JoVE Visualize What is visualize?
Stop Reading. Start Watching.
Advanced Search
Stop Reading. Start Watching.
Regular Search
Find video protocols related to scientific articles indexed in Pubmed.
Designed TALE proteins efficiently induced the expression of latent HIV-1 in latently infected cells.
AIDS Res. Hum. Retroviruses
PUBLISHED: 11-19-2014
Show Abstract
Hide Abstract
HIV latency is the foremost barrier to clearing HIV infection from patients. Reactivation of latent HIV-1 represents a promising strategy to deplete these viral reservoirs. Here, we report a novel approach to reactivate latent HIV-1 provirus using artificially designed transcription activator-like effector (TALE) fusion proteins containing a DNA-binding domain specifically targeting the HIV-1 promoter and the herpes simplex virus-based transcriptional activator VP64 domain. We engineered four TALE genes (TALE1-4) encoding TALE proteins, each specifically targeting different 20-bp DNA sequences within the HIV-1 promoter, and we constructed four TALE-VP64 expression vectors corresponding to TALE1-4. We found that TALE1-VP64 effectively reactivated HIV-1 gene expression in latently infected C11 and A10.6 cells. We further confirmed that TALE1-VP64 reactivated latent HIV-1 via specific binding to the HIV-LTR promoter. Moreover, we also found that TALE1-VP64 did not affect cell proliferation or cell cycle distribution. Taken together, our data demonstrated that TALE1-VP64 can specifically and effectively reactivate latent HIV-1 transcription, suggesting that this strategy may provide a novel approach for anti-HIV-1 latency therapy in the future.
Related JoVE Video
Large acceptance of non-collinear phase-matching second harmonic generation on the surface of an anomalous-like bulk dispersion medium.
Opt Express
PUBLISHED: 11-18-2014
Show Abstract
Hide Abstract
We investigate several bandwidths of non-collinear phase-matching second harmonic generation, which is generated by sum-frequency of the incident and reflected wave on the inner surface of a z-cut 5%/mol MgO : LiNbO3 crystal. The bandwidths of angle, temperature and wavelength in this configuration are measured to be about 0.51°, 4.1°C and 6 nm, respectively. The large acceptance of non-collinear phase-matching second harmonic generated on the surface shows attractive potential in the application of wavelength conversion.
Related JoVE Video
Functionalization of Monolithic and Porous Three-Dimensional Graphene by One-Step Chitosan Electrodeposition for Enzymatic Biosensor.
ACS Appl Mater Interfaces
PUBLISHED: 11-11-2014
Show Abstract
Hide Abstract
Biological modification of monolithic and porous 3D graphene is of great significance for extending its application in fabricating highly sensitive biosensors. The present work reports on the first biofunctionalization of monolithic and freestanding 3D graphene foam for one-step preparation of reagentless enzymatic biosensors by controllable chitosan (CS) electrodeposition technology. Using a homogeneous three-component electrodeposition solution containing a ferrocene (Fc) grafted CS hybrid (Fc-CS), glucose oxidase (GOD), and single-walled carbon nanotubes (SWNTs), a homogeneous biocomposite film of Fc-CS/SWNTs/GOD was immobilized on the surface of 3D graphene foam by one-step electrodeposition. The Fc groups grafted on chitosan can be stably immobilized on the 3D graphene surface and keep their original electrochemical activity. The SWNTs doped into the Fc-CS matrix act as a nanowire to facilitate electron transfer and improve the conductivity of the biocomposite film. Combined with the extraordinary properties of 3D graphene foam including large active surface area, high conductivity, and fast mass transport dynamics, the 3D graphene based enzymatic biosensor achieved a large linear range (5.0 ?M to 19.8 mM), a low detection limit (1.2 ?M), and rapid response (reaching the 95% steady-state response within 8 s) for reagentless detection of glucose in the phosphate buffer solution.
Related JoVE Video
Cherenkov second-harmonic Talbot effect in one-dimension nonlinear photonic crystal.
Opt Lett
PUBLISHED: 11-01-2014
Show Abstract
Hide Abstract
We demonstrate a new method to generate second-harmonic Talbot effect through degenerate Cherenkov radiation in one-dimension anomalous-dispersion-like nonlinear photonic crystals. In anomalous-dispersion-like medium, the degenerated nonlinear Cherenkov radiation can be achieved and is parallel to domain walls, of which the intensity is adjusted by the second-order nonlinear coefficient. In this system the one-dimension nonlinear photonic crystal can be regarded as a nonlinear grating, which is necessary for nonlinear Talbot effect. This is a new method to generate enhanced nonlinear Talbot effect in addition to the quasi-phase-matching technique reported previously.
Related JoVE Video
[Studies on the correlation between the expression of Toll-like receptor 4 and the synovitis of the temporomandibular joint in rats].
Zhonghua Kou Qiang Yi Xue Za Zhi
PUBLISHED: 10-30-2014
Show Abstract
Hide Abstract
To investigate the expression of the Toll-like receptor-4 (TLR-4) in temporo-mandibular joint synovitis in rats, and to discuss the correlation between the expression of TLR-4 and the synovitis.
Related JoVE Video
[Effects of Klotho protein on proliferation, migration, adhesion and vascular endothelial growth factor expression of human umbilical vein cells].
Zhonghua Yi Xue Za Zhi
PUBLISHED: 10-22-2014
Show Abstract
Hide Abstract
To explore the effects of anti-aging Klotho protein in the proliferation, migration and adhesiveness of human umbilical vein endothelial cell (HUVEC) and its influence of vascular endothelial growth factor (VEGF) expression in HUVEC.
Related JoVE Video
A novel two-dimensional preparative chromatography method designed for the separation of traditional animal Tibetan medicine Osteon Myospalacem Baileyi.
J Sep Sci
PUBLISHED: 09-23-2014
Show Abstract
Hide Abstract
Animal medicine is an important part in traditional Tibetan medicine. However, information about the chemical composition of animal medicine is very limited, and there is a lack of comprehensive chromatographic purification methods. In the present work, animal medicine Osteon Myospalacem Baileyi was taken as an example and a novel two-dimensional preparative chromatographic method was established for the preparation of single compounds with high purity from the extract of Osteon Myospalacem Baileyi. The first-dimension preparation was carried on a DAISO Silica prep column, and ten fractions were obtained from the 112.3 g crude sample within 12 injections. A diol prep column used in nonaqueous mobile phase was selected for the second-dimension preparation. The purity of the compounds isolated from the crude extract was >98%, which indicated that the method built in this work was efficient to manufacture single compounds of high purity from the extract of Osteon Myospalacem Baileyi. Additionally, this method showed great potential in the purification of weakly polar chemicals and it could act as a good example in the purification of other traditional animal medicines.
Related JoVE Video
Yersinia Protein Kinase A Phosphorylates Vasodilator-Stimulated Phosphoprotein to Modify the Host Cytoskeleton.
Cell. Microbiol.
PUBLISHED: 09-13-2014
Show Abstract
Hide Abstract
Pathogenic Yersinia species evolved a type III secretion system that injects a set of effectors into the host cell cytosol to promote infection. One of these effectors, Yersinia protein kinase A (YpkA), is a multidomain effector that harbors a Ser/Thr kinase domain and a guanine dissociation inhibitor (GDI) domain. The intercellular targets of the kinase and GDI domains of YpkA were identified to be G?q and the small GTPases RhoA and Rac1, respectively, which synergistically induce cytotoxic effects on infected cells. In this study, we demonstrate that vasodilator-stimulated phosphoprotein (VASP), which is critical for regulation of actin assembly, cell adhesion, and motility is a direct substrate of YpkA kinase activity. Ectopic coexpression of YpkA and VASP in HEK293T cells lead to the phosphorylation of VASP at S157, and YpkA kinase activity is essential for VASP phosphorylation at this site. Moreover, YpkA directly phosphorylates VASP in in vitro kinase assay. YpkA-mediated VASP phosphorylation significantly inhibits actin polymerization and promotes the disruption of actin cytoskeleton, which inhibits the phagocytosis. Taken together, our study found a novel molecular mechanism used by YpkA to disrupt cytoskeleton dynamics, thereby promoting the anti-phagocytosis ability of pathogenic Yersiniae.
Related JoVE Video
Secreted clusterin (sCLU) regulates cell proliferation and chemosensitivity to cisplatin by modulating ERK1/2 signals in human osteosarcoma cells.
World J Surg Oncol
PUBLISHED: 08-09-2014
Show Abstract
Hide Abstract
Several studies have shown that secreted clusterin (sCLU) up-regulation in multi-drug resistant osteosarcoma (OS) cells relates to enhanced drug resistance. Furthermore, sCLU silencing directed against sCLU induces significant reduction of cellular growth and sensitizes OS cells to chemotherapy. However, the molecular mechanisms underlying the effect of sCLU on OS cells are not known.
Related JoVE Video
Advances in self-assembled chitosan nanomaterials for drug delivery.
Biotechnol. Adv.
PUBLISHED: 08-07-2014
Show Abstract
Hide Abstract
Nanomaterials based on chitosan have emerged as promising carriers of therapeutic agents for drug delivery due to good biocompatibility, biodegradability, and low toxicity. Chitosan originated nanocarriers have been prepared by mini-emulsion, chemical or ionic gelation, coacervation/precipitation, and spray-drying methods. As alternatives to these traditional fabrication methods, self-assembled chitosan nanomaterials show significant advantages and have received growing scientific attention in recent years. Self-assembly is a spontaneous process by which organized structures with particular functions and properties could be obtained without additional complicated processing or modification steps. In this review, we focus on recent progress in the design, fabrication and physicochemical aspects of chitosan-based self-assembled nanomaterials. Their applications in drug delivery of different therapeutic agents are also discussed in details.
