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Biomedical subjects

F Tsuda

Publications and source records attributed to F Tsuda.

At least 127 records · Page 7Linked to original sources
PubMed1989

Combined hepatitis B immune globulin and vaccine for postexposure prophylaxis of accidental hepatitis B virus infection in hemodialysis staff members: comparison with immune globulin without vaccine in historical controls.

Twenty-three staff members serving in a hemodialysis unit were exposed accidentally to needlestick contaminated with blood containing hepatitis B surface antigen and hepatitis B e antigen, as well as high levels of DNA polymerase activity (greater than 100 cpm). They received hepatitis B vaccine (20 micrograms) simultaneously with hepatitis B immune globulin (5 ml, 200 IU per ml) within 48 hr after the exposure, and the vaccination was repeated at 1 and 3 months. The protective efficacy was compared with that in a past study in the same unit in which 33 members were given hepatitis B immune globulin alone within 48 hr after the exposure to blood with similarly high levels of DNA polymerase activity. No differences were noted in age or sex between the staff members who were vaccinated and those who were not, nor were there any differences between their inocula in the titers of hepatitis B virus markers. During 12 months after the accident, only one (4%) of the 23 vaccinated members contracted hepatitis B virus infection, at a frequency significantly lower than 11 (33%) of the 33 members who did not receive vaccine (p less than 0.02). These results indicate that hepatitis B vaccine, when given in combination with hepatitis B immune globulin, is efficacious for postexposure immunoprophylaxis of accidental infection.

Adult↗
PubMed1989

The loss of subtypic determinants in alleles, d/y or w/r, on hepatitis B surface antigen.

Hepatitis B surface antigen possesses the group-specific determinant called a and one or another member from each of two pairs of allelic determinants, d and y as well as w and r, thereby creating the four major subtypes, adw, adr, ayw and ayr. In the sequence of major surface antigen polypeptides made of 226 amino acid residues, lysine or arginine at amino acid position 122 specifies d or y determinant, and lysine or arginine at position 160 specifies w or r determinant, respectively. By means of site-directed mutagenesis and expression of mutant genes in cultured cells, the mechanism for the loss of subtypic determinants on surface antigens was investigated at the molecular level. A rare sample of surface antigen of subtype ad, devoid of w or r determinant, had asparagine at position 160. When it was converted to lysine, the surface antigen of subtype adw was obtained. Two samples of surface antigen were subtyped as ar. They lacked d determinant, despite having lysine at position 122 which usually specified it. They differed from all reported sequences of surface antigen in amino acid 144 or 145. They displayed d determinant when amino acid 144 was converted from glutamic acid to aspartic acid, or when amino acid 145 was changed from alanine to glycine. These results indicate that the key amino acid residue at position 122 or 160 is indispensable for the expression of subtypic determinants and that some distant residues are also crucially involved in conforming them.

Alleles↗
PubMed1989

Antigenic sites on the arginine-rich carboxyl-terminal domain of the capsid protein of hepatitis B virus distinct from hepatitis B core or e antigen.

The capsid protein of hepatitis B virus (P19) is made of 183 amino acids and carries the antigenic sites of hepatitis B core antigen (HBcAg) and hepatitis B e antigen (HBeAg) on the amino-terminal domain. The carboxyl-terminal domain of P19 (amino acids 150-183) is arginine-rich (47%) and faces the interior of the nucleocapsid for the binding with DNA. Monoclonal antibody was raised against an antigenic site on this protamine-like region of P19, which was distinct from HBcAg or HBeAg sites, and the novel antigenic site(s) was provisionally designated as hepatitis B inner core antigen (HBicAg). When P19 in a low concn (150 ng/ml) was immobilized on the solid surface, HBicAg sites were preserved, while HBcAg or HBcAg sites were no longer available on it. This allowed the detection of antibodies against HBicAg (anti-HBic), by sandwiching them between immobilized P19 and anti-IgG labeled with horseradish peroxidase. Anti-HBic was detected in sera from HBsAg carriers, typically those seropositive for antibody to HBeAg. A synthetic arginine-rich decapeptide, with a sequence of Arg-Arg-Arg-Gly-Arg-Ser-Pro-Arg-Arg-Arg, representing amino acids 150-159 of P19 and conserved in the majority of reported hepatitis B virus, absorbed the activity to bind with P19 in seven (44%) out of 16 sera containing anti-HBic. These results indicate that the decapeptide carries an HBicAg epitope and the remaining amino acid sequence of the arginine-rich carboxyl terminal domain (160-183) may be responsible for the other HBicAg epitopes.

