Implantation of demineralized bone matrix in rodents elicits a series of cellular events leading to the formation of new bone inside and adjacent to the implant. This process is believed to be initiated by an inductive protein present in bone matrix. It has been suggested that local growth factors may further regulate the process once it has been initiated. This investigation was designed to study

Flexor tendon segments were incubated in a diffusion chamber in the subcutis of rabbits. Tendons incubated up to 6 weeks in the diffusion chamber showed proliferating and migrating cells from the epitenon cell layer as well as viable endotenon cells. Explants frozen in liquid nitrogen prior to incubation showed no signs of extrinsic cell contamination and remained non-viable indicating that no cel

We measured the levels of cartilage proteoglycan (PG) fragments in knee joint synovial fluid obtained from patients with previous trauma of the knee, early gonarthrosis, or pyrophosphate synovitis, and in age-matched control subjects. During the initial 3-4 weeks after rupture of the anterior cruciate ligament or the meniscus (confirmed by arthroscopy), markedly increased PG fragment levels were f

Rat chondrosarcoma chondrocytes were labeled with [3H]serine or [3H]mannose as a precursor. Intracellular proteoglycan core protein precursor was purified from cell lysates by immunoprecipitation with polyclonal antibodies against the hyaluronic acid-binding region, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The core precursor was eluted from the gels and treated with a

The structure, biosynthesis, and metabolism of proteoglycans in the HL-60 human promyelocytes were studied by metabolic labeling in culture with [35S]sulfate, [3H]glucosamine, [3H]serine, and [3H]leucine. These cells synthesize a single predominant species of intracellular proteoglycan with an approximate molecular weight of 100,000. The cells contain about 1 μg of proteoglycan/million cells. The

Flexor tendons have an intrinsic ability for repair, with a capacity to metabolize matrix components and to proliferate. To identify factors with the potential of affecting those abilities, the effects of recombinant human insulin-like growth factor (rhIGF-I), insulin and fetal calf serum (FCS) on the synthesis of proteoglycan, collagen, and non-collagen protein and cell proliferation were investi

The effects of human recombinant insulin-like growth factor-I (rhIGF-I, 50 ng/ml) on matrix metabolism in the deep flexor tendon from the tendon sheath region of the rabbit were studied in explants cultured for 3 weeks. Tendon segments cultured in medium supplemented with fetal calf serum (FCS) exhibited proliferation of the superficial cell layers. Synthesis of proteoglycan and non-collagen prote

High tibial osteotomy was performed for medial gonarthrosis in 28 patients. Preoperatively, and at 3, 12, and 24 months after surgery, clinical and radiographic examinations were made, and joint-fluid samples were aspirated. Arthroscopy was performed preoperatively and at 24 months. Immunoassay of proteoglycan epitope in joint fluid showed an increase in concentration at all times as compared with

Demineralized bone matrix from young and adult monkeys was implanted intramuscularly for 6 weeks in athymic rats and adult monkeys. Cartilage and bone induction was evaluated by histology and calcium content. In the athymic rat, most implants induced cartilage or bone. In the monkeys, cartilage was formed only on rare occasions and there was no sign of bone formation. We conclude that (a) adult mo

Implantation of demineralized bone matrix in rodents elicits a series of cellular events leading to the formation of new bone inside and adjacent to the implant. This process is believed to be initiated by an inductive protein present in bone matrix, and local growth factors may further regulate the process. We have previously shown that local application of recombinant human basic fibroblast grow

Segments of the deep flexor tendon of the rabbit were exposed to air; the effects of dehydration on in vitro synthesis of proteoglycan, collagen, non-collagenous protein, and cell proliferation were compared with tendon segments that were kept moist with physiologic saline. After 20 min of expo-sure to air, the tendons lost half and after 40 min all of their ability to synthesize matrix components

The mechanisms involved in the disease process in arthrosis are largely unknown, with genetics, joint malalignment, overload or trauma, obesity, and aging as some of the known or suspected contributing factors. Even less well known is how these general factors are translated into disease mechanisms at the cell and tissue levels. However, it may be argued that degradation of cartilage matrix is a k

Osteoarthritis is a major cause of disability and early retirement. Yet we lack the means to diagnose the disease in its early stages or to monitor the effects of treatment on the target tissue, the joint cartilage. Neither can we identify the disease mechanisms at the tissue or cell level. Current research focuses on the use of markers of cartilage matrix metabolism in body fluids as a means to d

The ability of rabbit deep flexor tendons to restore the gliding surface and to heal, without the normal contribution of the superficial epitenon layer of the tendons, was studied by light and scanning electron microscopy. The epitenon layer was carefully removed, from defined segments of the tendons. The remaining central tendon tissue was divided, sutured and placed in diffusion chambers subcuta

Synovial fluid was collected from patients with recent knee injury and from patients with early or late stage osteoarthritis. Chondroitin sulfate-substituted aggrecan fragments present in these fluids, and in normal bovine synovial fluid, were purified by cesium chloride gradient centrifugation, enzymically deglycosylated and fractionated by gel filtration on Superose-12. Each sample contained two

High tibial osteotomy for medial gonarthrosis was performed in 28 patients (28 knees). At the time of surgery, arthroscopy was also performed and a cartilage-bone biopsy was obtained. Postoperatively, 15 patients were randomized to a cylinder plaster cast, whereas 13 patients had a hinged cast brace for early knee mobilization. At follow-up examination, two years after surgery, 16 patients accepte

We determined the concentration of proteoglycan fragments in knee joint fluid collected from knee-ligament injured patients more than 6 months after the trauma and from patients with acute pyrophosphate arthritis and arthrosis or with arthrosis only. Injured patients with normal or only mildly altered cartilage at arthroscopy and with normal radiographs, had twice the average concentration of heal

A nonimmunocompromised 32-year-old man with arthrosis of the knee participated as a placebo control in a clinical trial of intraarticular injections of hya-luronan. After the fourth weekly injection of saline, he developed a warm and swollen knee, and synovia! fluid cultures revealed growth of Candida albicans. Oral fluconazole treatment was instituted 2 weeks after onset of symptoms, but failed t

The concentration of cartilage proteoglycan fragments in knee joint fluid was measured before and after one event of physical exercise in 33 healthy athletes. Nine athletes ran on a treadmill for 60 min, 16 ran on road for 80 min and 8 played one soccer game (90 min). Before exercise, the levels of proteoglycan fragments in the athlete joint fluid were lower than in a previously analyzed reference