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Biomedical subjects

C M Lapiere

Publications and source records attributed to C M Lapiere.

At least 37 records · Page 2Linked to original sources
PubMed1988

Antagonistic effects of laminin and fibronectin in cell-to-cell and cell-to-matrix interactions in MCF-7 cultures.

During morphogenesis, tumor progression and metastasis, cell adhesion, dissociation, and migration result from a complex balance between cell-to-cell and cell-to-matrix interactions. Two different organization patterns of MCF-7 cells were induced by different extracellular matrix proteins. When plated on plastic or polymeric type I collagen gel used as a model of interstitial matrix, MCF-7 cells spread and grew in monolayer. When cultured on a solid gel of basement membrane (BM) proteins (85% laminin) used as a model of BM, cells formed clusters attached to the matrix. Matrix proteins regulated these two types of cell organization by preferentially promoting cell-to-cell or cell-support interactions. On plastic in the presence of soluble laminin or on laminin-coated dishes, cells also formed clusters. Addition of soluble fibronectin induced spreading of the cells, suggesting that laminin and fibronectin have competitive antagonistic effects on MCF-7 cell morphology. Antilaminin antibodies inhibited cluster formation and attachment, emphasizing the important role of this glycoprotein not only in promoting cluster attachment but also in cell-to-cell contact formation. Such effects of extracellular matrix proteins could play significant roles in tumor progression and metastasis.

Breast Neoplasms↗
PubMed1988

Laminin and type III procollagen peptide in human preovulatory follicular fluid.

The levels of laminin P1 fragment, a marker of basement membrane, and of the aminoterminal sequence of type III procollagen, a marker of interstitial connective tissue, were measured in human preovulatory follicular fluids. The concentrations of these peptides correlated with progesterone levels but not with those of estradiol or testosterone. Immunocytochemical studies confirmed the remodeling of the perifollicular basement membrane and interstitial matrix during oocyte maturation. The studies suggest that monitoring of the ovarian connective tissue macromolecules could be useful for estimating follicular maturation.

Basement Membrane↗
PubMed1988

Fibroblasts induce the assembly of the macromolecules of the basement membrane.

The mechanism regulating the deposition of basement membrane components (BMCs) in a polymeric structure at the junction with the connective tissues is not yet understood. Cultures and cocultures of epithelial BMC-producing cells (L2 or PER cells) and fibroblasts were prepared in several experimental conditions and the organization of BMCs was studied by immunofluorescence. The pattern of BMCs in pure cultures of L2 or pulmonary epithelial rat (PER) cells consisted of intra- and extracellular granular deposits. At very high density, the cell contours were also underlined by a disrupted network of BMC deposits. A different fibrillar plexus--containing laminin, collagen type IV, and heparan-sulfate proteoglycan resistant to deoxycholate treatment and distant from the cell membrane--was observed in cocultures of L2 or PER cells with fibroblasts. Fibrils of fibronectin and/or collagen type I were most often dissociated from this plexus of BMCs. Similar results were obtained by adding a conditioned medium of L2 or PER cells to confluent fibroblasts, even when the cells were killed. Pure laminin also bound to the fibroblast layer. A coated film of fibronectin or polymeric collagen type I was unable to bind BMC provided by a conditioned medium. It is suggested that molecule(s) synthesized by fibroblasts and deposited in the pericellular matrix are involved in the assembly of BMCs.

Animals↗
PubMed1988

Effect of EGF on human skin fibroblasts is modulated by the extracellular matrix.

