A Rare Case of Palpebral Cellulitis, a Variation of Pott's Puffy Tumor.

A rare case of palpebral cellulitis with simultaneous frontal sinusitis and osteomyelitis is reported. A healthy 45-year-old man presented with left upper eyelid swelling. He was given intravenous meropenem at the local hospital, but he failed to improve. Magnetic resonance imaging showed left frontal and maxillary sinusitis and upper palpebral cellulitis with an abscess. His temperature was 37.6°C, C-reactive protein was 1.36 mg/dL, thyroid hormone was elevated, left best-corrected visual activity was 1.2, and intraocular pressure was 25 mm Hg. He was then given cefazolin intravenously for 3 days but with no improvement. Therefore, the eyelid skin was incised. Postoperatively, the swelling improved significantly. Computed tomography demonstrated osteomyelitis of the left frontal sinus and osteolysis of the inferior wall. This case was considered a variation of Pott's puffy tumor. Bacterial cultures from the cellulitis abscess and sinusitis were negative. As for sinusitis, endoscopic sinusitis surgery (frontal sinus single sinus surgery [Draf III] and Kilian surgery) was performed. During 10 months of follow-up after the skin incision, no signs of recurrent eyelid swelling were observed.

Transplantation of Olfactory Stem Cells with Biodegradable Hydrogel Accelerates Facial Nerve Regeneration After Crush Injury.

Olfactory mucosa contains neural stem cells, called olfactory stem cells (OSCs), which produce trophic support required for promoting axonal regeneration after nerve injury. However, the local tissue environment can reduce the viability/function of transplanted cells when placed directly on the injury. Although gelatin hydrogels have been shown to aid cell survival during transplantation, such OSC-hydrogel combinations have not been extensively tested, particularly during recovery from facial nerve palsy. In this study, OSCs were isolated from the olfactory mucosae of newborn mice and were shown to express neural stem cell markers before differentiation, as well as cell-type specific markers after differentiation, confirming their multipotency. The OSCs also secrete growth factors and various cytokines that promote nerve regeneration. To test the effects of OSC transplantation in vivo, Medgel, a biodegradable hydrogel sponge, was applied to retain OSCs around the injury site and to lessen the detrimental effects of the local environment in an established facial nerve palsy mouse model. When OSCs were transplanted into the injury site, accelerated recovery was observed for 1 week. When OSCs were transplanted with Medgel, a higher level and duration of accelerated recovery was observed. OSCs in Medgel also increased peripheral nerve function and increased the number of regenerated nerve fibers. These results suggest that OSCs implanted with Medgel accelerate and enhance recovery from facial palsy in mice. Because human OSCs can be easily obtained from olfactory mucosa biopsies with limited risk, this OSC-Medgel combination is a candidate treatment option for accelerating recovery after facial nerve injury. Stem Cells Translational Medicine 2019;8:169&10.

Similar structural stabilities of 3-isopropylmalate dehydrogenases from the obligatory piezophilic bacterium Shewanella benthica strain DB21MT-2 and its atmospheric congener S. oneidensis strain MR-1.

We previously found that the enzymatic activity of 3-isopropylmalate dehydrogenase from the obligatory piezophilic bacterium Shewanella benthica strain DB21MT-2 (SbIPMDH) was pressure-tolerant up to 100 MPa, but that from its atmospheric congener S. oneidensis strain MR-1 (SoIPMDH) was pressure-sensitive. Such characteristics were determined by only one amino acid residue at position 266, serine (SoIPMDH) or alanine (SbIPMDH) [Y. Hamajima et al. Extremophiles 20: 177, 2016]. In this study, we investigated the structural stability of these enzymes. At pH 7.6, SoIPMDH was slightly more stable against hydrostatic pressure than SbIPMDH, contrary to the physiological pressures of their normal environments. Pressure unfolding of these IPMDHs followed a two-state unfolding model between a native dimer and two unfolded monomers, and the dimer structure was pressure-tolerant up to 200 MPa, employing a midpoint pressure of 245.3 ±â€¯0.1 MPa and a volume change of -225 ±â€¯24 mL mol-1 for the most unstable mutant, SbIPMDH A266S. Thus, their pressure-dependent activity did not originate from structural perturbations such as unfolding or dimer dissociation. Conversely, urea-induced unfolding of these IPMDHs followed a three-state unfolding model, including a dimer intermediate. Interestingly, the first transition was strongly pH-dependent but pressure-independent; however, the second transition showed the opposite pattern. Obtained volume changes due to urea-induced unfolding were almost equal for both IPMDHs, approximately +10 and -30 mL mol-1 for intermediate formation and dimer dissociation, respectively. These results indicated that both IPMDHs have similar structural stability, and a pressure-adaptation mechanism was provided for only the enzymatic activity of SbIPMDH.

