Creatine Kinase Activity Levels Research Articles

Wheat Germ Protein Powder: A Study on the Muscle Soreness Relief of Volleyball Players After Training

This paper briefly introduces wheat germ protein powder. The alleviating effect of wheat germ protein powder on muscle soreness was studied on 30 male athletes from the varsity volleyball team at the Faculty of Physical Education, Kunming University of Science and Technology. During the study, the athletes were divided into three groups: Group 1 received a kind of starch placebo, Group 2 received a low dose of wheat germ protein powder, and Group 3 received a high dose of wheat germ protein powder. Subjective pain, knee isokinetic muscle strength, and creatine kinase activity levels were measured at different time points before and after exercise. It was found that athletes who consumed wheat germ protein powder experienced faster alleviation of muscle soreness compared to those who took the starch placebo, and athletes who consumed a high dose of wheat germ protein powder demonstrated faster relief of muscle soreness compared to those who consumed a low dose.

Interleukin-4, Interleukin-1beta, and Creatine Kinase Changes to the DeLorme and Oxford Resistance Training Techniques

Background: Exercise intensity sequence of resistance training (RT) has a key role in the physiological response and adaptations. Objectives: The aim of the present study was to compare the effect of DeLorme and Oxford resistance training techniques on the concentration of interleukin-4 (IL-4), interleukin-1 beta (IL-1beta) and creatine kinase (CK) enzyme in overweight men. Methods: Thirty overweight young men (25 ≤ BMI < 30) voluntarily participated in the present study and were randomly assigned to the DeLorme (Del; n = 10), Oxford (OXF; n = 10) resistance training techniques and control (Con; n = 10). Del performed 4-5 sets at intensity of 50% of one-maximum repetition (1RM) for warm up, the second set with 85% of 1RM, the third set at 90% of 1 RM, and the fourth set at 95 of 1RM, and finally the fifth set at 100 1RM of exercise, while the OXF performed mentioned protocol exactly reverse order for eight weeks. RT was done three day/week in nonconsecutive for eight week. Blood sampling was gathered before RT, and repeated 72 hour after the last session of RT, and the levels of CK activity as well as the concentration of IL-4 and IL-1beta concentration were measured in the plasma. Results: The results showed that there was no significant difference between the Del and OXF in biochemical variables (P > 0.05). Also, in the IL-4, IL-1beta and CK, there were no improvement was found in the Del and OXF compared to the control (P > 0.05). Conclusions: Finally, it can be said that none of the Delorme and Oxford resistance training technique are preferred in improving systemic inflammatory factors, and the sequence of resistance training intensity is more or less and vice versa has no effect on improving systemic inflammatory factors.

Clinico-genetic spectrum of limb-girdle muscular weakness in Austria: A multicentre cohort study.

Background and purposeHereditary myopathies with limb‐girdle muscular weakness (LGW) are a genetically heterogeneous group of disorders, in which molecular diagnosis remains challenging. Our aim was to present a detailed clinical and genetic characterization of a large cohort of patients with LGW.MethodsThis nationwide cohort study included patients with LGW suspected to be associated with hereditary myopathies. Parameters associated with specific genetic aetiologies were evaluated, and we further assessed how they predicted the detection of causative variants by conducting genetic analyses.ResultsMolecular diagnoses were identified in 62.0% (75/121) of the cohort, with a higher proportion of patients diagnosed by next‐generation sequencing (NGS) than by single‐gene testing (77.3% vs. 22.7% of solved cases). The median (interquartile range) time from onset to genetic diagnosis was 8.9 (3.7–19.9) and 17.8 (7.9–27.8) years for single‐gene testing and NGS, respectively. The most common diagnoses were myopathies associated with variants in CAPN3 (n = 9), FKRP (n = 9), ANO5 (n = 8), DYSF (n = 8) and SGCA (n = 5), which together accounted for 32.2% of the cohort. Younger age at disease onset (p = 0.043), >10× elevated creatine kinase activity levels (p = 0.024) and myopathic electromyography findings (p = 0.007) were significantly associated with the detection of causative variants.ConclusionsOur findings suggest that an earlier use of NGS in patients with LGW is needed to avoid long diagnostic delays. We further present parameters predictive of a molecular diagnosis that may help to select patients for genetic analyses, especially in centres with limited access to sequencing.

