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B Guiraud-Chaumeil

Publications and source records attributed to B Guiraud-Chaumeil.

13 recordsLinked to original sources
PubMed1992

[Is there any desensitization of presynaptic alpha 2-adrenergic receptors in hypertension? Experimental and clinical studies].

Several authors have discussed an alteration of adrenergic receptivity in arterial hypertension. De Champlain (Hypertension 1990; 8: S77-S85) suggested that postsynaptic alpha 1-adrenergic functions became dominant while beta-adrenergic functions are attenuated in arterial hypertension. However, the status of presynaptic alpha 2-adrenoceptors remains unknown. The present study investigates presynaptic alpha 2-adrenoceptors in hypertension through the measurement of plasma levels of noradrenaline after administration of yohimbine, an alpha 2-adrenoceptor antagonist, in essential hypertension. Yohimbine (0.2 mg/kg per os) induced a 73% increase of plasma levels of noradrenaline in hypertensive patients (n = 12) and a 178% one in normotensive subjects (n = 6, p < 0.05). A similar significant difference was found in experimental neurogenic hypertension observed in awake dogs 3 weeks after sinoaortic denervation: the increase in plasma concentrations of noradrenaline after yohimbine (0.5 mg/kg i.v.) was +279% in hypertensive versus +642% in normotensive dogs (p < 0.05). The results show that the magnitude of the yohimbine-induced sympathetic activation is lower in hypertensives than in normotensives. They suggest the existence of a presynaptic alpha 2-adrenoceptor desensitization in arterial hypertension. The abnormality of this presynaptic inhibitory mechanism can increase the sympathetic tone and help to develop and maintain arterial hypertension.

Adrenergic alpha-Antagonists↗
PubMed1989

SPECT study of cerebral blood flow reactivity after acetazolamide in patients with transient ischemic attacks.

We investigated 15 patients with one or more transient ischemic attacks (TIAs) in the internal carotid artery territory within the month following the most recent TIA. Cerebral blood flow (CBF) was measured by single-photon emission computed tomography, using intravenous xenon-133 before and after injection of 1 g acetazolamide. Six patients had severe carotid stenosis or occlusion; the other nine patients had no significant carotid lesions. Twenty age-matched volunteers free of neurologic symptoms or history were used as controls. Mean CBF in the sylvian region was not significantly different between patients and controls. Seven patients exhibited a focal hypoperfusion at rest in the symptomatic hemisphere, and their hypoperfused areas were hyporeactive after administration of acetazolamide. Seven other patients exhibited hyporeactive areas after acetazolamide administration while their CBF tomograms at rest were normal. Thus, CBF abnormalities were detected in 14 of the 15 patients. Our findings suggest that CBF measured early after acetazolamide administration could be useful to confirm the clinical diagnosis of TIA. In the nine patients with no significant lesion of the internal carotid artery, the areas of hypoperfusion were small and were probably related to the focal ischemic event. In the six patients with severe lesions of the internal carotid artery, abnormalities were of variable size and intensity but were often large and pronounced. The discrepancy between these two subgroups of patients could be ascribed to the hemodynamic influence of the internal carotid artery lesions. Moreover, our findings may provide some insight into the pathophysiology of TIAs.

Acetazolamide↗
PubMed1986

[Role of the thalamus in subcortical aphasias].

27 cases of patients who presented language disorders of aphasic nature consecutive to a strictly subcortical lesion of vascular origin are reported. From a topographic point of view, the population is divided into 3 groups: thalamic lesions (15 cases), striatal lesions (9 cases), isolated lesions of the white matter (3 cases). The results of the neurolinguistic analysis of the aphasia show a great symptomatological variety. Nevertheless, in spite of this apparent diversity, certain semiologic elements appear to be common to all of the observed linguistic profiles, no matter where the lesion is: hypophonia, non fluent speech, verbal paraphasias, normal repetition, comprehension generally good. A discussion is proposed as to the specific part which certain structures, notably the thalamus, might play in the origin of these various disturbances.

Aphasia↗
PubMed1986

[Analysis of the cerebrospinal fluid by isoelectrofocusing on agarose in multiple sclerosis].

Intrathecal synthesis of immunoglobulins can be proved by means of two methods: quantitatively by immunoglobulins titration in CSF, the results expressed with several ratios; qualitatively by demonstration of oligoclonal distribution of gammaglobulins. IEF is the most sensitive of the qualitative methods. From a technical point of view Agarose Isoelectrofocusing seems to be a better method than polyacrylamide isoelectrofocusing and permits, when the interpretation is difficult, immunofixation into the gel. The authors report the results of a comparative study between the evaluation of the IgG Index and agarose isoelectrofocusing of 281 CSF divided into 113 CSF from patients with Multiple Sclerosis (MS) and 168 CSF from patients with other neurological diseases (OND). Sensitivity of IEF was higher than IgG index to prove intrathecal IgG synthesis: in the group of patients with MS, 91 p. 100 of CSF were abnormal instead of 72 p. 100 of IgG Index. In the group of patients with OND, abnormalities in IEF were low (5 p. 100) but the number of inflammatory diseases was poor. These results were similar with the findings of many authors using the same methods. In our opinion, IEF is the best technique which a specialized laboratory can use in routine to prove an immunoglobulin intrathecal synthesis.

Central Nervous System↗
PubMed1985

Measurement of plasma levels of clomipramine in the treatment of chronic pain.

The analgesic effect of clomipramine and the possible relationships between the antalgic action and the plasma levels of this tricyclic drug have been studied in 30 patients with chronic pain induced by nervous lesions determining a deafferentation. Twenty of 30 patients treated with clomipramine reported a significant improvement (up to 50%) observed as soon as the 4th day, with few side effects. The pharmacokinetic analysis shows the existence (r = 0.358; p less than 0.001) of a relationship between analgesia and plasma levels of clomipramine for each individual patient. This study also indicates a "therapeutic window" of plasma levels between 20 and 85 ng/ml. These results permit discussion of measurement of plasma levels of clomipramine in the treatment of chronic pain.

Chronic Disease↗
PubMed1984

[Subcortical aphasia. Neruolinguistic and x-ray computed tomography studies of 25 cases].

Twenty five cases of subcortical aphasia of vascular origin (15 haemorrhagic, 10 ischaemic), have been studied in detail by means of neurolinguistic and brain-scanning approaches. The neurolinguistic investigation allowed three groups to be distinguished. Group 1 comprised 4 cases of dysarthria. Group 2 was made up of 9 classical syndromes of aphasia: 2 global aphasias, 3 Broca's aphasias, 3 cases of Wernicke's aphasia and 1 case of conduction aphasia. Group 3 consisted in 12 unusual aphasic syndromes, i.e. 2 mixed aphasias and 10 cases which did not correspond with any traditional semiological description and are spoken of as "dissident" (or anomalous) cases. The CT scan results revealed a wide range of focal lesions for the same clinical syndrome; the 10 "dissident" cases were, in particular, associated with a large variety of lesions. After a discussion of the anatomical limits of the subcortical lesions, 2 points emerge: 1) in the current state of technological experience no anatomo-clinical correlation can be drawn as regards language-deficiencies of subcortical origin. 2) in almost half the cases a "unique" syndrome of aphasia has been observed and described, which at first might suggest the diagnosis of a subcortical lesion.

Adult↗