Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019163 (hepatitis B)
 38,309 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The 5'-flanking sequence of the human prothrombin gene was isolated by screening a human liver phage library with a human prothrombin cDNA as a hybridization probe. A phage was identified that contained 3 kilobase pairs of DNA upstream of the initiator methionine codon. Primer extension studies showed that the major transcription initiation sites were located 23 and 36 base pairs upstream of the initiator codon. DNA sequences in the 5'-flanking region of the human prothrombin gene were then analyzed for cis-activating transcriptional activity by a transient expression system using the human growth hormone gene as the reporter gene. The chimeric expression vector was introduced into HepG2 cells, and secreted human growth hormone was monitored by using a radio-immunoassay. These studies showed that the 3-kilo-base pair fragment contained sequences that were sufficient for the initiation of transcription in HepG2 cells. Subsequent deletion studies showed that the 3-kilobase pair fragment contained two elements: a weak promoter in the region immediately upstream of the mRNA coding sequence and an enhancer located between nucleotides -860 and -940. The enhancer element was active at a distance and in either orientation. In addition, the enhancer was liver cell-specific and acted on heterologous promoters including the herpes simplex virus thymidine kinase promoter and the mouse metallothionein I promoter. Comparison of the nucleotide sequence of the enhancer with a DNA sequence data base showed the enhancer sequence to be unique. The enhancer sequence is flanked by an inverted repeat 5' CCTCCC 3' and contains a putative binding site for hepatic nuclear factor 1. Deoxyribonuclease I footprint analysis and linker scanning mutagenesis showed that the enhancer contains multiple protein binding motifs. Mutagenesis of the 3' boundary CCTCCC sequence eliminated the enhancer activity. Comparison with other liver genes showed the presence of the CCTCCC sequence in the hepatitis B virus enhancer, the alpha 1-antitrypsin promoter, and the fibrinogen beta-chain promoter, suggesting a functional role for this motif.
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PMID:Characterization of a novel liver-specific enhancer in the human prothrombin gene. 191 8

Presented are the steps in creating a recombinant DNA molecule, examples of recombinant drug products, a description of DNA fingerprinting methods for diagnosing diseases, a discussion of the patenting of recombinant drugs, and a look to the future of this revolutionary biotechnology. Constructing a recombinant DNA molecule involves cutting the DNA into fragments with restriction endonucleases and rejoining the fragments in novel arrangements with ligase. Propagating the molecule in a microorganism, or cloning, is necessary to increase the number of gene copies to facilitate detection of the gene of interest and to produce the protein it encodes. Recombinant DNA drug products have been developed that represent the communicator, structural, and modifier classes of proteins. Recombinant communicator proteins include interferons alfa-2a and alfa-2b and granulocyte-macrophage colony-stimulating factor (immune system modulators); epidermal growth factor and erythropoietin (tissue repair promoters); and human insulin, growth hormone, and atrial peptide (metabolism modulators). Recombinant structural proteins include hepatitis B virus vaccine and CD4 protein, and recombinant modifier proteins include tissue plasminogen activator and superoxide dismutase (agents that split or splice organic molecules). In the future, gene defects associated with genetic diseases will be unraveled, leading to the production of new therapeutic agents designed to counteract or actually reverse those defects. Recombinant protein drugs will be further tailored to enhance their activity and specificity. These advances are so novel and momentous that patent protection has been extended not only to recombinant drugs but to the recombinant microorganisms in which they are manufactured. In cloning genes, investigators directly use the protein designs that occur naturally. Basic research will soon lead to the engineering of novel proteins with specified functions.
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PMID:Drug products of recombinant DNA technology. 267 63

Brain biopsy is justified in patients suspected of having encephalitis or viral encephalopathy because those patients are most likely to be helped if a diagnosis is made rapidly and with the greatest certainty possible. Neurosurgeons are occasionally reluctant to undertake brain biopsy because the procedure is diagnostic rather than therapeutic in intent. However, using currently available techniques a 1 cm3 sample of brain tissue can be taken with very low risk of morbidity or mortality. We recommend that the sample be taken from the anterior portion of the inferior temporal gyrus on the more affected side in patients with herpes simplex encephalitis, and from an area of maximum demonstrated involvement in other situations, using stereotactic techniques and intraoperative ultrasound as necessary. The risk to the operating surgeon and to the other members of the operating team appears very low in all of the situations discussed in this chapter. However, the authors feel that every patient should be approached as if he carries the hepatitis B virus. As indicated, the incidence of contracting hepatitis B after sustaining needle stick exposure to blood from persons positive for hepatitis B surface antigen is 10-15%. Conjunctival contamination by splash from the wound is a known method of inoculation of surgeons with hepatitis B virus and is a possible means for transmission of other viral diseases. We recommend that every patient be approached as if he has hepatitis B, not because the agent diseases discussed are known to be as infectious as hepatitis B, but because constant vigilance and careful technique offer the best protection to the surgeon and the members of the operating team in most situations, and because one can never be certain what agent diseases a given patient may harbor. With the exception of the Creutzfeldt-Jakob virus, the agents responsible for all of the viral diseases discussed are inactivated by standard procedures for sterilization of operating room instruments. Procedures necessary to inactivate the Creutzfeldt-Jakob disease virus have been presented. In the report documenting transmission of Creutzfeldt-Jakob disease through human growth hormone preparations the authors state, "We are once again dramatically reminded that human tissues are a source of infectious disease, and that any therapeutic transfer of tissue from one person to another carries an unavoidable risk of transferring the infection.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Brain biopsy for encephalitis. 353 42

