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Simon D Taylorrobinson - One of the best experts on this subject based on the ideXlab platform.
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proton and Phosphorus 31 nuclear magnetic resonance spectroscopy of human bile in hepatopancreaticobiliary cancer
European Journal of Gastroenterology & Hepatology, 2005Co-Authors: Shahid A Khan, Jane I Cox, Andrew V Thillainayagam, Devinder S Bansi, H C Thomas, Simon D TaylorrobinsonAbstract:Objective Hepatopancreaticobiliary cancers can be difficult to diagnose. Nuclear magnetic resonance (NMR) spectroscopy provides non-invasive information on phospholipid metabolism, and previous studies of liver tissue have highlighted changes in phospholipids in malignancy. We hypothesised that in-vitro NMR spectroscopy of human bile may provide independent diagnostic indices in cancer management through an assessment of the phospholipid content. Design and methods Bile samples from 24 patients were collected at endoscopic retrograde cholangiopancreatography and from one subject at cholecystectomy. Thirteen patients had cancer: pancreatic carcinoma (eight), cholangiocarcinoma (three) and metastatic liver disease (two). The remaining 12 patients had non-malignant pathology. In-vitro proton ( 1 H) and Phosphorus-31 ( 31 P) NMR spectra were obtained from all samples using an 11.7 Tesla NMR spectroscopy system. Results Complementary information was obtained from the 1 H and 31 P NMR spectra. Signals were assigned to phosphatidylcholine in both 1 H and 31 P NMR spectra. Phosphatidylcholine levels were significantly reduced in the bile from cancer patients when compared with bile from non-cancer patients (P=0.007). Conclusion These preliminary studies suggest that 1 H and 31 P NMR spectroscopy of bile may be used to detect differences in phospholipid content between cancer and non-cancer patients. This may have implications for the development of novel diagnostic strategies in hepatopancreaticobiliary cancers. Further larger-scale studies are warranted.
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cerebral proton and Phosphorus 31 magnetic resonance spectroscopy in patients with subclinical hepatic encephalopathy
Liver, 1999Co-Authors: Simon D Taylorrobinson, Kumar K Changani, Humphrey Hodgson, Camilla Buckley, Jimmy D BellAbstract:Background/Aims: In vivo magnetic resonance spectroscopy can be used to study cerebral metabolism non-invasively. We aimed to correlate 1H and 31P magnetic resonance spectral abnormalities in the brains of patients with subclinical hepatic encephalopathy. Methods: Eighteen patients were studied at 1.5T, with combined 1H and 31P magnetic resonance spectra obtained from multiple voxels in the cerebral cortex and basal ganglia. Peak area ratios of choline, glutamine/glutamate, relative to creatine in the 1H spectra and percentage phosphomonoesters, phosphodiesters and ?NTP signals relative to total 31P signals in the 31P spectra were measured. Results: Six patients did not complete the full examination –31P results are available from 12 patients only. Relative to creatine, there were reductions in choline and elevations in glutamine/glutamate, varying across the brain with choline significantly reduced in occipital cortex (p<0.05) and glutamine/glutamate most significantly elevated in temporo-parietal cortex (p<0.0001). Percentage phosphomonoester (p<0.05), phosphodiester (p<0.05) and ?NTP (p<0.005) signals were significantly decreased in basal ganglia spectra. No correlation was found between the magnitude of 1H and 31P MRS changes, except between percentage phosphodiester decrease and glutamine/glutamate to creatine increase in occipital cortex. Conclusion: The results of this study point to a multifactorial aetiology for this condition.
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in vivo and in vitro hepatic Phosphorus 31 magnetic resonance spectroscopy and electron microscopy in chronic ductopenic rejection of human liver allografts
Gut, 1998Co-Authors: Simon D Taylorrobinson, J Sargentoni, Jimmy D Bell, E L Thomas, C D Marcus, Kumar K Changani, N Saeed, Humphrey Hodgson, B R Davidson, A K BurroughsAbstract:Background —In vivo hepatic Phosphorus-31 magnetic resonance spectroscopy (MRS) provides non-invasive information about phospholipid metabolism. Aims —To delineate MRS abnormalities in patients with chronic ductopenic rejection (CDR) and to characterise spectral changes by in vitro MRS and electron microscopy. Patients and methods —Sixteen liver transplant recipients (four with CDR; 12 with good graft function) and 29 controls (23 healthy volunteers; six patients with biliary duct strictures) were studied with in vivo 31 P MRS. Peak area ratios of phosphomonoesters (PME) and phosphodiesters (PDE), relative to nucleotide triphosphates (NTP) were measured. In vitro MRS and electron microscopy were performed on biopsy specimens from five patients with CDR, freeze clamped at retransplantation. Phosphoethanolamine (PE), phosphocholine (PC), glycerophosphorylethanolamine (GPE), and glycerophosphorylcholine (GPC) concentrations were measured. Results —The 12 patients with good graft function displayed no spectral abnormalities in vivo; the four patients with CDR showed significantly elevated PME:NTP (p Conclusions —The increase in PME:NTP reflects altered phospholipid metabolism in patients with CDR, while the increase in PDE:NTP may represent a significant contribution from bile phospholipid.
