Türkan Ertay

New radiolabeled CCK-8 analogues [Tc-99m-GH-CCK-8 and Tc-99m-DTPA-CCK-8]: preparation and biodistribution studies in rats and rabbits

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.

Tc-99m-HMPAO uptake by bronchoalveolar cells.

Lung uptake of intravenously injected Tc-99m-HMPAO is observed in smokers and in lung toxicity due to various agents. We investigated the Tc-99m-HMPAO uptake of bronchoalveolar lavage (BAL) cells in the lungs after incubation inin vitro conditions (6 patients), intravenous injection (IV) (7 patients) and inhalation (INH) (6 patients) of Tc-99m-HMPAO in order to show whether BAL cells are also responsible for Tc-99m-HMPAO uptake in the lungs. Cell/supernatant (C/S) count ratio was 7.0±3.5, 29.3±40.8 and 8.4±4.5 forin vitro, IV and INH groups, respectively. C/Sin vitro showed a positive correlation with % alveolar macrophages (r=0.943, p=0.0048) and a negative correlation with % neutrophils (r=−0.945, p=0.0045). Cells/whole BAL fluid ratio correlated with the amount of daily cigarette consumption in INH group (r=0.95, p=0.0037). Tc-99m-HMPAO showed adherence to mucus after inhalation. Tc-99m-HMPAO diffuses into alveolar spaces after, injection and is present in BAL fluid and BAL cells both after injection and inhalation. Glutathione concentration and oxido-reductive state of the epithelial lining fluid and BAL cells may influence the lung uptake of Tc-99m-HMPAO.

Radiopharmaceutical model using 99m Tc-MIBI to evaluate amifostine protection against doxorubicin cardiotoxicity in rats

The aim of our study was to use anin vivo radiopharmaceutical model to investigate the cytoprotective effect of amifostine against doxorubicin-induced cardiotoxicity. Male Wistar rats were randomly divided into four groups (n = 6): 1) Saline (control); 2) Doxorubicin (DOX; 10 mg/ kg−1 intraperitoneally); 3) Amifostine (AMI; 200 mg/kg−1 intraperitoneally); 4) Doxorubicin plus amifostine (DOX + AMI). Amifostine was injected 30 minutes before doxorubicin in Group 4.99mTc-MIBI, 20 MBq/0.2 ml−1, was injected through the tail vein 72 hours after the drug administration. Rats were killed and samples of myocardium were removed by dissection 60 minutes after the injection of radiopharmaceutical. Radioactivity in each organ sample was counted using a Cd(Te) detector equipped with RAD 501 single-channel analyzer. The percent radioactivity was expressed as a percentage of the injected dose per gram of tissue (%ID/g−1). The %ID/g−1 activity was calculated by dividing the activity in each sample by the total activity injected and mass of each organ.99mTc-MIBI uptake as %ID/g−1 was 1.194 ± 0.502 and 0.980 ± 0.199 in the control and AMI groups, respectively. Doxorubicin administration resulted in a significant increase in %ID/ g−1 (3.285 ± 0.839) (p < 0.05). Amifostine administration 30 minutes before doxorubicin injection resulted a significant decrease in %ID/g−1’ (2.160 ± 0.791) (p < 0.05) compared with doxorubicin alone. The results showed that amifostine significantly attenuated doxorubicin-induced cardiotoxicity.

L-Carnitine Protection Against Cisplatin Nephrotoxicity In Rats: Comparison with Amifostin Using Quantitative Renal Tc 99m DMSA Uptake

Objective: In this study, we aimed to investigate the cytoprotective effect of L-carnitine against cisplatin-induced nephrotoxicity and to compare its efficacy with that of amifostin by quantitative renal Tc 99m DMSA uptake. Material and Methods: Male Wistar rats were randomly divided into six groups of six animals each. 1) Control (saline; 5 ml/kg intraperitoneally); 2) L-carnitine (CAR; 300 mg/kg intraperitoneally); 3) Amifostine (AMI; 200 mg /kg intraperitoneally); 4) Cisplatin (CIS;7 mg/kg intraperitoneally); 5) Cisplatin plus L-carnitine (CIS + CAR); 6) Cisplatin plus amifostine (CIS + AMI). L-carnitine and amifostine were injected 30 minutes before cisplatin in Group 5 and 6. Tc 99m DMSA, 7.4 MBq/0.2 ml, was injected through the tail vein 72 hours after the drug administration. Rats were killed and kidneys removed by dissection 2 hours after the injection of the radiopharmaceutical. The percentage of the injected dose per gram of kidney tissue (%ID/g) was calculated. Renal function was monitored by measuring BUN and plasma levels of creatinine. Lipid peroxidation and glutathione content were determined by measuring malondialdehyde (MDA) and reduced glutathione (GSH) in kidney tissue homogenates. Results: Tc 99m DMSA uptake per gram tissue of the kidney as %ID/g was 29.54±4.72, 29.86 ± 7.47 and 26.37 ± 4.54 in the control, CAR and AMI groups respectively. %ID/g was the lowest of all the groups, 11.60±3.59 (p<0.01), in the cisplatin group. Carnitine or amifostine administration 30 minutes before cisplatin injection resulted a significant increase in %ID/g, 21.28±7.73 and 18.97±3.24 respectively, compared to those of cisplatin-treated rats (p<0.002). A marked increase in plasma BUN and creatinine indicating nephrotoxicity and acute renal failure was observed in the cisplatin-treated group. MDA and GSH levels were concordant with cisplatin-induced oxidative stress in the kidney tissue. Conclusion: The results showed that L-carnitine significantly attenuates the cisplatin-induced nephrotoxicity as amifostin. Conflict of interest:None declared.

