Página 1 dos resultados de 12687 itens digitais encontrados em 0.040 segundos

Identification of hepatic stem/progenitor cells in canine hepatocellular and cholangiocellular carcinoma

COGLIATI, B.; ALOIA, T. P. A.; BOSCH, R. V.; ALVES, V. A. F.; HERNANDEZ-BLAZQUEZ, F. J.; DAGLI, M. L. Z.
Fonte: WILEY-BLACKWELL Publicador: WILEY-BLACKWELL
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.13%
Hepatic progenitor cells (HPCs) are bipotential stem cells residing in human and animal livers that are able to differentiate towards the hepatocytic or cholangiocytic lineages. HPCs are present in both hepatocellular (HCC) and cholangiocellular carcinoma (CC) in humans; and a small percentage of HCC can originate from cancer stem cells. However, its distribution in canine liver tumour has not been studied. Herein, we searched for stem/progenitor cells in 13 HCC and 7 CC archived samples by immunohistochemical analysis. We found that both liver tumours presented a higher amount of K19-positive HPCs. Besides, 61.6% of HCC cases presented immature CD44-positive hepatocytes. Nevertheless, only two cases presented CD133-positive cells. As observed in humans, hepatic canine tumours presented activated HPCs, with important differentiation onto hepatocytes-like cells and minimal role of cancer stem cells on HCC. These findings reiterate the applicability of canine model in the search for new therapies before application in humans.; Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)[05/05138-6]

Equivalent Neurogenic Potential of Wild-Type and GFP-Labeled Fetal-Derived Neural Progenitor Cells Before and After Transplantation Into the Rodent Hippocampus

LEPSKI, Guilherme; JANNES, Cinthia E.; WESSOLLECK, Johanna; KOBAYASHI, Eiji; NIKKHAH, Guido
Fonte: LIPPINCOTT WILLIAMS & WILKINS Publicador: LIPPINCOTT WILLIAMS & WILKINS
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.05%
Introduction. The hippocampal formation is a specific structure in the brain where neurogenesis occurs throughout adulthood and in which the neuronal cell loss causes various demential states. The main goal of this study was to verify whether fetal neural progenitor cells (NPCs) from transgenic rats expressing green fluorescent protein (GFP) retain the ability to differentiate into neuronal cells and to integrate into the hippocampal circuitry after transplantation. Methods. NPCs were isolated from E14 (gestational age: 14 days postconception) transgenic-Lewis and wild-type Sprague-Dawley rat embryos. Wild-type and transgenic cells were expanded and induced to differentiate into a neuronal lineage in vitro. Immunocytochemical and electrophysiological analysis were performed in both groups. GFP-expressing cells were implanted into the hippocampus and recorded electrophysiologically 3 months thereafter. Immunohistochemical analysis confirmed neuronal differentiation, and the yield of neuronal cells was determined stereologically. Results. NPCs derived from wild-type and transgenic animals are similar regarding their ability to generate neuronal cells in vitro. Neuronal maturity was confirmed by immunocytochemistry and electrophysiology...

Role of NFKB2 on the early myeloid differentiation of CD34+ hematopoietic stem/progenitor cells

MOLFETTA, Greice Andreotti De; ZANETTE, Dalila Luciola; PANEPUCCI, Rodrigo Alexandre; SANTOS, Anemarie Ramos Dinarte dos; SILVA JR., Wilson Araujo da; ZAGO, Marco Antonio
Fonte: ELSEVIER SCI LTD Publicador: ELSEVIER SCI LTD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
66.01%
To better understand the early events regulating lineage-specific hematopoietic differentiation, we analyzed the transcriptional profiles of CD34+ human hematopoietic stem and progenitor cells (HSPCs) subjected to differentiation stimulus. CD34+ cells were cultured for 12 and 40 h in liquid cultures with supplemented media favoring myeloid or erythroid commitment. Serial analysis of gene expression (SAGE) was employed to generate four independent libraries. By analyzing the differentially expressed regulated transcripts between the un-stimulated and the stimulated CD34+ cells, we observed a set of genes that was initially up-regulated at 12 h but were then down-regulated at 40 h, exclusively after myeloid stimulus. Among those we found transcripts for NFKB2, RELB, IL1B, LTB, LTBR, TNFRSF4, TGFB1, and IKBKA. Also, the inhibitor NFKBIA (IKBA) was more expressed at 12 h. All those transcripts code for signaling proteins of the nuclear factor kappaB pathway. NFKB2 is a subunit of the NF-kappa B transcription factor that with RELB mediates the non-canonical NF-kappa B pathway. Interference RNA (RNAi) against NFKB1, NFKB2 and control RNAi were transfected into bone marrow CD34+HSPC. The percentage and the size of the myeloid colonies derived from the CD34+ cells decreased after inhibition of NFKB2. Altogether...

