Distinct spectrum of CFTR gene mutations in congenital absence of vas deferens

Congenital absence of the vas deferens (CAVD) is a frequent cause for obstructive azoospermia and accounts for 1%-2% of male infertility. A high incidence of mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) gene has recently been reported in males with CAVD. We have investigated a cohort of 106 German patients with congenital bilateral or unilateral absence of the vas deferens for mutations in the coding region, flanking intron regions and promotor sequences of the CFTR gene. Of the CAVD patients, 75% carried CFTR mutations or disease-associated CFTR variants, such as the "5T" allele, on both chromosomes. The distribution of mutation genotypes clearly differed from that observed in cystic fibrosis. None of the CAVD patients was homozygous for delta F508 and none was compound heterozygous for delta F508 and a nonsense or frameshift mutation. Instead, homozygosity was found for a few mild missense or splicing mutations, and the majority of CAVD mutations were missense substitutions. Twenty-one German CAVD patients were compound heterozygous for delta F508 and R117H, which was the most frequent CAVD genotype in our study group. Haplotype analysis indicated a common origin for R117H in our population, whereas another frequent CAVD mutation, viz. the "5T allele" was a recurrent mutation on different intragenic haplotypes and multiple ethnic backgrounds. We identified a total of 46 different mutations and variants, of which 15 mutations have not previously been reported. Thirteen novel missense mutations and one unique amino-acid insertion may be confined to the CAVD phenotype. A few splice or missense variants, such as F508C or 1716 G-->A, are proposed here as possible candidate CAVD mutations with an apparently reduced penetrance. Clinical examination of patients with CFTR mutations on both chromosomes revealed elevated sweat chloride concentrations and discrete symptoms of respiratory disease in a subset of patients. Thus, our collaborative study shows that CAVD without renal malformation is a primary genital form of cystic fibrosis in the vast majority of German patients and links the particular expression of clinical symptoms in CAVD with a distinct subset of CFTR mutation genotypes.

Decreased concentration of exhaled nitric oxide (NO) in patients with cystic fibrosis

Nitric oxide (NO) is produced by various cell types in the human respiratory tract. Endogenously produced nitric oxide is detectable in the exhaled air of healthy individuals. Exhaled NO has been shown to be increased in airway inflammation, most probably due to cytokine-mediated activation of NO synthases. To assess whether NO can serve as a marker of inflammation in cystic fibrosis (CF) lung disease, we measured exhaled NO in CF patients with a chemiluminescence analyser. Single breath measurements were performed in 27 stable CF patients (age range, 6-40 years) and 30 non-smoking controls (age range, 6-37 years). Exhaled NO concentrations were 9.1 +/- 3.6 ppb in the controls and 5.9 +/- 2.6 ppb (P < 0.001) in CF patients. To account for room air NO concentrations on the measurement of exhaled NO, we also calculated the difference between exhaled NO and ambient NO concentrations. Difference values were also significantly lower in CF compared with controls (P < 0.0001). In CF patients there was a positive correlation between exhaled NO and forced vital capacity (r = 0.43, P = 0.033), suggesting that exhaled NO is lower in patients with severe lung disease than in those with mild disease. We conclude that measurements of exhaled NO in CF does not reflect activity of CF airway inflammation. The decreased concentrations of exhaled NO may be due to inhibitory effects of inflammatory cytokines on NO syntheses in the airways and alveolar epithelial cells or to increased retention in airway secretions.

Metabolites of nitric oxide in the lower respiratory tract of children

Nitric oxide (NO) is produced in the upper and lower respiratory tract and can be detected in exhaled air of both healthy individuals and subjects with pulmonary diseases. Recent studies have shown that exhaled NO is mainly derived from the upper airways. There is, however, evidence that in aqueous solutions NO is rapidly converted to distinct oxides of nitrogen. We therefore studied the stable NO metabolites nitrate and nitrite in broncho-alveolar lavage (BAL) fluid and serum as indicators of NO formation in the lower respiratory tract. The study population consisted of 31 healthy children undergoing elective surgery for non-pulmonary illnesses and 13 immunosuppressed children with pneumonia. Nitrate and nitrite were determined photometrically. Nitrate was found in BAL fluid of all children. In children with pneumonia, nitrate concentrations in BAL fluid were significantly higher than in healthy children. A significant correlation was observed between nitrate in BAL fluid and serum of immunosuppressed children with pneumonia. Nitrite was not detected in any of the BAL fluid or serum samples.

