Erythrocyte Malondialdehyde Concentration Research Articles

Determination of blood heavy metal concentrations and oxidant-antioxidant capacities in Angora cats at different age and gender

This study was conducted to investigate heavy metal concentrations and oxidative status of plasma and erythrocytes in Angora cats at different ages and gender. Sixteen young (less than 1 year old) and 14 adult (1–6 years old) cats were also grouped according to gender as male (n = 17) and female (n = 13). The separated plasma samples from cat’s blood were analyzed for selected heavy metals and total oxidant and antioxidant capacities (TOC and TAC) and calculated for oxidative stress index (OSI). The erythrocyte hemolysates were also evaluated for malondialdehyde (MDA), and super oxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPX). Results of the study showed that most of the measured metals were not varied statistically according to age or gender. However, adult cats had significantly (P<0.01) higher Cu and lower Fe levels compared to young cats. Plasma levels of TOC, TAC and OSI, and erythrocyte MDA concentrations in young cats were significantly (P<0.05) higher than that of adults. While the SOD activity was decreased by the age, GPX activity was increased (P<0.05). However, the activity of CAT was changed by only gender, which was higher in males (P<0.01). In conclusion, metals, especially trace elements, are required for many kinds of physiological processes and the synthesis of antioxidant enzymes. Therefore, it can be suggested that the periodic measurement of metals and the addition of common antioxidant supplements to the diet of adult Angora cats will support weakening antioxidant mechanisms by age.

Daytime Evaluation of Oxidative Stress and Behavioural Parameters of Donkeys (Equus asinus) During The Hot-Dry and Cold-Dry (Harmattan) Season in a Tropical Savannah

ABSTRACT The aim of the study was to evaluate oxidative stress and behavioural responses of donkeys during the cold-dry and hot-dry seasons. Thirty donkeys divided into three groups of ten donkeys each according to their age served as experimental subjects. During each season, behavioural and blood parameters of the donkeys were evaluated three times with an interval of one week at 06:00 h, 12:00 h and 18:00 h (GMT+1). During the hot-dry season, the peak dry-bulb temperature (DBT) value of 36.00 ± 1.00°C was recorded at 12:00 h, indicating that the season induced heat stress. The time spent feeding demonstrated diurnal fluctuations in adult, yearling and foal donkeys, with the highest time occurring at 12:00 h in both seasons. The malondialdehyde (MDA) concentrations in adults (2.34 ± 0.14 nMol/L), yearlings (2.28 ± 0.19 nMol/L) and foals (3.48 ± 0.17 nMol/L) during the hot-dry season were significantly (P < 0.05) higher, when compared to the corresponding values (0.96 ± 0.09, 1.18 ± 0.10 and 1.82 ± 0.10 nMol/L, respectively) recorded during the cold-dry season. At 0.3% NaCl-concentration, the percentage haemolysis obtained during the hot-dry season in adult (90.33 ± 0.49%), yearling (91.24 ± 0.88%) and foal (97.44 ± 0.24%) donkeys were significantly (P < 0.05) higher than the corresponding values (78.53 ± 0.98, 78.67 ± 0.58 and 88.23 ± 0.47%, respectively), recorded during the cold-dry season. In conclusion, the hot-dry season induced heat stress in the donkeys, resulting in a decrease in time spent on feeding and oxidative stress, as evidenced by high erythrocyte MDA concentration and percentage haemolysis.

