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Biomedical subjects

Yoshiki Miyachi

Publications and source records attributed to Yoshiki Miyachi.

At least 19 recordsLinked to original sources
PubMed2006

IgE-activated mast cells in combination with pro-inflammatory factors induce Th2-promoting dendritic cells.

Dendritic cells (DCs) and mast cells (MCs) co-localize in peripheral tissues of antigen entry, i.e. skin and mucosa. Due to the proximity of these two cell types, activation of MCs may affect DC functions. Here, we co-cultured human monocyte-derived DCs with cord blood-derived MCs activated by cross-linking of FcepsilonRI to elucidate the net effect of the whole MC products on DCs. Activated MCs induced maturation of DCs, and potently suppressed IL-12p70 production by the DCs. Whereas co-culture of DCs with activated MCs alone did not significantly influence the type of CD4(+) T cell responses induced by the DCs, DCs co-cultured with activated MCs in the presence of pro-inflammatory or T(h)1-inducing factors caused T(h)2 polarization. Although histamine was involved in the induction of DC maturation and T(h)2 polarization by activated MCs, a combinatorial effect of various MC-derived factors, including those acting in a cell contact-dependent manner, was required for the optimal induction of T(h)2-promoting DCs. Furthermore, we demonstrated that clusters of DCs are located closely with MCs in lesions of atopic dermatitis. Collectively, this study suggests that the interaction between DCs and IgE-activated MCs in a pro-inflammatory or even T(h)1-prone environment is instrumental in maintaining and augmenting T(h)2 responses in allergy, and that disruption of the DC-MC interaction may constitute an effective strategy to treat ongoing allergic diseases.

Cell Differentiation↗
PubMed2006

Japanese version of the Dermatology Life Quality Index: validity and reliability in patients with acne.

BACKGROUND: Patient-reported quality of life is strongly affected by some dermatologic conditions. We developed a Japanese version of the Dermatology Life Quality Index (DLQI-J) and used psychometric methods to examine its validity and reliability. METHODS: The Japanese version of the DLQI was created from the original (English) version, using a standard method. The DLQI-J was then completed by 197 people, to examine its validity and reliability. Some participants completed the DLQI-J a second time, 3 days later, to examine the reproducibility of their responses. In addition to the DLQI-J, the participants completed parts of the SF-36 and gave data on their demographic and clinical characteristics. Their physicians provided information on the location and clinical severity of the skin disease. RESULTS: The participants reported no difficulties in answering the DLQI-J items. Their mean age was 24.8 years, 77.2% were female, and 78.7% had acne vulgaris. The mean score of DLQI was 3.99(SD: 3.99). The responses were found to be reproducible and stable. Results of principal-component and factor analysis suggested that this scale measured one construct. The correlations of DLQI-J scores with sex or age were very poor, but those with SF-36 scores and with clinical severity were high. CONCLUSION: The DLQI-J provides valid and reliable data despite having only a small number of items.

Acne Vulgaris↗
PubMed2006

Bradykinin is a potent pruritogen in atopic dermatitis: a switch from pain to itch.

Histamine, substance P, serotonin and bradykinin were applied by iontophoresis to lesional and visually non-lesional skin of 14 patients with atopic dermatitis, and normal skin of 15 healthy volunteers. Itch could be evoked by light stroking of skin with a cotton swab (alloknesis) in all lesional skin sites, but not in non-lesional or normal skin. Substances were applied in the same skin area before and 3 h after administration of placebo or antihistamine (olopatadine hydrochloride: H1-receptor-blocker). Intensities of itch and pain sensation and areas of flare and wheal were measured. All the substances induced significantly more intense itch in lesional skin than in non-lesional skin of patients. Even bradykinin, which evoked only weak itch and pain of similar intensities in non-lesional skin of patients and in healthy volunteers, induced intense itch in lesional skin, while the simultaneously increased pain did not suppress the itch sensation, indicating central sensitization. Histamine- and substance P-induced itch was almost completely suppressed by antihistamines, whereas bradykinin- and serotonin-induced itch was not. This suggests that substance P is a histamine-dependent pruritogen also in lesional skin under sensitized conditions but that bradykinin and serotonin are histamine-independent pruritogens in lesional skin. It is concluded that serotonin and bradykinin, classic endogenous algogens, can turn into potent histamine-independent pruritogens in lesional skin of atopic dermatitis.

