[Mucoviscidosis screening with immunoreactive trypsin. Initial experiences in Austria]

Up to now, 16.338 IRT-measurements have been carried out on dried blood spot specimens; 15.505 of them were taken in the first week of life. Related to a provisionally chosen cut-off point of 750 ng/ml, 134 newborns (= 0.86%) showed an elevated IRT-value and subsequently were recalled between the fourth and sixth week of life for a second IRT-determination. Twenty-five out of 116 reinvestigated children again showed an elevated value, as based on likewise provisional, age-dependent reference values. Four of these children subsequently were identified as CF patients by sweat testing. So far, we did not encounter any false-negative IRT values. We also commenced to establish a profile of reference values for the first twelve weeks of life; as yet, there are not enough data for definitely defining these limits of normality. In conclusion, IRT-screening appears to be a reliable method for identifying CF patients in the newborn period. Our preliminary results indicate an incidence of CF of 1 to 3880 in the southeast of Austria.

Cold air challenge of airway reactivity in children: a correlation of transcutaneously measured oxygen tension and conventional lung functions

For pharmacological challenges, a correlation between the induced changes of the transcutaneously measured oxygen tension (PtcO2) and of conventional pulmonary function tests (PFTs) has been documented. We performed a 4-minute cold air challenge (CACh) in 17 children with bronchial asthma under continuous monitoring of PtcO2, and correlated observed changes with CACh-induced alterations of conventional PFTs. PtcO2 decreased significantly with CACh (from 86 +/- 10 mmHg to 66 +/- 14 mmHg, P less than 0.001), but returned to near-baseline within the next 30 minutes. PFTs changed with a similar pattern; the closest correlation was found between the CACh-induced fall of PtcO2 and Delta-FEV1 (r = 0.833, P less than 0.001). Changes of FVC, PEF, and Vmax50 correlated significantly as well. PtcO2 can complement or substitute for conventional PFTs in assessing the response to CACh in children.

Cold air challenge for measuring airway reactivity in children: lack of a late asthmatic reaction

Cold air challenge (CACh) for measuring airway reactivity uses respiratory heat or water loss as a bronchoconstrictor stimulus; this stimulus is also important for the development of exercise-induced asthma, for which late asthmatic reactions (LARs) have been described. At 1200 hr on day 1, 22 children with asthma started to record their peak expiratory flow rate (PEFR) in 3 hr intervals until 0900 hr on day 2. At 1000 hr, they underwent a standardized 4 min CACh. Children then inhaled salbutamol and continued to record PEFR until 0900 hr on day 3. As a bronchodilator effect, PEFR measurements were significantly higher 2, 5, and 8 hr after CACh, but subsequently did not differ significantly from pre-CACh values. At 5 hr after CACh, individual values ranged from 95 to 137% of the corresponding pre-CACh measurements, at 8 hr from 94 to 150%, and at 11 hr from 80 to 121%. This random sample of children with asthma demonstrated no LAR after CACh.

[Determination of theophylline serum level: comparison between a rapid test (enzyme-immuno-chromatography) and conventional fluorescence polarization immunoassay]

To evaluate the reliability and accuracy of a rapidly performed enzyme immunochromatography method for measuring the serum concentration of theophylline, we compared it with a conventional technique (fluorescence-polarisation immunoassay). We investigated 103 venous blood samples from children and adolescents with bronchial asthma, medicated with sustained-release theophylline preparations. There was a highly significant correlation of the measured values; with a few exceptions, the individual values scattered only narrowly around the regression line. Based on this close correlation, the investigated enzyme immunochromatography test can be recommended for rapid theophylline serum level determinations in clinical practice.

Airway obstruction and airway wall instability in cystic fibrosis: the isolated and combined effect of theophylline and sympathomimetics

Multiple aspects of lung function were measured in 17 cystic fibrosis (CF) patients on four occasions: without therapy (0); with oral theophylline medication (Th); after inhalation of salbutamol (beta 2); and with combined medication (Th + beta 2). In addition to routine measurements, partial and maximum expiratory flow-volume (MEFV) curves were superimposed, and the flow transient equivalent of the MEFV curve was determined. Its volume dimension (volume of airway contribution, VACMEFV) partially reflects airway distensibility. Changes in airway compressibility--the other consequence of airway wall instability--were assessed by observing changes in end-expiratory flow rate. Airway resistance, expired volumes, and early expired flow rates, as well as VACMEFV improved significantly after beta 2 medication. Mean end-expiratory flow also increased after beta 2; in two patients, however, it decreased significantly, indicating that enhanced airway compression dominated over the release of bronchospasm. The alone had only minor effects on lung function. Early expired volume and flow rates as well as VACMEFV showed no significant difference between beta 2 alone and Th + beta 2; airway resistance even decreased significantly with this drug combination. End-expiratory flow rate, however, was significantly lower after Th + beta 2 than after beta 2 alone. Although theophylline does not alter lung function in most patients with CF, sympathomimetics relieve bronchospasm in many, but they enhance airway compressibility and thereby decrease peripheral expiratory airflow in some.(ABSTRACT TRUNCATED AT 250 WORDS)