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Biomedical subjects

T Shiba

Publications and source records attributed to T Shiba.

At least 199 records · Page 11Linked to original sources
PubMed1986

Induction of human interleukin 1 by bacterial and synthetic lipid A.

Lipopolysaccharides (LPS) are well known inducers of interleukin 1 (IL 1). Here we show that synthetic heptaacyl Salmonella minnesota (compound 516) and synthetic E. coli type (compound 506) lipid A, as well as monodephospho part structures thereof, are able to induce IL 1 production in human mononuclear cells. The 4'-monodephospho part structure (compound 505) was found to be the most active IL 1 inducer as compared to compound 506 and the 1-monodephospho part structure (compound 504). Synthetic lipid A precursor Ia, lacking nonhydroxylated fatty acids (compound 406), and its 1- or 4'-monodephospho part structures (compounds 404 and 405) did not induce IL 1 production. IL 2 is not produced during stimulation with the synthetic compounds. IL 1 activity was partially heat labile and could be inhibited by a rabbit antiserum against human leukocytic pyrogen. These results show that the lipid A component of LPS is active in inducing IL 1 and that the presence of 3-acyloxyacyl residues is necessary for IL 1 induction.

Blood Physiological Phenomena↗
PubMed1986

Effectiveness of liposomes as potential carriers of vaccines: applications to cholera toxin and human malaria sporozoite antigen.

Two antigens, cholera toxin (CT) and a synthetic albumin-conjugated 16-residue peptide derived from the circumsporozoite (CS) protein of Plasmodium falciparum sporozoites, were tested as immunogens in rabbits. The malaria peptide-albumin conjugate by itself was completely nonimmunogenic, and although cholera toxin was immunogenic it also expressed considerable native toxicity. After attachment of CT to liposomes containing ganglioside GM1, toxicity of CT was completely eliminated and antigenicity was enhanced. Therefore liposomes may be capable of reducing toxicity of certain potentially dangerous antigens such as toxins. After incorporation of the malaria peptide-albumin conjugate into liposomes a high titre of specific antibodies was induced against the malaria peptide but not against albumin. These antibodies also reacted with native CS protein. Three adjuvants, including lipid A and two types of lipophilic muramyl dipeptide, were compared and found to be effective in liposomes. Based on the conversion of synthetic P. falciparum CS peptide from a nonimmunogenic to an immunogenic form and on the 'toxoiding' effect of liposomes for CT, it is concluded that liposomes should be considered as being a useful carrier for antigens and adjuvants for vaccines for poorly antigenic or toxic substances.

Adjuvants, Immunologic↗
PubMed1986

Adjuvant and antitumour activities of synthetic lipid A analogues.

The biological activities of synthetic glycolipids, which were chemically synthesized and based on the structure of lipid A of the lipopolysaccharide (LPS) from Escherichia coli, were examined with special reference to their adjuvant activity on the induction of delayed-type hypersensitivity, activity on the induction of tumour necrotic factor (TNF) and tumour regressive activity on line 10 hepatoma in strain 2 guinea pigs. Among them, a compound structurally corresponding to free E. coli lipid A (compound 506) as well as LPS exhibited potent adjuvant activity in the induction of delayed-type hypersensitivity in guinea pigs and TNF inducing activity in the sera of mice which were presensitized with Propionibacterium acnes. Compound 506 showed potent lethal toxicity in the intravenous administration of BALB/c mice presensitized with P. acnes. The regressive activity on line 10 hepatoma was observed by the multiple intralesional injection of squalane-treated compounds 504 and 505 in strain 2 guinea pigs.

Adjuvants, Immunologic↗
PubMed1986

Sequence of 3000 nucleotides at the 5' end of Japanese encephalitis virus RNA.

The 5' region of the Japanese encephalitis virus (JEV) RNA was cloned and 3000 nucleotides (nt) were determined by sequencing DNA complementary to viral RNA, and genomic RNA, using oligodeoxynucleotide primers and the dideoxy chain-termination reaction. Comparison of the nt sequence and the reduced amino-acid sequence of JEV with those of other flaviviruses showed significant homologies, which allowed locations to be assigned for three structural proteins.

