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)

To determine whether natural human interferon administered under the usual therapeutic dosing scheme would inhibit the hepatic drug metabolism, we performed an antipyrine test in eight patients with chronic B or non-A, non-B hepatitis before and after a subchronic interferon therapy (6 megaunits/day for 17 +/- 4 days, mean +/- SD). Six patients received interferon-beta and 2 received interferon-alpha. To circumvent a possible influence of interferon-induced fever on the hepatic drug metabolism, the antipyrine test during the interferon therapy was performed at least 14 days after the interferon-induced fever disappeared. The kinetic parameters of antipyrine were obtained from seven saliva samples over 32 hours postdose. There were no significant differences in any kinetic parameters of antipyrine observed before and during the interferon therapy. With the sample size of the study, there was only a 20% chance (i.e., beta-power = 0.8 at alpha = 0.05) that we might have missed a 17% reduction in antipyrine clearance by the interferon therapy (type II error). On the other hand, the subchronic interferon therapy lowered serum aminotransferases and DNA polymerase activity significantly (P less than .05) compared with the respective baseline values. Our results suggest that the subchronic therapeutic dosing scheme of interferon as conducted in the present study does not cause the inhibitory effect on the oxidative drug metabolism to a statistically significant or clinically relevant degree in patients with chronic hepatitis, while it improves their liver function. Further studies are required for determining if different types of interferons administered under the different dosing schemes would alter the hepatic drug metabolism and the inhibitory effect would be time-dependent.
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PMID:Effects of subchronic treatment with natural human interferons on antipyrine clearance and liver function in patients with chronic hepatitis. 211 64

Two years or more after 35 patients (29 men and six women) with chronic hepatitis B were treated by interferon, we studied relationships of age, ALT activity, activity of serum DNA polymerase associated with the hepatitis B virus, serum levels of hepatitis B e antigen and activity of 2',5'-oligoadenylate synthetase in peripheral blood mononuclear cells when treatment started in comparison with treatment results. Seventeen patients were given human lymphoblastoid interferon-alpha; the other 18 patients were given interferon-beta. We measured the activity of 2',5'-oligoadenylate synthetase in these mononuclear cells and found the rate of increase in vivo and in vitro; the correlation between the two was r = 0.68. This enzyme activity in the patients who became negative for DNA polymerase after interferon treatment increased more both in vivo and in vitro than in patients who did not became negative. Also, both the in vivo and in vitro activity increased more in patients who became negative for the e antigen after interferon therapy than in those who remained positive. In the first group, interferon was considered to be effective; in the second, ineffective. Of the patients who became negative, some developed e antibodies and some did not; the increase in this enzyme activity in the two groups was not significantly different. The increase in the activity of 2',5'-oligoadenylate synthetase activity could be used to predict the results of interferon treatment and is an index that can be used before treatment to predict the response.
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PMID:Relationship of the effects of interferon on chronic hepatitis B and the induction of 2',5'-oligoadenylate synthetase. 247 40

Twenty patients with HBe antigen positive, chronic active hepatitis receiving interferon-beta (HuIFN-beta) for 4 weeks were studied. Within the follow-up period (12.3 +/- 2.0 months; mean +/- SD), nine patients were seroconverted to anti-HBe positive and/or HBe antigen negative. In vitro synthesis of interleukin-1 (IL-1), interleukin-2 (IL-2) and interferon-gamma (IFN-gamma) were determined from supernatants of peripheral blood mononuclear cells (PBMCs) cultured in the presence of lipopolysaccharide or concanavalin-A. PBMCs from patients before IFN-beta treatment secreted markedly reduced levels of IL-1 (p less than 0.01) and IFN-gamma (p less than 0.01) as compared with healthy controls. However, IFN-gamma synthesis in the patients was significantly increased (p less than 0.05) along with the IFN-beta treatment. IL-2 synthesis was similar in chronic active hepatitis B patients before and during IFN-beta treatment when compared to normal controls, but after the therapy, the elevation of IL-2 synthesis was observed in accordance with the elevation of serum AST in two cases. Nine patients who seroconverted to anti-HBe positive and/or HBe antigen negative showed the significantly lower levels of DNA polymerase before IFN-beta treatment than non-responder group. There were no other differences in sex, age, serum AST, histologic activities and cytokine production in vitro between two groups. These results indicate the presence of immunologic deficiencies in patients with HBe antigen positive chronic active hepatitis and give the rationales for the use of interferon treatment on immunologic basis.
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PMID:[In vitro cytokine production in patients with HBe antigen positive chronic active hepatitis receiving interferon-beta]. 250 83

A new type of plasmid expression vector was developed for direct expression of foreign genes in Escherichia coli. The plasmid vector, designated pTrS3, carries the E. coli tryptophan (trp) promoter and the Shine-Dalgarno (SD) sequence for the trp leader peptide as well as an ATG sequence located 13 bp downstream from the SD sequence. The dG residue of this ATG overlaps with the first dG residue of the single Sph I recognition sequence (GCATGC) of the vector DNA. After cleaving pTrS3 DNA by Sph I, the 3' protruding Sph I ends were converted into blunt ends using the Klenow fragment of E. coli DNA polymerase I. Subsequently, the DNA fragments coding for mature human interferon-beta or for the interferon lacking several aminoterminal amino acids, were ligated to this vector DNA and cloned in E. coli. Interferon activity was detected in the extracts of bacterial strains harboring the recombinant plasmids and the results indicated that the interferon-beta polypeptides without the five aminoterminal amino acids might be less active than the mature form.
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PMID:Construction and application of a novel plasmid "ATG vector" for direct expression of foreign genes in Escherichia coli. 631 98

Ribavirin is a nucleoside analog that inhibits the replication of many DNA and RNA viruses. To evaluate the efficacy of oral ribavirin, we randomly assigned 24 HBeAg-positive patients with chronic active hepatitis to a 12-wk course of treatment with 0.8 to 1.0 gm/ribavirin day, 3 mU interferon-beta three times a week intravenously or a combination of those drugs. Ribavirin, alone and in combination with interferon-beta, decreased hepatitis B virus levels in most patients, and mean serum hepatitis B virus DNA and DNA polymerase levels at the end of treatment were approximately half of baseline levels (p < 0.05). Interferon alone exerted the most inhibitory effect on hepatitis B virus activity (p < 0.01). During ribavirin treatment, changes in serum aminotransferase values varied considerably and the mean values did not change significantly, although interferon alone and the combination of interferon and ribavirin were associated with significant reductions in serum aminotransferase activities. Ribavirin was well tolerated, but we transiently reduced the dosage in two cases because of mild hemolytic anemia, although all patients completed the treatment schedule. The combination of interferon and ribavirin did not appear to result in greater toxicity. During the follow-up period (6 to 9 mo), HBeAg and hepatitis B virus DNA disappeared in one patient treated with ribavirin, in two treated with interferon and in two given the combination. These results indicate that ribavirin suppresses hepatitis B virus replication, although its effect is less than that of interferon, and that it may be useful as adjunctive therapy for chronic hepatitis B.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Pilot study of ribavirin and interferon-beta for chronic hepatitis B. 834 55