Roselia Spanevello

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

OBJECTIVESnTo evaluate the oxidative status and antioxidant defense in patients with acute lymphoblastic leukemia (ALL).nnnDESIGN AND METHODSnWe 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.nnnRESULTSnTBARS levels and serum protein carbonylation were higher in ALL patients than in controls and reduced levels of antioxidants were found in these patients.nnnCONCLUSIONnThese 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.

Activities of the enzymes that hydrolyze adenine nucleotides in platelets from multiple sclerosis patients.

Multiple sclerosis (MS) is the most common chronic disabling neurological disease in young adults. Alterations in platelet function have been observed in MS; however, the mechanism and the relevance of this blood cell disorder with regard to MS pathogenesis are not yet understood. The aim of this study was to evaluate activities of ectonucleoside thiphosphate diphosphohydrolase (NTPDase, CD39), ectonucleotide pyrophosphatase/phosphodiesterase (E-NPP), 5′-nucleotidase and adenosine deaminase (ADA) in platelets from patients with the relapsing–remitting form of MS (RRMS), as well as to analyze platelet aggregation and expression of NTPDase. The results obtained show that NTPDase, 5′-nucleotidase, E-NPP and ADA activities were decreased in platelets of RRMS patients when compared with the control group (pxa0<xa00.05). In addition, NTPDase expression in platelets was also decreased in these patients (pxa0<xa00.05); however, no differences were observed in platelet aggregation between RRMS patients and the control group. Our results suggest that the alterations in NTPDase, E-NPP, 5′-nucleotidase and ADA may have contributed to the alterations in platelet function in MS by altering the levels of nucleotides and nucleosides in the circulation.

Pre-treatment with ebselen and vitamin E modulate acetylcholinesterase activity: interaction with demyelinating agents

The ethidium bromide (EB) demyelinating model was associated with vitamin E (Vit E) and ebselen (Ebs) treatment to evaluate acetylcholinesterase (AChE) activity in the striatum (ST), hippocampus (HP), cerebral cortex (CC) and erythrocytes. Rats were divided into seven groups: I—Control (saline), II—(canola); III—(Ebs), IV—(Vit E); V—(EB); VI—(EB + Ebs) and VII—(EB + Vit E). At 3 days after the EB injection, AChE activity in the CC and HC was significantly reduced in groups III, IV, V, VI and VII (p < 0.05) and in the ST it was reduced in groups III and V (p < 0.05) when compared to the control group. At 21 days after the EB injection, AChE activity in the CC was significantly reduced in groups III, IV and V, while in groups VI and VII a significant increase was observed when compared to the control group. In the HC and ST, AChE activity was significantly reduced in groups V, VI and VII when compared to the control group (p < 0.05). In the erythrocytes, at 3 days after the EB injection, AChE activity was significantly reduced in groups III, IV, V, VI and VII and at 21 days there was a significant reduction only in groups VI and VII (p < 0.05) when compared to the control group. In conclusion, this study demonstrated that Ebs and Vit E interfere with the cholinergic neurotransmission by altering AChE activity in the different brain regions and in the erythrocytes. Furthermore, treatment with Vit E and Ebs protected against the demyelination lesion caused by EB. In this context, we can suggest that ebselen and Vit E should be considered potential therapeutics and scientific tools to be investigated in brain disorders associated with demyelinating events.

The activity and expression of NTPDase is altered in lymphocytes of multiple sclerosis patients

BACKGROUNDnMultiple sclerosis (MS) is a demyelinating neurological disease, which is presumed to be a consequence of infiltrating lymphocytes that are autoreactive to myelin proteins. ATP and adenosine contribute to fine-tuning immune responses and NTPDase (CD39) and adenosine deaminase (ADA) are important enzymes in the control of the extracellular levels of these molecules at the site of inflammation. We evaluated the activity and expression of NTPDase and adenosine deaminase (ADA) activity in lymphocytes from patients with the relapsing-remitting form of MS (RRMS).nnnMETHODSnThis study involved 22 patients with RRMS and 22 healthy subjects as a control group. The lymphocytes were isolated from blood and separated on Ficoll density gradients and after isolation the NTPDase and ADA activities were determined.nnnRESULTSnThe NTPDase activity and expression were increased in lymphocytes from RRMS patients when compared with the control group (p<0.05). In addition, a decrease in ADA activity was observed in lymphocytes from these patients when compared to the control group (p<0.05).nnnCONCLUSIONSnThe regulation of ATP and adenosine levels by NTPDase and ADA activities may be important to preserve cellular integrity and to modulate the immune response in MS.