Effects of Selenium Supplementation in Obese Selenocysteine Lyase Knockout Mouse (P24-022-19)

Abstract Objectives We previously demonstrated that disruption of selenocysteine lyase (Scly) in mice leads to the development of obesity and metabolic syndrome under selenium deficiency, with effects on glucose homeostasis in the liver. It is unknown whether the physiology of skeletal muscle, a key tissue in glucose disposal, is also affected by the disruption of Scly. Here, we investigated the effects of a high-fat diet supplemented with selenium in the muscle physiology of Scly knockout (KO) mice Methods Age-matched homozygous male and female Scly KO and wild type (WT) from C57BL/6 J background were group-caged and fed for three months to a diet containing 45% kcal fat and 0.25 ppm (adequate) or 1 ppm (high) of selenium as sodium selenite. Serum, liver, soleus, and brown adipose tissue (BAT) were collected and assessed for total glutathione peroxidase (GPX) activity and creatine kinase (CK). Total RNA was extracted from soleus and liver, reverse-transcribed, and used in qPCR. Results Following an adequate selenium intake, total GPX activity in serum, mRNA of GPX1 and selenoprotein P in the liver, and mRNA of selenoprotein N in soleus were unchanged of Scly KO compared to WT mice, both in males and females. We observed five-fold increase of CK activity in serum and a one-fold decrease in soleus of Scly KO male mice when compared with WT. Increased CK levels in serum have been related with muscle impairment. Interestingly, when male Scly KO mice were fed a high selenium diet, we observed the opposite effect, with serum CK activity significantly decreased, while in soleus CK activity increased in Scly KO mice. CK activity levels on liver or BAT were unchanged. CK activity in serum was unchanged in female mice, corroborating to the previously described sexual dimorphism for these animals. These results suggest an improvement in Scly KO muscle health after selenium supplementation. Conclusions Adequate selenium levels maintain selenium homeostasis and ensure the maintenance of selenoprotein levels, but high selenium intake may be necessary to preserve muscle health. Funding Sources FAPESP/Brazil, NIDDK-NIH/USA, NIMHD-NIH/USA.

Changes in the metabolic composition of storage solution with prolonged cold ischemia of the uterus.

The development of uterine transplantation (UTx) from deceased donors requires knowledge of the tolerance of the uterus to prolonged cold ischemia (CI). This can be evaluated through the use of biological parameters to assess degradation of the organ between its procurement and transplantation. The objective of this study was to analyze changes in the metabolic composition of the storage solution in cases of prolonged CI in uteri from ewes. Eighteen uterine auto-transplantations were performed in ewes. CI time was 1h (T1) or 24h (T24). Samples of Celsior® were taken when the explanted uterus was flushed (T0) and at the end of CI. A dual approach to metabolic analyses was followed: targeted biochemical analyses targeting several predefined metabolites and non-targeted metabolomics analyses based on nuclear magnetic resonance (NMR). Metabolic analyses were performed on 16 explanted uteri. Metabolomic profiles differed significantly between T1 and T24 (p = 0.003). Hypoxia-associated degradation of the organ was demonstrated by the significantly higher lactate levels at T24 than at T1 (p < 0.05), accompanied by cell lysis, and significantly higher levels of creatine kinase activity in T24 than in T1 uteri (p < 0.05). Oxidative stress increased over time, with a significantly higher oxidized glutathione/glutathione ratio for T24 than for T1 uteri (p < 0.05). The metabolic results indicate a significant degradation of the uterus during 24h of CI. Metabolic analysis of the storage solution could be used as a non-invasive tool for evaluating uterine degradation during CI before transplantation.

Impact of colibacillosis on production in laying hens associated with interference of the phosphotransfer network and oxidative stress

