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Plasma Phospholipids (plasma + phospholipid)

Distribution by Scientific Domains
Chemistry70%
Medical Sciences30%

Selected Abstracts

Plasma phospholipids implicated in the matrix effect observed in liquid chromatography/tandem mass spectrometry bioanalysis: evaluation of the use of colloidal silica in combination with divalent or trivalent cations for the selective removal of phospholipids from plasma

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 18 2008
Steven T. Wu
The feasibility of the use of colloidal silica in combination with a number of divalent or trivalent cations for the removal of plasma phospholipids was evaluated by sequentially adding the two reagents (i.e., colloidal silica and a cation) directly to blank plasma samples or plasma samples spiked with analytes. Three representative plasma phospholipids were monitored to determine the efficiency of the phospholipids removal under different reagent combinations. The recovery of each spiked analyte was also monitored under each condition in order to determine if any of the analyte was removed along with the phospholipids. By optimizing the amounts of the reagents used and the sequence of the addition of the reagents, quantitative and reproducible removal of the phospholipids was achieved. Using the finally selected lanthanum cation, the removal of phospholipids was achieved with minimal concomitant loss of the ten investigated analytes which were carefully selected to incorporate functional groups that could potentially interact with the added reagents and hence could be removed along with the phospholipids. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Long-chain polyunsaturated fatty acids in a diabetic teenager during and after nine repeated episodes of diabetic ketoacidosis

PEDIATRIC DIABETES, Issue 3 2009
Éva Szabó
Abstract:, Type 1 diabetes is often accompanied with acute hypoinsulinemia that may theoretically inhibit the conversion of essential fatty acids to their longer-chain metabolites. Previously, we found significant reduction in plasma arachidonic (C20:4n-6) and docosahexaenoic (C22:6n-3) acid values in a group of diabetic children during diabetic ketoacidosis. Here we report data on the changes of fatty acids in plasma phospholipids in a diabetic teenager during and after nine subsequent episodes of diabetic ketoacidosis (DKA). Plasma phospholipid linoleic acid (C18:2n-6) values significantly decreased [23.05 (1.05) versus 19.22 (3.22), % w/w, median (IQR), p < 0.01], while values of dihomo-gamma-linolenic acid (C20:3n-6) and docosatetraenoic acid (C22:4n-6) significantly increased [1.72 (0.44) versus 1.80 (0.63) and 0.40 (0.01) versus 0.45 (0.07), respectively, p < 0.05]. Values of alpha-linolenic acid (C18:3n-3) did not change, while values of docosahexaenoic acid were significantly higher after than during the ketoacidosis [1.57 (0.67) versus 1.87 (0.32), p < 0.05). These data obtained in the same patient during repeated episodes of diabetic ketoacidosis support the concept that hypoinsulinemia plays an important role in disturbances of essential fatty acid metabolism in diabetes. [source]

Phospholipids in liquid chromatography/mass spectrometry bioanalysis: comparison of three tandem mass spectrometric techniques for monitoring plasma phospholipids, the effect of mobile phase composition on phospholipids elution and the association of phospholipids with matrix effects

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 14 2009
Yuan-Qing Xia
Because plasma phospholipids may cause matrix effects in bioanalytical liquid chromatography/tandem mass spectrometry (LC/MS/MS) methods, it is important to establish optimal mass spectrometric techniques to monitor the fate of phospholipids during method development and application. We evaluated three MS/MS techniques to monitor phospholipids using positive and negative electrospray ionization (ESI). The first technique is based on using positive precursor ion scan of m/z 184, positive neutral loss scan of 141 Da and negative precursor ion scan of m/z 153. The second technique is based on using class-specific positive and negative selected reaction monitoring (SRM) transitions to monitor class-representative phospholipids. The third technique, previously reported, utilizes in-source collision-induced dissociation (CID)-based positive SRM of m/z 184,,,184. We recommend the all-inclusive technique 1 for use in qualitative assessment of all classes of phospholipids and technique 2 for use in quantitative assessment of class-representative phospholipids. Secondly, we evaluated the elution behaviors of the plasma phospholipids under different reversed-phase mobile phase conditions. The phospholipid-eluting strength of a mobile phase was mainly dependent on the type and amount (%) of the organic eluent and the strength increased in the order of methanol, acetonitrile and isopropyl alcohol. Under the commonly used gradient and isocratic elution schemes in LC/MS/MS bioanalysis, not all the phospholipids are eluted off the column. Thirdly, we investigated the association between phospholipids and matrix effects in positive and negative ESI using basic, acidic and neutral analytes. While the phospholipids caused matrix effects in both positive and negative ESI, the extent of ionization suppression was analyte-dependent and was inversely related to the retention factor and broadness of the phospholipids peaks. The lysophospholipids which normally elute earlier in reversed-phase chromatography are more likely to cause matrix effects compared to the later-eluting phospholipids in spite of the larger concentrations of the latter in plasma. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Plasma phospholipids implicated in the matrix effect observed in liquid chromatography/tandem mass spectrometry bioanalysis: evaluation of the use of colloidal silica in combination with divalent or trivalent cations for the selective removal of phospholipids from plasma

