Lycium barbarum L. Polysaccharide (LBP) Reduces Glucose Uptake via Down-Regulation of SGLT-1 in Caco2 Cell.

Lycium barbarum L. polysaccharide (LBP) is prepared from Lycium barbarum L. (L. barbarum), which is a traditional Chinese medicine. LPB has been shown to have hypoglycemic effects. In order to gain some mechanistic insights on the hypoglycemic effects of LBP, we investigated the uptake of LBP and its effect on glucose absorption in the human intestinal epithelial cell line Caco2 cell. The uptake of LBP through Caco2 cell monolayer was time-dependent and was inhibited by phloridzin, a competitive inhibitor of SGLT-1. LPB decreased the absorption of glucose in Caco2 cell, and down-regulated the expression of SGLT-1. These results suggest that LBP might be transported across the human intestinal epithelium through SGLT-1 and it inhibits glucose uptake via down-regulating SGLT-1.

Aquaporin plays an important role in mediating chloroplastic CO2 concentration under high-N supply in rice (Oryza sativa) plants.

Our previous studies demonstrated that chloroplastic CO2 concentration (Cc) is not sufficient under high-nitrogen (N) supply in rice plants. In this research, we studied how aquaporins- (AQPs) mediated Cc under different N-supply levels. A hydroponic experiment was conducted in a greenhouse with three different N levels (low N, 0.71 mM; intermediate N, 2.86 mM; and high N, 7.14 mM) in a rice cultivar (Oryza sativa cv. Shanyou 63) and with an ospip1;1 mutant (Oryza sativa cv. Nipponbare). The photosynthetic nitrogen-use efficiency (PNUE) decreased with increasing leaf-N content. Under high-N supply, the estimated Cc was significantly lower than the theoretical Cc and the specific Rubisco activity (carboxylation efficiency/Rubisco content, CE/Rubisco) decreased, because of a decrease of relative CO2 diffusion conductance (total CO2 diffusion conductance/leaf-N content, gt /N) in mesophyll cells. Real Time Quantitative PCR (Q-RT-PCR) showed that most OsPIP1s and OsPIP2s expression were downregulated under the high-N supply. Furthermore, Cc and gm decreased in the ospip1;1 mutant line compared with that of the wild-type plant. It was concluded that under high-N supply, the decreased PNUE was associated with non-sufficient Cc, mediated by AQP in mesophyll conductance.

[Study on Electrocardiogram Signal De-noising Methods Based on Ensemble Empirical Mode Decomposition Decomposed by White Noise].

Ensemble empirical mode decomposition(EEMD)is an effective method for non-stationary signal analysis,such as electrocardiogram(ECG)signals.However,the precision and correctness of EEMD are affected by the two parameters,ratio of the added noise and ensemble number.The values of two parameters are set relying on experience and lacking of adaptability for uncertain signals.In order to solve these problems,we proposed a method based on white noise decomposed by EEMD in the present study shown in this paper.Empirical mode decomposition(EMD)was applied to decompose the signal to different intrinsic mode functions(IMFs)in the de-noising process.The white noise IMFs were selected to constitute high frequency part based on the character that the product of the energy density of white noise and its average period tended to be a constant.Then the two parameters of EEMD were adaptively obtained according to the criterion which was used to avoid modal aliasing.Experimental results showed that the method was an effective one for ECG signal de-noising.

[Regulatory effect of electroacupuncture on heart and stomach of rats].

