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Biomedical subjects

D Leys

Publications and source records attributed to D Leys.

At least 163 records · Page 9Linked to original sources
PubMed1994

[Treatment of cerebral ischemia in its acute phase and prospectives].

At the acute stage of cerebral ischemia, the "therapeutic window" probably does not last more than 6-12 hours. Despite similar treatments, patients admitted in stroke specialist units are more likely to survive and to have a good functional outcome than patients treated in general wards. In most cases acute arterial hypertension should not be treated. Thrombolytic agents given within 6 hours after onset, are now under evaluation in several clinical trials. There is no scientific evidence to support the use of anti-coagulation as a curative treatment of acute cerebral ischemia; however, clinical trials remain necessary, especially in progressing stroke. Neuroprotective drugs protect neurons against the consequences of hypoxia in animals: most clinical trials with oral nimodipine led to negative results but the meta-analysis suggests that patients receiving nimodipine within 12 hours after stroke onset might have a lower mortality rate and a better functional outcome. Other clinical trials with neuroprotective drugs are currently running: anti-NMDA drugs, chlomethiazol, tirilazad, ganglioside GM 1, etc Most therapeutic agents are now under evaluation. An early admission of patients with acute stroke is required to evaluate therapeutics agents which probably cannot be effective if started more than 6-12 hours after stroke onset.

Acute Disease↗
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

Higher prevalence of atrial septal aneurysms in patients with ischemic stroke of unknown cause.

Atrial septal aneurysms (ASA) are frequent findings on transesophageal echocardiographies. Whether they are more frequent in patients with cerebral ischemia of unknown cause remains unclear. We investigated this question in 154 consecutive patients with an ischemic stroke or transient ischemic attack. The 16 patients with ASA were younger, less likely to have arterial hypertension and more likely to have a patent foramen ovale (PFO) or an unknown cause of stroke, but they did not differ for number and side of infarcts, other demographic data and vascular risk factors. Patients with ASA unassociated to PFO were also more likely to have an unknown cause of stroke. These findings lead to the hypothesis that ASA might be sources of cerebral emboli.

Adolescent↗
PubMed1994

Neuropsychological changes related to unilateral lenticulostriate infarcts.

According to previous studies, focal capsulostriatal lesions may produce aphasia, hemineglect, gestural apraxia, frontal lobe dysfunction, and memory impairment. A few reports of capsulostriate infarcts secondary to involvement of lenticulostriate arteries have confirmed that aphasia and hemineglect may occur whereas gestural apraxia, anosognosia and frontal-lobe symptoms are rare. Most studies used CT scan assessment and did not exclude possible associated lesions. Neuropsychological changes in 11 patients with lenticulostriate infarcts diagnosed by CT scan were prospectively investigated. MRI in five of the 11 patients showed an associated cortical lesion not seen on CT scan. Patients with pure lenticulostriate infarcts on MRI may exhibit aphasia of mild severity whereas Broca's aphasia, hemineglect, gestural apraxia, and anosognosia were only seen in the subgroup with associated cortical lesions. Aphasia in patients with pure lenticulostriate infarcts was characterised by prominent expressive and lexicosemantic task impairments. The results strongly suggest that cortical involvement is critical to the extent and severity of neuropsychological changes in patients with lenticulostriate infarcts.

Adolescent↗
PubMed1994

Borderzone infarct subtypes: preliminary study of the presumed mechanism.

Whether watershed infarcts and internal junctional infarcts have different mechanisms remains unknown. Of 493 consecutive patients with ischemic stroke or transient ischemic attack, 26 had 1 watershed infarct or more (8 anterior and 21 posterior) and 18 had 1 internal junctional infarct or more. Patients with watershed infarcts were more likely to have arterial hypertension [95% confidence intervals of odds ratio (CIOR): 1.04-6.15] and internal carotid artery stenosis > 50% (95% CIOR: 1.03-7.12) than patients without borderzone infarcts. Patients with internal junctional infarcts were more likely to have heart diseases than patients without borderzone infarcts (95% CIOR: 1.46-10.52). This preliminary study suggests that both subtypes of borderzone infarcts probably have different mechanisms.

Adolescent↗
PubMed1994

Evidence for atrophy of the corpus callosum in Alzheimer's disease.

Patients with late-onset Alzheimer's disease (AD) have more white matter changes on magnetic resonance imaging (MRI) than controls. To test the hypothesis that AD patients might have also atrophy of the corpus callosum (CC), we compared the CC thickness on MRI from 20 AD patients and 21 controls. We found a significant reduction in the CC thickness in AD compared with age-matched controls (p < 0.01). We demonstrated that atrophy of the CC depends mainly on the diagnosis of senile dementia of the Alzheimer type and at a lower degree on the diagnosis of presenile AD but neither on age nor on ventricle enlargement. This result suggests that beside the greater severity of white matter involvement in late-onset AD, atrophy of the CC may also be present.

Aged↗
PubMed1994

Anterior choroidal artery territory infarcts. Study of presumed mechanisms.

