Refractive Error Change and Overminus Lens Therapy for Childhood Intermittent Exotropia.

Importance: Increased myopic shift was found to be associated with 1 year of overminus spectacle treatment for children with intermittent exotropia (IXT). Persistence of myopic shift after discontinuing overminus spectacles is unknown. Objective: To compare refractive error change over 3 years in children with IXT originally treated with overminus vs nonoverminus spectacles. Design, Setting, and Participants: This study was an 18-month extension of the Trial of Overminus Spectacle Therapy for Intermittent Exotropia cohort, which previously randomized children aged 3 to 10 years with IXT and baseline spherical equivalent refractive error (SER) between -6.00 diopters (D) and 1.00 D to overminus spectacles (-2.50 D for 12 months, -1.25 D for 3 months, and nonoverminus for 3 months) or nonoverminus spectacles. Children were recruited from 56 sites from July 2010 to February 2022. Data were analyzed from February 2022 to January 2024. Interventions: After trial completion at 18 months, participants were followed up at 24 and 36 months. Treatment was at investigator discretion from 18 to 36 months. Main Outcomes and Measures: Change in SER (cycloplegic retinoscopy) from baseline to 36 months. Results: Of 386 children in the Trial of Overminus Spectacle Therapy for Intermittent Exotropia, 223 (57.8%) consented to 18 months of additional follow-up, including 124 of 196 (63.3%) in the overminus treatment group and 99 of 190 (52.1%) in the nonoverminus treatment group. Of 205 children who completed 36-month follow-up, 116 (56.6%) were female, and the mean (SD) age at randomization was 6.2 (2.1) years. Mean (SD) SER change from baseline to 36 months was greater in the overminus group (-0.74 [1.00] D) compared with the nonoverminus group (-0.44 [0.85] D; adjusted difference, -0.36 D; 95% CI, -0.59 to -0.12; P = .003), with 30 of 112 (26.8%) in the overminus group having more than 1 D of myopic shift compared with 14 of 91 (15%) in the nonoverminus group (risk ratio, 1.8; 95% CI, 1.0-3.0). From 12 to 36 months, mean (SD) myopic shift was -0.34 (0.67) D and -0.36 (0.66) D in the overminus and nonoverminus groups, respectively (adjusted difference, -0.001 D; 95% CI, -0.18 to 0.18; P = .99). Conclusions and Relevance: The greater myopic shift observed after 1 year of -2.50-D overminus lens treatment remained at 3 years. Both groups had similar myopic shift during the 2-year period after treatment weaning and cessation. The risk of myopic shift should be discussed with parents when considering overminus lens treatment. Trial Registration: ClinicalTrials.gov Identifier: NCT02807350.

Low-Dose 0.01% Atropine Eye Drops vs Placebo for Myopia Control: A Randomized Clinical Trial.

Importance: Controlling myopia progression is of interest worldwide. Low-dose atropine eye drops have slowed progression in children in East Asia. Objective: To compare atropine, 0.01%, eye drops with placebo for slowing myopia progression in US children. Design, Setting, and Participants: This was a randomized placebo-controlled, double-masked, clinical trial conducted from June 2018 to September 2022. Children aged 5 to 12 years were recruited from 12 community- and institution-based practices in the US. Participating children had low to moderate bilateral myopia (-1.00 diopters [D] to -6.00 D spherical equivalent refractive error [SER]). Intervention: Eligible children were randomly assigned 2:1 to 1 eye drop of atropine, 0.01%, nightly or 1 drop of placebo. Treatment was for 24 months followed by 6 months of observation. Main Outcome and Measures: Automated cycloplegic refraction was performed by masked examiners. The primary outcome was change in SER (mean of both eyes) from baseline to 24 months (receiving treatment); other outcomes included change in SER from baseline to 30 months (not receiving treatment) and change in axial length at both time points. Differences were calculated as atropine minus placebo. Results: A total of 187 children (mean [SD] age, 10.1 [1.8] years; age range, 5.1-12.9 years; 101 female [54%]; 34 Black [18%], 20 East Asian [11%], 30 Hispanic or Latino [16%], 11 multiracial [6%], 6 West/South Asian [3%], 86 White [46%]) were included in the study. A total of 125 children (67%) received atropine, 0.01%, and 62 children (33%) received placebo. Follow-up was completed at 24 months by 119 of 125 children (95%) in the atropine group and 58 of 62 children (94%) in the placebo group. At 30 months, follow-up was completed by 118 of 125 children (94%) in the atropine group and 57 of 62 children (92%) in the placebo group. At the 24-month primary outcome visit, the adjusted mean (95% CI) change in SER from baseline was -0.82 (-0.96 to -0.68) D and -0.80 (-0.98 to -0.62) D in the atropine and placebo groups, respectively (adjusted difference = -0.02 D; 95% CI, -0.19 to +0.15 D; P = .83). At 30 months (6 months not receiving treatment), the adjusted difference in mean SER change from baseline was -0.04 D (95% CI, -0.25 to +0.17 D). Adjusted mean (95% CI) changes in axial length from baseline to 24 months were 0.44 (0.39-0.50) mm and 0.45 (0.37-0.52) mm in the atropine and placebo groups, respectively (adjusted difference = -0.002 mm; 95% CI, -0.106 to 0.102 mm). Adjusted difference in mean axial elongation from baseline to 30 months was +0.009 mm (95% CI, -0.115 to 0.134 mm). Conclusions and Relevance: In this randomized clinical trial of school-aged children in the US with low to moderate myopia, atropine, 0.01%, eye drops administered nightly when compared with placebo did not slow myopia progression or axial elongation. These results do not support use of atropine, 0.01%, eye drops to slow myopia progression or axial elongation in US children. Trial Registration: ClinicalTrials.gov Identifier: NCT03334253.