OBJECTIVE: To explore different regulatory effects of electroacupuncture (EA) at the same acupoint on the heart and the stomach. METHODS: Eighty male SD rats were randomly divided into eight groups equally, i.e., the Neiguan (PC6) group, the Quchi (LI11) group, the Tianshu (ST25) group, the Danzhong (RN17) group, the Zusanli (ST36) group, the Sanyinjiao (SP6) group, the Xinshu (BL15) group, and the Weishu (BL21) group, 10 in each group. The regulatory effects of EA (2/15 Hz, 3 mA, 2 min) at different acupoints on the gastric motility (intragastric pressure) and the cardiac function (the left ventricular pressure) were observed. The mean values of effect of two-min pre-EA and after-EA were compared. RESULTS: Compared with the pre-EA in the same group, the left ventricular pressure decreased in the Neiguan (PC6) group, the Quchi (LI11) group, the Danzhong (RN17) group, the Sanyinjiao (SP6) group, and the Xinshu (BL15) group (P <0.05). The intragastric pressure increased in the Quchi (LI11) group, the Zusanli (ST36) group, the Sanyinjiao (SP6) group, and the Xinshu (BL15) group, while it decreased in the Tianshu (ST25) group, the Danzhong (RN17) group, and the Weishu (BL21) group (P <0.05). The difference of the left ventricular pressure was sequenced from high to low as Xinshu (BL15) >Danzhong (RN17) >Neiguan (PC6) >Sanyinjiao (SP6) >Quchi (LI11). The difference of the intragastric pressure was sequenced from high to low as Tianshu (ST25) >Weishu (BL21) > Xinshu (BL15) > Danzhong (RN17) > Zusanli (ST36) > Sanyinjiao (SP6) > Quchi (LI11). CONCLUSIONS: EA at the same acupoint (2/15 Hz, 3 mA) showed different regulatory effects on the heart and stomach. There existed some difference in the direction and size due to the acupoint location, meridians, dominant nerve segment or relating organs. A fixed effect direction to the specific target was also shown.

Effect of electroacupuncture on neuronal programmed necrosis by regulating RIP1/RIP3/MLKL pathway in rats with cerebral ischemia reperfusion injury. / 电针调节RIP1/RIP3/MLKLé€šè·¯å¯¹è„‘ç¼ºè¡€å†çŒæ³¨æŸä¼¤å¤§é¼ ç¥žç»å ƒç¨‹åºæ€§åæ­»çš„å½±å“.

OBJECTIVES: To investigate the neuroprotective effect of electroacupuncture (EA) at "Quchi"(LI11) and "Zusanli"(ST36) in the rats with cerebral ischemia reperfusion injury and its influence on programmed necrosis of cerebral cortical neurons. METHODS: Sixty male SD rats were randomly divided into sham-operation group, model group, EA group and inhibitor group, with 15 rats in each group. Left middle cerebral artery occlusion model was established using the modified thread embolism method. In the sham-operation group, the carotid artery was exposed and dissociated in each rat. EA was applied to "Quchi"(LI11) and "Zusanli"(ST36) on the right side for 30 min each time, once daily for 7 days in the rats of the EA group. The rats in the inhibitor group were intraperitoneally injected with norstatin-1 (0.6 mg/kg) for consecutive 7 days. The neurological deficit score of rats in each group was observed. HE staining was adopted to detect the degree of pathological damage of the cerebral cortex in the infarction area. Using TUNEL staining, the apoptosis of cortical neurons in the infarction area was determined；the contents of tumor necrosis factor α (TNF-α), interleukin (IL)-1ß and IL-6 were detected by ELISA；the mRNA and protein expression of the receptor interacting protein-1 (RIP1), the receptor interacting protein-3 (RIP3) and the substrate mixed lineage kinase like protein (MLKL) were detected by fluorescence quantitative PCR and Western blot, respectively. RESULTS: In comparison with the sham-operation group, the neurological deficit score in the model group was higher(P<0.01)；HE staining showed that there was the pathological damage in the infarction area；the neuron apoptosis rate, the contents of TNF-α, IL-1ß and IL-6, and the mRNA and protein expressions of RIP1, RIP3 and MLKL increased(P<0.01) in the model group. In the EA group, the neurological deficit score was reduced(P<0.01)；HE staining showed that the pathological damage was ameliorated in the infarction area；the neuron apoptosis rate, the contents of TNF-α, IL-1ß and IL-6, and the mRNA and protein expressions of RIP1, RIP3, MLKL decreased(P<0.05, P<0.01) when compared with those in the model group. CONCLUSIONS: EA can attenuate cerebral ischemia reperfusion injury and display its neuroprotective effect probably through inhibiting programmed necrosis of cerebral cortical neurons in the rats.

The progress of autoimmune hepatitis research and future challenges.

