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Biomedical subjects

E Mahé

Publications and source records attributed to E Mahé.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Papular filariasis].

UNLABELLED: 'River blindness' is the main problem of onchocerciasis. Despite a high prevalence of onchocerciasis in endemic countries, cases of imported cutaneous or ocular onchocerciasis in France are rare. CASE REPORT: We report the case of a chronic papular onchodermatitis with voluminous lymphadenopathy in a Cameroonian child, resolving with a treatment of ivermectin. CONCLUSION: The main symptom of cutaneous onchocerciasis is pruritus, which symptom may alert physicians when dealing with patients who come from endemic countries for onchocerciasis. Cutaneous aspects may vary depending on length of exposure to antigens and immune responses by the host against microfilariae. Nowadays, onchocerciasis is treated with a single dose of ivermectin, which is sufficient for eye and cutaneous symptoms. However, this therapy is efficient only against microfilariae, and treatments have to be repeated many times to avoid relapses linked to persistence of adult worms.

Adolescent↗
PubMed2001

[Large hairy pigmented spots in neurofibromatosis type 1: an atypical form of neurofibromas].

INTRODUCTION: Large hairy pigmented spots have been observed in patients with neurofibromatosis type 1. In this study we tried to determine the nature and the frequency of these hairy pigmented spots in neurofibromatosis type 1. PATIENTS AND METHODS: In patients with neurofibromatosis type 1, hairy pigmented spots with a diameter more than 3 cm were systematically notified. Realisation of the biopsy of the spot was proposed to the patient. RESULTS: Among 614 patients with neurofibromatosis type 1, seven (1.1 p. 100) had a large hairy pigmented spot. Biopsy was realized in six cases. In five cases, diagnosis was superficial and plexiform neurofibroma, the 6(th) case was a Becker's nevus. CONCLUSION: Large hairy pigmented spot is a rare aspect of superficial and plexiform neurofibroma during neurofibromatosis type 1. A biopsy may be useful if it is necessary for the disorder diagnosis.

Adolescent↗
PubMed2000

Conserved aromatic residues in the transmembrane region VI of the V1a vasopressin receptor differentiate agonist vs. antagonist ligand binding.

Despite their opposite effects on signal transduction, the nonapeptide hormone arginine-vasopressin (AVP) and its V1a receptor-selective cyclic peptide antagonist d(CH2)5[Tyr(Me)2]AVP display homologous primary structures, differing only at residues 1 and 2. These structural similarities led us to hypothesize that both ligands could interact with the same binding pocket in the V1a receptor. To determine receptor residues responsible for discriminating binding of agonist and antagonist ligands, we performed site-directed mutagenesis of conserved aromatic and hydrophilic residues as well as nonconserved residues, all located in the transmembrane binding pocket of the V1a receptor. Mutation of aromatic residues of transmembrane region VI (W304, F307, F308) reduced affinity for the d(CH2)5[Tyr(Me)2]AVP and markedly decreased affinity for the unrelated strongly hydrophobic V1a-selective nonpeptide antagonist SR 49059. Replacement of these aromatic residues had no effect on AVP binding, but increased AVP-induced coupling efficacy of the receptor for its G protein. Mutating hydrophilic residues Q108, K128 and Q185 in transmembrane regions II, III and IV, respectively, led to a decrease in affinity for both agonists and antagonists. Finally, the nonconserved residues T333 and A334 in transmembrane region VII, controlled the V1a/V2 binding selectivity for both nonpeptide and cyclic peptide antagonists. Thus, because conserved aromatic residues of the V1a receptor binding pocket seem essential for antagonists and do not contribute at all to the binding of agonists, we propose that these residues differentiate agonist vs. antagonist ligand binding.

Amino Acid Sequence↗
PubMed1998

Correlation between binding affinity and necrosis-inducing activity of mutant AVR9 peptide elicitors.

The race-specific peptide elicitor AVR9 of the fungus Cladosporium fulvum induces a hypersensitive response only in tomato (Lycopersicon esculentum) plants carrying the complementary resistance gene Cf-9 (MoneyMaker-Cf9). A binding site for AVR9 is present on the plasma membranes of both resistant and susceptible tomato genotypes. We used mutant AVR9 peptides to determine the relationship between elicitor activity of these peptides and their affinity to the binding site in the membranes of tomato. Mutant AVR9 peptides were purified from tobacco (Nicotiana clevelandii) inoculated with recombinant potato virus X expressing the corresponding avirulence gene Avr9. In addition, several AVR9 peptides were synthesized chemically. Physicochemical techniques revealed that the peptides were correctly folded. Most mutant AVR9 peptides purified from potato virus X::Avr9-infected tobacco contain a single N-acetylglucosamine. These glycosylated AVR9 peptides showed a lower affinity to the binding site than the nonglycosylated AVR9 peptides, whereas their necrosis-inducing activity was hardly changed. For both the nonglycosylated and the glycosylated mutant AVR9 peptides, a positive correlation between their affinity to the membrane-localized binding site and their necrosis-inducing activity in MoneyMaker-Cf9 tomato was found. The perception of AVR9 in resistant and susceptible plants is discussed.

