Use of airway pressure-based indices to detect high and low inspiratory effort during pressure support ventilation: a diagnostic accuracy study.

BACKGROUND: Assessment of the patient's respiratory effort is essential during assisted ventilation. We aimed to evaluate the accuracy of airway pressure (Paw)-based indices to detect potential injurious inspiratory effort during pressure support (PS) ventilation. METHODS: In this prospective diagnostic accuracy study conducted in four ICUs in two academic hospitals, 28 adult acute respiratory failure patients undergoing PS ventilation were enrolled. A downward PS titration was conducted from 20 cmH2O to 2 cmH2O at a 2 cmH2O interval. By performing an end-expiratory airway occlusion maneuver, the negative Paw generated during the first 100 ms (P0.1) and the maximal negative swing of Paw (∆Pocc) were measured. After an end-inspiratory airway occlusion, Paw reached a plateau, and the magnitude of change in plateau from peak Paw was measured as pressure muscle index (PMI). Esophageal pressure was monitored and inspiratory muscle pressure (Pmus) and Pmus-time product per minute (PTPmus/min) were used as the reference standard for the patient's effort. High and low effort was defined as Pmus > 10 and < 5 cmH2O, or PTPmus/min > 200 and < 50 cmH2O s min-1, respectively. RESULTS: A total of 246 levels of PS were tested. The low inspiratory effort was diagnosed in 145 (59.0%) and 136 (55.3%) PS levels using respective Pmus and PTPmus/min criterion. The receiver operating characteristic area of the three Paw-based indices by the respective two criteria ranged from 0.87 to 0.95, and balanced sensitivity (0.83-0.96), specificity (0.74-0.88), and positive (0.80-0.91) and negative predictive values (0.78-0.94) were obtained. The high effort was diagnosed in 34 (13.8%) and 17 (6.9%) support levels using Pmus and PTPmus/min criterion, respectively. High receiver operating characteristic areas of the three Paw-based indices by the two criteria were found (0.93-0.95). A high sensitivity (0.80-1.00) and negative predictive value (0.97-1.00) were found with a low positive predictive value (0.23-0.64). CONCLUSIONS: By performing simple airway occlusion maneuvers, the Paw-based indices could be reliably used to detect low inspiratory efforts. Non-invasive and easily accessible characteristics support their potential bedside use for avoiding over-assistance. More evaluation of their performance is required in cohorts with high effort.

Green leaf volatile (Z)-3-hexeny-1-yl acetate reduces salt stress in peanut by affecting photosynthesis and cellular redox homeostasis.

Green leaf volatiles (GLVs) are released by plants when they encounter biotic stress, but their functions in the response to abiotic stress have not been determined. We have previously shown that exogenous application of (Z)-3-hexeny-1-yl acetate (Z-3-HAC), a kind of GLV, could alleviate salt stress in peanut (Arachis hypogaea L.) seedlings; however, notably little is known concerning the transcription regulation mechanisms of Z-3-HAC. In this study, we comprehensively characterized the transcriptomes and physiological indices of peanut seedlings exposed to Z-3-HAC and/or salt stress. Analysis of transcriptome data showed that 1420 genes were upregulated in the seedlings primed with Z-3-HAC under salt stress compared with the non-primed treatment. Interestingly, these genes were significantly enriched in the photosynthetic and ascorbate metabolism-related categories, as well as several plant hormone metabolism pathways. The physiological data revealed that Z-3-HAC significantly increased the net photosynthetic rate, SPAD value, plant height and shoot biomass compared with the non-primed peanut seedlings under salt stress. A significantly higher ratio of K+ :Na+ , reduced-to-oxidized glutathione (GSH:GSSG), and ascorbate-to-dehydroascorbate (AsA:DHA) were also observed for the plants primed with Z-3-HAC compared with the salt stress control. Meanwhile, Z-3-HAC significantly increased the activity of enzymes in the AsA-GSH cycle. Taken together, these results highlight the importance of Z-3-HAC in protecting peanut seedlings against salt stress by affecting photosynthesis, cellular redox homeostasis, K+ :Na+ homeostasis, and phytohormones.

[Carbon footprint of wheat-summer direct-seeding peanut planting system in Shandong Pro-vince, China]. / 山东省小麦-夏直播花生种植体系碳足迹.

Clarifying the carbon emissions in wheat-summer direct-seeding peanut planting (W-P) system could help realize the synergistic effects of high yield and low carbon emissions. Based on whole life cycle method, we constructed a carbon footprint model to calculate the carbon emissions of W-P system. We found that the net income of W-P system was 71.2%-88.3% higher than that of wheat-maize rotation (W-M) system. The carbon emissions per unit area under W-P system was 6977.9-8018.5 kg·hm-2, being 6.2% higher than that of W-M system. The carbon emission of per net income under W-P system was 0.23-0.28 kg CO2-eq·yuan-1, which was 37.4%-44.1% lower than that of W-M system. Combining the net income and carbon emissions of per net income, W-P system could achieve synergistic effects of high yield and low carbon emissions, which would fulfill the targets of agricultural supply-side structural reform with optimizing supply, enhancing quality and efficiency, and increasing income of peasants.

