Exploring definitions and predictors of response to biologics for severe asthma

BACKGROUND

Biologic effectiveness is often assessed as 'response', a term which eludes consistent definition. Identifying those most likely to respond in real-life has proven challenging.

OBJECTIVE

To explore definitions of biologic responders in adults with severe asthma and investigate patient characteristics associated with biologic response.

METHODS

This was a longitudinal cohort study using data from 21 countries, which shared data with the International Severe Asthma Registry. Changes in 4 asthma outcome domains were assessed in the 1-year period pre- and post-biologic-initiation in patients with predefined level of pre-biologic impairment. Responder cut-offs were: ≥50% reduction in exacerbation rate, ≥50% reduction in long-term oral corticosteroid [LTOCS] daily dose, ≥1 category improvement in asthma control, and ≥100mL improvement in FEV1. Responders were defined using single- and multiple-domains. The association between pre-biologic characteristics and post-biologic-initiation response were examined by multivariable analysis.

RESULTS

2,210 patients were included. Responder rate ranged from 80.7% (n=566/701) for exacerbation-response to 10.6% (n=9/85) for 4-domain-response. Many responders still exhibited significant impairment post-biologic-initiation: 46.7% (n=206/441) of asthma control-responders with uncontrolled asthma pre-biologic still had incompletely-controlled disease post-biologic-initiation. Predictors of response were outcome-dependent. Lung function-responders were more likely to have higher pre-biologic FeNO (OR:1.20 for every 25ppb increase), and shorter asthma duration (OR:0.81, for every 10-year increase in duration). Higher BEC and presence of T2-related comorbidities were positively associated with higher odds of meeting LTOCS-, control- and lung function-responder criteria.

CONCLUSION

Our findings underscore the multi-modal nature of 'response', show that many responders experience residual symptoms post-biologic-initiation, and that predictors of response vary according to outcome assessed.

Exploring Definitions and Predictors of Severe Asthma Clinical Remission Post-Biologic in Adults

RATIONALE

There is no consensus on criteria to include in an asthma remission definition in real-life. Factors associated with achieving remission post-biologic-initiation remain poorly understood.

OBJECTIVES

To quantify the proportion of adults with severe asthma achieving multi-domain-defined remission post-biologic-initiation and identify pre-biologic characteristics associated with achieving remission which may be used to predict it.

METHODS

This was a longitudinal cohort study using data from 23 countries from the International Severe Asthma Registry. Four asthma outcome domains were assessed in the 1-year pre- and post-biologic-initiation. A priori-defined remission cut-offs were: 0 exacerbations/year, no long-term oral corticosteroid (LTOCS), partly/well-controlled asthma, and percent predicted forced expiratory volume in one second ≥80%. Remission was defined using 2 (exacerbations + LTOCS), 3 (+control or +lung function) and 4 of these domains. The association between pre-biologic characteristics and post-biologic remission was assessed by multivariable analysis.

MEASUREMENTS AND MAIN RESULTS

50.2%, 33.5%, 25.8% and 20.3% of patients met criteria for 2, 3 (+control), 3 (+lung function) and 4-domain-remission, respectively. The odds of achieving 4-domain remission decreased by 15% for every additional 10-years asthma duration (odds ratio: 0.85; 95% CI: 0.73, 1.00). The odds of remission increased in those with fewer exacerbations/year, lower LTOCS daily dose, better control and better lung function pre-biologic-initiation.

CONCLUSIONS

One in 5 patients achieved 4-domain remission within 1-year of biologic-initiation. Patients with less severe impairment and shorter asthma duration at initiation had a greater chance of achieving remission post-biologic, indicating that biologic treatment should not be delayed if remission is the goal. This article is open access and distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives License 4.0 (http://creativecommons.org/licenses/by-nc-nd/4.0/).

International severe asthma registry (ISAR): protocol for a global registry

Background

Severe asthma exerts a disproportionately heavy burden on patients and health care. Due to the heterogeneity of the severe asthma population, many patients need to be evaluated to understand the clinical features and outcomes of severe asthma in order to facilitate personalised and targeted care. The International Severe Asthma Registry (ISAR) is a multi-country registry project initiated to aid in this endeavour.

Methods

ISAR is a multi-disciplinary initiative benefitting from the combined experience of the ISAR Steering Committee (ISC; comprising 47 clinicians and researchers across 29 countries, who have a special interest and/or experience in severe asthma management or establishment and maintenance of severe asthma registries) in collaboration with scientists and experts in database management and communication. Patients (≥18 years old) receiving treatment according to the 2018 definitions of the Global Initiative for Asthma (GINA) Step 5 or uncontrolled on GINA Step 4 treatment will be included. Data will be collected on a core set of 95 variables identified using the Delphi method. Participating registries will agree to provide access to and share standardised anonymous patient-level data with ISAR. ISAR is a registered data source on the European Network of Centres for Pharmacoepidemiology and Pharmacovigilance. ISAR’s collaborators include Optimum Patient Care, the Respiratory Effectiveness Group (REG) and AstraZeneca. ISAR is overseen by the ISC, REG, the Anonymised Data Ethics & Protocol Transparency Committee and the ISAR operational committee, ensuring the conduct of ethical, clinically relevant research that brings value to all key stakeholders.

