[en] Among 51 Δ³-chromens substituted by an electro-attractive group at the 3-position, 23 have confirmed radioprotecting properties. Most of them are acetylated or formylated of even nitrated derivatives

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[en] A reivew of the problems and progress in the field of chemical radioprotection is given. After defining the field of research, the practical significance of radioprotective substances and the requirements for a utilizable radioprotective preparation are presented. Trends of development of this field of research, the state of the art, and resulting conclusions for the future development of radioprotective substances of practical value are discussed. (author)

[en] The efficacy of radioprotector WR-2721 (300 mg/kg ip, 20 min before irradiation), alone or in combination with an extract of Ginkgo biloba (Tebonin^R) (17.5 mg/kg ip, 20 min before, and then 1 hr and 24 hr after irradiation), an extract of thymus (Thymolip^R) (10 mg/kg sc, 24 hr before and 15 min after irradiation), herbal mitogen agrostemin (0.1 mg/kg ip. 24 before and immediately after irradiation) and calcium antagonist verapamil (1 mg/kg ip, immediately before irradiation), was studied in adult male Wistar rats irradiated by 9 Gy and 12 Gy of X-rays. It was established that above mentioned compounds, except wr-2721, failed to protect irradiated animals. Given in combination with WR-2721 only agrostemin and verapamil enhanced the efficacy of the protector. The combination with verapamil was more effective providing protection even in supralethal irradiated rats. (author)

[en] Since discovery, between 1951 and 1955, of the classical radioprotective agents cysteamine, serotonin and A.E.T., synthesis of more active molecules, long acting polymers and compounds active when orally administered, have been performed, especially during the last decade. On the other hand, extensive investigations on mechanism of action of radioprotective agents and particularly discovery of the essential role displayed by protection of the central nervous system of mammals allowed a marked improvement of concepts in the field of chemical radioprotection

[en] An analysis is made of data on the toxicity of radiation protective substances produced in various Soviet and foreign laboratories. (V.A.P.)

[en] Programmed cell death (PCD) is essential for development and homeostasis of multicellular organisms and can occur by caspase-dependent apoptosis or alternatively, by caspase-independent PCD (ciPCD). Bcl-2, a central regulator of apoptosis, localizes to both mitochondria and the endoplasmic reticulum (ER). Whereas a function of mitochondrial and ER-specific Bcl-2 in apoptosis has been established in multiple studies, corresponding data for ciPCD do not exist. We utilized Bcl-2 constructs specifically localizing to mitochondria (Bcl-2 ActA), the ER (Bcl-2 cb5), both (Bcl-2 WT) or the cytosol/nucleus (Bcl-2 ΔTM) and determined their protective effect on ceramide-mediated ciPCD in transiently and stably transfected Jurkat cells. Expression of the constructs was verified by immunoblots. Ceramide-mediated ciPCD was induced by treatment with human recombinant tumor necrosis factor and determined by flow cytometric measurement of propidium iodide uptake as well as by optical analysis of cell morphology. Only wildtype Bcl-2 had the ability to efficiently protect from ceramide-mediated ciPCD, whereas expression of Bcl-2 solely at mitochondria, the ER, or the cytosol/nucleus did not prevent ceramide-mediated ciPCD. Our data suggest a combined requirement for both mitochondria and the ER in the induction and the signaling pathways of ciPCD mediated by ceramide

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