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Cardiac pacing is a medical device to help human to overcome arrhythmia and to recover the regular beats of heart. A helical
configuration of electrode tip is a new type of cardiac pacing lead distal tip. The helical electrode attaches itself to the
desired site of heart by screwing its helical tip into the myocardium. In vivo experiments on anesthetized dogs were carried
out to measure the acute interactions between helical electrode and myocardium during screw-in and pull-out processes. These
data would be helpful for electrode tip design and electrode/myocardium adherence safety evaluation. They also provide reliability
data for clinical site choice of human heart to implant and to fix the pacing lead. A special design of the helical tip using
strain gauges is instrumented for the measurement of the screw-in and pull-out forces. We obtained the data of screw-in torques
and pull-out forces for five different types of helical electrodes at nine designed sites on ten canine hearts. The results
indicate that the screw-in torques increased steplike while the torque–time curves presente saw-tooth fashion. The maximum
torque has a range of 0.3–1.9 N mm. Obvious differences are observed for different types of helical tips and for different
test sites. Large pull-out forces are frequently obtained at epicardium of left ventricle and right ventricle lateral wall,
and the forces obtained at right ventricle apex and outflow tract of right ventricle are normally small. The differences in
pull-out forces are dictated by the geometrical configuration of helix and regional structures of heart muscle. 相似文献
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本次研究目的是探讨CT灌注成像(CTP)联合微小核糖核酸-195(miR-195)在急性脑梗死诊断及预后判断中的价值。选取158例急性脑梗死患者作为观察组,100例健康体检者作为对照组,采用PCR法检测两组血清miR-195水平,比较观察组不同患者梗死区脑血流量(CBF)、脑血容量(CBV)、对比剂平均通过时间(MTT)、达峰时间(TTP)的差异,同时分析各参数预测预后不良的价值。观察组血清miR-195水平明显高于对照组(P<0.05);NIHSS评分≥5分、预后不良患者梗死区CBF、CBV、MTT、TTP明显低于NIHSS评分<5分、预后良好患者(P<0.05),而TTP、血清miR-195相对表达量明显高于NIHSS评分<5分、预后良好患者(P<0.05)。CBF、CBV、MTT与NIHSS评分呈负相关(P<0.05),TTP、血清miR-195相对表达量与NIHSS评分呈正相关(P<0.05)。CBF、CBV、MTT、TTP、miR-195及联合预测急性脑梗死预后不良的ROC曲线下面积分别为0.685、0.867、0.630、0.736... 相似文献
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本文研究了3D动脉自旋标记灌注成像(3D-ASL)评估慢性期脑梗死脑血流量(CBF)及与认知功能的相关性。选取64例慢性期脑梗死患者作为慢性期组,同时选取60例急性期脑梗死患者作为急性期组,50例亚急性期脑梗死患者作为亚急性期组,比较三组患侧及健侧CBF、相对脑血流量(rCBF)差异。慢性期组患侧CBF、rCBF明显低于亚急性期组和急性期组(P<0.05)。慢性期组患者简易智能精神状态量表(MMSE)评分、蒙特利尔认知评估量表(MoCA)评分和Fugl-Meyer评分明显低于亚急性期组和急性期组(P<0.05)。患侧CBF、rCBF与MMSE评分、MoCA评分呈正相关(P<0.05)。经Logistic回归分析显示:年龄、糖尿病、患侧CBF和rCBF是慢性期脑梗死患者发生认知功能障碍的影响因素(P<0.05)。慢性期脑梗死患者CBF与患者认知功能相关,3D-ASL评估CBF有助于了解慢性期脑梗死患者认知功能受损情况。 相似文献
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A series of modified poly (methyl methacrylate, PMMA) resins were prepared and compared their adsorption abilities to endotoxin. The results showed that adsorbents, which were grafted with tertiary amine and long spacing arms, had the best adsorption capacities and good blood compatibility, It is hopeful to be used as adsorbent in hemoperfusion for clinical clearance of endotoxin. The influence of original concentration of endotoxin on adsorption and the adsorption mechanism were also investigated. 相似文献
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对157例胃肠道癌切除术后病人, 随机分成术中腹腔温热灌洗化疗联合术后置泵持续动脉灌注及静脉微泵化疗组72例(简称治疗组)、单纯静脉化疗组85例(简称对照组), 并对其腹腔转移率、 肝转移率及3 a生存率进行对照研究, 取得了较满意的临床疗效。 术中腹腔温热灌洗化疗联合术后置泵持续动脉灌注及静脉微泵化疗三途径综合治疗对胃肠道癌病人术后腹腔转移及肝转移有良好的防治作用。 157 cases of gastrointestinal cancer patients after resection were randomly divided into treated group and control group. The treated group (intraperitoneal hyperthermic perfusion chemotherapy combined with postoperative continuous intraarterial infusion and intravenous micro pump chemotherapy) consisted of 72 cases, the control group (Intravenous chemotherapy), 85 cases. The peritoneal and hepatic metastasis rates and 3 a survival rate were studied. The intraperitoneal hyperthermic perfusion chemotherapy combined with the postoperative continuous intraarterial infusion and intravenous micro pump chemotherapy is an effective way to control the recurrence on the peritoneal and hepatic metastasis of advanced gastrointestinal neoplasms after operation. 相似文献
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目的探讨急诊科预先启动导管室对ST段抬高心肌梗死(STEMI)患者再灌注时间及心肌损伤标志物水平的影响.方法选择2009-01—2010-06成功行急诊PCI的STEMI患者124例.按不同导管室启动模式分为A组54例和B组70例.A组:急诊科医师初步诊断STEMI后通知心内科医师会诊,后者确认后再通过导管室负责人并启动导管室;B组:急诊科医师初步诊断STEMI后直接通知导管室负责人,后者派心内科医师会诊的同时启动导管室.主要分析指标为急诊PCI相关时间:门-球囊(D2B)时间,门-心电图(D2E)时间,心电图-导管室(E2L)时间,导管室-球囊(L2B)时间.次要分析指标:CK-MB、肌钙蛋白I (cTnI)峰值.结果两组临床资料及冠状动脉造影(CAG)结果差异无统计学意义(均P>0.05).与A组相比,B组D2B时间缩短[ 相似文献