The effects of beta alanine plus creatine administration on performance during repeated bouts of supramaximal exercise in sedentary men

AIM

The aim of this study was to investigate the effects of beta alanine and/or creatine supplementation on performance during repeated bouts of supramaximal exercise in sedentary men.

METHODS

Forty-four untrained healthy men (aged 20-22 years, weight: 68-72 kg, height: 174-178 cm) participated in the present study. After performing the Wingate Test (WAnT) for three times in the baseline exercise session, the subjects were assigned to one of four treatment groups randomly: 1) placebo (P; 10 g maltodextrose); 2) creatine (Cr; 5 g creatine plus 5 g maltodextrose); 3) beta-alanine (β-ALA; 1,6 g beta alanine plus 8,4 g maltodextrose); and 4) beta-alanine plus creatine (β-ALA+Cr; 1,6 g beta alanine plus 5 g creatine plus 3,4 g maltodextrose). Participants were given the supplements orally twice a day for 22 consecutive days, then four times a day for the following 6 days. After 28 days, the second exercise session was applied during which peak power (PP) and mean power (MP) were measured and fatigue index (FI) was calculated.

RESULTS

PP and MP decreased and FI increased in all groups during exercise before and after the treatment. During the postsupplementation session PP2 and PP3 increased in creatine supplemented group (from 642.7±148.6 to 825.1±205.2 in PP2 and from 522.9±117.5 to 683.0±148.0 in PP3, respectively). However, MP increased in β-ALA+Cr during the postsupplementation compared to presupplementation in all exercise sessions (from 586.2±55.4 to 620.6±49.6 in MP1, from 418.1±37.2 to 478.3±30.3 in MP2 and from 362.0±41.3 to 399.1±3 in MP3, respectively). FI did not change with beta alanine and beta alanine plus creatine supplementation during the postsupplementation exercise session.

CONCLUSION

Beta-alanine and beta alanine plus creatine supplementations have strong performance enhancing effect by increasing mean power and delaying fatigue Index during the repeated WAnT.

Protective effects of curcumin supplementation on intestinal ischemia reperfusion injury

The aim of this study was to investigate the effects curcumin on inflammation and oxidative stress markers in the intestinal ischemia reperfusion (IIR) injury induced rats. Rats were divided into four groups: sham (S), intestinal IR (IIR), curcumin plus sham (CS), and curcumin plus intestinal IR (CIIR). Curcumin was given 200 mg kg⁻¹ for 20 days. IIR was produced by 45 min of intestinal ischemia followed by a 120 min of reperfusion. Although interleukin-6 levels tended to increase in IIR group tumor necrosis factor-α levels were not different. Intestinal myeloperoxidase activity in CS group was lower than IIR group. In intestine and heart tissues, malondialdehyde levels in CS and CIIR groups were lower than S and IIR groups. Superoxide dismutase activity in CIIR group was higher than IIR group in intestine and lung tissues. Curcumin has a protective role against ischemia reperfusion injury.

Effects of CoQ10 supplementation and swimming training on exhaustive exercise-induced oxidative stress in rat heart

This study examined the combined effects of swimming training and coenzyme Q10 (CoQ10) supplementation on exhaustive exercise-induced oxidative stress in rat heart. The study was carried out with 4-month-old young adult male Wistar rats. Sixty four rats were divided mainly into two groups: trained and control. Each group was further divided into four subgroups: rest, exhausted, rest with CoQ10, exhausted with CoQ10. The training program consisted of swimming one hour each day, five days a week, for six weeks. At the end of sixth week, rats in exhausted exercise group were forced to swim until exhaustion and then they were immediately sacrificed, while rats in rest group were sacrificed at rest. Training alone or in combination with CoQ10 supplementation reduced to increasing MDA levels due to exhaustive exercise in rat heart (p<0.05). The trained-rest with CoQ10 group showed lower 8-OHdG levels than the control-rest with CoQ10 group. Exhaustive exercise effect was significant on SOD activity. Exhaustive exercise increased GSH levels in control groups while decreased GSH levels in training groups (p<0.05). In conclusion, the results suggest that CoQ10 supplementation combined with training may inhibit lipid peroxidation and DNA damage in the heart tissue. Also, it can be said that SOD activity and GSH levels were not influenced by CoQ10 supplementation (Fig. 4, Tab. 1, Ref. 69).

