Search PubMed⌕ Search

Biomedical subjects

M Lefèvre

Publications and source records attributed to M Lefèvre.

At least 19 recordsLinked to original sources
PubMed2006

Detection of occult carcinomatous diffusion in lymph nodes from head and neck squamous cell carcinoma using real-time RT-PCR detection of cytokeratin 19 mRNA.

The aim of the present study was to evaluate the occult lymph node carcinomatous diffusion in head and neck squamous cell carcinoma (HNSCC). A total of 1328 lymph nodes from 31 patients treated between 2004 and 2005 were prospectively evaluated by routine haematoxylin-eosin-safran (HES) staining, immunohistochemistry (IHC) and real-time Taqman reverse-transcriptase polymerase chain reaction (real-time RT-PCR) assay. Amplification of cytokeratin 19 (CK19) mRNA transcripts using real-time RT-PCR was used to quantify cervical micrometastatic burden. The cervical lymph node metastatic rates determined by routine HES staining and real-time RT-PCR assay were 16.3 and 36.0%, respectively (P<0.0001). A potential change in the nodal status was observed in 13 (42.0%) of the 31 patients and an atypical pattern of lymphatic spread was identified in four patients (12.9%). Moreover, CK19 mRNA expression values in histologically positive lymph nodes were significantly higher than those observed in histologically negative lymph nodes (P<0.0001). These results indicate that real-time RT-PCR assay for the detection of CK19 mRNA is a sensitive and reliable method for the detection of carcinomatous cells in lymph nodes. This type of method could be used to reassess lymph node status according to occult lymphatic spread in patients with HNSCC.

Adult↗
PubMed2005

Molecular oxygen reduction in PEM fuel cell conditions: ToF-SIMS analysis of co-based electrocatalysts.

A series of Co-based electrocatalysts for oxygen reduction in acid media has been prepared using two different Co precursors: cobalt acetate (CoAc) and a cobalt porphyrin (CoTMPP). These catalysts have been analyzed by ToF-SIMS to obtain information on the number and the structure of catalytic active sites in these materials. The results are compared with the results of a similar analysis already performed on a series of Fe-based electrocatalysts (J. Phys. Chem. B 2002, 106, 8705) also prepared with two different Fe precursors: iron acetate (FeAc) and an iron porphyrin (ClFeTMPP). The interpretation of ToF-SIMS data for Fe-based catalysts allowed us to conclude that whatever the Fe precursor was, the same catalytic sites (FeN2/C and FeN4/C, with their respective dominant ToF-SIMS signatures: FeN2C4+ and FeN4C8+ ions) were found. The comparison of the ToF-SIMS data with the activity of those catalysts led to the conclusion that the FeN2C catalytic site was more active than FeN4/C. When the same procedure is applied to ToF-SIMS data measured for Co-based catalysts, the following conclusions are drawn: (i) as for Fe precursors, both Co precursors also give similar results; (ii) as for Fe-based catalysts, the same four families of MetalNxCy+ ions, with 1, 2, 3, and 4 nitrogen atoms, are also found in the spectra of Co-based catalysts, but there is no dominant CoNxCy+ ion signature; (iii) only CoN4/C can be ascertained on the basis of ToF-SIMS measurements. There is no strong support from ToF-SIMS measurements for (or against) the existence of CoN2/C in Co-based catalysts as there is for FeN2/C in Fe-based catalysts; (iv) contrary to Fe-based catalysts, all catalytic sites (if there are any besides CoN4/C) are about equally active in Co-based electrocatalysts.

Journal Article↗
PubMed2005

[Non-compaction of the myocardium in childhood].

