Increase In Plasma Lactate Concentration Research Articles

Maternal Dietary Carbohydrate Restriction and Mild-to-Moderate Exercise during Pregnancy Modify Aspects of Fetal Development in Rats

To determine whether acute bouts of exercise during pregnancy would predispose the fetus to increased risk if maternal dietary carbohydrate were restricted, untrained pregnant rats were randomly assigned to a 0% (low), 12% (moderate) or 60% (high) glucose diet, and either rested or exercised daily for 20 min from d 16 to term on a rodent treadmill at a mild (15.5 m/min) or moderate (24.3 m/min) intensity. A 3 ՠ3 nested factorial model with and without food intake as a covariate was employed. Both greater exercise intensity and the lower levels of dietary carbohydrate independently decreased term maternal liver and plantaris glycogen concentrations and increased plasma lactate concentrations. However, significant differences due to exercise disappeared (except for plasma lactate) with food intake controlled for in the model, indicating that energy deficits modulated these exercise effects. In contrast, for the offspring, when food intake was controlled for, a restricted level of maternal dietary carbohydrate significantly lowered fetal weight, plasma glucose and insulin concentrations and liver glycogen concentrations measured at term. Exercise alone did not reduce mean fetal weight if nested weights within a litter were used in the statistical analysis. Mild to moderate maternal exercise lowered only fetal plasma glucose concentrations and only if maternal food intake was not controlled for. These results indicate that acute exercise during pregnancy can have detrimental effects on fetal development only if dietary glucose is severely restricted. Otherwise, adequate glucose and energy in the maternal diet in untrained pregnant rats during repeated bouts of acute exercise seem to protect the fetus.

Caffeine Combined With Sodium Bicarbonate Improves Pacing and Overall Performance During a High-Intensity Time Trial

ABSTRACT Background: No study has demonstrated the effects of sodium bicarbonate plus caffeine (NaHCO3 + CAF) on power output (PO) distribution (e.g., pacing), physiological parameters and energy system contribution during a 4-km cycling time trial (TT). Thus, we aimed to investigate the effects of NaHCO3 + CAF on pacing, physiological parameters, and energy system contribution during a 4-km cycling TT.Methods: Using a double-blind and counterbalanced design, 10 cyclists performed three ingestion protocols (NaHCO3 + CAF, NaHCO3 and placebo) followed by a 4-km cycling TT.Results: 100 min after substance ingestion, the magnitude of change in blood pH and bicarbonate concentration [HCO3 –] for NaHCO3 + CAF (+0.04 ± 0.03 and +5.9 ± 1.6 mmol·L−1, respectively, P < .05) and NaHCO3 (+0.02 ± 0.03 and +4.1 ± 2.0 mmol·L−1, respectively, P < .05) was more pronounced than in placebo (−0.01 ± 0.02 and 0.4 ± 0.9 mmol·L−1, respectively). The increase in plasma lactate concentration was more pronounced in NaHCO3 + CAF than in NaHCO3 and placebo (P < .05). Mean ventilation and carbon dioxide production were higher in NaHCO3 + CAF compared to NaHCO3 and placebo (P < .05). The PO and anaerobic power output were increased at the beginning of the 4-km TT (P < .05) in NaHCO3 + CAF compared to the other two conditions, resulting in an improved overall performance (P < .05).Conclusion: NaHCO3 + CAF results in a higher PO and increased anaerobic contribution and respiratory parameters during a 4-km cycling TT.

