Search results for " processing"
showing 10 items of 7549 documents
Causal relationships in the variability of cardiovascular system evoked by orthostatic stress by transfer entropy.
2015
The coupling between cardiac and vascular systems in healthy volunteers, elicited by the head-up tilt test is estimated by means of transfer entropy with non-uniform embedding. The method applied to beat-to-beat recordings with heart periods and systolic blood pressure, supports the commonly accepted model, that baroreflex is the key factor in maintaining homeostatic blood distribution after tilting. However the method applied to changes of heart periods and changes of blood pressure, display switches in the driving system, from vascular in the early tilt, to cardiac just after the early tilt and back to vascular in the late tilt.
Repetitive TMS over the left dorsolateral prefrontal cortex modulates the error positivity: An ERP study
2019
Abstract Error processing is a critical step towards an efficient adaptation of our behavior to achieve a goal. Little research has been devoted to investigate the contribution of the dorsolateral prefrontal cortex (DLPFC) in supporting error processing. In this study, the causal relationship of the DLPFC in error commission was examined by means of a repetitive transcranial magnetic stimulation protocol (rTMS). Specifically, the effects of an inhibitory protocol were assessed by examining the electroencephalographic signal recorded during the execution of a Go/No-Go task. To this aim, a group of 15 healthy young participants performed a three-session study. At each session, either the righ…
Modulation of [18F]fluorodopa (FDOPA) kinetics in the brain of healthy volunteers after acute haloperidol challenge.
2006
In animal studies, acute antipsychotic treatment was shown to enhance striatal DOPA-decarboxylase (DDC) activity. However, this phenomenon has not been demonstrated in humans by positron emission tomography (PET). Therefore, we investigated acute haloperidol effects on DDC activity in humans using [18F]fluorodopa (FDOPA) PET. Nine healthy volunteers were scanned with FDOPA in drug-free baseline conditions and after 3 days of haloperidol treatment (5 mg/day). A continuous performance test (CPT) was administered in both conditions. The net blood-brain clearance of FDOPA (K(in)app) in striatum, mesencephalon, and medial prefrontal cortex was calculated by volume-of-interest analysis. The macro…
Capsule Endoscopy versus Push Enteroscopy in Patients with Occult Gastrointestinal Bleeding
2003
Background Wireless capsule endoscopy is a new method enabling non-invasive diagnostic endoscopy of the entire small intestine. In this study we prospectively examined the diagnostic precision of capsule endoscopy compared with push enteroscopy in patients with occult gastrointestinal bleeding. Methods Between July 2001 and October 2002 we examined 48 patients with suspected disorders of the small intestine using capsule endoscopy. 33 patients with obscure bleeding (19 men, 14 women, mean age 58 +/- 23 years) were prospectively examined using capsule endoscopy and push enteroscopy. Results On average, the patients had been suffering from chronic gastrointestinal bleeding for 30 +/- 36 (1-12…
Age-related dermal collagen changes during development, maturation and ageing - a morphometric and comparative study.
2014
The tissue organisation of dermal collagen is gaining importance as a contributing factor both in development and ageing, as well as in skin maturation processes. In this work we aim to study different representative parameters of this structural organisation in 45 human skin samples of assorted ages, by means of image analysis. The variation of these parameters on the basis of age was assessed using several regression models (linear, quadratic and cubic). The area occupied by collagen was significantly reduced as a function of age in the papillary dermis (R(2) = 0.437, P < 0.0001), as well as the thickness of the collagen bundles (R(2) = 0.461, P < 0.0001), following statistical models of …
Identification of unknown dead bodies by X-ray image comparison of the skull using the X-ray simulation program FoXSIS.
2001
The aim of the study was to improve the objectivity of X-ray image comparison for the identification of unknown dead individuals. CT-data were collected for 30 macerated skulls. An already presented computer program which uses CT data to establish virtual X-ray images was used to obtain X-rays with different beam angulations simulating rotation, dorsal flexion, and ventral flexion. Specific parameters were measured on the simulated images. The frontal sinus reveals the highest variability not only between the individual skulls but also within an individual skull in different positions. The most consistent parameters with respect to different positions were the skull breadth, the biorbital b…
Role of high-resolution ultrasonography without and with real-time spatial compound imaging in evaluating the injured posterior cruciate ligament: pr…
2009
This study sought to compare high-resolution ultrasonography (HRUS) without and with compound imaging in evaluating the injured posterior cruciate ligament (PCL). Thirteen patients with a magnetic resonance imaging (MRI) diagnosis of PCL lesions (ten acute and three chronic) and 20 healthy controls underwent conventional and compound HRUS performed by the same radiologist who was blinded to the subjects' case-control status. The PCL was scanned in a longitudinal direction in all cases. HRUS images were assessed for PCL thickness by two other radiologists blinded to the number and type of PCL injury. PCLs were classified as normal or injured, and the latter as having acute or chronic injurie…
Intrahepatic biliary anatomy derived from right graft adult live donor liver transplantation
2008
Abstract Objective The successful management of the bile duct in right graft adult live donor liver transplantation requires knowledge of both its central (hilar) and distal (sectorial) anatomy. The purpose of this study was to provide a systematic classification of its branching patterns to enhance clinical decision-making. Patients and Methods We analyzed three-dimensional computed tomography (3-D CT) imaging reconstructions of 139 potential live liver donors evaluated at our institution between January 2003 and June 2007. Results Fifty-four (n = 54 or 38.8%) donor candidates had a normal (classic) hilar and sectorial right bile duct anatomy (type I). Seventy-eight (n = 78 or 56.1%) cases…
Effect of Kernels Used for the Reconstruction of MDCT Datasets on the Semi-Automated Segmentation and Volumetry of Liver Lesions
2014
Purpose: To evaluate the effect of different reconstruction kernels on the semi-automated segmentation of liver lesions in MDCT. Materials and Methods: A total 62 liver lesions were measured by three independent radiologists with the semi-automated segmentation software Oncology-Prototype (Fraunhofer MEVIS, Siemens Healthcare, Germany) using MDCT datasets (3-mm slice thickness, 2-mm increment) reconstructed with standard, soft and detailed kernels (Philips B, A and D). To ensure objective measurements, only lesions with satisfactory initial segmentation were included, and manual correction was not used. The effective diameter and volume were recorded for each lesion. Segmentation in the sof…
CD3+ lymphocytosis in the peri-implant membrane of 222 loosened joint endoprostheses depends on the tribological pairing.
2017
Background and purpose — The most frequent cause of arthroplasty failure is aseptic loosening—often induced by particles. Abrasion material triggers inflammatory reactions with lymphocytic infiltration and the formation of synovial-like interface membranes (SLIM) in the bone–implant interface. We analyzed CD3 quantities in SLIM depending on articulating materials and possible influences of proven material allergies on CD3 quantities. Patients and methods — 222 SLIM probes were obtained from revision surgeries of loosened hip and knee arthroplasties. SLIM cases were categorized according to the SLIM-consensus classification and to the particle algorithm. The CD3 quantities were analyzed immu…