Biomedical subjects

T Glonek

Publications and source records attributed to T Glonek.

At least 37 records · Page 2Linked to original sources

PubMed1995

Phospholipid profiling of sediments using phosphorus-31 nuclear magnetic resonance.

A phosphorus-31 nuclear magnetic resonance method has been developed for the determination of aquatic sediment phospholipid profiles that may be generally applied to all soils and deposits containing viable cellular material. A method of scrubbing chloroform/methanol extracts with potassium acid phosphate overcomes adverse signal broadening from the mineral component, permitting eleven sediment phospholipids to be determined at the quantitative level.

Chloroform↗

PubMed1995

Distribution of membrane phospholipids in the rabbit neural retina, optic nerve head and optic nerve.

Since diseases of the neural retina and optic nerve can result in alteration of biological membranes, this study determines similarities and differences in the membrane phospholipid content of the neural retina, optic nerve head, and optic nerve to serve as baseline data. Neural retina, optic nerve head, and optic nerve were dissected, isolated as 5 sets from 20 rabbits and frozen in liquid N2. Separate pooled-tissue extracts were prepared for each set of tissues and phosphorus-31 nuclear magnetic resonance (31P NMR) analyses performed. Ten phospholipids were quantified (respective neural retina, optic nerve head, and optic nerve mole % are given for the 5 major phospholipids detected): phosphatidylcholine (PC), 44.61, 27.67, 26.40; PC plasmalogen or alkylacyl PC (CPLIP); phosphatidylinositol (PI); sphingomyelin (SM); phosphatidylserine (PS), 12.63, 14.77, 15.09; phosphatidylethanolamine (PE), 21.21, 9.59, 8.69; PE plasmalogen (EPLAS), 11.07, 30.96, 33.93; an unidentified (unknown) phospholipid (U) at the chemical-shift value of 0.13 ppm; diphosphatidylglycerol (DPG); and phosphatidic acid (PA), 0.46, 2.92, 1.57. Significant differences between the various tissues were determined by the one-way analysis of variance, using a Scheffé range value of P < 0.05. The neural retina in all phospholipids detected except for the uncharacterized (unknown) phospholipid was significantly different from the optic nerve head tissue. The optic nerve head was significantly different from the optic nerve in PC, CPLIP, PE, EPLAS, U, DPG, and PA. The data provide a baseline for studies on pathologically changed neural retina, optic nerve head, and optic nerve.

Animals↗

PubMed1995

Distribution of membrane phospholipids in the rabbit uvea.

BACKGROUND AND AIMS: Since the uveal tract becomes involved in inflammatory disorders, which are known to affect lipid metabolism, we studied normal membrane phospholipids (PLs) in order to (1) determine baseline PL profiles of the iris, ciliary body, and choroid, and (2) compare and contrast PL profiles of the uveal tissues. METHODS: Iris, ciliary body and choroid tissues were isolated from rabbit eyes (n = 30) and extracted with chloroform-methanol using a modified Folch procedure. Quantitative tissue PL profiles were obtained using 31P nuclear magnetic resonance. RESULTS: Fourteen PLs were detected and quantitated in all three uveal tissues among which was one unidentified PL at -0.17 ppm. The five major PLs in the iris, ciliary body and choroid, respectively, have the following PL composition (mole percent of total phosphorus): ethanolamine plasmalogen 14.58, 15.07, 16.52; phosphatidylethanolamine 13.10, 12.40, 9.23; phosphatidylserine 11.24, 10.27, 12.13; sphingomyelin (SM) 11.10, 11.97, 18.21; and phosphatidylcholine (PC) 36.61, 36.70, 29.88. Additionally, lysophosphatidic acid, phosphatidic acid, lysophosphatidylcholine, phosphatidylinositol, and PC plasmalogen or alkacyl PC were detected in all tissues. Sphingosylphosphorylcholine also was detected in the ciliary body and choroid. Lysophosphatidylethanolamine was detected in the choroid. In addition, 42 PL metabolic indexes were calculated from these data, which permitted pathway-specific lipid analyses. CONCLUSION: This study establishes baseline PL profiles of the uveal tract tissues and will permit comparisons with tissues from eyes with inflammatory disorders. The PL concentrations in conjunction with the indexes demonstrate that overall the choroid has membranes that are less permeable to ion translocation than either the iris or the ciliary body, although there are compensatory concentration changes between the SM and PC components among these three tissues.