CONCLUSIONS

Our results suggest that in the lower airways significant amounts of NO are metabolised to nitrate. Studies on NO in pulmonary diseases should therefore include determination of nitrate in lower airway fluids.

Genetic diversity among isolates of Aspergillus fumigatus in patients with cystic fibrosis

Strains of Aspergillus fumigatus (n = 24) were isolated from the sputa of six patients with cystic fibrosis during periods from 3 to 11 months. The genetic polymorphisms of the strains were studied using the random amplified polymorphic DNA (RAPD) assay with three single oligonucleotides and pairwise combined primers. The analysis of RAPD patterns resulted in 15 different RAPD types. In four patients, the colonizing type changed, whereas in two others the same types were detected over periods between 3 and 11 months. The genetic diversity as well as the shift of the colonizing strains found in some patients might be important for the epidemiology of Aspergillus infections in patients with cystic fibrosis.

[Bronchoalveolar lavage in childhood: technical aspects and reference values]

(BAL) has been increasingly used in recent years also in children. In paediatric pulmonary diseases, however, interpretation has proved difficult in the absence of standard reference values for BAL in childhood. It is the purpose of the present publication to discuss the methodological aspects of BAL in childhood and to proviced criteria by means of standard reference values for the assessment of BAL in paediatric patients. In a group of 50 children aged 3 to 15 years with healthy lungs, who were subjected to BAL during an elective surgical intervention, we examined both cellular and non-cellular components of the BAL. Whereas the percentage of macrophages and lymphocytes in the total population did not differ significantly from the standard values in adults, the absolute and relative granulocyte count was found to be elevated in children under 8 years of age. The CD4/CD8 quotient of BAL was 0.7 on the average, and hence clearly below the standard reference values defined for adults. In the non-cellular components we found an increase in the level of all proteins from plasma, whereas locally produced proteins did not differ from the findings in healthy adults. The total phospholipid content of BAL was markedly enhanced in children below 8 years of age and decreased with increasing age. These differences between children and adults should be taken into account when interpreting pathological findings. They are the basis for better defining the ranking of BAL in paediatric pulmonary diseases.

Immunoglobulin and beta 2-microglobulin concentrations in bronchoalveolar lavage of children and adults

Immunoglobulins play an important role in the pulmonary host defense, but little information is available about immunoglobulin and beta 2-microglobulin concentrations in the lung of normal children. Using bronchoalveolar lavage (BAL) we have studied immunoglobulin and beta 2-microglobulin levels in 30 children 3-15 years old undergoing elective surgery for nonpulmonary illnesses and in 15 healthy adult volunteers. BAL was performed with 3 x 1 ml/kg of body weight normal saline through an endotracheal tube after induction of anesthesia in children and under local anesthesia in adults. Similar concentrations of IgA and IgG were found in BAL fluid of children and adults even though serum levels were lower in children. As comparable results were obtained for albumin, a serum-derived protein, these data suggest that the permeability of the alveolar membrane is higher in children. IgE and IgM were detected in BAL fluid in only a fraction of children. beta 2-microglobulin levels were higher in both blood and BAL fluid of children. These data provide the first reference data for immunoglobulin and beta 2-microglobulin in children and can serve as a basis for future studies of children with pulmonary diseases.

Differential cytology of bronchoalveolar lavage fluid in immunosuppressed children with pulmonary infiltrates

OBJECTIVE

Bronchoalveolar lavage (BAL) is a well established technique for the detection of pathogens in immunosuppressed children, but its diagnostic yield is variable. The aim of this study was to investigate whether BAL differential cell counts are helpful in the evaluation of pulmonary infiltrates in immunocompromised children.

