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METO, AIDA. « Approcci innovativi per studi sui patogeni del cavo orale : modelli di studio in vitro ed ex vivo ». Doctoral thesis, Università degli studi di Modena e Reggio Emilia, 2021. http://hdl.handle.net/11380/1246163.
Texte intégralRésumé :
Negli ultimi anni, sono stati proposti nuovi composti/strumenti per mantenere la salute orale e/o per trattare diversi problemi dentali/parodontali. Come è noto, la carie dentale si pone tra le infezioni più diffuse ed una sua gestione impropria comporta lo sviluppo di malattie rilevanti ed eventualmente all'estrazione dell’elemento dentale. Una vasta letteratura documenta il ruolo patogenetico di diversi microorganismi che sono in grado di persistere nel cavo orale, in quanto capaci di organizzandosi come comunità microbica eterogenea (comprendente batteri, virus e funghi), adesa alle diverse superfici, strettamente racchiusa in una matrice polimerica di origine polisaccaridica. Tale comunità sessile, che se adesa ai denti è detta placca dentale, è notoriamente refrattaria non solo alle comuni procedure di pulizia con collutori e dentifrici/spazzolini, ma anche ai farmaci antimicrobici e alle difese immunitarie dell'ospite. Questo scenario si complica ulteriormente considerando che l’ampio uso di attacchi fissi o rimovibili nei trattamenti ortodontici espande la problematica e la conseguente sfida clinica, essendo tali dispositivi un ulteriore habitat utile per l'adesione microbica, la crescita e la formazione di biofilm. In misura simile, i pazienti con impianti dentali possono sviluppare localmente malattie legate alla produzione di biofilm impianto-associato, consentendo la progressione clinica verso quadri di perimucosite o perimplantite infettiva. Da qui, sorge la necessità di strumenti/composti innovativi per facilitare la rimozione di microrganismi potenzialmente patogeni e il mantenimento dell'omeostasi del cavo orale. Oltre ai patogeni orali più noti, tra cui il gruppo Streptococcus mutans e il "complesso rosso" dei bacilli anaerobi Gram-negativi, anche Candida albicans (C. albicans), Staphylococcus aureus (S. aureus) e Pseudomonas aeruginosa (P. aeruginosa) possono essere agenti eziologici di malattie orali. Il primo germe, spesso ospitato come commensale delle mucose sane, è il principale patogeno fungino coinvolto nella mucosite orale. Gli altri due sono patogeni molto subdoli, responsabili di malattie ad ampio spettro; considerati i loro numerosi fattori di virulenza e l’ampia farmaco-resistenza, S. aureus e P. aeruginosa sono ampiamente utilizzati per studi in vitro come preziosi prototipi di patogeni Gram-positivi e Gram-negativi. Lo scopo della presente tesi era di valutare in vitro ed ex vivo l'efficacia antimicrobica e antibiofilm di approcci innovativi contro i patogeni orali. Questa tesi ha fornito prove in vitro ed ex vivo sull'efficacia antimicrobica di composti nuovi e tradizionali per la cura e l’igiene del cavo orale, da cui possono derivare in prospettiva scelte più razionali e consapevoli. Ad esempio, un nuovo utilizzo del prodotto endodontico Cupral potrebbe essere proposto nelle pratiche di igiene quotidiana, così come potrebbe essere privilegiato il trattamento delle peri-implantiti con il sistema Bic-40, vista la sua particolare efficacia nella pulizia e nella decontaminazione di superfici lisce e ruvide in titanio, senza influire sulla vitalità delle cellule staminali dell’ospite. Inoltre, il nostro lavoro ha aggiunto nuove conoscenze sulle proprietà antimicrobiche di un composto naturale come la propoli e sui suoi possibili meccanismi d'azione, offrendo nuove opportunità nella ricerca di molecole antimicrobiche alternative. Infine, abbiamo dimostrato che il dentifricio e la gomma Biorepair Peribioma possono influenzare profondamente il comportamento dei microorganismi del cavo orale, a favore di condizioni utili al mantenimento dello stato di salute di questo distretto anatomico. Questo lavoro ha fornito nuove evidenze su come contrastare i patogeni, particolarmente se produttori di biofilm; facilitando il disegno di strategie mirate per la prevenzione e/o il trattamento delle infezioni dentali e orali associate al biofilm.During recent years, novel compounds/tools are being proposed to maintain oral health and/or to treat dental/periodontal problems. As well known, dental caries are among the most diffused infections and their improper management turns towards relevant disease(s) and eventually tooth extraction. Extensive literature documents the pathogenic role of certain microorganisms and their ability to persist in the oral cavity, as a complex microbial community, including bacteria, viruses and fungi, tightly enclosed in a polymeric matrix of polysaccharide origin. Such sessile community, and particularly dental plaque, the first deeply studied human-associated biofilm, is notoriously refractory not only to common cleaning procedures by mouthwashes and tooth-pastes/brushes, but also to antimicrobial drugs and host immune defenses. This scenario becomes further complicated considering that the widely diffused orthodontic treatments, with fixed or removal brackets, extend the clinical challenge, being such devices an additional good habitat for microbial adhesion, growth and biofilm formation. To a similar extent, patients with dental implants may locally develop biofilm-related diseases, allowing clinical progression toward pathogen-related peri-mucositis or peri-implantitis. From here, the need arises for innovative tools/compounds to facilitate microbial removal and maintenance of oral cavity homeostasis. Besides the most investigated oral pathogens, including Streptococcus mutans-group and the “red complex” Gram-negative anaerobe bacilli, also Candida albicans (C. albicans), Staphylococcus aureus (S. aureus) and Pseudomonas aeruginosa (P. aeruginosa) may occur as causative agent of oral diseases. The first, often harbored as commensal of healthy mucosae, is the main fungal pathogen involved in oral mucositis. The latter two are subtle pathogens, responsible of wide-spectrum diseases; they are being extensively used for in vitro studies, because of their numerous virulence factors and wide-spectrum antimicrobial resistance. The aim of the present thesis was to evaluate in vitro and ex vivo, the antimicrobial and antibiofilm efficacy of innovative approaches against oral pathogens. Our data provided in vitro and ex vivo evidence on the antimicrobial efficacy of several dental-care compounds. A novel use of the endodontic product Cupral could be proposed in daily hygiene practices. The Bic-40 treatment was shown as the best approach in cleaning smooth and rough titanium surfaces (without altering their properties); importantly, its device-decontamination efficacy did not affect the biological properties of reparative stem cells. Furthermore, our work added new insights on the anti-microbial properties of a natural compound, such as propolis, and on its possible mechanisms of action. At last, we showed that the Biorepair Peribioma toothpaste and gum deeply affected oral microorganisms’ behavior, drastically impairing their ability to contaminate and produce plaque onto orthodontic devices; interestingly, replacement by beneficial microorganisms was observed. The overall take-home message from this research is that basic science may greatly increase our knowledge on how to counteract biofilm-producing pathogens; in turn, this will facilitate prevention and/or treatment of dental and oral biofilm-associated infections, making a huge difference in terms of health promotion.
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BAZZINI, CHIARA. « STUDY OF MOLECULAR MECHANISMS AND NEW STRATEGIES AGAINST A CYTOTOXICITY AND NEUROINFLAMMATION IN EX VIVO CELLULAR MODELS FROM ALZHEIMER’S DISEASE PATIENTS ». Doctoral thesis, Università degli Studi di Milano-Bicocca, 2021. http://hdl.handle.net/10281/306480.
Texte intégralRésumé :
La malattia di Alzheimer (AD) rappresenta una delle principali problematiche per la salute pubblica ed è stata identificata come una priorità per la ricerca. Le due caratteristiche patologiche fondamentali della malattia sono le placche amiloidi e i grovigli neuro fibrillari che sono alla base della neuroinfiammazione e del deterioramento cognitivo.Le forme solubili degli oligomeri sono la specie più tossica della β-amiloide (Aβ) e interagiscono con diverse chinasi proteiche coinvolte nella trasduzione del segnale intracellulare come Ras/MAPK e PI3K/AKT che regolano molti processi cellulari e funzioni cognitive, e alcuni meccanismi molecolari coinvolti nella degenerazione neuronale, come l'iperfosforilazione di tau e l'eccitotossicità del glutammato. Negli ultimi anni molta attenzione è stata focalizzata sull'utilizzo di composti naturali come agenti neuroprotettivi. Il luppolo (Humulus Lupulus) contiene flavonoidi, molecole aromatiche che hanno proprietà antiossidanti e antinfiammatorie. È stato dimostrato che l'estratto di luppolo ha effetti antiaggreganti sull’Aβ e sembra impedire la sua produzione nelle cellule in coltura. L'accumulo di Aβ induce anche l'attivazione della proteina 3 del recettore Nod-like receptor 3 (NLRP3) dell’inflammosoma e il conseguente rilascio di citochine proinfiammatorie, il quale svolge un ruolo fondamentale nella neuroinfiammazione associata all'AD. NLRP3 attivato induce la produzione e il rilascio di mediatori infiammatori, tra cui i complessi proteici ASC (ASC specks), IL-1β e IL-18, che facilitano la deposizione di Aβ in un ciclo che si auto alimenta. Impedire l’assemblaggio e l'attivazione del complesso dell’inflammosoma potrebbe essere una possibile strategia per la terapia dell'AD.
