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Biomedical subjects

I Clemmensen

Publications and source records attributed to I Clemmensen.

At least 73 records · Page 4Linked to original sources
PubMed1984

Plasma fibronectin concentration in patients admitted to intensive care unit.

The plasma fibronectin level was determined by immunoelectrophoresis in patients under intensive care. The decrease in plasma fibronectin concentration was most pronounced in patients with sepsis and DIC. Survival of these patients was related to the extent of decrease of the plasma fibronectin concentration. Burn injury and the associated surgical treatment were followed by a decrease in fibronectin concentration which then normalized in 24-48 h after the burn injury. It is concluded that serial determinations of plasma fibronectin are essential for studying the relation of a low plasma fibronectin with the clinical condition.

Adolescent↗
PubMed1983

Fibrin and fibronectin in rheumatoid synovial membrane and rheumatoid synovial fluid.

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.

Arthritis, Rheumatoid↗
PubMed1983

Demonstration of fibronectin in normal and injured aorta by an indirect immunoperoxidase technique.

The presence and localization of fibronectin in normal and mechanically injured aorta in rabbits was studied using an indirect immunoperoxidase technique on tissue specimens fixed in formaldehyde, embedded in paraffin and pretreated with pepsin. The effect on staining quality of treatment with testicular hyaluronidase prior to immunoperoxidase staining was also examined. In the intima from normal aorta fibronectin was present in the subendothelial basal layer, along the internal and external elastic laminae, around and between the smooth muscle cells of the media and along the collagen and elastic fibres in the adventitia. Sixteen days after a single mechanical dilatation of the descending thoracic aorta all animals developed gross atherosclerotic-like changes. Microscopic examination revealed prominent neo-intimal hyperplasia with subendothelial, cushion-like thickenings but no medial or adventitial alterations. Fibronectin, in increased amounts, was found between and around the endothelial cells and in the subendothelial thickenings between the proliferating smooth muscle cells in relation to the fine, thin elastic and argyrophilic fibres. In the media and adventitia the amount and distribution of fibronectin was indistinguishable from uninjured control aortas. Treatment with testicular hyaluronidase before immunoperoxidase staining resulted in a higher staining resolution in normal and injured aorta. The conspicuous observation in the present study is that fibronectin exclusively accumulates in areas of tissue repair. The origins and functions of fibronectin during tissue injury and repair are discussed.

Animals↗
PubMed1983

Plasma fibronectin concentrations in patients with liver diseases.

Plasma, obtained just prior to diagnostic liver biopsy in 71 patients with various liver diseases, was examined by electroimmunoassay using immunoglobulin against human fibronectin and purified plasma fibronectin as standard. The plasma fibronectin concentration was not significantly different from age- and sex-matched healthy controls in patients with chronic persistent or chronic active hepatitis (n = 7), primary biliary cirrhosis (n = 8), alcoholic fatty liver (n = 9), alcoholic hepatitis (n = 10), and alcoholic cirrhosis (n = 16). Patients with acute viral hepatitis (type A (n = 2); type B (n = 7); type non A, non B (n = 1] had significantly (P less than 0.01) raised plasma fibronectin concentrations (median 506 mg/l (range 339-804] compared to controls (median 399 mg/l (range 304-462]. Morbidly obese patients with fatty liver (n = 11) had significantly (P less than 0.001) raised plasma fibronectin concentrations (median 610 mg/l (range 429-862] compared to controls (median 361 mg/l (range 303-419].

Chromatography, Affinity↗
PubMed1983

Plasma fibronectin concentration in patients with chronic renal failure and treated with haemodialysis.

By quantitative electroimmunoassay the plasma fibronectin concentration was determined in 42 patients with chronic renal failure and treated with haemodialysis. The plasma fibronectin concentration was significantly reduced, independent of the haemodialysis, compared to a control group. Delayed wound healing seen in patients with chronic renal failure might be a result of the reduced plasma fibronectin.

Adolescent↗
PubMed1982

A fibronectin-binding glycoprotein from human platelet membranes.

Fibronectin ('cold-insoluble globulin') has been suggested as a possible mediator of platelet adhesion. A fibronectin-binding protein as partially purified from washed solubilized human platelet membranes by affinity chromatography on fibronectin-Sepharose. The isolated protein migrated as a single band on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis with an Mr (relative molecular mass) of approx. 125 000 under reducing conditions. The protein migrated as a dimer in non-reduced gels. The purified protein did not react with immunoglobulins against fibrinogen or fibronectin when tested in crossed immunoelectrophoresis or electroimmunoassay. The protein and purified fibronectin formed a complex that had a significantly faster mobility in crossed immunoelectrophoresis than did native fibronectin. The presence of heparin in the binding-protein-fibronectin mixture resulted in an even faster mobility of the complex, whereas the mobility of native fibronectin was unaffected. Crossed affinoimmunoelectrophoresis of the complex using different lectins suggested that the binding protein is a glycoprotein containing N-acetylglucosamine residues. The complex, but not purified fibronectin, bound to phenyl-Sepharose on crossed hydrophobic-interaction immunoelectrophoresis. The results strongly suggest the presence of a fibronectin-binding glycoprotein in the platelet membrane.

