Yurika Yamate

Osaka City University, Ōsaka, Ōsaka, Japan

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Publications (14)29.49 Total impact

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    ABSTRACT: BackgroundUVA irradiation before allergic sensitization induces immunosuppression, but the percise mechanism remained unclear. In this study, we examined the influence of UVA irradiation of the eye on contact hypersensitivity (CHS) and the role of mast cells in CHS.Methods We used two types of haptens, fluorescein isothiocyanate (FITC: a Th2 type hapten) and 4-ethoxymethylene-2-phenyl-2-oxazolin-5-one (oxazolone: a Th1 type hapten). A 300 kJ/m2 dose of UVA irradiation was delivered to the eyes. After UVA irradiation, we sensitized abdominal shaved skin, and challenged the ear epidermis and colons of these mice with each hapten.ResultsAfter UVA irradiation, the CHS of the skin and colon were not inhibited in the FITC-sensitized mice. However, in the oxazolone-sensitized mice, only the CHS of the skin was inhibited by UVA irradiation. The inflammation of the colon became more severe after UVA irradiation. In mast cell deficient (W/Wv) mice sensitized to FITC, the CHS was weaker than that in WT mice. Moreover, the reduction of immunosuppression in ear swelling was seen for one of the two models they used.Conclusions These results suggest that the mast cells induced by UVA irradiation of the eye have different roles in the epidermis and colon, and have different responses to different haptens.
    Photodermatology Photoimmunology and Photomedicine 12/2014; · 1.52 Impact Factor
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    ABSTRACT: Abstract Context: It has been reported that chronic sennoside use is associated with the development of melanosis coli, colonic adenoma, and/or carcinomas. Objectives: In this study, we investigated the immunological changes in the colon and skin after the administration of senna. Materials and methods: In this study, we investigated the colon and epidermis of C57/BL6j mice after a single administration of 10 mg/kg of senna [Cassia angustifolia (Caesalpiniaceae); 3, 6, 12, and 24 h after administration] and after repeated once per week administrations (on days 3, 5, 7, 14, and 21 of administration). The LD50 and ED50 of senna used in this experiment were 165 mg/kg and 13 g/kg, respectively. Results: We demonstrated that the DOPA-positive cells in the colon increased at 12 h after single administration and were further increased from at 5-28 d after repeated administration. We also studied the physiological changes of the small intestine using the charcoal meal test. We found that there was a tendency for peristalsis to be inhibited after repeated senna administration. In the epidermis, we investigated the number of Langerhans cells, because they are important immune cells of the skin. The number of these cells decreased, especially after repeated administration. Discussion and conclusion: The present findings suggested that it is necessary to pay attention to not only the intestine but also the skin, during long-term senna treatment.
    Pharmaceutical Biology 11/2014; · 1.21 Impact Factor
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    ABSTRACT: Background It is known that the levels of hormones secreted from the pituitary gland are increased by ultraviolet B (UVB) eye irradiation. The ovaries are affected by the hormones secreted from the pituitary gland. Therefore, we observed the influence of UVB eye irradiation on the ovaries.Methods In this study, a 2.5 kJ/m2 dose of UVB irradiation was delivered by a sunlamp to the eye or the ear of C57BL/6j female mice. Five days after UVB irradiation, we removed the ovaries.ResultsThe plasma levels of α-melanocyte-stimulating hormone (α-MSH), adrenocorticotropic hormone (ACTH) and β-endorphin were increased 24 hours after UVB irradiation of either the eye or the ear. The amounts of ACTH and α-MSH were decreased five days after UVB irradiation. However, the β-endorphin level five days after UVB eye irradiation did not decrease. In addition, UVB eye irradiation increased the expression of Dopa-positive cells, tyrosinase and dopa decarboxylase (DDC), and also increased the immunoreactivity of melanocortin-1 receptor in the ovaries. The dopamine content in the plasma was also increased.Conclusions These results suggest that the melanin and dopamine systems of the ovary are affected by UVB eye irradiation, and the synthesized dopamine is maintained at high levels as β-endorphin.
