Decrease In Lactate Concentration Research Articles

Acute Effect of Passive Hyperthermia on Lactate Concentrations

Background: Knowledge on the effect of heat on recovery is still incomplete. The present study aimed to evaluate the effect of a passive acute hyperthermic stimulus before and after a lactic anaerobic test on the production and oxidation of lactate blood concentrations. In addition, the purpose was to evaluate the effect that the application of this previous hyperthermic stimulus may have on the athletic performance in the test. Methods: For this purpose, a cross-over design through an anaerobic treadmill test in three different situations (normothermia, pre-test hyperthermia, and post-test hyperthermia) was performed. Twelve male subjects participated (age: 21.25 ± 1.64 years; height: 1.76 m ± 0.08; weight: 72.59 ± 9.44 kg). An anthropometric assessment was carried out with weight, height, skinfolds, body perimeters and diameters, and external and internal body temperatures in each of the tests. A nutritional survey was also carried out 48 h prior to each test. Results: The results of the study showed a decrease in blood lactate concentrations when the hyperthermic effect was applied as passive recovery just after the end of the test (p < 0.05). A decrease in lactate concentrations was also achieved when applying the hyperthermic effect just before the start of the test (p < 0.05). However, no significant improvements were obtained from this application of heat on test performance. Conclusions: The results suggest that the application of passive acute hyperthermia has a favourable effect in terms of decreasing blood lactate concentrations in a 5 min recovery period after lactic anaerobic activity.

Novel sulfonamides unveiled as potent anti-lung cancer agents via tumor pyruvate kinase M2 activation.

This rational pursuit led to the identification of a novel sulfonamide derivative as a potent anti-lung cancer (LC) compound. Considering these results, we synthesized 38 novel sulfonamide derivatives with diverse skeletal structures. In vitro cytotoxicity assays revealed a potent and selective antiproliferative effect against A549 cells after evaluating a panel of cancer cell lines. Compound 9b has emerged as a potent activator of tumor pyruvate kinase M2 (PKM2), a protein known to play a critical role in LC. Apoptosis assays and cell cycle analysis demonstrated early apoptosis and G2 phase arrest. In silico studies demonstrated interactions between compound 9b and the activator binding site of PKM2. Surface plasmon resonance (SPR) experiments strongly indicated that 9b has a high affinity (K d of 1.378 nM) for PKM2. Furthermore, the increase in reactive oxygen species and decrease in lactate concentration suggested that compound 9b has significant anticancer effects. Notably, the increase in particle size following treatment with 9b suggested the tetramerization of PKM2. This work provides insights that might advance efforts to develop effective non-platinum anticancer agents.

Production of bacterial cellulose (BC)/nisin composite with enhanced antibacterial and mechanical properties through co-cultivation of Komagataeibacter xylinum and Lactococcus lactis subsp. lactis

By employing co-cultivation technique on Komagataeibacter xylinum and Lactococcus lactis subsp. lactis, bacterial cellulose (BC)/nisin films with improved antibacterial activity and mechanical properties were successfully produced. The findings demonstrated that increased nisin production is associated with an upregulation of gene expression. Furthermore, results from Scanning electronic microscopy (SEM), Fourier transform infrared (FTIR), X-ray diffraction (XRD), and Thermogravimetric analysis (TG) confirmed the integration of nisin within BC. While being biocompatible with human cells, the BC/nisin composites exhibited antimicrobial activity. Moreover, mechanical property analyses showed a noticeable improvement in Young's modulus, tensile strength, and elongation at break by 161, 271, and 195 %, respectively. Additionally, the nisin content in fermentation broth was improved by 170 % after co-culture, accompanied by an 8 % increase in pH as well as 10 % decrease in lactate concentration. Real-time reverse transcription PCR analysis revealed an upregulation of 11 nisin-related genes after co-cultivation, with the highest increase in nisA (5.76-fold). To our knowledge, this is the first study which demonstrates that an increase in secondary metabolites after co-culturing is modulated by gene expression. This research offers a cost-effective approach for BC composite production and presents a technique to enhance metabolite concentration through the regulation of relevant genes.

