Changes in erythrocyte membrane ATPases and plasma lipid peroxides in upper abdominal surgery under intravenous procaine-balanced anesthesia

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AN AB INITIO STU DY ON THE CORELATION BETWEEN THE ABSOLUTE CONFIGURATION AND THE CD SPECTRA OF ORGANIC PEROXIDES

Correlation between the absolute configuration and the CD spectra of organic peroxides was studied by ab initio method with a mo- d el moleeule CH_3-O-O-CH_3.For P form when 0°≤θ(twist angle of C-O-O-C) <90°, there is positive Cotton effect;when 90°<θ≤180°, there is nega- tive Cotton effect;the curve is bisignate at θ=90°.

Relative Explosive Strength of Some Explosive Mixtures Containing Urea and/or Peroxides

Several mixtures,based on urea derivatives and some inorganic oxidants,including also alumina,were studied by means of ballistic mortar techniques with TNT as the reference standard.The detonation pressure(P),detonation velocity(D),detonation energy(Q),and volume of gaseous product at standard temperature and pressure(STP),V,were calculated using EXPLO5V6.3 thermochemical code.The performance of the mixtures studied was discussed in relation to their thermal reactivity,determined by means of differential thermal analysis(DTA).It is shown that the presence of hydrogen peroxide in the form of its complex with urea(i.e.as UHP)has a positive influence on the explosive strength of the corresponding mixtures which is linked to the hydroxy-radical formation in the mixtures during their initiation reaction.These radicals might initiate(at least partially)powdered aluminum into oxidation in the CJ plane of the detonation wave.Mixtures containing UHP and magnesium are dangerous because of potential auto-ignition.

Level of lipid peroxides and cuprozinc superoxide dismutase in gastric mucosa and serum of gastrectomized patients

The level of lipid peroxides (LPO) and copper-zinc containing superoxide dismutase (SOD-Ⅰ) in the gastric mucosa and serum was determined in 141 samples from 25 patients after con-ventional subtotal gastrectomy (11 cases of Billroth Ⅰ and 14 cases of Billroth Ⅱ) and 11 patientsafter pylorus and antroseromuscular flap preserving gastrectomy (PAFPG).Those of 11 normal subjects were examined likewise to serve as control.It was found that:(1) The average LPO levelwas much higher and the average SOD-Ⅰ level much lower in the gastric mucosa of the patientsafter conventional subtotal gastrectomy especially the Billroth Ⅱ type than in that of those afterPAFPG.(2) In 36 specimens of stump mucosa,the average LPO level was significantly higher inthe tissue around the anastomotic ring than in that of the body of the stump;no marked differ-ence of SOD-Ⅰ level between the 2 was revealed.(3) The LPO value in the stump mucosa waspositively correlated to and the SOD-Ⅰ value negatively correlated to the pH value of gastric juice.These rindings suggest that the reation of oxygen free radicals in the stump mucosa may be influ-enced by the intragastric pH or by the type of digestive continuity reconstruction,and that thereaction of oxygen free radicals especially the lipid peroxidation may play a role in the pathogenesisof the lesions in the anastomotic stoma.

Changes in erythrocyte membrane ATPase and plasma lipid peroxides during perioperative period

Changes in erythrocyte membrane ATPases and plasma lipid peroxides（LPO） were studiedperioperatively in 15 abdominal surgical patients under intravenous procaine-balanced anesthesia.The resultsrevealed that erythrocyte membrne Na+-K+ATPase,Mg2+ATPase and Ca2+-Mg2+ATPase activities werenot significantly changed at 60～90 min after incision as compared with 30 min before anesthesia,but weredecreased markedly at 10 rain and 24 hours after completion of operation（P【0.01）.Plasma LPO wereincreased significantly by 24 hours after surgery（P【0.01） following an initially marked but transientreduction.Plasma LPO changes were not correlated with erythrocyte membrane ATPase activities,r=-0.0396,-0.0097 and-0.4383 respeetively（P】0.05）.These correlations are suggested to be inducedby neuroendoerine responses after anesthesia and/or surgical trauma.

Amperometric Biosensors Sensitive to Organic Peroxides Based on Immobilization of Redox Organic Dyes and Horseradish Peroxidase in Polyester Ionomer Film

Simple and effective organic biosensors sensitive to organic peroxides such as 2 butanone per oxide and tertbutyl hydroperoxide are constructed by immobilizing a series of redox organic dyes and horseradish peroxidase in Eastman AQ polymer film. The organic dyes are methylene blue, methylene green, meldola blue, new methylene blue N and N methyl phenazine methosulphate. The biosensors display high sensitivity and fast response to tertbutyl hydroperoxide and 2 butanone peroxide because of high efficiency of electron transfer between immobilized horseradish peroxidase and the electrode via the redox organic dyes. The comparison of the biosensors employing different organic dyes is made in formal potential, linear range and response time.