Caracterização das Células-Tronco/Progenitoras Hematopoéticas obtidas de Células-Tronco Embrionárias Humanas In Vitro em Sistema de Co-Cultivo com Fibroblastos de Embriões Murinos.; Characterization of Hematopoietic Stem/Progenitor Cells Obtained In Vitro from Human Embryonic Stem Cells in Co-Culture System with Mouse Embryonic Fibroblasts.

Costa, Everton de Brito Oliveira
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 04/06/2012 PT
Relevância na Pesquisa
66.11%
A hematopoese tem sido bem descrita em modelos murinos nas últimas décadas, contudo, trabalhos demonstrando os mecanismos da hematopoese em humanos ainda são escassos. A derivação da primeira linhagem de células-tronco embrionárias humanas (CTEhs) em 1998, gerou novas perspectivas tanto para o estudo da hematopoese na tentativa de mimetizar o que ocorre naturalmente durante o desenvolvimento embrionário, quanto para a aplicação clínica das células hematopoéticas obtidas a partir da diferenciação dessas células. Contudo, apesar de inúmeros trabalhos terem demonstradoa obtenção de células hematopoéticas a partir de CTEhs, os protocolos têm gerado quantidades variáveis de células, com baixa eficiência e com propriedades funcionais de células primitivas. Desse modo, este trabalho procurou estabelecer um modelo próprio de diferenciação de CTEhs-H1 em células progenitoras hematopoéticas para que estas pudessem ser melhor caracterizadas e obtidas de forma mais eficiente. Para isto, foi desenvolvido um sistema de diferenciação baseado no co-cultivo da linhagem de CTEh-H1 com fibroblastos de embrião de camundongo (MEFs), em meio de diferenciação suplementado soro fetal bovino (SFB) e citocinas e fatores de crescimento hematopoéticos em baixas concentrações. Como resultado...

Characterization of Neural Stem/Progenitor Cells Expressing VEGF and its Receptors in the Subventricular Zone of Newborn Piglet Brain

Ara, Jahan; Fekete, Saskia; Zhu, Anli; Frank, Melissa
Fonte: Springer/plenum Publishers Publicador: Springer/plenum Publishers
Tipo: Artigo de Revista Científica Formato: 1455-1470
ENG
Relevância na Pesquisa
66.07%
Neural stem/progenitor cell (NSP) biology and neurogenesis in adult central nervous system (CNS) are important both towards potential future therapeutic applications for CNS repair, and for the fundamental function of the CNS. In the present study, we report the characterization of NSP population from subventricular zone (SVZ) of neonatal piglet brain using in vivo and in vitro systems. We show that the nestin and vimentin-positive neural progenitor cells are present in the SVZ of the lateral ventricles of neonatal piglet brain. In vitro, piglet NSPs proliferated as neurospheres, expressed the typical protein of neural progenitors, nestin and a range of well-established neurodevelopmental markers. Upon dissociation and subculture, piglet NSPs differentiated into neurons and glial cells. Clonal analysis demonstrates that piglet NSPs are multi-potent and retain the capacity to generate both glia and neurons. These cells expressed VEGF, VEGFR1, VEGFR2 and Neuropilin-1 and -2 mRNAs. Real time PCR revealed that SVZ NSPs from newborn piglet expressed total VEGF and all VEGF splice variants. These findings show that piglet NSPs may be helpful to more effectively design growth factor based strategies to enhance endogenous precursor cells for cell transplantation studies potentially leading to the application of this strategy in the nervous system disease and injury.