Conclusions

ISAR aims to offer a rich source of real-life data for scientific research to understand and improve disease burden, treatment patterns and patient outcomes in severe asthma. Furthermore, the registry will provide an international platform for research collaboration in respiratory medicine, with the overarching aim of improving primary and secondary care of adults with severe asthma globally.

Occupational exposure and idiopathic pulmonary fibrosis: a multicentre case-control study in Korea

SETTING

Multicentred hospital-based cases and control subjects in Korea.

OBJECTIVE

To evaluate the association between idiopathic pulmonary fibrosis (IPF) and hazardous materials to which people are occupationally exposed.

DESIGN

A multicentre, hospital-based, matched case-control study was performed. The ratio of IPF cases to controls was 1:1 (n = 78 in each group). IPF cases and controls were matched in terms of age group, sex and place of residence. Conditional logistic regression analysis was performed.

RESULTS

In simple logistic regression analysis, exposure to metal dust and any exposure for >1 year in an occupational setting were significantly associated with IPF (metal dust OR 4.00, 95%CI 1.34-11.97; any exposure OR 3.67, 95%CI 1.02-13.14). After adjustment for environmental and military exposures and smoking history, the OR for metal dust exposure was 4.97 (95%CI 1.36-18.17) in multiple logistic regression analysis.

CONCLUSIONS

Metal dust was associated with incident IPF in Seoul and Gyeonggi Provinces in Korea. This information will be used to support a tailored preventive strategy in specific industries or occupations.

Incidence and prevalence of idiopathic interstitial pneumonia and idiopathic pulmonary fibrosis in Korea

SETTING

Although the incidence and prevalence of idiopathic interstitial pneumonia (IIP) and idiopathic pulmonary fibrosis (IPF) have been assessed in Western countries, their epidemiology has not been analysed in Asian countries, including the Republic of Korea.

OBJECTIVE

To estimate the prevalence and incidence of IIP, including IPF, in Korea, using a large, nationwide database.

DESIGN

The Health Insurance Review and Assessment Services claims database, which includes information on every patient with diagnostic codes for IPF and IIP from 2010 to 2013, was reviewed. Age- and sex-specific IPF and IIP prevalence and incidence rates were estimated.

RESULTS

Among Korean males and females, IPF prevalence from 2010 to 2013 was estimated at respectively 39.7 and 24.3 per 100 000 population, while IIP prevalence was estimated at respectively 97.1 and 66.5/100 000. The annual incidence rates among Korean males and females during 2011 and 2012 were respectively 16.4 and 9.7/100 000, for IPF, and respectively 42.3 and 27.5/100 000 for IIP.

CONCLUSIONS

IPF is more prevalent in Korea than previously reported; its prevalence may be similar to or higher than in the United States and in European countries.

Effect of roflumilast on airway remodelling in a murine model of chronic asthma

BACKGROUND

Airway remodelling is associated with irreversible, or partially reversible, airflow obstruction and ultimately unresponsiveness to asthma therapies such as corticosteroids. Roflumilast is a selective phosphodiesterase-4 inhibitor that has an anti-inflammatory effect in chronic obstructive pulmonary disease (COPD).

OBJECTIVE

The objective of this study was to study the effect of roflumilast on airway inflammation and remodelling in a murine model of chronic asthma.

METHODS

BALB/c mice sensitized to ovalbumin (OVA) were chronically exposed to intranasal OVA administration twice a week for additional 3 months. Roflumilast was administered orally during the intranasal OVA challenge. A lung fibroblast cell line was used in the proliferation assay.

RESULTS

Compared with control mice, mice chronically exposed to OVA developed eosinophilic airway inflammation, airway hyper-responsiveness (AHR), and exhibited features of airway remodelling. Administration of roflumilast significantly inhibited airway inflammation and AHR. Roflumilast also significantly decreased goblet cell hyperplasia and pulmonary fibrosis, which are parameters of airway remodelling. The levels of interleukin (IL)-4, IL-5, and IL-13 in the bronchoalveolar lavage (BAL) fluids were significantly lower in the roflumilast group. In vitro, roflumilast significantly inhibited stem cell factor (SCF)-induced cell proliferation of fibroblasts. The SCF concentration and mRNA expression in a murine model also significantly decreased with roflumilast treatment.

CONCLUSIONS

These results suggest that the administration of roflumilast regulates airway inflammation, AHR, and airway remodelling in a model of chronic asthma. The beneficial effects from roflumilast may be related to the SCF/c-kit pathway.

Risk factors for lung function impairment among the general non-smoking Korean population

SETTING

Nationwide general population in South Korea.

OBJECTIVE

Except for tobacco smoking, risk factors for the impairment of lung function have not been widely evaluated. We evaluated the risk factors for lung function impairment among the general non-smoking Korean population.

DESIGN

A total of 8164 non-smokers from the spirometry data set of the Korean National Health and Nutrition Examination Surveys IV and V (2008-2010) were included in the study. After sex stratification, multiple survey logistic regression analyses were performed to estimate the association between potential risk factors and impaired lung function in this nationwide cross-sectional study.