Influence of exposure in hyperbaric chambers on selected parameters of oxidative stress in professional divers

This study evaluated the influence of hyperbaric exposure chambers on selected parameters of oxidative stress in divers' blood. 25 healthy men (non-smoking experienced divers) ages 18-40 took part in the experiment. Subjects were exposed to hyperbaric conditions similar to those at 30 meters of depth while diving. A control group consisted of 20 healthy men who have never dived or been exposed to hyperbaric conditions. Blood was drawn from the cubital vein after overnight fasting. Superoxide dismutase (SOD-1) activity and malondialdehyde (MDA) concentration were marked in red blood cells (RBCs), carbonyl group concentration marked in serum proteins, and nitrate/nitrite concentrations were estimated in plasma. Statistically significant differences were found between the divers and the control group in MDA concentration in erythrocytes and carbonyl group concentration in serum proteins. Nitrite/nitrate concentrations in plasma plus SOD-1 activity in RBCs decreased significantly in the diver group compared with the control group. After hyperbaric exposure MDA concentration in erythrocytes increased considerably in the test group and a significant increase in SOD-1 activity was observed. A significant increase of nitrite/nitrate concentration was noted in plasma as well as an increase in the carbonyl group in serum proteins. Considerably weak enzymatic antioxidative defense was observed in the RBCs of individuals exposed to hyperbaric pressures versus those in normobary. This issue indicates that a diver's system has a larger susceptibility for negative effects from oxidative stress. The results also indicate that hyperbaric conditions can intensify reactions via free radicals.

Age-related differences in stress responsiveness of the hypothalamic-pituitary-adrenal axis of nonhuman primates with various types of adaptive behavior

Aging is characterized by disturbances in the functioning of the hypothalamic-pituitary-adrenal (HPA) axis, associated with disturbances in the adaptation processes and increase of the probability of the onset of post-stress syndrome. However, the individual features of age-related disorders stress reactivity of HPA axis have not been studied. The purpose was to study individual characteristics of the HPA axis responsiveness to acute psycho-emotional stress exposure (restraint, ASE) at different age periods on the model of the young adult and old physically healthy female rhesus monkeys that differ in their behavioral responses to stress, i.e., with depression-like and anxiety-like behavior (DAB) on the one hand and healthy standard (control) adaptive behavior (SB) on the other hand. No significant intergroup differences were observed in HPA axis responses to ASE in young animals. During aging the monkeys with SB showed reduced ACTH response to the ASE, whereas the monkeys with DAB demonstrated its increase. The old animals with DAB in response to ASE demonstrated the most pronounced HPA axis disorders, such as the highest levels of corticotrophin (ACTH), the lowest levels of dehydroepiandrosterone sulfate (DHEAS), reduced cortisol (F) levels and the highest values of the F/DHEAS molar ratio. The ratio F/DHEAS positively correlates with the malondialdehyde concentration in erythrocytes that is considered as the biomarker of oxidative stress. Thus, these data allow us to consider the old monkeys with DAB as individuals with higher vulnerability to the adverse effects of ASE. In addition, depression-like and anxiety-like behavior of aged primates under mild/moderate stress along with reduced DHEAS plasma concentration and increased values of F/DHEAS ratio can be used to identify individuals with increased vulnerability to ASE and accelerated aging.

Effect of Whole-Body Cryotherapy on Antioxidant Systems in Experimental Rat Model.

Background The purpose of this study was to verify the effect of whole-body cryotherapy (WBC) in rats on their antioxidant systems, lipid peroxidation products, and their total oxidative status at different exposure times and temperatures. Methods Antioxidants in serum, plasma, liver, and erythrocytes were evaluated in two study groups following 1 min of exposure to −60°C and −90°C, for 5 and 10 consecutive days. Results WBC increased the activity of superoxide dismutase, catalase in the group subjected to 5 and 10 days exposure, −60°C. The glutathione S-transferase activity increased in the groups subjected to 10 days WBC sessions. Total antioxidant capacity increased after 5 and 10 days of 1 min WBC, −60°C; a decrease was observed at −90°C. A decreased level of erythrocyte malondialdehyde concentration was observed at −60°C after 5 and 10 days of cryostimulation. An increased concentration was measured at −90°C after 10 days, and increase of erythrocyte malondialdehyde concentration after 5 days, −90°C. Conclusions To the best of our knowledge, this is the first research showing the effect of WBC in rats at different exposure times and temperatures. The effect of cryotherapy on enzymatic and nonenzymatic antioxidant systems was observed in the serum of animals exposed to a temperature of −60°C in comparison to control.

