Biomedical subjects

Perihan Unak

Publications and source records attributed to Perihan Unak.

6 recordsLinked to original sources

PubMed2006

Preparation of (99m)Tc labeled vitamin C (ascorbic acid) and biodistribution in rats.

The aim of this study was to label ascorbic acid with (99m)Tc and to investigate its radiopharmaceutical potential in rats. Ascorbic acid was labeled with (99m)Tc using the stannous chloride method. The radiochemical purity of [(99m)Tc]ascorbic acid ((99m)Tc-AA) was determined by RTLC, paper electrophoresis, and RHPLC methods. The labeling yield was found to be 93+/-5.0%. The maximum labeling yield of (99m)Tc-AA was determined at pH 5 and 25 degrees C. The biodistribution studies related to (99m)Tc-AA were done in male albino Wistar rats. (99m)Tc-AA, which has a specific activity of 13.02 GBq/mmol, was administered into the tail vein of the rats. The rats were sacrificed at 15, 30, 60, and 120 min after the injection by heart puncture under ether anaesthesia. The organs were weighed after removal. Their activities were counted using a Cd(Te) detector equipped with a RAD 501 count system. The %ID/g (% of injected dose per gram of tissue weight) in each organ and in blood was calculated. Maximum uptake of (99m)Tc-AA was observed in prostate and kidneys at the 60th min. (99m)Tc-AA may be a promising radiopharmaceutical for the imaging of prostate and kidneys.

Animals↗

PubMed2005

Radiopharmaceutical model using 99mTc-MIBI to evaluate amifostine protection against doxorubicin cardiotoxicity in rats.

The aim of our study was to use an in 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(-l) 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.

Amifostine↗

PubMed2005

Absorbed dose estimates at the cellular level for 131I.

Microdosimetric calculations of 131I have been evaluated for a single cell and for cell clusters. A VsBasic program has been used to calculate stopping power, linear energy transfer, range values and deposited energies per decay for beta particles, Auger and conversion electrons of 131I. The chemical composition of the cell has been taken into account in this model; results were compared with water medium. Besides, total absorbed doses have been calculated for the radionuclides distributed randomly within the cell and clusters. Cross-fire irradiation has been considered for clusters of cells. In this case, absorbed doses per cell within a cluster were found to be significantly higher than absorbed doses per single cell, depending on the cluster size. Results showed that 131I is a promising radionuclide for therapy of tumors from millimeter to centimeter dimensions.

Iodine Radioisotopes↗

PubMed2005

Determination of iodine concentration in urine by isotope dilution analysis and thyroid volume of school children in the west coast of Turkey after mandatory salt iodization.

OBJECTIVE: This study was designed to evaluate iodine deficiency status in children 6-12 years in the west coast (Aegean Region) of Turkey after 5 years of mandatory iodine prophylaxis. A total of 2300 children from 72 populations (rural and urban area) were evaluated with urinary iodine excretion and thyroid volume. DESIGN: Cross-sectional, observational study designed and performed according to surveillance methods for iodine deficiency disease (IDD) prevalence recommended by WHO/UNICEF/ICCIDD. SUBJECTS: The study population consisted of 2300 school children age ranging from 6 to 12 years. The children were selected by multiple stage randomization from 91 primary schools of 76 zones (91 clusters). Information about the use of iodized salt was obtained from the families. MEASUREMENTS: Data on the following were collected: birth date, sex, weight, height, thyroid size by palpation and ultrasonography; and urinary iodine by isotope dilution analysis method. Thyroid volumes above 97th percentile according to the WHO/ICCIDD by age and body surface area (BSA) were accepted as goitre. RESULTS: Iodized salt consumption was 51.7%. The prevalence of goitre determined by palpation was 12.1% and by ultrasound based on BSA and age were 9.8% and 5.5%, respectively. Median urinary iodine was 53 (2-142) microg/l. CONCLUSION: Mild to severe degree of iodine deficiency was detected in the west coast of Turkey.

Chi-Square Distribution↗

PubMed2002

A correlative study between 99mTc-ESTCPTA and 99mTc-MIBI in rats.

Tissue distribution of the 99mTc labeled derivative of the estrogen compound 3,17-alpha-estradiolyl propyl 1,4,8,11-tetraazacyclotetradecanyl-l-(4-methylbenzoic acid) ester (ESTCPTA), which has an 3,17-alpha-estradiolyl propinol coupled to l-(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 90 min 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.

Animals↗

PubMed2002

Intestinal urea metabolism: could the bacteria involved in nitrogen cycle lead to reutilization of intestinal urea nitrogen in uremic rabbits?

We aimed to evaluate the effect of bacteria involved in the nitrogen cycle on the reutilization of intestinal urea nitrogen in uremic rabbits. New Zealand white rabbits were made uremic via bilateral nephrectomy. Study and control rabbits were given live and heat-inactivated bacteria through their jejunostomies. After they were injected with 99mTc biurea intravenously, serial serum and stool levels of labeled nitrogen were assessed by instant thin-layer chromatography, and the change in the labeled-nitrogen level was determined. The serum labeled-nitrogen level increased significantly in the study group (r=0.990); however, this level decreased in the control group (r=0.662). Furthermore, the labeled-nitrogen level in the stool samples increased throughout the study in the control rabbits, but it decreased after the 6th hour in the study group. In conclusion, the results of this study suggest that when the bacterial flora of the intestinal system is changed to include bacteria involved in the nitrogen cycle in uremic rabbits, the intraintestinal and systemic nitrogen metabolisms could both be altered in favor of positive nitrogen balance.

Animals↗