Epidural administration of large dose of opioid µ receptor agonist may impair cardiac functions and myocardial viability via desensitizing transient receptor potential vanilloid 1.

The incidence of postoperative myocardial injury remains high as the underlying pathogenesis is still unknown. The dorsal root ganglion (DRG) neurons express transient receptor potential vanilloid 1 (TRPV1) and its downstream effector, calcitonin gene-related peptide (CGRP) participating in transmitting pain signals and cardiac protection. Opioids remain a mainstay therapeutic option for moderate-to-severe pain relief clinically, as a critical component of multimodal postoperative analgesia via intravenous and epidural delivery. Evidence indicates the interaction of opioids and TRPV1 activities in DRG neurons. Here, we verify the potential impairment of myocardial viability by epidural usage of opioids in postoperative analgesia. We found that large dose of epidural morphine (50 µg) significantly worsened the cardiac performance (+dP/dtmax reduction by 11% and -dP/dtmax elevation by 24%, all P < 0.001), the myocardial infarct size (morphine vs Control, 0.54 ± 0.09 IS/AAR vs. 0.23 ± 0.06 IS/AAR, P < 0.001) and reduced CGRP in the myocardium (morphine vs. Control, 9.34 ± 2.24 pg/mg vs. 21.23 ± 4.32 pg/mg, P < 0.001), while induced definite suppression of nociception in the postoperative animals. It was demonstrated that activation of µ-opioid receptor (µ-OPR) induced desensitization of TRPV1 by attenuating phosphorylation of the channel in the dorsal root ganglion neurons, via inhibiting the accumulation of cAMP. CGRP may attenuated the buildup of ROS and the reduction of mitochondrial membrane potential in cardiomyocytes induced by hypoxia/reoxygenation. The findings of this study indicate that epidurally giving large dose of µ-OPR agonist may aggravate myocardial injury by inhibiting the activity of TRPV1/CGRP pathway.

Identifying interactions of linked irrigated lake-groundwater system by combining hydrodynamic and hydrochemical method.

During the irrigation period, the interactions between the linked lake-groundwater systems are complicated and change. This is because natural and human activities are happening at the same time, which makes it harder to identify the interactions. This study uses data on water level, hydrochemistry, and hydrogen-oxygen stable isotopes to analyze the hydrodynamics, electrical conductivity (EC), isotopic characteristics, and spatial distribution of lake water and groundwater to reveal lake-groundwater interactions. The results indicate that the hydrochemical type of Chagan Lake and groundwater is dominated by the HCO3-Na type. The key hydrochemical indicator EC obtained by principal component analysis (PCA) can be used to reveal the lake-groundwater interaction, and the interaction should be identified by location according to the significant correlation between hierarchical clustering results and regional distribution. The lake body's geographic coefficient of variation for EC and δ18O is small, and irrigation return flow is one factor in the region's surface water's significant spatial variation for EC and δ18O. The three study methods indicate that the groundwater supplies the lake in the vicinity of the Huoling River-Hongzi Pool, while in other sections, the lake water leaks and replenishes the groundwater, exhibiting geographic inconsistency. The isotope method was employed as a support tool to determine that groundwater might recharge the lake at Xinmiao Pool. According to the calculations of the Mix SIAR model, the groundwater recharge contribution rate in the Xinmiao Pool section is approximately 51%, while in the remaining sections, the contribution rate of lake water to groundwater ranges from approximately 25% to 52%. Therefore, the identification of the interaction is crucial for the linked irrigated lake-groundwater system where water sources are scarce and threatened by agricultural pollution.

A modeling approach to the efficient evaluation and analysis of water quality risks in cold zone lakes: a case study of Chagan Lake in Northeast China.

