phosphocreatine and Kidney-Neoplasms

Noninvasive investigation of renal metabolic changes is possible with 31P-MR, which is characterized by the determination of amounts of "free" phosphorus metabolites and intracellular pH and the possibility of measuring enzyme kinetics by the 31P-MR magnetization transfer method. 31P-MR has been extensively used to monitor such alterations in response to kidney ischemia, in which the ratios of anorganic phosphate to ATP and phosphomonoesters change drastically. The stages of ultrastructural ischemic renal damage can already be accurately classified with reference to a scale of 31P-MR-spectrum-derived renal function predictors. The recent application of MR high-resolution imaging may allow further improvement of organ viability assessment. The clinical use of combined MR imaging and spectroscopy is an essential and imminent step.

Topics: Adenosine Diphosphate; Adenosine Triphosphate; Animals; Energy Metabolism; Humans; Hydrogen-Ion Concentration; Kidney Diseases; Kidney Neoplasms; Kidney Transplantation; Magnetic Resonance Spectroscopy; Organ Preservation; Phosphates; Phosphocreatine; Rats

In vivo and in vitro 31P-NMR spectroscopy was used to study the high energy phosphate metabolism of VX-2 tumors implanted into rabbit liver, kidney, and hind-limb muscle. Tumors, at various stages of growth, were first examined by in vivo 31P-NMR spectroscopy, then they were excised and underwent histologic examination and biochemical analysis; both in vitro 31P-NMR and standard enzymatic techniques were used. There was good correlation among the in vivo NMR spectra, the in vitro NMR data, and the biochemical analyses. Although the tumor spectra showed characteristics similar to those reported in the other tumor models, there was a striking variability in the spectra obtained from tumors implanted in the same site and from different sites. There was poor correlation between the degree of necrosis in the tumor and the tumor pH and between the Pi:ATP ratio and necrosis. This variability has important implications for the potential value of using 31P-NMR spectroscopy to monitor tumor growth and therapy in vivo.

Topics: Adenosine Triphosphate; Animals; Carcinoma; In Vitro Techniques; Kidney Neoplasms; Liver Neoplasms; Magnetic Resonance Spectroscopy; Muscular Diseases; Neoplasms, Experimental; Phosphocreatine; Phosphorus; Rabbits

Topics: Acetoacetates; Acyltransferases; Adenocarcinoma; Adenosine Triphosphate; Animals; Fatty Acids, Nonesterified; Glucose; Glucose-6-Phosphatase; Glucosephosphate Dehydrogenase; Glutamates; Glycolysis; Hydroxybutyrate Dehydrogenase; Hydroxybutyrates; Iodoacetates; Ischemia; Ketone Bodies; Kidney; Kidney Neoplasms; Lactates; Malates; NAD; Neoplasms, Experimental; Oxidoreductases; Phosphocreatine; Pyruvates; Rats; Transferases