PubMed Health⌕ Search

Biomedical subjects

R Ohno

Publications and source records attributed to R Ohno.

At least 19 recordsLinked to original sources
PubMed1992

The effect of amino acid substitution at position 219 of Citrobacter freundii cephalosporinase on extension of its substrate spectrum.

The cephalosporinase of Citrobacter freundii GN346 is a class-C beta-lactamase comprising 361 amino acids. The substitution of the glutamic acid at position 219 in the enzyme by lysine was previously shown to broaden its substrate specificity to unfavorable substrates such as oxyimino cephalosporins [Tsukamoto, K., Ohno, R. & Sawai, T. (1990) J. Bacteriol. 172, 4348-4351]. To investigate the cause of this phenomenon, Glu219 was changed to glutamine, cysteine or tryptophan. All the resultant enzymes showed higher cefuroxime-hydrolytic activities than the wild type, the order of increasing cefuroxime-hydrolytic activity being as follows: Trp greater than Lys greater than Cys greater than Gln greater than Glu. The rate of hydrolysis of cefuroxime by the Trp219 enzyme was approximately 3 x 10(4) times that of the wild-type enzyme. The order of increasing cefuroxime hydrolysis was approximately proportional to the molecular volume of the amino acid substituted and independent of the ionic character of the amino acids. The cysteine residue at position 219 in the Cys219 enzyme allowed its complete reaction with an SH-blocking reagent, 4-chloromercuriphenylsulfonic acid. The modified enzyme with the bulkier residue showed a 45% higher cefuroxime-hydrolytic activity than the untreated enzyme. These results suggested that extension of the substrate spectrum may be attributed to alteration in the configuration of the enzyme around position 219.

Amino Acids↗
PubMed1992

Phase II study: treatment of non-Hodgkin's lymphoma with an oral antitumor derivative of bis(2,6-dioxopiperazine).

BACKGROUND: Although razoxane (ICRF-159), a derivative of bis(2,6-dioxopiperazine), has shown significant antitumor activity in several murine tumors, inadequate bioavailability has limited its clinical efficacy. Sobuzoxane (MST-16), another derivative of bis(2,6-dioxopiperazine), has shown activity against a broad spectrum of murine tumors and human tumor xenografts in nude mice and a lack of cross-resistance to vincristine, doxorubicin, cyclophosphamide, fluorouracil, etoposide, and mitomycin C. These findings suggest that MST-16 has a mode of cytocidal activity different from that of other antitumor agents. PURPOSE: The present late phase II study was conducted to evaluate the clinical efficacy and toxicity of MST-16 in non-Hodgkin's lymphoma (NHL). METHODS: As part of a multi-institutional cooperative study, we conducted a study of MST-16 in 27 patients with NHL who were assessable for drug efficacy and toxicity. MST-16, a bis(2,6-dioxopiperazine) analogue and an inhibitor of topoisomerase II, was administered orally at a dose of 1600 mg/m2 a day for 5-7 days at intervals of 2-3 weeks. RESULTS: Response consisted of one complete remission and seven partial remissions in 27 assessable patients. Response was achieved at a median of 13 days (range, 9-62 days) after initiation of therapy and lasted a median of 46 days (range, 29-155 days). Major toxic effects were leukopenia in 70% of the patients, thrombocytopenia in 44%, and gastrointestinal disorders in 37%. CONCLUSIONS: MST-16 was shown to be effective in NHL and deserves further clinical trial, since the drug shows little cross-resistance to available antitumor drugs. IMPLICATIONS: Phase II clinical studies of MST-16 in treatment of breast cancer, gastric cancer, and adult T-cell leukemia and lymphoma are also being conducted in Japan. Future trials of combination chemotherapy using MST-16 with other antitumor drugs are warranted in view of the additive effects observed in studies of MOLT-3 cells and studies of L1210 leukemia in mice.

Administration, Oral↗
PubMed1992

Antibody dependent cell mediated cytotoxicity on human cervical carcinoma cell line, ME-180, with human monoclonal antibody.

A human monoclonal antibody (MCA), CLN-IgG, showed cytotoxic effect in vitro against the cervical carcinoma cell line, ME-180, by antibody dependent cell-mediated cytotoxicity (ADCC). To determine which fractions of cells in peripheral blood lymphocyte (PBL) mediate ADCC, PBL were separated with nylon wool column and sheep red blood cells (SRBC). Both adherent cells (monocyte) and non-T, non-B cells showed cytotoxicity by ADCC. Human non-T, non-B cells showed higher cytotoxic activity against ME-180 cells than monocytes. Furthermore murine effector cells were less effective in ADCC than human effector cells with human MCA.

