Plasma Creatine Kinase Activity Research Articles

Effect of Staphylococcus Aureus infection on plasma creatine kinase activity in rabbits

Effect of Staphylococcus Aureus infection on plasma creatine kinase activity in rabbits

The association of Hsp90 expression induced by aspirin with anti-stress damage in chicken myocardial cells.

The protective effect of aspirin during exposure to heat stress in broiler chickens was investigated. We assayed pathological damage, expression and distribution of Hsp90 protein and hsp90 mRNA expression in chicken heart tissues after oral administration of aspirin following exposure to high temperature for varying times. Heat stress induced increases in plasma aspartate aminotransferase, creatine kinase and lactate dehydrogenase activities while causing severe heart damage, which was characterized by granular and vacuolar degeneration, nuclear shrinkage and even myocardium fragmentation in cardiac muscle fibers. After aspirin administration, myocardial cells showed fewer pathological lesions than broilers treated with heat alone. A high positive Hsp90 signal was always detected in the nuclei of myocardial cells from broilers treated with aspirin, while in myocardial cells treated with heat alone, Hsp90 in the nuclei decreased, as did that in the cytoplasm. Aspirin induced rapid and significant synthesis of Hsp90 before and at the initial phase of heat stress, and significant expression of hsp90 mRNA was stimulated throughout the experiment when compared with cells exposed to heat stress alone. Thus, specific pre-induction of Hsp90 in cardiovascular tissue was useful for resisting heat stress damage because it produced stable damage-related enzymes and fewer pathologic changes.

Low temperature stress on the hematological parameters and HSP gene expression in the turbot Scophthalmus maximus

To study the effect of low temperature stress on hematological parameters and HSP gene expression in the turbot (Scophthalmus maximus), water temperature was lowered rapidly from 18 to 1°C. During the cooling process, three individuals were removed from culture tanks at 18, 13, 8, 5, 3, and 1°C. Blood samples and tissues were taken from each individual, hematological indices and HSP gene expression in tissues were measured. The red blood cell count, white blood cell count, and hemoglobin concentration decreased significantly (P < 0.05) as temperature decreased. Enzyme activities of plasma alanine transaminase and creatine kinase increased as temperature decreased, whereas aspartic transaminase and γ-glutamyl transpeptidase activities displayed no obvious changes above 1°C and lactate dehydrogenase activity increased first and then decreased. Blood urea nitrogen and uric acid levels were highest at 8°C, and creatinine concentration was highest at 3°C. The concentrations of plasma cortisol, cholesterol, and triglyceride all increased significantly (P < 0.05) as temperature decreased. The serum glucose concentration increased first and then decreased to the initial level. The HSP70 mRNA expression showed various patterns in different tissues, whereas HSP90 mRNA expression showed the same tendency in all tissues. Overall, these results indicate that temperature decreases in the range of 8 to 5°C may induce a stress response in S. maximus and that temperature should be kept above 8°C in the aquaculture setting to avoid damage to the fish.

A new therapeutic effect of simvastatin revealed by functional improvement in muscular dystrophy

Duchenne muscular dystrophy (DMD) is a lethal, degenerative muscle disease with no effective treatment. DMD muscle pathogenesis is characterized by chronic inflammation, oxidative stress, and fibrosis. Statins, cholesterol-lowering drugs, inhibit these deleterious processes in ischemic diseases affecting skeletal muscle, and therefore have potential to improve DMD. However, statins have not been considered for DMD, or other muscular dystrophies, principally because skeletal-muscle-related symptoms are rare, but widely publicized, side effects of these drugs. Here we show positive effects of statins in dystrophic skeletal muscle. Simvastatin dramatically reduced damage and enhanced muscle function in dystrophic (mdx) mice. Long-term simvastatin treatment vastly improved overall muscle health in mdx mice, reducing plasma creatine kinase activity, an established measure of muscle damage, to near-normal levels. This reduction was accompanied by reduced inflammation, more oxidative muscle fibers, and improved strength of the weak diaphragm muscle. Shorter-term treatment protected against muscle fatigue and increased mdx hindlimb muscle force by 40%, a value comparable to current dystrophin gene-based therapies. Increased force correlated with reduced NADPH Oxidase 2 protein expression, the major source of oxidative stress in dystrophic muscle. Finally, in old mdx mice with severe muscle degeneration, simvastatin enhanced diaphragm force and halved fibrosis, a major cause of functional decline in DMD. These improvements were accompanied by autophagy activation, a recent therapeutic target for DMD, and less oxidative stress. Together, our findings highlight that simvastatin substantially improves the overall health and function of dystrophic skeletal muscles and may provide an unexpected, novel therapy for DMD and related neuromuscular diseases.