Adult↗
PubMed2006

Mouse homologue of skin-specific retroviral-like aspartic protease involved in wrinkle formation.

Retroviral proteases are encoded in the retroviral genome and are responsible for maturation and assembly of infectious virus particles. A number of retroviral protease sequences with retroviral elements are integrated in every eukaryotic genome as endogenous retroviruses. Recently, retroviral-like aspartic proteases that were not embedded within endogenous retroviral elements were identified throughout the eukaryotic and prokaryotic genomes. However, the physiological role of this novel protease family, especially in mammals, is not known. During the high throughput in situ hybridization screening of mouse epidermis, as a granular layer-expressing clone, we identified a mouse homologue of SASPase (Skin ASpartic Protease), a recently identified retroviral-like aspartic protease. We detected and purified the endogenous 32-kDa (mSASP32) and 15-kDa (mSASP15) forms of mSASP from mouse stratum corneum extracts and determined their amino acid sequences. Next, we bacterially produced recombinant mSASP15 via autoprocessing of GST-mSASP32. Purified recombinant mSASP15 cleaved a quenched fluorogenic peptide substrate, designed from the autoprocessing site for mSASP32 maximally at pH 5.77, which is close to the pH of the epidermal surface. Finally, we generated mSASP-deficient mice that at 5 weeks of age showed fine wrinkles that ran parallel on the lateral trunk without apparent epidermal differentiation defects. These results indicate that the retroviral-like aspartic protease, SASPase, is involved in prevention of fine wrinkle formation via activation in a weakly acidic stratum corneum environment. This study provides the first evidence that retroviral-like aspartic protease is functionally important in mammalian tissue organization.

Amino Acid Sequence↗
PubMed2006

Control of autoimmune myocarditis and multiorgan inflammation by glucocorticoid-induced TNF receptor family-related protein(high), Foxp3-expressing CD25+ and CD25- regulatory T cells.

Anomalies of naturally occurring CD4+ regulatory T cells (Treg) cause severe autoimmune/inflammatory diseases in humans and rodents. The transcription factor Foxp3 is currently the most specific marker for natural CD4+ Treg, but it would be useful if other Treg markers, particularly cell surface molecules, could be elucidated. We demonstrate in this study that the vast majority of Foxp3-expressing CD4+ T cells (whether CD25+ or CD25-) show constitutive high-level expression of glucocorticoid-induced TNFR family-related gene/protein (GITR). Transfer of T cell or thymocyte suspensions depleted of GITR(high) cells produces in BALB/c nude mice a wider spectrum and more severe forms of autoimmune diseases than does transfer of similar cell suspensions depleted of CD25+ CD4+ T cells only. Notably, mice that receive cells depleted of GITR(high) populations develop severe multiorgan inflammation that includes fatal autoimmune myocarditis resembling giant cell myocarditis in humans, accompanying high-titer anti-myosin autoantibodies. Similar transfer of GITR(high)-depleted cells from prediabetic NOD mice to NOD-SCID mice accelerates the development of diabetes and induces skeletal muscle myositis and other autoimmune/inflammatory diseases. We conclude that GITR(high), Foxp3-expressing natural Treg, containing both CD25+ and CD25- cell populations, contribute to preventing a variety of autoimmune/inflammatory diseases, and depletion of these cells allows the activation of even weak or rare autoreactive T cells yielding widespread severe autoimmune disease. Diseases induced in this way include many which have been suspected of an autoimmune etiology in humans without much evidence. GITR(high), Foxp3-expressing natural Treg represent a potential target for the treatment and prevention of these diseases.

Adoptive Transfer↗
PubMed2006

4-Nitroquinoline 1-oxide forms 8-hydroxydeoxyguanosine in human fibroblasts through reactive oxygen species.

