1,721,204 research outputs found
A mathematical approach to study combined effects of toxicants in vitro: Evaluation of the Bliss independence criterion and the Loewe additivity model
No full textThe study of interactions among toxicants is of fundamental interest and practical importance in toxicological sciences. However, a final agreement on the definition of agent interaction is lacking, and therefore, particular care should be adopted when using the terms additivity, synergism and antagonism, unless the exact toxicological pathways of the compounds studied are known. Two main different approaches, the Bliss independence criterion and the Loewe additivity model, have been generally used in co-exposure experiments. In some cases, they can present dramatically different results, depending on the slope of the pure dose-response curves of single substances. Here, we consider both models in in vitro experiments, where the dose-response curves can be extrapolated. Advantages and limitations of both approaches are discussed, using several mathematical simulations to better explain them, and applying the Hill function for the dose-response model curve. Overall we conclude that the Loewe additivity model is slightly preferable because of a general higher biological plausibility. However, which model to use must be determined case by case and the evaluation can be aided by experimental approaches, such as the study of multiple biomarkers and asynchronous exposures. © 2007 Elsevier Ltd. All rights reserved
[New perspectives in biomonitoring of metallic elements: the example of hexavalent chromium]
No full textPlating industry is an important productive sector in all the national territory, because of its contribution to a high number of industrial products and crafts. In the chrome plating sector there is a specific chemical risk due to the exposure to compounds containing hexavalent Chromium [Cr(VI)]. Exhaled breath condensate (EBC) has been used to study both acute and long term exposure to Cr(VI) in chrome plating workers. Cr-EBC correlates with specific oxidative stress biomarkers. Moreover, both total Cr and its hexavalent fraction can be measured in EBC, which therefore is a promising biological fluid to assess the absorbed dose at the target organ level, the pulmonary reduction kinetics of Cr(VI) and in general its local pneumotoxic effects. EBC collection and analysis could give additional information to the traditional measures performed during biomonitoring
Unfolding and partial refolding of Apo and Olo 5S monomer of Carcinus Aestuarii hemocyanin
No full textA review on airway biomarkers: exposure, effect and susceptibility
No full textCurrent research in pulmonology requires the use of biomarkers to investigate airway exposure and diseases, for both diagnostic and prognostic purposes. The traditional approach based on invasive approaches (lung lavages and biopsies) can now be replaced, at least in part, through the use of non invasively collected specimens (sputum and breath), in which biomarkers of exposure, effect and susceptibility can be searched. The discovery of specific lung-related proteins, which can spill over in blood or excreted in urine, further enhanced the spectrum of airway specific biomarkers to be studied. The recent introduction of high-performance 'omic' technologies - genomics, proteomics and metabolomics, and the rate at which biomarker candidates are being discovered, will permit the use of a combination of biomarkers for a more precise selection of patient with different outcomes and responses to therapies. The aim of this review is to critically evaluate the use of airway biomarkers in the context of research and clinical practice
Exhaled nitric oxide in occupational respiratory medicine and environmental health: State of art
No full textNitric oxide is a gas detectable in exhaled breath of humans and is recognized as a useful biomarker for asthma diagnosis and mon- itoring. Several studies have shown evidence of higher levels of exhaled nitric oxide in patients with respiratory diseases as com- pared with the healthy population. The possibility of using exhaled nitric oxide measurement as a tool for diagnosing and monitoring occupational exposures to allergic or toxic irritants is reviewed and discussed
Metallic elements in exhaled breath condensate as a measure of long term inhalatory exposure in COPD.
No full textA long-term prospective follow-up study of incident RLS in the course of chronic DAergic therapy in newly diagnosed untreated patients with Parkinson's disease
No full textIt is currently controversial if and in which terms Parkinson's disease (PD) and restless legs syndrome (RLS) are linked in co-morbid association. In a cohort of 106 de novo PD patients (67 male and 39 female, aged 42-83 years), 15 of them developed RLS, which was prospectively assessed at 6-month intervals from the starting of dopamine(DA)ergic therapy. The incidence rate of total RLS was 47 per 1,000 case/person per year and 37 per 1,000 case/person per year after the exclusion of possible "secondary" forms of the disorder (n = 3). These figures are higher than those reported in an incidence study conducted in German general population (Study of Health in Pomerania), in which the method of ascertainment of RLS similar to ours has been used. An incidence rate of total RLS significantly higher than that reported in the above-mentioned study was found in the age ranges 55-64 years and in the age range 45-74 years standardized to European general population 2013 (70 and 53 per 1,000 case/person per year, respectively, p < 0.01). Ten out of 12 patients (83.3 %) developed RLS within 24 months from the starting of DAergic medication (median latency 7.5 months). These findings support the view that sustained DAergic therapy could represent the critical factor inducing an increased incidence of RLS in patients with PD and that the latter disease should be regarded as the condition predisposing to the occurrence of the former and not viceversa as previously hypothesized. The mechanism underlying the increased incidence of RLS remains unclear and deserves further investigation
- …
