Increase In Plasma Creatine Kinase Research Articles

Muscle Fatigue Is Attenuated When Applying Intermittent Compared With Continuous Blood Flow Restriction During Endurance Cycling.

The aim of this study was to identify a blood-flow-restriction (BFR) endurance exercise protocol that maximizes metabolic strain and minimizes muscle fatigue. Twelve healthy participants accomplished 5 different interval cycling endurance exercises (2-min work, 1-min rest) in a randomized order: (1)control, low intensity with unrestricted blood flow (CON30); (2)low intensity with intermittent BFR (i-BFR30, ∼150mm Hg); (3)low intensity with continuous BFR (c-BFR, ∼100mm Hg); (4)unloaded cycling with i-BFR0 (∼150 mm Hg); and (5)high intensity (HI) with unrestricted blood flow. Force production, creatine kinase activity, antioxidant markers, blood pH, and potassium (K+) were measured in a range of 5 minutes before and after each cycling exercise protocol. HI showed the highest reduction (Δ = -0.26 [0.05], d = 5.6) on blood pH. Delta pH for c-BRF30 (Δ = -0.02 [0.03], d = 0.8) and ΔpH for i-BRF30 (Δ = -0.04 [0.03], d = 1.6) were different from each other, and both were higher compared with CON30 (Δ = 0.03 [0.03]). There was significant before-to-after force loss following HI (Δ = 55 [40]N·m-1, d = 1.5) and c-BFR30 (Δ = 27 [21]N·m-1, d = 0.7) protocols only, which were accompanied by significant increases in K+ (HI: Δ = 0.94 [0.65]mmol·L-1, d = 1.8; c-BFR30: Δ = 0.72 [0.85]mmol·L-1, d = 1.2). Moreover, all BFR conditions elicited slight increases in plasma creatine kinase, but not for HI and CON30. Glutathione changes from before to after were significant for all BFR conditions and HI, but not for CON30. The attenuation in fatigue-induced reductions in maximal force suggests that i-BFR exercise could be preferable to c-BFR in improving exercise capacity, with considerably less biologic stress elicited from HI exercises.

The Effects of Leucine-Enriched Branched-Chain Amino Acid Supplementation on Recovery After High-Intensity Resistance Exercise.

Of the 3 branched-chain amino acids (BCAA), leucine has arguably received the most attribution for the role of BCAA supplementation in alleviating symptoms of exercise-induced muscle damage and facilitation of acute performance recovery. To examine whether enrichment of a standard BCAA supplement with additional leucine or a standalone leucine (LEU) supplement differentially affects exercise-induced muscle damage and performance recovery compared with a standard BCAA supplement. A total of 22 recreationally active male and female subjects were recruited and assigned to consume a BCAA, leucine-enriched BCAA (LBCAA), or LEU supplement for 11 d. On the eighth day, subjects performed eccentric-based resistance exercise (ECRE). Lower-body mean average and peak power, plasma creatine kinase, soreness, and pain threshold were measured before and 24, 48, and 72h after ECRE. LEU showed decreased mean average power (P = .02) and mean peak power (P = .01) from baseline to 48h post-ECRE, whereas LBCAA and BCAA only trended toward a reduction at 24 hours post-ECRE. At 48h post-ECRE, BCAA showed greater recovery of mean peak power than LEU (P = .04). At 24h post-ECRE, LEU demonstrated a greater increase in plasma creatine kinase from baseline than BCAA (P = .04). Area under the curve for creatine kinase was greater in LEU than BCAA (P = .02), whereas BCAA and LBCAA did not differ. Only LEU demonstrated increased soreness during rest and under muscular tension at 24 and 48 h post-ECRE (P < .05). LBCAA failed to afford any advantages over a standard BCAA supplement for postexercise muscle recovery, whereas a LEU supplement was comparatively ineffective.

Isolation and Functional Characterization of an Acidic Myotoxic Phospholipase A₂ from Colombian Bothrops asper Venom.

