Background & Aim: Calcium channel blockers are widely used in transplantation. Their immunosuppressive activity is well known and has been demonstrated in vitro and in vivo. Diltiazem as a calcium channel blocker is used in treatment protocol therapy along with immunosuppressive agent including cyclosporine (CsA) and corticosteroids in transplant patients for reducing toxicity of CsA by lowering dosage and keeping appropriate serum level of cyclosporine. The aim of this study was to evaluate the influence of diltiazem on modulation of cyclosporine doses in transplant patients.Materials and Methods: Twenty three stable kidney transplant recipients were studied in kidney transplant section of Imam Teaching Hospital, Urmia, Iran. Thirteen patient (age range 15-55) used triple therapy including Cyclosporine, azathioprine, and prednisolone along with diltiazem and ten patients (age range 18-60) used only triple therapy as a control group. 243 cyclosporine measurements during the timetable of 0, 10, 20, 25, 30, 45, 60, 90, 120, 150, 180 days after transplantation under standard condition were analyzed by radioimmunoassay technique (RIA). In this study, in addition to comparing blood levels of cyclosporine, GFR (nephrotoxicity evaluation) and liver function enzymes (ALP, SGOT, SGPT) were evaluated.Results: It was shown that the serum level of cyclosporine in patients who recieved diltiazem was significantly higher than those without having diltiazem in their treatment protocols (p<0.05). The administered doses of cyclosporine were reduced to 25% with using diltiazem which was at least equal to about 638 US dollars saving for each patient every year. In patients under triple therapy along with diltiazem, GFR (as an index of nephrotoxicity) was significantly difference from control group (p<0.05) and there was no difference between two groups in liver function tests (p>0.05). Discussion: It was speculated that clinical use of diltiazem could be useful on kidney transplantation. The main findings of this research was reducing cyclosporine nephrotoxicity, increasing blood level of CsA, and as a result reducing administered dose of cyclosporine in kidney transplant recipients.

Background: In the tube current modula on (TCM) technique, tube current is changed dynamically during the scanning process. To quan fy the effect of a dynamic tube current, a dis nct calculator is needed to es mate the CT output radia on dose in terms of volume CT dose index (CTDIvol) and individual pa ent dose in terms of size-specific dose es mate (SSDE). This study developed a specific calculator for CT scanning using the TCM technique. Materials and Methods: The tube current was extracted from the DICOM header for every slice, and averaged over the scan length. The water equivalent diameter (Dw) and SSDE values were calculated for each tube rota on. The so*ware was retrospec vely applied to 57 pa ents who had undergone abdominal and thoracic CT examina ons using a mul-detector CT, the Somatom Emo on 6. Results: The differences between the calculated CTDIvol and the CTDIvol reported by the CT scanner were 4. 4 ± 1. 2% and 6. 0 ± 2. 0% for abdominal and thoracic examina ons, respec vely. The average tube current was found to be linearly correlated with Dw with R2 values of 0. 707 and 0. 696 for abdominal and thoracic examina ons, respec vely. The average tube current was also linearly and strongly correlated with the SSDE with R2 values of 0. 941 and 0. 887 for abdominal and thoracic examina ons, respec vely. Conclusion: Calculator for es ma ng CTDIvol and SSDE specifically for TCM in CT scanning has been successfully developed. The difference between calculated CTDIvol values using this calculator and reported CTDIvol values were less than 10%.

Background: Phototherapy is an important modality in dermatology and the number of skin diseases which can be controlled with it IS mcreasmg. In order to start treatment, the first dose of phototherapy is determined by measurement of minimal erythema dose (MED) in each patient individually or according to patient"s skin type. Objective: To determine the relationship of skin type with MED in patients under UV phototherapy referred to Razi Hospital in Tehran Patients and Methods: In patients referred to Razi Hospital in 1381(2002-2003) for UVB phototherapy, skin type was determined according to Fitzpatrick"s classification and MED was measured using a UV-meter. Age, sex and the disease of the patients were also recorded. The data were analysed using one way ANOVA and Welch tests. Results: Eighty patients including 39 males and 41 females were studied. The mean age of the patients was 32 years (SD=15.8). Their diseases include psonasls, vitiligo, parapsoriasis, pityriasis lichenoides chronica, perforating disorder and patch stage mycosis fungoides. The mean of MED in 17patients with skin type Il was 111.8±39.2, in 42 patients with skin type III was 105.9±43.1 and in 21 patients with skin type IV was l14.3±39.2 mJ/cm2 , with no significant statistical difference. Conclusion: The first dose of phototherapy could not be determined based on skin type and measurement of MED is necessary in each patient.

Background: The computed tomography (CT) scan delivers a relatively high radiation dose to the patient. One of the critical factors that affects the absorbed dose is the intensity of tube current. The aim of this study is to measure and compare the radiation dose of three radiation-sensitive organs in constant current mode and tube current modulation (TCM) modes. Materials and Methods: CT-scans from the chest and abdomen-pelvis regions of adults in three different current modes were obtained. The absorbed doses of thyroid, lungs, and ovaries were measured using the thermoluminescent dosimeter (TLD) chips embedded in the RANDO phantom. Furthermore, the confirmation of the organ doses was simulated using the Monte Carlo (MC) simulation. The measured doses were evaluated and confirmed by comparison with the simulated doses. Results: The relative differences between the measured and simulated doses for thyroid, lung, and ovary were-4. 7%,-1. 3%, and-11. 7% for constant current mode,-2. 2%,-11. 2%, and-6. 3% for longitudinal modulation mode, and 0. 0%,-14. 6%, and-9. 9% for angular modulation mode, respectively. With longitudinal modulation mode, thyroid, lung, and ovary doses were reduced by 34. 0%, 19. 0%, and 19. 0% for the measured doses and 32. 0%, 26. 0%, and 13. 0% for the simulated doses, respectively. The longitudinal modulation mode resulted in a greater dose reduction compared to the angular modulation for both measured and simulated doses. Conclusion: Using TCM resulted in reducing does received by the organs in both measured and simulated doses. The TCM reduces organ dose, which is more evident in the longitudinal modulation.

