低强度脉冲超声与吡格列酮对骨关节炎软骨细胞的影响

目的 观察低强度脉冲超声(LIPUS)和吡格列酮(pioglitazone)经过氧化物酶增殖物激活受体γ(PPARγ)/核转录因子-κB（NF-κB）/诱导型一氧化氮合酶(iNOS)途径对骨关节炎(OA)软骨细胞的保护作用。 方法 选取健康成年新西兰大白兔24只,按随机数字表法分为正常组、脂多糖（LPS）组、LIPUS组(LPS+LIPUS)、吡格列酮组(LPS+吡格列酮),每组6只大白兔。分别提取4组大白兔膝正常软骨细胞,采用ELISA法检测4组软骨细胞肿瘤坏死因子-α(TNF-α)、瘦素（LEP）、一氧化氮(NO)的水平;采用免疫细胞化学和免疫荧光染色法检测4组软骨细胞Ⅱ型胶原(COL2)的表达情况;另采用实时荧光定量逆转录-聚合酶链反应(RT-PCR)和免疫蛋白印迹法检测(Western blot)技术分别检测4组软骨细胞的PPARγ,NF-κB,iNOS mRNA和蛋白表达水平。 结果 LIPUS组和吡格列酮组OA软骨细胞的TNF-α、LEP、NO水平与LPS组比较,均显著下降,差异均有统计学意义（P<0.05）,且吡格列酮组下调幅度大于LIPUS组,差异有统计学意义（P<0.05）;LIPUS组OA软骨细胞COL2的表达水平显著上调,与LPS组比较,差异有统计学意义（P<0.05）;LIPUS组和吡格列酮组OA软骨细胞PPARγ的mRNA和蛋白表达水平均高于LPS组,差异均有统计学意义（P<0.05）;吡格列酮组和LIPUS组OA软骨细胞NF-κB、iNOS mRNA和蛋白表达下降,与LPS组比较,差异均有统计学意义（P<0.05）,且吡格列酮组下降程度大于LIPUS组,差异有统计学意义（P<0.05）。 结论 LIPUS和吡格列酮均可能通过PPARγ/NF-κB/iNOS途径参与OA软骨细胞的抗炎症、COL2合成过程,起到OA软骨细胞的保护作用。     

The influence of pulsed low-intensity ultrasound on matrix production of chondrocytes at different stages of differentiation: an explant study

The proximal and distal parts of sterna of chick embryos represent cartilage undergoing endochondral ossification and hyaline cartilage, respectively. Cartilage explants from both regions were exposed for 20 min to pulsed low-intensity ultrasound (PLIUS) with an intensity of 30 mW. cm(-2) (spatial average-temporal average) at a frequency of 1.5 MHz, with a pulse burst frequency of 1 kHz and burst duration of 200 micros. Histological and immunohistochemical analysis was performed on days 1, 3, 5 and 7 after treatment. An anabolic effect of PLIUS on matrix production was shown by an increase of up to 10% to 20% in quantitative immunohistochemical staining for type II collagen and aggrecan in the two parts of the sternum. PLIUS also increased type X collagen staining by up to 10% in certain regions of the proximal part of the sternum. Staining for type X collagen was negative in the distal part of the sternum in both PLIUS and control groups. These results suggest that PLIUS may stimulate bone formation by increasing hypertrophy of chondrocytes directed to terminal differentiation. However, PLIUS did not induce hypertrophy in hyaline cartilage; moreover, increased matrix synthesis indicates a potential role in cartilage repair.     

Integrin-mediated mechanotransduction pathway of low-intensity continuous ultrasound in human chondrocytes

Chondrocytes are mechanosensitive cells that require mechanical stimulation for proper growth and function in in vitro culture systems. Ultrasound (US) has emerged as a technique to deliver mechanical stress; however, the intracellular signaling components of the mechanotransduction pathways that transmit the extracellular mechanical stimulus to gene regulatory mechanisms are not fully defined. We evaluated a possible integrin/mitogen-activated protein kinase (MAPK) mechanotransduction pathway using Western blotting with antibodies targeting specific phosphorylation sites on intracellular signaling proteins. US stimulation of chondrocytes induced phosphorylation of focal adhesion kinase (FAK), Src, p130 Crk-associated substrate (p130Cas), CrkII and extracellular-regulated kinase (Erk). Furthermore, pre-incubation with inhibitors of integrin receptors, Src and MAPK/Erk kinase (MEK) reduced US-induced Erk phosphorylation levels, indicating integrins and Src are upstream of Erk in an US-mediated mechanotransduction pathway. These findings suggest US signals through integrin receptors to the MAPK/Erk pathway via a mechanotransduction pathway involving FAK, Src, p130Cas and CrkII.     

