bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectroscopy and imaging with a 4 tesla whole‐body mr system
Authors: Bomsdorf H. , Helzel T. , Kunz D. , Röschmann P. , Tschendel O. , Wieland J. 
Published: March 2007

AbstractMagnetic resonance (MR) spectroscopy and imaging experiments on humans were performed with a whole‐body MR system at a static field of 4 tesla. Spectroscopic studies focussed on 1H, 13C, and 31P. Imaging of humans turned out to be possible, although below the optimum at this field. This holds especially for body imaging, since RF penetration effects and dielectric resonances influence the RF field homogeneity. Excellent volume selective proton spectra of the human cerebrum and cerebellum were obtained using the stimulated echo method. Natural abundance carbon spectra of the human calf were acquired both undecoupled and with narrowband decoupling, resolving the various triglyceride resonances. Broadband decoupling, however, would have violated SAR guidelines. Liver glycogen was detected on natural abundance 13C spectra.
Potential artefacts from overlying tissues in 31p NMR spectra of subcutaneously implanted rat tumours
Authors: Stubbs Marion , Rodrigues Loreta M. , Griffiths John R. 
Published: March 2007

Abstract31P spectra of rat tumours obtained with surface coils are shown to include skin signals of varying intensity. As reported previously by Stubbs, M., Rodrigues L. M., and Griffiths, J. R., (NMR in Biomedicine 1, 50–55, 1988) three hepatomas (rapidly growing Morris heptoma 7777 and slow growing 9618A, and the UA hepatoma) had negligible phosphocreatine (PCr) or creatine (Cr) in acid extracts but frequently had PCr signals in surface coil spectra. Prolactinomas and mammary adenocarcinomas, which had significant PCr and Cr in extracts, showed higher PCr/NTP ratios in spectra taken in vivo than in extracts. A phantom for studying skin signals in vivo is described. A glass sphere of typical tumour size (3–4 mL) is implanted subcutaneously in the rat. Variations in skin signal with pulse duration are demonstrated with this phantom. The factors that could contribute to skin artefact in 31P tumour spectra include: (i) the relative concentrations of metabolites in skin and tumour; (ii) the skin thickness, which depends on the implantation site and rat size; (iii) skin invasion by the tumour; (iv) coil design (solenoid coils and Faraday shields are unlikely to eliminate this problem); (v) pulse repetition times; (vi) pulse duration and other NMR parameters. Careful attention to these factors could reduce skin artefacts.
Characterization of the transport of the nonelectrolyte dimethyl methylphosphonate across the red cell membrane
Authors: Potts Jennifer R. , Kirk Kiaran , Kuchel Philip W. 
Published: March 2007

AbstractWe have refined the method for measuring the equilibrium exchange of the neutral phosphoryl compound dimethyl methylphosphonate across the human red cell membrane using 31P NMR spectroscopy. Using this improved technique we measured a permeability coefficient of dimethyl methylphosphonate of 9.47 ± 1.01 × 10–5cm s–1 at a concentration of 164 mM, at 25 °C. The transport at 25 °C was not saturable up to a concentration of 600 mM and was not inhibited by 4,4′‐diisothiocyano‐2,2′‐disulfonic acid, p‐chloromercuriphenyl sulfonic acid, copper ions or phloretin, or by thiourea or urea at 16 °C. The permeability was enhanced by butanol and phloretin.
31P NMR Study of the Impact of Dietary Manipulation on Tumor Metabolism and Response to Methotrexate
Authors: Sijens P. E. , van Echteld C. J. A. , Neijt J. P. , Schipper J. , Dunki Jacobs P. B. , de Graaf P. W. , Seijkens D. 
Published: March 2007

AbstractThe effects of nutritional manipulation and subsequent chemotherapeutic treatment upon growth and metabolism of a transplanted rat rhabdomyosarcoma were investigated by in vivo 31P NMR spectroscopy. Nutritional manipulation was accomplished by administration of a protein deprived diet containing no protein and 75.5% glucose. After 5 days the protein deprived rats (PD rats) were nutritionally replenished with a normal protein diet containing 27% protein and 47.3% glucose. Twenty‐four hours after nutritional replenishment the PD rats and continuously well‐fed controls (NP rats) received methotrexate (MTX, 30 mg/kg, i.p.). 31P NMR spectroscopy of the tumors 24 h after MTX administration showed a decreased ratio of nucleoside triphosphates to inorganic phosphate (referred to as ‘ATP/P1 ratio’) in PD rats in contrast to an unchanged ATP/P1 ratio in the NP controls. At the time of MTX administration the PD rats had a significantly lower tumor pH than the NP group (6.75 ± 0.03 [SEM] vs 6.95 ± 0.04; p < 0.02). Tumor response in the PD group was significantly (p < 0.01) enhanced compared to the NP group. These findings indicate that a period of dietary protein deprivation combined with a high glucose load and followed by nutritional replenishment impairs tumor metabolism. The altered metabolic status is expressed by acidification of the tumor and distinct changes in ATP/P1 ratio and appears to relate to an enhanced susceptibility to MTX chemotherapy.
31P and 13C NMR Studies of Isolated Perfused Hematopoietic Cells from Leukemic Mice
Authors: Mégnin F. , Nedelec J. F. , Dimicoli J. L. , Lhoste J. M. 
Published: March 2007

