Stable down-regulation of HLA class-I by serum starvation in human PBMCs

Background: the human leukocyte antigen [HLA] matching between organ donor and recipient is an acceptable strategy in clinical transplantation since 1964. However, in bone marrow transplantation, finding matched donors is often problematic. Thus new method for down regulation of HLA can be an alternative strategy to solve this problem

Objective: to examine the effect of serum starvation on HLA class I expression in human peripheral blood mononuclear cells [PBMCs]

Methods: PBMCs were cultured in RPMI-1640 supplemented with 10% FBS [non-starved cells] as well as in medium only [starved cells] for 16, 24, 48, 72, 96h under standard cell culture conditions. The pattern of cell death and HLA class I expression was determined by flowcytometry. Antigenicity of the starved PBMCs was evaluated in a one-way mixed lymphocyte culture by MTT assay

Results: mean fluorescence intensity [MFI] of different indicated starved PBMCs gradually decreased and this reduction was stable after 96h of re-feeding with medium containing FBS. Under serum starvation condition, PBMCs showed apoptotic cell death pattern. There was a linear correlation between percentages of cells, which exhibited the late apoptosis death pattern and serum starvation period [r=0.88, p<0.01]. Surprisingly, the starved PBMCs lost their stimulatory property in mixed culture with allo-reactive lymphocyte

Conclusions: membrane HLA class I expression could be stably reduced in 96h starved human PBMCs culture condition, decreasing their allo-reactivity while their viability rate is enough for possible clinical application

Effects of arbutin on radiation-induced micronuclei in mice bone marrow cells and its definite dose reduction factor

Background: Interactions of free radicals from ionizing radiation with DNA can induce DNA damage and lead to mutagenesis and carsinogenesis. With respect to radiation damage to human, it is important to protect humans from side effects induced by ionizing radiation. In the present study,the effects of arbutin were investigated by using the micronucleus test for anti-clastogenic activity, to calculate the ratio of polychromatic erythrocyte to polychromatic erythrocyte plus normochromatic erythrocyte [PCE/PCE+NCE] in order to show cell proliferation activity

Methods: Arbutin [50, 100, and 200 mg/kg] was intraperitoneally [ip] administered to NMRI mice two hours before gamma radiation at 2 and 4 gray [Gy]. The frequency of micronuclei in 1000 PCEs [MnPCEs] and the ratio of PCE/PCE+NCE were calculated for each sample. Data were statistically evaluated using one-way ANOVA,Tukey HSD test, and t-test

Results: The findings indicated that gamma radiation at 2 and 4 Gy extremely increased the frequencies of MnPCE [P<0.001] while reducing PCE/PCE+NCE [P<0.001] compared to the control group. All three doses of arbutin before irradiation significantly reduced the frequencies of MnPCEs and increased the ratio of PCE/PCE+NCE in mice bone marrow compared to the non-drug-treated irradiated control [P<0.001]. All three doses of arbutin had no toxicity effect on bone marrow cells. The calculated dose reduction factor [DRF] showed DRF=1.93 for 2Gy and DRF-2.22 for 4 Gy

Conclusion: Our results demonstrated that arbutin gives significant protection to rat bone against the clastogenic and cytotoxic effects of gamma irradiation

Radioprotective effect of melatonin on radiation-induced lung injury and lipid peroxidation in rats

Free radicals generated by ionizing radiation attack various cellular components such as lipids. The lung is a very radiosensitive organ and its damage is a dose-limiting factor in radiotherapy treatments. Melatonin [MLT], the major product of the pineal gland acts as a radioprotective agent. This study aims to investigate the radioprotective effects of MLT on malondialdehyde [MDA] levels and histopathological changes in irradiated lungs. In this experimental study, a total of 62 rats were divided into five groups. Group 1 received no MLT and radiation [unT], group 2 received oral MLT [oM], group 3 received oral MLT and their thoracic areas were irradiated with 18 Gy [oM-R], group 4 received MLT by intraperitoneal [i.p.] injection and their thoracic areas were irradiated with 18 Gy [ipM-R], group 5 received only 18 Gy radiation in the thoracic area [R]. Following radiotherapy, half of the animals in each group were sacrificed at 48 hours for evaluation of lipid peroxidation and early phase lung injuries. Other animals were sacrificed in the eighth week of the experiment for evaluation of the presence of late phase radiation induced lung injuries. Pre-treatment of rats with either i.p injection [p<0.05] and oral administration of MLT [p<0.001] significantly reduced MDA levels in red blood cell [RBC] samples compared to the R group. Furthermore, i.p. injection of MLT decreased MDA levels in plasma and tissue [p<0.05]. In the early phase of lung injury, both administration of MLT sig-nificantly increased lymphocyte [p<0.05] and macrophage frequency [p<0.001]. MLT reduced the lung injury index in the lungs compared to the R group [p<0.05]. The result of this study confirms the radioprotective effect of MLT on lipid peroxidation, and in both early and late phases of radiation induced lung injuries in an animal model

[Patient dose calculation software in nuclear medicine]

Radioactive materials deliver internal radiation dose to patients in nuclear medicine. Manual internal radiation dose assessment is a complicated method. Introduction of a simple dose calculation software is the main goal of the present study. Using the best current data in internal dose calculation [S-Factors] recommended by ICRP and by considering other technical methods in Medical Internal Radiation Dosimetry [MIRD], a software was designed using Visual Basic language to calculate the total body, Gonadal as well as the fetal dose in case of pregnancy. The software is PC based and operates under windows 98, Me and XP operating systems. Patient information such as name, age and injected activity [mCi] should be entered into the system. The current software considers Tc-99m for the calculations at present time, but it is also possible to consider other radiopharmaceuticals in the software in future. After defining the source organ, the total body effective dose as well as gonadal and fetus doses can be calculated in a printable manner. This user friendly software can easily and accurately calculate the internal dose. In contrast to available commercial softwares, it can be upgraded by local experts, but MIRD method limitation should also be considered