Non compaction of the ventricular myocardium is a rare and severe myocardiopathy with numerous trabeculations and deep intertrabecular recesses directly connected with the ventricular cavity. Many complications may occur: heart failure, arrythmia, thrombotic events. However, phenotypic and genotypic presentations vary. Non compaction affects infants in almost half of the cases. A pediatric national cohort study (directed by the filiale de cardiologie pédiatrique de la société française de cardiologie) should allow to analyse the clinical and epidemiological characteristics of the patients as well as to accurate both non compaction's diagnosis and prognosis. Inclusion criteria of this retrospective multicenter study were: age lesser than 18, echographic and/or histologic criteria of non compaction, no congenital heart disease such as pulmonary atresia. This population included 38 patients: 21 were asymptomatic at diagnosis. Ten familial forms were detected. The ECG was abnormal in 77% of the cases, the chest-X ray in 80%. Echocardiography remains the usual technique for diagnosis. However, previously reported quantitative criteria are not easy to use in a retrospective study. Treatment was symptomatic as the etiology of non compaction is unknown. The prognosis is severe: 31.5% of the patients died or had a cardiac transplantation. Only 30% of the patients were free of cardiac events for a 2-year period. Inclusion of new patients must go on to set up a prospective study and biomolecular analysis in informative families.

Adolescent↗
PubMed2004

[Predictors of in-hospital mortality in the surgical management of acute type A aortic dissections: impact of anticoagulant therapies].

OBJECTIVE: The purpose of this investigation was to study the incidence and consequences of anticoagulant therapy in the surgical management of acute aortic dissections. STUDY DESIGN: Retrospective study. PATIENTS AND METHODS: We reviewed all acute type A aortic dissections that were surgically managed in our institution from 1 January 1990 to 31 December 2000. Survival outcome and characteristics potentially associated with survival were abstracted from patient records. We screened preoperative electrocardiograms (ECG) and anticoagulant therapy. RESULTS: ST segment elevation incidence was 14% and preoperative anticoagulant therapy occurred in 63 (20%) cases as follow: aspirin 12%, aspirin + heparin 6%, thrombolysis 1%. Overall mortality was 22%. Time between pain and surgery was not statistically different between anticoagulant therapy and standard group. Administration of antithrombotic agents before admission in -hospital increased significantly mortality (Odds ratio (OR) = 2.02; IC [1.1-3.71]; p = 0.023). Other risk factors for death were preoperative circulatory failure (OR = 8.28 [4.23-16.24], p < 0.0001), preoperative cardiac arrest (OR = 21.92 [7.16-67.14], p < 0.0001), preoperative circulatory arrest (OR = 2.79 [1.60-4.88], p = 0.0003), preoperative cerebral perfusion (OR = 2.45 [1.18-5.05], p = 0.016), postoperative circulatory failure (OR = 3.37 [1.85-6.17], p < 0.0001), postoperative cardiac arrest (OR = 9.92 [3.49-28.21], p < 0.0001), postoperative serum creatinine >150 micromol/l (OR = 4.55 [2.43-8.50], p < 0.0001), postoperative dialysis (OR = 5.63 [2.44-13.20], p < 0.0001), more than 7 days of post-operative ventilation (OR = 23.44 [12.0-45.7], p < 0.0001). DISCUSSION: In our experience, 20% of acute type A aortic dissections had received a preoperative anticoagulant therapy. This event is an independent risk factor of in-hospital death and is more frequent in case of ischaemic ECG abnormalities.

Aged↗
PubMed2002

[Endocarditis and congenital heart disease in the adult].

The prevalence of congenital cardiopathy is approximately 8% of live births, and 80 to 85% of patients reach adulthood thanks to the progress in the management of even complex malformations. Congenital cardiopathies represent 10 to 18% of adulthood cardiopathies complicated by infectious endocarditis, and in the specialist units for adolescent and adult congenital cardiac patients, 5% of admissions are provoked by endocarditis. The majority of malformations have a risk of infected graft, but patients who have a complex cyanogenic cardiopathy or an operated cardiopathy requiring insertion of prosthetic material, and those who have already had previous episodes of endocarditis are at a very high risk. Longitudinal studies show evolution of the responsible microbes, with an increase of the HACEK group; nevertheless, the streptococci and staphylococci remain uppermost. Diagnosis relies on the classic Duke University criteria but Doppler echocardiography is sometimes difficult to interpret in complex malformations or extra-cardiac sites of infection, and in 6 to 11% of cases the microbe is not identified. Infectious endocarditis remains a particularly serious complication: 50% of patients have aggravation of their cardiopathy and 20 to 30% require surgery; however the mortality has fallen by 20% to a little less than 5% in the most recent series. It is vital that patient education should be pursued even if, in certain circumstances, prophylaxis is not always either possible or effective....

