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Biomedical subjects

B LeBlanc

Publications and source records attributed to B LeBlanc.

At least 19 recordsLinked to original sources
PubMed2001

Observation of compressional Alfvén modes during neutral-beam heating on the national spherical torus experiment.

Neutral-beam-driven compressional Alfvén eigenmodes at frequencies below the ion cyclotron frequency have been observed and identified for the first time in the National Spherical Torus Experiment. The modes are observed as a broad spectrum of nearly equally spaced peaks in the frequency range from approximately 0.2omega(ci) to approximately 1.2omega(ci). The frequency has a scaling with toroidal field and plasma density consistent with Alfvén waves. The modes have been observed with high bandwidth magnetic pickup coils and with a reflectometer.

Journal Article↗
PubMed1997

In-vitro activity of trovafloxacin against clinical bacterial isolates from patients with cancer.

The antibacterial activity of trovafloxacin was compared with that of ciprofloxacin, levofloxacin, ofloxacin, sparfloxacin and norfloxacin against bacterial isolates from patients with cancer. In general, the activity of trovafloxacin was comparable to that of ciprofloxacin, levofloxacin and sparfloxacin against most Gram-negative isolates tested (minor differences in the activity of each agent against individual species were seen) and it was the most active agent tested against Stenotrophomonas maltophilia, inhibiting 80% of these isolates at <2.0 mg/L. Trovafloxacin was also the most active agent tested against Gram-positive organisms, including ciprofloxacin-susceptible strains and most ciprofloxacin- and methicillin-resistant staphylococci and enterococci. It was much more active than ciprofloxacin against streptococci, including Streptococcus pneumoniae and the viridans streptococci, and was also active against Bacillus cereus and Listeria monocytogenes, inhibiting all isolates at a concentration of <0.5 mg/L.

Anti-Infective Agents↗
PubMed1996

In-vitro activity of ramoplanin (a novel lipoglycopeptide), vancomycin, and teicoplanin against gram-positive clinical isolates from cancer patients.

The in-vitro activities of ramoplanin, vancomycin, and teicoplanin against Gram-positive organisms isolated from cancer patients were determined. Ramoplanin was the most active agent tested inhibiting all isolates at a concentration of < or = 0.5 mg/L. Although all isolates were also susceptible to vancomycin and teicoplanin, their activities were surpassed by that of ramoplanin. The activity of teicoplanin was moderately better than that of vancomycin against Bacillus cereus, Enterococcus faecium, Listeria monocytogenes, methicillin-resistant Staphylococcus aureus, and most streptococcal isolates, and was comparable to vancomycin for the remainder of the isolates tested.

Anti-Bacterial Agents↗
PubMed1994

In vitro activity of FK-037, a novel parenteral cephalosporin, against bacterial isolates from neutropenic cancer patients.

The in vitro activity of FK-037, a novel parenteral cephalosporin, was compared to that of ceftazidime, aztreonam and piperacillin (agents often used in empiric regimens in cancer patients) against recent bacterial isolates from patients with cancer. FK-037 was either equal to or 2 to 16-fold more active than the comparative agents against members of the Enterobacteriaceae. It was also active against Acinetobacter spp., Aeromonas spp., Pseudomonas aeruginosa, and other Pseudomonas spp. Xanthomonas maltophilia and Alcaligenes denitrificans were relatively resistant to all four agents. FK-037 was also 4 to 16-fold more active against most gram-positive organisms (including some methicillin-resistant staphylococci) than was ceftazidime. Enterococcus spp., Listeria monocytogenes and Staphylococcus haemolyticus were relatively resistant to FK-037 and ceftazidime. Overall, FK-037 has a broad antimicrobial spectrum that includes the majority of gram-positive and gram-negative isolates.

Aztreonam↗
PubMed1994

Susceptibilities of bacterial isolates from patients with cancer to levofloxacin and other quinolones.