Circadian (about 24-hour) variation in malondialdehyde content and catalase activity of mouse erythrocytes

Lipid peroxidation is a part of normal metabolism that may cause biological molecule damage leading to the formation of several specific metabolites that include aldehydes of variable chains, such as malondialdehyde (MDA). These biological effects are controlled in vivo by a wide spectrum of enzymatic and non-enzymatic defense mechanisms among which catalase (CAT) is considered as an important regulator of oxidative stress. The present study aimed to investigate the possible relationship between the temporal patterns of the formation of MDA and the activity of CAT in the erythrocytes of mice. Twenty-four-hour studies were performed on male Swiss albino mice, 12 weeks old, synchronized to a 12:12 light: dark cycle for 3 weeks. Different and comparable groups of animals (n = 10) were sacrificed at an interval of 4 hours (1, 5, 9, 13, 17, and 21 hours after light onset (HALO)). The levels of erythrocyte MDA concentration and CAT activity both significantly (analysis of variance: F = 6.4, P < 0.002) varied according to the time of sampling under non-stressed conditions. The characteristics of the waveform describing the temporal patterns differed between the two studied variables, e.g. MDA content showing one peak (≅21 HALO) and CAT activity showing three peaks (≅9, 17, and 21 HALO). Cosinor analysis revealed a significant (adjusted Cosinor: P ≤ 0.018) circadian (τ ≅ 24 hours) rhythm in MDA level and no statistically significant rhythmicity in CAT activity. The differences and the absence of correlation between the curve patterns of erythrocyte MDA content and CAT activity under physiological conditions are hypothesized to explain that variation in lipid peroxidation may depend on several factors. Moreover, the identification of peak/trough levels of MDA accumulation in erythrocytes may reflect the degree of oxidative stress in these blood cells. In addition, the observed significant time-of-day effect suggests that, in both clinical and scientific settings, appropriate comparison of MDA production and CAT activity levels can only be achieved on data obtained at the same time of day.

Effect of methoxy polyethylene glycol-epoetin beta on oxidative stress in predialysis patients with chronic kidney disease

BackgroundThere is data in the literature indicating increased oxidative stress in chronic kidney disease (CKD). Erythropoiesis-stimulating agents (ESAs), which are commonly used to treat anemia in patients with CKD, seem to have an antioxidant action, which could be a part of nephroprotection. The aim of the current study was to investigate the effect of a long half-life ESA, methoxy polyethylene glycol-epoetin beta (Mircera), on some markers of oxidative stress in predialysis patients with CKD.Material/MethodsPeripheral blood was collected from 28 predialysis CKD patients 2 times, before Mircera treatment and after achieving target hemoglobin (Hb), and 15 healthy subjects (control group). Superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) activity in erythrocytes were measured according to commonly used methods as a function of the antioxidant defense system. To assess reactive oxygen species (ROS) production, malondialdehyde (MDA) concentration in erythrocytes and in plasma was measured according to a commonly used method.ResultsSOD, GSH-Px, and CAT activity were similar, but plasma and erythrocyte MDA concentrations were significantly higher in CKD patients before ESA treatment in comparison to the control group. SOD, GSH-Px, and CAT activity was significantly higher, but plasma and erythrocyte MDA concentrations were significantly lower, in CKD patients after ESA treatment in comparison to these patients before treatment. We did not find a significant correlation between Hb concentration and SOD, GSH-Px, and CAT activity and plasma, as well as erythrocyte MDA concentrations. Analysis of all investigated groups showed a significant negative correlation between Hb concentration and plasma MDA concentration.ConclusionsOur results suggest that treatment of anemia with methoxy polyethylene glycol-epoetin beta may inhibit oxidative stress in predialysis patients with CKD by enhancing the antioxidant defense system and reducing ROS production.