AbstractThe myeloproliferative leukemic virus (MPLV) induces within 2–3 weeks a massive infiltration of the adult mouse liver by hematopoietic leukemic cells. Since the metabolism of the infiltrated organ might be correlated with an interaction of two cell populations, it was decided to study the isolated hematopoietic cells separately. The metabolism of these cells embedded in an agarose gel and perfused with labeled substrates was investigated using 31P and 13C NMR. Using [1‐13C]glucose as precursor, sequential 13C NMR spectra showed that the hematopoietic cells were able to store glucose as [1‐13C]glycogen and to metabolize it through the glycolytic pathway to give [3‐13C]lactate as sole end‐product. The liver neoglucogenic substrates: [2‐13C]pyruvate and [3‐13C]alanine are not metabolized by these cells. This suggests that the tricarboxylic acid cycle was not efficient. To investigate further the glycolytic properties of the cells, 10 mM sodium azide was added to the medium containing [1‐13C]glucose. When compared to the aerobic conditions, a 40% decrease of nucleotides (0.10 vs 0.17 m̈mole NTP/109 cells), a degradation of [1‐13C]glycogen and an increase of ca 35% of the glycolytic rate were observed. The analysis of 13C NMR spectra of the perfusates at the end of the perfusion indicates a total conversion of [1‐13C]glucose into [3‐13C]lactate and [3‐13C]pyruvate under anaerobic conditions. These results permit a better understanding of the metabolism of the perfused leukemic livers which are extensively infiltrated by these hematopoietic cells.
The use of in vivo2H NMR spectroscopy to investigate the effects of obesity and diabetes mellitus upon lipid metabolism in mice
Authors: Brereton I. M. , Doddrell D. M. , Oakenfull S. M. , Moss D. , Irving M. G. 
Published: March 2007

AbstractIn vivo deuterium magnetic resonance spectroscopy was used to measure fat utilization rates in diabetic and non‐diabetic obese and non‐obese mice. Monosodium glutamate‐treated mice were used as a model for obesity, and diabetes was induced by administration of streptozotocin. Deuterium levels were enhanced by addition of D2O to drinking water (10% v/v) for a period of 14 days. The deuterium magnetic resonance signals of the body water and adipose tissue were then monitored to measure the rate of deuterium loss from the body. The rates of fat utilization for obese mice were significantly lower (75%, p<0.05) (halflife, t1/2 = 113 ± 13 days) than the rates for non‐obese mice (t1/2 = 30.0 ± 9.0 days). The induction of diabetes caused a large (90%) but proportionally similar increase in fat utilization for both groups of mice (obese, t1/2 = 11.0 ± 5.2; non‐obese, t1/2 = 3.0 ± 0.9). The results suggest that the induction of diabetes in obese mice does not affect the utilization of fat as a metabolic fuel. These preliminary studies indicate that deuterium magnetic resonance spectroscopy may be a useful technique for non‐invasive determination of the rates of fat utilization in vivo.
1H NMR of plasma for detecting cancer. The effect of trauma on linewidths
Authors: Sutherland Garnette , Peeling James 
Published: March 2007

AbstractThe specificity of detecting cancer using the methyl and methylene linewidths in the 1H NMR spectrum of plasma has been examined for patients with brain tumors. Apparently healthy controls are distinguished from patients with metastatic brain tumors or malignant primary intracranial neoplasms, although the amount of overlap with the latter group precludes the use of the method as a diagnostic tool. Furthermore, patients with benign primary intracranial neoplasms are not distinguished from those with malignant primary brain tumors, and non‐tumor neurological patients with traumatic head injury are not distinguished from cancer patients. Surgical treatment of neurological patients results in a significant narrowing of the 1H NMR bands of interest, particularly for patients initially exhibiting broad lines. The narrowing persists for at least 3 weeks. This effect of surgical or other trauma on the 1H NMR linewidths indicates that the method is unsuitable for assessing the efficacy of surgical treatment of cancer.
The 1H NMR visibility of intracellular lactate in Streptococcus faecalis
Authors: Moxon Leith N. , Rogers Peter J. , Brereton Ian M. , Doddrell David M. , Irving Michael G. 
Published: March 2007

