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S Ohga

Publications and source records attributed to S Ohga.

106 records · Page 6Linked to original sources
PubMed1990

Augmentation of host defense against bacterial infection pretreated intraperitoneally with an alpha-glucan RBS in mice.

Protection against Listeria monocytogenes and Escherichia coli in mice was enhanced by an intraperitoneal (i.p.) administration of polysaccharide "RBS". Peritoneal macrophages from mice administered i.p. with 30 mg/kg doses of RBS 4 days earlier exhibited increased scavenger functions as assessed by in vivo phagocytosis, in vitro intracellular killing and generation of superoxide anion. When cytokine production of the macrophages was assessed by biological assay and Northern blotting analysis, interleukin (IL)-1 production and IL-1 alpha gene expression were significantly increased in macrophages from RBS-treated mice. On the other hand, tumor necrosis factor (TNF) alpha gene was expressed in macrophages from RBS-treated mice at a much reduced level as compared with those in mice treated i.p. with Corynebacterium parvum on 4 days earlier. In correlation with expression of TNF gene in the macrophages, RBS-treated mice were less susceptible to the lethal toxicity of LPS than C.parvum-treated mice. In RBS-treated mice, in vivo elimination of bacteria was enhanced at the early phase of infection with L.monocytogenes or E.coli, resulting in augmentation of host defense against these bacterial infection. These results suggest that adequately enhanced activities of macrophages acting as scavenger phagocytes play important roles in the enhanced resistance against bacteria in mice treated i.p. with RBS.

Adjuvants, Immunologic↗
PubMed1990

Clonal deletion of self-Mls-reactive thymocytes at the early stage in H-2-compatible but Mls-disparate radiation chimeras.

Clonal deletion of T cells capable of recognizing both host-type Mls and donor-type Mls occurred in the peripheral mature T-cell pool in radiation bone marrow chimeras of two H-2-compatible Mls-disparate strain combinations of AKR/J(H-2k,Thy-1.1,Mls-1a) and C3H/He(H-2k,Thy-1.2,Mls-1b). In order to determine further the stage at which the clonal deletion occurs in thymus, we examined the kinetics of thymocytes bearing V beta 6 capable of recognizing Mls-1a in both C3H/He----AKR/J and AKR/J----C3H/He chimeras. An almost complete replacement from host-derived cells to donor-derived cells occurred by Day 21 after reconstitution in both chimeras. At this stage, CD4+CD8+ double-positive thymocytes contained an appreciable number of cells that expressed V beta 6 on their surface, albeit at low intensity, whereas CD4 or CD8 single-positive thymocytes which expressed a high density of V beta 6 were virtually abolished in both C3H----AKR and AKR----C3H chimeras on Day 21. These results suggest that clonal deletion of self-Mls-reactive T cells begins at an early stage when the thymocytes interact with the early appearing donor-derived haemotopoietic cells and relatively radio-resistant host-derived cells in thymus of radiation bone marrow chimeras.

Alleles↗
PubMed1990

Different expression of T-cell receptor beta-chain variable region genes in lymph nodes of lpr mice with different alleles of the major histocompatibility complex.

