Development of sutureless vascular connecting system for easy implantation of small-caliber artificial grafts

A novel sutureless vascular connecting system, an assembly with a delivery rod, an introducing sheath, and a connecting device, was developed for easy implantation of small-caliber vascular grafts less than 2 mm in internal diameter. A microporous stainless tube (length 2 mm, external diameter 1.6 mm, wall thickness 65 µm, pore diameter 400 µm, pore-to-pore distance 500 µm) was designed to serve as a connecting device. The feasibility of the system was tested using two types of preliminary animal experiments. One animal model consisted of graft implantation into the rat abdominal aorta (1.5 mm in diameter). The connecting device was inserted into the proximal and distal ends of the aorta through the introducing sheath by pushing the delivery rod with the connecting device placed over it. Subsequently, the aortic segments were inserted into both ends of model grafts made of segmented polyurethane (1.8 mm in internal diameter) and were fixed with banding silk threads from the exterior. The procedure was completed within 20 min without requiring specialized microsurgery techniques. Blood leakage and obstruction did not occur. The second model consisted of an end-to-end anastomosis between rabbit common carotid arteries (2 mm in diameter), which was performed within several minutes of blood flow interruption. Scanning electron microscopy demonstrated that the luminal surface of the device was fully covered with endothelial cells (ECs) after 1 week as a result of transluminal ingrowth of native ECs through the micropores in the device. This endothelialization may prevent early thrombus-induced occlusion. This simple and “easy-to-learn” technique will promote the development of small-caliber arterial grafts, and furthermore, it may have potential for clinical application.     

Meta-analysis of gross insertions causing human genetic disease: novel mutational mechanisms and the role of replication slippage

Although gross insertions (>20 bp) comprise <1% of disease-causing mutations, they nevertheless represent an important category of pathological lesion. In an attempt to study these insertions in a systematic way, 158 gross insertions ranging in size between 21 bp and approximately 10 kb were identified using the Human Gene Mutation Database (www.hgmd.org). A careful meta-analytical study revealed extensive diversity in terms of the nature of the inserted DNA sequence and has provided new insights into the underlying mutational mechanisms. Some 70% of gross insertions were found to represent sequence duplications of different types (tandem, partial tandem, or complex). Although most of the tandem duplications were explicable by simple replication slippage, the three complex duplications appear to result from multiple slippage events. Some 11% of gross insertions were attributable to nonpolyglutamine repeat expansions (including octapeptide repeat expansions in the prion protein gene [PRNP] and polyalanine tract expansions) and evidence is presented to support the contention that these mutations are also caused by replication slippage rather than by unequal crossing over. Some 17% of gross insertions, all >or=276 bp in length, were found to be due to LINE-1 (L1) retrotransposition involving different types of element (L1 trans-driven Alu, L1 direct, and L1 trans-driven SVA). A second example of pathological mitochondrial-nuclear sequence transfer was identified in the USH1C gene but appears to arise via a novel mechanism, trans-replication slippage. Finally, evidence for another novel mechanism of human genetic disease, involving the possible capture of DNA oligonucleotides, is presented in the context of a 26-bp insertion into the ERCC6 gene.     

A persistent T cell expansion in the peripheral blood of a normal adult male: a new clinical entity?

A dramatic and persistent T cell expansion in a healthy adult male was initially identified, using anti-T cell receptor for antigen (TCR)-specific MoAbs. The expanded T cells were found to be expressing TCR containing V alpha 12.1 and V beta 5.2, and they composed approximately one third of all the CD8+ T cells. The cells were shown to be not only non-activated (HLA-DR-, IL-2R-) but also of 'virgin' cell type (CD45RA+/CD45RO-) and they persisted over the observation period of more than one and a half years. Various T and B cell markers, and all other laboratory and physical parameters analysed, were normal. The expanded CD8+ T cells were further characterized by polymerase chain reaction (PCR) amplification, using V beta- and C beta-specific primers, followed by hybridization with J beta-specific probes. Close to 90% of the V alpha 12.1+ V beta 5.2+ T cells were found to utilize the J beta 2.5 gene segment, thus strongly suggesting the expanded T cells to be monoclonal. The condition may constitute a T cell counterpart to 'monoclonal gammopathy of undetermined significance' (MGUS), and by analogy we suggest it should be designated 'monoclonal T cell expansion of undetermined significance' (MTUS).     

血管内皮祖细胞的体外扩增特性研究

目的:探讨血管内皮祖细胞(EPCs)在体外扩增特性。方法:利用磁性活化细胞分选系统(MACS)系统富集CD34⁺细胞,在相同条件下与同批的单个核细胞(MNC)、CD34⁺和CD34^-混和细胞进行对照培养,比较EPCs体外扩增效果。另外研究血管内皮生长因子(VEGF)和传代培养对细胞分化、扩增动力学和细胞凋亡的影响。应用细胞免疫化学和流式细胞术对细胞定性定量分析。结果:MNC培养、CD34⁺和CD34^-细胞混和培养明显高于CD34⁺细胞单独培养EPCs扩增率(P＜0.05),一旦细胞形成线索样结构行传代培养明显低于未传代的细胞凋亡(P＜0.05)。VEGF对细胞凋亡(P＞0.05)无明显影响,这些分化的EPCs免疫细胞化学染色CD34、vWF、KDR、CD31阳性,并且吞噬乙酰化低密度脂蛋白(Ac-LDL)。培养7d流式细胞检查CD34⁺、AC133^＋分别占贴壁(AT)细胞的68.2%±6.3%(n=6)、57.2%±9.8%(n=6)。结论:MNC培养、CD34⁺和CD34^-细胞混和培养提高了EPCs扩增率,早传代使凋亡率明显降低。VEGF对EPCs体外扩增无明显影响。     

