马钱子碱纳米微粒抗肝细胞癌作用的实验研究

目的 观察马钱子碱纳米微粒的抗肝细胞癌作用.方法 采用超声乳化法研制羧基化聚乙二醇-聚乳酸嵌段共聚物马钱子碱纳米微粒,体外观察其对肝癌细胞SMMC-7721生长的影响;采用Western blotting和FQ-PCR检测药物作用72 h对肝癌细胞凋亡相关蛋白Fas蛋白和mRNA表达水平的影响.结果 马钱子碱纳米微粒平均粒径(146±96) nm,载药率:4.2％,包封率:67％.随药物浓度的增加,肝癌细胞生长抑制作用明显,呈现剂量依赖性.5-FU、马钱子碱和马钱子碱纳米微粒对肝癌细胞生长的IC50分别为16.7 μg/ml、90.3 μg/ml和164.9 μg/ml,三者之间差异显著(P＜0.05).与空白纳米微粒相比,马钱子碱纳米微粒显著诱导肝癌细胞Fas蛋白和mRNA表达,且320 μg/ml剂量诱导表达显著高于160 μg/ml (P＜0.05).结论 马钱子碱纳米微粒显著抑制肝癌细胞生长,诱导肝癌细胞凋亡,可能与上调肝癌细胞Fas蛋白和mRNA表达有关.马钱子碱纳米微粒是一种具有潜在发展前景的肝癌治疗药物.     

Solid-phase peptide synthesis at elevated temperatures: a search for an optimized synthesis condition of unsulfated cholecystokinin-12

A systematic investigation of solid-phase peptide synthesis at elevated temperatures using the well-known aggregating peptide acyl carrier protein (65–74) and the unsulfated cholecystokinin-8 as models is presented. The main goal of the investigation was the determination of an optimized experimental condition for the synthesis of unsulfated cholecystokinin-12. Of the elevated temperatures used, 60°C was the most appropriate. The efficiency of N, N'-diisopropylcarbodiimide/l-hydroxybenzotriazole (DIC/HOBt) in 25% dimethyl sulfoxide (DMSO)/toluene at this temperature was similar to that of 2-(1-H-benzotriazole-1-yl)-1, 1, 3, 3-tetramethyluronium tetrafluoroborate (TBTU). Interestingly, this coupling reagent was more efficient than TBTU, benzotriazol-1-yl oxy-tris(dimethylamino)phosphonium and O-(7-azabenzotriazol-1-yl)-1, 1, 3, 3-tetramethyluronium hexafluorophosphate in N-methylpyrrolidone. 25%DMSO/toluene proved to be suitable for the swelling of the resins phenylacetamidomethyl, methylbenzhydrylamine, hydroxymethylphenoxy, 4-(benzyloxy)-2′, 4′-dimethoxybenzhydrylamine, 4-(2′, 4′-dimethoxyphenyl-Fmoc-aminomethyl)phenoxy and (4-succinylamido-2′, 2′, 4′-trimethoxy)benzhydrylamine. Those polymeric supports were fully compatible with the approach. Under the optimized synthesis condition found in these studies (temperature of 60°C, DIC/HOBt as coupling reagent and 25%DMSO/toluene as solvent), no difficulties related to the aggregation phenomenon were encountered. These data confirm the usefulness of solid-phase peptide synthesis at elevated temperatures and extend its applicability.     

Airflow measurement inaccuracies in aerosol imaging

Aerosol production using inclined compressed air tanks may be subject to error caused by airflow meter variability and by the degree of inclination of the air-flow meter. Since most of these tanks are used in an inclined position, it is important for clinicians to be aware of these errors.     

Transoral approach to the cervical spine: report of four cases

The transoral approach to the upper cervical spine is an established but little used route, offering excellent access with good wound healing, to lesions of the bodies of the atlas, axis and upper part of the third cervical vertebra. The authors report four cases which demonstrate the value of the procedure.     

Transcatheter embolization of coronary artery fistula with controlled release coils

ABSTRACT The treatment for large congenital coronary cameral fistulas has been surgical but with advances in interventional catheterization techniques transcatheter embolization of these fistulas with coils or detachable balloons is now possible. This report describes occlusion of a congenital coronary arteriovenous fistula in a 6-year-old girl.