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M Faure

Publications and source records attributed to M Faure.

At least 181 records · Page 10Linked to original sources
PubMed1987

Expression of class I-MHC antigens by cultured human epidermis and epidermal allografts.

In vitro grown class II-MHC antigen free epidermal sheets were used as epidermal allografts (EAG) across a major histocompatibility barrier in 20 non-immunosuppressed recipients suffering from leg ulcers. Class I antigens were expressed on cell membranes of basal cell layer only on the epidermal sheets. After grafting, patchy areas of membrane fluorescence were observed among cells from the suprabasal layers on the epidermis from skin biopsies taken between days 5 and 28. All cells of the basal and the suprabasal layers expressed class I antigens on biopsies taken after day 28, as on normal human epidermis. This work demonstrates that class I antigens are expressed by epidermal cells in cultures used for grafting. The absence of rejection cannot be explained by the absence of class I-MHC antigens in EAG.

Adult↗
PubMed1987

Progressive replacement of human cultured epithelial allografts by recipient cells as evidenced by HLA class I antigens expression.

Human keratinocytes may be grown in vitro into living epithelia devoid of Langerhans cells and MHC class II antigens. These epithelia have been shown to be usable as epidermal allografts in patients with dermal wounds, without any apparent sign of rejection in the 12-month follow-up study. To evidence a progressive replacement by recipient cells of the grafted keratinocytes, we employed anti-MHC class I antigen monoclonal antibodies directed against tissue specificities expressed by either donors or recipients. At 2 and 4 weeks after grafting, some small epithelial cell islets from the recipient phenotype were clearly identified among cells from a donor origin by indirect immunofluorescence. At 6 months, all keratinocytes present at the grafted areas were labelled by antibodies directed toward recipient specificities only. This replacement may be related to the fact that, when placed on such superficial dermal wounds, the allografts are likely colonized by epithelial cells proliferating from residual recipient dermal appendages.

Antibodies, Monoclonal↗
PubMed1987

Expression of blood group antigens by cultured human epidermal cells used as allografts.

The expression of blood-group antigens was studied on human epidermal cultures used as allografts in 13 non-immunosuppressed patients treated for leg ulcers. The study was carried out using monoclonal antibodies to A and B antigens by an indirect immunofluorescence technique. Blood-group antigens are weakly expressed on the suprabasal layers of the cultured epidermal sheets. After grafting, the donor's blood-group antigens were detected on a few cells of the suprabasal layers. Furthermore, scattered keratinocytes as well as acrosyringia were found to express the recipient's blood-group antigens.

Antigens↗
PubMed1987

[Paranoid reactions and culture].

Paranoid Reaction (or bouffée délirante) according to the french classification was the basic psychosis of primitive societies. It corresponds to a need of defense of restructuration or restitution according to a pattern of "misconduction" admitted by the cultural environment. Paranoid reaction, in this respect, offers some relative good pronostic as soon as the goal is reached even if the previous personality remains modified. Paranoid reaction may get closer to hysterical crepuscular states. Some symptoms may also evoke schizophrenias. Evolution toward a lasting psychosis may be considered only in case the process of deculturation/acculturation is already engaged in an irreversible way and the defensive mode presented in the new cultural system shows schizophrenic patterns. Quick transformations and strong cultural pressures, trough that primitive societies are going, might increase dramatically chronic evolution of paranoid reactions. A case has been related to illustrate those considerations.

Acculturation↗
PubMed1986

Effects of temperature, ouabain and diuretics on the cell sodium and potassium contents of isolated rat kidney tubules.

Cell Na+ and K+ contents were measured by flame photometry in single pieces of rat medullary thick ascending limb (MAL) and medullary collecting tubules (MCT) after an overnight incubation at various temperatures. Below 8 degrees C, MCT samples were no more able to sustain high-K+, low-Na+ cell concentrations, and sodium progressively replaced cell potassium as the temperature decreased. The loss of potassium and the accompanying accumulation of sodium by MCT cells occurred at lower or higher temperature when amiloride (20 mumol/l) or ouabain (1 mmol/l) was present respectively in the incubation medium compared to that observed on control non-treated MCT. In contrast, MAL samples maintained normal cation gradients across their membrane at all temperatures, including 0 degree C, even in the presence of ouabain. However, MAL cells lost nearly all their potassium which was replaced by sodium when they were incubated in K+-free solution. These Na+-loaded, K+-depleted MAL cells restored high-K+ and low-Na+ contents similar to those of control samples when they were further incubated for 1 h at 0 degree C in presence of 5 mmol/l external potassium. Even in the presence of 1 mmol/l ouabain and at 0 degree C, a restoration of almost normal cation gradients occurred provided that Na+-loaded MAL were incubated for 24 h after potassium addition to the external medium. The results are discussed in relation to the respective effects of low temperatures on the passive and active components of the cation balance in the cells of the two nephron segments.