Investigation of the biological activity of the water-soluble C<sub>60</sub>/poly-<i>N</i>-vinylpyrrolidone complex

Objectives. The study aimed to investigate the biological activity of the C60/poly-N-vinylpyrrolidone (C60/PVP) complex representing a water-soluble fullerene derivative. In vitro and in vivo techniques were used to analyze the effect of the C60/PVP complex on the activity of lactate dehydrogenase (LDH) and evaluate changes in the biochemical parameters of blood serum when per os administered to mice.Methods. In order to determine the activity of a commercial LDH preparation and study the kinetics of this process, the standard Warburg photometric method was used. To assess the effect of polyvinylpyrrolidone (PVP) and the C60/PVP complex on some biochemical parameters in vivo, a study was conducted on two-month-old male white mongrel mice weighing 20 ± 3 g. Determination of biochemical parameters of blood serum was carried out using a semi-automatic biochemical analyzer according to standard methods.Results. The effect of the C60/PVP complex on LDH activity was studied along with changes in the biochemical parameters of mouse blood serum characterizing carbohydrate metabolism. As well as increasing the glucose and pyruvic acid content, the C60/PVP complex was found to reduce lactate content and LDH activity in blood serum along with in vitro LDH activity according to the type of mixed inhibition.Conclusions. The C60/PVP complex and PVP were shown to exhibit biological activity in vitro and in vivo. The C60/PVP complex, representing a mixed-type LDH inhibitor, was shown to inhibit LDH activity, as well as contributing to a decrease in lactate concentration and an increase in the concentration of pyruvic acid and glucose in blood serum when administered per os to mice. The inhibitory effect of PVP on LDH activity was revealed in both in vivo and in vitro investigations. In vivo, PVP contributes to a decrease in the concentration of lactate in the blood. The less pronounced effect of the C60/PVP complex as compared to PVP alone may be due to the fact that C60 molecules are “hidden” in cavities formed in PVP molecules.

INFLUENCE OF CREATINE MONOHYDRATE ON BIOCHEMICAL PARAMETERS AND SPEED ENDURANCE OF WOMAN FOOTBALL PLAYERS

The aim of the research is to investigate the effect of 28 days of creatine monohydrate use in football players after a test exercise on speed endurance and biochemical parameters. The data obtained indicate that as a result of daily usage of 0.1 g / kg of creatine monohydrate according to muscle mass for 28 days, the indicators of speed endurance were improved by a significant 8.40% (an increase in the number of steps in the test exercise), which after completing the test task affected the biochemical data, where the creatinine level was decreased by 3.40%, the indicators of creatine phosphokinase were decreased by 2.37% and lactate concentration were decreased by an average of 26.40%. The data obtained indicate that using creatine monohydrate at a dose of 0.1 g / kg according to muscle mass per day contributed to an increase in speed endurance, in particular, an increase in the creatine reserve in the muscles, which is seen in decrease of lactate concentration after completing a test workout. The decrease of creatinine and creatine phosphokinase indicates less muscle breakdown and, consequently, a decrease in excretion in blood in general, especially in vein blood.

Effect of a High Fat Diet vs. High Carbohydrate Diets With Different Glycemic Indices on Metabolic Parameters in Male Endurance Athletes: A Pilot Trial.

