High-resolution Magnetic Resonance Spectroscopy Research Articles

Does a passive transport between modified plasma lipoproteins and cell membranes exist in cancer disease?

Malignant diseases increase the level of total lipids in blood and modify their distribution in lipoprotein carriers affecting lipid exchanges between serum and tissues. These exchanges take place by active and/or passive ways which coexist in most tissues. This work concerns the exploration of passive diffusion, using the red blood cell mechanism as a model. Lipid components of normal and cancerous rat erythrocytes have been investigated by Proton and Carbon high resolution Magnetic Resonance Spectroscopy (H-1 and C-13 MRS). As previously established, MRS yields the usual molar ratio cholesterol/phospholipids and moreover provides information on the length and degree of unsaturation of the phospholipid fatty acyl chains. No modification has been recorded in erythrocyte lipids between cancer and control populations. These data would suggest that erythrocytes can maintain membrane lipid homeostastis during malignancy. The numerous abnormalities noted in their membrane fuction remain to be explained.

29Si-NMR study of hydrolysis and initial polycondensation processes of organoalkoxysilanes. II. Methyltriethoxysilane

The hydrolysis and initial polycondensation processes of methyltriethoxysilane (MTES) have been investigated by high-resolution 29Si-nuclear magnetic resonance spectroscopy ( 29Si-NMR). MTES was hydrolyzed in the system with MTES:ethyl alcohol:water:HCL = 1:4: x: y; x = 1, 2, 3, 6; y = 1 × 10 −4, 1 × 10 −2. Signals due to end and middle groups of polysiloxanes formed sub-regions on the basis of the number of hydroxyl groups attached to silicon, and the sub-region for silicon possessing more hydroxyl groups was observed at a lower field. Based on signal intensities, the signals due to the dimers (Me(HO) 2SiOSi(OH) 2Me and Me(HO) 2SiOSi(OH)OEt)Me) and the trimer (Me(HO) 2SiOSiMe(HO)OSi(OH) 2Me) (MeCH 3, EtC 2H 5) were identified.

Proton MR and human cervical neoplasia: ex vivo spectroscopy allows distinction of invasive carcinoma of the cervix from carcinoma in situ and other preinvasive lesions.

The concept that high-resolution (8.5-T) hydrogen-1 magnetic resonance (MR) spectroscopy can be used as an adjunct to conventional histologic diagnosis of cervical neoplasia was investigated. Cervical biopsy specimens (n = 159) were examined with H-1 MR spectroscopy and the results compared with results of histopathologic analysis. A high-resolution lipid MR spectrum was observed in 39 of 40 invasive carcinomas, whereas the 119 preinvasive samples showed little or no lipid spectrum but were characterized by a strong unresolved resonance between 3.8 and 4.2 ppm. Peak ratios of the methylene/methyl and the unresolved/methylene resonances allowed accurate distinction between invasive and preinvasive epithelial malignancy (P < .0001). Since MR spectroscopic examination does not destroy the specimen, the specimens remained intact for further testing and histopathologic analysis. The authors conclude that H-1 MR spectroscopy can independently allow distinction between invasive and preinvasive lesions of the cervix and has the potential to assist in clinical management of cervical cancer.

1H magnetic resonance spectroscopy of extracts of human epileptic neocortex and hippocampus.

We used high-resolution 1H magnetic resonance spectroscopy to determine the concentrations of several metabolites (lactate, alanine, N-acetylaspartate [NAA], gamma-aminobutyrate, glutamate, aspartate, creatine, cholines, taurine, inositol, and succinate) in tissue from patients undergoing surgical treatment of intractable epilepsy, and correlated the metabolite profiles with the results of histopathologic analysis of the excised tissue. We found no differences in metabolite levels for tissue from actively spiking or nonspiking neocortical sites in temporal lobe epilepsy patients. In neocortical tissue from patients with chronic localized encephalitis (Rasmussen's encephalitis), the metabolite concentrations varied with the severity and extent of the encephalitis. In tissue showing mild encephalitis and mild histologic abnormalities, the metabolite levels differed little from those found for nonencephalitic neocortical tissue. Tissue showing marked abnormalities and extensive encephalitis had decreased NAA, glutamate, cholines, and inositol. In hippocampal tissue from temporal lobe epilepsy patients, the levels of NAA, glutamate, and aspartate were lower and the levels of alanine, taurine, and inositol were higher than in neocortical tissue from the same patients. The decrease in the levels of NAA and glutamate was greater in gliotic hippocampal tissue. The results suggest that in vivo 1H magnetic resonance spectroscopy may aid in diagnosing the extent of chronic localized encephalitis and the severity of hippocampal gliosis.