RESULTS

The proportion of non-smokers among the general Korean population with forced expiratory volume in 1 s (FEV1) < 80% of predicted, forced vital capacity (FVC) < 80% of predicted and FEV1/FVC ratio < 0.7 were respectively 46.2%, 50.3% and 30.2%. In multiple survey logistic regression analyses, lung function impairment was associated with tuberculosis (TB) and asthma in female non-smokers and asthma in male non-smokers.

CONCLUSIONS

TB and asthma are risk factors for lung function impairment among Korean non-smokers. To prevent further lung function impairment, a careful control system for these factors should be considered when setting health policy priorities.

Clinical characteristics of patients with tuberculosis-destroyed lung

SETTING

Multicentre study.

OBJECTIVE

To define the clinical characteristics of patients with tuberculosis (TB) destroyed lung due to past TB.

DESIGN

We reviewed patients with TB-destroyed lung between May 2005 and June 2011.

RESULTS

A total of 595 patients from 21 hospitals were enrolled. The mean age was 65.63 ± 0.47 (mean ± standard error); 60.5% were male. The mean number of lobes involved was 2.59 ± 0.05. Pleural thickening was observed in 54.1% of the patients. Mean forced vital capacity (FVC), forced expiratory volume in 1 s (FEV(1)), FEV(1)/FVC, bronchodilator response and number of exacerbations per year were respectively 2.06 ± 0.03 l (61.26% ± 0.79), 1.16 ± 0.02 l (49.05% ± 0.84), 58.03% ± 0.70, 5.70% ± 0.34, and 0.40 ± 0.04. The number of lobes involved was significantly correlated with FVC and FEV(1), and with the number of exacerbations per year. Use of long-acting muscarinic antagonists or long-acting beta-2 agonists plus inhaled corticosteroids resulted in bronchodilatory effects. Multivariable regression analysis showed that age, initial FEV(1) (%) and number of exacerbations during follow-up were independent factors affecting change in FEV(1).

CONCLUSION

Decreased lung function with exacerbation, and progressive decline of FEV(1) were observed in patients with TB-destroyed lung.

Effect of fudosteine on mucin production

Fudosteine is a novel mucoactive agent, although little is known about how fudosteine decreases mucin production. The present study examined the effects of fudosteine on MUC5AC mucin synthesis and cellular signalling. An animal model of lipopolysaccharide (LPS)-induced inflammation and a bronchial epithelial cell line model of tumour necrosis factor (TNF)-alpha-induced inflammation were used. Fudosteine was administered before stimulation with LPS or TNF-alpha. The MUC5AC mucin levels were assayed and the expression of the MUC5AC gene was measured. Western blotting was carried out for the detection of phosphorylated epidermal growth factor receptor (p-EGFR), phosphorylated p38 mitogen-activated protein kinase (p-p38 MAPK) and phosphorylated extracellular signal-related kinase (p-ERK). MUC5AC mucin synthesis and the expression of the MUC5AC gene were increased by LPS in rats or TNF-alpha in NCI-H292 cells; these effects were inhibited by fudosteine treatment. After stimulation with LPS or TNF-alpha, the expression of p-EGFR, p-p38 MAPK and p-ERK were detected. Fudosteine treatment reduced the expression levels of p-p38 MAPK and p-ERK in vivo and of p-ERK in vitro. The present results suggest fudosteine inhibits MUC5AC mucin hypersecretion by reducing MUC5AC gene expression and the effects of fudosteine are associated with the inhibition of extracellular signal-related kinase and p38 mitogen-activated protein kinase in vivo and extracellular signal-related kinase in vitro.

Novel synthesis of nanorod ZnO and Fe-doped ZnO by the hydrolysis of metal powders

Fe-doped ZnO nanorods have been synthesized by a novel process employing a hydrolysis of metal powders. Zn and Fe nano-powders were used as starting materials and incorporated into distilled water. The solution was refluxed at 60 degrees C for 24 h to obtain the precipitates from the hydrolysis of Zn and Fe. X-ray diffraction patterns for all the samples showed a pure wurtzite single phase, without any segregation of the Fe into the particulates within the instrumental resolution limit. The TEM results for ZnO with and without an Fe-doping showed that the produced powders had a rod-like shape. The rod shape was attributable to the zinc oxide from the hydrolysis of Zn. With an increasing Fe content, the UV-vis spectra were shifted to a long wave length and this result indicates that the band gap was changed by an Fe-doping.

