Global transcriptional response to mammalian temperature provides new insight into Francisella tularensis pathogenesis

<p>Abstract</p> <p>Background</p> <p>After infecting a mammalian host, the facultative intracellular bacterium, <it>Francisella tularensis</it>, encounters an elevated environmental temperature. We hypothesized that this temperature change may regulate genes essential for infection.</p> <p>Results</p> <p>Microarray analysis of <it>F. tularensis </it>LVS shifted from 26°C (environmental) to 37°C (mammalian) showed ~11% of this bacterium's genes were differentially-regulated. Importantly, 40% of the protein-coding genes that were induced at 37°C have been previously implicated in virulence or intracellular growth of <it>Francisella </it>in other studies, associating the bacterial response to this temperature shift with pathogenesis. Forty-four percent of the genes induced at 37°C encode proteins of unknown function, suggesting novel <it>Francisella </it>virulence traits are regulated by mammalian temperature. To explore this possibility, we generated two mutants of loci induced at 37°C [FTL_1581 and FTL_1664 (<it>deoB</it>)]. The FTL_1581 mutant was attenuated in a chicken embryo infection model, which was likely attributable to a defect in survival within macrophages. FTL_1581 encodes a novel hypothetical protein that we suggest naming <it>t</it>emperature-<it>i</it>nduced, <it>v</it>irulence-associated locus <it>A</it>, <it>tivA</it>. Interestingly, the <it>deoB </it>mutant showed diminished entry into mammalian cells compared to wild-type LVS, including primary human macrophages and dendritic cells, the macrophage-like RAW 264.7 line, and non-phagocytic HEK-293 cells. This is the first study identifying a <it>Francisella </it>gene that contributes to uptake into both phagocytic and non-phagocytic host cells.</p> <p>Conclusion</p> <p>Our results provide new insight into mechanisms of <it>Francisella </it>virulence regulation and pathogenesis. <it>F. tularensis </it>LVS undergoes considerable gene expression changes in response to mammalian body temperature. This temperature shift is important for the regulation of genes that are critical for the pathogenesis of <it>Francisella</it>. Importantly, the compilation of temperature-regulated genes also defines a rich collection of novel candidate virulence determinants, including <it>tivA </it>(FTL_1581). An analysis of <it>tivA </it>and <it>deoB </it>(FTL_1664) revealed that these genes contribute to intracellular survival and entry into mammalian cells, respectively.</p

The CARTS study: Chemoradiation therapy for rectal cancer in the distal rectum followed by organ-sparing transanal endoscopic microsurgery

Contains fulltext : 96401.pdf (publisher's version ) (Open Access

EEG Biofeedback as a Treatment for Substance Use Disorders: Review, Rating of Efficacy, and Recommendations for Further Research

Electroencephalographic (EEG) biofeedback has been employed in substance use disorder (SUD) over the last three decades. The SUD is a complex series of disorders with frequent comorbidities and EEG abnormalities of several types. EEG biofeedback has been employed in conjunction with other therapies and may be useful in enhancing certain outcomes of therapy. Based on published clinical studies and employing efficacy criteria adapted by the Association for Applied Psychophysiology and Biofeedback and the International Society for Neurofeedback and Research, alpha theta training—either alone for alcoholism or in combination with beta training for stimulant and mixed substance abuse and combined with residential treatment programs, is probably efficacious. Considerations of further research design taking these factors into account are discussed and descriptions of contemporary research are given

Ligand denticity controls enantiomeric preference in DNA-based asymmetric catalysis

DNA-based catalysis can be used to control the enantioselectivity of copper-catalysed Diels–Alder and Friedel–Crafts reactions to produce either enantiomer of the product by changing the denticity of the ligand coordinated to the Cu(II) ion, even though the DNA adopts a right handed helical conformation only.

Spatial cross-validation is not the right way to evaluate map accuracy

For decades scientists have produced maps of biological, ecological and environmental variables. These studies commonly evaluate the map accuracy through cross-validation with the data used for calibrating the underlying mapping model. Recent studies, however, have argued that cross-validation statistics of most mapping studies are optimistically biased. They attribute these overoptimistic results to a supposed serious methodological flaw in standard cross-validation methods, namely that these methods ignore spatial autocorrelation in the data. They argue that spatial cross-validation should be used instead, and contend that standard cross-validation methods are inherently invalid in a geospatial context because of the autocorrelation present in most spatial data. Here we argue that these studies propagate a widespread misconception of statistical validation of maps. We explain that unbiased estimates of map accuracy indices can be obtained by probability sampling and design-based inference and illustrate this with a numerical experiment on large-scale above-ground biomass mapping. In our experiment, standard cross-validation (i.e., ignoring autocorrelation) led to smaller bias than spatial cross-validation. Standard cross-validation was deficient in case of a strongly clustered dataset that had large differences in sampling density, but less so than spatial cross-validation. We conclude that spatial cross-validation methods have no theoretical underpinning and should not be used for assessing map accuracy, while standard cross-validation is deficient in case of clustered data. Model-free, design-unbiased and valid accuracy assessment is achieved with probability sampling and design-based inference. It is valid without the need to explicitly incorporate or adjust for spatial autocorrelation and perfectly suited for the validation of large scale biological, ecological and environmental maps

Pharmacokinetics, metabolism, and disposition of deferasirox in beta-thalassemic patients with transfusion-dependent iron overload who are at pharmacokinetic steady state.

