Showing papers by "National Jewish Health published in 2016"

Bacterial and Viral Infections in Atopic Dermatitis: a Comprehensive Review.

Abstract: Atopic dermatitis (AD) is the most common allergic skin disease in the general population. It is a chronic inflammatory skin disease complicated by recurrent bacterial and viral infections that, when left untreated, can lead to significant complications. The current article will review immunologic and molecular mechanisms underlying the propensity of AD patients to microbial infections. These infections include Staphylococcus aureus (S. aureus) skin infections, eczema herpeticum, eczema vaccinatum, and eczema coxsackium. Previous studies have shown that skin barrier defects, a decrease in antimicrobial peptides, increased skin pH, or Th2 cytokines such as IL-4 and IL-13 are potential contributing factors for the increased risk of skin infections in AD. In addition, bacterial virulence such as methicillin-resistant S. aureus (MRSA) produces significantly higher number of superantigens that increase their potential in causing infection and more severe cutaneous inflammation in AD patients. More recent studies suggest that skin microbiome including Staphylococcus epidermidis or other coagulase-negative staphylococci may play an important role in controlling S. aureus skin infections in AD. Other studies also suggest that genetic variants in the innate immune response may predispose AD patients to increased risk of viral skin infections. These genetic variants include thymic stromal lymphopoietin (TSLP), type I interferon (α, s, ω), type II interferon (γ), and molecular pathways that lead to the production of interferons (interferon regulatory factor 2). A common staphylococcal toxin, α-toxin, may also play a role in enhancing herpes simplex virus skin infections in AD. Further understanding of these disease processes may have important clinical implications for the prevention and treatment of skin infections in this common skin disease.

Asthma phenotypes in inner-city children.

Abstract: Background Children with asthma in low-income urban areas have high morbidity. Phenotypic analysis in these children is lacking, but may identify characteristics to inform successful tailored management approaches. Objective We sought to identify distinct asthma phenotypes among inner-city children receiving guidelines-based management. Methods Nine inner-city asthma consortium centers enrolled 717 children aged 6 to 17 years. Data were collected at baseline and prospectively every 2 months for 1 year. Participants' asthma and rhinitis were optimally managed by study physicians on the basis of guidelines. Cluster analysis using 50 baseline and 12 longitudinal variables was performed in 616 participants completing 4 or more follow-up visits. Results Five clusters (designated A through E) were distinguished by indicators of asthma and rhinitis severity, pulmonary physiology, allergy (sensitization and total serum IgE), and allergic inflammation. In comparison to other clusters, cluster A was distinguished by lower allergy/inflammation, minimally symptomatic asthma and rhinitis, and normal pulmonary physiology. Cluster B had highly symptomatic asthma despite high step-level treatment, lower allergy and inflammation, and mildly altered pulmonary physiology. Cluster C had minimally symptomatic asthma and rhinitis, intermediate allergy and inflammation, and mildly impaired pulmonary physiology. Clusters D and E exhibited progressively higher asthma and rhinitis symptoms and allergy/inflammation. Cluster E had the most symptomatic asthma while receiving high step-level treatment and had the highest total serum IgE level (median, 733 kU/L), blood eosinophil count (median, 400 cells/mm 3 ), and allergen sensitizations (15 of 22 tested). Conclusions Allergy distinguishes asthma phenotypes in urban children. Severe asthma often coclusters with highly allergic children. However, a symptomatic phenotype with little allergy or allergic inflammation was identified.

Safety of pirfenidone in patients with idiopathic pulmonary fibrosis: integrated analysis of cumulative data from 5 clinical trials

