In vitro pro- and antioxidant properties of estrogens

The pro- and antioxidant properties of estrogens are subject of debate. The apparent discrepancy is largely caused by the chemical heterogeneity in the estrogen family and by their concentration and the environment in which they are found. To gain some insight into this debate, we determined whether estradiol (E(2)), estrone (E(1)), the 2-, 4- and 16alpha-hydroxyestrogens and also the 2- and 4-methoxyestrogens are: (1) good electron-donors; (2) capable of O(2) consumption and DNA strand break induction; (3) capable of inhibiting lipid peroxidation in vitro. E(2), E(1) and 16alpha-hydroxyestrone (16alpha-OHE(1)) were not pro-oxidants and were rather weak antioxidants, while the 2- and 4-hydroxyestrogens demonstrated both properties inducing DNA strand breaks damage as well as inhibiting lipid peroxidation. The 4-hydroxyestrogens consumed O(2) and induced DNA strand breaks to a level approximately 2.5-fold higher than the 2-hydroxyestrogens, but these hydroxyestrogens exhibited similar antioxidant capacity, as measured by inhibition of lipid peroxidation. The 4-methoxyestrogens cannot induce oxidative damage to DNA but can inhibit lipid peroxidation, although being less potent than the 2-methoxyestrogens and the 2- and 4-hydroxyestrogens. The 2-methoxyestrogens were both potent electron donors and inhibitors of lipid peroxidation. Although 2-methoxyestrogens cannot generate superoxide in vitro, they may also be considered pro-oxidants in vivo.     

Hypoxic preconditioning modifies activity of pro- and antioxidant systems in the rat hippocampus

The effects of repetitive mild hypobaric hypoxic preconditioning on pro- and antioxidant systems in rat hippocampus have been studied. It was found that three-trial preconditioning by mild hypobaric hypoxia (360 mm Hg, 2 h) induced moderate oxidative stress immediately after the last preconditioning trial. In addition, it down regulated the levels of protein antioxidants (Trx-1, Trx-2, Cu,Zn-SOD) and also decreased several lipid peroxidation products 24 h after the preconditioning.     

Effect of melatonin and radiation on pro- and antioxidant state of the liver and blood of rats

The pro- and antioxidant state of the liver and blood of rats under the effect of melatonin and radiation in the total dose of 20 Gy has been studied. Irradiation by the broad fields intensifies the processes of lipoperoxidation and oxidative modification of proteins with simultaneous inhibition of the antioxidant protection. Melatonin administered against a background of radiation caused a distinctly expressed antioxidant effect.     

The activity of pro- and antioxidant systems in the liver of freshwater fishes during different seasons

The content of lipid peroxidation products--diene conjugates, lipid hydroperoxides, thiobarbituric acid reactive substances (TBARS), vitamins A, E and carotenoids and the activity of antioxidant enzymes--superoxide dismutase, glutathione peroxidase and catalase in the liver of freshwater fishes of different species (silver carp, grass carp and common carp) in different seasons have been studied. It was established the activity of antioxidant defence system in the liver of fish depends significantly on the season and fish species. In particular, the content of lipid peroxidation products in the liver of freshwater fishes at the beginning of winter and spring was significantly higher compared to their content at the beginning of summer and autumn. The superoxide dismutase and glutathione peroxidase activities in the liver of these fish species at the beginning of winter and spring were significantly lower than at the beginning of summer and autumn while the seasonal changes of catalase activity in the liver of fish are expressed insignificantly. The content of vitamins E, A1, A2 and carotenoids in the liver of fishes of different species at the beginning of winter and spring was significantly lower than at the beginning of summer and autumn. The content of lipid peroxidation products and vitamins E, A1 and A2 in the liver of common carp is significantly lower than in the liver of silver carp and grass carp and species differences in antioxidant enzymes activity are insignificant.     