Vestibular diagnosis as prognostic indicator in sudden hearing loss with vertigo

The majority of episodes of sudden hearing loss are caused by inner ear disorders, often accompanied by vertigo. The patterns of hearing loss usually influence the prognosis. The purpose of this study was to analyze vestibular diagnoses in sudden hearing loss with vertigo, and to correlate them with the recovery of hearing loss. The clinical records of 125 patients with sudden hearing loss were reviewed. Various vestibular evaluations were performed in 36 patients with vertigo. The vertigo in these patients was classified as normal, unilateral hypofunction, directional preponderance, benign paroxysmal positional vertigo (BPPV), non-specific or irritative. The initial and final pure-tone audiograms of these patients were compared. The distribution of vestibular diagnoses was unilateral hypofunction in 30.6% of patients, BPPV in 25.7%, normal in 19.4%, non-specific in 11.1%, directional preponderance in 8.3% and irritative in 8.3%. The recovery of hearing in patients with vertigo was significantly worse than in those without vertigo. The recovery of hearing in patients with spinning vertigo did not differ from that of patients with non-spinning vertigo. The recovery of hearing was worst in the BPPV group, especially in the high frequency range, followed by the unilateral hypofunction group, who showed hearing thresholds between those in the BPPV group and those in the normal vestibular function test group. This study suggests that the diagnostic classification of vestibulopathy is a useful prognostic indicator of hearing recovery in sudden hearing loss with vertigo. We conclude that otolithic and semicircular canal involvement may cause poor hearing results, especially in the high frequency range.

Syntheses and evaluation of pyrido[2,3-dlpyrimidine-2,4-diones as PDE 4 inhibitors

The syntheses and in vitro evaluation of a new series of pyrido[2,3-d]pyrimidine-2,4-diones bearing substituents at C-3 and/or C-4 positions on the pyridine ring are described. Some of these compounds, especially 51 and 6f, were found to be potent phosphodiesterase 4 (PDE 4) inhibitors exhibiting improved ratio of PDE 4 inhibitory activity:rolipram binding assay (RBA).

Ultrastructural changes in platelet activating factor-induced epithelial damage in rabbit maxillary sinus mucosa

Platelet activating factor (PAF), a potent chemical mediator in inflammation and allergic reaction, has been thought to induce mucociliary inhibition and epithelial damage in the airway mucosa. However, several recent papers have reported that PAF may not readily damage the airway epithelium. The aim of this study was to elucidate the pathogenesis of PAF-induced epithelial damage in terms of ultrastructural changes. Sixteen micrograms of PAF (1 mL of 16 microg/mL) was administered into the maxillary sinuses of rabbits. The rabbits were divided into 2 groups according to time intervals, and the antral mucosa was taken 1 and 3 days after administration of PAF. The tissue was processed for routine transmission electron microscopy. No epithelial degeneration was observed other than platelet aggregation, red blood cell stasis, and swelling of the endothelial cells 1 day after administration of PAF. Migration of inflammatory cells into the perivascular connective tissue, infiltration of eosinophils into the subepithelial and intraepithelial spaces, and vacuolar degeneration of the epithelial cells with focal loss of cilia were seen 3 days after administration of PAF. In conclusion, PAF induced infiltration of eosinophils into the epithelium, and resulted in epithelial degeneration that varied according to the time interval. Our findings suggest that PAF may cause epithelial damage through a series of secondary events, probably due to cytotoxicity of eosinophils infiltrating the epithelium.

Intratumoral hypericin and KTP laser therapy for transplanted squamous cell carcinoma

OBJECTIVES/HYPOTHESIS

To test intratumoral photodynamic therapy (IPDT) as a new treatment for squamous cell carcinoma in a preclinical tumor model.

STUDY DESIGN AND METHODS

Human P3 squamous carcinoma cells were transplanted subcutaneously in athymic nude mice and allowed to grow into 300- to 500-mm3 tumors. Hypericin dye at 1 microg/gm of body weight was injected intratumorally (IT) or intravenously (IV). After 4 hours hypericin biodistribution was assessed in ethanol extracts from tissues by fluorescence spectroscopy. IPDT also was tested by KTP laser fiberoptic insertion in tumors 4 hours after IT dye injection compared to KTP532 laser therapy alone (532 nm, 1W, 40-60 J, 0.6-mm fiber).

RESULTS

Hypericin concentration in tissues was as follows: (IT vs. IV) for tumors (3660 vs. 135 ng dye/gm tissue), lung (760 vs. 6345), liver (75 vs. 935), blood (65 vs. 480) compared to skin (465 vs. 110) or muscle (335 vs. 80) adjacent to the squamous cell tumors. Four hours after dye injection, the tumor exhibited bright orange fluorescence when excited by KTP 532-nm green laser light. The IPDT-treated tumors had a 3.32+/-0.32-mm radius of cell destruction when H&E-stained sections were examined compared with 2.5+/-0.38 mm for the laser only control group (n = 10, P = .003).

CONCLUSIONS

This pilot study indicates laser IPDT with hypericin induces a significant increase in tumor necrosis compared with laser alone and may be useful as a less invasive adjuvant treatment for recurrent or inoperable human squamous cell cancers of the head and neck.

