L-lactate Concentration Research Articles

Abstract 51: Role of MUC13 as non-hypoxic stimuli inducing HIF-1α in pancreatic cancer under normoxia

Abstract Objective: Pancreatic cancer is the fourth most common cause of deaths occurring due to cancer, with an overall survival rate of just 5%. MUC13, a transmembrane mucin, is aberrantly expressed in pancreatic cancer, while an altered glucose metabolism is known to facilitate cancer cell survival and proliferation. Hypoxia-inducible factor 1 α (HIF-1 α) plays an important role in reprogramming of cancer cell metabolism by activating the transcription of genes which encode glucose transporters and enzymes involved in glycolysis. Recent reports suggest that several non-hypoxic stimuli such as lipopolysaccharides, thrombin, and angiotensin II can also increase HIF-1α under normoxia. Herein, we investigated the effects of MUC13 expression on glucose metabolism and elucidated underlying signaling mechanisms that might be involved in this process. Methods: MUC13 null pancreatic cancer Panc-1 cells were used for the study. Glucose and Lactate assay were performed in Panc-1 cells stably expressing MUC13 (Panc-1-M13) and vector (Panc-1-V). Cell culture media after 48 hrs was collected to measure the amount of unused glucose and L-lactate concentration using glucose and Lactate assay kits. Immunoblot and semi-quantitative PCR analyses were performed to check the expression of protein and mRNA levels, respectively. Cell proliferation and colony forming assays were performed to determine the effect of MUC13 on cellular growth and cell survival. Results: Our results demonstrate that MUC13 acts as a modulator of the glucose metabolism in pancreatic cancer cells by regulating the expression and activity of hypoxia-inducible factor-1α (HIF-1α) and its downstream targets. We observed increased amount of L-lactate production and glucose consumption in Panc-1-M13 cells as compared to Panc-1-V cells. This facilitates metabolic alterations and help tumor cells survive and proliferate under these conditions as indicated by increased cellular growth pattern in Panc-1-M13 cells. Our results demonstrate increased expression of the downstream targets of HIF-1α, such as cell regulatory (c-Myc), and cell survival (Bcl-2) proteins, while decreased the expression of tumor suppressor/cell cycle inhibitor (p-27) proteins in Panc-1M13 cells. Additionally, an increase in the expression of a critical downstream target of HIF-1α, Glut-1 was observed in Panc-1-M13 cells. Conclusion: Our studies indicate that MUC13 acts as a key regulator of the metabolic process and facilitates metabolic alterations in the non-hypoxic environment that help tumor cells survive and proliferate under these conditions. However, further studies are required to elucidate detailed molecular mechanisms that are involved in MUC13 mediated metabolic remodeling in pancreatic cancer cells. Citation Format: Sonam Kumari, Sheema Khan, Subhash Chauhan, Meena Jaggi. Role of MUC13 as non-hypoxic stimuli inducing HIF-1α in pancreatic cancer under normoxia. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 51.

Simplified strong ion difference approach to acid-base balance in healthy foals.

To determine the strong ion difference (SIDa ) and total nonvolatile weak buffers (ATOT ) in healthy foals during the first year of life and to compare reference biochemistry laboratory with analyzers available during emergency hours. Prospective study performed over 2 years. University teaching hospital. Two hundred thirty-six healthy foals distributed in 6 groups: A (21 days-2 months), B (2-3 months), C (3-6 months), D (6-9 months), E (9-12 months), and 33 neonatal foals (< 21 days old). Blood samples were obtained to determine L-lactate, sodium, potassium, chloride, and total plasma protein concentrations. In neonatal foals, samples were analyzed using 4 different devices. Reference intervals of SIDa and ATOT for each of the analyzers under comparison were established using mean ± 2 standard deviations. Age effect was evaluated using one-way ANOVA analysis. Linear regression in neonatal foals was employed to obtain a new equation to estimate ATOT from total plasma protein concentration. A significant age effect was observed for ATOT and SIDa . In all foals younger than 6 months, ATOT values were lower than in older foals (P < 0.003). A clinically and statistically significant difference in SIDa was detected only in the neonatal period (P < 0.001). The equation to estimate ATOT from total plasma protein adjusted for neonatal foals is ATOT = 2.5 × total plasma protein concentration. Reference intervals of ATOT should be considered different from adults during the first 6 months of life in horses. Regarding SIDa , values should be considered different only during first 21 days of life.

