Lactate Ions Research Articles

Influence of lactate ions on the formation of rust

The formation of rust can be simulated by oxidation of aqueous suspensions of Fe(OH) 2 obtained by mixing solutions of NaOH and a Fe(II) salt. The aim of this study was to investigate the influence of organic species associated with microbially influenced corrosion. The lactate anion, often used as a carbon and electrons source for the development of microorganisms, was chosen as an example. Then, in the first part of the study, Fe(OH) 2 was precipitated using iron(II) lactate and NaOH. Its oxidation process involved two stages, as usually observed. The first stage led to a Fe(II–III) intermediate compound, the lactate green rust, GR ( C 3 H 5 O 3 - ) . This compound has never been reported yet. Its existence demonstrates that the GR structure is able to incorporate a very wide range of anions, whatever the size and geometry. The second stage corresponded to the oxidation of GR ( C 3 H 5 O 3 - ) . It led to ferrihydrite, the most poorly ordered form of iron(III) oxides and oxyhydroxides. In the second part of the study, the formation of rust in seawater was simulated by oxidation of Fe(OH) 2 in an aqueous media containing both Cl − and SO 4 2 - anions. The first stage led to the sulphate green rust, GR ( SO 4 2 - ) , the second stage to lepidocrocite γ-FeOOH. Small amounts of iron(II) lactate were added to the reactants. Lactate ions did not modify the first stage but drastically perturbed the second stage, as ferrihydrite was obtained instead of γ-FeOOH.

Potassium kinetics and its relationship with ventilation during repeated bouts of exercise in women

The purpose of this study was to determine the electrolyte concentration changes in arterial plasma from high-intensity repeated bouts of cycling exercise in well-trained females and to determine the relationships between arterial plasma lactate, potassium (K+), bicarbonate (HCO3(-)), and pH with minute ventilation. Fourteen female subjects (mean age = 27 +/- 4 years; mean height = 170 +/- 7 cm; mean weight = 62 +/- 7 kg; maximal oxygen uptake = 50 +/- 6 ml/kg/min) were recruited to perform 3 x 5 min bouts of exercise at 236 +/- 27 W with 10 min recovery between each set. Minute ventilation, arterial plasma lactate, potassium, calcium, chloride, and sodium ion concentrations were measured a minute 0, 1, 2, 3, 4, 5 of each set and midway through recovery (21 sampling points total per subject). The results showed that the strongest relationship was between arterial plasma K+ concentration and minute ventilation (r2 = 0.91), and, that arterial plasma lactate mirrored both arterial plasma HCO3(-) and pH. In conclusion, this study demonstrates that women exhibit similar electrolyte responses as reported elsewhere in men, and support the idea that K+ may partly contribute to controlling ventilation during high-intensity exercise and recovery.

Acid-Base Balance during Continuous Veno-Venous Hemofiltration: The Impact of Severe Hepatic Failure

Continuous renal replacement therapy (CRRT) affects acid-base balance but the influence of severe hepatic failure (SHF) on this effect is unknown. To assess the effect of SHF on acid-base balance in patients receiving CVVH. Retrospective laboratory investigation. Forty patients with SHF and acute renal failure (ARF) treated with CVVH and 42 critically ill patients with severe ARF but no liver disease also treated with CVVH (controls). Retrieval of clinical and laboratory data from prospective unit and laboratory databases. Quantitative acid-base status assessment using the Stewart-Figge methodology. Comparison of findings between the two groups. Although CVVH had a major effect on acid base balance in both groups, patients with SHF had a higher mean lactate concentrations (4.8 vs. 3.1 mmol/L; p<0.0005), a greater base deficit compared to controls (-1 vs. 4.1 mEq/L; p<0.0001) and a lower PaCO 2 tension (36.8 vs. 42.5 mmHg; p<0.0001), despite the use of bicarbonate replacement fluid. The acidifying effect of hyperlactatemia was slightly worsened by an increased strong ion gap (9.3 vs. 4.9 mEq/L; p<0.0001). It was, however, attenuated by an increased strong ion difference apparent (SIDa) (43.6 vs. 41.9 mEq/L; p<0.05) secondary to hypochloremia (96 vs. 100 mmol/L; p<0.0001) and by hypoalbuminemia, although hypoalbuminemia in SHF patients (26 vs. 23; p<0.005) was less pronounced than in controls. The use of CVVH does not fully correct the independent acidifying effect of liver failure on acid-base status. Increased lactate and strong ion gap values maintain a persistent base deficit despite the alkalinizing effects of hypoalbuminemia and hypochloremia. The correction of acidosis in SHF patients may require more intensive CVVH.

