Activation of immunological network by chronic low-dose-rate irradiation in wild-type mouse strains: Analysis of immune cell populations and surface molecules

Background Previous studies have shown that combined treatment with internal ultra-low dose-rate irradiation selectively inactivated hypoxic T–47D breast cancer cells after three to five weeks of treatment. However, 2–3% of the hypoxic cells were found to survive and restart proliferation upon re-oxygenation. Purpose To investigate the metastatic potential and characteristics of radiosensitivity of these surviving cells, named T – 47 DS. Material and Methods The T – 47 DS cells were grown in ambient air without irradiation. A cloning experiment identified two sub-groups with different DNA content ([Formula: see text] and [Formula: see text]). Furthermore, radiosensitivity and presence of hyper-radiosensitivity (HRS) was measured by Co-60 challenge irradiation and relative migration was determined by scratch assays. Results The two subpopulations of T – 47 DS had different DNA content; one had abnormally high DNA content ([Formula: see text]) and one had DNA content similar to wild-type T–47D cells ([Formula: see text]). HRS was surprisingly present in cells of the cloned population [Formula: see text], but was absent in cells of both [Formula: see text] and T – 47 DS. The radio response of T – 47 DS, [Formula: see text] at higher radiation doses were similar to that of T-47D cells, and neither subpopulation showed increased migration compared with wild-type T–47D. Conclusion No increase in the risk of metastasis was found and only slight changes in radiosensitivity in response to conventional clinical doses was observed. Thus, the data suggest that if ultra-low dose-rate irradiation is used for targeting the hypoxic tumor fraction, conventional high dose-rate irradiation can be used to eradicate eventual surviving cells as well as cells in the well oxygenated areas of the tumor.

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Low Dose-Rate Irradiation of Gamma-Rays-Induced Cytotoxic and Genotoxic Alterations in Peripheral Erythrocytes of p53-Deficient Medaka (Oryzias latipes)

Frontiers in Marine Science ◽

10.3389/fmars.2021.773481 ◽

2021 ◽

Vol 8 ◽

Author(s):

Alaa El-Din H. Sayed ◽

Kento Nagata ◽

Takuya Nakazawa ◽

Hiroshi Mitani ◽

Junya Kobayashi ◽

...

Keyword(s):

Cell Death ◽

Dose Rate ◽

Gamma Rays ◽

Low Dose ◽

Apoptotic Cell ◽

Oryzias Latipes ◽

Wild Type ◽

Nuclear Abnormalities ◽

Morphological Alterations ◽

Low Dose Rate

Morphological alterations and nuclear abnormalities in fish erythrocytes have been used in many studies as bioindicators of environmental mutagens including ionizing radiation. In this study, adult Japanese medaka (Oryzias latipes) were irradiated with gamma rays at a low dose rate (9.92 μGy/min) for 7 days, giving a total dose of 100 mGy; and morphological alterations, nuclear abnormalities, and apoptotic cell death induced in peripheral erythrocytes were investigated 8 h and 7 days after the end of the irradiation. A variety of abnormalities, such as tear-drop cell, crenated cell, acanthocyte, sickled cell, micronucleated cell, eccentric nucleus, notched nucleus, and schistocyte, were induced in the peripheral erythrocytes of the wild-type fish, and a less number of abnormalities and apoptotic cell death were induced in the p53-deficient fish. These results indicate that low dose-rate chronic irradiation of gamma rays can induce cytotoxic and genotoxic effects in the peripheral erythrocytes of medaka, and p53-deficient medaka are tolerant to the gamma-ray irradiation than the wild type on the surface.

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Low-dose rate brachytherapy for patients with low or intermediate-risk prostate cancer. Analysis of relapse-free survival

Experimental and Сlinical Urology ◽

10.29188/2222-8543-2019-11-2-44-49 ◽

2019 ◽

Vol 11 (2) ◽

pp. 44-49

Author(s):

V.A. Solodky ◽

◽

A.Yu. Pavlov ◽

A.D. Tsybulskiy ◽

A.S. Pchelintsev ◽

...

Keyword(s):

Prostate Cancer ◽

Dose Rate ◽

Low Dose ◽

Intermediate Risk ◽

Relapse Free Survival ◽

Free Survival ◽

Low Dose Rate ◽

Risk Prostate Cancer ◽

Low Dose Rate Brachytherapy

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LOW-DOSE-RATE OR HIGH-DOSE-RATE BRACHYTHERAPY IN COMBINATION WITH EXTERNAL BEAM RADIOTHERAPY FOR INTERMEDIATE AND HIGH-RISK PROSTATE CANCER

Problems in oncology ◽

10.37469/0507-3758-2018-64-1-79-83 ◽

2018 ◽

Vol 64 (1) ◽

pp. 79-83

Author(s):

Vladimir Solodkiy ◽

Andrey Pavlov ◽

Aleksey Tsybulskiy ◽

Anton Ivashin

Keyword(s):

Prostate Cancer ◽

High Risk ◽

Dose Rate ◽

Low Dose ◽

External Beam Radiotherapy ◽

Combined Treatment ◽

High Dose ◽

External Beam ◽

Low Dose Rate ◽

Risk Of Progression

Introduction. One of the main problems of modem on-courology is treatment for prostate cancer of intermediate and high risk of progression. Modern radiotherapy in this category of patients has an advantage over surgical methods of treatment. One way to improve the effectiveness of radiotherapy is to escalate the dose in the prostate gland. For this purpose a combination of brachytherapy and remote radiotherapy is used. This combination allows increasing the dose of radiation, thereby providing better local control, reducing complications from neighboring organs. Purpose of the study. To conduct a comparative analysis of efficacy and safety of radical treatment of patients with prostate cancer at medium and high risk of progression using a combination of high and low dose rate brachytherapy with external beam radiotherapy. Materials and methods. 107 patients with prostate cancer of the group of medium and high risk of progression combined treatment (brachytherapy with external beam radiotherapy) was conducted. 53 patients underwent combined treatment (HDR-brachytherapy and external beam radiotherapy). 54 patients underwent combined treatment (LDR-brachytherapy and external beam radiotherapy). The observation period was 5 years. Conclusion. In a comparative analysis in groups of combined radiotherapy with the use of high-dose and low-dose-rate brachytherapy, the same effectiveness of immediate and long-term results of treatment was demonstrated. A significant reduction in early and late toxic reactions in patients with high-power brachytherapy has been demonstrated.

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