Mechanistic Insights into the Activation of Soluble Guanylate Cyclase by Carbon Monoxide: A Multistep Mechanism Proposed for the BAY 41-2272 Induced Formation of 5-Coordinate CO-Heme.

Soluble guanylate cyclase (sGC) is a heme-containing enzyme that catalyzes cGMP production upon sensing NO. While the CO adduct, sGC-CO, is much less active, the allosteric regulator BAY 41-2272 stimulates the cGMP productivity to the same extent as that of sGC-NO. The stimulatory effect has been thought to be likely associated with Fe-His bond cleavage leading to 5-coordinate CO-heme, but the detailed mechanism remains unresolved. In this study, we examined the mechanism under the condition including BAY 41-2272, 2'-deoxy-3'-GMP and foscarnet. The addition of these effectors caused the original 6-coordinate CO-heme to convert to an end product that was an equimolar mixture of a 5- and a new 6-coordinate CO-heme, as assessed by IR spectral measurements. The two types of CO-hemes in the end product were further confirmed by CO dissociation kinetics. Stopped-flow measurements under the condition indicated that the ferrous sGC bound CO as two reversible steps, where the primary step was assigned to the full conversion of the ferrous enzyme to the 6-coordinate CO-heme, and subsequently followed by the slower second step leading a partial conversion of the 6-coordinate CO-heme to the 5-coordinate CO-heme. The observed rates for both steps linearly depended on CO concentrations. The unexpected CO dependence of the rates in the second step supports a multistep mechanism, in which the 5-coordinate CO-heme is led by CO release from a putative bis-carbonyl intermediate that is likely provided by the binding of a second CO to the 6-coordinate CO-heme. This mechanism provides a new aspect on the activation of sGC by CO.

Irrigation port hydration in phacoemulsification surgery.

BACKGROUND: In most cases, hydration is performed by water injection into the stromal tissue with a needle. The technique is simple, however it is sometimes troublesome. PURPOSE: We describe a simple technique for hydrating the corneal stroma in cataract surgery using an irrigation port. PATIENTS AND METHODS: The technique began by pushing the irrigation port against the corneal stroma for a few seconds during phacoemulsification, which generated edema in the corneal incision that subsequently prevented leakage. This procedure is called the hydration using irrigation port (HYUIP) technique. A total of 60 eyes were randomized and placed in two groups, 30 eyes underwent surgeries using the HYUIP technique (HYUIP group) and 30 eyes underwent surgeries without the HYUIP technique (control). The three points evaluated during each surgery included 1) the occurrence of anterior chamber collapse during the pulling out of the I/A tip after inserting the intraocular lens, 2) the need for conventional hydration, and 3) watertight completion at the end stage of surgery. RESULTS: The anterior chamber collapse and the need for conventional hydration were significantly smaller in the HYUIP group compared to the control group. Regarding the self-sealing completion, no significant difference was observed between the two groups. CONCLUSION: The HYUIP technique is an effective method for creating self-sealing wound. In addition, this technique helps to prevent anterior chamber collapse.

The effect of the leukotriene antagonist pranlukast on pediatric acute otitis media.

OBJECTIVE: Conventional treatment for acute otitis media mainly targets bacteria with antibiotics, neglecting to control for mediators of inflammation. Mediators of inflammation, such as leukotrienes, have been identified in patients with acute otitis media (AOM) or subsequent secretory otitis media (SOM). They can cause functional eustachian tube dysfunction or increase mucous in the middle ear, causing persistent SOM following AOM. The objective of the present study was to evaluate whether or not administration of pranlukast, a widely used leukotriene C4, D4, and E4 antagonist, together with antibiotics could inhibit the progression to SOM. METHODS: Children with AOM, who were from two to 12 years old, were randomly divided into two groups as follows: a control group in which 50 patients received antibiotic-based conventional treatment according to guidelines for treating AOM proposed by the Japan Otological Society (version 2006); and a pranlukast group, in which 52 patients were administered pranlukast for up to 28 days as well as given conventional treatment. Cases were regarded as persistent SOM when a tympanogram was type B or C2 four weeks after treatment was initiated. RESULTS: Two patients in the pranlukast group and 3 patients in the control group were excluded because they relapsed AOM within 28 days after initial treatment. Therefore, the analysis included 50 and 47 subjects in the pranlukast and control groups, respectively. The percentage of patients diagnosed with persistent SOM (22.0%) was significantly smaller in the pranlukast group compared with the control group (44.7%) (p = 0.018, chi-squared test). CONCLUSION: The results indicate that combined treatment of AOM with antibiotics and a leukotriene antagonist to control inflammation is useful for preventing progression to persistent SOM.