Arachidonic acid metabolites in antrochoanal polyp and nasal polyp associated with chronic paranasal sinusitis

The aim of this study was to investigate the role of arachidonic acid metabolites (AAMs) in the pathogenesis of antrochoanal polyp (ACP). Using high-performance liquid chromatography (HPLC), we assayed the tissue concentrations of 6-keto-PGF1alpha, leukotrienes (LTs) and hydroxyeicosatetraenoic acids (HETE). Concentrations of AAMs in ACP were compared with the level in the control turbinate tissues and nasal polyps associated with chronic paranasal sinusitis (NPS). The concentrations of 6-keto-PGF1alpha were not significantly different in the control turbinate, ACP and NPS groups. In ACP, concentrations of LTC4, 15-HETE and 12-HETE were significantly lower than in the control turbinate. The striking differences in the profile of AAMs between ACP and NPS included a lack of production of LTD4 and LTE4 in ACP, also detectable in NPS, and markedly lower concentrations of 15-HETE and 12-HETE in ACP. The results of this study indicate that decreased lipoxygenase pathway products in arachidonic acid metabolism may be involved in the pathogenesis of ACP. However, in the pathogenesis of NPS, increased production of LTD4 and LTE4 may have an important role. Taken together, our results demonstrate a difference in pathogenesis between ACP and NPS, particularly in terms of arachidonic acid metabolism.

Effects of leukotrienes and prostaglandins on cochlear blood flow in the chinchilla

Prostaglandins (PGs) such as PGE2 and PGI2 are vasodilators, and leukotrienes (LTs) such as LTB4 and LTC4 are vasoconstrictors. Our previous studies have shown that salicylate ototoxicity is associated with decreased levels of PGs and increased levels of LTs. We hypothesized that vasodilating PGs increase cochlear blood flow and vasoconstricting LTs decrease cochlear blood flow. PGE2, Iloprost (a PGI2 analog), LTB4, and LTC4 were applied to the round window membranes of chinchillas and cochlear blood flow was measured with a laser Doppler flowmeter. PGE2 increased cochlear blood flow, while LTC4 decreased cochlear blood flow. This findings show that vasodilating PGs may have therapeutic implications for sensorineural hearing loss and/or vertigo by increasing cochlear blood flow. Vasoconstricting LTs may cause hearing loss by decreasing cochlear blood flow.

Audiologic evaluation of neonates with severe hyperbilirubinemia using transiently evoked otoacoustic emissions and auditory brainstem responses

OBJECTIVES

To audiologically clarify the lesion site and to test the reliability of transiently evoked otoacoustic emissions (TEOAEs) in hearing screening of hyperbilirubinemic neonates.

STUDY DESIGN

Eleven neonates with severe hyperbilirubinemia who had exchange transfusion in the neonatal intensive care unit of an academic hospital over a 3-year period were included in this study. They were tested with auditory brainstem response (ABR) and TEOAEs after exchange transfusion during hospitalization or at an immediate follow-up visit after discharge. Follow-up ABR tests were performed when infants showed significant hearing loss.

METHODS

ABR and TEOAE tests were performed on the 11 neonates with severe hyperbilirubinemia after exchange transfusion. Follow-up ABR tests were carried out in 3-month intervals in the four neonates who showed abnormal or no response on initial ABR.

RESULTS

Four neonates showed abnormal or no response and the other seven demonstrated normal response in ABR. All 11 neonates passed TEOAEs. Two neonates showed improvement in auditory function at 3- or 6-month follow-up ABR.

CONCLUSION

The results of this study indicate that the site of lesion in hearing loss caused by hyperbilirubinemia may be at the retrocochlear location while the cochlea remains intact. TEOAEs may have limitations in evaluation of hearing in the neonates with hyperbilirubinemia.

Effect of platelet activating factor and its antagonist on the mucociliary clearance of the eustachian tube in guinea pigs

The purpose of this study was to test whether platelet activating factor (PAF) impairs the mucociliary clearance function of the eustachian tube (ET) in a dose-dependent manner and whether PAF antagonist can prevent the impairment of mucociliary function of the ET induced by PAF. Coomassie brilliant blue dye transport time (DTT) in normal guinea pigs was 69 seconds. The DTTs after the application of normal saline and PAF at I and 2 microg/mL into bullae were 66, 74, and 157 seconds. The time was over 15 minutes when 4, 8, and 16 microg/mL of PAF were applied. The DTT was 62 seconds when the animals were pretreated with PAF antagonist (WEB 2170). There were significant delays of the DTTs after treatment with 2, 4, 8, and 16 microg/mL of PAF. Histopathologic examination of ETs from groups with a significant delay in DTTs showed intact cilia, mucous plugs, increased inflammatory cells, and exfoliation of cells. This study demonstrated that PAF impaired the mucociliary clearance function of the ET in a dose-dependent manner. This impairment of mucociliary clearance function was prevented by pretreatment with PAF antagonist. The findings of the study suggest that PAF plays an important role in the pathogenesis of otitis media with effusion by impairing the ET clearance function.

Synthesis and biological studies of catechol ether type derivatives as potential phosphodiesterase (PDE) IV inhibitors

New series of catechol ether type derivatives 5, 6 have been synthesized and applied to biological tests. Even though it is a preliminary data, some of our target molecules show the promising result against PDE IV inhibition. SAR and biological studies with synthetic compounds will be discussed in detail.