Plasma chemistry before and after two consecutive days of racing in sled dogs: associations between muscle damage and electrolyte status

Exercising long distance endurance sled dogs display plasma biochemistry changes characterised by elevations in creatine kinase (CK) and aspartate aminotransferase (AST), hypoproteinemia, hypoglobulinemia and decreases in sodium and potassium. The aim of this study was to compare resting to day 2 racing plasma biochemistry and associations between electrolytes and markers of muscle damage in well-conditioned sled dogs during a stage-stop race. Blood samples were obtained from 23 dogs prior to the start and on day 2, immediately after racing. Results showed significant decreases in potassium (day 0 – 4.7±0.3 and day 2 – 4.2±0.3 mEq/l), total protein (day 0 – 6.0±0.3 and day 2 – 5.5±0.4 g/dl) and albumin concentrations (day 0 – 3.9±0.2 and day 2 – 3.6±0.3 g/dl). Increases in AST (day 0 – 24±7 and day 2 – 137±97 U/l) and CK activities (day 0 – 129±39 and day 2 – 2,047±2,021 U/l) were also observed. Plasma sodium concentrations were not significantly different after day 2 of racing (day 0 – 153±5.2 and day 2 – 151±4.1). Alterations in plasma electrolytes, and increases in AST, CK, alanine aminotransferase and urea nitrogen were similar to those observed in long distance endurance sled dogs. A strong negative association was observed between plasma potassium and increases in plasma CK activity on day 2 (R2=0.69). The maintenance of sodium concentrations with a concurrent potassium decline, suggests sodium conservation via the renin-angiotensin-aldosterone pathway as previously shown in endurance sled dogs. The negative correlation between muscle damage and plasma potassium warrants further investigation regarding its relationship to rhabdomyolysis.

Avenanthramide supplementation attenuates eccentric exercise-inflicted blood inflammatory markers in women.

Rigorous exercise is known to generate reactive oxygen species (ROS) and inflict inflammatory response. The present study investigated whether dietary supplementation of avenanthramides (AVA) in oats would increase antioxidant protection and reduce inflammation in humans after an acute bout of eccentric exercise. Young women (age 18-30 years, N = 16) were randomly divided into two groups in a double-blinded fashion, receiving two cookies made of oat flour providing 9.2 mg AVA (AVA) or 0.4 mg AVA (Control, C) each day for 8 weeks. Before and after the dietary regimen each group of subjects ran downhill (DR) on a treadmill at -9% grade for 1 h at a speed to elicit 75% of maximal heart rate. Blood samples were collected at rest, immediately and 24 h post-DR. Before dietary supplementation plasma creatine kinase activity and tumor necrosis factor (TNF)-α concentration were increased immediately after DR (P < 0.05), whereas neutrophil respiratory burst (NRB) was elevated 24 h post-DR (P < 0.05). CK and TNF-α response to DR was abolished during post-supplementation tests in both AVA and C groups, whereas NRB was blunted only in AVA but not in C. Plasma interleukin-6 level and mononuclear cell nuclear factor (NF) κB activity were not affected by DR either before or after dietary supplementation, but were lowered 24 h post-DR in AVA versus C (P < 0.05). Both groups increased plasma total antioxidant activity following 8-week dietary regimen (P < 0.05), whereas only AVA group increased resting plasma glutathione (GSH) concentration (P < 0.05), decreased glutathione disulfide response to DR, and lowered erythrocyte GSH peroxidase activity (P < 0.05). Our data of pre- and post-supplementation difference reflect an interaction between repeated measure effect of eccentric exercise and AVA in diet. Long-term AVA supplementation can attenuate blood inflammation markers, decrease ROS generation and NFkB activation, and increased antioxidant capacity during an eccentric exercise bout.

