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Biomedical subjects

J W Shih

Publications and source records attributed to J W Shih.

At least 109 records · Page 6Linked to original sources
PubMed1979

Demonstration and partial characterization of 22-nm HBsAg and Dane particles of subtype HBsAg/ady.

The present paper describes the demonstration of d, y, w, and r HBsAg determinants in one serum. It was shown that there are two populations of HBsAg particles: HBsAg/ad and HBsAg/ady. All complete Dane particles were of subtype HBsAg/ady. Further characterization of HBsAg/ady particles did not reveal morphologic differences when they were compared with HBsAg/ad and HBsAg/ay particles. An HBsAg/ady phenotype may be the result of a double infection with hepatitis B viruses or exchanges of DNA sequences that determine HBsAg/ay and HBsAg/ad to form a new genotype.

Adult↗
PubMed1978

Radioimmunoassay for the detection of the antibody against hepatitis-B-core antigen (anti-HBc).

In this paper we describe a new sensitive solid phase radioimmunoassay for the detection of anti-HBc. This test was shown to be more sensitive than the widely used immune adherence hemagglutination test (IAHA) and at least as sensitive as the radioimmunoassay using the blocking principle. The new test system appears to be very useful to screen larger groups of individuals (e.g. blood donors) for the presence of anti-HBc.

Antibodies↗
PubMed1978

Antigenicity of the major polypeptides of hepatitis B surface antigen (HBsAg).

The major polypeptides (P-1, P-2, and P-6) of HBsAg were isolated from purified preparations of 22-nm HBsAg particles, iodinated, and analyzed by double-antibody radioimmunoprecipitation assays for the presence of hepatitis B virus (HBV)-specific antigens. Each polypeptide fraction contained both group (a) and subtype (d) specific determinants in common by virtue of their immunoreaction with antiserum to native HBsAg and antisera to the other structural polypeptides. The antigenic and structural similarities of the HBsAg polypeptides establish that they are not each unique gene products of the HBV genome.

Antigens↗
PubMed1977

Expression of hepatitis B virus-specific markers in asymptomatic hepatitis B surface antigen carriers.

A study was undertaken to assess the state of hepatitis B virus infection in a group of asymptomatic hepatitis B surface antigen (HBsAg) carriers. This study confirmed that the presence of hepatitis B e antigen (HBeAg) in serum was closely associated with serum HBsAg-specific deoxyribonucleic acid polymerase activity, hepatitis B core antigen (HBcAg) in serum and liver cell nuclei, and a histological picture of chronic hepatitis. No HBsAg-specific deoxyribonucleic acid polymerase activity or HBcAg was detected in highly concentrated anti-HBe-positive sera. In addition, liver biopsy specimens from carriers with anti-HBe were negative for HbcAg by immunofluorescence, and the liver histology was either normal or revealed only fatty changes. These data indicate that the anti-HBe-positive sera contained either no Dane particles or, if present, at least a 500-fold-lower concentration of Dane particles than that found in HBeAg-positive sera.

Carrier State↗
PubMed1977

Proteins of hepatitis B surface antigen.

Purified 22-nm forms of hepatitis B surface antigen (Hbsag) representing the three major antigenic subtypes (adw, ayw, and adr) were analyzed for their constituent polypeptides by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. No consistent difference in either the number or relative distributions of the polypeptides was observed for the various subtypes. Seven polypeptides were designated as P-1 through P-7 in order of their decreasing mobilities. By comparison with protein standards, their molecular weights were estimated as 23, 29.5, 36, 41.5, 53.5, 72, and 97 thousand. The P-1 and P-2 components represented the major polypeptides; P-2 and P-5 might by glycoproteins, based on their reaction with periodic acid-Shiff reagent. Each polypeptide contains cysteine residues. HBSAg was radiolabeled with 3H or 14C by reductive methylation or iodinated with 125I by the chloramine-T or lactoperoxidase procedures. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of labeled HBSAg yielded patterns identical to those obtained with protein stain. Comparison of HBSAg labeled by the chloramine-T and lactoperoxide procedures indicated that there was no distinction between internal or external components within the 22-nm structure.

Cysteine↗
PubMed1977

Proteins of hepatitis B surface antigen: amino acid compositions of the major polypeptides.