Phosphocreatine hydrolysis by 31P-NMR at the onset of constant-load exercise in humans.

The kinetics of phosphocreatine (PC) breakdown in human plantar flexors at the onset of constant-load aerobic exercise was determined by high-resolution 31P-nuclear magnetic resonance spectroscopy (NMRS). The half time of the process (t1/2PC) was obtained by fitting curves (n = 13) from five subjects at various aerobic work loads for which muscle pH was not different from that at rest. Steady-state PC concentration ([PC]) was not < 70% of the resting value and was linearly related to the work load (w) ([PC] = -3.01 +/- 0.08 w + 1 (r = 0.48, 2P < 0.1)). The average t1/2PC was 16.2 s and was independent of work load. Because the half time of the muscle PC kinetics reflects the half time of the O2 uptake (MO2) kinetics (t1/2MO2), the latter is equal to that found earlier in the isolated perfused dog gastrocnemius. Whereas in the dog the above t1/2MO2 compares well with the homologous half time of the O2 uptake at the alveolar level, in humans such equivalence is found only at extremely low work loads, when the transient contribution by anaerobic glycolysis is negligible.

Quantitative analysis of rat synaptosomes and cerebrum using high-resolution 1H magnetic resonance spectroscopy

This study explored the utility of 1H magnetic resonance spectroscopy to study a standard synaptosomally enriched preparation (P2 pellet) made from rat cerebrum. The preparation contained high concentrations of N-acetylaspartate and γ-aminobutyric acid and low concentrations of glutamine, indicating that they were in fact rich in neuronal cytosol. Synaptosomes contained half the lactate and glutamine of cerebrum. Alanine, aspartate, glutamate, and succinate had the same concentrations in synaptosomes and cerebrum.

29Si-NMR study of hydrolysis and initial polycondensation processes of organoalkoxysilanes. I. Dimethyldiethoxysilane

Abstract The hydrolysis and initial polycondensation processes of methyltriethoxysilane (MTES) have been investigated by high-resolution 29Si-nuclear magnetic resonance spectroscopy (29Si-NMR). MTES was hydrolyzed in the system with MTES:ethyl alcohol:water:HCL = 1:4:x:y; x = 1, 2, 3, 6; y = 1 × 10−4, 1 × 10−2. Signals due to end and middle groups of polysiloxanes formed sub-regions on the basis of the number of hydroxyl groups attached to silicon, and the sub-region for silicon possessing more hydroxyl groups was observed at a lower field. Based on signal intensities, the signals due to the dimers (Me(HO)2SiOSi(OH)2Me and Me(HO)2SiOSi(OH)OEt)Me) and the trimer (Me(HO)2SiOSiMe(HO)OSi(OH)2Me) (MeCH3, EtC2H5) were identified.

Hepatic D‐galactosamine toxicity studied with localized in Vivo31P magnetic resonance spectroscopy in intact rats

Spatially resolved 31P magnetic resonance spectroscopy (MRS) at 4.7 T was applied to noninvasively assess liver phosphorus metabolites in a biochemically well-characterized model of hepatotoxicity induced by injection of a sublethal dose of D-galactosamine (galN). A newly developed hybrid method based on spectral localization with B0 and B1 gradients was employed to obtain multivoxel spectra in intact anesthesized rats. Spatially localized in vivo spectra were recorded 0 to 26 h after galN injection of female rats. In response to galN exposure, diphosphodiester peaks ascribed to UDP-hexosamines became detectable by 4 h and persisted up to 26 h. A metabolite coresonating with inorganic phosphate increased rapidly in intensity by 2 h after galN and returned to baseline by 18 h; this resonance was shown not to be Pi and was assigned to galN-1-phosphate by subsequent high resolution MRS experiments on extracts prepared from these livers. These results confirmed in vivo the metabolic perturbations described previously for this model of hepatotoxicity following biochemical studies based on classical extraction methods. Unlike the in vitro studies, however, these noninvasive experiments provided additional information on the time course of metabolic alterations on the same animal.

