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Introduction and Objectives Patients with cystic fibrosis are often prescribed complex time-consuming medication regimens. We know from studies in chronic diseases that most patients will be at best only partially adherent with their medication. We studied adherence with nebulised therapy in our adult CF clinic, by measuring the actual quantity of medication prescribed as recorded in General Practitioner and hospital computer prescribing records. The results were compared with the CF centre staff's predictions of adherence on an individual patient basis. Methods We requested prescription issue data for 26 patients on nebulised dornase α, colistin and tobramycin both from the patient's general practitioners and from the hospital pharmacy. We compared the actual quantity of medication prescribed to each patient to the expected number of doses that they should have received during a 12-month period and calculated a percentage adherence based on these figures. Based on previous work in our difficult asthma clinic we assigned obtaining =80% of doses as being adherent; =50% but <80% as partially adherent and <50% as non-adherent with the medication. Results Full prescription data were received for 22 of the 26 patients included in the study. Of these 15% (2/13) were adherent; 23% (3/13) were partially adherent and 62% (8/13) were non-adherent with nebulised colistin. 26% (5/19) were adherent; 26% (5/19) were partially adherent and 48% (9/19) were non-adherent with dornase α 100% (8/8) patients were adherent with nebulised tobramycin. The cystic fibrosis team correctly predicted only 40% (111/280) of the respective adherence rates found. Conclusions The use of prescription data provides useful information regarding adult CF patients' adherence with high-cost nebulised therapy. In our clinic adherence rates were low, and CF clinicians were poor at predicting adherence rates in individual patients. Used in isolation prescription data are a useful indicator of non-adherence, but does not accurately measure positive adherence without consideration of other methods of measurement. We are currently extending this study to compare pharmacy issue data with other methods of measuring adherence in adult CF patients. [ABSTRACT FROM AUTHOR]

