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Biomedical subjects

T Masuda

Publications and source records attributed to T Masuda.

At least 721 records · Page 40Linked to original sources
PubMed1983

Altered expression of lymphocyte Fc alpha receptor in selective IgA deficiency and IgA nephropathy.

To study the expression of FcR specific for IgA (Fc alpha R) on human peripheral lymphocytes (PBL), PBL from normal donors were incubated with 300 to 500 micrograms/ml MOPC 315 IgA having anti-trinitrophenyl (TNP) antibody activity at 4 degrees C or 37 degrees C for 60 min. Under this condition, less than 2% of total cells could form rosettes with TNP-coated ox red blood cells (TNP-ORBC). When cultured with MOPC 315 IgA at 37 degrees C for 18 hr, however, there was a dose-dependent increase of the rosette-forming cells (RFC) binding TNP-ORBC. Because 15 to 20% of the total cells bound TNP-ORBC but not unsensitized ORBC, the rosette formation appeared to be due to the cytophilic binding of IgA to the cells. The binding of MOPC 315 IgA was competed by TEPC 15 IgA and human myeloma IgA, but not by murine myeloma proteins of other classes, indicating that the receptor is specific for IgA. Fc alpha R was induced on 15 to 20% of fractionated T and B cells, as well as on 15 to 18% of concanavalin A-(Con A) activated lymphocytes when cultured with IgA. The induction of the receptor was dependent on protein and RNA synthesis, but not on DNA synthesis as suggested by the sensitivity to metabolic inhibitors, such as mitomycin C, actinomycin D, puromycin, and cycloheximide. In five patients with selective IgA deficiency (serum IgA, 0 to 4 mg/dl), only 5.1% +/- 1.7 of PBL formed rosettes with TNP-ORBC after culture with MOPC 315 IgA, whereas 12.5% +/- 2.5 of PBL from normal donors (serum IgA, 90 to 330 mg/dl) formed rosettes. Fc alpha R was induced on more than 15% of the cells from these patients, however, when cultured with IgA in the presence of a conditioned medium obtained from mixed lymphocyte culture from two normal donors. The results suggested that the abnormality in the patients' PBL might be in the induction mechanism rather than in the number of precursor cells that could express Fc alpha R in the presence of IgA. On the other hand, Fc alpha R was induced on 10.4% +/- 1.5 of PBL from the patients with IgA nephropathy (serum IgA, 382 +/- 11 mg/dl) when they were incubated with IgA for 1 hr at 37 degrees C. Because Fc alpha R on normal PBL was not induced by 1 hr of incubation with IgA, it appeared that the receptor was already expressed in vivo on the cells of these patients.

Animals↗
PubMed1983

Suppressive B-cell factor (SBF) produced by FcR-bearing B cells; suppression of B, but not non-B-cell proliferation.

B cells that have receptors for the Fc portion of IgG (FcR gamma + B cell) elaborate an immunoregulatory lymphokine termed suppressive B-cell factor (SBF) after binding immune complexes, such as sheep erythrocytes sensitized with IgG anti-sheep erythrocyte antibody (EA). For producing SBF, de novo protein is required, but not DNA or DNA-dependent RNA synthesis. This mediator is released into the culture supernatant of FcR gamma + B cells during 6 to 48 hr after stimulation by EA. SBF suppresses the proliferation of B, but not non-B cells. Thus, it suppressed (i) plaque-forming cell responses in the induction phase in an antigen-non-specific manner, (ii) DNA synthesis of lipopolysaccharide-activated B cells, but neither concanavalin A nor phytohaemagglutinin-activated T cells, and (iii) the proliferation of B but not non-B tumour-cell lines by acting at the G1-S junction in the cell cycle. Concordance of H-2 haplotype between SBF-producing mice and target B cells is necessary for the suppression. Thus, the action of SBF is B-cell specific and antigen-non-specific. Immune complex-mediated negative feedback regulation seems to be operated by lymphokines such as SBF which may be also involved in the surveillance for B-cell tumours.

Animals↗
PubMed1983

Monoclonal SBF produced by a hybridoma: in-vitro and in-vivo suppression of B tumour-cell proliferation.