Due to the influence of complex regional climate, water quality perturbation factors of lakes in cold regions are complicated, and the uncertainty of each factor needs further study. This study coupled two algorithms (clustering and EM) to establish a water quality uncertainty model of Chagan Lake, a typical cold region lake in China. A BN model containing nine influencing factors (including water temperature (WT), total phosphorus (TP), total nitrogen (TN), etc.) was established and optimized, and sensitivity analysis was also performed. The results indicate that the water quality status of the lake is class III and 27.47% risk of exceeding the standard. The water quality of the lake is more susceptible to disturbance during the freezing period (WT < 1 °C). TP is the most sensitive factor for water quality disturbance in the lake followed by chemical oxygen demand (COD), TN, and fluoride (F). Parameter control result displays, and the multifactor synergistic control scheme could reduce the water quality risk of the lake by 36.47%. This study demonstrates that our proposed method can be used to predict both sudden water quality events and the overall trend of water quality fluctuation, which is important for rapid water quality evaluation and management decisions.

Effect of different position on inferior vena cava dimensions and its influence on hemodynamics during cesarean section under combined spinal-epidural anesthesia: A randomized controlled trial.

OBJECTIVE: The purpose of our study was to investigate the effect of the 15° left operating table tilt on the inferior vena cava (IVC) and the hemodynamics of full-term pregnant women, and to evaluate the efficacy of inferior vena cava collapse index (IVCCI) in predicting hypotension. METHODS: All parturients planning to perform cesarean section (CS) were randomly divided into supine group and 15° group. Their parameters of IVC were measured by ultrasound and then calculated the IVCCI. Systolic blood pressure (SBP), mean arterial pressure (MAP), and heart rate (HR) in two positions were recorded from baseline to fetal delivery. RESULTS: The IVCCI in the 15° group was significantly lower when compared with that in the supine group (20.40 [18.84-21.60] vs. 21.82 [20.16-22.79] %, p = 0.012). The incidence of hypotension was observed statistically lower in the 15° group than the supine group (27.5% vs. 50%, p = 0.039). Best cut-off value was 21.69% and area under the receiver operating characteristic (ROC) curve of IVCCI in supine position to predict hypotension was 0.93. Best cut-off value was 21.78% and area under the ROC curve of IVCCI in supine position to predict hypotension was 0.80. CONCLUSIONS: The 15° left operating table tilt can relieve the extent of compression of IVC and reduce the incidence of hypotension. IVCCI can predict the occurrence of hypotension.

iTRAQ Proteomic Analysis of Wheat (Triticum aestivum L.) Genotypes Differing in Waterlogging Tolerance.

Transient and chronic waterlogging constrains crop production in many regions of the world. Here, we invoke a novel iTRAQ-based proteomic strategy to elicit protein synthesis and regulation responses to waterlogging in tolerant (XM 55) and sensitive genotypes (YM 158). Of the 7,710 proteins identified, 16 were distinct between the two genotypes under waterlogging, partially defining a proteomic basis for waterlogging tolerance (and sensitivity). We found that 11 proteins were up-regulated and 5 proteins were down-regulated; the former included an Fe-S cluster assembly factor, heat shock cognate 70, GTP-binding protein SAR1A-like and CBS domain-containing protein. Down-regulated proteins contained photosystem II reaction center protein H, carotenoid 9, 10 (9', 10')-cleavage dioxygenase-like, psbP-like protein 1 and mitochondrial ATPase inhibitor. We showed that nine proteins responded to waterlogging with non-cultivar specificity: these included 3-isopropylmalate dehydratase large subunit, solanesyl-diphosphate synthase 2, DEAD-box ATP-dependent RNA helicase 3, and 3 predicted or uncharacterized proteins. Sixteen of the 28 selected proteins showed consistent expression patterns between mRNA and protein levels. We conclude that waterlogging stress may redirect protein synthesis, reduce chlorophyll synthesis and enzyme abundance involved in photorespiration, thus influencing synthesis of other metabolic enzymes. Collectively, these factors accelerate the accumulation of harmful metabolites in leaves in waterlogging-susceptible genotypes. The differentially expressed proteins enumerated here could be used as biological markers for enhancing waterlogging tolerance as part of future crop breeding programs.

Thermal safety margins of plant leaves across biomes under a heatwave.