Primary ciliary dyskinesia (PCD) is a rare genetic disorder characterised by impaired mucociliary clearance leading to irreversible lung damage. In contrast to other rare lung diseases like cystic fibrosis (CF), there are only few clinical trials and limited evidence-based treatments. Management is mainly based on expert opinions and treatment is challenging due to a wide range of clinical manifestations and disease severity. To improve clinical and translational research and facilitate development of new treatments, the clinical trial network for PCD (PCD-CTN) was founded in 2020 under the framework of the European Reference Network (ERN)-LUNG PCD Core. Applications from European PCD sites interested in participating in the PCD-CTN were requested. Inclusion criteria consisted of patient numbers, membership of ERN-LUNG PCD Core, use of associated standards of care, experience in PCD and/or CF clinical research, resources to run clinical trials, good clinical practice (GCP) certifications and institutional support. So far, applications from 22 trial sites in 18 European countries have been approved, including >1400 adult and >1600 paediatric individuals with PCD. The PCD-CTN is headed by a coordinating centre and consists of a steering and executive committee, a data safety monitoring board and committees for protocol review, training and standardisation. A strong association with patient organisations and industrial companies are further cornerstones. All participating trial sites agreed on a code of conduct. As CTNs from other diseases have demonstrated successfully, this newly formed PCD-CTN operates to establish evidence-based treatments for this orphan disease and to bring new personalised treatment approaches to patients., Competing Interests: Conflict of interest: J. Raidt declares grants for Clinical Research Unit “Male Germ Cells: from Genes to Function” (CRU 326) – Subproject RA3522/1-1 from the Deutsche Forschungsgemeinschaft, in connection with the present manuscript; that they are a holder of patent WO 2020/165352 A1 (Treatment of ciliopathies); and an unpaid role as a Deputy Director of PCD-CTN. Conflict of interest: B. Maitre declares unpaid roles as a Deputy Director of PCD-CTN and as a member of the scientific committee of RADICO PCD. Conflict of interest: P. Pennekamp declares research grants to their institution from NEOCYST (BMBF, 01GM1903A); and that they are a holder of patent WO 2020/165352 A1 (Treatment of ciliopathies). Conflict of interest: M. Armengot declares research grant FIS PI19/00949 from Instituto de Salud Carlos III, in connection with the present manuscript. Conflict of interest: M. Boon declares Forton grant 2020-J1810150-217926 from the King Baudouin Foundation, in the 36 months prior to manuscript submission. Conflict of interest: S.B. Carr declares grants to their institution from the National Institute of Health Research (Programme Development Grant 202952; Health Technology Assessment Grant NIHR121889; HTA grant 14/22/23; NIHR RfPb QOL-PCD; NIHR RfPb VALU- CF); consulting fees paid to their institution by Vertex Pharmaceuticals; personal and institutional honoraria from Chiesi Pharmaceuticals; payment to their institution for participation on a Data Safety Monitoring Board or Advisory Board from Profile Pharma, Pharmaxis and Vertex Pharmaceuticals, all in the 36 months prior to manuscript submission; and that they are Chair of the UK CF Registry Steering Committee (payment to their institution) and of the European CF Society Patient Registry Scientific Committee (unpaid). Conflict of interest: M.A. Mall declares research grant 82DZL009B1 from the German Federal Ministry of Education and Research, in connection with the present manuscript. Conflict of interest: M. Narayanan declares that they have been a co-applicant on the National Institute for Health Research – Research for patient benefit (NIHR –RfPB) grant for ‘Parent reported quality of life measures for young children with primary ciliary dyskinesia (QOL-PCD study)’ in the 36 months prior to manuscript submission; and that they are a member of the British Paediatric Respiratory Society executive committee and the British Thoracic Society standards of care committee. Conflict of interest: P. Pohunek declares research grants from the Ministry of Health of the Czech Republic (NV19-07-00210) and Charles University Grant Agency (670119P) in connection with the present manuscript. Conflict of interest: S. Range declares an unpaid role as medical advisor to PCD Support. Conflict of interest: F.C. Ringshausen declares grants to their institution from the German Center for Lung Research (DZL), the German Center for Infection Research (DZIF), IMI (EU/EFPIA), iABC Consortium (including Alaxia, Basilea, Novartis and Polyphor), Mukoviszidose Institute, Novartis, Insmed Germany, Grifols, Bayer and InfectoPharm; consulting fees from Parion, Grifols, Zambon, Insmed and the Helmholtz-Zentrum für Infektionsforschung; payments or honoraria from I!DE Werbeagentur GmbH; Interkongress GmbH; AstraZeneca; Insmed; Grifols and Universitätsklinikum Frankfurt am Main; payment to their institution for expert testimony at the Social Court Cologne; support for attending meetings from German Kartagener Syndrome and PCD PAG and Mukoviszidose e.V; participation on a Data Safety Monitoring Board or Advisory Board for Insmed, Grifols and Shionogi; fees for clinical trial participation paid to their institution by Abbvie, AstraZeneca, Boehringer Ingelheim, Celtaxsys, Corbus, Insmed, Novartis, Parion, University of Dundee, Vertex and Zambon; and honorary roles as Coordinator of the ERN-LUNG Bronchiectasis Core Network, Chair of the German Bronchiectasis Registry PROGNOSIS, Member of the SteerCo of the European Bronchiectasis Registry EMBARC, Member of the SteerCo of the European NTM Registry EMBARC-NTM, Co-Speaker of the Medical Advisory Board of the German Kartagener Syndrome and PCD PAG, Speaker of the Respiratory Infections and TB group of the German Respiratory Society (DGP), Speaker of the Cystic Fibrosis group of German Respiratory Society (DGP), PI of the DZL, member of the protocol review committee of the PCD-CTN and Member of Physician Association of the German Cystic Fibrosis PAG. Conflict of interest: J. Roehmel declares payments or honoraria from Vertex Pharmaceuticals, in the 36 months prior to manuscript submission. Conflict of interest: G. Thouvenin declares unpaid membership of the RADICO PCD scientific committee. Conflict of interest: H. Omran declares grants for Clinical Research Unit “Male Germ Cells: from Genes to Function” (CRU 326) – Subproject RA3522/1-1 from the Deutsche Forschungsgemeinschaft, from Interdisziplinaeres Zentrum für Klinische Forschung Muenster (Om2/009/12; Om2/015/16; Om2/010/20), from BESTCILIA (EU FP7 GA 305404) and from Registry Warehouse (Horizon2020 GA 777295), all in connection with the present manuscript; in addition to grants to their institution from LYSOCIL (Horizon2020 GA n°811087) NEOCYST (BMBF, 01GM1903A) and Transkripttherapie für primäre ziliäre Dyskinesien (Zentrales Innovationsprojekt Mittelstand (ZIM), BMWi; ZF-4610102SK8), in the 36 months prior to manuscript submission; that they are a holder of patent WO 2020/165352 A1 (Treatment of ciliopathies); and unpaid roles as Head of the ERN-LUNG PCD Core and as a member of the PCD Family Support Group medical advisory board. Conflict of interest: K.G. Nielsen declares funding for the present manuscript from the Danish Children's Lung Foundation (Børnelungefonden); and an unpaid role as a Director of the PCD-CTN. Conflict of interest: All other authors declare no competing interests., (Copyright ©The authors 2022.)

