Radioisotopes (Total 24601 Papers Found)

The extensive use of depleted uranium (DU) in today's society results in the increase of the number of human population exposed to this radionuclide. The aim of this work was to investigate in vivo the effects of a chronic exposure to DU on vitamin D(3) metabolism, a hormone essential in mineral and bone homeostasis. The experiments were carried out in rats after a chronic contamination for 9 months by DU through drinking water at 40 mg/L (1 mg/rat/day). This dose corresponds to the double of hi ...
Cholecystokinin (CCK) receptors are overexpressed in numerous human cancers, like medullary thyroid carcinomas, small cell lung cancers and stromal ovarian cancers. The specific receptor-binding property of the endogenous ligands for these receptors can be exploited by labeling peptides with a radionuclide and using these as carriers to guide the radioactivity to the tissues that express the receptors. In this way, tumors can be visualized using positron emission tomography and single photon emi ...
In the long term after the Chernobyl accident the introduction of systems of countermeasures in agriculture must be based on the optimization principle. To implement this principle, a concept was used of evaluation of the effectiveness of countermeasures based on a cost-benefit analysis. Countermeasure options were developed separately for collective and private sectors of rural settlements. For each type of farming a range of countermeasures were defined and the optimal ones were identified. Th ...
A new way of statistical pulsation measurements by radioisotope technique is described. It is an alternative to the existing stream control methods and allows to improve accuracy of measurements. The effect of harmful substances transported in crude oil on the level of production at oil companies is dealt with in the article. ...
The purpose of the study was to assess the relationship between left and right ventricular function measured at rest and maximal exercise capacity in patients with recent acute myocardial infarction (AMI). Forty-three male patients (Killip Class I, n = 36; Killip Class II, n = 7) with a wide range of left ventricular (LV) function and size underwent graded bicycle exercise testing less than 4 weeks after AMI (mean 21 days, 17-27). None of the patients had exercise limiting factors other than dys ...
on a liquid diet containing either 9.86 (n = 9) or 0 (i = 9) mEq NaCl/daily portion for 2 wk. Labeled antibody was injected and the diets were reversed. After an additional 2 wk period, antibody labeled with a different radionuclide was injected and the animals were sacrificed. Fractional plasma flow distribution was then calculated for each dietary period. No change in flow to any cortical region could be detected. In six additional awake rats on identical dietary regimen, total plasma flow was ...
Right and left ventricular ejection fractions (RVEF and LVEF) were studied at rest, during exercise, and in the immediate post-exercise period (recovery) in 23 patients treated with doxorubicin. Ejection fractions were determined using equilibrium gated radionuclide angiography and non-interactive computer processing. Two effects of doxorubicin emerged: (1) The LVEF at rest and the maximal LVEF reached during the stress test decreased as a function of the cumulative dose expressed in mg/m2. (2) ...
-A time-resolved fluoroimmunoassay (TR-FIA) marketed for measuring cortisol in human sera was evaluated and validated for use in the quantification of plasma cortisol concentrations of channel catfish Ictalurus punctatus. Time-resolved fluoroimmunoassays provide non-isotopic alternatives to the use of radioimmunoassays (RIA). The evaluated TRFIA satisfied strict criteria of precision (intra-assay coefficients of variation (CV) < 7%) and reproducibility (inter-assay CV 5 9%). Accuracy of the T ...
Six-week-old male Wistar rats were administrated the radioisotopes of five trace elements (iron, zinc, copper, manganese and iodine) intravenously in order to elucidate the significance of their pharmacokinetics by noncompartmental analysis. The mean residence time (MRT) and variance of residence time (VRT) increased in the order Mn, Cu, I, Fe and Zn. Neither MRT nor VRT indicated any statistical significance between I and Fe. These results suggested that Mn and Cu were voided rapidly from the p ...
