The effects of proteins on the proton N.M.R. transverse relaxation time of water

Hills, B.P.; Takács, S.; Belton, Peter

doi:10.1080/00268978900101541

Cited by 112 publications

(81 citation statements)

References 22 publications

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“…In the presence of aggregation or gelation processes another relaxation pathway can also be important, such as contributions from the exchange of water protons between the bulk and bound water phases by chemical exchange and/or molecular diffusion [30][31][32][33][34][35][36]. Unfortunately, it is difficult to distinguish exactly the contributions of these various relaxation mechanisms.…”

Section: Resultsmentioning

confidence: 99%

“…Many authors have shown that in dilute aqueous carbohydrate systems enhancement of the spin-spin relaxation mainly depends on the rapid proton exchange mechanism between water and carbohydrate hydroxyl groups [30,31,34]. In the presence of aggregation or gelation processes another relaxation pathway can also be important, such as contributions from the exchange of water protons between the bulk and bound water phases by chemical exchange and/or molecular diffusion [30][31][32][33][34][35][36].…”

Section: Resultsmentioning

confidence: 99%

“…NMR proton spin-spin relaxation time measurements have been found useful for monitoring the mobility and state of aggregation of biomolecules (proteins and polysaccharides) in solution and gelled systems [15,[30][31][32][33][34][35][36][37][38]. Therefore, in this paper we used 1 H NMRD method in combination with spin-spin relaxation measurements to study calcium induced gelation of LM pectin solution in the absence of the buffering salt (only in water medium).…”

Section: Introductionmentioning

confidence: 99%

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¹H NMR and Rheological Studies of the Calcium Induced Gelation Process in Aqueous Low Methoxyl Pectin Solutions

2005

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The 1 H NMR relaxometry in combination with water proton spin-spin relaxation time measurements and rheometry have been applied to study the ionic gelation of 1% w/w aqueous low methoxyl pectin solution induced by divalent Ca 2+ cations from a calcium chloride solution. The model-free approach to the analysis of 1 H NMR relaxometry data has been used to separate the information on the static (β) and dynamic ( τc ) behaviour of the systems tested. The 1 H NMR results confirm that the average mobility of both water and the pectin molecules is largely dependent on the concentration of the cross-linking agent. The character of this dependency (β, τ c and T2 vs. CaCl2 concentration) is consistent with the two-stage gelation process of low methoxyl pectin, in which the formation of strongly linked dimer associations (in the range of 0-2.5 mM CaCl 2 ) is followed by the appearance of weak inter-dimer aggregations (for CaCl2 ≥ 3.5 mM). The presence of the weak gel structure for the sample with 3.5 mM CaCl 2 has been confirmed by rheological measurements. Apart from that, the T1 and T2 relaxation times have been found to be highly sensitive to the syneresis phenomenon, which can be useful to monitor the low methoxyl pectin gel network stability.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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¹H NMR and Rheological Studies of the Calcium Induced Gelation Process in Aqueous Low Methoxyl Pectin Solutions

2005

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“…It has been shown that, in biological tissues, diffusion (rotational and translational) contributions to all relaxation rates are constant and independent of frequency (200).…”

