1916 Patterson St Suite 501
Nashville TN 37203
Medical School: Other - 1983
Accepts Medicare: Yes
Participates In eRX: No
Participates In PQRS: No
Participates In EHR: No
License #: MD0000042416
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Dr. Yihan Wang is associated with these group practices
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CellMethy: Identification of a focal concordantly methylated pattern of CpGs revealed wide differences between normal and cancer tissues. - Scientific reports
DNA methylation patterns may serve as a key in determining cell phenotypes and functions. Adjacent CpG patterns may provide insight into methylation functional mechanisms. Some regions display different DNA methylation patterns between normal and cancer tissues, but the same average methylation level. Here, we developed a method (CellMethy) to infer a region in which all CpGs exhibit concordant methylation (CM) and to quantify the extent of CM in the region. Using simulation data, CellMethy showed high performance in discovering the concordant methylation patterns (AUCâ€‰=â€‰0.89). CellMethy was then applied to RRBS data including 11 normal tissues and 12 tumors. We found that the extent of CM exhibited wider differentials among tissues than did the average methylation levels from the CM regions, with 45% of CM regions occurring specifically in one tissue and mainly in tumors. Then, we identified CM regions through genome wide bisulfite sequencing (GWBS) data on breast cancer. Approximately 82% of CM regions revealed a significantly different extent of CM between cancer and normal tissues. CellMethy can accurately describe concordantly methylated regions, and the results suggest that CM might also serve as a stable marker of cell sub-populations.
Secondary neurolymphomatosis of spinal nerve roots detected by (18)F-FDG PET/CT: a case report and differential diagnosis of the case. - Hellenic journal of nuclear medicine
Neurolymphomatosis (NL) is a rare neurological manifestation of lymphoma. Clinical symptoms of NL differ greatly according to the sites involved and diagnosis with conventional imaging techniques may sometimes be difficult. We herein describe the case of a 58 years old man presenting as radiculopathy with a history of non-Hodgkin's lymphoma (NHL). Computed tomography (CT) was unrevealing and magnetic resonance imaging (MRI) was contraindicated. Fluorine-18 fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) was performed and revealed multiple hypermetabolic lesions along the nerve roots, which corresponded to the patient's neurological symptoms. A differential diagnosis of patients with lymphomatous involvement of spinal nerve roots has been presented.Our case suggests that (18)F-FDG PET/CT successfully detected the infiltration of spinal nerve roots of NL due to lymphoma.
Uric acid enhances the antitumor immunity of dendritic cell-based vaccine. - Scientific reports
Uric acid (UA) released from dying cells has been recognized by the immune system as a danger signal. In response to UA, dendritic cells (DC) in the immune system mature and enhance the T cell response to foreign antigens. It is conceivable that the antitumor immunity of a tumor vaccine could be promoted by the administration of UA. To test this concept, we applied UA as an adjuvant to a DC-based vaccine, and discovered that the administration of UA as an adjuvant significantly enhanced the ability of the tumor lysate-pulsed DC vaccine in delaying the tumor growth. The antitumor activity was achieved with adoptively transferred lymphocytes, and both CD8(+) T cells and NK cells were required to achieve effective immunity. This resulted in an increased accumulation of activated CD8(+) T cells and an elevated production of IFN-Î³. Collectively, our study shows that the administration of UA enhances the antitumor activity of tumor lysate-pulsed DC vaccine, thus providing the preclinical rationale for the application of UA in DC-based vaccine strategies.
DNA Methylation Patterns Can Estimate Nonequivalent Outcomes of Breast Cancer with the Same Receptor Subtypes. - PloS one
Breast cancer has various molecular subtypes and displays high heterogeneity. Aberrant DNA methylation is involved in tumor origin, development and progression. Moreover, distinct DNA methylation patterns are associated with specific breast cancer subtypes. We explored DNA methylation patterns in association with gene expression to assess their impact on the prognosis of breast cancer based on Infinium 450K arrays (training set) from The Cancer Genome Atlas (TCGA). The DNA methylation patterns of 12 featured genes that had a high correlation with gene expression were identified through univariate and multivariable Cox proportional hazards models and used to define the methylation risk score (MRS). An improved ability to distinguish the power of the DNA methylation pattern from the 12 featured genes (p = 0.00103) was observed compared with the average methylation levels (p = 0.956) or gene expression (p = 0.909). Furthermore, MRS provided a good prognostic value for breast cancers even when the patients had the same receptor status. We found that ER-, PR- or Her2- samples with high-MRS had the worst 5-year survival rate and overall survival time. An independent test set including 28 patients with death as an outcome was used to test the validity of the MRS of the 12 featured genes; this analysis obtained a prognostic value equivalent to the training set. The predict power was validated through two independent datasets from the GEO database. The DNA methylation pattern is a powerful predictor of breast cancer survival, and can predict outcomes of the same breast cancer molecular subtypes.
