Biomedical subjects

Francesco Piva

Publications and source records attributed to Francesco Piva.

5 recordsLinked to original sources

PubMed2006

A possible regulatory role of 17beta-estradiol and tamoxifen on glyoxalase I and glyoxalase II genes expression in MCF7 and BT20 human breast cancer cells.

The glutathione-dependent glyoxalases system, composed of glyoxalase I (GloI) and glyoxalase II (GloII) enzymes, is involved in the detoxification of methylglyoxal, a by-product of cell metabolism. Aberrations in the expression of glyoxalase genes in several human cancers have been reported. Sometimes, these aberrations seem to differ depending on the organs and on the sensitivity of the tumours to estrogens, as we previously detected in the hormone-responsive breast cancer compared to the hormone-independent bladder cancer. To investigate a possible regulatory role of estrogens, as well as antiestrogens, on glyoxalases system, estrogen receptor (ER)-positive MCF7 and ER-negative BT20 human breast cancer cells were cultured in the presence of 17beta-estradiol (E2) and tamoxifen (TAM) performing two independent experiments. After a 24 h or 4 days treatment, we evaluated GloI and GloII mRNA levels, by Ribonuclease Protection Assay (RPA), enzymatic activities spectrophotometrically and cell proliferation by [3H]thymidine incorporation. We found that both steroid molecules affected glyoxalases gene expression and proliferation in a different manner in the cell lines. The modifications in mRNA levels were accompanied by parallel changes in the enzymatic activities. The possibility that modulation of glyoxalase genes by E2 and TAM are due to the presence of estrogen response elements (ERE) or cross-talk mechanisms by proteins of the estrogen signal transduction pathways are discussed. Knowledge regarding the regulation of glyoxalases by E2 and TAM may provide insights into the importance of this enzymes in human breast carcinomas in vivo.

Breast Neoplasms↗

PubMed2006

Use of the land snail Helix aspersa as sentinel organism for monitoring ecotoxicologic effects of urban pollution: an integrated approach.

Atmospheric pollution from vehicular traffic is a matter of growing interest, often leading to temporary restrictions in urban areas. Although guidelines indicate limits for several parameters, the real toxicologic impacts remain largely unexplored in field conditions. In this study our aim was to validate an ecotoxicologic approach to evaluate both bioaccumulation and toxicologic effects caused by airborne pollutants. Specimens of the land snail Helix aspersa were caged in five sites in the urban area of Ancona, Italy. After 4 weeks, trace metals (cadmium, chromium, copper, iron, manganese, nickel, lead, and zinc) and polycyclic aromatic hydrocarbons (PAHs) were measured and these data integrated with the analyses of molecular and biochemical responses. Such biomarkers reflected the induction of detoxification pathways or the onset of cellular toxicity caused by pollutants. Biomarkers that correlated with contaminant accumulation included levels of metallothioneins, activity of biotransformation enzymes (ethoxyresorufin O-deethylase, ethoxycoumarin O-deethylase), and peroxisomal proliferation. More general responses were investigated as oxidative stress variations, including efficiency of antioxidant defenses (catalase, glutathione reductase, glutathione S-transferases, glutathione peroxidases, and total glutathione) and total oxyradical scavenging capacity toward peroxyl and hydroxyl radicals, onset of cellular damages (i.e., lysosomal destabilization), and loss of DNA integrity. Results revealed a marked accumulation of metals and PAHs in digestive tissues of organisms maintained in more traffic-congested sites. The contemporary appearance of several alterations confirmed the cellular reactivity of these chemicals with toxicologic effects of potential concern for human health. The overall results of this exploratory study suggest the utility of H. aspersa as a sentinel organism for biomonitoring the biologic impact of atmospheric pollution in urban areas. Key words: atmospheric pollutants, bioindicators, biomarkers, DNA integrity, lysosomes, metallothioneins, oxidative stress, peroxisomes, polycyclic aromatic hydrocarbons, trace metals.

Air Pollutants↗

PubMed2006

RANDNA: a random DNA sequence generator.

Monte Carlo simulations are useful to verify the significance of data. Genomic regularities, such as the nucleotide correlations or the not uniform distribution of the motifs throughout genomic or mature mRNA sequences, exist and their significance can be checked by means of the Monte Carlo test. The test needs good quality random sequences in order to work, moreover they should have the same nucleotide distribution as the sequences in which the regularities have been found. Random DNA sequences are also useful to estimate the background score of an alignment, that is a threshold below which the resulting score is merely due to chance. We have developed RANDNA, a free software which allows to produce random DNA or RNA sequences setting both their length and the percentage of nucleotide composition. Sequences having the same nucleotide distribution of exonic, intronic or intergenic sequences can be generated. Its graphic interface makes it possible to easily set the parameters that characterize the sequences being produced and saved in a text format file. The pseudo-random number generator function of Borland Delphi 6 is used, since it guarantees a good randomness, a long cycle length and a high speed. We have checked the quality of sequences generated by the software, by means of well-known tests, both by themselves and versus genuine random sequences. We show the good quality of the generated sequences. The software, complete with examples and documentation, is freely available to users from: http://www.introni.it/en/software.

Base Sequence↗

PubMed2005

Pro-oxidant effects of extremely low frequency electromagnetic fields in the land snail Helix aspersa.

Pro-oxidant effects of extremely low frequency (ELF) 50-Hz magnetic fields were investigated in the land snail Helix aspersa exposed both in short-term laboratory treatments and under field conditions by maintaining the organisms in the proximity of a power line for up to 2 months. Oxidative perturbations were investigated as individual antioxidants (catalase, glutathione reductase, glutathione S-transferases, and total glutathione) and total scavenging capacity toward peroxyl radicals and hydroxyl radicals. Accumulation of lipid peroxidation products, destabilization of lysosomal membranes, and loss of DNA integrity were also evaluated as markers of cell damage. The overall results indicated an oxidative challenge caused by ELF magnetic fields with particularly prompt and sensitive responses for catalase, glutathione reductase, and the overall capability to neutralize peroxyl radicals. Cell injuries occurred to different extents according to duration and intensity of electromagnetic exposure and confirmed complex cause-effect relationships between pro-oxidant factors, efficiency of antioxidant defenses, and the onset of oxidative toxicity. This study highlights the importance of a multimarker approach for detecting a wide panel of biological responses, the necessity of investigating the long-term effects of early oxidative responses, and the role of ELF in enhancing susceptibility to other forms of pathologies or diseases.

Animals↗

PubMed2005

Correlation Finder.

Correlation Finder is a free software which allows to seek exhaustively correlations between nucleotides in genomic sequences. It permits to analyze generic DNA sequences and genic sequences where the codon phase needs to be taken into account. Its graphic interface allows to easily set the parameters that characterize the motifs being sought. This tool handles large data sets and runs on the Windows operative system.

Codon↗