Authors:F. Yurt Lambrecht, K. Durkan, and E. Bayrak
Bombesin (BNN)-like peptides have very high binding affinity for the gastrin-releasing peptide (GRP) receptor. The goal of
the current study was to optimize the labeling conditions of a new 99mTc-radiolabeled BNN-like peptide based on the bifunctional chelating ligand HYNIC using different co-ligands (EDDA and tricine).
The radiolabeling conditions (pH, amount of co-ligand, amount of stannous chloride, temperature and reaction time) for newly-formed
99mTc-tricine-HYNIC-Q-Litorin and 99mTc-EDDA-HYNIC-Q-Litorin were optimized and evaluated by RHPLC and RTLC. Radiochemical yields for 99mTc-tricine-HYNIC-Q-Litorin and 99mTc-EDDA-HYNIC-Q-Litorin were 98.0 ± 1.7 and 97.5 ± 2.5%, respectively. When EDDA was used as co-ligand, the labeling of 99mTc-EDDA-HYNIC-Q-Litorin was optimal in the following reaction mixture: HYNIC-peptide: EDDA: 10 μg/5 mg, pH 3, SnCl2 concentration: 12 μg/0.1 mL, reaction temperature: 100 °C, reaction time: 15 min. Besides, the optimum conditions were HYNIC-peptide:tricine:
10 μg/50 mg, pH 5, SnCl2 concentration: 12 μg/0.1 mL, reaction temperature: 100 °C, reaction time: 15 min for preparing 99mTc-tricine-HYNIC-Q-Litorin. The manufactured 99mTc-HYNIC-Q-Litorin conjugates may offer new possibilities for imaging cancer cells expressing bombesin receptors.
Authors:B. Seyitoglu, F. Yurt Lambrecht, and K. Durkan
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.
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%.
Authors:P. Ünak, F. Yurt Lambrecht, F. Biber, and S. Darcan
This study was designed to evaluate iodine concentrations in drinking water samples using isotope dilution analysis (IDA)
in the Aegean region of Turkey A total of 76 drinking water samples from rural and urban areas in regional cities were analyzed.
The mean iodine concentration was 78±27 μg/l and iodine concentration ranges were within 69±26 μg/l and 103±6 μg/l.
Authors:H. Enginar, P. Unak, F. Yurt Lambrecht, and F. Biber
An estrogen derivative 1-(3, 17-α-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
Authors:M. Sonugelen, U. ?yiyap?c? Destan, F. Yurt Lambrecht, and B. Öztürk
The objective of this study was to investigate the bacterial adherence to a non-precious alloy with radiolabeling method.
S. mutans, E. coliand C. albicanswere labeled with 99mTc by using stannous chloride and their radiolabeling yields were calculated. After the labeling procedure, metal disks (3
mm×10 mm) were treated with microorganisms. The amount of labeled microorganisms adhered on metal surfaces was determined
by activity measurements. The labeling yields for S. mutans, E. coliand C. albicanswere 69.95±7.58%, 78.84±0.44% and 79.71±10.17%, respectively. The mean values for adherence for S. mutans, E. coliand C. albicanson metal samples were 7.02±2.18%, 0.96±0.49% and 8.80±8.24%, respectively. The radiolabeling method could be considered as
safe and precise for determining the adherence of microorganisms.
Authors:F. Yurt Lambrecht, O. Yilmaz, P. Unak, B. Seyitoglu, K. Durkan, and H. Baskan
Localizing and distinguishing the “infection” in body sites are very important and life saving processes. Scintigraphic detections
may help to determine the sites of inflammation and infection. At this point, nuclear medical imaging may proceed one step
further and be helpful to localize and distinguish the inflammation. The radiolabeled antibiotic 99mTc-Cefuroxime axetil was assessed as an infection imaging agent in a rat model. In this study, 99mTc-Cefuroxime axetil was examined in localizing the normal, sterile inflamed, and septic inflamed rat muscle tissues, and
also in distinguishing each of them. The biodistribution data show that 99mTc labeled Cefuroxime axetil was retained in infectious areas. The retention was better in septic inflamed (S. aureus) area than sterile inflamed area. The clearance of the labeled antibiotic from other tissues is rapid on the contrary to
its clearance from the septic area. Target/non-target ratio shows a good value of 2.5 at 4-hour post injection when the activity
of the other organs is cleared by urinary excretion.
Authors:F. Yurt Lambrecht, O. Yilmaz, K. Durkan, P. Unak, and E. Bayrak
Linezolid is the first of new class of antibiotics, the oxazolidinones, and exhibits activity against many gram-positive organisms,
including vancomycin-resistant Enterococcusfaecium, methicillin-resistant Staphylococcusaureus, and penicillin-resistant Streptococcuspneumoniae. 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.
Authors:F. Yurt Lambrecht, O. Yilmaz, P. Unak, B. Seyitoglu, K. Durkan, S. Yolcular, and H. Baskin
The aim of this study was to evaluate 99mTc labeled human β-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.