Chick embryos have been used as alternative experimental animals in various research fields, including virology, immunology, toxicology, oncology, and embryology. Until now, there have been no in vivo models using chick embryo to evaluate radiosensitizing activity. Here, the in vivo radiosensitizing activity of etanidazole, a well-known hypoxic cell radiosensitizer, was evaluated using tumor-be...

A class of radiosensitizers is discussed which irreversibly inhibits the repair of x-ray-induced single-strand breaks in DNA. Such agents are active when added after irradiation and potentiate x-ray-induced killing in rec + strains of E. coli K-12, but have little effect on the viability of x-irradiated recA strains which are deficient in their ability to repair x-ray-induced single-strand brea...

Four different nitroimidazole derivatives, with up to two iodine atoms on the imidazole ring, were investigated for their radiosensitizing potency under hypoxic conditions, in order to test whether the introduction of iodine atoms increases the radiosensitizing potency of nitroimidazoles. Misonidazole and metronidazole were used as controls. Human colonic adenocarcinoma cells were incubated wit...

The interaction of hyperthermia (41--45 degrees C) and chemotherapeutic agents frequently results in increased cytotoxicity over that predicted for an additive effect, although to date only a very limited number of drugs have been examined for such a possible interaction. At 42 degrees C, the upper limit of temperature useful for whole-body hyperthermia, the most promising agents of those exami...

This review focuses on the recent development of hypoxia-activated cytotoxins. Such drugs are prodrugs activated to cytotoxic products in the hypoxic environment of solid tumors (so-called "bioreductive prodrugs"), but can also be activated by radiation (radiation-activated prodrugs). These compounds grew out of research on hypoxic radiosensitizers, which are compounds that can overcome the rad...

Sulfonamides and quinoxaline derivatives possess many types of biological activities and have been recently reported to show substantial antitumor activity. This paper reports the synthesis of novel thioureido sulfaquinoxaline derivatives. All the newly synthesized compounds were evaluated for their in vitro anticancer activity against a human liver cell line (HEPG2) and showed higher activity ...

-Bilateral kidney ligation of mice immediately before injection of misonidazole (MIS) prolongs the plasma half-life of this radiosensitizer from about 2 h (in normal mice) to 10-11 h, similar to that in man. Kidney ligation does not, however, change the relative proportions of MIS and its 0-demethylated metabolite, Ro-05-9963, for the first 12 h after MIS injection. Kidney ligation was used wit...

The effect of elevated temperature (44 degrees) on the intracellular uptake of the 2-nitroimidazole hypoxic cell radiosensitizer, misonidazole (MIS), and analogues more hydrophilic than MIS was studied in Chinese hamster ovary cells. It was found that the intracellular uptake of these compounds which enter cells by restricted passive diffusion can be enhanced approximately 4-fold when incubated...

Radiosensitizers can increase local treatment efficacy under a relatively low and safe radiation dose, thereby facilitating tumor eradication and minimizing side effects. Here, a new class of radiosensitizers is reported, which contain several gold (Au) atoms embedded inside a peptide shell (e.g., Au10-12 (SG)10-12 ) and can achieve ultrahigh tumor uptake (10.86 SUV at 24 h post injection) and ...

Low-energy electrons (LEEs) at energies of less than 2 eV effectively decompose 4-nitroimidazole (4NI) by dissociative electron attachment (DEA). The reactions include simple bond cleavages but also complex reactions involving multiple bond cleavages and formation of new molecules. Both simple and complex reactions are associated with pronounced sharp features in the anionic yields, which are i...