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Biomedical subjects

M Toussaint

Publications and source records attributed to M Toussaint.

At least 73 records · Page 4Linked to original sources
PubMed1988

[Tight mitral stenosis caused by calcifications of the ring extending to the valves].

Three years after valve replacement for Monckeberg type aortic stenosis, a tight and poorly tolerated tight mitral stenosis is observed, secondary to massive calcifications of the ring extending to the valves. The diagnosis is made with Doppler sonography and hemodynamic examination. Excision of the calcifications is particularly difficult. An early death occurs. Calcifications of the mitral ring extending to the valves, either isolated or mainly associated with a calcified aortic stenosis, may be complicated by mitral stenosis. The latter, usually moderate, may be tight and require surgical treatment, of severe prognosis.

Calcinosis↗
PubMed1987

Left ventricular ultrastructure in pulmonary stenosis and in tetralogy of Fallot.

Twelve patients underwent haemodynamic studies and myocardial biopsies: 7 with pulmonary stenosis (PS) and 5 with tetralogy of Fallot (TOF). Their ages ranged between 2 and 43 years. Right ventricular pressure was 128 +/- 43 mmHg in PS and 98 +/- 8 mmHg in TOF. Aortic blood oxygen saturation was 97.0% +/- 1.4% in PS, and 88.4% +/- 6.3% in TOF. Left ventricular (LV) weight was normal in TOF while it was increased in PS: 140.7 +/- 74.3 vs 74.0 +/- 8.7 g/m2 (P less than 0.001). Contractility was altered in both PS and TOF: ejection fractions were 56% +/- 7% vs 65% +/- 6% (P less than 0.001). Light microscopy showed abnormal transverse diameter of left ventricular myocytes in both PS and TOF: 18.6 micron +/- 4.0 micron vs 19.4 micron +/- 4.9 micron. The percentage of interstitium was normal: 29.6% +/- 3.9% vs 26.2 +/- 5.1%. Transmission electron microscopic examination revealed hypertrophic changes in all patients and degeneration in 7 of them. Hyperfunctional alterations of the myocytes were characterized by the increased number and reduced size of mitochondria, the enlarged Golgi complex, the increased number of ribosomes, the marked folding and convolutions of the nuclear membrane, the dilatation and tortuosity of T tubules. Myofibrillar lysis was the major degenerative change, which was also observed in the right ventricle (RV) of the same patients. No correlation was observed between these alterations and the patient ages, RV pressures, aortic blood oxygen saturations and ejection fractions. These findings led us to conclude that: (1) suprasystemic pressure overload of the RV induces macroscopic LV hypertrophy; (2) mild and suprasystemic pressure overload of the RV induces hyperfunctional changes in the LV; (3) myocardial degeneration is not related to hypertrophy nor to hypoxia, but is part of a more widespread cardiovascular fetopathy.

Adolescent↗
PubMed1987

Restrictive cardiomyopathy in children. Ultrastructural findings.

Restrictive cardiomyopathy is usually related to fibrosis of the endocardium or to an infiltrative disorder. However, in few cases, it can be due to isolated pathology of the myocytes but such alterations are not well characterized. This paper reports the disease in two 7 year old patients. There was severe venous congestion and catheterisation revealed increased end diastolic pressure in the ventricles. Both pericardial and myocardial biopsies were performed, as the clinical and haemodynamic data were indistinguishable from constrictive pericarditis. The structure of the pericardium was normal. The endocardium was not thickened. The interstitium of the myocardial tissue was not increased. Electron microscopic examination revealed intracellular masses of disorganized myofilaments. These large deposits may have produced decrease compliance of the myocytes and of the ventricular walls.

Biopsy↗
PubMed1987

[Mitral atresia. Anatomical aspects].

This study is devoted to a series of 30 anatomical cases of mitral atresia. The left atrium was dilated in 5 cases and hypoplastic in 25. The interatrial ostium was small in 50% of the hearts. Left atrio-ventricular concordance was present in 29 cases, as against 1 case of discordance. There was no atrio-ventricular connection in 29 cases, and the mitral valve was imperforate in 1 case. Connections between the tricuspid valve and the main ventricle were normal in 26 hearts. The tricuspid valve straddled the septum in 4 cases. Five hearts had two ventricles, 25 had a single ventricle. Nine hearts showed no ventriculo-atrial atresia. The main vessels were normally located in 1 case, transposed in 2 and originated in the right ventricle in 2 cases; in the 5 hearts with single ventricle the two main vessels arose from the main cavity. Seventeen hearts had an atresic aortic valve and a hypoplastic ascending aorta; the pulmonary artery arose from the right ventricle in 1 case and from the main chamber of a single ventricle heart in 15 cases. The pulmonary valve was atresic and the aorta arose from the main chamber of a single ventricle heart in 4 cases.