Background: Studies in separate cohorts suggest possible discrepancies between inhaled medicines supplied (median 50-60%) and medicines used (median 30-40%). We performed the first study that directly compares CF medicine supply against use to identify the cost of excess medicines supply., Methods: This cross-sectional study included participants from 12 UK adult centres with ≥1 year of continuous adherence data from data-logging nebulisers. Medicine supply was measured as medication possession ratio (MPR) for a 1-year period from the first suitable supply date. Medicine use was measured as electronic data capture (EDC) adherence over the same period. The cost of excess medicines was calculated as whole excess box(es) supplied after accounting for the discrepancy between EDC adherence and MPR with 20% contingency., Results: Among 275 participants, 133 (48.4%) were females and mean age was 30 years (95% CI 29-31 years). Median EDC adherence was 57% (IQR 23-86%), median MPR was 74% (IQR 46-96%) and the discrepancy between measures was median 14% (IQR 2-29%). Even with 20% contingency, mean potential cost of excess medicines was £1,124 (95% CI £855-1,394), ranging from £183 (95% CI £29-338) for EDC adherence ≥80% to £2,017 (95% CI £1,507-2,526) for EDC adherence <50%., Conclusions: This study provides a conservative estimate of excess inhaled medicines supply cost among adults with CF in the UK. The excess supply cost was highest among those with lowest EDC adherence, highlighting the importance of adherence support and supplying medicine according to actual use. MPR provides information about medicine supply but over-estimates actual medicine use., (Copyright © 2021. Published by Elsevier B.V.)

Background: Effects of unit design and shift worked on stress in neonatal intensive care unit (NICU) nurses have not been fully studied., Purpose: To compare stress in NICU nurses who work in single-family room (SFR) or open bay (OBY) units and on nonrotating day or night shift., Methods: Full-time registered nurses (RNs) (n = 72) from a 42-bed SFR and a 131-bed OBY NICU participated in this comparative cross-sectional study. The Nurse Stress Scale (NSS) and within-shift repeated salivary cortisol levels were used to measure stress. The relationship between NSS score and salivary cortisol level was examined using multiple linear regression. Salivary cortisol levels of day versus night shift were compared with mixed-effects linear models., Results: NSS scores were similar for SFR and OBY units (P = .672) and day versus night shift (P = .606). Changes in cortisol level over time (P = .764) and final cortisol level (P = .883) for SFR versus OBY were not significantly different after controlling for shift. Salivary cortisol level of day-shift nurses decreased significantly over time compared with night-shift nurses (P < .001). The final cortisol level was significantly higher for night-shift compared with day-shift nurses (P < .001)., Implications for Practice: Psychological (NSS) and physiologic (salivary cortisol) stress of NICU nurses is similar in established SFR and OBY units. Cortisol levels are higher at the end of shift in nurses who work night shift and may reflect increased physiologic stress., Implications for Research: Strategies are needed for reducing stress in NICU nurses who work night shift., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2021 by The National Association of Neonatal Nurses.)

