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Öğe Biological investigation of 131I-labeled new water soluble Ru(II) polypyridyl complex(2008) Ocakoglu K.; Yildirim Y.; Yurt Lambrecht F.; Ocal J.; Icli S.New [Ru(L1)(dcbpy)(NCS)2] complex was synthesized in a one-pot reaction starting from [RuCl2(p-cymene)]2, where the ligands (dcbpy=4,4'-dicarboxy-2,2'-bipyridine, L1=dipyrido[3,2-a:2',3'-c]phenazine-11-ylcarbonyl)-sodium) are introduced sequentially. The resulting complex was characterized by IR, NMR, and elemental analysis. The complex was labeled with I-131. Biodistribution study of the complex was carried out using 131I-labeled [Ru(L1)(dcbpy)(NCS)2] complex. The biodistribution study performed with albino Wistar male rats has shown that the complex has high uptake in the lung, small intestine, fat, and spleen. © 2007 Elsevier Ltd. All rights reserved.Öğe A correlative study between 99mTc-ESTCPTA and 99mTc-MIBI in rats(2002) Unak P.; Enginar H.; Zümrüt Biber F.; Yurt Lambrecht F.; Aslani M.A.A.; Ozkilic H.Tissue distribution of the 99mTc labeled derivative of the estrogen compound 3,17-?-estradiolyl propyl 1,4,8,11-tetraazacyclotetradecanyl-1-(4-methylbenzoic acid) ester (ESTCPTA), which has an 3,17-?-estradiolyl propinol coupled to 1-(4-methylbenzoic acid)1,4,8,11-tetraazacyclotetradecane (CPTA), was compared to 99mTc-MIBI (methoxyisobutyl isonitrile) in female Albino Wistar rats. Tissues of interest included lung, liver, heart, kidneys, spleen, stomach, intestines, pancreas, muscle, blood, breast, ovary, fat, and uterus. 99mTc-ESTCPTA uptake by the uterus and ovary, as ER-rich tissues, was highly selective. Maximum uptakes for 99mTc-MIBI and 99mTc-ESTCPTA are 90min in breast, ovary and uterus. The pancreas also showed significant receptor saturated and unsaturated ratios for 99mTc-ESTCPTA. Results are sufficiently encouraging to generate further evaluation of these and related compounds as possible estrogen receptor based tumor imaging and therapeutic agents in estrogen-rich tissues. © 2002 Published by Elsevier Science Ltd.Öğe Evaluation of 99mTc-Pheophorbide-a use in infection imaging: A rat model(2011) Ocakoglu K.; Bayrak E.; Onursal M.; Yilmaz O.; Yurt Lambrecht F.; Holzwarth A.R.This study aims to prepare 99mTechnetium Pheophorbide-a (99mTc-PH-A) complex and evaluate its efficiency as an infection imaging agent. First, PH-A was obtained from Spirulina maxima algae, and the product compound was confirmed using 1H NMR and MS (ESI) methods. The PH-A was then labeled with 99mTc using the tin chloride method and its biological efficacy as a potential radiotracer for Staphylococcus aureus (S. aureus) infection was evaluated in bacterially infected and sterile inflamed rats. The radiochemical stability of the 99mTc-PH-A in human serum was determined by thin-layer radiochromatography (TLRC). The radiochemical purity was 87±3.2% and remained constant at more than 80±0.1% even in serum for 120min after radiolabeling.These experiments indicated that the ratio of 99mTc-PH-A uptake in bacterially infected muscle, as compared to normal muscle, [target/non-target (T/NT)=5.6 at 1h] was over four times higher than that in sterile inflamed muscle (T/NT=1.29 at 1h). Disappearance of activity from the kidney and liver indicated that the urinary and hepatobiliary systems were the normal routes of excretion of the complex.99mTechnetium Pheophorbide prepared with high yield is able to localize well in the bacterially infected muscle of the rats and 99mTc-PH-A may be developed as a radiopharmaceutical agent to distinguish infection from inflammation by nuclear imaging. © 2011 Elsevier Ltd.Öğe Gamma radiation shielding efficiency of a new lead-free composite material(Kluwer Academic Publishers, 2015) Soylu H.M.; Yurt Lambrecht F.; Ersöz O.A.The aim of the study is to produce a new metal-polymer composite in the form of disc and investigate shielding efficiencies against gamma radiation (137Cs and 131I and 241Am). The composite discs were produced from mixing polymer and different percentage tungsten carbide (50, 60, and 70 %). Compared with lead in same conditions the new material is more lightweight and flexible. Moreover the material’s shielding efficiency is higher than lead also. © 2015, Akadémiai Kiadó, Budapest, Hungary.