Biomedical subjects

I Clemmensen

Publications and source records attributed to I Clemmensen.

At least 55 records · Page 3Linked to original sources

PubMed1986

Purification and characterization of a novel, oligomeric, plasminogen kringle 4 binding protein from human plasma: tetranectin.

Purification of alpha 2-plasmin inhibitor (alpha 2PI) from human plasma by affinity chromatography on plasminogen-Sepharose resulted in copurification of a contaminating protein with Mr 17,000 as judged by sodium dodecyl sulphate/polyacrylamide gel electrophoresis. This contaminating protein could not be removed from the purified alpha 2-PI preparation by several types of gel chromatography applied. The use of the kringle 1-3 part of plasminogen, K(1 + 2 + 3), bound to Sepharose for affinity chromatography, instead of plasminogen-Sepharose, resulted in an alpha 2PI preparation without this contaminant. The contaminating protein was found to interact specifically with the kringle 4 part of plasminogen (K4) and not with K(1 + 2 + 3) or miniplasminogen. The K4-binding protein was purified by ammonium sulphate precipitation, affinity chromatography on K4-Sepharose, ion-exchange chromatography and gel filtration on AcA 34. The relative molecular mass of the protein (Mr 68 000) was estimated by gel filtration. This suggests a tetrameric protein composed of four subunits (Mr 17,000), that are dissociated by 1% sodium dodecyl sulphate. Dissociation into subunits was also demonstrated by gel filtration in the presence of 6 M guanidine hydrochloride. A specific antibody was raised in rabbits against the purified protein and this antibody was shown not to react with any known fibrinolytic components. The pI of the K4-binding protein was found to be 5.8. The first three N-terminal amino acids were determined to be Glu-Pro-Pro. The concentration of the protein in plasma was estimated to be 0.20 +/- 0.03 microM (15 +/- 2 mg/l). The electrophoretic mobility of the K4-binding protein was shown by crossed immunoelectrophoresis to be influenced by the presence of Ca2+, EDTA and heparin. The protein was found to enhance plasminogen activation catalyzed by tissue-type plasminogen activator (t-PA) in the presence of poly(D-lysine). The protein appeared to be a novel plasma protein tentatively called 'tetranectin'.

Blood Proteins↗

PubMed1986

Circulating monoclonal IgM lambda cryoglobulin with collagen type I affinity in vasculitis.

A previously fit 66-years-old male primarily presented symptoms compatible with Henock-Schönlein's purpura, from which he seemingly recovered. Shortly hereafter he relapsed with an IgM lambda essential monoclonal cryoglobulinemia type I, presenting a systemic, necrotizing vasculitis, with low titer of circulating immune complexes and complement consumption. Glucocorticoid treatment and plasmapheresis did not prevent an ultimately lethal course. An indirect immunoperoxidase technique showed that the cryo-IgM bound to the interstitial connective tissue corresponding to the localization of collagen type I. In addition it bound to affinity purified human procollagen type I. These results indicate, that the IgM lambda of the proband was an autoantibody with collagen type I specificity.

Aged↗

PubMed1986

Identification and quantification of a monoclonal IgM euglobulin: pitfalls and methodologic instruction.

In a patient with Waldenström's macroglobulinemia routine agarose gel electrophoresis and immunofixation disclosed an IgM-kappa M-component with beta-mobility, but failed to unveil a major monoclonal IgM-kappa euglobulin. This, however, was demonstrated when the procedures were performed in a buffer with NaCl-ion-strength of 0.1 M. Similarly, IgM quantification by routine nephelometry and electroimmunoassay led to dramatically inconsistent results. By a simple agarose gel electrophoresis in NaCl 0.1 M the IgM euglobulin was quantified proportional to the serum concentration of albumin. The identification and classification of an M-component, being exceedingly important diagnostically, may be missed, when solely routine electrophoresis and immunofixation is employed. As regards the quantification of M-components, these are not merely pathologic immunoglobulins nosologically. Also, biochemically they differ from normal, polyclonal immunoglobulins, resulting in immunological techniques being inapplicable for their quantification. For quantitative purposes, a simple, comparative agarose gel electrophoresis is described.

Aged↗

PubMed1985

Differentiation between metaplastic carcinomas and sarcomas of the human female breast by fibronectin.

The distribution pattern of fibronectin in metaplastic carcinomas, stromal sarcomas, malignant cystosarcoma phyllodes tumours and histiocytic type lymphomas of the human female breast has been studied using the indirect immunoperoxidase technique on formalin fixed paraffin embedded tissue. Fibronectin was demonstrated as intensely stained strands between tumour cells forming an irregular network in metaplastic carcinomas and lymphomas. Stromal sarcomas and the malignant stromal component of the phyllodes tumours exhibited, in contrast, a uniform staining throughout tumour cells and stroma which was weaker than in adjacent normal-looking connective tissue. We suggest that the intense staining reaction of metaplastic carcinomas is due to the scirrhous reaction generally associated with invasive human breast carcinomas. The advantage of using fibronectin as a diagnostic tool in the differentiation of carcinoma/lymphoma versus sarcoma is the fact that the antigen is a stromal marker and its staining intensity is not influenced by the morphology or degree of differentiation of non-mesenchymal tumours.

