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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The biological basis of autism spectrum disorders: evaluation of oxidative stress and erytrocyte membrane alterations

Ghezzo, Alessandro <1962> 14 April 2015 (has links)
This case-control study involved a total of 29 autistic children (Au) aged 6 to 12 years, and 28 gender and age-matched typically developing children (TD). We evaluated a high number of peripheral oxidative stress parameters, erythrocyte and lymphocyte membrane functional features and membrane lipid composition of erythrocyte. Erythrocyte TBARS, Peroxiredoxin II, Protein Carbonyl Groups and urinary HEL and isoprostane levels were elevated in AU (confirming an imbalance of the redox status of Au); other oxidative stress markers or associated parameters (urinary 8-oxo-dG, plasma Total antioxidant capacity and plasma carbonyl groups, erythrocyte SOD and catalase activities) were unchanged, whilst peroxiredoxin I showed a trend of elevated levels in red blood cells of Au children. A very significant reduction of both erythrocyte and lymphocyte Na+, K+-ATPase activity (NKA), a reduction of erythrocyte membrane fluidity, a reduction of phospatydyl serine exposition on erythrocyte membranes, an alteration in erythrocyte fatty acid membrane profile (increase in MUFA and in ω6/ω3 ratio due to decrease in EPA and DHA) and a reduction of cholesterol content of erythrocyte membrane were found in Au compared to TD, without change in erythrocyte membrane sialic acid content and in lymphocyte membrane fluidity. Some Au clinical features appear to be correlated with these findings; in particular, hyperactivity score appears to be related with some parameters of the lipidomic profile and membrane fluidity, and ADOS and CARS score are inversely related to peroxiredoxin II levels. Oxidative stress and erythrocyte structural and functional alterations may play a role in the pathogenesis of Autism Spectrum Disorders and could be potentially utilized as peripheral biomarkers.
2

Identificazione dei meccanismi molecolari responsabili del ruolo oncosoppressivo della molecola CD99 nell'osteosarcoma / Identification of molecular mechanisms responsible for the tumour suppressive role of CD99 in osteosarcoma