Autoimmune hepatitis (AIH) is a chronic liver inflammatory disease with various immune system manifestations, showing a global trend of increased prevalence. AIH is diagnosed through histological abnormalities, clinical manifestations, and biochemical indicators. The biochemical markers involve interfacial hepatitis, transaminase abnormalities, positive autoantibodies, etc. Although AIH pathogenesis is unclear, gene mutations and immunological factors could be the leading factors. AIH usually presents as a chronic liver disease and sometimes as acute hepatitis, making it challenging to distinguish it from drug-related hepatitis due to similar clinical symptoms. Normalizing transaminases and serum IgG levels is essential in assessing the remission status of AIH treatment. Glucocorticoids and azathioprine are the first-line AIH treatment, with lifelong maintenance therapy in some patients. The quality of life and survival can be improved after appropriate treatment. However, certain limitations jeopardize the quality of treatment, including long treatment cycles, side effects, poor patient compliance, and inability to inhibit liver fibrosis and cirrhosis. Accurate AIH animal models will help us understand the pathophysiology of the disease while providing fresh perspectives for avoiding and treating AIH. This review will help us understand AIH better, from the cellular and molecular causes to the clinical features, and will provide insight into new therapy techniques with fewer side effects.

Chloroplast downsizing under nitrate nutrition restrained mesophyll conductance and photosynthesis in rice (Oryza sativa L.) under drought conditions.

The phenomenon whereby ammonium enhances the tolerance of rice seedlings (Oryza sativa L., cv. 'Shanyou 63' hybrid indica China) to water stress has been reported in previous studies. To study the intrinsic mechanism of biomass synthesis related to photosynthesis, hydroponic experiments supplying different nitrogen (N) forms were conducted; water stress was simulated by the addition of polyethylene glycol. Water stress decreased leaf water potential (Ψ(leaf)) under nitrate nutrition, while it had no negative effect under ammonium nutrition. The decreased Ψ(leaf) under nitrate nutrition resulted in chloroplast downsizing and subsequently decreased mesophyll conductance to CO(2) (g(m)). The decreased g(m) and stomatal conductance (g(s)) under nitrate nutrition with water stress restrained the CO(2) supply to the chloroplast and Rubisco. The relatively higher distribution of leaf N to Rubisco under ammonium nutrition might also be of benefit for photosynthesis under water stress. In conclusion, chloroplast downsizing induced a decline in g(m), a relatively higher decrease in g(s) under nitrate nutrition with water stress, restrained the CO(2) supply to Rubisco and finally decreased the photosynthetic rate.

Drought-induced root aerenchyma formation restricts water uptake in rice seedlings supplied with nitrate.

Previous studies demonstrated that ammonium nutrition results in higher water uptake rate than does nitrate nutrition under water stress, and thus enhances the tolerance of rice plants to water stress. However, the process by which water uptake is related to nitrogen form under water stress remains unknown. A hydroponic experiment with simulated water stress induced by polyethylene glycol (PEG6000) was conducted in a greenhouse to study the relationship between root aerenchyma formation and water uptake rate, such as xylem sap flow rate and hydraulic conductance, in two different rice cultivars (cv. 'Shanyou 63' hybrid indica and cv. 'Yangdao 6' indica, China). The results showed that root aerenchyma tissue increased in water-stressed plants of both cultivars fed by nitrate. No significant difference was found in root hydraulic conductivity and/or xylem sap flow rate between the two rice cultivars fed by ammonium regardless of water status, whereas these parameters decreased significantly in water-stressed plants fed by nitrate. It was concluded that aerenchyma that formed in the root cortex impeded the radial transport of water in the root cylinder and decreased water uptake in water-stressed rice plants fed by nitrate. Water transport occurred mainly through Hg-sensitive water channels in rice roots supplied with ammonium.

Self-assembly of phospholipid-PEG coating on nanoparticles through dual solvent exchange.

We coated nanoparticles including iron oxide nanoparticles and quantum dots with phospholipid-PEG using the newly developed dual solvent exchange method and demonstrated that, compared with the conventional film hydration method, the coating efficiency and quality of coated nanoparticles can be significantly improved. A better control of surface coating density and the amount of reactive groups on nanoparticle surface is achieved, allowing conjugation of different moieties with desirable surface concentrations, thus facilitating biomedical applications of nanoparticles.

