Biomedical subjects

Elzbieta Skrzydlewska

Publications and source records attributed to Elzbieta Skrzydlewska.

At least 19 recordsLinked to original sources

PubMed2006

Parameters characterizing acid-base equilibria between cell membrane and solution and their application to monitoring the effect of various factors on the membrane.

The cell membrane is an extremely complicated object. It participates in a large number of equilibria. For this reason, it is impossible to determine the parameters of all of them. It is the purpose of this work to define a limited number of averaged parameters in order to describe the equilibria between cell membrane components and environmental components. These parameters are the total acidic functional group concentration as well as the basic group concentration and their association constants with hydrogen or hydroxyl ions. The parameters were determined using the pH dependence of the electric surface charge density. The usefulness of these parameters was checked by studying the effect of green tea on liver cells in ethanol poisoning. Ethanol provokes an increase in concentration of functional groups, positively and negatively charged, as well as an increase in the basic groups association constant and a decrease in acidic groups association constant. Administering green tea partly compensates the changes provoked by ethanol poisoning. The parameters proposed in this work, C(TA), C(TB), K(AH) and K(BOH), are suited for monitoring the changes caused by various factors.

Acid-Base Equilibrium↗

PubMed2006

Fasciola hepatica: effects on the antioxidative properties and lipid peroxidation of rat serum.

Fasciola hepatica infection is accompanied by increased formation of reactive oxygen species. The aim of this study was to analyze antioxidative properties of rat serum in the course of fasciolosis. Wistar rats were infected per os with 30 metacercariae of F. hepatica. Activities of antioxidant enzymes and concentrations of non-enzymatic antioxidants in serum were determined at 4, 7, and 10 weeks post-infection (wpi). Activity of superoxide dismutase (Cu, Zn-SOD) significantly decreased (by 35% during the migratory phase, by 40 and 23% at 7 and 10 wpi, respectively), while glutathione reductase activity significantly increased (by 62, 65, and 41%, at 4, 7, and 10 wpi, respectively). No significant changes were found in the activity of glutathione peroxidase. Significant decreases in concentrations of reduced glutathione, vitamins C, E, and A were observed, particularly during the migratory phase of fasciolosis (at 4 wpi). These changes were accompanied by enhancement of lipid peroxidation processes as evidenced by increased levels of malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE). Concentrations of MDA and 4-HNE at 4 wpi increased by 38% and by 59%. MDA increased by 51% at 7 wpi and by 79% at 10 wpi, while 4-HNE increased by 87 and 118%, respectively. The results indicate that fasciolosis is associated with enhanced oxidative reactions and reduced antioxidant defense capability of rat serum.

Aldehydes↗

PubMed2006

Protective effect of black tea against ethanol-induced oxidative modifications of liver proteins and lipids.

OBJECTIVE: Black tea has been recently ascertained as a source of water-soluble antioxidants that may enhance cellular antioxidant abilities. The present study was designed to investigate the efficacy of the preventive effect of black tea on oxidative modifications of liver lipids and proteins of 2-month-old rats intoxicated chronically (28 days) with ethanol. METHOD: Lipid peroxidation was estimated by measurement of lipid hydroperoxides, malondialdehyde, and 4-hydroxynonenal by high-performance liquid chromatography (HPLC) and by spectrophotometric determination of conjugated dienes. The markers of protein oxidative modification products-bistyrosine and tryptophan-were quantified by spectrofluorimetry, whereas levels of amino, sulfhydryl, and carbonyl groups were estimated spectrophotometrically. RESULTS: Ethanol intoxication caused changes in liver antioxidant abilities that led to the generation of oxidative stress and, consequently, to the significant increase in products of lipid and protein oxidative modification. Enhanced lipid peroxidation was confirmed by assessment of the concentration of lipid peroxidation products measured at all examined levels. Protein modifications were evidenced by increase in levels of bistyrosine and carbonyl groups and by decrease in concentration of tryptophan and levels of sulfhydryl and amino groups. The metabolic consequences of oxidative modifications of lipids and proteins were reduced by cathepsin B activity and translocation of this lysosomal protease into cytosol as well as markers of liver damage-alanine aminotransferase (ALT) and aspartate aminotransferase (AST)-into the blood serum. Administration of black tea to ethanol-intoxicated rats partially protected antioxidant parameters and, remarkably, prevented the significant increase in concentrations of all measured lipid peroxidation products. Moreover, the levels of markers of the protein-modification process were similar to those of the control group. Protection of biological membranes by black tea prevents changes in the permeability of these membranes and translocation of the examined enzymes. CONCLUSIONS: Our findings indicate that black tea protects proteins and lipids against oxidative modification induced by chronic ethanol intoxication, which preserves changes in redox and proteolytic homeostasis.

