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Biomedical subjects

S Urasawa

Publications and source records attributed to S Urasawa.

At least 127 records · Page 7Linked to original sources
PubMed1984

Production of subgroup-specific monoclonal antibodies against human rotaviruses and their application to an enzyme-linked immunosorbent assay for subgroup determination.

Nonneutralizing monoclonal antibodies were prepared against two strains, S2 and YO, of human rotaviruses isolated in cell culture. S2-37 and YO-5 antibodies had subgroup I and subgroup II specificities, respectively. The remaining antibodies (S2-65, YO-71, YO-89, and YO-156) reacted commonly with all the rotaviruses examined. All of the monoclonal antibodies agglutinated exclusively single-shelled particles and immunoprecipitated 42,000-dalton protein, a major component of inner capsid. Using the three monoclonal antibodies (S2-37, YO-5, and YO-156), an enzyme-linked immunosorbent assay was developed for detecting and subgrouping human rotavirus isolates.

Antibodies, Monoclonal↗
PubMed1984

Serotype determination of human rotavirus isolates and antibody prevalence in pediatric population in Hokkaido, Japan.

Three different serotypes of human rotavirus isolates defined in our laboratory were compared by cross neutralization tests with human rotavirus serotypes established in the NIH, U.S.A. The results clearly demonstrated that our three serotypes correspond well to their serotypes Wa, DS-1 and M (or P). Using the three serotype-specific rabbit antisera, all of the 16 strains isolated to date could be assigned to one of those three serotypes. The prevalence of human rotavirus serotypes 1, 2 and 3 among inhabitants of Sapporo and its outskirts was investigated based on the results of neutralizing antibody distribution patterns by age using sera of non-infectious disease patients examined at the Sapporo Medical College Hospital. Neutralizing antibody titers were measured against four strains, KU and K8 (serotype 1), S2 (serotype 2) and YO (serotype 3). The results revealed that serum antibody titers against KU, K8 and YO strains rose with time after birth, reaching the highest antibody distribution levels in either the 3-5-year-old or 6-9-year-old age group, while antibody against S2 strain tended to be lower than that against the other three strains throughout all age ranges examined, with the highest level being shown in the adult group.

Adolescent↗
PubMed1983

Outbreak of infantile gastroenteritis due to type 40 adenovirus.

Genetic and antigenic characterisation was performed on a strain of adenovirus (EAd) isolated from an outbreak of gastroenteritis which occurred in an orphanage in the City of Sapporo, in the room housing the eldest children, who ranged in age from 14 to 22 months. 7 of the 11 children housed in that room had diarrhoea between July 11 and July 22, 1982. All 7 shed adenoviruses detectable by electron microscopy in their stools. Immune electron microscopy showed that all patients as well as the healthy contacts sharing the room underwent seroconversion to EAd. There was no homology, or very slight homology, between DNA of EAd and those of adenoviruses belonging to subgroups A to E. Antigenically EAd was closely related to type 40 adenovirus, so far the sole member of the newly identified subgroup F. This outbreak of gastroenteritis is the first in which the causative agent has been identified as being a member of subgroup F adenoviruses.

Adenoviridae Infections↗
PubMed1983

Electrostatic and hydrophobic effects in chromatography of rabbit IgG immunoglobulins on aminohexyl sepharose substituted with bis-(p-chlorophenyl)- acetic acid.

The binding interactions of rabbit IgG immunoglobulins with bis-(p-chlorophenyl)-acetic acid (DDA) substituted aminohexyl Sepharose (AHS) (DDA-AHS) at low ionic strength are under the influence of pH, temp, ionic strength and their antibody specificity. The IgG molecules held on a DDA-AHS column in the presence of 0.01 M phosphate buffer (pH 6.8) at 4 degrees C could be stepwise eluted by the addition of 0.01 M acetate buffers (pH 5.5, 5.0 and 4.5) followed by 3 M NaClO4, a chaotropic reagent. The adsorbability of IgG molecules by the DDA-AHS column was reinforced at temps higher than 4 degrees C and at increasing NaCl concns ranging from 0.05 to 0.2 M. The antibody specificity and, perhaps, binding affinity greatly affected this binding system. On the basis of these results, it was evident that both the DDA ligand and charged groups (omega-amino and isourea groups) took part in the binding interactions between IgG molecules and the agarose derivative at low ionic strength. Thus the binding interactions of rabbit IgG immunoglobulins with DDA-AHS at low ionic strength are assumed to be due to hydrophobic plus electrostatic interactions. It was also observed that the binding site on the surface of IgG molecules at low ionic strength was located only in the Fab region.

Animals↗
PubMed1983

Monoclonal antibodies reactive with different sites of N and H antigenic particles of poliovirus.

