Kleopatra H. Schulpis

Protective effect of L-phenylalanine on rat brain acetylcholinesterase inhibition induced by free radicals.

OBJECTIVE To investigate whether the preincubation of brain homogenates with L-phenylalanine (Phe) could reverse the free radical effects on brain acetylcholinesterase (AChE) activity, since it has been reported that Phe binds hydroxyl radicals ((*)OH). DESIGN AND METHODS Two well established systems were used for production of free radicals: (a) FeSO(4) (84 microM) plus ascorbic acid (400 microM), and (b) FeSO(4), ascorbic acid and H(2)O(2) (1 mM) at 37 degrees C in homogenates of adult rat whole brain. Changes in brain AChE activity were studied in the presence of each system separately. RESULTS AChE was inhibited (18-28%) by both systems of free radicals. This inhibition was reversed when the brain homogenate was preincubated with Phe 1.8 mM. CONCLUSIONS In accordance with our previous reports, Phe could protect against the direct action of (*)OH radicals on brain AChE and in this way it might be useful in the prevention of certain cholinergic neural dysfunctions.

Effect of diet on plasma total antioxidant status in phenylketonuric patients

Background: Phenylketonuria (PKU), an inborn error of phenylalanine (Phe) metabolism, is treated with a low Phe lifelong diet, which is a vegetarian and contains many antioxidants.Aim: The aim of this study was to evaluate the effect of diet on plasma total antioxidant status in our PKU patients.Methods, Results: Twenty-two PKU patients on strict diet (group A), 24 PKU patients who did not accurately follow their dietary control (group B) and 40 healthy children (controls) of comparable age took part in this study. Nutrients, as well as blood levels of lipids, vitamin C, β-carotene and α-tocopherol were evaluated in all groups. Vitamin C intake and its blood levels did not differ between the groups. However, the intake of β-carotene, α-tocopherol (2211±116, 14±1.0 mg/24 h) and their blood levels (0.7±0.09, 34±0.9 µmol/l) in group A were statistically significantly higher (P<0.001) as compared with those of group B (1352±118, 10±1.0 mg/24 h and 0.49±0.08, 22±0.6 µmol/l) and controls (1290±120, 9.0±0.9 mg/24 h and 0.40±0.09, 24±1.6 µmol/l). Lipid intakes and their blood levels were lower in patients on the strict diet. Plasma total antioxidant status was higher in the same group of patients (group A). Additionally, positive correlations were found between the antioxidant vitamin blood levels and the plasma total antioxidant status in the groups, especially in the group A. PKU patients of group A showed significantly higher antioxidant status (1.6±0.2 mmol/l) as compared with those of group B (1.0±0.19 mmol/l; P<0.001) and controls (1.01±0.2 mmol/l).Conclusions: The high plasma antioxidant status in patients with PKU, especially in those with a good compliance with their diet, is possibly due to the amounts of antioxidants which are present in their special low Phe vegetarian diet.

Protective effect of L-cysteine and glutathione on rat brain Na+,K+-ATPase inhibition induced by free radicals.

Abstract The aim of this study was to investigate whether the preincubation of brain homogenates with L-phenylalanine (Phe), L-cysteine (Cys) or reduced glutathione (G SH) could reverse the free radical effects on Na+,K+-ATPase activity. Two well established systems were used for the production of free radicals: 1) FeSO4 (84 μᴍ ) plus ascorbic acid (400 μᴍ ) and 2) FeSO4, ascorbic acid and H2O2 (1 mᴍ) for 10 min at 37 °C in homogenates of adult rat whole brain. Changes in brain Na+,K+-ATPase activity and total antioxidant status (TAS) were studied in the presence of each system separately, with or without Phe, Cys or GSH. TAS value reflects the amount of free radicals and the capacity of the antioxidant enzymes to limit the free radicals in the homogenate. Na+,K+-ATPase was inhibited by 35-50% and TAS value was decreased by 50-60% by both systems of free radical production. The enzymatic inhibition was completely reversed and TAS value increased by 150-180% when brain homogenates were preincubated with 0.83 mᴍ Cys or GSH. However, this Na+,K+-ATPase inhibition was not affected by 1.80 mᴍ Phe, which produced a 45-50% increase in TAS value. It is suggested that the antioxidant action of Cys and GSH may be due to the binding of free radicals to sulfhydryl groups of the molecule, so that free radicals cannot induce Na+,K+-ATPase inhibition. Moreover, Cys and GSH could regulate towards normal values the neural excitability and metabolic energy production, which may be disturbed by free radical action on Na+,K+-ATPase.

