浅谈钛及其合金的应用

目前世界各国对钛产业的投资热情逐步高涨,我国的钛工业也得到了空前的发展,钛及其合金已应用于生活的各个领域。钛及其合金的应用主要取决于它们的特点以及对产品的要求。现将钛及其合金的基本性质以及主要用途作一简单介绍,以期引起更多人的关注,从而对钛工业的发展起到推动作用。     

常规超声定量评估骨龄

目的 与X线评估骨化率（OR）对比,评价常规超声评估标准骨龄（BA）的价值及其简易方法。方法 对215例患者（男88例,女127例）于1周内先后行左手及腕部X线检查和超声检查,测量桡骨、尺骨,第1、3、5掌骨,第1、3、5近节指骨,第3、5中节指骨及第1、3、5远节指骨共13块骨骼的骨化中心及骨骺长径,计算各目标骨骨化中心与骨骺长径之比,获得其OR及BA,分析OR与BA的相关性。结果 男、女性患者各目标骨的OR与BA呈中-高度相关（r_男为0.77~0.94,r_女为0.77~0.93,P均<0.001）,13块骨骼的OR总和与BA呈高度相关（r_男=0.96,r_女=0.96,P均<0.001）,桡骨、尺骨OR总和与BA呈高度相关（r_男=0.95,r_女=0.95,P均<0.001）。结论 常规超声具有定量评估BA的潜在价值;仅测量桡骨及尺骨或可作为超声评估BA的简易方法。     

Gene Transfection Mediated by Ultrasound and Pluronic P85 in HepG2 Cells

In order to assess whether gene transfection could be mediated by ultrasound in associa- tion with P85 and find the appropriate parameters of ultrasound irradiation, the effects of ultrasound with or without P85 on gene transfection of HepG2 cells were examined. The HepG2 cells were irra- diated by ultrasound at 1 MHz, 0.4-2.0 W/cm2 and 50% duty cycle with plasmid encoding enhanced green fluorescent protein (EGFP) as a report gene. Forty-eight h later, the expression of EGFP was detected under the fluorescence microscopy. Transfection efficacy was quantitatively assessed by flow cytometry, and cell viability was evaluated by trypan blue exclusion. The results showed that the transfection efficacy was increased with the increases in ultrasound output power and the ideal trans- fection efficacy was achieved in HepG2 cells irradiated by ultrasound at 0.8 W/cm2 for 30 s. The transfection efficacy in ulstrasound P85 group was three times higher than in single ultrasound group [(17.63±1.07)% vs (5.57±0.56)%, P<0.05]. The cell viability was about 81% and 62% in ultrasound group and ultrasound P85 group respectively. It was concluded that ultrasound in combination with P85 could mediate the gene transfection of HepG2 cells, ideal transfection efficacy was achieved by ultrasound irradiation at 0.8 W/cm2 for 30 s, and P85 could somewhat increase the damage to cells caused by ultrasound.     

Ultrasound and Microbubbles： Their Functions in Gene Transfer In Vitro

To examine the role of ultrasound in gene delivery in vitro, three cells lines were exposed to the low-frequency ultrasound of varying intensities and for different durations to evaluate their effect on gene transfection and cell viability of the cells. Microbubble （MB）, Optison （10%）, was also used to observe the role of the microbubbles in gene transfection. The results demonstrated that as the ultrasound intensity and the exposure time increased, the gene transfer rate increased and the cell viability decreased, but at high energy intensities, the cell viability decreased dramatically, which caused the transfer rate to decrease. The most efficient ultrasound intensity for inducing gene transfer was 1 W/cm^2 with duration being 20 s. At the same energy intensity, higher ultrasound intensity could achieve maximal gene transfer rate earlier. Microbubbles could increase ultrasound-induced cell gene transfer rate by about 2 to 3 times mainly at lower energy intensities. Moreover, microbubbles could raise the maximum gene transfer rate mediated by ultrasound. It is concluded that the low-frequency ultrasound can induce cell gene transfer and the cell gene transfer rate and viability are correlated with not only the ultrasound energy intensity but also the ultrasound intensity, the higher ultrasound intensity achieves its maximal transfer rate more quickly and the ultrasound intensity that can induce optimal gene transfer is 1 W/cm^2 with duration being 20 s, and microbubbles can significantly increase the maximal gene transfer rate in vitro.     

几种共聚物对小鼠骨骼肌超声介导基因转染表达的影响

目的 探讨超声和共聚物在质粒DNA对小鼠骨骼肌基因转染中的影响.方法 应用三种水溶性不同的共聚物F127,L61和P85,与DNA混合后直接小鼠胫前肌注射,并超声辐照.超声频率为1 MHz,脉冲重复频率100 Hz,占空系数为20%,用3 W/cm2声强辐照1 min.实验1周后取出胫前肌并快速冰冻切片,荧光显微镜计数表达GFP的转染肌纤维数,苏木精和伊红染色评价肌肉损伤情况.结果 三种共聚物均可显著提高质粒DNA的基因转染(P＜0.01),P85的基因转染效率高于其他两种共聚物(P＜0.05).超声虽对单纯质粒、F127和L61组的基因转染无显著促进作用,但与P85有协同作用,可显著提高P85组的基因转染效率(P＜0.01).在给定超声剂量和共聚物浓度下,二者在提高质粒DNA基因转染的同时,并不显著增加对组织的损伤作用.结论 共聚物P85不但可显著提高质粒DNA在小鼠骨骼肌的基因转染,且与超声具有协同作用.     