Climate change has great impacts on forest ecosystems, especially with the increasing frequency of heatwaves. Thermal safety margin (TSM) calculated by the difference between body temperature and thermotolerance threshold is useful to predict thermal safety of organisms. It has been widely used for animals, whereas has rarely been reported for plants. Besides, most of the previous studies used only thermotolerance to estimate thermal safety or used thermotolerance and air temperature (Ta) to calculate TSM. However, leaf temperature (Tl) is the real "body" temperature of plant leaves. Tl decoupling from Ta might induce large error in TSM. Here, we investigated TSM of photosystem II (thermotolerance of PSII - the maximum Tl) of dominant canopy plants in four forests from tropical to temperate biomes during a heatwave, and compared the TSMs calculated by Tl (TSM.Tl) and Ta (TSM.Ta) respectively. Also, thermal related leaf traits were investigated. The results showed that both TSM. Tl and TSM.Ta decreased from the cool forests to the hot forests. TSM.Tl was highly correlated with the maximum leaf temperature (Tlmax), while had an opposite trend with thermotolerance across biomes. Thus, Tlmax instead of thermotolerance can be used to evaluate TSM. The maximum Ta (Tamax), Tlmax and leaf traits explained 68% of the variance of thermotolerance in a random forest model, where Tamax and Tlmax explained 62%. TSM.Ta could not distinguish thermal safety differences between co-occurring species. The overestimation of TSM by TSM.Ta increased from the tropical to the temperate forest, and increased with Tl within biome. Therefore, it is not recommended to use TSM.Ta in cold forests. The present study enriches the dataset of photosynthetic TSMs across biomes, proposes using Tlmax to estimate TSMs of leaves, and highlights the risk of hot dry forest during heatwaves.

Perceptions of orthodontists, laypersons, and patients regarding buccal corridors and facial types.

INTRODUCTION: The space on each side of the mouth, between the commissure of the mouth and the buccal surface of the last visible tooth, is called the buccal corridor. The size of the buccal corridor can affect perceptions of facial esthetics. We analyzed the perceptions of orthodontists, laypersons, and orthodontic patients regarding the size of buccal corridors in people with brachyfacial, mesofacial, and dolichofacial types. METHODS: Photographs of 1 male and 1 female model were modified digitally into brachyfacial, mesofacial, and dolichofacial types. Each facial type was further modified to create 5 sizes of buccal corridors. Orthodontists, adult orthodontic patients, and laypersons were invited to rate the photographs. RESULTS: Orthodontists rated lower than the other groups of raters when they evaluated the female model with the buccal corridors of 20% (P <0.05). Laypersons could not distinguish the changes of the buccal corridors when evaluating the male model with brachyfacial and mesofacial (P >0.05). Orthodontic patients rated significantly higher than the orthodontists and the laypersons when evaluating the dolichofacial type of both models (P <0.05). CONCLUSIONS: Orthodontists are more sensitive to the buccal corridors than are orthodontic patients and laypersons. It is only necessary to consider eliminating the patient's buccal corridors when the buccal corridor area ratio is over 15%.

Identification of Young's modulus and equivalent spring constraint boundary conditions of the soft tissue with locally observed displacements for endoscopic liver surgery.

In endoscopic surgery, the surgical navigation system needs to calculate the deformation of soft tissue by biomechanical model which requires elastic properties and boundary conditions. However, patient-specific elastic parameters and boundary conditions of soft tissue are hard to measure accurately from the preoperative images, especially the boundary conditions will change during the operation due to the ligament cutting. In addition, simple boundary conditions such as fixed constraints and free-force constraints are not physically adequate to simulate the elastic effect of ligaments attached to the liver. In this paper, we present a novel method to identify the Young's modulus and equivalent spring constraint boundary conditions of a locally observed soft tissue. Based on the spring constraint boundary condition, a two-step inverse algorithm is developed based on the finite element method (FEM) with integration of energy regularized Gauss-Newton (GN) method and l1-regularized method, which takes external forces and displacements of observable nodes as inputs. A series of numerical simulations and physical hydrogel phantom experiments were conducted. The results of simulation and physical experiments show that the Young's modulus and equivalent spring constraint boundary conditions identified by the proposed method agree well with their setup true values.