Relationships among Clinical Factors and Patient-reported Outcome Measures in Adults with Convergence Insufficiency.

SIGNIFICANCE: When exploring relationships among clinical measures and patient-reported outcome measures in adults with convergence insufficiency, worse symptoms (Convergence Insufficiency Symptom Survey [CISS] score) seemed to be correlated with worse reading function domain score (Adult Strabismus-20 quality-of-life questionnaire). After treatment, improved symptoms were associated with improved reading function quality of life. PURPOSE: This study aimed to explore relationships between clinical measures and patient-reported outcome measures in adults undergoing treatment for symptomatic convergence insufficiency. METHODS: In a prospective multicenter observational study, we evaluated adults with symptomatic convergence insufficiency (i.e., clinical measures of near exodeviation, receded near point of convergence, reduced near positive fusional vergence; CISS score ≥21). Fifty-seven participants treated with vision therapy/exercises (n = 35) or base-in prism (n = 22) were analyzed. Spearman correlation coefficients ( R ) were used to assess associations among the three clinical measures and patient-reported outcome measures (CISS, Diplopia Questionnaire, four Adult Strabismus-20 quality-of-life domains) before treatment (baseline) and after 10 weeks and 1 year. Associations were interpreted to be present when the lower limit of the 95% confidence interval (CI) was moderate to strong ( R ≥ 0.4). RESULTS: Among multiple exploratory analyses, the only moderate to strong baseline correlation was between worse CISS and worse Adult Strabismus-20 reading function scores ( R = 0.62; 95% CI, 0.43 to 0.76). Regarding change in measures with treatment, the only moderate to strong correlations were between improved CISS and improved Adult Strabismus-20 reading function scores for prism at 10 weeks ( R = 0.78; 95% CI, 0.52 to 0.91) and 1 year ( R = 0.85; 95% CI, 0.65 to 0.94) and for vision therapy/exercises at 1 year ( R = 0.78; 95% CI, 0.57 to 0.89). CONCLUSIONS: In exploratory analyses, we found positive correlations between CISS symptom scores and reading function quality-of-life scores. The absence of correlations between symptoms and individual clinical measures is consistent with clinical experience that, in convergence insufficiency, symptoms and clinical findings can be discordant.

Parent-provided photographs as an outcome measure for childhood chalazia.

