MR Measures of Small Bowel Wall T2 Are Associated With Increased Permeability.

BACKGROUND: Increased small bowel permeability leads to bacterial translocation, associated with significant morbidity and mortality. Biomarkers are needed to evaluate these changes in vivo, stratify an individual's risk, and evaluate the efficacy of interventions. MRI is an established biomarker of small bowel inflammation. PURPOSE: To characterize changes in the small bowel with quantitative MRI measures associated with increased permeability induced by indomethacin. STUDY TYPE: Prospective single-center, double-blind, two-way crossover provocation study. SUBJECTS: A provocation cohort (22 healthy volunteers) and intrasubject reproducibility cohort (8 healthy volunteers). FIELD STRENGTH/SEQUENCE: 2D balanced turbo field echo sequences to measure small bowel wall thickness, T2 , and motility acquired at 3T. ASSESSMENT: Participants were randomized to receive indomethacin or placebo prior to assessment. After a minimum 2-week washout, measures were repeated with the alternative allocation. MR measures (wall thickness, T2 , motility) at each study visit were compared to the reference standard 2-hour lactulose/mannitol urinary excretion ratio (LMR) test performed by a lab technician. All analyses were performed blind. STATISTICAL TESTS: Normality was tested (Shapiro-Wilk's test). Paired testing (Student's t-test or Wilcoxon) determined the significance of paired differences with indomethacin provocation. Pearson's correlation coefficient compared significant measures with indomethacin provocation to LMR. Intrasubject (intraclass correlation) and interrater variability (Bland-Altman) were assessed. RESULTS: Indomethacin provocation induced a significant increase in LMR compared to placebo (P < 0.05) and a significant increase in small bowel T2 (0.12 seconds compared to placebo 0.07 seconds, P < 0.05). Small bowel wall thickness (P = 0.17) and motility (P = 0.149) showed no significant change. T2 and LMR were positively correlated (r = 0.68, P < 0.05). T2 measurements were robust to interobserver (intraclass correlation 0.89) and intrasubject variability (Bland-Altman bias of 0.005 seconds, 95% confidence interval [CI] -0.04 to +0.05 seconds, and 0.0006 seconds, 95% CI -0.05 to +0.06 seconds). DATA CONCLUSION: MR measures of small bowel wall T2 were significantly increased following indomethacin provocation and correlated with 2-hour LMR test results. LEVEL OF EVIDENCE: 1 TECHNICAL EFFICACY STAGE: 2.

Test-retest assessment of non-contrast MRI sequences to characterise and quantify the small bowel wall in healthy participants.

OBJECTIVE: Quantitative Magnetic Resonance Imaging sequences have been investigated as objective imaging biomarkers of fibrosis and inflammation in Crohn's disease. AIM: To determine the repeatability and inter- and intra-observer agreement of these measures in the prepared small bowel wall. METHODS: Ten healthy participants were scanned at 3 T on 2 separate occasions using T1 and T2 relaxometry, IVIM-DWI and MT sequences. Test-retest repeatability was assessed using the coefficient of variation (CoV) and intra-class correlation coefficients (ICCs) were used to evaluate the intra- and inter-observer agreement RESULTS: Test-retest repeatability in the bowel wall was excellent for apparent diffusion coefficient (ADC), magnetisation transfer ratio (MTR), T1, and diffusion coefficient D (CoV 5%, 7%, 8%, and 10%, respectively), good for perfusion fraction (PF) (CoV 20%) and acceptable for T2 (CoV 21%). Inter-observer agreement was good for the T2, D and ADC (ICC = 0.89, 0.86, 0.76, respectively) and moderate for T1 (ICC = 0.55). Intra-observer agreement was similar to inter-observer agreement. DISCUSSION: This study showed variable results between the different parameters measured. Test-retest repeatability was at least acceptable for all parameters except pseudo-diffusion coefficient D*. Good inter- and intra-observer agreement was obtained for T2, ADC and D, with these parameters performing best in this technical validation study.

Determination of the diversity of astroviruses in feces from cats in Florida.

