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Biomedical subjects

M Mayumi

Publications and source records attributed to M Mayumi.

At least 253 records · Page 14Linked to original sources
PubMed1986

A synthetic peptide vaccine involving the product of the pre-S(2) region of hepatitis B virus DNA: protective efficacy in chimpanzees.

The S gene encoding the major surface polypeptide of hepatitis B virus is preceded by the region pre-S(2) with a capacity to code for 55 amino acid residues. In the product of region pre-S(2), the sequence of 19 amino acid residues (amino acids 14-32 from the N terminus) representing an area of high local hydrophilicity is shared by viral strains of subtypes adr, ayw, and ayr; residue 22, phenylalanine, is replaced by leucine in a strain of the other subtype, adw. A synthetic peptide vaccine involving these 19 amino acid residues, when given to two chimpanzees, raised antibodies that bound to viral particles and protected the animals from challenge with 10(6) chimpanzee infectious doses of hepatitis B virus.

Animals↗
PubMed1986

Changing pattern of age-specific prevalence of hepatitis B surface antigen and corresponding antibody in Japan.

During the period 1978-1984 in Japan, the prevalence of hepatitis B surface antigen (HBsAg) in age groups below age 15 years was 18/2,550 (0.7%), and it was particularly low in the group below age 5 years (2/706 (0.3%)). The low prevalence of HBsAg in children under 15 years of age contrasted sharply with the much higher prevalence in persons age 15 years and older (36/2,050 (1.8%)). In accord with this, the prevalence of antibody to hepatitis B surface antigen (anti-HBs) was much lower in children below age 15 years than that in persons 15 years of age and older (29/2,550 (1.1%) vs. 242/2,050 (11.8%)). Furthermore, the prevalence of hepatitis B viral markers in 1978-1984 was lower than that during the period from 1972-1977 in every age group. A total of 13 (81%) of 16 mothers of carrier children, identified in 1978-1984, were positive both for HBsAg and hepatitis B e antigen in their sera. Now that mother-to-baby transmission appears to be the main route for establishing the persistent carrier state, its interruption should reduce the reservoir of hepatitis B virus, toward its eventual eradication, in Japan.

Adolescent↗
PubMed1986

Structure of asparagine-linked sugar chains in the major polypeptide of hepatitis B surface antigen.

Asparagine-linked sugar chains were quantitatively released from hepatitis B surface antigen on hydrazinolysis followed by N-acetylation and NaB3H4 reduction. The released oligosaccharides were composed of two major sialylated components and a trace of a neutral component. From the results of the combination of sequential exoglycosidase digestion and methylation analysis, the structures of the acidic and the neutral components were deduced to be NeuAc alpha 2----6Gal beta 1----4GlcNAc beta 1----2Man alpha 1----3(+/- NeuAc alpha 2----6Gal beta 1----4GlcNAc beta 1----2Man alpha 1----6)Man beta 1----4GlcNAc beta 1----4GlcNAcOT and Gal beta 1----4GlcNAc beta 1----2Man alpha 1----3(Gal beta 1----4GlcNAc beta 1----2Man alpha 1----6)Man beta 1----4GlcNAc beta 1----4GlcNAcOT, respectively.

Antigens, Surface↗
PubMed1986

Nucleotide sequence of a cloned hepatitis B virus genome, subtype ayr: comparison with genomes of the other three subtypes.

