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Biomedical subjects

A Rascol

Publications and source records attributed to A Rascol.

At least 37 records · Page 2Linked to original sources
PubMed1992

Supplementary and primary sensory motor area activity in Parkinson's disease. Regional cerebral blood flow changes during finger movements and effects of apomorphine.

We have measured with single-photon emission tomography the regional cerebral blood flow changes that occurred in the supplementary motor areas and in the primary sensory motor areas during sequential finger-to-thumb opposition movements of the right hand in seven akinetic patients with Parkinson's disease and in nine normal volunteers. Parkinsonian patients were studied before ("off" condition) and after a subcutaneous injection of apomorphine hydrochloride which was able to switch them "on" (on condition). In normal volunteers and parkinsonian patients in the on condition, regional cerebral blood flow significantly increased in the supplementary motor areas and in the contralateral primary sensory motor cortex but not in the ipsilateral primary sensory motor cortex. On the contrary, no significant regional cerebral blood flow change was observed in these areas in parkinsonian patients in the off condition. These results support the hypothesis that a functional cortical motor area deafferentation is involved in the pathophysiological makeup of akinesia and that this abnormality is reversed by dopaminergic drugs.

Aged↗
PubMed1992

Effects of a selective partial D1 agonist, CY 208-243, in de novo patients with Parkinson disease.

A selective dopamine D1-receptor agonist, CY 208-243, was administered to 23 de novo patients who had had Parkinson disease (PD) for less than or equal to 3 months. The drug was first used as monotherapy and then in some patients in combination with a dopamine D2-receptor agonist, bromocriptine. Results showed that CY 208-243 exerted a mild antiparkinsonian action, and tremor was the main symptom that consistently improved. The addition of bromocriptine less than or equal to 15 mg to CY 208-243 did not result in additional improvement, but this might be due to the short duration of treatment and the low doses of bromocriptine. The study was prematurely discontinued for safety reasons. We conclude that D1-receptor stimulation may result in improvement of motor disability in PD.

Adult↗
PubMed1992

Parkinson's disease and weight loss: a study with anthropometric and nutritional assessment.

In order to investigate a putative weight loss in patients with Parkinson's disease, an anthropometric and biochemical study was undertaken. We compared body weight and indexes of fat [body mass index (BMI), tricipital skinfold] and lean [midarm muscle area (MMA), calf circumference] mass in men and women suffering from idiopathic Parkinson's disease with normal controls. We found that women suffering from Parkinson's disease exhibited a significant weight loss (-8.5%) and decreased calf circumference when compared with controls. A decrease (-4.3%) in total body weight was also found in men with Parkinson's disease but the difference did not reach the level of significance. Protein biochemical markers of nutritional status (albumin, prealbumin, retinol binding protein, transferrin) were normal in Parkinson's disease patients. The present study demonstrates the occurrence of weight loss in a large population of patients with Parkinson's disease. The putative mechanisms involved in the weight loss are discussed.

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PubMed1992

Ambulatory blood pressure in patients with Parkinson's disease without and with orthostatic hypotension.

Non-invasive ambulatory recordings of blood pressure and heart rate were performed using a Spacelabs device during day and night periods in patients with Parkinson's disease with (n = 19) or without orthostatic hypotension (n = 19). In patients with orthostatic hypotension, the average systolic and diastolic blood pressure during the night (137 +/- 5/80 +/- 3 mmHg) was higher (p less than 0.05) than during the day period (121 +/- 3/76 +/- 2 mmHg). In patients without orthostatic hypotension, a decrease in blood pressure was recorded during the nocturnal period. In patients with orthostatic hypotension, the blood pressure variability was higher (p less than 0.05) during the day (systolic: 14.6 +/- 1.3%; diastolic: 16.5 +/- 1.0%) than during the night (systolic: 9.1 +/- 0.8%; diastolic: 10.8 +/- 1.1%). The blood pressure load (percentage of values above 140/90 mmHg) during the night was significantly higher than during the day for both systolic (41.2 +/- 8.1 vs. 19.6 +/- 4.7%) and diastolic blood pressure (24.9 +/- 6.9 vs. 16.3 +/- 4.9%). There was a decrease in heart rate in both groups during the night. A fall of 25 mmHg or more in systolic blood pressure after meals occurred in ten patients with orthostatic hypotension and in one patient without orthostatic hypotension. These results indicate that orthostatic hypotension in Parkinson's disease is associated with specific modifications of ambulatory blood pressure including loss of circadian rhythm of blood pressure, increased diurnal blood pressure variability and post-prandial hypotension.

