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Aims Alpha1-antitrypsin deficiency (AATD) is a clinically under-diagnosed genetic disorder that originates from deleterious mutations in the alpha1-antitrypsin (AAT) gene, SERPINA1. Severe deficiency is associated with significant pulmonary and hepatic malfunctions. Conventional clinical diagnosis involves the evaluation of serum AAT level and detection of diseased protein isoforms. In this communication, we describe the investigations of a case of severe AATD in which the AAT levels were well below those expected from the MZ phenotype determined by isoelectric focusing for protease inhibitor type (IEF PI-typing). Methods In addition to the traditional diagnostic method that combines the assessment of serum AAT concentration and IEF PI-typing, we investigated the SERPINA1 gene of the proband and participating family members for mutations using Sanger sequencing. Results We identified a novel mutation (M409T) in the proband, initially missed by the standard diagnostic approach. The novel mutation was present in 4 out of 8 family members who participated in the study. Conclusions This report illustrates the diagnostic value of incorporating exon sequencing of the AAT gene into the algorithm for evaluating AATD, particularly when the AAT serum level is significantly lower than expected from IEF PI-typing.

Objective: To evaluate the effect of assay buffer ionic strength on assessment of the antielastase activities in bronchoalveolar lavage fluid. Method: An improved assay protocol in which elastase (in Tris-HCI buffer) is added to increasing volumes of test samples (made up to equal volume with phosphate-buffered saline) was used. Results: The percent NE activity inhibited by BALF decreased with increasing NaCl concentration of the buffer. Inhibition of pancreatic elastase (PE) was not affected. One hundred percent inhibition of NE by pure AAT and SLPI standards occurred at molar ratios of 0.91 ± 0.03 for AAT-to-NE and 0.83 ± 0.02 for SLPI-to-NE when assayed in buffer with ⩽0.15 mol NaCI/L, compared to ratios of 0.99 ± 0.02 and 1.06 ± 0.02, respectively, for assays in buffers with 0.50–1.00 mol NaCI/L (p < 0.05 for AATto-NE; p < 0.02 for SLPI-to-NE). The AAT-to-PE molar ratio at 100% inhibition of PE was not affected. Assays in buffer with ⩽0.15 mol NaCI/L indicated that 86.9 ± 4.1% of AAT and 100.9 ± 4.9% of SLPI in BALF were active against NE, while assays in buffer with 0.50–1.00 mol NaCI/L showed that 84.4 ± 3.5% of AAT and 81.6 ± 5.9% of SLPI present were active. AAT inhibited NE and PE equally only in buffer with 0.50–1.00 mol NaCI/L. Conclusions: The results of assays of BALF antielastase activities depend on the assay buffer NaCl concentration, which may account for the conflicting reports in the literature. The buffer with 0.50–1.00 mol NaCI/L appear to be optimal for valid quantitation of anti-NE activities in BALF.

We compared cardiac output determined simultaneously by two methods, the CO2 rebreathing technique and the thoracic electrical bioimpedance method (Bomed NCCOM-3 equipment). The studies were performed in duplicate in 11 healthy male subjects at rest and during three levels of steady-state exercise on a cycle ergometer at 60, 120, and 180 W. Cardiac output at 60 and 120 W was slightly lower (p less than 0.01) by the thoracic impedance method (12.2 +/- SE 2.2 and 15.7 +/- SE 3.5 L/min, respectively) than by the CO2 rebreathing method (14.0 +/- SE 2.1 and 17.9 +/- SE 3.0 L/min, respectively), suggesting a systematic bias between the two methods of measurement. However, if allowance is made for that bias, there would be acceptable agreement between the two methods at 60 and 120 W. Although the results were not significantly different between the two methods at rest and at 180 W, there was no acceptable agreement between the two methods probably because the CO2 rebreathing method at rest was more liable to show error due to the small arteriovenous CO2 difference, while the impedance method was less reliable at 180 W. Cardiac output by both methods correlated with O2 consumption, with the correlation being higher for cardiac output by the rebreathing method (r = 0.94) than for thoracic impedance (r = 0.88). The results suggest that the thoracic electrical bioimpedance method can be used for determination of cardiac output during mild or moderate levels of exercise in normal subjects.