Myotoxic phospholipases A2 (PLA2) are responsible for many clinical manifestations in envenomation by Bothrops snakes. A new myotoxic acidic Asp49 PLA2 (BaCol PLA2) was isolated from Colombian Bothrops asper venom using reverse-phase high performance liquid chromatography (RP-HPLC). BaCol PLA2 had a molecular mass of 14,180.69 Da (by mass spectrometry) and an isoelectric point of 4.4. The complete amino acid sequence was obtained by cDNA cloning (GenBank accession No. MF319968) and revealed a mature product of 124 amino acids with Asp at position 49. BaCol PLA2 showed structural homology with other acidic PLA2 isolated from Bothrops venoms, including a non-myotoxic PLA2 from Costa Rican B. asper. In vitro studies showed cell membrane damage without exposure of phosphatidylserine, an early apoptosis hallmark. BaCol PLA2 had high indirect hemolytic activity and moderate anticoagulant action. In mice, BaCol PLA2 caused marked edema and myotoxicity, the latter seen as an increase in plasma creatine kinase and histological damage to gastrocnemius muscle fibers that included vacuolization and hyalinization necrosis of the sarcoplasm.

Angiotensin IV protects cardiac reperfusion injury by inhibiting apoptosis and inflammation via AT4R in rats

Angiotensin IV (Ang IV) is formed by aminopeptidase N from Ang III by removing the first N-terminal amino acid. Previously, we reported that Ang III has some cardioprotective effects against global ischemia in Langendorff heart. However, it is not clear whether Ang IV has cardioprotective effects. The aim of the present study was to evaluate the effect of Ang IV on myocardial ischemia-reperfusion (I/R) injury in rats. Before ischemia, male Sprague-Dawley rats received Ang IV (1mg/kg/day) for 3 days. Anesthetized rats were subjected to 45min of ischemia by ligation of left anterior descending coronary artery followed by reperfusion and then, sacrificed 1 day or 1 week after reperfusion. Plasma creatine kinase (CK) and lactate dehydrogenase (LDH) concentrations, and infarct size were measured. Quantitative analysis of apoptotic and inflammatory proteins in ventricles were performed using Western blotting. Pretreatment with Ang IV attenuated I/R-induced increases in plasma CK and LDH levels, and infarct size, which were blunted by Ang IV receptor (AT4R) antagonist and but not by antagonist for AT1R, AT2R, or Mas receptor. I/R increased Bax, caspase-3 and caspase-9 protein levels, and decreased Bcl-2 protein level in ventricles, which were blunted by Ang IV. I/R-induced increases in TNF-α, MMP-9, and VCAM-1 protein levels in ventricles were also blunted by Ang IV. Ang IV increased the phosphorylation of Akt and mTOR. These effects were attenuated by co-treatment with AT4R antagonist or inhibitors of downstream signaling pathway. Myocardial dysfunction after reperfusion was improved by Ang IV. These results suggest that Ang IV has cardioprotective effect against I/R injury by inhibiting apoptosis via AT4R and PI3K-Akt-mTOR pathway.

Occurrence of sulfated fucose branches in fucosylated chondroitin sulfate are essential for the polysaccharide effect preventing muscle damage induced by toxins and crude venom from Bothrops jararacussu snake.

Snake envenoming is an important public health problem around the world, particularly in tropics. Beyond deaths, morbidity induced by snake venoms, such as myotoxicity, is of pivotal consequence to population. Bothrops jararacussu is the main venomous snake in southeast region of Brazil, and particularly presents strong myotoxic effect. The only available therapy, antibothropic antivenom, poorly affects venom-induced myotoxicity. The aim of this study is to assess the ability of fucosylated chondroitin sulfate (fucCS), a glycosaminoglycan with anticoagulant and antithrombotic properties, and its derivatives to inhibit toxic activities of B. jararacussu crude venom and its isolated toxins, named bothropstoxins (BthTX-I and BthTX-II). The in vitro myotoxic activities induced by crude venom, by BthTX-I alone and by toxins together were abolished by fucCS. Carboxyl reduction (fucCS-CR) kept this ability whereas defucosilation (defucCS) abrogates myoprotection. We observed the same pattern in the response of these polysaccharides in antagonizing the increase in plasma creatine kinase (CK) levels, the reduction of skeletal muscle CK content and the rise of myeloperoxidase (MPO) activity induced by crude venom and isolated toxins. FucCS inhibited edematogenic activity and partially prevented the reduction of total leukocytes in blood when pre-incubated with crude venom. Furthermore, the venom procoagulant effect was completely antagonized by increasing concentrations of fucCS, although this polyanion could stop neither the tail bleeding nor the skin hemorrhage induced by Bothrops jararaca venom. The B. jararacussu phospholipase, hyaluronidase, proteolytic and collagenase activities were inhibited in vitro. The results suggest that fucCS could be able to interact with both toxins, and it is able to inhibit BthTX-II phospholipase activity. Light microscopy of extensor digitorum longus muscle (EDL) muscle showed myoprotection by fucCS, once necrotic areas, edema and inflammatory cells were all decreased as compared to venom injection alone. Altogether, data show that fucCS was able to inhibit myotoxicity and inflammation induced by B. jararacussu venom and its phospholipase toxins, BthTX-I and BthTX-II. Thus, fucosylated chondroitin sulfate is a new polyanion with potential to be used as an adjuvant in the treatment of snakebites in the future.

