Free Radical Formation Research Articles

Photodegradation of poly(ether-b-amide) catalyzed by bismuth radiopaque additive

Bismuth compounds (e.g., bismuth subcarbonate and bismuth oxychloride) are often used as radiopaque additives in poly(ether-b-amide) (PEBA) for medical catheter applications to enhance the visibility of the catheter tips during fluoroscopy-guided minimally invasive surgeries. However, there is an increasing number of reports on bismuth-based photocatalysts in other fields; yet the impact of bismuth additives on the shelf life of PEBA has never been studied/reported. In this work, the stability of PEBA containing bismuth subcarbonate was tested against PEBA containing other radiopaque additives, barium sulfate and tungsten, in several real-life-relevant lighting conditions. It was found bismuth-containing PEBA degraded significantly faster than these counterpart materials under light exposure conditions including indoor fluorescent light, daylight-simulating xenon light and high-flux visible blue light. The extents of photodegradation of bismuth-containing PEBA were characterized by optical imaging, tensile test, FTIR analysis, Raman imaging and ESR radical analysis. The results showed material surface cracking, material hardening, surface oxidation and radical concentration increase over the course of light exposure. Various environmental factors were studied; it was found PEBA containing bismuth not only degraded under lights containing UV light but also degraded under high intensity visible blue light. Larger doses of light exposure and higher environmental temperatures led to more material degradation. Additional shelf aging studies on light-exposed samples were performed, which showed latent aging with continued degradation shortening the shelf life after the initial light exposure, due to the formation of persistent free radicals. Finally, several design and use considerations were discussed in the context of catheter material photodegradation.

ROS scavenging, DNA binding and NADPH oxidase inhibition potential of N’-Ferrocenylmethyl-N’- phenylpropionohydrazide using cyclic voltammetry and molecular docking

Overactivation of the NOX results in an excess production of ROS, which is linked to oxidative stress and deoxyribonucleic acid (DNA) damage. Free radical formation is a physiological event mainly coming from cellular respiration. Inflammatory diseases, cardiovascular diseases, and cancer are only some illnesses that this could trigger. Therefore, chemicals that can block NADPH oxidase (NOX) are essential in maintaining a healthy level of oxidative stress. However, interacting with DNA can alter its shape and slow replication, protecting cells from death. In this study, cyclic voltammetry (CV) techniques were employed to assess the scavenging activity of N’-Ferrocenylmethyl-N’- phenylpropionohydrazide (NFPP) towards the superoxide anion radical (O2.−). Additionally, the DNA binding modes and binding free energies of NFPP were investigated. To support the experimental results, molecular docking was performed with DNA (PDB ID: 5VY6) and the enzyme NOX1 (PDB ID: 7CFZ). The results were consistent between the two approaches, showing that the chemical investigated had an IC50 lower than that of ascorbic acid (AA) and a spontaneous form of binding with (O2.−) and DNA due to the negative sign of binding energies. Minor groove binding with two conventional hydrogen bonds was the type of interaction with the DNA. The binding energy between NFPP and NADPH exhibited a significant correlation with the experimental findings, indicating a strong affinity and a reduced inhibition concentration compared to ascorbic acid.

Crystal defect engineering to construct oxygen vacancies in MXene-derived TiO2 nanocomposites for boosting photocatalytic degradation of 2,4,6-trichlorophenol

