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T Akagi

Publications and source records attributed to T Akagi.

At least 145 records · Page 8Linked to original sources
PubMed1996

Comparison of the structural features of ubiquinone reduction sites between glucose dehydrogenase in Escherichia coli and bovine heart mitochondrial complex I.

To characterize the structural features of the ubiquinone reduction site of glucose dehydrogenase (GlcDH) in Escherichia coli, we performed structure/activity studies of a systematic set of synthetic ubiquinone analogues and specific inhibitors (synthetic capsaicins) of this site. Considering the proposed similarity of the quinone binding domain motif between GlcDH and one subunit of mitochondrial complex I [Friedrich, T., Strohdeicher, M., Hofhaus, G., Preis, D., Sahm, H. & Weiss, H. (1990) FEBS Lett. 265, 37-40], we compared the structure/activity profiles of the substrates and inhibitors for GlcDH with those for bovine heart mitochondrial complex i. With respect to GlcDH, replacement of one or both methoxy groups in the 2 and 3 positions of benzoquinone ring by ethoxy group(s) resulted in a drastic decrease in the electron accepting activity. The presence of a 5-methyl group and the conformational property of the 6-alkyl side chain did not significantly contribute to the activity. These results suggested that only half of the benzoquinone ring (the moiety corresponding to the 2 and 3 positions) is recognized by the quinone reduction site in a strict sense. In contrast, quinone analogues with structural modifications at all positions in the benzoquinone ring retained the activity with mitochondrial complex I. This finding indicated that the catalytic site of complex I is spacious enough to accommodate a variety of structurally different quinone derivatives. The correlation of the inhibitory potencies of a series of synthetic capsaicins between the two enzymes was very poor. These findings indicated that the binding environment of ubiquinone in GlcDH is very specific and differs from that in mitochondrial complex I.

Animals↗
PubMed1996

Clonal analysis by polymerase chain reaction of B-cell lymphoma with late relapse: a report of five cases.

BACKGROUND: Little is known about the clonal heterogeneity of non-Hodgkin's lymphoma between presentation and relapse, although several such reports have been published on acute lymphoblastic leukemia. METHODS: We examined five patients with B-cell lymphoma who relapsed more than 5 years after initial presentation. Formalin fixed, paraffin embedded tissues were analyzed for clonal immunoglobulin heavy chain gene rearrangement by the polymerase chain reaction (PCR) and sequencing of the PCR products. Four specimens retained the original histologic type, but one showed histologic transformation from diffuse large cell lymphoma to follicular small cleaved cell lymphoma. RESULTS: Although the size of the PCR products looked identical on the gel between presentation and relapse in all patients, only three of the four specimens that retained the original type had identical gene rearrangements at both presentation and relapse. One of these four and the fifth specimen showed novel gene rearrangements. CONCLUSIONS: This study suggests that late relapse lymphoma may present as a new clone. Sequencing of the PCR products is important in the evaluation of clonal heterogeneity.

Adult↗
PubMed1996

Protection of rabbits against HTLV-II infection with a synthetic peptide corresponding to HTLV-II neutralization region.

Rabbit immune sera raised against synthetic peptides of the HTLV-II envelope gp46 region were examined for HTLV-II neutralization ability by HTLV-vesicular stomatitis virus (VSV) pseudotype assay and syncytium inhibition assay. HTLV-II neutralization activity was detected in the sera against HTLV-II Env gp46, 80-103 but not in those to HTLV-II Env gp46, 171-196. Three rabbits immunized with the synthetic peptide of HTLV-II Env gp46, 80-103 and three non-immunized rabbits were challenged with intravenous inoculation of an HTLV-II-producing human cell line (MOT, 1 x 10(7) cells). The non-immunized rabbits showed seroconversion for HTLV-II after 2 weeks and maintained persistent infection but the immunized rabbits were protected from HTLV-II infection. Nested or repeated polymerase chain reaction revealed the presence of HTLV-II provirus sequences in the non-immunized rabbits but not in the immunized rabbits. These results suggest that peptide vaccination with a synthetic peptide corresponding to the HTLV-II neutralization region is useful for preventing HTLV-II infection.

Amino Acid Sequence↗
PubMed1996

The Fas antigen is detected on immature B cells and the representative cell lines show Fas-mediated apoptosis.

