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Xiong L.,Qingdao | Xiong L.,Qingdao University | Zhang B.,Qingdao | Shen R.-W.,Qingdao | And 9 more authors.
Chinese Journal of Tissue Engineering Research | Year: 2016

BACKGROUND: The mechanism underlying Wallerian degeneration following peripheral nerve injury is complex. Immune regulation on Wallerian degeneration is beneficial for early repair of perpheral nerve injury. OBJECTIVE: To investigate the effects of Toll-like receptor 4 (TLR4) antagonist on Wallerian degeneration and axonal regeneration after early peripheral nerve injury in rats. METHODS: Fifty male Wistar rats were recruited and randomly divided into treatment group (n=20), model group (n=20) and sham group (n=10). The right sciatic nerves of rats in treatment and model groups were cut and sutured end-to-end, while the sciatic nerves of rats in sham group were only exposed. In the treatment group rats were intravenously injected with 0.15 mg/kg TAK-242 via tail vein 1 hour preoperatively and 7 days postoperatively, and the rats in the other two groups were given intravenous injection of the same volume of normal saline. The sciatic nerves were removed at 24 hours, 3, 4 and 7 days after surgery. RESULTS AND CONCLUSION: Real-time PCR indicated that the mRNA expressions of interleukin-1β and monocyte chemoattractant-1 were significantly increased in the model group compared with the sham group at 24 hours after surgery (both P < 0.001), while the expressions were significantly decreased after TAK-242 injection (both P < 0.001). Immunofluorescence showed that compared with the model group, down-regulated expression of CD68+ and iba1+ cells appeared in the treatment group at 3 days after surgery (P < 0.01, P < 0.05). Luxol fast blue staining revealed that demyelination at the sciatic nerve stump appeared in both model and treatment groups at postoperative 7 days, but myelin debris clearance in the treatment group was significantly reduced compared with the model group (P < 0.05). Hematoxylin-eosin staining showed that a lot of inflammatory cells, Schwann cells and regenerated nerve fibers at the sciatic nerve stump were found in the model group, while there were few inflammatory cells, Schwann cells and regenerated nerve fibers in the treatment group at 7 days after surgery. Immunohistochemistry found that the expression of growth-associated protein-43 in the treatment group was significantly lower than that in the model group at 4 days postoperatively (P < 0.05). Besides, compared with the model group, a significantly decreased sciatic functional index was found in the treatment group at 20, 30 and 40 days after surgery (P < 0.05). These results show that TLR4 antagonists delay early nerve regeneration in rats after sciatic nerve injury probably by inhibiting the TLR4 signaling pathway. © 2016, Journal of Clinical Rehabilitative Tissue Engineering Research. All rights reserved.

Hao G.,Chinese Academy of Sciences | Li W.,Chinese Academy of Sciences | Teo K.,McMaster University | Wang X.,Beijing Hypertension League Institute | And 30 more authors.
Angiology | Year: 2014

Weassessed the association between tea consumption and acute myocardial infarction (AMI) using INTERHEART China data. Cases (n = 2909) and controls (n = 2947) were randomly selected and frequency matched by age and sex. Participants who drank tea ≥4 cups/d had a significantly higher risk of AMI than tea nondrinkers; odds ratio (OR) was 1.29 (95% confidence interval [CI]: 1.03-1.61) compared with tea nondrinkers. A similar trend was found in green tea drinkers; OR was 1.52 (95% CI: 1.13-2.05) in the participants who drank 3 cups/d and 1.73 (95% CI: 1.35-2.22) in the participants who drank >4 cups/d compared with tea nondrinkers. We also found that green tea consumption had a greater effect on females; OR was 2.80 (95% CI: 1.43-5.50) in females. In conclusion, we found that the risk of AMI increases as tea consumption increases. Further studies are needed to confirm this association. © The Author(s) 2014.

Fan X.M.,Wuhan Naval University of Engineering | Wang Y.J.,Wuhan Naval University of Engineering | Wang G.L.,Qingdao | Shu C.,Wuhan Naval University of Engineering | Li C.G.,Wuhan Naval University of Engineering
Applied Mechanics and Materials | Year: 2013

In this paper, the main factors influencing the reliability of submarine optical fiber cables (SOFC) are analyzed, and the significance of the research on real-time monitoring technology of SOFC is illuminated. Also, the principle of distributed double Mach-Zehnder (M-Z) interference vibration sensing system is discussed. Then, the feasibility of the system applied in pre-warning and fault location of SOFC is verified. In view of the main problems of the optical fiber vibration sensing system, two optimization schemes are presented in this paper to improve the performance of the system. © (2013) Trans Tech Publications, Switzerland.

