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Biomedical subjects

S Aiba

Publications and source records attributed to S Aiba.

At least 109 records · Page 6Linked to original sources
PubMed1989

Studies on chitosan: 2. Solution stability and reactivity of partially N-acetylated chitosan derivatives in aqueous media.

The stability of the solutions of partially N-acetylated chitosans was studied by two methods: (1) 1% solutions of the chitosan derivatives in 0.1 M aqueous acetic acid were added dropwise to buffer solutions with pH from 8.6 to 12 and to a 0.1 M NaOH solution; (2) to each 0.5% solution of the derivatives in 0.1 M acetic acid was added the desired amount of a 1 M NaOH solution. The stability data obtained were summarized with respect to the degree of N-acetylation. It was found that the solutions of the derivatives with more than 50% acetyl content were stable even in alkaline conditions and the gelation and precipitation of the solutions did not occur. The reactivity of the derivatives with the degree of N-acetylation of more than 50% was studied using methyl 4-azidobenzoimidate (MABI) and ethylene glycol diglycidyl ether in homogeneous states. It was found that MABI reacted with amino groups of the chitosans only at neutral pH and glycidyl groups reacted at neutral and alkaline pH. It seems that these unique properties of chitosans with a degree of N-acetylation of more than 50% will enable us to prepare new chitosan derivatives.

Acetylation↗
PubMed1989

Multicentric reticulohistiocytosis in a child with sclerosing lesion of the leg. Immunohistopathologic studies and therapeutic trial with systemic cyclosporine.

Multicentric reticulohistiocytosis affecting a 13-year-old boy induced a sclerosing change of the leg. The cellular infiltrate comprising activated T lymphocytes and macrophages and human lymphocyte antigen (HLA)-DR expression by keratinocytes in lesional skin all suggest the involvement of cellular immune reactions. We administered systemic cyclosporine but could not obtain a favorable effect without a concomitant low dosage of prednisone.

Adolescent↗
PubMed1989

Cross-reactivity of murine monoclonal anti-DNA antibodies with human and murine skin: a possible pathogenetic role in skin lesions of lupus erythematosus.

Anti-DNA autoantibodies are known to cross-react with a wide variety of substances including cell-surface molecules. Thus, we examined cross-reactivities of 20 murine monoclonal anti-DNA antibodies with normal human and mouse skin tissues. Hybridomas producing these monoclonal antibodies were established from non-immunized spleen cells from autoimmune MRL-lpr/lpr mice, a strain characterized by spontaneous development of SLE-like disorders including skin changes. They were selected based on their reactivity to DNA in a typical enzyme-linked immunosorbent assay, in which nine monoclonal antibodies were reactive with both double-stranded DNA and single-stranded DNA, whereas nine monoclonals were reactive only with single-stranded DNA. Even though only seven of them were observed to stain nuclei, most of the monoclonal antibodies revealed strong and distinct cross-reactivities to various components of the skin tissues including the epidermal basement membrane, keratinocytes at different locations of the epidermis, melanocytes, Langerhans cells, Thy-1+ dendritic cells in the case of murine skin, and mast cells. Our results suggest a possible role of so-called anti-DNA antibodies with high or low affinities to DNA in the pathogenesis of cutaneous lesions of lupus erythematosus.

Animals↗
PubMed1989

Immunoglobulin-producing cells in plasma cell orificial mucositis.

Plasma cell orificial mucositis is a benign idiopathic condition of orificial mucous membranes characterized histologically by a dense band-like plasmacytic infiltrate. We studied 8 cases of this disease by immunohistochemical methods for subsets of immunoglobulin-producing cells. The infiltrating plasma cells were found to produce mostly IgG and IgA with the predominance of kappa chain-producing cells over lambda chain-producing cells. This polyclonal plasma cell infiltrate composed of IgG- and IgA-producing cells is in accordance with the pattern observed in the inflammatory infiltrate around certain epidermal neoplasms accompanied by the plasmacytic infiltrate, such as actinic keratosis, Bowen's disease, squamous cell carcinoma, and syringocystadenoma papilliferum.

Adult↗
PubMed1989

In vitro induction of proliferation and differentiation of uncommitted spleen cells by epidermal cell-derived cytokines.