Effects of middle ear effusion on transient evoked otoacoustic emissions in children

In order to assess the applicability of transient evoked otoacoustic emissions (TEOAEs) measurements on the sequential monitoring of children with middle ear effusion (MEE), the effects of MEE on TEOAEs response were investigated. TEOAEs responses were recorded on 56 ears of 33 patients before and after tympanostomy tube placement. In the 37 ears with MEE seen at myringotomy, the average band reproducibility below 2 kHz recovered significantly after tube placement, whereas the average band reproducibility at 5 kHz diminished. In the 19 ears without MEE, no significant changes in echo amplitude and band reproducibility were noted in the post-operative TEOAEs measurements compared with pre-operative ones. The results of this study suggest that an improvement in echo response and band reproducibility below 2 kHz in serial TEOAEs measurements may indicate resolution of MEE in children with otitis media with effusion.

Correlation between anthropometric measurements of the oropharyngeal area and severity of apnea in patients with snoring and obstructive sleep apnea

The aim of this study was to investigate the relationship between severity of apnea and anthropometric oropharyngeal measurements in patients with snoring and obstructive sleep apnea. A total of 22 patients complaining of snoring and apneic spell during sleep were evaluated by polysomnographic and anthropometric measurements of the oropharyngeal area. The horizontal width of the uvula at the mid-point and the length of the uvula were measured using a T-shaped ruler. The distance between the anterior pillars, posterior pillars and retromolar raphes were also measured. The correlation between these anthropometric measurements and polysomnographic parameters including the respiratory disturbance index (RDI) and the lowest arterial O2 saturation level (lowest SaO2) of the patients were analyzed. Of the anthropometric measurements, the horizontal width of the uvula showed a significant correlation with RDI and lowest SaO2. The results of the present study indicate that patients with broader uvula may have severer sleep apnea and that anthropometric oropharyngeal measurements may give additional information to polysomnographic findings for selecting surgical candidates.

Effects of platelet activating factor on vascular permeability of the middle ear mucosa

Platelet activating factor (PAF), a potent inflammatory mediator, seems to play a significant role in the pathogenesis of otitis media with effusion (OME), along with other inflammatory mediators such as leukotrienes and prostaglandins. The purpose of this study was to investigate the effect of PAF on the vascular permeability of middle ear mucosa, in an experimental OME model using chinchillas. We injected PAF in doses of 1, 4, 8, and 16 micrograms and normal saline as a control into the bullae of chinchillas. Vascular permeability was measured by the Evans blue vital dye technique. All the PAF-injected animals showed a significant increase in middle ear vascular permeability compared to the control group. This study demonstrated that PAF in the middle ear cavity contributes significantly to the development of OME by increasing the vascular permeability of the middle ear mucosa.

The superiorly based flap long-term tracheostomy in pediatric patients

PURPOSE

Tracheostomy is commonly used to provide control of the upper airway in pediatric patients. The traditional approach, which uses a midline vertical incision in the anterior tracheal wall, is associated with relatively high rates of complications when it is used on a long-term basis. Alternative approaches, such as removing tracheal window or creating tracheal flaps, have been avoided in the pediatric patient because of the risk of tracheal stenosis and the potential for the subsequent effect on tracheal growth. The superiorly based flap tracheostomy (SBFT) has greatly reduced these risks in adults and offers better stomal maintenance, safety, and patient acceptance, but it has not been widely evaluated in pediatric patients.

METHODS

We reviewed 21 superiorly based flap tracheostomies performed in children at our institution between 1986 and 1993. Routine follow-up assessments included fixed and flexible laryngotracheoscopy. Average follow-up was 17 months.

RESULTS

The most common indication for performing the SBFT was bilateral vocal cord paralysis. Short-term complications included wound infection and granuloma in 2 patients. Long-term complications were not observed. One patient died from lower respiratory tract causes. Five of the patients were eventually decannulated, and the stoma closed without laryngotracheal stenosis. Morbidity rates were less and mortality was comparable to those of traditional tracheostomy.

CONCLUSION

We conclude that the SBFT is promising a technique for establishing long-term control of the airway in pediatric patients.

Effect of leukotriene inhibitor on cochlear blood flow in salicylate ototoxicity

Our previous studies showed that salicylate ototoxicity is associated with decreased levels of vasodilating prostaglandins (PGs) and increased vasoconstricting leukotrienes (LTs) in the perilymph and reduced cochlear blood flow (CoBF). The purpose of this study was to test the hypothesis that leukotriene inhibitor prevents salicylate ototoxicity by preventing abnormal elevation of LT levels in the inner ear, thus averting a decrease in CoBF resulting from abnormal levels of arachidonic acid metabolites in the inner ear. Ototoxicity was induced in chinchillas by either local round window membrane (RWM) application or systemic treatment with salicylate both with and without pretreatment with leukotriene inhibitor (Sch 37224). A moderate reduction in CoBF was documented with both local RWM and systemic treatment with salicylate. Salicylate induced hearing loss and reduction in CoBF were prevented by pretreatment with a leukotriene inhibitor. This study suggests that leukotriene inhibitor prevents salicylate ototoxicity by averting a decrease in CoBF mediated by abnormal levels of arachidonic acid metabolites in the inner ear.