Exogenous Vitamin K3 and Peroxides Can Alleviate Hypoxia in Bean Seedlings (<i>Phaseolus vulgaris</i>L.)

Oxygen limiting conditions are a common occurrence in root zones of most crop plants and can adversely affect nearly all aspects of plant growth and development including its survival. The objective of this study was to determine the effectiveness of a novel redox cycling agent, vitamin K3, and various peroxides including hydrogen peroxide, calcium peroxide and magnesium peroxide in alleviating the effects of hypoxia in bean seedlings grown in nutrient culture. All the anti-hypoxic agents including vitamin K3 had a positive impact on the overall growth of bean seedlings under hypoxic conditions, but their responses were variable depending on the concentration. With regard to shoot growth, vitamin K3 (5 μM) increased the leaf area significantly, by more than 58% over the hypoxic control plants and produced the highest stem fresh weight similar to calcium peroxide (20 μM) and magnesium peroxide (10 μM). In addition, the use of vitamin K3 resulted in the highest accumulation of chlorophyll (chla + chlb) in the leaves, an increase of nearly two-fold over the hypoxic control plants. Furthermore under hypoxia, calcium peroxide (20 μM) and magnesium peroxide (10 μM) produced the highest leaf biomass (FW) followed by vitamin K3. Vitamin K3 (1 μM) also favored root growth in bean seedlings under hypoxia;it produced the largest increase in root length and root biomass (DW) similar to calcium peroxide and magnesium peroxide. Based on the overall shoot and root growth response of bean seedlings to various anti-hypoxic substances under hypoxic conditions, calcium peroxide, magnesium peroxide and vitamin K3 performed better than hydrogen peroxide. These findings show that vitamin K3 and peroxide salts are effective in alleviating hypoxic stress in bean seedlings and also, further highlight their potential for dealing with hypoxia in wide ranging situations.

Apple Peel Biochemical Changes after Foliar Application of Combined Boron and Calcium II. Photosynthetic Pigments, Total Peroxides and Photochemical Efficiency

Understanding of the physiological effect of post-full-bloom foliar boron combined with calcium (B+Ca) on apple (Malus domestica) peel tissues is envisaged to give way to the unknown mode-of-action by which these mineral regimens suppress fruit sunburn-browning incidence in orchards. Promotion of this mineral approach among growers, as a certainly cheaper alternative to mitigate fruit sunburn-browning incidence in apple orchards necessitates clear elucidation of its mode-of-action. This study investigated peel photosynthetic pigments and total peroxides (as a measure of oxidative stress) in three apple cultivars, ‘Cripps Pink’, ‘Golden Delicious’ and ‘Granny Smith’ which were treated with four B+Ca treatments varying in levels of B and Ca as well as inclusion of zinc (Zn) in one treatment. Randomized complete block design experiments with five replications were conducted at commercial farms in Western Cape, South Africa. Significant (p < 0.05) treatment effect for major pigment aspects and total peroxides occurred in all cultivars, but with strong influence of cultivar and fruit age. For instance, effect of varying B, Ca and possible B+Ca duet-effect on photosynthetic pigments occurred in ‘Cripps Pink’, whereas the Zn-treatment was mainly responsible for significant treatment effects in both ‘Golden Delicious’ and ‘Granny Smith’ apples. Significant treatment effect for total peroxides occurred in ‘Cripps Pink’ and ‘Granny Smith’, yet significant interaction effect occurred with ‘Golden Delicious’, however, these significant results did not yield meaningful peel oxidative stress differences among the treatments. Foliar treatment differences in photochemical efficiency (Fv/Fm) were not significant. The study concludes with firm evidence that foliar B+Ca treatment composition has a significant effect on apple peel photosynthetic pigments depending on cultivar, and Zn is not desirable in the formulation of these treatments.