Plasmatic L-lactate in pet rabbits: association with morbidity and mortality at 14 days.

The clinical relevance of plasmatic L-lactate concentration (PLLC) is unknown in rabbits. Due to an entirely different metabolism of lactic acid, PLLC in rabbits can reach much higher concentrations than in other species. The aim of this study was to establish a reference interval (95% RI) for venous PLLC in pet rabbits and to assess its diagnostic and prognostic significance in ill pet rabbits. Plasmatic L-lactate concentration was determined by an enzymatic colorimetric method. In the first study, healthy rabbits (n = 140) were the control group. The ill rabbits group (n = 405) included the deceased (n = 108) and the survivors (n = 266), depending on the outcome at day 14. In a second study, variation in the PLLC was determined in 25 boarding (control-serial), 99 hospitalized (deceased-serial [n = 27], and survivors-serial [n = 72]) rabbits sampled at 0, 12, 24 and 48 hours. The 95% RI for PLLC in controls was 2.1-15.2 mmol/L. On-arrival PLLC in ill rabbits was not statistically different from those in the control group, but was significantly lower in deceased compared to survivors or controls. The range of PLLC variation differed significantly between control-serial, deceased-serial, and survivors-serial groups. A better prognosis was associated with an increase of 3.3 mmol/L PLLC within 48 hours after arrival. Contrary to the available information in other species, morbidity and mortality is associated with sustained low PLLC in pet rabbits, while a good prognosis is associated with an increase in PLLC. Monitoring PLLC in hospitalized rabbits is advisable.

Fermentation Characteristics along the Gastrointestinal Tract after Feeding of Jerusalem Artichoke Meal to Adult Healthy Warmblood Horses

Objective: Prebiotics are used to support the gastrointestinal health via stimulating particular beneficial parts of the autochthonous microflora and enhancing their metabolism.Horses often suffer from gastrointestinal disturbances after feed changes or behavioral stress in response to transport. Therefore, the supplementation with prebiotic compounds might reduce the risk for intestinal dysregulation. The aim of this study was to investigate the influence of supplementation with Jerusalem artichoke meal (JAM) in a recommended prebiotic dosage on fermentation characteristics in the equine gastrointestinal tract. Methods: Twelve adult healthy horses received crushed oat grains (1.2 g starch/kg BW x d-1) and meadow hay (as fed basis; 1.5 kg/100 kg BW x d-1). Additionally, they were fed either an apparently prebiotic quantity of fructooligosaccharides (FOS) and inulin (0.2 g/kg BW x d-1) via Jerusalem artichoke meal (JAM) or an equal amount of maize cob meal without grains as control (CON) over 3 weeks. On d21, horses were euthanized, gastrointestinal contents were removed from 7 different regions of the gastrointestinal tract, the dry matter (DM) content, pH value and concentrations of short chain fatty acids (SCFA), L- and D-lactate and ammonia were measured. Results: JAM did not had a significant (P 0.05), lactate (both isomers, P > 0.05) and ammonia (P 0.05) and ammonia (P > 0.05) but lower L-lactate (P > 0.05) concentrations compared to control.

Acid base imbalances in ill neonatal foals and their association with survival.