Öğe Imaging of bacterial infection with 99mTc-labeled HBD-1(2008) Yurt Lambrecht F.; Yilmaz O.; Unak P.; Seyitoglu B.; Durkan K.; Yolcular S.; Baskin H.The aim of this study was to evaluate 99mTc labeled human ß-defensin-1 (HBD-1) for discrimination between bacterial infection and sterile inflammation. For this purpose, HBD-1 was radiolabeled with 99mTc and its in vivo distribution was evaluated in inflamed rats with Staphylococcus aureus (S. aureus) and sterile inflamed rats with turpentine oil. After injection into inflamed and sterile inflamed rats, 99mTc-HBD-1 was rapidly removed from the circulation via the kidneys. Binding of 99mTc-HBD-1 to inflamed muscle (T/NT = 20 at 120 min) was two times higher than binding to sterile inflamed muscle (T/NT = 10 at 120 min) of rats. It was demonstrated that 99mTc-HBD-1 can be used to detect S. aureus inflammation in rats. However, the radiolabeled antimicrobial peptide showed only poor uptake in sterile inflammation with turpentine oil in rats. As a result, 99mTc-HBD-1 can be useful for detection of bacterial inflammation. © 2008 Akadémiai Kiadó, Budapest.Öğe In vitro evaluation of 99mTc-EDDA/tricine-HYNIC-Q-Litorin in gastrin-releasing peptide receptor positive tumor cell lines(2013) Yurt Lambrecht F.; Durkan K.; Özgür A.; Gündüz C.; Avci C.B.; Susluer S.Yi.Bombesin and its derivatives exhibit a high affinity for gastrin-releasing peptide receptor (GRPr), which is over-expressed in a variety of human cancers (prostate, pancreatic, lung, etc.). The aim of this study was to investigate the in vitro potential of the hydrazinonicotinamide (HYNIC)-Q-Litorin. 99mTc labeling was performed by using different co-ligands: tricine and ethylenediamine diacetic acid (EDDA). The radiochemical stability of radiolabeled peptide conjugates was checked at room temperature and in cysteine solution up to 24 h. The in vitro cell uptake of 99mTc-EDDA-HYNIC-Q- Litorin and 99mTc-tricine-HYNIC-Q-Litorin were evaluated on pancreatic tumor and control cell lines. Optimum specific activity and incubation time were determined for all the cell lines. The results showed that the cell uptake of the radiolabeled peptide conjugates in tumor cell lines were higher than in the control cell line. The findings of this study indicated the need for further development of in vivo study as a radiopharmaceutical for pancreatic tumor imaging. © 2013 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.Öğe Labeling of apigenin with 131I and bioactivity of 131I-apigenin in male and female rats(2009) Seyitoglu B.; Yurt Lambrecht F.; Durkan K.Apigenin (4,'5,7-trihydroxyflavone), one of the most common flavonoids, has been shown to possess a variety of biological activities including tumor growth inhibition and chemopreventation. In the present study, apigenin was labeled with 131I using iodogen method and investigated of its bioactivity. Radiolabeling yield is 98±0.2%, as determined by radio thin layer chromatography (RTLC), electrophoresis and radio high performance liquid chromatography (RHPLC). Besides, structure analysis of synthesized cold iodoapigenin complex were assessed with LCMS/MS and 1H-NMR. Results of in vitro study indicated a high stability (3 hours) in human serum. Biodistrubition studies are performed in male and female albino Wistar rats. Biodistribution data related to the male rats showed significant uptake in the small intestine. The female rats biodistribution results indicated that the uptake of 131I-apigenin was high in the intestine and uterus. © 2009 Akadémiai Kiadó.Öğe Preparation and biodistribution of [131I]linezolid in animal model infection and inflammation(2009) Yurt Lambrecht F.; Yilmaz O.; Durkan K.; Unak P.; Bayrak E.Linezolid is the first of new class of antibiotics, the oxazolidinones, and exhibits activity against many gram-positive organisms, including vancomycin-resistant Enterococcus faecium, methicillin-resistant Staphylococcus aureus, and penicillin-resistant Streptococcus pneumoniae. Aim of the study: Linezolid was to label with I-131 and potential of the radiolabeled antibiotic was to investigate in inflamed rats with S. aureus (S. aureus) and sterile inflamed rats with turpentine oil. Linezolid was labeled with I-131 by iodogen method. Biodistribution of [131I]linezolid was carried out in bacterial inflamed and sterile inflamed rats. Radiolabeling yield of [ 131I]linezolid was determined as 85 ± 1% at pH 2. After injecting of [131I]linezolid into bacterial inflamed and sterile inflamed rats, radiolabeled linezolid was rapidly removed from the circulation via the kidneys. Binding of [131I]linezolid to bacterial inflamed muscle (T/NT = 77.48 at 30 min) was five times higher than binding to sterile inflamed muscle (T/NT = 14.87 at 30 min) of rats. [131I]linezolid showed good localization in bacterial inflamed tissue. It was demonstrated that [131I]linezolid can be used to detect S. aureus inflammation in rats. © 2009 Akadémiai Kiadó.