We established three hybridomas (designated 2A12, 4C4 and 6H8) secreting monoclonal antibodies which react with N and H(heated) antigenic particles of poliovirus type 1 (Mahoney strain). One of these monoclonal antibodies, 4C4, had virus-neutralizing activity, while the other two were non-neutralizing. A solid-phase radioimmunoassay and a neutralization test indicated that the specificity of the neutralizing monoclonal antibody 4C4 was the same as that of the monospecific antibody HN31, previously prepared by us by absorbing poliovirus antiserum with an equine serum inhibitor-resistant mutant (M-HN31) of poliovirus. Furthermore, by means of immune electron microscopy, it was revealed that the combining site of the 4C4 neutralizing monoclonal antibody is on or around vertices of the N and H antigenic particles, while the other two monoclonal antibodies are directed to the entire surface of the antigens.

Antibodies, Monoclonal↗
PubMed1983

Isolation of virus causing hemorrhagic fever with renal syndrome (HFRS) through a cell culture system.

Twenty-three rat lung specimens collected in outbreaks of hemorrhagic fever with renal syndrome (HFRS) in three medical institutions were inoculated onto the VERO-E6 cell monolayers. After several blind passages, an agent growing serially in the cell cultures and reacting specifically with known HFRS-positive sera was isolated from two of these specimens. The two isolates were antigenically identical each other. The agent, named strain SR-11, was identified as the causative virus of HFRS by its antigenic identity with E6 cell-adapted HFRS virus, Hantaan 76-118 strain, and the specific reactions with sera from various HFRS cases.

Adolescent↗
PubMed1982

Chromatographic analysis of the hydrophobic interactions of rabbit IgG immunoglobulins and their papain-digested fragments by bis-(p-chlorophenyl)-acetic acid coupled to aminohexyl sepharose.

The present study revealed that the IgG immunoglobulins of normal or non-immune rabbit IgG and anti-bovine serum albumin, anti-ovalbumin, anti-bovine IgG and anti-p-chlorobenzoic acid antibodies could non-specifically bind to bis-(p-chlorophenyl)-acetic acid (DDA) coupled to omega-amino-hexyl Sepharose (AHS) by the use of strengthened hydrophobic interactions dependent on the concentration of NaCl. The main binding site on the adsorbent of DDA-substituted AHS (DDA-AHS) was found to be the DDA ligand. The hydrophobic potency of the DDA ligand was thought to be more effective than that of p-chlorobenzoic acid coupled to AHS. Out study also demonstrated that two different binding sites capable of interacting the DDA ligand were contained in IgG molecules. One was located in the Fc region and the other in the Fab region. The former had an ability to adhere to the DDA-AHS adsorbent in the presence of NaCl of 3 M or over, while the latter showed heterogeneous binding behavior depending upon its antibody specificity. Differences in the chromatographic distribution among the whole IgG immunoglobulins including anti-DDA antibody were found by a hydrophobic salting-out chromatography (HSOC) method on a DDA-AHS column. It was therefore assumed that when whole IgG proteins were subjected to HSOC on a DDA-AHS column, the hydrophobic binding site in the Fc region played a decisive role at high salt concentrations of 3 M or over, while the hydrophobic binding site in the Fab region played a major role at intermediate and low salt concentrations of 2 M or below. Thus, by taking advantage of this HSOC method, whole IgG or its Fab molecules possessing very strongly hydrophobic binding sites to promote high quantum yields of 8-anilinonaphthalene-1-sulfonate (ANS) fluorescence can be easily separated. We concluded that the ligand of DDA is a probe for the hydrophobic regions in IgG immunoglobulins.

Anilino Naphthalenesulfonates↗
PubMed1982

Genotoxicity of flavoring agents.

The genotoxicity of 9 flavoring agents widely used in everyday foods was studied by a bacterial mutation test in the Salmonella/microsome system and by a chromosome test in Chinese hamster (CH) cells. In the mutation test none of the flavorings exhibited significant induction of his+ revertants in Salmonella typhimurium TA98 or TA100, either with or without rat-liver microsome as the metabolic activation system. On the other hand, in the chromosome test most of the agents induced severe chromosome aberration in the treated CH cells, suggesting a potential genotoxicity.

Animals↗
PubMed1982

Electrophoretic analysis of RNA segments of human rotaviruses cultivated in cell culture.

