Quantitative differential effects of rhodamine 123 on normal cells and human colon cancer cells by magnetic resonance spectroscopy.

Rhodamine 123 is a lipophilic cationic compound that is selectively taken up by cancer cell mitochondria. This compound is toxic to epithelial cancer cells in vitro and displays significant anticancer activity in vivo. However, the mechanism of action of rhodamine 123 in intact, actively metabolizing cell preparations is unknown.

Creatine kinase-catalyzed reaction rate in the cyanide-poisoned mouse brain.

Brain creatine kinase (CK)-catalyzed phosphorus flux from phosphocreatine (PC) to ATP was measured in vivo in young adult mice made reversibly hypoxic by injection of cyanide. Phosphorus spectra and saturation transfer measurements of CK-catalyzed flux were acquired using a high-field (8.45 T) nuclear magnetic resonance (NMR) spectrometer.

13C- and 31P-NMR studies of human colon cancer in-vitro and in-vivo.

We report comparative 31P-NMR studies in-vivo and in-vitro of the human adenocarcinoma cell line HCT-116 in a high-density, perfused microcarrier culture and as a tumour from the same cell line grown in three different immune-suppressed animal models (NIH triple deficient, Nude, SCID). The phosphate metabolite ratios, pHNMR and intracellular free magnesium, derived from the 31P-NMR spectra, were compared for the in-vivo and in-vitro systems. Results obtained with HCT-116 cells on microcarrier beads are quantitatively similar to that of small (122 mm3), tumours in-vivo derived from the same cell line in any of the immune-suppressed animal systems studied.

Electrode-derived myocardial pH measurements reflect intracellular myocardial metabolism assessed by phosphorus 31-nuclear magnetic resonance spectroscopy during normothermic ischemia.

To determine the ability of extracellular myocardial tissue pH measured with an intramural electrode to reflect myocardial intracellular metabolic status during normothermic ischemia, we studied 14 open-chest dogs with in vivo phosphorus 31-nuclear magnetic resonance spectroscopy during left anterior descending coronary artery occlusion (experimental group, group I, n = 7) or after a sham operation (control group, nonischemic, group II, n = 7). Phosphorus nuclear magnetic resonance spectra were acquired every 5 minutes at 4.7 tesla (256 averages, TR = 1000 msec, pulse width = 30 microseconds) with a 2 cm two-turn radiofrequency surface coil.

Spoiling of transverse magnetization in steady-state sequences.

A detailed analysis is presented of a method to eliminate transverse magnetization prior to each rf excitation in pulse sequences with TR less than T2. It is shown that artifact-free images with high T1 contrast can be obtained only if a phase shift that is incremented during each TR interval is applied to the transverse magnetization. Computer simulations are used to show that when this phase increment is 117 degrees, the steady-state transverse magnetization prior to each rf pulse is nulled over a wide range of T1, T2, and rf tip angles, resulting in optimal T1 contrast.