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Find video protocols related to scientific articles indexed in Pubmed.
Expression and significance of fat mass and obesity associated gene and forkhead transcription factor O1 in non-alcoholic fatty liver disease.
Chin. Med. J.
PUBLISHED: 11-11-2014
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Non-alcoholic fatty liver disease (NAFLD) is a complex disorder and has been closely linked to obesity. The fat mass and obesity-associated (FTO) gene is a newly discovered gene related to obesity, which enhances oxidative stress and lipogenesis in NAFLD. The forkhead transcription factor O1 (FoxO1) is another important gene involved in NAFLD, which causes lipid disorders when insulin resistance appears in the liver. However, the interactions between FTO and FoxO1 during the pathogenesis of NAFLD have not been fully elucidated. This study was designed to identify the relationship between these two factors that are involved in the development of NAFLD.
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Large area and depth-profiling dislocation imaging and strain analysis in Si/SiGe/Si heterostructures.
Microsc. Microanal.
PUBLISHED: 08-27-2014
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We demonstrate the combined use of large area depth-profiling dislocation imaging and quantitative composition and strain measurement for a strained Si/SiGe/Si sample based on nondestructive techniques of electron beam-induced current (EBIC) and X-ray diffraction reciprocal space mapping (XRD RSM). Depth and improved spatial resolution is achieved for dislocation imaging in EBIC by using different electron beam energies at a low temperature of ~7 K. Images recorded clearly show dislocations distributed in three regions of the sample: deep dislocation networks concentrated in the "strained" SiGe region, shallow misfit dislocations at the top Si/SiGe interface, and threading dislocations connecting the two regions. Dislocation densities at the top of the sample can be measured directly from the EBIC results. XRD RSM reveals separated peaks, allowing a quantitative measurement of composition and strain corresponding to different layers of different composition ratios. High-resolution scanning transmission electron microscopy cross-section analysis clearly shows the individual composition layers and the dislocation lines in the layers, which supports the EBIC and XRD RSM results.
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SDF-1? stiffens myeloma bone marrow mesenchymal stromal cells through the activation of RhoA-ROCK-Myosin II.
Int. J. Cancer
PUBLISHED: 08-18-2014
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Multiple myeloma (MM) is a B lymphocyte malignancy that remains incurable despite extensive research efforts. This is due, in part, to frequent disease recurrences associated with the persistence of myeloma cancer stem cells (mCSCs). Bone marrow mesenchymal stromal cells (BMSCs) play critical roles in supporting mCSCs through genetic or biochemical alterations. Previously, we identified mechanical distinctions between BMSCs isolated from MM patients (mBMSCs) and those present in the BM of healthy individuals (nBMSCs). These properties of mBMSC contributed to their ability to preferentially support mCSCs. To further illustrate mechanisms underlying the differences between mBMSCs and nBMSCs, here we report that (i) mBMSCs express an abnormal, constitutively high level of phosphorylated Myosin II, which leads to stiffer membrane mechanics, (ii) mBMSCs are more sensitive to SDF-1?-induced activation of MYL2 through the G(i./o) -PI3K-RhoA-ROCK-Myosin II signaling pathway, affecting Young's modulus in BMSCs and (iii) activated Myosin II confers increased cell contractile potential, leading to enhanced collagen matrix remodeling and promoting the cell-cell interaction between mCSCs and mBMSCs. Together, our findings suggest that interfering with SDF-1? signaling may serve as a new therapeutic approach for eliminating mCSCs by disrupting their interaction with mBMSCs.
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Determining the resolution limits of electron-beam lithography: direct measurement of the point-spread function.
Nano Lett.
PUBLISHED: 06-30-2014
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One challenge existing since the invention of electron-beam lithography (EBL) is understanding the exposure mechanisms that limit the resolution of EBL. To overcome this challenge, we need to understand the spatial distribution of energy density deposited in the resist, that is, the point-spread function (PSF). During EBL exposure, the processes of electron scattering, phonon, photon, plasmon, and electron emission in the resist are combined, which complicates the analysis of the EBL PSF. Here, we show the measurement of delocalized energy transfer in EBL exposure by using chromatic aberration-corrected energy-filtered transmission electron microscopy (EFTEM) at the sub-10 nm scale. We have defined the role of spot size, electron scattering, secondary electrons, and volume plasmons in the lithographic PSF by performing EFTEM, momentum-resolved electron energy loss spectroscopy (EELS), sub-10 nm EBL, and Monte Carlo simulations. We expect that these results will enable alternative ways to improve the resolution limit of EBL. Furthermore, our approach to study the resolution limits of EBL may be applied to other lithographic techniques where electrons also play a key role in resist exposure, such as ion-beam-, X-ray-, and extreme-ultraviolet lithography.
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Visualization of hierarchical nanodomains in polymer/fullerene bulk heterojunction solar cells.
Microsc. Microanal.
PUBLISHED: 06-20-2014
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Traditional electron microscopy techniques such as bright-field imaging provide poor contrast for organic films and identification of structures in amorphous material can be problematic, particularly in high-performance organic solar cells. By combining energy-filtered corrected transmission electron microscopy, together with electron energy loss and X-ray energy-dispersive hyperspectral imaging, we have imaged PTB7/PC61BM blended polymer optical photovoltaic films, and were able to identify domains ranging in size from several hundred nanometers to several nanometers in extent. This work verifies that microstructural domains exist in bulk heterojunctions in PTB7/PC61BM polymeric solar cells at multiple length scales and expands our understanding of optimal device performance providing insight for the design of even higher performance cells.
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Real-time observation of local strain effects on nonvolatile ferroelectric memory storage mechanisms.
Nano Lett.
PUBLISHED: 05-16-2014
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We use in situ transmission electron microscopy to directly observe, at high temporal and spatial resolution, the interaction of ferroelectric domains and dislocation networks within BiFeO3 thin films. The experimental observations are compared with a phase field model constructed to simulate the dynamics of domains in the presence of dislocations and their resulting strain fields. We demonstrate that a global network of misfit dislocations at the film-substrate interface can act as nucleation sites and slow down domain propagation in the vicinity of the dislocations. Networks of individual threading dislocations emanating from the film-electrode interface play a more dramatic role in pinning domain motion. These dislocations may be responsible for the domain behavior in ferroelectric thin-film devices deviating from conventional Kolmogorov-Avrami-Ishibashi dynamics toward a Nucleation Limited Switching model.
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High throughput quantitative reverse transcription PCR assays revealing over-expression of cancer testis antigen genes in multiple myeloma stem cell-like side population cells.
Br. J. Haematol.
PUBLISHED: 04-09-2014
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Multiple myeloma (MM) stem cells, proposed to be responsible for the tumourigenesis, drug resistance and recurrence of this disease, are enriched in the cancer stem cell-like side population (SP). Cancer testis antigens (CTA) are attractive targets for immunotherapy because they are widely expressed in cancers but only in limited types of normal tissues. We designed a high throughput assay, which allowed simultaneous relative quantifying expression of 90 CTA genes associated with MM. In the three MM cell lines tested, six CTA genes were over-expressed in two and LUZP4 and ODF1 were universally up-regulated in all three cell lines. Subsequent study of primary bone marrow (BM) from eight MM patients and four healthy donors revealed that 19 CTA genes were up-regulated in SP of MM compared with mature plasma cells. In contrast, only two CTA genes showed a moderate increase in SP cells of healthy BM. Furthermore, knockdown using small interfering RNA (siRNA) revealed that LUZP4 expression is required for colony-forming ability and drug resistance in MM cells. Our findings indicate that multiple CTA have unique expression profiles in MM SP, suggesting that CTA may serve as targets for immunotherapy that it specific for MM stem cells and which may lead to the long-term cure of MM.
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Role of programmed death ligands in effective T-cell interactions in extranodal natural killer/T-cell lymphoma.
