Stylianos Tsakiris's research while affiliated with National and Kapodistrian University of Athens and other places

Publications (147)

Article
Objective: The fetal alcohol spectrum disorder (FASD) is a group of clinical conditions associated with the in utero exposure to ethanol (EtOH). We have recently examined the effects of a moderate maternal exposure to EtOH on crucial brain enzyme activities in offspring rats, and discussed the translational challenges arising when attempting to sim...
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Full-text available
The experimental simulation of conditions falling within "the fetal alcohol spectrum disorder" (FASD) requires the maternal exposure to ethanol (EtOH) during crucial neurodevelopmental periods; EtOH has been linked to a number of neurotoxic effects on the fetus, which are dependent upon the extent and the magnitude of the maternal exposure to EtOH...
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Full-text available
Hyperprolinaemia is characterized by increased tissue accumulation of proline (Pro) and is known to exert serious cognitive and/or neuropsychiatric symptomatology as a direct result of Pro accumulation in the brain. The aim of this study was to explore a putative link between experimentally-simulated hyperprolinaemia and the activity of acetylcholi...
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Abstract Neurodevelopment is known to be particularly susceptible to thyroid hormone insufficiency and can result into extensive structural and functional deficits within the central nervous system (CNS), subsequently leading to the establishment of cognitive impairment and neuropsychiatric symptomatology. The current study evaluated the effects of...
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Thyroid hormone insufficiency during neurodevelopment can result into significant structural and functional changes within the developing central nervous system (CNS), and is associated with the establishment of serious cognitive impairment and neuropsychiatric symptomatology. The aim of the present study was to shed more light on the effects of ge...
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Hypothyroidism is known to exert significant structural and functional changes to the developing central nervous system, and can lead to the establishment of serious mental retardation and neurological problems. The aim of the present study was to shed more light on the effects of gestational and/or lactational maternal exposure to propylthiouracil...
Article
Acetylcholinesterase (AChE) activity is thought to be a major neurotoxicity biomarker. Considering the recently highlighted controversy over the use of AChE activity as a biomarker for the neurotoxicity induced by cadmium (Cd; a major environmental contaminant), we have evaluated the in vitro effects of different concentrations of Cd on AChE activi...
Article
Choline is an essential nutrient, and choline deficiency has been associated with cardiovascular morbidity. Choline is also the precursor of acetylcholine (cholinergic component of the heart's autonomic nervous system), whose levels are regulated by acetylcholinesterase (AChE). Cardiac contraction-relaxation cycles depend on ion gradients establish...
Article
Cholecystokinin (CCK) is a neuropeptide that is (among others) reportedly involved in the pathophysiology of psychiatric disorders. The excitatory role of CCK in negative affective emotions as well as in aversive reactions, antisocial behaviors and memories, has been indicated by numerous electrophysiological, neurochemical and behavioral methodolo...
Article
Cadmium (Cd) is an environmental contaminant known to exert significant neurotoxic effects on both humans and experimental animals. The aim of this study was to shed more light on the effects of gestational (in utero) and lactational maternal exposure to Cd (50 ppm of Cd as Cd-chloride in the drinking water) on crucial brain enzyme activities in im...
Article
Abstract Spontaneous intracerebral hemorrhage (ICH) represents a partially-understood cerebrovascular disease of high incidence, morbidity and mortality. We, herein, report the findings of our study concerning the role of two important adenosinetriphosphatases (ATPases) in a porcine model of spontaneous ICH that we have recently developed (by follo...
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Corresponding author. University of Glasgow, Institute of Cardiovascular and Medical Sciences, College of Medical, Veterinary and Life Sciences, Box 318, 111 West George str., Glasgow G2-1QX, United Kingdom. Fax: +44 141 3304620.
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Full-text available
The conclusion of a series of recent reports highlights the significant neurotoxic effects that rare earth elements, such as lanthanum (La), can have during neurodevelopment. These findings are, herein, combined and presented using a simplified schematic overview that provides a putative solution to the riddle of La-induced cognitive impairment. Ou...
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The present study aimed to shed more light on the effects of gestational (in utero) exposure to cadmium (Cd) on crucial brain enzyme activities of Wistar rat offspring, as well as to assess the potential protective/restorative role that a Cd-free lactation might have on these effects. In contrast to earlier findings of ours regarding the pattern of...