Abstract: Background Pirfenidone is an oral antifibrotic agent that has been shown to reduce the decline in lung function in patients with idiopathic pulmonary fibrosis (IPF). We performed an integrated analysis of safety data from five clinical trials evaluating pirfenidone in patients with IPF. Methods All patients treated with pirfenidone in the three multinational Phase 3 studies (CAPACITY (studies 004 and 006), ASCEND (study 016)) and two ongoing open-label studies (study 002 and study 012 (RECAP)) were included in the analysis. Safety outcomes were assessed during the period from the first dose until 28 days after the last dose of study drug. Results A total of 1299 patients were included in the analysis. The cumulative total exposure to pirfenidone was 3160 person exposure years (PEY). The median duration of exposure was 1.7 years (range 1 week to 9.9 years), and the mean (±SD) daily dose was 2053.8 (±484.9) mg. Gastrointestinal events (nausea (37.6%), diarrhoea (28.1%), dyspepsia (18.4%), vomiting (15.9%)) and rash (25.0%) were the most common adverse events; these were generally mild to moderate in severity and without significant clinical consequence. Elevations in alanine aminotransferase or aspartate aminotransferase greater than three times the upper limit of normal occurred in 40/1299 (3.1%) patients (adjusted incidence, 2.3 per 100 PEY). Elevations were generally transient and reversible with dose modification or discontinuation. Conclusions A comprehensive analysis of safety outcomes in a large and well-defined cohort of 1299 patients with IPF who were followed prospectively for up to 9.9 years demonstrated that long-term treatment with pirfenidone is safe and generally well tolerated. Trial registration numbers NCT00287716, NCT00287729, NCT00662038, NCT01366209.

Validation of Software Gating: A Practical Technology for Respiratory Motion Correction in PET

Abstract: Purpose To assess the performance of hardware- and software-gating technologies in terms of qualitative and quantitative characteristics of respiratory motion in positron emission tomography (PET) imaging. Materials and Methods Between 2010 and 2013, 219 fluorine 18 fluorodeoxyglucose PET examinations were performed in 116 patients for assessment of pulmonary nodules. All patients provided informed consent in this institutional review board-approved study. Acquisitions were reconstructed as respiratory-gated images by using hardware-derived respiratory triggers and software-derived signal (via an automated postprocessing method). Asymmetry was evaluated in the joint distribution of reader preference, and linear mixed models were used to evaluate differences in outcomes according to gating type. Results In blind reviews of reconstructed gated images, software was selected as superior 16.9% of the time (111 of 657 image sets; 95% confidence interval [CI]: 14.0%, 19.8%), and hardware was selected as superior 6.2% of the time (41 of 657 image sets; 95% CI: 4.4%, 8.1%). Of the image sets, 76.9% (505 of 657; 95% CI: 73.6%, 80.1%) were judged as having indistinguishable motion quality. Quantitative analysis demonstrated that the two gating strategies exhibited similar performance, and the performance of both was significantly different from that of nongated images. The mean increase ± standard deviation in lesion maximum standardized uptake value was 42.2% ± 38.9 between nongated and software-gated images, and lesion full width at half maximum values decreased by 9.9% ± 9.6. Conclusion Compared with vendor-supplied respiratory-gating hardware methods, software gating performed favorably, both qualitatively and quantitatively. Fully automated gating is a feasible approach to motion correction of PET images. (©) RSNA, 2016 Online supplemental material is available for this article.

Normalizing computed tomography data reconstructed with different filter kernels: effect on emphysema quantification

Abstract: Objectives To propose and evaluate a method to reduce variability in emphysema quantification among different computed tomography (CT) reconstructions by normalizing CT data reconstructed with varying kernels Methods We included 369 subjects from the COPDGene study For each subject, spirometry and a chest CT reconstructed with two kernels were obtained using two different scanners Normalization was performed by frequency band decomposition with hierarchical unsharp masking to standardize the energy in each band to a reference value Emphysema scores (ES), the percentage of lung voxels below -950 HU, were computed before and after normalization Bland-Altman analysis and correlation between ES and spirometry before and after normalization were compared Two mixed cohorts, containing data from all scanners and kernels, were created to simulate heterogeneous acquisition parameters Results The average difference in ES between kernels decreased for the scans obtained with both scanners after normalization (77±27 to 03±07; 72±38 to 01±05) Correlation coefficients between ES and FEV1 ,a nd FEV 1/FVC increased significantly for the mixed cohorts Conclusions Normalization of chest CT data reduces variation in emphysema quantification due to reconstruction filters and improves correlation between ES and spirometry Key Points  Emphysema quantification is sensitive to the reconstruction kernel used  Normalization allows comparison of emphysema quantification from images reconstructed with varying kernels  Normalization allows comparison of emphysema quantification obtained with scanners from different manufacturers  Normalization improves correlation of emphysema quantification with spirometry  Normalization can be used to compare data from different studies and centers

Galectin-3 levels are associated with right ventricular functional and morphologic changes in pulmonary arterial hypertension.

