Adenosine deaminase activity in protein-energy malnutrition

Cell-mediated immunity (CMI) was evaluated in 69 children with protein-energy malnutrition (PEM) and 20 healthy controls. Significantly decreased responses to purified protein derivative (PPD) (p < 0.02) and absolute lymphocyte count (ALC) (p < 0.01) and increased serum adenosine deaminase (ADA) activity (p < 0.001) were observed in PEM cases compared with the controls. The mean values of ALC and ADA activity in PEM patients were 85.9% and 158.7% of the normal mean, respectively. A significant negative correlation was observed between the two parameters (r=- 0.2765, p < 0.01). The CMI tests were abnormal in all three grades of PEM, except for the response to PPD in grade I, when compared with the controls. No significant differences were found between infected and uninfected PEM cases. Thus, impaired CMI was observed not only in grades II and III but also in grade I PEM patients and the concomitant infection did not affect its status. However, ADA activity demonstrated a more pronounced change than the other tests.     

Adenosine deaminase in progressive systemic sclerosis

The aim of the present study was to confirm the increase of adenosine deaminase (ADA) activity in progressive systemic sclerosis (PSS), described by Sasaki & Nakajima, and to compare plasma ADA activity of patients in different stages of the disease. Enzyme activity was measured with a colorimetric assay. The 48 patients were subdivided into 3 groups: subgroup 1 (n = 10), disease still limited to the skin; subgroup 2 (n = 21), involvement of the skin and oesophagus; and subgroup 3 (n= 17), involvement of the skin and multiple internal organs. ADA levels were highest in subgroup 3. However, the difference with respect to subgroup 2 did not reach statistical significance. Subgroup 1 was different from controls and subgroups 2 and 3 (p<0.001). Our results confirm that ADA activity is increased in PSS, and that this finding is observed even in the early stages of the disease process. We speculate that the increase in ADA, a well-known marker of T-cell activation, might be an indicator of disease activity in PSS, in the beginning as well as during phases of exacerbation in later stages of the disease.     

Serum erythrocyte and leukocyte adenosine deaminase activities in patients with vivax malaria in Turkey

Adenosine deaminase (ADA) activities in serum samples, erythrocytes, leukocytes and plasma hemoglobin concentrations were investigated in 50 patients with vivax malaria and compared with control group. ADA activity was determined by Bertholet reaction. Student's t-test and correlation analyses methods were used for statistical analyses. Serum ADA activity in patients with vivax malaria 49.20 +/- 29.02 IU/I, in control 21.15 +/- 8.04 IU/I (p = 0.005), erythrocyte ADA activity in patients 2.91 +/- 1.23 U/gr Hb, in control 1.65 +/- 0.59 U/gr (p = 0.001), leukocyte specific ADA activity in patients 26.23 +/- 20.21 U/mg protein, in control 25.84 +/- 9.19 U/gr Hb were determined (P > 0.05). Plasma hemoglobin concentration in patients 29.25 +/- 28.10 ml/dl, in control 9.80 +/- 13.14 mg/dl were also determined. There is no significant correlation among mentioned parameters. Erythrocyte purine salvage pathway is accelerated by Plasmodium to provide preformed purine source which can not be synthesized by Plasmodium to provide preformed purine source which can correlation between plasma hemoglobin concentration and serum ADA activity suggests that increased serum ADA activity may develop secondarily to the disease independently from the hemolyses. No higher ADA activity level than expected value of leukocytes may reflect immunosuppression of leukocytes.     

Adenosine deaminase activity in serum and pleural effusions of tuberculous and non-tuberculous patients

In a retrospective study Adenosine deaminase (ADA), was assayed in 86 serum samples and 12 pleural fluid samples of patients with pulmonary tuberculosis. Serum and pleural fluid ADA levels were also examined in a group of 38 non-tuberculous patients with pleural effusion. Highly significant increases in both serum and pleural fluid ADA levels were noted in tuberculous patients when compared to both control enzyme cut-off values and non-tuberculous pleural effusion patients. Negative Ziehl-Nielsen staining for acid fast bacilli and Purified Protein Derivative skin test results were obtained in 32.3% and 11.1% of the examined patients respectively. All these patients showed significantly elevated serum or pleural fluid ADA levels. It is hereby suggested that serum and pleural fluid ADA levels can in conjunction with other tests, serve as a marker in patients of pulmonary tuberculosis.     