Status of lipid peroxidation and antioxidant enzymes in goats naturally infected with Babesia ovis

This study aimed to assess lipid peroxidation and antioxidant enzymes in goats naturally infected with Babesia ovis. Red blood cell count (RBC), hemoglobin (Hb) concentration, packed cell volume (PCV), malondialdehyde (MDA) concentration, erythrocyte superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) activities and total antioxidant capacity (TAC) were determined in 15 goats naturally infected with B. ovis as well as same number of healthy goats. The parasitological diagnosis was confirmed using polymerase chain reaction (PCR) analysis by amplifying a partial 18S rRNA gene sequence of B. ovis. Percentage of parasitemia varied from 0.01 to 1%. The activities of erythrocyte GSH-Px, SOD, CAT and TAC were significantly lower (p<0.05) in the infected goats than in healthy ones. MDA concentration in erythrocytes of infected goats was significantly higher in infected goats than in healthy ones (p<0.05). Severity of parasitemia showed a positive correlation with the MDA and negative correlation with PCV, SOD, CAT, GSH-Px and TAC. Also, MDA was negatively correlated with PCV, SOD, CAT, GSH-Px and TAC. The results of this study suggested that oxidative damage to RBCs may contribute to the pathogenesis of anemia in caprine babesiosis.

Levels of two oxidative stress indicators of human sickle erythrocytes incubated in aqueous extracts of Anacardium occidentale, Psidium guajava and Terminalia catappa

The present in vitro study investigated the levels of oxidative stress indicators, namely, malondialdehyde (MDA) and methaemoglobin (mHb) when sickle erythrocytes were incubated in aqueous leaf extracts of Anacardium occidentale, Psidium guajava and Terminalia catappa for 12 h. At regular time intervals of 3 h, portions of the incubation mixture were withdrawn and spectrophotometric method was used to assay for erythrocyte MDA concentrations and percent (%) mHb. The control analysis showed that erythrocyte MDA concentration increased from 2.45±0.35 to 3.13±0.59 mmol/ml (p > 0.05; p value = 0.801176). Erythrocyte MDA concentrations in the presence of the three extracts were higher than the control samples at t = 3 h (p > 0.05; p value = 0.963253). However, compared with the control sample at the given time (t), aqueous extract ofT. catappa, exhibited the highest capacity to cause reduction of erythrocyte MDA concentration [T. catappa] = 800 mg%; [MDA] = 2.89±0.33 mmol/ml; t = 12 h), representing 7.66% reduction of erythrocyte MDA concentration. Erythrocyte % mHb increased from 2.42±0.55 to 2.51±0.49% (p > 0.05; p value = 0.995171) in the control sample within the duration of 12 h. Incubation of sickle erythrocytes with aqueous extract of [P. guajava] = 800 mg% for 9 h caused reduction of Met.Hb% from 2.49±0.49% to 2.29±0.45%; p > 0.05; p value = 0.983519. Also, aqueous extract of T. catappaexhibited low capacity to cause reduction in erythrocyte %mHb. Aqueous extracts of A. occidentale,P. guajava and T. catappa exhibited variable capacities to hinder lipid peroxidation, but did not cause corresponding reduction in percent erythrocyte %mHb, as exemplified by negative correlation between the two oxidative stress indicators in the presence of T. catappa and higher concentrations of A. occidentale, P. guajava. Key words: Malondialdehyde, methaemoglobin, erythrocyte, Anacardium occidentale, Psidium guajava, Terminalia catappa.

Levels of two oxidative stress indicators of human sickle erythrocytes incubated in aqueous extracts of Anacardium occidentale, Psidium guajava and Terminalia catappa.