Adiabatic Decomposition of Two Kinds of Organic Peroxides by Accelerating Rate Calorimeter

The accelerating rate calorimeter was applied to study the thermal hazard of two kinds of organic peroxides, i.e. methyl ethyl ketone peroxide (MEKPO) and benzoyl peroxide (BPO). And their thermal decomposition characteristics were discussed. Meanwhile, thermal decomposition characteristics of MEKPO and BPO vvere compared. The result indicated that MEKPO is more sensitive to thermal effect than BPO. While once the thermal decomposition takes place. BPO will be more hazardous than MEKPO due to its serious pressure effect. Thermal kinetic analysis of these two kinds of organic peroxides was also taken, and the kinetic parameters for them were calculated. The study of thermal decomposition of MEKPO solution with different initial concentrations indicated that, the lower concentration MEKPO solution is, the higher onset temperature will be. And with the addition of organic solvent, it becomes more difficult for MEKPO to reach a thermal decomposition. Therefore, its thermal hazard is reduced.

NMR used to study the side-reactions between peroxides and antioxidants during the reactive extrusion process of the impact polypropylene

Side reaction pathways are observed to occur between antioxidants and peroxide during the processing of multiple resin grades mediated by controlled peroxide-induced degradation of impact polypropylene.In the present work,the reaction mechanism and main by-products between antioxidants and peroxides were investigated.The results demonstrate that peroxides greatly accelerate the decomposition reactions,and the free radicals formed from peroxide decomposition react with,for example,the antioxidant AO1010 to produce dehydrogenation of phenyl propionic unit(s)at the a position(cinnamic acid ester moiety),which generates a conjugated system leading to the increased color of the product.It is the first time to confirm the cinnamic acid moiety's existence and report its NMR data.Further,this work confirms the dehydrogenation mechanism by comparison with different sterically hindered phenolic antioxidants.It also systematically summarizes the oxidation and degradation mechanism of AO168 and AO1010 under air and peroxide environments,respectively.Based on present study,clear guidelines are obtained to improve the quality of polymeric products,especially the appearance and stability,during product development.

Effects of Organic Peroxides on the Curing Behavior of EVA Encapsulant Resin

Compounds of poly(ethylene-co-vinyl acetate) (EVA with vinyl acetate content 33%) with three different organic per- oxides, namely, dialkyl peroxide, peroxyester peroxide, and peroxyketal peroxide, were prepared with a twin screws extruder and a two-roll mixing mill. The cure behavior of the EVA compounds was analyzed from rheographs, which were obtained by a moving die rheometer (MDR) at various curing temperatures between 150?C to 170?C. The effects of organic peroxides on cure behavior were examined. The dynamic curing obtained by the torque rheometer provided sufficient experimental data to show that dialkyl peroxide is not suitable because it has a high half-life temperature and its by-products can discolor the final product. Peroxyester peroxide is good for curing at temperatures in the range of 150?C to 160?C, which accomplished an ultimate cure within 5 to 8 minutes. Also, the peroxyketal peroxide has higher performance, which decreased the optimum cure time to 3 minutes. The thermal decomposition mechanism of organic peroxide was applied to explain how the cure behavior is affected by generated free radicals.

Changes of Selenium Metabolism Glutathione Peroxidase Activity and Lipid Peroxides Content in Severely Scalding-injured Rats

The changes of sclenium metabolism, glutathione peroxidase activity and lipid peroxidescontent in the tissues of rats suffering from 30% TBSA full thickness scalding were observed in thefirst 7 days after injury. It was found that selenium content in the rat tissues decreased remarkably af-ter injury, which in turn resulted in serious reduction of glutathione peroxidasc activity and significantincrease of lipid peroxides in the scrum, crythrocytcs and liver. However the muscular tissue showedno significant changes. These facts imply that after burn injury, the body is in a state of selenium deficiency, the lossof selenium might be responsible for the reduction of anti - peroxidation ability of glutathioneperoxidase, and conscqucntly there is an increase of lipid peroxides in the tissues. Only the musculartissue is insensitive to lipid peroxidation. It is believed that the reduction of anti-peroxidation abilityof glutathione peroxidasc after bum injury might be one of the main causes to intensify, the injury re-suiting from free radicals.

