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81.
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目的探讨亚低温和高温对内毒素致急性肺损伤(ALI)大鼠肺微血管通透性的影响。方法健康雄性SD大鼠48只,体重300~350 g,随机分为4组(n=12),常温对照组(A组)静脉注射37℃生理盐水;常温内毒素组(B组)静脉注射脂多糖(LPS)5 mg·kg-1;亚低温 内毒素组(C组)静脉注射LPS 5 mg·kg-1,维持直肠温31.5~32℃;高温 内毒素组(D组)静脉注射LPS 5 mg·kg-1,维持直肠温39.5~40℃。动脉血氧合指数(PaO2/FiO2)≤300 mm Hg即ALI模型制备成功。于ALI 6 h后处死大鼠,取肺组织,清洗固定后测定肺微血管通透性指标:肺湿/干重量比(W/D)、肺泡灌洗液(BALF)蛋白(BALFpro)、肺通透性指数(PPI)、肺微血管通透性指数(PMPI)及肺组织硝基酪氨酸(NT)、髓过氧化物酶(MPO)、丙二醛(MDA)含量,观察肺组织病理学改变。结果与A组比较,B组、C组、D组PPI、W/D、BALFpro、PMPI和肺组织MPO、MDA、NT均升高(P<0.05);与B组比较,C组上述指标降低,D组上述指标升高(P<0.05);与C组比较,D组PPI、W/D、BALFpro、PMPI和肺组织MPO、MDA、NT升高(P <0.05)。结论高温加重内毒素血症大鼠ALI程度,亚低温通过抑制ONOO-生成,抑制了肺微血管通透性的升高,可减轻大鼠内毒素致ALI。 相似文献
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YuriL. Lyubchenko LudaS. Shlyakhtenko 《Proceedings of the National Academy of Sciences of the United States of America》1997,94(2):496-501
Tertiary structure of supercoiled DNA is a significant factor in a number of genetic functions and is apparently affected by environmental conditions. We applied atomic force microscopy (AFM) for imaging the supercoiled DNA deposited at different ionic conditions. We have employed a technique for the sample preparation that permits high-resolution AFM imaging of DNA bound to the surface in buffer solutions without drying the sample (AFM in situ). The AFM data show that at low ionic strength, DNA molecules are loosely interwound supercoils with an irregular shape. Plectonemic superhelices are formed in high-concentration, near-physiological salt solutions. At such ionic conditions, superhelical loops are typically separated by regions of close helix–helix contacts. The data obtained show directly and unambiguously that overall geometry of supercoiled DNA depends dramatically on ionic conditions. This fact and the formation of close contacts between DNA helices are important features of supercoiled DNA related to its biological functions. 相似文献
85.
DNA bending induced by Cro protein binding as demonstrated by gel electrophoresis. 总被引:10,自引:5,他引:5 下载免费PDF全文
Y Lyubchenko L Shlyakhtenko B Chernov R E Harrington 《Proceedings of the National Academy of Sciences of the United States of America》1991,88(12):5331-5334
We report an approach for studying protein-induced DNA bends in solution that is based on measuring the sizes of circular DNA molecules by using two-dimensional gel electrophoresis. These circular fragments are obtained by ligating short synthetic oligonucleotides containing a protein-recognition region in the presence of protein. Oligonucleotides 21-base-pairs-long containing the OR3 recognition site were synthesized and ligated in both the presence and the absence of the Cro repressor from lambda phage. We show that in the presence of Cro protein, circular DNA molecules are formed with substantial frequency. No circular molecules are observed in the DNA samples ligated in the absence of Cro. These experiments clearly demonstrate that DNA bending is induced by Cro in this operator site. The sum of inherent plus Cro-induced bending is estimated as 45 degrees. 相似文献
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We examined the effects of co-incubating nine different Abeta peptide fragments with full-length Abeta1-40 (Abeta40) on protein aggregation. Six fragments enhanced aggregation of Abeta40 (Abeta1-28, 12-28, 17-28, 10-20, 25-35 and 17-40), while three others did not (Abeta1-11, 1-16, and 20-29). All of the peptides that enhanced aggregation contained either residues 17-20 or 30-35, indicating the importance of these regions for promoting aggregation of full-length Abeta. Abeta25-35 in particular increased both the rate and extent of aggregation of Abeta40 considerably as indicated by fluorescence staining. Atomic force microscope imaging (AFM) indicates the increase in fluorescence staining with Abeta25-35 is primarily due to increased formation of oligomers and protofibrils rather than formation of large amyloid fibrils. AFM images of Abeta25-35 when incubated alone also indicate formation of aggregates and long thin filaments. The increase in formation of the small toxic oligomeric morphology of Abeta40, along with formation of Abeta25-35 oligomers and thin filaments, represent two different potential pathways for Abeta25-35 toxicity. The critical roles of residues 17-20 and 30-35 of Abeta provide further insight into mechanism that underlie the formation of toxic aggregates in Alzheimer Disease (AD) and suggest targets for the design of beta-sheet breakers to modulate the aggregation and inhibit toxicity of full-length Abeta. 相似文献
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Urologic complications following renal transplantation: role of interventional radiologic procedures 总被引:1,自引:0,他引:1
Bennett LN; Voegeli DR; Crummy AB; McDermott JC; Jensen SR; Sollinger HW 《Radiology》1986,160(2):531-536
Seventy renal transplant recipients with suspected urologic problems underwent interventional radiologic procedures for further diagnosis and treatment. We found that 28 patients did not have urologic complications. The other 42 patients demonstrated a total of 62 complications, including 40 cases of obstruction, 12 cases of extravasation, and ten collections of pararenal fluid. Ultrasound and nuclear renal scans with both technetium-99m DTPA and iodine-131 hippuran were found to be sensitive screening techniques for the detection of these complications. Fifty of the 51 abnormalities were detected using a combination of these techniques. Percutaneous methods alone were successful in treating 15 urinary obstructions, eight pararenal fluid collections, and five urinary extravasations. We encountered six procedure-related complications, and there were three delayed infectious complications that were related to indwelling nephrostomy tubes. One of these three complications resulted in death. The results of our study suggest that invasive radiologic procedures can be safely used to diagnose and treat urologic complications in renal transplant recipients. 相似文献
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