Curcumin increases vasodilatory effect of cilostazol in diabetic rat aorta

Increased generation of oxidants and (or) reduced endogenous antioxidant defense mechanisms are associated with the etiology of diabetic vascular complications. The aim of the present study was to evaluate whether curcumin supplementation increases the vasodilatory effect of cilostazol in streptozotocin induced diabetic rat aorta. Cumulative addition of cilostazol caused concentration-dependent relaxations of thoracic aorta rings. The sensitivity and the maximal response to cilostazol were significantly higher in control than those in diabetic animals. Treatment with curcumin in control rats increased the sensitivity to cilostazol. Further, in aortic rings from diabetic rats treated with curcumin, the responses to cilostazol were significantly increased in comparison to the response in aorta from untreated diabetic rats. It can be conclude, that curcumin increases the cilostazol-induced vasodilation in diabetic rat aorta.

Alpha lipoic acid treatment improved endothelium-dependent relaxation in diabetic rat aorta

The aim of this study was to ascertain the effects of α-lipoic acid (ALA) treatment on relaxant responses of acetylcholine (ACh) and isoprenaline (ISO) in aortic rings precontracted with serotonin (5-HT, 10(-6) M) obtained from streptozotocin (STZ)-induced diabetic rats. Diabetes was induced in the rats by 50 mg/kg streptozotocin (STZ) via an intraperitoneal injection. Rat body and aorta weights were measured. The isometric tension to ACh (10(-9)-3×10(-6) M) and ISO (10(-9)-10(-4) M) of 5-HT-precontracted diabetic and non-diabetic rat (control), diabetic-ALA-treated, and ALA-treated aortas, in organ baths were recorded. Six weeks after STZ treatment blood glucose was elevated compared to control rats. In aortic rings from diabetic rats ACh and ISO-induced relaxations were impaired whereas endothelium-independent relaxation to sodium nitroprusside (SNP) was unaffected. ALA (100 mg/kg/day) treatment for 5 weeks enhanced ACh and ISO-induced relaxation in diabetic aortas. This recovering effect was via NO because prevented by incubating the vessels with N(G)-nitro-L-arginine methyl ester (L-NAME, a NOS inhibitor). It may be assumed that ALA treatment in vivo, can protect against impaired vascular responsiveness in STZ-induced diabetic rats.

Oxidative stress and antioxidant defense in plasma after repeated bouts of supramaximal exercise: the effect of coenzyme Q10

AIM

The purpose was to determine the changes of oxidative stress and antioxidant markers in plasma after repeated bouts of supramaximal exercise and the effects of coenzyme Q10 supplementation on these changes.

METHODS

This randomized, double blind, crossover study was composed of two 8-week periods of supplementation with either 100 mg.day(-1) CoQ10 or placebo. Fifteen healthy and sedentary men participated in the study. Five Wingate tests with 2 min rest between tests were performed. Blood samples were collected at rest, immediately after, 15 and 60 min after the fifth Wingate test for oxidative stress (malondialdehyde, nitric oxide, xanthine oxidase and adenosine deaminase) and antioxidant (superoxide dismutase, glutathione peroxidase and uric acid) markers.

RESULTS

At baseline exercise session, malondialdehyde increased 15 and 60 min after the exercise compared to the rest and immediately after the exercise. Malondialdehyde at rest, immediately after and 60 min after the exercise decreased with coenzyme Q10 supplementation when compared to baseline. At baseline exercise session, uric acid increased 15 and 60 min after the exercise when compared to the rest. In conclusion, lipid peroxidation and antioxidant defense increase after repeated short-term supramaximal exercise.