Transforming growth factor-beta1 mediates the effects of low-intensity pulsed ultrasound in chondrocytes

Low-intensity pulsed ultrasound (LIPUS) has been shown to accelerate fracture healing, but the precise mechanism is still unknown. We used aggregate chondrocyte culture system to analyze LIPUS-induced effects on chondrocytes. First, Northern analyses revealed that LIPUS maintained higher expression levels of type II collagen and aggrecan mRNA and delayed the appearance of type X collagen mRNA expression. We also showed that DNA content was increased and that alkaline phosphatase activity was maintained low by daily treatment. Moreover, LIPUS significantly promoted transforming growth factor (TGF)-β₁ mRNA expression and the protein production at 2 h and 12 h after the treatment, respectively. Furthermore, recombinant TGF-β₁ protein mimicked the LIPUS effect and anti-TGF-β₁ neutralizing antibody reversed all these changes induced by the LIPUS treatment. These results indicate that LIPUS promotes the proliferation and retains the differentiation state of chondrocytes in the aggregate culture and that TGF-β₁ plays an important role in mediating the LIPUS effects in chondrocytes. (E-mail: smukai@kyotolan.hosp.go.jp)     

低强度脉冲超声治疗骨关节炎的应用进展

近年来低强度脉冲超声治疗骨关节炎在临床研究中取得了一定的疗效。研究内容涉及软骨细胞、Ⅱ型蛋白胶原、胶原酶、转化生长因子β、滑膜炎及病理改变等方面。系列临床研究结果说明低强度脉冲超声是一种无创伤、操作方便、费用低廉、疗效确切、并发症少的治疗方法。本文就低强度脉冲超声治疗骨关节炎的应用进展作一综述。     

The action of low-intensity pulsed ultrasound on amphibian embryonic tissues

Amphibian embryos at different stages of development, and ectomesodermal explants (small pieces of embryonic tissue extirpated from lateral parts of the embryos just after neurulation), have been irradiated with continuous and pulsed ultrasound at a frequency of 0.88 MHz, spatial and temporal average intensities being within the range 0.025–0.1 W cm⁻². Ultrasound pulse repetition frequencies were varied within 10–1000 Hz, duty factor being constant and equal to 0.5. Destruction of embryonic tussue as an immediate effect, and interruption or distortion of development as delayed (24 hr) effects, were registered.

Significant damaging effects of non-cavitational and non-thermal origin and dependent on pulse repetition frequencies, were observed. Highly frequency-dependent resonance-type effects were obtained for irradiated explants. The maximum effect on Rana temporaria explants was obtained at pulse repetition frequencies of 10–20 Hz and on Xenopus laevis explants at 110–130 Hz.     

The effect of low-intensity pulsed ultrasound on repair of epithelial cell monolayers in vitro

Low intensity pulsed ultrasound (LIPUS) is widely used to accelerate tissue regeneration following injury, but the biological mechanisms of this effect are poorly understood. An in vitro model of epithelial wound healing was used to investigate the effect of LIPUS on the reepithelialization of scrape wounds in normal human urothelial (NHU) cell monolayers. The effects of clinical doses of ultrasound treatment on NHU cell growth and migration were investigated in cells grown under optimal conditions, without growth supplements and in media containing low vs. physiological calcium concentrations. No differences in cell growth or migration were observed. We conclude that there is no direct effect upon uro-epithelial regeneration by therapeutic ultrasound in vitro and suggest that any stimulation of epithelial wound repair in vivo may occur indirectly, for example by modulating the extracellular matrix composition and/or production of paracrine factors by the stroma.     