Article
Wernicke's encephalopathy (WE) is a serious neuropsychiatric syndrome caused by chronic alcoholism and thiamine (T) deficiency. Our aim was to shed more light on the pathophysiology of WE, by introducing a modified in vivo experimental model of WE and by focusing on changes provoked in the total antioxidant status (TAS) and three crucial brain enzy...
Article
Gonçalves et al. (2012) recently reported the findings of a long-awaited study on the effects of long-term dietary-induced exposure to cadmium (Cd) on the acetylcholinesterase (AChE) activity of adult rodents' brain regions. Their study can be regarded as a significant contribution to the field, as there is paucity of information on the AChE activi...
Article
Spontaneous intracerebral hemorrhage (ICH) represents a partially-understood cerebrovascular disease of high incidence, morbidity and mortality. We, herein, report the findings of our study concerning the role of two important adenosinetriphosphatases (ATPases) in a porcine model of spontaneous ICH that we have recently developed (by following rece...
Article
Spontaneous intracerebral hemorrhage (ICH) accounts for 10-15% of all strokes. Despite high incidence, morbidity and mortality, the precise pathophysiology of spontaneous ICH is not fully understood, while there is little data concerning the mechanisms that follow the primary insult of the hematoma formation. The cholinergic system, apart from its...
Article
Nickel (Ni) is an environmental pollutant towards which human exposure can be both occupational (mainly through inhalation) and dietary (through water and food chain-induced bioaccumulation). The aim of this study was to investigate the effects of short-term Ni-administration (as NiCl(2), 13 mg/kg) on the adult rat whole brain total antioxidant sta...
Article
Thyroid hormones (THs) exert a broad spectrum of effects on the central nervous system (CNS). Hypothyroidism, especially during CNS development, can lead to structural and functional changes (mostly resulting in mental retardation). The hippocampus is considered as one of the most important CNS structures, while the investigation and understanding...
Article
To investigate erythrocyte membrane AChE, Na(+), K(+)-ATPase and Mg(2+)-ATPase activities in mothers and their full-term or premature newborns in relation to the mode of delivery. Blood was obtained from mothers pre- and post-delivery and the umbilical cord (CB) of their full-term newborns: Group A₁ (n = 16) born with vaginal delivery (VD), Group B...
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Full-text available
Diabetic encephalopathy describes the moderate cognitive deficits, neurophysiological and structural central nervous system changes associated with untreated diabetes. It involves neurotoxic effects such as the generation of oxidative stress, the enhanced formation of advanced glycation end-products, as well as the disturbance of calcium homeostasi...
Article
Choline (Ch) is an essential nutrient that seems to be involved in a wide variety of metabolic reactions and functions that affect the nervous system, while thioacetamide (TAA) is a well-known hepatotoxic agent. The induction of prolonged Ch-deprivation (CD) in rats receiving TAA (through the drinking water) provides an experimental model of mild p...
Article
Forced exercise is associated with oxidative stress, and L-cysteine (L-cys) administration reduces free-radical production. Aim: To investigate whether L-cys (5 mg/kg) intraperitoneal administration can ameliorate modulated total antioxidant status (TAS), protein concentration, and the activities of acetylcholinesterase (AChE), (Na+,K+)-ATPase, and...
Article
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-pe...
Chapter
Inherited metabolic diseases have become a major cause of neonatal pathology, as the classical causes of neonatal distress have been markedly diminished by advances in obstetrical, prenatal, and perinatal management. Their incidence may well be underestimated, since diagnostic errors are frequent. Nevertheless, accurate diagnosis is essential to pr...
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Full-text available
Uncontrolled diabetes is known to affect the nervous system. The aim of this study was to investigate the effect of the antioxidant L: -cysteine (Cys) on the changes caused by adult-onset streptozotocin (STZ)-induced diabetes on the rat brain total antioxidant status (TAS) and the activities of acetylcholinesterase (AChE), (Na(+),K(+))-ATPase and M...
Article
Background: Erythrocyte glucose-6-phosphate dehydrogenase activity (G6PD) is closely related to total antioxidant status (TAS) and forced training to the elevation of catecholamine blood levels. Aim: To investigate the effect of training on G6PD activity in relation to catecholamine levels. Methods: Blood was obtained from 14 soccer players pre-gam...