Blood Platelets↗
PubMed1982

Different molecular forms of fibronectin in rheumatoid synovial fluid.

The concentration of fibronectin in rheumatoid synovial fluid was found to be 2-3 times higher than in the corresponding plasma. Normal plasma revealed a homogeneous precipitate by cross- immunoelectrophoresis using antifibronectin, while rheumatoid plasma and rheumatoid synovial fluid exhibited a heterogeneous precipitate. The heterogeneous precipitate in rheumatoid plasma was found to be a complex between fibronectin and fibrinogen as evidenced by cross-immunoelectrophoresis. Synovial fluid fibronectin demonstrated a lower molecular weight by gelfiltration on Sepharose CL6B than did normal plasma fibronectin. We suggest that the presence of degraded fibronectin in rheumatoid synovial fluid may be the result of either the degradation of fibrin-fibronectin complexes or the destruction of matrix fibronectin from the synovial tissue.

Adult↗
PubMed1982

The value of hyaluronidase treatment of different tissues before demonstration of fibronectin by the indirect immunoperoxidase technique.

The influence of testicular hyaluronidase treatment on the immunohistochemical localization of fibronectin in different tissues (human articular cartilage, large intestine, synovial membrane and experimental granulation tissue) as well on frozen as on formaldehyde fixed, paraffin embedded tissue, has been studied using the indirect immunoperoxidase technique. Pretreatment with hyaluronidase is essential in demonstrating fibronectin in frozen sections of human articular cartilage. In the other tissues examined treatment with hyaluronidase was not essential, but gave a more optimal staining quality. The effect of hyaluronidase treatment was to some extent dependent on the duration of treatment. In formaldehyde fixed, paraffin processed tissue the improvement with hyaluronidase treatment was only seen when the hyaluronidase followed pepsin digestion of the deparaffinized tissue sections.

Cartilage↗
PubMed1982

Demonstration of fibronectin in human articular cartilage by an indirect immunoperoxidase technique.

Fresh frozen tissue sections of human articular cartilage was treated without and with human testicular hyaluronidase (2 x 10(6) units/l) for 60 min at 37 degrees C and stained by the indirect immunoperoxidase technique with rabbit antihuman fibronectin. The rabbit antihuman fibronectin was purified by affinity chromatography on human fibronectin-Sepharose. Fibronectin was only found on the acellular surface of the articular cartilage in tissue sections not treated with hyaluronidase. In this surface layer, probably identical to "lamina splendens", the arrangement of fibronectin was as a membrane. No collagen was seen in this area by van Gieson staining. No staining for fibronectin was found in the cartilage matrix or in the chondrocytes. Treatment of the cartilage tissue with hyaluronidase resulted in visualization of high amount of fibronectin in the cartilage matrix, with the highest intensity around the chondrocytes. The staining of the acellular surface layer of the articular cartilage was identical with the results obtained without hyaluronidase treatment. These results indicate that articular cartilage is rich in fibronectin probably in complex with hyaluronic acid, and that the chondrocytes produce fibronectin in situ. It also demonstrates the steric hindrance of hyaluronic acid aggregates in diffusion of the antibody and the value of hyaluronidase treatment of tissue before demonstration of fibronectin.

Cartilage, Articular↗
PubMed1982

Plasma fibronectin concentration in normal subjects.

The plasma concentration of fibronectin was determined in 374 normal subjects, newborn to 85 years of age, by quantitative electroimmunoassay. The plasma fibronectin concentration was higher in males than in females and the concentration increased with age. No day to day or diurnal variation was found. Different stabilizers of blood did not influence the results.

Adolescent↗
PubMed1982

Fibronectin in experimental granulation tissue.

The temporal appearance of fibronectin in experimental granulation tissue has been studied using the immunoperoxidase technique on material fixed in formaldehyde, embedded in paraffin and pretreated with pepsin. Furthermore, the relationship between the distribution of fibronectin and connective tissue fibres, demonstrated as either argyrophilic or red by the van Gieson method, has been investigated. Fibronectin was demonstrated as part of the fibrinous network in the sponge before the formation of granulation tissue. In the development of granulation tissue fibronectin was seen in the initial cellular stage codistributed with the newly formed fibres, first the argyrophilic fibres and later with those stained red by the van Gieson method, too. With maturation of the granulation tissue, predominated by these fibres, the amount of fibronectin was gradually reduced. The presence of fibronectin in the sponge already before the formation of granulation tissue suggests that fibronectin in the initial stage of inflammation derives from plasma. The increase in amount of fibronectin corresponding to the cellular (fibroblastic) proliferation and the formation of fibres, both argyrophilic and van Gieson positive, indicates that fibronectin in young granulation tissue is synthesized by fibroblastic cells. The relationship between the morphologically demonstrated argyrophilic fibres and van Gieson positive fibres and the biochemical type III and type I collagens is discussed.