Chlorophenolic pollutants pose serious threats to the aquatic ecosystem. Photocatalysis technology has broad prospects for decontamination. In this work, MXene-derived TiO2 nanocomposites with mixed-crystal characteristics and oxygen vacancies (OVs) (E–TiO2@rGO) were successfully synthesized by atmosphere modulation. Compared with commercial TiO2 and N2–TiO2@rGO (anatase phase), the rate constants of E–TiO2@rGO (0.06874 min−1) over 2,4,6-trichlorophenol (2,4,6-TCP) degradation increased 4 and 1.3 times, respectively. The enhanced photocatalytic performance was attributed to the co-existence of anatase and rutile phases. On the one hand, the mixed-crystal phase narrowed the band gap, broadening the light absorption range. On the other hand, it induced the generation of OVs, which has been demonstrated by DFT calculation. The presence of OVs improved the adsorption and activation of O2 and H2O molecules, beneficial for the formation of active free radicals. In addition, the incorporation of rGO promoted the separation of electron-hole pairs. The Gibbs free energy of 2,4,6-TCP degradation revealed that the OVs and mixed-crystal could reduce the energy barrier of the rate-determining step, thereby boosting the dichlorination efficiency of 2,4,6-TCP. The superoxide free radical (O2−) was determined as the dominant active species. Finally, a possible mechanism of 2,4,6-TCP degradation with E–TiO2@rGO was clarified clearly. The proposed mixed-crystal defect engineering represents a novel strategy in the design and synthesis of photocatalysts.

The influence of tritium behaviour on spent fuel pool concrete

This paper investigates the effects caused by Tritium released from spent nuclear fuel (SNF) stored into a spent nuclear pool made of (reinforced) concrete. The release of tritium from fuel elements to coolant during normal LWRs operation is of 1 % while during 6–20 years of wet storage is assessed to 13–45 %. Permanent Tritium concentration in coolant is assessed to n·109 Bq·dm−3.The water contamination first and the filtration of the concrete pool walls then pose important safety problems to face from both radiological and structural point of view: during Tritium filtration, radiation affects significantly the structural and mechanical properties of concrete due to the breaking of atomic bonds.Under the effect of radiation concrete microstructure modifies; collision determines atom dislocation and so a lattice defect. Ionized rays may cause the decay of free or bonded water leading to the formation of H2 and O2 and produce explosive mixture.The damage from “soft” β-decay of Tritium inside the concrete could be harder due to short track of the particle and the resulting “volume” effect. Neither this effect nor to what extent Tritium movement in/through concrete material would take place over long-term are yet completely studied.Due to Helium (He) formation, when Tritium decays, the restructuring of water molecules with generation of reactive free radicals occurs. We have assessed these effects: the irradiation and accompanying volume expansion, formation of free radicals and corresponded chemical corrosion are not considerably influencing on the structure and sustainability of concrete biological shield. The most significant effect is the radiation breaking of van der Waals bonds that within 10 years can lead to the destruction of about 2 % of concrete.Concrete shield does not provide a complete barrier against Tritium release into the environment. The main threat of Tritium diffusion to coolant in SNF storage pools is caused by filtration of tritiated water through the concrete walls that may provide significant health hazards for employees of the nuclear industry. Results show that β-decay of tritiated water adsorbed in 1 m3 of concrete may destroy about of 0.05 mol (11.4 g) of cement stone within 10 years, which is less than 0.001%. Moreover, with 3. With reference to the 5th power unit of the Zaporizhzhia NPP, the volume of Tritiated water released from the pool is 0.67 m3 annually. Resultsshow that the tritium waste management concept needs to be revised.

The relationship between oxidative degradation and ammonia emission of carbon capture amines based on their chemical structures

Abstract This work investigates the effect of chemical structural positioning of different functional groups in 29 amines covering primary, secondary and tertiary alkanolamines as well as multi-alkylamines and cyclic amines on both amine degradation and ammonia (NH3) emissions during post-combustion amine-based carbon dioxide capture. The results helped to elucidate possible relationships between degradation and emissions as related to the chemical structure of the amine. The results showed that longer alkyl chain lengths in multi-alkylamines caused a more drastic decrease in both degradation and NH3 emissions followed by secondary alkanolamines. The decrease in those activities for primary and tertiary alkanolamines as well as cyclic amines was low and more so for NH3 emissions. In contrast, the increase in hydroxyl groups in secondary alkanolamines caused a drastic increase in degradation and NH3 emissions. On the other hand, having more hydroxyl groups in sterically hindered primary and tertiary alkanolamines caused a more drastic decrease in degradation and a smaller decrease in NH3 emissions due to the steric hindrance within their structure. An increase in the number of amino groups in an amine caused an increase in both degradation and NH3 emission rates because these provided the reactive sites for the formation of free radicals. This effect was not as large in alkyl-cyclic amines as in multi-alkylamines due to the ability of the former to resist oxidative degradation. Furthermore, branched alkyl groups between amino and hydroxyl groups more drastically increased both the degradation and NH3 emission activities than branched alkyl groups located at the nitrogen atom.

