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Articles by W Sun
Total Records ( 7 ) for W Sun
  W Sun , X Gao , X Zhao , D Cui and Q. Xia

The study was undertaken to examine the effects of C-peptide on glomerular volume (VGLOM), mesangial matrix synthesis, and degradation in streptozotocin (STZ)-diabetic rats with poor or moderate glycemic control. Series 1 (poor glycemic control) included groups of healthy rats, hyperglycemic rats, diabetic insulin-treated rats and diabetic C-peptide-treated rats. Series 2 (moderate glycemic control) included groups of healthy rats, diabetic insulin-treated rats, diabetic insulin- and C-peptide-treated rats. After 8 weeks, the left kidney was excised for evaluation of VGLOM and mesangial matrix area via light microscopy. Mesangial cells were cultured for 48 h and type IV collagen expression and matrix metalloproteinase (MMP)-2 expression were measured by ELISA and RT–PCR. The results indicated that in Series 1, C-peptide administration suppressed the diabetes-induced increase in the VGLOM and the mesangial matrix area. In Series 2, C-peptide administration resulted in a similar decrease in the VGLOM and a greater decrease in the mesangial matrix area when compared with insulin therapy alone. Moreover, C-peptide (300 nM) completely inhibited the glucose-induced increase of the collagen IV mRNA expression and protein concentration in mesangial cells cultured in 30 mM glucose medium. MMP-2 mRNA expression was not influenced by C-peptide. In conclusion, C-peptide administration to STZ-diabetic rats for 8 weeks results in the inhibition of diabetes-induced expansion of the mesangial matrix. This effect is independent of the level of glycemic control and results from the inhibition of diabetes-induced excessive formation of mesangial type IV collagen.

  X Wu , W Zhang , X Shi , P An , W Sun and Z. Wang

In this study, we investigated the therapeutic effect of artemisinin (Art) on lupus nephritis mice and its mechanisms by comparing the differences between lupus nephritis (LN) mice given Art and control mice in molecular biology, immunohistochemistry, and histopathology. The results showed that Art could remarkably relieve the symptoms, decrease the level of urine protein/24 h, and alleviate pathological renal lesions. The differences among the four groups in the expression of the NF-Bp65 protein, nuclear factor-B (NF-B) activity, and the expression of transforming growth factor-β1 (TGF-β1) mRNA in renal tissue suggested that Art can lower the serum levels of tumor necrosis factor- (TNF-) and interleukin-6 (IL-6) and inhibit the expression of the NF-Bp65 protein and NF-B and TGF-β1 mRNA in the renal tissues of LN mice. These results proved that it is reliable and effective to use Art to treat LN mice, and its therapeutic mechanisms should closely be related to the fact that Art can obviously decrease the serum levels of TNF- and IL-6 and down-regulate the expression of the NF-Bp65 protein and NF-B and TGF-β1 mRNA in renal tissues.

  W Sun , H Xie , J Ji , X Zhou , D Goltzman and D. Miao

We used mice with targeted deletion of 25-hydroxyvitamin D 1-hydroxylase [1(OH)ase–/–] to investigate the effects of calcium and phosphorus on defects in the reproductive system of 1,25-dihydroxyvitamin D [1,25(OH)2D]-deficient female mice. The 1(OH)ase–/– mice and their wild-type littermates were fed either a normal diet or a rescue diet (high calcium, phosphate, and lactose) starting from weaning until 3 mo of age. We then determined serum calcium and phosphorus levels, assessed gonadotropin and gonadal hormone production, and evaluated folliculogenesis, corpus luteum formation, ovarian angiogenesis, uterus development, and fertility. Results showed that hypocalcemic and hypophosphatemic female 1(OH)ase–/– mice developed infertility accompanied by decreased estrogen and progestogen levels, elevated follicle-stimulating hormone and luteinizing hormone levels, defects in follicular development and corpus luteum formation, uterine hypoplasia, and decreased ovarian expression of angiogenic factors including vascular endothelial growth factor (VEGF), angiopoietin-1 and -2, and Tie-2. When serum calcium and phosphorus were normalized by the rescue diet, the defective reproductive phenotype in the female 1(OH)ase–/– mice, including the dysfunction in the hypothalamic-pituitary-ovarian axis, and ovarian angiogenesis were reversed. These results indicate that the infertility seen in 1,25(OH)2D-deficient mice is not a direct effect of active vitamin D deficiency on the reproductive system but is an indirect effect mediated by extracellular calcium and phosphorus.

