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T Osato

Publications and source records attributed to T Osato.

At least 55 records · Page 3Linked to original sources
PubMed1991

Mass spectrometric identification of a phorbol diester 12-O-hexadecanoylphorbol-13-acetate, an Epstein-Barr virus-activating substance, in the soil collected from under Sapium sebiferum.

Soil-extracts collected from the ground from under several Euphorbiaceae plants have been known to possess Epstein-Barr virus (EBV)-activating substances which are thought to be one of the environmental co-factors causing nasopharyngeal carcinoma (NPC) in southern part of China and Burkitt's lymphoma (BL) in tropical Africa. Then, a model experiment aimed at chemical characterization of such active substances was carried out using a soil-extract around Sapium sebiferum, a Japanese representative Euphorbiaceae plant. Chromatographic separation guided by the EBV early antigen (EA) inducing activity gave a highly active fraction. Application of this fraction to desorption chemical ionization mass spectrometry identified a major active substance to be 12-O-hexadecanoylphorbol-13-acetate (HPA), which originally occurs in this plant. The method in this model experiment is suggested to be applicable to other samples from the endemic areas of NPC and BL.

Herpesvirus 4, Human↗
PubMed1991

Kawasaki disease and Epstein-Barr virus.

We report the results of virological (serological and molecular biological) studies of Epstein-Barr virus (EBV) in patients with Kawasaki disease (KD). Forty-nine (86%) of 57 Kawasaki disease patients and 15 (68%) of 22 patients with recurrent Kawasaki disease had serological evidence of primary Epstein-Barr virus infection during the first month after the onset of their disease based on the results of a sensitive method of detecting antibody to viral capsid antigen (VCA). The serological response to EBV was significantly low and transient. EBV sequences were identified directly in peripheral blood mononuclear cell (PBMC) DNA samples from 23 (56%) of 41 KD patients within 2 weeks after onset by means of the polymerase chain reaction (PCR). EBV sequences were also detected in 10 (83%) of 12 repeatedly tested KD patients within 3 months after onset. In contrast, only 7 (18%) of 40 control DNA samples were PCR-positive. These virological studies indicate that an unusual EBV-cell interaction may occur in KD.

Antibodies, Viral↗
PubMed1991

Severe chronic active Epstein-Barr virus infection syndrome.

Reports of unusually severe lymphoproliferative disorders associated with extremely high antibody titers against Epstein-Barr virus (EBV) have recently increased. The syndrome, which we designated severe chronic active EBV infection syndrome, is characterized by persistent or intermittent fever, lymphadenopathy, and hepatosplenomegaly and primarily affects children and young adults. Polyclonal gammopathy and bone marrow suppression are generally observed, and some patients develop B-cell or T-cell lymphoproliferation or lymphoma. Frequently, EBV genomes are detectable in tissues infiltrated with lymphoid cells. Additionally, it is difficult to establish spontaneous or B95-8 EBV-induced cell lines despite the expression of an activated EBV infection. We review and report here the published medical literature and our own experience regarding patients with severe chronic active EBV infection syndrome in an attempt to understand this enigmatic syndrome and the possible pathogenetic mechanism(s) responsible for this disorder.

Chronic Disease↗
PubMed1990

Epstein-Barr virus in nasal T-cell lymphomas in patients with lethal midline granuloma.

Five cases of lethal midline granuloma were identified histologically and phenotypically as peripheral T-cell lymphomas. Epstein-Barr virus (EBV) DNA was detected in the nasal tumour biopsy specimens by Southern blotting and in-vitro hybridisation with simultaneous detection of EBV-determined nuclear antigen (EBNA) and T-cell surface markers by two-colour immunofluorescence. Further immunofluorescence and northern blotting revealed that EBNA2 gene and also latent membrane protein gene were expressed in the nasal tumour cells. The patients had high titres of antibodies to EBV. These findings suggest that lethal midline granuloma is causally associated with EBV.

Adult↗
PubMed1990

[A senile case of B-cell lymphoma with high titers of an EB virus-associated antibodies].

