Hair follicle stem cells in dermis have multiple differentiation potential, and can differentiate into hair shaft, internal myelin sheath, external myelin sheath, skin epithelial keratinocytes and sebaceous glands. Hair follicle stem cells can maintain the cycle of hair follicle, but also plays an important role in epidermis wound healing. Studies on hair follicle cells participate in epidermal healing following wound are early, but studies on hair follicle stem cells appear recently. The signal pathways related may be Wnt, BMP, FGF, Notch, SHH and so on. In order to understanding the role of micro-wound healing in plastics and cosmetic medicine and skin issue-engineering, how hair follicle stem cells participate in epidermal healing and signaling pathways related were reviewed in this study.

Object To study the change of serum soluble interleukin 2 receptor(SIL-2R) in syphilitic patients and its clinical significance.Methods The serum SIL-2R level in syphilitic patients of different stages and after therapy were detected using the ELISA technique.Results The serum SIL-2R level in syphiliti patients was higher than that in control group(P0 05).Conclusions SIL-2R level and its variation have some reference value for evaluating the therapeutic effect and judgement of the disease course in syphilitic patients.

Objective To investigate the effects of photochemotherapy on the angiogenic ability of endothelial cells and expression of integrin. Methods In vitro angiogenesis assay ( UVA exposure dose: 0, 2.0, 5.0 J/cm~2) was used to detect the effects of photochemotherapy on the angiogenic ability of endothelial cells. Reverse polymerase chain reaction and flow cytometry were employed to determine the effects of photochemotherapy on the expression of integrin mRNA and protein, respectively. bFGF stimulation group and PMA stimulation group were divided according to the inductors, and subgroups were divided according to the UVA exposure doses of 0, 2. 0 and 5. 0 J/cm~2 in each group. Results Combination of UVA (2.0 and 5.0 J/cm~2) and 8-MOP (100 ng/mL) resulted in a decrease in the angiogenic ability of endothelial cells in vitro and the expression of integrin mRNA and protein. Conclusion Photochemotherapy may inhibit the angiogenic ability of endothelial cells through downregulating the expression of integrin.

Objective To investigate the histological changes of normal human skin after fixed irradiation with multiple-pulse fractional Er:YAG laser.Methods After hair removal,the upper arms of 7 healthy volunteers were consecutively irradiated with multiple-pulse fractional Er:YAG laser.Tissue samples were resected from the irradiated skin at 1,24,48,72 hours,on day 5,7,15,and 30 after the irradiation.Hematoxylin and eosin(HE)staining and Masson staining were performed to observe the histological changes and collagen proliferation respectively.Immunohistochemical staining was used to detect the expression of heat shock protein(HSP)70 and 47.Results The consecutive irradiation with multi-pulse fractional Er:YAG laser generated an array of tapering microscopic treatment zones(MTZs)of gasification and ablation in the upper arm skin.After the irradiation,inflammation developed in the microscopic lesions with the epithelization of epidermal cells within 7 days; local dermal collagen was renewed and remodelled during the 7th to 30th day.HSP70 expression peaked as early as 48 hours after the treatment and maintained until the 7th day,while the high expression of HSP47 persisted from the 15th to 30th day after irradiation.Conclusion The fixed,multiplepulse and fractional Er:YAG laser irradiation can reach the deep dermis,and induce the local proliferation of dermal collagen.

Objective To evaluate the effect of fractional Er:YAG laser therapy on collagen and elastic fibers in photoaged skin of ultraviolet-irradiated Guinea pigs.Methods Sixty Guinea pigs were randomly divided into the non-intervention group (n =10) and model group (n =50) by a random number table.To establish a model of photoaging,the 50 Guinea pigs were irradiated by ultraviolet A (UVA) and ultraviolet B (UVB) on the back every other day for two months.Subsequently,the 50 mice were equally classified into five groups:photoaging group receiving no laser therapy,as well as 2-week,4-week,8-week and 12-week group receiving one,one,two and three sessions of successive multi-pulsed fractional Er:YAG laser therapy,respectively,on the left side (treatment side) of the back,with the right side as the control side.The interval of laser therapy was four weeks.Skin biopsies were obtained from the right and left side of the back of Guinea pigs after the laser therapy,and subjected to haematoxylin and eosin (HE) staining,Masson staining and Weigert-van Gieson staining.The content of hydroxyproline was measured by using an alkaline-hydrolysis method.Results The minimal erythema dose for UVA and UVB was 4224 mJ/cm2 and 504 mJ/cm2 respectively on Guinea pig skin.The model for photoaging was successfully established in 50 Guinea pigs after two months of irradiation with the cumulative dose of UVA and UVB being 459.36 J/cm2 and 54.81 J/cm2 respectively.HE staining revealed an obvious increase in newly-growing collagen and elastic fibers,which were arranged densely,in the treatment side compared with the control side of the back of Guinea pigs after laser therapy.The area ratio of collagen fibers stained positive for Masson's trichrome and content of hydroxyproline were significantly higher in the treatment side than in the control side of the 12-week group (0.70 ± 0.12 vs.0.63 ± 0.08,t =1.18,P ＜ 0.05;(4.73 ± 0.39) mg/g vs.(3.66 ± 0.85) mg/g,t =3.40,P ＜ 0.05).Conclusion Successive multi-pulsed fractional Er:YAG laser irradiation can result in an increase in collagen fibers and renewal of elastic fibers in superficial dermis of photoaged skin of Guinea pigs.

Objective To explore the relationship of magnetic resonance imaging (MRI) performance in juvenile dermatomyositis (JDM) with clinical characteristics, especially serum muscle enzyme abnormalities. Methods The images of 50 cases of JDM were reviewed, and the affected skin, subcutaneous connective tissue, muscle fascia and muscle were evaluated. The range of muscle edema under MRI images was categorized into 1-3 grades from mild to complete involvement. By comparing the MRI classification with muscle enzyme, we aim to reveal the linkage between the degree of muscle damage and the levels of muscle enzymes. The sequence of MRI examination of the thigh included rapid spin echo sequence FSE T1W, and the fat suppression sequence STIR in both coronary and axial position. Results In the 50 cases of dermatomyositis, there were 49 cases of muscle edema, 28 cases of myofasciitis, 9 cases of subcutaneous connective tissue inflammation, and 4 cases of thickening skin. Of 49 cases of muscle edema, there are 16 cases in grade 1, 24 in grade 2 and 9 in grade 3. The median value of all muscle enzyme in the grade 2 group was higher than that in the other two groups, and the value of AST was statistically significant, P<0.05. Conclusions The detection rate of JDM using MRI is high, which can help judge the severity and range of involvement. The MRI findings of JDM mainly demonstrated muscle edema, mostly moderate degree, followed by muscular fasciitis.