜的制备及其渗透性的研究

本文制备戊二醛交联甲壳胺膜。研究了戊二醛交联对膜的亲水性，结晶性的影响；探讨了交联对肌肝、尿素、尿酸的渗透；测定膜在于干态和湿态下的力学机械性能。     

CO对局灶性缺血脑组织血脑屏障通透性的影响

目的:研究一氧化碳及其限速酶(血红素氧合酶-1)对局灶性缺血脑组织血脑屏障通透性的影响。方法:将SD大鼠随机分为3组(n=6),使用血红素氧合酶诱导剂及抑制剂腹腔注射,用等量生理盐水腹腔注射作为对照组,12h后复制MCAO模型。梗塞后24h后检测血液中一氧化碳浓度、血脑屏障通透性。结果:诱导剂组一氧化碳浓度明显高于对照组(P＜0.01),血脑屏障通透性明显低于对照组(P＜0.05),而抑制剂组一氧化碳浓度明显低于对照组(P＜0.01),血脑屏障通透性明显高于对照组(P＜0.05)。血红素氧合酶诱导剂、抑制剂对非梗塞侧的血脑屏障通透性没有影响(P＞0.05)。结论:一氧化碳作为一种信使分子,脑缺血时浓度升高具有保护血脑屏障的作用。     

Mechanical and Cellular Changes During Compaction of a Collagen-Sponge-Based Corneal Stromal Equivalent

The need for corneas suitable for transplantation, combined with the decreasing supply, has fueled interest in the development of a corneal replacement. In this study, a collagen-sponge-based stromal equivalent, consisting of human corneal fibroblasts cultured on a type I collagen sponge, was maintained in culture for up to 21 days and characterized with respect to mechanical properties and cellular behavior. The Young's modulus of the stromal equivalent varied from 95 to 370 Pa, and its permeability varied from 5.3 x 10(-8) - 4.2 x 10(-7) m4 N(-1) s(-1). The greatest changes occurred during the first few days in culture, but the mechanical properties continued to change during the entire 21 days. Cell traction stress, determined from sponge compaction and DNA count, decreased during the compaction process with the maximum traction value the initial value of 6.6 +/- 2.9 x 10(-3) Pacm3 cell(-1). Microarray data showed that the expression level of fibronectin, decorin sulfate, collagenase, and gelatinase A was upregulated at day 14 in the sponge. This suggested that the repair fibroblast phenotype was being expressed by the fibroblasts. Additional analysis suggested that a subpopulation of cells expressed the myofibroblast phenotype.     

The diffusion of carbon dioxide in erythrocytes and hemoglobin solutions

Summary The CO₂ diffusion constant (Krogh's diffusion constant) has been estimated from the CO₂ flux across layers with defined thickness under steady state conditions.At 22°C and in hemoglobin solutions with a concentration of 33 g% the diffusion constant for CO₂ was found to be 3.3×10^–4 cm² min^–1 atm^–1. This value is about 40% of the diffusion constant for CO₂ in water. The relationship between the diffusion constant and the hemoglobin concentration was approximately linear in a concentration range of 10–40 g%. The temperature coefficient of the diffusion constant was –0.5%/°C both in water and hemoglobin solutions. At 38°C and in a hemoglobin solution with a concentration of 33 g%, the diffusion constant for CO₂ was therefore 3.0×10^–4 cm² min^–1 atm^–1, the diffusion coefficient 11×10^–6 cm² s^–1.A general theory for the diffusion of CO₂ in hemoglobin solutions has been derived. According to this theory the diminution of the CO₂ diffusion in hemoglobin solutions in comparison to water can be explained quantitatively by a reduction of the water space by the hemoglobin molecules.The diffusion constant for CO₂ in layers of erythrocytes was insignificantly (0–3%) smaller than in hemoglobin solutions with the same hemoglobin concentration. It is concluded that the erythrocyte membrane does not offer a considerable resistance for the CO₂ diffusion.     

Permeability changes of Ehrlich mouse ascites tumor cells induced by a cytotoxin from Pseudomonas aeruginosa

Summary Ehrlich ascites tumor cells from mice were damaged during in vitro incubation with a cytotoxin from Pseudomonas aeruginosa at concentrations of>1 g/ml. After a short time the cells started to lose potassium whereas their sodium content increased. When the protein concentration of the incubation medium was adjusted to the protein concentration inside the cells, swelling and release of glucose-6-phosphate dehydrogenase was avoided. However, lysis of the cells still took place.Preincubation of cells with tetrodotoxin, 4-aminopyridine or tetraethylammonium did not influence damage to the cells. The cells showed a steep increase in toxin response between 17° and 27°C ranging from insensitivity to full sensitivity.An increase in electrical conductance was measured during incubation of cholesterol bilayer membranes with a cytotoxin concentration of 1 g/ml. The conductance was increased by a factor of ten within 30 min at 25°C which indicates the involvement of membrane lipids in the cytotoxin action.Part of this study has been presented at the Joint Meeting of the Scandinavian and German Pharmacological Societies, Lübeck (Grieshaber and Lutz 1980)     

Barrier function of porcine choroid plexus epithelial cells is modulated by cAMP-dependent pathways in vitro

In the present paper, we demonstrate that the barrier properties of primary cultured epithelial cells isolated from porcine choroid plexus are regulated by cAMP-dependent signal transduction pathways in vitro. Triggering cAMP-connected cascades in cell layers grown on permeable filters with cAMP-analogues or forskolin led to a significant increase of transepithelial electrical resistances and a pronounced reduction in the permeation rate of a 4 kDa-dextran probe. In dose-response experiments using the cAMP-analogue 8-(4-chlorophenylthio)-cAMP transepithelial electrical resistances were observed to increase above a threshold concentration ranging between 10(-5.5) and 10(-5) M. Additional impedance studies performed with confluent cell layers grown on gold-film electrodes revealed that the observed changes in transepithelial resistances and presumably also in macromolecular permeation rates were not entirely caused by a reinforcement of intercellular junctions but also contained contributions from changes in the cell-substrate adhesion pattern. These inherent contributions to the electrical resistance and macromolecular permeability are caused by a restricted diffusion pathway between basal plasma membrane and culture substrate that have to be considered in data analysis, especially when leaky cell layers on filter substrates with low pore densities are used.     

透皮促透剂对复方酮康唑乳膏体外透皮吸收的影响

目的：观察不同促透剂对复方酮康唑乳膏中酮康唑在体外透皮作用的影响。方法：采用改良的简单小室装置，以离体鼠皮为透皮屏障，用高效液相色谱法(HPLC)测定含量，计算累积透皮吸收百分率。结果：5种促透使用方法对乳膏中酮康唑均有促透作用。结论：5种促透使用方法最好的为3%双戊烯(DP)＋1.5%氮酮(azone)，然后依次是3%DP、3%薄荷醇(M)、1.5%DP＋1.5%M、2%azone。