The aim of this work was to clarify the reason why a discrepancy exists between the effects of epidermal growth factor (EGF) on fibroblasts in culture repressing collagen biosynthesis and in vivo stimulating wound healing. The effect of EGF on the biosynthetic activity of fibroblasts was measured in various conditions of cultures: on plastic, on plastic coated with various macromolecules of the extracellular matrix, on top of a type I collagen gel, and within a three-dimensional collagen lattice. While the noncollagen protein (NCP) synthesis was not affected by the interactions of the cell with the various coated matrices, collagen synthesis was inhibited. At the surface of a collagen gel, protein synthesis was reduced, while collagen synthesis and degradation were slightly stimulated. When embedded in a lattice, the overall biosynthetic activity of fibroblasts was largely depressed. The addition of EGF to cultures on plastic and on the various coated macromolecules resulted in a further repression of collagen synthesis while cell multiplication was slightly stimulated. On the contrary, the addition of EGF to fibroblasts in a collagen lattice resulted in a stimulation of both NCP and collagen synthesis as observed in vivo. These opposite effects of EGF in a two- or three-dimensional culture system are not related to modification in number or affinity of the EGF receptors at the cell surface. These results further support the similarity in the state of differentiation of fibroblasts in a three-dimensional lattice and in vivo.

Adolescent↗
PubMed1986

Bone remodeling during the development of osteoporosis in paraplegia.

Osteoporosis developing during the first weeks after the onset of traumatic paraplegia was studied with cortical and cancellous samples of iliac crest and tibia of 14 patients, and compared to normals. We used a procedure of bone particle fractionation (according to degree of mineralization) that allowed us to establish a profile reflecting the metabolic remodeling of bone and to analyze the organic matrix of the newly synthesized tissue. In paraplegics, we observed a large increase in the proportion of little calcified bone in the cortical as well as in the cancellous bone. Based on amino acid analyses, we found a decreased number of hydroxyproline residues in the newly synthesized organic matrix from paraplegia bone resulting either from an alteration of the prolyl hydroxylation or from the presence of an excess of noncollagen polypeptides. These results, together with previously published data reporting increased urinary hydroxyproline and calcium kinetic parameters, suggest an enhanced rate of skeletal remodeling in acute paraplegia. When investigated 2 years after injury, the patterns of distribution approach that of normal subjects.

Adolescent↗
PubMed1986

Antibodies to laminin in preeclampsia.

Laminin is a large basement membrane glycoprotein localized in the trophoblast, glomerular basement membrane and in the mesangial matrix of human glomeruli. It promotes the attachment of epithelial cells to basement membrane collagen. We have found that 14 sera from 52 patients with severe preeclampsia or eclampsia contain IgG and IgM antibodies which react with placental and kidney basement membranes. These antibodies were specific for laminin and did not react with other basement membrane proteins. They were able to fix complement. They have been demonstrated by radial immunodiffusion, radioimmunoassay and immunofluorescence blocking studies. In primary cultures they were shown to impair the attachment of trophoblast cells to basement membrane collagen. High levels of circulating immune complexes were detected only in sera from preeclamptic patients with circulating antibodies to laminin. The auto-antibodies to laminin could play a major role in the pathogenesis of severe preeclampsia by impairing the attachment of trophoblast cells to placental basement membranes and by fixation to the glomerular basement membranes and mesangial matrix.

Antibody Specificity↗
PubMed1986

Contraction of collagen lattices by fibroblasts from patients and animals with heritable disorders of connective tissue.

Fibroblasts derived from patients and animals presenting various heritable connective tissue disorders were investigated for the ability to retract a reconstituted collagen matrix. When seeded into gels, dermatosparactic calf and sheep fibroblasts did not exhibit the elongated shape of normal fibroblasts and did not contract the collagen lattice to the same extent as control fibroblasts. In contrast, several cell strains obtained from patients with Ehlers-Danlos syndrome type VII displayed contractile properties for collagen gels similar to controls. Delayed contraction was noted by two strains of fibroblasts from patients with Ehlers-Danlos syndrome type IV, whereas fibroblasts from patients with osteogenesis imperfecta, Marfan syndrome and cutis laxa had normal retraction properties.

Adult↗
PubMed1985

Nevi of connective tissue. A reappraisal of their classification.

