Biomedical subjects

G Folesani

Publications and source records attributed to G Folesani.

6 recordsLinked to original sources

PubMed2006

Antagonistic effects of methyl-mercury and PCB153 on PC12 cells after a combined and simultaneous exposure.

The study of interactions for those substances which tend to accumulate in food and affect the nervous system appears to be a fundamental point to characterize the combined exposure in vitro. In this study we included two food contaminants which are known neurotoxicants: methyl-mercury (Me-Hg) and the ortho-substituted PCB 153. PC12 cells were treated with Me-Hg (range 1e-7, 2e-6 M) and PCB153 (range 1e-5, 4e-4 M) in single and combined synchronous experiments and a mathematical model was set up according to the Loewe additivity criterion to evaluate the level of interaction between toxicants, using viability as end-point. At some concentrations (Me-Hg 5e-7 M and PCB153 1e-4 and 2e-4 M; Me-Hg 1e-6M and PCB153 5e-5 M; Me-Hg 1e-7 M and PCB153 4e-4 M), a statistically significant antagonist effect was observed. No interaction was observed for other combinations. The analysis of other toxicological parameters known to be modified in single exposure experiments (TBARS and intra-cellular dopamine) confirmed the viability results. The results of our work represent a starting point to generate novel information on the interactions between PCB153 and Me-Hg in vitro, as well as a new relevant experimental and mathematical approach useful to investigate the effects of different toxicant mixtures.

Animals↗

PubMed2005

Acid-base equilibrium in exhaled breath condensate of allergic asthmatic children.

BACKGROUND: The dysregulation of airway pH control may have a role in asthma pathophysiology. The measurement of exhaled breath condensate (EBC) pH and ammonia levels may be used as a noninvasive method to study acid-base status in the airway of asthmatics. METHODS: Exhaled breath condensate from 29 allergic stable asthmatic children and 13 healthy controls was collected by cooling exhaled air during tidal breathing. Ammonia was measured by high-performance liquid chromatography with fluorescence detection. pH was measured after deaeration of EBC samples by bubbling with argon. The children also underwent FENO measurement. RESULTS: Both pH and ammonia values in EBC were significantly lower in the asthmatics than in the control group [pH: ICS-treated (median and interquartile range) 7.70 (7.62-7.74), steroid-naive 7.53 (7.41-7.68), controls 7.85 (7.80-7.90), P <0.01 and P <0.001, respectively; ammonia: ICS-treated 476.17 microM (282.50-594.80), steroid-naive 253.24 microM (173.43-416.08), controls 788.30 microM (587.29-1310.39), P < 0.05 and P <0.001, respectively]. Both pH and ammonia values were higher in ICS-treated than in steroid-naive asthmatic children. There was a significant correlation between EBC pH and ammonia concentrations. CONCLUSIONS: These data show that EBC pH values of stable asthmatic children are lower compared with those of healthy controls and positively correlated with ammonia concentrations, supporting the hypothesis that airway acidification may have a role in the pathobiology of allergic asthma.

Acid-Base Equilibrium↗

PubMed2001

Chiral separation of amino acids by copper(II) complexes of tetradentate diaminodiamido-type ligands added to the eluent in reversed-phase high-performance liquid chromatography: a ligand exchange mechanism.

In this paper we report a study on the mechanism of the enantiomeric separation of unmodified D,L-amino acids in RP-HPLC by copper(II) complexes of two tetradentate diaminodiamido ligands, (S,S)-N,N'-bis(phenylalanyl)ethanediamine (PheNN-2) and (S,S)-N,N'-bis(methylphenylalanyl)ethanediamine (Me2PheNN-2), added to the eluent. The aim is to investigate whether and how a copper(II) complex with no free equatorial positions can perform chiral discrimination of bidentate analytes such as unmodified amino acids. The problem is approached in a systematic way by: (a) varying the different chromatographic parameters (pH, selector concentration, eluent polarity); (b) performing chiral separation with the selector adsorbed on the stationary phase; (c) studying the ternary complex formation of these ligands with D- and L-amino acids in solution by glass electrode potentiometry and electrospray ionization MS. All the experimental data are consistent with a mechanism of chiral recognition, based on ligand exchange, which involves as selectors the species [Cu2L2H(-2)]2+ and [CuLH(-2)] and proceeds by displacement of two binding sites from the equatorial positions, giving rise to the ternary species [CuLA]+ and [CuLH(-1) A]. The most important factor responsible for chiral discrimination seems to be the affinity of the diastereomeric ternary complexes for the stationary phase since no enantioselectivity is observed in solution.

