1. Eleven patients with the bone loss of ageing were treated with the vitamin D analogue 1 alpha-hydroxycholecalciferol and calcium for 3--6 months. 2. Muscle biopsies were taken from the vastus lateralis before and after the treatment and the activity of several enzymes was measured. Succinate dehydrogenase and total phosphorylase activities, which are a measure of the oxidative capacity, were low and increased significantly with the treatment. The lactate dehydrogenase activity, which can be taken as a measure of the anaerobic metabolism, was normal and did not change with treatment. The phosphagen stores, ATP and creatine phosphate were low and increased to normal with treatment. 3. Histochemical classification of the fibre composition revealed that the treatment induced an increase in the relative number of fast-twitch a (FTa or type II A) fibres accompanied by a reduction of the fast-twitch b (FTb or type II B) fibres. The cross-sectional area of the FTa fibres also increased with the treatment. 4. The present findings indicate that treatment with the active vitamin D analogue, 1 alpha-hydroxycholecalciferol, and calcium improves the myopathy associated with the bone loss of ageing.

clinicaltrials.gov Identifier: NCT00207064.

Normal synovial membranes and synovial membranes from patients with classic rheumatoid arthritis were investigated for the presence of fibrin and fibronectin by an indirect immunoperoxidase technique. In normal synovial membranes, fibronectin was found around the monolayer of the synovial lining cells. Staining was most intense on the surface and beneath the lining cells, but not detectable in the cytoplasm. Fibronectin was also found in the cytoplasm of the endothelial cells. No staining for fibrin was found in the normal synovial membrane. In synovial membranes from patients with rheumatoid arthritis, large amounts of fibronectin were found around the multilayer of synovial lining cells, in the cytoplasm of the endothelial cells, and in argyrophilic fiber‐rich connective tissue. In superficial areas denuded of synovial lining cells, high amounts of fibronectin were found incorporated in fibrin. In some areas with noninjured synovial lining cells, fibrin was also found, but in this case no fibronectin was incorporated. No fibronectin was found in connective tissue in areas with infiltration of inflammatory cells. After treatment of normal and rheumatoid synovial membranes with hyaluronidase, fibronectin was still present around the lining cells but the staining was found to be more distinct. This study relates the presence of fibrin and fibronectin in the rheumatoid synovial membrane to the high amount of these proteins, recently described, in rheumatoid synovial fluid. It also suggests that fibronectin present in the synovial membrane is produced and secreted by the endothelial cells.