120 research outputs found
Improved efficacy of ciprofloxacin administered in polyethylene glycol-coated liposomes for treatment of Klebsiella pneumoniae pneumonia in rats.
Animal and clinical data show that high ratios of the area under the
concentration-time curve and the peak concentration in blood to the MIC of
fluoroquinolones for a given pathogen are associated with a favorable
outcome. The present study investigated whether improvement of the
therapeutic potential of ciprofloxacin could be achieved by encapsulation
in polyethylene glycol (PEG)-coated long-circulating sustained-release
liposomes. In a rat model of unilateral Klebsiella pneumoniae pneumonia
(MIC = 0.1 microg/ml), antibiotic was administered at 12- or 24-h
intervals at twofold-increasing doses. A treatment period of 3 days was
started 24 h after inoculation of the left lung, when the bacterial count
had increased 1,000-fold and some rats had positive blood cultures. The
infection was fatal within 5 days in untreated rats. Administration of
ciprofloxacin in the liposomal form resulted in delayed ciprofloxacin
clearance and increased and prolonged ciprofloxacin concentrations in
blood and tissues. The ED(50) (dosage that results in 50% survival) of
liposomal ciprofloxacin was 3.3 mg/kg of body weight/day given once daily,
and that of free ciprofloxacin was 18.9 mg/kg/day once daily or 5.1
mg/kg/day twice daily. The ED(90) of liposomal ciprofloxacin was 15.0
mg/kg/day once daily compared with 36.0 mg/kg/day twice daily for free
ciprofloxacin; 90% survival could not be achieved with free ciprofloxacin
given once daily. In summary, the therapeutic efficacy of liposomal
ciprofloxacin was superior to that of ciprofloxacin in the free form.
PEG-coated liposomal ciprofloxacin was well tolerated in relatively high
doses, permitting once daily administration with relatively low
ciprofloxacin clearance and without compromising therapeutic efficacy
Mathematical Model of Plasmid-Mediated Resistance to Ceftiofur in Commensal Enteric Escherichia coli of Cattle
Antimicrobial use in food animals may contribute to antimicrobial resistance in bacteria of animals and humans. Commensal bacteria of animal intestine may serve as a reservoir of resistance-genes. To understand the dynamics of plasmid-mediated resistance to cephalosporin ceftiofur in enteric commensals of cattle, we developed a deterministic mathematical model of the dynamics of ceftiofur-sensitive and resistant commensal enteric Escherichia coli (E. coli) in the absence of and during parenteral therapy with ceftiofur. The most common treatment scenarios including those using a sustained-release drug formulation were simulated; the model outputs were in agreement with the available experimental data. The model indicated that a low but stable fraction of resistant enteric E. coli could persist in the absence of immediate ceftiofur pressure, being sustained by horizontal and vertical transfers of plasmids carrying resistance-genes, and ingestion of resistant E. coli. During parenteral therapy with ceftiofur, resistant enteric E. coli expanded in absolute number and relative frequency. This expansion was most influenced by parameters of antimicrobial action of ceftiofur against E. coli. After treatment (>5 weeks from start of therapy) the fraction of ceftiofur-resistant cells among enteric E. coli, similar to that in the absence of treatment, was most influenced by the parameters of ecology of enteric E. coli, such as the frequency of transfer of plasmids carrying resistance-genes, the rate of replacement of enteric E. coli by ingested E. coli, and the frequency of ceftiofur resistance in the latter
The multistate tuberculosis pharmacometric model: a semi-mechanistic pharmacokinetic-pharmacodynamic model for studying drug effects in an acute tuberculosis mouse model
The pathway to murder A social psychological study of the evolution of violence in an industrial dispute
Available from British Library Document Supply Centre-DSC:DX201630 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo
Women's Lives and Women's Health: Using Social Science Research to Promote Better Health for Women
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