反义寡核苷酸抑制早期生长反应基因-1表达对内皮细胞缺氧复氧损伤的影响

目的: 研究反义寡核苷酸(antisense oligodeoxynucleotides,AS-ODN)抑制早期生长反应基因1(early growth response gene-1,Egr-1)表达对内皮细胞缺氧复氧(anoxia/reoxygenation,A/R)损伤的影响。方法: 采用新生大鼠进行心脏微血管内皮细胞(cardiac microvascular endothelial cells,CMECs)原代培养,取3~4代的CMECs建立缺氧复氧模型。细胞随机分为6组:对照(Con)组、缺氧复氧组(A/R)、溶剂组(LIP)、反义寡核苷酸转染组(AS)、正义寡核苷酸转染组(S)和错配寡核苷酸转染组(Sc)。通过测定细胞培养上清液中乳酸脱氢酶(LDH)及内皮细胞中超氧化物歧化酶(SOD)、丙二醛(MDA)含量,观察内皮细胞损伤程度;应用ELISA法测定细胞培养上清液肿瘤坏死因子-α(TNF-α)的含量,观察内皮细胞炎症反应水平;Western-blot法检测培养内皮细胞中Egr-1的蛋白表达水平;显微镜下观察细胞形态学改变并计算存活率。结果: A/R造成内皮细胞内MDA升高,SOD下降,上清液中LDH、TNF-α含量升高,A/R刺激下细胞Egr-1的蛋白表达水平明显升高;A/R刺激前给予AS-ODN可抑制Egr-1蛋白的表达,减轻内皮细胞的损伤及炎症反应程度,提高细胞存活率。结论: AS-ODN抑制培养内皮细胞Egr-1的表达,并降低A/R损伤,提示Egr-1与缺氧复氧所致的心脏微血管内皮细胞损伤密切相关。     

新的四氢异喹啉类化合物CPUE1逆转K562 A02 细胞的多药耐药性

目的 研究新的四氢异喹啉类化合物CPUE1逆转K562/A02 细胞多药耐药性的作用及机制。 方法 在CPUE1 的作用下, 用MTT 法检测长春新碱(vincristine, VCR) 对K562/A02 多药耐药细胞的细胞毒作用的变化, 使用DNA 分析和Annexin-Ⅴ/PI 双染法研究CPUE1 对VCR 诱导K562/A02 细胞凋亡的影响, 流式细胞仪检测CPUE1 对P-糖蛋白(P-glycoprotein,P-gp) 外排罗丹明123 (rhodamine123, Rh123)的作用。 结果 CPUE1 能明显提高VCR 对K562/A02多药耐药细胞的细胞毒作用以及凋亡诱导作用,10 μmol·L^-1的CPUE1 能使K562/A02 对VCR 的IC₅₀值由60.54 μmol·L^-1 降至4.17 μmol·L^-1。CPUE1还能抑制Rh123 外排从而增加细胞内Rh123 的蓄积浓度。 结论 CPUE1 通过抑制P-gp 的活性逆转K562/A02 细胞的多药耐药性。     

A contribution to the crystallochemistry of ternary 1:1:1 and 1:1:2 rare earth intermetallic phases with Pb and Pd

The ternary alloys of the rare earths with lead and palladium were studied for the stoichiometric ratios 1:1:1 and 1:1:2 with respect to the structure of these alloys and their existence field. RPbPd (R = La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Y, Ho, Er, Tm, Yb) compounds have a hexagonal structure, hP9 Fe₂P type, while RPbPd₂ (R = Pr, Sm, Gd, Tb, Dy, Ho, Er, Yb) alloys have the cubic AlCu₂Mn-type structure (cF16, BiF₃ superstructure).     

Corrosion inhibition of mild steel in 1 M HCl solution by henna extract: A comparative study of the inhibition by henna and its constituents (Lawsone, Gallic acid, α-d-Glucose and Tannic acid)

The inhibitive action of henna extract (Lawsonia inermis) and its main constituents (lawsone, gallic acid, α-d-Glucose and tannic acid) on corrosion of mild steel in 1 M HCl solution was investigated through electrochemical techniques and surface analysis (SEM/EDS). Polarization measurements indicate that all the examined compounds act as a mixed inhibitor and inhibition efficiency increases with inhibitor concentration. Maximum inhibition efficiency (92.06%) is obtained at 1.2 g/l henna extract. Inhibition efficiency increases in the order: lawsone > henna extract > gallic acid > α-d-Glucose > tannic acid. Also, inhibition mechanism and thermodynamic parameters are discussed.     

Triode plasma nitriding and PVD coating: A successful pre-treatment combination to improve the wear resistance of DLC coatings on Ti6Al4V alloy

Diamond-like carbon (DLC) coatings have found great applicability in the automotive industry because of their low friction coefficient and high wear resistance. Nevertheless, their tribological performance can be greatly reduced on soft substrates such as titanium alloys. The hard DLC coating cannot usually follow elastic and plastic deformation of the substrate without failing. In order to overcome this property mismatch between hard coating and soft substrate, triode plasma nitriding was applied as a pre-treatment to improve the mechanical properties of the Ti6Al4V alloy and further enhance the load support for the DLC coating. DLC and multilayered TiN/DLC, CrN/DLC CrAlN/DLC coatings were deposited onto “standard” and plasma nitrided Ti6Al4V substrates. Triode plasma nitriding increased the load-bearing capacity of the coating/substrate system, as higher critical adhesion loads were recorded for DLC coatings on plasma nitrided Ti6Al4V substrates. This treatment also reduced the wear rate of the DLC coating/substrate. Further load support and lower wear rates were achieved by using TiN, CrN and CrAlN as intermediate layers on plasma nitrided Ti6Al4V substrates.