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Full-Text Articles in Medicine and Health Sciences
Characterization Of The Role That Alternative Ribonucleotide Reductases Play In Restoring Replication In The Presence Of Hydroxyurea In Escherichia Coli, Michael Sadek
PSU McNair Scholars Online Journal
DNA replication is essential for cells to grow and divide. Ribonucleotide reductase is an essential enzyme that is responsible for the formation of deoxyribonucleotides that are used in DNA synthesis during replication. Hydroxyurea is a chemotherapeutic agent that is thought to work by specifically inhibiting the ribonuceotide reductase to prevent replication. However, recent studies in E. coli have shown that following an initial period of inhibition, DNA synthesis then recovers in the presence of hydroxyurea, suggesting that the mode of death and cellular response to hydroxyurea is more complex than originally proposed. The E.coli genome encodes three ribonucleotide reductases that …
Serum Pharmacokinetics And Tissue Concentrations Of A Newrecrystallized Enrofloxacin Hydrochloride-Dihydrate In Hamsters, Alma Carrascosa, Alejandro De La Peña, Lilia Gutierrez, Hector Sumano
Serum Pharmacokinetics And Tissue Concentrations Of A Newrecrystallized Enrofloxacin Hydrochloride-Dihydrate In Hamsters, Alma Carrascosa, Alejandro De La Peña, Lilia Gutierrez, Hector Sumano
Turkish Journal of Veterinary & Animal Sciences
Pharmacokinetics (PK), pharmacodynamics (PD), and PK/PD ratios of a new solvate of enrofloxacin (enrofloxacin hydrochloride-dihydrate; enro-C), were studied in hamsters. Enrofloxacin from Baytril1397904493 5% (enroR) served as the reference preparation. Two groups of 60 Syrian golden hamsters were intramuscularly injected individually with 10 mg/kg of enroR or with enro-C. Tissue and serum samples were obtained for 72 h; enrofloxacin concentrations were determined by HPLC with UV detection. Ninety percent minimum inhibitory concentrations (MIC90) were determined for strains of methicillin-resistant Staphylococcus aureus, Leptospira interrogans, and Escherichia coli. All PK variables were statistically different between groups (P < 0.01). CMAX of enrofloxacin for enro-C was 17.3 μg/mL and it was 2.6 μg/mL for enroR. AUC was considerably higher for enro-C (459.2 μg/mL h vs. 19.9 μg/mL h). There were no statistically significant differences in MIC90 values between enroR and enro-C. Tissue concentrations of enro-C in all cases were higher and remained above the MIC for longer periods than those of enroR. Relevant PK/PD ratios for enrofloxacin (AUC/MIC ? 125 and CMAX > MIC = 10-12) are consequently …