Low-intensity pulsed ultrasound reduces alveolar bone resorption during orthodontic treatment via Lamin A/C-Yes-associated protein axis in stem cells

BACKGROUND The bone remodeling during orthodontic treatment for malocclusion often requires a long duration of around two to three years,which also may lead to some complications such as alveolar bone resorption or tooth root resorption.Low-intensity pulsed ultrasound(LIPUS),a noninvasive physical therapy,has been shown to promote bone fracture healing.It is also reported that LIPUS could reduce the duration of orthodontic treatment;however,how LIPUS regulates the bone metabolism during the orthodontic treatment process is still unclear.AIM To investigate the effects of LIPUS on bone remodeling in an orthodontic tooth movement(OTM)model and explore the underlying mechanisms.METHODS A rat model of OTM was established,and alveolar bone remodeling and tooth movement rate were evaluated via micro-computed tomography and staining of tissue sections.In vitro,human bone marrow mesenchymal stem cells(hBMSCs)were isolated to detect their osteogenic differentiation potential under compression and LIPUS stimulation by quantitative reverse transcription-polymerase chain reaction,Western blot,alkaline phosphatase(ALP)staining,and Alizarin red staining.The expression of Yes-associated protein(YAP1),the actin cytoskeleton,and the Lamin A/C nucleoskeleton were detected with or without YAP1 small interfering RNA(siRNA)application via immunofluorescence.RESULTS The force treatment inhibited the osteogenic differentiation potential of hBMSCs;moreover,the expression of osteogenesis markers,such as type 1 collagen(COL1),runt-related transcription factor 2,ALP,and osteocalcin(OCN),decreased.LIPUS could rescue the osteogenic differentiation of hBMSCs with increased expression of osteogenic marker inhibited by force.Mechanically,the expression of LaminA/C,F-actin,and YAP1 was downregulated after force treatment,which could be rescued by LIPUS.Moreover,the osteogenic differentiation of hBMSCs increased by LIPUS could be attenuated by YAP siRNA treatment.Consistently,LIPUS increased alveolar bone density and decreased vertical bone absorption in vivo.The decreased expression of COL1,OCN,and YAP1 on the compression side of the alveolar bone was partially rescued by LIPUS.CONCLUSION LIPUS can accelerate tooth movement and reduce alveolar bone resorption by modulating the cytoskeleton-Lamin A/C-YAP axis,which may be a promising strategy to reduce the orthodontic treatment process.

The Effect of Material Surface Microstructure on the Enhancement of Bone-Bonding Ability of a Hydroxyapatite-Implant by Low-Intensity Pulsed Ultrasound (LIPUS)

Excellent firm bonding between the biomaterials and bone tissue (osseointegration and osteo-conductivity) has been desired for the stability in vivo of dental implants and artificial joints. Much has been learned about this concept, which has led to significant improvements in the design and surface modification of implants in the field of implant dentistry, orthopedic surgery. We have already reported that low-intensity pulsed ultrasound (LIPUS) irradiation can accelerate the bone bonding ability of the bio-conductive materials such as bioactive titanium and hydroxyapatite implant. However, it is still unclear whether the LIPUS could have same effect to different types of the bioactive-materials. Therefore, in this study, the differences of bone-like hydroxyapatite formation on some kind of hydroxyapatite surface in simulated body fluid (SBF) under the LIPUS irradiation were investigated. Two kinds of hydroxyapatite samples immersed in SBF was exposed to ultrasound waves, the bone-like apatite on the surface was analyzed by Scanning electron microscopy and X-ray diffraction. As a result, the enhancement of hydroxyapatite formation on the surface by LIPUS was confirmed, the initial epitaxial nucleation and crystal growth of apatite depended on crystal structure of the surface of matrix materials.

