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Ozkan M, Muftuler FZB, Kilcar AY, Medine EI, Unak P. Isolation of hydroxytyrosol from olive leaves extract, radioiodination and investigation of bioaffinity using in vivo/in vitro methods. RADIOCHIM ACTA 2013. [DOI: 10.1524/ract.2013.2068] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Summary
It is known that medicinal plants like olive have biological activities due to their flavonoid content such as olueropein, tyrosol, hydroxytyrosol etc. In current study, hydroxytrosol (HT) which is one of the major phenolic compounds in olive, olive leaves and olive oil, was isolated after methanol extraction and purification of olive leaves which are grown in the northern Anatolia region of Turkey. The isolated HT was radiolabeled with 131I (131I-HT) and the bioaffinity of this radiolabeled component of olive leaves extract was investigated by using in vivo/in vitro methods. It was found that HT could be radiolabeled with 131I in yields of 95.6±4.4% (n = 8), and in vivo studies showed that 131I-HT is taken up by urinary bladder, stomach, small intestine, large intestine, breast and prostate. Significant incorporation of activity was observed in cell lines via in vitro studies.
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Affiliation(s)
- M. Ozkan
- Ege University, Department of Nuclear Applications, Institute of Nuclear Sciences, 35100 Bornova, Izmir, Turkey
| | - F. Z. Biber Muftuler
- Ege University, Department of Nuclear Applications, Institute of Nuclear Sciences, 35100 Bornova, Izmir, Turkey
| | - A. Yurt Kilcar
- Ege University, Department of Nuclear Applications, Institute of Nuclear Sciences, 35100 Bornova, Izmir, Turkey
| | - E. I. Medine
- Ege University, Department of Nuclear Applications, Institute of Nuclear Sciences, 35100 Bornova, Izmir, Turkey
| | - P. Unak
- Ege University, Department of Nuclear Applications, Institute of Nuclear Sciences, 35100 Bornova, Izmir, Turkey
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Muftuler FZB, Unak P, Yolcular S, Kilcar AY, Ichedef C, Enginar H, Sakarya S. Synthesis, radiolabeling and In Vivo tissue distribution of an anti-oestrogen glucuronide compound, (99m)Tc-TOR-G. Anticancer Res 2010; 30:1243-1249. [PMID: 20530435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Toremifene (TOR) has been used as an anti-oestrogen drug for the treatment and prevention of human breast cancer. The aim of this study was the addition of the hydrophilic groups diethylenetriamine pentaacetic acid (DTPA) and glucuronic acid to the starting substance TOR and to label it with technetium-99m ((99m)Tc) radionuclide and to investigate radiopharmaceutical potential of the new compound. The synthesis reactions are completed in four steps, including enzymatic reaction, with the following substeps; preparation of microsomal fraction from Hutu 80 cell line and subsequent purification of UDP-glucuronyl transferase (UDPGT), estimation of protein quantity in microsomal samples and glucuronidation reaction. The results indicate that (99m)Tc-TOR-G may be proposed as a new anti-oestrogen glucuronide imaging agent for ovarian tumours.
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Affiliation(s)
- F Z Biber Muftuler
- Department of Nuclear Applications, Institute of Nuclear Sciences, Ege University, Izmir, Turkey.
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Decristoforo C, Elsinga P, Faivre-Chauvet A, Farstad B, Meyer G, Mikolajczak R, Penuelas I, Unak P, Westera G. The specific case of radiopharmaceuticals and GMP—activities of the Radiopharmacy Committee. Eur J Nucl Med Mol Imaging 2008; 35:1400-1. [DOI: 10.1007/s00259-008-0827-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/15/2008] [Indexed: 11/28/2022]
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4
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Yurt Lambrecht F, Yilmaz O, Unak P, Seyitoglu B, Durkan K, Baskan H. Evaluation of 99mTc-Cefuroxime axetil for imaging of inflammation. J Radioanal Nucl Chem 2008. [DOI: 10.1007/s10967-007-7111-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Muftuler FZB, Unak P, Teksoz S, Acar C, Yolcular S, Yürekli Y. 131I labeling of tamoxifen and biodistribution studies in rats. Appl Radiat Isot 2008; 66:178-87. [PMID: 17888670 DOI: 10.1016/j.apradiso.2007.08.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Revised: 06/11/2007] [Accepted: 08/06/2007] [Indexed: 11/15/2022]
Abstract
Tamoxifen [TAM ([Z]-2-[4-(1,2-diphenyl-1-di-butenyl)-phenoxy]-N,N-dimethylethanamine)] has been used as an antiestrogen drug for treatment and prevention of human breast cancer. Tamoxifen was labeled with 131I using iodogen as an oxidizing agent. Mass spectroscopy of the cold standard showed that the labeling occurs in ortho position to the phenyl ether position of TAM as expected. Quality control, radiochemical yield and stability were established using the radioelectrophoresis method. The radiolabeled compound maintained its stability throughout working period of 24 h. Scintigraphic imaging was performed and tissue distribution was determined in Albino Wistar rats. According to biodistribution and imaging experiments the radiolabeled compound presented estrogen receptor (ER) specificity and it was uptaken by endometrium as well as breast tissue.
