Biomedical subjects

H Yasueda

Publications and source records attributed to H Yasueda.

At least 73 records · Page 4Linked to original sources

PubMed1993

[Immunological and physicochemical properties of Cry j II, the second major allergen of Japanese cedar pollen (Cryptomeria japonica)].

Cry j II, the second major allergen of Japanese cedar (sugi, Cryptomeria japonica) pollen was examined for the allergenicity by intradermal test and RAST. Nineteen of the 25 allergic patients examined, showed positive reaction to the Cry j II. Contents of Cry j II in the extracts of the pollen collected in various regions from 1977 to 1991 showed yearly variation ranging from 2.9 to 14 mg/100 g pollen, whereas the amount of Cry j I in the extract was comparatively stable at about 35 mg/100 g pollen. Physicochemical treatments of Cry j I and Cry j II suggested that specific human IgE antibodies and some mAbs bind to conformational epitopes which are denatured and destroyed by certain treatments.

Allergens↗

PubMed1993

[Changes in antigen-specific IgG, IgG4, and IgE antibodies in patients receiving immunotherapy with house-dust extract].

We measured allergen-specific IgG, IgG4, IgE antibodies and total IgE in sera from 64 patients who were receiving conventional immunotherapy (IT) with house dust (HD) extract. The sera were taken before and after IT. To measure allergen-specific antibodies, we used crude DF antigen, Der f I and Der f II for IgG and IgG4 antibodies, and crude DF antigen for IgE antibodies. The patients were divided into 3 groups: very short term group (IT period < 2 years, n = 9); short term group (2 < = IT period < 7 years, n = 25); long term group (7 years < = IT period, n = 30). The specific IgG antibodies for DF crude antigen did not change in any group. The specific IgG antibodies for Der f I and Der f II increased in the short term group and in the long term group. The specific IgG4 antibodies for all three antigens increased remarkably in the short term group and in the long term group. In the very short term group, however, the specific IgG4 antibodies did not increase for any antigen. Total IgE and the specific IgG antibodies did not change through IT. The specific IgG4 antibodies increased significantly through IT, but the time course of the increment of the IgG4 antibodies was not parallel with the clinical course of IT.

Adult↗

PubMed1993

Confirmation of the airborne occurrence of micron-size airborne pollen antigen carrying particles by immunoblotting.

We confirmed the existence of micron-size airborne particles carrying major pollen antigen of Cryptomeria japonica (Cry j l) and Lolium perenne (Lol p l) by means of an immunoblotting technique and examination by light microscopy. The size of the spots on a nitrocellulose membrane, marking the presence of antigen on the sampler's tape, varied considerably under light microscopic examination. Spots smaller than pollen grains and micron-size spots were observed together with large spots which seem to have been derived from intact pollen grains. The number of micron-size spots counted under a light microscope did not correspond with the number of spots from pollen grain observable with the naked eyes. This suggests other sources of airborne Cry j l particles than intact pollen grains alone.

Air↗

PubMed1993

[Specific IgE antibody titers to hen's egg white lysozyme in allergic children to egg].

Hen's egg white lysozyme (HEL) is one of the minor allergen in hen's egg white. HEL is commonly used to treat disease of respiratory tract, because it have the effect to dissolve mucopolysaccharide and anti-inflammatory action. We examined specific IgE antibody titers (IgE-HEL) in patients with egg allergy and allergic patients to other antigen than egg. Results indicated that 16.37 +/- 29.56 (PRU/ml) (mean +/- SD) of IgE-HEL was found in 30 out of the 39 allergic patients to egg, and 23 (66.7%) out of the 39 patients studied showed RAST scores of more than 2. On the other hand, 1.08 +/- 0.92 (PRU/ml) of IgE-HEL in 12 out of the 44 allergic patients to other antigen than egg, and 5 (11.4%) out of the 44 patients studied showed RAST scores of more than 2. Moreover, we treated a patient who developed anaphylaxis after taking HEL. 1.0 (PRU/ml) of HEL-IgE was found in this patient. These results suggest that we should be careful in treating allergic patients with HEL.

Adolescent↗

PubMed1992

Effect of semi-random mutagenesis at the C-terminal 4 amino acids of human interleukin-6 on its biological activity.

The carboxyl(C)-terminus of human interleukin-6 (hIL-6) has a critical role in the expression of the biological activity of this cytokine. To define the structure-function relationships of this region, semi-random mutagenesis of the C-terminal Leu181-Arg182-Qln183-Met184 sequence of hIL-6 was performed. The mutants were produced in Escherichia coli, renatured, and purified. Alterations of the C-terminal 4 amino acids caused a significant reduction of the proliferative effect of the mutants on MH60.BSF2 and KT-3 cells, and also led to a drastic decrease in receptor binding affinity. These results suggest the importance of a positively charged residue at position 182 or 183 and an alpha-helix at position 181 for the biological activity of hIL-6.

