Improving public health information: a data quality intervention in KwaZulu-Natal, South Africa.

OBJECTIVE: To evaluate the effect of an intervention to improve the quality of data used to monitor the prevention of mother-to-child transmission (PMTCT) of the human immunodeficiency virus in South Africa. METHODS: The study involved 58 antenatal clinics and 20 delivery wards (37 urban, 21 rural and 20 semi-urban) in KwaZulu-Natal province that provided PMTCT services and reported data to the District Health Information System. The data improvement intervention, which was implemented between May 2008 and March 2009, involved training on data collection and feedback for health information personnel and programme managers, monthly data reviews and data audits at health-care facilities. Data on six data elements used to monitor PMTCT services and recorded in the information system were compared with source data from health facility registers before, during and after the intervention. Data completeness (i.e. their presence in the system) and accuracy (i.e. being within 10% of their true value) were evaluated. FINDINGS: The level of data completeness increased from 26% before to 64% after the intervention. Similarly, the proportion of data in the information system considered accurate increased from 37% to 65% (P < 0.0001). Moreover, the correlation between data in the information system and those from facility registers rose from 0.54 to 0.92. CONCLUSION: A simple, practical data improvement intervention significantly increased the completeness and accuracy of the data used to monitor PMTCT services in South Africa.

Azithromycin for cystic fibrosis.

During what is a relatively barren time for new therapies for cystic fibrosis (CF), azithromycin has received a lot of attention as a potential treatment for CF lung disease. Laboratory studies suggest that azithromycin may have indirect actions, including anti-inflammatory, in addition to the standard antibacterial properties. The unique pharmacokinetics of azithromycin sets it aside from other macrolide antibiotics, but may result in increased resistance patterns. Three well-designed randomised controlled trials have demonstrated a small but significant improvement in respiratory function (forced expiratory volume in one second) with azithromycin compared with placebo. These trial results are confirmed by a recent meta-analysis. Mild adverse events (wheeze, diarrhoea and nausea) were significantly increased in one trial. There is no clear consensus regarding the correct dose and length of treatment with azithromycin. The present review discusses the role of azithromycin in the management of cystic fibrosis and the need for close monitoring of patients started on this drug. In addition, clinics should liaise closely with their microbiology departments and monitor resistance patterns.

Primary pulmonary lymphangiectasia in infancy and childhood.

Primary pulmonary lymphangiectasia (PPL) is a rare disorder of unknown aetiology characterised by dilatation of the pulmonary lymphatics. PPL is widely reported to have a poor prognosis in the neonatal period and little is known about the clinical features of patients who survive the newborn period. The current authors report the outcome in nine patients diagnosed in infancy with PPL over a 15-yr period at a single university-based hospital clinic and followed for a median of 6 yrs. Although all of the patients initially experienced respiratory distress, respiratory symptoms improved in most patients after infancy and were notably better by the age of 6 yrs. Many patients had poor weight gain in the first years of life, which eventually improved. Radiological scans showed progressive resolution of neonatal infiltrates, but were characterised by hyperinflation and increased interstitial markings in older children. Most patients had evidence of bronchitis and grew pathogenic organisms from quantitative bronchoalveolar lavage culture. Pulmonary function tests showed predominantly obstructive disease that did not deteriorate over time. In conclusion, these results suggest that primary pulmonary lymphangiectasia does not have as dismal a prognosis as previously described and symptoms and clinical findings improve after the first year of life.

Macrolide antibiotics for cystic fibrosis.

