832 research outputs found
Double chambered right ventricle with severe calcification of the tricuspid valve in an elderly woman: a case report
<p>Abstract</p> <p>Introduction</p> <p>Double chambered right ventricle is a rare congenital cardiac anomaly in which the right ventricle is divided into two chambers by an anomalous muscle bundle. The diagnosis of this disorder is difficult in adults. Calcification of the tricuspid valve is extremely rare, and very few cases have been reported. Most cases of tricuspid valve calcification had a congenital disorder with high pressure in the right ventricle.</p> <p>Case presentation</p> <p>We report a rare case of a 71-year-old Japanese woman who presented with chest discomfort, and was found to have a double chambered right ventricle with severe calcification of the tricuspid valve. This abnormality was found by echocardiography, and the diagnosis was confirmed by multislice cardiac computerized tomography, cardiac magnetic resonance imaging, and cardiac catheterization. Our patient rejected surgical repair, and medical therapy with carvedilol was effective to reduce her symptoms.</p> <p>Conclusion</p> <p>Calcification of the tricuspid valve is extremely rare, and considered to be due to high pressure in the right ventricle. To the best of our knowledge, there are no other reported cases of this combination of double chambered right ventricle and calcification of the tricuspid valve.</p
Hemispheric Specialization in Dogs for Processing Different Acoustic Stimuli
Considerable experimental evidence shows that functional cerebral asymmetries are widespread in animals. Activity of the right cerebral hemisphere has been associated with responses to novel stimuli and the expression of intense emotions, such as aggression, escape behaviour and fear. The left hemisphere uses learned patterns and responds to familiar stimuli. Although such lateralization has been studied mainly for visual responses, there is evidence in primates that auditory perception is lateralized and that vocal communication depends on differential processing by the hemispheres. The aim of the present work was to investigate whether dogs use different hemispheres to process different acoustic stimuli by presenting them with playbacks of a thunderstorm and their species-typical vocalizations. The results revealed that dogs usually process their species-typical vocalizations using the left hemisphere and the thunderstorm sounds using the right hemisphere. Nevertheless, conspecific vocalizations are not always processed by the left hemisphere, since the right hemisphere is used for processing vocalizations when they elicit intense emotion, including fear. These findings suggest that the specialisation of the left hemisphere for intraspecific communication is more ancient that previously thought, and so is specialisation of the right hemisphere for intense emotions
Non-specific binding of antibodies in immunohistochemistry: fallacies and facts
The current protocols for blocking background staining in immunohistochemistry are based on conflicting reports. Background staining is thought to occur as a result of either non-specific antibody (Ab) binding to endogenous Fc receptors (FcRs) or a combination of ionic and hydrophobic interactions. In this study, cell and tissue samples were processed according to routine protocols either with or without a blocking step (goat serum or BSA). Surprisingly, no Abs in samples processed without a blocking step showed any propensity for non-specific binding leading to background staining, implying that endogenous FcRs do not retain their ability to bind the Fc portion of Abs after standard fixation. Likewise, we did not find any non-specific Ab binding ascribable to either ionic or hydrophobic interactions. We determined that traditionally used protein blocking steps are unnecessary in the immunostaining of routinely fixed cell and tissue samples
Impact of on-site cardiac catheterization on resource utilization and fatal and non-fatal outcomes after acute myocardial infarction
BACKGROUND: Patterns of care for acute myocardial infarction (AMI) strongly depend on the availability of on-site cardiac catheterization facilities. Although the management found at hospitals without on-site catheterization does not lead to increased mortality, little it known about its impact on resource utilization and non-fatal outcomes. METHODS: We identified all patients (n = 35,289) admitted with a first AMI in the province of Quebec between January 1, 1996 and March 31, 1999 using population-based administrative databases. Medical resource utilization and non-fatal and fatal outcomes were compared among patients admitted to hospitals with and without on-site cardiac catheterization facilities. RESULTS: Cardiac catheterization and PCI were more frequently performed among patients admitted to hospitals