Human rotaviruses (HRVs) derived from stools were cultivated to high titres in an established cell line (MA-104) using the rotary culture system. Analysis of the 11 double-stranded RNA segments of the culture-adapted HRVs was carried out by polyacrylamide gel electrophoresis. Tissue culture-adapted HRVs, uncloned or cloned, had the same RNA gel patterns as those of the original HRVs from the individual stool specimens. The migrations of the RNA segments from the culture-adapted HRVs were markedly different from that of the RNA segments from calf rotavirus (Lincoln strain). Considerable heterogeneity in electrophoretic migration of the RNA was found among eight strains of the HRVs grown in cell culture. These results confirmed that viruses isolated from stool specimens were indeed of human origin and were not the result of laboratory contamination with tissue culture-adapted calf rotavirus or other viruses.

Adolescent↗
PubMed1982

Three human rotavirus serotypes demonstrated by plaque neutralization of isolated strains.

Human rotaviruses were isolated directly from stool specimens of gastroenteritis patients in MA-104 cells in the presence of trypsin. For the plaque assay of the isolated strains, the optimal composition of overlay medium was determined. The antigenicity of the isolated strains was investigated by a plaque neutralization method, using antisera prepared against six strains having different electropherotypes of viral RNA, and three different neutralization serotypes were demonstrated.

Antigens, Viral↗
PubMed1981

Further studies of 35--40 nm virus-like particles associated with outbreaks of acute gastroenteritis.

Virus-like particles similar in size and morphology to the Otofuke agent, which was detected first in an institutional outbreak of acute gastroenteritis at Otofuke, Hokkaido, Japan in 1978, were again observed in faeces from patients in four other outbreaks of acute gastroenteritis in Hokkaido. In each of three outbreaks in which the faeces and paired sera of patients were available, apparent sero-responses against the particles obtained in corresponding outbreaks were confirmed. Serological analysis of the particles from five separate epidemics by immune electronmicroscopy suggested that the particles from these epidemics may be related antigenically to one another. Besides the above-mentioned particles measuring 35--40 nm in diameter, 15--20-nm "empty" particles were also found in the stool specimens obtained from two of the five epidemics. In addition, serological cross reactivity between these two kinds of particles was observed. These findings provide further support for the aetiological role of the 35--40-nm particles (Otofuke agent-like particles) in acute gastroenteritis in older children and adults.

Acute Disease↗
PubMed1981

Sequential passages of human rotavirus in MA-104 cells.

Starting with a small amount of diarrheal feces containing human rotavirus (HRV), we succeeded in propagation of the virus using the roller culture technique with MA-104 cells. Furthermore, we made a successful adaptation of HRV to a stationary culture and developed a plaque assay for the cell culture-adapted viruses. The 3 culture-adapted virus isolates, KU, YO, and 44 produced plaques (about 0.5-1.0 mm in diameter) under the overlay medium consisting of 0.6% purified agar, 3 micrograms of acetyl trypsin/ml and 50 micrograms of DEAE-dextran/ml. Subsequent plaque purification resulted in the formation of clear, larger plaques. It was shown from the results of cross neutralization tests using the fluorescent focus reduction method that the three culture-adapted HRV isolates were clearly different antigenically from ovine rotavirus (NCDV) and, further, that a noticeable difference in antigenicity also existed among the HRV isolates.

Animals↗
PubMed1981

A survey of rotavirus infection in the topics.

The age distribution of rotavirus antibody in the serum of inhabitants of Laos and Indonesia was studied by the neutralization test using antigenically related calf rotavirus (NCDV) as a substitute for non-cultivable human rotavirus. The results revealed that both the rate of antibody-positives and the modal titers of antibody distribution by each age group in these countries were higher than those in respective are groups of Japanese, which suggest higher endemicity of rotavirus infection in these countries. A survey of rotavirus in diarrheic patients' stools by enzyme-linked immunosorbent assay indicated that the virus infection occurred most frequently among infants between 4 and 12 months of age.

Adolescent↗
PubMed1979

Reactivity of neutralizing antibodies with different specificities to H particles of poliovirus.

In order to elucidate the antigenic structure of poliovirus, the reactivity of antibody produced with H antigenic particles of Mahoney strain (polio type 1) was investigated. Injection of H particles of Mahoney strain into rabbits yielded neutralizing antibody as well as CF-N and CF-H antibodies. This result coincided with the report by Hinuma and coworkers. Neutralization tests with inhibitor resistant Mahoney mutants revealed that the neutralizing antibody produced with H particles was of HN31 type, one of the five different kinds of polio neutralizing antibodies reported previously (14). Absorption experiments with H particles on different neutralizing antibodies and analysis of antibody eluted by acid dissociation from antiserum-treated H particles also showed that the HN31 type antibody specifically combined with H particles of Mahoney strain. Since the H particle of poliovirus is known to be deficient in VP4, these results seems to indicate that the HN31 type antibody reacts with a structural part(s) of poliovirus other than VP4.

Absorption↗