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Your search keyword '"Doukas, Apostolos G."' showing total 176 results
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176 results on '"Doukas, Apostolos G."'

1. Physical factors involved in stress-wave-induced cell injury: The effect of stress gradient

Author

Doukas, Apostolos G, McAuliffe, Daniel J, Lee, Shun, Venugopalan, Vasan, and Flotte, Thomas J

Subjects
Biomedical and Clinical Sciences, Clinical Sciences, Cancer, Physical Injury - Accidents and Adverse Effects, Breast Cancer, Animals, Cell Survival, Female, Laser Therapy, Mammary Neoplasms, Experimental, Mice, Pressure, Thymidine, Tumor Cells, Cultured, ABLATION, PHOTOACOUSTICS, SHOCK WAVES, STRESS GRADIENT, CELL VIABILITY, MEMBRANE PERMEABILITY, Acoustics, Clinical sciences
Abstract

We have studied the biological effects of ablation-induced stress waves in vitro. Mouse breast sarcoma cells (EMT-6) were exposed to stress waves that differed only in rise time. Two assays were used to determine cell injury: incorporation of tritiated thymidine (viability assay), and transmission electron microscopy (morphology assay). We present evidence that the rise time of stress waves can significantly modify cell viability and that cell injury correlates better with the stress gradient than peak stress.

Published
1995

11. Photodynamic Therapy for Endodontic Disinfection

Author

Soukos, Nikolaos S., Chen, Peter Shih-Yao, Morris, Jason T., Ruggiero, Karriann, Abernethy, Abraham D., Som, Sovanda, Foschi, Federico, Doucette, Stephanie, Luschke Bammann, Lili, Fontana, Carla Raquel, Doukas, Apostolos G., and Stashenko, Philip P.

Published
2006
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19. Picosecond grating spectroscopy for characterizing the acoustic properties of biological material

Author

Lamb, Don C., Lin, Gloria C., and Doukas, Apostolos G.

Subjects
Ultrasonics -- Research, Laser pulses, Ultrashort -- Research, Spectrum analysis -- Innovations, Astronomy, Physics
Abstract

We present measurements of the ultrasound attenuation and sound velocity of a number of liquids, transparent biological materials (the vitreous and lens of the bovine eye), and biological fluids (whole blood) at frequencies between 925 and 1020 MHz by using a picosecond thermal grating. Sound velocity and attenuation measurements of liquids (e.g., methanol and ethanol) agree very well with those reported in the literature. The sound velocity in the biological materials studied also agrees with the reported values in the literature. In contrast, the attenuation coefficients measured for biological materials, 2000-5000 dB/cm, are much higher than would be extrapolated from published low-frequency data. Key words: Ultrasound attenuation, ultrasound, vitreous, blood, sound velocity, ultrasonic frequency dependence, thermal grating spectroscopy, laser ultrasound.

Published
1997

28. Fractional laser-assisted drug delivery:Active filling of laser channels with pressure and vacuum alteration

Author

Erlendsson, Andrés M, Doukas, Apostolos G, Farinelli, William A, Bhayana, Brijesh, Anderson, R Rox, Haedersdal, Merete, Erlendsson, Andrés M, Doukas, Apostolos G, Farinelli, William A, Bhayana, Brijesh, Anderson, R Rox, and Haedersdal, Merete

Abstract

BACKGROUND AND OBJECTIVE: Ablative fractional laser (AFXL) is rapidly evolving as one of the foremost techniques for cutaneous drug delivery. While AFXL has effectively improved topical drug-induced clearance rates of actinic keratosis, treatment of basal cell carcinomas (BCCs) has been challenging, potentially due to insufficient drug uptake in deeper skin layers. This study sought to investigate a standardized method to actively fill laser-generated channels by altering pressure, vacuum, and pressure (PVP), enquiring its effect on (i) relative filling of individual laser channels; (ii) cutaneous deposition and delivery kinetics; (iii) biodistribution and diffusion pattern, estimated by mathematical simulation.METHODS: Franz diffusion chambers (FCs) were used to evaluate the PVP-technique, comparing passive (AFXL) and active (AFXL + PVP) channel filling. A fractional CO2-laser generated superficial (225 µm;17.5 mJ/channel) and deep (1200 µm; 130.5 mJ/channel) channels, and PVP was delivered as a 3-minutes cycle of 1 minute pressure (+1.0 atm), 1 minute vacuum (-1.0 atm), and 1 minute pressure (+1.0 atm). Filling of laser channels was visualized with a colored biomarker liquid (n = 12 FCs, n = 588 channels). Nuclear magnetic resonance quantified intracutaneous deposition of topically applied polyethylene glycol (PEG400) over time (10 minutes, 1 hour, and 4 hours), investigated with (n = 36 FCs) and without (n = 30 FCs) PVP-filling. Two-dimensional mathematical simulation was used to simulate intradermal biodistribution and diffusion at a depth of 1,000 µm.RESULTS: Active filling with application of PVP increased the number of filled laser channels. At a depth of 1,000 µm, filling increased from 44% (AFXL) to 94% with one PVP cycle (AFXL + PVP; P < 0.01). Active filling greatly enhanced intracutaneous deposition of PEG400, resulting in a rapid delivery six-folding uptake at 10 minutes (AFXL 54 µg/ml vs. AFXL + PVP 303 µg/ml, P < 0.01). AFXL alo

