4,051 research outputs found
Macrophage polarization plays a role in intermittent hypoxia (IH)-impaired subcutaneous adipogensis in an IH-exposed mouse model
No full textINTRODUCTION: Obesity is associated with majority of obstructive sleep apnoea (OSA)–related morbidities including cardiovascular and metabolic disorders. Impairment of adipogenic capacity in pre-adipocytes may promote adipocyte hypertrophy and increase the risks of insulin resistance and type 2 diabetes. Recent research findings have suggested an inhibitory role of macrophage polarisation in adipogenesis. However, the impact of intermittent hypoxia (IH), as a characteristic pathophysiologic feature in OSA, on adipogenesis is unknown. This study investigated the impact of IH on adipogenesis and further explored the role of macrophage polarisation in IH-regulated adipogenic process. METHOD: C57BL/6N male mice were exposed to either IH or room air (RA) for 6 weeks. The profile of IH was cycles of approximately 240 seconds of 10% O2 and 120 seconds of 21% O2, ie 10 cycles/hour. Epididymal adipose tissue (AT) and abdominal AT were isolated to represent visceral (VIS) and subcutaneous (SUB) AT, respectively. Stromal vascular fraction (SVF) from depot-specific AT was isolated, cultured, and underwent two differentiation cycles in vitro. Macrophage-conditioned media from cultured RAW264.7 cell line were also incubated with SUB SVF and VIS SVF during adipogenic differentiation. Oil Red O staining was carried out for identification of oily droplets. Assessments of differentiation-associated markers, adipogenic transcriptional factors, and macrophage markers were achieved by real-time polymerase chain reaction. Morphological change and M1 macrophage infiltration were detected by H&E and immunofluorescence staining on formalin-fixed and paraffin-embedded AT sections (10 μm), respectively. RESULT: After adipogenic differentiation in vitro, oily droplets of SUB SVF from IH-exposed mice were significantly down-regulated in comparison with that derived from RA mice, whilst the inhibitory effect of IH on oily droplets was not observed in VIS SVF. In agreement with the production of oily droplets, differentiation associated markers and adipogenic transcriptional factors were also suppressed in SUB SVF from IH-exposed mice. IH exposure caused hypertrophic adipocytes in SUB AT but not in VIS AT. Furthermore, IH exposure increased infiltration of preferentially M1 macrophages in SUB AT, in line with the reduction of M2 phenotype and increment of M1 phenotype markers in SUB SVF. In support, conditioned-medium from RAW264.7 (M1 macrophage dominant) significantly inhibited the adipogenesis of SUB SVF, suggesting the involvement of macrophage polarisation in IH-inhibited adipogenesis. CONCLUSION: Macrophage polarisation may be a potential mechanism responsible for IH-impaired subcutaneous adipogenesis
Configuration of a source array for rendering a planar propagating wave field in an interior space
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Cellular mechanisms involved in intermittent hypoxia-induced heart damage in rat
Full text linkBACKGROUND: Obstructive sleep apnoea (OSA), characterised by intermittent hypoxia (IH) during sleep, is increasingly recognised as an independent risk factor of cardiovascular diseases (CVD). OSA has been reported to be associated with changes in the levels of circulating oxidative stress and inflammatory markers as well as dyslipidemia, supporting their mediating roles in cardiovascular pathogenesis. This study aimed to investigate the ...published_or_final_versionThe 17th Medical Research Conference, Department of Medicine, The University of Hong Kong, Hong Kong, 14 January 2012. In Hong Kong Medical Journal, 2012, v. 18 n. 1, suppl. 1, p. 23, abstract no. 2
Marine fish fauna in Hong Kong waters