Diabetic ketoacidosis and oxidative stress: pathophysiological mechanisms

Diabetes mellitus (DM) is a common endocrine disease with a large number of acute and chronic complications, among which diabetic ketoacidosis (DKA) is the most frequent and severe, especially in children and adolescents with type 1 DM. Oxidative stress (OS) is a pathological condition that develops due to an imbalance between free radicals formation and inefficiency of the antioxidant system. OS is a strong risk factor for the development of numerous diabetic complications. Recently OS has been considered as an important component of DKA, the pathophysiological mechanisms of which have not yet been fully elucidated. This paper describes hypotheses according to which OS not only triggers and exacerbates manifestations of DKA, but itself represents a severe consequence of DKA, leading to the progression of numerous micro- and macroscopic diabetic complications. The formation of glycation end products, activation of protein kinase C, polyol and hexosamine pathways are considered among the key pathophysiologic mechanisms of OS development in DKA. Achieving a better understanding of OS pathogenesis in DKA will optimize the diagnosis of OS and approaches to DKA correction through timely prescription of antioxidants.

Advancements in emerging MXene-integrated nanocomposite coatings: Unraveling defect-free microstructure for superior tribological, mechanical, and anti-aging features

This study explored the enhancement potential of MXene, a novel two-dimensional material, in epoxy-based nanocomposites; which comprehensively examined the influence of MXene on epoxy's viscosity, void formation, aging resistance, mechanical properties, and anti-wear properties. MXene nanofillers, labeled as 25C and 80C, fabricated via different acid-etching methods, were incorporated into epoxy resin at varying weight percentages (0.1–2.0 wt%). Observations revealed that for both varieties of MXene, inclusion of 1.0 wt% MXene led to the mitigation of void content, whereas the incorporation of 2.0 wt% MXene yielded maximal enhancements in both tensile strength and abrasion resistance. Additionally, the integration of 1.0 and 2.0 wt% MXene displayed superior aging resistance, with around 80 % reduction in free radical formation compared to the unmodified epoxy, while maintaining its excellent mechanical properties after QUV exposure. Therefore, both MXene types significantly enhanced the performance of epoxy composites, with the 80C-MXene displaying marginally superior enhancement due to its smaller particle size and higher purity, as identified by SEM and TEM images.

Vitamin E-enriched medium cross-linked polyethylene in total knee arthroplasty (VIKEP): clinical outcome, oxidation profile, and wear analysis in comparison to standard polyethylene—study protocol for a randomized controlled trial