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effect of functional grade and etiology on in vivo hepatic Phosphorus 31 magnetic resonance spectroscopy in cirrhosis biochemical basis of spectral appearances
Hepatology, 1995Co-Authors: David K Menon, Simon D Taylorrobinson, J Sargentoni, Jimmy D Bell, I J Cox, D J Bryant, Glyn A Coutts, K Rolles, Andrew K BurroughsAbstract:Hepatic Phosphorus-31 magnetic resonance spectroscopy (31P MRS) was undertaken in 85 patients with histologically proven cirrhosis of varying etiologies and functional severity. Reference data were acquired from 16 healthy volunteers who had no history or evidence of liver disease or alcohol abuse. In vivo hepatic 31P MR spectra were acquired with pulse angle 45 degrees and repetition times (TR) of 5 and 0.5 seconds. Peak area ratios of phosphomonoesters (PME), inorganic phosphate (Pi), and phosphodiesters (PDE) relative to beta ATP, and of PME relative to PDE were calculated from spectra acquired at TR 5 seconds. Estimates of saturation effects for individual resonances were obtained by dividing the peak height at TR 5 seconds by that at TR 0.5 seconds to yield a T1-related signal height ratio (SHR). When compared with reference values, the patients with liver disease showed a significantly higher PME/ATP (P < .0001), PME/PDE (P < .0001), PME SHR (P < .001), and Pi SHR (P < .02), and a lower PDE/ATP (P < .001) and PDE SHR (P < .001). The magnitude of these changes increased significantly and progressively with increasing functional impairment. In patients with compensated cirrhosis spectral appearances varied with etiology; thus, patients with postviral cirrhosis showed a significantly higher Pi/ATP; those with alcoholic cirrhosis, a significantly lower PDE/ATP; and those with cirrhosis secondary to primary sclerosing cholangitis, a significantly lower Pi/ATP than the healthy volunteers or other etiological groups. However, spectral appearances did not vary with etiology in patients with decompensated disease. In vitro 31P MRS of perchloric extracts of samples of liver tissue obtained from 10 patients with cirrhosis at transplant hepatectomy showed increases in levels of the soluble PME metabolites, phosphorylcholine and phosphorylethanolamine, and reductions in the levels of the soluble PDE metabolites, glycerophosphorylcholine and glycerophosphorylethanolamine. These changes suggest regenerative activity in cirrhotic livers. The increases in soluble phosphomonoesters in the aqueous extracts accounted for the increased PME/ATP ratio seen in the in vivo spectra, and might account for the increase in PME SHR. The reduction in soluble phosphodiesters in the aqueous extracts did not entirely account for the reduction PDE/ATP ratio seen in vivo.(ABSTRACT TRUNCATED AT 400 WORDS)
Jerome L Ackerman - One of the best experts on this subject based on the ideXlab platform.
