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Biomedical subjects

H Petit

Publications and source records attributed to H Petit.

At least 91 records · Page 5Linked to original sources
PubMed1994

[Huntington disease. Current state of research].

Huntington's disease is a hereditary disease with autosomal dominant transmission which generally occurs in adults. The gene was discovered in 1983 and the genetic abnormality in March 1993. The most commonly recognized clinical manifestation is choreiform movements although other signs often appear more invalidating to family and friends. Cognitive decline, modifications in behaviour, and sometimes psychiatric disturbances are perceived as the major handicap in everyday life. In this review, emphasis has been placed on late onset forms of the disease. Recent research has focused on morphologic and functional imagery, the neuropathologic stages of selective neurone loss beginning in the striatum, and the role of excitotoxic amino-acids. Certain ethical considerations must be addressed when determining prognosis. Predictive tests and follow-up must be prepared and conducted scrupulously and proposed to voluntary, informed, major subjects at risk. Tests should be performed by a qualified laboratory working on anonymous samples, independent of the clinical team, and should be given to the subject orally by a genetic counsellor. A prenatal test may be requested by parents at risk. The question of treatment, which to date can only offer symptomatic relief, should be re-addressed in light of the recent discovery of the mutation published in March 1993.

Adolescent↗
PubMed1994

Marchiafava-Bignami disease: use of contrast media in CT and MRI.

We report two cases of Marchiafava-Bignami disease studied by CT and MRI. Both patients displayed persistent confusion and a disconnection syndrome but had a favourable outcome. In both cases, CT with intravenous contrast medium revealed enhancement of the corpus callosum in the early stage. MRI showed gadolinium uptake in both the genu and splenium of the corpus callosum in one case, 8 days after the onset. Three weeks after admission, cystic lesions appeared in the corpus callosum on MRI T1-weighted sagittal images in both cases. Contrast medium uptake may be useful in the diagnosis of Marchiafava-Bignami disease.

Adult↗
PubMed1994

Motor memory and the preselection effect in Huntington's and Parkinson's disease.

Patients with Huntington's disease (HD) and Parkinson's disease (PD) show different patterns of preserved and impaired memory performance. This study investigates explicit memory for movements in HD and PD with a linear positioning apparatus using Dick et al.'s procedure (J. Gerontol. 43, 127-135, 1988). In the first experiment, 12 HD patients were compared to 12 matched-controls. HD patients were more impaired than the controls by the delay between criterion and recall movements, whether the delay was filled or unfilled. Switching the limb between criterion and recall movements did not lead to more effects in HD patients and in controls. In the second experiment, 12 non-demented PD patients were compared to matched-controls. PD patients were more impaired than controls when the recall movement was executed with the contralateral hand, but were not more affected by the delay. In both experiments, HD and PD patients, as well as the controls, recalled self-generated preselected movements better than imposed movements. These results suggest the existence of distinct forms of motor memory impairment in some subcortical neurodegenerative diseases.

Adult↗
PubMed1994

[Contribution of morphological imaging in the diagnosis of dementia. I--Alzheimer disease].

In patients with Alzheimer's disease, morphological neuroimaging techniques usually reveal signs of global cerebral atrophy which gradually worsen over time and depends on age and severity of the cognitive decline. Because of the lack of artifacts and of a more appropriate angle, magnetic resonance imaging scans may visualize a prominent atrophy of the medial temporal lobes, including hippocampal structures. Hippocampal atrophy is relatively specific of Alzheimer's disease before 65 and is related to the severity of memory disorders. White matter changes in patients without cerebrovascular risk factors are not more severe in patients with presenile Alzheimer's disease than in age-matched controls. They are, however, more severe in patients with senile onset than in age-matched controls. These findings suggest that white matter changes in patients with senile onset are consistent with a diagnosis of Alzheimer's disease.

Alzheimer Disease↗
PubMed1994

SPECT data in a case of secondary Capgras delusion.

Capgras' delusion (CD) may be secondary to a neurologic lesion, particularly in the right frontal or occipital regions. A 40-year-old woman with multiple sclerosis underwent SPECT during and after an episode of CD. Analysis during delusion showed an uptake defect in the right parietal cortex with an 11% index of asymmetry (normal: < or = 4%). Post-delusion SPECT showed decreased bifrontal and biparietal cortical uptake indices but a normal index of asymmetry. Functional brain imaging may provide clues to the psychopathology of CD.

Adult↗
PubMed1994

Long-term thalamic stimulation in Parkinson's disease: postmortem anatomoclinical study.

Parkinsonian tremor may be suppressed by thalamic stimulation. For an equivalent clinical efficacy, its obvious advantage over micro-thalamotomy is its reversibility. This patient experienced postural tremor at the age of 44 years and akineto-rigid syndrome 8 years later. At the age of 60 years, intrathalamic stimulation was applied over a long-term period of 43 months until death and was efficient on tremor with low stimulation. This case is the first with anatomic verification. The extent of the lesion provoked by the electrode is very small. The location of the stimulation site was in the medio-inferior part of the intermedius complex at the entrance of cerebello-thalamic fibers. The stimulation of the cerebellar afferent axons could be the cause of the clinical effect. The stimulation site corresponds to the thalamic source of the precentral and accessory motor cortex, which correlates with changes observed in our PET study showing a regional cerebral blood flow decrease in cerebellar nuclei and also in precentral and accessory motor cortex. The places and mechanisms of the effects of stimulations and lesions could be different.