超声技术在肾癌合并下腔静脉癌栓诊断中的应用

目的:探讨常规超声、彩色多普勒超声、超声造影及术中超声在肾癌合并下腔静脉癌栓的诊断及临床分型中的应用价值。方法:对7例肾癌合并下腔静脉癌栓的患者进行常规超声、彩色多普勒超声检查,其中3例行超声造影检查,3例行术中超声检查。所有病例均经手术及病理证实。结果:所有下腔静脉栓子均为癌栓,癌栓分型为Ⅱ型4例,Ⅲ型2例,Ⅳ型1例。结论:超声技术对肾癌合并下腔静脉癌栓的诊断与鉴别诊断具有重要价值,并且能够脉对癌栓进行准确分型,对临床手术治疗及预后判断具有指导性意义。     

在不同细胞系中共聚物对超声介导基因转染的影响

目的 探讨超声和共聚物在不同细胞系中对基因转染的协同作用.方法 应用三种水溶性不同的共聚物F127,L61和P85;超声频率为1 MHz,脉冲重复频率100 Hz,占空系数为20%,用1 w/cm2声强照射20 s.选用C2C12,3T3-MDEI,CHO和H2K四种细胞系为研究对象.质粒DNA为可产生绿色荧光蛋白的GFP.应用荧光显微镜和流式细胞仪评价转染率,台盼蓝染色评价细胞的成活率.结果 超声可介导所有四种细胞系的基因转染.在C2C12,3T3-MDEI和CHO细胞系,共聚物可显著促进超声介导的基因转染效率(P＜0.01),对H2K细胞系共聚物不但不能促进超声介导的基因转染、,其中疏水性共聚物P85和L61反而使超声介导的基因转染效率降低(P＜0.05).结论 共聚物对不同细胞系超声介导的基因转染效率产生不同的影响,这种差异可能与细胞膜蛋白缺陷有关.     

幽门螺杆菌黏附素研究进展

幽门螺杆菌(Helicobacter pylori,Hp)是一种定植于胃和十二指肠黏膜的革兰阴性菌,与慢性胃炎、消化道溃疡和胃癌的发生密切相关.Hp感染率在世界人群中超过50％.目前针对Hp的感染主要是采取三联或四联抗菌疗法.然而,随着耐药菌株的不断增多,研制安全有效的疫苗成为控制Hp感染的新出路.Hp感染和致病涉及多个环节,其中Hp黏附定植于胃和十二指肠道黏膜表面是首要条件.决定Hp定居的因素包括细菌鞭毛动力,尿素酶和黏附素.黏附素作为Hp定植的物质基础,在幽门螺杆菌基因重组疫苗的研究中受到越来越多的关注.     

颈椎后前向松动术和牵引后颈椎后前向松动术对椎动脉血流量的影响

目的研究单纯的后前向松动（单纯松动术）和持续牵引的同时行后前向关节松动（牵引松动术）对椎动脉血流量的影响。 方法选取健康受试者30例。所有受试者均接受单纯松动术和牵引松动术干预,2种干预方案的顺序随机,每种干预间歇2d。于每次干预前、后采用彩色超声多普勒诊断仪采集椎动脉的血流动力学参数。 结果单纯松动术干预后,受试者的收缩峰值血流速度［（46.32±4.98）cm/s］、舒张末期血流速度［（17.47±3.39）cm/s］、平均血流速度［（27.12±9.01）cm/s］、阻力指数［（0.70±0.06）］分别与治疗前比较,差异无统计学意义（P>0.05）。牵引松动术干预后,受试者的收缩峰值血流速度［（45.98±5.10）cm/s］、舒张末期血流速度［（18.01±4.27）cm/s］、平均血流速度［（26.09±6.89）cm/s］、阻力指数［（0.70±0.09）］分别与治疗前比较,差异均无统计学意义（P>0.05）。 结论颈椎后前向松动和牵引松动产生的椎间运动对椎动脉血流量无影响。     

超声造影对肝脏小占位病变的诊断价值

目的分析较小肝脏占位性病变（直径≤3cm）超声造影表现,探讨超声造影对肝脏小占位病变的诊断价值。方法回顾性分析136例患者156个直径≤3cm的肝脏占位性病变常规超声及超声造影表现,其中恶性病灶74个,良性病灶82个。利用TIC软件分析除外术后瘢痕、坏死结节及性质待定的病灶外的142个病灶造影剂灌注模式,并与病理结果进行对照研究。结果74个恶性病灶及除坏死结节、术后瘢痕外的72个良性病灶不同程度增强。动脉相原发性肝细胞癌（HCC）100%（49/49）增强,其中71.43%（35/49）呈整体增强;实质相85.71%（42/49）呈典型的＂黑洞＂征。转移性肝癌动脉相特征性地表现为厚环状增强者占52.00%（13/25）;实质相88.00%（22/25）呈＂黑洞＂征。良性病变中动脉相后期呈整体增强、斑片状增强及环状增强者分别为48.61%（35/72）、18.06%（13/72）、33.33%（24/72）;实质相呈＂黑洞＂征、强度低于、近似于周围肝组织者分别为1.39%、30.56%、68.06%。肝血管平滑肌脂肪瘤和炎性假瘤造影呈快进快退,类似于恶性肿瘤。TIC分析良性病灶始增时间、增强时间及达峰时间均晚于恶性病灶,差异具有显著性,峰值强度在两组之间无显著性差异。HCC和转移性HCC上述参数无差异。血管平滑肌脂肪和炎性假瘤TIC上述各参数低于良性组其余病变。结论超声造影对提高肝脏小占位病变的定性诊断率有重要的价值,部分良性病变造影表现缺乏特异性,确诊仍须结合其他影像学方法或穿刺活检。