Point:Counterpoint: Lactic acid accumulation is an advantage/disadvantage during muscle activity

Point:Counterpoint: Lactic acid accumulation is an advantage/disadvantage during muscle activity

Decontamination of deboned chicken legs by vacuum‐tumbling in lactic acid solution

SummaryVacuum tumbling in a 1–5% lactic acid solution for a short time (1–10 min) improves the microbiological quality of deboned chicken legs, while inducing a light acidification and water absorption. The most significant variable of the process is the tumbling speed. High tumbling speeds lead to a high decontamination level of the chicken legs with regard to total viable counts and Enterobacteriaceae. Sodium lactate alone is unable to induce any decontamination at the same concentrations. Decontamination is probably more linked to acidification than to lactate ions. The use of vacuum tumbled (1 min in a 1% lactic acid solution) deboned chicken legs in the industrial manufacture of fresh chicken sausages led to a clear decrease in the number of Salmonella‐positive batches. The incidence of positive batches was reduced threefold and the acid decontamination process did not adversely affect the sensory quality of the sausages.

SODIUM BICARBONATE AND SODIUM CITRATE

Numerous studies have used exogenous administration of sodium bicarbonate (NaHCO3) and sodium citrate (Na-citrate) in an attempt to enhance human performance. After ingestion of NaHCO3 and Nacitrate, two observations have been made: (a) There was great individual variability in the ergogenic benefit reached, which can be attributed to the level of physical conditioning of the subjects and to their tolerance of the buffer substance; and (b) the subjects who had ingested NaHCO3 and Na-citrate show higher levels of pH, bicarbonate, and lactate ions concentrations in their exercising blood than do the subjects who had ingested the placebo. A majority of the studies have suggested that the ingestion of both substances provides an ergogenic effect due to the establishment and maintenance of an elevated pH level during exercise. However, the exact mechanism by which the ergogenic effects occur has not been demonstrated conclusively. Sodium bicarbonate and Na-citrate seem to be effective in activities with a sufficient duration to generate a difference in the hydrogen ion gradient, characterized by a very high intensity and involving large muscular groups. However, in activities of equally high intensity, but with longer duration, the results obtained have been conflicting and inconclusive.

Sodium Bicarbonate and Sodium Citrate: Ergogenic Aids?

Numerous studies have used exogenous administration of sodium bicarbonate (NaHCO(3)) and sodium citrate (Na-citrate) in an attempt to enhance human performance. After ingestion of NaHCO(3) and Na-citrate, two observations have been made: (a) There was great individual variability in the ergogenic benefit reached, which can be attributed to the level of physical conditioning of the subjects and to their tolerance of the buffer substance; and (b) the subjects who had ingested NaHCO(3) and Na-citrate show higher levels of pH, bicarbonate, and lactate ions concentrations in their exercising blood than do the subjects who had ingested the placebo. A majority of the studies have suggested that the ingestion of both substances provides an ergogenic effect due to the establishment and maintenance of an elevated pH level during exercise. However, the exact mechanism by which the ergogenic effects occur has not been demonstrated conclusively. Sodium bicarbonate and Na-citrate seem to be effective in activities with a sufficient duration to generate a difference in the hydrogen ion gradient, characterized by a very high intensity and involving large muscular groups. However, in activities of equally high intensity, but with longer duration, the results obtained have been conflicting and inconclusive.

Control of glycolysis in mature boar spermatozoa: effect of pH in vitro.

The glycolytic pathway in boar sperm is sensitive to pH, which decreases as lactate is produced from either glucose or fructose in vitro. The build up of lactate appears to be due to the saturation of mitochondrial lactate transporters, which causes the cytoplasmic pH to fall. Phosphofructokinase has been shown to be sensitive to this drop in pH rather than to the build up of lactate ions or ATP, thereby controlling the rate of glycolysis in vitro.

Factors affecting solubility of calcium lactate in aqueous solutions.

Calcium lactate (CaL2) crystal formation on the surface of cheese continues to be a widespread problem for the cheese industry despite decades of research. To prevent those crystals from forming, it is necessary to keep the concentration of CaL2 below saturation level. The limited data available on the solubility of CaL2 at conditions appropriate for the storage of cheese are often conflicting. In this work, the solubility of L(+)-CaL2 in water was evaluated at 4, 10, and 24 degrees C, and the effects of salt and pH at those temperatures were investigated. The effects of additional calcium and lactate ions on solubility also were studied. The results suggested that temperature and the concentration of lactate ions are the main factors influencing the solubility of CaL2, with the other parameters having limited effect.

