The effect of benign prostatic hyperplasia on total antioxidant capacity and protein peroxidation in canine prostatic fluid and spermatozoa.

The aim of this study was to evaluate the antioxidative/oxidative status of spermatozoa and prostatic fluid in dogs with benign prostatic hyperplasia (BPH) by the determination of total antioxidant capacity and protein peroxidation markers. Study was conducted on 40 intact dogs of various breeds. The dogs were assigned to two groups: BPH group (n=20) and non-affected group (n=20). The second and third fractions of the ejaculate were collected separately by digital manipulation. Total antioxidant capacity (TAC) and the concentrations of SH-groups in sperm and prostatic fluid were determined spectrophotometrically, the concentrations of bityrosine and formylkynurenine were determined using spectrofluorimetric methods. The mean values of TAC in spermatozoa and prostatic fluid were significantly lower (p<0.05), whereas the mean contents of biotyrosine and formylkinurenine were significantly higher (p<0.05) in BPH dogs compared to control dogs. There was no statistically significant difference in the content of SH group between dogs with BPH and control dogs (p>0.05). In conclusion, the results indicate that BPH in dogs is associated with reduced total antioxidant capacity and increased protein oxidation in the prostatic fluid and spermatozoa, and suggest the importance of oxidative stress in the pathogenesis of this condition. The potential role of antioxidants in the prevention and therapy of canine BPH requires further studies.

Selenium and vitamin E supplementation enhances the antioxidant status of spermatozoa and improves semen quality in male dogs with lowered fertility.

Studies showed a beneficial effect of supplementation with selenium (Se) and vitamin E on semen quality. The aim of the study was to investigate the effect of Se and vitamin E supplementation on the antioxidant status of spermatozoa and semen quality in dogs with lowered fertility. Ten dogs were supplemented daily with Se (6 µg/kg organic Se yeast) and vitamin E (5 mg/kg) per os for 60 days. Control group consisted of 10 males without the supplementation. Semen was collected on day 0, 30, 60 and 90. Sperm quality parameters were evaluated using CASA and a microscope. Concentrations of Se and vitamin E in blood as well as glutathione peroxidase (GSH-Px) activity and total antioxidant capacity (TAC) in the spermatozoa were determined. After 60 days of supplementation the concentration of spermatozoa, the majority of motility indicators and the percentage of normal morphology and live spermatozoa increased significantly (p < .05). An increase (p < .05) in concentration of Se and vitamin E in blood and GSH-Px-activity and TAC in the spermatozoa was detected. The study results indicate that Se and vitamin E supplementation for 60 days enhances the antioxidant status of spermatozoa and improves the quality of the semen in dogs with lowered fertility.

Preliminary data on possible protein markers of parturition in cows.

Parturition is one of the most important events in reproduction. Regardless of many studies, exact time for pregnancy termination and onset of parturition is impossible to determine. The aim of this study was to describe and to compare protein profile of plasma from healthy pregnant cows (n = 6) at following five time points: 2 weeks, 1 week before, at parturition, 1 week and 2 weeks after parturition to search for possible protein markers of parturition. Plasma samples were analysed by 1D and 2D electrophoresis, and selected spots were identified by mass spectrometry. Protein profile showed no uniform pattern. Seventy spots differed at least for one sampling point from the time point 2 weeks before parturition which served as reference. Thirty spots expressed higher intensity of staining 1 week as 2 weeks before parturition while 13 showed opposite relationship. Twenty two spots expressed higher intensity of staining at parturition as 2 weeks before delivery while 15 showed opposite relationship. Eighteen spots expressed higher intensity of staining 2 weeks before parturition as 1 week post-partum while 2 showed opposite relationship. Fifteen spots expressed higher intensity of staining 2 weeks before parturition as 2 weeks after delivery while 14 showed opposite relationship. Thirty-five proteins, belonging to different functional groups, were identified. Of them, 15 spots differed significantly between parturition and 2 weeks before delivery. Among them were metalloproteinase inhibitor and LDH which seem to be the most promising molecules considered as parturition markers due to their functions.