In order to search for a possible role of abnormally proliferating T cells in developing autoimmune disease in lpr mice, and to define the difference of the T cells among various lpr-congeneic mice with different clinicopathological findings, the T-cell receptor (TcR) V beta gene expression in the enlarged lymph nodes (LN) of C3H/HeJ-lpr/lpr (C3H-lpr), C57BL/6-lpr/lpr (B6-lpr) and MRL/Mp-lpr/lpr (MRL-lpr) mice was analysed. A RNA blot analysis using several V beta-specific probes showed that the V beta 3 gene, whose products are important for recognizing Mlsb/a, was used in B6-lpr and MRL-lpr with the Mlsb/b but not in C3H-lpr with the Mlsb/a. The V beta 5 gene, which is selectively related to I-E molecules, was predominantly used in B6-lpr(I-E-) but not in C3H-lpr(I-E+) nor MRL-lpr(I-E+). Similarly, the V12 gene was also expressed in B6-lpr but not in C3H-lpr. To compare in detail in V beta repertoire among lpr mice with different major histocompatibility complex (MHC) backgrounds, the V beta gene sequences in the cDNA libraries from LN cells of C3H-lpr were analysed, following the recent investigation of B6-lpr mice (Ohga et al., 1989). Eleven beta-chain cDNA out of 32 beta cDNA in B6-lpr and 24 beta-chain cDNA out of 55 beta cDNA in C3H-lpr were found to contain sequences with open reading frames that potentially encode functional TcR beta-chain. The frequencies of the messages in the cDNA libraries from these mice were consistent with the RNA blot analysis using V beta 3- and V beta 5-specific probes. It was notable that 36% of the functional beta-chain mRNA in B6-lpr and 50% of the beta mRNA in C3H-lpr expressed the V beta 8 gene family. When the TcR V beta gene expression was compared between the LN cells in C3H-lpr, B6-lpr and MRL-lpr, as reported by Singer et al. (1986), the usage of V beta genes other than the V beta 8 gene family in B6-lpr (H-2b) LN cells differed significantly from those in C3H-lpr (H-2k) and MRL-lpr (H-2k). The results presented here indicate that the usage of V beta genes is heavily influenced by the genetic background of lpr mice, similar to normal mice, but with preferential usage of the V beta 8 gene family as a common structural feature in lpr gene-induced cell populations.

Alleles↗
PubMed1989

Rearrangements of T-cell antigen receptor gamma and delta chain genes are detected in the long-term cultured bone marrow cells of athymic nude mice but not in those of euthymic mice.

We have previously shown that extrathymic rearrangements of T-cell receptor (TcR) gamma and delta chain genes occur in the peripheral lymphoid tissues of athymic nude mice. To further determine where the TcR gene rearrangements occur in nude mice, we investigated the rearrangement and expression of the TcR genes in the long-term cultured bone marrow (LTBM) cells which were homogenous in developments without mature T cells as assessed by FACS analysis. The LTBM derived from euthymic mice contained TcR gamma and delta chain genes in germline configuration, while gene rearrangements of both locus were detected in the LTBM cells from nude mice. These results suggested that gamma and delta gene rearrangements do occur in the bone marrow cells of nude mice and that the T-cell precursors in bone marrow may be increased in frequency in such animals.

Animals↗
PubMed1989

Expression and sequences of T cell receptor beta-chain variable genes in the enlarged lymph nodes of C57BL/6-lpr/lpr mice.

An autosomal recessive gene, lpr, is responsible for lymphoproliferation and autoimmunity of lpr-mice, in which background genes are also known to influence the development of autoimmune disease. To define the differences in abnormally proliferating T cells between C57BL/6-lpr/lpr and MRL/Mp-lpr/lpr mice, and to try and understand the influence of background in the differing expression of autoimmune disease in both strains, we analysed the sequences of T cell antigen receptor V beta genes expressed in the cells from the enlarged lymph nodes of C57BL/6-lpr/lpr mice. Eleven beta cDNAs out of the 38 C beta-specific cDNAs contained sequences with open reading frames from the beginning of the variable region to the expected termination codons at the end of the constant regions. Notably, 36% of the functional beta-chain mRNAs expressed V beta 8.3 genes, whereas V beta 8.1 and V beta 8.2 genes were not found. These results are consistent with a relatively lower frequency of the V beta 8.1 or V beta 8.2 expressing cells in the hypertrophic lymph nodes of C57BL/6-lpr/lpr mice, detected by KJ16-133 monoclonal antibody. Interestingly, other V beta genes expressed in these mice were completely distinct from those in MRL/Mp-lpr/lpr mice as described by Singer et al. (1986). The different distribution of V beta genes expressed in C57BL/6-lpr/lpr from that in MRL/Mp-lpr/lpr mice might be related to the differences in the genetic background and the expression of lpr gene-associated autoimmunity.

