Expression of Mast Cell Proteases Correlates with Mast Cell Maturation and Angiogenesis during Tumor Progression

Tumor cells are surrounded by infiltrating inflammatory cells, such as lymphocytes, neutrophils, macrophages, and mast cells. A body of evidence indicates that mast cells are associated with various types of tumors. Although role of mast cells can be directly related to their granule content, their function in angiogenesis and tumor progression remains obscure. This study aims to understand the role of mast cells in these processes. Tumors were chemically induced in BALB/c mice and tumor progression was divided into Phases I, II and III. Phase I tumors exhibited a large number of mast cells, which increased in phase II and remained unchanged in phase III. The expression of mouse mast cell protease (mMCP)-4, mMCP-5, mMCP-6, mMCP-7, and carboxypeptidase A were analyzed at the 3 stages. Our results show that with the exception of mMCP-4 expression of these mast cell chymase (mMCP-5), tryptases (mMCP-6 and 7), and carboxypeptidase A (mMC-CPA) increased during tumor progression. Chymase and tryptase activity increased at all stages of tumor progression whereas the number of mast cells remained constant from phase II to III. The number of new blood vessels increased significantly in phase I, while in phases II and III an enlargement of existing blood vessels occurred. In vitro, mMCP-6 and 7 are able to induce vessel formation. The present study suggests that mast cells are involved in induction of angiogenesis in the early stages of tumor development and in modulating blood vessel growth in the later stages of tumor progression.

Purging e alte dosi di chemioterapia con reinfusione di cellule staminali autologhe in linfomi non Hodgkin follicolari resistenti/refrattari

In the era of monoclonal antibodies the role of autologous stem cell transplantation (ASCT) in the management of follicular lymphoma (FL) is still debated. To evaluate the safety and efficacy of myeloablative therapy with rescue of purged or unpurged harvests in FL pts. At our institution form 1997 to 2007 28 pts with refractory/resistant FL were eligible for ASCT. Before high dose therapy they received 2-3 cycles of CHOP-like regimen (ACOD), followed by Cyclophosphamide 4g/mq to mobilize the stem cells (SC). After SC collection the pts underwent 3 cycles of subcutaneous Cladribine at a daily dose of 0,14-0,10 mg/Kg for Day 1-5 every 3-4 weeks. The conditioning regimen was based on Mitoxantrone 60mg/mq + Melphalan 180 mg/mq, followed by SC re-infusion 24-hours later and G-CSF starting 24 hours after re-infusion. In 19 pts the SC underwent purging: in 10 harvests the CD34+ were selected by immunomagnetic beads, while in the other 9 pts, only Rituximab was used as “purging in vivo” agent. The remaining 9 pts received unpurged SC. Before ASCT 11 pts were in complete response (CR), 9 in partial response (PR) and 2 in stable disease. Two pts were not eligible for ASCT because of progressive disease (PD). The remaining 25 pts were eligible for ASCT. The engraftment was at a median of 11 days for leucocytes and 14 days for platelets (>20.000/mmc), with a delay of one day in the pts, who received purged SC. Grade 3-4 mucositis was described in 8 pts. During aplasia a 48% infection rate was reported, without differences between pts with purged or unpurged SC. One patient in CR presented myelodysplastic syndrome at 18 months from ASCT. After ASCT 22 pts were in CR, 2 in PR and one patient were not valuable, because died before response assessment. Nine pts in CR showed PD at a median time of 14 months from ASCT. With a median follow up of 5 years (range 2 months -10 years), 22 pts are alive and 11 (44%) in CR. Ten pts died, 5 for progressive disease and 5 for treatment-related causes; in particular 7 of them received in-vitro purged SC. Conclusions: Our chemotherapy regimen, which included the purine analogue Cladribine in the induction phase, seems safe and feasible. The high rate of CR reported and the sustained freedom from progression up to now, makes such modality of treatment a valid option principally in relapsing FL patients. In our experience, the addition of a monoclonal antibody as part of treatment confirms its role “in vivo purging” without observing an increased incidence of infection.