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evaluation of bone mineral density using three dimensional solid state Phosphorus 31 nmr projection imaging
Calcified Tissue International, 1998Co-Authors: Jerome L Ackerman, D A Chesler, Robert M Neer, Jinxi Wang, Melvin J GlimcherAbstract:A solid state magnetic resonance imaging technique is used to measure true three-dimensional mineral density of synthetic hydroxyapatite phantoms and specimens of bone ex vivo. The Phosphorus-31 free induction decay at 2.0 T magnetic field strength is sampled following application of a short, hard radiofrequency excitation pulse in the presence of a fixed amplitude magnetic field gradient. Multiple gradient directions covering the unit sphere are used in an efficient spherical polar to Cartesian interpolation and Fourier transform projection reconstruction scheme to image the three-dimensional distribution of Phosphorus within the specimen. Using 3–6 Gauss/cm magnetic field gradients, a spatial resolution of 0.2 cm over a field of view of 10 cm is achieved in an imaging time of 20–35 minutes. Comparison of solid state magnetic resonance imaging with dual energy X-ray absorptiometry (DXA), gravimetric analysis, and chemical analysis of calcium and Phosphorus demonstrates good quantitative accuracy. Direct measurement of bone mineral by solid state magnetic resonance opens up the possibility of imaging variations in mineral composition as well as density. Advantages of the solid state magnetic resonance technique include avoidance of ionizing radiation; direct measurement of a constituent of the mineral without reliance on assumptions about, or models of, tissue composition; the absence of shielding, beam hardening, or multiple scattering artifacts; and its three-dimensional character. Disadvantages include longer measurement times and lower spatial resolution than DXA and computed tomography, and the inability to scan large areas of the body in a single measurement, although spatial resolution is sufficient to resolve cortical from trabecular bone for the purpose of measuring bone mineral density.
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solid state Phosphorus 31 magnetic resonance imaging of bone mineral
Magnetic Resonance in Medicine, 1995Co-Authors: James R Moore, Leoncio Garrido, Jerome L AckermanAbstract:Chemically selective solid state Phosphorus-31 nuclear magnetic resonance (NMR) imaging of the mineral phase of bone and synthetic calcium phosphate models for bone mineral is demonstrated with microscopy-scale (about 5 mm field of view) apparatus at 6.0 T magnetic field strength. Pixel-by-pixel linear combination of image data from multiple radio frequency (RF) pulse sequences, chosen to develop contrast between chemical constituents of interest in the mineral, generates derived images showing the distribution of individual constituents. The technique combines the noninvasive character of magnetic resonance imaging (MRI) with the ability of solid state NMR spectroscopy to characterize subtle chemical variations in bone mineral, as well as to measure the amount of mineral. These methods are, in principle, extensible to larger dimensional scales suitable for live animal subjects or human limbs.
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a unique protonated phosphate group in bone mineral not present in synthetic calcium phosphates identification by Phosphorus 31 solid state nmr spectroscopy
Journal of Molecular Biology, 1994Co-Authors: Yaotang Wu, Melvin J Glimcher, Jerome L AckermanAbstract:Abstract The detailed chemical composition and microstructure of freshly deposited bone mineral, and how these properties change with maturation of the mineral, have been studied intensively and still remain controversial. For example, current analytical technology is inadequate for the unambiguous characterization of the monohydrogen phosphate ions in bone mineral. Using a differential cross polarization/magic angle spinning solid state nuclear magnetic resonance spectroscopy technique, we suppress the dominant orthophosphate (PO 4 -3 ) signal to reveal the spectra of the minor phosphate constituents. This method depends upon differences in the cross polarization time constants for Phosphorus-31 nuclei in protonated and non-protonated phosphate ions. It is now possible for the first time to directly measure both the proportion of acid phosphate (HPO 4 -2 ) as well as the parameters which characterize its isotropic and anisotropic chemical shift. In bone from three species at several developmental stages, we have found a single type of acid phosphate species, identical in all of the specimens examined. The Phosphorus-31 isotropic chemical shift of this acid phosphate group in bone mineral corresponds precisely with that of acid phosphate in octacalcium phosphate, and not with that of brushite. In contrast, the bone acid phosphate anisotropic chemical shift parameters are close to those of brushite, and differ significantly from those of octacalcium phosphate. The orthophosphate resonances of bone mineral, synthetic hydroxyapatite and synthetic octacalcium phosphate share identical chemical isotropic shifts, and similar chemical shift anisotropies. The implication of these results is that the intimate structure of the acid phosphate group in bone mineral is unique, and that none of the common synthetic calcium phosphates accounts well for all of the observed solid state Phosphorus-31 NMR properties of bone mineral.
J Sargentoni - One of the best experts on this subject based on the ideXlab platform.
