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Biomedical subjects

J Risteli

Publications and source records attributed to J Risteli.

At least 235 records · Page 13Linked to original sources
PubMed1987

Serum aminoterminal type III procollagen peptide and the 7S domain of type IV collagen in patients with alcohol abuse. Relation to ultrastructural fibrosis in the acinar zone 3 and to serum hyaluronan.

Serum concentrations of the aminoterminal propeptide of type III procollagen and of the 7S domain of type IV collagen, presumed to reflect fibrotic activity in liver tissue, and of the glycosamonoglycan hyaluronan, were obtained from 40 alcohol abusers, at the time of liver biopsy. The serological results were related to morphological findings in liver tissue, i.e. no fibrosis, fibrosis without cirrhosis, micronodular cirrhosis and macronodular cirrhosis, and to ultrastructural indications of perisinusoidal fibrosis in the acinar zone 3. All patients with fibrosis and cirrhosis on light microscopy had elevated serum levels of the type III procollagen peptide as well as of the 7S domain of type IV collagen. However, due to a considerable overlap between the groups, no relations could be demonstrated to the severity of the fibrosis, supporting the assumption that these serological markers reflect the current fibrotic activity and not the amount of fibrotic tissue previously deposited. Among patients without fibrosis on light microscopy, a relation between the propeptide levels and ultrastructural perisinusoidal zone 3 fibrosis was observed, suggesting that type III procollagen peptide may be valuable in detecting very early liver fibrosis. A positive correlation was demonstrated between the serum concentrations of type III procollagen peptide and hyaluronan. As hyaluronan is degraded in the liver endothelial cells, it is suggested that the liver is involved, not only in the synthesis, but also in the degradation of the propeptide.

Adolescent↗
PubMed1986

Incorporation of sulphate into type III procollagen by cultured human fibroblasts. Identification of tyrosine O-sulphate.

Confluent cultures of normal human skin fibroblasts were labelled overnight with [35S]sulphate, and the incorporation of the isotope into type III procollagen, secreted into the medium, was verified by radioimmunoassay and immunoprecipitation after removing the heavily sulphated proteoglycans by anion-exchange chromatography. Type III procollagen and its pro and pN alpha chains were visualized in fluorographs of the immunoprecipitates. The labelled procollagen could be isolated by a combination of ion-exchange chromatography and gel filtration and was found to contain tyrosine O-sulphate, which was identified by thin-layer electrophoresis after Ba(OH)2 hydrolysis. The regions sulphated in the type III procollagen molecule were susceptible to pepsin digestion. Digestion with purified bacterial collagenase at +37 degrees C produced a labelled fragment that was recognized by antibodies against the aminoterminal propeptide of type III procollagen, indicating that the sulphated tyrosine residues are located either in this propeptide or in the non-helical telopeptide region of the type III collagen molecule proper. Sulphation of tyrosine residues is a new post-translational modification in procollagen, which could be involved in the regulation of the processing of type III procollagen into collagen and thus affect the formation of collagen fibres.

Cells, Cultured↗
PubMed1986

Serum markers for type IV collagen and type III procollagen in the myelofibrosis-osteomyelosclerosis syndrome and other chronic myeloproliferative disorders.

Myelofibrosis is characterized by excessive deposition of interstitial and basement membrane collagens in the bone marrow. In this study, specific radioimmunoassays for the aminoterminal propeptide of type III procollagen and for the 7S collagen domain of type IV (basement membrane) collagen were used to determine how this accumulation is reflected in serum. Of the 41 patients with chronic myeloproliferative disorders studied, the highest levels of both parameters were found in idiopathic myelofibrosis and in chronic myelogenous leukaemia associated with bone marrow fibrosis. Increasing degrees of bone marrow fibrosis were accompanied by increasing serum concentrations of both markers, except for osteomyelosclerosis, where notably low values were seen. Pathologically high values of one or both parameters were also found in a few patients with polycythaemia vera or a transitional myeloproliferative disorder. The antigens related to type III procollagen and type IV collagen correlated significantly with each other and with the leucocyte count. These parameters should provide noninvasive means for following the accumulation of interstitial and basement membrane collagens in the bone marrow.

