膜式氧合器中膜材料的研究进展

检索Pubmed数据库和万方数据库以及中国期刊全文数据库文献,分析膜式氧合器的特点.结果表明现在人工肺的应用主要是分离膜式,其形式已从最初的卷筒式、平板折叠式发展到今天广为采用的微孔中空纤维膜式.中空纤维膜氧合器使用中空纤维膜作为交换的主要场所,完成氧气和二氧化碳的交换,由于其在交换面积、氧合形态等方面具有优势,近年来已经成为人工肺研究的主要方向.用于制造中空纤维的材料主要为一些成纤性能良好的高分子材料,对膜材料的要求是具有良好的成膜性、热稳定性、化学稳定性、耐酸碱性、微生物侵蚀性和抗氧化性.当前的研究主要是为了提高气体交换能力和提高生物相容性,采用的方法主要有改进膜材料,优化设计以及对各种性能的实验评估和临床评价.     

Anionic nanoparticle-lipid membrane interactions: the protonation of anionic ligands at the membrane surface reduces membrane disruption

Monolayer-protected gold nanoparticles (Au NPs) are promising biomedical tools with applications in diagnosis and therapy, thanks to their biocompatibility and versatility. Here we show how the NP surface functionalization can drive the mechanism of interaction with lipid membranes. In particular, we show that the spontaneous protonation of anionic carboxylic groups on the NP surface can make the NP-membrane interaction faster and less disruptive.

The interaction between anionic Au nanoparticles and model lipid membranes is facilitated by the spontaneous protonation of the NP ligand carboxylate groups, COO⁻˙ → COOH, in the lipid headgroup region.     

Placental membrane transport

Brush border (microvillous) plasma membranes (BBM) and the basal surfaces (BCM) from the syncytiotrophoblast of human term placenta were prepared by a method of sonication, dialysis and differential centrifugation in specific buffer systems. Such plasma membranes formed closed, osmotically active, right-side-out vesicles in which amino acid transport could be studied unidirectionally by a carefully designed membrane filtration assay under reduced pressure. In such vesicles,l-leucine (1 mM) was found to be transported in a time-dependent manner, peak accumulation being attained at 45 s in both BBM and BCM. The accumulation of leucine in the vesicles was dependent on an inward NaCl gradient, as replacing the Na⁺with K⁺, Li⁺and choline, or replacing the Cl^? with SO ₄ ^2? failed to influence the amino acid movement. Leucine transport in the vesicles also appeared to be dependent on the substrate concentration, indicating saturation at a higher concentration. The transport process showed a k_t (affinity constant) of 3.85 and 6.67 mM, while the values recorded for the J_max (maximum apparent initial velocity) were 270.27 and 384.62 nmol/mg protein^?1 per min in the BBM and BCM respectively. Leucine transport was inhibited by a number of amino acids, among which amino isobutyric acid (AIB) produced the maximum inhibition. The k_i (inhibition constant) for different amino acids has also been listed. Lysine showed the least k_i value, thus showing it to be the most inhibitory compound. These findings are discussed in relation to the mechanism and regulation of transplacental amino acid transfer.     

Extracorporeal membrane oxygenation

PURPOSE OF REVIEW: Extracorporeal membrane oxygenation (ECMO) has become a more or less accepted standard in the algorithm of advanced acute respiratory distress syndrome therapy in adult patients when all other treatment options have failed. This article reviews the current status of ECMO therapy with particular focus on new technical developments and their potential implications for performance and indications for ECMO therapy. RECENT FINDINGS: A recently published review on a single-center experience in 255 adult ECMO patients identified using multivariate logistic regression analysis age, sex, initial pH 7.10 or lower and PaO2/FiO2 ratio, and days of mechanical ventilation before ECMO as a significant predictors of survival. Additionally, a careful cost-effectiveness study for neonatal ECMO relating a 4-year base to the UK neonatal ECMO trial has clearly demonstrated cost-effectiveness. SUMMARY: Over the years, the technique for ECMO therapy underwent substantial changes in indications and the materials used. Impressive technical progress has been made in pumps, oxygenators, and coating of artificial surfaces, leading to a higher biocompatibility and to a lower rate of procedure-related complications. The potential of new inline pumps in combination with a decreasing rate of procedure-related complications might lead to a re-evaluation of the role of extracorporeal lung support in acute respiratory distress syndrome therapy. A very recent development is the use of spontaneous arteriovenous devices for carbon dioxide removal, allowing significant reduction of ventilator settings at decreased carbon dioxide partial pressures and at increased pH values. Ongoing studies are looking at the potential of this approach to reduce side effects of mechanical ventilation further.     

