Search results for "Radioisotope"

Effects of endothelin-1 on the cerebrovascular bed of the goat.

1991

Abstract The aim of the present study was to analyze the effects of endothelin-1 (ET-1) in the cerebrovascular bed of the goat, the importance of endothelial integrity and the contribution of extracellular Ca2+ to these responses. We measured isometric tension and 45Ca2+ uptake in isolated middle cerebral arteries, and cerebral blood flow (CBF) in unanesthetized animals. ET-1 elicited concentration-dependent contractions which were potentiated in arteries without endothelium. Ca2+-free medium and nicardipine inhibited, and Bay K 8644 potentiated the ET-1-induced contractions. ET-1 enhanced 45Ca2+ uptake in isolated arteries. Injections of ET-1 directly into the cerebral circulation decrease…

Pharmacological characterization and autoradiographic localization of histamine H2 receptors in human brain identified with [125I]iodoaminopotentidin…

1992

125I-Aminopotentidine (125I-APT), a reversible probe of high specific radioactivity and high affinity and selectivity for the H2 receptor, was used to characterize and localize this histamine receptor subtype in human brain samples obtained at autopsy. On membranes of human caudate nucleus, specific 125I-APT binding at equilibrium revealed a single component, with a dissociation constant of 0.3 nM and maximal capacity of about 100 fmol/mg of protein. At 0.2 nM, 125I-APT specific binding, as defined with tiotidine, an H2-receptor antagonist chemically unrelated to iodoaminopotentidine, represented 40-50% of the total. Specific 125I-APT binding was inhibited by a series of typical H2-receptor…

Broad-beam transmission data for new brachytherapy sources, Tm-170 and Yb-169

2005

The characteristics of the radionuclides (170)Tm and (169)Yb are highly interesting for their use as high dose-rate brachytherapy sources. The introduction of brachytherapy equipment containing these sources will lead to smaller required thicknesses of the materials used in radiation protection barriers compared with the use of conventional sources such as (192)Ir and (137)Cs. The purpose of this study is to determine the required thicknesses of protection material for the design of the protecting walls. Using the Monte Carlo method, transmission data were derived for broad-beam geometries through lead and concrete barriers, from which the first half value layer and tenth value layer are ob…

Percutaneous Stone Manipulation

1981

Percutaneous stone manipulation by direct ultrasound disintegration, extraction or chemolysis was done on 34 patients. A total of 15 patients presented with an operatively established nephrostomy, while percutaneous nephrostomy and subsequent dilation of the nephrostomy channel were done in 19. The rate of complete stone clearance was 19 of 20 stones after percutaneous nephrostomy and 8 of 16 stones in the group with an operatively established nephrostomy. The primary goal, to remove obstructing pelvic stones, was achieved in all cases. There were no untoward side effects, such as back pressure damage owing to flushing of the collecting system during ultrasound disintegration, or persistent…

Synthesis and in vitro evaluation of (S)-2-([11C]methoxy)-4-[3-methyl-1-(2-piperidine-1-yl-phenyl)-butyl-carbamoyl]-benzoic acid ([11C]methoxy-repagl…

2004

The 11 C-labeled sulfonylurea receptor 1 (SUR1) ligand (S)-2-(( 11 C)methoxy)-4-(3-methyl-1-(2-piperidine-1-yl-phenyl)- butyl-carbamoyl)-benzoic acid (( 11 C)methoxy-repaglinide) was synthesized in an overall radiochemical yield of 35% after 55 min with a radiochemical purity higher than 99%. This compound is considered for the noninvasive investigation of the SUR1 receptor status of pancreatic b-cells by positron emission tomography (PET) in the context of type 1 and type 2 diabetes. The specific activity was 40-70 GBq/lmol. In vitro testing of the nonradioactive methoxy-repaglinide was performed to characterize the affinity for binding to the human SUR1 isoform. Methoxy-repaglinide induce…

Analytical model for the long- distance tracer-transport in plants

2011

International audience; Recent investigations of long-distance transport in plants using non-invasive tracer techniques such as C radiolabeling monitored by positron emission tomography (PET) combined with magnetic resonance imaging (MRI) revealed the need of dedicated methods to allow a quantitative data analysis and comparison of such experiments. A mechanistic compartmental tracer transport model is presented, defined by a linear system of partial differential equations (PDEs). This model simplifies the complexity of axial transport and lateral exchanges in the transport pathways of plants (e.g. the phloem) by simulating transport and reversible exchange within three compartments using j…

The origin of heavy metals and radionuclides accumulated in the soil and biota samples collected in Svalbard, near Longyearbyen

2017

Heavy metals and radioactive compounds are potentially hazardous substances for plants, animals and humans in the Arctic. A good knowledge of the spatial variation of these substances in soil and primary producers, and their sources, is therefore essential. In the samples of lichen Thamnolia vermicularis, Salix polaris and Cassiope tetragona, and the soil samples collected in 2014 in Svalbard near Longyearbyen, the concentrations of the following heavy metals were determined: Mn, Ni, Cu, Zn, Cd, Pb and Hg, as well as the activity concentrations of the following: K-40, Cs-137, Pb-210, Pb-212, Bi-212, Bi-214, Pb-214, Ac-228, Th-231 and U-235 in the soil samples. The differences in the concent…

Preliminary results of studies on radioisotopes activity concentrations in vicinity of cement works

2012

W wielu miejscowościach znajdują się pozostałości po zakładach przemysłowych. Nawet jeśli taki teren został zrekultywowany, często obszary położone nieco dalej nie zostały przywrócone do pierwotnego stanu. Na takich terenach można spodziewać się istnienia podwyższonych stężeń różnych pierwiastków, w tym izotopów promieniotwórczych. Do badań pobrano próbki gleby na obszarze byłej cementowni „Piast”, znajdującej się w granicach miasta Opola oraz na obszarze pobliskich ogródków działkowych. W badanych próbkach stwierdzono obecność naturalnych izotopów promieniotwórczych oraz 137Cs. Największe aktywności wykazywały 40K oraz 137Cs. Aktywności naturalnych izotopów promieniotwórczych były znacznie…

IAEA Contribution to Nanosized Targeted Radiopharmaceuticals for Drug Delivery.

2022

The rapidly growing interest in the application of nanoscience in the future design of radiopharmaceuticals and the development of nanosized radiopharmaceuticals in the late 2000′s, resulted in the creation of a Coordinated Research Project (CRP) by the International Atomic Energy Agency (IAEA) in 2014. This CRP entitled ‘Nanosized delivery systems for radiopharmaceuticals’ involved a team of expert scientist from various member states. This team of scientists worked on a number of cutting-edge areas of nanoscience with a focus on developing well-defined, highly effective and site-specific delivery systems of radiopharmaceuticals. Specifically, focus areas of various teams of scientists com…

Graves’ disease

2017