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M Okubo

Publications and source records attributed to M Okubo.

At least 181 records · Page 10Linked to original sources
PubMed1989

Subacute toxicity of (-)15-deoxyspergualin in BALB/c mice. I. Hematological study.

(-)15-Deoxyspergualin (DSP), a bacterial metabolite obtained from Bacillus laterosporus, was shown to effectively suppress autoantibody production in mice and alloimmune reaction in mice and rats. Its potential toxicity and safety margin in BALB/c mice were studied by administering the drug, 0.5-5.0 mg/kg body weight, s.c., 6 days/week for 3 months. The animals were weighted every two weeks, and their blood was drawn for hematological and liver function studies. Control animals showed a gradual increase in body weight from 17.8 +/- 1.1 g (SD) to 20.2 +/- 3.2 g during the 3 months of treatment. The body weight of 0.5 mg- and 2.5 mg-DSP group was not significantly different from that of the control group. In contrast, 5.0 mg-DSP group of animals showed significant decrease in their weight compared with the control after 5 weeks of treatment (P less than 0.01). They were then sacrificed. WBC in 0.5 mg-, 2.5 mg- and 5.0 mg-DSP groups were significantly lower compared with the control after 3 months of treatment. On the other hand, only 5.0 mg-DSP group showed significantly lower level in their RBC, Hb and Hct values (P less than 0.05). In contrast, platelet counts in 2.5 mg- and 5.0 mg-DSP group significantly increased. No manifest effect due to DSP on differential count of leukocytes was observed, although on day 92, a significant difference was shown in the stab cells of the 0.5 mg-DSP group and in the eosinophils in the 2.5 mg-DSP.(ABSTRACT TRUNCATED AT 250 WORDS)

Alanine Transaminase↗
PubMed1989

Subacute toxicity of (-)15-deoxyspergualin in BALB/c mice. II. Histopathological study.

Following the preceding report on hematological aspects in subacute toxicity of (-)15-deoxyspergualin (DSP), the present report dealt with the histopathological changes produced by DSP, 0.5-5.0 mg/kg, given to BALB/c mice for three months. At sacrifice, various internal organs such as heart, lungs, liver, spleen and kidneys, were taken, and their wet weights immediately measured. HE- or PAS-stained sections were histopathologically studied under light microscope. Additionally, frozen sections of the spleen were prepared to evaluate the effect of DSP on the lymphocyte surface markers like thy 1 and B220 by avidin-biotin complex (ABC) technique. Although the mean weights of lungs, liver, spleen and kidneys in the 0.5 mg- and 2.5 mg-DSP groups were not significantly different from those in the control animals, the weights of the heart, lungs, liver and spleen in the 5 mg-DSP group were significantly lower. Histopathological studies by light microscopy revealed no abnormalities in the heart, lungs, liver or kidneys taken from the mice given 0.5-5.0 mg/kg DSP. In contrast, significant changes were observed in the spleen and bone marrow of the 5.0 mg group of mice. Likewise, in the intestine of the 0.5-5.0 mg groups dose-dependent lesions, such as degeneration or disappearance of the mucosal epithelium, infiltration by inflammatory cells, and pseudo-membrane formation, was observed. By ABC technique, preferential decrease of B cells was seen in the splenic corpuscles of the DSP-treated mice. Histopathological changes due to DSP predominantly seen in the lymphoid and/or hematopoietic organs may be directly related to the immunosuppressive potency inherent to this drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Clinical experience of chemotherapy with cefmetazole for severe infections accompanying malignant hematological disorders].