N-Methyl-D-Aspartate (NMDA) receptors are involved in synaptic plasticity and neuronal communication. They have various responses to oxidative stress based on the dosage of agonists or antagonists that may be applied. This study focuses on modulation of NMDA receptors in primary hippocampal neurons in oxidative stress condition to understand the effects of NMDA receptor activation and inhibition. In our experiments, primary hippocampal neurons were treated with NMDA and MK-801 to assess their effect on cell viability and apoptosis. Oxidative stress was induced at different concentrations, to evaluate NMDA receptor activity and the neuroprotective effects of MK-801. Apoptosis rates were specified by applying flow cytometry, and assaying caspase-3 activity. Intracellular calcium levels were monitored using fluorescent dye Fura-2 AM. NMDA at 200 μM significantly prevented the cytotoxic effect induced by H2O2 (P<0.001). MK-801 with concentrations of 5 to 20 μM, could reverse the cytotoxic effect of H2O2. As a result, it significantly inhibited the toxicity of H2O2 on neuronal cells (P<0.001), while 40 μM could not reverse its effects.  NMDA (200 μM) increased neuronal survival to 88.3% in the presence of H2O2 and prevented apoptosis. MK-801 (5 μM) also elevated cell survival to 87.2%. Treatment with NMDA (200 µM) + H2O2 also did not show any changes in the Fura-2AM fluorescence compared to the H2O2 group (P>0.05). However, MK-801+ H2O2 reduced the effects of H2O2 on the fluorescence ratio and calcium influx considerably in comparison with the H2O2 group (P<0.01). Treatment with MK-801 (5 μM) effectively mitigated the effects of H2O2 on caspase-3 activity compared to the H2O2 group (P<0.001). Importantly, the dose-dependent effects of NMDA receptors offer a new path into finding therapeutic strategies for neurodegenerative diseases.

Organ dose and effective dose were estimated for one hundred patients (50 males and 50 females) who were reffered to Mashhad Ghaem Hospital for chest X-ray examination.ODS-60 software was employed for organ dose calculation. This software is capable of computing absorbed dose of 26 organs as well as effective dose. This programme is based on the ICRP-60 recommendation and Monte Carlo technique. Our results show that in PA chest X-ray lung absorbs the highest dose. The average value for males and females equals to 1.01± 0.14 and 0.58±0.10 mGy respectively. The resulting effective dose for men and women are equal to 0.246 ±0.034 and 0.178±0.033 mSv accordingly.Effective doses obtained from this research were compared with the results of other workers, also with NRPB national reference dose levels. It is concluded that effective dose as computed in this work is several times higher than similar quantities published by other workers. It implies that X-ray diagnostic procedures in Mashhad Ghaem Hospital should be re-examined and all efforts have to be made to reduce patient dose.

Introduction: The conventional methods of dosimetry are not capable of dosimetry in such a small volume of less than one cubic millimeter. Although the polymer gel dosimetry method based on magnetic resonance imaging (MRI) could achieve three dimensional dosimetry with high resolution, a spatial resolution evaluation based on gel dose modulation transfer function has not been investigated yet. Therefore, in this study, the spatial resolution of two systems of film densitometry and polymer gel dosimetry based on MRI has been evaluated by using the dose modulation transfer function (DMTF).Material and Methods: Kodak therapy verification films and MAGICA polymer gel samples were positioned below a brass absorption grid with different periodic slices (a/2=280, 525, 1125 mm), which was placed in a water bath container to avoid regions of dose build-up just below the absorption grid and then irradiated with Cobalt-60 photons on a Theratron external-beam treatment unit.Dose variation under the brass grid was determined using a calibration curve, while transverse relaxation time (T2) as the selective parameter in a dose image based on multiple echo MRI with 1.5 Tesla GE Signa Echo Speed system (FOV=10 cm, matrix size=512x512, pixel size=0.199x0.199 mm2, TE= 20, 40, 60, 80 ms, TR=4200 ms, NEX=4, slice thickness=2 mm, gap=1 mm) was calculated. DMTF from the modulation depths of T2 and variation in film optical density after calibration would be achieved. The results of polymer gel were compared with film.Results: After deriving the dose distribution profile under the absorption grid, minima and maxima at the smallest period of a=560 mm could scarcely be resolved, but the modulations due to a=2250 mm and a=1050 mm grids could be discerned. The modulation depth for a=2250 mm grid was set to 100% and the other modulations were subsequently referred to this maximum modulation. For film densitometry at a=1050 mm, the modulation depth was reduced to 35% (30% for MR based polymer gel dosimetry; MRPD) and at a=560 mm the modulation in dose was reduced to about 9% of the maximum amplitude (7% for MRPD). The DMTF for the two systems at 200 micron spatial resolution for the 2250, 1050 and 560 mm grids (0.4, 0.9 and 1.7 line pairs per mm) were equal to 1, 0.35 and 0.09 for film densitometry and 1, 0.30 and 0.07 for polymer gel.Discussion and Conclusions: Based on the results of this study, the decrease in DMTF at higher frequencies in a system in its operating resolution limit, is dependent on the type of the dosimetry system. Therefore, the assessment of DMTF for film densitometry system implied a higher spatial resolution in comparison with polymer gel dosimetry at 200 micron spatial resolution.