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Inefficient response to oxidative stress has been associated with ageing and health risk. Metals are known to inhibit DNA repair and may modify the antioxidant response. How genetic variability and lifestyle factors modulate the response to oxidative stress is poorly explored. Our study aims to disentangle the contribution of genetics and environmental exposures to oxidative stress response using data from twin pairs. The non-enzymatic antioxidant capacity (NEAC), the repair capacity of 8-oxo-7,8-dihydroguanine (OGG activity) and the levels of 12 metals were measured in blood of 64 monozygotic and 31 dizygotic twin pairs. The contributions of genetic and environmental effects were assessed using standard univariate twin modelling. NEAC and OGG activity significantly decreased with age. Gender-, age- and body mass index-associated differences were identified for some metals. Principal Component Analysis identified two groups of metals whose levels in blood were highly correlated: As, Hg, Pb, Se, Zn and Al, Co, Cr, Mn, Ni. The environmental influence was predominant on OGG activity and NEAC variance whereas for most metals the best-fitting model incorporated additive genetic and unique environmental sources of variance. NEAC and OGG activity were both inversely correlated with blood levels of various metals. The inhibition of OGG activity by Cd was largely explained by smoking. Our data show a substantial role of environmental factors in NEAC and OGG activity variance that is not explained by twins' age. Exogenous environmental factors such as metals contribute to oxidative stress by decreasing NEAC and inhibiting repair of oxidatively-induced DNA damage., (Copyright © 2016 Elsevier Inc. All rights reserved.)

8-Oxoguanine DNA glycosylase (OGG) activity was measured by an in vitro assay in lymphocytes of healthy volunteers genotyped for various OGG1 polymorphisms. Only homozygous carriers of the polymorphic C326 allele showed a significantly lower OGG activity compared to the homozygous S326 genotype. The purified S326C OGG1 showed a decreased ability to complete the repair synthesis step in a base excision repair reaction reconstituted in vitro. The propensity of this variant to dimerize as well as its catalytic impairment were shown to be enhanced under oxidizing conditions. Mass spectrometry revealed that the extra cysteine of the variant protein is involved in disulfide bonds compatible with significant conformational changes and/or dimerization. We propose that the S326C OGG1 catalytic impairment and its susceptibility to dimerization and disulfide bond formation in an oxidizing environment all concur to decrease repair capacity. Consequently, the C326 homozygous carriers may be at increased risk of oxidative pathologies., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Within the framework of research carried out by our team aimed at developing new immunological methods to determine proteins such as immunoglobulins G in different biological matrixes, for instance, serum and milk, tests were performed on several immunosensors based on different transducer types, i.e. amperometric (classical or screen-printed) electrodes for hydrogen peroxide. Lastly the feasibility of constructing immunosensors based on surface plasmon resonance (SPR) was investigated. "Competitive" immunological procedures were used in the first two cases. Conversely, the surface plasmon resonance transduction technique allowed a "direct" measurement. Applications were performed on human serum, powdered milks for babies and particularly on several animal milks, in the case of buffalo milk seeking a routine control method to identify possible inflammatory affections in the animals., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Organic nitrates, such as glyceryltrinitrate, are nitric oxide (NO) donor drugs that engender tolerance with long-term use. Here, we tested the hypothesis that our novel S-nitrosothiols, N-(S-nitroso-N-acetylpenicillamine)-2-amino-2-deoxy-1,3,4,6, tetra-O-acetyl-beta-D-glucopyranose (RIG200) and S-nitroso-N-valeryl-D-penicillamine (D-SNVP), do not induce vascular tolerance ex vivo. Femoral arteries from adult male Wistar rats were preconstricted with phenylephrine and perfused with the NO synthase inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME). Perfusion pressure was measured during 20 h treatment with supramaximal concentrations of NO donor (10 microM). Perfusion with glyceryltrinitrate caused a vasodilatation, which recovered over 2-20 h. In contrast, the S-nitrosothiols caused vasodilatations that were maintained throughout the 20 h perfusion period. Responses to S-nitrosothiols were partially reversed by the NO scavenger ferrohaemoglobin and fully reversed by the soluble guanylate cyclase inhibitor [1H-[1,2,4] oxadiazole [4,3-a]quinoxaline-1-one (ODQ). Glyceryltrinitrate-tolerant vessels were fully responsive to bolus injections of S-nitrosothiols. Resistance to tolerance is an attractive property of our novel compounds, particularly in view of their sustained activity in arteries with damaged endothelium.

