I. Rodríguez

Antimicrobial Activity of Fosfomycin-Tobramycin Combination against Pseudomonas aeruginosa Isolates Assessed by Time-Kill Assays and Mutant Prevention Concentrations

ABSTRACT The antibacterial activity of fosfomycin-tobramycin combination was studied by time-kill assay in eight Pseudomonas aeruginosa clinical isolates belonging to the fosfomycin wild-type population (MIC = 64 μg/ml) but with different tobramycin susceptibilities (MIC range, 1 to 64 μg/ml). The mutant prevention concentration (MPC) and mutant selection window (MSW) were determined in five of these strains (tobramycin MIC range, 1 to 64 μg/ml) in aerobic and anaerobic conditions simulating environments that are present in biofilm-mediated infections. Fosfomycin-tobramycin was synergistic and bactericidal for the isolates with mutations in the mexZ repressor gene, with a tobramycin MIC of 4 μg/ml. This effect was not observed in strains displaying tobramycin MICs of 1 to 2 μg/ml due to the strong bactericidal effect of tobramycin alone. Fosfomycin presented higher MPC values (range, 2,048 to >2,048 μg/ml) in aerobic and anaerobic conditions than did tobramycin (range, 16 to 256 μg/ml). Interestingly, the association rendered narrow or even null MSWs in the two conditions. However, for isolates with high-level tobramycin resistance that harbored aminoglycoside nucleotidyltransferases, time-kill assays showed no synergy, with wide MSWs in the two environments. glpT gene mutations responsible for fosfomycin resistance in P. aeruginosa were determined in fosfomycin-susceptible wild-type strains and mutant derivatives recovered from MPC studies. All mutant derivatives had changes in the GlpT amino acid sequence, which resulted in a truncated permease responsible for fosfomycin resistance. These results suggest that fosfomycin-tobramycin can be an alternative for infections due to P. aeruginosa since it has demonstrated synergistic and bactericidal activity in susceptible isolates and those with low-level tobramycin resistance. It also prevents the emergence of resistant mutants in either aerobic or anaerobic environments.

Remote sensing of water clouds temperature with an infrared camera on board the International Space Station in the frame of Japan Experiment Module-Extreme Universe Space Observatory mission

Abstract The Extreme Universe Space Observatory (EUSO) is an astronomical telescope that will be hosted by the Japan Experiment Module (JEM) on the International Space Station. The telescope will determine ultrahigh-energy cosmic ray properties by measuring the UV fluorescence light generated in the interaction between the cosmic rays and the atmosphere. Therefore, cloud information is crucial for a proper interpretation of the data. To obtain the cloud top height, an infrared (IR) camera is being designed. The design is constrained by JEM-EUSO requirements, which have led to a bi-spectral camera option (10.8- and 12-μm bands). The bi-spectral design has allowed us to develop a split-window algorithm to correct the atmospheric effects and retrieve the cloud temperature from the brightness temperatures (BTs) in the bands aforementioned. The algorithm has been validated in synthetic scenarios at pixel level. The results show that the algorithm is able to retrieve the temperature with accuracy much better than the requirement of 3K. It has also been tested in two-dimensional scenarios by applying it to moderate resolution imaging spectroradiometer (MODIS) images of BTs in bands 31 similar to those of the IR camera. The retrieved temperatures are in a very good agreement with the temperatures given by MODIS.

Remote sensing of water clouds temperature with an IR camera on board the ISS in the frame of JEM-EUSO Mission

The Extreme Universe Space Observatory (EUSO) is an astronomical telescope that will be hosted by the Japan Experiment Module (JEM) on the International Space Station (ISS). The telescope will determine Ultra High Energy Cosmic Rays properties by measuring the UV fluorescence light emitted by the particles generated in the interaction between the cosmic rays and the atmosphere. Therefore, cloud information is crucial for a proper interpretation of the data. To obtain the cloud top height an IR camera is being designed. The design is constrained by JEM-EUSO requirements which are mainly the instrument weight, power and data rate. These requirements have led to a bi-spectral camera option with 1 μm-wide bands centered at 10.8 and 12 μm. The bi-spectral design has allowed us to develop a Split Window Algorithm to correct the atmospheric effects and retrieve the cloud temperature from the brightness temperatures in the bands aforementioned. The algorithm has been checked in synthetic scenarios at pixel level. The simulations consider clouds at different levels with diverse atmospheric conditions. The results show that the algorithm is able to retrieve the temperature with accuracy much better than the required one by the JEM-EUSO mission of 3K. It has also been tested in 2D real scenarios (MODIS images). The algorithm has been applied to MODIS brightness temperatures in bands 31 and 32 which are similar to those of the IR camera. The temperatures retrieved by the algorithm are in a very good agreement with the cloud top temperatures given by MODIS.

Cerebral Microbleeds in Advanced Dementia: Clinical and Pathological Correlates

Objective: We conducted a longitudinal study to explore the clinical and pathological correlates of cerebral microbleeds (CMBs) in institutionalized patients with dementia. Methods: Clinical and magnetic resonance imaging (MRI) data were extracted from 182 nursing home patients (mean age [standard deviation]: 81.3 [6.9], 78.0% female, and 83.4% moderate to severe dementia), which were divided according to the CMBs number and location. One-year follow-up data were obtained from 153 patients, and postmortem pathological diagnosis was available in 40 patients. Results: Cerebral microbleeds were observed in 42.9% of patients and were associated with MRI ischemic lesions (P < .0005). In the adjusted analysis, lobar CMB predicted worsening of parkinsonism (standardized β: 0.43) and gait (standardized β: 0.24). A pathological diagnosis of Alzheimer’s disease was less frequent in the brains of patients with lobar and deep CMB (33.3% vs 85.3%; P < .05). Conclusion: Cerebral microbleeds were linked to cerebrovascular disease and predicted motor deterioration in institutionalized people with advanced dementia.