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Biomedical subjects

L Risteli

Publications and source records attributed to L Risteli.

At least 181 records · Page 10Linked to original sources
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

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

Immunohistochemical characterization of the basement membranes of the human oral mucosa.

Type IV and V collagens, laminin and heparan sulphate proteoglycan were localized in vascular and subepithelial basement membranes. Fibronectin was distributed in a reticular pattern throughout the lamina propria under the oral epithelium. The uniform distribution of basement membrane components and type V collagen in different regions suggests a similar molecular composition for the basement membranes under functionally-different oral epithelia. The more intense reaction in the vascular than in the subepithelial basement membranes, with diluted antibodies to type IV collagen and laminin apparently reflects chemical differences in these basement membranes. Occasional discontinuities in the subepithelial basement membranes were seen in inflamed gingival sulci and in tonsillar crypts. The destruction responsible affected all basement membrane components, except fibronectin, which maintained a reticular distribution even in the deep tonsillar tissue. The immunohistochemical method is useful in demonstrating different degrees of destruction in basement membranes associated with inflammation.

Adolescent↗
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↗
PubMed1984

Basement membrane laminin and type IV collagen in various benign and malignant adnexal tumors of the skin: an immunohistochemical study.

Thirty benign and seven malignant adnexal tumors of the skin and one lymph node metastasis were stained for laminin and type IV collagen with rabbit antibodies against the human basement membrane (BM) proteins using the immunoperoxidase technique. Fifteen of the benign sweat gland, sebaceous gland, and hair follicle tumors showed a continuous and distinct BM around the tumor aggregates. The cylindromas and eccrine spiradenomas seemed to produce excessive amounts of BM material, part of which was seen as amorphic patches within the tumor cell clusters, whereas the trichofolliculomas, trichoepitheliomas, and pilomatrixomas showed an absence of BM from many areas. In syringomas, in addition to the tubular structures surrounded by a continuous BM, undifferentiated cell nests containing granular BM material were present. They probably represent primitive structures obtaining during early development into tubules. The seven malignant tumors and the only metastasis studied here all contained small, narrow strips of BM material extracellularly between the infiltrating tumor clusters. Only in two cases was faint staining for laminin found within the cells. The pepsin pretreatment of the formalin-fixed, paraffin-embedded samples had most probably degraded the intracytoplasmic BM material in most cases. The BM defects were found to be associated with malignancy and low differentiation of the adnexal skin tumors, as reported previously for other tumor types, but a partial loss of BM was also associated with high differentiation in some benign adnexal tumors.

Adenoma↗
PubMed1984

Immunohistochemical localization of epidermal basement membrane laminin and type IV collagen in bullous lesions of dermatitis herpetiformis.

Antibodies against the human basement membrane proteins, laminin and the 7-S domain of type IV collagen, were used to study the epidermal basement membrane in lesional skin from four patients with dermatitis herpetiformis. The staining pattern of both antigens was mostly fragmented and sometimes absent on papillary microabscesses, but when present it was attached to the epidermal basal cells. On papillary microblisters and larger blisters the staining of both antigens showed discontinuities and was located in the floor of the blister, except for two cases where tiny fragments of laminin staining were also seen in the roof of larger blisters. These results suggest that blister formation in dermatitis herpetiformis takes place between the epidermal basal cells and the basement membrane.

Adolescent↗
PubMed1983

Effect of the structural components of basement membranes on the attachment of teratocarcinoma-derived endodermal cells.

The effect of biochemically purified basement membrane components as mediators of cell attachment is studied in vitro using an endodermal PYS-2 cell line known to produce a basement membrane-like insoluble matrix. Fibronectin is shown to be as effective as laminin as an attachment-promoting protein, although the latter is a major product of these cells and the former is not produced by them in any detectable amount. Fibronectin also increases the attachment of the cells to type IV collagen-coated plates, but laminin lacks this effect. Protein synthesis-blocking agents such as cycloheximide totally abolish the attachment-promoting effect of extracellularly supplied laminin, but not that of extracellular fibronectin. Type IV collagen alone is no better a substratum for these cells than type I collagen or the plastic surface of the dish itself. The importance of an intact tertiary structure for the attachment is obvious in the case of both fibronectin and laminin. Denatured molecules or smaller fragments of these molecules do not promote cell attachment.

Animals↗