Organic nitrates, such as glyceryl trinitrate, are nitric oxide (NO) donor drugs that engender tolerance with long-term use. Here, we tested the hypothesis that our novel S-nitrosothiols, N-(S-nitroso-N-acetylpenicillamine)-2-amino-2-deoxy-1,3,4,6, tetra-O-acetyl-beta-D-glucopyranose (RIG200) and S-nitroso-N-valeryl-D-penicillamine (D-SNVP), do not induce vascular tolerance ex vivo. Femoral arteries from adult male Wistar rats were preconstricted with phenylephrine and perfused with the NO synthase inhibitor N(omega)-nitro-L-arginine methyl ester (L-NAME). Perfusion pressure was measured during 20-h treatment with supramaximal concentrations of NO donor (10 microM). Perfusion with glyceryltrinitrate caused a vasodilatation, which recovered over 2-20 h. In contrast, the S-nitrosothiols caused vasodilatations that were maintained throughout the 20-h perfusion period. Responses to S-nitrosothiols were partially reversed by the NO scavenger ferrohaemoglobin and fully reversed by the soluble guanylate cyclase inhibitor [1H-[1,2,4] oxadiazole [4,3-a]quinoxaline-1-one (ODQ). Glyceryltrinitrate-tolerant vessels were fully responsive to bolus injections of S-nitrosothiols. Resistance to tolerance is an attractive property of our novel compounds, particularly in view of their sustained activity in arteries with damaged endothelium.

An amperometric biosensor for the direct determination of L-glutamate was developed by chemical bonding of L-glutamate oxidase (GAO) on a carboxylic Nylon membrane with polyazetidine prepolymer (PAP), and using a hydrogen peroxide electrode as indicating sensor. The biosensor is specific for L-glutamate and the peculiar analytical properties (linearity range, reproducibility, accuracy) were experimentally determined. Furthermore, the same basic biosensor was also modified to be used and characterized for the direct determination of L-glutamine. This L-glutamine biosensor was obtained by coimmobilizing, on two separate membranes, glutamic acid oxidase and glutaminase (GMN) on the same biosensor. The two sensors were then used for the determination of glutamate and L-glutamine contained in pharmaceutical formulations and the results were compared with those obtained by other analytical methods.

A suitable biosensor for the analysis of inorganic phosphate was developed by coupling the enzyme glucose oxidase to a slice of potato (Solanum tuberosum) containing the acid phosphatase, and using an amperometric Clark electrode as an indicating sensor. Phosphate concentration can be determined from its inhibition on the acid phosphatase activity. Measurements were carried out at steady-state conditions and the available concentration range of phosphate, repeatability and accuracy, on phosphate standard solutions, were experimentally determined. Finally the sensor was used in pharmaceutical and biological matrices. The results were compared with those ones obtained by Bartlett's spectrometric method.

A PVC (polyvinychloride) ion selective electrode, employing benzyldimethyl-cetylammoniumbenzylpenicillin as sensor, was prepared, characterized and applied to the analysis of commercially available formulations containing benzylpenicillin and other antibiotics of the penicillin or cephalosporin group. The results are compared with those obtained by using the corresponding liquid membrane electrode.

1. The molecular weights of the two major rRNA species (L-rRNA, large ribosomal subunit RNA, and S-rRNA, small ribosomal subunit RNA) of a variety of deuterostomia, green plants and fungi have been investigated by gel electrophoresis in 99% formamide, pH 9; the overall pattern obtained under these conditions differs to some extent from that deduced by electrophoresis in neutral-salt solutions. 2. The molecular weights of the deuterostomian S-rRNA species have been conserved at a value of 0.65 X 10(6), whereas those of the L-rRNA have been kept at 1.40 X 10(6) in the lower species but have increased to 1.55 X 10(6) in birds and to 1.65 X 10(6) in mammals. 3. The molecular weights of the L-rRNA and S-rRNA components of the green plants (Dycotyledons, Monocotyledons and Gymnosperms) have been generally conserved at 1.30 X 10(6) and 0.65 X 10(6). 4. The molecular weight of the L-rRNA of the fungi has been conserved at 1.36-1.38 X 10(6), being 0.1 X 10(6) daltons heavier than that of the plants; the S-rRNA exhibits a limited degree of variability, ranging between 0.65 X 10(6) and 0.72 X 10(6).

Two new polymeric membrane electrodes selective to cholate and to benzylpenicillinate, based respectively on PVC membranes containing polybenzyl-propargilamine as conductor polymer and benzyldimethylcethylammonium-cholate, or -benzylpenicillinate as exchangers, have been prepared, and applied to the determination of cholic acids, anionic surfactants and antibiotics. Results are compared with those ones obtained by analogous PVC sensors and liquid membrane sensors, previously described.

1. The molecular weights and the integrity of the principal rRNA species derived from the large and small ribosomal subunit (respectively, L-rRNA and S-rRNA) of several species of Protostomia and Protozoa have been investigated. 2. Using gel electrophoresis in formamide, the molecular weights of protostomian L-rRNA species have been found to range from 1.30 X 10(6) (Annelida) to 1.61 X 10(6) (Diptera); those of the S-rRNA's cover the range 0.65 X 10(6) (Annelida)-0.81 X 10(6) (Diptera). 3. Both rRNA components have incurred extensive changes among the Protozoa; the L-rRNA ranges in weight from 1.35 X 10(6) (T. pyriformis) to 1.57 X 10(6) (A. castellanii) and the S-rRNA from 0.70 X 10(6) of T. pyriformis to 0.85 X 10(6) of A. castellanii and E. gracilis. 4. The L-rRNA components of all the species investigated are discontinuous molecules endowed with a latent median break; depending on whether the nick is located at the centre of the L-rRNA chain, or lies off-centre, the molecular weight of the S-rRNA equals that of either both, or only one, of the two fragments composing the L-rRNA.