Antibodies, Monoclonal↗
PubMed1992

Effective treatment of adult T cell leukemia/lymphoma with a novel oral antitumor agent, MST-16.

Adult T cell leukemia/lymphoma (ATLL) induced by human T cell leukemia virus I is resistant to conventional therapy. Six patients with ATLL were treated with a new antitumor agent, MST-16, which is a derivative of bis(2,6-dioxopiperazine). Two patients achieved complete remission, lasting 12 months and more than 8 months, and 2 others partial remission, lasting 2 months and 6 weeks, respectively. The major toxicity was myelosuppression. Other toxicities were not severe and were well tolerable. Orally administered MST-16 is a promising agent for the treatment of ATLL.

Administration, Oral↗
PubMed1992

Characterization of the immunoglobulin heavy chain complementarity determining region (CDR)-III sequences from human B cell precursor acute lymphoblastic leukemia cells.

Sequence analysis of the immunoglobulin heavy chain complementarity determining region (CDR)-III of B-lineage cells at various stages has provided important insights concerning B cell maturation and selection. Knowledge of human CDR-III sequences has been relatively limited compared with that of the murine system. We analyzed the CDR-III sequences of B cell precursor acute lymphoblastic leukemia (pre-B ALL) cells in 23 newly diagnosed and 10 relapsed patients, in order to elucidate the organization of CDR-III in B cell precursors. We found a very low frequency of somatic mutations in D and JH regions, preferential use of DLR, DXP, DHQ52, and DN elements, and of 3' side JH segments, and no predominant usage of D coding frames. Unusual joinings such as VH-D-D-JH and VH-JH were observed in three, and one sequences, respectively. We compared the CDR-III sequences derived from 10 patients between diagnosis and relapse. Two of them had three spots of mutated nucleotides at relapse, all of which were found in the N region near the D segments. Our data showed the possibility of somatic mutation at relapse, in addition to developmentally regulated rearrangement of the immunoglobulin gene at the stage of B cell precursors.

Adolescent↗
PubMed1992

Remission induction of acute promyelocytic leukemia by all-trans-retinoic acid: molecular evidence of restoration of normal hematopoiesis after differentiation and subsequent extinction of leukemic clone.

Sequential molecular and cellular changes during remission induction were investigated in a case of acute promyelocytic leukemia (APL) treated with all-trans-retinoic acid (ATRA). By means of clonality analysis, the assessment of the retinoic acid receptor alpha gene alterations, as well as conventional cytologic studies, it was demonstrated that remission induction of APL by ATRA proceeds in two steps: first, the differentiation of the leukemic clone to mature granulocytes and its subsequent extinction; second, proliferation/differentiation of the residual normal clones to restore polyclonal hematopoiesis.

Adult↗
PubMed1992

[Supportive therapy in cancer treatment with colony stimulating factors and evaluation of their effect].

Several tumors are now curable. However, intensive chemotherapy or bone marrow transplantation is required for the cure, and thus myelosuppression and resultant serious infections are major obstacles for the cure of cancer. G-CSF and M-CSF are commercially available in Japan. By strict comparative studies, G-CSF has been shown to be a useful drug, shortening the recovery of neutrophils and reducing the incidence of documented infections. There have been no convincing data that G-CSF stimulates the regrowth of myeloid leukemia in vivo, and thus G-CSF is safe even in myeloid leukemia, if used with precaution.

Cell Division↗
PubMed1992

Randomized study of individualized induction therapy with or without VCR, and of maintenance of 4 or 12 courses in adult AML: JALSG-AML87. Japan Adult Leukemia Study Group (JALSG).

