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T Yasuda

Publications and source records attributed to T Yasuda.

At least 829 records · Page 46Linked to original sources
PubMed1986

Homogeneous determination of C-reactive protein in serum using liposome immune lysis assay (LILA).

Recently, we have developed an analytical system based on a complement dependent liposome immune lysis assay (LILA) to measure antibody against protein antigens. This paper describes the application of LILA to measure protein antigens by inhibition reaction. We choose human C-reactive protein (CRP), one of acute phase reactants, for a model of antigen determination. CRP antigen is coupled to the carboxyfluorescein entrapped multilamellar liposomes by using N-hydroxysuccinimidyl 3-(2-pyridyldithio) propionate and dithiothreitol, and a specific lysis of liposomes is achieved upon the addition of anti-CRP antibody in the presence of complement. Inhibition of this assay can be observed by the addition of competing amounts of CRP in human serum. This inhibition assay is simple, fast, highly sensitive, reproducible and homogeneous. The assay covers the ranges 10-500 micrograms/l. In an experiment using 50 samples, the results by LILA correlated well with those by single radial immunodiffusion and enzyme immunoassay (correlation coefficient: 0.99 and 0.93, respectively).

Antigens↗
PubMed1986

The effect of immunoglobulin G1 structure on macrophage binding to supported planar lipid monolayers.

We have studied the antibody-dependent binding of macrophages to supported planar lipid monolayers containing haptenated phospholipids (Tnp-Cap-DPPE). Eight monoclonal anti-TNP IgG1s, which had similar affinities to the TNP residues in solution and in the membranes, were used in the experiment. The results showed that mouse macrophages (P388D1 and J774.1) bound with different affinities to these IgG1-coated lipid monolayers. The monoclonal antibody shown to be deficient in macrophage binding was also relatively ineffective in activating complement. These results indicated that individual monoclonal antibodies of a given subclass may prove deficient in terms of the biological activities associated with the group as a whole.

Animals↗
PubMed1985

Functional role of cysteinyl residues in tryptophanase.

Holotryptophanase inactivated by oxidation of cysteinyl residues showed a different absorption spectrum from the native enzyme. At pH 8.0, the native enzyme preferentially existed as a 337-nm species (active form), whereas in the inactive enzyme a 420-nm species (inactive form) was dominant. During the reactivation of the enzyme by reduction with dithiothreitol, an increase at 337 nm and a decrease at 420 nm were observed with concomitant increase in enzymatic activity, which was accompanied by the appearance of two cysteinyl residues per monomer. Specific S-cyanylation of cysteinyl residues by nitrothiocyanobenzoic-acid-inactivated apotryptophanase with the modification of one cysteinyl residue per monomer, whereas holotryptophanase was highly resistant to inactivation with nitrothiocyanobenzoic acid. The essential role of the active-site-bound pyridoxal 5'-phosphate in protection against inactivation was confirmed by the agreement of the K1/2 (protection) of 5.0 microM for pyridoxal 5'-phosphate with Km of 2.0 microM in enzyme catalysis. The inactivation by nitrothiocyanobenzoic acid caused a similar shift in the equilibrium between the 337-nm species and 420-nm species, i.e. decrease of the 337-nm species and increase of the 420-nm species. From the pH dependence of the equilibrium between these two species, pKa of 7.9 and 7.4 was obtained for the inactive and the dithiothreitol-activated enzyme, respectively, indicating that cysteinyl residue(s) participated in lowering the pKa of the interconversion between the 337-nm species (active form) and 420-nm species (inactive form). The possible role of cysteinyl residues in the function of tryptophanase is discussed.

Catalysis↗
PubMed1985

Spontaneous glomerular IgA deposition in ddY mice: an animal model of IgA nephritis.