Acid-base imbalances observed in human paediatric patients are associated with outcome. Likewise, neonatal foals may have different acid-base imbalances associated with diagnosis or prognosis. To determine acid-base imbalances by the quantitative method in ill neonatal foals and assess their association with diagnosis and prognosis. Observational prospective clinical study. This study included 65 ill neonatal foals (32 septic, 33 nonseptic) admitted to an equine referral hospital from 2005 to 2011with acid-base parameters determined on admission and a control group of 33 healthy neonatal foals. Blood pH, pCO2 , sodium, potassium, chloride, L-lactate, albumin and phosphate concentrations were determined. Bicarbonate, globulin, measured strong ion difference (SIDm ), nonvolatile weak buffer concentrations (Atot ), base excess and its components were calculated. Analysis of covariance (ANCOVA) and multiple linear regression statistical analyses were performed. Results are summarised as mean ± s.d. for normally distributed variables and median [25-75th percentiles] for non-normally distributed ones. A total of 63% of ill foals had respiratory alkalosis and 58.5% had SIDm acidosis. The combination of both alterations was detected in 21 of 65 ill foals and abnormal pH was found in 24 of 65. Compared with healthy foals, ill foals had significantly lower SIDm (nonseptic 31.6 ± 6.3 [P<0.01] and septic 32.0 ± 6.4 [P<0.01] vs. control 40.3 ± 3.1 mmol/l), potassium (nonseptic 3.5 [3.3-3.8; P<0.01] and septic 3.6 [3.2-4.3; P = 0.01] vs. control 4.2 [3.8-4.5] mEq/l) and higher L-lactate (nonseptic 5.1 ± 4.2 [P = 0.01] and septic 5.0 ± 3.7 [P = 0.03] vs. control 2.5 ± 1.3 mmol/l). Significantly higher L-lactate and venous pCO2 were found in nonsurviving (6.4 ± 3.5 mmol/l [P = 0.04] and 51 ± 13 mmHg [P<0.01]) compared with surviving foals. The most common acid-base imbalances observed in ill foals were respiratory alkalosis, SIDm acidosis or mixed respiratory alkalosis with strong ion acidosis. Increased venous pCO2 and blood L-lactate concentration were associated with poor outcome.

Reduction of d-lactate content in sauerkraut using starter cultures of recombinant Leuconostoc mesenteroides expressing the ldhL gene

The D-form of lactate, which causes metabolic stress upon excessive dietary intake, is mainly produced by Leuconostoc sp., the predominant species in sauerkraut. To shift the metabolic flux of d-lactate from pyruvate to l-lactate, we expressed the l-lactate dehydrogenase (ldhL) gene in Leuconostoc mesenteroides ATCC 8293. The ldhL gene from Lactobacillus plantarum was introduced into L. mesenteroides using the shuttle vectors pLeuCM and pLeuCM42. To elevate the expression level of ldhL in L. mesenteroides, the nucleotides for pyruvate kinase promoter were fused to ldhL and cloned into above vectors to construct pLC18pkL and pLC42pkL. As results, introduction of pLC42pkL in L. mesenteroides significantly improved both l-LDH activity and l-lactate productivity during fermentation, decreasing the d-/l-lactate ratio. When used as a starter culture for sauerkraut fermentation, recombinant L. mesenteroides harboring pLC42pkL increased l-lactate concentration and decreased d-lactate concentration compared to the wild type strain. We newly developed a recombinant L. mesenteroides which has high l-lactate dehydrogenase activity and applied this strain to minimize the harmful effect of d-lactate during the sauerkraut fermentation. To the best of our knowledge, we demonstrate for the first time the effective use of recombinant Leuconostoc sp. for quality improvement of fermented foods.

Avaliação hemogasométrica, bioquímica e hematológica de ovinos suplementados com melão

RESUMOO presente trabalho avaliou os efeitos da administração de duas diferentes quantidades de melão sobre variáveis hemogasométricas, bioquímicas e hematológicas de ovinos não adaptados. Foram utilizados 12 ovinos canulados, pesando 25kg de peso vivo, que nunca receberam ração concentrada. Os animais receberam dieta à base de feno (2,3% do peso vivo) e água à vontade. Os ovinos foram distribuídos aleatoriamente em dois grupos e receberam 25% ou 75% da matéria seca (MS) da dieta de melão triturado (G25% e G75%, respectivamente) diretamente no rúmen. Foram realizadas coletas de sangue e determinação do pH ruminal nos seguintes tempos: zero, 3, 6, 12, 18 e 24 horas após oferecimento do melão. Foi realizada análise hemogasométrica, do volume globular, determinação da concentração plasmática de lactato-L, glicose e osmolaridade sérica. No G25%, o pH sanguíneo variou entre 7,40 e 7,31, enquanto o G75% apresentou pH entre 7,38 e 7,26. Maiores concentrações de glicose plasmática foram detectadas no G75% no T3, T6 e T12 (P&lt;0,05). Os ovinos que receberam 25% de melão mantiveram parâmetros sanguíneos dentro da normalidade, ao passo que, no G75%, os ovinos apresentaram discreta acidose metabólica sistêmica e hiperglicemia. A suplementação com 25% de melão pode ser uma alternativa segura na alimentação de ovinos.