PURPOSE: To determine whether smartphone photographs of children's eyelids are reliable for diagnosing the presence of chalazia. METHODS: In this prospective cross-sectional study, 60 participants, 7 months to 16.5 years of age, at four sites were enrolled; all participants had a chalazion measuring at least 2 mm on at least one eyelid based on an in-person clinical examination by a pediatric eye care professional. Smartphone photographs taken by the parent during the office visit were uploaded to the study website. A masked reader assessed each photograph for the presence or absence of chalazia; results were compared with the gold standard clinical examination results. Sensitivity and specificity for the presence of chalazion by eyelid were calculated. RESULTS: Photographs were available for 240 eyelids; 85 had at least one chalazion and 155 were without a chalazion based on clinical examination. The masked reader correctly classified 68 of 85 eyelids with at least one chalazion and 151 of 155 eyelids without chalazia for a sensitivity of 80% (95% CI, 72%-86%) and a specificity of 97% (95% CI, 94%-99%). Sensitivity improved to 89% for chalazia 5 mm or larger and 94% when superficially located within the eyelid. CONCLUSIONS: Parental smartphone photographs appear to be useful in assessing chalazia in children as an alternative to in-office follow-up examinations. These photographs may be a valuable outcome measure in future clinical trials of chalazia treatment, especially when assessing larger lesions.

Overminus Lens Therapy for Children 3 to 10 Years of Age With Intermittent Exotropia: A Randomized Clinical Trial.

IMPORTANCE: This is the first large-scale randomized clinical trial evaluating the effectiveness and safety of overminus spectacle therapy for treatment of intermittent exotropia (IXT). OBJECTIVE: To evaluate the effectiveness of overminus spectacles to improve distance IXT control. DESIGN, SETTING, AND PARTICIPANTS: This randomized clinical trial conducted at 56 clinical sites between January 2017 and January 2019 associated with the Pediatric Eye Disease Investigator Group enrolled 386 children aged 3 to 10 years with IXT, a mean distance control score of 2 or worse, and a refractive error between 1.00 and -6.00 diopters (D). Data analysis was performed from February to December 2020. INTERVENTIONS: Participants were randomly assigned to overminus spectacle therapy (-2.50 D for 12 months, then -1.25 D for 3 months, followed by nonoverminus spectacles for 3 months) or to nonoverminus spectacle use. MAIN OUTCOMES AND MEASURES: Primary and secondary outcomes were the mean distance IXT control scores of participants examined after 12 months of treatment (primary outcome) and at 18 months (3 months after treatment ended) assessed by an examiner masked to treatment group. Change in refractive error from baseline to 12 months was compared between groups. Analyses were performed using the intention-to-treat population. RESULTS: The mean (SD) age of 196 participants randomized to overminus therapy and 190 participants randomized to nonoverminus treatment was 6.3 (2.1) years, and 226 (59%) were female. Mean distance control at 12 months was better in participants treated with overminus spectacles than with nonoverminus spectacles (1.8 vs 2.8 points; adjusted difference, -0.8; 95% CI, -1.0 to -0.5; P < .001). At 18 months, there was little or no difference in mean distance control between overminus and nonoverminus groups (2.4 vs 2.7 points; adjusted difference, -0.2; 95% CI, -0.5 to 0.04; P = .09). Myopic shift from baseline to 12 months was greater in the overminus than the nonoverminus group (-0.42 D vs -0.04 D; adjusted difference, -0.37 D; 95% CI, -0.49 to -0.26 D; P < .001), with 33 of 189 children (17%) in the overminus group vs 2 of 169 (1%) in the nonoverminus group having a shift higher than 1.00 D. CONCLUSIONS AND RELEVANCE: Children 3 to 10 years of age had improved distance exotropia control when assessed wearing overminus spectacles after 12 months of overminus treatment; however, this treatment was associated with increased myopic shift. The beneficial effect of overminus lens therapy on distance exotropia control was not maintained after treatment was tapered off for 3 months and children were examined 3 months later. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02807350.

A Randomized Clinical Trial of Immediate versus Delayed Glasses for Moderate Hyperopia in 1- and 2-Year-Olds.

