Effective Mechanical Insufflation-Exsufflation in a Patient With Difficulty in Sputum Discharge and Intensive Care Unit-Acquired Weakness: A Case Report.

Intensive care unit-acquired weakness (ICU-AW), a common complication in critically ill patients, may result in diaphragmatic dysfunction, which delays weaning from artificial ventilators. Here, we present the case of a patient with difficulty in sputum discharge due to ICU-AW. In the ICU, postural drainage sputum aspiration by bronchoscopy and squeezing were performed daily, but the patient's condition did not resolve. Mechanical insufflation-exsufflation (MI-E) enabled the sputum to move to the main bronchus from the peripheral bronchi, and suctioning using a bronchoscope was no longer necessary. However, the presence of sputum persisted, and MI-E was necessary after weaning, proving crucial in treating the patient with sputum discharge difficulty complicated by ICU-AW after being removed from an artificial ventilator. MI-E can be useful for patients with difficulty in sputum discharge due to ICU-AW; however, the weaning process may be prolonged in such cases.

Catalytic specificity of the Lactobacillus plantarum cystathionine γ-lyase presumed by the crystallographic analysis.

The reverse transsulfuration pathway, which is composed of cystathionine ß-synthase (CBS) and cystathionine γ-lyase (CGL), plays a role to synthesize L-cysteine using L-serine and the sulfur atom in L-methionine. A plant-derived lactic acid bacterium Lactobacillus plantarum SN35N has been previously found to harbor the gene cluster encoding the CBS- and CGL-like enzymes. In addition, it has been demonstrated that the L. plantarum CBS can synthesize cystathionine from O-acetyl-L-serine and L-homocysteine. The aim of this study is to characterize the enzymatic functions of the L. plantarum CGL. We have found that the enzyme has the high γ-lyase activity toward cystathionine to generate L-cysteine, together with the ß-lyase activity toward L-cystine to generate L-cysteine persulfide. By the crystallographic analysis of the inactive CGL K194A mutant complexed with cystathionine, we have found the residues which recognize the distal amino and carboxyl groups of cystathionine or L-cystine. The PLP-bound substrates at the active site may take either the binding pose for the γ- or ß-elimination reaction, with the former being the major reaction in the case of cystathionine.