Comparison of the Effects of 6 Weeks of Traditional and Wrestling-Technique-Based Circuit Training on the Blood Levels of Lactate, Lactate Dehydrogenase, Glucose, and Insulin in Young Male Wrestlers

Background: Nowadays, circular training has become more common than traditional training in wrestling. Objectives: This study aimed to compare the effects of 6 weeks of traditional and circular wrestling training on blood lactate, lactate dehydrogenase (LDH), glucose, and insulin concentrations in young male wrestlers. Methods: Twenty-seven young male wrestlers were randomly divided into 3 groups (ie, traditional wrestling training, circular wrestling training, and control groups) and performed interventions based on the group name for 6 weeks. Blood samples were taken from all subjects 48 hours before and 48 hours after the interventions and sent to a laboratory for analysis. Blood concentrations of lactate, LDH, glucose, and insulin were measured by enzyme-linked immunosorbent assay (ELISA). Data were analyzed using multivariate analysis of covariance (MANCOVA) and suitable post hoc test. Results: Traditional training significantly increased plasma lactate concentrations of wrestlers (P = 0.01) and had no significant effect on their serum LDH, insulin, and glucose concentrations (P &gt; 0.05). Circular training significantly increased plasma lactate (P = 0.03) and serum insulin (P = 0.004) concentrations and had no significant effect on serum LDH and glucose concentrations (P &gt; 0.05). Conclusions: These 2 types of training have a similar effect on the measured variables; however, it seems that circular training has a more significant effect on the measured variables than traditional training, which can probably be attributed to the use of more lactic energy resources and apparatus in circular training, which in turn can be used in preparation.

Strenuous swimming raises blood non-enzymatic antioxidant capacity in rats.

The non-enzymatic antioxidant system protects blood components from oxidative damage and/or injury. Herein, plasma non-enzymatic antioxidant capacity after acute strenuous swimming exercise (Exe) and exercise until exhaustion (Exh) was measured in rats. The experiments were carried out in never exposed (Nex) and pre-exposed (Pex) groups. The Nex group did not undergo any previous training before the acute strenuous swimming test and the Pex group was submitted to daily swimming for 10 min in the first week and 15 min per day in the second week before testing. Plasma glucose, lactate, and pyruvate were measured and plasma total protein sulfhydryl groups (thiol), trolox equivalent antioxidant capacity (TEAC), ferric reducing ability of plasma (FRAP), and total radical-trapping antioxidant parameter (TRAP) levels were evaluated. There were marked increases in plasma lactate concentrations (Nex-Control 1.31±0.20 vs NexExe 4.16±0.39 vs NexExh 7.19±0.67) and in thiol (Nex-Control 271.9±5.6 vs NexExh 314.7±5.7), TEAC (Nex-Control 786.4±60.2 vs NexExh 1027.7±58.2), FRAP (Nex-Control 309.2±17.7 vs NexExh 413.4±24.3), and TRAP (Nex-Control 0.50±0.15 vs NexExh 2.6±0.32) levels after acute swimming and/or exhaustion. Also, there were increased plasma lactate concentrations (Pex-Control 1.39±0.15 vs PexExe 5.22±0.91 vs PexExh 10.07±0.49), thiol (Pex-Control 252.9±8.2 vs PexExh 284.6±6.7), FRAP (Pex-Control 296.5±15.4 vs PexExh 445.7±45.6), and TRAP (Pex-Control 1.8±0.1 vs PexExh 4.6±0.2) levels after acute swimming and/or exhaustion. Lactate showed the highest percent of elevation in the Nex and Pex groups. In conclusion, plasma lactate may contribute to plasma antioxidant defenses, and the TRAP assay is the most sensitive assay for assessing plasma non-antioxidant capacity after strenuous exercise.

Intraoperative increased plasma lactate concentration as a prognostic factor for liver transplant recipients: a retrospective cohort study

Intraoperative increased plasma lactate concentration as a prognostic factor for liver transplant recipients: a retrospective cohort study

Plasma BCAA concentrations during exercise of varied intensities in young healthy men-the impact of endurance training.