L'obiettivo generale di questo studio è quello di indagare i meccanismi molecolari coinvolti nelle malattie neurodegenerative e nella neuroinfiammazione utilizzando modelli cellulari periferici ex vivo di AD.Al fine di caratterizzare le interazioni Aβ e vie di trasduzione del segnale MAPK e AKT, abbiamo utilizzato fibroblasti di pazienti AD sporadici con diversa gravità della malattia. Per valutare i meccanismi molecolari che potrebbero prevenire o modulare la tossicità indotta da Aβ, sono stati studiati anche i potenziali effetti citoprotettivi dell'estratto di luppolo e il relativo signaling intracellulare. Inoltre, è stato dato particolare interesse alla via di attivazione del NLRP3-infiammasoma. Abbiamo studiato il coinvolgimento dell'attivazione di NLRP3 sulle vie MAPK e AKT e sui loro bersagli a valle, utilizzando una combinazione di studi in vitro e di campioni ottenuti dai pazienti. In particolare, abbiamo utilizzato monociti umani THP-1 di derivazione macrofagica e monociti derivati da cellule mononucleate del sangue periferico (PBMC) di soggetti sani (HC) e pazienti affetti da AD, per analizzare la modulazione autofagica e gli effetti della Stavudina (D4T), un inibitore nucleosidico della trascrittasi inversa, che riduce l'attivazione dell'inflammosoma bloccando il recettore purinergico P2X7R. Inoltre, abbiamo analizzato il pathway di attivazione dell'inflammosoma NLRP3 e il ruolo di CRID3 un inibitore selettivo, per confrontare gli effetti dell’inibizione dell’inflammosoma attraverso due pathway differenti. I monociti derivati da HC e AD sono stati differenziati in cellule microglia-like (MDMIs) e caratterizzati per l'espressione di proteine intracellulari e di superficie tipiche delle cellule mieloidi. Funzioni tipiche della microglia come il rilascio di citochine infiammatorie, la fagocitosi e la degradazione sono state valutate anche in seguito all'esposizione di attivatori dell'inflammosoma con o senza CRID3. MDMIs riflettono molte caratteristiche della microglia e sono un modello cellulare utile per comprendere la patogenesi dell'AD, identificare i target terapeutici e consentire lo screening farmacologico su larga scala dei nuovi composti per uso terapeutico.Alzheimer's disease (AD) is a major public health concern and has been identified as a priority for research in Life Science. The two core pathological hallmarks of AD are extracellular amyloid plaques and intracellular neurofibrillary tangles which underlie microglial and neuronal damage, neuroinflammation and cognitive impairment. Soluble oligomers are the most toxic species of β-amyloid (Aβ) and interact with several protein kinases such as Ras/MAPK and PI3K/AKT pathways, which regulate many cellular processes and cognitive functions. These pathways mediate Aβ toxicity, regulating some molecular mechanisms involved in neuronal degeneration such as cytoskeletal impairment, glutamate excitotoxicity and neuroinflammation. In the last years much attention has been focused on the potential role of natural compounds as neuroprotective agents. Hop (Humulus Lupulus) contains flavonoids, aromatic molecules which have antioxidant, anti-inflammatory and anti-atherogenic properties. In fact, hop extract has anti-aggregating effects on Aβ, and it seems to prevent its production in cultured cells. Aβ induces also the activation of the pattern recognition receptor Nod-like receptor protein 3 (NLRP3) inflammasome complex in microglia and the consequent release of proinflammatory cytokines, playing a pivotal role in AD-associated neuroinflammation. NLRP3 activation results in the release of inflammatory mediators, including ASC protein complexes (ASC specks), IL-1β and IL-18, that facilitate Aβ deposition and neuroinflammation in a self-feeding pathogenic loop. Since specific therapeutical strategies are still lacking, the dampening of the inflammasome assembly and activation could be a new strategy for AD. The overall focus of this study is to investigate molecular mechanisms involved in neurodegenerative diseases and in neuroinflammation, using peripheral ex vivo cellular models from AD, to check new potential therapeutical targets. In order to characterize the complex interactions among Aβ, MAPK and AKT signaling, we used fibroblasts from sporadic AD patients with different disease severity. To evaluate any molecular mechanisms that could prevent or modulate Aβ-induced toxicity, the potential cytoprotective effects of Hop extract and related intracellular signaling were also investigated. Fibroblasts provide a useful cellular model for studying AD, since they could be differentiated into patient-specific neural cell lines, using iPSC technologies. Moreover, particular interest was given to NLRP3-inflammasome activation pathway. We investigated the involvement of NLRP3 inflammasome activation on intracellular pathways and their downstream targets, using a combination of in vitro studies and patient-derived samples. In particular, we used macrophage-derived THP-1 human monocytes and peripheral blood mononuclear cells (PBMC)-derived monocytes from healthy control (HC) subjects and AD patients, to analyse phagocytosis, autophagy and apoptosis modulation and the effects of the nucleoside reverse transcriptase inhibitor Stavudine (D4T), that reduces NLRP3 inflammasome activation blocking the purinergic receptor P2X7R. Furthermore, we analyzed the NLRP3 inflammasome pathway and the role of the selective NLRP3 inhibitor CRID3, to compare the effects of inflammasome inhibition through two different mechanisms. At this purpose, HC and AD-derived monocytes were differentiated into microglia-like cells (MDMIs) and characterized for myeloid surface and intracellular proteins expression. Key microglia functions such as inflammatory cytokines release, Aβ phagocytosis and degradation were evaluated upon exposure to NLRP3 inflammasome activators with or without CRID3. MDMIs reflected many features of microglia and, as fibroblasts-derived iPSCs, they are attractive cellular models helpful to understand AD pathogenesis, identify therapeutic targets and allow large-scale drug screening of the novel therapeutic candidates.
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BASTIOLI, GUENDALINA. « Studio dei meccanismi neurotossici coinvolti nella neurodegenerazione indotta da mutazione Lrrk2 o da α-sinucleina in modelli ex-vivo o in vitro di malattia di Parkison ». Doctoral thesis, Università Politecnica delle Marche, 2018. http://hdl.handle.net/11566/253148.
Texte intégralRésumé :
Studio dei meccanismi neurotossici coinvolti nella neurodegenerazione indotta da mutazione Lrrk2 o da α-sinucleina in modelli ex-vivo o in vitro di malattia di Parkison
La malattia di Parkinson (PD) è una malattia neurodegenerativa multifattoriale caratterizzata dalla degenerazione dei neuroni dopaminergici della substantia nigra. Tra le anomalie genetiche identificate nella malattia di Parkinson (PD), le mutazioni del gene della ripetizione della leucina kinase2 (Lrrk2), come la mutazione missenso G2019S legata all'aumento dell'attività della chinasi, sono le più comuni. Mentre il complesso ruolo di Lrrk2 non è stato completamente chiarito, sono state riportate evidenze che l'attività della chinasi mutata influenza la trasmissione sinaptica. L'iperattivazione del dominio della chinasi di Lrrk2 potrebbe rappresentare un fattore predisponente sia per il rilascio glutammatergico striatale potenziato sia per la vulnerabilità mitocondriale ai fattori ambientali osservati nel PD. Per indagare su possibili alterazioni della suscettibilità striatale alla disfunzione mitocondriale, abbiamo eseguito registrazioni elettrofisiologiche dal nucleo striato di un modello di PD Lrrk2 G2019S, e inoltre abbiamo indagato su possibili alterazioni precoci della neurotrasmissione prodotta dalla mutazione Lrrk2 di G2019S nel PD. Un altro fattore genetico è la presenza di inclusioni intracellulari denominate corpi di Lewy costituiti da aggregati α-Synuclein (α-Syn). Diversi studi hanno dimostrato che l'accumulo di α-Syn nei neuroni dopaminergici umani riduce l'attività del complesso I mitocondriale, aumenta la produzione di specie reattive dell'ossigeno e provoca cambiamenti dei livelli di Ca2+. Lo scambiatore Na+/Ca2+ (NCX) è un importante regolatore delle concentrazioni di Ca2+ citoplasmatiche e mitocondriali. Abbiamo quindi studiato il possibile ruolo svolto da NCX nella tossicità mitocondriale in un modello in vitro del PD precoce. Abbiamo trovato che in G2019S-Lrrk2 (KI), mentre la trasmissione glutamatergica spontanea basale, facilitazione sinaptica e rapporti NMDA / AMPA erano invariati, la stimolazione del recettore DA D2 da parte del quinpirolo ha ridotto le correnti postsinaptiche eccitatorie spontanee ed evocate (EPSC). E anche che la stimolazione del recettore D2 ha avuto un effetto neuroprotettivo sulla funzione mitocondriale. Mentre l'inibizione di mNCX esercita un effetto protettivo sul danno neuronale in un modello di PD precoce.Studio dei meccanismi neurotossici coinvolti nella neurodegenerazione indotta da mutazione Lrrk2 o da α-sinucleina in modelli ex-vivo o in vitro di malattia di Parkison La malattia di Parkinson (PD) è una malattia neurodegenerativa multifattoriale caratterizzata dalla degenerazione dei neuroni dopaminergici della substantia nigra. Tra le anomalie genetiche identificate nella malattia di Parkinson (PD), le mutazioni del gene della ripetizione della leucina kinase2 (Lrrk2), come la mutazione missenso G2019S legata all'aumento dell'attività della chinasi, sono le più comuni. Mentre il complesso ruolo di Lrrk2 non è stato completamente chiarito, sono state riportate evidenze che l'attività della chinasi mutata influenza la trasmissione sinaptica. L'iperattivazione del dominio della chinasi di Lrrk2 potrebbe rappresentare un fattore predisponente sia per il rilascio glutammatergico striatale potenziato sia per la vulnerabilità mitocondriale ai fattori ambientali osservati nel PD. Per indagare su possibili alterazioni della suscettibilità striatale alla disfunzione mitocondriale, abbiamo eseguito registrazioni elettrofisiologiche dal nucleo striato di un modello di PD Lrrk2 G2019S, e inoltre abbiamo indagato su possibili alterazioni precoci della neurotrasmissione prodotta dalla mutazione Lrrk2 di G2019S nel PD. Un altro fattore genetico è la presenza di inclusioni intracellulari denominate corpi di Lewy costituiti da aggregati α-Synuclein (α-Syn). Diversi studi hanno dimostrato che l'accumulo di α-Syn nei neuroni dopaminergici umani riduce l'attività del complesso I mitocondriale, aumenta la produzione di specie reattive dell'ossigeno e provoca cambiamenti dei livelli di Ca2+. Lo scambiatore Na+/Ca2+ (NCX) è un importante regolatore delle concentrazioni di Ca2+ citoplasmatiche e mitocondriali. Abbiamo quindi studiato il possibile ruolo svolto da NCX nella tossicità mitocondriale in un modello in vitro del PD precoce. Abbiamo trovato che in G2019S-Lrrk2 (KI), mentre la trasmissione glutamatergica spontanea basale, facilitazione sinaptica e rapporti NMDA / AMPA erano invariati, la stimolazione del recettore DA D2 da parte del quinpirolo ha ridotto le correnti postsinaptiche eccitatorie spontanee ed evocate (EPSC). E anche che la stimolazione del recettore D2 ha avuto un effetto neuroprotettivo sulla funzione mitocondriale. Mentre l'inibizione di mNCX esercita un effetto protettivo sul danno neuronale in un modello di PD precoce.
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Calo', R. « STUDIO DEI MECCANISMI DI DANNO DA RAGGI UVA E UVB E DEGLI EFFETTI PROTETTIVI DA PARTE DI COMPOSTI POLIFENOLICI IN SISTEMI CELLULARI E MODELLI EX VIVO DI CUTE UMANA ». Doctoral thesis, Università degli Studi di Milano, 2014. http://hdl.handle.net/2434/244829.
Texte intégralRésumé :
Sun radiation consists of several spectrum regions, depending on the wavelengths, such as ultraviolet, visible and infrared portions. The ultraviolet rays (UV) are associated with both positive and negative effects on humans’ health. Ultraviolet light is used in the process of disinfection, it shows immunoregolatory activity and it stimulates vitamin D and serotonin production. It is well known that artificial sources of UVR are employed in the health field for sterilization procedures and for therapeutical purposes, such as treatment of dermatological pathologies like psoriasis, vitiligo and icterus neonatorum, as well as for aesthetic purposes (sunbed). In the last decade, besides these positive effects, UV side effects on skin have been demonstrated by different studies which correlated the intense and prolonged exposure to UV light with skin cancer development.