An in vitro study was carried out to investigate levels of oxidative stress indicators of sickle erythrocytes incubated in aqueous extracts of Anacardium occidentale, Psidium guajava and Terminalia catappa for 12 h. At regular time intervals of 3 h, portions of the incubation mixtures were withdrawn and spectrophotometric method was used to assay for levels of erythrocyte malondialdehyde (MDA) and methaemoglobin (Met.Hb%). The control analysis showed that within the experimental time, erythrocyte MDA increased from 2.45±0.35 to 3.13±0.59 mmol/ml (p > 0.05; p value = 0.801176). Erythrocyte MDA concentrations in the presence of the three extracts were higher than the control samples at t = 3 h (p > 0.05; p value = 0.963253). Compared with the control samples at the given time (t) intervals, extract of T. catappa exhibited the highest capacity to cause reduction of erythrocyte MDA ([T. catappa] = 800 mg%; [MDA] = 2.89±0.33 mmol/ml; t = 12 h). Erythrocyte Met.Hb% increased from 2.42±0.55 to 2.51±0.49% (p > 0.05; p value = 0.995171) in the control samples within 12 h. Incubation of sickle erythrocytes with extract of [P. guajava] = 800 mg% for 9 h caused reduction of Met.Hb% from 2.49±0.49% to 2.29±0.45% (p > 0.05; p value = 0.983519). Extracts of A. occidentale, P. guajava and T. catappa exhibited variable capacities to hinder lipid peroxidation, but did not cause corresponding reduction in erythrocyte Met. Hb%, as shown by negative correlation between the two oxidative stress indicators in the presence of T. catappa and higher concentrations of A. occidentale and P. guajava.

The Role of the Antioxidant Enzymes in Erythrocytes in the Development of Arterial Hypertension among Humans Exposed to Lead

The study population included employees of metal works, with significant exposure to lead (Pb) for about 20 years (mean blood lead level PbB = 43 microg/dl), divided into four groups: normotensive (Pb-normotensive), high-normotensive, first (HT-1), and second degree (HT-2) of hypertension. The control group comprised of 30 office workers with normal blood pressure and no history of occupational exposure to lead. In erythrocytes, the activity of antioxidant enzymes and lipid peroxidation (measured as concentration of malondialdehyde (MDA)) was estimated. MDA concentration, glutathione peroxide (GPx), and superoxide dimutase (SOD) activities were significantly higher in Pb-normotensive group when compared to the normotensive control. Body mass index, age, duration of exposure to lead, and PbB were higher in both hypertensive groups than in Pb-normotensive or high-normotensive groups. MDA increased in HT-1 group by 48% and in HT-2 by 72%, and the activity of GPx decreased significantly in HT-1 group, by 30% and in HT-2 by 43%. No significant differences were observed in their activity of SOD, catalase, and glutathione reductase in erythrocytes. Arterial blood pressure (both systolic and diastolic) positively correlated with body mass index (BMI), age, lead exposure duration, PbB, MDA, and negatively correlated with GPx. There was no significant correlation between BMI and MDA, BMI and GPx, age and MDA, AND age and GPx. (1) lead increases erythrocyte MDA concentration and the activity of GPx as well as SOD in normotensive subjects. (2) Among individuals exposed to lead, with arterial hypertension diagnosed, higher body mass index, age, values of blood lead level, and prolonged exposure to lead have been noticed, accompanied by intensified oxidative stress and the decrease in the activity of glutathione peroxidase in erythrocytes. The reasons for increase of blood pressure in lead exposure remain unrecognized.

Evaluation of antioxidant status and oxidative stress in cattle naturally infected with Theileria annulata