A method of introducing actively expressed genes into intact mammals is described. DNA precipitated with calcium phosphate has been injected intraperitoneally into newborn rats. The injected genes have been taken up and expressed by the animal tissues. To examine the generality of the method we have injected newborn rats with the chloramphenicol acetyltransferase prokaryotic gene fused with various viral and cellular gene promoters and the gene for hepatitis B surface antigen, and we observed appearance of chloramphenicol acetyltransferase activity and hepatitis B surface antigen in liver and spleen. In addition, administration of genes coding for hormones (insulin or growth hormone) resulted in their expression.
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PMID:Direct introduction of genes into rats and expression of the genes. 354 Sep 43

Gene/biotechnology products can be either physiological peptides for the purpose of substitution of deficiencies or for therapeutic purposes in superphysiological concentrations, or nonphysiological peptides, or newer biotechnology products like monoclonal antibodies. The rules for clinical trials developed so far are also valid for clinical trials with gene/biotechnology products. Nevertheless, a major challenge for the clinical pharmacologist is the species specificity of many reactions induced by gene/biotechnology products in man. In general, animal experiments may be less predictive, so there is a greater demand for human pharmacology studies. Gene/biotechnology products offer more chances for treatment of many diseases, but during the clinical trials the clinician has to always be aware of unexpected side effects. Several newer gene technology products offer superior safety as compared to older biological products like Factor VIII preparations and human growth hormone. More than 19 therapeutics produced by gene/biotechnology have already been approved by health authorities all over the world. Major clinical benefit could be shown with hepatitis B vaccine, insulin, human growth hormone, TPA, erythropoietin, GM-CSF, G-CSF, and monoclonal antibodies for immune suppression. There is also good evidence of efficacy of interferon alpha in chronic hepatitis. So far, our knowledge about cytokines is still limited. In several cancer diseases, interferons show efficacy as well as in several autoimmune diseases. Well designed clinical pharmacology studies will be important to elaborate the therapeutic potential of drugs arising from gene/biotechnology.
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PMID:Clinical trials of gene/biotechnology products. 788 81

During the course of woodchuck hepatitis virus (WHV) replication three virus-specific mRNA transcripts that encode four essential proteins are produced. The transcripts are 3.6, 2.3, and 0.7 kb in size. The 3.6-kb transcript serves as the replicative intermediate as well as the template for translation of the nucleocapsid and polymerase proteins. The 2.3-kb mRNA serves as the template for translation of the virus envelope proteins. Both the 3.6- and 2.3-kb transcripts are polyadenylated and are readily found in the cytoplasm of infected hepatocytes. However, the 0.7-kb transcript, specific for the X gene, accumulates in the nucleus of infected cells and is polyadenylated poorly in hepatocytes. Thus, while it is likely that the 0.7-kb transcript is the template for translation of the X protein, it is possible that it also has a function at the RNA level to regulate virus replication or gene expression. In order to characterize the WHV X promoter we cloned the region of the WHV8 genome encompassing the viral enhancer through the amino terminus of the X gene into the vector pSV0CAT. We transfected Huh-7 and WLC-3 cells with the WHV X promoter construct, along with a plasmid encoding human growth hormone to control for transfection efficiency, and assayed for the presence of chloramphenicol acetyl transferase activity. We found that the WHV X promoter was about one-half as active as the well-studied simian virus 40 early or Rous sarcoma virus promoters. Next, we made a series of 5' and 3' deletion mutants and mapped the WHV X promoter to a 21-nucleotide domain (1482-GGGGAAGCTGACGTCCTTTCC-1502) which is approximately 100 bp downstream of the corresponding promoter in hepatitis B virus. Further analysis, using oligonucleotide-directed mutagenesis, demonstrated that the essential nucleotides comprising the WHV X promoter are located in a 10-nucleotide domain near the initiation codon of the X gene. Mutation of either nucleotide T at position 1490 or G at position 1491 within this domain was sufficient to reduce the level of promoter activity by 100-fold. Thus, we have defined the important nucleotides within the promoter of the WHV X transcript which is a first step in understanding the role of this transcript in WHV replication and gene expression.
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PMID:Analysis of the X gene promoter of woodchuck hepatitis virus. 797 27