A suppressive B-cell factor (SBF)-producing hybridoma termed TS-4.44 was established by fusion of B cells which possessed receptors for the Fc portion of IgG (FcR gamma + B cells) and thymidine kinase defective fibroblasts, 3T3-4E cells. The biological properties of hybridoma-produced SBF (Hyb-SBF) are almost the same as those of conventionally prepared SBF (Conv-SBF). Hyb-SBF suppresses (i) plaque-forming cell (PFC) responses in an antigen non-specific manner, (ii) DNA synthesis of lipopolysaccharide (LPS)-activated B cells, but neither concanavalin A (Con A) nor phytohaemagglutinin (PHA)-induced activation of T cells, and (iii) the proliferation of B, but not non-B tumour cells. Once absorbed with L-1210 cells, Hyb-SBF failed to inhibit both PFC and LPS responses. It is important is that Hyb-SBF suppresses the proliferation of L-1210 cells not only in vitro, but also in vivo. The physicochemical properties of Hyb-SBF such as sensitivity to trypsin, pronase and neuraminidase and its molecular weight (43,000), as judged by gel filtration and sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) are in accord with those of Conv-SBF. Moreover, it is eluted from a DEAE cellulose column with 0.1-0.3 M phosphate buffer. Thus, monoclonal SBF is thought to be identical with Conv-SBF and could provide us with sufficient material for the analysis of FcR-dependent immunoregulation including surveillance mechanisms controlling the proliferation of B tumour cells.

Animals↗
PubMed1983

Mannose-sensitivity and cross-reactivity with YAC-1 cells of cytotoxic T cells against syngeneic tumor cells.

Cytotoxic T lymphocytes (CTL) were raised against syngeneic plasmacytoma MOPC-315 cells by culturing spleen cells immunized with MOPC-315 cells 7 to 14 days previously, either in the presence or absence of MOPC-315 cells. The characteristics of these CTL were investigated in relation to those of natural killer (NK) cells. A portion of the CTL population cross-reacted with NK-sensitive YAC-1 cells. The cytotoxic activity of these CTL was blocked strongly by D-mannose and weakly by alpha-methyl-D-mannoside and glucose, but was not affected by galactose or N-acetyl-D-glucosamine. All of the above compounds blocked the activity of NK, but not that of CTL against allogeneic cells. Thus, these CTL have some similar properties to NK cells, but are clearly distinct from NK cells in the surface phenotype: asialo GM1 is positive in the membrane of NK, but negative in that of CTL. The mannose-sensitivity of the CTL activity was not observed when CTL to MOPC-315 cells were generated during the culture of twice-immunized spleen cells plus MOPC-315 cells. Furthermore, the activity of CTL obtained during the reculture of mannose-sensitive CTL with MOPC-315 cells was not blocked by mannose. These results suggest the existence of a maturation process of the CTL population to syngeneic MOPC-315 cells in terms of the sensitivity to D-mannose.

Animals↗
PubMed1983

Involvement of carbohydrate moieties in the expression of effector activity of cytotoxic T cells against syngeneic tumor cells.

Cytotoxic T lymphocytes (CTL) were raised against syngeneic plasmacytoma MOPC-315 cells by culturing spleen cells immunized with MOPC-315 cells 7 to 14 days previously, in the presence of MOPC-315 cells for 5 days. The cytotoxic activity of these CTL was blocked by D-mannose, indicating that mannose-containing carbohydrate moieties are involved in the expression of cytotoxic activity. Investigations were performed to determine which cells, effector or target, possess carbohydrate moieties, by employing procedures by which a part or most of the carbohydrate on cells can be removed. When target cells were treated with 2-deoxy-D-glucose, tunicamycin or trypsin, the levels of cytotoxic activity of the CTL were reduced. However, the reduced activities were still blocked by adding D-mannose at the effector phase. Treatment with alpha-mannosidase did not affect the level of cytotoxicity or mannose-sensitivity. In contrast, when effector cells were treated with tunicamycin by adding it to the culture one day before harvest, the level of cytotoxic activity was reduced, but the cytotoxic activity was no longer blocked by D-mannose. A similar result was obtained when effector cells were treated with periodate after 5 days of culture. However, the treatment of effector cells with alpha-mannosidase did not affect the cytotoxicity of the CTL. Thus, it was shown that effector cells possess mannose-containing carbohydrate moieties which are involved in the full expression of CTL to syngeneic MOPC-315 cells.

Animals↗
PubMed1983

[Statistical analysis of urinary estriol (U-E3), serum leucine aminopeptidase (LAP) and heat stable alkaline phosphatase (HSAP) in toxemia].

The levels of urinary estriol (U-E3), serum leucine aminopeptidase (LSP) and heat stable alkaline phosphatase (HSAP) were determined in toxemic and normal pregnancies. The significance of differences was established by weekly estimation of the parameters for both groups after the 28th week of gestation. Assayed values were classified into 4 types (type I-IV) by the mean values for 3 serial 24h assays and 3 patterns (pattern a-c) observed with these three determinations. The distribution rate for each type and pattern was examined according to the following: Severe toxemia, low birth weight, meconium staining at parturition and low apgar score groups. For U-E3, the incidence of the low value type (type IV) and the descending pattern (pattern c) both increased linearly in all the above groups. These findings suggest the clinical applicability of U-E3 as a reasonable indicator for evaluating intrauterine fetal well being because of the close correlation to the listed conditions. Thus these biochemical parameters should be considered in the antepartum fetal management of third trimester toxemic pregnancies.