PURPOSE: Two strategies were compared for managing moderate hyperopia without manifest strabismus among 1- and 2-year-old children: (1) immediate prescription of glasses versus (2) observation without glasses unless reduced distance visual acuity (VA), reduced stereoacuity, or manifest strabismus. DESIGN: Prospective randomized clinical trial. PARTICIPANTS: A total of 130 children aged 1 to 2 years with hyperopia between +3.00 diopters (D) and +6.00 D spherical equivalent (SE) in at least 1 eye, anisometropia ≤1.50 D SE, and astigmatism ≤1.50 D based on cycloplegic refraction and no manifest strabismus. METHODS: Participants were randomly assigned to glasses (1.00 D less than full cycloplegic hyperopia) versus observation and followed every 6 months for 3 years. Glasses were prescribed to those assigned to observation if they met prespecified deterioration criteria of distance VA or near stereoacuity below age norms, or development of manifest strabismus. MAIN OUTCOME MEASURES: At the 3-year primary outcome examination, participants were classified as failing the randomized management regimen if distance VA or stereoacuity was below age norms or manifest strabismus was observed (each with and without correction in trial frames, confirmed by masked retest, irrespective of whether deterioration had occurred previously), or if strabismus surgery had been performed. RESULTS: Of the 106 participants (82%) completing the 3-year primary outcome examination, failure occurred in 11 (21%) of 53 in the glasses group and 18 (34%) of 53 in the observation group (difference = -13%; 95% confidence interval [CI], -31 to 4; P = 0.14). Sixty-two percent (95% CI, 49-74) in the observation group and 34% (95% CI, 23-48) in the glasses group met deterioration criteria (requiring glasses if not wearing). CONCLUSIONS: For 1- and 2-year-olds with uncorrected moderate hyperopia (+3.00 D to +6.00 D SE), our estimates of failure, after 3 years of 6-month follow-ups, are inconclusive and consistent with a small to moderate benefit or no benefit of immediate prescription of glasses compared with careful observation (with glasses only if deteriorated).

Effect of a Binocular iPad Game vs Part-time Patching in Children Aged 5 to 12 Years With Amblyopia: A Randomized Clinical Trial.

IMPORTANCE: A binocular approach to treating anisometropic and strabismic amblyopia has recently been advocated. Initial studies have yielded promising results, suggesting that a larger randomized clinical trial is warranted. OBJECTIVE: To compare visual acuity (VA) improvement in children with amblyopia treated with a binocular iPad game vs part-time patching. DESIGN, SETTING, AND PARTICIPANTS: A multicenter, noninferiority randomized clinical trial was conducted in community and institutional practices from September 16, 2014, to August 28, 2015. Participants included 385 children aged 5 years to younger than 13 years with amblyopia (20/40 to 20/200, mean 20/63) resulting from strabismus, anisometropia, or both. Participants were randomly assigned to either 16 weeks of a binocular iPad game prescribed for 1 hour a day (190 participants; binocular group) or patching of the fellow eye prescribed for 2 hours a day (195 participants; patching group). Study follow-up visits were scheduled at 4, 8, 12, and 16 weeks. A modified intent-to-treat analysis was performed on participants who completed the 16-week trial. INTERVENTIONS: Binocular iPad game or patching of the fellow eye. MAIN OUTCOMES AND MEASURES: Change in amblyopic-eye VA from baseline to 16 weeks. RESULTS: Of the 385 participants, 187 were female (48.6%); mean (SD) age was 8.5 (1.9) years. At 16 weeks, mean amblyopic-eye VA improved 1.05 lines (2-sided 95% CI, 0.85-1.24 lines) in the binocular group and 1.35 lines (2-sided 95% CI, 1.17-1.54 lines) in the patching group, with an adjusted treatment group difference of 0.31 lines favoring patching (upper limit of the 1-sided 95% CI, 0.53 lines). This upper limit exceeded the prespecified noninferiority limit of 0.5 lines. Only 39 of the 176 participants (22.2%) randomized to the binocular game and with log file data available performed more than 75% of the prescribed treatment (median, 46%; interquartile range, 20%-72%). In younger participants (aged 5 to <7 years) without prior amblyopia treatment, amblyopic-eye VA improved by a mean (SD) of 2.5 (1.5) lines in the binocular group and 2.8 (0.8) lines in the patching group. Adverse effects (including diplopia) were uncommon and of similar frequency between groups. CONCLUSIONS AND RELEVANCE: In children aged 5 to younger than 13 years, amblyopic-eye VA improved with binocular game play and with patching, particularly in younger children (age 5 to <7 years) without prior amblyopia treatment. Although the primary noninferiority analysis was indeterminate, a post hoc analysis suggested that VA improvement with this particular binocular iPad treatment was not as good as with 2 hours of prescribed daily patching. TRIAL REGISTRATION: http://www.clinicaltrials.gov Identifier: NCT02200211.

A Randomized Trial Evaluating Short-term Effectiveness of Overminus Lenses in Children 3 to 6 Years of Age with Intermittent Exotropia.