4-Nitroquinoline 1-oxide (4NQO) is thought to elicit its carcinogenicity by producing DNA adducts after being metabolized to 4-hydroxyaminoquinoline 1-oxide, which forms 8-hydroxydeoxyguanosine (8OHdG), oxidative damage. To determine whether reactive oxygen species (ROS) are involved in the generation of 8OHdG by 4NQO, we used high-performance liquid chromatography and immunohistochemistry to measure the levels of 8OHdG in normal human fibroblasts treated with 4NQO. The extent of ROS induced by 4NQO was determined by using fluorescent probes to detect ROS, electron paramagnetic resonance spectrometry using a cell-free system, and measurement of intracellular glutathione (GSH) levels. In fibroblasts, 4NQO dose dependently increased 8OHdG levels. Hydrogen peroxide (H2O2) and superoxide were detected in cells treated with 4NQO by using dichlorofluorescin diacetate and hydroethidine, respectively. The addition of catalase to culture medium reduced 8OHdG levels and the intensity of dichlorofluorescin fluorescence, while 4NQO generated hydroxyl radicals in the cell-free system. These findings suggest that 4NQO treatment leads to formation of superoxide, H2O2, and hydroxyl radicals, resulting in the production of a substantial amount of 8OHdG in DNA. Neither the level of 8OHdG nor that of GSH had returned to the basal level 24 h after removal of 4NQO even at a concentration as low as 1 microM. Our results suggest that generation of ROS and depletion of GSH in cells are also important factors for the generation of 8OHdG by 4NQO. This paper describes practical and sensitive ways to detect ROS and 8OHdG and discusses a new functional pathway to elicit genotoxicity.

4-Nitroquinoline-1-oxide↗
PubMed2006

Prostacyclin-IP signaling and prostaglandin E2-EP2/EP4 signaling both mediate joint inflammation in mouse collagen-induced arthritis.

Prostaglandin (PG)I2 (prostacyclin [PGI]) and PGE2 are abundantly present in the synovial fluid of rheumatoid arthritis (RA) patients. Although the role of PGE2 in RA has been well studied, how much PGI2 contributes to RA is little known. To examine this issue, we backcrossed mice lacking the PGI receptor (IP) to the DBA/1J strain and subjected them to collagen-induced arthritis (CIA). IP-deficient (IP-/-) mice exhibited significant reduction in arthritic scores compared with wild-type (WT) mice, despite anti-collagen antibody production and complement activation similar to WT mice. IP-/- mice also showed significant reduction in contents of proinflammatory cytokines, such as interleukin (IL)-6 in arthritic paws. Consistently, the addition of an IP agonist to cultured synovial fibroblasts significantly enhanced IL-6 production and induced expression of other arthritis-related genes. On the other hand, loss or inhibition of each PGE receptor subtype alone did not affect elicitation of inflammation in CIA. However, a partial but significant suppression of CIA was achieved by the combined inhibition of EP2 and EP4. Our results show significant roles of both PGI2-IP and PGE2-EP2/EP4 signaling in the development of CIA, and suggest that inhibition of PGE2 synthesis alone may not be sufficient for suppression of RA symptoms.

Animals↗
PubMed2005

Tight junctions in Schwann cells of peripheral myelinated axons: a lesson from claudin-19-deficient mice.

Tight junction (TJ)-like structures have been reported in Schwann cells, but their molecular composition and physiological function remain elusive. We found that claudin-19, a novel member of the claudin family (TJ adhesion molecules in epithelia), constituted these structures. Claudin-19-deficient mice were generated, and they exhibited behavioral abnormalities that could be attributed to peripheral nervous system deficits. Electrophysiological analyses showed that the claudin-19 deficiency affected the nerve conduction of peripheral myelinated fibers. Interestingly, the overall morphology of Schwann cells lacking claudin-19 expression appeared to be normal not only in the internodal region but also at the node of Ranvier, except that TJs completely disappeared, at least from the outer/inner mesaxons. These findings have indicated that, similar to epithelial cells, Schwann cells also bear claudin-based TJs, and they have also suggested that these TJs are not involved in the polarized morphogenesis but are involved in the electrophysiological "sealing" function of Schwann cells.

Animals↗
PubMed2005

A novel method to control the balance of skin microflora Part 2. A study to assess the effect of a cream containing farnesol and xylitol on atopic dry skin.