CONCLUSION

Coenzyme Q10 supplementation partially prevents the increase in lipid peroxidation after repeated short-term supramaximal exercise.

The dual effects of leptin on aortic rings with and without endothelium isolated from streptozotocin-induced diabetic rats

The aim of this study was to examine the effects of leptin on aortic rings with and without endothelium isolated from streptozotocin (STZ)-induced diabetic and control rats, and also in the presence of an inhibitor of nitric oxide synthase (NOS). Thoracic aortic rings from 5-week STZ-induced diabetic (50 mg/kg i.p.) and age-matched control Sprague-Dawley rats were mounted in isolated tissue baths. Concentration-response curves to leptin (0.1 pM-1 nM) were constructed under basal tone and after precontraction with 1 microM phenylephrine in the presence or absence of Nomega-nitro-L-arginine methyl ester (L-NAME, 10 microM). Leptin caused a concentration-dependent relaxation of precontracted endothelium-intact aortic rings from control and diabetic rats. Responses to leptin in diabetic aorta were significantly increased compared to those of controls (P < 0.05). EC(50) values for leptin were similar for aortic rings from diabetic and control rats (P > 0.05). L-NAME pretreatment caused complete inhibition of the relaxant responses to leptin in the control aortic rings, while it induced a reduction in these responses in the diabetic rings (P < 0.05). Leptin-induced relaxation was eliminated when the endothelium was denuded. Leptin had no effect on the basal tone of endothelium-intact or -denuded aortic rings from control rats. In diabetic rings, leptin elicited concentration-dependent contractions (P < 0.05). Removal of the endothelium significantly increased the contractile effect of leptin on basal tone in diabetic rings (P < 0.05). The results suggest that leptin may induce vasodilatation by endothelial mechanism(s) other than nitric oxide (NO) release from the endothelium in diabetic aortic rings. On the other hand, leptin causes contractile effects on the basal tone in aorta smooth muscle isolated from STZ-induced diabetic rats. The contractile effect of leptin on basal tone may contribute to the development of hypertension in diabetes.

Treatment with antidepressive drugs improved quality of life in chronic hemodialysis patients

BACKGROUND

Despite some improvements in dialysis therapies, depression still remains an important problem in chronic hemodialysis (HD) patients. In this study, we aimed to investigate the association of depression and its treatment with quality of life (QOL) in HD patients.

PATIENTS AND METHODS

97 HD patients (52 male, 45 female, mean age 55 +/- 16 years) were enrolled. All patients had been dialyzed for more than 6 months. In order to evaluate QOL of the patients, a short form of Medical Outcomes Study (SF-36) was used. Depression was assessed by using Beck Depression Inventory (BDI). Patients who had BDI score > or = 15 were diagnosed as to have depression. Patients with depression received antidepressive treatment (sertralin HCl, 50 mg/day) for an 8-week period. After 8-week antidepressive treatment, all biochemical analysis, SF-36 and BDI were performed again.

RESULTS

40 patients (20 male, 20 female, mean age 56 +/- 14 years) had depression. All parameters related to QOL were significantly decreased in patients with depression as compared to patients without depression. Severity of depression was correlated with QOL parameters. After 8 weeks of treatment, as parallel to changes in BDI, QOL parameters improved in patients with depression.

CONCLUSION

Decrease in QOL, associated with depression and antidepressive treatment, improves QOL in HD patients. Hemodialysis patients should be followed-up closely for presence of depression. Treatment of depression with antidepressive drug regimen would lead to relieve the symptoms related to depression and improvement of QOL in these patients. Antidepressive treatment should be required more often than we prescribe in routine clinical practice now.

