Judith A Voynow

University of North Carolina at Chapel Hill, Chapel Hill, NC, United States

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Publications (46)197.83 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Diacetyl (DA), a component of artificial butter flavoring, has been linked to the development of bronchiolitis obliterans (BO), a disease of airway epithelial injury and airway fibrosis. The epidermal growth factor receptor (EGFR) ligand, amphiregulin (AREG), has been implicated in other types of epithelial injury and lung fibrosis. We investigated the effects of DA directly on the pulmonary epithelium and we hypothesized that DA exposure would result in epithelial cell shedding of AREG. Consistent with this hypothesis, we demonstrate that DA increases AREG by the pulmonary epithelial cell line NCI-H292 and by multiple independent primary human airway epithelial donors grown under physiologically relevant conditions at the air-liquid interface (ALI). Furthermore, we demonstrate that AREG shedding occurs through a tumor necrosis factor-alpha converting enzyme (TACE)-dependent mechanism via inhibition of TACE activity in epithelial cells using the small molecule inhibitor, TAPI-1, as well as TACE specific siRNA. Finally, we demonstrate supportive in vivo results showing increase AREG transcript and protein levels in the lungs of rodents with DA-induced BO. In summary, our novel in vitro and in vivo observations suggest further study of AREG is warranted in the pathogenesis of DA-induced BO.
    American Journal of Respiratory Cell and Molecular Biology 05/2014; · 4.15 Impact Factor
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    ABSTRACT: Neutrophil elastase (NE) is a major inflammatory mediator in cystic fibrosis (CF) that is a robust predictor of lung disease progression. NE directly causes airway injury via protease activity, and propagates persistent neutrophilic inflammation by upregulation of neutrophil chemokine expression. Despite its key role in the pathogenesis of CF lung disease, there are currently no effective anti-protease therapies available to CF patients. Although heparin is an effective anti-protease and anti-inflammatory agent, its anti-coagulant activity prohibits its use in CF due to risk of pulmonary hemorrhage. In this report, we demonstrate the efficacy of a 2-O, 3-O- desulfated heparin (ODSH), a modified heparin with minimal anti-coagulant activity, to inhibit NE activity and to block NE-induced airway inflammation. Using an established murine model of intratracheal NE-induced airway inflammation, we tested the efficacy of intratracheal ODSH to block NE-generated neutrophil chemoattractants and NE-triggered airway neutrophilic inflammation. ODSH inhibited NE-induced keratinocyte-derived chemoattractant (KC) and high mobility group box 1 (HMGB1) release in bronchoalveolar lavage (BAL). ODSH also blocked NE-stimulated HMGB1 release from murine macrophages in vitro and inhibited NE activity in functional assays consistent with prior reports of anti-protease activity. In summary, this report suggests that ODSH is a promising anti-protease and anti-inflammatory agent that may be useful as an airway therapy in CF.
    American Journal of Respiratory Cell and Molecular Biology 12/2013; · 4.15 Impact Factor
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    ABSTRACT: Despite modern sequencing efforts, the difficulty in assembly of highly repetitive sequence has prevented resolution of human genome gaps, including some in the coding regions of genes with important biological functions. One such gene, MUC5AC, encodes a large, secreted mucin, which is one of the two major secreted mucins in human airways. Currently, the MUC5AC region contains a gap in the human genome reference (hg19) across the large, highly repetitive and complex central exon. This exon region is predicted to contain imperfect tandem repeat sequences and multiple conserved cysteine-rich (CysD) domains. To resolve the MUC5AC genomic gap, we utilized high-fidelity, long polymerase chain reaction, followed by Pacific Biosciences' single molecule real time (SMRT®) sequencing. This technology yielded long sequence reads and robust coverage that allowed for de novo sequence assembly spanning the entire repetitive region. Furthermore, we used SMRT Sequencing of PCR amplicons covering the central exon to identify genetic variation in four individuals. The results demonstrated the presence of segmental duplications of CysD domains, insertions/deletions (indels) of tandem repeats, and single nucleotide variants. Additional studies demonstrated that one of the identified tandem repeat insertions is tagged by non-exonic single nucleotide polymorphisms. Taken together, these data illustrate the successful utility of SMRT Sequencing long reads for de novo assembly of large repetitive sequences to fill the gaps in the human genome. Characterization of the MUC5AC gene and the sequence variation in the central exon will facilitate genetic and functional studies for this critical airway mucin.