Alanine Transaminase↗

PubMed2006

[Assessment of antioxidative defense parameters in serum and age of patients showing antibodies anti-Borrelia burgdorferi presence--non-symptomatic carriers].

To evaluate in serum antioxidative deffence parameters--SOD EC.1.15.1.1 (superoxide dismutase), GSH-Px EC.1.15.1.1 (glutathine peroxidase), -SH (sulphhydryl groups) among patients previously diagnosed with borreliosis presently showing antibodies against Borrelia burgdorferi presence. The antioxidative deffence parameters were evaluated in 117 sera of patients with previously diagnosed borreliosis aged x = 43,07. Control group consisted of 39 persons aged x = 40,97 with no detectable anti-Borrelia burgdorferi antibodies in serum. Serologic diagnosis was performed with use of ELISA kit--Borrelia rekombinat IgM, IgG (Biomedica, Austria). Serum activity of antioxidative deffence parameters-- SOD EC.1.15.1.1 (superoxide dismutase), GSH-Px EC.1.15.1.1 (glutathine peroxidase), -SH (sulphhydryl groups) were detected in all patients from both groups. Obtained results were statistically analysed. There was showed no significant difference in serum activity of SOD and GSH-Px in group of former borreliosis patients and control group. Also serum -SH concentration did not differ significantly between both examined groups of patients. No correlation between SOD and GSH-Px serum activity as well as -SH concentration was detected.

Adolescent↗

PubMed2006

[The present-day look at lipid peroxidation].

Lipid peroxidation occurs in physiological conditions and it consists in oxidation of polyunsaturated fatty acids, which are basic biological membrane components. There are two pathway of lipid peroxidation: nonenzymatic and enzymatic. Both of the processes result in generation of various reactive products. Nonenzymatic lipid peroxidation consists in free radical oxidation of polyunsaturated fatty acids while in enzymatic lipid peroxidation the generation of lipid hydroxyperoxides is achieved by insertion of an oxygen molecule at the active centre of lipoxygenase. In this manuscript mechanisms of two processes are described in details. We concentrate on final products of oxidation fatty acids: isoprostanes and neuroprostanes which are regarded as the most important biomarkers of lipid peroxidation as well as on the role of enzymes participating in enzymatic lipid peroxidation process. Moreover we discuss catalytic activity of glutathione peroxidases and transferases--enzymes preventing results of oxidation polyunsaturated fatty acids.

Aldehydes↗

PubMed2005

Protective effect of green tea on erythrocyte membrane of different age rats intoxicated with ethanol.

It is known that aging is characterized by changes in cell metabolism resulting in modification of the structure and function of cell membrane components which is mainly the consequence of reactive oxygen species action. These disturbances are also enhanced by different xenobiotics, e.g. ethanol. Therefore, the aim of this paper is to examine green tea influence on total antioxidant status (TAS) and on composition and electric charge of erythrocyte membrane phospholipids in ethanol intoxicated rats of various ages. Antioxidant abilities of erythrocytes were estimated by measuring TAS. Qualitative and quantitative composition of phospholipids in the membrane was determined by HPLC, while the extent of erythrocytes lipid peroxidation was estimated by HPLC measurement of malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) levels. Electrophoresis was used to determine the surface charge density of the rat erythrocyte membrane. It was shown that the process of aging was accompanied by a decrease in TAS and in the total amount of phospholipids as well as by enhancement of lipid peroxidation and increase in surface charge density of erythrocyte membrane. Ethanol administration caused, in term, decrease in TAS and increase in the level of all phospholipids and lipid peroxidation products. Ethanol as well significantly enhanced changes in surface charge density of erythrocyte membrane. The ingestion of green tea partially prevented decrease in erythrocyte antioxidant abilities observed during aging and ethanol intoxication. Moreover, long-term drinking of green tea protects the structure of the erythrocytes membrane disturbed during aging process and/or chronic ethanol intoxication.