The entire nucleotide sequence of genomic DNA was determined for hepatitis B virus (HBV) of subtype ayr, which had been derived from the blood of a Japanese asymptomatic carrier. The genome was 3215 nucleotides long, and differed in DNA sequence by 10% from that of subtypes adw or ayw, but by only 2% from that of subtype adr. Amino acid sequences coded for by the S, C, P and X genes, as well as by the pre-S region, closely resembled those of subtype adr, indicating that the evolution of HBV/ayr from HBV/adr was more recent than the differentiation of the other three subtypes. In the product of the S gene, the mutually exclusive subtypic determinants of the surface antigen, d and y, were associated with variation of amino acid residues at only the 68th and 122nd positions from the N terminus, in contrast to the variation at as many as seven positions for the other set of subtypic determinants, w and r. Sequences representing high local hydrophilicity in the product of the S gene were involved in subtypic variation, although such sequences in the pre-S region were shared by HBV genomes of the various subtypes. In particular, a hydrophilic sequence of 19 amino acid residues, coded for by the pre-S(2) region and implicated in the presumed hepatotropism of HBV, was possessed in common by HBV/adr, HBV/ayr and HBV/ayw, and differed in HBV/adw by only one residue at the 9th position. This amino acid sequence appears to be a promising candidate for a synthetic peptide vaccine.

Amino Acid Sequence↗
PubMed1986

Lack of detectable reverse transcriptase activity in human and chimpanzee sera with a high infectivity for non-A, non-B hepatitis.

A serum sample from a patient with hepatitis and samples from two experimentally infected chimpanzees, all with a high infectivity for non-A, non-B hepatitis, were tested for reverse transcriptase. Biopsy confirmed that the hepatocytes of the chimpanzees that received these sera contained the characteristic tubular structures associated with non-A, non-B hepatitis. None of these three sera revealed detectable enzyme activity. We have not been able to confirm the association of reverse transcriptase activity with non-A, non-B hepatitis reported recently.

Animals↗
PubMed1986

Integration of region X of hepatitis B virus genome in human primary hepatocellular carcinomas propagated in nude mice.

Tissues of human primary hepatocellular carcinoma (PHC) from six patients infected with hepatitis B virus (HBV) were propagated in nude mice, as well as a strain of hepatitis B surface antigen-positive PHC (PLC/PRF/5). Integration of viral DNA into chromosomal DNA of tumour cells was evaluated by the capacity to hybridize with radiolabelled DNA probes, each representing fundamental parts of the HBV genome, that is S and C genes and regions pre-S and X. All PHC cells possessed region X integrated in their chromosomes. However, integration of the S gene, C gene and region pre-S was found in only six of the seven PHCs. Based on these findings, the integration of region X seems to be most closely associated with carcinogenesis in HBV infection.

Animals↗
PubMed1986

Small and large forms of hepatitis B e antigen in the serum: determination by two-site sandwich radioimmunoassay with monoclonal antibodies.

Serum samples containing hepatitis B e antigen (HBeAg) were subjected to electrophoresis in agarose, and fast-migrating 'small' HBeAg and slow-migrating 'large' IgG-associated HBeAg were pooled separately. HBeAg of each category was determined by a two-site radioimmunoassay that sandwiched HBeAg between monoclonal antibody (anti-HBe) against one epitope of HBeAg, fixed on a solid support, and anti-HBe against another epitope, labelled with radioiodine. Eighteen sera in which small HBeAg dominated revealed activities of hepatitis B surface antigen-associated DNA polymerase significantly higher than 14 sera in which large HBeAg dominated (logarithm of ct/min, mean +/- s.e. 3.36 +/- 0.08 versus 2.14 +/- 0.11, P less than 0.01). Shift from small HBeAg to large HBeAg was observed, along with the disappearance of DNA polymerase, in the serum from two carriers who seroconverted to anti-HBe.

Antibodies, Monoclonal↗
PubMed1985

A two-site sandwich radioimmunoassay of human gamma interferon with monoclonal antibodies.