Adult↗
PubMed1986

Fibrotic process and drug metabolism in alcoholic liver disease.

The effect of fibrosis on drug metabolism in alcoholic liver disease was evaluated in a comparison of the concentrations of serum aminoterminal propeptide of type III procollagen and basement membrane (BM; 7S domain of type IV collagen and laminin) antigens with in vitro (cytochrome P-450) and in vivo (antipyrine) drug metabolism in 67 alcoholics classified by liver histology. Alcoholics with intact or fatty liver had rapid or normal drug metabolism and normal collagen metabolism. Alcoholics with a fatty liver plus fibrosis or active cirrhosis had reduced drug metabolism and elevated levels of serum markers for collagen and BM metabolism. Alcoholics with inactive cirrhosis who had received therapy with enzyme inducers had a tendency toward normal drug and collagen metabolism parameters. Antipyrine metabolism, but not P-450 content, was related to the levels of serum type III collagen and BM markers. The fibrotic process, especially BM formation, creates a mechanical barrier that may prevent contact between blood and hepatocytes, thus delaying substrate availability.

Adult↗
PubMed1986

Effect of age and diabetes on type IV collagen and laminin in human kidney cortex.

Specific radioimmunoassays for the 7-S domain of type IV collagen and the fragment P1 of laminin were used to quantify these basement membrane proteins in human kidney cortex at different ages and in some patients with diabetes mellitus. The antigens were solubilized by treating the tissue samples with the proteolytic enzymes collagenase, trypsin and pepsin. Total collagen content (as indicated by hydroxyproline concentration) increased with age, and the proportion of the collagen that could be solubilized by any enzyme treatment decreased. The type IV collagen concentration increased significantly with age, whereas the laminin concentration tended to decrease. In the one case of a type I diabetic the amounts of both antigens exceeded those in the age matched controls. In four type II diabetics the results were comparable with those for other aged cases. The distribution of the proteins was studied using the peroxidase-antiperoxidase method. The staining intensity and thickness of both antigens increased with age in the mesangium and Bowmans capsules, the change in type IV collagen staining being more evident. In diabetic patients these changes were more pronounced and other basement membranes appeared thicker in the stainings. These results indicate that basement membrane material accumulates in the kidney cortex during aging and that an alteration takes place in the composition of the basement membranes, the proportion of type IV collagen increasing and that of laminin decreasing.

Adolescent↗
PubMed1986

Immunohistochemical study of basement membrane proteins and type III procollagen in myelofibrosis.

In this study the distribution of type IV collagen in the marrow is compared with that of laminin, another basement membrane protein. In addition, incompletely processed type III procollagen is identified with specific antibodies. In normal bone marrow the distribution of the type III procollagen antigen closely resembles that of reticulin staining. In all the myelofibrotic samples, representing both early and advanced disease, the fibrous tissue stains heavily for this antigen. Thus type III procollagen which has not completely lost its aminoterminal propeptide is a genuine component of the extracellular matrix fibres in human bone marrow. Laminin is found with type IV collagen in continuous basement membranes in arterial walls, whereas only discontinuous strips of staining are seen along the sinusoids in normal marrow. In myelofibrosis the dilated or obliterated sinusoids have thickened or continuous basement membranes, visible with both stainings. Neovascularization also increases the extent of basement membrane staining in fibrotic marrow. With respect of these antigens, there is no difference between primary and secondary myelofibrosis. These changes warrant the use of serum antigens related to type IV collagen and to type III procollagen as markers for developing myelofibrosis.

Adult↗
PubMed1985

Purification and characterization of the N-terminal propeptide of human type III procollagen.