Enzymatic synthesis of 125/131I labeled 8-hydroxyquinoline glucuronide and in vitro/in vivo evaluation of biological influence

8-Hydroxyquinoline (8-OHQ) is a long-known molecule which due to its metal-complexation ability is frequently used for analysis. It is also called oxine. Oxine and derivatives have been investigated to process antitumor and antimicrobial activities. 8-Hydroxyquinolyl-glucuronide (8-OHQ-Glu) was enzymatically synthesized using microsome preparates separated from Hutu-80 cells, labeled with (125)I to perform a radionuclide labeled prodrug and investigated of its biological affinities on Hutu-80 (human duodenum intestinal adenocarcinoma), Caco-2 (human colorectal adenocarcinoma), Detroit 562 (human pharynx adenocarcinoma) cells and ACBRI 519 (primary human small intestine epithelial cells) in this work. UDP-glucuronyl transferase (UDPGT) rich microsome preparates, which are used for glucuronidation in enzymatic synthesis, were extracted from Hutu-80 cells. 8-OHQ-Glu components were labeled using iodogen method with (125)I and (131)I. Structural analyses were performed with LC/MS/MS, (1)H NMR and (13)C-MMR for identify and measure chemical constituents. Results confirmed expected molecular structure. 8-OHQ-Glu could successfully radioiodinated with (125/131)I according to iodogen method. (125)I-8-OHQ-glucuronide incorporated with human gastrointestinal cancer cells such as Detroit-562 (human pharynx adenocarcinoma) (12.6%), Caco-2 (human colorectal adenocarcinoma) (7.8%), Hutu- 80 (human duodenum intestinal adenocarcinoma) (9.5%) and ACBRI 519 (primary human small intestine epithelial cells) (6.40%). (131)I-8-OHQ-Glu was tested in mice bearing subcutaneously implanted Caco-2 colorectal adenocarcinoma cells. The results demonstrated that radioiodinated 8-OHQ-Glu may be promising anticancer prodrug.

Technetium-99m Hexamethylpropylene Amine Oxime Lung Scintigraphy Findings in Low-Dose Amiodarone Therapy

Amiodarone (AD)-induced pulmonary toxicity is one of the major complications of long-term AD therapy. Technetium-99m-labeled D,L-hexamethylpropylene amine oxime (Tc-99m HMPAO) scintigraphy has been used to assess lung injury. We designed this study to clarify lung uptake changes of Tc-99m HMPAO using low doses of AD (5 mg/kg/day) during long-term therapy in a rabbit model. Group 1 consisted of 7 rabbits fed with AD by gavage for 6 months. To investigate the effect of ketamine on Tc-99m HMPAO uptake, 5 rabbits were included in Group 2 as a control group. Tc-99m HMPAO scintigraphy was performed in both Group 1 and Group 2 at baseline and after 2, 4, 6, 8, and 12 weeks of AD intake. After 16, 20, and 24 weeks of drug intake, Tc-99m HMPAO scintigraphy was repeated only in group 1. One-min anterior images were acquired 30 min after the injection of 37 MBq of Tc-99m HMPAO. For semiquantitative evaluation, the mean count values were obtained and lung/background and liver/background ratios were calculated. Histopathologic evaluation was performed. No increase in lung and liver uptake of Tc-99m HMPAO was found 2, 4, 6, 8, and 12 weeks after drug intake. There was no significant increase in L/B and H/B ratios of Tc-99m HMPAO in Group 1 compared with Group 2. Both scintigraphic studies and histopathologic examinations showed nonspecific changes. Longitudinal studies investigating Tc-99m HMPAO lung uptake may be planned in patients carrying risk factors for AD-induced lung toxicity.