In this study of the hematopoietic functions of the cytokines released by the epidermal cells, we examined the effects of culture supernatants of epidermal cells and dermal cells from new born mice on uncommitted spleen cells. The epidermal cell culture supernatants (ECCS) stimulated the proliferation of nylon wool-passed I-A-spleen mononuclear cells (SC) much more vigorously than did the dermal cell culture supernatants (DCCS). The main responding cells were I-A-Thy-1-Lyt-1-Lyt-2-cells. Giemsa staining of cytocentrifuge preparations disclosed that SC cultured with ECCS or DCCS were composed of about 50% lymphoid cells, 30-40% granulocytes, 10% macrophages, and a few mast cells and megakaryocytes. Immunoperoxidase staining of the cytocentrifuge preparations showed that SC cultured with ECCS consisted of less than 10% I-A-, about 40% Thy-1+, 10-20% Lyt-1+, less than 6% Lyt-2+, 30-40% Mac-1+, 10-30% Mac-2+, 40-55% Mac-3+, and 10-20% Asialo-GM1+ cells. A double immunofluorescence study showed that 11% of Mac-1+ cells, 34% of Mac-2+ cells and 14% of Mac-3+ cells were I-A+, whereas all the I-A+ cells were either Mac-1+, Mac-2+, or Mac-3+, and that the percentage of Thy-1+ Asialo-GM1+ was less than 5%. In a panel of 3 available purified cytokines known to be secreted by keratinocytes which were used as a positive control, a similar stimulatory effect was recognized with GM-CSF and IL-3 but no such effect was found with recombinant IL-1. These data suggest that ECCS can stimulate the development of uncommitted SC into lymphocytes, different subsets of macrophages probably including Langerhans cells, granulocytes, mast cells and megakaryocytes. They constitute direct and convincing evidence indicating the combined effect of various cytokines released by epidermal cells on the proliferation and maturation of hematopoietic precursor cells into different immunocompetent cells in the skin.

Animals↗
PubMed1989

[A fatal case of pemphigus vulgaris with interstitial pneumonia occurring during gold therapy].

We report a case of a 52-year-old female with therapy-resistant pemphigus vulgaris. She was treated with prednisone, azathioprine and gold sodium thiomalate. After administration of a total dose of 110 mg gold sodium thiomalate, she suddenly developed pityriasis rose-like drug eruptions and interstitial pneumonia and died despite intensive care including pulse therapy. In Japan, there have been 8 reported cases of pemphigus or bullous pemphigoid that developed interstitial pneumonia during gold therapy. In these 7 cases, interstitial pneumonia occurred after administration of 110 to 430 mg gold sodium thiomalate, and 4 cases died. This rate of death is higher than those with other diseases: i.e., 9 dead cases among 99 cases of interstitial pneumonia developing in patients with rheumatoid arthritis or asthma under treatment with gold sodium thiomalate. We think that it is necessary to reevaluate the combined treatment of sodium thiomalate and other immunosuppressive drugs such as azathioprine in pemphigus, because we also found 2 other fatal cases among the 4 reported ones with interstitial pneumonia.

Azathioprine↗
PubMed1989

Epidermodysplasia verruciformis accompanied by large granular lymphocytosis. Report of a case and immunological studies.

A 34-year-old man with epidermodysplasia verruciformis showed increased natural killer (NK) cell activity in his peripheral blood cells, which was found to be due to abnormal expansion of large granular lymphocytes (LGL). Surface marker analysis of LGL in a two-color immunofluorescence test demonstrated that all LGL subsets, Leu-7+11-, Leu-7+11+, and Leu-7-11+, were increased. In contrast, his peripheral blood mononuclear cells showed a remarkable decrease in response to T cell mitogens, which could not be restored by depletion of the LGL subpopulation from the mononuclear cells. Immunohistologic studies for dermal distribution of LGL showed numerous Leu-7+ cells but no Leu-11+ cells at the sites of delayed hypersensitivity reaction or interferon beta- or interferon gamma-injected sites. These findings suggest that the elevated NK cell activity in this patient with epidermodysplasia verruciformis was caused by overall expansion of normal LGL subpopulations, but that the decreased T-cell mitogenic response represented a primary T-cell defect rather than a direct suppression by increased NK cells. It is noteworthy that despite this extraordinary increase of all LGL subpopulations in the blood, Leu-11+ NK cells never appeared in the skin.

Adult↗
PubMed1988

Role of tyrosine-80 in the stability of kanamycin nucleotidyltransferase analyzed by site-directed mutagenesis.