Amiloride↗
PubMed1986

Effects of external potassium concentrations on the cell sodium and potassium contents of isolated rat kidney tubules.

The effects of 20 mumol/l amiloride, 10 mumol/l furosemide and 1 mmol/l ouabain on cell Na and K concentrations were investigated by flame microphotometry in isolated rat medullary collecting tubules and medullary thick ascending limbs (MCT and MAL) as a function of the external potassium concentration [Ke]. The results are expressed as Na and K concentrations per liter cell volume ([Nac] and [Kc], mmol/l) and relative sodium content, [Nac]/([Nac] + [Kc]). From the experimental curves, [Ke]1/2 is defined as the [Ke] value corresponding to half maximal exchange of K against Na in cells. When [Ke] was 5 mmol/l, the relative Na content was less than 15% in control and amiloride-treated MCT as well as in control and furosemide-treated MAL, and about 24% in ouabain-treated MCT and MAL. In MCT, relative cell Na content increased up to 90% or more when [Ke] was reduced from 2.5 to 0.25 mmol/l. [Ke]1/2 was 0.55, 0.45 and 1.25 mmol/l for control, amiloride-treated and ouabain-treated MCT respectively. In MAL, similar increases in relative Na content were observed when [Ke] was reduced from 0.5 to 0.05 mmol/l. [Ke]1/2 was 0.25, 0.10 and 1.75 mmol/l for control, furosemide-treated and ouabain-treated MAL respectively. When [Ke] was reduced from 5 to 1 mmol/l, [Nac] dropped from 16.4 to 8.4 mmol/l (P less than 0.01) in control MAL. When [Ke] was 5 mmol/l, [Nac] was lower in furosemide-treated MAL (7.8 mmol/l) than control MAL (P less than 0.01). At 1 mmol/l [Ke], [Nac] was similar in both groups. These results are discussed in terms of the balance between the active and passive components of Na and K fluxes across apical and basolateral cell membranes. They indicate that a K-dependent passive Na entry process exists in the membranes of MAL cells but not of MCT cells. This process was proportionally more inhibited than the active Na pump when [Ke] was reduced from 5 to 1 mmol/l. In addition, it was found sensitive to furosemide.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Loss of allogeneic T-cell activating ability and Langerhans cell markers in human epidermal cell cultures.

Human Langerhans cells are the only epidermal cells that express the T6 and HLA-DR antigens and are responsible for the in vitro allogeneic T-cell proliferative responses in the mixed skin cell lymphocyte reaction (MSLR). To investigate the presence of Langerhans cells in normal human epidermal cell cultures, epidermal cell suspensions obtained from normal human skin specimens and from the subsequent epidermal cell cultures were analyzed by indirect immunofluorescence for the presence of T6 and HLA-DR determinants. In parallel, MSLRs were conducted with suspensions of cultured epidermal cells as stimulatory cells. These studies present evidence that when human epidermal cells are grown in culture, they loose both the ability to stimulate the proliferation of allogeneic T lymphocytes in vitro and their expression of HLA-DR and T6 antigens. The T6 antigens were lost during the first 2 weeks of culture, while HLA-DR determinants were still expressed by a small number of cells and were progressively lost through duration of cultures. The loss of HLA-DR antigens closely paralleled the progressive inability of human epidermal cells in culture to stimulate allogenic T cells in MSLR.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1986

Long-term survival and immunological tolerance of human epidermal allografts produced in culture.