BackgroundThe gliding surface of total knee endoprostheses is exposed to high loads due to patient weight and activity. These implant components are typically manufactured from ultra-high molecular weight polyethylene (UHMWPE). Crosslinking of UHMWPE by ionizing radiation results in higher wear resistance but induces the formation of free radicals which impair mechanical properties after contact with oxygen. Medium-crosslinked UHMWPE enriched with vitamin E (MXE) provides a balance between the parameters for a sustainable gliding surface, i.e., mechanical strength, wear resistance, particle size, and oxidation stability. Therefore, a gliding surface for knee endoprostheses made up from this material was developed, certified, and launched. The aim of this study is to compare this new gliding surface to the established predecessor in a non-inferiority design.MethodsThis multicenter, binational randomized controlled trial will enroll patients with knee osteoarthritis eligible for knee arthroplasty with the index device. Patients will be treated with a knee endoprosthesis with either MXE or a standard gliding surface. Patients will be blinded regarding their treatment. After implantation of the devices, patients will be followed up for 10 years. Besides clinical and patient-related outcomes, radiological data will be collected. In case of revision, the gliding surface will be analyzed biomechanically and regarding the oxidative profile.DiscussionThe comparison between MXE and the standard gliding surface in this study will provide clinical data to confirm preceding biomechanical results in vivo. It is assumed that material-related differences will be identified, i.e., that the new material will be less sensitive to wear and creep. This may become obvious in biomechanical analyses of retrieved implants from revised patients and in radiologic analyses.Trial registrationClinicalTrials.gov, NCT04618016. Registered 27 October 2020, https://clinicaltrials.gov/study/NCT04618016?term=vikep&checkSpell=false&rank=1.All items from the World Health Organization Trial Registration Data Set can be found in Additional file 1.

Analysis of Knowledge of Professional Dentist Students Regarding Dentistry Radiation In Pediatric

Backgroud: Radiation that often used in dentistry was the X-ray radiation. X-rays were used as a means of supporting the diagnosis because of its physical properties that can recorded the tissue image in its path on photographic film. Besides beneficial, X- rays can cause damage in the form of tissue damage due to its biological properties that can damaged deoxyribonucleic acid (DNA) and triggerred the formation of free radicals. The Professional (Koas) dental students in the University of Syiah Kuala (USK) of Oral and Dental Hospital (RSGM) Banda Aceh often used X-rays for diagnosis and treatment of teeth, so that they should had knowledge of radiation on children. Objective: of this study was to determined the level of knowledge of clinical dental students about radiation dentistry for children in the University of Syiah Kuala Oral and Dental Hospital Banda Aceh. Methods: of this research was a descriptive survey. The study involved 205 clinical dental students who met the inclusion criteria. Research subjects were asked to completed a questionnaire in the form of questions about radiation dentistry for children. Results: The study indicated the level of knowledge of clinical dental students about radiation dentistry for children amounted to 51.2% including moderate category, followed by 31,7% of good category and 17,1% poor category. Conclusion:The level of knowledge of clinical dental students about radiation dentistry for children mostly in the moderate category.

Order-Disorder Engineering of Carbon Nitride for Photocatalytic H2O2 Generation Coupled with Pollutant Removal.

Highly crystalline carbon nitride (CCN), benefiting from the reduced structural imperfections, enables improved electron-hole separation. Yet, the crystalline phase with insufficient inherent defects suffers from a poor performance toward the reaction intermediate adsorption with respect to the amorphous phase. Herein, a crystalline-amorphous carbon nitride (CACN) with an isotype structure was constructed via a two-step adjacent calcination strategy. Through specific oxygen etching and crystallization, the formation of a built-in electric field at the interface could drive charge transfer and separation, thus promoting photoredox reaction. As expected, the optimized CACN exhibited a H2O2 generation efficiency as high as 2.15 mM gcat-1 h-1, paired with a promoted pollutant degradation efficiency, which outperform its crystalline (CCN) and amorphous [amorphous carbon nitride (ACN)] counterparts. The detailed electron/hole transportation via a built-in electronic field and free radical formation based on the enhanced adsorption of oxygen were considered, and the synchronous reaction pathway was carried out. This work paves a novel pathway for the synthesis of carbon nitride with an isotype structure from the perspective of interfacial engineering.