Lung clearance of inhaled 99Tcm-erythromycin lactobionate in non-smokers and smokers

99Tcm-labelled erythromycin lactobionate (99Tcm-EL) was used as a radioaerosol for lung ventilation imaging in humans after animal studies had shown slow clearance of 99Tcm-EL from the alveolar spaces. We performed inhalation studies in 26 volunteers: 11 non-smokers, 13 smokers (3 of whom smoked one cigarette just before inhalation of 99Tcm-EL) and 2 patients with pulmonary emboli (PE). The PE patients were imaged by both 99Tcm-EL and xenon-133 (133Xe) for comparison. The image quality with 99Tcm-EL was comparable to that with 133Xe, showing good peripheral penetration. The biological clearance half-lifes for 99Tcm-EL were 3.9 +/- 1.1 h in the non-smokers, 5.9 +/- 2.2 h in the smokers and 9.8 +/- 6.6 h in the three subjects who smoked a cigarette just before inhalation of the aerosol. 99Tcm-EL was cleared more slowly in the smokers and after smoke exposure, which could have indicated alveolar macrophage uptake. 99Tcm-EL can be used as an alternative to 99Tcm-diethylenetriamine pentaacetate (99Tcm-DTPA) in ventilation imaging, thus overcoming the problem of the fast clearance of 99Tcm-DTPA in smokers.

Effect of chemotherapy on pulmonary epithelial permeability in lung cancer

The aim of this study is to investigate the effect of one-course chemotherapy on the pulmonary epithelial permeability. Eighteen patients (18 male; mean age: 59+/-10 years) with lung cancer (11 non-small cell, 7 small cell) inhaled 40 mCi (1,480 MBq) (99m)Tc-diethylenetriaminepentaacetic acid (DTPA). Thirty images of 1-min duration were acquired from posterior projection. The first 7 min of the decay-corrected time activity curves were used to calculate lung clearance half-time. Clearance half-times of (99m)Tc-DTPA from the peripheral regions of the lungs were 42+/-19 min before and 56+/-34 min after chemotherapy (p=0.009); from the central regions, clearance half-times were 112+/-94 min before and 160+/-125 min after chemotherapy (p=0.005). This decrease in clearance rate might be related to decreasing mucociliary clearance rate due to the toxic effect of the chemotherapy regimen on cilia movement and/or mucus structure. (99m)Tc-DTPA radioaerosol study can be used to monitor the toxic effects of chemotherapy on the pulmonary epithelium and possibly on mucociliary function.

Basal and activational 99Tcm-HMPAO brain SPECT in Alzheimer's disease.

Early diagnosis in Alzheimers disease (AD) is important for the administration of new treatments. The purpose of this study was to differentiate mildly/moderately demented AD patients from normal controls by means of activational brain SPECT, and to investigate the correlation between regional cerebral blood flow and dementia severity. Activational brain SPECT was performed 1 week after basal brain SPECT in 12 mild/moderate AD patients according to NINCDS-ADRDA criteria (mean age 69±7 years) and in seven healthy, age-matched, volunteer controls (mean age 65±9 years). In order to activate the parietal cortex, patients were asked to subtract serial 5s from 100, 2 min before and after the intravenous administration of 925 MBq technetium-99m labelled D,L-hexamethyl-propylene amine oxime (99Tcm-HMPAO). Using a three-headed gamma camera equipped with high resolution collimators, 128 images of 35 s duration in a 64×64 matrix were obtained over 360°. Region to whole brain ratios (R/WB) were calculated in three consecutive transaxial slices 2 pixels thick above the orbitomeatal line, and the activation percentage was calculated. No statistical difference was detected between AD patients and normal controls for parietal cortex activation. The correlation coefficient between the Mini-Mental State Examination (MMSE) scoring and the activation percentage was 0.475 in normal controls and 0.175 in AD patients for the left anterior parietal cortex, and 0.353 in normal controls and 0.146 in AD patients for the right anterior parietal cortex. In a visual evaluation of parietal cortex activation, 50% of AD patients were able to activate the parietal cortex, whereas 86% of the normal controls could do so. In our current study, the subtraction of serial 5s was not regarded as a promising task. Further studies are needed to clarify the importance of such tasks in the differential diagnosis of mild/moderate AD patients from normal elderly.

Lung Clearance of Aerosolized 99mTc Erythromycin Lactobionate in Rabbits

In order to assess the lung clearance of aerosolized 99mTc Erythromycin Lactobionate (EL), 99mTc EL was administered to 9 New Zealand rabbits by inhalation. 5 rabbits inhaled cigarette smoke before 99mTc EL. Clearance half times were 3.0 +/- 0.9 hours in normals, 5.5 +/- 1.0 hours after smoke exposure. Clearance was not affected after destroying the surfactant layer. Slower clearance after smoke exposure may be due to the inhibition of mucociliary clearance. 99mTc EL can be considered as an alternative radioaerosol for ventilation imaging.