Publications by authors named "Cadet J"

Intrastriatal injection of 6-hydroxydopamine causes significant depletion of dopamine which is associated with contralateral apomorphine-induced rotation in rats. Pretreatment with methylprednisolone (MP) causes almost complete elimination of the apomorphine-induced behavioral responses. In addition, there were significant differences between the lateralization effects of the neurotoxin on the levels of striatal dopamine.

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Rats were treated with the neurotoxin iminodipropionitrile (IDPN), which causes an irreversible movement disorder accompanied by axonal damage similar to that seen in vitamin E deficiency. Animals that received 2 g/kg vitamin E concurrently with 100 mg/kg IDPN for 10 days demonstrated a significantly reduced severity of IDPN-induced dyskinesia (as measured by vertical head movements) compared to animals that received IDPN alone. When animals were treated with 100 mg/kg IDPN for 10 days and then given either 2 g/kg vitamin E or an equivalent volume of sesame oil for 7 days, vitamin E produced a significant reduction in the severity of IDPN-induced dyskinesia.

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Continuing our study of the direct effects of gamma radiation on DNA and its model compounds, we have isolated and characterized quantitatively an important lesion formed by irradiating pyrimidine 2'-deoxyribonucleosides in frozen aqueous solution. We report here the formation of 5',6-cyclo-5,6-dihydropyrimidine nucleosides via hydrogen abstraction at C5' of the osidic moiety with subsequent intramolecular attack at C6 of the base. We have so far managed to isolate six of the possible eight diastereomers of 5',6-cyclo-5,6-dihydrothymidine, and all four possible 5',6-cyclo-5,6-dihydro-2'-deoxyuridines formed by irradiation of 2'-deoxycytidine.

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Met5-Enkephalin-Arg6-Gly7-Leu8 immunoreactivity was quantitated in both rat and human cerebrospinal fluid (CSF) by radioimmunoassay with a carboxy-terminal directed antiserum. The immunoreactivity in CSF was chromatographically characterized in both species and was found to consist almost exclusively of high molecular weight forms. In human CSF there was approximately 300 fmol/ml and in the rat 1,500 fmol/ml of immunoreactivity.

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The near-UV-induced photoreaction of the bifunctional 8-methoxypsoralen (8-MOP) with 2'-deoxyadenosine (dAdo) was investigated in the dry state. Four main monoadducts of 8-MOP to 2'-deoxyadenosine were separated by high performance liquid chromatography and subsequently characterized by soft ionization mass spectrometry (fast atom bombardment and plasma desorption mass spectrometries) and extensive 1H NMR analysis including nuclear Overhauser effect (NOE) measurements. These new types of furocoumarin-nucleic acid component which appear to be specific to 2'-deoxyadenosine were shown to result from recombination of the 3,4-dihydropyron-4-yl radical of 8-MOP with 2'-deoxyadenosyl radical either at the 1' or the 5' position.

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The mechanisms by which intrastriatal grafts of chromaffin tissue alleviate the signs of clinical and experimental parkinsonism remain elusive. In the present report, we have demonstrated that, in conjunction with intraventricular infusion of nerve growth factor (NGF), ventricular grafts of either non-chromaffin or adrenal medullary tissue are equally effective in reducing apomorphine-induced circling in rats whose substantia nigra have been permanently lesioned with 6-hydroxydopamine. These treatments were much more effective than implantation of adrenal medulla without NGF.

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Parkinson's disease and Alzheimer's disease are both neuro-degenerative disorders which affect a large number of the older population. Schizophrenia is a neuropsychiatric illness with a variable course which, sometimes, results in a deteriorated state, the so-called schizophrenic burnout. Although the pathogenesi(e)s of these syndromes is (are) not known, it has been suggested that the reported neuropathological findings are concentrated in neuronal systems located within the isodendritic core of the brainstem.

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Many DNA repair enzyme activities are present in both prokaryotic and eukaryotic organisms. Among these are DNA exo- and endonucleases and DNA glycosylases which remove oxidatively damaged portions of the DNA molecule, thereby initiating excision-repair. The existence of these enzymes may be taken as evidence that cellular DNA is continuously subject to endogenous oxidative stress.

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Three out of four possible photodimers of thymidylyl(3'-5')thymidine monophosphates (i.e., cis-syn, 6-4, and one of the trans-syn) and two structural isomers (i.

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Chronic administration of iminodipropionitrile (IDPN) in rats causes a persistent behavioral syndrome which consists of lateral and vertical twitches, random circling, and hyperactivity. These abnormalities are very similar to those induced by the acute injection of serotonin (5-HT) agonists. The present study reveals significant increases in the levels of 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) in the caudate-putamen and in the nucleus accumbens during treatment with IDPN.

