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Biomedical subjects

T Kurata

Publications and source records attributed to T Kurata.

At least 307 records · Page 17Linked to original sources
PubMed1988

Molecular genetic approaches to the pathogenesis of bacillary dysentery.

Bacillary dysentery is an invasive infectious disease of the human colon. At least three genetic loci on the chromosome and a huge plasmid have been implicated in its pathogenesis. Results obtained from molecular genetic studies, mainly of the genes, virG, virF and kcpA are discussed.

Animals↗
PubMed1987

Genome variation among varicella-zoster virus isolates derived from different individuals and from the same individuals.

We have used 12 restriction enzymes to analyse the DNA of 24 clinical isolates of VZV derived from 12 patients in order to compare isolates derived from different individuals and derived serially from the same individual. As reported previously, only a small proportion of the isolates differed with respect to the presence or absence of restriction sites. However, we found that the size of DNA fragments generated from all the isolates derived from different patients varied in any of four regions, one of which was first recognized in this study. In one case, where multiple isolates recovered from the same individual were analysed, each was distinguished from the others not only by differences in the variable regions but also by the presence or absence of a restriction site in a nonvariable region. This suggests that multiple strains of VZV can be present in the same human host.

Chickenpox↗
PubMed1987

Role of T lymphocyte subsets in protection and recovery from Hantaan virus infection in mice.

Adult athymic nude (BALB/c background) mice or inbred BALB/c mice were inoculated intraperitoneally with Hantaan virus (HV), and attempts were made to isolate the virus from brain, lung and spleen. Virus was isolated from the organs of BALB/c mice for only a short time after infection but was isolated from various organs of nude mice consistently for at least 84 days after infection. Viral antigen was also detected in various organs of nude mice for a long time after infection. The effects of adoptive transfer of immune serum or immune T cells from BALB/c to nude mice before or after virus inoculation were examined. Before transfer, the T cell fraction was treated with complement (C') (group 1), anti-L3T4 + C' (group 2), anti-Lyt1.2 + C' (group 3) or anti-Lyt2.2 + C' (group 4). When transferred before virus inoculation to test the effects on protection against infection, immune serum and T cells of groups 1, 2 and 4 were effective. When transferred after HV inoculation to test the effects on clearance of virus, group 1 was the most effective followed by group 2. These results suggest that humoral and cellular immunity both have roles in protection against HV infection, and that T cells possessing L3T4- Lyt2+ markers on the cell-surface are especially important for elimination of infectious virus in vivo.

Animals↗
PubMed1987

Acute pancreatitis with cytomegalovirus infection.

An autopsy case of necrotizing pancreatitis with cytomegalovirus (CMV) infection is reported. A 50-year-old housewife was admitted because of malignant choroid plexus papilloma of the fourth ventricle. Serum amylase transiently elevated during irradiation and chemotherapy for brain tumor, one month before death. The patient died of a respiratory failure. At autopsy focal necrosis was mainly observed in the peripancreatic adipose tissue and occasionally in the parenchyma of the tail. Fibrosis and inflammatory infiltration was found around the necrosis and interstitium. Cytomegalic cells with intranuclear inclusions and/or cytoplasmic granules were observed frequently in the acini near the necrosis. Immunohistological study revealed CMV antigen in the cytomegalic cells. Herpesvirus-type particles were observed in the nucleus and cytoplasm of the cytomegalic cells. CMV infection of the acini are thought to cause necrotic changes in the pancreas.

Acute Disease↗
PubMed1987

Viruses of hemorrhagic fever with renal syndrome (HFRS) grouped by immunoprecipitation and hemagglutination inhibition.

Nine viruses antigenically related to Hantaan virus that were isolated from various rodents in several countries and from a patient were examined by immunoprecipitation and by hemagglutination inhibition (HI). The immunoprecipitation tests were done with a monoclonal antibody that reacted with glycoprotein G2 and an antibody against a nucleocapsid protein. The viruses were classified into four subtypes on the basis of the molecular weights of their precipitated polypeptides and the pattern of results of the HI tests.

Animals↗
PubMed1987

Erythorbic acid content in tissues of guinea pigs administered erythorbic acid.

The erythorbic acid (ErA) content in the tissues of guinea pigs administered ErA was compared with that of ascorbic acid (AsA). Guinea pigs were administered 1, 5, 20, and 100 mg ErA/day or 1, 5, and 100 mg AsA/day for 16 days and then sacrificed. The liver, adrenal glands, spleen, and kidneys were removed to determine the contents of ErA and AsA using HPLC. Only a small amount of ErA was found in four tissues of the animals administered 20 mg or more of ErA/day. On the contrary, AsA was found in the tissues of all animals administered 1 mg or more of AsA/day. The ErA content in the tissues was much lower than that of AsA even when the amount of ErA administered was the same as that of AsA. However, the body weight gains of animals administered ErA were similar to those of animals administered AsA. These observations suggested that the mechanism of the retention of ErA in the tissues was much different from that of AsA and that the vitamin C activity of ErA might be more than one-twentieth that of AsA.

