Melatonin ameliorates cardiac remodelling in fructose-induced metabolic syndrome rat model by using genes encoding cardiac potassium ion channels.

BACKGROUND: Metabolic syndrome comprises a group of disorders, including cardiac abnormalities. Ventricular arrhythmias observed in metabolic syndrome are due to the impaired ventricular repolarization. This study aims to determine the effects of melatonin on cardiac ventricular repolarization in metabolic syndrome rat model. METHODS AND RESULTS: Sprague-Dawley rats were divided into control (n = 8), melatonin (n = 8), metabolic syndrome (n = 8) and metabolic syndrome + melatonin (n = 8) groups. Fructose (200 g/lt/day) was added into the drinking water during 8 weeks of rats to induce metabolic syndrome model. In the last two weeks, melatonin (20 mg/kg/day) was administered via oral gavage. Blood pressure measurements and ECG recordings were taken at three different times. Blood and left ventricular tissue samples were harvested and the KCNQ1,3 and KCNH2 gene expressions were analysed by qRT-PCR method. We observed insulin resistance, hyperglycemia, dyslipidemia and higher systolic blood pressure in metabolic syndrome group (p < 0.01, for all). Prolonged QT interval was observed in metabolic syndrome group (p < 0.001). The expression levels of the KCNQ genes encoding the Kv7 channel was significantly reduced, however KCNH2 gene which encodes Kv11.1 channel was increased in metabolic syndrome group compared to control group (p < 0.05, p < 0.001, respectively). Melatonin significantly normalised the prolongation on QT interval in metabolic syndrome group (p < 0.001) and the expressions of the KCNQ (p < 0.002) and KCNH2 genes (p = 0.003). CONCLUSIONS: The present study revealed that melatonin had ameliorative effects on ventricular repolarization by improving the prolonged QT duration in rats with metabolic syndrome and this effect was generated by the KCNQ and KCNH2 gene families.

The Effect of a High-Protein Diet and Exercise on Cardiac AQP7 and GLUT4 Gene Expression.

High-protein (HP) diets are commonly consumed by athletes despite their potential health hazard, which is postulated to enforce a negative effect on bone and renal health. However, its effects on heart have not been known yet. Aquaporin-7 (AQP7) is an aquaglyceroporin that facilitates glycerol and water transport. Glycerol is an important cardiac energy production substrate, especially during exercise, in conjunction with fatty acids and glucose. Glucose transporter 4 (GLUT4) is an insulin-sensitive glucose transporter in heart. We aimed to investigate the effect of HPD on AQP7 and GLUT4 levels in the rat heart subjected to exercise. Male Sprague-Dawley rats were divided into control (n = 12), exercise (E) training (n = 10), HPD (n = 12), and HPD-E training (n = 9) groups. The HPD groups were fed a 45 % protein-containing diet 5 weeks. The HPD-E and E groups were performed the treadmill exercise during the 5-week study period. Real-time polymerase chain reaction and immunohistochemistry techniques were used to determine the gene expression and localization of AQP7 and GLUT4 in heart tissue. Results of relative gene expression were calculated by the 'Pfaffl' mathematical method using the REST program. Differences in AQP7 and GLUT4 gene expression were expressed as fold change compared to the control group. Heart weight/tibia ratio and ventricular wall thickness were evaluated as markers of cardiac hypertrophy. Further, serum glucose, glycerol, and insulin levels were also measured. AQP7 gene expression was found to be increased in the E (3.47-fold, p < 0.001), HPD (5.59-fold, p < 0.001), and HPD-E (3.87-fold, p < 0.001) groups compared to the control group. AQP7 protein expression was also increased in the HPD and HPD-E groups (p < 0.001). Additionally, cardiac mRNA expression levels of GLUT4 showed a significant increase in the E (2.16-fold, p < 0.003), HPD (7.14-fold, p < 0.001), and HPD-E (3.43-fold, p < 0.001) groups compared to the control group. GLUT4 protein expression was significantly increased in the E, HPD, and HPD-E groups compared to the control group (p = 0.024, p < 0.001, and p < 0.001, respectively). Furthermore, Serum glucose levels were significantly different between groups (p < 0.005). This difference was observed between the HPD groups and normal-protein diet groups (C and E). Serum insulin levels were higher for HPD groups compared with the normal-protein diet groups (p < 0.001), whereas no differences were observed between the exercise and sedentary groups (p = 0.111). Serum glycerol levels were significantly increased in the HPD groups compared with control and E groups (p < 0.05 and p < 0.05, respectively). Consumption of HPD supplementation caused the increased effects on AQP7 and GLUT4 expression in rat heart.