Reliability of the Lactate Scout point-of-care instrument for the determination of blood L-lactate concentration in sheep.

Data on accuracy and precision of the Lactate Scout point-of-care (POC) analyzer in ovine medicine are lacking. The purpose of the study was to assess the reliability of the Lactate Scout in sheep. Fifty-seven sheep at varying ages with various diseases were included. Blood lactate concentration in samples collected from the jugular vein was measured immediately on the Lactate Scout. Plasma L-lactate concentration was measured by the Cobas autoanalyzer as the reference method. Data were subjected to Student's t-test, Passing-Bablok regression, and Bland-Altman plot analyses for comparison and assessment of accuracy, precision, and reliability. Plasma l-lactate concentration was consistently lower than blood L-lactate concentration (3.06 ± 0.24 vs 3.3 ± 0.3 mmol/L, P < .0001). There was a positive correlation between plasma and blood L-lactate concentrations (r = .98, P < .0001). The Lactate Scout had 99% accuracy and 98% precision with the reference method. Blood (Y) and plasma (X) L-lactate concentrations were fitted to Y = 0.28 + 1.00 · X, with a residual standard deviation of 0.31 and a negligible deviation from the identity line (P = .93). The bias was fitted to Y = 0.10 + 0.05 · X, with Sy.x of 0.44 (P < .07). The Lactate Scout has high accuracy and precision, with a negligible bias. It is a reliable POC analyzer to assess L-lactate concentration in ovine medicine.

Abstract 1427: Embigin is overexpressed in pancreatic ductal adenocarcinoma and regulates cell motility through epithelial to mesenchymal transition via the TGF-β pathway

Abstract Embigin is a member of the immunoglobulin superfamily and encodes a transmembrane glycoprotein. Strong expression of Embigin has been observed in the mouse endoderm during early postimplantation embryogenesis and in the gut and visceral endoderm at the somite stage. There have been reports of Embigin involvement in neuromuscular junction formation and plasticity; however, the molecular functions of Embigin in other organs are unknown. Pancreatic cancer is an extremely aggressive malignancy, and it is necessary to understand the biology of pancreatic cancer to better detect and treat this disease. Our aim was to investigate the possible role of Embigin in pancreatic cancer. In pancreatic ductal adenocarcinoma tissues, Embigin expression was higher than that in normal pancreatic tissues. Immunohistochemical analysis revealed expression of Embigin in pancreatic cancer cells, as well as expression of monocarboxylate transporter 2 (MCT2) in cancer tissues. To gain further insight, we transfected BxPC-3 and HPAC pancreatic cancer cells with siRNA or shRNA targeting Embigin and observed reductions in cell proliferation, migration, invasion, wound healing, and reduced levels of matrix metalloproteinases-2 and -9. Silencing of Embigin increased intracellular L-lactate concentration by 1.5-fold and decreased MCT2 levels at the plasma membrane. Furthermore, Embigin silencing led to a reduced expression of PI3K, GSK3-β, and Snail/Slug. Upon treating BxPC-3 cells with transforming growth factor-β (TGF-β), we observed elevated expression of Snail/Slug, Embigin, and Vimentin; meanwhile, when treating cells with SB-216763, a GSK3-β inhibitor, we noted decreases in GSK3-β, Snail/Slug, and Embigin expression, suggesting that the TGF-β signaling cascade, comprising PI3K, GSK3-β, Snail/Slug, and Embigin signals, mediates epithelial to mesenchymal transition (EMT) in pancreatic cancer cells. These findings indicate the involvement of Embigin in EMT in pancreatic cancer progression and suggest Embigin as a putative target for the detection and/or treatment of pancreatic cancer. Citation Format: Dawoon E. Jung, Jeong Mi Kim, Chanyang Kim, Si Young Song. Embigin is overexpressed in pancreatic ductal adenocarcinoma and regulates cell motility through epithelial to mesenchymal transition via the TGF-β pathway. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 1427. doi:10.1158/1538-7445.AM2015-1427

Is L-lactate a novel signaling molecule in the brain?

