射频组织焊接技术用于结直肠吻合的探索性研究

利用射频能量焊接肠组织,研究压合压强、功率、温度参数对焊接效果的影响.利用自制的焊接器械和射频能量平台,进行焊接猪离体结直肠组织实验.实验参数为:射频频率450 kHz,输出功率恒定(50和70 W),在压合压强(l 125和2 658 kPa)下持续焊接肠组织240 s,控制焊接过程中的最高温度为(95±5)℃.实验完成后通过组织病理切片对比不同条件下肠道焊接的牢固程度、热损伤情况.结果表明:在50和70 W功率下,压合压强1125 kPa的组,焊接部位浆膜层紧紧贴合,周围组织结构保持完好；压合压强2 658 kPa的组,焊接部位浆膜层未完全融合,且周围黏膜损伤较明显.最高焊接温度控制在(95±5)℃时,功率50和70 W的组焊接效果在组织病理切片观察中无明显差异.射频能量焊接结直肠可行性良好,但压合压强过大易导致焊接部位周围组织损伤；且考虑到焊接部位周围的温度分布不均匀,不可单一用温度参数作为判断焊接效果的标准.     

基于射频能量的肠道组织焊接研究

目的 在射频能量的作用下，通过新型压力可控电极对猪小肠(回肠部分)进行焊接，验证能量组织焊接技术对于肠道结构重建的可行性和安全性。方法 将新鲜猪小肠按“黏膜-浆膜”嵌套在负电极上，通过施压圆锥体对正电极施加不同的压合压强（497、796、995、1 194、1 492 kPa），在射频能量作用下完成肠道组织的焊接，通过撕脱力和爆破压测试研究焊接吻合口的生物力学特性，并对组织热扩散和微观组织结构进行检查。结果 在能量输出功率160 W，压合压强995 kPa，焊接时间为13 s时，肠道吻合口呈现最优的生物力学特性，其撕脱力和爆破压分别达到(8.73±1.11) N和(8.29±0.41) kPa，且组织微观结构较完整，并能观察到少量游离胶原蛋白。结论 射频能量组织焊接技术具有良好的应用前景，能够实现肠道组织快速、稳定的连接，对缩短手术时间、简化操作流程并提高手术质量,具有重要意义。     

新型射频组织焊接电极的设计、仿真与实验研究

目的 设计一种新型射频组织焊接电极,提高吻合口生物力学强度的同时减少组织热损伤。 方法 设计表面存在镂空结构的新型电极(梅花形电极),以环形电极作为对照组,在射频能量作用下完成肠道组织焊接,通过撕脱力和爆破压测试研究焊接吻合口的生物力学特性,采用有限元电-热-力多场耦合仿真分析和热电偶探针研究焊 接过程中的组织热损伤,并对微观组织结构进行检查。 结果 当焊接功率 120 W、焊接时间 8 s、压合压强 20 kPa时,肠道吻合口呈现最优的生物力学特性。 与环形电极对照组相比,梅花形电极组吻合口生物力学强度更高,撕脱力和爆破压分别从(8. 62±1. 22) N、(81. 7±3. 36) mmHg 增加到 (9. 54±1. 24) N、(89. 4±4. 15) mmHg,且组织热损伤显著减少,组织微观结构连接更为紧密。 结论 该新型电极在提高吻合口生物力学强度的同时可减少组织热损伤,进而实现更好的吻合效果。 研究结果可为实现人体管腔组织的无缝连接提供参考。     

基于自冷却焊接钳口的小肠组织射频焊接参数优化研究

本研究利用新型具有冷却效果的焊接钳口,配合自制的射频能量平台对离体猪小肠进行实验,以探索适用于自冷却焊接钳口的焊接模式及参数。本研究以爆破压和热损伤作为评判依据,通过改变不同输出功率和不同能量输出模式,评估其闭合质量。结果显示,在持续输出模式下,125 W为较优功率参数,爆破压为(44.94±2.93) mmHg,平均热损伤为(2.26±0.16) mm;在断续输出模式下,“输出1 s,暂停0.5 s,循环10次”为较优焊接参数,爆破压为(47.71±4.08) mmHg,平均热损伤为(1.95±0.43) mm。实验结果表明,该射频焊接平台可实现质量良好的闭合,相较于持续输出模式,使用合适参数的断续输出模式在提升爆破压的同时,可以较低的热损伤实现猪小肠闭合。     

