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Biomedical subjects

Hongyu Yang

Publications and source records attributed to Hongyu Yang.

10 recordsLinked to original sources

Gender difference in hemodynamic responses of prefrontal area to emotional stress by near-infrared spectroscopy.

Presentation of negative pictures was used as emotional stress to assess gender differences in prefrontal area activation in a functional near-infrared spectroscopy (NIRS) study. Compared with neutral condition, the response of oxy-HB for men yielded no significant difference during stress period, but the response induced by stress pictures for women showed significant enhancement. It was indicated that it is crucial to take gender difference into account when negative stimuli are used in functional brain imaging.

Adult↗

Diffuse dermal angiomatosis of the breast.

BACKGROUND: Diffuse dermal angiomatosis is rare and usually considered a variant of reactive angioendotheliomatosis. It generally involves the extremities of patients with severe vascular disease and other comorbidities. Two patients with breast involvement have been described; however, neither had a relevant medical history or a vaso-occlusive disorder, but both had large pendulous breasts, and 1 was positive for IgM anticardiolipin and antinuclear antibodies. OBSERVATIONS: A 53-year-old woman had a reticulated, erythematous plaque with superficial ulceration and underlying tender nodules on her left breast. She had a history of cardiovascular disease and was a heavy smoker. Biopsy of the lesion showed diffuse proliferation of additional endothelial cells and small bland vessels within the papillary and upper reticular dermis. Angiography showed almost complete occlusion of the subclavian artery proximally. Diffuse dermal angiomatosis was diagnosed. With isotretinoin therapy, the lesions improved. One month later, after percutaneous subclavian arterial revascularization, the lesion resolved completely. A literature review suggested that a history of heavy smoking, in addition to a history of vascular disease, may be important in the pathogenesis of diffuse dermal angiomatosis. CONCLUSIONS: Clinical acumen is crucial to diagnose diffuse angiomatosis of the breast. Appropriate treatment to alleviate hypoxia may improve the patient's condition.

Angiomatosis↗

OxfordGrid: a web interface for pairwise comparative map views.

SUMMARY: OxfordGrid is a web application and database schema for storing and interactively displaying genetic map data in a comparative, dot-plot, fashion. Its display is composed of a matrix of cells, each representing a pairwise comparison of mapped probe data for two linkage groups or chromosomes. These are arranged along the axes with one forming grid columns and the other grid rows with the degree and pattern of synteny/colinearity between the two linkage groups manifested in the cell's dot density and structure. A mouse click over the selected grid cell launches an image map-based display for the selected cell. Both individual and linear groups of mapped probes can be selected and displayed. Also, configurable links can be used to access other web resources for mapped probe information. AVAILABILITY: OxfordGrid is implemented in C#/ASP.NET and the package, including MySQL schema creation scripts, is available at ftp://cggc.agtec.uga.edu/OxfordGrid/.

Algorithms↗

IntegratedMap: a Web interface for integrating genetic map data.

SUMMARY: IntegratedMap is a Web application and database schema for storing and interactively displaying genetic map data. Its Web interface includes a menu for direct chromosome/linkage group selection, a search form for selection based on mapped object location and linkage group displays. An overview display provides convenient access to the full range of mapped and anchored object types with genetic locus details, such as numbers, types and names of mapped/anchored objects displayed in a compact scrollable list box that automatically updates based on selected map location and object type. Also, multilinkage group and localized map views are available along with links that can be configured for integration with other Web resources. AVAILABILITY: IntegratedMap is implemented in C#/ASP.NET and the package, including a MySQL schema creation script, is available from http://cggc.agtec.uga.edu/Data/download.asp

Algorithms↗

The androgen receptor gene is preferentially hypermethylated in follicular non-Hodgkin's lymphomas.