Evaluation of plasma muscle enzyme activity as an indicator of lesion characteristics and prognosis in horses undergoing celiotomy for acute gastrointestinal pain.

BackgroundIn horses undergoing celiotomy for acute gastrointestinal pain, identification of variables correlating with lesion severity and location, and survival provide veterinarians and owners with information that aids in making informed decisions regarding appropriate treatment. Muscle enzyme activity is often increased in horses undergoing celiotomy for acute gastrointestinal pain and it is not known if muscle enzyme activity increase is specific to lesion type or impacts prognosis for survival. The objective of this study was to evaluate the relationship of pre-operative increase in muscle enzyme activities with intestinal lesion characteristics, specifically lesion location (large versus small intestine) and whether it was strangulating versus nonstrangulating, and case survival in horses undergoing celiotomy for acute gastrointestinal pain.MethodsRecords of 241 horses undergoing exploratory laparotomy for colic were reviewed retrospectively. Evaluation of preoperative plasma aspartate aminotransferase (AST), creatine kinase (CK), sorbitol dehydrogenase (SDH), and gamma-glutamyltransferase (GGT) activities, fibrinogen and glucose concentrations, and hematocrit (HCT) and their association with gastrointestinal lesion characteristics and survival was performed.ResultsPre-operative increase in plasma CK and AST activity, and HCT and decrease in plasma bilirubin concentration were significantly associated with presence of lesions resulting in intestinal ischemia. Increase in plasma CK activity and HCT were significantly associated with a decreased probability of survival to hospital discharge. Plasma GGT and SDH activity, and glucose and fibrinogen concentration were not significantly associated with survival or severity of disease in multivariate analysis.ConclusionsPlasma muscle enyzme activity may be useful as a prognostic indicator in equine colic cases. Given that increases in plasma CK and AST activity were significantly associated with nonsurvival and the presence of intestinal ischemia, preoperative increase in these enzyme activities could assist in identification of disease severity and prognosis of horses undergoing celiotomy for acute gastrointestinal pain. Further study is indicated to elucidate the etiology of increased muscle enzyme activity in horses with surgical colic disease observed in this preliminary study.

Muscle fatigue experienced during maximal eccentric exercise is predictive of the plasma creatine kinase (CK) response

Unaccustomed eccentric exercise may cause skeletal muscle damage with an increase in plasma creatine kinase (CK) activity. Although the wide variability among individuals in CK response to standardized lengthening contractions has been well described, the reasons underlying this phenomenon have not yet been understood. Therefore, this study investigated a possible correlation of the changes in muscle damage indirect markers after an eccentric exercise with the decline in muscle performance during the exercise. Twenty-seven healthy untrained male subjects performed three sets of 30 maximal isokinetic eccentric contractions of the knee extensors. The muscular work was recorded using an isokinetic dynamometer to assess muscle fatigue by means of various fatigue indices. Plasma CK activity, muscle soreness, and stiffness were measured before (pre) and one day after (post) exercise. The eccentric exercise bout induced significant changes of the three muscle damage indirect markers. Large inter-subject variability was observed for all criteria measured. More interestingly, the log (CK(post) /CK(pre)) and muscle stiffness appeared to be closely correlated with the relative work decrease (r = 0.84, r(2) = 0.70 and r = 0.75, r(2) = 0.56, respectively). This is the first study to propose that the muscle fatigue profile during maximal eccentric protocol could predict the magnitude of the symptoms associated with muscle damage in humans.