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Affiliation(s)
- F Z Biber Muftuler
- Department of Nuclear Applications, Institute of Nuclear Sciences, Ege University, Bornova-Izmir, Turkey.
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Unak P, Teksoz S, Biber Muftuler FZ, Medine EI, Acar C, Yurekli Y. 99mTc-glucoheptonate-guanine: Synthesis, biodistribution and imaging in animals. J Radioanal Nucl Chem 2007. [DOI: 10.1007/s10967-007-6934-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Ertay T, Unak P, Biber FZ, Tasci C, Zihnioğlu F, Durak H. Scintigraphic imaging with a peptide glucuronide in rabbits: 99mTc- exorphin C glucuronide. Appl Radiat Isot 2007; 65:170-5. [PMID: 17110118 DOI: 10.1016/j.apradiso.2006.03.017] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2005] [Revised: 01/13/2006] [Accepted: 03/27/2006] [Indexed: 10/23/2022]
Abstract
A peptide glucuronide (Exorphin C glucuronide) was labeled with 99mTc using glucoheptonate (GH) as a bifunctional chelating agent. Scintigraphic imaging was performed in male Albino rabbits. Exorphin C glucuronide showed rapid and efficient labeling with 99mTc using glucoheptonate as a bifunctional chelate. Results demonstrated that 99mTc-GEG may be a useful new type of glucuronide derivative of peptides for diagnosis of some cancer diseases.
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Affiliation(s)
- T Ertay
- Dokuz Eylül University, Medical School, Department of Nuclear Medicine, Inciralti, Turkey.
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Biber FZ, Unak P, Ertay T, Medine EI, Zihnioglu F, Tasci C, Durak H. Synthesis of an estradiol glucuronide derivative and investigation of its radiopharmaceutical potential. Appl Radiat Isot 2006; 64:778-88. [PMID: 16531048 DOI: 10.1016/j.apradiso.2006.02.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2004] [Revised: 01/31/2006] [Accepted: 02/01/2006] [Indexed: 10/24/2022]
Abstract
The aim of the current study was to synthesize a derivative of estradiol glucuronide, which is able to be labeled with 99mTc and to investigate its radiopharmaceutical potential using imaging and biodistribution studies. An estrogen derivative, beta-estradiol (1,3,5,[10]-estratriene-3,17beta-diol) attached to diethylenetriamine pentaacetic acid (DTPA) was synthesized in six steps. At the end of these steps a compound of estradiol and DTPA derivative called deoxy demethyl homoestradiolyl diethylenetriamine pentaacetic acid (ESTDTPA) was synthesized. Afterwards, this compound was reacted with UDP-glucuronyl transferase (UDPGT). Following the glucuronidation reaction, the product called deoxy demethyl homoestradiolyl diethylenetriamine pentaaceticacid-glucuronide (ESTDTPAG) was obtained. Synthesized products were purified using high performance liquid chromatography (HPLC). The identification of the purified products and impurities were also established using HPLC. Synthesized compound was labeled with 99mTc. Thin layer radio chromatography (TLRC) technique was used to determine their radiochemical yields and stabilities. Labeling yield was over 96%. The biodistribution studies were performed on female Albino Wistar rats. The activity per gram tissue was calculated and time-activity curves were plotted. The target organs (tumor, as well as uterus, ovaries, adrenals and other ER containing tissues) retain the estradiol derivative longer than nontarget organs, but even these lost most of their activity within a few hours. In addition, the imaging studies were performed on normal and tumor bearing female Albino Wistar rats using Camstar XR/T gamma camera. In gamma-scintigraphic imaging studies with 99mTc-ESTDTPAG the breast tumors could be well visualized up to 24 h.
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Affiliation(s)
- F Z Biber
- Department of Nuclear Applications, Institute of Nuclear Sciences, Ege University, 35100 Bornova Izmir, Turkey.
