National Repository of Grey Literature 47 records found  beginprevious38 - 47  jump to record: Search took 0.00 seconds. 
Interspecies comparison of plasma protein binding of two radiolabelled complexes
Smolová, Lenka ; Trejtnar, František (referee) ; Lázníček, Milan (advisor)
This paper engages in the newly prepared bifunctional chelate DTPA-oxn which has a potential use in radiolabelling biological macromolecules. The aim of the paper was to prepare a radiolabelled bifunctional chelate DTPA-oxn with a suitable radionuclide, the 90Y has been used. Binding of 90Y-DTPA-oxn to human, bovine, rabbit and rat plasma protein was determined. An equilibrium dialysis at 37řC was employed for the plasma protein binding determination. The received results received were compared with the results of plasma protein binding of a clinically routinely used bifunctional chelate DTPA radiolabelled with 99mTc (99mTc-DTPA). The results showed a low plasma protein binding of these radiolabelled chelates. Interspeices comparison demonstrated that the results obtained for human, bovine and rat plasma are comparable, whereas those obtained for rabbit plasma are higher. This brings a conclusion that the binding of 90Y-DTPA- oxn and 99mTc-DTPA to plasma protein is not a factor that can influence their biological behavior.
Study of Interspecies Differences in Plasma Protein Binding of New Radiopharmaceuticals
Smolová, Lenka ; Trejtnar, František (referee) ; Lázníček, Milan (advisor)
Study of interspecies differences in plasma protein binding of new radiopharmaceuticals Abstract This paper engages in a study on the plasma protein binding of chosen radiopharmaceuticals from the perspective of interspecies comparison. An equlibrium dialysis at 37řC was employed for the plasma protein binding determination and experiments were implemented on human, bovine, rabbit and rat plasma. Studies on the plasma protein binding were carried out with three new radiolabelled chelates and clinically routinely used bifunctional chelate DTPA radiolabelled with 99mTc (99mTc-DTPA). Binding was determined for the newly bifunctional chelate 90Y-DTPA-oxn and for the two potencional peptide based radiopharmaceuticals: 177Lu-DOTA-TATE a 177Lu-DOTA-MG-1. The results received were evaluated in light of interspecies comparison and compared with the results of the plasma protein binding of a clinically routinely used 99mTc-DTPA. Measuring data were analyzed using statistic data processing. The results of this analysis showed that statistically significant difference is for the complex 99mTc-DTPA between human and bovine and also between human and rabit plasma at the level of significance alfa 0,05. The results of all experiments carried out showed that the plasma protein binding is very low and therefore it is not a...
Study of Membrane Transport of Albumin in the Kidney in vitro
Suchan, Martin ; Trejtnar, František (advisor) ; Lázníček, Milan (referee)
Mgr. Martin Suchan 2010 Hradec Králové Doc. PharmDr. František Trejtnar, CSc. Katedra farmakologie a toxikologie Abstrakt Cíl: Práce byla zaměřena na studium transportu albuminu in vitro pomocí akumulačních buněčných studií a s využitím dvou typů albuminu - albuminu značeného techneciem- 99m a FITC-albuminu značeného fluorescenční sondou. Součástí práce bylo ověření optimální přípravy a hodnocení kvality 99m Tc-albuminu. Cílem bylo porovnat akumulaci obou typů albuminu v ledvinných buňkách, zjistit vliv vybraných faktorů na akumulaci albuminu, stanovit typ mechanismu transmembránového transportu albuminu a zpracovat získané výsledky do formy odborného vědeckého sdělení. Metody: Ke značení albuminu techneciem-99 bylo použito optimalizovaného postupu za použití nízkého pH, vysoké koncentrace albuminu a optimální koncentrace cínatých iontů. Radiochemická čistota 99m Tc-albuminu byla ověřována chromatografií na papíře. Jako buněčné in vitro modely byly použity izolované nativní ledvinné buňky potkana a standardní linie ledvinných tubulárních buněk prasete LLC-PK1. V akumulačních studiích byl sledován uptake albuminu v závislosti na teplotě, čase, složení inkubační směsi, přítomnosti inhibitoru transportu a byl hodnocen vliv experimentálního modelu. U LLC-PK1 buněk byl též testován vliv stáří buněk na míru...
