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Biomedical subjects

Jean-Louis Mas

Publications and source records attributed to Jean-Louis Mas.

31 records · Page 2Linked to original sources
PubMed2004

[Indications for revascularisation of a carotid stenosis].

TO PREVENT ISCHEMIC STROKE: Three types of measures should be taken: correction of the vascular risk factors, administration of antithrombotic agents and carotid revascularisation in patients selected on the basis of clinical and imaging criteria. CAROTID REVASCULARISATION MEASURES: The optimal indications are carotid surgery for severe symptomatic stenosis, while the benefits are marginal in severe asymptomatic stenosis and in moderate symptomatic stenosis. INDICATIONS FOR PERCUTANEOUS ANGIOPLASTY WITH PLACING OF AN ENDOPROSTHESIS: Angioplasty with endoprosthesis, a possible alternative to surgery, must be restricted to symptomatic stenosis either in randomised studies or in severe stenosis in patients in whom surgery is technically contraindicated.

Angioplasty, Balloon↗
PubMed2004

Increased stiffness of the carotid wall material in patients with spontaneous cervical artery dissection.

BACKGROUND AND PURPOSE: The cause of spontaneous cervical artery dissection (sCAD) is largely unknown. An underlying connective tissue disorder has often been postulated, but arterial mechanical properties have rarely been studied. The study aim was to determine the elastic properties of a cervical artery, the common carotid artery, and a distal muscular artery, the radial artery in sCAD patients. METHODS: We studied 32 patients with previous sCAD (median delay: 2.2 years) and 32 control subjects with similar age and blood pressure. Internal diameter, intima-media thickness, distensibility, and Young's elastic modulus were determined at the site of the right and left common carotid arteries and the radial artery using noninvasive high-resolution echotracking systems. RESULTS: In patients with previous sCAD, cross-sectional distensibility and compliance of the affected carotid artery did not differ from those of the contralateral carotid artery. Young's elastic modulus (ie, the stiffness of the wall material) was 58% higher (0.44+/-0.32 versus 0.28+/-0.15 kPa.10(3), P<0.001) and circumferential wall stress was 14% higher (56+/-12 versus 49+/-12 kPa, P<0.001) in sCAD patients than in controls. The highest tertile of common carotid artery Young's elastic modulus was associated with an 8-fold higher risk of sCAD. Aortic stiffness, assessed from the carotid-femoral pulse wave velocity, and radial artery parameters did not differ between sCAD and controls. CONCLUSIONS: Carotid arteries, but not aorta and radial artery, displayed abnormal elastic properties in sCAD patients. Higher stiffness of carotid wall material and circumferential wall stress could increase the risk of dissection in these patients.

Adult↗
PubMed2004

[Atherosclerosis of carotid and vertebrobasilar arteries: prognosis and therapy decision].

Atherosclerosis of carotid and vertebrobasilar arteries is a strong risk factor for ischemic stroke, as well as a strong and independent predictor of myocardial infarction and vascular death. Within the past years, the important progress made in the knowledge of carotid atherosclerosis prognosis has contrasted with the lack of studies for vertebral atherosclerosis. In patients with carotid atherosclerosis, the risk of stroke is clearly related to the severity of stenosis and the risk of recurrent ipsilateral stroke is much higher than the risk of a first-ever stroke. Patients with intracranial atherosclerosis seem to carry a high risk of stroke. Therapies for the prevention of vascular events in patients with carotid and vertebrobasilar atherosclerosis include modification of arterial risk factors, antithrombotic therapies and sometimes carotid surgery. When the benefit of surgery is very high for patients with symptomatic severe carotid stenosis, this benefit is small for those with symptomatic moderate or asymptomatic severe carotid stenosis. New medical strategies and the advantages of angioplasty are currently under investigation.

Arteriosclerosis↗
PubMed2004

Comparison of cardiovascular risk factors and drug use in 14,544 French patients with a history of myocardial infarction, ischaemic stroke and/or peripheral arterial disease.

