Search

The aim of the present study was to investigate the effects in vivo and in vitro of nicotine, an important immunosuppressive agent, on NTPDase and ADA activities in lymphocytes of adult rats. The following nicotine doses in vivo study were evaluated: 0.0, 0.25 and 1.0mg/kg/day injected subcutaneously in rats for 10days. The activity of the enzymes were significantly decreased with nicotine 0.25 and 1mg/kg which inhibited ATP (22%, 54%), ADP (44%, 30%) hydrolysis and adenosine (43%, 34%) deamination, respectively. The expression of the protein NTPDase in rat lymphocytes was decreased to nicotine 1mg/kg and the lymphocytes count was decreased in both nicotine doses studied. The purine levels measured in serum of the rats treated with nicotine 0.25mg/kg significantly increased to ATP (39%), ADP (39%) and adenosine (303%). The nicotine exposure marker was determinate by level of cotinine level which significantly increased in rats treated with nicotine 0.25 (39%) and 1mg/kg (131%) when compared to rats that received only saline. The second set of study was in vitro assay which the ATP-ADP-adenosine hydrolysis were decreased by nicotine concentrations 1mM (0% - 0% - 16%, respectively), 5mM (42% - 32% - 74%, respectively), 10mM (80% - 27% - 80%, respectively) and 50mM (96% - 49% - 98%, respectively) when compared with the control group. We suggest that alterations in the activities of these enzymes may contribute to the understanding of the mechanisms involved in the suppression of immune response caused by nicotine., (Copyright © 2012 Elsevier Masson SAS. All rights reserved.)

Introduction: Cervical cancer remains the second leading cause of death among women. Intraepithelial neoplasias and uterine invasive cancer are frequently associated with disturbances in coagulation and changes in the concentrations of adenine nucleotides. This work intended to analyze changes in extracellular adenine nucleotide hydrolysis and blood platelet aggregation in patients diagnosed for cervical intraepithelial neoplasia in different stages as well as uterine invasive cancer., Patients and Methods: NTPDase, E-NPP, 5'-nucleotidase, total ADA and its isoforms (ADA1 and ADA2), as well as the platelet aggregation from patients with different stages of cervical intraepithelial neoplasia (NICs I, NIC II, NIC III) and uterine invasive cancer were verified., Results: Neither ATP hydrolysis nor E-NPP activity was changed by the neoplasia stage. On the other hand, ADP and AMP hydrolysis as well as ADA activity were enhanced in NIC I group. AMP hydrolysis was also increased in the cancer group. ADA 1 was the ADA isoform found in platelets from both control and patient groups., Conclusion: Our results showed for the first time that NTPDase, 5'-nucleotidase, E-NPP and ADA are not sensible regarding the grade of neoplasia development, since no significant difference was found between the groups studied. Only ADP hydrolysis and ADA activity showed a significant enhancement in NIC I group related to the other stages possibly as a result of the beginning of the neoplasic transformation. This increase could be reflecting a body's reaction against the probable high adenosine levels. We propose for the first time that the ADA isoform present in platelets is ADA 1., (© 2012 Elsevier Masson SAS. All rights reserved.)

Background: The nucleotides and nucleosides of adenine are signaling molecules related to thromboregulation and modulation of immune responses in patients with malignancies. Thus, this study aims to determine NTPDase, 5'-nucleotidase, ectonucleotide pyrophosphatase/phosphodiesterase (E-NPP) and adenosine deaminase (ADA) activities in the platelets of patients with lung cancer., Methods: We collected blood samples from patients (n=33) previously treated for lung cancer with chemotherapy. Patients were classified as stage IIIb and IV according to the Union for International Cancer Control (UICC)., Results: Patients showed a significant decrease in the hydrolysis of adenosine diphosphate (ADP) and adenosine, whereas the adenosine monophosphate (AMP) hydrolysis and platelet aggregation were significantly increased in this group. Adenosine triphosphate (ATP) hydrolysis did not show significant results between the group of patients and the control group., Conclusions: We may suggest that ectonucleotidases as well as ADA are enzymes involved in thromboembolic events but especially here we may see that they are also directly involved in the generation of adenosine formation in the cancer patient circulation., (© 2011 Elsevier Masson SAS. All rights reserved.)

The purpose of this study was to investigate the role of ADA as additional marker of HIV infection as well as its association with other biochemical markers. This study included 55 patients, 26 being diagnosed as HIV positive and 29 patients diagnosed as HIV negative. Glucose, total protein, lactate dehydrogenase, and adenosine deaminase (ADA) activity were measured on cerebrospinal fluid (CSF). ADA activity on CSF was statistically different in HIV-seropositive subjects compared with HIV-negative subjects. The sensitivity and specificity of ADA activity on CSF was 50 and 82.76%, respectively. ADA activity was positively correlated with lactate dehydrogenase and protein in patients with HIV positive and it was negatively correlated with glucose levels. ADA determination in CSF could add information about inflammatory processes in patients with HIV infection., ((c) 2009 Elsevier Masson SAS. All rights reserved.)