Aminoglycosides confirmation

The in vivo protective activity of rifaximin was studied in mice, infected experimentally by intraperitoneal inoculation of S. aureus Colliva and compared to that of rifampicin (a systemic rifamycin) and gentamicin (a poorly absorbed aminoglycoside) [74]. After oral administration, only rifampicin was effective whereas the other two compounds were inactive at doses up to 10 mg/kg. However, when injected subcutaneously, rifaximin displayed a good therapeutic efficacy (table 2). While confirming its antibacterial activity, these results clearly indicate that rifaximin, like gentamycin, is poorly absorbed after oral administration. 

Ramakrishnan and co-workers 3-A crystal structures of two different aminoglycosides (paromomycin and streptomycin) bound to the 30S subunit laid to rest much of the debate concerning the binding mode of aminoglycoside antibiotics. Paromomycin was found bound to the major groove of helix 44 (H44), confirming mutagenesis studies that had been carried out previously. ... 

In Australia, the general antimicrobial screen is performed on kidney and is able to detect -lactam, aminoglycoside, tetracycline, and macrolide antimicrobials and to identify the class of antimicrobial compound present. Where the screen test identifies a class of compounds, confirmation and quantitation are done by the specific HPLC or gas chromatographic (GC) method appropriate for the class of antimicrobial. 

L.G. McLaughlin, J.D. Henion, P.J. Kijak, Multi-residue confirmation of aminoglycoside antibiotics and bovine kidney by LC-ESI-MS-MS, Biol. Mass Spectrom., 23 (1994) 417. 

LLC-PK] cells appear to be an acceptable model for the study of aminoglycoside toxicity due to the following observations (1) A recent study confirmed in vivo observations that gentamicin was more toxic to LLC-PKi monolayers when exposed at the apical side, which... 

The incidence of aminoglycoside nephrotoxicity rises with advancing age from 7% in patients under age 30 to 15% in patients over 70 years of age [16]. It is likely that dosage may be excessive in older patients based on overestimates of drug excretory capacity by insensitive renal function tests such as the serum urea nitrogen or serum creatinine. This age effect has been confirmed in a retrospective stepwise discriminant analysis of 214 patients in randomized prospective trials [17]. The mechanism of this age effect is unclear since experimental studies show a decrease in drug uptake in older animals compared to similarly dosed younger animals [18]. 

Most strains of Pseudomonas aeruginosa are resistant to various antibiotics, and the natural resistance, at least to aminoglycosidic antibiotics, has been confirmed as being related to formation of enzymes that inactivate these antibiotics. The presence of such an enzyme in Pseudomonas aeruginosa was first reported by Umezawa and coworkers. ... 

The quantification and confirmation of aminoglycoside antibiotics (Eig. 7.8) at trace residue concentrations in animal tissues has long been a challenge because of the high polarity of the analytes and lack of a suitable chromophore for detection. MRLs are often relatively high for example, for neomycin, MRLs range from 500 to 10000 p-g/kg in Australia in line with the revised MRLs established by CAC, from 500 to 5000 pg/kg in the EU and from 150 to 7200 pg/kg as tolerances in the United States of America. ... 

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