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Biomedical subjects

F Leclercq

Publications and source records attributed to F Leclercq.

At least 55 records · Page 3Linked to original sources
PubMed1997

Effect of the direct nitric oxide donors linsidomine and molsidomine on angiographic restenosis after coronary balloon angioplasty. The ACCORD Study. Angioplastic Coronaire Corvasal Diltiazem.

BACKGROUND: Nitric oxide (NO) donors, in addition to their vasodilator effect, decrease platelet aggregation and inhibit vascular smooth muscle cell proliferation. These actions could have beneficial effects on restenosis after coronary balloon angioplasty. METHODS AND RESULTS: In a prospective multicenter, randomized trial, 700 stable coronary patients scheduled for angioplasty received direct NO donors (infusion of linsidomine followed by oral molsidomine) or oral diltiazem. Treatment was started before angioplasty and continued until 12 to 24 hours before follow-up angiography at 6 months. The primary study end point was minimal lumen diameter, assessed by quantitative coronary angiography, 6 months after balloon angioplasty. Clinical variables were well matched in both groups. However, despite intracoronary administration of isosorbide dinitrate, the reference diameter in the NO donor group was significantly greater than in the diltiazem group on the preangioplasty, postangioplasty, and follow-up angiograms. Pretreatment with an NO donor was associated with a modest improvement in the immediate angiographic result compared with pretreatment with diltiazem (minimum luminal diameter, 1.94 versus 1.81 mm; P = .001); this improvement was maintained at the 6-month angiographic follow-up (minimal lumen diameter, 1.54 versus 1.38 mm; P = .007). The extent of late luminal narrowing did not differ significantly between groups (loss index in the NO donor and diltiazam groups, 0.35 +/- 0.78 and 0.46 +/- 0.74, respectively; P = .103). Restenosis, defined as a binary variable (> or = 50% stenosis), occurred less often in the NO donor group (38.0% versus 46.5%; P = .026). Combined major clinical events (death, nonfatal myocardial infarction, and coronary revascularization) were similar in the two groups (32.2% versus 32.4%). CONCLUSIONS: Treatment with linsidomine and molsidomine was associated with a modest improvement in the long-term angiographic result after angioplasty but had no effect on clinical outcome. The improved angiographic result related predominantly to a better immediate procedural result, because late luminal loss did not differ significantly between groups.

Aged↗
PubMed1997

Chronic left main coronary artery occlusion: a complication of radiofrequency ablation of idiopathic left ventricular tachycardia.

We describe in this report the development of chronic left main coronary artery (LMCA) occlusion in a young patient 2 years after an uncomplicated, successful ablation of idiopathic left ventricular tachycardia. This complication appears to be a late consequence of trauma to the LMCA during the procedure rather than an acute or subacute embolic event.

Adult↗
PubMed1997

[Classification of regular atrial tachycardia].

ECG criteria which for many years formed the basis of the classification of regular atrial tachycardias may now be completed by the results of endocavitary studies (stimulation and mapping). Flutter is a macroreentry phenomenon in the right atrium, anticlockwise in typical, common or classical forms, and more variable in atypical forms: sometimes antidromic and clockwise, sometimes functional more rapid without a gap of excitability, or in other cases, skirting around the sears of atriotomy, especially right-sided. Tachycardias are paroxysmal and often secondary to reentry; more rarely permanent, they are then often due to increased automaticity especially in young patients. The concordance with surface ECG changes is not perfect and the distinction between flutter and tachycardia often depends on the frequency of the tachycardia and the leads studied.

Anti-Arrhythmia Agents↗
PubMed1996

Exercise tolerance in patients with mitral stenosis before and after acute percutaneous mitral valvuloplasty. Role of lung diffusing capacity limitation?

The aim of this study was to specify in patients with tight mitral stenosis whether lung diffusing capacity could play a role in their exercise intolerance. A similar study was recently carried out in patients with moderate chronic heart failure. Ten patients with tight mitral stenosis were studied before and 6 months after successful percutaneous transvenous balloon valvuloplasty and compared to six control subjects. Measurements of diffusing capacity, evaluated by the lung transfer factor (TLCO) and by the transfer coefficient (TLCO/VA), obtained at rest and during early recovery after cardiopulmonary exercise testing were performed. Cardiac output was determined non-invasively, both at rest and during exercise, using the carbon dioxide exponential rebreathing technique. Prior to valvuloplasty, TLCO and TLCO/VA were not different at rest between the two groups. During exercise, patients differed from control subjects, with lower oxygen uptake (P < 0.001) and lower cardiac output at peak exercise (P < 0.001). These values at peak exercise were significantly correlated (P = 0.02; r = 0.75). Moreover, patients differed from control subjects at early recovery after peak exercise with an absence of increase in TLCO (P < 0.05). Six months after valvuloplasty, a decrease of both TLCO (P < 0.01) and TLCO/VA (P < 0.05) was observed at rest. During exercise, comparison of patients demonstrated a significant increase of both peak exercise oxygen uptake (SLVO2, P < 0.01) and cardiac output (P < 0.001). At early recovery after peak exercise there was a significant increase in TLCO (P < 0.05) and TLCO/VA (P < 0.01), such that a delta TLCO and a delta TLCO/VA appeared (P < 0.05) identical to that observed in control subjects. Moreover, delta SLVO2 was significantly correlated in patients with delta Q+ delta TLCO/VA (P = 0.02; r = 0.72). In conclusion, this study suggests a role, at least partial, of lung diffusing capacity in exercise intolerance in patients with tight mitral stenosis and in the improvement of their aerobic exercise capacity demonstrated after successful percutaneous balloon valvuloplasty.

