strontium-radioisotopes and Hyperemia

To evaluate the effectiveness and safety of postoperative low single-dose of beta-irradiation (β-RT) in pterygium comparing conjunctival autograft (CAG) surgery with CAG plus adjuvant β-RT in a randomized clinical trial.. This trial was designed as a prospective, randomized, single-center study. Surgery was performed in all cases according to the CAG technique. One hundred and eight pterygia were postoperatively randomized to CAG + β-RT or CAG alone. In the case of β-RT, a (90) Sr eye applicator was used to deliver 10 Gy to the sclera surface at a dose rate of between 200 and 250 cGy/min. After treatment, both an ophthalmologist and a radiation oncologist performed the follow-up examinations. The accumulated data were analyzed using a group sequential test.. Between February 2008 and September 2008, 116 eyes with primary pterygium were operated on according to the trial protocol. Adjuvant treatment was performed within 24 h postoperatively. Eight patients were lost to follow-up, resulting in 108 patients who could be analyzed. At a mean follow-up of 18 months (range, 8-33), in the 54 eyes randomized to receive CAG + β-RT, 5 relapses occurred compared with 12 recurrences in the 54 eyes in CAG, for a crude control rate of 90.8 % vs. 78%; p = 0.032, respectively. The treatment complications as hyperemia, total dehiscence of the autograft and dellen were significantly more frequent in the CAG (p < 0.05). The arm of β-RT resulted in better cosmetic results and improves of symptoms than CAG.. A low single-dose of β-RT of 10 Gy after CAG surgery was a simple, effective, and safe treatment that reduced the risk of primary pterygium recurrence, improved symptoms after surgery, resulting in a better cosmetic effect than only CAG.

Topics: Adult; Aged; Aged, 80 and over; Conjunctiva; Female; Follow-Up Studies; Humans; Hyperemia; Male; Middle Aged; Prospective Studies; Pterygium; Radiotherapy Dosage; Radiotherapy, Adjuvant; Recurrence; Strontium Radioisotopes; Surgical Wound Dehiscence; Treatment Outcome; Young Adult

The authors draw attention to the danger of the development of hyperaemia because of the possible influence of free oxygen radicals during the hypoxic period on brain cells. Using radioactive microparticles of 85Sr the authors assessed the cardiac minute volume and blood flow through the medulla oblongata, cerebellum, subcortical area and cerebral cortex in adult laboratory rats 20 hours after 2-minute ischaemia induced by positive radial acceleration of 10 G. The results indicate an increase of the local blood supply in the investigated parts of the brain, although lower than after 8-hour exposure to high altitude hypoxia at 7000 m.

Topics: Animals; Brain Ischemia; Cerebrovascular Circulation; Female; Hyperemia; Hypoxia; Male; Radionuclide Imaging; Rats; Strontium Radioisotopes

Myocardial perfusion imaging after administration of the potent coronary vasodilator ethyl adenosine-5'-carboxylate, which increases flow to normal areas in excess of that to areas supplied by subcritically stenosed vessels, was investigated as a nonischemia-producing stimulus for detecting subcritical coronary stenosis. Preliminary studies in 10 dogs with reactive hyperemia were performed with thallium-201 and potassium-43 to determine which tracer was a better indicator of increased flow. Neither agent was a linear indicator of increased flow caused by reactive hyperemia but thallium-201, because of its imaging characteristics, was selected as a flow indicator after administration of ethyl adenosine. Five dogs were studied after placement of a subcritical stenosis on the left circumflex coronary artery. Strontium-85 microspheres were injected into the left atrium after placement of the stenosis to verify that changes in resting blood flow were only minimal. Thereafter, intravenous administration of ethyl adenosine was followed by injection of chromium-51-labeled microspheres into the left atrium and intravenous administration of thallium-201. The mean ratio of left circumflex to left anterior descending coronary arterial flow was 0.96 +/- 0.16 for the control experiment after subcritical stenosis; after administration of the vasodilator the ratio of activity levels in the two arteries was 0.43 +/- 0.09 with the chromium-51 microspheres and 0.56 +/- 0.07 with thallium-201. Imaging performed in three additional dogs after injection of microspheres in the presence of subcritical stenosis revealed a normal pattern, whereas imaging after administration of the vasodilator and thallium-201 revealed a perfusion deficit. In two additional dogs without subcritical stenosis, thallium was administered after injection of ethyl adenosine to determine that the drug alone did not cause perfusion deficits. The perfusion scans in these two dogs were normal. These studies suggest that a coronary vasodilator and thallium-201 myocardial imaging can be used to detect subcritical coronary stenosis.

Topics: Adenosine; Animals; Blood Pressure; Coronary Circulation; Coronary Disease; Dogs; Heart Rate; Hyperemia; Potassium Radioisotopes; Radioisotopes; Radionuclide Imaging; Strontium Radioisotopes; Thallium; Vasodilator Agents

The enhanced vascular permeability induced by histamine or bradykinin in the skin of the guinea-pig and rabbit was significantly augmented by small amounts of prostaglandins of the E type. When injected alone these prostaglandins had little effect on vascular permeability. Furthermore, E type prostaglandins were found to be more potent at inducing hyperemia than either histamine or bradykinin. Prostaglandin F2alpha did not enhance the vascular permeability induced by histamine or bradykinin nor did it produce hyperemia in the skin. In the rat, prostaglandins alone enhanced vascular permeability but they also increased the effect of histamine, serotonin and bradykinin. Using 85Sr-microspheres to measure blood flow a correlation was found between the degree of hyperemia produced by prostaglandins and the degree to which they augmented enhanced vascular permeability due to histamine, serotonin or bradykinin. Prostaglandins therefore can directly mimic the hyperemia of the inflammatory process and can also modulate the changes in vascular permeability caused by other mediators of inflammation.

