PubMed Health⌕ Search

Biomedical subjects

L Heickendorff

Publications and source records attributed to L Heickendorff.

At least 91 records · Page 5Linked to original sources
PubMed1989

Increased aortic stiffness in patients with type 1 (insulin-dependent) diabetes mellitus.

The biomechanical properties of aortic samples from patients with Type 1 (insulin-dependent) diabetes mellitus and age- and sex-matched control subjects were analysed using a materials testing machine. The specimens were prepared from tissue outside areas of visible atherosclerosis in order to discriminate between primary Type 1 diabetic alterations in the aortae and secondary changes due to increased atherosclerosis. We paid special attention to the correction of biomechanical parameters for differences in wall thickness and registration of specimen length values. In the Type 1 diabetic aortae a marked reduction was found in the extensibility and an increase in their stiffness. The reduced extensibility was correlated significantly to the duration of Type 1 diabetes. The pronounced alterations in the mechanical properties could not be explained by the increase in the wall thickness which was observed among the Type 1 diabetic patients and the alterations could not be correlated to the grade of atherosclerosis in the thoracic aorta. The results of the present study, therefore, strongly suggest that Type 1 diabetic patients develop alterations in the arterial connective tissue independent of the presence of atherosclerosis. Such primary alterations in the vessel wall may play a role in the pathogenesis of large vessel disease among these patients.

Aorta, Thoracic↗
PubMed1989

Serum aminoterminal propeptide of type III procollagen in progressive systemic sclerosis and localized scleroderma.

Sera from 31 patients with progressive systemic sclerosis (PSS), 5 patients with widespread localized scleroderma (LS), and 3 patients with lichen sclerosus et atrophicus were analyzed for aminoterminal propeptide of type III procollagen (PIIINP) using a radioimmunoassay based on human propeptide. Thirty-eight per cent of the patients with PSS had levels above normal range, including all of the 3 patients with diffuse scleroderma. The same applies to 4 of 5 patients with widespread localized LS, while PIIINP in all 3 patients with lichen sclerosus et atrophicus were within normal levels. In patients with acrosclerosis, elevated PIIINP seems to be correlated to rapid progression and extension of lesions. A significant increase in PIIINP was found in a patient following discontinuation of prednisone and cyclophosphamide, while the present investigation did not allow judgement of effects of treatment with either penicillamine or cyclosporin A.

Humans↗
PubMed1989

Serum aminoterminal propeptide of type III procollagen. A non-invasive test for liver fibrogenesis in methotrexate-treated psoriatics.

Serum aminoterminal propeptide of type III procollagen (PIIINP) was studied in 73 psoriatics receiving methotrexate and in 11 selected for trial with methotrexate or etretinate. 72 of the patients on methotrexate were also investigated with liver biopsies. The highest PIIINP value was found in a patient with ascites and her PIIINP decreased after medication was discontinued. Psoriatics with fibrosis or cirrhosis in their liver biopsies had a significantly higher mean PIIINP than patients without fibrosis, who had the same mean value as psoriatics prior to treatment. Based upon the individual data together with data from serial PIIINP investigations of 11 patients studied during treatment, it is concluded that PIIINP can be utilized as a valuable non-invasive test for liver fibrogenesis in methotrexate-treated psoriatics. PIIINP is not specific for the liver, but the study indicates that the number of liver biopsies can be reduced in psoriatics on methotrexate who have normal levels of PIIINP.

Biomarkers↗
PubMed1989

Quantification of fibronectin in extracts of human aortae by an ELISA.