    Photodermatology Photoimmunology and Photomedicine 10/2014; · 1.52 Impact Factor
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    ABSTRACT: Background Tranexamic acid (trans-4-aminomethylcyclohexanecarboxylic acid) is a medicinal amino acid used in skin whitening care. This study examined the effects of tranexamic acid on the melanocyte activation of the skin induced by an ultraviolet (UV) B eye irradiation.Methods The eye or ear was locally exposed to UVB at a dose of 1.0 kJ/m2 using a 20SE sunlamp after covering the remaining body surface with aluminum foil.ResultsUVB eye irradiation induced melanocyte activation of the skin, similar to that observed following UVB ear irradiation, which was suppressed by the administration of tranexamic acid treatment. The plasma α-melanocyte-stimulating hormone (α-MSH) content was increased by UVB irradiation of the eye; however, the increase in α-MSH was suppressed by tranexamic acid treatment. In addition, UVB eye irradiation induced the up-regulation of prohormone convertase (PC) 2 in the pituitary gland. Meanwhile, the increase in PC2 induced by UVB eye irradiation was suppressed by tranexamic acid treatment.Conclusions These results clearly indicate that tranexamic acid decreases the expression of PC2, which cleavages from proopiomelanocortin to α-MSH in the pituitary gland, thereby suppressing melanocyte activation.
    Photodermatology Photoimmunology and Photomedicine 07/2014; · 1.52 Impact Factor
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    ABSTRACT: Background.  In previous studies, we made the unexpected finding that in mice, ultraviolet (UV)B irradiation of the eye increased the concentration of α-melanocyte-stimulating hormone (α-MSH) in plasma, and systemically stimulated epidermal melanocytes. Aims.  To compare the extent of the pigmentation induced by social and restraint stress (which activate the hippocampus-pituitary system) with that induced by UVB irradiation. Methods.  DBA/2 and sham-operated or hypophysectomized DBA/2 mice were subjected to local UVB exposure using a sunlamp directed at the eye, and two types of stress (social and restraint) were imposed. Results.  UVB irradiation of the eye or exposure to stress loading both increased the number of Dopa-positive melanocytes in the epidermis, and hypophysectomy strongly inhibited the UVB-induced and stress-induced stimulation of melanocytes. Irradiation of the eye caused a much greater increase in dopamine than did the stress load. Both UVB eye irradiation and stress increased the blood levels of α-MSH and adrenocorticotropic hormone (ACTH). In addition, the increase in plasma α-MSH was greater in animals subjected to UVB eye irradiation than in those subjected to stress loading, whereas the reverse occurred for plasma ACTH. UVB irradiation to the eye and stress loading increased the expression of prohormone convertase (PC)1/3 and PC2 in the pituitary gland. The increase in expression of pituitary PC2 was greater in animals subjected to UVB eye irradiation than to stress, whereas no difference was seen between the two groups for the increase in PC1/3. Conclusions.  UVB eye irradiation exerts a stronger effect on pigmentation than stress loading, and is related to increased levels of α-MSH and PC2.
    Clinical and Experimental Dermatology 01/2013; 38(1):71-6. · 1.33 Impact Factor
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    ABSTRACT: Ultraviolet B (UVB) radiation induces inflammation in the skin specifically at the site of exposure. We unexpectedly found that UVB-induced inflammation was not induced in gp91phox-depleted mice. To test whether gp91phox is directly involved in UVB-induced inflammation, neutrophil- and hyaluronic acid-depleted mice were also irradiated and examined for their response. Hyaluronic acid-depleted mice showed strongly inhibited UVB-induced inflammation, but the neutrophil-depleted mice did not exhibit any suppressed UVB-induced inflammation. To elucidate the pathway by which UVB irradiation induced inflammation, we examined the expression of nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-3 (NLRP3) and caspase-1 in the mouse skin. An increase in the expression of NLRP3 and caspase-1 was seen following the UVB irradiation of C57BL mice; however, the UVB-irradiated gp91phox-knockout (gp91phox(-/-) ) mice did not have this increase in expression. Furthermore, the plasma IL-1β level increased after the UVB irradiation in C57BL mice, but there was no change in the gp91phox(-/-) mice. These results clearly indicate that nicotinamide adenine dinucleotide phosphate oxidase is activated by gp91phox, which is expressed on the surface in response to the increased expression of hyaluronic acid induced by UVB irradiation, and as result, the generation of reactive oxygen species (ROS) increases. This ROS activate NLRP3, and NLRP3 leads to the production of caspase-1, which subsequently increases IL-1β, thereby finally inducing inflammation. It is thought that this system may play an important role in the damage and ageing of skin, and further studies are necessary to confirm these finding.