Astroviruses are small, nonenveloped RNA viruses that have been linked to numerous diseases in a variety of species, including enteric disease in humans and cheetahs. Species Mamastrovirus 2, previously known as feline astrovirus, has been isolated from the feces of domestic cats and cheetahs. A total of 122 cat fecal samples from Alachua County, FL Animal Services and the Veterinary Community Outreach Program at the University of Florida were analyzed, and 35 contained astroviral RNA that was amplified and identified using consensus RT-PCR and sequence analysis. Using phylogenetic analysis, 19 of the astroviral sequences were identified as Mamastrovirus 2, making it the most prevalent astrovirus in this population. Three samples were identified as an astrovirus similar to viruses previously identified in foxes in The Netherlands and a cat in California, and one was similar to a bat astrovirus. One astroviral sequence was identified as an Avastrovirus. Although a causative relationship between mamastroviruses and enteric disease in cats has yet to be established, it is clear that mamastroviruses are prevalent, and an understanding of prevalence of astroviral types may help direct future test development.

Development and validation of a probe hybridization reverse-transcription quantitative PCR for detection of mamastrovirus 2 in domestic cats.

Astroviruses are viral pathogens that have been associated with enteric and neurologic disease in a variety of species. The domestic cat is a prominent host, with reports of astroviral infection being both highly prevalent and widely distributed in the feline population. Despite the potential for inducing significant disease, especially within shelter environments, there is currently only one reliable method of detection: standard reverse-transcription PCR using pan-astrovirus degenerate primers (consensus RT-PCR) with product sequencing. Unfortunately, this process is relatively slow and costly. Quantitative real-time PCR (qPCR) represents an efficient, economical alternative, with the added benefit of viral load quantification. We developed a RT-qPCR assay using probe hybridization technique to detect conserved regions of mamastrovirus 2 extracted from fecal samples of domestic cats. Known positive and negative samples were tested, and results were compared with gold standard consensus RT-PCR and sequencing. A standard curve was employed to determine limits of detection. In order to assess analytic specificity, we tested several additional samples that had been collected from non-felid species and were known to contain non-target astroviruses. Discrepant results between consensus RT-PCR and RT-qPCR testing were further analyzed with a validation RT-PCR assay, using mamastrovirus 2-specific primers. Our probe hybridization RT-qPCR assay is reliable and effective for the detection of mamastrovirus 2. This assay will allow rapid, affordable detection and facilitate further research on astroviral infection within domestic cats.

Smoke-derived taint in wine: effect of postharvest smoke exposure of grapes on the chemical composition and sensory characteristics of wine.

Although smoke exposure has been associated with the development of smoke taint in grapes and subsequently in wine, to date there have been no studies that have demonstrated a direct link. In this study, postharvest smoke exposure of grapes was utilized to demonstrate that smoke significantly influences the chemical composition and sensory characteristics of wine and causes an apparent 'smoke taint'. Verdelho grapes were exposed to straw-derived smoke for 1 h and then fermented according to two different winemaking treatments. Control wines were made by fermenting unsmoked grapes. Sensory studies established a perceivable difference between smoked and unsmoked wines; smoked wines were described as exhibiting 'smoky', 'dirty', 'earthy', 'burnt' and 'smoked meat' characteristics. Quantitative analysis, by means of gas chromatography-mass spectrometry, identified guaiacol, 4-methylguaiacol, 4-ethylguaiacol, 4-ethylphenol, eugenol, and furfural in each of the wines made from smoked grapes. However, these compounds were not detected in the unsmoked wines, and their origin is therefore attributed to the application of smoke. Increased ethanol concentrations and browning were also observed in wines made from grapes exposed to smoke.

Evaluation of Blue Crab, Callinectes sapidus, Megalopal Settlement and Condition during the Deepwater Horizon Oil Spill.

The Blue Crab, Callinectes sapidus, is a commercially, culturally, and ecologically significant species in the Gulf of Mexico (GOM), whose offshore stages were likely impacted by the Deepwater Horizon oil spill (DWH). To test for DWH effects and to better understand the planktonic ecology of this species, we monitored Callinectes spp. megalopal settlement and condition at sites within and outside of the spill extent during and one year after the DWH. We tested for DWH effects by comparing 2010 settlement against baseline data available for two sites, and by testing for differences in settlement and condition inside and outside of the spill extent. We also developed time series models to better understand natural drivers of daily settlement variation (seasonal and lunar trends, hydrodynamics, wind) during 2010 and 2011. Overall, we found that neither megalopal settlement nor body weight were significantly reduced at oiled sites, but that high unexplained variation and low statistical power made detection of even large effects unlikely. Time series models revealed remarkably consistent and relatively strong seasonal and lunar trends within sites (explaining on average 28% and 9% of variation, respectively), while wind and hydrodynamic effects were weak (1-5% variation explained) and variable among sites. This study provides insights into DWH impacts as well as the natural drivers of Callinectes spp. megalopal settlement across the northern GOM.