Deferasirox (ICL670) is a novel once-daily, orally administered iron chelator to treat chronic iron overload in patients with transfusion-dependent anemias. Absorption, distribution, metabolism, and excretion of [14C]deferasirox at pharmacokinetic steady state was investigated in five adult beta-thalassemic patients. Deferasirox (1000 mg) was given orally once daily for 6 days to achieve steady state. On day 7, patients received a single oral 1000-mg dose (approximately 20 mg/kg) of [14C]deferasirox (2.5 MBq). Blood, plasma, feces, and urine samples collected over 7 days were analyzed for radioactivity, deferasirox, its iron complex Fe-[deferasirox]2, and metabolites. Deferasirox was well absorbed. Deferasirox and its iron complex accounted for 87 and 10%, respectively, of the radioactivity in plasma (area under the curve at steady state). Excretion occurred largely in the feces (84% of dose), and 60% of the radioactivity in the feces was identified as deferasirox. Apparently unchanged deferasirox in feces was partly attributable to incomplete intestinal absorption and partly to hepatobiliary elimination of deferasirox (including first-pass elimination) and of its glucuronide. Renal excretion was only 8% of the dose and included mainly the glucuronide M6. Oxidative metabolism by cytochrome 450 enzymes to M1 [5-hydroxy (OH) deferasirox, presumably by CYP1A] and M4 (5'-OH deferasirox, by CYP2D6) was minor (6 and 2% of the dose, respectively). Direct and indirect evidence indicates that the main pathway of deferasirox metabolism is via glucuronidation to metabolites M3 (acyl glucuronide) and M6 (2-O-glucuronide)

Dealing with clustered samples for assessing map accuracy by cross-validation

Mapping of environmental variables often relies on map accuracy assessment through cross-validation with the data used for calibrating the underlying mapping model. When the data points are spatially clustered, conventional cross-validation leads to optimistically biased estimates of map accuracy. Several papers have promoted spatial cross-validation as a means to tackle this over-optimism. Many of these papers blame spatial autocorrelation as the cause of the bias and propagate the widespread misconception that spatial proximity of calibration points to validation points invalidates classical statistical validation of maps. We present and evaluate alternative cross-validation approaches for assessing map accuracy from clustered sample data. The first method uses inverse sampling-intensity weighting to correct for selection bias. Sampling-intensity is estimated by a two-dimensional kernel approach. The two other approaches are model-based methods rooted in geostatistics, where the first assumes homogeneity of residual variance over the study area whilst the second accounts for heteroscedasticity as a function of the sampling intensity. The methods were tested and compared against conventional k-fold cross-validation and blocked spatial cross-validation to estimate map accuracy metrics of above-ground biomass and soil organic carbon stock maps covering western Europe. Results acquired over 100 realizations of five sampling designs ranging from non-clustered to strongly clustered confirmed that inverse sampling-intensity weighting and the heteroscedastic model-based method had smaller bias than conventional and spatial cross-validation for all but the most strongly clustered design. For the strongly clustered design where large portions of the maps were predicted by extrapolation, blocked spatial cross-validation was closest to the reference map accuracy metrics, but still biased. For such cases, extrapolation is best avoided by additional sampling or limitation of the prediction area. Weighted cross-validation is recommended for moderately clustered samples, while conventional random cross-validation suits fairly regularly spread samples

Electronic Monitoring-Based Counseling to Enhance Adherence Among HIV-Infected Patients: A Randomized Controlled Trial

Objective: To investigated the effectiveness of an adherence intervention (AIMS) designed to fit HIV-clinics' routine care procedures. Design: Through block randomization, patients were allocated to the intervention or control group. The study included 2 months baseline measurement, 3 months intervention, and 4 months follow-up. HIV-nurses delivered a minimal intervention ("adherence sustaining") to patients scoring >95% adherence at baseline, and an intensive intervention ("adherence improving") to patients with <95% adherence. Control participants received high-quality usual care. Main Outcome Measures: Electronically monitored adherence and viral load. Results: 133 patients were included (67 control, 66 intervention), 60% had <95% adherence at baseline, and 87% (116/133) completed the trial. Intent-to-treat analyses showed that adherence improved significantly in the complete intervention sample. Subgroup analyses showed that this effect was caused by participants scoring <95% at baseline (mean difference = 15.20%; p <.001). These effects remained stable during follow-up. The number of patients with an undetectable viral load increased in the intervention group compared to the control group (OR = 2.96, p <.05). Treatments effects on viral load were mediated by the improvements in adherence. Conclusions: The AIMS-intervention was effective and can be integrated in routine clinical care for HIV-infected patients. Future research should study its (cost)effectiveness among more heterogeneous samples and in settings with variable levels of standard car

Imaging of striatal dopamine transporters in rat brain with single pinhole SPECT and co-aligned MRI is highly reproducible

A recently developed pinhole high-resolution SPECT system was used to measure striatal to non-specific binding ratios in rats (n = 9), after injection of the dopamine transporter ligand I-123-FP-CIT, and to assess its test/retest reproducibility. For co-alignment purposes, the rat brain was imaged on a 1.5 Tesla clinical MRI scanner using a specially developed surface coil. The SPECT images showed clear striatal uptake. On the MR images, cerebral and extra-cerebral structures could be easily delineated. The mean striatal to non-specific [I-123]FP-CIT binding ratios of the test/retest studies were 1.7 +/- 0.2 and 1.6 +/- 0.2, respectively. The test/retest variability was approximately 9%. We conclude that the assessment of striatal [I-123]FP-CIT binding ratios in rats is highly reproducible. (C) 2003 Elsevier Inc. All rights reserve