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Biomedical subjects

H Bricaud

Publications and source records attributed to H Bricaud.

At least 145 records · Page 8Linked to original sources
PubMed1978

[Isolated left anterior hemiblock during attacks of angina pectoris].

The clinical significance and mechanism for changes in the axis of the QRS complex during attacks of angina pectoris (excluding cases of Prinzmetal's angina) are unknown. Previous work has suggested that left anterior hemiblock under these circumstances is a sign of unstable angina indicating a lesion in the anterior descending artery. Two cases with left anterior hemiblock associated with frequent attacks of angina have been the subject of careful study. In case one, atrial stimulation tests showed that the left axis deviation was not related to tachycardia. It only occurred when atrial stimulation was carried out for long enough to induce myocardial ischaemia as witnessed by precordial pain and disorders of repolarisation. In case two, the left anterior hemiblock came on at first at the same time as the attacks of angina, and then became permanent. Bypass graft of the anterior descending artery restored the QRS axis to normal, and corrected the repolarisation disorders which were of ischaemic origin. These findings argue in favour of an ischaemic origin of this conduction defect. Unlike ischaemia of the left anterosuperior subbranch, anterior left hemiblock is indicative of extensive ischaemia of the anterior wall of the left ventricle relative to an obstruction in the anterior descending artery or in the main trunk of the left coronary artery.

Aged↗
PubMed1978

[Hemolysis and platelet function in patients with prosthetic heart valves. Changes during exercise and with propranolol].

10 control subjects and 27 patients with prosthetic valves (15 with Björk aortic valves, 6 with mitral prostheses, 4 with aortic and mitral valves, 1 with a Björk mitral and a Starr aortic valve, and 1 with a Beall mitral valve) underwent, at intervals of 24 hours, two maximal exercise tests, initially without (day J) and subsequently with (day J + 2) propranolol in a dose of 80 mg/24 h, haemolysis and platelet function being assessed immediately before and immediately after each test. Exercise tolerance was not altered by propranolol in this dose, provided the heart size was not more than 1500 ml. Haemolysis, as assessed by the level of lactic dehydrogenase (LDH1) was increased by exercise, especially in the aortic prosthesis cases in which the LDH1 was increased by 21.6% (p less than 0.025). The increase was less marked under propranolol treatment, when it was 12.3% (p less than 0.05). Propranolol did not correct the platelet clumping caused by the prosthetic mitral valves, but did decrease platelet stickiness on exercise in the patients with prostheses (delta = -11.7%; p less than 0.05). Propranolol can not therefore be recommended for increased haemolysis if there is no demonstrable dysfunction of the prosthetic valve. Neither would we advise its use at present with the aim of reducing thrombotic accidents.

Adult↗
PubMed1978

[Hypertensive cardiopathy. Study of cardiac performance].

Twenty-two hypertensive patients with normal coronary arteriograms underwent a complete study of left ventricular performance. The patients were classified into three groups according to the findings on X-ray and ECG investigation: group I--ECG normal, X-ray normal (6 cases); group II--ECG showed left atrial hypertrophy, X-ray normal (7 cases); group III-ECG showed left ventricular hypertrophy, X-ray showed cardiac dilatation (9 cases). The results of this study were as follows:--cardiac ouptut was lowered in groups II and III;--end-diastolic volume was lowered in group II and raised in group III;--LVEDP was raised in groups II and III;--V max and VEC max were lower in groups II and III than in group I;--left ventricular compliance was diminished in groups I and II. Myocardial rigidity of the left ventricle was similar in the three groups. Hypertensive heart disease is therefore characterised by early changes in compliance of the left ventricle. These are associated with geometrical changes in the ventricle: disturbance of the volume/mass ratio of the left ventricle. These findings have therapeutic implications for the importance of beta-blockers.

Adult↗
PubMed1977

Fibrous long spacing collagen in aortic explants of normal rabbit cultured in hypercholesterolemic serum.

Aortic tissues consisting of all three tunics were removed from normal adult rabbits and cultured in a semisynthetic gelosed medium supplemented by 10% serum obtained either from normal or hypercholesterolemic rabbits. Fibrillar cross-striated aggregates appeared with a high frequency (50%) in the extracellular space of explants cultured from four to eight days in medium supplemented by serum from hypercholesterolemic rabbits, but did not appear in explants cultured in serum from control animals (3%). The electron-dense segment was ruthenium red positive and digested by testicular hyaluronidase. The electron-lucent segment, composed of ruthenium red negative thin filaments, was not modified after hyaluronidase treatment but was strongly digested after collagenase treatment. It is believed that this material was fibrous long spacing collagen synthetized under culture conditions, as shown after tritiated proline incorporation.

