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T Marchal

Publications and source records attributed to T Marchal.

24 records · Page 2Linked to original sources
PubMed1995

Immunophenotypic and ultrastructural evidence of the langerhans cell origin of the canine cutaneous histiocytoma.

Canine cutaneous histiocytoma (CCH), a histiocytic benign, dermal, self-healing tumor in the young dog, and epidermal Langerhans cells (LC) are thought to be related. In this study, we used immunohistochemical staining and transmission electron microscopy for 5 fresh CCH and 17 fixed tumors, to examine if, on the basis of their immunophenotype and their ultrastructural morphology, these tumor cells originate as LCs. The immunophenotype of CCH: canine CD11a, 11c, 18, 45, MHC II positive and ACM1, human CD14 negative, was different from canine macrophage immunophenotype but very similar to the canine LC phenotype. Furthermore, we have described ultrastructural markers in CCH cells for the first time: these consist of coated vesicles, regularly laminated bodies, pleiomorphic inclusions, paracrystalline structures, and deep invaginations of the plasma membrane, usually observed in congenital self-healing histiocytosis, a human LC tumor, or occasionally observed in human LC. The occurrence of such immunophenotype and ultrastructural markers confirmed the common lineage of LCs and CCH cells.

Animals↗
PubMed1995

[Malignant lymphoma with medium-sized macronucleolated cells in the dog: involvement of an original cell from the marginal zone of the reactive lymph node].

Among the non-Hodgkin's malignant lymphomas of the dog, which are largely dominated by the centroblastic heterogeneous type, there is an original form of malignant lymphoma which is homogeneous and diffuse, with macronucleolated medium-sized cells. These cells seem to be morphologically very similar to those which constitute the majority population in the marginal zone of the secondary follicle of the lymph node in the dog, and which appear in the course of certain conditions: systemic lupus erythematosus, leishmaniasis, satellite lymph nodes in benign or malignant tumors. The aim of this study was twofold: on the one hand to establish, in the canine species, the identity of the lymphomatous cells and the reactive cells that make up the marginal zone, i.e. the filiation between the hyperplastic marginal zones and the macronucleolated malignant lymphoma with medium-sized cells, and, on the other hand, to compare this type of malignant lymphoma with those which are reputed to originate in the marginal zone in humans, for example the malignant lymphoma of the lymphoid tissue associated with the mucous membranes, and the monocytoid malignant B-cell lymphomas. Ninety four malignant lymphomas were observed between 1989 and 1994 at the Veterinary School in Lyon; these consisted of 71 cases showing medium or high-grade malignancy, 17 cases with small cells, of low-grade malignancy, and 6 cases of mycosis fungoides. Among the 71 cases of medium and high-grade malignancy, 8 were immunoblastic, 5 centroblastic homogeneous, 50 centroblastic heterogeneous, and 8 homogeneous with macronucleolated medium-sized cells. The methods used in these 94 cases were of a morphological type: cytology, histology, transmission microscopy and immunohistochemistry. The cytohistological, ultrastructural and immuno-phenotypical characteristics (CD3-, CIg-, Ki-67- phenotype) of the lymphomatous cells and the cells of the marginal zone were found to be identical, in the dog; this strongly suggests B-lineage cells which do not secrete cytoplasmic immunoglobulins and are not involved in the cell cycle. Finally, these cells seem to us to be morphologically very similar to the minority population described by Van den Oord in the marginal zone of the secondary follicles in the lymph node in humans, in certain reactive situations.

Animals↗
PubMed1995

[Dendritic cells in dogs and cats: models of study in human pathology].

Langerhans' cells (LC) are epidermal bone-marrow-derived dendritic cells. They represent in mankind 1 to 6% of the epidermal cells from which they can be distinguished by specific phenotype (membrane receptors and antigens related to the immune function) and by ultrastructural specific organelles: the Birbeck granules. In dogs and cats, such cells were recently described; they display a phenotype very similar to that of human LC (CD1, CD8, CD11/18, CD45 and MHC II positive for canine LC, and CD18, CD4, panleukocyte antigen and MHC II positive for feline ones) and in both species, Birbeck granules are observed. Furthermore occurs in dog a benign self-healing LC tumor: the canine cutaneous histiocytoma (CCH). This tumor exhibits numerous comparison points with a human LC disorder named Hashimoto-Pritzker disease, and thus may constitute an interesting model to explore causes of such a proliferation and mechanisms of tumor rejection. In 1986, Pedersen isolated in cats a new retrovirus very similar to the human immunodeficiency virus (HIV), the feline immunodeficiency virus (FIV). Since human LC may be infected by HIV, feline LC may represent a good candidate for an FIV model for exploring the infection of human LC by the HIV and for shedding light on the role of human LC located in the mucous membranes in the initial viral inoculation process.

Animals↗
PubMed1994

Autoimmune haemolytic anaemia presenting 9 years prior to Castleman's disease.

Castleman's disease (CD) is a rare disease of unknown aetiology and pathogenesis. We present an unusual case of abdominal CD in whom the first manifestation was an autoimmune haemolytic anaemia presenting 9 years before the diagnosis. The Coombs test became negative 2 months after surgical resection of the mass, suggesting that the mass was the source of the autoantibody. CD may be present in autoimmune haemolytic anaemia in patients with no evidence of any other disease.

Adult↗
PubMedDate not supplied

Contribution of the feline Langerhans cell to the FIV model.

In order to identify an equivalent of Langerhans cells in cat stratified epithelia, we used a panel of monoclonal antibodies known to be reactive with membrane antigens present on human Langerhans cells. The labelling was carried out by immunoperoxidase staining, for examination by light microscope, and by immunogold labelling, for electron microscopy. Out of 18 antibodies tested, only one, MHM23 antibody, specific against CD18 antigen, presented reactivity with dendritic epithelial cells on either frozen sections, epidermal sheets or cell suspension cytospins. On the ultrastructural level, these clear, dendritic, CD18+ cells showed "zipper-like" shapes similar to Birbeck granules, which are characteristic ultrastructural markers of Langerhans cells. This observation favours the hypothesis that these CD18+ cells in cat stratified epithelia are the equivalent of human Langerhans cells. These labelled cells were found in all epidermal locations and in the mucous membranes (oral, vaginal, rectal and oesophageal membranes). As feline immunodeficiency virus (FIV) transmission may occur through these membranes, the involvement of these feline Langerhans cells was studied in cats seropositive for FIV.

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