Pulse sequence optimization for MR imaging using a paramagnetic hepatobiliary contrast agent

Paramagnetic agents enhance contrast between tissues in magnetic resonance (MR) imaging by altering tissue relaxation times. The effect of these changes on MR image intensity depends in part on the choice of operator-controlled pulse sequence parameters. With the newly described paramagnetic hepatobiliary contrast agent, iron(III) ethylenebis-(2-hydroxyphenylglycine), Fe(EHPG)-, an in vivo experimental analysis of pulse sequence optimization was performed on the rat. We compared the enhancement of the liver divided by background noise, EL/N, of standard inversion-recovery (IR) and spin-echo (SE) T1-weighted pulse sequences and several pulse sequences theoretically predicted to have improved EL/N. Optimization of the echo time (TE = TEmin) gave a substantial (greater than 60%) increase in EL/N over the standard IR and SE pulse sequences. Images obtained with optimized repetition rate and inversion time gave only a slight additional improvement. Within the uncertainties of our relaxation measurements, the measured changes in EL/N with pulse sequence optimization corresponded well with theoretical predictions. With the experimental and theoretical data, the importance of using a short echo time to obtain maximal T1 contrast in contrast-enhanced MR imaging and the relative merits of optimized SE versus IR pulse sequences for contrast-enhanced MR imaging are discussed.     

双氯芬酸钠经皮电穿孔及电离子导入的研究

目的：考察离子导入和电穿孔对双氯芬酸钠经皮渗透的影响。方法：采用双室扩散池和SD大鼠皮、进行双氯芬酸钠饱和水溶液经皮被动扩散、离子导入（0．5mA/cm^2)和电穿孔导入（130V,740ms或100ms,200个脉冲,方波,占空比1：1）的 研究。结果：电穿孔和离子导入均能显著促进双氯芬酸钠的经皮渗透,其增渗倍数分别为25．1和7．5。延长脉冲7时间将改善电穿孔的促渗效果,初步研究表明本实验条件的电穿孔及离子导入未引起皮肤的损伤。结论：电穿孔技术可用于促进小分子解离型药物的经皮渗透。     

Aquaporin-4 autoantibodies in neuromyelitis optica spectrum disorders: comparison between tissue-based and cell-based indirect immunofluorescence assays

Background  

Neuromyelitis optica spectrum disorders (NMOSD) are severe central nervous system inflammatory demyelinating disorders (CNS IDD) characterized by monophasic or relapsing, longitudinally extensive transverse myelitis (LETM) and/or optic neuritis (ON). A significant proportion of NMOSD patients are seropositive for aquaporin-4 (AQP4) autoantibodies. We compared the AQP4 autoantibody detection rates of tissue-based indirect immunofluorescence assay (IIFA) and cell-based IIFA.     

[In Press] Posner-Schlossman syndrome induced LASIK keratectasia – a case report

Letter to the editor     

薄层扫描法测定梅花点舌丸中华蟾蜍毒基含量

目的：提供合适的方法,以控制梅花点舌丸的含量。方法：双波长薄层扫描法测定梅花点舌丸中华蟾蜍毒基的含量。λs=295nm,λn=370nm。在1。200－6．020μg范围内呈良好的线性（r=0.9978),同板和异板精密度试验的RSD值分别为0．092％主2．79％（n=5)。结果：平均加样回收率和RSD值分别为99．2％和1．14％（n=6),结论：本法简单、准确、可作为梅花点舌丸的质量控制方法。     

缺血性脑损伤诱导内源性神经干细胞的增殖和迁移

目的:观察缺血性脑损伤对内源性神经干细胞增殖、迁移的影响。方法:实验于2004-09/2005-03在新乡医学院人体解剖与组织胚胎重点实验室进行。10～12周体质量300～350g的健康雄性SD大鼠62只,由新乡医学院实验动物中心提供。按随机数字表方法将其分为正常组6只、假手术对照组14只、脑缺血再灌注组42只(分为再灌注1,3,5,7,10,15,20d7个时间点,每时间点6只)。参照Pulsinelli-Brierley法,夹闭大鼠双侧颈总动脉制作短暂性全脑缺血动物模型,全脑缺血10min后再灌注,假手术对照组不夹闭颈总动脉。于脑缺血再灌注不同时间点应用SABC免疫组化法染色显示5-溴-2-脱氧尿嘧啶阳性细胞和巢蛋白阳性细胞,光镜下观察并分析脑缺血损伤后内源性神经干细胞增殖、迁移的变化过程。结果:正常组、假手术对照组大鼠均存活,脑缺血再灌注组大鼠1d、5d、15d、20d各死亡1只,共58只大鼠进入结果分析。①正常组与假手术对照组室管膜下区、海马CA1区、齿状回区域均偶见5-溴-2-脱氧尿嘧啶阳性细胞和巢蛋白阳性细胞。②脑缺血再灌注后1d于海马、齿状回和室管膜下区均有5-溴-2-脱氧尿嘧啶阳性细胞和巢蛋白阳性细胞,随后逐渐增加,7～10d达高峰,术后20d仍有表达;在室管膜下区的5-溴-2-脱氧尿嘧啶阳性细胞和巢蛋白阳性细胞有向皮质、海马迁移的现象。结论:成年大鼠全脑缺血后7～10d内源性神经干细胞增殖达到高峰;增殖的内源性神经干细胞存在由增殖区向靶区迁移的现象。     

3－硝基－1，2，4－三唑类乏氧细胞放射增敏剂的构效关系

为了寻找毒性低、增敏作用强的乏氧细胞放射增敏剂，设计并合成了一系列５－溴－，５－甲基－，和５－未取代的３－硝基－１，２，４－三唑－１－乙酰胺类化合物，用ＨｅＬａＳ３细胞进行了体外试验。结果表明５－溴取代衍生物的增敏作用强于相应的５－甲基－或５－未取代的硝基三唑衍生物，但是它们的毒性亦增大。修饰１位乙酰胺侧链也可以改变化合物的增敏作用和亲脂性。在所测定的化合物中ＴＡ－１０１［２－（３－硝基－１－三唑基）乙酰胺］由于有高的增敏作用和低亲脂性，可能是一个有希望的放射增敏剂。