Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.5.4.17 (adenosine deaminase)
 5,206 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We evaluated the ability of three enzymes--N-acetyl-beta-D-glucosaminidase (NAG; EC 3.2.1.30), alanine aminopeptidase (AAP; microsomal aminopeptidase, EC 3.4.11.2), and gamma-glutamyltransferase (GGT; EC 2.3.2.2)--and adenosine deaminase binding protein (ABP) in urine to predict or confirm renal-transplant rejection in patients treated with cyclosporine. We measured the enzymes daily during the early post-transplant hospital stay of 104 renal-transplant recipients (72 men and 32 women). We also measured ABP in 32 of these patients. We analyzed the data by calculating the activity ratio of each day's test value to the previous day's result and optimized the sensitivity (SN) and specificity (SP) to determine the optimal ratio for each test. The results indicate that cyclosporine treatment reduces the optimal sensitivity and specificity of these tests. Three comparable tests (ABP, GGT, and AAP) yield the best optimal values (SN = 0.77, 0.69, 0.77; and SP = 0.71, 0.74, 0.63, respectively), and the NAG test yields the lowest combination of sensitivity and specificity (SN = 0.62, SP = 0.66). All four tests were less sensitive and specific than the plasma creatinine test (optimal day-to-day difference = 5 mg/L). However, the ABP and AAP tests gave indications of rejection at least 24 h before clinical diagnosis for 50% of the patients experiencing rejection, while early plasma creatinine increases of 5 mg/L occurred in only 19% of this group.
 ...
PMID:Indicators of acute renal-transplant rejection in patients treated with cyclosporine. 233 86

As a part of our efforts to design prodrugs for antiviral nucleosides, 9-(beta-D-arabinofuranosyl)-6-azidopurine (6-AAP) was synthesized as a prodrug for ara-A that utilizes the azide reduction biotransformation pathway. 6-AAP was synthesized from ara-A via its 6-chloro analogue 4. The bioconversion of the prodrug was investigated in vitro and in vivo, and the pharmacokinetic parameters were determined. For in vitro studies, 6-AAP was incubated in mouse serum and liver and brain homogenates. The half-lives of 6-AAP in serum and liver and brain homogenates were 3.73, 4.90, and 7.29 h, respectively. 6-AAP was metabolized primarily in the liver homogenate microsomal fraction by the reduction of the azido moiety to the amine, yielding ara-A. However, 6-AAP was found to be stable to adenosine deaminase in a separate in vitro study. The in vivo metabolism and disposition of ara-A and 6-AAP were conducted in mice. When 6-AAP was administered by either oral or intravenous route,the half-life of ara-A was 7-14 times higher than for ara-A administered intravenously. Ara-A could not be found in the brain after the intravenous administration of ara-A. However, after 6-AAP administration (by either oral or intravenous route), significant levels of ara-A were found in the brain. The results of this study demonstrate that 6-AAP is converted to ara-A, potentially increasing the half-life and the brain delivery of ara-A. Further studies to utilize the azide reduction approach on other clinically useful agents containing an amino group are in progress in our laboratories.
 ...
PMID:Synthesis, biotransformation, and pharmacokinetic studies of 9-(beta-D-arabinofuranosyl)-6-azidopurine: a prodrug for ara-A designed to utilize the azide reduction pathway. 897 48