Amino Acid Sequence↗

PubMed1992

Concentration of airborne mite allergens (Der I and Der II) during sleep.

Using a low-noise air sampler and a sensitive radioimmunoassay, we measured the concentration of mite allergens in the air during sleeping with Japanese bedquilts (futon). The airborne allergen levels of Der I (Der p I plus Der f I) and Der II during sleep were 223 and 87.1 pg/m3 of air, respectively. These levels were about 10-fold higher than those during usual domestic life in the living room of the same houses. When the bedquilts were changed to new ones free of mite allergens, the airborne allergen levels of Der I and Der II were decreased to 11.5 and 12.0 pg/m3, respectively. This indicated that the mite airborne allergens during sleep were generated from the used bedding, not from the floor. We believe that exposure to airborne mite allergens during sleep might be an important factor in the development of mite allergies.

Air Pollution, Indoor↗

PubMed1992

[Control of house dust mites and mite allergens by special mite-preventive futon].

We studied the effect of a recently-developed special mite-preventive futon (bedding) on mite population and mite allergen contents (Der I and Der II) in asthmatic children and their families (23 sets) for 2 years. 1. The number of mites (vacuumed samples) in the 124 sets of futon for 2 years was 6.4 (SD +/- 8.8) in average in the mite-preventive futon which was significantly smaller than the number (about 1/10) in the control futon: 70.0 (SD +/- 99) (p less than 0.001). 2. Follow-up studies were made on the mite population about 2 years (3, 6, 9 12 and 27 months afterwards). The numbers of mites in all the mite-preventive futon was always 1/10 or less than that of in the control futon (p less than 0.01). 3. The mite allergens (Der I and Der II) were measured in the cotton stuffing of the futon used for 2 years. The mite allergen counts in the mite-preventive futon averaged about 1/24 of those in the control futon. 4. Airborne mite allergens (Der I and Der II) obtained by beating the futon were measured. The ratio of the mite allergen count in the mite-preventive futon to the control futon was found to be 1:22-264. These results indicate that the special mite-preventive futon always inhibit mite infestation at least 1/10 of that in the ordinary (control) futon and that the count of mite allergens in the cotton stuffing and in the airborne particles was even lower in the mite-preventive futon.

Adult↗

PubMed1991

Identification of a plasmid-coded protein required for initiation of ColE2 DNA replication.

The product of the rep gene of ColE2 is required for initiation of ColE2 DNA replication. The rep gene was placed under the control of the promoters, PL and PR, and the heat-labile cl857 repressor of bacteriophage lambda. The Rep protein was identified as a 35 Kd protein by the maxicell method in combination with heat-induced expression. The protein was efficiently expressed from these promoters in unirradiated cells and accumulated up to a few per cent of the total cellular proteins. It was partially purified (about 80% pure) and its properties examined. The amino acid sequence of the amino terminal portion of the partially purified protein agreed well with that predicted from the nucleotide sequence of the rep gene. One of the characteristic features of the rep gene is frequent usage of rare codons, especially those for arginine. The protein specifically stimulated replication of ColE2 DNA but not that of ColE3 DNA in crude cell extracts of Escherichia coli. Specific binding of the protein to plasmid DNA containing the origin region of ColE2 was demonstrated by the filter binding method. Neither endonuclease activity nor topoisomerase activity was detected by using ColE2 DNA.

Amino Acid Sequence↗

PubMed1991

In-vivo processing of the initiator methionine from recombinant methionyl human interleukin-6 synthesized in Escherichia coli overproducing aminopeptidase-P.

Human interleukin 6 (hIL-6) overproduced in Escherichia coli HB101 was found to partially retain the initiator methionine (Met) residue (Met-hIL-6). In order to remove the residual N-terminal Met in vivo, an attempt was made to express hIL-6 in aminopeptidase-P (Ap-P)-hyperproducing strains, since the N-terminus Met-Pro- structure of nascent recombinant hIL-6 has been shown to be a favoured substrate of the enzyme in vitro. Using a mutant with duplicated Ap-P genes (pepP) on a chromosome or some recombinant strains overproducing Ap-P, we have succeeded in removing the initiator Met from Met-hIL-6 in vivo. The content of the mature product without the initiator Met in the pepP recombinant strains could be increased to approximately 99% from 85%.