We made an attempt to treat with cefmetazole (CMZ) 25 patients who developed severe infectious diseases while suffering with granulocytopenia associated with the treatment of malignant hematological disorders. 1. Determination of bacteriological efficacy While 20 strains were isolated and identified from 15 patients, no significant bacteria were detected in 9 patients. Isolates obtained were: 5 strains of Enterococcus faecalis, 3 strains of Haemophilus influenzae, 2 strains of Staphylococcus epidermidis, 2 strains of Klebsiella oxytoca, 2 strains of Staphylococcus aureus, and 1 strain each of Neisseria sp., Pseudomonas maltophilia, Enterobacter sp., alpha-Streptococcus, beta-Streptococcus and Gram-positive cocci. Causative organisms were eradicated or markedly in 7 of the 15 patients from whom bacteria were isolated. Clinical findings, including fever, revealed that none of the patients, in whom bacteriological efficacy was determined to be poor, exhibited sufficient clinical response. E. faecalis was isolated from 4 of 6 patients bacteriologically determined to have no response. 2. As for 23 patients, who were found to be evaluable among the 25 patients, 8 (34.8%), 4 (17.4%), 4 (17.4%), and 7 (30.4%) demonstrated excellent, good, fair and poor responses, respectively, showing a 69.6% efficacy rate which indicates a sum of percentages of patients with excellent, good and fair responses. 3. While an efficacy rate of 100% was obtained for 3 patients with number of peripheral neutrophils less than 500/mm3 before the beginning of CMZ administration, only an efficacy rate of 66.7% was obtained for 15 patients with neutrophils more than 500/mm3.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Relative strength of the mitogenic and interleukin-2-production-inducing activities of staphylococcal exotoxins presumed to be causative exotoxins of toxic shock syndrome: toxic shock syndrome toxin-1 and enterotoxins A, B and C to murine and human T cells.

Several observations suggest that staphylococcal enterotoxins A, B and C (SEA, SEB and SEC, respectively), in addition to toxic shock syndrome toxin-1 (TSST-1), are causative exotoxins of toxic shock syndrome (TSS). Based on the view that polyclonal T cell activation with the causative exotoxins, resulting in over-production of lymphokines, is involved in the development of the pathological changes observed in TSS, we investigated the activities of these four exotoxins to induce proliferation and interleukin 2 production in murine and human lymphocytes by using in vitro culture systems. The results showed that all these exotoxins are strong polyclonal inducers of proliferation and interleukin 2 production in human T cells, whereas TSST-1 and SEA are strong and SEB and SEC are weak polyclonal inducers in murine T cells. These results suggest that SEA, SEB and SEC, in addition to TSST-1, are possibly involved as causative exotoxins in the development of the pathological changes observed in TSS.

Adult↗
PubMed1988

Characterization of n-butyl alcohol solubilized, breast tumor specific antigens recognized by a human autologous cytotoxic T-cell clone.

We demonstrated previously the establishment of a human cytotoxic T-cell clone, TcHMC-1, under culturing with recombinant interleukin that showed the specific cytotoxicity against an autologous breast tumor cell line, HMC-1-8. In the present study, the autologous tumor specific antigens that could be involved in this cytotoxicity were extracted by using n-butyl alcohol and were analyzed for their biochemical profiles. The cytotoxicity of TcHMC-1 against HMC-1-8 was inhibited by adding OKT3 and OKT8 monoclonal antibodies into the cultures, or by pre-sensitizing HMC-1-8 target cells by anti-major histocompatibility complex class I monoclonal antibodies. This suggests that T-cell antigen receptor molecule complexes Ti/T3 on TcHMC-1 and corresponding specific tumor antigens on HMC-1-8 are involved in the cytotoxicity under the restriction of major histocompatibility complex class I products. Precultures of TcHMC-1 with crude n-butyl alcohol extracts from HMC-1-8 cells enhanced the cytotoxic potentials of this clone as seen as mixed lymphocyte tumor cell cultures. This enhancement was dependent on dosage of crude n-butyl alcohol extracts and these TcHMC-1 cells were still cytotoxic specifically for HMC-1-8 targets, but not for other allogenic tumor lines including K562. However, HMC-1-8 crude n-butyl alcohol extracts could not enhance DNA synthesis of TcHMC-1 as assessed by incorporation of [3H]thymidine in the cells. Biochemical purification studies demonstrated that the HMC-1-8 tumor specific antigens were eluted into fractions containing molecules with molecular weights of approximately 200,000 on Sephadex G-200 column chromatography. The antigens were further separated into the fraction that was eluted with 0.4-0.5 M NaCl in an ionic strength on Mono Q fast protein liquid chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of this fraction demonstrated three molecules with molecular weights of 26,000, 30,000, and 32,000 under reduced molecular conditions. The data suggest that these molecules could be tumor specific antigens that are involved in the cytotoxicity of cytotoxic T-cells against a human autologous tumor.

