Severity: Warning
Message: file_get_contents(https://...@pubfacts.com&api_key=b8daa3ad693db53b1410957c26c9a51b4908&a=1): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
Filename: helpers/my_audit_helper.php
Line Number: 176
Backtrace:
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 176
Function: file_get_contents
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 250
Function: simplexml_load_file_from_url
File: /var/www/html/application/helpers/my_audit_helper.php
Line: 3122
Function: getPubMedXML
File: /var/www/html/application/controllers/Detail.php
Line: 575
Function: pubMedSearch_Global
File: /var/www/html/application/controllers/Detail.php
Line: 489
Function: pubMedGetRelatedKeyword
File: /var/www/html/index.php
Line: 316
Function: require_once
This study demonstrates the potential utility of on-line chip-type asymmetrical flow field-flow fractionation (cAF4) and electrospray ionization tandem mass spectrometry (ESI-MS-MS) for the top-down lipidomic analysis of human lipoproteins. Utilizing a cAF4, which is a miniaturized AF4 channel operated with a micro flow rate regime, enabled high density lipoprotein (HDL) and low density lipoprotein (LDL) to be separated by hydrodynamic diameter in an aqueous solution with the simultaneous desalting of lipoproteins. On-line desalting was found to enhance the ionization of lipoproteinic lipid molecules during the feeding of cAF4 effluent to ESI-MS when compared to the direct infusion of lipoproteins to MS. An evaluation of top-down lipidomic analysis was performed to test the efficiency of in-source fragmentation during cAF4-ESI-MS in the dissociation of lipoprotein particles into individual lipid molecules. This study demonstrates the structural identification of the following lipid classes: phosphatidylcholines (PCs), cholesteryl esters (CEs), and regioisomers of triacylglycerols (TAGs) having an identical mass but different acyl chains and dimeric forms of TAGs in the positive ion mode, and phosphatidylglycerols (PGs), phosphatidic acids (PAs), phosphatidyinositols (PIs), and their lyso species in the negative ion mode. The developed method was applied to plasma samples from patients with coronary artery disease (CAD) for the separation of HDL and LDL and for the simultaneous analysis of lipoproteinic lipids, resulting in the identification of 11 PCs, 9 PGs, 4 PAs, 2 PIs, 2 PEs, 18 TAGs, and 6 CEs.
Download full-text PDF |
Source |
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http://dx.doi.org/10.1016/j.chroma.2013.01.025 | DOI Listing |
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