To apply a new airway treatment to humans, preclinical studies in an appropriate animalmodel is needed. Canine, porcine and leporine tracheas have been employed as animal airwaystenosis models using various methods su...To apply a new airway treatment to humans, preclinical studies in an appropriate animalmodel is needed. Canine, porcine and leporine tracheas have been employed as animal airwaystenosis models using various methods such as chemical caustic agents, laser, and electrocautery.However, existing models take a long time to develop (3- 8 weeks) and the mechanism of stenosisis different from that in humans. The aim of the present study was to establish a new and fasttracheal stenosis model in pigs using a combination of cuff overpressure intubation (COI) andelectrocautery. Fourteen pigs were divided into three groups: tracheal cautery (TC) group (n=3),COI group (n=3), and COI-TC combination group (n=8). Cuff overpressure (200/400/500 mmHg)was applied using a 9-mm endotracheal tube. Tracheal cautery (40/60 watts) was performed usinga rigid bronchoscopic electrocoagulator. After intervention, the pigs were observed for 3 weeks andbronchoscopy was performed every 7 days. When the cross-sectional area decreased by > 50%, itwas confirmed that tracheal stenosis was established. The time for tracheal stenosis was 14 days inthe TC group and 7 days in the COI-TC combination group. In the COI group, no stenosis occurred.In the COI-TC group, electrocautery (40 watts) immediately after intubation for>1 h with a cufpressure of 200 mmHg or more resulted in suficient tracheal stenosis within 7 days. Moreover, thedegree of tracheal stenosis increased in proportion to the cuff pressure and tracheal intubation time.The combined use of cuf overpressure and electrocautery helped to establish tracheal stenosis inpigs rapidly.展开更多
Aquaporin （AQP） is a water channel protein found in various subcellular membranes of both prokaryotic and eukaryotic cells. The physiological functions of AQPs have been elucidated in many organisms. However, unders...Aquaporin （AQP） is a water channel protein found in various subcellular membranes of both prokaryotic and eukaryotic cells. The physiological functions of AQPs have been elucidated in many organisms. However, understanding their biogenesis remains elusive, particularly regarding how they assemble into tetramers. Here, we investigated the amino acid residues involved in the tetramer formation of the Arabidopsis plasma membrane AQP AtPIP2;1 using extensive amino acid substitution mutagenesis. The mutant proteins V41A/ E44A, F51A/L52A, F87A/191A, F92A/193A, V95A/Y96A, and H216A/L217A, harboring alanine substitutions in the transmembrane （TM） helices of AtPIP2;1 polymerized into multiple oligomeric complexes with a vari- able number of subunits greater than four. Moreover, these mutant proteins failed to traffic to the plasma membrane, instead of accumulating in the endoplasmic reticulum （ER）. Structure-based modeling revealed that these residues are largely involved in interactions between TM helices within monomers. These results suggest that inter-TM interactions occurring both within and between monomers play crucial roles in tetramer formation in the AtPIP2;1 complex. Moreover, the assembly of AtPIP2;1 tetramers is critical for their trafficking from the ER to the plasma membrane, as well as water permeability.展开更多
基金funded by the National Research Foundationof Korea (No. NRF-2017R1C1B5076493).
文摘To apply a new airway treatment to humans, preclinical studies in an appropriate animalmodel is needed. Canine, porcine and leporine tracheas have been employed as animal airwaystenosis models using various methods such as chemical caustic agents, laser, and electrocautery.However, existing models take a long time to develop (3- 8 weeks) and the mechanism of stenosisis different from that in humans. The aim of the present study was to establish a new and fasttracheal stenosis model in pigs using a combination of cuff overpressure intubation (COI) andelectrocautery. Fourteen pigs were divided into three groups: tracheal cautery (TC) group (n=3),COI group (n=3), and COI-TC combination group (n=8). Cuff overpressure (200/400/500 mmHg)was applied using a 9-mm endotracheal tube. Tracheal cautery (40/60 watts) was performed usinga rigid bronchoscopic electrocoagulator. After intervention, the pigs were observed for 3 weeks andbronchoscopy was performed every 7 days. When the cross-sectional area decreased by > 50%, itwas confirmed that tracheal stenosis was established. The time for tracheal stenosis was 14 days inthe TC group and 7 days in the COI-TC combination group. In the COI group, no stenosis occurred.In the COI-TC group, electrocautery (40 watts) immediately after intubation for>1 h with a cufpressure of 200 mmHg or more resulted in suficient tracheal stenosis within 7 days. Moreover, thedegree of tracheal stenosis increased in proportion to the cuff pressure and tracheal intubation time.The combined use of cuf overpressure and electrocautery helped to establish tracheal stenosis inpigs rapidly.
文摘Aquaporin （AQP） is a water channel protein found in various subcellular membranes of both prokaryotic and eukaryotic cells. The physiological functions of AQPs have been elucidated in many organisms. However, understanding their biogenesis remains elusive, particularly regarding how they assemble into tetramers. Here, we investigated the amino acid residues involved in the tetramer formation of the Arabidopsis plasma membrane AQP AtPIP2;1 using extensive amino acid substitution mutagenesis. The mutant proteins V41A/ E44A, F51A/L52A, F87A/191A, F92A/193A, V95A/Y96A, and H216A/L217A, harboring alanine substitutions in the transmembrane （TM） helices of AtPIP2;1 polymerized into multiple oligomeric complexes with a vari- able number of subunits greater than four. Moreover, these mutant proteins failed to traffic to the plasma membrane, instead of accumulating in the endoplasmic reticulum （ER）. Structure-based modeling revealed that these residues are largely involved in interactions between TM helices within monomers. These results suggest that inter-TM interactions occurring both within and between monomers play crucial roles in tetramer formation in the AtPIP2;1 complex. Moreover, the assembly of AtPIP2;1 tetramers is critical for their trafficking from the ER to the plasma membrane, as well as water permeability.
