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Biomedical subjects

M Cluzel

Publications and source records attributed to M Cluzel.

At least 37 records · Page 2Linked to original sources
PubMed1987

Enhanced alveolar cell luminol-dependent chemiluminescence in asthma.

Alveolar macrophages (AM) appear to be one type of cells of the bronchial inflammation often involved in patients with asthma. These cells were demonstrated to generate highly reactive toxic species of oxygen in many pulmonary disorders; however, this was never demonstrated in asthma. The respiratory burst of bronchoalveolar lavage AM was studied in 12 subjects with asthma and in five control subjects by luminol-enhanced chemiluminescence (Cl). Both in subjects with asthma and in healthy subjects, the maximal value of Cl was obtained after 10 to 13 minutes of stimulation by opsonized zymozan. Baseline values and maximal Cl of AM values were significantly increased (p less than or equal to 0.03 and p less than or equal to 0.01) in subjects with asthma. There was a significant (p less than or equal to 0.01) correlation between maximal Cl of AM and the severity of asthma, assessed by a clinical score defined by Dr. K. Aas. The percentage of bronchoalveolar lavage eosinophils was significantly correlated (p less than or equal to 0.01) for all the subjects with the peak of CL of AM. This study suggests the role of toxic oxygen species in the bronchial inflammation in asthma.

Adult↗
PubMed1987

[Oxygen free radicals and bronchial asthma].

Oxygen free radicals are released generally by many cells during phagocytosis and cell activation. In asthmatics, some experimental evidence indicates that oxygen free radicals may be considered to be chemical mediators of anaphylaxis. They are released by macrophages, eosinophils and neutrophils, the cells that are found in bronchoalveolar lavage. They may explain some pathological changes, such as hardening of the airways, bronchial hyper-reactivity and inflammation. Therapeutic implications are discussed.

Adolescent↗
PubMed1987

[Value of x-ray CT used in thin sections for evaluating sarcoidosis. Apropos of 57 cases. Comparison with other methods].

The authors have staged by CT 57 cases of sarcoidosis. In all cases CT has given superior semiologic pattern in comparison with plain-films which are the classical baseline references (Turiaf)...up to date. 30% of type I sarcoidosis are staged as type II by thin-section CT slices. This radio-clinic evaluation must be continued on months to find if this group is an homogeneous one in the prognostic meaning and if cortico-therapy is useful. The authors propose a systematic CT evaluation of sarcoidosis in 1987 and a CT actualization of the radiologic classification of the disease.

Evaluation Studies as Topic↗
PubMed1986

[In vitro comparative study of piperacillin-aminoglycosides combinations against Enterococci and Enterobacteriaceae].

The hundred and ninety-two combinations were tested against 17 strains chosen from the results of MIC determination (disc method): 5 enterococci exhibiting low level resistance (r) or high level resistance (R) to streptomycin (S) and gentamicin (G): 2 strains Sr Gr, 2 strains SR Gr and 1 strain Sr GR; 12 enterobacteria chosen for their resistance phenotypes to beta-lactams and aminoglycosides and because they are the most frequent clinical isolates: 2 strains Amos Tics Ctns (group 1), 4 strains AmoR Tics CtnR (gr. II), 4 strains AmoR TicR Ctns (gr. III) and 2 strains AmoR TicR CtnR (gr. IV). MIC and MBC were assessed for the 17 strains (Mueller Hinton broth). Combinations were carried out by a checkerboard micromethod. FBC index was calculated for each combination. Against enterococci the 50 combinations were: piperacillin versus ampicillin + aminoglycosides (streptomycin, tobramycin, amikacin, gentamicin, netilmicin). Against enterobacteria piperacillin was combined with different aminoglycosides depending on their resistance phenotypes. These combinations were compared with ticarcillin or mezlocillin or cefotaxime + aminoglycosides (total number 142). The species studied produced different results: with the enterococci Gr synergistic effects (FBC = 0.62-0.75) were rare; additive and indifferent effects were predominant. With the GR strain some antagonistic effects were observed. With the enterobacteria, in groups I and II synergistic effects were frequent and almost equivalent regardless of the beta-lactam chosen. In groups III and IV (TicR) piperacillin MICs were greater than or equal to 128 mg/l and mezlocillin MICs greater than 512 mg/l; the synergistic effects were significant (FBC from 0.25 to 0.62). beta-lactam + amikacin or netilmicin, and especially piperacillin + amikacin, were found to have the most frequent synergistic effects upon the strains tested. Mezlocillin combinations cannot be used clinically; the use of piperacillin combinations requires further discussion. On the other hand, cefotaxime + aminoglycosides combinations are active against those TicR strains.

Aminoglycosides↗
PubMed1986

A comparison of agar dilution, identification of beta-lactamases and disc diffusion methods for assessing the sensitivity to ticarcillin-clavulanic acid.

