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Biomedical subjects

Hong Tang

Publications and source records attributed to Hong Tang.

At least 37 records · Page 2Linked to original sources
PubMed2005

The host type I interferon response to viral and bacterial infections.

Type I interferons (IFN) are well studied cytokines with anti-viral and immune-modulating functions. Type I IFNs are produced following viral infections, but until recently, the mechanisms of viral recognition leading to IFN production were largely unknown. Toll like receptors (TLRs) have emerged as key transducers of type I IFN during viral infections by recognizing various viral components. Furthermore, much progress has been made in defining the signaling pathways downstream of TLRs for type I IFN production. TLR7 and TLR9 have become apparent as universally important in inducing type I IFN during infection with most viruses, particularly by plasmacytoid dendritic cells. New intracellular viral pattern recognition receptors leading to type I IFN production have been identified. Many bacteria can also induce the up-regulation of these cytokines. Interestingly, recent studies have found a detrimental effect on host cells if type I IFN is produced during infection with the intracellular gram-positive bacterial pathogen, Listeria monocytogenes. This review will discuss the recent advances made in defining the signaling pathways leading to type I IFN production.

Animals↗
PubMed2005

The transcriptional transactivation function of HBx protein is important for its augmentation role in hepatitis B virus replication.

The role and functional domain of hepatitis B virus (HBV) X protein (HBx) in regulating HBV transcription and replication were investigated with a transient transfection system in the human hepatoma cell line HepG2 using wild-type or HBx-minus HBV genome constructs and a series of deletion or mutation HBx expression plasmids. We show here that HBx has augmentation effects on HBV transcription and replication as a HBV mutant genome with defective X gene led to decreased levels of 3.5-kb HBV RNA and HBV replication intermediates and that these decreases can be restored by either transient ectopic expression of HBx or a stable HBx expression cell line. The C-terminal two-thirds (amino acids [aa] 51 to 154), which contain the transactivation domain, is required for this function of HBx; the N-terminal one-third (aa 1 to 50) is not required. Using the alanine scanning mutagenesis strategy, we demonstrated that the regions between aa 52 to 65 and 88 to 154 are important for the augmentation function of HBx in HBV replication. By the luciferase reporter gene analysis, we found that the transactivation and coactivation activities of HBx coincide well with its augmentation function in HBV transcription and replication. These results suggest that HBx has an important role in stimulating HBV transcription and replication and that the transcriptional transactivation function of HBx may be critical for its augmentation effect on HBV replication.

Amino Acid Sequence↗
PubMed2005

[Spectral similarity measure and retrieval based on the complete spectral reflectance and absorption feature--nonlinear spectral angle mapper].

A novel method for spectral similarity measure, which is called nonlinear spectral angle mapper, is presented. In this method, on one hand, nonlinear transformation and removing high relativity among bands are used through kernel PCA; on the other hand, the feature of both spectral reflection and absorption are combined in transformed space. At last, spectral angle mapper is used to measure spectral similarity. The authors' experiments show that this method is effective in spectral similarity retrieval.

Absorption↗
PubMed2005

[Influence of wen-yang herbs on hemodynamics in liver fibrotic rats].

OBJECTIVES: To observe the influence of wen-yang herbs on the hemodynamics in liver fibrotic rats. METHODS: Wistar rats with liver fibrosis, induced by carbon tetrachloride and alcohol, were randomly divided into a treatment group and a control group. The treatment group was administered wen-yang herbs and the control group saline. At the end of the experiment, the hemodynamic markers of the liver and the mesentery, the liver function and hydroxyproline content of liver tissues between the two groups were compared. Blood volume of the livers and hydroxyproline content of liver tissues were also determined. RESULTS: Blood volume of the liver and mesentery (P < 0.01) and blood flow velocity of small vein of mesentery (P < 0.05) of the treatment group were distinctly higher than the control group. The hydroxyproline content (P < 0.01) of the treatment group was remarkably reduced and liver function was improved. CONCLUSION: Wen-yang herbs can activate microcirculation of the liver and mesentery, decrease the deposit of collagen in the liver and improve liver function.

Animals↗
PubMed2005

[A medical ultrasonic image filtering method based on anisotropic diffusion].