Related JoVE Video
Early detection of atrophy of foot muscles in Chinese patients of type 2 diabetes mellitus by high-frequency ultrasonography.
J Diabetes Res
PUBLISHED: 08-06-2014
Show Abstract
Hide Abstract
The aim of this study was to evaluate the diagnostic value of high-frequency ultrasonography in detecting atrophy of foot muscles in Chinese patients of type 2 diabetes mellitus (T2DM). Chinese patients of T2DM with (n = 56) or without (n = 50) diabetic peripheral neuropathy (DPN) and the control subjects (n = 50) were enrolled. The nondominant foot of all subjects was examined with high-frequency ultrasonography. The transverse diameter, thickness, and cross-sectional area of the extensor digitorum brevis muscle (EDB) and the thickness of the muscles of the first interstitium (MILs) were measured. The results showed that the ultrasonographic transverse diameter, thickness, and cross-sectional area of EDB and the thickness of MILs in patients of T2DM with DPN were significantly smaller than those in patients of T2DM without DPN (all P < 0.01) and those in the control subjects (all P < 0.01). The transverse diameter and cross-sectional area of the EDB and thickness of MILs in patients of T2DM without DPN were significantly smaller than those of the control subjects (all P < 0.01). In conclusion, the atrophy of foot muscle in Chinese T2DM patients can be detected by high-frequency ultrasonography. Notably, ultrasonography may detect early atrophy of foot muscles in patients without DPN.
Related JoVE Video
The BCL2L1 and PGAM5 axis defines hypoxia-induced receptor-mediated mitophagy.
Autophagy
PUBLISHED: 07-17-2014
Show Abstract
Hide Abstract
Receptor-mediated mitophagy is one of the major mechanisms of mitochondrial quality control essential for cell survival. We previously have identified FUNDC1 as a mitophagy receptor for selectively removing damaged mitochondria in mammalian systems. A critical unanswered question is how receptor-mediated mitophagy is regulated in response to cellular and environmental cues. Here, we report the striking finding that BCL2L1/Bcl-xL, but not BCL2, suppresses mitophagy mediated by FUNDC1 through its BH3 domain. Mechanistically, we demonstrate that BCL2L1, but not BCL2, interacts with and inhibits PGAM5, a mitochondrially localized phosphatase, to prevent the dephosphorylation of FUNDC1 at serine 13 (Ser13), which activates hypoxia-induced mitophagy. Our results showed that the BCL2L1-PGAM5-FUNDC1 axis is critical for receptor-mediated mitophagy in response to hypoxia and that BCL2L1 possesses unique functions distinct from BCL2.
Related JoVE Video
Zinc finger nuclease: a new approach for excising HIV-1 proviral DNA from infected human T cells.
Mol. Biol. Rep.
PUBLISHED: 06-12-2014
Show Abstract
Hide Abstract
A major reason that Acquired Immune Deficiency Syndrome (AIDS) cannot be completely cured is the human immunodeficiency virus 1 (HIV-1) provirus integrated into the human genome. Though existing therapies can inhibit replication of HIV-1, they cannot eradicate it. A molecular therapy gains popularity due to its specifically targeting to HIV-1 infected cells and effectively removing the HIV-1, regardless of viral genes being active or dormant. Now, we propose a new method which can excellently delete the HIV provirus from the infected human T cell genome. First, we designed zinc-finger nucleases (ZFNs) that target a sequence within the long terminal repeat (LTR) U3 region that is highly conserved in whole clade. Then, we screened out one pair of ZFN and named it as ZFN-U3. We discovered that ZFN-U3 can exactly target and eliminate the full-length HIV-1 proviral DNA after the infected human cell lines treated with it, and the frequency of its excision was about 30 % without cytotoxicity. These results prove that ZFN-U3 can efficiently excise integrated HIV-1 from the human genome in infected cells. This method to delete full length HIV-1 in human genome can therefore provide a novel approach to cure HIV-infected individuals in the future.
Related JoVE Video
Downregulation of cellular c-Jun N-terminal protein kinase and NF-?B activation by berberine may result in inhibition of herpes simplex virus replication.
Antimicrob. Agents Chemother.
PUBLISHED: 06-09-2014
Show Abstract
Hide Abstract
Berberine is a quaternary ammonium salt from the protoberberine group of isoquinoline alkaloids. Some reports show that berberine exhibits anti-inflammatory, antitumor, and antiviral properties by modulating multiple cellular signaling pathways, including p53, nuclear factor ?B (NF-?B), and mitogen-activated protein kinase. In the present study, we investigated the antiviral effect of berberine against herpes simplex virus (HSV) infection. Current antiherpes medicines such as acyclovir can lessen the recurring activation when used early at infection but are unable to prevent or cure infections where treatment has selected for resistant mutants. In searching for new antiviral agents against herpesvirus infection, we found that berberine reduced viral RNA transcription, protein synthesis, and virus titers in a dose-dependent manner. To elucidate the mechanism of its antiviral activity, the effect of berberine on the individual steps of viral replication cycle of HSV was investigated via time-of-drug addition assay. We found that berberine acted at the early stage of HSV replication cycle, between viral attachment/entry and genomic DNA replication, probably at the immediate-early gene expression stage. We further demonstrated that berberine significantly reduced HSV-induced NF-?B activation, as well as I?B-? degradation and p65 nuclear translocation. Moreover, we found that berberine also depressed HSV-induced c-Jun N-terminal kinase (JNK) phosphorylation but had little effect on p38 phosphorylation. Our results suggest that the berberine inhibition of HSV infection may be mediated through modulating cellular JNK and NF-?B pathways.
Related JoVE Video
Highly dispersed SrTiO? nanocubes from a rapid sol-precipitation method.
Nanoscale
PUBLISHED: 06-06-2014
Show Abstract
Hide Abstract
SrTiO? nanocubes and their hyperstable nanocrystalline sols were synthesized by a rapid sol-precipitation method under atmospheric pressure. Using triethylene glycol (TEG) to control the hydrolysis rate of tetrabutyl titanate, the SrTiO? nanocrystalline sol was obtained in as little time as 2 h. The formation kinetics of the SrTiO? nanocubes indicated that controlled hydrolysis is critical to the generation of a well defined cubic shape. The Fourier transform infrared (FT-IR) spectrum confirms the existence of TEG molecules on the surface of the particles and explains the high dispersion of the nanocubes in polar solvents. Owing to the large specific surface area (99.065 m(2) g(-1)), cubic SrTiO? nanocrystals showed enhanced photocatalytic activity. A high-quality SrTiO? nanocrystal film was prepared by spin-coating of the hyperstable sol at 100-160 °C, providing a new low-temperature route for the fabrication of perovskite thin films.
Related JoVE Video
Characterisation of a chitinase from Pseudoalteromonas sp. DL-6, a marine psychrophilic bacterium.
Int. J. Biol. Macromol.
PUBLISHED: 05-27-2014
Show Abstract
Hide Abstract
In this study, we isolated a new psychrophilic bacterium, Pseudoalteromonas sp. DL-6 from marine sediments, which grew well on chitin-containing plates at 4°C. One endo-type chitinase gene, chiA, was cloned from the genomic DNA of this bacterium and heterologously expressed in Escherichia coli BL21 (DE3). ChiA showed very high catalytic activity, even at 4°C, and exhibited maximal activity on a chitinous substrate at pH 8.0 and 20°C. Kinetic studies indicated that ChiA has a greater catalytic efficiency on 4-methylumbelliferyl-?-D-N,N',N?-triacetylchitotriose[4-MU(GlcNAc)3] than on 4-methylumbelliferyl-?-D-N,N'-diacetylchitobioside[4-MU(GlcNAc)2]. Electrospray ionisation mass spectrometry (ESI-MS) analysis showed that the hydrolysis products of powdered chitin after ChiA digestion consisted of a series of chitin oligomers with different degrees of polymerisation. The ChiA mode of action was also examined using (GlcNAc)2-6 as a substrate, and the results suggested that ChiA is a non-processive endo-type chitinase.
Related JoVE Video
A versatile complementation assay for cell-to-cell and long distance movements by cucumber mosaic virus based agro-infiltration.
Virus Res.
PUBLISHED: 05-26-2014
Show Abstract
Hide Abstract
Microinjection, bombardment or tobamovirus and potexvirus based assay has been developed to identify the putative movement protein (MP) or to characterize plasmodesma-mediated macromolecular transport. In this study, we developed a versatile complementation assay for the cell-to-cell and long distance movements of macromolecules by agro-infiltration based on the infectious clones of cucumber mosaic virus (CMV). The movement-deficient CMV reporter was constructed by replacing the MP on RNA 3 with ER targeted GFP. The ectopic expression of CMV MP was able to efficiently move the RNA3-MP::erGFP reporter from the original cell to neighboring cells, whereas CMV MP-M5 mutant was unable to initiate the movement. Importantly, the presence of CMV RNA1 and RNA2 can dramatically amplify the movement signals once the RNA3-MP::erGFP reporter moves out of the original cell. The appropriate observation time for this movement complementation assay was at 48-72 hours post infiltration (hpi), whereas the optimal incubation temperature was between 25 and 28 °C. The ectopic co-expression of MPs from other virus genera, NSm from tomato spotted wilt tospovirus (TSWV) or NSvc4 from rice stripe tenuivirus (RSV), could also facilitate the movement of the RNA3::erGFP reporter from the original cell into other cells. The chimeric mutant virus created by substituting the MP of CMV RNA3 with NSm from TSWV or NSvc4 from RSV move systemically in Nicotiana benthamiana plants by agro-infiltration. This agro-infiltration complementation assay is simple, efficient and reliable. Our approach provides an alternative and powerful tool with great potentials in identifying putative movement protein and characterizing macromolecular trafficking.