Based on wavelength, UV spectrum can be divided into three segments: UVA (320-400 nm), UVB (280-320 nm) and UVC (100-280 nm). Radiation in the UVC range, considered to be the most cytotoxic and harmful, is largely absorbed by the stratospheric ozone layer, so UV regions mainly involved in photocancerogenesis development are considered to be ultraviolet radiation A (UVA) and ultraviolet radiation B (UVB). The amount and the UVA/UVB ratio that reach the Earth’s surface is influenced by a lot of environmental factors as latitude, seasons, weather/atmospheric conditions and the time of day.
UVA is by far the most abundant solar UV radiation that reaches the Earth (about 90-95% of total UV radiation), penetrates the human epidermis down to the proliferative basal cells and even further to the derma and mediate biological events generating reactive oxygen species (ROS) in cells. ROS oxide other cellular constituents, particularly carbohydrates, lipids, proteins and DNA. Interactions between ROS and DNA induce formation of single strand breaks (SSBs), DNA-proteins crosslink and oxidized bases. The most abundant oxidized base is the guanine that produces the 8-oxoguanine, considered as promoter of carcinogenesis.
UVB represents only 5% of total UV radiation that reaches the Earth. Besides it acts mainly at the epidermis basal layer of the skin, it is considered extremely damaging because of its high energy. UVB photons are directly absorbed by DNA and cause the formation of cyclobutane pyrimide dimers (CPDs) and pyrimidine (6-4) pyrimidone photoproducts (6-4PPs), which in turn can lead to apoptotic events or carcinogenesis development. Also tryptophan and tyrosine are modified by UVB inducing the alteration of structure and function of proteins. Moreover, UVB is able to produce reactive oxygen species (ROS) and reactive nitric species (RNS).
Cells have developed defense mechanisms and endogenous repair systems in order to reduce genotoxic damage UV-induced: complexes of antioxidant enzymes which take advantage of the presence of a metal to inactivate reactive oxygen species, and DNA repair systems like the base excision repair system (BER), used for oxidized bases, and the nucleotide excision repair (NER), used to repair photolesions like CPD and 6-4 PP. Recently, several molecules have been studied for their ability to give a contribution to these antioxidant defenses. For these reasons, there is a considerable interest in the concept of the use of phytochemicals and micronutrients present in the diet such as carotenoids, vitamin E and C, and polyphenols. This last group of compounds are well known for their several biological properties, such as their antioxidant activity, their ability to enhance the activity of DNA repair systems and also their skills in inflammatory and apoptotic events modulations.
Several epidemiological studies have demonstrated their biological effects and their efficiency in the prevention and treatment of several chronic diseases like cardiovascular, respiratory, neurodegenerative and inflammatory diseases and cancer.
So, in view of these reasons, the aim of my study was double: first, to confirm literature data regarding the different mechanisms used by UVA and UVB rays to cause damage in various models, then to investigate whether different plant-derivatives compounds, all belonging to the pholiphenols category, were able to prevent UVA- and UVB-induced damage.
I reproduced the experiments on in vitro and ex vivo models. In vitro models consist of two human keratinocytes cell lines (HaCaT and NCTC 2544 cells), generally used for routine toxicological tests and photogenotoxic evaluations. Both cell lines are non tumorigenic, but showed a different degree of differentiation, higher in HaCaT cells compared to NCTC 2544. The ex vivo model consist of a three-dimensional model of organotypic human skin cultures useful to reproduce the physiological conditions. I tested the efficiency of three compounds: a water soluble extract of Bilberry only in the in vitro models (Vaccinium Myrtillus extract, rich in polyphenols and considered to be the plant with the highest content of anthocyanins), a Thymus Vulgaris leaf extract (Thyme specie) and the synthetic Thymol (its major component), used in comparable dosages, in both models. All experimental models were pretreated in serum free medium for 1 hour with each compound and then irradiated with UVA or UVB. Control samples were treated in the same way, but not UV exposed.
In order to confirm mechanisms of UV damage and to compare results obtained in the experimental models, I performed several tests, each with a specific endpoint. I evaluated the intracellular redox status, quantifying the ROS formed and the lipid peroxidation (malondialdeide levels, MDA), immediately after the end of UVA and UVB exposure and only in the in vitro models; after, I performed some genotoxic tests (the alkaline comet test to detect single and double strand breaks in single cells, the immunostaining of the histone H2AX phosphorilated to detect only double strand breaks and the micronucleous test to detect alterations to mitotic apparatus or to chromosomes); finally I investigated effects of rays on apoptotic events, using the Annexin V test and evaluating the alteration of mitochondrial membrane potential UV-induced. After, using this same assays, I tested the protective effect of Vaccinium Myrtillus extract, thymol and Thymus Vulgaris L. extract. Vaccinium Myrtillus’ effect was evaluated only in the in vitro models, the protection of thymol and Thymus Vulgaris L. extract in both models (in vitro and ex vivo).
Results obtained confirmed the different machanisms of action of UVA and UVB in all models. Particularly, confirming the different mechanisms of damage used by UVA and UVB rays. My results showed the more oxidant UVA effect and the more genotoxic and apoptotic UVB effect.
Three natural compounds showed their different protective effect against UVA- and UVB- induced damage, in in vitro models. Moreover, thymol and Thymus Vulgaris L. extract reduced damage UV-related both in the NCTC 2544 and HaCaT cell lines but also in the ex vivo model.
Vaccinium Myrtillus extract, thymol and Thymus Vulgaris L. extract reduced, to a different extent, UVA-caused damage, on account of their antioxidant properties. Compounds revealed their ability to reduce also UVB-induced damage. The efficiency against UVB damage was lower compared to the one against UVA rays. Probably the protection was related with the ability of pholyphenols, and because of my compounds, to repair DNA damage UVB-induced increasing the expression of genes involved in NER system (specifically involved in UVB-induced damage repair).
Vaccinium Myrtillus, thymol and Thymus Vulgaris L. extract showed also their protection in the apoptotic assays, avoiding the increase of extremely damaged cells which could lead to mutagenesis development.
Results obtained in my thesis activity should be considered as preliminary data useful to investigate, in detail, mechanisms used by the three natural compounds to prevent genotoxic damage UVA- and UVB-induced. Moreover, it should be very interesting to investigate the bioavailability and the permeability of tested compounds in order to use them as food supplements for a diet enriched in antioxidants (systemic effect) or in sunscreens (topical effect).
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Saunders, John. « Ex vivo modelling of oesophago-gastric cancer ». Thesis, University of Nottingham, 2017. http://eprints.nottingham.ac.uk/47574/.
Texte intégralRésumé :
Introduction The response to neoadjuvant chemotherapy in oesophago-gastric (OG) cancer is only 40%, so over half of the patient’s disease will progress, whilst they also suffer the toxic chemotherapy side-effects. A model to predict chemotherapy response would provide a marked clinical benefit, by enabling personalised treatment of OG cancer. Methods Live chemo-naïve tumour biopsies were obtained following informed consent at staging endoscopy, before patients underwent their routine neoadjuvant chemotherapy. Tumour cells from the endoscopic biopsies were expanded, using an in vitro feeder layer system and supplemented medium. With ethics committee approval and under Home Office guidance, these individual patient cancer cells were engrafted into immuno-compromised mice, where they formed representative tumour xenografts. Primary patient tissue, the corresponding individual patient cancer cells and their matching xenografts were analysed using immunohistochemistry, demonstrating that the in vitro and in vivo cells had retained the characteristics of the original patient’s oesophageal adenocarcinoma. To model the human tumour micro-environment (TME), a three dimensional tumour growth assay (3D-TGA) was developed, whereby the individual patient’s primary tumour cells were grown as 3D cancer cell clusters. This was performed by seeding individual patient’s primary tumour cells within a biological basement membrane extract, rich in extracellular matrix (ECM) components, with and without human mesenchymal stem cells to provide stromal support. The individual patient cancer clusters in the 3D-TGA were subjected to detailed chemotherapeutic assessment, to quantify their chemo-sensitivity to the standard chemotherapy which was administered to the patient in the clinic. This 3D-TGA predicted chemo-sensitivity was then compared with the patient’s actual clinical chemotherapy response, as measured by the histological tumour regression grade, which directly relates to prognosis. In combination with standard platinum-based chemotherapy, the 3D-TGA was assessed as a platform for evaluating new chemotherapeutics: the novel emerging HDAC inhibitor Panobinostat, and the phosphodiesterase type 5 inhibitor Vardenafil, which has recently been shown to be active against cancer stroma, were evaluated. Results Individual patient tumours were grown from primary endoscopic biopsy tissue in over half of samples obtained within a clinically applicable timescale of 2-4 weeks. Incorporating human mesenchymal cells into the 3D-TGA significantly changed the growth and drug resistance profiles (p < 0.005). This 3D-TGA chemo-response in the presence of stroma reflected the clinical chemo-sensitivity, with an accurate correlation between the 3D-TGA predicted chemo-resistance and actual clinical response for the patients evaluated. As well as predicting potential chemo-sensitivity for individual patients, the method allows individual drugs and combinations to be evaluated, trends in chemo-sensitivity between patients to be appraised, and analysis of the effect of the TME on tumour growth and chemotherapy resistance. Combination with Panobinostat enhanced response and proved efficacious in otherwise chemo-resistant tumours. Addition of PDE5i demonstrated an overall significantly enhanced chemotherapeutic response (p=0.003), and consequently provided efficacy in 60% of the otherwise chemo-resistant tumours. Discussion The novel method of growing individual patient OG cancers, using a 3D model with specific components of the tumour micro-environment in particular ECM and mesenchymal cells, provides a clinically-relevant oesophageal cancer model with application for chemo-sensitivity testing. Mesenchymal cells have a significant effect enhancing chemotherapy drug resistance in OG cancer, and this 3D model allowed identification of patients in which stromal targeting using PDE5i provided a significant reduction in chemotherapy drug resistance. In these patients, addition of PDE5i to routine chemotherapy could result in a marked change in the clinical efficacy of their chemotherapy regimen. The 3D model’s chemo-response accurately reflects individual patients’ clinical chemo-sensitivity and so this research has direct clinical application: if this assay proves to be predictive across a wider patient population, then following clinical trials, it could potentially be used to routinely guide individual patient therapy in the clinic, with administration of tailored chemotherapy for individual patient benefit.
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Strobel, Steffen Peter. « Die ex-vivo-Perfusion hDAF-transgener Kaninchennieren mit Humanblut : ein Modell für die humane Xenotransplantation ». Ulm : Universität Ulm, Medizinische Fakultät, 2004. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB11482174.