Amino Acid Sequence↗

PubMed1991

Enzymatic dispersion of mast cells from human sinus mucosa: characterization of histamine release and its comparison with chopped fragments of the tissue.

Functional characteristics of mast cells in chopped fragments from sinus mucosa, which was dissected from patients with chronic sinusitis, were compared with those from dispersed cells prepared by enzymatic treatment. The results obtained in this study were the following. (1) Both chopped fragments and dispersed cells released histamine in a dose-dependent manner when incubated with anti-IgE. However, higher histamine release was always observed in dispersed cells. (2) Although no differences in the ability to reduce histamine release with salbutamol or forskolin could be observed between chopped fragments and dispersed cells, staurosporin and p-bromophenacyl bromide were more active on dispersed mast cells than chopped fragments. (3) Passive sensitization of dispersed cells with an allergic serum containing IgE to mite could be achieved only after elution of IgE on the cells with lactic acid.

Acetophenones↗

PubMed1991

[The diagnostic value of a new whole blood histamine release test using paper disc-coupled antigens--results compared with intracutaneous test, RAST, and eye test].

We have developed a novel histamine release test (HR) using whole blood and antigen-coupled RAST paper discs, for the screening of allergens rather in a short time with a small amount of blood. Histamine was determined by a RIA kit. In order to evaluate the diagnostic value, the results of the test were compared with those of RAST, intracutaneous tests, and eye tests in 45 allergic patients. HR correlates better with RAST than intracutaneous test in almost all antigens. The closest positive correlation with the other tests was seen in mite allergen, followed by pollen, foods and mould spores in that order. When the HR was positive for house dust, 100% of the patients were also positive for the eye test, which is reported to closely correlate with bronchial provocation tests. HR seemed to be a useful test not only for the screening but also for the determination of pathogenic allergens.

Adolescent↗

PubMed1991

[Kinetics of the falling of airborne mite allergens (Der I and Der II)].

A futon (Japanese quilt) was beaten to disperse mite allergens into the air in a closed room, and the airborne allergens were collected both by Andersen air sampler for particle size analysis and by slit air sampler for kinetic analysis of the clearing of the allergens from the air. After extraction of the allergens from the agar plates in the samplers, two kinds of major mite allergens (Der I and Der II) were immunochemically quantitated. We found that the aerodynamic diameters of both allergens were mainly above 5.5 microns, and that airborne allergen levels decreased to about 10% of the starting level in 30 minutes, indicating the rapidity of the falling of both allergens.

Air Pollutants↗

PubMed1991

[Evaluation of different treatments of Japanese bed quilts for reducing mite allergens].

We evaluated the effectiveness of different treatments of Japanese bedquilt (futon) in reducing mite allergens: vacuum-cleaning, beating plus vacuum-cleaning and washing of the whole futon in water. Before and after these treatments, small amounts of cotton were taken out of the futon and mite allergens were extracted from the cotton into water. The absolute contents of two kinds of major allergens of two Dermatophagoides species were immunochemically quantitated. We found that beating and vacuum-cleaning reduced the allergen contents by only about 40%, whereas washing reduced the allergens by more than 90%. Therefore, for reducing airborne mite allergens generated from futon, we think that washing the whole futon in water is the most effective method.

Allergens↗

PubMed1991

[An enzyme-linked immunosorbent assay (ELISA) for the quantitation of sugi pollen and Dermatophagoides mite allergens and its application for standardization of allergen extracts].

A simple enzyme-linked immunosorbent assay (ELISA) has been developed for the quantitation of the major allergens of sugi pollen, Cry j I and of Dermatophagoides mites, Der I (Der p I/Der f I) and Der II (Der p II/Der f II) for use in the in vitro standardization of allergen extracts. Polystyrene microplates coated with a IgG fraction of rabbit antiserum were incubated first with allergen extracts and then with biotinylated antiserum IgG. The bound allergen-biotinylated antibody complex was detected with commercially available streptavidin-enzyme conjugate followed by the addition of colorimetric substrate. The assay was very sensitive (-0.2 ng/ml) and reproducible (CV% = 1.9-13.8%). The ELISA was compared with the radioimmunoassay previously described, and the results showed a very good correlation between the assays (r = 0.967-0.990). The allergen content in three sugi pollen and three house dust extracts measured by the ELISA also demonstrated a good agreement with the relative potency of these extracts as determined by the intradermal skin test. These results indicate that the ELISA could be useful in the standardization of allergen extracts.

Allergens↗

PubMed1990

Histamine release with a solid-phase-coupled allergen.

