Determination of water compartments in rat myocardium using combined D-T1 and T1-T2 experiments.

We have used combined D-T1 and T1-T2 correlation experiments to explore water compartments in rat heart tissue (myocardium). The results show that two main compartments can be identified, which we assign to extracellular (ec) and intracellular (ic) water. The exchange rate of water across the cell membrane was found to be on the order of 0.

Manganese-calcium interactions with contrast media for cardiac magnetic resonance imaging: a study of manganese chloride supplemented with calcium gluconate in isolated Guinea pig hearts.

Objectives: Manganese ions (Mn) enter cardiomyocytes via calcium (Ca) channels and enhance relaxation intracellularly. To prevent negative inotropy, new Mn-releasing contrast agents have been supplemented with high Ca. The study aim was to investigate how this affects cardiac function and magnetic resonance efficacy.

Correlations between diffusion, internal magnetic field gradients, and transverse relaxation in porous systems containing oil and water.

The main focus in this study is to investigate the correlations between internal magnetic field gradients (G0) and transverse relaxation times in liquid-saturated packings of glass beads of different wettabilities. We show how these correlations can be expressed as two-dimensional (2D) diagrams of distribution functions between internal magnetic field gradients and T2 values. In the case where it is difficult to distinguish the signals from oil and water, we separate them based on their difference in diffusivity.

Intracellular manganese ions provide strong T1 relaxation in rat myocardium.

The efficacy of manganese ions (Mn2+) as intracellular (ic) contrast agents was assessed in rat myocardium. T1 and T2 and Mn content were measured in ventricular tissue excised from isolated perfused hearts in which a 5-min wash-in with 0, 30, 100, 300, or 1000 microM of Mn dipyridoxyl diphosphate (MnDPDP) was followed by a 15-min wash-out to remove extracellular (ec) Mn2+. An inversion recovery (IR) analysis at 20 MHz revealed two T1 components: an ic and short T1-1 (650-251 ms), and an ec and longer T1-2 (2712-1042 ms).

Manganese ions as intracellular contrast agents: proton relaxation and calcium interactions in rat myocardium.

Paramagnetic manganese (Mn) ions (Mn(2+)) are taken up into cardiomyocytes where they are retained for hours. Mn content and relaxation parameters, T(1) and T(2), were measured in right plus left ventricular myocardium excised from isolated perfused rat hearts. In the experiments 5 min wash-in of MnCl(2) were followed by 15 min wash-out to remove extracellular (ec) Mn(2+) MnCl(2), 25 and 100 micro M, elevated tissue Mn content to six and 12 times the level of control (0 micro M MnCl(2)).

A putative DNA-binding domain in the NUCKS protein.

We have studied the DNA-binding properties of a NUCKS-derived, synthetic peptide containing an extended GRP motif. This peptide binds to random-sequence DNA, but did not bind preferentially to poly(dA-dT). A synthetic peptide with the same amino acid composition but with a random sequence did not bind to DNA, suggesting that the structure of the DNA-binding domain plays a pivotal role in the interaction with DNA.