Increased Müller cell density during diabetes is ameliorated by aminoguanidine and ramipril

Background: The Müller cell, the major glial cell in the retina, may be important in diabetes. The purpose of this project was to examine the localisation of glutamine synthetase in control and diabetic Müller cells and to determine whether the number of Müller cells is altered during diabetes. We also examined whether two experimental treatments of diabetes, aminoguanidine and ramipril, ameliorated these changes. Methods: Normal Sprague‐Dawley rats rendered diabetic by a single injection of streptozotocin (50 mg/kg) were treated with either aminoguanidine, ramipril or standard water. Following 12 weeks, animals were sacrificed, their eyes removed and the retinae processed for glutamine synthetase immunocytochemistry. The level of glutamine synthetase was quantified in control and diabetic animals and the number of Müller cells counted for each of the treatment groups. Results: In all retinae examined, glutamine synthetase labelled Müller cells along their entire cellular extent and endfeet were more intensely labelled. Following 12 weeks of diabetes, there was a small increase in the level of glutamine synthetase labelling in somata and endfeet compared with controls (ANOVA, P < 0.05). The number of Müller cells was increased following 12 weeks of diabetes (ANOVA, P < 0.0001). This effect was ameliorated by treatment with ramipril and aminoguanidine. Conclusions: These data suggest that Müller cells are altered in number following 12 weeks of diabetes. Moreover, the two experimental treatments were beneficial in preventing this change in Müller cells. Further work is required to establish the mechanisms underlying the change to Müller cells during diabetes.     

A Bar Code and Radio-Frequency Identification System for Transfusion Safety

This presentation will describe a pilot study of radio-frequency (RF) identification tags ("chips") that was conducted in parallel with standard procedures for the collection and testing of Red Blood Cells (Greater Chesapeake and Potomac Region, American Red Cross Biomedical Services, Baltimore, MD) and transfusion (Georgetown University Hospital, Washington, DC). The purpose of the study was to evaluate whether multi-write RF chips could be attached to blood bags, programmed, and used to facilitate the collection of information from (1) a blood bag manufacturer to (2) a blood collection center and, subsequently, to (3) a hospital transfusion service.     

脊髓损伤后神经细胞黏附分子的表达

目的:观察大鼠脊髓损伤后神经细胞黏附分子的表达,分析其与神经修复的关系。方法:实验于2006-02/05在兰州大学第二附属医院骨科研究所完成。成年雄性Wistar大鼠36只,分为空白对照组(n=3)、假手术组(n=3)和损伤组(n=30)。损伤组采用Allen法制成急性外伤模型。分别于术后1,3,5,7,10d麻醉下处死。假手术组仅实施手术不行打击,空白对照组不做任何处理,均在实验初处死。对各组大鼠在处死前以改良的Tarlov评分检测行为及肢体运动功能,观察伤后各时相点大鼠后肢的活动、肌力等,以此评定损伤后大鼠运动功能的恢复情况。测量各组各时间点脊髓灰质中阳性反应细胞并测其灰度值,用免疫组织化学的方法测定脊髓片神经细胞黏附分子的表达。结果:纳入动物数量为36只,损伤组死亡4只,最终进入结果分析32只。①损伤组脊髓损伤后1d改良的Tarlov评分低于空白对照组和假手术组(P<0.01),损伤后10d高于损伤后1d(P<0.01),但评分仍低于假手术组(P<0.01)。②损伤后1d肉眼可见脊髓组织肿胀明显,软脊膜紧绷。光镜下可见中心灰质血管破裂。白质神经纤维水肿,轴突与髓鞘之间间隙增大,1d后肿胀逐渐加重。损伤5d后脊髓肿胀逐渐消退,10d后轴突及髓鞘已退变成空泡。③空白对照组、假手术组脊髓灰质神经细胞黏附分子的表达甚少,损伤组1,3,5,7,10d表达增加,与空白对照组、假手术组比较,差异有显著性意义[(175.38±4.51),(163.15±5.98),(196.28±6.57),(217.42±2.36),(228.36±2.62),(248.31±3.47)(245.28±3.87),P<0.01]。结论:脊髓损伤后神经细胞黏附分子表达增加,提示神经细胞黏附分子可能参与损伤后神经的修复。     

