Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

A 10-month-old child with a profound deficiency of adenosine deaminase and severe combined immunodeficiency was treated for a period of 17 months with red cell and plasma transfusions containing normal amounts of the deficient enzyme. Following each transfusion, the plasma adenosine, red cell and lymphocyte ATP, urinary adenine, and urinary deoxyadenosine decreased transiently. During this period, the absolute blood lymphocyte count rose and a limited increased in the response of the lymphocytes to PHA-P was observed. Delayed hypersensitivity skin tests remained negative during the transfusion periods. A quantitative elevation of serum immunoglobulins occurred, but specific antibody formation was not elicited. In contrast to a previous report of successful therapy of ADA deficiency with red cell and plasma infusions, this patient responded poorly to enzyme replacement therapy. The difference may be related to a more profound enzyme deficiency in our patient.
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PMID:Limited effect of erythrocyte and plasma infusions in adenosine deaminase deficiency. 30 99

Deoxyadenosine, a cytotoxic purine nucleoside, is excreted in large amounts by patients with severe combined immunodeficiency disease associated with deficiency of adenosine deaminase (adenosine aminohydrolase, EC 3.5.4.4). To identify the source of the purine nucleoside, purine excretion by macrophages was studied by using mouse peritoneal macrophages as an experimental model system. Normally, macrophages excrete a large quantity of uric acid into the culture medium. However, in the presence of deoxycoformycin, a potent inhibitor of adenosine deaminase, these macrophages also excreted deoxyadenosine. Furthermore, phagocytosis of nucleated erythrocytes augmented the excretion of deoxyadenosine. Macrophages are involved in the phagocytosis of nuclei that are extruded from normoblasts during erythropoiesis and also of senescent cells in lymphoid organs. A hypothesis is proposed that macrophages of the reticuloendothelial system are a source of deoxyadenosine, which is one of the two cytotoxic purine nucleosides (the other is adenosine) apparently responsible for the suppression of immune functions in patients with adenosine deaminase deficiency.
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PMID:Purine excretion by mouse peritoneal macrophages lacking adenosine deaminase activity. 31 77

The rate of DNA synthesis in cultured diploid fibroblasts, nonmalignant human cells, is decreased by 50 microM 2'-deoxyadenosine when adenosine deaminase is inhibited and 2'-deoxyadenosine is phosphorylated to dATP. No inhibiton of DNA synthesis occurs with 100 microM adenosine under identical conditions or with 50 microM deoxyadenosine when adenosine deaminase is not blocked. Inhibition of DNA synthesis may be an important link between adenosine deaminase deficiency and severe combined immunodeficiency if the tissue culture model is relevant to lymphocyte function in man.
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PMID:Deoxyadenosine inhibits DNA synthesis in cultured human fibroblasts. 31 67

Congenital immunologic deficiencies and congenital dwarfisms represent two seemingly unrelated disorders. Here is reported the tenth case of a definite congenital and fatal syndrome associating a severe combined immunologic deficiency and a micromelic dwarfism, affecting mainly the proximal limbs, as well as an ichtyosiform and furrowed skin disorder. Although the adenosine deaminase activity has not been determined in this patient, a 4-month old boy, this syndrome seems to be different from cases of ADA negative SCID. The associated impairment of growth and immunity emphasizes once more the close genetic linkage existing between the development of the skeleton and the lymphoid tissue.
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PMID:[A fatal syndrome associating a micromelic dwarfism, an ichthyosiform skin disorder and a severe combined immunologic deficiency. Report of a case and survey of the literature (author's transl)]. 31 67

A simple, rapid (2 hours), fluorescent test for the activity of blood adenosine deaminase (ADA) is described. The test which can be performed on both heparinized and dried blood, is based on the conversion of adenosine to inosine and ammonium in the presence of ADA. The enzyme activity is visually estimated by the oxidation of NADH (fluorescent) to NAD+ (non-fluorescent) in a coupled reaction with glutamate dehydrogenase. The disappearance of fluorescence indicates ADA activity in the sample. The advantages are discussed of the use of this test for the study of the autosomal recessive severe combined immunodeficiency.
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PMID:A simple rapid fluorescent assay for adenosine deaminase activity. 31 78

Studies in three patients with severe combined immunodeficiency disease (SCID) and normal adenosine deaminase demonstrated that the combined defect of both T- and B-lymphocyte function may reflect the lack of normal maturation of thymic epithelial cells. This results in the failure of initiation of T-cell differentiation and consequent failure of T-cell dependent maturation of B-lymphocytes to an antibody-secreting stage. SCID B lymphocytes were shown to be capable of generating a specific IgM-antibody response to two T-cell-dependent antigens in vitro under either of the following conditions: (a) provision of autologous T-helper cells which were induced following incubation of precursor cells on monolayers of cultured human thymic epithelium or (b) in the presence of allogeneic T-helper cells. Specific IgM anti-ovalbumin (OA) responses were also generated in the absence of provided T-helper cells when the antigen was insolubilized (Sepharose-OA). The antibody-secreting cells and their circulating precursors carried surface IgM, HLA and Ia-like determinants and proliferated in response to antigen. Identification of this form of SCID may be important when considering therapy and provides an excellent model for the study of the T-cell-dependent acquisition and expression of B-cell immunity.
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PMID:Severe combined immunodeficiency disease: a model of T-cell dysfunction. 36 53

