For quantification of [sup.13]C metabolites, the ratio of lactate-to-pyruvate and lactate-to-total carbon (tC: sum of lactate, pyruvate-hydrate, alanine, and pyruvate) was calculated.
Interestingly, the ratio of lactate-to-pyruvate in the non-enhancing [T.sub.2] lesion from this study (0.70 [+ or -] 0.24) was significantly smaller than that of enhancing tumor from supratentorial orthotopic glioblastoma xenografts in a previous study (1.0 [+ or -] 0.36) (p < 0.02, unpaired t-test), while it remained similar between contralateral brainstem tissue (0.28 [+ or -] 0.11) and contralateral supratentorial brain tissue (0.29 [+ or -] 0.17) .
(1985) Lactate, pyruvate, and lactate-to-pyruvate
ratio during exercise and recovery.
Extracellular Levels of Glutamate, Lactate-to-Pyruvate Ratio, Glycerol, Nitric Oxide, and Hydroxyl Radicals in the Hypothalamus.
For measurement of glutamate, lactate-to-pyruvate ratio, and glycerol, the dialysates were injected onto a CMA600 microdialysis analyzer (Carnegie Medicine, Stockholm, Sweden).
Melatonin Reduces Heat-Induced Increased Levels of Glutamate, Lactate-to-Pyruvate Ratio, Glycerol, Nitrite (NO), and Dihydroxybenzoic Acid (DHBAs) in the Hypothalamus.
Using the same principle (UV spectrometric monitoring of pyridine coenzyme oxidation), LDH activity can be measured by either the lactate-to-pyruvate
reaction (LP, forward reaction) or the pyruvate-to-lactate reaction (PL, backward reaction).
Based on their own experiments spiking LDH and lactate into ethanol-free serum specimens, Siemens informed us that that to generate a spurious ethanol result >80 mg/dL (17.4 mmol/L), LDH would have to be > 100 000 U/L (by a lactate-to-pyruvate
methodology) in the presence of a lactate concentration above the normal reference interval (correspondence from Siemens).
The blood lactate-to-pyruvate (L:P)  molar ratio reflects the equilibrium between product and substrate of the reaction catalyzed by lactate dehydrogenase.
 Nonstandard abbreviations: L:P, lactate-to-pyruvate; PDH-D, pyruvate dehydrogenase deficiency; CLA, congenital lactic acidosis; PDH, pyruvate dehydrogenase; mtDNA, mitochondrial DNA.
The IFCC (4) recommends the lactate-to-pyruvate
conversion, for which the optimum pH is 8.8-9.8.