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Biber FZ, Unak P, Enginar H, Ertay T, Medine EI, Tasci C, Durak H. Synthesis of DTPA-attached estradiol derivative and determination of its radiopharmaceutical potential. J Radioanal Nucl Chem 2005. [DOI: 10.1007/s10967-005-0930-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Ertay T, Unak P, Tasci C, Zihnioğlu F, Durak H. Scintigraphic imaging with 99mTc- exorphin C in rabbits. Appl Radiat Isot 2005; 62:883-8. [PMID: 15799865 DOI: 10.1016/j.apradiso.2004.10.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2004] [Revised: 09/10/2004] [Accepted: 10/19/2004] [Indexed: 10/25/2022]
Abstract
Exorphin C is a peptide with five amino acids [(Tyr-Pro-Ile-Ser-Leu) Trifluoroacetate salt] (Sigma) that has an affinity to opioid receptor-expressing tissues and tumors. Exorphin-C was labeled with 99mTc using glucoheptonate (GH) as bifunctional chelating agent. Then, we investigated its radiopharmaceutical potential as opioid receptor-expressing tissue on rabbits. Quality controls were performed by ITLC, paper electrophoresis and HPLC. Labeling efficiency was higher than 98%. The compound was stable for at least 5 h at room temperature. Scintigraphic imaging with 99mTc-GH-exorphin C (99mTc-GE) was performed on male Albino rabbits. Static images were obtained from anterior projection using a Camstar XR/T gamma camera at several time intervals. Although a significant amount of activity was seen in the brain, less activity was seen on receptor saturation studies at 30 min. Slight hepatobiliary excretion was seen, though the main excretion route was renal. After saturating, the receptor hepatobiliary excretion was not seen; the only excretion route was renal.
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Affiliation(s)
- T Ertay
- Department of Nuclear Medicine, Medical School, Dokuz Eylül University, Inciralti, Turkey.
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Enginar H, Unak P, Yurt Lambrecht F, Biber FZ. Synthesis of a99mTc labeled estrogen-derivative and the determination of its radiopharmaceutical potential on rats. J Radioanal Nucl Chem 2004. [DOI: 10.1023/b:jrnc.0000027107.43043.37] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Abstract
lodization of consumed salts is mandatory in many countries fighting against to iodine deficiency. In salts iodine stability is affected by storage conditions. In this study, stabilization of iodine in salt has been determined by using Isotope Dilution Analysis. Heating, heating with oxidizing agent, incubation by time were the parameters which have been determined. Iodine loss was 41.16% by heating at 200 degrees C up to 24 hours. When the iodized salt heated with oxidized agent iodine loss rose up to 58.46% in 24 hours. Iodine loss mechanism seems similar in both cases. However iodine loss is greater in the presence of H202. After the salt was stored at room temperature with a relative humidity of 30%-45% and in sealed paper bags for three years, 58.5% of iodine content lost in approximately 3.5 years.
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Affiliation(s)
- F Z Biber
- Ege University, Institute of Nuclear Sciences, Bornova Izmir, Department of Nuclear Applications, Turkey
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Ertay T, Unak P, Bekis R, Yurt F, Biber FZ, Durak H. New radiolabeled CCK-8 analogues [Tc-99m-GH-CCK-8 and Tc-99m-DTPA-CCK-8]: preparation and biodistribution studies in rats and rabbits. Nucl Med Biol 2001; 28:667-78. [PMID: 11518648 DOI: 10.1016/s0969-8051(01)00196-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The aim of this study is to label CCK-8 with Tc-99m and to investigate its radiopharmaceutical potential. CCK-8 was labeled with Tc-99m using GH and DTPA as bifunctional chelating agents. Labeling efficiency was higher than 99%. Complex was stable more than 5 hours at room temperature. 37 MBq Tc-99m-GH-CCK-8 or Tc-99m-DTPA-CCK-8 was administered intravenously to rabbits for biodistribution experiments. Dynamic and static images were obtained from anterior projection using a Camstar XC/T gamma camera. For quantitative evaluation, regions of interest were drawn on organs and time-activity curves were generated. The highest accumulation occurred in brain within 10 and 30 minutes after injection. Renal and hepatobiliary excretion were observed. Brain distribution studies in rats showed the highest activity was in hypothalamus. Results demonstrated that Tc-99m-GH-CCK-8 and Tc-99m-DTPA-CCK-8 analogs may be a useful new class of receptor-binding peptides for diagnosis and therapy of brain diseases related with CCK-B receptor-expressing tumors.