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Rez, Mohammed Fayez al. « Modelling and measurement of the O2-concentration for the ex vivo cultivation of cells and tissues ». Dresden TUDpress, 2007. http://deposit.d-nb.de/cgi-bin/dokserv?id=2960243&prov=M&dok_var=1&dok_ext=htm.
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Chambin, Odile. « Validation d'un modele d'absorption percutanee ex vivo : approche correlative avec des parametres in vivo ». Dijon, 1995. http://www.theses.fr/1995DIJOPE02.
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Steckmeier, Stephanie. « Experimentelle Evaluation der endovenösen Radiofrequenzobliteration und Lasertherapie an einem neuen ex-vivo Modell ». Diss., lmu, 2006. http://nbn-resolving.de/urn:nbn:de:bvb:19-61465.
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Gassert, Felix [Verfasser]. « Geweberegeneration in einem bovinen ex vivo-Knorpeltrauma-Modell : Analysen therapeutischer Effekte / Felix Gassert ». Ulm : Universität Ulm, 2020. http://d-nb.info/1217715371/34.
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Drews, Tobias [Verfasser]. « Genauigkeit der computerunterstützten Lungenrundherdvolumetrie an künstlichen pulmonalen Läsionen im Ex-vivo-Modell / Tobias Drews ». Kiel : Universitätsbibliothek Kiel, 2009. http://d-nb.info/1019867647/34.
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Bein, Matthias. « Molekulare und immunelektronenmikroskopische Untersuchungen zur Expression von sekretorischen Aspartatproteinasen in einem ex vivo Modell der vaginalen Kandidose und in vivo ». Diss., lmu, 2005. http://nbn-resolving.de/urn:nbn:de:bvb:19-40728.
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Manders, Alice. « Entwicklung eines Sehnendefekt-Modells beim Schaf zur Simulation von Core Lesions - Literaturreview und Methodenentwicklung ex-vivo ». Doctoral thesis, Universitätsbibliothek Leipzig, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-114904.
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Anlass der vorliegenden Arbeit war die Suche nach einem geeigneten Sehnendefekt-Modell, das die Untersuchung der Wirkung moderner Therapieansätze unter Standardbedingungen ermöglicht. Die Auswertung der Literatur zeigte, dass eine große Anzahl an Sehnendefekt-Modellen mit sehr unterschiedlichen Fragestellungen sowohl an Großtieren, Kleintieren als auch Labortieren eingesetzt wurde. In der vorliegenden Arbeit wurden bekannte Sehnendefekt-Modelle mit besonderem Augenmerk auf die verwendete Methodik und das damit induzierte Schadmuster untersucht. Die umfassende Literaturauswertung mit präziser pathomorphologischer Charakterisierung der Defekte diente als entscheidende Grundlage für die Entwicklung des eigenen Tiermodells.
Beim hier vorgestellten Schafmodell handelt es sich um ein Core Lesion- Modell. Es simuliert die am häufigsten beim Pferd auftretende Sehnenerkrankung und bietet die Möglichkeit der direkten intraläsionalen Injektion eines Therapeutikums. Die Core Lesion stellt ein abgeschlossenes Kompartiment dar, so dass keine Trägermaterialien nötig sind, um ein appliziertes Therapeutikum am Wirkort zu binden. Verschiedene chirurgische Zugänge und Zielsehnen wurden beim Schafmodell untersucht. Als geeignet für ein Core Lesion- Modell erwiesen sich beim Schaf die tiefe Beugesehne distal des Karpalgelenks sowie die oberflächliche Beugesehne im Bereich des Tendo calcaneus communis. Für die Induktion der Läsion wurden in Anlehnung an die von LITTLE und SCHRAMME (2006) bzw. SCHRAMME et al. (2010a) beim Pferd gezeigte Methodik unterschiedliche chirurgische Instrumente verwendet. Dabei wurden der Einsatz einer Knochenmark-Extraktionsnadel sowie verschiedene manuell oder elektrisch betriebene arthroskopische Klingen und Fräsköpfe hinsichtlich ihrer Verwendbarkeit sowie des durch sie verursachten Schadmusters miteinander verglichen. Ein manueller Instrumenteneinsatz führte zu deutlich milderen Schadmustern. Dabei kam es durch die Verwendung des Stiletts einer Knochenmark-Extraktionsnadel in einigen Bereichen zu scharfen Faserdurchtrennungen, in anderen Bereichen wurden die Kollagenfasern nur stumpf auseinander gedehnt. Der Einsatz arthroskopischer Klingen und Fräsköpfe beim Schafmodell ist nur eingeschränkt möglich. Durch die geringe Sehnengröße stehen nur sehr wenige Instrumente mit einem entsprechend kleinen Durchmesser zur Verfügung. Ein Round Burr konnte unter experimentellen Bedingungen eingesetzt werden und führte zu einer hochgradigen Schädigung des kompletten Sehnenquerschnitts. Dabei wurden die Fasern aus ihrer ursprünglichen Orientierung heraus gerissen, zumeist aber nicht vom umgebenden Gewebe abgetrennt. Ein Synovial Resector führte hingegen zu einer scharfen Faserdurchtrennung und dadurch zu einem deutlich abgegrenzten Defektbereich. Weitere Einzelheiten wie die resultierende Einblutung und das Einwandern verschiedener Entzündungszell-Spezies müssen in-vivo untersucht werden, um eine klare Empfehlung für den Einsatz der verschiedenen Instrumente formulieren zu können. Die Auswertung der vorhandenen Sehnendefekt-Modelle sowie die eigenen Ergebnisse führten zu dem Schluss, dass eine Kombination verschiedener Methoden sinnvoll sein könnte.
Die Arbeit beschreibt ein sicheres, praktikables Großtiermodell für die Simulation von Core Lesions. Das Modell kann zunächst im Tierversuch eingesetzt werden, um die nach Defektinduktion ablaufenden pathophysiologischen Prozesse zu charakterisieren. Dann steht mit dem Schafmodell ein zeitgemäßes Modell für die Untersuchung verschiedener Therapiekonzepte zur Verfügung, das für die Pferdemedizin eingesetzt werden kann, sich aber auch für Untersuchungen mit humanmedizinischem Hintergrund vielversprechend zeigt. Das Modell stellt damit ein wichtiges Bindeglied zwischen Grundlagenforschung und dem klinischen Einsatz moderner Therapiekonzepte dar.
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Whitford, C. « Biomechanical properties of the ocular globe based on ex vivo testing and multiscale numerical modelling ». Thesis, University of Liverpool, 2016. http://livrepository.liverpool.ac.uk/3004572/.
Texte intégralRésumé :
The present study is the culmination of quantifying and qualitative experimental and numerical research representing biomechanical behaviour of the human eye. A new experimental technique for testing intact eye globes in a form that is representative of in vivo conditions is developed which is suitable for determining the material properties of the complete outer ocular tunic. A test rig has been developed to provide closed-loop control of either applied intraocular pressure or resulting apical displacement, measurement of displacements across the external surface of eye globe using high-resolution digital cameras and digital image correlation software, prevention of rigid-body motion and protection of ocular surface from environmental drying. The method has been demonstrated on one human and i one porcine eye globe, which were cyclically loaded. Finite element models based on specimen specific tomography, free from rotational symmetry, were used along with experimental pressure-displacement data in an inverse analysis process to derive the mechanical properties of tissue in different regions of the eye’s outer tunic. The test method enabled monitoring of mechanical response to intraocular pressure variation across the surface of the eye globe. For the two eyes tested, the method showed a gradual change in the sclera’s stiffness from a maximum at the limbus to a minimum at the posterior pole, while in the cornea the stiffness was highest at the centre and lowest in the peripheral zone. Further, for both the sclera and cornea, the load-displacement behaviour did not vary significantly between loading cycles. The first methodology capable of mechanically testing intact eye globes, with applied loads and boundary conditions that closely represent in vivo conditions has been introduced. The method enables determination of the regional variation in mechanical behaviour across the ocular surface. Two numerical models based in continuum mechanics theory have been developed which represent the 3D anisotropic behaviour of the corneal stroma. Experimental data has been gathered from a number of previous studies to provide the basis and calibration parameters for the numerical modelling. The resulting models introduce numerical representation of collagen fibril density and its related regional variation, interlamellar cohesion and age-related stiffening in anisotropic and viscoelastic models of the human cornea. Further, the models incorporate previous modelling developments including representation of lamellae anisotropy and stiffness of the underlying matrix. Wide angle X-ray scattering has provided measured data which quantifies relative fibril anisotropy in the 2D domain. Accurate numerical description of material response to deformation is essential to providing representative simulations of corneal behaviour. Representing experimentally obtained 2D anisotropy and regional density variation in the 3D domain is an essential component of this accuracy. The constitutive model was incorporated into finite element analyses. Combining with inverse analysis, the model was calibrated to an extensive experimental database of ex vivo corneal inflation tests and ex vivo corneal shear tests. This model represented stiffness of the underlying matrix which is 2−3 orders of magnitude lower than the mechanical response representing the collagen fibrils in the lamellae. The presented model, along with its age dependent material coefficients, allows finite element modelling for an individual patient with material stiffness approximated based on their age. This has great potential to be used in both daily clinical practice for the planning and optimisation of corrective procedures and in pre-clinical optimisation of diagnostic procedures. The second constitutive numerical model based on the continuum mechanics theory was developed which extended the representation of the model above to include both age-related viscoelastic stiffening behaviour of the human cornea. Experimental data gathered from a number of previous studies on 48 ex vivo human cornea (inflation and shear tests) enabled numerical model calibration. The present study suggests that stiffness parallel to the lamellae of the cornea approximately doubles from an increase in strain-rate of 0.5 − 5%/min. While the underlying stromal matrix provides a stiffness 2−3 orders of magnitude lower than the lamellae. The model has been simultaneously calibrated to within 5% error across three age groups ranging from 50 − 95, multiple strain-rates and multiple loading scenarios. Age and strain-rate dependent material coefficients allow finite element modelling for an individual patient with material stiffness approximated by their age under varying loading scenarios. This present study addresses a significant gap in numerical representation of the cornea and has great potential in both daily clinical practice particularly in highly viscoelastic dependent simulations such as non-contact tomometry. Related to this thesis, the author has either primarily or secondarily authored the following related journal articles which are included in this thesis in modified forms: Whitford C. & Elsheikh A., Corneal Biomechanics Testing Methods, May 2014, Chinese Journal of Optometry and Ophthalmology Visual Science; Whitford C., Joda A., Jones S., Bao F., Rama P. & Elsheikh A., Ex-vivo Test- ing of Intact Eye Globes Under Inflation Conditions to Determine Regional Variation of Mechanical Stiffness, July 2016, Eye and Vision. Elsheikh, A., Whitford, C., Hamarashid, R., Kassem, W., Joda, A., B¨uchler, P., Stress free configuration of the human eye. Febuary 2013, Medical Engineering & Physics. Yu J., Bao F., Feng Y., Whitford C., Ye T., Huang Y., Wang Q., Elsheikh A., Assessment of Corneal Biomechanical Behavior Under Posterior and Ante- rior Pressure. January 2013, Journal of Refractive Surgery. Whitford C., Studer H., Boote K., Meek K.M. & Elsheikh A., Biomechanical Model of the Human Cornea: Considering Shear Stiffness and Regional Variation of Collagen Anisotropy and Density, Feb 2015, Journal of the Mechanical Behavior of Biomedical Materials. Elsheikh A., McMonnies C.W., Whitford C. & Boneham G.C., In-vivo study of Corneal Responses to Increased Intraocular Pressure, 2015, Eye and Vision. An additional journal publication has been prepared from the content in this present study: Whitford C., Movchan N. & Elsheikh A., A Viscoelastic Hyperelastic Anisotropic Model of the Human Cornea. Further, two book chapters have been published which related to this thesis: Whitford C., Studer H., Boote C., Meek K. & Elsheikh A., Modelo Biomecnico de la Crnea Humana Considerando la Variacin Regional de la Anisotropa, la Densidad y la Cohesin Interlaminar de las Fibrillas de Colgeno, in Biomec- nica y Arquitectura Corneal, May 2014. Geraghty B., Whitford C., Boote C., Akhtar R,. & Elsheikh A., Age-Related Variation in the Biomechanical and Structural Properties of the Corneo- Scleral Tunic, in Mechanical Properties of Ageing Soft Tissues, January 2015. In addition, a number of conference proceedings have been published.