Association between the glycation of erythrocyte membrane proteins and membrane fluidity

Erythrocyte membrane ghosts prepared from normal individuals were incubated in vitro at different glucose concentrations for 72 h. Incubation with increasing concentrations of glucose resulted in increased glycation (nonenzymatic glycosylation) of membrane proteins and a decrease of erythrocyte membrane fluidity measured by the use of the fluorescent label pyrene. It would therefore seem likely that the changes in erythrocyte membrane fluidity previously reported in diabetic subjects (1-3) are related to in vivo glycation of membrane proteins as well as to changes in lipid composition, as was previously suggested (2).     

可降解聚羟基丁酸酯-羟基戊酸酯的共聚物膜

背景：聚羟基丁酸/羟基戊酸共聚酯已用于构建心脏生物瓣膜,但不知是否可作为骨再生引导膜？目的：观察聚羟基丁酸/羟基戊酸共聚酯膜的生物相容性,并评价其成骨能力。方法：采用MTT法检测100%,75%,50%,25%聚羟基丁酸/羟基戊酸共聚酯材料浸提液对犬骨髓间充质干细胞相对增殖度的影响,并评价其细胞毒性;在犬胫骨缺损模型左右两侧远心端骨缺损上方覆盖聚羟基丁酸/羟基戊酸共聚酯膜作为实验组,在近心端仅以骨膜瓣复位作为对照组。结果与结论：100%,75%,50%,25%聚羟基丁酸/羟基戊酸共聚酯膜的细胞毒性分级为0～1级,对骨髓间充质干细胞的生长及增殖无毒性;实验组术后第2周即可见新骨形成,12周时骨缺损区已完全被新骨充填,骨修复质量明显优于对照组。表明聚羟基丁酸/羟基戊酸共聚酯膜具有良好的生物相容性,对骨髓间充质干细胞无明显毒性,引导成骨能力强。     

可降解聚羟基丁酸酯-羟基戊酸酯的共聚物膜(英文)

背景:聚羟基丁酸/羟基戊酸共聚酯已用于构建心脏生物瓣膜,但不知是否可作为骨再生引导膜?目的:观察聚羟基丁酸/羟基戊酸共聚酯膜的生物相容性,并评价其成骨能力。方法:采用MTT法检测100%,75%,50%,25%聚羟基丁酸/羟基戊酸共聚酯材料浸提液对犬骨髓间充质干细胞相对增殖度的影响,并评价其细胞毒性;在犬胫骨缺损模型左右两侧远心端骨缺损上方覆盖聚羟基丁酸/羟基戊酸共聚酯膜作为实验组,在近心端仅以骨膜瓣复位作为对照组。结果与结论:100%,75%,50%,25%聚羟基丁酸/羟基戊酸共聚酯膜的细胞毒性分级为0～1级,对骨髓间充质干细胞的生长及增殖无毒性;实验组术后第2周即可见新骨形成,12周时骨缺损区已完全被新骨充填,骨修复质量明显优于对照组。表明聚羟基丁酸/羟基戊酸共聚酯膜具有良好的生物相容性,对骨髓间充质干细胞无明显毒性,引导成骨能力强。     

红细胞膜蛋白异常与膜骨架相关溶血性贫血的发生

红细胞膜为双层磷脂结构,其间镶嵌着多种膜蛋白。这些膜蛋白包括包埋在脂质双分子层中的整合蛋白及存在于膜内侧的细胞膜骨架蛋白,而后者与红细胞膜缺陷所致的     

Ultrasound-induced cell membrane porosity

Recent studies of ultrasound (US) methods for targeted drug delivery and nonviral gene transfection revealed new, advantageous possibilities. These studies utilized US contrast agents, commonly stabilized microbubbles, to facilitate delivery and suggested that US delivery resulted from cell sonoporation, the formation of temporary pores in the cell membrane induced by US. Using voltage clamp techniques, we obtained real-time measurements of sonoporation of single Xenopus oocyte in the presence of Optison trade mark, an agent consisting of albumin-shelled C(3)F(8) gas bubbles (mean diameter 3.2 microm). Ultrasound increased the transmembrane current as a direct result of decreased membrane resistance due to pore formation. We observed a distinct delay of sonoporation following US activation and characteristic stepwise increases of transmembrane current throughout US duration. We discovered that the resealing of cell membrane following US exposure required Ca(2+) entering the cell through US-induced pores.     

血液透析膜的生物相容性

通过比较不同种血液透析膜的材料学特点,探讨了血液透析膜相容性的基本条件,将血液透析膜分为纤维素膜和合成膜两种类型,阐述了血液透析膜生物相容性的研究现状。目前各种新型的膜材料在不断地研发,部分已在临床使用或即将问世,如维生素E修饰的透析膜、多黏菌素B修饰的透析膜、甲壳素膜、以及人肾单位透析器和生物活性膜等。研制高通量、高效、生物相容性好的透析膜仍将是今后发展的主要方向。随着高分子材料和纳米技术的不断发展,透析膜的透析效果、生物相容性将逐步提高。