246 research outputs found
Differences in cerebral response to esophageal acid stimuli and psychological anticipation in GERD subtypes-An fMRI study
No full textBackground: To evaluate whether there are differences in the cerebral response to intraesophageal acid and psychological anticipation stimuli among subtypes of gastroesophageal reflux disease (GERD)
The feasibility of light microscopic measurements of intercellular spaces in squamous epithelium in the lower-esophagus of GERD patients
No full textP>The study aims to determine whether light microscopy can be used to accurately measure the diameters of intercellular spaces between squamous epithelial cells in the lower esophagus, and whether changes in this outcome measure can be used as a diagnostic marker for gastroesophageal reflux disease (GERD). The study has two parts. Part 1 involves 42 asymptomatic controls and 119 patients with typical symptoms of GERD, including 58 with erosive esophagitis (EE), and 61 patients with nonerosive gastroesophageal reflux disease (NERD). All biopsies were taken from the lower esophagus. All samples were observed using an immersion objective, after which diameters were measured by computer-assisted morphometry. Part 2 involves 61 individuals who were randomly selected from part 1, including 19 controls, 13 with NERD and 29 with EE. Diameter measurements using both light microscopy and transmission electron microscopy (TEM) were performed for samples of 61 individuals. Samples from a total of 61 individuals (31 male, 30 female, mean age 44.3 +/- 16.0 years) were observed using both light microscopy and TEM. Both methods showed significant differences between control and disease groups; the outcomes from the two methods had a certain correlation (r = 0.605, P = 0.000). Morphometric analysis of all 161 individuals (83 males, 78 females, mean age 41.4 +/- 15.7) showed mean diameters from light microscopy to be 0.58 +/- 0.16 mu m for controls, 1.07 +/- 0.30 mu m for NERD, and 1.29 +/- 0.20 mu m for EE; differences between control and disease groups were significant (P < 0.05). The optimal cut-off value from receiver operator characteristic analysis was 0.85 mu m. Diagnoses were validated using the combination of symptoms of GERD, endoscopy, and 24 h ambulatory pH monitoring as the gold standard. At the optimal cutoff, sensitivity was 93.3% and specificity was 100%. The diameters of the intercellular spaces in squamous epithelium of lower esophagus from controls and in patients with GERD can be quantitatively measured using light microscopy. Dilated diameters can serve as a sensitive, specific, and objective indicator for diagnosis of GERD.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000286214400002&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Gastroenterology & HepatologySCI(E)PubMed5ARTICLE11-52
An Alternative Algebraic Framework for the Simplification of Coupled Cluster Type Expectation Values
No full textThe Coupled-Cluster (CC) method is one of the most popular and efficient correlation methods in quantum chemistry.
Especially the CCSD(T) approximation, which includes single and double excitations by means of the application of the cluster operator
to a reference determinant and triple excitations via a perturbative treatment, has become a standard tool
in quantum chemical applications. However, the method is restricted to relatively small system sizes due to its unfavourable scaling (N^7, where N is the number of basis functions applied).
For the full treatment of triple excitations the scaling advances to N^8 and every further excitation level increases the exponent by two.
The goal of this work is to reduce the calculation time for closed shell systems at least by a factor growing with the excitation level for arbitrary truncation levels.
This is done by restricting the spatial parts of the spin orbitals and thus treat pairs of spin orbitals on the same footing. The restrictions can be easily constructed
for the CCSD model by spin integration.
The derivation of the restrictions arising in higher excited case will be done employing
the spatial orbital excitation operators E.
