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Biomedical subjects

B Chevalier

Publications and source records attributed to B Chevalier.

At least 19 recordsLinked to original sources

[A mild blackwater fever].

We report a highly probable case of moderately severe blackwater fever. A French woman, living in Guinea Bissau, was used to taking self-medication halofantrine for malaria. On this occasion, she felt unusual chills and pyrexia after a non documented bout of malaria, followed by nausea, then jaundice with dark-red urines despite another treatment with halofantrine. A sepsis was eliminated by two negatives thick peripheral blood drop examinations. Hemolysis was noted with 8.1 g/dl of hemoglobin, Coombs positive, and LDH at 1,452 IU/l, associated to renal failure with 34 ml per minute of clearance. The outcome was favourable with rehydration. Blackwater fever has been described with the three aminoalcohols, but mainly in severe presentations. Clinicians are not familiar with this disease, even though it has major therapeutic implications: quinine, halofantrine, and mefloquine become strictly contra-indicated. Moderate forms may be unknown, and this observation should be taken into account to prevent mistreatment in future patients.

Acute Kidney Injury↗

[The best of interventional cardiology in 2005].

During 2005, the evolution of interventional cardiology has largely been dominated by the trial of active endoprostheses, whose advantage has been consistently shown by various studies, mete-analyses and surveys. Extending their use to new indications and evaluating new drugs have also been studied. In parallel, clinical trials have been performed in the promising field of percutaneous treatment of valvular heart disease, particularly mitral insufficiency and calcified aortic stenosis in the adult.

Blood Vessel Prosthesis↗

[Role of Musca domestica in the transmission of multiresistant bacteria in the centres of intensive care setting in sub-Saharan Africa].

OBJECTIVE: The houseflies (Musca domestica -MD) are involved in the transmission of the diseases of the faecal danger in subsaharan Africa. What is their role in the transmission of multiresistant bacteria in an intensive care setting in Dakar? TYPE OF STUDY: Descriptive, forward-looking. MATERIALS AND METHODS: The study was conducted from May 1 to September 30, 2003. During this period a flytrap was put above every patient carrier of BMR (methicillin resistant Staphylococcus, extended spectrum beta-lactamases-enterobacteria, ticarcillin resistant Pseudomonas). Caught MD were carried to the microbiology laboratory and incubated in heart-brain broth at 37 degrees C for 18 hours. Then selective gelose platers were used for identification of bacteria. Comparison of antibiotic sensitivities of bacteria isolated from MD and from the patients was made. RESULTS: Out of 441 hospitalized patients, 26 were colonised or infected by BMR. Human pathogenic microorganisms were obtained from 99 out of 120 flies. Seventeen of those flies were carried of BMR. Six among these 17 flies had BMR with sensitivity profile and phenotype of resistance identical to those of the patients under the trap with birdlime. More 3 MD carried BMR BLSE not found on our patients. CONCLUSION: This study shows that the MD can carry BMR. Their participation in the crossed transmission, between patients, of multiresistant bacteria in intensive care setting, must be discussed. The eradication of the MD in our Africa subsaharan services must be looked for.

Adolescent↗

[Acute coronary syndromes without ST elevation. State-of-the-art, recommendations, and best practices].

In the last decade, acute coronary syndromes without ST elevation (ACS ST-) have become a clinical entity encompassing previous technologies such as acute coronary insufficiency and non-Q wave myocardial infarction. The recognition of its risks and, above all, the development and adaptation of medical and interventional strategies have transformed the prognosis. Patients presenting with ACS ST- are not all identical and do not all have the same prognosis; based on this observation, a number of prognostic scores have been proposed which help decide whether to use drugs such as GP IIb/IIIa inhibitors or coronary angioplasty. Conservative and aggressive strategies are opposing choices but risk stratification allows the treating physician to take a safe decision in the majority of cases. Besides angioplasty and GP IIb/IIIa inhibitors, the basic treatment (aspirin, low molecular weight heparin, clopidogrel, betablockers) should of course be prescribed and its efficacy has contributed to a better outcome in these patients. The recommendations of the scientific societies have evolved with time and increased understanding, allowing an evidence-based approach to the management of ACS ST- patients.

Algorithms↗

[Clinical and laboratory features of typhoid fever in Senegal. A 70-case study].