    Experimental Dermatology 12/2012; 21(12):911-4. · 3.58 Impact Factor
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    ABSTRACT: PURPOSE: Irradiation by ultraviolet (UV) B is known to increase the number of Dopa-positive melanocytes in the skin. This study examines the effectiveness of a contact lens for the defense of UVB eye irradiation-induced pigmentation. METHODS: A 2.5kJ/m(2) dose of UVB radiation was delivered by a sunlamp to the eye of C57BL/6j male mice, and changes in the expression of Dopa-positive melanocytes in the epidermis and the plasma level of alpha-melanocyte-stimulating hormone (α-MSH) was analyzed. RESULTS: The degree of change in the Dopa-positive melanocytes expression was reduced by UVB blocking contact lens using mice given UVB irradiation to the eye. The plasma level of α-MSH increased in the C57BL/6j mice after irradiation to the eye, but there was no increase in the UVB blocking contact lens mice given UVB irradiation to the eye. Both the increase of the expression of Dopa-positive melanocytes and the plasma level of α-MSH were strongly suppressed by an alignment fitting UVB blocking contact lens and only a slightly suspended UVB blocking contact lens. In addition, these changes were successfully inhibited by a UVB blocking contact lens but not by a non-UVB blocking contact lens with a similar absorbance. CONCLUSION: These observations suggest that the UVB blocking contact lens inhibits the pigmentation of the epidermis in mice by suppressing of the α-MSH.
    Contact lens & anterior eye: the journal of the British Contact Lens Association 10/2012;
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    ABSTRACT: Seirogan, a wood creosote, has been used as an antidiarrhetic drug in Asian countries including Japan for many years. This antidiarrhetic has recently been used as a sugar-coated pill because Seirogan has a strong smell. The strong smell of the uncoated form of Seirogan may modulate the defense systems of animals because the sense of smell is important for the detection of toxic metabolites in foods contaminated with pathogens. This study examined the effect of the sugar-coated and uncoated forms of this antidiarrhetic on the immunological response and inflammatory reactions in mice that had been sensitized with either fluorescein isothiocyanate or oxazolone. The sensitization of mice with either FITC or oxazolone markedly increased the plasma levels of tumor necrosis factor-α and mucosal IgA and elicited severe inflammation in the colon by a mechanism that could be suppressed by exposure of animals to the smell of uncoated Seirogan as effectively as the oral administration of the agent. Dermal inflammation in the FITC- and oxazolone-sensitized mice was also suppressed effectively either by the exposure to the smell or oral administration of the agent. Biochemical and histochemical analyses revealed that the elevated levels of plasma tumor necrosis factor-α and mucosal IgA were significantly decreased by exposure to the smell of uncoated Seirogan as well as by oral administration of the agent. Exposure of mice to the smell of Seirogan but not oral administration of the agent selectively increased plasma levels of adrenocorticotropic hormone and cortisol, particularly in the sensitized animals. These observations suggest that exposing the animals to the smell of Seirogan per se activated the hypothalamo-pituitary-adrenal axis and systemically modulated immunological reactions to suppress the allergic reactions.