Topics: Animals; Bradykinin; Capillary Permeability; Guinea Pigs; Histamine; Hyperemia; Iodine Radioisotopes; Microspheres; Prostaglandins; Prostaglandins E; Prostaglandins F; Rabbits; Rats; Strontium Radioisotopes

In normal rabbit bones, as well as in callus, there is significantly more uptake of 18F than of 85Sr or 99mTc-EHDP. Extraosseous abscesses show significantly higher uptake of 99mTc than of 18F or 85Sr. In the presence of hyeraemia, there is no significant difference in the uptake of the various osteotropic radio-nucleides.

Topics: Animals; Bone and Bones; Bony Callus; Fluorine; Hyperemia; Rabbits; Radioisotopes; Radionuclide Imaging; Strontium Radioisotopes; Technetium

A variety of dermal lesions produced by PGE1, tuberculin, and allogeneic lymphocytes were induced in rabbits, guinea pigs, and sheep, respectively. Microspheres labeled with 85Sr were injected into the ascending aorta, and the distribution of radioactivity in the lesions, saline control sites, and various major organs was assessed. It was concluded that the trapping of the microspheres was related to the degree of hyperemia induced, and that this technique enabled a quantitative measure of the blood flow. PGE1 was found to be a potent mediator of hyperemia and to have a significant effect on the blood flow at a dose of 1 ng. The blood flow to cellular hypersensitivity reactions was measured and the capacity of the skin to accomodate a large increase in flow during the inflammatory response was established.

Topics: Animals; Bradykinin; Dermatitis; Female; Guinea Pigs; Histamine; Hyperemia; Lymphocyte Transfusion; Microspheres; Prostaglandins E; Rabbits; Regional Blood Flow; Sheep; Skin; Strontium Radioisotopes; Transplantation, Homologous; Tuberculin

Topics: Animals; Blood Flow Velocity; Cardiopulmonary Bypass; Cerium Isotopes; Coronary Circulation; Coronary Disease; Dogs; Electric Stimulation; Heart Ventricles; Hydrogen-Ion Concentration; Hyperemia; Lactates; Myocardium; Oxygen Consumption; Potassium; Radioisotopes; Rheology; Scandium; Strontium Radioisotopes; Time Factors; Vascular Resistance; Ventricular Fibrillation

This study was designed to determine whether coronary vasodilation distal to a flow-limiting coronary artery stenosis could result in redistribution of myocardial blood flow to produce subendocardial underperfusion. Studies were performed in 10 awake dogs chronically prepared with electromagnetic flow-meters and hydraulic occluders on the left circumflex coronary artery. Regional myocardial blood flow was measured using radionuclide-labeled microspheres, 7-10 mum in diameter, injected into the left atrium. A 5(-s) coronary artery occlusion was followed by reactive hyperemia with excess inflow of arterial blood effecting 375+/-20% repayment of the blood flow debt incurred during occlusion. When, after a 5(-s) occlusion, the occluder was only partially released to hold arterial inflow to the preocclusion level for 20 s before complete release, the delayed reactive hyperemia was augmented (mean blood flow repayment = 610+/-45%, P < 0.01). This augmentation of the reactive hyperemia suggested that ischemia was continuing during the interval of coronary vasodilation when coronary inflow was at the preocclusion level. Measurements of regional myocardial blood flow demonstrated that endocardial flow slightly exceeded epicardial flow during control conditions. When arterial inflow was limited to the preocclusion rate during vasodilation after a 5(-s) total coronary artery occlusion, however, flow to the subepicardial myocardium was increased at the expense of underperfusion of the subendocardial myocardium. Thus, in the presence of a flow-limiting proximal coronary artery stenosis, ischemia-induced coronary vasodilation resulted in redistribution of myocardial blood flow with production of subendocardial ischemia in the presence of a net volume of arterial inflow which, if properly distributed, would have been adequate to prevent myocardial ischemia.

Topics: Animals; Cerium Isotopes; Computers; Coronary Circulation; Coronary Disease; Coronary Vessels; Dogs; Electromagnetic Phenomena; Endocardium; Heart Rate; Hemodynamics; Hyperemia; Ischemia; Radioisotopes; Rheology; Scandium; Spectrometry, Gamma; Strontium Radioisotopes

Topics: Animals; Blood; Blood Flow Velocity; Cardiopulmonary Bypass; Cerium Isotopes; Coronary Circulation; Coronary Disease; Dogs; Electric Stimulation; Heart Ventricles; Hydrogen-Ion Concentration; Hyperemia; Lactates; Myocardium; Oxygen Consumption; Potassium; Radioisotopes; Scandium; Strontium Radioisotopes; Ventricular Fibrillation

Topics: Albumins; Animals; Coronary Circulation; Coronary Disease; Dogs; Electric Stimulation; Hyperemia; Microspheres; Potassium Isotopes; Radioisotopes; Radionuclide Imaging; Regional Blood Flow; Rest; Strontium Radioisotopes; Technetium