The positive effects of Mn(2+) on nitrogen use and surfactin production by Bacillus subtilis ATCC 21332. - Biotechnology, biotechnological equipment
Surfactin, one of the most effective biosurfactants, has great potential in commercial applications. Studies on effective methods to reduce surfactin's production cost are always a hotspot in the research field of biosurfactants. The aim of this study was to reveal the role of Mn(2+) in promoting the biosynthesis of surfactin by Bacillus subtilis ATCC 21332, which could arise more targeted suggestions on surfactin yield promotion. In this study, B. subtilis was cultivated in media containing different Mn(2+) concentrations. The obtained results showed that the yield of surfactin gradually increased upon Mn(2+) addition (0.001 to 0.1 mmol/L) and achieved the maximal production of 1500 mg/L, which reached 6.2-fold of the yield obtained in media without Mn(2+) addition. Correspondingly, the usage ratios of ammonium nitrate were improved. When the Mn(2+) concentration was higher than 0.05 mmol/L, nitrate became the main nitrogen source, instead of ammonium, indicating that the nitrogen utilization pattern was also changed. An increase in nitrate reductase activity was observed and the increase upon Mn(2+) dosage had a positive correlate with nitrate use, and then stimulated secondary metabolic activity and surfactin synthesis. On the other hand, Mn(2+) enhanced the glutamate synthase activity, which increased nitrogen absorption and transformation and provided more free amino acids for surfactin synthesis.
Full time-resolved diffuse fluorescence tomography accelerated with parallelized Fourier-series truncated diffusion approximation. - Journal of biomedical optics
Of the three measurement schemes established for diffuse fluorescence tomography (DFT), the time-domain scheme is well known to provide the richest information about the distribution of the targeting fluorophore in living tissues. However, the explicit use of the full time-resolved data usually leads to a considerably lengthy time for image reconstruction, limiting its applications to three-dimensional or small-volume imaging. To cope with the adversity, we propose herein a computationally efficient scheme for DFT image reconstruction where the time-dependent photon density is expanded to a Fourier-series and calculated by solving the independent frequency-domain diffusion equations at multiple sampling frequencies with the support of a combined multicore CPU-based coarse-grain and multithread GPU-based fine-grain parallelization strategy. With such a parallelized Fourier-series truncated diffusion approximation, both the time- and frequency-domain inversion procedures are developed and validated for their effectiveness and accuracy using simulative and phantom experiments. The results show that the proposed method can generate reconstructions comparable to the explicit time-domain scheme, with significantly reduced computational time.
Chitosan nanofibers fabricated by combined ultrasonic atomization and freeze casting. - Carbohydrate polymers
Aligned chitosan nanofibers exhibiting diameters smaller than 100 nm were easily prepared by combining ultrasonic atomization with freeze casting. A major advantage of this approach is the use of distilled water as main solvent. Scanning electron microscopy demonstrated that fiber diameter and morphology mainly depended on the atomizing tools, freezing temperature, and chitosan solution viscosity. Minimum diameter and uniform orientation were achieved using an electric flosser as an atomizing tool, liquid nitrogen as a coolant, 0.4 wt% aqueous chitosan solution (molecular weight = 22 kDa), and a small amount of lactic acid as solvent at 0 Â°C. The resulting chitosan nanofibers may find application in biomedical and food engineering. Moreover, this new technology may be applicable to other natural and synthetic water-soluble polymers.Copyright Â© 2015 Elsevier Ltd. All rights reserved.
