Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

---

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 interferon alfa (IFN-alpha) therapy on the expression of transforming growth factor alpha (TGF-alpha) in the liver during chronic hepatitis B was investigated. Serial liver biopsy specimens were evaluated from 35 patients who had participated in a randomized, controlled trial of recombinant human IFN-alpha for the treatment of chronic hepatitis B. Percutaneous liver biopsy specimens obtained before and 1 year after entry in the trial were sectioned and stained with a monoclonal antibody to TGF-alpha in an avidin-biotin-peroxidase-complex system. The expression of TGF-alpha in each section was evaluated blindly (with respect to treatment group and order of biopsies) and was numerically scored. There was no significant difference in TGF-alpha expression before or after therapy between 13 patients receiving daily IFN-alpha, 13 receiving alternate-day IFN-alpha, and 9 receiving no therapy. Sustained clearance of HBV-DNA and DNA polymerase activity occurred in 8 of 26 treated patients ("responders"); the 18 other patients were "nonresponders." Expression of TGF-alpha before IFN-alpha therapy was significantly higher in responders than in nonresponders; after IFN-alpha therapy, TGF-alpha expression decreased significantly among responders compared with nonresponders and untreated controls. Thus, the level of expression of TGF-alpha in the liver, which was correlated with the severity of inflammation in the liver in this study, appeared to be predictive of the response to IFN-alpha therapy in chronic hepatitis B, with a higher level of expression indicating a greater likelihood that the patient would respond.
...
PMID:Expression of transforming growth factor alpha in the liver before and after interferon alfa therapy for chronic hepatitis B. 755 46

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.
...
PMID:[Specific in situ labeling of apoptosis shows different rates of programmed cell death in non-Hodgkin lymphomas]. 788 32

A new method for typing single nucleotide polymorphisms in DNA is described. In this method, specific fragments of genomic DNA containing the polymorphic site(s) are first amplified by the polymerase chain reaction (PCR) using one regular and one phosphorothioate-modified primer. The double-stranded PCR product is rendered single-stranded by treatment with the enzyme T7 gene 6 exonuclease, and captured onto individual wells of a 96 well polystyrene plate by hybridization to an immobilized oligonucleotide primer. This primer is designed to hybridize to the single-stranded target DNA immediately adjacent from the polymorphic site of interest. Using the Klenow fragment of E. coli DNA polymerase I or the modified T7 DNA polymerase (Sequenase), the 3' end of the capture oligonucleotide is extended by one base using a mixture of one biotin-labeled, one fluorescein-labeled, and two unlabeled dideoxynucleoside triphosphates. Antibody conjugates of alkaline phosphatase and horseradish peroxidase are then used to determine the nature of the extended base in an ELISA format. This paper describes biochemical features of this method in detail. A semi-automated version of the method, which we call Genetic Bit Analysis (GBA), is being used on a large scale for the parentage verification of thoroughbred horses using a predetermined set of 26 diallelic polymorphisms in the equine genome.
...
PMID:Genetic Bit Analysis: a solid phase method for typing single nucleotide polymorphisms. 793 43

We have developed and evaluated an ELISA-based detection method for PCR-amplified HIV-1 DNA. The assay uses two oligonucleotide probes which are end-labelled at the 5'-end with biotin or digoxigenin, respectively. Upon solution hybridization of these probes which react with the same strand of amplified DNA product, the formed hybrids are bound to avidin-coated wells of a microtitre plate and detected by horseradish peroxidase-labelled antibodies directed against digoxigen and 3, 3', 5, 5'-tetramethylbenzidine as substrate. Factors critical for a high signal-to-noise ratio were the use of serum as blocking agent, the amount of biotin-labelled and digoxigenin-labelled oligonucleotide probes present in a reaction and the inactivation of Taq DNA polymerase. The method has a detection limit of 1-3 pg of amplified DNA and is quantitative in a range extending from 1 pg to at least 200 pg. In the background of 1 microgram of total DNA, one single-stranded copy of HIV-1 DNA can be detected after 35 cycles of amplification. A comparison of the ELISA-based detection method with primer extension analysis, a method previously shown to reach a similar detection limit, demonstrated complete agreement of the results of 118 amplified DNAs. The method proved simple, requires only about 3 h, and could easily be adapted to the detection of other amplified target DNAs.
...
PMID:Sensitive and quantitative detection of PCR-amplified HIV-1 DNA products by an enzyme linked immunoassay following solution hybridization with two differently labelled oligonucleotide probes. 826 70