A procedure for extraction and quantification of fibronectin in human aortic tissue is described in this paper. Dried, defatted samples of human aortic tissue were subjected to sequential extraction with (i) 0.89% NaCl, 10 mmol/l Tris/HCl, pH 7.4, (ii) 5 mg/ml heparin, 2 mol/l urea and (iii) collagenase digestion. More than 75% of hexosamine-containing molecules were solubilized by this procedure. Immunoblotting of extracted proteins separated by SDS-PAGE showed that extracted fibronectin had a mobility in the same range as that of plasma fibronectin. Fibronectin ELISA performed on these extracts gave dilution curves parallel to the standard curve, the sensitivity was 2.7 micrograms/l. Recoveries of a fibronectin standard added to the NaCl, heparin/urea and collagenase solutions during extraction were 97%, 90% and 84% respectively. Normal aortic tissue from 31 patients was subjected to the sequential extraction scheme and fibronectin quantification in the various extracts demonstrated that 4.52 +/- 1.79 micrograms was dissolved in the NaCl extracts, 5.41 +/- 2.28 in the heparin/urea extract and 1.08 +/- 0.43 in the collagenase digest, respectively. (Values are expressed as micrograms fibronectin/10 mg dry, defatted tissue (mean +/- SD]. Our results indicate that the ELISA method can be applied for the measurement of fibronectin in extracts of human aortic tissue. This might be useful in the study of diseases where alterations in arterial fibronectin content may be expected.

Aged↗
PubMed1989

Accumulation of fibronectin in aortas from diabetic patients. A quantitative immunohistochemical and biochemical study.

To obtain data concerning the pathology of diabetic arteries, aortas from 23 patients with diabetes mellitus [9 with insulin-dependent diabetes mellitus (IDDM) and 14 with non-insulin-dependent diabetes mellitus (NIDDM)] were collected at autopsy together with aortas from sex- and age-matched nondiabetic persons. A histomorphometric study was performed blindly on antifibronectin PAP-stained sections to determine the distribution of fibronectin-containing space in the vessels. In both IDDM and nonIDDM groups a statistically significant increase of approximately 45% was seen in the amount of stainable material in the tunica media. The increase was not influenced by the presence or absence of overlying plaque. No differences were seen between diabetic and nondiabetic vessels in the tunica intima. The content of extractable fibronectin in intima-media preparations was measured. The samples were extracted sequentially with buffered saline, a heparin-urea solution, and finally collagenase digestion. Fibronectin measured in these extracts showed that statistically significantly more of this glycoprotein was found in vessels from diabetic persons compared with nondiabetic persons, when comparing areas of the vessels without macroscopical visible plaque. However, only among IDDM patients increased amounts were apparent in plaque areas. These results indicate that diabetic patients develop structural alterations in the connective tissue of their arteries, consistent with a hypothesis of a diabetic macroangiopathy.

Aged↗
PubMed1988

Synthesis of factor VIII in human hepatocytes in culture.

Although several investigators have attempted to identify the site of synthesis of factor VIII (FVIII), the cellular species responsible for maintenance of plasma FVIII has not been clearly defined. Indications point at hepatocytes and certain endothelial cells. The present study investigated the FVIII coagulant antigen (VIII:Ag) of hepatocytes obtained by two-step collagenase digests of human liver pieces. Following Percoll gradient centrifugation, less than 1% of cells harvested were non-parenchymal. Lysates of freshly isolated and purified hepatocytes contained 165-250 mU of VIII:Ag/10(6) cells as defined by a two-site ELISA employing a haemophilic antibody against human FVIII. This material contained a single peak of VIII:Ag polypeptides as judged from the VIII:Ag ELISA profile of Mono-Q fast protein liquid chromatography fractions. A haemophilic antibody specific for epitopes of the light chain of FVIII, employed in immunoisolation of VIII:Ag in lysate of human hepatocytes, extracted a polypeptide pattern that was studied in a reduced SDS-PAGE electrophoresis gel and compared to that of immunoisolate from normal plasma. After electroblotting onto nitrocellulose and reaction with a monoclonal antibody towards the light chain of FVIII, the appearance of a doublet at 78-79 kDa in both these materials indicated the presence of the light chain of FVIII in human hepatocyte lysate. During culture, human hepatocytes secreted 20-80 mU of VIII:Ag per 1 x 10(6) cells per 24 hours. Further, a significant secretion of VIII:Ag was found in media of cultured human hepatoma cells, Hep-G2, whereas human blood monocytes and human fibroblasts did not secrete detectable VIII:Ag. In all of these cell cultures, vWf:Ag was indetectable or present as trace.(ABSTRACT TRUNCATED AT 250 WORDS)

Cells, Cultured↗
PubMed1988

Laminin, fibronectin and type IV collagen in BM-like material from cultured arterial smooth muscle cells.