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Affiliation(s)
- T Ertay
- Dokuz Eylül University, Medical School, Dept. of Nuclear Medicine, Inciralti, Izmir, Turkey
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Abstract
The aim of this study was to demonstrate the accumulation of 131I-labeled ornidazole (131I-ORN) in experimental abscesses. 131I-ORN was prepared by electrophilic radioiodination of ORN, using radioiodide in the presence of Iodogen. An in vivo inflammation model was prepared by intramuscular injection of turpentine into the thigh of rabbits. Four days later 131I-ORN was intravenously administered to rabbits. Serial scintigrams were performed at different periods, using a Sophy DX Gamma Camera. 131I-ORN was visualized at 10 min after injection. 131I-ORN was also administered intraperitoneally to rats with turpentine-induced inflammation, for quantitative biodistribution studies. Counts of selected tissues were taken by a NaI(Tl) scintillation detector (gamma counter) after rats were decapitated. The target-to-non-target muscle ratios were 2.5, 2.6, 2.9 and 1.9 at 1, 3, 5 and 24 h, respectively.
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Affiliation(s)
- M Asikoglu
- Faculty of Pharmacy, Department of Radiopharmacy, Ege University, Bornova, Izmir, Turkey.
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Yurt F, Unak P, Ozkilic H, Uluc F, Bagci S, Tuglular I. Labeling of zopiclone with iodine-131. Nucl Med Biol 1999; 26:827-31. [PMID: 10628564 DOI: 10.1016/s0969-8051(99)00046-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Zopiclone (ZPC) was labeled with 131I by using the halogen exchange method. Temperature and reaction time effects to labeling yields were studied. Infrared, nuclear magnetic resonance, and gas chromatography-mass spectroscopy spectra were undertaken to identify chemical structure. High performance liquid chromatography (HPLC) was performed to determine purity of cold zopiclone. Biodistribution studies were performed on rabbits and rats. 131IZPC was administered intravenously to rabbits. Static images were taken by a Sophy DX Gamma Camera. 131IZPC was also administered intraperitoneally to rats. Activities were counted in a NaI(Tl) scintillation detector for several organs (liver, brain, spleen, lung, blood, fat) after rats were decapitated on different times. Biodistribution profiles were obtained depending on the time.
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Affiliation(s)
- F Yurt
- Institute of Nuclear Science, Ege University, Bornova, Izmir, Turkey
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Abstract
Urinary iodide and iodine in drinking water were determined in 318 healthy children aged 0 to 18 yr living in Izmir and environmental rural and urban areas in the western part of Turkey. The method is based on substochiometric isotope dilution analysis. Iodide was precipitated by substoichiometric amounts of AgNO3. Iodide-131 was used as a tracer. Electrophoresis was performed to separate Ag131I from excess 131I-. The Ag131I zone was cut off the electrophoresis paper and counted with a NaI(Tl) scintillation counter. Count rates were plotted versus added KI concentrations. The unknown iodide amount was found by using these linear plots. Iodide concentration ranges were within 1.8-100.45 micrograms/L in the analyzed drinking water samples. The mean value was 44.14 +/- 17.33 micrograms/L and the median was 58.08 micrograms/L. Urinary iodide concentration ranges were 0.22-142.22 micrograms/L. The median of the distribution was 37.71 micrograms/L and the mean was 40.30 +/- 24.05 micrograms/L. The results show that the examined area suffers moderate iodine deficiency.
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Affiliation(s)
- P Unak
- Department of Nuclear Applications, Ege University, Bornova Izmir, Turkey
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Abstract
Complex forming conditions of Penicillamine di sulfide with 99mTc have been specified. Labeling of penicillamine di sulfide with 99mTc by direct reduction with SnCl2 did not give favorable good results while the 99mTc complex of penicillamine can be easily obtained. Ligand exchange reaction with 99mTc-gluconate was attempted and a 95% labeling efficiency was obtained. Radiopharmaceutical potential of 99mTc-PADS (99mTc-Penicillamine di sulfide) has been investigated with a gamma camera in rabbits and the complex was found to be uptaken mostly by the liver and kidneys.
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Affiliation(s)
- P Unak
- Institute of Nuclear Sciences, Ege University, Bornova, Izmir, Turkey
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Abstract
Some types of cancer cells have high levels of beta-glucuronidase activity. This enzyme is able to deglucuronidate a variety of glucuronide derivatives on the cell membrane. Either O- or N-glucuronides can be selectively incorporated into the cancer cells. If the aglycone is cytotoxic, the glucuronide can potentially be used as a selective anti-cancer drug in cancers with high levels of beta-glucuronidase activity. Nevertheless, in vitro studies carried out by various investigators have shown that the cytotoxicities of several glucuronides in cancer cells are not sufficiently high for their use as effective anti-cancer drugs. For this reason, we have synthesized glucuronide compounds radiolabelled with iodine-125 combining the radiotoxicity of this Auger electron emitter with the chemotoxicity of the aglycone portion of the glucuronide.
