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Biomedical subjects

J Bardet

Publications and source records attributed to J Bardet.

At least 19 recordsLinked to original sources

Clinical aspects of mitochondrial disorders.

Mitochondrial disorders have long been regarded as neuromuscular diseases only. In fact, owing to the ubiquitous nature of the oxidative phosphorylation, a broad spectrum of clinical features should be expected in mitochondrial disorders. Here, we present eight puzzling observations which give support to the view that a disorder of oxidative phosphorylation can give rise to any symptom in any organ or tissue with any apparent mode of inheritance. Consequently, we suggest giving consideration to the diagnosis of a mitochondrial disorder when dealing with an unexplained association of symptoms, with an early onset and a rapidly progressive course involving seemingly unrelated organs. Determination of lactate/pyruvate and ketone body molar ratios in plasma can help to select patients at risk for this condition.

Child, Preschool

Hemodynamic evaluation of heterotopic heart transplantation.

To assess the relative contribution of native and donor hearts to total circulatory performance after heterotopic transplantation, we used cardiac catheterization to examine 10 patients. Left and right ventricular filling pressures significantly decreased by 41% and 36%, respectively, cardiac index increased by 25%, and pulmonary arteriolar resistance was reduced by 61%. Patients were subdivided into two groups according to the presence of one (group I) or two (group II) peaks on the aortic pressure curve. In group I, the donor left ventricle assumed total left ventricular work and 80% of right ventricular work. Because the native left ventricle could not generate enough pressure to open the aortic valve, its entire stroke volume was ejected into the common left atrium. In addition, in all four patients a native aortic regurgitation occurred in diastole and systole. In contrast, in group II, native left ventricular systolic pressure always exceeded aortic diastolic pressure. The donor left ventricle contributed 68% to systemic blood flow and the donor right ventricle 51% to pulmonary blood flow. Mild native aortic regurgitation was demonstrated in two patients only. Native left ventricular function deteriorated postoperatively in all patients (ejection fraction decreased from 0.22 +/- 0.09 to 0.14 +/- 0.08), but this deterioration was more marked in group I. Postoperative depression of native left ventricular function could not be ascribed to progression of coronary artery disease but was mainly due to reduced preload (competitive filling) and increased afterload. Thus in group I patients with more severe preoperative left ventricular dysfunction, the donor heart behaved like a total biventricular assist device. In contrast, in group II patients the donor heart acted like a partial biventricular assist device.

Cardiac Catheterization

[Hyperlysinemia and hyperammonemia].

A quite important increase of plasma lysine was often reported in different cases of hyperammonemia. This retrospective study of patients with different types of hyperammonemia shows that hyperlysinemia is not automatically associated to hyperammonemia (lysinemia is expressed as the percent of total aminoacidemia). Hyperlysinemia was observed with neonatal propionic and methylmalonic acidurias. Reye's syndrome and to a less extent with ornithine transcarbamylase deficiency.

Ammonia

[Methodological errors in amino acid assay in biological fluids].

Numerous methodological errors have been observed in the measurement of free-amino acids in the biological fluids. Some of them are related to the presence or the formation of amino acids or ninhydrin-positive compounds in tubes or anticoagulants used for the blood sampling. Hemolysis or blood clotting modify the concentration of some amino acids in plasma. A special error observed with the capillary blood is related to the amino acids present on area of the skin. Bacterial contamination of urines or buffers used for the analysis can also modify the results of the amino acids assays.

Amino Acids

Early alterations of plasma free amino acids in chronic renal failure.

In order to assess the influence of renal failure and nutritional status on the fasting concentrations of free plasma amino acids, we studied 81 ambulatory adult patients with varying degrees of chronic renal failure. Each of the patients was in good general and nutritional condition. Compared to 33 healthy controls, patients with mild renal failure (Ccr greater than 25 ml/mn) exhibited significantly (p less than 0.01, Student's t test) raised concentrations of cystine, citrulline, ornithine, taurine and 3-methyl-histidine and low level of serine. Concentrations of cystine, citrulline, and 3-methyl-histidine in plasma but not of taurine or ornithine rose in parallel with the progression of renal failure. A significant, but moderate decrease in valine, leucine and isoleucine concentrations was observed in patients with the most marked degree of renal failure (Ccr less than 10 ml/mn). We conclude that changes in the plasma concentration of several non essential amino acids are already present in the early stage of renal failure in patients with no sign of protein malnutrition: these may result from altered metabolic pathways of amino acids related to uremia and/or nephron loss per se whereas the moderate decrease in branched-chain amino acids that is observed only in the advanced stage of renal failure may be, at least in part, nutritional in origin.

Adult

[Cri-du-chat disease: plasma and urinary amino acids].

Ten cases of cri du chat disease due to a del(5)(p14p15) were observed. A highly significant excess of the plasmatic and urinary relative amount of asparagine + aspartate was detected. A highly significant excess of the relative amount of histidine was also noted in the urine but not in the plasma. Excess of asparagine + aspartate could be related to a disorder of purine metabolism. The urinary excess of histidine could be related to a disorder of the aminoacid catabolism.