The N-terminal propeptide of type III procollagen was purified from human ascitic fluid by using (NH4)2SO4 precipitation, DEAE-Sephacel chromatography at pH 8.6, Sephacryl S-300 chromatography and another DEAE-Sephacel chromatography at pH 4.5. The Mr of the human peptide was about 42 000, which corresponds in size to the propeptide released by the specific N-proteinase during the extracellular processing of collagen. Bacterial-collagenase digestion of the human peptide produced three fragments, which could be separated on a Bio-Gel P-10 column. The human propeptide and its collagenase-derived fragments, an N-terminal non-collagenous domain Col 1, a C-terminal non-helical domain Col 2 and a collagenous domain Col 3, resembled those derived from the N-terminal segment of bovine type III procollagen in their amino acid composition. The human peptide was found to contain sulphate, which may explain its extremely low isoelectric point (3.1). Antibodies against the human N-terminal propeptide reacted similarly with both the purified human peptide and a corresponding segment of bovine type III procollagen. The human propeptide could be used in developing radioimmunoassays for monitoring fibrotic processes.

Amino Acids↗
PubMed1985

Amino acid sequence of the N-terminal aggregation and cross-linking region (7S domain) of the alpha 1 (IV) chain of human basement membrane collagen.

The amino acid sequence of the 216-residue-long N-terminal aggregation and cross-linking 7S domain of the alpha 1 (IV) chain of human placental basement membrane collagen is presented. The N terminus of the alpha 1 (IV) chain starts with a non-triple-helical region, which is at least 15 residues long and contains four cysteine and two lysine residues as putative cross-linking sites. This segment is followed by a 120-residue-long triple helical region, which contains the unusual occurrence of a cysteine residue in the Xaa position of a Gly-Xaa-Yaa triplet. Since individual molecules in the 7S domain are associated in an antiparallel manner, this cysteine probably aligns with one of the four cysteines in the amino-terminal end of an adjacent molecule, forming an intermolecular disulfide bridge. The length of the overlap of two adjacent molecules is estimated to be about 110 residues. The triple helix adjacent to the overlap zone is interrupted by a 10-residue-long non-helical area, which is probably responsible for the flexible region of the molecules in the neighbourhood of the overlap zone observed in the electron microscope. The mode of aggregation of the 7S domain, the formation of intermolecular cross-links as well as the relatively high stability of this region against proteolytic attack are discussed in the light of the elucidated amino acid sequence.

Amino Acid Sequence↗
PubMed1985

Amniotic fluid laminin and type IV collagen in normal and pathological pregnancies.

Specific radioimmunoassays for the fragment P1 of human laminin and the 7-S collagen domain of human type IV collagen were used to quantify these basement membrane proteins in second trimester amniotic fluid samples from 21 normal and 41 pathological pregnancies, the latter group being defined by elevated amniotic fluid alpha-foetoprotein (AFP) or abnormal foetal karyotype, or both. The mean laminin P1 concentration in the normal 15 to 18-wk pregnancies was 36 micrograms/l (range 10-77) and that of the 7-S collagen was 46 micrograms/l (range 7-152). The molecular size of the antigens in amniotic fluid from both normal and pathological pregnancies, when assessed by gel filtration was very large, probably representing intact laminin and type IV collagen. Pathological pregnancies, e.g. cases of Turner syndrome, Meckel syndrome and anencephaly often had elevated amniotic fluid laminin and type IV collagen concentrations. A weak, but nevertheless significant, correlation was found between the amniotic fluid laminin and type IV collagen concentrations and also between type IV collagen and AFP, but none between laminin and AFP. In eight pregnancies with foetuses suffering from the congenital nephrotic syndrome of the Finnish type, a genetic disease assumed primarily to involve some component of the glomerular basement membrane, the amniotic fluid concentrations of both laminin and type IV collagen were within normal limits in spite of an elevated amniotic fluid AFP.

Amniotic Fluid↗
PubMed1985

Effects of experimental nephrosis on basement-membrane components and enzymes of collagen biosynthesis in rat kidney.