Breast Neoplasms↗

PubMed1985

In vivo demonstration of cytoplasmic fibronectin in human breast carcinomas.

The distribution pattern of fibronectin in 24 invasive human breast carcinomas has been studied using the indirect immunoperoxidase technique. A positive cytoplasmic staining reaction was observed in 16 tumours. Well-differentiated carcinomas showed weak or no staining, whereas all moderately or poorly differentiated carcinomas and one signet ring cell carcinoma contained fibronectin positive tumour cells with moderate or strong staining. The staining intensity was positively correlated to degree of anaplasia with the exception of two moderately differentiated duct carcinomas and the two medullary carcinomas, which were only slightly positive. Non-attached independently growing tumour cells stained more intensely than tumour cells in clusters. Pericellular fibronectin was found in only one carcinoma of medullary type. In normal ducts and glands it was seen at the stromal-epithelial junction corresponding to the basement membrane, around myoepithelial cells and along the luminal border. The results support the findings of several in vitro investigations that breast tumour cells synthesize fibronectin. It also suggests that cytoplasmic fibronectin expression might be an indicator of tissue differentiation in non-solidly growing invasive duct carcinomas of the human mammary gland.

Breast Neoplasms↗

PubMed1985

Immunization of mice with the fibronectin-binding protein and clumping factor from Staphylococcus aureus: antibody response and resistance against intraperitoneal infection.

The antibody response against Staphylococcus aureus antigens was quantitated in mice immunized with live staphylococci, the fibronectin-binding protein, clumping factor, or saline by means of enzyme-linked immunosorbent assay. Immunization with purified clumping factor induced a significant increase in antibody levels, while the fibronectin-binding protein gave a poor response. All mice immunized with live S. aureus developed a high antibody level. The immunization of mice with live S. aureus or clumping factor resulted in an increased resistance towards staphylococcal intraperitoneal infection.

Animals↗

PubMed1985

Isolation of Staphylococcus aureus clumping factor.

Immunochemically identical components were isolated from water-soluble phases of five Staphylococcus aureus strains by affinity chromatography on fibrinogen-linked Sepharose 4B. The elution was performed with 1 M MgCl2. The component could be isolated from sonicated preparations of whole cells, cell walls, and extracellular products of S. aureus but not from sonicated preparations of staphylococcal L-forms or from Staphylococcus epidermidis. Investigations of the eluted component by immunoelectrophoresis and Western blot analysis by use of different polyspecific antibodies to S. aureus raised in rabbits revealed only one immunoprecipitate or one band. By means of gel filtration on Sepharose CL 6B and sodium dodecyl sulfate-polyacrylamide gel electrophoresis a molecular mass of 420,000 and 360,000 was found, respectively. Chemical analysis showed a carbohydrate content of about 20% by weight. By crossed immunoelectrophoresis the isolated component was demonstrated to bind to human fibrinogen. The finding that this purified component inhibited the fibrinogen-induced clumping of staphylococci strongly suggests that the component is the S. aureus clumping factor.

Animals↗

PubMed1984

Sequential appearance of fibronectin and collagen fibres in experimental arthritis in rabbits.

The sequential changes in the presence of fibronectin in the synovial membrane during the development of antigen-induced arthritis in rabbits were studied using an indirect immunoperoxidase technique on the tissue specimens fixed in formaldehyde, embedded in paraffin and pre-treated with pepsin and testicular hyaluronidase. The relation to the distribution of fibronectin and connective tissue fibres, demonstrated as either argyrophilic or red by van Gieson method, was studied. Initial after the induction of the arthritis the synoviocytes became increased in size and number. The subsynoviocytial tissue was invaded by granulocytes and the number of vessels was increased. Fibronectin in increased amount was seen around the lining cells. After 2-4 weeks a markedly reduced amount of granulocytes were seen together with an increase in the number of macrophages. At this stage, fibronectin was also found together with argyrophilic fibres in the subsynoviocytial connective tissue. After 8-13 weeks the synovial membrane was found hypertrophic and folded. The lining layer was unchanged, but in the subsynoviocytial tissue lymphocytes and plasma cells were more focally arranged. At that time fine fibres, stained by the van Gieson method, were present together with fibronectin and argyrophilic fibres in the subsynoviocytial tissue. The morphological change and the distribution of fibronectin in experimentally induced arthritis correlated temporally to the morphological change and the presence of fibronectin found in experimentally induced granulation tissue.