BACKGROUND: It is recognized that colonization by Staphylococcus aureus (SA) on the skin is one of the factors that can worsen atopic dermatitis (AD). Antibiotics and germicides are not the best choice to remove bacteria from the skin of AD patients, because of problems of irritation to the skin and bacterial resistance. We therefore turned our attention to the biofilm of SA with the aim of removing only SA from the skin surface of AD patients. We found that xylitol (X) and farnesol (F) synergistically inhibited biofilm formation by SA and dissolved biofilm formed in vivo (Part 1). OBJECTIVE: To test whether application of AD for 1 week with FX cream can reduce SA without affecting Staphylococcus epidermidis. METHODS: A randomized, double-blind, placebo-controlled right-and-left comparison study was performed. The arms of 17 patients with dry-type AD were applied with skin-care cream including/or not including a 0.02% F and 5% X combination for 1 week. The clinical response, biophysical assessment of the skin surface and counts of skin microflora were recorded before and after 1 week of therapy. RESULTS: The ratio of SA in total bacteria at sites to which FX cream had been applied was significantly decreased after 1 week (P = 0.007), compared with before application and with placebo sites (P = 0.045). The mean skin conductance (a parameter indicating the state of hydration of the skin surface) of FX cream sites was increased significantly compared with the conductance before application (P = 0.0001) and at placebo sites (P = 0.002). CONCLUSION: This study provides evidence supporting the idea that cream containing F and X is a useful skin-care agent for atopic dry skin colonized by SA.

Administration, Cutaneous↗
PubMed2005

Somatic mosaicism of CIAS1 in a patient with chronic infantile neurologic, cutaneous, articular syndrome.

Chronic infantile neurologic, cutaneous, articular syndrome (CINCA syndrome) is a severe inflammatory disease that was recently found to be associated with mutations in CIAS1. However, CIAS1 mutations have been detected in only half of CINCA syndrome patients, and it remains unclear which genes are responsible for the syndrome in the remaining patients. We describe here a patient with CINCA syndrome who exhibited CIAS1 somatic mosaicism. We genetically analyzed the CIAS1 gene in various blood cells and the buccal mucosa of the patient. The production of interleukin-1beta (IL-1beta) by peripheral blood mononuclear cells (PBMCs) was measured by enzyme-linked immunosorbent assay, and the ability of the mutant CIAS1 gene to enhance ASC-dependent NF-kappaB activation was assessed to confirm that the mutations of CIAS1 found were responsible for the patient's clinical manifestations of the CINCA syndrome. The patient had 1 heterologous single-nucleotide polymorphism, 587G>A (S196N), and 1 heterologous mutation, 1709A>G (Y570C), in exon 3 of CIAS1. The latter mutation was found to occur as somatic mosaicism. The patient's PBMCs produced a large amount of IL-1beta in the absence of stimulation, unlike those from controls or from his mother, who also bore the S196N polymorphism. In addition, the Y570C mutation (with or without the S196N polymorphism) increased the ability of CIAS1 to induce ASC-dependent NF-kappaB activation, unlike the wild-type gene or the gene bearing the S196N polymorphism alone. The findings in this patient indicate that somatic mosaicism is one reason CIAS1 mutations have not been detected in some patients with CINCA syndrome.

Adolescent↗
PubMed2005

Electrically evoked itch in humans.

We compared itch sensations and axon reflex flare induced by transcutaneous electrical (0.08-8 ms, 2-200 Hz) and chemical (histamine iontophoresis; 100 microC) stimulation. Stimuli were applied to non-lesional volar wrist skin in 20 healthy human subjects and 10 patients with atopic dermatitis. Intensity of evoked itch and pain sensations were rated on a numerical rating scale (NRS) of 0 (no sensation) to 10 (the maximum sensation imaginable). The axon reflex erythema was measured by laser Doppler imager and areas of alloknesis (itch evoked by light brushing) and hyperknesis (itch evoked by pricking) were assessed psychophysically. Electrical stimulation was most effective for stimulus durations >or=2 ms and frequencies >or=50 Hz. It evoked pure itch as threshold sensation in 80% of the subjects that was perceived with a delay of approximately 1 s. Itch intensities of up to 7/10 were not accompanied by an axon reflex flare. In contrast, histamine provoked a massive increase of axon reflex erythema and maximum itch ratings of 3.1+/-0.2. The extention of alloknesis areas (2.3+/-0.5 cm) evoked by electrical stimulation clearly exceeded those induced by histamine (0.7+/-0.3 cm). Healthy subjects and patients with atopic dermatitis did not differ significantly in their response to either stimulation. We conclude that C-fiber activation underlies the electrically evoked itch sensation. The low electrical thresholds and the absence of an axon reflex flare suggest that these fibers are not identical with the previously described mechano-insensitive histamine responsive C fibers, but represent a separate peripheral neuronal system for the induction of itch.

Adult↗
PubMed2005

T-cadherin negatively regulates the proliferation of cutaneous squamous carcinoma cells.