Effects of pre-slaughter showering and ventilation on stress, meat quality and metabolite concentrations of broilers in summer.

Effects of pre-slaughter showering and ventilation on stress, meat quality and energy metabolism of broilers in summer were investigated. After transport, 84 Arbor Acres broilers were randomly divided into four treatment groups: (i) control group without ventilation and showering (C); (ii) 10 min ventilation without showering (VWS); (iii) 10 min showering without ventilation (SWV); (iv) 5 min showering and then 5 min ventilation (SV). Compared with the control group, plasma lactate dehydrogenase and creatine kinase activities in the other three treatment groups were (P < 0.05) lower; however, the plasma glucose level did not show any significant changes among all the groups. The breast meat in the SV group had significantly (P < 0.05) higher pHu , glycogen content, lower L*, ΔpH, drip loss, cook loss, R-value and lactate content than the control group; however, there was no significant difference in shear force values among all the groups. In conclusion, this study indicated broilers in the SV group showed a lower stress level and greater meat quality, which suggest that showering and ventilation after transportation may be a good measure to relieve stress caused by transport under high temperature and improve the meat quality of broilers.

Creatine kinase isoenzyme activity during and after an ultra-distance (200 km) run.

It is commonly assumed that creatine kinase (CK) activity in plasma is related to the state of an inflammatory response at 24-48 h, and also it has shown biphasic patterns after a marathon run. No information is available on CK isoenzymes after an ultra-marathon run. The purpose of the present study is to examine the CK isoenzymes after a 200 km ultra-marathon run and during the subsequent recovery. Blood samples were obtained during registration 1 2 h before the 200-km race and during the race at 100 km, 150 km and at the end of 200 km, as well as after a 24 h period of recovery. Thirty-two male ultra-distance runners participated in the study. Serum CPK showed a marked increase throughout the race and 24 h recovery period (p < 0.001). Serum CK during the race occurs mostly in the CK-MM isoform and only minutely in the CK-MB isoform and is unchanged in the CK-BB isoform. High-sensitivity C-reactive protein (hs-CRP), oestradiol, AST and ALT increased significantly from the pre-race value at 100 km and a further increase took place by the end of the 200 km run. The results of our study demonstrate a different release pattern of creatine kinase after an ultra-distance (200 km) run compared to the studies of marathon running and intense eccentric exercise, and changes in several biomarkers, indicative of muscle damage during the race, were much more pronounced during the latter half (100–200 km) of the race. However, the increases in plasma concentration of muscle enzymes may reflect not only structural damage, but also their rate of clearance.

감초탕 섭취가 고강도 저항성 운동 후 근부상, 혈중 코티졸, 테스토스테론 및 인슐린 민감도에 미치는 영향

Objectives : The aim of this study was to investigate the effects of licorice supplementation on muscle injury, plasma cortisol, testosterone and insulin sensitivity after high intensity resistance exercise. Methods : The fourteen health college male students were voluntarily participated in this study and were randomly divided into 2 groups: Control group (CON, n=7), Licorice group (LR, n=7). LR group ingested 2 g/time of licorice extract (mixed with 100 ml of water) two times/day for 10 days while the CON group ingested 100 ml of water. All subjects performed a high intensity resistance exercise (half-squat, 8 RM at 80% one-repetition maximum, 5 sets, 1min rest). Blood samples were collect before (-7) and after (0) licorice supplementation, and then 1 day, 2 day and 3 day post exercise. After 10 day treatment, plasma creatine kinase, cortisol, testosterone, glucose, insulin were measured. To determine the insulin sensitivity, HOMA-IR was calculated. Results : Plasma creatine kinase activities were significantly elevated after exercise, but there was not different between two groups. The plasma cortisol and testosterone levels were not significantly different between two groups. Plasma glucose levels were increased at 1 day and 2 day after exercise in the LR comparing with CON group (P<0.05) but plasma insulin levels were significantly lower in comparison with CON. HOMA-IR were significantly lower in the LR than CON group at 0 day to 3 day (P<0.05). Conclusions : The results of the current study suggest that licorice supplementation for 10 days might not attenuate the high-intensity exercise-induce muscle injury but may enhance the whole-body insulin sensitivity.