The expression and functions of Fas antigen, a major regulator of apoptosis, in T-cell selection have been intensively investigated, but little is known about its expression i immature B cells which are also selected in the bone marrow, and plasma cells which are at the terminal stage of B-cell differentiation and are designed to die. We examined bone marrow cells and found Fas antigen on these cells at low levels. Next we analysed Fas expression and susceptibility to anti-Fas antibody-mediated apoptosis on B-cell lines representing various stages of differentiation. We also examined the expression of Bcl-2 and Bax on these lines, which were intimately related to apoptosis. Fas antigen was almost negative on pre-pre-B cell lines and was detected on pre-B-cell lines at low levels. All plasma cell lines expressed Fas at a low to moderate level. Some cell lines with peripheral B-cell phenotype expressed Fas antigen. Except for the Burkitt cell lines and one plasma cell line, susceptibility to Fas-mediated apoptosis depended on Fas expression. Bcl-protein was detected on all but one cell line and Bax was detected on 15/23 lines, but neither were related to cellular differentiation or Fas expression.

Apoptosis↗
PubMed1996

Metastatic potential of lymphoma/leukemia cell lines in SCID mice is closely related to expression of CD44.

To investigate whether the lymphocyte homing receptors, adhesion molecules regulating normal lymphocyte traffic, influence the dissemination of lymphoma cells, 24 lymphoma/leukemia cell lines were inoculated into SCID mice subcutaneously, and the correlation between the expression of the adhesion molecules and the metastatic potential of the cell lines was examined. Among the six adhesion molecules examined (LFA-1, ICAM-1, CLA, VLA-4, L-selectin and CD44), L-selectin increased the incidence of lymph node metastasis, and CD44 expression was related to both lymph node and organ (hematogenous) metastasis. A monoclonal antibody to the standard form of CD44 (CD44s), Hermes-3, inhibited the local growth and remote metastasis of CD44+ cell lines. Thus, it is concluded that at least CD44s expression is important in both lymphatic and hematogenous metastasis.

Animals↗
PubMed1996

Abnormal expression of the human CD44 gene in early colorectal malignancy with special reference to variant exon 9 (9v).

AIMS: To examine the expression of CD44 variant exon 9 in early colorectal malignancies. METHODS: Formalin fixed, paraffin wax embedded tissue sections from 30 cases of tubular adenoma and 35 cases of adenoma with focal carcinoma of the colon were examined immunohistochemically using a monoclonal antibody (MAb 11.24) directed against CD44-9v. RESULTS: In the normal colorectal mucosa immunoreactivity was confined to the basal part of the crypts and was expressed in less than 10% of crypt cells. CD44-9v was expressed in the superficial part of tubular adenoma with mild atypia in 67% of the cases and in 19% of the tumour cells. The immunoreactivity was observed along the basement membrane in mild atypia, as in the non-neoplastic crypts. In the course of progression to severe atypia the spatial polarity of immunoreactivity was lost, and the extent of CD44-9v expression increased in intensity and in the percentage of positive cases and positive cells. In the carcinomatous lesions of adenoma with focal carcinoma, 94% of the cases and 44% of the tumour cells were positive for CD44-9v protein. CONCLUSION: CD44-9v may be overexpressed at the early stage of colorectal tumorigenesis and this increase continues throughout the course of the disease.

Adenoma↗
PubMed1996

Detection of Epstein-Barr virus RNA and related antigens in non-neoplastic lymphoid lesions.

To elucidate the latent state and reactivation of Epstein-Barr virus (EBV) in non-neoplastic lymphoid lesions, we investigated 144 non-neoplastic lymphoid lesions by in situ hybridization (ISH) to detect the expression of EBV-encoded small RNAs (EBER)-1 and BCRF-1 and by immunostaining for latent membrane protein (LMP)-1 and ZEBRA. ISH for EBER-1 detected EBER-1-positive cells (EPC) in 31 of the 144 examined lesions (22%). EPC were detected in 4 of 49 cases of nonspecific lymphoid hyperplasia, in 16 of 20 abscess-forming granulomatous lymphadenitis (AFGL), 5 of 25 Kikuchi's disease, and in 3 of 3 infectious mononucleosis. LMP-1 was expressed in 6 of 124 non-neoplastic lymphoid lesions (4.8%). LMP-1-positive cells were observed in 6 of the 31 EBER-1-positive cases (19%). EPC were detected significantly more frequently in LMP-1- and ZEBRA-positive specimens than in the LMP-1- and ZEBRA-negative specimens. BCRF-1 was expressed in 4 of 11 cases examined: 2 of 3 AFGL, 1 of 2 Kikuchi's disease, and in the 1 case of atypical lymphoid hyperplasia. This study suggests that Epstein-Barr virus is prevalent and can be reactivated in the lymph nodes effaced by destructive inflammation, such as AFGL. Such inflammation may provide a local milieu that is conducive for EBV to enter the lytic cycle.

