Acute myocardial ischemia: MR imaging with Mn-TP

Cardiac-gated magnetic resonance (MR) imaging was performed in rats to determine the effects of manganese ethylenediaminetetraphosphonate (TP). Ten normal rats received Mn-TP in a dose of 50 mumol/kg through a tail-vein injection. Spin-echo MR images were obtained before and every 10 minutes after Mn-TP injection for 1 hour. Cardiac signal intensity (SI) increased more than 70% after Mn-TP injection and remained nearly unchanged 1 hour after injection. Myocardial T1 was 517 +/- 49 msec in eight control rats and 282 +/- 61 msec (P less than .001) in six rats 81 +/- 0 minutes after injection. Nine rats underwent occlusion of the left anterior descending coronary artery prior to MR imaging. Images were obtained before and 15, 30, and 60 minutes after Mn-TP injection. In normal myocardium, SI increased up to 82% and remained elevated for 1 hour. In ischemic myocardium, SI rose 11%, leading to a marked contrast between the two tissue zones. T1 was also different in the two regions: In normal tissue, it was 206 msec +/- 54; in ischemic tissue, 338 +/- 82 (P less than .001). With T1-weighted MR imaging, Mn-TP showed a potential for delineating the jeopardized area after acute myocardial ischemia.     

Pharmacokinetics and distribution of a biodegradable drug-carrier

This paper describes tissue distribution, blood clearance and excretion of biodegradable cyanoacrylic nanoparticles.After intravenous administration, nanoparticles were rapidly cleared from the blood stream and concentrated mainly in the reticuloendothelial system. When administrated subcutaneously, nanoparticles seemed to avoid the liver and the spleen whereas they concentrated in the gut wall.Whole body autoradiography performed on Lewis Lung carcinoma-bearing mice showed progressive accumulation of the carrier in tumoral tissue. Furthermore a high level of radioactivity was found in the metastatic lungs of cancerous animals, whereas no lung accumulation was observed in healthy mice. Data are given concerning the enzymatic contribution to the degradation of the nanoparticles in vivo.