BACKGROUND: Chronic severe infection with Pseudomonas aeruginosa, affects many people with cystic fibrosis (CF). There is evidence from the laboratory and from other disease processes that macrolide antibiotics, whilst not directly active against Pseudomonas aeruginosa, may have indirect actions against this organism. OBJECTIVES: We aimed to test the hypotheses that, in people with CF, macrolide antibiotics:(1) improve clinical status compared to placebo or another antibiotic;(2) do not have unacceptable adverse effects. If benefit was demonstrated, we aimed to assess the optimal type, dose and duration of macrolide therapy. SEARCH STRATEGY: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group trials register comprising references identified from comprehensive electronic database searches, handsearching relevant journals and abstract books of conference proceedings. We contacted principal investigators known to work in the field, previous authors and pharmaceutical companies who manufacture macrolide antibiotics for unpublished or follow-up data (December 2003). Most recent search of the Group's register: January 2004 SELECTION CRITERIA: Published or unpublished randomised controlled trials of macrolide antibiotics compared to placebo, another class of antibiotic or another macrolide antibiotic. Studies comparing regimens of the same macrolide antibiotic at different doses will also be included. DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted data and assessed study quality. Three groups were contacted for missing data and we hope to include these in future reviews. MAIN RESULTS: Searches identified 14 studies, four were included in this review (296 participants). Two studies enrolled adults, one children (a significant number of whom were not colonised with Pseudomonas aeruginosa) and one both adults and children. All the clinical studies reported small but significant improvements in respiratory function with azithromycin versus placebo. Meta-analysis at the one-month and six-month time points demonstrates a significant benefit with respect to relative change in FEV1 (at six months, for n = 104, azithromycin and n = 114, placebo; WMD 5.82% (95% CI 2.45 to 9.20)). The largest study reported a significant increase in mild adverse events (nausea, diarrhoea and wheezing). REVIEWERS' CONCLUSIONS: There is clear evidence from these studies of a small but significant improvement in respiratory function following treatment with azithromycin. The largest study employed a three times a week dose and, in this study, treatment with azithromycin was associated with a significant increase in mild adverse events. Further studies are needed to clarify the precise role of azithromycin in the treatment of CF lung disease.

Macrolide antibiotics for cystic fibrosis.

BACKGROUND: The antibiotic treatment of chest infections which characterise cystic fibrosis (CF) has significantly improved prospects for people with CF. The nature of organisms causing these infections has restricted antibiotic choice. Pseudomonas aeruginosa, especially, is resistant to most oral antibiotics. There is evidence from the laboratory and from other disease processes that macrolide antibiotics, whilst not directly active against Pseudomonas aeruginosa, may have indirect actions against this organism. OBJECTIVES: We aimed to test the hypotheses that macrolide antibiotics:(1) improve clinical status compared to placebo or another antibiotic;(2) have no unacceptable adverse effects. If benefit was demonstrated, we aimed to assess the optimal type, dose and duration of macrolide therapy. SEARCH STRATEGY: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group trials register comprising references identified from comprehensive electronic database searches, handsearching relevant journals and abstract books of conference proceedings.We contacted principal investigators known to work in the field, previous authors and pharmaceutical companies who manufacture macrolide antibiotics for unpublished or follow-up data (December 2002). Date of the most recent search of the Group's register: March 2003. SELECTION CRITERIA: Published or unpublished randomised controlled trials of macrolide antibiotics compared to placebo, another class of antibiotic or another macrolide antibiotic. Studies comparing regimens of the same macrolide antibiotic at different doses will also be included. DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted data and assessed study quality. Two groups were contacted for missing data, but these were unavailable for the review. MAIN RESULTS: Searches identified eleven studies, two were included in this review (101 participants). One study enrolled adults and the other children (a significant number of whom were not colonised with Pseudomonas aeruginosa). Both studies report small but significant changes in respiratory function (% change in FEV1) in favour of azithromycin. Meta-analysis at the two-month time point demonstrated a significant benefit with respect to percentage change in FVC (weighted mean difference 5.42 (1.77 to 9.07)) from azithromycin, but no difference with respect to percentage change of FEV1. There were no significant adverse effects reported. REVIEWER'S CONCLUSIONS: The role of macrolides in the management of CF lung disease remains unclear and there are many unanswered questions. Two small randomised controlled trials have suggested short-term improvement in respiratory function with azithromycin. Until the results of further studies are available the widespread use of azithromycin in CF cannot be advocated and should be restricted to well-designed randomised controlled trials.

