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Sunburn
Published in Charles Theisler, Adjuvant Medical Care, 2023
Selenium (plus copper) and a vitamin complex (with tocopherol and retinal) were examined for their ability to prevent sun burn cell formation in human skin. After three weeks of oral supplementation, there was relative protection (versus a placebo) against ultraviolet-induced cell damage. Supplementation was ineffective in preventing light-induced skin redness (erythema).4
Selected topics
Published in Henry J. Woodford, Essential Geriatrics, 2022
The pathogenesis has been subdivided into four stages (see the following) but progression of the lesions does not always follow this linear pattern. Skin redness can be harder to detect on people with darker skin, so extra vigilance is required.Stage 1: Superficial skin changes (e.g. non-blanching erythema, bogginess, increased temperature)Stage 2: Shallow ulcer due to loss of epidermis and/or dermisStage 3: Full thickness skin loss with necrosis of subcutaneous fatStage 4: Involvement of bone, tendon or muscle beneath the ulcer
Skin Color
Published in Enzo Berardesca, Peter Elsner, Klaus-P. Wilhelm, Howard I. Maibach, Bioengineering of the Skin: Methods and Instrumentation, 2020
Inflammatory skin erythema is the result of an increased presence of erythrocytes in skin structures. In inflammation cutaneous vessels are dilated and blood flow is increased. Because oxyhemoglobin has absorption in the spectral range of 520 to 580 nm, it absorbs green light, while red light is reflected to the observer. Changes in skin redness will affect the absorption of green light, but will very little affect that of red light. An erythema index of the skin can therefore be based on the ratio between the reflection of red and green light (Figure 3). Diffey et al.1 proposed an erythema index:
Remote investigation and assessment of vital signs (RIA-VS)—proof of concept for contactless estimation of blood pressure, pulse, respiratory rate, and oxygen saturation in patients with suspicion of COVID-19
Published in Infectious Diseases, 2022
Stefan Malmberg, Taha Khan, Ronny Gunnarsson, Gunnar Jacobsson, Pär-Daniel Sundvall
Heart rate per minute was computed by counting the number of peaks in the PPG signal normalized over 60 s. The respiration rate was estimated by enveloping the PPG signal. The idea was that during the inhalation of air, the increased level of blood oxygen increases skin redness. When the air is exhaled, the de-oxygenated blood reduces the redness. This increasing and decreasing trend in hue values of the PPG signal was used to encapsulate breathing cycles. The encapsulation was done by computing the upper and lower envelopes in the PPG signal using spline interpolation. Once the upper and lower envelopes are constructed, a peak finder algorithm is used to find the location of peaks in the lower envelope and the location of valleys in the upper envelope. A distance threshold was used between the location of peaks in the lower envelope and the location of valleys in the upper envelope to mark the boundary of a breathing cycle. The total number of envelopes in the signal was counted and normalized over 60 s to estimate the respiration rate over a minute.
MRGPRX2 is critical for clozapine induced pseudo-allergic reactions
Published in Immunopharmacology and Immunotoxicology, 2021
Di Wei, Tian Hu, Ya-jing Hou, Xiang-jun Wang, Jia-yu Lu, Shuai Ge, Cheng Wang, Huai-zhen He
Pseudo-allergic reaction is a non-immune-mediated allergic reaction. Different from the traditional allergic reactions, pseudo-allergic reactions can be induced directly by the antigen stimulating mast cells or basophils for the first time [8,9]. Activated mast cells or basophils could degranulation and release histamine [10–13]. The released histamine then activates the histamine H1 receptor, which expressed on multiple cell types such as smooth muscle cells and endothelial cells, causing vasodilation and increased vascular permeability [14–16]. These changes might eventually lead to local skin redness, swelling, itching, and other symptoms [17]. Therefore, these cutaneous symptoms can be used as the land markers for allergic reactions. The human G-protein-coupled receptor MRGPRX2 was confirmed as one of crucial receptors for the activation of mast cells in pseudo-allergic reaction [18]. Meanwhile, several researchers found that some small molecule drugs, such as morphine, sulfamethoxazole, mivacurium, could activate mast cells via MRGPRX2 in a dose-dependent manner [19,20]. The study on MRGPRX2 may provide a potential therapeutic target for drug-induced allergic reactions.
The effects of Antimicrobial Peptides and Hyaluronic Acid compound mask on wound healing after ablative fractional Carbon Dioxide laser resurfacing
Published in Journal of Cosmetic and Laser Therapy, 2019
Jia-an Zhang, Juan Liu, Hong-jin Wu, Yang Xu, Chen-cheng Si, Bing-rong Zhou, Dan Luo
The intensity of skin redness was measured using the erythema index (EI). Our study showed the average value of EI decreased continuously after achieving the peak value on day 1. The AMPs and HA compound mask-treated skin showed a significantly lower EI than that of untreated skin on day 1 (P < 0.05) (Figure 3a). The melanin index (MI) represents the skin darkening. Similar to the tendency of EI, the average value of MI reached its peak on day 1 and then decreased gradually until day 7 and increase slightly in the end of the study. The AMPs and HA compound mask side had a lower average value of MI, and the difference was statistically significant on days 1 and 3 (P < 0.05). Interestingly, the MI value was significantly higher in mask-treated skin than that of untreated skin on day 1. However, the MI value decreased gradually in the following days and showed a significantly lower MI value than that of untreated skin on day 3 (P < 0.05) (Figure 3b).