PubMed Health⌕ Search

Biomedical subjects

M Lefèvre

Publications and source records attributed to M Lefèvre.

At least 19 recordsLinked to original sources
PubMed1994

[Hypertrophic cardiomyopathy caused by cytochrome-oxidase deficiency].

Mitochondrial cytopathies are due to genetic anomalies in the oxidative phosphorylation enzymes (excepting Krebs cycle, pyruvate and certain other mitochondrial enzymes). Recently discovered, these diseases have a characteristic heterogeneous clinical expression because of the ubiquitous nature of this intracellular organelle. We observed a case in a 16-year-old girl who had cytochrome C oxidase deficiency. The child was born to non-consanguinous parents and had a healthy brother. The first manifestation of the disease was a systolic murmur heard at the age of 4 years. Progressively, exertion dyspnoea, lipothymia with cyanose led to the first echocardiography at 8 years revealing non-obstructive cardiomyopathy. Functional inadaptation of cardiac performance worsened requiring various symptomatic treatments. At the age of 16, the symptomatology included lower limb fatigue and the diagnosis of a metabolic disease was entertained. Phosphorylase A and B activity and phosphokinase activity were normal. High lactic acid levels after exertion suggested a mitochondrial enzyme deficiency. The diagnosis of cytochrome C oxidase deficiency was confirmed by spectrophotometric and polarographic assay of mitochondria from a peripheral muscle biopsy. Treatment with riboflavin, ascorbic acid, factor P, menadione, carnitine and iron sulfate has currently provided some symptomatic improvement. In patients with unexplained cardiomyopathy, the diagnosis of mitochondrial cytopathy should be entertained if oxidoreduction potentials (lactate/pyruvate ratio) are perturbed. The diagnosis is confirmed by enzyme studies of fresh muscle mitochondria. Currently therapeutic prospects are at best very poor. Genetic counselling may be advisable.

Adolescent↗
PubMed1994

Plague pandemics investigated by ribotyping of Yersinia pestis strains.

Yersinia pestis is the causative agent of plague, a disease which has caused the deaths of millions of people and which persists now in endemic foci. The rRNA gene restriction patterns (i.e., ribotypes) of 70 strains of Y. pestis, isolated on the five continents over a period of 72 years, were determined by hybridization with a 16S-23S rRNA probe from Escherichia coli. The combination of the EcoRI and EcoRV patterns resulted in the elucidation of 16 ribotypes. Two of them (B and O) characterized 65.7% of the strains studied, while the 14 other ribotypes were found in no more than three strains each. A relationship was established between biovars and ribotypes: strains of biovar Orientalis were of ribotypes A to G, those of biovar Antiqua were of ribotypes F to O, and those of biovar Medievalis were of ribotypes O and P. Great heterogeneity in rRNA restriction patterns was found among strains isolated in Africa; this heterogeneity was less pronounced among Asian isolates and was completely absent from the American strains. Pulsed-field gel electrophoresis was performed on the DNAs of some strains, but it appeared that different colonies from the same strain displayed different pulsed-field gel electrophoresis patterns and therefore that this technique was not suitable for comparison of Y. pestis isolates. In contrast, the ribotypes of individual colonies within a given strain were stable and were not modified after five passages in vivo. A clear correlation between the history of the three plague pandemics and the ribotypes of the strains could be established.

Bacterial Typing Techniques↗
PubMed1993

Response to dobutamine and dopamine in the hypotensive very preterm infant.

A randomised double blind study was designed to evaluate haemodynamic response to dobutamine and dopamine in 20 hypotensive preterm infants of less than 32 weeks' gestation. Neonates initially received dopamine or dobutamine 5 micrograms/kg/min. If mean arterial pressure (MAP) remained below 31 mm Hg, the infusion rate was increased in increments of 5 micrograms/kg/min. If 20 micrograms/kg/min of the initial drug failed to achieve a MAP above 30 mm Hg, it was discontinued and the other drug was administered at the same infusion rate. Left ventricular output (LVO) was measured by pulsed Doppler echocardiography. Mean (SE) MAP increased significantly from 24.4 (1.0) to 32.0 (1.4) mm Hg at a median dobutamine dosage of 20 micrograms/kg/min and from 25.6 (1.2) to 37.7 (1.5) mm Hg at a median dopamine dosage of 12.5 micrograms/kg/min. The percentage LVO increase was +21 (7)% with dobutamine compared with -14 (8)% with dopamine. Dobutamine failed to increase MAP above 30 mm Hg in six infants out of 10, whereas dopamine succeeded in all 10 infants. Six switches from dobutamine to dopamine were thus performed, providing a rise in MAP (29.2 (0.5) to 41.2 (2.0) mm Hg) and drop in LVO (356 (40) to 263 (36) ml/kg/min). These data indicate that dopamine is more effective than dobutamine in raising and maintaining MAP above 30 mm Hg; however dopamine does not increase LVO.