The ventilatory anaerobic threshold is related to, but is lower than, the critical power, but does not explain exercise tolerance at this workrate

AIM

The aim of the present study was to investigate the relationships between critical power (CP), maximal aerobic power and the anaerobic threshold and whether exercise time to exhaustion and work at the CP can be used as an index in the determination of endurance.

METHODS

An incremental maximal cycle exercise test was performed on 30 untrained males aged 18-22 years. Lactate analysis was carried out on capillary blood samples at every 2 minutes. From gas exchange parameters and heart rate and lactate values, ventilatory anaerobic thresholds, heart rate deflection point and the onset of blood lactate accumulation were calculated. CP was determined with linear work-time method using 3 loads. The subjects exercised until they could no longer maintain a cadence above 24 rpm at their CP and exercise time to exhaustion was determined.

RESULTS

CP was lower than the power output corresponding to VO2max, higher than the power outputs corresponding to anaerobic threshold. CP was correlated with VO2max and anaerobic threshold. Exercise time to exhaustion and work at CP were not correlated with VO2max and anaerobic threshold.

CONCLUSIONS

Because of the correlations of the CP with VO2max and anaerobic threshold and no correlation of exercise time to exhaustion and work at the CP with these parameters, we conclude that exercise time to exhaustion and work at the CP cannot be used as an index in the determination of endurance.

Evaluation of the association between null genotypes of glutathione-S-transferases and Behcet’s disease

Glutathione S-transferases (GST) play an important role in oxidative stress related syndromes. An imbalance of the oxidant and antioxidant systems is important in the pathogenesis of Behcet's disease (BD). The objective of this study was to evaluate the association of null genotypes of GST-M1 and GST-T1 with BD since some preliminary molecular genetic data were recently published. Ninety-four Turkish BD patients (42 male, 52 female, 37.1+/-10.4 years) and 140 healthy volunteers (70 male, 70 female, 36.8+/-11.7 years) matched for age and gender with the patients as the control group were included in the study. Distributions of GST-M1 and GST-T1 genotypes were determined by multiplexed PCR using three sets of primers for GST-M1, GST-T1, and beta-globulin genes. There was no association between BD and the frequencies of GST-M1 and GST-T1 null genotypes when compared to controls by separate analysis. However, by cross and pooled combination analysis there was a significant association between the frequencies of pooled GSTs with one or both null genotypes in BD and controls. This is the first evidence that the association between the frequencies of GST-M1 and GST-T1 null genotypes and BD might be dependent on the interaction of multiple null allele polymorphisms rather than a single null allele of GST-M1 and GST-T1.

The Relationship Between HRCT and Pulmonary Function in Behcet?s Disease

The purpose of this study was to compare the pulmonary functions in female Behcet's patients with or without pathological pulmonary lesions using high resolution computerized tomography (HRCT). Twenty-nine female patients aged 19-54 yrs and 20 healthy females aged 19-50 yrs (control group) were accepted into the study. HRCT images were taken and according to HRCT patients were divided into HRCT (+) and HRCT (-) groups (18 patients in each). Pulmonary function tests (PFT) through a spirometer were performed and FVC, FEV(1), FEF(25-75%), PEF, VC, RV, FRC, DLCO and DLCO/VA were determined. No statistically significant difference was observed when the PFT values were compared between HRCT (+) and HRCT (-) patients for the obtained results and the percentage of the expected values. When the PFT values were compared for both HRCT (+) and HRCT (-) patients with the control group separately there was no statistical difference between the best values. A statistically low DLCO/VA value was observed between the percentage of the expected values. It is concluded that though there is a pulmonary restriction in Behcet's disease, this restriction has no relation to pulmonary functions. It would be useful to perform pulmonary function tests in the patients with Behcet's disease both with or without any pathological findings in HRCT for obtaining information about pulmonary functions. We suggest that even when the results of the pulmonary function tests are normal, considering some pathological changes in HRCT, HRCT investigations may be useful for following up the disease.

