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排序方式: 共有594条查询结果,搜索用时 31 毫秒
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Prabhakaran MP Venugopal JR Chyan TT Hai LB Chan CK Lim AY Ramakrishna S 《Tissue engineering. Part A》2008,14(11):1787-1797
Bridging of nerve gaps after injury is a major problem in peripheral nerve regeneration. Considering the potential application of a bio-artificial nerve guide material, polycaprolactone (PCL)/chitosan nanofibrous scaffolds was designed and evaluated in vitro using rat Schwann cells (RT4-D6P2T) for nerve tissue engineering. PCL, chitosan, and PCL/chitosan nanofibers with average fiber diameters of 630, 450, and 190 nm, respectively, were fabricated using an electrospinning process. The surface chemistry of the fabricated nanofibers was determined using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Simple blending of PCL with chitosan proved an easy and efficient method for fabricating PCL/chitosan nanofibrous scaffolds, whose surface characteristics proved more hydrophilic than PCL nanofibers. Evaluation of mechanical properties showed that the Young's modulus and strain at break of the electrospun PCL/chitosan nanofibers were better than those of the chitosan nanofibers. Results of cell proliferation studies on nanofibrous scaffolds using 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium assay showed 48% more cell proliferation on PCL/chitosan scaffolds than on PCL scaffolds after 8 days of culture. PCL/chitosan scaffolds showed better cell proliferation than PCL scaffolds and maintained their characteristic cell morphology, with spreading bipolar elongations to the nanofibrous substrates. This electrospun nanofibrous matrix thus proved of specific interest in tissue engineering for peripheral nerve regeneration. 相似文献
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Ghasemi-Mobarakeh L Prabhakaran MP Morshed M Nasr-Esfahani MH Ramakrishna S 《Biomaterials》2008,29(34):4532-4539
Nerve tissue engineering is one of the most promising methods to restore nerve systems in human health care. Scaffold design has pivotal role in nerve tissue engineering. Polymer blending is one of the most effective methods for providing new, desirable biocomposites for tissue-engineering applications. Random and aligned PCL/gelatin biocomposite scaffolds were fabricated by varying the ratios of PCL and gelatin concentrations. Chemical and mechanical properties of PCL/gelatin nanofibrous scaffolds were measured by FTIR, porometry, contact angle and tensile measurements, while the in vitro biodegradability of the different nanofibrous scaffolds were evaluated too. PCL/gelatin 70:30 nanofiber was found to exhibit the most balanced properties to meet all the required specifications for nerve tissue and was used for in vitro culture of nerve stem cells (C17.2 cells). MTS assay and SEM results showed that the biocomposite of PCL/gelatin 70:30 nanofibrous scaffolds enhanced the nerve differentiation and proliferation compared to PCL nanofibrous scaffolds and acted as a positive cue to support neurite outgrowth. It was found that the direction of nerve cell elongation and neurite outgrowth on aligned nanofibrous scaffolds is parallel to the direction of fibers. PCL/gelatin 70:30 nanofibrous scaffolds proved to be a promising biomaterial suitable for nerve regeneration. 相似文献
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2016 Dietary Salt Fact Sheet and Call to Action: The World Hypertension League,International Society of Hypertension,and the International Council of Cardiovascular Prevention and Rehabilitation 下载免费PDF全文
Norm R. C. Campbell MD FRCPC Daniel T. Lackland DrPH Mark L. Niebylski PhD MBA MS Marcelo Orias MD Kimbree A. Redburn MA Peter M. Nilsson MD PhD Xin‐Hua Zhang MD PhD Louise Burrell MD MBChB MRCP FRACP Masatsugu Horiuchi MD PhD FAHA Neil R. Poulter MBBS MSc FRCP FMed Sci Dorairaj Prabhakaran MD DM MSc FRCP FNASc Agustin J. Ramirez MD PhD Alta E. Schutte PhD MSc Rhian M. Touyz MBBCh PhD FRCP FRSE Ji‐Guang Wang MD PhD Michael A. Weber MD 《Journal of clinical hypertension (Greenwich, Conn.)》2016,18(11):1082-1085
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Shannon B. Donnola Elliott C. Dasenbrook David Weaver Lan Lu Karishma Gupta Anjali Prabhakaran Xin Yu James F. Chmiel Kimberly McBennett Michael W. Konstan Mitchell L. Drumm Chris A. Flask 《Journal of cystic fibrosis》2017,16(2):283-290
Background
Previous studies have shown that Magnetic Resonance Imaging (MRI) techniques can be used to non-invasively assess lung disease in CF patients. In this study, we compare the sensitivity of normalized T1 (nT1) and non-contrast perfusion MRI techniques to detect regional lung disease in CF patients.Materials and methods
MRI data were obtained for eight adult CF patients without overt pulmonary exacerbation (FEV1 = 45–127%) and six healthy volunteers on a Siemens Espree 1.5 T MRI scanner. Sagittal nT1 and perfusion data were acquired for each subject's left and right lungs. A region-of-interest analysis was used to calculate mean nT1 and perfusion values in the individual lobes of the left and right lungs for each subject.Results
In comparison to healthy controls, CF subjects showed a significant decrease in nT1 values in the upper lobe of the left lung as well as in the upper and anterior lobes of the right lung (p < 0.001). Similar nT1 differences were observed with in the CF cohort in comparison to their respective posterior lobes (p < 0.001). Pulmonary perfusion for the CF subjects was also significantly reduced in the upper lobe of the right lung (p < 0.05). Significant correlations with spirometry were also observed for both nT1 (left upper lobe: p < 0.01) and perfusion (left and right upper lobes (p ≤ 0.05)). Additionally, significant correlations were observed between nT1 and perfusion in the upper lobes of the left (p = 0.05) and right lungs (p = 0.005). Conclusions: This pilot study confirms that both the nT1 and non-contrast perfusion MRI techniques can sensitively detect regional lung changes in patients with CF. While both imaging methods were able to detect regional lung disease, the additional nT1 reductions in the CF patients suggests that nT1 may be more sensitive to regional CF lung disease. 相似文献100.
Benzalkonium Chloride: A Bronchoconstricting Preservative in Continuous Albuterol Nebulizer Solutions 下载免费PDF全文
For convenience, many pediatric hospitals are preparing solutions for continuous nebulized albuterol using the 0.5% 20‐ml multidose albuterol dropper bottle. This product contains benzalkonium chloride (BAC) that, by itself, produces bronchospasm that is dose dependent and cumulative. The bronchoconstrictive effects of BAC are greater in patients with more severe airway obstruction and increased airway responsiveness. Use of BAC‐containing albuterol during severe acute asthma exacerbations may antagonize the bronchodilator response to albuterol, prolong treatment, and increase the risk of albuterol‐related systemic adverse effects. Such a deleterious effect of BAC is difficult to detect because some patients improve slowly or may even worsen during treatment. We recommend that only preservative‐free albuterol products be used. 相似文献