Trajectories of functional exercise capacity in patients undergoing pulmonary rehabilitation.

Background: Pulmonary rehabilitation (PR) is now considered fundamental when managing patients with chronic respiratory disease. The individual variation in functional exercise capacity (FEC) response to PR within the cohort is unknown. The purpose of this study was to identify FEC patterns in response to PR in patients with chronic respiratory disease using the trajectory modeling method. Methods: The data of 67 patients with the chronic respiratory disease were retrospectively reviewed and analyzed in this study. All patients received once-weekly supervised training for 8 weeks. Six-minute walk distance (6MWD) was used to measure FEC. Muscle strength and 6MWD were assessed at baseline, Week 4, Week 8 and monthly for two months after PR completion. Group-based trajectory modeling (GBTM) was used to identify patterns in 6MWD in response to PR. The generalized estimating equation method was then used to detect the differences within and between the trajectories of identified groups across time. Results: Patients were grouped into low- (n=13), moderate- (n=34) and high- (n=20) FEC group based on GBTM analysis. All groups demonstrated significant improvements in 6MWD and leg muscle strength after 8-week PR. Compared to the high-FEC group, a greater proportion of the patients in the low-FEC group required oxygen supplementation during training and had worse baseline leg muscle strength. Conclusions: Patients showed distinct patterns of 6MWD changes in response to 8-week PR. Distinct characteristics for the low-FEC group included poor lower extremity strength and a greater proportion of required oxygen use at home and during training.

Stereoselective synthesis of (R)-phenylephrine using recombinant Escherichia coli cells expressing a novel short-chain dehydrogenase/reductase gene from Serratia marcescens BCRC 10948.

(R)-Phenylephrine [(R)-PE] is an α1-adrenergic receptor agonist and is widely used as a nasal decongestant to treat the common cold without the side effects of other ephedrine adrenergic drugs. We identified a short-chain dehydrogenase/reductase (SM_SDR) from Serratia marcescens BCRC 10948 that was able to convert 1-(3-hydroxyphenyl)-2-(methylamino) ethanone (HPMAE) into (R)-PE. The SM_SDR used NADPH and NADH as cofactors with specific activities of 17.35±0.71 and 5.57±0.07mU/mg protein, respectively, at 30°C and pH 7.0, thereby indicating that this enzyme could be categorized as an NADPH-preferring short-chain dehydrogenase/reductase. Escherichia coli strain BL21 (DE3) expressing SM_SDR could convert HPMAE into (R)-PE with more than 99% enantiomeric excess. The productivity and conversion yield were 0.57mmolPE/lh and 51.06%, respectively, using 10mM HPMAE. Fructose was the most effective carbon source for the conversion of HPMAE to (R)-PE.

Purification and characterization of a novel extracellular tripeptidyl peptidase from Rhizopus oligosporus.

A novel extracellular tripeptidyl peptidase (TPP) was homogenously purified from the culture supernatant of Rhizopus oligosporus by sequential fast protein liquid chromatography. The purified enzyme was a 136.5 kDa dimer composed of identical subunits. The effects of inhibitors and metal ions indicated that TPP is a metallo- and serine protease. TPP was activated by divalent cations, such as Co(2+) and Mn(2+), and completely inhibited by Cu(2+). Enzyme activity was optimal at pH 7.0 and 45 °C with a specific activity of 281.9 units/mg for the substrate Ala-Ala-Phe-pNA. The purified enzyme catalyzed cleavage of various synthetic tripeptides but not when proline occupied the P1 position. Purified TPP cleaved the pentapeptide Ala-Ala-Phe-Tyr-Tyr and tripeptide Ala-Ala-Phe, confirming the TPP activity of the enzyme.