Partial biochemical characterization of Cu,Zn-superoxide dismutase extracted from eggs of hens (Gallus gallus domesticus).

Biochemical characteristics of Cu,Zn-SOD derived from hen egg white and egg yolk were determined, and compared with those of enzymes from erythrocytes of hens and SOD standard. The presence of dimer with a molecular weight of 33.38±0.34kDa, and pI of 6.30±0.15 was confirmed in samples of SOD extracted from egg yolk. Cu,Zn-SOD isolated from egg yolk had an optimum at pH 6. Average SOD activity in egg yolk was 98.5±19.5U·g-1 while in egg white reached 6.1±0.8U·g-1. Changes in SOD activity of the egg yolk during its storage for 200days were also described. FTIR analysis confirmed that the enzymatic protein described in this study was SOD, while MALDI-TOF analysis confirmed only SOD from erythrocytes. Since eggs are a cheap and easily obtainable source of SOD, this enzymatic protein could be used in food, cosmetic or pharmaceutical industries.

Extracellular matrix proteins in healthy and retained placentas, comparing hemochorial and synepitheliochorial placentas.

The placenta expresses structural and biologically active proteins. Their synthesis is mainly regulated by genomic or nongenomic signals and modulated by hormones. These protein profiles are altered during different stages of pregnancy. The biological properties of extracellular matrix (ECM) proteins were defined and described in a number of tissues including placenta. These properties enable them to be the main players in the processes of attachment or invasion into the endometrium during initial placenta formation and its timely separation after delivery and detachment. In this review, we focused on the role of ECM proteins during attachment of the placenta to the uterine wall, its timely separation, and the implications of this process on retained or pathologically attached placenta. Although the amount of published information in this area is relatively scant, some of the key proteins and processes are well defined. We focused on the available data detailing the ECM protein profiles of human (histologically thin; hemochorial) and bovine (histologically thick; epitheliochorial) placentas and compared the shared and unique ECM proteins that are relevant to placental attachment and separation.

The effect of conjugated linoleic acid supplements on oxidative and antioxidative status of dairy cows.

Dairy cows develop frequently negative energy balance around parturition and in early lactation, resulting in excessive mobilization of body fat and subsequently in increased risk of ketosis and other diseases. Dietary conjugated linoleic acid (CLA) supplements are used in dairy cows mainly for their depressing effect on milk fat content, but are also proposed to have antioxidative properties. As negative energy balance is associated with oxidative stress, which is also assumed to contribute to disease development, the present study was conducted to examine effects of CLA on oxidative and antioxidative status of lactating dairy cows. German Holstein cows (primiparous n=13, multiparous n=32) were divided into 3 dietary treatment groups receiving 100g/d of control fat supplement, containing 87% stearic acid (CON; n=14), 50g/d of control fat supplement and 50g/d of CLA supplement (CLA 50; n=15), or 100g/d of CLA supplement (CLA 100; n=16). The CLA supplement was lipid-encapsulated and contained 12% of trans-10,cis-12 CLA and cis-9,trans-11 CLA each. Supplementation took place between d1 and 182 postpartum; d 182 until 252 postpartum served as a depletion period. Blood was sampled at d -21, 1, 21, 70, 105, 140, 182, 224, and 252 relative to calving. The antioxidative status was determined using the ferric-reducing ability of plasma, α-tocopherol, α-tocopherol-to-cholesterol mass ratio, and retinol. For determination of oxidative status concentrations of hydroperoxides, thiobarbituric acid-reactive substances (TBARS), N'-formylkynurenine, and bityrosine were measured. Mixed models of fixed and random effects with repeated measures were used to evaluate period 1 (d -21 to 140) and 2 (d182-252) separately. Cows showed increased oxidative stress and lipid peroxidation during the periparturient period in terms of increased serum concentrations of hydroperoxides and TBARS, which decreased throughout lactation. During period 1, the supplemented cows had lower TBARS concentrations, which was not detectable in period 2. The other determined parameters were not affected by CLA supplementation. The obtained results show that dietary CLA supplementation in the chosen dosage, formulation, and application period had a marginal antioxidative effect in terms of lipid peroxidation in lactating dairy cows.

