Yasuhiro Samejima

Human eotaxin induces eosinophil-derived neurotoxin release from normal human eosinophils

Background: Eosinophil granule proteins deposition at the site of allergic inflammation contributes to the late-phase reaction of hypersensitivity diseases. In the present communication, we describe the effect of human eotaxin on normal human eosinophil exocytosis measured as degranulation of eosinophil-derived neurotoxin (EDN). Methods: Purified eosinophils were obtained from normal healthy volunteers with the CD16-negative procedure. Purified eosinophils were stimulated with various concentrations of eotaxin and the amount of EDN released was analysed by radioimmunoassay. Flow cytometry was used to examine the surface expression of adhesion molecules on eosinophils. Results: Eotaxin significantly induced EDN release in a dose-dependent manner. The potency of eotaxin in this effect was equal to that of RANTES, and comparable to that of platelet-activating factor. Eotaxin-induced EDN release was blocked by cytochalasin B in a dose-dependent manner. The surface expression of CD11a, CD11b, CD18 and VLA-4 adhesion molecules on normal human eosinophils were not modulated by eotaxin stimulation. Conclusions: These results indicate that eotaxin may play an important role not only as a selective chemotaxin for the cell type but also as a secretagogue. Furthermore, they demonstrate a degranulation mechanism(s) involving cytoskeletal changes which is probably independent of the quantitative expression of adhesion molecules.

Effects of PAF on histamine H1 receptor mRNA expression in rat trigeminal ganglia.

The application of platelet-activating factor (PAF) to the nasal mucosa of humans has been shown to increase histamine-induced hyper-reactivity. To test the hypothesis that PAF acts by increasing the reactivity of sensory nerve endings in the nasal mucosa to histamine, we examined PAF-stimulated rat trigeminal nerve ganglion cells. We found that relatively low concentrations of PAF (10(-12)-10(-9) M) induced increased histamine H1 receptor mRNA expression. This increase appeared as early as 1 h after PAF stimulation, peaked at 4 h, and disappeared after 24 h. The PAF receptor antagonist WEB2086 inhibited the increased expression of histamine H1 receptor mRNA induced by PAF, suggesting that the effects of PAF are mediated by specific receptors. This PAF effect was abolished by actinomycin D, suggesting that PAF induces de novo transcription of histamine H1 and/or PAF receptor mRNA. PAF may be important in the hyper-responsiveness of nasal mucosa exposed to histamine.

Inhibition of Human Eosinophil Chemotaxis in Vitro by the Anti-Allergic Agent Emedastine Difumarate

Emedastine difumarate (emedastine), an anti-allergic agent with anti-histaminic properties, was studied for its effect on human eosinophil chemotaxis induced by platelet activating factor (PAF). Peripheral blood eosinophils (98% purity) were obtained from healthy donors and chemotaxis assay were performed in microchemotaxis chambers. Emedastine showed a significant inhibitory effect on 10(-6) M PAF-induced eosinophil chemotaxis, in dose dependent fashion, at concentrations from 10(-6) to 10(-8) M. Conversely, no inhibitory effect was observed on human neutrophil chemotaxis. Pretreatment of eosinophils with Pyrilamine did not affect PAF-induced eosinophil chemotaxis. Thus emedastine appears to possess a potent and selective inhibitory effect on eosinophils chemotaxis, an action which is probably unrelated to its anti-histamine properties.

Swallowing pressure and pressure profiles in young healthy adults

To measure the swallowing pressure (SP) of normal subjects using a 2.64‐mm‐diameter high‐resolution manometry (HRM) catheter with 36 circumferential sensors.

Modulation of Normal Human Eosinophil Chemotaxis in vitro by Herbimycin A, Erbstatin and Pervanadate

Background: The mediators involved in eosinophil accumulation in diseases such as allergy continue to be an area of interest, even though little is known regarding the signaling involved in the human cell type recruitment. In the present study, we demonstrate a novel modulatory role of tyrosine kinase and tyrosine phosphatase activities on normal human eosinophil chemotaxis induced by different groups of chemoattractant. Methods: Purified eosinophils were obtained from normal healthy volunteers with the CD16-negative procedure. Chemotactic activities against platelet-activating factor (PAF), vasoactive intestinal peptide (VIP) and eotaxin were assessed using a 48-well microchemotaxis chamber assay. Purified eosinophils were pretreated with herbimycin A, erbastatin or pervanadate to examine the role of tyrosine kinase in chemoattractant signaling. Results: Pretreatment of eosinophils with the tyrosine kinase inhibitors herbimycin A and erbstatin significantly blocked chemotaxis induced by eotaxin whilst both inhibitors augmented chemotaxis induced by VIP; however, they had no effect on PAF-induced chemotaxis. On the other hand, pretreatment of eosinophils with the phosphotyrosine phosphatase inhibitor pervanadate resulted in augmentation of eotaxin-induced chemotaxis and inhibition of VIP-induced chemotaxis, but it had no effect on PAF-induced chemotaxis. Conclusions: These results suggest that protein kinase plays a modulatory role in eosinophil chemotaxis induced by various chemoattractants.

