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81.
Nasreen Vohra Monique Verhaegen Lisa Martin Amy Mackay Shari Pilon-Thomas 《Cancer immunology, immunotherapy : CII》2010,59(5):729-736
Due to the pivotal role that dendritic cells (DC) play in eliciting functional anti-tumor T cell responses, immunotherapeutic
approaches utilizing DC-based vaccines have readily been exploited. It has been argued that, in the setting of immunotherapy,
mature DC will be more efficient at T cell priming and, therefore, required for effective vaccination. As TNF-alpha is commonly
used as a DC maturation factor, we have examined the efficacy of treatment with DC matured with TNF-alpha (DC-TNF) in a murine
model of melanoma. We have now shown that treatment with DC-TNF leads to an increase in the number of lung metastases as compared
to mice treated with immature DC. No differences in the number of CD4+CD25+ T-regulatory cells were measured in the lungs of DC-TNF-treated mice. On examination of the infiltrating lymphocytes, an
enhanced secretion of IL-10 and a higher percentage of CD4+IL-10+ T cells were measured in the lungs of DC-TNF-treated mice. However, treatment with DC-TNF did not enhance the number of melanoma
lesions in the lungs of IL-10 knockout mice or in mice depleted of CD4+ T cells. Together, these studies indicate that treatment of melanoma-bearing mice with DC treated with TNF-alpha can induce
IL-10 production by resident cells at the tumor site, leading to immune tolerance and exacerbation of disease. 相似文献
82.
R M Vohra 《Applied and environmental microbiology》1992,58(1):403-404
A simple method that allows easy identification of rifamycin B-producing strains is described. This method involves the use of an enzyme, rifamycin oxidase, which converts inactive rifamycin B to active rifamycin S. In this method, colonies to be tested are grown in pairs. The two colonies are then transferred to two plates seeded with a sensitive strain of Staphylococcus aureus, one plate of which contains the enzyme rifamycin oxidase. All paired colonies which show a larger inhibition zone diameter on the enzyme-containing plate are identified as rifamycin B producers. 相似文献
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Gerdts J Sasaki Y Vohra B Marasa J Milbrandt J 《The Journal of biological chemistry》2011,286(32):28011-28018
Axon degeneration is an active, evolutionarily conserved self-destruction program by which compromised axons fragment in response to varied insults. Unlike programmed cell death, axon degeneration is poorly understood. We have combined robotic liquid handling with automated microscopy and image analysis to create a robust screening platform to measure axon degeneration in mammalian primary neuronal cultures. Using this assay, we performed an unbiased screen of 480 bioactive compounds, identifying 11 that reproducibly delay fragmentation of severed axons in vitro, including two inhibitors of glycogen synthase kinase 3 and two inhibitors of IκB kinase. Knockdown of each of these targets by shRNA lentivirus also delays axon degeneration in vitro, further supporting their role in the axon degeneration program. 相似文献
86.
van der Wel H Johnson JM Xu Y Karunaratne CV Wilson KD Vohra Y Boons GJ Taylor CM Bendiak B West CM 《Biochemistry》2011,50(10):1700-1713
87.
Dictyostelium discoideum, a unicellular eukaryote, exhibits multicellularity upon nutrient starvation and is a good model system for developmental studies, and for the study of various signal transduction pathways. Reactive oxygen species at low doses act as signaling molecules; however, at high doses they are known to cause DNA damage that results in the activation of poly(ADP-ribose) polymerase (PARP). We have earlier reported the high resistance of the unicellular stage of D. discoideum to oxidative stress, and we now show the response of this organism to oxidative stress and the role of PARP during development. We used hydroxylamine (HA) to induce in situ generation of H(2)O(2) and monitored the effect of benzamide, a PARP inhibitor, on oxidative stress-induced changes in D. discoideum development. Interestingly, oxidative stress resulted in PARP activation within 5 min that was inhibited by benzamide. Oxidative stress-induced delay in developmental pattern was also partially restored by benzamide. We studied the long-term effects of PARP inhibition under oxidative stress, and our results demonstrated that spores formed under HA stress exhibited significant delay in germination in comparison to benzamide-pretreated HA-stressed cells. However, second-generation cells showed normal development, signifying that PARP inhibition has no deleterious effect on D. discoideum development under oxidative stress. 相似文献
88.
Nanostructured biocomposite scaffolds based on collagen coelectrospun with nanohydroxyapatite 总被引:3,自引:0,他引:3
Nanofibrous biocomposite scaffolds of type I collagen and nanohydroxyapatite (nanoHA) of varying compositions (wt %) were prepared by electrostatic cospinning. The scaffolds were characterized for structure and morphology by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), atomic force microscopy (AFM) and X-ray diffraction (XRD) techniques. The scaffolds have a porous nanofibrous morphology with random fibers in the range of 500-700 nm diameters, depending on the composition. FT-IR and XRD showed the presence of nanoHA in the fibers. The surface roughness and diameter of the fibers increased with the presence of nanoHA in biocomposite fiber as evident from AFM images. Tensile testing and nanoindendation were used for the mechanical characterization. The pure collagen fibrous matrix (without nanoHA) showed a tensile strength of 1.68 +/- 0.10 MPa and a modulus of 6.21 +/- 0.8 MPa with a strain to failure value of 55 +/- 10%. As the nanoHA content in the randomly oriented collagen nanofibers increased to 10%, the ultimate strength increased to 5 +/- 0.5 MPa and the modulus increased to 230 +/- 30 MPa. The increase in tensile modulus may be attributed to an increase in rigidity over the pure polymer when the hydroxyapatite is added and/or the resulting strong adhesion between the two materials. The vapor phase chemical crosslinking of collagens using glutaraldehyde further increased the mechanical properties as evident from nanoindentation results. A combination of nanofibrous collagen and nanohydroxyapatite that mimics the nanoscale features of the extra cellular matrix could be promising for application as scaffolds for hard tissue regeneration, especially in low or nonload bearing areas. 相似文献
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