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.

A 38-year-old woman presented with a 20-year history of yellow papules and band-like atrophy on the right neck. The lesions developed slowly and were asymptomatic. There was no history of long-term sun exposure or family history of similar diseases. Skin examination revealed multiple irregularly sized yellow papules and plaques on the right anterior neck following cleavage lines, multiple pin cap-sized perifollicular papules on the posterior right neck. Well-defined band-like atrophic patches with fine wrinkling were observed in the whole right neck, giving an aged appearance. The skin of the left neck was nearly normal. Pathological examination of biopsy specimens from the yellow papules showed a normal epidermis, scant lymphohistiocytic and melanophage infiltrates around the vessels in the superficial dermis without solar degradation. The collagen bundles in the mid dermis were slightly thickened and arranged tightly in parallel to the skin surface with the absence of inflammatory infiltrate. Verhoeff-van Giesen's staining confirmed a nearly complete absence of elastic fibers in the mid dermis as well as obvious swelling and breakage of resident scant elastic fibers. Von Kossa's staining was negative. Based on the above findings, the diagnosis was made as unilateral mid-dermal elastolysis.

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 analyze changes in sensitivity of clinical strains of Ureaplasma urealyticum (Uu) to 9 kinds of common antibiotics from 2017 to 2018. Methods: The results of drug sensitivity testing of clinical Uu strains, which were isolated from 19 431 patients in Laboratory of Sexually Transmitted Disease (STD) , Department of Dermatology and Venereology, The Third Affiliated Hospital, Sun Yat-Sen University from 2007 to 2018, were analyzed retrospectively. Of the 19 431 patients, 6 076 were males, and 13 355 were females. Their age ranged from 15 to 68 years. The tested antibiotics included minocycline, doxycycline, erythromycin, azithromycin, clarithromycin, roxithromycin, ciprofloxacin, sparfloxacin and levofloxacin. Results: Resistance rates of clinical Uu strains to minocycline and doxycycline gradually decreased from 10.08% and 10.42% in 2007 to 1.15% and 2.61% in 2018, respectively, while sensitivity rates to minocycline and doxycycline gradually increased from 85.88% and 87.56% in 2007 to 97.02% and 96.42% in 2018, respectively. The resistance rate and sensitivity rate of clinical Uu strains to erythromycin fluctuated greatly during 2014—2017, with the resistance rate fluctuating around 20%, and the sensitivity rate fluctuating around 50%. The resistance rate of clinical Uu strains to azithromycin dropped rapidly from 42.02% in 2007 to 8.39% in 2011, and then fluctuated slightly around 10%. However, the sensitivity rate to azithromycin increased from 8.40% in 2007 to 86.05% in2011, and remained above 80% from then on to 2018. During 2007—2018, Uu strains showed low resistance rates (10%-20%) and high sensitivity rates to clarithromycin (80%-90%) , and the resistance and sensitivity rates to roxithromycin were similar to those to erythromycin. Uu strains showed constantly high resistance to ciprofloxacin (more than 80% after 2013) and low sensitivity (persistently less than 10%) . The sensitivity rate of clinical Uu strains to sparfloxacin fluctuated around 40%, while the resistance rate was maintained below 10% after 2011. The resistance and sensitivity rates of Uu strains to levofloxacin were similar to sparfloxacin, but the sensitivity rate to levofloxacin was relatively lower, which had been maintained at about 30%. Conclusion From 2007 to 2018, clinical Uu strains maintained a relatively stable low resistance rate and a high sensitivity rate to minocycline, doxycycline and clarithromycin, a high resistance rate and low sensitivity rate to ciprofloxacin, and a low resistance rate and sensitivity rate to sparfloxacin and levofloxacin; a relatively stable low resistance rate and a high sensitivity rate to azithromycin were achieved only after 2011; the resistance rate and sensitivity rate to erythromycin and roxithromycin fluctuated greatly.