The influence of electromagnetic radiation of extremely high frequencies on the pro- and antioxidant status of blood in experiments

The influence of electromagnetic radiation of extremely high frequencies in the noise mode on the level of the activity of proand antioxidant systems in a model of skin-flap ischemia was studied in vivo. Rats of the Wistar line were used in this work. The cutaneous reflex projection field of the animals was exposed once a day for 7 days in the post-operative period to electromagnetic radiation of an extremely high frequency in the range from 53.57 to 78.33 GHz with a dose of 1.2 mJ in the noise mode. The dynamics of proand antioxidant protection were compared to those of intact animals that were not irradiated. Using data on induced biochemiluminescence and estimation of malondialdehyde activity it was shown that irradiation in a course mode contributed to a decrease in the intensity of lipid peroxidation. In parallel we observed an increase in the total antioxidant reserves of blood and the activity of bioradical protection enzymes. Our findings suggest that electromagnetic radiation at extremely high frequencies in a noise mode has a regulatory impact on the state of proand antioxidant systems of the body; this can be used for the correction of postoperative ischemic disorders and the restoration of disturbed homeostasis.     

Effect of jasmonic acid on the pro-/antioxidant system of wheat coleoptiles as related to hyperthermia tolerance

The effects of treatment with jasmonic acid (JA) of wheat (Triticum aestivum L, cv. Elegia) coleoptiles on the generation of superoxide anion-radical (O ₂ ^·? ), the activity of extracellular peroxidase, enzymatic and non-enzymatic components of the antioxidant system were studied. During the first hour after the start of coleoptile treatment with 1 μM JA, the generation of O ₂ ^·? was enhanced and the extracellular peroxidase was activated. During following 23 h, these effects were gradually reduced. JA-enhanced O ₂ ^·? generation was partially suppressed by coleoptile treatment with the inhibitor of peroxidase salicylhydroxamic acid, the inhibitor of NADPH-oxidase imidazol, and also the calcium chelator EGTA. Under the influence of JA treatment, antioxidant enzymes (superoxide dismutase, catalase, ascorbate peroxidase, and soluble guaiacol peroxidase) in wheat coleoptiles were activated. Treatment with JA improved coleoptile tolerance to damaging heating (10 min at 43°C); it favored the maintenance of the pools of enzymatic and non-enzymatic antioxidants. The inhibitors of NADPH-oxidase and peroxidase, and also calcium chelator reduced a positive JA influence on coleoptile thermotolerance. The role of changes in the pro-/antioxidant balance in plant tissues for the realization of stress-defensive JA effects is discussed.     

Evaluation of the antioxidant activity of flavonoids by "ferric reducing antioxidant power" assay and cyclic voltammetry

Flavonoids, naturally occurring phenolic compounds, have recently been studied extensively for their antioxidant properties. The structure-antioxidant activity relationships (SAR) of flavonoids have been evaluated against different free radicals, but "ferric reducing antioxidant power" (FRAP) assay, which determines directly the reducing capacity of a compound, has not been used for this purpose. In this study, the antioxidant activities of 18 structurally different flavonoids were evaluated by FRAP assay modified to be used in 96-well microplates. Furthermore, their oxidation potentials were also measured, which were in the range of +0.3 V (myricetin) to +1.2 V (5-hydroxy flavone) and were in good agreement with FRAP assay results. Quercetin, fisetin and myricetin had the lowest oxidation potentials and appeared the most active compounds in FRAP assay and were 3.02, 2.52 and 2.28 times more active than Trolox, respectively. Indications were found that the o-dihydroxy structure in the B ring and the 3-hydroxy group and 2,3-double bond in the C ring give the highest contribution to the antioxidant activity.     