Pressure adaptation of 3-isopropylmalate dehydrogenase from an extremely piezophilic bacterium is attributed to a single amino acid substitution.

3-Isopropylmalate dehydrogenase (IPMDH) from the extreme piezophile Shewanella benthica (SbIPMDH) is more pressure-tolerant than that from the atmospheric pressure-adapted Shewanella oneidensis (SoIPMDH). To understand the molecular mechanisms of this pressure tolerance, we analyzed mutated enzymes. The results indicate that only a single mutation at position 266, corresponding to Ala (SbIPMDH) and Ser (SoIPMDH), essentially affects activity under higher-pressure conditions. Structural analyses of SoIPMDH suggests that penetration of three water molecules into the cleft around Ser266 under high-pressure conditions could reduce the activity of the wild-type enzyme; however, no water molecule is observed in the Ala266 mutant.

A Technique for Preoperative Identification of the Facial Nerve Mandibular Branch Using a Nerve Stimulator.

We established the method of preoperative identification to facial nerve marginal mandibular branch (FNMB) identification using a nerve stimulator with bipolar probe for upper-neck surgery. The bipolar electrode is placed on the region while patients were awake; the patient should be in the same position and posture as during the surgery, with the neck skin stretched. A nerve course is confirmed by observing the movement of the lower lip. In this study, 5 upper-neck surgeries were conducted. Preoperative analysis revealed that 4 of the 5 cases had 2 branches of FNMB, and 1 with 3 branches. All FNMB immediately confirmed preoperatively were identified during surgery. We performed this method in much surgery including the surgery of the upper neck. It was easy to identify the facial nerve by this method and came to be able to do it precisely, and an operative time was shortened. We concluded that the preoperative FNMB identification using a nerve stimulator is most useful and benefit for upper-neck surgery patients and lead to avoid lower lip paralysis.

Pressure effects on the chimeric 3-isopropylmalate dehydrogenases of the deep-sea piezophilic Shewanella benthica and the atmospheric pressure-adapted Shewanella oneidensis.

The chimeric 3-isopropylmalate dehydrogenase enzymes were constructed from the deep-sea piezophilic Shewanella benthica and the shallow water Shewanella oneidensis genes. The properties of the enzymatic activities under pressure conditions indicated that the central region, which contained the active center and the dimer forming domains, was shown to be the most important region for pressure tolerance in the deep-sea enzyme.

Math1, retinoic acid, and TNF-α synergistically promote the differentiation of mucous cells in mouse middle ear epithelial cells in vitro.

BACKGROUND: A key issue in otitis media (OM) is mucous cell metaplasia in the middle ear mucosa, a condition for hyperproduction of mucus in the middle ear mucosa and development of chronic OM. However, little is known about the driving force for the differentiation of mucous cells in OM. METHODS: Mouse middle ear epithelial cells (mMEECs) were used in this study to test whether Math1, a critical transcription factor for the development of mucous cells in the intestine, synergizes with inflammatory cytokines (tumor necrosis factor-α (TNF-α)) and other epithelial differentiation factors (retinoid acid (RA)) to induce the differentiation of mMEECs into mucus-like cells in vitro. Simultaneously, Math1 was transduced into the middle ear mucosa in order to observe whether it induces mucous cell hyperplasia in vivo. RESULTS: Math1 significantly increased the mucus cell numbers in the middle ear mucosa of mice. Math1, in the presence of TNF-α and epithelial differentiation factor RA, synergistically promoted the differentiation of mMEECs into mucus-like cells through upregulation of mucins and their chaperones: trefoil factors in vitro. RA treatment for 12 h activated Math1, although RA alone had very limited effects on mucus-like cell differentiation. CONCLUSION: Math1 plays a critical role in the pathogenesis of OM by induction of mucous cell differentiation in the presence of TNF-α and RA.

Regulation of the angiogenesis of acquired middle ear cholesteatomas by inhibitor of DNA binding transcription factor.