It was found that ddY mice derived from non-inbred dd-stock mice brought from Germany before 1920 and then raised in Japan developed spontaneously IgA dominant deposition in the glomerular mesangium. In this report we give a detailed natural history of the renal pathology of those mice. The animals were fed rodent laboratory chow and sacrificed in groups of 9 to 10 at 6, 10, 16, 24, 28, 40, and 59 weeks of age. The bladder urine was analyzed, serum immunoglobulins were measured, and the kidney specimens were evaluated with light, fluorescent, and electron microscopy. Proteinuria was (plus) to (2 plus) after 28 weeks and (2 plus) to (3 plus) at 59 weeks with negative hematuria. Mesangial cell proliferation began to appear at 16 weeks, then progressed to a definite proliferative glomerulonephritis. At 59 weeks an additional increase of the mesangial matrix occurred. By immunofluorescence, there were IgG of (2 plus), IgM (plus) to (2 plus), IgA (plus) and C3 (plus) in the glomeruli until 28 weeks. However, IgA started to be dominant at 40 weeks and the glomerular pattern was IgA (2 plus) to (3 plus), IgG (plus) to (2 plus), IgM (+/-) to (plus) and C3 (plus) to (2 plus) at 59 weeks. Polyclonal IgA and IgG2a among immunoglobulins steeply rose at 40 weeks, and at 59 weeks IgA increased by 850%, IgG2a by 280%, IgG1 by 170%, IgG2b by 90%, and IgM by 60%, as compared with their level at 6 weeks. There was no anti-nuclear antibody. Thus, ddY mice, at least after the age of 40 weeks, can be used as a new animal model for spontaneous IgA nephritis. The probable origin of IgA is also discussed.

Animals↗
PubMed1985

Structural requirements of lipid A responsible for the functions: a study with chemically synthesized lipid A and its analogues.

To confirm the revised lipid A structure of Escherichia coli and to establish the structure responsible for its functions, biological activities of the synthetic compounds based on the presented structure of E. coli lipid A were investigated. Compound 506, 2-deoxy-6-O-(2-deoxy-2-[(R)-3-dodecanoyloxytetradecanoylamino]-3-O [(R)3-tetradecanoyloxytetradecanoyl]-beta-D-glucopyranosyl]-3-O-[(R) -3-hydroxytetradecanoyl]-2-[(R)-3-hydroxytetradecanoylamino]-alpha -D-glucopyranose 1,4'-bis(phosphate), exhibited activities identical to those of natural E. coli lipid A in eliciting Shwartzman reaction and tests on lethality, pyrogenicity, interferon- and tumor necrosis factor-inducing activities as well as in B-cell activating activity and Limulus amebocyte lysate gelating activity. With the exception of the Shwartzman reaction the monophosphorylated synthetic compounds at either the 1 or 4' position showed slightly lower activities than the compound with the bisphosphorylated compound (Compound 506). The compound without the phosphate group showed no or only very weak activities. The structural requirements for each activity (i.e. binding position and composition of fatty acids and presence of phosphate groups) are discussed taking into account the results of previous investigations.

Animals↗
PubMed1985

Regional myocardial lidocaine concentration determines the antidysrhythmic effect in dogs after coronary artery occlusion.

Ischemic ventricular dysrhythmias were produced in 40 of 47 anesthetized mongrel dogs by high ligation of the left anterior descending coronary artery. Dysrhythmias were treated with a single iv bolus of 20, 40, 80, or 120 mg of lidocaine (L) in order to determine the dose at which approximately 50% of animals had an antidysrhythmic response. Cardiac output and regional myocardial blood flow (RMBF) were measured by using radionuclide labeled microspheres. Lidocaine concentration [( L]) was measured from samples of arterial and venous blood and normal and ischemic myocardium. All dogs treated with 40, 80, or 120 mg of L had an antidysrhythmic effect. However, with 20 mg of L the dysrhythmia persisted in 12 and resolved in 14. With 20 mg of L, ischemic myocardial [L] was greater in dogs with an antidysrhythmic effect than in those with persistent dysrhythmias (1.14 +/- 0.12 vs. 0.76 +/- 0.04 micrograms X g-1), but no difference was seen for arterial, venous, and normal myocardial [L]. Ischemic RMBF was higher in the dogs that had an antidysrhythmic effect than in those that did not, 9.8 +/- 1.5 versus 6.9 +/- 1.3% of normal. With 20 mg of L, [L] in ischemic myocardium correlated well with ischemic RMBF. The antidysrhythmic response to L had a threshold at a tissue concentration of greater than or equal to 1.0 microgram X g-1 (chi-square = 8.55, P less than 0.005). For this model, the [L] in ischemic myocardium during acute ischemia correlates with the antidysrhythmic response to L, while the concentration in normal myocardium or blood does not.