To assess the antioxidant status and oxidative stress in bovine theileriosis due to Theileria annulata blood samples were collected from 35 clinically affected cattle referred to Veterinary Teaching Hospital, School of Veterinary Medicine, Urmia University, Urmia, Iran. Complete blood count, piroplasm parasitemia percentage, erythrocyte glutathione peroxidase, superoxide dismutase, catalase and glucose-6-phosphate dehydrogenase activities, malondialdehyde concentration, osmotic fragility test and median corpuscular fragility were determined and the results were compared with those of 50 healthy controls. Of 35 affected cattle, 12 (34.28%) had severe anemia and 23 had mild to moderate anemia and parasitemia varied from 5 to 40%. The activities of erythrocyte glutathione peroxidase, superoxide dismutase and glucose-6-phosphate dehydrogenase were significantly lower ( P < 0.0001) and the activity of catalase was significantly higher in the affected cattle than in healthy ones ( P < 0.001). Malondialdehyde concentration in erythrocytes of affected cattle was significantly more than those of healthy cattle ( P < 0.001). The affected cattle showed increased fragility of erythrocytes, so that median corpuscular fragility (MCF) in affected group was significantly lower than those of healthy group ( P < 0.0001). Median corpuscular fragility showed a positive correlation with the severity of parasitemia ( r = 0.81, P < 0.0005) and a negative correlation with the activities of GSH-Px ( r = −0.78, P < 0.0001), SOD ( r = −0.71, P < 0.0005), catalase ( r = −0.53, P < 0.018) and G6PD ( r = −0.58, P < 0.0005). The results of this study suggest that oxidative damage to RBCs may contribute to the pathogenesis of anemia in bovine theileriosis.

Lipid peroxidation and antioxidant enzymes in children on maintenance dialysis

End-stage renal disease (ESRD) is associated with numerous complications, which may partly result from excessive amounts of reactive oxygen species and/or decreased antioxidant activity. The aim of the study was to evaluate lipid peroxidation (LP) in plasma and erythrocytes, erythrocyte antioxidant enzyme activity (superoxide dismutase, SOD; catalase, CAT; glutathione peroxidase, GSH-Px), and concentrations of Cu and Zn as cofactors of SOD and Se as a cofactor of GSH-Px in erythrocytes, plasma and in dialysis fluid in children with ESRD. In particular, we analyzed whether the modality of dialysis could modify oxidative stress parameters in children. To determine the influence of hemodialysis (HD) on oxidative stress, the measurements were also performed on HD children 20 min after the beginning of the dialysis session. Thirty-one patients participated in the study: group I with 10 children on continuous ambulatory peritoneal dialysis (CAPD), and group II with 21 on HD. The erythrocyte malondialdehyde concentrations (E-MDA), plasma MDA (P-MDA) and plasma organic hydroperoxide (OHP) in children from both groups were higher than in controls. E-MDA and P-MDA in HD before the session was lower compared to the values after 20 min of HD session (time T20). The activity of SOD, GSH-Px, CAT, concentrations of erythrocyte and plasma Se, Cu, Zn were lower in children with ESRD than in controls. In the HD group, the activity of GSH-Px, CAT, and levels of trace elements in erythrocytes and in plasma were diminished at time T20. In conclusion, increased oxidative stress occurs in children on maintenance dialysis, independent of dialysis modality. The activity of the enzymatic antioxidant defence system is highly reduced in red blood cells of pediatric dialysis patients. Children with ESRD exhibit lower trace element (Se, Cu, Zn) levels in plasma and erythrocytes as compared to healthy subjects. Oxidative stress is aggravated during every single HD session in children.

Activity of Glutathione Peroxidase, Glutathione Reductase, and Lipid Peroxidation in Erythrocytes in Workers Exposed to Lead

The aim of this study was to estimate the activity of glutathione peroxidase (GPx), glutathione reductase (GR), and malondialdehyde (MDA) in erythrocytes in healthy male employees of zinc and lead steelworks who were occupationally exposed to lead over a long period of time (about 15 yr). Workers were divided into two subgroups: the first included employees with low exposure to lead (LL) (n=75) with blood lead level PbB=25-40 microg/dL and the second with high exposure to lead (HL) (n=62) with PbB over 40 microg/dL. Administration workers (n=35) with normal levels of PbB and zinc protoporphyrin in blood (ZPP) in blood were the control group. The activity of GPx significantly increased in LL when compared to the control group (p<0.001) and decreased when compared to the HL group (p=0.036). There were no significant changes in activity of GR in the study population. MDA erythrocyte concentration significantly increased in the HL group compared to the control (p=0.014) and to the LL group (p=0.024). For the people with low exposure to lead (PbB=25-40 microg/dL), the increase of activity of GPx by about 79% in erythrocytes prevented lipid peroxidation and it appears to be the adaptive mechanism against the toxic effect of lead. People with high exposure to lead (with PbB over 40 microg/dL) have shown an increase in MDA concentration in erythrocytes by about 91%, which seems to have resulted from reduced activity of GPx and the lack of increase in activity of GR in blood red cells.