Clinical and laboratory features, complications and treatment were retrospectively studied in 70 patients with bacteriologically documented typhoid fever, treated between January 1995 and June 2002 at Principal Hospital in Dakar, Senegal. Data analysis was done on a global basis as well as comparatively between the 37 children (under 15 years) and 33 adults. Mean age was 16.7 years (range, 1 to 52). The sex ratio was 1.4. Clinical manifestations included fever (97%), headache (50%), vomiting (71%), abdominal pain (54%), diarrhoea (49%), nnd splenomegaly (10%) without statistically significant difference between children and adults. Lyinphopenia was found in 51% of patients and anaemia in 78%. Coexisting illnesses Included malaria in 25.5% (mainly children) and hepatitis (transminases > 10N) in 24%. Complications included cholecystitis in 3 patients, gastrointestinal haemorrhage in 2, peritonitis in one, endocnrditis in one and osteomyelitis in one. Only one patient (HIV-positive) died. The incidence of antibiotic resistance was low, i.e., ainoxicilline: 2%, nalidixic acid: 1% and cotrimoxazole: 8.2%. No multidrug resistance was observed. This study shows that typhoid fever remains a major health problem in Dakar with slow resolution and potential complications. Amoxicililne and chloramphenicol can still be used for first-line treatment of typhoid fever. Little difference was found between children and adults.

Adolescent↗

Investigation of the electronic and structural properties of potassium hexaboride, KB6, by transport, magnetic susceptibility, EPR, and NMR measurements, temperature-dependent crystal structure determination, and electronic band structure calculations.

The electronic and structural properties of potassium hexaboride, KB(6), were examined by transport, magnetic susceptibility, EPR, and NMR measurements, temperature-dependent crystal structure determination, and electronic band structure calculations. The valence bands of KB(6) are partially empty, but the electrical resistivity of KB(6) reveals that it is not a normal metal. The magnetic susceptibility as well as EPR and NMR measurements show the presence of localized electrons in KB(6). The EPR spectra of KB(6) have two peaks, a broad ( approximately 320 G) and a narrow (less than approximately 27 G) line width, and the temperature-dependence of the magnetic susceptibility of KB(6) exhibits a strong hysteresis below 70 K. The temperature-dependent crystal structure determination of KB(6) shows the occurrence of an unusual variation in the unit cell parameter hence supporting that the hysteresis of the magnetic susceptibility is a bulk phenomenon. The line width DeltaH(pp) of the broad EPR signal is independent of temperature and EPR frequency. This finding indicates that the line broadening results from the dipole-dipole interaction, and the spins responsible for the broad EPR peak has the average distance of approximately 1.0 nm. To explain these apparently puzzling properties, we examined a probable mechanism of electron localization in KB(6) and its implications.

Journal Article↗

[Active stents: towards total prevention of restenosis?].

To avoid in-stent restenosis, a new technologic approach with "coated" stents may deliver local cytostatic products (sirolimus, paclitaxel, tacrolimus...). At this time, present clinical studies validate the importance of these active coated stents in sub-groups of patients with diabetes, long lesions, small vessels and proximal left anterior descending coronary lesions.

Coronary Restenosis↗

[DRESS syndrome to allopurinol: a case in Dakar].

We report a case of DRESS syndrome also called drug hypersensitivity reaction occurring a 47 years old Senegalese man who has been taking allopurinol for 3 months. That drug was prescribed for peripheric arthralgias associated to a hyperuricemia. He presented a generalised pruritus, cutaneous lesions, fever and facial oedema. On the biological examens, hyperleucocytosis with hypereosinophilia and hyperlymphocytosis associated to the presence of segmented basophiles. In addition, a hepatic cytolysis and cholestasis were documented. Liver ultrasound was normal. The hemocults were negative. These following serologies have been performed and were negative: hepatitis B and C, Epstein Barr-virus, cytomegalovirus, syphilis, toxoplasma and parvovirus B19. The anti-nuclear and anti-DNA antibodies were negative. A favourable clinical evolution was remarked after allopurinol treatment withdrawal. A desquamation occurred after 6 days and hemogram turned out to the normal as well as the hepatic tests after 2 weeks. The virologic examens performed 2 months later were unremarkable. This case point out the importance of the early diagnosis and quick withdrawal of the drug in order to prevent serious forms leading to the 10% of death.

Allopurinol↗

Unusual hysteresis in the magnetic susceptibility of cubic hexaboride KB6.

Electrical resistivity, magnetic susceptibility, and electron paramagnetic resonance measurements were carried out for cubic hexaboride KB(6), which is one electron short of completely filling its conduction band. It is found that KB(6) is not metallic and has localized spins. KB(6) exhibits a highly unusual hysteresis in the magnetic susceptibility below 100 K, which suggests that it undergoes a slow relaxation process.

Journal Article↗

[FACT: French national registry of acute coronary syndromes. Specific study of French general hospital centers].

