Modified Enzymatic Methods for the Determination of L-(+)-Lactic and Pyruvic Acids in Blood

Neville, John F.; Gelder, RL

doi:10.1093/ajcp/55.2.152

Cited by 26 publications

(8 citation statements)

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“…For neutralised PCA-treated perfusate samples lactate was estimated enzymatically, following the conversion of lactate to pyruvate and quantifying NADH absorbance at 340 nm [25]. Rates of lactate accumulation were estimated from timed collections of perfusate, and linear regression analysis of lactate synthesis used to estimate the rate of lactate production.…”

Section: Lactate Fluxmentioning

confidence: 99%

Changes to both cardiac metabolism and performance accompany acute reductions in functional capillary supply

Hui‐Kang

Winter

Alshammari

et al. 2015

Biochimica et Biophysica Acta (BBA) - General Subjects

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METHODS: Metabolism of substrates was measured before and after infusion of polystyrene microspheres in the perfused working heart to mimic random capillary loss due to microvascular disease. The effect of acute loss of functional capillary supply on palmitate and glucose metabolism together with function was quantified, and theoretical tissue oxygen distribution calculated from histological samples and ventricular VO 2 estimated.RESULTS: Microsphere infusion led to a dose-dependent decrease in rate-pressure product (RPP) and oxygen consumption (P<0.001). Microsphere infusion also increased work/unit oxygen consumption of hearts ('efficiency') by 25% (P<0.01). When corrected for cardiac work palmitate oxidation remained tightly coupled to very low workloads (RPP<2,500 mmHg/min), illustrating a high degree of metabolic control. Arteriole occlusion by microspheres decreased the density of patent capillaries (P<0.001) and correspondingly increased the average capillary supply area by 40% (P<0.01).Calculated rates of oxygen consumption declined from 16.6 ± 7.2 ml/100ml/min to 12.4 ± 9 ml/100ml/min following arteriole occlusion, coupled with increases in size of regions of myocardial hypoxia (Control = 22.0% vs. Microspheres = 42.2%).CONCLUSIONS: Cardiac mechanical performance is very sensitive to arteriolar blockade, but metabolite switching from fatty acid to glucose utilisation may also support cardiac function in regions of declining PO 2 .

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Section: Lactate Fluxmentioning

confidence: 99%

Changes to both cardiac metabolism and performance accompany acute reductions in functional capillary supply

Hui‐Kang

Winter

Alshammari

et al. 2015

Biochimica et Biophysica Acta (BBA) - General Subjects

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“…Various methods for the quantitation of pyruvate have been reported, such as enzyme-based amperometric biosensors [3-5], HPLC coupled with colorimetric and fluorimetric detection [6-8], and enzymatic assays with fluorescence [9, 10] or absorbance measurements [11-14]. Chromatographic methods require expensive equipment and, as pyruvate has no chromophore, pre-column or post-column derivatization is usually required.…”

Section: Introductionmentioning

confidence: 99%

A sensitive fluorimetric assay for pyruvate

Zhu

Romero

Petty

2010

Analytical Biochemistry

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A sensitive and specific fluorimetric assay for the determination of pyruvate is reported. This assay is based on the oxidation of pyruvate in the presence of pyruvate oxidase. Hydrogen peroxide generated by pyruvate oxidase reacts with non-fluorescent amplex red at a 1:1 stoichiometry to form the fluorescent product, resorufin. The assay is optimized with respect to pH of reaction buffer, enzyme concentration, dye concentration, and the time course. The usefulness of the assay is demonstrated by the accurate measurement of intracellular and extracellular pyruvate concentrations. The limit of detection (LOD) of the assay is 5 nM.

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“…Suspensions of brain were incubated in duplicate and the reaction was stopped by the addition of six drops of 4 N hydrochloric acid at 10,30,60, and 120 min . Lactate was measured enzymatically after centrifuging the suspensions at 5000 x g using the method of Neville and Gelder (29). Lactate production was calculated by substracting the lactate present before incubation and expressed as /Lmoles of lactate produced per gram brain per unit time.…”

Section: Methodsmentioning

confidence: 99%

Brain Carbohydrate Metabolism during Experimental Haemophilus influenzae meningitis

Moxon

1979

Pediatr Res

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SummaryFive-day-old infant rats which acquire Haemophilus intluenzae b bacteremia and meningitis after intranasal inoculation have a transient depression in weight gain (2 days), but then continue to grow at the same rate as strain U-ll inoculated controls. Brain lactate, glucose, and glycogen concentrations increase during the first 5 days of disease in infected animals. The increase in brain glycogen can be accounted for by an influx of glycogen containing polymorphonuclear leukocytes. The increased concentrations of glucose and lactate were found not to be due to a change in brain weight to dry weight ratio or the volume of entrapped blood. The mean cerebrospinal fluid (CSF) glucose concentration was higher in animals with meningitis (2.7 mM) in comparison to U-ll inoculated controls (1.8 mM). This increase in brain and CSF glucose concentration appeared secondary to an increased brain uptake of hexoses as manifested by an increased [3Hlmannitol uptake. Brain lactate accumulation was not explicable from the data available. There was no evidence of cerebral cortical ceUular damage because in vitro oxygen uptake and lactate production were equivalent in control and meningitic animals. The ability of the infant rat brain to maintain cerebral adenosine triphosphate (ATP) content in meningitis and the failure of CSF glucose concentration to decrease might be a reflection of the importance of alternative oxidative substrate (e.g., ,8-hydroxybutyrate) to the cerebral metabolism of the developing rat brain. Speculation iology of postmeningitic central nervous system sequelae is poorly understood.Hypoglycorrachia is observed in patients with pyogenic meningitis. Its mechanism is unclear, but it has been suggested that it results from abnormal cerebral glucose metabolism (23). In dogs with experimental pneumococcal meningitis the passive diffusion of mannitol from blood into CSF was increased 16-fold; however, net facilitated inward diffusion of 3-0-methylglucose was decreased, as was 3-0-methylglucose efflux. The methods used did not permit net balance studies, but the role of the brain in regulating CSF glucose concentration was not excluded. Because hypoglycemia or subarachnoid hemorrhage can be associated with abnormal cerebral glucose metabolism and is associated with permanent neurologic sequelae, we investigated cerebral carbohydrate metabolism in infant rats with H. injluenzae meningitis.These studies utilized an experimental model of H. injluenzae, type b, meningitis in infant rats in which the infection is produced by noninvasive intranasal inoculation of bacteria (27). The occurrence of meningitis can be predicted by the presence of bacteremia 48 hr postinoculation at a density of> 10 4 colony-forming units/rnl (26). In this model the histopathologic characteristics and CSF inflammatory response simulate those occurring in the human (26,27). In addition, postmeningitic survivors show a decreased rate of acquisition of operant conditioning (42) and decreased synaptogenesis and dendritic arborization (5). This...

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Modified Enzymatic Methods for the Determination of L-(+)-Lactic and Pyruvic Acids in Blood

Cited by 26 publications

References 0 publications

Changes to both cardiac metabolism and performance accompany acute reductions in functional capillary supply

Changes to both cardiac metabolism and performance accompany acute reductions in functional capillary supply

A sensitive fluorimetric assay for pyruvate

Brain Carbohydrate Metabolism during Experimental Haemophilus influenzae meningitis

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