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T Yasuda

Publications and source records attributed to T Yasuda.

At least 901 records · Page 50Linked to original sources
PubMed1982

Activation of the alternative complement pathway of guinea-gip by liposomes incorporated with trinitrophenylated phosphatidylethanolamine.

By incorporation of trinitrophenylamino-caproyldipalmitoylphosphatidylethanolamine (TNP-Cap-DPPE) into liposomes composed of an equimolecular mixture of dimyristoylphosphatidylcholine (DMPC) and cholesterol (TNP-Cap-liposomes), liposomes became readily lysed by guinea-pig serum (GPS) in Mg++-EGTA-GVB (gelatin veronal buffered saline containing 2 mM MgCl2 and 10 mM ethyleneglycol-bis (beta-amino-ethyl ether)N-N'-tetraacetate) as well as in GVB++ (gelatin veronal buffered saline containing 0.15 mM CaCl2 and 0.5 mM MgCl2). Since the classical complement pathway (CCP) does not work in Mg++-EGTA-GVB, TNP-Cap-liposome lysis by GPS in Mg++-EGTA-GVB was thought to be mediated by the activation of the alternative complement pathway (ACP). This conclusion was supported by observations that heating of GPS at 50 degrees impaired its lytic activity while C4-deficient GPS was capable of lytic activity, no lysis occurred in EDTA, and there was noted consumption of complement in GPS treated with TNP-Cap-liposomes at 30 degrees. For TNP-Cap-liposome lysis by GPS in Mg++-EGTA-GVB, the epitope density of the TNP hapten was required to be 5% or more of the DMPC. Changing the acyl group of the phosphatidylcholine (PC) significantly influenced the ACP activating capacity of TNP-Cap-liposome. Dipalmitoyl-PC, DMPC and distearoyl-PC facilitated the ACP activating capacity of the TNP-Cap-liposome, while dilauroyl-PC, egg-PC and dioleoyl-PC did not. Furthermore, the length of spacer between TNP and dipalmitoylphosphatidylethanolamine (DPPE) also influenced the ACP activating capacity and maximum activation was noted when the spacer was aminocaproyl. These physicochemical characteristics which increase the ACP activating capacity coincided with those reported to increase the immunogenicity of hapten-sensitized liposomes.

Animals↗
PubMed1982

[Pharmacokinetic studies of piperacillin after 4 g or 8 g intravenous injection in human healthy volunteers].

The pharmacokinetics of piperacillin (PIPC) after intravenous injection of 4 g and 8 g was studied on healthy volunteers, and the following results were obtained. 1. Serum concentrations of PIPC were measured, and simulation curves were obtained by using 2-compartment model. PIPC has been found to produce higher serum level soon after intravenous administration and it was rapidly eliminated. 2. In the view of pharmacokinetic parameter and peripheral compartment level of PIPC, it was estimated that distribution of PIPC of various tissues was prompt after administration. 3. PIPC was excreted rapidly, and approximately 100% excretion was observed up to 8 hours after instillation of 8 g PIPC for 2 hours. No accumulation of PIPC was noted.

Adult↗
PubMed1982

Effect of lipid A incorporation on characterization of liposomal model membranes as thymus-independent type 1 or type 2 immunogens.

We used the following criteria to determine whether liposomal model membranes are thymus-independent type 1 (TI-1) or type 2 (TI-2) immunogens: a) in vivo response of (CBA/N X BALB/c)F1 male and female mice; b) in vitro response of spleen cells from these mice; c) ontogeny of the response in cultures of (C57BL/6 X DBA/2)F1 male cells obtained from mice of different ages; d) ability of a monoclonal anti-delta antibody to block the in vitro response of C57BL/6 spleen cells. The liposomes were sensitized with N(2,4,6-trinitrophenyl-6-N-aminocaproyl)-dipalmitoylphosphatidylethanolamine (TNP-Cap-DPPE) and were prepared without and with incorporation of the B cell mitogen, lipid A. On the basis of the above criteria, liposomes prepared without lipid A can be characterized as a TI-2 immunogen and resemble TNP-Ficoll. In contrast, liposomes prepared with lipid A behave like a TI-1 immunogen such as TNP-BA (trinitrophenylated Brucella abortus). Conversion of liposomes from a TI-2 to a TI-1 immunogen by inclusion of lipid A in the bilayers was achieved under conditions of constant TNP-Cap-DPPE epitope density. Increasing the epitope density in liposomes made without lipid A does not result in transformation of immunogen type. These results, which bear on the features that may distinguish TI-1 from TI-2 immunogens, are discussed with regard to the involvement of macrophages and T cells in the response.

