C端带Myc和多聚组氨酸双重标签基因的改构体J-HNP-1在COS-7细胞的转染表达

目的改构α-防御素-1(HNP-1)使其成为一端带J链的改构体J-HNP-1分子,并探索建立能有效表达和分泌J-HNP-1,其表达产物又易于被检测和分离纯化的哺乳动物细胞表达系统。方法利用重组PCR技术,使HNP-1一端带上J链;将J-HNP-1 DNA片段插入哺乳动物细胞表达载体pcDNA3.1(-)/Myc-HisC中,构建出C端带Myc和6×His的rpcDNA3.1(-)/Myc-HisC/J-HNP-1;将此重组真核表达载体导入COS-7细胞,分别从mRNA和蛋白质水平分析J-HNP-1的表达情况,并同步检测细胞可溶性蛋白及培养上清的抗菌活性。结果采用RT-PCR法从被转染的细胞中扩增出1条约786bp的片段,其大小与预测相符;采用Western印迹法,用抗His抗体检测到细胞可溶性蛋白及培养上清在相对分子质量约24×103处有强反应条带显示;细胞可溶性蛋白及培养上清的抗菌活性检测显示,经rpcDNA3.1(-)/Myc-HisC/J-HNP-1转染的COS-7细胞的可溶性蛋白和培养上清均有明显的抗菌活性。结论α-防御素-1(HNP-1)被成功改构成杀菌肽J-HNP-1;所建立的J-HNP-1哺乳动物细胞表达载体系统能有效表达和分泌活性J-HNP-1。     

实时三维超声对室间隔缺损的直视效果及影响因素分析

目的探讨实时三维超声（RT3DE）对室间隔缺损（VSD）全貌的直视效果及其影响因素。 方法应用RT3DE对238例VSD患者进行检查，其中包括法洛四联症（TOF）36例、完全型心内膜垫缺损（TECD）2例和十字交叉心2例。获取并切割“全容积三维”图像，寻找最佳视角显示病变结构全貌。 结果RT3DE对中型和大型VSD（直径≥5mm）的直视效果优于小型VSD（〈5mm）。可显示缺损的形状、部位及毗邻结构。胸骨旁四腔位和心底短轴位RT3DE图像效果最佳，胸骨旁长轴位及心尖五腔位次之。 结论VSD的大小、部位及三维图像质量是决定RT3DE观察效果的主要因素。RT3DE可清晰直视中型及大型VSD的全貌。     

Characterizing luminous efficiency functions for a simulated mesopic night driving task based on reaction time

The objective of this study is to test the luminous efficiency functions V(lambda), V'(lambda), V(10)(lambda) and their linear combinations on the basis of a data set gained from a simulated mesopic night-time driving experiment. Another aim is to provide 'real-world' data for the 'X framework' or 'linear combination model', and to find out its limits in a practical situation. Human performance was measured by the reaction time method. Results show that the single parameter of the linear combination of photopic and scotopic luminous efficiency functions can be determined analytically with little variation for a given mesopic background luminance level and a given visual target colour, but the computation leads to considerable deviations comparing all three target colours (red, green and blue) used in the experiment. The conclusion for the given experimental conditions is that the single parameter of the linear combination model has an increasing deviation for lower background luminance levels.     

腰椎穿刺术后头痛与卧床时间的关系

目的探讨腰椎穿刺术后平卧时间30min、2h对头痛的影响。方法对794例具有腰椎穿刺术适应证而无禁忌证并排除有关因素的患者，随机分为30min组、2h组。分别观察术后头痛发生率。结果30min组头痛发生率为（8／460）1．74％，2h组为（7／334）2.10％，两组组间比较均无显著性差异（P〉0．05）。结论本研究说明腰穿后卧床时间长短（30min～2h），对腰穿后头痛的发生率无影响，可缩短至30min，没有必要卧床2h，更没有必要卧床4～6h。     

Quantification of vitamin C in the rat brain in vivo using short echo-time 1H MRS.