This investigation examined promoter DNA methylation of the androgen receptor (AR) gene in non-Hodgkin's lymphoma (NHL) representing different stages of B-cell differentiation. Steroid hormones are important endocrine messengers with a broad range of physiological functions, including regulation of B-cell lymphopoiesis. Some of these effects are mediated via specific receptors such as AR that can act as a ligand-dependent transcription factor for other genes. DNA was isolated from 76 NHL specimens representing pregerminal center, germinal center, and postgerminal center states of differentiation. Initial methylation data were obtained from oligonucleotide microarrays and was confirmed and extended using methylation-specific PCR. Methylation of the AR gene promoter was present in a nonrandom pattern. Those tumors derived from pregerminal center or postgerminal center stages showed virtually no methylation and expressed AR mRNA. Cases of germinal center origin, mainly follicular lymphomas and some diffuse large B-cell lymphomas, showed hypermethylation. Studies with NHL cell lines revealed that demethylation or reversal of histone deacetylation partially restored AR expression but reversal of both simultaneously provided a synergistic release from suppression. Promoter methylation of AR occurs in a differentiation stage-selective manner; those cases arising in the germinal center are preferentially methylated. Full re-expression of AR requires both demethylation and reacetylation, a finding that may affect treatment decisions.

Cell Line, Tumor↗

Synoviocyte-mediated expansion of inflammatory T cells in rheumatoid synovitis is dependent on CD47-thrombospondin 1 interaction.

Fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis elicit spontaneous proliferation of autologous T cells in an HLA-DR and CD47 costimulation-dependent manner. T cell costimulation through CD47 is attributed to specific interaction with thrombospondin-1 (TSP1), a CD47 ligand displayed on FLS. CD47 binding by FLS has broad biological impact that includes adhesion and the triggering of specific costimulatory signals. TSP1(+) FLS are highly adhesive to T cells and support their aggregation and growth in situ. Long-term cultures of T cells and FLS form heterotypic foci that are amenable to propagation without exogenous growth factors. T cell adhesion and aggregate formation on TSP1(+) FLS substrates are inhibited by CD47-binding peptides. In contrast, FLS from arthroscopy controls lack adhesive or T cell growth-promoting activities. CD47 stimulation transduces a costimulatory signal different from that of CD28, producing a gene expression profile that included induction of ferritin L chain, a component of the inflammatory response. Ferritin L chain augments CD3-induced proliferation of T cells. Collectively, these results demonstrate the active role of FLS in the recruitment, activation, and expansion of T cells in a CD47-dependent manner. Because TSP1 is abundantly expressed in the rheumatoid synovium, CD47-TSP1 interaction is proposed to be a key component of an FLS/T cell regulatory circuit that perpetuates the inflammatory process in the rheumatoid joint.

Adjuvants, Immunologic↗

[The effect of anti-ICAM-1/LAF-1 McAb on the cytotoxicity of tumor infiltrating lymphocytes from oral squamous cell carcinoma].

OBJECTIVE: To investigate the effect of anti-ICAm-1/LAF-1 McAb on the cytotoxicity of tumor infiltrating lymphocytes from oral squamous cell carcinoma. METHODS: TIL were isolated from fresh tumor tissues in 15 patients with oral squamous cell carcinoma and cultured in vitro. The expression of ICAM-1/LAF-1 in fresh and activated TIL was examined by FACS. The cytotoxicity of TIL against auto tumor cells and the level of TNF-alpha produced by TIL were compared before and after interrupted with anti-ICAM-1/LAF-1 McAb. RESULTS: The expression of ICAM-1 and LAF-1 in the activated TIL significantly increased comparing with fresh TIL (P < 0.05). Interrupted by anti-ICAM-1 McAb, the cytotoxicity of TIL against auto tumor cell was not significantly changed. Interrupted by anti-ICAM-1 and anti-LAF-1 McAb, the level of TNF-alpha produced by TIL showed no differences comparing with the control (P < 0.05), but the cytotoxicity of TIL against auto tumor cells significantly decreased (P < 0.05). CONCLUSION: The effect of anti-LAF-1 McAb may result from steric interference of antigen-nonspecific adhesion process.

Antibodies, Monoclonal↗

Transformation of peanut using a modified bacterial mercuric ion reductase gene driven by an actin promoter from Arabidopsis thaliana.

In order to test an alternative selectable marker system for the production of transgenic peanut plants (Arachis hypogaea), the bacterial mercuric ion reductase gene, merA, was introduced into embryogenic cultures via microprojectile bombardment. MerA reduces toxic Hg(II) to the volatile and less toxic metallic mercury molecule, Hg(0), and renders its source Gram-negative bacterium mercury resistant. A codon-modified version of the merA gene, MerApe9, was cloned into a plant expression cassette containing the ACT2 promoter from Arabidopsis thaliana and the NOS terminator. The expression cassette also was inserted into a second vector containing the hygromycin resistance gene driven by the UBI3 promoter from potato. Stable transgenic plants were recovered through hygromycin-based selection from somatic embryo tissues bombarded with the plasmid containing both genes. However, no transgenic somatic embryos were recovered from selection on 50-100 micromol/L HgCl2. Expression of merA as mRNA was detected by Northern blot analysis in leaf tissues of transgenic peanut, but not in somatic embryos. Western blot analysis showed the production of the mercuric ion reductase protein in leaf tissues. Differential responses to HgCl2 of embryo-derived explants from segregating R1 seeds of one transgenic line also were observed.

