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Biomedical subjects

U Y Ryo

Publications and source records attributed to U Y Ryo.

At least 91 records · Page 5Linked to original sources
PubMed1976

Radionuclide venography: significance of delayed washout; visualization of the saphenous system.

Venograms were obtained on dogs in which venous thrombosis had been surgically induced. Radionuclide venograms, obtained after injection of 99mTc-labeled microspheres or macroaggregated albumin, showed decreased radioactivity over the areas of venous thrombosis and increased radioactivity over areas of venous stasis. Scintigrams of veins excised after an injection of labeled particles did not delineate thrombi, areas of crush-injured vein, or the venous valves. Delay in the washout of radioactivity on a venogram indicates stasis due to impeded venous flow in the area of thrombosis. A modified technique was developed to obtain simultaneous images of the superficial and deep veins of the leg. Visualization of the superficial veins not only permits detection of superficial abnormalities, but also assists interpretation of the venographic observations of the deep veins.

Animals↗
PubMed1976

Radionuclide angiography with 99m technetium-RBCs.

When properly labeled 99mTc-RBCs are injected into a patient, these labeled cells are fairly stable in the circulation thus allowing scintigraphic studies on cardiovascular system. Among various modified techniques published for 99mTc-RBCs labeling, incubation of RBCs with 99mTc pertechnetate then with tin yielded 99mTc-RBCs most stable in the circulation. Average labeling efficiency of 99mTc-RBCs was 66%. After an injection of about 10 mCi 99mTc-RBCs, clear images of the heart chambers and major vessels could be obtained using a gamma camera. Resolution of vascular structures improved significantly when images were taken using gamma camera equipped with pinhole collimator. Radionuclide angiography with 99mTc-RBCs was very useful in detection of abdominal aortic aneurysm, evaluation of mediastinal mass--thoracic aortic aneurysm, and detection of abnormality in a smaller vessel such as carotid artery. Advantages of this procedure are (1) the technique is simple and noninvasive; (2) it has capability of functional evaluation by obtaining flow study; and (3) multiple and repetitive static views can be obtained even several hours after an injection.

Aged↗
PubMed1975

Bronchial sensitivity to methacholine in current and former asthmatic and allergic rhinitis patients and control subjects.

Ninety-eight subjects underwent methacholine (Mecholyl) aerosol challenge at a concentration of 5 mg/ml. All atopic groups differed significantly in their bronchial response to Mecholyl compared to nonatopic control subjects. Nineteen normal subjects had a mean decrease of 11.4% in forced expiratory volume in one second (FEV1) with 128 Mecholyl inhalations and 2 decreased by greater than 20%. Fifteen of 27 allergic rhinitis patients had a positive response to Mecholyl as defined by a decrease in FEV1 greater than 20%. Four of these responders developed greater diminution in FEV1 response with additional Mecholyl inhalations in a manner similar to that seen in the asthmatic patients. Eighteen current asthmatics showed the greatest bronchial sensitivity to Mecholyl with a mean 33% decrease in FEV1 at 4.5 inhalations. One hundred per cent of current asthmatics and 82% (28 of 34) of former asthmatics (free of asthma symptoms for 1 to 20 yr) showed positive response to Mecholyl. A 20% decrease in FEV1 with a total of 20 inhalations or less is consistent with a diagnosis of "current asthma," and even 20 of 34 former asthmatics responded in this manner. The Mecholyl aerosol test can be used to diagnose previous and current asthma and may be of value in predicting asthma in hay fever patients.

Asthma↗
PubMed1975

99mTc-pertechnetate thyroid scintigraphy in patients predisposed to thyroid neoplasms by prior radiotherapy to the head and neck.

Histories, physical examinations and 99mTc-pertechnetate imaging were used to evaluate 1,452 persons who had had x-ray therapy to the neck region for benign conditions 18 to 35 years previously. Thyroid abnormalities were found in 301 patients (21%) and thyroid malignancy was found in 29% of 193 patients with abnormal studies who were explored surgically. Thyroid imaging detected 96% of these abnormalities, 40% of which would not have been unequivocally established by physical examination alone. Nuclear imaging could not distinguish benign from malignant lesions.

