Rivaroxaban: a novel oral anticoagulant for the prevention and treatment of several thrombosis-mediated conditions.

The development of rivaroxaban (XARELTO®) is an important new medical advance in the field of oral anticoagulation. Thrombosis-mediated conditions constitute a major burden for patients, healthcare systems, and society. For more than 60 years, the prevention and treatment of these conditions have been dominated by oral vitamin K antagonists (such as warfarin) and the injectable heparins. Thrombosis can lead to several conditions, including deep vein thrombosis, pulmonary embolism, myocardial infarction, stroke, and/or death. Prevention and treatment of thrombosis with an effective, convenient-to-use oral anticoagulant with a favorable safety profile is critical, especially in an aging society in which the risk of thrombosis, and the potential for bleeding complications, is increasing. Rivaroxaban acts to prevent and treat thrombosis by potently inhibiting coagulation Factor Xa in the blood. Factor Xa converts prothrombin to thrombin, which initiates the formation of blood clots by converting fibrinogen to clot-forming fibrin and leads to platelet activation. After a large and novel clinical development program in over 75,000 patients to date, rivaroxaban has received approval for multiple indications in the United States, European Union, and other countries worldwide to prevent and treat several thrombosis-mediated conditions. This review will highlight some of the unique aspects of the rivaroxaban development program.

Comparison study of oxygen-induced MRI-signal changes and pO2 changes in murine tumors.

The purpose of this study was to compare the results from oxygen-induced MR-signal intensity changes with polarographic pO2 measurements in tumors. Balb-c mice with an intramuscular transplanted osteosarcoma were examined. To study the response of tumors to changes in oxygen supply, hyperoxia was induced by breathing pure oxygen for a short period. The examination of each animal started with T2* weighted MRI followed by the pO2 measurements (Eppendorf Histograph). During oxygen inhalation in all tumors, when the hypoxic tumor fraction drops, both areas of significant MR-signal intensity increase and decrease were observed in each animal.

Pulmonary diffusing capacity: assessment with oxygen-enhanced lung MR imaging preliminary findings.

PURPOSE: To determine differences in the signal intensity (SI) time courses at oxygen-enhanced magnetic resonance (MR) lung imaging in healthy volunteers and patients with pulmonary diseases and to correlate these differences with pulmonary diffusing capacity. MATERIALS AND METHODS: Seventeen patients with pulmonary diseases and 11 healthy volunteers underwent oxygen-enhanced MR imaging while they breathed room air and 100% oxygen. A turbo spin-echo sequence with global or section-selective inversion pulses was used. For postprocessing, SI slope maps during the breathing of 100% oxygen were calculated. Mean SI slope and SI change values were compared with the diffusing capacity of the lung for carbon monoxide (DLCO). RESULTS: The SI slopes were significantly different for patients and volunteers (P < or = .05, Mann-Whitney U test). Linear correlations were detected between the DLCO and SI slopes for the section-selective inversion pulse (r(2) = 0.81) and the global inversion pulse (r(2) = 0.74). A lower correlation was associated with the SI change for the section-selective pulse (r(2) = 0.04; global pulse, r(2) = 0.81). Regional differences were seen in the SI slope and SI change maps. These differences correlated with findings on radiographs and computed tomographic scans. CONCLUSION: The SI slope during the breathing of 100% oxygen allows spatially resolved assessment of the pulmonary diffusion capacity.