Neuroprotective, Anti-inflammatory Effect of Furanochrome, Visnagin Against Middle Cerebral Ischemia-Induced Rat Model.

In recent years, the medical field had significantly progressed to a greater extent which was evidenced with increased life expectancy and decreased mortality rate. Due to the growth of medical field, numerous communicable diseases are prevented and eradicated, whereas the non-communicable disease incidence has been increased globally. One such non-communicable disease which threatens the global population is stroke. Stroke tends to be the second leading cause of death and disability in older population. In lower- and middle-income countries, increased incidence rate of stroke was also evidenced in younger population which is alarming. Lifestyle changes, poor physical activity, stress, consumption of alcohol, oral contraception, and smoking tend to be the causative agents of stroke. Since thrombus formation is the major pathology of stroke, drugs were targeted to thrombolysis. Currently thrombolytic, antiplatelet, and anticoagulant therapies were given for the stroke patients. But the recovery rate of stroke patients with available drugs is very slow. Hence, it is a need of today to discover a drug with increased recovery rate and decreased or nil side effects. Phytochemicals are the best options to treat such non-communicable chronic diseases. Visnagin is one such compound which is used to regulate blood pressure, treat kidney stones, tumors of bile duct, renal colic, and whooping cough. It possesses anti-inflammatory, neuroprotective, and cardioprotective properties; it was also proven to treat epileptic seizures. In this study, the anti-ischemic effect of a furanochrome visnagin was assessed in in vivo rat model. Middle cerebral ischemic/reperfusion was induced in healthy male Sprague Dawley rats and treated with different concentrations of visnagin. The neuroprotective effect of visnagin against cerebral ischemia-induced rats was assessed by analyzing the neurological score, brain edema, infract volume, and Evans blue leakage. The anti-inflammatory property of visnagin was assessed by quantifying proinflammatory cytokines in serum and brain tissues of cerebral ischemia-induced rats. Prostaglandin E-2, COX-2, and NFκ-ß were estimated to assess the anti-ischemic effect of visnagin. Histopathological analysis with H&E staining was performed to confirm the neuroprotective effect of visnagin against cerebral ischemia. Our results authentically confirm that visnagin has prevented the inflammation in brain region of cerebral ischemia-induced rats. The neurological scoring and the quantification of PGE-2, COX-2, and NFκ-ß prove the anti-ischemic effect of visnagin. Furthermore, the histopathological analysis of hippocampal region provides evidence to the neuroprotective effect of visnagin against cerebral ischemia. Overall, our study confirms visnagin as a potent alternative drug to treat stroke.

[Effect of electroacupuncture of Governor Vessel on expression of GAD67 and GABA-T in cerebral cortex of rats with post-stroke limb spasticity].

OBJECTIVE: To observe the effect of electroacupuncture (EA) of Governor Vessel (GV) on the expressions of glutamate decarboxylase 67 (GAD67) and γ-aminobutyric acid transaminase (GABA-T) in the cerebral cortex of rats with post-stroke limb spasticity, so as to explore its mechanism underlying improvement of limb spasticity. METHODS: Twenty four male SD rats were randomly and equally divided into control, sham operation, model, and EA groups. The cerebral ischemia model was established by occlusion of the middle cerebral artery (MCAO). EA (100 Hz, 1-3 mA) was applied to "Dazhui"(GV14), "Jizhong"(GV6) and "Houhui"( anteromedial of transverse process of the sixth lumbar vertebra) for 30 min, once daily for 7 consecutive days. The neurologic deficit score (0-5 points) was evaluated according to Zea Longa's method, and the muscular tension severity (0-5 points) was assessed according to the modified Ashworth muscle tone rating scale, and the tension signals of the quadriceps ferroris of the affected limb were recorded using tonotransducer and BL-420F electrophysiological recorder. The expression levels of GAD67 and GABA-T proteins and mRNAs in the cerebral cortex were detected by immunohistochemistry, fluorescence quantitative real-time PCR and Western blot, separately. RESULTS: After modeling, the neurological deficit score, muscle tone score, and the expression levels of GABA-T mRNA and protein in cerebral cortex were significantly increased (P<0.01, P<0.05), tension signal value and the expression levels of GAD67 mRNA and protein in cerebral cortex were significantly decreased (P<0.01) in the model group relevant to the control and sham operation groups. Following the intervention, the neurological deficit score, muscle tone score, and expression levels of GABA-T mRNA and protein in cerebral cortex were significantly decreased (P<0.01), tension signal value and the expression levels of GAD67 mRNA and protein in cerebral cortex were significantly increased (P<0.01, P<0.05) in the EA group in contrast to the model group. CONCLUSION: EA stimulation of Governor Vessel can ameliorate the limb spasticity symptom in MCAO rats, which may be associated with its functions in increasing the expressions of GAD67 protein and mRNA and inhibiting the expressions of GABA-T protein and mRNA, thereby playing the inhibitory role of GABA.

