Oxidative stress versus antioxidant defenses in patients with acute myocardial infarction.

Acute myocardial infarction (AMI) is a highly dynamic event, which is associated with increasing production of reactive oxygen species (ROS). The imbalance between ROS production and antioxidant defenses leads to the condition known as oxidative stress. The most widely recognized effect of increasing oxidative stress is the oxidation and damage of macromolecules, membranes, proteins, and DNA. Therefore, in this study we sought to evaluate oxidative stress and antioxidant defenses in patients with AMI. Lipid peroxidation, protein carbonyl levels, and enzymatic and nonenzymatic antioxidants were assessed in samples obtained from 40 AMI patients and 40 control patients. AMI was characterized by clinical, electrocardiographic, and laboratory criteria. The control group was divided into two groups of 20 patients: a control group with healthy patients and a risk group. Our results demonstrated an increase in substances reactive to thiobarbituric acid (TBARS) and carbonyl protein levels in the AMI and risk groups. In addition, a positive correlation was found between TBARS, carbonyl protein levels, and troponin I in AMI patients. Surprisingly, for the enzymatic antioxidant defenses, catalase and superoxide dismutase, we observed an increase in these parameters in the AMI and risk groups when compared with healthy patients. However, a decrease in nonenzymatic antioxidants such as vitamin C and vitamin E was observed in AMI patients when compared with the healthy group and the risk group. The increase in oxidative stress was probably a result of the elevation in ROS production due to the ischemic/reperfusion event that occurs in AMI, in addition to the decrease of nonenzymatic antioxidant defenses.

Enzymes that hydrolyze adenine nucleotides in platelets and polymorphisms in the alpha2 gene of integrin alpha2beta1 in patients with von Willebrand disease.

Von Willebrand disease (VWD) is one of the most common inherited bleeding diseases caused by a qualitative or quantitative deficiency of the von Willebrand factor (FvW). FvW is a multimeric glycoprotein synthesized by megakaryocytes and endothelial cells and it is present in the subendothelial matrix, blood plasma, platelets, and endothelium. This glycoprotein plays an important role in thrombus formation by initiating platelet adhesion to sites of injury as well as platelet aggregation. The aim of this study was to evaluate the activities of enzymes that hydrolyze adenine nucleotides in platelets, ristocetin-induced platelet aggregation (RIPA), and polymorphisms of the alpha2 gene of alpha2beta1 integrin from VWD patients. Platelet nucleoside triphosphate diphosphohydrolase (NTPDase), 5'-nucleotidase, and ecto-nucleotide pyrophosphatase/phosphodiesterase (E-NPP) activities were verified in 14 VWD patients. For RIPA determination, a final concentration of 1.25 mg/ml of ristocetin was used. Polymorphisms of the alpha2 gene were analyzed through PCR. Platelet NTPDase and E-NPP were decreased in VWD patients. 5'-Nucleotidase activity was not statistically significant between controls and VWD patients. RIPA was significantly reduced, with an allelic frequency of 78.57% for 807C in VWD patients. Our results indicated reduced platelet NTPDase and E-NPP activities which might be related to the low platelet adhesiveness. The prevalence of the 807C allele might account for the variability in bleeding in VWD.

Selective brain neuronal and glial losses without changes in GFAP immunoreactivity: Young versus mature adult Wistar rats.

Normal ageing results in brain selective neuronal and glial losses. In the present study we analyze neuronal and glial changes in Wistar rats at two different ages, 45 days (young) and 420 days (mature adult), using Nissl staining and glial fibrillary acidic protein (GFAP) immunohistochemistry associated to the Sholl analysis. Comparing mature adults with young rats we noted the former present a decrease in neuronal density in the cerebral cortex, corpus callosum, pyriform cortex, L.D.D.M., L.D.V.L., central medial thalamic nucleus and zona incerta. A decrease in glial density was found in the dorsomedial and ventromedial hypothalamic nuclei. Additionally, the neuron/glia ratio was reduced in the central medial thalamic nucleus and increased in the habenula. No changes were found in the neuronal and glial densities or neuron/glia ratio in the other studied regions. The number of astrocytic primary processes and the number of intersections counted in the Sholl analysis presented no significant difference in any of the studied regions. Overall, neither GFAP positive astrocytic density nor GFAP immunoreactivity showed alteration.

