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

The activity of adenosine deaminase (ADA) was measured in thymus and spleen subpopulations separated by peanut agglutinin (PNA) of melanoma B-16 C57BL bearing mice and normal age-matched C57BL mice. Groups of 10 mice were used each time and the experiments were repeated 6 times. The adenosine deaminase activity in the PNA+ thymocytes of B-16 bearing mice was about 2.5 times lower than that of the normal C57BL mice while the ADA activity in the PNA+ fraction of spleen of the B-16 melanoma bearing mice was 2.5 times higher. These results demonstrate that the tumor burden probably induces a different redistribution and traffic of lymphocytes from one lymphopoietic organ to another. This traffic can also explain the thymus involution and spleen enlargement found in the B-16 mice.
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PMID:Adenosine deaminase activity in lymphocyte subpopulations of B-16 melanoma and normal C57BL bearing mice. 652 25

Mice were given constant infusions of the adenosine deaminase inhibitor, 2'-deoxycoformycin, by i.p. implantation of microosmotic pumps, delivering the compound at a rate of 0.16 mg hr-1 kg-1. In accordance with published data, we observed that adenosine deaminase in most tissues was nearly completely inhibited. In addition, the S-adenosylhomocysteine hydrolase activity decreased slowly and showed a half-life in liver of about 4 hr. The rate and extent of the inactivation were highest in spleen. The amounts of adenosine, 2'-deoxyadenosine, S-adenosylhomocysteine, and S-adenosylmethionine were determined in treated animals and control animals. The tissue levels of adenosine and, to a lesser degree, S-adenosylhomocysteine and S-adenosylmethionine were critically dependent on the procedure used for processing the tissues. Lowest concentrations were observed when the organs were frozen in situ by liquid nitrogen. Treatment with 2'-deoxycoformycin induced no or a moderate increase in tissue content of adenosine and S-adenosylhomocysteine, whereas the amount of 2'-deoxyadenosine increased markedly, especially in spleen and thymus. 2'-Deoxycoformycin treatment caused an increase in adenosine and 2'-deoxyadenosine, but not S-adenosylhomocysteine, in serum of mice.
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PMID:Effect of 2'-deoxycoformycin infusion on S-adenosylhomocysteine hydrolase and the amount of S-adenosylhomocysteine and related compounds in tissues of mice. 660 64

The level of adenosine deaminase (ADA) activity was investigated in various populations of IL 2-dependent, cultured cytotoxic T lymphocytes (CTL), from bulk cultures as well as from CTL lines (CTL-A and CTL-B types). The study of C57BL/6 derived, cytotoxic bulk cultures yielded the following mean values of ADA activity: 12,500 U/mg in the cortical, immature region of the thymus, 1500 U/mg in the immunocompetent, cortisone-resistant medullary thymocytes, and 2000 U/mg in the T cell population from the spleen. These results are in agreement with previous studies on separated T lymphocyte populations of known origin and further indicate that a fall in ADA activity accompanies T cell maturation. ADA activity was measured in C57BL/6-derived CTL-A lines obtained from the thymic and splenic bulk cultures. All lines were characterized by a very low level of ADA activity, compared with the T cell bulk cultures freshly initiated from the thymic medulla or from the spleen, and to a variety of T tumor lines established in long term culture. Some showed undetectable ADA activity (less than or equal to 20 units/mg), whereas others maintained significant activity (50 to 500 U/mg). No correlation was found between the residual ADA activity level and the killing activity, at the time of the enzyme assay. Identical properties were observed for CTL-B cloned lines of various genetic backgrounds. These results suggest that the level of ADA activity of the CTL in the mouse is lower than the average value of mature T cells of the thymic medulla, and might constitute a differentiation marker specific to the CTL population. A possibility remains that low ADA activity levels in these CTL lines may be the consequence of an extinction of the ADA gene during in vitro growth, as it is observed for the cytotoxic activity itself. In either case, a low ADA activity level is a remarkable property of IL 2-dependent CTL clones, when compared to various established T tumor lines, which exhibit high and stable ADA levels during long term in vitro growth (5000 to 15,000 U/mg).
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PMID:Lack of adenosine deaminase activity in cultured murine cytotoxic T lymphocytes. 660 94