皮肤扩张术修复头皮合并颅骨缺损

目的探讨头皮合并颅骨缺损的修复方法。方法对2000年至2007年治疗的6例头皮合并颅骨缺损患者，采用皮肤扩张术修复头皮，钛网修补颅骨缺损。结果6例患者中，1例患者出现皮瓣下积液，经抽吸、加压包扎后愈合；其余病例未出现感染、血肿及皮瓣坏死等并发症，外观满意。结论皮肤扩张术和钛网联合应用是修复头皮合并颅骨缺损的较好方法。     

环孢菌素A抑制小鼠同种心脏移植急性排斥反应中Lymphotactin表达的研究

目的：研究小鼠同种心脏移植急性排斥反应中淋巴细胞趋化因子（lptn）的表达情况及环孢菌素A（cyclosporine A, CsA）的抑制作用。 方法： 改良Banff评分系统判断同种小鼠移植心急性排斥反应程度，RT-PCR检测移植心组织内淋巴细胞趋化因子表达水平，ELISA方法检测心脏移植小鼠脾细胞活化T细胞核因子(NFAT)活性。 结果： C57BL/6-Balb/c急性排斥组小鼠移植术3 d后脾脏显著增大。术后第5、7 d移植心肌间淋巴细胞浸润程度评分分别为2.667±0.577和2.333±0.577。C57BL/6-Balb/c+CsA组小鼠移植术后脾脏肿大明显减轻，术后第5、7 d心肌间淋巴细胞浸润程度评分分别为1.000±0.000和1.333±0.577。急性排斥组和CsA处理组小鼠移植心脏在术后第5 d和第7 d都可检测到Lptn mRNA阳性表达，但CsA处理组Lptn mRNA的表达明显弱于急性排斥组。治疗剂量的CsA可以完全抑制NFATc1活性。 结论： Lptn在早期移植免疫事件中具有重要的作用，CsA仅能部分抑制Lptn mRNA的表达。活化T细胞Lptn的表达调控存在NFAT以外的途径。     

Monitoring hemodialysis vascular access by digital phonoangiography

We are intrigued by the possibility of using digital spectral analysis to detect hemodialysis vascular access stenosis. Such a monitor could be inexpensive, noninvasive, and portable enough to allow continuous monitoring. This report suggests how individuals wishing to conduct such research can use a simple but effective transducer design we have employed, how the data so obtained can be analyzed in the time and frequency domains using inexpensive digital signal processing software available via the Internet, and how data recordings might be shared via the Internet to facilitate collaboration. © 2002 Biomedical Engineering Society. PAC2002: 8763Df, 8780Tq     

Grafts of dissociated cerebellar cells containing Purkinje cell precursors organize into zebrin I defined compartments

Summary A prominent feature of the mammalian cerebellum is its organization into parasagittal compartments. One marker of such compartments is the zebrin I molecule that is expressed by bands of Purkinje cells (PC). In order to understand better the basis for the development of this organization, we have transplanted dissociated rat cerebellar anlage, taken during the period of proliferation of PC precursors, into kainic acid lesioned adult rat cerebellum. As previously observed, the resultant grafts exhibited trilaminar structures reminiscent of the normal cerebellum. In every case, the PC in the resultant grafts were organized into zebrin I + and — compartments. In one case, most of the grafted PC were integrated into a region of PC deficient host molecular layer that was induced by pretreatment with kainic acid. Clear bands defined by zebrin I reactivity were seen where groups of the grafted PC had entered the host molecular layer. These bands did not correlate in distribution or size with host bands. Hypotheses compatible with these findings that involve specific and non-specific aggregation of PC are discussed.     

Determinants of pulmonary blood volume. Effects of acute changes in pulmonary vascular pressures and flow

To examine the effects of pulmonary vascular pressures and flow on pulmonary blood volume (PBV), experiments were performed at constant heart rate and zone 3 conditions (mean left atrial pressure (LAP) above airway pressure) in six anesthetized, open-chest dogs. PBV was calculated as the product of electromagnetic aortic flow and pulmonary mean transit time for ascorbate, obtained without blood withdrawal by polarographic recording of aortic ascorbate changes. In three series of experiments LAP was raised similarly in three steps, from 4.5 to 14.8 mmHg: by mitral constriction which reduced pulmonary blood flow, by blood volume expansion which more than doubled pulmonary blood flow, or by a combination of the two procedures which kept pulmonary blood flow constant. In all three series, LAP and mean pulmonary arterial pressure (PAP) rose in proportion, but PBV was better correlated to PAP (r=0.87±0.02) than to LAP (r=0.66±0.09). These experiments suggest that PAP is the most important factor in determining PBV under zone 3 conditions, whether PAP is raised by increasing pulmonary blood flow or by mitral constriction.     

人工组织神经移植物修复狗缺损坐骨神经后腓肠肌的形态观察

目的 了解复合型医用可降解材料制成的人工组织神经移植物辅加神经再生素修复狗坐骨神经缺损后，腓肠肌的形态变化。方法 将人工组织神经移植物连接在狗的坐骨神经缺损30mm处。以自体神经桥接和神经缺损的狗为对照组Ⅰ和Ⅱ。术后6个月时取腓肠肌进行称重、特殊染色和组织化学染色，显微镜下了解腓肠肌的形态变化并进行图像定量分析，同时了解肌纤维的超微结构变化。结果 术后6个月，实验组腓肠肌的萎缩形态指标变化均轻于对照组Ⅱ，而与对照组Ⅰ相似。结论 经人工组织神经移植物修复缺损的坐骨神经后，使腓肠肌又重新获得神经支配，肌肉萎缩明显减轻。