Animals↗

PubMed1995

Interspecies comparisons of lens phospholipids.

The purpose of this study was to compare and contrast quantitative crystalline lens phospholipid profiles among human, pig, rabbit, rat mouse, dog, lamb, guinea pig, beef, calf, chinook salmon, and golden roach. Lenses were extracted using chloroform-methanol. The extracts were prepared for phospholipid 31P NMR quantitative analysis using an NMR analytical reagent specifically designed for this purpose. Lens phospholipid profiles vary among vertebrate species. Thirteen different phospholipids [phosphatidylglycerol, lysophosphatidylethanolamine, phosphatidic acid, diphosphatidylglycerol, the ethanolamine plasmalogen (EPLAS), phosphatidylethanolamine (PE), phosphatidylserine (PS), sphingomyelin (SM), lysophosphatidylcholine, phosphatidylcholine (PC), including four uncharacterized (unknown) phospholipids at 1.31 ppm (human), 1.20 ppm (human, rabbit, dog, lamb, beef, calf), 0.13 ppm (all except rat), and -0.17 ppm (rat, beef) were detected. EPLAS, PE, PS, SM, and PC are the major lens phospholipids in all species except the human, where the major phospholipid is the unknown at 0.13 ppm. The lens content of this major unknown in mole percentage of the total detected phospholipid profile is: human 43.7; pig 6.7; rabbit, 6.1; rat (not detected); mouse, 3.2; dog, 5.0; guinea pig, 2.0; lamb, 7.0; beef, 7.7; calf, 5.6; chinook salmon, 6.7; and golden roach, 1.6. Large qualitative and quantitative differences were observed among lens species, indicating the necessity for prudent selection of appropriate animal models. The most striking finding is that no other species except the human species exhibits such a profound amount of the unknown phospholipid at 0.13 ppm. In the human lens, this phospholipid is the major phospholipid.

Animals↗

PubMed1995

The effects of age on phosphatic metabolites of the human cornea.

Phosphatic metabolites from human corneas, pooled into 7 decades ranging from ages < 1 year through 79 years, were quantitated using phosphorus-31 magnetic resonance (31P MR) spectroscopy. Relative concentrations of phosphorus-containing compounds measured included the low-energy metabolites [phosphomonoesters (PME), inorganic orthophosphate (Pi), phosphodiesters (glycerol 3-phosphorylethanolamine and glycerol 3-phosphorylcholine)] and the high-energy metabolites [phosphocreatine (PCr), adenosine triphosphate (ATP), adenosine diphosphate (ADP), nucleosidediphosphosugars and the dinucleotides]. Significant linear changes attributable to age occur in the relative mole percentage decrease of phosphate concentrations of human corneal PME, PCr and ATP, and in the increase of Pi. Age-attributable rates of decrease in PME at -0.162 MPP/YR (mole percent phosphorus per year), PCr at -0.015 MPP/YR and ATP at -0.487 MPP/YR combined, approximate the rate of increase in Pi determined to be +0.729 MPP/YR. Of the indices computed from the human corneal spectral data, the ratios of ATP/Pi and PME/Pi and the tissue energy modulus were all found to decrease significantly with age. These changes in corneal phosphatic metabolites are indicative of an overall decline in high-energy metabolism with age.

Adolescent↗

PubMed1995

Comparison of relative changes in phosphatic metabolites and phospholipids after irradiation.

Measurements of phosphatic metabolites and phospholipids using 31P NMR spectroscopy were performed on tumor extracts at specific times before and after a priming dose of radiation at 32 or 65 Gy. At both doses, statistically significant increases in the high-energy phosphates PCr and ATP, relative to their primary hydrolysis product Pi, were detected at 24 h after irradiation. These spectral changes are consistent with an increased capacity for aerobic metabolism and oxidative phosphorylation. The changes coincide with a significant reduction in the hypoxic cell fraction and 50% tumor control dose measurements reported previously for the same tumor model. A significant increase in the ratio of phosphorylethanolamine to phosphorylcholine was also detected at 24 h. The ratio of ethanolamine-containing to choline-containing phospholipids increased significantly between 48 and 96 h. The spectral changes measured in this study coincide with the changes in the hypoxic state of the tumor after irradiation and are consistent with spectral measurements performed in vivo. The high-resolution spectroscopic data also identify specific metabolites contributing to spectral changes measured in vivo.

