Artery and vein separation using susceptibility-dependent phase in contrast-enhanced MRA

In magnetic resonance angiography, contrast agents are frequently used to help highlight arteries over background tissue. Unfortunately, enhancing veins hamper the visualization of arteries when data are collected over a long period of time after the arterial phase of the contrast agent. To overcome this problem, we have developed a novel imaging and postprocessing method that is capable of eliminating veins by utilizing the susceptibility difference between veins and surrounding tissue. This method was applied in the peripheral vasculature where the vessels are predominantly parallel to the main field and where the blood oxygen level-dependent effect is most pronounced. Results are presented for both long (15.8 msec) and short echo times (7.8 msec) and for sequential and centrally reordered acquisition schemes. The short echo scan approach appears to be the most promising, making it possible to obtain good suppression of the venous signal even when the timing is not perfect or when repeat scans are necessary.     

Delayed Administration of the K+ Channel Activator Cromakalim Attenuates Cerebral Vasospasm after Experimental Subarachnoid Hemorrhage

Summary ? Background. Delayed cerebral vasospasm remains an unpredictable and inadequately treated complication of aneurysmal subarachnoid hemorrhage (SAH). Recent evidence indicates that the potassium channel activator cromakalim is capable of limiting cerebral vasospasm in rabbits when administered immediately after experimental SAH (i.e. before spastic constriction has been initiated). However, the ultimate clinical value of cromakalim for treating vasospasm will depend in part on its effectiveness when administered after SAH-induced constriction has already been initiated. The present study examined the effects of cromakalim on vasospasm when treatment was initiated after SAH-induced constriction was underway.  Methods. New Zealand white rabbits were subjected to experimental SAH by injecting autologous blood into the cisterna magna. Cromakalim (0.03, 0.1 or 0.3 mg/kg) or vehicle was injected intravenously at 8 hour intervals beginning 24 hours post-SAH. Animals were killed by perfusion fixation 48 hours after SAH. Basilar arteries were removed and sectioned, and cross-sectional area was measured.  Findings. The average cross sectional areas of basilar arteries were reduced by 64% and 68% in the SAH-only and SAH+vehicle groups, respectively. Treatment with cromakalim dose-dependently attenuated SAH-induced constriction. The groups treated with 0.03, 0.1, and 0.3 mg/kg cromakalim exhibited average decreases in cross-sectional area of 57%, 42%, and 19%, respectively.  Interpretation. These findings indicate that cromakalim dose-dependently attenuates cerebral vasospasm when administered 24 hours after experimental SAH in the rabbit. The results suggest K_ATP channel activators, such as cromakalim, could be of benefit for reversing cerebral vasospasm after aneurysmal SAH.     

Graft failure caused by pulmonary venous obstruction diagnosed by intraoperative transesophageal echocardiography during lung transplantation

IMPLICATIONS: Intraoperative transesophageal echocardiography can be useful to diagnose pulmonary venous anastomotic stenoses during lung transplantation.     

原花青素和丹酚酸对果蝇等动物抗氧化指标及存活时间的影响

[目的 ]探讨原花青素和丹酚酸 (ProanthocyanidirandSalvianolicacid ,PS)胶囊对果蝇、12月龄大鼠、ICR小鼠的寿命、抗氧化性及存活时间的影响。 [方法 ]采用果蝇生存、抗氧化和耐缺氧实验方法观察果蝇、大鼠、小鼠生存时间及脂质过氧化指标。果蝇喂饲PS剂量为 0 0 12 %、0 .0 3 6%、0 .10 8%和 0 .3 2 4% ,大鼠、小鼠均以 0 .0 9、0 .18、0 .3 6g/(kg·bw)PS胶囊剂量连续灌胃 1～ 2个月。 [结果 ]各剂量PS胶囊组动物与对照组比较能明显延长果蝇的半数死亡时间 ( 0～ 4.0d)、平均寿命 ( 0 .4～ 4.0 4d)和平均最高寿命 ( 0 .8～ 4.8d) ;能明显提高 12月龄大鼠血清SOD的活力 8.8～ 15 .5NU/ml,降低MDA的含量 0 .8～ 0 .98nmol/ml ;能明显延长ICR小鼠常压下缺氧的存活时间 ( 4 2 0～ 777s)、亚硝酸钠中毒致死的存活时间 ( 184～ 966s)及急性脑缺血性缺氧的喘气时间 ( 2 .3～ 4.4s)。 [结论 ]提示原花青素和丹酚酸为主要成分的PS胶囊具有延缓动物衰老作用及增强耐受力的作用。     