Amino Acids↗

PubMedDate not supplied

[Indicators of pulmonary epithelial damage among workers at a foundry exposed to airborne pollutants].

Foundry ambient air contains very high concentrations of noxious substances, such as particulate matter and gaseous pollutants, which can target the respiratory epithelium. Serum concentrations of the 16-kDa Clara cell protein (CC16-S) may reflect both the integrity of the epithelial barrier and smoke-induced Clara cell toxicity. To evaluate whether CC16-S is a sensitive biomarker of early respiratory disturbances, it was determined in a group of 35 foundry male workers (aged 41.1 +/- 6.9 years) examined both prior to and at the end of their work-shift (06:00 a.m.-02:00 p.m.). Exposure to inhalable/respirable dusts and PAH was characterized; urinary excretion of 1-hydroxypyrene (1-OH-P) and naphtol was measured to assess exposure to pyrene and naphthalene, respectively. CC16 serum levels decreased at the end of the shift (10.7 +/- 3.82 micrograms/L vs. 8.39 +/- 3.05 micrograms/L; p < 0.01); such decrements were significantly larger in more exposed workers. Although smokers had lower baseline values as compared to non smokers, both subgroups showed an average decrease of 30% in CC16-S concentrations at the end of shift. CC16-S was also negatively correlated with 1-OH-P, but not with naphtol concentrations. Decreased CC16-S levels can result from citotoxicity and would represent an useful biomarker of pneumotoxicity in foundry workers exposed to complex mixtures.

Air Pollution, Indoor↗

PubMedDate not supplied

[Data quality and the interpretation of biological monitoring results].

Quality assurance criteria are not uniformly applied to routine biological determination, in particular with regard to the biomonitoring of exposure to organic solvents. Quality assurance is not an abstract concept but rather a flexible tool which can be adapted to different situations, such as the measurement of different exposure levels or the use of different analytical methods, for a range of purposes (routine determination, risk assessment procedures, research). The occupational health physician should be actively involved in the definition of quality objectives, as well as in checking that they have been implemented. This paper deals with some general issues regarding quality assurance, and in particular with certain requirements of analytical quality (analytical uncertainty, imprecision, bias) and its implementation (quality control, reference materials, standardization, reference values), contextualized to the biological monitoring of organic compounds and the relative metabolites.

Environmental Monitoring↗

PubMedDate not supplied

[Heme oxygenase 1 expression in foundry workers].

Heme oxygenase 1 (HO-1) catalyses the oxidation of heme to biliverdin, and its expression is induced by oxidative stress. This study was aimed at assessing the role of metabolic polymorphisms (CYP1A1, CYP1B1, GSTM1, GSTP1, EPHX) in the modulation of HO-1 gene expression in 37 foundry workers. Blood and urine samples were obtained at the beginning (BS) and at the end (ES) of work shift, in February (T1) and June (T2). Urinary 1-hydroxypyrene (1-OHP) was measured as a tracer of PAH exposure. HO-1 gene expression in ES samples normalized to BS values (HO-1 ES/BS) was higher at T2 respect to T1. HO-1 gene induction was related to ES 1-OHP when considering either T2 samples or the combination of the two samplings. HO-1 ES/BS was significantly increased in subjects with at least a mutant allele for GSTP1 as compared to subjects with GSTP1AA genotype (1.23 +/- 0.002 vs 0.88 +/- 0.002, p < 0.05). Only in subjects with at least one vari.nt allele for GSTP1, a positive correlation between HO-1 ET/IT expression and 1-OHP FT levels was observed (r2 = 0.21, p = 0.016). The present study demonstrates a correlation between PAH exposure, as assessed by urinary 1-OHP, and the induction of HO-1 expression. Such a correlation seems to be limited to subjects bearing variant alleles for GSTP1. At the same exposure levels, these subjects showed a greater expression of HO-1 FT as compared to subjects with GSTP1 wild type genotype, possibly due to a higher oxidative stress in the subjects expressing the mutant GSTP1-1 isoform, which could imply a limited scavenging capacity.

Adult↗