Animals↗

PubMed1984

Rheumatoid nodules. A lightmicroscopical study with special reference to fibrin and fibronectin.

The presence and localization of fibrin and fibronectin in rheumatoid nodules were studied using an indirect immunoperoxidase technique on tissue specimens fixed in formaldehyde, embedded in paraffin and pretreated with pepsin and testicular hyaluronidase. Three zones characteristic for rheumatoid nodules was recognized. Central area with necrosis, containing at least in part fibrinogen-antigenic material and fibronectin especially in the peripheral part of the necrotic area. Around the necrosis a layer of mesenchymal cells in a palisade arrangement was found. Especially in the external part of this layer fibronectin was demonstrated around and between the cells, where fibrin was absent. Peripherally, a zone of non-specific granulation tissue containing moderate amount of fibronectin decreasing towards the surround mature connective tissue, was seen. In the border of the cellular layer vessels were found in variable amount. In some of the vessels vasculitis was demonstrated with the presence of inflammatory cell infiltration, fibrin deposition and occasionally thrombosis. The pathogenesis of the inflammatory reaction in rheumatoid nodules is discussed.

Adult↗

PubMed1984

Opsonic activity of fibronectin in the phagocytosis of Staphylococcus aureus by polymorphonuclear leukocytes.

The effect of the opsonic activity of human purified fibronectin on phagocytosis of Staphylococcus aureus by human polymorphonuclear leukocytes was investigated. After opsonization with fibronectin there was a significant increase in the rate of phagocytosis of four out of six Staphylococcus aureus strains. Both attachment to and ingestion by leukocytes was affected, as revealed by lysostaphin treatment. Incubation of leukocytes with fibronectin prior to phagocytosis did not enhance the phagocytosis of Staphylococcus aureus. This shows that the observed enhancement of phagocytosis was dependent on the binding of fibronectin to Staphylococcus aureus. The ability of fibronectin to opsonize different strains of Staphylococcus aureus varied with the strain. A variation was also observed in fibronectin-induced phagocytosis by leukocytes from different donors.

Blood Bactericidal Activity↗

PubMed1984

Plasma fibronectin concentrations in patients with severe burn injury.

Plasma fibronectin concentrations were measured in 33 patients with major burn injury. Changes in plasma fibronectin concentration were related to the day of burn injury, surgery and to the development of sepsis. Within 24 hours of the burn injury and surgical treatment, a decrease of the plasma fibronectin concentration was observed, which returned to normal values within 72 hours. A decrease in the plasma fibronectin concentration was observed as sepsis developed, while recovery from septicaemia was associated with plasma fibronectin concentration returning to normal values.

Adolescent↗

PubMed1984

Immunochemical studies on an IgG lambda cryoglobulin in cold-induced urticaria.

A type I cryoglobulinaemia associated with cold-induced urticaria was demonstrated in a 64-year-old woman without primary disease. The cryoglobulin contained only IgG lambda as disclosed by immunofixation technique. Different physicochemical studies indicated that the IgG lambda component was monomeric at temperatures above 35 degrees C, but became polymerized below 35 degrees C. In addition crossed immunoelectrophoresis of plasma fibronectin from the patient showed a heterogeneous precipitate at low temperatures but a homogeneous precipitate at 25 degrees C indicating a complex formation at low temperature between IgG lambda and fibronectin. Fibronectin, however, was not essential for the cold precipitation of the cryoglobulin. The precipitation phenomenon at low temperatures was found to be a result of the physicochemical properties of the cryoglobulin itself unrelated to the antibody specificities tested. The importance of performing the immunochemical and physicochemical techniques at low temperature (7 degrees C) and at high temperature (35 degrees C) to gain knowledge of the nature of the protein, is emphasized. We conclude that only results obtained by relevant laboratory procedures might lead to correct classification and understanding of cryoglobulinaemia.

Aged↗

PubMed1984

Human serum and plasma increase mouse mortality in Staphylococcus aureus intraperitoneal infection.

The influence of human plasma, serum, purified fibrinogen, and fibronectin on Staphylococcus aureus intraperitoneal infection in non-immune mice was studied. Mouse mortality was used as a measure of staphylococcal virulence. Both human plasma and serum were shown to enhance the virulence of S.aureus strain E 2371 and strain E 2476 when added to the bacteria before challenge. This effect of serum was unaffected by storage for 24 h at 37 degrees C or complement-inactivation for 1 h at 56 degrees C. Purified fibrinogen and fibronectin did not influence the S. aureus virulence. It is suggested that the effects of plasma and serum described here might play a role in the establishment of S.aureus infections in humans.

Animals↗

PubMed1984

Effect of human IgG and fibrinogen on Staphylococcus aureus intraperitoneal infection in mice.

