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

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Query: EC:2.7.7.7 (DNA polymerase)
17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To study the antiproliferative response of B cells to interferon-alpha (IFN-alpha) at the molecular level, we developed a cell-free system to assess DNA synthesis in nuclei isolated from IFN-sensitive Daudi B lymphoblastoid cells. [3H]dTTP incorporation in isolated nuclei was shown to be representative of replicative DNA synthesis by evidence that (i) incorporation was dependent on ATP and all four nucleoside precursors, (ii) incorporation was inhibited greater than 97% by aphidicolin, a specific inhibitor of DNA polymerase alpha and delta, and (iii) the DNase I-sensitive product banded in neutral CsCl at a density indicative of replicative DNA. This cell-free model was used in conjunction with flow cytometric cell cycle analysis to determine the effect of IFN-alpha on DNA synthesis in Daudi cells. The addition of IFN-alpha to an IFN-growth sensitive Daudi subclone in G0/early G1 inhibited the initiation of DNA synthesis, assessed in isolated nuclei, and prevented the progression of cells into S phase. IFN-alpha failed to inhibit DNA synthesis or cell cycle progression when added to IFN-sensitive Daudi cells in late G1/early S phase or to an IFN-resistant Daudi subclone. These studies suggest that IFN-alpha inhibits DNA replication and cellular proliferation in Daudi B cells by interfering with G1 cell cycle events.
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PMID:DNA synthesis in nuclei isolated from Daudi B cells: a model to study the antiproliferative mechanisms of interferon-alpha. 157 80

The biological significance of antibody reactivities towards the preS2 gene encoded proteins of HBV is not yet well known. We investigated the pretreatment IgM anti-preS2 (1-55) ad reactivity in 22 Chinese and 11 Swedish patients with active HBV disease. Significantly enhanced IgM anti-preS2 levels (titers greater than 1/1000) were observed in 48% (16/33) of these patients. The OD405 values for sera from patients with indolent HBsAg carriership were within the range of that obtained for "normal" control-sera when tested at dilutions from 1/1000 to 1/128,000. Five Chinese patients were treated with a short course of corticosteroids, followed by alpha-interferon 2b (IFN-alpha 2b) treatment for 16 weeks. The IgM anti-preS2 response was consecutively monitored during treatment. A beneficial effect on the outcome of the combined treatment was associated with rising titers of IgM anti-preS2 during the prednisolone cycle. The IgM anti-preS2 levels fell dramatically upon steroid withdrawal and were followed by a second peak response of IgM anti-preS2 reactivity during the IFN-alpha 2b treatment. No sustained loss of HBV-DNA or DNA polymerase with concomitant HBe/anti-HBe seroconversion was observed in treated patients, who lacked detectable pretreatment levels of IgM anti-preS2 in circulation.
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PMID:IgM anti-preS2 monitoring during combined corticosteroid/interferon-alpha 2b therapy in chronic hepatitis B. 177 15

A pilot study was designed to determine the tolerance and effectiveness of natural or recombinant gamma interferon in patients with chronic hepatitis B. Sixteen patients received 0.5 to 3.0 million units (MU) per day of gamma interferon (IFN-gamma) for 7 days. Nineteen chronic hepatitis B patients who were treated with 5-6 MU leukocyte-derived alpha interferon (IFN-alpha) daily served as controls. All completed the treatment schedule. IFN-gamma exerted mild, but significant inhibitory effects (P less than .05) on serum DNA polymerase levels. However, the changes were significantly less (P less than .001) than those seen with IFN-alpha therapy when compared with percent change from basal values. In contrast, serum 2', 5'-oligoadenylate synthetase (2-5 AS) activities were markedly enhanced to a similar extent during therapy with both IFNs. Serum beta 2-microglobulin values were significantly increased by administration with both IFNs, although higher values were seen with IFN-gamma. Five patients received 1 MU IFN-gamma for 28 consecutive days and their HBeAg levels similarly decreased as those seen in patients treated with IFN-alpha. Side effects seemed to be greater during IFN-gamma therapy than IFN-alpha despite the lower doses used. The antiviral effect on serum HBV levels appeared less with IFN-gamma than with IFN-alpha. Alternatively immunomodulatory functions may have been enhanced with IFN-gamma in patients with chronic HBV infection.
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PMID:Treatment with human gamma interferon of chronic hepatitis B: comparative study with alpha interferon. 194 Aug 81

