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C M Lapière

Publications and source records attributed to C M Lapière.

At least 37 records · Page 2Linked to original sources
PubMed1996

Activated forms of MMP2 and MMP9 in abdominal aortic aneurysms.

PURPOSE: This consistent observation of a reduction of the elastin concentration in abdominal aortic aneurysms (AAAs) has led us to investigate in AAA specimens two metalloproteinases that display elastase activity, MMP2 (gelatinase A/72kDa) and MMP9 (gelatinase B/92 kDa). METHODS: Samples of full-thickness aortic wall, adherent thrombus, and serum were collected in 10 patients with AAAs. Samples of normal aortic wall and serum were taken from 6 age-matched control patients. Quantitative gelatin-zymography and gelatinolytic soluble assays after acetyl-phenyl mercuric acid activation were performed on serum and tissue extracts, and the results were expressed in units on a comparative wet-weight basis. Histologic analysis was performed in parallel to score the inflammatory infiltrate. RESULTS: The luminal and parietal parts of the thrombus contained, respectively, 20- and 10-fold more gelantinolytic activity than the serum. The predominate form was MMP9. Although the total gelatinolytic activity was in the same range both in AAAs and in normal walls, a significantly higher proportion of MMP9 was found in the aneurysmal aortic walls. Furthermore, a significant proportion of MMP9 was under its processed active form, which was never observed in normal samples. A significantly higher proportion of MMP2 was also present as processed active form in AAA wall. This latter parameter positively correlated with the inflammatory score. CONCLUSIONS: The presence of activated MMP9 and MMP2 might contribute to the degradation of the extracellular matrix proteins that occurs during the development of aneurysms.

Aged↗
PubMed1996

Primary systemic amyloidosis. A report of 2 cases.

We report 2 cases of primary systemic amyloidosis. A monoclonal gammopathy was confirmed at the postmortem examination of the first patient. An extensive search for evidence of chronic infection, inflammation, neoplasms and paraproteinemia was conclusively negative in the other patient. The recognition of cutaneous signs of primary systemic amyloidosis is crucial to insure a rapid management aimed at postponing the fatal issue of the disease.

Aged↗
PubMed1996

[Low intensity electromagnetic fields produce a wave of calcium in the fibroblasts].

Human fibroblasts display a Ca2+ wave after irradiation with an electromagnetic field (EMF) of low intensity (100 to 900 microT) as seen by LASER confocal microscopy and excitation of Fluo 3. The number of excited cells is proportional to the intensity of EMF between 100 and 900 microT. Cellular activation by a dialysable serum factor is required to induce the Ca2+ wave. It also depends on extracellular Ca2+ and active tyrosine kinases and phospholipase C gamma.

Calcium↗
PubMed1995

Characterization and partial amino acid sequencing of a 107-kDa procollagen I N-proteinase purified by affinity chromatography on immobilized type XIV collagen.

Procollagen I N-proteinase (EC 3.4.24.14), the enzyme that specifically processes type I and type II procollagens to collagen, was isolated from extracts of fetal calf skin. After two chromatographic steps on concanavalin A-Sepharose and heparin-Sepharose, the semi-purified preparation was used to produce monoclonal antibodies. One reacting antibody was found to recognize not the enzyme itself but type XIV collagen on which the enzyme was bound. This binding, highly sensitive to ionic conditions (plH, salt concentrations) but not affected by non-ionic detergents, was used for affinity chromatography that strongly improved the purification procedure. The enzyme is extensively characterized: 1) it has a molecular mass of 107 kDa as determined by polyacrylamide gel electrophoresis in presence of SDS and of about 130 kDa when estimated by gel filtration on a Sephacryl-S300; 2) in standard assay (pH 7.5, 0.2 M NaCl, 35 degrees C), the activation energy for reaction with amino procollagen type I was 17,000 calories per mole. In the same conditions, Km and Vmax values were, respectively, 435 and 39 nM per hour but varied strongly with pH and salt concentration; 3) the enzyme cleaved the NH2-terminal propeptide of type I procollagen at the specific site, the Pro-Gln bond in the alpha 1 type I procollagen chain; 4) the enzyme contained a high proportion of Gly, Asx, and Glx residues but no Hyp or Hyl; 5) partial amino acid sequences obtained from internal peptides of the enzyme displayed no significant homology with known sequences. The association of procollagen I N-proteinase with a FACIT (fibril-associated collagens with interrupted triple helices) collagen as found here might be of physiological significance.

Amino Acid Sequence↗
PubMed1995

Investigation of the relationship between osteoporosis and the collagenase gene by means of polymorphism of the 5'upstream region of this gene.

Osteoporosis is a slowly progressing disease resulting from an imbalance between bone accretion and degradation. As interstitial collagenase is a key enzyme in the degradation of bone matrix, we investigated a possible relationship between the collagenase gene and osteoporosis. Analysis of an amplified genomic DNA fragment from -524 to +52 by denaturing gradient gel electrophoresis and sequencing allowed us to detect three dimorphic sites upstream of base -300, one of them leading to a BanI restriction site. None of the sites could be directly associated with osteoporosis. The allele frequencies of the three dimorphic sites were estimated. The interallelic ratios were high, thus providing new useful genetic markers for linkage analysis. When comparing these ratios in osteoporotic and nonosteoporotic subjects, no significant differences could be observed.