Animals↗
PubMed1977

Effects of hypercholesterolaemic serum on aortic explants from normal rats.

Aortic explants obtained from normal adult rats and composed of all 3 tunics were cultured in a semi-synthetic gelosed medium supplemented by 10% serum. Explants cultured with normocholesterolaemic serum kept their in vivo characteristics for more than 12 days at electron microscope and histometabolic levels. However, explants showed considerable differences when cultured in a medium with hypercholesterolaemic serum. Cell proliferation in the tunica media and enhanced synthesis of macromolecular components of the extracellular matrix were observed. These laterations occurring inside the explants, which had kept all their tissular relationships, suggest that this culture system may be valuable for further studies on atherosclerotic processes.

Animals↗
PubMed1977

[Hemodynamic effects of intravenous amiodarone in humans].

The haemodynamic action of I-V Cordarone have been studied in 20 subjects over a 15 minute period. Over the 15 minute period we studied variations in left pulmonary and ventricular pressures, in cardiac output, and in the paramaters of contraction VEC max, V max and Taylor's index. At a dose of 5 mg/kg there is a fall in peripheral resistance (1274 +/- 232 to 915 dynes/s/cm-5), and the measurements of contraction hardly vary. At a dose of 10 mg/kg, after an initial increase in output and a fall in peripheral resistance there occurs, after 4 minutes, an increase in left ventricular end-diastolic pressure (from 6 +/- 2 to 13 +/- 4 mmHg, P less than 0.01), and a lowering of contractility (VEC max reduced from 49.7 +/- 12.4 to 27.1 +/- 3.8, P less than 0.001). We have shown that the first phase of this response is due to the solvent (Tween 80), while the fall in contractility is due to the amiodarone. Doses above 10 mg/kg must be used with care, and only if there is no evidence of impaired cardiac function.

Amiodarone↗
PubMed1976

[Influence of a lathyric agent and of hypercholesterolemic serum on cell cultures of fetal rabbit aorta].

Cell cultures of foetal rabbit aorta are cultivated with a lathyric agent (beta-amino-propio-nitrile) or with an hypercholesterolemic serum; if morphological features, in these two cases, correspond with modifications observed, in vivo, when adult rabbits are respectively submitted to the same treatment, enzymatic activities of collagen metabolism vary in opposite way. Therefore, the influence of different parameters to be studied on vascular cell functions become easier.

Aminopropionitrile↗
PubMed1976

[Study of the extracellular macromolecular meshwork elaborated by rat aortic cells in secondary culture].

Rat aortic smooth muscle cells isolated by digestion of the vessels by elastase and trypsin and grown in subculture, are examinated by phase, optic and electron microscopy for their ability to synthesize connective tissue components. Large amounts of extracellular material accumulates within the spaces between the cell; it consists of amorphous substance identified histochemically as elastin, of 110 A microfibrils and of periodic fibrils (430-490 A); the chemical nature of these two last components is discussed.

Animals↗
PubMed1976

Galactosyl transferase assay. Application to experimental atherosclerosis.

To establish a repetitive measurement, aortic galactosyl transferase activity has been studied with a specific exogenous acceptor, collagen. Reactions were realized with an acellular biosynthesis mixture containing, collagen (3-4 mg/ml) an aliquot of enzymatic extract preparation (105000 g supernatant (2-3 mg/ml of proteins), UDP (14C) galactose (300 pM/ml). Galactose incorporation into collagen required Mn++ (2.5. 10-3M), incubation temperature of 37 degrees C and pH =7,75. Under such conditions a reproducible assay of aortic collagen galactosyl transferase was possible. After submitting rabbits to a chronic lathyric intoxication and/or to an hypercholesterolimic diet, galactosyl transferase activity was measured in rabbit aortic wall. Enzymatic activity was increased for rabbits under treatment, and the increase was directly proportional to the length of treatment (BAPN associated with cholesterolemic diet).

Aminopropionitrile↗
PubMed1976

[Ultrastructural study of 11 cases of obstructive myocardiography of the left ventricle].

A fragment of septum was removed for biopsy in 11 patients with obstructive cardiomyopathy who were undergoing surgery. Electron microscopi revealed an increase in the numbers of mitochondria, deposits of glycogen, and deforming fibrosis. As far as the components of muscle fibres are concerned, both lysis and synthesis of neosarcomeres are to be found, together with abnormalities of the Z band and disorientation of the myofibrils. The number and severity of these abnormalities were found to vary from patient to patient and also in different sections. Although these features are virtually constant in cases of obstructive cardiomyopathy, they are not specific for this condition; they are also found in cases of non-obstructive hypertrophic cardiomyopathy.

