جستجوی مقالات مرتبط با کلیدواژه « اثر همسایگی » در نشریات گروه « پزشکی »

The biological response of cells that are not directly exposed to radiation, but are in the vicinity or the environment of irradiated cells, is known as the radiation bystander effect. In previous studies, the existence and mechanism of the bystander effect induced by ionizing radiation have been investigated. Recently, ultrasound therapy was inducted as a new method for treating some cancers. Therefore, it seems necessary to evaluate the ultrasound-induced bystander effect.

To investigate the ultrasound-induced bystander effect, A375 and MCF-7 cell lines were cultured in the target and bystander plates. The target plates included four groups of control (without intervention), ultrasound, gold nanoparticles, and simultaneous ultrasound treatment and gold nanoparticles. The four bystander groups received the culture medium of the target groups, respectively. MTT and colony forming units assays were </em>performed to investigate the ultrasound induced bystander effect.

The percentage of colonization in bystander groups receiving ultrasound without and with gold nanoparticles were significantly lower compared with the control group. However, the amount of colonization for the MCF-7 cell line was more than A375.

The results showed that the ultrasound-induced bystander effect was intensified in the presence of gold nanoparticles due to.

The use of ultrasound waves in combination with chemotherapy drugs increases the effectiveness of the drug in low doses. Moreover, in the treatment process, cells that have not been directly treated undergo a variety of changes such as death; this phenomenon is known as the bystander effect. This study aimed to investigate the effect of combined treatment of ultrasound waves and cisplatin on the bystander cells in melanoma cells.

Melanoma A375 cells were first cultured in the laboratory. After culturing the cells, two target and bystander cell groups were considered for the experiments. After determining the optimal concentration of cisplatin for melanoma A375 cells by MTT test, the target group cells were treated with the optimal concentration of cisplatin and ultrasound with intensities of 0.5, 1, and 2 w/cm2 . After 24 hours, the culture medium of the target cells was collected and added to the bystander cells using the medium transfer technique. At 24 hours, MTT assay was used to measure cell viability.

The survival percentage of melanoma cells in the bystander group, which received the culture medium of the treated cells by combination of cisplatin and ultrasound waves with an intensity of 2 W/cm2 , had a significant decrease compared to the control group.

In combination therapies with ultrasound waves and chemotherapy drugs, the role of the bystander effect on the efficiency of treatment and cell survival should also be considered.

Bystander effect is defined as biological responses observed in cells that are not exposed to radiation directly but these radiation effects are induced through messages from irradiated cells. One of the non-invasive methods for cancer treatment is ultrasound waves. The therapeutic efficacy of ultrasound waveslike treatment with ionizing radiation can be altered by the bystander effect, so it is necessary to evaluate the bystander effect after ultrasound exposure. In this study, the effect of ultrasound exposure on the expression of P53 gene in neighboring cells has been investigated.

The cells were divided into three groups: control (without treatment), target (under direct ultrasound exposure) and the bystander (no radiation, only receiving target cells culture media). In the target group, the cells were exposed to the ultrasound and after one hour their culture medium were transferred to the bystander group. Cell viability and the expression of P53 gene by using the MTT assay and Real-time PCR was analyzed.

The percentage of cell survival in the target group was reduced compared to the control group, but in the bystander group, this difference was not significant. The expression of P53 gene in the bystander group was statistically increased compared to the control group.

The bystander effect is induced after ultrasound exposure and it can increase the level of P53 gene expression in bystander cells.

Radioadaptive response (RAR) describes a phenomenon in which small priming doses of ionizing radiation (IR) reduce detrimental effects of subsequent higher doses. Since IR-induced carcinogenesis is a main concern in the low-dose radiation risk assessmen, the aim of this study was to investigate the RAR with the end points of carcinogenesis and the related genomic damages and evaluation of the effective in-vivo mechanisms in this phenomenon.

The present review article was performed by using the research and review articles indexed in Pubmed, Google scholar, Science direct. In this review article, some resent studies related to RAR with end points of carcinogenesis in different species of mice and human lymphocytes has been investigated. Additionally, in the present review article, the role of important in vivo mechanisms involved in adaptive response, namely DNA repair, bystander effect and endocrine system hormones such as glucocorticoids has been investigated.

These studies, often revealed efficient induction of RAR by chronic or repeated low-dose priming irradiation.

Current radiation protection regulations do not include RAR because of the large variability in expression among individuals and uncertainties of the mechanism. However, in the future, RAR should be regarded as an indispensable factor for estimation and control of individual IR sensitivity.