scholarly journals Effect of high intensity focused ultrasound on neural compound action potential : an in vitro study

2021 ◽  
Author(s):  
Shahrad Jabbary.
Keyword(s):  
Action Potential ◽  
High Intensity ◽  
Focused Ultrasound ◽  
Compound Action Potential ◽  
The Body ◽  
High Intensity Focused Ultrasound ◽  
Acoustic Energy ◽  
Focal Intensity ◽  
Compound Action

Therapeutic ultrasound is a promising field with many novel applications in medicine and biology. High intensity focused ultrasound (HIFU) provides the ability to localize the deposition of acoustic energy within the body by thermal effect. In this work a brief description of how the HIFU system works and how it can be used to produce localized thermal lesions on the pathogenic tissues in the human body will be presented. Results of acoustic characterization of a hand-held HIFU system developed in our lab will also be presented. The capabilities of creating controlled reversible and irreversible changes in the compound action potential (CAP) values of a specific neural tissue, i.e. lobster abdominal nerves by adjusting different ultrasound parameters (intensity, exposure duration, etc.) in the HIFU system will also be described. Lobster abdominal nerves were exposed to a 10s HIFU exposure. The focal intensity values for this study were chosen as 100, 175, 275, 400, 525 and 700 W .cm ⁻². It was shown that a trend of small changes in the measured CAP values (increase in the CAP amplitude) could be achieved in the five intermediate intensities, while a drastic decrease in the measured CAP values and total degeneration of the nerve could be observed with the highest focal intensity of 700 W .cm⁻².

scholarly journals Effect of high intensity focused ultrasound on neural compound action potential : an in vitro study

2021 ◽  
Author(s):  
Shahrad Jabbary.
Keyword(s):  
Action Potential ◽  
High Intensity ◽  
Focused Ultrasound ◽  
Compound Action Potential ◽  
The Body ◽  
High Intensity Focused Ultrasound ◽  
Acoustic Energy ◽  
Focal Intensity ◽  
Compound Action

Therapeutic ultrasound is a promising field with many novel applications in medicine and biology. High intensity focused ultrasound (HIFU) provides the ability to localize the deposition of acoustic energy within the body by thermal effect. In this work a brief description of how the HIFU system works and how it can be used to produce localized thermal lesions on the pathogenic tissues in the human body will be presented. Results of acoustic characterization of a hand-held HIFU system developed in our lab will also be presented. The capabilities of creating controlled reversible and irreversible changes in the compound action potential (CAP) values of a specific neural tissue, i.e. lobster abdominal nerves by adjusting different ultrasound parameters (intensity, exposure duration, etc.) in the HIFU system will also be described. Lobster abdominal nerves were exposed to a 10s HIFU exposure. The focal intensity values for this study were chosen as 100, 175, 275, 400, 525 and 700 W .cm ⁻². It was shown that a trend of small changes in the measured CAP values (increase in the CAP amplitude) could be achieved in the five intermediate intensities, while a drastic decrease in the measured CAP values and total degeneration of the nerve could be observed with the highest focal intensity of 700 W .cm⁻².

scholarly journals Effect of pulsed high intensity focused ultrasound on the nerve compound action potential amplitude and conduction velocity

2021 ◽  
Author(s):  
Steve Tran
Keyword(s):  
Action Potential ◽  
Conduction Velocity ◽  
High Intensity ◽  
Focused Ultrasound ◽  
Compound Action Potential ◽  
Homarus Americanus ◽  
High Intensity Focused Ultrasound ◽  
Nerve Tissue ◽  
Nerve Function ◽  
Compound Action

Therapeutic HIFU has been used as a non-invasive energy modality to compromise nerve function since the 1950s. Several contributions have been made in recent years to characterize these effects on nerve function. In this study, short repeated bursts of HIFU, termed as pulsed high intensity focused ultrasound (pHIFU), was directed at nerve tissue. The pHIFU transducer operated at a central frequency of 1.95 MHz and had a focal length of approximately 12 cm. The ventral nerve cord from the American Lobster (Homarus americanus), n=15, was sonicated cumulatively at 3 exposure times: 1s, 6s, and 16s, at an intensity of 1010 W/cm2, or focal pressure of 5.51 MPa. The compound action potential (CAP) and conduction velocity (CV) were seen to decrease as sonication exposure time to the nerve increased. The experiments performed demonstrate the feasibility to modulate nerve CAP and nerve CV using non-thermal mechanisms of ultrasound.

scholarly journals Effect of pulsed high intensity focused ultrasound on the nerve compound action potential amplitude and conduction velocity

2021 ◽  
Author(s):  
Steve Tran
Keyword(s):  
Action Potential ◽  
Conduction Velocity ◽  
High Intensity ◽  
Focused Ultrasound ◽  
Compound Action Potential ◽  
Homarus Americanus ◽  
High Intensity Focused Ultrasound ◽  
Nerve Tissue ◽  
Nerve Function ◽  
Compound Action

Therapeutic HIFU has been used as a non-invasive energy modality to compromise nerve function since the 1950s. Several contributions have been made in recent years to characterize these effects on nerve function. In this study, short repeated bursts of HIFU, termed as pulsed high intensity focused ultrasound (pHIFU), was directed at nerve tissue. The pHIFU transducer operated at a central frequency of 1.95 MHz and had a focal length of approximately 12 cm. The ventral nerve cord from the American Lobster (Homarus americanus), n=15, was sonicated cumulatively at 3 exposure times: 1s, 6s, and 16s, at an intensity of 1010 W/cm2, or focal pressure of 5.51 MPa. The compound action potential (CAP) and conduction velocity (CV) were seen to decrease as sonication exposure time to the nerve increased. The experiments performed demonstrate the feasibility to modulate nerve CAP and nerve CV using non-thermal mechanisms of ultrasound.

