大鼠局灶性脑缺血模型及其与C反应蛋白变化的关系

目的 改进大鼠大脑中动脉梗塞法,建立更接近于临床缺血性脑卒中及其再扩灌注的可靠模型,并观察其与血甭Ｃ反应蛋白变化的。方法沿大鼠右颈内动脉插入长２．１￣２．３ｃｍ直径０．２０５ｍｍ的单股尼龙丝,直达大脑中动脉起始部开口,阻断其血流,观察大鼠神经病学改变及脑组织形态学变化,并测定血清Ｃ反应蛋白含量。结果 术后大鼠表现特殊体态及典型追尾征,６ｈ大脑中动脉供血区出现缺血性外观（ＴＴＣ染色）及相应组织学变化     

超声照射对声振微泡稳定性的影响

目的与方法造影剂微泡浓度、大小是影响心肌声学显影最重要因素。本研究采用２×２×４析因分析法分析不同超声照射条件对造影剂微泡浓度及直径的影响,即声波频率、能量以及照射时间对微泡浓度、大小的单独及交互作用。为临床行静脉心肌声学造影检查时选择适宜的超声照射条件提供参考。结果能量越大、照射时间越长,微泡破坏越多,平均直径越小：照射频率对微泡浓度影响不大,但影响微泡大小,频率越高,微泡越小。结论为减少超声照射对微泡的破坏,提高心肌声学造影效果,应尽可能选用低能量、低频率超声波,并减少不必要的照射时间。     

Optimizing contrast-enhanced abdominal CT in infants and children using bolus tracking

OBJECTIVE: Manual administration of IV contrast material results in unpredictable injection rates. Our purpose was to determine the effect of bolus tracking on overall abdominal helical CT scan quality, particularly on hepatic enhancement, in children with manually administered contrast media. MATERIALS AND METHODS: We compared 33 abdominal helical CT scans of 29 children in whom bolus tracking was used with 22 CT scans of a control group of 21 children in whom bolus tracking was not used. All contrast material was administered by manual injection. Qualitative assessment was made of organ and vessel enhancement and overall scan appearance. Quantitative assessment using region-of-interest cursors was performed at three anatomic levels, and the results for the two groups of children were compared. RESULTS: Qualitative comparison of enhancement parameters between the bolus tracking group (number given first) and the control group (number given second) yielded the following: splenic artifact in 9% versus 23% (p = .24); inferior vena cava flow artifact in 3% versus 27% (p = .01); scanning during the nephrographic phase in 89% versus 59% (p = .02); and good quality grade in 79% versus 64% (p = .23). Significantly greater hepatic enhancement (as measured in mean Hounsfield units) was achieved in the bolus tracking group than in the control group at the superior (48.5 versus 28.6; p < .001), middle (47.9 versus 32.3; p < .001), and inferior (48.2 versus 36.5; p = .01) levels. Hepatic enhancement increased significantly from the superior to the inferior level in the control group (p < .02), whereas enhancement was homogeneous in the bolus tracking group (p > .50). CONCLUSION: Bolus tracking provides improved contrast enhancement, including significantly greater hepatic enhancement, during abdominal helical CT in children in whom the rate of injection of contrast material is unpredictable.     

Polymorphisms at - 174 and in the 3' flanking region of interleukin-6 (IL-6) gene in patients with myasthenia gravis

We examined the bi-allelic polymorphism at - 174 in the promoter region and the polymorphism in the 3' flanking AT rich region of the interleukin-6 (IL-6) gene in Swedish patients with myasthenia gravis (MG) and ethnically matched healthy individuals. There was no association between the polymorphisms and the disease. There was no relation of the polymorphisms to the clinical variables, the thymic histopathologies, the level of serum acetylcholine receptor antibodies or the concentrations of IgG and its subclasses. Our data yield no evidence for the IL-6 gene contributing to the disease susceptibility.     

