Comparative Assessment of Two Strategies for Interpreting Tumor Markers in Ascitic Effusions.

BACKGROUND/AIM: There are two strategies for the interpretation of tumor markers (TM) in fluid effusions: i) high cut-off and ii) fluid/serum ratio (F/S) and low cut-off. The objective of this study is to compare these two strategies and to determine whether diagnostic accuracy improves by the identification of possible false positives using Adenosine deaminase (ADA), C reactive protein (CRP) and % of polymorphonuclear cells (%PN). PATIENTS AND METHODS: We studied 157 ascitic fluids, 74 of which were malignant. ADA, CRP and %PN were determined in ascitic fluid, and Carcinoembryonic antigen (CEA), Cancer antigen 72-4 (CA72-4), Cancer antigen CA19-9 and Cancer antigen 15-3 (CA15-3) in both fluid and serum. RESULTS: The strategy of high cut-off showed 59.5% sensitivity at 100% specificity. The F/S strategy showed 75.7% sensitivity at 95.2% specificity. Subclassifying cases with ADA, CRP and %PN negative showed 67.5% sensitivity at 100% specificity for high cut-off and for the F/S strategy was 81.7% sensitivity at 98.7% specificity. CONCLUSION: The strategy of F/S with negative ADA, CRP and %PN allow the best interpretation for TM in the ascitic fluid.

Assessment of adenosine deaminase (ADA) activity and oxidative stress in patients with chronic tonsillitis.

To emphasize the effectiveness of adenosine deaminase (ADA) enzyme, which has important roles in the differentiation of lymphoid cells, and oxidative stress in patients with chronic tonsillitis. Serum and tissue samples were obtained from 25 patients who underwent tonsillectomy due to recurrent episodes of acute tonsillitis. In the control group, which also had 25 subjects, only serum samples were taken as obtaining tissue samples would not have been ethically appropriate. ADA enzyme activity, catalase (CAT), carbonic anhydrase (CA), nitric oxide (NO) and malondialdehyde (MDA) were measured in the serum and tissue samples of patients and control group subjects. The serum values of both groups were compared. In addition, the tissue and serum values of patients were compared. Serum ADA activity and the oxidant enzymes MDA and NO values of the patient group were significantly higher than those of the control group (p < 0.001), the antioxidant enzymes CA and CAT values of the patient group were significantly lower than those of the control group (p < 0.001). In addition, while CA, CAT and NO enzyme levels were found to be significantly higher in the tonsil tissue of the patient group when compared to serum levels (p < 0.05), there was no difference between tissue and serum MDA and ADA activity (p > 0.05). Elevated ADA activity may be effective in the pathogenesis of chronic tonsillitis both by impairing tissue structure and contributing to SOR formation.

Enzyme-regulated unmodified gold nanoparticle aggregation: a label free colorimetric assay for rapid and sensitive detection of adenosine deaminase activity and inhibition.

Based on enzyme-regulated unmodified gold nanoparticle aggregation, a visual and homogeneous assay of adenosine deaminase (ADA) activity without any other coupling enzymes, aptamers or additional modifications has been developed. The present strategy is simple, cost-effective, high throughput, selective and sensitive for ADA with a detection limit of 0.8227 U L(-1).

Studies on the adenosine deaminase-catalyzed conversion of adenosine and nucleoside prodrugs by different capillary electrophoresis modes.

Four kinds of fast and efficient capillary electrophoresis modes, i.e., immobilized enzymatic reactor (IER), electrophoretically mediated microanalysis (EMMA), capillary zone electrophoresis (CZE), and micellar electrokinetic chromatography (MEKC), were first developed to study the adenosine deaminase (ADA)-catalyzed conversion of adenosine and nucleoside prodrugs, which is critical for releasing prodrugs into the intracellular compartment for phosphorylation. The enzyme-activated prodrug approach is a strategy that has been successfully employed to improve physicochemical and pharmacokinetic properties of potential therapeutic agents, especially in the search for antiviral nucleoside analogues. Adenosine, amino-ddG, and amino-D4G could be converted by ADA to different extents under our experimental conditions. Steady-state parameters K(m), V(max), and k(cat) were also determined. The substrate efficiencies (k(cat)/K(m)) of adenosine, amino-ddG, and amino-D4G were 0.19±0.01, 0.047±0.005, and 0.017±0.010 µM(-1) s(-1), respectively. The enzymatic reaction could be performed at a nanoliter scale and all manipulation steps were combined into a fully automated assay in on-line modes, which opened the possibilities of high-throughput screening of large libraries of synthetic nucleoside analogues for biological activity and a relative mechanism study of nucleoside and its analogues.

Assessment of mycobacteremia detection as a complementary method for the diagnosis of tuberculosis in HIV-infected patients.