1. The intra- and extracellular distribution of fibronectin and laminin was studied by immunofluorescence in cultures of rabbit and human arterial smooth muscle cells. 2. Basement membrane (BM)-like material was isolated from the cell layer of arterial smooth muscle cells cultures and analysed by sodium dodecyl sulphate gel electrophoresis (SDS-PAGE) and immunoblotting. The major 220-240 kD component of arterial BM-like material was identified as fibronectin. Also a 200 kD fibronectin band was observed. 3. The 200 kD subunit of laminin was contained in isolated BM-like material, but no slower migrating laminin chains were detected. 4. Collagens were prepared from pepsinized BM-like material. The band pattern as resolved by SDS-PAGE and silver staining suggested that type IV collagen is the major collagen of arterial BM-like material.

Animals↗
PubMed1988

Pathology of macrovascular disease.

In this chapter we have presented information on the development of large vessel damage in diabetes mellitus. A series of changes occur independent of the presence of atherosclerosis. The abnormalities include accumulation of PAS-positive material, laminin, fibronectin, type IV collagen and connective tissue with lack of acid mucopolysaccharides, and deposition of calcium. It is of particular interest that accumulation of PAS-positive material and lack of acid mucopolysaccharides are recognized as the histological markers of diabetic microangiopathy. These changes are in agreement with the hypothesis of a non-atherosclerotic large vessel damage, that is, diabetic macroangiopathy. From this standpoint the working hypothesis of a specific diabetic macroangiopathy should generate new ways to study the mechanism of the large vessel disease of diabetes over and above the traditional concept of classical atherosclerosis.

Animals↗
PubMed1988

Synthesis and secretion of alpha 2-macroglobulin by human hepatocytes in culture.

Hepatocytes were isolated by application of the two-step collagenase perfusion technique to pieces of human liver. The cells were incubated in serum-free medium or 10% FCS-medium supplemented with insulin, glucagon and dexamethasone, and kept in culture for more than 2 weeks. Seventy-five per cent of the medium was changed regularly and assayed for alpha 2-macroglobulin (alpha 2-M), pregnancy zone protein, alpha 1-antitrypsin and albumin by means of ELISA. Significant amounts of alpha 2-macroglobulin were present in all cultures. During incubation, alpha 2-M accumulated in the medium and the quantity of alpha 2-M released from the cells by far exceeded protein associated with hepatocytes prior to incubation. In 24 h 10(6) hepatocytes secreted 160.5 +/- 82.2 ng of alpha 2-M (mean +/- SD, n = 5). Cell-associated, as well as secreted alpha 2-M appeared to be on native form, as determined by immunoisolates from lysed cells and culture supernatants. Pregnancy zone protein was only detected in about 50% of the cultures and its rate of secretion was less than 2 ng 24 h-1 per 10(6) cells. In contrast, culture medium contained considerable quantities of alpha 1-antitrypsin and albumin. In 24 h, 10(6) hepatocytes released greater than 2 micrograms alpha 1-antitrypsin and greater than 5 micrograms albumin. The present study suggests the hepatocyte to be of major importance for the synthesis of intravascular alpha 2-M.

Adult↗
PubMed1988

Human hepatocytes in culture synthesize and secrete fibronectin.

Hepatocytes were isolated by application of the two-step collagenase perfusion technique to pieces of human liver. Hepatocytes were cultivated in serum-free medium or 10% fetal calf serum medium supplemented with insulin, glucagon and dexamethasone. The cells were kept in culture for up to 16 days and 75% of the medium was regularly changed. Fibronectin in culture medium was detected by means of an ELISA with an assay range of 2.2-560 micrograms/l. The interassay imprecision was 6.3% at 500 micrograms/l and 14.3% at 10 micrograms/l. Significant amounts of fibronectin were detected in all cultures. During culture, fibronectin accumulated in the medium and the quantity secreted by hepatocytes by far exceeded the amounts of fibronectin associated with hepatocytes prior to cultivation. Maximum secretion rate by 10(6) hepatocytes was 167.5 +/- 73.3 ng fibronectin (mean +/- SEM, n = 3) in 24 h. When analysed by means of SDS-PAGE and immunoblotting the fibronectin isolated from hepatocyte culture medium and cell lysate co-migrated with fibronectin obtained from plasma. Our data show, for the first time, that human hepatocytes synthesize and secrete fibronectin, and it is suggested that the human liver is an important source of plasma fibronectin.