BACKGROUND AND PURPOSE: A previous study suggested that occlusive diseases of small penetrating arteries account for most anterior choroidal artery (AChA) territory infarcts, but half of the patients did not have an echocardiogram. Cases of AChA territory infarcts associated with internal carotid artery stenosis or atrial fibrillation suggest that this hypothesis may be wrong. The aim of this study was to determine the mechanism of 16 nonselected consecutive AChA territory infarcts. METHODS: The study population consisted of 8 men and 8 women aged 17 to 89 years. They underwent a computed tomographic scan at the acute stage, Doppler ultrasonography and B-mode echotomography of the cervical arteries, bidimensional transthoracic echocardiography, and cerebral magnetic resonance imaging, replaced by a second computed tomographic scan in 3 patients. Ten patients underwent cerebral angiography. We defined the presumed cause of stroke according to the criteria used in the trial of Org 10172 in acute stroke treatment. RESULTS: The presumed cause of stroke was definite cardio-embolism in 4 patients (atrial fibrillation in 2, paradoxical embolism in 1, and left ventricular akinesia in 1); definite large-vessel atherosclerosis in 2; dissection of the internal carotid artery in 2; and definite small-vessel occlusion in 1. Seven patients had a negative diagnostic workup. Six patients had no risk factors for small-vessel occlusion. The AChA was not visible on angiography in 4 patients. One patient had two arterial cutoffs, suggestive of emboli in other cerebral arteries. CONCLUSIONS: This study suggests that AChA territory infarcts are rarely related to small-vessel occlusion and therefore require a complete diagnostic workup.

Adolescent↗
PubMed1994

[Lingual motility in unilateral hemispheric vascular complications. Study of the cortico-hypoglossal afferences].

Lingual motricity was prospectively studied in 32 consecutive stroke patients with hemiparesis or hemiplegia involving the face. We excluded patients with vertebrobasilar infarcts, controlateral stroke, arteriovenous malformations, internal carotid artery dissection, severe aphasia or severe bucco-lingual apraxia. The study population consisted of 18 males and 14 females with a mean age of 64.2 years. Seventeen patients had a lesion located in the right hemisphere and 15 in the left one. The lesion was of ischemic origin in 19 patients and hemorrhagic in 13. Lingual motricity was studied at rest and at protraction. We recorded whether the following abnormalities were present: lingual deviation, limitation of protraction or lateral movements, atrophy, hypotonia and fasciculations. Sixteen patients had a deviation of the tongue at protraction. The other abnormalities were deviation of the tongue at rest, limitation of lateral movements at protraction, unilateral lingual hypotonia and limited protrusion. Of 16 patients with deviation of the tongue at protraction, 10 had no deviation at rest. Of the 6 remainders, 2 had deviation of the tongue towards the opposite side, at rest, and 4 towards the same side. Most patients with deviation of the tongue at protraction, had a lesion of the posterior limb of the internal capsule and of the posterior part of the lenticular nucleus. Most patients without lingual deviation, had a lesion of the capsule-lenticular region and of the superior portion of the internal capsule, just under the corona radiata.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Regional cerebral blood flow imaging: a quantitative comparison of 99mTc-bicisate with 133Xe using single photon emission computed tomography.

The aim of this study was to compare 99mTc-bicisate with 133Xe inhalation in regional CBF (rCBF) imaging. Five healthy volunteers and five patients were imaged with both techniques. Regional standardized values (SVs) of 99mTc-bicisate, uptake indexes (UIs), and asymmetry indexes (AIs) were compared quantitatively with, respectively, rCBF, flow indexes (FIs), and AIs. Areas with highest rCBF (sylvian and thalamic areas) appeared to be underestimated with 99mTc-bicisate, but significant correlations were found between SV and rCBF (n = 140, r = 0.468, p < 0.01) and for the 10 subjects between UI and FI and between AIs (p < 0.0001). There are therefore distinct regional differences in the cerebral distinction of 99mTc-bicisate and CBF, particularly in the thalamus and the temporal cortex. It is probable but not yet proved that an underestimation of high flow rates occurs with bicisate.

Adolescent↗
PubMed1993

[Results of clinical trials evaluating the surgery of carotid stenoses].

The usefulness of carotid endarterectomy remained unsettled until 1991, although it was one of the most widespread surgical interventions. Its indications are now being scientifically established by means of perspective and randomized clinical trials comparing endarterectomy to medical therapy in patients with internal carotid artery atherosclerosis. The results of 2 trials (CASANOVA, VACS#167) performed in asymptomatic patients suggest that there is no evidence that carotid endarterectomy might be of benefit in such patients; however both studies had serious methodological problems that will probably be resolved by a large on-going study (ACAS). The results of 3 trials performed in patients with recent transient ischemic attacks or stroke in the internal carotid artery territory suggest that: (1) carotid endarterectomy is of benefit in patients with a degree of stenosis higher than 70%; (2) carotid endarterectomy is not of benefit in patients with a degree of stenosis smaller than 30%; (3) the best therapeutic strategy remains unsettled in patients with a 30-70% degree of stenosis and in patients examined more than 6 months after neurological deficits.