    Journal of Clinical Biochemistry and Nutrition 09/2012; 51(2):91-5. · 2.25 Impact Factor
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    ABSTRACT: Irradiation by long-term ultraviolet (UV) A initiates the induction of photoaging. However, the mechanisms responsible for the structural changes of skin induced by UVA irradiation of the eye are still unknown. Male hairless mice were used in this study. The eye or dorsal skin was locally exposed to UVA after covering the remaining body surface with aluminum foil at a dose of 110 kJ/m(2) using a FL20SBLB-A lamp for 60 days. The plasma α-melanocyte stimulating hormone (α-MSH), nitrogen oxides (NO(2)/NO(3)), tumor necrosis factor-α (TNF-α), and the prostaglandin E(2) (PGE(2)) content all increased after UVA irradiation. The levels of NO(2)/NO(3), TNF-α, and PGE(2) also increased more after UVA skin irradiation than after UVA eye irradiation. However, the level of α-MSH increased more by eye irradiation than skin irradiation. In addition, UVA irradiation of the eye and dorsal skin increased the number of mast cells and fibroblasts. Furthermore, the expression of the melanocortin-1 receptor (MC1R) was increased on the fibroblast surface by UVA irradiation of the eye. These results indicate that the signal evoked by UVA irradiation of the eye, through the hypothalamo-pituitary proopiomelanocortin system, up-regulated the production of α-MSH. This hormone controls the collagen generation from fibroblasts, thus suggesting that photoaging was induced by UVA irradiation of the eye.
    Archives for Dermatological Research 01/2012; 304(1):39-45. · 2.71 Impact Factor
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    ABSTRACT: Mite antigens play important roles in the pathogenesis of atopic dermatitis (AD). We recently developed a novel air cleaner (KC-850U) using charged plasma cluster ions to eliminate a variety of allergens from house environments. The present work demonstrates the ability of KC-850U to decrease the symptoms of AD induced by mite allergens. Pooled sera from the conventional NC/Nga mice, and AD model animals, were incubated with varying concentrations of the control and KC-850U-pretreated allergens extracted from mite. The incubated mixtures were transferred to wells coated with intact allergens and subjected to ELISA to measure the amounts of immunoglobulin E (IgE) bound to the wells. Kinetic analysis revealed that exposure of mite extracts to plasma cluster ions destructed about 95% of the epitopes of the allergens. The specific pathogen-free and conventional mice were housed in rooms equipped with either KC-850U or a standard air cleaner and observed their dermal symptom for 2 weeks. Dermatological examination revealed the AD symptom of the conventional mice housed in a room equipped with an air cleaner. In contrast, the symptoms which became apparent during the experiments were suppressed remarkably exposing mice to plasma cluster ions. These observations suggested that plasma cluster ions generated by KC-850U destroyed the epitopes of mite allergens and suppressed the symptoms of AD in the mice.
    Archives for Dermatological Research 11/2010; 303(5):367-70. · 2.71 Impact Factor
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    ABSTRACT: We previously reported that topical irradiation of the eye by ultraviolet-B (UVB) activated hypothalamo-pituitary-adrenal axis (HPA-A) of the mouse to increase 3, 4-dihydroxyphenylalanine (DOPA)-positive melanocytes in the skin by an inducible nitric oxide synthase (iNOS)-dependent mechanism. This work demonstrates that irradiation of the eye by ultraviolet-A (UVA) specifically increased DOPA-positive cells in the mucosa of the jejunum and colon of C57BL/6J mice by some HPA- and iNOS-independent mechanism. UVA-induced increase in DOPA-positive cells in the intestine was inhibited by the administration of hexamethonium or prazosin plus propranolol, blockers for the sympathetic nervous system. UVA irradiation of the eye increased DOPA- and histidine decarboxylase (HDC)-positive cells in the intestinal mucosa of both C57BL/6J and WBB6F1/J mice but not in the mutant strain W/Wv of the latter that lack mast cells. UVA irradiation of the eye suppressed the intestinal peristalsis of control, hypophysectomized or iNOS(-/-) C57BL/6J mice by the mechanism that was inhibited by hexamethonium or prazosin plus propranolol. These observations suggest that UVA irradiation of the eye stimulated the sympathetic nervous system to increase the mucosal DOPA- and HDC-positive mast cells and suppressed the peristalsis of the small intestine of the mouse.