A thermostable mutant of kanamycin nucleotidyltransferase (KNTase) with a single amino acid replacement of Asp at position 80 by Tyr has been isolated by a novel screening method in a previous study [Matsumura, M. & Aiba, S. (1985) J. Biol. Chem. 260, 15298-15303]. To elucidate the role of Tyr80 in stabilizing the enzyme, the KNTase gene was modified by site-directed mutagenesis so that the codon for Asp80 of the wild type was replaced by that for Ser, Thr, Ala, Val, Leu, Phe and Trp, respectively. The eight mutant KNTases including Tyr80 were all purified, as well as the wild-type enzyme. The heat-inactivation rate constants were determined at 58 degrees C and the half-life values were found to be correlated with the hydrophobicity of the amino acid residues replaced at the unique position. The Gibbs energy change of unfolding in water of KNTase assessed from urea denaturation (25 degrees C, pH 7.0) was also found to be correlated with hydrophobicity. The results suggest that different amino acids at position 80 of KNTase contribute to the stability of the protein by hydrophobic interactions. In the case of tyrosine at position 80 the unusually high stability of the enzyme compared to the Phe80 enzyme suggests that the hydroxyl group also contributes to the conformational stability.

Binding Sites↗
PubMed1988

Acquired progressive lymphangioma as a flat erythematous patch on the abdominal wall of a child.

An erythematous patch was noted on the abdominal wall of an 8-year-old boy. The lesion showed a prolonged initial clinical course, followed by rapid later growth, finally reaching 3.7 X 7.0 cm in size over four years. Despite the harmless clinical appearance, the lesion was histologically characterized by tortuous vascular channels with some cellular atypia. Immunoperoxidase staining disclosed no factor VIII-related antigen or reaction to Ulex europaeus I lectin on tumor cells. There has been no recurrence three years after local excision. Although many features in our case resemble those reported in the literature under the term low-grade angiosarcoma, our preferred designation for such cases is acquired progressive lymphangioma, rather than angiosarcoma, because of their benign behavior.

Abdominal Muscles↗
PubMed1988

Immunohistologic studies in Schamberg's disease. Evidence for cellular immune reaction in lesional skin.

We studied eight cases of Schamberg's disease immunohistologically by using monoclonal antibodies. The dermal infiltrate was composed of Leu-1-reactive T cells, OKT6-reactive Langerhans' cells, and Leu-M5-reactive (Leu-M5+) macrophages. Among them, the major population consisted of T cells with the predominance of Leu-3a-reactive (Leu-3a+) T cells over Leu-2a-reactive (Leu-2a+) T cells. On the other hand, the epidermotropic mononuclear cells consisted of Leu-2a+ and Leu-3a+ T cells without any predominant pattern, and Leu-M5+ macrophages. Furthermore, note that a pemphiguslike intercellular staining pattern was observed in the epidermis in most of the cases, when the sections were stained either with anti-HLA-DR antibody or with OKT6, suggesting the HLA-DR antigen expression on the keratinocyte surface and possibly an enlargement of Langerhans' cells. Based on these immunohistologic findings, we think that Langerhans' cells play an important role in the pathomechanism of Schamberg's disease, and that cellular immune reactions are taking place in the lesional skin.

Adult↗
PubMed1987

Possible functional impairment of Langerhans' cells in vitiliginous skin. Reduced ability to elicit dinitrochlorobenzene contact sensitivity reaction and decreased stimulatory effect in the allogeneic mixed skin cell lymphocyte culture reaction.

We used patch testing to compare the ability to elicit contact sensitivity to dinitrochlorobenzene (DNCB) of uninvolved with vitiliginous skin of 31 patients with vitiligo. The induction of DNCB contact sensitivity was possible in the vitiliginous skin in the same way as in normal skin. The DNCB contact sensitivity reactions, however, were generally diminished in vitiliginous skin, although the number of cases showing similar DNCB contact reactivity between normal and vitiliginous skin increased when the sensitization procedure was performed in vitiliginous skin instead of normal skin. On the other hand, delayed skin reactions to intradermally injected Candida albicans antigen were not suppressed in vitiliginous skin. The number of Langerhans' cells was not decreased in vitiliginous skin as compared with that of normal skin. The epidermal cells derived from vitiliginous skin, however, tended to show a lower stimulatory effect in the allogeneic mixed skin cell lymphocyte culture reaction than those from normal skin. These results suggest a possibility of functional impairment of Langerhans' cells in vitiliginous skin.

Antigens, Fungal↗
PubMed1987

Covalent immobilization of chitosan derivatives onto polymeric film surfaces with the use of a photosensitive hetero-bifunctional crosslinking reagent.

