English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Deep-space travel presents risks of exposure to ionizing radiation composed of a spectrum of low-fluence protons ( 1 H) and high-charge and energy (HZE) iron nuclei (e.g., 56 Fe). When exposed to galactic cosmic rays, each cell in the body may be traversed by 1 H every 3-4 days and HZE nuclei every 3-4 months. The effects of low-dose sequential fractionated 1 H or HZE on the heart are unknown. In this animal model of simulated ionizing radiation, middle-aged (8-9 months old) male C57BL/6NT mice were exposed to radiation as follows: group 1, nonirradiated controls; group 2, three fractionated doses of 17 cGy 1 H every other day ( 1 H × 3); group 3, three fractionated doses of 17 cGy 1 H every other day followed by a single low dose of 15 cGy 56 Fe two days after the final 1 H dose ( 1 H × 3 + 56 Fe); and group 4, a single low dose of 15 cGy 56 Fe followed (after 2 days) by three fractionated doses of 17 cGy 1 H every other day ( 56 Fe + 1 H × 3). A subgroup of mice from each group underwent myocardial infarction (MI) surgery at 28 days postirradiation. Cardiac structure and function were assessed in all animals at days 7, 14 and 28 after MI surgery was performed. Compared to the control animals, the treatments that groups 2 and 3 received did not induce negative effects on cardiac function or structure. However, compared to all other groups, the animals in group 4, showed depressed left ventricular (LV) functions at 1 month with concomitant enhancement in cardiac fibrosis and induction of cardiac hypertrophy signaling at 3 months. In the irradiated and MI surgery groups compared to the control group, the treatments received by groups 2 and 4 did not induce negative effects at 1 month postirradiation and MI surgery. However, in group 3 after MI surgery, there was a 24% increase in mortality, significant decreases in LV function and a 35% increase in post-infarction size. These changes were associated with significant decreases in the angiogenic and cell survival signaling pathways. These data suggest that fractionated doses of radiation induces cellular and molecular changes that result in depressed heart functions both under basal conditions and particularly after myocardial infarction.

Different Sequences of Fractionated Low-Dose Proton and Single Iron-Radiation-Induced Divergent Biological Responses in the Heart