Alain Tabib - Academia.edu (original) (raw)

Papers by Alain Tabib

Archives de Pédiatrie, 2005

There is only a few data on sudden unexpected death (SUD) in the pediatric population, as well as... more There is only a few data on sudden unexpected death (SUD) in the pediatric population, as well as the role of sport.Materials and methods. – Between 1980 and 2003, 2220 autopsies were performed at the Lyon&amp;amp;amp;#39;s forensic institute for SUD (all ages) as defined by world health organization.Results. – Fifty-seven cases of SUD of cardiac origin concerned 6 to 18-year-old

The retrospective analysis of 1500 forensic autopsies after sudden cardiac death showed that 80 (... more The retrospective analysis of 1500 forensic autopsies after sudden cardiac death showed that 80 (77 men, three women) had died following sport, for which they had been inadequately trained. The chosen sport (both dynamic and static), and the cardiac pathology discovered during autopsy make it possible to divide the population into two groups. Group 1 were those under 30 years

The Journal of Trace Elements in Experimental Medicine, 1999

Oxidative stress is involved in diabetes mellitus and its complications. Selenium is a nutritiona... more Oxidative stress is involved in diabetes mellitus and its complications. Selenium is a nutritional antioxidant, especially because it is required for the activity of seleniumdependent glutathione peroxidase. Selenium also may have insulin-like properties and improve insulin sensitivity. However, its effects are not sufficiently documented in diabetes and its complications. Thus we supplemented type I diabetic rats with a selenium-rich yeast, selenomethionine and selenomethionine + vitamin E for 24 weeks. Selenium supplementations increased selenium levels in plasma. Selenium and more efficiently Sm + vitamin E decreased plasma glucose level and glycated hemoglobin. Supplementations increased selenium levels in kidney and double supplementation increased renal vitamin E level. However, no differences were observed in thiobarbituric acid-reactive substances in kidneys in the different groups. Selenium decreased or normalized the increased arachidonic acid content observed in diabetic kidneys and so may reduce the level of thromboxane involved in nephropathy. Glomerular hyperfiltration is common in early stages of diabetic nephropathy. We observed an increased renal creatinine clearance in diabetic rats, indicating renal hyperfiltration. Nevertheless, this hyperfiltration was corrected by selenium supplementations. Renal lesions were markedly increased in diabetic rats, but very significantly reduced or corrected by supplementations. Thus we concluded that selenium supplementation could be a useful additive therapeutic to delay diabetic nephropathy.

Canadian journal of psychiatry. Revue canadienne de psychiatrie, 2004

To confirm the hypothesis that psychotropic drugs, especially neuroleptics, lithium, and antidepr... more To confirm the hypothesis that psychotropic drugs, especially neuroleptics, lithium, and antidepressants, are implicated as a cause of unexpected sudden death in psychiatric patients because of their cardiotoxicity, especially when hidden cardiac lesions are present. We performed a full pathological examination of 14 psychiatric patients who unexpectedly and suddenly died between 1980 and 1999. Neuroleptics were involved in 13 instances, antidepressants in 9, and anxiolytics in 5. Psychotropic drugs were combined in all but a single patient. In all 14 patients, toxicological analyses discarded drug overdose as cause of death. At postmortem examination, the brain and abdominal organs were normal. In 13 patients, the following lesions were found in the heart and lungs: dilated cardiomyopathy (6 patients), left ventricular hypertrophy (2 patients, 1 of which was associated with mitral prolapse and anomalies of His bundle), arrhythmogenic cardiopathy of the right ventricle (1 patient), ...

Journal de Radiologie, 2006

Research in virology

The postmortem anatomopathological examination of eight heart-and-lung specimens obtained from ei... more The postmortem anatomopathological examination of eight heart-and-lung specimens obtained from eight HIV-seropositive patients was performed. Three patients were CDC stage II and five patients were CDC stage IV. The mean age was 27 (range: 23-32). Distal and proximal vascular lesions of the coronary arteries were observed. These impairments were marked by major excentric atherosclerosis (with 80-90% obstruction of the arterial lumen) or by fibrosis two-fold or six-fold the thickness of the tunica media. Sclero-hyalinosis of the smaller arteries and myocardial interstitial fibrosis lesions was also revealed. In view of the severity of the described lesions, the absence of any associated cardiovascular risk factors and the context of immunodepression, the role of a virus in the genesis of these lesions is suggested, in particular a virus of the herpes group.

