1,720,970 research outputs found
In vivo anti-inflammatory and anti-platelet aggregation activities of longissiminone A, isolated from Usnea longissima
No full textSecondary metabolite, longissiminone A (1) was isolated from a lichen, Usnea longissima. It was screened for its' in vivo anti-inflammatroy and anti-platelet aggregation activities. Compound 1 showed moderate in vivo anti-inflammatory activity as well as moderately active against the aggregation induced by arachidonic acid at different doses
Different regulation of aryl hydrocarbon receptor-regulated genes in response to dioxin in undifferentiated and neuronally differentiated human neuroblastoma SH-SY5Y cells
No full textSome environmental pollutants derived from industrial processes have been suggested to be responsible for neurological impairment in children, especially in heavily polluted areas. Since these compounds are usually activators of aryl hydrocarbon receptor (AhR), it would be important to better understand the molecular pathways downstream of AhR leading to neural deficits. To this purpose, appropriate in vitro human neural model is much needed. Here we have investigated whether undifferentiated and neuronally differentiated human neuroblastoma cells, SH-SY5Y cells, can provide a suitable model for monitoring AhR activity induced by environmental pollutants, focusing on 2,3,7,8-tetrachlordibenzo-p-dioxin (TCDD), a known activator of AhR. Further characterization of differentiated SH-SY5Y showed an increase in AhRR (aryl hydrocarbon receptor repressor), no change in ARNT1 (AhR nuclear translocator 1), and a decrease in ARNT2 expression with differentiation; in contrast, AhR was undetectable in both undifferentiated and differentiated cells. Nonetheless, treatment of parental as well as differentiated SH-SY5Y cells with TCDD resulted in the induction of AhR-regulated genes, CYP1A1 and CYP1B1; AhRR expression was also affected, but to a much smaller extent. These results indicate that undifferentiated SH-SY5Y are less sensitive to TCDD than neuronally differentiated ones, suggesting a higher resistance of the undifferentiated tumor cells to toxic insults. They also suggest that TCDD in these cells may not act via direct activation of AhR that is undetectable in SH-SY5Y as well as in differentiated neurons. Hence, these cells do not provide an appropriate model for studying ligand-mediated activation of AhR
TIPS-Pentacene as Biocompatible Material for Solution Processed High-Performance Electronics Operating in Water
No full textElectrophysiological analysis of human cells derived from neuronal differentiation of skin mesenchymal stem cells
Full text linkHuman skin hair follicle are a niche for different kind of adult mesenchymal stem cells (MSCs) such as neural crest stem cells and skin-derived precursor cells. MSCs ability to differentiate in neural and glial-like cells is of great interest for regenerative medicine as well as for the comprehension of molecular mechanisms involved in the development and the cure of neuropathies. Even if with reduced differentiative potential, MSCs have undoubtable economic advantages with respect to reprogrammed stem cells (iPSCs); at the same time, they already have well established therapeutic potential in animal models of stroke, spinal cord injury and multiple sclerosis. Starting from Prof. Bortolozzi’s lab protocol for the extraction, proliferation, and differentiation of adult MSCs into neurons, we performed electrophysiology experiments to characterize three different monoclonal populations selected from seven by mRNA analysis before the differentiation step.The patch- clamp technique has been used to depolarize single cells at different neuronal maturation stages to monitor resting potential and voltage-dependent electrical activity. To validate our patch clamp protocol, we used primary cultures of mouse motorneurons to record action potentials, which are the characteristic feature of mature neuronal cell. In MSCs-derived neurons, action potentials were not recorded during one-month differentiation period, despite cells exhibited a typical neuronal morphology. Overall, these results suggest that the mRNA signature expressed by the three MSC clones we analyzed corresponds to a limited neuronal potential, so different signatures should be taken into account in a future work.