低强度脉冲超声增强人外周血淋巴细胞增殖及抗癌活性的实验研究

目的探讨低强度脉冲超声(LIPUS)对人外周血淋巴细胞(HPBL)增殖和抗肿瘤效应的影响。方法采用Ficoll梯度离心法分离HPBL;将LIUPS强度0设为对照组,10 mW/cm^2组、20 mW/cm^2组、30 mW/cm^2组、40 mW/cm^2组、50 mW/cm^2组为刺激组刺激HPBL增殖,每天一次,每次刺激10 min,连续刺激2 d。CCK-8法检测各组细胞增殖活性;酶联免疫吸附法检测抗肿瘤因子[γ干扰素(INF-γ)、白介素2(IL-2)、肿瘤坏死因子α(TNF-α)、粒细胞-巨噬细胞集落刺激因子(GM-CSF)]表达情况;采用共培养HPBL与人肺巨细胞癌95D细胞检测其抗肿瘤活性。结果 LIPUS刺激HPBL2 d共2次后,30 mW/cm^2组的细胞增殖能力增强,与对照组和其他强度刺激组比较,细胞数量和细胞团块数量均增多。CCK-8检测结果显示,30 mW/cm^2组光密度值与对照组、20 mW/cm^2组、40 mW/cm^2组、50 mW/cm^2组比较差异均有统计学意义(P=0.032、0.027、0.027、0.001)。抗肿瘤因子检测显示,30 mW/cm^2组INF-γ、IL-2、TNF-α和GM-CSF分别为(39.66±8.30)ng/L、(619.84±125.94)ρg/ml、(461.29±14.08)ng/L、(108.11±2.07)ng/L,均高于对照组[(24.40±6.84)ng/L、(279.56±128.18)ρg/ml、(417.17±21.44)ng/L和(96.53±1.56)ng/L]和50 mW/cm^2组[(16.52±0.87)ng/L、(141.00±93.71)ρg/ml、(171.96±9.46)ng/L、(72.56±8.95)ng/L],差异均有统计学意义(均P<0.01)。共培养实验显示,30 mW/cm^2组人肺巨细胞癌95D细胞杀伤率为51.11%±5.21%,显著高于对照组(42.86%±0.55%)和50 mW/cm^2组(42.00%±3.67%),差异均有统计学意义(均P<0.05)。结论 LIPUS刺激可提高HPBL的增殖活性和杀伤率。     

Schlieren study of pulsed ultrasound transmission through human skull

A study has been made of the effects of the human skull on pulsed ultrasound from a diagnostic transducer. Schlieren photographs of ultrasound transmitted through a pediatric skull were made in various directions. Other than attenuation, little effect was observed on the directionality or spatial distribution of the ultrasonic pulses. These observations may be significant in considering the deleterious effects of the skull on imaging intracranial anatomy.     

低强度脉冲超声波对骨折愈合的影响

背景：随着人们寻求促进骨折愈合方法的同时,低强度脉冲超声波以其费用低廉、无创伤、无感染、治疗方便、无不良反应等优点逐步受到人们的关注与重视。目的：通过查阅大量相关资料并进行分析总结,从作用机制、动物实验和临床应用入手,对低强度脉冲超声波影响骨折愈合的研究现状进行综述,以期为促进骨折愈合提供新的思路和理论依据。方法：检索Pubmed数据库（http：//www.ncbi.nlm.gov/Pubmed）（1989/2009）、维普数据库（www.cqvip.com）（1981/2009）和万方数据库（www.wanfangdata.com.cn）（1981/2009）的相关文章。英文检索词为＂LIPUS,fracture＂,中文检索词为＂低强度脉冲超声波,骨折＂。纳入与低强度脉冲超声波或超声波治疗骨折密切相关,同一领域选择近期发表或在权威杂志上发表的文章;排除重复性文献。文献类型包括综述、动物试验和临床试验等。计算机初检得到60篇文献,根据入选标准保留35篇文献做进一步分析。结果与结论：低强度脉冲超声波治疗骨折具有费用低廉、安全、环保、无创性、无感染、操作简便、适用范围广和并发症少等优点,动物实验和临床应用等证实低强度脉冲超声波是一种有效的促进骨折愈合的方法,目前公认的是要应用低频率、低强度。低强度脉冲超声波治疗骨折,不仅涉及物理学,而且涉及医学等多个学科,由于对超声波方面研究进展,以及机体的复杂性及伦理方面问题,其作用机制以及脉冲超声波参数值及各参数间该如何组合还有待进一步探索。     