Dobutamine↗
PubMed1992

Molecular typing of Brucella with cloned DNA probes.

Brucella constitutes a single genomic species (B. melitensis); however, for epidemiological studies, methods are needed for discriminating strains within this genomic species. DNA samples from 112 Brucella strains were cleaved by restriction endonucleases and the fragments separated by agarose gel electrophoresis and transferred to nylon membranes. When the DNA fragments on the membranes were probed with 32P-labelled 16 + 23 S rRNA from Escherichia coli, a single rRNA gene restriction pattern was obtained after cleavage with all endonucleases tested (HindIII, EcoRI, SmaI, and XhoI) except BamHI. This indicated high genomic homogeneity within the single Brucella species. Of 30 probes consisting of random Brucella DNA fragments cloned into lambda EMBL3, 20 yielded a single BamHI restriction pattern per probe when applied to 112 Brucella DNA tested. However, 7 probes yielded 3 to 12 different patterns among DNA tested. These patterns more-or-less correlated with the classification of strains into biogroups (Melitensis, Abortus, Suis, Neotomae, Ovis and Canis) and biovars (18 biovars represented). Probe A was capable of separating biogroup Melitensis from the other biogroups. Probe C separated the set of biogroups Melitensis-Abortus-Ovis from the other biogroups. By reference to the patterns obtained using 1 to 7 probes, the most frequently occurring biovars (Melitensis 1, Melitensis 3, Abortus 1, Abortus 3, Suis 2 and Ovis) could be distinguished from each other. Eight biovars showed more than one pattern with 1 to 7 probes. The proposed typing system should be useful for epidemiological subtyping and does not pose safety problems once the DNA has been extracted.

Autoradiography↗
PubMed1992

[Intracardiac metastases of primary neuroectodermal tumor].

BACKGROUND: Cardiac metastases from malignant tumors are rare in children and are usually found only at necropsy. CASE REPORT: A girl aged 6 months developed a swelling in the area of her left shoulder. Surgical excision was incomplete and pathological examination indicated neuroectodermic soft-tissue tumor. Chemotherapy with cyclophosphamide, doxorubicin then vincristine and actinomycin D was instituted, followed by second course of cyclophosphamide-doxorubicin. Three months after cessation of chemotherapy, the child developed manifestations of congestive cardiac failure that could not be induced by anthracycline (total cumulative dose: 275 mg/m2). Cardiac ultrasonography showed a metastatic tumor (diam = 3 cm) on the wall of the right ventricle and atrium, which was pedunculated inside the infundibular chamber. It was partly excised, and the patient was treated with etoposide and carboplatin. But a second metastatic tumor formed in the paravertebral area. CONCLUSION: This is the first description, to our knowledge, of cardiac metastases from neuroectodermic tumor. They were diagnosed by cardiac ultrasonography, as this imaging technique differentiates this complication from the anthracycline-induced cardiomyopathy usually seen in children developing cardiac failure under chemotherapy.

Female↗
PubMed1991

[Removal of an anatomic post].

Removing an anatomical cast post requires many precaution and, in most situation, gives very good results. Nevertheless, this procedure can be dangerous for the tooth or the surrounding tissues and must be considered only in case of absolute necessity. Two techniques are described using a little hole made in the coronal part of the core. A threaded wire is driven through this hole making possible the use of a crown remover. For the second technique the use of an original appliance, the ATD bridge remover, is demonstrated with very good results too.

Dental Instruments↗
PubMed1990

[Comparison of magnetic resonance imaging, echocardiography and catheterization in the diagnosis of congenital heart diseases].