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in vivo and in vitro hepatic Phosphorus 31 magnetic resonance spectroscopy and electron microscopy in chronic ductopenic rejection of human liver allografts
Gut, 1998Co-Authors: Simon D Taylorrobinson, J Sargentoni, Jimmy D Bell, E L Thomas, C D Marcus, Kumar K Changani, N Saeed, Humphrey Hodgson, B R Davidson, A K BurroughsAbstract:Background —In vivo hepatic Phosphorus-31 magnetic resonance spectroscopy (MRS) provides non-invasive information about phospholipid metabolism. Aims —To delineate MRS abnormalities in patients with chronic ductopenic rejection (CDR) and to characterise spectral changes by in vitro MRS and electron microscopy. Patients and methods —Sixteen liver transplant recipients (four with CDR; 12 with good graft function) and 29 controls (23 healthy volunteers; six patients with biliary duct strictures) were studied with in vivo 31 P MRS. Peak area ratios of phosphomonoesters (PME) and phosphodiesters (PDE), relative to nucleotide triphosphates (NTP) were measured. In vitro MRS and electron microscopy were performed on biopsy specimens from five patients with CDR, freeze clamped at retransplantation. Phosphoethanolamine (PE), phosphocholine (PC), glycerophosphorylethanolamine (GPE), and glycerophosphorylcholine (GPC) concentrations were measured. Results —The 12 patients with good graft function displayed no spectral abnormalities in vivo; the four patients with CDR showed significantly elevated PME:NTP (p Conclusions —The increase in PME:NTP reflects altered phospholipid metabolism in patients with CDR, while the increase in PDE:NTP may represent a significant contribution from bile phospholipid.
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effect of functional grade and etiology on in vivo hepatic Phosphorus 31 magnetic resonance spectroscopy in cirrhosis biochemical basis of spectral appearances
Hepatology, 1995Co-Authors: David K Menon, Simon D Taylorrobinson, J Sargentoni, Jimmy D Bell, I J Cox, D J Bryant, Glyn A Coutts, K Rolles, Andrew K BurroughsAbstract:Hepatic Phosphorus-31 magnetic resonance spectroscopy (31P MRS) was undertaken in 85 patients with histologically proven cirrhosis of varying etiologies and functional severity. Reference data were acquired from 16 healthy volunteers who had no history or evidence of liver disease or alcohol abuse. In vivo hepatic 31P MR spectra were acquired with pulse angle 45 degrees and repetition times (TR) of 5 and 0.5 seconds. Peak area ratios of phosphomonoesters (PME), inorganic phosphate (Pi), and phosphodiesters (PDE) relative to beta ATP, and of PME relative to PDE were calculated from spectra acquired at TR 5 seconds. Estimates of saturation effects for individual resonances were obtained by dividing the peak height at TR 5 seconds by that at TR 0.5 seconds to yield a T1-related signal height ratio (SHR). When compared with reference values, the patients with liver disease showed a significantly higher PME/ATP (P < .0001), PME/PDE (P < .0001), PME SHR (P < .001), and Pi SHR (P < .02), and a lower PDE/ATP (P < .001) and PDE SHR (P < .001). The magnitude of these changes increased significantly and progressively with increasing functional impairment. In patients with compensated cirrhosis spectral appearances varied with etiology; thus, patients with postviral cirrhosis showed a significantly higher Pi/ATP; those with alcoholic cirrhosis, a significantly lower PDE/ATP; and those with cirrhosis secondary to primary sclerosing cholangitis, a significantly lower Pi/ATP than the healthy volunteers or other etiological groups. However, spectral appearances did not vary with etiology in patients with decompensated disease. In vitro 31P MRS of perchloric extracts of samples of liver tissue obtained from 10 patients with cirrhosis at transplant hepatectomy showed increases in levels of the soluble PME metabolites, phosphorylcholine and phosphorylethanolamine, and reductions in the levels of the soluble PDE metabolites, glycerophosphorylcholine and glycerophosphorylethanolamine. These changes suggest regenerative activity in cirrhotic livers. The increases in soluble phosphomonoesters in the aqueous extracts accounted for the increased PME/ATP ratio seen in the in vivo spectra, and might account for the increase in PME SHR. The reduction in soluble phosphodiesters in the aqueous extracts did not entirely account for the reduction PDE/ATP ratio seen in vivo.(ABSTRACT TRUNCATED AT 400 WORDS)
Barbara J Cademenun - One of the best experts on this subject based on the ideXlab platform.
