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ultrasound and mechanical sensitive channel

Lu Zhao, Yi Feng, Aiwei Shi, Yujin Zong, Mingxi Wan
Acoustic cavitation of microbubbles has been described as inducing tumor cell apoptosis that is partly associated with mitochondrial dysfunction; however, the exact mechanisms have not been fully characterized. Here, low-intensity pulsed ultrasound (1 MHz, 0.3-MPa peak negative pressure, 10% duty cycle and 1-kHz pulse repetition frequency) was applied to K562 chronic myelogenous leukemia cells for 1 min with 10% (v/v) SonoVue microbubbles. After ultrasound exposure, the apoptotic index was determined by flow cytometry with annexin V-fluorescein isothiocyanate/propidium iodide...
October 2015: Ultrasound in Medicine & Biology
Young Cho, Cheng-Chung Chang, Jaesok Yu, Mansik Jeon, Chulhong Kim, Lihong V Wang, Jun Zou
The development of the first miniaturized parallel acoustic delay line (PADL) probe for handheld photoacoustic tomography (PAT) is reported. Using fused-silica optical fibers with low acoustic attenuation, we constructed two arrays of eight PADLs. Precision laser micromachining was conducted to produce robust and accurate mechanical support and alignment structures for the PADLs, with minimal acoustic distortion and interchannel coupling. The 16 optical-fiber PADLs, each with a different time delay, were arranged to form one input port and two output ports...
August 2014: Journal of Biomedical Optics
Zita Petrovszki, Gábor Adam, Gabriella Kekesi, Gábor Tuboly, Zita Morvay, Endre Nagy, György Benedek, Gyöngyi Horvath
Capsaicin desensitization leads to behavioral changes, some of which are related to schizophrenia, but investigations into these effects have been scarce. The goal of this study was to characterize the consequences of juvenile capsaicin desensitization on different functions: acute and inflammation-induced thermal and mechanical sensitivity, urinary bladder capacity and thermoregulation, and also on the potentially schizophrenia-related impairments in sensory-motor gating, motor activity and cognitive functioning...
February 10, 2014: Physiology & Behavior
M Daugschies, K Rohde, C-C Glüer, R Barkmann
Our objective is to evaluate an ultrasound probe for measurements of velocity and anisotropy in human cortical bone (tibia). The anisotropy of cortical bone is a known and mechanically relevant property in the context of osteoporotic fracture risk. Current in vivo quantitative ultrasound devices measuring the velocity of ultrasound in long bones can only be applied in the axial direction. For anisotropy measurements a second direction for velocity measurements preferably perpendicular to the axial direction is necessary...
January 2014: Ultrasonics
Wei Lu, Oleg A Sapozhnikov, Michael R Bailey, Peter J Kaczkowski, Lawrence A Crum
The mechanism of the twinkling artifact (TA) that occurs during Doppler ultrasound imaging of kidney stones was investigated. The TA expresses itself in Doppler images as time-varying color. To define the TA quantitatively, beam-forming and Doppler processing were performed on raw per channel radio-frequency data collected when imaging human kidney stones in vitro. Suppression of twinkling by an ensemble of computer-generated replicas of a single radio frequency signal demonstrated that the TA arises from variability among the acoustic signals and not from electronic signal capture or processing...
June 2013: Ultrasound in Medicine & Biology
Ken-Ichi Serizawa, Kenji Yogo, Ken Aizawa, Yoshihito Tashiro, Yoko Takahari, Kaori Sekine, Toshihiko Suzuki, Nobuhiko Ishizuka, Hideyuki Ishida
Paclitaxel-eluting stents dramatically reduce rates of in-stent restenosis; however, paclitaxel is known to lead to endothelial dysfunction. Protective effects of nicorandil on paclitaxel-induced endothelial dysfunction by examining flow-mediated dilation (FMD) were investigated in anesthetized rats. After 7-day osmotic infusion of paclitaxel (5 mg/kg per day), FMD was measured by high-resolution ultrasound in the femoral artery of living rats. Paclitaxel significantly reduced FMD (21.6% ± 3.2% to 7.1% ± 1...
