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See detailElectrooxidation Potential as a Tool in the Early Screening for New Safer Clozapine-Like Analogues
Mouithys-Mickalad, Ange ULg; Kauffmann, J. M.; Petit, C. et al

in Journal of Medicinal Chemistry (2001), 44(5), 769-76

The chemical modification of clozapine (1) has permitted the finding of new analogues, e.g., olanzapine (2), quetiapine (3), 5-(4-methylpiperazin-1-yl)-8-chloropyrido[2,3-b][1,5]benzoxazepine fumarate (9 ... [more ▼]

The chemical modification of clozapine (1) has permitted the finding of new analogues, e.g., olanzapine (2), quetiapine (3), 5-(4-methylpiperazin-1-yl)-8-chloropyrido[2,3-b][1,5]benzoxazepine fumarate (9), with a clinical or psychopharmacological profile similar to that of clozapine. However, when developing new derivatives, the designers are discouraged by the development of clozapine-induced agranulocytosis. Different researchers have raised the role played by the oxidizability of the molecule in such a deleterious effect. In the present paper, we examined the oxidation profile (direct scavenging abilities, efficacy in inhibiting lipid peroxidation, and electrooxidation potential) of newly developed methoxy and trifluoromethylsulfonyloxy analogues related to clozapine, some of them being described as putative antipsychotic. The oxazepine derivative 7, unlike the other diazepine derivatives (6, 10--12), was not readily oxidized. Using a statistical predictive model for hematotoxicity previously described, 7 was found in the cluster of potentially nontoxic compounds while diazepine derivatives 6 and 10-12 were classified as potentially toxic compounds. Among these original compounds, 7, which presents a preclinical clozapine-like profile and a low sensitivity to oxidation, could be a promising antipsychotic candidate with low side effects. Considering the tricyclic derivatives examined so far, some elements of structure-oxidation relationship (SOR) might be pointed out. Regarding the nature of the tricyclic ring substituent, from the most to the least sensitive to oxidation, the sequence was as follows: HO > Cl > CH(3)O > CF(3)SO(2)O. The nature of the tricyclic ring influenced also the sensitivity to oxidation; the diazepine moiety appeared to be the most reactive ring compared to oxa- and thiazepine congeners. These parameters could be advantageously integrated in the early design of new safer clozapine-like analogues. [less ▲]

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See detailElectropherogram Comparison By Computer
Wathelet, Bernard ULg; Marlier, M.

in Chemometrics and Intelligent Laboratory Systems (1988), 4(4),

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See detailElectrophile induced rearrangement of 1-alkynylaluminium ate complexes
Debuigne, Antoine ULg; Gérard, Julien; Hevesi, Làszlo

in Tetrahedron Letters (1999), 40(32), 5943-5944

The title species have been shown to rearrange under the influence of the electrophile PhSCl to give tetrasubstituted vinylaluminium compounds protonolysis of which led to the corresponding vinyl sulfides ... [more ▼]

The title species have been shown to rearrange under the influence of the electrophile PhSCl to give tetrasubstituted vinylaluminium compounds protonolysis of which led to the corresponding vinyl sulfides in a highly stereoselective manner. [less ▲]

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See detailElectrophysiologic contribution to cervical pain
WANG, François-Charles ULg; TOMASELLA, Marco ULg

in Revue du Rhumatisme et des Maladies Osteo-Articulaires (2008)

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See detailElectrophysiologic evaluation of the phrenic nerve-diaphragm pathway in an intact conscious calf model
Desmecht, Daniel ULg; Linden, Annick ULg; Lekeux, Pierre ULg

in American Journal of Veterinary Research (1995), 56(5), 545-554

Owing to technical and ethical limitations, a substantial part of the knowledge about the pathophysiologic mechanism of the human diaphragm has been obtained from studies in which phrenic nerve activation ... [more ▼]