Diagnosis, Differential↗
PubMed2000

Oligonucleotide probe for the visualization of Escherichia coli/Escherichia fergusonii cells by in situ hybridization: specificity and potential applications.

There are several occasions when enumeration of Escherichia coli cells is needed. These include examination of urine specimens and water or food samples. Present methods rely on growth in more or less selective media (colony-forming units on agar or the most probable number method using liquid media). Unfortunately, no really selective medium with 100% efficiency of plating is available for E. coli. A 24-mer oligonucleotide probe (Colinsitu), complementary to a piece of 16S ribosomal ribonucleic acid, has been tested for specifically visualizing E. coli cells by in situ hybridization and epifluorescence microscopy. The fluorescent dye-labeled probe was able to stain cells of E. coli, Shigella spp. and E. fergusonii. Shigella spp. are known to belong to the E. coli genomospecies and E. fergusonii is the nomenspecies closest to E. coli by DNA-DNA hybridization. The probe did not stain any strain of 169 other genomospecies of the family Enterobacteriaceae or of a few other species frequently encountered in the environment. Revivification without cell division allowed the visualization of E. coli cells in contaminated water. In situ hybridization using the Colinsitu probe is a potential tool for the confirmation of (atypical) E. coli in reference centers and the rapid (3-6 h) detection and enumeration of E. coli in urine specimens, contaminated water and food. More work is needed to include in situ hybridization in laboratory routine.

Escherichia↗
PubMed1997

[Prognosis and outcome of idiopathic dilatation of the right atrium in children. A cooperative study of 15 cases].

Idiopathic dilatation is a rare abnormality corresponding to isolated aneurysmal dilatation of the right atrium, the outcome of which is not well known. Therefore a multicentric retrospective study was set up by the paediatric working group of the French Society of Cardiology recensing 7 boys and 8 girls who were diagnosed with this condition between 1971 and 1993. Ten of the children were asymptomatic and the diagnosis was suggested by the chest X-ray: one neonate had cardiac failure secondary to atrial tachycardia. The diagnosis has been facilitated by echocardiography since 1980. In this series, since 1993, four diagnoses were made antenatally. The outcome was variable : eight children are alive and well with follow-up periods ranging from 2 to 15 years (average 6 years) : four children have had cardiac arrhythmias : benign atrial extrasystoles (1 case), junctional reentrant tachycardia (1 case). The other two had more severe arrhythmias with flutter in a 7 year-old and one neonatal atrial tachycardia. The outcome was favourable with medical treatment. Three children underwent surgical atrial resection : the outcome has been good in these 3 cases with follow-up periods of 4, 13 and 18 years. This series shows that idiopathic dilatation of the right atrium is usually a well tolerated abnormality but unexpected complications may arise which can be severe such as arrhythmias, or which may be potentially threatening such as interatrial thrombosis. Management consists of either follow-up to diagnose complications which require appropriate treatment of systematic surgical correction as some authors suggest.

Adolescent↗
PubMed1997

[2 familial cases of metachromatic leukodystrophy of late onset].

We report here a familial observation of metachromatic leukodystrophy (MLD) in 2 sisters. The very beginning, with only psychiatric manifestations at adolescence, could be precisely established. The evolution towards a dementia, and the evidence of a pyramidal syndrome oriented later towards a clearly organic disease. A very wide bilateral and symmetrical demyelination was shown by Magnetic Resonance imaging. The deficiency in arylsulfatase A activity oriented towards MLD which was confirmed by metachromatic deposits in the nerve biopsy. Molecular biology evidenced in the two, compound heterozygoty with both the classical mutation of the infantile form with loss of a splicing site at the level of intron 2, and the ileu > Ser 179 mutation frequent in adult forms.

Aged↗
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↗