Abstract1H NMR studies of glycolysis in washed cell suspensions of Streptococcus faecalis indicated that intracellular lactate is not 1H NMR visible. Evidence for this was gained from time course studies of glycolysis at increasing concentrations of glucose. A close correlation existed between the relative increase in the lactate integral and the enzymatically determined extracellular lactate concentration [Lo]. When ionophores which cause the collapse of the positive intracellular/extracellular lactate gradient were added to cell suspensions following fermentation of 5, 10 and 50 mM glucose, the increase in the lactate integral was proportional to the respective increase in [Lo]. A more direct method for determining the origin of the lactate signal involved centrifugation of a cell suspension after fermentation of 50 mM glucose and measurement of lactate in the extracellular and intracellular fluid. 1H spectra of the cell suspension, supernatant and sonicated pellet revealed that the lactate observed in the cell suspension was equivalent to the lactate in the supernatant alone. The intracellular lactate contained in the pellet represented 42% of the total lactate, indicating that only 58% of lactate is detected by in vivo 1H MRS of S. faecalis. This result is in contrast with the high percentage (70–90%) of in vitro lactate which is detected by in vivo 1H MRS of mammalian brain tissue (Williams S. R. et al. Magn. Res. Med. 7, 425–431, 1988). This may be due to a higher proportion of extracellular lactate in mammalian tissue or differences in the intracellular environments of bacterial and mammalian cells.
1H NMR studies on protein binding of histidine, tyrosine and phenylalanine in blood plasma
Authors: Nicholson Jeremy K. , Gartland Kevin P. R. 
Published: March 2007

AbstractThe binding of histidine (His), phenylalanine (Phe) and tyrosine (Tyr) to macromolecules in blood plasma and serum has been investigated by high resolution 1H NMR spectroscopy. In single pulse and spin‐echo spectra of quality control bovine serum and normal human plasma, there are no resonances in the chemical shift range to high frequency of δ = 5.3 ppm when measured in the pH* (meter reading, uncorrected for the presence of 2H2O) range 3 to 8.5. On acidification of the plasma to pH* < 2.5, resonances from His and Phe are observable. In plasma from patients with Wilson's disease, weak signals from His and Tyr are seen in spin‐echo spectra at pH* 7.6, but increase in strength on acidification and signals from Phe appear at pH* 1.8. Addition of standard solutions containing Tyr, His and especially Phe and Trp to plasma at neutral pH* results in poor recovery of their expected signal intensity in spin‐echo spectra. Addition of 2 M urea to bovine plasma at pH* 4.5 results in the appearance of Phe signals. These data are consistent with Phe and Tyr (and to a lesser extent His) being bound in or to a macromolecular structure at neutral pH from which there is relatively slow exchange with the free solution environment. Experiments with model solutions suggest that serum albumin has a high capacity for binding aromatic amino acids (stabilized by hydrophobic interactions) at neutral pH and this is responsible for the NMR‐invisibility of Tyr and Phe in blood plasma.
31P NMR spectroscopic and near infrared spectrophotometric studies of effects of anesthetics on In vivo RIF‐1 tumors. relationship to tumor radiosensitivity
Authors: Steen R. Grant , Wilson David A. , Bowser Cindy , Wehrle Janna P. , Glickson Jerry D. , Rajan S. Sunder 
Published: March 2007

AbstractMice with subcutaneous RIF‐1 tumors were anesthetized with sodium pentobarbital (PB) or ketamine plus acepromazine (KA) before acquisition of in vivo 31P nuclear magnetic resonance (NMR) spectra from tumors. The area of the inorganic phosphate resonance was significantly greater (relative to phosphomonoesters or the α‐phosphate resonance of nucleoside triphosphate) in spectra obtained under PB anesthesia, suggesting that the hypoxic fraction of the tumor increased following PB anesthesia. In vivo near‐infrared laser spectroscopy directly demonstrated that tumor oxyhemoglobin was reduced by more than 20% following PB but was not significantly affected by KA. Total hemoglobin (tumor blood volume) was reduced by 11% following PB anesthesia, but was not significantly affected by KA. Tumor growth delay induced by γ‐irradiation was shorter when tumors were irradiated under PB anesthesia than when irradiated under KA, showing that PB anesthesia had a radioprotective effect. These studies demonstrate that both the 31P NMR and near infrared methods can detect metabolic or physiological changes associated with an increase in tumor radioresistance (i.e., an increase in the radiobiological hypoxic fraction).
An interesting syndrome of hemolytic anemia, degeneration of the liver and diabetes associated with a high red cell mg‐atpase, detected by 31p NMR spectroscopy
Authors: Kagimoto Tadashi , Higaki Tsuyoshi , Nagata Kohichi , Morino Yoshimasa , Takatsuki Kiyoshi 
Published: March 2007