The effect of high intensity interval training on cardioprotection against ischemia-reperfusion injury in wistar rats.

The aims of the present study were to determine whether short term high intensity interval training (HIIT) could protect the heart against ischemia reperfusion (IR) injury; and if so, to evaluate how long the exercise-associated protection can be lasted. Sixty-three rats were randomly assigned into sedentary (n = 15), sham (n = 7), and exercise groups (n = 41). Rats in the exercise groups performed 5 consecutive days of HIIT on treadmill: 5 min warm up with 50 % VO2max, 6×2 min with 95-105 % VO2max (about 40 to 45 m/min), 5×2 min recovery with 65-75 % VO2max (about 28 to 32 m/min), and 3 min cool down with 50 % VO2max, all at 0 % grade. Animals exposed to an in vivo cardiac IR surgery, performed at days 1, 7, and 14 following the final exercise session. Ischemia-induced arrhythmias, myocardial infarct size (IS), plasma lactate dehydrogenase (LDH) and creatine kinase (CK) activities were measured in all animals. Compared to sedentary rats, exercised animals sustained less IR injury as evidenced by a lower size of infarction and lower levels of LDH and CK at day one and day 7 post exercise. In comparison of sedentary group, IS significantly decreased in EX-IR1 and EX-IR7 groups (50 and 35 %, respectively), but not in EX-IR14 group (19 %). The exercise-induced cardioprotection disappeared 14 days following exercise cessation. There were no significant changes in ischemia-induced arrhythmia between exercised and sedentary rats. The results clearly demonstrate that HIIT protects the heart against myocardial IR injury. This protective effect can be sustained for at least one week following the cessation of the training.

Delta-aminolevulinic acid dehydratase (δALAD) activity in four free-living bird species exposed to different levels of lead under natural conditions

The purposes of this study were: (1) to determine the δALAD activity and δALAD ratio in blood of four free-living bird species (Griffon vulture, Eagle owl, Slender-billed gull and Audouin’s gull); (2) and to investigate the correlations between δALAD activity/ratio and Pb concentrations in blood samples. A decrease was observed in δALAD activity in Griffon vultures and Eagle owls exposed to Pb. In addition, negative relationships were found between δALAD ratio or δALAD activity and Log blood Pb levels in Griffon vultures and Eagle owls, and these relationships were stronger in areas with the highest Pb exposure. We provide equations that may be helpful to estimate δALAD activity and δALAD ratio using blood Pb concentrations. Regarding gull species, δALAD activity found in the present study may be considered the normal activity in Slender-billed gull and Audouin’s gull species, since very low blood Pb concentrations and no correlations were found in these species. Although both δALAD activity and δALAD ratio are sensitive biomarkers of Pb exposure and effect in birds, the use of δALAD ratio may improve the results. Besides, this study provides blood threshold concentrations at which Pb bears effects on δALAD enzyme (5µg/dl in Eagle owl; 8µg/dl in Griffon vulture; and probably >2µg/dl in Slender-billed gull and Audouin’s gull). Our findings show that Eagle owl seems to be more sensitive to δALAD enzymatic inhibition by Pb than Griffon vultures. Eagle owls and Griffon vultures exhibited up to 79% and 94% decrease in δALAD activity when blood Pb concentrations exceeded 19 and 30µg/dl, respectively. Regarding the effects related with δALAD inhibition, significant negative correlations were found between δALAD activity and hematocrit in Eagle owls and Griffon vultures, which may be related to compensatory response associated with a decrease in δALAD activity. In addition, an effect on creatine kinase activity and total proteins in plasma was found in Griffon vultures. The significant negative correlations found between δALAD activity and tGSH in Griffon vulture, and between δALAD activity and Log CAT activity in Eagle owls, may be related to a protective response of antioxidant system against reactive oxygen species (ROS). The negative relationship found between δALAD activity and TBARS levels in Griffon vulture is probably related to an induction of lipid peroxidation by ROS that may be generated by δALA accumulation when δALAD activity is depressed. δALAD activity and δALAD ratio in blood are suggested as important nondestructive biomarkers for Pb exposure and effect for future biomonitoring studies in Griffon vulture and Eagle owl. Further studies are recommended to provide new data on Pb concentrations at which δALAD activity is affected in different wild bird species and to elucidate why different species tolerate Pb in different ways.

