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Biomedical subjects

F Guerin

Publications and source records attributed to F Guerin.

At least 19 recordsLinked to original sources
PubMed2000

Fluoroquinolone resistance associated with target mutations and active efflux in oropharyngeal colonizing isolates of viridans group streptococci.

Oropharyngeal samples from 60 hospitalized patients (30 fluoroquinolone [FQ]-treated and 30 non-FQ-treated patients) and 30 untreated nonhospitalized healthy control subjects yielded 20 isolates of viridans group streptococci with reduced susceptibility to FQ, mostly from the hospitalized patients. An efflux phenotype was commonly encountered, expressed either alone or with topoisomerase mutations. Interspecies transfer of the efflux phenotype was demonstrated via transformation of Streptococcus pneumoniae R6 with DNA from S. mitis and S. oralis.

Anti-Infective Agents↗
PubMed2000

Outbreak of methicillin-resistant Staphylococcus aureus with reduced susceptibility to glycopeptides in a Parisian hospital.

Epidemiological relationships were investigated between 40 methicillin-resistant Staphylococcus aureus (MRSA) strains with decreased glycopeptide susceptibility isolated from November 1998 to March 1999 from 39 patients (17 infected and 22 colonized patients) in nine wards of the Broussais Hospital, Paris, France. Reduced glycopeptide susceptibility was readily detected on brain heart infusion (BHI) agar containing 6 microg of teicoplanin per ml and on gradient plates, but not by the standard disk diffusion method. The MICs of vancomycin and teicoplanin, determined on BHI agar, were 4 and 8 to 32 microg/ml, respectively (standard antibiotic dilution), and 4 to 8 and 8 to 32 microg/ml, respectively (E-test). All strains were resistant to macrolides, aminoglycosides, tetracycline, rifampin, sulfonamides, and pefloxacin, showed reduced susceptibility to fusidic acid and fosfomycin, and were susceptible to trimethoprim and chloramphenicol. Pulsed-field gel electrophoresis and lysotyping revealed that a multidrug-resistant MRSA clone with decreased susceptibility to glycopeptides has been discretely endemic since at least 1996 in our institution, where it was responsible for an outbreak in November and December 1998.

Anti-Bacterial Agents↗
PubMed1998

[Vancomycin resistant enterococcus in France. High prevalence in a young ambulatory care patient population].

OBJECTIVE: Assess the prevalence of asymptomatic carriage of vancomycin-resistant Enterococci in a population of healthy young French subjects. METHODS: Stool samples obtained from 100 persons living in south-eastern France (20 sampling sites) were directly seeded on enriched selective media containing 6 mg/l vancomycin. Bacterial species and their resistant gene were identified with classical methods and multiplex genomic amplification. RESULTS: The incidence of asymptomatic carriage was 17% with a homogeneous geographic distribution of the resistant strains. Nine Enterococcus faecium van A strains and 8 E. gallinarum van C1 strains were isolated. CONCLUSION: These findings demonstrate carriage of vancomycin-resistant Enterococci in a population of young ambulatory subjects in France. The incidence observed was much higher than in an earlier study conducted in France. These results might be explained by a much more sensitive detection technique. Care should be taken to avoid dissemination in hospital settings.

Adult↗
PubMed1995

Serum galactosyltransferase activities in newborn children and pregnant women.

We have compared serum galactosyltransferase activity in pregnant women and in newborn children. Subjects in this study were 75 women at different stages of pregnancy and 60 newborns, including premature infants. Activity ratios in pregnant women are based on the period of gestation, expressed in weeks of amenorrhea. Average values were 265 nmol/h/ml for up to 12 weeks of amenorrhea, 369 from 13 to 28 weeks and 483 over 28 weeks versus 232 nmol/h/ml for non-pregnant women. In infants, galactosyltransferase activity decreased with increasing age from conception, but the activity level was always much higher in newborns than in women at the ninth month of pregnancy. We discuss the origin of the enzyme in these various samples.