The presentation and management of juvenile-onset chronic inflammatory bowel disease in Northeastern Scotland.

PURPOSE: This study reviews the presentation and management of juvenile onset chronic inflammatory bowel disease and identifies changes in incidence of the disease over a 20-year period. METHODS: This was a retrospective study of all patients aged 16 and under with chronic inflammatory bowel disease diagnosed in 1 health region between 1980 and 1999. The patients were identified from computer records and the following variables studied: age, sex, mode of presentation, medical and surgical management, and length of follow-up. RESULTS: One hundred seven patients were identified: 77 with Crohn's disease and 30 with ulcerative colitis. The incidence of ulcerative colitis and Crohn's disease has risen from 0.7 in 100,000 and 2.2 in 100,000, respectively, in the years 1980 through 1989 to 1.5 in 100,000 and 4.4 in 100,000 in the period 1990 through 1999. The median age at presentation was 10.1 years for ulcerative colitis and 10.8 years for Crohn's disease. The majority of disease was diagnosed within 1 year of the onset of symptoms, which were principally abdominal pain, diarrhea, and rectal bleeding. The average length of follow-up was 6.9 years. Analysis of the surgical management of Crohn's patients has shown a low rate of surgical intervention. CONCLUSIONS: This study has shown an increasing incidence of chronic inflammatory bowel disease in the Grampian region of Scotland coupled with a low rate of surgical intervention in Crohn's disease. These findings could be the result of early referral and diagnosis, with the disease being documented earlier in its course or more aggressive preemptive medical therapy.

Airway surface liquid recovered by lavage with perfluorocarbon liquid in cats.

BACKGROUND: Airway surface liquid (ASL) is difficult to sample. Lavage with an immiscible perfluorocarbon (PFC) liquid to recover ASL was evaluated in cats. MATERIALS AND METHODS: Six wild-type cats underwent bronchoscopic lavage with a PFC (perfluorohexane), with the bronchoscope wedged in the feline equivalent of the right lower lobe. Two cats (control animals) were lavaged with a saline vehicle only. Four procedures were performed on each animal at 2-3-week intervals. Ionic composition of ASL was determined by flame photometry. RESULTS: Cats lavaged with PFC showed significantly more acute respiratory distress than those lavaged with saline (respiratory rate following procedure: PFC, 47 +/- 5 min-1 vs. saline, 27 +/- 2 min-1, P < 0.05; O2 saturation: PFC 80 +/- 1% vs. saline, 91 +/- 1%, P < 0.01). The PFC group also had clinical evidence of chronic respiratory compromise (mean respiratory rate before next anaesthetic; PFC, 37 +/- 2 min-1 vs. saline, 20 +/- 3 min-1, P < 0.01). The PFC-lavaged lungs demonstrated persistent radiographic changes and histological evidence of small airways obstruction with distal alveolar damage. Six PFC lavages yielded ASL samples (> 100 microL) which were sufficient for analysis. Mean (+/- SEM) ionic concentrations in these samples were Na+ 157.4 +/- 14.5 mmol L-1, Cl- 150.5 +/- 16.8 mmol L-1 and K+ 10.1 +/- 1.7 mmol L-1. CONCLUSIONS: Perfluorocarbon lavage can be used to collect unmodified ASL from the distal lung. However, repeated lavage with perfluorohexane was associated with significant pathological changes in this study.

Survival following Burkholderia cepacia sepsis in a patient with cystic fibrosis treated with corticosteroids.

We describe an 11-year-old girl with cystic fibrosis (CF) who presented with respiratory failure and Burkholderia cepacia bacteremia (cepacia syndrome). She survived her illness after aggressive treatment with parenteral antibiotics and corticosteroids. We speculate that treatment with corticosteroids may decrease the influx of proinflammatory cytokines and neutrophil-induced inflammation, with resulting improvement in the outcome of cepacia syndrome in CF patients.

A modified technique for measurement of nasal transepithelial potential difference in infants.

