Theodore Tsakiris

Evidence for the participation of the stimulated sympathetic nervous system in the regulation of carnitine blood levels of soccer players during a game

Catecholamines and carnitine blood levels are closely implicated with training. The aim of the study was to investigate the effect of sympathetic nervous system stimulation on carnitine and its fraction levels during training. Blood was obtained from 14 soccer players pregame, at intermission, and postgame. Catecholamines were measured with high-performance liquid chromatography methods; muscle enzymes creatine kinase and lactate dehydrogenase as well as lactate, pyruvate, and total antioxidant status with commercial kits; and carnitine and fraction levels with tandem mass spectrometry. Total antioxidant status (2.97 +/- 0.13 vs 0.96 +/- 0.10 mmol/L, P < .01) as well as free carnitine levels (20.47 +/- 4.0 vs 12.30 +/- 2.8 micromol/L, P < .001) were remarkably decreased especially postgame. Total acylcarnitines (5.20 +/- 1.8 vs 9.42 +/- 3.0 micromol/L, P < .001) and especially total very long-chain acylcarnitines (0.80 +/- 0.01 vs 1.85 +/- 0.03 micromol/L, P < .001) as well as catecholamine levels (adrenaline: 230 +/- 31 vs 890 +/- 110 pmol/L, P < .01; noradrenaline: 1.53 +/- 0.41 vs 3.7 +/- 0.6 nmol/L, P < .01) were significantly increased in players postgame. A statistically significant inverse correlation was found between adrenaline and free carnitine (r = -0.51, P < .01); and a positive correlation was found between adrenaline, total acylcarnitines (r = 0.58, P < .01), and total long-chain acylcarnitine (r = 0.49, P < .01). The significant positive correlation of adrenaline levels with total acylcarnitine and total long-chain acylcarnitine blood levels in athletes as well as the inverse correlation with free carnitine levels may indicate participation of the stimulated sympathetic nervous system in the regulation of some carnitine fraction levels during exercise.

alpha-tocopherol supplementation reduces the elevated 8-hydroxy-2-deoxyguanosine blood levels induced by training in basketball players.

Abstract Background: The aim of the present study was to investigate the effect of α-tocopherol (α-Te) supplementation on DNA oxidative damage induced by heavy training in basketball players. Methods: Blood was obtained from 10 players before (group A) and after training (group B) and after 1month on α-Te (200mg/day, orally) supplementation, before (group C) and after training (group D). Total antioxidant status (TAS), muscle enzyme activities and the biomarker of DNA oxidation, 8-hydroxy-2-deoxyguanosine (8-OHdG), were measured using commercial kits. α-Te and catecholamine blood levels were determined using HPLC methods. Results: TAS was higher in the groups with α-Te (groups C and D). Levels of 8-OHdG and muscle creatine kinase (CK) and lactate dehydrogenase (LDH) were remarkably lower (0.20±0.03ng/mL, 120±15 U/L and 430±90U/L, respectively) in the group with α-Te (group D) than in group B (0.42±0.05ng/mL, 286±12U/L and 688±88U/L, respectively; p<0.001). 8-OHdG levels were negatively correlated to TAS and positively to CK levels. Conclusions: α-Te supplementation may reduce DNA oxidation induced by training by protecting muscle cell “death” from glutamate entry and/or by elevation of TAS via amelioration of lipid peroxidation. Clin Chem Lab Med 2006;44:1004–8.

Erythrocyte membrane acetylcholinesterase activity in subjects with MTHFR 677C→T genotype

Abstract Background: Increased homocysteine (Hcy) blood levels are correlated with vascular and neurological problems. Aim: The aim of the present study was to investigate erythrocyte membrane acetylcholinesterase (AChE) activity in subjects with the MTHFR C677T genotype in relation to Hcy. Methods: Blood was obtained from 22 individuals with the MTHFR C677T genotype before and after folic acid supplementation and once from controls (n=30). Plasma folate, vitamin B12 and total antioxidant status (TAS) were measured with commercial kits, Hcy by a HPLC method and membrane enzyme activity spectrophotometrically. Results: In MTHFR C677T carriers, AChE activity was significantly higher (4.20±0.12 × mg protein) and decreased to normal levels (3.14±0.10 × mg protein; p<0.001) after therapy. TAS differed slightly before and after treatment. Hcy levels were significantly higher before (22.4±2.8μM) compared to after (12.1±2.0μM; p<0.001) therapy and compared to controls (10.5±2.5μmol/L; p<0.001). In an in vitro study, incubation of Hcy-activated membrane AChE from controls with phenylalanine resulted in restoration of activity, but failed to reverse the stimulated enzyme from hyperhomocysteinaemic MTHFR C677T subjects before therapy. Alanine incubation protected the enzyme from Hcy activation in controls. Conclusions: Increased membrane AChE activity may be due to high Hcy levels. In vitro, phenylalanine reversed the Hcy activation of the membrane enzyme from controls and alanine protected it from Hcy action.

Thucydides and Strategy: Formations of Grand Strategy in the History of the Second Peloponnesian War (431–404 B.C.) 1

No ancient scholar made a larger contribution to both the theoretical and practical understanding of grand strategy than did the Athenian historian Thucydides the Alimousian. This paper reconstructs the historical context of his History by analyzing it through the multidisciplinary lenses of strategic theory. It highlights the basic “bones of contention” in the historical debate of the last 150 years concerning the causes of the war; the systemic and bilateral balance of power; the political, economic, military and diplomatic parameters that influenced its outcome; and the efficiency of the major alternative strategies followed by Athens and its main adversaries throughout the duration of the conflict.

Significant reduction of erythrocyte glucose-6-phosphate dehydrogenase activity in soccer-players during play. Evidence for catecholamine mediated enzyme inhibition.

We previously reported that mild reductions in erythrocyte glucose-6-phosphate dehydrogenase (G6PD) activity normally induced by training of basketball players was prevented by the administration of the antioxidants L-cysteine or a-tocopherol (1, 2). Because high catecholamine concentrations are reported to contribute to total antioxidant status (TAS) (3), and since G6PD activity is closely related to oxidative stress, we investigated enzyme activity in soccer players at the intermission and post-game in relation to their TAS and blood catecholamine concentrations. This study was approved by the Greek Ethical Committee as amended in 1989. Fourteen, 20-year-old soccer players who were actively participating in the Greek Soccer Championship volunteered to participate. They had trained for at least two years, consisting of two to three 60-min sessions per week, for nine months each year. A championship game took place on a 60 m=40 m pitch. Each team was comprised of seven players; two forwards, two mildfielders, two defenders and one goalkeeper. To ensure similar technical ability between each team, opponents were chosen with a similar league position to the ‘‘experimental’’ team. Clinical and biochemical blood parameters were assessed pre-game (3–4 min prior to start), at the beginning of half-time and at the end of the game (within 3–4 min post-game). Capillary blood samples were obtained from the left thumb for ana-