Animals↗
PubMed1982

Effect of hyaluronidase on experimental cerebral infarct size and mortality.

The goal of this investigation was to determine whether hyaluronidase administration can alter the size, morbidity, and mortality of experimental acute cerebral infarctions. Accordingly, the left common carotid artery was occluded in 1205 ether-anesthetized Mongolian gerbils. The gerbils were randomized into hyaluronidase-treated (4000 National Formulary units per kg., intravenously, 5 minutes after occlusion) or control groups. All were examined for clinical signs of cerebrovascular accident three times during the 24 hours and then decapitated, and each hemibrain was analyzed for its total creatine kinase activity. In the control group, 90 of 601 gerbils died, whereas in the hyaluronidase-treated group only 61 of 604 gerbils died. This reduction in mortality was highly significant (chi 2 = 6.53, p less than 0.02). In the surviving gerbils with cerebrovascular accidents, infarct size was calculated by creatine kinase depletion (normal right hemibrain creatine kinase minus infarcted left hemibrain creatine kinase divided by right hemibrain creatine kinase and corrected for "residual" (nondepletable) creatine kinase). In controls, infarct size was 36.5 +/- 1.8 per cent (n = 105), and in the hyaluronidase-treated gerbils it was significantly lower, 31.4 +/- 1.7 per cent (n = 117, p less than 0.05). Thus, in gerbils with experimental cerebrovascular accidents, hyaluronidase significantly reduced mortality (by one-third) and reduced "enzymatic" infarct size by 14.0 +/- 4.6 per cent (p less than 0.01).

Animals↗
PubMed1981

A simple method to measure anti-glycolipid antibody by using complement-mediated immune lysis of fluorescent dye-trapped liposomes.

A simple, reproducible, and micro quantity method is described to measure the antibody against glycolipid antigens. The multilamellar liposomes containing carboxyfluorescein (CF), which is self-quenched at high concentration, are prepared by vortexing the dried lipid films consisting of egg lecithin, cholesterol, phosphatidic acid and Forssman glycolipid antigen. On addition of anti-glycolipid serum plus active complement, liposome lysis occurs, and trapped CF is released. The dilution of CF in the external volume abolishes the quenching, resulting in a high fluorescence signal. Experimental conditions to measure anti-glycolipid antibody is established in this paper.

Animals↗
PubMed1981

Experimental allergic encephalomyelitis induced by basic protein with synthetic adjuvant in comparison with Freund's complete adjuvant. Role of antibodies in correlation with the clinicopathological features.

Experimental allergic encephalomyelitis (EAE) was induced in guinea pigs with bovine myelin basic protein (BP) with adjuvant of either synthetic muramyl dipeptide (Mdp) or Mycobacterium tuberculosis (Tbc). The following results were obtained: (1) The body temperature of the animals was studied serially after sensitization and its elevation was shown to be an early sign of EAE. (2) Several animals developed the clinical and histological signs of hyperacute EAE. (3) An optimal combined dosage of BP and adjuvant was found for induction of clinical EAE and for the the production of complement fixing (CF) antibodies. (4) Little passive hemagglutinating (PH) antibody was produced by single immunization. These results displayed no essential difference in EAE induced by either adjuvant. (5) Detectable PH antibodies developed later in addition to CF antibodies in a few animals immunized with Tbc adjuvant. These animals were skin-tested to BP, and had recovered from body weight loss or limb weakness. The results suggest that humoral antibodies play a role in modifying the disease process, even if they are not essential in production of EAE.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1981

An electron microscopy study of intra-cellular mycobacteria in experimental mouse tuberculosis.