In the first part of this work an algorithm is derived that is capable of the derivation of the energy and amplitude equations for arbitrary excitation levels. In the second part
an implementation of this algorithm is presented
Differences in cerebral response to esophageal acid stimuli and psychological anticipation in GERD subtypes - An fMRI study
No full textAbstract Background To evaluate whether there are differences in the cerebral response to intraesophageal acid and psychological anticipation stimuli among subtypes of gastroesophageal reflux disease (GERD). Methods Thirty nine patients with GERD and 11 healthy controls were enrolled in this study after gastroscopy and 24 hr pH monitoring. GERD subjects were divided into four subgroups: RE (reflux esophagitis), NERD+ (non-erosive reflux disease with excessive acid reflux), NERD-SI+ (normal acid exposure and positive symptom index) and NERD-SI+ (normal acid exposure and negative symptom index, but responded to proton pump inhibitor trial). Cerebral responses to intraesophageal acid and psychological anticipation were evaluated with fMRI. Results During intraesophageal acid stimulation, the prefrontal cortex (PFC) region was significantly activated in all subgroups of GERD; the insular cortex (IC) region was also activated in RE, NERD+ and NERD-SI- groups; the anterior cingulated cortex (ACC) region was activated only in RE and NERD-SI- groups. The RE subgroup had the shortest peak time in the PFC region after acid was infused, and presented the greatest change in fMRI signals in the PFC and ACC region (P = 0.008 and P = 0.001, respectively). During psychological anticipation, the PFC was significantly activated in both the control and GERD groups. Activation of the IC region was found in the RE, NERD-SI+ and NERD-SI- subgroups. The ACC was activated only in the NERD-SI+ and NERD-SI- subgroups. In the PFC region, the NERD-SI- subgroup had the shortest onset time (P = 0.008) and peak time (P Conclusions The four subgroups of GERD patients and controls showed distinctly different activation patterns and we therefore conclude GERD patients have different patterns of visceral perception and psychological anticipation. Psychological factors play a more important role in NERD-SI+ and NERD-SI- groups than in RE and NERD+ groups.</p
Severity of GERD and disease progression
No full textThis is a pre-copyedited, author-produced version of an article accepted for publication in Diseases of the Esophagus following peer review. The version of record Fuchs, K. H., DeMeester, T. R., Otte, F., Broderick, R. C., Breithaupt, W., Varga, G. & Musial, F. (2021). Severity of GERD and disease progression. Diseases of the Esophagus, ?(?), ?. is available online at: https://doi.org/10.1093/dote/doab006Background - Many factors may play a role in the severity and progression of gastroesophageal reflux disease (GERD) since pathophysiology is multifactorial. Data regarding the progression of GERD are controversial: some reports of increased esophageal acid exposure (EAE) and mucosal damage were considered as evidence for a stable disease course, while others interprete these findings as disease progression. The aim of this study is to analyze a large patient-population with persisting symptoms indicative of GERD under protonpumpinhibitor-therapy and identify components characterizing disease severity and progression.
Methods - Patients with symptoms indicative of GERD were included in the study in a tertiary referral center (Frankfurt, Germany). All selected patients were under long-term protonpumpinhibitor-therapy with persistant symptoms. All patients underwent investigations to collect data on their physical status, EAE, severity of esophagitis, anatomical changes, and esophageal functional defects as well as their relation to the duration of the disease. Incidence over time was plotted as survival curves and tested with Log-rank tests for the four main disease markers. Multivariate modeling with COX-regression model was used to estimate the general impact of the four main disease markers on the time course of the disease. In order to elucidate possible causal relationships over time, a path analysis (structural equation model) was calculated.
Results - From the database with 1480 data sets, 972 patients were evaluated (542 males, 430 females). The mean age was 50.5 years (range18–89). The mean body mass index was 27.2(19–48). The mean time between the onset of symptoms and the diagnostic investigations was 8.2 years (1–50). A longer disease history for GERD was significantly associated with a higher risk for LES-incompetence. The mean duration from symptom onset to the time of clinical investigation was 9 years for patients with LES-incompetence (n = 563), compared to a mean of 6 years for those with mechanically intact LES (n = 95). A longer period from symptom onset to diagnostics was significantly associated with higher acid exposure. The pathway analysis was significant for the following model: ‘history’ (P P
Conclusion - LES-incompetence, the functional deterioration of the LES, and the anatomical alteration at the esophagogastric junction (Hiatal Hernia) as well as an increased EAE were associated with a long history of suffering from GERD. Path modeling suggests a causal sequence overtime of the main disease-parameters, tentatively allowing for a prediction of the course of the disease
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