Facial dermatosis associated with Demodex: a case-control study.

Demodex has been considered to be related with multiple skin disorders, but controversy persists. In this case-control study, a survey was conducted with 860 dermatosis patients aged 12 to 84 years in Xi'an, China to identify the association between facial dermatosis and Demodex. Amongst the patients, 539 suffered from facial dermatosis and 321 suffered from non-facial dermatosis. Demodex mites were sampled and examined using the skin pressurization method. Multivariate regression analysis was applied to analyze the association between facial dermatosis and Demodex infestation, and to identify the risk factors of Demodex infestation. The results showed that total detection rate of Demodex was 43.0%. Patients aged above 30 years had higher odds of Demodex infestation than those under 30 years. Compared to patients with neutral skin, patients with mixed, oily, or dry skin were more likely to be infested with Demodex (odds ratios (ORs) were 2.5, 2.4, and 1.6, respectively). Moreover, Demodex infestation was found to be statistically associated with rosacea (OR=8.1), steroid-induced dermatitis (OR=2.7), seborrheic dermatitis (OR=2.2), and primary irritation dermatitis (OR=2.1). In particular, ORs calculated from the severe infestation (≥5 mites/cm(2)) rate were significantly higher than those of the total rate. Therefore, we concluded that Demodex is associated with rosacea, steroid-induced dermatitis, seborrheic dermatitis, and primary irritation dermatitis. The rate of severe infestation is found to be more correlated with various dermatosis than the total infestation rate. The risk factors of Demodex infestation, age, and skin types were identified. Our study also suggested that good hygiene practice might reduce the chances of demodicosis and Demodex infestation.

[Expression of integrin beta1 in squamous cell carcinoma].

OBJECTIVE: To study the expression of integrin beta1 in squamous cell carcinoma (SCC) and explore the relationship between stem cell marker and SCC. METHODS: The expressions of integrin beta1 in SCC tissues and SCC cell strain A431 were detected with immunohistochemical methods and cell staining method. The differentiation of SCC cells were induced with all-trans-retinoic acid (ATRA). The changes of integrin beta1 levels before and after induction were detected with RT-PCR. RESULTS: In highly differentiated SCC tissues, integrin beta1 was constantly expressed in the basal-like cells in the edge of tumor; some cells inside arranged as island also showed positive integrin beta1 expression. In poorly differentiated SCC tissues, island-like integrin beta1-positive cells remarkably increased and distributed in a diffuse way. In SCC A431 cells, integrin beta1 was expressed unevenly in tumor cells. After treatment by ATRA, level of integrin beta1 mRNA in A431 cells significantly decreased compared with untreated control (P < 0.05), and the ratios between the intensity values of integrin beta1 to beta-actin were 0.071 +/- 0.025 and 0.029 +/- 0.018 at 24 h and 48 h, respectively, whereas in controls were 0.148 +/- 0.027 and 0.136 +/- 0.011 (P < 0.05). CONCLUSIONS: Integrin beta1 is heterogeneously expressed in both SCC tissues and SCC A431 cells. The expression of Integrin beta1 decreases when the differentiation level of tumor cells increase, indicating that integrin beta1 is closely related with the initiation of SCC and potential cancer stem cells in SCC.

[Inhibition of promyelocytic leukemia gene by tazarotene in hyperproliferative epidermis of psoriasis].

OBJECTIVE: To investigate the mechanism of tazarotene against active psoriasis vulgaris. METHODS: A randomized, controlled trial was conducted in 43 patients with active psoriasis vulgaris, who were divided into tazarotene and control groups. Promyelocytic leukemia (PML) mRNA in active psoriatic lesions before and 14 days after tazarotene treatment was detected by in situ hybridization. RESULTS: PML mRNA expression was detected not only in the basal layer (86.96%), but also in the suprabasal layers of the epidermis in the manner of focal expression (78.26%). After tazarotene treatment, virtually no PML mRNA expression could be detected in the psoriatic lesions (8.69% in the basal layer and 4.35% in the suprabasal layers). PML mRNA expression in the control group underwent no obvious changes during the observation. CONCLUSIONS: Tazarotene may inhibit abnormal proliferation of keratinocytes through down-regulating PML gene expression in active psoriatic epidermis.