Animals↗
PubMed1985

Antiglycolipid antibodies in normal and pathologic human sera and synovial fluids.

Antiglycolipid antibodies were measured in normal and pathologic sera and synovial fluids by means of a modified microplate method of complement-mediated immune lysis of fluorescent dye-trapped liposomes. All sera of normal subjects had antibodies against globopentaosylceramide (IV3 GalNAcGbOse4Cer), ganglioside GM1, gangliotriaosylceramide, gangliotetraosylceramide, and galactosylneolactotetraosylceramide antigens. Most sera of normal subjects had antibodies against lactotriaosylceramide, N-glycolylneuraminosyl-neolactotetraosylceramide (NeuGcnLcOse4Cer), GM3 ganglioside with N-glycolylneuraminic acid (NeuGcGM3) and GD1a antigens. Differences of titers against IV3GalNAcGbOse4Cer, neolactotetraosylceramide, NeuGcGM3 and NeuGcnLcOse4Cer antigens were observed between sera of normal subjects and pathologic sera from cases of leukemias, lymphomas, several autoimmune diseases and liver diseases.

Adult↗
PubMed1985

Treatment of experimental salmonellosis in mice with streptomycin entrapped in liposomes.

Liposome-entrapped streptomycin (SM) was compared with free SM for therapeutic efficacy against experimental salmonellosis in mice. All of the mice infected with the virulent strain of Salmonella enteritidis 116-54 died between days 5 and 7, and a dose of 20 mg of free SM per kg administered 24 h after the bacterial inoculation did not prolong the survival. In contrast, the same dose of SM entrapped in liposomes prolonged paralleled the dose in the liposomes, and a dose as low as 1.2 mg of SM per kg in liposomes prolonged the survival. The advantage of using liposomes was more pronounced when a larger dose of SM was employed. The liposome-entrapped drug was less toxic than the free drug. A dose of 80 mg of free SM per kg caused convulsions, but the same dose entrapped in liposomes caused no side effects. Furthermore, two doses of liposome-entrapped SM further enhanced the therapeutic effect. The efficacy of the liposome-entrapped drug was still observed in mice infected with a large inoculum of S. enteritidis. A tissue distribution study on SM in various organs demonstrated that liposomal SM was selectively delivered to the spleen and liver with concentrations in these those in mice receiving the free drug. The prolongation of survival was due to suppression of the multiplication of S. enteritidis as demonstrated by viable cell counts in the spleens.

Animals↗
PubMed1985

Cephamycin inactivation due to enzymatic hydrolysis by beta-lactamase from Bacteroides fragilis.

The susceptibility of 53 clinical isolates of Bacteroides fragilis to cephamycins was examined. Judging from the MICs for 50% of the strains tested, moxalactam was the most active, however, judging from the MICs for 90% of the strains tested, cefbuperazone was more effective than moxalactam. A correlation was observed between in vitro activity of benzylpenicillin and cephaloridine and beta-lactamase production. Inactivation due to enzymatic hydrolysis of cephamycins over a short time was not observed; however, inactivation was detected by a double disk diffusion test, and moxalactam was most easily inactivated. We conclude that inactivation due to enzymatic hydrolysis of cephamycins over a long time may play an important role in resistance to some cephamycins in strains of B. fragilis.

Bacteroides fragilis↗
PubMed1985

Radioimmunoassay of bencyclane in human serum.

A radioimmunoassay of bencyclane in human serum was developed. Male rabbits were immunized with p-(3-carboxy-propoxy)bencyclane-bovine serum albumin conjugate, giving antisera with high titers. 125I-p-Hydroxybencyclane with a high specific activity was prepared as a labelled antigen by a chloramine-T method. In the radioimmunoassay procedure, a mixture of serum sample, diluted antiserum and 125I-antigen solution were incubated at 4 degrees C for 18 h, and bound-free separation was carried out by a dextran-coated charcoal method. The detection limit of bencyclane in human serum was 1.0 ng/ml, and the cross-reactivity of the antiserum with metabolites was found to be very low. Serum samples from healthy volunteers dosed orally with bencyclane fumarate were analyzed by both of the radioimmunoassay and gas chromatography-mass spectrometric methods. An excellent correlation was observed between the values obtained by both methods.