2012: Journal of Pharmacological Sciences
A Payne, R Merrill, E Minalga, U Vyas, J de Bever, N Todd, R Hadley, E Dumont, L Neumayer, D Christensen, R Roemer, D Parker
PURPOSE: This work presents the design and preliminary evaluation of a new laterally mounted phased-array MRI-guided high-intensity focused ultrasound (MRgHIFU) system with an integrated 11-channel phased-array radio frequency (RF) coil intended for breast cancer treatment. The design goals for the system included the ability to treat the majority of tumor locations, to increase the MR image's signal-to-noise ratio (SNR) throughout the treatment volume and to provide adequate comfort for the patient...
March 2012: Medical Physics
Eleanor M Martin, Francis A Duck, C Peter Winlove
We have previously shown that MHz frequency ultrasound causes contraction of the carotid artery in vitro. We now extend this investigation to equine mesenteric arteries and investigate the cellular mechanisms. In vitro exposure of the large lateral cecal mesenteric artery to 4-min periods of 3.2 MHz continuous wave ultrasound at acoustic powers up to 145 mW induced reversible repeatable contraction. The magnitude of the response was linearly dependent on acoustic power and, at 145 mW, the mean increase in wall stress was 0...
January 2012: Ultrasound in Medicine & Biology
Mohamed El-Dib, An N Massaro, Penny Glass, Dorothy Bulas, Nadia Badrawi, Azza Orabi, Hany Aly
OBJECTIVE: Amplitude integrated electroencephalography (aEEG) has been used in neonates in various clinical and research applications. We hypothesized that an abnormal aEEG score could be used as a predictor of short-term adverse outcome. METHODS: Very low birth weight infants were enrolled in a prospective observational cohort study. Two channel 12-hour continuous aEEG recordings were performed within 48 h of life and at 1 week of age. Recordings were classified as abnormal if they correspond to a 2 point difference in score...
June 2011: Pediatrics International: Official Journal of the Japan Pediatric Society
Miao Yu, Hans H Funke, John L Falconer, Richard D Noble
Gated ion diffusion is found widely in hydrophobic biological nanopores, upon changes in ligand binding, temperature, transmembrane voltage, and mechanical stress. Because water is the main media for ion diffusion in these hydrophobic biological pores, ion diffusion behavior through these nanochannels is expected to be influenced significantly when water wettability in hydrophobic biological nanopores is sensitive and changes upon small external changes. Here, we report for the first time that ion diffusion through highly hydrophobic nanopores (approximately 3 nm) showed a gated behavior due to change of water wettability on hydrophobic surface upon small temperature change or ultrasound...
June 23, 2010: Journal of the American Chemical Society
Shawn B Bender, Johnathan D Tune, Lena Borbouse, Xin Long, Michael Sturek, M Harold Laughlin
Onset of the combined metabolic syndrome (MetS) is a complex progressive process involving numerous cardiovascular risk factors. Although patients with established MetS exhibit reduced coronary flow reserve and individual components of the MetS reduce microvascular vasodilation, little is known concerning the impact of early-stage MetS on the mechanisms of coronary flow control. Therefore, we tested the hypothesis that coronary arteriolar dilation to adenosine is attenuated in early-stage MetS by reduced A2 receptor function and diminished K+ channel involvement...
June 2009: Experimental Biology and Medicine
M M Galagudza, A A Shmonin, K A Mishchenko, T D Vlasov, N N Petrishchev
It has been shown that exposure of the isolated rat heart perfused according to Langendorff to therapeutic ultrasound (210 kHz and 0.5-1.5 W/cm2 ) induces a cardioprotective response similar to ischemic preconditioning. This reduces the infarct size and improves the postischemic systolic and diastolic function. The ATP-sensitive K+ channel blocker glybenclamide abolished the protection afforded by ultrasound; in contrast, the free radical scavenger N-2-MPG did not influence the ultrasound-induced cardioprotective response...
July 2008: Biofizika
Han-Yu Chen, Jiann-Jong Liau, Chung-Li Wang, Hung-Jen Lai, Mei-Hwa Jan
Electromechanical delay (EMD) of the vastus medialis obliquus (VMO) and vastus lateralis (VL) is determined by measuring the interval between the time of onset of muscle activities and the time of onset of mechanical output. However, individual mechanical output of the VMO or the VL cannot be obtained with the conventional method because of the knee extension force as the mechanical output. Therefore, the objective of the present study was to develop a new method for measuring EMD of the VMO and VL individually...
