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 core of Dane particles, the presently accepted hepatitis B virus nucleocapsid, contains two polypeptides (P19 and P45) with the antigenicity of hepatitis B e antigen (HBeAg). The antigenicity of hepatitis B core antigen (HBcAg) was not detectable in either of them by the conventional in vitro assay methods, despite the fact that both of these polypeptides were derived from the core of Dane particles. When a rabbit had been immunized with the purified preparation of P19 emulsified in complete Freund's adjuvant, however, humoral antibody against HBcAg was produced in addition to the antibody against HBeAg. Amino acid analysis of P19 disclosed a high content of arginine (12.9%), leucine (11.9%), serine (10.3%) and proline (10.2%). The amino acid composition of P19 was found to be strikingly similar to the composition of the 183 amino acid sequence deduced from the sequence of hepatitis B virus DNA which has been presumed to be encoding HBcAg. We conclude that both HBeAg and HBcAg are antigenic determinants borne by the major polypeptide (P19) constituting the core of Dane particles.
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PMID:Demonstration of the immunogenicity of hepatitis B core antigen in a hepatitis B e antigen polypeptide (P19). 617 55

Classic hemophilia or factor VIII deficiency is a recessive, sex-linked bleeding diathesis. The primary clinical problem is hemorrhage, which can be severe and often life threatening, even in the presence of only minor trauma. In the past this inadequate hemostasis has been treated with transfusions of cryoprecipitate, fresh frozen plasma, or commercially prepared factor VIII concentrate. Unfortunately, such treatment carries with it a number of risks, including the development of hepatitis B or hemolytic anemia and the formation of anti-factor VIII antibodies. Because of hemorrhage severity and the risks of conventional treatment, elective surgery in general and oral surgery in particular have often been neglected in patients with hemophilia. This article reviews a drug, 1-desamino-8-d-arginine (DDAVP), heretofore not discussed in the dental literature, and reports on its use in conjunction with epsilon-aminocaproic acid (EACA), a synthetic antifibrinolytic agent, in the surgical dental treatment of a patient with hemophilia A. The results suggest that certain dental surgical procedures can be performed in the presence of subclinical and mild hemophilia without conventional factor VIII replacement therapy with its associated costs and risks.
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PMID:DDAVP: review of indications for its use in the treatment of factor VIII deficiency and report of a case. 622 10

Since the immunosorbent techniques and the cycles of isopycnic and rate zonal velocity ultracentrifugations were shown to be unsuitable for the purification of hepatitis B surface antigen (HBsAg) particles from human sera because HBsAg was still largely contaminated by serum proteins, we applied a drastic dissociating treatment of HBsAg stabilized by adsorption on silica gel which appeared essential to remove extraneous components initially present in the HBsAg particles. Only albumin and sometimes IgG were recovered with the purified antigen. The polypeptide composition of our purified HBsAg preparations was analyzed by SDS-PAGE with subsequent transfer to a nitrocellulose sheet by blotting, incubation with 125I-anti-HBs and exposure to X-ray film. Samples from HBsAg-positive sera containing the hepatitis B virus e antigen (HBeAg) displayed three proteins: P 24.5 and GP 28 as major components and GP 36 as a minor component. Dimers of these polypeptides were also immunologically detected. When a supplementary step of trypsin or pepsin digestion was included in our purification procedure after adsorption to silica and acid dissociation of HBsAg, proteolytic cleavage fragments of HBsAg with mol. wts lower than 10,000 were obtained on SDS-PAGE after reduction. This finding shows that arginine and lysine residues inaccessible to tryptic digestion in the intact HBsAg lipoprotein particle were exposed to enzymatic hydrolysis by our treatment. However, HBsAg kept the antigenic and immunogenic properties of the native antigen. Therefore such a HBsAg preparation appeared as a new candidate for the vaccination against HBV and a useful material for the analysis of the HBs antigenic structure.
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PMID:Immunochemical structure of the hepatitis B surface antigen vaccine--I. Treatment of immobilized HBsAg by dissociation agents with or without enzymatic digestion and identification of polypeptides by protein blotting. 642 72