BACKGROUND: Atherothrombosis is a systemic disease affecting coronary, cerebral, and lower limb arteries, and requiring secondary prevention measures. DESIGN: Data from three observational studies carried out in 1999-2000 (ECLAT1, APRES, PRISMA) were pooled to describe the prevalence of cardiovascular risk factors and the patterns of drug use in atherothrombotic patients. METHODS: General practitioners and cardiologists engaged in a private practice and evenly distributed in France recruited consecutive patients who had a history of at least one atherothrombotic event: myocardial infarction (MI), ischaemic stroke, and/or peripheral arterial disease (PAD). RESULTS: The sample was composed of 14 544 patients (men: 75.0%, age 75 or older: 31.0%). At least one of the four major risk factors (smoking, hypertension, hypercholesterolaemia, diabetes) was present in 94.3% of the sample. Prevalence of drug use was: 78.8% (antiplatelet agents), 48.5% (statins), 36.7% (beta-blockers), and 33.4% [angiotensin-converting enzyme (ACE) inhibitors]. After adjustment for confounders, statins were taken in a significantly larger extent in patients with a history of isolated MI than in those with a previous ischaemic stroke or PAD, or in patients who suffered from both MI and ischaemic stroke. Isolated MI (as compared with ischaemic stroke and PAD) was significantly and independently associated with a higher probability to take antiplatelet agents, beta-blockers or ACE inhibitors. CONCLUSIONS: At least one conventional risk factor was observed in almost all atherothrombotic patients. Use of preventive drugs was lower in patients with a history of ischaemic stroke or PAD, and should increase, accordingly to the results of recent randomized controlled trials.

Adult↗
PubMed2004

Stroke prevention and atrial fibrillation: reasons leading to an inappropriate management. Main results of the SAFE II study.

AIMS: The aim of the Stroke and Atrial Fibrillation Ensemble (SAFE) II study was to identify the reasons underlying the under-utilization of oral anticoagulation (OAC) in patients with nonvalvular atrial fibrillation (NVAF). METHODS: We investigated from all available sources the reasons why patients hospitalized for a stroke, who had a previously known NVAF, were not receiving OAC beforehand. We interviewed general practitioners (GPs) and cardiologists with a structured questionnaire, to identify the reasons for their therapeutic choice. RESULTS: Of 370 patients, 257 were theoretically eligible for OAC according to guidelines and the presence of contra-indications, but only 82 (22.2%) of them had actually received OAC before. We found that factors independently associated with the prescription of OAC were being followed-up by a cardiologist and having a younger GP. The leading reason evoked by GPs or cardiologists to explain why patients were not treated with OAC was the presence of a 'potential contra-indication', which was often inappropriate, followed by 'there was no indication', 'low compliance' and 'fear of bleeding'. CONCLUSIONS: An important reason for not prescribing OAC was the lack of knowledge about trials and guidelines. Medical education about OAC in NVAF should therefore be improved.

Aged↗
PubMed2003

Evaluation of hyperintense vessels on FLAIR MRI for the diagnosis of multiple intracerebral arterial stenoses.

BACKGROUND AND PURPOSE: Hyperintense vessel sign (HVS) on fluid-attenuated inversion recovery (FLAIR) has been described in hyperacute stroke patients with arterial occlusion. We sought to determine whether HVS was more frequent in patients with intracerebral arterial stenoses than in those without stenosis regardless of the presence of a brain infarct. METHODS: In this case-control study (19 symptomatic patients with multiple intracerebral arterial stenoses compared with 19 age-matched asymptomatic patients without stenosis), we looked for HVS (ie, focal or tubular hyperintensities in the subarachnoid space) on FLAIR images. We compared the proportion of HVS-positive patients in the 2 groups and evaluated the concordance between the arterial distribution of stenoses on angiogram and that of HVS on FLAIR. RESULTS: HVS was found in 13 of 19 patients (68%) in the study group and 1 of 19 control patients (5.2%) (P<0.0001). The concordance between the territorial distribution of stenoses on angiogram and HVS on FLAIR was higher for the right and left middle cerebral artery (kappa=0.6 and 0.63, respectively) compared with the right and left anterior cerebral artery (kappa=0.35 and 0.2, respectively). HVSs were observed in 1 of 7 patients with posterior cerebral artery stenoses on angiogram. HVSs were seen equally in patients with acute focal (7 of 10) or diffuse (6 of 9) cerebral involvement. In the 6 HVS-positive patients with acute stroke confirmed by MRI, additional HVSs were observed in a different arterial territory than that of the stroke lesion. CONCLUSIONS: Although their significance remains unclear, multiple HVSs are more frequently observed in symptomatic patients with multiple intracerebral stenoses than in asymptomatic patients without stenosis.

Adult↗
PubMed2002

Leigh-like encephalopathy complicating Leber's hereditary optic neuropathy.

