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Biomedical subjects

M Minoda

Publications and source records attributed to M Minoda.

At least 19 recordsLinked to original sources
PubMed1999

Apatite formation on ethylene-vinyl alcohol copolymer modified with silanol groups.

The surfaces of ethylene-vinyl alcohol copolymer (EVOH) substrates were modified with silanol (Si-OH) groups, and their apatite forming ability was examined in a simulated body fluid (SBF) with ion concentrations nearly equal to those of human blood plasma or in a solution with ion concentrations 1.5 times those of SBF (1.5SBF). The surface modification of EVOH was carried out by reacting 3-isocyanatopropyltriethoxysilane, followed by hydrolysis of the ethoxysilyl groups into Si-OH groups. However, no apatite formation was observed on the EVOH substrate thus modified, even after 3 weeks in SBF and 1.5SBF. The Si-OH modified EVOH substrate was further modified by hydrolysis and polycondensation of tetraethyoxysilane (TEOS). It was found that the apatite forms on the TEOS-modified substrate within 3 weeks in 1.5SBF. These results suggest that the presence of a large amount of Si-OH groups (i.e., a cluster of Si-OH groups) on the substrate is prerequisite to apatite formation in the body environment. Apatite-EVOH composites prepared by this process might be useful as hard tissues substitutes.

Apatites↗
PubMed1995

Apatite coated on organic polymers by biomimetic process: improvement in its adhesion to substrate by glow-discharge treatment.

A dense, uniform, and highly biologically active bone-like apatite layer can be formed in arbitrary thickness on any kind and shape of solid substrate surface by the following biomimetic method at ordinary temperature and pressure: First, a substrate is set in contact with particles of bioactive CaO-SiO2-based glass soaked in a simulated body fluid (SBF) with inorganic ion concentrations nearly equal to those of human blood plasma so that a number of apatite nuclei are formed on the substrate. Second, the substrate is soaked in another solution with ion concentrations 1.5 times those of SBF (1.5SBF) so that the apatite nuclei grow in situ. In the present study, organic polymer substrates were treated with glow-discharge in O2 gas atmosphere, then subjected to the above-mentioned biomimetic process. The induction periods for the apatite nucleation on all the examined organic polymers were reduced from 24 to 6 h, with glow-discharge treatment. The adhesive strengths of the formed apatite layer to the substrates increased from about 4 to 10 MPa for poly(ethylene terephthalate) and poly-ether sulfone, and from 1 approximately 2 to 6 approximately 7 MPa even for poly(methyl methacrylate), polyamide 6 and polyethylene. It is supposed that highly polar groups such as carbonyl, ester, hydroxyl, and carboxyl ones formed by glow-discharge treatment increased the affinity of a silicate ion with the substrates to decrease the induction period, and also increased the affinity of the apatite with the substrate to increase the adhesive strength.(ABSTRACT TRUNCATED AT 250 WORDS)

Adhesiveness↗
PubMed1994

Apatite coated on organic polymers by biomimetic process: improvement in its adhesion to substrate by NaOH treatment.

A dense, uniform and highly biologically active bone-like apatite layer can be formed in arbitrary thickness on any kind and shape of solid substrate surface by the following biomimetic method at ordinary temperature and pressure. First, a substrate is set in contact with particles of bioactive CaO SiO2 based glass soaked in a simulated body fluid (SBF) with inorganic ion concentrations nearly equal to those of human blood plasma. Second, the substrate is soaked in another solution with ion concentrations 1.5 times those of SBF (1.5 SBF). In the present study, organic polymer substrates treated with 5 M NaOH solution were subjected to the above mentioned biomimetic process. The induction periods for the apatite nucleation on polyethyleneterephthalate (PET), polymethylmethacrylate (PMMA), polyamide 6 (PA6), and polyethersulfone (PESF) substrates were reduced from 24 to 12 h with the NaOH treatment. The adhesive strength of the formed apatite layer were increased from 3.5 to 8.6 MPa, from 1.1 to 3.4 MPa, and from 0.6 to 5.3 MPa with the NaOH treatment, for PET, PMMA, and PA 6, respectively. It was assumed that highly polar groups, such as carboxyl and sulfinyl ones formed by the hydrolysis of an ester group on PET and PMMA and of an amide group on PA 6, or of a sulfonyl group on PESF with the NaOH treatment, attached a large number of hydrated silica dissolved from the glass particles, to accelerate the apatite nucleation, and also to form a strong bond with the apatite. The apatite-organic polymer composites thus obtained are expected to be useful as bone-repairing as well as soft tissue-repairing materials.

