Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023418 (leukemia)
 93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

cCMP-specific phosphodiesterase activity was demonstrated in the 80 to 100% ammonium sulfate fraction obtained from disrupted leukemia L-1210 cells. The activity was linear with time (up to 60 min), was a function of protein concentration, and was markedly stimulated by Mg2+ and by ammonium sulfate. Under identical assay conditions, no significant hydrolysis of cAMP or cGMP was observed, although these cyclic nucleotides served as substrates for phosphodiesterase(s) present in all the fractions obtained by less than 80% ammonium sulfate saturation. This is the first demonstration of a cCMP-specific phosphodiesterase.
 ...
PMID:Demonstration, in leukemia L-1210 cells, of a phosphodiesterase acting on 3':5'-cyclic CMP but not on 3':5'-cyclic AMP or 3':5'-cyclic GMP. 20 54

Cyclic nucleotide phosphodiesterase activities were examined in lymphocytes from 12 transformed human B cell lines, two T cell lines, six patients with lymphocytic leukemia, and 10 normal donors. A consistent difference bwtween cells from the normal and leukemic state was observed. The cyclic AMP phosphodiesterase activity from normal lymphocytes is inhibited greater than 80% by muM cyclic GMP while this concentration of nucleotide has little or no effect on the enzyme from transformed lymphocytic cell lines or from lymphocytic cells of leukemia patients. The reported lack of cyclic GMP phosphodiesterase in human lymphocytes from several sources is confirmed. The apparent absence of a cyclic GMP degradation mechanism and of cyclic GMP control of cyclic AMP hydrolysis may be related to defective lymphocyte growth control.
 ...
PMID:Cyclic AMP phosphodiesterase in human lymphocytes and lymphoblasts. 20 51

In the present study transfer factor (TF) failed to produce any change in the cAMP- and cGMP-levels of lymphocytes of patients with chronic lymphoid leukaemia (CLL). This is attributed to the malignant transformation of the lymphocytes or to a changed proportion of different lymphocyte populations in CLL. Human TF leaves the cyclic nucleotide levels of splenic lymphocytes of BALB/c mice unaffected.
 ...
PMID:In vitro effect of transfer factor on the cyclic nucleotide level of human lymphocytes in chronic lymphocytic leukaemia and of mouse lymphocytes. 21 15

Constant intracellular concentrations of both adenosine 3',5'-cyclic-monophosphate (cyclic AMP) and guanosine 3',5'-cyclic-monophosphate (cyclic GMP) were obtained when leukemia L1210 cells were cultivated under steady-state conditions in the chemostat. In this sensitive and controlled system addition of mouse interferon resulted in a rapid (5-10 min) increase in the intracellular concentration of cyclic GMP, which preceded by several hours an increase in the intracellular concentration of cyclic AMP. In contrast to the effect of interferon, addition of prostaglandin E1 induced a rapid increase in the intracellular concentration of cyclic AMP without markedly affecting the intracellular concentration of cyclic GMP. It is suggested that the rapid effect of interferon on cyclic GMP plays a role in mediating some of the effects of interferon on cells.
 ...
PMID:Effect of interferon on concentrations of cyclic nucleotides in cultured cells. 22 87

The effects of several cytokines and phorbol myristate acetate (PMA) on LFA-1 and ICAM-1 expression on a human eosinophilic leukemia cell line, EoL-3, were investigated and compared with those of a human monocytic leukemia cell line, U937. EoL-3 cells expressed large amounts of LFA-1 and small amounts of ICAM-1, and their expression was regulated similarly in EoL-3 cells and U937 cells. Interferon-gamma (IFN-gamma) enhanced ICAM-1 expression but not LFA-1 expression, and PMA augmented both LFA-1 and ICAM-1 expression. IFN-gamma and PMA showed an additive effect on ICAM-1 expression. These results collectively suggest that expression of LFA-1 and ICAM-1 is regulated differently and that IFN-gamma and PMA regulate the expression through different mechanisms. PMA but not IFN-gamma induced homotypic adhesion of EoL-3 and U937 cells, suggesting that PMA but not IFN-gamma activated the adhesive function of these cells. Staurosporin, an inhibitor of protein kinases (PKs), partly suppressed IFN-gamma- and PMA-augmented expression of ICAM-1 on EoL-3 and U937 cells, but did not affect PMA-augmented LFA-1 expression, suggesting that staurosporin-sensitive PKs are involved in IFN-gamma- and PMA-augmented ICAM-1 expression but not in PMA-augmented LFA-1 expression. The role of protein kinase C (PK-C) in these mechanisms was not revealed because a PK-C inhibitor, H-7, did not show any definitive effect on IFN-gamma- and PMA-induced expression of LFA-1 and ICAM-1. Moreover, cyclic AMP (cAMP)- and cGMP-dependent pathways were not shown to be involved in the augmentation of the expression of these molecules.
 ...
PMID:Regulation of the expression of leukocyte function-associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) on a human eosinophilic leukemia cell line EoL-3. 135 14