Female↗
PubMed1992

Improvement in exercise performance by inhalation of methoxamine in patients with impaired left ventricular function.

BACKGROUND: Bronchial hyperresponsiveness to cholinergic stimuli such as the inhalation of methacholine is common in patients with impaired left ventricular function. Such hyperresponsiveness is best explained by cholinergic vasodilation of blood vessels in the small airways, with extravasation of plasma due to high left ventricular filling pressure. Because this vasodilation may be prevented by the inhalation of the vasoconstrictor agent methoxamine, we studied the effect of methoxamine on exercise performance in patients with chronic left ventricular dysfunction. METHODS: We studied 19 patients with a mean left ventricular ejection fraction of 22 +/- 4 percent and moderate exertional dyspnea. In the first part of the study, we performed treadmill exercise tests in 10 patients (group 1) at a constant maximal workload to assess the effects of 10 mg of inhaled methoxamine on the duration of exercise (a measure of endurance). In the second part of the study, we used a graded exercise protocol in nine additional patients (group 2) to assess the effects of inhaled methoxamine on maximal exercise capacity and oxygen consumption. Both studies were carried out after the patients inhaled methoxamine or placebo given according to a randomized, double-blind, crossover design. RESULTS: In group 1, the mean (+/- SD) duration of exercise increased from 293 +/- 136 seconds after the inhalation of placebo to 612 +/- 257 seconds after the inhalation of methoxamine (P = 0.001). In group 2, exercise time (a measure of maximal exercise capacity) increased from 526 +/- 236 seconds after placebo administration to 578 +/- 255 seconds after methoxamine (P = 0.006), and peak oxygen consumption increased from 18.5 +/- 6.0 to 20.0 +/- 6.0 ml per minute per kilogram of body weight (P = 0.03). CONCLUSIONS: The inhalation of methoxamine enhanced exercise performance in patients with chronic left ventricular dysfunction. However, the improvement in the duration of exercise at a constant workload (endurance) was much more than the improvement in maximal exercise capacity assessed with a progressive workload. These data suggest that exercise-induced vasodilation of airway vessels may contribute to exertional dyspnea in such patients. Whether or not inhaled methoxamine can provide long-term benefit in patients with heart failure will require further study.

Administration, Inhalation↗
PubMed1992

[Acute heart insufficiency in an 8-month-old infant presenting with hypocalcemia and Epstein-Barr virus infection: acute myocarditis? Or primary hypokinetic dilated cardiomyopathy?].

An eight-month-old was admitted for acute congestive heart failure with fever. The respective parts played by hypocalcemia (due to vitamin-D deficiency rickets) and acute Epstein-Barr virus infection are discussed. Hypocalcemia was sufficiently marked to induce heart failure per se but replenishment of calcium stores was followed by only partial improvement in cardiac manifestations. Initial management was difficult because of the risks associated with concomitant administration of calcium and digitalis. After eighteen months during which the patient's status remained stable, evaluation showed that clinical features were consistent with sequelae of acute viral myocarditis. The possibility of primary hypokinetic dilated cardiomyopathy was then considered. Esterified carnitine levels were found to be increased leading to further investigations which outruled mitochondrial cytopathy.

Acute Disease↗
PubMed1990

[Vasomotility of the bronchial circulation in cardiac failure].

The bronchial circulation is a physiological left-to-left shunt; the venous return of the bronchial arteries vascularising the intra-pulmonary bronchi drains directly into the left heart chambers. In cardiac failure, increased left ventricular filling pressures affects the bronchial circulation and causes stasis and congestion. Congestion of the arterial and venous bronchial microcirculation leads to thickening of the bronchial mucosa and submucosa, resulting in a tendency to obstruct small and medium-sized airways. The bronchial circulation can be explored indirectly in cardiac failure by the spirometric response to adrenergic agonists and antagonists administered by inhalation: bronchial vasomotor phenomena explain the symptomatology of cardiac asthma and also seem to play a role in the genesis of the dyspnoea of effort in patients with cardiac failure.