Amino Acid Sequence↗
PubMed1989

Abnormal rearrangements of T-cell receptor genes occur in long-term cultured bone marrow cells of lpr/lpr mice.

To search the abnormality in prethymic T-cell precursors in lpr/lpr(lpr) mice, rearrangement and expression of T-cell receptor (TcR) genes were investigated in long-term cultured bone marrow (LTBM) cells of lpr mice, in which the developmental steps of T-cell precursors may be better synchronized than those in bone marrow (BM) cells. Neither rearrangment nor expression of TCR gamma and delta genes were detected in the LTBM cells from +/+ control mice, whereas some gamma gene rearrangements were detected in those derived from lpr mice, irrespective of the genetic background. When BM cells or LTBM cells from lpr mice were transplanted into supralethally irradiated +/+ mice the lpr-derived BM cells appeared earlier in the thymus of the recipient mice than +/+-derived BM cells and the recipients suffered from lethal wasting syndrome. In addition, the lpr-derived BM cells showed higher activity in colony-forming unit spleen (CFUs) than the +/+-derived BM cells. These results suggest that the T-cell progenitors in the BM of lpr mice may be different not only in quantity but also in quality from those of +/+ mice.

Animals↗
PubMed1989

[Analysis of platelet surface conformation in thrombin-induced aggregation].

We used flow cytometry to investigate the change of platelet membrane glycoproteins (GPIb and GP IIb/IIIa) and the distributions of fibrinogen (Fbg), thrombospondin (TSP) and fibronectin (Fn) on the surface of thrombin-stimulated platelets. The binding of a monoclonal antibody directed at the von Willebrand factor binding site on GPIb decreased in thrombin-stimulated platelets. This antibody caused a reactive delay in thrombin-induced aggregation, but had little influence on aggregability. Slight thrombin-induced aggregation was observed even after blocking the binding of Fbg to GP II b/IIIa. The new expression of GP II b/IIIa was detected on the surface of thrombin-stimulated platelets, whereas there was little increase of Fbg dependent on this GP II b/IIIa. An increase of TSP after thrombin stimulation was observed on the surface of platelets of healthy controls and patients with Glanzmann's thrombasthenia (Type I). The level of on platelet surface was slightly increased by thrombin stimulation. The mechanism involved in thrombin-induced aggregation appears to differ from that in ADP-induced aggregation.

Adult↗
PubMed1988

Functional T cell receptor delta chain gene messages in athymic nude mice.

The rearrangement and expression of T cell antigen receptor (TcR) delta chain genes were investigated in congenitally athymic nude mice. The lymphoid cells derived from nude mice showed evidence of rearranged delta chain genes and a relatively high level of delta chain gene messages. Nucleotide sequence analysis revealed that nude mice contained an in-frame delta chain transcript, composed of V delta 5-D delta 1-D delta 2-J delta 1-C delta genes in the spleen. We have previously described functionally rearranged TcR gamma chain genes in the spleen of nude mice. Taken together, T cell precursors appear to proliferate and differentiate along the extrathymic pathway into TcR gamma/delta-bearing T cells in nude mice.

Amino Acid Sequence↗
PubMed1988

Neonatal hemophilia B with intracranial hemorrhage. Case report.

It is uncommon for infants with hemophilia to have excessive bleeding during the neonatal period. Even if bleeding occurs, it rarely becomes life-threatening, such as in intracranial hemorrhage (ICH). We here report a case of a 4-day-old boy who had intracranial hemorrhage as the first complication of hemophilia B. Computerized axial tomography (CT scan) and ultrasonography were very useful for early diagnosis. Only a few cases of neonatal hemophilia with intracranial hemorrhage have been reported, but the occurrence of this complication is probably more frequent. We reviewed seven cases (including our case) with intracranial hemorrhage as the first manifestation of neonatal hemophilia. Although these infants showed good prognosis as to survival, permanent residual neurological deficits remained in all of them. It is emphasized that intracranial hemorrhage due to hemophilia may occur in neonates even without a family history. Urgent neuroimaging and coagulation studies are necessary for an early and adequate diagnosis.