Human serum and plasma have been demonstrated to enhance mortality in Staphylococcus aureus intraperitoneal infection in mice. Two different mechanisms seem to be involved. The effect of serum could be removed by adsorption to S. aureus protein A coupled to Sepharose 4 B and could be reconstituted by the addition of human IgG to IgG-depleted serum. Plasma diluted 1/10 in combination with purified fibrinogen also enhanced mouse mortality. Both effects could be demonstrated, when a coagulase-free variant of S. aureus was used. The results of viable counts of S. aureus in blood and peritoneum of the mice indicate that the enhancing effect of IgG alone and the enhancing effect of fibrinogen in combination with diluted plasma have different mechanisms.

Animals↗

PubMed1984

Native and degraded fibronectin: new immunological methods for distinction.

Two methods for quantitative determination of the high molecular weight glycoprotein, fibronectin, have been developed. Both methods are based on enzyme-linked immunoadsorbent (ELISA) techniques. In the first of the methods an antibody against fibronectin is used to trap the antigen. This double antibody technique can detect a slight decrease in the concentration of fibronectin stored for 5 days compared to the amount of fibronectin in the freshly purified preparation. In the second method, gelatin which is known to bind specifically to fibronectin, is used to catch fibronectin. By this method less than 1% of the fibronectin present in a freshly prepared preparation is measured after storage for 5 days. The results obtained with the two methods applied on a freshly prepared and a stored fibronectin are in agreement with sodium dodecylsulphate polyacrylamide gel electrophoresis followed by immunoblotting before and after gelatin-Sepharose adsorption. These techniques demonstrate that all the freshly prepared fibronectin adsorbs to gelatin-Sepharose, while stored fibronectin, which is broken down to numerous peptides, still reacts with the fibronectin antibody, but does not adsorb to gelatin-Sepharose. The two ELISA techniques were applied on amniotic fluid, cerebrospinal fluid and urine. The results indicated significant degradation of fibronectin in urine, and less degradation of fibronectin in amniotic and spinal fluid.

Amniotic Fluid↗

PubMed1984

Plasma fibronectin concentrations in morbidly obese patients.

Plasma fibronectin concentrations and liver morphology were investigated in 45 morbidly obese subjects (median overweight 88%) and in 42 normal weight controls, matched for sex and age. A significantly (P less than 0.01) raised plasma fibronectin concentration (median 464 mg/l, range 276-862 mg/l) was found in the obese subjects when compared with concentrations in the controls (median 348 mg/l, range 164-536 mg/l). Plasma fibronectin concentrations of the obese patients correlated significantly to their degree of overweight (r = 0.33, P less than 0.05) as well as to the degree of fatty change found in their liver biopsies (r = 0.33, P less than 0.05). Significantly (P less than 0.05) elevated plasma fibronectin concentrations even in obese subjects without hepatic fatty change indicate that liver fat accumulation is no prerequisite of the obesity-related elevation of plasma fibronectin. Raised plasma fibronectin concentration in obesity may more readily be explained by an increased fibronectin formation by lipocytes.

Adult↗

PubMed1984

Plasma and urine fibronectin concentration in kidney-transplanted patients.

Plasma and urine fibronectin concentration was determined by electroimmunoassay and ELISA-method in patients who received renal transplantation. The plasma fibronectin concentration decreased both after the transplantation, in relation to the acute rejection of the graft, and in the relation to immunosuppressive therapy. Urine fibronectin excretion increased in relation to the kidney transplantation and acute rejection of the graft. In association with improved kidney function, the urine fibronectin excretion decreased. It is suggested that it might be of clinical importance to determine the excretion of fibronectin into the urine in patients undergoing kidney transplantation.

Electrophoresis, Polyacrylamide Gel↗

PubMed1984

Significance of plasma fibronectin.

Fibronectin and fibrinogen are unique proteins, since they both are present in a soluble form in plasma and in an insoluble form in connective tissue. The insoluble fibronectin is always present in connective tissue, while the presence of fibrin is temporary. The two proteins may be associated under various conditions. Fibronectin is incorporated into polymerizing fibrin, e.g. in the tissue repair process and during thrombus formation. Fibronectin is also associated with other biological structures, such as collagen of all types, sulphated proteoglycans, blood platelets and the cell walls of Staphylococcus aureus. These properties result in a depletion of plasma fibronectin in certain clinical situations, such as disseminated intravascular coagulation (DIC), traumatic shock and severe burns. The decreased plasma fibronectin concentration might result in an increased fibrin polymer concentration in the circulation, thus accentuating the microvascular thromboses and the coagulation factor consumption in DIC. The practical clinical implication is that a low plasma concentration of fibronectin might define a group of patients with a high risk of developing DIC.

Blood Vessels↗