Human epidermal cells from a small skin specimen can be grown in culture into multilayered sheets suitable for the permanent coverage of large burn wounds when used as epidermal autografts. We report here on the long-term survival of such cultured epidermal sheets used as epidermal allografts (EAG) across a major histocompatibility barrier in three nonimmunosuppressed adult patients, suffering from large chronic grafted leg ulcers, where the EAG have been placed to cover the conventional split-thickness skin autograft donor site. The absence of rejection was based upon clinical, histological, and immunopathological observation of the allografted sites at various intervals after grafting of the EAG. The identity of the epidermal cells on the grafted area with cultured cells from allogeneic donor was then established after blood substance typing by indirect immunofluorescence. Furthermore, epidermal cells from cultured sheets, but not control human cells from freshly excised normal epidermis, failed to stimulate the recipient peripheral blood cells in the mixed epidermal cell lymphocyte culture reaction, a finding that is related to the complete absence of class-II-antigen-bearing cells in cultured epidermis. This absence of T cell stimulation was noted not only on the day of grafting but throughout the follow-up. Altogether, these findings show that Langerhans cell and other class-II-antigen-bearing cell-depleted cultured epidermal allografts, are tolerated in unrelated recipients. EAG may serve as a skin substitute in patients with large wounds or burns. Since EAG may be grown continuously, the coverage of burns may not then be limited by the availability of the donor site, or by the time necessary to produce epidermal tissue in cultures.

Adult↗
PubMed1986

Ultrastructure of multilayered cultures of human gingival epithelial cells: attachment to enamel surfaces in vitro.

Human gingival cells were collected using an enzymatic procedure and seeded on a feeder layer of irradiated mouse 3T3 fibroblasts. Epithelial cells generate stratified colonies ultimately forming an epithelium which was studied using electron microscopy. When this epithelium-like structure was dispased and transferred to enamel surfaces, the relationship between basal cells and enamel corresponded to half-desmosomes and a discontinuous extracellular matrix.

Adult↗
PubMed1985

Production of a lymphocyte differentiating factor (ELDIF) by cultured human epidermal cells.

T lymphocyte maturation activity of supernatants from cultured human epidermal cells was investigated using a biological rosette assay based upon Thy 1 induction on T cell precursors. Between days 5 and 18 of keratinocyte cultures, supernatants exhibited Thy 1-inductive properties. Optimal activity was found between days 10 and 14 of culture, which correspond to the beginning of epidermal cell stratification. This activity was independent of the presence of prostaglandin E. Absorption experiments using monoclonal and polyclonal antibodies showed that ELDIF was different from other recognized thymic hormones (thymulin, thymopoietin, thymosin alpha 1), produced by thymic epithelial cells and known to induce T cell markers.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1985

Immunogold technique applied to simultaneous identification of T6 and HLA-DR antigens on Langerhans cells by electron microscopy.

A double-labeling immunogold technique in electron microscopy and specific monoclonal antibodies to surface antigens of Langerhans cells (OKT6 and BL2) were applied to assess directly the coexpression of two cell surface antigens (T6 and HLA-DR antigens) in a heterogeneous epidermal cell suspension. Electron microscopic examination of double-labeled cells revealed that all Birbeck granule-containing Langerhans cells bound OKT6 and BL2. The preparation of markers with colloidal gold particles and the procedure for double labeling are described. Several problems related to the steric hindrance and current artifacts are illustrated by micrographs and also discussed.

Antibodies, Monoclonal↗
PubMed1985

Recent advances of ultrastructural immunocytochemistry of epidermal Langerhans cells.

Using electron microscopy, the immunological visualization of the membrane antigens of Langerhans cells (LC) can be performed by immunoperoxidase and immunogold techniques. The immunoperoxidase labelling permits the identification of only one antigen and the observation of qualitative variations of surface antigens. The immunogold method allows the identification of one antigen or simultaneously two or three surface antigens using gold particles of various sizes. This technique can be used to quantify the surface density of antigens on the cell membrane. The simultaneous identification of different surface antigens can be correlated with the ultrastructural characteristics of the cells. Using this technique we have recently demonstrated the existence of LC subsets in normal epidermis, and the presence of circulating T6-positive cells in normal subjects. In addition, a very low density of T4 antigenic sites on the LC membrane surface was observed. Several problems of a double-labelling immunogold technique related to steric hindrance and current artifacts are discussed.

Antigens, Differentiation, T-Lymphocyte↗