The objective of this study was to evaluate the productive impact of colibacillosis on laying hens and to investigate whether energetic metabolism and oxidative stress were involved in the pathogenesis of the disease. An experimental shed containing 270 laying hens of the Hy-Line lineage (32 weeks old) presented approximately 40% daily laying, and many birds presented with diarrhea and apathy followed by death. Necropsy revealed macroscopic lesions compatible with colibacillosis and infectious agent Escherichia coli was isolated from fecal samples of all birds in the infected group, as well as from tissue (ovary, liver and peritoneum). Sixteen chickens were selected for this study, divided into two groups: Control (animals without clinical alterations) and infected (with diarrhea and apathetic). E. coli isolates were subjected to the antimicrobial susceptibility testing according to the methodology approved by CLSI, 2018. This testing showed sensitivity to gentamicin, amoxicillin, norfloxacin and colistin. It was then determined that laying hens would be treated with norfloxacin (15 mg/kg) diluted in water offered at will to the birds for three days. Blood collections were performed via brachial vein after the diagnosis of E. coli (before starting treatment) and seven days after treatment. Three debilitated chickens died on the second day after initiating therapy. Before treatment, birds with clinical signs had higher levels of lipoperoxidation (LPO) and activities of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GPx) than in the control group (asymptomatic animals). After treatment, LPO levels remained higher in birds that had clinical disease (infected group), whereas the activity of SOD and GPx enzymes did not differ between groups. Activity levels of creatine kinase (CK) and pyruvate kinase (PK) were higher in the group of chickens with clinical disease before treatment. Post-treatment, no differences were observed between groups in terms of CK; however, PK activity remained high in these animals. In the hens that died, there were lesions characteristic of avian colibacillosis, with ovary involvement, explaining the low laying activity of the birds at their peak of production. For 10 days after starting treatment, the percentage of laying increased to 90%. Therefore, we conclude that colibacillosis interferes with the phosphotransfer network by stimulating ATP production, in addition to causing oxidative stress of the birds during laying, that negatively affects health and productive efficiency.

Metaphylactic effect of calcium on milk composition and animal health in post-partum dairy cows.

The aim of this study was to evaluate the effects of subcutaneous calcium administration in post-partum dairy cows with respect to carbohydrate, protein and lipids metabolism, as well as its effects on milk composition. Twenty post-partum dairy cows were randomly divided into two groups (n=10): a control and a treated group with a single dose (150 mL) of calcium. Blood collection was performed on post-partum days 1, 2, 3, 7 and 10. In addition, we measured serum levels of total calcium, total proteins, albumin, globulins, glucose, cholesterol, triglycerides, as well as creatine kinase (CK) activity. We determined milk composition on post-partum days 5, 10 and 20. Serum total calcium levels was higher on post-partum days 3 and 7 in the treated group. Serum urea (day 3) and triglycerides (days 7 and 10) levels were higher in the treated group, as were CK activity levels at post-partum days 2 and 3. Serum glucose and cholesterol levels were lower on post-partum day 2 in treated animals. Fat (day 20) and lactose (day 10) content in milk samples were higher than in the treated animals. We concluded that treatment with calcium in cows during the post-partum period changes biochemical variables related to metabolism.

Creatine kinase and blood pressure in women with a history of early-onset preeclampsia.

High plasma creatine kinase (CK) activity is associated with hypertension in the general and pregnant population. We hypothesize that women with a history of early-onset preeclampsia are prone to hypertension due to a high CK activity level. Nine to 16 years after pregnancy, serum CK activity and blood pressure were measured in 117 women with a history of early-onset preeclampsia and 50 women with a history of an uncomplicated pregnancy. CK activity levels of the two groups were compared using the Mann-Whitney U test. The association between CK activity and blood pressure was evaluated by means of multivariable regression analysis. There was no significant difference in median (interquartile range) CK activity between women with a history of early-onset preeclampsia and an uncomplicated pregnancy (59.00 [47.00-85.00] vs. 58.00 [46.50-75.25], respectively, p = 0.774). The association between CK and systolic blood pressure was significant in women with a pregnancy history of early-onset preeclampsia (regression coefficient [95% confidence interval]: 0.123 mmHg [0.020-0.226], p = 0.019), and a trend was found for diastolic blood pressure (p = 0.069). CK and blood pressure were not significantly associated in women with a history of an uncomplicated pregnancy. Median CK did not significantly differ between the two groups. Serum CK activity was significantly associated with systolic blood pressure in women with a history of early-onset preeclampsia. These data suggest that CK is not a predominant factor in the increased risk of hypertension in women with a history of early-onset preeclampsia.

