A. L. Hopkins

Nuclear Magnetic Resonance Studies of Living Muscle

Measurements of nuclear magnetic relaxation times for protons of water in living skeletal frog muscle show the transverse relaxation time, T2, increases when a muscle contracts isometrically. This result and other experimental data suggest that a fraction of the intracellular water molecules have restricted rotational freedom and that this fraction decreases when contraction occurs.

Dimethyl Sulfoxide and Related Compounds. Some Effects on Human Fibroblasts in vitro.

Summary Human fibroblast cultures grown in 1% DMSO have demonstrated a lag in generation time, but an increase in total hydroxyproline concentration when compared with control cultures. An inverse relationship between growth rate and hydroxyproline concentration for each culture was noted. Somewhat similar findings were obtained in cultures treated with acetone and methanol.

Oxygen-17 contrast agents. Fast imaging techniques.

Hopkins AL, Haacke EM, Barr RG, Tkach J. Oxygen‐17 contrast agents: fast imaging techniques. Invest Radiol 1988;23(Suppl 1): S240‐S242. Under physiologic conditions the stable isotope oxygen‐17, in the form of 0‐17 water, lowers the proton T2 of blood, CSF, tissues, and whole organisms. With MRI the resulting changes in intensity can be detected using spin‐echo pulse sequences, but much greater sensitivity is achieved in a fraction of the time with a steady‐state free precession sequence such as FISP. With this sequence it is possible to detect levels as low as 0.4% Oxygen‐17 water in 53 seconds or less.