Aging↗

PubMed2005

Evaluation of serum cathepsin B and D in relation to clinicopathological staging of colorectal cancer.

AIM: Proteolytic degradation of the extracellular matrix facilitates cancer invasion and promotes metastasis. The study aims at evaluation of preoperative and postoperative serum cathepsins B and D levels in correlation with selected anatomoclinical features of colorectal cancer. METHODS: Blood samples were collected from 63 colorectal cancer patients before curative operation of the tumor 10 d later. Blood that was obtained from 20 healthy volunteers, served as a control. The activity of cathepsin B was measured with Bz-DL-arginine-pNA as a substrate at pH 6.0, while cathepsin D activity was determined with urea-denatured hemoglobin (pH 4.0). RESULTS: The preoperative and postoperative activities of cathepsin B were significantly (P<0.00001) lower in serum of colorectal cancer patients than in control group. However, postoperative values of this protease were significantly increased in comparison with preoperative ones (P = 0.031). Activity of cathepsin D appeared to be significantly higher in colorectal cancer sera (P<0.00001) compared with controls. No statistically significant differences between preoperative and postoperative activity of cathepsin D were noted (P = 0.09). We revealed a strong linkage of cathepsins' levels with lymph node status and pT stage of colorectal cancer. CONCLUSION: Blood serum activities of cathepsin B and D depend on the time of sampling, tumor size and lymph node involvement. Significantly, increased activity of cathepsin D could indicate a malignant condition of the large intestine. In our work, the serum postoperative decrease of cathepsin B activity appears as an obvious concomitant of local lymph node metastasis-the well-known clinicopathological feature of poor prognosis.

Aged↗

PubMed2005

Connexin 26 correlates with Bcl-xL and Bax proteins expression in colorectal cancer.

AIM: To evaluate of Cx26 in correlation with Bcl-xL and Bax proteins in colorectal cancer. METHODS: Immunohistochemical staining using specific antibodies was performed to evaluate the protein expression of Cx26, Bax and Bcl-xL in 152 colorectal cancer samples and the correlations among studied proteins as well as the relationships between the expression of Cx26, Bax, Bcl-xL and clinicopathological features were analyzed. RESULTS: Both normal epithelial cells and carcinoma cells expressed Cx26, Bax and Bcl-xL, but Cx26 in cancer cells showed aberrant, mainly cytoplasmic staining. Expression of Cx26, Bax and Bcl-xL was observed in 55.9%, 55.5% and 72.4% of evaluated colorectal cancers respectively. We found the positive correlation between Cx26 and Bax expression (r = 0.561, P<0.0001), Cx26 and Bcl-xL (r = 0.409, P<0.0001) as well as between Bax and Bcl-xL (r = 0.486, P<0.0001). Association of Cx26, Bax and Bcl-xL expression with histological G2 grade of tumors was noted (P<0.005, P<0.001 and P<0.002 respectively). CONCLUSION: Cytoplasmic presence of Cx26 and its association with apoptotic markers could indicate a distinct role from physiological functions of Cx26 in cancer cells and it could suggest that connexins might be a target point for modulations of apoptosis with therapeutic implications.

Adult↗

PubMed2005

Proteolytic-antiproteolytic balance and its regulation in carcinogenesis.

Cancer development is essentially a tissue remodeling process in which normal tissue is substituted with cancer tissue. A crucial role in this process is attributed to proteolytic degradation of the extracellular matrix (ECM). Degradation of ECM is initiated by proteases, secreted by different cell types, participating in tumor cell invasion and increased expression or activity of every known class of proteases (metallo-, serine-, aspartyl-, and cysteine) has been linked to malignancy and invasion of tumor cells. Proteolytic enzymes can act directly by degrading ECM or indirectly by activating other proteases, which then degrade the ECM. They act in a determined order, resulting from the order of their activation. When proteases exert their action on other proteases, the end result is a cascade leading to proteolysis. Presumable order of events in this complicated cascade is that aspartyl protease (cathepsin D) activates cysteine proteases (e.g. cathepsin B) that can activate pro-uPA. Then active uPA can convert plasminogen into plasmin. Cathepsin B as well as plasmin are capable of degrading several components of tumor stroma and may activate zymogens of matrix metalloproteinases, the main family of ECM degrading proteases. The activities of these proteases are regulated by a complex array of activators, inhibitors and cellular receptors. In physiological conditions the balance exists between proteases and their inhibitors. Proteolytic-antiproteolytic balance may be of major significance in the cancer development. One of the reasons for such a situation is enhanced generation of free radicals observed in many pathological states. Free radicals react with main cellular components like proteins and lipids and in this way modify proteolytic-antiproteolytic balance and enable penetration damaging cellular membrane. All these lead to enhancement of proteolysis and destruction of ECM proteins and in consequence to invasion and metastasis.