Previous treatment with ebselen and vitamin E alters adenine nucleotide hydrolysis in platelets from adult rats experimentally demyelinated with ethidium bromide.

Many aspects of the relationship between the demyelinating pathology and platelet function need to be elucidated. Thus, the activity of NTPDase and 5'-nucleotidase enzymes was analyzed in platelets from rats demyelinated with ethidium bromide (EB) and previously treated with ebselen (Ebs) and vitamin E (Vit. E). The animals were divided into four groups: for ebselen, the groups were: I-control (saline), II-(saline and Ebs), III-(EB) and IV-(EB and Ebs); and for vitamin E, the groups were: I - control (saline), II-(saline and Vit. E), III-(EB) and IV-(EB and Vit. E). After 3 and 21 days, the blood was collected and the platelets were separated for enzymatic assays. For the treatment with Ebs, the NTPDase activity for ATP substrate was significantly lower in groups II, III and IV (p < 0.05) after 3 days, while after 21 days, a reduction was observed in group III (p < 0.05). ADP hydrolysis was reduced in group II (p < 0.05) and increased in group IV (p < 0.05) after 3 days, while after 21 days there was an increase in group IV (p < 0.05). In the treatment with Vit. E, ATP hydrolysis was lower in groups II, III and IV (p < 0.05) after 3 and 21 days. ADP hydrolysis was increased in group II (p < 0.05) after 3 days, and in group IV (p < 0.05) after 21 days. However, 5'-nucleotidase activity was not altered by the treatments. These findings demonstrate that NTPDase activity in platelets is diminished in demyelinating events and the treatments with Ebs and Vit. E modulated adenine nucleotide hydrolysis.

Oxidative status in patients submitted to conization and radiation treatments for uterine cervix neoplasia.

BACKGROUND: Cervical cancer is a major cause of morbidity among women. We investigated the treatment effect on oxidative status from patients submitted to radiotherapy or conization surgery to high-grade SIL (squamous intraepithelial lesion) treatment, and oxidative profile from patients newly diagnosed for uterine cervix cancer, without treatment. METHODS: We determined the catalase activity in blood, reduced glutathione (GSH) in plasma, TBARS and protein carbonyl content from serum samples of the patients. RESULTS: The catalase activity, GSH levels, TBARS and protein carbonyl content had no statistical differences related to the controls, neither when the 2 treatments were compared, possibly because the antioxidant defense may be acting in the first period of the neoplasic transformation, and maybe indicating a possible arrest of the tumor cells caused by the efficiency of the treatments. In the non-treated patients, TBARS and protein carbonyl contents, GSH levels and catalase activity were shown to be increased comparing with the treated patients and compared with the controls indicating an tumor effect on oxidative profile, and the antioxidant activity been increased in the beginning of the tumor development. CONCLUSIONS: We suggest that the treatments were efficient in arrest of the tumor.

Mercury toxicity induces oxidative stress in growing cucumber seedlings.

In this study, the effects of exogenous mercury (HgCl(2)) on time-dependent changes in the activities of antioxidant enzymes (catalase and ascorbate peroxidase), lipid peroxidation, chlorophyll content and protein oxidation in cucumber seedlings (Cucumis sativus L.) were investigated. Cucumber seedlings were exposed to from 0 to 500microM of HgCl(2) during 10 and 15 days. Hg was readily absorbed by growing seedlings, and its content was greater in the roots than the in shoot. Time and concentration-dependent reduction in root and shoot length was observed at all concentrations tested, equally in the roots and shoot, at both 10 and 15 days. At 50microM HgCl(2), root fresh weight of 15-day-old seedlings increased, and at other concentrations, it reduced. For 10-day-old seedlings, reduction in root and shoot fresh biomass was observed. At 15 days, only at 50microM HgCl(2) was there no observed reduction in shoot fresh biomass. Dry weight of roots increased at 500microM both at 10 and 15 days, though at 250microM HgCl(2) there was only an increase at 15 days. There was a significant effect on shoot dry weight at all concentrations tested. Hg-treated seedlings showed elevated levels of lipid peroxides with a concomitant increase in protein oxidation levels, and decreased chlorophyll content when exposed to between 250 and 500microM of HgCl(2). At 10 days, catalase activity increased in seedlings at a moderately toxic level of Hg, whereas at the higher concentration (500microM), there was a marked inhibition. Taken together, our results suggest that Hg induces oxidative stress in cucumber, resulting in plant injury.