Effect of Low-Intensity Pulsed Ultrasound on Ischaemic Heart Disease Patients (Novel Technique)

Ischaemic Heart Disease (IHD) or Coronary heart disease means that the heart is not getting enough blood and oxygen supply through the coronary arteries. The most common cause of this disease is the process of atherosclerosis in the coronary arteries. Although significant progress has been made in the management of ischaemic heart disease (IHD) The number of severe IHD patients is increasing. The treatment options for IHD have not changed much over the last three decades, which is divided between medications, coronary Angioplasty and Coronary artery bypass surgery. Thus it was crucial to develop new, non-invasive therapeutic strategies in case of Failure of medical or interventional therapy or in case patient is not fit for surgery or angioplasty. In this study, we are pleased to reveal a novel technique that was carried out on a human model. We aimed to develop low-intensity pulsed ultrasound (LIPUS) therapy for the treatment of patients with Ischaemic Heart Disease. We have set up the inclusion and exclusion criteria, the treatment protocol of LIPUS on IHD patients. In this limited group of IHD patients, We found promising clinical results and improvement on myocardial functions.

Effect of low-intensity pulsed ultrasound on posterolateral lumbar fusion of rabbit

Objective:To observe the effect of low-intensity pulsed ultrasound in the posterolateral Lumbar fusion of rabbit.Methods:A total of 48 New Zealand white rabbits were randomly divided into the observation group and control group,including the autogenous iliac observation group.artificial bone observation group,artificial bone control group and autogenous iliac control group according to the different bone grafting.The posterolateral lumbar fusion of rabbits in each group was analyzed and compared.Results:After 4 weeks of treatment using the low-intensity pulsed ultrasound,the fusion in the bone grafting area of observation group was good.There was the relatively dense fusion area between the right transverse process and artificial bone.The left transverse process had been completely fused,with the clear bone trabecula through the fusion area.There was no significant fusion sign in the control group.According to the fusion comparison between two groups,the fusion rale of the observation group was 83.3%and it was significantly higher than the one of the control group(37.5%).Results of the comparison were statistically significant(P<0.05).The number of chondrocytes and the increase in the relative gray-scale in the fusion area of the iliac observation group were significantly higher than ones of the iliac control group(P<0.05).The number of chondrocytes and the increase in the relative gray-scale in the fusion area of the artificial bone observation group were significantly higher than ones of the artificial bone control group(P<0.05).The expression of IL-1.IL-6 and IL-17 4 weeks after the treatment of the observation group was significantly lower than the one of the control group,with the statistical significance(P<0.05).It indicated that the treatment of low-intensity pulsed ultrasound could reduce the expression level of inflammatory factors.Conclusions:The low-intensity pulsed ultrasound can significantly increase the bone grafting fusion rate of the rabbit's posterolateral lumbar fusion.The possible mechanism is that it promotes the lumbar posterolateral endochondral ossification and reduces the inflammatory reaction.

Effects of low-intensity pulsed ultrasound stimulation on porous hydroxyapatite blocks for posterolateral fusion of lumbar spine in rabbits

The effects of porous hydroxyapatite blocks(PHABs) and an adjunct low-intensity pulsed ultrasound stimulation(LIPUS) on the fusion rate in a rabbit spinal posterolateral fusion(PLF) model were evaluated.Twenty rabbits underwent PLF with autograft and PHABs were randomly assigned to two groups:treated group with 20 min LIPUS daily and untreated control group for 4 weeks until euthanasia.The fused motion segments were subjected to manual palpation,gross observation,and radiographic investigation before histomorphologic and scanning electron microscopic analyses.Statistical differences between the LIPUS group and the control group are found in the fusion rate,bone density gray scale,trabecular bone formation,osteoblast-like cells,chondrocytes and positive expression of BMP-2 and TGF-β1 in the junction zone(significance level p<0.05).The results suggest that LIPUS can increase fusion rates and accelerate bone in-growth into PHAB.Hence,PHAB and LIPUS may be used together to increase fusion rates in a rabbit spinal fusion model with a promising extension to human application.