低强度脉冲超声波对骨折愈合的影响

背景:随着人们寻求促进骨折愈合方法的同时,低强度脉冲超声波以其费用低廉、无创伤、无感染、治疗方便、无不良反应等优点逐步受到人们的关注与重视.目的:通过查阅大量相关资料并进行分析总结,从作用机制、动物实验和临床应用入手,对低强度脉冲超声波影响骨折愈合的研究现状进行综述,以期为促进骨折愈合提供新的思路和理论依据.方法:检索Pubmed数据库(http://www.ncbi.nlm.gov/Pubmed)(1989/2009)、维普数据库(www.cqvip.com) (1981/2009)和万方数据库(www.wanfangdata.com.cn) (1981/2009)的相关文章.英文检索词为"LIPUS,fracture",中文检索词为"低强度脉冲超声波,骨折".纳入与低强度脉冲超声波或超声波治疗骨折密切相关,同一领域选择近期发表或在权威杂志上发表的文章;排除重复性文献.文献类型包括综述、动物试验和临床试验等.计算机初检得到60篇文献,根据入选标准保留35篇文献做进一步分析.结果与结论:低强度脉冲超声波治疗骨折具有费用低廉、安全、环保、无创性、无感染、操作简便、适用范围广和并发症少等优点,动物实验和临床应用等证实低强度脉冲超声波是一种有效的促进骨折愈合的方法,目前公认的是要应用低频率、低强度.低强度脉冲超声波治疗骨折,不仅涉及物理学,而且涉及医学等多个学科,由于对超声波方面研究进展,以及机体的复杂性及伦理方面问题,其作用机制以及脉冲超声波参数值及各参数间该如何组合还有待进一步探索.     

低强度脉冲超声促进C2C12成肌细胞分化的作用机制研究

目的观察不同功率密度低强度脉冲超声(LIPUS)对骨骼肌C2C12成肌细胞脂联素(Adiponectin)及其受体的影响,探讨LIPUS促进C2C12成肌细胞分化的潜在机制。方法将体外培养的C2C12成肌细胞根据有无超声干预或超声干预的功率密度随机分为对照组、U_0.1组、U_0.3组和U_0.5组,对照组接受假LIPUS干预,U_0.1组、U_0.3组、U_0.5组分别接受功率密度为0.1 W/cm²、0.3 W/cm²、0.5 W/cm²的LIPUS干预。干预5 d后,分别采用CCK-8法检测细胞活力,采用荧光定量逆转录-聚合酶链反应(RT-PCR)法检测脂联素、脂联素受体1(AdipoR1)和T-钙黏蛋白(T-Cadherin)mRNA水平,采用Western blot法检测脂联素、AdipoR1、T-Cadherin、腺苷酸活化蛋白激酶(AMPK)、活化型-磷酸化腺苷酸活化蛋白激酶(P-AMPK)、肌细胞生成蛋白(MYOG)和胚胎肌球蛋白重链(eMHC)的蛋白水平,并对4组细胞肌管的分化能力进行免疫荧光化学检测。结果LIPUS干预5 d后,U_0.1、U_0.3和U_0.5组细胞相对活力明显高于对照组(P<0.01)。U_0.3组和U_0.5组脂联素、受体AdipoR1和T-Cadherin mRNA水平均显著上调,与对照组比较,差异均有统计学意义(P<0.05)。U_0.3组和U_0.5组脂联素、AdipoR1、T-Cadherin蛋白和AMPK磷酸化水平与对照组比较,均显著增加(P<0.05),且U_0.1组和U_0.5组均显著低于U_0.3组,差异均有统计学意义(P<0.01)。U_0.3组和U_0.5组C2C12成肌细胞分化指标eMHC、MYOG蛋白水平和C2C12成肌细胞融合指数与对照组比较,均明显增加,差异均有统计学意义(P<0.05)。结论LIPUS可促进C2C12成肌细胞的分化,并以0.3 W/cm²、5 min/d、1 MHz,占空比为20%的LIPUS干预作用最明显,其调控机制可能与C2C12成肌细胞脂联素、受体AdipoR1和T-Cadherin的表达上调和下游AMPK磷酸化水平活化有关。     

