Similar levels of mRNA from the W1282X and the delta F508 cystic fibrosis alleles, in nasal epithelial cells.

The effect of nonsense mutations on mRNA levels is variable. The levels of some mRNAs are not affected and truncated proteins are produced, while the levels of others are severely decreased and null phenotypes are observed. The effect on mRNA levels is important for the understanding of phenotype-genotype association. Cystic fibrosis (CF) is a lethal autosomal recessive disease with variable clinical presentation. Recently, two CF patients with mild pulmonary disease carrying nonsense mutations (R553X, W1316X) were found to have severe deficiency of mRNA. In the Jewish Ashkenazi CF patient population, 60% of the chromosomes carry a nonsense mutation, W1282X. Patients homozygous for this mutation have severe disease presentation with variable pulmonary disease. The presence of CF transcripts in a group of patients homozygous and heterozygous for this mutation was studied by reverse transcriptase PCR of various regions of the gene. Subsequent hybridization to specific CF PCR probes and densitometry analysis indicated that the CF mRNA levels in patients homozygous for the W1282X mutation are not significantly decreased by the mutation. mRNA levels were compared for patients heterozygous for the W1282X mutation. The relative levels of mRNA with the W1282X, and the delta F508 or the normal alleles, were similar in each patient. These results indicate that the severe clinical phenotype of patients carrying the W1282X mutation is not due to a severe deficiency of mRNA. In addition, the severity, progression, and variability of the pulmonary disease are affected by other, as yet unknown factors.

Cough capacity in patients with muscular dystrophy.

Cough capacity was evaluated in 22 patients with muscular dystrophy (MD) using subjective cough assessment, cough flow-volume curves, maximum expiratory pressures (MEP), forced vital capacity (FVC), and peak expiratory flow rates (PEFR). In ten of the 22 patients transients of peak flow were generated during cough flow-volume maneuvers, indicating dynamic compression of the airways, which is considered important in the physiology of an efficient cough. Patients who could not generate peak flow transients had significantly reduced PEFR, FVC, and MEP values. Measurement of MEP was the most sensitive predictor of flow transient production during coughing; all of the patients who exhibited transients had MEP values of above 60 cmH2O, whereas the highest value of MEP recorded in patients without transients was 45 cmH2O. Three of the 12 patients who were unable to generate flow transients were considered to have an adequate cough by subjective assessment. We concluded that the measurement of MEP is extremely useful for assessment of cough strength in patients with MD.

Assessment of maximal expiratory pressure in healthy adults.

Maximal static expiratory pressure developed at the mouth (PEmax) provides a useful clinical index of expiratory muscle function; however, the range of normal values among laboratories shows considerable variation. We examined the hypothesis that the wide variability could be attributable to the differences in technique among laboratories. We measured PEmax at functional residual capacity (PEmax FRC) in 28 healthy subjects using the following five techniques: 1) using a scuba-type mouthpiece with the cheeks supported by the hands ("hands on"), 2) without supporting the cheeks ("no hands"), 3) using a rigid, circular mouthpiece (2.8 cm ID, "tube"), 4) using the scuba-type mouthpiece but with the cheeks supported by an observer ("other hands"), and 5) using a large-bore circular mouthpiece (4.1 cm ID, "new tube"). Mean PEmax FRC obtained with hands on was significantly higher than no-hands and tube methods. PEmax FRC values obtained by the other-hands and new-tube maneuvers were similar to the hands-on maneuver. We conclude that the technique used to measure PEmax FRC can significantly affect the results and suggest that it should be measured using a large-bore circular mouthpiece or a scuba-diving mouthpiece with the cheeks supported.

Normal activity of metabolic pathways involved in the formation and utilization of phosphoribosylpyrophosphate in erythrocytes of patients with primary metabolic gout.