Aged↗
PubMed1992

Cerebral blood flow correlates of word monitoring in sentences: influence of semantic incoherence. A spect study in normals.

The aim of this study was to assess the cerebral blood flow (CBF) changes induced by the semantic incoherence of sentences whose words were to be monitored by the subjects. According to Marslen-Wilson and Tyler, word processing would be parallel (global) in semantically coherent sentences, and serial (local) in semantically incoherent ones. We hypothesized that, in comparison with the parallel mode, the serial mode of word processing would result in a preponderant activation of the frontal lobes and/or of the left hemisphere, hence in a flow increase in these regions. In addition, one could assume that the increase in task complexity resulting from the breaking of semantic coherence would reinforce the functional links between hemispheres. Furthermore, as interactions between the processing of semantically coherent vs incoherent of verbal materials and the processing of imageable vs non-imageable stimuli was recently suspected, we designed a study combining coherent vs incoherent sentences and imageable vs non-imageable words. The results we obtained in 12 normal volunteers by measuring regional cerebral blood flow by SPECT and IV injection of Xenon 133 during the four experimental conditions, did not allow us to firmly establish our hypotheses. Indeed, we failed to demonstrate any significant CBF changes across conditions and there was no interaction between coherent vs incoherent and imageable vs non-imageable conditions. However, the analysis of the inter-regional correlations pointed to an increase in the functional links between the hemispheres in the incoherent conditions, whatever the imageability.

Adult↗
PubMed1992

The anatomy of phonological and semantic processing in normal subjects.

We assessed brain activation of nine normal right-handed volunteers in a positron emission tomography study designed to differentiate the functional anatomy of the two major components of auditory comprehension of language, namely phonological versus lexico-semantic processing. The activation paradigm included three tasks. In the reference task, subjects were asked to detect rising pitch within a series of pure tones. In the phonological task, they had to monitor the sequential phonemic organization of non-words. In the lexico-semantic task, they monitored concrete nouns according to semantic criteria. We found highly significant and different patterns of activation. Phonological processing was associated with activation in the left superior temporal gyrus (mainly Wernicke's area) and, to a lesser extent, in Broca's area and in the right superior temporal regions. Lexico-semantic processing was associated with activity in the left middle and inferior temporal gyri, the left inferior parietal region and the left superior prefrontal region, in addition to the superior temporal regions. A comparison of the pattern of activation obtained with the lexico-semantic task to that obtained with the phonological task was made in order to account for the contribution of lower stage components to semantic processing. No difference in activation was found in Broca's area and superior temporal areas which suggests that these areas are activated by the phonological component of both tasks, but activation was noted in the temporal, parietal and frontal multi-modal association areas. These constitute parts of a large network that represent the specific anatomic substrate of the lexico-semantic processing of language.

Adult↗
PubMed1991

[Cerebral imaging and aphasia].

In the field of aphasiology, cerebral imaging has greatly helped in modifying our concepts concerning the physiopathological mechanisms underlying language. Morphological imaging, and particularly computerized tomography (CT), has provided a critical appraisal of established doctrines as well as evidence that subcortical structures participate in language. A more dynamic and evolutive approach of brain organization for language has been introduced by CT and emission imaging techniques which have shown on one side the existence of age-related modifications in the language area, and on the other side the possibility of recovery by activation of structures other than those classically involved. Finally, magnetic resonance imaging has recently revived interest in the study of strict anatomico-clinical correlations.

Adult↗
PubMed1991

Pharmacological evidence of alpha 1- and alpha 2-adrenergic supersensitivity in orthostatic hypotension due to spinal cord injury: a case report.

Sympathetic efferent pathways and alpha-adrenergic receptivity were investigated in one patient with spinal cord transection (D1 level) and orthostatic hypotension. The lack of increase in catecholamine plasma levels during orthostasis and the paradoxical pressor effect of clonidine (2 micrograms/kg orally) suggested complete interruption of efferent sympathetic pathways. The pressor response to exogenous noradrenaline was significantly higher in the patient than in 6 normal controls (0.09 vs 0.72 micrograms.kg-1), indicating supersensitivity of vascular alpha-adrenoceptors. The platelet alpha 2-adrenergic receptor number, measured with [3H]yohimbine, was 507 in the patient vs 178 fmol.mg-1 protein in controls. The increase in systolic blood pressure induced by 10 mg midodrine, a specific alpha 1-agonist, was significantly higher in the patient (delta = 56 mm Hg) than in controls (delta = 15 mm Hg). The results indicate that in the patient there was alpha-adrenergic supersensitivity both of alpha 1- and alpha 2-adrenoceptors. This led to successfully oral treatment of the orthostatic hypotension with clonidine 150 micrograms bd and midodrine 10 mg bd.