Surface expression of adenosine deaminase in mitogen-stimulated lymphocytes

Adenosine deaminase (ADA) expression on the surface of mitogen-stimulated lymphocytes was studied by flow cytometry. The gate for lymphocytes was located by cell size (forward scatter), cytoplasmic complexity (side scatter) and by expression of the markers CD2, CD4, CD8 and CD19. After mitogenic proliferation two populations appeared, one corresponding to non-stimulated cells, and the other consisting of larger cells which showed relatively high expression of adenosine deaminase on their surface. The increase was similar to that observed for CD71 expression, and paralleled the increase in 3H-thymidine incorporation. There was a correlation between ADA and CD71 expression (r = 0.92 for phytohaemagglutinin (PHA) and 0.97 for pokeweed mitogen (PWM)). These results suggest a role for ecto-adenosine deaminase in lymphocyte proliferation and/or triggering.     

Adenosine deaminase deficiency in adults

Adenosine deaminase (ADA) deficiency typically causes severe combined immunodeficiency (SCID) in infants. We report metabolic, immunologic, and genetic findings in two ADA-deficient adults with distinct phenotypes. Patient no. 1 (39 years of age) had combined immunodeficiency. She had frequent infections, lymphopenia, and recurrent hepatitis as a child but did relatively well in her second and third decades. Then she developed chronic sinopulmonary infections, including tuberculosis, and hepatobiliary disease; she died of viral leukoencephalopathy at 40 years of age. Patient no. 2, a healthy 28-year-old man with normal immune function, was identified after his niece died of SCID. Both patients lacked erythrocyte ADA activity but had only modestly elevated deoxyadenosine nucleotides. Both were heteroallelic for missense mutations: patient no. 1, G216R and P126Q (novel); patient no. 2, R101Q and A215T. Three of these mutations eliminated ADA activity, but A215T reduced activity by only 85%. Owing to a single nucleotide change in the middle of exon 7, A215T also appeared to induce exon 7 skipping. ADA deficiency is treatable and should be considered in older patients with unexplained lymphopenia and immune deficiency, who may also manifest autoimmunity or unexplained hepatobiliary disease. Metabolic status and genotype may help in assessing prognosis of more mildly affected patients.     

Properties of an affinity-column-purified human deoxycytidylate deaminase

Deoxycytidylate deaminase was purified about 7000-fold to homogeneity from a human source (HeLa cells). The final step in the purification employed an affinity column, which increased the specific activity of the enzyme from the previous step by 500-fold. Similar to most other dCMP deaminases, this enzyme is allosterically regulated by microM levels of dCTP and dTTP. However, unlike the other enzymes the most dramatic allosteric responses occur at substrate levels of 0.1 mM dCMP or less, where at least a 10-fold increase in activity is effected by dCTP. The enzyme is particularly sensitive to inhibition by dTTP with 50% inhibition being obtained at 1.5 x (10(-6) M in the absence of dCTP. Antibody to the human enzyme did not cross-react with a dCMP deaminase induced in Escherichia coli by T4-bacteriophage, nor did antibody to the phage-induced enzyme cross-react with the human deaminase. A potential transition-state analogue of the substrate, 2'-beta-D-deoxyribose-pyrimidin-2-one 5'-phosphate was prepared, and found to inhibit dCMP deaminase competitively with a Ki of 1.2 x 10(-8) M.     