微流芯片检测流感病毒多重逆转录聚合酶链反应产物的实验研究

[目的 ]　建立应用微流芯片检测甲 1型、甲 3型、乙型流感病毒多重逆转录聚合酶链反应 (mRT -PCR)产物的方法 ,在mRT -PCR扩增核酸的基础上自动化灵敏的定量检测扩增产物 ,快速检测甲亚型、乙型流感病毒 ,帮助临床快速诊断和鉴别诊断其他呼吸道病毒感染 ,以及明确流感病毒在人群中感染、流行情况。　 [方法 ]　采用经MDCK细胞分离培养的甲 1型、甲 3型、乙型流感病毒毒株病毒液 ,使用 3组特异引物经mRT -PCR扩增核酸 ,扩增产物分别采用毛细管电泳技术经Caliper10 0 0微流芯片分析仪自动化检测和经 2 %琼脂糖凝胶电泳法检测。　[结果 ]　设计三组引物对相应甲 1型、甲 3型、乙型流感病毒靶基因的mRT -PCR扩增产物片段分别为 43 0bp、2 10bp、3 91bp ,本实验mRT -PCR扩增产物经 2 %琼脂糖凝胶电泳 ,与Marker比照 ,DNA条带基本在此位点附近 ;产物采用毛细管电泳法经Caliper10 0 0微流芯片分析仪后 ,分别于 413bp、2 0 3bp、3 79bp处出现陡峭的峰 ,如图所示。　[结论 ]　应用微流芯片采用毛细管电泳法可对流感病毒mRT -PCR产物进行定位及相对定量 ,有助于快速诊断流感病毒感染 ,有助于对流感的监测。     

深圳市艾滋病分子流行病学和HIV膜蛋白基因变异与感染时间相关性分析

目的:对深圳市HIV感染流行趋势分析,为深圳市艾滋病防治策略提供依据.方法:对1992～2000年深圳市HIV血清学监测质料及应用套式PCR(nested-PCR)对深圳市55例HIV感染者/AIDS病人的外周血的单核细胞进行扩增,获得了HIV-1膜蛋白(env)基因的核酸片段,并对其C2-C3区进行测定和分析.结果:深圳市疫情快速增长趋势明显;传播方式以性为主(46.0%)其它各种HIV传播途径均有发现;有B′、B、C、E亚型HIV-1毒株序列,各亚型间的基因离散率为6.31%、7.95%、3.09%、8.92%,推算其流行时间为6,8,3,9年,深圳流行株以E、B为主,且AIDS病人抗原性变异较高于HIV感染者.结论:监测数据可反映深圳市HIV感染流行主流,可预测流行趋势.     

江门市3～6岁异常视力儿童屈光状态分析

目的了解江门市异常视力儿童屈光状态。方法对江门市幼儿园的8510名3～6岁儿童进行视力普查。对单眼裸眼视力<0.9者(1116例2232只眼)的屈光状态及弱视患儿的屈光状态进行了分析。结果屈光不正总患病率为13.01%;远视、混合散光、近视患病率依次为9.85%、2.36%、0.80%(P<0.05);轻、中、重度屈光不正患病率依次为7.34%、3.96%、1.70%(P<0.05);屈光不正有年龄特点(4岁组患病率高于其他年龄组);弱视患病率为3.74%;弱视首次检出率为88.23%。结论远视性屈光不正是导致弱视的主要原因。     

注意力缺陷及注意缺陷多动障碍患儿局部脑血流灌注的研究

【目的】探讨注意缺陷／多动障碍(ADHD)各亚型局部脑血流(rCBF)特点以及与不同临床类型的关系。【方法】用单光子发射计算机断层扫描(SPECT)测定了40例ADHD患儿和11例正常儿童rCBF灌注情况。【结果】定性分析结果显示，ADHD患儿低疋BF灌注量的发生率(57．5％)高于正常儿童(9％)，低灌注部位涉及额叶、颞叶、枕叶和丘脑，以额叶发生率最高；伴有多动一冲动组低rCBF注量的发生率(66．7％)高于注意缺陷组(47．3％)，同时，伴有多动一冲动组中在所有疋BF降低的脑区中，左侧占14例次，右侧占10例次，左右侧rCBF差异有显著性。【结论】额叶rCBF降低与ADHD行为抑制缺陷相关，同时左侧脑区血流下降与病情的严重程度相关。     

Firebird冠脉涂膜支架系统生物学安全性评价研究

依据国家标准GB/T16175-1996,选择10项试验对Firebird冠脉涂膜支架系统进行生物学安全性评价[1],结果表明该支架系统的血液相容性良好,无全身毒性和细胞毒性,无热源性、致敏性、刺激性,也无遗传毒性,组织相容性尚可,是一种生物相容性优良的Firebird冠脉涂膜支架系统.     

药品集中招标采购:公共政策分析与求解

针对我国药品集中招标采购实施过程中的现实困境,文章从利益主体各方力量严重失衡、中介代理机构外部力量失效等角度作出政策分析.在此基础上,作者考量和判断了药品集中招标采购政策的改革形势,并从制度本身的完善、相关制度改革的深化以及政府监管等方面提出对策建议.