I follicoli piliferi umani sono una nicchia per diversi tipi di cellule staminali mesenchimali adulte (MSCs) come celulle staminali delle creste neurali e cellule precursori derivate dalla pelle. La capacità delle MSCs di differenziarsi in cellule simil neuroni e gliali è di grande interesse per la medicina rigenerativa, così come per la comprensione dei meccanismi molecolari che intervengono nello sviluppo e nella cura delle neuropatie. Anche se con capacità di differenziamento ridotta, le MSCs hanno indubbiamente dei vantaggi economici rispetto alle cellule staminali riprogrammate (iPSCs); nello stesso tempo, sono già stati osservati i benefici terapeutici in modelli animali di ictus, lesioni del midollo spinale e sclerosi multipla. A partire dal protocollo del laboratorio del Prof. Bortolozzi per l'estrazione, proliferazione e differenziazione di MSCs adulte in neuroni, abbiamo eseguito esperimenti di elettrofisiologia per caratterizzare tre diverse popolazioni monoclonali selezionate da sette attraverso l'analisi del mRNA prima di procedere con il protocollo di differenziazione. La tecnica del patch-clamp è stata usata per depolarizzare singole cellule a differenti stadi di maturazione neuronale per monitorare il potenziale di riposo e la dipendenza dell'attività elettrica dal voltaggio. Per convalidare il protocollo di patch-clamp, abbiamo usato colture primarie di motoneuroni derivati da topi per registrare un potenziale d'azione, che è una caratteristica specifica delle cellule neuronali mature. Nei neuroni derivati da MSCs, il potenziale d'azione non è stato registrato durante un mese di differenziamento, nonostante le cellule esibissero una morfologia tipicamente neuronale. Complessivamente, questi risultati suggeriscono che la caratterizzazione data dal mRNA espressa dai tre cloni che abbiamo analizzato corrisponde ad un potenziale neurologico limitato, quindi differenti caratterizzazioni dovrebbero essere prese in considerazione in un lavoro futuro.ope
Evaluation of the biocompatibility of decellularized porcine myocardium in a preclinical animal model by using rat subcutaneous implant
No full textopenPresupposti dello studio: I disturbi cardiovascolari rappresentano la principale causa di mortalità globale e uno dei principali fattori che contribuiscono alla disabilità. Lo scompenso cardiaco, che può essere considerato la conseguenza finale di quasi la totalità delle affezioni cardiovascolari, ha una prevalenza in Europa dell’1-2% e una mortalità a 5 anni dalla diagnosi, per tutti i tipi di pazienti affetti, del 53-67%, aumentando significativamente negli stadi avanzati di malattia. Attualmente, il gold-standard nel trattamento dello scompenso cardiaco avanzato è rappresentato dal trapianto cardiaco, il quale ha però l’importante limite della scarsità degli organi disponibili. L’ingegneria tissutale rappresenta un valido strumento per offrire in futuro una risposta a tale problematica, ponendosi come obiettivo la rigenerazione del muscolo cardiaco a partire da un cuore porcino decellularizzato e ripopolato con cellule staminali autologhe. Il presente studio si inserisce nell’ambito di un innovativo protocollo di decellularizzazione proposto dal nostro gruppo di ricerca e basato sull’utilizzo del Tergitolo, il quale è risultato essere un ottimo detergente. Per la prima volta, tale protocollo è stato applicato a un cuore porcino intero.
Scopo dello studio: Valutazione dell’efficacia del protocollo di decellularizzazione proposto; valutazione in vivo della biocompatibilità del miocardio porcino decellularizzato, al fine di comprendere se il protocollo di decellularizzazione proposto possa essere applicato per lo sviluppo di scaffolds utilizzabili in ulteriori studi preclinici e, in futuro, in clinica.
Materiali a metodi: Il cuore porcino decellularizzato è stato studiato attraverso estrazione e quantificazione del DNA e analisi istologica, al fine di valutare l’efficacia della decellularizzazione e il danno arrecato alla matrice extracellulare. Per lo studio di biocompatibilità, patches di miocardio porcino prelevati sia dal cuore decellularizzato che da quello nativo, sono stati impiantati nel tessuto sottocutaneo di ratti e successivamente asportati a 1, 4 e 8 settimane. I tessuti espiantati sono stati poi studiati mediante istologia (Ematossilina-Eosina e Tricromica di Masson) e immunofluorescenza (colorazione DAPI nucleo-specifica).
Risultati: Le analisi condotte sullo scaffold decellularizzato hanno mostrato come il protocollo proposto sia efficace in termini di decellularizzazione, riuscendo al tempo stesso a mantenere intatta, dal punto di vista strutturale, la matrice extracellulare. L’analisi istologica e l’immunofluorescenza condotte sui campioni tissutali prelevati dai ratti, previo impianto sottocutaneo dei patches di miocardio decellularizzato, hanno mostrato l’assenza di una risposta infiammatoria e immunitaria a lungo termine e non sono state rilevate alterazioni strutturali nei tessuti dell’ospite.
Conclusioni: Il tessuto decellularizzato ha mostrato proprietà ottimali in termini di biocompatibilità e di biodegradabilità, tali per cui può essere considerato in ulteriori studi preclinici su animali di grossa taglia, nell’implementazione di protocolli di ricellularizzazione, oltre che nello sviluppo di biomateriali ibridi e scaffolds decellularizzati pensati per la rigenerazione del miocardio ischemico o per la realizzazione di modelli di malattia cardiaca.Background: Cardiovascular disorders are the leading cause of global mortality and a major contributor to disability. The prevalence in Europe of heart failure, which can be considered the final consequence in almost all cases of cardiovascular diseases, is 1-2%, with the mortality rate of 53-67% generally after five years after diagnosis in all types of affected patients, and it increases significantly in advanced stages of disease. Currently, the gold-standard in the treatment of advanced heart failure is cardiac transplantation, which, however, has the major limitation of the scarcity of available organs. Tissue engineering represents a valuable tool to answer this problem in the future, aiming at regenerating heart muscle from a decellularized porcine heart repopulated with autologous stem cells. The present study is part of a novel decellularization protocol proposed by our research group and based on the use of Tergitol, which is found to be an efficient detergent. For the first time, this protocol was applied to a whole porcine heart.