European Journal of Heart Failure Supplements, 2006

... 353 Elevated plasma markers of matrix metalloproteinases type 2 and 9 are independent predict... more ... 353 Elevated plasma markers of matrix metalloproteinases type 2 and 9 are independent predictors of diastolic heart failure R. Martos 1 , J. B augh 2, M ... Anna University Hospital, 1st Internal Cardioangiological Dept., Brno, Czech Republic; 2Brno University Hospital, Dep. ...

Cardiovascular Toxicology, 2009

Further to our previous observation of post-mortem cardiac lesions after sudden death in several ... more Further to our previous observation of post-mortem cardiac lesions after sudden death in several athletes with a history of anabolic steroid abuse, this study was intended to reproduce these lesions in rabbits administered testosterone oenanthate, a prototypic anabolic steroid abused by athletes, and to provide evidence for the protective effects of trimetazidine and dexrazoxane that are used as antianginal and cardioprotective drugs, respectively. Groups of six rabbits each were administered saline, testosterone, or a combination of testosterone and either trimetazidine or dexrazoxane for 3 months. Histologic cardiac lesions including necrosis, misshapen cell nuclei, interstitial and endocardial fibrosis, lymphocytic infiltrates, and vascular dystrophies were observed in testosterone-treated rabbits. In contrast, no significant lesions were observed in the animals treated with testosterone combined with either trimetazidine or dexrazoxane. This is the first study providing evidence for testosterone cardiotoxicity following sub-chronic exposure in laboratory animals. In addition, these results suggest the protective role of trimetazidine and dexrazoxane.

Ultrasound in Medicine & Biology, 1997

The intravascular ultrasound image of the intrahnninal contour depends on the difference between ... more The intravascular ultrasound image of the intrahnninal contour depends on the difference between acoustic impedances of the medii which create the endoluminal interface. There are several limitations to the visualization and detection of this interface. These limitations are due to artifacts encountered during image formation and to anatomical complexity. The purpose of this study is to obtain intrakmhnd contour enhancement using ultrasound contrast agent (UCA). Therefore, our objective was to address the feasibility of this technique by documenting the following: (i) the acoustic properties of UCA at 30 MI&; (ii) in vitro experimentation with tube or postnecrotic artery; and (iii) suitable digital processing. The images obtah& with UCA (enhanced image quality) and subtracted from those without UCA provided, after simple dfgital processing, accurate visualization of the arterial lumen. The image obtained exhibits an even, high-contrast intraluminal edge. Such characteristics facilitate contour extraction by the automated contour detection procedures. 0 1997 World Federation for Ultrasound in Medicine and Biology.

Ultrasound in Medicine & Biology, 1993

The ability of an intravascular ultrasound catheter to give cross-sectional images of vessel wall... more The ability of an intravascular ultrasound catheter to give cross-sectional images of vessel walls and surrounding tissues, and the behavior of ultrasound in heterogeneous media, are at the origin of degradation of image quality. Qualitative and quantitative analyses of in vivo studies are then operator-dependent and are limited by artifacts. We investigated these limitations by an in vitro study on plexiglass phantoms and segments of fresh arteries. We used a 20 MHz transducer mounted on the tip of a 4.8 F catheter and an interventional ultrasound system. The ultrasound beam is reflected onto the rotating transducer at 600 rotations per minute (RPM), creating 360 ° real-time images (10 images/second). We then observed, analyzed and interpreted the most specific reasons for image artifacts: geometric distortions, multiple echoes, the point spread function (PSF) of the imaging system, near-field effects, "petal-shaped" effect, and ultrasound speckle. Various practical implications have resulted from this study. Only a thorough knowledge of how to avoid some of the most obvious pitfalls will enable the user to obtain maximum benefits from intravascular ultrasound imaging, and to appreciate its limitations.

