Objective To estimate the value of clinical parameters (such as patients' age,longitudinal melanonychia width and location) for the differential diagnosis of malignant and benign longitudinal melanonychia as well as for the evaluation of the necessity for invasive management.Methods A retrospective study was performed on 28 cases of subungual malignant melanoma collected from 2000 to 2010 as well as on 62 cases of benign longitudinal melanonychia from 2005 to 2010.Clinical analysis was carried out to compare the differences in clinical parameters such as.patients' age,longitudinal melanonychia width and lesional location,between the malignant melanoma and benign longitudinal melanonychia cases.Logistic regression analysis and ROC method were used to determine valuable clinical parameters for the differential diagnosis of malignant and benign longitudinal melanonychia.Results Significant differences were observed in the median age at diagnosis (23.0 years vs.52.5 years,Z =5.44,P ＜ 0.01 ),age at onset (21.0 years vs.48.0 years,Z =4.70,P ＜ 0.01 ),and longitudinal melanonychia width (3.0 mm vs.15.0 mm,Z =5.69,P ＜ 0.01 ) between the patients with malignant melanoma and benign longitudinal melanonychia.The involvement of thumb and hallux was observed in 77.8％ of the subungual melanoma cases,and 48.3％ of the benign cases (x2 =6.57,P ＜ 0.05).ROC method and Logistic regression analysis indicated that the age at onset and diagnosis as well as width of longitudinal melanonychia were of diagnostic value for the differential diagnosis of malignant and benign longitudinal melanonychia.Conclusions Not all longitudinal melanonychia cases need an invasive management at the time of awareness.The age at onset and diagnosis,width of melanonychia and site of the onset appear to be valuable in the differential diagnosis of malignant and benign longitudinal melanonychia,and there is a possibility to guide clinical diagnosis and treatment by establishing a mathematical model with these parameters.

Medical ethics education in clinical practice stage is especially critical to improve medical students' humanistic, medical ethics and professional accomplishment. Compared with other clinical disciplines, dermatology and venereology has many characteristics. To strengthen medical ethics education in dermatology and venereology clinical practice, we should persist in promoting and cultivating core values of Chinese socialism, accurately grasp the characteristics of various skin diseases, educate and guide students to flexibly apply the basic principles of ethics and improve their ethical decision-making ability. In the process of teaching implementation, we should pay attention to the coordination of education, enrich teaching means and strengthen practical teaching, so as to improve the quality of education.

Objective To explore and establish a method for quantitative evaluation of facial skin pores based on dermoscopy,and to evaluate the scientificity and practicability of this method.Methods Totally,30 patients with enlarged facial skin pores were enrolled from Department of Dermatology,Peking University Third Hospital between June 2017 and December 2017,and treated with 2 940 nm Er pixel laser.Photographs were taken,and dermoscopic images were collected before and after treatment.According to the standard photographs of facial pores,the improvement of enlarged facial pores was evaluated by comparing the photos before and after the treatment.A dermoscope-based pore detection system was established,and quantified indices for pore area and color difference before and after the treatment were evaluated by using this system.A pre-post self-contrast study was conducted,and statistical analysis was carried out by using paired t test for the comparison of measurement data and paired non-parametric test (Wilcoxon signed-rank test) for the comparison of ranked data.Results After the treatment,the standard photograph method for the assessment of facial pores showed score reduction by 3 grades in 1 of the 30 patients (3.3％),by 2 grades in 7(23.3％),by 1 grade in 21(70％),and no changes of grades in 1 (3.3％).Additionally,the differences between pre-and post-treatment grades were significant (Z =-4.94,P ＜ 0.01).The detection rate of skin pores by using the detection system was (70.59 ± 3)％.After the treatment,the quantified values of pore area and color difference both significantly decreased compared with those before the treatment (pore area:712.95 ± 87.45 vs.831.45 ± 88.92,t =5.70,P ＜ 0.05;color difference:23.82 ± 9.43 vs.28.92 ± 9.91,t =2.76,P ＜ 0.05).Conclusion The dermoscopy-based method for quantitative evaluation of skin pores after the treatment with 2 940 nm Er pixel laser showed highly consistent results with the standard photograph method,which can be further verified and popularized in the evaluation of enlarged skin pores.