Base Sequence↗
PubMed1986

Identification of a sequence containing the positive regulatory region of Saccharomyces cerevisiae gene ENO1.

A DNA fragment which contains the 5'-flanking region of the Saccharomyces cerevisiae enolase 1 gene (ENO1) and a portion of the coding sequence was cloned in a plasmid pMC1587. This fragment was fused in frame to the lacZ gene of Escherichia coli. Many mutants which deleted a portion of the 5'-flanking region of ENO1 were isolated from this ENO1-lacZ fusion plasmid by in vitro recombination. Analysis of beta-galactosidase activity of these mutants indicated that the regulatory region responsible for an efficient expression of the ENO1-lacZ fused gene resides within an 86-bp sequence located at -487 to -402 upstream from the start codon of ENO1. We found that the segment encompassing the 86-bp region worked equally well in an inverted orientation, but the tandem duplication of the sequence did not enhance the expression of the fused gene.

Bacterial Proteins↗
PubMed1986

Structure-activity relationship of lipid A: comparison of biological activities of natural and synthetic lipid A's with different fatty acid compositions.

To investigate the structure-activity relationships, various biological activities, including pyrogenicity, lethal toxicity, elicitation of Shwartzman reaction, mitogenicity and tumor necrosis factor (TNF)-inducing activity, were compared among natural and synthetic lipid A's differing in fatty acid composition. In all these tests, natural lipid A's from Escherichia coli and Salmonella minnesota and synthetic LA-15-PP, which carries 3-hydroxy- and 3-acyloxy-tetradecanoyl groups at the 2, 3 and 2', 3' positions, respectively, showed the strongest activities among the tested lipid A's. In contrast, LA-16-PP, in which the amide-bound 3-hydroxytetradecanoic acid at position 2 of LA-15-PP is replaced by 3-hexadecanoyloxytetradecanoic acid, exhibited lower activity than LA-15-PP and natural lipid A's. Although LA-16-PP has been assumed to have a typical Salmonella lipid A structure (and, in fact, it has a structure corresponding to one of the components of Salmonella lipid A), the activity of this synthetic compound was not comparable to that of natural Salmonella lipid A. LA-17-PP, in which tetradecanoic acid is the sole fatty acid component, exhibited relatively strong mitogenicity and TNF-inducing activity, but very low pyrogenicity. The activities of LA-18-PP, which has ester-bound tetradecanoic acid and amide-bound 3-hydroxytetradecanoic acid, were lower than those of LA-17-PP. The results indicate that the differences in fatty acid composition of lipid A's have important influences on the biological activities studied.

Animals↗
PubMed1986

Enhancement of anti-inflammatory effects of biphenylylacetic acid by its incorporation into lipid microspheres.

Using lipid microspheres (LM), average diameter 0.2 micron, and containing methyl and ethyl esters of biphenylylacetic acid (BPAA) in the carrageenan paw oedema tests in rats, it was found that their anti-inflammatory activities were enhanced 3 to 8 times over that of free BPAA. By electron microscopy, LM were seen to be taken up into the endothelial cells of the blood vessels and macrophages at the inflamed sites. In a study using dogs, after an intravenous injection of BPAA-methyl ester incorporated into LM (lipo-BPAA-Me), lipo-BPAA-Me rapidly disappeared from the blood and the BPAA serum level was gradually elevated. These results, together with previous findings, suggest that part of lipo-BPAA-Me was immediately transferred to the inflamed site and taken up by prostaglandin (PG)-producing cells as macrophages. It is considered that the anti-inflammatory effects of BPAA are enhanced by incorporating it into LM.

Animals↗
PubMed1986

Immunogenicity and antigenicity of synthetic Escherichia coli lipid A.