PURPOSE: To evaluate the short-term effectiveness of overminus spectacles in improving control of childhood intermittent exotropia (IXT). DESIGN: Randomized, clinical trial. PARTICIPANTS: A total of 58 children aged 3 to <7 years with IXT. Eligibility criteria included a distance control score of 2 or worse (mean of 3 measures during a single examination) on a scale of 0 (exophoria) to 5 (constant exotropia) and spherical equivalent refractive error between -6.00 diopters (D) and +1.00 D. METHODS: Children were randomly assigned to overminus spectacles (-2.50 D over cycloplegic refraction) or observation (non-overminus spectacles if needed or no spectacles) for 8 weeks. MAIN OUTCOME MEASURES: The primary outcome was distance control score for each child (mean of 3 measures during a single examination) assessed by a masked examiner at 8 weeks. Outcome testing was conducted with children wearing their study spectacles or plano spectacles for the children in the observation group who did not need spectacles. The primary analysis compared mean 8-week distance control score between treatment groups using an analysis of covariance model that adjusted for baseline distance control, baseline near control, prestudy spectacle wear, and prior IXT treatment. Treatment side effects were evaluated using questionnaires completed by parents. RESULTS: At 8 weeks, mean distance control was better in the 27 children treated with overminus spectacles than in the 31 children who were observed without treatment (2.0 vs. 2.8 points, adjusted difference = -0.75 points favoring the overminus group; 2-sided 95% confidence interval, -1.42 to -0.07 points). Side effects of headaches, eyestrain, avoidance of near activities, and blur appeared similar between treatment groups. CONCLUSIONS: In a pilot randomized clinical trial, overminus spectacles improved distance control at 8 weeks in children aged 3 to <7 years with IXT. A larger and longer randomized trial is warranted to assess the effectiveness of overminus spectacles in treating IXT, particularly the effect on control after overminus treatment has been discontinued.

eQTL of bronchial epithelial cells and bronchial alveolar lavage deciphers GWAS-identified asthma genes.

BACKGROUND: Genome-wide association studies (GWASs) have identified various genes associated with asthma, yet, causal genes or single nucleotide polymorphisms (SNPs) remain elusive. We sought to dissect functional genes/SNPs for asthma by combining expression quantitative trait loci (eQTLs) and GWASs. METHODS: Cis-eQTL analyses of 34 asthma genes were performed in cells from human bronchial epithelial biopsy (BEC, n = 107) and from bronchial alveolar lavage (BAL, n = 94). RESULTS: For TSLP-WDR36 region, rs3806932 (G allele protective against eosinophilic esophagitis) and rs2416257 (A allele associated with lower eosinophil counts and protective against asthma) were correlated with decreased expression of TSLP in BAL (P = 7.9 × 10(-11) and 5.4 × 10(-4) , respectively) and BEC, but not WDR36. Surprisingly, rs1837253 (consistently associated with asthma) showed no correlation with TSLP expression levels. For ORMDL3-GSDMB region, rs8067378 (G allele protective against asthma) was correlated with decreased expression of GSDMB in BEC and BAL (P = 1.3 × 10(-4) and 0.04) but not ORMDL3. rs992969 in the promoter region of IL33 (A allele associated with higher eosinophil counts and risk for asthma) was correlated with increased expression of IL33 in BEC (P = 1.3 × 10(-6) ) but not in BAL. CONCLUSIONS: Our study illustrates cell-type-specific regulation of the expression of asthma-related genes documenting SNPs in TSLP, GSDMB, IL33, HLA-DQB1, C11orf30, DEXI, CDHR3, and ZBTB10 affect asthma risk through cis-regulation of its gene expression. Whenever possible, disease-relevant tissues should be used for transcription analysis. SNPs in TSLP may affect asthma risk through up-regulating TSLP mRNA expression or protein secretion. Further functional studies are warranted.

Juvenile xanthogranuloma--a rare cause of unilateral orbital swelling in an elderly patient.

OBJECTIVE: To report the clinical and pathologic features of an elderly patient with a unilateral orbital swelling and proptosis caused by Juvenile Xanthogranuloma diagnosed and confirmed by orbital biopsy. DESIGN: Interventional case report. PARTICIPANTS: One patient. INTERVENTION: Steroids (Medrol dose pack) and radiation. MAIN OUTCOME MEASURES: Unusual clinical presentation and pathological features of Juvenile Xanthogranuloma in the orbit. CONCLUSIONS: Juvenile Xanthogranuloma affecting one orbit is very rare with unilateral involvement in an elderly patient. Steroids and radiation therapy were very effective in treatment and provided impressive results.