The authors compared the diagnostic value of magnetic resonance imaging (MRI), echocardiography and cardiac catheterisation with angiography in 66 patients with congenital heart disease, to determine a diagnostic strategy in the use of these methods of cardiac imaging. The patients were 8 days to 44 years old. The congenital cardiac malformations were classified in three groups: 29 isolated vascular malformations (Group 1), 17 isolated intracardiac malformations (Group 2) and 20 complex malformations (Group 3). MRI was performed in all patients using a high field (1.5 tesla) magnet and spin-echo sequences in multiple incidences. The results were compared with those of echocardiography in 60 patients and/or cardiac catheterisation in 39 cases. Technical evaluation of MRI showed images of diagnostic quality in 62/66 cases (93.9%). MRI provided a diagnostic contribution in 56 cases (85%) which was less important in intracardiac malformations than in the other groups (p less than 0.05). In comparison with other imaging techniques, globally, the diagnostic value of MRI was lower than that of cardiac catheterisation (p less than 0.005) but there was no significant difference between MRI and echocardiography. When the type of malformation was taken into account, MRI was not as useful as catheterisation and echocardiography for the diagnosis of isolated intracardiac malformations (p less than 0.01) but gave comparable results in other malformations. On the other hand, MRI associated with echocardiography was more useful (p less than 0.05) than catheterisation in the diagnosis of complex congenital lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

[Aortico-left ventricular tunnel. Long-term follow-up, therapeutic implications].

Aortico-left ventricular tunnel is a rare entity resulting in a communication between the ascending aorta and the left ventricle, with clinical signs of aortic incompetence. On the basis of two personal cases and a review of the literature including 57 patients, the operative mortality and long-term follow-up of these patients are analysed. 51 patients were operated upon with a mortality rate of 21.5% (11 cases). In this mortality group, 64% of the casualties were less than 2 years' old (7/11). Mortality was unrelated to the surgical technique. Aortic incompetence was the crucial factor of post-operative morbidity. 60% of the patients who were operated upon had significant post-operative aortic incompetence. Among the 21 patients with long-term follow-up (1.5 to 14 years), 17 have aortic incompetence (81%), 8 were reoperated and 7 underwent aortic valve replacement. Surgical repair of this malformation should be considered early in life, and the technique used should aim at consolidating the aortic annulus without deformation and at closing the aortico-ventricular window.

Angiocardiography↗
PubMed1989

[Echocardiographic monitoring of the left ventricle in infants and children presenting the primary form of acute cardiac failure].

A retrospective multicenter study was based on influential echocardiograms performed in 34 children, the majority (29/34) being under 2 years of age, and presenting with a primary form of acute congestive heart failure. Four died early. The average duration of serial echocardiographic monitoring was 25 months (9-72 months) in the others. During the acute stage, the left cardiac cavities were extremely dilated and the shortening fraction was reduced to 15 +/- 4%. The 4 decreased children belonged to a group of 17 children who had a shortening fraction less than 13%. From the 8th day significant improvement of the left ventricular function was observed. Recovery was faster during the first 6 months of evolution and became very low after 1 year. The age at onset, the severity of the initial left ventricular changes, and the speed of recovery during the first 15 days were not predictive of the degree of eventual recovery of left ventricular function. At the end of the study 28 of the 30 surviving children had recovered a normal shortening fraction. However 16 of 30 still showed some dilatation, albeit moderate in most cases, of this ventricle. These data show that most children presenting with a primary form of acute congestive heart failure recover satisfactory heart function and that the initial echocardiographic features are not predictive of the subsequent course.

Acute Disease↗
PubMed1989

[Removal of fixed prosthetics].

Unscaling a fixed prosthesis can be dangerous for the supporting tissue. However a careful examination of the clinical situation and the proper use of correct technics described in the following article, may prudence a successful result most of the time.

Crowns↗
PubMed1989

[Diagnostic models. 2. Fabrication].

After describing in Part I the preparation of diagnostic cast, the authors describe the Wax Up preparation. Most of the definition of centric relation agree that the position of the mandible is slightly behind its position in centric occlusion. The Hinge axis position is used for mounting the cast on articulator. The final restauration must reconstruct both position and the occlusion should be established in front the centric occlusion. After equilibration anterior guidance is studied and restaured if necessary. After creating the different curve of occlusion, the final Wax Up is settled. The use of the diagnostic cast so obtained will be presented in Part III.

Dental Articulators↗
PubMed1986

[Fatal form of pericardo-myocarditis in Wissler-Fanconi syndrome].