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Twenty-four patients with schizophrenia and 14 normal control subjects underwent magnetic resonance imaging scans using a 0.5-tesla scanner and 600-ms inversion recovery technique. A midsagittal section and twelve 1-cm coronal sections beginning at the frontal pole were obtained, and linear, area, and signal intensity measurements were made on nine brain regions.

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Free radicals are highly toxic compounds which can react with a number of molecules such as glycoproteins or amino acids. These reactions can lead to the denaturation of proteins, destabilization of cellular membrane and eventually, cell death. Free radicals have been recently implicated in the pathogenesis and clinical course of a number of neuropsychiatric disorders including aging of the central nervous system (CNS), schizophrenia, and the development of tardive dyskinesia during chronic use of neuroleptics.

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The effects of the specific serotonin2 antagonist ketanserin on the persistent lateral head shakes, vertical neck dyskinesia, and the random circling behaviors induced by iminodipropionitrile were evaluated. Ketanserin inhibited all these aspects of the behavioral syndrome at all doses tested. These results add further evidence for the involvement of the serotonin system in some of the components of the iminodipropionitrile-induced dyskinetic syndrome.

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Chronic administration of IDPN leads to the development of a persistent syndrome which is characterized by lateral and vertical neck dyskinesias, random circling behaviors, and locomotor hyperactivity. Although the dihydropyridine (DHP) calcium channel antagonist nifedipine inhibited all aspects of the syndrome, lateral head dyskinesias (laterocollis) and circling abnormalities were the most significantly affected signs. Dysregulation of calcium-dependent processes might be involved in the pathogenesis of the IDPN-induced dyskinetic abnormalities and clinical disorders of movement in humans.

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Chronic treatment with iminodipropionitrile (IDPN) causes a behavioral syndrome characterized by lateral and vertical neck dyskinesias, hyperactivity, random circling, and increased startle response (the "ECC syndrome"). The effects of the neurotoxin on norepinephrine (NE), dopamine (DA), and their metabolites were evaluated in the hypothalamus and the striatum of IDPN-treated animals. Urinary excretion of the amines was also measured.

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Acute administration of alpha-benzyl-N-methylphenethylamine (ABNMP) induces lateral heavings, straub tail, backward locomotion, and hindlimb abduction-which are all components of the serotonin (5-HT) syndrome. Ketanserin, a 5-HT-2 receptor antagonist and pretreatment with the 5-HT neurotoxin parachlorophenylalanine (PCPA) attenuated the manifestation of these behavioral abnormalities. These results suggest that ABNMP may cause an acute release of 5-HT similar to that elicited by para-chloroamphetamine.

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One of the major problems associated with long-term neuroleptic treatment is persistent tardive dyskinesia (TD), for which there is no satisfactory treatment. We have recently proposed that some cases of TD are associated with neuronal dysfunction resulting from excess free radical production occurring during catecholamine metabolism. We therefore decided to assess the efficacy of a powerful free radical scavenging agent, alpha-tocopherol (vitamin E), on the clinical signs of TD.

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Chronic administration of iminodipropionitrile (IDPN) to rats causes a persistent behavioral syndrome consisting of lateral and vertical twitches, random circling, hyperactivity, and increased startle response. These abnormalities are almost identical to those seen after acute injection of serotonin agonists and hallucinogenic drugs. The results of our quantitative autoradiographic localization studies comparing the distribution of 125I-lysergic acid diethylamide (LSD)-labeled 5-HT-2 serotonin receptors in slide-mounted sections of IDPN- and saline-treated revealed a number of changes in 5-HT-2 receptors in the brain of IDPN-treated animals.

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Membranes were prepared from area 8 of human frontal cortex harvested from five controls and five opiate addicts. Psychotomimetic binding sites were assayed using tritiated 1-(1-[2-thiethyl]cyclohexyl)piperidine ([3H]TCP) to label phencyclidine binding sites and 1,3-Di(2-[5-3H]tolyl)guanidine ([3H]DTG) to label the "haloperidol-sensitive sigma binding site." The results demonstrated no significant differences between the control and experimental groups, suggesting that in the region of the human brain sampled in this study, chronic abuse of opiates is not accompanied by alterations in psychotomimetic binding sites.

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A dental appliance with a spring used to induce a mesial movement of the lower molars was placed in the mouth of two groups of golden hamsters, one control and the other submitted to the hyperglucidic diet of Keyes and Jordan. The analysis and histological comparison of the tissue reactions showed important differences in both groups. The alveolar wall remodeling in the experimental group was inhibited as well as the resorption of the hyaline zones.

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Chronic treatment with IDPN causes a persistent behavioral syndrome which is reminiscent of the head shakes, backward locomotion, and hyperactivity observed after acute injection of 5-HT agonists in rodents. Evaluation of the characteristics of 5-HT receptors, using mianserin to label 5-HT-2 receptors, revealed a significant increase in the number of binding sites in the cortices of rats which demonstrated the IDPN-induced syndrome. There was an associated decrease in the affinity of the receptors.

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