BackgroundBranched-chain amino acids (BCAA) i.e., leucine (Leu), isoleucine (Ile) and valine (Val) are important amino acids, which metabolism play a role in maintaining system energy homeostasis at rest and during exercise. As recently shown lowering of circulating BCAA level improves insulin sensitivity and cardiac metabolic health. However, little is known concerning the impact of a single bout of incremental exercise and physical training on the changes in blood BCAA. The present study aimed to determine the impact of a gradually increasing exercise intensity—up to maximal oxygen uptake (VO2max) on the changes of the plasma BCAA [∑BCAA]pl, before and after 5-weeks of moderate-intensity endurance training (ET).MethodsTen healthy young, untrained men performed an incremental cycling exercise test up to exhaustion to reach VO2max, before and after ET.ResultsWe have found that exercise of low-to-moderate intensity (up to ∼50% of VO2max lasting about 12 min) had no significant effect on the [∑BCAA]pl, however the exercise of higher intensity (above 70% of VO2max lasting about 10 min) resulted in a pronounced decrease (p < 0.05) in [∑BCAA]pl. The lowering of plasma BCAA when performing exercise of higher intensity was preceded by a significant increase in plasma lactate concentration, showing that a significant attenuation of BCAA during incremental exercise coincides with exercise-induced acceleration of glycogen utilization. In addition, endurance training, which significantly increased power generating capabilities at VO2max (p = 0.004) had no significant impact on the changes of [∑BCAA]pl during this incremental exercise.ConclusionWe have concluded that an exercise of moderate intensity of relatively short duration generally has no effect on the [∑BCAA]pl in young, healthy men, whereas significant decrease in [∑BCAA]pl occurs when performing exercise in heavy-intensity domain. The impact of exercise intensity on the plasma BCAA concentration seems to be especially important for patients with cardiometabolic risk undertaken cardiac rehabilitation or recreational activity.

Mortality and renal prognosis in isolated metformin‐associated lactic acidosis treated with continuous renal replacement therapy and citrate‐calcium‐anticoagulation

Use of metformin increases plasma lactate concentration and may lead to metformin-associated lactic acidosis (MALA). Previous studies have suggested severe MALA to have a mortality of 17%-21%, but have included patients with other coincident conditions such as sepsis. The treatment of choice is continuous renal replacement therapy (CRRT), which has been performed using heparin analogues or no anticoagulation in former studies. Patients admitted to the Intensive Care Unit of Turku University Hospital Finland with lactic acidosis without any other recognizable etiology than concomitant metformin treatment who required CRRT between years 2010 and 2019 were included. CRRT was performed using regional citrate-calcium-anticoagulation. Data extracted included patient demographics, comorbidities, and clinical parameters at 6-hour intervals about 72hours from admission. Creatinine and estimated glomerular filtration rate (eGFR) were measured at 1year after MALA. A total of 23 patients with isolated MALA were included in the study. Median (IQR) pH was 6.88 (6.81-7.07) and lactate 16.1 (11.9-23.0) mmol/L on admission. Median (IQR) duration of CRRT was 62 (41-70)hours. Seven patients (30%) required mechanical ventilation with a mean duration of 6.0±3.0days. 90-day mortality was 4.3% and 1-year mortality 13.0%. Creatinine (P=.02) and eGFR (P=.03) remained significantly altered at 1year of follow-up compared to baseline. MALA can be treated effectively and safely with CRRT and citrate-calcium-anticoagulation, usually required for 2-3days. Mortality of patients with MALA treated with CRRT is low when other conditions inducing lactic acidosis are excluded. MALA episode may be associated with long-lasting kidney injury.

Role of metformin in treatment of patients with chronic obstructive pulmonary disease: a systematic review.

Chronic obstructive pulmonary disease (COPD) is commonly associated with type 2 diabetes mellitus (T2DM). Metformin is a first-line treatment for most patients with T2DM, and may have antiaging, antioxidant, and anti-tumour effects. A few published studies report the use of metformin for the treatment of COPD in patients with or without T2DM, but the results are inconsistent. This study aimed to confirm the effectiveness and safety of metformin as a treatment option in patients with COPD. We performed a systematic search of PubMed, EMBASE, and the Cochrane database from their starting date to December 2017. Randomised controlled trials (RCTs), controlled clinical trials, and retrospective researches reporting the use of metformin for treating patients with COPD were identified. We included a total of six articles (involving 3,467 participants) and found that metformin may benefit patients with COPD and T2DM by improving health status and symptoms, hospitalisations, and mortality. There was no effect on patients with COPD without T2DM. Metformin causes minimal increases in plasma lactate concentrations without lactic acidosis and has little impact on blood glucose and minor adverse events. Metformin is safe and effective for treating COPD in patients with concomitant T2DM.