Biology and clinical utilization of mesenchymal progenitor cells

Minguell,J.J.; Conget,P.; Erices,A.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2000 EN
Relevância na Pesquisa
66.02%
Within the complex cellular arrangement found in the bone marrow stroma there exists a subset of nonhematopoietic cells referred to as mesenchymal progenitor cells (MPC). These cells can be expanded ex vivo and induced, either in vitro or in vivo, to terminally differentiate into at least seven types of cells: osteocytes, chondrocytes, adipocytes, tenocytes, myotubes, astrocytes and hematopoietic-supporting stroma. This broad multipotentiality, the feasibility to obtain MPC from bone marrow, cord and peripheral blood and their transplantability support the impact that the use of MPC will have in clinical settings. However, a number of fundamental questions about the cellular and molecular biology of MPC still need to be resolved before these cells can be used for safe and effective cell and gene therapies intended to replace, repair or enhance the physiological function of the mesenchymal and/or hematopoietic systems.

Effects of simvastatin/ezetimibe on microparticles, endothelial progenitor cells and platelet aggregation in subjects with coronary heart disease under antiplatelet therapy

Camargo,L.M.; França,C.N.; Izar,M.C.; Bianco,H.T.; Lins,L.S.; Barbosa,S.P.; Pinheiro,L.F.; Fonseca,F.A.H.
Fonte: Associação Brasileira de Divulgação Científica Publicador: Associação Brasileira de Divulgação Científica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/05/2014 EN
Relevância na Pesquisa
66.09%
It is not known whether the addition of ezetimibe to statins adds cardiovascular protection beyond the expected changes in lipid levels. Subjects with coronary heart disease were treated with four consecutive 1-week courses of therapy (T) and evaluations. The courses were: T1, 100 mg aspirin alone; T2, 100 mg aspirin and 40 mg simvastatin/10 mg ezetimibe; T3, 40 mg simvastatin/10 mg ezetimibe, and 75 mg clopidogrel (300 mg initial loading dose); T4, 75 mg clopidogrel alone. Platelet aggregation was examined in whole blood. Endothelial microparticles (CD51), platelet microparticles (CD42/CD31), and endothelial progenitor cells (CD34/CD133; CDKDR/CD133, or CD34/KDR) were quantified by flow cytometry. Endothelial function was examined by flow-mediated dilation. Comparisons between therapies revealed differences in lipids (T2 and T3T1 and T4, P=0.001). Decreased platelet aggregation was observed after aspirin (arachidonic acid, T1

Lung Epithelial Progenitor Cells: Lessons from Development

Rawlins, Emma L.
Fonte: American Thoracic Society Publicador: American Thoracic Society
Tipo: Artigo de Revista Científica
Publicado em 15/08/2008 EN
Relevância na Pesquisa
66.08%
The current enthusiasm for stem cell research stems from the hope that damaged or diseased tissues may one day be repaired through the manipulation of endogenous or exogenous stem cells. The postnatal human respiratory system is highly accessible and provides unique opportunities for the application of such techniques. Several putative adult lung epithelial stem cells have been identified in the mouse model system. However, their in vivo capabilities to contribute to different lineages, and their control mechanisms, remain unclear. If stem cell–based therapies are to be successful in the lung, it is vitally important that we understand the normal behavior of adult lung stem cells, and how this is regulated. Lung embryonic progenitor cells are much better defined and characterized than their adult counterparts. Moreover, experiments on a variety of developing tissues are beginning to uncover general mechanisms by which embryonic progenitors influence final organ size and structure. This provides a framework for the study of lung embryonic progenitor cells, facilitating experimental design and interpretation. A similar approach to investigating adult lung stem cells could produce rapid advances in the field.

Stem/Progenitor Cells in Lung Development, Injury Repair, and Regeneration

Warburton, David; Perin, Laura; DeFilippo, Roger; Bellusci, Saverio; Shi, Wei; Driscoll, Barbara
Fonte: American Thoracic Society Publicador: American Thoracic Society
Tipo: Artigo de Revista Científica
Publicado em 15/08/2008 EN
Relevância na Pesquisa
66.18%
At least two populations of epithelial stem/progenitor cells give rise to the lung anlage, comprising the laryngo-tracheal complex versus the distal lung below the first bronchial bifurcation. Amplification of the distal population requires FGF9-FGF10-FGFR2b-Sprouty signaling. Residual pools of adult stem cells are hypothesized to be the source of lung regeneration and repair. These pools have been located within the basal layer of the upper airways, within or near pulmonary neuroendocrine cell rests, at the bronchoalveolar junction as well as within the alveolar epithelial surface. Rapid repair of the denuded alveolar surface after injury is clearly key to survival. Strategies to enhance endogenous alveolar epithelial repair could include protection of epithelial progenitors from injury and/or stimulation of endogenous progenitor cell function. Protection with inosine or FGF signaling are possible small molecule therapeutic options. Alternatively, exogenous stem/progenitor cells can be delivered into the lung either intravenously, intratracheally, or by direct injection. Sources of exogenous stem/progenitor cells that are currently under evaluation in the context of acute lung injury repair include embryonic stem cells, bone marrow– or fat-derived mesenchymal stem cells...