No full textMarine fish fauna in Hong Kong Waters. Zoological Studies 38(2). 130-152. Rapid industrialization and large-scale infrastructural projects in Hong Kong and the Pearl River Delta in recent years have placed an extraordinarily heavy burden on coastal environments. The magnitude of the problem will increase as sewage discharge, ocean dredging/disposal, and land reclamation continue to expand in the next few years. Fundamentals of marine environmental impact assessment are based upon a good understanding of biodiversity that allow us to monitor environmental changes. However, there is no baseline data on marine fauna that allow evaluation of the damage from various large-scale infrastructural projects to aquatic environments. A comprehensive database on local fish fauna is, therefore, urgently necessary for the planning and implementation of conservation strategies in Hong Kong. This paper is the ist systematic report on marine fish fauna in Hong Kong waters. From years of opportunistic fishing surveys and a thorough literature review, a total of 25 orders, 124 families, 390 genera, and 834 fish species in Hong Kong waters were identified. There are 97 fish species listed herein as new records to the area
Disposition of information entities and adequate level of information presentation in an in-car augmented reality navigation system
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Evaluation of System Configuration to Check the Suitability for the Sound Field Rendering Using the Inverse Approach
No full textYuehan Hengli Niuman de zi you jing shen yu fan zi you lun shu
No full textMong, Ih-ren Ambrose.Thesis (M.Phil.)--Chinese University of Hong Kong, 2010.Includes bibliographical references (leaves 139-144).Abstracts in English and Chinese.Introduction --- p.1Chapter 1. --- "What, then, does Dr. Newman mean by Liberalism?" --- p.7Chapter 2 --- Biographical Sketch --- p.22Chapter 3 --- A Critic of Liberalism --- p.46Chapter 4 --- The Liberalism of Newman --- p.80Chapter 5 --- Newman's Liberalism in the Context of Contemporary Pluralism --- p.103Conclusion --- p.131Bibliography --- p.13
Cardiac and Pulmonary Inflammatory Responses by Intermittent Hypoxia in C57BL/6N and C57BL/6J Mouse Strains
No full textIntroduction: Mouse inbred lines C57BL/6N (6N) and C57BL/6J (6J) are both widely used as animal models of obstructive sleep apnea (OSA), which is characterized by intermittent hypoxia (IH). In the current study, we investigated the degree of susceptibility to IH on cardiac and pulmonary inflammation between the two sub-strains. Methods: Equal numbers of 13-week old male mice of 6N (n = 8; Strain code: 027; Charles River, NCI Research Models and Services, Frederick, Maryland, USA) and 6J (n=8; Stock #000664; Jackson Laboratories, Bar Harbor, Maine, USA) sub-strains were randomly subjected to intermittent normoxia (IN) or IH (IH30; thirty hypoxic events per hour; BioSpherix, USA) for one week. Between different groups, the pro-inflammatory mediators cytokine-induced neutrophil chemoattractant 1 (CINC-1), interleukin (IL)-6 and monocyte chemoattractant protein-1 (MCP-1) in heart and lung homogenates were measured by ELISA. Results: In both sub-strains, IH caused significant elevations of CINC-1 in heart and lung homogenates of both strains (6N heart: 113.1 ± 20.5 pg/mg protein vs. 60.5 ± 8.8 pg/mg protein for IH and IN group respectively, p < 0.05; 6J heart: 114.7 ± 10.3 pg/mg protein vs. 73.4 ± 8.7 pg/mg protein for IH and IN group respectively, p < 0.01) (6N lung: 81.7 ± 9.4 pg/mg protein vs. 57.8 ± 3.5 pg/mg protein for IH and IN group respectively, p < 0.05; 6J lung: 55.6 ± 2.7 pg/mg protein vs. 46.2 ± 2.7 pg/mg protein for IH and IN respectively, p < 0.05). However, there was a differential IH-mediated elevations of IL-6 in lung homogenates of both strains but not in heart homogenates (6N lung: 8.0 ± 0.6 pg/mg protein vs. 5.5 ± 0.5 pg/mg protein for IH and IN group respectively, p < 0.01; 6J lung: 7.5 ± 0.7 pg/mg protein vs. 5.5 ± 0.4 pg/mg protein for IH and IN respectively, p < 0.05). IH caused no difference in heart and lung MCP-1 level of either strain. Conclusion: Our data revealed that the genetic difference between 6N and 6J mice has similar impact on IH-induced cardiac and pulmonary inflammation. CINC-1 is expected to be an excellent tool for investigating neutrophil-mediated inflammatory diseases due to cardiopulmonary sequelae of obstructive sleep apnoea. †Equal contributors Acknowledgement: This study was supported by the generous donation from Shun Tak District Min Yuen Tong of Hong Kong and Stanley Ho Matching Grant
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