with catheterization facilities. However, non-invasive procedures were not used more frequently at hospitals without catheterization facilities. To the contrary, echocardiography [odds ratio (OR), 2.04; 95% confidence interval (CI), 1.93–2.16] and multi-gated acquisition imaging (OR, 1.24; 95% CI, 1.17–1.32) were used more frequently at hospitals with catheterization, and exercise treadmill testing (OR, 1.02; 95% CI, 0.91–1.15) and Sestamibi/Thallium imaging (OR, 0.93; 95% CI, 0.88–0.98) were used similarly at hospitals with and without catheterization. Use of anti-ischemic medications and frequency of emergency room and physician visits, were similar at both types of institutions. Readmission rates for AMI-related cardiac complications and mortality were also similar [adjusted hazard ratio, recurrent AMI: 1.02, 95% CI, 0.89–1.16; congestive heart failure: 1.02; 95% CI, 0.90–1.15; unstable angina: 0.93; 95% CI, 0.85–1.02; mortality: 0.99; 95% CI, 0.93–1.05)]. CONCLUSION: Although on-site availability of cardiac catheterization facilities is associated with greater use of invasive cardiac procedures, non-availability of catheterization did not translate into a higher use of non-invasive tests or have an impact on the fatal and non-fatal outcomes available for study in our administrative database
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Demonstration of the event identification capabilities of the NEXT-White detector
In experiments searching for neutrinoless double-beta decay, the possibility of identifying the two emitted electrons is a powerful tool in rejecting background events and therefore improving the overall sensitivity of the experiment. In this paper we present the first measurement of the efficiency of a cut based on the different event signatures of double and single electron tracks, using the data of the NEXT-White detector, the first detector of the NEXT experiment operating underground. Using a 228Th calibration source to produce signal-like and background-like events with energies near 1.6 MeV, a signal efficiency of 71.6 ± 1.5 stat± 0.3 sys% for a background acceptance of 20.6 ± 0.4 stat± 0.3 sys% is found, in good agreement with Monte Carlo simulations. An extrapolation to the energy region of the neutrinoless double beta decay by means of Monte Carlo simulations is also carried out, and the results obtained show an improvement in background rejection over those obtained at lower energies. [Figure not available: see fulltext.
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Radiogenic backgrounds in the NEXT double beta decay experiment
Natural radioactivity represents one of the main backgrounds in the search for neutrinoless double beta decay. Within the NEXT physics program, the radioactivity- induced backgrounds are measured with the NEXT-White detector. Data from 37.9 days of low-background operations at the Laboratorio Subterráneo de Canfranc with xenon depleted in 136Xe are analyzed to derive a total background rate of (0.84±0.02) mHz above 1000 keV. The comparison of data samples with and without the use of the radon abatement system demonstrates that the contribution of airborne-Rn is negligible. A radiogenic background model is built upon the extensive radiopurity screening campaign conducted by the NEXT collaboration. A spectral fit to this model yields the specific contributions of 60Co, 40K, 214Bi and 208Tl to the total background rate, as well as their location in the detector volumes. The results are used to evaluate the impact of the radiogenic backgrounds in the double beta decay analyses, after the application of topological cuts that reduce the total rate to (0.25±0.01) mHz. Based on the best-fit background model, the NEXT-White median sensitivity to the two-neutrino double beta decay is found to be 3.5σ after 1 year of data taking. The background measurement in a Qββ±100 keV energy window validates the best-fit background model also for the neutrinoless double beta decay search with NEXT-100. Only one event is found, while the model expectation is (0.75±0.12) events. [Figure not available: see fulltext.]
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Energy calibration of the NEXT-White detector with 1% resolution near Q ββ of 136Xe
Excellent energy resolution is one of the primary advantages of electroluminescent high-pressure xenon TPCs. These detectors are promising tools in searching for rare physics events, such as neutrinoless double-beta decay (ββ0ν), which require precise energy measurements. Using the NEXT-White detector, developed by the NEXT (Neutrino Experiment with a Xenon TPC) collaboration, we show for the first time that an energy resolution of 1% FWHM can be achieved at 2.6 MeV, establishing the present technology as the one with the best energy resolution of all xenon detectors for ββ0ν searches. [Figure not available: see fulltext.