Oncol Lett
PUBLISHED: 04-03-2014
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Extranodal natural killer/T-cell lymphoma (ENKL) is marked by a profound cellular immune deficiency that may influence the capacity of T cells to extract an efficient antitumor immune response. It has been confirmed that the B7-CD28 pathway may promote tumor immune evasion by providing a negative regulatory signal. The current study analyzed the expression of programmed death 1 (PD-1)/programmed death ligand (PD-L) in ENKL cell lines and tissues. The functional studies were performed to analyze the functional activity of PD-L1 interacting with effective T cells in ENKL. PD-L1 and PD-L2 mRNA levels in ENKL cell lines were markedly upregulated compared with those in normal natural killer cells. The proteins constitutively expressed in the 30 ENKL specimens were significantly higher than in the 20 rhinitis specimens. In addition, PD-L1 and PD-L2 expression were found to closely correlate with certain clinical histopathological parameters. Furthermore, the count of PD-1(+) tumor-infiltrating T lymphocytes was found to negatively correlate with the expression of PD-L1 and PD-L2. The PD-1 expression in the CD4(+) and CD8(+) T-cell subsets of 20 ENKL patients prior to therapy were significantly higher than that of the 10 healthy volunteers. In the functional studies, the cytokines (interleukin-2 and interferon-?) secreted by CD8(+) T cells were inhibited by PD-L1 expression in SNK-6 cells and this was restored with the presence of the PD-L1 blocking antibody. However no direct effect of PD-L1 was identified on CD8(+) T-cell apoptosis and CD8(+) T-cell cytotoxicity, as assessed by the proliferation of SNK-6 cells in the presence or absence of the neutralizing anti-PD-L1 antibody. The results of the current study revealed that PD-Ls and PD-1 are aberrantly expressed in ENKL and, furthermore, PD-L1 expression in SNK-6 cells was found to inhibit the activity of CD8(+) T-cell cytokine secretion. This indicated that the PD-Ls may prevent effective antitumor immunity in vivo by interacting with tumor T cells, which provides important evidence to delineate the cellular immune deficiency mechanism in ENKL. Therefore, PD-1/PD-Ls are predicted to become novel targets for ENKL immunotherapy.
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Effectiveness of gemcitabine, pegaspargase, cisplatin, and dexamethasone (DDGP) combination chemotherapy in the treatment of relapsed/refractory extranodal NK/T cell lymphoma: a retrospective study of 17 patients.
Ann. Hematol.
PUBLISHED: 04-02-2014
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The prognosis of extranodal nature killer (NK)/T cell lymphoma (ENKL) is dismal because of its aggressive course and multidrug resistance. Currently, for patients with relapsed/refractory ENKL, L-asparaginase-based regimens such as L-asparaginase, ifosfamide, methotrexate, etoposide, and dexamethasone (SMILE) or L-asparaginase, methotrexate, and dexamethasone (AspaMetDex) are recommended. We retrospectively investigated the efficacy and safety of gemcitabine, pegaspargase, cisplatin, and dexamethasone (DDGP) combination chemotherapy in the treatment of 17 relapsed/refractory ENKL patients. Clinical data from these patients were collected and analyzed. The primary end point was overall response rate (ORR). All patients were subjected to 2 to 6 cycles of DDGP chemotherapy, and the median number of cycles of DDGP regimen administrated was four. The ORR was 88.2 % (15/17), with nine patients (52.9 %) achieved complete response (CR) and six patients (35.3 %) achieved partial response (PR). The median follow-up time was 17 months (range 2-28 months). The 1-year overall survival (OS) rate and 1-year progression-free survival (PFS) were 82.4 and 64.7 %, respectively. For those CR responders, the median PFS was 17 months. Grade 3/4 neutropenia occurred in nine patients (52.9 %) and grade 3/4 thrombocytopenia occurred in six patients (35.3 %). DDGP combination chemotherapy produces favorable outcomes in relapsed/refractory ENKL, and more attention should be paid to treatment-related myelosuppression. Further prospective trials are expected to define the efficacy.
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Study of the voltammetric behavior of jatrorrhizine and its sensitive determination at electrochemical pretreatment glassy carbon electrode.
Talanta
PUBLISHED: 03-10-2014
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A simple, inexpensive and highly sensitive electrochemical method for the determination of jatrorrhizine was developed using an electrochemically pretreated glassy carbon electrode (EPGCE). The electrochemical behavior of jatrorrhizine was systematically investigated in detail and some kinetic parameters were calculated for the first time. A reasonable reaction mechanism of jatrorrhizine on the EPGCE was also discussed and proposed, which could be a reference for the pharmacological action of jatrorrhizine in clinical study. And the first electroanalytical method of jatrorrhizine was established with a wide linear range from 7.0×10(-8) to 2.0×10(-5)mol L(-1) and a low detection limit of 5.0×10(-8)mol L(-1). The proposed method was successfully applied in determination of jatrorrhizine in pharmaceutical sample, Tinospora capillipes Gagnep (a traditional Chinese medicine), with satisfactory results.
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Characterization of p38 MAPK isoforms for drug resistance study using systems biology approach.
Bioinformatics
PUBLISHED: 03-10-2014
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p38 mitogen-activated protein kinase activation plays an important role in resistance to chemotherapeutic cytotoxic drugs in treating multiple myeloma (MM). However, how the p38 mitogen-activated protein kinase signaling pathway is involved in drug resistance, in particular the roles that the various p38 isoforms play, remains largely unknown.
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Hypoxia-inducible factor-1? C1772T polymorphism and cancer risk: a meta-analysis including 18,334 subjects.
Cancer Invest.
PUBLISHED: 02-27-2014
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Studies on HIF 1? C1772T (P582S) polymorphism revealed a genetic susceptibility to malignant tumors, however, the results were conflicting. We conducted a meta-analysis utilizing 29 eligible case-control studies to analyze the data concerning the association between the HIF-1? C1772T polymorphism and cancer risks. There was statistical association between the HIF-1? CT/TT genotype and cancer risk (OR = 1.28, 95% CI = 1.06-1.54, P(heterogeneity) < .00001). The stability of these observations was confirmed by a one-way sensitivity analysis. Our findings suggested that CT/TT genotype was associated with increased risks of prostate cancer. Besides, the HIF-1? C1772T polymorphism most likely contributes to susceptibility to malignant tumors, especially in American population.
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Asparagine synthetase expression and its potential prognostic value in patients with NK/T cell lymphoma.
Oncol. Rep.
PUBLISHED: 02-21-2014
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Natural killer (NK)/T cell lymphoma usually shows a highly aggressive clinical course and the overall prognosis is poor. At present, there are no standard therapeutic regimens for this disease. Although chemotherapeutic protocols containing L-asparaginase (L-Asp) or pegaspargase (PEG?Asp) have improved the efficacy of treatment, some patients are resistant to L-Asp or PEG-Asp. Previous studies demonstrated that the elevated expression of asparagine synthetase (ASNS) is correlated with the resistance to L-Asp or PEG-Asp and may also affect the prognosis in some types of tumors, but the expression level and clinical significance of ASNS in NK/T cell lymphoma remain unknown. Therefore, we investigated the expression and clinical significance of ASNS in lymphoma cell lines and patients with NK/T cell lymphoma. Firstly, we detected PEG-Asp and L-Asp activity using MTT assay and expression of ASNS using real-time PCR in the 7 lymphoma cell lines. Secondly, we used branched DNA-liquidchip technology (bDNA-LCT) for detecting ASNS mRNA in formalin-fixed, paraffin-embedded tissue sections in 50 cases of NK/T cell lymphoma and in 12 cases of nasal polyps and chronic rhinitis. Moreover, we analyzed the correlations between the expression of ASNS and the sensitivity to L-Asp and PEG-Asp in 7 lymphoma cell lines and with clinicopathological features and prognosis of NK/T cell lymphoma patients who used chemotherapy containing L-Asp and PEG-Asp. There was a marked difference in the sensitivity to L-Asp and PEG-Asp of the 7 lymphoma cell lines. YTS and SNK-6 cells were highly sensitive to PEG-Asp and had relatively low levels of ASNS mRNA expression. Hut-78, Jurkat and Karpas 299 cells were naturally resistant to PEG-Asp, and the ASNS expression levels were extremely high. The expression level of ASNS was relatively low in the NK/T cell lymphoma tissue compared to levels in the nasal polyps and chronic rhinitis (0.480±0.307 vs. 0.739±0.267; P=0.009). ASNS expression level was associated with III-IV tumor stage (P=0.041) and a high International Prognostic Index (P=0.018) in patients with NK/T cell lymphoma. The NK/T cell lymphoma patients with higher ASNS expression had a reduced median survival time when compared with the survival of patients with low ASNS expression (P=0.033). Cox regression test showed that the ASNS expression level is an independent prognostic factor for NK/T cell lymphoma patients. In conclusion, the expression of ASNS was closely related with the sensitivity of lymphoma cell lines to L-Asp and PEG-Asp in vitro and also had a certain effect on the survival of NK/T cell lymphoma patients. In conclusion, high ASNS expression in NK/T cell lymphoma is correlated with worse clinicopathological features.
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Effect of the size-selective silver clusters on lithium peroxide morphology in lithium-oxygen batteries.