The mechanism of N alpha-cocoyl-L-arginine ethyl ester (CAE) in the inactivation of hepatitis B surface antigen (HBsAg) was investigated. The CAE increased the density of HBsAg, and particles of the antigen were destroyed in amorphous clusters, suggesting that CAE influences the lipid components of HBsAg. The lipid components such as cholesterol and phospholipid were mostly removed from the antigen by the treatment with CAE. N alpha-Lauroyl-L-[U-14C] arginine ethyl ester (LAE), a principal component of CAE, became tightly bound to HBsAg in place of the lipid components. The binding amounts of LAE in the HBsAg-LAE complex reached 3.04 +/- 0.44 microgram/mg of protein. The formation of the complex was not influenced by the presence of CAE-related compounds such as L-arginine, L-arginine ethyl ester, and N alpha-cocoyl-L-arginine. Treatment with mercaptoethanolurea, guanidine hydrochloride, and some detergents failed to resolve appreciably the labeled LAE from the labeled complex. All attempts to reactivate the CAE-treated HBsAg and to restore it morphologically from the denatured aggregates were unsuccessful. These results indicate that CAE tightly binds to HBsAg, followed by formation of stable aggregates of the denatured HBsAg-CAE complex.
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PMID:Mechanism of inactivation of hepatitis B surface antigen by N alpha-cocoyl-L-arginine ethyl ester. 728 11

We have reported previously that N alpha-cocoyl-L-arginine ethyl ester (CAE) strongly inactivates hepatitis B surface antigen (HBsAg; Sugimoto and Toyoshima, Antimicrob. Agents Chemother. 16:329--332, 1979). Replacement of the L-arginine moiety of CAE by L-lysine did not decrease the HBsAg-inactivating effect of CAE, whereas replacement by some neutral amino acids and L-ornithine decreased it. Esterification of the carboxyl group of N alpha-acyl-L-arginine enhanced its inactivating effect. When the ethyl ester of CAE was converted to an amide group, the effect was appreciably decreased. Modification of the carboxyl group was essential for the inactivation. The effectiveness of N alpha-acyl-L-arginine ethyl ester depends upon the length of the acyl group, with the optimum length for the inactivation of HBsAg being C12 to C14. In addition to CAE, N alpha-lauroyl-L-lysine ethyl ester and N alpha-cocoyl-L-arginine amide were found to be strong inactivators of HBsAg. Significant inactivating effects on HBsAg were not observed in many anionic detergents containing an amino acid. These results suggest that for strongly inactivating HBsAg, a compound should contain a special amino acid, such as L-arginine, and a long acyl group and exhibit a cationic property.
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PMID:Influence of chemical modification of N alpha-cocoyl-L-arginine ethyl ester on its hepatitis B surface antigen-inactivating effect. 744 15

Identification of cell surface viral binding proteins is important for understanding viral attachment and internalization. We have fused the pre-S domain of the duck hepatitis B virus (DHBV) large envelope protein to glutathione S-transferase and demonstrated a 170-kDa binding protein (p170) in [35S]methionine-labeled duck hepatocyte lysates. This glycoprotein was found abundantly in all extrahepatic tissues infectible with DHBV and in some noninfectible tissues, though it is not secreted into the blood. The interaction of pre-S fusion protein with p170 was competitively inhibited by wild-type DHBV in a dose-dependent manner. In addition, infection of hepatocytes with DHBV blocked the binding of pre-S fusion protein to p170, which suggests a biological role for p170 during natural infection. The p170 binding site was mapped to a conserved sequence of 16 amino acid residues (positions 87 to 102) by using 24 pre-S deletion mutants; this binding domain coincides with a major virus-neutralizing antibody epitope. Furthermore, site-directed mutagenesis revealed that an arginine residue at position 97 is critical for p170 binding. p170 was purified by a combination of ion-exchange and affinity chromatographies, and four peptide sequences were obtained. Two peptides showed significant similarities to human and animal carboxypeptides H, M, and N. Taken together, these results raise the possibility that the p170 binding protein is important during the replication cycle of DHBV.
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PMID:Interaction between duck hepatitis B virus and a 170-kilodalton cellular protein is mediated through a neutralizing epitope of the pre-S region and occurs during viral infection. 747 30