A novel controlled-release system for antibacterial enzyme lysostaphin delivery using hydroxyapatite/chitosan composite bone cement. - PloS one
In this work, a lysostaphin-loaded, control-released, self-setting and injectable porous bone cement with efficient protein delivery was prepared by a novel setting method using hydroxyapatite/chitosan (HA/CS) composite scaffold. The cement samples were made through cementitious reactions by mixing solid powder, a mixture of HA/CS composite particles, lysostaphin, Ca(OH)2, CaCO3 and NaHCO3, with setting liquid containing citric acid, acetic acid, NaH2PO4, CaCl2 and poloxamer. The setting parameters of the cement samples were determined. The results showed that the final setting time was 96.6Â±5.2 min and the pH value increased from approximately 6.2 to nearly 10 during the setting process and the porosity was 34% at the end. And the microstructure and composition were detected by scanning electron microscopy (SEM), x-ray diffraction and Fourier transform-infrared spectroscopy. For the release behavior of lysostaphin loaded in the cement sample, the in vitro cement extract experiment indicated that about 94.2Â±10.9% of the loaded protein was released before day 8 and the in vivo Qdot 625 fluorescence tracking experiment showed that the loaded protein released slower than the free one. Then the biocompatibility of the cement samples was evaluated using the methylthiazol tetrazolium assay, SEM and hematoxylin-eosin staining, which suggested good biocompatibility of cement samples with MC 3T3-E1 cells and subcutaneous tissues of mice. Finally the antibacterial activity assay indicated that the loaded lysostaphin had good release ability and strong antibacterial enzymatic activity against methicillin-resistant Staphylococcus aureus. Collectively, all the results suggested that the lysostaphin-loaded self-setting injectable porous bone cement released the protein in a controlled and effective way and the protein activity was well retained during the setting and releasing process. Thus this bone cement can be potentially applied as a combination of artificial bone substitute and controlled-release system for delivery of lysostaphin to treat bone defects and infections.
Stretched exponential relaxation of piezovoltages in wet bovine bone. - Journal of the mechanical behavior of biomedical materials
It is important to determine the amplitude and variation characteristics of piezovoltage in wet bone, which can, in turn, be taken as a basis for studying whether electrical signals induced by external forces can affect the growth of bone cells. This work measured the characteristics of piezoelectric effects under dynamic and static loading. The results show that the variations of piezovoltage in wet bone in both loading and load holding periods follow a stretched exponential relaxation law, and the relaxation time constants of the piezovoltages are much larger than those of dry bone. This finding means that the active time of piezovoltage in wet bone is much longer than that of dry bone. Regardless of the loading and load holding processes, continuously increasing deformation in wet bone caused piezoelectric charges to be continuously induced and increased the dielectric constant of wet bone along with the deformation process. In general, compared with piezovoltage in dry bone, that in wet bone had lower amplitude and could exist for a longer duration. It can be inferred, therefore, that piezoelectricity might create coupling with the streaming potential in bone by changing the thickness of the double electrode layer.Copyright Â© 2014 Elsevier Ltd. All rights reserved.
Heat shock protein 72 suppresses apoptosis by increasing the stability of X-linked inhibitor of apoptosis protein in renal ischemia/reperfusion injury. - Molecular medicine reports
Xâ€‘linked inhibitor of apoptosis protein (XIAP) negatively regulates apoptotic pathways at a postâ€‘mitochondrial level. XIAP functions by directly binding and inhibiting activation of specific caspases. Upon apoptotic stimuli, mitochondrial second mitochondriaâ€‘derived activator of caspases (Smac)/direct IAPâ€‘binding protein with low PI (Diablo) is released into the cytosol, which results in displacement of XIAP from caspases. Heat shock protein 72 (HSP72), an antiâ€‘apoptotic protein, prevents mitochondrial injury resulting from acute renal ischemia/reperfusion (I/R), its role in Smac/Diablo and XIAP signaling remains to be elucidated. In the present study, the hypothesis that HSP72 prevents XIAP degradation in vivo and in vitro was assessed. To this purpose, a rat model of I/R injury was used to investigate the renoprotective role of HSP72 by treatment with geranylgeranylacetone (GGA), a specific inducer of HSP72. The mechanism of the cytoprotective properties of HSP72 was also investigated in vitro using adenovirusâ€‘mediated overexpression of HSP72 in adenosine triphosphate (ATP)â€‘depleted human kidney 2 (HKâ€‘2) cells. Preâ€‘conditioning rats with GGA attenuated renal tubular cell damage, reduced cell apoptosis, preserved XIAP protein content and improved renal function following I/R injury. An in vitro study was performed in which cells were transiently exposed to 5 mM sodium cyanide in a glucoseâ€‘free medium in order to induce apoptosis. Compared with the control, overexpression of HSP72 inhibited Smac/Diablo release from the mitochondria and increased levels of XIAP and proâ€‘caspase 3 in ATPâ€‘depleted HKâ€‘2 cells. In addition, HSP72 interacted with Smac/Diablo. The present data demonstrates that HSP72 preserves renal function in I/R injury through its antiâ€‘apoptotic effects, which act by suppressing mitochondrial Smac/Diablo release and preserving XIAP protein content.
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