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A Breton

Publications and source records attributed to A Breton.

23 records · Page 2Linked to original sources
PubMed1980

[Perforating generalized granuloma annulare. A two case study (author's transl)].

This article deals with two new cases of perforating generalized granuloma annulare characterized, from a clinical and biological standpoint, by a long course of evolution for one case and the presence of diabetes and dyslipidemia for the other case. Histologic study confirms the possible coexistence of typical granuloma annulare lesions with epidermic corbelar aspects pinching necrotic material which could lead to complete epidermic perforation. Based on the study of previous cases in the literature, the process of transepidermic elimination and the actual pathophysiologic concepts of granuloma annulare are reviewed. From the therapeutic standpoint, if the first case did not appear to profit from the administration of an alkylating agent, the second case seems to be presently improved through gluco-lipid re-equilibrium associated with lipocaic heparin.

Aged↗
PubMed1978

[Piebaldism. Clinical, pathological and ultrastructural study of three cases (author's transl)].

Comparative study of achromic and normally pigmented skin of three piebald patients from two families is reported here. DOPA-positive cells were not seen in the achromic areas, but the number of ATPase sites appeared to be normal; therefore the assumption of the replacement of the melanocytes by Langerhans cells cannot be supported. Through electron microscope, Langerhans cells looked strictly normal. Melanosomes appeared reduced in size and some alterations were noticed in their shape and contents. Ultrastructurally, a more prominent change consisted in increased undefined clear cells in the achromic skin. These dendritic suprabasal cells were devoid of melanosomes or Langerhans granules and might represent undifferentiated melanocytes. These features were discussed according to previous literature.

Adenosine Triphosphate↗
PubMed1977

Sulfate uptake in Saccharomyces cerevisiae: biochemical and genetic study.

Sulfate uptake is the first step of the sulfate assimilation pathway, which has been shown in our laboratory to be part of the methionine biosynthetic pathway. Kinetic study of sulfate uptake has shown a biphasic curve in a Lineweaver-Burk plot. The analysis of this plot indicates that two enzymes participate in sulfate uptake. One (permease I) has a high affinity for the substrate (K(m) = 0.005 mM); the other (permease II) shows a much lower affinity for sulfate (K(m) = 0.35 mM). Regulation of the synthesis of both permeases is under the control of exogenous methionine or S-adenosylmethionine. It was shown, moreover, that synthesis of sulfate permeases is coordinated with the synthesis of the other methionine biosynthetic enzymes thus far studied in our laboratory. An additional specific regulation of sulfate permeases by inhibition of their activity by endogenous sulfate and adenosyl phosphosulfate (an intermediate metabolite in sulfate assimilation) has been shown. A mutant unable to concentrate sulfate has been selected. This strain carried mutations in two independent genes. These two mutations, separated in two different strains, lead to modified kinetics of sulfate uptake. The study of these strains leads us to postulate that there is an interaction in situ between the products of these two genes.

Chromates↗