Total Creatine Kinase Activity Research Articles

Creatine kinase and its isoenzymes in the serum and cerebrospinal fluid of healthy canines.

Creatine kinase (CK) exists as three isoenzymes (CK-MM, CK-MB, and CK-BB) that are predominantly expressed in specific tissues and can be detected in both the serum and cerebrospinal fluid (CSF). CSF CK has been relatively unstudied in veterinary medicine, although studies in human medicine have demonstrated that changes in total CSF CK activity can indicate neurologic abnormalities. The purpose of this study was to establish reference intervals for CK and its three major isoenzymes in the serum and CSF of clinically healthy dogs. By establishing a definitive reference interval for this enzyme in healthy canines, the diagnostic use and possible significance of CK in clinical disease can be studied. Serum and/or CSF were collected from healthy dogs. Total CK activity was measured spectrophotometrically, and isoenzyme distributions were determined using the QuickGel CK Vis Isoenzyme Kit and a densitometric scanner. Total CK and CK isoenzyme activities were determined within 8 h of collection. The median serum total CK in healthy canines was 159.0 U/L (range: 53.0-539.0 U/L), while the median CSF total CK was 3.7 U/L (range: 2.0-84.0 U/L). CK-BB and CK-MM were approximately equal in the serum, while CK-MM was the predominant isoenzyme in the CSF. Knowledge of the normal distribution and concentration of CK in canine serum and CSF will set the foundation for future studies of canine CK as a potentially clinically useful biomarker.

Evaluation of creatine kinase (CK)-MB to total CK ratio as a diagnostic biomarker for primary tumors and metastasis screening

ObjectiveCreatine kinase (CK) and its myocardial band isoenzyme (CK-MB) were considered important diagnostic indicators for identifying suspected acute myocardial infarction. However, the serum level of CK-MB is frequently exaggerated in some pathological states without cardiogenic damage, like cancer. Sometimes, the CK-MB level is even greater than the total CK. This study intended to investigate the association between malignancy and an abnormally high ratio of CK-MB to total CK (CK-MB/CK) and to assess the diagnostic relevance of this ratio as a biomarker for cancer. MethodsPatients hospitalized between September 2019 and September 2022 at Shandong Provincial Qianfoshan Hospital (Jinan, Shandong, China) with serum CK-MB activity greater than total CK activity (CK-MB/CK > 1.0) were recruited as research subjects. Then the demographic and clinical characteristics of these patients were systemically analyzed. The correlation between clinical characteristics (such as cancer types, tumor locations, and tumor metastasis) and laboratory test results (such as serum CK-MB activity, total CK activity, and the CK-MB/CK ratio) was also investigated. ResultsWe found that over 44% of the patients with CK-MB/CK > 1.0 were diagnosed with malignancies, and the CK-MB/CK ratio in malignancies patients was significantly higher than in non-malignancies patients. The increase of CK-MB/CK ratio was most obvious in patients with colorectal carcinoma and prostatic carcinoma. Additionally, extremely elevated CK-MB/CK ratios were observed in individuals with metastatic neoplasms, especially in those who suffered from numerous sites of metastasis. ConclusionsThe serum CK-MB/CK ratio can be utilized as a readily accessible supplement diagnostic biomarker in screening for primary and metastatic cancers.

Disruption of Bioenergetics in the Intestine of Wistar Rats Caused by Hydrogen Sulfide and Thiosulfate: A Potential Mechanism of Chronic Hemorrhagic Diarrhea in Ethylmalonic Encephalopathy.

Ethylmalonic encephalopathy (EE) is a severe inherited metabolic disorder that causes tissue accumulation of hydrogen sulfide (sulfide) and thiosulfate in patients. Although symptoms are predominantly neurological, chronic hemorrhagic diarrhea associated with intestinal mucosa abnormalities is also commonly observed. Considering that the pathophysiology of intestinal alterations in EE is virtually unknown and that sulfide and thiosulfate are highly reactive molecules, the effects of these metabolites were investigated on bioenergetic production and transfer in the intestine of rats. We observed that sulfide reduced NADH- and FADH2-linked mitochondrial respiration in the intestine, which was avoided by reduced glutathione (GSH) but not by melatonin. Thiosulfate did not change respiration. Moreover, both metabolites markedly reduced the activity of total, cytosolic and mitochondrial isoforms of creatine kinase (CK) in rat intestine. Noteworthy, the addition of GSH but not melatonin, apocynin, and Trolox (hydrosoluble vitamin E) prevented the change in the activities of total CK and its isoforms caused by sulfide and thiosulfate, suggesting a direct protein modification on CK structure by these metabolites. Sulfide further increased thiol content in the intestine, suggesting a modulation in the redox state of these groups. Finally, sulfide and thiosulfate decreased the viability of Caco-2 intestinal cells. Our data suggest that bioenergetic impairment caused by sulfide and thiosulfate is a mechanism involved in the gastrointestinal abnormalities found in EE.