449. IGF-1 Treatment Enhances the Myogenic Potential of Human Skeletal Muscle-Derived Stem Cells

Human muscle-derived stem cells (hMDSCs) have been shown to promote the regeneration of a variety of tissues, including damaged heart, peripheral nerve, bone, articular cartilage and skeletal muscle1xSee all References, 2xSee all References, 3xSee all References; however, without appropriate stimulation their differentiation potential remains limited.4xSee all References In this study we examined whether insulin-like growth factor 1 (IGF-1) treatment could also enhance the myogenic potential of hMDSC, since it has been shown that IGF-1 treatment increased the myogenic potential of bone marrow-derived stem cells (BMSCs).5xSee all References Methods: HMDSCs were isolated from human adult muscle biopsies via a modified preplate technique, as previously described.6xSee all References Young female hMDSCs were plated in proliferation medium at a density of 1.58 × 104 cells/cm2. After 24h in proliferation medium, the cells were cultured for an additional 7 days in myogenic medium containing various levels of IGF-1: 0ng/mL, 50 ng/mL, 100 ng/mL, or 200 ng/mL. To evaluate the extent of myogenesis, cells were fixed in MeOH and stained for fast myosin heavy chain (fMHC). Activity levels of creatine kinase, which is highly expressed in tissues like skeletal muscle that rapidly consume ATP, were measured according to the company's protocol. Additionally, RNA was extracted from cells, and cDNA was synthesized. Semi-quantitative PCR and qRT-PCR analyses were performed for myogenin, a late myogenic differentiation marker. Results: (1) fMHC staining indicated that IGF-1 treatment increased myotube formation (Fig. 1AFig. 1A). However, the mortality rates of the cells in all IGF-1 treatment groups were increased compared to the non-treated group. (2) hMDSCs treated with 50 ng/ml IGF-1 had significantly higher CK activity compared to all other groups when normalized to total protein. Furthermore, cells treated with 200 ng/ml IGF-1 also had significantly more CK activity than the untreated cells. This suggests that IGF-1 may enhance CK activity at low levels. At higher IGF-1 concentrations, CK activity may be reduced due to increased cell death (Fig. 1BFig. 1B). (3) Semi-quantitative analysis showed that IGF-1 treatment, at all concentrations, increased myogenin expression. The 100ng/mL concentration appeared to have the greatest effect. These results were corroborated by qRT-PCR analysis, which indicated that, compared to the non treated group, the 50ng/mL, 100ng/mL, and 200ng/mL groups had a 16.1 fold, 30.1 fold, and 14.3 fold increase in myogenin expression, respectively. Conclusion: These results indicate that IGF-1 enhances the myogenic potential of hMDSCs. However, we observed more cell death in IGF-1 treatment groups, which may be a result of overgrown cells during differentiation. In the future, we will determine whether IGF-1 treated hMDSCs display a higher regenerative potential in skeletal muscle, after injury and disease, than non-treated hMDSCs.View Large Image | Download PowerPoint SlideView Large Image | Download PowerPoint Slide

Association of heat shock protein 70 gene polymorphisms with acute thermal tolerance, growth, and egg production traits of native chickens in Taiwan

Abstract. Heat stress is among the most challenging environmental conditions affecting commercial poultry. It severely affects growth and egg production, particularly in tropical and subtropical regions. This study aimed to examine physiological responses – including triiodothyronine (T3) levels, enzymatic activity of creatine kinase (CK) and lactate dehydrogenase (LDH), respiratory rates, and cloacal temperature – to acute heat stress associated with different genotypes of the HSP70 gene and to evaluate the association of these polymorphisms with growth and egg production. Genotyping was performed by single-strand conformation polymorphism analysis. The polymorphisms identified were A258A, A258G, and G258G. Twenty 12-week old birds were randomly selected from each genotype and exposed to 40 °C ambient temperature for 1 h. Blood samples were collected at 0 and 1 h following heat stress. Respiratory rate and cloacal temperature were measured following 0, 30, and 60 min of exposure. After 1 h, the A258A genotype exhibited lower levels of CK activity and plasma T3. Neither respiratory rate nor cloacal temperature displayed a significant association with the genotypes. Body weight gain differed among the genotypes for males (F = 3.268, P = 0.041) and females (F = 14.029, P &lt; 0.001), and the A258A genotype exhibited the greatest weight gain at 0–16 weeks of age for both genders. There were no significant differences among genotypes regarding egg weight at first egg or the number of eggs laid until 40 weeks of age. The A258A genotype displayed higher heat tolerance with no negative effects on growth performance and egg production.