Section: Mechanism Of T 1r Relaxation In Cartilagementioning

confidence: 99%

Sodium and T_1ρ MRI for molecular and diagnostic imaging of articular cartilage

et al. 2006

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In this article, both sodium magnetic resonance (MR) and T 1r relaxation mapping aimed at measuring molecular changes in cartilage for the diagnostic imaging of osteoarthritis are reviewed. First, an introduction to structure of cartilage, its degeneration in osteoarthritis (OA) and an outline of diagnostic imaging methods in quantifying molecular changes and early diagnostic aspects of cartilage degeneration are described. The sodium MRI section begins with a brief overview of the theory of sodium NMR of biological tissues and is followed by a section on multiple quantum filters that can be used to quantify both bi-exponential relaxation and residual quadrupolar interaction. Specifically, (i) the rationale behind the use of sodium MRI in quantifying proteoglycan (PG) changes, (ii) validation studies using biochemical assays, (iii) studies on human OA specimens, (iv) results on animal models and (v) clinical imaging protocols are reviewed. Results demonstrating the feasibility of quantifying PG in OA patients and comparison with that in healthy subjects are also presented. The section concludes with the discussion of advantages and potential issues with sodium MRI and the impact of new technological advancements (e.g. ultra-high field scanners and parallel imaging methods). In the theory section on T 1r , a brief description of (i) principles of measuring T 1r relaxation, (ii) pulse sequences for computing T 1r relaxation maps, (iii) issues regarding radio frequency power deposition, (iv) mechanisms that contribute to T 1r in biological tissues and (v) effects of exchange and dipolar interaction on T 1r dispersion are discussed. Correlation of T 1r relaxation rate with macromolecular content and biomechanical properties in cartilage specimens subjected to trypsin and cytokineinduced glycosaminoglycan depletion and validation against biochemical assay and histopathology are presented. Experimental T 1r data from osteoarthritic specimens, animal models, healthy human subjects and as well from osteoarthritic patients are provided. The current status of T 1r relaxation mapping of cartilage and future directions is also discussed. Copyright # 2006 John Wiley & Sons, Ltd. KEYWORDS: cartilage; arthritis; spin-lock; T1rho; sodium; MRI OSTEOARTHRITIS Osteoarthritis (OA) affects more than half of the population above the age of 65 (1,2) and has a significant negative impact on the quality of life of elderly individuals (3). The economic costs in the USA from OA have been estimated to be more than 1% of the gross domestic product (4). OA is now increasingly viewed as a metabolically active joint disorder of diverse etiologies. The biochemistry of the disease is characterized by the following changes in cartilage: reduced proteoglycan (PG) concentration, possible changes in the size of collagen fibril and aggregation of PG, increased water content and increased rate of synthesis and degradation of matrix macromolecules. The earliest changes in the cartilage due to OA result in a partial breakdown in the proteoglyc...

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“…The main controversy concerns the relative importance of three mechanisms 1) the nature of the proteinassociated water that contributes to the relaxation, 2) the contribution of the biopolymer protons exchanging with the water, and 3) the effects of the cross-relaxation between spinlattice relaxation associated with water protons and biopolymer protons [27]. Using NMR CPMG T 2 dispersion [28][29][30][31] and quantitative analysis of the T 1 magnetic relaxation dispersion (MRD) [27,[32][33][34][35][36], it is now clear that the water relaxation can be explained by taking into account only two relaxation mechanisms, the protein-exchanging protons relaxation and the relaxation from the internal water molecule. Moreover, analysis of 1 H, 2 H and 17 O MRD has demonstrated that the internal molecules involved in this mechanism are only marginally less mobile than the bulk water and should not be considered as "bound", as they were for many years [33], and the number of water molecules is very small.…”

Section: Water Relaxation: a Multiscale Probe Of Food Structurementioning

confidence: 99%

Investigations of food colloids by NMR and MRI

Mariette¹

2009

Current Opinion in Colloid & Interface Science

118

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Since the publication of the ISO method for measurement of solid fat content using NMR relaxation at low field, the application of this technique to the characterisation of food composition and food structure on several length scales has expanded considerably.Improvements in the electronic and computational specifications of NMR spectrometers and the use of more sophisticated signal processing methods have led to several new applications, and NMR, previously recognized as a powerful technique to provide information regarding composition, is now widely used for microstructural investigations. Moreover, MRI applications have in recent years been extended from the medical field to food science and this has opened up new opportunities for the understanding of food. We examine here recent developments in these techniques, including NMR relaxation, multidimensional NMR relaxation, diffusion NMR and MRI.

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The effects of proteins on the proton N.M.R. transverse relaxation time of water

Cited by 112 publications

References 22 publications

¹H NMR and Rheological Studies of the Calcium Induced Gelation Process in Aqueous Low Methoxyl Pectin Solutions

¹H NMR and Rheological Studies of the Calcium Induced Gelation Process in Aqueous Low Methoxyl Pectin Solutions

Sodium and T_1ρ MRI for molecular and diagnostic imaging of articular cartilage

Investigations of food colloids by NMR and MRI

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The effects of proteins on the proton N.M.R. transverse relaxation time of water

Cited by 112 publications

References 22 publications

1H NMR and Rheological Studies of the Calcium Induced Gelation Process in Aqueous Low Methoxyl Pectin Solutions

1H NMR and Rheological Studies of the Calcium Induced Gelation Process in Aqueous Low Methoxyl Pectin Solutions

Sodium and T1ρ MRI for molecular and diagnostic imaging of articular cartilage

Investigations of food colloids by NMR and MRI

Contact Info

Product

Resources

About

¹H NMR and Rheological Studies of the Calcium Induced Gelation Process in Aqueous Low Methoxyl Pectin Solutions

¹H NMR and Rheological Studies of the Calcium Induced Gelation Process in Aqueous Low Methoxyl Pectin Solutions

Sodium and T_1ρ MRI for molecular and diagnostic imaging of articular cartilage