Consuming low glycemic carbohydrates leads to an increased muscle fat utilization and preservation of intramuscular glycogen, which is associated with improved flexibility to metabolize either carbohydrates or fats during endurance exercise. The purpose of this trial was to investigate the effect of a 4-week high fat low carbohydrate (HFLC-G: ≥65% high glycemic carbohydrates per day; n = 9) vs. high carbohydrate low glycemic (LGI-G: ≥65% low glycemic carbohydrates daily; n = 10) or high glycemic (HGI-G: ≥65% fat, ≤ 50 g carbohydrates daily; n = 9) diet on fat and carbohydrate metabolism at rest and during exercise in 28 male athletes. Changes in metabolic parameters under resting conditions and during cycle ergometry (submaximal and with incremental workload) from pre- to post-intervention were determined by lactate diagnostics and measurements of the respiratory exchange ratio (RER). Additionally, body composition and perceptual responses to the diets [visual analog scale (VAS)] were measured. A significance level of α = 0.05 was considered. HFLC-G was associated with markedly decreased lactate concentrations during the submaximal (−0.553 ± 0.783 mmol/l, p = 0.067) and incremental cycle test [−5.00 ± 5.71 (mmol/l) × min; p = 0.030] and reduced RER values at rest (−0.058 ± 0.108; p = 0.146) during the submaximal (−0.078 ± 0.046; p = 0.001) and incremental cycle test (−1.64 ± 0.700 RER × minutes; p < 0.001). In the HFLC-G, fat mass (p < 0.001) decreased. In LGI-G lactate, concentrations decreased in the incremental cycle test [−6.56 ± 6.65 (mmol/l) × min; p = 0.012]. In the LGI-G, fat mass (p < 0.01) and VAS values decreased, indicating improved levels of gastrointestinal conditions and perception of effort during training. The main findings in the HGI-G were increased RER (0.047 ± 0.076; p = 0.117) and lactate concentrations (0.170 ± 0.206 mmol/l, p = 0.038) at rest. Although the impact on fat oxidation in the LGI-G was not as pronounced as following the HFLC diet, the adaptations in the LGI-G were consistent with an improved metabolic flexibility and additional benefits regarding exercise performance in male athletes.

Effects of Supplementation with Ginseng and Branched Chain Amino Acids Improved Central Fatigue and Enhanced Attention during Exercise: A Randomized, Double-blind, Placebo Controlled

Muscle fatigue was a common problem after exercise. When fatigue occured, body functions were affected and changed. Changbai Mountain ginseng had higher anti-fatigue substances than general commercial ginseng. And recent studies had showed that the supplementation of branched chain amino acids (BCAA), including leucine, isoleucine and valine, can increase attention and reduce fatigue. However, its effect on Changbai Mountain ginseng combined with BCAA was still unclear. Subjects were allocated to Gojinsen® drinks and placebo group (1:1 ratio) for 14 days, and then examined by maximal oxygen consumption, time to exhaustion, rating of perceived exertion (RPE), oxygen saturation (SPO2), blood lactate concentration, and continuous attention performance test (CPT II). The Gojinsen® group significant increased maximal oxygen consumption, time to exhaustion, and attention compared to placebo group. Moreover, the Gojinsen® group significant decreased lactate concentration and fatigue compared to placebo group. By our study, Gojinsen® drinks had anti-fatigue effect and enhanced attention, and the therapeutic potential for people suffering from exercise fatigue.

Lactate is associated with mortality in very old intensive care patients suffering from COVID-19: results from an international observational study of 2860 patients

PurposeLactate is an established prognosticator in critical care. However, there still is insufficient evidence about its role in predicting outcome in COVID-19. This is of particular concern in older patients who have been mostly affected during the initial surge in 2020.MethodsThis prospective international observation study (The COVIP study) recruited patients aged 70 years or older (ClinicalTrials.gov ID: NCT04321265) admitted to an intensive care unit (ICU) with COVID-19 disease from March 2020 to February 2021. In addition to serial lactate values (arterial blood gas analysis), we recorded several parameters, including SOFA score, ICU procedures, limitation of care, ICU- and 3-month mortality. A lactate concentration ≥ 2.0 mmol/L on the day of ICU admission (baseline) was defined as abnormal. The primary outcome was ICU-mortality. The secondary outcomes 30-day and 3-month mortality.ResultsIn total, data from 2860 patients were analyzed. In most patients (68%), serum lactate was lower than 2 mmol/L. Elevated baseline serum lactate was associated with significantly higher ICU- and 3-month mortality (53% vs. 43%, and 71% vs. 57%, respectively, p < 0.001). In the multivariable analysis, the maximum lactate concentration on day 1 was independently associated with ICU mortality (aOR 1.06 95% CI 1.02–1.11; p = 0.007), 30-day mortality (aOR 1.07 95% CI 1.02–1.13; p = 0.005) and 3-month mortality (aOR 1.15 95% CI 1.08–1.24; p < 0.001) after adjustment for age, gender, SOFA score, and frailty. In 826 patients with baseline lactate ≥ 2 mmol/L sufficient data to calculate the difference between maximal levels on days 1 and 2 (∆ serum lactate) were available. A decreasing lactate concentration over time was inversely associated with ICU mortality after multivariate adjustment for SOFA score, age, Clinical Frailty Scale, and gender (aOR 0.60 95% CI 0.42–0.85; p = 0.004).ConclusionIn critically ill old intensive care patients suffering from COVID-19, lactate and its kinetics are valuable tools for outcome prediction.Trial registration number: NCT04321265.