Pinca, Rosa Simona <1984> 14 April 2015 (has links)
CD99, glicoproteina di membrana codificata dal gene MIC2, è coinvolta in numerosi processi cellulari, inclusi adesione, migrazione, apoptosi, differenziamento e regolazione del trafficking intracellulare di proteine, in condizioni fisiologiche e patologiche. Nell’osteosarcoma risulta scarsamente espressa ed ha ruolo oncosoppressivo. L’isoforma completa (CD99wt) e l’isoforma tronca (CD99sh), deleta di una porzione del dominio intracellulare, influenzano in modo opposto la malignità tumorale. In questo studio, comparando cellule di osteosarcoma caratterizzate da differenti capacità metastatiche e diversa espressione di CD99, abbiamo valutato la modulazione dei contatti cellula-cellula, la riorganizzazione del citoscheletro di actina e la modulazione delle vie di segnalazione a valle del CD99, al fine di identificare i meccanismi molecolari regolati da questa molecola e responsabili del comportamento migratorio e invasivo delle cellule di osteosarcoma. L'espressione forzata di CD99wt induce il reclutamento di N-caderina e β-catenina a livello delle giunzioni aderenti ed inibisce l'espressione di molecole cruciali nel processo di rimodellamento del citoscheletro di actina, come ACTR2, ARPC1A, Rho-associated, coiled–coil-containing protein kinase 2 (ROCK2), nonché di ezrina, membro della famiglia ezrin/radixin/moesin e chiaramente associata con la progressione tumorale e la metastatizzazione dell’OS. Gli studi funzionali identificano ROCK2 come mediatore fondamentale nella regolazione della migrazione e della diffusione metastatica dell’osteosarcoma. Mantenendo cSRC in una conformazione inattiva, CD99wt inibisce la segnalazione mediata da ROCK2 inducendo una diminuzione dell’ezrina a livello della membrana accompagnata dalla traslocazione in membrana di N-caderina e β-catenina, principali ponti molecolari per il citoscheletro di actina. La ri-espressione di CD99wt, generalmente presente negli osteoblasti, ma perso nelle cellule di osteosarcoma, attraverso l'inibizione dell'attività di cSrc e ROCK2, aumenta la forza di contatto e riattiva i segnali anti-migratori ostacolando l’azione pro-migratoria, altrimenti dominante, dell’ezrina nell’osteosarcoma. Abbiamo infine valutato la funzione di ROCK2 nel sarcoma di Ewing: nonostante il ruolo oncogenico esercitato da CD99, ROCK2 guida la migrazione cellulare anche in questa neoplasia. / CD99, a transmembrane protein encoded by MIC2 gene is involved in multiple cellular events including cell adhesion, migration, apoptosis, cell differentiation and regulation of protein trafficking either in physiological or pathological conditions. In osteosarcoma, CD99 is expressed at low levels and functions as a tumour suppressor. The full-length protein (CD99wt) and the short-form harbouring a deletion in the intracytoplasmic domain (CD99sh) have been associated with distinct functional outcomes with respect to tumour malignancy. In this study, we evaluated modulation of cell-cell contacts, reorganisation of the actin cytoskeleton and modulation of signalling pathways by comparing osteosarcoma cells characterised by different metastasis capabilities and CD99 expression, to identify molecular mechanisms responsible for metastasis. Our data indicate that forced expression of CD99wt induces recruitment of N-cadherin and β-catenin to adherens junctions and inhibits the expression of several molecules crucial to the remodelling of the actin cytoskeleton, such as ACTR2, ARPC1A, Rho-associated coiled–coil containing protein kinase 2 (ROCK2) as well as ezrin, an ezrin/radixin/moesin family member that has been clearly associated with tumour progression and metastatic spread in osteosarcoma. Functional studies point to ROCK2 as a crucial intracellular mediator regulating osteosarcoma migration and metastatic spread. By maintaining cSrc in an inactive conformation, CD99wt inhibits ROCK2 signalling and this leads to ezrin decrease at cell membrane while N-cadherin and β-catenin translocate to the plasma membrane and function as main molecular bridges for actin cytoskeleton. We propose that the re-expression of CD99wt, which is generally present in osteoblasts but lost in osteosarcoma, through inhibition of cSrc and ROCK2 activity, manages to increase contact strength and reactivate stop-migration signals that counteract the otherwise dominant promigratory action of ezrin in osteosarcoma cells. We also assessed ROCK2 function in Ewing sarcoma cells: despite the oncogenic role exerted by CD99 in these tumour cells, ROCK2 still drives cell migration.
3

Genomic and Post-Genomic Analysis of Human Chromosome 21 in Relation to the Pathogenesis of Trisomy 21 (Down Syndrome)

Caracausi, Maria <1985> January 1900 (has links)
We performed an innovative systematic meta-analysis of gene expression profiles of whole normal human brain and heart to provide a quantitative transcriptome reference map of it, i.e. a typical reference value of expression for all the known, mapped and uncharacterized (unmapped) transcripts. For this reason, we used the software named TRAM (Transcriptome Mapper), which is able to generate transcriptome maps based on gene expression data from multiple sources. We also analyzed differential gene expression by comparing brain with human foetal brain, with a pool of non-brain tissues and with the three brain sub-region: cerebellum, cerebral cortex and hippocampus, the main regions severely affected with cognitive impairment, as seen in the case of trisomy 21. Data were downloaded from microarray databases, processed and analyzed using TRAM software and validated in vitro by assaying gene expression through several magnitude orders by "Real Time" reverse transcription polymerase chain reaction (RT-PCR). The excellent agreement between in silico and experimental data suggested that our transcriptome maps may be a useful quantitative reference benchmark for gene expression studies related to the human brain and heart. We also generated an integrated quantitative transcriptome map by systematic meta-analysis from all available gene expression profile datasets related to AMKL in paediatric age. The incidence of Acute Megakaryoblastic Leukemia (AMKL) is 500-fold higher in children with Down Syndrome (DS) compared with non-DS children. We present an integrated original model of the DS AMLK transcriptome, providing the identification of genes relevant for its pathophysiology which can potentially be new clinical markers. Finally, computational and molecular analysis of a highly restricted region of chromosome 21, which represents a strong candidate for typical DS features and is considered as intergenic, was performed. Northern Blot analysis and computational biology results show that HR-DSCR contain active loci bidirectionally transcribed.
4