Mass spectrometric detection of candidate protein biomarkers of cancer cachexia in human urine

Increased membrane permeability and myofibrillar protein breakdown are established features of cancer cachexia. Proteins released from cachectic muscle may be excreted in urine to act as biomarkers of the cachectic process. One-dimensional SDS polyacrylamide gel electrophoresis followed by matrix-assisted laser desorption/ionisation or liquid chromatography tandem mass spectrometry was used to compare the protein content of urine from cachectic (>10% weight loss) (n=8) and weight-stable (n=8) gastro-oesophageal cancer patients and healthy controls (n=8). Plasma creatine kinase concentration was used as a marker of gross muscle breakdown. The number of protein species identified in cachectic samples (median 42; range 28-61; total 199) was greater than that identified in weight-stable cancer (median 15; range 9-28; total 79) and control samples (median 12.5; range 5-18; total 49) (P<0.001). Many of the proteins identified have not been reported previously in the urine of cancer patients. Proteins identified specifically in cachectic samples included muscle (myosin species), cytoskeletal (alpha-spectrin; nischarin) and microtubule-associated proteins (microtubule-actin crosslinking factor; microtubule-associated protein-1B; bullous pemphigoid antigen 1), whereas immunoglobulin kappa-light chain and zinc alpha-2 glycoprotein appeared to represent markers of cancer. The presence of myosin in urine (without an increase in plasma creatine kinase) is consistent with a specific loss of myosin as part of the cachectic process. Urinary proteomics using mass spectrometry can identify muscle-specific and non-muscle-specific candidate biomarkers of cancer cachexia.

Longitudinal study of the effects of chronic hypothyroidism on skeletal muscle in dogs

To study the effects of experimentally induced hypothyroidism on skeletal muscle and characterize any observed myopathic abnormalities in dogs. 9 female, adult mixed-breed dogs; 6 with hypothyroidism induced with irradiation with 131 iodine and 3 untreated control dogs. Clinical examinations were performed monthly. Electromyographic examinations; measurement of plasma creatine kinase, alanine aminotransferase, aspartate aminotransferase, lactate, and lactate dehydrogenase isoenzyme activities; and skeletal muscle morphologic-morphometric examinations were performed prior to and every 6 months for 18 months after induction of hypothyroidism. Baseline, 6-month, and 18-month assessments of plasma, urine, and skeletal muscle carnitine concentrations were also performed. Hypothyroid dogs developed electromyographic and morphologic evidence of myopathy by 6 months after treatment, which persisted throughout the study, although these changes were subclinical at all times. Hypothyroid myopathy was associated with significant increases in plasma creatine kinase, aspartate aminotransferase, and lactate dehydrogenase 5 isoenzyme activities and was characterized by nemaline rod inclusions, substantial and progressive predominance of type I myofibers, decrease in mean type II fiber area, subsarcolemmal accumulations of abnormal mitochondria, and myofiber degeneration. Chronic hypothyroidism was associated with substantial depletion in skeletal muscle free carnitine. Chronic, experimentally induced hypothyroidism resulted in substantial but subclinical phenotypic myopathic changes indicative of altered muscle energy metabolism and depletion of skeletal muscle carnitine. These abnormalities may contribute to nonspecific clinical signs, such as lethargy and exercise intolerance, often reported in hypothyroid dogs.

