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Predisposizione e valutazione critica di scenari di esposizione in ambito REACh: sostanze ad attività disendocrina (Ftalati).
No full textThe new REACH legislation formally introduces the control and development of exposure scenarios for substances deemed capable of altering the hormonal system. Example of compounds that alter the endocrine system (endocrine disruptors) and subject of this thesis are the phthalates.
Phthalates are organic chemicals derived by esterification of phthalic anhydride. They are used to make soft and flexible a variety of products, including toys. These articles are used by children, most likely subpopulation.
The main objective of the project is to conduct a risk assessment for these substances. The first phase of the evaluation was to determine the toxic properties of these substances (by literature search), after that, taking into account the most likely population, we have been developed hypothetical scenarios of exposure (using the software ConsExpo) for 3 classes: Babies (4.5 months), newborn (7.5 months), children (13.5 months).
Finally, to perform the risk characterization, was made in connection the dangers of these substances with the exposure and was rated the likelihood or occurrence of adverse effects on children.
The results obtained from the risk assessment (using as a method the Margin of Safety), lead to the conclusion that there is a negligible risk in the use of toys containing phthalates even if concentration was above legal limits (DEHP: 43.3%, and DINP: 49.9%).
Although the results are encouraging, in the future will need to conduct further analysis and risk assessment for phthalates, taking into account the cumulative effect of the different phthalates and the effect of phthalates and other substances with the same mechanism of action or the same target organs
Sviluppo di metodiche analitiche per lo studio e la caratterizzazione di beni culturali.
No full textIn recent years, the investigation of artworks has increasingly been characterized by a cross cutting approach. Archaeologists, art historians, conservators and applied scientists collaborate on issues such as the evaluation of the artistic techniques, provenance and dating studies, diagnostic campaigns. The present thesis, inspired by this philosophy, was focused on two research branches: the investigation of ancient mortars and the elemental analysis of archaeological bones by means of different analytical techniques, defining and optimizing the experimental parameters.
Historical mortars are among the most widespread building materials since ancient times. The uncovering of their composition is a challenge for chemists, being constitued by a binder and an aggregate phase, sometimes with additives. Three case studies were considered: the Mediaeval Arsenal of Amalfi (SA), the Roman CAstrum of Laino in Val d'Intelvi (CO) and the archaeological site of Baradello Castle in Como. A key point emerged: the analytical method has not yet been standardized, preventing reliable and robust results. Thus, a protocol of chemical-mineralogical analysis was set up in collaboration with geologists.
Coming to bones, the study of archaeological human remains is an important tool to discover information about past civilities. Some trace elements such as zinc and strontium are markers of the so-called paleodiet and can be used to reconstruct whether it was characterized by vegetables or meat. A whole analytical protocol was set up for the determination of trace elements in bones by Inductively Coupled Plasma Mass Spectrometry and then applied to samples coming from the prehistorical Necropolis of San Giorgio Valdaro (MN)
Ecology and conservation of red-backed shrike (Lanius collurio) in semi-natural habitats of north-western Italy.
No full textSpecies conservation largely depends on knowledge of habitat needs of target species. On the other hand, breeding habitat plays an essential role in the life-history of birds. Many bird species are currently threatened by unfavourable environmental changes or by habitat destruction or degradation prompted by human activities, in particular farmland birds. This dramatic and widespread decline has been related to agricultural intensification, especially through loss of ecological heterogeneity. Also land abandonment, which mainly affects marginal areas and is often indirectly caused by intensification, negatively affects several bird species.
The red-backed shrike Lanius collurio (Aves: Laniidae) is a typical passerine species of Euroasiatic low-intensity farmland landscapes and is one of the species most sensitive to agricultural changes.
This species underwent large declines over most of Europe during the last century, disappearing almost completely from large areas, and being consequently listed in the Annex I of the Birds Directive (79/409/EEC). The main reason for the decline is probably linked to the increased intensification and mechanization of traditional agriculture, which led to unfavourable changes of breeding habitats. However, conditions in the African wintering grounds or migratory stop-over areas may also have affected its population status. Recently, some studies have tried to address habitat determinants of species’ occurrence and breeding performance in many areas, but studies in southern Europe are still scarce and most works deal with central or northern Europe.