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Phosphorus speciation in riparian soils a Phosphorus 31 nuclear magnetic resonance spectroscopy and enzyme hydrolysis study
Soil Science Society of America Journal, 2013Co-Authors: Eric O Young, Barbara J Cademenun, Donald S Ross, Corey W LiuAbstract:In the Lake Champlain Basin, Phosphorus (P) loading from streambank erosion and cropland are both important P sources, and a better understanding of the factors affecting riparian P loss is needed to help prioritize riparian restoration efforts. We utilized solution Phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy and an enzyme hydrolysis method to characterize P and assess bioavailability in 14 commonly mapped riparian soils from northwestern Vermont. Surface horizons were sampled from distinct series at two riparian restoration sites to capture a range of soil properties. Samples were extracted with sodium hydroxide–ethylenediaminetetra-acetic acid (NaOH-EDTA) and analyzed by solution ³¹P NMR to speciate and quantify P compounds, and commercially available phosphatase enzymes were used to fractionate water-extractable molybdate unreactive P (MUP) into labile orthophosphate monoesters and orthophosphate diesters. Phosphorus extracted by NaOH-EDTA ranged from 74 to 510 mg P kg⁻¹ (representing 14.2 to 31.9% of total soil P), of which 58 ± 13% was identified as organic P. Phosphorus compounds identified in all samples included myo-inositol hexakisphosphate (myo-IHP), scyllo-IHP, neo-IHP, chir-IHP, glycerophosphate, glucose 6-phosphate, mononucleotides, choline phosphate, glucose 1-phosphate, DNA, pyrophosphate, and orthophosphate. Orthophosphate monoesters accounted for 53.7 ± 12.3% of total NaOH-EDTA extractable P and 93 ± 3% of the NaOH-EDTA organic P, indicating the importance of organic P in these soils. Stereoisomers of IHP accounted for 29 ± 7% of NaOH-EDTA extractable Pₒ. For the water extractions, 78 ± 13% of total P was MUP, of which 18 ± 6% was labile orthophosphate monoesters and 31 ± 15% was orthophosphate diesters. Results suggest that analytical indices of riparian P loss potential should consider both organic and inorganic P.
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Phosphorus forms and chemistry in the soil profile under long term conservation tillage a Phosphorus 31 nuclear magnetic resonance study
Journal of Environmental Quality, 2010Co-Authors: Barbara J Cademenun, M R Carter, Dean C JamesAbstract:: In many regions, conservation tillage has replaced conventional tilling practices to reduce soil erosion, improve water conservation, and increase soil organic matter. However, tillage can have marked effects on soil properties, specifically nutrient redistribution or stratification in the soil profile. The objective of this research was to examine soil Phosphorus (P) forms and concentrations in a long-term study comparing conservation tillage (direct drilling, "No Till") and conventional tillage (moldboard plowing to 20 cm depth, "Till") established on a fine sandy loam (Orthic Humo-Ferric Podzol) in Prince Edward Island, Canada. No significant differences in total carbon (C), total nitrogen (N), total P, or total organic P concentrations were detected between the tillage systems at any depth in the 0- to 60-cm depth range analyzed. However, analysis with Phosphorus-31 nuclear magnetic resonance spectroscopy showed differences in P forms in the plow layer. In particular, the concentration of orthophosphate was significantly higher under No Till than Till at 5 to 10 cm, but the reverse was true at 10 to 20 cm. Mehlich 3-extractable P was also significantly higher in No Till at 5 to 10 cm and significantly higher in Till at 20 to 30 cm. This P stratification appears to be caused by a lack of mixing of applied fertilizer in No Till because the same trends were observed for pH and Mehlich 3-extractable Ca (significantly higher in the Till treatment at 20 to 30 cm), reflecting mixing of applied lime. The P saturation ratio was significantly higher under No Till at 0 to 5 cm and exceeded the recommended limits, suggesting that P stratification under No Till had increased the potential for P loss in runoff from these sites.
