Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.5.4.17 (adenosine deaminase)
 5,206 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Many reports have described the relationship of adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) activities with the immunological subclasses of acute lymphoblastic leukemia (ALL). The clinical significance of these enzymes in leukemias is not yet completely understood. We performed a study in 83 children with untreated ALL to establish the relationships of ADA and PNP to clinical outcome, in vitro drug resistance and differentiation stage of B-cell lineage ALL. ADA and PNP activities were determined radiochemically. In vitro resistance to 6-thioguanine (6-TG) was determined with the MTT assay. ADA activity was not different between proB- and cALL cases but decreased in the sequential differentiation stages cALL----preB-ALL----B-ALL. The PNP level was not different between the four stages of B-lineage ALL. Patients with cALL/preB ALL with low ADA activities had a significantly poorer probability of survival (p = 0.005) than patients with high ADA levels. Patients with cALL/preB ALL with low PNP activities showed a non-significant trend for a poorer prognosis (0.05 less than p less than 0.10) than patients with a high PNP level. Low ADA and PNP activities were not related to in vitro resistance to 6-TG. We conclude that ADA decreases and PNP remains constant in sequential differentiation stages of B-lineage ALL. Patients with precursor B-lineage ALL with low activities of ADA have a poorer prognosis than those with high activities of these enzymes. No relationship could be detected between ADA or PNP activity and resistance to 6-TG.
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PMID:Adenosine deaminase and purine nucleoside phosphorylase in childhood lymphoblastic leukemia: relation with differentiation stage, in vitro drug resistance and clinical prognosis. 159 2

Activities of enzymes of the purine metabolic pathway, adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP), and 5'-nucleotidase (5'-N), were investigated in the lymphoblasts of a patient with B-cell acute lymphoblastic leukemia. These lymphoblasts exhibited increased ADA activity and diminished activities of both PNP and 5'N' as compared to normal lymphocytes as well as non-T, non-B leukemia cells. This enzymatic pattern is identical to that which has been described in T-cell leukemic lymphoblasts and differs from that which has been observed in the malignant cells of undifferentiated B-cell lymphomas. These data suggest that there is biochemical heterogeneity within the spectrum of B-cell malignancies. Furthermore, inhibitors of ADA may be of use in those B-cell lymphoid neoplasms that exhibit increased ADA activity.
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PMID:Lymphoblast purine pathway enzymes in B-cell acute lymphoblastic leukemia. 626 97

Leukemic cells incubated in vitro with 2'-deoxyadenosine (dAdo) plus an inhibitor of adenosine deaminase, 2'-deoxy-coformycin (DCF), show different metabolic responses depending on the histologic and immunologic type of the leukemia. Leukemic cells were obtained from 54 patients with acute lymphoblastic leukemia (ALL), 9 with myeloid or nonlymphoblastic leukemia, 3 with chronic lymphocytic leukemia (CLL), and 3 with lymphoma. There was a wide variation in the LD50, the concentration of dAdo that caused 50% inhibition of the incorporation of 3H-thymidine into cells in the presence of 20 microM DCF. T-cell leukemia specimens were much more sensitive to dAdo than were specimens of pre-B-ALL and null-ALL. In leukemic cells that had been incubated with 14C-dAdo plus DCF, a good correlation was observed between the LD50 and the ratio of 14C-deoxyATP to ATP (correlation coefficient for the fit to a hyperbola = 0.853). The accumulation of deoxyATP by the leukemic cell specimens was correlated best with the activity of ecto-ATPase, less well with cytoplasmic 5'-nucleotidase and deoxyadenosine kinase, and poorly with adenosine deaminase and ecto-5'-nucleotidase. The clinical response to DCF therapy of a patient with T-ALL and another with pre-B-ALL was consistent with the in vitro metabolic response of their cells to DCF and dAdo.
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PMID:Biochemical correlates of the differential sensitivity of subtypes of human leukemia to deoxyadenosine and deoxycoformycin. 628 41