The effect of high protein diet and exercise on irisin, eNOS, and iNOS expressions in kidney.

Long-term effects of high protein diets (HPDs) on kidneys are still not sufficiently studied. Irisin which increases oxygen consumption and thermogenesis in white fat cells was shown in skeletal muscles and many tissues. Nitric oxide synthases (NOS) are a family of enzymes catalyzing the production of nitric oxide (NO) from L-arginine. We aimed to investigate the effects of HPD, irisin and NO expression in kidney and relation of them with exercise and among themselves. Animals were grouped as control, exercise, HPD and exercise combined with HPD (exercise-HPD). Rats were kept on a HPD for 5 weeks and an exercise program was given them as 5 exercise and 2 rest days per week exercising on a treadmill with increasing speed and angle. In our study, while HPD group had similar total antioxidant capacity (TAC) levels with control group, exercise and exercise-HPD groups had lower levels (p < 0.05). Kidneys of exercising rats had no change in irisin or eNOS expression but their iNOS expression had increased (p < 0.001). HPD-E group has not been observed to cause kidney damage and not have a significant effect on rat kidney irisin, eNOS, or iNOS expression. Localization of irisin, eNOS, and iNOS staining in kidney is highly selective and quite clear in this study. Effects of exercise and HPD on kidney should be evaluated with different exercise protocols and contents of the diet. Irisin, eNOS, and iNOS staining localizations should be supported with various research studies.

The comparison of endothelial function of moderate intensity interval exercise with continuous exercise in healthy men.

Background/aim: Exercise enhances endothelium-dependent vasodilation; however, it is unclear whether intermittent exercise has a different effect on vascular endothelial function compared to continuous exercise. This study aimed to compare vascular endothelial function following intermittent exercise including short rest intervals with continuous exercise, both at the anaerobic threshold level. Materials and methods: Peak oxygen consumption (VO2 peak) and anaerobic threshold were measured in physically active healthy young men (n = 12) by breath-by-breath analysis. After completion of intermittent exercise consisting of eight 1-min long intervals at the anaerobic threshold intensity with 75-s rest periods, total work was calculated. Equivalent work was done during continuous exercise. Immediately after the two exercise periods, venous blood lactate, endothelial nitric oxide synthase (eNOS), endothelin-1, N-terminal proANP (NTproANP), N-terminal proBNP (NTproBNP), and N-terminal proCNP (NTproCNP) levels were measured. Brachial artery flow-mediated dilatation (FMD) was measured before exercise and 30 min after exercise. Results: Mean VO2 peak level was 33.42 ± 5.9 ml/min/kg and anaerobic threshold level was 47.33 ± 5.85%. Lactate levels following continuous exercise were higher than levels following intermittent exercise (27.76 ± 7.43 mg/dl, 18.54 ± 4.87 mg/dl respectively; p˂0.05). Endothelin-1, eNOS, NTproANP, NTproBNP, and NTproCNP levels were similar after both modalities of exercise (p > 0.05). No significant difference was found in FMD response when comparing intermittent and continuous exercise (7.05 ± 15.11%, 2.49 ± 16.24% respectively; p > 0.05). Conclusion: Since blood lactate levels are higher following continuous exercise, individuals who find difficulty exercising may prefer an intermittent form of exercise. However, both intermittent and continuous exercise at the anaerobic threshold level seem to not produce a significant acute change in endothelial function in healthy men.

Evaluation of the Effects of High Intensity Interval Training on Cytokine Levels and Clinical Course in Treatment of Opioid Use Disorder. / Opioid Kullanim BozukluguTedavisinde Yüksek Yogunluklu Aralikli Egzersizin Sitokin Düzeyleri ve Klinik Seyir Üzerine Etkileri.