Adult↗
PubMed1996

[Mechanisms of restenosis after coronary angioplasty].

Coronary restenosis is the direct result of arterial trauma caused by angioplasty and therefore affects all patients to different degrees. Fracture of the plaque extending to the media is the principal mechanism of increase of the arterial lumen after balloon angioplasty, wall stretching concerning mainly excentric lesions. Atherectomy causes pulverisation of excision of the plaque without fracture. Stents reduce the amount of debris and the torn appearances of the plaque often observed after angioplasty. Four mechanisms are involved in the induction of restenosis: neointimal hyperplasia, proportional to the amount of trauma (damage to the internal elastic layer), related to proliferation of smooth muscle cells migrating from the media to the intima nad stimulated by many growth factors: defective remodelling or chronic elastic recoil, characterised by a reduction of the arterial lumen at the angioplasty site; acute elastic recoil in the first minutes or hours after angioplasty, mainly observed in excentric lesions; thrombosis, whose role is secondary except in certain clinical situations such as unstable angina, angioplasty of saphenous vein grafts or long dissections. The classical theories of restensosis attribute a major role to initial hyperplasia but more recent experimental and clinical data, obtained largely from endocoronary ultrasonography, suggest that defective remodelling may be more important. Although endocoronary stents prevent acute and chronic elastic recoil effectively, they do not prevent restenosis which remains a complex, multifactorial phenomenon.

Angioplasty, Balloon, Coronary↗
PubMed1995

Interferon alpha/beta-induced abnormalities in adipocytes of suckling mice.

The modification induced by interferon (IFN) in brown adipose tissue (BAT) was studied by high spatial resolution magnetic resonance imaging (MRI), histology, and transmission electron microscopy (TEM). In IFN-treated mice, at MRI, the interscapular BAT was slightly enlarged and showed non-homogeneous areas of lipid accumulation. The thickness of the subcutaneous white adipose tissue was reduced with respect to control mice. In the liver, MRI showed a lipid accumulation. In IFN-treated mice, by light microscopy, brown adipocytes showed a larger lipid deposit with respect to control mice. At TEM, in BAT, the mitochondria were reduced in number, smaller and the number of cristae was also significantly reduced with respect to the controls (9.1 +/- 1.5 vs 20.1 +/- 1.9, P < 0.01). The inclusions in the mitochondrial matrix were significantly less numerous in IFN-treated than in control animals (1.9 +/- 0.7 vs 0.9 +/- 0.7 for mitochondrial section, P < 0.01). Abnormalities of endoplasmic reticulum described in hepatocytes were not found in brown adipocytes of IFN-treated mice. The present work demonstrates that, in the BAT of suckling mice, IFN-treatment induces morphologic alterations and that brown adipocytes have MRI and TEM features resembling those found in the lipid laden BAT of aged animals.

Adipocytes↗
PubMed1995

Enalapril in the treatment of mild-to-moderate heart failure in general medical practice: a prospective and multicentre study concerning 17,546 patients.

The objective of this study was to test the efficacy and tolerability of a precise dosage regimen of enalapril in general medical practice, in combination with conventional therapy, in patients with mild-to-moderate (NYHA classes II and III) congestive heart failure (CHF). 17,546 patients were prospectively included in this multicentre study. After three months of treatment with enalapril, 53.9% of patients were asymptomatic (NYHA Class I) and 75.1% of patients improved by at least one class in the NYHA classification. 64.6% of patients reached maintenance dosage of 20 mg/day of enalapril and mean daily dosage for all patients was 16 mg. Outcome of functional symptoms according to NYHA class was more favourable with maintenance dosages of 15 and 20 mg/day of enalapril than with maintenance dosages of 5 and 10 mg/day of enalapril. Clinical and laboratory safety was good with low rates observed of the main adverse events: cough (1.74%), hypotension (0.34%), postular hypotension (0.30%), dizziness (0.31%) and hyperkaliema (0.13%); 1.4% of patients dropped out of the study because of such events. This extensive and open study confirms, in general medical practice, the feasibility, efficacy and tolerability of a dosage regimen of enalapril, which has been previously determined in controlled studies performed in specialized medical centres, for treatment of mild-to-moderate heart failure.