Deficiency of adenosine deaminase not associated with severe combined immunodeficiency

The 12-year-old Kung ("Bushman') boy from South West Africa who has marked deficiency of red cell adenosine deaminase has been found to have 2 to 3% of enzyme activity in red blood cells, 10 to 12% in leukocytes, and 10 to 30% in cultured fibroblasts. The enzyme has ADA 1 electrophoretic mobility: SV40 transformation of cultured fibroblasts caused a decrease of "tissue ADA' and an increase in "red cell ADA' isozymes. A battery of investigations revealed that the child has normal humoral and cellular immunity. A family study showed that a sibling had the same level of red cell ADA and the parents had intermediate levels. Studies of the Kung population from which the child comes have shown that the allele responsible for the condition, and which we designate ADA8, is polymorphic.     

Estrogen induces adenosine deaminase gene expression in MCF-7 human breast cancer cells: role of estrogen receptor-Sp1 interactions

Adenosine deaminase (ADA) gene expression is induced by 17beta-estradiol (E2) in MCF-7 human breast cancer cells, whereas the antiestrogens 4'-hydroxytamoxifen and ICI 182,780 exhibit partial estrogen receptor (ER) agonist/antagonist and antagonist activities, respectively. Previous studies have shown that the -211 to +11 region of the ADA gene promoter contains six GC-rich sites (I-VI) that bind Sp1 protein, and these elements are required for high basal expression. In transient transfection studies with pADA211, which contains the -211 to +11 ADA gene promoter linked to a bacterial chloramphenicol acetyl transferase (CAT) reporter gene, E2 and tamoxifen (but not ICI 182,780) induced CAT activity. Ligand-induced transactivation was observed only in cells cotransfected with expression plasmids for wild-type ER or HE11, which does not contain the DNA-binding domain of the ER. Cotransfection with HE15 and HE19, which contain the DNA-binding domain and activation function-1 (AF-1) and AF-2 of the ER, respectively, did not result in E2-induced activity. Subsequent deletion analysis of the ADA gene promoter showed that Sp1 binding site IV (-79 to -73) was primarily responsible for hormone responsiveness. ER activation of ADA gene expression is another example of an E2-induced gene that is dependent on ER/Sp1 interactions with a site-specific GC-rich motif.     

Studies on the amount and location of the tRNA and 5-S rRNA genes in Tetrahymena pyriformis GL

The occurrence of a deficiency of adenosine deaminase (ADA) activity in some patients with severe combined immunodeficiency suggests a possible relationship between the activity of ADA and the aberration of the immune system. To help delineate the function of ADA in the immune response we have examined its role in monocyte maturation. When incubated in vitro, peripheral blood monocytes transformed, within 3 days, to macrophagea as assessed by phase-contrast microscopy and an increase in the specific activity of the lysosomal enzyme acid phosphatase. The specific activity of ADA increased as much as ninefold, reaching a peak after the 1st day in culture, while the activities of other enzymes involved in the purine salvage pathway were not altered. Sucrose density ultracentrifugation of extracts prepared immediately after the isolation of monocytes revealed the presence of two forms of ADA with molecular weights of approximately 30,000 and 110,000. The increase in ADA specific activity during monocyte cultivation correlated with an increase in the activity of the smaller molecular species. A specific inhibitor ADA, erythro-9-(2-hydroxy-3-nonyl) adenine, prevented the increase in acid phosphatase activity, as well as the morphological changes associated with the monocyte maturation. These data suggest a role for ADA in monocyte to macrophage maturation. In view of the central role of macrophages in immune function, this observation may relate to the association of combined immunodeficiency and a deficiency of this enzyme.     

Central inhibitory effect of adenosine deaminase on carotid blood flow increase at high pressure

Carotid blood flow in rats was measured by implanted transit-time ultrasonic flowprobes throughout hyperbaric experiments conducted up to 70 bar (7 MPa) with a helium-oxygen hyperoxic (PO2 = 400 mbar) mixture. Before the hyperbaric experiment, an intracerebroventricular (ICV) injection of phosphate saline-buffered solution (PBS) or adenosine deaminase (ADA, 100 U.ml-1) in PBS was performed. Throughout the hyperbaric experiment carotid blood flow increased with ambiant pressure in PBS-treated rats. Conversely, the increase in carotid blood flow was attenuated by ADA treatment. These results suggest that the increase in carotid blood flow at high ambiant pressure could result from an increase of adenosine concentration in the rat brain.     