Propofol Infusion Syndrome

Propofol (2, 6-diisopropylphenol) is a potent intravenous hypnotic agent that is widely used in adults and children for sedation and the induction and maintenance of anaesthesia. Propofol has gained popularity for its rapid onset and rapid recovery even after prolonged use, and for the neuroprotection conferred. However, a review of the literature reveals multiple instances in which prolonged propofol administration (>48 hours) at high doses (>4 mg/kg/h) may cause a rare, but frequently fatal complication known as propofol infusion syndrome (PRIS). PRIS is characterized by metabolic acidosis, rhabdomyolysis of both skeletal and cardiac muscle, arrhythmias (bradycardia, atrial fibrillation, ventricular and supraventricular tachycardia, bundle branch block and asystole), myocardial failure, renal failure, hepatomegaly and death. PRIS has been described as an 'all or none' syndrome with sudden onset and probable death. The literature does not provide evidence of degrees of symptoms, nor of mildness or severity of signs in the clinical course of the syndrome. Recently, a fatal case of PRIS at a low infusion rate (1.9-2.6 mg/kg/h) has been reported. Common laboratory and instrumental findings in PRIS are myoglobinuria, downsloping ST-segment elevation, an increase in plasma creatine kinase, troponin I, potassium, creatinine, azotaemia, malonylcarnitine and C5-acylcarnitine, whereas in the mitochondrial respiratory electron transport chain, the activity of complex IV and cytochrome oxidase ratio is reduced. Propofol should be used with caution for sedation in critically ill children and adults, as well as for long-term anesthesia in otherwise healthy patients, and doses exceeding 4-5 mg/kg/h for long periods (>48 h) should be avoided. If PRIS is suspected, propofol must be stopped immediately and cardiocirculatory stabilization and correction of metabolic acidosis initiated. So, PRIS must be kept in mind as a rare, but highly lethal, complication of propofol use, not necessarily confined to its prolonged use. Furthermore, the safe dosage of propofol may need re-evaluation, and new studies are needed.

Curcumin Enhances Performance Recovery After Exerciseinduced Muscle Damage

Unaccustomed exercise with a large eccentric component produces the greatest muscle fiber damage, inflammation, delayed-onset muscle soreness (DOMS) and functional deficits. Curcumin (extract of the Indian spice, turmeric) has potent anti-inflammatory activity in a variety of inflammation models, but has not been evaluated with respect to exercise-induced muscle damage. It is possible that the anti-inflammatory activity of curcumin could hasten recovery of performance due to an attenuation of the primary and especially secondary inflammation associated with delayed regeneration of muscle fibers, soreness, and CNS fatigue. PURPOSE 1) to develop a mouse model of performance recovery following exercise-induced muscle damage and 2) to determine the effects of curcumin on performance recovery in this model. METHODS In EXP 1, treadmill run times to fatigue (36m/min, 8% grade) were performed at 24, 48, 72 & 96 h after an uphill (UP) or downhill (DWN) run in male mice. DWN running was 150 min starting at 16m/min, −5% grade with increments every 5 min to 22m/min, −14% grade. UP running was the same, but grade was increased from 5% to 14%. Separate groups of mice were sacrificed at 24, 48 and 96 h after UP and DWN for collection of blood, muscle (soleus), and selected brain regions. Creatine kinase (CK) was measured in blood and inflammatory cytokines (IL-1β, IL-6, and TNF-α) were measured in muscle and brain. Exp 2 evaluated the effect of curcumin on performance recovery at 48 and 72 h after UP and DWN. Mice were fed curcumin (10 mg) once daily in a highly palatable food pellet (410 mg; bacon flavor) for 3 d prior to UP or DWN running. RESULTS In EXP 1, treadmill run time to fatigue was suppressed in DWN vs Up by over 50% for up to 72 h following the initial run. DWN was also associated with an increase in plasma CK at 24 and 48 h, and inflammatory cytokines in muscle (IL-6 & IL-1β) and brain (IL-1β only in cortex & cerebellum) at 24h. In EXP 2, curcumin feedings attenuated the reduction in run time to fatigue at 48 and 72 h in DWN, with no effect in UP. CONCLUSIONS In this model, recovery of endurance capacity takes up to 72 h following downhill running, which is associated with an increase in plasma CK, and muscle and brain inflammatory cytokines. Ingestion of Curcumin (anti-inflammatory herbal supplement) for 3 d prior to muscle-damaging exercise hastens recovery of endurance performance, but the extent to which this is due to a reduction in the inflammatory response (in muscle and/or CNS) awaits further research. Funded by the DOD, Natick Soldier Center, Grant # DAAD 16-02-C-0015.