Correlation between clinical indicators of lead poisoning and oxidative stress parameters in controls and lead-exposed workers.

The present study was undertaken to investigate the involvement of oxidative damage in lead-induced toxicity in humans and to enlighten whether oxidative stress indicators are correlated with the known indices of lead toxicity. For these purposes, selected oxidative stress parameters along with some clinical indices of lead poisoning were determined in blood of battery plant workers and control subjects. Workers had significantly increased erythrocyte malondialdehyde (MDA) levels, catalase and glucose-6-phosphate dehydrogenase (G6PD) activities, and decreased blood glutathione:glutathione disulfide ratio compared to the controls. Increased blood lead concentrations and zinc protoporphyrin (ZPP) levels, and decreased delta-aminolevulinic acid dehydratase (ALAD) activity were used as clinical indices of lead toxicity. Statistically significant correlation between oxidative stress parameters and clinical indices implies that disrupted prooxidant/antioxidant balance might contribute to lead-induced toxicity in erythrocytes. A significant correlation was found between ALAD activity and blood lead levels in human subjects. Similarly significant correlation between ALAD activity and erythrocyte MDA concentrations was shown. Present data indicates that ALAD can serve as a valuable biomarker of oxidative stress in lead-exposed hematological system as well as being a biochemical indicator of lead exposure.

Erythrocyte superoxide dismutase and glutathione peroxidase activities, and malondialdehyde and reduced glutathione levels in schizophrenic patients.

There is abundant evidence that free radicals are involved in membrane pathology in the central nervous system and that they may play a role in neuropsychiatric disorders, including schizophrenia. In this study, we investigated erythrocyte superoxide dismutase and glutathione peroxidase activities as antioxidant enzymes, malondialdehydes as a sign of lipid peroxidation, and reduced glutathione levels in schizophrenic patients. Activities of superoxide dismutase and levels of malondialdehyde in erythrocytes were greater in all patients (n=48) and in patients with acute (n=16) and chronic schizophrenia (n=32) (p<0.001 for all patients and chronic patient group; p<0.05 for acute patient group). The activities of glutathione peroxidase were lower in patients (p<0.05 for all patients and acute patient group; p=0.051 for chronic patient group) compared with the control group. Mean erythrocyte reduced glutathione was lower in patients than in controls (p<0.05). In the patient group, erythrocyte superoxide dismutase activity was positively correlated with scales and duration of disease and erythrocyte malondialdehyde concentration. These data reveal that antioxidative defense mechanisms might be impaired in schizophrenic patients.

Oxidative damage and enhanced erythrophagocytosis in canine erythrocytes infected with Babesia gibsoni.

Oxidative damage to canine erythrocytes infected with Babesia gibsoni was investigated. B. gibsoni was cultured together with erythrocytes from normal dogs. When parasitemia reached a peak level, concentrations of both methemoglobin (metHb) and malondialdehyde (MDA), an end product of lipid peroxidation, in erythrocytes were significantly higher than at cultivation Day 0. In addition, B. gibsoni-infected dogs with high parasitemia showed significant increases of both metHb and MDA concentration in erythrocytes compared to those in uninfected dogs. Furthermore, erythrocytes from parasitized culture were more susceptible to phagocytosis by bone marrow macrophages from normal dogs than erythrocytes from the control culture. In addition, macrophages ingested not only parasitized erythrocytes but also non-parasitized cells. These results suggested that oxidative damage to erythrocytes was induced by the multiplications of B. gibsoni, and that non-parasitized erythrocytes were also exposed erythrocytes oxidative stress during the infection by B. gibsoni.