Animals↗
PubMed1982

Isolation of a fibronectin-binding protein from Staphylococcus aureus.

Fibronectin ("cold-insoluble globulin") has been suggested to play a role in cell-to-cell and cell-to-substratum adhesions. The 70-kilodalton terminal part of human fibronectin has recently been shown to bind to Staphylococcus aureus. In the present study, a fibronectin-binding protein was purified from sonicated S. aureus strain E2371 by affinity chromatography on fibronectin-Sepharose. The fibronectin-binding protein was isolated from an extract of sonicated S. aureus containing at least 57 different proteins as determined by crossed immunoelectrophoresis in antibodies to sonicated S. aureus. The fibronectin-binding protein was released from fibronectin-Sepharose by carbamide (8 M). No impurities in the final preparation could be detected when tested in crossed immunoelectrophoresis. By polyacrylamide gel electrophoresis in both reduced and unreduced gels, the protein showed two bands with relative molecular masses of 197,000 and 60,000, respectively. A complex between the purified S. aureus protein and fibronectin could be demonstrated by crossed immunoelectrophoresis both in monospecific antibodies against fibronectin and in S. aureus polyspecific antibody.

Animals↗
PubMed1981

Kinetics of plasmin inhibition in the presence of a synthetic tripeptide substrate. The reaction with pancreatic trypsin inhibitor and two forms of alpha 2-plasmin inhibitor.

The progressive inhibition of plasmin by pancreatic trypsin inhibitor and by alpha 2-plasmin inhibitor in the presence of D-valyl-L-leucyl-L-lysine 4-nitroanilide was investigated. The kinetics with plasmin were compared with those with miniplasmin. The kinetic properties of two functionally different forms of alpha 2-plasmin inhibitor described by Clemmensen [(1979) in The Physiological Inhibitors of Coagulation and Fibrinolysis (Collen. D., Wiman, B & Verstraete, M., eds.), pp 131-136, Elsevier, Amsterdam] were characterized. The two forms differ in their plasminogen-binding capability, and this difference can account for a difference in secondary site interaction suggested from the kinetics. The binding of inhibitor to miniplasmin is a simple pseudo-first-order reaction with both pancreatic trypsin inhibitor and the two alpha 2-plasmin inhibitor forms. Such simple kinetics are also observed for the reaction between plasmin and the non-plasminogen-binding form of alpha 2-plasmin inhibitor. More complicated kinetics are obtained for the reaction between plasmin and the alpha 2-plasmin inhibitor form that binds to plasminogen. With both forms of the alpha 2-plasmin inhibitor, a complex stable to acetic acid/urea and gel electrophoresis is present and fully developed 15 s after initiation of the reaction with plasmin.

Aprotinin↗
PubMed1981

Adsorption to fibrin of native fragments of known primary structure from human plasminogen.

Limited proteolysis of native Glu-plasminogen with pancreatic elastase produced three major fragments, K1+2#3, K4, K5-light chain (miniplasminogen). Fibrin-binding was determined by clotting fibrinogen in the presence of 125I-labelled fragments and measuring 125I in the washed fibrin and in the supernatant. Of the fragments miniplasminogen showed the highest fibrin-binding, the strength of which was intermediate between those of Glu-plasminogen and Lys-plasminogen. The fibrin-binding of all three fragments was decreased by 6-aminohexanoic acid or tranexamic acid. This decrease was most pronounced with K1+2+3. The fibrin-binding of K1+2+3, but not that of K4 and miniplasminogen was decreased by alpha 2-antiplasmin. The fibrin-binding of K1+2+3 and mini-plasminogen was lower in a plasma clot than in a purified fibrin clot. Our results indicate that each of the three fragments can bind to fibrin. They confirm that an alpha 2-antiplasmin-binding site is located on K1+2+3. Furthermore two of the fragments, namely K4 and K1+2+3 contain lysine-binding site(s).

Binding Sites↗
PubMed1981

The influence of fixation and tissue preparation on the immunohistochemical demonstration of fibronectin in human tissue.

The influence of fixation and tissue preparation on the immunohistochemical localization of human fibronectin in gastrointestinal tract tissue has been examined using indirect immunoperoxidase technique. The most optimal staining result with strong intensity and well defined localization was obtained on frozen sections of unfixed material. Nearly identical results with improved morphology were obtained when staining paraffin sections of tissue fixed in 96% ethanol, 96% + 1% acetic acid and absolute acetone. All other fixatives tested, 10% neutral buffered formalin. Lillie's AAF, Bouin's fixative, Clarke's fixative, 4% formaldehyde, 4% formaldehyde + 0.5% cetylpyridiniumchloride (F-CPC), 4% formaldehyde +0.1% glutaraldehyde gave unsatisfactory results. However, proteolytic digestion with pepsin of paraffin sections prior to staining of buffered formalin and F-CPCfixed material gave results comparable with those obtained on unfixed frozen sections are regards definition of the staining whereas staining intensity was decreased in some degree. No improvement was observed when using proteolytic digestion of tissue fixed in other fixatives.

Colon↗