Enzymatic activation of pyruvate kinase increases cytosolic oxaloacetate to inhibit the Warburg effect.

Pharmacological activation of the glycolytic enzyme PKM2 or expression of the constitutively active PKM1 isoform in cancer cells results in decreased lactate production, a phenomenon known as the PKM2 paradox in the Warburg Effect. Here we show that oxaloacetate (OAA) is a competitive inhibitor of human lactate dehydrogenase A (LDHA) and that elevated PKM2 activity increases de novo synthesis of OAA through glutaminolysis, thereby inhibiting LDHA in cancer cells. We also show that replacement of human LDHA with rabbit LDHA, which is relatively resistant to OAA inhibition, eliminated the paradoxical correlation between the elevated PKM2 activity and the decreased lactate concentration in cancer cells treated with a PKM2 activator. Furthermore, rabbit LDHA-expressing tumors displayed resistance to the PKM2 activator compared to human LDHA-expressing tumors in mice. These findings describe a mechanistic explanation for the PKM2 paradox by showing that OAA accumulates to inhibit LDHA following PKM2 activation.

Low doses of monensin for lambs fed diets containing high level of ground flint corn

Two experiments were proposed to evaluate the addition of monensin for lambs fed diets containing a high level of mature ground flint corn. The experimental diets were as follows: no inclusion of monensin (M0) and inclusion of 8 (M8), 16 (M16) and 24 mg kg–1 of monensin (M24). In experiment 1, eight cannulated wethers were divided into a double 4 × 4 Latin square experimental design to evaluate nutrient digestibility, plasma parameters and rumen fermentation. The experiment lasted 112 days, divided into four periods of 28 days each. In experiment 2, ninety-two lambs were used in a randomized block design to evaluate the performance over 56 days. In experiment 1, doses of monensin had no effect on nutrient intake (p ≥ 0.07) and digestibility (p ≥ 0.09). There was a quadratic effect for acetate molar proportion (p = 0.01), acetate to propionate ratio (p = 0.04) and rumen pH (p < 0.01). However, there was no effect on the molar proportion of propionate and butyrate. The monensin decreased linearly the total SCFA concentration (p < 0.01). The inclusion of monensin increased glucose (p < 0.01) and decreased lactate concentration in plasma (p = 0.05). In experiment 2, monensin decreased dry matter intake (p = 0.04). However, there was a quadratic effect for average daily gain (p = 0.03) and feed efficiency (p < 0.01), with the greatest values observed for the M8 diet. Thus, the inclusion of 8 mg kg–1 of dry matter diet (DM) improves ruminal fermentation and plasma parameters, resulting in greater growth performance in lambs.

Effects of Vasopressin Infusion After Pediatric Cardiac Surgery: A Meta-analysis.