Aortic Valve↗
PubMed1987

[Study of myocardial metabolism of NADH by laser fluorimetry during cardiac catheterization].

Laser fluorimetry of reduced nicotinamide-adenine-dinucleotide (NADH) p6 a new technique used for in situ and real-time study of myocardial metabolism. We have evaluated its applicability to clinical situations in 5 patients undergoing haemodynamic exploration. An optic fibre was inserted in a catheter the end of which was positioned in the postero-diaphragmatic part of the left ventricle. The optic fibre was connected to a Cilas-Alcatel fluorimeter. Variations in fluorescence were studied during variations in left ventricular end-diastolic pressure (LVEDP) and during coronary arteriography. An increase in LVEDP resulted in a slight increase in NADH, but when the LVEDP was reduced by a nitroglycerin infusion, NADH fell significantly below baseline values in patients with coronary disease. This effect was most probably due to redistribution of the coronary blood flow from healthy territories to ischaemic territories. In patients without significant coronary stenosis, NADH was not modified by an injection of 10 ml of contrast medium into the right coronary artery. In contrast, in patients with severe stenosis NADH fluorescence significantly increased during the injection, reflecting the ischaemia or myocardial anoxia induced by the contrast medium. NADH laser fluorimetry therefore seems to be promising as a means of exploring myocardial metabolism during cardiac catheterization.

Cardiac Catheterization↗
PubMed1987

[The use of laser fluorometry of NADH in cardiology].

In this paper the first results of experimental studies of myocardial energy metabolism conducted in situ by laser fluorimetry are described. With this method the myocardial oxygen uptake is determined by measuring the fluorescence of NADH (reduced nicotinamide adenine dinucleotide). The equipment required consists of pulsed laser beams in the ultraviolet (337 nm) and visible (586 nm) spectra, very thin catheters with a single optic fibre, and an original digital data processing technique. The first applications envisaged concern: 1. pharmacological studies, notably evaluation of the protective effect of drugs against ischaemia; 2. evaluation of revascularization procedures in emergency surgery, notably assessment of reversibility of the ischaemic lesions; 3. monitoring of myocardial protection during cardiac surgery.

Cardiovascular Agents↗
PubMed1987

Congestive cardiomyopathy and spasm of coronary microvascularisation in man. Electron microscopic evidence.

This paper reports our observations of right ventricular biopsies taken from a 23 year old patient with a congestive cardiomyopathy. The ultrastructural examination of these samples revealed coronary capillary and arteriolar spasms, as well as an ischemic aspect of the myocytes. The responsibility of the coronary microcirculation in the genesis of dilated cardiomyopathies has been suspected for a long time. It has recently been demonstrated in the Syrian hamster, but it has never been clearly evidenced in man. The case that we present seems to confirm this hypothesis. The fact that the spasm is a transitory phenomenon and that it most probably does not involve all areas of the myocardium simultaneously could explain the difficulty encountered in observing this phenomenon in endomyocardial biopsies.

Adult↗
PubMed1987

Intrauterine creation and repair of pulmonary artery stenosis in the fetal lamb. Weight and ultrastructural changes of the ventricles.

Fetal lamb experimental models were employed for intrauterine creation and repair of pulmonary artery stenosis. The study group was composed of 51 fetal lambs including 29 models of pulmonary artery stenosis and 22 control lambs. Gestational age was 89 days at creation of pulmonary artery stenosis. Fourteen fetal lambs (Group A) were studied after creation of the stenosis at 131 days of gestation and compared to normal age-matched control lambs. The systolic right ventricular pressure was significantly higher after creation of pulmonary artery stenosis (76.6 +/- 17.8 versus 50.3 +/- 23.5 mm Hg), but the systolic pulmonary artery pressure was unchanged. The mean right ventricular weight and the mean right ventricular/left ventricular weight ratio were significantly greater after pulmonary artery stenosis than in normal control animals. The transverse myocyte diameter was not modified by pulmonary artery stenosis, but on electron microscopic study the myocytes appeared mature. Ten lambs (Group B) underwent intrauterine repair of pulmonary artery stenosis at 131 days of gestation without cardiopulmonary bypass. The pulmonary artery was clamped and patched. Immediately after repair the right ventricular pressure fell significantly from 85.8 +/- 18.9 to 62.2 +/- 14.6 mm Hg. At birth, 7 +/- 6 days after repair, Group B was compared to Group C (unrepaired pulmonary artery stenosis, five fetuses) and to normal control lambs. The mean right ventricular weight and the mean right ventricular/left ventricular weight ratio were not statistically different in Group B and in the control group. There were no ultrastructural changes after intrauterine repair. We conclude that intrauterine creation of pulmonary artery stenosis causes right ventricular hypertrophy with more mature myocytes. Intrauterine repair of pulmonary artery stenosis is feasible without cardiopulmonary bypass and rapidly abolishes the preponderance of right ventricular weight over left ventricular weight.