Two monoclonal antibodies (nos. 6008 and 6016) were raised against human gamma interferon (IFN-gamma) derived from E. coli harboring the recombinant cDNA for IFN-gamma, and one (3710) against a synthetic peptide representing its C-terminus amino acid sequence of 20 residues. The monoclonal antibody against the synthetic peptide (3710) reacted either with IFN-gamma or the synthetic peptide. One monoclonal anti-IFN-gamma (6008) did not react with the synthetic peptide, while the other (6016) showed a weak binding with the peptide. The binding of the monoclonal antibody against the synthetic peptide (3710) with IFN-gamma was not inhibited by 6008, but to a certain extent by 6016. A 2-site '1-step' radioimmunoassay was developed in which 6008 was fixed on a solid-phase support, and the test sample together with radiolabeled 3710 was added for the binding with it. The assay was rapid with a sensitivity capable of detecting a few ng/ml of IFN-gamma.

Antibodies, Monoclonal↗
PubMed1985

Immunoglobulin A antibody against hepatitis B core antigen in the acute and persistent infection with hepatitis B virus.

Antibody to hepatitis B core antigen of immunoglobulin A class was determined in the serum of patients infected with hepatitis B virus by a sandwich-type solid-phase radioimmunoassay with monoclonal antibodies. The antibody, as defined by a sample to normal ratio greater than 2.1, was detected in all of 39 patients with acute hepatitis, with titers varying widely depending on the time of blood sampling. In persons with persistent infection, the antibody was detected in only 2 (4%) of 46 asymptomatic carriers of the virus, contrasting with the positivity in as many as 15 (41%) of 37 patients with chronic persistent hepatitis, in 45 (94%) of 48 patients with chronic active hepatitis, and in 40 (87%) of 46 patients with liver cirrhosis with or without hepatocellular carcinoma. The mean +/- SE titer of antibody in chronic persistent hepatitis (3.8 +/- 0.9) was significantly lower than those in chronic active hepatitis (13.8 +/- 3.2) and cirrhosis with or without carcinoma (25.6 +/- 6.1) (p less than 0.001). Based on the results obtained, the antibody may reflect hepatic injury in the persistent hepatitis B virus infection.

Antibodies, Monoclonal↗
PubMed1985

Hemagglutination assay of polypeptide coded by the pre-S region of hepatitis B virus DNA with monoclonal antibody: correlation of pre-S polypeptide with the receptor for polymerized human serum albumin in serums containing hepatitis B antigens.

The receptor for polymerized human as well as chimpanzee serum albumins has been identified on the 55-amino acid polypeptide coded by the pre-S region of hepatitis B virus DNA. Monoclonal antibodies were raised against a synthetic polypeptide of 19 amino acid residues representing a hydrophilic region of the pre-S amino acid sequence deduced from hepatitis B virus DNA. Sheep erythrocytes fixed with glutaraldehyde were coated with monoclonal antibody against the synthetic polypeptide to develop a hemagglutination assay for pre-S polypeptide. The pre-S polypeptide was detected in the serum containing hepatitis B surface antigen particles along with hepatitis B e antigen, with titers in parallel with those of the receptor for polymerized human serum albumin.

Animals↗
PubMed1984

A two-site sandwich radioimmunoassay of beta 2-microglobulin with monoclonal antibodies.

Among 21 batches of monoclonal antibodies raised against beta 2-microglobulin (anti-beta 2m), 6 reacted with soluble beta 2m, as well as with beta 2m present in association with HLA heavy chains on the surface of leukocytes. The remaining 15 anti-beta 2m antibodies bound with soluble beta 2m, but failed to react with beta 2m on the cell surface. No monoclonal anti-beta 2m antibodies revealed precipitin lines when they were tested against beta 2m in immunodiffusion. When 2 anti-beta 2m antibodies with different specificities were mixed together, however, they developed a precipitin line against beta 2m. Based on these observations, there was only 1 epitope on beta 2m that was available for the binding with a monoclonal anti-beta 2m antibody with either specificity. This allowed the development of a solid-phase radioimmunoassay in which beta 2m in test specimens was sandwiched between immobilized anti-beta 2m of 1 specificity and radiolabeled anti-beta 2m of a heterologous specificity in a single step. Monoclonal antibodies with at least 2 different specificities would be required for developing a sandwich-type immunoassay of polypeptides, such as beta 2m, that do not display 2 or more epitopes of the same specificity.

