Publications by authors named "Takuya Ohta"

Basophils have nonredundant roles in various immune responses that require Ca influx. Here, we examined the role of two Ca sensors, stromal interaction molecule 1 and 2 (STIM1 and STIM2), in basophil activation. We found that loss of STIM1, but not STIM2, impaired basophil IL-4 production after stimulation with immunoglobulin E (IgE)-containing immune complexes.

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Ticks are blood-sucking arthropods that can transmit various pathogenic organisms to host animals and humans, causing serious infectious diseases including Lyme disease. Tick feeding induces innate and acquired immune responses in host animals, depending on the combination of different species of animals and ticks. Acquired tick resistance (ATR) can diminish the chance of pathogen transmission from infected ticks to the host.

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Ticks are blood-feeding arthropods that can transmit pathogens to humans and animals, leading to serious infectious diseases such as Lyme disease. After single or multiple tick infestation, some animal species develop resistance to tick feeding, leading to reduced risk of pathogen transmission. In mice infested with larval ticks, both mast cells and basophils reportedly play key roles in the manifestation of acquired tick resistance (ATR), but it remains ill-defined how they contribute to it.

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Ticks, blood-sucking arthropods, serve as vectors for transmission of infectious diseases including Lyme borreliosis. After tick infestation, several animal species can develop resistance to subsequent infestations, reducing the risk of transmission. In a mouse model, basophils reportedly infiltrate tick-feeding sites during the second but not first infestation and play a crucial role in the expression of acquired tick resistance.

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Mast cells undergo degranulation in response to various stimuli and rapidly release pre-formed mediators present in secretory granules, leading to immediate-type allergic reactions. Mast cell degranulation is commonly detected and quantified in vitro by measuring histamine or β-hexosaminidase released to culture medium. However, this type of assay cannot monitor degranulation of individual cells in real time, and it is not suitable for in vivo detection of degranulation.

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Anaphylaxis is a rapid-onset, life-threatening allergic reaction in that IgE, mast cells and histamine are commonly involved. It can be experimentally induced in IgE-sensitized animals by intravenous injection of corresponding allergens, and the sign of anaphylactic reaction can be detected within minutes after allergen challenge. However, it remains puzzling why the anaphylactic reaction can be initiated in vivo so quickly, considering that allergens are delivered into the blood circulation while mast cells reside within peripheral tissues but not in the blood circulation.

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When a core level is excited by circularly polarized light, the angular momentum of light is transferred to the emitted photoelectron, which can be confirmed by the parallax shift of the forward focusing peak (FFP) direction in a stereograph of atomic arrangement. No angular momentum has been believed to be transferred to normal Auger electrons resulting from the decay process filling core hole after photoelectron ejection. We succeeded in detecting a non-negligible circular dichroism contrast in a normal Auger electron diffraction from a nonmagnetic Cu(001) surface far off from the absorption threshold.

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Open angle glaucoma, a slowly progressive optic atrophy, is clinically characterized by visual field defects corresponding to excavation of the optic disc, called glaucomatous cupping. Open angle glaucoma is further divided into primary open angle glaucoma caused by elevated intraocular pressure (higher than the normal limit of 21 mmHg), and normal tension glaucoma, in which intraocular pressure is in the normal range. Here we report a case of normal tension glaucoma associated with Buerger's disease, also known as thromboangiitis obliterans, which causes systemic blood flow disturbance.

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Purpose: We examined the activity of gemcitabine against neuroblastoma in vitro and in vivo. In addition, we investigated the cellular mechanisms of high sensitivity to the agent in neuroblastoma cells.

Experimental Design: We examined 11 neuroblastoma cell lines for sensitivity to gemcitabine and other chemotherapeutic agents used clinically for neuroblastoma.

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Cytarabine (araC) is a highly active antimetabolite against hematological malignancy while the agent shows limited activity against carcinomas. In this study, we focused on cellular transport and catalysis of the nucleoside in order to elucidate the mechanism of intrinsic resistance to araC in carcinomas. Activities of two metabolizing enzymes for araC, deoxycytidine kinase (DCK) and cytidine deaminase (CDA), and cellular transport of the agent were examined in 9 carcinoma cell lines.

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