Nat Commun
PUBLISHED: 02-06-2014
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Lithium-oxygen batteries have the potential needed for long-range electric vehicles, but the charge and discharge chemistries are complex and not well understood. The active sites on cathode surfaces and their role in electrochemical reactions in aprotic lithium-oxygen cells are difficult to ascertain because the exact nature of the sites is unknown. Here we report the deposition of subnanometre silver clusters of exact size and number of atoms on passivated carbon to study the discharge process in lithium-oxygen cells. The results reveal dramatically different morphologies of the electrochemically grown lithium peroxide dependent on the size of the clusters. This dependence is found to be due to the influence of the cluster size on the formation mechanism, which also affects the charge process. The results of this study suggest that precise control of subnanometre surface structure on cathodes can be used as a means to improve the performance of lithium-oxygen cells.
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Electron-induced Ti-rich surface segregation on SrTiO3 nanoparticles.
Micron
PUBLISHED: 02-04-2014
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Atomic surface structures of nanoparticles are of interest in catalysis and other fields. Aberration-corrected HREM facilitates direct imaging of the surfaces of nanoparticles. A remaining concern of surface imaging arises from beam damage. It is important to identify the intrinsic surface structures and the ones created by electron beam irradiation in TEM. In this study, we performed aberration-corrected HREM and EELS to demonstrate that TiO and bcc type Ti islands form due to intense electron irradiation. The formation of Ti-rich islands is in agreement with previous high temperature annealing experiments on the surfaces of SrTiO3 single crystals.
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Overactive bladder symptom score to evaluate efficacy of solifenacin for the treatment of overactive bladder symptoms.
Chin. Med. J.
PUBLISHED: 01-21-2014
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Overactive bladder (OAB) is a series of symptoms with high prevalence in elderly people. This study was conducted using the overactive bladder symptom score (OABSS) to evaluate the efficacy of solifenacin succinate for the treatment of OAB.
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Serum and urinary procollagen III aminoterminal propeptide as a biomarker of obstructive nephropathy in children.
Clin. Chim. Acta
PUBLISHED: 01-13-2014
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Ureteropelvic junction obstruction (UPJO) is the most common cause of chronic renal failure in children. Rapid diagnosis is important to preserve function and/or to slow down renal injury. This study was to examine serum and urinary procollagen III aminoterminal propeptide (sPIIINP/uPIIINP) protein as potential biomarkers of obstruction in hydronephrosis.
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Dynamic balance of multiple myeloma clonogenic side population cell percentages controlled by environmental conditions.
Int. J. Cancer
PUBLISHED: 01-06-2014
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Cancer stem cells are key drivers of tumor progression and disease recurrence in multiple myeloma (MM). However, little is known about the regulation of MM stem cells. Here, we show that a population of MM cells, known as the side population (SP), exhibits stem-like properties. Cells that constitute the SP in primary MM isolates are negative or seldom expressed for CD138 and CD20 markers. In addition, the SP population contains stem cells that belong to the same lineage as the mature neoplastic plasma cells. Importantly, our data indicate that the SP and nonside population (NSP) percentages in heterogeneous MM cells are balanced, and that this balance can be achieved through a prolonged in vitro culture. Furthermore, we show that SP cells, with confirmed molecular characteristics of MM stem cells, can be regenerated from purified NSP cell populations. We also show that the percentage of SP cells can be enhanced by the hypoxic stress, which is frequently observed within MM tumors. Finally, hypoxic stress enhanced the expression of transforming growth factor ?1 (TGF-?1) and blocking the TGF-?1 signaling pathway inhibited the NSP dedifferentiation. Taken together, these findings indicate that the balance between MM SP and NSP is regulated by environmental factors and TGF-?1 pathway is involved in hypoxia-induced increase of SP population. Understanding the mechanisms that facilitate SP maintenance will accelerate the design of novel therapeutics aimed at controlling these cells in MM.
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Targeting the biophysical properties of the myeloma initiating cell niches: a pharmaceutical synergism analysis using multi-scale agent-based modeling.
PLoS ONE
PUBLISHED: 01-01-2014
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Multiple myeloma, the second most common hematological cancer, is currently incurable due to refractory disease relapse and development of multiple drug resistance. We and others recently established the biophysical model that myeloma initiating (stem) cells (MICs) trigger the stiffening of their niches via SDF-1/CXCR4 paracrine; The stiffened niches then promote the colonogenesis of MICs and protect them from drug treatment. In this work we examined in silico the pharmaceutical potential of targeting MIC niche stiffness to facilitate cytotoxic chemotherapies. We first established a multi-scale agent-based model using the Markov Chain Monte Carlo approach to recapitulate the niche stiffness centric, pro-oncogenetic positive feedback loop between MICs and myeloma-associated bone marrow stromal cells (MBMSCs), and investigated the effects of such intercellular chemo-physical communications on myeloma development. Then we used AMD3100 (to interrupt the interactions between MICs and their stroma) and Bortezomib (a recently developed novel therapeutic agent) as representative drugs to examine if the biophysical properties of myeloma niches are drugable. Results showed that our model recaptured the key experimental observation that the MBMSCs were more sensitive to SDF-1 secreted by MICs, and provided stiffer niches for these initiating cells and promoted their proliferation and drug resistance. Drug synergism analysis suggested that AMD3100 treatment undermined the capability of MICs to modulate the bone marrow microenvironment, and thus re-sensitized myeloma to Bortezomib treatments. This work is also the first attempt to virtually visualize in 3D the dynamics of the bone marrow stiffness during myeloma development. In summary, we established a multi-scale model to facilitate the translation of the niche-stiffness centric myeloma model as well as experimental observations to possible clinical applications. We concluded that targeting the biophysical properties of stem cell niches is of high clinical potential since it may re-sensitize tumor initiating cells to chemotherapies and reduce risks of cancer relapse.
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Imaging the Atomic Surface Structures of CeO2 Nanoparticles.
Nano Lett.
PUBLISHED: 12-05-2013
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Atomic surface structures of CeO2 nanoparticles are under debate owing to the lack of clear experimental determination of the oxygen atom positions. In this study, with oxygen atoms clearly observed using aberration-corrected high-resolution electron microscopy, we determined the atomic structures of the (100), (110), and (111) surfaces of CeO2 nanocubes. The predominantly exposed (100) surface has a mixture of Ce, O, and reduced CeO terminations, underscoring the complex structures of this polar surface that previously was often oversimplified. The (110) surface shows "sawtooth-like" (111) nanofacets and flat CeO2-x terminations with oxygen vacancies. The (111) surface has an O termination. These findings can be extended to the surfaces of differently shaped CeO2 nanoparticles and provide insight about face-selective catalysis.
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Pressure-induced amorphization in single-crystal Ta2O5 nanowires: a kinetic mechanism and improved electrical conductivity.
J. Am. Chem. Soc.
PUBLISHED: 09-06-2013
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Pressure-induced amorphization (PIA) in single-crystal Ta2O5 nanowires is observed at 19 GPa, and the obtained amorphous Ta2O5 nanowires show significant improvement in electrical conductivity. The phase transition process is unveiled by monitoring structural evolution with in situ synchrotron X-ray diffraction, pair distribution function, Raman spectroscopy, and transmission electron microscopy. The first principles calculations reveal the phonon modes softening during compression at particular bonds, and the analysis on the electron localization function also shows bond strength weakening at the same positions. On the basis of the experimental and theoretical results, a kinetic PIA mechanism is proposed and demonstrated systematically that amorphization is initiated by the disruption of connectivity between polyhedra (TaO6 octahedra or TaO7 bipyramids) at the particular weak-bonding positions along the a axis in the unit cell. The one-dimensional morphology is well-preserved for the pressure-induced amorphous Ta2O5, and the electrical conductivity is improved by an order of magnitude compared to traditional amorphous forms. Such pressure-induced amorphous nanomaterials with unique properties surpassing those in either crystalline or conventional amorphous phases hold great promise for numerous applications in the future.
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Biostable ssDNA aptamers specific for Hodgkin lymphoma.
Sensors (Basel)
PUBLISHED: 08-29-2013
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As a "chemical antibody", oligonucleotide aptamers can specifically bind to their target molecules. However, clinical potential of aptamers in disease diagnosis is not yet fully explored. Using a tumor cell-based selection protocol, we developed single-stranded DNA aptamers for Hodgkin lymphoma (HL) tumor cells. The aptamers specifically bound to HL cells with a high affinity, reaching maximal cell binding at 10 nM final concentration. Importantly, the aptamers were able to selectively detect HL cells and did not react to other tumor or blood cells in mixed samples, indicating that the aptamers can be used as a specific probe for in vitro analysis of HL cells. Moreover, due to the inherent properties of DNA, the aptamers were stable in human serum, suggesting potential for in vivo detection of HL tumor cells.