The activity of metabolic pathways involved in the formation and utilization of phosphoribosylpyrophosphate (PRPP) was studied in. The erythrocytes of 34 patients with idiopathic metabolic gout. The activities of the oxidative pentose shunt, of the hypoxanthine-guanine and adenine phosphoribosyltransferases (HGPRT, APRT) and of PRPP synthetase, as well as the rates of PRPP generation and of adenine incorporation into nucleotides were found to be normal in the erythrocytes of all these patients. Four patients with metabolic gout due to enzymatic abnormalities, two relatives with partial deficiency of HGPRT and two relatives with mutant feedback-resistant PRPP synthetase, were studied for comparison. The significance of the results is discussed in relation to postulated mechanisms for purine overproduction in metabolic gout.

The critical first six months in cystic fibrosis: a syndrome of severe bronchiolitis.

The syndrome of infantile bronchiolitis in cystic fibrosis (CF) carries a high mortality. Fifteen cases of CF encountered over the past 19 years with severe bronchiolitis with onset during the first 6 months of life are described. Treatment include steroids in high doses. All patients recovered. Further progress resembled the usual natural course of CF and showed no evidence of persisting lung damage. The mechanism of this syndrome is not clear and is probably dependent on many factors involved in early lung disease in CF. The frequency of severe bronchiolitis in cystic fibrosis may not be high, but it continues to be seen in clinical practice today.

Hypercapnia in relation to pulmonary function in Duchenne muscular dystrophy.

Arterialized blood gases were analyzed in 143 patients with Duchenne muscular dystrophy (DMD) to assess the relationship between forced vital capacity (FVC) and hypercapnia. The majority of patients studied had PaCO2 values in the low or normal range. Only six older patients had hypercapnia (PaCO2 greater than or equal to 45 mm Hg), and all these patients had FVC values less than or equal to 40% predicted. We conclude that hypercapnic respiratory failure occurs as a late preterminal event in DMD.

Forced vital capacity and maximal respiratory pressures in patients with mild and moderate scoliosis.

Lung function and maximal respiratory pressures of 24 adolescent females with mild-to-moderate idiopathic scoliosis (spinal curvature 10-60 degrees) were determined and compared with 38 age- and sex-matched controls. Twelve patients with moderate scoliosis (Cobb angle 35-60 degrees) had significantly reduced mean values for FVC (% predicted) and maximal inspiratory pressure (MIP), as compared to the controls. Twelve patients with mild scoliosis (Cobb angle less than 35 degrees) had normal mean values for FVC and maximal respiratory pressures, but five individual patients had FVC values less than 80% predicted. All but one of the patients with mild scoliosis had normal MIP values. FVC (% predicted) was significantly correlated with the degree of spinal curvature (r = -0.466; P less than 0.05) but was not related to MIP. These results indicate that reduced FVC values do occur in patients with mild-to-moderate idiopathic scoliosis and suggest that these low FVC values can be attributed to the rib cage deformity rather than to an inability to generate adequate inspiratory pressures.

Normal values of maximal inspiratory and expiratory pressures with a portable apparatus in children, adolescents, and young adults.

Maximal inspiratory and expiratory mouth pressures (Plmax and PEmax) were measured over a wide age range using a cylindrical mouthpiece and a multiple trial procedure. Two hundred forty-three students and 30 adults were studied. In addition, a comparison of a cylindrical and a scuba-type mouthpiece was made in 16 subjects. Fifty percent of the subjects required five or more trials to achieve their maximal mouth pressures. Higher PEmax values were obtained using a cylindrical mouthpiece than with a scuba-type mouthpiece in 15 of the 16 subjects tested. Plmax was not affected by mouthpiece type. Males had higher Plmax and PEmax values than females except in the 8-10 years age group. Maximal mouth pressures correlated with age in boys only. Technical considerations, such as the number of trials and the type of mouthpiece used, are important determinants of maximal mouth pressure values.

The significance of sweat Cl/Na ratio in patients with borderline sweat test.