Owing to technical and ethical limitations, a substantial part of the knowledge about the pathophysiologic mechanism of the human diaphragm has been obtained from studies in which phrenic nerve activation was usually carried out by direct surgical exposure of the nerves in the neck of deeply anesthetized, mechanically ventilated animals. Novel information has been gleaned from such studies, but the restrictive conditions under which it was collected preclude reliable extrapolation. We, therefore, addressed the question of whether accurate electrophysiologic evaluation of the phrenic nerve-diaphragm pathway can be performed in intact, nonanesthetized calves. Transjugular phrenic activation was well tolerated, safe, specific, and able to achieve constant symmetric and supramaximal phrenic stimulations during prolonged periods. Eighteen noninvasive cutaneous and esophageal reception circuits were tested for their ability to record the diaphragmatic evoked potential. In addition, they were compared for specificity and reproducibility of the recorded potentials during prolonged periods of tidal or stimulated respiration. The best diaphragmatic potential was recorded from surface electrodes attached to the skin of the ninth and tenth intercostal spaces, using a xyphoidian reference. We describe a method that allows easy, longterm, and reliable electrophysiologic evaluation of the phrenic nerve-diaphragm pathway in intact, conscious calves. It is hoped that such a model will produce relevant novel information regarding pathophysiology of the diaphragm. [less ▲]

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See detailElectrophysiologic recurrent laryngeal nerve monitoring during thyroid and parathyroid surgery:international standards guideline statement
Randolph, Gregory; Dralle, Henning; Abdullah, hisham et al

in Laryngoscope (2011), 121

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See detailElectrophysiological And Behavioral Activity Of Secondary Metabolites In The Confused Flour Beetle, Tribolium Confusum
Verheggen, François ULg; Ryne, C.; Olsson, P.-O. C. et al

in Journal of Chemical Ecology (2007), 33(3), 525-539

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See detailElectrophysiological and behavioral responses of the multicolored asian lady beetle, Harmonia axyridis pallas, to sesquiterpene semiochemicals
Verheggen, François ULg; Fagel, Quentin; Heuskin, Stéphanie ULg et al

in Journal of Chemical Ecology (2007), 33(11), 2148-2155

The role of two volatile sesquiterpenes, (E)-beta-farnesene and (-)-beta-caryophyllene, in the chemical ecology of the multicolored Asian lady beetle, Harmonia axyridis Pallas, was investigated by using ... [more ▼]

The role of two volatile sesquiterpenes, (E)-beta-farnesene and (-)-beta-caryophyllene, in the chemical ecology of the multicolored Asian lady beetle, Harmonia axyridis Pallas, was investigated by using both electrophysiological and behavioral techniques. (E)-beta-Farnesene is the major component of the alarm pheromone of most aphid species, which are preyed on by H. axyridis. (-)-beta-Caryophyllene was previously isolated from the headspace volatiles above overwintering and aggregated H. axyridis females. These sesquiterpenes elicited significant electroantennogram (EAG) activity from both H. axyridis male and female antennae. In a four-arm olfactometer, male and female H. axyridis were highly attracted toward (E)-beta-farnesene, whereas only males were attracted to (-)-beta-caryophyllene. In a bioassay technique that used a passively ventilated plastic box, both male and female H. axyridis aggregated in the (-)-beta-caryophyllene-treated side of the box. These results support the potential usefulness of (E)-beta-farnesene and (-)-beta-caryophyllene in push-pull strategies that use H. axyridis as a biological control agent in aphid-infested sites or to control this new urban pest in residential structures. [less ▲]

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See detailElectrophysiological and behavioural responses of Thanatophilus sinuatus F. (Coleoptera: Silphidae) to selected cadaveric volatile organic compounds
Dekeirsschieter, Jessica ULg; Frederickx, Christine ULg; Lognay, Georges ULg et al

in Journal of Forensic Sciences (2013)

Soon after death, carcasses release volatile chemicals that attract carrion insects including Silphidae. Nevertheless, it is not known which chemical cues are involved in the attractiveness of the carcass ... [more ▼]