To verify the clinical usefulness of extracellular cyclic nucleotide determinations as tumour markers in preneoplastic syndromes, plasma cyclic AMP (cAMP) and cyclic GMP (cGMP) levels were monitored in 47 patients with refractory anaemia with excess of blasts (35 RAEB and 12 RAEBt), 20 of whom progressed to acute leukaemia during the observation period. The control group consisted of 45 healthy subjects matched for age and sex. In all groups of patients plasma cAMP levels were within the normal range, whereas plasma cGMP levels were significantly higher than those of normal subjects in both RAEB and RAEBt patients, and increased further when progression to acute leukaemia occurred. These data suggest that serial determinations of plasma cGMP may be useful to monitor the progression of the disease, though there is no evidence that cGMP values at diagnosis may have a prognostic significance.
 ...
PMID:Plasma cyclic nucleotide levels in patients with refractory anaemia with excess of blasts. 215 84

The synthetic nucleoside tiazofurin(2-beta-ribofuranosylthiazole-4-carboxyamide) and its selenium analog selenazofurin inhibited the growth of L1210 leukemia cell culture in a dose dependent manner with IC50 value of 2.0 and 0.2 Um respectively. The GTP/ATP ratio was diminished 4-6 fold as measured by HPLC, while IMP/ATP increased 6-8 fold. The decreased guanylate pools may explain the 30% reduction in cyclic GMP levels and GTPase activity measured after the treatment with the nucleosides. Inhibition of phospholipase C activity is suggested since diacylglycerol content, protein kinase C activity and phorbol ester binding of the membrane fraction were also reduced 20-40%. These results reveal a novel aspect in the action of these compounds which may play a role in their therapeutic action and selectivity.
 ...
PMID:Tiazofurin and selenazofurin induce depression of cGMP and phosphatidylinositol pathway in L1210 leukemia cells. 255 3

Heat-inactivated rabbit antiserum, in the absence of complement, induced a 1.5-2-fold increase in cyclic AMP levels in target cells L5178Y leukemia lymphoblasts within 10-20 min after the experiment. This change preceded the previously reported delayed inhibitory effects of antiserum on cell growth such as inhibition of RNA, DNA, and protein synthesis and cell proliferation, suggesting that cyclic AMP may be one of the mediators of the antigen-antibody reactions which occur at the cell surface. Furthermore, the addition of cyclic GMP or excess calcium to either antiserum or cyclic AMP-treated cultures alleviated the growth inhibitory effects of either antiserum or cyclic AMP, substantiating further the hypothesis proposed.
 ...
PMID:Role of cyclic AMP in antiserum-induced growth inhibition of murine leukemia L5178Y cells. 258 12

Cyclic guanosine 3',5'-monophosphate (cGMP) concentrations were measured in urine specimens from guinea pigs before and after transplantation of a leukemia. A transient increase in cGMP concentration occurred 3 days after inoculation which preceded any detectable increase in the white blood cell count. This peak in cGMP concentration was found to be very highly significant when compared with fluctuations in urinary cGMP levels in the guinea pigs from transplantation of the leukemia. Inoculation of guinea pigs with irradiated L2C cells suggests that transplantation may cause an initial depression in urine cGMP concentration but no elevated cGMP concentrations were observed in these animals. The results indicate that urine cGMP concentrations may be a useful way of monitoring abnormal cell proliferation.
 ...
PMID:Alterations in concentrations of cyclic guanosine 3',5'-monophosphate in guinea pig urine during the development of a transplantable leukaemia. 299 65

Normal human neutrophilic granulocytes and granulocytes of chronic myelogenous leukaemia (CML) were shown to possess only the "high Km type" isoenzyme of cAMP-phosphodiesterase. The properties of this enzyme are similar in both normal and CML granulocytes. cGMP-phosphodiesterase in human granulocytes was found to be composed of "high Km type" and "low Km type" isoenzymes. The high Km cGMP-phosphodiesterase of CML granulocytes showed a considerably lower apparent Km and Vm value than those in normal neutrophilic granulocytes.
 ...
PMID:Cyclic 3':5'-adenosine monophosphate phosphodiesterase and cyclic 3':5'-guanosine monophosphate phosphodiesterase of normal granulocytes and granulocytes of chronic myelogenous leukaemia. 302 16


1 2 3 4 Next >>