The major polypeptides isolated from two different preparations of hepatitis B surface antigen/adw were analyzed for their amino acid compositions. The results indicated a high degree of compositional relatedness between the P-1 (23,000, molecular weight) and P-2 (29,500, molecular weight) polypeptides for each of the two preparations. A considerable proportion of the major P-1 and P-2 polypeptides may be composed of a common structure. No amino sugars were detected in the preparations of isolated polypeptides.

Amino Acids↗
PubMed1977

Immunochemistry and polypeptide composition of hepatitis B core antigen (HBc Ag).

Core particles were isolated from a nuclear extract of a hepatitis B-infected liver labeled with 125I by using chloramine-T and further purified by rate zonal sedimentation on sucrose gradients. Iodinated HBcAg was used as a ligand in a sensitive double-antibody radioimmunoprecipitation (RIP) assay for antibody to HBcAg. The specificity of the RIP reaction was evaluated using defined anti-HBc sera and paired sera from six well-documented cases of hepatitis B infection. The polypeptide composition of the iodinated antigen was examined by SDS-polyacrylamide gel electrophoresis of solubilized complexes of 125I-HBcAg and anti-HBc. Two major polypeptides with apparent m.w. of 17,000 and 35,000 daltons were observed and designated as cP-1 and cP-2, respectively.

Antibodies, Viral↗
PubMed1977

The demonstration of subtype (D or Y)-specific determinants on the surface of the presumed hepatitis B virus.

Dane particles isolated from the sera of HBsAg/ad and HBsAg/ay carriers were reacted with monospecific antibodies to the d and y subtype-specific determinants of HBsAg/. Dane particles from HBsAg/ad expressed the d determinant on their surfaces and those from HBsAg/ay sera contained the y specificity. Both complete (DNA-P and HBcAg) and defective (HBcAg alone) Dane particles expressed the subtype-specific determinants.

Epitopes↗
PubMed1976

Characterization of antibodies to the structural polypeptides of HGSAg: evidence for subtype-specific determinants.

Antisera prepared in guinea pigs to the structural polypeptides of HBAAg/adw and HBSAg/ayw were examined by a modified passive hemagglutination assay for antibodies to the subtype-specific d and y determinants. All of the isolated polypeptide fractions stimulated antibodies to both group specific and subtype-specific antigens of the native HBSAg particle from which they were derived. These data indicate that the polypeptides have similarities in their immunochemical structure.

Animals↗
PubMed1975

The N, O-diacetylmuramidase of chalaropsis species. IV. Tryptic peptides.

Lysozyme Ch was hydrolyzed with trypsin in 2 M urea and the resulting peptides were separated by a combination of gel filtration and ion exchange chromatography. Ten peptides and free lysine were produced by tryptic action. The enzyme has 5 arginine and 4 lysine residues per molecule and one of the peptides arose from a chymotryptic-like cleavage of a tyrosyl-seryl bond near the amino-terminal end of the enzyme. The entire molecule is accounted for by the tryptic peptides, which have been ordered withing the peptides obtained by cyanogen bromide cleavage of the molecule.

Acetates↗
PubMed1975

Immunochemistry of hepatitis B surface antigen (HBsAg): preparation and characterization of antibodies to the constituent polypeptides.

The structural polypeptides of HBsAg were shown to be immunogenic in guinea pigs. Purified 22-nm forms of the ad and any subtypes of HBsAg were solubilized under reducing conditions and electrophoresed in SDS-polyacrylamide gels. Individual polypeptides isolated from both HBsAg/ad and HBsAg/ay subtypes were used to hyperimmunize guinea pigs using Freund's complete adjuvant. All animals produced specific antibodies against native HBsAg as determined by complement fixation, passive hemagglutination, and double-antibody radioimmunoprecipitation assays. Each polypeptide contained within its structure the group-specific HBsAg determinant, a. Equilibrium competitive inhibition studies were conducted to determine the relative affinities of antisera produced against the major HBsAg polypeptides P-1, P-2, and P-6 (23,000, 29,000, and 72,000 daltons, respectively).

Animals↗
PubMedDate not supplied

Woodchuck hepatitis and hepatocellular carcinoma: correlation of histologic with virologic observations.