Adult↗
PubMed1995

Keratinocytes modulate the biosynthetic phenotype of dermal fibroblasts at a pretranslational level in a human skin equivalent.

In this study we investigated the influence of keratinocytes on the phenotype of fibroblasts in an in vitro human skin equivalent. Keratinocytes were seeded at the surface of fibroblast-populated mechanically restrained type I collagen gels (lattices). Lattices without keratinocytes were handled in parallel as controls. After 2 and 4 days in culture, the keratinocyte layer was removed and the steady-state level of the mRNA for the main extracellular matrix macromolecules and interstitial collagenase produced by the fibroblasts was measured by Northern and dot blot analysis. A 50% decrease in the amount of procollagen type I and type III mRNAs was observed after 2 and 4 days of coculture while collagenase gene expression was upregulated by 300% when compared with control lattices. No significant modulation of type IV and type VI collagen, elastin or laminin B1 mRNA levels was found. Fibronectin mRNA levels in fibroblasts were significantly increased only on day 4. All the observed changes could be reproduced using a conditioned medium collected from a lattice covered with keratinocytes added to a lattice containing fibroblasts alone. These results indicate that in an in vitro reconstituted skin, keratinocytes are able to modulate the biosynthetic phenotype of fibroblasts at a pretranslational level through a paracrine signalling pathway.

Adult↗
PubMed1994

Cultured myofibroblasts display a specific phenotype that differentiates them from fibroblasts and smooth muscle cells.

BACKGROUND: Myofibroblasts (MF) from human granulation tissue derive from perilesional cells and display similarities with fibroblasts (DF) and smooth muscle cells (SMC). OBJECTIVE: Determine additional markers to assess the phenotype of MF. METHODS: MF, DF and SMC derived from human tissues were amplified in culture. Their phenotype and response to various regulatory processes were compared in vitro. RESULTS: MF resemble SMC by their mechanical properties and cytoskeletal proteins. They resemble DF by their biosynthetic phenotype and their response to the regulation operated by the extracellular matrix and mechanical forces. CONCLUSION: In vitro MF display a phenotype that differentiates them from DF and SMC.

Cells, Cultured↗
PubMed1994

[Type VII C Ehlers-Danlos disease or human dermatosparaxia: the product of a fruitful union of so-called fundamental sciences with human and veterinary clinical medicine].

Ehlers-Danlos type VII C disease is a heritable disorder of the connective tissues and a disease similar to dermatosparaxia in bovine and other animal species. The determination of the pathomechanism of these diseases, the inactivity of the specific protease excising the aminoterminal extension of the type I collagen precursor, resulted of interactive basic and clinical research.

Ehlers-Danlos Syndrome↗
PubMed1994

[Anodontia and hidrotic ectodermal dysplasia, hyporeactive to heat. Effect of acitretin].

We observed an adult female patient presenting an autosomal recessive ectodermal dysplasia difficult to classify among the various reported forms of this disease. She had the major signs of the hidrotic type of the disease (palmo-plantar hyperkeratosis, nail and hair dystrophies, and typical sweat glands) and anodontia as reported in the hypohidrotic form of the syndrome. We evaluated the function of the sweat glands and found them hyporeactive to a heat stimulus. Most of the epithelial alterations have improved under therapy by acitretin.

Acitretin↗
PubMed1993

Modulation of expression of endogenous collagenase and collagen genes by electroporation: possible involvement of Ca2+ and protein kinase C.

We have investigated the effect of electroporation on the expression of collagen alpha 1(I), collagenase, c-fos and c-jun genes in human dermal fibroblasts (HDF), human smooth muscle cells (HSMC) and HeLa cells. Collagenase and collagen mRNA levels were respectively increased and decreased in a voltage-dependent manner in HDF harvested 2 days after a sham electroporation. These effects were still observed 10 days after electroporation. Similar effects occurred in electroporated HSMC. Neither collagen nor collagenase mRNAs were detected in control or electroporated HeLa cells. c-fos and c-jun mRNA levels were also increased in electroporated HDF, HSMC and HeLa cells harvested 1 h after plating. This suggests that factor AP1 (fos/jun) could mediate the up-regulation of collagenase expression in electroporated HDF and HSMC. When electroporation of HDF was performed in the presence of H7, an inhibitor of protein kinase C, no increase in collagenase mRNA level was observed, suggesting that protein kinase C might be involved in the transduction of the effect. All the effects reported were also suppressed when cells were electroporated in a medium containing EGTA, suggesting that Ca2+ might mediate the transduction of this effect.

Aluminum↗
PubMed1993

Modifications of the extracellular matrix of aneurysmal abdominal aortas as a function of their size.