Alkaline Phosphatase↗
PubMed1983

Changes in levels of translatable mRNA for neuron-specific enolase and non-neuronal enolase during development of rat brain and liver.

Neuron-specific enolase (NSE), and non-neuronal enolase (NNE) which exists in many tissues including liver but is localized in glial cells within the nervous system, were synthesized in the rabbit reticulocyte cell-free translation system programmed with brain mRNAs. The in vitro synthesized NSE and NNE were indistinguishable from the two enzymes purified from rat brains. NSE mRNA activity was found only in brain RNAs, while NNE mRNA activity existed in brain RNAs as well as liver RNAs. In developing brains, the level of translatable NSE mRNA was low at the embryonic stage and at birth, increased rapidly from about 10 days postnatal, and reached the adult level, while that of NNE mRNA was high at the embryonic stage and at birth, followed by a slight decrease then a gradual rise to adult levels. These changes correlated with the developmentally regulated appearance and accumulation pattern of each of the two enzymes. These results suggest that the levels of NSE and NNE are controlled primarily by the level of each of the two translatable mRNAs. In developing livers, only the NNE mRNA activity was detected and its level generally paralleled the changes in the level of NNE.

Animals↗
PubMed1983

A rapid separation of S100 subunits by high performance liquid chromatography: the subunit compositions of S100 proteins.

The subunits of S100 protein were dissociated and separated from each other by high performance liquid chromatography on a macroreticular poly-styrene resin, using an acetonitrile-trifluoroacetic acid solvent system. The separation was completed within 80 min in monitoring the effluent at 210 and 280 nm, allowing a rapid and sensitive identification of each S100 protein in terms of subunit composition, and a simultaneous purification of subunits. The method enabled to estimate the subunit compositions of S100a, S100b, and S100a0 protein purified from bovine brain, and revealed a micro-heterogeneity of S100 subunits as applied to the mixtures of S100 protein prepared from bovine, human and rat brain.

Amino Acids↗
PubMed1983

[A compact whole-body hyperthermia system utilizing extracorporeal circulation for anticancer treatment].

A compact whole-body hyperthermia system utilizing extracorporeal circulation for anticancer treatment has been devised and its clinical applicability is discussed. Our system has the following advantages; 1. Our small heat-exchanger made of polyvinyl-chloride hollow fibers exhibited sufficient heat-exchanging capability. 2. Our system is so compact as not to require priming with blood components. 3. Temporary blood access, created by direct puncture of the femoral vessels, eliminates vascular surgery and cardiac overload to the patients.

Body Temperature↗
PubMed1982

Phospholipid acyl chain metabolism during the differentiation of murine leukemia cell lines. On the redistribution of polyunsaturated acyl chains among phospholipids.

Phospholipid acyl chain metabolism was investigated during the differentiation of murine myeloid leukemic cells (MI cells). Fatty acid composition of the phosphatidylethanolamine (PE) fraction showed no significant change, while a marked decrease in the polyunsaturated fatty acid content was observed in the phosphatidylcholine (PC) fraction during the course of differentiation. When these cells were incubated with [14C]arachidonate, it was actively incorporated initially into PC, and subsequently, gradually mobilized to PE from PC during the 72 h of culture. This characteristic redistribution was observed specifically with polyunsaturated acyl chains. Thus, the normal metabolic pathway of polyunsaturated fatty acids in these cells appears to consist of two steps: firstly fatty acids are incorporated from the external medium into the form of polyunsaturated PC, and, subsequently, are stored within cells as a metabolically stable pool after the conversion into the form of polyunsaturated PE. In differentiated cells, this redistribution pathway was significantly enhanced, suggesting a change in the activity of the deacylation-reacylation cycle during the course of differentiation,

Animals↗
PubMed1982

Coupling factor.

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Animals↗
PubMed1982

Lysozyme dimer formation on lysozyme oxidation with Br2 radical as studied by fluorescence evolution.

Lysozyme dimers produced on oxidation of lysozyme with Br2 radical in aqueous solutions exhibit a fluorescence spectrum (lambda max = 400 nm) closely similar to that of bi-tyrosine. This suggests that the dimer is likely to have a tyrosine-tyrosine bond resulting from the combination of tyrosine phenoxy radicals of two lysozyme molecules. Kinetic studies on dimer formation were made by measuring time-dependent fluorescence after pulsed-electron irradiation over wide pH range. The results lead to the following conclusions. The second-order growth of the dimer fluorescence observed at pH 10.7-12.5 reflects the combination process of the lysozyme radicals, which is rate-determining in the pH range. On the other hand, the first-order growth observed at pH 6.8-10.2 is attributable to the enolization of the keto-form of the dimer. A tentative reaction scheme is proposed for the dimer formation.

Bromides↗