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S Peyrol

Publications and source records attributed to S Peyrol.

At least 55 records · Page 3Linked to original sources
PubMed1992

Characterization of the smooth muscle cell infiltrate and associated connective matrix of lymphangiomyomatosis. Immunohistochemical and ultrastructural study of two cases.

Lymphangiomyomatosis (LAM) consists of smooth muscle (SM) cell proliferation of unknown origin involving the lymph nodes and the lung interstitium. From morphological studies showing both SM differentiation of the proliferating cells and lymphatic hyperplasia, hypotheses were suggested concerning the origin of the proliferation. Two cases of LAM were investigated by electron microscopy and immunohistochemistry; tissues were obtained by lymph node and open lung biopsies. Cytoplasmic and matrix protein markers were used in order to clarify the pattern of differentiation of the proliferating cells and to characterize their connective tissue environment. The proliferating cells present ultrastructural characteristics of SM cells; they contain vimentin, desmin, and alpha-SM actin and are devoid of Factor VIII, favouring a parieto-arterial origin. The connective tissue matrix inside the infiltrate is composed of interstitial collagens and basement membrane components. At the late stage of the disease, remodelling of the interstitial matrix accompanies the infiltrate and remains perilesional.

Adult↗
PubMed1992

Cell-matrix patterns in the cutaneous lesion of chromomycosis.

Chromomycosis is a chronic fungal infection characterized by dermal fibrosis with persisting fungi in situ, generally leading to a verrucous skin lesion. The absence of good clinical results under specific treatment suggests irreversibility of the fibrotic lesion. Frozen and paraffin-embedded skin biopsies of eleven patients with chromomycosis due to Phialophora pedrosoi were studied by immunohistochemistry and electron microscopy. Distinct cell-matrix patterns were found in different tissue localizations: neutrophilic abscesses with oedema and necrotic keratinocytes in the epidermis; dense connective matrix around inflammatory infiltrates, mainly composed of macrophages and giant cells, and organized granuloma in the dermis. Active fibroblasts and mast cells were constantly observed. The inability of fibrotic tissue to be remodelled seems correlated to the nature and the organization of the matrix components but, the factors triggering the initial fibrogenic events remain to be characterized.

Adult↗
PubMed1992

Ultrastructural localization of the major components of the extracellular matrix in normal rat nerve.

In this study we determined the ultrastructural distribution of the various components of the extracellular matrix (laminin, fibronectin, Type I, III, and IV collagens) of the normal peripheral nerve in adult rat. The localization of these macromolecules was investigated in basement membranes as well as in different areas of epi-, peri-, and endoneurium, by use of a pre-embedding immunoperoxidase method.

Animals↗
PubMed1992

The various domains of v-myb and v-ets oncogenes of E26 retrovirus contribute differently, but cooperatively, in transformation of hematopoietic lineages.

The genome of the avian leukemia virus E26 is a unique example of association between two transcription factors which appear as a fused composite nuclear oncoprotein, P135gag-myb-ets. Previous studies with E26 have shown that v-myb and v-ets must cooperate to fully transform both erythrocytic and myelomonocytic precursor cells in vivo and in vitro. To analyse further the contribution of the individual domains involved in the transformation of various hematopoietic lineages, we have constructed several mutant viruses expressing a fusion protein with deletions in either v-myb or v-ets. We show here that integrity of the v-ets oncogene is necessary for transformation of the erythrocytic cells but that neither the DNA-binding domain nor the trans-activating domain of v-myb is required for this transformation. The DNA-binding domain of v-ets is necessary to transform myelomonocytic cells. Furthermore, we show that E26 onco-protein also transforms granulocytic cells. The v-ets DNA-binding domain is not necessary to transform them, whereas deleting the v-myb DNA-binding domain strongly reduces transformation of these cells. These data show that the v-myb and v-ets DNA-binding domains provide quite different contributions to the transformation of various hematopoietic lineages by E26.

Animals↗
PubMed1991

EGF-R as a hemopoietic growth factor receptor: the c-erbB product is present in chicken erythrocytic progenitors and controls their self-renewal.

c-erbB, encoding the EGF receptor (EGF-R), was originally identified as the cellular homolog of a chicken leukemia oncogene. In humans, EGF-R is distributed widely except in hemopoietic tissues, and its amplification is associated with epidermal and glial malignancies. Here we show that c-erbB is present in normal chicken erythrocytic progenitors and transmits the mitogenic signal induced by TGF alpha. Cells that contain high affinity EGF-R are at approximately the BFU-E stage, and their long-term renewal can be induced by TGF alpha. Upon addition of insulin and erythropoietin, they can be induced to terminally differentiate into red cells. We previously demonstrated that v-erbA blocks differentiation of chicken erythrocytic progenitors but does not abrogate their growth factor dependence for proliferation. These data indicate that proliferation and differentiation are not necessarily coupled in these cells. They also demonstrate a direct role of c-erbB in the control of self-renewal of normal chicken erythrocytic progenitors and could account for the predominant leukemogenic potential of the chicken erbB gene.

