Low-field nuclear magnetic resonance relaxation study of the thermal denaturation of transferrins

Lambelet, Pierre; Ducret, F.; Leuba, J. L.; Geoffroy, M.

doi:10.1021/jf00002a013

Cited by 6 publications

(4 citation statements)

References 28 publications

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“…Here, the transverse magnetization relaxation time constant, T 2 , is sensitive to slow molecular motions of water. The denatured and cross-linked proteins caused a significant decrease in the water proton mobility and thereby a decrease in the water proton T 2 (37), which was observed as a darker region in Figure 4. Therefore, MRI provided an alternative, independent, and direct method of measuring protein coagulation (38), and was utilized to verify the uniformity of these in vitro and in vivo thermal lesions.…”

Section: Methodsmentioning

confidence: 95%

Acoustic Droplet Vaporization for Enhancement of Thermal Ablation by High Intensity Focused Ultrasound

Zhang¹,

Fabiilli²,

Haworth³

et al. 2011

Academic Radiology

106

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Rationale and Objectives Acoustic droplet vaporization (ADV) shows promise for spatial control and acceleration of thermal lesion production. Our hypothesis was that microbubbles generated by ADV could enhance high intensity focused ultrasound (HIFU) thermal ablation by controlling and increasing local energy absorption. Materials and Methods Thermal lesions were produced in tissue-mimicking phantoms using focused ultrasound (1.44 MHz) with a focal intensity of 4000 W·cm-2 in degassed water at 37°C. The average lesion volume was measured by visible change in optical opacity and by T2-weighted MRI. In addition, in vivo HIFU lesions were generated in a canine liver before and after an intravenous injection of droplets with a similar acoustic setup. Results Thermal lesions were seven-fold larger in phantoms containing droplets (3×105 droplets/mL) compared to phantoms without droplets. The mean lesion volume with a 2 s HIFU exposure in droplet-containing phantoms was comparable to that made by a 5 s exposure in phantoms without droplets. In the in vivo study, the average lesion volumes without and with droplets were 0.017 ± 0.006 cm3 (n = 4, 5 s exposure) and 0.265 ± 0.005 cm3 (n = 3, 5 s exposure), respectively – a factor of 15 difference. The shape of ADV bubbles imaged with B-mode ultrasound was very similar to the actual lesion shape as measured optically and by MRI. Conclusion ADV bubbles may facilitate clinical HIFU ablation by reducing treatment time or requisite in situ total acoustic power, and provide ultrasonic imaging feedback of the thermal therapy.

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Section: Methodsmentioning

confidence: 95%

Acoustic Droplet Vaporization for Enhancement of Thermal Ablation by High Intensity Focused Ultrasound

Zhang¹,

Fabiilli²,

Haworth³

et al. 2011

Academic Radiology

106

View full text Add to dashboard Cite

show abstract

“…Most published T g data of food materials were obtained using differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA) and dynamic mechanical thermal analysis (DMTA) Karel, 1990, 1991;Lambelet et al, 1991;Kalichevsky et al, 1992ab), which measure thermal or thermomechanical characteristics accompanying the transitions. However, these methods are limited to specific forms and sizes of the test specimens.…”

Section: Introductionmentioning

confidence: 99%

Pulse NMR Study of Glass Transition in Maltodextrin

Ruan

Long

Chen

et al. 1999

Journal of Food Science

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A pulse nuclear magnetic resonance (NMR) technique was used to study the glass transition in maltodextrins. The spin-lattice relaxation time (T 1 ) and spin-spin relaxation time (T 2 ) of different molecular weight maltodextrins at different moisture contents and temperatures were measured using the pulse NMR technique. T 1 and T 2 were plotted against temperatures. From the resultant curves, the state transitions were observed and the corresponding state transition temperatures were determined. The state transition temperatures were very close to the glass transition temperatures (T g s) determined with differential scanning calorimetry, suggesting a strong relationship between glass transition and proton relaxation behavior. Results indicate pulse NMR-based instrumentation could be very effective for the study of glass transition in food polymers.

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“…In MRI, the transverse magnetization relaxation time constant, T 2 , is sensitive to slow molecular motions of water. The denatured and cross-linked proteins caused a significant decrease in the water proton mobility and thereby a decrease in the water proton T 2 (Lambelet et al, 1991), which was observed as a darker region in Fig. 2.…”

Section: (A)] and Then A Spiral Sidewall [3 MM In Thicknessmentioning

confidence: 89%

Acceleration of ultrasound thermal therapy by patterned acoustic droplet vaporization

Kripfgans

Zhang

Fabiilli

et al. 2014

The Journal of the Acoustical Society of America

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One application of acoustic droplet vaporization (ADV), a method of converting biocompatible microdroplets into microbubbles, is to enhance locally high intensity focused ultrasound (HIFU) therapy. Two objectives are pursued here: (1) the controlled creation of a bubble trench prior to HIFU using ADV and (2) use of the trench for increasing ablation volumes, lowering acoustic powers, and decreasing therapy duration. Thermally responsive phantoms were made with perfluorocarbon emulsion. Compound lesions were formed in a laboratory setting and a clinical magnetic resonance imaging (MRI)-guided HIFU system. Linear and spiral patterned compound lesions were generated in trenches. A larger fraction of the HIFU beam is contained to increase the generation of heat. Using the laboratory system, a 90 mm linear length spiral trench was formed in 30 s with mechanical beam steering. Comparatively, the clinical HIFU system formed a 19.9 mm linear length spiral trench in approximately 1 s with electronic beam steering. Lesions were imaged optically and with MRI. A uniform thermal ablation volume of 3.25 mL was achieved in 55.4 s (4-times faster than standard clinical HIFU and 14-times larger volume versus sum of individual lesions). Single lesions showed a 400% volume increase.

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Low-field nuclear magnetic resonance relaxation study of the thermal denaturation of transferrins

Cited by 6 publications

References 28 publications

Acoustic Droplet Vaporization for Enhancement of Thermal Ablation by High Intensity Focused Ultrasound

Acoustic Droplet Vaporization for Enhancement of Thermal Ablation by High Intensity Focused Ultrasound

Pulse NMR Study of Glass Transition in Maltodextrin

Acceleration of ultrasound thermal therapy by patterned acoustic droplet vaporization

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