Radiolabeling of bombesin-like peptide with Tc-99m : Tc-99m-Litorin and biodistribution in rats

WOS: 000249656100021PubMed ID: 17760415Bombesin-like peptides are related to several human cancer receptors, including small cell lung, prostate, breast, colon, and pancreatic cancers. Litorin, an amphibian bombesin peptide derivative, is found to stimulate the contraction of smooth muscle, to stimulate gastrin, gastric acid, and pancreatic secretion, and to suppress the nutriment in in vivo experiments. In the present study, litorin was labeled with 99mTc by the stannous chloride procedure. Labeling yield is 95 +/- 1.4%, as determined by radio thin layer chromatography (RTLC) and radio high performance chromatography (RHPLC). Results of in vitro studies demonstrated a high stability in serum and cysteine solutions. In vivo biodistribution was investigated with normal male Albino Wistar rats. Biodistribution data showed fast clearance, low intestinal accumulation, and significant uptake in bombesin/gastrin releasing peptide (BN/GRP) receptor rich tissues such as the pancreas (23.56 +/- 0.01 %ID/g 30 min pi). It can be blocked partially by previous administration of 'cold' litorin. The results showed specificity of the uptake. As Tc-99m-litorin displays good radiolabeling and biodistribution, it is a potentially useful radiopharmaceutical for detection of bombesin receptor-expressing cancers

Biodistribution of Tc-99m-creatinine in rats with ablation nephropathy

WOS: 000254089300034PubMed ID: 1823187

In vitro evaluation of Tc-99m- EDDA/tricine-HYNIC-Q-Litorin in gastrin-releasing peptide receptor positive tumor cell lines

WOS: 000318356800007PubMed ID: 23301856Bombesin 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. Tc-99m 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 Tc-99m-EDDA-HYNIC-Q-Litorin and Tc-99m-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.Scientific and Technological Research Council of TurkeyTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK); Scientific Project [108S200]; Ege University Science-Technology Application and Research CenterEge University [2009 BIL 025]The authors gratefully acknowledge the financial support received from the Scientific and Technological Research Council of Turkey, Scientific Project (108S200) and Ege University Science-Technology Application and Research Center (2009 BIL 025). The authors have declared no conflict of interest

Radiochemical and radiobiological evaluation of a new Tc-99m-labelled litorin derivative

WOS: 00028107510011

Preparation of I-131-Pyrimethamine and evaluation for scintigraphy of experimentally Toxoplasma gondii-infected rats

WOS: 000314475400006PubMed ID: 23113799We aimed to assess the ability of I-131-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. I-131-Pyrimethamine (specific activity: 7.08 MBq/mu 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 5 min, 45 min, 2 h, 6 h, and 24 h 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 45 min which persisted till 24 h. In conclusion, I-131-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