IMPORTANCE: The aggressive growth of cholesteatoma in the middle ear involves the angiogenesis of the cholesteatomal perimatrix. However, which transcription factor is involved in this process remains unclear. OBJECTIVE: To identify a transcription factor that supports the aggressive growth of cholesteatoma by controlling the angiogenesis of cholesteatoma in the middle ear milieu. DESIGN: We used clinical specimens for the profiling of angiogenic factors and their regulatory transcription factors in cholesteatoma. Human skin keratinocytes and endothelial cells were used for evaluation of the effects of candidate transcription factor on the angiogenic factor regulation and endothelial cell proliferation. SETTING: University departments of otolaryngology-head and neck surgery. PARTICIPANTS: Eight clinical cholesteatomal and 8 control specimens were used for cellular and molecular biologic evaluation. An additional 8 cholesteatomal and 8 aural skin specimens were used for microarray studies. MAIN OUTCOME MEASURES: The expression of vascular endothelial growth factor, interleukin 8, and cyclooxygenase 2 as measured by means of immunohistochemistry and molecular biologic methods. RESULTS: Human aural cholesteatomal specimens were rich in the expression of angiogenic factors such as vascular endothelial growth factor in the cholesteatomal matrix and perimatrix, accompanied by the transcription factor inhibitor of DNA binding (Id1). We found Id1 to be an essential regulator of vascular endothelial growth factor. In addition, potent angiogenic factors, including interleukin 8 and cyclooxygenase 2, were regulated by Id1 via different molecular mechanisms. CONCLUSIONS AND RELEVANCE: The transcription factor Id1 controls the angiogenesis of cholesteatoma through the regulation of vascular endothelial growth factor, interleukin 8, and cyclooxygenase 2, which are responsible for the angiogenesis of cholesteatoma. Id1 may serve as a good target for the treatment of cholesteatomal progression in the middle ear milieu.

Optimal duration of macrolide treatment for chronic sinusitis after endoscopic sinus surgery.

OBJECTIVE: The objective is to determine the appropriate duration of postoperative macrolide therapy for chronic rhinosinusitis to obtain a favourable outcome with endoscopic sinus surgery (ESS). METHODS: The effectiveness of postoperative macrolide treatment was examined in patients with chronic rhinosinusitis who underwent ESS, by comparing 3-month (44 patients) and 6-month administration (66 patients) of clarithromycin (CAM) (200mg/day). Evaluation was made based on subjective symptoms and endoscopic findings at 3, 6 and 12 months after surgery. RESULTS: Seventeen (3-month CAM group) and 22 (6-month CAM group) subjects were able to be followed up to 12 months after surgery. No difference in effectiveness was observed between the groups until 6 months after surgery, but the 6-month treatment group showed significantly higher disappearance rates and significantly lower visual analogue scale (VAS) scores in the subjective symptoms of rhinorrhea and postnasal drip at 12 months after surgery. The positive finding rate of postnasal drip by endoscopic examination was also significantly lower in the 6-month treatment group at 12 months after surgery. These changes over time indicated gradual deterioration after discontinuation of CAM treatment in the 3-month treatment group, whereas a small improvement was observed after discontinuation in the 6-month treatment group. CONCLUSION: The results indicate that chronic sinusitis patients with rhinorrhea or postnasal drip should be treated with macrolides for 6 months after surgery in order to improve the long-term outcome of endoscopic sinus surgery.

Id2 regulates the proliferation of squamous cell carcinoma in vitro via the NF-κB/Cyclin D1 pathway.

Squamous cell carcinoma(SCC) is a significant cause of cancer morbidity and mortality worldwide, with an incidence of up to 166 cases per 100 000 population. It arises in the skin, upper aerodigestive tract, lung, and cervix and affects more than 200 000 Americans each year. We report here that a microarray experiment comparing 41 SCC and 13 normal tissue specimens showed that Id2, a gene that controls the cell cycle, was significantly up-regulated in SCC. Enforced expression of Id2 in vitro stimulated the proliferation of SCC cells and up-regulated the transcription of nuclear factor kappa B (NF-κB) and cyclin D1. Enhancement of the NF-κB activity with p65 significantly increased the cell proliferation and the transcription of cyclin D1, whereas inhibition of the NF-κB activity with I kappa B alpha mutant (IκBαM) and pyrroline dithiocarbamate (PDTC) abrogated cell proliferation and transcription of cyclin D1. Furthermore, a mutated NF-κB binding site in the cyclin D1 promoter fully abrogated the Id2-induced transcription of cyclin D1. Taken together, these data indicate that Id2 induces SCC tumor growth and proliferation through the NF-κB/cyclin D1 pathway.

