Drugs online research references
Pediatr Infect Dis. 1985 Sep-Oct;4(5):491-5.
Role of beta-lactamase-producing bacteria in the failure of penicillin to eradicate group A streptococci.
Brook I.
Ninety-eight children who had acute tonsillitis due to Group A beta-hemolytic streptococci were treated for 10 days with orally administered penicillin B, potassium. Surface tonsillar cultures were obtained before therapy, at the end of therapy and 10, 21 and 42 days after termination of therapy. The cultures obtained before and after completion of treatment were processed for aerobic and anaerobic organisms, while the other cultures were processed only for Group A beta-hemolytic streptococci. On the basis of bacteriologic results 62 patients were considered "cured" (Group A) and 36 "failed" (Group B) following therapy. Before therapy 18 isolates of beta-lactamase-producing organisms (BLPO) were detected in 16 (26%) children in Group A; after therapy 30 BLPO were detected in 19 (30%) children. In contrast, before therapy 40 BLPO were recovered from 25 (69%) children in Group B; this number increased to 62 BLPO in 31 (86%) of those children. The study demonstrates an association between failure to eradicate Group A beta-hemolytic streptococci and the presence of aerobic and anaerobic BLPO.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=3931058&dopt=Abstract
Biotechnol Bioeng. 2000 May 5;68(3):285-97.
Dynamic biochemical reaction process analysis and pathway modification predictions.
Conejeros R, Vassiliadis VS.
Department of Chemical Engineering, Cambridge University, Pembroke Street, Cambridge CB2 3RA, UK.
Recently, the area of model predictive modification of biochemical pathways has received attention with the aim to increase the productivity of microbial systems. In this study, we present a generalization of previous work, where, using a sensitivity study over the fermentation as a dynamic system, the optimal selection of reaction steps for modification (amplification or attenuation) is determined. The influence of metabolites in the activity of enzymes has also been considered (through activation or inhibition). We further introduce a new concept in the dynamic modeling of biochemical reaction systems including a generalized continuous superstructure in which two artificial multiplicative terms are included to account for: (a) enzyme overexpression or underexpression (attenuation or amplification) for the whole enzyme pool; and (b) modification of the apparent order of a kinetic expression with respect to the concentration of a metabolite or any subset of metabolites participating in the pathway. This new formulation allows the prediction of the sensitivity of the pathway performance index (objective function) with respect to the concentration of the enzyme, as well as the interaction of the enzyme with other metabolites. Using this framework, a case study for the production of penicillin V is analyzed, obtaining the most sensitive reaction steps (or bottlenecks) and the most significant regulations of the system, due to the effect of concentration of intracellular metabolites on the activity of each enzyme. Copyright 2000 John Wiley & Sons, Inc.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=10745197&dopt=Abstract
J Chromatogr. 1985 Dec 4;348(2):379-87.
Studies on residual antibacterials in foods. IV. Simultaneous determination of penicillin G, penicillin V and ampicillin in milk by high-performance liquid chromatography.
Terada H, Sakabe Y.
A rapid and simple method for the simultaneous determination of penicillin G (PCG), penicillin V (PCV) and ampicillin (ABPC) in milk is described. The retention behaviour of these beta-lactam antibiotics in reversed-phase liquid chromatography with mobile phases containing sodium alkylsulphonate was studied. Good separations were obtained with methanol-water-0.2 M phosphate buffer (pH 4.0) (5:13:2) containing 11 mM sodium 1-heptanesulphonate and a LiChrosorb RP-18 column. The sample was pre-treated with a Sep-Pak C18 cartridge. The peaks corresponding to each beta-lactam antibiotics can be confirmed with the treatment using penicillinase. The recoveries from milk fortified with sodium PCG, potassium PCV and ABCP at levels of 0.5 and 0.1 micrograms/g each were generally better than 87% and the relative standard deviations were 1.17-4.98%. The detection limits corresponded to 0.03 microgram/g of these beta-lactam antibiotics in milk.
online pharmacy ref source: www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=3935654&dopt=Abstract
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