有创-无创序贯机械通气对急性心源性肺水肿患者低氧血症和血流动力学的影响

目的:探讨有创-无创序贯机械通气对急性心源性肺水肿患者低氧血症及血流动力学的影响。方法:按照随机数字表法将2013年3月至2015年3月我院收治的49例急性心源性肺水肿患者分为两组,对照组行常规抗心衰治疗联合有创机械通气,观察组接受对照组治疗方案后,再给予无创鼻面罩双水平气道正压通气。比较两组患者治疗前后的动脉血气分析指标及血流动力学指标,以及有创机械通气时间、机械通气总时间、呼吸机相关肺炎(VAP)发生率、再发心衰率及死亡例数。结果:两组患者治疗过程中未出现死亡病例,治疗后,两组患者动脉血气分析指标、血流动力学指标较治疗前不同程度的改善,差异有统计学意义(P0.05),两组患者治疗后的动脉血气分析指标、血流动力学指标比较,差异无统计学意义(P0.05)。观察组患者有创通气时间、通气总时间少于对照组,VAP发生率低于对照组,差异有统计学意义(P0.05),两组患者再发心衰率差异无统计学意义(P0.05)。结论:有创-无创序贯机械通气能有效改善急性心源性肺水肿患者的低氧血症和血流动力学指标,安全有效,作为抢救急性心源性肺水肿的措施具有重要临床价值。     

Association of IL-8-251A/T polymorphism with incidence of Acute Respiratory Distress Syndrome (ARDS) and IL-8 synthesis after multiple trauma

INTRODUCTION: Interleukin-8 (IL-8) is regarded as one of the most important mediators in the pathogenesis of Adult Respiratory Distress Syndrome (ARDS). However, knowledge regarding the influence of genetic variations within the IL-8 gene either on the development of ARDS or on IL-8 production in the traumatic setting is sparse. PATIENTS AND METHODS: In this prospective cohort study, patients were included if the following criteria were fulfilled: Injury Severity Score (ISS) >16, age 18-60 years and a survival >48 h after injury. Systemic IL-8 concentrations and the polymorphisms (IL-8-251A/T) were determined. Patients were separated according to the development of ARDS (group +ARDS vs. group -ARDS) and the genotypes of the IL-8-251A/T polymorphism (genotypes A/A, A/T and T/T). RESULTS: Group +ARDS demonstrated significantly higher IL-8 plasma concentrations from day 3 until the end of the observation period compared to group -ARDS. In addition, duration of mechanical ventilation and length of stay in the ICU were significantly longer in this group. Furthermore, a significant association between the IL-8-251A allele and IL-8 production (day 4-8) was observed. Genotype A/A showed a significantly longer duration of mechanical ventilation compared to genotype T/T. A trend towards an association between the IL-8-251A allele and an increased incidence of posttraumatic ARDS was observed (p=0.08). CONCLUSION: This data reaffirms a central role of IL-8 in the pathogenesis of ARDS. Furthermore, it points towards a genetic predisposition for posttraumatic IL-8 synthesis which might also be associated with the development of posttraumatic ARDS.     

麻醉大鼠左心室插管新方法

目的：探索在0．014’’经皮冠状动脉（PTCA）指引导丝引导下行大鼠左心室插管的方法。方法：30只Wistar大鼠,先后在PTCA导丝引导经右侧颈外动脉,左侧颈外动脉插管至左心室并行血流动力学测定：结果：30只大鼠成功完成一次左心室重复插管,27只大鼠完成重复插管：结论：PTCA指引导丝引导下左心室插管安全并可重复操作。     

吸入不同浓度 CO_2对肺通气功能影响的实验观察

本实验在10名健康男性青年中观察了吸入0.5—7%CO_2对肺通气功能的影响。实验结果表明,呼吸频率、潮气量、肺通气量、肺泡 CO_2分压以及肺通气对 CO_2的反应性均与吸入气CO_2浓度成线性关系。被试者吸入 CO_2后,CO_2排出量减少;但浓度不超过5%时,3—5min 内CO_2排出量即可基本恢复到正常水平。本文根据人体 CO_2反应的这些特点提出了三个代偿区的意见。     

Neurophysiological analysis of locust behaviour during ecdysis: The slow rhythm underlying expansion

The behaviour of Schistocerca during the expansional stage of the imaginal ecdysis was analysed using electromyograms. The behaviour of the abdomen consisted of a slow rhythm in which tonic compressions and rapid ventilation alternated. The same abdominal motor neurones were excited in the tonic compression and rapid expiratory strokes. The results suggest that different interneurones excited the motor neurones in these two phases. The excitation of muscles in the head and thorax was also correlated with the abdominal rhythm.     