低强度超声对离体大鼠膀胱平滑肌收缩的影响

目的 观察低强度脉冲超声(LIPUS)对离体大鼠膀胱平滑肌收缩的影响。方法 将32只SD雌性大鼠的32段离体膀胱肌条随机分为超声辐照组、超声辐照+尼莫地平组、超声辐照+低分子肝素组及对照组,每组各8段。采用BL-410F生物机能实验系统测量并记录超声辐照组、超声辐照+尼莫地平组、超声辐照+低分子肝素组在LIPUS辐照前、后的收缩曲线,并比较3组膀胱平滑肌条收缩频率、幅度。对超声辐照组LIPUS辐照后和对照组膀胱平滑肌进行组织病理学观察。结果 与LIPUS辐照前比较,辐照后超声辐照组的收缩频率和幅度均明显增加(P均<0.05),超声辐照+尼莫地平组的收缩频率和幅度均明显降低(P均<0.05),超声辐照+低分子肝素组的收缩频率和幅度均无明显变化(P均>0.05)。组织病理学显示超声辐照组膀胱平滑肌细胞与对照组比较无明显差异。结论 LIPUS辐照可激活膀胱平滑肌细胞膜L-型钙通道,继而引起膀胱平滑肌的收缩增强。     

Experience of an isolated use of low-intensity pulsed ultrasound therapy on fracture healing in established non-unions: a prospective case series

Fracture non-unions are responsible for approximately 5% of cases, with low expectation of spontaneous healing thereafter. The fractures that heal without complications can take months to heal completely. An ultrasound, typically at low intensities (0.5–50 mW/cm²), serves a diagnostic purpose, whereas at higher intensities (0.2–100 W/cm²), its role becomes more therapeutic by generating heat energy. Low-intensity pulsed ultrasound (LIPUS) is frequently used to stimulate or to accelerate fracture healing. We present a prospective review of fracture non-unions treated with low-intensity pulsed ultrasound (LIPUS). We enrolled 66 patients during August 2016 and December 2018, 38 males and 28 females; age range 19–85 years (average 49.2 years). All these patients were followed up to minimum 6 months. The average time of referral post-treatment for fractures was 8.2 months (range 6–18 months). Four patients were excluded due to various reasons. 39 out of 62 fractures showed successful healing with symptom improvement and callus formation with 67% success rate. In this case series, we noted LIPUS therapy failure in the post-ORIF scaphoid fracture and post-ankle joint fusion non-union. We did not observe any influence of a medical condition such as diabetes mellitus, osteoporosis or personal habits like smoking. The LIPUS therapy appears to have influence on bone healing, depending on the onset of therapy, fracture type and the approach to fracture care. In this case series, the compliant group showed 67% successful outcome.     

Skeletal effects of low-intensity pulsed ultrasound on the ovariectomized rodent

Growing evidence supports low-intensity pulsed ultrasound (US) as an osteogenic mechanical stimulus. Its effects on isolated bone cells and on fractured bone are established. However, its effects on osteoporosis are not clear. This study examined US effects on ovariectomy (OVX) induced bone changes within the rodent hindlimb (distal femur and proximal tibia), and on normal bone in animals following sham-OVX. Animals were exposed to daily unilateral active-US and contralateral inactive-US for 12 weeks. Bone status was assessed using dual energy X-ray absorptiometry and histomorphometry. Ovariectomy resulted in significant bone changes. Low-intensity pulsed US did not influence these changes. These results suggest that the US dose introduced may not be a beneficial treatment for osteoporosis, and that intact bone may be less sensitive to US than fractured bone and isolated bone cells. This may relate to the biophysical mechanisms of action of US, US-bone interactions and tissue level processes taking place.     