An adenosine deaminase (ADA) allele contains two newly identified deleterious mutations (Y97C and L106V) that interact to abolish enzyme activity

Genetic deficiency of the purine salvage enzyme adenosine deaminase (ADA) results in varying degrees of immunodeficiency, ranging from neonatal onset Severe Combined Immunodeficiency (SCID) to an adult onset immunodeficiency disorder. Multiple different mutations have now been identified in these immunodeficient patients. Additional mutations, initially identified in healthy individuals, abolish ADA in erythrocytes but retain 10-80% of activity in non-erythroid cells ('partial deficiency mutations'). In general, severity of disease correlates inversely with the amount of residual ADA expressed by the mutant enzymes and directly with the accumulation of the toxic metabolites deoxyATP and deoxyadenosine. We report two newly identified mutations (Y97C and L106V), both carried on the same allele of an immunodeficient patient who was diagnosed prenatally and successfully transplanted with haploidentical bone marrow. Based on the ability of mutant cDNAs to express ADA in vitro , the L106V mutation resulted in activity similar to 'partial' mutations (30% of normal) while the Y97C mutation resulted in detectable but markedly reduced activity (1.5% of normal). However, the presence of both mutations on the same allele virtually abolished detectable enzyme activity. Analysis of the crystallographic structure of ADA to understand the marked deleterious effect of the Y97C mutation suggested a previously unappreciated role of salt bridges in the catalytic mechanism of ADA. The patient was also heteroallelic for a previously described deletion of the promoter and exon 1. Testing of additional patients in whom we had not identified a mutation on the second allele revealed presence of this deletion in three of four patients tested. This deletion is therefore relatively common, accounting for 10% of almost 100 chromosomes studied by this and other laboratories, but is easily missed by currently used methods of mutation detection. Lastly, the finding of two mutations on the same allele that interact to reduce residual enzyme function emphasizes hazards in evaluating potential genotype-phenotype correlations in individuals analyzed only for the presence of single specific mutations.     

Mucosal adenosine deaminase activity and gastric ulcer healing

Adenosine deaminase activity was studied in gastric corpus mucosa close to an ulcer crater. It was found that 6 weeks of therapy with ranitidine was accompanied by a decrease in enzyme activity in the mucosa around healed ulcers and an increase around those which failed to heal. The different activities of adenosine deaminase in the vicinity of healed and unhealed ulcers may indicate its possible role in peptic ulcer healing.     

Increased nitric oxide deactivation by polymorphonuclear leukocytes in patients with intermittent claudication

PURPOSE: Local activation of polymorphonuclear leukocytes (PMNLs) is considered an important aspect of the pathogenesis of intermittent claudication, although concrete mechanisms of their effects on circulatory homeostasis in peripheral atherosclerotic disease remain unclear. This study evaluated the ability of PMNLs to deactivate nitric oxide (NO), a key regulator of regional circulation, as a possible factor determining PMNL involvement into ischemic disorders in patients who have intermittent claudication before and after vascular reconstruction. METHODS: A total of 57 patients who had peripheral occlusive disease in an aortofemoral segment before surgical treatment (group 1) and 65 patients who had similar occlusive lesions and other clinical and demographic data 6 to 12 months after undergoing inflow vascular reconstruction (group 2) were examined. All patients from group 2 had anatomically patent grafts; their satisfaction and level of function after surgical treatment were assessed by a five-point questionnaire. The sex- and age-matched control group included 35 subjects. NO activity was bioassayed by measuring its ability to increase cyclic guanosine monophosphate (cGMP) accumulation in rat fetal lung-cultured fibroblasts (RFL-6 cells). The ability of PMNLs to deactivate NO was characterized as the percent decrease in NO-induced cGMP accumulation in RFL-6 cells. RESULTS: Stimulated PMNLs caused inhibition of the activity of authentic NO; accumulation of cGMP induced by sodium nitroprusside was not affected. PMNLs from patients with peripheral atherosclerotic disease either before or after vascular reconstruction had a more marked capacity of NO inactivating than the cells from healthy subjects. For both groups of patients, levels of PMNL-induced NO deactivation were higher for patients with diabetes, and especially both diabetes and arterial hypertension. For both groups of patients, there was no correlation between levels of PMNL-induced NO deactivation and resting ankle-brachial indexes (ABIs). In contrast, close correlation was revealed between levels of PMNL-induced NO deactivation and postexercise ABIs and percent decrease in resting ABIs after exercise in patients evaluated either before or after surgical treatment. CONCLUSIONS: The ability of stimulated PMNLs to deactivate NO is elevated in peripheral occlusive disease and may be implicated in the pathogenesis of intermittent claudication. In patients who underwent successful recanalization of magistral arteries, levels of PMNL-induced NO deactivation remained higher than in control subjects. The increase in the ability of PMNL to deactivate NO positively correlated to ABI decreases after exercise in patients with peripheral occlusive disease either before or after surgical treatment.     