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Full-text available
Carnitine is an important compound of cellular metabolism and it is essential for b-oxidation of lipid acids. In neural system, although b-oxidation is not the main source of energy, carnitine is involved in the regulation of energy production and calorie intake, the latter via the hypothalamus, as well as indirectly in synaptic neurotransmission....
Article
Choline (Ch) is an essential nutrient that seems to be involved in a wide variety of metabolic reactions and functions that affect the nervous system, while thioacetamide (TAA) is a well-known hepatotoxic agent. The induction of prolonged Ch-deprivation (CD) in rats receiving TAA (through the drinking water) provides an experimental model of mild p...
Article
The aim of this review is to summarize the current data concerning the efficacy and safety of the use of lanthanum (La) in the management of hyperphosphatemia in chronic renal failure (CRF). La is used as a phosphate (P) binder in order to reduce the high levels of the latter that are observed in CRF patients and are associated with secondary hyper...
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Full-text available
Population ageing and modern lifestyle seem to be two important factors contributing to neurodegenerative diseases, while the underlying cellular pathophysiological mechanisms implicate the phenomenon of oxidative stress in most studies. Antioxidants such as carnitine, which neutralize directly or indirectly the action of free radicals, are suggest...
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Full-text available
To investigate the effect of the mode of delivery on maternal-neonatal amino acid levels as high blood levels of some amino acids are implicated with endurance exercise. Comparative study. Thirty women in normal pregnancy divided into two groups: Group A (n=15) with normal labor and vaginal delivery and group B (n=15) with scheduled cesarean sectio...
Article
Choline (Ch) plays an important role in brain neurotransmission, while Ch-deprivation (CD) has been linked to various pathophysiological states. Prolonged ingestion of Ch-deficient diet (CDD) is known to produce CD causing a reduction of rat brain acetylcholine (ACh) levels, as well as memory and growth disorders. The aim of this study was to inves...
Article
Lanthanum (La) is a rare earth element that is widely used for industrial, medical and agricultural purposes. Its neurotoxic effects are linked to its physical and chemical properties and its interaction with certain trace elements and membrane-bound enzymes. The aim of this study was to investigate the effects of short-term La-administration (as L...
Article
Hepatic encephalopathy can be a life-threatening complication of fulminant hepatic failure. By understanding the pathophysiology involved in the induction of this neuropsychiatric disorder, future therapeutic and/or preventive attempts could be considered. In this study, an attempt has been made in order to shed more light on the mechanisms involve...
Article
We investigated the effects of rivastigmine (a cholinesterase inhibitor) and selegiline ((-)deprenyl, an irreversible inhibitor of monoamineoxidase-B), alone and in combination, on brain acetylcholinesterase (AChE), (Na(+), K(+))-, Mg(2+)-ATPase activities, total antioxidant status (TAS), and learning performance, after long-term drug administratio...
Article
Choline is an essential nutrient that seems to be involved in a wide variety of metabolic reactions and functions, that affect the developing brain. The aim of this study was to: (a)examine the effects of early age choline deficient diet (CDD) administration on the total antioxidant status (TAS) and the activities of acetylcholinesterase (AChE), (N...
Article
Manganese (Mn) is an essential metalloenzyme component that in high doses can exert serious oxidative and neurotoxic effects. The aim of this study was to investigate the potential effect of the antioxidant L-cysteine (Cys, 7 mg/kg) on the adult rat brain total antioxidant status (TAS) and the activities of acetylcholinesterase (AChE), Na+,K+-ATPas...
Article
Free radical production and high catecholamine levels are implicated with the modulation of acetylcholinesterase (AChE) activity. To investigate the effect of the mode of delivery on maternal-neonatal erythrocyte membrane AChE activity. Some women with normal pregnancy (N = 30) were divided into two groups: group A (N = 16) with normal labour and v...
Article
Studies have suggested that aspartame (ASP) ingestion is implicated in neurological problems. The aim of this study was to evaluate rat frontal cortex Na+, K+ -ATPase and Mg2+ -ATPase activities after incubation with ASP or each of its metabolites, phenylalanine (Phe), methanol (MeOH) and aspartic acid (asp) separately. Suckling rat frontal cortex...
Article
Free radical production and high catecholamine levels are implicated in the modulation of Na(+), K(+)-ATPase, and Mg(2+)-ATPase activities. The aim of this study was to investigate the effect of the mode of delivery on the above-mentioned enzyme activities in maternal-neonatal erythrocyte membrane. Women with normal pregnancy (N = 30) were divided...
