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N De Klippel

Publications and source records attributed to N De Klippel.

15 recordsLinked to original sources
PubMed1997

Early outcome in acute ischemic stroke is not influenced by the prophylactic use of low-dose aspirin.

Aspirin reduces the occurrence of ischemic strokes. In some prophylactic trials it was suggested that aspirin might also lessen stroke severity, and hence improve outcome in patients sustaining an ischemic stroke. We examined stroke severity (by using the Mathew scale) and early outcome (Barthel index and mortality on day 21) in 91 patients with an acute (< 24 h) ischemic stroke in the territory of the middle cerebral artery. Twenty-seven patients were taking low-dose aspirin (100 or 200 mg/day) prior to their stroke, and 64 were not using antiplatelet drugs. There were no significant differences in baseline stroke severity, early (21 days) mortality or early disability between the two groups. The results of this small study suggest that the use of low-dose aspirin prior to an ischemic stroke does not influence the severity of that stroke and early outcome.

Aged↗
PubMed1995

Tonic GABA-ergic modulation of striatal dopamine release studied by in vivo microdialysis in the freely moving rat.

GABAA and GABAB receptor agonists and antagonists were administered locally in the striatum of intact and kainic acid lesioned rats. (+/-)-Baclofen, a GABAB receptor agonist, significantly decreased the level of extracellular dopamine in the striatum of intact rats. (+/-)-Phaclofen, a GABAB receptor antagonist, increased the level of extracellular dopamine in the striatum of intact rats and to a lesser extent in the striatum after kainic acid lesion. Pregnanolone (5 beta-pregnan-3 alpha-ol-20-one), a positive allosteric modulator of the GABAA receptor, significantly decreased the level of extracellular dopamine in intact rats. (-)-Bicuculline, a GABAB receptor antagonist, increased the level of extracellular dopamine in the striatum of intact rats, but failed to increase the level of extracellular dopamine after kainic acid lesion. The release of extracellular dopamine, due to infusion of phaclofen or bicuculline, was totally suppressed by tetrodotoxin. These results support a direct influence of GABA on the dopaminergic terminals via presynaptic GABAB receptors, while the effects via the GABAA receptor seem to be postsynaptic and mediated by striatal interneurons or the striatonigral feedback loop.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1994

Biotransformation of locally applied L-dopa in the corpus striatum of the hemi-parkinsonian rat studied with microdialysis.

Microdialysis was used to study the biotransformation of L-dopa in intact and denervated striata of rats with a unilateral 6-hydroxydopamine (6-OHDA) lesion of the substantia nigra. Microdialysis probes were placed in the intact and in the denervated striatum. Observations were then made on freely moving rats. Extracellular levels of dopamine, 3,4-dihydroxyphenylacetic acid (DOPAC) and 4-hydroxy-3-methoxyphenylacetic acid (homovanillic acid; HVA) were monitored before, during and after the local administration of L-dopa via the microdialysis probe for 20 min. A dose-dependent increase in extracellular dopamine levels was seen in intact striatum after application of L-dopa in concentrations ranging between 100 nmol/l and 10 mumol/l. In the denervated striatum, the severity of the lesion influenced dopamine formation, so that no dose-effect relation could be established. The effects of the continuous intra striatal infusion of nomifensine, tetrodotoxin or benserazide on the L-dopa-induced dopamine outflow revealed that in the intact striatum this dopamine release is mainly voltage dependent. It was concluded that in the denervated striatum other cells of non-neuronal origin and containing aromatic L-amino acid decarboxylase make a major contribution to the increase in extracellular dopamine levels. Furthermore, L-dopa itself shows no dopamine-releasing properties, at least under the present experimental conditions.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1994

Bromocriptine therapy in multiple sclerosis: an open label pilot study.