Extracellular vesicles derived from human dental mesenchymal stem cells stimulated with low-intensity pulsed ultrasound alleviate inflammation-induced bone loss in a mouse model of periodontitis

Extracellular vesicles(EVs)derived from mesenchymal stem cells(MSCs)have emerged as a new mode of intercellular crosstalk and are responsible for many of the thera-peutic effects of MSCs.To promote the application of MSC-EVs,recent studies have focused on the manipulation of MSCs to improve the production of EVs and EV-mediated activities.The current paper details an optimization method using non-invasive low-intensity pulsed ul-trasound(LIPUS)as the stimulation for improving oral MSC-EV production and effectiveness.Stem cells from apical papilla(SCAP),a type of oral mesenchymal stem cell,displayed inten-sity-dependent pro-osteogenic and anti-inflammatory responses to LIPUS without significant cytotoxicity or apoptosis.The stimuli increased the secretion of EVs by promoting the expres-sion of neutral sphingomyelinases in SCAP.In addition,EVs from LIPUS-induced SCAP exhibited stronger efficacy in promoting the osteogenic differentiation and anti-inflammation of peri-odontal ligament cells in vitro and alleviating oral inflammatory bone loss in vivo.In addition,LIPUS stimulation affected the physical characteristics and miRNA cargo of SCAP-EVs.Further investigations indicated that miR-935 is an important mediator of the pro-osteogenic and anti-inflammatory capabilities of LIPUS-induced SCAP-EVs.Taken together,these findings demonstrate that LIPUS is a simple and effective physical method to optimize SCAP-EV produc-tion and efficacy.

Low-intensity pulsed ultrasound for regenerating peripheral nerves:potential for penile nerve

Peripheral nerve damage,such as that found after surgery or trauma,is a substantial clinical challenge.Much research continues in attempts to improve outcomes after peripheral nerve damage and to promote nerve repair after injury.In recent years,low-intensity pulsed ultrasound(LIPUS)has been studied as a potential method of stimulating peripheral nerve regeneration.In this review,the physiology of peripheral nerve regeneration is reviewed,and the experiments employing LIPUS to improve peripheral nerve regeneration are discussed.Application of LIPUS following nerve surgery may promote nerve regeneration and improve functional outcomes through a variety of proposed mechanisms.These include an increase of neurotrophic factors,Schwann cell(SC)activation,cellular signaling activations,and induction of mitosis.We searched PubMed for articles related to these topics in both in vitro and in vivo animal research models.We found numerous studies,suggesting that LIPUS following nerve surgery promotes nerve regeneration and improves functional outcomes.Based on these findings,LIPUS could be a novel and valuable treatment for nerve injury-induced erectile dysfunction.

Improved activity of MC3T3-E1 cells by the exciting piezoelectric BaTiO_(3)/TC4 using low-intensity pulsed ultrasound

Developing bioactive materials for bone implants to enhance bone healing and bone growth has for years been the focus of clinical research.Barium titanate(BT)is an electroactive material that can generate electrical signals in response to applied mechanical forces.In this study,a BT piezoelectric ceramic coating was synthesized on the surface of a TC4 titanium alloy,forming a BT/TC4 material,and low-intensity pulsed ultrasound(LIPUS)was then applied as a mechanical stimulus.The combined effects on the biological responses of MC3T3-E1 cells were investigated.Results of scanning electron microscopy,energy-dispersive X-ray spectroscopy,and X-ray diffraction showed that an uniform nanospheres-shaped BT coating was formed on TC4 substrate.Piezoelectric behaviors were observed using piezoelectric force microscopy with the piezoelectric coefficient d_(33)of 0.42 pC/N.Electrochemical measures indicated that LIPUS-stimulated BT/TC4 materials could produce a microcurrent of approximately 10μA/cm^(2).In vitro,the greatest osteogenesis(cell adhesion,proliferation,and osteogenic differentiation)was found in MC3T3-E1 cells when BT/TC4 was stimulated using LIPUS.Furthermore,the intracellular calcium ion concentration increased in these cells,possibly because opening of the L-type calcium ion channels was promoted and expression of the Ca_(V)1.2 protein was increased.Therefore,the piezoelectric BT/TC4 material with LIPUS loading synergistically promoted osteogenesis,rending it a potential treatment for early stage formation of reliable bone-implant contact.