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Siegel, Nathalie [Verfasser]. « Die isoliert perfundierte Rattenaorta : Etablierung eines ex vivo-Modells zur Untersuchung der medialen vaskulären Kalzifizierung / Nathalie Siegel ». Berlin : Freie Universität Berlin, 2016. http://d-nb.info/1113012439/34.
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SOPRANO, PAOLO MARIA. « Sviluppo di un modello di Midollo Osseo ex vivo per la produzione di piastrine e test farmacologici ». Doctoral thesis, Università degli studi di Pavia, 2022. http://hdl.handle.net/11571/1459968.
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SOPRANO, PAOLO MARIA. « Sviluppo di un modello di Midollo Osseo ex vivo per la produzione di piastrine e test farmacologici ». Doctoral thesis, Università degli studi di Pavia, 2022. http://hdl.handle.net/11571/1459967.
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SOPRANO, PAOLO MARIA. « Sviluppo di un modello di Midollo Osseo ex vivo per la produzione di piastrine e test farmacologici ». Doctoral thesis, Università degli studi di Pavia, 2022. http://hdl.handle.net/11571/1459965.
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Zielke, Freya [Verfasser]. « Experimenteller Vergleich von Elektrochemischer Lyse und Radiofrequenzablation in einem Ex-Vivo-Modell der porcinen Lunge / Freya Zielke ». Lübeck : Zentrale Hochschulbibliothek Lübeck, 2016. http://d-nb.info/110542863X/34.
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Zellmann, Svenja. « Der Effekt von Sirolimus auf die reaktive Zellproliferation und Apoptose in einem humanen ex vivo Restenose-Modell ». [S.l. : s.n.], 2007. http://nbn-resolving.de/urn:nbn:de:bsz:289-vts-60987.
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Holdorf, Karoline [Verfasser]. « Pathogenetische Bedeutung der Fcγ-Rezeptoren und Therapieoptionen des bullösen Pemphigoids : Untersuchungen an einem Ex-vivo-Modell / Karoline Holdorf ». Lübeck : Zentrale Hochschulbibliothek Lübeck, 2012. http://d-nb.info/1019057610/34.
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Strobel, Steffen Peter [Verfasser]. « Die ex-vivo-Perfusion hDAF-transgener Kaninchennieren mit Humanblut : ein Modell für die humane Xenotransplantation / Steffen Peter Strobel ». Ulm : Universität Ulm. Medizinische Fakultät, 2004. http://d-nb.info/1015471129/34.
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Trammer, Beatrice [Verfasser], et Petra [Akademischer Betreuer] Högger. « Ex-vivo-Modelle zur Charakterisierung der Pharmakokinetik pulmonal applizierter Wirkstoffe : Dialyse- und humanes Lungenperfusionsmodell / Beatrice Trammer. Betreuer : Petra Högger ». Würzburg : Universitätsbibliothek der Universität Würzburg, 2011. http://d-nb.info/1017232911/34.
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Hummel, Andreas [Verfasser], et Rejko [Akademischer Betreuer] Krüger. « Erforschung mitochondrialer Phänotypen in einem humanen ex vivo Modell mit A30P alpha-Synuklein Mutation / Andreas Hummel ; Betreuer : Rejko Krüger ». Tübingen : Universitätsbibliothek Tübingen, 2016. http://d-nb.info/1198120703/34.
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Vietze, Andrea [Verfasser]. « Ventilation verursacht einen Heat Sink Effect bei der Laserablation von Lungentumoren in einem humanen Ex-vivo-Modell / Andrea Vietze ». Greifswald : Universitätsbibliothek Greifswald, 2011. http://d-nb.info/1012031101/34.
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Vom, Hofe Burkhard [Verfasser], et Andreas [Akademischer Betreuer] Kirschbaum. « Doppelte bipolare Versiegelung von Lungenarterien : Bestimmung der Berstdrücke an einem ex-vivo-Modell / Burkhard Vom Hofe ; Betreuer : Andreas Kirschbaum ». Marburg : Philipps-Universität Marburg, 2020. http://d-nb.info/1210162563/34.
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Lippek, Frank. « Hemmung der Selektin-vermittelten Granulozytenadhäsion durch Fucoidin in der frühen Reperfusionsphase nach Ischämie im Modell der ex-vivo hämoperfundierten Schweineniere ». [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=962393894.
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Abicht, Jan-Michael [Verfasser]. « Untersuchungen zur perioperativen kardialen Xenograft-Dysfunktion im ex-vivo Modell sowie nach heterotop thorakaler und orthotoper Xenotransplantation / Jan-Michael Abicht ». München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2018. http://d-nb.info/1171131542/34.
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Riegger, Jana [Verfasser]. « Schadensbegrenzung und Regeneration nach Knorpeltrauma : Testung neuer Therapiekonzepte zur Prävention der posttraumatischen Arthrose im humanen ex vivo Modell / Jana Riegger ». Ulm : Universität Ulm, 2019. http://d-nb.info/1189734095/34.
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Lippek, Frank. « Hemmung der Selektin-vermittelten Granulozytenadhäsion durch Fucoidin in der frühen Reperfusionsphase nach Ischämie im Modell der ex-vivo hämoperfundierten Schweineniere ». Doctoral thesis, Humboldt-Universität zu Berlin, Medizinische Fakultät - Universitätsklinikum Charité, 2001. http://dx.doi.org/10.18452/14629.
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Der renale Ischämie-/Reperfusionsschaden (IRI) stellt in der Transplantationsmedizin ein grosses Problem dar. Fucoidin, ein potenter Antagonist der Selektin-vermittelten Leukozytenaggregation, verbesserte an der Rattenleber (in einer Konzentration von 360mg/l) das Ausmass der leukozytären Gewebeinfiltration in der frühen Phase nach Ischämie und Reperfusion. In einem Modell der isoliert hämoperfundierten Schweineniere sollte die Wirkung von Fucoidin auf die postischämische Organfunktion untersucht werden. Hierzu wurden 24 Versuche durchgeführt. Dem Blut der Versuchsgruppen wurde vor Beginn der Reperfusion Fucoidin in einer Konzentration von 100 mg/l zugesetzt. Es zeigte sich unter Fucoidin ein signifikanter Abfall des renalen Blutflusses (55 ( 28 vs. 143 ( 97 ml*min-1*100g-1, pRenal postischemic reperfusion injury constitutes a significant problem after kidney transplantation. The polysaccharide fucoidin (360 mg/l) improves postischemic function in Ratliver, presumably by blocking selectin-mediated leukocyte adhesion. Twelve pairs of ischemic pig kidneys were reperfused in an ex vivo model with autologous blood with or without fucoidin (100 mg/L). Fucoidin resulted in a significant decrease of renal blood flow (55 ( 28 vs. 143 ( 97 mL*min-1*100g-1, p < 0.001) and increased vascular resistance (2.9 ( 2.8 vs. 1.1 ( 1.5 mmHg*mL-1*min-1*100g-1, p < 0.001). Compared to untreated control kidneys significantly more interstitial and intravascular leucocytes were found in fucoidin treated kidneys. Intraglomerular fibrinogen and thrombocytic aggregates were also increased significantly. Granulocytic emboli were present in afferent glomerular arteries of 10/12 fucoidin-treated kidneys and in 2/12 controls (p < 0.001). L-selectin-dependent granulocytic aggregation under shear stress in vitro was prevented by fucoidin in a dose-dependent fashion. However similar concentrations used in reperfused kidneys caused large granulocytic aggregates. The observed formation of embolizing granulocytic aggregates indicates limited effectiveness of fucoidin as an inhibitor of selectin-mediated leukocyte adhesion.
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Spennes, Judith [Verfasser]. « Periprothetische Zementverteilung bei femoralen Oberflächenersatzprothesen im Vergleich : Kunstknochen versus humaner Ex-vivo-Knochen ; Etablierung eines standardisierten In-vitro-Modells / Judith Spennes ». Aachen : Hochschulbibliothek der Rheinisch-Westfälischen Technischen Hochschule Aachen, 2011. http://d-nb.info/1016493398/34.
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Baumann, Daniel [Verfasser], et Petra [Akademischer Betreuer] Högger. « Charakterisierung der Pharmakokinetik und Pharmakodynamik intranasaler Glucocorticoide anhand von in vitro und ex vivo Modellen / Daniel Baumann. Betreuer : Petra Högger ». Würzburg : Universitätsbibliothek der Universität Würzburg, 2011. http://d-nb.info/101361979X/34.
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Rüdell, Franziska [Verfasser], et Andreas [Akademischer Betreuer] Kirschbaum. « Einfluss der Kompression auf dei Berstdrücke nach bipolarer Gefäßversiegelung - Untersuchung an einem ex vivo Modell der Pulmonalarterie / Franziska Rüdell ; Betreuer : Andreas Kirschbaum ». Marburg : Philipps-Universität Marburg, 2018. http://d-nb.info/1174304707/34.