We asked 2 questions in this study. First was the additional effect of VCR in induction therapy, and the second was the duration of maintenance therapy. Adult AML were treated by an individualized response-oriented induction therapy with behenoyl Ara-C 200 mg/m2 daily + 6MP 70 mg/m2 daily + prednisolone 40 mg/m2 on days 1-4 + DNA 40 mg/m2 on days 1-3 and additionally on days 7, 8, 11, 12 (for M3, DNR 50 mg/m2 daily) (BHAC-DMP) until bone marrow became severely hypoplastic with less than 5% of blasts. Patients were randomized to BHAC-DMP or BHAC-DMP + VCR 0.35 mg/m2 on days 1-4. After obtaining CR, 3 courses of intensive consolidation therapy were given together with I.T. MTX+Ara-C+PSL. Maintenance intensification therapy was randomized to either 4 or 12 courses given every 2 months. Patients of age greater than or equal to 60 received about 2/3 reduced doses. From June 1987 to Sept. 1989, 265 consecutive adult AML were registered from 19 institutions and 258 were evaluable. Age ranged from 15 to 79 (med., 48). Out of 258, 200 (77.5%) achieved CR (80% in 209 of age less than 60 and 65% in 49 of age greater than or equal to 60). Unexpectedly, addition of VCR reduced the high CR rate of BHAC-DMP significantly (84% to 70%, p = 0.007). At the median follow-up of 37 mo., overall survival is 37%, and event-free survival (EVS) 27%. Survival, continuing CR and disease-free survival (DFS) rates of 200 CR cases are 45%, 40% and 35%, respectively. Patients received 12 courses of maintenance therapy showed better DFS (P = 0.0555). The VCR group had significantly worse EFS. By multivariate analysis, significant prognostic factors for the achievement of CR were age less than 60, PS 0-2 and no addition of VCR. Significant factors for longer DFS were induction of CR by one course, FAB M3 or M5 and age less than 50. The present multi-institutional study confirmed the high CR rates of the response-oriented individualized therapy reported from several centers in Japan, but failed to support an additional effect of VCR reported from one center.

Acute Disease↗
PubMed1992

All-trans-retinoic acid induced enrichment of functionally normal neutrophils in vivo in a patient with acute promyelocytic leukemia.

A patient with resistant acute promyelocytic leukemia was treated with all-trans-retinoic acid (45 mg/m2 per day for 42 days) and obtained complete remission at day 14. Analysis of the neutrophils from the patient at day 7 demonstrated that they were indistinguishable from neutrophils from normal individuals as far as this is assessed by presently available functional tests. Furthermore, the degree of peroxidase positivity of neutrophils obtained from the patient was similar to control values. Thus, taken together with the hematologic features, all-trans-retinoic acid induces leukemic promyelocytes to become functionally normal neutrophils. This therapy is particularly suitable in obtaining complete remission in patients with acute promyelocytic leukemia with neutropenia with or without previous chemotherapy.

Female↗
PubMed1991

A combination trial of human lymphoblastoid interferon and bestrabucil (KM2210) for adult T-cell leukemia-lymphoma.

Both human lymphoblastoid interferon (HLBI) and bestrabucil, the conjugate of chlorambucil and beta-estradiol, have antitumor activity against adult T-cell leukemia-lymphoma (ATLL). Because an in vitro study showed that these two agents combined had a synergistic antiproliferative effect on MOLT-4 and WI-38VA13 cell lines, the authors evaluated the clinical efficacy of this combination in a pilot study with a poor-risk group of ATLL patients. The patients were treated daily with 6 x 10(6) IU of HLBI subcutaneously and 100 mg of bestrabucil orally. In patients with lymphoma-type ATLL or hypercalcemia, prednisolone also was given daily. Of 12 patients suitable for evaluation, nine had partial responses, one had a minor response, and two had no response. All five patients with skin infiltration and both patients with hypercalcemia responded. A history of prior chemotherapy did not affect the response rate. The time to clinical response was 3 to 16 days (median, 11 days) after initiation of treatment. The response duration was 4 to 108+ weeks (median, 9 weeks), but all patients except one relapsed, even during continuing treatment. No serious side effects were observed. Although the response rate with this combination treatment was high, the response duration was short, and other treatments would have to be added to achieve control of this aggressive disease.

Adult↗
PubMed1991

Activated T lymphocyte subsets in experimental allergic neuritis.

Changes in activated T cell subsets in peripheral blood were examined during the course of experimental allergic neuritis (EAN), using two-color immunofluorescence flow cytometry. Both CD4+ and CD8+ activated T cells decreased transiently before the onset of clinical signs, and increased just around the time of onset of the disease. In contrast, during the recovery phase, the numbers of CD4+ activated T cells returned to the normal range, whereas CD8+ activated T cells continued to increase. These findings imply that activation of CD4+ helper/inducer cells contributes mainly to the evolution of EAN, and that of CD8+ suppressor cells are necessary for recovery.