Extracellular Matrix↗

PubMed2005

Lipid peroxidation and antioxidant status in colorectal cancer.

AIM: Reactive oxygen species (ROS) can induce carcinogenesis via DNA injury. Both enzymatic and non-enzymatic parameters participate in cell protection against harmful influence of oxidative stress. The aim of the present study was to assess the levels of final lipid peroxidation products like malondialdehyde (MDA) and 4-hydroxy-2-nonenal (4-HNE) in primary colorectal cancer. Moreover, we analysed the activity of main antioxidative enzymes, superoxide dismutase (Cu, Zn-SOD), catalase (CAT), glutathione peroxidase (GSH-Px) and glutathione reductase (GSSRG-R) and the level of non-enzymatic antioxidants (glutathione, vitamins C and E). METHODS: Investigations were conducted in 81 primary colorectal cancers. As a control, the same amount of sample was collected from macroscopically unchanged colon regions of the most distant location to the cancer. Homogenisation of specimens provided 10% homogenates for our evaluations. Activity of antioxidant enzymes and level of glutathione were determined by spectrophotometry. HPLC revealed levels of vitamins C and E and served as a method to detect terminal products of lipid peroxidation in colorectal cancer. RESULTS: Our studies demonstrated a statistically significant increase in the level of lipid peroxidation products (MDA-Adc.muc.-2.65+/-0.48 nmol/g, Adc.G3-2.15+/-0.44 nmol/g, clinical IV stage 4.04+/-0.47 nmol/g, P<0.001 and 4-HNE-Adc.muc. -0.44+/-0.07 nmol/g, Adc.G3-0.44+/-0.10 nmol/g, clinical IV stage 0.52+/-0.11 nmol/g, P<0.001) as well as increase of Cu,Zn-SOD (Adc.muc.-363+/-72 U/g, Adc.G3-318+/-48 U/g, clinical IV stage 421+/-58 U/g, P<0.001), GSH-Px (Adc.muc. -2143+/-623 U/g, Adc.G3-2005+/-591 U/g, clinical IV stage 2467+/-368 U/g, P<0.001) and GSSG-R (Adc.muc.-880+/-194 U/g, Adc.G3-795+/-228 U/g, clinical IV stage 951+/-243 U/g, P<0.001) in primary tumour comparison with normal colon (MDA-1.39+/-0.15 nmol/g, HNE-0.29+/-0.03 nmol/g, Cu, Zn-SOD-117+/-25 U/g, GSH-Px-1723+/-189 U/g, GSSG-R-625+/-112 U/g) especially in mucinous and G3-grade adenocarcinomas as well as clinical IV stage of colorectal cancer. We also observed a decrease of CAT activity (Adc.muc. -40+/-14 U/g, clinical IV stage 33+/-18 U/g vs 84+/-17 U/g, P<0.001) as well as a decreased level of reduced glutathione (clinical IV stage 150+/-48 nmol/g vs 167+/-15 nmol/g, P<0.05) and vitamins C and E (vit. C-clinical IV stage 325+/-92 nmol/g vs 513+/-64 nmol/g, P<0.001; vit. E-clinical IV stage 13.3+/-10.3 nmol/g vs 37.5+/-5.2 nmol/g). CONCLUSION: Colorectal carcinogenesis is associated with serious oxidative stress and confirms that gradual advancement of oxidative-antioxidative disorders is followed by progression of colorectal cancer.

Antioxidants↗

PubMed2005

Green tea supplementation in rats of different ages mitigates ethanol-induced changes in brain antioxidant abilities.

