Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Ca, Mg-dependent endonuclease is one of the main DNAses of lymphocyte chromatin. It's activity is known to increase in the immune response and to decrease in spontaneous and experimental CLL. These observations became a basis for analysis of possible clinical meaning of it's enzymatic activity assay. Donors' peripheral blood lymphocytes being tested, normal level of endonucleolysis for men and children was defined. Except that patients with different clinical forms of lymphoproliferative diseases such as chronic lympholeukemia, non-Hodgkin lymphomas, Hodgkin's disease were observed. The results showed that Ca, Mg-dependent endonucleolysis activity was decreased in comparison to donors' one. Ca, Mg-dependent endonucleolysis activity was the same in the group of patients with non-malignant pathology and in donors' one. Successful treatment and remission state of our patients was associated with alteration of the Ca, Mg-dependent endonucleolysis activity to normal level as well as immunological parameters. That is why the activity of Ca, Mg-dependent endonucleolysis is suggested to be a new criterion of immune state and lymphocyte malignant transformation.
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PMID:[Changes in Ca, Mg-dependent endonuclease of DNA in isolated nuclei of human lymphocytes in lymphoproliferative diseases]. 239 89

Peripheral blood mononuclear cells from five patients with IgG+ B-type chronic lymphocytic leukemia (B-CLL) were analyzed for the presence of clone-specific Ig H chain variable region gene mRNA transcripts linked to C mu and/or C alpha. This was assessed by (1) comparing the lengths of portions of the VHDJH of the IgG+ CLL clones with those of the mu and alpha isotype-expressing B cells, (2) performing clone-specific endonuclease digestion studies, and (3) determining the DNA sequences of the mu and alpha isotype-expressing cDNA. Thus, when B-cell mRNA from these five patients were reverse transcribed with C gamma-specific primers and then amplified by polymerase chain reaction, dominant cDNA were found with lengths corresponding to those of the IgG+ CLL B cell. In addition, in four cases, cDNA of lengths identical to those of the CLL B cell were detected when mRNA was reverse transcribed and amplified using c mu- and/or C alpha-specific primers, strongly suggesting clonal relatedness. These CLL-related mu- and alpha-expressing cDNA were present in greater amounts that unrelated (non-CLL) mu- and alpha-expressing cDNA from normal B cells that used genes of the same VH family. When the sequences of these CLL-related C mu- and C alpha-expressing cDNA were compared with those of the IgG+ CLL clones, it was clear that they were derived from the same ancestral gene as the IgG-expressing CLL B cell, thus documenting their common origin. Finally, nucleotide point mutations were observed in the mu- and alpha-expressing cDNA of certain patients, indicating divergence with the CLL. These data suggest that IgM+ B cells, which are precursors of the leukemic B cells, exist in increased numbers in the blood of most patients with IgG+ B-CELL and that these cells may differentiate, accumulate V genes mutations, and undergo isotype switching in vivo. In addition, the data are consistent with a sequential-hit model for the evolution of CLL.
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PMID:Evidence for progenitors of chronic lymphocytic leukemia B cells that undergo intraclonal differentiation and diversification. 860 51

A case of CLL with two different cellular populations is reported. A 50-year-old man was evaluated for persistent absolute lymphocytosis. A peripheral blood smear revealed numerous small lymphocytes (83% of white blood cells counted). Frequent Grumpecht shadows were present, too. On bone marrow aspirate smears lymphocytes comprised 85% of the total cells counted, and the bone marrow biopsy showed a mixed nodular-interstitial infiltration pattern. The immunophenotypic study showed two different leukemic populations. The first one (comprising 79% leukemic cells) was CD5+, CD19+, CD10-, CD20+, CD18-, CD22-, CD23+ +, lambda dim, and FMC7-. The second population (comprising 21% leukemic cells) was CD5+, CD19+, CD10-, CD20+, CD18+, CD22+, CD23+, lambda+ +, and FMC7+. Gene rearrangement studies detected the germline and one rearranged band in Jk blot with each restriction endonuclease. In the Jh blot the germline and two rearranged bands were detected with EcoRI and BamHI and three rearranged bands with HindIII. The JBI/JBII blot detected only the germline band. The detection of three rearranged bands was interpreted as evidence of the presence of at least two monoclonal populations of cells with the same light chain restriction.
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PMID:Chronic lymphocytic leukemia with two cellular populations: a biphenotypic or biclonal disease. 920 Sep 98

Two flow cytometric apoptosis assays, the terminal deoxynucleotidyl transferase (TdT) assay and in situ nick translation (ISNT) assay, were assessed for their ability to quantitate drug-induced apoptosis in CLL lymphocytes. In contrast to HL60 cells, biotinylated dUTP could not be effectively incorporated into apoptotic CLL lymphocytes using exogenous TdT. This suggested that CLL lymphocytes possess a different type of endonuclease that cleaves DNA, leaving blunt or 3' recessed DNA breaks, which are poor substrates for TdT. This possibility was tested using lambda exonuclease, which can convert a blunt or 3' recessed DNA break into a 3' overhang. Apoptotic CLL lymphocytes pre-treated with lambda exonuclease demonstrated increased nucleotide incorporation with TdT. Single-strand DNA breaks are also present in apoptotic CLL lymphocytes, as labelled nucleotides could be incorporated using the in situ nick translation assay. This study suggests that the efficiency of tailing reactions may be limited by the nature of the endonuclease activity in certain cell types and that validation with other parameters is an essential prerequisite to their quantitative use.
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PMID:Flow cytometric apoptosis assays indicate different types of endonuclease activity in haematopoietic cells and suggest a cautionary approach to their quantitative use. 948 82