Low-intensity pulsed ultrasound stimulates proliferation of stem/progenitor cells: what we need to know to translate basic science research into clinical applications

Low-intensity pulsed ultrasound (LIPUS) is a promising therapy that has been increasingly explored in basic research and clinical applications. LIPUS is an appealing therapeutic option as it is a noninvasive treatment that has many advantages, including no risk of infection or tissue damage and no known adverse reactions. LIPUS has been shown to have many benefits including promotion of tissue healing, angiogenesis, and tissue regeneration;inhibition of inflammation and pain relief;and stimulation of cell proliferation and differentiation. The biophysical mechanisms of LIPUS remain unclear and the studies are ongoing. In recent years, more and more research has focused on the relationship between LIPUS and stem/progenitor cells. A comprehensive search of the PubMed and Embase databases to July 2020 was performed. LIPUS has many effects on stem cells. Studies show that LIPUS can stimulate stem cells in vitro;promote stem cell proliferation, differentiation, and migration;maintain stem cell activity;alleviate the problems of insufficient seed cell source, differentiation, and maturation;and circumvent the low efficiency of stem cell transplantation. The mechanisms involved in the effects of LIPUS are not fully understood, but the effects demonstrated in studies thus far have been favorable. Much additional research is needed before LIPUS can progress from basic science research to large-scale clinical dissemination and application.

Low-intensity pulsed ultrasound prompts tissue-engineered bone formation after implantation surgery

Background A practical problem impeding clinical translation is the limited bone formation seen in artificial bone grafts.Low-pressure/vacuum seeding and dynamic culturing in bioreactors have led to a greater penetration into the scaffolds,enhanced production of bone marrow cells,and improved tissue-engineered bone formation.The goal of this study was to promote more extensive bone formation in the composites of porous ceramics and bone marrow stromal cells （BMSCs）.Methods BMSCs/β-tricalcium phosphate （β-TCP） composites were subcultured for 2 weeks and then subcutaneously implanted into syngeneic rats that were split into a low-intensity pulsed ultrasound （LIPUS） treatment group and a control group.These implants were harvested at 5,10,25,and 50 days after implantation.The samples were then biomechanically tested and analyzed for alkaline phosphate （ALP） activity and osteocalcin （OCN） content and were also observed by light microscopy.Results The levels of ALP activity and OCN content in the composites were significantly higher in the LIPUS group than in the control group.Histomorphometric analysis revealed a greater degree of soft tissue repair,increased blood flow,better angiogenesis,and more extensive bone formation in the LIPUS groups than in the controls.No significant difference in the compressive strength was found between the two groups.Conclusion LIPUS treatment appears to enhance bone formation and angiogenesis in the BMSCs/β3-TCP composites.

Low-Intensity Pulsed Ultrasound Promote Schwann Cells Pro-Myelination Activities and Neurite Outgrowth of Dorsal Root Ganglion Neurons

In this study,we investigate how Schwann cells and dorsal root ganglion(DRG)neurons response to direct low-intensity pulsed ultrasound(LIPUS)stimuli in vitro.Primary Schwann cells and DRG were isolated from rat sciatic nerve and spine,respectively.LIPUS with varied dose of intensity(low:250 mW/cm2,medium:500 m W/cm2,high:750 m W/cm2)were applied 5 min per time for every other day,and pro-myelination indicators of Schwann cell as well as neurite outgrowth of dorsal root ganglion neurons were analyzed.Our results demonstrated that LIPUS promoted Schwann cells activity and proliferation from day 3 at the highest intensity,and day 5 at all intensities.In addition,LIPUS boosted pro-myelination activities of Schwann cells,as evidenced by increased cell population that positive for immunohistochemical staining against S100,nerve growth factor receptor(NGFR)p75,glial fibrillary acidic protein(GFAP),myelin protein zero(P0),as well as up-regulation of GFAP,Protein 0,nerve growth factor(NGF),and brain derived neurotrophic factor(BDNF)genes.Furthermore,LIPUS significantly enhanced the neurite outgrowth of DRG,with the highest intensity exhibiting longest neurite outgrowth.Taken together,our results strongly improve the understanding of cellular mechanisms of ultrasonic therapies for peripheral nerve repair.