Animals↗
PubMed1991

Desmin expression in fibroblasts of murine periovular granuloma during liver Schistosoma mansoni infection.

We have studied the expression of the desmin gene, a muscle-specific intermediate filament protein in the granuloma cells of mouse liver infected with Schistosoma mansoni. In situ hybridization using a desmin DNA probe showed that fibroblastic cells in the granuloma strongly expressed desmin mRNAs, while in normal liver these cells did not express this mRNA to a detectable degree. The quantitative analysis of total RNAs demonstrated that the proportion of specific desmin mRNA increased from 14 to 18 weeks after infection and decreased at 20 weeks. The analysis of collagen gene expression indicated that the amount of type III collagen mRNAs was still increasing after 18 weeks from infection; in contrast, the amount of type I collagen mRNAs remained unchanged at that stage. A good correlation was observed between the detection of the specific mRNAs and the detection of both desmin and collagen molecules. Therefore, these data point to a coordinate induction of desmin and collagen gene expression during Schistosomal granuloma formation. They also suggest that the expression of the myofibroblast phenotype involves the induction of both genes.

Animals↗
PubMed1991

Tissue hyperfibrils are degraded forms of collagen fibrils. An ultrastructural study employing enzymatic treatments.

To elucidate the origin of collagen hyperfibrils, we have ultrastructurally investigated the development of collagen fibrils after in situ treatment of liver tissue sections by different proteolytic enzymes. After treatment, collagen fibrils were largely disorganized within the same fibril bundle. A wide range in diameters was observed. Hyperfibrils, which correspond to those fibrils with the largest diameters and having a flower-like section, were present. On the basis of these results, we can suggest that hyperfibrils reflect breakdown states of collagen fibrils.

Actin Cytoskeleton↗
PubMed1991

[Coral and guided tissue regeneration. Histological aspects].

During the past ten years, biotechnical and scientific advancements in periodontics have improved our knowledge concerning healing (with the concept of guided tissue regeneration) and bone filling (with the new available materials). A combined therapy using both Gore-Tex membranes and Biocoral 450 seemed well indicated for the treatment of an advanced adult periodontitis case. Histological observation of healing tissue biopsy has provided interesting findings concerning coral and cell behavior during the early stages of healing. Besides the slow resorption of the coral, early intrafibrillar calcification processes seem to occur, thus enhancing the regenerative potential.

Alveolar Bone Loss↗
PubMed1991

Characterization of fat-storing cell lines derived from normal and CCl4-cirrhotic livers. Differences in the production of interleukin-6.

Liver fat-storing cells (FSC) play an important role in collagen deposition. During the induction of liver cirrhosis, FSC lose their fat droplets, acquire an actin-rich cytoskeleton and transform into myofibroblasts. Myofibroblasts have been associated with increased collagen production in cirrhotic livers. Cultured FSC resemble myofibroblasts. However, it is not known whether regulation of collagen gene expression is similar in FSC obtained from normal or cirrhotic livers. In this communication, we describe the characterization of two fat-storing cell lines, one from normal (NFSC) and one from CCl4-cirrhotic liver (CFSC), obtained after spontaneous immortalization in culture. We studied the effect of serum and various growth factors on cell proliferation. We determined the production of collagen and fibronectin and we analyzed the presence of mRNA transcripts of collagens type I, III, and IV, fibronectin laminin, transforming growth factor-beta and interleukin-6. We found that CFSC have a greater serum-dependency than NFSC. NFSC grow with a mixture of insulin and epidermal growth factor, whereas CFSC proliferate only with platelet-derived growth factor. Although we did not find significant differences in the expression of mRNAs for collagen type I, fibronectin and transforming growth factor-beta, collagen and fibronectin synthesis was increased 2- and 1.5-fold respectively. NFSC contained 1.6- and 2.0-fold more type III collagen and laminin mRNAs, respectively, than CFSC. Neither cell line expressed type IV collagen mRNA. NFSC but not CFSC produced interleukin-6. These results suggest that, except for the lack of transcripts of collagen type IV, both cell lines resemble primary cultures of FSC. However, significant differences in cell proliferation and interleukin-6 production between the two cell lines were found. We suggest that these cell lines could be useful tools to study possible differences in regulation of matrix production by FSC.

