Risk Factors and Prognostic Factors of Hearing Impairment in Neonatal Intensive Care Unit-Treated Infants.

BACKGROUND: Infants admitted to the neonatal intensive care unit (NICU) have a higher incidence of congenital hearing loss compared with the healthy newborn population. OBJECTIVES: To clarify the relationship between risk factors for hearing impairment in NICU-treated infants and deterioration of the auditory brainstem response (ABR) threshold during childhood. METHOD: We screened 1,071 high-risk infants admitted to the NICU for hearing impairment. One-hundred forty-eight infants exhibited an abnormal ABR threshold of ≥40 dB nHL. We analyzed the correlation of change in ABR threshold with risk factors for future hearing impairment. RESULTS: Among infants treated in the NICU, 148 (13.8%) exhibited an ABR threshold of ≥40 dB nHL; 107 of these 148 (72.3%) showed hearing change in the process (102 showed improvement to normal hearing level, whereas 5 showed further deterioration). Our analysis showed that the factors contributing to the elevation of ABR threshold were oxygen administration and chromosomal aberrations. CONCLUSIONS: Factors related to the elevation of ABR threshold were oxygen administration and the presence of chromosomal aberrations. Awareness of risk factors that are more likely to cause hearing loss in infants may aid in follow-up treatment of these children.

[A Case of Infantile Cervical Ectopic Thymus].

We report herein on a case of ectopic cervical thymus in a 5-year-old boy and the literature is reviewed. Swelling of the right neck was seen in the patient in his newborn period and it was diagnosed as cystic disease of the neck in a previous hospital at 4 months of age. Ultrasonography (US) and MRI revealed a cervical tumor consisting of a solid component in our hospital, and histopathologic examination showed no evidence of malignancy. The lesion revealed almost no change in size but showed a mosaic pattern on US, whereon the parents agreed to the removal of the tumor. Intraoperatively, the tumor could be easily dissected from the surrounding tissue and resected. The pathological diagnosis was normal thymic tissue. The postoperative course was uneventful and no complication or immunological disorders were seen. A cervical ectopic thymus is a congenital lesion that results from abnormal thymic migration during embryogenesis. Most patients are asymptomatic and the condition is found incidentally. Preoperative diagnosis of cervical ectopic thymus in children is rarely made, so surgical treatment is the definitive means of pathological diagnosis. This disease should be listed in the differential diagnosis for neck masses in children, and should be suspected when the mosaic pattern is detected in the lesion on US.

Prevention of lung injury by Muc1 mucin in a mouse model of repetitive Pseudomonas aeruginosa infection.

OBJECTIVE AND DESIGN: To determine whether repetitive airway Pseudomonas aeruginosa (Pa) infection results in lung inflammation and injury and, if so, whether these responses are affected by Muc1 mucin. Muc1 wild type (WT) and knockout (KO) mice were compared for body weights, lung inflammatory responses, and airspace enlargement using a chronic lung infection model system. MATERIALS: Mice were treated intranasally with Pa (10(7) CFU) on days 0, 4, 7 and 10. On day 14, body weights, inflammatory cell numbers in bronchoalveolar lavage fluid (BALF), and airspace enlargement were measured. Differences in inflammatory responses between groups were statistically analyzed by the Student's t test and ANOVA. RESULTS: Muc1 WT mice exhibited mild degrees of both inflammation and airspace enlargement following repetitive airway Pa infection. However, Muc1 KO mice exhibited significantly decreased body weights, greater macrophage numbers in the BALF, and increased airspace enlargement compared with Muc1 WT mice. CONCLUSIONS: This is the first report demonstrating that Muc1 deficiency can lead to lung injury during chronic Pa infection in mice. These results suggest that MUC1 may play a crucial role in the resolution of inflammation during chronic respiratory infections and that MUC1 dysfunction likely contributes to the pathogenesis of chronic inflammatory respiratory disease.

Antiinflammatory role of MUC1 mucin during infection with nontypeable Haemophilus influenzae.