The Triterpenoid Betulin Protects against the Neuromuscular Effects of Bothrops jararacussu Snake Venom In Vivo.

We confirmed the ability of the triterpenoid betulin to protect against neurotoxicity caused by Bothrops jararacussu snake venom in vitro in mouse isolated phrenic nerve-diaphragm (PND) preparations and examined its capability of in vivo protection using the rat external popliteal/sciatic nerve-tibialis anterior (EPSTA) preparation. Venom caused complete, irreversible blockade in PND (40 μg/mL), but only partial blockade (~30%) in EPSTA (3.6 mg/kg, i.m.) after 120 min. In PND, preincubation of venom with commercial bothropic antivenom (CBA) attenuated the venom-induced blockade, and, in EPSTA, CBA given i.v. 15 min after venom also attenuated the blockade (by ~70% in both preparations). Preincubation of venom with betulin (200 μg/mL) markedly attenuated the venom-induced blockade in PND; similarly, a single dose of betulin (20 mg, i.p., 15 min after venom) virtually abolished the venom-induced decrease in contractility. Plasma creatine kinase activity was significantly elevated 120 min after venom injection in the EPSTA but was attenuated by CBA and betulin. These results indicate that betulin given i.p. has a similar efficacy as CBA given i.v. in attenuating the neuromuscular effects of B. jararacussu venom in vivo and could be a useful complementary measure to antivenom therapy for treating snakebite.

Influence of production system in local and conventional pig breeds on stress indicators at slaughter, muscle and meat traits and pork eating quality

Sensory quality of pork is a complex phenotype determined by interactions between genetic and environmental factors. This study aimed at describing the respective influences of breed and production system on the development of pork quality. Plasma stress indicators and Longissimus muscle (LM) composition, physicochemical and sensory quality traits were determined in two contrasted breeds – the conventional Large White (LW, n=40) and the French local Basque (B, n=60). Pigs were reared in either a conventional (C; n=20 per breed), alternative (A; sawdust bedding and outdoor area, n=20 per breed) or extensive system (E; free-range, n=20 B). All the pigs from A and C systems were slaughtered at the same slaughterhouse, whereas B pigs from the E system were slaughtered at a local commercial abattoir. Major breed differences were found for almost all traits under study. LM from B pigs exhibited higher lipid, lower water and collagen concentrations, as well as lower collagen thermal solubility (P<0.001). Although plasma stress indicators at slaughter did not differ between breeds, except lower (P<0.05) lactate levels in B pigs, they exhibited higher LM pH1 and pHu values, and lower meat lightness, hue angle, water (drip, thawing and cooking) losses, glycolytic potential and shear force. Sensory analyses highlighted higher redness, marbling, tenderness, juiciness and flavour scores (P<0.01) of meat from B compared with LW pigs. Within both LW and B breeds, compared with C, the A system did not (P>0.05) influence plasma stress indicators, LM chemical composition and physicochemical or sensory traits of pork. In contrast, within the B pigs, the E system affected the meat quality more. Lower plasma cortisol levels (P<0.05), but higher plasma lactate, creatine kinase and lactate dehydrogenase activities, and more skin lesions (P<0.05), indicating higher muscular activity during pre-slaughter handling, were found in pigs produced in the E compared with the C system. E pigs exhibited higher meat pH1 and pHu values and shear force (P<0.01) and exhibited lower lightness, hue angle and drip and thawing losses (P<0.01) compared with the C pigs, whereas LM lipid, protein or collagen concentrations were not affected. Regarding sensory traits, the E system produced redder meat, but did not impact the eating quality of pork. Altogether, this study demonstrates that differences in meat quality between B and LW breeds can be modulated by extensive pig production system.