Differences in extracellular matrix remodeling in the placenta of mares that retain fetal membranes and mares that deliver fetal membranes physiologically.

INTRODUCTION: In mammals, placenta separation at term may involve degradation of the extracellular matrix by matrix metalloproteinases (MMPs). The activity of MMPs is modulated by TIMPs. We hypothesized that the placentas of mares that deliver fetal membranes physiologically and those that retain fetal membranes (FMR) differ in terms of histology; mRNA expression of MMP-2 and MMP-9; protein expression of MMP-2, MMP-9, and TIMP-2; and the potential activity of both MMPs. METHODS: Placenta biopsies were taken from mares (n = 9; 4 FMR, 5 controls) immediately after foal expulsion. Retention was defined as failure to expel all fetal membranes within 3 h of expulsion. All mares were monitored for time of expulsion. The degree of allantochorial/endometrial adhesion was determined in FMR mares, and biopsies from all mares were histologically examined. mRNA expression, protein immunolocalization, protein amount and potential enzyme activity were determined with RT-PCR, immunohistochemistry, Western Blotting and zymography, respectively. RESULTS: FMR mares had strong to extremely strong allantochorial/endometrial adhesion, and significantly more connective tissue in the allantochorial villi than controls. The range of MMP-2 mRNA expression levels was more than 13 times greater in FMR mares than in controls. Protein content of both MMPs and TIMP-2 differed significantly between groups. The range of potential MMP-2 and MMP-9 activity was larger in FMR mares, and MMP-2 potential activity was 1.4 times higher in controls (P = 0.02). DISCUSSION: These results indicate differences in extracellular matrix remodeling in FMR mares and controls, and suggest dysregulation of MMP expression and activation in FMR mares.

Assessment of lipid and protein peroxidation markers in non-pregnant and pregnant female dogs.

The aim of the study was to investigate oxidative stress during normal pregnancy in female dogs based on an evaluation of plasma markers for lipid and protein peroxidation. Twenty clinically healthy female dogs (10 non-pregnant and 10 pregnant) were used in the study. Blood samples from the pregnant animals were collected at 19-21, 38-40, and 56-58 days of pregnancy. Blood samples from non-pregnant female dogs were obtained between 20 and 35 days after ineffective breeding. As indicators of oxidative stress, we measured the following using spectrophotometric and spectrof- luorimetric methods: thiobarbituric acid reactive substances (TBARS), radical cations of N,N, diethylparaphenylene diamine (RC-DEPPD), sulfhydryl groups (SH groups), bityrosine and formylkynurenine. The mean plasma TBARS concentration in the pregnant dogs (0.486 ± 0.071-0.581 ± 0.191 µmol/g protein) was significantly higher (p < 0.05) than that found in the non-pregnant animals (0.274 ± 0.111 µmol/g protein). A marked, although not significant, decrease in SH group content, as well as an increase in bityrosine and formylkynurenine concentration were concurrently observed in the pregnant dogs. No significant differences were found in terms of the studied markers in the pregnant animals when comparing the values obtained during the investigated periods of pregnancy, although there was a progressive decrease in TBARS concentration and a progressive increase in RC-DEPPD, bityrosine and formylkynurenine contents. Our findings suggest that normal pregnancy in female dogs is associated with oxidative stress. Further studies are necessary to establish the physiological ranges of antioxidative/oxidative profiles in pregnant dogs and to explain if and how the intensity of oxidative stress might contribute to the risk of the complications of pregnancy.

Effects of ovariohysterectomy on oxidative stress markers in female dogs.

