phosphorus-radioisotopes and Arterial-Occlusive-Diseases

By definition, idiopathic erythrocytosis (IE) applies to a group of patients characterised by having a measured RCM above their predicted normal range (an absolute erythrocytosis) and following investigation do not have a form of primary or secondary erythrocytosis. Patients with IE are heterogenous. The possibilities include physiological variation, 'early' polycythaemia vera (10-15% develop clear features of PV over a few years), unrecognized congenital erythrocytosis, unrecognized or unrecognizable secondary acquired erythrocytosis or a currently undescribed form of primary or secondary erythrocytosis. Patients are more commonly male with a median age at presentation of 55-60 years. Approximately half of the patients present with vascular occlusive complications. Retrospective evidence indicates that vascular occlusion occurs less frequently when the PCV is controlled at normal levels. Venesection is the treatment of choice to lower the PCV. As a general approach to management, all patients with a PCV above 0.54 should be venesected to a PCV less than 0.45. This target PCV should also apply to patients with lesser degrees of raised PCV who have additional other risk factors for vascular occlusion.

Topics: Aged; Arterial Occlusive Diseases; Bone Marrow; Chlorambucil; Diagnosis, Differential; Endocrine System Diseases; Erythrocyte Volume; Erythroid Precursor Cells; Erythropoietin; Genetic Predisposition to Disease; Humans; Hypoxia; Kidney Diseases; Leukemia; Leukemia, Radiation-Induced; Middle Aged; Phosphorus Radioisotopes; Polycythemia; Polycythemia Vera; Receptors, Erythropoietin; Sequence Deletion; Smoking; Stroke

Beta radiation prevents recanalization after coil embolization. We sought to determine the effects of varying coil caliber, length, activity of 32P per centimeter of coil or per volume, and spatial distribution of coils on recanalization.. We studied the angiographic evolution of 81 canine maxillary, cervical, and vertebral arteries implanted with a variety of nonradioactive (n=29 arteries) or radioactive (n=52) devices. We compared 1- or 2-caliber 0.015 or 0.010 coils ion-implanted or not with 3 different activity levels (0.05 to 0.08, 0.06 to 0.12, 0.18 to 0.32 microCi/cm) of 32P and totaling 4, 8, and 16 cm in length for the same arterial volume. We also compared inhibition of recanalization by beta radiation delivered by stents, after coil occlusion proximal to or within the stent, with that delivered by coils placed within nonradioactive stents. We finally studied the angiographic evolution of canine lateral wall carotid aneurysms treated with 1 or 2 stents of various activity levels positioned inside the parent artery across the neck. Animals were killed at 4 and 12 weeks for macroscopic photography and pathological examination.. All arteries (29 of 29) occluded with nonradioactive devices were recanalized, while 49 of 52 arteries (94%) implanted with 32P devices were occluded at 4 weeks. All aneurysms treated with stents, radioactive or not, demonstrated residual filling of the sac or of channels leading to the aneurysms at follow-up angiography at 4 weeks.. The recanalization process found in the canine arterial occlusion model is minimally affected by coil caliber, number, and length or packing density. Beta radiation reliably inhibits this process, but thrombosis is an essential condition for the efficacy of a radioactive coil strategy.

Topics: Aneurysm; Animals; Arterial Occlusive Diseases; Arteries; Beta Particles; Carotid Artery Diseases; Carotid Artery Thrombosis; Carotid Artery, Common; Combined Modality Therapy; Disease Models, Animal; Dogs; Dose-Response Relationship, Drug; Drug Implants; Embolization, Therapeutic; Endothelium, Vascular; Equipment Design; Maxillary Artery; Neck; Phosphorus Radioisotopes; Radiotherapy Dosage; Recurrence; Single-Blind Method; Stents; Vertebral Artery

The dose at varying distances from the surface of an infinite cylinder containing 90Y, 32P and 188Re respectively is calculated using published scaled point dose kernels for these three radionuclides. It is shown that all are suitable radionuclides for use in the irradiation of arteries subsequent to balloon angioplasty. All three may be used as a radioactive liquid in the angioplasty balloon, thereby simplifying the procedure and enabling a uniform radiation dose to be given to the arterial wall. It is however shown that there is a rapid reduction in dose with distance from the arterial wall which demands careful specification of the prescribed radiation dose. A similar rapid reduction with distance is also found with a central radioactive wire or with a radioactive stent containing the same radionuclides.

Topics: Angioplasty, Balloon; Arterial Occlusive Diseases; Arteries; Beta Particles; Humans; Phosphorus Radioisotopes; Radioisotopes; Radiotherapy Dosage; Rhenium; Yttrium Radioisotopes

Using 31P nuclear magnetic resonance spectroscopy of the calf muscle, the authors studied patients with peripheral arterial occlusive disease. They studied PCr depletion and intracellular pH during aerobic exercise in patients and controls. The phosphocreatine (PCr) index ([PCr]/([PCr] + [Pi])) at rest was correlated with blood flow measured by plethysmography. During aerobic exercise a greater decrease in pH was obtained in patients (p < 0.03). They also studied the work necessary to reach a PCr index = 0.5 during ischemic exercise. This workload was lower in patients than in controls: 32.99 +/- 3.04 J vs 58.89 +/- 8.55 J, p < 0.05. After vasodilator therapy the workload was improved in patients: 32.99 +/- 3.04 J vs 38.85 +/- 3.54 J, p < 0.05. These results suggest that therapy resulted in improved tissue perfusion in patients.

Topics: Arterial Occlusive Diseases; Exercise; Humans; Hydrogen-Ion Concentration; Intermittent Claudication; Ischemia; Leg; Magnetic Resonance Spectroscopy; Middle Aged; Oxidative Phosphorylation; Phosphocreatine; Phosphorus Radioisotopes; Vasodilator Agents

Muscle metabolism was measured in 7 patients with arterial occlusive disease and symptoms of intermittent claudication both before and after percutaneous vascular neurolysis by means of dynamic 31P-MR spectroscopy. Phosphorus spectra of the involved calf muscles were determined before, during and after defined treadmill exercise. In addition to pH values the phosphocreatine content was measured during activity and recovery phases. There was close correlation in these patients between the increase in claudication distance and more rapid regeneration of phosphocreatine following neurolysis. However, none of the patients achieved normal values of phosphate metabolism. By means of the non-invasive 31P-MR spectroscopy it was possible for the first time to demonstrate the biochemical changes associated with neurolytic lumbar sympathetic blockade.

Topics: Adult; Aged; Aged, 80 and over; Arterial Occlusive Diseases; Energy Metabolism; Exercise Test; Female; Humans; Intermittent Claudication; Leg; Magnetic Resonance Spectroscopy; Male; Middle Aged; Muscles; Phosphorus Radioisotopes