In Japan, clinical application of unsealed radioisotopes is strictly regulated. Especially in the field of therapy, we are allowed to use only Na131I at present. Under such circumstances, the present status of therapeutic nuclear medicine in Japan was surveyed by means of a nation-wide questionnaire, conducted in 193 hospitals. Then, 113 hospitals replied to such questionnaire (recovery rate: 58.5%), and it was found that in 77 hospitals, radioisotope therapy is being performed for Graves' disea ...
In radionuclide treatment, tumor cells are primarily destroyed by charged particles emitted by the compound while associated higher energy photons are used to image the tumor in order to determine radiation dose and monitor shrinkage. However, the higher energy photons are difficult to image with conventional collimated Anger cameras, since a tradeoff exists between resolution and sensitivity, and the collimator septal penetration and scattering is increased due to the high energy photons. This ...
THE ability of Unio (Mollusca, Lamellibranehia) to concentrate manganese has been known for more than fifty years1. High concentrations of this element in Unionidae were also reported more recently by Vinogradov2 and by Merlini3. In September 1960, manganese-54 was found in Unio mancus var. elongatulus (Pfeiffer) collected in Lake Maggiore and in nearby Lake Varese. It could not be detected in fall-out, lake water, sediment, rooted aquatic plants, gastropods or fish. After having ascertained tha ...
We sought to develop a practical, reproducible and clinically translatable method of radiolabeling serum albumins with fluorine-18 for use as a PET blood pool imaging agent in animals and man. Fluorine-18 radiolabeled fluoronicotinic acid-2,3,5,6-tetrafluorophenyl ester, [(18)F]F-Py-TFP was prepared first by the reaction of its quaternary ammonium triflate precursor with [(18)F]tetrabutylammonium fluoride ([(18)F]TBAF) according to a previously published method for peptides, with minor modificat ...
PURPOSE A high percentage of paragangliomas express somatostatin receptors that can be utilized for targeted radioisotope therapy. The aim of this study was to describe and discuss the challenges of treating these tumors with (177)Lu-[DOTA(0),Tyr(3)]octreotate (DOTATATE) radioisotope therapy using established protocols. METHODS AND RESULTS Three paraganglioma patients were treated with 4-5 cycles of (177)Lu-DOTATATE and were evaluated for side effects and response to therapy. Two of the three ...
Severe algal blooms in Lake Winnipeg since the late 1990s have been attributed to increased watershed nutrient loading, much of which is associated with suspended particles. Within-lake transport and fate of this nutrient fraction and the importance of internal loading via resuspension, however, are unknown. We measured radioisotopes (7Be, 210Pb, 137Cs), metal and nutrient contents of suspended solids in major tributaries and lake-water, in sediment traps and in bottom sediments to estimate sedi ...
The association of the arene ruthenium metallacycle [Ru4(p-cymene)4(bpe)2(donq)2][DOS]4 (bpe = 1,2-bis(4-pyridyl)ethylene, donq = 5,8-dioxydo-1,4-naphtoquinonato, DOS = dodecyl sulfate) with pyrenyl-functionalized poly(arylester) dendrimers bearing cyanobiphenyl end-groups is reported. The supramolecular dendritic systems display mesomorphic properties as revealed by polarized optical microscopy, differential scanning calorimetry and small-angle X-ray scattering measurements. The multicomponent ...
diameter of the intact canine left ventricular cavity. J Appl Physiol 36: 496, 1974 30. Sasayama S, Franklin D, Ross J Jr, Kemper WS, McKown D: Dynamic change in left ventricular wall thickness and their use in analyzing cardiac function in the conscious dog. Am J Cardiol 38: 870, 1976 31. Karliner JS, Williams D, Gorwit J, Crawford MH, O'Rourke RA: Left ventricular performance in patients with left ventricular hypertrophy caused by systemic arterial hypertension. Br Heart J 39: 1239, 1977 32. T ...
Cavernous angiomas are a rare but important clinical entity because of their potential curability. Three patients who had intracranial cavernous angiomas confirmed at surgery are presented. Preoperative recognition is greatly aided by a tendency to calcify, as identified both by skull films and more sensitively by computed tomography. A well demarcated collection of rounded densities of CT scanning, showing mild contrast enhancement and no significant mass effect, should suggest the possibility ...