Impairment of Mitochondrial Redox Status in Peripheral Lymphocytes of Multiple Sclerosis Patients.

Literature suggests that oxidative stress (OS) may be involved in the pathogenesis of multiple sclerosis (MS), in which the immune system is known to play a key role. However, to date, the OS in peripheral lymphocytes and its contribution to the disease remain unknown. The aim of the present study was to explore the influence of OS in peripheral lymphocytes of MS patients. To that end, a cross-sectional, observational pilot study was conducted [n = 58: 34 MS and 24 healthy subjects (control group)]. We have measured superoxide production and protein mitochondrial complex levels in peripheral blood mononuclear cells (PBMCs) isolated from MS patients and control. Lactate levels and the antioxidant capacity were determined in plasma. We adjusted the comparisons between study groups by age, sex and cell count according to case. Results demonstrated that PBMCs, specifically T cells, from MS patients exhibited significantly increased superoxide anion production compared to control group (p = 0.027 and p = 0.041, respectively). Increased superoxide production in PBMCs was maintained after the adjustment (p = 0.044). Regarding mitochondrial proteins, we observe a significant decrease in the representative protein content of the mitochondrial respiratory chain complexes I-V in PBMCs of MS patients (p = 0.002, p = 0.037, p = 0.03, p = 0.044, and p = 0.051, respectively), which was maintained for complexes I, III, and V after the adjustment (p = 0.026; p = 0.033; p = 0.033, respectively). In MS patients, a trend toward increased plasma lactate concentration was detected [8.04 mg lactate/dL (5.25, 9.49) in the control group, 11.36 mg lactate/dL (5.41, 14.81) in MS patients] that was statistically significant after the adjustment (p = 0.013). This might be indicative of compromised mitochondrial function. Finally, antioxidant capacity was also decreased in plasma from MS patients, both before (p = 0.027) and after adjusting for sex and age (p = 0.006). Our findings demonstrate that PBMCs of MS patients show impaired mitochondrial redox status and deficient antioxidant capacity. These results demonstrate for the first time the existence of mitochondrial alterations in the cells immune cells of MS patients already at the peripheral level.

Hepatic metabolism of propionate relative to meals for cows in the postpartum period

The objective of this research was to identify potential short-term metabolic bottlenecks of propionate metabolism in the liver of dairy cows in the postpartum (PP) period and how such bottlenecks are affected by feeding status. Propionate, produced primarily from the fermentation of starch, decreases dry matter intake for cows in the postpartum period, likely by stimulating oxidation of acetyl-CoA in the liver. In this study, 8 dairy cows [2 blocks of 4 cows each, 6.63 ± 1.19 (mean ± SD) days PP; body condition score of 2.84 ± 0.39] were administered a pulse dose of either 1.5 mol/500 mL of propionic acid (PA) or 500 mL of water (control; CON) to the rumen either 1 h before or 2 h after feeding in a 4 × 4 Latin square design with a 2 × 2 factorial arrangement of treatments. Liver tissue was sampled at -1, 10 and 20 min relative to dosing, and blood was sampled at -30, -20, -10, -1, 5, 10, 15, 20, 25, 30, and 60 min relative to dosing. We hypothesized that rapid propionate absorption results in bottlenecks as enzymes become saturated and cofactors require regeneration. The PA treatment increased plasma propionate and insulin concentrations rapidly, with peaks reached by 5 min regardless of feeding status and cleared from the plasma within 30 min of dosing. The PA treatment decreased plasma nonesterified fatty acid concentration over 30 min compared with CON before but not after feeding. The PA treatment decreased plasma β-hydroxybutyrate concentration and increased plasma lactate concentration compared with CON both before and after feeding. The PA treatment also increased hepatic pyruvate and lactate concentrations compared with CON. The PA treatment tended to increase hepatic isocitrate and fumarate concentrations but did not affect hepatic malate and oxaloacetate concentrations, suggesting that elevated mitochondrial NADH/NAD+ may have slowed the isocitrate dehydrogenase and fumarase reactions. The PA treatment also increased succinate concentration compared with CON, suggesting that a bottleneck may be present at succinate dehydrogenase. The PA treatment tended to increase citrate concentration despite having no effects on acetyl-CoA or oxaloacetate concentrations. These results are in agreement with our hypothesis that rapid absorption of propionate from the rumen and extraction by the liver results in metabolic bottlenecks in the liver that may affect feeding behavior and dry matter intake in dairy cows in the PP period.