Numerous studies reported an increase of oxidative stress increases in both women and female laboratory animals after ovariectomy. However, there is little information about the evaluation of antioxidative/oxidative status in ovariectomized dogs. The purpose of this study was to examine the changes in oxidative stress markers after ovariohysterectomy (OHE) in female dogs. The study included eighteen healthy mongrel female dogs. Blood samples were collected immediately before surgery and 14 and 30 days after surgery. Following parameters of oxidative stress intensity were determined: the erythrocyte activity of glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) as well as the plasma concentrations of thiobarbituric acid reactive substances (TBARS), radical cations of N,N, diethylpara-phenylene diamine (RC-DEPPD), sulfhydryl groups (SH groups), bityrosine and formylkynurenine. The activity of GSH-Px increased markedly, although not significantly, 14 days after OHE and then significantly decreased at 30 days after OHE. A significant increase in plasma TBARS, bityrosine and formylkynurenine concentrations and a decrease in SH group content were concurrently noted at 30 days after surgery. Acquired results suggested that a loss of control over ROS production occurred in female dogs after OHE, which could lead to oxidative stress in the late post-operative period. In conclusion, our findings indicated that OHE is related with the risk of oxidative stress in the late period after operations. Given that oxidative stress contributes to the pathogenesis of various diseases, this may suggest an increased risk of disorders in ovariectomized female dogs; however, further studies are necessary to confirm this hypothesis.

Usefulness of DIGE for the detection of protein profile in retained and released bovine placental tissues.

INTRODUCTION: Regardless intensive research, the etiology and mechanisms of retention of fetal membranes in cows, still require elucidation. In our research approach, difference in gel electrophoresis (DIGE) and matrix-assisted laser desorption/ionization (MALDI) identification were used to obtain first results on protein profile of bovine placental membranes which were properly released or retained for more than 12 h after parturition. METHODS: Placentomes from 6 cows that released placenta and from 6 cows that retained fetal membranes were homogenized, fluorescence labeled and subjected to DIGE. RESULTS: Selected spots that significantly differed between retained and released placenta as well as spots with constant appearance were identified by MALDI. This allowed identification of the following proteins with high statistical reliability: Transforming growth factor beta 2 - high expression in maternal and fetal part of retained fetal membranes, Short transient receptor potential channel 5 -high expression in maternal part of retained and not retained fetal membranes, Rab GDP dissociation inhibitor beta - high expression in fetal part of retained and not retained fetal membranes, Proline dehydrogenase 2 - similar expression in all examined samples, Ras-related protein Rab-7b -high expression only in maternal part of not retained fetal membranes. DISCUSSION: Up to now, these proteins have not been considered as possibly important molecules for the separation/retention of fetal membranes, but their biological roles may suggest it. Further studies are necessary to establish a full profile of bovine placental proteins and define target molecules that may be involved in separation/retention of fetal membranes.

Profile of bovine proteins in retained and normally expelled placenta in dairy cows.

Tissue-specific protein profile is determined by its function, structure, intensity of metabolism and usefulness. This profile remains under hormonal control. Any disturbance in the general metabolism may be reflected in changes in both protein quantity and quality. These changes can be of low or high specificity, and some can be used as clinical markers of pathological conditions. The aim of this study was to describe and to compare the protein profile of caruncle and foetal villi of bovine placenta that was either properly released or retained. Placental tissues were collected from healthy cows, divided into releasing and retaining foetal membranes, homogenized and subjected to 1D and 2D electrophoresis. Computer-aided analysis of gel images showed essential qualitative and quantitative alterations in protein profile between tissues that were properly released and retained. Alterations concerned both the number of fractions and spots as well as the intensity of staining. This preliminary study provides a general overview of the differences in the protein profile between released and retained foetal membranes. It may allow for selecting the group of proteins or single molecules, which should be further analysed in detail as possible markers differentiating the retention of foetal membranes in cows from placentas that were released spontaneously. The continuation of the study for the identification of particular spots detected in 2D gels is necessary.

