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Biomedical subjects

Y Sugata

Publications and source records attributed to Y Sugata.

At least 19 recordsLinked to original sources
PubMed2006

Role of prostaglandin D2 and E2 terminal synthases in chronic rhinosinusitis.

BACKGROUND: Prostaglandin (PG)D(2) and E(2), two major cyclooxygenase (COX) products, are generated by PGD(2) synthase (PGDS) and PGE(2) synthase (PGES), respectively, and appear to mediate airway inflammation. OBJECTIVE: We sought to determine the role of PGDS and PGES in the pathophysiology of chronic rhinosinusitis (CRS). METHODS: The study examined the expression of PGDS and PGES in nasal polyps of 22 CRS patients. As controls, uncinate process mucosae were obtained from 12 CRS patients not having nasal polyps and five subjects without sinusitis. Immunohistochemistry and quantitative real-time PCR were used to evaluate the expression. RESULTS: Both PGDS and PGES were detected in nasal polyps by immunohistochemistry. Significantly greater levels of PGDS mRNA and lesser levels of PGES mRNA were observed in the nasal polyps as compared with uncinate process mucosae, and an inverse correlation between PGDS and PGES expression was observed. Levels of PGDS mRNA in nasal polyps were positively correlated with degree of infiltration by EG2+ eosinophils, whereas the levels of PGES were inversely correlated. Significantly increased levels of PGDS and conversely decreased levels of PGES were observed in asthmatics as compared with non-asthmatics. In addition, PGDS and PGES levels were positively and inversely correlated with the radiological severity of sinusitis, respectively. CONCLUSIONS: These results suggest that PGDS and PGES display an opposite and important role in the pathophysiology of CRS such as polyp formation, and more specifically, a biased expression of these synthases might contribute to the development of CRS by affecting eosinophilic inflammation.

Adolescent↗
PubMed2005

Nasal exposure to Staphylococcal enterotoxin enhances the development of allergic rhinitis in mice.

BACKGROUND: Staphylococcal enterotoxins (SEs) appear to play a role in the pathogenesis of allergic disease. However, little is known whether the nasal exposure to SE affects the development of allergic rhinitis (AR). OBJECTIVE: We sought to determine the in vivo effect of nasal exposure to SE on the development of AR using mouse model. METHODS: BALB/c mice were intranasally sensitized with Schistosoma mansoni egg antigen (SmEA) in the presence or absence of staphylococcal enterotoxin B (SEB). Control mice were intranasally sensitized with either SEB or SmEA alone. The production of antigen-specific antibodies including IgE, nasal eosinoplilia and cytokines by nasal mononuclear cells was compared among mice that had or had not received SEB treatment. RESULTS: Nasal exposure to SEB enhanced the development of AR in SmEA-sensitized mice, as manifested by SmEA-specific IgE production, nasal eosinophilia, and IL-4 and IL-5 production by nasal mononuclear cells after Ag challenge. This treatment also elicited IFN-gamma production by SmEA-primed cells. In addition, these mice produced SEB-specific IgE whereas mice treated with SEB without SmEA sensitization did not produce SEB-specific IgE or demonstrate nasal eosinophilia. CONCLUSION: These results suggest that the nasal exposure to SEB enhances susceptibility to AR although the exposure to SE solely does not induce AR.

Allergens↗
PubMed2005

Characterization of allergen-specific monocyte-derived dendritic cells generated from monocytes by a single-step procedure: effect on naïve and memory T cells.

