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Publications (6)18.82 Total impact

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    ABSTRACT: Retinol, a precursor of retinoic acid, has great potentials as a topical anti-aging molecule; however, only a handful of clinical investigations have been published to date. This study aimed to assess the efficacy and safety of 0.1% stabilized retinol on photodamaged skin during a one-year treatment. The investigation included two 52-week, double-blind, vehicle-controlled studies. In the main study, 62 subjects applied either a stabilized retinol formulation or its vehicle to the full face. A second exploratory study evaluated histological/histochemical markers in 12 subjects after 52 weeks of either retinol or vehicle use on contralateral dorsal forearms. The retinol group showed significant photodamage improvement over vehicle at all timepoints during the study. After 52 weeks, retinol had improved crow's feet fine lines by 44%, and mottled pigmentation by 84%, with over 50% of subjects showing +2 grades of improvement in many parameters. Additionally, at week 52, histochemical data confirmed the clinical results, showing increased expression of type I procollagen, hyaluronan, and Ki67 as compared to vehicle This study confirms that a stabilized retinol (0.1%) formulation can significantly improve the signs of photoaging, and improvements in photodamage continue with prolonged use. J Drugs Dermatol . 2015;14(3):271-276.
    No preview · Article · Mar 2015 · Journal of drugs in dermatology: JDD
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    Manpreet Randhawa · Vineet Sangar · Samantha Tucker-Samaras · Michael Southall
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    ABSTRACT: Skin chronically exposed to sun results in phenotypic changes referred as photoaging. This aspect of aging has been studied extensively through genomic and proteomic tools. Metabolites, the end product are generated as a result of biochemical reactions are often studied as a culmination of complex interplay of gene and protein expression. In this study, we focused exclusively on the metabolome to study effects from sun-exposed and sun-protected skin sites from 25 human subjects. We generated a highly accurate metabolomic signature for the skin that is exposed to sun. Biochemical pathway analysis from this data set showed that sun-exposed skin resides under high oxidative stress and the chains of reactions to produce these metabolites are inclined toward catabolism rather than anabolism. These catabolic activities persuade the skin cells to generate metabolites through the salvage pathway instead of de novo synthesis pathways. Metabolomic profile suggests catabolic pathways and reactive oxygen species operate in a feed forward fashion to alter the biology of sun exposed skin.
    Full-text · Article · Mar 2014 · PLoS ONE
  • Manpreet Randhawa · Samantha Tucker-Samaras

    No preview · Conference Paper · Apr 2013
  • Samantha Tucker-Samaras · Tara Zedayko · Curtis Cole · Dara Miller · Warren Wallo · James J Leyden
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    ABSTRACT: Retinol is a cosmetic ingredient that is structurally similar to all-trans-retinoic acid, which has been shown to be effective in the treatment of photodamage. Since skin keratinocytes are reported to metabolize retinol to retinoic acid, investigators have hypothesized that retinol may also be helpful in improving skin photodamage. In this eight-week, double-blind, split-face, randomized clinical study, a stabilized 0.1% retinol-containing moisturizer was tested (36 subjects) against the vehicle (28 subjects) in women with moderate facial photodamage. Each product was applied once daily to the designated half side of the face. Subjects were evaluated at baseline and after four and eight weeks of treatment using a 0-9 scale for photoaging parameters. The results showed that, after eight weeks, the retinol moisturizer was significantly more efficacious than the vehicle in improving lines and wrinkles, pigmentation, elasticity, firmness and overall photodamage. Many of these differences were significant at week 4, with a progressive improvement to week 8. This study demonstrates that a formulation containing stabilized retinol is safe and effective to ameliorate the appearance of photoaged skin.
    No preview · Article · Oct 2009 · Journal of drugs in dermatology: JDD
  • Tara Zedayko · claude saliou · curtis cole · samantha tucker-samaras · warren wallo
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    ABSTRACT: The volume of antiaging treatments available to patients continues to grow, and now more investigators are completing placebo-controlled, scientific clinical studies to verify their clinical benefits. The use of topical retinoids to reduce the signs of skin aging is well documented, and it has been shown that stabilized retinol diminishes many of these markers. In vitro studies have shown that retinol effects stimulation of collagen synthesis, reduction of matrix metalloproteinase levels, and induction of fibroblasts outgrowth. Also, long-term application of retinol at 0.04% in the upper arms reduced fine lines and provoked an accumulation of collagen in the papillary dermis. A double-blind, placebo-controlled, split-face study was conducted with an independent dermatologist to compare the ability of two different skin care technologies to deliver cutaneous benefits to photodamaged skin. A formulation containing 0.1% stabilized Retinol was compared with a formulation containing a glucosamine complex, and a placebo formulation containing no specific antiaging technology. Subjects were randomly assigned to two different formulas, and used the formulas once a day in the morning, over an 8-week period. Comparisons of the retinol formulation versus placebo and versus the glucosamine complex formulation included dermatologist assessment of fine and coarse wrinkling parameters, pigmentation parameters, firmness, and laxity parameters. By 4 weeks, improvement of the sites treated with retinol was statistically greater (P\.05) compared to both placebo and the glucosamine complex for fine lines and wrinkles, both on the cheeks and around the eyes, with higher significance by week 8. The retinol formulation also showed statistical superiority at 4 weeks for improvement of mottled and discrete pigmentation, as well as increased firming, all of which increased in significance by week 8. In this clinical study, a formulation containing retinol showed overall superior efficacy compared to a formulation containing a glucosamine complex for the treatment of the appearance of mild to moderate skin aging and photodamage.
    No preview · Conference Paper · Mar 2009
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    ABSTRACT: Antisense-based screening strategies can be used to sensitize a microorganism and selectively detect inhibitors against a particular cellular target of interest. A strain of Staphylococcus aureus that generates an antisense RNA against SecA,a central member of the protein secretion machinery, has been used to screen for novel antibacterials. Possible inhibitors of the SecA ATP-ase were selected with a high-throughput, two-plate agar-based whole cell differential sensitivity screen. After screening a library of over 115 000 natural products extracts with the SecA antisense strain, an extract of Geomyces pannorum was identified as providing increased activity against the sensitized strain as compared with the wild-type control. Bioassay-guided isolation of the active component from this fungal extract provided a new cis-decalin secondary metabolite, which we have named pannomycin.
    No preview · Article · Jan 2009 · Journal of Natural Products