UNLABELLED: The FACT registry is currently the French registry including the greatest number of patients with acute coronary syndromes. PURPOSE: The study presents epidemiologic data, modalities and delays for medical admission. METHOD: Three thousand nine hundred and two patients were included in FACT by 362 French centers of cardiology between 06/01/2003 and 03/02/2003. One thousand eight hundred and ten patients, who had been placed in the cardiology departments of French general hospitals, were isolated from this registry. The French general hospitals represented 50.8% of the 362 centers. In order to clarify the study, these patients were divided into three groups: group A: patients without ST segment elevation but with suggestive ECG modifications; group B: patients with ST segment elevation; group C: all other patients. The results were mainly studied for groups A and B and compared. These results were also compared to those of the FACT registry and of other registries. RESULTS: The results show that the average delay for admission is 2.9 h after a first delay between the pain and the help of 6.7 h. The first intervening party is a general practitioner (36.4%) then the SAMU (31.6%) and finally the emergency departments (18.7%). 16.6% of the patients from group B undergo pre-hospital thrombolysis. The recommendations of the European Society of Cardiology are widely applied except for the most recent of them since only 27.6% of the patients from group A having a TIMI score > or = 5 receive an anti-GIIB IIIA treatment. The reasons of the non-prescription of the recommended classes are mostly linked to contra-indication and intolerance. The strategy of coronary reopening mainly depends on the presence or the absence in the department of an available medical equipment for angioplasty. If there is one, the percentage of primary angioplasty reaches 54.2% and the percentage of thrombolysis 7.9%. On the opposite, there is 8.3% of angioplasty and 54.2% of thrombolysis for the unequipped centers. The global mortality reaches 5.8% but is inversely proportional to the level of equipment of the departments: 5.9% for the departments with angioplasty, 11% for the departments with coronarography but without angioplasty and 13.8% for the departments without any interventional equipment. Nevertheless, the age of the patients is different and this influences the results: we notice that the less equipped the department is, the older the patients are. CONCLUSION: The FACT registry and the data from the general hospitals give the opportunity to think about the possibilities to improve the delays of call to the first intervening party (more particularly to the SAMU) but it also allows us to think about how to better organize the geographical distribution giving access to a medical equipment for angioplasty. All these information will also help the cardiologists to gather around the recommendations by convincing them that the benefit/risk ratio is positive.

Adult↗

Muscle development, insulin-like growth factor-I and myostatin mRNA levels in chickens selected for increased breast muscle yield.

Insulin-like growth factor-I (IGF-I) and myostatin (MSTN) are paracrine regulators of muscle growth. The present study was conducted to relate their expression with muscle fibre development in chickens selected for high breast meat yield and their controls. Both mRNA levels were measured by real-time RT-PCR in the Pectoralis major (PM) muscle between 14 days in ovo and 6 weeks post-hatch and in the Sartorius (SART) muscle between 2 and 6 weeks. The data show that PM growth was slow during in ovo development and rapid in the early post-hatch period. Chickens from the selected genotype exhibited significantly higher breast muscle yields from 2 to 6 weeks of age, and muscle fibre hypertrophy. In the PM, IGF-I and MSTN mRNA levels decreased markedly around hatch, while the IGF-I/MSTN ratio increased, suggesting that it could contribute to the explosive growth observed in the early post-hatch period. Between 4 and 6 weeks of age in selected chickens, IGF-I mRNA levels were significantly higher (p=0.04) with a similar trend in MSTN mRNA levels (p=0.07) in the PM muscle but not in the SART muscle. Our results support the hypothesis that the relative levels of IGF-I and MSTN mRNA may participate to set muscle growth rate along development, while other factors are required to explain differences between genotypes.

Animals↗

[The best of coronary atheroma and interventional cardiology in 2002].

The year 2002 in interventional cardiology was monopolised by the concept of the active stent. Each step of the restenosis process can be targeted by the active principle: platelet thrombosis, inflammation, smooth muscle cell migration, smooth muscle cell proliferation. At this stage, only sirolimus and paclitaxel have successfully completed the clinical validation process in simple lesions. Certain questions remain unresolved: far from 0% restenosis, why are these devices less effective in lesions at high risk of restenosis? Why does sirolimus stent usage create effects of restenosis on the edges and why is it present in cases of positive remodelling of the artery for which the clinical role is still unknown? Above all, will the late escapement of the restenotic process observed in the animal model have a clinical correlation when there is a longer follow up? It is still too soon to know if paclitaxel will raise the same questions. Indications not yet completely validated for the metallic endoprosthesis are disappearing little by little: acute infarction, long lesions. At last restenosis has been put in its proper place: the rate of re-intervention at 9 months remains less than 15% in the whole of the Presto study; systematic angiographic follow up at 6 months in the Trends study shows a restenosis rate of 13% on average. So the boundary between active stent and metallic stent seems more blurred than in 2001 when the results of the sirolimus studies were not available. The detection of ruptured or about to rupture plaque is a challenge which seems to be in hand now with techniques such as endocoronary echography or even more emergent techniques such as thermography, optical coherence tomography, or elastography. Which plaques should be treated? With medication? With mechanical tools? The work of the Lyon team on the clinical follow up of unstable plaques reveals a good prognosis for these plaques once the "guilty" lesion has been treated. The future of these techniques is thus perhaps more orientated towards primary prevention than towards secondary prevention.

Animals↗