Animals↗
PubMed1985

Liposomes-mycobacteria incubation systems as a partial model of host-parasite interaction at cell membrane level.

The multilamellar lecithin-cholesterol liposomes entrapping carboxyfluorescence as a specific marker were prepared to be incubated with mycobacteria. The extent of resulting liposomal lysis was measured by marker release. Mycobacteria were highly active in this respect regardless of the species. Staphylococci were much less active and E. coli was completely inactive. Molecular species of lecithin and their ratio to cholesterol were related with the liposome sensitivity to mycobacteria. Ultrastructural and biochemical study showed that liposomes can be in close contact with mycobacteria and lecithins are degraded so that released fatty acids are incorporated into bacterial lipids, especially in virulent species. Liposomes-mycobacteria interaction was discussed as a partial model of the phagocyte-parasite interaction at the membrane level.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1985

Antibody-mediated alternative complement pathway activation resists inhibition by sialoglycolipids.

Although sialoglycolipids on liposome membranes were able to inhibit the activation of the alternative complement pathway (ACP) of guinea pigs mediated by trinitrophenylaminocaproyldipalmitoylphosphatidylethanolamine, they scarcely inhibited the ACP activation mediated by natural antibody to paragloboside (PG) inserted into the liposome membranes. Therefore, ACP activation was able to proceed regardless of the presence of sialoglycolipids on heterologous cell membranes when antibodies to constituents of the membranes were available. On the other hand, sialoglycolipids effectively inhibit undesirable ACP activation on self cell membranes, because little if any antibody is reacting on the self cell surface. Thus, the natural antibody reaction may effectively discriminate between self and non-self cell surface by cooperation with complement inhibitors on cell membranes such as sialoglycolipids.

Absorption↗
PubMed1985

Analysis of the mode of antigen presentation required for triggering of T cell proliferation by using various azobenzenearsonate-tyrosine derivatives.

Various azobenzenearsonate-tyrosine (ABA-Tyr) derivatives were synthesized by modifying amino and carboxyl groups at the alpha-carbon of tyrosine, with preservation of most of the ABA-Tyr moiety (ABA plus hydroxyphenyl portion of tyrosine). These derivatives were tested for the ability to stimulate ABA-L-Tyr specific T cell lines derived from B10.BR and B10.S mice. ABA-acetyltyramine, ABA-hydroxyphenylpropionic acid (ABA-PPr), and ABA-propylphenol, which lack either the carboxyl or amino group or both, could not induce T cell proliferation. The lack of stimulation by these derivatives was not due to their cytotoxic effects. A similar pattern of proliferation was obtained on stimulating lymph node T cells from B10.BR and B10.S mice primed with ABA-L-Tyr. Some differences were observed, however, between B10.BR and B10.S mice. ABA-L-Tyr-specific T cells from B10.BR mice could not respond well to ABA-D-Tyr in contrast to B10.S T cells. Furthermore, B10.BR mice primed with ABA-acetyltyramine or ABA-PPr in complete Freund's adjuvant could not induce ABA-L-Tyr-reactive T cells, whereas T cells from B10.S mice primed with these derivatives could proliferate in the presence of ABA-L-Tyr. The differences between B10.BR and B10.S mice were further investigated by using (B10.S X B10.BR)F1 mice. T cells from ABA-L-Tyr-immunized F1 mice responded poorly to ABA-D-Tyr when presented with B10.BR antigen-presenting cells (APC), but responded well when presented with B10.S APC. Similarly, T cells from ABA-PPr-primed F1 mice did not proliferate to ABA-L-Tyr in the presence of B10.BR APC, but could proliferate in the presence of B10.S APC. Our results clearly indicate that the presence of charged groups at the alpha-carbon of tyrosine plays a critical role in the triggering of ABA-L-Tyr-specific T cell proliferation. The significance of these results is discussed.

Animals↗