Efficacy of manual acupuncture, electro-acupuncture, and warm acupuncture for knee osteoarthritis: study protocol for a randomized controlled trial.

BACKGROUND: Acupuncture is one of the most popular complementary and alternative treatments for knee osteoarthritis (KOA). There are many methods of acupuncture in the treatment of KOA, and the effects are different. According to our clinical observations and researches, it is found that manual acupuncture (MA), electro-acupuncture (EA), and warm acupuncture (WA) are used more frequently in the treatment of KOA, and the curative effects are satisfactory. However, there is currently a lack of efficacy comparison of efficacy between different acupuncture treatments, as well as a lack of standardized clinical research on the acupuncture treatment of KOA. Therefore, we will carry out a high-quality clinical randomized controlled trial to research the effect laws of MA, EA, and WA on KOA. METHODS/DESIGN: A total of 200 eligible participants with KOA will be randomly assigned to group A, B, C, or D in a ratio of 1:1:1:1. Patients in group A will receive MA, while those in group B, group C, and group D will be treated with EA, WA, and sham acupuncture (SA), respectively. Patients will be treated with acupuncture once a day, 30 min per session, 5 sessions per week for 4 weeks. The primary outcome is the change of Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) at week 4. The secondary outcomes include WOMAC, visual analog scale (VAS), Arthritis Quality of Life Measurement Scale Simplified Scale (AIMS2-SF), Beck Anxiety Inventory (BAI), Beck Depression Inventory (BDI), and Credibility/Expectancy Questionnaire. The evaluation will be performed at baseline and weeks 4, 8, and 12 respectively after randomization. DISCUSSION: This is a randomized controlled trial. We will observe the clinical effect of MA, EA, and WA on KOA to research the effect laws of these three acupuncture treatments on KOA and set up standardized treatment programs for acupuncture for KOA. TRIAL REGISTRATION: China Clinical Trials Registry ChiCTR2100049526. Registered on August 2, 2021.

Deep-learning image reconstruction for image quality evaluation and accurate bone mineral density measurement on quantitative CT: A phantom-patient study.

