Biomedical subjects

F Regoli

Publications and source records attributed to F Regoli.

At least 37 records · Page 2Linked to original sources

PubMed1998

Metallothioneins in Arctic bivalves.

In the framework of an International Association for the Promotion of Cooperation with Scientists from the Independent States of the Former Soviet Union (INTAS) Project on biodiversity and adaptation strategies of Arctic coastal marine benthos, research was focused on the role of metallothioneins as a possible indicator of the effect on animals and availability of trace metals in the Arctic. Metallothioneins are low-molecular-weight, cysteine-rich proteins known to be induced by high environmental levels of trace metals. Specimens of Macoma balthica and Mytilus edulis were collected along several Arctic estuaries in the White and Pechora seas; whole tissues for M. balthica and the digestive gland and gills for M. edulis were dissected, frozen in liquid nitrogen, and lyophilized onboard. Metallothionein concentrations were determined by a polarographic assay. From the same stations organisms and sediments were also collected for metal analysis. The results revealed significant differences in metallothionein concentrations among the stations for M. balthica. Similar, although less marked, differences were also obtained in the organs of M. edulis. Data on metallothionein were compared with trace metal concentrations in both the organisms and sediments. Also, the relationship with abiotic factors (salinity) and biological variables (size of sampled organisms) was determined. In particular, biological variables seemed to influence metallothionein concentration in the organisms and their effect should be carefully considered for a correct assessment of differences between stations.

Animals↗

PubMed1998

Trace metals and antioxidant enzymes in gills and digestive gland of the Mediterranean mussel Mytilus galloprovincialis.

A seasonal variability of trace metal concentrations and antioxidant enzymes was observed in gills and digestive gland of the Mediterranean mussel Mytilus galloprovincialis from both a polluted and a nonpolluted population. Trace metals (As, Cu, Fe, Mn, Pb, and Zn) exhibited, in both organs, maximum values in later winter-early spring followed by a progressive decrease during the summer. While in the gills this behavior probably reflects a different bioavailability of metals, in the digestive gland it is influenced mainly by the progressive infiltration of the organ by gonadic tissues during gametogenesis. Metals, as other pollutants, are known to influence the oxidative status of these organisms and antioxidant enzymes have been often proposed as biomarkers of exposure to contaminants. In this respect, it was of interest to compare the variations of these biochemical parameters with those of metal levels in two mussel populations from a polluted and a nonpolluted site, respectively. The biochemical parameters examined included the level of glutathione and the activity of the following glutathione dependent and antioxidant enzymes: glyoxalase I, EC 4.4.1.5; glyoxalase II, EC3.1.2.6; glutathione S-transferases, EC 2.5.1.18; glutathione reductase, EC 1.6.4.2; Se-dependent, EC 1.11.1.9 and Se-independent, EC 2.5.1.18 glutathione peroxidases; catalase, EC 1. 11.1.6; superoxide dismutase, EC 1.15.1.1. Seasonal variations of trace metals did not appear to influence those of biochemical parameters, which generally showed an opposite trend with higher enzymatic activities in summer when trace metal concentrations were lower. The effects of metals on antioxidant enzymes were more evident when the two mussel populations were compared. In particular, organisms from the polluted site showed lower levels of glutathione and higher enzymatic activities of glyoxalase I even though the magnitude of these differences was not constant during the year. Moreover, native mussels from both the polluted and control populations exhibited limited differences in the activities of glutathione reductase, glutathione peroxidases, catalase, and superoxide dismutase, suggesting the possibility of some biochemical adaptation in organisms from chronically polluted environments.

Animals↗

PubMed1998

Trace metals and variations of antioxidant enzymes in Arctic bivalve populations.

In the framework of an INTAS project, arctic populations of the clam Macoma balthica were collected from seven stations (Mezen, Khaypudyr, Pechora 3, Pechora 5, Dvina, Keret 1, and Keret 2) in the White Sea and Pechora Sea. The main objectives of this research were to define baseline concentrations of trace metals (As, Cd, Cr, Cu, Fe, Mn, Pb, Zn) in M. balthica and to evaluate antioxidant responses as biomarkers of anthropogenic stress in these organisms. The antioxidant parameters examined included the levels of glutathione and the activities of several glutathione-dependent and antioxidant enzymes: glyoxalase I and glyoxalase II (EC 4.4.1.5 and EC 3.1.2.6), glutathione S-transferases (EC 2.5.1.18), glutathione reductase (EC 1.6.4.2), glutathione peroxidases (EC1.11.1.9 and EC 2.5.1.18, respectively, for Se-dependent and Se-independent forms), superoxide dismutase (SOD, EC 1.15.1.1), and catalase (EC 1.11.1.6). Organisms revealed enhanced concentrations of lead in both Keret stations, Khaypudyr, and Mezen, and high levels of copper in Keret and cadmium in Khaypudyr. At the biochemical level, organisms from Pechora 3, Pechora 5, and Dvina were not statistically different, whereas those from Mezen and Khaypudyr exhibited higher activities of superoxide dismutase, glutathione peroxidase, and glyoxalase II. Catalase levels were lower in Mezen and Khaypudyr. More heterogeneous were the responses of glyoxalase I and glutathione S-transferases, while no significant differences among the stations were observed for glutathione reductase. Multiple regression analyses revealed significant positive relationships between the main antioxidant enzymes (glutathione peroxidases, superoxide dismutase, glyoxalase I, and glyoxalase II), and confirmed the exception of catalase, which, when significant, was negatively correlated with the other parameters. The results support the suitability of antioxidant responses as biomarkers of pollutant exposure and/or toxicity for arctic biomonitoring programs even though only moderately polluted sites were sampled.