The livers of 33 captive woodchucks were examined histologically in 30 biopsy and 10 autopsy specimens and the findings were correlated with serum determinations for woodchuck hepatitis virus (WHV), surface antigen (WHsAg) and antibody (anti-WHs), and WHV DNA and DNA polymerase. The liver appeared normal in all 3 serum-negative animals, 7 of 16 with indeterminate WHV status, and 1 of 4 with anti-WHs, but not in 10 animals with WHsAg, WHV DNA, and DNA polymerase. Mild hepatic inflammation was found in 7 woodchucks with indeterminate status, 4 with anti-WHs, and 2 with each marker of WHV infection. Significant inflammation was found in 2 of indeterminate status and 4 with every marker, whereas more severe lesions (2 of chronic active type) occurred, almost always in autopsy specimens, in 8 animals with every marker. Eight of 10 animals with all markers had orcein-positive inclusions (Shikata's technique) and 6 had hepatocellular carcinoma associated with acute and chronic hepatic inflammation and, usually, neoplastic nodules in the noncarcinomatous parenchyma. Features distinguishing the woodchuck lesion from human hepatitis B disease were: association of carcinoma with acute hepatic inflammation (but not with cirrhosis) and DNA polymerase in the serum; transition to carcinoma from neoplastic nodules; conspicuous plasma-cellular reaction of hepatic inflammation, and hematopoietic cells in the tumor. Significant hepatic lesions in the woodchucks were regularly associated with serum WHsAg, WHV DNA, and DNA polymerase. In contrast to man, hepatocellular carcinoma in woodchucks was regularly associated with these markers of active viral replication. The nature of the orcein-positive inclusions requires elucidation, although they may assist in screening for similar viruses in other species. The woodchuck may help in the study of the relation between hepatocellular carcinoma and hepatitis B, including the possibility of cocarcinogenic factors.

Animals↗
PubMedDate not supplied

The delta agent: HBsAg particles with delta antigen and RNA in the serum of an HBV carrier.

The hepatitis B virus-associated delta antigen was detected in the serum of a young female drug addict with acute hepatitis and a previous history of hepatitis B surface antigen carrier. Delta antigen was associated with a 35- to 37-nm subpopulation of hepatitis B surface antigen particles which banded at a density of 1.25 gm per cm3 of CsCl and contained a small RNA of approximately 5.5 X 10(5) molecular weight. This report demonstrates that delta antigen is associated with a unique subpopulation of hepatitis B surface antigen particles and small RNA in human serum.

Adult↗
PubMedDate not supplied

Identification of a murine CD4+ T-lymphocyte response site in hepatitis C virus core protein.

The T cell response to a recombinant HCV truncated core protein (cp1-10) was measured in a proliferation assay. Based on a 10-fold greater response to this truncated core protein than to its shorter form (cp1-8), a predominant epitope was mapped to the carboxyl quarter of this sequence. This epitope was further mapped to a synthetic peptide corresponding to amino acids 121-140 of the core protein. The peptide was antigenic for T cells of all three H-2 types tested, H-2 r, b and d, and the proliferating T cells were CD4+. Besides inducing specific proliferation in vitro, peptide aa121-140 can prime helper T cells in vivo. When boosted with core protein, mice primed with peptide produced 64-fold higher antibody titer than without priming in 1 week. The identification of a broadly immunogenic T cell helper epitope on core protein may be important for vaccine design against HCV.

Amino Acid Sequence↗
PubMedDate not supplied

Genetic and serologic relatedness between Mycoplasma fermentans strains and a mycoplasma recently identified in tissues of AIDS and non-AIDS patients.

A mycoplasma previously identified in the tissues of both AIDS and non-AIDS patients dying of an acute fatal disease was earlier shown to share some biologic and genetic properties with a strain of Mycoplasma fermentans, an organism occurring infrequently in the human lower urogenital tract. More extensive genetic and serologic comparisons using DNA/DNA hybridization, DNA base composition (guanine + cytosine), restriction endonuclease DNA analysis, cellular protein patterns and metabolism inhibition serologic procedures confirm that the organism previously designated as "Mycoplasma incognitus" (Mi) is indeed very closely related to strains of M. fermentans. While the genetic and serologic features observed among the newly isolated mycoplasma and two M. fermentans strains suggest a species relationship, it now seems useful to re-examine the biological activities of other freshly isolated M. fermentans strains from man.

Acquired Immunodeficiency Syndrome↗