Cell-matrix interactions are thought to influence epithelial structure, growth, and differentiation. Three-dimensional cell cultures were used to study the effects of the composition of the dermal equivalent on the morphology of epithelium grown from HaCaT skin keratinocytes. Three commercial preparations, a basement membrane preparation from a tumor (matrix 1), two preparations consisting of collagen type I and III (matrix 3 and 4) and a noncommercial preparation containing collagen type I (matrix 2) were investigated. The effects of fibroblasts of different origin (vaginal mucosa, oral buccal mucosa, and skin) were investigated in connection with matrix 4. The histomorphology and expression of the proteins PCNA, Ki-67, p53, p21, pankeratin, involucrin, cytokeratin 10 (Ck10), Ck17, Ck19 and collagen type IV were evaluated. Three-dimensional cultures of HaCaT cells gave rise to an epithelium with an immature and hyperproliferative character, showing active proliferation with intense PCNA staining. Both matrix 1 and matrix 2 resulted in an epithelium with budding into the matrix and some degree of layering. These epithelia showed only scattered Ck17 and Ck19 expression but a low terminal differentiation potential as indicated by scattered Ck10 and involucrin staining. The epithelia of cocultures with matrices 3 and 4 were positive for Ck17 and Ck19. However, the epithelium on matrix 3 showed strong expression of the terminal differentiation marker Ck10 and involucrin. This methodological study provides evidence of the importance of standardization of the composition of the matrix to avoid confounding effects on epithelial morphology and protein expression in studies using a three-dimensional epithelial culture model.

No abstract

The findings of this study showing suppressed cellular proliferation and infrequent p53 dysfunction in snuff lesions may partly explain why dysplastic changes are seldom seen in mucosal lesions induced by the Scandinavian type of snuff.

The cause of Sjögren's syndrome remains unclear, but several environmental and genetic factors have been implicated. The Epstein-Barr virus (EBV), among others (e.g., cytomegalovirus, human herpesvirus 6, and retroviruses), has been widely studied in connection with Sjögren's syndrome without conclusive results. To determine the role of EBV infection in patients with Sjögren's syndrome, the presence of EBV deoxyribonucleic acid (DNA) in major and minor salivary gland biopsy specimens was investigated by means of sulfur 35 in situ hybridization and polymerase chain reaction. Additionally, the presence of latent virus proteins EBV latent membrane protein and Epstein-Barr nuclear antigen 2 was analyzed by immunohistochemical methods. Viral DNA, detected by in situ hybridization, was found in 19% of patients with a diagnosis of Sjögren's syndrome and in 3% of controls. All tissues studied were found to be negative for EBV DNA by polymerase chain reaction. EBV latent membrane protein-positive staining was seen in 17% of patients and 22% of control subjects, while Epstein-Barr-positive staining was found in 25% of patients and 39% of controls. The low frequency of EBV DNA detected in the biopsy specimens does not indicate that the virus itself is the cause of Sjögren's syndrome. However, the possibility that the virus acts as a cofactor cannot be ruled out.

The effect of STE varied in the cell lines studied. STE2 increased significantly the proportion of aneuploid cells in HPV-positive oral keratinocytes, but not HPV16 E6/E7 expression. This indicates that tobacco products may enhance the effects of HPV 16 and the risk of DNA aneuploidy increasing risk to malignant transformation.