Myocardial damage biomarkers and the first case of macrotroponin I detection in endurance athletes

Background. High levels of cardiac troponin in the blood indicates myocardial injury, including those caused by intense exercises. Recent studies have shown that an elevation in the troponin concentration in the patients can be caused by the macrotroponin circulation. There is no data in the scientific literature describing this problem in athletes.The aim. To identify the cases and possible causes of high blood levels of cardiac markers in athletes before and after endurance exercises.Materials and methods. The study was conducted on 11 male cross-country skiers aged 15–21 years. The study included two stages: the first was conducted at the end of the preparatory period (November, 2020–2021), the second – in the middle (March) of the 2020–2021 competitive period. At each stage, two blood samples were taken from a vein: the first – in the morning on an empty stomach after a day of rest, the second – 12–14 hours after a high-intensity exercise. In the blood serum, the activity of total creatine kinase (CK), weight concentration of the cardiac isoenzyme of creatine kinase (CK-MB), and concentration of high sensitive troponin I (Tn) were measured.Results. The activity of CK in athletes exceeded the upper limit threshold, and decreased from the preparatory (November) to the competitive (March) period. The concentration of CK-MB in response to exercise increased by 2 times and was not accompanied by the signs of myocardial injury. The most sensitive indicator, responsive to physical activity, was troponin I. However, the highest elevation of Tn in blood of one athlete, both before and after the exercise, was associated with the presence of macrotroponin without signs of myocardial injury.Conclusions. An increase of muscle tissue injury biomarkers in blood, including the heart muscle (CK, CK-MB, and Tn), by 2–4 times is a typical reaction for the body of a cross-country skier to an intense exercise. High levels of troponin in the blood, both before and after training or competition, may be associated with the presence of macrotroponin.

Distinct signatures on d-galactose-induced aging and preventive/protective potency of two low-dose vitamin D supplementation regimens on working memory, muscular damage, cardiac and cerebral oxidative stress, and SIRT1 and calstabin2 downregulation.

Chronic administration of d-galactose (d-gal) in rodents reproduces the overproduction of reactive oxygen species of physiological aging. The present research shows for the first time distinct signatures on d-gal-induced aging (500 mg/kg, 6 weeks) and the preventive and protective potential of two vitamin D (50 IU) supplementation regimens (pre-induction and simultaneous, respectively) in two vital organs (heart and brain). d-gal-induced notorious alterations in working memory, a strong increase in brain malondialdehyde (MDA) oxidative levels, and strong downregulation of sirtuin 1 (SIRT1) in the heart and hippocampus and of calstabin2 in the heart. Cardiac and brain superoxide dismutase (SOD) and glutathione peroxidase (GPx) enzymatic antioxidant capacities were damaged, brain calstabin2 was downregulated, and neuropathology was observed. Heart damage also included a moderate increase in MDA levels, serologic lactate dehydrogenase (LDH), total creatine kinase (CK) activities, and histopathological alterations. The used dose of vitamin D was enough to prevent cognitive impairment, avoid muscular damage, hamper cardiac and cerebral oxidative stress, and SIRT1 and calstabin2 downregulation. Most importantly, the potencies of the two preventive schedules depended on the tissue and level of study. The pre-induction schedule prevented d-gal-induced aging by 1 order of magnitude higher than simultaneous administration in all the variables studied except for SIRT1, whose strong downregulation induced by d-gal was equally prevented by both schedules. The benefits of vitamin D for oxidative stress were stronger in the brain than in the heart. Brain MDA levels were more sensitive to damage, while SOD and GPx antioxidant enzymatic activities were in the heart. In this order, the magnitude of SOD, MDA, and GPx oxidative stress markers was sensitive to prevention. In summary, the results unveiled distinct aging induction, preventive signatures, and sensitivity of markers depending on different levels of study and tissues, which are relevant from a mechanistic view and in the design of targeted interventions.

Normal values of creatine kinase and of MB-creatine kinase at birth in healthy babies

Today, few studies have been accomplished in order to determine serum creatine kinase (CK) activity in newborns by considering small groups of babies and without taking into account gestational age (GA) differences. Some authors have demonstrated that neonatal CK activity value at birth is higher than the normal range of CK activity considering for adults or older children. The objective of this study is to assess normal values of CK and MB-CK in neonatal blood, according to babies' GA. We retrieved the clinical files of 140 babies admitted into Siena Hospital NICU in a 2-years period, when CK was assessed routinely to all babies at birth. We selected files from 114 newborns and we divided the cohort into group A (non-stressed; N.=41) and group B (stressed; N.=73) on the basis of Apgar Score and signs of neurological lesions. We compared CK and MB-CK values in the two groups according to GA. Mean CK value of the 41 non-stressed babies' samples: 413 IU/L (232 SD). CK significantly increases with GA. No differences are present in total CK activity between stressed vs. non-stressed babies; but a significant difference appears in these two groups for MB-CK (mean values: 456 vs. 175 IU/L). This is the first study that compares CK and MB-CK values at birth according to the GA of the babies. CK values increase with GA, and stressed babies have higher MB-CK values than the non-stressed babies. These reference values are important for clinical practice.

