Search Results
Summary
Crotoxin (Crtx) is the main toxin of South American rattlesnake (Crotalus durissus terrificus) venom. Research on antitumoral drugs has demonstrated the potential use of Crtx as tumour reducing agent. Tissue distribution studies are very important for clinical use and 99mTc-labeling is a very convenient method for studies related to biodistribution. The aim of the present study was to label Crtx with 99mTc keeping its biological activity for use in biodistribution and binding studies. High labeling yield was obtained using stannous chloride and sodium borohydride. Results demonstrated that biological activity of 99mTc-Crtx was preserved and confirmed kidneys as the target organ. Biological activities of unlabeled and 99mTc-labeled Crtx were evaluated after labeling. 99mTc-Crtx can be a useful tool for imaging and binding studies.
Abstract
The adsorption behaviour of99Mo in the form of molybdate and of99mTc in the form of pertechnetate on hydrated titanium dioxide was investigated at different molarities of hydrochloric acid. The adsorption capacity of molybdate on hydrated TiO2 is higher than on Al2O3. A99mTc-generator is suggested. This generator is based on the adsorption of (99Mo) molybdate on hydrated TiO2, at acidities of 0.05–0.1M. HCl.99mTc is eluted with 0.9% NaCl. Radionuclidic, radiochemical and chemical purities of the eluates were checked. This generator seems to have a great potential as compared to the traditional alumina generators.
Abstract
Dialysis and precipitation methods have been used to study the binding affinity of selected technetium-99m phosphorus radiopharmaceuticals to human serum proteins. The binding affinities of three different99mTc bone imaging agents were found to be inversely related to their respective clearance rates from blood in vivo. The binding order showed99mTcPPi>99mTcHEDP>99mTcMDP. The99mTc phosphorus radiopharmaceuticals were bound primarily to alpha globulins. The results suggest that the binding of99mTc phosphorus radiopharmaceuticals to human serum proteins in blood is largely determined by their affinities to the alpha globulins.
Summary
Cyanocobalamin (CNCbl), a kind of vitamin B12 (cobalamin, Cbl), which has a special binding capability to rapid dividing cells and proliferating tissue, especially tumors, has been modified and labeled by 99mTc. The optimal labeling condition was determined, and the biodistribution of 99mTc-DTPA-b-CNCbl both in normal mice and TA2 mice bearing MA891 mammary tumors were studied. 99mTc-DTPA-b-CNCbl showed low uptake and rapid clearance in nontarget tissues, and renal excretion. About 40% of uptake at 1 hour remained in the tumor at 12 hours p.i. The satisfying ratio of T/NT was acquired at 6 hours p.i.
Abstract
Prevention of the tailing of99mTc-complexes in paper and ITLC chromatographic systems through understanding of the chemistry of this artefact is the aim of the study. Use of eluents with the same composition as the labeling medium of the complex, except tin, actually reduces the tailing. The effects of temperature and pH of the eluent on the phenomenon imply that the stability of the complex is its main determinant. Weakening of the complex by dilution in the normal saline eluent is followed by an interaction of the99mTc with the supporting medium or by a modification of the nature of99mTc (colloid formation). Unfortunately, if complexing eluents prevent the tailing and have no influence on the pertechnetate impurity, they are not suitable for routine quality control since reduced99mTc partially migrates in these systems.
Abstract
The half time for the99mTc labelling of red blood cells which have been pretreated with stannous pyrophosphate is determined in an in vitro system and shown to be approximately 5 minutes.
Abstract
The modified method of99mTc-HIG peparation and quality control in our laboratory are reported. The results of phamacology and preliminary clinical evaluation show that the new agent is nearly ideal for localization of infectious/inflammatory lesions.
Abstract
This study compares the biological behavior of the99mTc-cysteine complex with131I-hippuran (131I-OIH). The potential role of the99mTc-cysteine complex as a renal imaging agent has also been evaluated. In addition the biological characteristics, i.e., biodistribution, blood clearance, excretory mechanism and the renal excretion pattern in the presence and absence of the tubular transport inhibitor (2,4-dinitrophenol, probenecid) has been examined. The experimental results reveal that kidneys are the target organ. The blood clearance of these radiopharmaceuticals is rapid, approximately 84% of the injected activity is excreted from the kidneys at 1 hour postinjection. Moreover, the renal inhibitor obviously depresses the excretory rate of the99mTc-cysteine and131I-OIH, suggesting that such agents are excreted by renal tubular secretion. Results presented demonstrate that the99mTc-cysteine is a remarkable renal dynamic imaging agent which is highly promising as a new renal imaging radiopharmacentical.
Abstract
Combined extraction of99Mo and its daughter-product99mTc enables a rapid determination of molybdenum in biological samples by neutron activation analysis. A procedure and its application to standard kale powder and standard animal blood are reported.
Summary
The aim of this study was to label exorphin C with 99mTc and to examine its usefulness as opioid receptor binding radiopharmaceutical in Albino Wistar rats. Exorphin C, which is a peptide with 5 aminoacids, was labeled with 99mTc using glucoheptonate (GH) as a bifunctional chelating agent. Labeling efficiency was higher than 98%. The compound was stable for at least 5 hours at room temperature. Mammary tumor bearing Albino Wistar rats were imaged using gamma-camera. Biodistribution studies were also performed. Results demonstrated that 99mTc-glucoheptonate-exorphin C (99mTc-GE) analogs may be useful as a new class of receptor-binding peptides for the diagnosis and therapy of some cancer diseases related with opioid receptor-expressing tissues.