The effect of creatine supplementation upon inflammatory and muscle soreness markers after a 30km race

We have evaluated the effect of a creatine supplementation protocol upon inflammatory and muscle soreness markers: creatine kinase (CK), lactate dehydrogenase (LDH), prostaglandin E 2 (PGE 2) and tumor necrosis factor-alpha (TNF-α) after running 30km. Runners with previously experience in running marathons, with their personal best between 2.5–3h were supplemented for 5 days prior to the 30km race with 4 doses of 5g of creatine and 15g of maltodextrine per day while the control group received the same amount of maltodextrine. Pre-race blood samples were collected immediately before running the 30km, and 24h after the end of the test (the post-race samples). After the test, athletes from the control group presented an increase in plasma CK (4.4-fold), LDH (43%), PGE 2 6.6-fold) and TNF-α (2.34-fold) concentrations, indicating a high level of cell injury and inflammation. Creatine supplementation attenuated the changes observed for CK (by 19%), PGE 2 and TNF-α (by 60.9% and 33.7%, respectively, p<0.05) and abolished the increase in LDH plasma concentration observed after running 30km, The athletes did not present any side effects such as cramping, dehydration or diarrhea, neither during the period of supplementation, nor during the 30km race. All the athletes finished the race in a time equivalent to their personal best ± 5.8%. These results indicate that creatine supplementation reduced cell damage and inflammation after an exhaustive intense race.

Effect of perimuscular injection of Bothrops jararacussu venom on plasma creatine kinase levels in mice: influence of dose and volume.

The effect of dose and volume of a perimuscular injection of Bothrops jararacussu venom on myonecrosis of skeletal muscle was studied in mice. An increase of the venom dose (0.25 to 2.0 micro g/g) at a given volume (50 micro l) resulted in an increase in plasma creatine kinase (CK) levels 2 h after injection. Plasma CK activity increased from the basal level of 129.27 +/- 11.83 (N = 20) to 2392.80 +/- 709.43 IU/l (N = 4) for the 1.0 micro g/g dose. Histological analysis of extensor digitorum longus muscle 4 h after injection showed lesion of peripheral muscle fibers, disorganization of the bundles or the complete degeneration of muscle fibers. These lesions were more extensive when higher doses were injected. Furthermore, an increase in volume (12.5 to 100 micro l) by dilution of a given dose (0.5 micro g/g) also increased plasma CK levels from 482.31 +/- 122.79 to 919.07 +/- 133.33 IU/l (N = 4), respectively. These results indicate that care should be taken to standardize volumes and sites of venom injections.

Effect of suramin on myotoxicity of some crotalid snake venoms

We investigated the protective effect of suramin, an enzyme inhibitor and an uncoupler of G protein from receptors, on the myotoxic activity in mice of different crotalid snake venoms (A.c. laticinctus, C.v. viridis, C.d. terrificus, B. jararacussu, B. moojeni, B. alternatus, B. jararaca, L. muta). Myotoxicity was evaluated in vivo by injecting im the venoms (0.5 or 1.0 mg/kg) dissolved in physiological saline solution (0.1 ml) and measuring plasma creatine kinase (CK) activity. Two experimental approaches were used in mice (N = 5 for each group). In protocol A, 1 mg of each venom was incubated with 1.0 mg suramin (15 min, 37 degrees C, in vitro), and then injected im into the mice at a dose of 1.0 mg/kg (in vivo). In protocol B, venoms, 1.0 mg/kg, were injected im 15 min prior to suramin (1.0 mg/kg, iv). Before and 2 h after the im injection blood was collected by orbital puncture. Plasma was separated and stored at 4 degrees C for determination of CK activity using a diagnostic kit from Sigma. Preincubation of some venoms (C.v. viridis, A.c. laticinctus, C.d. terrificus and B. jararacussu) with suramin reduced (37-76%) the increase in plasma CK, except for B. alternatus, B. jararaca or L. muta venoms. Injection of suramin after the venom partially protected (34-51%) against the myotoxicity of B. jararacussu, A.c. laticinctus and C.d. terrificus venom, and did not protect against C.v. viridis, L. muta, B. moojeni, B. alternatus or B. jararaca venoms. These results show that suramin has an antimyotoxic effect against some, but not all the North and South American crotalid snake venoms studied here.

Effect of heparin and antivenom on skeletal muscle damage produced by Bothrops jararacussu venom.