Background and purpose: To investigate the image quality and accurate bone mineral density (BMD) on quantitative CT (QCT) for osteoporosis screening by deep-learning image reconstruction (DLIR) based on a multi-phantom and patient study. Materials and methods: High-contrast spatial resolution, low-contrast detectability, modulation function test (MTF), noise power spectrum (NPS), and image noise were evaluated for physical image quality on Caphan 500 phantom. Three calcium hydroxyapatite (HA) inserts were used for accurate BMD measurement on European Spine Phantom (ESP). CT images were reconstructed with filtered back projection (FBP), adaptive statistical iterative reconstruction-veo 50% (ASiR-V50%), and three levels of DLIR(L/M/H). Subjective evaluation of the image high-contrast spatial resolution and low-contrast detectability were compared visually by qualified radiologists, whilst the statistical difference in the objective evaluation of the image high-contrast spatial resolution and low-contrast detectability, image noise, and relative measurement error were compared using one-way analysis of variance (ANOVA). Cohen's kappa coefficient (k) was performed to determine the interobserver agreement in qualitative evaluation between two radiologists. Results: Overall, for three levels of DLIR, 50% MTF was about 4.50 (lp/cm), better than FBP (4.12 lp/cm) and ASiR-V50% (4.00 lp/cm); the 2 mm low-contrast object was clearly resolved at a 0.5% contrast level, while 3mm at FBP and ASiR-V50%. As the strength level decreased and radiation dose increased, DLIR at three levels showed a higher NPS peak frequency and lower noise level, leading to leftward and rightward shifts, respectively. Measured L1, L2, and L3 were slightly lower than that of nominal HA inserts (44.8, 95.9, 194.9 versus 50.2, 100.6, 199.2mg/cm3) with a relative measurement error of 9.84%, 4.08%, and 2.60%. Coefficients of variance for the L1, L2, and L3 HA inserts were 1.51%, 1.41%, and 1.18%. DLIR-M and DLIR-H scored significantly better than ASiR-V50% in image noise (4.83 ± 0.34, 4.50 ± 0.50 versus 4.17 ± 0.37), image contrast (4.67 ± 0.73, 4.50 ± 0.70 versus 3.80 ± 0.99), small structure visibility (4.83 ± 0.70, 4.17 ± 0.73 versus 3.83 ± 1.05), image sharpness (3.83 ± 1.12, 3.53 ± 0.90 versus 3.27 ± 1.16), and artifacts (3.83 ± 0.90, 3.42 ± 0.37 versus 3.10 ± 0.83). The CT value, image noise, contrast noise ratio, and image artifacts in DLIR-M and DLIR-H outperformed ASiR-V50% and FBP (P<0.001), whilst it showed no statistically significant between DLIR-L and ASiR-V50% (P>0.05). The prevalence of osteoporosis was 74 (24.67%) in women and 49 (11.79%) in men, whilst the osteoporotic vertebral fracture rate was 26 (8.67%) in women and (5.29%) in men. Conclusion: Image quality with DLIR was high-qualified without affecting the accuracy of BMD measurement. It has a potential clinical utility in osteoporosis screening.

Case Report: Venoarterial Extracorporeal Membrane Oxygenation Support for Caowu-Induced Cardiac Arrest.

Introduction: Caowu, the main root of the Aconitum plant, is widely used in China. Aconitine is the main toxic component of Aconitum, which can cause a variety of malignant arrhythmias and lead to death. Four patients who developed malignant arrhythmia after drinking medicinal wine containing Caowu were reported in this study. Cardiac arrest occurred soon after symptom onset. All patients received venoarterial extracorporeal membrane oxygenation (VA-ECMO) support after conservative medical treatment had failed. Patients who were directly transferred to our hospital received VA-ECMO support earlier than patients who were first treated at a local hospital. One patient received hemoperfusion in the emergency room before VA-ECMO support; the other three patients began hemoperfusion after VA-ECMO treatment. Surviving patients who received VA-ECMO earlier after symptom onset showed no obvious neurological complications. The patient who received a longer cardiopulmonary resuscitation time but received hemoperfusion before VA-ECMO had mild neurological complications. The mortality rate was 25% (1 of 4 patients). Two patients had thrombotic complications in venous vessels. Conclusions: Cardiogenic shock due to refractory ventricular tachycardia caused by aconitine is lethal. Conservative supportive treatment did not provide a short-term antiarrhythmic effect and the cardiogenic shock was not well controlled. VA-ECMO treatment combined with hemoperfusion is promising temporary support to successfully treat aconitine-induced cardiogenic shock caused by refractory ventricular tachycardia.

[Effects of organic manure partial substitution for chemical fertilizer on the photosynthetic rate, nitrogen use efficiency and yield of rice]. / æœ‰æœºè‚¥æ›¿ä»£éƒ¨åˆ†åŒ–è‚¥å¯¹æ°´ç¨»å ‰åˆé€ŸçŽ‡ã€æ°®ç´ åˆ©ç”¨çŽ‡å’Œäº§é‡çš„å½±å“.

