Within SPIDIA, an EC FP7 project aimed to improve pre analytic procedures, the PAXgene Tissue System (PAXgene), was designed to improve tissue quality for parallel molecular and morphological analysis. Within the SPIDIA project promising results were found in both genomic and proteomic experiments with PAXgene-fixed and paraffin embedded tissue derived biomolecules. But, for this technology to be accepted for use in both clinical and basic research, it is essential that its adequacy for preserving morphology and antigenicity is validated relative to formalin fixation. It is our aim to assess the suitability of PAXgene tissue fixation for (immuno)histological methods. Normal human tissue specimens (n = 70) were collected and divided into equal parts for fixation either with formalin or PAXgene. Sections of the obtained paraffin-embedded tissue were cut and stained. Morphological aspects of PAXgene-fixed tissue were described and also scored relative to formalin-fixed tissue. Performance of PAXgene-fixed tissue in immunohistochemical and in situ hybridization assays was also assessed relative to the corresponding formalin-fixed tissues. Morphology of PAXgene-fixed paraffin embedded tissue was well preserved and deemed adequate for diagnostics in most cases. Some antigens in PAXgene-fixed and paraffin embedded sections were detectable without the need for antigen retrieval, while others were detected using standard, formalin fixation based, immunohistochemistry protocols. Comparable results were obtained with in situ hybridization and histochemical stains. Basically all assessed histological techniques were found to be applicable to PAXgene-fixed and paraffin embedded tissue. In general results obtained with PAXgene-fixed tissue are comparable to those of formalin-fixed tissue. Compromises made in morphology can be called minor compared to the advantages in the molecular pathology possibilities.

We describe the case of an 18-year-old girl with chronic recurrent multifocal osteomyelitis (CRMO) over a period of 10 years. She had suffered predominantly from very painful recurrent swelling of her cheeks. Various therapeutic regimens including nonsteroidal antiinflammatory drugs and steroids had shown only a partial or temporary response. Because tumor necrosis factor-alpha-blocking agents have been successfully applied in Crohn's-associated CRMO and the related SAPHO (synovitis, acne, pustulosis, hyperostosis, and osteitis) syndrome, tumor necrosis factor-alpha-blocking therapy with infliximab was initiated. Thereafter, apart from 1 mild episode, no additional recurrences were observed during 21 months of follow-up. Infliximab was well tolerated, and steroids were tapered off. Our observation indicates that infliximab may be an effective therapeutic option in CRMO.

Fibrous pseudocapsule around hip implants is an invariable finding at revision operations and is believed to release inflammatory mediators that stimulate bone resorption. Reactive oxygen species have been proposed to be causative factors in various disorders with tissue fibrosis. We were interested in investigating whether aseptic loosening is connected with high oxidative stress, and in showing the underlying mechanism of periprosthetic fibrosis and its role in loosening. Levels of oxidative stress markers reduced (GSH) and oxidized (GSSG) gluthatione and malondialdehyde (MDA) were assayed in 28 loose hips and in 12 stable hips revised for high rate of wear and osteolysis. Collagen in the periprosthetic tissues was measured as hydroxyproline content. Osteolysis and polyethylene wear were graded. Increased oxidative stress measured by low GSH/ GSSG ratio as well as by increased MDA level was established in patients compared to controls. Oxidative stress markers intercorrelated significantly. MDA and both GSH and GSSG levels correlated significantly with hydroxyproline level. Levels of GSSG and MDA were higher in hips with greater polyethylene wear. The results suggest that high oxidative stress may play a role in formation of a fibrous membrane observed at revision of loose hips. The fibrous pseudocapsule is probably related to high intraarticular pressure and expansion of the effective joint space. This study may elicit some aspects of the pathogenesis of aseptic hip loosening and aid in future investigations aiming at prevention of this complication. ß

Level IV, therapeutic study. See the Instructions for Authors for a complete description of levels of evidence.

We reviewed 29 patients with intraosseous lipoma treated between 1985 and 2002. Mean patient age was 48 (20-75) years. According to Milgram's classification, ten cases were classified as stage I, 14 as stage II, and three as stage III. All patients were initially treated by curettage. In 11 cases an additional phenolization was performed. The average follow-up was 32 (6-208) months. At the last follow-up, none had any clinical or radiological signs of recurrence. The adequate treatment of a symptomatic intraosseous lipoma is curettage and bone grafting. In the current study, phenolization showed no added benefit. An asymptomatic intraosseous lipoma without impending pathological fracture can be treated conservatively. Résumé