The PCM, a native microenvironment of chondrocytes, protects chondrocytes from apoptosis. Type VI collagen is a functional component of the PCM that contributes to the survival of chondrocytes.

Although the pericellular matrix (PCM) plays a central role in the communication between chondrocytes and extracellular matrix, its composition is largely unknown. In this study, the PCM was investigated with a proteomic approach using chondrons, which are enzymatically isolated constructs including the chondrocyte and its surrounding PCM. Chondrons and chondrocytes alone were isolated from human articular cartilage. Proteins extracted from chondrons and chondrocytes were used for two-dimensional electrophoresis. Protein spots were quantitatively compared between chondron and chondrocyte gels. Cellular proteins, which had similar density between chondron and chondrocyte gels, did not proceed for analysis. Since chondrons only differ from chondrocytes in association of the PCM, protein spots in the chondron gels that had higher quantity than that in the chondrocyte gels were selected as candidates of the PCM components and processed for mass spectrometry. Among 15 identified peptides, several were fragments of the three type VI collagen chains (α-1, α-2, and α-3). Other identified PCM proteins included triosephosphate isomerase, transforming growth factor-β induced protein, peroxiredoxin-4, ADAM (A disintegrin and metalloproteinases) 28, and latent-transforming growth factor beta-binding protein-2. These PCM components were verified with immunohisto(cyto)chemistry for localization in the PCM region of articular cartilage. The abundance of type VI collagen in the PCM emphasizes its importance to the microenvironment of chondrocytes. Several proteins were localized in the PCM of chondrocytes for the first time and that warrants further investigation for their functions in cartilage biology.

One of the major obstacles hindering cartilage repair is the integration of the reparative cartilage with the recipient cartilage. The purpose of this study was to develop an in vitro model that can be conveniently applied to simulate and improve the integration of tissue engineered cartilage with native articular cartilage. This model, a cartilage integration construct, consists of a cartilage explant and isolated chondrocytes. The explant was anchored to agarose gel on a culture plate as agarose gelation at 4 degrees C to seal the gap between the bottom of the explant and culture plate surface. Isolated chondrocytes were added and confined in the defect created in the center of the explant. After 4 weeks of culture, neocartilage containing proteoglycans and type II collagen was formed. Minimal integration occurred between the neocartilage and the cartilage explant, resembling the failure of cartilage integration manifested in experimental and clinical cartilage repair. In this model, agarose gel anchors the explant onto culture plate by altering temperatures and effectively prevents "leakage" of the isolated chondrocytes from the defect of the explant. This model provides a convenient simulation of the cartilage integration process in vitro and has applications in studies of cartilage integration and cartilage tissue engineering.

A new surgical technique for thymectomy is presented. Three hundred and seventeen patients with myasthenia gravis and 20 with thymomas who had myasthenic symptoms were operated on. The new surgical approach-a small transverse sternotomy-was used in 257 cases (in 240 patients with myasthenia gravis and 17 with thymomas) and conventional median sternotomy in 80. In myasthenic patients small transverse sternotomy enabled radical thymectomy to be performed with an uneventful postoperative course and very good cosmetic results. There were no hospital deaths among patients with myasthenia gravis after thymectomy. The long term results, assessed after 18-24 months, were good: the total remission rate was 39-5%, and there was a great improvement in 48-5% and an improvement in 9%. After thymectomy about 30% of patients received supplementary treatment with prednisone. A correlation between the duration of symptoms and the result of thymectomy was established: the shorter the duration of myasthenia gravis the better the results. In the small group of 20 patients with thymomas two died in hospital. In 12 patients with encapsulated thymic tumours the long term results were similar to those in patients with myasthenia gravis, whereas in patients with infiltrating thymic tumours the results were unsatisfactory.

The aim of this study was to determine the motivation of patients (n = 73) who had undergone microsurgical refertilization for further treatment (assisted reproduction) and the demand for medical counseling. By an interview, 57/73 patients could be evaluated for motivation, further demand for medical counseling, and the postoperative outcome (patency rate). In all, 60% of the patients who failed the treatment and 33% with a patent anastomosis mentioned interest for further counseling, especially for assisted reproduction. The satisfaction rate after the refertilization was nearly identical in the two groups (67%/64%). Following microscopical vasovasostomies the patency was 92%, which was significantly different from that observed after macroscopical refertilization (55%). In conclusion, the standard for refertilization is the microsurgical technique. Furthermore, there is a strong need for counseling that involves urological-andrological advice given by the same work group, including advisement on the techniques of assisted reproduction that might be necessary following the operative treatment.