Article
Forced exercise produces free radicals and L-carnitine (L-C) administration reduces oxidative stress. To investigate whether short (2 hours) or prolonged (3 hours) forced swimming could modulate total antioxidant status (TAS), protein concentration and activities of acetylcholinesterase (AChE), Na(+)K(+)-ATPase and Mg(2+)-ATPase in rat brain follow...
Article
Biogenic amine, adrenaline, noradrenaline, dopamine and 5-hydroxy-tryptamine (5-HT) levels are related to interleukin-6 (IL-6) plasma concentrations and endurance exercise. The aim of our study was to investigate the effect of the mode of delivery on maternal-neonatal IL-6, biogenic amine and their precursor amino acid levels. Some women with norma...
Article
Carnitine blood levels are closely related to beta-oxidation and implicated with strenuous muscle contractions. Normal delivery process is characterized by the participation of the uterus and most skeletal muscles. Women with normal pregnancy (n = 56) were divided into two groups. Group A (n = 26) with normal labor and vaginal delivery and group B...
Article
To investigate the effect of a long-distance endurance exercise "Spartathlon" on erythrocyte glucose-6-phosphate dehydrogenase (G(6)PD) activity. The study comprised 15 male runners, median age 36.5 years. Blood samples were obtained in the 15 min before the race and again within 15 min after the end of the race. Erythrocyte glutathione (GSH and GS...
Article
Aim: To investigate the effect of α-Tocopherol (α-T) supplementation on S100B elevated serum levels in basketball players' training. Design: Blood was obtained from 10 basketball players pre-game (group A), post-game (group B) and after 30 days on α-T (200 mg/ 24h orally) supplementation pre-(group C) and post-training (group D). Blood samples were...
Article
The aim of this study was to investigate the effect of the antioxidant L-cysteine (Cys, 7mg/kg) on the changes caused by La-administration (as La-chloride, 53mg/kg) on the adult rat brain total antioxidant status (TAS) and the activities of Na +,K +-ATPase and Mg 2+- ATPase. Twenty-eight male Wistar rats were divided into four groups: A (saline-tre...
Article
We investigated whether the activities of erythrocyte membrane acetylcholinesterase (AChE), Na+, K+-ATPase and Mg2+-ATPase are modulated in basketball players pre- vs. post-forced training with or without L-carnitine (L-C) supplementation. Blood was obtained from 10 male players pre-game (group A) and post-game (group B) and after 1 month L-C suppl...
Article
Aspartame (ASP) consumption is suggested to be implicated with muscarinic dysfunction. The aim of this work was to evaluate the effect of ASP and its metabolites on acetylcholinesterase (AChE) activity in rat frontal cortex and pure enzyme. Rat frontal cortex homogenate or pure enzyme AChE (eel E. Electricus) were incubated with ASP and each of ASP...
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Full-text available
To investigate the effects of diet on the antiatherogenic enzyme Paraoxonase 1/Arylesterase (PON1/Aryl) activities in patients with disorders of galactose metabolism. Eleven poorly dietary controlled children with classical galactosaemia (GALT deficiency), 7 with epimerase deficiency and 12 with duarte 1 variant 'off diet' underwent clinical and la...
Article
Neurological disturbances have been implicated with aspartame (ASP) consumption and the cholinergic system with acetylcholinesterase (AChE) seems actively involved. To evaluate the effect of ASP and its metabolites on rat hippocampal AChE activity. Hippocampal homogenate or pure enzyme AChE (eel E. electricus) was incubated with the sum or each of...
Article
The thyroid hormones (THs) are crucial determinants of normal development and metabolism, especially in the central nervous system. The metabolic rate is known to increase in hyperthyroidism and decrease in hypothyroidism. The aim of this work was to investigate how changes in metabolism induced by THs could affect the activities of acetylcholinest...
Article
Full-text available
To investigate PON 1/Aryl activities in basketball players with or without alpha-T supplementation pre- and post-training. Vitamin E (alpha-tocopherol, alpha-T) reduces lipid peroxidation. Paraoxonase 1/arylesterase (PON 1/Aryl) activities are closely related to oxidation and atherogenesis. Blood was obtained from 10 players pre- (group A), post-ex...