Perinatal infection with variants of hepatitis B virus occurs despite combined immunoprophylaxis with hepatitis B immunoglobulin and currently licensed plasma-derived and recombinant yeast hepatitis B vaccines. Several variants have been detected during a large study of infants born to carrier mothers in Singapore. The most frequent variant was a virus in which a single amino acid substitution Gly to Arg occurred at amino acid position 145 of the outer protein coat of the virus. Similar mutations have been described in Italy, Japan, the USA and a number of other countries. The emergence of antibody escape mutants is a cause for concern for the detection of virus and possibly for future immunization programmes.
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PMID:Molecular epidemiology of hepatitis B virus vaccine variants in Singapore. 748 83

Core particles of hepatitis B virus are assembled from dimers of a single 185-residue (subtype adw) viral capsid or core protein (p21.5) which possesses two distinct domains: residues 1 to 144 form a minimal capsid assembly domain, and the arginine-rich, carboxyl-terminal residues 150 to 185 form a protamine-like domain that mediates nucleic acid binding. Little is known about the topography of the p21.5 polypeptide within either the p21.5 capsids or dimers. Here, using site-specific proteases and monoclonal antibodies, we have defined the accessibility of p21.5 residues in dimers and capsids assembled from wild-type and mutant hepatitis B virus core proteins in Xenopus oocytes and in vitro. The data reveal the protamine region to be accessible to external reagents in p21.5 dimers but largely cryptic in wild-type capsids. Strikingly, in capsids the only protease target region was a 9-residue peptide covering p21.5 residues Glu-145 to Asp-153, which falls largely between the two core protein domains. By analogy with protease-sensitive interdomain regions in other proteins, we propose that this peptide constitutes a hinge between the assembly and nucleic acid binding domains of p21.5. We further found that deletion or replacement of the terminal Cys-185 residue greatly increased surface exposure of the protamine tails in capsids, suggesting that a known disulfide linkage involving this residue tethers the protamine region inside the core particles. We propose that disruption of this disulfide linkage allows the protamine region to appear transiently on the surface of the core particle.
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PMID:A protease-sensitive hinge linking the two domains of the hepatitis B virus core protein is exposed on the viral capsid surface. 752 91

The detection of a fatal case of reactivation of hepatitis B, in a previously vaccinated Indonesian patient after withdrawal of chemotherapy for lymphoma, was delayed because HBsAg was negative in a widely used monoclonal-antibody-based ELISA. The serum was later found to be strongly reactive for HBsAg by the polyclonal radioimmunoassay and for HBV DNA. PCR sequencing revealed a substitution of arginine for glycine at position 145 of HBsAg in the major neutralising epitope cluster, the a determinant, as well as a 2-aminoacid insertion of asparagine and threonine between positions 122 and 123, immediately upstream of this determinant.
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PMID:Fulminant reactivation of hepatitis B due to envelope protein mutant that escaped detection by monoclonal HBsAg ELISA. 763 Feb 79

A 900bp DNA fragment of hepatitis B virus surface antigen gene by digesting BamHI and HpaI sites on the open reading frame of HBV DNA on plasmid pEcob6 containing double copes of HBV DNA was cloned into SmaI site on the phagmide vector pBluescribt SK +. From this recombinant vector, 12 hepatitis B virus surface antigen gene mutants were obtained by oligonucleotide-mediated site directed mutagenesis. The expression vector-pMEP4HBS mutants are constructed by sub-cloning all of these mutant fragments of hepatitis B virus surface antigen gene on pBluescritSK+HBSM into BsmHI and KpnI sites on an Epstein-Barr virus based on eukaryotic expression vector-pMEp4. The vector pMEp4HBSMs were transfected to human hepatocellular carcinoma cell line-HepG2 by calcium phosphate mediated transfection, and resistant cell clones were obtained 3 weeks after selecting by hygromycine B. The results of detection of HBsAg excreted by resistant cell clones with monoclonal antibody to HBsAg showed that all antibody escape mutants of HBsAg except mutant 145R, a substitution of arginine for glycine at amino acid 145 position in HBsAg, were positive.
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PMID:[Expression of 12 antibody escape mutants of hepatitis B virus surface antigen gene in mammalian cell by using an Epstein-Barr based vector]. 755 56


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