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Biomedical subjects

D Duboc

Publications and source records attributed to D Duboc.

89 records · Page 5Linked to original sources
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

Phosphorus NMR spectroscopy study of muscular enzyme deficiencies involving glycogenolysis and glycolysis.

We used phosphorus NMR spectroscopy to study 16 patients with muscular enzyme deficiencies affecting glycogenolysis and glycolysis. Study of phosphomonoester (Pm) kinetics and intracellular pH during exercise and recovery provided criteria for the distinction of these metabolic myopathies by NMR spectroscopy. The Pm peak was undetectable in patients lacking debrancher enzyme or phosphorylase. By contrast, in phosphofructokinase (PFK) or phosphoglycerate kinase (PGK) deficiency, the Pm peak was larger than that of inorganic phosphate in exercise, whereas it was always smaller in normal subjects. During recovery, the disappearance of Pm was slower in PGK than in PFK deficiency.

Adolescent↗
PubMed1987

[The value of NMR spectroscopy in the study of myocardial ischemia and in cardiovascular pharmacology].

Nuclear magnetic resonance spectroscopy is a non-destructive method used to investigate the intracellular repercussions of experimental myocardial ischaemia. The effectiveness of drugs or cardioplegic agents in preserving myocardial metabolism during and immediately after ischaemia can be tested on various models. The results obtained in different experiments and the metabolic studies conducted in patients treated with cardiotropic drugs illustrate the value of this method in cardiovascular pharmacology.

Adrenergic beta-Antagonists↗
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

[Incomplete spontaneous rupture of the supravalvular aorta complicated by pericarditis and aortic insufficiency].

The natural history of an incomplete spontaneous rupture of the ascending aorta over a 4-year period is reported. The initial presentation was subacute pericarditis which regressed spontaneously. Aortic regurgitation developed on the 100th day of the disease and was perfectly well tolerated haemodynamically for 4 years. This favourable course was interrupted by type I aortic dissection. The post-mortem examination provided an explanation for the peculiar development and course of the aortic regurgitation: it was due not to the usual prolapse of the cups but to displacement of the left posterior commissure by the retractile fibrosis arising from the lower lip of the spontaneous rupture.

Aged↗
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↗
PubMedDate not supplied

Non-invasive evaluation of the cardiac function in golden retriever dogs by radionuclide angiography.

Golden Retriever dogs manifest an X-linked, Duchenne-like, muscular dystrophy with a characteristic lack of dystrophin. Histologic findings have demonstrated the cardiac involvement in these dogs to be a model for the cardiac insufficiency in human Duchenne muscular dystrophy (DMD). The goal of this study was to assess the capability of radionuclide angiography (RNA) as an assessment tool to measure the ventricular dysfunction in these dogs. Three dogs, one normal and two with muscular dystrophy (MD), were studied by equilibrium gated blood pool. Red blood cells were labelled with 420 MBq of 99mTc. The three dogs lying on their left sides on the table, received no drugs and were not restrained in any manner. RNA left ejection fraction (EF) and echographic measurements of left ventricular fractional shortening (FS) were performed during the same session. EF values were 61%, 48%, 36% and FS values were 47%, 32%, 26%, respectively, for the control dog, the 6 month old MD dog and the 12 month old MD dog. This preliminary study demonstrates the potential usefulness of RNA for the non-invasive follow-up exams of specific therapy in a canine model of muscular dystrophy.

Animals↗
PubMedDate not supplied

[Stenosis of the main trunk of the left coronary artery. Apropos of 54 cases].

In the 54 patients studied coronary arteriography alone showed stenosis of the left main coronary artery (a lesion observed in 5.2 p. 100 of pathological coronary arteriographies), associated with other coronary lesions, 72.2 p. 100 of which involved all three major vessels. Ventriculography was abnormal in 53 p. 100 of the cases, with a less than 45 p. 100 left ventricular ejection fraction in 37.4 p. 100 of them. Nine patients were considered inoperable; 4 of these died during a 40-month follow-up period under medical treatment. Forty-five patients underwent coronary bypass; there were 4 peri-operative deaths (8.9 p. 100), 8 post-operative myocardial infarctions (17.8 p. 100) and one late death (2.2 p. 100). These patients were followed up for a mean period of 26.4 months. All authors who have studied the subject agree that surgery is beneficial: not only does it improve cardiac function, but it also prolongs survival. In spite of the peri-operative risks, surgery must be contemplated in patients with a more than 50 p. 100 stenosis of the left main coronary artery, provided the cardiac vascular bed is accessible to revascularization.

Arteriosclerosis↗
PubMedDate not supplied

[Exercise intolerance caused by muscular phosphorylase kinase deficiency. Contribution of in vivo metabolic studies].

A 33 year old man has been presenting since childhood an exertional muscle pain syndrome without myoglobinuria. Muscle biopsy revealed a vacuolar myopathy with glycogen excess in subsarcolemmal and intermyofibrillar spaces which was confirmed by electron microscopy. Plasma production of ammonia was abnormally high during exercise on a bicycle ergometer while the raise of lactate was normal. NMR spectroscopy showed an increased muscle glycogen content, with a slight and delayed drop of the pH during exercise. Phosphorylase b kinase activity was undetectable in muscle specimen whereas activities of others enzymes of carbohydrate metabolism were normal. Clinical presentation of our patient is compared to that of the reported cases of phosphorylase b kinase deficiency.

Adult↗