Exercise-induced bronchospasm in nonasthmatic obese and nonobese boys

BACKGROUND

In this study it was aimed to compare the degree and frequency of exercise-induced bronchospasm (EIB) in nonasthmatic obese boys with those in nonasthmatic nonobese boys.

METHODS

PARTICIPANTS

Fifty boys (24 obese and 26 control), aged 11 to 15 years, with no history of asthma or other atopic diseases, took part in the study.

MEASURES

Anthropometric measurements and spirometry were performed at rest and spirometry was repeated at 5 and 15 minutes after an eight-minute submaximal exercise on cycle ergometer.

RESULTS

The falls in ratio of forced expiratory volume in one second (FEV1) to forced vital capacity (FVC) and expiratory rates at 5 and 15 minutes after the exercise were significant in obese boys. Only significant change was the fall in FEV1/FVC at 5th minutes in controls. There was no significant difference between obese group and controls in the number of EIB-positive cases. Pulmonary function changes after the exercise had significant negative correlation with body mass index, subscapular and biceps skinfolds.

CONCLUSIONS

Since the fall in pulmonary function was severe in obese boys and these falls were correlated with body mass index and skinfolds, it is concluded that diagnosis and management of EIB may improve aerobic exercise performance and participation in obese children.

Basal metabolic rates of Turkish women during pregnancy

The purpose of the present study was to investigate the basal metabolic rates (BMRs) of pregnant Turkish women and to compare them with values from other countries. Twenty-four pregnant women (aged 24.8+/-5.7 years) were studied longitudinally from early pregnancy through to the end of pregnancy. BMR values were measured in the 1st, 2nd and 3rd trimesters by indirect calorimetry. While the measured BMR significantly increased (279+/-212 kcal/day between the 1st and 3rd trimesters), no change was found when BMR was expressed per unit of body weight. BMR in the 2nd and 3rd trimesters showed a significant correlation with body weight. The BMR increase in pregnant Turkish women was close to that reported in developed countries, and higher than that reported in developing countries. Knowing the metabolic changes of the pregnant women may contribute to dietary recommendations for them.

A combined method for estimating ventilatory threshold

BACKGROUND

The aims of this study were to compare two new methods (Dmax and CUSUM) for determination of the ventilatory threshold and to examine the consequences of estimation by application of these methods in combination.

METHODS

EXPERIMENTAL DESIGN

a comparative design was used.

SETTING

the study was performed in the Exercise Physiology Laboratory in the Faculty of Medicine, Selçuk University.

PARTICIPANTS

thirty-two untrained males (20.6 +/- 1.2 yrs) performed an incremental exercise test on a cycle ergometer.

INTERVENTIONS

there is no intervention.

MEASURES

ventilatory and gas exchange variables were measured breath-by-breath. The ventilatory thresholds were detected by conventional linear regression, CUSUM, Dmax and combined CUSUM-Dmax methods.

RESULTS

The ventilatory thresholds determined by Dmax method gave the highest r-values compared to the criterion method. There was no statistical difference between thresholds determined by all methods or by the same method using different variables. Ventilatory thresholds could not be determined by the conventional linear regression method in three subjects but were determined in all subjects by the other three methods.

CONCLUSIONS

Although all methods presented in this study can be used in the determination of ventilatory threshold, the Dmax method was found to be the most valid one. When using the CUSUM method, combining it with the Dmax method increases the validity of the measurement.

Comparison of the aerobic contributions to Wingate anaerobic tests performed with two different loads

BACKGROUND

The purpose of the present study was to compare the aerobic contribution of the Wingate anaerobic test by increasing the test load and power output.

METHODS

SETTING

The study was performed in the Physiology Department of the Faculty of Medicine, Selçuk University.

PARTICIPANTS

Thirty sedentary male university students volunteered to this study.