Effect of a prior bout of preconditioning exercise on muscle damage from downhill walking.

This study investigated whether reduced-duration downhill walking (DW) would confer a protective effect against muscle damage induced by a subsequent bout of longer duration DW performed 1 week or 4 weeks later. Healthy young adults were allocated to a control or one of the preconditioning exercise (PRE-1wk or PRE-4wk) groups (10 men and 4 women per group). PRE-1wk and PRE-4wk groups performed 20-min DW (-28% slope, 5 km/h, 10% body mass added to a backpack) 1 week and 4 weeks before 40-min DW, respectively, and the control group performed 40-min DW only. Maximal voluntary contraction (MVC) knee extension torque, plasma creatine kinase (CK) activity, and muscle soreness (100-mm visual analog scale) were measured before, immediately after, and 24, 48, and 72 h after DW, and the changes in these variables were compared among groups. The control group showed symptoms of muscle damage (e.g., prolonged decrease in MVC: -14% ± 10% at 48 h post-DW) after 40-min DW. Changes in all variables after 40-min DW of PRE-1wk and PRE-4wk groups were 54%-61% smaller (P < 0.05) than the control group, without significant differences between PRE-1wk and PRE-4wk groups for MVC and plasma CK activity. Importantly, changes after the preconditioning exercise (20-min DW) were 67%-69% smaller (P < 0.05) than those after the 40-min DW of the control group. These findings suggest that 20-min DW resulting in minor muscle damage conferred a protective effect against subsequent 40-min DW, and its effect could last for more than 4 weeks.

The effect of transportation of broilers during summer on the expression of heat shock protein 70, postmortem metabolism and meat quality.

The objective of this study was to determine the effects of different transport times on broilers during summer on stress, meat quality, and early postmortem muscle metabolites. Arbor Acres broiler chickens (n = 105) were randomly categorized into 5 treatments: unstressed control, 0.5 h, 1 h, 2 h, and 4 h transport. Each treatment consisted of 3 replicates with 7 birds each. All birds (except the control group) were transported according to a designed protocol. With the extension of transport time, the activities of plasma creatine kinase (CK) and lactate dehydrogenase (LDH) gradually increased. The content of heat shock protein 70 (Hsp70) did not change significantly during 0.5 h transport compared to the control group, but was significantly higher (P < 0.05) at 1 h or more of transport time. Also, transport times of 2 h or more resulted in a death rate of 20%-33% of broilers. We found that the breast meat in the 0.5 h transport group had significantly (P < 0.05) higher L* values, drip loss, cooking loss, AMP/ATP ratio, and phosphorylation of AMP-activated protein kinase (p-AMPK). In addition, pH24h was lower compared to the control group, increasing the likelihood of pale, soft, and exudative (PSE)-like meat. However, no significant variations were found in meat color, drip loss, or cooking loss in other transport groups compared to the control group under the condition of this study. Muscle glycogen content decreased with time of transportation. There were significant correlations among p-AMPK and meat quality (P < 0.05). These results indicate that preslaughter transport during summer may cause severe physiological and biochemical changes of broilers. Further investigations studying the deeper relationship between biological indicators and meat quality according to the similar transport conditions would provide a better understanding of the effect of transport duration on meat quality.

