ABSTRACT
This paper reports a novel nanosensor for tyrosine based on photoinduced electron-transfer (PET) between NaYF4:Yb, Tm upconversion nanoparticles (UCNPs) and melanin-like polymers. Melanin-like films were obtained from catalytic oxidation of tyrosine by tyrosinase, and deposited on the surface of UCNPs, and then quenched the fluorescence of UCNPs. Under the optimized conditions, the fluorescence quenching of UCNPs showed a good linear response to tyrosine concentration in the range of 0.8-100 µΜ with a detection limit of 1.1 µΜ. Meanwhile, it showed good sensitivity, stability and has been successfully applied to the detection of tyrosine in human serum.
Subject(s)
Blood Chemical Analysis/instrumentation , Fluorides/chemistry , Monophenol Monooxygenase/chemistry , Spectrometry, Fluorescence/instrumentation , Technetium/chemistry , Tyrosine/analysis , Yttrium/chemistry , Electron Transport/radiation effects , Enzymes, Immobilized/chemistry , Equipment Design , Equipment Failure Analysis , Fluorides/radiation effects , Humans , Light , Monophenol Monooxygenase/radiation effects , Reproducibility of Results , Sensitivity and Specificity , Technetium/radiation effects , Tyrosine/radiation effects , Yttrium/radiation effectsABSTRACT
Proton-induced nuclear reactions for generation of (99)Mo and (99m)Tc radionuclides were investigated using the stacked-foil activation technique on 99.05% enriched (100)Mo targets at energies up to Ep=21MeV. Excitation functions of the reactions (100)Mo(p,x)(99)Mo and (100)Mo(p,2n)(99m)Tc have been measured.
Subject(s)
Isotope Labeling/methods , Models, Chemical , Molybdenum/chemistry , Molybdenum/radiation effects , Technetium/chemistry , Technetium/radiation effects , Computer Simulation , Isotopes/chemistry , Isotopes/radiation effects , Materials Testing , Molybdenum/isolation & purification , Photons , Technetium/isolation & purificationABSTRACT
Nowadays, labelled polyclonal and monoclonal antibodies are widely used for immunoscintigraphic diagnosis of different diseases. Technetium-99m is often considered to be the label of choice for radioimmunodiagnosis for reasons of cost, availability and imaging properties, in spite of its relatively short physical half-life (6.01 h). The existing labelling methods may be classified into two types: direct approaches, in which disulphide bridges within are reduced to generate endogenous sulfhydryl groups able to efficiently bind technetium due to their strong chelating capacity and indirect methods, in which an exogenous chelator is covalently attached to the protein to serve as the binding site. All these procedures have their advantages and drawbacks. There is no consensus among the authors about which of the methods is the best. The employed approach depends on the particular situation. The aim of the present work is to show an update about the available procedures for 99mTc-labelling of antibodies and its fragments.
Subject(s)
Antibodies/chemistry , Immunoglobulin Fragments/chemistry , Isotope Labeling/methods , Technetium/chemistry , Avidin/chemistry , Biotinylation , Chelating Agents/pharmacology , Isotope Labeling/economics , Oxidation-Reduction , Pentetic Acid/analogs & derivatives , Pentetic Acid/pharmacology , Photochemistry , Reducing Agents/pharmacology , Sulfhydryl Compounds/pharmacology , Sulfhydryl Reagents/pharmacology , Technetium/economics , Technetium/radiation effects , Tin/chemistry , beta-Aminoethyl Isothiourea/pharmacologyABSTRACT
En este trabajo se analizó la frecuencia de aberraciones cromosómicas y de intercambios de cromátides hermanas (ICH) en los linfocitos de 10 niños expuestos a una dosis diagnóstica de Tc 99mm-DTPA para una gammagrafía cerebral. La frecuencia de aberraciones cromosómicas fue de 0.015 antes del estudio y de 0.010 después de la radiación. La frecuencia de ICH fue de 7.3 antes y 7.1 después de la gammagrafía. Estos resultados sugieren que este procedimiento diagnóstico que implica una sola dosis de radiaciones gamma no induce daño cromosómico
Subject(s)
Adolescent , Humans , Child, Preschool , Child , Cerebrum , Radiation Dosage , Lymphocytes , Technetium/adverse effects , Sister Chromatid Exchange/radiation effects , Technetium/radiation effectsABSTRACT
Technetium-99m radiopharmaceuticals are shown to be subject to autoradiation-induced decomposition, which results in increasing abundance of pertechnetate in the preparation. This autodecomposition is catalyzed by the presence of oxygen, although the removal of oxygen does not prevent its occurrence. The initial appearance of pretechnetate in the radiopharmaceutical is shown to be a function of the amount of radioactivity, the quantity of stannous ion used, and the ratio of Tc-99m to total technetium in the preparation.