^(99m)Tc-硫胶体监测移植肾后急性排异的再评价

目的 :重新评估99mTc 硫胶体 ( 99mTc SC)显像在移植肾急性排异方面的临床价值 ;分析误诊原因 ;改进方法 ,以提高诊断的准确性。材料和方法 :对 14 0例移植肾患者的99mTc SC显像进行回顾性分析 ;为避免骨髓影像的干扰 ,在常规方法的基础上建立镜相法 ,并对其中 2 0例显像作镜相法和常规法的对比研究。结果 :99mTc SC显像 (常规法 )诊断急性排异的灵敏性 84 8% ,特异性 80 0 % ,准确性 82 1% ;使用OKT3 的患者的假阳性的发生率明显高于对照组。结论 :虽然OKT3增加了假阳性的发生率 ,但99mTc SC显像仍是目前鉴别诊断移植肾急性排异和急性肾小管坏死的最佳方法 ;镜相法尚无法替代常规法 ,但可作为常规法的有效辅助手段。

Characteristic evaluation of Al_2O_3/CNTs hybrid materials for micro-electrical discharge machining

The characteristic evaluation of aluminum oxide （A1203）/carbon nanotubes （CNTs） hybrid composites for micro-electrical discharge machining （EDM） was described. Alumina matrix composites reinforced with CNTs were fabricated by a catalytic chemical vapor deposition method. A1203 composites with different CNT concentrations were synthesized. The electrical characteristic of A1203/CNTs composites was examined. These composites were machined by the EDM process according to the various EDM parameters, and the characteristics of machining were analyzed using field emission scanning electron microscope （FESEM）. The electrical conductivity has a increasing tendency as the CNTs content is increased and has a critical point at 5% A1203 （volume fraction）. In the machining accuracy, many tangles of CNT in A1203/CNTs composites cause violent spark. Thus, it causes the poor dimensional accuracy and circularity. The results show that conductivity of the materials and homogeneous distribution of CNTs in the matrix are important factors for micro-EDM of A1203/CNTs hybrid composites.

Study on microscale adhesion between solid surfaces with scanning probe

The adhesion between two parallel solid surfaces is of great interest with the rapid development of micro-nano devices and instruments.The adhesion forces between a flat tip with a diameter^1.7μm and some surface have been determined by recording the force-displacement curves with an atomic force microscope(AFM).The flat tip is used to prevent wear and mimic the adhesion between two parallel surfaces.The free energy of the solid surface is calculated by the contact angles between the probe liquids and the surface.The adhesion force between parallel solid surfaces cannot be predicted by the theory of thermodynamic surface free energy.The adhesion measurements were carried out under ambient conditions,in a nitrogen-filled glove box,under distilled water,and under potassium chloride(KCl)solution.The outcome shows that the real contact area without the applied load is only a small proportion of the apparent contact area.The measurement stability and repeatability of adhesion by the AFM depend on the surface characterization,measurement methods and the environment.Under different environments,there are different interactions and factors affecting the adhesion force,and the dominant interactions and factors may be different too.The various interactions and factors are mutually coupled to determine the final adhesion force.

Protective effect of Sijunzi decoction on neuromuscular junction ultrastructure in autoimmune myasthenia gravis rats

OBJECTⅣE: To investigate the protective role of Sijunzi decoction in neuromuscular junction(NMJ)and muscle cell mitochondria ultrastructure; as well as its effects on the amount of adenosine triphosphate(ATP) and the activities of mitochondrial respiratory chain complexes I, Ⅱ, Ⅲ, and Ⅳ in autoimmune myasthenia gravis rats.METHODS: An experimental autoimmune myasthenia gravis(EAMG) rat model was established by inoculating rats with acetylcholine receptors extracted from Torpedo. Rats were divided into three groups: model, prednisone, and Sijunzi decoction, and were fed physiological saline, prednisone, or Sijunzi decoction, respectively. NMJ and muscle cell mitochondria ultrastructure were observed by transmission electron microscope. The amount of ATP was assessed by high performance liquid chromatography. The activities ofmitochondrial respiratory chain complexes I, Ⅱ, Ⅲ,and Ⅳ was determined using the Clark oxygen electrode method.RESULTS: In the model group, there were sparse muscle fibers, with decreased mitochondria, and sparse, diffluent, or absent NMJ folds. After intervention with Sijunzi decoction, the above pathology changes were improved: muscle fiber structure was clear and complete; the mitochondria count was higher; and the NMJ structure was close to normal. Gastrocnemius muscle mitochondria in the model group produced significantly less ATP than those in the prednisone group(P<0.01). Conversely, the ATP of Sijunzi decoction group was significantly higher than prednisone group(P<0.01). The activities of gastrocnemius muscle mitochondrial respiratory chain complexes I, Ⅱ, Ⅲ, and Ⅳ in both the prednisone and Sijunzi decoction groups was dramatically higher compared with the model group(P<0.05). The activities of complexes I and Ⅲ in the Sijunzi decoction group were significantly higher than those in the prednisone group(P<0.05), but there was no obvious difference in complex Ⅱ or Ⅳ activities between the two groups(P>0.05).CONCLUSION: Sijunzi decoction improved pathological changes in muscle mitochondria and NMJ,enhanced the amount of ATP in gastrocnemius muscle mitochondria, and improved the activities of respiratory chain complexes I, Ⅱ, Ⅲ, and Ⅳ(especially I and Ⅲ) of the EAMG rats.

Comparison of microwave-assisted extraction of aloe-emodin in aloe with Soxhlet extraction and ultrasound-assisted extraction

This paper reports the extraction of aloe-emodin from aloe by microwave-assisted extraction. The effects of various factors, including the solvent, the ratio （mL/g） of the solvent to the sample, microwave irradiation time and microwave power, were discussed in the experiments. The yield of aloe-emodin was determined by HPLC. The optimized conditions for micro- wave-assisted extraction of aloe-emodin were concluded as follows： the solvent is 80% ethanol （V/V） solution, microwave ir- radiation time is 3 rain and microwave power is 340 W. Additionally, HPLC fingerprint was developed for consistency evalua- tion of aloe. The similarities of 3 aloe samples obtained by microwave-assisted extraction, ultrasound-assisted extraction and Soxhlet extraction were more than 0.9, indicating that 3 aloe samples were consistent. Compared with Soxhlet extraction and ultrasound-assisted extraction, microwave extraction is a rapid method with higher yield and less solvent consumption. Aloe samples treated by microwave-assisted extraction, ultrasound-assisted extraction and Soxhlet extraction were observed using transmission electronic microscopy. The micrographs provide evidence of more breakage of chloroplasts treated by micro- wave-assisted extraction as compared to Soxhlet extraction and ultrasound-assisted extraction.