Determination of the effect of iatrogenic blood contamination on lactate dehydrogenase and creatine kinase activity in canine cerebrospinal fluid.

Lactate dehydrogenase (LDH) and creatine kinase (CK) have differential tissue activity and isoenzyme profiles. LDH and CK exist as 5 and 3 isoenzymes, respectively, in both serum and cerebrospinal fluid (CSF). Studies have demonstrated that measuring LDH, CK, and their isoenzymes in CSF has diagnostic and prognostic values for dogs and people with neurologic disorders. Iatrogenic blood contamination can distort the results of CSF analysis. The purpose of this study was to determine allowable thresholds of blood contamination (RBC/μL) for accurate measurement of LDH, CK, and their isoenzymes in canine CSF. Venous blood and CSF were collected from healthy dogs. Total LDH and CK activity were measured spectrophotometrically. Isoenzyme profiles were determined using gel electrophoresis and densitometric scanning. All samples were analyzed within 6hours of collection. A nonlinear mixed effects regression model was used to estimate the allowable thresholds of blood contamination for accurate measurement of LDH, CK, and their isoenzymes in canine CSF. The threshold of iatrogenic blood contamination for total LDH and total CK in healthy dogs are 6696 RBC/μL (95% CI 3879-11 187) and 5961 RBC/μL (95% CI 2939-12 085), respectively. LDH-1 is the most sensitive isoenzyme to iatrogenic blood contamination, while LDH-4 is the least sensitive. These results are important for the interpretation of LDH, CK, and their isoenzymes in canine CSF. Additionally, our methodology is translatable for determining thresholds of acceptable iatrogenic blood contamination in CSF for other diagnostic and prognostic biomarkers of neurologic disease.

Biochemical blood profile in 20 female veiled chameleons (Chamaeleo calyptratus) Aged 7, 9 and 11 Months

Veiled chameleons ( Chamaeleo calyptratus ) are more frequently presented to veterinary clinics due to reproductive diseases that lead to high morbidity, especially in captive-bred females. The objective of this study was to evaluate blood biochemical profiles of healthy, young captive females veiled chameleons aged seven, nine and eleven months. Blood samples were taken from 20 female veiled chameleons at the age of 7, 9 and 11 months. The biochemical profile was analyzed using the VetScan VS2 analyzer with an Avian/Reptile Profile rotor. The ionized calcium (iCa) concentration was measured by i-STAT analyzer with a CHEM+8 cartridge. Mean concentration of glucose (15.8 ± 1.3 mmol/l) and uric acid (244.3 ± 143.2 µmol/l) at the age of seven months were significantly higher than mean concentrations of glucose (12.8 ± 16.5 mmol/l) and uric acid (134.9 ± 113.2 µmol/l) at nine months of age and mean concentration of glucose (13.2 ± 0.9 mmol/l) and uric acid (129.4 ± 109.2 µmol/l) at 11 months of age, respectively. Total calcium (4.2 ± 0.8 mmol/l) and ionized calcium (1.51 ± 0.16 mmol/l) were significantly higher at seven months of age compare to nin months. Mean activity of aspartate aminotransferase at nine months (6.2 ± 2.3 µkat/l) was significantly higher (P=0.004) than the mean activity of aspartate aminotransferase at seven months of age (4.7 ± 1.0 µkat/l). Concentrations of potassium at eleven months (8.3 ± 2.1 mmol/l) were significantly higher ( P ˂ 0.001) than the mean concentration of potassium at seven months (5.4 ± 1.3 mmol/l) and also at ninth months (6.1 ± 1.6 mmol/l). No significant differences were found among the mean concentrations of total protein (57.5 ± 14.6, 61.9 ± 9.2, 59.6 ± 12.2 g/l), albumin (32.8 ± 5.4, 33.6 ± 4.1, 33.4 ± 7.1 g/l), globulin (27.4 ± 5.4, 26.6 ± 4.3, 26.3 ± 5.4 g/l) and mean activity of creatine kinase (25.4 ± 10.3, 30.1 ± 21.0, 25.6 ±13.2 µkat/l) at any of the ages. In all females, ovarian activity was already evident in the first part of monitoring, and the measured values could be interpreted as values for young female veiled chameleons during active ovarian activity.

