PNS exerted a protective effect against MV-induced diaphragm dysfunction by counteracting altered expression of IGF-1 and ubiquitin ligase in the diaphragm.
The tensile behaviour of solution annealed type 304L, solution annealed type 304, and solution annealed and sensitised type 304 stainless steels was investigated in hydrogen and helium under a pressure of 1 . 1 MPa over the temperature range 300 ± 80 K at strain rates ranging from 4 . 2610 25 to 4 . 2610 22 s 21 . For 304L steel, hydrogen environment embrittlement (HEE) increased with decreasing strain rate. For 304L and 304 steels, HEE increased with decreasing temperature, reached a maximum, and then decreased with further decrease in temperature: the decrease was particularly rapid near the minimum temperature for HEE. Sensitisation enhanced the HEE of 304 steel. Above the maximum HEE temperature, the HEE behaviour was similar to the hydrogen embrittlement behaviour of materials in previous studies, but near the minimum temperature for HEE it was different. Three types of hydrogen induced brittle fracture were observed as a result of HEE: transgranular fracture along strain induced martensite laths and twin boundary fracture on the fracture surfaces of solution annealed 304L and 304 steels, and grain boundary fracture on the sensitised 304 steel. It was found that from room temperature to the maximum HEE temperature, the HEE of the materials depended on the transformation of strain induced martensite and below the maximum HEE temperature it depended on the diffusion of hydrogen.MST/4709
Sepsis can often induce diaphragm dysfunction, which is associated with localized elaboration of cytokines within the diaphragm. The administration of cisatracurium has been shown to decrease the inflammatory response and to facilitate mechanical ventilation. In this study, we explored whether cisatracurium could attenuate sepsis-induced diaphragm dysfunction in rats. Animals were divided into three groups: (1) the control group: rats underwent a sham surgical procedure with cecal exposure, but the cecum was neither ligated nor punctured; (2) the CLP group: rats underwent cecal ligation and puncture (CLP) and received a continuous infusion of NaCl 0.9 %; and (3) the Cis + CLP group: rats underwent CLP and received a continuous infusion of cisatracurium. After the surgical procedure, all animals underwent controlled mechanical ventilation for 18 h. Plasma concentrations of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and high-mobility group box 1 (HMGB1) were measured using an enzyme-linked immunosorbent assay. Upon completion of the experimental protocol, diaphragm contractility and HMGB1 protein expression were analyzed. Impaired diaphragm contractile function, including both force-related properties and force-frequency responses, was pronounced after CLP in comparison with that observed in the control rats. Furthermore, CLP elevated serum levels of IL-6, TNF-α, and HMGB1, and induced HMGB1 protein expression in the diaphragm. In contrast, cisatracurium counteracted the sepsis-induced inflammation reaction in the diaphragm and serum and maintained diaphragm function. These data suggest that early infusion of cisatracurium attenuates sepsis-induced diaphragm dysfunction; this may be attributable to its anti-inflammatory action.
Aim: To investigate the changing resistance to nondepolarizing muscle relaxants (NDMRs) during the first month after denervation. Methods: The denervated and innervated skeletal muscle cells were examined on days 1, 4, 7, 14, 21, and 28 after denervation. Individual denervated and innervated cells were prepared from the flexor digitorum brevis of the surgically denervated and contralateral hind feet, respectively. Nicotinic acetylcholine receptors (nAChRs) in the cells were activated with 30 µmol/L acetylcholine, either alone or in combination with various concentrations of vecuronium. Currents were recorded using a whole-cell patch-clamp technique. Results: The concentrations of vecuronium resulting in half-maximal inhibitory responses (IC 50 ) increased 1.2-(P>0.05), 1.7-, 3.7-, 2.5-, 1.9-, and 1.8-fold (P<0.05) at Days 1, 4, 7, 14, 21, and 28 after denervation, respectively, compared to the innervated control. Resistance to vecuronium appeared at Day 4, peaked at Day 7, and declined at Day 14 after denervation. Nevertheless, IC 50 values at Day 28 remained significantly higher than those for the innervated control, suggesting that the resistance to vecuronium had not disappeared at Day 28. Conclusion: The NDMR doses required to achieve satisfactory clinical effects differ at different times after muscle denervation.
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