Vasopressin has been used to augment blood pressure; however, cardiovascular effects after cardiac surgery have not been well established. The primary objective of this study was to survey the current literature and quantify the pooled effect of vasopressin on hemodynamic parameters in children after pediatric cardiac surgery. A systematic review was conducted to identify studies characterizing the hemodynamic effects of vasopressin after pediatric cardiac surgery. Studies were assessed and those of satisfactory quality with pre- and post-vasopressin hemodynamics for each patient were included in the final analyses. 6 studies with 160 patients were included for endpoints during the first 2h of infusions. Patients who received vasopressin infusion had greater mean, systolic, and diastolic blood pressures and lower heart rates at 2h after initiation. 8 studies with 338 patients were included for the effects at 24h. Patients who received vasopressin infusion had lower central venous pressures and decreased lactate concentrations 24h after initiation. A subset analysis for children with functionally univentricular hearts found significant decrease in inotrope score and central venous pressure. A subset analysis for neonates found significant decrease in inotrope score and fluid balance. Vasopressin leads to decrease in heart rate and increase in blood pressure in the first 2h of initiation. Later effects include decrease in inotrope score, central venous pressure, fluid balance, and in lactate within the first 24h. Findings vary in neonates and in those with functionally univentricular hearts although beneficial effects are noted in both.

Inhibition of glycolysis by targeting lactate dehydrogenase A facilitates hyaluronan synthase 2 synthesis in synovial fibroblasts of temporomandibular joint osteoarthritis.

Although associations between dysregulated glucose metabolism and human rheumatoid arthritis have been reported, the disturbance and influence of glycolytic metabolism on temporomandibular joint osteoarthritis remains unclear. This study aimed to investigate the expression level and metabolite profile of the critical glycolytic enzyme, lactate dehydrogenase A (LDHA) in synovial fibroblasts (SFs) of TMJOA, assess the effect of glycolytic inhibition on synthesis of hyaluronan synthase 2 (HAS2) and inflammation progression in these cells. Immunohistochemistry and western blotting were performed to detect the expression of LDHA in the lining and sub-lining layers of synovial tissue and SFs. MTT and EdU assays were used to measure the cell proliferation. The cell apoptosis were demonstrated by TUNEL staining and Annexin V/PI double staining. A potent and specific inhibitor of LDHA, GSK2837808A, was administrated to suppress the activity of LDHA and detect the potential efficacy on HAS2. LDHA expression was dramatically higher in the synovial tissue and SFs from TMJOA patients compared to control groups. LDHA inhibition impaired active LDHA performance, suppressed the glucose uptake and decreased lactate concentration. Furthermore, GSK2837808A reversed the occurrence of low ratio of ATP/AMP, high level of Adenosine Monophosphate-activated Protein Kinase (AMPK) activation, disturbed HAS2 synthesis and hyaluronic acid (HA) production by inhibiting LDHA. The cellular viability and cell cycle were not affected by GSK2837808A at the working concentration. Targeting LDHA using its specific suppressant GSK2837808A impeded lactate secretion and contributed to HAS2 and HA synthesis in TMJOA SFs, providing the vital role of LDHA associated with TMJOA pathogenesis and a novel therapeutic approach for TMJOA.

Decreased Blood Glucose and Lactate: Is a Useful Indicator of Recovery Ability in Athletes?

During low-intensity exercise stages of the lactate threshold test, blood lactate concentrations gradually diminish due to the predominant utilization of total fat oxidation. However, it is unclear why blood glucose is also reduced in well-trained athletes who also exhibit decreased lactate concentrations. This review focuses on decreased glucose and lactate concentrations at low-exercise intensity performed in well-trained athletes. During low-intensity exercise, the accrued resting lactate may predominantly be transported via blood from the muscle cell to the liver/kidney. Accordingly, there is increased hepatic blood flow with relatively more hepatic glucose output than skeletal muscle glucose output. Hepatic lactate uptake and lactate output of skeletal muscle during recovery time remained similar which may support a predominant Cori cycle (re-synthesis). However, this pathway may be insufficient to produce the necessary glucose level because of the low concentration of lactate and the large energy source from fat. Furthermore, fatty acid oxidation activates key enzymes and hormonal responses of gluconeogenesis while glycolysis-related enzymes such as pyruvate dehydrogenase are allosterically inhibited. Decreased blood lactate and glucose in low-intensity exercise stages may be an indicator of recovery ability in well-trained athletes. Athletes of intermittent sports may need this recovery ability to successfully perform during competition.