The in-vitro antibacterial activity of Timentin has been evaluated with a view to proposing valid criteria for sensitivity and resistance. Minimal inhibitory concentrations (MIC) were determined for 284 strains including Enterobacteriaceae, Pseudomonas aeruginosa, Acinetobacter spp., staphylococci and enterococci. The same strains were also used for the determination of inhibition zones around discs containing 75 micrograms ticarcillin and 10 micrograms clavulanic acid, and a straight regression line was drawn correlating MIC with inhibition zones. The bacterial population was subsequently grouped according to the diameters of inhibition zones of the antibiogram for 2427 strains of Enterobacteriaceae classified by phenotypes. The comparison of MICs of Timentin and ticarcillin for these strains shows that for penicillinase-producing strains, the Timentin MIC is lower than for ticarcillin whereas cephalosporinase-producing strains have equal MICs for the two. Finally strains that produce many different beta-lactamases are not affected by the presence of clavulanic acid. These results should make it possible to propose provisional zone diameters for determining sensitivity and resistance to Timentin.

Agar↗
PubMed1986

Resistance to beta-lactams in Enterobacteriaceae: distribution of phenotypes related to beta-lactamase production.

Phenotypes of susceptibility to amoxycillin (Amo), ticarcillin (Tic), cephalothin (Ctn) were determined in 1366 isolates of Enterobacteriaceae by disk method and beta-lactamases were identified in 243 strains belonging to different phenotypes of amoxycillin-resistant strains. AmoR TicR CtnS strains (25%) were penicillinase producers and all of them were susceptible to the combination amoxycillin/clavulanic acid (Amo/CA) and ticarcillin/clavulanic acid (Tic/CA). Amo1/R TicS CtnR strains (12%) were cephalosporinase producers and resistance to Amo/CA was observed, except for Proteus vulgaris. AmoR TicR CtnR strains (18%) often produced two beta-lactamases (penicillinase and cephalosporinase) and they were resistant to Amo/CA; in this group, susceptibility to Tic/CA depends on the nature and the amount of the beta-lactamase produced, except for Serratia marcescens for which antibiotic resistance is probably due to other mechanisms. Tic/CA resistance was mainly found in Serratia marcescens (41%) and Enterobacter cloacae (36%).

Amoxicillin↗
PubMed1986

[In-vitro activity of cefonicid on hospital bacteria. Regression line and proposal for critical values].

Antimicrobial activity of cefonicid, a new second generation cephalosporin, against 315 hospital isolates (4th trimester 1984) was investigated. E. coli and Proteus mirabilis were the most susceptible species. All E. coli strains except one were inhibited at 8 mg/l (modal MIC: 0.5); MICs of all indole + Proteus were 8 mg/l (modal MIC: 0.06). Another group was moderately susceptible: MICs of Klebsiella and Citrobacter ranged from 0.12 to 128 mg/l, but MICs of 50% of these strains were less than or equal to 4 mg/l; MIC was less than or equal to 8 mg/l for 75% of indole + Proteus and Providencia strains; tested Proteus vulgaris were especially resistant (MICs greater than 128 mg/l). Most Enterobacter and Serratia strains showed little susceptibility (modal MIC for both species greater than or equal to 128 mg/l). MICs of all tested Pseudomonas aeruginosa strains were greater than 128 mg/l. 20 of the 24 tested Acinetobacter strains had a MIC of greater than or equal to 128 mg/l. For Staphylococcus aureus, 88% of methicillin-sensitive strains were inhibited by concentrations of 2 to 4 mg/l whereas methicillin-resistant strains were resistant to cefonicid (75%: MIC greater than 64 mg/l). Enterococci were resistant to cefonicid. A correlation curve was established (Enterobacteria and Staphylococci). On the basis of cefonicid's pharmacokinetic characteristics, critical concentrations are proposed.

Bacteria↗
PubMed1986

[In vitro activity of a new 3d-generation cephalosporin, cefodizime, on hospital bacteria].

Minimal inhibitory concentrations (MICs) of cefodizime were evaluated by agar dilution for 746 bacterial strains isolated in two hospitals. For enterobacteriaceae MICs ranged from 0.008 micrograms/ml to more than 128 micrograms/ml (mode MIC: 0.25); mode MICs varied across species, ranging from 0.016 micrograms/ml for Proteus mirabilis to 1 microgram/ml for Citrobacter; MICs ranged from 0.12 to 8 for most Enterobacter and from 1 to 64 for Serratia. The rare cefotaxime-resistant strains, most of which were Citrobacter or Enterobacter, also showed resistance to cefodizime. Cefodizime was noticeably less active against Pseudomonas aeruginosa and Acinetobacter, with MICs ranging from 32 to more than 128. Haemophilus sp. and Gonococci, regardless of beta-lactamase-production status, as well as Neisseria meningitidis, were highly susceptible (MIC less than or equal to 0.008-0.016). Cefodizime was moderately active against methicillin-susceptible Staphylococci (MIC: 2 to 16 micrograms/ml) and failed to inhibit methicillin-resistant strains. Enterococci were slightly susceptible or resistant. Whereas the other Streptococci and Pneumococci had low MICs (0.03-0.12). A fairly wide range of MICs was found for anaerobes, with lower values for Clostridium (0.008 to 1) than for Bacteroids (8 to 128 mu g/ml). Our results show that cefodizime has the same properties as other third-generation cephalosporins: cefotaxime-resistant Enterobacteriaceae strains also exhibit resistance to cefodizime.