Article
The aim of this study was to investigate whether the activities of erythrocyte membrane acetylcholinesterase (AChE), (Na (+),K (+))-ATPase and Mg (2+)-ATPase are modulated by a basketball training. Blood was obtained from 10 basketball players pre- and postexercise. Total antioxidant status (TAS), lactate and pyruvate concentrations were determined...
Article
Studies have implicated aspartame (ASP) ingestion in neurological problems. The aim of this study was to evaluate hippocampal Na(+),K(+)-ATPase and Mg(2+)-ATPase activities after incubation with ASP or each of ASP metabolites, phenylalanine (Phe), methanol (MeOH) and aspartic acid (asp) separately. Suckling rat hippocampal homogenates or pure Na(+)...
Article
Full-text available
To investigate the effect of alpha-Tocopherol (alpha-T) supplementation on S100B elevated serum levels in basketball players' training. Blood was obtained from 10 basketball players pre-exercise (group A), post-exercise (group B) and after 30 days on alpha-T (200 mg/24 h orally) supplementation pre- (group C) and post-training (group D). Blood samp...
Article
To compare serum paraoxonase/arylesterase (PON-aryl) activities in phenylketonuric (PKU) patients with high and low phenylalanine (Phe) blood concentration. Seventeen poorly controlled PKU children (off diet) underwent clinical and laboratory examinations before and after 30 days adhering to their special diet (on diet), whereas controls (N=24) wer...
Article
Unlabelled: Thyroid hormones (THs) are recognized as key metabolic hormones, and the metabolic rate increases in hyperthyroidism, while it decreases in hypothyroidism. The aim of this work was to investigate how changes in metabolism induced by THs could affect the activities of acetylcholinesterase (AChE), (Na(+), K(+))- and Mg(2+)-ATPase in the...
Article
Vitamin E (alpha-tocopherol, alpha-Te) and carnitine reduce lipid peroxidation. THE AIM WAS TO: To investigate the erythrocyte membrane acetylcholinesterase (AChE), Na+, K+-ATPase and Mg2+-ATPase activities in basketball players with or without alpha-Te supplementation, before and after training. In vitro, we aimed to find out any additional effect...
Article
L-Cysteine (L-Cys) is implicated in the reduction of free radical production. The aim of this study was to investigate whether L-Cys supplementation prevents modulation of the activities of erythrocyte membrane acetylcholinesterase (AChE), Na(+),K(+)-ATPase and Mg(2+)-ATPase induced by free radicals in basketball players during training. Blood was...
Article
Choline plays an important role in brain development. Choline-deficient diet (CDD) is known to produce (among other effects) a decrease in acetylcholine in rat brains. The aim of our study was to investigate how CDD administration during gestation and lactation could affect total antioxidant status (TAS) and activities of acetylcholinesterase (AChE...
Article
Background: Classical galactosaemia is caused by a deficiency of galactose-1-phosphate uridyl transferase, resulting in high galactose (Gal), galactose-1-phosphate (Gal-1-P) and galactitol blood levels. Galactose/lactose restriction intake is the only treatment. 8-hydroxy-2-desoxyguanosine (8-OHdG) is a marker of oxidized DNA damage. Aim: Since gal...
Article
The aim of this work was to investigate the role of homocysteine (Hey), L-alanine (Ala) and L-phenylalanine (Phe) in the effect of chronic dietary choline deprivation (CCD) on the activities of acetylcholinesterase (AChE) and (Na+,K+)-ATPase in the rat brain. Male and female Wistar rats were continuously kept off choline during their gestational pe...
Article
The aim of this work was to investigate how the metabolic reactions could affect the activities of acetylcholinesterase (AChE), (Na+,K +)-ATPase and Mg2+-ATPase in the brain regions (frontal cortex, hippocampus, hypothalamus and cerebellum) of hyperand hypothyroid adult male rats. Hyperthyroidism was induced in rats by subcutaneous administration o...
Article
Full-text available
Aim: To investigate PON 1/Aryl activities in basketball players with or without alpha-T supplementation pre- and post-training. Vitamin E (alphatocopherol, alpha-T) reduces lipid peroxidation. Paraoxonase 1/arylesterase (PON 1/Aryl) activities are closely related to oxidation and atherogenesis. Subject-Methods: Blood was obtained from 10 players pr...