Acute hemodynamic response of infused fasudil in patients with pulmonary arterial hypertension: a randomized, controlled, crossover study.

BACKGROUND: The Rho-kinase pathway has been shown to be involved in the pathogenesis of PAH. As yet, however, the acute effects of the Rho-kinase inhibitor fasudil have not been compared with established pulmonary selective vasodilators in patients with PAH. We compared the acute effects of intravenous fasudil with inhaled iloprost in patients with pulmonary arterial hypertension (PAH). METHODS: Using a crossover design, 50 patients with PAH (idiopathic PAH, PAH associated with repaired left-to-right cardiac shunts, or connective tissue disease) were randomized to iloprost inhalation (5 µg) and intravenous fasudil (30 mg over 30 min). Hemodynamic data were collected at baseline and during acute drug exposure. RESULTS: Comparable decreases were observed in mean pulmonary artery pressure (-4.6 ± 4.3 mmHg vs. -4.8 ± 4.2 mmHg) and pulmonary vascular resistance (-3.0 ± 3.0 Wood U vs. -2.2 ± 2.7 Wood U) with fasudil infusion and iloprost inhalation, respectively, during acute challenge. However, fasudil infusion resulted in a more pronounced increase in mean cardiac output and mixed venous oxygen saturation compared with iloprost inhalation (13.7 ± 17.1% vs. 6.9 ± 15.0%; p=0.044 and 4.5 ± 5.3% vs. 2.7 ± 8.2%; p=0.044, respectively). Whereas inhaled iloprost resulted in a non-significant increase in mean systemic arterial oxygen saturation (0.8 ± 3.6%), infused fasudil resulted in a non-significant reduction (-0.6 ± 1.1%). CONCLUSION: Infused fasudil improved pulmonary hemodynamics in patients with PAH without significant toxicity.

[Effects of root cutting under different seedling conditions on root system distribution and senescence character of peanut].

The effects of root cutting on root system distribution and senescence character of peanut (Arachis hypogaea) under different seedling conditions were investigated by using the box culture method. The results showed that, with three types of peanut seedlings, including overgrowing, strong and week seedlings, root cutting all first restricted and then promoted the root system growth, especially promoted the root growth to deep soil. This effect was stronger on the overgrowing and strong seedlings, while relatively weaker on the weak seedlings. After root cutting, root activity, superoxide dismutase (SOD) and peroxidase (POD) activity all reduced at first, and then increased, compared with each control. The extents of decrease in root activity, SOD and POD activity were highest in the weak seedlings, lowest in the overgrowing seedlings, and moderate in the strong seedlings. However, in the later stage after root cutting, the extents of increase in root activity, SOD and POD activity were higher in the overgrowing and strong seedlings, than in the weak seedlings. Generally, root cutting could promote the root activity of peanut and delay the senescence.

[Effects of light quality on photosynthetic pigment contents and photosynthetic characteristics of peanut seedling leaves].

This study explored the effects of different light quality on photosynthetic pigment contents and photosynthetic characteristics of peanut (Qinhua 6) seedling leaves. The results showed that, compared with natural light, blue light (445-470 nm) could significantly improve the specific leaf area (SLA), chlorophyll a/b value and carotenoid content of peanut seedlings. Meanwhile, the net photosynthetic rate, stomatal conductance, and transpiration rate were higher, the intercellular CO2 content was lower, and the photosynthetic efficiency was improved significantly under blue light. Red light (610-660 nm) could improve the chlorophyll content significantly, and reduce SLA, chlorophyll a/b value and carotenoid content, with a lower photosynthetic efficiency than natural light. Green light (515-520 nm) and yellow light (590-595 nm) were not conducive to photosynthetic pigment accumulation of leaves, and significantly inhibited leaf photosynthesis of peanut seedlings.

[Effectiveness and safety of tranexamic acid in patients receiving on-pump coronary artery bypass grafting without clopidogrel and aspirin cessation].

OBJECTIVE: To evaluate the effectiveness and safty of tranexamic acid in patients receiving on-pump coronary artery bypass grafting (CABG) without clopidogrel and aspirin cessation. METHODS: The current study is a prospective, randomized and placebo-control trial. A total of 116 patients receiving selective on-pump CABG with their last ingestion of clopidogrle and aspirin within 7 days preoperatively were recruited. Despite 6 patients withdrawal their consent, the rest 110 were randomized to receive tranexamic acid or placebo. The tranexamic acid regimen was a bolus of 10 mg/kg followed by a maintenance of 10 mg·kg(-1)·h(-1) throughout the surgery. The primary outcome was the volume of allogeneic erythrocyte transfused perioperatively. RESULTS: Baseline characteristics were comparable between the groups. In patients receiving tranexamic acid and placebo respectively, the volume of allogeneic erythrocyte transfused was 4.0 (7.5) units and 6.0(6.0) units (W = 1021, P < 0.01). In these 2 groups respectively, blood loss was 930 (750) ml and 1210 (910) ml (W = 1042, P < 0.01), the incidence of major bleeding was 50.9% and 76.4% (χ(2) = 7.70, P < 0.01), the incidence of reoperation was 0 and 9.1% (χ(2) = 5.24, P = 0.02); the volume of plasma transfused was 400 (600) ml and 600 (650) ml (W = 1072, P = 0.01), the exposure of plasma was 60.0% and 85.5% (χ(2) = 8.98, P < 0.01) and the exposure to any allogeneic blood products was 85.5% and 98.2% (χ(2) = 5.93, P = 0.01). Perioperative mortality, morbidity and the incidence of adverse events were balanced between the groups without statistical significance. CONCLUSION: Tranexamic acid reduced significantly postoperative bleeding and transfusion in patients receiving on-pump CABG without clopidogrel and aspirin cessation.