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Manthey, Constanze [Verfasser]. « Experimentelle Untersuchung der elektrochemischen Lyse an einem Ex-vivo-Modell einer perfundierten porzinen Lunge zur Erstellung einer Dosis-Wirkungs-Beziehung / Constanze Manthey ». Lübeck : Zentrale Hochschulbibliothek Lübeck, 2017. http://d-nb.info/1147720347/34.
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Sannwaldt, Benedict-Douglas [Verfasser]. « Vergleich von Radiofrequenzablation und Elektrochemischer Lyse am Ex-vivo-Modell der isolierten und porcinen Leber unter Simulation des Pringle-Maneuvers / Benedict-Douglas Sannwaldt ». Lübeck : Zentrale Hochschulbibliothek Lübeck, 2015. http://d-nb.info/1073140032/34.
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Silva, Natalia Aparecida Nepomuceno da. « Avaliação ex vivo de pulmões de ratos submetidos ao choque hemorrágico : reposição volêmica com Solução Hipertônica x Solução Salina ». Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/5/5156/tde-24022016-082523/.
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[Tese]. São Paulo: Faculdade de Medicina, Universidade de São Paulo; 2015. A escassez dos doadores e a má qualidade dos órgãos associados à falta de cuidado em sua manutenção são um grave problema para os grupos de transplante, especialmente para o transplante pulmonar. Um dos principais motivos de recusa para a doação é o edema pulmonar, que pode estar associado a excessiva administração de fluídos no tratamento do choque hemorrágico. Dentre as causa de choque, o choque hemorrágico está frequentemente associado aos doadores vítimas de traumatismo. Uma das estratégias clínicas aplicadas para a recuperação do choque hemorrágico é a administração precoce de fluídos e produtos sanguíneos. O uso de soluções cristalóides como Soluções Isotônicas e Hipertônicas promove a expansão volêmica intravascular restabelecendo a pressão arterial média. A ressuscitação volêmica com cristalóide isotônico requer administração de alta quantidade de volume, em contrapartida a solução hipertônica a 7,5% mostra uma redução de três a quatro vezes no volume. Na tentativa de aumentar a oferta de doadores de pulmão nossa hipótese baseia-se na realização de um tratamento com solução Salina Hipertônica em doadores com choque hemorrágico. O objetivo deste trabalho é avaliar pulmões de ratos submetidos ao choque hemorrágico tratados com solução hipertônica comparando com a solução salina. Oitenta ratos foram divididos em 4 grupos: Sham (Sham n=20); Choque (Choque n=20); SS ( Choque + Solução Salina n=20) e SH ( Choque + Solução Hipertônica n=20). Após anestesia, os animais foram submetidos à cateterização da artéria e veia femoral para registro de pressão arterial média (PAM) e obtenção do choque hemorrágico. No grupo Sham foi realizada a monitorização dos parâmetros, nos grupos Choque, SS e SH obtenção do choque hemorrágico (40 mmHg), e tratamento de solução hipertônica (4 ml/Kg) no grupo SH e solução salina (33 ml/kg) no grupo SS. Após 120 minutos, 10 blocos cardiopulmonares de cada grupo foram encaminhados ao sistema de perfusão ex vivo Harvard Apparatus IL-2 Isolated Perfused e avaliados durante 60 minutos, os outros 10 blocos dos grupo foram destinados a dosagem de citocinaTnf-alfa, IL 1-beta e quantificação de neutrófilo. Na avaliação ex vivo o parâmetro que apresentou diferença estatística significante foi a Pressão da artéria Pulmonar (PAP) do grupo Choque em relação aos demais grupos (p < 0,05). A dosagem de Tnf-alfa no grupo choque foi superior a todos os grupo (p < 0,05). Em relação a contagem de neutrófilos o grupo tratado com solução hipertônica e solução isotônica apresentaram resultado igual ao grupo Sham,o grupo choque apresentou infiltrado neutrofílico superior aos demais grupos (p < 0,05). Concluímos que os pulmões de ratos submetidos ao choque hemorrágico tratados com solução hipertônica apresentam parâmetros de mecânica ventilatória semelhante e recuperação hemodinâmica melhor do que os animais tratados com solução salina a 0,9%. Além disso, reduz os parâmetros inflamatórios dos animais submetidos ao choque hemorrágicoThe lack of donors and poor quality of organs associated to poor organ handling is a serious problem for transplantation groups, especially for lung transplantation. Pulmonary edema is one of the main reasons for donation rejection, which may be associated to excessive fluid administration in the treatment of hemorrhagic shock. Of the causes of shock, hemorrhagic shock is frequently associated to donors who are victims of trauma. One of the clinical strategies used in the recovery of hemorrhagic shock is the early administration of fluids and blood products. The use of crystalloid solutions such as Isotonic and Hypertonic Solutions promote intravascular volume expansion thus reestablishing mean blood pressure. Volume resuscitation with isotonic crystalloid requires the administration of a high amount of volume, whereas hypertonic solution 7.5% produces a three or four fold volume reduction. In an attempt to increase the offer of lung donors, our hypothesis is based on a treatment with hypertonic saline solution in donors with hemorrhagic shock. The objective of this study is to evaluate the lungs of rats undergoing hemorrhagic shock treated with hypertonic solution compared to saline solution. Eighty rats were divided into 4 groups: Sham (Sham, n=20); Shock (Shock, n=20); SS (Shock + Saline Solution, n=20) and SH ( Shock + Hypertonic Solution, n=20). After anesthesia, animals were submitted to catheterization of the femoral artery and vein to record mean arterial pressure (MAP) andto obtain hemorrhagic shock. In the Sham group the different parameters were monitored, in the Shock, SS and SH groups hemorrhagic shock was obtained (40 mmHg). The SH group received the hypertonic solution (4 ml/Kg) and the SS group received saline solution (33 ml/kg). After 120 minutes, 10 cardiopulmonary blocks of each group were evaluated by the ex vivo Harvard Apparatus IL-2 Isolated Perfused system for 60 minutes, the other 10 blocks were had cytokine TNF-alpha and IL 1-beta measurement and neutrophil quantification performed. In the ex vivo evaluation, pulmonary artery pressure (PAP) was the variable with statistically significant difference (p < 0.05) in the shock group when compared to the other groups. TNF-alfa measurement in the shock group was higher than in all of the other groups (p < 0.05). Neutrophil counts in the groups treated with hypertonic solution and isotonic solution were similar to the Sham group. The shock group had higher neutrophil infiltrate values than the other groups (p < 0.05). We conclude that the lungs of rats undergoing hemorrhagic shock treated with hypertonic solution had similar mechanical ventilation parameters and better hemodynamic recovery than the animals treated with 0.9% saline solution. Furthermore, it reduced the inflammatory parameters of animals undergoing hemorrhagic shock
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Birkfeld, Daniel [Verfasser]. « Einfluss eines Phosphodiesterase-2-Inhibitors auf die Hämodynamik und die endothel-alveoläre Barriere nach in-vivo-Priming mit LPS und ex-vivo-Applikation von Pneumolysin am Modell der isolierten Rattenlunge / Daniel Birkfeld ». Gießen : Universitätsbibliothek, 2015. http://d-nb.info/1068874805/34.
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Trocme, Caryn. « Role des sequences cre et tre dans la regulation de l'expression du gene codant pour la tyrosine hydroxylase de rat ; etudes ex vivo et par transgenese ». Paris 11, 1997. http://www.theses.fr/1997PA11T026.
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Morris, Gwilym. « Characterisation of subsidiary pacemaker tissue in an ex vivo model of sick sinus syndrome and its utility for biopacemaking ». Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/characterisation-of-subsidiary-pacemaker-tissue-in-an-ex-vivo-model-of-sick-sinus-syndrome-and-its-utility-for-biopacemaking(912a000a-47f1-4302-b6c8-894161d6a04b).html.
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Background: Sick sinus syndrome (SSS) is common and may require electronic pacemaker implantation, gene therapy (biopacemaking) may be an alternative. For SSS, repair may be better than the generation of a de novo biopacemaker, due to the complex nature of the sinoatrial node (SAN). We hypothesised that an ex vivo model of SSS could be created by the identification of a subsidiary pacemaker in the SAN region, and that expression of a pacemaker channel (HCN4 or HCN212) in this region would accelerate the pacing rate. Methods: A bradycardic SSS model was generated by the removal of the upper two thirds of a rat SAN and a system to record the intrinsic activity during tissue culture was developed. The leading pacemaker site of the SSS preparations were identified by activation mapping then characterised by If blockade, β-adrenergic stimulation, histology and immunohistochemistry. Further SSS preparations were injected in this region with recombinant adenovirus (RAd) expressing no functional ion channel (Ad5-GFP or Ad5-GFP-HCN4Δ); or RAd expressing a functional If channel (Ad5-HCN212 or Ad5-PREK-HCN4). During tissue culture electrical activity was monitored using bipolar electrodes. Results: Tissue culture and monitoring of the rat SAN is feasible and does not induce significant changes in HCN4 or connexin-43 expression. The uninjected SSS preparations displayed a slower rate than the control SAN (p<0.001). In 5/6 cases the subsidiary pacemaker was HCN4 -ve and Connexin-43 +ve (in contrast to the SAN) and was close to the superior aspect of the inferior vena cava. The cell size of the subsidiary pacemaker was comparable to that of the SAN and smaller than working myocardium (p<0.001). Pacing was responsive to β-adrenergic stimulation and was partially dependent on If current. The pacing rate of the AdHCN212-injected SSS preparations was significantly faster than the uninjected SSS preparations (p<0.001). The remaining RAd did not significantly affect the pacing rate of the SSS model. Conclusions: There is subsidiary pacemaker tissue close to the superior aspect of the IVC that shares some characteristics of the SAN. These results suggest that adenovirus-mediated expression of HCN channels in subsidiary pacemaker tissue of the right atrium may be a useful strategy in biopacemaking for SSS.
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Menaouar, Ahmed. « Mécanismes de l'oedème pulmonaire provoqué par le chlore : effets de l'inhalation de monoxyde d'azote ». Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE10190.