Bromocriptine suppresses the duration and severity of clinical signs of experimental allergic encephalitis, which is considered as an animal model for multiple sclerosis (MS). We conducted an open pilot study with 2.5 mg of bromocriptine two times a day on 18 patients with clinically or laboratory-supported definite MS (10 with the relapsing-remitting form and eight with the chronic progressive form). After 1 year of treatment, 14 of the 15 patients who completed the study showed disease progression as evidenced by one or more of the following parameters: worsening of the EDSS score, clinical relapses, appearance of new lesions on MRI of the brain and brainstem, or increased latencies of visual or auditory evoked responses. These findings indicate that bromocriptine does not completely suppresses ongoing disease activity in patients with multiple sclerosis.

Adult↗
PubMed1994

The European Stroke Scale.

BACKGROUND AND PURPOSE: For detecting therapeutic effect and matching of treatment groups in stroke trials, a scale that meets the clinimetric criteria is of the utmost importance. METHODS: The European Stroke Scale consists of 14 items selected for their specificity and their prognostic value. It is designed for patients with middle cerebral artery stroke. Interrater reliability, internal consistency, and time for completion were investigated in 74 patients. Intrarater reliability was studied in 38 patients. To establish concurrent validity, two trials were performed in 20 and 44 patients. The scale was correlated with the MCA Neurological Scale, the Canadian Stroke Scale, the Scandinavian Stroke Scale, the Barthel Index, and the Rankin Scale. Correlations were calculated by means of Spearman's correlation coefficient. The trial in 44 patients also investigated the prognostic validity of the scale for 1-month and 8-month neurological, functional, and handicap status. These data were analyzed by linear regression. RESULTS: Interrater (kappa value range, 0.62 to 0.85) and intrarater (kappa value range, 0.65 to 1.00) reliability for each item was good, and internal consistency was excellent (Cronbach's alpha coefficient, 0.92). Mean time for completion was 8.2 minutes (range, 4 to 14 minutes). Correlations of the European Stroke Scale with other neurological scales ranged from 0.93 to 0.95. The correlation with the Barthel Index and the Rankin Scale was 0.84 and -0.86. The R2 values for prognostic validity ranged from 0.45 to 0.81 (P < or = .0001). CONCLUSIONS: The European Stroke Scale has been developed according to the clinimetric criteria.

Adult↗
PubMed1993

Effect of M1- and M2-muscarinic drugs on striatal dopamine release and metabolism: an in vivo microdialysis study comparing normal and 6-hydroxydopamine-lesioned rats.

Microdialysis was used to study the effect of M1 and M2 selective agonists and antagonists on striatal dopamine release and metabolism. Microdialysis probes were implanted, under anesthesia, in the left and the right striatum of the normal rats and in the normal and denervated striatum of the nigral 6-hydroxydopamine-lesioned rats. Dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) were determined by liquid chromatography and electrochemical detection. The different drugs were infused through the dialysis probe during 40 min. Pirenzepine (5 microM), a selective M1 antagonist, produced a significant decrease in DA release in the normal and the 6-hydroxydopamine-lesioned rats, with no significant difference between both groups. Methoctramine, a selective M2 antagonist, produced a dose-dependent increase in DA release between 20 and 200 microM in the normal rats, with no significant effect on DOPAC and HVA. Infusing 75 microM methoctramine produced a significant increase in DA release with a more pronounced effect in the intact animals compared to the 6-hydroxydopamine-lesioned animals. The non-selective agonist carbachol produced a decrease in dopamine release after infusion of 50 microM (M2 effect) and an increase in dopamine release after infusion of 50 mM (M1 effect) in the normal rats. Infusing 50 microM carbachol in the denervated striatum, produced a slight increase in DA release. Our data suggest that presynaptic M1-muscarinic receptors enhance and M2-muscarinic receptors inhibit DA release in the striatum of the rat; and that 3 weeks after 6-hydroxydopamine lesioning there may be a normalisation of the number of M1-receptors with a loss of M2-receptors at the denervated side.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1992

Serum concentrations of vitamins A and E and early outcome after ischaemic stroke.