Abstract31P NMR was used to study the erythrocytes of three patients who exhibited a familial multisystem disease characterized by fatty liver, diabetes and nonspherocytic hemolytic anemia of unknown etiology. 31P NMR measurements disclosed an abnormally high level of intracellular inorganic phosphate (Pi) and an abnormally low level of ATP in the erythrocytes 6 h after blood withdrawal from proband (I–1). This finding suggested that ATP was markedly decreased in the red cells of this proband, as compared with those of normal subjects. Time‐dependent changes of 31P NMR spectra of the erythrocytes from the two daughters (II‐1, II‐2) of the proband demonstrated clearly an enhanced decomposition of ATP with a concomitant increment of Pi. Several ATP‐consuming enzymes in erythrocytes, such as those in the Embden‐Meyerhof system, pentose phosphate pathway enzymes, Na+, K+‐ATPase and Ca2+, Mg2+‐ATPase, were within normal limits of activity, but Mg2+‐ATPase was drastically above the normal limit. The Mg2+‐ATPase activity was 3 times higher in the red cell membranes of these patients than in those from normal subjects.
19F MRS studies of fluoropyrimidine chemotherapy. A review
Authors: McSheehy P. M. J. , Griffiths J. R. 
Published: March 2007

Abstract19F NMR spectroscopy (MRS) has been used to follow the metabolism of the fluoropyrimidine anticancer drug 5‐fluorouracil and its derivatives non‐invasively, both in animals and humans. This review is concerned with the information that has been acquired concerning cytotoxicity and detoxification in relation to studies performed with conventional methods. The potential uses of 19F MRS of fluoropyrimidines in research, particularly concerning combination chemotherapy, and in monitoring therapy, are discussed.
Perturbation of homogeneous magnetic fields by isolated single and confocal spheroids. Implications for NMR spectroscopy of cells
Authors: Kuchel Philip W. , Bulliman Brian T. 
Published: March 2007

AbstractAnalytical expressions for the magnetic potential and the magnetic field strength vector in cells modelled as isolated confocal prolate and oblate spheroids have been derived. The important results which emerged from the analysis are that the magnetic field in the central spheroid, in a series of confocal spheroids, is always uniform; but its magnitude depends upon the orientation of the spheroids relative to the external field. Therefore, the NMR line‐shape derived from an internal solute in a population of sparsely distributed spheroids, with random orientation of the members, is a superposition of Lorentzians; the resulting ‘complicated’ line shape may often appear to be Gaussian. This spectral phenomenon is at least part of the explanation for the non‐Lorentzian character of NMR line‐shapes in the spectra of many biological samples. Quantitative analysis of the NMR line‐shape of an appropriate intracellular solute can in principal yield the orientational distribution of a dilute suspension of cells of uniform size and shape.
Further evidence that the narrow 1H magnetic resonance signals from malignant cells do not arise from intracellular lipid droplets
Authors: Mackinnon Wanda B. , Dyne Marlen , Holmes Kerry T. , Mountford Carolyn E. , Gupta Radhey S. 
Published: March 2007

Abstract1H magnetic resonance (MR) spectroscopy of intact viable malignant cells yields high resolution spectra from lipid. In previous studies we have provided evidence that these signals are generated by neutral lipid located in the plasma membrane in unique domains. We show that intracellular lipid droplets do not contribute to the MR signal. Two malignant Chinese hamster ovary cell lines, EOT and its parental line WT were studied. The EOT cells have a more highly resolved lipid spectrum than the WT, a result which correlates with slightly increased levels of triglyceride in highly purified plasma membranes. The intracellular lipid droplets of both lines were quantified using both fluorescence and electron microscopy but no significant differences were observed. Together these results provide evidence that narrow 1H MR signals from malignant cells arise from neutral lipid in the plasma membrane, rather than from intracellular lipid droplets.
31P NMR spectroscopic study of bioenergetic changes in radiation‐induced fibrosarcoma‐1 after radiation therapy
Authors: Rajan S. Sunder , Wehrle Janna P. , Li Shi‐Jiang , Steen R. Grant , Glickson Jerry D. 
Published: March 2007