OBJECTIVE: To establish a method for measuring nasal transepithelial potential difference (PD) in infants. STUDY DESIGN: A modified infant method (smaller catheter size, reduced flow rates, and shorter protocol time) was compared with an established adult nasal PD method in 10 adult volunteers (4 with cystic fibrosis [CF]). Nasal PD was measured in 13 infants with a possible diagnosis of CF. RESULTS: Recordings were similar for the established and the modified methods in adult volunteers. An amiloride concentration of 10(-4) mol/L was necessary for full inhibition of amiloride-sensitive sodium ion (Na(+)) transport. Of the 13 infants, 2 had PD values suggestive of CF (mean baseline PD, -50.1 mV and -31.4 mV; maximum baseline PD, -61 mV and -49 mV; change in PD after perfusion with zero chloride solution with isoprenaline and amiloride [DeltazeroCl(-)/Iso], -1 mV and +3.5 mV), and 11 had normal values (mean +/- SEM baseline PD, -13.2 +/- 1.0 mV; maximum baseline PD, -21.4 +/- 2.0; DeltazeroCl(-)/Iso, -15.3 +/- 1.9 mV). These results correlated with subsequent sweat test data, mutation analysis, and clinical outcome. CONCLUSION: Nasal PD measured with this modified method is comparable to that measured with an established adult method. The measurements were well tolerated in 13 infants and discriminated bioelectric profiles characteristic of normal and CF respiratory epithelium. This study supports the use of this modified nasal PD technique as a diagnostic test for CF in newborn infants.

Liquid and ion transport by fetal airway and lung epithelia of mice deficient in sodium-potassium-2-chloride transporter.

Chloride (Cl(-)) movement across fetal lung epithelia is thought to be mediated by the sodium-potassium-2-Cl(-) cotransporter NKCC1. We studied the role of NKCC1 in Cl(-) and liquid secretion in late-gestation NKCC-null (-/-) and littermate control fetal mouse lung. NKCC -/- mice had decreased lung water compared with littermate controls (wet/dry: control, 8.01 +/- 0.09; NKCC -/-, 7.06 +/- 0.14). Liquid secretion by 17-d NKCC -/- distal lung explants was similar to control explants. Bumetanide inhibited basal liquid secretion in control but not NKCC -/- explants (expansion over 48 h: control, 35 +/- 4%; NKCC -/- 46 +/- 7%). Treatment with 4,4'-diisothiocyanto-stilbene-2,2'-disulfonic acid (DIDS) decreased liquid secretion in both control and NKCC -/- explants. Basal transepithelial potential difference (PD) of control tracheal explants was higher than that of NKCC -/- (control, -13.7 +/- 0.5 mV; NKCC -/-, -11.6 +/- 0.6 mV). Amiloride (10(-)(4) M) inhibited basal PD to the same extent in control and NKCC -/- mice. Terbutaline-stimulated hyperpolarization was less in NKCC -/- than in control tracheas (DeltaPD: control, -10.8 +/- 1.33 mV; NKCC -/-, -6.1 +/- 0.7 mV) and was inhibited by DIDS and acetazolamide in NKCC -/- but not wild-type explants. We conclude that NKCC is rate-limiting for transcellular Cl(-) transport, and that alternative anion transport mechanisms can sustain liquid production at near-normal levels in the fetal NKCC -/- mouse lung.

Macrolide antibiotics for cystic fibrosis.