OBJECTIVE: Opioid use disorder (OpUD) is a biological and psychosocial disorder with limited treatment options. Addition of physical exercise to the pharmacological treatment has been proposed to be effective on reducing substance use and improving the quality of life. In this study we aimed to investigate the effects of a high-intensity interval training (HIIT) program on the serum levels of cortisol, insulin-like growth factor1 (IGF-1), interferon-gamma (IFN-γ), interleukin 17 (IL-17) and the clinical progress of inpatients with OpUD. METHOD: Our study enrolled 22 male inpatients diagnosed with OpUD on the basis of the DSM-5 criteria. Two groups of 11 individuals were formed as the exercise (EG) and the control (CG) groups. The EG conducted 5 sessions of a HIIT. Participant data were collected with Sociodemographic Questionnaire, the Addiction Profile Index (API), and the Barratt Impulsiveness Scale (BIS-11). Also, the Hamilton Depression Rating Scale (HAM-D), the Hamilton Anxiety Rating Scale (HAM-A) and the Substance Craving Scale (SCS) were used before and after the treatment program in order to evaluate the clinical progress. Blood samples were collected on the 5th and the 21st days for estimation of the serum cortisol, IGF-1, IFN-γ and the IL-17 levels. RESULTS: Comparison of the pre- and the post- treatment performances of the two groups on the HAM-D, the HAM-A and the SCS indicated a significant drop in the respective scores of the EG. Also, a significant increase was observed in the post-treatment IGF-1 level of the EG as compared to the CG. No differences were observed between the cortisol, IFN-γ and IL-17 levels of the EG and the CG. CONCLUSION: HIIT resulted in significant reduction in the symptoms of depression, anxiety and substance craving, and increased the serum IGF-1 levels. HIIT did not change serum cortisol, IFN-γ and IL-17 levels. We believe this research will contribute to the literature on the treatment of opioid depencence by emphasising the effects of HIIT on patients treated for OpUD.

Alteration in cardiac PI3K/Akt/mTOR and ERK signaling pathways with the use of growth hormone and swimming, and the roles of miR21 and miR133.

Athletes misuse recombinant human growth hormone (r-hGH) to enhance their performance. Although r-hGH is known to increase cardiac hypertrophy, the underlying molecular mechanism remains unclear. The aim of the present study was to investigate the role of r-hGH in cardiac intracellular signaling pathways and of miR-21 and miR-133 expression in rat hearts during exercise. A total of 36 adult male Sprague-Dawley rats were divided into sedentary control (SC, n=9), swimming exercise (SE, n=8), r-hGH (GH, n=10) and swimming exercise plus r-hGH (SE-GH, n=9) groups. The exercise groups completed a 1-h swimming exercise 5 times a week for 8 weeks. Subcutaneous r-hGH was administered as 0.3 mg/kg/day. Phosphoinositide-3-kinase (PI3K), serine/threonine protein kinase 1 (AKT1), extracellular signal-regulated kinase (ERK), microRNA (miR)-21 and miR-133 expression was evaluated in ventricular muscle by real-time quantitative polymerase chain reaction. Protein expression of PI3K, AKT1, ERK and mechanistic target of rapamycin (mTOR) was also assessed by immunohistochemistry. Statistical differences were analyzed by two-way ANOVA. PI3K and AKT1 expression and the gene and protein levels was notably increased in the SE-GH group compared with in SC ventricular tissues (P<0.05). mTOR protein expression was higher in the GH, SE and SE-GH groups compared with in the SC group (P<0.05, <0.05 and <0.001, respectively). ERK gene/protein expression was similar across all groups. miR-21 and miR-133 levels in ventricular muscle were higher in the SE and GH groups than those in the SC group. In summary, growth hormone application coupled with swimming exercise appeared to affect the PI3K/AKT/mTOR signaling pathway in the left ventricular tissue of rats; however, ERK signaling pathway appeared inactive in physiological left ventricular hypertrophy caused by swimming and GH administration over 8 weeks. Furthermore, GH treatment resulted in increased miR-21 and miR-133 expression. Future study by our group will aim to assess the effects of higher dose GH treatment.

High-intensity interval training acutely alters plasma adipokine levels in young overweight/obese women.