Mechanisms of oligodendrocyte regeneration from ventricular-subventricular zone-derived progenitor cells in white matter diseases

Maki, Takakuni; Liang, Anna C.; Miyamoto, Nobukazu; Lo, Eng H.; Arai, Ken
Fonte: Frontiers Media S.A. Publicador: Frontiers Media S.A.
Tipo: Artigo de Revista Científica
EN_US
Relevância na Pesquisa
66.15%
White matter dysfunction is an important part of many CNS disorders including multiple sclerosis (MS) and vascular dementia. Within injured areas, myelin loss and oligodendrocyte death may trigger endogenous attempts at regeneration. However, during disease progression, remyelination failure may eventually occur due to impaired survival/proliferation, migration/recruitment, and differentiation of oligodendrocyte precursor cells (OPCs). The ventricular-subventricular zone (V-SVZ) and the subgranular zone (SGZ) are the main sources of neural stem/progenitor cells (NSPCs), which can give rise to neurons as well as OPCs. Under normal conditions in the adult brain, the V-SVZ progenitors generate a large number of neurons with a small number of oligodendrocyte lineage cells. However, after demyelination, the fate of V-SVZ-derived progenitor cells shifts from neurons to OPCs, and these newly generated OPCs migrate to the demyelinating lesions to ease white matter damage. In this mini-review, we will summarize the recent studies on extrinsic (e.g., vasculature, extracellular matrix (ECM), cerebrospinal fluid (CSF)) and intrinsic (e.g., transcription factors, epigenetic modifiers) factors, which mediate oligodendrocyte generation from the V-SVZ progenitor cells. A deeper understanding of the mechanisms that regulate the fate of V-SVZ progenitor cells may lead to new therapeutic approaches for ameliorating white matter dysfunction and damage in CNS disorders.

“Potential biological meaning and origin of cardiac progenitor cells isolated as Cardiospheres"

FORTE, ELVIRA
Fonte: La Sapienza Universidade de Roma Publicador: La Sapienza Universidade de Roma
Tipo: Tese de Doutorado
EN_US
Relevância na Pesquisa
66.1%
Several populations of progenitor cells have been identified in the adult heart, based on the expression of specific surface markers (c-kit, Sca1), or on functional properties, such as the ability to spontaneously migrate from tissue explants and grow in three dimensional structures, called cardiospheres (CSs). CSs represent a niche-like microtissue with a cardiogenic gradient of differentiation towards the periphery. It is not clear which is the origin of these endogenous progenitor populations and how they function in vivo, given the limited regenerative capacity of the heart. Several possibilities can be envisioned. These cells could be remnants of the embryonic development, or derive from the de-differentiation of cardiomyocytes. To test this hypothesis we used a double transgenic mouse expressing the recombinase MerCreMer under the cardiomyocyte-specific αMyosin-Heavy-Chain promoter. After a pulse with 4OH-tamoxifen (TAM) the activated Cre removes a stop signal between two LoxP sequences, allowing the expression of the reporter gene LacZ, in a spatial and temporal regulated manner. Ideally with this system all the differentiated cardiomyocytes should be irreversibly labeled after TAM treatment, even if they subsequently undergo de-differentiation. B-gal positive cells were very rare in culture...

