Background There is a rationale for adding systemic photoprotective agents to the current photoprotection regimen. Objective This study was designed to objectively evaluate the molecular and ...photobiologic effects of oral administration of Polypodium leucotomos extract (PLE). Methods In all, 22 subjects with Fitzpatrick skin phototype I to III were enrolled. On day 1, subjects were irradiated with visible light, ultraviolet (UV) A1, and UVB (using 308-nm excimer laser). Evaluation was done immediately and 24 hours after irradiation. On days 3 and 4, irradiation and evaluation process was repeated after ingestion of PLE. Results Clinical assessments and colorimetry data showed a decrease in UVB-induced changes in 17 of 22 subjects post-PLE administration; histology findings demonstrated such a decrease in all 22 subjects. Limitations Only 2 doses of PLE were given. Furthermore, subjects with skin phototypes I to III only were studied. Conclusion The results suggest that PLE can potentially be used as an adjunctive agent to lessen the negative photobiologic effects of UVB.
Photosensitive conditions such as melasma and postinflammatory hyperpigmentation (PIH) are exacerbated by exposure to ultraviolet (UV) rays and visible light making sunscreen use an essential ...component of treatment. This is especially true in skin of color patients who are less likely to use photoprotection, even if diagnosed with these photoexacerbated conditions. We aimed to evaluate the body of literature to provide evidence for the use of sunscreen in the treatment of melasma and PIH. We reviewed English articles from PubMed, Journals@Ovid Full Text, and Embase using the search terms "sunscreen" and either "melasma" "PIH," or "post-inflammatory hyperpigmentation." Nine relevant publications provide evidence that a broad spectrum of protection, including UVA, UVB, and visible light within sunscreens can play an adjuvant role in therapy for melasma and PIH by stabilizing and improving these pigmentary disorders in skin of color patients. This review illustrates the advantages and limitations of sunscreen use, as well as practice gaps in photoprotection in the skin of color patients with melasma and PIH.
We used gold nanoparticles (NPs) to investigate the length-scale-dependent dynamics in semidilute poly(ethylene glycol) (PEG)–water solutions. Fluctuation correlation spectroscopy was used to measure ...the diffusion coefficients (D) of the NPs as a function of their radius (R 0), PEG volume fraction (ϕ), and molecular weight (M w). Our results indicate that the radius of gyration, R g, of polymer chain is the crossover length scale for the NPs experiencing nanoviscosity or macroviscosity. The reduced diffusivity can be plotted on a single master curve as D 0/D = exp(α(R 0/ξ)δ) for R g > R 0 and as D 0/D = exp(α(R g/ξ)δ) for R g ≤ R 0, where D 0 is the diffusion coefficient in neat solvent, ξ is the correlation length, α = 1.63, and δ = 0.89. In size regime, ξ < R 0 < a(ϕ), where a(ϕ) is the tube diameter for entangled polymer liquid, we found D ∼ ϕ–1.45 and independent of M w. For R 0 > a(ϕ), D ∼ ϕ–4 was obtained.
Visible light (VL) has been shown to promote genotoxicity through free radical generation and structural protein degradation. These stressful events promote cellular vulnerability, which manifests ...clinically as erythema, hyperpigmentation, and photoaging. Having established biologic impacts of VL, development of photoprotection strategies against this part of the solar spectra are warranted. This invited review presents advances in the VL literature and discusses available and potential means of VL photoprotection.
Excess amounts of skin surface oil can lead to adverse psychological consequences. Grease-spot photometry-based techniques measure sebum production rate. However, besides being tedious, these ...measurements are influenced by contact area, applied pressure, and time of application. Image analysis of polarized images has the potential to provide objective, quantitative information of skin oiliness. This study was designed to set up an imaging device for capturing and enhancing the changes in skin surface oiliness and to clinically and quantitatively, (via image analysis), evaluate varying levels of skin surface oiliness. Mineral oil was used to simulate skin surface oil. 40.5 µL of the mineral oil was applied within a two inch square area of interest on facial skin in twelve steps, from 1 to 40.5 µL, at 40% increments. The results indicate a strong correlation between the quantitative skin surface oiliness measurements and the clinical assessments. This sensitive technique has the potential to be utilized in future studies to evaluate product efficacies in reducing skin oiliness.
