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Biomedical subjects

S Urasawa

Publications and source records attributed to S Urasawa.

At least 145 records · Page 8Linked to original sources
PubMed1979

Virus-like particle, 35 to 40 nm, associated with an institutional outbreak of acute gastroenteritis in adults.

In an outbreak of acute gastroenteritis in an institution for the mentally retarded at Otofuke, Hokkaido, Japan, virus-like particles were observed by electron microscopy in five of seven stool specimens from the patients. The particles had 10 rod-shaped and 10 round projections or capsomeres on the periphery, measured 35 to 40 nm in diameter, and had a buoyant density of 1.35 to 1.37 g/ml in cesium chloride. Attempts to culture these particles in tissue culture or in mouse brain were unsuccessful. Immune electron miscroscopy performed with the virus from the patients as antigen demonstrated significant serological responses in all patients examined. Antigenic similarity of the virus particles obtained from five patients was also confirmed by immune electron microscopy with the paired acute- and convalescent-phase sera of one of the patients. Furthermore, in immune electron micrsocopy these particles appeared to have no antigenic relationship to three candidate viruses for gastroenteritis so far reported: the Norwalk agent, the W agent, and the calicivirus-like particle. These results suggested the possibility that this agent, tentatively designated as the Otofuke agent, might be a new candidate virus for gastroenteritis.

Acute Disease↗
PubMed1979

Geographic distribution of arbovirus antibodies in indigenous human populations in the Indo-Australian archipelago.

Sera from lifetime residents in 16 localities of the Indo-Australian archipelago and adjacent areas were tested for hemagglutination-inhibition antibody against four alpha-viruses (Sindbis, Getah, chikungunya, and Ross River) and for neutralizing antibody against six flaviviruses (dengue 2 and 3, Japanese encephalitis, Murray Valley encephalitis, Kunjin, and Edge Hill). Mosquito collections were carried out in some of the localities to study vector relationships to distribution of the arbovirus antibodies. Antibodies specific to Sindbis and Getah viruses were rare except in north Australia. Chikungunya virus-specific antibody was highly prevalent in localities of the Oriental zoogeographic region and Wallacea, rare in west New Guinea, and absent in north Australia. Age distribution of chikungunya antibody suggested that the antibody last occurred in most Indonesian localities about 30 years ago. Ross River virus-specific antibody was confined to localities of the Australian zoogeographic region. Antibodies reacting to dengue 2 and 3 viruses occurred in high frequency in the entire area of the archipelago. Antibodies specific to Murray Valley encephalitis and Kunjin viruses were also widespread although at a very low frequency. Japanese encephalitis virus-specific antibody was highly prevalent in areas west of Wallace's Line while it was absent in areas east of the line with the exception of Lombok. Antibody to Edge Hill virus was rare and confined to the Australian zoogeographic region. The distribution of arthropod vectors, vertebrate hosts, and of arboviruses are discussed in relation to zoogeographic divisions.

Age Factors↗
PubMed1979

An out-break of acute gastroenteritis due to rotavirus in an infant home.

In December 1976, an outbreak of acute infectious diarrhea occurred among infants who resided in an infant home in the city of Sapporo. Rotavirus infection was proved in 42 (90%) of 47 infants by serologic and/or electron microscopic examinations. Out of 42 infected infants 38(90%) were clinically affected; diarrhea with or without vomiting in 27 (64%), vomiting without diarrhea in 6 (14%) and only febrile episode in 5 (12%). The remaining 4(10%) infants showed no symptoms. Clinical manifestations seemed to differ depending on age. Diarrhea without vomiting was more common in the patients younger than 6 months of age, and vomiting or fever was more common in the groups of older age. Possible reasons for such an age dependency were discussed on the basis of complement-fixation tests using human and calf strains of rotavirus.

Acute Disease↗
PubMed1978

Demonstration of antibodies to chlorophenothiazine derivatives.

Antibody to 2-chloro-10-(2-carboxyethyl)-phenothiazine (CECP) was produced in rabbits by immunization with the hapten-BSA conjugate. The titer of antibody was determined by passive hemagglutination (PHA) using erythrocytes coupled with the CECP-protein carrier. Results from inhibition tests using structurally related (CECP, CPZ, PCPZ, CMP) and almost unrelated haptens (DDA, RF) strongly suggested that both the side chain and the nucleus of the haptens are important in determining the specificicity of immunological reactions. 18 sera from psychiatric patients administered phenothiazine derivatives for a long time as well as 20 control sera from healthy individuals were then tested for their reactivity to CECP. Of patients' sera, 12 had detecable hemagglutination titers (1:8 or greater), while all of the normal human sera were negative. The PHA activity was contained in euglobulin fraction and was specific in the inhibition tests. From these results, the activity to CECP in patients' sera was supposed to be specific antibody.

Animals↗
PubMed1977

Antigenic variation of poliovirus caused by antibody components with different specificities.

The possible role of antibody as a selective pressure on antigenic mutants of poliovirus in nature was investigated in vitro. A mutant resistant to a monospecific antibody with a definite specificity was readily obtained by several cycles of neutralization of Mahoney strain with a monospecific antibody and multiplication in monkey kidney (MS) cells. Mutants resistant to more than two different monospecific antibodies were also readily obtained in a similar manner. Studies on the antigenicity of these mutants by kinetic neutralization tests revealed that the Mahoney strain underwent a progressive serological variation as it became successively resistant to one to five different monospecific antibodies isolated from anti-Mahoney serum.

Antibodies, Viral↗
PubMed1976

Further studies of specificity of antibodies contained in antiserum against poliovirus.

Antigenic components of Mahoney strain (poliovirus type 1) involved in virus neutralization reaction were analyzed with mutant Mahoney strains resistant to inhibitors in equine serum (inhibitor-resistant mutants) by means of the kinetic neutralization test. It was shown that absorption of anti-Mahoney serum with five inhibitor-resistant mutants yielded sera with different antibodies, of which three had distinct specificities and two specificities possibly partly related to one of those three sera. Further, it was found that step wise selection of Mahoney variants resistant to one, two, three and four different inhibitors resulted in gradual deviation of its antigenic composition from that of the original strain. From these results, the possible presence of three or more distinct antigenic determinant sites on the surface of Mahoney strain was indicated.

Antibodies, Viral↗