Influence of Paramagnetic Ions and pH on Proton NMR Relaxation of Biologic Fluids

Barnhart, James L.; Berk, Robert N.

doi:10.1097/00004424-198602000-00009

Cited by 49 publications

(44 citation statements)

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“…Proton relaxation of proteins labeled with paramagnetics depends on the mechanisms of ligand exchange, the symmetry of the ligand field, and the correlation times ( 1 6 ) . Relaxation of large proteins is also dependent on protein size, shape, concentration, and solvent composition (18,19). In an agreement of our results, some earlier results also indicate that, despite a high number of bound gadolinium per protein conjugate, the relaxivity (per Gd concentration) is unchanged (2) or only slightly increased (6,7).…”

Section: Discussionsupporting

confidence: 89%

Proton relaxation enhancement of albumin, immunoglobulin g, and fibrinogen labeled with gd‐dtpa

Paajanen

Reisto

Hemmilä

et al. 1990

Magnetic Resonance in Med

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Bovine serum albumin, immunoglobulin G, and fibrinogen were labeled with Gd-DTPA using a bifunctional chelating agent DTPA anhydride. The protein-(Gd-DTPA) conjugates had 1.4- to 2.0-fold greater longitudinal relaxivities at 0.02 and 0.44 T than the relaxivity of plain Gd-DTPA. The increase of longitudinal relaxivity was not directly related to the size of carrier protein. Up to 50 Gd-DTPA chelates per protein, longitudinal relaxivity of the conjugates was proportional to the concentration of Gd and independent of the Gd/protein ratio.

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Section: Discussionsupporting

confidence: 89%

Proton relaxation enhancement of albumin, immunoglobulin g, and fibrinogen labeled with gd‐dtpa

Paajanen

Reisto

Hemmilä

et al. 1990

Magnetic Resonance in Med

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“…Manganese, iron, copper, and albumin were found to be major components of the total T 1 and T 2 relaxivities (r 1t and r 2t ) of cystic fluid content in odontogenic cysts. Since manganese is the most effective relaxer in various fluids (water, serum, blood, and odontogenic cysts), there is no doubt on the high relaxivity of manganese in hemorrhagic cysts [3,[15][16][17]. However, the relaxivities of iron, copper, albumin, and γ-globulins may change for hemorrhagic cysts since hemorrhagic cysts contain red blood cells.…”

Section: Introductionmentioning

confidence: 99%

Total Relaxivities of Material Content in Various Cysts and Ameloblastoma: Implications for Discriminating Different Fluids

Yilmaz

Güner

Erol

2009

Biol Trace Elem Res

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Nuclear magnetic resonance T(1) and T(2) relaxivities (r(1) and r(2)) exhibit efficiency of a material to alter the relaxation rates (1/T(1) and 1/T(2)), and they are being used for diagnostic purposes. The determination of total relaxivities (r(1t) and r(2t)) of cystic fluid content and ameloblastoma may therefore be useful for discriminative purposes. In order to determine what makes total relaxivities of hemorrhagic cysts, four sets of tubes containing pooled cyst were doped with increasing concentrations of iron, copper, albumin, and gamma-globulins. These sets were replaced in a phantom together with six individual cysts and one ameloblastoma. The relaxation times were measured by magnetic resonance imaging operating at 1.5 T. The relaxivities of individual ions and proteins were determined from the slope of the relation between relaxation rates and concentration, while total relaxivities were determined by using the increases in relaxation rates and material content of cystic fluid (MC). Iron, copper, albumin, and gamma-globulins were found to be the sources of r(1t) and r(2t). Each of r(1t), r(2t), r(1t)MC, r(2t)MC, and r(2t)/r(1t) are distinctive parameters for each cystic category and ameloblastoma. Except for MC, the parameters measured for ameloblastoma are significantly smaller than those of cysts. The similarity of the present results to those used in clinical applications suggests that each of r(1t), r(2t), r(1t)MC, r(2t)MC, and r(2t)/r(1t) has an ability to discriminate various fluids and masses. The present work also suggests that r(1t)MC, r(2t)MC, and r(2t)/r(1t) can be determined in vivo.

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“…The presence of paramagnetic ions in a serum sample, including Fe(III) and Mn(II), is known to increase the NMR spin-lattice relaxation rate (1/7"1) of water protons [1,2]. The magnitude of this increase, the so called paramagnetic contribution (PMC) of the ions to the relaxation rate, is defined as the difference between the observed 1/T I rates of a solution in the presence and the absence of ions [3].…”

Section: Introductionmentioning

confidence: 99%

Paramagnetic contribution of serum iron to the spin-lattice relaxation rate (1/T 1) determined by MRI

1998

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T I maps of phantoms containing the samples of pure serum or Mn(II)-doped serum at pH = 2 were imaged by 1.5 T and 1 T MR Imagers. The /'1 measurements made for the determination of the paramagnetic increase were carried out before and after adding ascorbic acid. The difference of the 1/T~ in samples with and without ascorbic acid was evaluated as the paramagnetic contribution (PMC) of serum iron. As iron content of serum varied from iron deficient to iron overload, the PMC values increased from 0.93 to 0.565 s -~ at 1.5 T and from 0.103 to 0.609 s -~ at 1 T. For confirmative purposes, serum iron of each sample was determined from the paramagnetic contribution and also by an autoanalyzer. The contents of serum iron determined from PMC were in good agreement with those by the autoanalyzer and also with the literature. The data suggest that the paramagnetic contribution of serum iron can be measured by MRI.

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Influence of Paramagnetic Ions and pH on Proton NMR Relaxation of Biologic Fluids

Cited by 49 publications

References 0 publications

Proton relaxation enhancement of albumin, immunoglobulin g, and fibrinogen labeled with gd‐dtpa

Proton relaxation enhancement of albumin, immunoglobulin g, and fibrinogen labeled with gd‐dtpa

Total Relaxivities of Material Content in Various Cysts and Ameloblastoma: Implications for Discriminating Different Fluids

Paramagnetic contribution of serum iron to the spin-lattice relaxation rate (1/T 1) determined by MRI

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