    American Journal of Respiratory Cell and Molecular Biology 09/2013; · 4.15 Impact Factor
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    ABSTRACT: Neutrophilic inflammation is associated with chronic airway diseases. It has been observed that human neutrophil elastase (HNE), which is secreted by active neutrophils during inflammation, induces both mucin overproduction and goblet cell metaplasia. Several in vitro studies suggest that tumor necrosis factor-α converting enzyme (TACE) regulates the signaling axis that mediates HNE-induced mucin overproduction; however, it is unknown whether TACE performs a similar function in HNE-induced goblet cell metaplasia in vivo. We conducted this study to determine if the inactivation of Tace gene expression attenuates HNE-induced goblet cell metaplasia in mice. Deletion of Tace is lethal shortly after birth in mice; therefore, we utilized Tace(flox/flox) R26Cre(+/-) ER mice and induced a conditional deletion of Tace using a tamoxifen injection. Wild-type mice were given tamoxifen to control for its effect. Tace conditional deletion mice and wild-type mice were exposed to HNE via nasal instillation three times at three-day intervals and the lungs were harvested on day 11 after initial HNE exposure. Using Periodic acid-Schiff staining and MUC5AC immunohistochemical staining to visualize goblet cells in the lungs, we found that HNE induced goblet cell metaplasia in the wild-type mice and that HNE-induced goblet cell metaplasia was significantly attenuated in the Tace conditional deletion mice. These findings suggest that TACE could be a potential target in the treatment of goblet cell metaplasia in patients with chronic airway diseases.
    AJP Lung Cellular and Molecular Physiology 04/2013; · 3.52 Impact Factor
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    ABSTRACT: Cystic Fibrosis (CF) is a chronic lung disease characterized by chronic neutrophilic airway inflammation and increased levels of neutrophil elastase (NE) in the airways. We have previously reported that NE treatment triggers cell cycle arrest. Cell cycle arrest can lead to senescence, a complete loss of replicative capacity. Importantly, senescent cells can be pro-inflammatory and would perpetuate CF chronic inflammation. By immunohistochemistry, we evaluated whether airway sections from CF and control subjects expressed markers of senescence, including: p16(INK4a) (p16), a cyclin dependent kinase inhibitor, phospho-Histone H2A.X (γH2A.X) and phospho-checkpoint 2 kinase (phospho-Chk2), which are also DNA damage response markers. Compared to airway epithelium from control subjects, CF airway epithelium had increased levels of expression of all three senescence markers. We hypothesized that the high load of NE in the CF airway triggers epithelial senescence by upregulating expression of p16, which inhibits cyclin dependent kinase 4 (CDK4). Normal human bronchial epithelial (NHBE) cells, cultured in air-liquid interface were treated with NE (0, 200 and 500 nM) to induce visible injury. Total cell lysates were collected and evaluated by Western analysis for p16 protein expression and CDK4 kinase activity. NE significantly increased p16 expression and decreased CDK4 kinase activity in NHBE cells. These results support the concept that NE triggers expression of senescence markers in CF airway epithelial cells.
    AJP Lung Cellular and Molecular Physiology 01/2013; · 3.52 Impact Factor
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    ABSTRACT: There is evidence that proteases and antiproteases participate in the iron homeostasis of cells and living systems. We tested the postulate that α-1 antitrypsin (A1AT) polymorphism and the consequent deficiency of this antiprotease in humans are associated with a systemic disruption in iron homeostasis. Archived plasma samples from Alpha-1 Foundation (30 MM, 30 MZ, and 30 ZZ individuals) were analyzed for A1AT, ferritin, transferrin, and C-reactive protein (CRP). Plasma samples were also assayed for metals using inductively coupled plasma atomic emission spectroscopy (ICPAES). Plasma levels of A1AT in MZ and ZZ individuals were approximately 60% and 20% of those for MM individuals respectively. Plasma ferritin concentrations in those with the ZZ genotype were greater relative to those individuals with either MM or MZ genotype. Plasma transferrin for MM, MZ, and ZZ genotypes showed no significant differences. Linear regression analysis revealed a significant (negative) relationship between plasma concentrations of A1AT and ferritin while that between A1AT and transferrin levels was not significant. Plasma CRP concentrations were not significantly different between MM, MZ, and ZZ individuals. ICPAES measurement of metals confirmed elevated plasma concentrations of nonheme iron among ZZ individuals. Nonheme iron concentrations correlated (negatively) with levels of A1AT. A1AT deficiency is associated with evidence of a disruption in iron homeostasis with plasma ferritin and nonheme iron concentrations being elevated among those with the ZZ genotype.