Animals↗

PubMed1994

31P NMR phospholipid characterization of intracranial tumors.

Phospholipid extracts from 48 intracranial tumors were analyzed using 31P NMR. Phospholipids commonly identified in the tumor spectra included phosphatidylglycerol (PG), phosphatidic acid (PA), diphosphatidylglycerol (DPG), uncharacterized phospholipid (U), ethanolamine plasmalogen (EPLAS), phosphatidylethanolamine (PE), phosphatidylserine (PS), sphingomyelin (SM), lysophosphatidylcholine (LPC), phosphatidylinositol (PI), a choline phospholipid (CPLIP), and phosphatidylcholine (PC). Differences in the mean relative mole-percentage of phosphorus concentrations of individual phospholipids were used to differentiate among tumors. Neural sheath tumors (neurilemmoma, neurofibroma and fibrosarcoma) were noted to contain significantly elevated levels of SM relative to tumors of neural glial origin and individually, glioblastoma multiforme was noted to contain depressed levels of SM relative to neurilemmoma, neurofibroma and meningioma. Significantly decreased levels of PA were noted for glioblastoma relative to neurilemmoma along with significantly decreased levels of PE relative to meningioma. Elevated levels of LPC and CPLIP were seen in glioblastoma multiforme relative to meningioma. Additional findings included elevated levels of PC for glioblastoma multiforme relative to neurofibroma, and neurilemmoma was differentiated from neurofibroma with elevated levels of PA and depressed levels of PI. 31P NMR phospholipid analysis provides supplemental biochemical information which may be used to improve the interpretation of spectra acquired in vivo, and reveals important tumor-specific biochemical information which may further improve the understanding of the biological behavior of intracranial tumors.

Brain Chemistry↗

PubMed1994

Meningioma phospholipid profiles measured by 31P nuclear magnetic resonance spectroscopy.

Fourteen cases of intracranial meningioma were characterized after chloroform/methanol extraction by 31P nuclear magnetic resonance (NMR) spectroscopy at 202.4 MHz. Each phospholipid class detected in the extracts was identified and quantitated in terms of its molar percentage relative to the total phospholipids measured. The following phospholipids were assayed by 31P NMR: phosphatidylglycerol, phosphatidic acid, diphosphatidylglycerol, ethanolamine plasmalogen, phosphatidylethanolamine (PE), lysophosphatidylinositol, phosphatidylserine, sphingomyelin, lysophosphatidylcholine (LPC), phosphatidylinositol (PI), sphingosylphosphorylcholine and phosphatidylcholine. In addition, two unidentified phospholipids were detected with resonances at 0.13 and -0.78 ppm, respectively. Three distinct types of spectra were obtained on the extracts and grouped accordingly for comparison purposes. Type 1 tumors showed unusual 31P NMR profiles with low levels of PE and PI and elevated levels of LPC; type 2 tumors were characterized by low levels of the ethanolamine phospholipids and near equivalent levels of PI and LPC. The spectra of type 1 and type 2 tumors were characteristic of degenerative cells that lacked membrane permeability associated with loss of ethanolamine plasmalogen in the presence of significant phospholipid turnover. Meningiomas belonging to the third spectral type showed characteristics similar to those of normal tissues with normal levels of PE and ethanolamine plasmalogen, as well as very low levels of LPC relative to PI. Type 3 tumors lacked the characteristic signs of degeneration noted in type 1 and type 2 tumors. The data corroborate and augment in vivo spectroscopic findings reported earlier and demonstrate the value of 31P NMR spectroscopic phospholipid analysis on lipid extracts for the characterization of meningiomas.

Humans↗

PubMed1994

The effect of hEGF and insulin on corneal metabolism during Optisol storage.