AbstractThe effects of localized γ‐irradiation on the in vivo 31P NMR spectra of RIF‐1 tumors grown subcutaneously in C3H/HeN mice have been examined before and during the week after treatment. Increases in the ratio of phosphocreatine (PCr) to inorganic phosphate (Pi) and in tumor pH, and decreases in the ratio of Pi to the b̃ phosphorus resonance of the nucleotide triphosphates (b̃NTP) were observed in irradiated tumors. The time course of changes in the 31P spectrum following treatment was the opposite of the pattern during untreated growth, and the magnitude and duration of the changes increased with increasing radiation dose, decreasing clonogenic cell survival and increasing growth delay. To examine the possibility that nontherapeutic systemic effects of the tumor irradiation were responsible for the changes observed, a number of animals bearing two tumors were examined. One tumor on each mouse was selectively irradiated. Changes in tumor volume, Pi/b̃NTP, PCr/Pi, the ratio of phosphomonoesters to b̃NTP, and tumor pH were all significantly different in the treated compared to the untreated tumor on each animal, indicating that these changes in 31P NMR spectra were a response to radiation therapy and not a systemic response to radiation toxicity.
Characterization of the spleen by In vivo image guided 31P magnetic resonance spectroscopy
Authors: Smith Stephen R. , Martin Peter A. , Davies John M. , Edwards Richard H. T. 
Published: March 2007

AbstractImage localized 31P magnetic resonance spectroscopy of the spleen was performed in six normal volunteers, 13 patients with splenomegaly due to haematological malignancies, and two patients with benign causes of splenomegaly. The malignant disorders had elevated phosphomonoesters (PME) compared to controls, probably due to increased turnover of membrane phospholipids, with variable alterations in high energy phosphates. There appeared to be no relationship between grade of malignancy and relative PME peak area. An overlap in spectral characteristics between the benign and malignant cases of splenomegaly existed. Serial studies in a patient with high grade lymphoma receiving combination chemotherapy showed changes in phosphorus spectra, with an increase in the phosphodiester/b̃adenosine triphosphate ratio.
Simultaneous multivolume spectroscopy (simuvosp) using local techniques
Authors: Müller S. , Hafner H.‐P. , Beckmann N. 
Published: March 2007

AbstractMR spectra simultaneously acquired from different locations in the human body may be obtained with the SIMUVOSP technique (Simultaneous Multivolume Spectroscopy). SIMUVOSP is based on multifrequency selective RF pulses which encode positional information of the spins into the phase of the MR signal. This paper describes SIMUVOSP strategies for 1H, 31P and 13C spectroscopy.For 1H SIMUVOSP the STEAM experiment may be modified by replacing the selective RF pulses with SIMUFREX pulses (Simultaneous Multifrequency Excitation pulses). This modification allows the simultaneous spectroscopic examination of different regions in the human brain. For 31P SIMUVOSP the ISIS method is combined with SIMUFRIN (Simultaneous Multifrequency Inversion) pulses, which generate the inversion of multiple regions during the RF pulse. An application of 31P SIMUVOSP is the study of the metabolic heterogeneity of the high energy phosphates within the human body. For 13C spectroscopy a localized polarization transfer experiment is combined with multivolume excitation. In this way SIMUVOSP on protons is extended to 13C multivolume spectroscopy.
The importance of the voxel size in clinical 1H spectroscopy of the human brain
Authors: Ernst Th. , Hennig J. , Ott D. , Friedburg H. 
Published: March 2007

AbstractIt is demonstrated that it is possible to acquire two volume selective 1H NMR spectra of human brain in vivo, consisting of voxels of 1.5 × 1.5 × 1.5 cm3, within 14 min with a good S/N ratio. This is mainly achieved by the application of a PRESS sequence generating a spin‐echo of the VOI at 135 ms in conjunction with the STABLE technique by which two spectra can be recorded in an interlaced mode. The Bo homogeneity over such small voxels is considerably higher than over larger voxels. With these methodological improvements it is possible to observe morphological heterogeneity of tumors. The results indicate that spectral changes seem to correlate with the metabolic state of the tumor rather than the tumor type. Additionally the spectrum of a patient with multiple sclerosis suggests that even differentiation between tumors and other lesions might not be possible.
Lactate distribution in ischemic rat kidney by 4D spectroscopic imaging
Authors: Lazeyras Francois , Aue Walter P. 
Published: March 2007

AbstractA lactate map of the rat kidney is presented, using a four‐dimensional spectroscopic imaging technique in connection with a double resonance editing scheme. A voxel size of 12 μL has been obtained, and we show that eddy currents do not affect the line shape of an individual voxel.