Base Sequence↗
PubMed1996

Variable expression of Epstein-Barr virus latent membrane protein I in Reed-Sternberg cells of Hodgkin's disease.

Reed-Sternberg cells (RS cells) of Hodgkin's disease (HD) are frequently infected with Epstein-Barr virus (EBV) and express EBV-encoded nonpolyadenylated RNA transcripts (EBER)-1. EBV latency has been classified into three distinct forms: Latency I, expressing only one of the latent proteins, EBV nuclear antigen (EBNA)-1, latency II, coexpressing EBNA-1 and LMPs, and latency III, expressing all latent viral proteins. RS cells express LMP-1 in addition to EBNA-1 and are considered to be EBV latency II frequently encountered in nasopharyngeal carcinoma. We examined 13 cases of EBV-infected HD by combined EBER-1 in situ hybridization and immunostaining for LMP-1. All of the RS cells expressed EBER-1, but a substantial number of EBER-1+ RS, cells were negative for LMP-1. The percentage of LMP-1+ RS cells out of EBER-1+ RS cells varied from 7% to 100% (average 69%). In this study, we showed that all EBV-infected RS cells were not restricted to latency II, and some belonged to latency I.

Herpesvirus 4, Human↗
PubMed1996

Unsuspected gastric granulocytic sarcoma in a patient with myelodysplastic syndrome.

Granulocytic sarcoma (GS) is an uncommon and localized extramedullary tumor composed of immature granulocytic cells. Most GS reported in large series were not associated with overt acute myelogenous leukemia. Gastric perforation occurred during prednisolone therapy in a 72-year-old Japanese male with a four-month history of a myelofibrosis-like state. Subtotal gastrectomy was performed for a suspected gastric ulcer perforation. Gastric histologic, immunohistochemical and cytochemical examination revealed diffuse infiltration by sheets of myeloblasts and promyelocytes with scant or moderately abundant cytoplasm including a few eosinophilic myelocytes. Bone marrow study done in one month after the operation disclosed refractory anemia with excess of blasts (RAEB). Leukemic transformation occurred two months later, and a subcutaneous tumor appeared on the forehead. The forehead tumor predominantly consisted of myeloblasts without evidence of maturation. Both the stomach and forehead tumors were examined immunohistochemically with a panel of monoclonal antibodies (LCA, L26, MT1, UCHL1, OPD4, LN-1, LN-2, LN-3, MB1, Leu-M1, PM) and polyclonal antibodies (lysozyme, alpha 1-antitrypsin, alpha 1-antichymotrypsin, S-100 protein, lactoferrin), as well as naphthol-ASD-chloroacetate esterase staining to investigate and characterize the reliable marks for GS, and the patient was diagnosed as GS. We found that gastric GS may occur in a myelofibrosis-like state followed by RAEB of myelodysplastic syndrome and that naphthol-ASD-chloroacetate esterase staining and immunohistochemical detection of MT1, lysozyme, and alpha 1-antitrypsin were the most reliable markers for confirming the diagnosis of GS.

Aged↗
PubMed1996

[A case of advanced esophageal cancer showing good partial response by combination therapy of low dose 5-FU and low dose CDDP].

A 66-year-old man with a complaint of dysphagia was diagnosed as advanced esophageal cancer. Barium swallow examination of the esophagus showed a narrowing 10 cm in length at Ei (type 3), and biopsy specimen from the lesion on endoscopic examination revealed adenosquamous carcinoma. Multiple lymph node metastasis were detected by CT scan. He was treated with a combination of low dose 5-fluorouracil (5-FU) and low dose cisplatin (CDDP). The regimen consisted of 5-FU (300 mg/body/day continuous infusion) and CDDP (10 mg/body/day continuous infusion) for 3 weeks. After 2 courses of this regimen, his symptoms disappeared, and only mild irregularity of the esophageal wall remained on Barium swallow examination. The effect of the therapy was evaluated as a partial response. No side effect was observed. From this case, the possibility that CDDP is able to function as a biochemical modulator for 5-FU was suggested.