The antibacterial activity of levofloxacin was compared with those of ofloxacin and ciprofloxacin against bacterial isolates from patients with cancer. In general, levofloxacin was as active or was twofold more active than ofloxacin and was two- to fourfold less active than ciprofloxacin against most gram-negative pathogens. Against Pseudomonas aeruginosa, ciprofloxacin was the most active agent tested (MIC for 90% of isolates tested, 1.0 microgram/ml). Overall, all three agents had similar activities against gram-positive organisms and were moderately active against methicillin-susceptible Staphylococcus aureus and coagulase-negative staphylococci, Streptococcus species, and Enterococcus species.

Anti-Infective Agents↗
PubMed1993

In vitro activities of antimicrobial agents against clinical isolates of Flavimonas oryzihabitans obtained from patients with cancer.

We evaluated the in vitro activities of 21 different antimicrobial agents against nine clinical isolates of Flavimonas oryzihabitans obtained from patients with cancer. The organisms were susceptible to most agents commonly used for the empiric therapy (aminoglycosides, ureidopenicillins, extended-spectrum cephalosporins, monobactams, and carbapenems) and prevention of infections (quinolones and trimethoprim-sulfamethoxazole) in this patient population.

Anti-Bacterial Agents↗
PubMed1992

In vitro activity of Ro 23-9424, a dual-action antibacterial agent, against bacterial isolates from cancer patients compared with those of other agents.

The in vitro activity of Ro 23-9424 against bacterial isolates from patients with cancer was compared with those of fleroxacin, ciprofloxacin, cefoperazone, and ceftazidime. Ro 23-9424 inhibited the majority of the members of the family Enterobacteriaceae and all Aeromonas isolates at a concentration of less than or equal to 1.0 micrograms/ml. It was also active against Acinetobacter spp. and Haemophilus influenzae, including beta-lactamase-producing strains. The MIC for 90% of isolates (MIC90) of Pseudomonas aeruginosa was 16.0 micrograms/ml. All group A and B streptococci were inhibited by less than or equal to 0.25 micrograms/ml, and 90% of group G streptococci and Streptococcus pneumoniae were inhibited by 1.0 micrograms/ml. All methicillin-susceptible strains of Staphylococcus aureus and 60% of methicillin-resistant strains were susceptible to 2.0 micrograms of Ro 23-9424 per ml, whereas the MIC90 for Staphylococcus epidermidis and Staphylococcus hominis isolates was 4.0 micrograms/ml. Staphylococcus haemolyticus and Enterococcus spp. were less susceptible; MIC90s for them were 16.0 and 32.0 micrograms/ml. Ro 23-9424 has a broad antibacterial spectrum and potential utility for therapy of infections in cancer patients.

Anti-Infective Agents↗
PubMed1991

In vitro activity of cefpodoxime against bacterial isolates obtained from patients with cancer.

The in vitro activity of cefpodoxime, an oral cephalosporin ester, against 792 bacterial isolates representing 36 species was evaluated in comparison to that of ciprofloxacin and trimethoprim/sulfamethoxazole (TMP/SMX). Cefpodoxime inhibited the majority of Streptococcus spp., Haemophilus influenzae and Proteus mirabilis at a concentration of less than or equal to 0.12 microgram/ml. It was also active against Citrobacter diversus, Escherichia coli, Klebsiella spp., Proteus vulgaris, Serratia marcescens and methicillin-susceptible Staphylococcus aureus isolates. Overall, cefpodoxime appeared to be less active than ciprofloxacin and TMP/SMX against many pathogens common in cancer patients.

Bacteria↗
PubMed1990

Comparative in vitro activity of the new erythromycin derivative dirithromycin against gram-positive bacteria isolated from cancer patients.

The in vitro activity of dirithromycin (LY-237216), a new macrolide erythromycin derivative, was compared to that of four other agents (clarithromycin, erythromycin, roxithromycin, clindamycin) against 334 gram-positive isolates obtained from cancer patients. Dirithromycin was similar in potency and antimicrobial spectrum to the other agents tested. It was very active against beta-haemolytic streptococci and Streptococcus pneumoniae, and moderately active against penicillin and methicillin susceptible Staphylococcus aureus, Bacillus spp., Listeria monocytogenes and Corynebacterium jeikeium. Erythromycin resistant organisms were also resistant to dirithromycin.

Anti-Bacterial Agents↗
PubMed1990

In-vitro activity of PD 117 596, a new quinolone, against bacterial isolates from cancer patients.