Animals↗
PubMed1984

T-cell regulation of IgG subclass expression by mitogen-induced plasma cells: soluble factors versus the T cells.

The human IgG subclasses expressed by plasma cells generated from circulating B cells in response to soluble T-cell factors were examined by immunofluorescence using subclass-specific monoclonal antibodies. Soluble T-cell factors were induced by a mixed lymphocyte reaction, pokeweed mitogen (PWM), or phytohemagglutinin. The distribution of IgG subclasses expressed by plasma cells induced by these factors was IgG2 greater than 75%, IgG1 less than 25%, IgG3 less than 1%, and IgG4 less than 1%. On the other hand, IgG1 was dominant when B cells were cultured with T cells and PWM: IgG1 approximately 70%, IgG2 approximately 20%, IgG3 approximately 8%, and IgG4 approximately 1%. The addition of different amounts of the T-cell factors to B cells in culture did not alter the predominance of IgG2 plasma-cell differentiation. These results suggest that T cells and their soluble factors may preferentially enhance terminal differentiation of different IgG B-cell subpopulations. In contrast, the ratio of IgA1 to IgA2 plasma-cell responses was approximately 1.5 to 1 regardless of whether the B-cell precursors were induced by T-cell factors or by the T cells plus PWM.

Adult↗
PubMed1984

Deposition of hepatitis B e antigen in membranous glomerulonephritis: identification by F(ab')2 fragments of monoclonal antibody.

The pathogenic ability of hepatitis B e antigen (HBeAg) to induce membranous glomerulonephritis was evaluated by the most specific method presently available. Monoclonal antibody was raised against HBeAg, and F(ab')2 fragments were obtained and labeled with fluorescence. By this reagent, 10 out of 16 patients with membranous glomerulonephritis with hepatitis B surface antigen in the serum revealed granular deposition of HBeAg along glomerular capillary walls. Among the cases with glomerular HBeAg deposits, nine had detectable HBeAg in the serum and one had antibody to HBeAg (anti-HBe). The specificity of HBeAg staining was ascertained by blocking and inhibition tests, and the fluoresceinated anti-HBe F(ab')2 reagent did not stain the glomerular immune deposits in the patients with membranous glomerulonephritis who did not carry hepatitis B virus (HBV). None of the studied patients showed deposition of hepatitis B surface or core antigens in the glomerulus. On the basis of these results, immune complexes involving HBeAg may induce membranous glomerulonephritis in persons who carry HBV.

Adolescent↗
PubMed1984

Beta-propiolactone for the inactivation of non-A/non-B type 1 hepatitis virus capable of inducing cytoplasmic tubular ultrastructures in chimpanzees.

Non-A/Non-B type 1 hepatitis virus may be recognized because it induces characteristic tubular ultrastructures in the hepatocyte cytoplasm of chimpanzees. 3 chimps received 0.1 ml of a chimp serum containing more than 100 chimp infecting units of non-A/non-B type 1 hepatitis virus after it had been treated with beta-propiolactone with or without combined ultraviolet irradiation. All of the chimps escaped infection throughout the observation period of 23 weeks. The treatment of the serum with beta-propiolactone at the mildest condition employed (0.05%, 4 degrees C, 20 min) was still effective in inactivating the virus. The susceptibility of the chimps was ascertained by the subsequent challenge with 0.1 ml of the untreated serum which invariably induced non-A/non-B type 1 hepatitis in them. On the basis of these results, beta-propiolactone was extremely efficacious for the cold sterilization of non-A/non-B type 1 hepatitis virus.

Animals↗
PubMed1984

DNA-protein complex from hepatitis B virus.