The effect of 1-methylcyclopropene on the components of pro- and antioxidant systems of wheat and the development of defense reactions in fungal pathogenesis

The effect of 1-methylcyclopropene (1-MCP), which inhibits the reception of ethylene, on the following has been studied: hydrogen peroxide generation, oxalate oxidase activity, peroxidase activity, catalase activity, and lignin accumulation in infected leaves of soft spring wheat (Triticum aestivum L.) cultivars that differ in their resistance to the leaf blotch disease, caused by the hemibiotrophic fungus Septoria nodorum Berk. A decrease in the development of leaf blotch in wheat leaves under the influence of 1-MCP was, on one hand, followed by an inhibition of catalase activity; on the other hand, it was accompanied by an increase in oxalate oxidase and peroxidase activity, as well as an accumulation of H₂O₂ in tissues and lignin in the infected zone. The role of the ethylene reception system in the defense response of plants to infection with a hemibiotrophic pathogen, that causes leaf blotch disease, is discussed.     

A review of fish-derived antioxidant and antimicrobial peptides: their production, assessment, and applications

Fishes are rich sources of structurally diverse bioactive compounds. In recent years, much attention has been paid to the existence of peptides with biological activities and proteins derived from foods that might have beneficial effects for humans. Antioxidant and antimicrobial peptides isolated from fish sources may be used as functional ingredients in food formulations to promote consumer health and improve the shelf life of food products. This paper presents an overview of the antioxidant and antimicrobial peptides derived from various fishes. In addition, we discuss the extraction of fish proteins, enzymatic production, and the techniques used to isolate and characterize these compounds. Furthermore, we review the methods used to assay the bioactivities and their applications in food and nutraceuticals.     

Understanding the pro- and anti-inflammatory properties of IL-27

The recent identification of IL-27 (IL-27p28/EBV-induced gene 3) and IL-27R (WSX-1/gp130) has provided new insights for the biology of IL-6/IL-12 family cytokines. Initial studies indicated that IL-27 can directly regulate T cell functions and suggested an important role for it in promoting Th1 type responses. However, subsequent studies have revealed that IL-27R signaling influences a variety of immune cell types and can inhibit either Th1 or Th2 type responses. Though elucidation of the Jak/STAT signaling pathways activated by IL-27R ligation has unveiled some of the molecular mechanisms used by IL-27 to promote inflammation, little is known about the anti-inflammatory activities of this cytokine. Thus, the aim of this review is to discuss the pleotropic nature of the IL-27/IL-27R interaction and attempt to reconcile the pro- and anti-inflammatory properties of this immunomodulator.     

CheapStat: an open-source, "do-it-yourself" potentiostat for analytical and educational applications

Although potentiostats are the foundation of modern electrochemical research, they have seen relatively little application in resource poor settings, such as undergraduate laboratory courses and the developing world. One reason for the low penetration of potentiostats is their cost, as even the least expensive commercially available laboratory potentiostats sell for more than one thousand dollars. An inexpensive electrochemical workstation could thus prove useful in educational labs, and increase access to electrochemistry-based analytical techniques for food, drug and environmental monitoring. With these motivations in mind, we describe here the CheapStat, an inexpensive (<$80), open-source (software and hardware), hand-held potentiostat that can be constructed by anyone who is proficient at assembling circuits. This device supports a number of potential waveforms necessary to perform cyclic, square wave, linear sweep and anodic stripping voltammetry. As we demonstrate, it is suitable for a wide range of applications ranging from food- and drug-quality testing to environmental monitoring, rapid DNA detection, and educational exercises. The device's schematics, parts lists, circuit board layout files, sample experiments, and detailed assembly instructions are available in the supporting information and are released under an open hardware license.     

Effect of the substances "Ammivit" and "cerloplasmin" on lipid peroxidation products level and of antioxidant system indicators under irradiation

It has been shown, that the total X-ray irradiation in the dozes of 0.5 and 1 Gy influences on the content of lipid peroxidation products and enzymatic activity of antioxidant system in rat spleen and thymus cells. The influence of preparations "AMMIVIT" and "Ceruloplasmin" on these processes is investigated also. So, the animals feeding by the vitamin concentrate "AMMIVIT" have lead to increase of MDA level (a final product of lipid peroxidation) and the overactivity of some antioxidant enzymes in rat spleen and thymus cells. Injection of the preparation "Ceruloplasmin" to experimental animals up 1 hour before the irradiation has normalized LPO intensity and activity of AO enzymes.     

