Is the knowledge of contact force beneficial in pulmonary vein antrum isolation?

Objective: To investigate the effect of the operator knowing the real-time contact force (CF) on the efficacy of pulmonary vein antrum isolation (PVAI).

Methods: Fifty patients with paroxysmal atrial fibrillation (AF) or short lasting persistent AF were randomized to CF guided PVAI (n?=?25) or conventional PVAI (n?=?25). In the CF guided group, CF between 10 and 40?g was aimed at. Efficacy of PVAI was measured as reduction in AF burden (AFB) and time to AF recurrence detected by implantable cardiac monitor (ICM), inserted three months before PVAI. Blanking period was three months and follow-up 12 months.

Results: All pulmonary veins were isolated in the CF guided group and all but one in the conventional group. Mean CF was 25?g in the CF guided group and 24?g in the conventional group (p?=?0.75). Compared to pre-ablation, median [IQR] relative reduction in AFB 3–12 months after ablation was 100 [99–100]% in the CF guided group (p?p?p?=?0.09). Nine patients (36%) had AF recurrence in the CF guided group and 13 (52%) in the conventional group (p?=?0.21, log-rank test). CF differed between operators. When adjusted for operator by regression analysis, patients without recurrent AF had lower proportion of ablation time with CF <10?g than recurrent patients (p?=?0.034). No complications occurred.

Conclusions: Operator knowledge of real-time CF had no significant effect on AFB reduction or time to AF recurrence. Larger trials should be done to study benefit of real-time CF.     

Effect of body position on qualitative and quantitative ultrasound assessment of gastric fluid contents

We assessed the impact of raising the upper section of the bed, and patient positioning, on ultrasound assessment of gastric fluid contents. We performed ultrasound examinations in 25 subjects lying on their back, left and right sides at bed angles of 0°, 30°, 45° and 90°; this was carried out while the subjects were fasted, and repeated 10 min after drinking ≥ 50 ml water. After drinking, gastric contents were detected more frequently in the 45° semirecumbent position compared with the supine and 30° positions. The diagnostic performance of the Perlas qualitative grading scale to detect gastric fluid volume > 1.5 ml.kg⁻¹ was improved at 45°, compared with 0° and 30° angles. The use of a composite ultrasound grading scale at a 45° angle was associated with the best performance, with a sensitivity and specificity of 82%. Antral cross-sectional area was significantly increased when measured in the right lateral position, but there was no effect of raising the bed. In conclusion, raising the upper section of the bed significantly affected qualitative assessment of gastric fluid contents. Further studies are required to determine the most appropriate composite ultrasound grading scale and bed angle for fast and reliable qualitative ultrasound detection of fluid volumes > 1.5 ml.kg⁻¹.     

电针对犬幽门括约肌压力的影响及作用机制

目的观察电针（electroacupuncture,EA）对犬幽门括约肌压力的调控作用及其与血浆、胃粘膜组织中降钙素基因相关肽（calcitonin gene-related peptide,CGRP）、内皮素（endothelin,ET）含量变化的关系,探讨电针调控胃功能的作用机制。方法将20只犬随机分为4组：空白对照组、非经非穴组、上巨虚组、足三里组（每组5只）。采用胃压测量仪监测犬幽门括约肌压力的变化,同步测定血浆及胃粘膜组织中CGRP、ET含量,并观察变化规律。结果电针足三里穴后幽门扩约肌总压力、基础压（P〈0．01）、频率下降（P〈0．05）,血浆及胃粘膜组织中CGRP含量上升（P〈0．01）,ET含量显著下降（P〈0．01）,上巨虚穴组幽门扩约肌总压力、基础压下降,仅血浆CGRP（P〈0．05）含量上升,内皮素含量下降,但足三里组变化趋势更明显,其他组各监测指标无显著变化。结论电针可使犬幽门括约肌压力变化,对部分胃功能具有调控作用,并与影响某些脑肠肽的含量改变有关,具有一定的经络和穴位特异性。     

