肿胀法外超声吸脂术的组织学研究

目的 观察外超声能量作用于活体组织后的组织学变化，以探索其作用机制。方法 对3只家猪腹部两侧进行外超声与非超声比较，作用不同时间后在光镜和电镜下观察其皮肤组织全层的变化。结果 在外超声作用18min内，随着作用时间的延长，猪的皮下脂肪组织和生物大分子结构的破坏程度不断加重，脂肪组织中产生的空泡不断增大而皮肤组织及血管无明显变化。结论 外超声吸脂术可通过稳定的空泡效应选择性地使脂肪细胞结构发生不可逆的坏死性改变，这一改变与作用时间成正比。     

低频超声透皮给药的研究进展与应用

低频超声可以增强包括大分子药物在内的许多药物的透皮传输,其主要机制是超声的空化作用,大多数人认为是通过改变角质层角化细胞排列结构来提高皮肤渗透能力的.低频超声透皮给药已被人们用于离体实验和动物活体实验,到目前为止,无论是小分子透皮传输还是大分子透皮传输都有很多成功的例子.但是真正通过低频超声透皮导入药物进行治疗的临床应用报道很少,需要更进一步大量的临床试验以确定其安全性与实用价值.一旦其安全性得以证实,合适的低频超声透皮仪研制成功,低频超声快速透皮必将成为一种安全、有效、可控、经济的新型给药方式.     

GK型机械瓣空化可视化研究

对国产GK27型机械二尖瓣进行了单次关闭方式的离体空化实验，采用数码相机拍摄了空泡照片。机械瓣阻塞体关闭后，云状空泡出现在挡座周围，呈放射状向外运动，空化原因是机械瓣关闭时阻塞体与挡座的撞击形成的局部挤压射流，挤压缝隙出口射流速度高达9m/s，局部低压造成空化，在机理上，这是附壁射流引起的旋涡空化。关闭速度是衡量机械瓣空化趋势的重要指标之一。空化历时随心室载荷率的增加而增加，在载荷率为2750mmHg/s时，最大空化历时达440μs。机械瓣空化临界载荷率为420mmHg/s，这比动物实验所得的正常生理条件750mmHg/s低，因此在人体正常生理条件下，机械二尖瓣存在空化的可能。     

Cytotoxic and anti-proliferative effects of high-energy pulsed ultrasound (HEPUS) on human squamous cell carcinoma cells as compared to connective tissue fibroblasts

The cytotoxic and anti-proliferative effects of high-energy pulsed ultrasound (HEPUS) on human squamous cell carcinoma cells cloned from the hypopharynx (FaDu) and benign connective tissue cells (fibroblasts) were investigated in vitro. Sonication was carried out using an experimental piezoelectric, self-focusing burst-signal transducer. To increase the induction of cavitation, the transducer used was specifically designed to produce multiple oscillations with a high negative pressure amplitude. In both cell lines tested, the application of 100, 800 and 2000 pulses resulted in a high reduction of vital cells. After 2000 pulses, 4.0 ± 1.1% of the fibroblasts but only 2.0 ± 0.4% of the FaDu cells survived HEPUS exposure. A postexposure inhibiting effect of HEPUS for 10 days on the proliferation of surviving cells was noted for the FaDu cells exposed to 2000 pulses, but not as much for the fibroblasts. These findings support the hypothesis that human squamous cell carcinoma cells of the hypopharynx might be more sensitive to HEPUS than fibroblasts and that total tumor cell ablation might be possible in vitro given a sufficient number of HEPUS pulses. Received: 18 November 1997 / Accepted: 21 April 1998     

Effects of Extracorporeal Shock Wave-Mediated Transdermal Local Anesthetic Drug Delivery on Rat Caudal Nerves

Cavitation plays a substantial role in the clinical effects of extracorporeal shock wave therapy (ESWT). It is also generally accepted as a major mechanism in sonophoresis. To identify the enhancing effect of extracorporeal shock wave-mediated transdermal drug delivery, 24 Wistar rats were randomly assigned to four groups: (i) topical application of a eutectic mixture of local anesthetics (EMLA); (ii) 1-MHz ultrasound; (iii) ESWT pre-treatment combined with EMLA application; (iv) ESWT concurrent with EMLA application on rat tails. The degree of anesthesia was assessed using the amplitude and latency of sensory nerve action potentials within 5?min after a 60-min EMLA application. The results indicated that ESWT pre-treatment and concurrent ESWT accelerated the anesthetic effects of the EMLA cream on the tail nerve (p?<?0.05). This finding might indicate that shock wave-mediated transdermal drug delivery is possible during the ESWT period.     

Experimental Methods for Improved Spatial Control of Thermal Lesions in Magnetic Resonance-Guided Focused Ultrasound Ablation

Magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU, or MRgFUS) is a hybrid technology that was developed to provide efficient and tolerable thermal ablation of targeted tumors or other pathologic tissues, while preserving the normal surrounding structures. Fast 3-D ablation strategies are feasible with the newly available phased-array HIFU transducers. However, unlike fixed heating sources for interstitial ablation (radiofrequency electrode, microwave applicator, infra-red laser applicator), HIFU uses propagating waves. Therefore, the main challenge is to avoid thermo-acoustical adverse effects, such as energy deposition at reflecting interfaces and thermal drift of the focal lesion toward the near field. We report here our investigations on some novel experimental solutions to solve, or at least to alleviate, these generally known tolerability problems in HIFU-based therapy. Online multiplanar MR thermometry was the main investigational tool extensively used in this study to identify the problems and to assess the efficacy of the tested solutions. We present an improved method to cancel the beam reflection at the exit window (i.e., tissue-to-air interface) by creating a multilayer protection, to dissipate the residual HIFU beam by bulk scattering. This study evaluates selective de-activation of transducer elements to reduce the collateral heating at bone surfaces in the far field, mainly during automatically controlled volumetric ablation. We also explore, using hybrid US/MR simultaneous imaging, the feasibility of using disruptive boiling at the focus, both as a far-field self-shielding technique and as an enhanced ablation strategy (i.e., boiling core controlled HIFU ablation).     

