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Biomedical subjects

R Limet

Publications and source records attributed to R Limet.

At least 181 records · Page 10Linked to original sources
PubMed1995

Rhythmic and electrophysiological study after dynamic cardiomyoplasty.

To question the possible proarrhythmic effects of cardiomyoplasty (CMP), six adult goats were submitted to rhythmic and electrophysiological (EP) study 15 days before and 8 months after a posteroanterior clockwise CMP procedure using Medtronic Cardiomyostimulator (CMS) (SP1005) and electrodes (SP5528) and completion of a progressive stimulation protocol. Pre and postoperative screening included a surface ECG, 24-hour Holter monitoring, high amplitude and filtered QRS averaging, and invasive EP study performed in the postoperative period with the CMS "ON" and "OFF." One-hour Holter recording with desynchronization of the CMS was obtained. Comparison of pre and postoperative ECG and rhythmic data showed no significant difference. High amplitude QRS averaging did not evidence meeting the usual criteria of late potentials. EP values were stable in both conditions and the aggressive EP program did not show evidence of increased susceptibility to arrhythmias. Asynchronous cardiomyostimulation did not induce arrhythmias. Our data strongly suggest that provided meticulous surgical technique is used, CMP does not significantly interfere with the electrical characteristics of the normal goat heart. The procedure, despite the disturbances it provokes, does not seem to be arrhythmogenic. The function of the CMS was always appropriate, even under stressful EP conditions.

Animals↗
PubMed1995

[Familial risk of abdominal aortic aneurysm and its consequences for organization of selective detection].

Aneurysm of the abdominal aorta (AAA) is multifactorial disease related to acquired factors (arteriosclerosis) and genetic factors (collagen anomalies) with, in some cases, a familial component. The incidence of familial AAA was evaluated in 324 patients in 313 families who underwent surgery for AAA. A family survey was used to determine whether members of the operated patients had AAA or had died due to ruptured aneurysms. There were 276 cases (including 12 females) with sporadic AAA and 81 cases (including 5 females) who were members of families with at least one other member having AAA. Comparison between sporadic AAA (SAAA) and familial AAA (FAAA) demonstrated the following differences: 1) diagnosis was made earlier in FAAA (p < 0.05) than in SAAA (64.1 versus 66 years of age respectively), 2) patients with FAAA were younger at the time of rupture (65.4 versus 75.1 years, p < 0.001), 3) the incidence of rupture was greater in FAAA than in SAAA (32.4% versus 8.7% p < 0.001), and finally 4) the relative risk of developing AAA was 18 times greater in members of a family with AAA than in the reference population. Early screening with ultrasonic examinations in at least patient's brother's over 50 years would not be an unjustified expense. The frequency of later examinations would depend on the size of the aorta initially observed. If FAAA is evidenced, under normal conditions, corrective surgery should be proposed earlier than for sporadic AAA.

Adult↗
PubMed1994

Preservation of cortical microcirculation after kidney ischemia-reperfusion: value of an iron chelator.

Treatment of suprarenal aneurysms and renal artery reconstructions are both responsible for normothermic ischemia of the kidney (during clamping) followed by reperfusion (declamping). During reflow through an organ undergoing ischemia the production of free radicals can be associated with cell injury and a no-reflow phenomenon characterized by perfusion defects after a period of transient hyperemia. The objectives of this study were to demonstrate the existence of this phenomenon in the kidney undergoing ischemia followed by reperfusion and to test the potential protection afforded by an iron chelator (desferrioxamine) since free radical reactions are catalyzed by iron. Adult New Zealand white rabbits were divided into the following three groups: group A, 15 minutes of ischemia plus 10 minutes of reperfusion; group B, 60 minutes of ischemia plus 10 minutes of reperfusion; and group C, 60 minutes of ischemia plus 10 minutes of reperfusion combined with infusion of desferrioxamine (50 mg/kg). Cortical microcirculation in the kidney was measured by laser Doppler flowmeter before ischemia and 1, 5, and 10 minutes after reperfusion. Vitamin E content was determined in the cortex of the left kidney after 10 minutes of reperfusion and compared with that of the right (control) kidney. After 1 minute of reperfusion the cortical microcirculatory flow was significantly increased in all three groups (reactive hyperemia). In groups A and C blood flow returned to preclamping values after 10 minutes of reperfusion; however, blood flow in group B remained significantly reduced (29.2% +/- 10.5%) after 5 minutes of reperfusion with a further reduction to 48.5% +/- 5.7% after 10 minutes. These findings were correlated with the dosage of vitamin E since the vitamin E content was greatly reduced by 46.7% +/- 7.8% in group B but did not change significantly in groups A and C. This study shows that 60 minutes of normothermic ischemia is followed by a significant reduction in cortical microcirculatory flow (no-reflow phenomenon). Infusion of an iron chelator (desferrioxamine), however, which decreases the intensity of lipid peroxidation induced by the free radicals, preserves the microcirculatory flow.

Animals↗
PubMed1994

Mechanical flow obstruction after heart transplantation diagnosed by TEE.

We report a case of mechanical flow obstruction after heart transplantation caused by a prominent left atrium suture with a "pursestring" effect. The diagnosis was achieved by transesophageal echocardiography. The mean transstenotic gradient was measured at 13 mm Hg. Because of the profound hemodynamic and multisystemic failure, no surgical correction was attempted. The postmortem examination confirmed the stenosis at the level of the left atrium.

Color↗
PubMed1994

Direct evidence of free radical production after ischaemia and reperfusion and protective effect of desferrioxamine: ESR and vitamin E studies.

After surgical renal revascularisation, warm renal ischaemia due to renal artery cross-clamping contributes to postoperative renal dysfunction. After reperfusion, free radicals are thought to be a significant cause of injury. Nevertheless, indisputable proof of free radical production is scarce, partly because of their transient nature. In this study, electron paramagnetic resonance and vitamin E levels were used to demonstrate the free radical production after renal ischaemia and reperfusion. Rabbit kidneys were submitted either to 15 or 60 minutes of ischaemia followed by reperfusion. A spin trap agent (alpha-phenyl-N-tert-butyl nitrone (PBN), 20mg/ml, 1 ml/min) was infused during reperfusion directly into the left renal artery via an aortic catheter before declamping. Blood samples were selectively drawn from the left renal vein for ESR analysis (Varian spectrometer E109) of lipidic residues extracted from blood samples. The vitamin E content of the left renal cortex was determined by HPLC procedure. The right renal cortex was used as a control for the vitamin E values. In the venous effluent, ESR analysis revealed the formation of a spectrum consisting of a triplet of asymmetric doublets. This signal resulted from the spin trapping by PBN of a mixture of both oxygen- and carbon- centred lipidic radicals. The amplitude of the signal which is proportional to the amount of free radicals was significantly higher after 60 minutes ischaemia than after 15 minutes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