We examined the effect of treatment with heparin and polyvalent antivenom on mice muscle Extensor digitorum longus (EDL) regeneration, after damage induced by injection of Bothrops jararacussu crude venom over the muscle of the right posterior limb. The mice were separated into groups and each group received treatment, by intravenous route with either high molecular weight heparin (H), low molecular weight heparin (LMWH), polyvalent antivenom (PAV) or with the combination of PAV plus H or PAV plus LMWH at 15 minutes and 4 hours after the injection of the venom. Myotoxicity was measured by the increase in plasma creatine kinase (CK) activity at two hours after the injection of the venom. The histological changes in EDL at 1, 3, 7 and 21 days after the injection of the venom were analyzed by light microscopy. In each group the normal and regenerated muscle fibers were quantified using Scion Image computer program. We also evaluated in vitro, the influence of these substances in the proteolytic and phospholipase activities of the venom. Heparins decreased the proteolytic activity of the venom but did not affect its phospholipase activity. However the PAV antagonized both activities. PAV and its combinations showed antimyotoxic activity, according to the magnitude of CK plasma levels. At 21 days the regeneration was observed in all animals, also in those that received only the venom. All treatments, except LMWH, promote a significant increase in the number of muscle fibers.

Rôle de la monoxyde d'azote synthase-III et du guanosine 3':5'-monophosphate cyclique dans la protection exercée par le monoxyde d'azote lors d'une ischémie-reperfusion hépatique

Nitric oxide (NO) exerts cytoprotective effects against hepatic ischemia-reperfusion damage. This study was designed to evaluate which isoform of NO synthase (NOS) is implicated in the generation of cytoprotective NO and to investigate whether NO effects are mediated by cyclic GMP (cGMP). After partial ischemia for 45 min, liver damage was estimated by the release into plasma of cytolytic enzymes. Ischemia-reperfusion induced marked increases in plasma creatine kinase and lactate dehydrogenase after 1 h of reperfusion and of aminotransferases after 6 h of reperfusion. The pretreatment of ischemied rats with 8-bromo-cGMP (16 mg/kg iv 30 min before ischemia) or with L-arginine (the endogenous precursor of NO, 100 mg/kg iv) significantly diminished the ischemia-reperfusion-induced release of all these enzymes. This demonstrates that cGMP possesses hepatoprotective properties. By immunohistochemistry, we observed, after 6 h of reperfusion, an increase in endothelial NOS-III immunoreactivity, particularly in the small arteries and sinusoids. This NOS-III accumulation in endothelial cells could protect the liver against ischemia-reperfusion by the local generation of NO probably via cGMP.

Ability of wedelolactone, heparin, and para-bromophenacyl bromide to antagonize the myotoxic effects of two crotaline venoms and their PLA 2 myotoxins

We examined the ability of wedelolactone, heparin and para-bromophenacyl bromide to antagonize the myotoxic activity in mice of venoms from Crotalus viridis viridis and Agkistrodon contortrix laticinctus and two phospholipase A 2 myotoxins, CVV myotoxin and ACL myotoxin, isolated from them. Myotoxicity was measured by the increase in plasma creatine kinase (CK) activity at two hours and histological changes in extensor digitorum longus muscle (EDL) at three hours after injection of the test solution. Both heparin and wedelolactone independently reduced the myotoxic effect of both crude venoms and both myotoxins, but wedelolactone was more effective. Wedelolactone plus heparin reduced the myotoxic effect of CVV myotoxin more than either antagonist alone. The PLA 2 inhibitor, para-bromophenacyl bromide ( pBPB), reduced the myotoxic effect of both myotoxins more than either wedelolactone or heparin. On the other hand, the myotoxic effect of polylysine was not reduced by either wedelolactone or para-bromophenacyl bromide, but it was reduced by heparin. These results indicate that wedelolactone, para-bromophenacyl bromide and heparin are antagonists of these two phospholipase A 2 myotoxins, and that antagonism by the first two compounds may be due to a more specific interaction with these proteins than that by the latter.

