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D Barba

Publications and source records attributed to D Barba.

43 records · Page 3Linked to original sources
PubMed1984

Comparative activity of ceftazidime and four other cephalosporins against gram-negative bacteria and their sensitivity to beta-lactamases.

The in vitro activity of ceftazidime compared with other beta-lactamase stable compounds was assessed against recent Gram-negative isolates. Three hundred forty-three bacterial strains were isolated from patients affected with UTI, identified by standard bacteriological methods and investigated for their production of beta-lactamases by the Nitrocefin test. MICs and MBCs (minimum inhibitory concentrations and minimum bactericidal concentration) of ceftazidime, cefamandole, cefoxitin, cefotaxime and cefuroxime were determined by a miniaturized dilution broth method against all beta-lactamase producing bacteria (129 out of 343). Sensitivity of the antibiotics to beta-lactamases isolated and semipurified by ultrasonic disruption and high-speed centrifugation was assessed by a spectrophotometric method. The in vitro antibacterial activity of each antibiotic was correlated to its sensitivity to isolated beta-lactamases. Ceftazidime showed lower MIC and MBC values and lower MBC/MIC ratios than the other compounds against all the bacteria including Pseudomonas spp. In addition, ceftazidime was not hydrolyzed significantly by any isolated beta-lactamases.

Ceftazidime↗
PubMed1983

[Sensitivity of 5 beta-lactam antibiotics to beta-lactamase isolated from E. coli and its respective transconjugates].

54 beta-lactamase producing E. coli were tested to observe their eventual capacity to transfer beta-lactamase production by conjugation to a receiving E. coli K12 C600 Na-. About 16% (9/54) of these strains transferred beta-lactamase producing capacity. MICs of five beta-lactam antibiotics (Ampicillin, Cephaloridine, Cephalexine, Cefuroxime, Cefotaxime) were performed against E. coli donors and E. coli K12 C600 transconjugates. It was observed a remarkable increase only of Ampicillin MICs against all transconjugates++. Beta-lactamases produced by donors and transconjugants were isolated and purified by sonication and high speed centrifugation. Sensitivity of the six antibiotics to these purified beta-lactamases was assessed by a spectrophotometric method that utilizes the velocity of cytochrome c reduction. beta-lactamases produced by transconjugants have identical substrate profile that beta-lactamases produced by donors.

Ampicillin↗
PubMedDate not supplied

Radiologic screening for von Hippel-Lindau disease: the role of Gd-DTPA enhanced MR imaging of the CNS.

Thirty-seven members of a family with von Hippel-Lindau disease (VHL) were prospectively screen for CNS hemangioblastomas; 10 family members were previously known to have VHL. Radiographic studies included noncontrast magnetic resonance (MR) imaging of the head (all patients) and spine (34 patients) and contrast-enhanced CT (CCT) of the head (all adult patients). Eleven patients had Gd-DTPA enhanced MR (CMR) of the head and 10 patients had CMR of the spine. Sixteen patients had radiographic evidence of CNS hemangioblastomas and all but six patients were symptomatic. Using comparable studies, CMR of the head demonstrated more lesions than the other modalities (31, 22, and 19 for CMR, MR, and CCT, respectively). Furthermore, CMR better separated tumor from edema, as well as cystic from solid components. Contrast enhanced MR was superior to noncontrast MR of the spine in lesion detection (31 vs. 4; p less than 0.001). Noncontrast MR was particularly limited in four patients with syringomyelia. We conclude that postcontrast MR of the head and spine is the best currently available means of detecting hemangioblastomas associated with VHL.

Adolescent↗