The relationship of creatine kinase variability with body composition and muscle damage markers following eccentric muscle contractions.

[Purpose]The purpose of the study was to investigate the relationship between CK variability and body composition and muscle damage markers following eccentric exercise.[Methods]Total 119 healthy male subjects were recruited to perform 50 eccentric contractions consisted of 2 sets of 25 contractions. Then, blood creatine kinase (CK) activity was analyzed to divide into three groups based on their CK activity levels. Maximum isometric strength (MIS), muscle soreness (SOR) and body composition data were obtained before and after exercise.[Results]The results showed that high CK responders had a significant decrease in MIS (p<0.001) and greater SOR (p<0.01) following eccentric exercise compared to low CK responders. Percent body fat was also higher in high responders compared to low responders (p=0.014). Peak CK activity was significantly correlated with MIS and SOR but no correlation with % body fat, muscle mass, and body mass index.[Conclusion]CK variability following eccentric exercise is closely related to MIS and SOR and % body fat may be a potent factor for CK variability.

Dihydromyricetin Improves Physical Performance under Simulated High Altitude

Dihydromyricetin (DHM) is the major bioactive constituent of rattan tea. Our aim was to investigate the possible mechanism and the effect of DHM in counteracting hypobaric hypoxia (HH)-induced exercise intolerance. Male Sprague-Dawley rats were pretreated with three doses of DHM (50, 75, and 100 mg · kg(-1)) for 7 d and subjected to simulated high-altitude conditions (5000 m with 10.9% oxygen). Physical performance was assessed with the run-to-fatigue model. Mitochondrial morphology in the gastrocnemius muscle was observed by transmission electron microscopy. Protein expression was detected by western blotting. The activity of mitochondrial electron transport chain was analyzed by enzyme-linked immunosorbent assay. DHM administration prolonged the run-to-fatigue time in a dose-dependent manner compared with the control (22.9 ± 2.2, 46.1 ± 4.4, 61.3 ± 3.1 vs 18.4 ± 1.7 min, which represented 50, 75, 100 mg · kg(-1), and the control groups, respectively). DHM also reduced serum blood urea nitrogen, lactate dehydrogenase, and creatine kinase activity levels. HH-induced mitochondrial injuries, including morphological changes, reduction in mitochondrial density and mitochondrial DNA content, and decrease in respiratory chain complex (I, II, IV, and V) activities were effectively attenuated by DHM. Protein expression of mitochondrial biogenesis markers, including peroxisome proliferator-activated receptor-γ coactivator 1α, sirtuin 1, nuclear respiratory factor 1, mitochondrial transcription factor A, AMP-activated protein kinase, and AMP-activated protein kinase phosphorylation, was significantly downregulated in HH, whereas DHM pretreatment significantly restored expression levels. DHM also modulated mitochondrial dynamics of fusion and fission by increasing mitofusins 1 and 2, while decreasing fission-related, dynamin-related protein 1 and mitochondrial fission 1. DHM improves physical performance under simulated high-altitude conditions via protecting mitochondrial biogenesis and modulating mitochondrial dynamics in skeletal muscle cells.

Remote ischemic postconditioning protects the heart by upregulating ALDH2 expression levels through the PI3K/Akt signaling pathway.

