phosphorus-radioisotopes and Acidosis

To investigate the effects of 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (carboxy-PTIO), a nitric oxide scavenger, on the lipopolysaccharide-induced hypotension, hepatocellular dysfunction, and liver damage in endotoxic rabbits.. Experimental, comparative study.. Laboratory of a university hospital.. Eighteen Japanese white rabbits (3.0 to 3.2 kg body weight) anesthetized with ketamine-xylazine were studied.. We randomly divided the rabbits into three groups: saline controls (group 1, n = 5); animals receiving lipopolysaccharide (400 micrograms/kg) alone (group 2, n = 8); and animals receiving lipopolysaccharide plus carboxy-PTIO at a rate of 0.17 mg/kg/min for 3 hrs (group 3, n = 5). Blood gases and mean arterial pressure (MAP) were monitored. In vivo phosphorus-31 magnetic resonance spectra were continuously obtained every 30 mins. In addition, the livers were sampled and underwent fractionation at 7 hrs after lipopolysaccharide administration. The hydrophilic and hydrophobic extracts from the livers were analyzed by in vitro hydrogen-1 and phosphorus-31 magnetic resonance spectroscopy.. After the administration of lipopolysaccharide, the first phase of decrease in MAP within 30 mins was followed by partial recovery within the next 30 mins. In group 2, MAP started to decrease progressively within 180 mins after lipopolysaccharide administration (second phase) and decreased by 33% from the baseline value to 49 +/- 9 mm Hg at 420 mins. In contrast, the infusion of carboxy-PTIO significantly attenuated the second decrease in MAP (68 +/- 10 mm Hg, at 420 mins). In group 2, a slow and progressive decrease in adenosine triphosphate (ATP) and increase in inorganic phosphate concentrations occurred from 120 mins after lipopolysaccharide administration, and continued throughout the observation period. These changes were accompanied by a progressive decrease in intracellular pH. On the other hand, in group 3, there were no significant changes in ATP and inorganic phosphate concentrations compared with the controls from 120 to 360 mins after lipopolysaccharide administration. Moreover, restorations of both arterial and hepatocellular acidosis were observed in group 3. The differences of the degree of liver damage--as determined by the total amount of phospholipid, free fatty acids concentration, and membrane fluidity--were not significant among the three groups. Three of eight rabbits in group 2 died within 7 hrs, but no animal in the other two groups died during the study.. The results of this study indicate that the infusion of carboxy-PTIO: a) prevented the delayed hypotension associated with endotoxic shock in rabbits; b) returned the hepatocellular ATP concentrations nearly to the level of the controls and alleviated hepatocellular acidosis; c) normalized various hydrophilic metabolites, such as lactate and alanine in the liver; and d) did not exacerbate liver injury after the administration of lipopolysaccharide. These findings indicate that carboxy-PTIO, a nitric oxide scavenger, may have a positive vasopressor effect during hypodynamic septic shock without exacerbating liver injury.

Topics: Acidosis; Adenosine Triphosphate; Animals; Benzoates; Blood Pressure; Free Radical Scavengers; Hydrogen; Hypotension; Imidazoles; Lipopolysaccharides; Liver; Magnetic Resonance Spectroscopy; Nitric Oxide; Phosphates; Phosphorus Radioisotopes; Rabbits; Shock, Septic

31P NMR brain spectra were obtained from piglets over a range of mild hypocarbia to severe hypercarbia (PaCO225 to 198 mm Hg). The chemical shifts of the phosphoethanolamine and inorganic phosphate were used to calculate intracellular brain pH (pHet and pHpi, respectively). Both pHpi and pHet underwent parallel significant decreases during hypercarbia, corresponding to 51 and 53% pHregulation, respectively. We conclude that the chemical shift of the phosphomonoester peak in vivo can be used to measure decreases in intracellular pH in neonatal brain.

Topics: Acidosis; Animals; Animals, Newborn; Brain; Carbon Dioxide; Ethanolamines; Magnetic Resonance Spectroscopy; Partial Pressure; Phosphorus Radioisotopes; Swine

