Faculty Bibliography

Background: A variety of parameters with LED photomodulation can alter cellular response in vitro. The effects of one visible and one infrared wavelength were evaluated to determine the optimal ratio to produce a net increase in dermal collagen by altering the ratio of total energy output of each wavelength. The ratio between the two wavelengths (595 nm and 870 nm) was shifted in 25% increments. Study: Human dermal fibroblasts in culture were exposed to a 595/870 nm LED array with total combined energy density fixed at 4.0 mW/cm². The ratio of 595/870 nm parameters were: 100%/ 0%; 75%/25%; 50%/50%; 25%/75%; and 0%/100%. These ratios were tested using pulsed duty cycle of exposure (250 msec 'on' time/100 msec 'of f time/100 pulses) and examined using commercially available extra cellular matrix and adhesion molecule RT PCR Arrays (SI Biosciences) for gene expression 24 hours post exposure. Results: There were different expression prof iles noticed for each of the ratios studied. Overall, there was an average (in an 80 gene array) of 6% directional expression difference. The greatest increase in Collagen I and decrease in Collagenase (MMP-1) was observed with 75%/25% ratio of 595/870 nm. The addition of increasing ratios of IR wavelengths causes an alteration in the gene expression prof ile. Even when the genes followed the same directional change, the ratios of the wavelengths caused variation in magnitude of expression. Conclusion: Varying the ratios of specific wavelength intensity in multiwavelength light therapy can alter the resulting gene expression patterns

Background: Delivery of pulsed or continuous wave 590/870 nm LED light modulates the production of procollagen I by human dermal fibroblasts in vitro. In pulsed mode, the number of pulses and exposure or on time of the LED pulsed mode the duty cycle determines the energy fluence delivered to the target. In continuous wave mode, the cumulative exposure time determines the energy fluence delivered to the target. Study: Human dermal fibroblasts in culture were exposed to a 590/870 nm LED array with an energy density of 3.8 mW/cm².In the pulsed mode, a matrix of exposure parameters were tested including: msec 'on times of 1 (single pulse), 10, 100, 250, 500, 1000; msec with 'of f times of 10, 100, 250, 500, 1000; and total number of pulses of 1, 10, 100, 250, 500, 1000. In continuous wave mode, a range of fourteen exposure times from 0.5 to 10⁶ msec were tested. Four days after exposure, supernatants from the exposed fibroblasts were assayed by ELISA for procollagen I production. Results: For pulsed parameters, procollagen production was highest for energy fluence of 0.01-0.24 J/cm² with a peak around 0.1 J/cm² for parameters of 250/100/100 (msec on/msec/of f/# pulses). Continuous wave highest peaks were at 100 msec and 10,000 msec (0.0004 and 0.04 J/cm² respectively. Conclusion: 0.1 J/cm² using a pulsed 590/870 nm LED parameters of 250 msec 'on' 100 msec 'of f 100 pulses was selected as most effective for procollagen I production

Background: The effect of exposure to various pulsed and continuous wave Treatments on human dermal fibroblasts in vitro was studied using ELISA assay procollagen I production as the endpoint measurement. The study was designed to evaluate the complex interactions that occur between the light source and the cell. Study: Human dermal fibroblasts in culture were exposed to a 590/870 nm LED array fixed at 3.8 mW/cm². In the pulsed mode, a matrix of exposure parameters was tested including: msec exposure 'on' times of 1 (single pulse), 10, 100, 250, 500, 1000; msec 'of f times of 10,100, 250, 500, 1000; and total pulse numbers of 1, 10, 100, 250, 500, 1000. In continuous wave mode, a range of fourteen exposure times from 0.5 to 106 msec were tested. Four days after exposure, supernatants from the exposed fibroblasts were collected and assayed. Results: Measuring percent change from control, the parameters tested produced a wide range of responses from 0% change to greater than 90% increase in procollagen I. Pulse duty cycles (msec 'on') of 100 and 250, and msec 'of f of 10 and 100, and number of 100 pulses produced the most procollagen, as did 100 msec and 10,000 msec in continuous wave mode. Conclusion: These experiments show that procollagen production by human dermal fibroblasts in vitro can be modulated using pulsed and continuous wave modes. Responses to pulsed modes reveal a more complex pattern of cellular response to light than continuous wave mode

The field of nonsurgical laser resurfacing for aesthetic enhancement continues to improve with new research and technological advances. Since its beginnings in the 1980s, the laser-resurfacing industry has produced a multitude of devices employing ablative, nonablative, and fractional ablative technologies. The three approaches largely differ in their method of thermal damage, weighing degrees of efficacy, downtime, and side effect profiles against each other. Nonablative technologies generate some interest, although only for those patient populations seeking mild improvements. Fractional technologies, however, have gained dramatic ground on fully ablative resurfacing. Fractional laser resurfacing, while exhibiting results that fall just short of the ideal outcomes of fully ablative treatments, is an increasingly attractive alternative because of its far more favorable side effect profile, reduced recovery time, and significant clinical outcome.

OBJECTIVE: To evaluate the efficacy and safety of darbepoetin alfa dosed every-other-week (Q2W) to treat anemia in subjects with chronic kidney disease (CKD), not receiving dialysis, who were naive to erythropoiesis-stimulating agent (ESA) therapy. RESEARCH DESIGN AND METHODS: This was an open-label, multicenter, single-arm study enrolling ESA-naive CKD subjects with baseline hemoglobin (Hb) < 11.0 g/dL. Q2W darbepoetin alfa treatment was initiated at a dose of 0.75 microg/kg and titrated to achieve and maintain Hb levels at 11.0-13.0 g/dL. Treatment was administered from week 1 to week 19. MAIN OUTCOME MEASURES: The primary endpoint was the proportion of subjects who achieved Hb > or = 11 g/dL at any study visit, except in week 1. Hb levels, darbepoetin alfa dose, and safety were also assessed. RESULTS: Of the 128 subjects who received at least one dose of darbepoetin alfa and of the subjects who completed the study, 118 (92%) and 112 (97%), respectively, achieved a Hb > or = 11 g/dL in a median time of 5 weeks. Median darbepoetin alfa dose at week 1 and at the time of achieving a Hb > or = 11 g/dL were 60 and 80 microg, respectively. Darbepoetin alfa was well-tolerated, and short-term adverse events were consistent with those expected in CKD subjects. CONCLUSIONS: This study demonstrates that de novo Q2W darbepoetin alfa was effective in correcting and maintaining Hb levels in ESA-naive subjects with CKD who were not receiving dialysis. Study limitations, including lack of a control arm for the study and multiple race information for subjects, must be considered in interpreting the results. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov, NCT00112008.