Influence of Gender on Total Serum Creatine Kinase and Creatine Kinase-Mb Levels of Nigerian Hypertensives

Introduction: Hypertension is a long-term medical condition which when not detected and managed properly and on time often results to complications leading to disabilities and mortality. Gender has been known to affect the interpretation of some variables necessitating the need for gender-specific ranges.
 Objectives:This study evaluated total creatine kinase (CK) and creatine kinase-MB (CK-MB) isoenzyme activities of hypertensive subjects in Calabar, Nigeria and to assess if gender has influence on the activities of these enzymes.
 Methodology:One hundred and two participants were consecutively enrolled in this case control study. Serum total serum CK and CK-MB activity were evaluated in fifty one hypertensive and 51 normotensive subjects. The total CK levels were assessed using a spectrophotometric method while immunoinhibition method was used to determine the activity of CK-MB. Data was analyzed using Student’s t-test and Pearson’s correlation. Statistical significance was set at p<0.05.
 Results:The total creatine kinase activities of the hypertensives did not differ significantly from those of the normotensive controls (p = 0.428) while the serum CK-MB activities of the hypertensive subjects were significantly higher than those of the normotensive controls (p=0.000). The body mass index of the hypertensives was significantly higher than those of the normotensive subjects (p=0.030). Gender had no effect on the blood pressure, body mass index and levels of CK and CK-MB (p>0.05). There was also no significant correlation (p>0.05) between blood pressure, body mass index and the levels of CK and CK-MB.
 Conclusion:CK-MB activities were significantly higher in hypertensive subjects compared to normotensive controls. There were no gender specific differences in the CK-MB levels of male and female hypertensives. This cardiac marker should be included in the routine assessment of hypertensives and gender-specific considerations may not be necessary in the interpretation of the data.

Elastic resistance training is more effective than vitamin D3 supplementation in reducing oxidative stress and strengthen antioxidant enzymes in healthy men.

ObjectiveToday, reducing oxidative stress and improving the antioxidant system with antioxidant supplements along with exercise training has received a lot of attention. Vitamin D plays a very important role in general health and reducing oxidative stress. The aim of this study was to examine the effect of vitamin D3 supplements during elastic-band resistance training (EBT) on oxidative stress and antioxidant indices in healthy men.MethodsForty healthy men (Serum: 20 ≤ 25 (OH) D ≤ 25 ng/mL) voluntarily participated in the current study and randomly were assigned to EBT-vitamin D3 (ED, n = 10), EBT-placebo (EP, n = 10), vitamin D3 (VD, n = 10), and control (Con, n = 10). EBT was performed three times per week on non-consecutive days for eight weeks, in seven exercises. The subjects in the ED, VD, and EP consumed 50,000 IU vitamin D3 or placebo once every 2 weeks. Ten ccs blood samples were collected before and after exercise training and the total antioxidant capacity (TAC), superoxide dismutase (SOD), glutathione peroxidase (GPX), and creatine kinase (CK) activities were measured in the plasma. Malondialdehyde (MDA), as the lipid peroxidation index, and 25(OH) D were measured in the plasma.ResultsWe found that there was a significant difference between ED with VD (p = 0.011) and Con (p = 0.022) for MDA. A significant difference was also seen for SOD in ED with VD (p = 0.024) and Con (p = 0.038) and TAC in ED with VD (p = 0.020) and Con (p = 0.030), and GPX in ED with VD (p = 0.040) and Con (p = 0.010). While there were no significant differences between ED and EP in all mentioned variables (p > 0.05).ConclusionFinally, it can be said that elastic resistance training improved antioxidant defence. However, vitamin D3 supplementation during resistance elastic training has no synergistic effect on attenuating oxidative stress indices.

Determination Total Creatine Kinase Activity and Creatine Kinase Isoenzymes Activities in Patients with Ulcerative Colitis and Crohn’s Disease under Infliximab Therapy

Creatine kinase (CK) catalyzes the transfer of a phosphate group from creatine phosphate to adenosinediphosphate, and the CK has three isoenzymes CK-MM, CK-MB and CK-BB. Ulcerative colitis (UC) andCrohn’s disease (CD) they are both conditions characterized by long life inflammation of the gastrointestinalsystem. The Purpose of this study was to determine the total CK activity and CK isoenzymes in patientswith Crohn’s Disease and Ulcerative Colitis under Infliximab therapy. For the UC patients, CD patients andcontrols the CK isoenzyme activities and total CK activity was measured, the three CK isoenzymes separateby suitable ion-exchanger small columns (DEAE-Sephadex A-50 exchanger). The results display Creatinekinase isoenzyme chromatograms of all studied groups (UC, CD patients and controls), with variableactivities of (CK-BB) and (CK-MB) isoenzymes with noted an elevation of (CK-MM) isoenzyme activitiesand significantly elevation total CK activity in serum of patient groups after therapy when compared withbefore therapy patient groups.