Abstract: The response of the right ventricle (RV) to pulmonary arterial hypertension (PAH) involves changes in contractile function, chamber size, hypertrophy, and extracellular matrix (ECM). Galectin-3 (Gal-3) is a mediator of myocardial ECM metabolism and biomarker for left heart remodeling, yet its ability to reflect RV remodeling is unknown. We hypothesized that serum Gal-3 levels correlate with RV morphology and function in PAH, and that Gal-3 is associated with circulating markers of ECM. Fifteen subjects with PAH and 10 age-matched controls underwent same-day echocardiography, cardiac magnetic resonance (CMR) imaging, and phlebotomy for Gal-3 and ECM biomarkers including N-terminal propeptide of type III collagen type (PIIINP), tissue inhibitor of metalloproteinase-1 (TIMP-1), and hyaluronic acid (HA). RV ejection fraction, end diastolic volume index, end systolic volume index, and mass index were calculated using CMR. Echocardiography was used to estimate RV systolic pressure and measure RV strain. Serum Gal-3, TIMP-1, and HA levels were all significantly increased in PAH subjects when compared to controls. Gal-3 correlated with RV ejection fraction (ρ -0.44, p 0.03), end diastolic volume index (ρ 0.42, p 0.03), end systolic volume index (ρ 0.44, p 0.027), mass index (ρ 0.47, p 0.016), systolic pressure (ρ 0.55, p < 0.001), and strain (ρ 0.43, p 0.03). Gal-3 levels positively correlated with the ECM markers TIMP-1 and HA but not with PIIINP. In conclusion, Gal-3 levels are associated with multiple indices of RV function and morphology. Gal-3 may represent a novel biomarker for RV remodeling and associated ECM turnover in PAH.

Treatment of Non-Tuberculous Mycobacterial Lung Disease

Abstract: Treatment of non-tuberculous mycobacterial lung disease (NTM-LD) is challenging for several reasons including the relative resistance of NTM to currently available drugs and the difficulty in tolerating prolonged treatment with multiple drugs. Yet-to-be-done, large, multicenter, prospective randomized studies to establish the best regimens will also be arduous because multiple NTM species are known to cause human lung disease, differences in virulence and response to treatment between different species and strains within a species will make randomization more difficult, the need to distinguish relapse from a new infection, and the difficulty in adhering to the prescribed treatment due to intolerance, toxicity, and/or drug-drug interactions, often necessitating modification of therapeutic regimens. Furthermore, the out-of-state resident status of many patients seen at the relatively few centers that care for large number of NTM-LD patients pose logistical issues in monitoring response to treatment. Thus, current treatment regimens for NTM-LD is largely based on small case series, retrospective analyses, and guidelines based on expert opinions. It has been nearly 10 years since the publication of a consensus guideline for the treatment of NTM-LD. This review is a summary of the available evidence on the treatment of the major NTM-LD until more definitive studies and guidelines become available.

Rituximab for the treatment of connective tissue disease-associated interstitial lung disease

Abstract: Objective: To describe our experience with rituximab (RTX) as treatment for a diverse spectrum of chronic connective tissue disease-associated interstitial lung disease (CTD-ILD). Methods: Twenty-four subjects with CTD-ILD were included. All had pulmonary function testing before and after their first RTX infusion. Each subject was evaluated in a multidisciplinary autoimmune and ILD outpatient clinic. Data were extracted by retrospective review of complete medical records. Results: Most subjects were middle-aged white women with rheumatoid arthritis (RA) (n=15) and a nonspecific interstitial pneumonia (NSIP) pattern on high-resolution chest computed tomography scans (n=17). Sixteen subjects received a corticosteroid-sparing agent at the time of RTX initiation; mostly mycophenolate mofetil (n=8). RTX administration was not associated with corticosteroid-sparing effects: 13 subjects were on prednisone at the time of the initial RTX cycle, and 9 remained on prednisone at 6 months after (mean daily dosage 10.2±16.2 mg before vs. 5.6±11.0 mg after, p=0.27). RTX had no appreciable effect on pulmonary physiology; however, individual trajectories for percentage predicted forced vital capacity (FVC%) were highly variable. The underlying CTD (RA vs. non-RA) and ILD pattern did not appear to affect response to RTX. Among 14 subjects who received multiple RTX cycles, FVC% trajectories were variable: FVC% increased in eight and declined in six. Respiratory infections were the most common post-RTX adverse event. Conclusion: In this small, retrospective study of chronic CTD-ILD, RTX was not associated with changes in FVC% or corticosteroid-sparing effects. Controlled, prospective studies are needed to more confidently define the effects of RTX in CTD-ILD. (Sarcoidosis Vasc Diffuse Lung Dis 2015; 32: 296-304)

Measurement of utility in asthma: evidence indicating that generic instruments may miss clinically important changes.