Oxidative stress induced by chronic ethanol consumption, particularly in aging subjects, has been implicated in the pathophysiology of many neurodegenerative diseases. Antioxidants with polyphenol structures, such as those contained in green tea, given alone for 5 weeks in liquid Lieber de Carli diet followed by administration with ethanol for 4 weeks with ethanol have been investigated as potential therapeutic antioxidant agents in the brain in rats of three ages (2, 12, and 24 months). Ethanol consumption caused age-dependent decreases in brain superoxide dismutase, glutathione peroxidase, glutathione reductase, and catalase activities. In addition, ethanol consumption caused age-dependent decreases in the levels of GSH, selenium, vitamins, E, A and C, and beta-carotene and increases in the levels of oxidized glutathione (GSSG). Changes in the brain's antioxidative ability were accompanied by enhanced oxidative modification of lipids (increases in lipid hydroperoxides, malondialdehyde, and 4-hydroxynonenal levels) and proteins (increases in carbonyl groups and bistyrosine). Reduced risk of oxidative stress and protection of the central nervous system, particularly in young and adult rats, after green tea supplementation were observed. Green tea partially prevented changes in antioxidant enzymatic as well as nonenzymatic parameters induced by ethanol and enhanced by aging. Administration of green tea significantly protects lipids and proteins against oxidative modifications in the brain tissue of young and adult rats. The beneficial effect of green tea can result from the inhibition of free radical chain reactions generated during ethanol-induced oxidative stress and/or from green tea-induced increases in antioxidative abilities made possible by increases in the activity/concentration of endogenous antioxidants.

Aging↗

PubMed2005

Preventive action of green tea from changes in the liver antioxidant abilities of different aged rats intoxicated with ethanol.

OBJECTIVE: The present study investigated the influence of green tea as a source of water-soluble antioxidants on the liver antioxidant potential of different aged rats chronically intoxicated with ethanol. METHODS: Rats (2, 12, and 24 mo old) were fed for 5 wk on a control or an ethanol Lieber-DeCarli diet with and without green tea (7 g/L). The activity and level of enzymatic and non-enzymatic antioxidants and the level of markers of protein and lipid oxidation in the liver of rats were examined. RESULTS: The activities of superoxide dismutase and catalase and levels of vitamins C, E, A, and beta-carotene were significantly decreased, whereas activities of glutathione peroxidase and glutathione reductase and the level of reduced glutathione significantly increased during aging. The ethanol diet caused a significant decrease in activity of antioxidant enzymes and in the level of non-enzymatic antioxidants tested. Administration of green tea to ethanol-treated rats of different ages partly normalized the activity of enzymes and the level of non-enzymatic antioxidants. Changes in antioxidant ability observed during aging were accompanied by increased levels of markers of lipid and protein modifications that also were intensified by ethanol. Green tea caused a decrease in lipid and protein oxidation in aged and ethanol-treated rats. The protective effect of green tea was confirmed by the significantly lower activity of biomarkers of liver damage (alanine and aspartate aminotransferases) in the serum of rats that received green tea with ethanol compared with rats from the control ethanol group. CONCLUSIONS: The use of green tea appears to be beneficial to rat liver by decreasing oxidative stress caused by ethanol and/or aging.

Age Factors↗

PubMed2005

Cancer procoagulant in patients with adenocarcinomas.

Cancer procoagulant (CP) is a cysteine proteinase that may be produced by malignant and foetal tissue. The possible role of CP in the pathogenesis of cancer-related thrombosis has been suggested recently. The purpose of the study was to evaluate coagulation prothrombotic markers and their relation to CP concentration in the blood of patients with gastrointestinal adenocarcinomas (GIAC). The study group consisted of 45 patients with confirmed diagnosis of adenocarcinoma (stomach, 18 patients; colon, 27 patients) and without evident metastatic disease. In 24 patients further observation showed metastases. The control group for CP was composed of 10 healthy subjects. Blood samples were drawn on the admission day, before any treatment. Among 45 patients with GIAC, deep venous thrombosis was observed in two (4.4%). In all patients the CP activity in the serum was found, and the mean CP activity shortened the coagulation time almost three times compared with the healthy control group. Also, the mean thrombin-antithrombin complex concentration was above the normal range. A significant elevation of the mean prothrombin fragment 1+2 plasma content in this group of patients was noticed. Despite these observations, CP remained within the normal range and did not correlate with thrombin-antithrombin complex or prothrombin fragment 1+2 plasma concentrations. A positive correlation was observed between serum CP and fibrinogen concentration, and a negative correlation between CP and free protein S plasma content (P = 0.04 and P = 0.025, respectively). A negative correlation between activated protein C resistance ratio and protein C activity in the plasma was confirmed. Protein C activity in the plasma showed a correlation with free protein S plasma content. Analysis of factors influencing the activated partial thromboplastin time revealed the presence of antiphospholipid antibodies in seven persons from the study group (in three cases of IgG and in four cases of IgM class). Our data suggest that CP is a minor risk factor for deep venous thrombosis in GIAC patients. To confirm this, however, the number of patients and controls should be larger. After 3 years of observation, the follow-up in 10 living GIAC patients showed nobody with thromboembolic disease.