The aim of the present study was to find out whether the basement-membrane proteins laminin and type IV collagen are involved in the development of aminonucleoside-induced nephrosis. These proteins were measured by specific radioimmunoassays in serum, urine and kidney-cortex samples, and they were localized in the glomeruli by indirect immunofluorescence. Nephrosis was induced in rats with a single intraperitoneal injection of puromycin aminonucleoside. Serum laminin concentrations, detected by a radioimmunoassay for the P2 domain of the protein, increased to reach a maximum at days 5-7, and they remained elevated until at least day 14. The increase preceded the development of proteinuria, suggesting a role for laminin in glomerular function. Concomitant with proteinuria, increasing amounts of laminin antigenicity were also found in the urine. The size of the laminin antigen in serum was estimated by gel filtration, and the serum forms were found to contain both the P1 and the P2 regions of the intact laminin molecule. On the other hand, there were no changes in the serum or urinary concentrations of type-IV-collagen-derived antigens, as detected by a radioimmunoassay for the 7S collagen domain of this protein. The total content of laminin in kidney cortex, measured after digestion of the tissue with trypsin and collagenase, was, at day 9, still comparable with normal values, and the distribution of both basement-membrane proteins in the glomeruli, studied by indirect immunofluorescence, was similar to that in the controls. The tissue damage induced by aminonucleoside, however, seems to stimulate collagen biosynthesis, as the activities of prolyl 4-hydroxylase, lysyl hydroxylase and galactosylhydroxylysyl glucosyltransferase in kidney tissue increased significantly, with maxima at days 8-10.

Animals↗
PubMed1985

Characterization of the perivascular reticulin network in a case of primary brain lymphoma. Immunohistochemical demonstration of collagen types I, III, IV, and V; laminin; and fibronectin.

The character of the silver positive reticulin network was analyzed with immunofluorescence and immunoperoxidase methods in an intra vitam diagnosed case of primary brain lymphoma. The network was shown to contain connective tissue proteins rich in hexose-sugars, such as type III collagen (classical "reticulin"), basal lamina constituents type IV collagen and laminin, pericellular type V collagen, as well as fibronectin (protein involved in cell adhesion). On the other hand, very little of the fibrous type I collagen was discernible. Similarly as the silver positive network, the immunohistochemically demonstrable reticulum seemed to hold the cells in the perivascular location, and once it was broken diffuse spread into the tissue occurred. Since malignant cells of B-lymphocyte origin are not known to synthesize so-called reticulin, it is suggested that the network in primary brain lymphomas is produced by cells in the brain parenchyma (possibly pericytes or astrocytes) as a protective attempt to restrict the spread of foreign cells into the brain.

Brain↗
PubMed1985

Accumulation of laminin and type IV collagen in the kidney in congenital nephrosis.

The aim of this study was to evaluate qualitatively the occurrence of the basement membrane proteins laminin and type IV collagen in the kidneys of ten infants with congenital nephrotic syndrome of the Finnish type (CNF) aged from 3 to 23 months and to compare the results with those for age-matched controls. A slow accumulation of basement membrane (BM) material occurred in the glomerular mesangium, the peripheral capillaries, around atrophied tubules, and the renal vessels in the course of the disease. The staining pattern of accumulated material depended on the duration of the disease and subsequent renal parenchymal damage. Young CNF patients with slight morphological changes in the kidney had only focal and minimal increases in the amounts of mesangial matrix, but as the disease advanced, so the BMs of the glomerular capillaries, renal arteries, and atrophied tubules also became involved and were thicker than normal. The staining reaction was in all patients similar with antibodies against the fragment P1 of laminin and the 7-S domain of type IV collagen. The accumulation of BM material in CNF kidneys is regarded as a secondary phenomenon induced by an unknown pathogenetic defect in the metabolism of some BM component.

Basement Membrane↗
PubMed1985

Type IV collagen and laminin-related antigens in human serum in alcoholic liver disease.

The two major constituents of basement membranes are type IV collagen and laminin. Specific radioimmunoassays are described here for two structural domains of these proteins (7-S collagen and the fragment P1, respectively) that allow the related antigens to be quantified in human serum. The serum 7-S collagen antigen was uniform in size, whereas the laminin P1 antigenicity was heterogeneous. These proteins were measured in sera from sixty-three alcoholics, divided on the basis of liver histology into four groups: normal light microscopy, fatty liver, alcoholic cirrhosis with hepatitis and inactive cirrhosis. The group with cirrhosis and hepatitis had clearly elevated values in both assays, differing significantly from the others. A few pathological results were also seen in the other groups. The increases noted in 7-S collagen concentration were larger than those in laminin P1. During follow-up of a patient with cirrhosis and hepatitis the 7-S collagen level in particular seemed to reflect the course of the disease. The elevated basement membrane protein concentrations in serum may be associated with the formation of real basement membranes in the perisinusoidal space, a process known as capillarization of the sinusoids which is found during the development of liver cirrhosis.

