Extended apical enlargement with hand files versus rotary NiTi files. Part II.

OBJECTIVE: The objective of this study was to compare 2 preparation techniques performed under simulated clinical conditions with extended apical enlargement following determination of the optimal apical preparation size (APS). STUDY DESIGN: After preflaring 240 root canals, APS was evaluated as outlined in Part I. The apical portion was shaped to APS either with rotary NiTi Lightspeed instruments (LS) or NiTi hand instruments (HA) using the balanced force technique in a phantom head. After sectioning the apical area at 3 levels, every cross section was analyzed microscopically for circumferential removal of canal wall dentine. Loss of working length, instrument separation, and perforation were additionally recorded. RESULTS: In 70% (LS) and 69% (HA) of the root canals, 2 of 3 levels demonstrated that the root canal dentin was cut circumferentially. Neither loss of working length nor perforation occurred in both groups. Four LS instruments separated. CONCLUSIONS: APS frequently results in a nearly complete apical preparation regardless of the preparation techniques. In a few cases apical enlargement to APS does not achieve complete cutting of the canal walls. There was a rather slight risk of serious procedural errors.     

Study on the Tongue and Groove Effect of the Elekta Multileaf Collimator Using Monte Carlo Simulation and Film Dosimetry

BACKGROUND: Nowadays, multileaf collimation of the treatment fields from medical linear accelerators is a common option. Due to the design of the leaf sides, the tongue and groove effect occurs for certain multileaf collimator applications such as the abutment of fields where the beam edges are defined by the sides of the leaves. MATERIAL AND METHODS: In this study, the tongue and groove effect was measured for two pairs of irregular multileaf collimator fields that were matched along leaf sides in two steps. Measurements were made at 10 cm depth in a polystyrene phantom using Kodak EDR2 films for a photon beam energy of 6 MV on an Elekta Sli-plus accelerator. To verify the measurements, full Monte Carlo simulations were done. In the simulations, the design of the leaf sides was taken into account and one component module of BEAM code was modified to correctly simulate the Elekta multileaf collimator. RESULTS AND CONCLUSION: The results of measurements and simulations are in good agreement and within the tolerance of film dosimetry.     

Problems and needs for improving primary care of osteoarthritis patients: the views of patients, general practitioners and practice nurses

Background  

Osteoarthritis (OA) is highly prevalent and has substantial impact on quality of life as well as on healthcare costs. The general practitioner (GP) often is the first care provider for patients with this chronic disease. The aim of this study was to identify health care needs of patients with OA and to reveal possible obstacles for improvements in primary care management of OA patients.     

Ärztliche Fehleroffenbarung – Strafrechtliche Strategien für postinvasive Arzt-Patientengespräche

Ohne Zusammenfassung     

Streitwertkatalog für die Sozialgerichtsbarkeit Streitwertkatalog 2007

Ohne Zusammenfassung     

Voraussetzungen der ICD-Implantation Ist eine elektrophysiologische Untersuchung heute noch unumg?nglich?

Elektrophysiologische Untersuchungen (EPU) und programmierte Ventrikelstimulationen (PVS) werden vor der Implantation eines Defibrillators (ICD) empfohlen, wenn Patienten ohne nachweisbare strukturelle Herzerkrankung oder mit hypertrophischer obstruktiver Kardiomyopathie (HOCM) einen Herzstillstand überlebt haben, weil die Prävalenz von prinzipiell kurierbaren Rhythmusstörungen wie idiopathischen ventrikulären Tachykardien (VT), bei diesen Patienten hoch ist. Gleiches gilt für Patienten nach überlebtem Herzstillstand mit einer kurzen PQ-Zeit oder einer Deltawelle. Patienten mit Tachykardien, bei denen die Diagnose VT unsicher ist, sollten ebenfalls einer EPU unterzogen werden. Wenn sich Patienten mit nicht anhaltenden Tachykardien oder Synkopen vorstellen, sind eine EPU und PVS zur Risikostratifizierung indiziert. Bei den übrigen Patienten mit eingeschränkter linksventrikulärer Pumpfunktion nach überlebtem Herzstillstand oder instabiler VT, die Kandidaten für eine ICD-Implantation sind, haben die EPU und PVS möglicherweise nur einen geringen Nutzen.     

Pyruvate-modified perfadex improves lung function after long-term hypothermic storage.

BACKGROUND: Lungs harvested for transplantation are stored while inflated with oxygen, which can serve to support oxidative metabolism. However, strategies aimed at increasing graft metabolism during storage have received little attention. In this study, we added pyruvate to the preservation solution Perfadex and measured the effects on oxidative metabolism and reperfusion lung function. METHODS: Rat lungs were stored for 6 and 24 hours in low-potassium dextran solution at 10 degrees C containing either 5 mmol/liter uniformly carbon-13 (U-(13)C) labeled glucose (Perfadex), 32 mmol/liter 3-(13)C pyruvate (pyruvate), or both (combined). Oxidation of exogenous substrates was measured as the incorporation of (13)C into tricarboxylic acid cycle intermediates by magnetic resonance spectroscopy. Additional groups of lungs with each substrate modification were preserved for 6 or 24 hours and then reperfused. RESULTS: Enrichment of tricarboxylic acid cycle intermediates was low in the Perfadex group (9% at 6 hours and 32% at 24 hours of storage, respectively). In contrast, enrichment was significantly increased in both the pyruvate group (50% and 59%, respectively) and combined group (39% and 54%, respectively) compared with the Perfadex group (p<0.01). Graft function was excellent after 6-hour storage in all groups. All lungs stored for 24 hours exhibited inferior lung function, but oxygenation, pulmonary artery pressures, and airway pressures in the combined group were significantly improved compared with the Perfadex group (p<0.05). CONCLUSIONS: Preservation solution substrate composition influences graft metabolism during storage. The addition of pyruvate to Perfadex increases metabolism during storage and improves reperfusion lung function.     

Three-dimensional magnetic resonance myocardial motion tracking from a single image plane.

Three-dimensional imaging for the quantification of myocardial motion is a key step in the evaluation of cardiac disease. A tagged magnetic resonance imaging method that automatically tracks myocardial displacement in three dimensions is presented. Unlike other techniques, this method tracks both in-plane and through-plane motion from a single image plane without affecting the duration of image acquisition. A small z-encoding gradient is subsequently added to the refocusing lobe of the slice-selection gradient pulse in a slice following CSPAMM acquisition. An opposite polarity z-encoding gradient is added to the orthogonal tag direction. The additional z-gradients encode the instantaneous through plane position of the slice. The vertical and horizontal tags are used to resolve in-plane motion, while the added z-gradients is used to resolve through-plane motion. Postprocessing automatically decodes the acquired data and tracks the three-dimensional displacement of every material point within the image plane for each cine frame. Experiments include both a phantom and in vivo human validation. These studies demonstrate that the simultaneous extraction of both in-plane and through-plane displacements and pathlines from tagged images is achievable. This capability should open up new avenues for the automatic quantification of cardiac motion and strain for scientific and clinical purposes.