Flavonoids Reduce Lipid Peroxides and Increase Glutathione Levels in Pooled Human Liver Microsomes (HLMs)

The effects of each of the flavonoids;genistein (G), quercetin (Q) and kaempferol (K) at several doses on lipid peroxides (LP) and reduced glutathione (GSH) in pooled human liver microsomes (HLMs) were investigated following the oxidative damage for 4, 6, 18 and 24 hr. HLMs (1 mg/ml) were exposed to each of the above flavonoids at 0, 5, 10, 15, 20 or 25 μM and incubated for the respective times as previously stated. Our hypothesis was that HLMs exposed to the flavonoids for the respective exposure times can decrease LP and increase GSH in HLMs to better cope with the oxidative stress. The results of our studies indicate that each of the flavonoids significantly (p < 0.01) decreased LP compared to their respective controls. The highest decrease in LP was observed for K followed by Q and G. Significant increases (p < 0.01) in GSH were observed for the flavonoid doses tested with the highest levels observed for Q for the 24-hr. incubation. The findings suggest that the flavonoids modulate oxidative stress in HLMs by decreasing LP and such decreases in LPs may be due to the increasing and or the replenished levels of GSH in the said cells to better cope with the oxidative stress.

Chiral Betaine-Mediated Asymmetric Peroxidation-Kinetic Resolution Cascade for the Synthesis of Optically Pure Peroxides

An array of natural products bearing chiral peroxide motifs display antitumor,anticancer,and antiparasitic activities.However,there are very few catalytic asymmetric syntheses of chiral peroxides.Moreover,effective catalysts for asymmetric catalytic peroxidations are limited to chiral amines.To further expand synthetic access to chiral peroxides,the development of new catalysts realizing catalytic asymmetric peroxidation is highly desirable yet challenging.We report here a catalytic asymmetric peroxidation of anα,β-unsaturated triflone-kinetic resolution cascade reaction,which furnishes chiral peroxides in greater than 99.9%ee.The realization of this cascade reaction resulted from the development of two betaines as novel catalysts for chiral peroxide synthesis;one betaine promoted enantioselective peroxidation ofα,β-unsaturated triflones via conjugate addition affording peroxides in 80-92%ee,while the other betaine catalyzed kinetic resolution of the newly generated chiral peroxides to further increase the ee to greater than 99.9%.

Ferroptosis and endoplasmic reticulum stress in ischemic stroke

Ferroptosis is a form of non-apoptotic programmed cell death,and its mechanisms mainly involve the accumulation of lipid peroxides,imbalance in the amino acid antioxidant system,and disordered iron metabolism.The primary organelle responsible for coordinating external challenges and internal cell demands is the endoplasmic reticulum,and the progression of inflammatory diseases can trigger endoplasmic reticulum stress.Evidence has suggested that ferroptosis may share pathways or interact with endoplasmic reticulum stress in many diseases and plays a role in cell survival.Ferroptosis and endoplasmic reticulum stress may occur after ischemic stroke.However,there are few reports on the interactions of ferroptosis and endoplasmic reticulum stress with ischemic stroke.This review summarized the recent research on the relationships between ferroptosis and endoplasmic reticulum stress and ischemic stroke,aiming to provide a reference for developing treatments for ischemic stroke.

Ferroptosis mechanism and Alzheimer's disease

Regulated cell death is a genetically determined form of programmed cell death that commonly occurs during the development of living organisms.This process plays a crucial role in modulating homeostasis and is evolutionarily conserved across a diverse range of living organisms.Ferroptosis is a classic regulatory mode of cell death.Extensive studies of regulatory cell death in Alzheimer’s disease have yielded increasing evidence that fe rroptosis is closely related to the occurrence,development,and prognosis of Alzheimer’s disease.This review summarizes the molecular mechanisms of ferroptosis and recent research advances in the role of ferro ptosis in Alzheimer’s disease.Our findings are expected to serve as a theoretical and experimental foundation for clinical research and targeted therapy for Alzheimer’s disease.

New insights on the role of chondroitin sulfate proteoglycans in neural stem cell–mediated repair in spinal cord injury

Extensive neurodegeneration is a hallmark of traumatic spinal cord injury (SCI) that underlies permanent sensorimotor and autonomic impairments (Alizadeh et al.,2019).Following the primary impact,the spinal cord undergoes a cascade of secondary injury mechanisms that are driven by disruption of the blood-spinal cord ba rrier,vascula r inju ry,glial reactivity,neu roinfla mmation,oxidative stress,lipid peroxidation,and glutamate excitotoxicity that culminate in neuronal and oligodendroglial cell death,demyelination,and axonal damage(Alizadeh et al.,2019).To achieve a meaningful functional recovery after SCI,regeneration of new neurons and oligodendrocytes and their successful growth and integration within the neural network are critical steps for reconstructing the damaged spinal cord tissue (Fischer et al.,2020).