射频能量肠道焊接技术的研究进展

肠道吻合是肠道外科手术中的重要环节,其吻合效果直接关系到手术完成的质量和患者术后的恢复状况。近年来,射频能量肠道焊接技术以其无针创、弱炎性反应、易于控制、操作简便等特性,受到国内外学者的重视。虽然该技术具有巨大的发展潜力,但目前各研究团队的相关工作相对比较分散。本文对该技术的研究进展及方向进行了综述,以期为相关研究人员提供一定的借鉴作用。     

应用软组织高频焊接仪闭合小肠的可行性研究

本研究旨在评价软组织高频焊接仪闭合小肠的可行性及有效性。取100根猪小肠随机分为实验组与对照组,每组50根。实验组使用焊接仪闭合小肠,测量闭合肠管所用时间、热损伤范围、闭合处最高温度和闭合后肠管爆破压,并取闭合处组织进行病理切片检查;对照组采用手工缝合法闭合小肠,记录闭合肠管时间和闭合处爆破压。结果发现软组织高频焊接仪闭合新鲜猪小肠50根,闭合成功率达100%,两组闭合肠管时间、爆破压差异存在统计学意义(P0.01)。闭合处主要病理改变为组织的急性热损伤及压力损伤。结果表明软组织高频焊接仪闭合小肠具有较高的可行性。     

子宫内膜双极多探针射频消融的有限元分析

目的运用有限元方法模拟子宫内膜射频消融过程中的温度场分布,为提高子宫内膜射频消融术的安全性和治疗效果提供理论依据。方法以三种常见大小的子宫腔为研究对象,根据生物热方程建立了子宫内膜的射频消融有限元模型,分析射频消融过程中靶向组织的最高温度、最低温度的变化,以及损伤面积和深度随子宫大小和射频电压（功率）不同产生的变化。结果电压不变、子宫尺寸变大时,最高温度变化较小,最低温度变小,损伤面增加但深度减小。子宫腔尺寸不变,功率变大时,最高温度增大,最低温度变化较小,损伤面积增加,深度增大。结论子宫内膜射频消融手术中同时考虑子宫腔大小和射频电压具有临床参考价值。     

脑组织射频消融的有限元仿真与分析

目的 运用有限元方法（finite element method,FEM）模拟颅内病灶射频消融过程中的温度场分布,以合理有效利用热疗方案,提高射频消融对颅内病灶的治疗效果.方法 建立电导率不变和电导率随温度变化的两种有限元模型,并对两种模型的中心温度、电场强度、热生成率、比吸收率（specific absorption rate,SAR）,以及热损伤区域进行对比分析.结果 对比电导率不变的有限元模型,在电导率随温度变化的情况下,电场强度减小,电流密度增大,中心温度升高,热损伤范围增大;当消融温度接近100 ℃时电导率变化明显,其对消融效果影响较大.结论 射频热疗手术中考虑随温度变化的组织参数有较高的临床参考价值.     

心脏射频消融术中心包压塞的临床诊治特点分析

目的：探讨心脏射频消融术中心包压塞的临床特点以及诊治过程。方法：对射频消融术中出现心包压塞的21例病例的病历资料及填塞时临床表现、诊断和处理、预后情况等进行回顾性分析,分析出现心包压塞患者的临床特点。结果：随着术者学习曲线的延伸,房颤和室性心律失常术中心包压塞发生率逐渐减低;女性患者心包压塞的发生率高于男性(5.4‰ vs.1.2‰,P<0.05),尤其在室性心律失常的射频中更为明显(9.0‰ vs.1.2‰,P<0.05);射频消融患者中,心包压塞患者年龄可能更大,尤其是室性心律失常患者中(P<0.05);心包压塞发生时,最先出现的、容易观察到的临床表现多为心率加快和血压下降(76.2%);心包压塞患者中,穿刺引流后痊愈者平均出血量(297.6±270.7) mL,需行外科手术患者的平均出血量更多,为(1570.0±720.5) mL (P<0.05)。结论：射频消融术中心包压塞的发生与学习曲线、性别、年龄均相关,应通过临床表现、X线透视等及早发现心包压塞并及时治疗。     