Cerebral Hemorrhage↗
PubMed1987

Familial erythrophagocytic lymphohistiocytosis: surface marker analysis using monoclonal antibodies.

Surface marker analysis of atypical cells, present at elevated levels in the peripheral blood of a 2-yr-old patient with familial erythrophagocytic lymphohistiocytosis (FEL), was performed with monoclonal antibodies. The atypical cells expressed T11, T8, Ia and LeuM2 antigens, markers of suppressor/cytotoxic T lymphocyte and monocyte. The monoclonal antibody-defined surface markers were thus distinguishable from those of other lymphoproliferative disorders clinically resembling FEL.

Antibodies, Monoclonal↗
PubMedDate not supplied

Interferon-alpha therapy for chronic active Epstein-Barr virus infection: potential effect on the development of T-lymphoproliferative disease.

PURPOSE: A patient with aggressive chronic active Epstein-Barr virus (CAEBV) infection is described whose disease activity subsided after interferon (IFN)-alpha therapy. PATIENT AND METHODS: The patient had intermittent fever, cytopenia, liver dysfunction, hepatosplenomegaly, abnormal titers of EBV-associated antibodies, and positive EBV genomes. RESULTS: Despite repeated trials of the antiviral agents prednisolone and gamma-globulin, his condition deteriorated. The administration of IFN-alpha (1 x 10(5) U/kg subcutaneously 3 times per week) led to a dramatic clinical improvement. During the IFN-alpha therapy, the rearrangement bands of T-cell antigen receptor genes disappeared assessed by Southern blotting with a decrease in the number of activated T cells, although the EBV-genome remained evident. CONCLUSIONS: These observations suggest that IFN-alpha is useful in managing CAEBV, possibly restraining the clonal development of T-lymphoproliferative disease (LPD) and EBV-associated B-LPD, although it does not eradicate the proliferation of EBV.

Antiviral Agents↗
PubMedDate not supplied

Central nervous system T-cell lymphoproliferative disorder in a patient with chronic active Epstein-Barr virus infection.

PURPOSE: Central nervous system (CNS)-T cell lymphoproliferative disorder (T-LPD) developing during the course of chronic active Epstein-Barr virus (CAEBV) infection is reported. PATIENTS AND METHODS: CAEBV was diagnosed in a 14-month-old boy with fever, cytopenia, hepatosplenomegaly, and abnormal high titers of anti-Epstein-Barr virus (EBV) antibodies. At 8 years of age, he had a splenectomy because of progressive disease. RESULTS: After 27 months of clinical remission, muscle weakness and paresthesia developed. Magnetic resonance imaging of his brain showed spotty T2 prolongation in left parietal, bilateral frontal, and temporal white matter with meningeal enhancement. Brain biopsy revealed the cerebral infiltration of CD3+, CD4+, CD8-, CD45RO+, CD56-, and EBV-encoded RNA 1+ cells. CONCLUSIONS: The CNS involvement of EBV-associated T-LPD is a rare but serious complication in CAEBV without known underlying immunodeficiency.

Acute Disease↗
PubMedDate not supplied

Kimura's disease with bilateral auricular masses.

We report an unusual case of Kimura's disease. An 81-year-old Japanese woman was shown to have bilateral auricular masses that had begun to enlarge 6 years before. On CT scans, slightly high-density masses with faint contrast enhancement were seen. The masses were heterogeneous and hypointense on T1-weighted MR images, were slightly hyperintense on T2-weighted MR images, and showed heterogeneous enhancement after the administration of contrast material. Kimura's disease should be included in the differential diagnosis of bilateral auricular tumors.

Aged↗