149 research outputs found
Fe-substituted mullite powders for the in situ synthesis of carbon nanotubes by catalytic chemical vapor deposition
Powders of iron-substituted mullite were prepared by combustion and further calcination in air at different temperatures. A detailed study involving notably Mo¨ssbauer spectroscopy showed that the Fe3+ ions are distributed between the mullite phase and a corundum phase that progressively dissolves into mullite upon the increase in calcination temperature. Carbon nanotube-Fe-mullite nanocomposites were prepared for the first time by a direct method involving a reduction of these powders in H2-CH4 and without any mechanical mixing step. The carbon nanotubes formed by the catalytic decomposition of CH4 on the smallest metal particles are mostly double-walled and multiwalled, although some carbon nanofibers are also observed
MAGE-A protein and MAGE-A10 gene expressions in liver metastasis in patients with stomach cancer
Tumour samples from 71 patients with stomach cancer, 41 patients with liver metastasis (group A) and 15 patients each in stages II–IV (group B) and stage I (group C) without liver metastasis were analysed. MAGE-A protein expression was evaluated by immunohistochemistry using a 6C1 monoclonal antibody and MAGE-A10 mRNA expression was detected by highly sensitive in situ hybridisation using a cRNA probe. Expressions of MAGE-A protein and MAGE-A10 mRNA in group A were detected in 65.9 and 80.5%, respectively. Both protein and gene showed significantly higher expression in group A than those in groups B (6.7, 26.7%) and C (0, 0%) (P=0.0003, P=<0.0001, respectively). MAGE-A10 mRNA expression in liver metastasis was found in eight (88.9%) out of nine patients. The concordant rate between MAGE-A family protein expression and MAGE-A10 mRNA expression in the primary sites was 81.7% (P<0.0001). MAGE-A10 gene expression was associated with reduced survival duration. The results of this study suggest that MAGE-A10 is a possible target in active immunotherapy for advanced stomach cancer
Clinicopathological and biological significance of mitotic centromere-associated kinesin overexpression in human gastric cancer
Mitotic centromere-associated kinesin (MCAK) is a microtubule (MT) depolymerase necessary for ensuring proper kinetochore MT attachment during spindle formation. To determine MCAK expression status and its clinicopathological significance, real-time reverse transcriptase–polymerase chain reaction was used in 65 cases of gastric cancer. MCAK gene expression in cancer tissue was significantly higher than expression in non-malignant tissue (P<0.05). Elevated MCAK expression was significantly associated with lymphatic invasion (P=0.01) and lymph node metastasis (P=0.04). Furthermore, patients with high MCAK expression had a significantly poorer survival rate than those with low MCAK expression (P=0.008). Immunohistochemical study revealed that expression of MCAK was primarily observed in cancer cells. Additionally, a gastric cancer cell line (AZ521) that stably expressed MCAK was established and used to investigate the biological effects of the MCAK gene. In vitro results showed that cells transfected with MCAK had a high rate of proliferation (P<0.001) and increased migratory ability (P<0.001) compared to mock-transfected cells. This study demonstrated that elevated expression of MCAK may be associated with lymphatic invasion, lymph node metastasis, and poor prognosis. These characteristics may be due in part to the increased proliferative and migratory ability of cells expressing MCAK
Normalization of the Lymph Node T Cell Stromal Microenvironment in lpr/lpr Mice Is Associated with SU5416-Induced Reduction in Autoantibodies
The vascular-stromal elements of lymph nodes can play important roles in regulating the activities of the lymphocytes within. During model immune responses, the vascular-stromal compartment has been shown to undergo proliferative expansion and functional alterations. The state of the vascular-stromal compartment and the potential importance of this compartment in a spontaneous, chronic model of autoimmunity have not been well studied. Here, we characterize the vascular expansion in MRL-lpr/lpr lymph nodes and attempt to ask whether inhibiting this expansion can interfere with autoantibody generation. We show that characteristics of vascular expansion in enlarging MRL-lpr/lpr lymph nodes resemble that of the VEGF-dependent expansion that occurs in wild-type mice after model immunization. Surprisingly, treatment with SU5416, an inhibitor of VEGF and other receptor tyrosine kinases, did not have sustained effects in inhibiting vascular growth, but attenuated the anti-dsDNA response and altered the phenotype of the double negative T cells that are expanded in these mice. In examining for anatomic correlates of these immunologic changes, we found that the double negative T cells are localized within ectopic follicles around a central B cell patch and that these T cell-rich areas lack the T zone stromal protein ER-TR7 as well as other elements of a normal T zone microenvironment. SU5416 treatment disrupted these follicles and normalized the association between T zone microenvironmental elements and T cell-rich areas. Recent studies have shown a regulatory role for T zone stromal elements. Thus, our findings of the association of anti-dsDNA responses, double negative T cell phenotype, and altered lymphocyte microenvironment suggest the possibility that lymphocyte localization in ectopic follicles protects them from regulation by T zone stromal elements and functions to maintain autoimmune responses. Potentially, altering the lymphocyte microenvironment that is set up by the vascular-stromal compartment can be a means by which to control undesired autoimmune responses
BAAV Mediated GJB2 Gene Transfer Restores Gap Junction Coupling in Cochlear Organotypic Cultures from Deaf Cx26Sox10Cre Mice
The deafness locus DFNB1 contains GJB2, the gene encoding connexin26 and GJB6, encoding connexin30, which appear to be coordinately regulated in the inner ear. In this work, we investigated the expression and function of connexin26 and connexin30 from postnatal day 5 to adult age in double transgenic Cx26Sox10Cre mice, which we obtained by crossing connexin26 floxed mice with a deleter Sox10–Cre line. Cx26Sox10Cre mice presented with complete connexin26 ablation in the epithelial gap junction network of the cochlea, whereas connexin30 expression was developmentally delayed; immunolabeling patterns for both connexins were normal in the cochlear lateral wall. In vivo electrophysiological measurements in Cx26Sox10Cre mice revealed profound hearing loss accompanied by reduction of endocochlear potential, and functional experiments performed in postnatal cochlear organotypic cultures showed impaired gap junction coupling. Transduction of these cultures with a bovine adeno associated virus vector restored connexin26 protein expression and rescued gap junction coupling. These results suggest that restoration of normal connexin levels by gene delivery via recombinant adeno associated virus could be a way to rescue hearing function in DFNB1 mouse models and, in future, lead to the development of therapeutic interventions in humans
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