Nevi of connective tissue may be conveniently divided according to clinical and pathologic presentations into two types, namely, the adventitial and the reticular. Nevi of adventitial connective tissue are usually small and situated on the extremities. They are characterized by accumulations of fibroblasts and apposition of collagen around adnexa and vessels. Nevi of reticular connective tissue are usually situated on the trunk. They consist of faulty distributions and amounts of collagen bundles, elastic fibers, or proteoglycans.

Collagen↗
PubMed1985

Proliferation and hyperplasia of vascular endothelium in human skin.

In a number of diseases of the skin, proliferation of endothelial cells is altered. Replication of endothelial cells has been evaluated by incorporating tritiated thymidine, and compared in inflammatory and neoplastic disorders. An attempt at pathogenic classification is proposed.

Biopsy↗
PubMed1984

Radioimmunoassay for the amino-terminal sequences of type III procollagen in human body fluids measuring fragmented precursor sequences.

Antisera specifically directed against the amino-terminal precursor sequence of bovine p-N-collagen type III (Col 1-3 III) have been raised in rabbit. When tested in a radioimmunoassay, parallel displacement curves and complete cross-reactivity were observed between bovine and human purified Col 1-3 III. However, these displacement curves were not parallel to that obtained with serially diluted human sera which presented a smoother slope. Cleavage of the Col 1-3 III peptide by collagenase at high temperature yielded an immunoreactive preparation containing two smaller peptides (Col 1 plus Col 2) III. The displacement curves obtained with human or bovine (Col 1 plus Col 2) preparations were parallel to those obtained with serially diluted human sera or other human body fluids (amniotic and ascitic fluids). Quantitative measurements of the circulating antigen in normal and pathological conditions are possible only when the (Col 1 plus Col 2) is used as standard antigen. This radioimmunoassay represents an original and simple technique offering good accuracy. The amount of (Col 1 plus Col 2) III in human adults is 69.1 +/- 27.7 ng/ml, with a distribution of frequency close to the normal. It is increased in liver cirrhosis and other conditions characterized by an active neoformation of connective tissue.

Adult↗
PubMed1984

Pathogenesis of ulcerations in deficiency of prolidase. The role of angiopathy and of deposits of amyloid.

The structure of the skin and the pattern of alteration in chronic ulcerations associated with deficiency of prolidase have been studied superficially in the past. We examined histologically several biopsies taken from apparently normal skin and from ulcerations afflicting a young woman with such a syndrome. Deposits of amyloid were found within the walls of medium-sized vessels and occasionally occluding their lumens. Impaired cutaneous microcirculation resulting from statis, moderate vasculitis, and abnormal structure of the dermis may be responsible for the regional preponderance of deposits of amyloid and ulcerations in the legs.

Adult↗
PubMed1984

Immunohistologic and ultrastructural study of the sclerotic skin in chronic graft-versus-host disease in man.

Thirteen skin biopsies were performed on 8 patients at different stages of skin sclerosis in chronic graft-versus-host disease (GVHD). On the same skin biopsies an immunostaining with antibodies directed against Types I and III procollagen, Types I, III, IV, V collagen, and laminin, and an ultrastructural study were performed. Alterations were observed at the dermal-epidermal junction and in the superficial dermis with a large deposit on Type III procollagen in the incipient scleroses and of Type I procollagen in the oldest ones. In this sclerotic superficial dermis, collagen fibers of irregular diameter were associated with mast cells and active fibroblasts, macrophages, and lymphocytes in close contact. The skin sclerosis in chronic GVHD might be considered a form of cutaneous fibrosis with features of excessive tissue repair related to an immunologic reaction between lymphocytes of the graft and tissue host cells.

