Browsing by All Authors "Duman, Yusuf"

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    Clinical evaluation of GLY-GLY-Alanine and same group peptides labeled with 99mTc
    (Turkish Atomic Energy Authority, 2000-10) Taner, Memduh Sami; Özdemir, Durmuş; Duman, Yusuf; 99mTc; Bölüm Yok
    In this study, seven different (six of them with -N H and one of them with -NHSH side chain) peptides (Gly-l-Hystidine, Gly-l-Methionine, Gly-l-Tyrosine, Gly-Gly-l-Alanine, Gly-l-leucine amide, Gly-l-Glutamic acid, Gly-l-Gly-amide) were selected. For the positive control, tetraglycin (Gly-Gly-Gly-Gly) was chosen and for each of them, " mTc labeling studies have been performed using both direct and ligand exchange methods. Among these peptides, two of them (Gly-Gly-l-Alanine (GGA) and Gly-l-leucyl amide(GLA)) were labeled with the yields that were close to the USP acceptance criterions. Quality control has been performed by reverse phase HPLC analysis method with the use of a Beckman-Gold Radio-HPLC system. Latter on, radiopharmaceutical distribution and organ uptake characteristics of these peptides (" mTc-GGA and 99mTc-GLA) on rabbits were studied by using gamma camera imaging technique. Also, animal bio-distribution with GGA and inflammation imaging studies with GLA on rat models with sterile inflammation have been performed. Results indicated that in direct radio-labeling method developed for the small molecule peptides, labeling yields and retention times for " mTcGGA and " mTc-GLA radio-complexes were % 75.09 at 12 minute and % 74.20 at 17.5 minutes, respectively in reverse phase Radio-HPLC analysis. For the rest of the five peptides, direct and ligand exchange labeling methods were unsuccessful to produce a radio-labeled peptide that has an acceptable yield in terms of the radiopharmaceutical quality. Gamma camera imaging studies have indicated that both of the peptides ( " mTc-GGA and " mTcGLA) have demonstrated remarkable rapid blood clearance and dynamic discharge through kidneys. It is possible to say that based on the initial images and renogram data, dynamic kidney imaging can be obtained right after 30 minutes of the application and static kidney scintigrams can be taken by performing late imaging with " mTc-GGA radio-peptide complex. On the other hand, " mTc-GLA complex may have a potential use especially for very clear dynamic kidney and infection imaging studies. In bio-distribution study on rabbits, in terms of radio-peptide retention, the most important organ and body fluid samples were taken and then counted (first with collimated and then with non-collimated gamma camera counting system) with TENELLEC well type detector system. When compared to the other body organs, it was observed that kidneys showed the most active retention and the most of the applied radiopeptide were thrown out through urine. Also, In the infection imaging studies on mouse models with colitis using the same radio-labeled peptides, 99mTc-GLA proved to be more appropriate as indicated by the scintigrams.
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    Is it possible to do radiopharmaceutical quality control with a gamma camera
    (Turkish Atomic Energy Authority, 2000-10) Taner, Memduh S.; Özdemir, Durmuş; Köseoğlu, Kamil; Duman, Yusuf; Bölüm Yok
    All of the imaging studies in nuclear medicine start with a suitable radiopharmaceutical preparation step. In radiopharmaceutical synthesis, an organic or biochemical molecule is combined with a radioactive element to form a complex. This process is known as radiolabeling (1). In a radiopharmaceutical labeling study, it is important to realize that whether or not the radiolabeled chemical complex is in the expected radiochemical form has a vital role for all the nuclear medicine imaging processes. The common method of radiopharmaceutical quality control is the chromatographic analysis such as PC, TLC, and HPLC. In nuclear medicine practice, application of these methods is called radiopharmaceutical quality control(2). The agrement of results obtained from such chromatographic analysis methods with the criterions given in United States Pharmacopea (USP) means the regulatory permission of the use of that radiopharmaceutical in proposed applications^). In this study separation of several labeled radiopharmaceuticals were demonstrated by using standard support materials and solvents. After dying the chromatographic support material, a gamma camera (TOSHIBA GCA-602A) was used to do radiation counting and static imaging for 2 minutes. These images, then, was divided into rectangular pieces (5 x 25 in pixel) and Region of Interest (ROI) process was applied to them. The percent labeling yields were calculated by plotting total count for each area against the number of area. It was also demonstrated that the Rf values obtained from gamma camera studies were in agreement with the Rf values obtained with classical methods.