An airway epithelial iNOS-DUOX2-thyroid peroxidase metabolome drives Th1/Th2 nitrative stress in human severe asthma.

Severe refractory asthma is associated with enhanced nitrative stress. To determine the mechanisms for high nitrative stress in human severe asthma (SA), 3-nitrotyrosine (3NT) was compared with Th1 and Th2 cytokine expression. In SA, high 3NT levels were associated with high interferon (IFN)-γ and low interleukin (IL)-13 expression, both of which have been reported to increase inducible nitric oxide synthase (iNOS) in human airway epithelial cells (HAECs). We found that IL-13 and IFN-γ synergistically enhanced iNOS, nitrite, and 3NT, corresponding with increased H(2)O(2). Catalase inhibited whereas superoxide dismutase enhanced 3NT formation, supporting a critical role for H(2)O(2), but not peroxynitrite, in 3NT generation. Dual oxidase-2 (DUOX2), central to H(2)O(2) formation, was also synergistically induced by IL-13 and IFN-γ. The catalysis of nitrite and H(2)O(2) to nitrogen dioxide radical (NO(2)(•)) requires an endogenous peroxidase in this epithelial cell system. Thyroid peroxidase (TPO) was identified by microarray analysis ex vivo as a gene distinguishing HAEC of SA from controls. IFN-γ induced TPO in HAEC and small interfering RNA knockdown decreased nitrated tyrosine residues. Ex vivo, DUOX2, TPO, and iNOS were higher in SA and correlated with 3NT. Thus, a novel iNOS-DUOX2-TPO-NO(2)(•) metabolome drives nitrative stress in HAEC and likely in SA.

Higher blood flow and circulating NO products offset high-altitude hypoxia among Tibetans.

The low barometric pressure at high altitude causes lower arterial oxygen content among Tibetan highlanders, who maintain normal levels of oxygen use as indicated by basal and maximal oxygen consumption levels that are consistent with sea level predictions. This study tested the hypothesis that Tibetans resident at 4,200 m offset physiological hypoxia and achieve normal oxygen delivery by means of higher blood flow enabled by higher levels of bioactive forms of NO, the main endothelial factor regulating blood flow and vascular resistance. The natural experimental study design compared Tibetans at 4,200 m and U.S. residents at 206 m. Eighty-eight Tibetan and 50 U.S. resident volunteers (18-56 years of age, healthy, nonsmoking, nonhypertensive, not pregnant, with normal pulmonary function) participated. Forearm blood flow, an indicator of systemic blood flow, was measured noninvasively by using plethysmography at rest, after breathing supplemental oxygen, and after exercise. The Tibetans had more than double the forearm blood flow of low-altitude residents, resulting in greater than sea level oxygen delivery to tissues. In comparison to sea level controls, Tibetans had >10-fold-higher circulating concentrations of bioactive NO products, including plasma and red blood cell nitrate and nitroso proteins and plasma nitrite, but lower concentrations of iron nitrosyl complexes (HbFeIINO) in red blood cells. This suggests that NO production is increased and that metabolic pathways controlling formation of NO products are regulated differently among Tibetans. These findings shift attention from the traditional focus on pulmonary and hematological systems to vascular factors contributing to adaptation to high-altitude hypoxia.

Human airway epithelial cell determinants of survival and functional phenotype for primary human mast cells.

Mast cells (MCs) are found in increased numbers at airway mucosal surfaces in asthmatic patients. Because human airway epithelial cells (HAECs) actively participate in airway inflammatory responses and are in direct contact with MCs in the mucosa, we hypothesized that HAEC-MC interactions may contribute to the differentiation and survival of MCs in the airway mucosa. Here, we show that HAECs express mRNA and protein for soluble and membrane-bound stem cell factor, releasing soluble stem cell factor into the cell culture supernatant at a concentration of 5.9 +/- 0.1 ng per 10(6) HAEC. HAECs were able to support MC survival in coculture in the absence of any exogenous cytokines for at least 4 d. Before the initiation of coculture, MCs were uniformly tryptase and chymase (MC(TC)) double positive, but by 2 d of coculture the majority of MCs expressed tryptase (MC(T)) alone. MCs supported in coculture generated low amounts of cysteinyl-leukotrienes (cys-LT) after FcepsilonRI-dependent activation (0.2 +/- 0.1 ng of cys-LT per 10(6) cells) and required priming with IL-4 and IL-3 during coculture to achieve a quantity of cys-LT generation within the range expected for human lung mucosal MC (26.5 +/- 16 ng of cys-LT per 10(6) cells). In these culture conditions, HAECs were able to direct mucosal MC protease phenotype, but T cell-derived Th2 cytokines were required for the expression of a functional airway MC eicosanoid phenotype. Thus, distinct cell types may direct unique aspects of reactive mucosal MC phenotype in the airways.