The role of atoh1 in mucous cell metaplasia.

A key issue in otitis media is mucous cell metaplasia which is responsible for mucous hypersecretion and persistence of the disease. However, little is known about the molecular mechanisms of mucous cell metaplasia in otitis media. Numerous studies of intestinal epithelial homeostasis have shown that Atonal homolog 1 (Atoh1), a basic helix-loop-helix (bHLH) transcription factor, is essential for the intestinal goblet cell differentiation. On the other hand, SAM-pointed domain-containing Ets transcription factor (SPDEF), a member of the "Ets" transcription factor family, has been reported to trigger the mucous cell metaplasia of pulmonary infectious diseases or athsma. Recent studies have demonstrated the relation of these factors, that is, Spdef functions downstream of Atoh1. We could take the adventages of these findings for the study of otitis media because both middle ear and pulmonary epithelia belong to the same respiratory tract. Atoh1 and SPDEF could be the therapeutic targets for otitis media associated with mucous cell metaplasia which is frequently considered "intractable" in the clinical settings.

Impaired olfactory function in mice with allergic rhinitis.

OBJECTIVE: It has been reported that olfactory function is impaired in patients with allergic rhinitis. However, the mechanism of olfactory dysfunction in allergic rhinitis remains poorly understood. Because of difficulties in obtaining and analyzing human olfactory mucosa due to both technical and ethical issues, an animal model needs to be established to clarify the mechanism of olfactory dysfunction in allergic rhinitis. The purpose of this study was to study olfactory function and changes in olfactory mucosa using allergic rhinitis mice. METHODS: A model of allergic rhinitis mice with olfactory dysfunction was developed by sensitizing with ovalbumin (OVA), and intranasally challenging with the same allergen. Olfactory function of mice with or without allergic rhinitis was assessed by odor detection ability test with cycloheximide and local field potential (LFP) with 1-octanal. We also evaluated histological changes in the olfactory mucosa of allergic rhinitis mice by both light and electron microscopy. RESULTS: Both of odor detection ability test and LFP showed that olfactory function was impaired in mice with allergic rhinitis, but not in mice without allergic rhinitis. Histopathological findings showed prominent infiltration of eosinophils, plasma cells, neutrophils, mast cells, and macrophages in lamina propria of olfactory mucosa of mice with allergic rhinitis, although infiltration of these cells was not seen in control mice. Allergic rhinitis also increased the number and size of glands in olfactory mucosa, suggesting an elevated amount of mucin in olfactory mucosa. CONCLUSION: This study showed for the first time that mice with allergic rhinitis have impaired olfactory function, increased size and number of olfactory glands, and infiltration of eosinophils, neutrophils, mast cells, plasma cells, and macrophages in the olfactory mucosa. This suggests that allergic reactions are seen in olfactory mucosa of mice with allergic rhinitis, and that greater olfactory gland activity is associated with olfactory dysfunction. Also, this mouse model could provide an expedient system for analyzing mechanisms of olfactory dysfunction.

Sonic hedgehog (SHH) promotes the differentiation of mouse cochlear neural progenitors via the Math1-Brn3.1 signaling pathway in vitro.

Sonic hedgehog (SHH) is essential for the development of the cochlear duct that harbors the organ of Corti. However, little is known about the molecular signaling pathway through which SHH promotes the development of the organ of Corti, especially cochlear sensory epithelial cells. In this study, we demonstrated that SHH contributes to the differentiation of cochlear neural progenitors (CNPs), which are derived from the postnatal day 1 organ of Corti in mice. Addition of SHH to CNPs increased the formation of epithelial cell islands, simultaneously activated the expression of Math1 that is a transcription factor for the initial differentiation of auditory hair cells. The increased expression of Math1 then regulated the promoter activity of Brn3.1, another transcription factor that controls the further differentiation and survival of auditory hair cells. Taken together, our data suggest that SHH plays an important role in the promotion of auditory hair cell differentiation via the Math1-Brn3.1 signaling pathway.

Directed differentiation of mouse cochlear neural progenitors in vitro.