睡眠剥夺对力竭运动大鼠胸腺谷胱甘肽、丙二醛、超氧化物歧化酶的影响

目的:观察不同睡眠剥夺时间后力竭运动对大鼠胸腺谷胱甘肽、丙二醛含量和超氧化物歧化酶活性的变化,探讨睡眠剥夺对大鼠抗氧化能力的影响。方法:实验于2006-04/05在湖南师范大学体育学院运动生物化学实验室完成。实验分组:选择10周龄健康雄性SD大鼠30只,按随机数字表法分为5组,每组6只:睡眠非运动组,睡眠 力竭运动组和睡眠剥夺24,48,72h 力竭运动组。实验方法:①采用轻柔刺激法制备大鼠睡眠剥夺模型。②睡眠非运动组和睡眠 力竭运动组不进行睡眠剥夺。③睡眠 力竭运动组和睡眠剥夺各组大鼠运动方案:跑台坡度为10°,速度为19.3m/min(相当于76%VO2max),所有大鼠运动至力竭(运动末期,大鼠先后滞留跑道后1/3处达3次以上,各种刺激驱赶均无效,停跑后体征表现为呼吸急促,神情倦怠,腹卧位,对刺激反应迟钝,捕捉时,逃避反应较运动前减弱)。实验评估:①大鼠一般状态。②力竭时间。③大鼠力竭后麻醉处死,测定胸腺谷胱甘肽、丙二醛含量和超氧化物歧化酶活性。结果:纳入大鼠30只,均进入结果分析。①大鼠一般状态:睡眠 力竭运动组大鼠表现为形态正常,活泼好动,皮毛光亮,眼睛有神;睡眠剥夺48,h 力竭运动组大鼠均出现神态倦怠,眼神黯淡,四肢亦有不同程度的红肿;睡眠剥夺24h 力竭运动组大72鼠介于以上两者之间。②睡眠 力竭运动组和睡眠剥夺24,7248,h组大鼠的力竭时间分别为(232.36±37.67),(269.19±38.61),(162.42±35.70),(141.07±28.56)。③谷胱甘肽含量、超氧化物歧化酶活性:睡眠 力竭运动组谷胱甘肽含量和超氧min化物歧化酶活性均低于睡眠非运动组[分别为(25.54±0.79),(27.09±1.31)mg/g;(±0.21),(±0.10)mkat/g],差异有显4.594.88著性意义(P<0.05);睡眠剥夺24h 力竭运动组谷胱甘肽含量和超氧化物歧化酶活性均高于睡眠非运动组[分别为(28.60±0.96),(27.09±1.31)mg/g;(±0.10),(±0.10)5.234.88mkat/g],差异有显著性意义(P<0.05),睡眠剥夺48,h 力竭运动组P72均低于睡眠非运动组[分别为(23.74±1.19),(22.43±0.52),(27.09±1.31)mg/g;(±0.14),(±0.18),(±0.10)mkat/g],4.523.354.88差异均有非常显著性意义(P<0.01);睡眠剥夺各组与睡眠 力竭运动组间谷胱甘肽含量和超氧化物歧化酶活性差异均有非常P显著性意义(P<0.01);睡眠剥夺各组间比较差异有显著性意义(P<0.05)。④丙二醛浓度:睡眠 力竭运动组丙二醛浓度高于P睡眠非运动组[分别为(±0.27),(±0.24)μmol/L],差异有非常显著性意义(P<0.01);睡眠剥夺各组与睡眠非运动组之间6.565.35P差异均有非常显著性意义(P<0.01);睡眠剥夺24,48,72h 力竭运动组丙二醛含量均高于睡眠 力竭运动组[分别为(±0.12),(±P7.398.850.72),(10.89±0.82),(±0.27)μmol/L],差异有显著性意义(P<0.05;P<0.01);睡眠剥夺各组间比较,睡眠剥夺48h与睡眠剥夺24h差6.56异无显著性意义(P>0.05),睡眠剥夺72h与睡眠剥夺24h、睡眠剥夺72h与睡眠剥夺48h间比较差异有非常显著性意义(P<0.01)。结论:①睡眠剥夺24h可引起大鼠胸腺氧化应激,使氧自由基能力有所增强。②睡眠剥夺48,72h力竭运动后氧自由基能力降低。     

关节软骨脱细胞支架材料的制备

目的:探讨脱细胞关节软骨支架材料的制备方法,制备软骨理想的组织工程支架材料。方法:实验于2005-12/2006-08在兰州大学第二医院骨科研究所实验室完成。实验方法:利用冷冻干燥、化学去污剂等方法制备脱细胞的兔关节软骨。在无菌状态下取青紫蓝兔的新鲜兔关节软骨,剪成3.5mm×3.5mm,厚度0.2～2.0mm,在冷冻干燥器中冻干12h。在10g/L Triton X-100、Tris-HCl液内加入蛋白酶抑制剂-苯甲基黄酰氟,持续振荡48h后标本以双蒸馏水连续冲洗后置于DNase I酶和RNase A酶混合液中消化。置于10g/L Triton X-100、Tris-HCl液中洗脱。实验评估:①大体观察:肉眼观察脱细胞后关节软骨的外观形态。②组织学观察:将制备的脱细胞关节软骨行石蜡包埋切片,行苏木精-伊红染色、Massion三色染色并在光镜下观察。③扫描电镜观察:将制备的脱细胞关节软骨以戊二醛-锇酸双固定后,行扫描电镜观察。结果:①脱细胞后关节软骨外观形态:肉眼下可见正常关节软骨呈白色或淡黄色,脱细胞后关节软骨色呈灰白,半透明状,无光泽,外形与软骨相似并且仍维持了关节软骨的结构。②脱细胞后关节软骨的组织学变化:苏木精-伊红染色显示,软骨细胞消失,软骨巢分辨不清,在巢内没有蓝染的核物质,核细胞碎屑,只有红染为残留的细胞外基质。Massion三色染色显示,脱细胞后关节软骨内主要含有胶原纤维。③脱细胞后关节软骨的超微结构:扫描电镜下显示,脱细胞后关节软骨陷窝呈蜂窝状,未见到残余的细胞核、细胞器,残余的空穴高低不平。结论:经冷冻干燥、化学去污剂等方法可完整去除软骨中的细胞成分,保留胶原纤维等细胞外基质。     