Related JoVE Video
Oxaliplatin antagonizes HIV-1 latency by activating NF-?B without causing global T cell activation.
Biochem. Biophys. Res. Commun.
PUBLISHED: 05-13-2014
Show Abstract
Hide Abstract
Reactivation of latent HIV-1 is a promising strategy for the clearance of the viral reservoirs. Because of the limitations of current agents, identification of new latency activators is urgently required. Using an established model of HIV-1 latency, we examined the effect of Oxaliplatin on latent HIV-1 reactivation. We showed that Oxaliplatin, alone or in combination with valproic acid (VPA), was able to reactivate HIV-1 without inducing global T cell activation. We also provided evidence that Oxaliplatin reactivated HIV-1 expression by inducing nuclear factor kappa B (NF-?B) nuclear translocation. Our results indicated that Oxaliplatin could be a potential drug candidate for anti-latency therapies.
Related JoVE Video
Single-cell RNA-seq reveals dynamic paracrine control of cellular variation.
Nature
PUBLISHED: 05-02-2014
Show Abstract
Hide Abstract
High-throughput single-cell transcriptomics offers an unbiased approach for understanding the extent, basis and function of gene expression variation between seemingly identical cells. Here we sequence single-cell RNA-seq libraries prepared from over 1,700 primary mouse bone-marrow-derived dendritic cells spanning several experimental conditions. We find substantial variation between identically stimulated dendritic cells, in both the fraction of cells detectably expressing a given messenger RNA and the transcript's level within expressing cells. Distinct gene modules are characterized by different temporal heterogeneity profiles. In particular, a 'core' module of antiviral genes is expressed very early by a few 'precocious' cells in response to uniform stimulation with a pathogenic component, but is later activated in all cells. By stimulating cells individually in sealed microfluidic chambers, analysing dendritic cells from knockout mice, and modulating secretion and extracellular signalling, we show that this response is coordinated by interferon-mediated paracrine signalling from these precocious cells. Notably, preventing cell-to-cell communication also substantially reduces variability between cells in the expression of an early-induced 'peaked' inflammatory module, suggesting that paracrine signalling additionally represses part of the inflammatory program. Our study highlights the importance of cell-to-cell communication in controlling cellular heterogeneity and reveals general strategies that multicellular populations can use to establish complex dynamic responses.
Related JoVE Video
Overall functional gene diversity of microbial communities in three full-scale activated sludge bioreactors.
Appl. Microbiol. Biotechnol.
PUBLISHED: 04-26-2014
Show Abstract
Hide Abstract
Understanding microbial community composition is thought to be crucial for improving process functioning and stabilities of full-scale activated sludge reactors in wastewater treatment plants (WWTPs). However, functional gene compositions of microbial communities within them have not been clearly elucidated. To gain a complete picture of microbial community, in this study, GeoChip 4.2 was used to profile the overall functional genes of three full-scale activated sludge bioreactors, the 16S rRNA gene diversities of which had been unveiled by 454-pyrosequencing in our previous investigation. Triplicate activated sludge samples from each system were analyzed, with the detection of 38,507 to 40,654 functional genes. A high similarity of 77.3-81.2 % shared functional genes was noted among the nine samples, verified by the high 16S rRNA gene similarity with shared operational taxonomic units (OTUs) constituting 66.4-70.0 % of the detected sequences in each system. Correlation analyses showed that the abundances of a wide array of functional genes were associated with system performances. For example, the abundances of carbon degradation genes were strongly correlated to chemical oxygen demand (COD) removal efficiencies (r?=?0.8697, P?
Related JoVE Video
The TLR9 ligand, CpG-ODN, induces protection against cerebral ischemia/reperfusion injury via activation of PI3K/Akt signaling.
J Am Heart Assoc
PUBLISHED: 04-12-2014
Show Abstract
Hide Abstract
Toll-like receptors (TLRs) have been shown to be involved in cerebral ischemia/reperfusion (I/R) injury. TLR9 is located in intracellular compartments and recognizes CpG-DNA. This study examined the effect of CpG-ODN on cerebral I/R injury.
Related JoVE Video
Dilazep synergistically reactivates latent HIV-1 in latently infected cells.
Mol. Biol. Rep.
PUBLISHED: 04-07-2014
Show Abstract
Hide Abstract
The long-lived latently infected cells persist in spite of prolonged highly active anti-retroviral therapy and present a major barrier to a cure of human immunodeficiency virus type 1 (HIV-1) infection. Elimination of this reservoir requires reactivation of the latent virus. None of the current agents can safely and effectively reactivate latent HIV-1 reservoirs. Dilazep, a nucleoside transport inhibitor, is used to treat ischemic dysfunction. However, little is known about the effect of dilazep in inducing HIV expression in latently infected cells. Using the Jurkat T cell model of HIV-1 latency, we found that dilazep effectively reactivates latent HIV-1 gene expression in a dose manner. We observed that dilazep synergistically reactivated latent HIV-1 transcription with valproic acid. We also found that dilazep activates viral latency without inducing cell surface activation markers CD25 and CD69 activation. In summary, dilazep, alone or in combination with VPA, could be useful in future eradication strategies.
Related JoVE Video
Fluorescent nanomicelles for selective detection of Sudan dye in Pluronic F127 aqueous media.
ACS Appl Mater Interfaces
PUBLISHED: 03-26-2014
Show Abstract
Hide Abstract
Novel self-assembled water-soluble nanomicelles that contain fluorescent conjugated polymers (poly(9,9-dioctylfluorene) (PFO) or poly[2,7-(9,9-dihexylfluorene)-alt-4,4'-phenylether] (PF-PE)) have been obtained and used as the highly sensitive/selective platform for Sudan dye detection. The Fluorescent nanomicelles exhibited a highly selective fluorescence quenching by the prohibited food additive Sudan I, while not for the natural pigments: Capsanthin and Beta-carotene, due to the more suitable matching of the LUMOs (lowest unoccupied molecular orbital) of the conjugated polymers with that of Sudan I molecules. The Stern-Volmer constants (K(SV)) of PF-PE/F127 and PFO/F127 for Sudan I were 1,040,480 and 665,000 M(-1), respectively, which were more than 100 times higher than those of the same conjugated polymers in the orgainc solvents. The significantly enhanced sensitivity was due to the collective effect of the F127 micelles to both chromophore and analyte, through which the fluorophone-analyte binding interaction is significantly strengthened and efficient photoinduced charge transfer occurs. The as-proposed materials and approach may be potentially applied in the real-time food safety screening.
Related JoVE Video
Low-dose decitabine-based chemoimmunotherapy for patients with refractory advanced solid tumors: a phase I/II report.
J Immunol Res
PUBLISHED: 03-21-2014
Show Abstract
Hide Abstract
Aberrant DNA methylation is one of the main drivers of tumor initiation and progression. The reversibility of methylation modulation makes it an attractive target for novel anticancer therapies. Clinical studies have demonstrated that high-dose decitabine, a hypomethylating agent, results in some clinical benefits in patients with refractory advanced tumors; however, they are extremely toxic. Low doses of decitabine minimize toxicity while potentially improving the targeted effects of DNA hypomethylation. Based on these mechanisms, low-dose decitabine combined with chemoimmunotherapy may be a new treatment option for patients with refractory advanced tumors. We proposed the regimen of low-dose decitabine-based chemoimmunotherapy for patients with refractory advanced solid tumors. A favorable adverse event profile was observed in our trial that was highlighted by the finding that most of these adverse events were grades 1-2. Besides, the activity of our cohort was optimistic and the clinical benefit rate was up to 60%, and the median PFS was prolonged compared with PFS to previous treatment. We also identified a significant correlation between the PFS to previous treatment and clinical response. The low-dose DAC decitabine-based chemoimmunotherapy might be a promising protocol for improving the specificity and efficiency of patients with refractory advanced solid tumors. This trial is registered in the ClinicalTrials.gov database (identifier NCT01799083).
Related JoVE Video
Norcantharidin enhances ABT-263-mediated anticancer activity in neuroblastoma cells by upregulation of Noxa.
Oncol. Rep.
PUBLISHED: 03-17-2014
Show Abstract
Hide Abstract
Neuroblastoma is an aggressive childhood disease. Even with intensive conventional treatments, the long term survival rate for children with neuroblastoma remains less than 40%, highlighting the importance of finding new therapies. Bcl-2 family proteins play crucial roles in survival, proliferation and chemotherapeutic resistance of neuroblastoma cells. Therefore, targeting Bcl-2 with small molecule inhibitor ABT-263 could be a novel strategy for treatment of neuroblastoma. However, previous studies indicated that most neuroblastoma cell lines are resistant to ABT-263-mediated apoptosis. Thus, it is crucial to discover approaches that could overcome ABT-263 resistance. In this study, we examined the anticancer activity of ABT-263 in combination with norcantharidin (NCTD), a small-molecule anticancer drug derived from a traditional Chinese medicine, in human malignant neuroblastoma cells. We found that NCTD substantially enhanced ABT-263-mediated apoptosis induction, cell viability inhibition, and clonal formation inhibition in neuroblastoma SH-SY5Y and CHLA-119 cell lines. Moreover, the combination anticancer activity was accompanied by upregulation of Noxa, and was associated with characteristics of mitochondrial apoptosis signaling, such as cytosolic release of cytochrome c, activation of caspase-9,-3, and cleavage of PARP. Notably, we observed that knockdown of Noxa significantly attenuated cell death induction by cotreatment with ABT-263 and NCTD, indicating Noxa essentially contributes to the combination anticancer effect. Collectively, our study demonstrated that NCTD could overcome ABT-263-resistance in neuroblastoma cells, and suggested that combinational treatment of ABT-263 with NCTD might be a novel therapeutic option for children with neuroblastoma.