[Effects of different cultivation modes on the leaf photosynthetic characteristics and yield of summer-sowing peanut].

Taking the Arachis hypogaea cv. 'Qinghua 7' as test material, a field experiment was conducted to study the effects of different cultivation modes on the leaf photosynthetic characteristics and yield of summer-sowing peanut after wheat harvest. As compared with conventional cultivation mode, high-yield protective cultivation mode promoted the leaf growth, significantly improved the leaf area index (LAI), and maintained a longer time of high LAI and chlorophyll content. Meanwhile, the net photosynthetic rate, stomatal conductance, and transpiration rate of functional leaves under high-yield protective cultivation mode were higher while the intercellular CO2 concentration was lower, which induced the photosynthetic efficiency of functional leaves being significantly improved. Therefore, under high-yield protective cultivation mode, the yield per peanut plant was higher, the pod yield increased significantly, and the economic coefficient improved obviously. Both film mulching and straw returning could also improve the leaf photosynthesis of summer-sowing peanut, and increase the peanut yield. It was suggested that high-yield protective cultivation mode could effectively alleviate the adverse factors of summer-sowing peanut, such as the short growth period and lower productivity per plant, being a practical high-yield cultivation mode of summer-sowing peanut.

Effects of different water availability at post-anthesis stage on grain nutrition and quality in strong-gluten winter wheat.

Wheat (Triticum aestivum L.) is one of the most important agricultural crops worldwide. However, water is the most important limiting factor for wheat production. This study was initiated to test water stress environmental effects on grain quality and nutritional value of wheat by using single different water conditions at post-anthesis stage. Further analyses were conducted to examine variations in concentrations and compositions of the bioactive compounds and nutritions in strong-gluten winter wheat subjected to different levels of water deficit during grain filling. For the experiment on the response to different soil water conditions during post-anthesis stage, effects of soil water environment on protein content and composition in the grains were significant. Soil water conditions in this study greatly affected mineral contents in the grains of winter wheat, particularly with regard to the major minerals (P, K, Ca and Mg). Water deficit during grain filling can result in a decrease in lipid contents in wheat grains, which agrees well with experimental findings elsewhere. Concomitantly, a mild water deficit during grain filling would be beneficial to the grain filling and starch compositions, significantly improved bread-making quality. Therefore, it was concluded that good management of wheat field water at post-anthesis stage was helpful to improving grain quality and nutritions relevant to processing and human nutrition.

[Effects of nitrogen application rate and post-anthesis soil moisture content on the flag leaf senescence and kernel weight of wheat].

A rain-proof pool culture experiment was conducted to study the effects of nitrogen (N) application rate and post-anthesis soil moisture content on the flag leaf senescence and kernel weight of wheat. The results indicated that in all N fertilization treatments, the flag leaf SPAD value, soluble protein content, SOD and CAT activities, and photosynthetic rate decreased in the order of 60% -70% > 80%-90% >40%-50% post-anthesis soil moisture content, while the MDA content decreased in reverse order, suggesting that over high or low post-anthesis soil moisture content could cause the early senescence of flag leaves, impact grain filling, and decrease kernel weight. Under the same post-anthesis soil moisture content, the SPAD value, soluble protein content, SOD and CAT activity, and photosynthetic rate increased, while the MDA content decreased with increasing N application rate, indicating that increased N fertilization could postpone the senescence of wheat flag leaves. However, over N application was not favorable to the increase of kernel weight, especially under the condition of post-anthesis soil moisture deficiency. It was concluded that appropriate N application and post-anthesis soil moisture content control could postpone the plant senescence and increase the kernel weight of wheat.

[The effects of nitrogenous fertilizer on carbon metabolism characteristics of Glehnia littoralis].

The effects of different nitrogenous fertilizer on carbon metabolism in Glehnia littoralis were studied under the field condition. The results showed that the Sucrose Phosphat Synthase (SPS) activities and the content of soluble sugar in leaves showed the pattern of single peak curve during the growth period, and both highest level were similary appeared in the middle stage. The suitable rate of nitrogenous fertilizer can improve the SPS activities, the content of soluble sugar, the root Sucrose Synthase (SS) activities, and also kept low level of leaves soluble sugar in harvest. So it can be supply sufficient for assimilation of polysaccharide in the root as well as to increase the yield.