The prenatal diagnosis of severe combined immunodeficiency (SCID) was made in three fetuses by staining fetal blood obtained at fetoscopy with a panel of monoclonal antibodies. There were less than 100 T cells/mm3 of fetal blood in these three cases compared to 2,500/mm3 in 14 immunologically normal fetuses. Cells bearing the cortical thymocyte antigen (NA1/34) were not detected in any of the normal or affected fetal blood samples. Two of the affected fetuses were also homozygous for a deficiency of adenosine deaminase (ADA) with undetectable levels of red cell ADA. All three affected fetuses were aborted and postmortem tissue was obtained in two cases. In both of these cases the thymus was markedly hypoplastic and contained no lymphoid cells. One of these fetuses was homozygous for ADA deficiency and the virtual absence of T cells or thymocytes during the second trimester of pregnancy indicates that placental access to the maternal circulation does not prevent damage to the T lineage stem cells in this disease. Prenatal diagnosis of SCID has previously only been possible in patients with a defined metabolic defect such as ADA deficiency, but these studies indicate that prenatal diagnosis now may be offered for most at risk pregnancies.
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PMID:Prenatal diagnosis of three cases of severe combined immunodeficiency: severe T cell deficiency during the first half of gestation in fetuses with adenosine deaminase deficiency. 661 May 9

In the determination of whether human thymus-leukemia-associated antigen (HThy-L) is a low-molecular-weight form of adenosine deaminase (ADA), both HThy-L and ADA were found to have the same molecular weight of 45,000 as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The antigen and enzyme displayed a phenomenon of complete identity in immunodiffusion and a high degree of cross-reaction in a competitive radioimmunoassay for HThy-L or ADA. When tested for adenosine-deaminating activity, HThy-L was nearly as active as purified low-molecular-weight ADA from erythrocytes. However, HThy-L and ADA differed in their capacity to combine with the complexing protein isolated from human kidney. Apparently, HThy-L represents a thymic isoenzyme of ADA and is the first antigen to be associated with differentiation of hematopoietic cells for which a functional activity is established.
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PMID:Identification of human thymus-leukemia-associated antigen as a low-molecular-weight form of adenosine deaminase. 676 72

A commercial preparation of calf adenosine deaminase (calf ADA) was further purified by affinity chromatography and used for immunization of rabbits. The resulting anti-calf-ADA sera reacted by immunodiffusion with both calf and human ADA, and precipitated about 90% of radiolabeled enzyme isolated from human thymus tissue. Moreover, ADA activity was detected in the pellets formed by immunoprecipitation of unlabeled human enzyme by anti-calf-ADA sera. These antisera were successfully used for the immunomorphologic localization of ADA in human thymus tissue and in lymphoid cell preparations. The anti-calf ADA sera could also be used for the immunofluorescent detection of enzyme in rat and mouse thymocytes. The utilization of anti-calf-ADA serum for immunochemical and immunomorphologic detection of enzyme provides a valuable and sensitive reagent for the identification of ADA-positive cells in humans and several other species.
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PMID:Detection of human, rat and mouse adenosine deaminase by immunochemical and immunomorphologic methods using antiserum to calf enzyme. 679 62

The growth of allogeneic ascites hepatoma is accompanied by involution of the thymus, leukemoid response and anemia. Tumor cells disseminate throughout the body appearing in many organs including the spleen, liver, bone marrow and lymph nodes. The activity of adenosine deaminase and the adenosine deaminase/purine nucleosidephosphorylase ratio decrease in the host thymus as well as in the cellular elements of the spleen. The above phenomena reflect the impairment of lymphocyte differentiation and presumably contribute to the decreased efficiency of the host immune response.
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PMID:[Morphologic and biochemical changes in the lymphoid and hematopoietic tissues of rats with Zajdela hepatoma]. 679 89