Rational application of organic fertilizers is an effective approach to improve soil fertility, crop yield, and zero growth of chemical fertilizer in agricultural production. The rice variety 'Shennong9816' was planted in Shenyang, Liaoning Province, under seven different treatments: zero nitrogen fertilizer (CK), low nitrogen, 150 kg·hm-2(LN), medium nitrogen, 240 kg·hm-2 (MN), high nitrogen, 330 kg·hm-2(HN), medium nitrogen with replacement of chemical N by 10% organic manure (OMN10), medium nitrogen with replacement of chemical N by 20% organic manure (OMN20), and medium nitrogen with replacement of chemical N by 30% organic manure (OMN30). The effects of different treatments on photosynthetic rate, nitrogen absorption, nitrogen use efficiency, and yield were examined and the optimal fertilization scheme was determined. The results showed that the photosynthetic rate, biomass and yield were increased with the increases of nitrogen application rate, while the nitrogen use efficiency was decreased significantly. Compared with the MN treatment, the photosynthetic rate of OMN10 and OMN20 in filling stage was increased by 22.9% and 9.9%, respectively. The yield of OMN20 was increased by 3.8% compared to that of MN. The nitrogen agronomic efficiency and physiological efficiency of OMN20 were significantly improved by 8.1% and 13.3%, respectively. Moreover, the nitrogen agronomic efficiency and physiological efficiency of OMN20 were improved by 27.2% and 37.2% compared with the HN treatment. Thus, we concluded that the organic fertilizer replacement treatment could conserve soil fertility, achieve high yield and high nitrogen use efficiency, while reduce chemical nitrogen fertilizer application. The OMN20 treatment was recommended as a fertilizer application model due to its superior performance among the seven treatments.

Reactivity of nitric oxide with the [4Fe-4S] cluster of dihydroxyacid dehydratase from Escherichia coli.

Although the NO (nitric oxide)-mediated modification of iron-sulfur proteins has been well-documented in bacteria and mammalian cells, specific reactivity of NO with iron-sulfur proteins still remains elusive. In the present study, we report the first kinetic characterization of the reaction between NO and iron-sulfur clusters in protein using the Escherichia coli IlvD (dihydroxyacid dehydratase) [4Fe-4S] cluster as an example. Combining a sensitive NO electrode with EPR (electron paramagnetic resonance) spectroscopy and an enzyme activity assay, we demonstrate that NO is rapidly consumed by the IlvD [4Fe-4S] cluster with the concomitant formation of the IlvD-bound DNIC (dinitrosyl-iron complex) and inactivation of the enzyme activity under anaerobic conditions. The rate constant for the initial reaction between NO and the IlvD [4Fe-4S] cluster is estimated to be (7.0+/-2.0)x10(6) M(-2) x s(-1) at 25 degrees C, which is approx. 2-3 times faster than that of the NO autoxidation by O2 in aqueous solution. Addition of GSH failed to prevent the NO-mediated modification of the IlvD [4Fe-4S] cluster regardless of the presence of O2 in the medium, further suggesting that NO is more reactive with the IlvD [4Fe-4S] cluster than with GSH or O2. Purified aconitase B [4Fe-4S] cluster from E. coli has an almost identical NO reactivity as the IlvD [4Fe-4S] cluster. However, the reaction between NO and the endonuclease III [4Fe-4S] cluster is relatively slow, apparently because the [4Fe-4S] cluster in endonuclease III is less accessible to solvent than those in IlvD and aconitase B. When E. coli cells containing recombinant IlvD, aconitase B or endonuclease III are exposed to NO using the Silastic tubing NO delivery system under aerobic and anaerobic conditions, the [4Fe-4S] clusters in IlvD and aconitase B, but not in endonuclease III, are efficiently modified forming the protein-bound DNICs, confirming that NO has a higher reactivity with the [4Fe-4S] clusters in IlvD and aconitase B than with O2 or GSH. The results suggest that the iron-sulfur clusters in proteins such as IlvD and aconitase B may constitute the primary targets of the NO cytotoxicity under both aerobic and anaerobic conditions.

Cumulative oxygen deficit is a novel predictor for the timing of invasive mechanical ventilation in COVID-19 patients with respiratory distress.