BACKGROUND: Cystic Fibrosis is characterised by chest infection, the antibiotic treatment of which has significantly improved the outlook for people with this condition. The unusual nature of organisms that infect the chest of individuals with cystic fibrosis has restricted antibiotic choice. In particular the bacteria, Pseudomonas aeruginosa, is resistant to nearly all antibiotics that can be taken by mouth. There is laboratory evidence and evidence from other disease processes that macrolide antibiotics, whilst not directly active against Pseudomonas aeruginosa, may have indirect actions against this bacteria. OBJECTIVES: This review aimed to test the hypotheses that macrolide antibiotics; 1) Improve clinical status compared to placebo or another antibiotic 2) do not have unacceptable adverse effects If benefit was demonstrated, we aimed to assess the optimal type, dose and duration of macrolide therapy. SEARCH STRATEGY: We searched the Cochrane Cystic Fibrosis and Genetic Disorders Group specialist trials register which comprises references identified from comprehensive electronic database searches, handsearching relevant journals and handsearching abstract books of conference proceedings. In addition, Principal Investigators, known to work in the field and previous authors were contacted for unpublished or follow up data. Pharmaceutical companies, that manufacture macrolide antibiotics, were approached. SELECTION CRITERIA: Randomised controlled trials, published or unpublished, of macrolide compared to placebo, another class of antibiotic or another macrolide. Studies which compare regimes of the same macrolide at different doses will also be included. DATA COLLECTION AND ANALYSIS: No completed randomised controlled trials were identified. MAIN RESULTS: Three open studies excluded. Four ongoing randomised controlled trials were identified. No completed randomised controlled trials were identified. REVIEWER'S CONCLUSIONS: At present, there are no randomised controlled trials to evaluate the use of macrolide antibiotics for the treatment of chest infection in people with cystic fibrosis. Such trials, with clear outcome measures, are needed to properly evaluate this potentially useful treatment for cystic fibrosis.

Salt restriction induces pseudohypoaldosteronism type 1 in mice expressing low levels of the beta-subunit of the amiloride-sensitive epithelial sodium channel.

The amiloride-sensitive epithelial sodium channel (ENaC) is a heteromultimer of three homologous subunits (alpha-, beta-, and gamma-subunits). To study the role of the beta-subunit in vivo, we analyzed mice in which the betaENaC gene locus was disrupted. These mice showed low levels of betaENaC mRNA expression in kidney (approximately 1%), lung (approximately 1%), and colon (approximately 4%). In homozygous mutant betaENaC mice, no betaENaC protein could be detected with immunofluorescent staining. At birth, there was a small delay in lung-liquid clearance that paralleled diminished amiloride-sensitive Na+ absorption in tracheal explants. With normal salt intake, these mice showed a normal growth rate. However, in vivo, adult betaENaC m/m mice exhibited a significantly reduced ENaC activity in colon and elevated plasma aldosterone levels, suggesting hypovolemia and pseudohypoaldosteronism type 1. This phenotype was clinically silent, as betaENaC m/m mice showed no weight loss, normal plasma Na+ and K+ concentrations, normal blood pressure, and a compensated metabolic acidosis. On low-salt diets, betaENaC-mutant mice developed clinical symptoms of an acute pseudohypoaldosteronism type 1 (weight loss, hyperkalemia, and decreased blood pressure), indicating that betaENaC is required for Na+ conservation during salt deprivation.

Quantitation and localization of ENaC subunit expression in fetal, newborn, and adult mouse lung.

The newborn lung is cleared of fetal liquid by active Na+ transport. The heterotrimeric (alpha, beta, gamma) epithelial Na+ channel, ENaC, mediates this process. To understand the role of individual ENaC subunits in Na+ transport during development, we quantified murine ENaC (mENaC) subunit messenger RNA (mRNA) expression levels of fetal, neonatal, and adult mouse lung by Northern blot analysis and studied regional expression by in situ hybridization. alphamENaC and gammamENaC mRNA expression increased sharply in late fetal gestation and reached near-adult levels by Day 1 of postnatal life. betamENaC expression increased more gradually through late fetal and early postnatal life and increased progressively until adulthood. In situ hybridization studies showed similar localization patterns of alphamENaC and gammamENaC subunit expression in fetal and postnatal lung. gammamENaC and alphamENaC subunits were initially localized to fetal lung bud tubules and by late gestation both subunits were expressed in all regions (acinar and bronchiolar) of the distal lung epithelium. betamENaC was detected from 16 d gestation onward and was expressed most intensely in small airways. There was little expression of betamENaC in the alveolar region. In postnatal lung all three subunits were expressed intensely in small airways. In adult lung, alphamENaC and gammamENaC were expressed in a pattern consistent with an alveolar type II (ATII) cell distribution. The timing of quantitative changes in mENaC subunit expression is consistent with a role of Na+ transport in liquid clearance of the perinatal lung. Intense expression of mENaC subunits in medium and small airway epithelium and in ATII cells suggests that these regions are a primary location for liquid absorption in the perinatal and postnatal murine lung.