Metabolic inertia in contracting skeletal muscle: a novel approach for pharmacological intervention in peripheral vascular disease.

Peripheral vascular disease (PVD) is generally accepted to result in the failure of skeletal muscle blood flow to increase adequately at the onset of muscular work. There are currently no routine pharmacological interventions towards the treatment of PVD, however, recent Phase III trials in the USA have demonstrated the clinical potential of the phosphodiesterase III inhibitor Cilostazol for pain-free and maximal walking distances in patients with intermittent claudication. PVD is characterized by a marked reliance on oxygen-independent routes of ATP regeneration (phosphocreatine hydrolysis and glycolysis) in skeletal muscle during contraction and the rapid onset of muscular pain and fatigue. The accumulation of metabolic by-products of oxygen-independent ATP production (hydrogen and lactate ions and inorganic phosphate) has long been associated with an inhibition in contractile function in both healthy volunteers and PVD patients. Therefore, any strategy that could reduce the reliance upon ATP re-synthesis from oxygen-independent routes, and increase the contribution of oxygen-dependent (mitochondrial) ATP re-synthesis, particularly at the onset of exercise, might be expected to improve functional capacity and be of considerable therapeutic value. Historically, the increased contribution of oxygen-independent ATP re-synthesis to total ATP generation at the onset of exercise has been attributed to a lag in muscle blood flow limiting oxygen delivery during this period. However, recent evidence suggests that limited inertia is present at the level of oxygen delivery, whilst considerable inertia exists at the level of mitochondrial enzyme activation and substrate supply. In support of this latter hypothesis, we have reported on a number of occasions that activation of the pyruvate dehydrogenase complex, using pharmacological interventions, can markedly reduce the dependence on ATP re-synthesis from oxygen-independent routes at the onset of muscle contraction. This review will focus on these findings and will highlight the pyruvate dehydrogenase complex as a novel therapeutic target towards the treatment of peripheral vascular disease, or any other disease state where premature muscular fatigue is prevalent due to metabolite accumulation.

Control of glycolysis in mature boar spermatozoa: effect of pH in vitro

The glycolytic pathway in boar sperm is sensitive to pH, which decreases as lactate is produced from either glucose or fructose in vitro. The build up of lactate appears to be due to the saturation of mitochondrial lactate transporters, which causes the cytoplasmic pH to fall. Phosphofructokinase has been shown to be sensitive to this drop in pH rather than to the build up of lactate ions or ATP, thereby controlling the rate of glycolysis in vitro.

Monitoring of water content and water distribution in ischemic hearts

We determined water content and water distribution by fitting dielectric spectra of ischemic canine hearts between 5 MHz and 3 GHz with a newly developed model which describes heart cells and subcellular organelles as rotational ellipsoids filled with electrolyte enclosed by an isolating membrane. The fraction of dry material is modelled by spherical particles with a small dielectric permittivity. Free model parameters were water content, cell volume fraction, and the conductivity of the electrolytes. Resulting model parameters were compared to data from tissue desiccation and to conductivity changes produced by protons and lactate ions. We investigated hearts in two states: during ischemia after interruption of blood flow (pure ischemia, PI, n=5) and during ischemia after resuscitation with Tyrode's solution (IAR, n=14). The difference between water content determined by tissue desiccation and by dielectric spectroscopy was less than 0.5%. During 360 min of ischemia, water content in IAR decreased from 85±1.6% to 83±2.2% and in PI from 80±0.8% to 78±1.5%. Cellular volume fraction in IAR increased from 0.47±0.045 to 0.63±0.031 and in PI from 0.62±0.014 to 0.73±0.013, which is consistent with published morphometric data. After 180 min of ischemia, the increase of the cytosolic conductivity was 0.14±0.02 S/m as calculated from the dielectric spectrum and was similar to the conductivity increase which was roughly estimated on the basis of tissue lactate concentration. In conclusion, dielectric spectroscopy combined with our model analysis facilitates the monitoring of water content and distribution by means of nondestructive surface probes.