Lombardy, northern Italy, includes portions of both the Alpine and Apennine chains, which at intermediate elevations host key populations of red-backed shrike. Lowland areas in the region have undergone heavy agricultural intensification (generally heavier than in the rest of Italy), resulting in wide extensions of specialized cultivations, often with a single crop occupying tens or hundreds of hectares (especially Zea mais), without marginal features (as hedges, shrubs or tree patches).
Therefore, conservation of farmland birds in hilly and mountain areas, where changes of agricultural practices have been less dramatic, is a priority for bird conservation in Italy, and especially in Lombardy. At the same time, land abandonment is dramatically reducing open habitats in hilly and mountain portions of the region, thus leading to further unsuitable modification to the breeding habitats of shrikes and other farmland or ecotonal species.
Red-backed shrike is one of the most threatened species in Lombardy and is listed among conservation priority species by the regional government. Although the species seems to have dramatically declined, for example in Varese and Bergamo provinces, few quantitative data are available to compare the current and previous estimates of population size and distribution.
We developed a multi-level conservation strategy for Lanius collurio in Lombardy, starting from a regional-wide assessment of habitat preferences, whose results were translated into conservation priorities over different spatial scales and in a regional Action Plan for the conservation of the species.
After defining habitat associations, we i) described conservation priorities (at landscape scale) over the whole region, by identifying the most important populations of the species, main areas of potential occurrence and main threats and conservation needs in terms of large-scale habitat change, ii) derived territory-level guidelines for management of different habitats occupied by the species.
Management guidelines include a description of the habitat mosaic virtually representing the most suitable option for the species in different environmental contexts (permanent grasslands, pastures, shrublands, heathlands, vineyards) inhabited by L. collurio in Lombardy and best practices favourable for the species. On average, the definition of proportion of habitat variables in an ideal territory of a breeding pair of red – backed shrike in Lombardy includes: 60% of grazed or mowed grasslands; 20% of bushes; 10% of untilled grasslands; 70 meters of hedges; 60 meters of fences.
Furthermore, for each suitable breeding habitat for the species in Lombardy we determined the ideal mosaic of vegetation in one hectare of surface that can hosts a breeding pair of red-backed shrike (e.g. for permanent grasslands: 73% mowed of grazed grassland; 12% untilled grassland; 10% shrubs; 5% hedges).
Finally, an ‘Action Plan for the conservation of Red-Backed Shrike in Lombardy’ was produced, based on a long-term strategy of conservation of the species in Lombardy region. Its adoption by the regional government of Lombardy is currently under way
The proteomic approach to investigate Parkinson's desease: pathogenetic mechanisms and biomarkers discovery.
No full textThe overall goals of basic research in improving the clinical approach to a disease are, on the one hand, to unravel its natural history, finding its cause and developing better treatments and, on the other hand, to find biomarkers that would permit to ameliorate the diagnosis, to distinguish among patient subtypes and to set up clinical trials of new therapeutic agents. The common threads of the two projects developed in this thesis are the technique used, proteomics, and the main object, Parkinson‟s disease (PD). Proteomics is a powerful methodology to investigate how protein expression is affected in the pathogenesis of a disease process and should be exploited both to investigate PD pathogenetic mechanisms and to discover peripheral biomarkers.
In the first part of this thesis the project “A SH-SY5Y model to investigate PD pathogenetic mechanisms” is discussed. We investigated the expression pattern of cellular proteins following dopamine exposure in catecholaminergic SH-SY5Y human neuroblastoma cells overexpressing α-synuclein by a proteomic approach. Using 2D gel image analysis and ANOVA statistics we identified proteins that correlate with the experimental conditions in our model. Significant changes in specific cellular processes were observed, such as cytoskeleton structure and regulation, mitochondrial function, energetic metabolism, protein synthesis and neuronal plasticity. Proteins were analyzed by a network enrichment tool that automatically enriched the network model in terms of the most relevant proteins that seem to be missing. Moreover, the bioinformatic approach found out the enriched Gene Ontology (GO) categories, allowing us to draw attention to the NF-κB pathway. To validate experimentally the hypothesis of the NF-κB involvement, we performed a luciferase gene reporter assay that revealed a downregulation of the transcription factor activation by α-synuclein increased expression and its complete quenching by dopamine exposure.
Each element arising from the present study could represent a valuable starting point for focused investigations aimed to better understand key issue of PD pathogenesis. For instance, a protein that completely disappeared after dopamine treatment was VDAC2, a porin of the outer mitochondrial membrane. Since the impairment of mitochondrial function is considered among the major pathogenetic factors of neurodegeneration in PD, we further investigated the regulation of VDAC2 degradation and the role of its phosphorylation.