Minimization of treatment time for in vitro 1.1MHz destruction of Pseudomonas aeruginosa biofilms by high-intensity focused ultrasound

Ultrasonics ◽  
2012 ◽  
Vol 52 (5) ◽  
pp. 668-675 ◽  
Author(s):  
Jin Xu ◽  
Timothy A. Bigelow ◽  
Larry J. Halverson ◽  
Jill M. Middendorf ◽  
Ben Rusk
Keyword(s):  
Pseudomonas Aeruginosa ◽  
High Intensity ◽  
Focused Ultrasound ◽  
Treatment Time ◽  
High Intensity Focused Ultrasound

scholarly journals A Doxorubicin-Glucuronide Prodrug Released from Nanogels Activated by High-Intensity Focused Ultrasound Liberated β-Glucuronidase

Pharmaceutics ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 536
Author(s):  
Helena C. Besse ◽  
Yinan Chen ◽  
Hans W. Scheeren ◽  
Josbert M. Metselaar ◽  
Twan Lammers ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Anticancer Drugs ◽  
High Intensity ◽  
Focused Ultrasound ◽  
Anticancer Therapy ◽  
High Intensity Focused Ultrasound ◽  
Low Molecular Weight ◽  
Chemotherapeutic Drug ◽  
The Poor

The poor pharmacokinetics and selectivity of low-molecular-weight anticancer drugs contribute to the relatively low effectiveness of chemotherapy treatments. To improve the pharmacokinetics and selectivity of these treatments, the combination of a doxorubicin-glucuronide prodrug (DOX-propGA3) nanogel formulation and the liberation of endogenous β-glucuronidase from cells exposed to high-intensity focused ultrasound (HIFU) were investigated in vitro. First, a DOX-propGA3-polymer was synthesized. Subsequently, DOX-propGA3-nanogels were formed from this polymer dissolved in water using inverse mini-emulsion photopolymerization. In the presence of bovine β-glucuronidase, the DOX-propGA3 in the nanogels was quantitatively converted into the chemotherapeutic drug doxorubicin. Exposure of cells to HIFU efficiently induced liberation of endogenous β-glucuronidase, which in turn converted the prodrug released from the DOX-propGA3-nanogels into doxorubicin. β-glucuronidase liberated from cells exposed to HIFU increased the cytotoxicity of DOX-propGA3-nanogels to a similar extend as bovine β-glucuronidase, whereas in the absence of either bovine β-glucuronidase or β-glucuronidase liberated from cells exposed to HIFU, the DOX-propGA3-nanogels hardly showed cytotoxicity. Overall, DOX-propGA3-nanogels systems might help to further improve the outcome of HIFU-related anticancer therapy.

scholarly journals Localized delivery of compounds into articular cartilage by using high-intensity focused ultrasound

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Heikki J. Nieminen ◽  
Eetu Lampsijärvi ◽  
Gonçalo Barreto ◽  
Mikko A. J. Finnilä ◽  
Ari Salmi ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Articular Cartilage ◽  
High Intensity ◽  
Focused Ultrasound ◽  
Pulse Repetition Frequency ◽  
High Intensity Focused Ultrasound ◽  
Positive Pressure ◽  
Mechanical Index ◽  
Localized Delivery

Abstract Localized delivery of drugs into an osteoarthritic cartilaginous lesion does not yet exist, which limits pharmaceutical management of osteoarthritis (OA). High-intensity focused ultrasound (HIFU) provides a means to actuate matter from a distance in a non-destructive way. In this study, we aimed to deliver methylene blue locally into bovine articular cartilage in vitro. HIFU-treated samples (n = 10) were immersed in a methylene blue (MB) solution during sonication (f = 2.16 MHz, peak-positive-pressure = 3.5 MPa, mechanical index = 1.8, pulse repetition frequency = 3.0 kHz, cycles per burst: 50, duty cycle: 7%). Adjacent control 1 tissue (n = 10) was first pre-treated with HIFU followed by immersion into MB; adjacent control 2 tissue (n = 10) was immersed in MB without ultrasound exposure. The MB content was higher (p < 0.05) in HIFU-treated samples all the way to a depth of 600 µm from AC surface when compared to controls. Chondrocyte viability and RNA expression levels associated with cartilage degeneration were not different in HIFU-treated samples when compared to controls (p > 0.05). To conclude, HIFU delivers molecules into articular cartilage without major short-term concerns about safety. The method is a candidate for a future approach for managing OA.

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