Subtle Role for Adenylate Kinase 1 in Maintaining Normal Basal Contractile Function and Metabolism in the Murine Heart.

AimsAdenylate kinase 1 (AK1) catalyses the reaction 2ADP ↔ ATP + AMP, extracting extra energy under metabolic stress and promoting energetic homeostasis. We hypothesised that increased AK1 activity would have negligible effects at rest, but protect against ischaemia/reperfusion (I/R) injury.Methods and ResultsCardiac-specific AK1 overexpressing mice (AK1-OE) had 31% higher AK1 activity (P = 0.009), with unchanged total creatine kinase and citrate synthase activities. Male AK1-OE exhibited mild in vivo dysfunction at baseline with lower LV pressure, impaired relaxation, and contractile reserve. LV weight was 19% higher in AK1-OE males due to higher tissue water content in the absence of hypertrophy or fibrosis. AK1-OE hearts had significantly raised creatine, unaltered total adenine nucleotides, and 20% higher AMP levels (P = 0.05), but AMP-activated protein kinase was not activated (P = 0.85). 1H-NMR revealed significant differences in LV metabolite levels compared to wild-type, with aspartate, tyrosine, sphingomyelin, cholesterol all elevated, whereas taurine and triglycerides were significantly lower. Ex vivo global no-flow I/R, caused four-of-seven AK1-OE hearts to develop terminal arrhythmia (cf. zero WT), yet surviving AK1-OE hearts had improved functional recovery. However, AK1-OE did not influence infarct size in vivo and arrhythmias were only observed ex vivo, probably as an artefact of adenine nucleotide loss during cannulation.ConclusionModest elevation of AK1 may improve functional recovery following I/R, but has unexpected impact on LV weight, function and metabolite levels under basal resting conditions, suggesting a more nuanced role for AK1 underpinning myocardial energy homeostasis and not just as a response to stress.

Staging of occupational medicamentosa-like dermatitis due to trichloroethylene

Objective: To explor staging of the general course of occupational medicamentosa-like dermatitis due to trichloroethylene (OMDT) to better understand the characteristics of OMDT course, and to provide reference for clinical diagnosis and treatment and related studies. Methods: We collected main clinical manifestation and auxiliary examination data during hospitalization to May 2019 from 35 OMDT patients with complete course record who were hospitalized from January 2014 to December 2018. Continuous monitoring indicators with changing trends including main clinical manifestation indicators, peripheral white blood cell counts, liver function indicators such as serum alanine aminotransferase activity, myocardial enzyme indicators such as serum lactate dehydrogenase activity were selected and used with their standardized values to do cluster analysis on time point (week as unit) of the course of each patient. The clustering results combined with changing trends of the indicators were used to determine the stages of course of each patient, and therefore the staging of general course of OMDT was calculated. Positive rates or average levels of the indicators were compared between different stages, and the correlation of duration of each stage was analyzed with physical characteristics, disease characteristics and treatment measures of the patients. Results: General course of OMDT could be divided into acute phase (3.0±1.5) weeks and chronic phase (11.0±4.4) weeks, while chronic phase could be further divided into early period (5.0±3.0) weeks and later period (6.5±3.7) weeks. Compared with chronic phase, clinical manifestation indicators, white blood cell counts (except eosinophil count) , liver function indicators (except total protein and albumin concentration) , and myocardial enzyme indicators were all increased (all P<0.01) , while total protein and albumin concentration decreased (P<0.05 and P<0.01, respectively) in acute phase. Compared with later period of the chronic phase, clinical manifestation indicators (except fever) , white blood cell counts (except lymphocyte count) , liver function indicators (except total protein and albumin concentration) , and creatine kinase isoenzyme activity were all increased (all P<0.01) , while total protein, albumin concentration and creatine kinase activity decreased (all P<0.01) . Duration of acute phase were positively correlated with the time before glucocorticoid treatment (r(spearman)=0.62, P(adjust)<0.01) , and early and later periods of chronic phase were both positively correlated with corresponding duration of glucocorticoid treatment (r(spearman)=0.96, P(adjust)<0.01, r(spearman)=0.91, P(adjust)<0.01, respectively) . Conclusion: For the first time, the study objectively determined stages of general course of OMDT based on combination of multiple indicators, and analyzed characteristics of main indicators in each phase and potential factors related to the duration of each phase.