The Comparative Study of Physical Exercise Towards Brain Natriuretic Peptide (BNP) and Malondialdehyde (MDA) as Oxidative Stress Markers in Rattus Novergicus Wistar Strain Rats

Background: Physical exercise has an effect on biological functions, namely a positive effect in terms of cell repair and a negative effect, namely inhibiting or damaging cells. Strenuous physical exercise can increase muscle injury and oxidative stress in individuals who are not conditioned or are not used to physical exercise. In addition, oxidative stress also plays a role in chronic fatigue syndrome. This occurs because the speed of energy demand exceeds the speed and ability of the oxygen transport system to supply oxygen to the mitochondria. The heart muscle is a muscle that has a major role in physical exercise. Oxidative stress plays an important role in the pathogenesis of myocardial infarction. Objectives: The purpose of this research is to determine the difference between aerobic and anaerobic exercise in the formation of free radicals. The formation of free radicals can be predicted by measuring levels of malondialdehyde (MDA) and Brain Natriuetic Peptide (BNP). Methods: The design used in this study was an experimental study in vivo with a pretest-posttest design with a comparison group. The subjects of this study were 28 male Wistar rats, Rattus novergicus, which were divided into 6 treatment groups and 1 comparison group. The data is taken by doing treadmill physical exercise with a speed of 20m / minute for aerobics and 35m / minute for anaerobics. Different tests of average MDA and BNP levels were used using independent t-tests, ANOVA, and post hoc. Result: The results showed a decrease in MDA and BNP levels in the aerobic treatment group and an increase in anaerobic compared to the comparison group. The analysis showed that there was a significant difference between the aerobic group for 1 day, 3 times a week, and 7 days, respectively, with p 0.05. Conclusion: It can be concluded that aerobic and anaerobic physical exercise performed 1 day, 3 times a week, and 7 consecutive days can increase the antioxidant defence system so that oxidative stress decreases, which is indicated by a decrease in MDA and BNP levels.

Effects of Gamma Radiation on Microbial Load and Chemical Constituents from Stem Barks of Luehea ochrophylla

Gamma radiation is an effective method for microbial decontamination of plant materials. However, this treatment can induce changes in the chemical structure of plant constituents. Stem barks of Luehea ochrophylla were exposed to different doses of gamma radiation to evaluate decontamination efficiency and changes in chemical composition of plant material including phenolic fraction. The major microbial contaminants of non-irradiated samples were isolated and identified as the fungal species Eurotium chevalieri L. Mangin and Lecythophora decumbens. The dose of 5.0 kGy was effective to achieve total decontamination of the stem barks of L. ochrophylla. The formation of free radicals was verified in the plant material using electron paramagnetic resonance spectroscopy, and was supposed to be related to the trans-aconitic acid, a plant constituent. It was the only secondary metabolite to have its concentration significantly altered with radiation in phenolic fraction, as observed by liquid chromatography with diode array detector coupled to mass spectroscopy (LC-DAD-MS). The trans-aconitic acid was isolated and exposed to gamma radiation in aqueous medium. Its concentration decreased after exposition to a dose of 3.0 kGy, corroborating the supposition of its degradation. Citric acid was the main radiolytic product formed by irradiation of trans-aconitic acid in the presence of water.

Single-domain magnetic particles with motion behavior under electromagnetic AC and DC fields are a fatal cargo in Metropolitan Mexico City pediatric and young adult early Alzheimer, Parkinson, frontotemporal lobar degeneration and amyotrophic lateral sclerosis and in ALS patients.

Metropolitan Mexico City (MMC) children and young adults exhibit overlapping Alzheimer and Parkinsons' diseases (AD, PD) and TAR DNA-binding protein 43 pathology with magnetic ultrafine particulate matter (UFPM) and industrial nanoparticles (NPs). We studied magnetophoresis, electron microscopy and energy-dispersive X-ray spectrometry in 203 brain samples from 14 children, 27 adults, and 27 ALS cases/controls. Saturation isothermal remanent magnetization (SIRM), capturing magnetically unstable FeNPs ~ 20nm, was higher in caudate, thalamus, hippocampus, putamen, and motor regions with subcortical vs. cortical higher SIRM in MMC ≤ 40y. Motion behavior was associated with magnetic exposures 25-100 mT and children exhibited IRM saturated curves at 50-300 mT associated to change in NPs position and/or orientation in situ. Targeted magnetic profiles moving under AC/AD magnetic fields could distinguish ALS vs. controls. Motor neuron magnetic NPs accumulation potentially interferes with action potentials, ion channels, nuclear pores and enhances the membrane insertion process when coated with lipopolysaccharides. TEM and EDX showed 7-20 nm NP Fe, Ti, Co, Ni, V, Hg, W, Al, Zn, Ag, Si, S, Br, Ce, La, and Pr in abnormal neural and vascular organelles. Brain accumulation of magnetic unstable particles start in childhood and cytotoxic, hyperthermia, free radical formation, and NPs motion associated to 30-50 μT (DC magnetic fields) are critical given ubiquitous electric and magnetic fields exposures could induce motion behavior and neural damage. Magnetic UFPM/NPs are a fatal brain cargo in children's brains, and a preventable AD, PD, FTLD, ALS environmental threat. Billions of people are at risk. We are clearly poisoning ourselves.