Heart rate and blood lactate responses during the cross-country test of 2-star to 5-star eventing competitions

The objective of this retrospective study was to evaluate the physiological demands of cross-country competitions at different levels. Heart rates (HR) and post exercise blood lactate concentrations (LAC) measured between 2010 and 2019 in response to 1,463 cross-country competitions (437 at 2-star, 703 at 3-star, 313 at 4-star and 10 at 5-star level) in 294 horses were analysed. The effect of competition level, mean velocity, height profile, total distance, number of jumping efforts, climate, age, sex, percentage of Thoroughbred blood and performance level on HR, LAC, HR recovery and LAC disappearance rates was evaluated by Linear Mixed Effects Models. Mean HR and LAC significantly increased from 2-star to 4-star level (P&lt;0.001). Each 30 m/min increase in mean velocity was associated with a 3 beats/min increase in HR (P&lt;0.001) and a 41% increase in LAC (P&lt;0.001) and each 30 m increase in cumulative elevation with a 2 beats/min increase in HR (P&lt;0.001) and a 32% increase in LAC (P&lt;0.001). Each 20 m increase in mean distance per jumping effort was associated with a 1 beat/min decrease in HR (P&lt;0.01) and a 13% decrease in LAC (P&lt;0.001). Compared to Warmbloods, horses with 75% Thoroughbred blood had 4 beats/min lower HRs (P&lt;0.05) and 34% lower LAC values (P&lt;0.001). Each 5 years increase in age was associated with a 4 beats/min decrease in HR (P&lt;0.001, only in mares) and an 11% decrease in LAC (P&lt;0.01). The HRs during the first 3 minutes of recovery were higher at warmer and more humid conditions (P&lt;0.05). The rate of LAC disappearance was higher in horses with higher percentages of Thoroughbred blood (P&lt;0.05).

Does the type of foam roller influence the recovery rate, thermal response and DOMS prevention?

Supporting post-exercise recovery requires choosing not only the right treatment but also the equipment, in which the impact is not always clear. The study aimed to determine the effect of foam rolling on the rate of lactate removal and DOMS prevention and whether the type of foam roller is effective in the context of post-exercise recovery. This randomized trial enrolled 33 active healthy males divided into three groups of eleven individuals: foam rolling with a smooth (STH) or grid roller (GRID) or passive recovery (PAS). All the participants performed full squat jumps for one minute. Examination took place at rest (thermal imaging of skin temperature-[Tsk] and blood lactate-[LA]), immediately following exercise (Tsk & LA), immediately after recovery treatment (Tsk) and after 30 minutes of rest (Tsk & LA). Their pain levels were assessed using the Visual Analog Scale (VAS) 24, 48, 72, and 96 hours after exercise. The magnitude of lactate decrease depended on the type of recovery used. In the PAS group, the decrease in lactate concentration by 2.65 mmol/L following a half-hour rest was significantly lower than that in the other groups (STH vs. PAS p = 0.042 / GRID vs. PAS p = 0.025). For thermal responses, significant differences between both experimental groups were noted only 30 minutes after exercise. A significant decrease in pain in the STH group occurred between 48 and 96 hours, while the GRID group showed a systematic significant decrease in VAS values in subsequent measurements. Changes in VAS values in subsequent measurements in the PAS group were not statistically significant (p>0.05). Foam rolling seems to be effective for enhancing lactate clearance and counteracting DOMS, but the type of foam roller does not seem to influence the recovery rate.