Exhaled breath condensate: methodological recommendations and unresolved questions.

Collection of exhaled breath condensate (EBC) is a noninvasive method for obtaining samples from the lungs. EBC contains large number of mediators including adenosine, ammonia, hydrogen peroxide, isoprostanes, leukotrienes, nitrogen oxides, peptides and cytokines. Concentrations of these mediators are influenced by lung diseases and modulated by therapeutic interventions. Similarly EBC pH also changes in respiratory diseases. The aim of the American Thoracic Society/European Respiratory Society Task Force on EBC was to identify the important methodological issues surrounding EBC collection and assay, to provide recommendations for the measurements and to highlight areas where further research is required. Based on the currently available evidence and the consensus of the expert panel for EBC collection, the following general recommendations were put together for oral sample collection: collect during tidal breathing using a noseclip and a saliva trap; define cooling temperature and collection time (10 min is generally sufficient to obtain 1-2 mL of sample and well tolerated by patients); use inert material for condenser; do not use resistor and do not use filter between the subject and the condenser. These are only general recommendations and certain circumstances may dictate variation from them. Important areas for future research involve: ascertaining mechanisms and site of exhaled breath condensate particle formation; determination of dilution markers; improving reproducibility; employment of EBC in longitudinal studies; and determining the utility of exhaled breath condensate measures for the management of individual patients. These studies are required before recommending this technique for use in clinical practice.

Differential expression of manganese superoxide dismutase and catalase in lung cancer.

Reactive oxygen species (ROS) are important in the initiation and promotion of cells to neoplastic growth. In this context, cigarette smoke exposure, the primary risk factor in lung cancer development, leads to high levels of ROS within the human airway. Although well-equipped with an integrated antioxidant defense system consisting of low-molecular weight antioxidants such as glutathione and intracellular enzymes such as superoxide dismutase (SOD), catalase, and glutathione peroxidase, the lungs are vulnerable to increased endogenous and exogenous oxidative insults. Antioxidants increase in response to oxidative stress and minimize ROS-induced injury in experimental systems, indicating that antioxidant levels may determine whether ROS can initiate lung carcinogenesis. On this basis, we hypothesized that antioxidants would be decreased in lung carcinoma cells as compared with tumor-free adjacent lung tissues. Antioxidant expression was evaluated in 16 lung tumor and 21 tumor-free lung tissues collected between the years 1993 and 2001 from 24 individuals with surgically resectable non-small cell lung cancer, i.e., adenocarcinoma and squamous cell carcinoma. Total SOD activity was increased (P = 0.035), catalase activity decreased (P = 0.002), and glutathione and glutathione peroxidase were similar in tumors compared with tumor-free lung tissues. Alterations in antioxidant activities were attributable to increased manganese SOD and decreased catalase protein and mRNA expression in tumors. Immunohistochemical localization of catalase in the lung revealed decreased or no expression in the tumor cells, although healthy adjacent airway epithelial cells were strongly positive for catalase. Parallel changes in antioxidant activities, protein, and mRNA expression were noted in A549 lung carcinoma cell lines exposed to cytokines (tumor necrosis factor-alpha, interleukin 1beta, and IFN-gamma). Thus, inflammation in the lung may contribute to high levels of manganese SOD and decreased catalase, which together may lead to increased hydrogen peroxide intracellularly and create an intracellular environment favorable to DNA damage and the promotion of cancer.

Alterations in exhaled gas profile during allergen-induced asthmatic response.