Hepatitis B virus (HBV) DNA labelled with [3H] or [alpha-32P]dTTP in vitro was isolated from Dane particles by CsCl-guanidine hydrochloride density gradient centrifugation. Virtually all HBV DNA extracted as above contained a knob on the double-stranded region visible by electron microscopy. Proteinase K removes the know from HBV DNA. The HBV DNA-protein complex was efficiently bound to nitrocellulose membrane filters. When the radioactively labelled HBV DNA-protein complex was digested with restriction endonuclease Hae III or Hind II and subjected to polyacrylamide gel electrophoresis, some radioactivity did not enter the gel. Restriction endonuclease fragments did not remain on the top of the gel after proteinase K treatment and no new band was detected. The possible role of the knob protein in the replication of HBV DNA is discussed.

Centrifugation, Density Gradient↗
PubMed1984

[Clinical evaluation on ceftriaxone in the field of pediatrics].

Ceftriaxone (Ro 13-9904, CTRX), a new parenteral cephalosporin, was used for pediatric infections and the following results were obtained. CTRX was administered twice daily by intravenous injection with about 20 mg/kg in 6 cases consisting of 2 cases with purulent lymphadenitis of the neck, 2 with urinary tract infection, 1 with sepsis and pyelonephritis and 1 with sepsis and purulent lymphadenitis of the neck. The result was excellent in 4 and good in 2. One case with H. influenzae meningitis, receiving 50 mg/kg CTRX by intravenous injection twice daily, showed an excellent response without having any sequela. Among those mentioned above, diarrhea in 2 cases and elevated GOT and GPT in 2 were observed, all of which were transitory and not serious. The blood level of CTRX at 1/2, 1, 2, 4, 6 and 8 hours after intravenous injection with 20 mg/kg to a girl of 8 years and 8 months of age with urinary tract infection was 114, 86, 70, 42, 29 and 21.8 micrograms/ml, respectively. The half-life time was 3.5 hours while the urinary recovery rate up to 6 hours was 58.0%. The concentration in the cerebrospinal fluid of 1 case with H. influenzae meningitis ranged from 2.1 to 8.2 micrograms/ml at 3 hours after administration and from 1.15 to 2.65 micrograms/ml after about 12 hours (prior to the next administration). The above-mentioned results suggest that CTRX is a new antibiotic useful for pediatric infections caused with susceptible bacteria and is effective by intravenous injection with 10 mg/kg twice daily for moderate infections and with 20 mg/kg twice daily for severe ones, except for meningitis. As for purulent meningitis, the administration dosage and frequency will have to be further examined based on the intravenous injection with 50 mg/kg twice daily.

Bacterial Infections↗
PubMed1984

Incidences of HBeAg and anti-HBe in, and clinical course of hepatitis B virus carriers.

A total of 336 hepatitis B virus (HBV) carriers were followed for more than 3 years with serial measurements of serological markers of HBV to determine the correlation between their clinical course and the HBeAg-anti-HBe system. In all, 139 had hepatitis B e antigen (HBeAg) at the beginning of the study. During the study, 30 of 139 HBeAg-positive carriers became HBeAg negative and subsequently gave a positive reaction for antibody to HBeAg (anti-HBe). The rate of seroconversion was 3.6% per year. Two types of profile of seroconversion were observed, rapid and gradual. No significant differences were observed in the incidences of HBeAg and anti-HBe in HBV carriers with or without liver cirrhosis (LC) and hepatocellular carcinoma (HCC). These findings do not support the report by Chung et al. (1983, J. Med. Virol. 11: 99-104) that a prolonged replicative phase of chronic HBV infection is essential for the occurrence of HCC. Two HBV carriers were diagnosed as having HCC at the time of seroconversion from HBeAg to anti-HBe. This finding supports the reports by Coursaget et al. (1978, J. Clin. Microbiol. 7: 394-395) and Musca et al. (1983, Hepatogastroenterology 30: 3-5) that actively replicating HBV sometimes becomes defective during the course of malignant transformation.

Adolescent↗