  J Kong , X Li , Y Wang , W Sun and J. Zhang

Objective  To assess the impact of digital problem-based learning (PBL) cases on student learning in ophthalmology courses.

Methods  Ninety students were randomly divided into 3 classes (30 students per class). The first class studied under a didactic model. The other 2 classes were divided into 6 groups (10 students per group) and received PBL teaching; 3 groups studied via cases presented in digital form and the others studied via paper-form cases. The results of theoretical and case analysis examinations were analyzed using the 2 test. Student performance on the interval practice was analyzed using the Kruskal-Wallis test. Questionnaires were used to evaluate student and facilitator perceptions.

Results  Students in the digital groups exhibited better performance in the practice procedures according to tutorial evaluations compared with the other groups (P < .05). The 2 PBL classes had significantly higher mean results of theoretical and case analysis examinations (P < .001), but there was no significant difference between the 2 PBL classes. Ninety-three percent of students in the digital groups (vs 73% in the paper groups) noted that the cases greatly stimulated their interest.

Conclusions  Introducing PBL into ophthalmology could improve educational quality and effectiveness. Digital PBL cases stimulate interest and motivate students to further improve diagnosis and problem-handling skills.

  J Ding , G He , W Gong , W Wen , W Sun , B Ning , S Huang , K Wu , C Huang , M Wu , W Xie and H. Wang

Frequent exposure to nickel compounds has been considered as one of the potential causes of human lung cancer. However, the molecular mechanism of nickel-induced lung carcinogenesis remains obscure. In the current study, slight S-phase increase, significant G2/M cell cycle arrest, and proliferation blockage were observed in human bronchial epithelial cells (Beas-2B) upon nickel exposure. Moreover, the induction of cyclin D1 and cyclin E by nickel was shown for the first time in human pulmonary cells, which may be involved in nickel-triggered G1/S transition and cell transformation. In addition, we verified that hypoxia-inducible factor-1, an important transcription factor of nickel response, was not required for the cyclin D1 or cyclin E induction. The role of p53 in nickel-induced G2/M arrest was excluded, respecting that its protein level, ser15 phosphorylation, and transcriptional activity were not changed in nickel response. Further study revealed that cyclin A was not activated in nickel response, and cyclin B1, which not only promotes G2/M transition but also prevents M-phase exit of cells if not degraded in time, was up-regulated by nickel through a manner independent of hypoxia-inducible factor. More importantly, our results verified that overexpressed cyclin B1, veiling the effect of cyclin D1 or cyclin E, mediated nickel-caused M-phase blockage and cell growth inhibition, which may render pulmonary cells more sensitive to DNA damage and facilitates cancer initiation. These results will not only deepen our understanding of the molecular mechanism involved in nickel carcinogenecity, but also lead to the further study on chemoprevention of nickel-associated human cancer. (Cancer Epidemiol Biomarkers Prev 2009;18(6):1720–9)

  J Won Lee , W. R Kim , W Sun and M. W. Jung

Humans and animals form internal representations of external space based on their own body movement (dead reckoning) as well as external landmarks. It is poorly understood, however, how different types of information are integrated to form a unified representation of external space. To examine the role of dentate gyrus (DG) in this process, we conducted physiological and behavioral experiments using Bax knockout (Bax-KO) mice in which newly generated granule cells continue to accumulate disrupting neural circuitry specifically in the DG. Unlike in wild-type (WT) littermates, spatial firing of hippocampal neurons was completely dissociated from a distinct visual cue and instead, tended to stay constant relative to the recording room in Bax-KO mice. Behaviorally, whereas spatial learning was intact in conventional spatial reference memory tasks, Bax-KO mice were impaired in finding a target location based on visual landmarks when target locations predicted by dead reckoning and visual landmarks were made incongruent. These results provide converging evidence for the role of DG in binding animal's internal spatial map with the sensory information on external landmarks in building a distinct spatial representation for each environment.

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