Background: Lung clearance index (LCI) is a measure of abnormal ventilation distribution derived from the multiple breath inert gas washout (MBW) technique. We aimed to determine the clinical utility of LCI in non-CF bronchiectasis, and to assess two novel MBW parameters that distinguish between increases in LCI due to specific ventilation inequality (LCIvent) and increased respiratory dead space (LCIds)., Methods: Forty-three patients with non-CF bronchiectasis and 18 healthy control subjects underwent MBW using the sulphur hexafluoride wash-in technique, and data from 40 adults with CF were re-analysed. LCIvent and LCIds were calculated using a theoretical two-compartment lung model, and represent the proportional increase in LCI above its ideal value due to specific ventilation inequality and increased respiratory dead space, respectively., Results: LCI was significantly raised in patients with non-CF bronchiectasis compared to healthy controls (9.99 versus 7.28, p < 0.01), and discriminated well between these two groups (area under receiver operating curve = 0.90, versus 0.83 for forced expiratory volume in one second [% predicted]). LCI, LCIvent and LCIds were repeatable (intraclass correlation coefficient > 0.75), and correlated significantly with measures of spirometric airflow obstruction., Conclusion: LCI is repeatable, discriminatory, and is associated with spirometric airflow obstruction in patients with non-CF bronchiectasis. LCIvent and LCIds are a practical and repeatable alternative to phase III slope analysis and may allow a further level of mechanistic information to be extracted from the MBW test in patients with severe ventilation heterogeneity.

Introduction: Deaths from suicide reached a peak in Sri Lanka in 1995. Several interventions reduced the suicide rate of 48.7 per 100,000 in 1995 to 23 per 100,000 in 2006, though it is still a major socioeconomic problem. All suicides have to be reported to the Inquirer of Sudden Death (ISD) or 'Coroner', according to the Criminal Procedure Code., Method: All deaths where a verdict of 'suicide' was given after an inquest at the Coroner's Court, Colombo, in 2006 were studied. Close relations or friends who attended the inquest were interviewed by medically qualified research assistants. Age, sex, marital and occupational status, level of education, living circumstances and method and reasons for the suicide were studied., Results: During 2006, 151 deaths from suicide were documented, of which 93 (62%) were men. The majority (47%) were aged between 20 and 29 years. One-third of the victims was unemployed. At the time of committing suicide, 75% were living with family; 89 (59%) were married and 46 (31%) were single. Poisoning was the cause of death in 66 (44%), 48 (70%) of which were due to pesticides. Burns caused 51 (34%) deaths. Other common causes of death included hanging (11%), jumping in front of a train (7%) and drowning (3%). The commonest reason for suicide was dispute with the spouse/marital disharmony (30%). Other reasons were dispute with parents (8%), financial matters (7%), organic diseases (7%), alcoholism (7%), psychiatric illnesses (6%) and disputes in love affairs (5%). In 29 cases (19%), no definite reason for the suicide was evident., Discussion: Self-poisoning and self-immolation were the commonest methods used to commit suicide. Marital disharmony was the main reason (30%). Psychiatric illnesses were responsible for only 6%. Future interventional activities should include secure access and restriction of the availability of pesticides and drugs, empowering people to manage anger and conflicts, and recognition and treatment of alcoholism and psychiatric illnesses. The success story of the reduction in the incidence of suicides in Sri Lanka should be a lesson to many developing countries where suicide is a major socioeconomic and health issue.

