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Biomedical subjects

Y Merot

Publications and source records attributed to Y Merot.

At least 19 recordsLinked to original sources
PubMed1991

Anetodermic prurigo nodularis (with Pautrier's neuroma) responsive to arotinoid acid.

A woman had symmetrically distributed pruritic nodules for more than 40 years. Microscopically they were characterized by proliferation of nonmyelinated nerve fibers (Pautrier's neuroma) and a total absence of epidermal involvement. Anetoderma developed at the site of former nodules. Her condition responded favorably to repeated retinoid therapy with regression of nodules in those sites in which retinoid dermatitis had developed.

Aged↗
PubMed1990

Nucleolar organizer regions in fibrohistiocytic tumors of the skin.

Nucleolar organizer regions (NORs) are loops of DNA which are present within the nucleoli of cells that possess ribosomal RNA (rRNA) genes. NORs are associated with proteins which can be visualized by a simple silver staining technique. As the number of NORs appears to reflect cell and nuclear activity its determination in benign, intermediate and malignant conditions could be of help in their differential diagnosis. In this study, we investigated 35 fibrohistiocytic tumors of the skin of benign, intermediate and malignant potential from 32 patients: 15 fibrous histiocytomas (FH), 5 FH with atypia (AFH), 7 atypical fibroxanthomas (AFX), 5 dermatofibrosarcoma protuberans (DFSP) and 3 malignant FH (MFH). A one-step silver technique was used on formalin or Bouin fixed specimens. Ag-NOR counts from benign conditions (FH, AFH) significantly differed from that of their intermediate-risk (AFX, DFSP) and malignant (MFH) counterparts. Furthermore, in 2 cases (one AFX; one MFH) which twice recurred, Ag-NOR counts steadily increased with time. However, a distinction could not be achieved between AFX and MFH. Although Ag-NOR is a simple and valuable technique, it does not allow a definite distinction between malignant and intermediate processes, at least as far as fibrohistiocytic tumors of the skin are concerned.

Diagnosis, Differential↗
PubMed1989

Merkel cell hyperplasia in hypertrophic varieties of actinic keratoses.

Hyperplasia and dysplasia of the epidermal neuroendocrine cells (i.e., Merkel cells, MC) have been suggested in lesional skin of actinic keratosis and chronic radiation dermatitis. Because several histological types of actinic keratosis exist, we investigated the occurrence of such MC hyperplasia according to each of the histological patterns. Using an immunoperoxidase technique and the cytokeratin monoclonal antibody CAM 5.2, we counted 0.02 CAM 5.2 + cells (i.e., MC)/mm epidermis in normal-appearing perilesional skin; 0.05 MC/mm epidermis in nonhypertrophic actinic keratoses and 4.09 MC/mm epidermis in hypertrophic actinic keratoses. This number was as high as 14.40 MC/mm epidermis when hypertrophic actinic keratoses showed club-like epithelial proliferations. In contrast to normal epidermis, where MC were found isolated within the basal cell layer, MC clustered in these club-like epithelial proliferations as they did in the normal parakeratotic zone of the rabbit lip epithelium. The significance of this selective MC hyperplasia is discussed.

Animals↗
PubMed1987

Systemic administration of etretin increases epidermal interleukin I in the rat.

We have studied the effect of systemic administration of etretin (Ro 10-1670) on the epidermal interleukin I (ILI) pool in the rat. Hairless rats were given varying doses of etretin intraperitoneally for 21 days, or a fixed dose for 2, 8 and 16 days. Abdominal skin was taken and processed for light microscopy, autoradiography (using [3H]-thymidine) and ILI assays. ILI was assayed in supernatants of epidermal extracts by both the lymphocyte activating factor (LAF) assay and the stimulation of prostaglandin E2 (PGE2) release from dermal fibroblasts. A significant increase in both LAF and PGE2 stimulatory activities was found during etretin administration. After 21 days' treatment with varying doses there was a two- to three-fold increase as compared to the controls, with a peak at 2 and 5 mg/kg. At a fixed dose a two-fold increase was found after 2 days and a three- to four-fold increase after 16 days; normal pretreatment values were restored 16 days after cessation of etretin. This is the first demonstration in vivo that a retinoid can modulate ILI content in a tissue. As epidermal ILI has been found to be decreased in psoriasis, its modulation by retinoids might have therapeutic significance.

Acitretin↗
PubMed1987

Immunotactoid glomerulopathy with leucocytoclastic skin vasculitis and hypocomplementemia: a case report.

Immunotactoid glomerulopathy is a recently described entity characterized clinically by proteinuria, hematuria and hypertension, and on renal biopsy by various glomerular lesions including extracellular microtubules composed of immune reactants. Furthermore a defined immunological disease or cryoglobulinemia are absent. We report the case of a patient with immunotactoid glomerulopathy and hypocomplementemia (low C3 level) who developed several episodes of leucocytoclastic skin vasculitis with large immune deposits in and around small vessels. It is suggested that skin and renal involvement are part of the same systemic disease.