Adenocarcinoma↗
PubMed1975

Visualization of nonvascular cranial tumor in cerebral flow study: case report.

Unusual results were obtained from a cerebral blood flow study and a brain scan performed on a patient with an uncommon, nonvascular scalp tumor eventually identified as a proliferating trichilemmal cyst with acanthosis. The tumor accumulated the radionuclide during the early phase of the cerebral flow study, and the increased radioactivity was persistent, being prominently observable in a scan made 3 min and 2 hr after the radionuclide injection. This unusual, positive finding in a cerebral blood flow study of a nonvascular tumor was thought to be a consequence of the higher counting efficiency resulting from the lack of shielding by the skull and from the larger volume of the tumor tissue.

Aged↗
PubMed1975

Myocardial uptake of labeled oleic and linoleic acids.

Oleic acid labeled with 14C, (14C-OA) or 131I (131I-OA) and 131I-labeled linoleic acid (131I-LOA) were administered intravenously to rats and tissue distribution studies completed at various time intervals from 5 to 60 min. Tissue distribution of 131-I-labeled oleic acid or linoleic acid was also studied in dogs at 5- and 30-min time intervals after intravenous administration of the tracer dose. There were distinct differences in the patterns of tissue distribution between 14C-OA, 131I-OA, and 131I-LOA. Radioactivity concentration in the myocardium was the highest at all time intervals in the rats given 131I-OA only. In dogs, the myocardial uptake of 131I-OA was significantly higher than the radioactivity in the blood or other tissues at 30 min after injection. The disappearance rates of 131I-OA and 131I-LOA were almost identical but myocardial concentration of 131I-LOA at 30 min after the dose in the dog was half that of 131I-OA whereas 131I-LOA liver concentration was higher than that of 131I-OA. Since the concentrations of our formulated 131I-OA in the blood and in the myocardium are both highest at the earlier intervals, it should be difficult to detect myocardial ischemia or infarction with 131I-OA scanning.

Animals↗
PubMed1975

Tissue distribution of 14C-, 125I-, and 131I-diphenylhydantoin in the toadfish, rat, and human with insulinomas.

Carbon-14-diphenylhydantoin (DPH) concentrated maximally in pancreatic islet cells of the toadfish 10 min after its intravenous administration. The islet cell-to-acinar-tissue ratio at this time was 6:1. The islet cell-to-liver ratio was 20:1. Iodine-125-paroiodo-DPH at 10 min in the toadfish showed an islet cell-to-acinar-tissue ratio of 1.7:1 and an islet cell-to-liver ratio of 2.3:1. When 14C-DPH was given to four patients 10-17 min before removal of norma pancreatic tissue and of an insulinoma in three of the patients, the concentration of radioactivity in the insulinoma was never greater than in the pancreas and concentrations in insulinoma and pancreas were always less than in liver in the same individual. Forty-five to 90 min after administration of 131I-DPH, the liver and pancreas were delineated in three patients but the insulinoma was not imaged. Five days after administration of 131I-DPH, the concentration of 131I radioactivity in excised tissue was greater in the insulinomas than in the pancreas of two patient but not sufficient to produce positive images of the insulinoma in the pancreas.

Adenoma, Islet Cell↗
PubMed1975

Relative tissue distribution of radioactivity in rats with endocrine "autonomous" breast carcinomas after 3H-,99mTc-, and 64Cu-bleomycin.

The localization of 64Cu-, 3H-, and 99mTc-labeled bleomycin was studied in tissues of Fisher rats bearing an endocrine autonomous breast tumor. The 64Cu-bleomycin showed a greater uptake than 3H- and 99mTc-bleomycin in the breast tumor at all time intervals studied, from 2 to 72 hr after the tracer. This same differential uptake was shared by the liver and kidney.

Animals↗