In the brain, L-lactate is produced by both neurons and astrocytes. There is no doubt that neurons use L-lactate as a supplementary fuel although the importance of this energy source is disputed. Irrespective of its caloric value, L-lactate might also have a signaling role in the brain. Here, we review several current hypotheses of L-lactate mediated signaling. Some proposed mechanisms require L-lactate entry into the neurons leading to a shift in ATP/ADP ratio or redox state. Others postulate interaction with either known receptor HCA1 (GPR81) or a novel, yet unidentified receptor. We argue that the sensitivity of any such mechanism has to match the concentration range of extracellular L-lactate, which is less than ~1.5 mmol/L under physiologic conditions. From that point of view, some of the proposed mechanisms require supraphysiologic levels of L-lactate and could be engaged during ischemia or seizures when L-lactate concentration rises dramatically. Currently, we do not know whether L-lactate production in the brain occurs in microdomains, which might create higher than average local concentrations. Nevertheless, it is clear that in the brain, as in the peripheral tissues, L-lactate is not only used as a source of energy but also acts as a signaling molecule.

Serum biochemistry reference intervals of live wild dugongs (Dugong dugon) from urban coastal Australia.

Little is known about the baseline clinical pathology of the dugong (Dugong dugon), a vulnerable marine mammal found in tropical coastal marine systems. The purpose of the study was to collect and determine reference intervals (RI) for select serum biochemical variables for dugongs, and to analyze differences between males and females and different age groups. Reference intervals were established from 103 apparently healthy, wild-caught dugongs for 31 analytes using a Beckman Coulter AU400 Automated Chemistry Analyzer and an Olympus AU680 Chemistry-Immuno Analyzer. Significant differences (P<.05) in some of the variables were found related to size class, sex, and pregnancy status. Adult dugongs had higher serum sodium, potassium, bicarbonate, glucose, and l-lactate concentrations and higher anion gap, compared to sub-adults. Male dugongs had higher triglyceride and l-lactate concentrations than females. Pregnant females displayed higher l-lactate levels compared to nonpregnant animals. Statistical differences in variables within the population contributed to better understanding of the physiologic differences between cohorts. Some serum biochemistry changes observed in this study here also potentially include some effects of pursuit on dugongs (eg, higher l-lactate); however, as all dugongs were subject to similar capture and handling, serum biochemistry RI should be considered as normal for captured dugongs. The serum biochemical RI documented here are considered representative of a population of healthy captured dugongs. They provide a baseline for health surveillance of this and other dugong populations.

Evaluation of Some Physical, Haemathological and Clinical Chemistry Parameters in Healthy Newborn Italian Holstein Calves

The aim of the present study was to investigate some physical, haematological and clinical chemistry parameters in the newborn Italian Holstein calf at birth and at 24 h of life, to evaluate changes during the immediate post-partum period. Forty-six Italian Holstein Friesian calves were included in this study. Heart rate, respiratory rate and body temperature were recorded at birth and at 24 h of life. The time needed to raise the head, acquire sternal recumbency, stand up were also recorded. Blood samples were collected before first feeding and at 24 h of age and CBC count, L-lactate, glucose and total protein concentrations were evaluated. The head was raised immediately in 46/46 calves, suckling reflex was acquired within 12±9 min, sternal position in 5±2 min and newborn stood up in 38±30 min. Some of the physical data, haematological and biochemical values showed statistical differences between birth and 24 h of age. The results from this study provide some information about physical and laboratory data of Italian Holstein Friesian calves, at birth and at 24 h of life. Our results confirm that several clinical and laboratory values in newborn calves differ from adult reference intervals and from calves of different breeds.

Embigin is overexpressed in pancreatic ductal adenocarcinoma and regulates cell motility through epithelial to mesenchymal transition via the TGF-β pathway.

