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Biomedical subjects

F Fontaliran

Publications and source records attributed to F Fontaliran.

At least 55 records · Page 3Linked to original sources
PubMed1991

[Nosologic frontiers of arrhythmogenic dysplasia. Quantitative variations of normal adipose tissue of the right heart ventricle].

The increasing number of arrhythmogenic idiopathic cardiomyopathies with available histological studies by biopsy or peroperative sampling has prompted the need for data about the normal structure of the right ventricle. A retrospective study of right ventricular tissues was undertaken in 148 autopsies. The quantity of adipose tissue was scored 0 (only epicardial fat visible) to 4 (total replacement of the myocardium by adipose tissue). The topography of the adipocytes was also coded 0 to 4 according to the degree of intermyocytic penetration, irrespective of the total quantify of fat. The amount and extension of adipose tissue in the right ventricular wall was striking. Fifty called "normal" appearances with a myocytic wall of normal thickness and a separate layer of epicardial fat, were only present in 61 of the 148 cases. Adipocytes were present in variable numbers, often unexpectedly high in the majority of cases, with no relationship to the age or gender of the patient with frequent individualization of the myocardial bundles. These surprising findings in normal right ventricles should be born in mind when considering the diagnosis of arrhythmogenic right ventricular dysplasia (ARVD). The histopathological appearances of ARVD are very similar but also differ very significantly, at least in typical cases. The adipocytes are often present in large numbers but this is banal and non-specific. On the other hand, the bundles which penetrate the epicardial fat are usually fibro-muscular and not purely myocytic. In addition, arterioles suggesting segmental diversions are present within the fatty layer with non-specific inflammatory cells.(ABSTRACT TRUNCATED AT 250 WORDS)

Adipose Tissue↗
PubMed1990

Preliminary report: follow-up after dynamic cardiomyoplasty.

Five patients were studied 5-13 months after dynamic cardiomyoplasty for refractory heart failure. In two, muscle flap stimulation caused a pronounced increase in cardiac index (mean 55%) and ejection fraction (mean 75%); no patient showed improvement in cardiac filling pressure. 2 years after surgery, one of the patients with haemodynamic improvement died from ventricular fibrillation, and histochemistry of the stimulated muscle flap revealed predominantly fatigue-resistant type I fibres, without evidence of fibrosis. In selected cases, dynamic cardiomyopathy could be of long-term benefit.

Adult↗
PubMed1990

[Congenital and acquired right ventricular dysplasia].

Arrhythmogenic right ventricular dysplasia has been described as a developmental malformation occurring during foetal life. This explains a number of familial cases of this condition where dysplasia was the result of a genetic abnormality transmitted in an autosomal dominant mode with incomplete penetrance. Histological data of peroperative or post-mortem specimens of 27 cases showed a large number of grape-like lymphoplasmocytic infiltrations. These appearances suggest an inflammatory origin of the disease, most probably related to an infective etiology. The authors suggest that in addition to the congenital form there may also be a possibility of acquiring arrhythmogenic right ventricular dysplasia after an episode of myocarditis.

Adult↗
PubMed1990

Absorbable rings for pediatric valvuloplasty. Preliminary study.

Secondary valvular stenosis is a significant risk of annular ring implantation during valvular repair in children. To avoid this problem, we have developed an absorbable prosthetic ring (APR), which induces the generation of a biologic fibroelastic ring with mitotic capability and thereby allows atrioventricular annulus growth with age. Twelve polydioxanone (PDS) biodegradable APRs were surgically implanted in immature goats. To avoid possible embolic complications from ring fragments during the absorption period, APRs were covered with an extensible sewing sheath of high-porosity polyester, allowing contact between the PDS, blood, and endocardium. Four APRs were implanted into the right atrial cavity, four in the tricuspid position, and four in the mitral position. Histological studies at 6 months showed a considerable amount of remaining PDS. At 1 year, only small residual fragments of PDS were present, surrounded by collagen and elastic fibers as well as fibroblasts with mitotic activity. This histological structure represents a new biologic fibroelastic ring, which has originated from PDS rings. Echocardiography at 12 months showed that the elasticity of APRs and fibrotic tissue allows normal systolic and diastolic valve motions. These findings, which demonstrate histological changes in native valve annuli as well as stable and elastic annuloplasty without secondary stenosis in growing animals, call for new studies involving hearts with valvular disease.