1-Butanol↗
PubMed1988

Identification of the transformation-associated cell surface antigen expressed on the rat fetus-derived fibroblast.

A WKA rat fetus-derived fibroblast cell line WFB showed strict nontransformant phenotypes in vitro such as anchorage dependency of cell growth in soft agar, contact inhibition, and serum dependency on the monolayer cell culture. Transfection of 6.6-kilobase EJras oncogene into WFB resulted in the acquisition of tumorigenicity in vitro and in vivo. The cell surface antigen that is moderately or highly expressed on these WFB transformants, designated as W14 and W31, was analyzed using monoclonal antibody 109 that was produced after the immunization of BALB/c mice with W31. Moab 109 recognized a glycoprotein with a molecular weight of 36,000 composed of a single polypeptide chain with 5.4 isoelectric point value. This antigen was highly expressed on WFB EJras and polyoma middle T-DNA transformants, but was undetectable or at the best only faintly recognized on WFB parental cells, transfectants of WFB with c-myc, and normal thymus, liver and kidney of WKA adult rats. It was also clearly expressed on the EJras transformants of Fisher rat fetus-derived 3Y1 fibroblast, but very faintly on parental 3Y1. Furthermore, this antigen was detected on some rat T-lymphoma and gliosarcoma lines. However, it was undetectable on EJras transformants on NRK-49F rat kidney cells and NIH3T3 and BALB3T3 mouse cells. In addition, this antigen appeared on the cell surface of concanavalin A-activated WKA rat lymphocytes and WKA rat on the 16th day of embryo but not on the 8th. These results suggested that the cell surface antigen detected by Moab 109 was clearly unrelated to the ras oncogene product p21 that was highly expressed on EJras-transformants of WFB or 3Y1 cells. Furthermore, it was shown that W14 and W31 cells but not parental WFB cells were susceptible to rat splenic NK cells that were induced by poly(I-C) treatment. Pretreatment of these W14 or W31 cells with Moab 109 could block the NK cell activity against W14 and W31. These data suggest that this antigen may act as one of the NK target structures, and plays an important role as a tumor antigen on the host tumor surveillance, since the antigen was expressed (a) on the cell surface after the cell transformation or enhanced DNA synthesis of some particular cells, and (b) in the W31 tumor developing progressively in the syngeneic rats.

Animals↗
PubMed1988

Glucose-6-phosphate stimulation of human muscle glycogen synthase phosphatase.

The influence of glucose-6-phosphate (glucose-6-P) on skeletal muscle glycogen synthase phosphatase was examined in normal glucose-tolerant Southwest American Indians. Phosphatase was stimulated with physiological concentrations of glucose-6-P and inhibited by ATP (5 mmol/L) and glycogen (0.1%). Phosphatase activity was measured before and after insulin infusion using the euglycemic clamp technique. Although glycogen synthase fractional activity increased in all subjects, this increase was not related to a change in phosphatase activity in the absence or presence of glucose-6-P. These results suggest that glycogen synthase phosphatase from human muscle can be regulated by physiological concentrations of glucose-6-P, ATP, and glycogen, and that insulin does not alter glucose-6-P stimulation of the enzyme in normal subjects.

Adenosine Triphosphate↗
PubMed1988

Lupus nephropathy in New Zealand F1 hybrid mice treated by (-)15-deoxyspergualin.

The effect of (-)15-deoxyspergualin (15-dsp), a new immunosuppressant which was originally separated from the culture filtrate of a strain of Bacillus laterosporus, was evaluated in this study. Various doses of 15-dsp were subcutaneously administered to New Zealand black/white F1 hybrid mice (B/WF1) four times a week starting at 14 weeks of age, just prior to the onset of nephropathy. The life span of the treated animals, studied at 0.6 to 6.0 mg/kg body weights, compared with the control mice was significantly prolonged by 15-dsp treatment (percent survival of the treated mice at 50 to 70 weeks of age was significantly higher than that of the control mice, except that of the 0.6 mg group at 60 wks of age, P less than 0.05 by Fisher's exact test). In the 6.0 mg group of mice, complete suppression of spontaneously progressive splenomegaly with decreased total spleen cells was observed at 24 through 36 weeks of age compared with the same-aged control group of mice (P less than 0.01). Absolute numbers of L3T4+ splenocytes determined by flow cytometry, as well as L3T4+/Lyt2+ ratio, were decreased, while in vitro interleukin 2 production by splenocytes induced with staphylococcal enterotoxin A was significantly enhanced. Serum IgG anti-ds DNA antibody levels, measured by radioimmunoassay in the treated mice, were significantly lower at 24 through 36 weeks of age than those in the control mice (P less than 0.01), and the incidence of significant proteinuria (greater than or equal to 100 mg/dl) in the 15-dsp group was lower at both 32 and 36 weeks of age (P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1988