Adenocarcinoma↗

PubMed2005

[Coenzyme Q10: its biosynthesis and biological significance in animal organisms and in humans].

Coenzyme Q10 (ubiquinone) is a naturally occurring compound widely distributed in animal organisms and in humans. The primary compounds involved in the biosynthesis of ubiquinone are 4-hydroxybenzoate and the polyprenyl chain. An essential role of coenzyme Q10 is as an electron carrier in the mitochondrial respiratory chain. Moreover, coenzyme Q10 is one of the most important lipophilic antioxidants, preventing the generation of free radicals as well as oxidative modifications of proteins, lipids, and DNA, it and can also regenerate the other powerful lipophilic antioxidant, alpha-tocopherol. Antioxidant action is a property of the reduced form of coenzyme Q10, ubiquinol (CoQ10H2), and the ubisemiquinone radical (CoQ10H*). Paradoxically, independently of the known antioxidant properties of coenzyme Q10, the ubisemiquinone radical anion (CoQ10-) possesses prooxidative properties. Decreased levels of coenzyme Q10 in humans are observed in many pathologies (e.g. cardiac disorders, neurodegenerative diseases, AIDS, cancer) associated with intensive generation of free radicals and their action on cells and tissues. In these cases, treatment involves pharmaceutical supplementation or increased consumption of coenzyme Q10 with meals as well as treatment with suitable chemical compounds (i.e. folic acid or B-group vitamins) which significantly increase ubiquinone biosynthesis in the organism. Estimation of coenzyme Q10 deficiency and efficiency of its supplementation requires a determination of ubiquinone levels in the organism. Therefore, highly selective and sensitive methods must be applied, such as HPLC with UV or coulometric detection.

Animals↗

PubMed2005

[Vitamin A, E and C serum concentration in patients with Borrelia burgdorferi antibodies--non-symptomatic carriers].

To estimate vitamin A, E and C serum concentrations among forestry workers showing antibodies against Borrelia burgdorferi presence. Vitamins A, E and C concentrations were evaluated in 117 sera of forestry workers. 78 persons aged 18-63 (x=43.07) showed antibodies against Borrelia burgdorferi presence. In this group 13 persons showed presence of IgM, 42 persons with IgG and 23 with IgM and IgG. Control group consisted of 39 persons aged 18-56 years (x=40,97), with no detectable anti-Borrelia burgdorferi antibodies in serum. Serologic diagnosis was performed with use of ELISA kit - Borrelia recombinant IgM, IgG (Biomedica, Austria). Vitamins A and E serum concentrations were detected by RP-HPLC method with spectrophotometric detection (De Leenheet and co.). Vitamin C was detected by RP-HPLS method with spectrophotometric method (Ivanovic and co). Obtains results were statistically analysed. Significantly lower of vitamin A and E serum concentration of persons with anti-borrelia antibodies presence. The lowest concentration was observed in group showing presence of IgM and IgG. No significant difference in vitamin C serum concentration in examined groups was observed. These results may suggest that low serum concentrations of vitamin A and E may have influence on Borrelia burgdorferi infection development.

Adolescent↗

PubMed2005

[The action of oxidative stress induced by ethanol on the central nervous system (CNS)].

