فهرست مطالب

International Journal of Radiation Research
Volume:7 Issue: 2, Apr 2009

  • تاریخ انتشار: 1388/05/11
  • تعداد عناوین: 8
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  • Dr. J.K. Kim, T.W. Park, A. Cebulska, Wasilewska, M. Nili Page 63
    Background
    Boron and gadolinium are among the nuclides that hold a unique property of being a neutron capture therapy agent. Neutron beams have often a considerable portion of gamma rays with fast neutrons. Gamma rays, as beam contaminants, can cause considerable damage to normal tissues even if such tissues do contain high boron concentrations.
    Materials And Methods
    The modification of radioresponse in human lymphocytes pretreated with boron or gadolinium compound was studied by assessing the DNA damage using single cell gel electrophoresis (SCGE), the comet assay. The lymphocytes from the human peripheral blood were irradiated with 0, 1, 2 and 4 Gy of gamma rays from a 60Co isotopic source with or without pretreatment of boron or gadolinium compound for 10 minutes at 4oC. Post-irradiation procedures included slide preparation, cell-lysing, unwinding and electrophoresis, neutralization, staining, and analytic steps, gel electrophoresis.
    Results
    The results indicate that pretreatment with boron compound (50 nM or 250 nM of 10B) is effective in reducing the radiosensitivity of the lymphocyte DNA. Conversely, pretreatment with gadolinium compound (50 nM) led to a dose-dependent increase in the radiosensitivity, most prominently with a dose of 4 Gy (P<0.001). Furthermore, when the lymphocytes were pretreated with a combined mixture (1:1) of boron (250 nM) and gadolinium (50 nM) compounds, the reduced radiosensitivity was also observed.
  • D. Fatehi, Dr. H. Mozdarani Page 69
    Background
    To evaluate the effects of hyperthermia (HT) on the frequency of chromosomal aberrations induced by a low dose of neutron or γ-rays in human peripheral blood lymphocytes.
    Materials And Methods
    Blood samples were exposed to HT (41.5°C for 30 and 60min, 43°C for 15 and 30min), 10 cGy neutron or γ-rays, HT + neutron/γ, and neutron/γ + HT. After standard cell culture, harvesting, fixation and staining, the chromosomal damages were scored in metaphase plates.
    Results
    HT alone at 41.5°C did not induce chromatid or chromosome aberrations, however, the frequency of damages was significantly higher at 43°C (P<0.05). Furthermore, the chromosomal damages was significantly different when cells were irradiated with neutron or γ-rays alone (P<0.01). HT 1 hr post neutron/γ irradiation significantly induced higher chromosome damages in comparison to HT 1 hr before irradiation (P<0.05). The chromosomal damages were remarkably higher when cells were irradiated with neutron then heated at 43°C for 30 min.
    Conclusion
    Since increasing frequency of chromosome damages increases probability of cell death, application of HT after neutron irradiation (instead of X– or γ- rays) might be considered as a procedure for cells killing in radiotherapy.
  • Dr. K. Kant, Rashmi, R.G. Sonkawade, G.S. Sharma, R.P. Chauhan, S.K. Chakarvarti Page 79
    Background
    Radon and thoron are invisible, odorless, heavy and radioactive gases which are ubiquitously present in dwellings and in the environment. In the present work, seasonal variation of indoor radon, thoron and their progeny concentrations has been studied in the dwellings of industrially polluted cities in District Faridabad, Haryana and District Mathura in Uttar Pradesh.
    Materials And Methods
    LR -115, Type- II (Kodak Pathe, France), peelable, plastic track detectors commonly known as solid state nuclear track detectors (SSNTDs) were used to measure the radon thoron concentration over long integrated times. The measurements were carried out in the mixed field of radon and thoron and the detectors were exposed for about 90 days.
    Results
    The average value of radon and thoron concentration in the dwellings varied from 23.5 Bq/m3 to 65.2 Bq/m3 and 9.8 Bq/m3 to 18.7 Bq/m3 respectively in different seasons. The average annual exposure and annual effective dose in living rooms due to radon and thoron progeny was estimated to be 0.195 WLM (working level month) and 0.74 mSv respectively. The average life time fatality risk of lung cancer from the chronic radon and thoron progeny exposure was estimated to be 5.8 ´ 10-3 (0.58%).