Ectonucleotide pyrophosphatase/phosphodiesterase (E-NPP) and adenosine deaminase (ADA) activities in prostate cancer patients: influence of Gleason score, treatment and bone metastasis.

The relation between adenine nucleotides and cancer has already been described in literature. Considering that the enzymes ectonucleotide pyrophosphatase/phosphodiesterase (E-NPP) and adenosine deaminase (ADA) act together to control nucleotide levels, we aimed to investigate the role of these enzymes in prostate cancer (PCa). E-NPP and ADA activities were determined in serum and platelets of PCa patients and controls. We also verified the influence of the Gleason score, bone metastasis and treatment in the enzyme activities. Platelets and serum E-NPP activity increased, whereas ADA activity in serum decreased in PCa patients. In addition, Gleason score, metastasis and treatment influenced E-NPP and ADA activities. We may propose that E-NPP and ADA are involved in the development of PCa. Moreover, E-NPP and ADA activities are modified in PCa patients with distinct Gleason score, with bone metastasis, as well as in patients under treatment.

Cholinesterase activities and biochemical determinations in patients with prostate cancer: influence of Gleason score, treatment and bone metastasis.

Prostate cancer (PCa) is the sixth most common type of cancer worldwide. Cholinesterase is well known as having non-cholinergic functions such as cellular proliferation and differentiation, suggesting a possible influence of cholinesterase in tumorogenesis. Thus, the aim of this study was to investigate the whole blood acetylcholinesterase (AChE) and plasma butyrylcholinesterase (BChE) activities and some biochemical parameters in PCa patients. This study was performed in 66 PCa patients and 40 control subjects. AChE and BChE activities were determined in PCa patients and the influence of the Gleason score; bone metastasis and treatment in the enzyme activities were also verified. Furthermore, we also analyzed possible biochemical alterations in these patients. AChE and BChE activities decreased in PCa patients in relation to the control group and various biochemical changes were observed in these patients. Moreover, Gleason score, metastasis and treatment influenced cholinesterase activities and biochemical determinations. Our results suggest that cholinesterases activities and biochemical parameters are altered in PCa. These facts support the idea that the drop in the cholinesterase activity and the consequent increased amount of acetylcholine could lead to a cholinergic overstimulation and increase the cell proliferation in PCa.

Enzymes that hydrolyze adenine nucleotides in patients with ischemic heart disease.

BACKGROUND: The extracellular nucleotides, ATP and ADP, as well as the nucleoside adenosine have been implicated in a great number of pathologic and physiological functions. However, extracellular adenine nucleotide levels are controlled by a complex cell surface-located group of enzymes called ectonucleotidases. We evaluated activities of enzymes that hydrolyze adenine nucleotides and nucleosides in platelets from patients with ischemic heart disease (IHD). METHODS: Sixty IHD patients were selected for the study. The activities of ectonucleoside triphosphate diphosphohydrolase (NTPDase, CD39), ectonucleotide pyrophosphatase/phosphodiesterase (E-NPP), ecto-5'-nucleotidase and adenosine deaminase (ADA) were studied in isolated platelets of these patients, as well as the platelet aggregation and NTPDase expression. RESULTS: The results show that NTPDase, ecto-5'-nucleotidase, E-NPP activities and NTPDase expression were increased in platelets of IHD patients when compared with the control group (p < 0.05). On the other hand, ADA activity and platelet aggregation were decreased in IHD patients, when compared with the control group (p < 0.05). CONCLUSIONS: The pathological condition in IHD generates alterations in ectonucleotidase activities as a compensatory organic response to thrombotic events that occur in IHD.