The aim of this study was to investigate the plasma adipokine responses to high-intensity interval training (HIT) in overweight/obese women. Twelve women (age 21.7 ± 3.8 years) completed a 19 days of HIT comprising six session of 4-6 repeats of a Wingate test (0.065 kg load/kg). Plasma adipokine levels were measured before exercise, and at 5 and 90 min after exercise on the first and the last training days. Adiponectin was higher at 5 min than 90 min post-exercise (11.7 ± 7.3 and 10.5 ± 5.8 ng/ml; p = .01) in the first exercise day. Leptin decreased 5 min after exercise (23.6 ± 13.2 vs. baseline 27.8 ± 14.4 ng/ml; p < .01) and remained depressed following 90 min (p < .01). The changes in adiponectin and leptin concentrations were similar on the first and last exercise days. No consistent effect was found on resistin concentration. Future studies are required to disclose the functional consequences of these alterations in plasma adipokine levels.

Effects of sleep deprivation on anaerobic exercise-induced changes in auditory brainstem evoked potentials.

BACKGROUND: The present study was designed to assess how anaerobic exercise affects auditory brainstem response (ABR) parameters, and whether one night of sleep deprivation could alter these possible exercise-induced changes in ABRs. METHODS: Seven healthy, audiologically normal male students (mean age 22.4 +/- 1.0 years) participated in the study. All subjects underwent anaerobic Wingate test for three times: (i) baseline, (ii) following a full-night of habitual sleep and (iii) following one night of sleep deprivation. ABR measurements were performed before and after the second and the third Wingate tests. Oral body temperatures were recorded at the beginning of all ABR measurements. RESULTS: The latencies of wave III and V significantly shortened by anaerobic loading performed in the day after habitual sleep (4.13 +/- 0.10 versus 4.01 +/- 0.17 ms, P<0.02; and 5.84 +/- 0.26 versus 5.65 +/- 0.23 ms, P<0.03, respectively). One night of total sleep deprivation shortened pre-exercise latencies and altered exercise-induced changes in ABRs. CONCLUSION: The findings obtained in the present study show that acute anaerobic exercise is effective on ABR wave latencies independent from body temperature changes, and sleep deprivation has some modulatory effects on exercise-induced changes in ABR.

Anxiety of young female athletes with disordered eating behaviors.

The aim of this study was to investigate the prevalence rate of disordered eating behaviors in young female athletes and to compare the anxiety levels of the athletes with or without disordered eating behaviors. Female athletes (n=243) of 15 to 25 years old from the city, Edirne, in Turkey participated our study. Disordered eating behaviors and anxiety levels of participants were evaluated by the Eating Attitudes Test (EAT-40) and State-Trait Anxiety Inventory. Disordered eating behaviors was reported as 40 (16.7%) among all athletes. Both state and trait anxiety scores were higher in athletes with disordered eating behaviors than the athletes without disordered eating behaviors (p=0.01). The athletes who engage in leanness and non leanness sports were reported as having similar EAT-40 scores and anxiety scores. In conclusion, athletes with disordered eating behaviors have higher state and trait anxiety scores.

The relationship between body composition and anaerobic performance of elite young wrestlers.

UNLABELLED: The purpose of the present study was to investigate the relationship between body composition and anaerobic performance in young elite wrestlers. METHOD: Eight female (age = 16.2 ± 1.1 yrs) and 8 male (age = 17.3 ± 0.9 yrs) wrestlers from the Turkish cadet and junior national team participated in this study. Fat free mass (FFM) and percent fat mass (%FM) were carried out through electric bioimpedance. Anaerobic performance was assessed by the Wingate test (load was calculated as 0.090 kg x.kg(-1) body mass). FFM was greater in male wrestlers [65.4 ± 12.3 (kg)] than female wrestlers (45.1 ± 4.6 (kg) p < 0.01). %FM was lower in male wrestlers (9.7 ± 6.3) than female wrestlers (18.5 ± 2.8; p < 0.01). Peak power was significantly higher in male wrestlers than female wrestlers (8.5 ± 1.0 W·kg(-1) vs. 6.8 ± 0.6 W·kg(-1); p < 0.01). Mean power was significantly correlated with FFM in both genders (r = 0.73 p < 0.05 in female; r= 0.90 p < 0.05 in male). No relationship was obtained between anaerobic parameters and %FM. In conclusion, our result demonstrated no association between anaerobic parameters and %FM. Wrestlers and their coaches should take into account FFM rather than %FM for higher anaerobic performance. Key pointsMean power and fat free mass association was obtained from both genders.Anaerobic performance parameters obtained from Wingate Test were positively associated with fat free mass but not % fat mass in elite young wrestlers.% FM values were 18.5 in young female wrestlers, and it was 9.7 in male wrestlers.