实验性脾气虚大鼠胃泌素的基因表达及四君子汤的干预作用

目的:观察脾气虚证大鼠胃窦黏膜胃泌素(gastrin,GAS)基因表达的改变及不同用药时间段四君子汤对其调整作用,探讨脾气虚证的本质及四君子汤的作用机制。方法:以三因素复合的方法复制脾气虚证大鼠模型,造模大鼠随机分成模型组、四君子汤组,在干预后不同时间段,用逆转录聚合酶链反应方法(RT-PCR)检测四君子汤对脾气虚大鼠胃窦GAS mRNA表达的影响。结果:脾气虚模型组血清GAS水平、胃窦GAS mRNA表达下降,与正常组比较差异有显著性(P<0.05);四君子汤组血清GAS含量、胃窦GAS mRNA表达随用药时间的延长呈递增的趋势,用药21天时,与模型组比较,差异有显著性(P<0.05)。结论:GASmRNA表达失衡是脾气虚证的本质之一,而四君子汤上调GAS mRNA表达是其治疗脾气虚证的机制之一。     

不饱和脂肪酸对豚鼠胃窦环行肌细胞毒蕈碱电流的影响

目的：研究外源性不饱和脂肪酸对豚鼠胃窦平滑肌细胞素毒蕈碱电流的影响及其作用机制。方法：利用膜片箝技术的全细胞记录法在急性分离的胃窦环行肌细胞上记录毒蕈碱电流。结果：在细胞外灌流液中给予花生四烯酸（arachidonic acid,AA）明显抑制I_cch,并具有量效关系：当AA的浓度在1。3和μmo1/L时,分别抑制I_cch至46%±8%,23%±5%和3.8%±0.9%;另一种不饱和脂肪酸,亚麻酸（linoleic acid,LA）也抑制I_cch,在1,5和10μmo1/L浓度分别抑制I_cch至3.8%±0.9%,35%±5%和67%±9%;用H-7（蛋白激酶C抑制剂）100μmo1/L预处理10-15分钟以后,AA分别抑制I_cch至5.5%±0.7%和3.0%±1.0%。结论：不饱和脂肪酸直抑制毒蕈碱电流,且抑制程度与不饱和脂肪酸链中的双键数目有关。     

In vitro evaluation of ultrasound Doppler strain rate imaging: modification for measurement in a slowly moving tissue phantom

Doppler strain rate imaging (SRI) was evaluated in vitro using a silicone strip phantom mimicking slowly moving tissue. A test apparatus was developed that enabled controlled strain experiments with variable strain and strain rate to be performed. SRI strain was measured at eight different calculated strains (range 5.7 to 63.4 %) at three different pump speeds with tissue velocity 0.1, 0.5 and 1.0 mm/s. The effect of varying tissue velocity and strain sample size on the measured SRI strain was elaborated. SRI strains agreed well with calculated values for strain when SRI strain was measured as the average over the whole strip cross-section and the strain sample size was 1.9 mm (mean DIFFERENCE = 2.78%, limits of agreement ± 9.97% for tissue velocity 1.0 mm/s, n = 8). The variance was substantial if single central samples were used, especially for strain sample size of 0.8 mm (mean DIFFERENCE = −7.47%, limits of agreement ± 20.90 for tissue velocity 0.5 mm/s, n = 24). Increasing the strain sample size to 1.9 mm removed some of the underestimation (giving mean difference of −4.46%, n = 24). We found low intra- and interobserver variation. This study indicates that, for the SRI method to give accurate estimates of strain, strain sample size should be in the region of 2 mm. Averaging over several ultrasound (US) beams increased the accuracy further.(E-mail: Knut.Matre@med.uib.no)     