Embigin is a member of the immunoglobulin superfamily and encodes a transmembrane glycoprotein. There have been reports of Embigin involvement in neuromuscular junction formation and plasticity; however, the molecular functions of Embigin in other organs are unknown. Our aim was to investigate the possible role of Embigin in pancreatic cancer. In pancreatic ductal adenocarcinoma tissues, Embigin expression was higher than that in normal pancreatic tissues. Immunohistochemical analysis revealed expression of Embigin in pancreatic cancer cells, as well as expression of monocarboxylate transporter 2 (MCT2) in cancer tissues. To gain further insight, we transfected BxPC-3 and HPAC pancreatic cancer cells with siRNA or shRNA targeting Embigin and observed reductions in cell proliferation, migration, invasion, wound healing, and reduced levels of matrix metalloproteinases-2 and -9. Silencing of Embigin increased intracellular L-lactate concentration by 1.5-fold and decreased MCT2 levels at the plasma membrane. Furthermore, Embigin silencing led to a reduced expression of PI3K, GSK3-β, and Snail/Slug. Upon treating BxPC-3 cells with transforming growth factor-β (TGF-β), we observed elevated expression of Snail/Slug, Embigin, and Vimentin; meanwhile, when treating cells with SB-216763, a GSK3-β inhibitor, we noted decreases in GSK3-β, Snail/Slug, and Embigin expression, suggesting that the TGF-β signaling cascade, comprising PI3K, GSK3-β, Snail/Slug, and Embigin signals, mediates epithelial to mesenchymal transition (EMT) in pancreatic cancer cells. These findings indicate the involvement of Embigin in EMT in pancreatic cancer progression and suggest Embigin as a putative target for the detection and/or treatment of pancreatic cancer.

Preliminary investigation of the area under the L-lactate concentration-time curve (LACArea) in critically ill equine neonates.

BackgroundA variety of measures of l‐lactate concentration ([LAC]) in the blood of critically ill neonatal foals have shown utility as prognostic indicators. These measures, evaluating either the severity of hyperlactatemia or the duration of exposure to hyperlactatemia, perform fairly well and have correctly classified 75–80% of foals examined in several studies. The area under the l‐lactate concentration versus time curve (LAC Area) encompasses both severity and duration of hyperlactatemia and should improve correct classification of patient survival.Hypothesis/Objectives LAC Area is larger in nonsurviving critically ill neonatal foals.AnimalsForty‐nine foals admitted for critical illness to 1 of 4 referral hospitals.MethodsWhole blood was obtained at admission and 6, 12, 18, and 24 hours after admission for measurement of l‐lactate using a handheld lactate meter. LAC Area was calculated for: admission–6, 6–12, 12–18, 18–24 hours, and admission–24 hours using the trapezoidal method and summing the 6‐hours interval areas to determine total 24 hours area. Differences between survivors and nonsurvivors were determined using robust regression and Kruskal–Wallis testing, P < .05.Results LAC Area was significantly larger in nonsurviving foals (n = 9) than in surviving foals (n = 40) at all time periods examined.Conclusions and Clinical ImportanceDifferences in LAC Area between surviving and nonsurviving critically ill neonatal foals are large and support further investigation of this method as an improved biomarker for survival in critically ill neonatal foals is indicated.

Association of aldosterone and arginine vasopressin concentrations and clinical markers of hypoperfusion in neonatal foals.

Critically ill foals often present to veterinary hospitals with impaired organ perfusion which can be demonstrated by increased blood L-lactate concentrations. As a compensatory mechanism to low blood pressure and electrolyte abnormalities, aldosterone and arginine vasopressin (AVP) are released to restore organ perfusion and function. Several studies have investigated the ability of blood L-lactate concentrations to predict severity of disease and outcome in critically ill human patients, adult horses and foals. However, information on the aldosterone and AVP response to hypoperfusion and its association with L-lactate concentrations in neonatal foals is limited. To determine the association between clinical hypoperfusion and endocrine markers of reduced tissue perfusion in normo- and hypoperfused foals. Prospective, multicentre, cross-sectional observational study. Blood samples were collected on admission from 72 clinically hypoperfused, 110 normoperfused (73 hospitalised and 37 healthy) foals of ≤4 days of age. Foals were considered clinically hypoperfused if they had L-lactate concentrations ≥2.5 mmol/l and one of the 3 following findings: heart rate >120 beats/min, packed cell volume (PCV) >0.44 l/l or azotaemia (increased creatinine and blood urea nitrogen [BUN]). Blood concentrations of aldosterone and AVP were determined by radioimmunoassays. Aldosterone, AVP, creatinine and BUN concentrations and heart rate, PCV and blood osmolality were higher in clinically hypoperfused compared with normoperfused foals (P<0.05). Risk of hypoperfusion increased with the presence of hypothermic extremities (OR = 5.26) and with each one unit increase in albumin concentrations (OR = 3.5) (P<0.05). The proposed admission L-lactate cut-off value above which nonsurvival could be reliably predicted in hospitalised foals was 10.6 mmol/l with 82% of sensitivity and 74% of specificity. Hyperaldosteronaemia and hypervasopressinaemia as well as hypothermic extremities and increased albumin concentrations are potent predictors of hypoperfusion in hospitalised foals.