    International Journal of COPD 01/2013; 8:45-51.
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    ABSTRACT: NADPH quinone oxidoreductase 1 (NQO1) is recognized as a major susceptibility gene for ozone-induced pulmonary toxicity. In the absence of NQO1, as can occur by genetic mutation, the human airway is protected from harmful effects of ozone. We recently reported that NQO1-null mice are protected from airway hyperresponsiveness and pulmonary inflammation following ozone exposure. Yet, NQO1 regenerates intracellular antioxidants and therefore should protect the individual from oxidative stress. To explain this paradox, we tested whether in the absence of NQO1, ozone exposure results in increased generation of A2-isoprostane, a cyclopentenone isoprostane that blunts inflammation. Using GC/MS, we found that NQO1-null mice had greater lung tissue levels of D2- and E2-isoprostanes, the precursors of J2-, A2-isoprostanes, both at baseline and following ozone exposure compared to congenic wild-type mice. We confirmed in primary cultures of normal human bronchial epithelial cells, that A2-isoprostane inhibited ozone-induced NF-kB activation and IL-8 regulation. Furthermore, we determined that A2-isoprostane covalently modified the active Cys179 domain in Inhibitory kB Kinase in the presence of ozone in vitro, thus establishing the biochemical basis for A2-isoprostane inhibition of NF-kB. Our results demonstrate that host factors may regulate pulmonary susceptibility to ozone by regulating the generation of A2-isoprostanes in the lung. These observations provide the biochemical basis for the epidemiologic observation that NQO1 regulates pulmonary susceptibility to ozone.
    Journal of Biological Chemistry 12/2012; · 4.65 Impact Factor
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    ABSTRACT: Mucous cell metaplasia (MCM) and neutrophil-predominant airway inflammation are pathological features of chronic inflammatory airway diseases. A signature feature of MCM is increased expression of a major respiratory tract mucin, MUC5AC. Neutrophil elastase (NE) upregulates MUC5AC in primary airway epithelial cells by generating reactive oxygen species, and this response is due in part to upregulation of NADPH quinone oxidoreductase 1 (NQO1) activity. Delivery of NE directly to the airway triggers inflammation and MCM and increases synthesis and secretion of MUC5AC protein from airway epithelial cells. We hypothesized that NE-induced MCM is mediated in vivo by NQO1. Male wild-type and Nqo1-null mice (C57BL/6 background) were exposed to human NE (50 μg) or vehicle via oropharyngeal aspiration on days 1, 4, and 7. On days 8 and 11, lung tissues and bronchoalveolar lavage (BAL) samples were obtained and evaluated for MCM, inflammation, and oxidative stress. MCM, inflammation, and production of specific cytokines, granulocyte-macrophage colony-stimulating factor, macrophage inflammatory protein-2, interleukin-4, and interleukin-5 were diminished in NE-treated Nqo1-null mice compared with NE-treated wild-type mice. However, in contrast to the role of NQO1 in vitro, we demonstrate that NE-treated Nqo1-null mice had greater levels of BAL and lung tissue lipid carbonyls and greater BAL iron on day 11, all consistent with increased oxidative stress. NQO1 is required for NE-induced inflammation and MCM. This model system demonstrates that NE-induced MCM directly correlates with inflammation, but not with oxidative stress.
    AJP Lung Cellular and Molecular Physiology 06/2012; 303(3):L181-8. · 3.52 Impact Factor
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    ABSTRACT: Acute respiratory distress syndrome (ARDS) is characterized by severe hypoxemia, diffuse pulmonary infiltrates and poor lung compliance in the absence of left heart failure1,2. Early pathogenic changes include pulmonary neutrophil sequestration and intravascular fibrin-platelet aggregates3,5. Subsequent injury to the alveolar-capillary barrier leads to increased pulmonary vascular permeability causing progressive lung inflammation and pulmonary edema4. Persistent inflammation frequently leads to fibrosis.