Proliferative activity of 28 human brain tumors was estimated by simultaneous measurement of DNA polymerase alpha, Ki-67 and bromodeoxyuridine (BUdR) labeling indices on microscopic tissue preparations stained immunologically with monoclonal antibodies using a peroxidase technique. All the antigens were exclusively found in the nucleus. The labeling index of BUdR was lower than those of the other indicators. The values of the DNA polymerase alpha labeling index were almost the same as those of the Ki-67 labeling index. Simultaneous measurement of these parameters may provide more useful information on tumor cell growth kinetics than that of a single parameter.
...
PMID:Measurement of labeling index of DNA polymerase alpha in human brain tumors. Comparative study with labeling indices of BUdR in vitro and Ki-67. 832 65

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.
...
PMID:Rapid bright-field detection of oligonucleotide primed in situ (PRINS)-labeled DNA in chromosome preparations and frozen tissue sections. 882 52

Terminal deoxynucleotidyl transferase (TdT) is a DNA polymerase located in the cell nucleus which catalyses the polymerization of deoxynucleotides at the 3'hydroxyl ends of oligo- or polydeoxynucleotide initiators without a template. TdT is known as a useful marker for the diagnosis of acute lymphoblastic leukaemia/lymphoma, but its detection usually requires fresh tissue specimens or cell suspensions, using either an enzyme analysis or immuno-fluorescence or -peroxidase staining. Until the recent development of the use of microwave-treated paraffin sections for immunoperoxidase staining, detection of TdT in paraffin sections required rather complicated processes. This new simple technique was applied to paraffin sections from the tumour tissue specimens of 16 patients with lymphoblastic lymphoma and of seven patients with non-endemic Burkitt's lymphoma, which is sometimes difficult to differentiate from lymphoblastic lymphoma because of their similar clinicopathological characteristics. In addition, as a control, ten cases each were examined of adult T-cell leukaemia/lymphoma (ATLL) and angioimmunoblastic lymphoma (AILD), which are both peripheral T-cell lymphomas. The tumour cells from 15 of the 16 (94 per cent) patients with lymphoblastic lymphoma were found to be TdT-positive. The specificity of the anti-TdT antibody used was confirmed by immunoblot and the specific 60 kD band was detected only in a specimen of lymphoblastic lymphoma. These results show that the immunostaining of TdT on paraffin-embedded sections is a useful method for differentiating lymphoblastic lymphoma from other lymphomas. This method is applicable to a routine diagnostic service.
...
PMID:Terminal deoxynucleotidyl transferase staining of malignant lymphomas in paraffin sections: a useful method for the diagnosis of lymphoblastic lymphoma. 922 46

To test the hypothesis that mitochondrial DNA (mtDNA) is more prone to reactive oxygen species (ROS) damage than nuclear DNA, a continuous flux of hydrogen peroxide (H2O2) was produced with the glucose/glucose oxidase system. Using a horse radish peroxidase (HRPO)-based colorimetric assay to detect H2O2, glucose oxidase (GO; 12 mU/ml) produced 95 microM of H2O2 in 1 h, whereas only 46 microM of hydrogen peroxide accumulated in the presence of SV40-transformed human fibroblasts ( approximately 1 x 10(6). DNA damage was assessed in the mitochondira and three nuclear regions using a quantitative PCR assay. GO (12 mU/ml) resulted in more damage to the mitochondrial DNA (2.250 +/- 0.045 lesions/10 kb) than in any one of three nuclear targets, which included the non-expressed beta-globin locus (0.436 +/- 0.029 lesions/10 kb); and the active DNA polymerase b gene (0.442 +/- 0.037 lesions/10 kb); and the active hprt gene (0.310 +/- 0.025). Damage to the mtDNA occurred within 15 min of GO treatment, whereas nuclear damage did not appear until after 30 min, and reached a maximum after 60 min. Repair of mitochondrial damage after a 15 min GO (6 mU/ml) treatment was examined. Mitochondria repaired 50% of the damage after 1 h, and by 6 h all the damage was repaired. Higher doses of GO-generated H202, or more extended treatment periods, lead to mitochondrial DNA damage which was not repaired. Mitochondrial function was monitored using the MTT (3,(4,5-dimethylthiazol-2-yl)2,5-diphenyltetrazolium bromide) assay. A 15 min treatment with 6 mU/ml of GO decreased mitochondrial activity to 80% of the control; the activity recovered completely within 1 h after damage. These data show that GO-generated H202 causes acute damage to mtDNA and function, and demonstrate that this organelle is an important site for the cellular toxicity of ROS.
...
PMID:Preferential mitochondrial DNA injury caused by glucose oxidase as a steady generator of hydrogen peroxide in human fibroblasts. 944 35