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L'inhalation de chlore (cl2) provoque des lesions tracheo-bronchiques et un deme pulmonaire de type inflammatoire. Nous avons etabli des modeles experimentaux ex vivo et in vivo pour etudier les mecanismes de cet deme ainsi que l'efficacite therapeutique de l'inhalation de monoxyde d'azote (no). Sur le poumon isole de lapin, nous avons provoque un deme pulmonaire par inhalation de 500 ppm de cl2 pendant 10 minutes. La pression de filtration, la clairance de l'albumine (calb) et le coefficient de filtration (kf = conductivite a l'eau x surface de filtration) ont ete mesures avant et 30 minutes apres administration de cl2. L'inhalation de cl2 a augmente de 200% le kf et la calb, de 100% l'eau extravasculaire (eev), sans modifications de la pression et de la surface de filtration. Ces resultats suggerent que l'deme alveolaire induit par le cl2 est du essentiellement a une augmentation de la permeabilite capillaire et que sa formation est facilitee par la lesion de l'epithelium alveolaire. L'inhalation de 40 ppm de no, 5 minutes apres l'inhalation de cl2, a diminue de 30% l'alteration du kf, de calb et de eev. Le mecanisme d'action du no n'est pas une diminution de la pression de filtration. Il s'agit davantage d'une diminution de l'alteration de la permeabilite capillaire que d'une diminution de la surface de filtration des zones lesees. Chez le chien anesthesie, l'exposition a 250 ppm de cl2 pendant 10 minutes a entraine une augmentation du debit lymphatique pulmonaire par un facteur 2,8, de la clairance des proteines par un facteur 2,5, et de eev par un facteur 1,5. Ce modele in vivo, ou la microcirculation bronchique est fonctionnelle, a montre des differences avec le modele ex vivo, notamment l'importance du spasme bronchique et de l'hypoventilation alveolaire. Le mecanisme de l'deme pulmonaire dans ce modele etait une augmentation a la fois de la permeabilite capillaire et de la pression de filtration
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Kaba, Shajadi Carlos Pardo. « Análise clínica do trauma operatório aos tecidos da articulação temporomandibular entre artroscopia e artrocentese. Estudo em suínos ex vivo ». Universidade de São Paulo, 2016. http://www.teses.usp.br/teses/disponiveis/23/23139/tde-04112016-105710/.
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A artroscopia e a artrocentese são procedimentos considerados minimamente invasivos utilizados para o tratamento das disfunções temporomandibulares (DTM) e são métodos considerados intermediários entre a terapia conservadora e a cirurgia aberta da articulação temporomandibular (ATM). Apresentam como vantagem, em relação a cirurgia aberta, a pequena morbidade e o breve tempo de recuperação necessária aos pacientes. Desde o início do desenvolvimento da artroscopia esteve presente a preocupação com a possibilidade de danos a estruturas internas da ATM, com essa finalidade vários estudos em animais foram desenvolvidos evidenciando que realmente podem ocorrer lesões iatrogênicas as estruturas internas desencadeando processo degenerativo na articulação. A avaliação do mesmo potencial de lesão para artrocentese não existe, assim o objetivo deste trabalho foi avaliar o trauma operatório da artrocentese comparativamente a artroscopia aos tecidos da ATM em suínos. Realizou-se experimento em vinte ATM de dez cabeças de suínos sendo seis artroscopias; seis artrocenteses e oito ATM utilizadas como controle. Após a realização dos procedimentos as ATM foram cuidadosamente dissecadas, examinadas e fotografadas com registro de alterações traumáticas ao disco articular e as fibrocartilagens da fossa articular e da cabeça da mandíbula. As imagens das estruturas foram analisadas por outro examinador que não tinha conhecimento prévio de qual procedimento havia sido realizado em cada ATM classificando as lesões de acordo com o número e localidade em: ausente (sem alteração visível); leve (descolamento de fibrocartilagem da fossa ou cabeça da mandíbula isoladas e únicas), moderado (perfurações do disco e mais de um descolamento de fibrocartilagem da fossa ou cabeça da mandíbula) e severo (lacerações do disco e lesões múltiplas em mais de uma estrutura). Os dados também foram classificados em ausente e presente para uma comparação direta. Foi realizada análise estatística dos dados. No grupo controle ocorreram danos em duas das oito ATM durante a dissecção, que apresentaram características distintas das lesões constatadas após os procedimentos, nas outras seis nenhuma alteração traumática pode ser evidenciada. No grupo submetido a artrocentese os danos foram ausentes, leves e moderados em 16.7% respectivamente e severos em 50% da amostra. No grupo submetido a artroscopia ocorreram danos moderados em 66.7%, severos em 16.7%, ausentes em 16.7% e não ocorreram danos leves. Em ambos os grupos foram evidenciadas a presença de lesões em 83.3% das amostras. Apesar de não haver diferença estatisticamente significativa entre os danos verificados, em uma análise direta, a severidade das lesões constatadas após artrocentese foi maior. Conclui-se que a artrocentese e a artroscopia não são isentas de morbidade aos tecidos articulares e independentemente de serem procedimentos considerados minimamente invasivos não se pode desprezar o potencial de danos as superfícies articulares.Arthroscopy and arthrocentesis are considered minimally invasive procedures for the treatment of temporomandibular disorders (TMD) and are situated between conservative therapies and open surgery of the temporomandibular joint (TMJ). When compared to open surgery they present the advantages of having a brief post operatory recovery time for the patient and little morbidity. Since the beginning of the development of arthroscopy the possibility of damage to the inner structures of the TMJ was a concern, as a result a series of studies in animals were made and it became clear that iatrogenic damage can really happen and trigger degenerative alterations in the joint. Considering that there are no studies that investigate the potential of causing structural damage to the TMJ during arthrocentesis the objective of this study was to evaluate the operative trauma of arthroscopy and arthrocentesis to the tissues of the TMJ using swine heads. Twenty TMJ of ten swine heads were used for six arthroscopies; six arthrocentesis and eight that were used as a control group. After the procedures the TMJ were carefully dissected, examined and photographed. Traumatic alterations to the articular disk and to the fossa and head of the mandible fibrocartilage were recorded. The images of the structures were analyzed by other examiner that did not had previous knowledge of witch procedure each TMJ was subjected to. The lesions that were identified were classified according to the location and number as: absent (no visible alteration); light (one isolated scuffing of the fibrocartilage of the fossa or the head of the mandible); moderate (disk perforation or multiple scuffing of the fibrocartilage of the fossa or head of the mandible) and severe (disk laceration or multiple lesions in more than one structure). The obtained data was also classified as absent or present for a direct comparison. Statistical analyses of the obtained data were made. In the control group damage to two of the eight TMJ was perceived during dissection, the characteristics of those lesions were clearly different from those observed after the procedures, in the other six none traumatic damage could be noticed. In the arthrocentesis group the damages were absent, light and moderate in 16.7% respectively and were severe in 50% of the sample. In the arthroscopy group damage was moderate in 66.7%, severe in 16.7%, absent in 16.7 and no light damage occurred. In both groups damage was present in 83.3% of the sample. Even though the difference between the groups was not statistically significant, making a direct analysis of the data, the severity of the lesions found in the arthrocentesis group was higher. It was concluded that arthrocentesis and arthroscopy are not absent of morbidity to the TMJ tissues and regarded of being minimally invasive procedures the potential of damage to the structures of the TMJ should not be minimized.
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Gozalbes-Bappel, Catherine. « Effets vasculaires de deux diurétiques de l'anse : pirétanide et furosémide. Etudes ex vivo chez le rat spontanément hypertendu et in vitro chez le cobaye ». Bordeaux 2, 1997. http://www.theses.fr/1997BOR28532.
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Kreft, Gerald. « Erprobung neuer Lasersonden für die laserinduzierte Thermotherapie unter MRT-Kontrolle Korrelation der histologisch gesicherten Nekrose mit der MR-Bildgebung ; Untersuchungen an einem ex-vivo Schweineleber-Modell / ». [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968783384.
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Kinter, Bernd. « Untersuchung zum Einfluss der ischämischen Präkonditionierung auf die Freisetzung von Noradrenalin und die ventrikuläre Flimmerrate am Rattenherz ex vivo (Langendorff-Modell) unter Berücksichtigung des transmembranären Protonengradienten ». Diss., lmu, 2003. http://nbn-resolving.de/urn:nbn:de:bvb:19-17806.
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Manders, Alice [Verfasser], Walter [Akademischer Betreuer] Brehm, Walter [Gutachter] Brehm et Griensven Martijn [Gutachter] van. « Entwicklung eines Sehnendefekt-Modells beim Schaf zur Simulation von Core Lesions - Literaturreview und Methodenentwicklung ex-vivo / Alice Manders ; Gutachter : Walter Brehm, Martijn van Griensven ; Betreuer : Walter Brehm ». Leipzig : Universitätsbibliothek Leipzig, 2013. http://d-nb.info/1238367267/34.
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Haas, Martin [Verfasser], et Petra [Gutachter] Högger. « Charakterisierung pharmakokinetischer und pharmakodynamischer Aspekte der Anwendung von Glucocorticoiden in der Herzschrittmachertherapie anhand von ex-vivo und in-vitro Modellen / Martin Haas. Gutachter : Petra Högger ». Würzburg : Universität Würzburg, 2016. http://d-nb.info/1111784647/34.
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Kappel, Dominique Josua [Verfasser], et Bernhard [Akademischer Betreuer] Krämer. « Experimentelle Untersuchung der thermischen Eigenschaften eines Hochfrequenz-Applikator-Prototyps an einem porcinen Ex-vivo-Mamma-Modell unter Verwendung der Infrarot-Messtechnik / Dominique Josua Kappel ; Betreuer : Bernhard Krämer ». Tübingen : Universitätsbibliothek Tübingen, 2020. http://d-nb.info/1203622775/34.
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Simon, Carole [Verfasser]. « Fluoreszenzspektroskopische Untersuchungen und Bestimmung optischer Parameter an in vitro und ex vivo Modellen für die Photodynamische Inaktivierung von Helicobacter pylori mit Chlorin e6 : Dissertation / Carole Simon ». Aachen : Shaker, 2015. http://d-nb.info/108076223X/34.
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Azevedo, Juliana Chris Silva de. « Caracter?sticas bioativas, funcionais e efeito protetor do res?duo desidratado de camu-camu (Myrciaria dubia H.B.K. (McVaugh)) sobre doen?as degenerativas utilizando modelos in vivo C. elegans ». Universidade Federal do Rio Grande do Norte, 2015. http://repositorio.ufrn.br/handle/123456789/20096.