呼吸过程胸膜腔内压和肺泡壁压强的产生与变化规律

生理学教科书都论及胸膜腔压强、肺泡壁压强和肺内压,但都未阐明清楚。本研究揭示胸膜腔内压、肺泡壁压强和肺泡内压的产生及变化规律。结果表明,胸膜腔内压是肺胸膜所受扩张力或压缩力的压强产生。平静吸气时,胸廓扩张,胸膜腔负压增大。平静呼气时,胸廓缩小,但胸廓、肺仍处于扩张状态,胸膜腔内仍为负压。随着胸廓缩小,负压减小。在用力呼气时肺胸膜、壁胸膜挤压胸膜腔,其内才产生正压。肺泡壁压强是胸膜腔内压、肺组织内的压强与肺泡壁附加压强的代数和。肺泡壁附加压强用球形弹性膜拉普拉斯公式计算。肺泡内压取决于肺泡壁张缩运动快慢和气道阻力大小。     

Computer analysis of mechanical and electrical uterine activity

To facilitate the study of myometrial activity two algorithms were developed for continuous analysis of both electrical and mechanical (intrauterine pressure) activity. A combination of maxima- and level detection was used to define cycles in the intrauterine pressure signal, in which frequency, period time, area of the cycle, amplitude, overall- and maximum rate of rise were calculated. The electrical signal was assessed by calculating the root-mean-square (RMS) value in a moving time interval. A threshold value was applied to the obtained RMS curve to detect bursts of electrical activity present in the original signal. Burst frequency, burst period time and mean burst RMS value were calculated from the RMS curve. The algorithms were applied to recordings obtained from chronically instrumented ewes in various experiments.     

肠道压力数据的盒维数分形分析

结肠测压是广泛使用的评价消化道功能的检查手段,对结肠运动障碍疾病的诊断有较高的价值,是其他检查手段不可替代的。本研究对肠道压力数据进行分形特性的分析。首先对结肠压力数据进行预处理,采用截止频率为0.4Hz的低通滤波器滤除结肠压力信号中的高频干扰成分。采用盒维数计算正常受试者和异常受试者结肠压力数据的分形维数。计算盒维数的基本原理为利用待分析曲线的积分和差分的四分位偏差值来计算分形维数。结果表明,正常的结肠压力信号的分形维数值大且随时间的变化小而异常的结肠压力信号正好相反,采用分形维数可以作为判断肠道动力性能的辅助手段。     

Initial agonist burst duration changes with movement amplitude in a deafferented patient

Summary Changes in the duration of the initial agonist burst were studied in a deafferented human. The patient had been functionally deafferented for five years, having no touch, vibration, pressure or kinesthetic sensation nor any tendon reflexes in the four limbs. Pain and temperature sensation were intact and motor fibres were unaffected. The subject made visually guided step-tracking movements using flexion/extension movements about the elbow. Initial agonist burst duration increased with movement amplitude. Burst duration was approximately 65 ms in small movements (6–12 deg) increasing to 136 ms in intermediate (36 deg) and 200 ms in large (54 and 60 deg) movements. Similar changes in initial burst duration with movement amplitude were seen when the subject made non-visually guided movements. It is concluded that the duration of the initial agonist burst is centrally determined.This work was supported by the Medical Research Council of Canada and by a special grant from the Faculty of Medicine, University of Western Ontario     

可降解血管吻合器的结构设计与实验验证

目的 设计一种新型可降解血管吻合器,探究施压距离与吻合口生物力学性能之间的关系,以提高血管端端吻合的效率与质量。方法 设计吻合器的三维结构,并采用挤压态高纯镁为材料进行样机加工;通过建立血管端端吻合的有限元模型,研究在不同施压距离（0.4、0.5、0.6、0.7、0.8 mm）下,血管吻合端面应力分布情况及其变化规律;通过离体组织吻合实验,对有限元结果的合理性及该吻合器的可行性与有效性进行验证。结果 当施压距离为0.6 mm时,吻合口力学性能最优,此时撕脱力为(11.79±0.64) N,爆破压为(39.32±2.99) kPa,满足临床上对组织吻合口强度的要求,同时组织的力学损伤较小。结论 所设计的新型可降解血管吻合器可以通过调节施压距离对组织进行吻合,能够有效提高组织吻合效率,减小组织力学损伤,从而提高吻合质量。研究结果可以为可降解血管吻合器的设计提供重要参考。     

