Effectiveness of a new "focused pulse" high-frequency chest wall oscillation in patients with moderate to severe COPD

BACKGROUND

Chest physiotherapy plays a crucial role in the treatment of COPD, although the optimal techniques for airway clearance have not been definitively established. Among the different techniques, high-frequency chest wall oscillation (HFCWO) has gained attention for its potential to create a widespread lung percussion, facilitating the removal of secretions and potentially clearing the peripheral bronchial tree. This study aims to assess the effectiveness of a novel "focused pulse" HFCWO in patients with moderate to severe COPD.

METHODS

Sixty patients were randomized to three groups: a group treated with the PEP technique, a group with "focused pulse "HFCWO" and a group with pharmacological therapy alone (control group). The primary outcomes were changes in respiratory function parameters, changes in dyspnea and quality of life scores as well as daily life activity and health status assessment. The secondary outcomes were the number of exacerbations and the number of practitioner or emergency department (ED) visits after 1, 3, and 6 months.

RESULTS

Sixty patients concluded the study with 20 patients allocated to each group. The two devices improved respiratory function tests, quality of life and health scores and dyspnea compared to the control group. Maximal expiratory pressure and diffusing lung carbon oxide were significantly improved in the focused pulse HFCWO group compared to the PEP group. Only pulse-focused HFCWO showed a statistically significant lower number of exacerbations and visits to ED or practitioner compared to the control group.

CONCLUSIONS

The focused pulse HFCWO technique improves daily life activities and lung function in patients with stable COPD. The device demonstrated significantly greater effectiveness in lowering COPD exacerbations as well as visits to ED or practitioner.

Active site substitution A82W improves the regioselectivity of steroid hydroxylation by cytochrome P450 BM3 mutants as rationalized by spin relaxation nuclear magnetic resonance studies

Cytochrome P450 BM3 from Bacillus megaterium is a monooxygenase with great potential for biotechnological applications. In this paper, we present engineered drug-metabolizing P450 BM3 mutants as a novel tool for regioselective hydroxylation of steroids at position 16β. In particular, we show that by replacing alanine at position 82 with a tryptophan in P450 BM3 mutants M01 and M11, the selectivity toward 16β-hydroxylation for both testosterone and norethisterone was strongly increased. The A82W mutation led to a ≤42-fold increase in V(max) for 16β-hydroxylation of these steroids. Moreover, this mutation improves the coupling efficiency of the enzyme, which might be explained by a more efficient exclusion of water from the active site. The substrate affinity for testosterone increased at least 9-fold in M11 with tryptophan at position 82. A change in the orientation of testosterone in the M11 A82W mutant as compared to the orientation in M11 was observed by T(1) paramagnetic relaxation nuclear magnetic resonance. Testosterone is oriented in M11 with both the A- and D-ring protons closest to the heme iron. Substituting alanine at position 82 with tryptophan results in increased A-ring proton-iron distances, consistent with the relative decrease in the level of A-ring hydroxylation at position 2β.