Formation of free radicals and subsequent lipid peroxidation may have an important role in tissue injury and neuronal cell death after cerebral ischaemia. We conducted a prospective, controlled study to determine whether the endogenous antioxidant vitamins A and E had a protective function in acute ischaemic stroke. The study population consisted of 80 patients seen at the Free University Hospital in Brussels. Entry criteria were occurrence of sudden focal neurological deficit lasting more than 3 h; deficit due to acute ischaemia in the territory of the middle cerebral artery; and investigation within 24 h of onset of the episode. Outcome was assessed within the first 21 days. 80 controls matched for age and sex had various neurological disorders other than acute ischaemia. Serum concentrations of vitamins A and E were similar in the study and control groups. In the study population a serum vitamin A concentration higher than the mean of 2.27 mumol/l was associated with a higher frequency of complete recovery within the first 24 h (p less than 0.05), decreased mortality (p = 0.038), and a better outcome as assessed by the Mathew scale of neurological deficit (p less than 0.03) and the Barthel index. There was no significant difference in outcome between patients with vitamin E concentrations above or below the mean of 35.3 mumol/l. Our results suggest a beneficial effect of a high serum vitamin A concentration on early outcome in ischaemic stroke.

Aged↗
PubMed1992

High-performance liquid chromatography with electrochemical detection for the determination of levodopa, catecholamines and their metabolites in rat brain dialysates.

A high-performance liquid chromatographic assay with electrochemical detection is described for the simultaneous determination of levodopa, 3-O-methyldopa, dopamine, dihydroxyphenylacetic acid, homovanillic acid, 3-methoxytyramine, noradrenaline, adrenaline, 3-methoxy-4-hydroxyphenylethylene glycol and 5-hydroxyindoleacetic acid in rat brain dialysates. Samples are obtained in vivo using the microdialysis technique. Microdialysis probes are placed in the brain area to be studied and neurochemicals are collected by perfusion of the probe with modified Ringer's solution. Direct injection of the dialysates allows rapid and reliable results to be obtained.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1992

Biotransformation of L-dopa in striatum and substantia nigra of rats with a unilateral, nigrostriatal lesion: a microdialysis study.

Microdialysis was used to study the biotransformation of L-DOPA in the striatum and substantia nigra of rats with a unilateral 6-hydroxydopamine (6-OHDA) lesion of the substantia nigra. The animals were pretreated with carbidopa (50 mg/kg p.o.) for 5 days. They were anaesthetized, and microdialysis probes were implanted into the intact and denervated striatum and into the intact and lesioned substantia nigra. The biotransformation of L-DOPA (5 mg/kg i.p.) in these regions was investigated. These results were compared with those obtained after administration of a much higher dose of L-DOPA (100 mg/kg i.p.). Changes in extracellular L-DOPA, 3-O-methyldopa (3-OMD), dopamine, dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) were determined by HPLC with electrochemical detection. Although rats with a unilateral nigrostriatal lesion did not show rotational behaviour after 5 mg/kg L-DOPA, DA levels were increased significantly both in the intact and the denervated striatum and in the intact and the lesioned substantia nigra. This increase was most pronounced in the denervated striatum. At 100 mg/kg L-DOPA, the increases in extracellular dopamine in intact and denervated striatum were about twice as high as the increases observed at the lower dose. A similar increase was observed in the intact substantia nigra. However, in the lesioned substantia nigra there was a fourfold increase. L-DOPA, at both doses, was evenly distributed between the brain areas studied and the lesion had no effect on the uptake of the drug at the blood-brain barrier.(ABSTRACT TRUNCATED AT 250 WORDS)

3,4-Dihydroxyphenylacetic Acid↗
PubMed1991

Meningoencephalitis caused by Rickettsia conorii.

Case report of Mediterranean spotted fever in an 18 year old male heroin addict, caused by Rickettsia Conorii. The typical "tache noir" was absent. The patient developed meningoencephalitis within 5 days after onset of the systemic symptoms. Diagnosis was based on serological findings. Treatment with doxycycline led to rapid recovery without sequelae.

Adolescent↗