OBJECTIVE: To remove the speckle noise in ultrasonic images by using anisotropic diffusion method. METHOD: Based on anisotropic diffusion, a partial differential equation, of which the initial data was the input images, was transformed into differential forms and solved with iterations. The speckle scale function of the equation was modified to make better use in filtering medical ultrasonic images. RESULT: By comparing the results with other three filters, the anisotropic diffusion method could smooth the speckles very well and the edge of the image was also clear. CONCLUSION: Anisotropic diffusion can remove the speckle noise effectively and has great potential in filtering medical ultrasonic images.

Anisotropy↗
PubMed2005

[Differentiation of mouse bone marrow mesenchymal stem cells into hepatocyte in vivo].

To explore the possibility of mouse bone marrow mesenchymal stem cells (BMSCs) differentiating into hepatocyte in vivo, the BMSCs isolated from donor male BALB/C mice at age of 6-8 weeks were transplanted to female BALB/C mice as recipients by transfusion via tail vein or direct liver injection. By the end of 1st, 2nd, 4th weeks after transplantation, the Y chromosome positive and albumin expression positive hepatocytes were detected from the recipient female mouse liver tissue by fluorescence in situ hybridization (FISH ) and immunohistochemistry (IHC). In the two groups of direct liver injection, no matter whether the donor cells are fresh isolated bane marrow cells or passage 3 cells, the Y chromosome positive cells with albumin expression simultaneously were detected by the end of the 1st week after transplantation. Similar result has been observed in the other subgroup of tail vein injection, but only by the end of the 2nd week after transplantation. BMSCs are capable of differentiating into hepatocyte in vivo.

Animals↗
PubMed2005

[Immune response enhanced by genes encoding IFN-alpha 8 and T alpha 1 co-inoculated with HBV DNA vaccine].

OBJECTIVES: To evaluate if the humoral immune response of hepatitis B DNA vaccine pVAX1-S2S could be enhanced by Talpha1 and/or IFNa expression plasmid co-inoculated. METHODS: The following mammalian expression recombinant plasmids were constructed: the plasmid pVAX1-S2S expressing hepatitis B surface antigen S2S, the plasmid pVAX1-T/I co-expressing thymosin a and IFNalpha, the plasmid pVAX1-I/S2S co-expressing IFNalpha and S2S. These plasmids were inoculated intramuscularly into several BALB/c mice groups in different combinations. In the co-immunization group 1 (pVAX1-I/S2S), each mouse was inoculated with 100 microg of pVAX1-I/S2S; in the co-immunization group 2 (pVAX1-S2S) each mouse was co-inoculated with pVAX1-S2S and 50 microg of pVAX1-TI; in the control group each mouse was inoculated with 100 microg of pVAX1-S2S. All the immunizations were boosted at 2 and 4 week intervals; then the serum samples were collected to detect the anti-HBs and anti-preS2 strengths. RESULTS: 3, 5 and 8 weeks after the first inoculation, the positive rates of anti-HBs were 12.5%, 12.5%, 62.5% respectively in the co-immunization group 1 and 25%, 50%, 50% in the co-immunization group 2, while those in the control group were 0, 25%, 37.5%. The titers of anti-preS2 in co-immunization group 2 was 5 times higher than those in the other two groups. CONCLUSION: The data shows that Talpha1 and/or IFNalpha expression plasmid co-inoculated with pVAX1-S2S might act as an adjuvant to enhance the humoral immune response induced by pVAX1-S2S.

Adjuvants, Immunologic↗
PubMed2005

[The protective effects of Radix Astragali and Rhizoma Ligustici chuanxiong on endothelial dysfunction in type 2 diabetic patients with microalbuminuria].