Cardiac Energetics in Patients With Aortic Stenosis and Preserved Versus Reduced Ejection Fraction

Why some but not all patients with severe aortic stenosis (SevAS) develop otherwise unexplained reduced systolic function is unclear. We investigate the hypothesis that reduced creatine kinase (CK) capacity and flux is associated with this transition. We recruited 102 participants to 5 groups: moderate aortic stenosis (ModAS) (n=13), SevAS, left ventricular (LV) ejection fraction ≥55% (SevAS-preserved ejection fraction, n=37), SevAS, LV ejection fraction <55% (SevAS-reduced ejection fraction, n=15), healthy volunteers with nonhypertrophied hearts with normal systolic function (normal healthy volunteer, n=30), and patients with nonhypertrophied, non-pressure-loaded hearts with normal systolic function undergoing cardiac surgery and donating LV biopsy (non-pressure-loaded heart biopsy, n=7). All underwent cardiac magnetic resonance imaging and 31P magnetic resonance spectroscopy for myocardial energetics. LV biopsies (AS and non-pressure-loaded heart biopsy) were analyzed for CK total activity, CK isoforms, citrate synthase activity, and total creatine. Mitochondria-sarcomere diffusion distances were calculated by using serial block-face scanning electron microscopy. In the absence of failure, CK flux was lower in the presence of AS (by 32%, P=0.04), driven primarily by reduction in phosphocreatine/ATP (by 17%, P<0.001), with CK kf unchanged (P=0.46). Although lowest in the SevAS-reduced ejection fraction group, CK flux was not different from the SevAS-preserved ejection fraction group (P>0.99). Accompanying the fall in CK flux, total CK and citrate synthase activities and the absolute activities of mitochondrial-type CK and CK-MM isoforms were also lower (P<0.02, all analyses). Median mitochondria-sarcomere diffusion distances correlated well with CK total activity (r=0.86, P=0.003). Total CK capacity is reduced in SevAS, with median values lowest in those with systolic failure, consistent with reduced energy supply reserve. Despite this, in vivo magnetic resonance spectroscopy measures of resting CK flux suggest that ATP delivery is reduced earlier, at the moderate AS stage, where LV function remains preserved. These findings show that significant energetic impairment is already established in moderate AS and suggest that a fall in CK flux is not by itself a necessary cause of transition to systolic failure. However, because ATP demands increase with AS severity, this could increase susceptibility to systolic failure. As such, targeting CK capacity and flux may be a therapeutic strategy to prevent and treat systolic failure in AS.

The effect of intermittent hypoxic exposure on erythropoietic response and hematological variables in elite athletes.

This study aimed to evaluate the changes in the erythropoietin level and hematological variables in wrestlers after intermittent hypoxic exposure (IHE). Twelve wrestlers were assigned into two groups: hypoxia (sports training combined with IHE, n=6) and control (sports training, n=6). An IHE was performed for 10 days, with one day off after 6 days, once a day for about an hour. The concentrations of hydrogen peroxide ( H(2)O(2) ), nitric oxide (NO), vascular endothelial growth factor (VEGF) and erythropoietin (EPO), as well as total creatine kinase activity (CK) were measured. Also, the hematological markers (Hb - hemoglobin, Ht - hematocrit, RBC - red blood cell, WBC - white blood cell, Ret - reticulocytes) were analyzed. The 6-day IHE caused an increase in the levels of H(2)O(2), NO and VEGF. Similarly, the EPO level and WBC count reached the highest value after 6 days of IHE. The total Ret number increase constantly during 10 days of IHE. The hypoxia group showed a higher CK activity compared to the control. In conclusion, 10-day IHE in combination with wrestling training elevates levels of H(2)O(2), NO and VEGF, and improves the oxygen transport capacity by the release of EPO and Ret in circulation.

Sex Differences in Physiological Stress Induced by a Long-Lasting Adventure Race: A Prospective Observational Analytical Study.

In order to provide additional information on the behaviour of biochemical parameters related to stress responses to a specific long-term competition, we aimed to compare the stressful effects of a long-lasting competition on physiological variables in men and women. This is a prospective observational analytical study. Twenty-five professional athletes, 15 men and 10 women, travelled 460 km for 4 days in an international edition of the Ecomotion/Pro AR World. After the competition, we detected an increase in α-amylase and cortisol levels and a decrease in salivary immunoglobulin A (lgA) levels. The relative percentage changes in α-amylase, IgA and cortisol levels were significantly higher in women than in men, whereas women had lower relative percentage changes in glucose and lactate levels compared with men. There was a decrease in lymphocyte, eosinophil and monocyte counts, with relative percentage decreases in lymphocytes and monocytes being significantly higher in female athletes than in males. There were increases in the serum activities of total creatine kinase (CK), the creatine kinase myocardial isoform (CKMB), alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) at the end of the test, with significantly higher elevations of total CK, CKMB and LDH in men and ALT in women. Long-lasting competition induced stress, muscle damage, anaemia and changes in the immune system. Women had more intense responses of cortisol and leukocytes.