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Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES
Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico - CNPq
O camu-camu (Myrciaria dubia H.B.K. (McVaugh)) ? um fruto nativo da Regi?o Amaz?nica, que se tornou mundialmente conhecido por seu alto teor de ?cido asc?rbico. Devido a seu elevado grau de acidez, o fruto ? consumido principalmente como suco ou utilizado como ingrediente na prepara??o de alimentos. Dessa maneira, durante seu processamento s?o geradas quantidades consider?veis de res?duo agroindustrial. Apesar de estudos que apontam sua riqueza em compostos bioativos e efeitos biol?gicos, poucas s?o as informa??es sobre t?cnicas de transforma??o, aproveitamento e preserva??o dos frutos e de seu res?duo industrial, as quais poderiam ser empregadas em prol de sua utiliza??o funcional. Sendo assim, o presente trabalho teve como objetivo avaliar a aplica??o de dois processos de secagem, por convec??o em secador de bandejas e por liofiliza??o sobre o res?duo de camu-camu (constitu?do por casca e sementes com polpa aderida), visando obter um produto com qualidades funcionais. A presente tese foi dividida em tr?s etapas: a primeira etapa mostra os estudos relacionados ? secagem convectiva e liofiliza??o, na qual foi avaliado o impacto de ambos os processos sobre compostos bioativos selecionados, tomando o res?duo fresco como amostra controle. Dentre as condi??es estudadas, os grupos obtidos por convec??o a 50?C e 4 m/ s (SC50) e 80?C e 6 m/ s (SC80) apresentaram melhor combina??o de concentra??o de ?cido asc?rbico, capacidade redutora do Folin-Ciocalteau e caroten?ides totais, e foram selecionados para estudos complementares. Al?m disso, o res?duo liofilizado (RL) e o res?duo fresco (RF) foram investigados nas etapas posteriores da pesquisa. De maneira geral, foi observada maior concentra??o dos constituintes bioativos no grupo RF, seguido do RL e, por fim, os res?duos desidratados por convec??o, SC50 e SC80, respectivamente. Na segunda etapa, foram avaliadas atividades antioxidante, microbiol?gica e antienzim?tica, onde tamb?m foi observada a mesma tend?ncia nos resultados. Nessa etapa, foi identificada, pela primeira vez na literatura, a presen?a do ?cido sir?ngico no res?duo do camu-camu. A terceira parte desta tese abordou a investiga??o dos efeitos do res?duo de camu-camu desidratado sobre o envelhecimento e doen?as neurodegenerativas, utilizando o modelo in vivo C. elegans. Os extratos de camu-camu foram capazes de favorecer genes importantes das vias de ativa??o/inibi??o do estresse oxidativo e t?rmico (p < 0,05). Para o verme do tipo selvagem N2, as fra??es do extrato de baixo peso molecular PA (fase aquosa e polar ?cida), PB (fase aquosa e polar b?sica) e PN (fase org?nica e polar neutra) do grupo SC50 estenderam o tempo de vida em 20% e 13% (p < 0,001). Os resultados obtidos revelaram que a paralisia induzida pelo pept?deo Amil?ide ?1-42 associada a doen?a de Alzheimer, foi retardada significativamente (p < 0,0001) na linhagem CL4176. Da mesma forma, os extratos de camu-camu foram capazes de atenuar a indu??o dopamin?rgica associada ao mal de Parkinson. Finalmente, a an?lise global dos dados mostra que o res?duo de camucamu, co-produto obtido a partir de uma fruta nativa Brasileira, constitui uma fonte natural de compostos relevantes para a sa?de humana. Dessa forma, a presente tese mostra de maneira in?dita a multifuncionalidade desse produto ainda subaproveitado do ponto de vista cient?fico, comercial e tecnol?gico.
Camu-camu (Myrciaria dubia H.B.K. (McVaugh)) is a native Amazon fruit, recognized worldwide as one of the main natural sources of ascorbic acid. Due to its great acidity, this fruit is generally consumed after processing into juice or as ingredient in food preparations. As a co-product of the camu-camu processing, a significant amount of agroindustrial residue is generated. Despite the studies showing the bioactive value and biological potential of the fruit, few studies have approached the possible processing techniques, transformation and preservation of camu-camu fruits and its agroindustrial pomace. Therefore, the present work has the objective of evaluating two different drying processes applied to camu-camu pomace (peel and seeds with residual pulp), freeze drying and hot air drying, in order to obtain a functional fruit product. This thesis was divided into three stages: the first one shows the studies related to the freeze drying and hot air drying, where we demonstrated the impact of the selected drying techniques on the bioactive components of camu-camu, taking the fresh pomace as the control group. Among the investigated conditions, the groups obtained at 50?C and 4 m/s (SC50) and 80?C and 6 m/s (SC80) were selected as for further studies, based on their ascorbic acid final content and Folin-Ciocalteau reducing capacity. In addition to SC50 and SC80, the fresh pomace (RF) and freeze dried (RL) samples were also evaluated in these further stages of the research. Overall, the results show higher bioactive concentration in the RF samples, followed by RL, SC50 and SC80. On the second step of the research, the antioxidant, antimicrobial and antienzymatic activities were evaluated and the same tendency was observed. It was also reported, for the first time in the literature, the presence of syringic acid in dried camu-camu pomace. In the third and final stage of the research, it was investigated the effect of dried camu-camu on aging and neuroprotective disorders, using the in vivo model C.elegans. It was observed that camu-camu extracts were able to modulate important signaling genes relevant to thermal and oxidative stresses (p < 0.05). The polar acid, polar basic and polar neutral fractions obtained from the low molecular extracts of SC50 were able to extend the lifespan of wild type N2 C. elegans in 20% and 13% (p < 0.001). Results also showed that the paralysis induced by the ?1-42 amyloid was significantly (p < 0.0001) retarded in CL4176 worms. Similarly, the camu-camu extracts attenuated the dopaminergic induction associated to Parkinson?s disease. Finally, a global analysis of the data presented here reveal that the camu-camu pomace, a co-product obtained from the industrial processing of a native Brazilian fruit, is a relevant natural source of health relevant compounds. This thesis, shows for the first time, the multifunctionality of camu-camu pomace, a natural resource still underexploited for scientific, commercial and technological purposes.
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Menezes, Arteiro Queiroz. « Estudo de pulmões de ratos reperfundidos em um modelo experimental ex-vivo : comparação entre duas soluções de preservação (Perfadex® e Celsior®) ». Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/5/5156/tde-09082013-120744/.
Texte intégralRésumé :
INTRODUÇÃO: A lesão de isquemia-reperfusão continua sendo considerada a maior causa de mortalidade relacionada ao transplante de pulmão e sua gravidade é influenciada por diversos fatores, dentre eles, a preservação pulmonar. OBJETIVO: Comparar duas soluções de preservação pulmonar, Perfadex® e Celsior®, quanto a capacidade de preservação de tecido pulmonar isquêmico. MÉTODOS: Sessenta pulmões de ratos preservados com Perfadex®, Celsior® ou solução salina após períodos de isquemia hipotérmica de 6 ou 12 horas, foram reperfundidos com sangue homólogo em modelo experimental ex-vivo durante 60 minutos consecutivos. A cada 10 minutos os dados de gasometria, hematócrito, mecânica ventilatória, hemodinâmica e peso do bloco cardiopulmonar foram registrados. Ao final da reperfusão o pulmão esquerdo foi pesado e acondicionado por 48h a 70oC para obtenção da razão peso úmido/peso seco, bem como amostras de tecido pulmonar foram retiradas para histopatologia, microscopia eletrônica e TUNEL. A análise estatística incluiu a comparação entre as soluções e os tempos de isquemia, utilizando ANOVA e Kruskall-Wallis. O nível de significância foi de 5%. RESULTADOS: A comparação entre as complacências de pulmões preservados com Celsior® e Perfadex® nos tempos de isquemia de 6 e 12 horas não apresentou significância estatística (p=0,161 e p=0,316, respectivamente). Os pulmões submetidos a 6 horas de isquemia apresentaram complacência pulmonar superior aos de 12 horas (Perfadex® p=0,02; Celsior® p=0,019; Salina p=0,016). Os valores de pressão arterial pulmonar foram semelhantes entre as três soluções nos dois tempos de isquemia, bem como na comparação entre os tempos de 6 e 12 horas, independente da solução. A Capacidade Relativa de Oxigenação não demonstrou diferença estatística entre as três soluções, independentemente do tempo de isquemia. Na comparação entre os dois tempos de isquemia, o desempenho da oxigenação foi significativamente pior nos pulmões preservados com salina por 12 horas (p=0,001). A razão peso úmido/peso seco não apresentou diferença estatística significante entre as três soluções nos dois tempos de isquemia, porém na comparação entre os tempos de isquemia, os pulmões preservados com Perfadex® apresentaram uma relação peso úmido/peso seco maior no tempo de isquemia mais longo (p=0,001). À microscopia óptica, pulmões preservados com salina apresentaram mais edema que os demais, independentemente do tempo de isquemia. A avaliação da apoptose celular através do método de TUNEL não mostrou diferença estatisticamente significativa na comparação entre os grupos. CONCLUSÃO: Os pulmões preservados com Perfadex® e Celsior® apresentaram desempenho similar em relação às trocas gasosas e parâmetros hemodinâmicos e de mecânica ventilatória. Os pulmões preservados com Perfadex® por 12 horas apresentaram mais edema. Os achados histopatológicos não diferiram entre os grupos estudadosINTRODUCTION: Ischemia-reperfusion injury remaisn the leading cause of mortality related to lung transplantation. Its severity is influenced by several factors including lung preservation. OBJECTIVE: To compare two lung preservation solutions, Perfadex® and Celsior® and its ability to preserve ischemic lung tissue. METHODS: Sixty rat lungs were preserved with Perfadex®, Celsior® or saline after a cold ischemic period of 6 or 12 hours and were then reperfused with homologous blood in an ex vivo experimental model for 60 consecutive minutes. At 10-minute intervals during reperfusion of the heart-lung blocks, data were collected for blood gases, hematocrit, mechanical ventilation, hemodynamic and the heart-lung block weight was recorded. At the end of reperfusion, the left lung was weighed and packaged kept at 70oC for 48h to obtain the wet-to-dry weight ratio. Lung tissue samples were processed for histology, electron microscopy and TUNEL. Statistical analysis included a comparison of the solutions and ischemic times, using ANOVA and Kruskal-Wallis. The significance level was set at 5%. RESULTS: The comparison between the compliance of lungs preserved with Celsior® and Perfadex® in ischemic times of 6 and 12 hours was not statistically significant (p=0.161 and p=0.316, respectively). The lungs subjected to 6 hours of ischemia showed higher lung compliance compared to 12 hours (p=0.02 Perfadex®; Celsior® p=0.019; saline p=0.016). The pulmonary artery pressure values were similar between the three solutions in two stages of ischemia and comparing the times of 6 and 12 hours, regardless of the solution. The Relative Oxygenation Capacity showed no significant difference between the three solutions tested, regardless of the ischemic time. The comparison between the two ischemic times showed that oxygenation capacity was significantly worse in lungs preserved with saline for 12 hours (p=0.001). The wet-to-dry weight ratio showed no statistically significant difference between the three solutions in both ischemic times. However, when ischemic times were compared, Perfadex® showed greater wet-to-dry weight ratio in lungs submitted to 12 hours of ischemia (p=0.001). Light microscopy showed that lungs preserved with saline had more edema than the others, regardless of the ischemic time. Assessment of apoptosis by the TUNEL assay showed no statistically significant difference in the comparison between the groups. CONCLUSIONS: The lungs preserved with Celsior® and Perfadex® performed evenly in regards to gas exchange, hemodynamics and ventilatory mechanics. The lungs preserved with Perfadex® for 12 hours were more edematous. Histopathology findings did not differ between the groups