Alkyl and Aryl Transferases↗

PubMed1998

A rapid gas chromatographic assay for determining oxyradical scavenging capacity of antioxidants and biological fluids.

Herein, we report a new, rapid,and reliable method for measuring the protective antioxidant potential of pure antioxidant solutions or biological tissues. Peroxyl radicals generated by thermal homolysis of 2,2'-azobis-amidinopropane (ABAP) cause the oxidation of alpha-keto-gamma-methiolbutyric acid (KMBA) to ethylene; ethylene formation is monitored by gas chromatographic analysis of head space from the reaction vessel. The partial inhibition of ethylene formation in the presence of antioxidants that compete with KMBA for oxyradicals is the basis of the Total Oxyradical Scavenging Capacity Assay (TOSCA). The assay is shown to be reliable for quantifying ROS scavenging potential. The quantifiable parameters are consistent with the relative order of those predicted by the fluorescence- and oxygen electrode-based assays reported in the literature. Antioxidants competing for peroxyl radicals influenced the rate of KMBA oxidation in different ways, but the calculation of TOSC was not affected by such variations. Responses were linear over a wide range of sample concentrations and the TOSC values of classical soluble antioxidants showed the following relative order: Trolox > uric acid > ascorbic acid > GSH. The KMBA method was reliable for biological tissues; the TOSC for 1 microg rat liver cytosolic protein was 0.40 +/- 0.02 and for the microsomal membrane, 0.15 +/- 0.03. Soluble antioxidants accounted for 77% of the protective antioxidant potential in rat liver cytosol. When incorporated into the microsomal membrane, alpha-tocopherol markedly enhances antioxidant protection against peroxyl radical; thus, the assay is suitable for the assessment of fat-soluble antioxidants.

Animals↗

PubMed1994

Seasonal variation of trace metal concentrations in the digestive gland of the Mediterranean mussel Mytilus galloprovincialis: comparison between a polluted and a non-polluted site.

Seasonal changes in metal (Cu, Fe, Mn, Pb, and Zn) concentrations were observed in the digestive gland of the Mediterranean mussel, Mytilus galloprovincialis, from both a polluted and a non-polluted population. Digestive gland of mussels from the polluted site showed metal concentrations appreciably higher than in non-polluted organisms, especially for Pb (up to 160 micrograms/g d.w.), Mn (up to 300 micrograms/g d.w.), and Fe (up to 8,500 micrograms/g d.w.), whereas the two populations showed maximum mean values, respectively, of 34 and 20 micrograms/g d.w. for Cu and 170 and 120 micrograms/g d.w. for Zn. Over 1 year (1991), differences between maximum and minimum values were moderate only in the unpolluted organisms. During gametogenesis, while the metal concentrations (expressed as microgram/g dry weight) decreased in the digestive gland, the tissue burden (as microgram) in that organ remained nearly constant or increased slightly. The apparent decrease in metal concentrations was probably due to the penetration of gonadic tissues into the digestive gland during gametogenesis, which biologically diluted metal concentrations in mussels from both the polluted and unpolluted populations. The effect of mussel size on trace metal concentrations in the digestive gland was demonstrated during different stages of the reproductive cycle. Higher concentrations were found in smaller organisms; however, during the spawning period, due to the fact that this is not a synchronous process within a population, the organisms exhibit a high variability in digestive gland weight which can mask this relationship when digestive gland weight is used as a size-index and as a parameter of the trace metal digestive gland burden.

Animals↗

PubMed1994

Bioavailability of biologically detoxified lead: risks arising from consumption of polluted mussels.

The possible risk for human health arising from consumption of lead-polluted shellfish was suggested by experiments on the bioavailability for mice of a "biologically detoxified" form of the metal. In this work, young mice were fed with a mixed diet including mussels collected in a Pb-polluted area. Metal concentrations in blood, kidney, liver, urine, and feces and the activity of erythrocytic delta-aminolevulinic acid dehydratase were determined after 1, 2, and 4 weeks. Comparisons were made with mice treated with balanced diet, mixed diet including control mussels, and drinking water with lead dissolved as acetate. In mice fed polluted mussels, lead concentrations increased in blood, kidney, and liver, whereas no significant accumulation was observed in urine. Different responses in mice treated with Pb(CH3COO)2 in drinking water are probably due to the diversity of lead chemical form in the two treatments. Our results demonstrate the bioavailability of biologically detoxified lead that can be transferred to a consumer with possible consequences also for human health.

Animals↗

PubMed1982