Evaluation of the anesthetic and cardiorespiratory effects of intramuscular alfaxalone administration and isoflurane in budgerigars (Melopsittacus undulatus) and comparison with manual restraint.

OBJECTIVE To evaluate the anesthetic and cardiorespiratory effects of IM alfaxalone and isoflurane administration in budgerigars (Melopsittacus undulatus) and compare use of these agents with use of manual restraint. ANIMALS 42 healthy budgerigars. PROCEDURES For dose comparison, birds received alfaxalone (5 or 10 mg/kg [2.27 or 4.54 mg/lb], IM; groups A5 and A10, respectively; n = 6/group). For treatment comparison, birds received alfaxalone (10 mg/kg, IM) or isoflurane (via face mask) or were manually restrained (groups A, I, and M, respectively; n = 10/group). Data were obtained on onset, degree, and duration of sedation or anesthesia; heart and respiratory rates; and recovery times. Birds in the treatment comparison underwent physical examination and blood gas analysis. RESULTS All group A5 birds became sedate, but not recumbent. In group A10, 5 of 6 birds lost the righting reflex; however, none lost the noxious stimulus response. Median time to initial effects was significantly shorter and mean time to complete recovery was significantly longer in group A10 than in group A5. Heart and respiratory rates in group A10 remained clinically acceptable; however, some birds had signs of excitement during induction and recovery. Times to initial effects, recumbency, and complete recovery were significantly longer, yet clinically practical, in group A than in group I. Plasma lactate concentrations were significantly higher in group M than in groups A and I. CONCLUSIONS AND CLINICAL RELEVANCE Alfaxalone administered IM at 10 mg/kg produced effective sedation in healthy budgerigars and may be a viable alternative to isoflurane and manual restraint for brief, minimally invasive procedures. Brief manual restraint resulted in a significant increase in plasma lactate concentration.

Association of plasma lactate concentration at admission of severe preeclampsia to maternal complications.

To evaluate in women with severe preeclampsia the association of lactate concentration at admission with maternal complications. A prospective cohort was created of women with severe preeclampsia consecutively admitted to an Obstetrical High-Dependency Unit. Plasma lactate concentration was measured at admission and its association to maternal complication was evaluated. A total of 100 women were included, of which 30 (30%) had a maternal complication. The mean lactate plasma concentration in this group was significantly higher than in those uncomplicated cases (2.38 vs 3.1 mmol/L; p < 0.01). A total of 37 (37%) women had lactate concentrations at >3 mmol/L, which was associated to higher incidence of maternal complications (19% vs. 48.6%; p = 0.002; OR 4.03 [95% CI 1.64-9.9]). This association remained independent of other standard severity criteria (OR 3.89; 95%CI 1.22-12.4; p = 0.022). Increased plasma lactate concentrations at admission in women with severe preeclampsia are independently associated to maternal complications.