The effect of road-type and distance transported on behaviour, physiology and carcass quality of farmed red deer ( Cervus elaphus)

Nine groups of six hinds were transported a range of distances (80, 230 or 380 km) that were representative of current commercial practice. Behaviour during transport was recorded continuously using a camera mounted centrally in the ceiling of the pen. Blood samples were collected pre-transport and post-slaughter, the carcasses were assessed for bruising and ultimate pH was measured. Adjustments to balance (rapid foot adjustments), and the number of impacts and movements by animals were greatest at the start of the journey and on the steep, winding roads. Overall bruising levels were low. Bruising on the hindleg and vertebrae increased with increasing distance transported. Biting accounted for 95% of all agonistic behaviour observed during transport. Heavier animals tended to initiate most of the agonistic behaviour and this was typically directed at the smaller animals. On two-thirds of the journeys one or more animals lay down. Deer tended to lie down after 60 min of the journey. Pre-slaughter handling (including transport) resulted in an increase in creatine kinase (CK), aspartate aminotransferase (AST), glucose, calcium, cortisol, total lactate dehydrogenase (LDH), LDH3, LDH4, LDH5 and a decrease in magnesium. Distance caused a further proportionate increase in plasma CK, total LDH, LDH5 and LDH4. This study shows that increasing distance transported has no additional effect on behaviour, carcass quality (bruising) or ultimate pH of red deer.

Creatine kinase release from regenerated muscles after eccentric contractions in rats.

The purpose of this study was to test the hypothesis that an increase in plasma creatine kinase (CK) activity after eccentric contractions (ECC) would be attenuated in regenerated muscle fibres. Adult male Wistar rats (aged 12-14 weeks) were randomly assigned to a treatment group (n = 14) or a control group (n = 10). In the treatment group, 1.2% barium chloride solution (BaCl2) was injected into the tibialis anterior (TA) and extensor digitorum longus (EDL) muscles to induce degeneration and subsequent regeneration. The same amount of isotonic saline solution was injected into TA and EDL for the control group. Histological observation showed that approximately 50% of the fibres in the transverse sections of both muscles underwent necrosis 2 days after BaCl2 injection. The CK activity increased about tenfold at 2-4 h after BaCl2 injection. At 4 weeks after BaCl2 injection, when the regeneration process was almost complete, the TA and EDL of anaesthetized rats from both groups were subjected to ECC in which maximal dorsiflexion was caused by nerve electrical stimulation and the flexed foot was forcibly extended by a lever arm connected to a motor. This action was performed in 2 sets of 30 repetitions. Maximal isometric torque of the dorsiflexors decreased to about 15% (P < 0.01) of the pre-ECC value immediately after the exercise. Blood samples were collected before and 2, 4, 12, 24, 48 h after ECC. The CK activity increased significantly (P < 0.01) and peaked at 2-4 h after ECC, and there was no significant difference in the amount of CK increase between the treatment [1007 (SEM 120) IU.l-1] and the control [1064 (SEM 120) IU.l-1] group. Contrary to the hypothesis, CK release after ECC was not attenuated in muscle regenerated from BaCl2-induced myonecrosis.

Carnitine musculaire chez les souris hyperammoniémiques: effet du traitement au benzoate de sodium

The object of this study was to measure carnitine levels in skeletal muscles of experimental mice with acute, subacute, and chronic hyperammonemia, with or without sodium benzoate treatment. Normal Swiss-ICR mice in which acute hyperammonemia was created through intraperitoneal injection of ammonium acetate showed a significant decrease in free carnitine in the skeletal muscles. The same phenomenon was observed in spf mice with chronic congenital hyperammonemia caused by an X-linked deficiency of liver ornithine transcarbamylase. In spf mice with subacute hyperammonemia created through treatment with an arginine-deficient diet, free carnitine of muscles increased compared with basal levels seen in chronic hyperammonemia. The changes in carnitine metabolism during chronic and subacute hyperammonemia were accompanied by a significant increase of creatine kinase levels in the plasma, which are an index of damage to the sarcolemma. A decrease in free and esterified levels of carnitine in the muscles was observed among normal mice treated with sodium benzoate. A decrease in esterified carnitine was also noticed among spf mice given an acute treatment with sodium benzoate as well as among normal and spf mice given a prolonged treatment with sodium benzoate. Plasma creatine kinase levels were high in normal mice, after both acute and prolonged treatments. However, the levels in spf mice treated with sodium benzoate were not significantly different from those in untreated spf controls in which a significant increase in plasma creatine kinase was already caused by chronic hyperammonemia.(ABSTRACT TRUNCATED AT 250 WORDS)