Characterization of Prostate Cancer, Benign Prostatic Hyperplasia and Normal Prostates Using Transrectal 31Phosphorus Magnetic Resonance Spectroscopy: A Preliminary Report

We assessed the ability of 31phosphorus (31P) transrectal magnetic resonance spectroscopy to characterize normal human prostates as well as prostates with benign and malignant neoplasms. With a transrectal probe that we devised for surface coil spectroscopy we studied 15 individuals with normal (5), benign hyperplastic (4) and malignant (6) prostates. Digital rectal examination, transrectal ultrasonography and magnetic resonance imaging were used to aid in accurate positioning of the transrectal probe against the region of interest within the prostate. The major findings of the in vivo studies were that normal prostates had phosphocreatine-to-adenosine triphosphate (ATP) ratios of 1.2 ± 0.2, phosphomonoester-to-β-ATP ratios of 1.1 ± 0.1 and phosphomonoester-to-phosphocreatine ratios of 0.9 ± 0.1. Malignant prostates had phosphocreatine-to-β-ATP ratios that were lower (0.7 ± 0.1) than those of normal prostates (p <0.02) or prostates with benign hyperplasia (1.1 ± 0.2, p <0.01). Malignant prostates had phosphomonoester-to-β-ATP ratios (1.8 ± 0.2) that were higher than that of normal prostates (p <0.02). Using the phosphomonoester-to-phosphocreatine ratio, it was possible to differentiate metabolically malignant (2.7 ± 0.3) from normal prostates (p <0.001), with no overlap of individual ratios. The mean phosphomonoester-to-phosphocreatine ratio (1.5 ± 0.5) of prostates with benign hyperplasia was midway between the normal and malignant ratios, and there was overlap between individual phosphomonoester-to-phosphocreatine ratios of benign prostatic hyperplasia glands with that of normal and malignant glands. To verify the in vivo results, we performed high resolution magnetic resonance spectroscopy on perchloric acid extracts of benign prostatic hyperplasia tissue obtained at operation and on a human prostatic cancer cell line DU145. The extract results confirmed the differences in metabolite ratios observed in vivo. We conclude that transrectal 31P magnetic resonance spectroscopy can characterize metabolic differences between the normal and malignant prostate.

Hydration—dehydration-induced conformational changes of agarose, and kappa- and iota-carrageenans as studied by high-resolution solid-state 13C-nuclear magnetic resonance spectroscopy

High-resolution, solid-state 13C-n.m.r. spectra of agarose, and kappa- and iota-carrageenans were recorded for various states, including anhydrous and hydrated powder, film, gel, and lyophilized gel. The 13C-n.m.r. spectra varied substantially with the extent of hydration. Fully hydrated samples, as in the agarose gels, gave rise to 13C-n.m.r. peaks of the narrowest line widths, whereas dehydration caused considerable line-broadening or displacement of the G1 peak (or both). These observations were interpreted in terms of hydration-dehydration-induced conformational alteration or readjustment, depending on the extent of hydration or dehydration and the variety of samples used. 13C-n.m.r. spectrometry of agarose gel by solid-state n.m.r. technique also indicated the existence of a rather rigid network structure with an anisotropic molecular tumbling.

Classification of human tumours by high-resolution magnetic resonance spectroscopy : Mountford CE; May GL; Williams PG; et al. Ludwig Institute for Cancer Research (Sydney Branch), Camperdown, NSW, Australia Lancet; 1/8482 (651–653) 1986

International Journal of Gynecology & ObstetricsVolume 25, Issue 2 p. 169-169 Citations from the literature oncology Classification of human tumours by high-resolution magnetic resonance spectroscopy Mountford CE; May GL; Williams PG; et al. Ludwig Institute for Cancer Research (Sydney Branch), Camperdown, NSW, Australia Lancet; 1/8482 (651–653) 1986 First published: April 1987 https://doi.org/10.1016/0020-7292(87)90013-0AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume25, Issue2April 1987Pages 169-169 RelatedInformation

Rotational spectroscopy of DO2 by FIR LMR and millimeter-wave absorption

Abstract We report the measurement of approximately 50 rotational transitions in the DO 2 radical between 230 and 2530 GHz by high-resolution millimeter-wave and far-infrared laser magnetic resonance spectroscopy. The radical was generated in the gas phase by the reaction of chlorine atoms and oxygen or discharged oxygen with deuterated methanol. The data were analyzed in conjunction with previously published high-resolution spectra of the molecule in the ground vibronic state in order to extract the best set of parameters in the effective Hamiltonian describing the molecule. The fine structure (spin-rotation) parameters derived in the present work were used together with those for HO 2 [A. Charo and F. C. De Lucia, J. Mol. Spectrosc. 94, 426–436 (1982)] in order to determine all of the symmetry-allowed spin-rotation tensor components for the hydroperoxyl radical. The results cannot be interpreted in terms of contamination of the ground state wavefunction by the lowest lying A 2 A state alone and information from quantum chemical calculations of spin-orbit matrix elements between the ground and higher excited states or additional experimental data involving higher excited electronic states are necessary before a complete rationalization of the results is possible.