Both ultrashort echo-time STEAM and MEGA-PRESS-edited spectroscopy were used to validate noninvasive quantification of vitamin C (ascorbate) in the developing rat brain, where changes in ascorbate concentration have been reported. Despite strong overlap with resonances from glutamine, glutamate, glutathione, and macromolecules, reliable quantification of ascorbate (Cramer-Rao lower bounds<0.2 micromol/g) by LCModel analysis of STEAM (TE=2 ms) spectra was possible at 9.4 T. Ascorbate concentrations quantified from the STEAM spectra were in very good agreement with concentrations calculated from fully resolved ascorbate resonances in MEGA-PRESS-edited spectra measured from identical volumes of interest. Ascorbate concentrations measured using STEAM decreased with increasing postnatal rat age, in agreement with published brain ascorbate concentrations measured in vitro using high-performance liquid chromatography (HPLC).     

Analysis of the strain relatedness of oral Candida albicans in patients with diabetes mellitus using polymerase chain reaction‐fingerprinting

To increase our understanding of Candida pathogenicity, the identification of those strains most frequently associated with infections is of paramount importance. Polymerase chain reaction (PCR)‐based methods are extremely effective in differentiating and determining reproducibility, they require minimum starting material and are rapid and simple to perform. In this study, the genetic relatedness of Candida albicans was assessed for two geographically different patient groups (London, UK and Parma, Italy) affected by diabetes mellitus. C. albicans samples from the oral cavities of non‐diabetic healthy subjects were also examined by PCR fingerprinting to evaluate the possible genetic differences among endogenous strains in individuals with and without diabetes mellitus. PCR fingerprinting, with subsequent phylogenetic analysis of C. albicans isolates from the diabetic patients from London and Italy and from the non‐diabetic subjects, revealed that there were significant differences (P < 0.0001) between C. albicans isolates indicative of the distinct ecological niches that occur in the oral cavities of these patient cohorts. The most diverse group comprised the isolates from the diabetic patients in the UK, possibly reflecting the antifungal treatment that these patients had received. Further studies that include isolates from patient cohorts with systemic diseases other than diabetes mellitus, and from more diverse geographic localities are required to explain the relatedness of C. albicans isolates in the mouth.     

Real‐time RF pulse adjustment for B0 drift correction

Although the magnetic field of an MR scanner is very stable under little or no load, it can become less stable under heavy‐duty cycle conditions, such as in diffusion tensor imaging (DTI). Uncorrected, such field drifts lead to an apparent image shift along the phase‐encoding direction and decreasing effectiveness of fat saturation pulses. A method is presented to adjust the center frequency of all RF pulses and the receiver in real time during the acquisition. No data postprocessing or changes to the sequence timing are necessary. In vivo acquisitions were performed to assess the prolonged effectiveness of fat saturation. Field drifts of approximately 2.5 Hz/min were measured and corrected during DTI acquisitions at b‐values of up to 3000 s/mm². The effectiveness of fat saturation diminished over the duration of an 18‐min acquisition when the drift was left uncorrected. The proposed method corrects for apparent image shift and ensures continuously effective fat saturation over the duration of an acquisition. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.     

SYBR Green Ⅰ实时荧光定量RT-PCR测定猴免疫缺陷病毒RNA拷贝数方法的建立

.学者论坛·在动物实验中解决临床难题···························，·······································································……顾玉东(3)基因〕:程     

间期细胞原位PCR检测B细胞系恶性淋巴瘤

目的：应用原位PCR技术检测B细胞系恶性淋巴瘤。方法：采用免疫球蛋白重链（IgH)基因第三互补决定区（CDR－Ⅲ）的引物，dig-11-dUTP标记物，应用直接原位PCR技术检测Ⅲ-Ⅳ级恶性淋巴瘤的间期淋巴细胞，结果：在初诊的15例恶性淋巴瘤患中，12例检测到IgH基因重排；4例临床表现呈现淋巴瘤性白血病患，治疗后骨髓完全缓解，2例间期细胞原位PCR仍显示有IgH基因重排，6个月复发，结论：间期细胞原位PCR技术能敏感、准确地检测Ⅲ级以上的恶性淋巴瘤，并帮助预测复发，为一有效的基因诊断方法。