An 83-year-old man suffering from general malaise and discomfort in the epigastrium was admitted to hospital. On testing, peripheral blood and bone marrow smears disclosed a number of abnormal lymphocytoid cells, and a CT and a linear echo scan revealed splenomegaly and a multiple intraperitoneal lymphadenopathy, although no superficial lymph nodes were palpable. Further, abnormal lymphocytoid cells were positive for B1, B4, OKIa1, Leu1, Tac, anti-IgM, anti-IgD, and anti-lambda. Thus, a diagnosis of malignant lymphoma of the intermediate B-cell type was made. Surprisingly, serological examination reveared extremely high titers of EB-virus associated antibodies (VCAIgG 20, 480x, VCAIgA 320x, EAIgG 2,560x), but no EBNA or virus particles were detected in the tumor cells, so that no direct relationship was established between the development of the tumor and the EBV infection.

Aged↗
PubMed1989

Sites of Epstein-Barr virus replication in acute and chronic active Epstein-Barr virus infections.

We examined Epstein-Barr virus (EBV) in saliva samples and peripheral blood mononuclear cells (PBMC) from 9 patients with acute infectious mononucleosis (IM) and 4 patients with chronic active EBV infection (CEBV). All saliva samples from patients with acute IM were positive for EBV by both Southern blot hybridization assay and the cord transformation assay. In contrast, EBV DNA could not be detected in saliva samples from patients with CEBV. Only one of the saliva samples from 4 patients with CEBV could transform cord blood lymphocytes with extreme difficulty. No saliva samples from patients with CEBV were capable of inducing early antigens in Raji cells. On the other hand, EBV DNA was detected in PBMC from 3 of the 4 patients with CEBV but not in those from patients with acute IM by Southern blot hybridization. Spontaneous lymphoblastoid cell lines could be easily established from PBMC of patients with acute IM but not from PBMC of patients with CEBV, despite several attempts. Viral capsid antigen and early antigens were not observed in cultured cells from patients with CEBV. These results suggest that the main site of EBV replication in CEBV might not be oropharyngeal epithelial cells.

Adult↗
PubMed1988

Flow cytometric analysis of Epstein-Barr virus receptor among the different B-cell subpopulations using simultaneous two-color immunofluorescence.

The distribution of Epstein-Barr virus receptor (EBVR) among the different B-cell subpopulations was analyzed by flow cytometry, using simultaneous two-color immunofluorescence of EBVR and cell-surface markers. The expression of EBVR was established by the binding of fluorescein isothiocyanate (FITC)-labeled EBV to the cells, while surface markers were stained by phycoerythrin (PE)-indirect immunofluorescence, using monoclonal antibodies. All cells of both the resting B-cell subpopulation defined by L30 and the B-cell subpopulations expressing surface IgM, IgD, IgA, and IgG were EBVR-positive. In contrast, EBVR was absent from about 10% cells of the activated B-cell subpopulation recognized by OKT9, as well as from about 10% cells of the highly differentiated B-cell subpopulation which reacted with OKT10. These results suggest that the expression of EBVR on the B-cell lineage varies with the maturation stage and with the state of activation. This postulation was further supported by analyses based on in vitro B-cell activation.

B-Lymphocytes↗
PubMed1988

Establishment and characterization of an Epstein-Barr virus negative B-cell lymphoma cell line and successful heterotransplantation.

An EBV-negative B-cell lymphoma cell line designated as HBL-1 was established from the pleural effusion of a patient with malignant lymphoma, diffuse, large cell. Surface marker studies revealed that HBL-1 cell possessed the same phenotypes of a mature B-cell as the original lymphoma cell from pleural effusion. HBL-1 closely resembled morphologically to the original lymphoma cells observed in the lymph node biopsy and pleural effusion. Chromosome analysis revealed that HBL-1 cells showed chromosomal aberrations of a 14q+ marker chromosome as the result of a translocation between chromosomes 14 and 16. Heterotransplantation to subcutaneous tissue of an athymic nude mouse has succeeded, but intraperitoneal heterotransplantation has failed. Tumors were localized in the subcutaneous tissues and no metastasis was found. This newly established cell line may facilitate immunological and oncogenic studies for human B-cell lymphomas.

Aged↗