Objective To investigate the minimal erythema does (MED) of normal skin to UV in Guangzhou city,and to observe its relationship to sex,age,skin type,seasons and the years lived in Guangzhou.Methods 621 healthy subjects were exposed to Solar Simulator (GS2004) and the MED was measured and observed by two professional technicians after (24±2) hours.Results The average MED value of all subjects was (1170.2±333.2) mJ/cm2.In male and female group,the average MED values were (1132.8-339.4) mJ/cm2 and (1182.1 ± 330.7) mJ/cm2,respectively,and there was no significant difference between male and female (P=0.20).The MED value in subjects aged from 30 to 50 (1014.7 ± 359.7) mJ/cm2 was significantly lower than those aged from 20 to 29 (1222.9±304.3) mJ/cm2 and over 50 years (1179.0±374.3) mJ/cm2 (P＜0.01).The MED value in skin type Ⅱ (673.53±228.3) mJ/cm2 was significantly lower than those in type Ⅲ (1224.3±254.2) mJ/cm2 and Ⅳ(1363.1±278.5) mJ/cm2(P＜0.01).There was significant difference of the MED value between different seasons (P＜0.01).The MED value in spring (969.2±355.8) mJ/cm2 was lowest,and followed by summer (969.2± 355.8) mJ/cm2.However,there was no significant difference between autumn and winter (P＞0.05).The MED value in subjects lived in Guangzhou from 5 to 10 years was significantly lower than those whose residence time was from 1 to 4 years and over 10 years,respectively.Conclusions The MED value of the subjects in Guangzhou is quite different from other cities of China,and related to age,skin types,seasons and the years lived in Guangzhou city,while there is no correlation between MED value and gender difference.

Objective To investigate the minimal persistent pigment dose (MPPD)of normal skin to UVA in Guangzhou city,and to observe its relationship to sex,age,skin type,seasons,ITA,and the years lived in Guangzhou.Methods 316 healthy subjects were exposed to Solar 601-300,and the MPPD was measured and observed by two professional technicians after 2-3 hours.Results The average MPPD value of all subjects was (9.61±2.57) J/cm2.In male and female,the average MPPD values were (11.09 ± 2.82) J/cm2 and (9.01 ± 2.20) J/cm2 respectively,and male was significantly higher than female (P＜0.01).There was significant difference of the MPPD value in different seasons (P＜0.01).The MPPD value in winter (10.66± 2.71) J/cm2) was significantly higher than spring (9.37±2.39) J/cm2,summer (9.53±2.66) J/cm2 and autumn (8.98±2.25) J/cm2.There was significant difference of the MPPD value between different ITA groups (P＜0.01).ITA grade-3 (10.72± 2.84) J/cm2 was significantly higher than grade-1 (8.50±1.45) J/cm2 and grade-2 (9.12±2.31) J/cm2 (P＜0.01),but there was no significant difference from grade-4 (11.87±2.73) J/cm2 (P =0.93).The MPPD value in subjects lived in Guangzhou over 10 years (8.97± 1.88) J/cm2 was significantly lower than those whose residence was less than 1 year and from 1 to 5 years,respectively (P＜0.01),but there was no significant difference from those lived from 5 to 10 years (P =0.47).Conclusions The MPPD value of the subjects in Guangzhou is related to gender,seasons,ITA grade and the years lived in Guangzhou city,while there is no correlation with age and skin types.

Objective To evaluate the performance of transfection with a complex plasmid encoding green fluorescent protein tagged CatD (GFP-CatD)in researches on chronic photodamaged fibroblasts. Methods Human dermal fibroblasts (HSFs)were irradiated with ultraviolet A (UVA)at 25 J/cm2 once a day for 21 consecutive days to establish a chronic photodamaged cell model. A plasmid encoding GFP-CatD was constructed and transfected into some chronic photodamaged fibroblasts (experimental group). The photodamaged HSFs receiving no treatment served as the blank control group, and those transfected with the negative plasmid encoding GFP only as the negative control group. After additional culture, fluorescence microscopy and Western-blot analysis were performed to observe and measure the expression of GFP-CatD in HSFs respectively, flow cytometry and methyl thiazolyl tetrazolium (MTT)assay to evaluate the apoptosis and proliferation of chronic photodamaged fibroblasts respectively. Results Fluorescence microscopy showed the expression of GFP-CatD in cytoplasm of chronic photodamaged fibroblasts at 96 hours after transfection with the GFP-CatD-encoding plasmid. Western-blot analysis revealed that the expression of CatD in the experimental group was 1.28 times that in the blank control group. There were no significant differences in the apoptosis rate(4.29% ± 1.30%vs. 3.03% ± 1.70% , P > 0.05)or proliferative rate (45.20% ± 4.70% vs. 43.60 ± 3.90% , P > 0.05)between the experimental group and blank control group. Conclusion CatD could be traced in chronic photodamaged fibroblasts with no changes in biological activity or cell cycle after transfection with the GFP-CatD-encoding complex plasmid.

Objective:To evaluate the efficacy and safety of Hymagic-4D multi-essence (miniHA, acetylated sodium hyaluronate, sodium hyaluronate, sodium hyaluronate cross-linked polymer) on sensitive skin.Methods:The clinical trial was conducted from April 2, 2019 to April 30, 2019 in the Cosmetic Dermatology Laboratory of the Third Affiliated Hospital of Sun Yat-Sen University. A total of 33 subjects (average age of 43±9.5) completed the trial. Subjects diagnosed as sensitive skin according to the criteria were enrolled. Hymagic-4D were randomly applied on one side of the face while macromolecular hyaluronic acid was applied on opposite side for 28 days. Skin biophysical properties, lactic test, clinical efficacy and safety were evaluated by the investigators at day 0, day 7, day 14 and day 28. Skin water content, TEWL and a*value were measured at the same time.Results:Dates showed that at day 7, day 14 and day 28, the a* values on Hymagy-4D using side were 8.54±3.08, 8.87 ±3.21 and 8.39±3.21, lower than that on the side of control 9.48±3.09, 9.51±3.30 and 9.03±2.95 ( P<0.01); skin roughness score, dryness score and erythema score on hymagy-4d using side were significantly lower than before ( P<0.01), and significantly lower than that on the control side ( P<0.01). Hydration, TEWL, pH value, L value and total score of lactic acid tingling test which were significantly improved on both facial skin compared to the baseline ( P<0.05) showed no statistical difference between two facial sides ( P>0.05) during 28-day treatment. Conclusions:This study demonstrates that Hymagic-4D has more effective in repairing skin barrier and inhibiting skin inflammation than single component hyaluronic acid on sensitive skin persons.