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Synthesis of porous carbon supported palladium nanoparticle catalysts by atomic layer deposition: application for rechargeable lithium-O2 battery.
Nano Lett.
PUBLISHED: 08-14-2013
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In this study, atomic layer deposition (ALD) was used to deposit nanostructured palladium on porous carbon as the cathode material for Li-O2 cells. Scanning transmission electron microscopy showed discrete crystalline nanoparticles decorating the surface of the porous carbon support, where the size could be controlled in the range of 2-8 nm and depended on the number of Pd ALD cycles performed. X-ray absorption spectroscopy at the Pd K-edge revealed that the carbon supported Pd existed in a mixed phase of metallic palladium and palladium oxide. The conformality of ALD allowed us to uniformly disperse the Pd catalyst onto the carbon support while preserving the initial porous structure. As a result, the charging and discharging performance of the oxygen cathode in a Li-O2 cell was improved. Our results suggest that ALD is a promising technique for tailoring the surface composition and structure of nanoporous supports in energy storage devices.
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Preparation of reduced graphene oxide/poly(acrylamide) nanocomposite and its adsorption of Pb(II) and methylene blue.
Langmuir
PUBLISHED: 08-13-2013
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Carboxyl groups at the periphery of reduced graphene oxide (RGO) sheets are converted to amine groups by reaction with N-hydroxysuccinimide and 1,3-diaminopropane, and a free-radical polymerization initiator is anchored to the RGO sheets. Poly(acrylamide) (PAM) polymer brushes on RGO sheets (RGO/PAM) are synthesized by in situ free-radical polymerization. The heavy metals, Pb(II), and the benzenoid compounds, methylene blue, (MB) were selected and adsorbed by RGO/PAM composites, and the adsorption capacity of RGO/PAM for Pb(II) and MB was measured. The experimental data of RGO/PAM isotherms for Pb(II) and MB followed the Langmuir isotherm model. The RGO/PAM displays adsorption capacities as high as 1000 and 1530 mg/g for Pb(II) and MB, respectively, indicating RGO/PAM is a good adsorbent for the adsorption of Pb(II) and MB. The adsorption kinetics of Pb(II) and MB onto RGO/PAM can be well fitted to the pseudo-second-order model. The adsorption processes of Pb(II) and MB onto RGO/PAM are spontaneous at 298, 308, and 318 K.
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Synthesis-dependent atomic surface structures of oxide nanoparticles.
Phys. Rev. Lett.
PUBLISHED: 05-10-2013
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Using SrTiO3 nanocuboids as a model system, we show with aberration-corrected high resolution electron microscopy at sub-Å resolution that surface relaxations or reconstructions are present on the nanocuboids, depending on the synthetic process. Oleic acid synthesis, acetic acid synthesis, and microwave-assisted acetic acid synthesis result in a SrO termination, TiO2-rich reconstruction, and mixed termination, respectively. The experimental atomic positions are in better agreement with density functional theory calculations using an exact-exchange corrected PBEsol functional than the Perdew-Burke-Ernzerhof (PBE) functional.
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Lack of association between vitamin D receptor gene FokI and BsmI polymorphisms and prostate cancer risk: an updated meta-analysis involving 21,756 subjects.
Tumour Biol.
PUBLISHED: 05-01-2013
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The vitamin D receptor (VDR) is a crucial mediator for the cellular effects of vitamin D. The polymorphisms in the VDR gene have been hypothesized to alter the risk of prostate cancer. However, studies investigating the association between VDR polymorphisms (BsmI and FokI) and prostate cancer (PCa) risk report conflicting results , therefore, we conducted a meta-analysis to re-examine the controversy. Published literatures from PubMed, Embase, Google Scholar, and China National Knowledge Infrastructure (CNKI) were searched (updated to March 9, 2013). According to our inclusion criteria, studies that observed the association between VDR BsmI and FokI polymorphisms and PCa risk were included. The principal outcome measure was the odds ratio (OR) with 95 % confidence interval (CI) for PCa risk associated with VDR BsmI and FokI polymorphisms. Thirty-four studies involving 10,267 cases and 11,489 controls were recruited. Overall, we did not find evidence to support an association between any of the VDR polymorphisms and PCa risk. For BsmI, the pooled OR was 0.894 (95 % CI 0.773 to 1.034) for the Bb vs. bb genotypes, 1.002 (95 % CI 0.869 to 1.157) for the BB vs. bb genotypes, 0.922 (95 % CI 0.798 to 1.065) for the dominant model (BB/Bb vs. bb), and 1.018 (95 % CI 0.936 to 1.107) for the recessive model (BB vs. Bb/bb). ORs for the FokI polymorphisms were similar. The results suggest that the VDR BsmI and FokI polymorphisms are not related to PCa risk. Further large and well-designed studies are required to confirm this conclusion.
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A nanostructured cathode architecture for low charge overpotential in lithium-oxygen batteries.
Nat Commun
PUBLISHED: 04-23-2013
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The lithium-oxygen battery, of much interest because of its very high-energy density, presents many challenges, one of which is a high-charge overpotential that results in large inefficiencies. Here we report a cathode architecture based on nanoscale components that results in a dramatic reduction in charge overpotential to ~0.2?V. The cathode utilizes atomic layer deposition of palladium nanoparticles on a carbon surface with an alumina coating for passivation of carbon defect sites. The low charge potential is enabled by the combination of palladium nanoparticles attached to the carbon cathode surface, a nanocrystalline form of lithium peroxide with grain boundaries, and the alumina coating preventing electrolyte decomposition on carbon. High-resolution transmission electron microscopy provides evidence for the nanocrystalline form of lithium peroxide. The new cathode material architecture provides the basis for future development of lithium-oxygen cathode materials that can be used to improve the efficiency and to extend cycle life.
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High-index facets in gold nanocrystals elucidated by coherent electron diffraction.
Nano Lett.
PUBLISHED: 03-18-2013
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Characterization of high-index facets in noble metal nanocrystals for plasmonics and catalysis has been a challenge due to their small sizes and complex shapes. Here, we present an approach to determine the high-index facets of nanocrystals using streaked Bragg reflections in coherent electron diffraction patterns, and provide a comparison of high-index facets on unusual nanostructures such as trisoctahedra. We report new high-index facets in trisoctahedra and previous unappreciated diversity in facet sharpness.
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Discovering transcription and splicing networks in myelodysplastic syndromes.
PLoS ONE
PUBLISHED: 01-01-2013
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More and more transcription factors and their motifs have been reported and linked to specific gene expression levels. However, focusing only on transcription is not sufficient for mechanism research. Most genes, especially in eukaryotes, are alternatively spliced to different isoforms. Some of these isoforms increase the biodiversity of proteins. From this viewpoint, transcription and splicing are two of important mechanisms to modulate expression levels of isoforms. To integrate these two kinds of regulation, we built a linear regression model to select a subset of transcription factors and splicing factors for each co-expressed isoforms using least-angle regression approach. Then, we applied this method to investigate the mechanism of myelodysplastic syndromes (MDS), a precursor lesion of acute myeloid leukemia. Results suggested that expression levels of most isoforms were regulated by a set of selected regulatory factors. Some of the detected factors, such as EGR1 and STAT family, are highly correlated with progression of MDS. We discovered that the splicing factor SRSF11 experienced alternative splicing switch, and in turn induced different amino acid sequences between MDS and controls. This splicing switch causes two different splicing mechanisms. Polymerase Chain Reaction experiments also confirmed that one of its isoforms was over-expressed in MDS. We analyzed the regulatory networks constructed from the co-expressed isoforms and their regulatory factors in MDS. Many of these networks were enriched in the herpes simplex infection pathway which involves many splicing factors, and pathways in cancers and acute or chronic myeloid leukemia.
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Hierarchical nanomorphologies promote exciton dissociation in polymer/fullerene bulk heterojunction solar cells.
Nano Lett.