Opioid peptide receptor studies, 11: involvement of Tyr148, Trp318 and His319 of the rat mu-opioid receptor in binding of mu-selective ligands

Previous data obtained with the cloned rat mu opioid receptor demonstrated that the "super-potent" opiates, ohmefentanyl (RTI-4614-4) and its four enantiomers, differ in binding affinity, potency, efficacy, and intrinsic efficacy. Molecular modeling (Tang et al., 1996) of fentanyl derivatives binding to the mu receptor suggests that Asp147, Tyr148, Trp318, and His319 are important residues for binding. According to this model, Asp147 interacts with the positively charged opiate agonist to form potent electrostatic and hydrogen-bonding interactions. In this study, the role of weak electrostatic and hydrogen-bonding "pi-pi" interactions of the O atom of the carbonyl group and the phenyl ring structures of RTI-4614-4 and its four enantiomers with residues Tyr148, Trp318, and His319 were explored via site-directed mutagenesis. Tyr148 (in transmembrane helix 3 {TMH3}), Trp318 (TMH7), and His319 (TMH7) were individually replaced with phenylalanine or alanine. Receptors transiently expressed in COS-7 cells were labeled with [125I]IOXY according to published procedures. Mutation of Tyr148 to phenylalanine reduced the binding affinities of some mu-selective agonists (2-7 fold) but did not alter the affinities of DAMGO, naloxone, and the non-selective opiates etorphine and buprenorphine. In contrast, this mutation significantly increased the binding affinities (decreased the Kd values) of [D-Ala2,D-Leu5]enkephalin, IOXY, and dermorphin. Mutation of Trp318 decreased opioid receptor binding to almost undetectable levels. Substitution of alanine for His319 significantly reduced binding affinities for the opioid ligands tested (1.3- to 48-fold), but did not alter the affinities of naloxone and bremazocine. These results indicate the importance of Tyrl48 and His319 for the binding of fentanyl derivatives to the mu receptor. Functional studies using the mutant receptors will provide additional insight into the mechanism of action of RTI-4614-4 and its four enantiomers.     

肉毒碱治疗TPN大鼠肝脂肪变性的研究

目的 探讨在全胃肠外营养（ＴＰＮ）中补充肉毒碱减轻肝脂肪变性的作用。方法 １８只正常Ｗｉｓｔａｒ大鼠和１９只肝硬化Ｗｉｓｔａｒ大鼠分别随机分为６组,Ａ１组、Ａ２组,自由进食和进水（各６只）;Ｂ１组、Ｂ２组,ＴＰＮ（分别６只、７只）;Ｃ１组、 ,ＴＰＮ加肉毒碱（各６只）。各组实验结束后测肝功能,肝脂肪及行肝脏的组织学检查。结果 ＴＰＮ组肝内脂肪显著２,ＴＰＮ＋肉毒碱组肝内脂肪明显减少。结论 在ＴＰＮ     

急性非淋巴细胞白血病中MGMT与p53基因突变的研究

目的 探讨肿瘤抑制基因ｐ５３、ＭＧＭＴ在急性非淋巴细胞白血病（ＡＮＬＬ）中的改变。方法 用聚合酶链反应－单链构象多态性（ＰＣＲ－ＳＳＣＰ）技术对３１例ＡＮＬＬ患者、２２例正常人ｐ５３基因第５、６、７、８外显子和ＭＧＭＴ基因第１、４外显子进行突变分析。结果 ３１例ＡＮＬＬ中５例存在ｐ５３基因突变、４例存在ＭＧＭＴ基因突变,其中２例ｐ５３与ＭＧＭＴ同时发生突变。结论 ｐ５３基因突变在白血病发生中起一定     

基于小波变换的甲襞微循环图像边缘检测

讨论了小波变换在图像边缘检测、分类与描述中的作用,并根据甲襞微循环图像的特点,利用三次样条二进小波,采用Ｍａｌａｔ快速算法进行小波分解,成功地提取了甲襞微循环图像的边缘。