Adipose Tissue↗
PubMed1991

[Bronchiolitis obliterans organizing pneumonia (BOOP). Characteristics and boundaries of an anatomo-clinical entity].

Bronchiolitis obliterans organizing pneumonia (BOOP) is defined by endoluminal obstruction of distal airspaces by a fibrous granulation tissue consisting of inflammatory cells, fibroblasts, and connective tissue. The morphogenesis of the process is the following: diffuse alveolar injury leading to basement membrane denudation and intra-alveolar exudate of fibrinogen, immunoglobulins, coagulation factors, fibronectin; intra-alveolar migration of interstitial fibroblasts through gaps of the epithelial basement membrane; intra-alveolar secretion of loose connective tissue (codistribution of collagens I, III, V, and fibronectin) by the fibroblasts-myofibroblasts. The main characteristic of this peculiar fibrosis is its possible reversibility. BOOP is not specific for any aetiology, and it is found in various conditions as infectious diseases, drug induced pulmonary diseases, connective tissue diseases. It is also present in other conditions where it is not the most contributive information to diagnosis (hypersensitivity pneumonitis, chronic eosinophilic pneumonia). But in some cases BOOP remains idiopathic and has to be individualized. Three clinical and imaging profiles are distinguished: the most characteristic consists of an inflammatory context with imaging patchy alveolar opacities, migrating and relapsing, and most steroid sensitive; the other two presentations are less remarkable: pseudo-neoplastic localized chronic pneumonia, and diffuse infiltrative lung disease. BOOP is a clinico-pathologic entity that the clinician must know because of the efficacy of corticosteroid treatment in most cases, and it further represents an unique model to understand the pathogenesis of fibrosing pulmonary diseases.

Bronchiolitis Obliterans↗
PubMed1991

Experimental chemotherapy of Trypanosoma cruzi infection: persistence of parasite antigens and positive serology in parasitologically cured mice.

Mice infected with Trypanosoma cruzi, but parasitologically cured after specific chemotherapy, continued to exhibit positive indirect immunofluorescence serological tests 3-6 months after the therapy. Treatment of trypanosome antigens with monospecific antisera produced in rabbits, and examination by immunoelectron-microscopy following peroxidase labelling disclosed the presence of membrane deposits in cell processes in the spleens of the mice. Similar deposits were observed in the external membranes of T. cruzi amastigotes in the spleens of acutely infected mice, but not in normal control mice. No reaction occurred in tissues not previously treated with the monospecific anti-T. cruzi serum. Positive cells in treated and cured mice, as well as in the not cured or untreated control mice, were located in germinal centres of the splenic white pulp and presented long and branching cytoplasmic processes, which are indicative of dendritic cells of the lymphoid follicles of the spleen.

Animals↗
PubMed1991

[Three-dimensional model of cancer and in vitro metastasis: application to non-Hodgkin malignant lymphoma].

In vitro cancer studies require models more appropriate than the standard monolayer cultures of tumoral cell lines. This report describes the production of an in vitro three-dimensional rebuilt tumor using a non-hodgkin malignant lymphoma. The model exploits the relationship between angiogenesis and cancer formation by employing both tumor cells and fusiform cells derived from an angioma. The significance of this model, which has also been used with malignant melanoma cells, is that the rebuilt tumor, when placed in culture, produces many tumorous nodules which are fixed to a sub-layer of fusiform cells and newly-secreted matrix. These are, in effect, in vitro metastases. The ultrastructural aspect of this neomatrix indicates its proteoglycan nature. The micro-environment formed by the vascular cells and matrix appears to be critical for the production of metastases.

Cell Line, Transformed↗
PubMed1990

Elastin in human, baboon, and mouse liver: an immunohistochemical and immunoelectron microscopic study.