Soon after death, carcasses release volatile chemicals that attract carrion insects including Silphidae. Nevertheless, it is not known which chemical cues are involved in the attractiveness of the carcass. So far, little information is available on the chemical ecology of carrion beetles, particularly concerning the subfamily of Silphinae. The biological role of selected cadaveric volatile organic compounds including: dimethyldisulfide (DMDS), butan-1-ol, n-butanoic acid, indole, phenol, p-cresol, putrescine, and cadaverine on the silphine species, Thanatophilus sinuatus Fabricius, was investigated by using both electrophysiological and behavioural techniques. Among the tested cadaveric compounds, butan-1-ol and DMDS elicited the strongest EAG from both T. sinuatus male and female antennae. In a two-arm olfactometer, males and females were significantly attracted to dimethyldisulfide (DMDS) for both tested doses, whereas only males were attracted to p-cresol at 100 ng. Putrescine was repellent to males at the dose of 1 µg [less ▲]

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See detailElectrophysiological behavior of Purkinje cells and motor coordination in calretinin knock-out mice
Cheron, Guy; Schurmans, Stéphane ULg; Lohof, Ann et al

in Progress in Brain Research (2000), 124

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See detailElectrophysiological characterization of the SK channel blockers methyl-laudanosine and methyl-noscapine in cell lines and rat brain slices
Scuvée-Moreau, Jacqueline ULg; Boland, André ULg; Graulich, Amaury ULg et al

in British Journal of Pharmacology (2004), 143(6), 753-764

We have recently shown that the alkaloid methyl-laudanosine blocks SK channel-mediated afterhyperpolarizations (AHPs) in midbrain dopaminergic neurones. However, the relative potency of the compound on ... [more ▼]

We have recently shown that the alkaloid methyl-laudanosine blocks SK channel-mediated afterhyperpolarizations (AHPs) in midbrain dopaminergic neurones. However, the relative potency of the compound on the SK channel subtypes and its ability to block AHPs of other neurones were unknown. Using whole-cell patch-clamp experiments in transfected cell lines, we found that the compound blocks SK1, SK2 and SK3 currents with equal potency: its mean IC(50)s were 1.2, 0.8 and 1.8 microM, respectively. IK currents were unaffected. In rat brain slices, methyl-laudanosine blocked apamin-sensitive AHPs in serotonergic neurones of the dorsal raphe and noradrenergic neurones of the locus coeruleus with IC(50)s of 21 and 19 microM, as compared to 15 microM in dopaminergic neurones. However, at 100 microM, methyl-laudanosine elicited a constant hyperpolarization of serotonergic neurones of about 9 mV, which was inconsistently (i.e. not in a reproducible manner) antagonized by atropine and hence partly due to the activation of muscarinic receptors. While exploring the pharmacology of related compounds, we found that methyl-noscapine also blocked SK channels. In cell lines, methyl-noscapine blocked SK1, SK2 and SK3 currents with mean IC(50)s of 5.9, 5.6 and 3.9 microM, respectively. It also did not block IK currents. Methyl-noscapine was slightly less potent than methyl-laudanosine in blocking AHPs in brain slices, its IC(50)s being 42, 37 and 29 microM in dopaminergic, serotonergic and noradrenergic neurones, respectively. Interestingly, no significant non-SK effects were observed with methyl-noscapine in slices. At a concentration of 300 microM, methyl-noscapine elicited the same changes in excitability in the three neuronal types than did a supramaximal concentration of apamin (300 nM). Methyl-laudanosine and methyl-noscapine produced a rapidly reversible blockade of SK channels as compared with apamin. The difference between the IC(50)s of apamin (0.45 nM) and methyl-laudanosine (1.8 microM) in SK3 cells was essentially due to a major difference in their k(-1) (0.028 s(-1) for apamin and >or=20 s(-1) for methyl-laudanosine). These experiments demonstrate that both methyl-laudanosine and methyl-noscapine are medium potency, quickly dissociating, SK channel blockers with a similar potency on the three SK subtypes. Methyl-noscapine may be superior in terms of specificity for the SK channels. [less ▲]

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