Related JoVE Video
Double-negative feedback loop between ZEB2 and miR-145 regulates epithelial-mesenchymal transition and stem cell properties in prostate cancer cells.
Cell Tissue Res.
PUBLISHED: 03-12-2014
Show Abstract
Hide Abstract
The invasion and metastasis of tumors are triggered by an epithelial to mesenchymal transition (EMT), which is regulated by microRNAs (miRNAs). EMT also promotes malignant tumor progression and the maintenance of the stem cell property, which endows cancer cells with the capabilities of self-renewal and immortalized proliferation. The transcriptional repressor zinc-finger E-box binding homeobox 2 (ZEB2), as an EMT activator, might be an important promoter of metastasis in some tumors. Here, we report that ZEB2 directly represses the transcription of miR-145, which is a strong repressor of EMT. In turn, ZEB2 is also a direct target of miR-145. Further, our findings show that the downregulation of ZEB2 not only represses invasion, migration, EMT, and the stemness of prostate cancer (PCa) cells, but also suppresses the capability of PC-3 cells to invade bone in vivo. Importantly, the expression level of ZEB2 as revealed by immunohistochemical analysis is positively correlated to bone metastasis, the serum free PSA level, the total PSA level, and the Gleason score in PCa patients and is negatively correlated with miR-145 expression in primary PCa specimens. Thus, our findings demonstrate a double-negative feedback loop between ZEB2 and miR-145 and indicate that the ZEB2/miR-145 double-negative feedback loop plays a significant role in the control of EMT and stem cell properties during the bone metastasis of PCa cells. These results suggest that the double-negative feedback loop between ZEB2 and miR-145 contributes to PCa progression and metastasis and might have therapeutic relevance for the bone metastasis of PCa.
Related JoVE Video
Activation of JNK1/2 and p38 MAPK signaling pathways promotes enterovirus 71 infection in immature dendritic cells.
BMC Microbiol.
PUBLISHED: 03-07-2014
Show Abstract
Hide Abstract
c-Jun NH2-terminal kinase/stress-activated kinase (JNK/SAPK) and the p38 mitogen-activated protein kinase (p38 MAPK) are important components of cellular signal transduction pathways, which have been reported to be involved in viral replication. However, little is known about JNK1/2 and p38 MAPK signaling pathways in enterovirus 71 (EV71)-infected immature dendritic cells (iDCs). Thus, iDCs were induced from peripheral blood mononuclear cells (PBMC) and performed to explore the expressions and phosphorylation of molecules in the two signaling pathways as well as secretions of inflammatory cytokines and interferons during EV71 replication.
Related JoVE Video
Th17 cells play a critical role in the development of experimental Sjogren's syndrome.
Ann. Rheum. Dis.
PUBLISHED: 02-28-2014
Show Abstract
Hide Abstract
Although Th17 cells have been increasingly recognised as an important effector in various autoimmune diseases, their function in the pathogenesis of Sjögren's syndrome (SS) remains largely uncharacterised. This study aims to determine the role of Th17 cells in the development of experimental SS (ESS).
Related JoVE Video
MicroRNA-125b protects against myocardial ischaemia/reperfusion injury via targeting p53-mediated apoptotic signalling and TRAF6.
Cardiovasc. Res.
PUBLISHED: 02-27-2014
Show Abstract
Hide Abstract
The present study examined the role of microRNA-125b (miR-125b) in myocardial ischaemia/reperfusion (I/R) injury. We constructed lentivirus-expressing miR-125b (LmiR-125b) and developed transgenic mice with overexpression of miR-125b.
Related JoVE Video
Asymmetric syntheses and bio-evaluation of novel chiral esters derived from substituted tetrafluorobenzyl alcohol.
Bioorg. Med. Chem. Lett.
PUBLISHED: 02-18-2014
Show Abstract
Hide Abstract
A series of novel chiral esters derived from tetrafluorobenzyl alcohol were designed and prepared via asymmetric synthesis. The target molecules have been identified on the basis of analytical spectra data. All newly synthesized compounds have been screened their potential insecticidal activity against Plutella xylostella compared with those of fenvalerate and d-trans-phenothrin by standard method, and the respective pairs of enantiomers (3-B1-R/S, 3-C1-R/S, 3-D1-R/S) indicated significantly different activities.
Related JoVE Video
A regulatory signaling loop comprising the PGAM5 phosphatase and CK2 controls receptor-mediated mitophagy.
Mol. Cell
PUBLISHED: 02-14-2014
Show Abstract
Hide Abstract
Mitochondrial autophagy, or mitophagy, is a major mechanism involved in mitochondrial quality control via selectively removing damaged or unwanted mitochondria. Interactions between LC3 and mitophagy receptors such as FUNDC1, which harbors an LC3-interacting region (LIR), are essential for this selective process. However, how mitochondrial stresses are sensed to activate receptor-mediated mitophagy remains poorly defined. Here, we identify that the mitochondrially localized PGAM5 phosphatase interacts with and dephosphorylates FUNDC1 at serine 13 (Ser-13) upon hypoxia or carbonylcyanide p-trifluoromethoxyphenylhydrazone (FCCP) treatment. Dephosphorylation of FUNDC1 catalyzed by PGAM5 enhances its interaction with LC3, which is abrogated following knockdown of PGAM5 or the introduction of a cell-permeable unphosphorylated peptide encompassing the Ser-13 and LIR of FUNDC1. We further observed that CK2 phosphorylates FUNDC1 to reverse the effect of PGAM5 in mitophagy activation. Our results reveal a mechanistic signaling pathway linking mitochondria-damaging signals to the dephosphorylation of FUNDC1 by PGAM5, which ultimately induces mitophagy.
Related JoVE Video
Mitochondrial DNA and functional investigations into the radiosensitivity of four mouse strains.
Int J Cell Biol
PUBLISHED: 02-12-2014
Show Abstract
Hide Abstract
We investigated whether genetic radiosensitivity-related changes in mtDNA/nDNA ratios are significant to mitochondrial function and if a material effect on mtDNA content and function exists. BALB/c (radiosensitive), C57BL/6 (radioresistant), and F1 hybrid mouse strains were exposed to total body irradiation. Hepatic genomic DNA was extracted, and mitochondria were isolated. Mitochondrial oxygen consumption, ROS, and calcium-induced mitochondrial swelling were measured. Radiation influenced strain-specific survival in vivo. F1 hybrid survival was influenced by maternal input. Changes in mitochondrial content corresponded to survival in vivo among the 4 strains. Calcium-induced mitochondrial swelling was strain dependent. Isolated mitochondria from BALB/c mice were significantly more sensitive to calcium overload than mitochondria from C57BL/6 mice. Maternal input partially influenced the recovery effect of radiation on calcium-induced mitochondrial swelling in F1 hybrids; the hybrid with a radiosensitive maternal lineage exhibited a lower rate of recovery. Hybrids had a survival rate that was biased toward maternal input. mtDNA content and mitochondrial permeability transition pores (MPTP) measured in these strains before irradiation reflected a dominant input from the parent. After irradiation, the MPTP opened sooner in radiosensitive and hybrid strains, likely triggering intrinsic apoptotic pathways. These findings have important implications for translation into predictors of radiation sensitivity/resistance.
Related JoVE Video
A small natural molecule promotes mitochondrial fusion through inhibition of the deubiquitinase USP30.
Cell Res.
PUBLISHED: 02-11-2014
Show Abstract
Hide Abstract
Mitochondrial fusion is a highly coordinated process that mixes and unifies the mitochondrial compartment for normal mitochondrial functions and mitochondrial DNA inheritance. Dysregulated mitochondrial fusion causes mitochondrial fragmentation, abnormal mitochondrial physiology and inheritance, and has been causally linked with a number of neuronal diseases. Here, we identified a diterpenoid derivative 15-oxospiramilactone (S3) that potently induced mitochondrial fusion to restore the mitochondrial network and oxidative respiration in cells that are deficient in either Mfn1 or Mfn2. A mitochondria-localized deubiquitinase USP30 is a target of S3. The inhibition of USP30 by S3 leads to an increase of non-degradative ubiquitination of Mfn1/2, which enhances Mfn1 and Mfn2 activity and promotes mitochondrial fusion. Thus, through the use of an inhibitor of USP30, our study uncovers an unconventional function of non-degradative ubiquitination of Mfns in promoting mitochondrial fusion.
Related JoVE Video
ABRO1 suppresses tumourigenesis and regulates the DNA damage response by stabilizing p53.