Mite allergen was coupled to Sepharose, paper disk or microcrystalline cellulose, and the immobilized allergen was used for histamine release assay in human leukocytes. In terms of the spontaneous release and the reproducibility, the histamine release assay using immobilized allergen was comparable to that using soluble allergen. Histamine release increased progressively with the concentration of the immobilized allergen up to maximal release of histamine which persisted with further increase in immobilized allergen. Histamine release with soluble allergen decreased at higher concentrations of the allergen. The concentration of immobilized allergen required for maximal histamine release was the same as that with soluble allergen, but the maximal release with immobilized allergen was always about 20% lower than that with soluble allergen. Histamine release was not dependent on the density of allergen molecules on Sepharose beads. Although there was a significant correlation between histamine release obtained with a commercial disk, with a disk prepared in our laboratory, and with soluble allergen, the magnitude of the release by both assays using a paper disk was reduced significantly.

Allergens↗

PubMed1990

High-level direct expression of semi-synthetic human interleukin-6 in Escherichia coli and production of N-terminus met-free product.

We have developed a direct expression system for high-level production of recombinant human interleukin-6 (rhIL-6) in Escherichia coli. In this system, (i) the natural N-terminal coding region of the hIL-6 gene was replaced by a synthetic sequence containing A-T rich codons, (ii) dual Shine-Dalgarno (SD) sequences were employed, (iii) an A-T rich segment was inserted in front of the initiation codon to avoid putative mRNA secondary structure in the region and (iv) the natural amber termination codon of the hIL-6 gene was changed to an ocher stop codon. The hIL-6 polypeptide, synthesized at a high level, formed cytoplasmic inclusion bodies. After refolding, the N-terminal methionine was removed by aminopeptidase-P in vitro. The purified recombinant hIL-6 had B-cell differentiation activity equivalent to natural IL-6 from a human T-cell culture.

B-Lymphocytes↗

PubMed1989

Structural and functional organization of ColE2 and ColE3 replicons.

The complete nucleotide sequences of the 1.5 kb regions of ColE2 and ColE3 plasmids containing the segments sufficient for autonomous replication have been determined. They are quite homologous (greater than 90%), indicating that these two plasmids share common mechanisms of initiation of replication and its regulation. An open reading frame with a coding capacity for a protein of about 300 amino acids is present in both ColE2 and ColE3 and it actually specifies the Rep (for replication) protein, which is the plasmid specific trans-acting factor required for autonomous replication. The amino acid sequences of the Rep proteins of ColE2 and ColE3 are quite homologous (greater than 90%). The cis-acting sites (origins) where replication initiates in the presence of the trans-acting factors consist of 32 bp for ColE2 and 33bp for ColE3. They are the smallest of all the prokaryotic replication origins so far reported. They are nonhomologous only at two positions, one of which, a deletion of a single nucleotide in ColE2 (or an insertion in ColE3), determines the plasmid specificity in interaction of the origins with the Rep proteins. Both plasmids carry a region with an identical nucleotide sequence and the one in ColE2, the IncA region, has been shown to express incompatibility against both ColE2 and ColE3. These results indicate that these plasmids share a common IncA determinant. A possibility that a small anti-sense RNA is involved in copy number control and incompatibility (IncA function) was suggested.

Bacteriocin Plasmids↗

PubMed1989

Quantitation of platelet-activating factor by high-performance liquid chromatography with fluorescent detection.

Platelet-activating factors, 1-O-hexadecyl- and 1-O-octadecyl-2-acetyl-sn-glycero-3-phosphocholine (C16-AGEPC and C18AGEPC), were measured by reverse-phase high-performance liquid chromatography with fluorescent detection. C16AGEPC, C18AGEPC, and 1-O-hexadecyl-2-propionyl-sn-glycero-3-phosphocholine, which was suitable for use as an internal standard, were hydrolyzed with phospholipase C, and then the resulting hydrolyzed products were derivatized with 7-methoxycoumarin-3-carbonyl chloride or 7-methoxy-coumarin-4-acetic acid to form 7-methoxycoumarin ester derivatives which permit a fluorometric detection. The lower limit of detection of the derivatives was about 100 pg at a signal-to-noise ratio of 5:1. A commercial platelet-activating factor was demonstrated to contain C16AGEPC (70%) and C18AGEPC (12.8%) by the present method. The present method was also applicable to the measurement of acetyl-CoA:1-alkyl-2-lyso-sn-glycero-3-phosphocholine acetyltransferase activity in a lysate of human polymorphonuclear leukocytes.

Acetyltransferases↗