PubMed Health⌕ Search

Biomedical subjects

S Usuda

Publications and source records attributed to S Usuda.

At least 73 records · Page 4Linked to original sources
PubMed1986

Large hepatitis B surface antigen polypeptides of Dane particles with the receptor for polymerized human serum albumin.

Large hepatitis B surface antigen polypeptides with apparent molecular sizes of 39,000 and 43,000 daltons (P39 and P43) were liberated from a purified preparation of Dane particles of subtype adr. They were tested for reactivity with monoclonal antibodies raised against three synthetic oligopeptides representing fundamental sequences of the pre-S region in deoxyribonucleic acid of hepatitis B virus (subtype adr), as well as with monoclonal antibody against the major surface antigen polypeptide (P22) coded for by the S gene. Both P39 and its glycosylated form P43 bound to all four monoclonal antibodies, thereby indicating that they were coded for by the sequence of 1200 nucleotides, from the second ATG codon in the pre-S region to the stop codon of the S gene. Both P39 and P43 bound to polymerized human and chimpanzee albumins, but not to polymerized albumin from species without susceptibility to hepatitis B virus. Due to their presence in Dane particles and the expression of a polyalbumin receptor, the immune responses against P39 and P43 may have significance in infection with hepatitis B virus and its immunoprophylaxis.

Antibodies, Monoclonal↗
PubMed1986

Translation products of pre-S(1), pre-S(2) regions and the S gene of hepatitis B virus: susceptibility of their antigenic activities to treatment with heat, urea, formalin or pepsin.

Hepatitis B subviral particles, purified from plasma of asymptomatic carriers seropositive for hepatitis B e antigen, were treated with various conditions reported for the processing of vaccines. Thereafter, antigenic activities displayed by the translation products of pre-S(1), pre-(2) regions and the S gene were determined with monoclonal antibodies, and the reactivity for polyalbumin receptor was tested. Heating at 100 degrees C for 1.5 min and then at 65 degrees C for 10 h preserved more than 1/2 of antigenic activities representing products of pre-S(1), pre-S(2) regions and the S gene. After incubation in the presence of 8 M urea at 37 degrees C for 4 h, more than 2/3 of antigenic activities still remained. The antigenic activity of the S gene product was decreased to 2/3 and that of pre-S(2) region product to 1/3, after treatment with formalin at the final concentration of 1:4000 at 37 degrees C for 72 h, whereas the activity of pre-S(1) region product was affected drastically. Although 1/5 of the antigenic activity of the S gene product survived the digestion with pepsin for 18 h, antigenic activities of pre-S(1) and pre-S(2) region products were destroyed almost completely. Polyalbumin receptor, borne by the pre-S(2) region product, was lost by pepsin digestion also. Based on the results obtained, heating may be most appropriate for sterilizing plasma-derived hepatitis B particles for use as a vaccine, because it is reliably virucidal and would not affect the protective efficacy to an extent as the other virucidal methods would.

Epitopes↗
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

A polypeptide containing 55 amino acid residues coded by the pre-S region of hepatitis B virus deoxyribonucleic acid bears the receptor for polymerized human as well as chimpanzee albumins.

The receptor for polymerized human and chimpanzee albumins has been identified on a hepatitis B surface antigen polypeptide of approximately 31,000 daltons. The polypeptide, designated P31, is composed of the major polypeptide of hepatitis B surface antigen (P22) and an additional, as yet unidentified, amino acid sequence. We split P31 with cyanogen bromide and obtained a polypeptide of approximately 8000 daltons (P8) that contained carbohydrate. P8 could bind to polymerized human and chimpanzee albumins, but not to polymerized albumins from animals without susceptibility to hepatitis B virus. The amino acid composition of P8 closely resembled that of 55 amino-acid sequence coded by the pre-S region in the deoxyribonucleic acid of hepatitis B virus. Using monoclonal antibody against P8, a solid-phase sandwich radioimmunoassay was developed for the specific determination of hepatitis B surface antigen bearing the receptor for polymerized albumin in the serum of patients with hepatitis B virus infection.

Amino Acid Sequence↗
PubMed1983

A two-site sandwich radioimmunoassay of human fibroblast (beta-) interferon with monoclonal antibodies.

Monoclonal antibodies were produced against human fibroblast (beta-)interferon (IFN-beta). Four of them were directed to the determinant designated a, while the remaining 3 to another determinant named b. An IFN molecule was found to bear one each of a and b determinants arranged in such a manner that the occupation of a with the corresponding antibody did not interfere with the binding of b to its corresponding antibody, and vice versa. This allowed the development of a 2-site sandwich radioimmunoassay in which antibody to b was immobilized on wells of a microtiter plate and the bound antigen was detected by the radiolabeled antibody to a. The 2-site sandwich radioimmunoassay detected, with a high sensitivity, IFN-beta either induced from fibroblast or produced by Escherichia coli harboring the gene of IFN-beta.