Resuscitation, 2011

Aims: We showed previously that ivabradine (IVA), a selective inhibitor of the cardiac pacemaker ... more Aims: We showed previously that ivabradine (IVA), a selective inhibitor of the cardiac pacemaker I f current, achieved protection against ischaemia-induced ventricular fibrillation (VF) in pigs by increasing the VF threshold (VFT). This was correlated to the heart rate reduction (HRR), the limitation of monophasic action potential shortening and the reduction of the hypoxic area. This study investigated myocyte ultrastructure and regional myocardial blood flow (RMBF), potentially involved in these cardioprotective effects of IVA. Methods and results: Myocardial ischaemia was induced in pigs by total 1-min occlusion of the left anterior descending coronary artery following i.v. administration of saline (n = 6) or IVA (0.25 mg/kg, n = 6). Electrophysiological and haemodynamic parameters, the hypoxic area and the presence of myocyte ultrastructural lesions were evaluated. The RMBF was assessed using positron emission tomography following ischaemia/reperfusion in IVA (0.25 mg/kg, i.v., n = 6) or vagal stimulation (n = 4) groups. Compared with saline, IVA induced a 32% HRR (p < 0.01), a 2.9-fold increase in the VFT (p < 0.001) and a reduction of the hypoxic area without any change in left ventricular dP/dt max . IVA preserved cardiomyocyte morphology, particularly mitochondrial ultrastructure. Compared with baseline, RMBF during reperfusion was increased in the hypoxic area following IVA administration (+218% vs. +97%, p < 0.05) or vagal stimulation (+195% vs. +127%, p < 0.05). This increase was sharply reduced by atrial pacing in IVA-group. Conclusion: IVA exerts a cardioprotection from ischaemia-induced VF by increasing RMBF and preserving cardiomyocyte and mitochondrial ultrastructure, which opens new perspectives regarding potential targets that would be involved in the anti-ischaemic effects of IVA.

Pacing and Clinical Electrophysiology, 1999

Epicardial radiofrequency catheter ablation of the atria in the open-chest dog has been shown to ... more Epicardial radiofrequency catheter ablation of the atria in the open-chest dog has been shown to reduce inducibility of atrial fibrillation. Video-assisted endoscopic techniques decrease the operative trauma in adult thoracic surgery. We report our results of video-assisted thoracoscopic radiofrequency catheter ablation of the atria for the prevention of atrial fibrillation induction in canines. In 12 consecutive anesthetized dogs, induction of sustained atrial fibrillation was reproducibly obtained by burst pacing and cervical vagal stimulation. In six dogs, biatrial ablation was performed through right and left minithoracotomies and guided by video-assisted endoscopic techniques. The remaining six dogs underwent a video-guided left atrial procedure. Long continuous and transmural lesions were produced using epicardial temperature controlled radiofrequency energy delivery according to a simplified maze approach. Transmural lesions were demonstrated at the end of the study by examination of the heart. Sustained atrial fibrillation was still inducible after the right atrial ablation but sustained atrial fibrillation could not be induced following left atrial ablation. In acute canine studies: (1) epicardial radiofrequency catheter ablation of the atria is feasible using video-assisted endoscopic techniques; (2) ablation extended or confined to the left atrium appears to be effective in preventing the inducibility of sustained vagal atrial fibrillation; and (3) ablation of the right atrium alone had no antiarrhythmic effect.

Journal of Molecular and Cellular Cardiology, 2007

Journal of Forensic and Legal Medicine, 2010

Sudden cardiac deaths constitute a major health problem. Most cases are attributed to cardiomyopa... more Sudden cardiac deaths constitute a major health problem. Most cases are attributed to cardiomyopathies, coronary artery diseases and functional dysregulations. Sudden death in an adult due to a primitive cardiac tumor is a rare occurrence. In the following, we present a case of an adult male who died from an undiagnosed cystic atrio-ventricular node tumour six years after having a pace maker fitted. We focus on the postmortem diagnosis to underline the importance of a systematic histological examination of the cardiac conduction tissue in forensic pathology.