Oxidative stress and antioxidant status in prostate cancer patients: relation to Gleason score, treatment and bone metastasis.

Over the last decade, epidemiological, experimental and clinical studies have implicated oxidative stress in the development and progression of prostate cancer. In the present study, we evaluated the oxidative status and antioxidant defense in patients with prostate cancer (PCa) taking into consideration: treatment, Gleason score and bone metastasis. For this, we measured concentrations of plasmatic thiobarbituric acid reactive substances (TBARS), serum protein carbonylation, whole blood catalase (CAT) and superoxide dismutase (SOD) activities, as well as the plasma and erythrocyte thiol levels and serum vitamin C and E concentration. This study was performed on 55 patients with PCa and 55 healthy men. TBARS levels and serum protein carbonylation were higher in PCa patients than in controls and altered levels of antioxidants were found in these patients. CAT activity was decreased and SOD activity was higher in PCa patients when compared with controls. Non-protein thiol levels were increased, however, serum vitamin C and vitamin E content were reduced in PCa patients when compared with controls. In addition, different parameters analyzed in PCa patients based on metastasis, treatment and Gleason score showed changes in oxidative stress biomarkers and antioxidant defenses. These findings may indicate an imbalance in the oxidant/antioxidant status, supporting the idea that oxidative stress plays a role in PCa, moreover, the oxidative profile appear to be modified by bone metastasis, treatment and Gleason score.

Enzymes that hydrolyze adenine nucleotides in lymphocytes and platelets of immunosuppressed rats.

NTPDase (EC 3.6.1.5) is an enzyme that hydrolyzes extracellular nucleoside tri-and/ or diphosphates to form ATP, which can serve as a substrate for ecto-5'- nucleotidase (EC 3.1.3.5), releasing adenosine, an inhibitor of platelet aggregation and an immunosuppressant agent. In this study, the activity of enzymes that hydrolyze adenine nucleotides was investigated in lymphocytes and platelets of immunosuppressed rats. NTPDase and ecto-5'-nucleotidase activities were determined by colorimetric assay with quantification of the inorganic phosphate released. A significant increase in NTPDase activity was observed in lymphocytes (about 30% in ATP hydrolysis and 80% in ADP hydrolysis, at p<0.05 and p<0.01, respectively). In platelets, there was a significant increase in 5'-nucleotidase activity in immunosuppressed rats (p<0.01) when compared with controls. These results suggest that the hydrolysis of adenine nucleotides is modified in the immunosuppressed state, possibly to compensate for alterations that occur and to avoid the adverse effects of therapy.

Aluminum-induced oxidative stress in cucumber.

Aluminum (Al) is one of the most abundant elements of the planet and exposure to this metal can cause oxidative stress and lead to various signs of toxicity in plants. Plants are essential organisms for the environment as well as food for humans and animals. The toxic effect of aluminum is the major cause of decreased crop productivity. Thus, the objective of the present study was to analyze the effects of aluminum on the activity of antioxidant enzymes such as catalase (CAT - E.C. 1.11.1.6), superoxide dismutase (SOD - E.C.1.15.1.1) and ascorbate peroxidase (APX - E.C. 1.11.1.11), and on lipid peroxidation, electrolyte leakage percentage (ELP) and chlorophyll and protein oxidation levels in Cucumis sativus L. (cv. Aodai). Seedlings were grown at different concentrations of aluminum ranging from 1 to 2000 microM for 10 days. The increase in ELP and H(2)O(2) production observed in the seedlings may be related to the decreased efficiency of the antioxidant system at higher aluminum concentrations. The antioxidant system was unable to overcome toxicity resulting in negative effects such as lipid peroxidation, protein oxidation and a decrease in the growth of Cucumis seedlings. Aluminum toxicity triggered alterations in the antioxidant and physiological status of growing cucumber seedlings.

Changes in acetylcholinesterase (AchE) activity in lymphocytes and whole blood in acute lymphoblastic leukemia patients.

