Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.7 (DNA polymerase)
 17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of zinc on the growth of a transplantable DAB hepatoma in young male Wistar rats was determined. Both a zinc deficiency (less than 0.5 microgram/g feed) as well as high levels of dietary zinc (500 micrograms/g feed) significantly reduced tumor growth. Both high- and low-zinc diets resulted in reduced activity of the salvage pathway of thymidine synthesis as well as reduced 32PO4 incorporation into DNA and diminished DNA polymerase activity. Blockage of the de novo pathway of DNA synthesis by the folate antagonist methotrexate (MTX) resulted in greatly increased flux through the thymidine salvage pathway and increased DNA polymerase activity but decreased 32PO4 incorporation in the transplantable hepatomas in Wistar rats fed normal zinc diets (50 micrograms/g feed). MTX had the effect of reducing all these activities in the groups fed low- and high-zinc diets. These data suggested a site of action of zinc associated with the salvage pathway of thymidine synthesis.
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PMID:Possible site of zinc control of hepatoma cell division in Wistar rats. 657 40

Two new techniques were used to quantify cell death (i.e. DNA fragmentation) in situ: (1) 3' overhangs of the fragmented DNA were end labelled with biotin-7-dATP and TdT (peroxidase/DAB). (2) In situ nick translation (ISNT) was performed with DNA polymerase 1 and biotin-7-dATP, to label single strand segments of DNA (peroxidase/DAB). Both methods were tested to be negative in ischemic and tumor necrosis, and negative for mitotic figures. In 26 centroblastic Non Hodgkin lymphomas (CB) (monomorphous subtype [n = 9], polymorphous subtype [n = 7], secondary [n = 10]), 14 chronic lymphocytic leukemias and two immunocytomas these methods were employed to quantify the rate of cell death. ISNT proved to be more sensitive than end labelling. By ISNT, CB had a mean cell death rate of 250/10HPF (monomorphous type: 429/10HPF, polymorphous type: 222/10HPF, secondary: 111/10HPF). CLL showed a significantly lower rate (28/10HPF). These data suggest, that the low rate of cell turnover in CLL is indicated by a low rate of cell proliferation and a low rate of programmed cell death. In CB the high proliferation rate was accompanied by a high level of cell death. In CB/monomorphous a high turnover state with a very high proliferation and cell death rate was found, whereas CB/polymorphous represents an expansive state as indicated by a lower rate of cell death. CB/secondary showed almost no programmed cell death and therefore was interpreted as a high expansive state neoplasia.
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PMID:[Specific in situ labeling of apoptosis shows different rates of programmed cell death in non-Hodgkin lymphomas]. 788 32

We describe a new application of a bright-field microscopic procedure for rapid enzyme cytochemical detection of repeated DNA sequences in metaphase preparations and frozen tissue sections. Various chromosome-specific oligonucleotide primers were used in up to three sequential primed in situ (PRINS) labeling reactions together with Taq DNA polymerase and biotin, digoxigenin and/or fluorescein isothiocyanate (FITC)-modified nucleotides. DNA target sequences were localized simultaneously by the precipitates of the horseradish peroxidase-diaminobenzidine (PO-DAB, brown color), alkaline phosphatase-Fast Red (APase-Fast Red, red color) and horseradish peroxidase-teramethylbenzidine (PO-TMB, green color) reaction in hematoxylin counterstained metaphases and interphase nuclei using a standard bright-field microscope. In addition, a protocol is reported for the application of PRINS to frozen tissue sections from normal colon and bladder epithelium. Methanol/acetic acid fixation in combination with a pepsin digestion before performing the PRINS reaction proved to be critical steps in the total procedure that permits access of the PRINS reactants, while preserving the morphology of the nuclei in the tissue. Quantification of PRINS signals showed the majority of epithelial cells with the expected two chromosome copies. The described procedures can be considered valuable tools for application in molecular cytogenetics, cell biology and pathology.
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PMID:Rapid bright-field detection of oligonucleotide primed in situ (PRINS)-labeled DNA in chromosome preparations and frozen tissue sections. 882 52