Sleep deprivation induced anxiety and anaerobic performance.

The aim of this study was to investigate the effects of sleep deprivation induced anxiety on anaerobic performance. Thirteen volunteer male physical education students completed the Turkish version of State Anxiety Inventory and performed Wingate anaerobic test for three times: (1) following a full-night of habitual sleep (baseline measurements), (2) following 30 hours of sleep deprivation, and (3) following partial-night sleep deprivation. Baseline measurements were performed the day before total sleep deprivation. Measurements following partial sleep deprivation were made 2 weeks later than total sleep deprivation measurements. State anxiety was measured prior to each Wingate test. The mean state anxiety following total sleep deprivation was higher than the baseline measurement (44.9 ± 12.9 vs. 27.6 ± 4.2, respectively, p = 0.02) whereas anaerobic performance parameters remained unchanged. Neither anaerobic parameters nor state anxiety levels were affected by one night partial sleep deprivation. Our results suggest that 30 hours continuous wakefulness may increase anxiety level without impairing anaerobic performance, whereas one night of partial sleep deprivation was ineffective on both state anxiety and anaerobic performance. Key pointsShort time total sleep deprivation (30 hours) increases state anxiety without any competition stress.Anaerobic performance parameters such as peak power, mean power and minimum power may not show a distinctive difference from anaerobic performance in a normal sleep day despite the high anxiety level induced by short time sleep deprivation.Partial sleep deprivation does not affect anxiety level and anaerobic performance of the next day.

High fructose diet suppresses exercise-induced increase in AQP7 expression in the in vivo rat heart.

OBJECTIVE: Cardiac uptake of fructose is thought to be mediated by glucose transporter 5 (GLUT5), whereas the uptake of glycerol is facilitated by aquaporin 7 (AQP7). We aimed to investigate the effect of a high-fructose diet (HFD) on GLUT5 and AQP7 levels in the rat heart subjected to exercise. METHODS: Male Sprague-Dawley rats were allocated to control (C; n=11), exercise (E; n=10), HFD (n=12), and HFD plus exercise (HFD-E; n=12) groups. HFD was started 28 days before euthanasia. From day 24 to 27, rats were subjected to moderate exercise, followed by vigorous exercise on day 28 (groups E and HFD-E). Cardiac GLUT5 and AQP7 mRNA levels were determined using RT-PCR. The protein contents of GLUT5 and AQP7 were immunohistochemically assessed. Paired-t, ANOVA with Bonferroni, Kruskal-Wallis, and Bonferroni-corrected Mann-Whitney U tests were used for statistical analysis. RESULTS: GLUT5 mRNA expression and protein content did not differ between the groups. AQP7 mRNA levels significantly increased (4.8-fold) in group E compared with in group C (p<0.001). Compared with group C, no significant change was observed in AQP7 mRNA levels in groups HFD and HFD-E. The AQP7 staining score in group E was significantly higher than that in groups C (p<0.001), E (p<0.001), and HFD-E (p<0.001). CONCLUSION: Our study indicates that exercise enhances cardiac AQP7 mRNA expression and protein content. However, HFD prevents the exercise-induced increase in cardiac AQP7 expression. This inhibitory effect may be related to the competition between fructose and glycerol as energy substrates in the rat heart subjected to 5 days of physical exercise.

Prevalence of the female athlete triad in edirne, Turkey.