Nat Commun
PUBLISHED: 02-04-2014
Show Abstract
Hide Abstract
Abraxas brother 1 (ABRO1) has been reported to be a component of the BRISC complex, a multiprotein complex that specifically cleaves 'Lys-63'-linked ubiquitin. However, current knowledge of the functions of ABRO1 is limited. Here we report that ABRO1 is frequently downregulated in human liver, kidney, breast and thyroid gland tumour tissues. Depletion of ABRO1 in cancer cells reduces p53 levels and enhances clone formation and cellular transformation. Conversely, overexpression of ABRO1 suppresses cell proliferation and tumour formation in a p53-dependent manner. We further show that ABRO1 stabilizes p53 by facilitating the interaction of p53 with USP7. DNA-damage induced accumulation of endogenous ABRO1 as well as translocation of ABRO1 to the nucleus, and the induction of p53 by DNA damage is almost completely attenuated by ABRO1 depletion. Our study shows that ABRO1 is a novel p53 regulator that plays an important role in tumour suppression and the DNA damage response.
Related JoVE Video
Low-coverage single-cell mRNA sequencing reveals cellular heterogeneity and activated signaling pathways in developing cerebral cortex.
Nat. Biotechnol.
PUBLISHED: 01-30-2014
Show Abstract
Hide Abstract
Large-scale surveys of single-cell gene expression have the potential to reveal rare cell populations and lineage relationships but require efficient methods for cell capture and mRNA sequencing. Although cellular barcoding strategies allow parallel sequencing of single cells at ultra-low depths, the limitations of shallow sequencing have not been investigated directly. By capturing 301 single cells from 11 populations using microfluidics and analyzing single-cell transcriptomes across downsampled sequencing depths, we demonstrate that shallow single-cell mRNA sequencing (?50,000 reads per cell) is sufficient for unbiased cell-type classification and biomarker identification. In the developing cortex, we identify diverse cell types, including multiple progenitor and neuronal subtypes, and we identify EGR1 and FOS as previously unreported candidate targets of Notch signaling in human but not mouse radial glia. Our strategy establishes an efficient method for unbiased analysis and comparison of cell populations from heterogeneous tissue by microfluidic single-cell capture and low-coverage sequencing of many cells.
Related JoVE Video
Simultaneous characterisation of fifty coumarins from the roots of Angelica dahurica by off-line two-dimensional high-performance liquid chromatography coupled with electrospray ionisation tandem mass spectrometry.
Phytochem Anal
PUBLISHED: 01-30-2014
Show Abstract
Hide Abstract
The root of Angelica dahurica is a traditional Chinese medicine that used for the treatment of headache, toothache, abscess, furunculosis and acne. Coumarins were the major bioactive constituents of A. dahurica, hence it is worthwhile developing a method to simultaneously characterise them, especially those in trace amounts.
Related JoVE Video
ICU-Onset Clostridium difficile Infection in a University Hospital in China: A Prospective Cohort Study.
PLoS ONE
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
A prospective study was conducted to investigate the incidence, clinical profiles and outcome of ICU-onset CDI in a 50-bed medical ICU at a university hospital in China. Stools were collected from patients who developed ICU-onset diarrhea and was screened for tcdA (toxin A gene) and tcdB (toxin B gene) by PCR. CDI cases were compared with the ICU-onset non-CDI diarrhea cases for demographics, comorbidities, potential risk factors, major laboratory findings and outcomes. Stool samples from CDI cases were subjected to C. difficile culture and C. difficile isolates were screened for tcdA, tcdB and the binary toxin genes (cdtA and cdtB) using multiplex PCR. Strain typing of toxigenic C. difficile isolates was performed using multilocus sequence typing. There were 1,277 patients in the ICU during the study period and 124 (9.7%) developed ICU-onset diarrhea, of which 31 patients had CDI. The incidence of ICU-onset CDI was 25.2 cases per 10,000 ICU days. ICU-onset CDI cases had similar features with ICU-onset non-CDI diarrhea cases including the use of proton pump inhibitors and antibacterial agents. The crude mortality rate of ICU-onset CDI was 22.6%, but the attributable mortality rate of ICU-onset CDI was only 3.2% here. Toxigenic C. difficile isolates were recovered from 28 out of the 31 patients with CDI. cdtA and cdtB were found in two strains. Seventeen STs including 11 new STs were identified. All of the 11 new STs were single-locus variants of known STs and the 17 STs identified here could be clustered into 3 clades. The incidence of ICU-onset CDI here is similar to those in Europe and North America, suggesting that CDI is likely to be a common problem in China. Toxigenic C. difficile here belonged to a variety of STs, which may represent a significant clonal expansion rather than the true clonal diversity.
Related JoVE Video
Impacts of multiwalled carbon nanotubes on nutrient removal from wastewater and bacterial community structure in activated sludge.
PLoS ONE
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
The increasing use of multiwalled carbon nanotubes (MWCNTs) will inevitably lead to the exposure of wastewater treatment facilities. However, knowledge of the impacts of MWCNTs on wastewater nutrient removal and bacterial community structure in the activated sludge process is sparse.
Related JoVE Video
Safety and efficacy of biodegradable drug-eluting vs. bare metal stents: a meta-analysis from randomized trials.
PLoS ONE
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
Biodegradable polymeric coatings have been proposed as a promising strategy to enhance biocompatibility and improve the delayed healing in the vessel. However, the efficacy and safety of biodegradable polymer drug-eluting stents (BP-DES) vs. bare metal stents (BMS) are unknown. The aim of this study was to perform a meta-analysis of randomized controlled trials (RCTs) comparing the outcomes of BP-DES vs. BMS.
Related JoVE Video
Surface engineered antifouling optomagnetic SPIONs for bimodal targeted imaging of pancreatic cancer cells.
Int J Nanomedicine
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
Targeted imaging contrast agents for early pancreatic ductal adenocarcinoma diagnosis was developed using superparamagnetic iron oxide nanoparticles (SPIONs). For phase transfer of SPIONs, the hydrophobic SPIONs are first treated with tetrafluoroborate and then capped by bovine serum albumin (BSA) via ligand exchange. It was experimentally found that nitrosyl tetrafluoroborate pretreatment and proper structures of molecules are essential to the effective surface functionalization of SPIONs. Nonspecific binding was found to be significantly reduced by BSA surface functionalized hydrophobic SPIONs (BSA·SPIONs). The BSA·SPIONs were monodispersed with an average size of approximately 18.0 nm and stable in a wide pH range and various ionic strengths even after 7 days of storage. The longitudinal and transverse proton relaxation rate (r1, r2) values of the BSA·SPIONs were determined to be 11.6 and 154.2 s(-1) per mM of Fe(3+) respectively. The r2/r1 ratio of 13.3 ensured its application as the T2-weighted magnetic resonance imaging contrast agents. When conjugated with near-infrared fluorescent dye and monoclonal antibody, the (dye)BSA·SPION-monoclonal antibody bioconjugates showed excellent targeting capability with minimal nonspecific binding in the bimodal imaging of pancreatic cancer cells. The experimental approach is facile, environmentally benign, and straightforward, which presents great promise in early cancer diagnosis.
Related JoVE Video
Microbial community functional structures in wastewater treatment plants as characterized by GeoChip.
PLoS ONE
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
Biological WWTPs must be functionally stable to continuously and steadily remove contaminants which rely upon the activity of complex microbial communities. However, knowledge is still lacking in regard to microbial community functional structures and their linkages to environmental variables.
Related JoVE Video
Bacterial community dynamics and taxa-time relationships within two activated sludge bioreactors.
PLoS ONE
PUBLISHED: 01-01-2014
Show Abstract
Hide Abstract
Biological activated sludge process must be functionally stable to continuously remove contaminants while relying upon the activity of complex microbial communities. However the dynamics of these communities are as yet poorly understood. A macroecology metric used to quantify community dynamic is the taxa-time relationship (TTR). Although the TTR of animal and plant species has been well documented, knowledge is still lacking in regard to TTR of microbial communities in activated sludge bioreactors.
Related JoVE Video
Mexican-American childrens perspectives: neighborhood characteristics and physical activity in Texas-Mexico border colonias.
J Environ Health
PUBLISHED: 12-03-2013
Show Abstract
Hide Abstract
The qualitative study described in this article investigated perceptions about environmental factors influencing physical activity (PA) among children from underserved neighborhoods known as colonias in the U.S.-Mexico border. Ten focus groups were conducted with 67 Mexican-American colonia children ages 8 to 13 living in one of the poorest border counties in the U.S. Analyses indicated that PA among children was influenced by neighborhood characteristics, including litter, speeding cars, unleashed dogs, and dark streets. The children also underlined intrapersonal and social environmental factors. Findings may inform policy makers and public health professionals about ways to promote PA among underserved children through urban planning and programs focusing on PA-supportive infrastructure, neighborhood safety, and family- and home-based physical activities.
Related JoVE Video
Fibroblast growth factor-peptide promotes bone marrow recovery after irradiation.
Adv. Exp. Med. Biol.
PUBLISHED: 11-20-2013
Show Abstract
Hide Abstract
Various members of the fibroblast growth factor (FGF) family mitigate radiation-induced damage. We designed and synthesized the binding domain peptide of FGF-2 (FGF-P) with a dimer form resistant to peptidase and examined its mitigatory effect on murine bone marrow cells. NIH Swiss mice were exposed to different doses of total body irradiation (TBI) and treated with ten doses of 5 mg/kg FGF-P. We achieved the following results: (1) FGF-P stimulated the growth of bone marrow cells harvested from mice exposed to 3 Gy; (2) on day 25 after 6 Gy TBI, the number of leukocytes and granulocytes was higher in the FGF-P group than in the vehicle-alone group; (3) FGF-P significantly increased the number of pro-B and pre-B cells; and (4) FGF-P treatment in vivo increased the long-term hematopoietic stem cells (LT-HSC) in bone marrow. These data reveal the underlying mechanism by which FGF-P rescued a significant percentage of the exposed mice. The increase of LT-HSC in bone marrow leads to a concomitant increase of pro-B and pre-B cells followed by leukocytes and granulocytes, which in turn enhance immunity against infection.