Remote ischemic postconditioning (RIPostC) has been demonstrated to protect the myocardium against ischemia/reperfusion (I/R) injury; however, the mediator and underlying mechanisms remain to be elucidated. It has been confirmed that aldehyde dehydrogenase2 (ALDH2) is involved in the remote ischemic preconditioning pathway, but whether it is involved in RIPostC remains unknown. The aim of the present study was to determine whether increased ALDH2 expression levels were involved in the cardioprotective effect evoked by RIPostC via the phosphatidylinositol‑3‑kinase (PI3K)/Akt signaling pathway. Male Sprague Dawley rats (n=48) were randomly allocated into the following four groups: Sham group, I/R group, RIPostC group, and RIPostC plus wortmannin group (RIPostC+Wort). With the exception of the Sham group, the anesthetized rats underwent 45min of coronary artery occlusion followed by 180min of reperfusion to mimic an I/R injury model. Hemodynamic parameters, including the mean arterial pressure and heart rate, were recorded, the infarct size was determined and the plasma lactate dehydrogenase (LDH) content and creatine kinase (CK) activity levels were measured. The expression levels of Bcl‑2 and Bax at the mRNA level and ALDH2, Akt, phospho‑Akt (p‑Akt), caspase‑3 and cleaved caspase‑3 at the protein level in the left anterior myocardium were assessed. In the RIPostC group, the infarct size was reduced versus that of the I/R group. The plasma LDH content and CK activity levels were also reduced. The expression levels of ALDH2 protein were elevated, accompanied with increases in the levels of Bcl‑2/Bax and p‑Akt/Akt and a reduction in the levels of cleaved caspase‑3. When the PI3K inhibitor wortmannin was administered at reperfusion, the p‑Akt/Akt ratio was markedly reduced and associated with a reduction in the ALDH2 and Bcl‑2/Bax levels, and the cleaved caspase‑3 expression levels were elevated. In conclusion, ALDH2 may be an important mediator in the cardioprotection of RIPostC through the PI3K/Akt‑dependent signaling pathway.

Effects of methionine supplementation on the redox state of acute heat stress–exposed quails1

The aims of the present study were to evaluate the possible effects of heat stress (HS) on H2O2 production and to evaluate whether methionine supplementation (MS) could mitigate the deleterious effects on cell metabolism and the redox state induced by oxidative stress. Meat quails (Coturnix coturnix coturnix) were fed a diet that either met the nutritional demands for methionine or did not meet this demand (methionine deficient [MD] diet) for 7 d. The animals were either kept at a thermal comfort temperature (25°C) or exposed to HS (38°C for 24 h, starting on the sixth day). Heat stress induced decreased food intake (P = 0.0140), decreased daily weight gain (P < 0.0001), and increased water intake (P = 0.0211). A higher rate of H2O2 production was observed in HS animals (0.0802 vs. 0.0692 nmol of reactive oxygen species [ROS] produced per minute per milligram of protein; P = 0.0042) and in animals fed with the MD diet (0.0808 vs. 0.0686 nmol of ROS produced per minute per milligram of protein; P = 0.0020). We observed effects of the interaction between diet and the environment on the activities of glutathione peroxidase (GP-x) and catalase (P = 0.0392 and P < 0.0001, respectively). Heat stress induced higher levels of GP-x activity in animals on the MS diet and higher catalase activity in animals on the MD diet. Glutathione (GSH) levels were higher in animals on the MS diet (P = 0.0273) and in animals that were kept in thermal comfort (P = 0.0018). The thiobarbituric acid reactive substances level was higher in HS animals fed with the MD diet (P = 0.0386). Significant effects of the interaction between supplementation and environment were observed on uric acid concentration levels, which were higher in HS animals fed the MS diet (P = 0.008), and on creatine kinase activity levels, which were lower in HS animals fed the MD diet (1,620.33 units/L; P = 0.0442). Our results suggest that under HS conditions, in which H2O2 production is increased, MS was able to mitigate ROS-induced damage, possibly by increasing the activities of antioxidant elements such as GSH, GPx activity, and uric acid concentration, which were present in higher levels in animals that were subjected to HS and fed the MS diet.

Laboratory Test Abnormalities are Common in Polymyositis and Dermatomyositis and Differ Among Clinical and Demographic Groups

Objective:Given the difficulties regarding the interpretation of common laboratory test results in polymyositis (PM) and dermatomyositis (DM) in clinical practice, we assessed their range of abnormalities, differences among phenotypes and interrelationships in a large referral population.Methods:We retrospectively assessed 20 commonly measured blood laboratory tests in 620 well-defined PM/DM patients at different stages of illness and treatment to determine the frequency, range of abnormalities and correlations among clinical, gender, racial and age phenotypes.Results:Myositis patients at various stages of their disease showed frequent elevations of the serum activities of creatine kinase (51%), alanine aminotransferase (43%), aspartate aminotransferase (51%), lactate dehydrogenase (60%), aldolase (65%) and myoglobin levels (48%) as expected. Other frequent abnormalities, however, included elevated high white blood cell counts (36%), low lymphocyte counts (37%), low hematocrit levels (29%), low albumin levels (22%), high creatine kinase MB isoenzyme fractions (52%), high erythrocyte sedimentation rates (33%) and high IgM and IgG levels (16% and 18%, respectively). Many of these tests significantly differed among the clinical, gender, racial and age groups. Significant correlations were also found among a number of these laboratory tests, particularly in the serum activity levels of creatine kinase, the transaminases, lactate dehydrogenase and aldolase.Conclusion:Laboratory test abnormalities are common in PM/DM. Knowledge of the range of these expected abnormalities in different myositis phenotypes, gender and age groups and their correlations should assist clinicians in better interpretation of these test results, allow for a clearer understanding what level of abnormality warrants further evaluation for liver or other diseases, and may avoid unnecessary laboratory or other testing.