Sex- and age-dependent activity of glutathione peroxidase in reproductive organs in pre- and post-pubertal cattle in relation to total antioxidant capacity.

Antioxidative/oxidative balance is crucial for proper functioning of cells and tissues. It is suggested that this balance can be partly controlled by sex steroid hormones and in consequence can exhibit age- and sex-related dependency. The aim of present study was to describe sex- and age-related changes in the activity of glutathione peroxidase (GSH-Px) with respect to total antioxidant activity (TAC) in reproductive organs of cattle. Biological samples were collected from slaughterhouse and comprised of ovaries, uterus, testes as well as livers as reference tissue. Animals were divided into group of bulls (aged between 13 and 24 months; n = 12), cows (aged between 14 and 27 months; n = 12) and female calves (aged between 2 weeks and 2 months; n = 12). Examined parameters were determined spectrophotometrically and the presence of GSH-Px isoform was confirmed by Western blotting technique. Activity of GSH-Px in genital tissues regardless of sex was significantly higher than in livers, while TAC showed opposite relationship. The differences in antioxidative parameters between testes and mature ovaries (e.g. GSH-Px-1.42 ± 0.47 nkat/mg prot vs. 1.08 ± 0.24 and 1.15 ± 0.23) were noticed as well as in chosen values between cows and female calves. Western blotting allowed the detection of cytosolic GSH-Px in all examined tissues with molecular weight around 21 kDa as monomer and around 84 kDa as tetramer depending on conditions of electrophoresis. The results may confirm the influence and regulatory role of sex steroid hormones on GSH-Px activity because the alterations were sex and age dependent.

The presence of SOD 1 and GSH-Px in bovine retained and properly released foetal membranes.

The maintenance of antioxidative/oxidative balance is crucial for cellular and extracellular environment. That is why antioxidative enzymes express their activity in different isoforms in different cell compartments and extracellular space. The aim of study was to verify the results of previous experiment on activities of antioxidative enzymes by the determination of their enzymatic proteins in bovine placental tissues by Western blotting technique. Moreover, the presence of particular isoenzymes was detected and differentiated. Homogenates of maternal and foetal part of both properly released and retained bovine placenta were subjected to PAGE electrophoresis in non-reducing and reducing conditions and Western blotting with appropriate antibodies against superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). Electrophoresis allowed for the detection of protein bands of molecular weight related to CuZn-SOD as well as cGSH-Px isoenzymes. The reaction with appropriate antibodies confirmed this. Densitometric analysis, although semi-quantitative, allowed for the observation of trends in differences in antioxidative enzyme proteins, which may partly confirm previously described results in cases of retained and released placenta. Local antioxidative enzymatic mechanisms in bovine placental tissues are represented by CuZn-SOD and cGSH-Px, which show the changes in their expression during improper placental release.

Concentration of serum amyloid A and ceruloplasmin activity in milk from cows with subclinical mastitis caused by different pathogens.

The aim of the present study was to determine the concentration of serum amyloid A (SAA) and the activity of ceruloplasmin (Cp) in milk from cows with subclinical mastitis caused by different pathogens. Eighty-four milk samples from cows with subclinical mastitis and fourteen milk samples from healthy cows were examined. SAA concentration was determined using the commercial ELISA kit (Tridelta Development Ltd., Greystones, Wicklow, Ireland). Cp activity was assessed spectrophotometrically, using the Rice method. The results reveal that the concentration of SAA (with exception of CNS) and activity of Cp in cow milk can be regarded as markers of subclinical mastitis, irrespective of the microorganism inducing the disease. In conclusion, measurement of SAA and Cp in milk samples could be a useful method in diagnosing subclinical mastitis in cows, but the method should be adapted for field use.

The comparison of antioxidative/oxidative profile in blood, colostrum and milk of early post-partum cows and their newborns.