NÍVEIS TOTAIS DE OXIDANTE E ANTIOXIDANTE TOTAL EM PACIENTES COM CÁLCULOS NA VESÍCULA BILIAR OU COMPLICAÇÕES RELACIONADAS: SÃO IMPORTANTES NO TRATAMENTO?

ABSTRACT BACKGROUND: Many free radicals result in an inflammatory process due to complications caused by gallstones. These free radicals are inactivated by various reactions and participate in different reactions. Molecules are oxidants and antioxidants that take an active role in almost every event that takes place in the body. AIMS: To analyse the changes in total antioxidant level (TAL) and total oxidant level (TOL) in the follow-up of patients hospitalized for cholelithiasis or its complications, showing the active oxidative stress, and to test the usability of these parameters in the evaluation of treatment success. METHODS: Forty-five patients took part in the study. Blood samples were taken twice, previous to surgery and 6 hours after surgery. Tissue samples were also obtained from patients who were operated. Then, the samples were sent to a laboratory to measure the total oxidant and antioxidant status of patients. RESULTS: The median for the TAL_before (pre-operation or hospitalization in non-operational) variable was 2.40 (interquartile range — IQR=0.50), and the median for the TAL_after variable was 2.20 (IQR=0.33). The median of the tissue-derived TAL variable was 0.32 (IQR=0.13), and the median of the TOL variable was 0.43 (IQR=0.52). The median value of the TAL_before variable for men was 2.50 (IQR=0.50), while the median value for the TAL_before variable for women was 2.30 (IQR=0.50). TAL_before variable values did not show a statistically significant difference according to gender (Z=1.446; p=0.154, p>0.05). Similarly, the median values of TOL_before variable by gender were similar (Z=0.614; p=0.545, p>0.05). CONCLUSIONS: Cholelithiasis and its complications cause many inflammatory responses, ending with free radical formation. During follow-up, its level decreases due to consumption or success of the treatment.

Synthesis and characterization of novel uranyl clusters supported by bis(pyrazolyl) methane ligands: biomimetic catalytic oxidation, BSA protein interaction and cytotoxicity studies.

Two novel uranyl complexes were synthesized using bis-pyrazolyl methane ligands. The complexes were characterized by several spectroscopic techniques, including UV-Vis, IR, NMR, mass spectrometry, fluorescence, electrochemical, and thermogravimetric analysis. The solid-state structure of the complex C1 was determined with the help of single-crystal X-ray diffraction studies. The complexes C1 and C2 efficiently catalyse the oxidation of 3,5-di-tert-butyl catechol and 2-aminophenol in the atmospheric air, imitating the catalytic activity of the catechol oxidase and phenoxazinone synthase enzymes. The kinetic parameters and the catalytic efficiency (K cat/K M) of the reactions were calculated. Formation of organic free radicals in the catalytic reactions was confirmed by EPR spectroscopy. The interaction of these complexes with the protein, bovine serum albumin, was investigated by using UV-Vis and fluorescence spectral analysis. The cytotoxicity of the complexes against MDAMB-231 and A549 cell lines was investigated, and IC50 values were determined.