Somatostatin and other neuropeptides are expressed in tumors originating from neuronal precursors and paraganglia, namely medulloblastoma, central Primitive Neuro-Ectodermal Tumors (cPNETs), neurocytoma, gangliocytoma. olfactory neuroblastoma, paraganglioma. In medulloblastoma, the most common malignant tumor in childhood, there is an extensive expression of somatostatin in addition to somatostatin receptors (SSTR) type 2. Although density of SSTR-2 and intensity of expression of somatostatin ge ...
We report on the development of a sensitive and selective deoxyribonucleic acid (DNA) demethylase (using MBD2 as an example) activity assay by coupling the fluorescence quenching of graphene oxide (GO) with the site-specific cleavage of HpaII endonuclease to improve the selectivity. This approach was developed by designing a single-stranded probe (P1) that carries a binding region to facilitate the interaction with GO, which induces fluorescence quenching of the labeled fluorophore (FAM, 6-carbo ...
An important role is reserved for nuclear imaging techniques in the imaging of neuroendocrine tumors (NETs). Somatostatin receptor scintigraphy (SRS) with (111)In-DTPA-octreotide is currently the most important tracer in the diagnosis, staging and selection for peptide receptor radionuclide therapy (PRRT). In the past decade, different positron-emitting tomography (PET) tracers have been developed. The largest group is the (68)Gallium-labeled somatostatin analogs ((68)Ga-SSA). Several studies ha ...
The first Egyptian (ET-RR1) research reactor has been in operation since 1961 at the Egyptian Atomic Energy Authority (EAEA) Inshas site. Therefore, at present, it faces a serious problem due to aging equipment, especially those directly in contact with the environment such as the underground settling tanks of nuclear and radioactive waste. The possible leakage of radionuclides from these aging tanks and their migration to the aquifer was studied using instantaneous release. This study was done ...
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Although the accelerated transport of Tc, Cs, and U within the vadose zone beneath the 200-West Area of the Hanford tank-farm area has been recognized, the mechanisms responsible for the vertical migration of the radionuclides is unclear. Does horizontal stratification enchance the lateral movement of contaminants, which in turn enhances vertical perferential flow due to perched water dynamics? Do physical heterogeneties, such as stratification and pore regime connectivity, influence the retarda ...
BACKGROUND Free colon and jejunal flaps have been described as reliable and safe conduits for pharyngoesophageal reconstruction. Compared with free colon flaps, free jejunum flaps have a smaller diameter and intrinsic peristaltic movement, both of which are considered possible causes of dysphagia. In this investigation, the authors evaluated motility differences in free jejunum and colon flaps using radionuclide esophageal scintigraphy. METHODS Patients who received free jejunum flaps (n = 12) ...
Alpha emitting radioisotopes are promising candidates for radiotherapy of several tumour types due to the high linear energy transfer (LET) of alpha particles in biological tissues. For this purpose research on productions of Ac (via Ra(p,2n)Ac) and of At (via Bi(α,2n)At) is undertaken. The research activities aim at improving production techniques and radiochemical processing yield in order to enhance the availability of these radioisotopes for medical application. Theoretical calculations and ...
In 16 men with normal valvular function (group 1) and 23 men and one woman with isolated aortic regurgitation (group 2) effective stroke was determined by first-pass radionuclide ventriculography. Total left ventricular stroke volume was derived from equilibrium radionuclide ventriculography using a geometric approach for the end-diastolic volume multiplied by the ejection fraction. The difference between the two stroke volumes as a fraction of total left ventricular stroke volume was taken as r ...
PURPOSE Simulated projection images of digital phantoms constructed from CT scans have been widely used for clinical and research applications but their quality and computation speed are not optimal for real-time comparison with the radiography acquired with an x-ray source of different energies. In this paper, the authors performed polyenergetic forward projections using open computing language (OpenCL) in a parallel computing ecosystem consisting of CPU and general purpose graphics processing ...