Objective:To investigate characteristics and changes of skin microbiota in atopic dermatitis-like mouse models induced by different concentrations of 2,4-dinitrochlorobenzene (DNCB) .Methods:Totally, 30 male specific-pathogen-free BALB/c mice were randomly divided into 3 groups by using a random number table: negative control group topically treated with 200 μl of mixture of acetone and olive oil at a volume ratio of 3∶1 on the back twice a week for 6 consecutive weeks; high-and low-concentration DNCB groups both topically treated with 200 μl of 1% DNCB on the first and third day at the first week, followed by topical application of 200 μl of 0.5% and 0.1% DNCB, respectively, twice a week for 5 weeks from the second week. Twenty-four hours after the last treatment, the severity of skin lesions was evaluated, and the transepidermal water loss and stratum corneum hydration were measured. After the experiment, the mice were sacrificed, and skin tissues were resected from the back of the mice for histopathological examination. Full-thickness skin tissue samples were obtained from the back of 3 mice in each group. Illumina Miseq PE300 high-throughput sequencing was performed to sequence the V3-V4 variable region of 16S rRNA gene of skin microbiota on the back of the mice, and the composition and structure of the skin microbiota and changes in the relative abundance of different genera were analyzed. One-way analysis of variance was used to analyze differences in indices among the 3 groups, and the Games-Howell method was used for multiple comparisons.Results:The severity scores of skin lesions were significantly higher in the high-and low-concentration DNCB groups (9.83 ± 2.45 points, 2.71 ± 0.56 points, respectively) than in the negative control group (0.51 ± 0.12 points, t=-7.19,-2.85, respectively, both P < 0.05) . Compared with the negative control group, the high-and low-concentration DNCB groups showed significantly increased transepidermal water loss ( t=-7.72,-2.68, respectively, both P < 0.05) , but significantly decreased stratum corneum hydration ( t=6.77, 5.99, respectively, both P < 0.05) ; the transepidermal water loss was significantly higher in the high-concentration DNCB group than in the low-concentration DNCB group ( t=2.76, P < 0.05) , while no significant difference in the stratum corneum hydration was observed between the high-and low-concentration DNCB groups ( P > 0.05) . There was a significant difference in the relative abundance of Corynebacterium among the 3 groups ( F=249.85, P < 0.001) , which was highest in the high-concentration DNCB group. No significant differences in the observed species and Chao1 index of the skin samples were observed among the 3 groups (both P > 0.05) , and the Shannon index was significantly lower in the high-concentration DNCB group than in the low-concentration DNCB group and negative control group ( t=6.96,-6.37, respectively, both P < 0.05) . Conclusion:DNCB could induce atopic dermatitis-like dermatitis in mice, and the severity of skin lesions and degree of barrier function impairment were related to the concentration of DNCB; the species diversity of skin microbiota markedly decreased in the high-concentration DNCB group, indicating that high-concentration DNCB modeling has more advantages in studying microbiological changes associated with atopic dermatitis.

Strengthening medical ethics education for medical students is the need for the healthy development of human medical health, the cultivation of medical students’ professional ethics and the integration of medical ethics spirit and medical ethics practice. Through in-depth discussion of the new mode of the integration of medical ethics education and medical ethics practice, stimulating the new impetus of the integration of medical students’ self-cultivation into practice, and the new ways to cultivate the growth of medical students in the new era, this paper put forward specific measures to create an education suitable for each student’s development by selecting the medical ethics education team, learning ethics and humanistic education, taking medical students as the center, and creating a suitable learning environment for students, with a view to cultivating medical students to grow into guardians who can cope with the challenges of public health emergencies.