The expression of tumor rejection antigen on rat fetus fibroblasts transformed by the ras oncogene.

The expression of tumor rejection antigens (TRA) was analyzed on clones of rat fetus-derived fibroblasts, WFB, transformed or transfected by oncogenes. It was shown that a tumorigenic W14 clone, which is an activated H-ras transformant of parental WFB, expressed TRA in transplantation experiments using syngeneic WKA rats. The data also showed that W14 TRA was acquired in the event of cell transformation, since it was not detected on parental non-transformed WFB cells or Wmyc-4 clone which is a transfectant of WFB by mouse plasmacytoma-derived c-myc DNA. However, TRA was not expressed or at least was not detected on highly tumorigenic W31, another clone of H-ras transformants of parental WFB, in the transplantation experiments. We also assessed the level of expression of major histocompatibility antigens (MHC) class I molecules on these cells by using R4-8B1 Mab that reacts specifically with rat class I antigen. The data indicated that it was decreased on W14, W31, and Wmyc-4, but not on parental WFB. Although this molecule was weakly positive on W14 cells, W31 and Wmyc-4 showed even greater decreases. These data may indicate that the TRA expression and its recognition by syngeneic hosts are dependent upon the transformed clones, although their parental cell is the same. We discuss in detail this difference of expression and recognition of TRA in the context of the cell transforming process.

Animals↗
PubMed1988

Impaired insulin-stimulated muscle glycogen synthase activation in vivo in man is related to low fasting glycogen synthase phosphatase activity.

Insulin-mediated glycogen synthase activity in skeletal muscle correlates with the rate of insulin-mediated glycogen deposition and is reduced in human subjects with insulin resistance. To assess the role of glycogen synthase phosphatase as a possible mediator of reduced glycogen synthase activity, we studied 30 Southwestern American Indians with a broad range of insulin action in vivo. Percutaneous biopsies of the vastus lateralis muscle were performed before and during a 440-min euglycemic clamp at plasma insulin concentrations of 89 +/- 5 and 1,470 +/- 49 microU/ml (mean +/- SEM); simultaneous glucose oxidation was determined by indirect calorimetry. After insulin stimulation, glycogen synthase activity was correlated with the total and nonoxidative glucose disposal at both low (r = 0.73, P less than 0.0001; r = 0.68, P less than 0.0001) and high (r = 0.75, P less than 0.0001; r = 0.74, P less than 0.0001) plasma insulin concentrations. Fasting muscle glycogen synthase phosphatase activity was correlated with both total and nonoxidative glucose disposal rates at the low (r = 0.48, P less than 0.005; r = 0.41, P less than 0.05) and high (r = 0.47, P less than 0.05; r = 0.43, P less than 0.05) plasma insulin concentrations. In addition, fasting glycogen synthase phosphatase activity was correlated with glycogen synthase activity after low- (r = 0.47, P less than 0.05) and high- (r = 0.50, P less than 0.01) dose insulin stimulations. These data suggest that the decreased insulin-stimulated glucose disposal and reduced glycogen synthase activation observed in insulin resistance could be secondary to a low fasting glycogen synthase phosphatase activity.

Adult↗
PubMed1988

Atrial natriuretic peptide in kidney of renal disease patients and healthy persons.