OBJECTIVE: To evaluate the effects of traditional Chinese complex prescription of Radix Astragali and Rhizoma Ligustici Chuanxiong on urinary albumin excretion (UAE) and vascular endothelial dysfunction in type 2 diabetic patients with microalbuminuria. METHODS: Twenty-one type 2 diabetic patients with microalbuminuria were involved in this before-after study by individual informed consent. Each of the eligible subjects was given the decoction of Radix Astragali and Rhizoma Ligustici Chuanxiong per os 150 ml q.d. for six months. The following examinations were performed at baseline and after treatment: (1) high-resolution ultrasonography to measure the diameter changes of brachial artery in response to reactive hyperemia (endothelium-dependent) and on administration of glyceryl trinitrate (endothelium-independent); (2) high resolution ultrasonography to measure combined intima-media thickness (IMT) of common carotid arteries (CCA); (3) fasting plasma plasminogen activator inhibitor type 1 (PAI-1) activity, C reactive protein (CRP) and malonic aldehyde(MDA) concentration. RESULTS: The patients had impaired endothelial dependent vasodilation (EDV), elevated plasma PAI-1 activity and increased CRP and MDA concentration at baseline. After six months treatment with Radix Astragali and Rhizoma Ligustici Chuanxiong, their urinary albumin-to- creatinine ratio decreased from (86.5 +/- 53.9) microg/mg to (55.05 +/- 51.67) microg/mg (P=0.002). The EDV was improved at the end of the treatment (baseline: 7.49 +/- 2.98%, after treatment: 12.73 +/- 5.36%, P=0.001). Meanwhile, the activity of PAI-1 and the levels of MDA and CRP were significantly decreased CPAI-1: (83.49 +/- 5.11) X 10(-2) AU/ml vs. (79.7 +/- 7.8) x 10(-2) AU/ml, P=0.015; MDA: (3.20 +/- 1.13) nmol/L vs. (2.09 +/- 0.71) nmol/L, P=0.000; CRP: (7.04 +/- 2.64) mg/ L vs. (1.58 +/- 0.69) mg/L, P=0.000]. But no significant changes of the CCA IMT and endothelial independent vasodilation (EIV) were observed. Partial correlated analysis showed that MDA concentration was negatively correlated with EDV (r=-0.3736, P = 0.018). Correlated analysis also showed that CRP was negatively correlated with EDV (r=-0.348, P=0.028). CONCLUSION: Radix Astragali and Rhizoma Ligustici Chuanxiong compound medication may decrease urinary albumin excretion and improve endothelial dysfunction in type 2 diabetic patients with microalbuminuria. The mechanism may relate with the therapeutic effects of Radix Astragali and Rhizoma Ligustici Chuanxiong on anti-inflammation, anti-oxidation and alleviation of the hypo-fibrinolytic/pro-thrombotic state.

Adult↗
PubMed2005

Automatic segmentation of echocardiography based on a morphological reconstruction algorithm.

OBJECTIVE: To improve the precision of the traditional segmentation of echocardiogram, by suppressing the influence from inherent speckle noises in medical ultrasonic images. METHOD: An automatic segmentation method based on reconstructed morphology was proposed in this paper. First, the opening and closing operations by reconstruction were imposed to the ultrasonic image. Second, the top-hat operation was used to extract the bright and/or dark features and to find out the boundaries corresponding to these features, whereby implemented the automatic segmentation. RESULT: The segmented echocardiogram had less artificial boundaries resulted from speckle noise, and could accurately be extracted the artery and ventricle. CONCLUSION: The presented method can detect both dark and bright objects accurately, and the boundary has a fine continuity. In addition, the algorithm is also applicable to the extraction of sole bright/dark features, accordingly to reduce the complexity and time needed and to improve the accuracy.

Algorithms↗
PubMed2005

[Spectral feature-based hyperspectral RS image retrieval].

Oriented to the demands of vast RS information management for RS image retrieval, the applications of spectral features are discussed by taking hyperspectral RS image as an example. It is proposed that spectral features-based retrieval includes two modes: retrieval based on point mask an dpolygon mask. The most key issues in retrieval are spectral features extraction andsimilarity measure. The spectral vector can be used to retrieval directly, and the spectral angle and spectral information divergence (SID) are effective in similarity measure. The local maximum and minimum in reflectance spectral curve, corresponding to reflectance apex and absorption apex, can be used to retrieval also, but effective matching strategy should be adopted. The quantitative indexes for spectral curves such as moment, fractal and entropy are not suitable to retrieval because of poor similarity measure performance.

Algorithms↗
PubMed2005

[The analysis of error sources for SAM and its improvement algorithms].

