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61.
Chièze L Bolanos-Garcia VM Le Caër G Renault A Vié V Beaufils S 《Biochimica et biophysica acta》2012,1818(11):2732-2741
Exchangeable apolipoproteins A-I and A-II play distinct roles in reverse cholesterol transport. ApoA-I interacts with phospholipids and cholesterol of the cell membrane to make high density lipoprotein particles whereas apolipoprotein A-II interacts with high density lipoprotein particles to release apolipoprotein A-I. The two proteins show a high activity at the aqueous solution/lipid interface and are characterized by a high content of amphipathic α-helices built upon repetition of the same structural motif. We set out to investigate to what extent the number of α-helix repeats of this structural motif modulates the affinity of the protein for lipids and the sensitivity to lipid packing. To this aim we have compared the insertion of apolipoproteins A-I and A-II in phospholipid monolayers formed on a Langmuir trough in conditions where lipid packing, surface pressure and charge were controlled. We also used atomic force microscopy to obtain high resolution topographic images of the surface at a resolution of several nanometers and performed statistical image analysis to calculate the spatial distribution and geometrical shape of apolipoproteins A-I and A-II clusters. Our data indicate that apolipoprotein A-I is sensitive to packing of zwitterionic lipids but insensitive to the packing of negatively charged lipids. Interestingly, apolipoprotein A-II proved to be insensitive to the packing of zwitterionic lipids. The different sensitivity to lipid packing provides clues as to why apolipoprotein A-II barely forms nascent high density lipoprotein particles while apolipoprotein A-I promotes their formation. We conclude that the different interfacial behaviors of apolipoprotein A-I and apolipoprotein A-II in lipidic monolayers are important determinants of their distinctive roles in lipid metabolism. 相似文献
62.
63.
Shenzhong Tian Tangyuan Ning Hongxiang Zhao Bingwen Wang Na Li Huifang Han Zengjia Li Shuyun Chi 《PloS one》2012,7(12)
The objective of this study was to quantify soil methane (CH4) and nitrous oxide (N2O) emissions when converting from minimum and no-tillage systems to subsoiling (tilled soil to a depth of 40 cm to 45 cm) in the North China Plain. The relationships between CH4 and N2O flux and soil temperature, moisture, NH4
+-N, organic carbon (SOC) and pH were investigated over 18 months using a split-plot design. The soil absorption of CH4 appeared to increase after conversion from no-tillage (NT) to subsoiling (NTS), from harrow tillage (HT) to subsoiling (HTS) and from rotary tillage (RT) to subsoiling (RTS). N2O emissions also increased after conversion. Furthermore, after conversion to subsoiling, the combined global warming potential (GWP) of CH4 and N2O increased by approximately 0.05 kg CO2 ha−1 for HTS, 0.02 kg CO2 ha−1 for RTS and 0.23 kg CO2 ha−1 for NTS. Soil temperature, moisture, SOC, NH4
+-N and pH also changed after conversion to subsoiling. These changes were correlated with CH4 uptake and N2O emissions. However, there was no significant correlation between N2O emissions and soil temperature in this study. The grain yields of wheat improved after conversion to subsoiling. Under HTS, RTS and NTS, the average grain yield was elevated by approximately 42.5%, 27.8% and 60.3% respectively. Our findings indicate that RTS and HTS would be ideal rotation tillage systems to balance GWP decreases and grain yield improvements in the North China Plain region. 相似文献
64.