健脾消痞方联合推拿对厌食症胃肠动力、Cajal间质细胞自噬的影响

目的：基于促分裂原活化的蛋白激酶（MAPK/MEK）/胞外信号调节激酶1/2（ERK1/2）信号通路分析健脾消痞方联合推拿疗法对厌食症幼鼠胃肠动力及胃窦Cajal间质细胞自噬的作用机制。方法：无特定病原体（SPF）级SD健康幼鼠50只随机分为健康组、模型组（小儿厌食症模型）、中药组（模型+健脾消痞方干预）、联合组（模型+健脾消痞方+推拿疗法干预）,每组10只。另10只大鼠建立小儿厌食症模型给予MEK/ERK信号通路抑制剂PD98059进行注射作为抑制剂组。每2周测量幼鼠体质量和摄食量;比色法测血清淀粉酶水平;放射免疫法测血清胃泌素水平;苏木精-伊红（HE）染色观察病理形态;实时PCR检测Cajal间质细胞标志物氨酸蛋白激酶生长因子受体（c-kit）、微管相关蛋白轻链3（LC3）、自噬基因苄氯素1(Beclin1)基因表达。蛋白印迹检测MEK、ERK1/2、p-MEK、p-ERK1/2蛋白表达。结果：与健康组比较,模型组幼鼠体质量、体质量增长率、摄食量、c-Kit、小肠推进比、血清淀粉酶、血清胃泌素降低,MEK、ERK1/2、LC3、Beclin1、胃内残留水平升高（P<0.05）。在经过中药组及联合组干预后,幼鼠体质量、体质量增长率、摄食量、c-Kit、小肠推进比、血清淀粉酶、血清胃泌素升高,MEK、ERK1/2、LC3、Beclin1、胃内残留水平降低（P<0.05）,且联合组较中药组效果更佳（P<0.05）。联合组与抑制剂组幼鼠蛋白表达比较,差异无统计学意义（P>0.05）.结论：健脾消痞方联合推拿可能是通过抑制MEK-ERK1/2信号通路激活,从而抑制胃窦Cajal间质细胞自噬,改善胃肠道功能。     

缺血性脑卒中大鼠不同时期胃窦cajal问质细胞的变化

目的研究脑卒中大鼠不同时期胃窦cajal间质细胞（ICC）的表达与变化。方法将40只雄性大鼠随机分为3组,即对照组、假手术组、缺血性脑卒中模型组,缺血性脑卒中模型组又根据实验终止时间分为3个亚组（1d组、3d组、7d组）,每组8只。采用改良的线栓法建立大鼠大脑中动脉闭塞模型．分别于缺血后1、3、7d处死相应模型组大鼠。假手术组仅切开皮肤,不放线栓。用免疫组化法检测胃窦酪氨酸激酶受体阳性ICC含量的变化。结果脑卒中后大鼠胃窦的ICC总数有减少,以脑卒中后3d组减少的最多（P〈0．01）,脑卒中不同时期对胃窦ICC总数有显著影响（P〈0．01）。胃窦各层ICC数量在脑卒中后以黏膜下ICC（ICC—SM）减少明显（P〈0．01）,肌内ICC（ICC—IM）仅在脑卒中后3d减少（P〈0．05）,而肌间ICC、深肌丛ICC受影响轻微。结论缺血性脑卒中后大鼠胃窦的ICC总数有减少,以ICC—SM明显,其次是ICC-IM,ICC数量的变化是脑卒中后胃肠功能紊乱的原因之一。     

实时超声法研究正常男女胃液体排空功能

采用实时超声法研究５０例成年正常男女胃液体排空，发现：其排空率随餐后时间的延长而下降，且胃底－体部的变化较幽门窦显著。在餐后３０ｍｉｎ内，男性受试者的胃底－体部的排空率大于女性受试者。只发现女性受试者胃底－体部和幽门窦的宽径与年龄呈负相关。为便于今后研究，分别拟合男女性胃底－体部随餐后时间变化的数学模型。     

实时超声法研究正常男女胃液体排空功能

采用实时超声法研究了５０例成年正常男女胃液体排空。发现：其排空率随餐后时间的延长而下降，且胃底 体部的变化较胃窦显著。在餐后３０ｍｉｎ内，男性受试者的胃底 体部的排空率大于女性。只发现女性受试者胃底 体部和胃窦的宽径与年龄呈负相关。分别拟合男女性胃底 体部随餐后时间变化的数学模型。