Journal of Cardiovascular Pharmacology, 2008

Tachycardia often facilitates ischemic ventricular fibrillation (VF). This study assessed the imp... more Tachycardia often facilitates ischemic ventricular fibrillation (VF). This study assessed the impact of ivabradine (IVA), a selective inhibitor of the cardiac pacemaker If current, on ventricular fibrillation threshold (VFT) during acute myocardial ischemia. The experiments were conducted on a total of 54 domestic pigs. Myocardial ischemia was induced in anesthetized pigs by total 1-minute coronary occlusion at baseline and then on 2 occasions after intravenous administration of saline or 0.5 mg/kg of IVA. VF was triggered by electrical stimuli of increasing intensity at a fixed rate. Heart rate (HR), VFT, monophasic action potential duration, and peak of the time derivative of left ventricular pressure (LV dP/dt max) were monitored on each occasion. The activity of mitochondrial succinodehydrogenase was measured on heart sections. Compared with controls, IVA induced a 31% reduction in HR, a 2.9-fold increase in VFT, and prevented ischemia-induced monophasic action potential duration shortening (+1 +/- 12 vs. -14 +/- 11 milliseconds) without affecting peak LV dP/dt. This beneficial effect on VFT was mainly due to HR reduction and was accompanied by a significant reduction in the hypoxic area (26% +/- 1% vs. 38% +/- 1%, P &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;lt; 0.0001). HR reduction and the decrease in myocardial damage induced by IVA protected against primary ischemic VF without altering myocardial contractility.

Journal of Applied Toxicology, 2008

Organic and/or functional heart lesions sometimes resulting in sudden death have been described i... more Organic and/or functional heart lesions sometimes resulting in sudden death have been described in psychiatric patients treated with neuroleptics. As selenium has been suggested previously to play a role in the development of such lesions, the present study was undertaken to determine whether a correlation could be found between heart lesions induced by neuroleptics and changes in blood selenium as well as myocardial tissue concentrations in the rabbit. Twelve NZW adult rabbits were treated intramuscularly with both levomepromazine 3 mg kg − − − − −1 day − − − − −1 ) and risperidone (1 mg kg − − −

Journal of Anesthesia, 2006

A major risk associated with bupivacaine during myocardial ischemia is ventricular fibrillation. ... more A major risk associated with bupivacaine during myocardial ischemia is ventricular fibrillation. We investigated the influence of ropivacaine on cardiac contractility and the propensity to ventricular fibrillation before and after myocardial ischemia in a placebo-controlled pig study. Anesthetized domestic pigs were administered 1 mg.kg(-1) of ropivacaine intravenously over 1 min and then 0.03 mg.kg(-1).min(-1) as a 30-min infusion, or saline. The following endpoints were measured before and after ropivacaine administration: (1) the ventricular fibrillation threshold (VFT) before and during myocardial ischemia induced by total transient ligation of the anterior interventricular artery and (2) electrophysiological (sinus heart rate, duration of QRS and QT intervals) and hemodynamic (blood pressure, the time derivative of left ventricular pressure [peak LV dP/dt]) parameters. Ropivacaine induced no changes in sinus heart rate, QRS, and or QT before or during ischemia. In contrast, there was a mild increase in the VFT before ischemia, which was drastically and significantly reduced during ischemia. The reduction of peak LV dP/dt during ischemia was further increased by ropivacaine. We also found that the effect of ropivacaine on the VFT was coronary blood flow-dependent, with a markedly decreased threshold in the presence of ischemia. Similar effects have been observed in humans with several other local anesthetics, as well as with class I antiarrhythmic drugs. The results of this study should be taken into account by anesthesiologists when administering ropivacaine to coronary patients.

The International Journal of Cardiovascular Imaging, 2010

The present study investigated whether IVUS could serve as a reliable reference in validating MDC... more The present study investigated whether IVUS could serve as a reliable reference in validating MDCT characterization of coronary plaque against a histological gold standard. Twenty-one specimens were postmortem human coronary arteries. Coronary cross-sections were imaged by 40 MHz IVUS and by 64-slice MDCT and characterized histologically as presenting calcified, fibrous or lipid-rich plaques. Plaque composition was analyzed visually and intra-plaque MDCT attenuation was measured in Hounsfield Units (HU). 83 atherosclerotic plaques were identified. IVUS failed to characterize calcified plaque accurately, with a positive predictive value (ppv) of 75% versus 100% for MDCT. Lipid-rich plaque was even less accurately characterized, with ppv of 60 and 68% for IVUS and MDCT respectively. Mean MDCT attenuation was 966 +/- 473 HU for calcified plaque, 83 +/- 35 HU for fibrous plaque and 70.92 HU +/- 41 HU for lipid-rich plaque. No significant difference in mean MDCT attenuation was found between fibrous and lipid-rich plaques (P = 0.276). In vivo validation of MDCT against an IVUS reference thus appears to be an unsuitable and unreliable approach: 40 MHz IVUS suffers from acoustic ambiguities in plaque characterization, and 64-slice MDCT fails to analyze plaque morphology and components accurately.