Response Patterns of Biomarkers as Tools to Identify Toxic Effects of Cadmium and Lead on Bufo gargarizans Embryo.

Molecular biomarkers play an increasing crucial role in evaluating and predicting toxicity of metals. Expressions patterns of genes related to oxidative stress, apoptosis, immune and inflammation response in the Bufo gargarizans embryo exhibited a development dependent manner. The genes related to oxidative stress (HSP, GPx and SOD) are the first response in the development of embryo, followed by the apoptosis (Bax, BCLAF1 and TRAIL) and inflammation and immune response (SOCS3, IL-27 and IL-17D), respectively. Then, we have verified the HSP, Bax and SOCS3 IL-27 (expressed highest in their respective processes) exhibited the most significant changes in Cd-Pb mixed group compared with control. In addition, we found exposure of Cd-Pb mixed metals causes greater adverse effects than Cd, Pb alone on development and morphology of embryo. Overall, our results provide a useful tool to use the sensitive molecular biomarkers as indicators of developmental toxicity in amphibian embryo.

Electron-Mediated Aminyl and Iminyl Radicals from C5 Azido-Modified Pyrimidine Nucleosides Augment Radiation Damage to Cancer Cells.

Two classes of azido-modified pyrimidine nucleosides were synthesized as potential radiosensitizers; one class is 5-azidomethyl-2'-deoxyuridine (AmdU) and cytidine (AmdC), while the second class is 5-(1-azidovinyl)-2'-deoxyuridine (AvdU) and cytidine (AvdC). The addition of radiation-produced electrons to C5-azido nucleosides leads to the formation of π-aminyl radicals followed by facile conversion to σ-iminyl radicals either via a bimolecular reaction involving intermediate α-azidoalkyl radicals in AmdU/AmdC or by tautomerization in AvdU/AvdC. AmdU demonstrates effective radiosensitization in EMT6 tumor cells.

Antiviral and Cytostatic Evaluation of 5-(1-Halo-2-sulfonylvinyl)- and 5-(2-Furyl)uracil Nucleosides.

Transition metal-catalyzed halosulfonylation of 5-ethynyl uracil nucleosides provided (E)-5-(1-chloro-2-tosylvinyl)uridines. Tetrabutylammonium fluoride-mediated direct CH arylation of 5-iodouracil nucleosides with furan or 2-heptylfuran gave 5-furyl-substituted nucleosides without the necessity of using the organometallic substrates. These two classes of 5-substituted uracil nucleosides as well their corresponding ester derivatives were tested against a broad range of DNA and RNA viruses and the human immunodeficiency virus (HIV). The 3',5'-di-O-acetyl-5-(E)-(1-chloro-2-tosylvinyl)-2'-deoxyuridine (24) inhibited the growth of L1210, CEM and HeLa cancer cells in the lower micromolar range. The (ß-chloro)vinyl sulfone 24 and 5-(5-heptylfur-2-yl)-2'-deoxyuridine (10) displayed micromolar activity against varicella zoster virus (VZV). The 5-(5-heptylfur-2-yl) analog 10 and its 3',5'-di-O-acetyl-protected derivative showed similar activity against the cytomegalovirus (CMV). The 5-(fur-2-yl) derivatives of 2'-deoxyuridine and arabino-uridine inhibited the replication of herpes simplex virus (HSV) TK+ strains while the 5-(5-heptylfur-2-yl) derivative 10 displayed antiviral activity against the parainfluenza virus.