Il trapianto di midollo osseo aploidentico nelle patologie oncoematologiche: studio clinico

L’argomento della presente tesi di dottorato riguarda lo studio clinico del trapianto di cellule staminali emopoietiche aploidentiche nelle patologie oncoematologiche. Nel periodo di tempo compreso tra 1/12/2005 ed il 30/10/2007 sono stati arruolati 10 pazienti (6 LAM, 3 LAL, 1 LMC in crisi blastica mieloide) nell’ambito di uno studio clinico che prevedeva il trapianto di midollo osseo aploidentico per pazienti affetti da patologia oncoematologica in prima o successiva recidiva, per i quali non fosse disponibile un donatore di midollo osseo consanguineo o da banca. Lo schema di condizionamento al trapianto di midollo osseo utilizzato era il seguente: Fludarabina 150/m2, Busulfano orale 14mg/kg, Tiothepa 10mg/kg e Ciclofosfamide 160mg/kg. Per la profilassi della malattia da trapianto contro l’ospite è stata somministrata timoglobulina antilinfocitaria (ATG) al dosaggio complessivo di 12.5 mg/kg, short course metotrexate (+1, +3 e +11), cortisone e ciclosporina con tapering precoce al + 60. I pazienti hanno reinfuso una megadose di cellule CD34+ mediana pari a 12.8x106/kg. Tre pazienti non sono valutabili per l’attecchimento a causa di rigetto (1/3) o morte precoce (2/3). Sette pazienti sono valutabili per l’attecchimento; per questi pazienti il tempo mediano a 500 PMN/mmc e a 20 x 109/l piastrine è stato rispettivamente di 17 e 20 giorni. Quattro pazienti su 7 hanno svillupato una Graft versus Host Disease (GVHD) acuta di grado II-IV, mentre soltanto 1/7 ha sviluppato una GVHD cronica. Sette pazienti su 10 trapiantati hanno ottenuto una remissione completa successivamente al trapianto. Di questi, attualmente 2 pazienti sono vivi in remissione completa, mentre gli altri 5 sono ricaduti e successivamente deceduti. In conclusione, il trapianto aploidentico è una procedura fattibile ed efficace. Tale procedura è in grado di garantire un 20% di lungo sopravviventi in un setting di pazienti a prognosi estremamente infausta.

Outcome of HIV-infected patients with hepatocellular carcinoma: a comparison with HIV negative controls

Background and rationale for the study. This study investigated whether human immunodeficiency virus (HIV) infection adversely affects the prognosis of patients diagnosed with hepatocellular carcinoma (HCC).Thirty-four HIV-positive patients with chronic liver disease, consecutively diagnosed with HCC from 1998 to 2007 were one-to-one matched with 34 HIV negative controls for: sex, liver function (Child-Turcotte-Pugh class [CTP]), cancer stage (BCLC model) and, whenever possible, age, etiology of liver disease and modality of cancer diagnosis. Survival in the two groups and independent prognostic predictors were assessed. Results. Among HIV patients 88% were receiving HAART. HIV-RNA was undetectable in 65% of cases; median lymphocyte CD4+ count was 368.5/mmc. Etiology of liver disease was mostly related to HCV infection. CTP class was: A in 38%, B in 41%, C in 21% of cases. BCLC cancer stage was: early in 50%, intermediate in 23.5%, advanced in 5.9%, end-stage in 20.6% of cases. HCC treatments and death causes did not differ between the two groups. Median survival did not differ, being 16 months (95% CI: 6-26) in HIV positive and 23 months (95% CI: 5-41) in HIV negative patients (P=0.391). BCLC cancer stage and HCC treatment proved to be independent predictors of survival both in the whole population and in HIV patients. Conclusions. Survival of HIV infected patients receiving antiretroviral therapy and diagnosed with HCC is similar to that of HIV negative patients bearing this tumor. Prognosis is determined by the cancer bulk and its treatment.