The Wissler-Fanconi syndrome is an inflammatory disease of unknown origin, similar to Still's disease, a systemic form of juvenile arthritis. The long-term evolution is marked by recurrent febrile exacerbations, sometimes complicated by pericardo-myocarditis which usually resolves without sequellae. The authors report a case with chronic pericardo-myocarditis progressing over a 7 year period to refractory congestive cardiac failure.

Adult↗
PubMed1985

[Treatment of hypertrophic cardiomyopathy].

The treatment of hypertrophic cardiomyopathy is first and foremost symptomatic, its aim being to counteract dyspnea, angina pectoris, syncopes and lipothymias, palpitations. In therapy, use is made of beta-blockers, propranolol in particular at moderate or high doses, which are often efficacious but readily cause muscular asthenia. Calcium antagonists, especially verapamil, are a therapeutic alternative, often more efficacious but exposing the patient to the risks of iatrogenic effects which are sometimes serious and may even be fatal. Surgical myomectomy is another alternative, the functional results of which are remarkable, more often than not, but the mortality at surgery, although declining progressively, is not negligible and leads to this approach being used only in cases not responding to medical treatment as when infra-aortic septal hypertrophy is accompanied by an "obstruction". The second type of therapeutic approach is the treatment and prevention of rhythmic disorders which are an integral part of the risk of sudden death. Reduction of auricular fibrillation must play a role in the prevention of thrombo-embolic disease. Ventricular arrhythmias, especially sustained attacks of ventricular tachycardia systematically detected by ambulant ECG, ought to be prevented by anti-arrhythmics: beta-blockers, in combination or not with anti-arrhythmics of class I, amiodarone, propafenone, etc.

Adrenergic beta-Antagonists↗
PubMed1985

[Ergospirometry after repair of Fallot's tetralogy].

Ergospirometry was performed in 19 children and adolescents operated for tetralogy of Fallot (TOF) to assess their exercise capacity compared to an active non sportive control group. The test was carried out on a treadmill with measurement of oxygen consumption cycle by cycle throughout exercise. In comparison with the control group, the patients had: a working capacity which was normal or reduced by 30 to 40 p. 100; a decrease d'oxygen consumption (-30 to 40 p. 100) throughout exercise and at maximal effort: this corresponds to a lower stroke volume secondary to the absence of physical activity during childhood and/or residual cardiac lesions; abnormal chronotropism: the test was stopped at a lower heart rate corresponding to a fall in oxygen uptake during exercise, or to an increase in the systolic ejection period probably due to right ventricular dysfunction or to the patient reaching maximal ventilation; decreased maximal ventilation capacity due to a lower tidal volume and a higher respiratory rate. This type of ventilation increases to role of the dead space and may be related to progressive "pulmonary dysfunction" or secondary to residual cardiac lesions. These different parameters cannot be assessed by simple ergospirometry: the test must be coupled with an evaluation of ventilatory function on effort in order to control and evaluate the long term functional results and the aptitude of these patients to regular physical activity.

Adolescent↗
PubMed1984

[Long-term evaluation, physical and sports activities after correction of Fallot's tetralogy].

The aim of this study was to assess the result of surgical repair of Fallot's tetralogy (FT) and to advise physical and sporting activities. Thirty-two patients (20 boys and 12 girls) underwent correction of FT either before 4 years of age (14 cases) or after (18 cases). The patients were assessed on average 7.5 years postoperatively (range 4 to 13 years). All but one were class I of the NYHA classification. Radiological cardiomegaly was observed in 3 cases (CTI greater than 0.55). Sinus rhythm was present in all cases: 27 out of 30 had complete right bundle branch block without bifascicular block. Holter monitoring was performed in 22 cases: occasional monomorphic VES (1 to 15/hour) were observed in 7 cases. Frequent polymorphic VES were observed during exercise in one adult. Echocardiography and cardiac catheterization revealed pulmonary regurgitation and right ventricular dilatation in over half the cases, with an infundibular aneurysm in 2 cases and a residual pressure gradient of 55 and 66 mmHg in 2 other cases requiring reoperation. Left ventricular function was satisfactory in all cases. Treadmill exercise testing was performed in 28 patients. However, for statistical analysis 12 boys aged 7 to 15 years were compared with 11 controls of the same age. There was a significant decrease in maximal O2 consumption, of CO2 excretion, of ventilation, of heart rate, of work developed and total work in the operated patients. Clinical assessment and complementary investigations are essential 5 to 10 years after correction of FT to detect latent abnormalities and to better advise patients on physical and sporting activities.

Adolescent↗