PubMed Health⌕ Search

Biomedical subjects

P Lavanchy

Publications and source records attributed to P Lavanchy.

10 recordsLinked to original sources
PubMed2000

Steady-state fully noninductive current driven by electron cyclotron waves in a magnetically confined plasma

A steady-state, fully noninductive plasma current has been sustained for the first time in a tokamak using electron cyclotron current drive only. In this discharge, 123 kA of current have been sustained for the entire gyrotron pulse duration of 2 s. Careful distribution across the plasma minor radius of the power deposited from three 0. 5-MW gyrotrons was essential for reaching steady-state conditions. With central current drive, up to 153 kA of current have been fully replaced transiently for 100 ms. The noninductive scenario is confirmed by the ability to recharge the Ohmic transformer. The dependence of the current drive efficiency on the minor radius is also demonstrated.

Journal Article↗
PubMed1985

5,6-Diaryl-2,3-dihydroimidazo[2,1-b]thiazoles: a new class of immunoregulatory antiinflammatory agents.

A series of substituted 5,6-diaryl-2,3-dihydroimidazo[2,1-b]thiazoles were synthesized and evaluated in the rat adjuvant-induced arthritis and mouse oxazolone-induced contact sensitivity assays to determine the potential of these compounds for use as immunoregulatory antiinflammatory agents. This class of compounds was derived by combining salient structural features of the antiinflammatory agent flumizole and the immunoregulatory drug levamisole. Unlike the latter two, a number of compounds in the target series were found to possess the desired combination of activities. Exploration of structure-activity relationships in the adjuvant-induced arthritic rat assay revealed that optimal potency was exhibited by symmetrically substituted 5,6-diaryl compounds having one of the following alkyl heteroatom or halogen functions at the para position: methoxy, ethoxy, methylthio, N-ethyl-N-methylamino, fluoro, or chloro. Scrambling of these two substituent classes to yield the asymmetrically substituted 5,6-diaryl compounds resulted in potent activity only with the 5-alkyl heteroatom, 6-halo-substituted regioisomers. However in the oxazolone-induced contact sensitivity assay, no consistent relationship of variation in activity with structural change was apparent. The initial target compound 5,6-bis(4-methoxyphenyl)-2,3-dihydroimidazo[2,1-b]thiazole (1) was compared with its progenitors in additional models of inflammation and immunoregulation.

Animals↗
PubMed1985

N-[2-hydroxy-5-[2-(methylamino)ethyl]phenyl]methanesulfonamide. A potent agonist which releases intracellular calcium by activation of alpha 1-adrenoceptors.

N-[2-Hydroxy-5-[2-(methylamino)ethyl]phenyl]methanesulfonamide (SK&F 102652) has been prepared and characterized pharmacologically. It is a potent agonist with an EC50 of 25 nM at alpha 1-adrenoceptors as determined in the isolated perfused rabbit ear artery. On the presynaptic alpha 2-adrenoceptors of the guinea pig atrium it was considerably weaker, demonstrating an EC50 for inhibition of neurotransmission of 1200 nM and thus an overall alpha 1/alpha 2 selectivity ratio of greater than or equal to 48. In the vascular smooth muscle of the canine saphenous vein an EC100 concentration of this agonist in the presence of zero external Ca2+ induced 37.9 +/- 1.4% of the maximal contractile response due to this agent while the endogenous ligand norepinephrine evoked only 14.5 +/- 0.4% of the maximum. In the presence of low (1 microM) external calcium, this agent produced 78.3 +/- 5.3% of maximum while norepinephrine gave 45.3 +/- 7.4%. This agent produces alpha 1-adrenoceptor-mediated contraction primarily by release of intracellular Ca2+ and should provide a useful tool for characterizing alpha 1-receptor subtypes.

Animals↗
PubMed1981

Treatment of cystinosis with cysteamine. A pilot study determining dose and form of application.

A pilot study with cysteamine treatment was performed in three children with the nephropathic form of cystinosis. Two children underwent renal transplantation shortly before treatment. The aim of the study was to find a practicable form of application and a corresponding effective dose. Cysteamine in gelatine capsules together with 0.2% silicic acid as a dessicator turned out to be the most acceptable galenic form, compared to sirup or suppositories. Among three dosage regimens, the dosage of 50 mg/kg/day is effective as judged by the leucocyte cystine content, even if given in only three doses per day. No side effects of the cysteamine treatment (even at a dose of 90 mg/kg/day) were noted. Whether this treatment is preventing progression of disease will have to be examined either in transplanted patients by measuring non-renal parameters or in very young infants with cystinosis whose kidneys are not damaged yet.

Child, Preschool↗
PubMed1973

Synthesis of Paramecium surface proteins. I. Puromycin insensitive amino acid incorporation.

The synthesis of a surface protein has been studied in Paramecium through double-labeling experiments using [(14)C]- and [(3)H]leucine-labeled bacteria as the source of radioactive amino acid. Over a 4-5 h incubation period, the turnover rate was found to be higher than that of overall cell protein. In addition, the initial label is apparently utilized during the chase period, being incorporated into protein via a puromycin insensitive pathway.

Amino Acids↗