不同年龄段人群行走足底压力特征分析

目的获取不同年龄段人群正常行走时足底压力的动力学参数,为设计制作不同年龄段鞋垫和运动鞋提供理论依据,最大程度减小足部发生损伤的风险。方法使用Footscan测力平板对4个年龄段120名受试者(20～30、30～40、40～50、50～60岁男女各15名)足底压力峰值、压强峰值进行测试。结果足底压力峰值随着年龄增长不断变化,大部分呈上升趋势,只有在第1趾骨区域随着年龄的增长压力峰值逐渐减小,第1趾骨区域女性足底压力峰值在逐渐减小;大部分受试者第2、4拓骨头受力明显高于第1、5跖骨; 50～60岁年龄段男性第2跖骨压力峰值也明显大于20～50岁年龄段人群(P0. 05)。随着年龄增长,仅仅第1趾骨压力峰值逐渐减小,其余区域均呈现增长现象;压强峰值有显著变化,尤其以第2、3跖骨变化最大,呈上升趋势(P0. 05)。结论人体足底各分区的压力、压强随着年龄增长并非一成不变,找出每个年龄段人群足底压力特点,制定相应的运动鞋,才能更好发挥运动鞋的功能。     

The effect of carbon monoxide releasing molecule-2 (CORM-2) on healing of ischemic colon anastomosis in rats

Background/aimIschemia on the colon wall negatively affects healing of anastomosis. We were aimed to evaluate the effects of carbon monoxide releasing molecule-2 (CORM-2) on the healing of anastomosis in a rat model of the ischemic colon. Materials and methodsIn this prospective study a total of 60 rats were randomly divided into three groups as colon transection and end-to-end anastomosis (Group I), colon transection, and end-to-end anastomosis following the induction of ischemia (Group II), and colon transection and end-to-end anastomosis following the induction of ischemia and treated with daily intraperitoneal administration of CORM-2 (Group III). Each group was also divided into two equal subgroups as postoperative 3rd and 7th day. Postoperative healing of anastomoses was evaluated by anastomosis burst pressure (ABP), tissue biomarkers including hydroxyproline (HP), malondialdehyde (MDA), glutathione (GSH), and histopathological findings.ResultsIn the ischemic group treated with CORM-2, lower MDA and higher HP levels were observed in comparison to the untreated ischemic group on the 3rdday. GSH and HP levels were higher and MDA levels was lower in the ischemic rats treated with CORM-2 than in the ischemic untreated rats on the 7th day. In the ischemic group treated with CORM-2, the mucosal epithelial score decreased and the neoangiogenesis score increased compared to the untreated rats on the 7th day.ConclusionIn ischemic colon anastomosis, reduces cell destruction by suppressing the oxidative reaction, and strengthening the antioxidative mechanisms of the cells. It also increases collagen formation, epithelial development, and neoangiogenesis.     

Adrenomedulline improves ischemic left colonic anastomotic healing in an experimental rodent model

BACKGROUND:

Leakage from colonic anastomosis is a major complication causing increased mortality and morbidity. Ischemia is a well-known cause of this event. This study was designed to investigate the effects of adrenomedullin on the healing of ischemic colon anastomosis in a rat model.

METHODS

Standardized left colon resection 3 cm above the peritoneal reflection and colonic anastomosis were performed in 40 Wistar rats that were divided into four groups. To mimic ischemia, the mesocolon was ligated 2 cm from either side of the anastomosis in all of the groups. The control groups (1 and 2) received no further treatment. The experimental groups (3 and 4) received adrenomedullin treatment. Adrenomedullin therapy was started in the perioperative period in group 3 and 4 rats (the therapeutic groups). Group 1 and group 3 rats were sacrificed on postoperative day 3. Group 2 and group 4 rats were sacrificed on postoperative day 7. After careful relaparotomy, bursting pressure, hydroxyproline, malondialdehyde, interleukin 6, nitric oxide, vascular endothelial growth factor, and tumor necrosis factor alpha levels were measured. Histopathological characteristics of the anastomosis were analyzed.

RESULTS

The group 3 animals had a significantly higher bursting pressure than group 1 (p<0.05). Hydroxyproline levels in group 1 were significantly lower than in group 3 (p<0.05). The mean bursting pressure was significantly different between group 2 and group 4 (p<0.05). Hydroxyproline levels in groups 3 and 4 were significantly increased by adrenomedullin therapy relative to the control groups (p<0.05). When all groups were compared, malondialdehyde and nitric oxide were significantly lower in the control groups (p<0.05). When vascular endothelial growth factor levels were compared, no statistically significant difference between groups was observed. Interleukin 6 and tumor necrosis factor alpha were significantly decreased by adrenomedullin therapy (p<0.05). The healing parameters and inflammatory changes (e.g., granulocytic cell infiltration, necrosis, and exudate) were significantly different among all groups (p<0.05).

CONCLUSION

Adrenomedullin had positive effects on histopathologic anastomotic healing in this experimental model of ischemic colon anastomosis.     