Effect of vitamin E on ectonucleotidase activities in synaptosomes and platelets and parameters of oxidative stress in rats experimentally demyelinated

NTPDase and 5-nucleotidase activities in synaptosomes and platelets and oxidative stress parameters, such as TBARS levels, non-protein thiols and catalase activity were analyzed in rats submitted to demyelination by ethidium bromide (EB) and treated with vitamin E. The following groups were studied: I control (saline); II (canola oil); III (vitamin E); IV (EB) and V (EB and vitamin E). 2mg/kg of vitamin E were injected intraperitoneally in animals from groups III and V for seven days. After this time, the animals were submitted to euthanasia and samples were collected for biochemical assays. The results showed that NTPDase and 5-nucleotidase activities were significantly increased in synaptosomes and platelets of rats from group IV when compared with the groups I, II, III and V (p<0.05). When demyelinated rats were treated with vitamin E (group V), NTPDase activity in synaptosomes and platelets was reduced to control level, while 5-nucleotidase activity was significantly increased in relation to the control group (p<0.05). TBARS levels and non-protein thiols were significantly increased in group IV (p<0.05), while catalase activity was significantly decreased in this group when compared with the control group (p<0.05). No differences in TBARS levels, non-protein thiols and catalase activity were observed in groups I, II, III and V. These findings demonstrate that ectonucleotidase activities in synaptosomes and platelets and some parameters of oxidative stress were altered after a demyelinating event on the nervous system and that treatment with vitamin E modulated adenine nucleotide hydrolysis and altered oxidative stress parameters in this experimental condition.

Acetylcholinesterase Activity in Rats Experimentally Demyelinated with Ethidium Bromide and Treated with Interferon Beta

The ethidium bromide (EB) demyelinating model was associated with interferon beta (IFN-β) to evaluate acetylcholinesterase (AChE) activity in the striatum (ST), hippocampus (HP), cerebral cortex (CC), cerebellum (CB), hypothalamus (HY), pons (PN) and synaptosomes from the CC. Rats were divided into four groups: I control (saline), II (IFN-β), III (EB) and IV (EB and IFN-β). After 7, 15 and 30xa0days rats (nxa0=xa06) were sacrificed, and the brain structures were removed for enzymatic assay. AChE activity was found to vary in all the brain structures in accordance with the day studied (7–15–30xa0days) (Pxa0<xa00.05). In the group III, there was an inhibition of the AChE activity in the ST, CB, HY, HP and also in synaptosomes of the CC (Pxa0<xa00.05). It was observed that IFN-β per se was capable to significantly inhibit (Pxa0<xa00.05) AChE activity in the ST, HP, HY and synaptosomes of the CC. Our results suggest that one of the mechanisms of action of IFN-β is through the inhibition of AChE activity, and EB could be considered an inhibitor of AChE activity by interfering with cholinergic neurotransmission in the different brain regions.

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

BACKGROUNDnAcute 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.nnnMETHODSnThis 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.nnnRESULTSnResults 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.nnnCONCLUSIONSnThese 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.

Cyclosporine A inhibits acetylcholinesterase activity in rats experimentally demyelinated with ethidium bromide

Cyclosporine A is the major immunosuppressive agent used for organ transplantation and for the treatment of a variety of autoimmune disorders such as multiple sclerosis. In this work, we investigated the effect of the cyclosporine A on the acetylcholinesterase activity in the cerebral cortex, striatum, hippocampus, hypothalamus, cerebellum and pons of the rats experimentally demyelinated by ethidium bromide. Rats were divided into four groups: I control (injected with saline), II (treated with cyclosporine A), III (injected with 0.1% ethidium bromide) and IV (injected with 0.1% the ethidium bromide and treated with cyclosporine A). The results showed a significant inhibition (p < 0.05) of acetylcholinesterase activity in the groups II, III and IV in all brain structures analyzed. In the striatum, hippocampus, hypothalamus and pons the inhibition was greater (p < 0.005) when ethidium bromide was associated with cyclosporine A. In conclusion, the present investigation demonstrated that cyclosporine A is an inhibitor of acetylcholinesterase activity and this effect is increased after an event of toxic demyelination of the central nervous system.

Lipid peroxidation in rats treated with vincristine sulphate and nandrolone decanoate

Brain and serum lipid peroxidation was studied in rats treated with vincristine sulphate and different doses of nandrolone decanoate. Thirty rats were distributed into six groups (n=5). The treatments were applied once a week for two weeks. Sample collection was performed in the third week. Treatments during the first week were: G1 (control) - physiologic solution, G2 - vincristine sulphate (4mg/m2), G3 - physiologic solution, G4 - physiologic solution, G5- vincristine sulphate (4mg/m2), and G6 - vincristine sulphate (4mg/m2). In the second week, they were: G1 (control) - physiologic solution, G2- physiologic solution, G3 - nandrolone decanoate (1.8mg/kg-1), G4 - nandrolone decanoate (10mg/kg-1), G5 - nandrolone decanoate (1.8mg/kg-1), and G6 - nandrolone decanoate (10mg/kg-1). Lipid peroxidation increased with the isolated use of vincristine and nandrolone decanoate, and with vincristine associated to the highest dose of the ester as well. These results suggest that vincristine sulphate and nandrolone decanoate increase free radical production. Therapeutic dose of nandrolone decanoate when associated with vincristine sulphate proved to be beneficial, as it was able to protect the organism from damaging processes involved in free radical production

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 inxa0vitro 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 200xa0μM (Pxa0<xa00.05). However, in platelets GAA at the same concentrations caused a significant increase in the activities of these two enzymes (Pxa0<xa00.05). In relation to the acetylcholinesterase activity, GAA caused a significant inhibition in the activity of this enzyme in blood at concentrations of 150 and 200xa0μM (Pxa0<xa00.05), 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.