We examined the effect of the growth factors, human epidermal growth factor (hEGF) and insulin, on corneal metabolism during storage in Optisol, a chondroitin-sulfate-(CS)-based storage medium. Paired cat corneas, in either Optisol only or Optisol with growth factor(s), were analyzed using ex vivo 31P nuclear magnetic resonance, after storage for 1 week at 4 degrees C. Lysosomal enzyme release into the media at the end of the storage period also was measured fluorometrically. Both epithelial-intact and epithelial-denuded corneal pairs were examined for all conditions. Considering corneas having either intact epithelia or epithelium-denuded corneas, the addition of either growth factor alone to Optisol did not alter the relative corneal concentrations of five of the six phosphatic metabolite spectral bands measured or two metabolic ratios calculated from these bands. Phosphodiesters, however, were significantly lower in corneas stored in Optisol containing both hEGF and insulin (23%) than in corneas stored in Optisol alone (30%). Intracorneal pH was unaffected by the addition of growth factor(s). A significantly higher release of alpha-glucosidase and alpha-mannosidase was noted in those corneas stored in Optisol containing both hEGF and insulin. Optisol maintains high-energy phosphate corneal metabolism similar to other CS-based media, K-Sol and Chondroitin Sulfate Corneal Storage Medium (CSM). The addition of the growth factors hEGF and insulin to Optisol alters corneal metabolic activity during storage in a manner indicative of conserving corneal phospholipids.

Animals↗

PubMed1994

Tear film lipid layer thickness as a function of blinking.

Alterations in the tear film lipid layer as a function of blinking were investigated using a custom-designed specular reflection monitoring system. The tear film lipid layer of 104 subjects under conditions of normal ("baseline") blinking and "forceful" blinking was quantitated on the basis of specific interference colors. Deliberate, forceful blinking was found to significantly increase the lipid layer thickness (LLT) of the tear film. The magnitude of increase was found to be correlated with the baseline LLT values; individuals with baseline LLT values of 75-150 nm demonstrated a mean increase in LLT of 33 nm following forceful blinking, whereas subjects with baseline LLT values < or = 60 nm experienced a mean increase of 19 nm. The difference in the magnitude of increase between the groups was highly significant (p = 0.0001). The data suggest that, in addition to playing a role in the spreading of lipid across the tear film, the blinking mechanism may be important in the maintenance of the lipid layer by augmenting the expression of lipids from the meibomian glands.

Adolescent↗

PubMed1994

Phospholipid analysis of mammalian optic nerve tissue: a 31P nuclear magnetic resonance spectroscopic study.

Phospholipids of optic nerve (n = 30) from 5.6-kg rabbits were analyzed by 31P nuclear magnetic resonance (NMR) spectroscopy. Phospholipid metabolites detected were as follows (mol %): phosphatidylcholine (PC; 25.82 +/- 0.12), PC plasmalogen/alkylacyl PC (2.07 +/- 0.13), sphingosylphosphorycholine (1.12 +/- 0.20), phosphatidylinositol (PI; 2.17 +/- 0.21), lyso PC (0.85 +/- 0.06), sphingomyelin (12.52 +/- 0.10); phosphatidylserine (PS; 14.38 +/- 0.11), phosphatidylethanolamine (8.98 +/- 0.11), ethanolamine plasmalogen (28.99 +/- 0.30), unidentified phospholipid (1.10 +/- 0.01), phosphatidic acid (PA; 1.72 +/- 0.06), and lyso PS (0.28 +/- 0.10). The bulk of the ethanolamine phosphatide is in the form of its plasmalogen, which is the major phospholipid detected. The choline plasmalogen, or a reduced derivative thereof, also is present; thus, a significant phospholipid biosynthetic pathway for optic nerve tissue involves the plasmalogen route, which is a pathway distinct from the PA route responsible for the synthesis of PS, PI, and PC. This new 31P NMR lipid analytical technique offers potential for studying optic nerve phospholipid metabolism and degenerating optic nerve tissue, since the technique can accurately quantitate (1) both plasmalogen and nonplasmalogen phospholipids, (2) minor phospholipid components, and (3) previously undetected phospholipids.

Animals↗

PubMed1994

Distribution of membrane phospholipids in the crystalline lens.