The development of monoclonal antibodies has permitted the identification of several ovarian-tumor-associated antigens which might serve as targets for serotherapy in vivo. With the exception of antibodies directed against growth factor receptors, unmodified monoclonal reagents must activate complement (C') components or bind effector cells to destroy tumor targets. Antibody-dependent cell-mediated cytotoxicity (ADCC) may be particularly important for eliminating tumor cells in vivo. A shortage ...
The distribution of calcitonin (CT) binding sites in serial sections of the rat brain and spinal cord has been examined by an 'in vitro' autoradiographic technique using a radioisotope-sensitive sheet film and [125]salmon CT. Autoradiograms of the diencephalic region had the highest grain density throughout the entire hypothalamus, with the exception of the nuclei ventromedialis, posterior and mammillaris, which were not labeled at all. In the brainstem, large amounts of grains were found in the ...
The comparative analysis of frequencies of different type cytogenetic anomalies in voles Microtus oeconomus, Microtus arvalis, Clethrionomys glareolus trapped in territories with different levels of radionuclide contamination inside the 30-km zone of estrangement around the Chernobyl NPP was carried out. Animals with constitutive chromosome abnormalities were not revealed. The frequency of lympocytes with micronuclei was the most universal and sensitive character to chronic low-dose radiation in ...
Since the first tracer study by George C. de Hevesy in 1923, in which he used the tracer principle to study the absorption and translocation of lead nitrate with Pb-212 (1), radionuclides have been used both in vitro and in vivo to trace various biologic processes. The radioisotopes of iodine in particular have played an important role in the early development of nuclear medicine since their use in thyroid metabolism studies (I-131) and radioimmunoassay (I-125). Although I-131 did not have ideal ...
Differentiated thyroid cancer (DTC) is usually curable with surgery, radioactive iodine (RAI), and thyroid-stimulating hormone (TSH) suppression. However, local recurrence and/or distant metastases occur in approximately 15% of cases during follow-up, and nearly two-thirds of these patients will become RAI-refractory (RR-DTC) with a poor prognosis. This review focuses on the most challenging and rapidly evolving aspects of RR-DTC, and we discuss the considerable improvement in more accurately de ...
To evaluate the clinical usefulness of immunoscintigraphy with OC 125 in ovarian carcinoma, we studied 25 patients suspected of having ovarian carcinoma or in follow-up after surgery. Fourteen patients were studied with 131I-OC 125 F(ab')2 and 11 with 111In-OC 125 F(ab')2. No differences were observed with the use of either radionuclide. Global diagnostic indexes obtained were S = 100%, Sp = 44,5% and A = 81%. The low specificity obtained was remarkable: 5 false positive results in two uterine m ...
Right ventricular function was assessed in 24 patients with COPD, at rest and during submaximal exercise, using both technetium-99m (99mTc) blood-pool and krypton-81m (81mKr) equilibrium ventriculography. Technetium-99m right ventricular ejection fraction (RVEF) at rest was lower than 81mKr RVEF (0.39 +/- 0.12 and 0.54 +/- 0.08, respectively; p < 0.001). During submaximal exercise, there was no increase in RVEF using either imaging technique. This observation contrasted with an increase in RV ...
INTRODUCTION Intracavitary treatment of solitary cystic craniopharyngiomas with (32)P is an emerging treatment option, especially for pediatric patients. We have treated two patients with solitary cystic craniopharyngiomas using intraoperative MRI (iMRI)-guided catheter placement. METHODS The optical tracking system of the General Electric Signa SP iMRI system was utilized for preoperative planning and intraoperative catheter tracking during insertion. Intraoperative volumetric imaging was the ...
Previous radiotracer experiments that compared multi-elemental whole organism: water transfer factors among chondrichthyan and teleost fishes, including an ICRP reference flatfish Psetta maxima, demonstrated distinctive contrasts in their bioaccumulation characteristics, with generally elevated bioaccumulation in chondrichthyans. These results supported a hypothesis that phylogenetic divergence may influence marine radionuclide transfer factors. This notion has been further evaluated in an amphi ...