Effects of Coenzyme Q10 on Statin-Induced Myopathy: A Meta-analysis of Randomized Controlled Trials

ObjectiveTo evaluate the efficacy of coenzyme Q10 (CoQ10) supplementation on statin-induced myopathy. Participants and MethodsWe searched the MEDLINE, Cochrane Library, Scopus, and EMBASE databases (November 1, 1987, to May 1, 2014) to identify randomized controlled trials investigating the impact of CoQ10 on muscle pain and plasma creatine kinase (CK) activity as 2 measures of statin-induced myalgia. Two independent reviewers extracted data on study characteristics, methods, and outcomes. ResultsWe included 6 studies with 302 patients receiving statin therapy: 5 studies with 226 participants evaluated the effect of CoQ10 supplementation on plasma CK activity, and 5 studies (4 used in the CK analysis and 1 other study) with 253 participants were included to assess the effect of CoQ10 supplementation on muscle pain. Compared with the control group, plasma CK activity was increased after CoQ10 supplementation, but this change was not significant (mean difference, 11.69 U/L [to convert to μkat/L, multiply by 0.0167]; 95% CI, –14.25 to 37.63 U/L; P=.38). Likewise, CoQ10 supplementation had no significant effect on muscle pain despite a trend toward a decrease (standardized mean difference, –0.53; 95% CI, –1.33 to 0.28; P=.20). No dose-effect association between changes in plasma CK activity (slope, –0.001; 95% CI, –0.004 to 0.001; P=.33) or in the indices of muscle pain (slope, 0.002; 95% CI, –0.005 to 0.010; P=.67) and administered doses of CoQ10 were observed. ConclusionThe results of this meta-analysis of available randomized controlled trials do not suggest any significant benefit of CoQ10 supplementation in improving statin-induced myopathy. Larger, well-designed trials are necessary to confirm the findings from this meta-analysis.

Changes in CEBPB expression in circulating leukocytes following eccentric elbow-flexion exercise.

In mouse models, CCAAT enhancer-binding protein beta (CEBPB) is necessary for M2 macrophage-mediated regeneration after muscle injury. In humans, CEBPB expression in blood was strongly associated with muscle strength. In this study we aimed to test whether CEBPB expression in blood in people is increased 2 days after exercise designed to induce muscle damage and subsequent repair. Sixteen healthy male volunteers undertook elbow flexor exercises designed to induce acute muscle micro-damage. Peripheral blood samples were collected at baseline and days 1, 2, 4 and 7 following exercise. Expression of CEBPB and related genes were analysed by qRT-PCR. Extent of muscle damage was determined by decline in maximal voluntary isometric torque and by plasma creatine kinase activity. Nine subjects had peak (day 4) creatine kinase activity exceeding 10,000 U/l. In this subgroup, CEBPB expression was elevated from baseline to 2 days post exercise (paired-samples t (1,8) = 3.72, p = 0.006). Related expression and selected cytokine changes after exercise did not reach significance. Muscle-damaging exercise in humans can be followed by induction of CEBPB transcript expression in peripheral blood. Associations between CEBPB expression in blood and muscle strength may be consistent with the CEBPB-dependent muscle repair process.Electronic supplementary materialThe online version of this article (doi:10.1007/s12576-014-0350-7) contains supplementary material, which is available to authorized users.

Acute effects of static active or dynamic active stretching on eccentric-exercise-induced hamstring muscle damage.

To examine whether an acute bout of active or dynamic hamstring-stretching exercises would reduce the amount of muscle damage observed after a strenuous eccentric task and to determine whether the stretching protocols elicit similar responses. A randomized controlled clinical trial. Thirty-six young male students performed 5 min of jogging as a warm-up and were allocated to 1 of 3 groups: 3 min of static active stretching (SAS), 3 min of dynamic active stretching (DAS), or control (CON). All subjects performed eccentric exercise immediately after stretching. Heart rate, core temperature, maximal voluntary isometric contraction, passive hip flexion, passive hamstring stiffness (PHS), plasma creatine kinase activity, and myoglobin were recorded at prestretching, at poststretching, and every day after the eccentric exercises for 5 d. After stretching, the change in hip flexion was significantly higher in the SAS (5°) and DAS (10.8°) groups than in the CON (-4.1°) group. The change in PHS was significantly higher in the DAS (5.6%) group than in the CON (-5.7%) and SAS (-6.7%) groups. Furthermore, changes in muscle-damage markers were smaller in the SAS group than in the DAS and CON groups. Prior active stretching could be useful for attenuating the symptoms of muscle damage after eccentric exercise. SAS is recommended over DAS as a stretching protocol in terms of strength, hamstring range of motion, and damage markers.