Animals↗
PubMed1991

Treatment of myelodysplastic syndromes with orally administered 1-beta-D-arabinofuranosylcytosine-5'-stearylphosphate.

1-beta-D-Arabinofuranosylcytosine-5'-stearylphosphate (fosteabine) was administered orally to patients with myelodysplastic syndromes (MDS); refractory anemia with excess of blasts (RAEB), RAEB in transformation, acute leukemia derived from RAEB and chronic myelomonocytic leukemia, in an early phase II study in a multi-institutional study. Among 62 evaluable patients, 2 patients achieved a complete remission, 6 a good response and 8 partial response by daily oral administration of 100-200 mg of fosteabine. The overall response rate was 25.8%. The response rates were almost the same among the four subtypes of MDS. Responses were reached 2-23 weeks (median, 8 weeks) after the start of therapy and continued for 3-50 weeks (median, 10 weeks). Major side effects were myelosuppression and gastrointestinal toxicities. In spite of the disadvantages, such as unpredictable absorption, this newly developed orally administrable cytarabine analogue will be a useful drug in the treatment of MDS.

Adult↗
PubMed1991

[Recent progress in the treatment of acute leukemia].

Acute leukemia has become a curable disease. In 3 studies for adult AML (BHAC-DMP, BHAC-DMP (II) and M-85) at Nagoya University Hospitals from 1979 to 1987, intensive induction resulted in higher cure rate, and the reduction of the blasts in bone marrow at 2 weeks after the initiation of therapy to less than 20% was the most important prognostic factor to predict the long CR. However, it seemed impractical to give very intensive chemotherapy during the induction because of high frequency of complications due to prolonged myelosuppression. Thus, consolidation should be as intensive as possible. In M-85 protocol, the predicted 5-years survival and disease-free survival (DFS) of CR cases are 70 and 53% respectively. The result of JALSG-AML 87 study seems to confirm the above result. As for the indication of bone marrow transplantation (BMT) at the first CR for adult AML, only a prospective randomized study will answer this important question. In case that DFS of chemotherapy will exceed 40 to 45%, it seems be wise to give chemotherapy first, and then BMT when the leukemia relapse. Differentiation induction therapy seems to be indicated in acute promyelocytic leukemia, although a confirmative study is awaited.

Acute Disease↗
PubMed1991

Establishment and characterization of a new human Bence Jones-type myeloma cell line, NOP-2.

A new human myeloma cell line NOP-2, producing immunoglobulin (Ig)-lambda-light chain was established from a patient with Bence Jones-type multiple myeloma. Morphologically, the cell line had plasmacytoid characteristics by light- and electron-microscopic examination. Phenotypic studies of NOP-2 cells revealed no surface Ig, but they were positive for cytoplasmic Ig-lambda, OKT10 (CD 38), and PCA-1. Epstein-Barr nuclear antigen was not detected. Chromosomal abnormalities of t(11;14) and t(8;22) were found in both NOP-2 cells and the original myeloma cells obtained from the patient. NOP-2 cells produced and secreted Ig-lambda light chain, but lacked immunoglobulins of any heavy chains. Rearrangements of both immunoglobulin heavy- and light-chain genes were observed in NOP-2 cells, though the cells expressed detectable mRNA only for Ig-lambda light chain. This cell line may serve as a useful model for understanding the hierarchy of human immunoglobulins and the pathophysiology of Bence Jones-type multiple myeloma.

Antigens, Neoplasm↗
PubMed1991

Expression of H-related antigen on human megakaryocytes and megakaryocytic leukemia cells.

A mouse monoclonal antibody (MoAb), MG-2, was produced by immunizing a characterized human megakaryoblastic cell line, MEG-01. Since MG-2 reacted with erythrocytes of all ABH blood groups except Oh (O Bombay), and since anti-H MoAb inhibited MG-2 binding to MEG-01 cells, MG-2 is considered to recognize a molecule closely related to blood group antigen H. MG-2 reacted more strongly with normal smaller sized megakaryocytes than with larger sized ones, and not with platelets. The expression of the intrinsic H-related antigen on MEG-01 cells decreased concomitant to megakaryocytic differentiation induced by phorbol esters. This H-related antigen was expressed on leukemia cells with the megakaryocytic features from blast crisis of chronic myelogenous leukemia and acute megakaryoblastic leukemia.

ABO Blood-Group System↗