Differenziamento macrofagico: gli effetti dei polimeri sintetici

Scordari, Alessandra <1980> 23 May 2008 (has links)
Research for new biocompatible and easily implantable materials continuously proposes new molecules and new substances with biological, chemical and physical characteristics, that are more and more adapted to aesthetic and reconstructive surgery and to the development of biomedical devices such as cardiovascular prostheses. Two classes of polymeric biomaterials seem to meet better these requirements: “hydrogels” , which includes polyalkylimide (PAI) and polyvinylalcohol (PVA) and “elastomers”, which includes polyurethanes (PUs). The first ones in the last decade have had a great application for soft tissue augmentation, due to their similarity to this tissue for their high water content, elasticity and oxygen permeability (Dini et al., 2005). The second ones, on the contrary, are widely used in cardiovascular applications (catheters, vascular grafts, ventricular assist devices, total artificial hearts) due to their good mechanical properties and hemocompatibility (Zdrahala R.J. and Zdrahala I.J., 1999). In the biocompatibility evaluation of these synthetic polymers, that is important for its potential use in clinical applications, a fundamental aspect is the knowledge of the polymers cytotoxicity and the effect of their interaction with cells, in particular with the cell populations involved in the inflammatory responses, i.e. monocyte/macrophages. In consideration of what above said, the aim of this study is the comprehension of the in vitro effect of PAI, PVA and PU on three cell lines that represent three different stages of macrophagic differentiation: U937 pro-monocytes, THP-1 monocytes and RAW 264.7 macrophages. Cytotoxicity was evaluated by measuring the rate of viability with MTT, Neutral Red and morphological analysis at light microscope in time-course dependent experiments. The influence of these polymers on monocyte/macrophage activation in terms of cells adhesion, monocyte differentiation in macrophages, antigens distribution, aspecific phagocytosis, fluid-phase endocitosis, pro-inflammatory cytokine (TNF-α, IL-1β, IL-6) and nitric oxide (NO) release was evaluated. In conclusion, our studies have indicated that the three different polymeric biomaterials are highly biocompatible, since they scarcely affected viability of U937, THP-1 and RAW 264.7 cells. Moreover, we have found that even though hydrogels and polyurethane influences monocyte/macrophage differentiation (depending on the particular type of cell and polymer), they are immunocompatible since they not induced significantly high cytokine release. For these reasons their clinical applications are strongly encouraged.
5

Variazione dell'espressione genica indotta dall'esercizio fisico moderato:effetti benefici per l'apparato cardiovascolare

Di Tullio, Simona <1973> 07 July 2009 (has links)
No description available.
6

Stress ossidativo ed adattamenti morfo-funzionali e biomolecolari in due condizioni opposte: denervazione ed esercizio fisico

Abruzzo, Provvidenza Maria <1981> 14 June 2010 (has links)
No description available.
7

Identificazione e dosaggio di marcatori molecolari dell'endometriosi nel sangue periferico / Identification and measurement of molecular markers of the endometriosis in peripheral blood

Elmakky, Amira <1982> 14 April 2011 (has links)
Purpose: to quantify the mRNA levels of MMP-3, MMP-9, VEGF and Survivin in peripheral blood and the serum levels of CA-125, Ca19-9 in women with and without endometriosis and to investigate the performance of these markers to differentiate between deep and ovarian endometriosis. Methods: a case controls study enrolled a series of 60 patients. Twenty controls have been matched with 20 cases of ovarian and 20 cases of deep endometriosis. Univariable and multivariable performance of serum CA125 and CA19-9, mRNA for Survivin, MMP9, MMP3 and VEGF genes have been evaluated by means of ROC curves and logistic regression respectively. Results: No difference in markers concentration were detected between ovarian and deep endometriosis. In comparison with controls serum CA19 and CA125 yielded the better sensitivity followed by mRNA for Survivin gene (81.5%, 51.9% and 7.5% at 10% false positive rate respectively). Multivariable estimated odds of endometriosis yielded a sensitivity of 87% at the same false positive rate. Conclusions: A combination of serum and molecular markers could allow a better diagnosis of endometriosis.
8

