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Recently developed short‐pulsed laser sources garner high dose‐rate beams such as energetic ions and electrons, x rays, and gamma rays. The biological effects of laser‐generated ion beams observed in recent studies are different from those triggered by radiation generated using classical accelerators or sources, and this difference can be used to develop new strategies for cancer radiotherapy. High‐power lasers can now deliver particles in doses of up to several Gy within nanoseconds. The fast interaction of laser‐generated particles with cells alters cell viability via distinct molecular pathways compared to traditional, prolonged radiation exposure. The emerging consensus of recent literature is that the differences are due to the timescales on which reactive molecules are generated and persist, in various forms. Suitable molecular markers have to be adopted to monitor radiation effects, addressing relevant endogenous molecules that are accessible for investigation by noninvasive procedures and enable translation to clinical imaging. High sensitivity has to be attained for imaging molecular biomarkers in cells and in vivo to follow radiation‐induced functional changes. Signal‐enhanced MRI biomarkers enriched with stable magnetic nuclear isotopes can be used to monitor radiation effects, as demonstrated recently by the use of dynamic nuclear polarization (DNP) for biomolecular observations in vivo. In this context, nanoparticles can also be used as radiation enhancers or biomarker carriers. The radiobiology‐relevant features of high dose‐rate secondary radiation generated using high‐power lasers and the importance of noninvasive biomarkers for real‐time monitoring the biological effects of radiation early on during radiation pulse sequences are discussed.

Pyruvate membrane crossing and its lactate dehydrogenase-mediated conversion to lactate in cells featuring different levels of expression of membrane monocarboxylate transporters (MCT4) were probed by dissolution dynamic nuclear polarization-enhanced NMR. Hyperpolarized 13 C-1-labeled pyruvate was transferred to suspensions of rodent tumor cell carcinoma, cell line 39. The pyruvate-to-lactate conversion rate monitored by dissolution dynamic nuclear polarization-NMR in carcinoma cells featuring native MCT4 expression level was lower than the rate observed for cells in which the human MCT4 gene was overexpressed. The enzymatic activity of lactate dehydrogenase was also assessed in buffer solutions, following the real-time pyruvate-to-lactate conversion speeds at different enzyme concentrations. Copyright © 2016 John Wiley & Sons, Ltd.

Long-lived states (LLS) are relaxation-favored spin population distributions of J-coupled magnetic nuclei. LLS were measured, along with classical 1H and 15N relaxation rate constants, in amino acids of the N-terminal Unique domain of the c-Src kinase, which is disordered in vitro under physiological conditions. The relaxation rates of LLS can probe motions and interactions in biomolecules. LLS of the aliphatic protons of glycines, with lifetimes approximately four times longer than their spin–lattice relaxation times, are reported for the first time in an intrinsically disordered protein domain. LLS relaxation experiments were integrated with 2D spectroscopy methods, further adapting them for studies on proteins. Copyright © 2013 John Wiley & Sons, Ltd.

International audience ; New experiments are described for the determination of very slow diffusion constants by nuclear magnetic resonance (NMR) using long-lived (singlet) states. These experiments are suitable for molecules or conformations featuring a wide range of J-couplings.