MUC1 (or Muc1 in nonhuman species) is a membrane-tethered mucin expressed on the apical surface of mucosal epithelia (including those of the airways) that suppresses Toll-like receptor (TLR) signaling. We sought to determine whether the anti-inflammatory effect of MUC1 is operative during infection with nontypeable Haemophilus influenzae (NTHi), and if so, which TLR pathway was affected. Our results showed that: (1) a lysate of NTHi increased the early release of IL-8 and later production of MUC1 protein by A549 cells in dose-dependent and time-dependent manners, compared with vehicle control; (2) both effects were attenuated after transfection of the cells with a TLR2-targeting small interfering (si) RNA, compared with a control siRNA; (3) the NTHi-induced release of IL-8 was suppressed by an overexpression of MUC1, and was enhanced by the knockdown of MUC1; (4) the TNF-α released after treatment with NTHi was sufficient to up-regulate MUC1, which was completely inhibited by pretreatment with a soluble TNF-α receptor; and (5) primary murine tracheal surface epithelial (MTSE) cells from Muc1 knockout mice exhibited an increased in vitro production of NTHi-stimulated keratinocyte chemoattractant compared with MTSE cells from Muc1-expressing animals. These results suggest a hypothetical feedback loop model whereby NTHi activates TLRs (mainly TLR2) in airway epithelial cells, leading to the increased production of TNF-α and IL-8, which subsequently up-regulate the expression of MUC1, resulting in suppressed TLR signaling and decreased production of IL-8. This report is the first, to the best of our knowledge, demonstrating that the inflammatory response in airway epithelial cells during infection with NTHi is controlled by MUC1 mucin, mainly through the suppression of TLR2 signaling.

Membrane-tethered MUC1 mucin is phosphorylated by epidermal growth factor receptor in airway epithelial cells and associates with TLR5 to inhibit recruitment of MyD88.

MUC1 is a membrane-tethered mucin glycoprotein expressed on the apical surface of mucosal epithelial cells. Previous in vivo and in vitro studies established that MUC1 counterregulates airway inflammation by suppressing TLR signaling. In this article, we elucidate the mechanism by which MUC1 inhibits TLR5 signaling. Overexpression of MUC1 in HEK293 cells dramatically reduced Pseudomonas aeruginosa-stimulated IL-8 expression and decreased the activation of NF-κB and MAPK compared with cells not expressing MUC1. However, overexpression of MUC1 in HEK293 cells did not affect NF-κB or MAPK activation in response to TNF-α. Overexpression of MyD88 abrogated the ability of MUC1 to inhibit NF-κB activation, and MUC1 overexpression inhibited flagellin-induced association of TLR5/MyD88 compared with controls. The MUC1 cytoplasmic tail associated with TLR5 in all cells tested, including HEK293T cells, human lung adenocarcinoma cell line A549 cells, and human and mouse primary airway epithelial cells. Activation of epidermal growth factor receptor tyrosine kinase with TGF-α induced phosphorylation of the MUC1 cytoplasmic tail at the Y46EKV sequence and increased association of MUC1/TLR5. Finally, in vivo experiments demonstrated increased immunofluorescence colocalization of Muc1/TLR5 and Muc1/phosphotyrosine staining patterns in mouse airway epithelium and increased Muc1 tyrosine phosphorylation in mouse lung homogenates following P. aeruginosa infection. In conclusion, epidermal growth factor receptor tyrosine phosphorylates MUC1, leading to an increase in its association with TLR5, thereby competitively and reversibly inhibiting recruitment of MyD88 to TLR5 and downstream signaling events. This unique ability of MUC1 to control TLR5 signaling suggests its potential role in the pathogenesis of chronic inflammatory lung diseases.

Role of interleukin-15 in the development of mouse olfactory nerve.

Interleukin (IL)-15 interacts with components of the IL-2 receptor (R) and exhibits T cell-stimulating activity similar to that of IL-2. In addition, IL-15 is widely expressed in many cell types and tissues, including the central nervous system. We provide evidence of a novel role of IL-15 in olfactory neurogenesis. Both IL-15 and IL-15R alpha were expressed in neuronal precursor cells of the developing olfactory epithelium in mice. Adult IL-15R alpha knockout mice had fewer mature olfactory neurons and proliferating cells than wild-type. Our results suggest that IL-15 plays an important role in regulating cell proliferation in olfactory neurogenesis.

Development of olfactory epithelium in the human fetus: scanning electron microscopic observations.

AIMS: Human olfactory epithelium becomes functional at birth, but prenatal development remains unclear. In the present study, we aimed to clarify the development of human olfactory epithelium using scanning electron microscopy (SEM). METHODS: The development of human olfactory epithelium was observed in 24 externally normal fetuses, which were formalin-fixed and long-preserved, with a crown-rump length (CRL) of 102-336 mm (gestational week 14-38). The olfactory mucosa in the superior wall of the nasal septum near the choana were dissected and observed under SEM. We examined the number of olfactory vesicles per unit area, diameter of olfactory vesicles, and number and length of cilia on olfactory vesicles. RESULTS: At circa (ca) CRL 100 mm (ca 14 weeks), olfactory epithelium displayed several olfactory vesicles with 1-2 short cilia per unit area. At ca CRL 150 mm (ca 18 weeks), olfactory vesicles were present in small clusters, and cilia were longer. At CRL lager than 225 mm (ca 26 weeks), olfactory vesicles became located separately from each other, while length and number of cilia per olfactory vesicle were further increased. CONCLUSION: The present findings suggest that fetal olfactory epithelium becomes morphologically almost the same as that in adults in late gestation, much later than previously thought.