Effects of low-intensity pulsed ultrasound in repairing injured articular cartilage

Objective: To investigate the effects of low-intensity pulsed ultrasound in repairing injured articular cartilage. Methods: Ten adult New Zealand rabbits with bilateral full-thickness osteochondral defects on the cartilage surface of intercondylar fossas were used in this study. The wounds in the left knees were treated with low-intensity pulsed ultrasound as the experimental group. The right knees received no treatment as the control group. All the animals were killed at 8 weeks after injury and the tissues in the wounds were collected for gross appearance grading, histological grading and proteoglycan quantity. Results: The scores of the gross appearance grades, histological grades and the optical density of toluidine blue of the tissues in the experimental group were significantly higher than those of the controls at 8 weeks after injury (P<(0.05)). Conclusions: Low-intensity pulsed ultrasound can accelerate the repair of injured articular cartilage.

Low-intensity pulsed ultrasound therapy: a potential strategy to stimulate tendon-bone junction healing

Incorporation of a tendon graft within the bone tunnel represents a challenging clinical problem. Successfulanterior cruciate ligament (ACL) reconstruction requires solid healing of the tendon graft in the bone tunnel. En-hancement of graft healing to bone is important to facilitate early aggressive rehabilitation and a rapid return topre-injury activity levels. No convenient, effective or inexpensive procedures exist to enhance tendon-bone (T-B)healing after surgery. Low-intensity pulsed ultrasound (LIPUS) improves local blood perfusion and angiogenesis,stimulates cartilage maturation, enhances differentiation and proliferation of osteoblasts, and motivates osteogenic differentiation of mesenchymal stem cells (MSCs), and therefore, appears to be a potential non-invasive tool for T-Bhealing in early stage of rehabilitation of ACL reconstruction. It is conceivable that LIPUS could be used to stimulateT-B tunnel healing in the home, with the aim of accelerating rehabilitation and an earlier return to normal activities inthe near future. The purpose of this review is to demonstrate how LIPUS stimulates T-B healing at the cellular andmolecular levels, describe studies in animal models, and provide a future direction for research.

Wideband frequency-dependent dielectric properties of rat tissues exposed to low-intensity focused ultrasound in the microwave frequency range

Tissue dielectric properties can vary upon the incident of an acoustic wave.The goal of this study is to quantify this change due to the acoustoelectric effect(AE),and to obtain the frequency-dependent dielectric properties of tissues exposed to low-intensity focused ultrasound(LIFU).The dielectric properties of the blood,brain,chest muscle,heart,kidney,leg muscle,liver,lung,pancreas,and spleen of rats were measured by an open-ended coaxial probe method.The acoustic intensity of LIFU focus was 2.97 MPa(67.6 W/cm^(2)),3.95 MPa(120 W/cm^(2)),and 5.17 MPa(204 W/cm^(2)),respectively,and the measurement frequency band was 0.1–7.08 GHz.The measurement results show that with the LIFU modulation,the conductivity and dielectric constant decreased in the high-frequency band,and on the contrary,they increased in the lowfrequency band,and the larger the acoustic intensity was,the more obvious the phenomenon was.This work contributes to a better understanding of the mechanisms by which ultrasound acts on the dielectric properties of biological tissues.It is expected that the findings from this study will provide a basis that the response of tissue to LIFU modulation can be monitored by noninvasive techniques such as microwave-induced thermoacoustic imaging(MTI)and microwave imaging,present a new idea for improving the endogenous contrast between different biological tissues in MTI and acoustoelectric imaging,and possibly lead to the development of a new imaging method based on the relaxation time of tissue after LIFU modulation.