Adrenal Glands↗
PubMed1987

Detection of varicella-zoster virus DNA in cultured cells and tissue specimens by in situ hybridization using biotin-labeled probes.

A method of in situ hybridization with biotinylated probes is described for specific detection of varicella-zoster virus (VZV) DNA in infected cell cultures and in human biopsied or autopsied materials. From molecularly cloned EcoRI-fragments of VZV DNA, we selected as probes for in situ hybridization three fragments (B, H, and K) which had any detectable homology neither with human cell DNA nor with DNAs of VZV-related viruses (herpes simplex virus type 1, type 2 and human cytomegalovirus). The procedure of in situ hybridization was based on that of Brigati et al. (Virology 126, 32-50, 1983), but following modifications were made. 1) The concentration of probe DNA was lowered to 100 ng per ml. 2) Streptavidin-biotin system was used for detection of hybridization. 3) Acid phosphatase was used to generate color development discernible from melanin present in skin. 4) Before hybridization, deparaffinized sections were treated with trypsin by the procedure routinely employed for detection of viral antigens in paraffin-embedded sections.

Cells, Cultured↗
PubMed1987

Control of laboratory acquired hemorrhagic fever with renal syndrome (HFRS) in Japan.

By the end of 1985, 126 human cases of laboratory acquired hemorrhagic fever with renal syndrome (HFRS) were recorded in Japan. Seroepidemiological studies revealed that laboratory rats exhibited high IFA titers against Hantaan or related viruses at locations where HFRS patients occurred. Laboratory researchers contracted HFRS more frequently than laboratory animal technicians or caretakers, although a laboratory animal caretaker died of the disease. Inhalation of HFRS-virus contaminated air in an animal facility is the likely cause of infection with this virus. Wound infection during animal experiments may be another important route of infection. Infection of laboratory rats can occur by transferring animals from contaminated to other animal facilities. Tissue fragments or cells of transplantable animal tumors are a potential source of spreading the HFRS virus. Eradication of HFRS virus from a contaminated animal facility can be achieved best by elimination of all animals in the room, especially when human HFRS is associated with an infected colony. In some cases, when IFA titers of the sera of the rats tested were low, infection apparently disappeared without instituting any particular control measures other than ordinary procedures for care and management of laboratory animals. HFRS viruses have not yet been eradicated from all animal facilities in Japan. Therefore, serological monitoring of laboratory rats continues.

Animals↗
PubMed1986

A genetic determinant required for continuous reinfection of adjacent cells on large plasmid in S. flexneri 2a.

We have identified a region (virG) on the 230 kb virulence plasmid of S. flexneri that is required for cell-to-cell spread of the bacterium. Tn5 insertions into this region result in avirulent mutants that can initially invade and multiply in epithelial cells, but tend to lose active movement and tend to localize within the cytoplasm, where they are gradually extinguished without infecting adjacent cells. The virG region was localized to within 4 kb and may contain a single cistron. Sequences hybridizing to this region were found in all intact virulence plasmids of Shigellae and enteroinvasive E. coli.

Animals↗
PubMed1986

Analysis of viral antigens in giant cells of measles pneumonia by immunoperoxidase method.

The localization of measles virus proteins was analyzed by immunoperoxidase method using both monospecific and monoclonal antibodies. In Vero cells infected with the Edmonston or EB-L strain, the former being a laboratory strain and the latter a fresh isolate from a measles patient, nucleocapsid protein was located in the nuclei, and matrix protein, phosphoprotein, haemagglutinin and fusion protein were located in the cytoplasm. In the lung tissues of eight cases with measles giant cell pneumonia, the similar findings were obtained. The presence of haemagglutinin on the surface of giant cells at the luminal side was also noticed. Histopathologically, measles giant cells had nuclear and cytoplasmic eosinophilic inclusion bodies with some differences in appearance. The significance of localization of viral proteins is discussed in comparison with histopathological findings in measles giant cells.

Antibodies, Monoclonal↗
PubMed1986

Characterization of glycoproteins of viruses causing hemorrhagic fever with renal syndrome (HFRS) using monoclonal antibodies.