P1611Non-invasive predictors of LV biopsy-obtained creatine kinase activity in patients with non-failing and failing myocardial hypertrophy

Abstract Introduction Myocardial creatine kinase (CK) activity represents an important metabolic reserve: it correlates closely with contractile reserve and post-ischaemic function, keeps cytosolic [ADP] low, and optimises the free energy for ATP hydrolysis. It may also contribute to the transition to failure in the heart hypertrophied by chronic haemodynamic overload; modest up-regulation has been shown to be cardio-protective. Total CK activity measurement requires chemical freeze-and-extract methods, which destroy tissue, precluding repeated measures. To date, non-invasive assessments of human myocardial CK flux (calculated as kf × [PCr], where kf is the pseudo-first-order forward rate constant measured by 31P-magnetic resonance spectroscopy (MRS) have not assessed creatine content or total CK activity. Thus we aimed to validate kf measurement against total CK activity and investigate predictors of CK activity. Methods 39 subjects (median age 71, range 43–84) undergoing clinically indicated cardiac surgery had CK total activity measured from LV biopsy. 31 had severe AS (10 with impaired LVEF); 2 had severe primary MR; 5 had severe mitral stenosis (2 with impaired LVEF) and 1 had an LA mass. 35 of 39 contributed triplicate datasets: CK total activity, kf (31P-MRS TRiST sequence at 3T) and LV volumes (cine-MRI, 3T Siemens). 27 had severe AS (8 with impaired LVEF); other groups were the same. Exclusion criteria were prior myocardial infarction and flow-limiting coronary disease. Flash-frozen LV biopsies obtained within 15 min of cardiopulmonary bypass were analysed for CK total activity, total creatine, and citrate synthase (CS) activity (a marker of oxidative phosphorylation capacity). Results Multiple, novel correlations were observed between CK total activity (IU/mg protein) and CS activity (r=0.87, p=9e-13), total creatine (r=0.59, p=8e-5), kf (r=0.42, p=0.013), total creatine × kf (r=0.64, p=4e-5), LVESVi (r=−0.52, p=8e-4), LVEF (r=0.48, p=0.002) and LVMi (r=−0.42, p=0.009) (Panels A-E) (LVEDVi and non-indexed counterparts were also significant correlates.) The most predictive linear regression model incorporating elements of the CK rate equation included total creatine (nmol/mg protein), kf (/s), and kf × LVESVi (ml/m2) (adjusted R2=0.56, beta=0.426, 0.618, −1.968 and p=0.001, 5e-5, 0.003 respectively, Panel F). Figure 1 Conclusions These results are the first evidence of agreement between non-invasive estimates of human cardiac CK activity (kf) and freeze-extracted chemical methods. The key original finding is that it is feasible to attempt to predict CK capacity in vivo by using a combination of techniques (creatine by 1H MRS, CK kf by 31P-MRS and LVESVi by cine imaging). The key insight is that CK capacity is best estimated not simply from what the rate equation would predict (creatine and kf), but that other factors relating to failing contractility reduce CK activity independently from creatine content and enzyme kf. Acknowledgement/Funding British Heart Foundation Clinical Research Training Fellowship (FS/15/80/31803) and Programme Grant (RG/18/12/34040).

P2272Determinants of left ventricular ATP availability measured in vivo and ex vivo in patients with severe aortic stenosis: correlation of creatine kinase activity with LVEF and ATP diffusion distance