Animals↗
PubMed1989

Electrode catheter ablation of resistant ventricular tachycardia in arrhythmogenic right ventricular dysplasia: experience of 13 patients with a mean follow-up of 45 months.

Electrode catheter ablation (fulguration) is a new technique for the treatment of ventricular tachycardia resistant to medical treatment. It proved effective in our hands in a series of 65 cases of ventricular tachycardia of varied origin. This paper reports the early results in a subgroup of 13 patients suffering from arrhythmogenic right ventricular dysplasia in whom shocks ranging from 160 to 280J, single or multiple, in one or up to three sessions were delivered. In the 11 patients surviving the DC ablation procedure single or multiple monomorphic sustained VT was brought under control. However, four patients (36%) required therapeutic antiarrhythmic treatment following the fulguration therapy. During the learning phase one case of death was related to poor catheter selection and the other to poor protocol. The post-mortem study of the effect of shocks depends on the anatomical structure to which the shocks have been delivered.

Adult↗
PubMed1989

[Congenital atrioventricular block and maternal lupus erythematosus. Histologic discovery of tumor of the atrioventricular node].

A case of congenital atrioventricular block in a newborn whose mother presented with systemic lupus erythematosus (SLE) is reported. Despite intensive care the child died a few hours after birth. Serial sections of the heart could be examined. Histology provided information on the appearance and distribution of the lesions. In particular, the sinus node was small for the child's age, and its supplying artery was found to have a hyperplastic media with adventitial sclerosis; the interatrial and interventricular septa showed subendocardial fibrosis invading the adjacent myocardium. Owing to the scarcity of systematic histopathological examinations, such lesions have seldom been described. In addition, a tumour of the atrioventricular node, known as mesothelioma or hemolymphangioma, was discovered. This case is exceptional in that histopathological findings similar to those described in SLE, though rarely as numerous, were associated with a very rare tumour never hitherto described in such a young patient. The relationship between the two categories of lesions is discussed.

Adult↗
PubMed1989

[Causes of sudden death in athletes].

Sudden death is rare in athletes, and it is only in recent years that significant series were collected, making it possible to draw the cardiological profile of athletes who died suddenly at the peak of exertion or while recovering. A study of the literature, both medical and paramedical, has yielded 53 cases in which the most frequent causes of sudden death were hypertrophic cardiomyopathy (26 p. 100), (arrhythmogenic right ventricular disease (19 p. 100), congenital abnormalities of coronary arteries (11 p. 100) and coronary atheromatous lesions (9 p. 100), to which must be added various other causes. This study clearly demonstrates the hitherto unrecognized importance of arrhythmogenic right ventricular dysplasia-a condition which, as recent data suggest, is not solely due to a myocardial development disorder but also to an infective disease, an acute of chronic myocarditis. In subjects with this condition, new exploratory methods might detect the presence of an arrhythmogenic substrate during medical screening of athletes, but in any case these causes of sudden death suggest that a fast rhythm disorder was involved in several of these deaths. This disorder could be treated if the attendants were trained to carry out cardiorespiratory resuscitation procedures or if they had access to a defibrillator which should be available on every sports field.

Adult↗
PubMed1988

[Morphologic study of cardiac cells in sheep before and after electric shock].

A combined electrophysiological and histopathological study was conducted on sheep myocardium fragments rich in easily identifiable conduction cells subjected to electric shocks of varying intensity. Tissue fragments were immersed in a thermostatically-controlled bath at 37 degrees C, perfused with a carbonated standard tyrode solution at the rate of 30 ml/min and stimulated at a constant bipolar 1 C/sec tension twice as high as the threshold of diastolic excitability. After measurement of reference values, electric shocks of 2 to 80 joules were delivered between two electrodes placed on both sides of the tissue fragment. The electrophysiological part of the study showed disorders of conduction which, depending on the energy delivered, were more or less complete and reversible. The histopathological part of the study showed that conduction tissue was extremely fragile, even to low-energy shocks. This fragility was in glaring contrast with the relatively modest damage suffered by myocytes. Liquefaction and/or coagulation of Purkinje's cells was also striking, as it extended over an area much wider than that subjected to the shock. Thus, with medium intensity shocks destroyed conduction bundles were seen to creep between myocytes that often were perfectly normal or showed rare hypercontraction bands. Some myocytes were in the process of degeneration or even eosinophilic necrosis, but except in case of violent shock these were more or less isolated elements in the vicinity of the stimulated area. The fragility of conduction tissue and its selective damage by low-intensity shocks may be explained partly by its low impedance which allows preferential passage of the electric current.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

[Cellular electrophysiological and histopathological study of the effects of continuous electric current on the sheep heart].

