Antioxidant and antitumor activity of trolox, trolox succinate, and α-tocopheryl succinate conjugates with nitroxides.

A possible ability of twelve new derivatives of known antioxidants trolox (TroH), trolox succinate (TroS), α-tocopheryl succinate (α-TOS) containing nitroxyl radicals (1-12) to protect bacterial cells from spontaneous and peroxide-induced mutagenesis and their cytotoxicity against six different tumor cells as well as two normal cells were investigated and compared with that for TroH, TroS, α-TOH, and α-TOS for the first time. In contrast to TroH and TroS, all nitroxide derivatives 1-12 demonstrated not only antioxidant properties, but also suppress the growth of human tumor cells: myeloma, mammary adenocarcinoma, hepatocarcinoma, T cells leukemia, histiocytic lymphoma, and T-cellular leucosis. The IC50 values (24 - ≥ 300 µM) depend significantly on the compounds and type of tumor cells. Some compounds were capable to inhibit the growth of normal mouse (LMTK) and hamster (AG17) fibroblast cells and demonstrate very different ratios in inhibition of various tumor and normal cell lines. Some nitroxide conjugates showed pronounced selectivity in suppressing the growth of several cancer cells. Overall, several compounds may be promising in parallel as antioxidants and as specific inhibitors of some tumor cells growth. Among considered spin labeled conjugates the most perspective derivatives as antioxidants and as antitumor agents are the compounds containing pyrrolidine nitroxides. In contrast to spin labeled TroH, TroS and α-TOS conjugates 1-12 succinyl derivatives 13-15 were inactive in inhibiting the growth of any tumor cells. It means that for suppressing the cancer cells the compounds should contain in their structures fragments of TroH, TroS or α-TOS.

Epidemiology of fracture in the Russian Federation and the development of a FRAX model.

UNLABELLED: The incidence of hip, forearm and humeral fractures was studied in two cities from the Russian Federation. Fracture rates were used to create a FRAX model for Russia and to estimate the current and future burden of fracture. PURPOSE: There is scant information on the epidemiology of fracture in Russia. The aim of the study was to determine the incidence of major fractures in order to populate a new FRAX model and to characterise the burden and future burden of fractures. METHODS: The number of hip, forearm and humeral fractures was determined in two Russian cities with a well-defined catchment population over a 2-3-year period. Incidence rates for the two cities were merged and used to populate a FRAX model for Russia. Incidence rates were also applied to the general population in 2010 and 25 years later in 2035. RESULTS: A total of 6,012 fractures were documented. For hip fracture, 27 % of cases in Pervouralsk and 1.8 % in Yaroslavl were not registered in the hospital data base. The incidence of index fractures increased with age and was higher in women than in men. The lifetime probability of hip fracture at the age of 50 years was 4 % in men and 7 % in women. The total number of hip fractures estimated in 2010 (112,000) is expected to rise to 159,000 in 2035. The estimated number of major fractures will rise from 590,000 to 730,000 over the same time interval. CONCLUSIONS: Fragility fractures pose a serious health care problem in Russia. Urgent steps are needed to improve the acute management of hip fracture and long-term care of other osteoporotic fractures.

Substrate specificity of rat sera IgG antibodies with peroxidase and oxidoreductase activities.

We have recently shown that intact IgGs from the sera of healthy Wistar rats oxidize 3,3'-diaminobenzidine (DAB) in the presence and in the absence of H(2)O(2) similar to horseradish peroxidase (HRP). Here we demonstrate for the first time that the peroxidase and oxidoreductase activities of IgGs can efficiently oxidize not only DAB but also o-phenylendiamine, phenol, p-dihydroquinone, alpha-naphthol, and NADH but, in contrast to HRP, cannot oxidize adrenalin. In contrast to IgGs, HRP cannot oxidize phenol, p-dihydroquinone, or alpha-naphthol in the absence of H(2)O(2). In contrast to plant and mammalian peroxidases, IgGs were more universal in their metal dependence. The specific wide repertoire of polyclonal peroxidase and oxidoreductase IgGs oxidizing various substances could play an important role in protecting the organism from oxidative stress and serve as an additional natural system destroying different toxic, carcinogenic, and mutagenic compounds.

Age-dependent increase of etheno-DNA-adducts in liver and brain of ROS overproducing OXYS rats.

Reactive oxygen species (ROS) and lipid peroxidation (LPO) play a role in aging and degenerative diseases. To correlate oxidative stress and LPO-derived DNA damage, we determined etheno-DNA-adducts in liver and brain from ROS overproducing OXYS rats in comparison with age-matched Wistar rats. Liver DNA samples from 3- and 15-month-old OXYS and Wistar rats were analyzed for 1,N6-ethenodeoxyadenosine (epsilondA) and 3,N4-ethenodeoxycytidine (epsilondC) by immunoaffinity/32P-postlabelling. While epsilondA and epsilondC levels were not different in young rats, adduct levels were significantly higher in old OXYS rats when compared to old Wistar or young OXYS rats. Frozen rat brain sections were analyzed for epsilondA by immunostaining of nuclei. Brains from old OXYS rats accumulated epsilondA more frequently than age-matched Wistar rats. Our results demonstrate increased LPO-induced DNA damage in organs of OXYS rats which correlates with their known shorter life-span and elevated frequency of chronic degenerative diseases.

Thermodynamic, kinetic, and structural basis for recognition and repair of 8-oxoguanine in DNA by Fpg protein from Escherichia coli.

X-ray analysis does not provide quantitative estimates of the relative importance of the molecular contacts it reveals or of the relative contributions of specific and nonspecific interactions to the total affinity of specific DNA to enzymes. Stepwise increase of DNA ligand complexity has been used to estimate the relative contributions of virtually every nucleotide unit of 8-oxoguanine-containing DNA to its total affinity for Escherichia coli 8-oxoguanine DNA glycosylase (Fpg protein). Fpg protein can interact with up to 13 nucleotide units or base pairs of single- and double-stranded ribo- and deoxyribo-oligonucleotides of different lengths and sequences through weak additive contacts with their internucleotide phosphate groups. Bindings of both single-stranded and double-stranded oligonucleotides follow similar algorithms, with additive contributions to the free energy of binding of the structural components (phosphate, sugar, and base). Thermodynamic models are provided for both specific and nonspecific DNA sequences with Fpg protein. Fpg protein interacts nonspecifically with virtually all of the base-pair units within its DNA-binding cleft: this provides approximately 7 orders of magnitude of affinity (Delta G degrees approximately equal to -9.8 kcal/mol) for DNA. In contrast, the relative contribution of the 8-oxoguanine unit of the substrate (Delta G degrees approximately equal to -0.90 kcal/mol) together with other specific interactions is <2 orders of magnitude (Delta G degrees approximately equal to -2.8 kcal/mol). Michaelis complex formation of Fpg protein with DNA containing 8-oxoguanine cannot of itself provide the major part of the enzyme specificity, which lies in the k(cat) term; the rate is increased by 6-8 orders of magnitude on going from nonspecific to specific oligodeoxynucleotides.