BACKGROUND: Dendritic cells are one of the most potent antigen-presenting cells and when pulsed with allergen can modulate allergen-specific T-cell responses. We sought to establish a single-step method by which to generate allergen-specific monocyte-derived dendritic cells (MoDCs). METHODS: Dermatophagoides farinae (Df)-prepulsed MoDCs were generated from monocytes by culturing with Df in the presence interleukin (IL)-4, granulocyte-macrophage colony-stimulating factor (GM-CSF) and tumour necrosis factor (TNF)-alpha simultaneously. Df-prepulsed MoDC were incubated with autologous naive and memory T cells in the absence of recall antigen, then proliferation and cytokine production by T cells was determined. RESULTS: Generation of allergen-prepulsed MoDCs was confirmed by examining expression of surface molecules. Df-prepulsed MoDC selectively induced proliferation of Df-specific T cells in the absence of recall antigen. Under these conditions, Df-prepulsed MoDCs augmented but did not alter the cytokine production profile. In addition, Df-prepulsed MoDCs activated naive T cells leading to proliferation and selective production of IFN-gamma in allergic patients but not in healthy subjects. CONCLUSIONS: These results suggest that Df-prepulsed MoDC generated from monocytes by a simple single-step manipulation can induce Df-specific cellular responses from both naive and memory T cells in the absence of recall antigen, and these cells potentially can be utilized as immune adjuvants in allergen-specific immunotherapy.

Adult↗
PubMed2004

Roles of major oligosaccharides on Cry j 1 in human immunoglobulin E and T cell responses.

BACKGROUND: We have demonstrated that carbohydrates in Cry j 1, the major allergen of Cryptomeria japonica pollen, play a major role in promoting Cry j 1-specific Th2 response. However, little is known as to whether the carbohydrates directly participate in allergic responses. OBJECTIVE: We sought to determine whether Cry j 1-related oligosaccharides function as IgE and/or T cell epitopes. In addition, the regulatory effect of Cry j 1-related oligosaccharide on Cry j 1-specific T cell responses was investigated. METHODS: Two monovalent oligosaccharides largely found on Cry j 1, Manalpha1-6(Manalpha1-3)(Xylbeta1-2)Manbeta1-4GlcNAcbeta1-4(Fucalpha1-3)GlcNAc (M3FX), and GlcNAcbeta1-2Manalpha1-6(GlcNAcbeta1-2Manalpha1-3)(Xylbeta1-2)Manbeta1-4GlcNAcbeta1-4(Fucalpha1-3)GlcNAc (GN2M3FX) were prepared. Manalpha1-2Manalpha1-6(Manalpha1-2Manalpha1-3)Manalpha1-6(Manalpha1-2Manalpha1-2Manalpha1-3)Manbeta1-4GlcNAcbeta1-4GlcNAc (M9A) was used as control. Competitive inhibition ELISA for Cry j 1-specific IgE was performed using these oligosaccharides as inhibitors. In addition, T cell lines specific for Cry j 1 or purified protein derivative of Mycobacterium tubecurosis (PPD) were established, and cellular responses against these oligosaccharides were investigated in the presence or absence of the respective antigens. RESULTS: Overall, neither M3FX nor GN2M3FX displayed inhibitory effect on the binding between IgE and Cry j 1. In addition, M3FX did not by itself stimulate Cry j 1 or PPD-specific T cells. However, M3FX significantly inhibited Cry j 1-induced proliferation and IL-4 production in Cry j 1-specific T cells. Such an inhibitory effect was not seen in PPD-specific T cell responses. CONCLUSION: These results suggest that Cry j 1-related oligosaccharides are not major epitopes for IgE or T cells. However, these oligosaccharides have a novel potential to inhibit Cry j 1-specific T cell responses selectively.

Adolescent↗
PubMed2001

Two interactive genes responsible for a new inherited cataract (RCT) in the mouse.