Selective estrogen receptor‐β activation stimulates skeletal muscle growth and regeneration

There is increasing evidence suggesting that estrogens augment skeletal muscle regeneration processes after injury. To study the contribution of estrogen receptors α and β (ERα and ERβ) during muscle regeneration, skeletal muscles of ovariectomized (OVX) rats, as well as ERα- and ERβ-knockout (αErko and βErko) mice, were injured with a myotoxin (notexin). OVX rats were simultaneously treated with the ER-selective ligands genistein, ERα agonist 16α-LE2 (alpha), ERβ agonist 8β-VE2 (beta), or 17β-estradiol (E(2)). OVX rats showed significantly elevated serum creatine kinase (CK) activity after muscle injury compared to intact sham-treated animals. Treatment with ER ligands significantly reduced CK activity. TNF-α, IL-10, and MCP-1 expression served to characterize immune responses. Treatment with all ER ligands, but particularly E(2) and beta, reduced TNF-α, but elevated MCP-1 and IL-10 expression. PCNA and MyoD expression served to define satellite cell activation and proliferation and were found to be up-regulated by beta and E(2). To further study muscle regeneration responses, expression of the embryonic myosin heavy chain (MHC) was analyzed. Beta and E(2) but not alpha increased embryonic MHC expression compared to OVX. The absence of ERβ in βErko mice negatively affected CK activity levels and expression of satellite cell and muscle regeneration markers (MHC embryonic, MyoD, Pax7) compared with αErko and wild-type mice. In a classic Hershberger assay using male rats, beta stimulated muscle growth, accompanied by a strong induction of IGF-1 expression. Our data provide evidence that ERβ signaling is involved in the regulation of skeletal muscle growth and regeneration by stimulating anabolic pathways, activating satellite cells and modulating immune responses.

Therapeutic Ultrasound Affects IGF-1 Splice Variant Expression in Human Skeletal Muscle

Background: Animal models of skeletal muscle damage and repair demonstrate that therapeutic ultrasound (TUS) enhances muscle force recovery after damage, increases satellite cell proliferation, and decreases insulin-like growth factor (IGF)-1 splice variant (mechano growth factor) gene expression. However, these effects have not been verified in humans. Purpose: This study was undertaken to examine the 3 known splice variants of the IGF-1 gene in human skeletal muscle after damage and TUS treatment. Study Design: Controlled laboratory study. Methods: Sixteen healthy men (18-29 years of age), physically active, were randomized to either a control (CON) or experimental group (EXP). The EXP group underwent 200 lengthening contractions (muscle damage) of the quadriceps of both legs, 48 hours before TUS. Both groups received TUS, delivered for 10 minutes on a standardized area of the vastus lateralis of only 1 leg (1.0 MHz, 1.5 W/cm2). Bilateral muscle biopsy samples were taken from all participants, 6 hours after TUS. Total RNA was extracted, and quantitative real-time polymerase chain reaction conducted for each IGF-1 splice variant. Results: Muscle damage was confirmed by a decrease in the isometric peak torque and increase in creatine kinase activity levels 48 hours after damage (P < .01). After muscle damage, gene expression of total IGF-1 and 2 IGF-1 splice variants increased. Therapeutic ultrasound induced significant increase in IGF-1Eb gene expression in undamaged muscle (1.4 ± 0.2-fold, P < 0.01). In damaged skeletal muscle, no significant change in gene expression attributable to TUS was determined. Conclusion: Insulin-like growth factor–1 splice variants are differentially regulated in human skeletal muscle in response to exercise-induced muscle damage and TUS treatment. A single treatment of TUS in damaged muscle induces no change in the gene expression of the 3 IGF-1 splice variants in humans. In contrast, in undamaged skeletal muscle, TUS significantly increased IGF-1Eb splice variant gene expression. Clinical Relevance: These findings suggest that TUS may have additional therapeutic uses beyond its current common practice but may not be effective for muscle injury treatment in a young, healthy population.