T-cadherin is a unique member of the cadherin superfamily that lacks the transmembrane and cytoplasmic domains, and is instead linked to the cell membrane via a glycosyl-phosphatidylinositol anchor. We previously reported that T-cadherin was specifically expressed on the basal keratinocytes of the epidermis, and the expression of T-cadherin was significantly reduced in invasive cutaneous squamous cell carcinoma (SCC) and in the lesional skin of psoriasis vulgaris. In this study, to obtain an insight into the role of T-cadherin in keratinocytes, we used transfection methods and examined the effect of overexpression or knockdown of T-cadherin in immortalized keratinocyte cell lines derived from SCC. T-cadherin overexpressed cells showed clearly reduced cell proliferation, but the influence of cell-cell adhesiveness and cell mobility was not detected. Using a tetracycline-regulated expression system, we also confirmed that the suppression of cell proliferation was dependent on the expression level of T-cadherin. Cell cycle analysis demonstrated that over expression of T-cadherin induced a delay in the G(2)/M phase. Our findings suggest that T-cadherin acts as an endogenous negative regulator of keratinocyte proliferation and its inactivation is the cause for keratinocyte hyperproliferation in SCC or in psoriasis vulgaris.

Cadherins↗
PubMed2005

A novel XPA gene mutation and its functional analysis in a Japanese patient with xeroderma pigmentosum group A.

Most Japanese patients with xeroderma pigmentosum group A (XPA) have the homozygous intron 3 splicing mutations (AlwNI mutation). Here, we report a Japanese XPA patient, XP79KO, a compound heterozygote with a newly identified T to G transversion at splice donor site in intron 1 in one allele, and with the AlwNI mutation in another allele in the XPA gene. The mutation in intron 1 creates two new abnormal splice sites that resulted in two types of aberrant mRNA. These abnormal splicings cause frameshifts that make stop codons downstream. No XPA protein was detected in XP79KO fibroblasts.

Child↗
PubMed2005

Elastin gene expression in blepharochalasis.

Blepharochalasis is a rare condition characterized by recurrent episodes of eyelid edema lead to an atrophic eyelid skin with fine wrinkles and peculiar bronze discoloration. A 32-year-old female presented with loose and redundant skin of the bilateral eyelids. We diagnosed her disease as blepharochalasis by clinical features and by disappearance of elastic fibers from the dermis in the biopsied specimen. Because elastic fibers diminish in the late phase of blepharochalasis, we performed RT-PCR to analyze the mRNA expression of elastin, a major component of elastic fiber. Elastin mRNA expression in the patient's cultured fibroblasts had not decreased compared with that in the control fibroblasts. This result suggests that environmental factors or other matrix components of elastic fibers may be involved in the loss of elastic fiber.

Adult↗
PubMed2005

Primary anetoderma: a case report and its modified classification.

A fifty-nine-year-old healthy male presented with fifteen round pouches around his bilateral shoulders and proximal thighs, at which elasticity was lost on palpation. Histopathological examinations demonstrated that the lesional dermis was thinner than normal skin and there was loss of elastic fibers and mild inflammatory cell infiltration. Because there was no preceding inflammatory skin lesion or associated diseases, the patient was diagnosed with primary anetoderma. This is a rare case of primary anetoderma that showed loss of elastic fibers and the thinner dermis. In addition, a modified classification is proposed considering associated diseases with a review of literature.

Antibodies, Antiphospholipid↗
PubMed2005

Prognostic factor analysis for plaque psoriasis.

BACKGROUND: Little is known about the long-term prognostic factors which affect clinical outcomes after the diagnosis of psoriasis. OBJECTIVE: To identify the prognostic factors which predict long-term outcomes after diagnosis. METHODS: Patients' clinical characteristics at diagnosis were associated with long-term prognosis using the logistic regression method for 169 psoriasis patients (median follow-up time 11.6 years). RESULTS: The factors age > or =40 [odds ratio 0.27, 95% confidence interval (CI) 0.10-0.72, p = 0.0091], male (odds ratio 2.67, 95% CI 1.02-7.00,p = 0.0459) and BMI > or =25 (odds ratio 2.74, 95% CI 1.01-7.42, p = 0.0480) had significant effects on long-term prognosis after diagnosis. A simple prognostic index based on these factors was proposed. CONCLUSIONS: Three major prognostic factors were identified. The proposed index may be useful in the design of future clinical trials for psoriasis and in the selection of appropriate therapeutic approaches for individual patients.

Adolescent↗