Accumulating evidence supports a specific role of DJ-1 in protecting dopaminergic neurons from dopamine itself. Since this protein act as a pool of different forms possibly associated to different function and localization, we analyzed DJ-1 2D electrophoresis pattern in SH-SY5Y cells after exposure to dopamine; we observed a specific increase in the most acidic forms in the pattern together with a significant decrease of the most basic spot. Unlike cells exposed to generic oxidative conditions, no additional shift was observed. The results are corroborated by a meta-analysis of the literature showing that in the absence of dopamine treatment the specific acidic form is underrepresented.
The second part of the thesis is focused on the project “Dopamine response of dopaminergic circulating cells: the Jurkat cell model”. The functions of immune cells are regulated not only by cytokines, but also by several neurotransmitters. In particular, peripheral blood lymphocytes possess a complex dopaminergic regulatory system. Human T-lymphocytes express all five dopamine receptors (D1-D5), each of which exerts different actions on the regulation of T-cell functions. The Jurkat human leukemia CD4+ T-cell line has been thoroughly used and characterized as a suitable cell model to investigate T-cell signaling and apoptosis, nevertheless its characterization as a model of circulating dopaminergic cells was never reported before. In this regard, we characterized the dopaminergic system in Jurkat cells and through a proteomic approach we analyzed their response to a dopamine challenge in order to highlight metabolic pathways that could specifically reveal alterations linked to PD. A dopamine challenge, with no effect on cell viability (50 μM), induced quantitative changes in the protein expression pattern. The proteins that showed quantitative differences were identified by peptide mass fingerprinting and analyzed in terms of both interaction network and GO classification enrichment. We obtained a significant model for network enrichment and a functional association to GO classification (unfolded protein binding). Eventually, we observed a modification of β-actin and 14-3-3 two-dimensional pattern following dopamine exposure.
In both projects, by combining the experimental and the bioinformatic approach, we fulfilled the expectations for proteomics to generate new hypotheses. Of course, one must consider that models have limitations and that hypotheses need further validation, but they could be a good starting-point to unravel biochemical pathways altered in PD, a disease with a poorly understood etiology
Provisional odels for management and conservation of Alpine fauna: the red deer (Cervus elaphus) case in the Stelvio National Park.
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Gold catalyzed heterocyclization processes.
No full textThe work done in the present doctoral thesis, developed in the GlaxoSmithKline Medicine Research Center Laboratories and in collaboration with the Insubria University of Como, was focused on heterocyclization processes in organic chemistry catalyzed by gold. This metal confirmed its interesting carbophylic properities of activating double and triple carbon-carbon bonds toward various nucleophiles both in inter-and intramolecular way. Three main topics are mainly covered in this work. The first concerns gold catalyzed intramolecular hydroamination of α-aminoallenamides for the preparation of 2-vinylimidazolidinones by means of nucleophilic attack of the amino group on the inside double bond of the diene moiety. This is the first example of gold catalyzed cyclization on allene substrates bearing an amido group which however resulted inactive.
The second topic deals with the development of a simple procedure for the intramolecular hydroarylation of N-alkynyl pyrrole-2-carboxamide accomplished by gold(III)-catalysis. The outcome of the reaction led to differently substituted bicyclic pyrrolo-fused products arising either from direct cylization or from a formal rearrangement of the carboxamide group. The substrates containing a propargyl group afforded pyrrolo[2,3-c]pyridine and pyrrolo[3,2-c]pyridine derivatives in a ratio depending on the reaction solvent. When bearing a phenyl group at the C-C triple bond, the pyrrolylamides furnished pyrrolo[2,3-c]azepines and pyrrolo[3,2-c]azepines which ratio depends once again on the used solvent.
The last but not the least is aimed on the development of an efficient gold-catalyzed procedure to synthesize 2-alkylidene-3,4-dihydro-2H-1,4-benzoxazines starting from 2-alkynyl-substitued phenols. This is an intramolecular hydroalkoxylation reaction on alkynes tethered to a phenol moiety that represents a valuable alternative to already reported transition-metal-catalyzed procedures
Il Diritto Naturale dell'appropriazione: Ugo Grozio tra accumulazione originaria e potere sovrano.
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Np95 è coinvolta nel mantenimento dell’informazione epigenetica della cromatina associata a repressione trascrizionale in cellule replicanti e P19 indotte a differenziare a neuroni.
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