Actins↗

CD8 T cells are required for the formation of ectopic germinal centers in rheumatoid synovitis.

The assembly of inflammatory lesions in rheumatoid arthritis is highly regulated and typically leads to the formation of lymphoid follicles with germinal center (GC) reactions. We used microdissection of such extranodal follicles to analyze the colonizing T cells. Although the repertoire of follicular T cells was diverse, a subset of T cell receptor (TCR) sequences was detected in multiple independent follicles and not in interfollicular zones, suggesting recognition of a common antigen. Unexpectedly, the majority of shared TCR sequences were from CD8 T cells that were highly enriched in the synovium and present in low numbers in the periphery. To examine their role in extranodal GC reactions, CD8 T cells were depleted in human synovium-SCID mouse chimeras. Depletion of synovial CD8 T cells caused disintegration of the GC-containing follicles. In the absence of CD8 T cells, follicular dendritic cells disappeared, production of lymphotoxin-alpha1beta2 markedly decreased, and immunoglobulin (Ig) secretion ceased. Immunohistochemical studies demonstrated that these CD8 T cells accumulated at the edge of the mantle zone. Besides their unique localization, they were characterized by the production of interferon (IFN)-gamma, lack of the pore-forming enzyme perforin, and expression of CD40 ligand. Perifollicular IFN-gamma+ CD8 T cells were rare in secondary lymphoid tissues but accounted for the majority of IFN-gamma+ cells in synovial infiltrates. We propose that CD8+ T cells regulate the structural integrity and functional activity of GCs in ectopic lymphoid follicles.

Adolescent↗

Therapeutic effects of acetylsalicylic acid in giant cell arteritis.

OBJECTIVE: In giant cell arteritis (GCA), inflammatory lesions typically produce interferon-gamma(IFNgamma)-- and nuclear factor kappaB (NF-kappaB)-dependent monokines. Corticosteroids influence disease activity by repressing NF-kappaB-dependent genes but have only marginal effects on IFNgamma. The current study explored whether acetylsalicylic acid (ASA) had cytokine-repressing activity in GCA and could function as a steroid-sparing agent. METHODS: Temporal artery-severe combined immunodeficiency (SCID) mouse chimeras were created by engrafting inflamed temporal arteries into SCID mice. Chimeras were treated with ASA, indomethacin, or dexamethasone for 3 weeks. Temporal artery grafts were harvested and cytokine message was semiquantified by polymerase chain reaction-enzyme-linked immunosorbent assay. The ability of dexamethasone and ASA to suppress IFNgamma and interleukin-1beta (IL-1beta) messenger RNA and protein production was also tested in vitro using T cell clones and monocytes derived from patients with GCA. Drug-induced effects on the transcription factors NF-kappaB and activator protein 1 (AP-1) were assessed by electrophoretic mobility shift assays (EMSAs). RESULTS: At clinically relevant doses, 20-100 mg/kg, ASA was a highly effective inhibitor of cytokine transcription in temporal arteries. While dexamethasone preferentially targeted NF-kappaB-regulated monokines, ASA acted predominantly by suppressing IFNgamma. Indomethacin failed to reduce tissue IFNgamma transcription, which therefore excluded the inhibition of cyclooxygenases as a critical mechanism. IFNgamma production by T cell clones was highly sensitive to ASA-mediated suppression, whereas IL-1beta production by lipopolysaccharide-stimulated monocytes responded primarily to dexamethasone. The combination of ASA and dexamethasone had synergistic effects. EMSAs demonstrated that ASA interfered with the formation of AP-1, whereas dexamethasone suppressed the nuclear translocation of NF-kappaB. CONCLUSION: The results of this study provide evidence of the complementary action of ASA and corticosteroids in suppressing proinflammatory cytokines in the vascular lesions of GCA.

Animals↗