Macrophages in the airways form an important element of immune defense and inflammation. We analyzed induced sputum from airways of patients with CF for the types of macrophages present, their receptor expression, and phagocytic function. In samples from patients and age-matched controls, macrophages were analyzed by multicolor flow cytometry, scavenger receptor expression was studied at the protein and mRNA level, and receptor function was investigated using fluorescent particles. In adult patients with CF, we discovered a pronounced expansion of the small CD14+ DR+ CD68weak+ macrophages to 73 +/- 18% compared with 16 +/- 8% in healthy controls. Expression of the MARCO and CD206 (mannose receptor) was strongly reduced at the mRNA and protein level in sputum macrophages. Antibody-blocking studies showed that MARCO mediates phagocytosis of unopsonized particles. In line with reduced MARCO expression, sputum macrophages in CF showed a deficient uptake of particles (23+/-9% of cells) compared with healthy controls (71+/-15%). The deficiency of MARCO expression in the predominant small sputum macrophages in CF may lead to impaired clearance of inhaled particles with increased inflammation and damage to the CF lung.

Interleukin (IL)-8, the C-X-C chemokine, is a potent neutrophil chemoattractant that has been implicated in a number of inflammatory airway diseases such as cystic fibrosis. Here we tested the hypothesis that bradykinin, an inflammatory mediator and chloride secretagogue, would increase IL-8 generation in airway epithelial cells through autocrine generation of endogenous prostanoids. Bradykinin increased IL-8 generation in both a non-cystic fibrosis (A549) and cystic fibrosis epithelial cell line (CFTE29) that was inhibited by the nonselective cyclooxygenase (COX) inhibitor indomethacin and the COX-2 selective inhibitor NS-398. COX-2 was the only isoform of COX expressed in both cell lines. Furthermore, the COX substrate arachidonic acid and exogenous prostaglandin E(2) both increased IL-8 release in A549 cells. These results suggest that bradykinin may contribute to neutrophilic inflammation in the airway by generation of IL-8 from airway epithelial cells. The dependence of this response on endogenous production of prostanoids by COX-2 suggests that selective COX-2 inhibitors may have a role in the treatment of airway diseases characterized by neutrophilic inflammation such as cystic fibrosis or chronic obstructive pulmonary disease.

The in vitro production of juvenile hormones (JH) was investigated by using corpora allata (CA) of larvae and corpora cardiaca-corpora allata (CC-CA) complexes of adult females of the fall armyworm Spodoptera frugiperda. In female moths, JH release was high compared to that in 5th and 6th instar larvae. Concentrations of 0.11-0.12 mM methionine, 180-200 mM Na(+), 5.8-8.3 mM K(+), 10-50 mM Ca(2+) and a pH range of 5.7-6.3 yielded optimal incorporation of L-[methyl-(3)H] methionine in vitro by CC-CA complexes. The highest hourly incorporation occurred during a 9-h incubation period following a 1.5-h lag-phase. JH release from CC-CA complexes of adult females was shown to be age-dependent with a peak value on day 2 (approx. 4 pmol h(-1) CA(-1)). By a combination of reversed phase (RP)- and normal phase (NP)-high performance liquid chromatography (HPLC), two major labelled products released by the complex were separated. One compound co-migrated with chemically synthesized JH II diol, the second compound with JH III diol. Only traces of JH II and III could be detected in some samples. Gland extracts also contained both the major radiolabelled products. Double labelling experiments using [3H]methionine and [14C]acetate confirmed their de novo synthesis in CC-CA complexes of female moths. The nature of chemically synthesized reference JH III diol was proved by LC-MS (ESI mass spectrometry) and 1H-NMR (nuclear magnetic resonance spectroscopy).

