Objective To observe the effects of mechanical stretch on cytokines release from alveolar macrophages( AMs) and the expression of macrophage inflammatory protein-2( MIP-2) induced by lipopolysaccharide( LPS) . Methods AMs were divided into the following groups: ①AMs were subjected to 20% elongation by Flexercell 4000T cell stress system for 24 hours and the supernatant was collected to detect the levels of TNF-α, IL-1β, IL-2, IL-4, IL-6, IL-10, IL-12, IFN-γ, macrophage inflammatory protein-1α( MIP-1α) , MIP-2, monocyte chemoattractant protein-1( MCP-1) , granulocyte /macrophage colony stimulating factors( GM-CSF) , interferon inducible protein-10( IP-10) , regulated on activation in normal T-cell expressed and secreted( Rantes) and keratinocyte chemoattractant( KC) , by using LiquiChip system. ② AMs were subjected to 5% , 10% , 15% and 20% elongation for 24 hours and the supernatant was collected to detect the levels of MIP-2. ③AMs were subjected to 20% elongation and MIP-2 in supernatant was detected 1, 3,6, 12, and 24 hours later. ④ AMs were subjected to 20% elongation and/ or LPS at a concentration of 10 ng/mL, and MIP-2 in supernatant was detected 24 hours later. Unstretched AMs were used as control in all kind of test. Results ①The levels of IL-1β, IL-6,MIP-2, MCP-1, IFN-γand IP-10 secreted by stretched AMs were 8. 7, 4. 3, 38. 6, 4. 8, 14. 2 and 5. 0 times those of the control group( all P lt; 0. 001) . ② The levels of MIP-2 secreted by AMs subjected to 10% , 15% and 20% elongation were ( 480. 5 ±93. 1) pg /mL,( 806. 3 ±225. 9) pg/mL and ( 1335. 7 ±18. 5) pg/mL respectively, all significantly higher than those oft he control group [ ( 34. 6 ±11. 4) pg/mL, all P lt;0. 001] . ③ Three hours after the stimulation of stretch the level of MIP-2 began to increase gradually. And 6, 12, and 24 hours after the stimulation the levels of MIP-2 secreted by the AMs were ( 819. 4 ±147. 5) pg/mL, ( 1287. 6 ±380 ±3 ) pg/mL and ( 1455. 9 ±436. 7) pg/mLrespectively, all significantly higher than those of the control group[ ( 33. 4 ±10. 2) pg/mL, all P lt; 0. 001] . ④When the AMs were stimulated individually by LPS( 10 ng /mL) or mechanical stretch ( 20% ) , the levels of MIP-2 increased to ( 1026. 3 ±339. 5 ) pg/mL and ( 1335. 7 ±318. 5 ) pg/mL respectively( both P lt; 0. 001) . When the AMs were costimulated by LPS and mechanical stretch, the level of MIP-2 increased to ( 2275. 3 ±492. 1) pg/mL, implicating a synergistic effect between mechanical stretch and LPS ( F = 121. 983, P lt; 0. 001) . Conclusions Mechanical stretch activates AMs to produce multiple inflammatory cytokines and induce AMs to secret MIP-2 in a strength- and time-dependent manner.Mechanical stretch also has synergistic effect with LPS in inducing MIP-2 release, which might play an important role in the development of ventilator-induced lung injury.