Partially N-acetylated chitosan was covalently immobilized onto polymeric film surfaces using the photosensitive hetero-bifunctional crosslinking reagent, methyl 4-azidobenzoimidate, which was previously attached to the chitosan by the reaction between an imidoester group of the reagent and a free amino group of the chitosan. The grafting was accomplished by irradiating with ultraviolet light the modified chitosan being coated on the film surfaces to photolysis arylazide groups, thus crosslinking the chitosan and the underlying substrate polymer together. For ultraviolet absorption and infrared spectroscopy, the irradiation time of 3 min was found to be sufficient for the photolysis of the azide group. The thickness of the immobilized chitosan layer was estimated to be of the order of 30-150 nm using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The chitosan molecules immobilized on the surfaces could be chemically modified by several reagents and also treated with a heparin solution to form a polyelectrolyte complex on the surface. The ionically bound heparin was partially released into a phosphate buffer solution.

Acetylation↗
PubMed1987

Functional analysis of Ia antigen-bearing keratinocytes: mixed skin lymphocyte culture between Ia antigen-bearing Pam 212 cells and allogeneic and syngeneic splenic T cells.

Keratinocytes express Ia antigens in various skin disorders, although the biological role of these Ia antigen-bearing (Ia+) keratinocytes remains unclear. We induced Ia antigens on Pam 212 murine keratinocyte cell line by interferon-gamma(IFN-gamma) and using these cells, we performed the mixed skin lymphocyte culture with syngeneic BALB/c or allogeneic C3H/He splenic T cells. Unexpectedly, Pam 212 cells were found to stimulate both syngeneic and allogeneic T cells irrespective of IFN-gamma treatment. However, both syngeneic and allogeneic T cells cultured with IFN-gamma-treated Pam 212 cells incorporated [3H]thymidine much more actively than those cultured with IFN-gamma-untreated Pam 212 cells. This stimulation was not inhibited by monoclonal anti-I-Ad antibody. Analysis of the responding T cells demonstrated that the syngeneic T-cell stimulation by IFN-gamma-treated Pam 212 cells occurred in both purified Lyt 1-T cells and Lyt 2- T cells. Furthermore, we found that the T cells cultured with the IFN-gamma-treated cells were composed of two morphologically different types of cells. Determination of their surface phenotype showed that the small cell population consisted of 57% Thy-1+, 23% Lyt-1+, 6% Lyt-2+, and 9% asialo-GM1+ cells, while the large cells consisted of 53% Thy-1+, 15% Lyt-1+, 9% Lyt-2+, and 24% asialo-GM1+ cells. These findings suggest that IFN-gamma-treated Pam 212 cells could stimulate more than one kind of splenic T cell populations.

Animals↗
PubMed1987

HLA-DR antigen expression on keratinocytes in highly inflamed parts of psoriatic lesions.

We have investigated the immunoperoxidase staining pattern in the epidermis and dermal infiltrates of highly inflamed portions of psoriatic lesions, selecting for biopsy early pinpoint lesions or margins of active plaque lesions. We found positive intercellular staining for HLA-DR antigens in localized areas of the epidermis in about half of the patients tested. In contrast, OKT6 antigen was found only on the dendritic cells in the epidermis and dermis in all cases. These findings support the hypothesis that an active cellular immune reaction involving the epidermis, possibly associated with the expression of HLA-DR antigens on keratinocytes, occurs in the highly inflamed areas of psoriatic lesions, particularly in early pinpoint lesions or at the edges of spreading plaque lesions.

Dermatitis↗
PubMed1987

Cloning and nucleotide sequence of the penicillinase antirepressor gene penJ of Bacillus licheniformis.

The penicillinase antirepressor gene, penJ, of Bacillus licheniformis ATCC 9945a was cloned in Escherichia coli by using pMB9 as a vector plasmid. The penicillinase gene, penP, its repressor gene, penI, and penJ were encoded on the cloned 5.2-kilobase HindIII fragment of the recombinant plasmid pTTE71. The penJ open reading frame was composed of 1,803 bases and 601 amino acid residues (molecular weight, 68,388). A Shine-Dalgarno sequence was found 7 bases upstream from the translation start site. Since this sequence was located in the 3'-terminal region of the penI gene, penJ might be transcribed together with penI as a polycistronic mRNA from the penI promoter. Frameshift mutations of penJ were constructed in vitro from pTTE71, and the penJ mutant gene was introduced into B. licheniformis by chromosomal recombination. The transformant B. licheniformis U173 (penP+ penI+ penJ) turned out to be uninducible for penicillinase production, whereas the wild-type strain (penP+ penI+ penJ+) was inducible. Only when these three genes (penP, penI, and PenJ) were simultaneously subcloned in Bacillus subtilis did the plasmid carrier exhibit inducible penicillinase production, as did wild-type B. licheniformis. It was concluded that penJ is involved in the penicillinase induction. The regulation of penP expression by penI and penJ is discussed.

Bacillus↗