Animals↗
PubMed1983

Three-site sandwich radioimmunoassay with monoclonal antibodies for a sensitive determination of human alpha-fetoprotein.

Utilizing monoclonal antibodies against human alpha-fetoprotein, 3 distinct antigenic determinants were identified. These antigenic determinants, provisionally designated a, b and c, were arranged in such a manner that the binding of one determinant with the corresponding antibody did not inhibit, or only barely inhibited the binding of antibodies directed to the other 2 determinants. Monoclonal antibodies with 3 different specificities were, therefore, applied to develop a sandwich-type solid-phase radioimmunoassay of the antigen in which wells were coated with anti-a, and radiolabeled anti-b together with radiolabeled anti-c was employed to detect the bound antigen. The 3-site sandwich radioimmunoassay involving 3 different determinants gave a higher sensitivity than 2-site assays in which only anti-b or anti-c was employed as a radiolabeled reagent, because the radioactivity of the 2 labeled antibodies was added on the antigen bound to immobilized anti-a.

Antibodies, Monoclonal↗
PubMed1983

A pitfall in two-site sandwich 'one-step' immunoassay with monoclonal antibodies for the determination of human alpha-fetoprotein.

Utilizing monoclonal antibodies directed to 2 distinct antigenic determinants of the human alpha-fetoprotein (AFP), Uotila, Ruoslahti and Engvall developed the 2-site sandwich immunoassay. They found that due to the different specificities of monoclonal antibodies, 2 antigen-antibody reactions, AFP with immobilized antibody and AFP with labeled antibody, could be accomplished in a single step. We have found, however, that above a certain concentration, AFP detectable by their method decreased because the labeled antibody tended to bind with AFP that failed to react with the immobilized antibody. Consequently, 2 different AFP concentrations produced the same result, and an extremely high, still clinically expectable concentration gave a false negative result. Such an inhibition in high AFP concentrations was not observed in the conventional '2-step' immunoassay within the range of concentrations tested (0.1 ng-3 mg/ml). On the basis of these observations, the 2-site '1-step' immunoassay for AFP would have to be applied on multiple dilutions of the serum to avoid an erroneous interpretation of the results.

Animals↗
PubMed1983

Selective binding of YM-09151-2, a new potent neuroleptic, to D2-dopaminergic receptors.

Effects of YM-09151-2 and five other neuroleptics (haloperidol, spiperone, chlorpromazine, sulpiride and clozapine) on the binding of [3H]-ligands to nine different receptors (alpha 1-adrenergic, alpha 2-adrenergic, beta-adrenergic, muscarinic, D2-dopaminergic, H1-histaminergic, 5HT1-serotonergic, 5HT2-serotonergic and opiate receptors) and on dopamine-sensitive adenylate cyclase were determined using brain membranes in the rat, guinea-pig and dog. The affinity of YM-09151-2 for D2-receptors with a Ki value of 0.1 nM was more than 1000-times higher than that for the other receptors and dopamine-sensitive adenylate cyclase, and it was the greatest among the neuroleptics tested.

Adenylyl Cyclases↗
PubMed1983

Immunochemical structure of hepatitis B e antigen in the serum.

Hepatitis B e antigen (HBeAg) constitutes the nucleocapsid of hepatitis B virus (HBV) and occurs in association with plasma proteins, particularly with IgG, in the serum of persons infected with the virus. A polypeptide with an approximate m.w. of 15,500 (P15.5) is obtained either from HBeAg in the serum or from the nucleocapsid of HBV. P15.5 preparations from serum and virus resembled closely each other in the amino acid composition. The C-terminus amino acid sequence of P15.5 from serum was determined to be -Thr-Thr-Val-Val, whereas that from the virus ended with -Thr-Thr. The same sequence of four amino acid residues was found on the gene coding for the nucleopeptide of hepatitis B virus with a molecular size of 19,000 daltons (P19). P15.5 identified on the nucleotide sequence of P19 was composed of 149 amino acid residues with a calculated molecular size of 16,770 daltons. The gene coding for P19 had two -Asp-Pro-connections. By splitting these connections in P19 and P15.5 preparations with formic acid, smaller polypeptides were obtained with sizes predicted from the nucleotide sequence and with the N-terminus amino acid of proline as expected. One of two monoclonal antibodies raised against the core of Dane particles (HBcAg) bound with P15.5 preparations purified from serum and HBV. The IgG fraction from a human serum containing antibodies to HBcAg but not to HBeAg bound with P15.5 also. On the basis of the results obtained, the IgG molecules associated with P15.5 in the serum of persons infected with HBV may well represent the antibodies against HBcAg with limited specificities.

Amino Acid Sequence↗
PubMed1983

Dopamine receptor system involving adenylate cyclase in canine caudate nucleus.