Comparative characterization of growth and recombinant protein production among three insect cell lines with four kinds of serum free media

Three insect cell lines, Sf9, Sf21 and Tn5B1-4, and four different kinds of serum free media (SFM), Sf 900 II, EX-CELL 420, EX-CELL 405 and Express Five, were used to compare the nutrient consumption, byproduct formation, production of recombinant protein and protease activity in suspension cultures. The Sf 900 II SFM was appropriate for the cell growth and protein production of the Sf9 and Sf21 cell lines. When the Tn5B1-4 cell line was grown in the Express Five SFM, the specific growth rate was 1.6 fold higher than those of either the Sf9 or Sf21 cell lines. The glucose and glutamine consumption rates per cells, were 4 and 2.3. times higher than those of the Sf9 cell line, respectively. The overall yield coefficients of the lactate and ammonium ion were 2.8 and 1.5 times higher compared to those of the Sf9 cell line, respectively. The maximum specific β-galactosidase production rate was 4.5. fold that of the Sf9 cell line, a 3 times higher protease activity per cell.

Cotransport of H +, lactate, and H 2O in porcine retinal pigment epithelial cells

The retinal pigment epithelium (RPE) of the eye transports water and lactate ions in the direction from retina to choroid. The water transport is important in maintenance of retinal adhesion and the transport of lactate ions serves to regulate the lactate levels and pH of the subretinal space. This study investigates by means of a non-invasive technique the mechanism of coupling between transport of H +, lactate ion, and water in the monocarboxylate transporter (MCT1) located in the apical (retinal) membrane of a mammalian RPE. Primary cultures of porcine RPE cells were grown to confluence and placed in a perfusion chamber in which the solution facing the retinal membrane could be changed rapidly. Two types of experiments were performed: Changes in cell water volume were measured by self-quenching of the fluorescent dye Calcein, and changes in intracellular pH were measured ratiometrically using the fluorescent dye BCECF. In lactate-free solutions, mannitol addition to the retinal bath caused intracellular acidification and cell shrinkage, given by a single osmotic water permeability of 1·2±0·1×10 −4 cm sec −1 (osmol l −1) −1. In solutions containing 50 mmol l −1 lactate, however, the mannitol-induced cell shrinkage was faster and the cells alkalinized. These effects were not linear functions of the magnitude of the imposed osmotic gradients: Both volume effects and changes in intracellular pH showed apparent saturation with increasing gradients. Abrupt isosmotic replacement of Cl − with lactate in the concentration range from 3 to 50 mmol l −1 caused an immediate cell swelling as well as an immediate intracellular acidification; both effects showed apparent saturation with increasing lactate concentration. The K m values were: 11±2 mmol l −1 for the water fluxes and 13±4 mmol l −1 for the H + and lactate fluxes. The data suggest that H 2O is cotransported along with H + and lactate ions in MCT1 localized to the retinal membrane. The study emphasizes the importance of this cotransporter in the maintenance of water homeostasis and pH in the subretinal space of a mammalian tissue and supports our previous study performed by an invasive technique in an amphibian tissue.

Diastereomeric salts of lactic acid and 1-phenylethylamine, their structures and relative stabilities.

Crystal structures have been determined for the two diastereomeric salts formed between S-lactic acid (S-LA) and 1-phenylethylamine (PEA). The relative stabilities of the salts have been investigated by differential scanning calorimetry and solubility measurements in acetonitrile. The less soluble salt obtained from water, (R-PEA)(S-LA), is the less dense. It belongs to the orthorhombic space group P2(1)2(1)2(1), Z = 4. The more soluble salt, (S-PEA)(S-LA) x H(2)O, crystallized from ethanol is monoclinic, space group P2(1), Z = 2. The crystal structure showed that the water molecule is well integrated into the hydrogen-bond network in the more soluble salt, which explains the fruitless attempts made to obtain the corresponding unhydrated salt. The lactate ion adopts different conformations in the two salts. The relative energies were investigated by Hartree-Fock calculations, showing that the lactate ion is in a conformation with higher energy in the more soluble salt. The difference in solubility between the two salts can be attributed to an interplay of enthalpy and entropy effects.

Determination of stoichiometric dissociation constants of lactic acid in aqueous salt solutions at 291.15 and at 298.15 K