Studio e sviluppo di tecniche per la produzione di nanocompositi a matrice di alluminio

Foundry aluminum alloys play a fundamental role in several industrial fields, as they are employed in the production of several components in a wide range of applications. Moreover, these alloys can be employed as matrix for the development of Metal Matrix Composites (MMC), whose reinforcing phases may have different composition, shape and dimension. Ceramic particle reinforced MMCs are particular interesting due to their isotropic properties and their high temperature resistance. For this kind of composites, usually, decreasing the size of the reinforcing phase leads to the increase of mechanical properties. For this reason, in the last 30 years, the research has developed micro-reinforced composites at first, characterized by low ductility, and more recently nano-reinforced ones (the so called metal matrix nanocomposite, MMNCs). The nanocomposites can be obtained through several production routes: they can be divided in in-situ techniques, where the reinforcing phase is generated during the composite production through appropriate chemical reactions, and ex situ techniques, where ceramic dispersoids are added to the matrix once already formed. The enhancement in mechanical properties of MMNCs is proved by several studies; nevertheless, it is necessary to address some issues related to each processing route, as the control of process parameters and the effort to obtain an effective dispersion of the nanoparticles in the matrix, which sometimes actually restrict the use of these materials at industrial level. In this work of thesis, a feasibility study and implementation of production processes for Aluminum and AlSi7Mg based-MMNCs was conducted. The attention was focused on the in-situ process of gas bubbling, with the aim to obtain an aluminum oxide reinforcing phase, generated by the chemical reaction between the molten matrix and industrial dry air injected in the melt. Moreover, for what concerns the ex-situ techniques, stir casting process was studied and applied to introduce alumina nanoparticles in the same matrix alloys. The obtained samples were characterized through optical and electronic microscopy, then by micro-hardness tests, in order to evaluate possible improvements in mechanical properties of the materials.

Portal hypertension: a comparison between portal-venous pressure measurement and ARFI measurement of liver and spleen stiffness

PURPOSE. Portal pressure is measured invasively as Hepatic Venous Pressure Gradient (HVPG) in the angiography room. Liver stiffness measured by Fibroscan was shown to correlate with HVPG values below 12 mmHg. This is not surprising, since in cirrhosis the increase of portal pressure is not directly linked with liver fibrosis and consequently to liver stiffness. We hypothesized that, given the spleen’s privileged location upstream to the whole portal system, splenic stiffness could provide relevant information about portal pressure. Aim of the study was to assess the relationship between liver and spleen stiffness measured by Virtual Touch™ (ARFI) and HVPG in cirrhotic patients. METHODS. 40 consecutive patients (30 males, mean age 62y, mean BMI=26, mean Child-Pugh A6, mean platelet count=92.000/mmc, 19 HCV+, 7 with ascites) underwent to ARFI stiffness measurement (10 valid measurements in right liver lobe both surface and centre, left lobe and 20 in the spleen) and HPVG, blindly to each other. Median ARFI values of 10 samplings on every liver area and of 20 samplings on spleen were calculated. RESULTS. Stiffness could be easily measured in all patients with ARFI, resulting a mean of 2,61±0,76, 2,5±0,62 and 2,55±0,66 m/sec in the liver areas and 3.3±0,5 m/s in the spleen. Median HPVG was 14 mmHg (range 5-27); 28 patients showed values ≥10 mmHg. A positive significant correlation was found between spleen stiffness and HPVG values (r=0.744, p<0.001). No significant correlation was found between all liver stiffness and HVPG (p>0,05). AUROC was calculated to test spleen stiffness ability in discriminating patients with HVPG ≥10. AUROC = 0.911 was obtained, with sensitivity of 69% and specificity of 91% at a cut-off of 3.26 m/s. CONCLUSION. Spleen stiffness measurement with ARFI correlates with HVPG in patients with cirrhosis, with a potential of identifying patients with clinically significant portal hypertension.