Act of delivery is supposed to be connected with antioxidative/oxidative imbalance not only in female but also in her newborn. The aim of the study was to compare antioxidative/oxidative profile of cows and their newborns in blood, colostrum and milk during early post-partum period. Twenty-five healthy pregnant cows and their newborns were included into study. Blood and colostrum/milk samples were obtained immediately after parturition, 24, 48 h as well as 6 and 12 days post-partum. Parameters of antioxidative defence including total antioxidant capacity (TAC) and glutathione peroxidase (GSH-Px) as well as parameters of lipid (LPI) and protein (SH) peroxidation intensity were determined spectrophotometrically. Obtained results indicated dynamic changes in values of examined parameters during time of experiment, which were significantly marked between 24 and 48 h post-partum, and the relationship between mother and her newborn. All parameters except for GSH-Px were markedly higher in blood of newborns as in their mothers. Moreover, TAC and GSH-Px in colostrum were lower as in blood of mothers and their newborns during first 24 h and showed opposite relationship later on. LPI was higher in colostrum as in plasma of mothers and their newborns during first 48 h, while SH was lower in colostrum as in plasma of examined animals. Values of antioxidative parameters increased significantly within examined period of time, while the content of SH groups tended to decrease and lipid peroxidation intensity fluctuated. Dynamics in changes of examined parameters may suggest temporary imbalance in antioxidative/oxidative status and adequate answer of organism to current challenge resulting from overproduction of reactive oxygen species. Present study may bring new knowledge into studies of post-parturient and post-natal period in cows and calves and may help preventing from diseases of this period.

The comparison of antioxidative/oxidative profile in colostrum, milk and blood of early post-partum cows during their first and second lactation.

The aim of the study was to compare antioxidative/oxidative profile in blood, colostrum and milk of early post-partum cows during their first and second lactation. A total of 19 healthy, primiparous cows were included in experiment and samples were collected during 2 years from the same animals immediately after parturition, 24, 48 h as well as 6 and 12 days later. All parameters including the activity of glutathione peroxidase (GSH-Px), total antioxidant capacity (TAC), the content of vitamin A, C as well as the contents of products of lipid and protein peroxidation were determined by the use of spectrophotometric methods. Comparing the profile within lactation, TAC and GSH-Px activity in blood showed decreasing trends, while parameters of lipid and protein peroxidation fluctuated. All examined parameters in colostrum and milk except from intermediates of lipid peroxidation exhibited increasing trends. These results which showed dynamic changes of antioxidative/oxidative profile not only in blood but also in colostrum/milk within examined period of time suggested appropriate answer of organism to current challenge. Moreover, not uniform but detectable changes between first and second lactation suggested that two consecutive lactations are not the same. Comparing first and second lactation, TAC and parameters of lipid and protein peroxidation in blood showed increasing tendency in second as first lactation while GSH-Px activity was opposite. The content of antioxidative vitamins and SH groups in colostrum/milk showed increasing tendency in second as first lactation, while TAC and content of end products of lipid peroxidation showed opposite trend, and GSH-Px together with intermediates of lipid peroxidation remained stable. Molecular and biochemical background for it require further elucidation.

Antioxidants in colostrum and milk of sows and cows.

On account of the oxidative stress conditions that may appear during parturition, colostrum should provide with not only nutritional and immunological components but also antioxidative protection of newborn. There is evidence that apart from well-known antioxidative enzymes like glutathione peroxidase, superoxide dismutase, catalase or low molecular antioxidants, proteins like lactoperoxidase (LPO), lactoferrin (LF) and ceruloplasmin (CP) may exert antioxidative properties in colostrum. The aim of present study was to determine and to evaluate LPO, LF and CP activities in colostrum and milk of sows and cows. Samples were collected from 16 healthy cows five times: immediately after parturition, 12, 24 and 48 h, and 7 days postpartum as well as from 14 healthy sows five times: immediately after parturition, 6, 12, 24 and 36 h later. Examined parameters were determined spectrophotometrically at 412, 560 and 540 nm respectively. LPO activity was higher in sows as in cows and increased significantly within examined time. LF ability to inhibit superoxide radical generation was higher in sows as in cows and increased significantly within examined time. CP oxidase activity was higher in cows as in sows and decreased significantly during experimental period. In conclusion, antioxidative defence system in colostrum shows dynamic changes that allow for providing with necessary protection from oxidative stress conditions, which may appear after parturition.