The aim of this study was to determine the prevalence of the female athlete triad, which is a clinical condition defined as the simultaneous occurrence of disordered eating, amenorrhea, and osteopenia and/or osteoporosis in female athletes. A total number of 224 female athletes from Edirne city participated in our study. Eating attitudes test (EAT 40) and a self-administered questionnaire were used to assess disordered eating behavior and menstrual status respectively. The participants having both disordered eating and amenorrhea were performed dual energy x-ray absorptiometry to evaluate bone mineral density. Thirty seven subjects (16.8%) had disordered eating behavior and 22 subjects (9.8%) were reported to have amenorrhea. Six athletes (2.7%) met two criteria (disordered eating and amenorrhea) of the triad. Of these, only three athletes met all components of the triad. We have found that the prevalence rate of female athlete triad was 1.36% among young Turkish female athletes. Female athletes have under considerable risk for the disordered eating and amenorrhea components of the triad. Key PointsThe prevalence rate of the occurrence of whole criteria of the female athlete triad was 1.36 % in young Turkish athletes in Edirne.Female athletes who met whole criteria of female athlete triad are more prone to the eating disorders.The occurrence of disordered eating behavior was higher in female athletes according to general population.Amenorrhea prevalence was significantly higher in female athletes who had disordered eating.

The alteration of NTproCNP plasma levels following anaerobic exercise in physically active young men.

OBJECTIVE: Amino-terminal propeptide of C-type natriuretic peptide (NTproCNP) is a synthesis product of C-type natriuretic peptide (CNP). In this study, plasma levels of NTproCNP were compared before and after exercise in healthy young subjects who are physically active (PA) or not physically active (NPA). METHODS: The study was carried on PA group (n=10) who defined the exercise duration more than 2.5 hours per week for at least one year and NPA group (n = 10) whose exercise duration was lower than 1.5 hours per week. The level of maximal oxygen consumption was determined. Wingate exercise test was applied on the following day. Plasma NTproCNP levels were measured before the exercise and at the 1st, 5th and 30th minute after the exercise. RESULTS: Exercise duration of physically active group was reported as 11.3 ± 5.0 hours per week. Basal NTproCNP levels of the groups were found to be comparable. NTproCNP levels in the 5th minute (0.93 ± 0.23 pmol/L; p<0.05) and in the 30th minute (0.77 ± 0.21 pmol/L p < 0.05) after exercise were higher than the levels before exercise (0.64 ± 0.29 pmol/L) in PA group. Additionally, the plasma levels of NTproCNP after 5th minute of exercise were higher in PA group (0.93 ± 0.23 pmol/L) than NPA group (0.74 ± 0.16 pmol/L, p<0.05). CONCLUSION: Being physically active may be a fact affecting the secretion of CNP, which plays a protective role in endothelium, following exercise.

Hemodynamic effects of atrial natriuretic peptide in ischemia-repertusion injury that occurs after exercise.

BACKGROUND/AIM: Atrial natriureticpeptide (ANP) is known as a protective agent against ischemia-reperfusion injuryfor cardiomyocytes. We compared the hemodynamic effects of ANP and isatin, which is known as an ANP receptor blocker, in ischemia followed by reperfusion in exercised rat hearts with nonexercised ones. MATERIALS AND METHODS: Isolated hearts were perfused in 4 exercised (E) groups after a running protocol for 5 days and 4 nonexercised (NE) groups. In the first protocol, ANP was added to the perfusion solution before ischemia in an E and NE group. In the second protocol, different doses of isatin (0.1, 10, 100 µM/L) were added to the perfusion solution before ANP in 3 E and 3 NE groups. Left ventricular developed pressure (LVDP) and maximum and minimum rates of change in left ventricular pressure (dP/dtmax and dP/dtmin) were recorded. RESULTS: Higher LVDP and dP/dtmin values were observed in the E group than the NE group following addition of ANP before ischemia. Values of dP/dtmax were higher in the E group at the first minute of reperfusion period. Hemodynamic difference was not observed between groups given the same amount of isatin before ANP. CONCLUSION: This study indicated that higher ANP concentrations before ischemia were more effective on the left ventricle contractility and relaxation functions in the hearts that were exposed to exercise.

The alteration of asymmetric dimetilarginine (ADMA) levels in cardiac and gastrocnemius muscles following radioactive iodine application in guinea pigs and the effect of L-carnitine on this alteration.

