[Mucocutaneous hyalinosis: clinical polymorphism].
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Biomedical subjects
Publications and source records attributed to M Benveniste.
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Interactions between membrane proteins are believed to be important for the induction of transmembrane signaling. Endocytosis is one of the responses which is regulated by both intracellular and extracellular signals. To study such interactions, we have measured the lateral mobility and rate of endocytosis of epidermal growth factor receptor in three transfected NIH-3T3 cell lines (HER84, HER22, and HER82) expressing 2 X 10(4), 2 X 10(5) and 1.5 X 10(6) EGF-receptors per cell, respectively. Using rhodamine-labeled EGF (Rh-EGF) and rhodamine-labeled monoclonal anti-EGF-receptor antibody (Rh-mAb-108), we measured twofold decreases in the lateral diffusion coefficients for each approximately 10-fold increase in EGF-receptor concentration. Since steric effects cannot account for such dependence, we propose that protein mobility within the membrane, which is determined by the rate of motion between immobile barriers, decreases due to aggregate formation. The rate of endocytosis also decreases twofold between the HER84 (2 X 10(4) receptors/cell) and HER22 (2 X 10(5) receptors/cell) cell lines, suggesting that it is diffusion limited. The comparable rates of endocytosis of the HER82 and HER22 cell lines suggest that at high receptor density endocytosis may be limited by the total number of sites for receptors in coated-pits and by their rate of recycling.
The lateral diffusion coefficients of various epidermal growth factor (EGF) receptor mutants with increasing deletions in their carboxy-terminal cytoplasmic domain were compared. A full size cDNA construct of human EGF receptor and different deletion constructs were expressed in monkey COS cells. The EGF receptor mutants expressed on the cell surface of the COS cells were labeled with rhodamine-EGF, and the lateral diffusion coefficients of the labeled receptors were determined by the fluorescence photo-bleaching recovery method. The lateral mobilities of three deletion mutants, including a mutant that has only nine amino acids in the cytoplasmic domain, are all similar (D approximately equal to 1.5 X 10(-10) cm2/s) to the lateral mobility of the "wild-type" receptor, which possess 542 cytoplasmic domain of EGF receptor, including its intrinsic protein kinase activity and phosphorylation state, are not required for the restriction of its lateral mobility.
The association of Kaposi angiosarcomatosis and an auto-immune haemolytic anaemia is reported in a 69-year-old woman. The direct Coombs test was "igG complement" type positive. This is the 5th reported case and the 2nd in which haemolysis developed during an acute malignant exacerbation of the disease. The patient died less than 4 months following the diagnosis of Kaposi's sarcoma, after treatment with prednisone and chlorambucil. Lymphoid and immunological abnormalities are not rare during the course of Kaposi's sarcoma. The reasons are discussed briefly.
The case of a 66 years old woman having presented an unusual cyclic dermatosis of 11 months duration is reported. The cutaneous elements were successively located in a subcutaneous, dermal and epidermal situation, and presented a spontaneous healing with sometimes deep retractive residual scars after an ulceration or not. Pathologically, the lesions consisted in dense mononuclear infiltrates and vascular lesions. This disease was associated with an immuno-deficiency state characterized by extremely low levels of circulating IgM. This deficit was found to be persistant as it was still present two years later. However during this lapse of observation no cutaneous lesions recurred. The possible connexions of such a case with those of lymphomatous granulomatosis are discussed. In the absence of pulmonary lesion in the case reported here, no identification to the syndrome isolated by Liebow seems permitted. The authors offer a new denomination for this unusual entity.
The authors present 5 cases of pemphigus induced by D-penicillamine in a series of 180 cases of rheumatoid arthritis treated with this medication. In addition, anti-epidermal intercellular substance antibodies were sought in 40 asymptomatic patients. No antibodies were found in this group. The notion of induced pemphigus seems well established, as is the value of testing for antibodies in the surveillance of D-penicillamine treatment.
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Rare cases of migrant circinated eruptions occurring during the course of lupus erythematosus have been published so far. They have been classified in two categories: 1) supposed toxicodermias due to antimalarials; 2) real cases of erythema annulare centrifugum, mostly inaugurating the L. E. In an exceptional case, a migrating eruption looking like an erythema annulare with a complicated pattern on the trunk, neck and limbs, took place between two rashes of typical L.E. The exact nature of this eruption, clinically and histologically atypical, and its relation with the L.E. itself, have been discussed.
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