RESUMEN
Over the past two decades, following the discovery of the important biological roles of carbon monoxide (CO), metal carbonyl complexes have been intensively studied as CO-releasing molecules (CORMs) for therapeutic applications. To improve the properties of "bare" low molecular weight CORMs, attention has been drawn to conjugating CORMs with macromolecular and inorganic scaffolds to produce CO-releasing materials (CORMAs) capable of storing and delivering large payloads of the gasotransmitter. A significant obstacle is to obtain CORMAs that retain the beneficial features of the parent CORMs. In the present work, a crystalline metal-organic framework (MOF) formulated as Mo(CO)3(4,4'-bipyridine)3/2 (Mobpy), with a structure based on Mo(CO)3 metallic nodes and bipyridine linkers, has been prepared in near quantitative yield by a straightforward reflux method, and found to exhibit CO-release properties that mimic those typically observed for molybdenum carbonyl CORMs. Mobpy was characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), FT-IR, FT-Raman and diffuse reflectance (DR) UV-vis spectroscopies, and 13C{1H} cross-polarization (CP) magic-angle spinning (MAS) NMR. The release of CO from Mobpy was studied by the deoxy-myoglobin (deoxy-Mb)/carbonmonoxy-myoglobin (MbCO) UV-vis assay. Mobpy liberates CO upon contact with a physiological buffer in the dark, leading to a maximum released amount of 1.3-1.5 mmol g-1, after 1.5 h at 37 °C, with half-lives of 0.5-1.0 h (time to transfer 0.5 equiv. of CO to Mb). In the solid-state and under open air, Mobpy undergoes complete decarbonylation over a period of 42 days, corresponding to a theoretical CO-release of 7.25 mmol g-1.
RESUMEN
OBJECTIVE: To determine the prevalence of pneumococcus colonization among HIV-infected outpatients aged 0 to 18 years. To determine the resistance to penicillin of the microorganisms observed, to identify their serotypes, and to determine whether there are associations between known risk factors and colonization in this group. MATERIAL AND METHOD: This was an observational and cross-sectional study in which nasopharynx swabs were collected from 112 children on the occasion of their monthly appointments and a questionnaire applied to the mothers. The material collected was processed at the microbiology laboratory of the hospital in accordance with National Committee for Clinical Laboratory Standards (NCCLS) regulations and serotyping was performed at the Centers for Diseases Control and Prevention (CDC). Data were analyzed statistically using the chi-square test and with univariate and multivariate analysis with multiple logistic regression. RESULTS: The prevalence rate of nasopharyngeal colonization by pneumococci was 28.6%, with a 15.6% rate of resistance to penicillin (6.2% intermediate resistance and 9.4% full resistance). The serotypes identified were 6A, 6B, 7C, 9V, 11A, 13, 14, 15A, 16F, 18C, 19B, 19F, 23B, 23F, and 34. In this population there were no associations between pneumococcal colonization and the risk factors studied. CONCLUSIONS: The prevalence of pneumococcal colonization among HIV-infected children at our service was not higher than prevalence rates observed in healthy children and reported in the literature.