Abstract: Accurate assessment of preference-based health-related quality of life is important in determining the value of asthma interventions. To examine the sensitivity and responsiveness of the EQ-5D and the AQL-5D to differences in asthma control measured by the Asthma Control Questionnaire (ACQ-5). The Observational Study of Asthma Control and Outcomes was a prospective survey of persistent asthma patients ≥12 years old in Kaiser Colorado. Patients received a survey three times in 1 year, including the ACQ-5, AQL-5D and EQ-5D-3L (including VAS). Censored Least Absolute Deviations (CLAD) and logistic regression were used, controlling for sociodemographics and smoking. There were 6666 completed surveys (1799 individuals completed all three survey waves). After controlling for covariates, each one-point increase in ACQ-5 was associated with a decrease of 0.066, 0.058, 0.074 and 6.12 in EQ-5D(US), EQ-5D(UK), AQL-5D and VAS scores. Uncontrolled asthma (ACQ-5 > 1.5) was associated with a decrease of 0.15, 0.17, 0.11 and 10, respectively (vs. ACQ ≤ 1.5). AQL-5D scores were statistically significantly different across categories of ACQ-5 scores of 0.5 (the minimum clinically important difference [MCID]), while EQ-5D scores were not significant across most categories. The AQL-5D appeared more robust to changes in control over time (responsiveness) compared to EQ-5D-3L. The AQL-5D appears more responsive to changes in asthma control over time and more sensitive to detecting differences corresponding to the ACQ-5 MCID than the EQ-5D-3L. Using the EQ-5D-3L without an asthma-specific measure such as the AQL-5D may miss clinically important changes in asthma control.

Reductions in Negative Parenting Practices Mediate the Effect of a Family–School Intervention for Children With Attention Deficit Hyperactivity Disorder

Abstract: Accumulating research has identified family behavioral interventions as an empirically supported psychosocial treatment for students with attention deficit hyperactivity disorder (ADHD). The mechanisms behind the effectiveness of these interventions, however, have been less well studied. The current study examined possible mediators of improvement in 181 children's homework performance as a result of a family–school intervention for children in Grades 2–6 with ADHD (Family–School Success program, FSS). Specifically, changes in parenting practices and the family–school relationship were examined as potential mediators of the relationship between FSS treatment and improvements in students' homework performance. When we controlled for pretreatment levels of behavior and demographic variables, reductions in negative parenting practices were associated with both parent and teacher reports of homework performance at posttreatment. The relationship between treatment group and teacher reports of homework...

A Special Connection between γδ T Cells and Natural Antibodies

Abstract: Natural antibodies (NAbs) play an important role in early host defense, autophagy and tissue remodeling, and in immune regulation. They arise spontaneously (without specific immunization), and are already present at birth. NAbs are produced by B1 B cells, MZ B cells and other B cell types. They include all major Ig subclasses but IgM antibodies are prevalent, especially early in development. NAbs may be poly-specific, recognize particular auto-antigens, or detect neo-determinants such as those exposed during apoptosis or generated by oxidation. NAbs do not require cognate T cell help but depend on soluble mediators produced by T cells. Our recent studies suggest that γδ T cells may have a special relationship with NAbs, and play a prominent role in their regulation, in part through the fine-tuning of IL-4 levels. The spontaneously activated state of these cells likely enables their cytokine production and other functions in the absence of external stimulation. Ontogenetically, the earlier arising γδ T cells are better positioned than αβ T cells to shape the developing repertoire of NAbs. Intriguingly, ligand specificities of NAbs and γδ T cell receptors appear to be overlapping, perhaps allowing γδ cognate help for certain NAb specificities. Via NAbs, γδ T cells could exert a regulatory influence on numerous processes in health and disease.