Regulation of renal excretion of atrial natriuretic peptide (ANP) was studied in kidney disease patients and healthy kidney donors. The measured ANP concentration in the patient's plasma did not correlate with their creatinine clearance (Ccr), while the fractional excretion of ANP (FEANP) significantly correlated with Ccr. FEANP in healthy persons is less than 1%. In the healthy donors of kidneys for transplantation, approximately 80% of the plasma ANP from the renal artery appeared in the renal vein. From these results, this high recovery of ANP in the veins does not appear to be adequately explained by its degradation in the renal arterioles and nephrons. The FEANP from kidney disease patients significantly correlated with FENa, FEK and FEP, but not with FECa and FEMg. The manner of ANP handling in the nephron may possibly differ from that of Ca or Mg.

Adolescent↗
PubMed1988

Cytotoxic T cell clones against human autologous cancers: analysis of target antigen and the mechanism of specific target cell destruction.

The human autologous pair of a cytotoxic T cell clone and tumor line could be very useful for the investigation of the specific destruction of autologous tumor cells by cytotoxic T lymphocytes (CTL), including analysis for tumor-specific antigen possibly of the rejection type, clonotypic T cell antigen receptors and biochemical characteristics of the cytotoxic molecules produced from CTL. We established such a pair of autologous specific CTL clone TcHMC-1 and target clone HMC-1-8 that were derived from the metastatic pleural effusion of a patient with mammary carcinoma. TcHMC-1 showed more than 60% specific cytotoxicity against HMC-1-8, and it was confirmed, using cold target inhibition assays, that this clone did not demonstrate nonspecific cytotoxicity against a allogeneic targets as well as the natural killer (NK) cell activity. We also confirmed the in vivo action of TcHMC-1 against HMC-1-8 cells by the Winn assay in nude mice. Using anti-CD3, 4, and 8 as well as anti-class I monoclonal antibodies (mAbs), it was demonstrated that T cell antigen receptor molecule complexes Ti/T3 on TcHMC-1 and corresponding specific tumor antigens on HMC-1-8 are involved in the cytotoxicity under the restriction of major histocompatibility complex (MHC) class I products. We developed mAb 3A2 reacting with the specific antigens on HMC-1-8 that could play an important role in this autologous pair. This mAb inhibited selectively the cytotoxic action of TcHMC-1 against HMC-1-8, and identified a molecule with approximately 92 kd m.w. 3A2-defined antigen was highly expressed on autologous primary breast carcinoma tissue, but not on normal mammary gland in the same patient. Moreover, this antigen can be detected on approximately 50% of human allogeneic breast carcinomas, but not on other neoplastic cells except for 1 out of 10 prostatic carcinomas. It was also suggested that 3A2-defined antigen is not murine mammary tumor virus-related antigen.

Animals↗
PubMed1987

Characterization of tumor rejection antigen molecules of chemically induced murine colon tumor C-C26.

The molecular nature of a tumor-specific transplantation antigen (TSTA) of a chemically induced BALB/c mouse colon tumor C-C26 was investigated. The antigen was noncytolytically extracted by 2.5% n-butanol treatment of the cells. Crude butanol extract from C-C26, but not from colon tumor C-C51 and fibrosarcoma Meth-A of BALB/c mice could provide protection against the challenged C-C26 tumor in the transplantation experiment. Crude butanol extract from another syngeneic colon tumor C-C36 also induced a cross-protection against the challenged C-C26 tumor. C-C26 crude butanol extract was characterized by biochemical procedures including the Sephadex G200 column, lens culinaris affinity column, and anion-exchange Mono Q fast protein liquid chromatography column, and by the enzyme digestion study of the antigens and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The data indicated that C-C26 TSTA was eluted into fractions containing molecules of approximately Mr 200,000 on Sephadex G200 column chromatography. This antigen was also found in unbound fractions on a lens culinaris affinity column. The antigen was further separated into the fraction that was eluted with 0.4 M NaCl in an ionic strength on Mono Q fast protein liquid chromatography. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of this fraction showed the molecule with a molecular weight of 30,000. The enzyme digestion study indicated that the immunogenicity of the antigen was inactivated by papain but probably not by neuraminidase treatment. These data suggest that the immunogenic moiety of C-C26 TSTA molecules is located in the peptide portions rather than in sialic acid residues or carbohydrate portions. Furthermore, there are several similarities of the molecular characteristics between C-C26 TSTA and previously reported C-C36 TSTA, such as the amenability to n-butanol extraction. Lens culinaris lectin inaffinity, and ionic strength.

Animals↗