Blood Pressure↗
PubMed1991

Effects of levodopa and bromocriptine on blood pressure and plasma catecholamines in parkinsonians.

Blood pressure (BP), heart rate (HR), plasma noradrenaline (NA), and adrenaline (A) levels in the lying and standing position were compared in patients with Parkinson's disease (PD) and control subjects. Three groups of PD patients (stage 2 and 3) were investigated: six patients deprived of antiparkinsonian drugs from 48 h, seven levodopa + benserazide-treated patients, and seven bromocriptine-treated patients. BP, HR, NA, and A were similar at rest and in the standing position in controls and in PD patients deprived of antiparkinsonian drugs from 48 h. Chronic treatment with levodopa (+ benserazide) failed to modify BP, HR, NA, and A. Bromocriptine decreased BP, HR, and NA (but not A) at rest. In PD patients treated with levodopa (+ benserazide) or bromocriptine alone, the rise in NA (but not A) elicited by standing up was reduced. These results indicate that (a) stages 2 to 3 of Parkinson's disease are not accompanied by major changes in autonomic cardiovascular function and (b) dopaminergic drugs blunted the sympathetic response to standing up.

Aged↗
PubMed1991

Sublingual apomorphine in Parkinson's disease: a clinical and pharmacokinetic study.

The clinical response and the pharmacokinetic parameters of 3 mg subcutaneous (SC) and 30 mg sublingual (SL) apomorphine were compared in nine patients with Parkinson's disease. The magnitude of the motor responses (evaluated by tapping and walking tests and the Webster scale) was similar for SC and SL apomorphine. However, the onset to action was delayed after SL when compared with SC apomorphine. No significant difference was found in bioavailability (area under the curve: AUC) or peak plasma concentration (Cmax) between SC and SL apomorphine, whereas time to peak plasma concentration (Tmax) was shorter after SC apomorphine. Eight other patients were treated for a mean time of 4 months with SL apomorphine with a significant reduction in daily "off" hours. However, four of these eight patients developed stomatitis after some weeks of treatment. These results indicated that (a) pharmacokinetics parallel the clinical response to SL apomorphine, (b) SL apomorphine can reduce severe off periods in parkinsonian patients when used chronically, and (c) its long-term use is limited by a severe side effect (stomatitis).

Administration, Sublingual↗
PubMed1991

Subcutaneous apomorphine increases regional cerebral blood flow in parkinsonian patients via peripheral mechanisms.

1. We have measured regional cerebral blood flow (rCBF) and motor function before and after the subcutaneous (s.c.) injection of apomorphine in parkinsonian patients deprived of their usual treatment for at least 48 h. 2. Nineteen patients, pretreated with domperidone (20 mg three times daily for 48 h), received a mean dose of 5.8 mg s.c. apomorphine. All patients switched 'on'. The mean motor score was significantly improved (-65%, P less than 0.01) but no significant change in rCBF was observed. 3. Seven other patients, not pretreated with domperidone, received a lower dose (0.3 mg) of s.c. apomorphine. No change in motor score was observed while the mean rCBF significantly increased (+12%, P less than 0.05). 4. We conclude that s.c. apomorphine increases rCBF in parkinsonian patients. This effect is independent of the central therapeutic effects of the drug. It is mediated by the stimulation of dopaminergic receptors of the cerebral vessels. These receptors are located outside the cerebral blood brain barrier and can be considered as 'peripheral' ones.

Aged↗
PubMed1991

Square wave jerks in parkinsonian syndromes.

The frequency of square wave jerks (SWJ) was compared in eight patients with progressive supranuclear palsy (PSP), 25 patients with multiple system atrophy or Parkinson's disease plus (MSA/PP), 85 patients with idiopathic Parkinson's disease (PD) and 20 age-matched normal volunteers. In the control group, the mean (SD) SWJ frequency (SWJ larger than 1 degree amplitude) was 2.3 (2.4)/min. Abnormal ocular fixation (SWJ frequency greater than 10/min) was observed in a large proportion of PSP patients (7/8) and of MSA/PP patients (16/25) but in few PD patients (13/85). In the group of PD patients with abnormal ocular fixation, freezing of gait, falls and instability were more severe than in the group of PD patients with normal fixation. The study of ocular fixation may help to differentiate PD clinically from other Parkinsonian syndromes. SWJ are probably not related to the central degeneration of the dopaminergic nigrostriatal pathway observed in PD.