Role of gammaENaC subunit in lung liquid clearance and electrolyte balance in newborn mice. Insights into perinatal adaptation and pseudohypoaldosteronism.

Genetic evidence supports a critical role for the epithelial sodium channel (ENaC) in both clearance of fetal lung liquid at birth and total body electrolyte homeostasis. Evidence from heterologous expression systems suggests that expression of the alphaENaC subunit is essential for channel function, whereas residual channel function can be measured in the absence of beta or gamma subunits. We generated mice without gammaENaC (gammaENaC -/-) to test the role of this subunit in neonatal lung liquid clearance and total body electrolyte balance. Relative to controls, gammaENaC (-/-) pups showed low urinary [K+] and high urinary [Na+] and died between 24 and 36 h, probably from hyperkalemia (gammaENaC -/- 18.3 mEq/l, control littermates 9.7 mEq/l). Newborn gammaENaC (-/-) mice cleared lung liquid more slowly than control littermates, but lung water at 12 h (wet/dry = 5.5) was nearly normal (wet/dry = 5.3). This study suggests that gammaENaC facilitates neonatal lung liquid clearance and is critical for renal Na+ and K+ transport, and that low level Na+ transport may be sufficient for perinatal lung liquid absorption but insufficient to maintain electrolyte balance by the distal nephron. The gammaENaC (-/-) newborn exhibits a phenotype that resembles the clinical manifestations of human neonatal PHA1.

Effects of adenosine, ATP, and UTP on chloride secretion by epithelia explanted from fetal rat lung.

Catecholamines trigger the switch from liquid secretion to absorption by perinatal lung, but regulation of Cl- and liquid secretion by pulmonary epithelia early in lung development (low [catecholamine]) is unknown. We looked for evidence for P1 and P2 receptors that mediate Cl- secretion in 14-d distal lungs and 14- and 18-d tracheas explanted from fetal rats (term = 22 d). We measured amiloride-insensitive transepithelial voltage changes induced by ATP, UTP, or adenosine. Explants were hyperpolarized by all three agonists and by terbutaline, a beta-adrenergic agonist and Cl- secretagogue. Whereas adenosine, ATP, or UTP injected into 14-d explant lumena, or adenosine added to the tracheal bath, induced hyperpolarization with EC50 of 2-15 microM EC50, values for all three agonists in the distal lung bath or ATP or UTP in the tracheal bath were five times greater. By 18 d, EC50 values for agonists in the bath were comparable to those for lumenal agonists (3-12 microM). In contrast, microinjection of terbutaline into all explant lumena (final concentration = 3 x 10(-5) M) induced minimal hyperpolarization, whereas the same concentration in the bath raised bioelectric potential difference maximally. We conclude that 1) beta-adrenergic receptors are present on the basolateral membranes of cells of the pulmonary epithelium early in lung development, and 2) adenosine, ATP, and UTP receptors are present in apical membranes throughout lung epithelial development, but basolateral receptors for these agonists in distal lung or ATP/UTP in trachea function later in gestation. The putative distribution of P1 and P2 receptors suggests a role for agonists released from pulmonary epithelial cells in the regulation of liquid secretion early in lung development.

Decreased sodium ion absorption across nasal epithelium of very premature infants with respiratory distress syndrome.