We discovered a mutant mouse, RCT (Rinshoken cataract), with a new congenital cataract in strain SJL/J. The opacity of the lens associated with microphthalmia could be observed visually at 3 to 3.5 months of age. Marked degeneration of the lens, including loss of the fine structure of the lens fibers and swelling of epithelial cells with vacuoles of various sizes in the cortex, but no other defects except photoreceptor degeneration in the retina, was detected. Histological change in the lens was first observed at 2 days after birth. No sex-related differences were detected, and normal phenotypes in the F1 progeny of RCT and normal mice indicated that the cataract was recessive. The chromosomal location of the causative gene was determined by interval mapping by using intersubspecific backcross progeny of RCT and MSM/Ms, an inbred strain from the Japanese wild mouse Mus musculus molossinus. Backcross progeny were divided into three groups according to phenotype: mice (1) with an early-onset cataract, which can be detected visually as in RCT mice, (2) with a late-onset cataract, which can be detected histologically but not visually, and (3) with a normal lens. Three phenotypes were found to be expressed by allele combinations of two recessive genes, rct and mrct (a modifier of rct). The rct locus essential for the onset of the cataract was tightly linked to D4Mit278 on Chromosome (Chr) 4 with no recombination. The mrct locus was closely linked to D5Mit239 (chi2 = 66.3, P << 0.00001) on Chr 5.

Animals↗
PubMed1992

An application of ultrasonic tissue characterization to the diagnosis of cataract.

From a therapeutic and pathological point of view, it is important to classify types of cataract and to identify their stages. However, accepted criteria for quantitative diagnosis have not been established. On the other hand, based on the experience from tissue characterization applied to other clinical fields, the attenuation characteristics of the lens are expected to change according to the stage of disease and the type of cataract. In this study from echo signals we tried to measure the attenuation coefficient of the lens with the purpose of quantitatively diagnosing the cataract, and at an early stage. It is shown that the attenuation of the cataractous lens is larger than that of the normal lens and its value depends on the type of the cataract, an indication of the possibility of using tissue characterization in the evaluation of cataract.

Adult↗
PubMed1991

Electrophysiological study on a cochlear outer hair cell.

In order to examine the mechanoelectrical transduction of a cochlear hair cell, the electrical characteristics of the cochlear outer hair cell were studied. Both the cell dissociation technique and the patch clamp technique were used in this experiment. The membrane current gained by the voltage clamp method had a biphasic component, an initial inward current and a following outward current. After blocking the outward current by internal Cs ion and external TEA, the inward current has voltage-dependent inactivation. Also, the membrane potential change was studied by the current clamp method.

Action Potentials↗
PubMed1987

The morphological changes in the vestibular sensory epithelia following electrical stimulation.

The morphological changes of the vestibular sensory epithelia of the guinea pig following electrical stimulation were investigated using scanning electron microscope. Positive and negative square wave pulse stimulation was given through a silver ball electrode placed on the round window membrane for one hour. The current intensities used were 100, 200 and 300 microA. While the direct current stimulation at intensities of 100 or 200 microA did not cause any significant changes, severe damage of the utricular macula and the ampullar crista of the lateral semicircular canal was observed at 300 microA. The degenerative changes such as fusion of sensory hairs, protrusion of the cuticular plate and loss of sensory cells were found on both the utricle and the semicircular canal. In the most severely damaged area, the sensory epithelial surface was badly torn apart. In the clinical application of direct current to the inner ear for relieving tinnitus, special attention should be paid to the vestibular organ.

Acoustic Maculae↗
PubMed1985

[Objective tinnitus caused by myoclonus of the musculus tensor veli palitini].

Objective tinnitus is often caused by palatal myoclonus. We report a 15 years old boy with objective tinnitus in both ears and palatal myoclonus. He had myorhythmic movements of both tensor veli palatini muscles asynchronous with the objective tinnitus. The frequency of the clonus was 120 contractions a minute. The myoclonus and the objective tinnitus disappeared after division of the bilateral tensor veli palatini muscles.

Acoustic Impedance Tests↗
PubMed1984

An experimental study on a function of the cupula. Effect of cupula removal on the ampullary nerve action potential.

We used a posterior semicircular canal that had been isolated from a frog. From the utricular side the ampulla was cut open at a position one third of the way along the long axis. The cupula was removed through this opening using a glass micropipette. The action potential from the posterior ampullary nerve was recorded before and after removal of the cupula. After removal, the action potential disappeared almost completely. When the cupula was put back on the crista, the action potential was restored. When the cupula was put back upside down, the action potential recovered, but to a lesser extent.

Acoustic Stimulation↗