    07/2011: pages 187-195;
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    Judith A Voynow, Apparao Kummarapurugu
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    ABSTRACT: Isoprostanes are prostaglandin (PG)-like compounds generated in vivo following oxidative stress by non-enzymatic peroxidation of polyunsaturated fatty acids, including arachidonic acid. They are named based on their prostane ring structure and by the localization of hydroxyl groups on the carbon side chain; these structural differences result in a broad array of isoprostane molecules with varying biological properties. Generation of specific isoprostanes is also regulated by host cell redox conditions; reducing conditions favor F₂-isoprostane production while under conditions with deficient antioxidant capacity, D₂- and E₂-isoprostanes are formed. F₂-isoprostanes (F₂-isoP) are considered reliable markers of oxidative stress in pulmonary diseases including asthma. Importantly, F₂-isoP and other isoprostanes function as ligands for PG receptors, and potentially other receptors that have not yet been identified. They have been reported to have important biological properties in many organs. In the lung, isoprostanes regulate cellular processes affecting airway smooth muscle tone, neural secretion, epithelial ion flux, endothelial cell adhesion and permeability, and macrophage adhesion and function. In this review, we will summarize the evidence that F₂-isoP functions as a marker of oxidative stress in asthma, and that F₂-isoP and other isoprostanes exert biological effects that contribute to the pathogenesis of asthma. This article is part of a Special Issue entitled Biochemistry of Asthma.
    Biochimica et Biophysica Acta 05/2011; 1810(11):1091-5. · 4.66 Impact Factor
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    ABSTRACT: Patients with chronic obstructive pulmonary disease (COPD) exhibit dominant features of chronic bronchitis, emphysema, and/or asthma, with a common phenotype of airflow obstruction. COPD pulmonary physiology reflects the sum of pathological changes in COPD, which can occur in large central airways, small peripheral airways, and the lung parenchyma. Quantitative or high-resolution computed tomography is used as a surrogate measure for assessment of disease progression. Different biological or molecular markers have been reported that reflect the mechanistic or pathogenic triad of inflammation, proteases, and oxidants and correspond to the different aspects of COPD histopathology. Similar to the pathogenic triad markers, genetic variations or polymorphisms have also been linked to COPD-associated inflammation, protease-antiprotease imbalance, and oxidative stress. Furthermore, in recent years, there have been reports identifying aging-associated mechanistic markers as downstream consequences of the pathogenic triad in the lungs from COPD patients. For this review, the authors have limited their discussion to a review of mechanistic markers and genetic variations and their association with COPD histopathology and disease status.
    International Journal of COPD 01/2011; 6:413-21.
  • Paediatric Respiratory Reviews - PAEDIATR RESPIR REV. 01/2011; 12.
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    ABSTRACT: In a mouse model of neutrophil elastase-induced bronchitis that exhibits goblet cell metaplasia and inflammation, we investigated the effects of intratracheal instillation of the MANS peptide, a peptide identical to the NH(2) terminus of the myristoylated alanine-rich C kinase substrate (MARCKS) on mucin protein airway secretion, inflammation, and airway reactivity. To induce mucus cell metaplasia in the airways, male BALB/c mice were treated repetitively with the serine protease, neutrophil elastase, on days 1, 4, and 7. On day 11, when goblet cell metaplasia was fully developed and profiles of proinflammatory cytokines were maximal, the animals were exposed to aerosolized methacholine after intratracheal instillation of MANS or a missense control peptide (RNS). MANS, but not RNS, attenuated the methacholine-stimulated secretion of the major respiratory mucin protein, Muc5ac (50% reduction). Concurrently, elastase-induced proinflammatory cytokines typically recovered in bronchoalveolar lavage (BAL), including KC, IL-1beta, IL-6, MCP-1, and TNFalpha, were reduced by the MANS peptide (mean levels decreased 50-60%). Secondary to the effects of MANS on mucin secretion and inflammation, mechanical lung function by forced oscillation technique was characterized with respect to airway reactivity in response to cumulative aerosol stimulation with serotonin. The MANS peptide was also found to effectively attenuate airway hyperresponsiveness to serotonin in this airway hypersecretory model. Collectively, these findings support the concept that even in airway epithelia remodeled with goblet cell metaplasia and in a state of mucin hypersecretion, exogenous attenuation of function of MARCKS protein via the MANS peptide decreases airway mucin secretion, inflammation, and hyperreactivity.
