Biomedical subjects

Yan Wu

Publications and source records attributed to Yan Wu.

149 records · Page 9Linked to original sources

PubMed2002

Cx40 and Cx43 expression ratio influences heteromeric/ heterotypic gap junction channel properties.

In cells that coexpress connexin (Cx)40 and Cx43, the ratio of expression can vary depending on the cellular environment. We examined the effect of changing Cx40:Cx43 expression ratio on functional gap junction properties. Rin cells transfected with Cx40 or Cx43 (Rin40, Rin43) were cocultured with 6B5n, A7r5, A7r540C1, or A7r540C3 cells for electrophysiological and dye coupling analysis. Cx40:Cx43 expression ratio in 6B5n, A7r5, A7r540C1, and A7r540C3 cells was ~1:1, 3:1, 5:1, and 10:1, respectively. When Rin43 cells were paired with coexpressing cells, there was an increasing asymmetry of voltage-dependent gating and a shift toward smaller conductance events as Cx40:Cx43 ratio increased in the coexpressing cell. These observations could not be predicted by linear combinations of Cx40 and Cx43 properties in proportion to the expressed ratios of the two Cxs. When Rin40 cells were paired with coexpressing cells, the net voltage gating and single-channel conductance behavior were similar to those of Rin40/Rin40 cell pairs. Dye permeability properties of cell monolayers demonstrated that as Cx40:Cx43 expression ratio increased in coexpressing cells the charge and size selectivity of dye transfer reflected that of Rin40 cells, as would be predicted. These data indicate that the electrophysiological properties of heteromeric/heterotypic channels are not directly related to the proportions of Cx constituents expressed in the cell; however, the dye permeability of these same channels can be predicted by the relative Cx contributions.

Animals↗

PubMed2002

A comparison of coping factors in Western and non-Western cultures.

This study presents convergent support for the use of three empirically constructed factors, across four samples, from the Ways of Coping Questionnaire. Planning, Positive Reappraisal, and Distancing factors were congruent for comparisons made between U.S. healthcare workers, Chinese healthcare workers, Chinese teachers, and Taiwanese teachers. Additional evidence of congruency was provided on specific factors between specific pairs of groups. The results support the usage of common factors across languages, cultures, and occupational groups but also highlight the importance of not administering a test in a different cultural setting without assessing its dimensionality.

Adaptation, Psychological↗

PubMed2000

Construction and Characterization of Recombinant Adenoviruses Expressing Biologically Active Human Brain-derived Neurotrophic Factor and Neurotrophin-3.

In order to deliver brain-derived neurotrophic factor(BDNF) and neurotrophin-3(NT3) into CNS to prevent or reduce degeneration of CNS neurons in human neurodegenerative diseases and neuron injuries, recombinant adenoviruses Ad-BDNF and Ad-NT3 were constructed. BDNF and NT3 genes were inserted into an E1-substituted adenovirus shuttle plasmid, respectively, and were driven by the human cytomegalovirus immediate-early gene promoter/enhancer. After cotransfection into 293 cells with the adenovirus plasmid pJM17, the recombinant adenovirus Ad-BDNF and Ad-NT3 were propagated in 293 cells via homologous recombination. After two rounds of CsCl centrifugation, the human recombinant adenovirus Ad-BDNF and Ad-NT3 were obtained with titer of 1x10(12) and 8x10(11) pfu/ml, respectively. To examine the expression of BDNF and NT3, HeLa cells were infected with Ad-BDNF and Ad-NT3, respectively. RT-PCR, Western blot and ELISA analysis results showed that BDNF and NT3 genes could be transcribed and translated in Ad-BDNF and Ad-NT3 infected HeLa cells. And the culture media containing 10% conditioned medium of Ad-BDNF and Ad-NT3 infected Hela cells could induce the neurite outgrowth from E8 dorsal root ganglion neurons.