STUDY DESIGN

BAL was performed 28 times in 27 febrile immunocompromised children with pulmonary infiltrates. All patients were pretreated with broad spectrum antibiotics; 11 children also received amphotericin B. BAL was conducted with a flexible bronchoscope wedged in the area of maximal pathology as suggested by the chest radiograph or in the middle lobe in patients with diffuse interstitial radiographic changes. Differential cell counts were performed from cell smears obtained after centrifugation of BAL fluid.

RESULTS

Bacterial or fungal organisms were detected in BAL fluid of 12 patients. Patients with bacterial or fungal infections (group 1) had a significantly higher percentage of granulocytes in BAL fluid both compared with patients with sterile BAL cultures (group 2) and with a control group of children without pulmonary disease (p < 0.001, Wilcoxon test). The proportion of lymphocytes was not different from the control group in group 1 but significantly increased in group 2 (p < 0.001, Wilcoxon test). Blood differential cell counts were not different in the two patient groups. Lymphocyte subsets of BAL fluid obtained in a subgroup of patients were not significantly different from controls.

CONCLUSION

These data suggest that BAL differential cell counts may be a useful adjunct in the differential diagnosis of pulmonary infection in immunocompromised children.

Adjustment of bronchoalveolar lavage volume to body weight in children

To define the amount of epithelial lining fluid (ELF) that is recovered during bronchoalveolar lavage (BAL) in the pediatric age group, we measured albumin and urea concentrations in serum and BAL fluid (BALF) of 37 children aged 3-15 years without bronchopulmonary disease. The children were studied while undergoing elective surgery for non-pulmonary illnesses using a BAL protocol adjusted to body weight. ELF increased with age in proportion to increases in lavage volume. When corrected for the child's weight, approximately 20 mu l ELF/kg body weight were recovered throughout the age range. ELF derived by determining albumin or urea concentrations in BALF were significantly correlated; however, considerable variability was observed in older children when the urea method was used. This was likely due to the increase in dwell time that is known to affect urea concentrations in BALF. In children ELF/100 ml BALF was higher than in adults, suggesting a greater permeability of the alveolar membrane in children. These data show that a BAL protocol adjusted to body weight will yield constant fractions of ELF in children aged 3-15 years. These results should facilitate the comparison of BALF constituents in children of different age groups.

Age-dependency of surfactant phospholipids and surfactant protein A in bronchoalveolar lavage fluid of children without bronchopulmonary disease

Whilst alterations in surfactant components of bronchoalveolar lavage fluid (BALF) have been described in a variety of pulmonary diseases in adults, no information is available on the surfactant composition in children beyond the neonatal period. In order to obtain reference values for the paediatric age group, we have studied phospholipid profiles of BALF in children without pulmonary disease. The study population consisted of 38 children aged 3-15 yrs (mean +/- SD 8 +/- 4 yrs) undergoing elective surgery for nonpulmonary illnesses. Surfactant composition was analysed by high pressure liquid chromatography using both an ultraviolet and a light-scattering detector. Total phospholipid concentration was higher in children under 8 yrs of age and decreased with age. In contrast, the total protein concentration remained constant throughout the age range. No age-related changes in the relative composition of phospholipid fractions could be observed. Surfactant protein A concentrations were highly variable in all age groups. This study provides the first data on surfactant components in bronchoalveolar lavage fluid of healthy children and will be the basis for future studies of children with pulmonary diseases.

The effect of rapid thoracoabdominal compressions on intracranial pressure in newborn lambs

Measurements of forced expiratory flow in infants can be obtained with the rapid thoracoabdominal compression (RTC) technique. To assess the transmission of the chest wall compression pressure into the cerebrum, we have performed intracranial pressure (ICP) measurements during RTCs in newborn lambs. Thirteen lambs were studied during the first 8 d of life. An epidural pressure transducer was implanted under general anesthesia. Respiratory measurements were performed under sedation with ketamine. RTCs were induced through an inflatable jacket wrapped around the lamb's trunk. RTCs were started with a pressure of 30 cm H2O. The compression pressure was increased in steps of 20 cm H2O up to 250 cm H2O. Flow and volume were determined with a pneumotachograph attached to a face mask. Transpulmonary pressure (Ptp) was measured with an esophageal balloon placed in the lower esophagus. RTCs resulted in proportional increases of Ptp and ICP. ICP was lower or equal to Ptp in all measurements. No changes in baseline ICP occurred throughout the study period. The maximal ICP observed during RTCs was within the range of pressures observed during crying in newborn infants. These data suggest that the RTC technique can be considered safe even at high compression pressures.