Zongyou Yang Wei Chen Zhidao Xia Yueju Liu Shaun Peggrem Tao Geng Zhaoxu Yang Han Li Bin Xu Chi Zhang James T. Triffitt Yingze Zhang 《PloS one》2015,10(5)
Delayed healing or non-union of skeletal fractures are common clinical complications. Ibandronate is a highly potent anti-catabolic reagent used for treatment of osteopenia and fracture prevention. We hypothesized that local application of ibandronate after fracture fixation may improve and sustain callus formation and therefore prevent delayed healing or non-union. This study tested the effect of local application of an ibandronate/gelatin sponge composite on osteotomy healing. A right-side distal-femoral osteotomy was created surgically, with fixation using a k-wire, in forty adult male rabbits. The animals were divided into four groups of ten animals and treated by: (i) intravenous injection of normal saline (Control); (ii) local implantation of absorbable gelatin sponge (GS); (iii) local implantation of absorbable GS containing ibandronate (IB+GS), and (iv) intravenous injection of ibandronate (IB i.v.). At two and four weeks the affected femora were harvested for X-ray photography, computed tomography (CT), biomechanical testing and histopathology. At both time-points the results showed that the calluses in both the ibandronate-treated groups, but especially in the IB+GS group, were significantly larger than in the control and GS groups. At four weeks the cross sectional area (CSA) and mechanical test results of ultimate load and energy in the IB+GS group were significantly higher than in other groups. Histological procedures showed a significant reduction in osteoclast numbers in the IB+GS and IB i.v. groups at day 14. The results indicate that local application of an ibandronate/gelatin sponge biomaterial improved early osteotomy healing after surgical fixation and suggest that such treatment may be a valuable local therapy to enhance fracture repair and potentially prevent delayed or non-union. 相似文献
65.
Hong Jun Choi Joo Bin Hong Jeong Joon Park Won-Jae Chi Mu-Chan Kim Yong-Keun Chang Soon-Kwang Hong 《Biotechnology and Bioprocess Engineering》2011,16(1):81-88
The agar degrading bacterial strain GNUM-08124 was isolated from Enteromorpha compressa collected in the East Sea of Korea by using a selective artificial sea water (ASW) agar plate containing agar as the sole carbon source. GNUM-08124 grows to produce a circular, smooth, yellow-colored, and raised colony. Its ability to hydrolyze agar was confirmed by staining the ASW agar plate with Lugol’s solution. In liquid culture, the cell density (A600) increased exponentially and reached a maximum level on the third day of cultivation. The specific agarase activity also increased in proportion to the cell density and reached maximum agarolytic activity on the third day. The 16S rRNA sequence of GNUM-08124 showed a close relationship to Micrococcus luteus (99.65%) and Micrococcus endophyticus (99.15%), which led us to assign it to the genus Micrococcus. Physiological studies indicated that optimal growth conditions were between 30 and 40°C, pH 4 and 7, using media containing between 5 and 10% NaCl (w/v), respectively. The GNUM-08124 strain was a grampositive, urease-positive, and catalase-positive bacterium. It could not hydrolyze gelatin, cellulose, xylan, or starch, but fermented a broader range of substrates, including Dglucose, D-galactose, D-fructose, D-lactose, D-trehalose, D-mannitol, D-melibiose, D-raffinose, D-xylose, methyl-α-D-glucopyranoside, N-acetyl-glucosamine, and xylitol, than those fermented by M. luteus or M. endophyticus, suggesting GNUM-08124 is a novel agar hydrolyzing microorganism belonging to Genus Micrococcus. Micrococcus sp. GNUM-08124 showed the highest agarase activity when it was cultured in ASW-YP medium supplemented with 0.4% glucose, but demonstrated lower activity in rich media (LB or TSB), in spite of superior cell growth, implying that agarase production is tightly regulated in an agar-dependent manner and repressed in rich conditions. 相似文献
66.
Wang CC Chu KO Chong WS Li WY Pang CP Shum AS Lau TK Rogers MS 《Free radical biology & medicine》2007,43(4):519-527
Tea is the most common beverage after water. Concerns have been raised about the safety of tea during pregnancy, especially for embryo development. We aimed at studying the effects of active tea components on developing embryos by in vitro rat embryo culture. Rat embryos during early organogenesis were cultivated in serum supplemented with one of the tea catechins. Developmental hallmarks and malformations (Mal) in the developing embryos were compared and evaluated by a standard morphological scoring system. The embryotoxicity of each tea catechin was classified according to the European Center for the Validation of Alternative Methods. Cell viability was assessed by supervital dye staining, apoptosis by TUNEL assay, and peroxidation by the 8-isoprostane EIA method. We found that (+)-catechin had the least effect on developing embryos (Mal(50)=715.1 mg/L; IC50(Mal)=435 mg/L), whereas (-)-epigallocatechin gallate had the most adverse effect (Mal(50)=54.2 mg/L; IC50(Mal)=45.8 mg/L). The major malformation in affected embryos included caudal retardation with abnormal axial flexion and delayed hind-limb formation. All catechins were classified as nonembryotoxic except (-)-epigallocatechin gallate, which was classified as weakly embryotoxic. With (-)-epigallocatechin gallate, increased numbers of nonviable and apoptotic cells in the malformed embryos were associated with increased embryo 8-isoprostane. 相似文献
67.
