Early and long-standing rheumatoid arthritis: distinct molecular signatures identified by gene-expression profiling in synovia.

INTRODUCTION: Rheumatoid arthritis (RA) is a heterogeneous disease and its underlying molecular mechanisms are still poorly understood. Because previous microarray studies have only focused on long-standing (LS) RA compared to osteoarthritis, we aimed to compare the molecular profiles of early and LS RA versus control synovia. METHODS: Synovial biopsies were obtained by arthroscopy from 15 patients (4 early untreated RA, 4 treated LS RA and 7 controls, who had traumatic or mechanical lesions). Extracted mRNAs were used for large-scale gene-expression profiling. The different gene-expression combinations identified by comparison of profiles of early, LS RA and healthy synovia were linked to the biological processes involved in each situation. RESULTS: Three combinations of 719, 116 and 52 transcripts discriminated, respectively, early from LS RA, and early or LS RA from healthy synovia. We identified several gene clusters and distinct molecular signatures specifically expressed during early or LS RA, thereby suggesting the involvement of different pathophysiological mechanisms during the course of RA. CONCLUSIONS: Early and LS RA have distinct molecular signatures with different biological processes participating at different times during the course of the disease. These results suggest that better knowledge of the main biological processes involved at a given RA stage might help to choose the most appropriate treatment.

PAS inclusions, immunoreactive tenascin and proliferative activity in low-grade chondrosarcomas.

To distinguish between chondrosarcoma (grade 1--borderline histology) and enchondroma, we examined six chondrosarcomas (grade 1--borderline histology) which looked like benign lesions. Their diagnosis, albeit based on clinical, radiologic and pathologic examinations, was not easily reached. Moreover, we examined six enchondromas and 11 chondrosarcomas, the diagnoses of which were straightforward. All cartilaginous tumors were studied, placing emphasis on PAS-positive intracytoplasmic globules. Anti-Ki67 proliferation-associated nuclear antigen antibody and tenascin antibody were applied. The following features were observed in low-grade chondrosarcomas: (1) masses of hyalin and/or myxoid cartilage invading spaces around the tumor, (2) host lamellar bone trabeculae surrounded by cartilage on all sides, (3) tumoral resorption of bone trabeculae. Intracytopasmic hyalin globules (ICG) were more frequently found in malignant than in benign neoplasm (p = 0.042). Moreover, tenascin matrix immunoreactivity was more likely to be observed in benign than in malignant neoplasm (p = 0.029). Ki67 immunoreactivity was more frequent in characterized than in low-grade chondrosarcomas or in enchondromas, where it was null (p = 0.0044).

Septic arthritis of the hip caused by Yersinia enterocolitica: a case report.

We report a case of bacteriologically documented hip infection caused by Yersinia enterocolitica. A 67-year-old male with a history of valvular disease was admitted for pain and motion range limitation in the left hip with a fever. No organisms were recovered by needle aspiration, but Yersinia enterocolitica grew in joint fluid obtained by surgical arthrotomy. Investigations of the gastrointestinal tract were normal, and there was no evidence of endocarditis. After 6 weeks of appropriate antibiotic therapy and immobilization with transtibial traction, the clinical and laboratory test abnormalities improved. However, the patient died from an intercurrent condition. Y. enterocolitica, a well-known cause of reactive arthritis, can cause septic arthritis.