[The importance of lung function as a predictor of 2-year mortality in mucoviscidosis]

Prediction of mortality in cystic fibrosis (CF) has become an important issue in the era of lung transplantation. A study from Toronto has shown a forced expiratory volume in one second (FEV1) below 30% predicted to be the best predictor of two-year mortality. The purpose of this investigation was to assess whether these data are relevant for other CF centers with a different overall life expectancy. We have analysed pulmonary function tests (PFTs) obtained in our population of CF patients between 1979 and 1991. 19 of the 73 patients included in this analysis had died. Cox proportional hazard regression analysis was performed using the lung function parameters as single covariates. In addition results of PFTs obtained two years before death were compared to similarly lagged values of surviving patients. Inspiratory vital capacity (IVC) (p < 0.0001), the ratio of residual volume/total lung capacity (RV/TLC) (p < 0.0001), forced expiratory volume in one second (FEV1) (p < 0.0002), specific conductance (sGaw) (p < 0.025) and a weight for height below the third percentile (p < 0.023) were significant predictors of two-year mortality. Two-year mortality were 50% for a FEV1 < 30% predicted and 47% for a RV/TLC ratio > 50%. Our data confirm that a FEV1 < 30% and a RV/TLC ratio > 50% are significant predictors of mortality in CF. However, interindividual variability in survival with a FEV1 < 30% is high. The decision for lung transplantation can therefore not be based on pulmonary function alone.

Lymphocyte subsets in bronchoalveolar lavage fluid of children without bronchopulmonary disease

Bronchoalveolar lavage (BAL) is increasingly used in the pediatric age group. However, normal values for BAL fluid (BALF) constituents are lacking. As part of an investigation to define reference values in children, we studied lymphocyte surface markers of BALF in 28 children 3 to 16 yr of age without bronchopulmonary disease. All of them were undergoing elective surgery for nonpulmonary illnesses. BAL was performed under general anaesthesia with tracheal intubation. A flexible bronchoscope (Pentax 3.5 or 4.9 mm) was wedged into the middle lobe or into one of its segments, and 3 x 1 ml/kg body weight normal saline warmed to body temperature were instilled and immediately withdrawn. The first sample was studied separately; subsequent samples were pooled for analysis. Studies on lymphocyte surface markers were performed on the pooled sample only. The distribution of B-cells, pan T-cells, and CD57 positive cells was within the range reported for adult subjects. However, CD4/CD8 ratios were lower than in adults (0.7 +/- 0.4, mean +/- SD). This decrease in the CD4/CD8 ratio was caused by an increase in CD8 cells. Comparative analysis of blood and BALF lymphocytes in a subgroup of children showed that CD4/CD8 ratios in blood were within the normal range reported for this age group and significantly higher when compared with BALF. The lower CD4/CD8 ratios in normal children have to be considered in the interpretation of BALF in children with pulmonary diseases.

