indium-oxine and Ischemia

Transplantation of mononuclear cells (MNCs) has previously been tested as a method to induce therapeutic angiogenesis to treat limb ischemia in clinical trials. Non-invasive high resolution imaging is required to track the cells and evaluate clinical relevance after cell transplantation. The hypothesis that MRI can provide in vivo detection and long-term observation of MNCs labeled with manganese contrast-agent was investigated in ischemic rat legs.. The Mn-labeled MNCs were evaluated using 7-tesla high-field magnetic resonance imaging (MRI). Intramuscular transplanted Mn-labeled MNCs were visualized with MRI for at least 7 and up to 21 days after transplantation in the ischemic leg. The distribution of Mn-labeled MNCs was similar to that of ¹¹¹In-labeled MNCs measured with single-photon emission computed tomography (SPECT) and DiI-dyed MNCs with fluorescence microscopy. In addition, at 1-2 days after transplantation the volume of the site injected with intact Mn-labeled MNCs was significantly larger than that injected with dead MNCs, although the dead Mn-labeled MNCs were also found for approximately 2 weeks in the ischemic legs. The area covered by CD31-positive cells (as a marker of capillary endothelial cells) in the intact Mn-MNCs implanted site at 43 days was significantly larger than that at a site implanted with dead Mn-MNCs.. The present Mn-enhanced MRI method enabled visualization of the transplanted area with a 150-175 µm in-plane spatial resolution and allowed the migration of labeled-MNCs to be observed for long periods in the same subject. After further optimization, MRI-based Mn-enhanced cell-tracking could be a useful technique for evaluation of cell therapy both in research and clinical applications.

Topics: Animals; Blood Circulation; Bone Marrow Cells; Cell Tracking; Cell Transplantation; Chlorides; Contrast Media; Hindlimb; Ischemia; Kinetics; Magnetic Resonance Angiography; Magnetic Resonance Imaging; Male; Manganese Compounds; Microscopy, Fluorescence; Organometallic Compounds; Oxyquinoline; Platelet Endothelial Cell Adhesion Molecule-1; Rats; Rats, Wistar; Staining and Labeling; Tomography, Emission-Computed, Single-Photon

Platelet half-life was assessed with autologous 111In-marked platelets in fourteen subjects, four women and ten men, who previously had suffered vascular accidents (myocardial infarction, TIA, stroke or peripheral obstructive arterial disease). Results, compared to findings in low risk subjects showed a statistically significant correlation of platelet half-life to certain pathologies (TIA, stroke) as well as to habits (tobacco, alcohol) and biological variables (age, sex). By and large, data were analogous to those of the current scientific literature in so far as certain factors shorten platelet half-life. A correlation was also found between platelet half-life and time elapsed since the pathological event. Liver sequestration evaluated by total body scintigraphy showed high levels in one case each with a history of stroke, a history of TIA, and a history of peripheral arterial disease, and splenic sequestration in only one case with a history of stroke.

Topics: Adult; Aged; Blood Platelets; Cell Survival; Cerebrovascular Disorders; Coronary Disease; Female; Humans; Indium Radioisotopes; Ischemia; Ischemic Attack, Transient; Male; Middle Aged; Models, Biological; Organometallic Compounds; Oxyquinoline; Peripheral Vascular Diseases

Intestinal wall necrosis without perforation was produced in six dogs. Another group of three dogs served as a control. The histologic findings, the degree of ischemia and scintigraphic images obtained after the infusions of autologous white blood cells labelled with indium-111 oxine were correlated. Positive scans were obtained in all the dogs with proven intestinal ischemia. Negative scans appeared in the dogs without ischemic insult and a false-positive scan were observed in a control dog with diarrhea.

Topics: Animals; Disease Models, Animal; Dogs; Ileum; Indium Radioisotopes; Ischemia; Leukocyte Transfusion; Leukocytes; Necrosis; Organometallic Compounds; Oxyquinoline; Radionuclide Imaging; Time Factors

The feasibility of the use of indium 111 oxine-labeled autologous leukocytes for the diagnosis of ischemic enterocolitis in vivo was examined in an experimental model of ischemia in dogs. A 30-cm segment of small intestine was devascularized by ligating the arteries and veins from the last arcade in 7 dogs. A sham operation was performed in 3 control dogs. 111In oxine-labeled autologous white blood cells were infused 3.5 hours after operation. Anterior and lateral nuclear scanning was performed at 6 and 24 hours postinfusion with a gamma camera equipped with a low-energy magnifying multihole collimator. The animals were killed after 24 hours. The gross and microscopic appearance of the bowel was evaluated. The radioactivity in the serial specimens of the bowel was measured. In vivo scans were positive (ie, increased uptake in the bowel loop) in all dogs with intestinal ischemia at 6 and 24 hours. No significant uptake was noted in control dogs. Rectilinear scan of the bowel removed at autopsy showed a correlation between the area of infarction and tracer accumulation. In addition, there was a progressive decrease in uptake of 111In oxine from the center of the ischemic lesions to the periphery. Forty percent of the total radioactivity was measured at the center of the lesion, whereas only 6.5% was present at 22.5 cm from the center. Thus the ratio between the ischemic and normal tissue was 10:1 (range, 6.5 to 16). These studies demonstrate that 111In oxine-labeled autologous white blood cells can be used for the diagnosis of ischemic enterocolitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Dogs; Enterocolitis; Indium Radioisotopes; Intestines; Ischemia; Leukocytes; Organometallic Compounds; Oxyquinoline; Radionuclide Imaging

The pathophysiological response to peripheral percutaneous transluminal balloon angioplasty in 20 patients was investigated using 111-Indium labelled platelets. Platelet deposition was quantified by measuring the degree of radioactivity uptake at angioplasty and control sites using a computer linked system and expressing the uptake as a ratio of angioplasty/control. Following platelet labelling, scans were performed before angioplasty and at 1, 24 and 48 h after angioplasty. To assess patency of the angioplasty, ankle brachial Doppler pressure indices were performed and supported by repeat angiograms if doubt of patency existed. All patients were followed-up at 1 week, 1 month and 6 months to correlate the degree of early platelet uptake with failure. The mean +/- sem platelet radioactivity ratio at the angioplasty site increased from 1.1 +/- 0.1 prior to the procedure to a peak of 2.1 +/- 0.3 at 1 h (p less than 0.01), 1.6 +/- 0.2 at 24 h (p less than 0.05), and 1.7 +/- 0.3 at 48 h (p less than 0.05). Angioplasties that failed within 6 months tended to have a higher maximum early platelet uptake (3.1 +/- 0.6) compared to successful angioplasties (1.9 +/- 0.3) but the difference was not significant in the numbers studied. This study provides a suitable model to assess the role of platelet accumulation in angioplasty failure and the influence of various antiplatelet regimes.

Topics: Adult; Aged; Aged, 80 and over; Female; Humans; Indium Radioisotopes; Ischemia; Leg; Male; Middle Aged; Organometallic Compounds; Oxyquinoline; Platelet Aggregation; Postoperative Complications; Radionuclide Imaging; Recurrence; Thrombosis