Phenolphthalein-glucuronide is a commonly used glucuronide conjugate for beta-glucuronidase measurements. The quantity of
phenolphthalein liberated by beta-glucuronidase is measured spectrophotometrically. The detection limit of the quantity of
phenolphthalein using spectrophotometry is a few μg. In this study, a new radioanalytical technique for the measurement of
beta-glucuronidase was applied which is 106times more sensitive than the spectrophotometric technique. Radioiodinated phenolphthalein-glucuronide and phenyl-N-glucuronide
were used in this study in which the beta-glucuronidase levels of some tissue samples were measured.
Authors:U. Avcıbaşı, H. Dinçalp, T. Ünak, Y. Yıldırım, N. Avcıbaşı, Y. Duman, and S. Içli
Perylene diimide denvatives are one of the G-quadruplex DNA interactive agents which are thought to be useful in application
of cancer treatment Starting from this consideration, N-(2,6-diisopropylphenyl)-N’-(4-pyridyl)-perylene-3,4,9,10-tetracarboxy
??lic diimide (PYPER) was synthesized, radioiodinated with 131I, and its radiopharmaceutical potentials were tested on a male Albino rabbit and male Albino Wistar rats. This compound was
successfully radioiodinated with 131I with a radioiodination yield of about 100%. Scintigraphic imaging with the radiiodinated compound (131I-PYPER) was performed on a rabbit. Static images were obtained from posterior projection using a Diacan gamma camera at several
time intervals. The scintigrams clearly showed that the radioiodinated compound was not quickly cleared from the metabolism,
accumulating in the stomach over about 30 minutes. The clearance time of this compound was considerably longer than 5 hours.
The results obtained in this study agreed with that of the biodistribution studies and indicated that 131I-PYPER might be used as a scintigraphic agent for examining stomach diseases.
Authors:T. Ünak, Ç. Çal, Y. Yildirim, U. Avcıbaşı, and G. Ünak
Zinc plays an important role in prostate functions. For this reason, in this study some rats have been nourished with foods
containing different zinc levels and some tissue samples removed at different intervals of time from their prostate, testis,
and seminal vesicle. The zinc contents of these samples have been determined using the isotopic dilution analysis technique
applied with 65Zn. In this way, the zinc contents of tissues varying between 0.02–4.50 μg Zn/g wet tissue could be determined with good precision.
As a result, the zinc content of the prostate was found to be considerably high with respect to the zinc contents of the testis
and the seminal vesicle. It is also interesting to note that a high zinc level in foods results in the accumulation of zinc
in the prostate rather than in the testis and the seminal vesicle. The zinc content of the seminal vesicle decreases with
a function of time passed from the beginning of the diet which contrasts with the case of prostate. It is also very remarkable
that when the level of zinc in the body is low, the content of zinc in the testis is considerably higher.
Authors:U. Avcıbaşı, H. Demiroğlu, P. Ünak, F. Müftüler, Ç. İçhedef, and F. Gümüşer
Bleomycins (BLMs; BLM, A2, and B2) were labeled with 131I and radiopharmaceutical potentials were investigated using animal models in this study. Quality control procedures were
carried out using thin layer radiochromatography (TLRC), high performance liquid chromatography (HPLC), and liquid chromatography
(LC/MS/MS). Labeling yields of radiolabeled BLMs were found to be 90, 68, and 71%, respectively. HPLC chromatograms were taken
for BLM and cold iodinated BLM (127I-BLM). Five peaks were detected for BLM and three peaks for 127I-BLM in the HPLC studies. Two peaks belong to isomers of BLM. The isomers of BLM were purified with using HPLC. Biological
activity of BLM was determined on male Albino Wistar rats by biodistribution and scintigraphic studies were performed for
BLMs by using New Zelland rabbits. The biodistribution results of 131I-BLM showed high uptake in the stomach, the bladder, the prostate, the testicle, and the spinal cord in rats. Scintigraphic
results on rabbits agrees with that of biodistributional studies on rats. The scintigraphy of radiolabeled isomers (131I-A2 and 131I-B2) are similiarly found with that of 131I-BLM.
Authors:T. Ünak, Y. Yildirim, U. Avcibasi, Z. Biber, Y. Duman, and P. Ünak
In this study, dithizone (diphenylthiocarbazone) has been separately radiolabeled with 131I and with 99mTc for preliminarily testing their radiopharmaceutical potentials on male albino rabbits. 131I-dithizone and 99mTc-dithizone were intravenously injected to rabbits via their ear veins after anesthetizing with a mixture of Alfazyne and
Alfamine (Serva) to determine their dynamic and static statuses in the metabolism. Also, 99mTc as pertechnetate and 131I as iodate were administered to rabbits as controls. Dynamic and static scintigrams were obtained using a gamma camera (Diacan
Instruments). Dynamic scintigrams were obtained over the first half hour with frames of 1 minute following the administrations
of the labeled compounds. Static images were obtained from posterior projection at different time intervals up to about 3
hours following the administration of the radiolabeled compounds. 99mTc-dithizone was significantly uptaken by the pancreas in contrast to free 99mTc. In the case of 131I-dithizone, the distribution of 131I activity in the metabolism was clearly different than the case of free 131I and the uptake of 131I-dithizone at the pancreas zone was also significant. These preliminary tests have clearly indicated that especially 99mTc-dithizone has a significant potential to be used as a pancreatic radiopharmaceutical.
Authors:T. Ünak, Z. Akgün, Y. Duman, Y. Yildirim, U. Avcibaşi, and B. Çetinkaya
Aniline-mustard and its glucuronide conjugate were radioiodinated with 131I. The preliminary dynamic tests were carried out on rabbits. The scintigrams showed clearly that the glucuronide conjugate of aniline-mustard was very quickly cleared from the metabolism, accumulating in the bladder in about 15 minutes. The clearance time of radioiodinated aniline-mustard-glucuronide was considerably longer (about 45 min.). The results obtained from the biodistributional studies have represented interesting differences between the metabolic details of radioiodinated compounds, and indicated that the glucuronide conjugate of aniline-mustard may be a promising radioiodinated prodrug, if verification of its selective accumulation in some kinds of tumor cells can be obtained.