Adenomatous lesions of the temporal bone immunohistochemical analysis and theories of histogenesis

Adenomatous lesions of the temporal bone represent a diverse group of neoplasms. At least three histopathologic patterns have been described: glandular; ribbon-like, or "festooning;" and aggressive papillary. Combinations of glandular and ribbon-like histologies in the same lesion are not uncommon. The glandular and ribbon-like histologies have been associated with carcinoid tumors, and the aggressive papillary tumor has been considered a separate entity. Recently, the endolymphatic sac has been proposed as the site of origin of the aggressive papillary lesions. Previous reports have described neuroendocrine properties with characteristics embracing the three histologic types. The authors postulate that the neural crest is the site of origin of this unusual group of neoplasms. Immunohistochemical analysis on the pathologic specimens of patients with adenomatous lesions of the temporal bone was performed to test this hypothesis. From 1975 to 1992 seven patients were treated at the Cleveland Clinic Foundation with a diagnosis of middle ear adenoma. A panel of special stains for neuroectodermal markers, including synaptophysin, chromogranin, neuron specific enolase, calcitonin, and serotonin was used on the paraffin-embedded formalin-fixed specimens. Three lesions were also evaluated by electron microscopy, all demonstrating dense core, intracytoplasmic granules. Three ribbon-like tumors were positive for synaptophysin and chromogranin, and two of these were positive for serotonin. One glandular tumor was positive for synaptophysin, and an aggressive papillary tumor was positive for synaptophysin and neuron specific enolase. An additional papillary tumor was referred following a third recurrence without accompanying immunohistochemical data. Cholesteatoma-like material was identified with a few glandular cells interspersed, all negative by immunohistochemical evaluation. The seventh specimen, initially diagnosed as papillary adenoma on light microscopy, was not studied by the aforementioned stains, and was later identified as a papilloma of sinonasal origin. The neural crest gives rise to pluripotential stem cells with widespread anatomic distribution, including the temporal bone. Because immunomarkers used in this study are specific for neuroectodermal differentiation, results suggest that temporal bone adenomas have neuroendocrine characteristics and could be derived from the specialized neuroectoderm of the neural crest.

Fluorinated o-aminophenol derivatives for measurement of intracellular pH

The simple 2-aminophenol group which serves as a building block for many cationic indicators has been modified to yield a series of pH sensitive probes. This approach is based on the replacement of one of the N-acetate groups of the chelator APTRA (o-aminophenol N,N,O-triacetate) by an N-ethyl group. The resulting series of (N-ethylamino)phenol (NEAP) compounds exhibit pK values in the physiological range and negligible affinity for physiological levels of other ions. Three fluorinated analogs have been prepared: N-ethyl-5-fluoro-2-aminophenol N,O-diacetate (5F NEAP), N-ethyl-2-((2-fluoro-4-carboxybenzyl)oxy)-4-fluoroaniline-N- acetic acid (5F NEAP-2), and 1-(2-(N-ethylamino)-5-fluorophenoxy)-2-(2-fluoro-4- aminophenoxy)ethane-N,N',N'-triacetic acid (5F NEAP-3). These derivatives exhibit total titration shifts of approximately 11 ppm. NEAP-2 and NEAP-3 contain an additional fluorine to serve as an internal chemical shift reference, and NEAP-3, the most highly charged analog prepared, was designed in order to minimize leakage.

Hypericin uptake in rabbits and nude mice transplanted with human squamous cell carcinomas: study of a new sensitizer for laser phototherapy

Tissue uptake and biodistribution of hypericin was measured in rabbits and in nu/nu mice xenografted with P3 human squamous cell carcinoma to assess the value of this dye as an in vivo sensitizer for laser photoinactivation of solid tumors. Hypericin has absorption maxima at 545 and 590 nm with a fluorescence emission peak at 640 nm in ethanol. Dye uptake after intravenous injection was tested at 4 and 24 hours in rabbit tissues by ethanol extraction and quantitative fluorescence spectrophotometry. Maximum dye levels were seen at 4 hours in most vascular organs with lung having fivefold higher uptake than spleen followed by liver, blood, and kidney. Mice were examined after 2, 4, 6, 8, and 24 hours and after 3 and 7 days for dye uptake. The peak concentration of hypericin in murine organs was reached at 4 hours with uptake per gram of tissue as follows: lung > spleen > liver > blood > kidney > heart > gut > tumor > stomach > skin > muscle > brain. Elimination of hypericin was rapid in most murine organs with residual dye under 10% of maximum by 7 days compared to 25% to 30% retention for the squamous cell tumors and several normal tissues. These results suggest that hypericin may be a useful photosensitizer for KTP/532 laser interstitial therapy of human cancer.