Antigen-Antibody Reactions↗
PubMed1987

Recurrent and metastatic cutaneous neuroendocrine (Merkel cell) carcinoma mimicking angiosarcoma.

An elderly man presented with bright red-to-purple confluent nodules and plaques of the scalp that appeared clinically consistent with angiosarcoma. He had undergone surgical removal of a similar lesion from his left temple seven months before this presentation. Although routine histologic examination was not sufficient for diagnosis, Merkel cell carcinoma was diagnosed by immunohistochemical studies and electron microscopy. In addition, oat cell carcinoma of the lung was excluded with a computed tomographic scan of his chest. With chemotherapy, the recurrent and metastatic lesions of Merkel cell carcinoma completely resolved, rapidly recurred, and resolved a second time with chemotherapy. Eight months following the fourth course of chemotherapy, the patient again developed widespread cutaneous lesions. He committed suicide within one month of this last recurrence. An autopsy revealed no primary tumor other than of the skin.

Aged↗
PubMed1986

The spectrum of minimal deviation melanoma: a clinicopathologic study of 21 cases.

A retrospective study of 21 patients with the histopathologic diagnosis of minimal deviation melanoma (MDM; n = 18) and borderline melanoma (BM; n = 3) was undertaken to determine the prognosis for these patients compared with that for patients with other types of malignant melanoma. The findings indicate that the prognosis for these uncommon nevomelanocytic tumors is somewhat better than that for other malignant melanomas. Follow-up periods in this series ranged from 18 to 96 months (mean, 57 months). Primary lesions ranged in thickness from 1.6 to 10.4 mm. The histopathologic subtypes included the Spitz variant (nine patients), the spindle cell variant (six patients), the combined spindle and epithelioid cell type (three patients), and the small epithelioid cell type (three patients). Only two of the patients died of widespread metastatic disease. Comparison of the histologic and clinical prognostic indicators of mortality in patients who have malignant melanoma with the clinical and pathologic features seen in this series of 21 patients would appear to indicate a diminished tendency toward metastatic or recurrent disease in patients with MDM and BM.

Adolescent↗
PubMed1986

Cellular retinoic acid- but not cellular retinol-binding protein is elevated in psoriatic plaques.

Cellular retinoid binding proteins are thought to be involved in the molecular action of retinoids, a family of compounds successfully used in the treatment of psoriasis. Therefore, both cellular retinol (CRBP)- and retinoic acid (CRABP)-binding proteins were analyzed in psoriatic skin. Three facts emerged from our study: both CRABP and CRBP are detectable in the skin of psoriatic patients; qualitatively, they both appear similar to the corresponding proteins of normal human skin, in terms of their elution profile and apparent Kd; and quantitatively, only CRABP was found to be 3 times higher in psoriatic plaques as compared to either nonlesional skin of psoriatic patients or the skin of normal subjects. Since psoriatic plaques are particularly responsive to systemic retinoids, specifically to retinoic acid analogues, our results suggest for the first time a link between the levels of CRABP and the responsiveness of a nonneoplastic hyperproliferative tissue to systemic administration of retinoids in the human.

Adult↗
PubMed1986

Coexpression of neurofilament and keratin proteins in cutaneous neuroendocrine carcinoma cells.

Four cases of neuroendocrine carcinomas (NECA) of the skin were studied by indirect immunofluorescence, using a monoclonal antikeratin antibody and a polyclonal antineurofilament antibody. Fifty to ninety percent and 80 to greater than 95% of the NECA cells stained with the antineurofilament antibody and the antikeratin antibody, respectively. Using double-labeling indirect immunofluorescence we could also demonstrate that, in 3 cases studied, some of the NECA cells, but not all, stained with both antikeratin and antineurofilament antibodies. These results, together with the recent knowledge of the intermediate filament protein type of normal Merkel cells (MC), tend to support the hypothesis that NECA cells do not originate from epithelial MC but from dermal neuroendocrine cells. A dual concept of intraepithelial MC and extraepithelial intradermal neuroendocrine cells, "from possible distinct origin," is proposed. Such a system has already been suggested for the neuroendocrine cells of the appendix and bronchial mucosae.

Adenocarcinoma↗
PubMed1986

Lymphocyte subsets and Langerhans' cells in toxic epidermal necrolysis. Report of a case.

Toxic epidermal necrolysis is a life-threatening disease, the pathogenesis of which remains largely unknown. Histologically, in addition to the characteristic epidermal alterations, there is a sparse mononuclear cell infiltrate in the dermis. The immunologic characteristics of this infiltrate are not well known. In a case of drug-induced toxic epidermal necrolysis with fatal outcome in a 48-year-old man, we demonstrated that the majority of the inflammatory cells were of helper/inducer T-lymphocyte subsets, having only a minority of cytotoxic/suppressor T-lymphocytes and rare cells with natural killer cell phenotype. The significance of these observations is discussed, with reference to the occurrence of lesions at epithelial sites bearing local networks of antigen-presenting cells (Langerhans' cells).

Animals↗