Ultra-thin sections for electron microscopy (EM) were prepared from granulomatous lungs which developed in mice in response to experimental infection by a highly virulent strain of M. bovis. A subsidiary study was made of the EM appearance of mycobacteria separated from the lung tissue homogenate by differential centrifugation and trypsin-digestion. Examination of many micrographs showed that the phagosomal membrane may, at least partly, be in close contact with the cell wall of ingested mycobacteria. Such areas of contact often produce an electron-dense granularity or a row of evenly-spaced minute granules, accompanying the damage to the inner structure of the bacterial cell. A variety of disintegrating bacterial figures were observed, characterized by inward detachment of the plasma membrane, shrinkage and digestion of the cytoplasm, and occasional rupture of the cell wall. Various forms of lamellated and osmophilic inclusion bodies were present in macrophages, but their relation to ingested mycobacteria was uncertain.

Animals↗
PubMed1981

Asymmetric division of immature lymphoid cells of the embryonic mouse thymus.

Cell division of thymus lymphoid cells from 15- to 19-day-old embryonic mice, as well as from 2- and 7-day-old mice was investigated on cell smears stained with Giemsa or with the Feulgen reaction followed with malachite green. Asymmetrically dividing cells were observed during the development. At the anaphase and telophase of such cells, the nucleus of one of two immature daughter cells was apparently smaller and more condensed than that of the counterpart cell. The asymmetry was already apparent at the level of sister chromosomes at anaphase. Sometimes a difference also existed in the cytoplasm: the cytoplasm of the smaller immature daughter cell with condensed nucleus was stained with Giemsa more deeply than that of the counterpart. The frequency of cells displaying apparent asymmetric division among total dividing cells at the telophase was around 10% between 15 and 19 days of gestation, and decreased to 2% on days 2 and 7 after birth. Asymmetrically dividing cells belonged to immature lymphoid cells of larger size. The biological implications of the present phenomenon are discussed.

Animals↗
PubMed1981

Studies on protein binding of antibiotics. II. Effect of apalcillin on protein binding and pharmacokinetics of cefoperazone and cefazolin.

The drug-protein interactions between cefoperazone (CPZ) and apalcillin (APPC), and between cefazolin (CEZ) and APPC were investigated in in vitro and in vivo experiments. Through the binding rates of CPZ or CEZ to rabbit serum and human serum albumin subsided remarkably with increased drug concentrations, APPC was not greatly affected, even at high concentrations. It appeared that APPC had a higher binding capacity to protein than CPZ or CEZ. From the results of competitive study, it became clear that APPC partially shared the binding sites on protein with CPZ or CEZ. The CPZ or CEZ serum levels in rabbits administered together with APPC were not different from those for the single administration, but APPC levels for the simultaneous administration were slightly lower.

Ampicillin↗
PubMed1981

Studies on protein binding of antibiotics. III. Effect of novobiocin on protein binding and pharmacokinetics of cefoperazone and cefazolin.

The drug-protein interactions between cefoperazone (CPZ) and novobiocin (NB), and between cefazolin (CEZ) and NB were investigated. Though there was a remarkable reduction of CPZ or CEZ binding to rabbit serum and human serum albumin with increases in drug concentrations above 3.0x10-4M (CPZ: 200 microgram/ml, CEZ: 140 microgram/ml), NB binding was not affected. In addition, when CPZ or CEZ was added to the NB solution, NB binding was not altered and remained above 90%. Therefore, it was evident that NB had a high capacity for binding to protein, compared with CPZ or CEZ. From the competitive study, the main binding site of NB to protein appeared to differ from that of CPZ or CEZ. The CPZ or CEZ serum levels in rabbits for the simultaneous adminstration of NB were significantly higher than those for the control experiments, however, the NB serum levels were not greatly affected by CPZ or CEZ.

Animals↗