Reducing the impact of artificial blue light on the skin: A spectroscopic study

Abstract As people spend many hours looking at digital screens, the negative effects of artificial blue light are becoming more apparent. While most research has focused on its effects on eyes, less is known about the effects of blue light on the skin, where similar photoreceptors are located. Unlike the sunscreens against UVB and UVA radiation, there is no standard method for determining skin protection against blue light. The lipophilic complex Carotolino, a system combining carrot root extract, carrot seed oil, and β-carotene, was chosen as a model substance for this research. Spectrophotometric investigation demonstrated the ability of Carotolino to absorb radiation in the blue light region (400—500 nm). After a 60-minute LED@450 nm exposure, corresponding to the maximum wavelength of radiation from the displays of common smartphones, only small changes (1.4 %) in the optical spectra were observed. The spectra showed sufficient photostability of Carotolino and its stabilizing effect on the photolabile Ubiquinone. In the 415—455 nm wavelength range associated with oxidative stress, Carotolino (0.4 % wt.) reduced blue light by ∼97.0 %. EPR spin trapping showed that blue light with a maximum wavelength of 450 nm causes significant formation of reactive free radicals, which can be partially eliminated by the application of Carotolino. The results confirmed the suitability of both methods to evaluate the effectiveness of substances to reduce physical impact of incident light on the skin. Further methods are needed to investigate biological protection of skin against blue light by promising substances.

Adrenergic effect on women's blood neutrophil oxidative activity the first day after delivery.

Recent studies have described a significant role for neutrophils in reproductive processes and their participation in the preparation of the cervix for childbirth and the activation of labor, in the postpartum involution of the uterus, and in the occurrence of preeclampsia. This study aimed to assess the formation of free radicals by neutrophils in the blood of women on the first day after childbirth and to characterize the adrenergic effect on this process. Venous blood samples from 100 female volunteers aged 26-32 years who had 2 or 3 full-term deliveries were collected and analyzed. Various adrenergic compounds were considered (agonists alphaand betaadrenoreceptors, adrenoblockers). The intensity of the respiratory burst of neutrophils and the effect of adrenergic substances on them were assessed with latex-induced luminol-dependent chemiluminescence. Neutrophil activity depends on the stage of the woman's reproductive process: it decreases during pregnancy, reaches the lowest values during childbirth, and increases significantly in the first hours after childbirth. On the first day after childbirth, alpha-1-adrenergic receptors are highly active in neutrophils, through which NADP-H-oxidase is activated and activated oxygen species are formed. At the same time, alphaor beta-agonists inhibit the radical activity of cells. Latex-induced oxidative burst of female blood neutrophils correlates with the stage of the reproductive process. Stressful conditions in the postpartum period can suppress the ability of neutrophils to release reactive oxygen species, which increases the risk of postpartum infections.

Free Radical Lipid Peroxidation Induced by Reactive Halogen Species.

The review is devoted to the mechanisms of free radical lipid peroxidation (LPO) initiated by reactive halogen species (RHS) produced in mammals, including humans, by heme peroxidase enzymes, primarily myeloperoxidase (MPO). It has been shown that RHS can participate in LPO both in the initiation and branching steps of the LPO chain reactions. The initiation step of RHS-induced LPO mainly involves formation of free radicals in the reactions of RHS with nitrite and/or with amino groups of phosphatidylethanolamine or Lys. The branching step of the oxidative chain is the reaction of RHS with lipid hydroperoxides, in which peroxyl and alkoxyl radicals are formed. The role of RHS-induced LPO in the development of human inflammatory diseases (cardiovascular and neurodegenerative diseases, cancer, diabetes, rheumatoid arthritis) is discussed in detail.

Systemic allopurinol administration reduces malondialdehyde, interleukin 6, tumor necrosis factor α, and increases vascular endothelial growth factor in random flap Wistar rats exposed to nicotine.