Jiang Y.-J.,Taian Central Hospital | Mao C.-G.,Qingdao | Ning X.-F.,Qingdao | Li R.,Qingdao University | Li Z.-P.,Qingdao
Chinese Journal of Tissue Engineering Research | Year: 2015

BACKGROUND: Studies have shown that intramuscular transplantation of xenogeneic umbilical cord mesenchymal stem cells in a certain dose range is safe and reliable, and it also confirm that this approach is equally safe and effective for heart failure in rats with dilated cardiomyopathy. OBJECTIVE: To explore the effect of human umbilical cord mesenchymal stem cells through intramuscular injection on the cytokine expression in adriamycin-induced dilated cardiomyopathy (DCM) rats. METHODS: Totally 160 rats were randomly divided into control group (n=20) and DCM group (n=140). Rats in the DCM group were administered adriamycin intraperitoneally to establish DCM model. The DCM rats were randomly subdivided into model control group (served as model group), cell supernatant group, the low-dose mesenchymal stem cell group (served as low-dose group), the middle-dose mesenchymal stem cell group (served as middle-dose group), and the high-dose mesenchymal stem cells group (served as high-dose group). Secondary injection was performed at 4 weeks after first injection. RESULTS AND CONCLUSION: The ELISA test showed that the serum levels of vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), leukemia inhibitor factor (LIF) and granulocyte macrophage colony stimulating factor (GM-CSF) were higher in the model group than the control group before and after intramuscular injection (P < 0.05). After intramuscular injection, the levels of HGF, LIF, GM-CSF and VEGF in the low-dose group were increased significantly (P < 0.05), which were significantly higher than those in the model group (P < 0.05). The level of LIF in the middle-dose group was significantly elevated after injection (P < 0.05), while there were no significant differences in HGF, VEGF and GM-CSF levels in the high-dose group before and after intramuscular injection (P > 0.05). Both the immunohistochemical and RT-PCR results showed that the expressions of insulin-like growth factor-1, VEGF and HGF were increased in all the DCM rats as compared with the control group, which were increased most in the middle-dose group. These findings indicate that low-dose and middle-dose human umbilical cord mesenchymal stem cells intramuscular injection can increase the serum levels of HGF, LIF, GM-CSF, VEGF and the expressions of IGF-1, HGF and VEGF in the myocardium of DCM rats. © 2015, Journal of Clinical Rehabilitative Tissue Engineering Research. All rights reserved.

Zhang Y.,Qingdao | Jiang C.-Q.,Qingdao | Yu X.-J.,Qingdao Municipal Hospital
Chinese Journal of Tissue Engineering Research | Year: 2015

BACKGROUND: Previous studies have found that cyclic tensile stress can induce the proliferation of human periodontal ligament fibroblasts in a certain time. OBJECTIVE: To observe the effect of cyclic tensile stress on the expression of connective tissue growth factor in human periodontal ligament fibroblasts, and to clarify the role of JNK, p38MAPK, PI3K pathway in the cyclic tensile stress-induced expression of connective tissue growth factor in human periodontal ligament fibroblasts. METHODS: Human periodontal ligament fibroblasts cultured in vitro were given stimulation of cyclic tensile stress in vitro for 1, 6, 12, 24 hours using multi-channel cell stretch stress loading system (experimental group). Control group was set up and not given any stimulation at the same time. The cells under stress application for 12 hours were given specific inhibitors of JNK, p38MAPK, PI3K respectively at the beginning, and were compared with those with no inhibitors. The concentrations of connective tissue growth factor in the culture supernatant were measured by ELISA. The mRNA expression of connective tissue growth factor in human periodontal ligament fibroblasts was detected by real-time RT-PCR. RESULTS AND CONCLUSION: Compared with the control group, the expression of connective tissue growthfactor in human periodontal ligament fibroblasts under cyclic tensile stress began to increase at 1 hour, increased manifestly at 6 hours, reached the peak at 12 hours, and then decreased at 24 hours. The expression of connective tissue growth factor was reduced by the specific inhibitors of JNK, while the specific inhibitors of p38 MAPK, PI3K had not the same effect. In a certain time, the cyclic tensile stress can induce a time-dependent increase in mRNA and protein levels of connective tissue growth factor. Along with the extending of time, the expression of connective tissue growth factor begins to decrease. Cyclic tensile stress can regulate expression of connective tissue growth factor in human periodontal ligament fibroblasts via the JNK pathway. © 2015, Journal of Clinical Rehabilitative Tissue Engineering Research. All rights reserved.