Multipotent cochlear neural progenitors (CNPs) in the organ of Corti hold the promise for cell replacement in degenerative hearing disorders. However, not much is known about the CNPs and the specific conditions for their differentiation. Here we isolate the CNPs from the postnatal day 1 organ of Corti in mice and demonstrate their capability to self-renew and to differentiate into hair cell-like and neuronal cell-like phenotypes under the guidance of sonic hedgehog (SHH), epidermal growth factor (EGF), retinoic acid (RA), and brain-derived neurotrophic factor (BDNF), herein termed SERB (abbreviation of SHH, EGF, RA, and BDNF) in an asymmetric or symmetric manner from clonal isolates. Differentiation of CNPs into hair cells by SERB was dependent on the ERK signaling pathway, whereas the differentiation of CNPs into neurons by SERB was not. This work develops a new in vitro methodology for the maintenance and self-regeneration of CNPs for future design of regenerative strategies for hearing disorders.

Identification of Id1 in acquired middle ear cholesteatoma.

OBJECTIVES: To determine (1) the relationship between chronic inflammatory changes in the ossicular chain area (OCA) and the formation of cholesteatoma and (2) the correlates between aberrant gene expression and abnormal proliferation of cholesteatoma. METHODS: Two hundred sixty-four ears with chronic otitis media that had undergone ear surgery were included in this study for statistical analysis of the relationship between abnormalities in the OCA and cholesteatoma. Fourteen middle ear cholesteatoma specimens were collected for immunohistochemical analysis of candidate molecules involved in the abnormal proliferation of keratinocytes. A cell model was used for verification of candidate molecule involvement. RESULTS: The formation of cholesteatoma was accompanied by chronic inflammatory changes in the OCA, including granulated tissue, adhesion, and stagnating effusion. The inhibitor of the DNA-binding (Id1) gene, which is involved in controlling cell cycle progression, was abundantly expressed in cholesteatoma epithelium. In vitro studies indicate that Id1 regulated the expression of nuclear factor kappaB, cyclin D1, proliferating cell nuclear antigen, and cell cycle progression of keratinocytes, CONCLUSIONS: Chronic inflammation in the OCA is closely related to the formation of cholesteatoma. The Id1/nuclear factor kappaB/cyclin D1/proliferating cell nuclear antigen signaling pathway is involved in the abnormal proliferation of keratinocytes in acquired cholesteatoma.

Cochlear stem cells/progenitors and degenerative hearing disorders.

Hearing loss (deafness) affects approximately 250 million people globally. The major cause of deafness is loss of hair cells and spiral ganglion neurons due to aging, antibiotic use, noise exposure, and genetic defects. At the present time, there is no effective method for restoration of hearing biologically. Cochlear stem cells/progenitors (CSCs), quiescent in the organ of Corti, are excellent candidates for restoration of cell types in the organ of Corti biologically. However, little is known about the biology of CSCs and developmental cues for CSCs to differentiate into hair cells and neurons at the present time. In this article, we briefly reviewed the isolation of CSCs from the postnatal organ of Corti in mice and their capability to differentiate into hair cells and neurons in vitro under the guidance of a group of growth factors: sonic hedgehog (SHH), epidermal growth factor (EGF), retinoic acid (RA), and brain-derived neurotrophic factor (BDNF), herein termed SERB. The identification of CSCs and their differentiation signals is potentially of clinical importance.

Expression of Syk is associated with nasal polyp in patients with allergic rhinitis.

OBJECTIVE: Numerous signalings are involved in allergic inflammation. The non-receptor protein tyrosine kinase, Syk, is widely expressed in immune-potentiated cells and plays critical roles in initiating signal transduction in response to the activation of cytokine, chemokine and other types of receptors. It has been hypothesized that Syk expression in allergic nasal mucosa and polyps with allergy is different from non-allergic mucosa, and that changes in Syk expression contribute to the activation of allergic reactions. METHODS: We examined whether the expression of Syk is found in allergic nasal mucosa and polyps. We investigated the expression of Syk in 46 nasal mucosa and polyps (14 samples from patients with allergic rhinitis and 32 samples with non-allergic chronic sinusitis) using an immunohistochemical technique. RESULTS: Allergic polyps had more Syk positive cells than non-allergic polyps. Syk positive cells were determined to mainly be eosinophils. There was no difference in Syk expression in the lamina propria and nasal gland between allergic mucosa and non-allergic mucosa. CONCLUSION: Eosinophils in allergic polyps receive an intracellular signal, although the signal is not able to determine the function in the present state. Syk appears to be a promising target molecule for anti-allergic inflammation in allergic rhinitis.