Time esophageal pH < 4 overestimates the prevalence of pathologic esophageal reflux in subjects with gastroesophageal reflux disease treated with proton pump inhibitors

<p>Abstract</p> <p>Background</p> <p>A Stanford University study reported that in asymptomatic GERD patients who were being treated with a proton pump inhibitor (PPI), 50% had pathologic esophageal acid exposure.</p> <p>Aim</p> <p>We considered the possibility that the high prevalence of pathologic esophageal reflux might simply have resulted from calculating acidity as time pH < 4.</p> <p>Methods</p> <p>We calculated integrated acidity and time pH < 4 from the 49 recordings of 24-hour gastric and esophageal pH from the Stanford study as well as from another study of 57 GERD subjects, 26 of whom were treated for 8 days with 20 mg omeprazole or 20 mg rabeprazole in a 2-way crossover fashion.</p> <p>Results</p> <p>The prevalence of pathologic 24-hour esophageal reflux in both studies was significantly higher when measured as time pH < 4 than when measured as integrated acidity. This difference was entirely attributable to a difference between the two measures during the nocturnal period. Nocturnal gastric acid breakthrough was not a useful predictor of pathologic nocturnal esophageal reflux.</p> <p>Conclusion</p> <p>In GERD subjects treated with a PPI, measuring time esophageal pH < 4 will significantly overestimate the prevalence of pathologic esophageal acid exposure over 24 hours and during the nocturnal period.</p

Minor and Unsystematic Cortical Topographic Changes of Attention Correlates between Modalities

In this study we analyzed the topography of induced cortical oscillations in 20 healthy individuals performing simple attention tasks. We were interested in qualitatively replicating our recent findings on the localization of attention-induced beta bands during a visual task [1], and verifying whether significant topographic changes would follow the change of attention to the auditory modality. We computed corrected latency averaging of each induced frequency bands, and modeled their generators by current density reconstruction with Lp-norm minimization. We quantified topographic similarity between conditions by an analysis of correlations, whereas the inter-modality significant differences in attention correlates were illustrated in each individual case. We replicated the qualitative result of highly idiosyncratic topography of attention-related activity to individuals, manifested both in the beta bands, and previously studied slow potential distributions [2]. Visual inspection of both scalp potentials and distribution of cortical currents showed minor changes in attention-related bands with respect to modality, as compared to the theta and delta bands, known to be major contributors to the sensory-related potentials. Quantitative results agreed with visual inspection, supporting to the conclusion that attention-related activity does not change much between modalities, and whatever individual changes do occur, they are not systematic in cortical localization across subjects. We discuss our results, combined with results from other studies that present individual data, with respect to the function of cortical association areas

The Prevalence of Distal and Proximal Gastroesophageal Reflux in Patients Awaiting Lung Transplantation

OBJECTIVE: To determine the prevalence and proximal extent of gastroesophageal reflux (GERD) in patients awaiting lung transplantation. BACKGROUND: GERD has been postulated to contribute to accelerated graft failure in patients who have had lung transplantations. However, the prevalence of reflux symptoms, esophageal motility abnormalities, and proximal esophageal reflux among patients with end-stage lung disease awaiting lung transplantation are unknown. METHODS: A total of 109 patients with end-stage lung disease awaiting lung transplantation underwent symptomatic assessment, esophageal manometry, and esophageal pH monitoring (using a probe with 2 sensors located 5 and 20 cm above the lower esophageal sphincter). RESULTS: Reflux symptoms were not predictive of the presence of reflux (sensitivity, 67%; specificity, 26%). Esophageal manometry showed a high prevalence of a hypotensive lower esophageal sphincter (55%) and impaired esophageal peristalsis (47%) among patients with reflux. Distal reflux was present in 68% of patients and proximal reflux was present in 37% of patients. CONCLUSIONS: These data show that in patients with end-stage lung disease: 1) symptoms were insensitive and nonspecific for diagnosing reflux; 2) esophageal motility was frequently abnormal; 3) 68% of patients had GERD; 4) in 50% of the patients with GERD, acid refluxed into the proximal esophagus. We conclude that patients with end-stage lung disease should be screened with pH monitoring for GERD

Country of origin labeling and structural change in U.S. imports of Canadian cattle and beef

Mandatory country of origin labeling (COOL) has become a thorny issue in U.S.–Canada bilateral trade relations. We undertake an ex post investigation of the impact of the law on U.S. imports of Canadian beef, feeder, and fed cattle. Using a partial equilibrium framework, we derive U.S. import demand equations for Canadian cattle and beef, and employ the Bai and Perron (1998, 2003) procedure for detecting multiple structural breaks with break points being endogenously determined. We find evidence that COOL may have caused significant structural change in U.S. imports of Canadian feeder and fed cattle.Peer Revie

Task-related EEG Power.

<p>Time course of power (converted to z-score with respect to baseline) in one example subject. At left, visual task, right, auditory. From top to bottom, beta2, beta1, alpha2, alpha1, theta and delta.</p

Grand average of root mean global field power (computed at peak of corrected latency averages) converted into SNR, by frequency band (V = visual task; A = auditory task).

<p>Significant increases in power with respect to baseline are indicated by asterisks (p<0.01, paired t-tests).</p

Audio-visual topographic comparisons.

<p>Examples of topographic maps (three-map sets represents first or baseline (I), second (‘task-exclusive’ used for comparisons- II) and third (III) ICA components in each frequency band (indicated at left of each auditory = A visual = V pair; nasion on top of maps). Each of the three line sets is labeled according to each representative subject (“high”, subject that presented the highest inter-modality correlations of attention-related results; “medium”, subject of median correlations; “low”, subject of lowest correlations in the group). Hot versus cold colors indicate opposite polarity of purely spatial patterns (temporal patterns were complex, always with phase differences between components).</p