1,720,967 research outputs found
A new standardized clinical-grade protocol for banking human umbilical cord tissue cells
No full textBACKGROUND: Mesenchymal stromal cells (MSCs) isolated from human umbilical cord
tissue (UCT) can be considered the perfect candidates for cell-based therapies
and regenerative medicine. UCT-derived MSCs can be cryogenically stored in cell
banks and expanded as needed for therapeutic uses.
STUDY DESIGN AND METHODS: We developed a new method for UCT-MSC isolation,
cryopreservation, and expansion, following all criteria required by a stem cell
bank. UCT-MSCs were isolated either by manual dissociation (MM) or by a
semiautomatic dissociation system (SAM). In both protocols UCTs were treated
enzymatically using Type IV collagenase good manufacturing practices (GMP) graded
and hyaluronidase (medicinal product). Isolated UCT-MSCs were cryopreserved and
analyzed after thawing for phenotype; for proliferation rate; and for their
osteogenic, adipogenic, and chondrogenic differentiation capabilities.
RESULTS: We found that SAM reduced the time of tissue enzyme exposure and enabled
us to obtain a homogeneous single-cell suspension deprived of tissue fragments.
The isolated cells in both groups showed high expression of MSC markers CD105,
CD73, and CD90 and similar differentiation capabilities, phenotype, and
proliferation potential. Moreover, the final yield of MSCs was comparable between
the two techniques.
CONCLUSION: In this study, we have established a reliable and standardized
protocol to isolate UCT-MSCs from UCT for cell banking purposes. Processing the
whole umbilical tissue with GMP-graded enzymes using a semiautomatic dissociator
allowed us to obtain a single-cell suspension product with a known number of
isolated cells that can be cryopreserved right after isolation and thawed as
needed for expansion and clinical use
Impact of infectious agents on trafficking of effector T cells is mediated by a polymorphic site of TLR2.
No full textThe role of infectious agents in the regulation of antigen-specific T cell trafficking is currently unknown. Here we report evidence that the amount of M tuberculosis in the adjuvant modulates rapid relocation of PLP139-151 (p139)-specific T cells carrying the public TCR-beta chain BV1-CASS SGS NTE JB1.1 from draining lymph nodes (LN) to spleen, in the SJL mouse. In fact, T cells of mice immunized in the presence of a low dose of M tuberculosis mostly reached the spleen by day 28 after immunization (“late relocation”), whereas a high dose of M tuberculosis in the adjuvant promoted relocation of T cells to the spleen already by d 14 after immunization (“early relocation”). Modulation of T cell mobilization was strain-dependent with the C57/Bl6 background conferring a dominant “early relocation” phenotype to F1 (SJL x C57/Bl6) mice, allowing early relocation of T cells to the spleen also in the presence of low dose M tuberculosis. T cells from F1 (SJL x C57/Bl6tlr2-) mice that displayed only functional TLR2 of SJL origin did not relocate to the spleen at day 14 post-immunization in the presence of low dose of M tuberculosis, suggesting that TLR2 of C57/Bl6 origin confers the early relocation phenotype to F1 (SJL x C57/Bl6) mice. One non-synonymous polymorphism exists between TLR2 of SJL and of C57/BL6. F1 (SJLxC57/Bl6) mice homozygous for TLR2 of SJL display the same “late relocation” phenotype of F1 (SJL x C57/Bl6tlr2-) heterozygous littermates, formally proving that this polymorphism is responsible for “early/late” relocation phenotype. By transferring T cells from F1 mice obtained crossing SJL mice transgenic for the mentioned TCR-beta chain of the p139-specific, public receptor (SJLBV10) with C57/Bl6wt or C57/Bl6tlr2-, we determined that egress of antigen specific lymphocytes is modulated directly by TLR2 expressed on T cells. To clarify the mechanisms controlling early and late mobilization of T cells we examined the expression of activation markers and adhesion molecules involved in T cell trafficking. We show that early relocation associated with intermediate expression of CD44, a marker of T cell activation as well as adhesion molecule controlling T cell migration under inflammatory conditions. Our results reveal that pathogens engaging TLR2 on activated T cells through a polymorphic site modulate expression of activation/adhesion molecules and regulate effector T cells trafficking in vivo
TLR2 haplotype and M. Tuberculosis in the adjuvant co-modulate trafficking of CNS-specific effector cells
No full textCyclooxygenase-2 (COX-2) inhibition constrains indoleamine 2,3-dioxygenase 1 (IDO1) activity in acute myeloid leukaemia cells
Full text linkIndoleamine 2,3-dioxygenase 1 (IDO1) metabolizes L-tryptophan to kynurenines (KYN), inducing T-cell suppression either directly or by altering antigen-presenting-cell function. Cyclooxygenase (COX)-2, the rate-limiting enzyme in the synthesis of prostaglandins, is over-expressed by several tumours. We aimed at determining whether COX-2 inhibitors down-regulate the IFN-g-induced expression of IDO1 in acute myeloid leukaemia (AML) cells. IFN-γ at 100 ng/mL up-regulated COX-2 and IDO1 in HL-60 AML cells, both at mRNA and protein level. The increased COX-2 and IDO1 expression correlated with heightened production of prostaglandin (PG)E2 and kynurenines, respectively. Nimesulide, a preferential COX-2 inhibitor, down-regulated IDO1 mRNA/protein and attenuated kynurenine synthesis, suggesting that overall IDO inhibition resulted both from reduced IDO1 gene transcription and from inhibited IDO1 catalytic activity. From a functional standpoint, IFN-g-challenged HL-60 cells promoted the in vitro conversion of allogeneic CD4+CD25− T cells into bona fide CD4+CD25+FoxP3+ regulatory T cells, an effect that was significantly reduced by treatment of IFN-γ-activated HL-60 cells with nimesulide. Overall, these data point to COX-2 inhibition as a potential strategy to be pursued with the aim at circumventing leukaemia-induced, IDO-mediated immune dysfunctio
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
Culture of human cell lines by a pathogen-inactivated human platelet lysate
Full text linkAlternatives to the use of fetal bovine serum (FBS) have been investigated to ensure xeno-free growth condition. In this study we evaluated the efficacy of human platelet lysate (PL) as a substitute of FBS for the in vitro culture of some human cell lines. PL was obtained by pools of pathogen inactivated human donor platelet (PLT) concentrates. Human leukemia cell lines (KG-1, K562, JURKAT, HL-60) and epithelial tumor cell lines (HeLa and MCF-7) were cultured with either FBS or PL. Changes in cell proliferation, viability, morphology, surface markers and cell cycle were evaluated for each cell line. Functional characteristics were analysed by drug sensitivity test and cytotoxicity assay. Our results demonstrated that PL can support growth and expansion of all cell lines, although the cells cultured in presence of PL experienced a less massive proliferation compared to those grown with FBS. We found a comparable percentage of viable specific marker-expressing cells in both conditions, confirming lineage fidelity in all cultures. Functionality assays showed that cells in both FBS- and PL-supported cultures maintained their normal responsiveness to adriamycin and NK cell-mediated lysis. Our findings indicate that PL is a feasible serum substitute for supporting growth and propagation of haematopoietic and epithelial cell lines with many advantages from a perspective of process standardization, ethicality and product safety
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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