The source of exhaled carbon monoxide (CO) and the relationship to airway inflammation are not clear. If CO is produced by the inflamed airway, we hypothesized that inflammation induced by allergen challenge would increase exhaled CO of atopic asthmatics. Eight atopic asthmatics underwent whole lung allergen challenge. CO, nitric oxide (NO), oxygen, and carbon dioxide (CO(2)) were measured simultaneously in exhaled breath which was collected into Mylar balloons before (baseline), immediately after, and at subsequent times after allergen. NO was higher in asthmatics than control subjects at baseline, increased further in seven of the eight asthmatics after allergen, and was inversely correlated to specific conductance. In contrast, exhaled CO of asthmatics was not higher than that of control individuals at baseline, decreased immediately after allergen, and returned to baseline levels during the late asthmatic response. Thus, allergen-induced airway inflammation did not lead to increased exhaled CO in asthma.

Flexible bronchoscopy in molecular biology.

Flexible fiberoptic bronchoscopy has allowed researchers to use the bench to bedside approach in the study and therapy of lung diseases. Through bronchoscopy, the lung is a relatively convenient source of samples for the direct evaluation of human gene expression and function. Sampling of respiratory epithelium is performed by brushing with a cytology brush, whereas the epithelial lining fluid and the inflammatory cells in the bronchoalveolar space are obtained by bronchoalveolar lavage. Furthermore, bronchoscopy has been a cornerstone essential to gene therapy trials for lung disease.

Double-stranded rna dependence of nitric oxide synthase 2 expression in human bronchial epithelial cell lines BET-1A and BEAS-2B.

The human airway epithelium expresses abundant nitric oxide synthase 2 (NOS2) in vivo. Although NOS2 is easily induced by cytokines in primary cultured human airway epithelial cells and lung adenocarcinoma cell line A549, the human bronchial epithelial cell lines BEAS-2B and BET-1A do not express NOS2 in response to cytokines. Mechanisms regulating NOS2 expression in human respiratory epithelial cells are complex, but we have recently shown that NOS2 expression in primary human airway epithelial cells occurs in response to double-stranded RNA (dsRNA) through activation of signaling proteins including nuclear factor (NF)-kappaB and interferon (IFN) regulatory factor (IRF)-1. In this context, we hypothesized that BEAS-2B and BET-1A cells may express NOS2 in response to dsRNA. Here, we show that although cytokines (IFN-gamma, tumor necrosis factor-alpha and interleukin-1beta) do not induce NOS2 expression in BEAS-2B or BET-1A cells, addition of dsRNA to this cytokine mix enables BEAS-2B cells to express NOS2. IFN-gamma and dsRNA induction of NOS2 in BET-1A cells occurs in a serum concentration-dependent manner, with a minimum of 3 d of serum treatment necessary for BET-1A cells to acquire the potential to induce NOS2. Importantly, dsRNA strongly activates NF-kappaB and IRF-1 in BEAS-2B cells, transcription factors essential for NOS2 gene expression in other cell lines. On the basis of these results, dsRNA-activated signaling pathways are clearly important for NOS2 expression in human respiratory epithelial cells. With conditions for NOS2 expression characterized, these cell lines are a convenient in vitro system to investigate the mechanisms regulating NOS2 expression in human respiratory epithelial cells.

Nitric oxide synthase 2 through an autocrine loop via respiratory epithelial cell-derived mediator.

Respiratory epithelium expresses nitric oxide synthase 2 (NOS2) continuously in vivo; however, mechanisms responsible for its expression are only partially understood. We definitively identify an autocrine mechanism of induction and maintenance of NOS2 in human airway epithelial cells through the synthesis and secretion of a soluble mediator. Short exposure of human airway cells to interferon (IFN)-gamma leads to prolonged NOS2 expression. Transfer of the overlying culture medium (conditioned medium) induces NOS2 expression in other airway epithelial cells, suggesting the presence of an intermediary substance regulating NOS2 expression in an autocrine loop. Characterization of the soluble mediator reveals that it is stable and transferable in conditioned medium for up to 7 days. However, soluble mediator does not induce NOS2 mRNA in human alveolar macrophages, indicating that the response to soluble mediator is unique to human respiratory epithelium. Soluble mediator is heat labile but is not inactivated by acid treatment, unlike IFN-gamma itself. Importantly, IFN regulatory factor-1, which is critical for murine NOS2 expression, is expressed and activated by soluble mediator through the signal transducer and activator of transcription-1-dependent pathway. Based on these findings, we propose novel regulatory mechanisms for NOS2 expression in human airway epithelium.