PUBLISHED: 08-10-2011
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PTB7 semiconducting copolymer comprising thieno[3,4-b]thiophene and benzodithiophene alternating repeat units set a historic record of solar energy conversion efficiency (7.4%) in polymer/fullerene bulk heterojunction solar cells. To further improve solar cell performance, a thorough understanding of structure-property relationships associated with PTB7/fullerene and related organic photovoltaic (OPV) devices is crucial. Traditionally, OPV active layers are viewed as an interpenetrating network of pure polymers and fullerenes with discrete interfaces. Here we show that the active layer of PTB7/fullerene OPV devices in fact involves hierarchical nanomorphologies ranging from several nanometers of crystallites to tens of nanometers of nanocrystallite aggregates in PTB7-rich and fullerene-rich domains, themselves hundreds of nanometers in size. These hierarchical nanomorphologies are coupled to significantly enhanced exciton dissociation, which consequently contribute to photocurrent, indicating that the nanostructural characteristics at multiple length scales is one of the key factors determining the performance of PTB7 copolymer, and likely most polymer/fullerene systems, in OPV devices.
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NSMAP: a method for spliced isoforms identification and quantification from RNA-Seq.
BMC Bioinformatics
PUBLISHED: 05-16-2011
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The development of techniques for sequencing the messenger RNA (RNA-Seq) enables it to study the biological mechanisms such as alternative splicing and gene expression regulation more deeply and accurately. Most existing methods employ RNA-Seq to quantify the expression levels of already annotated isoforms from the reference genome. However, the current reference genome is very incomplete due to the complexity of the transcriptome which hiders the comprehensive investigation of transcriptome using RNA-Seq. Novel study on isoform inference and estimation purely from RNA-Seq without annotation information is desirable.
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Age-related changes in expression in renal AQPs in response to congenital, partial, unilateral ureteral obstruction in rats.
Pediatr. Nephrol.
PUBLISHED: 03-09-2011
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Previously we demonstrated that neonatally induced partial unilateral ureteral obstruction (PUUO) in rats is associated with changes in the abundance of renal acid-base transporters that were paralleled by reduction in renal functions dependent on the severity and duration of obstruction. The aim of the present study was to identify whether changes in renal aquaporin abundance are age-dependent. Semiquantitative immunoblotting and immunohistochemistry were used to examine the changes in abundance of AQP1, AQP2, p-S256AQP2 (AQP2 phosphorylated at consensus site Ser(256)) and AQP3 in the kidneys of rats with neonatally induced PUUO within the first 48 h of life, and then monitored for 7 or 14 weeks. Protein abundance of AQP2 and AQP3 increased in both obstructed and non-obstructed kidneys 7 weeks after induction of neonatal PUUO (PUUO-7W). In contrast, AQP1 and AQP2 protein abundance in the obstructed kidney were reduced after 14 weeks of PUUO (PUUO-14W). Importantly, pS256-AQP2 protein abundance was reduced in obstructed kidneys of both PUUO-7W and PUUO-14W. Immunohistochemistry confirmed the persistent pS256-AQP2 downregulation in both PUUO-7W and PUUO-14W rats. The study shows that the protein abundance of AQP1, AQP2, and AQP3 in the obstructed kidney is increased in PUUO-7W, which may be a compensatory phenomenon and reduced in PUUO-14W rats suggesting a time-/age-dependent dysregulation in response to PUUO. pS256-AQP2 protein abundance is reduced consistent with obstruction-induced direct effects in the apical part of the collecting duct principal cells in response to PUUO.
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Integrative analysis of next generation sequencing for small non-coding RNAs and transcriptional regulation in Myelodysplastic Syndromes.
BMC Med Genomics
PUBLISHED: 02-23-2011
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Myelodysplastic Syndromes (MDSS) are pre-leukemic disorders with increasing incident rates worldwide, but very limited treatment options. Little is known about small regulatory RNAs and how they contribute to pathogenesis, progression and transcriptome changes in MDS.
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Drug inhibition profile prediction for NF?B pathway in multiple myeloma.
PLoS ONE
PUBLISHED: 02-08-2011
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Nuclear factor ?B (NF?B) activation plays a crucial role in anti-apoptotic responses in response to the apoptotic signaling during tumor necrosis factor (TNF?) stimulation in Multiple Myeloma (MM). Although several drugs have been found effective for the treatment of MM by mainly inhibiting NF?B pathway, there are not any quantitative or qualitative results of comparison assessment on inhibition effect between different drugs either used alone or in combinations. Computational modeling is becoming increasingly indispensable for applied biological research mainly because it can provide strong quantitative predicting power. In this study, a novel computational pathway modeling approach is employed to comparably assess the inhibition effects of specific drugs used alone or in combinations on the NF?B pathway in MM and to predict the potential synergistic drug combinations.
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Selective gene transfection of individual cells in vitro with plasmonic nanobubbles.
J Control Release
PUBLISHED: 01-05-2011
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Gene delivery and transfection of eukaryotic cells are widely used for research and for developing gene cell therapy. However, the existing methods lack selectivity, efficacy and safety when heterogeneous cell systems must be treated. We report a new method that employs plasmonic nanobubbles (PNBs) for delivery and transfection. A PNB is a novel, tunable cellular agent with a dual mechanical and optical action due to the formation of the vapor nanobubble around a transiently heated gold nanoparticle upon its exposure to a laser pulse. PNBs enabled the mechanical injection of the extracellular cDNA plasmid into the cytoplasm of individual target living cells, cultured leukemia cells and human CD34+ CD117+ stem cells and expression of a green fluorescent protein (GFP) in those cells. PNB generation and lifetime correlated with the expression of green fluorescent protein in PNB-treated cells. Optical scattering by PNBs additionally provided the detection of the target cells and the guidance of cDNA injection at single cell level. In both cell models PNBs demonstrated a gene transfection effect in a single pulse treatment with high selectivity, efficacy and safety. Thus, PNBs provided targeted gene delivery at the single cell level in a single pulse procedure that can be used for safe and effective gene therapy.
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Luteinizing Hormone-Releasing Hormone (LHRH)-I antagonist cetrorelix inhibits myeloma cell growth in vitro and in vivo.
Mol. Cancer Ther.
PUBLISHED: 11-09-2010
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The objective of this study was to determine the effects of an luteinizing hormone-releasing hormone (LHRH)-I antagonist, Cetrorelix, on human multiple myeloma (MM) cells and to elucidate the mechanisms of action. We showed that LHRH-I and LHRHR-I genes were expressed in MM cell lines and primary MM cells. Treatment with Cetrorelix inhibited growth and colony-forming ability of myeloma cells, including cell lines resistant to arsenic trioxide, bortezomib, or lenalidomide. Cetrorelix induced apoptosis in myeloma cells including primary myeloma cells. In addition, Cetrorelix inhibited the growth of human myeloma cells xenografted into mice without any apparent side effects. Cetrorelix downregulated the nuclear factor-kappa B (NF-?B) pathway activity and the expression of cytokines, including interleukin 6, insulin-like growth factor 1, VEGF-A, and stromal-derived factor 1, important for myeloma cell growth and survival in myeloma cells and/or marrow stromal cells from myeloma patients. Cetrorelix decreased the phosphorylation of extracellular signal regulated kinase 1/2 and STAT3 in myeloma cells, two crucial pathways for myeloma cells growth and survival. Moreover, the expression of p21 and p53 was increased, whereas that of antiapoptotic proteins Bcl-2 and Bcl-x(L) was reduced by Cetrorelix. Our findings indicate that Cetrorelix induces cytotoxicity in myeloma cells through various mechanisms and provide a rationale for investigating Cetrorelix for the treatment of MM.
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Induction of Krüppel-like factor 4 by high-density lipoproteins promotes the expression of scavenger receptor class B type I.
FEBS J.
PUBLISHED: 08-16-2010
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Krüppel-like factor 4 (KLF4) is an evolutionarily conserved zinc finger-containing transcription factor. In the present study, peripheral blood mononuclear cells and phorbol 12-myristate 13-acetate-differentiated THP-1 cells were treated with oxidized low-density lipoproteins and high-density lipoproteins to determine the expression of KLF4 and scavenger receptor class B type I (SR-BI). A full-length cDNA of KLF4 or short interference RNA against KLF4 was transfected into THP-1 cells, and the subsequent expressions of SR-BI were analysed by real-time PCR and western blot. The binding and transcriptional activities of KLF4 to the SR-BI promoter were detected by electrophoretic mobility shift assay, chromatin immunoprecipitation assay and luciferase reporter assay. The results showed that induction of KLF4 by high-density lipoproteins could promote the expression of SR-BI, resulting from the binding to putative KLF4 binding element on the promoter of SR-BI. All results indicate a potential function of KLF4 in the pathogenesis of atherosclerosis through the regulation effect on atherosclerotic-related genes.
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In-phase coupled single-mode gain waveguide array laser.