The immunogenicity and antigenicity of synthetic Escherichia coli lipid A (compound 506) and its 1- and 4'-monophosphorylated derivatives (compounds 505 and 504, respectively) and nonphosphorylated derivative (compound 503) were compared with those of bis- and 4'-monophosphorylated natural free lipid A from E. coli. The synthetic compounds under study were either coated onto sheep erythrocytes (except for the water-insoluble preparation 503) or incorporated into liposomes and used for the immunization of rabbits. Both types of immunogens (the latter representing fully synthetic immunogens) resulted in high-titered polyclonal antisera which were characterized before or after absorption in a passive hemolysis assay as well as in a passive hemolysis inhibition assay with the synthetic compounds as test antigens. All antisera were found to react with their corresponding homologous antigens coated onto sheep erythrocytes, with titers of up to 2,048, and were comparable to those antisera obtained after immunization with natural lipid A exposed on the bacterial surface after acid hydrolysis. Antisera against bisphosphorylated compound 506 were highly specific for the homologous antigens, showing no interaction with compounds 504 and 505 in the passive hemolysis test. The same held true for the absorption experiments in which glutaraldehyde-fixed sheep erythrocytes were sensitized with the respective antigens. Antisera against monophosphorylated compounds 504 and 505 exhibited, besides their expected homologous reactivity, complete cross-reactivity with compound 506, but they did not cross-react with each other. Thus, anti-504 and anti-505 antibodies recognized distinct antigenic determinants, being related to the ester linked 4'-phosphate or the glycosidically linked 1-phosphate, respectively. Both antigenic determinants were also expressed by bisphosphorylated compound 506 used as an antigen; however, upon immunization, only antibodies against compound 506 were elicited.

Epitopes↗
PubMed1986

Synthetic Salmonella-type lipid A antigen with high serological specificity.

A synthetic compound (compound 516), beta(1-6)-linked D-glucosamine disaccharide 1,4'-bisphosphate, which is acylated by (R)-3-hexadecanoyloxytetradecanoyl, (R)-3-hydroxytetradecanoyl, (R)-3-dodecanoyloxytetradecanoyl, and (R)-3-tetradecanoyloxytetradecanoyl groups at positions 2,3,2', and 3', respectively, exhibited in vitro antigenic reactivity of high specificity comparable to that of free lipid A from Salmonella minnesota R595. This was confirmed by an enzyme-linked immunosorbent assay and an enzyme-linked immunosorbent assay inhibition test with monoclonal and conventional antibodies. The results of comparative analysis performed with several synthetic lipid A analogs as well as three monosaccharide derivatives suggested that the complete structure involving both phosphate groups at the C-1 and C-4' positions and the 3-acyloxyacyl groups at the C-2, C-2', and C-3' positions of the glucosamine disaccharide are required for the expression of the serological specificity of Salmonella-type lipid A. This was deduced from the observations that compound 506, a synthetic Escherichia coli-type lipid A which has the same structure as that of compound 516, except that 3-hydroxytetradecanoyl group is substituted for an acyloxyacyl residue at the C-2 position, exhibited significantly reduced antigenic reactivity as compared with compound 516 and that the replacement by the hydrogen atom of the phosphoryl group at the C-1 position or by 3-hydroxytetradecanoyl or tetradecanoyl groups of acyl residues at the 2, 3, 2', and 3' positions of compound 516 results in a marked reduction of reactivity with monoclonal antibodies 5G and 36G. Similar results were obtained by assays with conventional rabbit antibodies, but the structural difference between compounds 516 and 506 could not be distinguished by these polyclonal antibodies. The results of cross-reactions among synthetic analogs with monoclonal antibodies 161M and 1-9M, which have been confirmed to exhibit different serological specificities from the 5G or 36G antibody, also suggested that the nature and linkage of fatty acyl residues as well as the backbone structure of lipid A play an important role in determining serological specificity of the lipid A molecule.

Antigens, Bacterial↗
PubMed1986

Adjuvant activity of 6-O-acyl-muramyldipeptides to enhance primary cellular and humoral immune responses in guinea pigs: adaptability to various vehicles and pyrogenicity.