Aim of the study: Evaluation of the effectiveness of the proposed decellularization protocol; in vivo evaluation of the biocompatibility of decellularized porcine myocardium, in order to understand if the proposed decellularization protocol can be applied for the development of scaffolds that can be used in further preclinical studies and, in the future, in the clinic
Material and methods: The decellularized porcine heart was studied by DNA extraction and quantification and histological analysis, in order to assess the effectiveness of decellularization and the damage caused to the extracellular matrix. For the biocompatibility study, patches of porcine myocardium taken from both the decellularized and native heart were implanted into the subcutaneous tissue of rats and subsequently explanted at 1, 4 and 8 weeks. The removed tissues were studied by histology (Hematoxylin-Eosin, Masson's Trichrome) and immunofluorescence (nucleus-specific DAPI staining).
Results: Analyses performed on the decellularized scaffold showed that, the proposed protocol is effective in terms of decellularization, while managing to keep the extracellular matrix structurally intact. Histological and immunofluorescence analysis conducted on tissue samples removed from rats, after subcutaneous implantation of the decellularized myocardial patches, showed the absence of a long-term inflammatory and immune response, and no structural alterations in host tissues were detected.
Conclusions: Decellularized tissue has shown optimal properties in terms of biocompatibility and biodegradability, so it can be considered in further preclinical studies in higher animals, in the implementation of recellularization protocols, as well as in the development of hybrid biomaterials and decellularized scaffolds designed for the regeneration of ischemic myocardium or as models of heart disease
"Comparative Evaluation of Novel Detergents for Decellularizing Porcine Coronary Arteries: Toward Non-Toxic, Biocompatible Xenografts for Preclinical Use"
No full textreservedABSTRACT
Background: Cardiovascular diseases have become a very important “killer” in the modern day of medicine/new age of medicine, ranging from ischemic heart diseases to congenital malformations in newborns, as to why it has become a big topic of research worldwide. The potential solution that most of the studies provide are the tissue-engineered vascular grafts, that could bring us to nonimmunogenic grafts and compatible with the patient’s needs, especially the ones who cannot receive a biological, synthetic or autologous graft for various reasons.
Aim of study: in current study, we want to evaluate the efficiency of the selected protocols to produce such the least or non-immunogenic vascular grafts from porcine coronary arteries. We achieved the purpose by applying three different detergents and their particular protocols and compared them based on cell removal and scaffold extracellular matrices preservation.
Materials and methods: The samples (n=3 for each) were divided in three groups each with different detergents (SDS-Tergitol, SDS-Ecosurf and SDS-Triton X100). A separate native group is maintained as control. The decellularized samples were, then, compared with the native coronary samples and with each other by using DNA quantification, histology (e.g. Hematoxylin-Eosin Staining, Masson’s Trichrome, Weigert Van Gieson), Immunofluorescence (Collagen I, Collagen IV, a-GAL M86, Laminin).
Conclusions: The protocols used provided efficient removal of the porcine native cells, leaving the scaffold of the vessels almost intact. This could leave us the possibility to repopulate with stem cells derived endothelial cells to see the regenerative phenomenon for endothelialization. With the least level of immunogenicity, the graft could be used for the preclinical animal models for its biocompatibility. From future prospects, this graft can be proposed to apply in clinical setups without the need of immunosuppressive therapy or the risk of graft rejection.ABSTRACT
Background: Cardiovascular diseases have become a very important “killer” in the modern day of medicine/new age of medicine, ranging from ischemic heart diseases to congenital malformations in newborns, as to why it has become a big topic of research worldwide. The potential solution that most of the studies provide are the tissue-engineered vascular grafts, that could bring us to nonimmunogenic grafts and compatible with the patient’s needs, especially the ones who cannot receive a biological, synthetic or autologous graft for various reasons.
Aim of study: in current study, we want to evaluate the efficiency of the selected protocols to produce such the least or non-immunogenic vascular grafts from porcine coronary arteries. We achieved the purpose by applying three different detergents and their particular protocols and compared them based on cell removal and scaffold extracellular matrices preservation.
Materials and methods: The samples (n=3 for each) were divided in three groups each with different detergents (SDS-Tergitol, SDS-Ecosurf and SDS-Triton X100). A separate native group is maintained as control. The decellularized samples were, then, compared with the native coronary samples and with each other by using DNA quantification, histology (e.g. Hematoxylin-Eosin Staining, Masson’s Trichrome, Weigert Van Gieson), Immunofluorescence (Collagen I, Collagen IV, a-GAL M86, Laminin).
Conclusions: The protocols used provided efficient removal of the porcine native cells, leaving the scaffold of the vessels almost intact. This could leave us the possibility to repopulate with stem cells derived endothelial cells to see the regenerative phenomenon for endothelialization. With the least level of immunogenicity, the graft could be used for the preclinical animal models for its biocompatibility. From future prospects, this graft can be proposed to apply in clinical setups without the need of immunosuppressive therapy or the risk of graft rejection
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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