PURPOSE: To determine the phospholipid content of specific anatomic regions within the crystalline lens. METHODS: Phospholipid extracts of tissues dissected from 5 sets of 10 rabbit lenses were analyzed by 31P nuclear magnetic resonance spectroscopy. Twenty-nine pathway-specific metabolic indexes were calculated from groups of phospholipids and ratios of phospholipids. RESULTS: Phospholipid levels (mole percent) were determined from the capsule with attached epithelium, the cortex, and the nucleus. Eleven phospholipids were detected with significant regional differences in the lens phospholipid profiles. The levels of phosphatidylcholine (PC), PC plasmalogen-alkylacyl PC, phosphatidylinositol (PI), phosphatidylethanolamine (PE), and diphosphatidylglycerol (DPG), and of the lyso derivatives (lyso PC and lyso PE) were greater in the capsule plus epithelium than in the cortex or the nucleus. Levels of sphingomyelin, phosphatidylserine, and PE plasmalogen (EPLAS) were less in the capsule plus epithelium than in the cortex or the nucleus. PC, PC plasmalogen-alkylacyl PC, EPLAS, and lyso PE had nearly equal amounts in the cortex and the nucleus. PI, lyso PC, and DPG could not be detected in the nucleus. DPG was only detected in the capsule plus epithelium. An unidentified phospholipid at 0.13 ppm was approximately equal in the cortex and the nucleus, but it could not be detected in the capsule plus epithelium. CONCLUSIONS: These differences demonstrate a significant heterogeneity among these anatomic regions of the lens, and differences in the nucleus relative to other regions studied are consistent with those in membranes that less readily undergo transitions from the relatively impermeable lamellar phase to the more permeable hexagonal HII phase.

Animals↗

PubMed1993

Algal phospholipids by 31P NMR: comparing isopropanol pretreatment with simple chloroform/methanol extraction.

1. A modified Folch procedure [potassium (ethylenedinitrilo)-tetraacetic acid at pH 6 substituted for KCl] is suitable for the extraction of marine algae. 2. The quantitative 31P nuclear magnetic resonance phospholipid profiles of four marine algae, Gracilaria verrucosa, Bryothamnion triquetrum, Padina gymnospora, and Caulerpa sertularioides, were obtained from Folch and Nichols extractions of both fresh and dried algae, and essentially identical results were obtained using either extraction procedure. 3. Extracts of air-dried algae are statistically different when compared to extracts of living algae, suggesting that tissue handling is a critical factor in phospholipid extractions.

1-Propanol↗

PubMed1993

Effects of exercise training and anabolic steroids on plantaris and soleus phospholipids: a 31P nuclear magnetic resonance study.

1. The purpose of this study was to examine the effect of exercise, anabolic steroid treatment, and a combination of both treatments on the phospholipid composition of predominantly fast twitch (plantaris) and slow twitch (soleus) skeletal muscles. The 4 experimental groups analyzed were sedentary control (C), steroid-treated (S), exercise-trained (E), and exercise plus steroid-treated (ES). 2. Among the 11 phospholipids quantitated, for the plantaris muscle, phosphatidylcholine was reduced in ES relative to C, while phosphatidylethanolamine and phosphatidylethanolamine plasmalogen were elevated in E and ES relative to C. For the soleus muscle, phosphatidylserine was reduced in S and E relative to C, and cardiolipin was elevated in E relative to C. 3. Of the 27 metabolic indices calculated for the plantaris, 15 changed significantly among E and ES relative to S and C, while for the soleus, only three indices changed among the four groups, two among E and ES relative to S and C and one between S and C. 4. For the plantaris muscle, the results are consistent with an exercise-induced alteration of membrane phospholipid composition that increases ion translocation activity. For the soleus muscle, this membrane alteration essentially does not take place. 5. Steroid treatment had little to no statistically significant effect on plantaris and soleus muscle phospholipid systems, regardless of the imposed regimen.

Anabolic Agents↗

PubMed1993

Effects of anabolic steroids and endurance exercise on cardiac performance.

This study examined the effects of anabolic steroids and exhaustive endurance exercise, and the combination of both treatments on in vitro cardiac contractile function. Fifty-two male Sprague-Dawley rats were randomly assigned, in groups of 13, to one of the four groups: sedentary control (C), steroid-treated (ST), exercise-trained (E), and exercise plus steroid treated (E+S). Nandrolone decanoate was administered to the steroid-treated groups every 7-9 days during the 10 weeks study, while the C and E groups received glycerol injection on these occasions. The exercised rats ran on a treadmill wearing a collar weight (2-3% of body weight) for 50 min, 5 days a week. In vitro ventricular performance was assessed in isolated Langendorff perfused hearts in response to increasing left ventricular balloon volumes. Left ventricular +dP/dt, dP/dt at 60 mmHg developed pressure, tension time index, and Emax (slope of the pressure-volume curves) were significantly (p < 0.05) lowered in the E+S group, as compared to the C, E, or ST group. Meanwhile, the E group exhibited a higher (p < 0.05) left ventricular systolic pressure (LVSP) than the C and E+S groups. No significant differences in dP/dt/P, heart weight (wt), and heart wt to body wt ratio were detected among the four groups. Rats subjected to endurance exercise or anabolic steroid treatment alone exhibited no change in LV function.(ABSTRACT TRUNCATED AT 250 WORDS)

Anabolic Agents↗

PubMed1993

Metabolic compatibility of abattoir and human corneas: an ex vivo 31P nuclear magnetic resonance spectroscopic study of intact tissues.