Amino Acid Sequence↗
PubMed1998

Solid-phase synthesis, conformational analysis, and biological activity of AVR9 elicitor peptides of the fungal tomato pathogen Cladosporium fulvum.

The race-specific peptide elicitor AVR9 of the fungal pathogen Cladosporium fulvum specifically induces a hypersensitive response in tomato genotypes carrying the complementary resistance gene Cf-9. The total chemical syntheses of this 28-residue AVR9 peptide containing three disulfide bonds, and of three mutant peptides [R8K]AVR9, [F10A]AVR9 and [F21A]AVR9, have been accomplished. The syntheses were carried out using a stepwise solid-phase approach based on tBoc chemistry. The disulfide bridges were formed by air oxidation. The correctness of the chemical structure of all folded synthetic peptides was confirmed by combined NMR and MS analyses. The biological activity and a number of physicochemical properties of folded synthetic AVR9 are identical to those of native fungal 28-residue AVR9. The overall conformations of the folded synthetic mutant peptides were comparable to that of synthetic wild-type AVR9 as demonstrated by NMR spectroscopy. Mutant [R8K]AVR9 showed a threefold higher, and mutant [F10A]AVR9 a threefold lower necrosis-inducing activity when compared to synthetic wild-type AVR9. However, mutant [F21A]AVR9 showed hardly any necrosis-inducing activity. Affinity for polyclonal antibodies raised against native fungal AVR9 is positively correlated with the necrosis-inducing activity of the synthetic AVR9 peptides ([R8K]AVR9 > wild-type AVR9 > [F10A]AVR9 > [F21A]AVR9).

Blotting, Western↗
PubMed1997

Properties of a new radioiodinated antagonist for human vasopressin V2 and V1a receptors.

A vasopressin receptor antagonist, [1-(beta-mercapto-beta,beta-pentamethylenepropionic acid), 2-o-ethyl-D-tyrosine, 4-valine, 9-tyrosylamide] arginine vasopressin (d(CH2)5[o-ethyl-D-Tyr2,Val4,Tyr-NH9(2)]AVP), has been prepared. This antagonist is a potent antiantidiuretic, antivasopressor and antioxytocic peptide with pA2 values of 7.69-7.94 and affinities of 1.12-11.0 nM. When radioiodinated at the phenyl moiety of the tyrosylamide residue at position 9, this peptide was demonstrated to bind to vasopressin V2 and V1a receptors with a dissociation constant of 0.22-0.75 nM. This ligand is a good tool for further studies on human vasopressin V2 receptor localization and characterization, when used in combination with a selective vasopressin V1a ligand.

Animals↗
PubMed1997

[Inferior blepharoplasty: the transconjunctival approach].

Described in 1924 by J. Bourguet, the transconjunctival approach seems to have experienced a resurgence of interest in recent North American publications. The incision, made under local anaesthesia along the inferior border of the tarsal cartilage, provides a plane of dissection which can be either preseptal, in which the approach to the bags is made through the septum as in the classical approach, or alternatively retroseptal, a route which respects the integrity of the septo-orbicular suspension, and allows a direct approach to th bags. Removal of fat should be limited to the excess tissue which protrudes when pressure is applied to the globe, using the orbital rim as a landmark. After haemostasis, closure is provided by means of a gathering stitch which is removed on the 4th day. The indications are young patients who present with bags with no excess of either skin or muscle (preseptal approach), dark-skinned patients in whom there is a risk of scarring (keloid), and older patients (retroseptal approach) who present with hyperlaxity of the septo-ligamentous mechanism, and in whom the "round eye" or an ectropion might result from a classical approach. In this last group, the excessive skin may be excised a minima without undermining. Finally, in cases of fat remnants after the classical approach, the transconjunctival approach offers an easy solution. Complications are extremely rare. It is for this reason that the transconjunctival approach is tending to become the standard approach for many modern authors.

Eyelid Diseases↗
PubMed1995

[Subperichondrial undermining in the anterior scoring otoplasty technique (Stenström)].

In the otoplasty described by Stenström (1963), the scoring of the cartilage needs a very cautious undermining of the perichondrium. The electronic microscopy states very precisely the connexion between the perichondrium, the cartilage and the skin of the helix: there is a fibroblast coat (with a high density of fibers and connective tissue) which stays close to the cartilage strut: the author describes a special elevator which allows to undermine more safely this layer without wearing away the dermis.