Cyclo-oxygenase (COX) inhibitors may have a role in reducing inflammation in asthma and other pulmonary diseases. COX inhibitors have different selectivities for the two COX isoenzymes (COX 1 and COX 2) which vary between purified enzyme and intact cell preparations. The relative selectivity of COX inhibitors has not been studied in human airway cells. A number of COX inhibitors in cultured human airway cells were compared which exclusively express either COX 1 (primary degree cultured human airway smooth muscle (HASM) cells) or COX 2 (A549 pulmonary epithelial cell-line) as measured by Western blotting. COX activity was assayed by prostaglandin (PG)E2 production following 30 min incubation with 5 mM arachidonic acid. COX activity in both cell types was similar; HASM cells 92.2+/-12.1 ng PGE2 x mg-1 protein, A549 cells 87.7+/-24.4 ng PGE2 mg-1 protein. In HASM cells the median inhibitory concentration (IC50) was >10-5 M for nimesulide, 3.2 x 10-6 M for N-(2-cyclohexyloxy-4-nitrophenyl)-methanesulphonamide (NS398), 1.8 x 10-8 M for flurbiprofen, 6.7 x 10-9 M for indomethacin and >10-5 M for aspirin. In A549 cells the IC50 was 1.8 x 10-9M for nimesulide, 4.1 x 10-9 M for NS398,6.2 x 10-10 M for flurbiprofen, 1.3 x 10-8 M for indomethacin and >10-5 M for aspirin. Sodium valerate had no effect in either HASM or A549 cells. The COX 2:COX 1 selectivity ratio (COX 2 IC50/COX I IC50) was <0.0001 for nimesulide, 0.001 for NS398, 0.03 for flurbiprofen and 1.9 for indomethacin. In conclusion the present study has shown that cyclo-oxygenase inhibitors have a range of selectivities for cyclo-oxygenase 1 and cyclo-oxygenase 2 in intact human airway cells. The relative cyclo-oxygenase 2 selectivity of N-(2-cyclohexyloxy-4-nitrophenyl)-methanesulphonamide and nimesulide may have implications for the treatment of asthma and other inflammatory pulmonary diseases.

Refractoriness to indirect bronchoconstrictor stimuli, is a feature of asthma but the mechanism is poorly understood. This study tested the hypothesis that endogenous nitric oxide (NO) produced during a first bronchoconstrictor challenge protects against subsequent challenge and therefore has a role in the refractory process. The effect of an NO synthase inhibitor, N(G)-mono-methyl-L-arginine (L-NMMA), on refractoriness to sodium metabisulphite (MBS) was investigated in 20 subjects with mild asthma. On visit one, the dose of MBS which caused a 20% fall in forced expiratory volume in one second (FEV1) (PD20) was determined. On visit two, the refractory index (RI) to MBS was determined by challenging the subjects twice with their PD20 of MBS, the second challenge proceeding after recovery from the first. Those showing a refractory index of approximately 30% (10 subjects) inhaled either L-NMMA or placebo followed 5 min later by two challenges with their PD20 of MBS in a double-blind cross over study at two further visits. The dose of L-NMMA used was shown to reduce exhaled NO for a duration sufficient to cover the second MBS challenge However, no significant difference was found between L-NMMA and placebo in maximum fall in FEV1% and area under the curve (AUC) during first or second MBS challenges or in RI on the two study days. It is concluded that subjects with mild asthma show refractoriness to sodium metabisulphite, but that endogenous nitric oxide is unlikely to be involved either in the refractory process or in the response to sodium metabisulphite per se.

We previously showed that cultured human airway smooth-muscle cells (HASMC) contain soluble and particulate guanylyl cyclases (GCs). We studied the desensitization of soluble and particulate GCs in HASMC. Homologous desensitization of soluble GC occurred after incubation with S-nitroso-N-acetyl pencillamine (SNAP). SNAP-dependent desensitization was blocked by hemoglobin, a nitric oxide (NO) scavenger, suggesting that it was due to NO release. Cross-desensitization between SNAP and sodium nitroprusside (SNP) and the lack of thiol reduction after SNAP or SNP treatment suggested that thiol depletion was not involved. Assays for soluble GC activity and experiments using protein synthesis inhibitors suggested that SNAP-dependent desensitization was due to reduced soluble GC. Homologous desensitization of particulate GC occurred after pretreatment with atrial natriuretic peptide (ANP) accompanied by reduced particulate GC activity. Recovery required protein synthesis, suggesting that it was due to reduction in particulate GC. Homologous desensitization to either SNAP or ANP was not altered by phosphodiesterase (PDE) inhibitors, suggesting that increased PDE activity was not involved. Cross-desensitization experiments using SNAP and ANP and experiments using zaprinast to elevate cyclic guanosine monophosphate showed no evidence of heterologous desensitization. Our results suggest that pretreatment of HASMC with SNAP or ANP causes homologous, but not heterologous, desensitization of soluble and particulate GCs, respectively.