Adolescent

Variability and reproducibility of quantitative left ventricular angiography.

To evaluate the reproducibility of left ventricular angiography for the assessment of left ventricular (LV) function and regional wall motion, two ventriculographies were performed in the 30 degrees right anterior oblique (RAO) projection, at 15-minute intervals, in 19 patients undergoing coronary angiography. Heart rate, left ventricular systolic pressure, and end-diastolic pressure were measured 15 minutes after the first angiography returned to the baseline values (71.0 +/- 14.1 vs. 72.2 +/- 15.5 beats/minute, 153.6 +/- 18.0 vs. 152.8 +/- 19.9 mm Hg, 21.7 +/- 8.6 vs. 20.9 +/- 7.3 mm Hg, respectively). Global and regional LV performance was analyzed by two observers with a computer-assisted technique. Intraobserver mean variation of end-diastolic volume and ejection fraction was less than 3% of the control value. Interobserver mean variations for the same parameters were less than 4% of control values. For both observers, there was no significant variation of LV end-diastolic volume and ejection fraction from one study to the other. Under stable hemodynamic conditions, the mean observed variations were, depending on the observer, 5-6% of the control value for LV end-diastolic volume and 5% for ejection fraction. Analysis of segmental wall motion was also highly reproducible. The mean intraobserver variation (% of control value) of wall motion ranged from 4.4% to 9.2%, depending on the sectors studied. The mean interobserver variation, whatever the sector, ranged from 6.9% to 13.5%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

[Hemodynamic effects at rest and exertion of a new partial beta-agonist (cicloprolol) in moderated cardiac failure].

The haemodynamic effects of cicloprolol, a new partial beta 1-adrenoceptor agonist, were investigated at rest and during exercise in 10 patients with moderate heart failure. At rest, cicloprolol (0.10 mg/kg i.v.) increased heart rate by 8 p. 100 (80.6 +/- 5.7 vs 74.7 +/- 11.9 beats/min; p less than 0.05), cardiac index by 17 p. 100 (3.74 +/- 0.57 vs 3.20 +/- 0.41 l/min/m2; p less than 0.001) and stroke index by 6 p. 100 (46.3 +/- 8.3 vs 43.7 +/- 8.8 ml/beat/m2; p less than 0.05). Left ventricular end-diastolic pressure was reduced by 35 p. 100 (9.9 +/- 5.0 vs 15.2 +/- 7.4 mmHg; p less than 0.01). There were no significant changes in aortic pressure. Systemic vascular resistance decreased by 15 p. 100 (1,030.8 +/- 234.6 vs 1,209.6 +/- 319.7 dynes.s.cm-5; p less than 0.01). During moderate exercise (114 +/- 13 watts) in supine position, cicloprolol induced a 10 p. 100 reduction of tachycardia (99.7 +/- 10.2 vs 112.2 +/- 16.5 beats/min; p less than 0.01), a 6 p. 100 decrease of mean aortic pressure (112.4 +/- 19.7 vs 119.5 +/- 19.2 mmHg; p less than 0.01) and an 8 p. 100 decrease of cardiac index (5.42 +/- 0.63 vs 5.88 +/- 0.75 l/min/m2; p less than 0.001). There were no significant changes in left ventricular filling pressure and stroke index. When data obtained at rest and during exercise were pooled, an inverse linear relationship (p less than 0.01) was found between heart rate before treatment with cicloprolol and cicloprolol-induced variations in heart rate and cardiac index.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic beta-Agonists

Retrograde catheterization of left ventricle through mechanical aortic prostheses.

Twenty-three patients who had undergone aortic valve replacement with a mechanical aortic valve prosthesis (ball-valve: 17, tilting-disc: 6) were investigated by retrograde left ventricular catheterization using a 6 F pigtail catheter. Twelve of these 23 patients also had had combined aortic and mitral valve replacement. To assess the magnitude of the catheter-induced aortic regurgitation and its effect on left ventricular and mitral valve function, 10 patients (group 1) were simultaneously investigated by the transseptal route (8 patients) or direct left ventricular puncture. The 13 other patients (group 2) were studied only by the retrograde crossing of the aortic valve prosthesis. In group 1, placement of the catheter across the valve induced an increase in heart rate (+12%), in left ventricular end-diastolic pressure (from 17.2 +/- 9.6 to 33.3 +/- 12.0 mmHg), a decrease in aortic systolic (-19%) and diastolic (-25%) pressures, and left ventricular systolic pressure (-10%). Transvalvular aortic pressure gradient increased from 15.4 +/- 8.2 to 23 +/- 12.1 mmHg. Pre- and post-crossing pressure gradients were linearly correlated (r = 0.93). Left ventricular end-diastolic volume increased slightly but significantly (+9%), ejection fraction remained unchanged. Pre- and post-crossing regurgitation fractions were linearly related (r = 0.98). Hence, the magnitude of catheter-induced aortic regurgitation averaged 27% whether or not a pre-crossing regurgitation was noted. In group 2, retrograde crossing of the aortic valve prosthesis induced similar hemodynamic changes. There were no catheterization-related complications.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve