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Objective:To investigate differences in stratum corneum components between sensitive skin and normal skin by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, and to evaluate the value of ATR-FTIR spectroscopy in the study of pathogenesis of sensitive skin.Methods:From December 2018 to February 2019, 148 volunteers were recruited, who had lived in Shanghai for ≥ 6 years. Through questionnaire survey, lactic acid sting test and capsaicin test, the subjects were divided into normal skin group and sensitive skin group; meanwhile, total sting score and total burning score of the subjects were recorded in the lactic acid sting test and capsaicin test respectively. ATR-FTIR spectroscopy was performed to detect stratum corneum components, including natural moisturizing factor (NMF), stratum corneum lipids, free fatty acids (FFA) and β-sheet/α-helix (β/α) ratio; moreover, other non-invasive techniques were used to measure skin physiological parameters, including transepidermal water loss (TEWL), stratum corneum hydration (SCH) levels, stratum corneum lipids, skin pH, current perception thresholds of 3 peripheral sensory nerve fibers, and superficial skin blood flow perfusion. Spearman correlation coefficients between stratum corneum components and the total sting score as well as total burning pain score were analyzed, so were Pearson correlation coefficients between the stratum corneum components and skin physiological parameters.Results:A total of 73 volunteers completed all tests, including 15 males and 19 females aged 41.8 ± 8.9 years in the sensitive skin group, and 19 males and 20 females aged 42.8 ± 9.4 years in the normal skin group. Compared with the normal skin group, the sensitive skin group showed significantly decreased levels of stratum corneum NMF (30.90 ± 7.38 vs. 37.01 ± 8.77, t = 3.193, P < 0.01) and FFA (14.90 ± 6.75 vs. 20.45 ± 11.76, t = 2.422, P < 0.05), but significantly increased β/α ratio (3.17 ± 1.03 vs. 2.67 ± 0.56, t = -2.595, P < 0.05) ; there was no significant difference in stratum corneum lipid content between the two groups ( t = 1.458, P > 0.05). As far as the skin physiological parameters were concerned, the sensitive skin group showed significantly increased TEWL ( t = -3.496, P < 0.001), but significantly decreased current perception thresholds at a frequency of 5 Hz and epidermal density (both P < 0.05) compared with the normal skin group; no significant difference in stratum corneum lipid content was observed between the two groups ( P > 0.05). Correlation analysis revealed that NMF, FFA and β/α ratio were significantly correlated with TEWL ( r = -0.405, -0.562, 0.503, respectively, all P < 0.01) and total sting score ( rs = -0.401, -0.285, 0.316, respectively, P < 0.01 or 0.05) ; meanwhile, epidermal density was also significantly correlated with NMF ( r = 0.402, P < 0.01) and β/α ratio ( r = -0.369, P < 0.05). However, none of NMF, FFA and β/α ratio was correlated with stratum corneum lipid content, current perception thresholds of the 3 sensory nerve fibers, superficial skin blood flow perfusion or epidermal thickness (all P > 0.05) . Conclusions:NMF, FFA and β/α ratio in the stratum corneum significantly differed between the sensitive skin and normal skin, and were significantly correlated with some physiological parameters related to stratum corneum barrier function. ATR-FTIR spectroscopy is an effective method for evaluating barrier function of sensitive skin.
