Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied the effects of adenosine and adenosine derivatives on adenylate cyclase activity in cultured endothelial cells from bovine pulmonary artery. Basal and stimulated enzyme activities were measured in membrane preparations using [alpha-32P]ATP as the substrate and chromatographic isolation of formed [32P]cAMP. Basal cyclase activity was 11 +/- 1 (mean +/- SEM) pmol/mg protein/min. Forskolin, 5'-guanylylimidodiphosphate (Gpp(NH)p) and (-)isoproterenol stimulated adenylate cyclase in a concentration-dependent manner, producing maximal stimulations of three, seven and four times the basal activity respectively. In the presence of adenosine deaminase, cyclohexyladenosine, an A1 agonist, had no effect on basal and forskolin- or Gpp(NH)p-stimulated activities, whereas 5'-(N-ethyl)-carboxamidoadenosine (NECA), an A2 agonist, had a small stimulatory effect (52% increase over basal). In the presence of IBMX, adenosine and two P-site agonists, 2',5'-dideoxyadenosine (DDA) and 2'-deoxyadenosine-3'-monophosphate (2'-deoxy-3'-AMP), inhibited forskolin (30 microM)-stimulated adenylate cyclase activity with an order of potency of 2'-deoxy-3'-AMP greater than DDA greater than adenosine. DDA and 2'-deoxy-3'-AMP were also able to inhibit cyclase activity stimulated by Gpp(NH)p (10(-5)M) or isoproterenol (10(-6)M) with the same order of potency. Only 2'-deoxy-3'-AMP inhibited the stimulated adenylate cyclase activity by more than 50% (IC50 = 19-32 microM). These findings indicate that (1) long-term cultured endothelial cells from bovine pulmonary artery express A2 and beta-adrenergic receptors which stimulate adenylate cyclase activity through Gs transducer proteins, and (2) the natural compound and P-site agonist, 2'-deoxy-3'-AMP, is a potent inhibitor, and possibly a natural regulator, of adenylate cyclase activity in this tissue.
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PMID:Modulation of adenylate cyclase activity in cultured bovine pulmonary arterial endothelial cells. Effects of adenosine and derivatives. 246 5

The effect of the irreversible S-adenosyl-L-homocysteine hydrolase inhibitor, (Z)-5'-fluoro-4',5'-didehydro-5'-deoxyadenosine (MDL 28,842), on C-1300 murine neuroblastoma (MNB) cell proliferation in tissue culture and MNB tumor growth in vivo were investigated. MNB cells were incubated with MDL 28,842 at concentrations ranging from 8 x 10(-9) M to 1.6 x 10(-5) M for 3 days, and cell proliferation was determined by use of a CellTiter 96-well Proliferation Assay Kit. In tissue culture, MDL 28,842 inhibited MNB cell proliferation in a concentration-dependent manner, and the IC50 of MDL 28,842 against MNB in tissue culture was 1.8 x 10(-7) M. The response of in vivo tumor growth and host survival to MDL 28,842d was evaluated in a syngeneic mouse tumor model prepared by s.c. implantation of 1 x 10(6) MNB cells into A/J mice. Following palpation of a tumor mass, osmotic minipumps were implanted into each mouse. MDL 28,842 was infused at rates of 1.0 or 1.5 mg/kg/day over a 10-day period and 1.25 mg/kg/day over a 30-day period. The mean survival time of tumor-bearing mice significantly increased from 28.75 +/- 1.06 days (mean +/- 2 SEM) in the control group (diluent infusion) to 39.33 +/- 1.58 days, 44.11 +/- 1.74 days, and 41.0 +/- 1.30 days in the MDL 28,842-treated groups receiving 10-day infusions of 1.0 and 1.5 mg/kg/day or 30-day infusions of 1.25 mg/kg/day, respectively. No significant differences in survival rate were noted between groups receiving 10 vs 30 days of drug treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Suppression of C-1300 murine neuroblastoma cell proliferation in tissue culture and tumor growth in vivo by (Z)5'-fluoro-4',5'-didehydro-5'-deoxyadenosine (MDL 28,842), an irreversible inhibitor of S-adenosyl-L-homocysteine hydrolase. 805 4

1,N6-etheno-2'-deoxyadenosine (epsilondA) is one of several promutagenic DNA modifications arising from cellular oxidative metabolism. It is believed that these background DNA lesions may contribute to various diseases, such as cancer. Therefore, human biomonitoring of epsilondA in urine could be a potential marker for oxidative stress-related DNA damage. Existing methods for quantifying urinary epsilondA use 32P postlabeling. We have developed a nonradioactive, fast, and easier method based on column-switching liquid chromatography with atmospheric pressure chemical ionization tandem mass spectrometry (LC/APCI-MS/MS) in the positive mode. Differences in column temperatures were used to influence analyte retention and sample focusing. With multiple reaction monitoring (MRM) mode the afforded limit of detection was about 0.7 pM when starting with 3 ml of urine. The urinary excretion rates of epsilondA from 28 nonsmoking and 5 smoking men were 10.0-99.6 pmol/24 h, and did not correlate with body weight, age, or plasma vitamin C concentration. The 5 smokers excreted 30.5 +/-8.5 and the 28 nonsmokers excreted 38.6 +/- 2.4 pmol epsilondA per 24 h, p=.37 (mean +/- SEM). The demonstrated level of performance suggests the future applicability of this method to studies of cancer and other diseases related to oxidative stress in humans.
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PMID:Quantification of 1,N6-etheno-2'-deoxyadenosine in human urine by column-switching LC/APCI-MS/MS. 1513 74