    AJP Lung Cellular and Molecular Physiology 09/2010; 299(3):L345-52. · 3.52 Impact Factor
  • Paediatric Respiratory Reviews - PAEDIATR RESPIR REV. 01/2010; 11.
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    ABSTRACT: Alpha-1-antitrypsin (A1AT) deficiency is characterized by increased neutrophil elastase (NE) activity and oxidative stress in the lung. We hypothesized that NE exposure generates reactive oxygen species by increasing lung non-heme iron. To test this hypothesis, we measured bronchoalveolar lavage (BAL) iron and ferritin levels, using inductively coupled plasma (ICP) optical emission spectroscopy and an ELISA respectively, in A1AT-deficient patients and healthy subjects. To confirm the role of NE in regulating lung iron homeostasis, we administered intratracheally NE or control buffer to rats and measured BAL and lung iron and ferritin. Our results demonstrated that A1AT-deficient patients and rats post-elastase exposure have elevated levels of iron and ferritin in the BAL. To investigate the mechanism of NE-induced increased iron levels, we exposed normal human airway epithelial cells to either NE or control vehicle in the presence or absence of ferritin, and quantified intracellular iron uptake using calcein fluorescence and ICP mass spectroscopy. We also tested whether NE degraded ferritin in vitro using ELISA and western analysis. We demonstrated in vitro that NE increased intracellular non-heme iron levels and degraded ferritin. Our results suggest that NE digests ferritin increasing the extracellular iron pool available for cellular uptake.
    Clinical and Translational Science 10/2009; 2(5):333-9. · 2.33 Impact Factor
  • Judith A Voynow, Bruce K Rubin
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    ABSTRACT: Normal airway mucus lines the epithelial surface and provides an important innate immune function by detoxifying noxious molecules and by trapping and removing pathogens and particulates from the airway via mucociliary clearance. The major macromolecular constituents of normal mucus, the mucin glycoproteins, are large, heavily glycosylated proteins with a defining feature of tandemly repeating sequences of amino acids rich in serine and threonine, the linkage sites for large carbohydrate structures. The mucins are composed of two major families: secreted mucins and membrane-associated mucins. Membrane-associated mucins have been reported to function as cell surface receptors for pathogens and to activate intracellular signaling pathways. The biochemical and cellular functions for secreted mucin glycoproteins have not been definitively assigned. In contrast to normal mucus, sputum production is the hallmark of chronic inflammatory airway diseases such as asthma, chronic bronchitis, and cystic fibrosis (CF). Sputum has altered macromolecular composition and biophysical properties which vary with disease, but unifying features are failure of mucociliary clearance, resulting in airway obstruction, and failure of innate immune properties. Mucin glycoprotein overproduction and hypersecretion are common features of chronic inflammatory airway disease, and this has been the underlying rationale to investigate the mechanisms of mucin gene regulation and mucin secretion. However, in some pathologic conditions such as CF, airway sputum contains little intact mucin and has increased content of several macromolecules including DNA, filamentous actin, lipids, and proteoglycans. This review will highlight the most recent insights on mucus biology in health and disease.
    Chest 03/2009; 135(2):505-12. · 7.13 Impact Factor
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    ABSTRACT: One host susceptibility factor for ozone identified in epidemiologic studies is NAD(P)H quinone oxidoreductase 1 (NQO1). We hypothesized that after ozone exposure, NQO1 is required to increase 8-isoprostane (also known as F(2)-isoprostane) production, a recognized marker of ozone-induced oxidative stress, and to enhance airway inflammation and hyperresponsiveness. In this report, we demonstrate that in contrast to wild-type mice, NQO1-null mice are resistant to ozone and have blunted responses, including decreased production of F(2)-isoprostane and keratinocyte chemokine, decreased airway inflammation, and diminished airway hyperresponsiveness. Importantly, these results in mice correlate with in vitro findings in humans. In primary human airway epithelial cells, inhibition of NQO1 by dicumarol blocks ozone-induced F(2)-isoprostane production and IL-8 gene expression. Together, these results demonstrate that NQO1 modulates cellular redox status and influences the biologic and physiologic effects of ozone.