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Affiliation(s)
- T Unak
- Faculty of Science, Department of Chemistry, Ege University, Bornova, Izmir, Turkey
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Abstract
8-Hydroxy-quinolyl-glucuronide (8-HOQ-Glu) can be deglucuronidated by the beta-glucoronidase enzyme, which has an activity that is considerably high in certain kinds of cancer cell. Owing to this enzyme activity, 8-HOQ-Glu can be considered as a potential anti-cancer drug. The combination of the radiotoxicity known of 125I nuclide with the cytotoxicity of 8-hydroxy-quinoline (8-HOQ) and particularly the selective carrying of 125I into the cancer cells is the principal aim of this study. As a first step, the metabolic 8-HOQ-Glu was extracted from the urine of rabbits treated with 8-HOQ directly radioiodinated using the iodogen method. The results showed that the radioiodination was successfully realized, and its yield was found to be about 90-95%.
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Affiliation(s)
- T Unak
- Department of Chemistry, Faculty of Science, Ege University, Izmir, Turkey
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Abstract
The compound known as "synkavit" is a diphosphate derivative of vitamin K3 (menadion), which is capable of being selectively accumulated in certain tumour cells, and covalently bonded to DNA producing considerable DNA damage. On the other hand, iodine-125 nuclide incorporated into the nucleus of living cells causes extreme radiotoxic effects. Consequently, synkavit can be used as a specific carrier of iodine-125 into the nucleus of tumour cells. Thus, its iodo-derivatives have become interesting agents on the potential application of iodine-125 in cancer therapy. 6-Iodo-synkavit is a unique iodo-derivative described in the literature. In addition, its synthesis and radioiodination is still problematic, and consequently the results obtained using 6-iodo-synkavit labelled with iodine-125 remains in question. For this reason, the synthesis of 6-iodo-synkavit was examined in this study. It is finally determined that a mixture of different iodo-isomers of synkavit has been produced rather than its specific 6-iodo-isomer, when the synthetic sequence was begun with the direct sulfonation of 2-methyl-naphthalene. On the other hand, it is also determined that synkavit can directly be radioiodinated using different iodination techniques, and iodogen especially can be successfully used as an oxidative agent.
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Affiliation(s)
- T Unak
- Faculty of Science, Department of Chemistry, Ege University, Izmir, Turkey
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Abstract
In this study the microscopic energy absorption from Auger electrons of iodine-125 in colloid of two different thyroid models, which represent the normal and thyrotoxic thyroid glands, was theoretically calculated. These calculations were based on the method recently given by Unak (1987; Nucl. Intrum. Meth. Phys. Res. A255, 274) and the Auger electron spectrum given by Charlton and Booz (1981; Radiat. Res. 87, 10). Subsequently the range of highest energy Auger electrons of iodine-125 in thyroidal colloid was found to be about 72 microns. This range is considerably shorter than the radius of a normal thyroid follicle, about 150 microns, but is considerably longer than the 25 microns radius of a thyrotoxic thyroid follicle. On the other hand, the comparison of dose distributions in two different thyroid models showed that the similar activity of iodine-125 per gram of thyroid tissue is able to produce more radiotoxic effects on the thyrotoxic follicular cells.
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Affiliation(s)
- T Unak
- Faculty of Science, Department of Chemistry, Ege University, Bornova-Izmir, Turkey
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Abstract
The microscopic energy distribution along the DNA duplex due to local absorption of Auger electrons of iodine-125 incorporated into the DNA molecule, has been theoretically calculated. Our calculation method [Unak T. Nucl. Instrum. Methods A255, 274 (1987); Unak T Ibid. A255, 281 (1987)] recently presented for spatial energy distribution from low-energy electrons in different chemical systems, has also been used for these calculations. As a result, it has been determined that the maximum range of the highest energy 125I Auger electrons in a linear DNA duplex is about 38 micron, and the total energy absorbed by DNA molecule per decay is about 10.3 keV, which is approximately half of the total energy released by electrons (19.8 keV per decay). This absorbed energy is not uniformly distributed along the DNA duplex. Consequently, it has also been determined that the microscopic energy absorption per DNA base or sugar-phosphate group rapidly decreased with the distance from the 125I nuclide, and reached about 5 eV per DNA base or sugar-phosphate group at a distance of about 2 nm. On the other hand, the results also demonstrated that the local absorption of 125I Auger electrons is able to produce alone at least one double strand break (DSB) on the DNA duplex without the support of the neutralization effects of highly charged tellurium ions.
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Affiliation(s)
- P Unak
- Ege University, Faculty of Engineering, Bornova, Izmir, Turkey
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