Muscarinic Acetylcholine Receptors on Human Lymphocytes in Patients with Meniere's Disease

To investigate patients with Menières disease and the association of cholinergic hyperreactivity, we performed muscarinic acetylcholine receptor assay using peripheral blood lymphocytes from patients with Menières disease and non-dizzy, non-allergic control subjects. Cholinergic receptor maximal bindings (Bmax) and dissociation constants (Kd) were compared between the two groups, indicating the number and the affinities of the receptors, respectively. The receptor Bmax value in Meniéres patients during the remission state (108.6 +/- 51.2 fmol/l x 10(6) lymphocytes) was higher than that in normal controls (45.8 +/- 9.2 fmol/l x 10(6) lymphocytes) (p < 0.01). Furthermore, during an exacerbated state, Bmax was increased significantly (223.7 +/- 90.2 fmol/l x 10(6) lymphocytes) compared to the remission state (p < 0.01). In contrast, Kd values for the receptor did not differ between the two groups. These results suggest that patients with Menières disease have cholinergic hyperreactivity, which may be further upregulated during a state of exacerbation due to an increase in the number of cholinergic receptors.

Nasal tissue eosinophils in allergic rhinitis

The density characteristics and functional heterogeneity of nasal tissue eosinophils were studied. The density distribution profiles of eosinophils from patients with allergic rhinitis (AR) showed peaks at densities of 1.068 to 1.084 g/ml, significantly lower than the densities of eosinophils in non-allergic patients with nasal polyps and chronic sinusitis (p < 0.01). The proportion of hypodense eosinophils in patients with AR was 43%; this was significantly greater than that in non-allergic subjects (p < 0.001). Patients with AR tended to have more EG2-positive tissue eosinophils. Furthermore, normodense eosinophils in nasal tissue tended to show a higher percentage of EG2-positive cells than hypodense eosinophils. On the other hand, circulating hypodense eosinophils showed a higher percentage of EG2-positive cells than normal density eosinophils. These results suggest that tissue eosinophils may be activated, and that the functional heterogeneity of eosinophils is dependent on factors other than cell density.

Transepithelial migration of eosinophils in experimental nasal allergy in guinea pigs

We examined eosinophil-migration through the nasal epithelium into nasal cavity in a guinea pig model exhibiting 8-day passive cutaneous anaphylaxis antibody-dependent nasal allergy. Transmission electron microscopic observation of this process revealed that eosinophils traversed the epithelium through the intercellular space and split the tight-junctions of epithelial lining cells. Freeze-fracture studies of this process showed that the morphology of tight-junction was not changed after eosinophil-migration. These observations may indicate that tight-junctions close after eosinophil-migration.

Postdeglutitive residue in idiopathic unilateral vocal fold paralysis: a quantitative videofluoroscopic study.

To quantitate postdeglutitive residue and determine its association with paralysis duration (≤6 vs. ≥6 months) in patients with idiopathic unilateral vocal fold paralysis (UVFP).

Heterogeneous eosinophils of allergic rhinitis in chemotactic response

Chemotactic responses of eosinophils from patients with allergic rhinitis to 5 STO-2-derived eosinophil chemotactic factors (ECF), IL-3, IL-5 and GM-CSF were examined. The patients were divided into two groups: patients with perennial allergic rhinitis sensitive to Dermatophagoides farinae and those with seasonal allergic rhinitis sensitive to Japanese cedar pollen. There was no essential difference between chemotactic response of eosinophils from the former to STO-2-derived ECF and that from healthy individuals. However, eosinophils from patients with seasonal allergic rhinitis failed to respond to one of the STO-2-derived ECFs, ECF-P19. Before and after nasal antigen provocation, no change occurred in the chemotactic profiles. Furthermore, we found that eosinophils from both types of patients with allergic rhinitis responded not only to IL-3 and GM-CSF but also to IL-5 unlike those of healthy individuals.