人心肌肌钙蛋白Ⅰ基因的人工合成及高效表达

目的人工设计合成完整的人心肌肌钙蛋白I(hcTnI)基因,克隆并在大肠杆菌中获得高效表达。方法根据大肠杆菌遗传密码的偏爱性,人工设计合成hcTnI基因,测序正确后通过DNA重组技术将其插入温控型表达载体pBV220,转化大肠杆菌(E.coli)DH5α,构建cTnI基因的非融合表达菌hcTnI-pBV220/DH5α,热激后诱导非融合蛋白的表达,用单克隆抗体检测特异性hcTnI蛋白表达。结果序列分析表明克隆载体中的cTnI人工基因与设计相符,双酶切电泳结果证明表达载体构建成功,经SDS-PAGE证实重组蛋白的相对分子质量(Mr)约24000,凝胶密度扫描约占菌体总蛋白的25%,能与cTnI单克隆抗体特异性结合。结论成功获得cTnI人工基因,构建了cTnI基因原核表达载体并获得了高效表达,为制备高特异性的抗体及临床检测应用奠定了基础。     

检测MBL EXON Ⅰ 52位密码子突变PCR-SSP方法的建立

目的　建立甘露糖结合凝集素 (MBL) 5 2位密码子基因突变的序列特异性引物聚合酶链反应 (PCR SSP)检测方法。方法　收集静脉血标本 ,提取染色体DNA ,根据MBL基因序列设计引物 ,PCR扩增。结果　扩增产物进行序列分析 ,与预期目的基因序列相同 ,检测灵敏度为 0 .8μg/ml。结论　该方法是一种特异性好、较为灵敏的检测方法。     

Attentional performance of (C57BL/6Jx129Sv)F2 mice in the five-choice serial reaction time task

Impaired attention is evident in several neurological and psychiatric disorders. In the present study, attentional capabilities were measured in the operant five-choice serial reaction time task (5-CSRTT) in male (C57BL/6Jx129Sv)F2 hybrid (B6129F2) mice. Main aims were to validate and standardize the test in these mice: to setup procedures, measure potential beneficial effects of sub-chronic nicotine in degraded versions of the 5-CSRTT (by decreasing stimulus duration, inducing white noise and making the stimuli unpredictable) and study disruptive effects of additional administration of the muscarinic antagonist scopolamine. During the baseline pre-nicotine sessions, the B6129F2 mice attained a very good performance in the test (95% accuracy). As stimulus duration was reduced from 2 s to 1 s, response accuracy of the mice decreased. Mice treated with nicotine (0.16 mg/kg) attained significantly higher response accuracy and had a lower percentage of incorrect responses in comparison with the solvent-treated animals. No further beneficial effects of nicotine were found. Reduced response accuracy was also obtained when stimulus duration was reduced from 1 s to 0.5 s and when a variable intertrial interval was introduced. Noise interpolation between trials did not impair performance. Finally, scopolamine (0.16 mg/kg) disrupted attentional functioning. Although most studies have been performed in rats, these results add to the existing evidence that the 5-CSRTT can also be used to assess attentional performance in mice. This offers the opportunity to test transgenic and knockout mice with similar background as the B6129F2 as animal models of psychiatric and neurological diseases.     

痣样基底细胞癌综合征一家系PTCH1基因突变分析

目的 对痣样基底细胞癌综合征一家系进行PTCH1基因突变分析。 方法 提取先证者（Ⅱ5）及Ⅱ1、Ⅱ3、Ⅲ4的DNA,以50例健康人为对照。应用聚合酶链反应（PCR）、DNA直接测序明确突变位点,根据突变位点设计特异性引物,用PCR来检测突变位点从而进一步确定该家系的致病原因。 结果 先证者PTCH1基因的1条等位基因第14号外显子上2137位胞嘧啶C被胸腺嘧啶T替代（c.2137C > T）,即CAG→TAG,导致终止密码产生（Q714X）,Ⅲ4也检测到相同突变。健康对照者中未检出该突变。 结论 PTCH1基因的无义突变（c.2137C > T）可能是引起该患者临床症状的特异性突变。     

Hyperpolarized 129Xe MRI of the human lung

By permitting direct visualization of the airspaces of the lung, magnetic resonance imaging (MRI) using hyperpolarized gases provides unique strategies for evaluating pulmonary structure and function. Although the vast majority of research in humans has been performed using hyperpolarized ³He, recent contraction in the supply of ³He and consequent increases in price have turned attention to the alternative agent, hyperpolarized ¹²⁹Xe. Compared to ³He, ¹²⁹Xe yields reduced signal due to its smaller magnetic moment. Nonetheless, taking advantage of advances in gas‐polarization technology, recent studies in humans using techniques for measuring ventilation, diffusion, and partial pressure of oxygen have demonstrated results for hyperpolarized ¹²⁹Xe comparable to those previously demonstrated using hyperpolarized ³He. In addition, xenon has the advantage of readily dissolving in lung tissue and blood following inhalation, which makes hyperpolarized ¹²⁹Xe particularly attractive for exploring certain characteristics of lung function, such as gas exchange and uptake, which cannot be accessed using ³He. Preliminary results from methods for imaging ¹²⁹Xe dissolved in the human lung suggest that these approaches will provide new opportunities for quantifying relationships among gas delivery, exchange, and transport, and thus show substantial potential to broaden our understanding of lung disease. Finally, recent changes in the commercial landscape of the hyperpolarized‐gas field now make it possible for this innovative technology to move beyond the research laboratory. J. Magn. Reson. Imaging 2013;37:313–331. © 2012 Wiley Periodicals, Inc.     

32‐channel phased‐array receive with asymmetric birdcage transmit coil for hyperpolarized xenon‐129 lung imaging

Hyperpolarized xenon‐129 has the potential to become a noninvasive contrast agent for lung MRI. In addition to its utility for imaging of ventilated airspaces, the property of xenon to dissolve in lung tissue and blood upon inhalation provides the opportunity to study gas exchange. Implementations of imaging protocols for obtaining regional parameters that exploit the dissolved phase are limited by the available signal‐to‐noise ratio, excitation homogeneity, and length of acquisition times. To address these challenges, a 32‐channel receive‐array coil complemented by an asymmetric birdcage transmit coil tuned to the hyperpolarized xenon‐129 resonance at 3 T was developed. First results of spin‐density imaging in healthy subjects and subjects with obstructive lung disease demonstrated the improvements in image quality by high‐resolution ventilation images with high signal‐to‐noise ratio. Parallel imaging performance of the phased‐array coil was demonstrated by acceleration factors up to three in 2D acquisitions and up to six in 3D acquisitions. Transmit‐field maps showed a regional variation of only 8% across the whole lung. The newly developed phased‐array receive coil with the birdcage transmit coil will lead to an improvement in existing imaging protocols, but moreover enable the development of new, functional lung imaging protocols based on the improvements in excitation homogeneity, signal‐to‐noise ratio, and acquisition speed. Magn Reson Med 70:576–583, 2013. © 2012 Wiley Periodicals, Inc.