Recently a few cystic fibrosis (CF) patients with borderline or normal sweat tests have been reported. These patients present a diagnostic challenge. We aimed to study the sweat Cl/Na ratio in cystic fibrosis patients and to assess whether this ratio could be used as a diagnostic criteria. The mean sweat Cl/Na ratio of 3 groups was compared: Group A: 71 CF patients carrying 2 mutations known to be associated with severe disease presentation (delta F508, W1282X, G542X, N1303K, 1717-1G --> A). Group B: 10 compound heterozygous patients who carry one mutation associated with mild clinical disease (3849 + 10 kb --> T). Group C: 142 normal subjects. Sweat chloride levels higher than those of sodium were found in 96% of patients in Group A as compared to 3% of patients in Group C. In Group B 40% of the patients had sweat chloride levels higher than or equal to sodium levels. The mean Cl/Na ratio of Group A (1.2 +/- 0.1) differed significantly from that of Group B (0.94 +/- 0.1) and both groups had significant higher mean Cl/Na ratio compared to Group C (0.7 +/- 0.4) (P < 0.001). Thus in individuals with a borderline sweat test and a Cl/Na ratio > or = 1 the diagnosis of CF should be considered. However, a Cl/Na ratio < 1 does not exclude CF, since patients carrying mild mutations may have sweat sodium levels higher than those of chloride. Our findings suggest that the sweat Cl/Na ratio in CF is genetically determined and it may be of help in establishing the diagnosis of CF in patients with a borderline sweat test.

Serum lipase levels as a diagnostic marker in cystic fibrosis patients with normal or borderline sweat tests.

Patients with normal or borderline sweat test present a diagnostic challenge. In spite of the availability of different methods such as genetic analysis and measurements of nasal potential difference, uncertainty in diagnosing cystic fibrosis (CF) in some patients still exists. Neonates with CF have high serum lipase levels, which decline over time in pancreatic-insufficient patients, whereas pancreatic-sufficient patients demonstrate high serum lipase levels beyond infancy. Because patients with borderline or normal sweat test are almost always pancreatic sufficient, this study was aimed to assess whether serum lipase levels may be of help in establishing the diagnosis of CF in these patients. Serum lipase levels were measured in 100 CF patients and in 17 healthy individuals. Patients were grouped according to their genotype. Group A patients (n = 70) carried two mutations previously found to be associated with a pathologic sweat test and pancreatic insufficiency (delta F508, W1282X, G542X, N1303K, S549R). Group B (n = 30) were compound heterozygote patients who carried one mutation known to cause mild disease with borderline or normal sweat tests and pancreatic sufficiency (3849+10kb C-->T, 5T). Group C included 17 healthy controls. Serum lipase levels ranged between 2 and 104.4 U/L (mean +/- SD 16.9 +/- 14.7), 6.1-200 U/L (mean +/- SD 53.9 +/- 47.9), and 8.5-27.8 U/L (mean +/- SD 16.9 +/- 5.1) in Groups A, B, and C, respectively, with some overlapping between groups. The distribution of lipase levels was significantly different in Group B vs Groups A and C (P < 0.01). High lipase levels were found in 63.3% (19/30) of Group B patients, but in only 4.3% (3/70) and 0% (0/17) of Group A and C, respectively. Lipase levels were found to be inversely related to sweat chloride concentrations (r = -0.19, P < 0.05). Patients with borderline or normal sweat tests had high lipase levels, whereas low lipase levels were associated with pathologic sweat tests. Our findings indicate that the serum lipase level is genetically determined and that it has a useful role in the diagnosis of CF. Thus, in patients with borderline sweat tests and high lipase levels, the diagnosis of CF should be considered.

Systemic inflammatory mediators and cystic fibrosis genotype.