This study establishes the metabolic similarities and differences of intact abattoir corneas and the human cornea ex vivo, using 31P nuclear magnetic resonance spectroscopy. Phosphorylated sugars (SP), inorganic orthophosphate (Pi), phosphodiesters, ATP, ADP, and the nucleoside diphosphosugars and dinucleotides (NS&DN) were quantitated. The intracorneal pH also was determined. In addition, metabolic indices ATP/Pi, ATP/ADP, ATP/(ADP + Pi), SP/Pi, the phosphorylation potential, and the 31P energy modulus were calculated. Significant differences were observed between the abattoir and human corneas in phosphorylated sugars, NS&DN, and intracorneal pH, as well as in the indices ATP/ADP and SP/Pi. The overall energy status as measured by the 31P energy modulus was significantly higher in the bovine cornea when compared to the porcine and human corneas, suggestive of a very high energy reserve in the bovine cornea.

Adenosine Diphosphate↗

PubMed1992

Phosphodiesters in saponified extracts of human breast and colon tumors using 31P magnetic resonance spectroscopy.

Saponified phospholipid extracts of malignant and normal human breast and colon surgical tissue specimens (n = 45) generate characteristic phosphodiester profiles using 31P magnetic resonance (MR) spectroscopy. The resultant 31P MR spectroscopic profiles of the analyzed tissues are used to differentiate malignant from normal. The appearance of an uncharacterized resonance at 0.29 delta in the malignant tissue spectra (50% of breast and 75% of colon specimens) is the most notable qualitative finding. Quantitatively, malignant colon tissues differ from normal colon tissues with depressed levels of phosphatidylserine and elevated levels of glycerol 3-phosphorylglycerol and an index measuring the summation of phospholipid polar head group residues with free hydroxyl groups. Malignant breast tissues have significantly elevated levels of glycerol 3-phosphorylethanolamine and significantly depressed levels of glycerol 3-phosphorylcholine compared to normal breast tissues, reflecting a perturbation in the balance of lipid residues that are the respective breakdown products of phosphatidylethanolamine and phosphatidylcholine. The concentration of the polar head group residues is compared to 31P MR spectroscopic profiles of colon and breast tissue phospholipids, in order to demonstrate the quantitative nature of the technique employed.

Adenocarcinoma↗

PubMed1992

31P NMR of tissue phospholipids: competition for Mg2+, Ca2+, Na+ and K+ cations.

Phosphatidylcholine (PC), phosphatidylethanolamine (PE), ethanolamine plasmalogen (EPLAS), sphingomyelin (SPH), phosphatidylinositol (PI), phosphatidylserine (PS), cardiolipin (CL), phosphatidylglycerol (PG) and phosphatidic acid (PA) were dispersed together in Cs(ethylenedinitrilo)tetraacetic acid-scrubbed chloroform/methanol solution, and high resolution 31P nuclear magnetic resonance spectra were recorded. In separate titration experiments, Mg2+ and Ca2+ were added to the dispersed phospholipid mixture to determine the relative interaction potentials of each of the phospholipids for each of the added cations. The association of cations with individual phospholipids was indicated by 31P chemical-shift changes, signal broadening, signal quenching or a combination of these. The titrations revealed that CL had the highest, and PA the next highest, interaction potential for Mg2+ cations. In contrast, PS and PA had the highest, and CL the next highest, interaction potential for Ca2+. Considering only interactions with Ca2+ ions, the phospholipids can be divided into three distinct groups: PS and PA (high interaction potential); CL, PI and PG (intermediate interaction potential); and EPLAS, PE, SPH and PC (essentially no interaction potential). The two phospholipids with the least interaction potential for either of the alkaline-earth cations were PC and SPH. Na+ and K+ ion interactions with PA, CL, PI and PG were unique and resulted in positive chemical-shift changes relative to the chemical shifts in the presence of Cs+ ions. Relative to both Cs+ and K+ ions, chemical shifts in the presence of Na+ ions were deshielded delta greater than 0.1 ppm in the order PA greater than CL greater than PI greater than PG.

Binding, Competitive↗