    Conclusion
    The seasonal variations of measured radon levels in the environment of LPG bottling plant, radon-thoron levels and inhalation dose due to radon and thoron and their progeny in dwellings indicate that the levels were higher in winter (October to January) than in summer (April to July).
  • Dr. P.K. Manigandan Page 85
    Background
    A field study on the transfer of primordial radionuclides 238U, 232Th, 40K and fallout radionuclides 210Po in different plant species in tropical forest of western Ghats environment is presented.
    Material And Methods
    The Top storey, Second storey, Shrubs and epiphytic plant species were chosen and concentration of these radionuclides in plant and soil were measured by employing gamma ray spectrometer and alpha counter.
    Results
    The concentration ratio shows the variation in different species while a wild plant Elaeocarpus oblongus and epiphytic plants indicated preferential uptake of these radionuclides.
    Conclusion
    The dust trapped in the root system of epiphytic plants could be used as bioindicator to monitor fallout radionuclides in the Western Ghats. The concentration of 232Th and 40K in leaves depends on the age of the leaves.
  • S.J. Hosseinimehr, Dr. D. Beiki, A. Kebriaeezadeh, A. Khalaj, M. Pirali Hamedani, Sh. Akhlaghpoor, H. Esmaeili, A.R. Barazesh Page 91
    Background
    The aim of this study was to evaluate the radioprotective capacity of some novel aminoalkylated dithiocarbamic acid potassium salts against γ-irradiation in mice.
    Materials And Methods
    Eight compounds containing 2-aminoethyl-, 3- aminopropyl-, 4-aminobutyl-, 5-aminopentyl-, 6- aminohexyl-, 7-aminoheptyl-, 8-aminooctyl and 9- aminononyl of dithiocarbamate derivatives were prepared. Male NMRI mice were injected intraperitoneally (IP) with a geometric progression of doses (300 -1000 mg/kg), through the dose response range for lethal toxicity. To evaluate the radioprotecive activity, one-half of the toxic LD50 of each compound were injected IP to groups of twenty mice, 30 minutes prior to γ-irradiation. The treated animals were kept for 30 days, and the lethality was recorded each day.
    Results
    Among Eight compounds of alkyl dithiocarbamic acid derivatives, 5-aminopentyl, 7-aminoheptyl, 8-aminooctyl and 9-aminononyl dithiocarbamic acid mono potassium salts are new compounds. All evaluated compounds showed a concentrationdependent effect on the survival in mice. The LD50 values were found to be more than 599 mg/kg. The percentages of 30-day survival of mice for 2- aminoethyl, 7-aminoheptyl and 8-aminooctyl dithiocarbamic acid derivatives were 7%, 40% and 13.5%, respectively, when injected 30 minutes before γ- irradiation. Other compounds had no radioprotective effects. Statistical analysis showed a significant difference between the treated and control groups for the 7-aminoheptyl derivative (p<0.05).
    Conclusion
    Among the compounds investigated in this study, 7- aminoheptyl dithiocarbamate derivative showed more radioprotective effects in comparison with the others. Although it seems that the radioprotective effects in these derivatives correlate with the size of the alkyl chain, more experiments are required to support this hypothesis.
  • Dr. M. Gandomkar, R. Najafi, M. Mazidi, S.H. Mirfallah, M. Goudarzi Page 97
    Background
    UBI 29-41 (a derivative of antimicrobial peptide ubiquicidin) labelled with 99mTc is reported to discriminate between bacterial infections and sterile inflammatory processes. In this study, three lyophilized kit were performed, one of them based on the direct labelling with only SnCl2 as reducing agent, and other two based on 6- hydrazinopyridine-3-carboxylic acid (HYNIC) and tricine as a coligands with or without ethylenediamine -N,N’-diacetic acid (EDDA).