Amino Acid Sequence↗
PubMed1989

Hepatitis B surface antigen with an excess or deficiency in subtypic determinants in sera from asymptomatic carriers in Japan.

Using the solid-phase enzyme immunoassay with monoclonal antibodies, hepatitis B surface antigen (HBsAg) was subtyped in sera from 5082 asymptomatic carriers who donated blood units at regional blood centers in Japan. Among them, 5004 sera contained HBsAg of a regular subtype, i.e., adw, adr, ayw or ayr, while 74 contained HBsAg with excessive subtypic determinants, such as adyw, adyr, adwr, aywr, or adywr. The presence of subtypic determinants on the selfsame particle was ascertained by sandwiching HBsAg between two monoclonal antibodies of distinct subtypic specificities. The remaining 4 sera contained HBsAg that possessed only one subtypic determinant, such as ad, ar or aw. HBsAg particles of atypical subtypes would have been given rise to by a point mutation in the S gene involving the codons regulating subtypic specificities.

Antibodies, Monoclonal↗
PubMed1988

Typing hepatitis B virus by homology in nucleotide sequence: comparison of surface antigen subtypes.

The complete nucleotide sequences of the DNA of three hepatitis B virus (HBV) genomes of subtype adw, cloned from plasma samples of asymptomatic carriers living in the mainland and Okinawa Prefecture of Japan and Indonesia were determined. All three comprised 3215 bp and differed in sequence by only 3.9 to 5.6%. When these isolates were compared with the reported sequences of two HBV genomes of the same subtype derived from American carriers, however, the differences were greater (8.3 to 9.3% to an extent comparable with the nucleotide divergence between an HBV genome of subtype adw and that of a heterotypic subtype, such as adr, ayw or ayr. A total of 18 HBV genomes of various subtypes, including the three described here, 10 reported previously and five unpublished ones, were classified into four groups based on an inter-group divergence in nucleotide sequence of 8% or greater: group A (two adw genomes), group B (four adw), group C (three adw, four adr and one ayr) and group D (four ayw). Thus, the nine genomes of HBV subtype adw were distributed into three groups with considerably different sequences. These results indicate that the four major antigenically defined subtypes of envelope polypeptide do not reflect true genotypic variation of HBV. The fact that d to y, as well as w to r, subtypic change can be induced by an A----G point mutation at nucleotides 365 and 479 in the S gene, respectively, supports this view.

Amino Acid Sequence↗
PubMed1988

Antibody against the translation product of the pre-S2 region of hepatitis B virus and the resolution of infection after accidental needlestick exposure.

During a 5-yr period before the introduction of post-exposure immunoprophylaxis of hepatitis B virus (HBV), 363 medical personnel contracted infection after exposure to a contaminated needlestick. Among them, five (1.4%) developed a persistent carrier state, and they were followed for antibodies against translation product of the pre-S2 region (anti-pre-S2) by the enzyme immunoassay with native viral polypeptides. The consecutive seven cases in whom infection was terminated served as controls. In the acute phase, the levels of IgM and IgG anti-pre-S2 were significantly higher in the seven in whom infection resolved than in the five in whom infection persisted (mean sample:normal ratio, 11.1 +/- 4.4 vs 2.0 +/- 1.3 and 8.7 +/- 7.0 vs 3.0 +/- 1.1, respectively, p less than 0.05). In convalescence, 6 months after the normalization of serum transaminase, IgG anti-pre-S2 was detected in a high titer in the staff members with resolved infection (27.4 +/- 38.5), but was not detectable in those with persistent infection. On the basis of these observations, the intensity of humoral antibody response against the pre-S2 region product is closely correlated with the resolution of infection after exposure to HBV, and anti-pre-S2 persists in the circulation much longer than previously reported.