高声压脉冲超声空化作用对兔肝细胞水通道蛋白4及钠钾ATP酶表达的影响作用研究

目的：结合前期微泡增强的高声压脉冲超声空化作用致兔肝血流灌注降低的研究结果,进一步探讨高声压超声辐照对兔肝细胞水通道蛋白4（Aquaporin 4, AQP 4）及钠钾ATP酶（Na+-K+ ATPase）表达的影响作用,通过检测不同辐照时间作用后AQP 4及Na+-K+ ATPase蛋白表达量的改变,从而探究水分子转运相关蛋白表达与肝细胞肿胀之间的关系。方法：健康新西兰大白兔41只,随机分入空白对照组（n=5）及不同辐照时间组：T1组（辐照时间1 min,n=12）、T5组（辐照时间5 min,n=12）及T10组（辐照时间10 min,n=12）。T1、T5及T10组动物采用高峰值负压（P=2.0 MPa）超声脉冲联合经静脉脂质微泡注射进行肝脏超声空化辐照处理,超声辐照后获取肝脏组织标本;空白对照组动物仅行开腹手术获取肝脏组织标本。免疫组织化学法观察各组AQP 4及Na+-K+ ATPase蛋白表达分布情况,蛋白免疫印迹法（WB）检测各组AQP 4及Na+-K+ ATPase蛋白表达量。结果：超声辐照治疗后各治疗组AQP 4及Na+-K+ ATPase强阳性表达细胞较空白对照组数量增多、分布范围广泛;T1、T5及T10组AQP 4蛋白表达量较对照组均显著增高,差异有统计学意义（P＜0.05）,组间比较提示T1、T10组与T5组AQP 4蛋白表达量差异均有统计学意义（P＜0.05）,而T1组和T10组之间AQP 4蛋白表达量差异无统计学意义（P＞0.05）;T5组及T10组Na+-K+ ATPase蛋白表达量明显高于空白对照组及T1组,差异均有统计学意义（P＜0.05）,两组之间比较其差异亦有统计学意义（P＜0.05）,而T1组与空白对照组比较差异没有统计学意义（P＞0.05）。 结论：高声压脉冲超声空化作用在引起正常兔肝组织水肿的同时可引起AQP 4及Na+-K+ ATPase蛋白表达量的增加,超声辐照时间的长短对蛋白表达量的增加有影响。     

新型超声诊疗一体机VINNO70的空化调控功能及声学测量

目的 对新型超声诊疗一体机VINNO 70的空化调控功能,以及对超声频率、脉冲宽度、脉冲重复频率及机械指数等声学参数进行测量,以及VFlash超声治疗模式下的声场分布及自适应可变焦域技术。方法 利用薄膜水听器法测量各项参数的实测值,验证其与仪器显示值的一致性。其中,重点测量在距换能器表面2cm和5cm位置感兴趣区（ROI）内的峰值负压值,然后计算对应的机械指数（MI）,并与MI仪器显示值对比。结果 超声线阵探头X4-12L与凸阵探头S1-8C在超声频率、脉冲宽度、脉冲重复频率参数的实测值与仪器显示值完全一致。峰值负压值的声场分布显示,自适应可变焦域区具有明显的超声弱聚焦性能,ROI内微泡击破明显。但是MI实测值与仪器显示值有较大差距（58%-267%）,而且频率与测量距离等均可以影响MI值。结论 VINNO 70超声仪准确调控多个空化相关参数,自适应可变焦域技术可以明显靶向击破ROI区内的微泡。MI实测值与显示值差别较大,因此,实施治疗时应该以实测值为准。     

高声压脉冲超声空化作用对兔肝细胞水通道蛋白4及钠钾ATP酶表达的影响

目的 探讨高声压脉冲超声空化作用对兔肝细胞水通道蛋白4(AQP 4)及钠钾ATP酶(Na+-K+ATPase)表达的影响.方法 将健康新西兰大白兔41只随机分为空白对照组(n=5)及不同辐照时间组:T1组(辐照时间1 min,n=12)、T5组(辐照时间5 min,n=12)及T10组(辐照时间10 min,n=12)...     

低频超声辐射微泡造影剂对人乳腺癌细胞的生物学效应研究

目的观察微泡造影剂不同浓度、不同声学参数对体外培养人乳腺癌细胞的生物学效应。方法人乳腺癌细胞株MDA-MB-231,受不同剂量,频率为300kHz的超声波辐照破坏微泡声学造影剂,采用噻唑蓝(MTT)法检测细胞存活率。结果在微泡浓度为5%时,0.25W/cm2×10s与0.5W/cm2×5s组细胞存活率未见明显改变,而0.5W/cm2×10s、0.5W/cm2×20s、0.5W/cm2×40s、1.0W/cm2×10s、2.0W/cm2×10s各组与对照组比较,细胞存活率明显下降。辐照强度为0.5W/cm2、照射时间10s时,随着微泡浓度增加,超声对细胞的杀伤效应越强,与对照组相比,5%微泡浓度组P<0.05,其余各组P<0.01。结论超声破坏微泡声学造影剂对人乳腺癌细胞的杀伤程度与超声辐照时间、声强及微泡浓度有关。