Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P15088 (mast cell)
 14,925 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mast cell--an important component of connective tissue--carries in its cytoplasmic granules various biologically active substances, such as heparin, histamine, and a broad spectrum of enzymes. This cell type plays a prominent role in inflammatory and allergic conditions. In the middle ear, the mast cells are mainly localized in the pars flaccida of the tympanic membrane and beneath the tracts of secretory and ciliated cells in the middle ear mucosa. Degranulation of the mast cells by the histamine liberator compound 48/80 causes histamine-rich effusion material to accumulate in the middle ear. Plugging of the eustachian tube and/or tympanic isthmus will bring about a similar accumulation. It would thus seem that mast cells in some way participate in the production of middle ear effusion, probably via their potent mediators.
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PMID:Mast cells and middle ear effusion. 240 31

The inhibitory effects of ketotifen, a histamine H1-receptor antagonist and mast cell stabilizer, were examined on a non-IgE experimental model of middle ear effusion. Thirty rats were divided into three groups. Group A (n = 9) was subjected to mechanical stimulation of the external auditory canal (EAC); group B (n = 11) was pre-treated with intraperitoneal administration of 0.2 mg ketotifen, 90 min before mechanical stimulation of the EAC; and group C (n = 10), the control group, was neither exposed to mechanical stimulation nor given ketotifen. Thirty minutes after completion of the experiment, the eardrums were inspected, histamine levels were determined by a fluorometric assay, and the pars flaccida underwent histological assessment. An attic effusion was observed in group A; a similar phenomenon but to a lesser extent was also seen in group B. Statistical analysis confirmed that the mean histamine concentration of the rinsing fluid obtained from group A was significantly higher than that of group C (p = 0.004) or group B (p = 0.008). No significant difference was found between the mean histamine concentration of groups C and group B (p = 0.311). Histological assessment revealed that the thickness of the pars flaccida of group A was considerably greater than that of groups C and B and was characterized by marked edema. Furthermore, the pars flaccida mast cell population was significantly depleted compared with groups C and B. The data indicate that mechanical stimulation of the EAC triggered the pars flaccida mast cells to degranulate in a non-mediated IgE fashion and that histamine is implicated in most of these histological changes. It is concluded that administration of ketotifen before mechanical stimulation of the EAC had a stabilizing effect and abolished mast cell degranulation, therefore, may be considered as a potential therapeutic agent for the treatment of middle ear disease in the pediatric population.
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PMID:Ketotifen induced inhibition of histamine release in a non-IgE model of middle ear effusion. 1642 54

Eosinophilic otitis media (EOM) is an intractable otitis media characterized by the presence of a highly viscous yellow effusion containing eosinophils. It mainly occurs in patients with bronchial asthma and is resistant to conventional treatments for otitis media. Here we discuss the role of IgE in the pathogenesis of EOM. In middle ear effusion, a significantly higher IgE level was detected in EOM patients than in control patients with common otitis media with effusion. This IgE level was significantly higher (about 10 fold) than the serum IgE level. In addition, many IgE-immunopositive cells were found in the middle ear mucosa. The IgE staining was mainly observed on mast cell surfaces, but also partially in the cytoplasm of cells that appeared to be plasma cells. These results suggested that IgE is produced locally in the middle ear mucosa. The existence of high-level IgE may exacerbate eosinophilic inflammation in the middle ear. One of the most distinct characteristics of EOM is the high incidence of sensory hearing loss independent of age. High-tone hearing loss is more frequently found and more severe in EOM patients than in control patients with common chronic otitis media. The concentration of IgE in middle ear effusion significantly and positively correlated with bone conduction hearing levels at 2 kHz and 4 kHz in EOM patients. Overproduction of IgE locally in the middle ear may be related to the pathological condition of EOM and eventually cause inner ear damage.
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PMID:Role of IgE in eosinophilic otitis media. 2065 63