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Objective To investigate reflectance confocal microscopy (RCM) features of irritant cutaneous reactions to sodium lauryl sulphate (SLS) in healthy persons aged from 18 to 60 years,to analyze effects of age and gender on cutaneous reactions,and to estimate the value of RCM in objective evaluation of cutaneous reactions.Methods An occlusive patch test was performed on the back of 120 healthy testees with 0.1％ and 0.5％ SLS solution (0.1％ and 0.5％ SLS groups) and distilled water (negative control group) for 48 hours.At different time points after the patch removal,clinical evaluation and RCM were performed.Results RCM imaging in the 0.1％ and 0.5％ SLS groups showed parakeratosis,indistinct structure of the stratum corneum,spongiosis and infiltration of inflammatory cells in the epidermis,and telangiectasia in the papillary dermis.The incidence of RCM features reached the peak until 24 hours after the removal of 0.1％ and 0.5％ SLS patches,and the incidence of telangiectasia in the dermis was up to 66.7％ and 95.0％ in the 0.1％ and 0.5％ SLS groups respectively.At 24 hours after the removal of 0.5％ SLS patch,the incidence of spongiosis was significantly lower in the males than in the females (68.9％ [42/61] vs.84.7％ [50/59],x2 =4.24,P ＜ 0.05).However,the incidence of spongiosis was significantly higher in testees aged 18-40 years than in those aged 41-60 years at 24 hours after the removal of 0.1％ SLS patch (53.3％[32/60] vs.35.0％[21/60],x2 =4.09,P ＜ 0.05).For the other RCM features,there were no significant differences in their incidence between different genders or age groups after the removal of 0.1％ and 0.5％ SLS patches (all P ＞ 0.05).Clinical evaluation showed that after the removal of 0.1％ and 0.5％ SLS patches,no significant difference in the incidence of irritant cutaneous reactions was observed between the males and the females or between the testees aged 18-40 years and those aged 41-60 years (all P ＞ 0.05).There were good correlations between the clinical evaluation results and RCM features.At 24 hours after the removal of 0.1％ SLS patch,the correlation coefficient between spongiosis and clinical evaluation results was up to 0.77,so was that between telangiectasia in the dermis and clinical evaluation results (both P ＜ 0.001).However,at 0.5 hour after the removal of SLS patches,clinical evaluation showed that the positive reaction rates were 2.5％ (3/120) and 12.5％ (15/120) in the 0.1％ and 0.5％ SLS groups respectively.In the meantime,there were 17.5 ％ (21 / 120) and 51.7％ (62/120) of testees manifesting more than 2 RCM features in the 0.1％ and 0.5％ SLS groups respectively,which were more similar to the clinical evaluation results at 24 hours after the removal of SLS patches (34.2％ [41/120] and 85.0％ [102/120] in the 0.1％ and 0.5％ SLS groups respectively) compared with the clinical evaluation results at 0.5 hour after the removal of SLS patches.Conclusions Neither gender nor age affects irritant cutaneous reactions to 0.1％ and 0.5％ SLS.Compared with clinical evaluation,RCM can evaluate cutaneous reactions more objectively and accurately in the early stage of irritant reactions.
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Objective To explore differences in phototest and photopatch test results, and in skin color?related parameters between healthy subjects and patients with chronic actinic dermatitis (CAD), and to examine their relationship with the melanocortin?1 receptor gene(MC1R)Arg163Gln variant. Methods Phototests were performed by using a sun simulator SUN1000, and skin color was analyzed by using Hexameter MX18 in 25 patients with CAD and 25 healthy subjects. The MC1R genotype at position?163 was determined by PCR. Photopatch tests were performed on 25 patients with CAD and 5 healthy subjects using a standard series of photoallergens(RuiMin)and an ultraviolet (UV)phototherapy equipment, SS?03A. Results Regarding phototest results, both UVA?minimal persistent pigment darkening dose(MPPD)and UVB?minimal erythema dose(MED)were significantly lower in CAD patients compared with healthy controls (both P 0.05), but that of the CAA genotype differed significantly between the two groups(P<0.01). UVA?MPPD and UVB?MED were both significantly lower in CAD patients with the CAA genotype at position?163 in the MC1R gene than in those without the genotype(P=0.055, 0.325, respectively). Conclusions Skin photobiological testing plays a critical role in the diagnosis of CAD. Further studies are needed to clarify the role of the CAA genotype at position?163 in the MC1R gene in the diagnosis, prevention and treatment of CAD.
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Objective To explore the sample reIated factors affecting the short-term culture of erythrocytic Plasmodium dvax in vitro.Methods The vivax malaria blood samples were collected from the patients with malaria in endemic areas,and then incubated with McCoy's 5A medium in an incubator containing 5%CO_2 at 37℃.The factors affecting the short-term culture of Plasmodium vivax were analyzed.Results Plasmodium vivax could finish one asexual cycle in the selected medium.By analyzing the culture results of 74 samples.it was found that the factors affecting the short-term culture included long time delaying al room temperature(>4 h),single stage(only parasites in ring stage were found),patients taking antimalarials,antibiotics or sulfonamides.and low parasitemia.Conclusion The sample related factors are important to the short-term culture of erythrocytic Plasmodium vivax in vitro.