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Biomedical subjects

G Guillet

Publications and source records attributed to G Guillet.

At least 37 records · Page 2Linked to original sources
PubMed2003

Genetic and functional analyses of FH mutations in multiple cutaneous and uterine leiomyomatosis, hereditary leiomyomatosis and renal cancer, and fumarate hydratase deficiency.

Germline mutations of the fumarate hydratase (FH, fumarase) gene are found in the recessive FH deficiency syndrome and in dominantly inherited susceptibility to multiple cutaneous and uterine leiomyomatosis (MCUL). We have previously reported a number of germline FH mutations from MCUL patients. In this study, we report additional FH mutations in MCUL and FH deficiency patients. Mutations can readily be found in about 75% of MCUL cases and most cases of FH deficiency. Some of the more common FH mutations are probably derived from founding individuals. Protein-truncating FH mutations are functionally null alleles. Disease-associated missense FH changes map to highly conserved residues, mostly in or around the enzyme's active site or activation site; we predict that these mutations severely compromise enzyme function. The mutation spectra in FH deficiency and MCUL are similar, although in the latter mutations tend to occur earlier in the gene and, perhaps, are more likely to result in a truncated or absent protein. We have found that not all mutation-carrier parents of FH deficiency children have a strong predisposition to leiomyomata. We have confirmed that renal carcinoma is sometimes part of MCUL, as part of the variant hereditary leiomyomatosis and renal cancer (HLRCC) syndrome, and have shown that these cancers may have either type II papillary or collecting duct morphology. We have found no association between the type or site of FH mutation and any aspect of the MCUL phenotype. Biochemical assay for reduced FH functional activity in the germline of MCUL patients can indicate carriers of FH mutations with high sensitivity and specificity, and can detect reduced FH activity in some patients without detectable FH mutations. We conclude that MCUL is probably a genetically homogeneous tumour predisposition syndrome, primarily resulting from absent or severely reduced fumarase activity, with currently unknown functional consequences for the smooth muscle or kidney cell.

Amino Acid Metabolism, Inborn Errors↗
PubMed2003

[Treatment of familial erythermalgia with the association of lidocaine and mexiletine].

INTRODUCTION: Erythermalgia is a rare acrosyndrome characterized by reddening of the skin, local increase heat and pain. The disease is frequently resistant to treatment. Recently, Kuhnert et al. presented very favorable results using a combination of lidocaine and mexiletine. We used this treatment in 4 patients suffering from familial erythermalgia. OBSERVATIONS: In a family exhibiting severe familial erythermalgia involving 5 members over 3 generations, we treated 4 patients aged 41, 39, 19 and 15 years. In these patients, the erythermalgia known since early childhood, progressed in the form of multiple flares (6 to 7/day) during the day and at night, lasting several hours and often accompanied by headaches. The impact of the disease on their quality of life was major. Only cold-water baths provided temporary relief, obliging them to live with their "feet in cold water". After they had been informed of the modalities of treatment and in the absence of any contraindication, notably cardiologic, 200 mg (100 mg in the youngest patient) of lidocaine were infused in 4 hours in a single intravenous injection on the first day. Mixelitine was introduced on the second day at the dose of 600 mg in 3 oral intakes (200 mg in the youngest patient). The painful paroxistic symptomatology rapidly improved and the flares had disappeared on the 3dr day, thus permitting the progressive reduction in analgesics and major improvement in quality of life. This beneficial effect persisted with oral mexiletine alone, 2 years after the infusion of lidocaine in the first patient treated (and one year after in the other patients). COMMENTS: Primary familial erythermalgia is highly resistant to treatment. The combined action of lidocain and mexiletine, usually well tolerated (class IB antiarrythmic), blocks the sodium channels. The mechanism of action of their analgesic effect is peripheral or central or even mixed. This benefit warrants confirmation in other forms of erythermalgia.

Administration, Oral↗
PubMed2001

The primary erythermalgia-susceptibility gene is located on chromosome 2q31-32.

Primary erythermalgia is a rare disorder characterized by recurrent attacks of red, warm, and painful hands and/or feet. The symptoms are generally refractory to treatment and persist throughout life. Five kindreds with multiple cases of primary erythermalgia were identified, and the largest was subjected to a genomewide search. We detected strong evidence for linkage of the primary erythermalgia locus to markers from chromosome 2q. The highest LOD score (Z) was obtained with D2S2330 (Z(max) = 6.51). Analysis of recombination events identified D2S2370 and D2S1776 as flanking markers, on chromosome 2q31-32. This defines a critical interval of 7.94 cM that harbors the primary erythermalgia gene. Affected members within the additional families also shared a common haplotype on chromosome 2q31-32, supporting our linkage results. Identification of the primary erythermalgia gene will allow a better clinical classification of this pleomorphic group of disorders.

Child↗
PubMed2001

[Photoallergic reactions to olaquindox in swine raisers: role of growth promotors used in feed].