White cells protect donor blood against bacterial contamination

The possible beneficial role of white cells (WBCs) in donor blood has been investigated with respect to their capacity to remove bacteria. Preparations of buffy coat and whole blood, containing as well as reduced of WBCs, were inoculated with Staphylococcus epidermidis, S. aureus, Escherichia coli, Pseudomonas aeruginosa, and Propionibacterium species. Upon storage at room temperature, the presence of WBCs resulted in a reduction of the bacterial content. Units inoculated with S. epidermidis and E. coli were completely cleared of bacteria within 5 to 24 hours. On the other hand, S. aureus, after an initial reduction in number, started to multiply. In WBC-reduced units, the initial bacterial content remained unchanged for 5 hours, but the bacteria then exhibited vigorous growth within 48 hours in buffy coat and slower growth in whole blood. Propionibacterium sp. did not grow with or without WBCs. P. aeruginosa did not grow in buffy coat but showed a growth pattern similar to that of S. aureus in whole blood. The presence of WBCs in the donor blood during the first hours after collection thus seems to rid the blood of at least some species of bacteria. These results indicate that it would be favorable not to perform WBC reduction during blood collection and that several hours of contact can be needed to obtain sterility.     

Inducible nitric oxide synthase (iNOS) expression in monocytes during acute Dengue Fever in patients and during in vitro infection

 

Mononuclear phagocytes are considered to be main targets for Dengue Virus (DENV) replication. These cells are activated after infection, producing proinflammatory mediators, including tumour-necrosis factor-α, which has also been detected in vivo. Nitric oxide (NO), usually produced by activated mononuclear phagocytes, has antimicrobial and antiviral activities.

Methods

The expression of DENV antigens and inducible nitric oxide synthase (iNOS) in human blood isolated monocytes were analysed by flow cytometry using cells either from patients with acute Dengue Fever or after DENV-1 in vitro infection. DENV-1 susceptibility to iNOS inhibition and NO production was investigated using N^G-methyl L-Arginine (N^GMLA) as an iNOS inhibitor, which was added to DENV-1 infected human monocytes, and sodium nitroprussiate (SNP), a NO donor, added to infected C6/36 mosquito cell clone. Viral antigens after treatments were detected by flow cytometry analysis.

Results

INOS expression in activated monocytes was observed in 10 out of 21 patients with Dengue Fever and was absent in cells from ten healthy individuals. DENV antigens detected in 25 out of 35 patients, were observed early during in vitro infection (3 days), significantly diminished with time, indicating that virus replicated, however monocytes controlled the infection. On the other hand, the iNOS expression was detected at increasing frequency in in vitro infected monocytes from three to six days, exhibiting an inverse relationship to DENV antigen expression. We demonstrated that the detection of the DENV-1 antigen was enhanced during monocyte treatment with N^GMLA. In the mosquito cell line C6/36, virus detection was significantly reduced in the presence of SNP, when compared to that of untreated cells.

Conclusion

This study is the first to reveal the activation of DENV infected monocytes based on induction of iNOS both in vivo and in vitro, as well as the susceptibility of DENV-1 to a NO production.     

Plasminogen activator inhibitor: a regulator of ancrod-induced fibrin deposition in rabbits

Plasma levels of a fast-acting plasminogen activator inhibitor (PAI), which neutralizes both tissue plasminogen activator (t-PA) and urokinase, are markedly increased in endotoxin-treated rabbits. The ability of this inhibitor to prevent the fibrinolysis that occurs after a thrombogenic stimulus was investigated in a rabbit model. Normal and endotoxin-treated male New Zealand rabbits were infused with ancrod, an enzyme that causes noncrosslinked fibrin formation in vivo. Ancrod stimulated t-PA activity by 90% in normal rabbits and caused hypofibrinogenemia but did not increase PAI levels or induce fibrin deposition in target organs. Rabbits injected with endotoxin (10 micrograms/kg) showed an increase in PAI from less than 1 to 32 U/mL 4 hours later. When ancrod was infused at this time, 90% of the rabbits developed renal fibrin thrombi. Fibrin deposition was recorded in 40% of the rabbits that received a lower dose of endotoxin (1.0 microgram/kg) and had a PAI level of 14 U/ml at the time of ancrod infusion 4 hours later. Fibrin deposition did not occur in the endotoxin-treated rabbits that received normal saline. These data suggest that high levels of PAI inhibit fibrinolysis in vivo, thereby promoting fibrin clot deposition following a thrombogenic stimulus.