Effects of tetrandrine on apoptosis and radiosensitivity of nasopharyngeal carcinoma cell line CNE 总被引:1,自引:0,他引:1
68.
内蒙古多伦县土地沙漠化景观格局变化特征 总被引:2,自引:0,他引:2
利用景观分析软件Fragstats 3.3和内蒙古多伦县1960、1975、1987、1995、2000、2005年6期遥感影像解译结果,分析了1960—2005年间土地沙漠化景观格局变化.结果表明:1960—1995年间研究区土地沙漠化面积呈先增后减趋势,总沙漠化面积增加212.70km2,沙漠化斑块数先增多后减少,景观多样性和均匀性上升,轻度、中度、重度沙漠化斑块形状趋向简单;1995—2005年间研究区沙漠化斑块数大幅增加,景观多样性和均匀性下降,轻度、中度、重度沙漠化斑块形状趋向复杂;严重沙漠化斑块形状在1960年以后一直趋向复杂化.整个景观在研究期间表现为完整-破碎-完整-破碎的趋势,由轻度到严重沙漠化,其景观类型的破碎化程度逐渐降低. 相似文献
69.
Alfred Chor San Chan Qiu Qiu Siu Wai Choi Stanley Sau Ching Wong Albert Chi Yan Chan Michael G Irwin Chi Wai Cheung 《PloS one》2016,11(2)
Background
Patients receiving total intravenous anesthesia (TIVA) with propofol have been shown to experience less postoperative pain. We evaluated the post-operative analgesic effects of propofol compared with sevoflurane maintenance of anesthesia in liver surgery. This study was registered at ClinicalTrials.gov (). NCT02179437Methods
In this retrospective study, records of patients who underwent liver surgery between 2010 and 2013 were reviewed. Ninety-five patients anesthetized with propofol TIVA were matched with 95 patients anesthetized with sevoflurane. Numeric pain rating scale (NRS) pain scores, postoperative morphine consumption, side effects and patients’ satisfaction with pain relief were evaluated.Results
The TIVA group reported lower NRS pain scores during coughing on postoperative days 1 and 2 but not 3 (p = 0.0127, p = 0.0472, p = 0.4556 respectively). They also consumed significantly less daily (p = 0.001 on day 1, p = 0.0231 on day 2, p = 0.0004 on day 3), accumulative (p = 0.001 on day 1, p<0.0001 on day 2 and p = 0.0064 on day 3) and total morphine (p = 0.03) when compared with the sevoflurane group. There were no differences in total duration of intravenous patient controlled analgesia (PCA) morphine use and patient satisfaction. No difference was found in reported side effects.Conclusion
Patients anesthetized with propofol TIVA reported less pain during coughing and consumed less daily, accumulative and total morphine after liver surgery. 相似文献70.
人体和动物模型的体表物理信息地形图的研究 总被引:1,自引:0,他引:1
对人体头面、躯干、四肢、耳廓各局部几十个及整个人体等体表部位正、背面等210个部位进行超微弱冷光和温度测量,输入电子计算机,经特殊的自编程序处理,获得十分清晰的,由3000多数据构成的各个局部或人体整体的冷光和温度地形图。 对家兔左、右耳廓、胸腹部、背部都分别观察32个部位的冷光与体表温度,经计算机分析处理,每观察区域获得约由2000个数据构成的精确的冷光、温度地形分市图。并可见不同生理、病理状态及不同病程家兔体表冷光、温度等地形图呈有规律的改变。 此外,我们还编制了以体表左右相应对称部位差值为分析数据进行地形图分析的程序,用以人体和动物体表物理信息对称规律的研究。 本工作以图形的形式显示物理参量在体表的广泛的分布规律,以揭示机体内部的不同生理、病理状态。本方法定位准确、直观醒目,为研究体表信息及机体生命活动规律提供了与逐点直接测量方法相互补充的有益的新手段。 相似文献