The distribution of adenosine deaminase (ADA) and purine nucleoside phosphorylase (PNP) activities in lymphoid organs and lymphocyte subpopulations in mice, and the effect of phytohemagglutinin P (PHA-P) and concanavalin A (Con A) on the enzyme activities were studied. ADA activity was distributed equally in cells from all organs used and no mouse strain differences were observed. In contrast, PNP activity varied with the mouse strain, being highest in C57BL/6 mice and lowest in BALB/c mice, and with the organ in ICR mice, being high in peripheral blood lymphocytes and spleen lymphocytes, low in mesenteric lymph node cells and absent or very weak in thymus cells. T and B lymphocytes were prepared from spleen of ICR mice. High ADA activity was found in both T and B lymphocytes, whereas PNP activity in the T lymphocytes was about one-third of that in the B lymphocytes. PNP activity in thymus cells was increased to the normal level of T lymphocytes in the spleens by cultivation without stimulant. The development of PNP activity in thymus cells was partially inhibited by Con A but was not affected by PHA-P. ADA activity in thymus cells was enhanced by in vitro stimulation with PHA-P but not with Con A. In contrast, in spleen lymphocytes the development of ADA activity was enhanced by stimulation with PHA-P and Con A, and that of PNP activity was enhanced by PHA-P but not by Con A.
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PMID:Purine metabolic enzymes in lymphocytes. I. Adenosine deaminase and purine nucleoside phosphorylase activities in mouse lymphocyte subpopulations. 680 69

The inhibition of S-adenosylhomocysteine hydrolase and accumulation of dATP in thymus, spleen and other tissues of mice treated with the adenosine deaminase inhibitor coformycin were studied in parallel with the competence of thymocytes and spleen leucocytes to undergo mitogen-induced transformation. Newborn mice were lethally sensitive to daily injections of coformycin, 0.2 mg/kg, whereas adult mice were not. Developmental profiles of enzymes of nucleoside metabolism showed adenosine deaminase and purine nucleoside phosphorylase to be greatest in thymus around day 20 and to decrease for animals older than 60 days. The most notable change was a 3-fold increase in spleen leucocyte adenosine deaminase activity between days 10 and 30. Adenosine deaminase activity was reduced to less than 10% of normal in tissues of newborns treated with coformycin for 12-14 days. S-Adenosylhomocysteine hydrolase was also reduced to 5-40% of normal with no evidence of tissue specificity. Both thymocytes and erythrocytes of coformycin-treated mice accumulated dATP whereas spleen leucocytes did not. For coformycin-treated mice, spleen leucocyte and thymocyte response to concanavalin A (Con A) was reduced to 20 and 60% of controls respectively. Coformycin, 3.6 microM, also potentiated the in vitro toxicity of adenosine and deoxyadenosine toward thymocytes or spleen leucocytes by approximately an order of magnitude. Our observations are consistent with dATP being involved in impairment of thymocyte responsiveness; however, it appears unlikely that either dATP elevation or S-adenosylhomocysteine hydrolase inhibition is involved in the mechanism of impairment of spleen leucocyte response by coformycin.
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PMID:S-adenosylhomocysteine hydrolase activity, deoxyadenosine triphosphate accumulation, and competence of thymocyte and spleen leucocyte response to mitogens in coformycin-treated mice. 686 Mar 59

A fourteen-year old female presented with a mediastinal mass and pleural effusion. A diagnosis of a poorly differentiated lymphocytic lymphoma was made from a lymph node biopsy. Fluid from a pleural tap contained numerous lymphoblasts; 91.5% of these lymphoblasts had a thymus leukemic antigen. At presentation, although morphologically normal, no adenosine deaminase (ADA) activity could be demonstrated in her peripheral blood lymphocytes. Lysates of her lymphocytes mixed with lysates of lymphocytes with known ADA activity resulted in ADA activity that was greater than expected. With disappearance of tumor following the institution of therapy, ADA activity appeared in her lymphocytes and the above phenomenon disappeared.
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PMID:Transient stimulatory adenosine deaminase activity in peripheral lymphocyte lysates from a case of T-cell lymphoma. 689 85


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