    Photochemistry and Photobiology 09/2010; 87(1):191-8. · 2.29 Impact Factor
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    ABSTRACT: It has been well documented that a long-time irradiation of the eye by a strong light elicits eyestrain and fatigue. To elucidate the mechanism for the induction of light-induced fatigue and asthenopia, changes in the mouse were analyzed after white light-irradiation to the eye. C57BL/6j male mice were irradiated with white light in a specially designed room equipped with four mirrors covering all areas of its four walls to elicit diffused reflected light, and changes in their plasma levels of cortisol, INF-gamma, interleukin-10 (IL-10) and transforming growth factor-beta (TGF-beta) were analyzed. Irradiation of mice with scattered white light significantly decreased the motional activity of animals, suggesting the occurrence of fatigue. Biochemical analysis and enzyme-immunoassay revealed that the irradiation of mice significantly elevated the plasma levels of cortisol, IFN-gamma, IL-10 and TGF-beta. All these changes were not observed with mice irradiated with the light in a similar room not equipped with mirrors. These changes were successfully inhibited by a polarized glass filter but not by a non-polarized filter with a similar absorbance. These observations suggest that irradiation of the eye by scattered reflected light stimulated a stress response via hypothalamo-pituitary-adrenal axis to enhance the secretion of cortisol from the adrenal grand and increase the plasma levels of cytokines.
    Photodermatology Photoimmunology and Photomedicine 04/2010; 26(2):89-92. · 1.52 Impact Factor
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    ABSTRACT: Because AA (L-ascorbic acid) scavenges various types of free radicals to form MDAA (monodehydroascorbic acid) and DAA (dehydroascorbic acid), its regeneration from the oxidized metabolites is critically important for humans and other animals that lack the ability to synthesize this antioxidant. To study the dynamic aspects of AA metabolism in the circulation, a long acting AOase (ascorbate oxidase) derivative was synthesized by covalently linking PEG [poly(ethylene glycol)] to the enzyme. Fairly low concentrations of the modified enzyme (PEG-AOase) rapidly decreased AA levels in isolated fresh plasma and blood samples with a concomitant increase in their levels of MDAA and DAA. In contrast, relatively high doses of PEG-AOase were required to decrease the circulating plasma AA levels of both normal rats and ODS (osteogenic disorder Shionogi) rats that lack the ability to synthesize AA. Administration of 50 units of PEG-AOase/kg of body weight rapidly decreased AA levels in plasma and the kidney without affecting the levels in other tissues, such as the liver, brain, lung, adrenal grand and skeletal muscles. PEG-AOase slightly, but significantly, decreased glutathione (GSH) levels in the liver without affecting those in other tissues. Suppression of hepatic synthesis of GSH by administration of BSO [L-buthionin-(S,R)-sulfoximine] enhanced the PEG-AOase-induced decrease in plasma AA levels. These and other results suggest that the circulating AA is reductively regenerated from MDAA extremely rapidly and that hepatic GSH plays important roles in the regeneration of this antioxidant.
    Biochemical Journal 05/2009; 421(2):293-9. · 4.65 Impact Factor
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    ABSTRACT: Irradiation by ultraviolet A (UVA) initiates the suppression of skin contact hypersensitivity. However, the change in the whole body immunity by UVA irradiation of the eye is still unknown. The mice used in this study were separated into four groups namely: a control, UVA irradiation of the eye, UVA irradiation of the ear, UVA irradiation of the eye + a glucocorticoid receptor antagonist (RU-486) administrated, UVA irradiation of the eye with an adrenalectomy and non-irradiation + cortisol administrated groups. The eye or ear was locally exposed to UVA after covering the remaining body surface with aluminum foil at a dose of 110 kJ/m(2) using a FL20SBLB-A lamp. Plasma adrenocorticotropic hormone, cortisol, and interleukin-10 (IL-10) content increased by UVA irradiation of the eye. In addition, UVA irradiation of the eye induced down-regulation of the epidermal Langerhans cells in the ear and the up-regulation of the mucosal immunoglobulin A (IgA) in the intestine. However, the changes in the epidermal Langerhans cells and mucosal IgA of UVA irradiation of the eye are not induced either by the RU-486 treatment or an adrenalectomy. These results clearly indicate that the signal evoked by UVA irradiation of the eye, through the hypothalamo-pituitary-adrenal pathway, up-regulated the production of glucocorticosterone. This hormone controls immunity, and the possibility that it performed a living body defense for UVA exposure was thus suggested.
    Archives for Dermatological Research 02/2009; 301(3):239-44. · 2.71 Impact Factor