BACKGROUND: The diagnosis of photodermatosis is generally facilitated by the typical localization of the eruption. The causal agent can usually be identified by history taking, allowing eviction and cure. It may be difficult to find the causal agent in cases with a sequential course. The occupational and/or recreational environment may provide helpful information. We present two cases of photodermatosis related to the occupational environment. CASE REPORTS: A 50-year-old woman and a 29-year-old man were farm workers. both consulted for photoinduced eczema. The eczema was triggered by episodic manipulation of an antibiotic used widely for preparing animal feed. The standard allergy tests were negative. The photobiology exploration led to the diagnosis of photoallergy to olaquindox, a growth promotor added to animal feed. The course was favorable after eviction or protection against the product, providing a complementary proof of its triggering effect. DISCUSSION: We emphasize the contribution of photobiological explorations in difficult cases with an occupational background. Generally, these patients are unaware of the composition of the products manipulated, such as feed additives.

Adult↗
PubMed2001

[Anti-endothelial cell antibodies in chronic leg ulcer: prevalence and significance].

BACKGROUND: Anti-endothelial cell antibodies are detected in auto-immune vasculitis and connective tissue diseases such as scleroderma, with possible pathogenic involvement. We looked for these antibodies in patients presenting chronic ulcers. PATIENTS AND METHODS: Eighty patients were tested: 35 presented vascular ulcers (27 of venous origin and 8 arterial). A control group of 14 patients with connective tissue disease and vasculitis was formed, and a third group included 31 patients without vascular or immune disease. Their sera were tested by ELISA technique on EAhy 926 cell (obtained from hybridization of human endothelial and line A 549/8 cells). RESULTS: Blood tests were positive in 37.5 p. 100 of patients. Antibodies were present in 48.5 p. 100 of patients with leg ulcers (of which 59 p. 100 (16/27) venous ulcers). Fifty-seven per cent of the autoimmune group and 12 p. 100 of the third group were positive. Association with anti-phospholipid antibodies was observed twice in leg ulcers. The level of antibodies was higher in patients with leg ulcers. COMMENTS: The presence of high levels of anti-endothelial cells antibodies in 48.5 p. 100 of patients presenting leg ulcers shows that these antibodies are not specific to autoimmune diseases. Since they are involved in coagulation, inflammation (enhancing of adhesion molecules and tissue lysis) and apoptosis of endothelial cells, their significance in chronic ulcers, both as a consequence and/or possible cofactor merits discussion.

Adolescent↗
PubMed2001

[Panniculitis and macrophage activation syndrome in a child with lupus erythematosus].

INTRODUCTION: Panniculitis is rarely presented in the course of systemic lupus erythematosus. When it occurs, it is mainly related to lupus profundus. However, when panniculitis is associated with a reactive hemophagocytic syndrome, panniculitis could be linked to this hemophagocytosis reaction. CASE REPORT: We report a case of an 11-year-old girl treated for several years for systemic lupus erythematosus, who simultaneously presented panniculitis and an hemophagocytic syndrome. The reality of both diagnoses was based on the analysis of biological and histological data. Therapy with immunosuppressive drugs led to relief of the symptoms. DISCUSSION: We emphasize our discussion on the pathophysiology of lupus profundus and hemophagocytosis with regards to the role of cytokines and circulating immune complexes in both diseases. They may enhance the hypodermal necrosis observed in lupus profundus and induce macrophage cell dysregulation through cytotoxic cells known in hemophagocytosis. The immunomodulative action of immunosuppressive therapy with inhibition of cells involved in immune response, may explain its efficacy.

Antigen-Antibody Complex↗
PubMed2000

Expression of tryptophan decarboxylase and tyrosine decarboxylase genes in tobacco results in altered biochemical and physiological phenotypes.

The substrate specificity of tryptophan (Trp) decarboxylase (TDC) for Trp and tyrosine (Tyr) decarboxylase (TYDC) for Tyr was used to modify the in vivo pools of these amino acids in transgenic tobacco. Expression of TDC and TYDC was shown to deplete the levels of Trp and Tyr, respectively, during seedling development. The creation of artificial metabolic sinks for Trp and Tyr also drastically affected the levels of phenylalanine, as well as those of the non-aromatic amino acids methionine, valine, and leucine. Transgenic seedlings also displayed a root-curling phenotype that directly correlated with the depletion of the Trp pool. Non-transformed control seedlings could be induced to display this phenotype after treatment with inhibitors of auxin translocation such as 2,3,5-triiodobenzoic acid or N-1-naphthylphthalamic acid. The depletion of aromatic amino acids was also correlated with increases in the activities of the shikimate and phenylpropanoid pathways in older, light-treated transgenic seedlings expressing TDC, TYDC, or both. These results provide in vivo confirmation that aromatic amino acids exert regulatory feedback control over carbon flux through the shikimate pathway, as well as affecting pathways outside of aromatic amino acid biosynthesis.

3-Deoxy-7-Phosphoheptulonate Synthase↗
PubMed2000

Synergistic insecticidal mode of action between sesquiterpene lactones and a phototoxin, alpha-terthienyl.

The synergistic insecticidal action of characteristic defensive substances produced by the plant family Asteraceae was investigated under controlled laboratory conditions. Sesquiterpene lactones isolated from Asteraceae that may form, through a Michael addition process, conjugates with glutathione were administered in a meridic diet to a herbivorous insect, Manduca sexta. By administering sesquiterpenes, variable in vivo reduced glutathione levels were observed in the insect larvae. When the Asteraceae-derived photooxidant alpha-terthienyl was co-administered, lipid peroxidation and larval mortality were significantly enhanced in the treated groups of insects with lowered in vivo glutathione levels.

Animals↗