Epidemiologic and actual importance of entero-hemorrhagic E. coli in Northern Bavaria (1996)

OBJECTIVES: To compare peripheral type 1 (T1) and type 2 (T2) T cell activities in rheumatoid arthritis (RA) patients with that found for osteoarthritic (OA) patients and healthy controls and to correlate peripheral T1/T2 cell activity in RA with parameters of the disease. METHODS: Peripheral blood mononuclear cells were isolated from patients with RA (n = 66), OA (n = 19), and healthy controls (n = 15). Primary T cell activity in these mononuclear cells was enhanced by means of anti-CD3/anti-CD28, which mimicks stimulation of T cells by activation of the T cell receptor and a major co-stimulatory signal. Interferon gamma (IFN gamma) production and interleukin 4 (IL4) production in the three groups were quantified as measures of T1 and T2 cell activity, respectively, and compared. Serum tumour necrosis factor alpha (TNF alpha), erythrocyte sedimentation rate (ESR), C reactive protein (CRP), and joint destruction assessed radiographically of RA patients were determined as parameters of disease activity and correlated with T1/T2 cell activity. RESULTS: Peripheral T cells from RA patients produced significantly less IFN gamma and more IL4 than T cells from both age and sex matched OA patients and healthy controls. Moreover, in RA patients both a decrease in IFN gamma and an increase in IL4 production correlated with an increase in serum TNF alpha, ESR, CRP, and joint destruction. CONCLUSIONS: These results suggest a role for differential T cell activity in RA. In view of the intra-articular T1 cell predominance the results might be explained by selective T1 cell migration into the joint or peripheral suppression of T1 cell activity.     

Adenosine deaminase and A1 adenosine receptors internalize together following agonist-induced receptor desensitization

A1 adenosine receptors (A1Rs) and adenosine deaminase (ADA; EC 3.5.4. 4) interact on the cell surface of DDT1MF-2 smooth muscle cells. The interaction facilitates ligand binding and signaling via A1R, but it is not known whether it has a role in homologous desensitization of A1Rs. Here we show that chronic exposure of DDT1MF-2 cells to the A1R agonist, N6-(R)-(phenylisopropyl)adenosine (R-PIA), caused a rapid aggregation or clustering of A1 receptor molecules on the cell membrane, which was enhanced by pretreatment with ADA. Colocalization between A1R and ADA occurred in the R-PIA-induced clusters. Interestingly, colocalization between A1R and ADA also occurred in intracellular vesicles after internalization of both protein molecules in response to R-PIA. Agonist-induced aggregation of A1Rs was mediated by phosphorylation of A1Rs, which was enhanced and accelerated in the presence of ADA. Ligand-induced second-messenger desensitization of A1Rs was also accelerated in the presence of exogenous ADA, and it correlated well with receptor phosphorylation. However, although phosphorylation of A1R returned to its basal state within minutes, desensitization continued for hours. The loss of cell-surface binding sites (sequestration) induced by the agonist was time-dependent (t1/2= 10 +/- 1 h) and was accelerated by ADA. All of these results strongly suggest that ADA plays a key role in the regulation of A1Rs by accelerating ligand-induced desensitization and internalization and provide evidence that the two cell surface proteins internalize via the same endocytic pathway.     

