Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0155339 (Brown)
 12,436 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We have previously found (P. B. Garlick, T. R. Brown, R. H. Sullivan and K. Ugurbil, J. Mol. Cell Cardiol. 15, 855-858 (1983)) that two peaks could be observed in the phosphate region of NMR spectra of isolated, perfused rat hearts. Upon valinomycin treatment, an increase in the peak at 2.8 ppm in the phosphate region (phosphocreatine set at -2.52 ppm) had been observed. We have now confirmed our hypothesis that this peak originates from the mitochondrial phosphate by: (i) determination of myocardial mitochondrial phosphate contents using density gradient centrifugation in non-aqueous solvents; and (ii) quantitative electron microscopy of the heart tissue. Thus, we conclude that mitochondrial and cytosolic phosphate can be distinguished from each other in 31P NMR spectra of isolated, perfused rat hearts.
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PMID:Evidence that mitochondrial phosphate is visible in 31P NMR spectra of isolated, perfused rat hearts. 155 Jul 7

Monitoring human cardiac allograft rejection is currently accomplished by endomyocardial biopsy. Available noninvasive methods for identifying rejection have lacked the necessary sensitivity or specificity, or both, for routine clinical application. In vivo phosphorus-31 (P-31) nuclear magnetic resonance (NMR) spectroscopy has been used for monitoring phosphorus metabolism in both animal models and humans. In the present study this technique was employed as a noninvasive means to assess the bioenergetic processes that occur during cardiac allograft rejection in a rat model. Brown Norway rat hearts were transplanted subcutaneously into the anterior region of the neck of Lewis rat recipients (allografts). Control isografts employed Lewis donors and recipients. Phosphocreatine to inorganic phosphate (PCr/Pi), phosphocreatine to beta-adenosine triphosphate (PCr/ATP beta), beta-adenosine triphosphate to inorganic phosphate (ATP beta/Pi) ratios and pH of the transplanted hearts were monitored using surface coil P-31 NMR spectroscopy (at 4.7 tesla) daily for 7 days. To allow recovery from the compromise induced by the surgical procedure, the measurements obtained on day 2 were taken as a baseline. PCr/Pi was unchanged or increased in the isografts but decreased continually in allografts, with the difference becoming significant by day 4 when compared with levels in day 2 allografts (p less than 0.005) and by day 3 when compared with levels in the isograft group (p less than 0.05). PCr/ATP beta in isografts did not change throughout the study; however, allografts demonstrated a significant decrease as early as day 3 (p less than 0.01), although a significant difference between isografts and allografts did not become manifest until day 4 (p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Monitoring the bioenergetics of cardiac allograft rejection using in vivo P-31 nuclear magnetic resonance spectroscopy. 355 75

Brown trout acclimated to soft water and exposed for 96 h to a sub-lethal concentration of copper at low pH (0.08 micromol l(-1) Cu, pH 5) have a lower critical swimming speed than fish from copper-free water at neutral pH. This loss of performance is not due to difficulties in oxygen transfer resulting from gill damage since arterial oxygen and carbon dioxide levels remain unaffected. Both red and white muscle showed some metabolic disruptions consistent with local hypoxia, namely a high lactate concentration at rest and, in the white muscle, depletion of glycogen and phosphocreatine. However, a putative role of increased blood viscosity following haematological changes in reducing the supply of oxygen to the tissues is not supported by the current study. Haematocrit, haemoglobin and plasma protein concentrations were not affected by this treatment and a lack of further change in variables such as lactate at the onset of exercise led one to look for an alternative explanation for the effects of copper and low pH upon tissue metabolites. Ammonia concentration, both in the plasma and muscles, is significantly higher in trout exposed to copper and low pH. Ammonia plays a role in the regulation of a number of metabolic pathways and could contribute to the altered metabolic status of these fish. In addition, ammonium ions are known to cause electrophysiological disruptions, particularly the displacement of K(+) in ion exchange mechanisms that could lead to the observed loss of swimming performance. Using the measured distribution of ammonia between intracellular and extracellular compartments to estimate membrane potential of resting muscle, a significant depolarisation is predicted in both red and white muscle of fish exposed to copper and low pH.
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PMID:Exposure of brown trout, Salmo trutta, to a sub-lethal concentration of copper in soft acidic water: effects upon muscle metabolism and membrane potential. 1106 28