We analyzed the binding of 125I-labelled IFN-alpha to peripheral blood mononuclear cells in 19 healthy controls, 25 asymptomatic HBV carriers (AsC), and 69 patients with HBs antigen positive chronic liver disease (CLD). Histological examination showed that of the 69 patients with CLD, 14 had chronic persistent hepatitis (CPH), 46 had chronic active hepatitis (CAH), 9 had liver cirrhosis (LC). The mean number of IFN-alpha/beta receptor sites per cell totaled 1270 +/- 340 in the healthy controls, 1440 +/- 290 in AsC, and 1600 +/- 480 in CLD (with 1770 +/- 480 in CPH, 1580 +/- 490 in CAH, and 1420 +/- 410 in LC). HBV carriers had more IFN-alpha/beta receptor sites than the healthy controls (AsC: P less than 0.1, CLD: P less than 0.01). In CLD, patients with LC tended to have fewer IFN-alpha/beta receptor sites than those with CPH or CAH. The number of IFN-alpha/beta receptor sites in CLD was correlated with the HBe antigen titer (P less than 0.01), and activity of HBV-DNA polymerase (P less than 0.05). These results were suggested that IFN-alpha/beta receptor sites was higher at the HBV carrier state, and correlated with viral replication.
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PMID:[Interferon-alpha/beta receptors in patients with chronic HBV infection]. 214 66

Twenty-six patients, positive for hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), hepatitis B virus (HBV)-deoxyribonucleic acid (DNA), and DNA polymerase activity, were treated with human lymphoblastoid interferon (IFN-alpha) or human fibroblast interferon (IFN-beta) after enoxolone glycoside (glycyrrhizinic acid), given for four weeks and then withdrawn. The interferons were given continuously for four weeks. Four months after the treatment, six of 12 patients treated with IFN-alpha were both HBeAg-negative and HBV-DNA-negative while three of 14 patients treated with IFN-beta were HBV-DNA-negative and one was HBeAg-negative. None of the ten untreated control patients became negative for either HBeAg or HBV-DNA. All patients studied remained HBsAg-positive. Both interferons were generally well tolerated. A persistent low-grade fever was reported by more patients in the IFN-beta group and hair and weight loss were more common in the IFN-alpha group. The results indicate that the combination of enoxolone glycoside withdrawal and IFN-alpha treatment reduces HBV replication more effectively than does interferon alone.
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PMID:Human lymphoblastoid and fibroblast interferon in the treatment of chronic hepatitis B. 232 24

Thirty-five patients with active chronic hepatitis B (ACH-B) were evaluated. They were in stable replicative phase (HBeAg +; DNA polymerase and ALT stable in two determinations at least one month apart) and had not been infected by delta virus or HIV-1. Thirty-four patients were heterosexual and no patient was a drug abuser except one. The 23 initial cases were followed up for 15 months without therapy. The subsequent 12 cases were treated with maximal doses of 2.5 megaunits/m2 of lymphoblastoid alpha interferon (IFN-L) daily for two weeks and three times a week during 10 more weeks. While in the controls only two cases (8.69%) lost the DNA-polymerase activity and HBeAg, 5 treated patients (41.66%; p less than 0.05) developed seroconversion to nonreplicative phase. No patient from the control series lost the HBsAg; however, this happened in 2 treated patients (16.66%). These results show that IFN-L is effective in heterosexual patients with ACH-B in replicative phase without delta virus or HIV-I co-infection.
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PMID:[Treatment of chronic hepatitis B with lymphoblastoid alpha interferon]. 261 34