Bacteria↗
PubMed1985

[In vitro effect of ceftriaxone on hospital bacteria. Line of regression and critical values].

Antimicrobial activity of ceftriaxone, a new third generation cephalosporin, against hospital isolates was investigated. 312 strains belonging to the most commonly recovered species were studied using the following methods: agar diffusion (disk antibiotic testing), agar dilution (determination of MIC) and dilution in a liquid medium with subculture to agar plates (determination of MBC). Except for a few Citrobacter strains and rare Serratia strains, all Enterobacteriaceae tested proved highly susceptible, with MICs less than or equal to 1 mg/l and mode MICs ranging from 0.003 mg/l (Proteus) to 0.25 mg/l (Enterobacter). MICs ranged from 16 to 32 mg/l for Acinetobacter (mode MICs: 16 mg/l) and 16 to greater than or equal to 128 for Pseudomonas (mode MIC greater than or equal to 128 mg/l). Methicillin-susceptible staphylococci were moderately susceptible to ceftriaxone (MIC: 2 to 8 mg/l) whereas methicillin-resistant staphylococci and enterococci were resistant (MIC greater than or equal to 64 mg/l). Bactericidal activity was excellent: MBC/MIC less than or equal to 2 (except for a few Serratia strains). A correlation curve was established. Given the high serum concentrations of ceftriaxone (achieved with the usual maximal dosage) and its unusually extended half-life (7 to 8 h), the following cutoff concentrations can be proposed: C less than or equal to 4 mg/l, corresponding to greater than or equal to 20 mm: susceptible bacteria C greater than 32 mg/l, corresponding to less than 15 mm: resistant bacteria.

Acinetobacter↗
PubMed1984

[In vitro activity of ceftizoxime on hospital bacteria. Results of a multicenter study].

The susceptibility to ceftizoxime of all bacterial strains isolated from seven university-affiliated hospitals over one month was tested with disk-diffusion technique. Additionally, the MIC of 1937 strains selected at random was evaluated by the agar dilution method. The majority of Enterobacteriaceae are inhibited at a concentration of less than 1 microgram/ml with a mode MIC varying from 0.008 to 0.12 among the various groups. A few Enterobacter and Citrobacter strains are resistant. Little activity was demonstrated by ceftizoxime on Pseudomonas aeruginosa and Acinetobacter sp. (mode MIC 32 and 8 micrograms/ml respectively). Haemophilus sp. (MIC 0.01-0.03) and Neisseria (MIC less than 0,008-0,016) are very susceptible to the drug. The MIC of methicillin-sensitive strains of Staphylococcus aureus varies from 1 to 4 micrograms/ml ; Enterococci are less susceptible, whereas other Streptococci and Pneumococci have low MICs (less than 0.008-0.025). The susceptibility of anaerobic pathogens varies widely between species, and within species ; MIC ranges from 0.008 to 32 micrograms/ml for Clostridium sp. and 0.25 to 128 micrograms/ml for Bacteroides sp.

Bacteria↗
PubMed1984

[Dibekacin in the treatment of urinary infections in the elderly].

Urinary tract infections in the elderly are severe and intractable, often justifying the use of aminoglycosides. We studied the effects of dibekacin in 28 patients, with no vesical catheter, whose average age was 78 +/- 6.1 years. The drug was given for ten days, in an average dose of 2.1 mg/kg/day divided into two injections. Serum concentration was measured after one hour on day 1 and after eight hours on days 1 and 10. Causative pathogens, all susceptible to dibekacin, were: 18 E. coli, 3 Proteus mirabilis, 3 Klebsiella, 1 Enterobacter cloacae, 1 Citrobacter and 2 Staphylococci. MIC and MBC of dibekacin were determined for each microorganism. Dibekacin was discontinued in four cases on day three because of persistent bacteriuria. Ten days after treatment end, 19 patients were cured, 4 had a relapse and 1 was reinfected. Average serum concentration of dibekacin, measured after eight hours, increased from 0.77 +/- 0.48 micrograms/ml on day 1 to 1.78 +/- 1.22 microgram/ml on day 10 (t = 4.42; p less than 0.0005), while, over the same period, there was no significant change in serum creatinine.

Aged↗