Morbidity and mortality in cystic fibrosis patients is mainly attributed to pulmonary infection and inflammation. Chemokines play a pivotal role in the inflammatory process. Although genotype-phenotype correlation in cystic fibrosis patients has been defined, a clear relationship between the defect in the cystic fibrosis transmembrane regulator (CFTR) gene and pulmonary inflammation has not been established. The aim of this study was to assess whether serum chemokines levels in cystic fibrosis patients correlate with genotype and pulmonary function tests, as well as with other clinical characteristics. Serum levels of interleukin-8, RANTES, and monocyte chemoattractant protein-1 were measured in 36 cystic fibrosis patients grouped according to their genotype. Group A included 25 patients who carried two mutations associated with a pathological sweat test and pancreatic insufficiency (deltaF508, W1282X, G542X, N1303K, S549R). Group B included 11 compound heterozygote patients who carried one mutation known to cause mild disease with borderline or normal sweat test and pancreatic sufficiency (3849+10kb C to T, 5T). Associations between chemokine levels, genotype, pulmonary function, Pseudomonas aeruginosa colonization, age, sweat chloride level, and pancreatic and nutritional status were examined. Mean interleukin-8 and monocyte chemoattractant protein-1 levels were significantly higher in group A than group B (11.4 +/- 2.1 pg/ml vs. 5 +/- 0.9 pg/ml and 157 +/- 16 pg/ml vs. 88.8 +/- 16.4 pg/ml, respectively) (P < 0.01). No difference in RANTES levels were found between groups. interleukin-8 levels were inversely related to forced expiratory volume in 1 s (r = -0.37, P < 0.02), while there was no association between the latter and RANTES and monocyte chemoattractant protein-1 levels. The Pseudomonas colonization rate was higher among group A patients than group B (88% vs. 40%, P < 0.01). No relationship was found between measured chemokines and age, sweat chloride levels, and pancreatic and nutritional status. Our study demonstrates an association between interleukin-8, forced expiratory volume, and cystic fibrosis genotype. Hence, elevated interleukin-8 serum levels could serve as an indicator of an early inflammatory process and encourage the initiation of anti-inflammatory treatment.

Serum CA 19-9 levels as a diagnostic marker in cystic fibrosis patients with borderline sweat tests.

Patients with normal or borderline sweat tests present a diagnostic challenge. In spite of the availability of genetic analysis and measurement of nasal potential difference, there is still uncertainty in diagnosing cystic fibrosis in some patients. CA 19-9 is a tumor-associated antigen whose levels were previously found to be elevated in some cystic fibrosis patients. We investigated whether serum CA 19-9 levels can contribute to establishing the diagnosis of cystic fibrosis in patients with a borderline sweat test, and evaluated the influence of different clinical variables on CA 19-9 levels. Serum CA 19-9 levels were measured in 82 cystic fibrosis patients grouped according to their genotype and in 38 healthy individuals. Group A included 50 patients who carried two mutations previously found to be associated with a pathological sweat test and pancreatic insufficiency (DeltaF508, W1282X, G542X, N1303K, and S549R). Group B included 13 compound heterozygote cystic fibrosis patients who carried one mutation known to cause mild disease with a borderline or normal sweat test and pancreatic sufficiency (3849+10kb C-->T, 5T). Group C included 38 normal controls. Nineteen cystic fibrosis patients carried at least one unidentified mutation. An association between CA 19-9 levels and age, pulmonary function, pancreatic status, sweat chloride, previous pancreatitis, serum lipase, meconium ileus, distal intestinal obstruction, liver disease, and diabetes was investigated. The distribution of CA 19-9 levels was significantly different between the three groups ( p<0.01); high CA 19-9 levels were found in 60% (30/50) of group Apatients and in 46.6% (6/13) of group B patients, but in only 5.2% (2/38) of the controls. CA 19-9 levels were inversely related to forced expiratory volume in 1 s, while no association was found with the other clinical parameters examined. Our findings suggest that the serum CA 19-9 in cystic fibrosis patients originates in the respiratory system, and has a useful ancillary role, particularly when diagnostic uncertainty exists. Hence, the diagnosis of cystic fibrosis should be considered in patients with borderline sweat tests and high CA 19-9 levels, but normal levels do not exclude cystic fibrosis.

Micromethod for determination of middle ear gas composition.

This is a microchromatographic method for simultaneous determinations of O2, N2, CO2 and N2O in gas samples of 40-100 microliters. A Packard 836 U gas chromatograph with a thermal conductivity detector and helium gas as carrier was used. The combination of Porapak and 5A molecular sieve column system was found adequate and is described in detail. The fidelity of this method was proved by a high constancy of the retention time, the linearity of the response and the reproducibility of results. The present method proved to be reliable for determination of all middle ear gases in man and experimental animals during general anesthesia with N2O.