Opt Lett
PUBLISHED: 07-17-2010
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We utilize a sliced slab waveguide structure to produce a gain waveguide array. With this array, an in-phase locked single-mode frequency output with a single-peak intensity distribution without sidelobes and a highly spatially suppressed far-field distribution has been obtained.
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On the origin of increased phonon scattering in nanostructured PbTe based thermoelectric materials.
J. Am. Chem. Soc.
PUBLISHED: 06-08-2010
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We have investigated the possible mechanisms of phonon scattering by nanostructures and defects in PbTe-X (X = 2% Sb, Bi, or Pb) thermoelectric materials systems. We find that among these three compositions, PbTe-2% Sb has the lowest lattice thermal conductivity and exhibits a larger strain and notably more misfit dislocations at the precipitate/PbTe interfaces than the other two compositions. In the PbTe-Bi 2% sample, we infer some weaker phonon scattering BiTe precipitates, in addition to the abundant Bi nanostructures. In the PbTe-Pb 2% sample, we also find that pure Pb nanoparticles exhibit stronger phonon scattering than nanostructures with Te vacancies. Within the accepted error range, the theoretical calculations of the lattice thermal conductivity in the three systems are in close agreement with the experimental measurements, highlighting the important role of misfit dislocations, nanoscale particles, and associated interfacial elastic strain play in phonon scattering. We further propose that such particle-induced local elastic perturbations interfere with the phonon propagation pathway, thereby contributing to further reduction in lattice thermal conductivity, and consequently can enhance the overall thermoelectric figure of merit.
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The formation and utility of sub-angstrom to nanometer-sized electron probes in the aberration-corrected transmission electron microscope at the University of Illinois.
Microsc. Microanal.
PUBLISHED: 02-26-2010
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We evaluate the probe forming capability of a JEOL 2200FS transmission electron microscope equipped with a spherical aberration (Cs) probe corrector. The achievement of a real space sub-Angstrom (0.1 nm) probe for scanning transmission electron microscopy (STEM) imaging is demonstrated by acquisition and modeling of high-angle annular dark-field STEM images. We show that by optimizing the illumination system, large probe currents and large collection angles for electron energy loss spectroscopy (EELS) can be combined to yield EELS fine structure data spatially resolved to the atomic scale. We demonstrate the probe forming flexibility provided by the additional lenses in the probe corrector in several ways, including the formation of nanometer-sized parallel beams for nanoarea electron diffraction, and the formation of focused probes for convergent beam electron diffraction with a range of convergence angles. The different probes that can be formed using the probe corrected STEM opens up new applications for electron microscopy and diffraction.
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Bone marrow stromal cells from myeloma patients support the growth of myeloma stem cells.
Stem Cells Dev.
PUBLISHED: 02-04-2010
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It has been well documented that bone marrow stromal cells (BMSCs) of multiple myeloma patients play a pivotal role in supporting the growth of mature myeloma cells. With evolving concepts concerning the presence of myeloma stem (initiating) cells, we aimed this investigation to specifically address the supportive role of BMSCs for myeloma stem cell growth in vitro and in vivo. BMSC lines were derived from myeloma or control patients (myeloma or control BMSCs). Myeloma stem cells of the RPMI 8226 myeloma cell line were recognized through the identification of "side populations" (SP) with Hoechst dye staining. SP cells formed more colonies when grown on myeloma BMSC than on control BMSC. Additionally, higher percentages of SP cells were observed when grown on myeloma BMSCs than on control BMSCs. In the mouse model, SP cells inoculated with myeloma BMSCs grew faster than those inoculated with control BMSCs. Of note, SP cells demonstrated an increased expression of CD184 (CXCR4) compared with non-SP cells. The expression of CD184 in SP cells was further increased when they were cultured with myeloma BMSCs. CD184(+) SP cells formed more colonies than CD184(-) SP cells. Treatment with AMD 3100, an inhibitor of CD184, reduced colony formation by CD184(+) SP cells when co-cultured with myeloma BMSCs. This was associated with the decreased activation of ERK, a downstream target of activated CD184, in myeloma cells. These findings indicate that the myeloma BMSCs create a microenvironment supportive of myeloma stem cells via, at least partially, the CXCR4 signaling pathway.
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Unique biomechanical interactions between myeloma cells and bone marrow stroma cells.
Prog. Biophys. Mol. Biol.
PUBLISHED: 10-01-2009
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We observed that BMSCs (bone marrow stromal cells) from myeloma patients (myeloma BMSCs) were significantly stiffer than control BMSCs using a cytocompression device. The stiffness of myeloma BMSCs and control BMSCs was further increased upon priming by myeloma cells. Additionally, myeloma cells became stiffer when primed by myeloma BMSCs. The focal adhesion kinase activity of myeloma cells was increased when cells were on stiffer collagen gels and on myeloma BMSCs. This change in myeloma stiffness is associated with increased colony formation of myeloma cells and FAK activation when co-cultured with stiffer myeloma BMSCs or stiffer collagen. Additionally, stem cells of RPMI8226 cells became stiffer after priming by myeloma BMSCs, with concomitant increases of stem cell colony formation. These results suggest the presence of a mechanotransduction loop between myeloma cells and myeloma BMSCs to increase the stiffness of both types of cells via FAK activation. The increase of stiffness may in turn support the growth of myeloma cells and myeloma stem cells.
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Multiple distinct clones may co-exist in different lineages in myelodysplastic syndromes.
Leuk. Res.
PUBLISHED: 04-28-2009
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Using single nucleotide polymorphism (SNP) microarray with unfractionized bone marrow specimens, recent studies have demonstrated that multiple cytogenetically cryptic genomic aberrations, uniparental disomy (UPD) and/or copy number (CN) aberration, are present in patients with myelodysplastic syndromes (MDS). We hypothesize that various hematopoietic lineages in MDS may carry different cytogenetically cryptic genomic aberrations leading to lineage-specific manifestations of MDS. Flow cytometry sorting was performed to sort 12 MDS marrow samples into blastic, erythroid, immature myeloid and lymphoid fractions. The fractions with enough DNA underwent 250K SNP microarray analysis. Of importance, different chromosomal regions of UPD, deletions and/or gains were present in different fractions of same patients in all samples. Only small percentages (6.7%) of genomic aberrations were present in all fractions from same patients. These results suggest that multiple distinct clones may co-exist in different lineages in MDS and may contribute to cytopenias in specific lineages and the significant clinical heterogeneity observed in these patients. Further studies are warranted to confirm our findings and to investigate the lineage specific genomic lesions in MDS.
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Age-dependent renal expression of acid-base transporters in neonatal ureter obstruction.
Pediatr. Nephrol.
PUBLISHED: 03-27-2009
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Congenital obstructive nephropathy accounts for a major proportion of renal insufficiency in infancy and childhood. In an earlier investigation we demonstrated that bilateral complete ureteral obstruction (BUO) in rats is associated with inadequate urinary acidification [Am J Physiol Renal Physiol. 295(2):F497-506, 2008]. The aim of the study reported here was to determine whether this defect is also associated with unilateral ureteral obstruction (UUO), which is clinically more common than BUO. The time-course of the changes in protein expression levels of major renal acid-base transporters was examined at 7 and 14 weeks in rats with neonatally induced partial unilateral ureteral obstruction (PUUO), which was performed within the first 48 h of life. We observed that protein expression of the renal acid-base transporters NHE3, NBC1, NBCn1, pendrin and Na(+)-K(+)-ATPase was increased in both obstructed and non-obstructed kidneys 7 weeks after the induction of neonatal PUUO. This was confirmed by immunocytochemistry. In contrast, 14 weeks after the induction of PUUO, there was a significant downregulation of the renal acid-base transporters NBC1, NBCn1 and Na(+)-K(+)-ATPase in the obstructed kidneys. These time/age-dependent changes in protein expression were associated with parallel changes in renal function resulting in urine acidification in response to exogenous acid loading. In conclusion, these results show that downregulation of protein expression is a time/age-dependent response to PUUO, which could contribute to the decreased net acid excretion and development of metabolic acidosis in neonatal rats with PUUO.
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Unilateral ureteral obstruction alters expression of acid-base transporters in rat kidney.
J. Urol.
PUBLISHED: 02-18-2009
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Unilateral ureteral obstruction is a common clinical problem that is often associated with a urinary acidification defect caused by decreased net H(+) secretion and/or HCO(3)(-) reabsorption. To clarify the molecular mechanisms of these defects we examined expression levels of key acid-base transporters along the renal nephron segments and collecting duct.
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Expression of transcription factor Oct4 in bladder cancer cell line T24 and its effects on the biological characteristics of the cells.