新型可降解肠道吻合支架的建模仿真与实验研究

目的 设计一款新型可降解肠道吻合支架,探究肠道组织在加压吻合时施压距离与吻合口生物力学性能之间的关系,为肠道组织的加压吻合提供新思路与方法。方法 设计一款用于肠道组织的加压吻合支架,建立肠道组织加压吻合的有限元模型,并探究支架施压面距离（2、1.6、1.2、0.8 mm）与组织应力之间的关系;通过撕脱力与爆破压测试,分析肠道组织在不同施压距离下的吻合效果。结果 当施压距离为1.2 mm时,肠道吻合口的生物力学性能最佳,其最大抗拉强度达到0.77 MPa;组织的撕脱力和爆破压分别为(25.80±1.82) N和(12.30±0.26) kPa;当组织被压缩至原有厚度的60%时,肠道吻合效果最好。结论 本文设计的可降解肠道支架可成功实现对肠道组织的加压吻合,为新型可降解加压吻合器械的开发和应用提供理论参考。     

Colonic Motility in the Cat IV. Peripheral Pathways Mediating the Effects Induced by Hypothalamic and Mesencephalic Stimulation

Rostad , H. Colonic motility in the cat. IV. Peripheral pathways mediating the effects induced by hypothalamic and mesencephalic stimulation. Acta physiol. scand. 1973. 89. 154–168. The peripheral pathways by which the hypothalamus and mesencephalon influence the motility of the colon have been studied by combining brain stimulation and peripheral nerve sectioning, and by use of autonomic blocking agents. Excitatory colonic effects induced from the hypothalamic sympatho-inhibitory area with concomitant blood pressure falls were found to be mediated through the sympathetic lumbar colonic nerves, whereas excitatory responses with associated blood pressure rises were conveyed through the latter as well as through the parasympathetic pelvic nerves. On the other hand, the augmentatory colonic effects usually associated with blood pressure rise evoked from the mesencephalon were conveyed through the lumbar colonic nerves only. The responses through the lumbar colonic and pelvic nerves were blocked by guanethidine and atropine, respectively. The augmentatory colonic responses from the hypothalamic sympatho-inhibitory area were blocked by the beta-adrenergic blocking agent propranolol, whereas the effects from the other responsive hypothalamic areas, transmitted through the lumbar colonic nerves, were blocked by alpha-blocker (phenoxybenzaminc), but not by propranolol. This finding support the presence of alpha-excitatory receptors in the colonic wall. Inhibition of colonic motility induced by hypothalamic and mesencephalic stimulation, weir found to be mediated through the lumbar colonic as well as through the splanchnic nerves. The effects were blocked by guanethidine, and those from the responsive hypothalamic zones were also blocked by propranolol.     

Study of the functional activity of the cecocolonic junction with identification of a "physiologic sphincter", "cecocolonic inhibitory reflex" and "colocecal excitatory reflex"

Radiologic, endoscopic and histomorphologic studies have suggested the presence of a sphincter at the cecocolonic junction (CCJ), while some investigators have denied its existence. To investigate the physiologic activity at the CCJ, the right colon was exposed during right hemicolectomy for early colonic cancer in 11 patients (mean age 43.6+/-12.3 years; 8 men). Three manometric catheters were introduced through colotomy to be separately located in the cecum, CCJ and ascending colon. We determined the CCJ pressure response to cecal and colonic distension by means of a balloon filled with saline in increments of 10 ml. The test was repeated after individual anesthetization of cecum, CCJ and ascending colon. The CCJ measured 1.6+/-0.6 cm in length and had a higher pressure ( p<0.05) than the cecum or colon. Large-volume cecal distension effected a significant CCJ pressure reduction which was augmented as the distension increased. Latency decreased upon increase of the distending volume. In contrast, the CCJ responded to large-volume colonic distension by pressure elevation which increased upon increase of the distending volume. Latency diminished with increased distension. Small-volume cecal or colonic distension effected no CCJ pressure response. The anesthetized CCJ did not respond to distension of the cecum or colon. Likewise, the CCJ did not exhibit a pressure response to distension of the anesthetized cecum or colon. The CCJ is a high-pressure zone which reacts to cecal or colonic distension by dilatation or narrowing, respectively. These data presumably denote the existence of a physiologic sphincter at the CCJ. We suggest that the CCJ pressure response to cecal or colonic distension is reflex and mediated through the cecocolonic inhibitory and colocecal excitatory reflexes, respectively. The role of the CCJ and related reflexes in colonic motility disorders needs to be studied.