BACKGROUND: Acute lymphoblastic leukemia (ALL) is a type of cancer that affects lymphocytes and it is the most common form of cancer in children. Acetylcholinesterase (AChE) is well known as having non-cholinergic functions and has been detected in the blood and plasma of humans including in lymphocytes. Thus, we investigated whole blood and lymphocyte AChE activity in patients with ALL. METHODS: This study was performed on 72 children with ALL divided into 4 groups: newly diagnosed, remission induction, remission maintenance and out-of-treatment and one control group of 50 healthy subjects. We determined AChE activity in whole blood and lymphocytes of these patients. RESULTS: Results demonstrated that whole blood AChE activity was enhanced in the newly diagnosed group and reduced in the remission induction and remission maintenance groups in relation to the control group. For lymphocyte AChE activity we found an increase in the newly diagnosed group and a decrease in the remission induction group in relation to the control. CONCLUSIONS: These results suggest that AChE activity was altered in ALL patients. This fact may be related with the essential role played by AChE in the development of hematological disease and its contribution to the regulation of immune function.

Measurement of oxidative stress and antioxidant status in acute lymphoblastic leukemia patients.

OBJECTIVES: To evaluate the oxidative status and antioxidant defense in patients with acute lymphoblastic leukemia (ALL). DESIGN AND METHODS: We measured concentrations of plasmatic thiobarbituric acid reactive substances (TBARS), serum protein carbonylation, whole blood catalase (CAT) and superoxide dismutase (SOD) activities, as well as the plasmatic and erythrocyte thiol levels and serum vitamin E concentration. This study was performed on 80 children with ALL divided into 4 groups: just diagnosed, remission induction, remission maintenance and out-of-treatment. RESULTS: TBARS levels and serum protein carbonylation were higher in ALL patients than in controls and reduced levels of antioxidants were found in these patients. CONCLUSION: These findings may indicate a possible link between decreased antioxidants and increased levels of cells alterations due to oxidative damage, supporting the idea that there is a persistence of oxidative stress in acute lymphoblastic leukemia.

Hydrolysis of adenine nucleotides in platelets from patients with acute myocardial infarction.

OBJECTIVES: To investigate the rate of ATP, ADP and AMP hydrolysis on the surface of platelets from acute myocardial infarction (AMI) patients. DESIGN AND METHODS: Twenty-five patients diagnosed with AMI, through clinical criteria, electrocardiographic changes and increase of cardiac biomarkers, as well as 25 healthy patients were selected. The hydrolysis of ATP, ADP and AMP was verified in isolated platelets of these patients. RESULTS: The results demonstrated that an increase in ATP (54%) and ADP (45%) hydrolysis occurred in AMI patients when compared to the control group. The hydrolysis of AMP also increased by 46% in AMI patients probably leading to an enhancement in the adenosine level. CONCLUSIONS: Our results suggest an increase in nucleotide hydrolysis in platelets from AMI patients, which could be related to a compensatory organic response to thrombotic events that occur in AMI.

Effects in vitro of guanidinoacetate on adenine nucleotide hydrolysis and acetylcholinesterase activity in tissues from adult rats.

Guanidinoacetate methyltransferase (GAMT) deficiency is a disorder of creatine metabolism characterized by low plasma creatine concentrations in combination with elevated guanidinoacetate (GAA) concentrations. The aim of this work was to investigate the in vitro effect of guanidinoacetate in NTPDase, 5'-nucleotidase and acetylcholinesterase activities in the synaptosomes, platelets and blood of rats. The results showed that in synaptosomes the NTPDase and 5'-nucleotidase activities were inhibited significantly in the presence of GAA at concentrations of 50, 100, 150 and 200 microM (P < 0.05). However, in platelets GAA at the same concentrations caused a significant increase in the activities of these two enzymes (P < 0.05). In relation to the acetylcholinesterase activity, GAA caused a significant inhibition in the activity of this enzyme in blood at concentrations of 150 and 200 microM (P < 0.05), but did not alter the acetylcholinesterase activity in synaptosomes from the cerebral cortex. Our results suggest that alterations caused by GAA in the activities of these enzymes may contribute to the understanding of the neurological dysfunction of GAMT-deficient patients.