聚乳酸骨固定材料的研究

用聚乙烯醇(PVA)的二甲基亚砜(DMSO)溶液对水热反应法合成的超细羟基磷灰石(HAP)进行表面改性，用溶液分散复合法分别制备了HAP含量均为0．03g／mE的聚乳酸(PLLA)／HAP和PLIA／HAP-PVA复合物，并经过挤出成型得到φ=5mm的棒材。重点研究了热拉伸取向的拉伸规律及表面改性前后HAP粒子在PLLA基质中的分散情况。结果表明，经PVA改性的HAP粒子在PLLA基质中的分散要明显优于未经改性的HAP粒子。拉伸取向后PLLA／HAP-PVA复合材料的弯曲强度达262MPa。     

耒阳市1093例不同年龄人群缺锌状况的调查分析

[目的]探讨人体内锌缺乏与年龄是否相关。[方法]采集头发用强酸消化后，利用北京振教科贸有限公司产WL-3微量元素分析仪进行检测。[结果]我们发现儿童的缺锌率高于青少年和成人人群，具有显著的统计学意义（P〈0．05），其中3～5岁时的儿童的缺锌率达到了79．1％。而青少年与成人之间的缺锌率并无差异（P〉0．05），分别为20．5％和18．4％。[结论]因膳食结构不当引起锌缺乏在儿童中常见，由此我们应当根据不同年龄阶段特点进行不同的补锌措施。     

Improved anchorage in osteoporotic vertebrae with new implant designs.

The goal of our study was to evaluate two newly developed implant designs and their behavior in terms of subsidence in lumbar vertebral bodies under cyclic loading. The new implants were evaluated in two different configurations (two small prototypes vs. one large prototype with similar load-bearing area) in comparison to a conventional screw-based implant (MACS TL). A pool of 13 spines with a total of 65 vertebrae was used to establish five testing groups of similar bone mineral density (BMD) distribution with eight lumbar vertebrae each. In additional to BMD assessment via dual-energy X-ray absorptiometry, cancellous BMD and structural parameters were determined using a new generation in vivo 3D-pQCT. The specimens were loaded sinusoidally in force control at 1 Hz for 1000 cycles at three load levels (100, 200, and 400 N). A survival analysis using the number of cycles until failure (Cox regression with covariates) was applied to reveal differences between implant groups. All new prototype configurations except the large cylinder survived significantly longer than the control group. The number of cycles until failure was significantly correlated with the structural parameter Tb.Sp. and similarly with the cancellous BMD for three of five implants. In both large prototypes the cycle number until failure significantly correlated with the preoperative distance to the upper endplates. Although the direct relationship between bone structure or density and mechanical breakage behavior cannot be conclusively proven, all the prototypes adapted for poor bone structure performed better than the comparable conventional implant.     

Application of an immunosensor for the detection of the β-lactam antibiotic, cephalexin

Public concern surrounding antibiotic contamination in food and food products has made it imperative to develop analytical methods for their detection. Polyclonal antibodies were used in the development of a surface plasmon resonance (SPR)-based inhibition immunoassay for cephalexin. A conjugate consisting of cephalexin-bovine serum albumin (BSA) was immobilized on the dextran gel surface of the sensor chip. Binding/regeneration studies of antibody to immobilized cephalexin were studied and dissociation of the antibody from the immobilized cephalexin was easily achieved with 10 mmol l^-1 NaOH. Forty surface regeneration cycles were carried out and found to be reproducible with only a 7.4% decrease in binding over this number of regenerations. Model inhibition immunoassays for cephalexin were developed in PBS and spiked milk samples with detection ranges of 4.88 to 2,500 ng ml^-1 and 244 to 3,906 pg ml^-1, respectively.     