The purpose of this study was to document the precision with which measurements can be made on a normal subject as a "biologic control" when comparisons are made both on an intralaboratory and interlaboratory basis. One individual had a total of about 300 routine pulmonary function measurements in 22 laboratories during a 13-year period. In this study, significant variation was found in interlaboratory testing, while less variation was found in intralaboratory measurements. This technique of periodic testing of normal individuals as biologic controls is useful for documenting reproducibility and precision; evaluation of accuracy will require a check of the physical calibration of the equipment. The testing (on at least a monthly basis) of a normal nonsmoking subject as a biologic control is recommended as an integral component of quality assurance in the pulmonary function laboratory.

We determined the levels of alpha 1-protease inhibitor, the plasma trypsin-inhibiting capacity (TIC), and elastase-inhibiting capacity (EIC) in 29 nonsmokers and 30 smokers, who were healthy volunteers matched for age (mean age, 39 +/- 12 years [+/- SD]). The functional activity of plasma alpha 1-protease inhibitor (in micrograms of enzyme inhibited per microgram of alpha 1-protease inhibitor) was slightly but significantly lower in smokers, compared with nonsmokers, both for TIC and EIC (smokers' TIC and EIC were 88.0 +/- 16.2 percent (+/- SD) and 90.4 +/- 17.9 percent of the respective mean values in nonsmokers; p less than 0.05). Among smokers, there was a significant negative correlation (r = -0.37; p less than 0.05) between the average number of cigarettes smoked per day and the functional activity of plasma alpha 1-protease inhibitor; the seven subjects who smoked 40 or more cigarettes per day had significantly lower EIC and TIC than the remaining smokers. In 12 smokers tested before and after a two-hour period of intense smoking of eight cigarettes, there was a statistically significant decrease (p less than 0.05) in EIC one hour after smoking to 93.9 +/- 2.5 percent (+/- SE) of the initial value prior to smoking. It is concluded that there is a slight but significant decrease in the functional activity of plasma alpha 1-protease inhibitor in smokers, both for TIC and EIC.

We studied the bronchodilator effects of inhaled fenoterol, a relatively selective beta-2 adrenergic agent, and ipratropium an anticholinergic drug, singly and in combination in 10 patients with asthma. The period of observation was 6 hr after aerosol administration. The six drug regimens used were fenoterol 100 micrograms, fenoterol 200 micrograms fenoterol 50 micrograms combined with 20 micrograms of ipratropium, fenoterol 100 micrograms combined with 40 micrograms of ipratropium, 40 micrograms of ipratropium, and placebo. Measurements consisted of spirometry with determination of forced expiratory volume in one second (FEV1), maximal expiratory flow at 50% of vital capacity (V50), specific airway conductance, lung volumes, and heart rate. Bronchodilation with regimens containing fenoterol was rapid, with 75% of the maximum response achieved by 5 min, while the peak effect of ipratropium was delayed for 1 to 2 hr. Fenoterol 100 micrograms produced approximately half the degree of improvement in FEV1 and V50 compared with 200 micrograms of fenoterol. The addition of 40 micrograms of ipratropium to 100 micrograms of fenoterol resulted in bronchodilation equivalent to 200 micrograms fenoterol and was associated with a more prolonged effect than fenoterol 100 micrograms. Tremor was observed in two-subjects inhaling fenoterol 200 micrograms but was not observed with any other regimen. It is concluded that the combination of inhaled ipratropium and fenoterol is an effective bronchodilator in asthma, achieving efficacy similar to that of fenoterol alone but with fewer side effects.