Caratterizzazione di profili estrusi in lega di magnesio ZM21 caricata con carburo di silicio

L’attività sperimentale presentata in questo elaborato è volta a conoscere le proprietà meccaniche di una lega di magnesio rinforzata con particelle ceramiche (Carburo di silicio SiC). Scopo del lavoro sarà pertanto il confronto fra le proprietà meccaniche del materiale base ZM21 rispetto al materiale prodotto in Israele con rinforzo di carburo di silicio, con particolare riferimento alle proprietà a trazione, a compressione e alla distribuzione di particelle nella matrice (analisi metallografica).

Sviluppo di metodologie per l'analisi di composti organici prodotti dalla fermentazione di frazioni pirolitiche della biomassa

I processi microbiologici rivestono una grande importanza nello sviluppo di combustibili e sostanze chimiche da fonti rinnovabili (biomassa), quali: il biometano e le bioplastiche, come i poli(idrossialcanoati), PHA. I PHA sono poliesteri ottenuti per condensazione di 3-idrossiacidi, il più comune dei quali è il poli(3-idrossibutirrato, PHB). Gli alti costi di produzione del PHA da colture microbiche singole ha portato a valutare nuove strategie, tra cui l’utilizzo di colture microbiche miste (MMC) e substrati di scarto. Il bio-olio ottenuto dalla pirolisi di biomassa potrebbe essere un substrato interessante per la produzione di biogas e PHA. Gli acidi a catena corta (acidi grassi volatili, VFA), infatti, sono i prodotti intermedi nella produzione sia di biogas che di PHA. L’analisi di questi ultimi viene normalmente effettuata tramite GC-FID o GC-MS. La degradazione termica (pirolisi, Py) di PHA produce acidi alchenoici caratteristici, come l’acido crotonico. Il metodo tradizionale per la determinazione del PHA è la metanolisi seguita da un’analisi GC-MS, una procedura laboriosa con uso di solventi clorurati e sostanze corrosive. Lo scopo principale di questa tesi è stato quello di sviluppare un nuovo metodo di analisi dei PHA. Il metodo studiato si basa sulla pirolisi diretta della biomassa e determinazione degli acidi alchenoici prodotti dalla degradazione del PHA in GC-FID. La pirolisi analitica è stata studiata tramite analisi di polimeri puri (per la calibrazione) e poi è stata applicata a campioni batterici derivanti da MMC e a ceppi selezionati. Il confronto con il metodo convenzionale ha dimostrato che la Py/GC-FID è un metodo valido per l’identificazione dei PHA e per la loro quantificazione nelle matrici batteriche. Il pre-trattamento del campione è minimo e non richiede l’uso di solventi e reagenti chimici. Inoltre, è stata applicata una tecnica di analisi dei VFA nei test di biometanazione basata sull’estrazione con una microquantità di dimetilcarbonato.

Studio, simulazione e verifica sperimentale di tecniche di controllo per convertitori multilivello modulari

L’evoluzione dei componenti elettronici di potenza ed il conseguente sviluppo dei convertitori statici dell’energia elettrica hanno consentito di ottenere un’elevata efficienza energetica, sia nell’ambito degli azionamenti elettrici, sia nell’ambito della trasmissione e distribuzione dell’energia elettrica. L’efficienza energetica è una questione molto importante nell’attuale contesto storico, in quanto si sta facendo fronte ad una elevatissima richiesta di energia, sfruttando prevalentemente fonti di energia non rinnovabili. L’introduzione dei convertitori statici ha reso possibile un notevolissimo incremento dello sfruttamento delle fonti di energia rinnovabili: si pensi ad esempio agli inverter per impianti fotovoltaici o ai convertitori back to back per applicazioni eoliche. All’aumentare della potenza di un convertitore aumenta la sua tensione di esercizio: le limitazioni della tensione sopportabile dagli IGBT, che sono i componenti elettronici di potenza di più largo impiego nei convertitori statici, rendono necessarie modifiche strutturali per i convertitori nei casi in cui la tensione superi determinati valori. Tipicamente in media ed alta tensione si impiegano strutture multilivello. Esistono più tipi di configurazioni multilivello: nel presente lavoro è stato fatto un confronto tra le varie strutture esistenti e sono state valutate le possibilità offerte dall’architettura innovativa Modular Multilevel Converter, nota come MMC. Attualmente le strutture più diffuse sono la Diode Clamped e la Cascaded. La prima non è modulare, in quanto richiede un’apposita progettazione in relazione al numero di livelli di tensione. La seconda è modulare, ma richiede alimentazioni separate e indipendenti per ogni modulo. La struttura MMC è modulare e necessita di un’unica alimentazione per il bus DC, ma la presenza dei condensatori richiede particolare attenzione in fase di progettazione della tecnica di controllo, analogamente al caso del Diode Clamped. Un esempio di possibile utilizzo del convertitore MMC riguarda le trasmissioni HVDC, alle quali si sta dedicando un crescente interesse negli ultimi anni.