Relaxant effects of sodium nitroprusside and NONOates in goat middle cerebral artery: delayed impairment by global ischemia-reperfusion.

Global cerebral ischemia and subsequent reperfusion induce early impairment of the vasodilator responses to hypercapnia and vasoactive substances. Nitric oxide (NO) is involved in the regulation of cerebral blood flow (CBF) in both health and disease. The present study was designed to assess possible changes in the cerebrovascular reactivity to NO donors induced by cerebral ischemia-reperfusion in goats. Female goats (n = 9) were subjected to 20 min global cerebral ischemia under halothane/N2O anesthesia. Sixteen additional goats were sham-operated as a control group. One week later the effects of ischemia-reperfusion on relaxations to NO donors sodium nitroprusside (SNP), diethylamine/NO (DEA/NO), diethylenetriamine/NO (DETA/NO), and spermine/NO (SPER/NO) were studied in rings of middle cerebral artery (MCA) isolated in an organ bath for isometric tension recording. SNP, DEA/NO, DETA/NO, and SPER/NO induced concentration-dependent relaxations of MCA precontracted with KCl (DEA/NO > SPER/NO > SNP > DETA/NO) or with endothelin-1 (DEA/NO > SNP > SPER/NO > DETA/NO). Relaxations were always higher in endothelin-1-precontracted arteries. One week after cerebral ischemia concentration-response curves to SNP and DEA/NO were displaced to the right, indicating a reduction in relaxant potency of NO donors. The classical nitrovasodilator SNP and NONOates induce relaxation of isolated goat MCA which is partially inhibited by arterial depolarization. Global cerebral ischemia followed by reperfusion induces delayed impairment of the relaxant effects of NO on cerebrovascular smooth muscle, which results in reduced vasodilatory potency of NO donors in large cerebral arteries.     

Hematopoietic stem cells in research and clinical applications: The "CD34 issue"

In this paper, experimental findings concerning the kinetics of hematopoietic reconstitution are compared to corresponding clinical data. Although not clearly apparent, the transplantation practice seems to confirm the basic proposals of experimental hematology concerning hematopoietic reconstitution resulting from successive waves of repopulation stemming from different subpopulations of progenitor and stem cells. One of the "first rate" parameters in clinical transplantations in hematology; i.e. the CD34+ positive cell dose, has been discussed with respect to the functional heterogeneity and variability of cell populations endowed by expression of CD34. This parameter is useful only if the relative proportion of stem and progenitor cells in the CD34+ cell population is more or less maintained in a series of patients or donors. This proportion could vary with respect to the source, pathology, treatment, processing procedure, the graft ex vivo treatment and so on. Therefore, a universal dose of CD34+ cells cannot be defined. In addition, to avoid further confusion, the CD34+ cells should not be named "stem cells" or "progenitor cells" since these denominations only concern functionally characterized cell entities.     

Disorders of equilibrium between pro- and antioxidant metalloprotein action in blood of albino rats after gangliosympathectomy and its combination with acute acoustic stress]

Unilateral ganglionsympathetectomy-removal of right upper cervical sympathetic ganglia and its combination with acute acoustic stress results in intensification of process of free radical oxidation of lipids and balance disturbance between components of antioxidative and pro-oxidative system of blood. Changes of composition and activity Cu, Zn-superoxide dismutase, catalase activity and contents of catalase, ceruloplasmin, transferrin and metalloproteins pro-oxidative action such as (cytochromes b558(I), b558(II), b558(III), b558(IV)) as well as O2-producing lipoprotein suprol and cytochromes b5 are evidence of compensating-adoptive function disturbances with according changes in blood, relatively to adaptive-trophic function of sympathetic system, its regulative role, in system of tissue metabolic conversion, which is directed, in particular, on compensation of anti-radical protection of cells.