Effect of low intensity pulsed ultrasound on expression of TIMP-2 in serum and expression of mmp-13 in articular cartilage of rabbits with knee osteoarthritis

Objective:To study the effect of low intensity pulsed ultrasound(LIPUS) on the expression of tissue inhibitor of metalloproteinase-2(TIMP-2) in the serum and expression of matrix metallopeptidase 13(MMP-13) in the articular cartilage cells of rabbits with knee osteoarthritis(OA).Methods:Inner patellar ligament defect method was used to establish the model of knee OA.Four weeks after the modeling,the arterial blood was drawn from the ear of each rabbit,while ELISA was employed to detect the expression of TIMP-2 in the serum.The chondrocytes were separated from animals in each group and then cultured in vitro.All rabbits were divided into control group,OA model group and OA + LIPUS group.Cells in the control and OA groups were not treated,while cells in the OA+ LIPUS group were treated with LIPUS(40 mW/cnr.1 time/day).Cells were collected 7 d later and the RNA and total protein were extracted respectively.Real-time PCR and Western blotting were employed to analyze the expression of MMP-13 in chondrocytes at the mRNA and protein level,respectively.Results:The success rate of establishment of OA model was 83%.The results of ELISA showed that the content of TIMP-2 in the serum of animals with OA was 22.3%,lower than the one in the control group(P<0.05).Compared with the normal control group,the expression of TIMP-2in the OA model group was significantly increased,while the expression of MMP-13 was significantly increased(P<0.05).After the stimulation of LIPUS,the expression of TIMP-2 and MMP-13 was close to the one in the normal control group.Conclusions:The inner patellar ligament defect method is a mature method to establish the rabbit OA model,with high success rate.The expression of serum TIMP-2 in the OA model group is significantly decreased.LIPUS can up-regulate TIMP-2 and down-regulate MMP-13.

Osteogenic Effect of Low Intensity Pulsed Ultrasound on Rat Adipose-derived Stem Cells in vitro

The osteogenic in vitro effect of low intensity pulsed ultrasound (LIPUS) on SD rat adi-pose-derived stem cells (ADSCs) was investigated.Rat ADSCs underwent LIPUS (intensity=100 mW/cm2) or sham exposure for 8 min per treatment once everyday in vitro,and then the alkaline phos-phatase (ALP) activity and mineralized nodule formation were assessed to evaluate the osteogenic effect of LIPUS on ADSCs.To further explore the underlying mechanism,the osteogenic-related gene mRNA expression was determined by using reverse transcriptase-polymerase chain reaction (RT-PCR) at 1st,3rd,5th,7th day after exposure repectively.Westen blot was used to evaluate the protein expression levels of two osteogenic differentiation associated genes at 7th and 14th day repectively.It was found that ALP activity was increased after LIPUS exposure and LIPUS resulted in mineralized nodule formation of ADSCs in vitro.LIPUS-treated ADSCs displayed higher mRNA expression levels of runt-related transcription factor 2 (Runx2),osteocalcin (OCN),ALP and bone sialoprotein (BSP) genes than con-trols,and the protein levels of Runx2 and BSP were also increased.The results suggested that LIPUS may induce the osteogenic differentiation of ADSCs in vitro.

Clinical efficacy of ultrasound-guided pulsed radiofrequency combined with ganglion impar block for treatment of perineal pain

BACKGROUND Ganglion impar block alone or pulsed radiofrequency alone are effective options for treating perineal pain.However,ganglion impar block combined with pulsed radiofrequency(GIB-PRF)for treating perineal pain is rare and the puncture is usually performed with X-ray or computed tomography guidance.AIM To evaluate the safety and clinical efficacy of real-time ultrasound-guided GIBPRF in treating perineal pain.METHODS Thirty patients with perineal pain were included and were treated by GIB-PRF guided by real-time ultrasound imaging between January 2015 and December 2016.Complications were recorded to observe the safety of the ultrasound-guided GIB-PRF procedure,and visual analogue scale(VAS)scores at 24 h before and after treatment and 1,3,and 6 mo later were analyzed to evaluate clinical efficacy.RESULTS Ultrasound-guided GIB-PRF was performed successfully in all patients,and no complications occurred.Compared with pretreatment scores,the VAS scores were significantly lower(P<0.05)at the four time points after treatment.The VAS scores at 1 and 3 mo were slightly lower than those at 24 h(P>0.05)and were significantly lower at 6 mo after treatment(P<0.05).There was a tendency toward lower VAS scores at 6 mo after treatment compared with those at 1 and 3 mo(P>0.05).CONCLUSION Ultrasound-guided GIB-PRF was a safe and effective way to treat perineal pain.The 6-mo short-term clinical efficacy was favorable,but the long-term outcomes need future study.