    Materials And Methods
    Synthesis of UBI 29-41 was performed on solid phase using a standard Fmoc strategy. BOC-HYNIC was conjugated with peptide in solution. Three lyophilized kits were prepared as follows: kit 1: 40 μg UBI 29-41, 5 μg SnCl2, pH = 9; kit 2: 40 μg UBI 29-41, 40 μg SnCl2, 20 mg tricine, pH = 5.2; kit 3: 40 μg UBI 29- 41, 40 μg SnCl2, 15 mg tricine, 5 mg EDDA, pH = 7. With addition of 99mTcO4- solution, kits were labeled under specific conditions, and the radiochemical purity was evaluated by ITLC and HPLC methods. Stability and protein binding in human serum followed by in vitro binding to bacteria were assessed. Biodistribution of radiopeptides in staphylococcus aureus infected rats muscles were studied using ex vivo counting and scintigraphy.
    Results
    Radiochemical analysis indicated rapid and high labeling yield (>95%) for the three kits. Binding to bacteria for kit 2 was to some extent higher than that was obtained for the two other kits. Specific accumulation in infected thigh muscles, as indicated by T/NT ratios was 3.29, 4.6 and 3.77 for kit 1, 2 and 3, respectively.
    Conclusion
    The HYNIC-UBI 29-41 labeled in presence of tricine as coligands (kit 2) showed the most promising results for further in vivo evaluation.
  • Dr. A.R. Jalilian, M. Tajik, H. Zandi, J. Garousi, F. Bolourinovin Page 105
    Background
    Oxytocin (OT) is a paracrine hormone with various biological activities and many sex organs in both sexes, as well as many tumor cells have shown to have related receptors. In this study the development of a receptor imaging tracer for possible tumor imaging has been described.
    Materials And Methods
    OT was successively labeled with [67Ga]-gallium chloride after conjugation with freshly prepared cyclic DTPA-dianhydride. The best results of the conjugation were obtained by the addition of 1 ml of a OT pharmaceutical solution (2 mg/ml, in phosphate buffer, pH=8) to a glass tube pre-coated with DTPA-dianhydride (0.02 mg) at 25°C with continuous mild stirring for 30 min. Radiochemical purity (RCP) of the labeled compound was determined, using RTLC and ITLC followed by stability tests and animal biodistribution studies.
    Results
    Radiolabeling took about 60 minutes with a RCP higher than 98 % at optimized conditions (specific activity = 1000 Ci/mM, labeling efficiency 80%). The stability of the tracer at room temperature was significant, up to an hour. Preliminary in vivo studies in normal female rat model showed ovary/blood and ovary/muscle ratio uptake of the tracer in 60 minutes to be 4.53 and 9.18, respectively. The result was consistent with the reported OT receptor distribution in normal female mammals.
    Conclusion
    The radiolabeled oxytocin, prepared in this study, was a possible fast acting tracer for OT receptor imaging; studies however, more studies are required to determine the best imaging conditions especially in larger mammal animals.
  • Dr. A. Chaparian, M.A. Oghabian, V. Changizi Page 113
    Background
    Recently, it has been indicated that X-ray coherent scatter from biological tissues can be used to access signature of tissue. Some scientists are interested in studying this effect to get early detection of breast cancer. Since experimental methods for optimization are time consuming and expensive, some scientists suggest using simulation. Monte Carlo (MC) codes are the best option for radiation simulation; however, one permanent defect with MC codes has been the lack of a sufficient physical model for coherent (Rayleigh) scattering, including molecular interference effects.
    Materials And Methods
    It was decided to obtain molecular interference functions of coherent X-ray scattering for normal breast tissues by combination of modeling and experimental methods. A Monte Carlo simulation program was written to simulate the angular distribution of scattered photons for the normal breast tissue samples. Moreover, experimental diffraction patterns of these tissues were measured by means of energy dispersive X-ray diffraction (EDXRD) method. The simulation and experimental data were used to obtain a tabulation of molecular interference functions for breast tissues.
    Results
    With this study a tabulation of molecular interference functions for normal breast tissues was prepared to facilitate the simulation diffraction patterns of the tissues without any experimental.
    Conclusion
    The method may lead to design new systems for early detection of breast cancer.