Rafael Fernandes Zanin

Apyrase and 5′-nucleotidase Activities in Synaptosomes from the Cerebral Cortex of Rats Experimentally Demyelinated with Ethidium Bromide and Treated with Interferon-β

Apyrase and 5′-nucleotidase activities were analyzed in an ethidium bromide (EB) demyelinating model associated with interferon-β (IFN-β). The animals were divided in groups: I, control (saline); II, saline and IFN-β; III, EB and IV, EB and IFN-β. After 7, 15 and 30xa0days the animals (n=5) were sacrificed and the cerebral cortex was removed for synaptosome preparation and enzymatic assays. Apyrase activity using ATP as substrate increased in groups II, III and IV (P<0.001) after 7xa0days and in groups III and IV (P<0.001) after 15xa0days. Using ADP as substrate, an activation of this enzyme was observed in group III (P<0.05) after seven and 15xa0days. The 5′-nucleotidase activity increased in group III (P<0.05) after 7xa0days and in groups II, III and IV (P<0.001) after 15xa0days. After 30xa0days treatment, no significant alteration was observed in enzyme activities. Results showed that apyrase and 5′-nucleotidase activities are altered in demyelination events and that IFN-β was able to regulate the adenine nucleotide hydrolysis.

Enhanced NTPDase and 5′-nucleotidase activities in diabetes mellitus and iron-overload model

The activity of the enzymes NTPDase and 5′-nucleotidase was studied in both diabetes mellitus and an associated model of iron-overload. Rats were divided in five groups: citrate (CC), saline (S), diabetic (D), iron-overload (IO), and diabetic iron-overload (DIO). Diabetes was induced with alloxan (150xa0mg/kg), and iron-overload was induced with iron-dextran (10 intramuscular applications of ±80xa0mg/kg). The enzymatic activities were evaluated in the platelets. The results demonstrated an increase in the activity of NTPDase with substrates ATP and ADP (60% and 120%, respectively; Pxa0<xa00.001), and 5′-nucleotidase (60%, Pxa0<xa00.001). This increase was more intense in the IO and DIO groups. The results obtained in vitro showed an activation in ATP, ADP, and AMP hydrolysis between 1xa0µM and 1,000xa0µM ferric nitrate concentrations, being more pronounced at 100xa0µM and decreasing at 1,000xa0µM. We concluded that diabetes mellitus in association with iron-overload increased the hydrolysis of adenine nucleotides in platelets, contributing to the abnormalities found in these pathological conditions.

Nucleotide degrading enzymes in platelets from uterine cervical neoplasia patients treated with conization or radiotherapy

BACKGROUNDnUterine cervical neoplasia is an important worldwide malignancy sometimes associated with thrombosis. Ectonucleotidases are membrane-bound enzymes which participate in thromboregulation by hydrolyzing adenine nucleotides in the extracellular medium. In this sense, we aimed to investigate their activity in patients with uterine cervical neoplasia.nnnMETHODSnWe evaluated NTPDase and 5-nucleotidase activities from patients previously treated for uterine cervical neoplasia with either conization or radiotherapy (RTX). These patients were divided into four groups: two conization groups (I and II) and two RTX groups (III and IV), which were further divided based on the amount of time that had passed since the conclusion of their treatment, where groups I and III were extended-remission-period groups (patients with 1 to 5 years elapsed after the conclusion of treatment), and groups II and IV were recently treated patients (treated up to three months before).nnnRESULTSnFor both conization and RTX groups, ATP and ADP hydrolysis decreased in the extended-remission groups when compared to the control and recently treated groups. On the other hand, AMP hydrolysis was decreased in all the treated groups (both conization and RTX) compared to the control. CD39 expression was decreased in extended-remission groups (I and III) when compared to the other groups.nnnCONCLUSIONSnNTPDase protects against platelet aggregation and 5-nucleotidase is more involved in the control of adenosine formation.