Adult↗
PubMed1994

Behavioral effects of trazodone in Alzheimer's disease.

BACKGROUND: Central serotonin depletion may contribute to the anxiety, restlessness, irritability, and affective disturbance seen in a variety of psychiatric conditions, particularly dementia of the Alzheimer's type (DAT) in which brain concentrations of both 5-hydroxytryptamine (5-HT) and its 5-hydroxyindoleacetic acid (5-HIAA) metabolite are reduced. METHOD: Trazodone, a serotonergic antidepressant with alpha 2-adrenergic blocking activity, was administered to 13 patients with DAT in an open 10-week pilot study at a dose of 25 mg t.i.d. Behavioral and affective disturbance was assessed pretreatment and posttreatment using semistructured interview and Jouvent's Depressed Mood and Gottfries-Brane-Steen scales. RESULTS: Irritability, anxiety, restlessness, and affective disturbance were all decreased (p < .05). No side effects were observed. Mean Mini Mental State scores were unaffected by treatment. CONCLUSION: The hypothesis that trazodone corrects behavioral and affective disturbance induced by serotonin depletion in DAT requires confirmation in a double-blind placebo-controlled trial.

Affective Symptoms↗
PubMed1994

Evolution of carotid restenosis after endarterectomy.

Some 176 consecutive carotid endarterectomies performed during 1987 were assessed after 11.5 and 44 months. There were four perioperative deaths. At mean follow-up of 32.5 months the 50% restenosis rate progressed from 9.7% to 11.9%. Of the 168 carotid arteries with a normal patency at discharge, 36 showed progression of stenoses as judged by duplex scanning during the observation period of 44 months. Twenty-nine stenoses were present within 1 year and seven developed between 12 and 44 months. Successive assessments revealed marked differences in the evolution of restenoses which usually depended on the degree of severity reached at the end of the first year: 44% progressed, 28% regressed and only 28% remained stable. The risk of late occlusion in vessels with a < 50% restenosis at 1 year was below 1% and the risk of progressing to a stenosis > 50% was 3.3%. Assessment at 56 months was limited to patients who had a restenotic lesion during the first 44 months. It confirmed that the disease was still unstable with progression in 7% of cases and regression in 10%. This study did not demonstrate any significant restenosis after 20 endarterectomies using the eversion technique compared with an incidence of 13.4% after 156 standard endarterectomies.

Adult↗
PubMed1994

[Unilateral paralysis of the glossopharyngeal, vagus and hypoglossal nerves].

A 32-year-old woman complained of swallowing difficulty after a general seizure. Neurological examination revealed unilateral palsies of the 9th, 10th, and 12th cranial nerves. CT, MRI and internal carotid artery angiogram were normal. Selective catheterization of the external carotid artery and ascending pharyngeal system suggested a cranial nerve ischaemic arterial syndrome. The apparent sparing of the eleventh nerve may be explained by the double vascularization of this nerve. This may also be related to the double innervation of the trapezius and sterno-cleido-mastoid muscles by the 11th nerve and cervical spinal nerves.

Adult↗
PubMed1994

[Subcortical dementia of the Neumann type. Contribution of diagnostic imaging].

A 36 year-old patient presented with a dementia of frontal type, gait disturbances, incontinence and a pseudo-bulbar palsy, which caused death at age 40. Brain biopsy of the frontal lobe showed an extensive deep subcortical gliosis. A high level of GFAP was detected by immunoblotting in the biopsy. Clinical and neuropathological observations are similar to cases described as Neumann Progressive Subcortical Gliosis. Single Photon Emission Computer Tomography showed a bilateral frontotemporal hypoperfusion, and Magnetic Resonance Imaging large periventricular and subcortical hyperintensities in both hemispheres, the brainstem and the cerebellum. The hyperintensities on T2-weighted MR images might be related to the intense gliosis. The contribution of such imaging data to diagnosis must be confirmed by other clinico-pathological cases.

Adult↗
PubMed1993

A positron emission tomography study of patients with acute carbon monoxide poisoning treated by hyperbaric oxygen.

Seven patients with an acute and severe carbon monoxide intoxication were treated with hyperbaric oxygen and underwent a positron emission tomographic examination 2-5 days after the acute event. Although the final clinical outcome was good in all patients, ischaemic changes were observed. Three patients with temporary sequelae after hyperbaric oxygen treatment showed the most severe changes, mainly in striatum and thalamus. Although positron emission tomographic examination cannot predict the final outcome, it can show the regions at risk for development of late complications following carbon monoxide poisoning.

Adult↗
PubMed1993

Unilateral loss of facial flushing and sweating with contralateral anhidrosis: harlequin syndrome or Adie's syndrome?

A 45-year-old woman presented with a 10 year history of asymmetrical facial flushing and sweating after exertion or in hot weather. During these episodes the right side of her face remained dry and white, while the left side normally flushed. Sweating was impaired on the left side in the limbs and trunk. She also had areflexia in the lower limbs and slow pupillary reactions to light and darkness, as seen in Adie's syndrome. The topography of the sweating disorder suggested that the lesion involved the sympathetic pathways at the level of spinal cord. The relationship with the harlequin syndrome and related disorders is discussed.

Adie Syndrome↗