Aged↗
PubMed1995

[Atrioventricular nodal tachycardia].

The atrioventricular junction consists of the atrioventricular node and the bundle of His up to its division. All tachycardias arising in these structures or which depend on these structures for their sustenance are called "junctional". There are four main types. The first three correspond to reciprocating rhythms, nodal tachycardia, tachycardias using an accessory pathway with unidirectional retrograde conduction, and chronic reciprocating atrioventricular nodal tachycardia. All varieties of reciprocating atrioventricular nodal tachycardia have been well studied and their diagnosis is possible from the standard surface electrocardiogram from the position and morphology of the P' wave. They are accessible to radical treatment by radiofrequency ablation of the slow pathway or accessory pathway, when present. The definitive treatment of ectopic atrioventricular nodal tachycardia is not yet established and has to be considered case by case, this form of arrhythmia being rare.

Anti-Arrhythmia Agents↗
PubMed1995

[Transient entrainment of tachycardia].

Transient entrainment of tachycardia by pacing at a faster rate corresponds to its acceleration with return to sinus rhythm either when the pacing is interrupted or when the pacing rate is slowed. It conforms to strict criteria detectable either on the surface electrocardiogramme (constant fusion, progressive fusion, change of morphology before termination of a tachycardia) or on selective endocavitary recording when entrainment is hidden. The phenomenon described by Waldo in 1977 in atrial flutter is found in all reentrant tachycardias. It is currently being studied in ventricular tachycardia. The electrophysiological concept is useful because it facilitates the understanding of the mode of termination of tachycardia by stimulation and the localisation of zones for destruction during ablation.

Cardiac Pacing, Artificial↗
PubMed1994

Magnetic resonance imaging of the submandibular-sublingual complex.

The submandibular-sublingual complex (SSC) was studied in vivo by magnetic resonance imaging (MRI) at 4.7 and 7.05 Tesla in rat and mouse. A correlation was found between histology and MRI signal. The mainly mucous sublingual gland emitted a more intense signal than the mainly serous submandibular gland. Ventral to the glands, cutis, subcutaneous adipose tissue and two planes of muscular tissue separated by connective laminae were visible in vivo. Autopsy and histology confirmed the in vivo description provided by MRI. The reactivity of the salivary system after pharmacological stimulation was studied in mice at 7.05 Tesla. Stimulation of salivary secretion by pilocarpine nitrate injected in the subcutaneous space ventrally to the SSC resulted in an augmentation of the salivary liquid visible in the oral cavity by MRI. The diffusion of pilocarpine nitrate in the connective tissue located ventrally the SSC and in the glandular parenchyma was also followed in vivo. These results show that MRI is a potentially useful tool for studying the salivary glands in vivo.

Animals↗
PubMed1994

[Electrocardiographic aspects of sinoatrial block].

There are many electrocardiographic changes in sinoatrial block. Only 2nd and 3rd degree blocks can be analysed on surface recordings. However, they manifest themselves by pauses, the descriptions of which are rich and varied. They also vary according to the circumstances of apparition and the escape rhythms which accompany them. Related ECG changes such as chronotropic insufficiency or carotid sinus syndrome have been described. However, their significance is not univocal and only a precise analysis of the ECG recordings allows correct interpretation of the clinical and paraclinical signs and the institution of appropriate therapy.

Cardiac Complexes, Premature↗
PubMed1994

[Floating thrombus in the right atrium and severe pulmonary embolism. Value of intravenous thrombolysis].

Mobile right atrial thrombi carry a high risk of pulmonary embolism which may be massive and are a medical emergency. Although surgery is commonly indicated, treatment with intravenous thrombolytics is an alternative and was successful in 4 out of 6 cases reported by the authors. Six patients, admitted for severe pulmonary embolism confirmed by pulmonary scintigraphy (6 cases) and by angiography (2 cases), underwent echocardiography which demonstrated a mobile right atrial thrombus. One patient was operated as an emergency and died immediately afterwards. Another, treated with heparin because of contraindications to surgery and thrombolysis had a recurrent fatal pulmonary embolism. In the other four cases, intravenous thrombolytic therapy was started immediately after echocardiography with 250,000 IU of streptokinase in 30 minutes, followed by 100,000 IU per hour for 48 to 72 hours associated with heparin 300 to 500 IU/kg/day. The biological efficacy of the treatment was confirmed in all cases (fibrinogen < 1 milligram; TCA > 60 s). A clinical improvement with improved blood gases was rapidly obtained in all 4 cases. The thrombus had totally disappeared at control echocardiography 8 to 12 hours after the initial examination. There were no complications, in particular no haemorrhages. After 6 months' follow-up, the outcome was good with oral anticoagulants (4 cases) associated with implantation of a caval filter in 1 case. Thrombolysis seems to be an effective alternative to surgery as there four cases demonstrate.