Endothelin- and Sarafotoxin-Induced Phosphoinositide Hydrolysis in Cultured Canine Tracheal Smooth Muscle Cells

Abstract: The endothelins (ETs) and sarafotoxin are two structurally related classes of potently contractile peptides. To understand the mechanism of action of ETs, we have examined the effect of ETs and sarafotoxin on phosphoinositide (PI) hydrolysis in cultured canine tracheal smooth muscle cells (TSMCs). ET-1, ET-2, ET-3, and sarafotoxin caused dose-dependent accumulation of inositol phosphates (IPs) and tracheal smooth muscle contraction. BQ-123, an ET_A receptor antagonist, had a high affinity to block the ET-1-induced IP accumulation and tracheal smooth muscle contraction with pK_B values of 7.3 and 7.4, respectively. Pretreatment of TSMCs with cholera toxin impaired the ability of ET-1 and ET-2 to stimulate IP formation, whereas there was no effect by treatment with pertussis toxin. Stimulation of PI turnover by these peptides required the presence of extracellular Ca²⁺ and was blocked by treatment with EGTA. The addition of Ca²⁺(3–620 nM) to digitonin-permeabilized TSMCs directly stimulated IP accumulation. A further Ca²⁺-dependent increase in IP formation was obtained by inclusion of either GTPrS or ET-1. The combined presence of GTPrS and ET-1 elicited an additive effect on IP formation. Short-term exposure to phorbol 12-myristate 13-acetate (PMA, 1 μM) abolished the stimulation of PI hydrolysis induced by these peptides. The inhibitory effect of PMA on ET-induced response was reversed by staurosporine, a protein kinase C (PKC) inhibitor, suggesting that the inhibitory effect of PMA is mediated through the activation of PKC. Prolonged incubation of TSMCs with PMA resulted in a recovery of receptor responsiveness that may be due to down regulation of PKC. Inactive phorbol ester, 4α-phorbol 12, 13-didecanoate at 1 μM, did not inhibit this response. The site of this response was further investigated by examining the effect of PMA on AIF₄^?-induced IP accumulation in canine TSMCs. AIF₄^?-induced IP accumulation was inhibited by PMA treatment, suggesting that G protein(s) can be directly activated by AIF₄^?, which was uncoupled to phospholipase C by PMA treatment. These data conclude that ET-stimulated PI hydrolysis and tracheal smooth muscle contraction are mediated by the activation of ET_Areceptors coupling to a G protein and dependent on the external Ca²⁺. The transduction mechanism of ETs is sensitive to feedback regulation by PKC.     

Respiratory responses to hypoxia in relation to mode of life of two erythrinid species (Hoplias malabaricus and Hoplias lacerdae)

Predominantly, Hoplias malabaricus inhabits stagnant O₂ poor environments, whereas Hoplias lacerdae occurs in well-aerated streams. The present study evaluates the influence of mode of life on O₂ uptake and gill ventilation in equally-sized (300 g) specimens of this genus at 25° C. Comparing the species, H. lacerdae was characterized by the highest O₂ uptake and gill ventilation combined with a relatively higher cost of breathing and a lower O₂ extraction. Both species substantially increased ventilation in response to hypoxia with the difference that H. malabaricus exclusively augmented tidal volume, whereas H. lacerdae also increased breathing frequency.     

Stomatal and cuticular traits on carnation tissue culture under different ventilation conditions

Establishment of microplants is related to the moisture vapourtransmission of the culture vessel lid. In this respect, stomatal andcuticular physiology were characterized in detached leaves from Dianthuscaryophyllus grown in the glasshouse or in vitro at different rates ofventilation. In vitro plants grown in non-ventilated culture vessels hadless waxes and therefore higher RWL compared to in vitro plants grown at Vr0.86 changes.h^–1. The improvement of stomatal function inleaves obtained in ventilated vessels can be due to a performance of ionicrelations between guard and subsidiary cells, mainly by an increasingK⁺ concentration in the guard cells as ventilation decreases.Moreover, data showthat there is an increase in free ABA in the leavesfromventilated culture vessels to compensate for the conjugated ABA lostduring desiccation. If the proliferation stage proceeds in ventilatedculture vessels, the physiological characteristics of the plants producedare better than those obtained in non-ventilated culture vessels, confirmedby higher survival after soil transplantion.     

Identification of Bordetella pertussis virulence-associated outer membrane proteins

Bordetella pertussis virulence-associated 30-, 32-, 90- and 95-kDa outer membrane proteins were purified and their N-terminal amino acid sequences were determined. The 30- and 32-kDa outer membrane proteins showed identity to the C-terminal region of the precursors of the serum resistance protein (BrkA) and the tracheal colonization factor, respectively. We confirmed the cleavage site of these precursors after N731 for BrkA and after N393 for tracheal colonization factor. Associated with the 32-kDa outer membrane protein, we found a new group of 36-kDa virulence-associated peptides. The 95-kDa outer membrane protein showed identity to Vag8. The 90-kDa outer membrane protein did not show homology with the described proteins. We report the N-termini sequence of Vir-90, a novel potential virulence factor.     

EGF signalling regulates cell invagination as well as cell migration during formation of tracheal system in Drosophila

 The Drosophila tracheal system is a network of epithelial tubes that arises from the tracheal placodes, lateral clusters of ectodermal cells in ten embryonic segments. The cells of each cluster invaginate and subsequent formation of the tracheal tree occurs by cell migration and fusion of tracheal branches, without cell division. The combined action of the Decapentaplegic (Dpp), Epidermal growth factor (EGF) and breathless/branchless pathways are thought to be responsible for the pattern of tracheal branches. We ask how these transduction pathways regulate cell migration and we analyse the consequences on cell behaviour of the Dpp and EGF pathways. We find that rhomboid (rho) mutant embryos display defects not only in tracheal cell migration but also in tracheal cell invagination unveiling a new role for EGF signalling in the formation of the tracheal system. These results indicate that the transduction pathways that control tracheal cell migration are active in different steps of tracheal formation, beginning at invagination. We discuss how the consecutive steps of tracheal morphogenesis might affect the final branching pattern. Received: 9 October 1998 / Accepted: 5 November 1998