Defining the contribution of skeletal muscle pyruvate dehydrogenase α1 to exercise performance and insulin action.

The pyruvate dehydrogenase complex (PDC) converts pyruvate to acetyl-CoA and is an important control point for carbohydrate (CHO) oxidation. However, the importance of the PDC and CHO oxidation to muscle metabolism and exercise performance, particularly during prolonged or high-intensity exercise, has not been fully defined especially in mature skeletal muscle. To this end, we determined whether skeletal muscle-specific loss of pyruvate dehydrogenase alpha 1 ( Pdha1), which is a critical subunit of the PDC, impacts resting energy metabolism, exercise performance, or metabolic adaptation to high-fat diet (HFD) feeding. For this, we generated a tamoxifen (TMX)-inducible Pdha1 knockout (PDHmKO) mouse, in which PDC activity is temporally and specifically ablated in adult skeletal muscle. We assessed energy expenditure, ex vivo muscle contractile performance, and endurance exercise capacity in PDHmKO mice and wild-type (WT) littermates. Additionally, we studied glucose homeostasis and insulin sensitivity in muscle after 12 wk of HFD feeding. TMX administration largely ablated PDHα in skeletal muscle of adult PDHmKO mice but did not impact energy expenditure, muscle contractile function, or low-intensity exercise performance. Additionally, there were no differences in muscle insulin sensitivity or body composition in PDHmKO mice fed a control or HFD, as compared with WT mice. However, exercise capacity during high-intensity exercise was severely impaired in PDHmKO mice, in parallel with a large increase in plasma lactate concentration. In conclusion, although skeletal muscle PDC is not a major contributor to resting energy expenditure or long-duration, low-intensity exercise performance, it is necessary for optimal performance during high-intensity exercise.

Effect of carbohydrate mouth rinse on exercise performance in horses

The mechanism related to the practice of oral carbohydrate (CHO) supplementation prior to intense exercise of a short duration (&lt;30 min) for athletic horses remains unclear. Several studies in human athletes showed that the central nervous system played an important role in the enhancement of athletic performance due to CHO contact with undefined receptors in the oropharyngeal mucosa. This study aims to investigate the influence of CHO mouth rinse on the exercise performance of horses. In this double blind, randomised, placebo-controlled study, seven Mangalarga Marchador horses underwent a standardised exercise test (SET) in a field. The following protocols involving a single mouthwash (1 litre) had been used: a mouth rinse of 6.4% maltodextrin-water solution (CHO test), and a mouth rinse of only water solution (placebo test). The mean plasma lactate concentration immediately after SET (lactate peak) was higher in the CHO test (24.33±3.72 mmol/l) than in the placebo test (18.19±4.01 mmol/l), (P&lt;0.001). No difference was observed in the mean time-to-exhaustion, mean and maximum heart rate, plasma glucose concentration and serum creatinine-kinase activity. Several studies described that there were improvements in the time-trial performance of cyclists and runners after a mouth rinse of CHO solution, whereas some did not. Carbohydrate mouth rinse had no influence on exercise performance in this study. Further investigations are required, as the significance of an increased plasma lactate concentration due to a CHO mouth rinse has yet to be elucidated.

Blockade of P-Glycoprotein Decreased the Disposition of Phenformin and Increased Plasma Lactate Level.

