Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.4.4 (adenosine deaminase)
 5,136 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

T-cell acute lymphoblastic leukemia is an aggressive disease that responds poorly to "standard" therapy designed for the more common B-lineage ALLs in childhood. The principles of this "standard" therapy were derived from empiric clinical trials. Thus, it is not surprising that the therapy that had the greatest impact on survival in the group as a whole would be found to be most successful for the most common subset of patients. T-cell malignant lymphoblasts share many biologic features that set them apart from the more common B-lineage lymphoblasts. Some of these biologic features suggest therapeutic approaches that should be particularly successful in treating patients with T-cell leukemia. The use of aggressive, multiple-agent "pulse" chemotherapy has been shown through empiric trials to have relative efficacy in T-cell lymphoblastic leukemia, presumably because of the rapid generation time and high growth fraction. Future studies will (1) determine the optimal dose and schedule of cytosine arabinoside needed to exploit the increased Ara-CTP accumulation in T-cell blasts, (2) determine the efficacy of a new agent, deoxycoformycin, an inhibitor of adenosine deaminase, to exploit the biochemical phenotype of T-cell blasts, and (3) assess the ability of conjugated anti-T monoclonal antibodies to deliver a cytotoxic agent, thus exploiting unique antigenic determinants at the cell surface. As more is learned about the biology of T-cell malignancies, further treatment strategies may be suggested to exploit the new features that are discovered. Similarly, it is hoped that the unique features of the B-lineage leukemias will suggest treatment strategies that will improve survival in those patients as well. Certainly, improved survival has already been achieved in the case of the B-cell leukemias and Burkitt's lymphomas, and improvement may also be possible for the pre-B and early pre-B phenotypes of lymphoblastic leukemia.
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PMID:Treatment of T-lineage acute lymphoblastic leukemia. 226 86

The relationship between the intracellular levels of DNA polymerase alpha (DP-alpha), adenosine deaminase (ADA) and lactate dehydrogenase (LDH) and the degree of malignancy of human lymphomas was investigated. Twelve non-neoplastic lymph nodes and 88 malignant lymphomas were examined. For non-Hodgkin's lymphomas (NHL) the low or high grade of malignancy was established according to three classifications: the Rappaport, the Kiel and the Working Formulation for Clinical Usage, with the latter also recognizing an intermediate grade group. Non-neoplastic lymph nodes had significantly lower levels of all the three enzymes than those found in high-grade malignant NHL (the P value ranged from less than 0.02 to less than 0.001). Hodgkin's disease, a slowly evolving neoplasia, showed lower levels of DP-alpha (P less than 0.001) and ADA (P less than 0.001), but not of LDH, than high-grade NHL. Among NHL, whatever classification was used, the low-grade malignant lymphomas had significantly lower levels than the high-grade ones for all the three enzymes (P less than 0.005 or P less than 0.001). The intermediate-grade group of the Working Formulation differed from the high-grade group for DP-alpha (P less than 0.01) and ADA (P less than 0.02) but not for LDH. It differed from the low-grade group only for ADA (P less than 0.005). Lymphoblastic and Burkitt's lymphomas were the groups with the highest levels of the three enzymes. Among low-grade lymphomas very low values were found in the histological entities defined as DLWD in the Rappaport classification, CLL and lymphoplasmacytoid immunocytoma in the Kiel classification and small lymphocytic (group A) in the WF. The levels of all enzymes in these histotypes were always significantly different from the other low-grade histotypes, and from the intermediate-grade ones of the WF. In the Kiel classification polymorphous lymphoplasmacytoid lymphoma, recently recognized as a group with a quite aggressive clinical course, was characterized by high levels of all three enzymes.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Relation between enzymatic activities and the degree of malignancy of human lymphomas. 404 77

Enzyme activity measurements are of great relevance to the classification and biochemical characterization of the various types of leukemias, but they have been much less studied in solid lymphoid tumors. The authors report investigations in human lymphomas. The levels of the following enzymes were determined: terminal deoxynucleotidyl transferase (TdT), deoxyribonucleic acid polymerase alpha (DP alpha), adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP), thymidine and uridine kinases (TK and UK, respectively), and thymidine phosphorylase (ThPh). Moreover, cytochemical investigations were done in the group of Burkitt's lymphoma (BL) and lymphoblastic lymphoma (LL), and ultrastructural studies were performed in seven of the nine LL of this series. These results were obtained: (1) TdT (90 cases) was highly specific for LL; eight of nine LL were positive, and all other histologic types were negative; the only TdT-, acid esterase (AcE) positive, nonconvoluted LL was probably related to TdT- normal medullary thymocytes, and had an unfavorable clinical course with resistance to a vincristine-and-prednisone-including treatment; (2) ADA (61 cases) could distinguish clearly between the high levels of LL and the low levels found in any other group of lymphomas; among LL, the highest values were found in T-cell-derived neoplasias, and the lowest value in a periodic acid-Schiff (PAS) positive, acid phosphatase negative case that showed the presence of large nucleoli at the ultrastructural analysis, a finding that is unusual for LL and possibly related to a more immature differentiation stage; (3) PNP (39 cases) values alone were not clinically relevant, but together with ADA levels, a subset of T-LL with high ADA:PNP ratio could be selected among LL; (4) DP alpha (61 cases), and TK and UK (37 cases) were found in concentrations reflecting the malignancy of the non-Hodgkin's lymphoma, and were more elevated in the high-grade malignant lymphomas; (5) ThPh (34 cases) was always elevated in Hodgkin's disease, but low in Burkitt's lymphoma and LL; thus, they had a high TK:ThPh ratio that could be useful in predicting clinical response to thymidine treatment. The authors think that taken together, multiple enzyme determinations could be useful in the characterization of human lymphomas.
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PMID:Multienzymatic analyses of human malignant lymphomas. Correlation of enzymatic data with pathologic and ultrastructural findings in Burkitt's and lymphoblastic lymphomas. 642 36

We describe a patient with severe combined immunodeficiency because of aberrations in adenosine deaminase (ADA) who despite adequate replacement with polyethylene glycol-linked ADA (PEG-ADA) for 13 years developed Burkitt's lymphoma. Although treatment corrected the metabolic abnormalities caused by ADA deficiency, it failed to fully restore cellular immunity.
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PMID:Burkitt's lymphoma in a patient with adenosine deaminase deficiency-severe combined immunodeficiency treated with polyethylene glycol-adenosine deaminase. 1758 99