Adhesiveness↗
PubMed1993

Abnormal expression of intercellular adhesion molecule-1 on peripheral blood mononuclear cells from patients with systemic lupus erythematosus.

The expression of intercellular adhesion molecule-1 (ICAM-1) on peripheral blood mononuclear cells (PBMC) from patients with systemic lupus erythematosus was observed by flow cytometry. ICAM-1 expression on PBMC was increased in the patients with active disease, and was increased especially on CD5- or CD19+ lymphocytes and monocytes. Furthermore, when B cells were fractionated by Percoll-density gradients, ICAM-1 was more expressed on the low- and the intermediate-density B cells, which are thought to contain activated B cells, than on the high-density B cells, which are thought to contain resting B cells. This might be due to the polyclonal B-cell activation occurring in vivo. Together with the function of B cells and monocytes as antigen presenting cells, this enhanced expression of ICAM-1 on these cells might be associated with the mechanism to maintain the pathophysiology of this disease.

Adolescent↗
PubMed1992

Effects of gamma-interferon and FK506 on resting B cell proliferation of New Zealand black/white F1 mice.

We examined the effects of gamma-interferon (gamma-IFN) and the new immunosuppressant FK506 on resting B cell proliferation of New Zealand black/white F1 hybrid (B/W F1) mice, an animal model of human systemic lupus erythematosus (SLE). gamma-IFN and FK506 inhibited in a dose-dependent manner both B cell proliferation and autoantibody production of resting B cells respectively. There was a synergistic interaction between gamma-IFN and FK506 in their inhibition and they did not exhibit cell cytotoxicity. This in vitro synergism of gamma-IFN and FK506 may have clinical application in that low doses of gamma-IFN and FK506 combinations may be effective to correct polyclonal B cell activation of patients with SLE.

Animals↗
PubMed1992

[Hematologic abnormalities associated with rheumatoid arthritis].

Anemia is frequently found in patients with rheumatoid arthritis (RA) and is the most common extra-articular manifestation RA. The majority of patients with RA have a mild normocytic hypochromic anemia which correlates with the erythrocyte sedimentation rate and with activity of the disease. White blood cell counts are usually in the normal range or only slightly elevated. The differential white blood cell count is usually within normal limits. Eosinophilia and thrombocytosis are often associated with RA. Hematologic abnormalities of RA is correlated to the activity of the disease, and therefore the most important aspect of treatment lies in the general control of the chronic inflammation.

Anemia↗
PubMed1991

Serum level of interferon-gamma in autoimmune diseases.

Interferon-gamma is one of the cytokines which have various immunoregulatory functions. In the present study, the serum interferon-gamma level was determined in autoimmune diseases. It was increased in the active cases of systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD). Since there was a positive correlation between the serum interferon-gamma level and the rate of peripheral mononuclear cells positive for HLA-DR antigen in systemic lupus erythematosus, circulating interferon-gamma might have a biological functions as suggested by many in vitro studies. In rheumatoid arthritis and Sjögren's syndrome, there was no correlation between the serum interferon-gamma level and the clinical findings. These data suggest that interferon-gamma might be associated with the pathogenesis of autoimmune diseases such as SLE and MCTD, and it can be one of the indices for their disease activity.

Antibodies, Anti-Idiotypic↗
PubMed1991

Interferon-gamma inhibition of interleukin 4-induced hyperproliferation of resting B cell from NZB/NZW F1 mice.