Cells, Cultured↗
PubMed1987

Oligosaccharides of arterial basement membrane-like material studied on rabbit aortic myomedial cells in culture.

Oligosaccharides from myomedial basement membrane-like material were characterized in respect of size, attachment to protein and charge heterogeneity after metabolic labelling with [3H] glucosamine. Arterial basement membrane-like material was isolated from cultures of aortic myomedial cells by a sonication-differential centrifugation technique. Glycopeptides were then obtained by proteinase digestion and Sephadex G-50 chromatography. Alkaline borohydride treatment of the glycopeptides followed by Sephadex G-25 chromatography revealed that 10-14% of the oligosaccharides were released by a beta-eliminative reaction. The molecular weight of the alkali labile carbohydrate units was estimated to be approximately 750. Alkali stable oligosaccharides were released from the glycopeptides by hydrazinolysis. The liberated oligosaccharides were retarded by Sephadex G-50 chromatography corresponding to a molecular weight of 2700 using unit B thyroglobulin oligosaccharides as standard. The chromatographic pattern obtained by anion exchange chromatography of the glycopeptides after neuraminidase treatment showed that a major part of the glycopeptides contain one or more sialic acid residues, but also other negatively charged groups--possibly phosphomannosyl residues were present as suggested by [32PO4(3-)] labelling and concanavalin-A-Sepharose chromatography. Concanavalin-A-Sepharose chromatography combined with alpha- mannosidase treatment and gel filtration suggested that a minor part of the glycopeptides were of high-mannose- type.

Animals↗
PubMed1987

Insulin, ketones, glucose and glucagon: effects on the arterial basement membrane in vitro.

The influence of insulin in physiological concentrations on basement membrane (BM)-like material from arterial smooth muscle cells was studied in cell cultures. BM-like material was isolated from the cell layer by a sonication-differential centrifugation technique after a 24-h incubation period with insulin and [3H]leucine added to the culture medium. Insulin in concentrations of 50, 100, 200 and 500 mU/l was found to exert no influence on incorporation of amino acids into BM-like material. Neither glucose, 16 mmol/l, ketones, 1 mmol/l, nor glucagon 100 ng/l were able to induce altered accumulation of BM-like material. The effect of insulin on the carbohydrate units of BM-like material was studied by concanavalin A-Sepharose chromatography of glycopeptides and by analyses of neutral hexoses and amino sugars. The result showed that insulin, 200 mU/l, induced a shift in composition of neutral sugars by decreasing the amount of galactose relative to glucose and mannose. No changes in glycopeptide binding to the concanavalin A-sepharose column were observed. The results indicate that insulin induces only minor alterations in BM-like material of arterial smooth muscle cells and that the changes apparently are restricted to the carbohydrate units.

Amino Acids↗
PubMed1986

Increased degradation of carbohydrate deficient arterial basement membrane-like material from 2-deoxyglucose modified myomedial cell cultures.

The effect of 1.6 mM 2-deoxyglucose on the incorporation of [3H]leucine, [3H]glucosamine and [35S]sulphate into arterial basement membrane-like (BM) material was evaluated. BM-like material was isolated from the cell-matrix layer of cultured arterial smooth muscle cells by a sonication-differential centrifugation technique. 1.6 mM 2-deoxyglucose inhibited the 24 hr incorporation of [3H]glucosamine into BM-like material by 46% with a reduction in both [3H]glucosamine labelled glycopeptides and glycosaminoglycans. A marked decrease in [35S]sulphate incorporation (reduced by 80%) was demonstrated suggesting that 2-deoxyglucose may affect sulphatation of glycosaminoglycans. At 1.6 mM 2-deoxyglucose no effect on [3H]leucine incorporation was found. By gel filtration on Bio-Gel P6 a heterogeneous mixture of shortened glycopeptides was found after 2-deoxyglucose. The electrophoretic mobility of fibronectin and other glycoprotein components of BM-like material was increased. The stability of carbohydrate deficient BM-like material against removal/degradation was evaluated. A significantly increased removal of [3H]leucine from insufficiently glycosylated BM-like material was observed after a 24 hr chase period. The increased removal/degradation of BM-like material formed in the presence of 2-deoxyglucose was found to be a cellular dependent event.