Thirteen 6-O-acyl-N-acetylmuramyl-L-alanyl-D-isoglutamines (6-O-acyl-MDPs), including four inactive D-isoasparagine and L-isoglutamine analogs, were tested for their pyrogenicity and immunopotentiating activity to stimulate primary humoral and cellular immune responses in guinea pigs to a model protein antigen, ovalbumin, when administered in various vehicles. Among them, derivatives whose muramic acid residue was substituted by alpha-branched (and beta-hydroxylated) higher fatty acids at the carbon-6 position, especially 6-O-(2-tetradecylhexadecanoyl)-MDP (B3O-MDP) and, to a lesser extent, 6-O-(3-hydroxy-2-docosylhexacosanoyl)-MDP (BH48-MDP) and its L-serine analog [BH48-MDP(L-Ser)], were found to exert strong adjuvant activity in both the induction of delayed-type hypersensitivity and the stimulation of circulating precipitating antibody levels when combined with nonirritating vehicles (liposomes, squalene-in-water emulsion, and phosphate-buffered saline). These vehicles did not efficiently support the adjuvant activity of MDP, the parent molecule of the above lipophilic derivatives. Pyrogenicity tests showed that introduction of alpha-branched higher fatty acid groups but not of straight, long-chain fatty acids at the 6-position of the muramic acid residue resulted in marked decrease of the pyrogenicity inherent to MDP via intravenous administration.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1986

Adjuvant activity of 6-O-acyl-muramyldipeptides to enhance primary cellular and humoral immune responses in guinea pigs: dose-response and local reactions observed with selected compounds.

6-O-(2-Tetradecylhexadecanoyl)-N-acetylmuramyl-L-alanyl-D-isoglutamine (B3O-MDP) and 6-O-(3-hydroxy-2-docosylhexacosanoyl)-MDP (BH48-MDP) were examined for immunopotentiating activity in stimulating the primary immune responses of guinea pigs to ovalbumin and for adverse reactions at the injection site and in the regional lymph nodes when administered in combination with several nonirritating vehicles. B30-MDP was found to potently stimulate both humoral and cellular immune responses, the latter by induction of delayed-type hypersensitivity, irrespective of the administration vehicle examined (liposomes, a squalene in water emulsion, Intralipid, phosphate-buffered saline, and Nikkol HCO-60 glucose solution), although the minimum effective dose was dependent on the vehicle used. Reactions in the footpad receiving the injection were negligible. Noticeable local reaction consisted of swelling of the lymph nodes in the region of the injection, but the swelling was only noted with higher doses and subsided 3 to 4 weeks after immunization, unlike the persistent swelling caused by the administration of water-in-mineral oil emulsions with or without B30-MDP. BH48-MDP and its L-serine analog, BH48-MDP(L-Ser), which has L-serine in place of L-alanine in MDP, in combination with the squalene-in-water emulsion, also intensely stimulated both cellular and humoral antiovalbumin immune responses, but the effects of these compounds seemed to be influenced to a greater degree by the vehicles than by B30-MDP. Thus, B30-MDP was chosen from a series of a 6-O-acyl derivatives of MDP as the most promising candidate for possible application in practical vaccines.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1986

Familial disorder with increased number of insulin receptors: a new category of insulin receptor abnormality.

We found a family in which 6 of 13 family members had extremely high insulin binding to their erythrocytes. The specific binding values of these patients were 3- to 4-fold higher (22.8-28.6% of added [125I]insulin) than normal (mean +/- SD, 7.1 +/- 0.8%; r = 44). Scatchard analysis revealed that in each patient increased insulin binding was due to increased binding capacity, with little change in affinity. In all patients, reticulocyte counts were within the normal range. From the pedigree analysis, the pattern of inheritance was considered to be autosomal dominant. The propositus was more extensively studied. His mononuclear leukocytes and Triton X-100-solubilized preparations of erythrocyte ghosts also had high (approximately 3-fold) insulin-binding capacity compared to that of normal subjects. In contrast, the number of ouabain-binding sites and kinetics of sugar transport were normal. From these findings, we propose a new type of inherited abnormality of the insulin receptor.

Adult↗
PubMed1986

Aerobic photosynthetic bacteria.

Erythrobacter species OCh 114 is a strictly aerobic bacterium containing bacteriochlorophyll a. Although its growth is dependent on heterotrophic nutrition, light enhances its growth yield and CO2-fixation activity. A new category--aerobic photosynthetic bacteria--is proposed for Erythrobacter species OCh 114.

Aerobiosis↗
PubMed1985

N tau-Ribosylhistidine, a novel histidine derivative in urine of histidinemic patients. Isolation, structure, and tissue level.

