996 resultados para Holmes, Oliver Wendell
Resumo:
Non-typable Haemophilus influenzae (NTHi) is a Gram negative pathogen that causes acute respiratory infections and is associated with the progression of chronic respiratory diseases. Previous studies have established the existence of a remarkable genetic variability among NTHi strains. In this study we show that, in spite of a high level of genetic heterogeneity, NTHi clinical isolates display a prevalent molecular feature, which could confer fitness during infectious processes. A total of 111 non-isogenic NTHi strains from an identical number of patients, isolated in two distinct geographical locations in the same period of time, were used to analyse nine genes encoding bacterial surface molecules, and revealed the existence of one highly prevalent molecular pattern (lgtF+, lic2A+, lic1D+, lic3A+, lic3B+, siaA−, lic2C+, ompP5+, oapA+) displayed by 94.6% of isolates. Such a genetic profile was associated with a higher bacterial resistance to serum mediated killing and enhanced adherence to human respiratory epithelial cells.
Resumo:
Tetracyclines exhibits activity to a broad range of Gram-negative and Gram-positive bacteria and this fact allied to the low toxicity, low cost, and the advantage of administration by oral route led to their indiscriminate use, which caused the appearance of bacterial resistance to these agents, wich has restricted its clinical utility, though new applications have emerged. On the other hand, the glycylcyclines, semi-synthetic products are similar to tetracyclines, which are active against many bacteria resistant to tetracycline and other classes of antibiotics. The purpose of this paper is to give an overview of this important class of antibiotics focusing on its coordination chemistry and possible applications.
Resumo:
Antibiotic resistance has been growing at an alarming rate and consequently the arsenal of effective antibiotics against Gram-negative and Gram-positive bacteria has dropped dramatically. In this sense there is a strong need to produce new substances that not only have good spectrum of activity, but having new mechanisms of action. In this regard, this paper emphasizes the coordination of metals to antibiotics as a strategy for reversing antibiotic resistance and production of new drugs, with a special focus on quinolones, fluoroquinolones, sulfonamides and tetracyclines.
Resumo:
The triterpenoids oleanolic (OA) and ursolic (UA) acids show non-selective antiinflamatory activity in vitro for cyclooxygenase (COX) isoforms. 3D conformations of OA and UA, with three possible orientations (1, 1' and 2) in the active site of isoforms COX, obtained by docking, were submitted to molecular dynamics. The results show that orientation 2 of the OA in COX-2 is more favorable because orientation 1 moved away from the active site. The carboxylate group of OA interact by hydrogen bonds with Ser353 and with Phe357 and Leu359, mediated by water, while hydroxyl in C-3 interact by hydrogen bond, mediated by water, with Tyr385.
Resumo:
Here we report the validation of a derivatization method that makes use of fluorescamine as a selective reactant for the quantitative analysis of peptide and protein drugs in the dissolution profile from depot formulations. Typical current methods require separation of the nano/microparticles and time-consuming chromatographic runs. In this study we report a method which can be conducted without the need for complete physical separation of the particles or removal of the unreacted probe. This method was used here for the analysis of the release profile of octreotide in a depot formulation, with results in excellent agreement with reported chromatographic assays.
Resumo:
This report describes a study about the feasibility of using a conventional digital camera, a cell-phone camera, an optical microscope, and a scanner as digital image capture devices on printed microzones. An array containing nine circular zones was drawn using graphics software and printed onto transparency film by a laser printer. Due to its superior analytical performance, the scanner was chosen for the quantitative determination of Fe2+ in pharmaceutical samples. The data achieved using scanned images did not differ statistically from those attained by the reference spectrophotometric method at the confidence level of 0.05.
Resumo:
Kirjallisuusarvostelu
Resumo:
O estudo químico das cascas de Ochroma lagopus Swartz levou ao isolamento e ou, identificação de uma mistura de ácidos graxos e triacilglicerídeos, de b-sitosterol (1), estigmasterol (2), daucosterol (3), estigmasterol-3-O-b-D-glicosídeo (4) e manitol (5).
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Este artigo descreve a síntese e caracterização de um novo complexo binuclear de paládio (II) contendo o antibiótico oxitetraciclina. O complexo foi caracterizado pelas técnicas usuais de análise. Pela análise do espectro de infravermelho sugerimos que o íon paládio(II) coordena-se no anel A, mais especificamente nos oxigênios da amida e da hidroxila vizinha no anel A e aos oxigênios da carbonila em C11 e da hidroxila em C12.
Resumo:
Kirjallisuusarvostelu