EXPERIMENTS

The subjects performed two Wingate tests against resistance of 75 g.kg-1 and 95 g.kg-1 body weight on Monark 818E bicycle ergometer. Breath-by-breath oxygen consumption rates were measured using an automated metabolic measurement chart (Sensormedics 2900). Aerobic contribution was determined by dividing energy equivalence of net oxygen consumption to the total work.

RESULTS

The mean total work values obtained from tests performed at 75 g.kg-1 and 95 g.kg-1 loads were 13.9 +/- 1.5 kjoules and 14.5 +/- 1.8 kjoules (t = 2.32, p = 0.03). Mean total oxygen consumptions were 765 +/- 105 ml and 770 +/- 110 ml, respectively (t = 0.24, p = 0.81). Assuming 20% mechanical efficiency for both tests, aerobic contributions were calculated as 19.5 +/- 3.7% and 18.9 +/- 3.7%, respectively (t = 1.01, p = 0.30).

CONCLUSIONS

Although the power outputs of the two tests were different, the difference between aerobic contributions was not statistically significant. So, it was failed to say that the increase in the power outputs might be related to higher contribution of anaerobic processes. However, if different mechanical efficiencies could be used, relationship between aerobic contributions of two tests might have been different.

Pulmonary function of workers in the aluminum industry

The effects of aluminum on the pulmonary function of aluminum workers were investigated in this study. Serum aluminum levels and spirometry were measured in 55 male workers and 30 male controls. The mean serum aluminum level of workers (72.7 +/- 9.9 ng/ml) was significantly high compared to that of controls, indicating aluminum toxicity. Spirometric parameters were significantly lower in workers than in controls and correlated negatively with both exposure time and serum aluminum levels. The impairment in pulmonary function may be due to exposure time and insufficient protection.

The effects of rHuEPO administration on pulmonary functions in haemodialysis patients

The aim of this study was to investigate the effects of erythropoietin therapy on pulmonary functions in haemodialysis patients. Thirteen patients with chronic renal failure on regular haemodialysis and in need of treatment for anaemia were treated with 45-60 U/kg erythropoietin three times a week. Thirteen haemodialysis patients constituted the control group. Patients receiving erythropoietin were given pulmonary function tests prior to the treatment and after Hb levels had reached 10 g/dl. The interval between first and second pulmonary function tests was similar for both the control group and the erythropoietin group. There was no significant difference between the results of the first and the second pulmonary function tests of the control group. However, in the erythropoietin group, the diffusing capacity, maximal voluntary ventilation, forced vital capacity and peak expiratory flow rate values increased significantly. The existence of a relationship between the diffusing capacity and anaemia is well known. Rises in other parameters following erythropoietin administration might be the result of a gain in respiratory muscle strength consequent to anaemia correction.

Determination of the heart rate deflection point by the Dmax method

OBJECTIVE

Conconi et al. proposed that the point where heart rate departed from linearity in an incremental exercise test was a good indicator of the anaerobic threshold. However, the heart rate deflection points (HRDPs) can not be determined in many subjects. The aim of this study was to determine the heart rate deflection point by the Dmax method and to compare it with the conventional linear method.

SETTING

The study was performed in the Exercise Physiology Laboratory in the Faculty of Medicine, Selçuk University.

PARTICIPANTS

Thirty-two untrained males (aged 18-22) performed a maximal exercise test on a cycle ergometer.

RESULTS

The deflection from linearity of HR could not be detected in nine subjects (28%) by the linear method. The HRDPs could be detected in all subjects by the Dmax method. It was observed that the HR values in the HRDPs determined by both methods were close to the maximal HR values (approximately 90% of maximum). There were high correlations and no differences (p more than 0.05) between the deflection points expressed as oxygen uptake, HR and work rate determined by two methods (correlation coefficients 0.93, 0.93, 0.97, respectively, p less than 0.001).

CONCLUSIONS

The Dmax method is more useful than linear method. The HRDPs of all the people can easily and objectively be found by this method.