Adult↗
PubMed1985

Laminin and type IV collagen in the human testis.

Specimens of normal human testis and biopsies from testes with Sertoli-cell-only syndrome in which the seminiferous tubules had a remarkably thickened lamina propria, were investigated immunohistochemically using specific antibodies against human laminin and human type IV collagen. In the normal testis, both laminin and type IV collagen were localized to the epithelial basement membranes and the peritubular cell layers. In addition, laminin was found in the Sertoli cells. In the pathological testis, structures representing invaginations of the tubular basement membrane were positive for both laminin and type IV collagen. The presence of laminin and type IV collagen in the myoid cell layers, and laminin in the Sertoli cells from both normal and pathological testis and its indication for the secretion of these substances by the myoid and Sertoli cells is discussed.

Biopsy↗
PubMed1985

Basement membrane laminin and type IV collagen in endometrial adenocarcinoma: relation to differentiation and treatment.

Changes in basement membrane (BM) structure were studied in functioning and hyperplastic endometrium, in adenocarcinomas with various degrees of differentiation and in progesterone-treated adenocarcinomas using electron microscopy and immunohistochemical staining with antibodies against human type IV collagen and laminin. These BM components were distinctly visualized as narrow, continuous bands beneath the epithelium and around the endometrial glands in functioning, atrophic and hyperplastic endometrium. In well-differentiated endometrial carcinomas there was mostly a continuous BM, though occasional disruptions were seen. The undifferentiated tumors, on the other hand, were characterized by the absence of a continuous BM structure, although irregular patches of BM material were found within the neoplasm. Hormonal treatment caused the reappearance of the BM structures. According to these results, the visualization of the BMs in the endometrium not only increases our understanding of tumor behavior, but can also be used as an aid for the classification and treatment of endometrial neoplasms.

Adenocarcinoma↗
PubMed1985

Basement membranes in progressing intraepithelial cervical neoplasia. An ultrastructural and immunohistochemical study with antibodies against human type IV collagen and laminin.

The occurrence and location of basement membranes (BM) and their constituents were studied in benign, inflammatory, dysplastic and malignant conditions of the uterine cervix by light and electron microscopy and by immunohistochemical analysis with antibodies against human laminin and type IV collagen. The normal squamous epithelium showed a thin subepithelial BM band, which was preserved in dysplasia. Severe inflammatory conditions affecting the epithelium caused disruption and fragmentation of the BM. Well-differentiated carcinomas were frequently surrounded by a BM, whereas anaplastic tumors had a disrupted and fragmented BM, and similar material was also seen in the tumor tissue itself. Thus the presence of a continuous BM seems to be only a relative criterion in distinguishing between benign and malignant conditions.

Basement Membrane↗
PubMed1984

Discontinuity of the basement membrane in fibrosing basocellular carcinomas and basosquamous carcinomas of the skin: an immunohistochemical study with human laminin and type IV collagen antibodies.

Thirteen basocellular carcinomas (BCC) of different histologic types and 5 basosquamous carcinomas (BSC) of the skin were stained for laminin and type IV collagen with rabbit antibodies against the human basement membrane (BM) proteins, using an immunoperoxidase technique. The BM around the tumor aggregates contained both laminin and type IV collagen, and was continuous and distinct in all the nonfibrosing BCCs but indistinct or interrupted in the fibrosing BCCs and BSCs. The BM was not influenced by the focal adnexal differentiation of the BCC cells. The disintegrity of the BM in the fibrosing BCCs and BSCs may reflect some kind of disturbance in the interaction between the neoplastic epithelium and the connective tissue stroma, and be connected with the more aggressive nature of these tumors compared with ordinary BCCs. Thus local aggressive behavior seems to be accompanied by defects in the BM.

Antibodies↗