RAPID COMMUNICATIONS IN MASS SPECTROMETRY, Issue 18 2008
Steven T. Wu
The feasibility of the use of colloidal silica in combination with a number of divalent or trivalent cations for the removal of plasma phospholipids was evaluated by sequentially adding the two reagents (i.e., colloidal silica and a cation) directly to blank plasma samples or plasma samples spiked with analytes. Three representative plasma phospholipids were monitored to determine the efficiency of the phospholipids removal under different reagent combinations. The recovery of each spiked analyte was also monitored under each condition in order to determine if any of the analyte was removed along with the phospholipids. By optimizing the amounts of the reagents used and the sequence of the addition of the reagents, quantitative and reproducible removal of the phospholipids was achieved. Using the finally selected lanthanum cation, the removal of phospholipids was achieved with minimal concomitant loss of the ten investigated analytes which were carefully selected to incorporate functional groups that could potentially interact with the added reagents and hence could be removed along with the phospholipids. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Systematic LC-MS/MS bioanalytical method development that incorporates plasma phospholipids risk avoidance, usage of incurred sample and well thought-out chromatography

BIOMEDICAL CHROMATOGRAPHY, Issue 1 2010
Mohammed Jemal
Abstract This treatise summarizes the underlying principle and the road map for systematic LC-MS/MS bioanalytical method development. The three themes that have recently emerged as central to building quality during method development,phospholipids, incurred sample and sound chromatographic considerations,are the main focus of this article. In order to reduce the bioanalytical risk associated with plasma phospholipids, a dual approach involving extraction and chromatography is recommended. The use of incurred sample during method development is essential to avoid interference arising from drug-related components. This is different from the current practice of incurred sample reanalysis, which tests reproducibility during method application. LC column/mobile phase optimization is needed to achieve appropriate peak shape, sensitivity and the separation of the analyte from interfering metabolites and phospholipids. Related to sound chromatographic considerations, we lay out facts and myths related to UPLC, vis-ŕ-vis HPLC. Incorporation of quality during method development avoids the costly experience of finding out by chance about the invalidity of a method after it has been used in support of a number of pivotal clinical and non-clinical studies. To this end, we put forth an outline of a protocol for a systematic LC-MS/MS bioanalytical method development. Copyright © 2009 John Wiley & Sons, Ltd. [source]

n-3 Fatty acid supplementation in burned paediatric patients

ACTA PAEDIATRICA, Issue 12 2009
MC Marín
Abstract Aim:, To determine the effect of dietary supplementation with n-3 fatty acids (FA) in paediatric burned patients who had less than 20% of total body surface affected. Methods:, Burned patients were randomly assigned into two groups, one of them received a supplement of n-3 FA during 5 weeks; the other group was considered as not n-3 supplemented burned group. A third group of no burned patients was selected as control. Blood samples were collected at admission and in burned groups at the final of the study. Plasma and erythrocyte phospholipid FA composition and some biochemical parameters related to the clinical evolution: total plasma proteins and C3 and C4 complement proteins were determined. Results:, In the early post-burn patients, there is an increase in saturated and monounsaturated FAs in plasma phospholipids, and a decrease in polyunsaturated FAs compared with control. These alterations are in favour of proinflammatory response to burn injury. In n-3 FA supplemented group, these changes were further reverted, and a favourable response in the amount of total plasma proteins and in C3 and C4 proteins of the complement system was demonstrated. Conclusion:, Dietary n-3 FA supplementation might be beneficial for patients suffering thermal injury. [source]

Fatty acid composition in breast milk and serum phospholipids of healthy term Chinese infants during first 6 weeks of life

ACTA PAEDIATRICA, Issue 11 2007
YM Peng
Abstract Aim: To compare the fatty acid (FA) pattern in early and mature breast milk with that in plasma phospholipids of cord blood and breast-fed infants. Methods: Forty-five mother,infant pairs from western Shanghai were studied. All infants, born at term with normal weight and length, were examined at birth and days 5 and 42. FA was analyzed by capillary gas,liquid chromatography. Results: Cord blood showed higher concentration of long-chain polyunsaturated FA (LCPUFA) but lower saturated (SFA) and monounsaturated (MUFA) FA than postnatal infants' plasma. SFA decreased with age in the infants, but MUFA and linoleic acid (LA, 18:2,6) increased. LCPUFA were lower in the plasma of 5-day-old infants than in cord blood, but LA was 80%, ,-linolenic acid (ALA, 18:3,3) 33% and the ratio ,-6/,-3 42% higher. At day 42, LA increased further, LCPUFA remained similar, and was in breast milk lower than at day 5, while ALA and ,-linolenic acid (18:3,6) were higher. The activity index of desaturases indicated high ,9 activity in breast milk and high activity of ,5 desaturase in the infants. Conclusion: Breast milk FA composition changed markedly from day 5 to 42 with increasing correlation to infants' plasma. Calculation of desaturase activities suggested high capacity of LCPUFA synthesis. [source]