A new stent with streamlined cross-section can suppress monocyte cell adhesion in the flow disturbance zones of the endovascular stent

We proposed a new stent with streamlined cross-sectional wires, which is different from the clinical coronary stents with square or round cross-sections. We believe the new stent might have better hemodynamic performance than the clinical metal stents. To test the hypothesis, we designed an experimental study to compare the performance of the new stent with the clinical stents in terms of monocyte (U-937 cells) adhesion. The results showed that when compared with the clinical stents, the adhesion of U-937 cells were much less in the new stent. The results also showed that, when Reynolds number increased from 180 (the rest condition for the coronary arteries) to 360 (the strenuous exercise condition for the coronary arteries), the flow disturbance zones in the clinical stents became larger, while they became smaller with the new stent. The present experimental study therefore suggests that the optimization of the cross-sectional shape of stent wires ought to be taken into consideration in the design of endovascular stents.     

Properties of biocomposites based on lignocellulosic fillers

This paper is focused on the analysis of the thermal and mechanical behaviour of processed biocomposites (biodegradable composites). These materials have been created by extrusion and injection moulding. The matrix, a biodegradable and aromatic copolyester (polybutylene adipate-co-terephthalate), has been fully characterised (NMR, SEC). The lignocellulosic materials used as fillers are a by-product of an industrial fractionation process of wheat straw. Different filler fractions have been selected by successive sieving, and then carefully analysed (granulometry, chemical structure). Cellulose, lignin, and hemicellulose contents have been determined through different techniques. The biocomposites thermal behaviour has been investigated by TGA (thermal degradation) and DSC (transition temperatures, crystallinity). These materials present good mechanical behaviour due to high filler-matrix compatibility. The impacts of filler content, filler size and the nature of each fraction have been analysed. To predict the mechanical behaviour, Takayanagi’s equation seems to provide an accurate answer to evaluate the modulus in a range, 0–30 wt% of fillers.     

血管内支架和支架内皮化

简要介绍了血管内支架产生的背景、发展进程及其应用于临床后出现的再狭窄问题,着重综述了十几年来内皮细胞种植血管内支架预防术后再狭窄的相关研究成果。血管内支架内皮化的最终实现可以使现行的血管支架具有正常血管内皮的生物相容性及生理功能,是控制支架植入术后再狭窄问题的很有前途的支架改进方法。     

Fungal degradation of carbohydrate-linked polystyrenes

A series of carbohydrate molecules like glucose, sucrose and lactose were linked to maleic anhydride functionalized polystyrene by polymer analogous reactions to produce biodegradable polymers. Pure culture system was used for evaluating the biodegradability of these sugar linked polystyrene-maleic anhydride copolymers by known fungal test organisms. Weight loss measurements after fungal treatment confirmed the biodegradability of the carbohydrate-linked polymers, and it was observed that the degree of susceptibility to degradation varied with the type of test organism as well as with the type of sugar. FTIR spectra confirmed the degradation of the polymer.     

Biosynthesis of nearly monodispersed poly(ε-<Emphasis Type="SmallCaps">l</Emphasis>-lysine) in <Emphasis Type="Italic">Streptomyces</Emphasis> species

Poly(ε-l-lysine) (ε-PL) is a naturally occurring poly(amino acid) characterized by a unique structure linking ε-amino and carboxyl groups of l-lysine. Due to its various functions and its biodegradability and non-toxicity, the ε-PL polymer has attracted increasing attention in recent years. ε-PL is frequently found in various strains of Streptomyces sp. This review gives an up-to-date overview regarding the biosynthesis of ε-PL focussing mainly on results obtained from ten newly isolated producer strains, using the two-stage culture method of cell growth and ε-PL production cultures. The production of nearly monodispersed ε-PL is covered together with the development of ε-PL specific hydrolases and the release of synthesized ε-PL into the culture broth. From these results, coupled with the termination of polymerization through nucleophilic chain transfer, the biosynthetic mechanism of the polymer is discussed.     

Production of polyhydroxyalkanoate from starch by the native isolate <Emphasis Type="Italic">Bacillus cereus</Emphasis> CFR06

A bacterial strain that produces amylase and polyhydroxyalkanoate (PHA) was isolated, identified, and classified under the Bacillus cereus group based on 16S rRNA gene sequences and specific reaction in poly-myxin egg yolk Mannitol bromothymol blue agar (PEMBA) medium and in combination with microbiological and biochemical tests. The complete ORF of phaC gene was cloned by PCR technique and nucleotide sequences were determined. Results indicated that the phaC gene had 99% homology with phaC of B. cereus (AE016877.1), 98% with B. thuringiensis (AY331151.1), and 94% with several strains of B. anthracis and B. cereus group including Bacillus sp. INT005. However, only 90% sequence homology with phaC of B. megaterium (AF109909.2) was observed. The PHA production using different fermentable sugars was tested and it was found that the CFR06 was able to accumulate 36–60% of PHA in cell dry weight (CDW). Zymogram of amylase indicated that native strain produces an extracellular enzyme of ∼80 kDa. The potency of the organism to hydrolyze starch due to the intrinsic amylase activity was considered, and starch was used as the sole carbon source for growth and PHA production. GC, FTIR, and ¹H NMR analysis of the polymer indicated that the strain was a potent polyhydroxybutyrate (PHB) producer. The bacterium accumulated about 48% PHA in CDW in a starch containing medium.     

利用转基因植物合成生物可降解材料聚羟基脂肪酸酯

聚羟基脂肪酸酯 (polyhydroxyalkanoates,PHAs)因其完全的生物可降解性、良好的物理加工特性以及生物相容性使其应用前途十分广泛。本文综述了利用转基因植物合成PHAs的研究概况和存在问题 ,进一步探讨了其解决方法。     

输尿管支架管在泌尿外科的临床实用价值

目的:总结临床泌尿外科中应用输尿管支架管治疗泌尿系统疾病的优越性以及对其并发症的防治.方法:通过对112例泌尿系统疾病患者在泌尿外科中应用输尿管支架管的临床资料进行回顾性分析,对临床中应用输尿管支架管的疾病类型、手术结果、并发症及其防治方法进行概括性总结.结果:输尿管支架管在临床泌尿系统疾病中以肾及输尿管结石以及尿路梗阻较多(P＜0.05),分别为48例(42.9％)及41例(36.6％);术中输尿管支架管放置均成功,术后常见的并发症主要有膀胱刺激、血尿(P＜0.05),分别为51例(45.5％)及45例(40.2％).结论:输尿管支架管广泛适用于临床泌尿外科,合理的应用可以有效减低并发症的发生率,提高临床使用的有效率.