| In-vitro Retinal Model Reveals a Sharp Transition between Laser Damage Mechanisms |
07 May 2010 |
4 pages |
| Authors:
Michael L Denton; Clark; C D III; Michael S Foltz; Kurt J Schuster; Gary D Noojin; Larry E Estlack; Robert J Thomas; NORTHROP GRUMMAN CORP SAN ANTONIO TX INFORMATION TECHNOLOGY
|
 | We determined laser damage thresholds at 413 nm using a novel environmentally controlled enclosure and a previously described artificially pigmented RPE cell model. Exposure duration ranged from 0.1 to 200 s for a 0.3-mm beam, and 100 to 200 s for a 2.5-mm beam. We found substantial differences between the thresholds for the two beam sizes, which we attribute to a continuing thermal contribution with the larger beam. To better ... |
|
| An in vitro Corneal Model with a Laser Damage Threshold at 2 Micrometers That is Similar to That in the Rabbit |
Nov-2007 |
13 pages |
| Authors:
Robert J Thomas; Michael S Foltz; Michael L Denton; Kurt J Schuster; Larry E Estlack; NORTHROP GRUMMAN SAN ANTONIO TX
|
| Corneal organotypic cultures were generated as per existing methods, which included growth on polycarbonate inserts and air-lifting for one week. The corneal simulant cultures were exposed, with real-time IR imaging, to the 2-micron wavelength output of a thulium fiber laser with 4 mm beam diameter for 0.25 seconds in a thermally controlled environment and then assayed for damage. The in vitro threshold (ED50 value of 12.5 W/sq cm) and peak ... |
|
| Role of Superoxide Dismutase in the Photochemical Response of Cultured RPE Cells to Laser Exposure at 413 nm |
Nov-2007 |
9 pages |
| Authors:
Michael L Denton; Michael S Foltz; Kurt J Schuster; Larry E Estlack; Robert J Thomas; NORTHROP GRUMMAN SAN ANTONIO TX WARFIGHTER CONCEPTS AND APPLICATIONS DEPT
|
| Thresholds for photochemical damage were performed in RPE cell lines (artificially pigmented) taken from either human (hTERT-RPE1), wild type (wt) mouse, or transgenic mice deficient (+/-) in either superoxide dismutase 1 (SOD1) or SOD2. The four cell lines were characterized by immunohistochemical and immunoblot analyses to determine relative abundance of the SOD proteins. There was no difference in sensitivity between the human, murine wt and murine SOD1-deficient cells, whereas there ... |
|
| An In Vitro Model for Retinal Laser Damage |
Jan 2007 |
9 pages |
| Authors:
Michael L Denton; Michael S Foltz; Kurt J Schuster; Larry E Estlack; Harvey M Hodnett; Gary D Noojin; Robert J Thomas; NORTHROP GRUMMAN SAN ANTONIO TX WARFIGHTER CONCEPTS AND APPLICATIONS DEPT
|
| Ocular laser exposures resulting in damage at the retina typically involve cellular alterations in the retinal pigment epithelial (RPE) layer. To provide guidelines for eye-safe exposure to lasers, the laser safety community has relied on damage assessment in nonhuman primate studies. Simple and reliable model systems for laser bioeffects that use cultured RPE cells, rather than animals, are thus desirable. We have characterized our artificially pigmented hTERT-RPE I model by ... |
|
| Damage Thresholds for Exposure to NIR and Blue Lasers in an In Vitro RPE Cell System |
Jul 2006 |
10 pages |
| Authors:
Michael L Denton; Michael S Foltz; Larry E Estlack; David J Stolarski; Gary D Noojin; Robert J Thomas; Debbie Eikum; Benjamin A Rockwell; AIR FORCE RESEARCH LAB BROOKS AFB TX OPTICAL RADIATION
|
| Until reliable nonanimal systems of analysis are available, animal models will be necessary for ocular laser hazard analysis and for evaluating clinical applications. The purpose of this work was to demonstrate the utility of an in vitro system for laser bioeffects by identifying photothermal and photochemical cytotoxicity thresholds for continuous-wave (cw) and mode-locked (ml) laser exposures. Exogenous melanosomes were added to hTERT-RPE1 cells in exposure wells 1 day before laser ... |
|
| Photochemical Damage from Chronic 458-nm Laser exposures in an Artificially Pigmented hTERT-RPE1 Cell Line |
Feb 2006 |
13 pages |
| Authors:
Michael S Foltz; Norris A Whitlock; Larry E Estlack; Manuel A Figueroa; Robert J Thomas; Benjamin A Rockwell; Michael L Denton; AIR FORCE RESEARCH LAB BROOKS AFB TX OPTICAL RADIATION
|
| Artificially pigmented hTERT-RPE1 cells were exposed to a mode-locked or continuous wave (CW) laser at 458 run for one hour in a modified culture incubator. Exposure conditions were selected to give greatest likelihood of damage due to a photochemical mechanism, with interest in possible differences between CW and mode-locked damage thresholds. After post-exposure-recovery (PER) for either 1-hour or 24-hour, cells were concurrently stained with annexin V and 6-CFDA to determine ... |
|
| Detection of 2-Photon Oxidation from a NIR Laser Using Confocal Microscopy |
Jan 2006 |
10 pages |
| Authors:
Kurt J Schuster; Larry E Estlack; Benjamin A Rockwell; Michael L Denton; AIR FORCE RESEARCH LAB BROOKS AFB TX OPTICAL RADIATION
|
| Recent studies have determined that photochemical oxidation in cultured cells can be detected at peak irradiances as low as 8.5x10(8) W cm(-2) (87-fs pulse). Fluorescent dyes, such as CM-H(2)DCFDA, enable us to quantify the oxidation response of cells to mode-locked near-infrared (NIR) laser exposure. Using a modified confocal microscope, we characterize the time-dependent 2-photon induced fluorescence generated from a given NIR laser exposure. When cultured cells were then pre-loaded with ... |
|
Reports by Author