Published
2016

29. Micro‐fractional, directional skin tightening: A porcine model

Author

Russe, Elisabeth, primary, Purschke, Martin, additional, Farinelli, William A., additional, Wang, Ying, additional, Doukas, Apostolos G., additional, Limpiangkanan, Wikunda, additional, Sakamoto, Fernanda H., additional, Tam, Joshua, additional, Wechselberger, Gottfried, additional, and Anderson, Richard Rox, additional

Published
2015
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32. Fractional laser-assisted delivery of methyl aminolevulinate:Impact of laser channel depth and incubation time

Author

Haak, Christina S, Farinelli, William A, Tam, Joshua, Doukas, Apostolos G, Anderson, R Rox, Haedersdal, Merete, Haak, Christina S, Farinelli, William A, Tam, Joshua, Doukas, Apostolos G, Anderson, R Rox, and Haedersdal, Merete

Abstract

Pretreatment of skin with ablative fractional lasers (AFXL) enhances the uptake of topical photosensitizers used in photodynamic therapy (PDT). Distribution of photosensitizer into skin layers may depend on depth of laser channels and incubation time. This study evaluates whether depth of intradermal laser channels and incubation time may affect AFXL-assisted delivery of methyl aminolevulinate (MAL).

Published
2012

33. Fractional CO(2) laser-assisted drug delivery

Author

Haedersdal, Merete, Sakamoto, Fernanda H, Farinelli, William A, Doukas, Apostolos G, Tam, Josh, Anderson, R Rox, Haedersdal, Merete, Sakamoto, Fernanda H, Farinelli, William A, Doukas, Apostolos G, Tam, Josh, and Anderson, R Rox

Abstract

Ablative fractional resurfacing (AFR) creates vertical channels that might assist the delivery of topically applied drugs into skin. The purpose of this study was to evaluate drug delivery by CO(2) laser AFR using methyl 5-aminolevulinate (MAL), a porphyrin precursor, as a test drug.

Published
2010

34. Fractional Skin Harvesting

Author

Tam, Joshua, primary, Wang, Ying, additional, Farinelli, William A., additional, Jiménez-Lozano, Joel, additional, Franco, Walfre, additional, Sakamoto, Fernanda H., additional, Cheung, Evelyn J., additional, Purschke, Martin, additional, Doukas, Apostolos G., additional, and Anderson, R. Rox, additional

Published
2013
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35. Selective photothermolysis to target sebaceous glands: Theoretical estimation of parameters and preliminary results using a free electron laser

Author

Sakamoto, Fernanda H., primary, Doukas, Apostolos G., additional, Farinelli, William A., additional, Tannous, Zeina, additional, Shinn, Michelle, additional, Benson, Steve, additional, Williams, Gwyn P., additional, Gubeli, Joseph F., additional, Dylla, H. Frederick, additional, and Anderson, R. Rox, additional

Published
2011
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38. Phototargeting Oral Black-Pigmented Bacteria

Author

Soukos, Nikolaos S., primary, Som, Sovanda, additional, Abernethy, Abraham D., additional, Ruggiero, Karriann, additional, Dunham, Joshua, additional, Lee, Chul, additional, Doukas, Apostolos G., additional, and Goodson, J. Max, additional

Published
2005
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43. Pressure Waves in Medicine: From Tissue Injury to Drug Delivery.

Author

Doukas, Apostolos G.

Subjects
*WAVES (Physics), *PRESSURE, *THERAPEUTICS, *CLINICAL medicine, *KIDNEY stones, *TISSUES, *CELLS, *BIOLOGY
Abstract

Pressure waves have the potential to cause injury to cells and tissue or enable novel therapeutic modalities, such as fragmentation of kidney stones and drug delivery. Research on the biological effects of pressure waves have shown that the biological response on depends the pressure-wave characteristics. One of the most prominent effects induced by pressure waves is the permeabilization of a number of barrier structures (cell plasma membrane, skin and microbial biofilms) and facilitate the delivery of macromolecules. The permeabilization of the barrier structure is transient and the barrier function recovers. Thus, pressure waves can induce delivery of molecular species that would not normally cross the barrier structure. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]

Published
2004
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