Related JoVE Video
Alteration of plasma galactose/N-acetylgalactosamine level after irradiation.
Adv. Exp. Med. Biol.
PUBLISHED: 11-20-2013
Show Abstract
Hide Abstract
Although glycoproteins possess a variety of functional and structural roles in intracellular and intercellular activities, the effect of ionizing radiation (IR) on glycosylation is largely unknown. To explore this effect, we established a sandwich assay in which PHA-L, a phytohaemagglutinin that agglutinates leukocytes, was used as a coating layer to capture glycoproteins containing complex oligosaccharides; the bound glycoproteins were then measured. C57BL/6 mice were exposed to 0, 3, 6, or 10 Gy, and the plasma was collected at 6, 12, 18, 24, 48, 72, or 168 h and then analyzed for galactose/N-acetylgalactosamine (Gal/GalNAc) containing proteins. We found that (1) the sandwich assay accurately measured the level of glycoproteins, (2) 6-12 h after IR, the amount of glycoproteins containing GalNAc increased, and (3) at 72 and 168 h, 10 Gy was associated with a decrease in Gal/GalNAc. These IR-induced alterations might relate to the release of glycoproteins into the blood and the damage of the proteins and genes that are related to the glycosylation process.
Related JoVE Video
In vitro Sirius Red collagen assay measures the pattern shift from soluble to deposited collagen.
Adv. Exp. Med. Biol.
PUBLISHED: 11-20-2013
Show Abstract
Hide Abstract
In this study, we compared two in vitro collagen production assays ([(3)H]-proline incorporation and Sirius Red) for their ability to determine the pattern shift from soluble to deposited collagen. The effect of the antifibrotic agent, triptolide (TPL), on collagen production was also studied. The results showed that: (1) 48 h after NIH 3T3 (murine embryo fibroblast) and HFL-1(human fetal lung fibroblast) were exposed to transforming growth factor-beta 1 (TGF-?), there was an increase in soluble collagen in the culture medium; (2) on day 4, soluble collagen declined, whereas deposited collagen increased; (3) Sirius Red was easier to use than [(3)H]-proline incorporation and more consistently reflected the collagen pattern shift from soluble to deposited; (4) the in vitro Sirius Red assay took less time than the in vivo assay to determine the effect of TPL. Our results suggest that: (a) the newly synthesized soluble collagen can sensitively evaluate an agents capacity for collagen production and (b) Sirius Red is more useful than [(3)H]-proline because it is easier to use, more convenient, less time consuming, and does not require radioactive material.
Related JoVE Video
High-throughput analysis of meiotic crossover frequency and interference via flow cytometry of fluorescent pollen in Arabidopsis thaliana.
Nat Protoc
PUBLISHED: 10-10-2013
Show Abstract
Hide Abstract
During meiosis, reciprocal exchange between homologous chromosomes occurs as a result of crossovers (COs). CO frequency varies within genomes and is subject to genetic, epigenetic and environmental control. As robust measurement of COs is limited by their low numbers, typically 1-2 per chromosome, we adapted flow cytometry for use with Arabidopsis transgenic fluorescent protein-tagged lines (FTLs) that express eCFP, dsRed or eYFP fluorescent proteins in pollen. Segregation of genetically linked transgenes encoding fluorescent proteins of distinct colors can be used to detect COs. The fluorescence of up to 80,000 pollen grains per individual plant can be measured in 10-15 min using this protocol. A key element of CO control is interference, which inhibits closely spaced COs. We describe a three-color assay for the measurement of CO frequency in adjacent intervals and calculation of CO interference. We show that this protocol can be used to detect changes in CO frequency and interference in the fancm zip4 double mutant. By enabling high-throughput measurement of CO frequency and interference, these methods will facilitate genetic dissection of meiotic recombination control.
Related JoVE Video
RNA interference targeting human integrin ?6 suppresses the metastasis potential of hepatocellular carcinoma cells.
Eur. J. Med. Res.
PUBLISHED: 09-25-2013
Show Abstract
Hide Abstract
Increased metastasis has been proved to be associated with a poor prognosis for hepatocellular carcinoma (HCC). There are higher-level expressions of integrin ?6 in the tissues of HCC patients with a higher fatality rate. The aim of this study is to investigate the effect of short hairpin RNA (shRNA) silencing integrin ?6 expression on the proliferation and metastasis in HCC cell lines.
Related JoVE Video
Toll-like receptor 3 plays a role in myocardial infarction and ischemia/reperfusion injury.
Biochim. Biophys. Acta
PUBLISHED: 08-19-2013
Show Abstract
Hide Abstract
Innate immune and inflammatory responses mediated by Toll like receptors (TLRs) have been implicated in myocardial ischemia/reperfusion (I/R) injury. This study examined the role of TLR3 in myocardial injury induced by two models, namely, myocardial infarction (MI) and I/R. First, we examined the role of TLR3 in MI. TLR3 deficient (TLR3(-/-)) and wild type (WT) mice were subjected to MI induced by permanent ligation of the left anterior descending (LAD) coronary artery for 21days. Cardiac function was measured by echocardiography. Next, we examined whether TLR3 contributes to myocardial I/R injury. TLR3(-/-) and WT mice were subjected to myocardial ischemia (45min) followed by reperfusion for up to 3days. Cardiac function and myocardial infarct size were examined. We also examined the effect of TLR3 deficiency on I/R-induced myocardial apoptosis and inflammatory cytokine production. TLR3(-/-) mice showed significant attenuation of cardiac dysfunction after MI or I/R. Myocardial infarct size and myocardial apoptosis induced by I/R injury were significantly attenuated in TLR3(-/-) mice. TLR3 deficiency increases B-cell lymphoma 2 (BCL2) levels and attenuates I/R-increased Fas, Fas ligand or CD95L (FasL), Fas-Associated protein with Death Domain (FADD), Bax and Bak levels in the myocardium. TLR3 deficiency also attenuates I/R-induced myocardial nuclear factor KappaB (NF-?B) binding activity, Tumor necrosis factor alpha (TNF-?) and Interleukin-1 beta (IL-1?) production as well as I/R-induced infiltration of neutrophils and macrophages into the myocardium. TLR3 plays an important role in myocardial injury induced by MI or I/R. The mechanisms involve activation of apoptotic signaling and NF-?B binding activity. Modulation of TLR3 may be an effective approach for ameliorating heart injury in heart attack patients.
Related JoVE Video
Histone deacetylase inhibitor MC1293 induces latent HIV-1 reactivation by histone modification in vitro latency cell lines.
Curr. HIV Res.
PUBLISHED: 08-14-2013
Show Abstract
Hide Abstract
HIV-1 latency remains a major problem for the eradication of viruses in infected individuals. We evaluated the effect of MC1293 on the epigenetic change at HIV-1 LTR and the induction of the latent viruses in the latency Jurkat T cell line. We found MC1293 can activate HIV-1 gene expression, increase the acetylation level of H3 and H4 at the nuc-1 site of HIV-1 LTR. In addition, MC1293 can synergize with prostratin to activate the HIV-1 promoter, and has relatively lower toxicity compared to Trichostatin A (TSA). The results suggest that the acetylation of histone plays an important role in regulating HIV-1 LTR gene expression, and MC1293 is potential drug candidate for antilatency therapies.
Related JoVE Video
Identification of local phase of nanoscale BaTiO? powders by high-resolution electron energy loss spectroscopy.
Microsc. Microanal.
PUBLISHED: 08-08-2013
Show Abstract
Hide Abstract
The electron energy loss spectroscopy (EELS) technique was applied to investigate the local variation in the phase of barium titanate (BaTiO?) ceramics. It was found that the fine structure of the titanium L?,? edge and their satellite peaks were sensitively varied with the tetragonal-cubic phase transition. The peak splitting of Ti-L? edge of tetragonal-phased BaTiO? ceramics was widened because of the increased crystal field effect compared with that of cubic-phased BaTiO?. In case of nanoscale BaTiO? powders, the L? edge splitting of the core region was found to be smaller than that of the shell region. The energy gap between peaks t?g and eg varied from 2.36 to 1.94 eV with changing the probe position from 1 to 20 nm from the surface. These results suggest that the EELS technique can be used to identify the local phase of sintered BaTiO? ceramics.
Related JoVE Video
Zinc-finger-nucleases mediate specific and efficient excision of HIV-1 proviral DNA from infected and latently infected human T cells.
Nucleic Acids Res.
PUBLISHED: 06-26-2013
Show Abstract
Hide Abstract
HIV-infected individuals currently cannot be completely cured because existing antiviral therapy regimens do not address HIV provirus DNA, flanked by long terminal repeats (LTRs), already integrated into host genome. Here, we present a possible alternative therapeutic approach to specifically and directly mediate deletion of the integrated full-length HIV provirus from infected and latently infected human T cell genomes by using specially designed zinc-finger nucleases (ZFNs) to target a sequence within the LTR that is well conserved across all clades. We designed and screened one pair of ZFN to target the highly conserved HIV-1 5-LTR and 3-LTR DNA sequences, named ZFN-LTR. We found that ZFN-LTR can specifically target and cleave the full-length HIV-1 proviral DNA in several infected and latently infected cell types and also HIV-1 infected human primary cells in vitro. We observed that the frequency of excision was 45.9% in infected human cell lines after treatment with ZFN-LTR, without significant host-cell genotoxicity. Taken together, our data demonstrate that a single ZFN-LTR pair can specifically and effectively cleave integrated full-length HIV-1 proviral DNA and mediate antiretroviral activity in infected and latently infected cells, suggesting that this strategy could offer a novel approach to eradicate the HIV-1 virus from the infected host in the future.