Light microscope histochemistry and immunohistochemistry, and routine electron microscopy techniques were performed to analyse elastin distribution and structure in the human liver compared with that in baboon and mouse. In man and baboon, elastic fibers stained by iron hematoxylin or orcinolnew fuchsin seemed to be solitary and were few in number; in the mouse they were thinner but abundant, both in the portal tract and in hepatic veins. Orcein or resorcin-fuchsin stains, employed after oxidation of tissue sections, revealed a network comprising elastic, elaunin, and oxytalan fibers, which was also demonstrated by immunofluorescence with anti-elastin antibody in man and baboon. At the ultrastructural level, the elastic fibers of the human portal tract corresponded to discontinuous patches of amorphous material intermingled with few microfibrils. These contrasted with the thinner elastic fibers of baboon and mouse liver which had a core of amorphous material. In man and baboon, these fibers meshed into slender bundles of microfibrils often exhibiting small spots of amorphous material (elaunin fibers) and terminated as isolated microfibrils (oxytalan fibers). Immunoelectron microscopy of elastin carried out on baboon liver tissue labelled the amorphous material and also its microfibrillar component. Immunoperoxidase deposits were also associated with isolated bundles of microfibrils in the baboon portal stroma. Immunolabelling and elastic stains disclosed an important elastin portal network located around vascular, biliary structures and interspaced with collagen bundles. The structural polymorphism of elastin, assembling different relative amounts of amorphous material and microfibrils, might have a relationship with the required elasticity in a given species.

Adult↗
PubMed1990

Intra-alveolar fibrosis of idiopathic bronchiolitis obliterans-organizing pneumonia. Cell-matrix patterns.

Idiopathic bronchiolitis obliterans-organizing pneumonia (BOOP) is characterized by air space fibrosis of unknown origin. Clinical resolution under steroid treatment suggests the removal of the fibrotic lesion. Open lung biopsies of four patients with idiopathic BOOP were studied by immunochemistry and electron microscopy. Three distinct cell-matrix patterns of intra-alveolar bud were found to represent the sequential evolution of the fibrotic process: fibrinoid inflammatory cell clusters in which immunoglobulins and procoagulant factors (fibrinogen, factors VII and X) were identified; fibroinflammatory buds in which desmin-containing fibroblasts were observed migrating, proliferating, and secreting matrix proteins; fibrotic buds in which myofibroblasts organized a loose connective matrix predominantly composed of fibronectin and type III collagen. Extending forms of fibrotic buds may join contiguous alveoli. Fibrotic bud remodeling ability is correlated to the nature and organization of the matrix components but the factors permitting intra-alveolar matrix degradation must be characterized.

Blood Coagulation Factors↗
PubMed1989

Immunohistochemical localization of type IV collagen fibronectin and laminin in the juxtaglomerular apparatus of the rat kidney.

The juxtaglomerular apparatus (JGA) is a complex structure containing several components: the vessels, the extraglomerular mesangium and the distal tubule. These structures include cellular elements and an extracellular matrix (ECM). Collagenous (type IV collagen) and noncollagenous components of the basement membranes were studied. The localization of type IV collagen and of two extracellular glycoproteins (laminin and fibronectin) was investigated using immunofluorescent and immunoperoxidase labelled antibodies. Type IV collagen and laminin have the same localization on the JGA basement membranes. On the other hand, fibronectin is limited to the entrance of the glomerular stalk. On electron microscopy, type IV collagen is found in the basement membrane while fibronectin is restricted to certain areas of the extracellular matrix. These findings confirm data concerning the distribution of these three components in basement membranes and allow a better understanding of the histoarchitecture of the juxtaglomerular apparatus.

Animals↗
PubMed1987

Interactions between fibroblasts and a reconstituted basement membrane matrix.

A gel-like reconstituted basement membrane matrix containing type IV collagen, laminin, entactin, nidogen, and heparan sulfate proteoglycan was used to examine the interactions between normal calf skin fibroblasts and basement membranes. Within 6 h after seeding, fibroblasts initiated a migration that resulted in the formation of a cellular network after 1 day of culture on top of the gel. Electron microscopy revealed that fibroblasts were able to remodel the basement membrane matrix by penetrating into the gel (from day 3), depositing fibronectin and collagen fibers, and retracting this extracellular matrix. Fibroblasts cultured on the Engelbreth-Holm-Swarm reconstituted basement membrane matrix displayed ultrastructural features characterized by a poor synthetic apparatus (rough endoplasmic reticulum and Golgi vesicles), a large cytoskeleton, and intracytoplasmic vesicles containing laminin. Thus the reconstituted basement membrane matrix is remodeled by skin fibroblasts, and reciprocally their ultrastructural morphologic features are affected by this matrix.

Animals↗
PubMed1986

Organization of the connective matrix of the sarcoid granuloma. Evolution and cell-matrix interactions.

The connective matrix of sarcoid granulomas is polymorphic. Immunolabeling techniques show that it is partly composed of fibronectin and collagen types I and III and is found at all stages of the granulomas' evolution. This suggests that the process known as hyalinization is not due to changes in the composition of the matrix but results from a gradual accumulation of connective tissue components. Fibronectin seems to play an essential role as mediator between different cell populations during the evolution of the granulomas.

Abdomen↗