Collagen and elastin are the main extracellular matrix proteins providing the aortic wall with adequate mechanical properties and resistance for proper function. Our study aimed at investigating the relationship between the elastin concentration of the wall of normal and aneurysmal abdominal aortas (AAA), the collagen concentration, and its extractability, as a function of their size. Infrarenal aortas were collected from 30 patients undergoing operative repair of abdominal aortic aneurysm. Age-matched control samples were obtained from eight autopsies of individuals without vascular disease. Samples were divided into five groups according to the aortic diameter: control group (group N, n = 8); < 50 mm (group I, n = 6; between 50-75 mm (group II, n = 10); > 75 mm (group III, n = 7); and ruptured (group IV, n = 7). The collagen concentration in samples from group I was similar to the controls. An increased collagen concentration was observed in group II and remained at the same level in the largest and ruptured aneurysms. Extractability of collagen was found to be increased in group III and was even higher in group IV. A highly significant reduction in elastin concentration was observed in group I and there was progressive reduction with increasing diameter and rupture. A significant correlation could be established between aortic diameter, increased collagen extractability and decreased elastin content.

Aged↗
PubMed1993

High-grade pleomorphic T cell lymphoma with restricted involvement of skin and bone marrow.

Pleomorphic T cell lymphoma of the medium to large cell type expressing CD30 antigen is a most aggressive peripheral T cell lymphoma. Currently, there is no satisfactory treatment available for this neoplasm. We report the case of a woman with prominent skin and bone marrow involvement without detectable lymph node localization. This unusual presentation of disease responded well to polychemotherapy combined with autologous bone marrow transplantation.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1993

Different mechanisms of extracellular matrix remodeling by fibroblasts in response to human mammary neoplastic cells.

Human breast tumors are often associated with a fibrotic reaction termed desmoplasia. Tumor cells may indirectly modulate the composition of the extracellular matrix by influencing fibroblast properties. They may also directly interact with collagen fibrils leading to retraction of the matrix. We have studied in vitro the influence of various human mammary tumor cells on the proliferation rate of normal human fibroblasts and on their level of collagen synthesis, as well as their release of collagenase activity. Interactions between neoplastic cells and collagen matrix were investigated by incorporation of tumor cells in collagen gels (lattices) and measurement of their retraction. All cells tested (HBL100, SW613, SA52, MDA-MB-231, MCF7, MCF7/6, MCF7 ras, BT20 and T47D) were able to modulate the composition of the extracellular matrix by one or several of the mechanisms investigated. Our results also demonstrate an opposite regulation of collagen and collagenase production. The effects on the collagen metabolism and on fibroblast proliferation are probably mediated by soluble cytokines since they are reproduced by incubating the fibroblasts in the presence of medium conditioned by tumor cells. The desmoplastic reaction may thus result from different mechanisms dependent upon tumor cell types.

Breast Neoplasms↗
PubMed1992

Effect of cell-cell and cell-matrix interactions on the response of fibroblasts to epidermal growth factor in vitro. Expression of collagen type I, collagenase, stromelysin and tissue inhibitor of metalloproteinases.

Investigations of the effect of epidermal growth factor (EGF) on the expression of four genes involved in the turnover of the extracellular matrix, collagen type I, collagenase, stromelysin and tissue inhibitor of metalloproteinases (TIMP) were performed on four strains of skin fibroblasts in vitro. Addition of EGF to subconfluent cultures for increasing periods of time up to 5 days induced an inhibition of procollagen alpha 1(I) mRNA and a strong stimulation of collagenase (100-fold) and stromelysin (1000-fold) mRNAs, whereas the mRNA of TIMP was increased to a lesser extent (5-fold). After a 40 h pulse with EGF, these effects persisted for 24-48 h after withdrawal of the growth factor and slowly diminished thereafter to attain control values after several days. By culturing fibroblasts for increasing periods of time, different levels of confluence were obtained allowing for the deposition of an extracellular biomatrix. The steady-state level of collagenase and stromelysin mRNAs were profoundly depressed in confluent as against non-confluent cultures, whereas no major change for TIMP and procollagen alpha 1(I) mRNAs was observed. Upon treatment of these cultures with EGF for 48h, the steady-state level of collagenase, stromelysin and TIMP increased, whereas procollagen alpha 1(I) mRNA was slightly reduced. These modifications were, at least in part, dependent upon a regulation of the transcription rate, as suggested from run-off experiments. Similar states of confluence were obtained by seeding cells at increasing densities in short-term cultures in which cell-cell contact predominated. In such culture conditions, the collagenase and stromelysin mRNAs were enhanced in high as compared to low density cultures. The response to EGF was progressively decreased for collagenase, stromelysin and, to a lesser extent, TIMP mRNAs at most densities and a complete lack of response to EGF at the highest cell density was observed. Under all culture conditions the modulation of collagenase mRNA was paralleled by similar modifications of enzyme activity. These results emphasize the importance of the cell-cell contacts and cell-matrix interactions in the expression of the genes coding for metalloproteinases or their inhibitor and their modulation by growth factors.

Cell Communication↗