Short Recovery Augments Magnitude of Muscle Damage in High Responders

To examine serum creatine kinase (CK) activity after resistance exercise bouts with different rest intervals between sets and exercises in high responding (HR) and normal responding (NR) subjects. During each resistance exercise bout, three sets with 10-repetition maximum (10RM) loads were completed for the chest press, cable pulldown, biceps curl, triceps extension, leg extension, and prone leg curl. Each bout differed in the length of the rest interval between sets and exercises, specifically either 1 or 3 min. After blood analysis, subjects were separated into NR or HR on the basis of the peak serum CK activity being in the 90th percentile. The volume completed (load x sets x repetitions) was significantly greater for the 3-min bout versus the 1-min bout, with no significant differences between the HR and the NR groups. For the NR group, serum CK was significantly elevated from 24 to 72 h after each bout, with no significant differences between bouts. Conversely, for the HR group, the 1-min bout resulted in serum CK activity levels that were approximately 70% greater than the 3-min bout at the 48- and 72-h time points. The key finding from the current study was that the HR group experienced significantly greater CK responses when using shorter rest intervals between sets. Conversely, for the NR group, CK responses were not significantly different between bouts. These findings may have implications for resistance exercise prescription in that some individuals might be less tolerant of shorter rest intervals between sets with greater skeletal muscle microtrauma.

An evaluation of changes over time in serum creatine kinase activity and C-reactive protein concentration in dogs undergoing hemilaminectomy or ovariohysterectomy

The extent of trauma in a patient can be difficult for a clinician to quantify. A prospective study was performed on 2 groups of dogs undergoing either ovariohysterectomy or hemilaminectomy. The serum activity of creatine kinase and serum concentration of C-reactive protein were evaluated preoperatively and then at 4, 6, 8, 12, 24 and 48 hours postoperatively in both groups. The results were compared statistically both within and between the 2 groups. A wide range of results was found at each time point for both analytes although there were no significant differences for either analyte between the 2 surgical groups preoperatively. Thereafter there were significant differences in creatine kinase activity levels between the 2 groups. C-reactive protein concentration results were very similar in the 2 groups with no statistical difference at any time point. The results of this study suggest that the evaluation of CK and CRP at any one time point in a traumatised animal is of limited value. However, the evaluation of the trend of these 2 analytes, even over a relatively short time period, may allow for useful prognostication in clinical cases.

Effects of Acetic Acid Bacteria Supplementation on Muscle Damage After Moderate-Intensity Exercise

Objective: Acetic acid bacteria were traditionally used to produce fermented food. Furthermore, acetic acid bacteria contain unique membrane lipids that would be expected to attenuate inflammation. This study examined the effects of oral intake of acetic acid bacteria isolated from fermented milk on muscle damage after moderate-intensity exercise.Methods: In a double-blind placebo-controlled crossover trial, 40 untrained subjects (16 men and 24 women; age, 46.4 ± 4.3 yr; height, 162.8 ± 10.8 cm; weight, 60.2 ± 9.4 kg; body mass index, 22.6 ± 2.9 kg/m2) took 111 mg of dried acetic acid bacteria per day (supplemented group) or 111 mg of cornstarch per day (placebo group) for 1 week and walked for 60 min on the last day of administration. Results: Leukocyte, lymphocyte and neutrophil counts, IL-6 and creatine kinase (CK) activity, myoglobin (Mb) concentration and perceived pain in parts of the body were measured pre and post exercise. All values, except for IL-6, were significantly increased post-exercise compared with pre-exercise in both groups. However, neutrophil counts and ankle pain were significantly lower in the supplemented group. In addition, the increase of CK activity in the supplemented group was significantly attenuated at 24 h after exercise (supplemented group, 114 ± 54 U/l; placebo group, 126 ± 68 U/l). The supplemented group also demonstrated a trend toward a lower level of CK activity after exercise (p = 0.06). Other values did not differ between groups. Conclusion: These results suggested that acetic acid bacteria supplementation was useful to attenuate muscle damage after moderate-intensity exercise.