Endothelial progenitor cells enhance islet engraftment, influence β-cell function and modulate islet connexin 36 expression; Endothelial progenitor cells enhance islet engraftment, influence beta-cell function and modulate islet connexin 36 expression

Penko, D.; Rojas-Canales, D.; Mohanasundaram, D.; Peiris, H.; Sun, W.; Drogemuller, C.; Keating, D.; Coates, P.; Bonder, C.; Jessup, C.
Fonte: Cognizant Communication Corporation Publicador: Cognizant Communication Corporation
Tipo: Artigo de Revista Científica
Publicado em //2015 EN
Relevância na Pesquisa
66.06%
The success of pancreatic islet transplantation is limited by delayed engraftment and suboptimal function in the longer term. Endothelial progenitor cells (EPCs) represent a potential cellular therapy that may improve the engraftment of transplanted pancreatic islets. In addition, EPCs may directly affect the function of pancreatic β-cells. The objective of this study was to examine the ability of EPCs to enhance pancreatic islet transplantation in a murine syngeneic marginal mass transplant model and to examine the mechanisms through which this occurs. We found that cotransplanted EPCs improved the cure rate and initial glycemic control of transplanted islets. Gene expression data indicate that EPCs, or their soluble products, modulate the expression of the β-cell surface molecule connexin 36 and affect glucose-stimulated insulin release in vitro. In conclusion, EPCs are a promising candidate for improving outcomes in islet transplantation, and their mechanisms of action warrant further study.; Daniella Penko, Darling Rojas-Canales, Daisy Mohanasundaram, Heshan S. Peiris, Wai Y. Sun, Christopher J. Drogemuller, Damien J. Keating, P. Toby H. Coates, Claudine S. Bonder, and Claire F. Jessup

Vascular wall progenitor cells in health and disease

Psaltis, P.J.; Simari, R.D.
Fonte: American Heart Association Publicador: American Heart Association
Tipo: Artigo de Revista Científica
Publicado em //2015 EN
Relevância na Pesquisa
66.21%
The vasculature plays an indispensible role in organ development and maintenance of tissue homeostasis, such that disturbances to it impact greatly on developmental and postnatal health. Although cell turnover in healthy blood vessels is low, it increases considerably under pathological conditions. The principle sources for this phenomenon have long been considered to be the recruitment of cells from the peripheral circulation and the re-entry of mature cells in the vessel wall back into cell cycle. However, recent discoveries have also uncovered the presence of a range of multipotent and lineage-restricted progenitor cells in the mural layers of postnatal blood vessels, possessing high proliferative capacity and potential to generate endothelial, smooth muscle, hematopoietic or mesenchymal cell progeny. In particular, the tunica adventitia has emerged as a progenitor-rich compartment with niche-like characteristics that support and regulate vascular wall progenitor cells. Preliminary data indicate the involvement of some of these vascular wall progenitor cells in vascular disease states, adding weight to the notion that the adventitia is integral to vascular wall pathogenesis, and raising potential implications for clinical therapies. This review discusses the current body of evidence for the existence of vascular wall progenitor cell subpopulations from development to adulthood and addresses the gains made and significant challenges that lie ahead in trying to accurately delineate their identities...

Funktionelle Untersuchung der zytotoxischen Aktivität von Natürlichen Killerzellen in Abhängigkeit von der HLA Klasse I Expression auf erythroiden Vorläuferzellen; Funktionelle Untersuchung der zytotoxischen Aktivität von Natürlichen Killerzellen in Abhängigkeit von der HLA Klasse I Expression auf erythroiden Vorläuferzellen; Functional investigation of natural killer cells cytolytic activity depending on human leucocty antigen class I expression on erythropietic progenitor cells

Engels, Eva-Maria
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
DE_DE
Relevância na Pesquisa
66.15%
Einleitung: Diese Arbeit entstand aus der Beobachtung heraus, dass NK-Zellen (natürliche Killerzellen) und CTL (zytotoxische T-Lymphozyten) vom gamma/delta-Typ eine zytotoxische Aktivität in der Abwesenheit von HLA-I (Humanes Leukozyten Antigen Klasse I) zeigen. Fragestellung: Ein Ziel dieser Arbeit war es erythroide Vorläuferzellen zu kultivieren, um die HLA-I Expression an der Oberfläche in einem Zeitraum von 14 Tagen zu verfolgen. Lassen sich unterschiede in der zytotoxischen Funktion von NK-Zellen gegen HLA-I+ (granulo-/monozytäre) und HLA-I– (erythroide) Zellen nachweisen und bestehen Unterschiede in der Funktion von NK-Zellen im autologen bzw. allogenen System? Methoden: CD34+, CD56+ und Glykophorin A+ Zellen wurden mittels MACS Methode angereichert. CD34+ Zellen wurden in einem semi-soliden Medium 14 Tage kultiviert. Die Reinheit der Zellen sowie die HLA-I Expression wurde mit der FASC Methode analysiert und dokumentiert. Mit dem Europiumfreisetzungstest wurde die Zytotoxizität von NK-Zellen gegen HLA-I+ und HLA-I– Zellen untersucht. Ergebnisse: Es konnte eine Tendenz dahingehend beobachtet werden, dass erythoride Vorläuferzellen nach 14 Tagen weniger HLA-I exprimierten als an Tag 8. Bei granulo-/monozytären Vorläuferzellen blieb die HLA-I Expression über 14 Tage weitgehend konstant. Im Vergleich zu den CD 34+ Stammzellen exprimierten beide Zellreihen deutlich weniger HLA-I. Unterschiede in der Zytotoxizität von NK-Zellen konnte weder zwischen HLA-I+ und HLA-I– noch zwischen autologem und allogenem System beobachtet werden. Schlußfolgerung: Bei der in dieser Arbeit gewählten Versuchsanordnung konnte weder im allogenen noch im autologen System eine zytotoxische Aktivität von NK-Zellen beobachtet werden. Um genauere Aussagen machen zu können hätte...