On amino acid analysis of urine of histidinemic patients, an unidentified compound was eluted in a position between beta-aminoisobutyric acid and gamma-aminobutyric acid. This compound was purified to homogeneity from the urine by a combination of extraction with 80% ethanol, repeated column chromatography on Bio-Rad AG-50, and high performance liquid chromatography on a strongly cationic ion exchanger. The compound yielded free histidine on hydrolysis in an evacuated sealed tube with 0.1-6.0 M HCl at 145 degrees C for 5 h, but not at 100 degrees C for 24 h. This compound was determined to be N tau-ribosylhistidine by 1H and 13C NMR spectroscopies. The urinary content of this material in normal and histidinemic children was 17.8 +/- 13.4 (n = 10) and 126 +/- 51 (n = 14) mumol/g creatinine (mean +/- S.D.), respectively, and were closely correlated with those of urinary histidine. The renal clearance value of N tau-ribosylhistidine in humans was 96% of that of creatinine. When rats were fed on diets rich in histidine, the urinary excretion of N tau-ribosylhistidine increased greatly and was well correlated with the intake of histidine.

Amino Acid Metabolism, Inborn Errors↗
PubMed1985

In vitro antigenic reactivity of synthetic lipid A analogues as determined by monoclonal and conventional antibodies.

Cross-reactivities of synthetic lipid A analogues with monoclonal and conventional antibodies against Salmonella lipid A were studied. It was shown that the in vitro antigenicity of a synthetic compound 506, beta-(1----6) D-glucosamine disaccharide 1,4'-bisphosphate, which is acylated at 2'-amino and 3'-hydroxyl groups with (R)-3-dodecanoyloxytetradecanoyl and (R)-3-tetradecanoyloxytetradecanoyl groups, respectively, and has (R)-3-hydroxytetradecanoyl groups at 2-amino and 3-hydroxyl groups, was practically indistinguishable from that of the natural E. coli lipid A preparation, and that both phosphates in positions 1 and 4' as well as ester- and amide-linked fatty acyl residues, particularly 3-acyloxyacyl group, of the glucosamine disaccharide are involved in the cross-reactivity of lipid A as important antigenic determinants.

Animals↗
PubMed1985

tRNA binding to programmed ribosomes increases the ribosomal affinity for tuberactinomycin O.

The binding of 14C-labelled tuberactinomycin O was analysed in equilibrium dialysis cells. The ionic conditions and the concentration of the labelled drug used in the binding assays allowed the binding of just one drug molecule per non-programmed ribosome. Under these conditions, the occupation of the ribosomal P-site by deacylated tRNAPhe in the presence of poly(U) increased the amount of [14C]tuberactinomycin O bound by a factor of two. Kanamycin, gentamicin and neomycin reduced the binding of tuberactinomycin O, whereas chloramphenicol, tetracycline, streptomycin and puromycin had no effect. A stimulation of the binding of tuberactinomycin O was found upon addition of erythromycin.

Anti-Bacterial Agents↗
PubMed1985

Stereochemical studies of a selenium-containing hydrogenase from Methanococcus vannielii: determination of the absolute configuration of C-5 chirally labeled dihydro-8-hydroxy-5-deazaflavin cofactor.

Reduction of 7,8-didemethyl-8-hydroxy-[5-2H]-5-deazariboflavin by the selenium-containing hydrogenase from Methanococcus vannielii gave a C-5 chirally labeled 1,5-dihydro derivative. The absolute configuration of the chiral label was shown to be (R) by comparison of the chemically degraded product with authentic samples of known absolute configurations. Therefore, the steric course of the enzymic reactions involving the 8-hydroxy-5-deazaflavin cofactor can be defined as follows: (a) reduction occurs on the si face of the 5-deazaflavin molecule; (b) oxidation proceeds by the abstraction of the pro-S hydrogen at C-5 of the 1,5-dihydro-5-deazaflavin. Thus, the selenium-containing hydrogenase and 8-hydroxy-5-deazaflavin-dependent NADP+ reductase from M. vannielii are si face specific.

Euryarchaeota↗