Magnetic resonance imaging of the cardiovascular system

Magnetic resonance imaging (MRI) is a completely noninvasive technique for the visualization of the cardiovascular system.1-3 It employs high-strength static magnetic fields, low-strength changing magnetic fields, and radiofrequency pulses to generate tomographic images of the body with high soft tissue contrast.*r5 Because of the abundance of hydrogen in biologic tissues and its efficiency (maximum number of nuclei per atomic number) for magnetic resonance, hydrogen (proton) resonance has been used for imaging. On the other hand, the nondestructive in vivo monitoring of metabolism by the magnetic resonance process requires the study of elements of biologic interest other than hydrogen. Because of the lesser abundance and lower efficiency of nonhydrogen species such as carbon 13 and phosphorus 31, imaging with these elements is much more difficult than hydrogen magnetic resonance imaging.6 The distribution of these elements in metabolically important compounds can be investigated by high resolution magnetic resonance spectroscopy rather than by imaging. Even at this early juncture in the development of MRI for biologic studies, it seems likely that both hydrogen imaging and in vivo spectroscopy of a variety of elements will have enormous importance for clinical diagnosis and scientific inquiry in the cardiovascular system. This report will review the early work on MRI of the cardiovascular system conducted over the past few years in our own and in several other MRI laboratories. Since MRI is such a new cardiovascular imaging modality, a brief review of closely relevant physical principles and instrumentation is warranted at the outset.

High-resolution laser magnetic resonance and infrared-radiofrequency double-resonance spectroscopy of NO and its isotopes near 5.4 μm

The fundamental band of NO has been investigated by the laser magnetic resonance method, in which the absorption lines from an NO sample located inside the laser cavity were Zeeman tuned into resonance with fixed CO laser transitions. Saturation dips with a width of <2 MHz were observed, allowing the resolution of hyperfine and Λ-doubling structure in the NO spectrum. Transitions due to the weak 2-1 “hot” band and the 2 Π 1 2 ← 2 Π 1 2 satellite band of 14N 16O were observed, as were transitions due to the 15N 16O, 14N 18O, and 14N 17O isotopic species in natural abundance. Data from the present work were combined with previous measurements to obtain a consistent set of vibration-rotation parameters for five isotopic species of NO. An infrared-radiofrequency double-resonance spectrum was observed which allowed the precise (∼20 kHz) measurement of some hyperfine Λ-doubling transitions within the v = 1 state of 14N 16O.

ChemInform Abstract: MODEL STUDIES OF PYRIDOXAL SCHIFF′S BASES. COPLANARITY AND INTRAMOLECULAR HYDROGEN BONDING

The interactions between the pi cloud of the aromatic ring and the pi-electron pair of the imine double bond of aromatic oximes as model compounds of pyridoxal Schiff's bases have been studied by high-resolution carbon-13 magnetic resonance spectroscopy. The coplanarity and intramolecular hydrogen bonding have been determined by 13C-1H long range couplings. This detailed investigation of 13C-1H coupling also provides unambiguous proof of the existence of the enol-imine tautomers in chloroform and dimethyl sulfoxide solutions. The tautomerism between the enol-imine and keto-enamine is discussed.

Model studies of pyridoxal Schiff's bases. Coplanarity and intramolecular hydrogen bonding.

The interactions between the pi cloud of the aromatic ring and the pi-electron pair of the imine double bond of aromatic oximes as model compounds of pyridoxal Schiff's bases have been studied by high-resolution carbon-13 magnetic resonance spectroscopy. The coplanarity and intramolecular hydrogen bonding have been determined by 13C-1H long range couplings. This detailed investigation of 13C-1H coupling also provides unambiguous proof of the existence of the "enol-imine" tautomers in chloroform and dimethyl sulfoxide solutions. The tautomerism between the "enol-imine" and "keto-enamine" is discussed.