Study of plasma protein binding of two bifunctional chelates labelled with In-111
Drymlová, Petra ; Lázníček, Milan (advisor) ; Trejtnar, František (referee)
Summary: Distribution of many drugs in an organism is significantly influenced by their binding to plasma proteins. Determination of the extent of plasma binding for a concrete drug is necessary for prediction of its pharmacokinetics after administration to the organism. The aim of this thesis was to determine binding of a new bifunctional chelating agent DTPA-oxn labelled by 111 In to the plasma proteins of human and tree animal species and to compare these results with the plasma protein binding of routinely used radiopharmaceutical 111 In-DTPA. For measurement, a method of equilibrium dialysis at 37řC was used. The results show, that binding of 111 In-DTPA-oxn to the proteins of human, bovine, rabbit and rat plasma is similarly very low as at the compared chelate 111 In-DTPA and impossible to determine by equilibrium dialysis and pharmacokinetically unimportant. Radiochemical purity was also determined for both complexes by the method of thin layer chromatography ITLC-SG. Measured value was higher than 98% for each compound.
Preparation of radiolabeled albumin
Suchan, Martin ; Trejtnar, František (advisor) ; Lázníček, Milan (referee)
Objectives: This senior thesis was aimed at determining a method of albumin labelling with a particular radionuclide - technetium 99m Tc. Our task was to review the various possible methods needed for working out a procedure for albumin labelling with the mentioned radioisotope and also to test the behavior of labelled albumin in vitro in experiments with newly-isolated rat kidney cells. The next objectives of this work were to analyze the performed experiments, compare the results with other known procedures of albumin labelling with technetium 99m Tc and cast the results in the form of a scientific statement. Methods: A low pH and high concentration of albumin were useful for the albumin labelling experiments. A solution of SnCl2.2H2O was used for the reduction of pertechnetate. Purification of labelled albumin was performed by gel chromatography with a Sephadex G-50. The locations of albumin peaks in the chromatographic fractions were determined by the bicinchonic method. The location of pertechnetate was found by investigating the chromatographic spectrum of pertechnetate. Investigation of the elution spectrum was used to check for proper labelling. The radiochemical purity of labelled albumin was verified by paper chromatography and subsequent detection. Newly- labelled albumin was used in the...
Study of Transport Mechanisms of Receptor-Specific Radiopharmaceuticals in the Kidney Cells.
Cihlo, Jan ; Lázníček, Milan (advisor) ; Šimůnek, Tomáš (referee) ; Komárek, Pavel (referee)
Renal accumulation of radiolabelled receptor specific substances can represent clinical problems for diagnosis and therapy of some typical malignancies due to radionephrotoxicity of these substances. The aim of this work was to design a suitable in vitro model for evaluating cumulative disposals of studied radiopharmaceuticals in the kidney and for finding possible mechanisms reducing the reabsorption of these substances by renal tubular cells. The suggested model designed for this purpose provides another opportunity for evaluation of their radionephrotoxical potential. The aforementioned in vitro method was standardised and used for the study of transport mechanism of some representatives of radiolabelled somatostatin analogues (111In/125I/90Y/177Lu-DOTA-Tyr3-octreotate, 111In/90Y/177Lu-DOTA-1-Nal3-octreotide), antibodies (111In/90Y/99mTc-AntiCD66) and albumin (FITC-albumin, 99mTc-albumin). All studied radioactive substances were radiolabelled with good practice and analyzed using HPLC and/or ITLC-SG methods. The radiolabelling technique of all studied specifically acting substances (radiolabelled peptides and antibodies) and also any concrete radionuclide showed no significant influence over the internalization into the renal OK cells. The difference of the internalized amount of FITC-albumin and...
Study of interspecies differences in plasma protein binding of 18F-labeled radiopharmaceuticals
Nováková, Dana ; Lázníček, Milan (advisor) ; Bárta, Pavel (referee)
Charles University in Prague, Faculty of Pharmacy in Hradec Králové Department of Pharmacology and Toxicology Candidate: Mgr. Dana Nováková Consultant: Prof. PharmDr. Ing. Milan Lázníček, CSc. Title of Thesis: Study of interspecies differences in plasma protein binding of 18 F-labeled radiopharmaceuticals In this thesis, the binding ability of three radiopharmaceuticals containing radionuclide 18 F to the plasma proteins was examined in bovine, pig, human and rat plasma, and the interspecies comparison was performed. Examined radiopharmaceuticals included 18 F-FDG, 18 F-fluorocholine and 18 F-thymidine. The two main methods used are equilibrium dialysis and ultrafiltration. These methods are based on separation of free ligand from the linked component. During the separation, semi-permeable membrane and special filters (AMICON and VIVASPIN) were used for equilibrium dialysis and ultrafiltration, respectively. Free fraction of drugs is considered to be an important parameter for the availability of the drug distribution into the tissues and cells, interaction with receptors, excretion and metabolism. All experiments were carried out at the physiological temperature of 37řC. Obtained results indicate low plasma protein binding of the three radiopharmaceuticals in all studied species, which suggests...

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1 Lázniček, Matěj
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