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Phosphorus 31 nuclear magnetic resonance spectroscopy transect study of poultry operations on the delmarva peninsula
Journal of Environmental Quality, 2009Co-Authors: Jane E Hill, Barbara J CademenunAbstract:Nonpoint source Phosphorus (P) pollution into the Chesapeake Bay watershed from poultry operations contributes to the algal blooms, hypoxia, anoxia, and fish kill events that occur there most years. A major source of soluble, bioavailable P species is poultry litter, which is used as a crop fertilizer on fields adjacent to the tributaries of the Bay. A potentially significant source of orthophosphate in the litter is the heavily phosphorylated compound myo-inositol hexakisphosphate (phytate), which is indigestible by poultry and thus becomes a major component of their excreta. Phytate evaluation in environmental samples is expensive; hence, its impact is not captured in standard farmer-friendly eutrophication potential guides, like Delaware's Phosphorus Site Index. In this transect study of two poultry operations on the Delmarva Peninsula, we measured the incidence of all P compounds using solution 31P nuclear magnetic resonance (NMR) spectroscopy and extracts, relating them to relevant geochemical properties. The contribution of phytate to the overall pool of P declined from around 50% in manures to between 2 and 13% in down-gradient soils and sediments, corresponding to a rise in the relative proportion of orthophosphate (increasing from 39% to 65-88%). The results show that the large pool of phytate P spread onto croplands during standard operating practice at poultry farms on the Delmarva Peninsula does not appear to accumulate; rather, phytate decreases in down-gradient locations, most likely due to transport off-site and/or through in situ biological activity.
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soil and litter Phosphorus 31 nuclear magnetic resonance spectroscopy extractants metals and Phosphorus relaxation times
Journal of Environmental Quality, 2002Co-Authors: Barbara J Cademenun, Corey W Liu, R Nunlist, J G MccollAbstract:Phosphorus-31 nuclear magnetic resonance (NMR) spectroscopy is an excellent tool with which to study soil organic P, allowing quantitative, comparative analysis of P forms. However, for 31P NMR to be tative, all peaks must be completely visible, and in their correct relative proportions. There must be no line broadening, and adequate delay times must be used to avoid saturation of peaks. The objective of this study was to examine the effects of extractants on delay times and peak saturation. Two samples (a forest litter and a mineral soil sample) and three extractants (0.25 M NaOH, NaOH plus Chelex (Bio-Rad Laboratories, Hercules, CA), and NaOH plus EDTA) were used to determine the differences in the concentration of P and cations solubilized by each extractant, and to measure spin-lattice (T1) relaxation times of P peaks in each extract. For both soil and litter, NaOH-Chelex extracted the lowest concentrations of P. For the litter sample, T1 values were short for all extractants due to the high Fe concentration remaining after extraction. For the soil sample, there were noticeable differences among the extractants. The NaOH-Chelex sample had less Fe and Mn remaining in solution after extraction than the other extractants, and the longest delay times used in the study, 6.4 s, were not long enough for quantitative analysis. Delay times of 1.5 to 2 s for the NaOH and NaOH-EDTA were adequate. Line broadening was highest in the NaOH extracts, which had the highest concentration of Fe. On the basis of these results, recommendations for future analyses of soil and litter samples by solution 31P NMR spectroscopy include: careful selection of an extractant; measurement of paramagnetic ions extracted with P; use of appropriate delay times and the minimum number of scans; and measurement of T1 values whenever possible.
A K Burroughs - One of the best experts on this subject based on the ideXlab platform.
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in vivo and in vitro hepatic Phosphorus 31 magnetic resonance spectroscopy and electron microscopy in chronic ductopenic rejection of human liver allografts
Gut, 1998Co-Authors: Simon D Taylorrobinson, J Sargentoni, Jimmy D Bell, E L Thomas, C D Marcus, Kumar K Changani, N Saeed, Humphrey Hodgson, B R Davidson, A K BurroughsAbstract:Background —In vivo hepatic Phosphorus-31 magnetic resonance spectroscopy (MRS) provides non-invasive information about phospholipid metabolism. Aims —To delineate MRS abnormalities in patients with chronic ductopenic rejection (CDR) and to characterise spectral changes by in vitro MRS and electron microscopy. Patients and methods —Sixteen liver transplant recipients (four with CDR; 12 with good graft function) and 29 controls (23 healthy volunteers; six patients with biliary duct strictures) were studied with in vivo 31 P MRS. Peak area ratios of phosphomonoesters (PME) and phosphodiesters (PDE), relative to nucleotide triphosphates (NTP) were measured. In vitro MRS and electron microscopy were performed on biopsy specimens from five patients with CDR, freeze clamped at retransplantation. Phosphoethanolamine (PE), phosphocholine (PC), glycerophosphorylethanolamine (GPE), and glycerophosphorylcholine (GPC) concentrations were measured. Results —The 12 patients with good graft function displayed no spectral abnormalities in vivo; the four patients with CDR showed significantly elevated PME:NTP (p Conclusions —The increase in PME:NTP reflects altered phospholipid metabolism in patients with CDR, while the increase in PDE:NTP may represent a significant contribution from bile phospholipid.