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Background Skin appearance is influenced by biophysical parameters. Seasonal changes affect the condition of normal skin and may trigger cutaneous disorders. Objectives This study was undertaken to measure the effects of seasonal changes on biophysical parameters in the skin of female subjects living in Guangzhou City in southern China. Methods A cross-sectional study was conducted in 178 healthy, adult Chinese women in whom forehead skin was examined in all four seasons between March 2007 and February 2008. Commercially available, non-invasive devices were used to measure skin hydration, sebum content, pH, and transepidermal water loss (TEWL) in a closed environment under controlled and constant conditions of temperature and humidity. Correlations between skin parameters and climate conditions were investigated. Results There were significant seasonal changes in TEWL and pH (autumn and winter > spring and summer), skin hydration (spring and summer > autumn and winter), and sebum content (spring and summer > autumn and winter). Skin hydration was correlated with average temperature and humidity. Skin TEWL and skin pH were correlated with average temperature, humidity, and ultraviolet (UV) radiation levels. Skin sebum content was correlated with average humidity. Conclusions Facial skin physiology showed seasonal variations in China. The reasons for the changes may refer to seasonal changes in temperature, humidity, and UV radiation.

Cathepsin B plays an important role in cell cycle, extracellular matrix changes and cutaneous tumorigenesis: whether it plays a role in photoaged skin remains unknown. This study aimed to investigate the role of cathepsin B in skin photoaging in vivo and in vitro.The expressions of cathepsin B were compared with immunohistochemical methods in solar exposed skin and solar protected skin of six healthy Chinese volunteers. The mRNA and protein expression of cathepsin B in ultraviolet light A (UVA) induced premature senescence fibroblasts in vitro were detected by real-time reverse transcription polymerase chain reaction (RT-PCR) and Western blotting technique.Decreased expression of cathepsin B was observed in photoaged skin compared with that of the solar protected skin. In the UVA induced, premature senescence fibroblasts, a lower expression of cathepsin B was detected by Western blotting and a decreased synthesis of cathepsin B mRNA in the same cells was revealed by real-time RT-PCR.The results demonstrated a significant negative correlation between skin photoaging and cathepsin B in vitro and in vivo. We propose that cathepsin B, besides matrix metalloproteinases and antioxidant enzymes, is involved in the process of skin photoaging in that it contributes to extracellular matrix remodelling and is a dominant protease in cellular apoptosis and senescence.

To observe the long-term toxicity of rats which we had applied Solanum lyratum Thunb gel on their skins daily for 90 days.We had applied high and low doses of Solanum lyratum Thunb gel one time each day on healthy and punctured rats skins respectively for 90 days. The rats' characters were observed, and their blood routines, blood biochemistry index, anatomic and pathologic changes of their major organs were also detected.Rats' characters had no change, the results of all detections were normal. There was no significant difference between test groups and control group. Rats'major organs had no change in anatomy and pathology.No long-term toxic reaction can be found in the test of rats applied Solanum lyratum Thunb gel on their skins for a long term. It proves that it is safe using the normal dose of this gel on the skin in clinic.

About 3%-10% of condyloma acuminatum (CA) may develop into cancer. Some studies indicated that homologous deletion of p16 gene is a major factor that causes cancerization of CA. This study was to detect expression of P16 protein in CA tissues and its cancerization tissues, and to investigate relationship of abnormal expression of P16 and cancerization of CA.A total of 75 skin biopsy specimens were collected, including 30 normal skin samples (control group), 35 CA samples, and 10 cancerized CA samples. Expression of P16 was tested by LSAB immunohistochemistry, and relationship of P16 and cancerization of CA was statistically analyzed.CA and normal skin tissues showed weakly positive expression of P16, no significant difference exist (P0.05). Cancerized CA tissues showed positive or strongly positive expression of P16, significantly stronger than CA and normal skin tissues (P0.05).Positive and strongly positive expression of P16 in CA tissue implied risk of cancerization of CA. P16 may be a useful predictor for cancerization of CA.