Time course of central and peripheral alterations after isometric neuromuscular electrical stimulation-induced muscle damage.

Isometric contractions induced by neuromuscular electrostimulation (NMES) have been shown to result in a prolonged force decrease but the time course of the potential central and peripheral factors have never been investigated. This study examined the specific time course of central and peripheral factors after isometric NMES-induced muscle damage. Twenty-five young healthy men were subjected to an NMES exercise consisting of 40 contractions for both legs. Changes in maximal voluntary contraction force of the knee extensors (MVC), peak evoked force during double stimulations at 10 Hz (Db10) and 100 Hz (Db100), its ratio (10∶100), voluntary activation, muscle soreness and plasma creatine kinase activity were assessed before, immediately after and throughout four days after NMES session. Changes in knee extensors volume and T2 relaxation time were also assessed at two (D2) and four (D4) days post-exercise. MVC decreased by 29% immediately after NMES session and was still 19% lower than the baseline value at D4. The decrease in Db10 was higher than in Db100 immediately and one day post-exercise resulting in a decrease (−12%) in the 10∶100 ratio. On the contrary, voluntary activation significantly decreased at D2 (−5%) and was still depressed at D4 (−5%). Muscle soreness and plasma creatine kinase activity increased after NMES and peaked at D2 and D4, respectively. T2 was also increased at D2 (6%) and D4 (9%). Additionally, changes in MVC and peripheral factors (e.g., Db100) were correlated on the full recovery period, while a significant correlation was found between changes in MVC and VA only from D2 to D4. The decrease in MVC recorded immediately after the NMES session was mainly due to peripheral changes while both central and peripheral contributions were involved in the prolonged force reduction. Interestingly, the chronological events differ from what has been reported so far for voluntary exercise-induced muscle damage.

Voriconazole Disposition After Single and Multiple, Oral Doses in Healthy, Adult Red-tailed Hawks ( Buteo jamaicensis ).

Voriconazole is effective for treatment of aspergillosis, a common disease in captive red-tailed hawks ( Buteo jamaicensis ). To determine the disposition and safety of voriconazole after single and multiple, oral doses, 12 adult red-tailed hawks were studied in 2 phases. In phase 1, each bird received a single dose of voriconazole solution (10 mg/kg) by gavage. Blood samples were collected at 0, 0.5, 1, 3, 6, 9, 12, 16, 24, and 36 hours after treatment. In phase 2, each of 8 birds received voriconazole oral solution at 10 mg/kg PO q12h for 14 days. Plasma samples were collected on days 0, 5, and 10 and after the final dose and were processed as in phase 1. Plasma samples were submitted for analysis of voriconazole levels by high-performance liquid chromatography and ultraviolet spectrophotometry and for measurement of selected plasma biochemical parameters. After single dosing, voriconazole concentrations reached a (mean ± SD) peak (Cmax) of 4.7 ± 1.3 μg/mL at 2.0 ± 1.2 hours. The disappearance half-life (t1/2) was 2.8 ± 0.7 hours, and the mean residence time (MRT) was 4.6 ± 0.9 hours. After the last dose at 14 days, the mean Cmax of voriconazole was 4.5 ± 2.7 μg/mL at 2.4 ± 1.1 hours. The t1/2 was 2.1 ± 0.8 hours, and the MRT was 3.5 ± 1.1 hours. Although concentrations of several plasma biochemical parameters were significantly different at study end compared with prestudy concentrations, only plasma creatine kinase activity was outside the reference range. No adverse reactions were observed in any of the birds. After both single and multiple dosing at 10 mg/kg, voriconazole concentrations exceeded the minimum inhibitory concentration to inhibit 90% (MIC90) of Aspergillus species (1 μg/mL) by at least fourfold and remained above the MIC90 for 8.8 ± 1.1 hours after single dosing versus 6.5 ± 1.5 hours after multiple dosing (P = .003). This difference suggests that more frequent dosing (eg, up to q8h) may be necessary to maintain target concentrations during prolonged therapy.