Methylation Analysis Reveals Fundamental Differences Between Ethnicity and Genetic Ancestry

Abstract: In clinical practice and biomedical research populations are often divided categorically into distinct racial and ethnic groups. In reality, these categories comprise diverse groups with highly heterogeneous histories, cultures, traditions, religions, as well as social and environmental exposures. While the factors captured by these categories contribute to clinical practice and biomedical research, the use of race/ethnicity is widely debated. As a response to this debate, genetic ancestry has been suggested as a complement or alternative to this categorization. However, few studies have examined the effect of genetic ancestry, racial/ethnic identity, and environmental exposures on biological processes. Herein, we examine the contribution of self-identification within ethnicity, genetic ancestry, and environmental exposures on epigenetic modification of DNA methylation, a phenomenon affected by both genetic and environmental factors. We typed over 450,000 variably methylated CpG sites in primary whole blood of 573 individuals of Mexican and Puerto Rican descent who also had high-density genotype data. We found that methylation levels at a large number of CpG sites were significantly associated with ethnicity even when adjusting for genetic ancestry. In addition, we found an enrichment of ethnicity-associated sites amongst loci previously associated with environmental and social exposures. Interestingly, one of the strongest associated sites is driven by the Duffy Null blood type variant, demonstrating a new function of the locus in lymphocytes. Overall, the methylation changes associated with race/ethnicity, driven by both genes and environment, highlight the importance of measuring and accounting for both self-identified race/ethnicity and genetic ancestry in clinical and biomedical studies and the benefits of studying diverse populations.

Differential methylation between ethnic sub-groups reflects the effect of genetic ancestry and environmental exposures

Abstract: In clinical practice and biomedical research populations are often divided categorically into distinct racial/ethnic groups. In reality, these categories, which are based on social rather than biological constructs, comprise diverse groups with highly heterogeneous histories, cultures, traditions, religions, social and environmental exposures and ancestral backgrounds. Their use is thus widely debated and genetic ancestry has been suggested as a complement or alternative to this categorization. However, few studies have examined the relative contributions of racial/ethnic identity, genetic ancestry, and environmental exposures on well-established and fundamental biological processes. We examined the associations between ethnicity, ancestry, and environmental exposures and DNA methylation. We typed over 450,000 CpG sites in primary whole blood of 573 individuals of diverse Hispanic descent who also had high-density genotype data. We found that both self-identified ethnicity and genetically determined ancestry were significantly associated with methylation levels at a large number of CpG sites (916 and 194, respectively). Among loci differentially methylated between ethnic groups, a median of 75.7% (IQR 45.8% to 92%) of the variance in methylation associated with ethnicity could be accounted for by shared genomic ancestry accounts. We also found significant enrichment (p = 4.2 × 10-64) of ethnicity-associated sites amongst loci previously associated with environmental and social exposures, particularly maternal smoking during pregnancy. Our study suggests that although differential methylation between ethnic groups can be partially explained by the shared genetic ancestry, a significant effect of ethnicity is likely due to environmental, social, or cultural factors, which differ between ethnic groups.

Analysis of pediatric airway morphology using statistical shape modeling.

Abstract: Traditional studies of airway morphology typically focus on individual measurements or relatively simple lumped summary statistics. The purpose of this work was to use statistical shape modeling (SSM) to synthesize a skeleton model of the large bronchi of the pediatric airway tree and to test for overall airway shape differences between two populations. Airway tree anatomy was segmented from volumetric chest computed tomography of 20 control subjects and 20 subjects with cystic fibrosis (CF). Airway centerlines, particularly bifurcation points, provide landmarks for SSM. Multivariate linear and logistic regression was used to examine the relationships between airway shape variation, subject size, and disease state. Leave-one-out cross-validation was performed to test the ability to detect shape differences between control and CF groups. Simulation experiments, using tree shapes with known size and shape variations, were performed as a technical validation. Models were successfully created using SSM methods. Simulations demonstrated that the analysis process can detect shape differences between groups. In clinical data, CF status was discriminated with good accuracy (precision = 0.7, recall = 0.7) in leave-one-out cross-validation. Logistic regression modeling using all subjects showed a good fit (ROC AUC = 0.85) and revealed significant differences in SSM parameters between control and CF groups. The largest mode of shape variation was highly correlated with subject size (R = 0.95, p < 0.001). SSM methodology can be applied to identify shape differences in the airway between two populations. This method suggests that subtle shape differences exist between the CF airway and disease control.