The brain is an organ which metabolically consumes about 20% of the total oxygen received by the organism. This causes the generation of free radicals, especially in the presence of some xenobiotics, such as ethanol. In order to prevent free radical-induced cellular damage, the organism developed a defense mechanism, the antioxidative system. The content of both exogenous and endogenous antioxidants in the central nervous system (CNS) is very small in comparison with that of other tissues, which in relation to the high level of polyunsaturated fatty acids (PUFAs) makes the CNS exceptionally susceptible to free-radical damage. The antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione reductase (GSSG-R) are present in the CNS i.e. in the cortex, cerebellum, hypothalamus, striatum, and spinal cord, where they are responsible for the brain's basic functions, both physical and cognitive. Moreover, the highest activity of these enzymes is observed in neurons and/or glial cells. The activity of antioxidant enzymes is significantly changed in the CNS of animals chronically intoxicated with ethanol. The decrease in these activity may indicate at oxidative modification of the enzymatic proteins caused by free radicals which are generated during ethanol and acetaldehyde metabolism. It may also be caused by the decrease in the synthesis rate of these enzymes. However, the increase in the activity of antioxidant enzymes may often be explained as an adaptive reaction to an excess production of free radicals. The catalase is an exception in this respect because the decrease in its activity is related to the enhancement of protein synthesis. Ethanol intoxication also caused a decrease in GSH concentration, especially in the cerebellum, striatum, and cortex. This may be explained by the increase in the concentration of acetaldehyde, which is removed from cells with the use of this antioxidant. The antioxidative abilities of the CNS also depend on exogenous antioxidants which are provided to the organism during food intake. The most important exogenous antioxidant in the CNS is vitamin E. The content of vitamin E as well as that of vitamin C in the CNS is decreased, whereas the content of vitamin A is increased after ethanol administration. The high vitamin A level may cause damage of the central nervous system, especially in young rats exposed to ethanol in the prenatal period.

Alcoholism↗

PubMed2004

Green tea protection against age-dependent ethanol-induced oxidative stress.

Ethanol intoxication leads to oxidative stress, which may be additionally enhanced by aging. The aim of this study was to investigate the influence of green tea as a source of water-soluble antioxidants on the ability to prevent oxidative stress in aged rats sub-chronically intoxicated with ethanol. Two-, 12-, and 24-mo-old male Wistar rats were divided into 4 experimental groups: (1) control, (2) green tea, (3) ethanol, and (4) ethanol and green tea. Ethanol intoxication produced age-dependent decrease in the activity of serum superoxide dismutase, glutathione peroxidase, and reductase and in levels of glutathione (GSH), vitamins C, E, and A, and beta-carotene. Changes in the serum antioxidative ability were accompanied by enhanced oxidative modification of lipid (increase in lipid hydroperoxides, malondiadehyde, and 4-hydroxynonenal levels) and protein (rise in carbonyl group levels). Green tea partially protected against changes in antioxidant enzymatic as well as nonenzymatic parameters produced by ethanol and enhanced by aging. Administration of green tea significantly protects cellular components such as lipids and proteins against oxidative modification. Results indicate that green tea effectively protects blood serum against oxidative stress produced by ethanol as well as aging.

Aging↗

PubMed2004

[Antioxidative abilities during aging].

Biological aging is associated with increased cellular levels of reactive oxygen species (ROS) as well as the formation and accumulation of oxidized biomolecules. During evolution, organisms developed a highly-efficient and adaptive antioxidant defense system. Antioxidants can generally be divided into two categories: enzymatic and non-enzymatic. During the aging process the activity of antioxidant enzymes, e.g. SOD, CAT, GSH-Px, and GSSG-R, depends on factors such as race, gender, tissue and subcellular localization of enzymes. The age-dependent decrease in antioxidant enzyme activity may be attributed to oxidative modifications of enzymes. During the aging process, ROS may also lead to the induction of some enzyme activity which is explained as an adaptive phenomenon. The decrease in GSH concentration with age can be explained by decreased GSH synthesis and/or increased GSH consumption in the removal of peroxides and xenobiotics. In plasma albumin, ferritin, transferrin, and caeruloplasmin exert protective action. Plasma proteins can inhibit ROS generation and lipid peroxidation by chelating free transition metals. Plasma protein concentrations changes with age. The major exogenous antioxidants, mostly derived from the diet, are vitamin E, C, A, and beta-carotene. During the aging process the level of vitamins may decrease or increase, depending on such factors as diet, and diseases.

Aging↗