Resuscitation from Hemorrhagic Shock after Traumatic Brain Injury with Polymerized Hemoglobin

Hemorrhagic Shock (HS) after Traumatic Brain Injury (TBI) is common and lethal among military and civilians. Blood transfusion has been the resuscitation gold standard procedure for many years. However, only 3% of age‐eligible individuals donate blood, which limits blood availability and cannot meet current blood demands. This study was compared the efficacy to resuscitate from HS after TBI via infusion of Lactated Ringer’s solution (LR, electrolyte solution used to restore the loss of blood volume), fresh blood (Blood, autologous blood drawn during the hemorrhage), or Polymerized Hemoglobin [PolyHb, a Hemoglobin Based Oxygen Carrier (HBOC) that shows promise in increasing oxygenation]. Fifteen Wistar rats (350–400g) were instrumented with catheters in the femoral artery and vein and subjected to TBI through a pneumatic controlled cortical impact (CCI) (Leica Biosystems, Vista, CA). To induce TBI, a 5mm craniotomy over the right cerebral cortex was performed, and the scalp was impacted at a velocity of 5m/s and dwell time of 200ms. The scalp was subsequently closed and animals were given 10 min to stabilize before performing HS. HS was induced by blood withdrawal from the femoral artery catheter to achieve a mean arterial pressure (MAP) between 35–40mmHg, and the hypotensive state was maintained for 90 min before resuscitation. Animals were separated into 3 groups based on the resuscitation solution: Blood, LR, or PolyHb. Animals were monitored for an additional 120 min before euthanasia. Measurements were taken at baseline (BL), 90 min into HS (HS), and 30 min (R1) and 2 hours (R2) after resuscitation. The MAP, systolic blood pressure (SBP), and diastolic blood pressure (DBP) were decreased equally in all groups during HS. Blood and PolyHb groups increased MAP compared to the LR group at R1. The MAP was not different between Blood and PolyHb at R2. The SBP was increased only for the Blood group as compared to the LR group at R1. Moreover, DBP was increased for both Blood and PolyHb compared to the LR group at R1 and R2. As expected, hematocrit decreased in all groups after HS, with only the Blood group recovering hematocrit after resuscitation. Total hemoglobin (tHb) decreased after HS, and increased after resuscitation for the Blood and PolyHb groups but not in the LR group. Oxygen saturation was decreased for the Blood and PolyHb groups compared to the LR group at R1 and R2. The oxygen saturation was increased on the Blood group compared to PolyHb group at R2. After HS all groups increased lactate, after R1 just Blood and LR group recovered lactate to BL levels, and PolyHb did not decreased lactate concentration at R2 compared to the blood group. In conclusion, our results show that PolyHb was effective to resuscitation from HS after TBI, restoring blood pressure similarly to Blood group and could be a good alternative to transfusion for field resuscitation from HS after TBI.Support or Funding InformationThis work was supported by the NIH Heart Lung and Blood Institute under Grant, R01‐HL126945, and the DOD DMRDP under Grants W81XWH‐18‐1‐0059, W81XWH‐17‐2‐0047

Ammonium Salts Increase Physical Performance and Reduce Blood Lactate Level in Rats in a Model of Forced Swimming.

We compared the effects of two doses of ammonium chloride and ammonium carbonate (10 and 20 mg/kg) on the duration of swimming and blood lactate level. Ammonium chloride in a dose of 20 mg/kg was more efficient than in a dose of 10 mg/kg. The efficiency of ammonium carbonate in a dose of 10 mg/kg was similar to that of ammonium chloride in a dose of 20 mg/kg. Increasing the dose of ammonium carbonate to 20 mg/kg led to a decrease in the duration of swimming. On the last day of the experiment, lactate level in 5 min after exhausting load was maximum in control rats, while in rats treated with 10 mg/kg ammonium carbonate and 20 mg/kg ammonium chloride it was lower by 27 and 33%, respectively. In the control group, the amplitude of the decrease in lactate concentration in 1 h after load was 2-fold greater than in the group receiving ammonium chloride in a dose of 20 mg/kg and 1.6-fold greater that in groups treated with ammonium carbonate in a dose of 10 mg/kg and ammonium chloride in a dose of 20 mg/kg.

Effects of sildenafil citrate on peripheral fatigue and exercise performance after exhaustive swimming exercise in rats.