    American Journal of Respiratory Cell and Molecular Biology 01/2009; 41(1):107-13. · 4.15 Impact Factor
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    ABSTRACT: The purpose of the workshop was to identify still obscure or novel cellular components of the lung, to determine cell function in lung development and in health that impacts on disease, and to decide promising avenues for future research to extract and phenotype these cells. Since robust technologies are now available to identify, sort, purify, culture, and phenotype cells, progress is now within sight to unravel the origins and functional capabilities of lung cells in developmental stages and in disease. The Workshop's agenda was to first discuss the lung's embryologic development, including progenitor and stem cells, and then assess the functional and structural cells in three main compartments of the lung: (1) airway cells in bronchial and bronchiolar epithelium and bronchial glands (basal, secretory, ciliated, Clara, and neuroendocrine cells); (2) alveolar unit cells (Type 1 cells, Type 2 cells, and fibroblasts in the interstitium); and (3) pulmonary vascular cells (endothelial cells from different vascular structures, smooth muscle cells, and adventitial fibroblasts). The main recommendations were to: (1) characterize with better cell markers, both surface and nonsurface, the various cells within the lung, including progenitor cells and stem cells; (2) obtain more knowledge about gene expression in specific cell types in health and disease, which will provide insights into biological and pathologic processes; (3) develop more methodologies for cell culture, isolation, sorting, co-culture, and immortalization; and (4) promote tissue banks to facilitate the procurement of tissue from normal and from diseased lung for analysis at all levels.
    Proceedings of the American Thoracic Society 10/2008; 5(7):763-6.
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    ABSTRACT: The adult human bronchial tree is covered with a continuous layer of epithelial cells that play a critical role in maintaining the conduit for air, and which are central to the defenses of the lung against inhaled environmental concomitants. The epithelial sheet functions as an interdependent unit with the other lung components. Importantly, the structure and/or function of airway epithelium is deranged in major lung disorders, including chronic obstructive pulmonary disease, asthma, and bronchogenic carcinoma. Investigations regarding the airway epithelium have led to many advances over the past few decades, but new developments in genetics and stem cell/progenitor cell biology have opened the door to understanding how the airway epithelium is developed and maintained, and how it responds to environmental stress. This article provides an overview of the current state of knowledge regarding airway epithelial stem/progenitor cells, gene expression, cell-cell interactions, and less frequent cell types, and discusses the challenges for future areas of investigation regarding the airway epithelium in health and disease.
    Proceedings of the American Thoracic Society 10/2008; 5(7):772-7.
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    Judith A Voynow, Bernard M Fischer, Shuo Zheng
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    ABSTRACT: Cystic fibrosis is the most common, inherited fatal disease in Caucasians. The major cause of morbidity and mortality is chronic lung disease due to infection and inflammation in the airways leading to bronchiectasis and respiratory failure. The signature pathologic features of CF lung disease including abnormal mucus obstructing airways, chronic infection with Staphylococcus aureus, Pseudomonas aeruginosa and other gram negative bacteria, and a robust neutrophil-dominant airway inflammation, are exacerbated by unopposed proteases present at high concentrations in the ASL. There is strong evidence that proteases, particularly neutrophil elastase, contribute to the pathology of CF by impairing mucociliary clearance, interfering with innate immune functions, and perpetuating neutrophilic inflammation. The mechanisms employed by proteases to impact airway function in CF will be reviewed.
    The International Journal of Biochemistry & Cell Biology 02/2008; 40(6-7):1238-45. · 4.15 Impact Factor

Publication Stats

1k Citations
197.83 Total Impact Points


  • 2013
    • University of North Carolina at Chapel Hill
      • Cystic Fibrosis and Pulmonary Diseases Research and Treatment Center
      Chapel Hill, NC, United States
  • 1998–2013
    • Duke University Medical Center
      • • Division of Pediatric Pulmonary and Sleep Medicine
      • • Department of Medicine
      • • Department of Pediatrics
      Durham, North Carolina, United States
    • University of Washington Seattle
      • Department of Pediatrics
      Seattle, WA, United States
  • 1995–2006
    • Children's National Medical Center
      • • Center for Genetic Medicine Research
      • • Division of Pulmonary Medicine
      Washington, D. C., DC, United States
  • 2001
    • George Washington University
      Washington, Washington, D.C., United States
  • 1991
    • University of Pennsylvania
      • Department of Pediatrics
      Philadelphia, PA, United States
  • 1988
    • The Children's Hospital of Philadelphia
      • Department of Pediatrics
      Philadelphia, PA, United States