To characterize B cell hyperactivity in autoimmune NZB/NZW (B/W) F1 mice, we studied the effects of murine recombinant interferon gamma (IFN-gamma) on interleukin 4 (IL-4) induced resting B cell growth and differentiation. The number of resting B cells of B/W F1 mice were decreased, with more sensitivity to IL-4 than normal mice. Thus, resting B cell hyperresponsiveness to IL-4 was in a dose-dependent manner suppressed by IFN-gamma. This action was most noticeable when IFN-gamma was added to the culture system simultaneously with IL-4. As well, IFN-gamma did not exhibit cytotoxicity. These results suggest that IFN-gamma may have regulatory effects on IL-4 mediated B cell triggering.

Animals↗
PubMed1991

[Relationship between serum interleukin-4 or interferon-gamma level and B cell abnormality in patients with collagen vascular diseases].

The role of interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) in the pathogenesis of the collagen vascular diseases was studied. The serum level of IL-4 was decreased in patients with systemic lupus erythematosus (SLE) and mixed connective tissue disease (MCTD), and was variable in patients with rheumatoid arthritis (RA). The serum level of IFN-gamma was increased in patients with SLE, MCTD and RA. In patients with SLE, there was an inverse correlation between the levels of IL-4 and IFN-gamma. The proliferation and immunoglobulin production of the high-density-B cells in response to IL-4 was suppressed in normal controls, although the degree of suppression was less in patients with SLE. Cell cycle analysis using ethidium bromide demonstrated the similar findings. These data suggest that IL-4 and IFN-gamma might participate in regulating both of growth and differentiation of B cells in vivo. However, immunoglobulin production by whole B cells in response to IL-2 or PHA-induced T-cell factor was extensively facilitated by IFN-gamma in patients with SLE. It is possible that IFN-gamma enhances the differentiation of already-activated B cells, and that polyclonal B cell activation is promoted. Therefore, the failure of the regulatory mechanism by these cytokines might be related to the pathogenesis of these diseases.

B-Lymphocytes↗
PubMed1991

Effect of interferon-gamma on B lymphocytes of patients with systemic lupus erythematosus.

We studied the effect of interferon-gamma (IFN-gamma) on B cells in systemic lupus erythematosus (SLE). Low density B cells, which were fractionated on density gradients of Percoll, increased, and high density B cells decreased in number in SLE. Proliferative response of the high density B cells to interleukin 4 was reduced by IFN-gamma in normal controls, but not in SLE. IgG production of whole B cells induced by interleukin 2 or phytohemagglutinin induced T cell factors was enhanced by IFN-gamma in both normal controls and SLE in which activated B cells were thought to be increased in number. Therefore, IFN-gamma may be one of the factors which promote polyclonal B cell activation in SLE.

B-Lymphocytes↗
PubMed1991

[Effect of anti-idiotypic antibody on production of anti-DNA antibodies by splenocytes in lupus prone mice].

It has been suggested that production of autoantibodies is regulated by idiotype-antiidiotype network. In this study, we examined modulatory effect of the antiidiotypic antibody on the synthesis of anti-DNA antibodies by New Zealand black/New Zealand white F1 mice (B/W F1) splenocytes. The antiidiotypic antibodies were prepared by immunization of a monoclonal anti-DNA antibody derived from B/W F1 to rabbits. The prepared antiidiotypic antibody had specificity to the antigen binding site of anti-DNA antibodies. B/W F1 splenocytes were adjusted to 1 X 10(6) cells/ml and cultured in 1.0 ml aliquots in the presence of varying concentrations of the antiidiotypic antibody for 48 hours. The cells were then washed three times, resuspended in RPMI1640 containing 10% fetal calf serum and cultured again. On days 3 and 7 of the culture, the supernatants were harvested and secretion of anti-DNA antibodies was measured by ELISA. Production of anti-DNA antibodies by B/W F1 splenocytes was suppressed by pretreatment with the antiidiotypic antibody. When the concentration of antiidiotypic antibody was 1 microgram/ml, anti-DNA activity of the supernatants decreased 50%, compared with control on day 3, but the effect was reduced on day 7. The treatment of antiidiotypic antibody did not affect the proliferation and viability of B/W F1 splenocytes. The results indicated that anti-DNA antibodies synthesis were regulated by idiotype-antiidiotype network and could be manipulated by the antiidiotypic antibody.