Animals↗
PubMed1986

Double outlet right ventricle associated with common atrioventricular canal: report of nine anatomic specimens.

Double outlet right ventricle associated with complete atrioventricular (AV) canal is a rare malformation. Nine cases are reported. In this abnormality the anterior AV leaflet is undivided and free floating and the aortic and pulmonary orifices are in the same frontal plane. In four of the nine cases, the conus was bilateral, but it was slightly hypoplastic in two. In five cases there was no subaortic conus and there was mitral-aortic continuity through the ventricular septal defect. Pulmonary stenosis was present in eight cases. Radiograms may best demonstrate the anatomy of the ventricular septal defect; it extends far anteriorly below the aortic valve, and its inferior rim is deviated by the trabecula septomarginalis.

Heart Defects, Congenital↗
PubMed1986

[Surgical anatomy of the interventricular communications of the septal trabecula].

Muscular ventricular septal defects (VSD) are a special anatomical and surgical entity. They are observed in 85% of cases of multiple VSD. This study was based on the operative findings in 70 patients and 20 pathological specimens of muscular VSD. A surgical topographic classification is proposed, superior, intermediate and inferior, with a specific surgical approach for each of the three types. The superiorly situated muscular VSDs are approached through the right ventricle, the intermediate ones through the right atrium and the inferior through the right atrium or left ventricle. Section of the moderator band greatly facilitates the exposure of the intermediate and inferior segments of the septum through the tricuspid valve. Left ventriculotomies should be reserved for inferiorly situated muscular VSD with right ventricles of small volume.

Heart Septal Defects, Ventricular↗
PubMed1985

[Antenatal cardiac surgery. Creation of an experimental model of pulmonary stenosis in the fetus and repair in utero].

An experimental model of pulmonary stenosis was created in ewes, fetus and repaired before birth by making use of the materno-foetal circulation. Eighteen ewes fetus underwent pulmonary artery banding at an average of 87 +/- 8 days' gestation (normal 135-145 days). All were reoperated before term at 132 +/- 6 days' gestation. They were divided into two groups : group I (7 fetus) was used to evaluate the experimental model of pulmonary stenosis by measuring right ventricular pressures (80 +/- 16 mmHg compared to 58 +/- 10 mmHg in control models), and the increase in right ventricular mass (2.8 +/- 0.5 X 10(-3) g vs 1.9 +/- 0.2 X 10(-3) g), left ventricular mass (2.2 +/- 0.3 X 10(-3) g vs 1.8 +/- 0.4 X 10(-3) g) and septal mass (1.8 +/- 0.3 X 10(-3) g vs 1.3 +/- 0.2 X 10(-3) g). In group II (11 fetus) the pulmonary stenosis was repaired by total clamping and patch repair. After repair and during the days just before birth, the ventricular masses decreased (RV = 2 +/- 0.3 X 10(-3) g; LV = 1.8 +/- 0.4 X 10(-3) g; septum = 1.8 +/- 0.3 X 10(-3) g) approaching values of normal control fetus. This experimental model shows that it is possible to correct cardiac lesions in utero by making use of the materno-fetal circulation and that antenatal repair of an arterial obstruction can rapidly reverse the reactional ventricular hypertrophy.

Animals↗
PubMed1984

[The nucleus of the cardiac myocyte in ventricular hypertrophy. Ultrastructural study].

This study reports the nuclear alterations during ventricular hypertrophy of human heart. The nuclear length is increased while its diameter remains normal. A large spectrum of morphological alterations was observed: increased foldings and convolutions of the membrane; irregular shape of the nuclei, some of them being dumbbell-shaped; intranuclear pseudo-inclusions; intranuclear tubules. These alterations are related to excessive synthesis of membrane during nuclear growth.

Adolescent↗