Postinflammatory hyperpigmentation (PIH) occurs following cutaneous injury and is common following resolution of acne especially in patients with skin of color. The objective of this study was to ...further validate a trichloroacetic acid (TCA)-induced PIH model and compare it to acne-induced PIH using topical bakuchiol, a botanical extract that has been shown to have antimicrobial, anti-inflammatory, antioxidant, and antiacne properties. A prospective, non-randomized clinical trial was conducted on subjects with skin phototypes IV–VI with a history of acne-induced PIH. Subjects applied bakuchiol or vehicle cream twice daily to 2 acne-induced and 2 TCA-induced PIH lesions for 28 days with a third lesion serving as a control in each group. Degree of improvement was defined as the change in the Investigator Global Assessment (IGA) score over 28 days of treatment. Twenty subjects (6 males, 14 females) completed the study. For TCA-induced PIH sites, there was a statistically significant (
p
< 0.05) degree of improvement with bakuchiol treatment (− 0.50 ± 0.18) compared to vehicle (0.05 ± 0.15) and control (− 0.06 ± 0.17). For acne-induced PIH, there was a greater degree of improvement for bakuchiol (− 1.06 ± 0.23) when compared to vehicle (− 0.56 ± 0.16) and control (− 0.69 ± 0.18); however, statistical significance was not reached (
p
> 0.05). TCA-induced PIH sites were uniform in size and pigment intensity thereby allowing better comparison among sites. This emphasizes the relevance of using this model for PIH which may help reduce the barriers in clinical trials and help improve access to treatments for patients who suffer from PIH. The results suggest that topical bakuchiol may decrease the severity of PIH.
Postinflammatory hyperpigmentation: A comprehensive overview Silpa-archa, Narumol; Kohli, Indermeet; Chaowattanapanit, Suteeraporn ...
Journal of the American Academy of Dermatology,
October 2017, 2017-10-00, Letnik:
77, Številka:
4
Journal Article
Recenzirano
Postinflammatory hyperpigmentation (PIH) commonly occurs after various endogenous and exogenous stimuli, especially in dark-skinned individuals. PIH is one of the most common complications of ...procedures performed using laser and other light sources. The severity of PIH is determined by the inherent skin color, degree and depth of inflammation, degree of dermoepidermal junction disruption, inflammatory conditions, and the stability of melanocytes, leading to epidermal and dermal melanin pigment deposition. The depth of melanin pigment is the key factor to predict prognosis and treatment outcome. Epidermal hyperpigmentation fades more rapidly than dermal hyperpigmentation. Various inflammatory disorders can eventually result in PIH. The evaluation of pigmentation using noninvasive tools helps define the level of pigmentation in the skin, pigmentation intensity, and guides therapeutic approaches. This first article in this 2-part series discusses the epidemiology, pathogenesis, etiology, clinical presentation, differential diagnoses, and investigation using noninvasive assessment techniques that objectively determine the details of pigmentation.
Postinflammatory hyperpigmentation: A comprehensive overview Chaowattanapanit, Suteeraporn; Silpa-archa, Narumol; Kohli, Indermeet ...
Journal of the American Academy of Dermatology,
October 2017, 2017-10-00, Letnik:
77, Številka:
4
Journal Article
Recenzirano
Postinflammatory hyperpigmentation (PIH) occurs after various dermatoses, exogenous stimuli, and dermatologic procedures. The clinical course of PIH is chronic and unpredictable, although the ...probability of resolution of epidermal hyperpigmentation is better than those of dermal hyperpigmentation. PIH can be prevented or alleviated. When it does occur, the underlying inflammatory conditions should be sought and treated as the first step to reduce the progression of inflammation and PIH (which is an inflammatory consequence). If the inflammatory conditions subsides or there is no evidence of inflammation at the time of diagnosis, the treatments of PIH should be considered as the next step. Understanding the available treatment options helps the physician choose the appropriate treatment for each patient. Having a reproducible model for PIH is essential for the development of treatment modalities. The second article in this 2-part continuing medical education series on PIH specifically addresses the evidence that supports medical and procedural treatments of PIH and other forms of acquired hyperpigmentation. It also describes a PIH model and provides an algorithm for clinical practice along with discussion about the prevention of PIH.
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