Li D.,Qingdao | Li D.,Ocean University of China | Shi B.,Ocean University of China | Wu G.,Ocean University of China | Liang B.,Ocean University of China
Proceedings of the International Offshore and Polar Engineering Conference | Year: 2016

Submarine pipelines are widely used to deliver oil and gas in offshore petroleum engineering. Local scour can leads to the suspension of pipelines, which can finally results in the pipeline vibration and damage, even oil leaking and marine pollution. Previous research mainly focus on the scour under constant sea conditions, while under variable sea conditions such as storm surges are less studied. Typhoon storm features fast-moving, short duration and intensive wave actions, which can lead to violent seabed sediment movements usually. Based on the characteristics of waves during typhoon storms passing South China Sea, the idealized and simplified cases were generalized with typical wave parameters, including wave height, wave period, and their changeable rules during storm surge passage. A Navier-Stokes solver FLOW-3D was used to establish 2-D numerical simulations under wave conditions mentioned above, following a procedure of wave height increasing, staying stable, and getting lower gradually, following the rules of a typhoon passage. This paper aims to analyze the submarine pipeline scour rules under extreme sea conditions aforementioned, and provide scientific guidance for submarine pipeline design and protection in the near shore area. © Copyright 2016 by the International Society of Offshore and Polar Engineers (ISOPE).

PubMed | Nanyang Technological University and Qingdao
Type: | Journal: Tissue engineering. Part B, Reviews | Year: 2017

Hydrogels have been promising candidate scaffolds for cell delivery and tissue engineering due to their tissue-like physical properties and capability for homogeneous cell loading. However, the encapsulated cells are generally entrapped and constrained in the submicron- or nano-sized gel networks, seriously limiting cell growth and tissue formation. Meanwhile, the spatially-confined settlement inhibits attachment and spreading of anchorage dependent cells, leading to their apoptosis. In recent years, macro-porous hydrogels have attracted increasing attention in use as cell delivery vehicles and tissue engineering scaffolds. The introduction of macro-pores within gel scaffolds not only improves their permeability for better nutrients transport, but also creates spaces/interface for cell adhesion, proliferation and extracellular matrix deposition. Herein, we will first review the development of macro-porous gel scaffolds and outline the impact of macro-pores on cell activities and neo-tissue formation. In the first part, the advantages and challenges of hydrogels as 3-D cell culture scaffolds will be described. In the second part, the fabrication of various macro-porous hydroges will be presented. Thirdly, the enhancement of cell activities and neo-tissue formation within macro-porous gel scaffolds will be discussed. Finally, several crucial factors that are envisaged to propel the improvement of macro-porous gel scaffolds are proposed for 3-D cell culture and tissue engineering.

Meng X.,Qingdao | Qu H.,Qingdao | Zhou C.,Qingdao Municipal Hospital East
Chinese Journal of Gastroenterology | Year: 2012

Diminutive polyp (DP, ≤5 mm in diameter) is the most common type of colorectal polyps detected by colonoscopy, however, studies focusing on endoscopic management of DP are relatively rare. Aims: To analyze the endoscopic and pathological characteristics and management of colorectal DP, thus to provide a reference for its diagnosis and treatment. Methods: Clinical data of patients referred for colonoscopy and diagnosed as having colorectal DP between Jan. 2010 and Apr. 2011 at Qingdao Municipal Hospital were collected. Those with synchronous polyps ≥6 mm in diameter were excluded. Endoscopic and pathological characteristics and management of DP were analyzed retrospectively. Results: A total of 269 patients with 402 colorectal DPs were enrolled, which accounted for 21.8% of the polyps cases. Of the 269 patients, 180 (66.9%) had only a single DP. 43.3% of the DPs were located in the rectum and sigmoid colon, and 60.0% of the DPs were ≥3 mm in diameter. Most DPs appeared as Yamada type I (53.5%) or Yamata type I (42.0%). Of the 305 DPs received pathological evaluation, most were adenomatous polyps (50.2%) or inflammatory polyps (47.5%). DPs>3 mm were more likely to be neoplastic, while those ≤3 mm were more likely to be nonneoplastic (P<0.05). 66.9% of the DPs were removed by cold biopsy. As compared with DPs ≤3 mm, Yamata type I DPs and solitary DP, it was more likely that DPs >3 mm, Yamada type II + III DPs and multiple DPs were removed by hot biopsy or high frequency electrotomy (P<0.05). Conclusions: Endoscopic high frequency electrotomy may be more effective for colorectal DP >3 mm in diameter, and pathological evaluation is necessary for avoiding the missing diagnosis of advanced adenoma.

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