The energy released in electrode catheter ablation is spent on thermal, mechanical and electrical effects. The relative importance of these effects and their role in the adverse reactions of the method are controversial. Low-energy shocks have been shown to modify cellular electrophysiological and histopathological parameters in the sheep heart. The purpose of this study was to individualized the effects of the electric current itself, using an isolated electrode to suppress barotrauma and reduce the amount of energy delivered. Three fragments of epicardium, seven false tendons and eight loop-shaped strips were placed in an electrophysiology bath perfused with Tyrode's solution and subjected to an electric field induced by an 18 V battery without discharge from a condenser, so that all mechanical effects were suppressed. The electric field was supplied via an isolated electrode, thus preventing the current from leaking through the Tyrode's solution and forcing it across the fragments studied. The electrophysiological parameters were studied by the microelectrode method on both sides of the area subjected to the electric field. This was followed by a histological study. The current intensity was 15 mAmp, and the energy delivered in one second was 270 mJ. Membrane depolarization was constant, and no automatic of post-depolarization activity was observed after the electric current was applied. The two-dimensional conduction accounted for the absence of block in the epicardial fragments. In the false tendons a conduction block constantly appeared between the two electrodes, associated with a decrease in conduction velocity in the recovery phase (2.1 +/- 0.24 vs 1.8 +/- 0.23 m/s, p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Effect of latissimus dorsi dynamic cardiomyoplasty on ventricular function.

In our approach to dynamic cardiomyoplasty, which consists of wrapping a skeletal muscle around the heart and stimulating the former in synchrony with heart contractions to augment ventricular contractility, we have transferred a latissimus dorsi muscle flap to the heart by way of a partial resection of the second rib and subsequently suturing the muscle flap around the ventricles. The muscle flap is stimulated by a Cardio-Myostimulator burst-pulse generator (Medtronic SP 1005) connected to intramuscular electrodes. In preclinical animal research, the latissimus dorsi muscle flap was shown to maintain adequate contractile force and to increase its fatigue resistance by gradual conversion of glycolytic-fatigue-sensitive-to-oxidative-fatigue-resistant muscular fibers (100%). Histochemical and biochemical studies of chronically stimulated muscles showed a total transformation of muscle fast myosin to slow myosin with characteristics similar to those of myocardium. Electron microscopy showed preserved myofibrillar cytoarchitecture and increased mitochondrial density in the cell. At 9 months, cardiac output and ultrasonic Doppler studies showed a significant increase in ventricular function (cardiac output, +21%; peak blood velocity, +40% -80%; and stroke volume, +98% -102%) during muscle stimulation. In the clinical situation, long-term (range of follow-up interval, 4-42 months) beneficial cardiac effects of cardiomyoplasty have been documented in eight patients with various pathologies (ventricular tumor, left ventricular aneurysm, ischemic disease, and dilated cardiomyopathy). Our current understanding of this process is that dynamic cardiomyoplasty acts in two ways: 1) it promotes more vigorous systolic contraction, and 2) it appears to limit heart dilatation.

Animals↗
PubMed1987

[Cellular effects of electric shock. Definitions, physical principles, cellular electrophysiology and morphological analysis of the shocked areas].

In this experimental study the electrophysiological changes induced by electric discharges such as used clinically in some arrhythmias refractory to the usual treatments were investigated. With energies comprised between 2 and 80 joules profound modifications of the electrophysiological properties of muscle cells and conduction were observed. These modifications included loss of resting potential, inactivation of the fast sodium flux, increase in refractory periods of conduction and disorders of conduction through the shocked areas with, at most, complete block sometimes reversible when low-energy currents were used. With the same amounts of energy these effects were maximal when the current traversed tissues positioned between the electrodes and decreased in all other cases. Usually, with currents of 10 joules or more all electric activity ceased in a radius of about one centimetre around the shocked area.

Animals↗
PubMed1987

[Cellular electrophysiological effects of fulguration by low energy shock].