Postpartum relationship of beta carotene and vitamin A between placenta, blood and colostrum in cows and their newborns.

Carotenoids are lipophilic compounds which are involved not only in scavenging reactive oxygen species but also in many important biochemical processes. Periparturient period is supposed to be connected with oxidative imbalance which can be detected in blood of mother and newborn. Colostrum contains antioxidants which should protect newborn from stressful conditions. The aim of present study was do evaluate the relationship of beta carotene and vitamin A concentration between placenta, blood and colostrum of cows and blood of their newborns. 12 pregnant, healthy cows and their newborns were included into study. The concentration of beta carotene and vitamin A were detected in homogenates of placental tissues obtained immediately after parturition as well as in blood of mother and newborn and colostrum. Additionally blood and colostrum samples were collected 24 hours after parturition. The determinations were performed by use of spectrophotometric method at 325 and 453 nm. The concentration of beta carotene was significantly higher in fetal as in maternal part of placenta. Plasma level significantly decreased during 24 h after parturition in cows but significantly increased in calves. Colostrum level remained relatively stable during examined time. The concentration of retinol was significantly higher in fetal as in maternal part of placenta. Plasma levels, significantly higher in cows as in calves, increased significantly during 24 h after parturition in mothers but remained unchanged in newborns. Colostral concentrations increased significantly during examined period of time. In conclusion, dynamic changes in carotenoid concentrations in placenta, blood of mother and newborn as well as in colostrum that occur during 24 h after parturition may indicate the importance of antioxidative defence at this time both for cow and calf.

Maximal electroshock induces changes in some markers of oxidative stress in mice.

The oxidative/antioxidative status was investigated in maximal electroshock-induced seizures in mice, a well established model of generalized seizures in humans. Mice were given a single electroshock resulting in tonic convulsions. Total antioxidant capacity (TAC), lipid peroxidation intensity and glutathione peroxidase (GSH-Px) activity was measured spectrophotometrically in the brain, plasma and erythrocytes collected from mice sacrificed at different time points after stimulation. For comparison, sham-stimulated and subeffectively stimulated (no tonic seizures) mice were used. Tonic seizures caused an immediate increase in GSH-Px activity in the brain and during the following three hours the enzyme activity decreased below control values. Similar changes were seen after subconvulsive stimulations, however, a significant increase occurred only one hour after electroshock. A marked TAC reduction in the brain was observed three hours after subconvulsive stimulations. Nevertheless, no significant changes in TAC after tonic seizures were noted. TAC in plasma was significantly reduced three hours after both subconvulsive and convulsive stimulation. Marked reduction of lipid peroxidation intensity in the brain and plasma was recorded after both modes of stimulation. In conclusion, pronounced changes in oxidative/antioxidative status in mice following electroshock are caused by both convulsive and subconvulsive stimuli. Participation of oxidative stress in seizures and pathophysiology of epilepsy awaits further clarification.

Antioxidants in bovine colostrum.

Quality, content and properties of colostrum are crucial for the neonate and its further development. Due to essential differences between intrauterine and extrauterine environment, the neonate is exposed to oxidative stress conditions. Colostrum apart from nutrient and immunological components should contain antioxidative systems necessary for the protection against reactive oxygen species. This review describes available data on enzymatic and non-enzymatic antioxidants in colostrum. Due to the fact that the literature concerning bovine colostrum is scanty, the information based on bovine mature milk determinations as well as other species is provided. Bovine colostrum is used not only by calves, but also for the production of hyperimmunized colostrum, medicines or feed supplements. Quality of colostrum influences quality of mature milk. This is another reason, except from health of neonate, why antioxidative properties of bovine colostrum are of special importance and require further detailed elucidation.