Viruses causing hemorrhagic fever with renal syndrome (HFRS) encode two glycoproteins, G1 and G2. For determination of the biological functions of these glycoproteins, we isolated 15 hybridomas secreting monoclonal antibodies directed against the glycoproteins of the B-1 and Hantaan viruses (HV). From results of neutralizing and hemagglutination inhibition (HI) tests, and studies on the antigenic reactivities of the antibodies with other HV-related viruses by immunofluorescence, we classified these hybridoma clones into two groups producing antibodies to the G1 proteins of the B-1 virus, six groups producing antibodies to G2 proteins of the B-1 virus, and four groups producing antibodies to the G2 protein of HV. Of the antibodies to G2 produced by 12 clones, groups A and B had high HI activity with HV-related virus cross-reactivity and moderate neutralizing activity, group C had moderate HI activity with virus specificity but low neutralizing activity, group G had high neutralizing activity and low HI activity, and five other groups had little or no HI or neutralizing activity. Group A reacting with G1 protein had low level of both neutralizing and HI activity, while group B had no HI activity. One clone of monoclonal antibody had high neutralizing activity and no HI activity, but it did not react with either polypeptide by immunoprecipitation followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis or by the immunoblotting method. These data suggest that both glycoproteins are the targets of neutralizing antibodies. Furthermore, the results indicate that the antigenic determinants with hemagglutination activity are mainly on the G2 protein, and that the domains related to neutralizing activity and to HI activity are separate.

Animals↗
PubMed1986

Persistent infection of rats with haemorrhagic fever with renal syndrome virus and their antibody responses.

Newborn (within 24 h after birth), 1-week-old and 6-week-old (adult) rats were inoculated with a Hantaan-related virus (B-1) and attempts were made to isolate the virus from various organs. Virus-specific antigens were detected in various organs of newborn rats. Moreover virus could be isolated from almost all their organs even 25 weeks after infection. In contrast, in rats infected at 6 weeks of age the virus could be isolated from various organs but its concentration decreased progressively with time. The levels of haemagglutination-inhibiting (HI) and neutralizing antibodies to B-1 virus in the sera were measured. In adult rats, HI antibodies were first detected 2 weeks after infection and their titre rose to a maximum after 5 weeks. On the other hand, in newborn rats the levels of antibodies remained low until 5 or 6 weeks after infection and started to increase to a high level more than 9 weeks after infection. Furthermore, in rats infected soon after birth IgM antibodies predominated for a long time and these antibodies also neutralized infectivity at a high level. These data suggest that the induction of a high titre of neutralizing antibodies mainly of the IgM type does not result in virus clearance in newborn rats and that cellular immunity may be important for virus clearance in vivo.

Aging↗
PubMed1986

Activation of cytomegalovirus infection in immunosuppressed cynomolgus monkeys inoculated with varicella-zoster virus.

A systemic activated cytomegalovirus (CMV) infection was fortuitously detected in almost all monkeys which had been immunosuppressed with antithymocyte globulin (ATG), cyclophosphamide (CY), and cortisone acetate (CS) before and after experimental inoculation with varicella-zoster virus (VZV). They developed exudative pneumonia, and the lesions in visceral organs and tissues contained cytomegalic cells with intranuclear inclusion bodies, in which viral antigens, specific for CMV, but not inoculated VZV, were detected by immunofluorescence. Serological study of paired sera from these monkeys ascertained preexisting CMV infection. Under the present experimental conditions, this infection was highly reproducible and always occurred within three, but not two, weeks of immunosuppression in monkeys inoculated with VZV. We therefore examined the host factors involved in activation of latent CMV. The immunocompetence of the host was destroyed almost completely with treatment of ATG, CY, and CS, but not with combinations of two of these agents, revealing the systemic depletion of lymphoid cells in tissues including the thymus medulla. Although the role of VZV in the induction of CMV remains uncertain, the heterologous VZV inoculum may have produced some effects equivalent to the allogeneic reaction to release latent CMV. These monkeys may represent an animal model of "opportunistic" CMV infection in immunocompromised and/or allografted humans.

Age Factors↗
PubMed1986

Peanut agglutinin receptor is a marker of myelin in rat brain. Developmental changes in its distribution.

Peanut agglutinin receptor, which is a glycoconjugate with terminal Gal(beta 1-3)GalNAc residues, was found to be a specific biochemical marker of the myelin in rat brain. The localization of peanut agglutinin receptor in rat brain was studied by use of fluorescein-conjugated peanut agglutinin. In adult rat brain, receptors were found only on myelin. In contrast, the receptors in fetal brain were not found in the white matter, but only in the ependyma. Peanut agglutinin receptors were extracted from adult and fetal rat brains with 2% Triton X-100, subjected to electrophoresis on 10% sodium dodecyl sulfate-polyacrylamide gel, blotted onto nitrocellulose filters, and detected by their reaction with peroxidase-conjugated peanut agglutinin. A major receptor of Mr 130,000 and a minor one of Mr 200,000 were found in both adult and fetal rat brains.

Age Factors↗