Accidents, Occupational↗
PubMed1987

A synthetic peptide coded for by the pre-S2 region of hepatitis B virus for adding immunogenicity to small spherical particles made of the product of the S gene.

Small spherical particles produced in the non-permissive phase of hepatitis B virus infection, when the viral genome is integrated into the chromosome of hosts, are rich in the product of the S gene, but poor in the product of the pre-S2 region. For the purpose of adding immunogenicity to spherical particles deficient in the pre-S2 region product, they were conjugated with a synthetic peptide of 19 amino acid residues. The peptide reproduced a hydrophilic area of the pre-S2 region product encoded by viral genomes of subtypes adr, ayw and ayr. The spherical particles supplemented with the pre-S2 peptide raised antibody to the pre-S2 region product in mice, in addition to antibody to the product of the S gene. Antibody to pre-S2 region product, prepared from sera of immunized mice by absorption with the S gene product, bound to spherical particles bearing pre-S2 region product, irrespective of adr, adw, ayw or ayr subtype, and agglutinated hepatitis B virions in immune electron microscopy. Based on the results obtained, the synthetic peptide may prove useful in adding protective efficacy to small spherical particles poor in pre-S2 region product.

Absorption↗
PubMed1987

Point mutation in the S gene of hepatitis B virus for a d/y or w/r subtypic change in two blood donors carrying a surface antigen of compound subtype adyr or adwr.

Genomes of hepatitis B virus (HBV) were cloned from the plasma of a blood donor who carried subviral particles of three distinct subtypes in the following proportions: adr, 25%; ayr, 63%; and adyr, 12%. HBV DNA clones were classified into two groups based on a difference at only one nucleotide in the S gene. Two clones had A as nucleotide 365 that formed part of the codon for lysine as amino acid residue 122 and produced a surface antigen of subtype adr in transfected NIH 3T3 cells. The remaining four clones had G determining the codon for arginine and produced a surface antigen of subtype ayr in transfected cells. Similarly, HBV genomes were cloned from the plasma of an individual who carried subviral particles of subtypes adr (71%) and adwr (29%). Two clones had T and A as nucleotides 476 and 479, respectively. The other seven clones had C and G as the respective nucleotides. Based on a comparison with previously reported HBV genomes of various subtypes, the mutation of nucleotide 479, forming part of the codon for lysine or arginine as amino acid residue 160, was deduced to determine the w or r subtype, respectively. When NIH 3T3 cells were transfected separately with the genome of subtype adw or adr, derived from plasma containing a surface antigen of subtype adwr, and then cocultured, they produced subviral particles of either subtype adw or adr. When cells were transfected with the genomes of subtypes adw and adr simultaneously, however, subviral particles were produced that possessed w and r determinants on the selfsame particles. These results attributed the d/y or w/r subtypic change to a point mutation in the S gene and favored coinfection of hepatocytes with an HBV genome and its mutant as the mechanism of compound subtypes.

Base Sequence↗
PubMed1987

[Ventricular volumes determined by single-photon emission computed tomography].