Based on the analysis of the error sources for spectral anglemapping (SAM), several key elements are pointed out, i.e. the change of wave band location, the change of the attribution ratio, the random change of attribution, and the whole translation of wave band. After the above-mentioned four error sources are analyzed, the authors present several improvement algorithms, viz. calculating the spectral angle with grouping, normalization and intersection. The grouping method can resolve the pseudo-similar problem, because it considers both spectral global features and local features. Calculating spectral angle with normalization restrains those random errors in original data by normalizing the spectral vectors. The intersection method can eliminate the error elicited by the whole wave translation. Therefore, it can be employed to correctly identify spectral class. Experiments show that those improvement algorithms are effective and can be used to process spectral data with errors.

Algorithms↗
PubMed2005

[Differentiation of bone marrow mesenchymal stem cells into hepatocytes in hepatectomized mouse].

CD44+ CD29+ and CD44- CD29+ bone marrow mesenchymal stem cells (BMSCs) were isolated from bone marrow of BALB/C male donor mouse by adherence selecting in DMEM media with low glucose and 20% fetal bovine serum. Then P5 cells were injected into the liver remnants of hepatectomined female mouse. Simultaneous assays were performed on the injected liver lobe and other liver lobe for detecting the Y-chromosome by fluorescence in situ hybridization and for defecting the albumin or cytokeratin 18 (CK18) by fluorescence immunoassays. Both Y chromosome and albumin (or CK18) positive cell could be detected at 5 days and 14 days after transplantation. At 14 days after transplantation, the liver weight in transplanted mouse was higher than that in model mouse. These results suggest that BMSCs could be induced to differentiate into hepatocytes and participate in the regeneration of liver.

Animals↗
PubMed2005

[Recommendations for mitral regurgtitation with Doppler echocardiography].

Mitral regurgitation is one of the most serious heart diseases. With the development of up-to-date medical techniques, the ratio of successful operations in valvular repair and valvular replacement has been largely improved. Examinations before operation become extremely crucial. Accurate method is required in assessing the degree of mitral regurgitation to set down the corresponding treatment method. This paper reviews the evaluation methods of mitral valvular regurgitation provided in these years and presents comments on the application areas as well as the merits and disadvantages of those methods. Finally, the prospect of the method based on three-dimensional Doppler ultrasonographic imaging on mitral regurgitation is discussed.

Echocardiography, Doppler, Color↗
PubMed2004

Proteomic fingerprints for potential application to early diagnosis of severe acute respiratory syndrome.

BACKGROUND: Definitive early-stage diagnosis of severe acute respiratory syndrome (SARS) is important despite the number of laboratory tests that have been developed to complement clinical features and epidemiologic data in case definition. Pathologic changes in response to viral infection might be reflected in proteomic patterns in sera of SARS patients. METHODS: We developed a mass spectrometric decision tree classification algorithm using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry. Serum samples were grouped into acute SARS (n = 74; <7 days after onset of fever) and non-SARS [n = 1067; fever and influenza A (n = 203), pneumonia (n = 176); lung cancer (n = 29); and healthy controls (n = 659)] cohorts. Diluted samples were applied to WCX-2 ProteinChip arrays (Ciphergen), and the bound proteins were assessed on a ProteinChip Reader (Model PBS II). Bioinformatic calculations were performed with Biomarker Wizard software 3.1.1 (Ciphergen). RESULTS: The discriminatory classifier with a panel of four biomarkers determined in the training set could precisely detect 36 of 37 (sensitivity, 97.3%) acute SARS and 987 of 993 (specificity, 99.4%) non-SARS samples. More importantly, this classifier accurately distinguished acute SARS from fever and influenza with 100% specificity (187 of 187). CONCLUSIONS: This method is suitable for preliminary assessment of SARS and could potentially serve as a useful tool for early diagnosis.

Adolescent↗
PubMed2004

Tat-dependent repression of human immunodeficiency virus type 1 long terminal repeat promoter activity by fusion of cellular transcription factors.