Many cystic fibrosis (CF) patients have increased circulating levels of oxidation products and/or decreased antioxidant status. This study investigated whether treatment of pulmonary exacerbations decreased oxidative stress in CF patients. Seventeen adult patients were studied at the beginning and end of treatment with intravenous antibiotics. Plasma concentrations of the antioxidants ascorbic acid, alpha-tocopherol, uric acid and total reduced thiols, together with plasma retinol, lipid hydroperoxides, malondialdehyde and protein carbonyl levels were determined. Median (interquartile range) pretreatment and post-treatment levels were compared using the Wilcoxon signed rank test. Clinical resolution was reflected by improved spirometry. Significant increases were observed in plasma ascorbic acid (pre 30.4 (15.7-38.6) microM, post 35.2 (27.3-49.6) microM), alpha-tocopherol (pre 19.7 (13.6-25.2) microM, post 25.2 (19.3-31.6) microM) and retinol (pre 1.9 (1.5-2.5) microM, post 2.7 (1.7-3.5) microM). No change in plasma total reduced thiols occurred following treatment (pre 409 (366-420) microM, post 392 (366-423) microM), whereas uric acid fell with treatment (pre 307 (274-394) microM, post 260 (216-317) microM). Neither plasma protein carbonyls or malondialdehyde levels altered with treatment (protein carbonyls pre 0.47 (0.28-1.27), post 0.67 (0.42-0.83) nM x mg protein(-1); malondialdehyde pre 0.75 (0.53-1.18), post 0.84 (0.65-1.15) microM). Lipid hydroperoxides levels did decrease following treatment (53 (18-85) versus 17 (10-55) nM). This study demonstrated that treatment of infective exacerbations resulted in increased plasma levels of some antioxidant vitamins. No immediate change in plasma protein oxidation was observed, but lipid oxidation was decreased.

Although guanosine 3',5'-cyclic monophosphate (cGMP) acts as a relaxant second messenger, the regulation of intracellular cGMP has not been comprehensively studied in human airway smooth muscle. We studied the production of cGMP by cultured human airway smooth muscle cells (HASMC) after stimulation with activators of soluble guanylyl cyclase [sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine (SNAP)] and particulate guanylyl cyclase [atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), C-type natriuretic peptide (CNP), and Escherichia coli heat stable enterotoxin (STa)]. cGMP was measured by enzyme-linked immunosorbent assay. Both SNP (10(-6) to 10(-3) M) and SNAP (10(-6) to 10(-3) M) caused concentration-dependent elevation of cGMP in the presence of the nonselective phosphodiesterase (PDE) inhibitor 3-isobutyl-1-methylxanthine (10(-3) M), with cGMP increasing 6- and 15-fold in response to SNP and SNAP, respectively, at the highest concentration tested (10(-3) M). The increases in cGMP in response to SNP (5 x 10(-5) M) and SNAP (10(-5) M) were inhibited by hemoglobin (Hb; 5 x 10(-5) M), a nitric oxide scavenger, and methylene blue (MB; 5 x 10(-4) M), an inhibitor of guanylyl cyclase. cGMP accumulation after SNAP was abolished by both Hb and MB. The response to SNP was inhibited by 79% with Hb and was abolished with MB. ANP, BNP, and CNP (10(-9) to 10(-5) M) + phosphoramidon (10(-6) M) caused a concentration-dependent elevation in cGMP with an order of potency ANP > BNP > CNP. cGMP formation in the presence of the highest concentration of the most potent natriuretic peptide (10(-5) M ANP) was two- to threefold greater than with the highest concentration of SNAP. The increase in cGMP seen with natriuretic peptides was similar in the presence or absence of phosphoramidon, a neutral endopeptidase (NEP) inhibitor, suggesting that NEP is not playing a role in modulating the effect of natriuretic peptides in HASMC. STa (400 IU/ml) had no effect on cGMP levels. SNAP- and ANP-induced cGMP accumulation was increased by the selective type V PDE inhibitors SKF-96231 and zaprinast, suggesting that type V PDE is responsible for cGMP breakdown in HASMC. These results suggest that cultured HASMC contain both soluble and particulate guanylyl cyclases. The order of potency of the natriuretic peptides ANP > BNP > CNP suggests that type A particulate membrane-bound guanylate cyclase predominates.