J. Huazhong Univ. Sci. Technol. Med. Sci.
PUBLISHED: 02-18-2009
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The expression of octamer binding factor 4 (Oct4) gene in bladder cancer cell line T24 and its effects on the biological characteristics of the cells were investigated. RT-PCR and Western blot were employed to detect the expression of Oct4 in T24 cells. The changes of biological characteristics in T24 cells were analyzed before and after gene-silencing by Boyden chamber and MTT. The results showed that the expression of Oct4 gene was detectable in T24 cells by RT-PCR and Western blot. The expression of Oct4 gene and protein was down-regulated by siRNA, and average number of transwell cells in interference group, negative control group and blank control group was 101.40+/-4.56, 104.20+/-10.03 and 111.00+/-11.90, respectively. There was significant difference in the proliferation ability of the cells from 48 h, 72 h to 96 h after the interference by siRNA between interference group and negative group or blank control group (P<0.05). It was suggested that Oct4 gene was related with proliferation ability of T24 cells, but not with invasive capability.
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Enhanced antimyeloma cytotoxicity by the combination of arsenic trioxide and bortezomib is further potentiated by p38 MAPK inhibition.
Leuk. Res.
PUBLISHED: 02-05-2009
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The combination of ATO and bortezomib (ATO+bortezomib) has been recently shown to enhance antimyeloma activity; nevertheless, the mechanisms remained unclear in these studies. However, both bortezomib and ATO have been shown to activate the p38 MAPK pathway, which may counteract the enhancement induced by this combination. We studied the cytotoxicity of bortezomib, ATO, and ATO+bortezomib with or without inhibiting p38 MAPK, along with associated molecular changes in myeloma cells. The treatment of myeloma cells with ATO+bortezomib induced higher cytotoxicity than either agent alone. This increased cytotoxicity was further synergistically enhanced by inhibiting p38 MAPK. This effect was preserved in the presence of marrow stromal cells designed to simulate the tumor micro-environment and in the CD138+ neoplastic plasma cells directly isolated from myeloma patients. The enhanced cytotoxicity of ATO+bortezomib was associated with augmented STAT3 inhibition and JNK activation, up-regulation of Bim, p21, p27, p53 as well as down-regulation of Bcl-2. Furthermore, the synergistically potentiated apoptosis by p38 MAPK inhibition was associated with the attenuation of ATO+bortezomib-mediated activation of Hsp27 as well as the enhancement of ATO+bortezomib-mediated JNK activation, p53 up-regulation, and Bcl-2 down-regulation. The results suggest the opportunity for using p38 MAPK inhibition to enhance the efficacy of ATO+bortezomib in myeloma.
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p38 Mitogen-activated protein kinase and hematologic malignancies.
Arch. Pathol. Lab. Med.
PUBLISHED: 01-13-2009
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p38 mitogen-activated protein kinase (MAPK) signaling has been implicated in responses ranging from apoptosis to cell cycle, induction of expression of cytokine genes, and differentiation. This plethora of activators conveys the complexity of the p38 pathway. This complexity is further complicated by the observation that the downstream effects of p38 MAPK activation may be different depending on types of stimuli, cell types, and various p38 MAPK isoforms involved.
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Phenotyping studies of clonotypic B lymphocytes from patients with multiple myeloma by flow cytometry.
Arch. Pathol. Lab. Med.
PUBLISHED: 01-06-2009
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Clonotypic B lymphocytes, monoclonal B lymphocytes sharing identical, rearranged IGH-CDR3 sequences with the patients myeloma cells, have been detected in the peripheral blood of patients with multiple myeloma. These cells have been postulated to act as a therapy-resistant tumor reservoir that drives recurrence.
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Construction of a novel oncolytic adenoviral vector and its biological characteristics.
Oncol. Rep.
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In this study, we aimed to construct an effective and safe oncolytic adenoviral vector for cancer treatment with gene therapy. First, the promoter of the catalytic subunit of human telomerase (hTERTp), adenovirus early region 1a gene (E1A) and thymidine kinase gene of human herpes virus type 1 (HSV-1-TK) were amplified by using PCR from genomic DNA of 293A cells and wild-type HSV-1 (wHSV-1). These specially-prepared elements were inserted into an adenoviral shuttle vector in the opposite and the same directions of left inverted terminal repeat (L-ITR), respectively, to construct pENTR-E1A-IRES-TK-hTERTp (pEITH) and pENTR-hTERTp-E1A-IRES-TK (pHEIT). LR reaction between adenoviral shuttle vectors (pEITH and pHEIT) and the backbone vector DEST was carried out to establish adenoviral expression vectors pAd-E1A-IRES-TK-hTERTp (pAd-EITH) and pAd-hTERTp-E1A-IRES-TK (pAd-HEIT). Recombinant adenovirus Ad-EITH and Ad-HEIT were produced by transfecting 293A cells and purified for the subsequent studies of titer measurement, replication capability with and without acyclovir (ACV) and antitumor ability with and without ganciclovir (GCV) to evaluate the biological characteristics. Adenoviral shuttle vectors pEITH and pHEIT and expression vectors pAd-EITH and pAd-HEIT were successfully constructed, and recombinant adenoviruses Ad-EITH and Ad-HEIT with high titer were produced. The results of replication and cytotoxicity assays showed that Ad-EITH and Ad-HEIT replicated in the hTERTp (+) human nasopharyngeal carcinoma cell line CNE and expressed the TK gene effectively leading to the death of tumor cells. In addition, there were still some Ad-HEIT particles replicating in the hTERTp (-) human osteosarcoma U-2OS cells and human lung HFL-1 fibroblasts compared to Ad-EITH which was hardly able to replicate in U-2OS and HFL-1 cells. In addition, we also observed an interesting phenomenon, that the replication of Ad-EITH could be inhibited by antiviral drug ACV on account of the expression of HSV-1-TK gene making Ad-EITH sensitive to ACV. In conclusion, a novel oncolytic adenoviral vector Ad-EITH was produced which can be used for cancer-specific and efficient viral replication, and its safety is potentially improved as replication can be inhibited by ACV in vitro.
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Cancer stem cells: a review of potential clinical applications.
Arch. Pathol. Lab. Med.
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Cancer stem cells (CSCs) comprise a minor cell population in a tumor; however, they possess self-renewal capacity and are responsible for tumor recurrence and the emerging issue of tumor resistance. Despite recent advances in the study of pathogenesis and mechanisms of CSC-mediated disease recurrence and multidrug resistance, many questions remain unanswered.
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In situ wet-cell TEM observation of gold nanoparticle motion in an aqueous solution.
Nanoscale Res Lett
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In situ wet-cell transmission electron microscopy (TEM) technology enables direct observation of nanomaterials in a fully hydrated environment with high spatial and temporal resolution, which can be used to address a wide range of scientific problems. In this paper, the motions of approximately 5-nm sized gold nanoparticles in an aqueous solution are studied using the wet-cell TEM technology. It is observed that gold nanoparticles can be either in a single particle or cluster forms, and dynamic displacement and rotation motions are observed for both forms in the solution. Under electron beam irradiation, nanoparticles in some clusters gradually fused together; sometimes they also showed dramatic growth behavior. Mechanisms for the motion and growth of the particles/clusters are discussed.
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Vacuum-deposited small-molecule organic solar cells with high power conversion efficiencies by judicious molecular design and device optimization.
J. Am. Chem. Soc.
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Three new tailor-made molecules (DPDCTB, DPDCPB, and DTDCPB) were strategically designed and convergently synthesized as donor materials for small-molecule organic solar cells. These compounds possess a donor-acceptor-acceptor molecular architecture, in which various electron-donating moieties are connected to an electron-withdrawing dicyanovinylene moiety through another electron-accepting 2,1,3-benzothiadiazole block. The molecular structures and crystal packings of DTDCPB and the previously reported DTDCTB were characterized by single-crystal X-ray crystallography. Photophysical and electrochemical properties as well as energy levels of this series of donor molecules were thoroughly investigated, affording clear structure-property relationships. By delicate manipulation of the trade-off between the photovoltage and the photocurrent via molecular structure engineering together with device optimizations, which included fine-tuning the layer thicknesses and the donor:acceptor blended ratio in the bulk heterojunction layer, vacuum-deposited hybrid planar-mixed heterojunction devices utilizing DTDCPB as the donor and C(70) as the acceptor showed the best performance with a power conversion efficiency (PCE) of 6.6 ± 0.2% (the highest PCE of 6.8%), along with an open-circuit voltage (V(oc)) of 0.93 ± 0.02 V, a short-circuit current density (J(sc)) of 13.48 ± 0.27 mA/cm(2), and a fill factor (FF) of 0.53 ± 0.02, under 1 sun (100 mW/cm(2)) AM 1.5G simulated solar illumination.