Smoking poses a risk to flap viability, with nicotine being a major contributor to the formation of free radicals. Allopurinol, known for its antioxidant properties, has been shown to enhance tissue survival in ischemic conditions by reducing the production of reactive oxygen species (ROS). This study aims to assess the impact of allopurinol on the viability and success of skin flaps in Wistar rats exposed to nicotine. This study examined skin flap survival in nicotine-exposed rats treated with allopurinol. Twenty-eight rats were separated into two groups. During 1 month of nicotine exposure, the treatment group received systemic allopurinol 7 days before and 2 days after the flap procedure, while the control group received no allopurinol. Pro-angiogenic factors, proinflammatory factors, anti-inflammatory factors, and oxidative markers were assessed on the 7th day after the flap procedure using enzyme-linked immunosorbent assay method. Macroscopic flap viability was evaluated on the 7th day using Image J photos. As an oxidative marker, malondialdehyde levels were significantly lower in rats given allopurinol than in controls (P < 0.001). The levels of interleukin 6 and tumor necrosis factor α, as markers of inflammatory factors, were significantly lower in the group of rats given allopurinol compared to controls (P < 0.001). The level of angiogenesis in rats given allopurinol, measured by vascular endothelial growth factor levels, was also higher in the treatment group compared to controls (P < 0.001). Macroscopically, the percentage of distal flap necrosis in Wistar rats given allopurinol was lower and statistically significant compared to controls (P < 0.001). Xanthine oxidoreductase is part of a group of enzymes involved in reactions that produce ROS. Allopurinol, as an effective inhibitor of the xanthine oxidase enzyme, can reduce oxidative stress by decreasing the formation of ROS. This reduction in oxidative stress mitigates the risk of ischemic-reperfusion injury effects and significantly increases the viability of Wistar rat flaps exposed to nicotine.

The effect of S‐allyl L‐cysteine on retinal ischaemia: The role of MCP‐1 and PKM2

Aims/Purpose: Retinal ischaemia plays an important role in vision threatening retinal ischaemic disorders, such as central/branch RAO, nvAMD and normal tension glaucoma. The aim of this study was to determine the effects of S‐allyl L‐cysteine (SAC) and its underlying mechanism.Methods: Porcine RPE (pRPE) cells were extracted from adult pig eyes and maintained in DMEM containing 10% FBS, 100 U/mL penicillin and 100 mg/mL streptomycin in a humidified atmosphere of 95% air and 5% CO2 at 37°C. Cell viability was evaluated by via a haemocytometre under an optical microscope. H2O2 (500 μM) was added for 24 h to stimulate an oxidative stress and SAC or vehicle was added to some groups of the cultured pRPE cells 15 min before adding H2O2.Besides, high intraocular pressure (HIOP)‐induced retinal ischaemia was established by raising IOP to 120 mmHg for 60 min in a Wistar rat eye. This ischaemic insult is followed by 7 days of reperfusion. Whether and how ‘SAC’ is able to prevent retinal ischaemic injury were assessed by electrophysiology, fluorogold‐labeling and ELISA/western blot.Results: H2O2 (500 μM) stimulated free radical formation in cultured pRPE cells and significantly reduced the cell viability. This harmful effect was dose‐dependently (25/50 μM) and significantly (100 μM) ameliorated by pretreatment with SAC. Moreover, post‐administration of mega‐dose SAC (I/R + SAC 9 μg/kg/day ≈ 0.18 mg/0.2 Kg rat) counteracted the ischaemia‐induced decrease in the ERG b‐wave and reduction in the RGC cell number in the rat retina. This study supports an antioxidative role for SAC. Through the ELISA/western blot, SAC (100 μM) appears to protect against H2O2‐induced oxidative stress via the downregulation of ischaemia‐related factor PKM2 and inflammatory biomarker MCP‐1.Conclusions: SAC might protect against retinal ischaemia by antioxidation, anti‐ischaemia and anti‐inflammation (downregulating PKM2 and MCP‐1).