The in-vitro activity of PD117 596, a new 4-quinolone antimicrobial agent was compared with that of ciprofloxacin against 798 Gram-positive and Gram-negative distinct isolates from cancer patients. PD117 596 was found to have a broad antimicrobial spectrum with excellent activity against the Enterobacteriaceae (MIC90 0.03 mg/l) Acinetobacter spp. (MIC90 0.25 mg/l), Aeromonas spp. (MIC100 0.06 mg/l) and Pseudomonas spp. including Ps. aeruginosa (MIC90 0.5 mg/l). It was also extremely active against Gram-positive micro-organisms particularly Staphylococcus spp. (including methicillin-resistant and coagulase-negative isolates) Bacillus spp. and streptococci. PD117 596 had lower minimal inhibitory concentrations against most isolates tested than ciprofloxacin, the most active currently available 4-quinolone.

Anti-Infective Agents↗
PubMed1990

In vitro activity of sparfloxacin (CI-978; AT-4140) against clinical isolates from cancer patients.

The in vitro activity of sparfloxacin, a new quinolone, was compared with those of ciprofloxacin and fleroxacin against gram-positive and gram-negative bacteria, greater than 90% of which were isolated from blood culture specimens of cancer patients. Sparfloxacin was extremely active against Acinetobacter species, Aeromonas hydrophila, Citrobacter diversus, Enterobacter species, Escherichia coli, Klebsiella species, Proteus vulgaris, and Serratia marcescens (inhibiting greater than 90% of these isolates at a concentration of 0.5 microgram/ml) and moderately active against Pseudomonas species, other Proteus species, and Citrobacter freundii. Sparfloxacin inhibited greater than 90% of staphylococci (including methicillin-resistant and coagulase-negative strains) at a concentration of 0.12 microgram/ml and greater than 90% of streptococci (including Streptococcus pneumoniae) at a concentration of 1.0 microgram/ml. It was also active against Bacillus cereus, Enterococcus species, and Corynebacterium jeikeium, organisms that have become fairly common in cancer patients.

Anti-Infective Agents↗
PubMed1990

In vitro activity of PD127,391, a new quinolone against bacterial isolates from cancer patients.

The in vitro activity of PD127,391, a new 4-quinolone, was compared to that of ciprofloxacin against common clinical bacterial isolates from patients with cancer. PD127,391 was found to have a broad antimicrobial spectrum with excellent activity against gram-positive isolates (including multidrug-resistant organism such as Corynebacterium jeikeium, Enterococcus faecalis, Enterococcus faecium, methicillin-resistant Staphylococcus aureus and coagulase-negative Staphylococcus spp.). It was also extremely active against gram-negative bacilli including Pseudomonas aeruginosa. Against organisms such as Achromobacter xylosoxidans, Acinetobacter spp. and Xanthomonas maltophilia, which are frequently resistant to a variety of antimicrobial agents, PD127,391 exhibited good activity, inhibiting all such isolates at a concentration of 0.5 micrograms/ml. Overall, PD127,391 was far more potent than ciprofloxacin against gram-positive isolates and slightly more active against gram-negative isolates. No bacterium that we examined needed more than 2 micrograms/ml of PD127,391 for inhibition.

Anti-Infective Agents↗
PubMed1989

In-vitro activity of PD 117558, a new quinolone against bacterial isolates from cancer patients.

The in-vitro activity of PD 117558, a new quinolone antimicrobial agent, was compared to that of four other quinolones, imipenem and ceftazidime against a variety of Gram-positive and Gram-negative isolates from cancer patients. PD 117558 was found to have a broad antimicrobial spectrum with excellent activity against all Gram-positive isolates (including methicillin-resistant Staphylococcus aureus, coagulase-negative staphylococci, Streptococcus faecalis and Group JK-corynebacteria). It was also extremely active against Gram-negative bacilli with the exception of Pseudomonas aeruginosa against which ciprofloxacin was more active. Fleroxacin was slightly less active and S-25930 and S-25932 considerably less active than PD 117558. PD 117558 also had lower minimal inhibitory concentrations for most organisms tested than either imipenem or ceftazidime.

4-Quinolones↗