Die Expression von Junctional Adhesion Molecule-A auf humanen CD34+ Zellen fördert deren Adhäsion und Differenzierung zu endothelialen Progenitorzellen; Junctional adhesion molecule A expressed on human CD34+ cells promotes adhesion and differentiation into endothelial progenitor cells

Gnerlich, Stephan Matthias
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
DE_DE
Relevância na Pesquisa
66.22%
Hintergrund: Geweberegeneration und Gefäßreparatur sowie die Neoangiogenese, z.B. nach Myokardinfarkt, sind Kaskaden, die eine initiale Festadhäsion zirkulierender Progenitorzellen an die Gefäßwand und im Anschluss eine Differenzierung jener Progenitorzellen zu Endothelzellen beinhalten. Es wurde bereits in der Literatur beschrieben, dass Thrombozyten, die ersten Zellen an Ort und Stelle eines Gefäßschadens, diese zirkulierenden Progenitorzellen rekrutieren und dass sie auf ihrer Oberfläche unter anderem Junctional Adhesion Molecule-A (JAM-A) exprimieren. JAM-A ist ein Zelladhäsionsmolekül, das bekanntermaßen am Aufbau von Tight-Junctions beteiligt ist und auch bei Entzündungsreaktionen eine Rolle spielt. Das Ziel der vorliegenden Arbeit war es, die Rolle von JAM-A in der von Thrombozyten induzierten Adhäsion und konsekutiven Differenzierung humaner CD34+ Progenitorzellen zu endothelialen Vorläuferzellen zu evaluieren. Methoden und Ergebnisse: CD34+ Zellen adhärieren auf immobilisierten Thrombozyten unter statischen- sowie unter dynamischen Bedingungen, wie wir in statischen Adhäsions Assays und in der Flusskammer zeigen konnten. Die Rolle von JAM-A in der von Thrombozyten induzierten Adhäsion wurde dabei durch neutralisierende lösliche Proteine (sJAM-A-Fc) und blockierende monoklonale Antikörper (anti-JAM-A) untersucht. Vorinkubationen mit sJAM-A-Fc oder aber anti-JAM-A resultierten dabei in einer signifikant erniedrigten Adhäsion humaner CD34+ Zellen an Thrombozyten. Humane CD34+ Zellen exprimieren weiterführend selbst in hohem Maße JAM-A...

Nachweis von eisenmarkierten hämatopoietischen Vorläuferzellen im Agarphantom mittels hochauflösender MR-Tomographie; Detection of iron-labelled hematopoietic progenitor cells in agar phantoms via high-resolution MR-Tomography