低强度脉冲超声波对兔膝骨性关节炎软骨整合素-FAK-MAPKs信号通路蛋白表达的影响

目的:观察低强度脉冲超声波(low-intensity pulsed ultrasound,LIPUS)对兔膝骨性关节炎(osteoarthritis,OA)软骨中整合素-FAK-MAPKs力化学细胞信号转导通路相关蛋白表达的影响。方法:18只成年新西兰大白兔随机平均分成3组,分为正常对照组(normal control,NC),OA模型组(OA group,OA),OA模型照射组(O+L)。OA组接受右侧后肢前交叉韧带切断(ACLT)处理术后4周接受LIPUS假辐射,O+L组同样手术处理,术后4周接受LIPUS辐射,NC组仅切开关节囊。LIPUS作用6周后,处死实验动物,取右后肢,采用HE染色行改良Mankin评分比较各组胫骨平台关节表面病理学改变。同时,采用Western blot技术检测Ⅱ型胶原,MMP-13,整合素β1的蛋白表达水平以及FAK、MAPKs家族蛋白(p38、ERK1/2、JNK)磷酸化水平。结果:1组织学观察及Mankin评分:LIPUS干预后,OA软骨表层轻微不平整,染色轻度缺失,可见软骨细胞增殖;Mankin评分,NC组:4.67±0.57;OA组:10.57±2.55;O+L组:7.66±1.74。与NC组相比,OA组、O+L组Mankin评分明显增高,但OA组增高更为明显(P0.05);与OA组相比,O+L组Mankin评分明显降低(P0.05)。2Ⅱ型胶原、MMP-13含量:LIPUS干预后,II型胶原含量较NC组升高,MMP-13含量有明显下降。3整合素β1-FAK-MAPKs信号通路相关蛋白表达:LIPUS干预使整合素β1、磷酸化FAK表达增高;同时MAPKs信号通路相关蛋白ERK1/2、p38磷酸化水平明显下降,而JNK磷酸化水平无明显变化。结论:LIPUS可以减轻骨性关节炎软骨ECM损伤程度,与LIPUS产生机械应力使关节软骨中细胞表面应力受体之一整合素β1及其下游分子黏着斑激酶FAK磷酸化表达增高,进一步下游的磷酸化p38,ERK1/2表达下调有关。LIPUS的机械效应可经力化学转导途径作用于OA关节软骨,为治疗骨性关节炎提供一种新的思路。     

聚焦式低强度脉冲超声治疗对大鼠坐骨神经损伤后神经病理性疼痛的影响

目的:观察聚焦式低强度脉冲超声(focused low-intensity pulsed ultrasound,FLIPUS)对坐骨神经损伤模型(spared nerve injury,SNI)大鼠的镇痛作用,以及对脊髓神经重塑的影响.方法:建立SNI神经病理性疼痛大鼠模型.将30只雄性SD大鼠随机分成3组,假手术组、...     

低强度脉冲超声增强人外周血淋巴细胞的增殖及抗癌活性

目的：本研究我们为了探讨低强度脉冲超声(LIPUS)对人外周血淋巴细胞(HPBL) 增殖和抗肿瘤效应的影响。方法：采用Ficoll梯度离心法分离HPBL;采用强度为0-80 mW/cm_²的LIUPS刺激HPBL增殖;CCK-8法检测细胞增殖活性;ELISA法检测抗肿瘤因子(γ干扰素(INF-γ)、白介素2(IL-2)、肿瘤坏死因子α(TNF-α)和粒细胞-巨噬细胞集落刺激因子(GM-CSF))在培养基上清中的表达;采用共培养HPBL与人肺巨细胞癌细胞(95D)检测其抗肿瘤活性。结果：与对照组(0 mW/cm_²)相比,LIPUS刺激组(30 mW/cm_²)每天刺激10 min,刺激2d后HPBL细胞增殖增强(P<0.01)。抗肿瘤因子刺激组INF-γ(39.66ng/L±8.30)、IL-2(619.84 pg/mL ± 125.94)、TNF-α(461.29 ng/L ± 14.08)和GM-CSF (108.11 ng/L ± 2.07),分别大于对照组(24.40ng/L±6.84)、(279.56 pg/mL ± 128.18)、(417.17 ng/ ± 21.44)和(96.53 ng/L ± 1.56);共培养实验显示,30 mW/cm_²组肺癌杀伤率为51.11%±5.21,对照组为42.86%±0.55。结论：LIPUS刺激后可提高HPBLs的增殖活性和杀伤率。本研究结果可能对LIPUS联合淋巴细胞治疗肿瘤具有较大的治疗潜力和依据。     

Biophysical effects of high-energy pulsed ultrasound on human cells

Human benign and malignant cells of different human origin (pancreas, liver, kidney, pharynx, tongue, lip) were exposed to high-energy pulsed ultrasound (HEPUS) in vitro to evaluate the effects of various physical parameters and sonication conditions on cell viability. This included the number of pulses, focal pressure, pulse repetition rate, pulse shape, cell suspension volume, water level of the basin and cell density. Cell viability was found to depend significantly on the number of pulses (exponential), the focal pressure (linear) and the pulse repetition rate (minimum at 1 Hz). Other parameters showed no marked influence. Furthermore, electron microscopy revealed intracellular damage, and proliferation rates of cells surviving sonication were normal after HEPUS exposure. The experimental piezoelectric ultrasound transducer used in the experiments generated oscillating bipolar pulses with high negative pressure amplitudes. Measurements were made of the pulse shape and ultrasonic field of the experimental device and of a conventional lithotripter for comparison.