A plasmid carrying a DNA fragment of hepatitis B virus, coding for the pre-S2 and the entire S region of the surface antigen (HBsAg), placed under the control of the promoter of the human 70 kDa heat shock protein gene (hsp70), was introduced into Line 6, a recombinant cell line that was selected from NIH-3T3 cells previously transfected with a similar construct coding for the human growth hormone cDNA gene (chGH) and with the plasmid pEJ carrying the Ha-rasEJ activated cellular oncogene. The resulting cell line, EMS8, expressed: (1) hsp70/HBsAg and hsp70/hGH hybrid genes, (2) the human Ha-rasEJ oncogene, and (3) the neomycin resistance gene, the two last plasmid markers being used for cell selection. EMS8 cells were able to carry out post-translational modifications of the middle M and the major S envelope proteins of HBV, such as assembly and glycosylation. Accordingly, the cells synthesized and secreted both free and glycosylated M and S viral proteins, and the human growth hormone protein. In addition concomitant expression of HBsAg and hGH proteins as well as their mRNA were detected in EMS8 cells at least up to 72 hr after heat induction instead of 24 hr in the case of hGH in Line 6 cells.
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PMID:Concomitant cellular expression of heat shock regulated genes of hepatitis B virus surface antigen and of human growth hormone by a NIH-3T3 cell line. 803 9

We present data demonstrating that hydrogen peroxide markedly decreases release of progeny hepatitis B virus particles in cultured cells. The presence of reduced glutathione prevents this effect. Hydrogen peroxide also decreases secretion of the hepatitis B virus surface and e antigens, with a concomitant decrease in the steady-state levels of the corresponding viral transcripts. This effect is specific to viral gene expression, since hydrogen peroxide at the concentration used does not have any significant effect on the overall pattern of host cell protein synthesis nor on the secretion of growth hormone from a co-transfected plasmid. Since hepatitis B virus can cause acute and chronic hepatitis and since inflammatory cells release significant amounts of reactive oxygen species, including hydrogen peroxide, this phenomenon may be of pathophysiological importance in the viral life cycle.
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PMID:Negative regulation of hepatitis B virus gene expression and replication by oxidative stress. 813 21

Hepatitis B viruses (hepadnaviruses) can cause chronic, productive infections of hepatocytes. Analyses of the enhancers and promoters of these viruses in cell lines have suggested a requirement of these elements for liver-enriched transcription factors. In this study, a minimum of seven factor-binding sites on the duck hepatitis B virus enhancer were detected by DNase I footprinting using duck liver nuclear extracts. Among the sites that were tentatively identified were one C/EBP-, one HNF1-, and two HNF3-binding sites. Mutations of the HNF1- and HNF3-like sites, which eliminated factor binding, as assessed by both DNase I footprinting and competitive gel shift assays, were evaluated for their effects on enhancer activity. Using a construct in which human growth hormone was expressed from the viral enhancer and core gene promoter, we found that all of the mutations, either alone or in combination, reduced expression two- to fourfold in LMH chicken hepatoma cells. The mutations in the HNF1 site and one of the HNF3 sites, when inserted into the intact viral genome, also suppressed virus RNA synthesis in primary hepatocyte cultures. Virus carrying the latter HNF3 mutation was also examined for its ability to infect and replicate in ducks. No significant inhibition of virus replication was observed in a short-term assay; however, virus with the HNF3 mutation was apparently unable to grow in the pancreas, a second site of duck hepatitis B virus replication in the duck.
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PMID:Identification of factor-binding sites in the duck hepatitis B virus enhancer and in vivo effects of enhancer mutations. 813 13

High serum concentrations of growth hormone (GH) were found in five patients with chronic liver diseases, including auto-immune chronic active hepatitis (two cases), Budd-Chiari syndrome, primary biliary cirrhosis and hepatitis B virus associated cirrhosis. Mean levels of GH were 27.8 units (normal up to 5). In three patients elevated prolactin levels were also found (mean 37.3 units for two females, normal up to 20), and 36 units in one male (normal up to 9). No other endocrine disorders were found. Although the association of raised GH levels in patients with alcoholic cirrhosis is well known, its occurrence in patients with non-alcoholic chronic liver disease is not fully established. We describe the effect of the disease course, and steroid treatment on GH levels in one patient with auto-immune chronic active hepatitis, and propose possible mechanisms for this elevation.
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PMID:Elevated growth hormone levels in patients with non-alcoholic chronic liver disease. 821 92


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