Cardiomyopathy, Hypertrophic↗
PubMed1976

[Reintervention after valve replacement surgery. Study of 358 cases].

There is still a place for conservative surgery in valvular disease of the heart to the extent that artificial prostheses have not yet been perfected sufficiently for them to be regarded as the method of choice. While these conservative operations are rarely applicable to the aortic valve, techniques such as Carpentier's ring occupy an important place in the treatment armamentarium for disorders of the mitral valve, and even more so of the tricuspid valve.

Aortic Valve↗
PubMed1976

[Valve protheses and anti-vitamin K. Biological study in patients given weak and strong doses of anticoagulants].

57 patients with Björk aortic valves had an in-depth study of their coagulation carried out. It seems that the well-anticoagulated group (39 patients) had more marked haemolysis, had a higher mean level of fibrinogen and PDF, but less biological signs of activation of fibrinolysis than the group who were non- or mildly-anticoagulated (18 patients). The increased platelet aggregation, which is often noted, was correlated with the signs of haemolysis, or of activation of the breakdown of fibrinogen. Apart from the problem of haemolysis, anticoagulant treatment appears biologically to be a moderating factor in the activation of the breakdown of fibrinogen and, by this means, of the utilisation of clotting factors.

Anticoagulants↗
PubMed1976

[Performance of the lift ventricle in left ventricular obstructive cardiomyopathy].

A retrospective study of 100 cases of obstructive cardiomyopathy of the left ventricle has allowed us to predict a mean survival of 30 years after the murmur has been discovered. A comparative angiographic and haemodynamic study was carried out on 50 cases using the NYHA classification into four functional stages. The lowering of functional status, at rest, seems to occur: -With the advent of a permanent intraventicular gradient (6 +/- 5 mmHg in stage 56 +/- 38 mmHh in stages III and IV, p less than 0.001). Despite preservation of the indices of contractility (VECmax 1.81 +/- 0.66 c/s at stage I, 1.71 +/- 0.7 C/S at stages III and IV). -With a progressive change in the ventricular complicance (dV/dP/VTD 0.029 +/- 0.016 at stage I, 0.017 +/- 0.01 at stage III and IV). A progressive change in venticular complicance seems to be secondary to an increase in the parietal diastolic thickness and to lesions visible histologically. It governs the natural history of the condition and the results of surgical treatment.

Adolescent↗
PubMed1976

[Influence of acute exertion and physical training on platelet function of the coronary patient].

The platelet function, fibrinogen level, and the various lipid fractions were studied in 17 coronary patients before, during and after a maximal effort, both before and after a three month period of physical training. Exercise capacity increased by 26%, stickiness went down by 27% at rest (p less than 0.025) and 42% on exercise (p less than 005), and aggregation varied (according to the method used) between 24%, 25% and 2% at rest (p less than 0.001) and 36%, 43% and 32% on exercise (p less than 0.001); the levels of fibrinogen and the lipid fraction remained unchanged. A patient whose exercise capacity was not increased by training had no alteration in platelet aggregation. According to this small series, physical training has an effect similar to that of acetyl salicyclic acid. The possible significance of these results is discussed.

Adenosine Diphosphate↗
PubMed1976

[Ventricular tachycardia of the infant. 2 new cases].

Two new cases of ventricular tachycardia (VT) in the infant are reported, and reviewed in the light of the 23 case histories found in the literature. The diagnosis rests upon eliminating a pre-excitation syndrome, which is so common in this age group. The VTs found in infants are rapid, irregular, and take many different forms. They often necessitate urgent treatment with electric shocks. Preventive treatment consists of a combination of procainamide and beta-blockers in relatively large doses. The search for an aetiological agent should include a haemodynamic and angiocardiographic study of all the chambers of the heart to exclude cardiomyopathy, tumours, papyraceous right ventricle and congenital heart defects. Where no cause can be demonstrated, preventive treatment should be given, with regular electrical testing and other follow-up investigations. An attempt to reduce the drug dosage should be made every 6 months, in hospital. In cases which prove resistant despite adequate treatment, it seems justifiable to carry out a pericardial exploration with the aim of diathermising the ectopic focus; this approach is suggested because of the poor natural history of this type of case.

Electrocardiography↗