By-products of the dairy farming as raw material for the biotechnology production of polyhydroxyalkanoates

I Poliidrossialcanoati (PHA) sono poliesteri completamente biodegradabili, prodotti da microrganismi come fonte di energia e di carbonio per la sintesi di nuovo materiale cellulare, utilizzando come substrato materie prime rinnovabili. Questi poliesteri sono considerati potenziali candidati per la sostituzione delle materie plastiche convenzionali. Tuttavia, i più alti costi di produzione dei PHA in confronto a quelli delle materie plastiche derivanti dal petrolio, rappresentano il principale ostacolo per la parziale sostituzione di questi ultimi con i biopolimeri. Gli alti costi sono principalmente dovuti all'utilizzo di colture microbiche pure (in cui sia presente un solo ceppo batterico) e substrati puri e costosi. Nell'ultimo decennio è stato sviluppato un processo di produzione a tre stadi alternativo e potenzialmente a minor costo, basato sull'utilizzo di colture microbiche miste (Mixed Microbials Culture, MMC) e una varietà di substrati organici a costo contenuto o nullo, quali alcuni rifiuti dell’industria agro-alimentare. Il presente studio si è concentrato sulla prima fase del processo di produzione dei PHA da colture miste, la fermentazione acidogenica, utilizzando siero di latte come fonte di carbonio per produrre acidi organici. In particolare questo lavoro ha avuto come obiettivo quello di studiare come diverse condizioni operative utilizzate nella fase di fermentazione acidogenica possono influenzare la concentrazione e il profilo degli acidi organici prodotti. Sono stati valutati anche gli effetti dei diversi profili degli acidi organici sulla fase di selezione della coltura microbica, in termini di capacità di stoccaggio di PHA e composizione polimerica.

Power Converters and Electric Drives for Smart Grid Applications

The present dissertation aims to explore, theoretically and experimentally, the problems and the potential advantages of different types of power converters for “Smart Grid” applications, with particular emphasis on multi-level architectures, which are attracting a rising interest even for industrial requests. The models of the main multilevel architectures (Diode-Clamped and Cascaded) are shown. The best suited modulation strategies to function as a network interface are identified. In particular, the close correlation between PWM (Pulse Width Modulation) approach and SVM (Space Vector Modulation) approach is highlighted. An innovative multilevel topology called MMC (Modular Multilevel Converter) is investigated, and the single-phase, three-phase and "back to back" configurations are analyzed. Specific control techniques that can manage, in an appropriate way, the charge level of the numerous capacitors and handle the power flow in a flexible way are defined and experimentally validated. Another converter that is attracting interest in “Power Conditioning Systems” field is the “Matrix Converter”. Even in this architecture, the output voltage is multilevel. It offers an high quality input current, a bidirectional power flow and has the possibility to control the input power factor (i.e. possibility to participate to active and reactive power regulations). The implemented control system, that allows fast data acquisition for diagnostic purposes, is described and experimentally verified.