应用电泳技术分析飞行员富含三酰甘油脂蛋白亚组分及其代谢特征

目的 分析富含三酰甘油脂蛋白(TRLs)分子组成及其代谢特征.方法应用脂蛋白电泳技术,对30例飞行员空腹和脂肪负荷餐后血浆做脂蛋白分析,以扫描图面积表示各亚组分构成,观察脂蛋白亚组分变化特点.结果 30例飞行员TRLs清除延迟发生率46.67%.TRLs分子脂蛋白亚组分由极低密度脂蛋白(VLDL)、中密度脂蛋白(IDL)、低密度脂蛋白(LDL)、乳糜微粒(CM)和脂蛋白a[LP(a)]组成.TRLs清除延迟典型扫描图特征为LDL左侧区面积增高,呈双峰或多峰.LDL、VLDL区面积增高,伴有高密度脂蛋白(HDL)面积降低.结论 高三酰甘油血症致动脉粥样硬化作用是在代谢水平异常所致的TRLs清除延迟,TRLs清除延迟是核心环节.     

体表电位标测微机系统(Ⅰ型)

本系统的107个电极中,103个分布于胸、背部,1个为参考电极,1个为V_3,其余用于肢导。本系统除能绘出2、4、8ms任意间隔的103通道同步的体表等电位图,常规12导联和V_(7 9)心电图,胸、背部位的心电图外,还可记录R峰值等电位图,∑R,Q波等电位图,nQ30、40,极大、极小轨迹图等。     

Crystal structure and conformation of polypeptides: L-leucylglycylglycylglycine

Crystals of L-leucylglycylglycylglycine, LGGG (C₁₂H₂₂N₄O₅), grown from an ethanol-water solution, are orthorhombic, space groups P2₁2₁2₁, with unit cell dimensions (at 22 ± 3°) a = 9.337(1), b = 10.995(1), c = 15.235(1)Å, v = 1563.4 ų, Z = 4 with a density of D_obs= 1.29 g-cm^-3 and D_calc= 1.279 g°cm^-3. The crystal structure was solved by the application of direct methods and refined to an R value of 0.029 for 1018 reflections with I ± 2s?. The molecule exists as a zwitterion in the crystal. The trans peptide backbone takes up a folded conformation at the middle glycylglycyl link accompanied by a significant nonplanarity up to Δω of 8° at the middle peptide and is relatively more extended at the two ends. The molecules are linked together intermolecularly in an infinite sequence of head to tail 1–4′ hydrogen bonds, as is typical of charged peptides. It is interesting to note that while glycylglycylglycine takes up an extended β-sheet conformation, addition of Leu to the N-terminal results in a bent conformation.     

Membrane flow within the myelin sheath in IDPN neuropathy

This report describes some aspects of beta,beta'-iminodipropionitrile (IDPN) neuropathy in rats as observed by ultrastructural methods and X-ray diffraction. Light microscopy shows gross swelling of the axons in proximal lumbar spinal roots 8 days after intraperitoneal injection of IDPN. Mean axon cross-sectional area and mean axon perimeter increased to 280% and 160% of their control values, respectively. At the same time, myelin membrane packing was not visibly disturbed. In addition, X-ray diffraction patterns, recorded under physiological conditions, demonstrate that the myelin lipid bilayer thickness and widths of the aqueous spaces between bilayers did not change. Related observations are made on posterior tibial nerve (PNS myelin) and ventral spinal cord (CNS myelin). The various observations together are interpreted in terms of a fluid myelin membrane. It is proposed that the myelin membrane flows during axon swelling even though normal membrane-membrane contacts are maintained within the sheath. Membrane flow and slippage between membranes are explained in terms of a molecular model of the myelin multilayer.     

人抗HBsAg噬菌体抗体Fab段基因的序列分析及表达

对已建的噬菌体抗体库分离出来的人抗－ＨＢｓ克隆进行了序列分析和表达研究，发现４个克隆中３个克隆的重链和轻链完全相同，ＤＮＡ序列分析表明ＶＨ分别属于ＶＨ１亚群和Ⅱ亚群，其轻链ＶＬ分别属于ＶλⅡ亚群和ＶλⅠ亚群。构建了可溶性Ｆａｂ段表达载体，显示出在细菌中表达的Ｆａｂ段抗体与ＨＢｓＡｇ特异性结合，这说明所筛选出来的噬菌体抗体具有ＨＢdisplay status