Aged↗
PubMed1994

[Surgery for arrhythmias].

The role of surgery in the treatment of cardiac arrhythmias has been marginalized in recent years with the rise in eminence of radiofrequency current ablation especially in the Wolff-Parkinson-White syndrome and nodal reentrant tachycardia. The indications of antiarrhythmia surgery for ventricular arrhythmias have become standardised. The unquestioned efficacy of the surgical techniques proposed (endarterectomy or cryosurgery with or without peroperative mapping) should not be associated with unacceptable mortality rates as when left ventricular function is too poor, implantation of a defibrillator is always possible. In the domain of atrial fibrillation, the interventions proposed (corridor or maze procedures) do not have the foundations that the follow-up of a sufficient number of cases would confer but they have the merit, especially the latter, of taking the underlying physiopathological mechanisms into consideration.

Arrhythmias, Cardiac↗
PubMed1994

[Pre- and postoperative ventricular arrhythmia in mitral valve insufficiency].

In order to assess the prevalence and prognosis of ventricular arrhythmias in patients with surgical mitral regurgitation, a prospective cooperative study was undertaken in 14 French cardiological centres. Seventy-nine patients (45 men, 34 women, average age 62.8 +/- 12.8 years), who underwent mitral valvuloplasty (44 cases) or valve replacement (35 cases), were included. Three 24 hour Holter recordings were performed before, 15 days and 6 months after surgery. Etiology of mitral disease was dystrophic in 49 patients, degenerative in 11, rheumatic in 10, post-endocarditis in 3 and undetermined in 6. Only 5 patients had a left ventricular ejection fraction < or = 45 %. Complex ventricular arrhythmias (Lown > or = 4) were recorded before surgery in 22 patients (28 %), more often in dystrophic disease (17/49 versus 5/30, p = 0.04). No significant correlation was observed between the ventricular arrhythmias and the other preoperative findings, except for a tendency to an inverse correlation between the left ventricular ejection fraction and the Lown grade. Two patients died in the immediate postoperative period (Lown 1); 1 died of a non-cardiac cause at the 2nd month (Lown 4A). The prevalence of complex arrhythmias was unchanged after surgery (34 % on early Holter and 22% on late Holter recordings) with no difference between valvuloplasty and valve replacement. In conclusion, these results indicate that ventricular arrhythmias do not influence the early and 6 month postoperative prognosis in mitral regurgitation with good left ventricular function.

Aged↗
PubMed1994

Adult coronary aneurysms related to Kawasaki disease.

Kawasaki disease (KD) is an acute illness encountered in infancy and childhood. Cardiovascular complications of this syndrome are recognized as being part of the adult coronary artery disease population. Reported herein is the surgical treatment of multiple coronary artery aneurysms, severe stenotic lesions and thrombotic involvement of the coronary arterial tree that could be ascribed to childhood KD in two adult patients with no risk factors for atherosclerotic heart disease. Surgical management of such patients reveals safe and provides satisfactory quality of life.

Adult↗
PubMed1993

Synthesis and antineoplastic properties of 3'-deoxy-3'-fluoroketonucleoside derivatives. Correlations between structure and biological activity.

Three fluoroketonucleosides (6, 8, and 11) have been synthesized by direct oxidation of the fluoro precursors. The presence of the highly electronegative fluorine atom in the alpha position to the carbonyl group favours hydration leading to the gem-diol form so that the beta-elimination process to afford 6 and 8 was made difficult and failed in the case of the difluoro compound 11. The biological activity of compounds 6, 8, and 11 was tested on human peripherical blood lymphocytes stimulated by PHA, and on RAJI and DAUDI cells. The IC50 values showed that, surprisingly, the 3'-enopyranosyl-2'-uloses 6 and 8 have much better antineoplastic activities than their 2'-enopyranosyl-4'-ulose analogues 14 and 15 obtained previously. Moreover, compound 11, which is difluorinated at C-3' and C-6' but does not have a C = C-C = O group in its structure, is also very active. These results emphasize the important biological role played by the fluorine atom in this family of compounds and suggest a peculiar mechanism of action which is until now unspecified.

Antineoplastic Agents↗