Animals↗
PubMed1985

Growth hormone effect on accumulation of arterial basement membrane-like material studied on rabbit aortic myomedial cell cultures.

The effect of human growth hormone on arterial basement membrane-like (BM) material was studied. BM-like material was obtained from the cell layer of cultured aortic myomedial cells using a sonication-differential centrifugation technique. After the addition of small amounts of growth hormone (1 ng/ml) to the cultures, we observed a 26% increased incorporation of amino acids into BM-like material (2p less than 0.005). However, further increase in the incorporation was not observed using either 3 ng or 10 ng growth hormone per ml. Growth hormone inhibited removal/degradation of BM-like material by 16% (2p less than 0.01). However, pinocytosis rate and activity of major lysosomal enzymes: cathepsin D, acid phosphatase and beta-N-acetyl-glucosaminidase were unchanged. Incorporation of glycosaminoglycans as evaluated by [35SO4]-labelling was reduced by 8% when cells were exposed to growth hormone (2p less than 0.01). The present study demonstrates an effect of growth hormone on the turnover and composition of BM-like material in cultured arterial myomedial cells.

Amino Acids↗
PubMed1984

Glycosaminoglycans of arterial basement membrane-like material from cultured rabbit aortic myomedial cells.

Arterial basement membrane-like material was prepared by a sonication-differential centrifugation technique from cultures of rabbit aortic myomedial cells after metabolic labelling with [35S]sulphate and [3H]glucosamine. Labelled glycosaminoglycans were obtained from isolated basement membrane-like material by proteinase digestion and gel filtration. Glycosaminoglycans were identified by a combination of Sephadex G-50 chromatography and sequential degradation with nitrous acid, Streptomyces hyaluronidase, testicular hyaluronidase and chondroitinase ABC. The data showed that heparan sulphate and chondroitin sulphate were the predominant glycosaminoglycans of myomedial basement membrane-like material. Heparan sulphate accounted for about 55% of [3H]glucosamine-labelled glycosaminoglycans. In addition small amounts of hyaluronic acid was present. Only trace amounts of dermatan sulphate was found. The glycosaminoglycans were analysed by DEAE-cellulose chromatography. Two major peaks were found in the chromatogram consistent with the predominance of heparan sulphate and chondroitin sulphate.

Animals↗
PubMed1983

The carbohydrate components of arterial basement-membrane-like material. Studies on rabbit aortic myomedial cells in culture.

The carbohydrate composition of arterial basement-membrane-like material was investigated. Basement-membrane-like material was isolated from cultures of aortic myomedial cells by a sonication/differential-centrifugation technique. Purified basement-membrane-like material contained a total of 5% sugars, comprising glucose, galactose, mannose, fucose, sialic acid, glucosamine and galactosamine in the approximate molar proportions 3.2:3.5:3.4:3.2:1:5.5:3.1. In addition, small amounts of xylose were found. Analyses for uronic acid showed that glycosaminoglycans comprised about 1% of isolated basement-membrane-like material. The carbohydrate composition indicated the presence of complex-type oligosaccharides in addition to hydroxylysine-linked disaccharides. [3H]Glucosamine-labelled glycopeptides obtained by proteinase digestion and gel filtration were resistant to endo-beta-N-acetylglucosaminidase D, but more than 10% were susceptible to alpha-mannosidase, demonstrating the presence of high-mannose-type oligosaccharides. The distribution of carbohydrates among peptides of basement-membrane-like material on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis was investigated after labelling with [3H]mannose, [3H]fucose, [3H]galactose and [3H]glucosamine. Among peptides that appeared to carry carbohydrates were a proteoglycan(s) and seven glycoproteins in the molecular-weight range 120 000-700 000.

Animals↗