To determine right (RV) and left ventricular (LV) volumes, a new technique was developed using ECG-gated single-photon emission computed tomography (SPECT). RV volumes of nine patients and LV volumes of 22 patients measured by SPECT and biplane contrast cineangiography were compared. In addition, volume and ejection fraction (EF) of the RV and LV were obtained by SPECT for 10 normal controls, 21 patients with old myocardial infarction (OMI), eight patients with hypertrophic cardiomyopathy (HCM) and 12 patients with dilated cardiomyopathy (DCM), and these results were compared. The intracardiac blood pool was labeled with Tc-99m sodium pertechnetate and 32 images were recorded through 180 degrees by a rotating gamma-camera. End-diastolic and end-systolic counts during 50 msec were recorded during 50 or 60 cardiac cycles. These counting data were reconstructed as tomographic images of vertical long-axial slices with thickness of a pixel without any attenuation correction. The numbers of voxels within the % cut-off level were summed, and the sum was multiplied by the one voxel volume. The cut-off level for ventricular delineation was determined as 45% by phantom studies. 1. The values obtained from SPECT and contrast angiography correlated well. 2. In normal controls, LV end-diastolic and end-systolic volumes were significantly less than those of the RV (p less than 0.05, p less than 0.001) and LVEF was significantly greater than the RVEF (p less than 0.001). 3. In OMI (single vessel disease), both end-diastolic and end-systolic volumes of the LV were significantly greater than those of normals (p less than 0.01, p less than 0.001) and LVEF was significantly less. In HCM end-systolic volumes of the RV were significantly less (p less than 0.05) than those of the normals. 4. LV volume was greater and LVEF was extremely low both in DCM and in OMI (multivessel disease) compared to that of the normals. In DCM, RV end-systolic volumes was greater and RVEF was lower than that of OMI (multi-vessel disease), indicating the deterioration of RV contractility , primarily in DCM. From these findings, it was concluded that this noninvasive technique may be useful for estimating left and right ventricular volumes.

Adult↗
PubMed1987

Defective mutants of hepatitis B virus in the circulation of symptom-free carriers.

A total of 75 clones of hepatitis B virus (HBV) DNA were isolated from the plasma of 4 symptom-free carriers. Each set of clones from a carrier all possessed at least one complete genome, for which the entire nucleotide sequence was determined. A deletion of nucleotide sequence, spanning from 13 to 1071 base pairs, was detected in 17 clones (23%). As many as 16 of them had a deletion in the C gene, with or without the involvement of the P and X genes. The remaining one clone had a deletion restricted to the pre-S region. Accordingly, these defective mutants could not replicate themselves without help from complete HBV co-infecting the same hepatocyte. Defective mutants would have developed during the replication of HBV by reverse transcription of an RNA intermediate, and provide another evidence for a close similarity of HBV with retroviruses.

Chromosome Deletion↗
PubMed1986

A solid-phase enzyme immunoassay for the determination of IgM and IgG antibodies against translation products of pre-S1 and pre-S2 regions of hepatitis B virus.

The envelope of hepatitis B virus is coded for by pre-S1, pre-S2 regions and the S gene. A method was developed to determine antibody to the product of pre-S1 region (anti-pre-S1) and antibody to the product of pre-S2 region (anti-pre-S2), either of IgM or IgG class, by a solid-phase enzyme immunoassay. For the determination of anti-pre-S1, tubular particles containing translation products of pre-S1, pre-S2 regions and the S gene were broken into constituent envelope polypeptides and immobilized on a solid support. Serums were absorbed with spherical particles containing translation products of pre-S2 region and the S gene, obtained from plasma positive for hepatitis B e antigen (HBeAg) and deprived of particles carrying pre-S1 product by an affinity column. They were then tested for the binding with tubular polypeptides fixed on a solid support, and the bound antibody representing anti-pre-S1 was detected by monoclonal antibody to human IgM/mu or IgG/gamma labeled with horseradish peroxidase. For the determination of anti-pre-S2, test serums were absorbed with spherical particles containing the product of the S gene, obtained from plasma positive for antibody to HBeAg and deprived of particles bearing pre-S2 product by an affinity column. They were then tested for the binding with polypeptides, fixed on a solid support, composed of products of pre-S2 region and the S gene. The assay was applied to the determination of anti-pre-S1 and anti-pre-S2 of IgM or IgG class in asymptomatic carriers and in persons who had recovered from infection with hepatitis B virus.