A causal relation between the enzyme, adenosine deaminase (ADA), and immune dysfunction is well known: patients with congenital inactivity of ADA invariably suffer of severe combined immunodeficiency. In contrast, we found in patients treated with immunosuppressive drugs increased ADA enzyme activity. Previous findings on ADA activity in acute leukemias are until now controversial. We found normal to increased ADA activity in children with acute lymphatic leukemia (ALL) and acute myeloid leukemia (AML) in remission as long as they were treated with cytostatic drugs. In the group of cured leukemics (in continuous remission after suspension of the therapeutic regimen) the ADA activities were normal. These findings do not exclude a heterogeneity within the leukemia group. They do not explain the signs of cellular immunodeficiencies well known in patients with acute leukemias.
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PMID:[Adenosine deaminase activity in blood cells; influence of cytostatic therapy in patients with acute leukemia and with renal transplants (author's transl)]. 39 66

A male infant with severe combined immunodeficiency but normal adenosine deaminase activity for whom no suitable bone marrow donor was available was given two separate grafts of both hepatic and thymic cells, the cells for each graft being taken from the same fetus aged 13 and 10 weeks respectively. Cell mediated and partial humoral immunity was restored 330 and 400 days respectively after the second transplant. No graft-versus-host reaction was observed and both red blood cell and lymphoid chimaerism could be demonstrated. The child was kept in strict bacterial isolation from the 3rd to the 537th day of life. Thirty months after the graft, the infant is in good health but has a defect of neutrophil chemotaxis and phagocytosis which requires prophylactic benzathine penicillin in addition to gammaglobulins. Fetal tissue transplantation may provide an alternative treatment for patients with severe combined immunodeficiency who do not have a histocompatible donor.
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PMID:[Restoration of mixed and severe immunologic deficiency, by fetal liver and thymus graft]. 39 3

Studies have been carried out on polymorphism of adenosine deaminase in 36 Southern African populations comprising more than 3000 individuals. The common variant allele ADA2 has been found to attain polymorphic frequencies only in those populations descended from non-indigenous (i.e. non-Negro and non-Khoisan) groups. Its presence in certain other populations at low frequencies could be ascribed to small-scale Caucasoid admixture. A deficiency of the enzyme is found in certain members of the !Kung division of the San ('Bushman'). The low levels of enzyme activity are not associated with severe combined immunodeficiency and the gene which determines them appears to be polymorphic in the !Kung and possibly in some other San populations as well as possibly in Negro populations which have received substantial contributions of San genes.
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PMID:Red cell adenosine deaminase (ADA) polymorphism in Southern Africa, with special reference to ADA deficiency among the !Kung. 47 31

Inherited deficiency of the purine salvage enzyme adenosine deaminase (ADA) gives rise to a syndrome of severe combined immunodeficiency (SCID). We have studied a 2.5-yr-old immunologically normal child who had been found to lack ADA in his erythrocytes during New York State screening of normal newborns. His erythrocytes were not detectably less deficient in ADA than erythrocytes of ADA(-)-SCID patients. In contrast, his lymphocytes and cultured long-term lymphoid cells contained appreciably greater ADA activity than those from patients with ADA(-)-SCID. This residual ADA activity had a normal molecular weight and K(m) but was markedly unstable at 56 degrees C. His residual erythrocytes-ADA activity also appeared to have diminished stability in vivo. ADA activity in lymphoid line cells of a previously reported erythrocyte-ADA-deficient!Kung tribesman was found to contain 50% of normal activity and to exhibit diminished stability at 56 degrees C. ATP content of erythrocytes from both partially ADA-deficient individuals was detectably greater than normal (12.3 and 6.1 vs. normal of 2.6 nmol/ml packed erythrocytes). However, the dATP content was insignificant compared to that found in erythrocytes of ADA(-)-SCID patients (400-1,000 nmol/ml packed erythrocytes). The New York patient, in contrast to normals, excreted detectable amounts of deoxyadenosine, but this was <2% of deoxyadenosine excreted by ADA(-)-SCID patients. Thus, the residual enzyme in cells other than erythrocytes appears to be sufficient to almost totally prevent accumulation of toxic metabolites.
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PMID:Erythrocyte adenosine deaminase deficiency without immunodeficiency. Evidence for an unstable mutant enzyme. 47 73


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