| 1. |
- Aspenberg, P., et al.
(författare)
-
Drug test chamber : a titanium implant for administration of biochemical agents to a standardized bone callus in situ
- 1988
-
Ingår i: Journal of Biomedical Engineering. - : Elsevier BV. - 0141-5425. ; 10:1, s. 70-73
-
Tidskriftsartikel (refereegranskat)abstract
- A titanium implant in which a conduit is gradually filled with ingrowing bone (the Bone Harvest Chamber) has been modified to allow continuous local treatment of the conduit tissue with biochemical agents. Implants were inserted bilaterally in rabbit tibiae. The tissue content of the bone ingrowth conduits was studied with histology, 99mTc-MDP scintimetry and measurements of total calcium content. Bone was formed in the conduit by endochondral formation starting at both ends and continuing until fusion in the middle. After 2 weeks the bone had not yet met in the middle where fibrous tissue was seen. In eight animals 3H-proline was applied via one of the chambers, with the contralateral chamber as a saline-treated control. The collagen of the harvested tissue from the 3H-proline treated side had a 3H-hydroxyproline content 1000 times greater than had the control side. The 'drug test chamber' makes possible the study of local effects of drugs on healing of mature bone in vivo.
|
|
| 2. |
- Aspenberg, P., et al.
(författare)
-
Failure of bone induction by bone matrix in adult monkeys
- 1988
-
Ingår i: Journal of Bone and Joint Surgery: British Volume. - 0301-620X. ; 70:4, s. 625-627
-
Tidskriftsartikel (refereegranskat)abstract
- Extraskeletal bone formation can be induced in rodents by implantation of demineralised bone matrix and such implantation has been used to treat bone defects in man, but it is uncertain if induction or merely conduction occurs. We studied bone induction in primates by excising segments of the fibulae of adult squirrel monkeys, defatting and demineralising them before reimplanting them into the quadriceps of the same animal. As a control experiment, rat matrix was prepared in exactly the same way and implanted in rats. After six weeks the implants were harvested and either ashed and analysed for calcium content or prepared for histology. In the rats, the calcium content indicated that about 20% of the original matrix had been replaced by new bone. In the monkeys the calcium content was about the same as that in normal body fluid and no bone was seen in histological sections. This result casts doubt on the use of demineralised human bone matrix as a bone inductor, although it may function by other mechanisms.
|
|
| 3. |
- Aspenberg, Per, et al.
(författare)
-
Fibroblast growth factor stimulates bone formation bone induction studied in rats
- 1989
-
Ingår i: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3674 .- 0001-6470. ; 60:4, s. 473-476
-
Tidskriftsartikel (refereegranskat)abstract
- 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 the effect of adding a growth factor to the inductive implant. Pairs of demineralized rat femoral diaphyses were implanted intramuscularly in rats. the marrow canal of one implant in each pair was filled with a carboxymethyl cellulose gel containing 75 ng of recombinant human basic fibroblast growth factor (FGF). the other implant in each pair served as a control. It was either filled with the gel without FGF or left untreated. Bone formation was induced by all the implants after 3 weeks. the amount of mineralized tissue in the FGF-treated implants was 25 percent greater than in untreated controls. the carboxymethyl cellulose gel alone did not affect the bone yield.
|
|
| 4. |
- Aspenberg, Per, et al.
(författare)
-
Rabbit bone matrix induces bone formation in the athymic rat
- 1988
-
Ingår i: Acta Orthopaedica. - : Medical Journals Sweden AB. - 1745-3674 .- 0001-6470. ; 59:3, s. 276-278
-
Tidskriftsartikel (refereegranskat)abstract
- Rabbit and rat bone matrix were implanted in athymic rat muscle, and the bone yield was measured as total calcium content after 4, 6, and 8 weeks. Matrix from both species induced equal amounts of new bone in the athymic rat. In rabbit and normal rat, the xenogenic matrix induced little or no bone formation. Thus, in the case of rabbit and rat, bone induction is species specific due to immunogenic mechanisms. the athymic rat can be used to measure inductive properties of bone matrix from different species.
|
|
| 5. |
- de Luca, S., et al.