This study aimed to investigate the in vivo relevance of P-glycoprotein (P-gp) in the pharmacokinetics and adverse effect of phenformin. To investigate the involvement of P-gp in the transport of phenformin, a bi-directional transport of phenformin was carried out in LLC-PK1 cells overexpressing P-gp, LLC-PK1-Pgp. Basal to apical transport of phenformin was 3.9-fold greater than apical to basal transport and became saturated with increasing phenformin concentration (2–75 μM) in LLC-PK1-Pgp, suggesting the involvement of P-gp in phenformin transport. Intrinsic clearance mediated by P-gp was 1.9 μL/min while passive diffusion clearance was 0.31 μL/min. Thus, P-gp contributed more to phenformin transport than passive diffusion. To investigate the contribution of P-gp on the pharmacokinetics and adverse effect of phenformin, the effects of verapamil, a P-gp inhibitor, on the pharmacokinetics of phenformin were also examined in rats. The plasma concentrations of phenformin were increased following oral administration of phenformin and intravenous verapamil infusion compared with those administerd phenformin alone. Pharmacokinetic parameters such as Cmax and AUC of phenformin increased and CL/F and Vss/F decreased as a consequence of verapamil treatment. These results suggested that P-gp blockade by verapamil may decrease the phenformin disposition and increase plasma phenformin concentrations. P-gp inhibition by verapamil treatment also increased plasma lactate concentration, which is a crucial adverse event of phenformin. In conclusion, P-gp may play an important role in phenformin transport process and, therefore, contribute to the modulation of pharmacokinetics of phenformin and onset of plasma lactate level.

Fuel metabolism in Canada geese: effects of glucagon on glucose kinetics.

During prolonged fasting, birds must rely on glucose mobilization to maintain normoglycemia. Glucagon is known to modulate avian energy metabolism during prolonged fasting, but the metabolic effects of this hormone on long-distance migrant birds have never been investigated. Our goal was to determine whether glucagon regulates the mobilization of the main lipid and carbohydrate fuels in migrant birds. Using the Canada goose (Branta canadensis) as a model species, we looked for evidence of fuel mobilization via changes in metabolite concentrations. No changes could be found for any lipid fraction, but glucagon elicited a strong increase in glucose concentration. Therefore, we aimed to quantify the effects of this hormone on glucose kinetics using continuous infusion of 6-[(3)H]-d-glucose. Glucagon was found to cause a 50% increase in glucose mobilization (from 22.2 ± 2.4 μmol·kg(-1)·min(-1) to 33.5 ± 3.3 μmol·kg(-1)·min(-1)) and, together with an unchanged rate of carbohydrate oxidation, led to a 90% increase in plasma glucose concentration. This hormone also led to a twofold increase in plasma lactate concentration. No changes in plasma lipid concentration or composition were observed. This study is the first to demonstrate how glucagon modulates glucose kinetics in a long-distance migrant bird and to quantify its rates of glucose mobilization.

Caffeine ingestion after rapid weight loss in judo athletes reduces perceived effort and increases plasma lactate concentration without improving performance.

The objective of this study was to examine the effect of caffeine on judo performance, perceived exertion, and plasma lactate response when ingested during recovery from a 5-day weight loss period. Six judokas performed two cycles of a 5-day rapid weight loss procedure to reduce their body weight by ~5%. After weigh-in, subjects re-fed and rehydrated over a 4-h recovery period. In the third hour of this “loading period”, subjects ingested a capsule containing either caffeine (6 mg·kg−1) or placebo. One hour later, participants performed three bouts of a judo fitness test with 5-min recovery periods. Perceived exertion and plasma lactate were measured before and immediately after each test bout. Body weight was reduced in both caffeine and placebo conditions after the weight loss period (−3.9% ± 1.6% and −4.0% ± 2.3% from control, respectively, p < 0.05). At three hours after weigh-in, body weight had increased with both treatments but remained below the control (−3.0% ± 1.3% and −2.7% ± 2.2%). There were no significant differences in the number of throws between the control, caffeine or placebo groups. However, plasma lactate was systemically higher and perceived exertion lower in the subjects who ingested caffeine compared to either the control or placebo subjects (p < 0.05). In conclusion, caffeine did not improve performance during the judo fitness test after a 5-day weight loss period, but reduced perceived exertion and increased plasma lactate.

Presumptive cocaine toxicosis in 19 dogs: 2004-2012.