Öğe Preparation of 131I-Pyrimethamine and evaluation for scintigraphy of experimentally Toxoplasma gondii-infected rats(2013) Inceboz T.; Yurt Lambrecht F.; Surucu E.; Yilmaz O.; Yavasoglu A.; Durkan K.; Baykara B.; Bekis R.; Uner A.We aimed to assess the ability of 131I-Pyrimethamine scintigraphy to detect the lesions of Toxoplasma gondii infection. An experimental model of toxoplasmosis was developed. The presence of toxoplasmosis was confirmed 60 days after implantation. Pyrimethamine was radioiodinated with I-131. The radioligand was validated by the requisite quality control tests to check its radiolabeling efficiency, in vitro stability and radiochemical purity etc. 131I-Pyrimethamine (specific activity: 7.08 MBq/mol) was injected intravenously into the tail vein of the control and infected rats. Static whole body images of the rats were acquired under the gamma camera at 5min, 45min, 2h, 6h, and 24h following the intravenous administration of the radioactivity (3.7 MBq/rat). Then the scintigraphic data were analyzed both visually and semiquantitatively. Regions of interest (ROIs) were drawn over the organs (thyroid, stomach, liver, bladder, and soft tissues) to calculate the ratios of the radiotracer in infected vs. control rats. The mean ratio of radiotracer in infected/control rats in the liver and diaphragm was over 1 at 45min which persisted till 24h. In conclusion, 131I-Pyrimethamine may be useful agent for diagnosis toxoplasmosis especially involving liver and diaphragm, needs further preclinical validation before being extended for use in clinical applications. © 2013 Informa UK, Ltd.Öğe Preparation, quality control and stability of 99mTc-cefuroxime axetil(2008) Yurt Lambrecht F.; Durkan K.; Unak P.Cefuroxime axetil, a cephalosporin antibiotic used to treat bacterial infections, was investigated to label with 99mTc. Radiolabeling of cefuroxime axetil was carried out by using stannous chloride method. Effects of pH and stannous chloride amount on the radiolabeling yield were investigated. The radiochemical purity of 99mTc-cefuroxime axetil was determined by thin layer radio chromatography (TLRC), electrophoresis and high performance liquid chromatography. The maximum radiolabeling yield was 98±1%. © 2008 Springer Science+Business Media, LLC.Öğe Radiolabeling of folate targeted multifunctional conjugate with Technetium-99m and biodistribution studies in rats(2012) Ak G.; Yurt Lambrecht F.; Sanlier S.H.Despite the progress in the diagnosis and management of early stage disease, the management of advanced prostate cancer remains an important problem. Prostate tissue expresses folate receptor (FR) which binds both folic acid and folate-linked drugs or imaging agents. Doxorubicin is the best known and most widely used member of the anthracycline antibiotic group of anticancer agents. The aim of this work is to develop a multifunctional nanoconjugate, 99mTc-folatePEGdoxorubicin, in order to investigate its radiopharmaceutical potential as a prostate cancer imaging and real-time drug location imaging agent. Through this aim, biodistribution studies of 99mTc-folatePEGdoxorubicin and control groups ( 99mTcdoxorubicin and 99mTcPEGdoxorubicin) in male rats were carried out. Obtained data showed that uptake of 99mTc- folatePEGdoxorubicin in prostate was significantly higher than that of the control groups due to the affinity of folate ligand to folate receptor. As a consequence, it was indicated that 99mTc-FOLPEGDOX radiolabeled conjugate which has a great target/non-target organ ratio, is specific for target organ and has a high radiopharmaceutical potential as a prostate cancer and real-time drug location imaging agent. © 2012 Informa UK, Ltd.Öğe Synthesis of a 99mTc labeled estrogen-derivative and the determination of its radiopharmaceutical potential on rats(2004) Enginar H.; Unak P.; Yurt Lambrecht F.; Biber F.Z.An estrogen derivative 1-(3, 17-?-estradiolyl propin-1-yl-3-(1,4,8, 11-tetraazacyclotetradecyl)-propanate (ESTACPA) was synthesized. The product was purified by HPLC and characterized by NMR and IR spectroscopy. The synthesized compound was labeled with 99mTc. The biodistribution studies were performed on female Albino Wistar rats. The rats were sacrificed and their organs were removed. The radioactivities of the organs were counted using a gamma-counter. The activity per gram tissue was calculated and time versus activity curves were generated. The 99mTc-ESTACPA uptake by the uterus and ovary such as ER-rich tissues, were observed. The pancreas and stomach also showed a significant uptake.