Leber's hereditary optic neuropathy is a mitochondrial disease caused by point mutations in mitochondrial DNA. It usually presents as severe bilateral visual loss in young adults. We report on a neurological disorder resembling Leigh syndrome, which complicated Leber's hereditary optic neuropathy in three unrelated male patients harboring mitochondrial DNA mutations at nucleotide positions 3460, 14459, and 14484, respectively. This Leigh-like encephalopathy appears to be associated with a much more severe outcome than isolated Leber's hereditary optic neuropathy.

Adult↗
PubMed2002

Interobserver and intraobserver variability in detection of patent foramen ovale and atrial septal aneurysm with transesophageal echocardiography.

BACKGROUND: An accurate diagnosis of patent foramen ovale (PFO) and atrial septal aneurysm (ASA) may be of decisional importance in the management of patients with ischemic stroke. Very few studies have been devoted to observer agreement in the diagnosis of these atrial septum abnormalities using contrast transesophageal echocardiography, which is considered as the method of choice for the diagnosis. The aim of this study was to assess interobserver and intraobserver variability in the diagnosis of PFO and ASA with contrast echocardiography. METHODS: Three sonographers independently reviewed 100 contrast studies stored on videotape on 2 occasions each. The interobserver and intraobserver variability was assessed by calculating kappa statistics. RESULTS: The overall interobserver and intraobserver kappa values for the assessment of degree of shunting through a PFO were 0.77 (first and second reading) and 0.82, respectively. The best kappa statistics were obtained when no and small shunts (less than 10 microbubbles) were pooled and compared with larger shunts. For the diagnosis of ASA, the overall interobserver kappa value was 0.45 for the first reading and 0.71 for the second reading, whereas the overall intraobserver kappa value was 0.74. CONCLUSION: Interobserver and intraobserver agreements for the diagnosis of PFO and ASA by transesophageal echocardiography are not perfect and need to be improved, particularly for ASA. This variability has to be taken into account when deciding on a potential risky treatment to prevent recurrent strokes.

Adult↗
PubMed2002

Proteasome implication in phorbol ester- and GnRH-induced selective down-regulation of PKC (alpha, epsilon, zeta) in alpha T(3)-1 and L beta T(2) gonadotrope cell lines.

We investigated mechanisms underlying selective down-modulation of PKC isoforms (alpha, epsilon, zeta): 1) during 12-O-tetradecanoyl-phorbol-13 acetate (TPA) (10(-7) M) or GnRH (10(-7) M) desensitization conditions (2- to 6-h treatments) in two gonadotrope cell lines (alpha T(3)-1, L beta T(2)) and 2) in primary pituitary cell cultures from male rats during long-term phorbol ester administration. We demonstrated that, as in alpha T(3)-1 cells, in a more differentiated gonadotrope cell line L beta T(2) the GnRH-receptor coupling (PLC, PLA2, PLD) generated second messengers essential for PKCs activation; the characterized isoforms (alpha, beta II, delta, epsilon, zeta) were selectively and differentially down-regulated by TPA (alpha, beta II, delta, epsilon) or GnRH (delta, epsilon). In whole cell lysates, proteasome inhibitors (proteasome inhibitor I and II, Lactacystin, beta-Lactone, Calpain inhibitor I) prevented in both gonadotrope cell lines the TPA-induced depletion of PKC alpha, epsilon, and the GnRH-elicited PKC epsilon down-regulation; they counteracted in mixed pituitary cell cultures as well, the TPA-evoked PKC alpha, epsilon depletion. In contrast, the inhibitors of calpain(s) and lysosomal proteases (Calpeptin, E64d, Calpain inhibitor II, and PD150606), were ineffective. As shown in alpha T(3)-1 subcellular fractions, proteasome abrogation did not affect membrane translocation of TPA- and GnRH- target isoforms (alpha, epsilon) but, preventing their degradation, favored enzyme accumulation to the membrane compartment. Proteolysis processing of PKCs may be dependent upon their phosphorylated state and/or catalytic activity. Inhibition of PKC catalytic activity (GF109203X, Gö6976), selectively prevented the TPA-evoked PKC alpha depletion in both mixed pituitary cells and alpha T(3)-1 gonadotropes; in alpha T(3)-1 subcellular fractions, PKC alpha inactivation overcame the TPA-evoked isoenzyme degradation by inducing a pronounced membrane accumulation of the isoform without affecting its membrane relocalization. Thus, the proteasome system by adjusting PKC cellular levels, may represent a regulatory proteolytic pathway implicated in the adaptive mechanisms of the time dependent cell responses.

Animals↗