Non-thermal ablation of rabbit liver VX2 tumor by pulsed high intensity focused ultrasound with ultrasound contrast agent:Pathological characteristics

瞄准：为了调查非热的损坏的病理学的特征，由搏动的高紧张导致了与超声对比代理人(UCA ) 相结合的集中的超声(PHIFU ) ， SonoVue (Bracco 矿泉，米兰，意大利) 在兔子肝 VX2 肿瘤。方法：肝 VX2 肿瘤模型在 20 只兔子被建立，它随机被划分成与超声对比代理人组(PHIFU + UCA 组) 和假冒的组相结合的 PHIFU。在 PHIFU + UCA 组， SonoVue 的 0.2 mL 静脉内地被注入肿瘤，由 ISP 5900 W/cm2 的超声暴露列在后面。兔子在超声暴露以后有天被牺牲。暴露的肿瘤纸巾的标本在轻显微镜和传播电子显微镜下面病理地被获得并且观察。留下的肿瘤纸巾被去请染色的 2,3,5-Triphenyltetrazolium 氯化物(TTC ) 。结果：在染色的 TTC 前，在两个的肿瘤纸巾假冒并且 PHIFU + UCA 组类似于灰色的鱼肉。在染色的 TTC 以后，肿瘤纸巾是一致地染色的红，与在肿瘤织物和正常织物之间的一条清楚的边界。组织学的检查在 PHIFU + UCA 组显示出肿瘤房间损害的符号，与各种各样的尺寸，染色质着边和核固缩的细胞质的液泡。电子显微镜检查揭示了肿瘤房间体积减小，核固缩，染色质着边，拓宽的细胞间隙，在细胞质的高电子密度 apoptotic 身体和液泡的存在。结论：与 UCA 相结合的 PHIFU 的非热的效果能被用来切除兔子肝 VX2 肿瘤。