Kramberg, Sebastian
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
DE_DE
Relevância na Pesquisa
66.08%
Ziele: Untersuchung und Optimierung der Eisenmarkierung von hämatopoietischen Vorläuferzellen hinsichtlich klinischer Anforderungen beim Monitoring zellulärer Therapien. Material und Methoden: Als Stammzellmodell dienten CD34+ KG-1A-Suspensionszellen. Diese wurden zu unterschiedlichen Zeit- und Konzentrationsbedingungen mit Ferucarbotran (Resovist®)markiert (ohne als auch unter zusätzlicher Verwendung eines liposomalen (DOSPER) bzw. nichtliposomalen Transfektionsagens (JetPEI)). Der Eisengehalt pro Zelle wurde photometrisch bestimmt. Die MR-Untersuchungen erfolgten in Agarphantomen am Hochfeldtomographen (TimTrio [3.0T]). Die Verteilung des Kontrastmittels an bzw. in der Zelle wurde elektronen-mikroskopisch untersucht. Zur Bestimmung der Zellvitalität wurden Proliferationskinetiken durchgeführt und die Apoptoserate durchflußzytometrisch bestimmt. Ergebnisse: Die Fe-Aufnahme der Zellen ist abhängig von der Fe-Konzentration im Medium sowie der Inkubationszeit. Die maximale Eisenaufnahme beträgt ca. 100 pg/Zelle. Unter zusätzlicher Verwendung von Transfektionsagenzien (JetPEI und DOSPER) lässt sich - bei gleicher kernspintomographischer Signalauslöschung - die Eisenmenge im Medium um mindestens das 8fache und die Inkubationszeit um mindestens das 12fache reduzieren. Proliferierende Zellen lassen sich noch mindestens 10 Tage nach erfolgter Eisenmarkierung kernspintomographisch nachweisen. Schlußfolgerungen: Hämatopoietische Vorläuferzellen lassen sich ohne Einschränkung der Proliferationsfähigkeit und Vitalität effektiv mit auf Ferrit basierenden Kontrastmitteln beladen und kernspintomographisch detektieren. Durch Verwendung von Transfektionsagentien lässt sich die benötigte Eisenmenge und die Inkubationszeit signifikant verringern...

Der Einfluss des CysLT1 Liganden Leukotrien D4 auf Adhäsion und Proliferation CD34+ hämatopoetischer Progenitorzellen; The CysLT1 ligand leukotriene D4 supports adhesion and proliferation of CD34+ hematopoietic progenitor cells.

Jaggy, Lena
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
DE_DE
Relevância na Pesquisa
66.14%
Die Fähigkeit der Stammzellen das Knochenmark zu verlassen und es anschließend zielgerichtet wiederzubesiedeln, zu proliferieren und somit die Hämatopoese wiederherzustellen stellt die Voraussetzung einer erfolgreichen Transplantation dar. Im Gegensatz zu der bereits bekannten Rolle die hierbei Proteine und Peptide spielen, ist die Funktion von Lipidmediatoren noch nicht vollständig geklärt. Insbesondere CysLT1, ein G-Protein gekoppelter Rezeptor wird von hämatopoetischen Progenitorzellen exprimiert. Um die Wirkung der Cysteinyl-Leukotriene zu untersuchen wurde der CysLT1-Rezeptor mit verschiedenen Liganden (LTD4, LTE4 und LTC4) stimuliert. LTD4 stellte sich als CysLT1-Ligand mit dem stärksten Effekt heraus. Der Effekt der anderen CysLT1-Liganden war sehr gering (LTC4), bzw. nicht vorhanden (LTE4). Die durch Leukotrien induzierte Adhäsion hämatopoetischer Stammzellen konnte in anschließenden Versuchen inhibiert werden. Durch Inhibition der Adhäsion mittels dem Tyrosinkinaseinhibitior Genistein konnte die mögliche Beteiligung der Proteinkinase gezeigt werden, wobei hier ein unspezifischer Effekt nicht eindeutig ausgeschlossen werden kann. Verschiedene CysLT1-Rezeptorantagonisten, wie Ly171883 oder MK-571 demonstrierten die Beteiligung des CysLT1-Rezeptors bei der LTD4 induzierten Adhäsion hämatopoetischer Stammzellen. Außerdem konnte durch PD98059 die Beteiligung des MEK/ERK/MAPK Signalwegs an der CysLT1 Signaltransduktion gezeigt werde. In serumfreiem...