24 Chinese children aged 1.5-5 years and positive for hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), hepatitis B virus DNA polymerase (HBV DNAp), and HBV DNA on at least three occasions in the 6 months before the trial were randomised to receive either vitamin B complex or intramuscular recombinant alpha 2-interferon (r-IFN) ('Roferon') 10 X 10(6) IU/m2 thrice weekly for 12 weeks. In all 12 subjects receiving r-IFN, HBV DNAp and HBV DNA levels fell during the course of r-IFN injections. Within 4 weeks of cessation of r-IFN injection, the HBV DNAp and HBV DNA returned to pre-trial levels except in 2 subjects, in whom loss of HBV DNAp and HBV DNA was sustained for up to 18 months from onset of the trial. 1 child lost HBeAg at 18 months. 2 of the 12 children in the placebo group also had a sustained loss of HBV DNAp and HBV DNA during the 18 months, with 1 child losing HBeAg at 18 months. All 24 subjects remained positive for HBsAg. r-IFN produced very slight side-effects except for pyrexia and the "flu" syndrome, both of which showed rapid tachyphylaxis. In the dose given r-IFN was safe but had no long-term beneficial effects on HBsAg carriage in Chinese children.
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PMID:Placebo-controlled trial of recombinant alpha 2-interferon in Chinese HBsAg-carrier children. 288 81

Escherichia coli-derived human interferon-gamma (rIFN-gamma) inhibited the replication of human cytomegalovirus (HCMV) synergistically when combined with IFN-alpha. The induction of HCMV DNA polymerase was inhibited in rIFN-gamma-treated cells. It is suggested that the induction of 2-5 A synthetase does not play an important role in the anti-HCMV actions of IFNs.
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PMID:Effect of recombinant human interferon gamma against human cytomegalovirus. 303 15

Bovine interferon-alpha I1 (IFN-alpha I1) and porcine interferon-gamma (IFN-gamma) inhibited African swine fever virus replication in both porcine monocytes and alveolar macrophages. The most potent antiviral activity was observed with IFN-gamma-treated alveolar macrophages. The production of both a virulent (CC83) and a non-virulent (BA71) isolate of the virus was inhibited. Bovine tumour necrosis factor alpha did not show antiviral activity in either monocytes or alveolar macrophages. Rather, an increase of African swine fever virus production in tumour necrosis factor alpha-treated monocytes was found. An analysis of viral protein synthesis in IFN-alpha I1- and IFN-gamma-treated alveolar macrophages showed an inhibition of synthesis of some viral proteins. The inhibition of late proteins was very pronounced in IFN-gamma-treated cells, and it was probably a consequence of the inhibition of African swine fever virus DNA polymerase activity.
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PMID:Effect of interferon-alpha, interferon-gamma and tumour necrosis factor on African swine fever virus replication in porcine monocytes and macrophages. 314 9

A total of 24 chronic carriers of HBsAg, HBeAg and hepatitis B virus (HBV)-DNA were included in a controlled trial. The patients were randomly assigned to four groups: Group I (n = 6): control; group II (n = 6): 2.5 MU; group III (n = 6): 5 MU and group IV (n = 6): 10 MU rIFN-alpha/m2 body surface 3 times weekly i.m. during 6 months. At the end of the treatment, all patients under therapy, as well as 4 belonging to the control group, lost HBV-DNA polymerase. HBV-DNA became negative in 3 (50%), 1 (17%), and 2 (33%) patients from groups II, III, and IV, respectively, while all patients from the control group maintained HBV-DNA. At 15 months of follow-up, 6 patients (33%) under therapy (2 from each group) and 1 from the control group remained HBV-DNA-negative. Knodell's index decreased significantly on comparing basal and final liver biopsies among patients in group IV (16.0 +/- 1.9 vs 7.0 +/- 1.9, p less than 0.01), while no changes were observed in the other groups. Five patients (27%) developed anti-IFN antibodies during treatment. In summary, although low doses of rIFN-alpha (2.5-5 MU) had an antiviral effect on HBV replication, only patients treated with 10 MU showed a significant decrease in liver histological activities. In addition, the effectiveness of rIFN-alpha therapy may be negatively influenced by the appearance of anti-IFN antibodies.
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PMID:Different doses of recombinant alpha interferon in the treatment of chronic hepatitis B patients without antibodies against the human immunodeficiency virus. 321 26


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