Carotid Artery, Internal↗
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

A semiquantative rating scale for the assessment of signal hyperintensities on magnetic resonance imaging.

Differences in grading signal hyperintensities on magnetic resonance imaging may explain earlier reported conflicting results in studies of normal aging and dementia. We designed a new rating scale in which periventricular and white matter signal hyperintensities as well as basal ganglia and infratentorial signal hyperintensities are rated separately in a semiquantative way. In this study we compared the inter- and intra-observer agreements of this scale to the widely used rating scale of Fazekas. We confirmed the poor to reasonable intra- and inter-observer agreements of the Fazekas scale. The new scale, although more elaborate, provided good agreements with respect to the white matter, basal ganglia and infratentorial signal hyperintensities. In rating periventricular hyperintensities this scale yielded no advantage. It is concluded that this scale may be of use in studies especially focussing on deep white matter pathology on MRI, because it provides more detailed information, with good intra- and inter-observer reliability.

Aged↗
PubMed1993

Pure sensory stroke revealing a complex malformation of extra- and intracranial cerebral arteries.

Pure sensory strokes (PSS) are usually due to thalamic lacunar infarcts. We report a case of PSS in a 34-year-old female suffering from migraine who complained of sudden isolated left-sided paresthesia involving face, upper and lower limbs. We found a complex vascular abnormality associating internal carotid artery occlusion, posterior cerebral artery agenesia, aneurysm at the posterior face of the carotid siphon and angiomatous rete at the top of the basilar artery. The acquired origin of the carotid artery occlusion by possible neonatal dissection is probable since this patient has a permeable carotid canal on CT scan.

Adult↗
PubMed1993

Silent infarcts in patients with ischemic stroke are related to age and size of the left atrium.

BACKGROUND AND PURPOSE: Possible specific risk factors for silent infarcts remain unknown. The aim of this study was to investigate whether risk factors for silent infarcts differ from those for symptomatic infarcts in stroke patients. METHODS: Silent infarcts were defined as asymptomatic infarcts detected on computed tomographic scan in patients free of history of stroke and unrelated to the symptoms and signs of the index stroke. Of 595 consecutive patients with stroke or transient ischemic attacks, 116 (19%) had at least one silent infarct on the first computed tomographic scan performed within 24 hours after onset. They were compared with the 479 remaining patients for cerebrovascular risk factors and for presumed mechanism of stroke by means of the odds ratio method. A discriminant analysis was then performed in the subgroup of 216 patients with ischemic stroke who underwent an exhaustive cardiac and vascular workup. RESULTS: One hundred forty-one silent infarcts (99% confidence interval [CI], 29% to 41%) and 265 symptomatic infarcts (99% CI, 59% to 71%) were subcortical infarcts smaller than 15 mm. Univariate analysis showed that patients with silent infarcts were more likely to be older than 65 years (odds ratio [99% CI], 1.11 to 3.49) and to have left atrial enlargement on echocardiogram (odds ratio [99% CI], 1.02 to 26.70) and leukoaraiosis (odds ratio [99% CI], 1.39 to 4.21). Discriminant analysis found only two independent risk factors for silent infarcts: left atrial enlargement (P = .007) and age older than 65 years (P = .03); leukoaraiosis was not found to be an independent risk factor (P = .86). CONCLUSIONS: Age and left atrial enlargement are the main risk factors for silent infarcts in patients with ischemic stroke or transient ischemic attacks.

Adolescent↗
PubMed1993

[Natural history and spontaneous prognosis of cerebral arteriovenous malformations].

Eight large series of patients presenting with untreated cerebral arterio-venous malformations (A.V.M.) were reviewed. Data were gathered on 1134 patients who were followed for 20 years or more. The risk of rupture and the rate of other complications were estimated, in relation with other factors like age of patient, size of A.V.M., or hemodynamic stresses. The prevalence of A.V.M. at autopsy is 14 per 10,000 population. Fifty percent of A.V.M.s remain asymptomatic during the whole patient's life. The risk of hemorrhage from rupture of an A.V.M. is 2% per year and per patient. Hemorrhage is more frequent from small-sized A.V.M.s, mostly under certain hemodynamic factors. The risk of hemorrhage is also higher in children between 5 and 10 years of age, and in women to the end of pregnancy. The incidence of seizures and neurological impairment is approximately 1% per year and per patient, and these symptoms mostly occur in elder patients with large A.V.M.s. If the A.V.M. has not been revealed by hemorrhage, the risk of rupture is 1% per year and per patient. The incidence of complications from fortuitously diagnosed A.V.M.s seems very low, and even nil in some series. The risks of therapeutic procedures could not be determined, but in some A.V.M.s, the association of different therapeutic means seems mor advisable than isolated therapy. The analysis of natural history of A.V.M.s is desirable to provide a better information to the patient, and to define the limits of therapeutic indications.

Age Factors↗