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E Biron

Publications and source records attributed to E Biron.

9 recordsLinked to original sources
PubMed2000

Conformational and orientation studies of artificial ion channels incorporated into lipid bilayers.

The conformational and orientation studies in lipid bilayers of 21 amino acid peptides bearing six crown ethers are reported. The compounds were designed to form artificial ion channels by stacking the crown rings, and were shown to be functional in bilayer membranes. We used Fourier transform infrared spectroscopy and CD spectropolarimetry to study the conformation of the peptides in solution and in lipid bilayers. These studies revealed that hexacrown peptides retain their alpha-helical conformation when incorporated in a lipid bilayer environment. Attenuated total reflectance spectroscopy was used to investigate the orientation of the peptides in a lipid bilayer. Results demonstrated that the peptides are not oriented at a fixed angle in membrane, but rather are in incorporation equilibrium between an active state parallel to the lipid chain and an inactive state adsorbed at the surface of the bilayer. From these results, we propose a model for the channel activity and the gating mechanism of these hexacrown peptides in bilayer membranes.

Animals↗
PubMed1999

Conformational analysis of biologically active truncated linear analogs of endothelin-1 using NMR and molecular modeling.

Some linear truncated analogs of endothelin-1 display potent agonistic activity at the ET(B) receptor, especially when the side chain of Trp21 is N-formylated. Then, the three-dimensional arrangements of six structurally reduced linear analogs, three formylated and three nonformylated, have been investigated by high resolution NMR spectroscopy and molecular modeling, in order to pinpoint the conformational features related to the biological activity. Two-dimensional double-quantum-filtered correlation spectroscopy (DQFCOSY), total correlation spectroscopy (TOCSY) and nuclear Overhauser enhancement spectroscopy (NOESY) were recorded and analyzed for each molecule. Interspatial distance constraints were derived from the intensity of the NOESY connectivities. The formation of hydrogen bonding was monitored from the temperature dependence of the NH chemical shifts. Molecular models calculated by means of distance geometry, simulated annealing and energy minimization, using the NMR constraints, strongly suggested a global elongated structure for the formylated analogs exhibiting biological activity, and a folded arrangement for the unformylated derivatives. Homology comparisons allowed the identification of a beta-turn-like folding of the C-terminal segment Asp18-Trp21 as a probable key-factor for activity.

Amino Acid Sequence↗
PubMed1985

[Pleural talc administration under thoracoscopy in the treatment of pneumothorax. Study of a series of 109 cases treated over a 3-year period].

There has recently been renewed interest in thoracoscopy. Among its indications we consider talc therapy for a pneumothorax particularly worthy of interest. We report the three year results obtained on a series of 109 pneumothoraces. The indication for thoracoscopy were considered either for a chronic pneumothorax (failure of drainage after 8 days) or for a recurrent pneumothorax. We perform this technique under local anaesthetic with talc therapy given direct vision on the macroscopic lesions encountered. Patients were in hospital for a mean of five days. The results were as follows: Lung appearance. Normal 19%-Dystrophic bullae and giant bullae 41%. blebs: 13%-a visible breach 14%-Diverse anomalies 13%. The immediate failures with talc numbered 6 (5%) each time from the chronic pneumothorax group. They were treated surgically. There were 7 recurrences after talc therapy, 5 were partial recurrences requiring no further treatment and two total relapses were surgically treated. The radiological sequelae appeared minimal. On 5 occasions pleural discomfort hindered the diaphragmatic movement, in the other cases the radiological sequelae consisted of discrete pleural thickening. 42 patients had respiratory function testing and no abnormalities were noted. The failures or recurrences in the talc treated patients were all in the recurrent pneumothorax and were only 13 cases (12%). Thus thoracoscopy is a treatment of choice in the treatment of recurrent pneumothorax, and often replaces surgery. In certain cases (pneumothorax in respiratory failure) it is only possible treatment.

Adolescent↗
PubMed1984

[Value of transparietal lung biopsy in the cytological diagnosis of bronchiolo-alveolar carcinomas of the lung. Apropos of 3 cases].

Bronchiolo-alveolar carcinoma is a rare primary lung tumour, which is difficult to diagnose by cytological techniques. This peripheral tumour, which develops on pre-existing alveolar walls, is not visible on bronchial endoscopy and brushing is often negative. The cellular material derived from aspiration or expectoration is characterised by numerous papillae, without any cytonuclear criteria of malignancy. The differential diagnosis is very difficult with reactive papillary hyperplasia and various forms of chronic bronchial inflammation. Transparietal aspiration lung biopsy facilitates the diagnosis of glandular carcinoma: the material examined corresponds to pathological tissue, as the biopsy is performed under image intensifier control. An inflammatory lesion is excluded by the rich cellularity and by the presence of architectural features of malignancy: cohesive and three-dimensional clumps of papillary tumour cells. The early cytological diagnosis of bronchiolo-alveolar and primary bronchiolar carcinomas of the lung by transparietal aspiration biopsy can allow the surgical cure of certain localised forms.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed1984

[Severe neurological toxicity (coma, convulsions, distal motor neuropathy) secondary to the association of accidental poisoning by isoniazid and a protocol containing high doses of vincristine].

Authors report the case of a 19 year old metastatic Ewing's sarcoma, prophylactically treated for suspected tuberculosis by Rifampicin and INH. Hepatic failure was induced by accidental overdose of INH. A high dose containing VCR protocol associated, lead to a coma with convulsions and severe motor peripheral neuropathy partially regressive. Neurological incidents of VCR, INH and their association are reviewed.

Adult↗
PubMedDate not supplied

[Value of thoracoscopy in the diagnosis of solid tumors extending into the pleural cavity].

Thoracoscopy examinations in 5 cases of solid tumors of the pleura: 1 case of Pancoast's and Tobias' tumors of neoplastic origin, 1 case of asbestosis-induced fibrohyaline plaques, and 2 cases of benign pleural tumors, 1 neurinoma emphasized the diagnostic value of thoracoscopy for tumors of this type. Direct visualization of the lesion is possible, its precise site and extent can be determined, and biopsy samples obtained for pathology under direct visual guidance.

Adult↗