"Closing-in" phenomenon in Alzheimer's disease and subcortical vascular dementia
BACKGROUND: The 'closing-in' phenomenon is defined as a tendency to close in on a model while copying it. This is one of several constructional apraxia observed in dementia, particularly in Alzheimer's disease (AD). The aim of this study was to investigate the usefulness of it in the differential diagnosis of AD and subcortical vascular dementia (SVD) and to clarify the factors associated with it. METHODS: We operationally defined and classified it into three types, namely overlap, adherent, and near type. We analyzed the incidence of it in patients with AD (n = 98) and SVD (n = 48). RESULTS: AD patients exhibited a significantly higher occurrence of it as compared to SVD patients. Among the different types of it, the overlap and adherent types occurred almost exclusively in AD patients. A discriminant analysis in AD subjects revealed that the scores obtained from the MMSE, CDR, Barthel index, and the Rey-Osterrieth complex figure test were correlated significantly with the occurrence of it. There was no statistical difference between the Q-EEG parameters of patients that exhibited the closing-in phenomenon and those that did not. CONCLUSIONS: This study suggests that the closing-in phenomenon is phase- and AD-specific and might be a useful tool for the differential diagnosis of AD and SVD
Factors Associated with Response to Acetylcholinesterase Inhibition in Dementia:A Cohort Study from a Secondary Mental Health Care Case Register in London
Background: Acetylcholinesterase inhibitors (AChEIs) are widely used to delay cognitive decline in Alzheimer's disease. Observational studies in routine clinical practice have shown cognitive improvement in some groups of patients receiving these agents but longitudinal trajectories before and after AChEI initiation have not previously been considered. Objectives: To compare trajectories of cognitive function before and after AChEI initiation and investigate predictors of these differences. Method: A retrospective longitudinal study was constructed using data from 2460 patients who received AChEIs and who had routine data on cognitive function (Mini-Mental State Examination; MMSE) before and after AChEI initiation. Longitudinal MMSE change was modelled using three-piece linear mixed models with the following segments: 0-12 months prior to AChEI initiation, 0-6 months and 6-36 months after initiation. Results: MMSE decline was reversed (in that the slope was improved by an average 4.2 units per year, 95% CI 3.5-4.8) during the 6-month period following AChEI initiation compared with the slope in the one year period before AChEI initiation. The slope in the period from 6-36 months following AChEI initiation returned to the pre-initiation downward trajectory. The differences in slopes in the 1 year period prior to AChEI initiation and in the 6 months after initiation were smaller among those with higher MMSE scores at the time of AChEI initiation, among those who received a vascular dementia diagnosis at any point, and among those receiving antipsychotic agents. Conclusion: In this naturalistic observational study, changes in cognitive trajectories around AChEI initiation were similar to those reported in randomised controlled trials. The magnitude of the difference in slopes between the 1 year period prior to AChEI initiation and the 6 month period after AChEI initiation was related to level of cognitive function at treatment initiation, vascular comorbidity and antipsychotic use
Mucin granule-associated proteins in human bronchial epithelial cells: the airway goblet cell "granulome"
<p>Abstract</p> <p>Background</p> <p>Excess mucus in the airways leads to obstruction in diseases such as chronic bronchitis, asthma, and cystic fibrosis. Mucins, the highly glycosolated protein components of mucus, are stored in membrane-bound granules housed in the cytoplasm of airway epithelial "goblet" cells until they are secreted into the airway lumen via an exocytotic process. Precise mechanism(s) of mucin secretion, including the specific proteins involved in the process, have yet to be elucidated. Previously, we have shown that the Myristoylated Alanine-Rich C Kinase Substrate (MARCKS) protein regulates mucin secretion by orchestrating translocation of mucin granules from the cytosol to the plasma membrane, where the granules dock, fuse and release their contents into the airway lumen. Associated with MARCKS in this process are chaperone (Heat Shock Protein 70 [HSP70], Cysteine string protein [CSP]) and cytoskeletal (actin, myosin) proteins. However, additional granule-associated proteins that may be involved in secretion have not yet been elucidated.</p> <p>Methods</p> <p>Here, we isolated mucin granules and granule membranes from primary cultures of well differentiated human bronchial epithelial cells utilizing a novel technique of immuno-isolation, based on the presence of the calcium activated chloride channel hCLCA1 (the human ortholog of murine Gob-5) on the granule membranes, and verified via Western blotting and co-immunoprecipitation that MARCKS, HSP70, CSP and hCLCA1 were present on the granule membranes and associated with each other. We then subjected the isolated granules/membranes to liquid chromatography mass spectrometry (LC-MS/MS) to identify other granule associated proteins.</p> <p>Results</p> <p>A number of additional cytoskeletal (e.g. Myosin Vc) and regulatory proteins (e.g. Protein phosphatase 4) associated with the granules and could play a role in secretion were discovered. This is the first description of the airway goblet cell "granulome."</p
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