Role of Monocarboxylate Transporter in Statin-induced Cytotoxicity

Although exercise and drug therapy are important to prevent progression of arteriosclerotic disease, exercise leads to an increase in muscular disorder induced by HMG-CoA reductase inhibitors (statins). Elucidation of this mechanism is needed to prevent the occurrence of muscular disorders. Since exercise induces expression of monocarboxylate transporter (MCT) 4, we focused on the association between MCT4 function and statin-induced muscle injury. First, we examined the transport of L-lactate via MCT4 using MCT4 cRNA-injected Xenopus laevis oocytes. L-lactate uptake by MCT4-expressing oocytes was markedly reduced by alkalizing the buffer pH and saturated at higher L-lactate concentrations. On the other hand, AMP-activated protein kinase (AMPK) and protein kinase C (PKC) are activated by exercise. We next examined whether AMPK and PKC activation affects the expression and function of MCT4 in rat skeletal muscle and RD cells as an in vitro skeletal muscle model. AMPK and PKC activation increased MCT4 expression level and lactate efflux by MCT4. Finally, we examined the association between MCT4 function and statin-induced cytotoxicity. Statins inhibited transport of L-lactate via MCT4 in a concentration-dependent manner. Statin-induced cytotoxicity was associated with intracellular acidification and caspase-3/7 activation. On the other hand, bicarbonate suppressed statin-induced pH alteration, caspase activation, and morphological change. The results suggest that statin-induced muscle injury exacerbated by exercise is associated with intracellular acidification and that the effects of statins on L-lactate transport are mediated by MCT4.

D-lactate is a valid biomarker of intestinal ischemia induced by abdominal compartment syndrome

BackgroundIntra-abdominal hypertension (IAH) often leads to abdominal compartment syndrome, which is followed by intestinal ischemia and associated with a high mortality. The diagnosis of abdominal compartment syndrome is difficult, and no valid biochemical markers are available. We conducted an experimental study on pigs to determine if D-lactate could be a useful biochemical marker of intestinal ischemia. Materials and methodsA total of eight pigs (intervention group) underwent insufflation of carbon dioxide in the abdominal cavity to induce IAH and were compared with that of eight pigs (sham group) without IAH. Blood samples were taken from the portal and jugular veins at 0, 60, 120, 180, and 240 min after insufflation of carbon dioxide, and concentrations of D-lactate and L-lactate in the two groups were compared using an unpaired t-test. ResultsThe concentrations of D-lactate were increased in portal blood after 180 min of IAH (P = 0.036) and jugular blood after 240 min of IAH (P = 0.028) in the intervention group compared with those in the sham group. A similar tendency was found for L-lactate levels after 180 min of IAH (P = 0.032 and P = 0.017 for portal and jugular blood samples, respectively). Examination of the intestines revealed both macroscopic and microscopic signs of ischemia in all but one animal in the intervention group and only in one sham-pig. ConclusionsOur findings suggest that D-lactate could be a useful biochemical marker of intestinal ischemia induced by IAH.

Cardiac arrhythmias and electrolyte disturbances in colic horses.