Potential role and therapeutic implications of glutathione peroxidase 4 in the treatment of Alzheimer's disease

Alzheimer's disease is an age-related neurodegenerative disorder with a complex and incompletely understood pathogenesis. Despite extensive research, a cure for Alzheimer's disease has not yet been found. Oxidative stress mediates excessive oxidative responses, and its involvement in Alzheimer's disease pathogenesis as a primary or secondary pathological event is widely accepted. As a member of the selenium-containing antioxidant enzyme family, glutathione peroxidase 4 reduces esterified phospholipid hydroperoxides to maintain cellular redox homeostasis. With the discovery of ferroptosis, the central role of glutathione peroxidase 4 in anti-lipid peroxidation in several diseases, including Alzheimer's disease, has received widespread attention. Increasing evidence suggests that glutathione peroxidase 4 expression is inhibited in the Alzheimer's disease brain, resulting in oxidative stress, inflammation, ferroptosis, and apoptosis, which are closely associated with pathological damage in Alzheimer's disease. Several therapeutic approaches, such as small molecule drugs, natural plant products, and non-pharmacological treatments, ameliorate pathological damage and cognitive function in Alzheimer's disease by promoting glutathione peroxidase 4 expression and enhancing glutathione peroxidase 4 activity. Therefore, glutathione peroxidase 4 upregulation may be a promising strategy for the treatment of Alzheimer's disease. This review provides an overview of the gene structure, biological functions, and regulatory mechanisms of glutathione peroxidase 4, a discussion on the important role of glutathione peroxidase 4 in pathological events closely related to Alzheimer's disease, and a summary of the advances in small-molecule drugs, natural plant products, and non-pharmacological therapies targeting glutathione peroxidase 4 for the treatment of Alzheimer's disease. Most prior studies on this subject used animal models, and relevant clinical studies are lacking. Future clinical trials are required to validate the therapeutic effects of strategies targeting glutathione peroxidase 4 in the treatment of Alzheimer's disease.

Flower-like tin oxide membranes with robust three-dimensional channels for efficient removal of iron ions from hydrogen peroxide

Membrane technology has become the mainstream process for the production of electronic grade hydrogen peroxide(H_(2)O_(2)).But due to the oxidation degradation of the organic membranes(e.g.polyamide)by the strong oxidative radicals(e.g.OH)generated via the activation of H_(2)O_(2)by iron ions(Fe^(3+)),the short effective lifetime of membranes remains a challenge.Inorganic nano tin oxide(SnO_(2))has great potential for the removal of Fe^(3+)in strongly oxidative H_(2)O_(2)because of its ability to stabilize H2O_(2)and preferentially adsorb Fe^(3+).Herein,we have designed for the first time a flower-like robust SnO_(2)membrane on the ceramic support by in situ template-free one-step hydrothermal method.The three-dimensional loose pore structure in the membrane built by interlacing SnO_(2)nanosheets endows the SnO_(2)membrane with a high specific surface area and abundant adsorption sites(AOH).Based on the coordination complexation and electrostatic attraction between the SnO_(2)surface and Fe^(3+),the membrane shows a high Fe3+removal efficiency(83%)and permeability(24 L·m^(-2)·h^(-1)·MPa^(-1))in H_(2)O_(2).This study provides an innovative and simple approach to designing robust SnO_(2)membranes for highly efficient removal of Fe^(3+)in harsh environments,such as strong oxidation conditions.

Pilot Test of Preparing 2-Alkylanthraquinone Using Alkylation-Oxidation Technology

To expedite the development of industrial technology for producing 2-alkylanthraquinone,a novel pilot test of alkylation-oxidation technology was conducted.The process mainly included anthracene alkylation,separation of anthracene and 2-alkylanthracene,oxidation of 2-alkylanthracene,and product purification.Optimal alkylation conditions yielded a 91.1%conversion of anthracene and a 71.73%selectivity for 2-alkylanthracene.To address the separation problem of anthracene and 2-alkylanthracene,solvent-assisted distillation technology was developed,resulting in a 98.9%purity of 2-alkylanthracene and a 91.82%separation yield.When the molar ratio of H2O_(2) to 2-alkylanthracene was 7:1,a 98.96%conversion of 2-alkylanthracene and a 99.94%selectivity for 2-alkylanthraquinone were achieved.A novel composition of 2-alkylanthraquinone,including 2-tert-butylanthraquinone,2-tert-amylanthraquinone,and 2-hexylanthraquinone,was developed.This composition could be effectively separated and purified through a combination of crystallization and washing processes.The elemental composition of the product met the existing standards,and its hydrogenation performance closely matched that of commercially available 2-tert-amylanthraquinone products.