Inverters multilivello per il pilotaggio di motori asincroni trifase

In questo lavoro di laurea si presentano le varie famiglie di convertitori multilivello MMC (Modular Multilevel Converter). Questi convertitori sono di ausilio per il condizionamento dei parametri di reti elettriche in media e alta tensione e possono anche essere convenientemente utilizzati nel pilotaggio di motori asincroni trifase. Dopo aver esplicitato i principi di funzionamento, presentato i dispositivi di commutazione, le tipologie conosciute e le rispettive principali tecniche di modulazione, si è presentato il motore asincrono trifase, il suo circuito equivalente e le problematiche di accoppiamento ad un inverter. Successivamente si è simulato un inverter multilivello di tipo Diode-Clamped, con modulazione analogica PWM multiportante, che aziona un motore asincrono commerciale, così da poterne verificare le prestazioni in diversi regimi di velocità.

Eotaxin/CCL11 levels correlate with myocardial fibrosis and mast cell density in native and transplanted rat hearts

Myocardial fibrosis contributes to hemodynamic and cardiac functional alterations commonly observed posttransplantation. Cardiac mast cells (MC) have been linked to fibrosis in posttransplantation hearts. Eotaxin, which has been shown to be involved in fibrogenesis, has been demonstrated to be increased in production in cardiac macrophages. The aim of our study was to correlate myocardial fibrosis during heart transplant rejection in the rat with eotaxin/chemokine [c-c motif] ligand 11 (CCL11) expression, and with various subtypes of infiltrating cardiac MC, namely connective-type MC (CTMC) and mucosa-type MC (MMC).

Macro Monte Carlo for dose calculation of proton beams

Although the Monte Carlo (MC) method allows accurate dose calculation for proton radiotherapy, its usage is limited due to long computing time. In order to gain efficiency, a new macro MC (MMC) technique for proton dose calculations has been developed. The basic principle of the MMC transport is a local to global MC approach. The local simulations using GEANT4 consist of mono-energetic proton pencil beams impinging perpendicularly on slabs of different thicknesses and different materials (water, air, lung, adipose, muscle, spongiosa, cortical bone). During the local simulation multiple scattering, ionization as well as elastic and inelastic interactions have been taken into account and the physical characteristics such as lateral displacement, direction distributions and energy loss have been scored for primary and secondary particles. The scored data from appropriate slabs is then used for the stepwise transport of the protons in the MMC simulation while calculating the energy loss along the path between entrance and exit position. Additionally, based on local simulations the radiation transport of neutrons and the generated ions are included into the MMC simulations for the dose calculations. In order to validate the MMC transport, calculated dose distributions using the MMC transport and GEANT4 have been compared for different mono-energetic proton pencil beams impinging on different phantoms including homogeneous and inhomogeneous situations as well as on a patient CT scan. The agreement of calculated integral depth dose curves is better than 1% or 1 mm for all pencil beams and phantoms considered. For the dose profiles the agreement is within 1% or 1 mm in all phantoms for all energies and depths. The comparison of the dose distribution calculated using either GEANT4 or MMC in the patient also shows an agreement of within 1% or 1 mm. The efficiency of MMC is up to 200 times higher than for GEANT4. The very good level of agreement in the dose comparisons demonstrate that the newly developed MMC transport results in very accurate and efficient dose calculations for proton beams.

High temperature, low cycle fatigue of a hybrid particulate/fiber aluminum metal-matrix composite

The effect of shot particles on the high temperature, low cycle fatigue of a hybrid fiber/particulate metal-matrix composite (MMC) was studied. Two hybrid composites with the general composition A356/35%SiC particle/5%Fiber (one without shot) were tested. It was found that shot particles acting as stress concentrators had little effect on the fatigue performance. It appears that fibers with a high silica content were more likely to debond from the matrix. Final failure of the composite was found to occur preferentially in the matrix. SiC particles fracture progressively during fatigue testing, leading to higher stress in the matrix, and final failure by matrix overload. A continuum mechanics based model was developed to predict failure in fatigue based on the tensile properties of the matrix and particles. By accounting for matrix yielding and recovery, composite creep and particle strength distribution, failure of the composite was predicted.