BackgroundDespite increased focus on cardiac arrhythmias in horses, the nature and prevalence is still poorly described. Case reports suggest that arrhythmias occurring secondary to systemic disease are seen more commonly in the clinic than arrhythmias caused by cardiac disease. The aim of this study was to investigate the prevalence of arrhythmias in colic horses referred for hospital treatment. Associations between electrolyte disturbances and arrhythmias were also investigated.The study population consisted of eight control horses and 22 referred colic horses. A Holter electrocardiography (ECG) was recorded during the first 24 hours of admission. The ECG’s were analysed by a software program followed by manual visual inspection. Arrhythmias registered included second degree atrioventricular (AV) blocks, supraventricular premature complexes (SVPCs), and ventricular premature complexes (VPCs). Blood was collected at admission and again between 12 and 24 hours after ECG was applied, and analysed for concentrations of potassium, sodium, ionised calcium, chloride, glucose, and L-lactate.ResultsHeart rate was 37.4 ± 3.7 bpm in the control group, and 51.6 ± 11.8 bpm, in the colic group, which was significantly different (P < 0.0001). AV blocks and SVPCs were found in both groups, however only colic horses showed VPCs. No significant difference between the two groups was found for AV blocks, SVPCs, and VPCs (P = 0.08 - 0.76). The mean levels of potassium, sodium, ionized calcium, and chloride were significantly lower in the colic group compared to the control group at admission. Mean levels of glucose and L-lactate were significantly elevated in the colic group (P < 0.05).ConclusionsThis study describes prevalence of cardiac arrhythmias and electrolytes concentrations in colic horses compared to healthy controls. Although we only observed VPCs in the colic horses, no significant differences between colic horses and controls were found. Despite the colic horses having electrolyte changes at admission no correlation was found between the electrolyte disturbances and cardiac arrhythmias. Although no clear conclusions can be drawn from the present study, the results indicate that relatively mild colic per se is not pro-arrhythmogenic, whereas severe colic probably are more likely to result in ventricular arrhythmia.

Validation of the handheld Lactate-Pro analyzer for measurement of blood L-lactate concentration in cattle.

Blood L-lactate concentration (LAC) can be used for various diagnostic purposes in cattle. As multiple handheld analyzers for LAC exist, it is important to validate their use in cattle in comparison with reference laboratory blood analyzers. The objectives of this study were to validate the handheld Lactate Pro meter (LacP) including reproducibility, and compare the measurements with the StatProfile (StatP) as a gold standard. In addition, diagnostic sensitivity and specificity, and the impact of HCT on LAC measured by both analyzers were assessed. A cohort of 64 cattle with acute medical and surgical conditions was studied. Whole blood samples in heparin lithium tubes were analyzed upon arrival with both StatP and LacP. Twenty-three samples were immediately retested to assess intra-assay coefficient of variation (CV). The HCT values were also recorded. The LAC using LacP was highly correlated with the StatP (r=0.9736 [95% confidence interval [CI]: 0.9562-0.9841]). The LacP underestimated LAC (mean difference:-0.9mmol/L, 95% CI:-3.1mmol/L to 1.3mmol/L). The intra-assay CV was excellent (4.77%). No significant correlation was observed between LacP or StatP and HCT (P=.39 and .09, respectively). Sensitivity and specificity for LacP were 91.7% (95% CI: 76.4-97.8%) and 100% (83.4-100%, cutoff of 4mmol/L), and 78.6% (58.5-90.9%) and 100% (87.0-100%, cutoff of 6mmol/L). The LacP handheld lactate meter can be used safely and reliably cow-side, although it underestimates LAC value when compared with a standard laboratory analyzer especially for LAC≥10.0mmol/L. The LAC value was not influenced by HCT in this study.

Online electrochemical method for continuous and simultaneous monitoring of glucose and l-lactate in vivo with graphene hybrids as the electrocatalyst

This study described a physiologically relevant on-line electrochemical method for simultaneous monitoring of glucose and l-lactate in vivo with good sensitivity and selectivity. The analytical system that constructed by dual-enzyme biosensor was based on a novel and effective graphene hybrids with the on-line microdialysis system, which made the continuous and simultaneous monitoring of striatum glucose and l-lactate in brain of freely moving rats possible. The dual-enzyme biosensor was accomplished by using oxidases as the specific sensing unit and the UV-assisted synthesized Graphene/ZnO@Pd as the electrocatalyst. Transmission electron microscopy, X-ray diffraction, energy-dispersive X-ray and X-ray photoelectron spectroscopy confirmed the denoted Pd nanoparticles (NPs) on the Graphene/ZnO composites. The analytical system showed good linearity for glucose and l-lactate concentrations from 20μM to 500μM with detection limit of 2.39μM and 2.52μM respectively. After post-calibration, the basal level concentrations of glucose and l-lactate in the microdialysate from the striatum of freely moving rats were calculated to be 0.323±0.021mM and 0.501mM±0.057mM (mean±s.d., n=3). Moreover, the dual oxidase/Graphene/ZnO@Pd based biosensors suffered from little cross-talk and exhibit a good stability and reproducibility.