Structural and functional alterations in the hippocampus due to hypothyroidism

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 of its direct and indirect interactions with the THs could provide crucial information on the neurobiological basis of the (frequently-faced in clinical practice) hypothyroidism-induced mental retardation and neurobehavioral dysfunction. THs-deficiency during the fetal and/or the neonatal period produces deleterious effects for neural growth and development (such as reduced synaptic connectivity, delayed myelination, disturbed neuronal migration, deranged axonal projections, decreased synaptogenesis and alterations in neurotransmitters’ levels). On the other hand, the adult-onset thyroid dysfunction is usually associated with neurological and behavioural abnormalities. In both cases, genomic and proteomic changes seem to occur. The aim of this review is to provide an up-to-date synopsis of the available knowledge regarding the aforementioned alterations that take place in the hippocampus due to fetal-, neonatal- or adult-onset hypothyroidism.

Alpha-tocopherol supplementation prevents the exercise-induced reduction of serum paraoxonase 1/arylesterase activities in healthy individuals

Objective:To investigate PON 1/Aryl activities in basketball players with or without α-T supplementation pre- and post-training. Vitamin E (α-tocopherol, α-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 pre- (group A), post-exercise (group B) and after 1 month on α-T (200 mg per 24 h orally) supplementation pre- (group C) and post-exercise (group D). Lactate, pyruvate, muscle enzyme activities, creatine kinase, lactate dehydrogenase and total antioxidant status (TAS) were measured with commercial kits. Catecholamines and α-T were determined with high-performance liquid chromatography methods and PON 1/Aryl activities spectrophotometrically.Results:Lactate, pyruvate, muscle enzyme activities and catecholamines were increased (P<0.001) in all groups post-training. Alpha-T levels remained unaltered pre- vs post-exercise. TAS was decreased in all the groups post training. PON 1/Aryl activities were significantly decreased post-exercise (group B) (PON1: 65±12 U min−1 ml−1, Aryl: 58±14 KU min−1 ml−1) as compared to those pre-exercise (group A) (PON1: 142±16 U min−1 ml−1, Aryl: 114±12 KU min−1 ml−1, P<0.001). In contrast, the studied enzyme activities remained practically unaltered after α-T supplementation pre- vs post-training. Both enzyme activities positively correlated to TAS (r=0.60, P<0.001).Conclusions:Alpha-T supplementation may result in protection of the enzyme PON 1/Aryl activities from free radical production.

Maternal-neonatal 8-hydroxy-deoxyguanosine serum concentrations as an index of DNA oxidation in association with the mode of labour and delivery

Aim. To investigate the effect of the mode of labour and delivery on the total antioxidant status (TAS), and the biomarker of DNA oxidation, 8‐hydroxy‐deoxyguanosine (8‐OHdG) serum levels, in mothers and their newborns. Subjects and methods. Some 106 women with normal pregnancy and normal blood biochemical parameters were divided into 4 groups: Group A (n = 28) with normal labour and vaginal delivery (VG), Group B (n = 25) with scheduled cesarean section (CS), Group C (n = 26) with ‘emergency’ CS, and Group D (n = 27) with prolonged labour + VG. Blood was obtained from the mothers at the beginning of labour, and immediately after delivery (pre‐ and post‐delivery), as well as from the umbilical cord (CB). TAS, 8‐OHdG and creatine kinase (CK) were measured in the sera with appropriate methodology. Results. TAS levels were almost similar in all the groups pre‐delivery, and in CB irrespective of the mode of labour and delivery, and remarkably decreased in Groups C and D post‐delivery. 8‐OHdG levels in Group C (0.94±0.08 ng/ml) and Group D (0.98±0.08 ng/ml) were significantly higher than those in Group A (0.26±0.01 ng/ml, p<0.001) and Group B (0.28±0.07 ng/ml, p<0.001) post‐delivery. 8‐OHdG levels were low in CB, independent of the mode of labour. CK positively correlated with 8‐OHdG (r = 0.48, p<0.001), the latter negatively correlated with TAS (r = − 0.53, p<0.01). Conclusions. The lowest TAS and the highest 8‐OHdG levels were found in Groups C and D post‐delivery, probably due to the long‐term participation of the mothers’ skeletal and uterus muscles, whereas 8‐OHdG levels were low in CB irrespective of the mode of delivery, possibly as a consequence of the antioxidant action of the placenta and/or the low lipid levels in the serum of the umbilical cord.

Raised β-endorphin serum levels in children with atopic dermatitis and pruritus

Atopic dermatits (AD) is a pruritic cutaneous inflammatory condition. As pruritus and pain are very close symptoms, we determined the β-endorphin serum concentrations in 21 atopic children with pruritus (group A) and 20 children with healed AD without pruritus (group B). Twenty-five healthy school children were the control group. The β-endorphin serum concentrations (14.95 ± 2.75 pmol/l) in group A were statistically (P < 0.001) elevated in our patients compared to controls (8.85 ± 2.39 pmol/l) whereas these in group B were not elevated (9.4 ± 2.46 pmol/l). We suggest that the elevated β-endorphin concentrations in atopic patients with pruritus confirm the hypothesis that there is an increased activity of their opioid system and that an opioid antagonist might block itching which is their major clinical symptom.