Sildenafil citrate is a potent and selective inhibitor of phosphodiesterase type-5 used to treat erectile dysfunction. We investigated the effects of sildenafil citrate treatment on peripheral fatigue and exercise performance after exhaustive swimming exercise in rats. The rats in the sildenafil citrate-treated groups received sildenafil citrate orally once a day for 14 consecutive days at respective dosage. On the 14 days after starting experiment, each animal was submitted to swimming test with intensity equivalent to overload. The exhaustion was defined as a state in which coordinated movements did not return to the water surface for breathing within 10 sec. Western blot for monocarboxylate transporter (MCT)1, MCT4, and neuronal nitric oxide synthase (nNOS) were performed. Exhaustive swimming exercise decreased time of exhaustion and increased lactate concentration, however, sildenafil citrate enhanced time of exhaustion and decreased lactate concentration. Exhaustive swimming exercise increased MCT1 and MCT4 expressions in the gastrocnemius muscles and sildenafil citrate further enhanced MCT1 and MCT4 expressions in the exhaustive swimming exercise rats. Exhaustive swimming exercise decreased nNOS expression in the gastrocnemius muscles and sildenafil citrate enhanced nNOS expression in the exhaustive swimming exercise rats. The most potent effect appeared in the 20-mg/kg sildenafil citrate. Sildenafil citrate might be proposed as a potential ergogenic aid through antiperipheral fatigue.

États de choc : grands cadres étiologiques, prise en charge initiale

Shock states are the leading causes of intensive care admission and are nowadays associated with high morbidity and mortality. They are driven by a complex physiopathology and most frequently a multifactorial mechanism. They can be separated in whether a decrease of oxygen delivery (quantitative shock) or an abnormal cell distribution of cardiac output (distributive shock). Septic, cardiogenic and hypovolemic shocks represent more than 80% of shock etiologies. Clinical presentation is mostly characterized by frequent arterial hypotension and sign of poor clinical perfusion. Hyperlactatemia occurs in most of shock states. The diagnostic of shock or earlier reversible “pre-shock” states is urgent in order to initiate adequate therapy. Therefore, orientation and therapies must be discussed with intensive care physiologists in a multidisciplinary approach. Etiologic investigation and correction is a primary concern. Hemodynamic and respiratory support reflect another part of initial therapy toward normalization of cell oxygenation. Fluid resuscitation is the corner stone part of initial therapy of any form of shock. Vasoconstrictive drugs or inotropic support still often remain necessary. The primary goal of initial resuscitation should be not only to restore blood arterial pressure but also to improve clinical perfusion markers. On the biological side, decrease of lactate concentration is associated with better outcome.

Effectiveness of Upper Body Compression Garments Under Competitive Conditions: A Randomised Crossover Study withEliteCanoeists with an Additional Case Study

This study aimed to investigate the effects of upper body compression garments on performance changes in elite canoeists. A total of 23 elite athletes from the German Canoe Federation (6 women and 17 men) were recruited. On a regatta lake, the athletes completed a 1650-m test track with their competition or training boats and paddles. The athletes were randomised into two groups and performed the test track with and without upper body compression garments. Besides split and end times, capillary blood lactate concentrations were assessed. For statistical analysis, an effect-based approach ("Magnitude-Based Inferences") and an additional case study were conducted. For this purpose, the mean and individual effects were examined in relation to the smallest worthwhile changes. On average, the effect-based approach shows that upper body compression garments do not lead to clear changes in performance. The changes in lactate concentrations were clear, but were considered trivial. In contrast to the average statistical analysis, the results of the case study demonstrate that upper body compression garments lead to an improved performance in 13.0 % and a worsened performance in 4.4 % of athletes. Additionally, a decreased lactate concentration was found in 4.4 % and an increased lactate concentration in 17.4 % of athletes. Our study shows that, on average, upper body compression garments have no effects on the performance and lactate concentration of highly trained elite canoeists. In individual cases, however, there are beneficial as well as harmful effects that may have practical relevant consequences for elite athletes.