ObjectiveTo observes the postoperative transformation of subjective and objective sleep quality and related influencing factors in patients with rheumatic valvular heart disease (RVHD) who were found with central sleep apnea (CSA) after cardiac valve replacement.MethodsA total of 262 patients undergoing cardiac valve replacement were screened for CSA by overnight polysomnography and 21 patients with CSA were enrolled and followed up successfully in the 3th, 6th and 12th month of postoperation from April 2010 to January 2013. The Pittsburgh Sleep Quality Index, Epworth Sleepiness, polysomnography and cardiac function were evaluated in preoperation and postoperation (in the 3th, 6th and 12th month).ResultsNew York Heart Association class ［preoperation and postoperation: (3.7±0.5), (2.3±0.6), (1.7±0.6), (1.6±0.7), F=81.124, P<0.05］ continuously decreased, left ventricular ejection fraction ［preoperation and postoperation: (58.5±6.8)%, (60.0±7.4)%, (60.9±5.6)%, (64.4±4.0)%, F=7.182, P<0.05］ steadily increased, six-minute walk distance ［preoperation and postoperation: (271.5±76.6), (422.1±71.9), (445.1±56.2), (454.5± 63.5) m, F=67.134, P<0.05］ constantly increased. During postoperative follow-up, sleep apnea-hypopnea index ［preoperation and postoperation: (26.2±13.4), (12.0±11.5), (8.6±7.5), (7.4±5.5)/h, F=20.548, P<0.05, central sleep apnea index ［preoperation and postoperation: (19.6±10.3), (0.5±1.5), (0.3±1.3), (0.2±0.7)/h, F=72.926, P<0.05］ and oxygen desaturation index ［preoperation and postoperation: (20.1±16.6), (10.8±9.5), (8.5±7.2), (6.1±5.1)/h, F=9.646, P<0.05］ sustained improved. Aroual index ［preoperation and postoperation: (23.1±12.1), (2.7±3.8), (3.5±4.8), (2.2±2.1)/h, F=58.370, P<0.05］ presented overall downward trend. Pittsburgh Sleep Quality Index scale ［preoperation and postoperation: (11.1±3.2), (8.2±3.3), (6.0±3.8), (4.4±2.5), F=27.670, P<0.05］ were constantly improved. Epworth Sleepiness scale ［preoperation and postoperation: (13.3±5.7), (6.9±4.5), (8.2±4.8), (6.1±3.7), F=15.994, P<0.05］ showed overall reduction.ConclusionThe sleep quality of patients with RVHD and CSA is improved after cardiac valve replacement, of which the trend is in keep with postoperative recovery of cardiac function.
ObjectiveTo investigate the biomechanical influence of the oblique locking plate on the fixation of femoral shaft fracture. MethodsForty imitation artificial femur model with mechanical properties similar to human femur were selected and randomly divided into groups A, B, C, and D, 10 in each group; the femur fracture model was made by transverse osteotomy at 15 cm and 17 cm below the lesser trochanter of the femur and fixed with locking plate with 12 holes and cortical bone screws. The plate was placed in the middle of the longitudinal axis of the femur in group A, and was placed at 5, 10, and 15° angle axis in groups B, C, and D respectively. The axial compression, three-point bending, torsion tests were carried out to measure the strain. ResultsWith the compressive load and bending load increasing, the medial and lateral strains were significantly increased in each group (P<0.05); but no significant difference was found in strains under compressive load and bending load among 4 groups (P>0.05). With increasing torque, the strain was significantly increased in each group (P<0.05). At 10 N·m torque, there was no significant difference in the strain values among 4 groups (P>0.05); the strain value was significantly higher in groups C and D than groups A and B (P<0.05) and in group D than group C (P<0.05) at torque of 20 and 50 N·m, but no significant difference was found between groups A and B (P>0.05). ConclusionUnder different stress, the strain will be significantly increased when the plate is placed at >10° angle axis.
Objectives To explore the efficacy of humidified and heated high flow oxygen therapy for the critically ill patients in intensive care unit (ICU) after extubation. Methods From January 2014 to December 2016, 487 patients were enrolled. Patients were allocated to two treatment groups randomly, which were humidified and heated high flow oxygen therapy group (236 patients, HFM group, aged 55.3±21.1 years old) and routine oxygen therapy group (251 patients, TO group, aged 58.4±19.3 years old). Blood oxygen saturation, arterial partial pressure of oxygen (PaO2), arterial partial pressure of carbon dioxide (PaCO2), fraction of inspired oxygen (FiO2), respiratory frequency, incidence rate of reintubation, ventilator-free days, ICU length of stay, and hospital stay were assessed and compared between the HFM group and the TO group. Results The hospital stay was similar in two groups. There were more ventilator-free days in the HFM group (P<0.05), fewer patients required reintubation (4.2%vs. 10.4%, P<0.05) and less ICU length of stay [(10.5±6.1) dvs. (14.3±8.5) d, P<0.05]. PaO2/FiO2 of the HFM group were better than the TO group after extubation at 2 h, 4 h, 8 h, 24 h, and 48 h (P<0.05). There were no statistically significant differences in respiratory frequency and PaCO2. Conclusions Humidified and heated high flow oxygen therapy can supply a better oxygenation for patients after extubation in ICU. It could be a common therapy in ICU for the critically patients after extubation.