Antibodies, Monoclonal↗
PubMed1986

Application of hepatitis B core particles produced by human primary hepatocellular carcinoma (PLC/342) propagated in nude mice to the determination of anti-HBc by passive hemagglutination.

Human primary hepatocellular carcinoma (PLC/342), carried by nude mice, produces hepatitis B core particles as well as hepatitis B surface antigen particles. Core particles purified form PLC/342 tumors displayed epitopes of hepatitis B core antigen (HBcAg) but not epitopes of hepatitis B e antigen (HBeAg) on their surface, unlike core particles prepared from Dane particles, derived from plasma of asymptomatic carriers, that expressed epitopes of both HBcAg and HBeAg. Core particles obtained from PLC/342 tumors were applied to the determination of antibody to HBcAg (anti-HBc) by passive hemagglutination. The assay detected anti-HBc not only in individuals with persistent infection with hepatitis B virus and in those who had recovered from transient infection, but also in patients with acute type B hepatitis, indicating that it can detect anti-HBc of either IgG or IgM class. A liberal availability of core particles from tumors carried by nude mice, taken together with an easy applicability of the method, would make the passive hemagglutination for anti-HBc a valuable tool in clinical and epidemiological studies, especially in places where sophisticated methods are not feasible.

Acute Disease↗
PubMed1986

Polypeptides coded for by the region pre-S and gene S of hepatitis B virus DNA with the receptor for polymerized human serum albumin: expression on hepatitis B particles produced in the HBeAg or anti-HBe phase of hepatitis B virus infection.

There are four polypeptides coded for by the region Pre-S and gene S on DNA of hepatitis B virus that carry the receptor for polymerized human serum albumin (poly-HSA), i.e., P31 and P39, as well as their glycosylated counterparts P35 and P43. With the use of monoclonal antibodies directed to Pre-S(1) sequence and Pre-S(2) sequence (bearing the receptor for poly-HSA), the content of these polypeptides, as well as their expression on the surface, was determined for hepatitis B particles of various categories. P39 and P43, carrying both Pre-S(1) and Pre-S(2) sequences, were contained abundantly in Dane and tubular particles, and to a much lesser extent in small spherical particles, all of which were purified from plasma containing hepatitis B e antigen (HBeAg). P31 and P35, carrying Pre-S(2) but not Pre-S(1) sequence, were contained comparably in these three categories of hepatitis B particles. In remarkable contrast, small spherical particles derived from plasma containing antibody to HBeAg were very low in the content of any Pre-S polypeptides. P31 and P39 showed higher activities for poly-HSA receptor than their glycosylated versions. When Dane particles were digested with trypsin, the poly-HSA receptor was deprived in parallel with the loss of antigenicity for Pre-S(2) sequence. The antigenicity for Pre-S(1) sequence was much less affected, and that for the product of gene S was virtually unchanged by the digestion.

Amino Acid Sequence↗
PubMed1986

A solid-phase enzyme immunoassay for the common and subtypic determinants of hepatitis B surface antigen with monoclonal antibodies.

Monoclonal antibodies were raised against the common (a) as well as subtypic determinants (d, y, w and r) of hepatitis B surface antigen (HBsAg). They were applied to subtyping HBsAg by sandwiching it between antibody against a fixed on a solid-phase support and antibody against one or other of d, y, w and r, linked to horseradish peroxidase. The assay was applied to evaluate antigenic specificities of the NIH and Japanese panels composed of 44 sera containing HBsAg particles of various subtypes. HBsAg particles of a hybrid subtype, adyr, were sandwiched between monoclonal antibody against d and that against y, thereby indicating that they possessed both d and y determinants on the selfsame particle. The expression of d and y determinants on hybrid HBsAg particles was much less than that on ordinary particles of adw, adr, ayw or ayr subtype.

Animals↗
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↗