The effect of metabolic acidosis on the intestinal absorption of calcium (Ca) and phosphorus (P), plasma vitamin D metabolites and urinary excretion of Ca in adult rats treated with a small dose of 1,25(OH)2D3 were investigated. The rats in the experimental group received 1.8% ammonium chloride (NH4Cl) and a commercial chow, and their pair-fed controls received 0.45% NaCl. Both groups were given subcutaneously 1,25(OH)2D3. Intestinal absorption of Ca and P was measured by gut sac uptake of 45Ca and 32P. In the acidotic rats, duodenal, jejunal and ileal 45Ca uptake as well as jejunal and ileal 32P uptake were significantly increased. Plasma 1,25(OH)2D, 25(OH)D and 24,25(OH)2D were similar in both groups. 1,25(OH)2D3 treatment induced a greater calciuria in acidotic rats and increased their fractional excretion (FE) of Ca. An additional experiment showed increased 45Ca uptake by duodenum at a pH of 7.0 compared to pH 7.4. The present study suggests that NH4Cl-induced metabolic acidosis may enhance the effect of 1,25(OH)2D3 on intestinal absorption of Ca and P in the rat. However, the data from the study cannot exclude the possibility that acidosis may have a direct, vitamin D-independent effect on the intestine.

Topics: Acidosis; Animals; Calcitriol; Calcium; Calcium Radioisotopes; Glomerular Filtration Rate; Intestinal Absorption; Intestine, Small; Male; Phosphates; Phosphorus Radioisotopes; Rats; Rats, Inbred Strains

Topics: Acidosis; Animal Feed; Animals; Cattle; Cattle Diseases; Edible Grain; Male; Phosphorus; Phosphorus Radioisotopes; Poaceae

A 16-year-old boy with myopathy, ophthalmoplegia, and raised basal metabolic rate was examined by the non-invasive technique of phosphorus-31 nuclear magnetic resonance (31 P NMR). The muscles of the forearm showed an abnormal 31P NMR spectrum with a high inorganic phosphate (Pi) content in relation to phosphocreatine (PCr) (PCr/Pi = 4; control = 10). This finding was compatible with the abnormality of mitochondrial function already established by biopsy and offers in addition an explanation for the raised oxygen consumption in this patient. The method of 31P NMR is suited to rapid non-invasive diagnosis in various muscle disorders.

Topics: Acidosis; Adolescent; Humans; Hydrogen-Ion Concentration; Lactates; Magnetic Resonance Spectroscopy; Male; Mitochondria, Muscle; Muscular Diseases; Oxygen Consumption; Phosphates; Phosphocreatine; Phosphorus Radioisotopes

Previous studies from this laboratory utilized mass spectrometry to measure myocardial oxygen (PO2) and carbon dioxide (PCO2) tensions in isolated feline hearts subjected to periods of global ischemia and reperfusion. Myocardial carbon dioxide tension was found to increase during ischemia, and its rate of increase was found to correlate inversely with subsequent recovery of myocardial function following reflow. The present study utilized phosphorus-31 nuclear magnetic resonance (NMR) to assess whether the severity of intracellular acidosis or the depletion of high energy phosphate stores would show a similar correlation with recovery of function. Hyperkalemic cardioplegia employed as a myocardial preservation technqiue in combination with hypothermia was compared with hypothermia alone as the control intervention. The experimental results demonstrated that intracellular pH fell to 6.09 +/- 0.13 with hypothermia alone and to 6.31 +/- 0.09 with cardioplegia plus hypothermia. Furthermore, myocardial ATP content fell to 22% +/- 2% of control with hypothermia alone, while falling to 36% +/- 4% of control with the combined therapy. Recovery of myocardial performance was found to correlate inversely with the severity of intracellular acidosis and depletion of ATP during ischemia. In contrast, no relationship was observed between preservation of phosphoryl-creatinine levels either during ischemia or after reflow and recovery of ventricular function. These results suggest that, similar to mass spectrometry, which allows monitoring of myocardial PCO2, 31P NMR permits the on-line monitoring of intracellular pH as well as high energy phosphate compounds, and thereby provides useful metabolic indices of the severity of ischemia. Since tight coupling was found between changes in these parameters and subsequent recovery of contractile performance, further development of 31P NMR for evaluation of techniques designed to minimize the severity of ischemic damage would seem indicated.

Topics: Acidosis; Animals; Carbon Dioxide; Coronary Disease; Heart Arrest, Induced; Hypothermia, Induced; Magnetic Resonance Spectroscopy; Mass Spectrometry; Myocardium; Organophosphorus Compounds; Phosphorus Radioisotopes; Rabbits

Topics: Acidosis; Anesthesia, Inhalation; Animals; Bile; Blood; Blood Volume; Bupivacaine; Chromatography, Thin Layer; Erythrocytes; Ethyl Ethers; Female; Hematocrit; Hydrogen-Ion Concentration; In Vitro Techniques; Infusions, Parenteral; Iodine Radioisotopes; Male; Phosphorus Radioisotopes; Rabbits; Time Factors; Tritium