Related JoVE Video
Clonal diversity of Acinetobacter baumannii clinical isolates revealed by a snapshot study.
BMC Microbiol.
PUBLISHED: 05-27-2013
Show Abstract
Hide Abstract
Acinetobacter baumannii is a notorious opportunistic pathogen mainly associated with hospital-acquired infections. Studies on the clonal relatedness of isolates could lay the foundation for effective infection control. A snapshot study was performed to investigate the clonal relatedness of A. baumannii clinical isolates in our local settings.
Related JoVE Video
Bioluminescence imaging of caspase-3 activity in mouse liver.
Apoptosis
PUBLISHED: 04-18-2013
Show Abstract
Hide Abstract
Apoptosis is an essential process for the maintenance of liver physiology. The ability to noninvasively image apoptosis in livers would provide unique insights into its role in liver disease processes. In the present work, we established a stable mouse model by hydrodynamics methods to study the activity of caspase-3 and evaluate the effect of the apoptosis inhibitors in mouse livers under true physiological conditions by bioluminescence imaging. The reporter plasmid attB-ANLuc(DEVD)BCLuc that contains fragment of attB and ANLuc(DEVD)BCLuc was codelivered with the mouse-codon optimized ?C31 (?C31o) integrase plasmids specifically to mouse liver by hydrodynamic injection procedure. Then, ?C31o integrase mediated intramolecular recombination between wild-type attB and attP site in mice, and thus the reporter expression cassette attB-ANLuc(DEVD)BCLuc was integrated permanently into mouse liver chromosome. We used these mice to characterize in vivo activation of caspase-3 upon treatment with LPS/D-GalN. Our data show that liver apoptosis could be reflected by the activity of luciferase. The shRNA targeting caspase-3 protein or apoptosis inhibitors could effectively downregulate luciferase activity in vivo. Also, this model could be used to measure caspase-3 activation during inflammatory and infectious events in vivo as verified by infected with MHV-3. This model could be used for screening anti-apoptosis compounds target mouse livers.
Related JoVE Video
Rifampin inhibits Toll-like receptor 4 signaling by targeting myeloid differentiation protein 2 and attenuates neuropathic pain.
FASEB J.
PUBLISHED: 04-08-2013
Show Abstract
Hide Abstract
Rifampin has been used for the treatment of bacterial infections for many years. Clinically, rifampin has been found to possess immunomodulatory effects. However, the molecular target responsible for the immunosuppressive effects of rifampin is not known. Herein, we show that rifampin binds to myeloid differentiation protein 2 (MD-2), the key coreceptor for innate immune TLR4. Rifampin blocked TLR4 signaling induced by LPS, including NF-?B activation and the overproduction of proinflammatory mediators nitric oxide, interleukin 1?, and tumor necrosis factor ? in mouse microglia BV-2 cells and macrophage RAW 264.7 cells. Rifampins inhibition of TLR4 signaling was also observed in immunocompetent rat primary macrophage, microglia, and astrocytes. Further, we show that rifampin (75 or 100 mg/kg b.i.d. for 3 d, intraperitoneal) suppressed allodynia induced by chronic constriction injury of the sciatic nerve and suppressed nerve injury-induced activation of microglia. Our findings indicate that MD-2 is a important target of rifampin in its inhibition of innate immune function and contributes to its clinically observed immune-suppressive effect. The results also suggest that rifampin may be repositioned as an agent for the treatment of neuropathic pain.
Related JoVE Video
Increasing body mass index, blood pressure, and Acanthosis Nigricans abnormalities in school-age children.
J Sch Nurs
PUBLISHED: 04-03-2013
Show Abstract
Hide Abstract
This retrospective quantitative study examined the relationships among gender, Acanthosis Nigricans (AN), body mass index (BMI), and blood pressure (BP) in children attending school Grades 1-9 in Southwest Texas. Of the 34,897 health screening records obtained for the secondary analysis, 32,788 were included for the study. A logistic regression analysis was carried out with AN as the dependent variable, with year, gender, BMI, and BP as independent variables. The results indicate that the rate of children in each grade with three positive markers increased 2% during a 3-year period between 2008 and 2010. In the 5-year period between 2005 and 2010, a clear trend of significantly higher numbers of children with both AN and BMI markers was apparent. Gender played a significant role as females were more likely to have the AN marker than males. Further study is indicated based on the increasing trend of school-age children in Texas with positive markers for AN, increased BMI and BP.
Related JoVE Video
A bioengineered metastatic pancreatic tumor model for mechanistic investigation of chemotherapeutic drugs.
J. Biotechnol.
PUBLISHED: 03-28-2013
Show Abstract
Hide Abstract
Here we bioengineered a metastatic pancreatic tumor model with homogenous human CD133(+)CXCR4(+) cancer stem cells (CSC) and a polyglyconate/gelatin electrospun scaffold. The scaffold sported a highly porous microstructure with the majority of fibers possessing a diameter between 500?m and 1500?m. The scaffold supported the growth of tumor cells without provoking apoptosis. The homogeneous CD133(+)CXCR4(+) CSC was transplanted with the scaffold into the pancreas of nude mice to establish a metastatic pancreatic tumor. After 8 weeks, the tumor volume and weight in the scaffold model were 40.52% and 51.49% greater than the traditional model, respectively. The scaffold also increased the incidence of tumor formation and readily induced a hepatic metastasis. In this model we found that FOLFIRINOX possessed a superior capability of preventing the hepatic metastasis of pancreatic tumor cells than gemcitabine. A mechanistic study attributed this superiority to the fact that FOLFIRINOX could induce a greater apoptosis of CD133(+)CXCR4(+) CSC, thus depriving the driving force of hepatic metastasis. This metastatic tumor model showed an increased incidence of tumor formation, an accelerated tumorigenesis and a significant hepatic metastasis, therefore offering scientists a proven platform to study chemotherapeutic drugs.
Related JoVE Video
Acinetobacter pittii and Acinetobacter nosocomialis among clinical isolates of the Acinetobacter calcoaceticus-baumannii complex in Sichuan, China.
Diagn. Microbiol. Infect. Dis.
PUBLISHED: 03-22-2013
Show Abstract
Hide Abstract
Among 82 clinical isolates of the Acinetobacter calcoaceticus-baumannii complex recovered in 13 hospitals of Sichuan, China, in 2011, 13 were Acinetobacter pittii and 2 were Acinetobacter nosocomialis. Multilocus sequence typing revealed a novel sequence type (ST) of A. nosocomialis and 7 novel STs of A. pittii. Most isolates were hospital-acquired and colonized in the respiratory tract, while 6 cases with pneumonia due to A. pittii were identified. This study provided a snapshot of the local incidence of A. pittii and A. nosocomialis.
Related JoVE Video
Clinical symptoms, immune factors, and molecular characteristics of an adult male in Shenzhen, China infected with influenza virus H5N1.
J. Med. Virol.
PUBLISHED: 03-20-2013
Show Abstract
Hide Abstract
On December 29, 2011, a man infected with a subclade of the H5N1 virus was confirmed in Shenzhen, China. The clinical symptoms and immune factors of the patient were investigated and the phylogenetic and molecular characteristics of the virus were analyzed. High fever, rapid development of serious pneumonia and multi-organ failure were the main clinical symptoms. Arterial blood gas analysis showed that PaCO2 rose sharply and PO2 decreased. Leukocyte and platelet counts decreased rapidly. Peripheral blood lymphocyte counts indicated lymphopenia and inverted ratios of CD4(+) to CD8(+) cells. Cytokine analysis showed that the levels of serum IL-6, IL-10, and IFN-r continued to increase, whereas the levels of IL-12 and TNFs decreased during the clinical course. MCP-1 and IP-10 remained at a high level after infection. Phylogenetic analysis confirmed that the virus A/Shenzhen/1/2011 belongs to the new subclade 2.3.2.1. An Arg (R) insertion at P6 and an RP8I substitution in the HA cleavage site motif were detected in the virus. Compared to the vaccine strain, 16 specific substitutions occurred in the HA1 protein. Some of them were located on the receptor-binding site, glycosylation site and the region of the antigenic determinant. In summary, serious complications and immune system disorders were the main features of the infection with H5N1. Gene variation did not weaken the highly pathogenic features of viruses and the pathogenicity and antigenicity of the new subclade virus were changed.
Related JoVE Video
Targeting Toll-like receptors with small molecule agents.
Chem Soc Rev
PUBLISHED: 03-19-2013
Show Abstract
Hide Abstract
Toll-like receptors (TLRs) are type I transmembrane proteins that are key regulators of both innate and adaptive immune responses. To protect the host from viral and bacterial threats, TLRs trigger a pro-inflammatory immune response by detecting pathogen and danger associated molecular patterns. Considerable evidence has accumulated to show that the dysregulation of TLR signaling contributes to the development and progression of numerous diseases. Therefore, TLRs are emerging as important drug discovery targets. Currently, there is great interest in the development of TLR small molecule modulators for interrogating TLR signaling and treating diseases caused by TLR signaling malfunctions. In this tutorial review, we will outline methods for the discovery of TLR small molecule modulators and the up-to-date progress in this field. Small molecules targeting TLRs not only provide an opportunity to identify promising drug candidates, but also unveil knowledge regarding TLR signaling pathways.