A prospective study was done to assess the clinical utility of terminal deoxynucleotidyl transferase (TdT) and adenosine deaminase (ADA) assays in adult leukemia with a lymphoid phenotype. The study population consisted of 58 patients with adult lymphoblastic leukemia (ALL) at onset, 12 with lymphoblastic lymphoma, 15 with acute unclassifiable leukemia (AUL), and 30 with lymphoid or mixed acute phase of Philadelphia chromosome-positive (Ph' +) chronic myelogenous leukemia (CML). TdT was present in all cases of T-ALL, in 90% of non-T, non-B ALL, and absent in B-ALL; the ADA activity was significantly higher (P less than .01) in T-ALL. TdT was found in 75% of lymphoblastic lymphomas, in 78% of lymphoid, and in 50% of mixed CML transformations; higher ADA activity correlated with TdT positivity in AUL and CML blastic transformations (P less than .001). TdT-positive ALL had a better chance of response to therapy than TdT-negative ALL (P less than 0.01), but survival was not statistically different. TdT was undetectable in the peripheral blood of patients with ALL in complete remission and within the normal range in bone marrow (0.1%-8% of nucleated cells); median ADA activity was as in control subjects. Relapsing ALL patients had TdT and ADA enzymatic activities as before therapy; TdT immunofluorescence test (IF) was positive in 69% of bone marrow and in 100% of CNS relapses. Twenty percent of TdT-positive ALL at onset became TdT-negative in bone marrow at relapse. TdT IF test was instrumental in detecting meningeal leukemia but neither TdT nor ADA could be used as indicators of complete remission or impending relapse because TdT-positive cells were present in normal marrows and wide fluctuations of TdT IF values and of ADA activity were observed in remission.
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PMID:Clinical utility of terminal deoxynucleotidyl transferase and adenosine deaminase determinations in adult leukemia with a lymphoid phenotype. 658 63

Peripheral blood, bone marrow and/or lymph nodes of 77 patients with T- and B-ALLs/lymphomas were characterized for their surface membrane marker profiles using flow cytometry and fluorescence microscopy. Purine metabolism enzyme activities were compared with membrane immunophenotypes. T and B-ALLs/lymphomas subtypes were defined by the expression of surface membrane antigens detected by the monoclonal antibodies. Based on immunophenotyping we found the following characteristic marker profiles: in T-ALL-CD7, CD2, CD1, CD5, CD3, CD4, CD8, CD38, CD71; in T-NHL-CD7,CD2,CD3,CD4,CD5,CD6; in pre-B ALL-CD10, CD19, CD24, HLA-DR, CD34, in B-ALL-CD19, CD20, CD24, HLA-DR, SmIg with kappa or lamda light chains; in B-ALL-weak SmIg, kappa or lambda, CD19, CD20, CD24, CD5, HLA-DR; in B-NHL-CD19, CD20, CD22, CD24, CD5, more intensive SmIg, kappa or lambda. The cells of leukemic cases tended to have more immature phenotypes than those of lymphoma cases. Analysis of purine metabolism enzyme activities showed that there was a correlation between the values of adenosine deaminase (ADA) and purine nucleoside (PNP) and various types of T- and B-ALLs/lymphomas. ADA levels in B-NHL and B-CLL were lower than those in normal cells, while ADA level in T-ALL, T-NHL, pre-B-ALL and B-ALL was higher (the average 185,92,73,63 pkat. 10(-6)cells, respectively). ADA activity was significantly different between lymphocytes of control group and T-ALL(p<0.01), between T-ALL and T-NHL(p<0.05), between T-NHL and B-NHL(p<0.05) and between T-ALL and B-NHL(p<0.05). PNP activities were lower to those in normal cells. ADA/PNP ratio increased mostly in T-ALL, less in T-NHL, pre-B-ALL and B-ALL (10.8 and 5.3 and 2.2, and 2.0 respectively). ADA/PNP ratio was significantly different between T-ALL and pre-B-ALL(p<0.05) and between T-ALL and B-NHL(p<0.05).
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PMID:A comparison of some leucocyte differentiation markers and the adenosine deaminase and purine nucleoside phosphorylase values in B and T cell leukemias and lymphomas. 859 72

The posttranscriptional RNA editing by the type 1 adenosine deaminase acting on RNAs (ADAR1), expressed as p110 and p150 isoforms, is important for both physiological and pathological processes. Their expression and significance in leukemias remain unknown. Here, we investigated the expression of ADAR1 in Chinese pediatric acute leukemias by real-time PCR and Western blot. The results showed that significant high expression of p110 was detected in leukemias, especially in B-ALL, whereas a slight increase of p150 could be observed. Furthermore, the decrease of p110 expression was observed in B-ALL patients achieving complete remission. Moreover, among prognostic risk groups in ALL, the highest expressions of p110 and p150 were detected in standard-risk group, whereas their lowest expressions were in high-risk group. This observation was further confirmed in comparisons between good and poor prognostic groups based on prognostic related clinical features. These results demonstrated that ADAR1 isoforms showed different expression patterns, suggesting that they might play different roles in pediatric leukemias. Our results will help us for the better understanding of RNA editing, exploring the potential target for the treatment, and making prognostic evaluation in childhood leukemias.
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PMID:Abnormal expression of ADAR1 isoforms in Chinese pediatric acute leukemias. 2131 40