A novel material point method (MPM) based needle-tissue interaction model.

Needle-tissue interaction model is essential to tissue deformation prediction, interaction force analysis and needle path planning system. Traditional FEM based needle-tissue interaction model would encounter mesh distortion or continuous mesh subdivision in dealing with penetration, in which the computational instability and poor accuracy could be introduced. In this work, a novel material point method (MPM) is applied to establish the needle-tissue interaction model which is suitable to handle the discontinuous penetration problem. By integrating a hyperelastic material model, the tissue deformation and interaction force can be solved simultaneously and independently. A testbed of needle insertion into a Polyvinyl alcohol (PVA) hydrogel phantom was constructed to validate both tissue deformation and interaction force. The results showed the experimental data agrees well with the simulation results of the proposed model.

Independent roles of CGRP in cardioprotection and hemodynamic regulation in ischemic postconditioning.

Calcitonin gene-related peptide (CGRP) may participate in ischemic post-conditioning (IPost) attenuating myocardial ischemia/reperfusion injury. However, the molecular mechanism underlying the effect of CGRP is still elusive. In this study, we evaluated the difference in hemodynamics, infarct size and CGRP in myocardium and serum of rats after acute myocardial ischemia/reperfusion with and without IPost. A specific antagonist of CGRP receptor, CGRP8-37 was employed to testify the role of endogenous CGRP in IPost. The underlying mechanism was investigated by evaluation of the effect of CGRP on the changes in cytosolic reactive oxygen species, mitochondrial membrane potential and myocyte apoptosis induced by hypoxia/reoxygenation in cultured cardiomyocytes of neonatal rats. The results showed that IPost significantly upgraded CGRP in myocardium and serum with reduced infarct size, independent of the reductions in blood pressures observed in this study. The effects were significantly reversed by CGRP8-37, indicating an involvement of intrinsic CGRP. It was further demonstrated that CGRP effectively reversed the hypoxia/reoxygenation-induced reduction of mitochondrial membrane potential and attenuated the increases of cytosolic reactive oxygen species and cardiomyocyte apoptosis. The findings may demonstrate that CGRP mediates the cardioprotective and vasoactive effects of IPost. Homeostasis of cytosolic reactive oxygen species and mitochondrial membrane potential may be underlying the cardioprotective effect of CGRP.

Preservation of CGRP in myocardium attenuates development of cardiac dysfunction in diabetic rats.

BACKGROUND: Calcitonin gene-related peptide (CGRP) plays an important role in cardiovascular regulation, which was found reduced in serum of diabetic patients. To test the hypothesis that lack of CGRP in myocardium is associated with diabetic cardiac dysfunction, which may be improved by preservation of CGRP in diabetic rats. METHODS AND RESULTS: Diabetes was induced in male Sprague-Dawley rats by streptozotocin (50mg/kg). Two groups of the diabetic rats, one fed with standard laboratory chew and another with the laboratory food plus hot pepper (containing 0.0174% of capsaicin), to stimulate production and release of CGRP. Cardiac functions were evaluated by measurements of intraventricular pressures after 8weeks of development of diabetes. Transient receptor potential vanilloid type 1 (TRPV1), CGRP, ß1-adreneregic receptor and norepinephrine were analyzed. Significantly lower levels of TRPV1 and CGRP were detected in the thoracic dorsal root ganglia (DRG) and myocardium of the diabetic animals, along with significant decline in left ventricular systolic pressure (by 24%) and heart rate (by 25%) and increase of the end-diastolic pressure (by 83%) with obvious reduction of CGRP in the DRG, by 41%, the myocardium (by 30%) and the serum (by 20%). The cardiac performance, the TRPV1 and the CGRP in the diabetic animals fed with hot pepper were well preserved. No any significant change in ß1-adreneregic receptor and norepinephrine was detected. CONCLUSION: The findings may suggest a novel mechanism underlying diabetic cardiac dysfunctions via impairing TRPV1-CGRP pathway in myocardium. Preservation of the TRPV1-CGRP mechanism may prevent the development of cardiac dysfunction in diabetes.