Effects of mode of delivery on maternal–neonatal plasma antioxidant status and on protein S100B serum concentrations

Objective. To investigate the effect of the mode of labour and delivery on total antioxidant status (TAS) and on the protein S100B serum concentrations in mothers and their newborns. Material and methods. Sixty women with normal pregnancies were divided into three groups: Group A (n = 20) with normal labour and vaginal delivery (VG), group B (n = 18) with prolonged labour+VG and group C (n = 22) with scheduled caesarean section (CS). Blood was obtained at the beginning of the labour process and immediately after delivery (pre‐ and post‐delivery) as well as from the umbilical cord (CB). TAS and creatine kinase (CK) were measured using commercial kits. Serum S100B levels were evaluated with the electrochemiluminescence immunoassay “ECLIA” on the ROCHE ELECSYS 2010 immunoassay analyser. Results. Post‐delivery, TAS levels were significantly decreased in group A and especially in group B. S100B levels were increased in group B (0.0712±0.02 µg/L) as compared with those of group A (0.0567±0.03 µg/L, p<0.01) and group C (0.038±0.03 µg/L, p<0.01), the levels in group C remaining practically unaltered (pre‐ versus post‐delivery). In the newborns, S100B levels were almost 2‐fold higher in group B (0.67±0.18 µg/L) than those in group A (0.40±0.05 µg/L p<0.001) and group C (0.31±0.04 µg/L p<0.001). A negative correlation was found between TAS and S100B protein (r = −0.61, p<0.001), the latter positively correlated to CK (r = 0.48, p<0.01). Conclusions. The increased S100B serum levels in the mothers of group B, post‐delivery, may have been due to the long‐lasting, oxidative and/or psychogenic stress. The observed remarkably high levels of S100B in the group B newborns may have been due to compressive conditions on the foetus brain during this mode of delivery.

Homocysteine and other vascular risk factors in patients with phenylketonuria on a diet

The aim of this study was to investigate the known risk factors, such as lipids, homocysteine and endothelin, for the development of coronary artery disease (CAD) in phenylketonuria (PKU) patients, depending on their diet. The PKU patients (n= 74) were divided into two groups. Group A (n= 34; mean age 6.78 ± 1.5 y) adhered strictly to a diet and group B (n= 40; mean age 8.0 ± 3.2 y) did not comply with the diet. The control group comprised 50 healthy non‐PKU children. All groups were evaluated for blood levels of homocysteine and vitamin B6 by high‐performance liquid chromatography, vitamin B12 and folate in serum by a radioassay, lipids by a routine method, and lipoprotein(a) and endothelin‐1 with an immunoassay. Homocysteine levels (28.65 ± 3.3 μmol 1‐1) were increased in group A compared with group B (6.86 ± 1.6 μmol 1‐1) and the controls (6.9 ± 2.0 μmol 1‐1) (p > 0.001). Vitamin B6 (10.7 ± 10.9 nmol 1‐1), vitamin B12 (98.5 ± 22.3 pmol 1‐1), folate (2.35 ± 1.3 nmol 1‐1) and lipids were decreased in group A. The other vascular risk factors, which were not dependent on diet [lipoprotein(a) and endothelin‐1], did not differ among the three groups.

Serum copper and zinc concentrations in healthy children aged 3–14 years in greece

Zinc (Zn) and copper (Cu) are essential trace elements in people, being required for functional activity of several enzyme systems. In this study, we determined Cu and Zn concentrations in the serum of 105 healthy children randomly selected, aged 3–14 yr, residing in a region of Greece (Thrace), and we investigated their association with childrens gender, age, height, weight, and nutritional habits. The mean levels of Zn and Cu were 15.01±2.95 μmol/L and 26.18±5.47 μmol/L, respectively, with no significant difference between boys and girls. A significant positive correlation was found between age and Zn levels, and a negative one was found between age and Cu levels. Both Zn and Cu levels tended to increase with height, whereas Zn levels significantly decreased with increasing body mass indent (BMI). The consumption of meat, milk, and eggs were independent determinants for higher Zn levels, and the consumption of legumes and fruits were independent determinants for higher Cu levels. A significant negative correlation was found between Zn and Cu levels. In conclusion, our study, the first one evaluating the serum status of Cu and Zn in healthy Greek children, identified significant correlations of Zn and Cu levels with their age, height, BMI, and nutritional habits.