Transcription initiation from HIV-1 long terminal repeat (LTR) promoter requires the virally encoded transactivator, Tat, and several cellular co-factors to accomplish the Tat-dependent processive transcription elongation. Individual cellular transcription activators, LBP-1b and Oct-1, on the other hand, have been shown to inhibit LTR promoter activities probably via competitive binding against TFIID to the TATA-box in LTR promoter. To explore the genetic interference strategies against the viral replication, we took advantage of the existence of the bipartite DNA binding domains and the repression domains of LBP-1b and Oct-1 factors to generate a chimeric transcription repressor. Our results indicated that the fusion protein of LBP-1b and Oct-1 exhibited higher DNA binding affinity to the viral promoter than the individual factors, and little interference with the host cell gene expression due to its anticipated rare cognate DNA sites in the host cell genome. Moreover, the chimera exerted increased Tat-dependent repression of transcription initiation at the LTR promoter both in vitro and in vivo compared to LBP-1b, Oct-1 or combination of LBP-1b and Oct-1. These results might provide the lead in generating a therapeutic reagent useful to suppress HIV-1 replication.

DNA-Binding Proteins↗
PubMed2004

Essential role of the voltage-dependent anion channel (VDAC) in mitochondrial permeability transition pore opening and cytochrome c release induced by arsenic trioxide.

The precise molecular mechanism underlying arsenic trioxide (As(2)O(3))-induced apoptosis is a subject of extensive study. Here, we show that clinically relevant doses of As(2)O(3) can induce typical apoptosis in IM-9, a multiple myeloma cell line, in a Bcl-2 inhibitable manner. We confirmed that As(2)O(3) directly induced cytochrome c (cyto c) release from isolated mouse liver mitochondria via the mitochondrial permeability transition pore, and we further identified the voltage-dependent anion channel (VDAC) as a biological target of As(2)O(3) responsible for eliciting cyto c release in apoptosis. First, pretreatment of the isolated mitochondria with an anti-VDAC antibody specifically prevented As(2)O(3)-induced cyto c release. Second, in proteoliposome experiments, VDAC by itself was sufficient to mediate As(2)O(3)-induced cyto c release, which could be specifically inhibited by Bcl-X(L). Third, As(2)O(3) induced mitochondria membrane potential (DeltaPsim) reduction and cyto c release only in the VDAC-expressing, but not in the VDAC-deficient yeast strain. Finally, we found that As(2)O(3) induced the increased expression and homodimerization of VDAC in IM-9 cells, but not in Bcl-2 overexpressing cells, suggesting that VDAC homodimerization could potentially determine its gating capacity to cyto c, and Bcl-2 blockage of VDAC homodimerization represents a novel mechanism for its inhibition of apoptosis.

Animals↗
PubMed2004

Data mining techniques for cancer detection using serum proteomic profiling.

OBJECTIVE: Pathological changes in an organ or tissue may be reflected in proteomic patterns in serum. It is possible that unique serum proteomic patterns could be used to discriminate cancer samples from non-cancer ones. Due to the complexity of proteomic profiling, a higher order analysis such as data mining is needed to uncover the differences in complex proteomic patterns. The objectives of this paper are (1) to briefly review the application of data mining techniques in proteomics for cancer detection/diagnosis; (2) to explore a novel analytic method with different feature selection methods; (3) to compare the results obtained on different datasets and that reported by Petricoin et al. in terms of detection performance and selected proteomic patterns. METHODS AND MATERIAL: Three serum SELDI MS data sets were used in this research to identify serum proteomic patterns that distinguish the serum of ovarian cancer cases from non-cancer controls. A support vector machine-based method is applied in this study, in which statistical testing and genetic algorithm-based methods are used for feature selection respectively. Leave-one-out cross validation with receiver operating characteristic (ROC) curve is used for evaluation and comparison of cancer detection performance. RESULTS AND CONCLUSIONS: The results showed that (1) data mining techniques can be successfully applied to ovarian cancer detection with a reasonably high performance; (2) the classification using features selected by the genetic algorithm consistently outperformed those selected by statistical testing in terms of accuracy and robustness; (3) the discriminatory features (proteomic patterns) can be very different from one selection method to another. In other words, the pattern selection and its classification efficiency are highly classifier dependent. Therefore, when using data mining techniques, the discrimination of cancer from normal does not depend solely upon the identity and origination of cancer-related proteins.

Biomarkers, Tumor↗