Aged↗
PubMed1996

Regulation of interleukin-2 receptor gamma chain mRNA expression in human monocytic cell line THP-1.

The interleukin-2 receptor (IL-2R) gamma chain (gamma c chain) is shared by IL-4R, IL-7R, IL-9R, and IL-15R and plays an important role in regulation of the immune system. However, its regulation in monocytic cell lines has not been well clarified. We examined the expression and regulation of the IL-2R alpha, IL-2R beta, gamma c chain, IL-4R and IL-7R mRNA in a human monoblastic leukemia cell line, THP-1. Unstimulated THP-1 cells constitutively expressed a low level of gamma c chain and IL-4R mRNA. Phorbol myristate acetate (PMA) induced macrophage-like differentiation and up-regulated the gamma c chain mRNA expression in THP-1 cells. This effect of PMA was suppressed by the protein kinase inhibitors H-7 and staurosporine. PMA did not affect the expression of the other IL-R mRNAs examined. 1 alpha, 25(OH)2D3 and interferon-gamma also induced differentiation of THP-1 cells, but these reagents did not affect the expression of the IL-R mRNAs in THP-1 cells. These findings suggest that the expression of the gamma c chain mRNA is regulated by the PMA-dependent pathway and is not associated with that of the other IL-R mRNAs.

Calcitriol↗
PubMed1996

[In situ detection of Epstein-Barr virus in the non-neoplastic gastric glands and infiltrated lymphocytes].

Recently, clonal EBV-DNA and/or EBV-encoded small RNA(EBER1) have been detected in some gastric carcinomas. We reported the first observation of EBV infection in gastric glands with intestinal metaplasia, and characterized the EBV-infected lymphocytes which infiltrated in gastric mucosa. To determine the cellular location of EBV, EBER1 in situ hybridization(ISH) with an EBER1 oligonucleotide probe was applied to paraffin sections of the non-neoplastic gastric mucosa in 80 cases of gastric carcinoma and 49 cases of gastric ulcer. Not only was EBER1 expression detected in the nucleus of gastric cancer cells(5 cases) but also in non-neoplastic gastric epithelial cells(3 cases) and in infiltrated lymphocytes(40 cases). A single or a few shedding non-neoplastic epithelial cells in 2 cases of EBV-associated gastric cancer showed EBER1 expression. In one case, EBER1 was observed in all of the epithelial cells of a few gastric glands with intestinal metaplasia, suggesting that the stem cells of the metaplastic gastric glands were infected with EBV. EBV DNA was also detected in the EBER1-positive metaplastic glands scratched from the paraffin section by a single cell PCR method with a BamHI W primer pair. However, immunohistochemical examination showed that these metaplastic glands lacked expression of EBNA2 and LMP-1. The observation of these rare EBV-infected metaplastic glands reinforces the pre-transformation EBV infection hypothesis for EBV-associated gastric carcinoma. The double staining using ISH and immunohistochemistry revealed that EBER1 positive lymphocytes showed a B cell marker of L26(< 50%) but not T cell markers of UCHL1 and OPD4.

B-Lymphocytes↗
PubMed1995

Characterization of T cells immortalized by Tax1 of human T-cell leukemia virus type 1.

Peripheral blood T cells were immortalized in vitro by introduction of the Tax1 gene of human T-cell leukemia virus type 1 (HTLV-1) with a retroviral vector and were characterized for transformation-associated markers. Long-term observation showed that these Tax1-immortalized T cells eventually exhibited very similar features that were characteristic of HTLV-1-immortalized T cells, ie, increased expression of egr-1, c-fos, IL-2R alpha, and Lyn and decreased expression of Lck and cell-surface CD3 antigen. Among these changes, an increase in the expression of Lyn and a decrease in the expression of Lck and cell-surface CD3 antigen were observed only in Tax1-immortalized T cells after long-term culture. The expression level of Tax1 protein did not differ significantly between early and late passage of cells, and the cellular clonality was found to be the same by the analysis of the retroviral vector integration site and the T-cell receptor beta-chain gene rearrangement pattern. These changes in the expression of Lyn, Lck, and cell-surface CD3 antigen probably resulted from indirect effects of Tax1 that appeared after extended culture.

Antigens, Differentiation↗