Adult↗
PubMed1992

[Retrospective study of 139 cases of epidermoid carcinoma of the upper respiratory and digestive tracts treated by induction chemotherapy with cisplatin-5FU. Influence of the result on the therapeutic protocol].

A retrospective study of 139 untreated staged III and IV epidermoid carcinomas of the upper aero digestive tract is reported concerning oropharynx, oral cavity, hypopharynx and larynx, all of them received as a first treatment, chemotherapy using a five days course of Cisplatinium (20 mg/m2/D) and 5FU (1,000 mg/m2/D). The aim of the trial was to determine: a) a free of disease survival and a global survival rate's increase, b) a more conservative treatment. The results of chemotherapy were clinically evaluated in two groups: Responders (a total or a more than 50% response), and no responders. The results were: on the tumor site: 64% responders (25% total response)--more in smaller lesion; on the lymphatic nodes: 54% responders (more in N1-N2). The results vary in inverse ratio to the stage of the lesion; usually, 2 cycles of chemotherapy are used but in case of efficiency: 2 to 6 cycles are provided increasing to 20% the rate of the total responders; toxicity of the drugs was neligible: 6 cases, 3 of them were renal insufficiency. The global survival rate at 3 months reaches 56.7%. The median line of survival reaches 32 months in responders reverse 15 months (NR); but there are no significant difference between the two groups concerning the recurrences, or the metastasis. The local treatment (after chemotherapy) decided in the 137 patients was surgery, in 40 cases and radiotherapy, in 97 cases (conservative treatment; 80%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Comparison of binding characteristics of endothelin receptors on subpopulations of astrocytes.

Astrocytes in primary culture originating from different brain areas of the mouse embryo (striatum, cerebral cortex and mesencephalon) were compared for their [125I]-Endothelin-1 (ET-1) binding characteristics, in terms of affinity, binding capacity and specificity. Our results indicate that astrocytes from mesencephalon express about twice as many receptors as astrocytes from striatum or cortex (149,000 +/- 9700 vs 63,700 +/- 5600 and 81,900 +/- 5300, respectively), with similar affinities. Specificity patterns for the various peptides of the endothelins/sarafotoxins family (ET-1, -2, -3; SRTXa, b, c) are comparable in the three subpopulations of astrocytes: ET-1, -2 and SRTXb exhibit higher affinities than SRTXa and SRTXc. In addition, ET-3 and SRTXc seem to discriminate between different subsets of [125I]-ET-1 binding sites in the three subpopulations.

Animals↗
PubMed1991

[Conchal cartilaginous delta graft in secondary or post-traumatic rhinoplasties].

The authors study several cases of surgical revision in post-traumatic or secondary rhinoplasty. Cartilaginous grafts with temporal fascia are recommended. The removal of ear cartilage is performed via a posterior approach for the concha cartilage associated with a septum or an alar cartilage removal. They describe the delta graft associating a concha cartilage supported by a prop (auricular or septal) to repair a defect of the middle or lower third of the pyramid.

Cartilage↗
PubMed1990

[Blepharoplasty: various technics in surgery of eyelid aging].

The authors reviewing their own experience of blepharoplasty (92 cases) over the last ten years, discuss the principal approaches used depending on the age of the patient, the amount of adipose tissue, the lower lid tarsal and muscular laxity and the quality of the skin excess. In the lower eyelid they emphasize the value of the transconjunctival approach in young and or coloured people and the use of a cutaneo-muscular flap in the classical technique. In the upper eyelid, they combine the skin excision with an orbicularis muscle strip and in old people with suspension of the lateral canthus. A wise selection of these various approaches avoids the rare complications (ectropion and scleral show) because blepharoplasty must be considered to be a "variable geometry" operation.

Adult↗
PubMed1989

Different technical approaches for blepharoplasty in eyelid rejuvenation surgery.

The authors have reviewed their clinical experiences with 92 cases of blepharoplasties treated during the past 10 years and discuss the principal approaches used, depending on the age of the patient, the amount of adipose tissue present, the degree of lower lid tarsal and muscle laxity present, and the quality of the skin excess encountered. On the upper eyelid, skin excision is combined with an orbicular muscle strip and in older patients a suspension of the lateral canthus. On the lower eyelid the transconjunctival approach is emphasized in young and or colored patients, using an undermined musculocutaneous flap in the classical technique. A good choice between these different approaches avoids the rare complications of ectropion and scleral show because the procedure used is considered to be a variable "geometric" operation.

Blepharoptosis↗