Mechanisms by Which Manganese Porphyrins Affect Signaling in Cancer Cells

Abstract: This chapter explores the role that metalloporphyrins (MnTE-2-PyP, MnTnBuOE-2-PyP, and MnTnHex-2-PyP) play in cancer growth and progression. This review focuses on the effect that metalloporphyrins have on signaling events in cancer cells. The first section reviews published data demonstrating that the redox environment influences cancer growth and progression by regulating cell cycle progression, angiogenesis, invasion, and metastasis. The next section reviews studies performed both in vitro and in vivo demonstrating that the addition of superoxide dismutase (SOD) enzymes reduces cancer growth. Then published data is presented showing that manganese porphyrins, which mimic SOD activity, also inhibit cancer growth. Finally, we review all of the mechanisms that have been published thus far on how manganese porphyrins inhibit cancer growth. Specifically, manganese porphyrins have been shown to alter tumor immunology, metabolism, transcription, and post-translational modifications of target signaling proteins. We hypothesize that by scavenging superoxide and enhancing hydrogen peroxide levels, the manganese porphyrins directly affect redox signaling pathways resulting in reduced tumor growth.

A Practice Quality Improvement Project: Reducing Dose of Routine Chest CT Imaging in a Busy Clinical Practice.

Abstract: The purpose of this report is to describe our experience with the implementation of a practice quality improvement (PQI) project in thoracic imaging as part of the American Board of Radiology Maintenance of Certification process. The goal of this PQI project was to reduce the effective radiation dose of routine chest CT imaging in a busy clinical practice by employing the iDose(4) (Philips Healthcare) iterative reconstruction technique. The dose reduction strategy was implemented in a stepwise process on a single 64-slice CT scanner with a volume of 1141 chest CT scans during the year. In the first annual quarter, a baseline effective dose was established using the standard filtered back projection (FBP) algorithm protocol and standard parameters such as kVp and mAs. The iDose(4) technique was then applied in the second and third annual quarters while keeping all other parameters unchanged. In the fourth quarter, a reduction in kVp was also implemented. Throughout the process, the images were continually evaluated to assure that the image quality was comparable to the standard protocol from multiple other scanners. Utilizing a stepwise approach, the effective radiation dose was reduced by 23.62 and 43.63 % in quarters two and four, respectively, compared to our initial standard protocol with no perceived difference in diagnostic quality. This practice quality improvement project demonstrated a significant reduction in the effective radiation dose of thoracic CT scans in a busy clinical practice.

Erratum to: Analysis of pediatric airway morphology using statistical shape modeling

Abstract: regression modeling using all subjects showed a good fit (ROC AUC = 0.85) and revealed significant differences in SSM parameters between control and CF groups. The largest mode of shape variation was highly correlated with subject size (R = 0.95, p < 0.001). SSM methodology can be applied to identify shape differences in the airway between two populations. This method suggests that subtle shape differences exist between the CF airway and disease control.

Methods of identifying and treating subjects having acute respiratory distress syndrome

Abstract: The present invention is related to novel methods for categorizing and treating subjects having Acute Respiratory Distress Syndrome (ARDS).

Insulin mimotopes and methods of using the same

Abstract: Methods for inhibiting an autoimmune disease by administering to a subject a therapeutically effective amount of a composition that induces conversion of naive T cells into Foxp3+ regulatory T cells to induce immunosuppression in the subject. Methods for detecting in a subject an autoimmune disease or a predisposition to an autoimmune disease, and methods for assessing the efficacy of a therapy for an autoimmune disease, particularly type 1 diabetes.

In Vivo Assessment of Airway Function in the Mouse Model.

Abstract: This chapter describes two procedures commonly used to examine airway function in mice. Airway function can be assessed in vivo using noninvasive or invasive methods. Noninvasive methods can be used to monitor respiratory function in mice without the involvement of restraint, anesthesia, or surgery. The methods allow for multiple animals to be monitored simultaneously and can be used in longitudinal studies requiring repeated measurements on the same animals. Invasive methods are used to assess airway function under anesthesia, in mechanically ventilated mice. Although used as terminal procedure, the invasive methods are most appropriate for direct assessment of lower airway dysfunction.