Journal Article↗

PubMedDate not supplied

Idiopathic IgA nephropathy with diffuse crescent formation.

OBJECTIVE: To investigate the clinicopathological features and outcome of idiopathic IgA nephropathy with diffuse crescent formation in Chinese patients. METHODS: Twenty-five patients with diffuse crescentic IgA nephropathy (DCIgAN), 15 males and 10 females with median age of 28.5, and median disease duration of 5.1 months, were studied. Their clinical, laboratory and pathological features and outcome were investigated. Twenty-one were administered pulse immunosuppressive therapy, and 15 were followed up for more than 6 months. RESULTS: 1.14% had total IgA nephropathy, and 16.4% total diffuse crescentic glomerulonephritis. Clinically, most of patients (88%) showed rapidly progressive glomerulonephritis associated with a high level of serum creatinine (418 +/- 264 micromol/l). Gross hematuria was noted in 72%, hypertension in 64%, and nephrotic syndrome in 48%. Pathologically, except for diffuse crescent formation (a median 65% and range 50-95%), we observed segmental necrosis of glomerular capillaries in 60%, glomerular infiltrating cells in 48%, endothelial cells proliferation in 32%, and rupture of Bowmans' capsule in 24%. Severe tubular interstitial damage was also found, tubular atrophy in 64%, interstitial fibrosis in 60%, diffuse interstitial infiltrating cells in 74%, and interstitial vasculitis in 40%. Immunopathologically, four phenotypes were observed; however, IgA associated with IgM deposition was higher than that in patients with general IgA nephropathy (IgAN). In addition, the infiltrating CD4+, CD8+, CD68+ and PCNA+ cells in renal tissue were significantly high compared with that in controls. In a follow-up study, 66.7% of patients had life-sustaining renal function, 4 of them had normal range of serum creatinine (<124 micromol/l), and only 5 were dialysis-dependent. CONCLUSIONS: The patients with crescentic IgA nephropathy mostly show rapidly progressive nephritis associated with more severe pathological changes including glomerular, tubular interstitial and vascular lesions than in patients with general IgAN. The infiltrates in glomeruli may contribute to the crescentic formation, and the intensive immune suppressing treatment is useful to improve renal damage in patients with DCIgAN.

Adult↗

PubMedDate not supplied

Differential reactions of microglia to brain metastasis of lung cancer.

The brain is a common metastatic site for various types of cancers, especially lung cancer. Patients with brain metastases have a poor prognosis in spite of radiotherapy and/or chemotherapy. It is postulated that immune cells in the brain may play a major role in cancer metastasis, dormancy, and relapse. Although microglia may serve as a major component in the brain immune system, the interaction between metastatic cancer cells and microglia is still largely unknown and remains to be elucidated. In this study, we have investigated microglial reactions in brain tissues with metastatic lung cancer cells and evaluated the cytotoxic effects of lipopolysaccharide (LPS)-activated microglia on metastatic lung cancer cells in vitro. In the vicinity of metastatic lung cancer mass in the brain, microglia showed signs of significant activation. There was an obvious increase in the number of microglia labeled with ionized calcium binding adaptor molecule 1 (Iba-1) antibody, a specific marker of microglia. The microglia were observed to form a clear boundary between the tumor mass and normal brain tissue. In the region where the tumor mass was situated, only a few microglia expressed inducible nitric oxide synthase (iNOS) and tumor necrosis factor-alpha (TNF-alpha), indicating differential activation in those microglia. The supernatant from LPS-activated microglia induced apoptosis of metastatic lung cancer cells in vitro in a dose- and time-dependent manner. However, at lower concentrations of activated microglial supernatant, trophic effects on cancer cells were observed, some lung cancer cells being insensitive to microglial cytotoxicity. Together with the observation that TNF-alpha alone induced proliferation of the tumor cells, the findings provide possible clues to the mechanism involved in metastasis of lung cancer cells to the brain.

Animals↗