PURPOSE: Tissue levels of asymmetric dimetilarginine (ADMA) and symmetric dimetilarginine (SDMA) were investigated in cardiac ventricle and gastrocnemius muscles of guinea pigs treated with radioactive iodine (RAI) alone or in combination with L-carnitine (LC). MATERIAL AND METHODS: Group 1 received no treatment (control group). Group 2 received a total dose of 30 mCi⁻¹kg⁻¹ body weight iodine-131 alone. Group 3 received 200 mg⁻¹kg⁻¹ of LC for 10 days alone. Group 4 received 200 mg⁻¹kg⁻¹ of LC plus RAI therapy. Free thyroid hormones, ADMA and SDMA concentrations were measured. RESULTS: Serum free thyroid hormone concentrations were found decreased in the RAI and LC-RAI groups after RAI application. A significant decrease in ADMA and SDMA concentration was observed in ventricle muscle following RAI application. The LC-RAI group had significantly decreased ADMA levels in ventricle muscle compared with those of the control group. Similarly, SDMA concentrations in ventricle and gastrocnemius muscles of the LC-RAI groups were significantly lower than those of the control groups. CONCLUSIONS: Our results indicated that RAI appears to exert an inhibitory effect on ADMA and SDMA levels of ventricular muscle. LC administration when given adjuvant to RAI therapy may cause a marked decrease in ADMA concentrations of both ventricular and gastrocnemius muscles.

Ventricular repolarization in overweight and normal weight healthy young men.

OBJECTIVE: The effects of body mass index (BMI) on ventricular repolarization in young men have not been studied in detail. The QT and JT intervals are measured to estimate the duration of the ventricular repolarization. As new repolarization parameters, the time intervals between the J point to the apex of the T wave (JTa), the apex and the end of T wave (TaTe) may be associated with arrhythmogenesis in clinical conditions. The aim of this study was to compare ventricular repolarization parameters in overweight and normal weight healthy young men. METHODS: Thirty-six overweight men (BMI--26.3+/-1.5 kg/m2, mean age--20.6+/-1.5 years) and 149 men within normal limits (BMI--21.9+/-1.5 kg/m2, mean age--20.4+/-1.4 yrs) were included in this cross-sectional controlled study. The body mass index of 25 to 29.9 kg/m2 was defined as overweight and scores of 18.5 to 24.9 kg/m2 were accepted as normal. Ventricular repolarization parameters including QT, JT, JTa, TaTe, RR intervals duration and heart rate-corrected values of QT (QTc), JT (JTc), JTa (JTac), and TaTe (TaTec) intervals duration were obtained from lead V2 and considered to be representative of the ventricular repolarization process. RESULTS: We found similar ventricular repolarization parameters (QT, JT, JTa, TaTe, RR, QTc, JTc, JTac, and TaTec) in overweight and normal groups. Uncorrected and corrected ventricular repolarization parameters were not correlated with BMI. CONCLUSION: Ventricular repolarization features in young men who are overweight in terms of BMI seem to show no significant difference when compared to normal weight men.

Melatonin administration acutely decreases the diffusing capacity of carbon monoxide in human lungs.

BACKGROUND: Most physiological measurements of the pulmonary diffusing capacity use carbon monoxide (CO) as a tracer gas. Similar to CO, melatonin binds the hemoglobin in the blood. OBJECTIVE: The present study was designed to assess the effect of exogenous melatonin administration on pulmonary functions including diffusing capacity for carbon monoxide (DL(CO)) in healthy subjects. METHODS: The study was performed in a randomized, double-blind, placebo-controlled manner. DL(CO) was measured in 22 healthy male volunteers (age 18-25 years) who were randomized to melatonin (n = 11) and placebo administration (n = 11). At baseline, DL(CO), alveolar volume (V(A)) and other spirometric parameters such as forced expiratory volume in 1 s (FEV(1)), forced vital capacity (FVC), peak expiratory flow (PEF) and maximal voluntary ventilation (MVV) were measured. DL(CO) was then corrected for the hemoglobin concentration. Measurements were repeated in a double-blind fashion 60 min after the administration of melatonin (1 mg) or placebo. RESULTS: DL(CO) was significantly decreased (39.31 +/- 4.75 vs. 34.82 +/- 6.18 ml/min/mm Hg) 60 min after the melatonin administration (p = 0.01), while FEV(1), FVC, FEV(1)/FVC, PEF and MVV values did not demonstrate significant differences. Placebo administration did not result in significant alteration in any of these parameters. CONCLUSIONS: In healthy subjects, oral administration of melatonin acutely influences the DL(CO) without affecting other pulmonary function test results. We conclude that melatonin may have a reducing effect on the DL(CO) in the lungs.