[en] In continuation of our earlier study on the involvement of heat shock protein (HSP) 25 and HSP70 in the induction of adaptive response, we have now examined the involvement of these proteins in the induction of the adaptive response, using an animal model system. C57BL6 mice were irradiated with 5 cGy of gamma radiation 3 times for a week (total of 15cGy) and a high challenge dose (6Gy) was given on the day following the last low dose irradiation. Survival rate of the low dose pre-irradiated mice was increased to 30%. Moreover, high dose-mediated induction of apoptosis was also reduced by low dose pre-irradiation. To elucidate any link existing between HSP and induction of the adaptive response, reverse transcriptase (RT)-polymerase chain reaction (PCR) analysis was performed using splenocytes. High dose radiation up-regulated the expression of HSP25 and especially HSP70; while expression of other HSPs such as HSC70, HSP90, and a-crystalline did not change. When splenocytes from HSP70 transgenic mice were pre-irradiated with a low dose of radiation, a reduction in cell death by high dose radiation was observed. These results, suggest that HSP70 is a key molecule in the induction of adaptive response

[en] The effect of radiofrequency (RF) radiation in the cellular phone communication range (836.5 MHz and 1.765 GHz code division multiple access, CDMA) on tumorigenesis and other health effect was measured using the in vitro cell culture system. To determine whether 836.5 MHz or 1.765 GHz CDMA radiations have any genotoxic effects to induce neoplastic transformation, C3H 10T1/2 cells were exposed to either of the above radiations at a specific absorption rate (SAR) of 35.6W/Kg (836.5 MHz) and 38.2 W/kg(1.765 GHz) or sham- exposed at the same time for 7 days. Cells were maintained in incubators and refed with fresh growth medium every 3 days. At this SAR, radiofrequency radiation did not induce neoplastic transformation in vitro. The extent of alteration in the kinetics of cell proliferation indicated no significant differences between RF-radiation- and sham-exposed cells with respect to MTS assay and 8-OHdG. Under this experimental conditions tested, there is no evidence for the induction of genotoxic indices in human and mouse cells exposed in vitro for 7 days to 836.5 MHz or 1.765 GHz RF radiation at SARs of up to 35.6 or 38.2 W/kg

[en] In continuation of our earlier study on the involvement of Heat Shock Protein (HSP) 25 and HSP70 in the induction of adaptive response, we have now examined the involvement of these proteins in the induction of the adaptive response, using an animal model system. C57BL6 mice were irradiated with 5 cGy of gamma radiation 3 times for a week (total of 15cGy) and a high challenge dose (6Gy) was given on the day following the last low dose irradiation. Survival rate of the low dose pre-irradiated mice was increased to 30%. Moreover, high dose-mediated induction of apoptosis was also reduced by low dose pre-irradiation. To elucidate any link existing between HSP and induction of the adaptive response, Reverse Transcriptase (RT)-Polymerase Chain Reaction (PCR) analysis was performed using splenocytes. High dose radiation up-regulated the expression of HSP25 and especially HSP70; while expression of other HSPs such as HSC70, HSP90, and a?-crystalline did not change. When splenocytes from HSP70 transgenic mice were pre-irradiated with a low dose of radiation, a reduction in cell death by high dose radiation was observed. These results, suggest that HSP70 is a key molecule in the induction of adaptive response

[en] Human bone marrow mesenchymal stem cells (hBMMSCs) are multipotent stem cells that can differentiate into several specialized cell types, including bone, cartilage, and fat cells. The proliferative capacity of hBMMSCs paves the way for the development of regenerative medicine and tissue engineering. However, long-term in vitro culture of hBMMSCs leads to a reduced life span of the cells due to senescence, which leads eventually to growth arrest. To investigate the molecular mechanism behind the cellular senescence of hBMMSCs, microarray analysis was used to compare the expression profiles of early passage hBMMSCs, late passage hBMMSCs and hBMMSCs ectopically expressing human telomerase reverse transcriptase (hTERT). Using an intersection analysis of 3892 differentially expressed genes (DEGs) out of 27,171 total genes analyzed, we identified 338 senescence-related DEGs. GO term categorization and pathway network analysis revealed that the identified genes are strongly related to known senescence pathways and mechanisms. The genes identified using this approach will facilitate future studies of the mechanisms underlying the cellular senescence of hBMMSCs