(författare)
-
Proteoglycans from chick limb bud chondrocyte cultures. Keratan sulfate and oligosaccharides which contain mannose and sialic acid
- 1980
-
Ingår i: Journal of Biological Chemistry. - 0021-9258. ; 255:13, s. 6077-6083
-
Tidskriftsartikel (refereegranskat)abstract
- The precursors, [ 35S]sulfate and [2- 3H]mannose, were used to study the biosynthesis of keratan sulfate and other oligosaccharides on proteoglycans isolated from Day 8 cultures of chick limb bud chondrocytes. After alkaline borohydride treatment, three fractions with sialic acid were separated by molecular sieve chromatography. The first contained keratan sulfate which was purified by digestion with chondroitinase to remove chondroitin sulfate, followed by molecular sieve and ion exchange chromatography. The purified keratan sulfate contained about 8% of the 35S activity originally in monomer. The chains had an average length of about 40 monosaccharides and contained only trace amounts of mannose (less than 1 residue/three to four chains). The second fraction contained the majority of the [ 3H]mannose originally in monomer, but no 35S activity. This fraction appears to contain oligosaccharide-peptides of the asparagine-N-glycosylamine type because there were no reduced sugars present and the alkaline borohydride treatment extensively degraded the core protein. The composition of the oligosaccharides, with high proportions of mannose, N-acetylglucosamine, galactose, and sialic acid, was consistent with this suggestion. The third fraction consisted of a series of oligosaccharides with sizes between three to six saccharides. They contained N-acetylgalactosaminitol, indicating that they were attached to the core protein by O-glycoside bonds between N-acetylgalactosamine and hydroxyl groups on serine and threonine. Thus, proteoglycans contain two classes of oligosaccharides, a mannose-rich class characteristic of glycoproteins and an O-glycoside class characteristic of mucins, in addition to the chondroitin sulfate and keratan sulfate chains.
|
|
| 6. |
- Lohmander, Stefan, et al.
(författare)
-
Increased levels of proteoglycan fragments in knee joint fluid after injury
- 1989
-
Ingår i: Arthritis and Rheumatism. - : Wiley. - 0004-3591 .- 1529-0131. ; 32:11, s. 1434-1442
-
Tidskriftsartikel (refereegranskat)abstract
- 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 found. At later times after trauma (up to 4 years), many of these patients still had significantly elevated levels of cartilage PG fragments in the joint fluid. In a group of older patients with gonarthrosis, these levels were only moderately elevated, while in patients with acute pseudogout, greatly increased levels were observed. Although longitudinal studies are needed to validate the significance, PG fragments in joint fluid may be a marker for early posttraumatic arthrosis.
|
|
| 7. |
|
|
| 8. |
- Lohmander, Stefan, et al.
(författare)
-
Transient synovitis of the hip in the child : Increased levels of proteoglycan fragments in joint fluid
- 1988
-
Ingår i: Journal of Orthopaedic Research. - 0736-0266. ; 6:3, s. 420-424
-
Tidskriftsartikel (refereegranskat)abstract
- The levels of proteoglycan antigen were measured in joint aspirates from the hip of children with transient synovitis, septic arthritis, Legg-Calve-Perthes' disease and congenital and traumatic dislocation. Significantly increased levels were found in children with transient synovitis and septic arthritis as compared with other conditions. We propose that the proteoglycan antigens in the joint fluid were released form the articular cartilage in a partially degraded from as a result of an increased rate of proteolytic degradation. In transient synovitis, the source of proteolytic activity may be chondrocytes activated by factors released by synovial cells. The release of joint proteoglycan may cause a temporary increase in deformability of the hip cartilage of the child that could be an important pathogenetic mechanism in some of the sequelae of these diseases.
|
|
| 9. |
- Lohmander, Stefan
(författare)
-
Proteoglycans of joint cartilage. Structure, function, turnover and role as markers of joint disease
- 1988
-
Ingår i: Baillière's Clinical Rheumatology. - 0950-3579. ; 2:1, s. 37-62
-
Tidskriftsartikel (refereegranskat)abstract
- Joint cartilage consists of cells embedded in a matrix of fibrous collagen within a concentrated water-proteoglycan gel. The integrity of this matrix is crucial for the biomechanical properties of the joint cartilage. The different components of the matrix are synthesized and degraded by the cartilage cells, a process regulated by the amount of mechanical stress applied to the chondrocytes as well as by peptide factors and hormones present in synovial fluid. The proteoglycans are large macromolecules consisting of a protein core to which are attached multiple chains of glycosaminoglycans and oligosaccharides. During normal and pathological turnover, degradation products are released to the synovial fluid and to the circulation. Newly developed assays allow the sensitive and specific detection of these fragments in joint fluid and serum. Results of experimental and clinical investigations suggest that these assays will be of value in efforts to diagnose, grade and predict the outcome of inflammatory and degenerative joint disease.
|
|