Low-intensity ultrasound for regeneration of injured peripheral nerve

BACKGROUND: Ultrasound is a kind of mechanical wave and characterized by mechanical effect, heat effect and physical and chemical effect. Ultrasound can promote regeneration of peripheral nerves after a slight injury based on its mechanical effect. However, whether it can promote regeneration of peripheral nerves after a severe injury or not is still unclear. OBJECTIVE: To study the effect of low-intensity ultrasound (LIU) on regeneration of injured peripheral nerve, through examining sciatic nerve function index, the sensory nerve conduction velocity and the thickness of myelin sheath. DESIGN: Single factor design of contrast observation. SETTING: Institute of Ultrasound Engineering, Chongqing Medical University. MATERIALS: A total of 64 female Wistar rats, of clean grade, aged 3 months, weighing 200-250 g, were provided by Experimental Animal Center of Chongqing Medical University. All rats were randomly divided into treatment group and control group with 32 in each group. In addition, rats were observed at 4 time points, including 2, 4, 6 and 8 weeks, with 8 at each time point. The main equipments were detailed as follows: forceps (Medical Treatment Apparatus Company, Chongqing), low-intensity ultrasound treatment instrument (Institute of Ultrasound Engineering in Medicine), the analysis instrument of diagram resembles and arithmetic figure (the United States Bio-RAD Company), ultrasound coupling agent (Xunde Image material factory, Hangzhou), Osmium Tetraoxide (Next Chimica, South Africa). METHODS: The experiment was carried out in Institute of Ultrasound Engineering of Chongqing Medical University from December 2003 to May 2004. The right sciatic nerves of 64 rats were crushed with forceps for 30 s to form the experimental animal models. Then they were treated at 3 days after operation. Rats in the treatment group received the LIU exposure. LIU was applied every other day to the crush site of rats, which had a spatial peak, time-averaged intensity of 0.25 W/cm2 operated at 1 MHz for 1 minute per application for total 8 weeks. At various stages after operation, the sciatic nerve function index(SFI), the sensory nerve conduction velocity and its histology were detected. Rats in the control received a sham exposure. MAIN OUTCOME MEASURES: SFI; sensory nerve conduction velocity; density of myelinated nerve fiber; velocity of nerve regeneration; histological examination. RESULTS: Among 64 Wistar rats, 2 were lost during the experiment and another 2 were supplied. ① Histological examination: Two weeks after treatment, degeneration of axis-cylinder and myelin sheath was obvious in treatment group as compared with that in control group. Within 4-8 weeks after treatment, regeneration of axis-cylinder and myelin sheath of nerve fiber was superior in treatment group to that in control group. At 8 weeks after treatment, axis-cylinder and myelin sheath in treatment group were closed to normal value. Quantity of nerve fiber was less in control group than that in treatment group and the arrangement was disorder. At 2, 4 and 6 weeks after treatment, proliferation of Schwann cells was superior in treatment group to that in control group. At 6 and 8 weeks after treatment, proliferation of fiber tissue in nerve was severer in control group than that in treatment group. ② SFI: At 4, 6 and 8 weeks after treatment, SFI was higher in treatment group than that in control group (t =8.00, 12.41, 15.13, P < 0.01). ③ Sensory nerve conduction velocity: At 2, 4, 6 and 8 weeks after treatment, sensory nerve conduction velocity was faster in treatment group than that in control group (t =11.74, 10.81, 3.51, P < 0.01). ④ Density of myelinated nerve fiber: At 2, 4, 6 and 8 weeks after treatment, density of myelinated nerve fiber was higher in treatment group than that in control group (t =2.16, P < 0.05; t =3.29, 3.52, 3.23, P < 0.01). ⑤ Velocity of nerve regeneration: Velocity of nerve regeneration was (1.50±0.08) mm/d and (1.22±0.10) mm/d of treatment group and control group, respectively. This suggested that velocity of nerve regeneration was faster in treatment group than that in control group (t =2.708, P < 0.05). CONCLUSION: LIU can promote the regeneration of injured peripheral nerve from the appearance, construction, function aspect and functional recovery. Its mechanism may be through the modulation and effect of many links of nerve regeneration process.

Feasibility of low-intensity ultrasound treatment with hydroxylamine to accelerate the initiation of partial nitrification and allow operation under intermittent aeration

Partial nitrification is a key aspect of efficient nitrogen removal,although practically it suf-fers from long start-up cycles and unstable long-term operational performance.To address these drawbacks,this study investigated the effect of low intensity ultrasound treatment combined with hydroxylamine(NH2OH)on the performance of partial nitrification.Results showthat compared with the control group,low-intensity ultrasound treatment(0.10W/mL,15 min)combined with NH2OH(5 mg/L)reduced the time required for partial nitrification initiation by 6 days,increasing the nitrite accumulation rate(NAR)and ammonia nitro-gen removal rate(NRR)by 20.4% and 6.7%,respectively,achieving 96.48% NRR.Mechanis-tic analysis showed that NH2OH enhanced ammonia oxidation,inhibited nitrite-oxidizing bacteria(NOB)activity and shortened the time required for partial nitrification initiation.Furthermore,ultrasonication combined with NH2OH dosing stimulated EPS(extracellular polymeric substances)secretion,increased carbonyl,hydroxyl and amine functional group abundances and enhanced mass transfer.In addition,16S rRNA gene sequencing results showed that ultrasonication-sensitive Nitrospira disappeared from the ultrasound+NH_(2)OH system,while Nitrosomonas gradually became the dominant group.Collectively,the results of this study provide valuable insight into the enhancement of partial nitrification start-up during the process of wastewater nitrogen removal.