Aged↗
PubMed1991

Cognition and cerebral blood flow in lateralised parkinsonism: lack of functional lateral asymmetries.

Cognitive and cerebral blood flow (CBF) lateral asymmetries have been quantified in 23 right handed patients with lateralised idiopathic Parkinson's disease. Thirteen patients who had predominant right-sided symptoms (RPD) were compared with ten who had predominant left-sided symptoms (LPD). The patient subgroups were matched for age, education, duration of illness, disease severity and medication. Normalised asymmetries scores were calculated from the data obtained with a test battery and SPECT. No correlation was found between laterality of motor Parkinsonian symptoms and cognitive or haemodynamic asymmetry scores.

Aged↗
PubMed1991

Quantitative assessment of cerebral blood volume by single-photon emission computed tomography.

We implemented a technique for measuring regional cerebral blood volume using single-photon emission computed tomography and in vivo technetium-99m-labeled red blood cells and then evaluated it in nine normal human volunteers (controls) and seven patients with bilateral occlusion or severe stenosis of the internal carotid artery. We also measured regional cerebral blood flow using single-photon emission computed tomography and intravenous xenon-133 in the same subjects. We studied regional cerebral blood flow, regional cerebral blood volume, and their ratio before and after the intravenous injection of 1 g acetazolamide. Mean +/- SD baseline regional cerebral blood volume was higher in the patients than in the controls (4.1 +/- 0.6 versus 3.2 +/- 0.3 ml/100 g, p less than 0.01), and mean +/- SD baseline regional cerebral blood flow was lower in the patients than in the controls (40.5 +/- 11 versus 55.6 +/- 11 ml/100 g/min, p less than 0.05). Acetazolamide induced similar mean +/- SD increases in regional cerebral blood volume in both the controls and the patients (0.3 +/- 0.1 and 0.3 +/- 0.2 ml/100 g), while the mean +/- SD regional cerebral blood flow reactivity was significantly less in the patients than in the controls (12.6 +/- 7.6 versus 24.5 +/- 9.6 ml/100 g/min, p less than 0.05). Our study shows that single-photon emission computed tomography can provide quantitative estimates of both regional cerebral blood volume and regional cerebral blood flow in humans.

Acetazolamide↗
PubMed1991

[Late myopathies located at the spinal muscles: a cause of acquired lumbar kyphosis in adults].

A primary myopathy limited to the spinal muscles and of late onset was suspected in 14 patients with a mean age of 66. These patients had an anterior inflection of the trunk and were unable to rotate the lumbar spine on the pelvis. This incurvation of the trunk, starting at around age 60, was reducible in a horizontal position and increased with tiredness. The CT scan appearance of the spinal muscles of these patients was hypodense and heterogeneous, different from the atrophy found in the elderly with lumbar osteoarthrosis, comparable with the lesions described in primary myopathies. Histologically, lesions of fibro-adiposis were major, accompanied by mitochondrial abnormalities. The frequent existence of a family history would be in favour of a genetically transmitted condition.

Aged↗
PubMed1991

[Cerebral blood volume, endarterectomy and SPECT].

Cerebral blood flow and cerebral blood volume were measured and quantified using single photon emission computed tomography before and after unilateral endarterectomy in 3 patients with bilateral severe lesions of the internal carotid artery. These parameters were measured using an intravenous injection of 133 Xenon and 99m Technetium respectively. Before endarterectomy cerebral blood volume was high in all patients suggesting a focal vasodilatation in response to a reduced cerebral perfusion pressure. After endarterectomy a decrease of cerebral blood volume and an increase of cerebral blood flow were observed. These preliminary results confirm that the hemodynamic adaptative mechanisms secondary to carotid occlusion are reversible when the stenosis is removed and demonstrate that these changes can be accurately measured using single photon emission computed tomography. Positron emission tomography was previously considered to be the only method able to quantify cerebral blood volume in man. Single photon emission computed tomography can also be considered a reliable technique to measure both cerebral blood flow and cerebral blood volume. This technique can then be used to assess individual cerebral vascular adaptative states and to evaluate the influence of cerebral hemodynamic changes on stroke occurrence in large longitudinal studies.

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