Chemiluminescence of peripheral blood leukocytes and activity of an inflammatory process in juvenile chronic arthritis (JCA)

The oxidative metabolites have been implicated in the aetiology and pathology of rheumatoid arthritis. In our work we endeavoured to deal with polymorphonuclear leukocytes (PMNLs) ability to generate oxygen free radicals (OFRs). PMNLs metabolic activity was assessed by the means of chemiluminescence (CL) method. We observed significantly higher PMNLs metabolic activity in children suffering from JCA in comparison to the healthy group. Greater activity of the rheumatoid process was accompanied by an increased PMNLs activity. The results constitute another piece of evidence confirming the role of PMNLs in the pathogenesis of JCA.     

Isolation of a bioactive Ca(2+)-mobilizing complex lipid from bovine vitreous body

We have been undertaking the gene therapy for a 6 year-old boy with ADA deficiency and performed 11 cycles of the infusion of the peripheral T cells transduced with retroviral vector LASN since August 8th 1995. The percentage of the peripheral blood lymphocytes carrying the transduced ADA gene has remained stable at 10% to 20% since the 4th infusion. ADA enzyme activity in his circulating T cells increased to levels comparable to 1/3 of a heterozygous carrier individual and was associated with increased T lymphocytes counts and improvement in both humoral and cellular immune function. The results obtained in this clinical study support the usefulness of T lymphocyte-directed gene transfer in the treatment of ADA deficiency.     

The effect of Opisthorchis on the manifestations of herpesvirus type 2 in an experiment and their possible participation in the mechanism of the occurrence of primary liver cancer

In a 4 month study, a group of 16 patients with stable renal graft function receiving triple immunosuppressive therapy including cyclosporin A (Cy A) were investigated for the levels of calcium, magnesium and zinc in erythrocytes. The patients were randomized to be converted to the new microemulsion formulation (Sandimmun Neoral) in a 1:1 fashion (n = 8) or to continue with the classical formulation (Sandimmun) (n = 8). The concentrations of creatinine, phosphate, alkaline phosphatase activity, calcium, magnesium and zinc were measured twice a month in blood plasma. The concentration of calcium, magnesium and zinc in erythrocytes was also measured. The concentration of magnesium in blood plasma and erythrocytes during the study showed no deviation from normal values. The level of zinc in erythrocytes was almost twice as high as in normal healthy controls and was not dependent on Cy A formulation. Calcium content in erythrocytes of patients receiving Sandimmun was 27.6% higher than in healthy persons. Conversion of the patients to Sandimmun Neoral normalized the calcium concentration in erythrocytes and caused a transient increase of calcium levels in blood plasma.     

Remarkably high rate of molecular evolution of ruminant placental lactogens

Adenosine deaminase (ADA) is a deaminating enzyme consisting of isozymes ADA 1 and ADA 2. We measured the activities of total ADA, ADA 1 and ADA 2 in serum obtained from 42 patients with Parkinson's disease (PD). Patients were divided into 10 cases of stage I, 20 of II, 11 of III and 1 of IV according to the clinical stages described by Hoehn and Yahr. The total and ADA 2 activities were significantly higher in patients as compared with normal controls (p < 0.01, respectively). However, this study did not detect any tendency for elevated total ADA or its isozyme activities with advance in clinical stages described by Hoehn and Yahr. ADA and ADA 2 are thought to have important roles in the regulation of the immune function. On the other hand, recent reports have suggested that immunological abnormality may be responsible for the developing of PD. Our results also suggest that high serum ADA activity may be involved in the pathogenesis of PD through the alteration of the immune function.