Equations were determined for the calculation of the stoichiometric (molality scale) dissociation constant, K m, of lactic acid in aqueous salt solutions at 291.15 and 298.15 K from the thermodynamic dissociation constant, K a, of this acid and from the ionic strength, I m, of the solution. The salt alone determines mostly the ionic strength of the solutions considered in this study, and the equations for K m were based on the single-ion activity coefficient equations of the Hückel type. New data measured by potentiometric titrations in a glass electrode cell at 298.15 K and the literature data obtained by Larsson and Adell with quinhydrone (qh) electrode cells at 291.15 K were used in the estimation of the parameters for the Hückel equations (HE) of lactate ions in NaCl and KCl solutions. The Harned cell data measured at 298.15 K by Nims and Smith were used to obtain the activity parameters for lactate ions in dilute LiCl, BaCl 2 and SrCl 2 solutions. The conductance data measured at 298.15 K by Martin and Tartar were used to determine the thermodynamic value of the dissociation constant of lactic acid. By means of the calculation method suggested in this study, K m can be obtained almost within experimental error at least up to I m of about 0.5 mol kg −1 for lactic acid in NaCl and KCl solutions at the two temperatures considered. The K m values obtained by this method were compared to those obtained by the calculation methods presented recently in the literature for a general treatment of thermodynamics of weak acids in NaCl and KCl solutions.

Renal manifestations of congenital lactic acidosis.

Congenital lactic acidoses (CLAs) constitute a group of rare inborn errors of mitochondrial metabolism in which cellular energy failure is the defining biochemical abnormality. We report the principal manifestations of renal dysfunction in 35 children with CLA caused by defects in either the pyruvate dehydrogenase multienzyme complex or one or more components of the respiratory chain. The most prominent renal abnormalities included bicarbonaturia, phosphaturia, hypercalciuria, complete Fanconi's syndrome, proteinuria, and decreased glomerular filtration rate. These data were compared with those from 79 previously published cases. Clinical manifestations of renal dysfunction in CLA are common and may be the first presenting sign of the disease. The glomerulus and proximal renal tubule appear to be the anatomic sites most vulnerable to abnormal mitochondrial energy transduction. We propose that the primary defect in mitochondrial energy metabolism, together with the consequent intracellular accumulation of lactate and hydrogen ions, precipitates a state of tissue injury that, unless interrupted, becomes self-perpetuating and ultimately leads to renal cell death.

Ammonium 2,7-dimethyl-5-bora-1,4,6,9-tetroxaspiro[4.4]nonane-3,8-dionate (ammonium borodilactate)

In the title compound, NH4+·C6H8BO6−, the trivalent boron is tetrahedrally bonded to four O atoms of the two lactate ions having a chiral carbon in each. Two of the O atoms are covalently bonded [1.4259 (13) Å] to the boron, while there is an extended B—O bonds [1.5177 (14) Å] between the boron and each of the other two O atoms. There are distortions in the tetrahedral angles around boron ranging from 104.47 (5) to 115.35 (15)°. The structure is stabilized by a network of N—H⋯O hydrogen bonds involving the H atoms of the ammonium cation and the O atoms of the borodilactate anion. The UV–vis transmittance window of this non-linear optical crystal is in the range 240–1250 nm.

Lactate supply as a determinant of the distribution of intracellular pH within the hepatic lobule

When isolated livers from starved rats are perfused with lactate at constant perfusate pH and Pco2, there is a marked gradient of cell pH (pHi) along the length of the lobular radius, with periportal cells being substantially more alkaline than perivenous cells. In the present studies, the perivenous 21% of the lobular volume was destroyed by retrograde digitonin perfusion, and antegrade perfusion restored. pHi was determined by 31P-NMR. The remaining periportal cells, the site of gluconeogenesis from lactate, had a substantially higher mean pHi (7.42) than did the intact liver (7.23). When lactate was removed from the perfusate, mean pHi decreased to 7.25. The corresponding concentration of cell bicarbonate fell with a half-time of approximately 5min. When lactate was re-introduced mean pHi rose to 7.34. We conclude that a major contributor to periportal alkalinity under these conditions is proton consumption during gluconeogenesis from lactate ions.

Lactate supply as a determinant of the distribution of intracellular pH within the hepatic lobule.

When isolated livers from starved rats are perfused with lactate at constant perfusate pH and P(co(2)), there is a marked gradient of cell pH (pH(i)) along the length of the lobular radius, with periportal cells being substantially more alkaline than perivenous cells. In the present studies, the perivenous 21% of the lobular volume was destroyed by retrograde digitonin perfusion, and antegrade perfusion restored. pH(i) was determined by (31)P-NMR. The remaining periportal cells, the site of gluconeogenesis from lactate, had a substantially higher mean pH(i) (7.42) than did the intact liver (7.23). When lactate was removed from the perfusate, mean pH(i) decreased to 7.25. The corresponding concentration of cell bicarbonate fell with a half-time of approximately 5 min. When lactate was re-introduced mean pH(i) rose to 7.34. We conclude that a major contributor to periportal alkalinity under these conditions is proton consumption during gluconeogenesis from lactate ions.