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This paper proposes a new way of using forward selection of explanatory variables in regression or canonical redundancy analysis. The classical forward selection method presents two problems: a highly inflated Type I error and an overestimation of the amount of explained variance. Correcting these problems will greatly improve the performance of this very(More)
6 Distributions of species, animals or plants, terrestrial or aquatic, are influenced by numerous 7 factors such as physical and biogeographical gradients. Dominant wind and current directions 8 cause the appearance of gradients in physical conditions whereas biogeographical gradients can 9 be the result of historical events (e.g. glaciations). No spatial(More)
The changes in extracellular acetylcholine and glutamate levels were determined, during the course of seizures induced by soman, an irreversible inhibitor of acetylcholinesterase, in the CA1 hippocampal area of rats previously injected with atropine or normal saline into septum. The marked increases observed in soman-treated animals were abolished in rats(More)
The ability of relatively low doses of atropine, NBQX and TCP administered in combination to prevent or stop seizures induced by soman, was studied in rats. While these drugs injected together early after soman prevented the onset of seizures, their delayed concomitant administration after 5 or 30 min of epileptic activity only mildly attenuated the(More)
The protection afforded by TCP (thienylcylohexylpiperidine), a non-competitive blocker of N-methyl-D-aspartate (NMDA) receptors, against the seizures and lethality produced by 2 x LD50 of soman (62 micrograms/kg, sc), an irreversible inhibitor of cholinesterase, was studied in guinea-pigs. In the presence of additional anticholinergic medication(More)
Extracellular acetylcholine (ACh) levels were determined, by intracranial microdialysis, in medial septum, amygdala and hippocampus (CA1, CA3, dentate gyrus) of rats during seizures induced by systemic administration of soman (pinacolyl methylphosphonofluoridate), a potent inhibitor of acetylcholinesterase (AChE). In all septo-hippocampal areas a two phase(More)
The ability of NBQX, a potent antagonist of AMPA glutamatergic receptors, to prevent or stop seizures induced by the organophosphate soman, an irreversible inhibitor of AChE, was studied in rats. NBQX administered concomitantly with soman prevents the onset of seizures (ED50: 29.2 mg kg-1, i.p.). Administered 5 min after the onset of seizures, NBQX greatly(More)
TCP (N-[1-(2-thienyl)cyclohexyl]piperidine), A PCP (phencyclidine) derivative, has been shown to possess antiepileptic and neuroprotective efficacy against chemically induced seizures. However, it is known that other antagonists of the NMDA receptor impair spatial learning. This study was thus undertaken to explore the eventual effects of TCP on memory. The(More)
In rats poisoned with soman, an irreversible organophosphate anticholinesterase, acute changes in blood-brain barrier (BBB) permeability to proteins were investigated, using Evans Blue (EB)-labelled serum albumin and plasmatic gamma-immunoglobulin G (IgG) as indicators. Confirming previously published data, soman produced a conspicuous seizure-related and(More)
In rats poisoned with soman (s.c. 100 micrograms/kg), a potent inhibitor of cholinesterase (ChE), the numbers of dendritic spines of Golgi impregnated hippocampal pyramidal cells (CA1 sector) were evaluated within the first hour of the intoxication. Animals that experienced convulsions showed a rapid and striking decrease in the density of dendritic spines(More)