In order to test the hypothesis that Epstein-Barr virus (EBV) may be a cofactor for oral squamous cell carcinoma (OSCC) the authors evaluated tumour cells from OSCC of 108 patients without HIV infection, for the presence of EBV DNA by polymerase chain reaction. The sequences of oligonucleotides used in the amplification and hybridization included a set for the DNA polymerase region. The amplification was detected using an ELISA assay with peroxidase. EBV DNA was detected in 17.59% of the tumours. Inhibition studies showed that the ability to detect EBV DNA was not affected by the pathological material, suggesting that the negative PCR results in these samples were not caused by PCR inhibitors in the biopsy. Results revealed that 63.1% of the tumours (12 cases) were DNA positive affecting the lateral margin of the tongue, and were statistically significant (p < 0.001; chi 2). In the pool of tumours with EBV DNA only 26.3% (5 of 19 cases) were well differentiated OSCCs whereas the remaining 73.7% (14 of 19 cases) were moderately and poorly differentiated OSCCs, with a statistical significance of p = 0.08; chi 2. This study suggests a relationship between OSCC and EBV.
...
PMID:Epstein-Barr virus and oral squamous cell carcinoma in patients without HIV infection: viral detection by polymerase chain reaction. 1034 99

In situ hybridization (ISH) is a powerful and important technique that allows the detection and microscopic localization of nucleic acids within the specific cell, tissue, or chromosome of interest. In addition, it offers increased sensitivity over traditional filter hybridization, since low-copy mRNA molecules in individual cells can be detected. At the time the ISH technique was developed by Pardue and Gall (1), there were restrictions in it since radioisotopes were the only labels for nucleic acids available and autoradiographic film was the only detection system. Current molecular biological cloning techniques have now enabled most researchers to prepare almost any specific probe of choice and, more importantly, modern nonradioactive labels with colorimetric detection have removed all the limitations and restrictions of radioactive labels. The principal advantages of nonradioactive hybridization compared with isotopic hybridization are increased speed, greater resolution, lower costs, and reduced radioactive exposure. Furthermore, it allows the opportunity for combining different labels in one ISH experiment. The procedures behind ISH localization of DNA or RNA are very similar and may be summarized in five areas: (1) sample and glass slide preparation, including fixation, mounting, and ISH pretreatment, (2) probe preparation/labeling, (3) hybridization, (4) probe removal/washing, and (5) detection. Nonradioactive probe labeling itself can be divided into two methods, i.e., direct and indirect. This chapter describes the preparation of atherosclerotic tissue for ISH, indirect labeling of probes with digoxigenin (DIG), and the detection protocols suitable for this type of tissue. The DIG labeling method was developed by Kessler (2) and is based on the steroid digoxigenin, which is isolated from Digitalis purpurea and D. lanata. The DIG molecule is linked to the C-5 position of uridine (UTP, dUTP, or ddUTP) via a spacer arm. The DIG-labeled nucleotides can be incorporated easily into nucleic acid probes by DNA polymerases such as DNA polymerase I,Taq DNA polymerase, T7 DNA polymerase, RNA polymerases, and terminal transferase. These various enzymes therefore allow DIG labeling by random priming, nick translation, PCR, 3'-end labeling/tailing, and in vitro transcription. Following hybridization, DIG-probes may be detected with high-affinity specific anti-DIG antibodies (3). These antibodies are conjugated with alkaline phosphatase, peroxidase, fluoroscein, rhodamine, AMCA (amino-methylcoumarin-acetic acid), or colloidal gold (for electron microscopy) enabling a very versatile detection system. This system can be made even more versatile and sensitive by using unconjugated anti-DIG followed by conjugated secondary antibodies. A detection sensitivity of about 0.1 pg (as determined by Southern blot) can be achieved with combinations of anti-DIG-alkaline phospatase and NBT or BCIP. In this chapter, I describe a protocol that we developed for nonradioactive in situ hybridization of atherosclerotic tissue for the detection of interleukin 8, tissue factor, and tissue factor pathway inhibitor in both frozen and paraffin-embedded tissue (4-7).
...
PMID:1Nonradioactive In Situ Hybridization in Atherosclerotic Tissue. 2134 Sep 43


<< Previous 1 2 3 Next >>

---