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Ambient-stable tetragonal phase in silver nanostructures.
Nat Commun
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Crystallization of noble metal atoms usually leads to the highly symmetric face-centred cubic phase that represents the thermodynamically stable structure. Introducing defective microstructures into a metal crystal lattice may induce distortions to form non-face-centered cubic phases when the lateral dimensions of objects decrease down to nanometre scale. However, stable non-face-centered cubic phases have not been reported in noble metal nanoparticles. Here we report that a stable body-centred tetragonal phase is observed in silver nanoparticles with fivefold twinning even at ambient conditions. The body-centered tetragonal phase originates from the distortion of cubic silver lattices due to internal strains in the twinned nanoparticles. The lattice distortion in the centre of such a nanoparticle is larger than that in the surfaces, indicating that the nanoparticle is composed of a highly strained core encapsulated in a less-strained sheath that helps stabilize the strained core.
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Prediction of the outcome of antenatal hydronephrosis: significance of urinary EGF.
Pediatr. Nephrol.
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Down-regulation of epidermal growth factor (EGF) in the renal parenchyma has been demonstrated in children who underwent pyeloplasty due to ureteropelvic junction obstruction (UPJO). Urine levels of EGF were confirmed to parallel this finding before and after surgery. The aim of our study was to evaluate the relationship between urinary EGF (uEGF) concentrations and Society of Fetal Urology (SFU) high-grade hydronephrosis in infants presenting unilateral antenatal hydronephrosis (ANH).
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Self-assembly of a diblock copolymer with pendant disulfide bonds and chromophore groups: a new platform for fast release.
Langmuir
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An amphiphilic block copolymer comprising poly(ethylene glycol) (PEG) and poly(2-(methacryloyl)oxyethyl-2-hydroxyethyl disulfide) (PMAOHD) blocks was synthesized by atom transfer radical polymerization (ATRP). Pyrenebutyric acid was conjugated to the block copolymer by esterification, and a block copolymer with pendant disulfide bonds and pyrenyl groups (PEG-b-P(MAOHD-g-Py)) was obtained. (1)H NMR and gel permeation chromatography (GPC) results demonstrated the successful synthesis of the block copolymer. The cleavage of the disulfide bonds and the degrafting of the pyrenyl groups were investigated in THF and a THF/methanol mixture. Fluorescence spectroscopy, GPC, and (1)H NMR results demonstrated fast cleavage of the disulfide bonds by Bu(3)P in THF. Fluorescence results showed the ratio of the intensity of the excimer peak to the monomer peak decreased rapidly within 20 min. GPC traces of the block copolymer moved to a long retention time region after addition of Bu(3)P, indicating the cleavage of the disulfide bonds and the degrafting of the pyrenyl groups. PEG-b-P(MAOHD-g-Py) can self-assemble into micelles with poly(MAOHD-g-Py) cores and PEG coronae in a mixture of methanol and THF (9:1 by volume). The dissociation of the micelles in the presence of Bu(3)P was investigated. After cleavage of the disulfide bonds in the micellar cores, a pyrene-containing small molecular compound and a block copolymer with pendant thiol groups were produced. Transmission electron microscopy (TEM), dynamic light scattering (DLS), and (1)H NMR were employed to track the dissociation of the polymeric micelles. All the techniques demonstrated the dissociation of the micelles and the fast release of pyrenyl groups from the micelles.
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Urinary heme oxygenase-1 in children with congenital hydronephrosis due to ureteropelvic junction obstruction.
Biomarkers
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Heme oxygenase-1 (HO-1) is implicated to be correlated with renal function in oxidative stress.
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Monitoring the progression of metastatic breast cancer on nanoporous silica chips.
Philos Trans A Math Phys Eng Sci
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Breast cancer accounted for 15 per cent of total cancer deaths in female patients in 2010. Although significant progress has been made in treating early-stage breast cancer patients, there is still no effective therapy targeting late-stage metastatic breast cancers except for the conventional chemotherapy interventions. Until effective therapy for later-stage cancers emerges, the identification of biomarkers for the early detection of tumour metastasis continues to hold the key to successful management of breast cancer therapy. Our study concentrated on the low molecular weight (LMW) region of the serum protein and the information it contains for identifying biomarkers that could reflect the ongoing physiological state of all tissues. Owing to technical difficulties in harvesting LMW species, studying these proteins/peptides has been challenging until now. In our study, we have recently developed nanoporous chip-based technologies to separate small proteins/peptides from the large proteins in serum. We used nanoporous silica chips, with a highly periodic nanostructure and uniform pore size distribution, to isolate LMW proteins and peptides from the serum of nude mice with MDA-MB-231 human breast cancer lung metastasis. By matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and biostatistical analysis, we were able to identify protein signatures unique to different stages of cancer development. The approach and results reported in this study possess a significant potential for the discovery of proteomic biomarkers that may significantly enhance personalized medicine targeted at metastatic breast cancer.
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Differentiating between Burkitt lymphoma and CD10+ diffuse large B-cell lymphoma: the role of commonly used flow cytometry cell markers and the application of a multiparameter scoring system.
Am. J. Clin. Pathol.
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The goal of this study was to evaluate routine flow cytometric (FC) immunophenotypic markers in differentiating between Burkitt lymphoma (BL) and CD10+ diffuse large B-cell lymphoma (DLBCL). We performed retrospective analysis of FC data from 55 patients. We evaluated 9 FC parameters: forward and side scatter (FSC and SSC); mean fluorescent intensity (MFI) for CD20, CD10, CD38, CD79b, CD43, and CD71; and the percentage of neoplastic cells positive for CD71 (%CD71). The FSC; MFIs of CD10, CD43, CD79b, and CD71; and %CD71 cells were significantly different between BL and CD10+ DLBCL (P < .05; Student t test). A 5-point scoring system (FSC, %CD71, and MFIs of CD43, CD79b, and CD71) was devised, and 6 (60%) of 10 BLs scored 3 or greater and 1 (10%) of 10 CD10+ DLBCLs scored 3 (P = .04; ?(2)). Our findings indicate that routine FC parameters can aid in differentiating BL from CD10+ DLBCL.
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A systematic modeling study on the pathogenic role of p38 MAPK activation in myelodysplastic syndromes.
Mol Biosyst
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Myelodysplastic syndromes (MDS) are a group of clonal hematopoietic stem cell diseases. In addition to intrinsic genetic alterations, the effects of the extrinsic microenvironment also play a pathological role in MDS development. The presence of increased inflammatory cytokines, such as tumor necrosis factor-alpha (TNF-?), in marrow and abnormal activation of the p38 mitogen-activated protein kinase (MAPK) signaling pathway in hematopoietic cells are associated with the ineffective hematopoiesis in MDS. However, the molecular mechanism of p38 MAPK activation triggered by microenvironment cytokines remains poorly understood. To address this question, we combined computational modeling analysis and molecular biology studies to perform a systematic investigation of signaling events regulated by microenvironment cytokines in hematopoietic cells from MDS patients. We examined dynamic changes of key signaling events, including the p38 MAPK and the c-Jun N-terminal kinase (JNK) pathway in bone marrow mononuclear cells from MDS patients or normal donors in response to TNF-? stimulation using reverse phase protein array technology. The results were analyzed by a novel computational model and preliminarily validated by immunohistochemistry analysis of the bone marrow tissues from twelve MDS patients and normal donors. Our systematic model revealed that the dynamic response patterns of p38 MAPK and JNK to TNF-? stimulation in MDS were different from that observed in normal marrow cells. Particularly, B-cell lymphoma-X (BCL-XL) protein degradation was regulated by the JNK pathway in normal cells, but by p38 MAPK in MDS cells. By immunohistochemistry, BCL-XL was highly expressed in hematopoietic cells from normal marrow, but was minimally expressed in MDS marrow. Additionally, immunostaining for phosphorylated p38 MAPK? showed much higher p38 MAPK activation in MDS marrows, supporting over-activation of p38 MAPK-enhanced degradation of BCL-XL in MDS. The degradation of BCL-XL triggered by p38 MAPK over-activation may contribute to the increasing apoptosis of marrow cells, a phenomenon commonly observed in MDS, and lead to ineffective hematopoiesis. Our study suggests that the combination of molecular biological studies and systematic modeling is a powerful tool for comprehensive investigation of the complex cellular mechanisms involved in MDS pathogenesis.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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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.