Differential cytology of bronchoalveolar lavage fluid in normal children

Bronchoalveolar lavage (BAL) is increasingly used in the assessment of pulmonary diseases in children. However, reference values for cellular and non-cellular constituents of BAL fluid in children are lacking. We have studied the differential cytology of BAL fluid in 48 children aged 3-16 years (mean age +/- SD 7.9 +/- 3.5 yrs) undergoing elective surgery for nonpulmonary illnesses. A flexible bronchoscope (Pentax 3.5 or 4.9 mm) was wedged in the middle lobe or one of its segments. BAL was performed with 3x1 ml-kg-1 body weight of normal saline warmed to body temperature. The first sample was studied separately; subsequent samples were pooled for analysis. The mean recovery was 58 +/- 15%. Significantly more granulocytes and less lymphocytes were found in the first, as compared to the pooled, sample. Total cell counts were highly variable and ranged from 0.5-57.1 x 10(4) ml-1. Macrophages were the predominant cell type, with a mean percentage of 81.2 +/- 12.7%. The relative proportion of lymphocytes was higher than that reported in most studies of adult volunteers (16.1 +/- 2.4%). No age dependency was observed for either cell type. The mean percentage of granulocytes was 2.5 +/- 3.3%. Absolute granulocyte counts were significantly higher in children under 8 yrs of age. This study provides the first reference data on BAL differential cytology in children without pulmonary disease and will be the basis for future investigations of BAL in paediatric lung diseases.

A new technique to demonstrate flow limitation in partial expiratory flow-volume curves in infants

Partial expiratory flow-volume (PEFV) curves in infants are generated by applying a compressive pressure over the chest wall with an inflatable jacket. This study addresses two issues: pressure transmission to and across the chest wall and whether flow limitation can be identified. Eleven infants sedated with chloral hydrate were studied. Pressure transmission to the chest wall, measured with neonatal blood pressure cuffs placed on the infant's body surface, was 72 +/- 4% of jacket pressure during compression maneuvers. The pressure transmission to the air spaces, determined by measuring airway pressure during a compression maneuver against an occluded airway, was 56 +/- 6% of jacket pressure. A significant amount of the applied pressure is therefore lost across both the jacket and chest wall. Rapid pressure oscillations (RPO) were superimposed on static jacket pressures while expiratory flow was measured. Absence of associated oscillations of flow measured at the mouth was taken to indicate that flow was independent of driving pressure and therefore limited. Flow limitation was demonstrable with the RPO technique in all infants for jacket pressures greater than 50 cmH2O; however, it was evident at jacket pressures less than 30 cmH2O jacket pressure in four infants with obstructive airway disease. The RPO technique is a useful adjunct to the compression maneuver utilized to generate PEFV curves in infants because it facilitates the recognition of expiratory flow limitation.

Effect of changes in lung volume on respiratory system compliance in newborn infants

Total respiratory system compliance (Crs) at volumes above the tidal volume (VT) was studied by use of the expiratory volume clamping (EVC) technique in 10 healthy sleeping unsedated newborn infants. Flow was measured with a pneumotachograph attached to a face mask and integrated to yield volume. Volume changes were confirmed by respiratory inductance plethysmography. Crs measured by EVC was compared with Crs during tidal breathing determined by the passive flow-volume (PFV) technique. Volume increases of approximately 75% VT were achieved with three to eight inspiratory efforts during expiratory occlusions. Crs above VT was consistently greater than during tidal breathing (P less than 0.0005). This increase in Crs likely reflects recruitment of lung units that are closed or atelectatic in the VT range. Within the VT range, Crs measured by PFV was compared with that obtained by the multiple-occlusion method (MO). PFV yielded greater values of Crs than MO (P less than 0.01). This may be due to braking of expiratory airflow after the release of an occlusion or nonlinearity of Crs. Thus both volume recruitment and airflow retardation may affect the measurement of Crs in unsedated newborn infants.

A double-blind placebo controlled trial with oral ambroxol and N-acetylcysteine for mucolytic treatment in cystic fibrosis

The therapeutic efficacy of oral N-acetylcysteine (NAC) and ambroxol as compared with the effect of placebos was studied in 36 cystic fibrosis (CF) patients with mild to moderate pulmonary disease. The patients were randomly assigned to one of three regimens, matched on the basis of age and Chrispin-Norman scores. The trial was conducted over a period of 12 weeks. Patients were assessed clinically and by extensive pulmonary function techniques (body-plethysmography, maximal expiratory flow-volume curves, trapped air determination). Although no clinical differences could be observed between the three groups, significant impairment in the placebo group was found for trapped air and FEV1 when compared to the active groups, suggesting a therapeutic effect of ambroxol and NAC in CF.