To characterize the incidence, signalment, presenting complaint, history, clinical signs, diagnostic test results, complications, treatment, length of hospitalization, and outcome of dogs presenting with presumptive cocaine toxicosis. Retrospective study from March 1, 2004 to March 1, 2012. Twenty-four hour urban university veterinary teaching hospital. Nineteen dogs presenting with clinical signs consistent with cocaine toxicosis and having a positive urine cocaine test. None. All dogs had neurological abnormalities including bilateral mydriasis (11/19 [58%]), hyperexcitability/hyperesthesia (10/19 [53%]), ataxia (8/19 [42%]), focal or generalized muscle tremors (8/19 [42%]), reduced mental awareness (6/19 [32%]), and seizures (3/19 [16%]). Other signs included weakness (7/19 [37%]), vomiting (6/19 [32%]), and lethargy (3/19 [16%]). Tachycardia was apparent in 10/19 (53%) dogs, hypertension in 4/19 (21%), and hyperthermia in 5/19 (26%). Sinus tachycardia was the only reported cardiac arrhythmia. Bloodwork findings included hyperglycemia in 4/19 (21%) dogs, and increased plasma lactate concentration in 9/19 (47%). Most dogs (16/19 [84%]) were hospitalized for supportive care, which generally included isotonic crystalloid fluid administration, and treatment with sedative or anxiolytic drugs including diazepam, midazolam, acepromazine, and chlorpromazine. Two dogs required further anticonvulsant therapy (phenobarbital and propofol) and 1 dog was treated with a constant rate infusion of esmolol. All dogs survived to discharge, and the median length of hospitalization was 15 hours (10-30 h). Cocaine toxicosis was infrequently suspected. Neurological signs predominated, but cardiovascular alterations were also frequently reported. Hospitalization for monitoring and supportive care is recommended given the potential for life-threatening complications such as seizures, hypertensive crisis, and tachyarrhythmias. The prognosis for survival to hospital discharge can be good with the appropriate supportive care.

Falsely increased plasma lactate concentration due to ethylene glycol poisoning in 2 dogs

To describe false increases in plasma lactate concentration measured on point-of-care analyzers in 2 dogs with ethylene glycol (EG) intoxication. Two dogs presenting with EG intoxication had extreme increases of plasma lactate concentrations recorded on a point-of-care machine. Laboratory analysis by spectrophotometry of lactate concentration determined these lactate measurements to be erroneous. False increases in plasma lactate concentration were demonstrated in 2 out of 3 point-of-care machines tested. Glycolate, a toxic metabolite of EG, can interfere with the measurement of plasma lactate by some analyzers and this may delay the correct diagnosis of EG toxicity if not recognized.

Whole body surface cooling before aerobic exercise decreases lactate threshold in cool environment

Whole body surface cooling prior to exercise improves aerobic performance in the heat, while possible effects of the procedure on aerobic performance in cool environment are remained unknown. Sympathetic nerve activity and glycolysis are enhanced by body surface cooling, therefore we hypothesized that whole body surface cooling prior to exercise increased plasma lactate concentration [Lac]p before and during aerobic exercise and declined lactate threshold (LT) in cool environment.MethodsSix healthy young women and men performed a graded maximal exercise on a cycling ergometer after pre‐conditioning (60 min) in 3 conditions. The ambient temperature (Ta) and a water perfusion suit temperature (Tw) were controlled at Ta10°C‐Tw10°C in Cool‐Cool (CC), Ta25°C‐Tw10°C in Mild‐Cool (MC), Ta25°C‐Tw34°C in Mild‐Neutral (MN), respectively. [Lac]p, heart rate, blood pressure, expired gas, esophageal (Tes) and skin temperature (Tsk) were measured and LT was determined.ResultsTes was higher and Tsk was lower in CC and MC than MN after pre‐conditioning, respectively. [Lac]p after pre‐conditioning and during each workload of exercise were higher in the order of CC, MC, MN, while LT showed lower values in the same order. [Lac]p at exhaustion was the lowest in CC.ConclusionsWhole Body surface cooling before aerobic exercise increased [Lac]p before and during exercise and decreased LT in cool environment.