ABSTRACT
The changes in the response of skeletal muscle to maximal dynamic exercise were investigated in going from a fasted state to a refed state by means of 31P NMR spectroscopy. It was found that in the fasted state, exercise-induced changes in Pi/PCr and in pH were both inhibited, in comparison with those in the refed state.
Subject(s)
Fasting , Muscles/metabolism , Phosphates/metabolism , Phosphocreatine/metabolism , Physical Exertion , Adenosine Triphosphate/metabolism , Adult , Female , Humans , Hydrogen-Ion Concentration , Male , Muscles/physiology , Physical Education and TrainingABSTRACT
Using CSF/protein solutions as models of vasogenic extracellular fluid, the concentration dependences of longitudinal and transverse proton relaxation rates have been measured at 37 degrees C and 100 MHz for the serum proteins, albumin, IgG, a 2.8:1 mixture of albumin and IgG and human serum itself. These measurements have been used to determine the sensitivity of proton relaxation rates to the amount and the type of the protein in oedema fluid, and to establish the significance of both of these factors in relation to a separation of vasogenic from cytotoxic oedema. An extension of the two-environment rapid-exchange model of solvent relaxation is presented, which accounts for the measurements on protein mixtures and which enables estimates to be made of the number and the transverse relaxation rate of water protons associated with the protein surface.
Subject(s)
Brain Edema/diagnosis , Cerebrospinal Fluid Proteins/analysis , Humans , Immunoglobulin G/analysis , Magnetic Resonance Spectroscopy , Mathematics , Models, Neurological , Serum Albumin/analysisABSTRACT
A hexafluorinated 2-nitroimidazole (CCI-103F) has been synthesized and its properties as a hypoxic cell binder investigated. The drug has a plasma half-life of 90 min in Balb/C mice and a tumor-to-plasma ratio of 0.8. Following sustained exposure to the drug and a washout period for the unbound drug, liver and tumor samples were excised. NMR investigation of the excised tissue in a 2.35 T animal sized NMR facility revealed the presence of 19F bound to both tissues. Further improvement in sensitivity is required to make 19F NMR detection of binding in situ feasible.
Subject(s)
Magnetic Resonance Spectroscopy , Neoplasms, Experimental/metabolism , Nitroimidazoles/metabolism , Animals , Mice , Mice, Inbred BALB C , Neoplasm Transplantation , Oxygen/physiologyABSTRACT
The spin-lattice relaxation rates (1/T1) were measured at 94.1 MHz for six peaks in the 19F NMR spectrum of the perfluorochemical blood substitute fluosol-DA, which contains a mixed emulsion of perfluorodecalin and perfluorotripropylamine. Each of these rates increased linearly with the percentage of oxygen dissolved in the emulsion. Relative values of the linear increase for different peaks established that, for perfluorotripropylamine in the mixed emulsion, the oxygen-fluorocarbon interaction is loosely but preferentially oriented in a manner similar to that previously established for other pure fluorocarbons. The uncertainty in the oxygen level estimated from T1 measurements is somewhat less than 5% O2 and it is thus established that quantitative non-invasive oxygenation measurements can be made to sufficient precision by this approach, using fluosol-DA and 19F spin-lattice relaxation.