Charakterisierung leukämischer Progenitorzellen im NOD/SCID-Mausmodell mittels Hoechst 33342; Characterization of leukemic progenitor cells in the NOD/SCID mouse model using Hoechst 33342

Hörrmann, Reinhard
Fonte: Universidade de Tubinga Publicador: Universidade de Tubinga
Tipo: Dissertação
DE_DE
Relevância na Pesquisa
66.26%
Zusammenfassung der Dissertation von Reinhard Hörrmann Titel: Charakterisierung leukämischer Progenitorzellen im NOD/SCID-Mausmodell mittels Hoechst 33342 Man geht davon aus, dass Leukämien auf genetisch veränderte HSC oder auf Zellen, welche Eigenschaften von HSC wiedererlangen, zurückzuführen sind. In vielen Fällen ist nur eine kleine Population von leukämischen Stammzellen zur Selbsterneuerung, Proliferation und Differenzierung fähig. Das heißt, nur diese Zellen sind fähig, alle Zellen einer Leukämie zu generieren und spielen somit eine entscheidende Rolle bei der Entstehung und Erhaltung einer Leukämie. Diese unreifen leukämischen Progenitorzellen haben bestimmte Eigenschaften, wie dem Verharren in einem Art Ruhezustand (G0-Phase des Zellzyklus) und dem Besitz von membranständigen Transporterproteinen (Effluxpumpen), mit welchen sie toxische Substanzen aktiv aus der Zelle transportieren können und dadurch besonders widerstandsfähig gegen Chemotherapeutika sind. Somit scheinen die leukämischen Progenitorzellen einen entscheidenden Beitrag bei der Initiierung eines Rezidivs zu spielen. Daher ist es von besonderem Interesse und Bestandteil dieser Arbeit, die leukämischen Progenitorzellen nachzuweisen und dadurch mögliche Targets zu finden...

Stem Cells and Progenitor Cells for Tissue-Engineered Solutions to Congenital Heart Defects

Gao, Yang; Jacot, Jeffrey G.
Fonte: Universidade Rice Publicador: Universidade Rice
Tipo: Journal article; Text; publisher version
ENG
Relevância na Pesquisa
66.05%
Synthetic patches and fixed grafts currently used in the repair of congenital heart defects are nonliving, noncontractile, and not electrically responsive, leading to increased risk of complication, reoperation, and sudden cardiac death. Studies suggest that tissue-engineered patches made from living, functional cells could grow with the patient, facilitate healing, and help recover cardiac function. In this paper, we review the research into possible sources of cardiomyocytes and other cardiac cells, including embryonic stem cells, induced pluripotent stem cells, mesenchymal stem cells, adipose-derived stem cells, umbilical cord blood cells, amniotic fluid-derived stem cells, and cardiac progenitor cells. Each cell source has advantages, but also has technical hurdles to overcome, including heterogeneity, functional maturity, immunogenicity, and pathogenicity. Additionally, biomaterials used as patch materials will need to attract and support desired cells and induce minimal immune responses.

Criopreservação de células-progenitoras hematopoéticas; Cryopreservation of hematopoietic progenitor cells

Santis, Gil Cunha; Prata, Karen Lima
Fonte: Universidade de São Paulo. Faculdade de Medicina de Ribeirão Preto Publicador: Universidade de São Paulo. Faculdade de Medicina de Ribeirão Preto
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; Formato: application/pdf
Publicado em 30/03/2009 POR
Relevância na Pesquisa
66.07%
O transplante autólogo de células-progenitoras hematopoéticas (CPH) requer, na maioria das vezes, a sua criopreservação a fim de manter sua viabilidade até o momento da infusão, que pode se dar meses ou anos depois da coleta. A criopreservação adequada das CPHs é feita ao submeter a suspensão celular a velocidades lentas de congelamento (1 a 3ºC/minuto), e com o  emprego de substâncias chamadas crioprotetoras, sendo a mais usada o dimetilsulfóxido (MeSO4), um agente coligativo que diminui o conteúdo de água livre tanto no espaço intra como no extracelular. Portanto, este composto diminui o tamanho e o número dos cristais de gelo. O descongelamento das CPHs é feito rapidamente.A suspensão celular pode então ser infundida sem posterior manipulação ou ser submetida a lavagem para remover o MeSO4, restos celulares e hemoglobina livre, potencialmente tóxicos tanto para o paciente quanto para as células. ; Autologous transplantation of hematopoietic progenitor cells requires most of the times the cryopreservation of the hematopoietic progenitor cells (HPC) to maintain their viability until the infusion, which can occur months to years after their collection. Adequate cryopreservation of HPC is realized by submitting the cells to slow freezing velocity (1-3°C/minute) and by employing cryoprotectant agents like the dimethylsulphoxide (Me2SO4)...