The purpose of this investigation was to assess the usefulness of mycobacteremia detection in human immunodeficiency virus (HIV) patients with suspected tuberculosis. The study included 47 patients with suspected tuberculosis and confirmed HIV infection. A first blood sample was incubated in a BACTEC 9050 MB system, while white blood cells isolation was performed on a second blood specimen before incubation in a BACTEC MGIT 960 system. The third specimen was taken from the affected organs of each patient according to their clinical profile. Twelve (25.5%) patients were positive for mycobacterial infection identified by any of the methods used. Ten (21.2%) were positive for Mycobacterium tuberculosis and 2 (4.3%) for M. avium. Six patients were diagnosed by the culture of specimen from affected organs only, whilst three other patients were positive exclusively for blood cultures. Three additional patients were diagnosed by both methods. Four patients with negative cultures were ultimately diagnosed with tuberculosis by measuring the adenosine deaminase levels. Mycobacteremia detection can be used to increase the sensitivity of the diagnosis of tuberculosis and other mycobacteria in patients with HIV. However, it cannot be used as the sole diagnostic method. Clinical specimen cultures do not provide 100% diagnostic accuracy and it is, therefore, critical to further improve the mycobacteria detection sensitivity.

Assessment of a novel scoring method based on solvent accessible surface area descriptors.

A novel scoring algorithm based on unique solvent accessible surface area (SASA) descriptors was comparatively evaluated for its database enrichment potential against the virtual screening (VS) methods GOLD and Glide. Several protein test cases, including adenosine deaminase and estrogen receptor alpha, were used for the evaluation. The structure-based VS method GOLD was used to generate the protein-ligand docking poses. These docking poses were then postprocessed with a protein-ligand interaction fingerprint metric. Next, the SASA descriptors were computed for each ligand and its respective protein in their bound/unbound states; a Bayesian model was learned with SASA descriptors and subsequently used to score the remaining ligands in the screening databases. Early database enrichments using SASA descriptors were found comparable or superior to those of GOLD and Glide. Moreover, SASA descriptors display an outstanding robustness to produce satisfactory early enrichments for a large variety of target classes. Based on these encouraging results, these novel topological descriptors constitute a valuable in silico tool in hit finding practices.

[Enzymes of purine nucleotide metabolism in assessment of the functional competence of the immune system].

Blood lymphocyte activities of 5'-nucleotidases, adenosine deaminase and AMP deaminase have been investigated for evaluation of immune system state of albino rats under normal conditions, immobilization stress and effect of radiation. Stress-induced reactions were characterized by changes of activities of these enzymes. However the ratios of activities 5'- nucleotidase/AMP-deaminase (coefficient A) and adenosine-deaminase/AMP-deaminase (coefficient B) were even more informative than separate analysis of these enzymes.

ADAR1 is involved in the development of microvascular lung injury.

Deamination of adenosine on pre-mRNA to inosine is a recently discovered process of posttranscription modification of pre-mRNA, termed A-to-I RNA editing, which results in the production of proteins not inherent in the genome. The present study aimed to identify a role for A-to-I RNA editing in the development of microvascular lung injury. To that end, the pulmonary expression and activity of the RNA editase ADAR1 were evaluated in a mouse model of endotoxin (15 mg/kg IP)-induced microvascular lung injury (n=5) as well as in cultured alveolar macrophages stimulated with endotoxin, live bacteria, or interferon. ADAR1 expression and activity were identified in sham lungs that were upregulated in lungs from endotoxin-treated mice (at 2 hours). Expression was localized to polymorphonuclear and monocytic cells. These events preceded the development of pulmonary edema and leukocyte accumulation in lung tissue and followed the local production of interferon-gamma, a known inducer of ADAR1 in other cell systems. ADAR1 was found to be upregulated in alveolar macrophages (MH-S cells) stimulated with endotoxin (1 to 100 microg/mL), live Escherichia coli (5x10(7) colony-forming units), or interferon-gamma (1000 U/mL). Taken together, these data suggest that ADAR1 may play a role in the pathogenesis of microvascular lung injury possibly through induction by interferon.

Exploratory analysis of population genetic assessment as a water quality indicator. II. Campostoma anomalum.

Biological monitoring programs to assess contaminant-induced impacts in aquatic systems are being developed and implemented by several federal agencies and many states. Genetic diversity and allozyme frequency may be valuable indicators of such impact because they are both sensitive to exposure and ecologically relevant in populations. The purpose of this study was to examine whether genetic diversity and structure of Campostoma anomalum populations could serve as effective biomarkers of exposure to anthropogenic stress by comparing genetic measures with other biological indicators of water quality. Fish were collected from 14 sites on seven streams by the Ohio Environmental Protection Agency as part of their stream water quality evaluation program. Values for the Index of Biological Integrity (IBI) and the Invertebrate Community Index (ICI) were determined for these 14 sites. Starch gel electrophoresis was used to collect genetic data for eight variable enzyme loci. Genetic diversity measures were not associated with site IBI or ICI values. However, the range of site IBI and ICI values was limited. Allele and genotype frequencies were significantly different at the point source compared to sites upstream and downstream indicating that genetic structure may be an indicator of water quality that is sensitive enough to detect change prior to species loss.