Papers by Apostolos Georgopoulos
International Journal of Antimicrobial Agents, 2003
We employed an in-vivo pharmacokinetic/in-vitro pharmacodynamic method to simulate bacterial kill... more We employed an in-vivo pharmacokinetic/in-vitro pharmacodynamic method to simulate bacterial killing in plasma and the interstitium of skeletal muscle tissue after intravenous administration of 2 g of cefpirome and 8 g of fosfomycin alone and in combination to patients with sepsis. Interstitial antimicrobial concentrations were determined by use of in-vivo microdialysis. CFU/ ml of Staphylococcus aureus (ATCC 29213) and Pseudomonas aeruginosa (clinical isolate) decreased by approximately 2 log 10 for plasma and muscle tissue 6 h after cefpirome and fosfomycin administration compared with the baseline, respectively. The simulation of plasma and tissue pharmacokinetics for the combined administration of these antibiotics resulted in complete eradication of S. aureus within 5 h after drug exposure. No bacterial re-growth occurred in any of the simulations within 6 h. The invitro simulation of in-vivo plasma and tissue pharmacokinetics of cefpirome and fosfomycin has shown that both antimicrobial agents kill S. aureus and P. aeruginosa strains effectively after single dose administration. This effect was most pronounced by the combined use of these antimicrobial agents. Therefore, this data corroborates antimicrobial strategies of simultaneous administration of cefpirome and fosfomycin in patients with severe soft tissue infection. #
Infection, 1980
The fluids from diffusion chambers implanted in soft tissue and kidneys of rabbits were analysed ... more The fluids from diffusion chambers implanted in soft tissue and kidneys of rabbits were analysed for total protein, albumin, enzymes, ions, glucose, creatinine, urea, uric acid, bilirubin and cholesterol. These date were compared with the corresponding values in plasma. Our data for chamber fluid are in good agreement with data reported for interstitial fluids. The composition of the kidney chamber fluid is nearly constant from three to ten weeks after implantation. The low urea, uric acid and creatinine concentrations indicate that the chamber is not located in the urine collecting area of the kidney. Three days after subcutaneous implantation of chambers, the fluid contains less protein than plasma but has an equal concentration of ions, thus meeting the principal requirements for interstitial fluid. There are indications that the healing process lasts up to ten days after the surgical implantation. In order to examine the permeability of the diffusion chambers, the equilibration half-life times of antibiotics and substances of high and low molecular weights were determined in vitro.
Infection, 1980
A method for collecting soft tissue interstitial fluid in experimental animals for the measuremen... more A method for collecting soft tissue interstitial fluid in experimental animals for the measurement of antibiotic concentrations is described. Diffusion chambers with permeable membranes of 0.45 micron porosity were implanted subcutaneously for four days in order to determine simultaneous concentrations of ampicillin and clindamycin in serum and chamber fluid after perioral administration in rabbits and of oxytetracycline after intravenous injection in dogs. The results are discussed in view of findings from other investigators using different types of tissue cages.
Clinical pharmacology and therapeutics, 1996
Cefpirome is a cephalosporin eliminated primarily by kidneys that requires dosage reduction in pa... more Cefpirome is a cephalosporin eliminated primarily by kidneys that requires dosage reduction in patients with renal failure. The pharmacokinetic parameters were studied in 10 patients with end-stage renal disease who were receiving hemodialysis. Repeated intravenous administration of 2 gm cefpirome three times a week resulted in trough levels of 12.2 +/- 5.4 micrograms/ml and peak serum concentrations of 99.6 +/- 82.1 micrograms/ml. After 3 1/2 hours of hemodialysis with polysulfone high-flux membranes, 62.3% +/- 23.3% of cefpirome was removed. The interdialytic half-life was 9.35 +/- 0.99 hours, and the intradialytic half-life was 2.02 +/- 0.7 hours.
Infection, 1994
... Mycobacwrium tuberculosis in Japan. Rev. Infect, Dis. 3 (1981) 997-1007. 7. Good, RC, Snider,... more ... Mycobacwrium tuberculosis in Japan. Rev. Infect, Dis. 3 (1981) 997-1007. 7. Good, RC, Snider, DE: Isolation of nontuberculous mycobacteria in the United States, 1980. J. Infect. Dis. 146 (1982) 829-833. 8. Levine, B., Chaisson ...
The Journal of the American Dental Association, Jul 31, 2007
The use of the erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser has become acc... more The use of the erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser has become accepted in the field of cavity preparation. The development of miniaturized and flexible fiber tips has allowed this device to be used in endodontics. The authors conducted an in vitro study to assess the effects of Er,Cr:YSGG laser irradiation on root canals. The authors inoculated root canals with two bacteria, laser irradiated them at two power settings and subjected them to a quantitative microbiological evaluation. They used scanning electron microscopy (SEM) to assess morphological changes in endodontically processed and laser-irradiated root canal walls. They measured temperature increases on the root surface to determine possible thermal side effects. The bacteriological evaluation revealed a disinfecting effect in the root dentin samples that was dependent on the output power but not specific for the bacterial species investigated. SEM showed the removal of the smear layer from the root canal walls and the exposure of dentinal tubules. The temperature rise during irradiation was moderate when standardized power settings were used. The Er,Cr:YSGG laser can be used to eliminate bacteria in root canals. It also effectively removes smear layer and debris from the canal wall. Practitioners can use the Er,Cr:YSGG laser to prepare root canals for endodontic therapy.
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Papers by Apostolos Georgopoulos