Caratterizzazione strutturale e funzionale di nuovi geni del cromosoma 21 umano con approccio integrato: dallo studio del locus CYYR1 alla meta-analisi di dati di espressione

Pelleri, Maria Chiara <1983> 14 April 2011 (has links)
No description available.
9

HIF1α regulates Mitochondrial biogenesis and Cellular senescence induced by Gamma Radiation

Bartoletti Stella, Anna <1984> 17 April 2013 (has links)
Cellular response to γ-rays is mediated by ATM-p53 axis. When p53 is phosphorylated, it can transactivate several genes to induce permanent cell cycle arrest (senescence) or apoptosis. Epithelial and mesenchymal cells are more resistant to radiation-induced apoptosis and respond mainly by activating senescence. Hence, tumor cells in a senescent state might remain as “dormant” malignant in fact through disruption of p53 function, cells may overcome growth arrest. Oncocytic features were acquired in the recurring neoplasia after radiation therapy in patient with colonrectal cancer. Oncocytic tumors are characterized by aberrant biogenesis and are mainly non-aggressive neoplasms. Their low proliferation degree can be explained by chronic destabilization of HIF1α, which presides to adaptation to hypoxia and also plays a pivotal role in hypoxia-related radio-resistance. The aim of the present thesis was to verify whether mitochondrial biogenesis can be induced following radiation treatment, in relation of HIF1α status and whether is predictive of a senescence response. In this study was demonstrate that mitochondrial biogenesis parameters like mitochondrial DNA copy number could be used for the prediction of hypoxic status of tissue after radiation treatment. γ-rays induce an increase of mitochondrial mass and function, in response to a genotoxic stress that pushes cells into senescence. Mitochondrial biogenesis is only indirectly regulated by p53, whose activation triggers a MDM2-mediated HIF1α degradation, leading to the release of PGC-1β inhibition by HIF1α. On the other hand, this protein blunts the mitochondrial response to γ-rays as well as the induction of p21-mediated cell senescence, indicating prevalence of the hypoxic over the genotoxic response. Finally in vivo, post-radiotherapy mtDNA copy number increase well correlates with lack of HIF1α increase in the tissue, concluding this may be a useful molecular tool to infer the trigger of a hypoxic response during radiotherapy, which may lead to failure of activation of senescence.
10

The role of mitochondria in the regulation of gamma rays induced mTOR-dependent senescence

Mariani, Elisa <1982> 05 June 2012 (has links)
The first aims of this study were to demonstrate if mitochondrial biogenesis and senescence can be induced simultaneously in cell lines upon exposure to a genotoxic stress, and if the presence of mtDNA mutations which impair the functionality of respiratory complexes can influence the ability of a cell to activate senescence. The data obtained on the oncocytic model XTC.UC1 demonstrated that the presence of mitochondrial dysfunction is involved in the maintenance of a senescent phenotype induced by γ-rays treatment. The involvement of mTORC1 in the regulation of senescence has been shown in this cell line. On the other hand, in cells which do not present mitochondrial dysfunction it has been verified that genotoxic stress determines the activation of both mitochondrial biogenesis and senescence. Further studies are necessary in order to verify if mitochondrial biogenesis sustains the activation of senescence. The second aim of this thesis was to determine the involvement of mTORC1 in the regulation of PGC-1α expression, in order to verify what is the cause of the development of oncocytoma in patients affected by two hereditary cancer syndromes; Cowden and Birt-hogg-Dubé . The study of oncocytic tumors developed by patients affected by these syndromes suggested that the double heterozigosity of the two causative genes, PTEN and FLCN respectively, induce the activation of mTORC1 and therefore the activation of PGC-1α expression. On XTC.UC1 cell line, the most suitable in vitro model, experiments of complementation of PTEN and FLCN were conducted. To date, these results demonstrated that mTORC1 is not involved in the regulation of PGC-1α expression, and PTEN and FLCN seem to have opposite effect on PGC-1α expression.

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