OBJECTIVE AND STUDY DESIGN: Successful adaptation to air breathing at birth depends on rapid absorption of fetal lung liquid that is mediated by activation of amiloride-sensitive sodium ion channels. To test the relationship between respiratory epithelial Na+ transport and development of respiratory distress syndrome (RDS), we measured nasal transepithelial potential difference (PD) in 31 very premature (< or = 30 weeks of gestation) newborn infants. Infants were retrospectively assigned to RDS (22 infants) and non-RDS (9 infants) groups on the basis of clinical and chest x-ray criteria. RESULTS: Maximal nasal epithelial PD increased with birth weight (-1.2 mV/100 gm) and was lower in infants with RDS (-16.5 +/- 0.6 mV) than in those without RDS (-22.0 +/- 1.3 mV). Infants without RDS had PD values similar to normal fullterm infants. Amiloride inhibition of PD, an index of Na+ absorption, was significantly lower, within the first 24 hours of life, in infants in whom RDS developed (3.8 +/- 0.2 mV; 29.5% +/- 0.8% inhibition) than in those without RDS (6.1 +/- 0.6 mV; 38.6% +/- 0.5% inhibition). Maximal and amiloride-sensitive PD returned to normal during the recovery phase of RDS. CONCLUSIONS: We conclude that Na+ absorption across nasal epithelium increases with increasing birth weight and that impairment of Na+ absorption across the respiratory epithelia of very premature infants may contribute to the pathogenesis of RDS.

Efficient adenovirus-mediated gene transfer to basal but not columnar cells of cartilaginous airway epithelia.

Adenoviral vectors (AdV) developed for treatment of the pulmonary manifestations of cystic fibrosis (CF) can deliver, with high efficiency, transgenes to respiratory epithelial cells grown in culture. This study investigated the efficiency of AdV-mediated gene transfer to murine and human respiratory epithelium in vivo and concluded that the epithelial cells facing the lumen of the respiratory cartilaginous airways (columnar cells) are poorly transduced with AdV. Mechanical injury to the epithelium, however, leads to efficient in vivo gene transfer by exposing a susceptible epithelial subtype (basal cells). Increased gene transfer efficiency in vivo after injury is not a nonspecific response because the proliferative status of the epithelium after injury was shown not to correlate temporally to the increased transduction susceptibility of the epithelium. Although basal cells were the cell type transduced at the time of vector delivery, with time, basal cell differentiation to columnar cells occurred with maintenance of transgene expression. Collectively, these results show that murine and human cartilaginous airways are poorly transduced by AdV. To correct the cartilaginous airway CF bioelectrical defect in vivo, efforts should be directed to increase the tropism of AdV to the columnar airway epithelial cells.

Cl- secretion by trachea of CFTR (+/-) and (-/-) fetal mouse.

The absence of pathologic changes in newborn cystic fibrosis (CF) lung suggests that the fetal CF lung is inflated with a normal volume of liquid and that Cl- is secreted through paths other than the cystic fibrosis transmembrane conductance regulator (CFTR)-associated Cl- channel. We studied liquid content of distal lung and transepithelial electrical potential difference (PD) of cultured cystic tracheal explants from 16 to 19 day gestation fetal mice of CFTR (+/-)(heterozygous) females that were mated with CFTR (-/-) "knockout" males. Distal lung water content was not affected by fetal genotype. Basal PDs were not different (CFTR (+/-), 8.6 mV, and CFTR (-/-), 9.1 mV), and PDs of both groups were inhibited by intraluminal injection of amiloride (10(-4) M) (-25%) and after addition of bumetanide (10(-4) M) to the bath (-40%). Terbutaline (3 x 10(-5) M) induced a similar increase in PD (about 65%) in both groups. Intraluminal injection of ionomycin (2 x 10(-5) and 5 x 10(-6) M) raised PD in both groups (CFTR (+/-) by 32 and 27% and CFTR (-/-) by 41 and 11%). All of the increase in PD induced by terbutaline and ionomycin was inhibited by bumetanide. The PD response to terbutaline was not attenuated by pretreatment with ionomycin or the Ca2+ chelator BAPTA (10(-4) M). Ionomycin or ATP, but not terbutaline, increased intracellular Ca2+ concentration of isolated cultured tracheal epithelial cells.(ABSTRACT TRUNCATED AT 250 WORDS)