Bronchi↗
PubMed1990

Evidence of mitochondrial impairment during cardiac allograft rejection.

NADH laser fluorimetry and mitochondrial oxigraphy were used to study myocardial oxidative energy metabolism during cardiac allograft rejection. Heterotopic cardiac transplantation was performed on Lewis rats; allografts (with Fischer rat donors) were compared with isografts (with Lewis rat donors). In vivo and in vitro assays were performed six days after transplantation. Myocardial NADH fluorescence was recorded in vivo from grafted hearts, at baseline; during brief, complete ischemia; and during reperfusion. Oxygen consumption of mitochondria isolated from both native and grafted hearts was determined. Neither baseline levels nor maximum ischemic levels of NADH fluorescence (F0 = k[NADH]) were found to be significantly different between allografts (0.45 +/- 0.05 to 0.87 +/- 0.10) and isografts (0.45 +/- 0.04 to 1.11 +/- 0.05). During recovery, the rate of fluorescence decrease was significantly lower in allografts than in isografts (0.024 +/- 0.001 vs. 0.038 +/- 0.002 delta F0.s-1, P less than 10(-3], indicating a lower rate of NADH reoxidation. In the presence of malate and glutamate substrates, mitochondrial O2 consumption was significantly lower in allografts than in isografts (30 +/- 9 vs. 100 +/- 15 nanoatoms O2. min-1.mg prot-1, P less than 10(-2]. These results indicate that mitochondrial oxidative metabolism was impaired during the rejection process. Such energy production disturbances may contribute to the dysfunction of rejecting hearts.

Animals↗
PubMed1988

Systemic alkalosis as a provocative test for coronary artery spasm in patients with infrequent resting chest pain.

Systemic alkalosis was used to detect coronary spasm in 237 patients with infrequent, resting, angina-compatible chest pain. The provocative test was performed without previous coronary arteriography but only in patients with negative submaximal exercise test results. Rapid infusion of alkaline solution followed by maximal hyperventilation raised arterial pH above the 7.65 value necessary for diagnostic significance in 196 (83%) patients. In 24 (12%) of these patients the provocative test induced significant ischemic ST segment changes. In all patients with a positive response, coronary artery disease, which was predominantly vasospastic (19 patients) or atheromatous with a vasospastic contribution (five patients), was demonstrated by coronary arteriography followed, if necessary, by ergot derivative injection. Chest pain and ECG changes were always reversed within 5 minutes by intravenous nitroglycerin. Coronary arteriography was not performed in all patients with a negative response; therefore, the sensitivity of the procedure could not be assessed. However, 36 patients with a negative response to hyperventilation underwent coronary arteriography; 33 (92%) had normal arteriograms and a negative response to ergot derivatives. Hyperventilation appears to be a safe and specific diagnostic procedure in a subset of patients in whom the probability of coronary artery disease may not be judged sufficient to warrant coronary arteriography as a primary diagnostic approach.

Adult↗
PubMed1988

Congenital valvular aortic stenosis in adults.

Based on a study of 20 patients operated on between the ages of 21 and 38 for congenital valvular aortic stenosis, the distinguishing features of congenital aortic valvular stenosis in adults are reviewed: valvular calcification (75%), valvular dome rarely present (10%), usually moderate cardiac disability (70%), diminished or inaudible second heart sound (50%), associated diastolic murmur (75%), electrocardiographic left ventricular hypertrophy (70%), and an infrequent protosystolic click (30%). Surgery is necessary for symptomatic patients. If patients are asymptomatic, surgery is decided after measuring the left ventricle-aortic pressure gradient by continuous Doppler wave study, or by cardiac catheterization. If surgery is not performed, a regular follow-up is necessary because stenosis can evolve. Valvular replacement by a mechanical valve is preferable. Even if the aortic valve is not calcified and a simple commissurotomy is technically possible, it is only a palliative method with unsatisfactory results and an annual mortality rate after surgery of 1%.

Adult↗