In spite of the increasing use of catheter ablation in the treatment of refractory ventricular and supraventricular arrhythmias, little information is available on the basic electrophysiological effects of the treatment. Although high-energy shocks are still usually delivered, the current trend is toward lower energies. We studied the electrophysiological effects of non-deflagrating anodic shocks of 2 joules on preparations of sheep ventricular myocardium and Purkinje's fibers. The shocks were delivered by a standard defibrillator between a small-area catheter electrode and a wide-area inert electrode. Action potentials were recorded by the standard microelectrode technique. After the shocks were delivered, the Purkinje's cells that were 5 mm distant from the shocked area on either side were depolarized in the -30 to -40 mV zone, but they progressively reverted to an almost normal resting potential. Recovery was bi-exponential, with time constants of about 1 min and 10 min respectively. Similarly, the conduction block induced by the electric shock in 100% of the cases was reversible in 50%. It must be noted that at the time of conduction recovery the pattern observed was that of electrotonic conduction where the distal action potential conducted was preceded by a pre-potential. This pattern always regressed progressively, with gradual disappearance of the pre-potential in the distal cells, suggesting that the unexcitable area had vanished or become smaller. Although a normal 1/1 conduction and normal action potentials returned in the cells that were 5 mm distant from the shocked area, recordings performed at a distance of 1 to 4 mm from that area disclosed alterations of action potentials that were usually irreversible.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗
PubMed1987

[Lesions of coronary atherosclerosis in drug users. Preliminary studies].

A study of hearts removed during medicolegal autopsy of drug addicts after their sudden death demonstrated the constant presence of coronary lesions very similar to common atherosclerosis but remarkable by their magnitude, especially in patients dying at an age when atheromatous disease is relatively rare. Coronary circulation was studied in 10 cases by histoenzymatic, immunologic, histologic and ultrastructural examination of fresh and fixed tissues. The parietal thickening, noted in all cases to variable degrees, had provoked stenosis in several cases, preferentially in the proximal portion of the anterior interventricular vessel. On light and ultrastructural microscopy, the lesions observed were similar to atherosclerotic lesions, but differed in several respects and notably the absence of antiglobulin and the lack of increase of glycosaminoglycans. Although the relations between the drug and atheroma are undeniable, their mechanism is at present unknown.

Adolescent↗
PubMed1986

Risk and consequence of infection at the site of microsurgical repair: an experimental model.

The consequences of postoperative infection at the site of microsurgical repair were studied. The experiment used 60 Wistar rats which were divided into 3 groups of 20 each. The femoral artery, vein, and nerve were transected unilaterally and repaired using microsurgical techniques. Staphylococcus aureus was then inoculated into the wound of group 1. Beta-hemolytic Streptococcus was inoculated into the wound of group 2. Group 3 rats served as controls. Clinical, anatomical, bacteriological and histopathological examinations were performed on postoperative days 8 and 30. Wounds in which S. aureus was inoculated demonstrated a significant tendency toward vascular thrombosis with extensive tissue destruction. In the majority of these cases, the necrosis caused by the primary infection engendered an associated, opportunistic infection. Streptococcal inoculations in group 2 demonstrated less severe changes than in group 1. These changes were characterized by injury of the vascular structures themselves with a significant tendency for thickening of the arterial wall, perivascular inflammation, and hematoma formation at the site of the repair. This model allows demonstration of the enzymatic and toxic consequences of bacterial infection in a postoperative site characterized by cellular destruction and interstitial edema surrounding foreign bodies represented by sutures.

Animals↗
PubMed1986

[Presence of immunoglobulins and complement in the walls of the coronary arteries in atherosclerosis].

A histopathological and histoimmunological comparison was performed on 143 fragments on coronary arteries taken from 43 patients who died of ischemic heart disease and from 20 patients who died of other diseases. The immunological study research of Ig (A, G, M) and C3 fraction of complement in the 3 coronary layers was done by the immuno-peroxidase technique. The fixation was essentially observed in fibromyocytes. A good correlation existed between atherosclerosis lesions and fixation of Ig and C3 fraction of complement in both the media and the intima. On the other hand, this correlation was not observed in the adventitia. Accumulation of immunoglobulins and of the C3 fraction of complement in atherosclerosis seemed specific and proportional to the degree of arterial well lesion. The significance and the role of this accumulation remains to be studied. It may be hypothesized that Ig and complement fixation on fibromyocyte cell receptors or on the fibrous tissue fundamental substance is followed by the formation of antigen-antibody complexes, which act as foreign bodies which are either responsible for (or a reflection) of the onset of lesions or, at least, of their increasing severity or their persistence.

Complement C3↗