January 2009: Ultrasound in Medicine & Biology
Tauseef Ali, Philip B Miner
PURPOSE OF REVIEW: Gastroesophageal reflux disease is a highly prevalent chronic condition in Western populations. It has a profound effect on our society in terms of economic cost and quality of life. There have been major advances in understanding of disease pathogenesis over the last few years which are summarized in this article. RECENT FINDINGS: With improved understanding of gastroesophageal reflux disease, newer developments in diagnostic techniques have evolved...
July 2008: Current Opinion in Gastroenterology
Laurent B Nicolas, Steffen Klein, Eric P Prinssen
RATIONALE: In rats, dorsal periaqueductal gray (dPAG) stimulation elicits escape behavior that is thought to be related to fear and panic. A noninvasive technique--exposure to ultrasound-has been reported to stimulate the dPAG and induce escape followed by freezing in Lister-hooded (LH) rats. OBJECTIVE: Further characterize pharmacologically the ultrasound--induced defensive behaviors test with anxiolytics acting via different mechanisms. MATERIALS AND METHODS: LH rats, treated with clinically validated anxiolytics, putative anxiolytics, or compounds devoid of anxiolytic properties, were exposed to ultrasound...
October 2007: Psychopharmacology
T A Tran, S Roger, J Y Le Guennec, F Tranquart, A Bouakaz
New clinical applications of ultrasound contrast microbubbles extend beyond imaging and diagnosis toward therapeutic applications. Cell membrane permeability and the uptake of substances have been shown to be enhanced by microbubbles under ultrasound stimulation. However, the mechanisms of action of ultrasound-activated microbubbles are still unknown. The aim of our study was to examine how microbubbles and ultrasound interact with cells in an attempt to understand the sonoporation mechanism. The ruptured-patch-clamp whole-cell technique was used to measure membrane potential variations of a single cell...
January 2007: Ultrasound in Medicine & Biology
William G Schrage, Niki M Dietz, Michael J Joyner
ATP-sensitive potassium (KATP) channels have been suggested to contribute to coronary and skeletal muscle vasodilation during exercise, either alone or interacting in a parallel or redundant process with nitric oxide (NO), prostaglandins (PGs), and adenosine. We tested the hypothesis that KATP channels, alone or in combination with NO and PGs, regulate exercise hyperemia in forearm muscle. Eighteen healthy young adults performed 20 min of moderate dynamic forearm exercise, with forearm blood flow (FBF) measured via Doppler ultrasound...
May 2006: Journal of Applied Physiology
Goksen G Yaralioglu, Ira O Wygant, Theodore C Marentis, Butrus T Khuri-Yakub
This paper presents a microfluidic mixer that uses acoustic stirring created by ultrasonic waves. The ultrasound is introduced into the channel by integrated piezoelectric transducers. The transducers are made of a zinc oxide thin film, which is deposited on the bottom surface of a quartz substrate. The poly(dimethylsiloxane) channel is aligned to the transducers on the top surface of the substrate. The transducers are designed for operation around 450 MHz. The main mechanism of the mixing is the acoustic stirring of the fluid perpendicular to the flow direction...
July 1, 2004: Analytical Chemistry
Wen-Hua Du, Wei-Xiao Yang, Xiang Wang, Xiu-Qin Xiong, Yi Zhou, Tao Li
AIM: To investigate the possible clinical application value of second harmonic imaging under low acoustic pressure. METHODS: Six New Zealand rabbits, averaging 2.7+/-0.4 kg, were selected and operated upon to construct hepatic VX2 tumor carrier model. Hepatic VX2 tumors were imaged with B mode Ultrasonography (US), and second harmonic imaging (SHI) under high mechanic index (1.6) and low mechanic index (0.1). Echo agent was intravenously injected through ear vein at a dose of 0...
August 2003: World Journal of Gastroenterology: WJG
K Akahoshi, A Kondoh, T Nagaie, N Koyanagi, K Nakanishi, N Harada, H Nawata
BACKGROUND: Conventional echoendoscopes have disadvantages when used for staging colorectal cancer including the inability to pass the instrument through tight stenosis and limited maneuverability. This study evaluated the preoperative use of a newly developed 7.5 MHz front-loading ultrasound probe (FLUP) for local staging of rectal cancer. METHODS: A 7.5 MHz FLUP, diameter 7.3 mm, was used in this study. The mechanical shaft portion of the probe can be passed in retrograde fashion through the accessory channel of a standard colonoscope...
October 2000: Gastrointestinal Endoscopy
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