BACKGROUND AND OBJECTIVES: The timing of invasive mechanical ventilation (IMV) is controversial in COVID-19 patients with acute respiratory hypoxemia. The study aimed to develop a novel predictor called cumulative oxygen deficit (COD) for the risk stratification. METHODS: The study was conducted in four designated hospitals for treating COVID-19 patients in Jingmen, Wuhan, from January to March 2020. COD was defined to account for both the magnitude and duration of hypoxemia. A higher value of COD indicated more oxygen deficit. The predictive performance of COD was calculated in multivariable Cox regression models. RESULTS: A number of 111 patients including 80 in the non-IMV group and 31 in the IMV group were included. Patients with IMV had substantially lower PaO2 (62 (49, 89) vs. 90.5 (68, 125.25) mmHg; p < 0.001), and higher COD (-6.87 (-29.36, 52.38) vs. -231.68 (-1040.78, 119.83) mmHg·day) than patients without IMV. As compared to patients with COD < 0, patients with COD > 30 mmHg·day had higher risk of fatality (HR: 3.79, 95% CI [2.57-16.93]; p = 0.037), and those with COD > 50 mmHg·day were 10 times more likely to die (HR: 10.45, 95% CI [1.28-85.37]; p = 0.029). CONCLUSIONS: The study developed a novel predictor COD which considered both magnitude and duration of hypoxemia, to assist risk stratification of COVID-19 patients with acute respiratory distress.

Nitric oxide-induced bacteriostasis and modification of iron-sulphur proteins in Escherichia coli.

The nitric oxide (NO) cytotoxicity has been well documented in bacteria and mammalian cells. However, the underlying mechanism is still not fully understood. Here we report that transient NO exposure effectively inhibits cell growth of Escherichia coli in minimal medium under anaerobic growth conditions and that cell growth is restored when the NO-exposed cells are either supplemented with the branched-chain amino acids (BCAA) anaerobically or returned to aerobic growth conditions. The enzyme activity measurements show that dihydroxyacid dehydratase (IlvD), an iron-sulphur enzyme essential for the BCAA biosynthesis, is completely inactivated in cells by NO with the concomitant formation of the IlvD-bound dinitrosyl iron complex (DNIC). Fractionation of the cell extracts prepared from the NO-exposed cells reveals that a large number of different protein-bound DNICs are formed by NO. While the IlvD-bound DNIC and other protein-bound DNICs are stable in cells under anaerobic growth conditions, they are efficiently repaired under aerobic growth conditions even without new protein synthesis. Additional studies indicate that L-cysteine may have an important role in repairing the NO-modified iron-sulphur proteins in aerobically growing E. coli cells. The results suggest that cellular deficiency to repair the NO-modified iron-sulphur proteins may directly contribute to the NO-induced bacteriostasis under anaerobic conditions.

[Effect of bismuth glycyrrhizate on experimental gastric ulcers and its mechanisms].

OBJECTIVE: To investigate the ulcer-preventive effect of bismuth glycyrrhizate on experimental gastric ulcer and its mechanisms. METHOD: Three kinds of model animals with experimental gastric ulcer were established and gastric mucosal injuries were induced by pyloric ligation in rats, applying ethanol in rats and imposing stress in mice, respectively. The rats were divided into experimental groups treated with bismuth glycyrrhizat 700, 350, 175 mg kg(-1), positive control group treated with cimetidine (200 mg kg(-1), and negative control group treated with 0.1% EDTA. The mice were divided into experimental groups treated with bismuth glycyrrhiza 980, 490, 250 mg kg(-1). The gastric ulcer index, gastric juice volume, acidity, pepsin activity, the level of nitric oxide (NO) in serum and the level of prostaglandin E2 in gastric tissue were measured in rats. RESULT: Bismuth glycyrrhizate was shown to be able to reduce the gastric juice volume, acidity and pepsin activity as well as gastric ulcer index. It could increase the content of NO in serum and the content of prostaglandin E2 in gastric tissue. CONCLUSION: The bismuth glycyrrhizate has antiulcer effect in rats.