The aim of the study was to investigate the relationship between invasion and proliferation in rheumatoid arthritis synovial fibroblasts (RASFs). In vitro, RASFs, normal synovial fibroblasts (NSFs), and RASFs transformed with SV40 T-antigen (RASF(SV40)) were analyzed for the expression of cell surface markers (Thy1, VCAM-1, ICAM-1, CD40, CD44) and their proliferation by flow cytometry. Furthermore, colony-forming unit assays were performed and the expression of matrix metalloproteinases (MMP)-14 and cathepsin K mRNA were determined by real-time polymerase chain reaction. In vivo, in the severe combined immunodeficiency (SCID) mouse co-implantation model, RASFs, NSFs, and RASF(SV40) were tested for cartilage invasion, cellular density, and for their expression of the cell cycle-associated protein Ki67. In the SCID mouse co-implantation model, RASFs invaded significantly stronger into the cartilage than NSFs and RASF(SV40). Of note, RASF(SV40) cells formed tumor-like tissues, and the cellular density adjacent to the cartilage was significantly higher than in RASFs or NSFs. In turn, the proliferation marker Ki67 was strongly expressed in the SV40-transformed synoviocytes in SCID mice, but not in RASFs, and specifically not at sites of cartilage invasion. Using the colony-forming unit assay, RASFs and NSFs did not form colonies, whereas RASF(SV40) lost contact inhibition. In vitro, the proliferative rate of RASFs was low (4.3% S phase) in contrast to RASF(SV40) (24.4%). Expression of VCAM-1 was significantly higher, whereas of ICAM-1 was significantly lower, in RASFs than in RASF(SV40). CD40 was significantly stronger expressed in RASF(SV40), whereas CD44 and AS02 were present at the same degree in almost all synoviocytes. Expression of cathepsin K and matrix metalloproteinase-14 mRNA was significantly higher in RASFs than in the RASF(SV40). Our data demonstrate clearly that invasion of cartilage is mediated by activated RASFs characterized by increased expression of adhesion molecules, matrix-degrading enzymes, but does not depend on cellular proliferation, suggesting the dissociation of invasion and proliferation in RASFs.

Objective. Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by a hyperplastic synovial tissue, inflammatory infiltrates, and a progressive destruction of cartilage and bone. FLICE-inhibitory protein (FLIP) prevents the association of caspase 8 with FADD and thus exerts an antiapoptotic effect through inhibition of Fas-mediated apoptosis. We undertook this study to examine the expression of FLIP in RA, osteoarthritic (OA), and normal synovial tissues.

We characterized a full length L1 mRNA in a rheumatoid arthritis (RA) synovial tissue and determined the degree of methylation of its 5'-UTR. We asked whether not only intact but also altered L1s can exert biological activities by transfecting RA synovial fibroblasts (SF) with either retrotransposition-competent or incompetent L1s and examined their capacity to induce p38delta. Total RNA was isolated from the synovial tissue of a 35-year-old woman with highly destructive RA. A complete L1 sequence was obtained by 3'/5'-RACE. Methylation of the genomic 5'-UTR was determined by the sodium-disulfide/PCR method. RA-SF were transfected by lipofection with either a functional L1 or an ORF2-mutated L1 element. The expression of p38delta was measured by RT-PCR and Western blot. The full length L1 mRNA included a 5'-UTR, an ORF1 and an ORF2. Three of five CpG islands (60%) of the genomic L1 5'-UTR were hypomethylated and the ORF2 was deactivated by the insertion of stop codons. Both, intact and ORF2-mutated L1 vectors, induced the expression of p38delta. Thus, even an ORF2-mutated L1 element, as expressed in RA, is biologically active and both L1 ORF1 and p38delta transcripts may appear as a consequence of genomic hypomethylation. The induction of p38delta appears to be mediated by an ORF1/p40-dependent process. This is the first indication of a p40 mediated transactivation.

Both consolidation and expansion properties of a packed bed of superabsorbent hydrogel particles under the action of the mechanical loads were investigated in various ionic environments using a KCl solution to clarify the role of the osmotic pressure of the solution on the deformation behaviors of hydrogel particles. A description of the consolidation process was accomplished through the use of either the modified Terzaghi model or a simplified computation method. As the concentration of KCl solution increased, the consolidation rate increased and the packed hydrogels became denser. The data were well analyzed based on the idea of the effective osmotic pressure of the solution. Moreover, in the expansion process of the compressed bed of hydrogel particles, it was determined that the secondary expansion effect known as the creep effect plays an important role on the expansion behavior. It was found that expansion proceeds more slowly than consolidation. © 2006 American Institute of Chemical Engineers AIChE J, 2007

The nucleoprotein structure in the vicinity of the four replication origins of the extrachromosomal rDNA of the slime mould Physarum polycephalum was examined. At limited extents of digestion with micrococcal nuclease, a series of cleavage sites were found in the proximity of the orgins of replication. The distance between the sites reflected an altered nucleosomal organization of rDNA chromatin. It could be demonstrated that the cleavage sites were not the result of sequence-specific cutting of micrococcal nuclease. Such a different organization of rDNA chromatin was supported by recent findings that regions close to the origins of replication were inaccessible to cross-linking with psoralen. In addition, the same area contained sites that were protected from restriction endonuclease digestion (i.e., possible anchoring sites for the rDNA to the nucleolar matrix). Therefore, our results suggest that the nucleoprotein complexes presented in this paper are involved in anchoring and (or) in the replication of the rDNA.