Effect of corticosteroid treatment on salicylate ototoxicity

Our previous studies showed that salicylate ototoxicity is associated with decreased levels of prostaglandins (PGs) and elevated levels of leukotrienes (LTs) in the perilymph. The purpose of this study was to determine whether or not pretreatment with corticosteroid, which suppresses both PGs and LTs in arachidonic acid metabolism, prevents salicylate ototoxicity. Salicylate ototoxicity was induced in chinchillas with or without treatment with dexamethasone. Hearing thresholds were measured by auditory brain stem response, and perilymph samples were assayed by high-performance liquid chromatography. Dexamethasone pretreatment, given by either systemic or local round window membrane application, partially prevented salicylate-induced hearing loss. Prevention of salicylate ototoxicity by dexamethasone seems to be correlated with increased PG levels and decreased LT levels in the perilymph. This is another piece of evidence that salicylate ototoxicity may be mediated by abnormal arachidonic acid metabolism in the inner ear.

NMR-sensitive fluorinated and fluorescent intracellular calcium ion indicators with high dissociation constants

A new series of high-dissociation constant (KD) Ca2+ indicators has been developed to reduce perturbations due to buffering of transients, to carry out measurements in cells and organelles with high basal Ca2+ concentrations, and to measure cytosolic Ca2+ levels in the presence of perturbations that may significantly increase these levels. A tetrafluorinated derivative of the chelator 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid, 1,2-bis(2-amino-5,6-difluorophenoxy)ethane-N,N,N',N'-tetraacetic acid (TF-BAPTA), has a KD of 65 microM and exhibits two fluorine nuclear magnetic resonances, one of which is insensitive to Ca2+ chelation and the second of which shifts by approximately 10 ppm upon Ca2+ binding. TF-BAPTA has pK values of approximately 5.0 and Mg2+ dissociation constants > 50 mM. At a field of 8.5 T, the Ca(2+)-sensitive resonance is in fast-intermediate exchange. Correction factors for the effects of intermediate exchange and for the effect of protonation (pK approximately 5.0) and Mg2+ complexation are discussed. An analogous approach has been used to synthesize 2-[2-(5-carboxyoxazole)]-5-[2-(2-bis(carboxymethyl) amino-5,6-difluorophenoxy)]ethoxy-6-bis(carboxymethyl)aminobenz ofuran (fura F), a structural analogue of fura 2, which exhibits fluorescence characteristics similar to those of fura 2, but has a KD of 20 microM.

Ototoxicity of salicylate, nonsteroidal antiinflammatory drugs, and quinine

Salicylates and most NSAIDS in high doses cause mild to moderate temporary hearing loss, either flat or greater in the high frequencies. Hearing loss is accompanied by tinnitus and suprathreshold changes. Salicylates may or may not exacerbate hearing loss and cochlear damage induced by noise. The mechanism of salicylate ototoxicity seems to be multifactorial. Morphologic studies suggest that no permanent cochlear damage occurs with salicylate ototoxicity. Electrophysiologic, morphologic, and in vitro data conclusively demonstrate that salicylate affects outer hair cells. In addition, salicylates appear to decrease cochlear blood flow. Salicylates and NSAIDs inhibit PG-forming cyclooxygenase, and recent studies suggest that abnormal levels of arachidonic acid metabolites consisting of decreased PGs and increased LTs may mediate salicylate ototoxicity. As with salicylate, quinine ototoxicity appears to be multifactorial in origin. The mechanism includes vasoconstriction and decreases in cochlear blood flow, as measured by laser Doppler flowmetry, motion photographic studies, and histologic studies. Reversible alterations of outer hair cells also appear to play an important role, as demonstrated by histology, electron microscopy, isolated hair cell studies, and cochlear potential evaluations. Unlike with salicylate, however, the role of prostaglandins in quinine ototoxicity has not been clearly demonstrated. Also, one of quinine's principal actions, antagonism of calcium-dependent potassium channels, has yet to be investigated for its potential role in ototoxicity.

Experimental otitis media with effusion induced by platelet activating factor

This study tested the hypothesis that platelet activating factor (PAF) in the middle ear can induce otitis media with effusion (OME) and that PAF antagonists can prevent PAF-induced OME. An initial trial of 16 micrograms of PAF was injected into chinchilla bullae, and all ears developed middle ear effusion (MEE) within 48 hours. Subsequent trials were performed to test dose dependency. Interestingly, 1 or 16 micrograms of PAF caused more MEE and inflammation than did 4 or 8 micrograms. A dose of 0.5 micrograms PAF did not cause MEE. Middle ear effusion from injected bullae contained the full spectrum of lipoxygenase and cyclooxygenase products; additionally, more PAF was detected than was injected. Finally, a PAF antagonist (WEB 2170) injected intraperitoneally prevented PAF-induced OME. This study demonstrates that PAF injected into the middle ear can induce OME and that PAF antagonists effectively prevent PAF-induced OME. These findings suggest that PAF plays an important role in the pathogenesis of OME.

Otolaryngologic approach to the diagnosis and management of otitis media

Otitis media is a common childhood disease caused by multiple factors. Understanding the pathogenesis of otitis media is important in the diagnosis and management of it. The mode of therapy should be chosen depending on the type and stage of the disease. Treatment options available to an otolaryngologist include antibiotics, tympanocentesis, myringotomy and tympanostomy tube insertions, adenoidectomy with or without tonsillectomy, exploratory tympanotomy, atympanoplasty, and mastoidectomy.