Animals↗
PubMed1991

[Determining aging changes of melanin granules of human scalp hairs by image analyser].

Using electron micrographs of human hairs, we measured the minor axis and density of hair melanin granules in a 0 year old infant, 20-30 year old adult and 60-70 year old adult by an image analyser for the purpose of determining the aging changes of melanin granules of human scalp hairs. The melanin density of the outer hair cortex was higher than that of the inner hair cortex. There were no differences between the 0 year old infant and the 20-30 year old adult in the minor axis and density of melanin granules, but significant differences were evident in the minor axis between the 60-70 year old adult and the other generations. Significant differences were noted in the density of melanin granules of the inner hair cortex between the 60-70 year old adult and the other generations. As a result of the quantitative analyses, it was proved that the melanin granules of human scalp hair increase in size and decrease in number by age.

Adult↗
PubMed1990

[Image analytic studies of melanin granules of human hairs with transmission electron micrographs].

Using electron micrographs of human hairs, we measured the minor axis and density of melanin granules by an image analyser. The melanin density of the outer hair cortex was higher than that of the inner hair cortex, and significant differences were evident especially in the minor axis and density of melanin granules among individuals. These quantitative analyses as to the minor axis and density of hair melanin granules are a reliable tool for the measurement of hair color.

Adult↗
PubMed1990

Successful treatment for perinephric abscess with recombinant human granulocyte colony-stimulating factor following nephrectomy in a patient of myelodysplastic syndrome: a case report.

The 35-year-old man with myelodysplastic syndrome (MDS) and granulocytopenia with dry cough and high fever was eventually found to have a left perinephric abscess of Staphylococcus aureus. He underwent left nephrectomy and drainage of perinephric space in conjunction with appropriate antibiotics. However, because of persistent granulocytopenia, Staph. aureus never cleared up with formation of only poor granulation. Recombinant human granulocyte colony-stimulating factor (G-CSF) was added to the above treatment leading to prompt improvement in granulocytopenia and emergence of the good granulation tissue. G-CSF will probably become one of the important agents in treating MDS with granulocytopenia.

Abscess↗
PubMed1989

Mixed lymphocyte reaction in interferon-gamma treated (NZB x NZW)F1 mice.

Mouse interferon-gamma was administered to (NZB x NZW)F1 mice, which develop a disease like human systemic lupus erythematosus. Class II antigens on adherent spleen cells and their activity to stimulate allogeneic T lymphocyte in mixed lymphocyte reaction were observed as well as the changes of the clinical findings of the mice. In interferon-gamma treated mice, as compared to control mice, the positive rate for class II antigen on adherent spleen cells was increased, and the mixed lymphocyte reaction using the cells of interferon-gamma treated mice as stimulator cells was enhanced. These findings suggest that the enhancement of antigen presenting activity of adherent spleen cells to T lymphocytes might be associated in the exacerbation of the disease in interferon-gamma treated (NZB x NZW)F1 mice.

Animals↗
PubMed1989

Examination of the inhibitory effects of interferon-gamma on interleukin-4-induced stimulation of resting B cells from NZB/NZW F1 mice.

Percoll fractionation of NZB/NZW F1 mouse B cells revealed an increased ratio of low-density fraction ('activated' B cell fraction) and a decreased ratio of high-density fraction ('resting' B cell fraction), in comparison to normal mouse B cells. Resting B cells of B/W F1 mice were hyperresponsive to interleukin-4 (IL-4), with increased proliferation and IgG anti-DNA antibody production, in comparison to normal mice. The hyper-responses of resting B cells from NZB/NZW F1 mice to IL-4 were affected with dose dependency by interferon-gamma (INF-gamma); specifically, cell proliferation and anti-nuclear antibody production were suppressed in the presence of IFN-gamma. This suppressor action of IFN-gamma was most noticeable when it was added to the culture system simultaneously with IL-4. These findings suggested that the abnormally activated state of NZB/NZW F1 mice B cells can be attenuated by the action of IFN-gamma on resting B cells.

Animals↗