RESUMO
(11)C-labeled carbamates can be obtained in a three-component coupling reaction of primary or secondary amines with CO(2) and (11)C-methylation reagents. [(11)C]Methyl-triflate mediated methylation of carbamino adducts provides the corresponding (11)C-labeled carbamate groups in excellent yields under mild conditions (temperatures = 40 degrees C, 2 min reaction time). The utility of the method has been demonstrated by a highly efficient radiosynthesis of [(11)C]GR103545.
RESUMO
The alpha-particle emitting radionuclides (223)Ra (t(1/2) = 11.4 d), (224)Ra (t(1/2) = 3.6 d), and (225)Ac(t(1/2) = 10.0 d) may have a broad application in targeted radiotherapy provided that they could be linked to vehicles with tumor affinity. The potential usefulness of liposomes as carriers was studied in the present work. Radium and actinium radionuclides could be loaded in good yields into sterically stabilized liposomes. Subsequent coating of the liposomes with a folate-F(ab')(2) construct yielded a product with affinity towards tumor cells expressing folate receptors. Radionuclide loaded liposomes showed excellent stability in serum in vitro.
Assuntos
Actínio/administração & dosagem , Actínio/farmacocinética , Lipossomos/química , Neoplasias Ovarianas/metabolismo , Radioimunoterapia/métodos , Rádio (Elemento)/administração & dosagem , Rádio (Elemento)/farmacocinética , Actínio/química , Partículas alfa/uso terapêutico , Proteínas de Transporte/metabolismo , Linhagem Celular Tumoral , Materiais Revestidos Biocompatíveis/síntese química , Portadores de Fármacos/síntese química , Portadores de Fármacos/química , Portadores de Fármacos/farmacocinética , Estabilidade de Medicamentos , Feminino , Receptores de Folato com Âncoras de GPI , Ácido Fólico/química , Ácido Fólico/farmacocinética , Humanos , Fragmentos Fab das Imunoglobulinas/imunologia , Lipossomos/síntese química , Lipossomos/farmacocinética , Taxa de Depuração Metabólica , Compostos Radiofarmacêuticos/administração & dosagem , Compostos Radiofarmacêuticos/síntese química , Compostos Radiofarmacêuticos/farmacocinética , Rádio (Elemento)/química , Receptores de Superfície Celular/metabolismo , EstereoisomerismoRESUMO
The aim of this study was to test the applicability of the guidance levels for patient doses cooperatively set by the radiation protection authorities in the five Nordic countries. The kerma-area product (KAP) for five conventional radiological examination types was obtained from several hospitals in each of the Nordic countries. The number of radiographic images and fluoroscopy time were also registered, and the mean values for each examination type and hospital were established based on a representative number of patients (40-100 kg). The results indicate that the situation is very similar in the five Nordic countries, even though some differences were identified. Most of the hospitals demonstrated lower doses than the proposed guidance levels for chest, probably explained by use of faster film/screen combinations during the past decade. An increased use of fluoroscopy for positioning was observed for radiographic examinations of lumbar spine and urography. Large variations in patient doses were found for barium enema depending on the use of fluorospot or 100-mm camera vs full-format film, the range in fluoroscopy times, dose rate, and field size. The guidance levels for lumbar spine (10 Gy x cm2), pelvis (4 Gy x cm2), urography (20 Gy x cm2), and barium enema (50 Gy x cm2) seem to reflect the present quality of X-ray equipment and examination techniques in the Nordic countries. The guidance levels for chest (1 Gy x cm2) should be lowered to 0.6 Gy x cm2.
Assuntos
Doses de Radiação , Radiografia , Sulfato de Bário , Meios de Contraste , Coleta de Dados , Enema , Fluoroscopia , Fidelidade a Diretrizes , Humanos , Intestinos/diagnóstico por imagem , Vértebras Lombares/diagnóstico por imagem , Pelve/diagnóstico por imagem , Guias de Prática Clínica como Assunto , Radiografia/normas , Radiografia Torácica , Países Escandinavos e Nórdicos , UrografiaRESUMO
Biotinyl-3-[211 At]astatoanilide ([211 At]AtBA) was prepared in more than 80% yield by destannylation. In vitro, [211 At]AtBA exhibited a high affinity for streptavidin, and was stable after incubation in human serum, cerebrospinal fluid and distilled water, whereas it was rapidly degraded in mouse serum. HPLC analysis showed that the main degradation pathway in mouse serum was the cleavage of [211 At]astatoaniline. In mice, [211 At]AtBA and its 125I-labeled analogue cleared rapidly from most tissues; however, there was some evidence for dehalogenation of both tracers.