Two distinct dopamine binding sites, referred to as D1 and D2, exist in canine caudate nucleus, as characterized by [3H]dopamine binding to the synaptic membrane fraction. D1 has the low affinity for dopamine with the dissociation constant of a few micromolar, whereas the affinity for D2 is about two orders of magnitude greater. Classical neuroleptics such as haloperidol and chlorpromazine have no selectivity in the inhibition of D1 and D2 binding, whereas a number of 2-methoxy benzamide derivatives which have been synthesized in our laboratories exhibit rather different selectivity. Correlation between the selectivity of those benzamide derivatives for the two sites and the inhibition of apomorphine-induced stereotypy in rats suggests that D1 is more responsible for the stereotypy. Photoaffinity labeling of D1 and D2 with [3H]dopamine demonstrates that the two sites are distinct entities. In the D1 system, the adenylate cyclase which is responsive to Gpp(NH)p can be dissociable by the treatment with GTP-Sepharose into a guanine nucleotide binding unit and a catalytic unit which is insensitive to Gpp(NH)p. The catalytic unit restores the responsiveness to Gpp(NH)p after preincubation with the nucleotide binding unit. Furthermore, endogenous cAMP-dependent phosphorylation of two particular proteins (protein Ia and Ib) is shown, which may be at least partly responsible for stereotypy and dopamine turnover in the caudate nucleus.

Adenylyl Cyclases↗
PubMed1982

Pharmacological studies on a new benzamide derivative, YM-09151-2, with potential neuroleptic properties.

The electrophysiological properties and cataleptogenicity of YM-09151-2 (N-[(2RS, 3RS)-1-benzyl-2-methyl-3-pyrrolidinyl]-5-chloro-2-methoxy-4-methylaminobenzamide) were studied in the cat. This drug inhibited the EEG arousal response to electrical stimulation of the mesencephalic reticular formation with the same potency as that of haloperidol, whereas chlorpromazine revealed a more potent central depressant action. The duration of the afterdischarge induced by electrical stimulation of the amygdaloid nucleus was initially shortened and thereafter prolonged by both YM-09151-2 and haloperidol. However, YM-09151-2 was less effective than haloperidol and chlorpromazine in both augmenting the spindle bursts produced by electrical stimulation of the caudate nucleus and antagonizing the inhibitory effect of L-DOPA on the caudate spindle, indicating a smaller effect of YM-09151-2 on the extrapyramidal dopaminergic system than that of the two neuroleptic drugs. In fact, YM-09151-2 produced no cataleptic behaviour in the cat even at a dose of 5 mg/kg (s.c.), although haloperidol and chlorpromazine caused catalepsy in doses of 0.5 and 5 mg/kg (s.c.), respectively. Sulpiride, chemically related to YM-09151-2, showed much weaker central actions than YM-09151-2. The results indicate that a new benzamide, YM-09151-2, has a potent neuroleptic effect with a slight central depressant activity and that the cataleptogenicity of the compound is weaker than that of haloperidol and of chlorpromazine.

Amygdala↗
PubMed1981

Neuroleptic properties of cis-N-(1-benzyl-2-methylpyrrolidin-3-yl)-5-chloro-2-methoxy-4-methylaminobenzamide (YM-09151-2) with selective antidopaminergic activity.

A new benzamide, cis-N-(1-benzyl-2-methylpyrrolidin - 3 - yl) - 5 - chloro - 2 - methoxy - 4 - methylaminobenzamide (YM-09151-2) exhibited more potent and longer-lasting inhibitory effects on apomorphine-induced behaviours (stereotyped behaviour, emesis and hypothermia), and methamphetamine-induced stereotyped behaviour, conditioned avoidance response and open field behaviour, conditioned avoidance response and open field behaviour than either structurally similar benzamides (YM-0850 and sulpiride) or classical neuroleptics [chlorpromazine (CPZ) and haloperidol(HPD)]. Such inhibitory effects of YM-09151-2 relative to cataleptogenicity were greater than those of CPz and HPD. In contrast, sulpiride elicited few of the neuroleptic effects described above. YM-09151-2, a potent inhibitor for dopamine-sensitive adenylate cyclase (Ki: 3.0 nM) reduced, in a selective manner, the binding of [3H]dopamine to the dopamine D1 receptor (Ki:4.8 nm) associated with adenylate cyclase rather than to the dopamine D2 receptor (Ki: 0.98 microM) independent of adenylate cyclase. Sulpiride, on the contrary, inhibited only the binding to the dopamine D2 receptor, CPZ and HPD antagonized [3H]dopamine nonselectively at the two distinct dopaminergic receptors. These results suggest that YM-09151-2 is a potent and long-lasting neuroleptic with a highly selective blocking action on the dopamine D1 receptor.

Animals↗