Gas scavenging during bronchoscopy under general anesthesia.

Prevention of exposure of the endoscopist to high levels of anesthetic gases during bronchoscopy was attempted experimentally in dogs by a scavenging system. Results were compared with exposure during the conventional technique of anesthetic gas administration for clinical bronchoscopy using the rigid open ventilating bronchoscope. The scavenging system consisted of a vacuum pump applied to the open ventilating rigid bronchoscope sidearm connection during intratracheal administration of nitrous oxide, , oxygen, and halothane gas mixture. Gas samples were taken from the trachea, the proximal end of the bronchoscope, and the endoscopist's breathing zone, and analyzed by gas chromatography. Findings indicate that halothane anesthesia for bronchoscopy administered by conventional techniques is a source of air pollution in the operating room and exposes the endoscopist to subanesthetic levels of halothane that may affect psychomotor functioning. The use of the gas scavenging system lowered the concentrations of halothane and nitrous oxide at the endoscopist's breathing zone to a level at which inhalation for short periods has no clinical effects, while the concentrations of the anesthetics and oxygen in the trachea were maintained at a satisfactory level.

Middle ear gas composition during nitrous oxide-oxygen ventilation.

The middle ear gas composition during 180 minutes ventilation with nitrous oxide-oxygen mixture was determined in 12 mongrel dogs. The mean relative concentration of N2O in the middle ear (ME) rose to 12,26.4 and 29.3% after 60, 120 and 180 minutes respectively. During this period, the relative concentration of N2 dropped from a mean of 83.2% in the air-ventilated dogs to 54.8%, without an essential change in the concentrations of O2 or CO2. The elimination of N2O from the ME during 30 minutes of postanesthetic ventilation with O2 was incomplete, an average of 11.4% N2O remaining in the ME. At the same time, the mean relative concentration of O2 reached 19%, higher than the O2 relative concentration normally present in the ME. The results indicate that gas diffusion may occur across the ME mucosa for N2O as well as for O2, producing selective changes in the middle ear gas composition.

The middle ear gas composition in air-ventilated dogs.

The middle ear gas composition has been examined in 5 air-ventilated dogs under sodium thiopentone anesthesia. The gas samples were obtained by transtympanic puncture and analysed by gas chromatography. The following mean +/- S.D. gas composition was obtained: N2 83.2 +/- 5.0; O2 12.1 +/- 2.2; and CO2 4.7 +/- 0.7.

[Endobronchial mass caused by tuberculosis].

A 2-year-old girl who presented with cough, had been started on prednisone and bronchodilators 10 days prior to admission because of presumed hyperactive, small airway obstruction. Fluoroscopy revealed hyperinflation of the right lung and mediastinal shift to the left on expiration. Bronchoscopy disclosed an endobronchial mass. At that time the tuberculin test was negative. Since such lesions are rare in young children, thoracotomy was performed. An enlarged mediastinal lymph node was removed and the histopathological findings were suggestive of tuberculosis. The tuberculin test 1 month following prednisone therapy was positive, suggesting that previously the skin reaction to tuberculin had been altered by the prednisone. Tuberculosis should be considered in the differential diagnosis of an endobronchial mass even in an otherwise apparently healthy child.

[Pneumothorax in cystic fibrosis: intrapleural instillation of Atabrine].

Intrapleural instillation of quinacrine HC1 (Atabrine) was used to treat spontaneous pneumothorax in 2 young men, aged 26 and 36 years, respectively, with advanced pulmonary disease due to cystic fibrosis. Pneumothorax did not recur until 1 year later in 1 case and 2 years later in the other. This mode of therapy for pneumothorax provides a valuable alternative to surgery for the patient with cystic fibrosis, severe lung disease and marginal pulmonary reserve. Quinacrine sclerosis should be considered for management of pneumothorax in cystic fibrosis because of the high rate of recurrence. However, caution should be exercised since heart-lung transplantation cannot be performed after pleural sclerosis.