Related JoVE Video
An integrated city-driven perinatal HIV prevention program covering 1.8 million pregnant women in Shenzhen, China, 2000 to 2010.
Sex Transm Dis
PUBLISHED: 03-15-2013
Show Abstract
Hide Abstract
Despite the scale-up of prevention of mother-to-child transmission (PMTCT) programs worldwide, the translation from research studies into public health policy has been slow. This report details the experiences of a city-driven PMTCT program in China using existing health resources.
Related JoVE Video
Involvement of histone methyltransferase GLP in HIV-1 latency through catalysis of H3K9 dimethylation.
Virology
PUBLISHED: 02-20-2013
Show Abstract
Hide Abstract
Understanding the mechanism of HIV-1 latency is crucial to eradication of the viral reservoir in HIV-1-infected individuals. However, the role of histone methyltransferase (HMT) G9a-like protein (GLP) in HIV-1 latency is still unclear. In the present work, we established four clonal cell lines containing HIV-1 vector. We found that the integration sites of most clonal cell lines favored active gene regions. However, we also observed hypomethylation of CpG of HIV 5LTR in all four clonal cell lines. Additionally, 5-deoxy-5-methylthioadenosine (MTA), a broad-spectrum histone methyltransferase inhibitor, was used to examine the role of histone methylation in HIV-1 latency. MTA was found to decrease the level of H3K9 dimethylation, causing reactivation of latent HIV-1 in C11 cells. GLP knockdown by small interfering RNA clearly induced HIV-1 LTR expression. Results suggest that GLP may play a significant role in the maintenance of HIV-1 latency by catalyzing dimethylation of H3K9.
Related JoVE Video
Toll-like receptors as therapeutic targets for autoimmune connective tissue diseases.
Pharmacol. Ther.
PUBLISHED: 02-18-2013
Show Abstract
Hide Abstract
Autoimmune connective tissue diseases (ACTDs) are a family of consistent systemic autoimmune inflammatory disorders, including systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), systemic sclerosis (SSc) and Sjögrens syndrome (SS). IL-1R-like receptors (TLRs) are located on various cellular membranes and sense exogenous and endogenous danger-associated molecular patterns (DAMPs) and pathogen-associated molecular patterns (PAMPs), playing a critical role in innate immune responses. During the past decade, the investigation of TLRs in inflammatory autoimmune diseases has been fruitful. In this report, we review the significant biochemical, physiological and pathological studies of the key functions of TLRs in ACTDs. Several proteins in the TLR signaling pathways (e.g., IKK-2 and MyD88) have been identified as potential therapeutic targets for the treatment of ACTDs. Antibodies, oligodeoxyribonucleotides (ODNs) and small molecular inhibitors (SMIs) have been tested to modulate TLR signaling. Some drug-like SMIs of TLR signaling, such as RDP58, ST2825, ML120B and PHA-408, have demonstrated remarkable potential, with promising safety and efficacy profiles, which should warrant further clinical investigation. Nonetheless, one should bear in mind that all TLRs exert both protective and pathogenic functions; the function of TLR4 in inflammatory bowel disease represents such an example. Therefore, an important aspect of TLR modulator development involves the identification of a balance between the suppression of disease-inducing inflammation, while retaining the beneficiary host immune response.
Related JoVE Video
The Toll-like receptor 9 ligand, CpG oligodeoxynucleotide, attenuates cardiac dysfunction in polymicrobial sepsis, involving activation of both phosphoinositide 3 kinase/Akt and extracellular-signal-related kinase signaling.
J. Infect. Dis.
PUBLISHED: 01-28-2013
Show Abstract
Hide Abstract
Toll-like receptors (TLRs) play a role in the pathophysiology of sepsis and multiple organ failure. This study examined the effect of CpG oligodeoxynucleotide (CpG-ODN), the TLR9 ligand, on polymicrobial sepsis-induced cardiac dysfunction.
Related JoVE Video
Expression of neutral ?-glucosidase from Scytalidium thermophilum in Candida glabrata for ethanol production from alkaline-pretreated rice straw.
J. Biosci. Bioeng.
PUBLISHED: 01-18-2013
Show Abstract
Hide Abstract
We successfully expressed the neutral ?-glucosidase (BGL4) from Scytalidium thermophilum in the thermotolerant yeast Candida glabrata. Compared to the strain expressing Aspergillus acidic ?-glucosidase (BGL1), the BGL4-expressing strain showed a higher cellobiose fermentation ability at pH 6.0 and 40°C, leading to a higher ethanol production from alkaline-pretreated rice straw.
Related JoVE Video
Gene-guided gefitinib switch maintenance therapy for patients with advanced EGFR mutation-positive non-small cell lung cancer: an economic analysis.
BMC Cancer
PUBLISHED: 01-16-2013
Show Abstract
Hide Abstract
Maintenance therapy with gefitinib notably improves survival in patients with advanced non-small cell lung cancer (NSCLC) and EGFR mutation-positive tumors, but the economic impact of this practice is unclear.
Related JoVE Video
Establishment of Stable Reporter Expression for In Vivo Imaging of Nuclear Factor-?B Activation in Mouse Liver.
Theranostics
PUBLISHED: 01-01-2013
Show Abstract
Hide Abstract
The nuclear factor-?B (NF-?B) signaling pathway plays a critical role in a multitude of cellular processes. Activation of the NF-?B transcription factor family is essential for the initiation of inflammation, immunity, cell proliferation and apoptosis through a list of responsive genes. In hepatic tissue, activation of the NF-?B pathway has been implicated in a number of pathological conditions. Here we described a mouse model for noninvasive quantification of NF-?B activation in the hepatic tissues. Mice were subjected to hydrodynamic delivery with a mixture of pattB-NF-?B-Fluc reporter and ?C31o integrase vector. Hepatic expression of ?C31o integrase mediated chromosomal integration of the pattB-NF-?B-Fluc reporter, resulting in stable luciferase expression at 300 days post transfection. We applied noninvasive imaging and were able to detect NF-?B activation under acute liver injury and hepatitis conditions. During hepatectomy-induced liver regeneration, NF-?B activation was detected locally in the tissues at the surgery site. Treatment with Sorafenib suppressed NF-?B activation, accompanied with perturbation of liver regeneration. In conclusion, we established a method for stable transfection of the hepatic tissues and applied the transfected mice to longitudinal monitoring of NF-?B activity under pathological conditions. Further exploration of this methodology for establishment of other disease models and for evaluation of novel pharmaceuticals is likely to be fruitful.
Related JoVE Video
Smart Caching Based on Mobile Agent of Power WebGIS Platform.
ScientificWorldJournal
PUBLISHED: 01-01-2013
Show Abstract
Hide Abstract
Power information construction is developing towards intensive, platform, distributed direction with the expansion of power grid and improvement of information technology. In order to meet the trend, power WebGIS was designed and developed. In this paper, we first discuss the architecture and functionality of power WebGIS, and then we study caching technology in detail, which contains dynamic display cache model, caching structure based on mobile agent, and cache data model. We have designed experiments of different data capacity to contrast performance between WebGIS with the proposed caching model and traditional WebGIS. The experimental results showed that, with the same hardware environment, the response time of WebGIS with and without caching model increased as data capacity growing, while the larger the data was, the higher the performance of WebGIS with proposed caching model improved.
Related JoVE Video
A tissue-engineered subcutaneous pancreatic cancer model for antitumor drug evaluation.
Int J Nanomedicine
PUBLISHED: 01-01-2013
Show Abstract
Hide Abstract
The traditional xenograft subcutaneous pancreatic cancer model is notorious for its low incidence of tumor formation, inconsistent results for the chemotherapeutic effects of drug molecules of interest, and a poor predictive capability for the clinical efficacy of novel drugs. These drawbacks are attributed to a variety of factors, including inoculation of heterogeneous tumor cells from patients with different pathological histories, and use of poorly defined Matrigel(®). In this study, we aimed to tissue-engineer a pancreatic cancer model that could readily cultivate a pancreatic tumor derived from highly homogenous CD24(+)CD44(+) pancreatic cancer stem cells delivered by a well defined electrospun scaffold of poly(glycolide-co-trimethylene carbonate) and gelatin. The scaffold supported in vitro tumorigenesis from CD24(+)CD44(+) cancer stem cells for up to 7 days without inducing apoptosis. Moreover, CD24(+)CD44(+) cancer stem cells delivered by the scaffold grew into a native-like mature pancreatic tumor within 8 weeks in vivo and exhibited accelerated tumorigenesis as well as a higher incidence of tumor formation than the traditional model. In the scaffold model, we discovered that oxaliplatin-gemcitabine (OXA-GEM), a chemotherapeutic regimen, induced tumor regression whereas gemcitabine alone only capped tumor growth. The mechanistic study attributed the superior antitumorigenic performance of OXA-GEM to its ability to induce apoptosis of CD24(+)CD44(+) cancer stem cells. Compared with the traditional model, the scaffold model demonstrated a higher incidence of tumor formation and accelerated tumor growth. Use of a tiny population of highly homogenous CD24(+)CD44(+) cancer stem cells delivered by a well defined scaffold greatly reduces the variability associated with the traditional model, which uses a heterogeneous tumor cell population and poorly defined Matrigel. The scaffold model is a robust platform for investigating the antitumorigenesis mechanism of novel chemotherapeutic drugs with a special focus on cancer stem cells.
Related JoVE Video

What is Visualize?

JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

How does it work?

We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

Video X seems to be unrelated to Abstract Y...

In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.