1. Guanosine 3':5'-cyclic monophosphate (cyclic GMP) is an important second messenger mediating the effects of nitric oxide (NO) and natriuretic peptides. Cyclic GMP pathways regulate several aspects of lung pathophysiology in a number of airway cells. The regulation of this system has not been extensively studied in pulmonary epithelial tissue. 2. We have studied the production of cyclic GMP by suspensions of ovine tracheal epithelial cells in response to activators of soluble guanylyl cyclase (sodium nitroprusside (SNP) and S-nitroso-N-acetyl-penicillamine (SNAP) and particulate guanylyl cyclase (atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), C-type natriuretic peptide (CNP) and E. coli heat stable enterotoxin (STa)). 3. Both 10(-7)-10(-3) M and 10(-7)-10(-3) M SNAP generated a concentration-dependent marked elevation in cyclic GMP production when incubated with 10(-3) M 3-isobutyl-l -methylxanthine (IBMX) (both greater than 25 x baseline values with highest drug concentration). 4. The increase in production of cyclic GMP in response to 10(-6) M SNP and 10(-5) M SNAP was markedly inhibited by both 5 x 10(-5) M haemoglobin (102% and 92% inhibition) and 5 x 10(-5) M methylene blue (82% and 84% inhibition). 5. The increase in cyclic GMP in response to 10(-3) M SNP was measured following co-incubation with the phosphodiesterase inhibitors 10(-7)-10(-3) M IBMX, 10(-7)-10(-4) M milrinone and 10(-7)-10(-4) M SKF 96231. Only 10(-4)-10(-3) M IBMX significantly increased cyclic GMP levels. 6. Cyclic GMP production was also significantly elevated from baseline by 10(-5) M ANP, 10(-5) M BNP, 10(-5) M CNP and 200 iu ml-3 of E. coli STa toxin in the presence of 10(-3) M IBMX. Increases with these natriuretic peptides and STa toxin were smaller in magnitude (2-4 fold) than those seen with SNP and SNAP. CNP was the most potent of the natriuretic peptides studied suggesting type B membrane bound guanylate cyclase is the predominant form expressed. 7. These results suggest that ovine tracheal epithelial cells contain active guanylyl cyclases. The more marked response to SNP and SNAP than to natriuretic peptides suggests that soluble guanylyl cyclase predominates.

The basolateral Na+/K+ ATPase plays a critical role in sodium reabsorption across airway epithelium. Nasal epithelium shows increased Na+/K+ ATPase activity in cystic fibrosis (CF) but Na+/K+ ATPase has not been characterized in human lung epithelium or compared in CF and normal lung. We measured 3[H] ouabain binding and Na+/K+ ATPase activity in human tracheal epithelium and compared Na/K ATPase activity in bronchial epithelium in CF and control subjects. In tracheal epithelium Na+/K+ ATPase pumps were abundant and of high 3[H] ouabain affinity (Kd 4.7 nM, Bmax 38 pmol/mg) and Na+/K+ ATPase activity was 55 +/- 8 nmol/mg protein/min. Bronchial epithelial Na+/K+ ATPase activity was twofold higher in CF patients than in controls. The increased Na+/K+ ATPase activity may contribute to the increased sodium reabsorption seen in cystic fibrosis.