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- Osipov, V. Yu., et al.
(författare)
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Raman characterization and UV optical absorption studies of surface plasmonresonance in multishell nanographite
- 2011
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Ingår i: Diamond and related materials. - : Elsevier. - 0925-9635 .- 1879-0062. ; 20:2, s. 205-209
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Tidskriftsartikel (refereegranskat)abstract
- Nanographite (NG) particles were produced by annealing of superpurified detonation nanodiamonds (grain size ~ 5 nm) at 1600 °C. The aim of this research was to provide Raman characterization of nanographites obtained and to investigate characteristic features of UV optical absorption in NG suspensions caused by the excitation of surface plasmon resonance (SPR) and its dependence on disorder and defectiveness of graphene shells during their transformation. The 1-st and 2-nd order Raman spectra of the NG samples excited at 514 nm were analyzed. Two different approaches applied for evaluation of the in-plane NG crystallite sizes by using the D- and G-band intensities ratio gave quite different results (~ 3.5 nm and ~ 5.5 nm) reflecting, most likely, a complicated NG structure. The changes in both intensity and position of SPR absorption peak for water suspension of NG particles may originate in structural imperfections and/or changes in aggregation of NG particles.
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| 2. |
- Maguire, Casey A., et al.
(författare)
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Microvesicle-associated AAV Vector as a Novel Gene Delivery System
- 2012
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Ingår i: Molecular Therapy. - New York : Nature Publishing Group. - 1525-0016 .- 1525-0024. ; 20:5, s. 960-971
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Tidskriftsartikel (refereegranskat)abstract
- Adeno-associated virus (AAV) vectors have shown remarkable efficiency for gene delivery to cultured cells and in animal models of human disease. However, limitations to AAV vectored gene transfer exist after intravenous transfer, including off-target gene delivery (e.g., liver) and low transduction of target tissue. Here, we show that during production, a fraction of AAV vectors are associated with microvesicles/exosomes, termed vexosomes (vector-exosomes). AAV capsids associated with the surface and in the interior of microvesicles were visualized using electron microscopy. In cultured cells, vexosomes outperformed conventionally purified AAV vectors in transduction efficiency. We found that purified vexosomes were more resistant to a neutralizing anti-AAV antibody compared to conventionally purified AAV. Finally, we show that vexosomes bound to magnetic beads can be attracted to a magnetized area in cultured cells. Vexosomes represent a unique entity which offers a promising strategy to improve gene delivery.
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| 3. |
- Yeung, M M, et al.
(författare)
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Characterisation of mucosal lymphoid aggregates in ulcerative colitis : immune cell phenotype and TcR-gammadelta expression.
- 2000
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Ingår i: Gut. - 0017-5749 .- 1468-3288. ; 47:2, s. 215-27
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND AIMS: A histopathological feature considered indicative of ulcerative colitis (UC) is the so-called basal lymphoid aggregates. Their relevance in the pathogenesis of UC is, however, unknown. We have performed a comprehensive analysis of the immune cells in these aggregates most likely corresponding to the lymphoid follicular hyperplasia also described in other colitides.METHODS: Resection specimens of UC and normal colon were analysed by immunomorphometry, immunoflow cytometry, and immunoelectron microscopy, using a large panel of monoclonal antibodies.RESULTS: (1) In all cases of UC, colonic lamina propria contained numerous basal aggregates composed of lymphocytes, follicular dendritic cells, and CD80/B7.1 positive dendritic cells. (2) CD4(+)CD28(-) alphabeta T cells and B cells were the dominant cell types in the aggregates. (3) The aggregates contained a large fraction of cells that are normally associated with the epithelium: that is, gammadelta T cells (11 (7)%) and alpha(E)beta(7)(+) cells (26 (13)%). The gammadelta T cells used Vdelta1 and were CD4(-)CD8(-). Immunoelectron microscopy analysis demonstrated TcR-gammadelta internalisation and surface downregulation, indicating that the gammadelta T cells were activated and engaged in the disease process. (4) One third of cells in the aggregates expressed the antiapoptotic protein bcl-2.CONCLUSIONS: Basal lymphoid aggregates in UC colon are a consequence of anomalous lymphoid follicular hyperplasia, characterised by abnormal follicular architecture and unusual cell immunophenotypes. The aggregates increase in size with severity of disease, and contain large numbers of apoptosis resistant cells and activated mucosal gammadelta T cells. The latter probably colonise the aggregates as an immunoregulatory response to stressed lymphocytes or as a substitute for defective T helper cells in B cell activation. gammadelta T cells in the aggregates may be characteristic of UC.
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