[Caloric test in low-tone sensorineural hearing loss].

Acute low-tone sensorineural hearing loss (ALHL) is generally has a relatively good prognosis. We have often found in long-term following-up, however, that ALHL relapses, recurs or develops into Meniere's disease. Diagnostic criteria of the Acute Altitude Deafness Research Group of the Ministry of Health, Labor, and Welfare of Japan, define ALHL as low-tone-disorder sensorineural hearing loss without vertigo in which cochlear symptoms -ear fullness, tinnitus, and deafness- develop suddenly. Over the last five years, we have treated 31 cases of ALHL, in about half of which neurotological examination showed potential peripheral vestibular dysfunction on testing positional nystagmus (a) with closed eyes and (b) in a dark room with open eyes, and by finding laterality in the peripheral labyrinth system on caloric test. These cases show high canal paresis -a maximum slow- phase eye velocity of caloric nystagmus exceeding 60%. These results, taken together, suggest that derangement extends to the peripheral labyrinth system in patients with ALHL.

The management of possible fishbone ingestion.

OBJECTIVE: We assessed the usefulness of computed tomography (CT) in cases of suspected impaction of fish bones in the esophagus. The findings of this study were also compared with those of studies in which surgery was used to remove or confirm the presence of fish bones. We accordingly propose a management protocol to ensure optimum outcome for patients with a history of fish bone ingestion. METHODS: X-ray and CT imaging were performed in 76 patients in whom esophageal impaction of fish bones was suspected. RESULTS: Plain X-ray revealed impacted fish bones in 17 patients (22%), soft-tissue swelling but no evidence of foreign body in 5 (7%), and no abnormal findings in 54 (71%). These findings were apparent on CT scans in 31 (41%), 8 (10%), and 37 (49%), respectively. Of the 31 patients in whom CT revealed a fishbone, 17 (55%) also exhibited X-ray evidence of foreign body. Of the remainder, X-ray revealed only soft-tissue swelling in 3 (10%), and was unremarkable in 11 (35%). Among the 5 patients in whom X-ray demonstrated only soft-tissue swelling, CT was positive for foreign body in 3 (60%). Of the 54 patients in whom X-ray appearances were normal, CT revealed foreign bodies in 11 (20%) and other abnormalities in 6 (11%). CONCLUSION: In the present study, sensitivity and specificity of plain X-ray was 54.8% (17 of 31) and 100% (45 of 45), respectively. However, for CT, both sensitivity and specificity were 100%. CT was determined to be very useful in the diagnosis of impacted fish bones in the esophagus.

[Clinical effect of bipolar radiofrequency thermotherapy on allergic rhinitis].

The clinical effect of bipolar radiofrequency thermotherapy on allergic rhinitis was evaluated. A bipolar radiofrequency system (CelonLab ENT) was used to treat 16 patients suffering from allergic rhinitis between February 2003 and August 2003. The thermotherapy was performed under local anesthesia at the otolaryngology outpatient clinic of St. Marianna University Toyoko Hospital. Data were collected by questionnaire and rhinomanometry preoperatively and 2 months postoperatively. The mean visual analogue scale (VAS) score for intraoperative pain was 31 mm (range, 0-100), and nearly all the patients felt no or a subtle pain during the thermotherapy. Postoperative pain was also well tolerated, with nearly all the patients not requiring analgesic drugs. Postoperative bleeding was minor, and none of the patients required additional treatment for bleeding. Nearly all the patients reported an improvement in their nasal patency, rhinorrhea, headaches, and sleeping. Statistically significant improvements were observed for all the measured VAS scores: nasal patency, rhinorrhea, headache, and olfactory function. Nasal resistance, as measured by anterior rhinomanometry, significantly improved after treatment. The effect of decongestion was also measured using anterior rhinomanometry. The ratio of nasal resistance before and after decongestion was significantly higher after thermotherapy, suggesting that nasal decongestion had a smaller effect on nasal patency after treatment. The current results suggest that the CelonLab ENT device is an effective and safe treatment for allergic rhinitis.