Adolescent↗
PubMed1983

Characterization of oligosaccharide units of p-N-collagen type III from dermatosparactic bovine skin.

p-N-collagen type III was extracted from dermatosparactic and normal fetal bovine skin and purified by ion-exchange chromatography using DEAE- and CM-cellulose. Asparagine-linked sugar chains were fractionated by high voltage paper chromatography from the products obtained after hydrazinolysis and reduction with NaB3H4. These oligosaccharides composed of neutral and acidic components are mannose-containing oligosugars of the complex type. Their abundance is much higher in dermatosparactic p-N-collagen type III.

Animals↗
PubMed1983

Immunohistochemical localization of laminin, type IV and type V collagen in basal cell carcinoma.

Laminin, type IV and type V collagen were localized in twenty-five basal cell carcinomas (BCCs) by immunofluorescence. All basal cell carcinomas were separated from the connective tissue by a continuous basement membrane (BM) which always contained the three antigenic determinants. Nodular and cystic BCCs, but not pagetoid BCCs, contain linear and globular deposits of these BM components. The linear deposits probably represent BM debris that remains undigested and the globular deposits correspond to residual cytoplasmic fragments occurring during apoptosis. These results suggest that BM components are synthesized by epithelial cells and are secreted to polymerize at the dermo-epidermal junction.

Aged↗
PubMed1983

Accumulation of several basement membrane proteins in glomeruli of patients with preeclampsia and other hypertensive syndromes of pregnancy. Possible role of renal prostaglandins and fibronectin.

The glomerular lesions of preeclampsia consist of swelling of endothelial cells, interposition of mesangial cells and matrix between the endothelial cells and the glomerular basement membrane, and organization of subendothelial deposits of incompletely characterized material. Fibrin and immunoglobulins have previously been localized to these deposits. Laminin, a large basement membrane glycoprotein, type IV collagen, fibronectin, and a basement membrane proteoglycan were found in moderate amounts in the mesangium and prominently in the thickened glomerular capillary walls of patients with preeclampsia or other hypertensive syndromes of pregnancy. Fibrin showed the same pattern of distribution as that of fibronectin. The material deposited in the subendothelial layer of the capillary loops thus consists not only of plasma-derived proteins but also structural components of the glomerular basement membrane and of the mesangial matrix. Type I collagen deposits were demonstrated only in mesangium of pregnant patients with chronic or recurrent hypertension. Glomerular epithelial and mesangial cells synthesize in vitro the basement membrane proteins that accumulate in glomeruli of pregnant hypertensive patients. We have tested the influence of some of the pathophysiologic changes occurring during preeclampsia on the biosynthesis of collagen by rat glomerular epithelial and mesangial cells. Addition of indomethacin to the cultures transiently inhibited the synthesis of prostaglandins (PGE2) and of collagen. Addition of exogenous fibronectin to the media stimulated the production of collagen by mesangial and epithelial cells. Alterations in the metabolism of prostaglandins and the increased deposition of fibronectin observed during preeclampsia could thus play a pathogenic role in the accumulation of basement membrane proteins in glomeruli of these patients.

Basement Membrane↗
PubMed1982

A comparative study between interdermal tests with phytohemagglutinin and delayed hypersensitivity reactions elicited by tuberculin.

Intradermal (i.d.) tests with phytohemagglutinin (PHA) and tuberculin are used in clinical practice to evaluate the cell-mediated immunity. The biologic significance of the skin response to PHA, clinically evaluated by the extent of erythema and induration, was studied histologically after incorporation of tritiated thymidine. It was compared to tuberculin tests. The rate of recruitment and the respective amount of inflammatory cells varied between patients and in time. In PHA tests the inflammatory reaction occurred in two phases, the first one consisting in the predominance of polymorphonuclears, the second one being characterized by chemotactism of lymphoblasts many of which synthesized DNA. The "in vivo" reaction to PHA is therefore complex; the same clinical evaluation corresponds to markedly different stages and events in the biological reaction. The histological grading of the PHA test is therefore desirable in the evaluation of the cell-mediated immunity because only the blastic proliferation is of importance in its rating and not the edema and the accumulation of polymorphonuclears.

Chemotaxis, Leukocyte↗