Abstract Introduction The transition to systolic failure in severe aortic stenosis (AS) increases mortality. There are currently no reliable markers of transition, and the guideline LVEF &lt;50% threshold for intervention in asymptomatic severe AS does not capture all subjects at increased risk. In animal models, reduced ATP delivery capacity through creatine kinase (CK) is important, with modest increases in CK capacity conferring cardioprotection. ATP may also diffuse (independent of CK) from mitochondria to the contractile site. We have performed the first human study to test whether ATP diffusion distance relates to CK activity and whether CK activity is reduced in low LVEF severe AS. Methods 19 patients with severe AS, LVEF ≥55% (AS-pEF, mean±SD LVEF 63±5%, mean gradient 48±14 mmHg) and 10 with severe AS, LVEF &lt;55% (AS-rEF, LVEF 42±8%, mean gradient 32±11) underwent 31P-MRS for CK rate constant (kf) and phosphocreatine/ATP (PCr/ATP) ratio, and MRI for LV volumes. LV biopsies were taken during AVR and analysed for CK total activity, CK isoforms, total creatine, and citrate synthase (CS) activity. 9 biopsies also underwent serial block face scanning electron microscopy and mitochondria-sarcomere 3D distance distributions were plotted. Results were compared to 24 controls (LVEF 61±4%), of which 4 had LV biopsy (3 severe MS, 1 LA myxoma, MS-pEF). Surgical patients had flow-limiting atheroma excluded with invasive angiography and prior myocardial infarction excluded with late gadolinium enhancement MRI. Results When compared to controls, both CK total activity and CS activity were lower in AS-pEF (by 27% and 23% respectively, both p&lt;0.05, Panels A-B). Although PCr/ATP reduced in AS-pEF (by 20%, p&lt;0.001, panel C), kf (panel D) and CK flux estimated by kf × total creatine were not different. CK-MB expression reduced in AS-pEF (19 vs 27% of total CK, p=0.003), reflecting compensatory increases in CK-MM (p=0.26) and CK-BB (p=0.18) in the face of reduced CK activity. AS-rEF was associated with further reduction in both CK and CS activities (by 32% and 22% respectively, both p&lt;0.05, Panels A-B), but no differences in PCr/ATP, CK kf or relative CK isozyme expression were seen. There were no significant between-group differences in total creatine (Panel E). Overall this suggests that CK reserve and oxidative capacity potentially reduce in pressure overload, with further falls commensurate with systolic dysfunction. When median mitochondria-sarcomere ATP diffusion distances were plotted against CK total activity a strong positive correlation was observed (r=0.86, p=0.003, Panel F). This suggests a compensatory reduction in diffusion distance develops when CK activity falls. Conclusions Transition to failure in severe AS is associated with lower oxidative capacity and maximal ATP delivery capacity through CK. Despite compensatory falls in ATP diffusion distance and altered CK isozyme expression, these changes may underlie susceptibility to EF decline in AS. Acknowledgement/Funding British Heart Foundation Clinical Research Training Fellowship (FS/15/80/31803) and Programme Grant (RG/18/12/34040).

Analysis of seminal plasma biochemical parameters and sperm cryostability in different age groups of stallions

We studied sperm of stallions of different age groups of the Arab breed at the age of 4 to 21 (n=36). The concentrations of total protein (TP), albumin, globulins, glucose, urea, phospholipids, ionized calcium (Ca2+), and enzyme activity of creatine kinase (CK), alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), amylase, lactate dehydrogenase (LDH) were determined in seminal plasma. After sperm freezing and thawing the progressive sperm motility and viability at +4 °C were studied. We found that progressive motility and viability of spermatozoa after freezing and thawing in stallions at the age of 6-10 years was statistically significantly higher than that of stallions at the age of 4-5 (p=0.004 and p=0.02), 11-15 (p=0.04 and p=0.04) and 16-21 (p=0.01 and p=0.01, respectively). The concentration of sperm in the ejaculates of older stallions (16-21 years old) is significantly lower than in the ejaculates of stallions aged 4-5 (p=0.04), 6-10 (p=0.003), 11-15 (p=0.04). The level of urea in seminal plasma of older stallions (16-21 years old) was statistically significantly higher than in the group of stallions aged 6-10 (p=0.01). There is a negative correlation between progressive sperm motility after cryopreservation and urea concentration in stallion seminal plasma (r=-0.48; p<0.05).

Investigation into the Possible Risk Effects Associated with Drug and Alcohol-induced Gastrointestinal Ulcer in Wistar Albino Rats

Aim: The study investigated the possible risks associated with gastrointestinal ulcer disease by evaluating the biochemical response of three body organs; heart, kidney and liver, in gastric ulcerated rats.&#x0D; Methodology: Twenty male wistar albino rats were used in the study. Gastric ulcer was induced in rats with single oral dose of 400 mg/kg body weight (b.w.) aspirin, 80 mg/kg b.w. indomethacin and 5 ml/kg b.w. acidified ethanol (40:60 v/v). Blood samples were collected into heparinized bottle and centrifuged at 4000 rpm for 10 mins to obtain the plasma. Gastric tissue, liver, kidney and heart were also collected.&#x0D; Results: Oral administration of 400 mg/kg b.w. aspirin, 80 mg/kg b.w. indomethacin and 5 ml/kg b.w. acidified ethanol caused a remarkable increase in ulcer index. There was observed a significant (p&lt;0.05) reduction in AST and ALT activities in gastric ulceration caused by aspirin (Asp), with no significant (p&lt;0.05) change in total protein (TP) concentration, lactate dehydrogenase and creatine kinase activity. However, there was increase in creatinine and urea concentration. Acidified ethanol and Indomethacin-induced ulcerated rats showed significant (p&lt;0.05) reduction in all other parameters except ALT and lactate dehydrogenase activities which did not show any significant (p&lt;0.05) change. There was also observed a significant (p&lt;0.05) increase in creatine kinase activity in indomethacin-induced ulcerated rats.&#x0D; Conclusion: Overall, the result indicates a link between gastric ulcer and organ toxicity. The use of NSAIDs above the therapeutic doses in the treatment of pains and related illness as well as excess consumption of alcohol is shown to negatively impact the stomach and cause serious damage to different body organs of wistar rats.