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[en] Highlights: • Cell-free hemoglobin (CFH) increases endothelial barrier permeability. • Endothelial ascorbate is depleted following exposure to CFH. • Treatment of endothelial cells with ascorbate attenuates CFH mediated permeability. Increased endothelial permeability is central to shock and organ dysfunction in sepsis but therapeutics targeted to known mediators of increased endothelial permeability have been unsuccessful in patient studies. We previously reported that cell-free hemoglobin (CFH) is elevated in the majority of patients with sepsis and is associated with organ dysfunction, poor clinical outcomes and elevated markers of oxidant injury. Others have shown that Vitamin C (ascorbate) may have endothelial protective effects in sepsis. In this study, we tested the hypothesis that high levels of CFH, as seen in the circulation of patients with sepsis, disrupt endothelial barrier integrity.
[en] Complete text of publication follows. Ascorbic acid, AsA (vitamin c), has been widely studied as an antioxidant or as an initiator of some technological processes, for example polymerization or nanoparticles formation. AsA can be easily oxidized to ascorbyl radical, in the first stage, and to dehydroascorbic acid, DHA, in the second stage. It has been found that several different ascorbyl radicals are formed during AsA oxidation but the main radical exists as the anion with the unpaired electron delocalized on a highly conjugated tricarbonyl system. Absorption spectrum of ascorbyl radical shows two bands with maxima at 300 and 360 nm, however only that at 360 nm is proportional to the dose and thus this wavelength was chosen for observations. We studied the oxidation of AsA by the following oxidizing radicals generated by the pulse radiolysis method ·OH, (SCN)2-·, Cl2-·, N3· and NO2·. The observed dependence of the yield and the formation rate of the AsA radical on the reduction potential of the oxidizing radical is discussed. The results obtained in water are compared with those obtained with AsA enclosed in the water pools of reverse micelles formed by AOT in n-heptane or by Igepal CO-520 in c-hexane. Somewhat surprising observation of different ascorbyl radical in pulse irradiated reverse micelles containing DHA is also commented.
[en] Eight compounds were identified in ethanol extracts prepared from the branches of C. turczaninowii. The compounds, besides 5 and 6, were isolated for the first time from this woody plant. Pyracrenic acid (4) and quercitrin (8) showed potent DPPH free radical scavenging activities with SC50 values of 55.2 and 62.4 μM, respectively, where ascorbic acid (SC50 43.5 μM) was used as a positive control. Compounds 4, 5, 6 and 8 showed strong activities in ABTS+ radical scavenging assay, with SC50 values of 34.1, 42.1, 45.8 and 29.6 μM, respectively. These activities are comparable in potency to ascorbic acid (SC50 31.6 μM). Based on these results, C. turczaninowii extracts are expected to be useful antioxidative agents, potentially applicable in food or cosmetic industries, based on the results of further studies. Korean hornbeam Carpinus turczaninowii is a deciduous woody plant belonging to the family Betulaceae. This flora is endemic to Korea, and can reach a height of 15 m. In the autumn, the fallen leaves of C. turczaninowii display a beautiful orange-red color and the tree is commonly used for bonsai in Korea. The wood is very hard, dense and fine textured, and has been used for making agricultural tools and furniture. Previous chemical investigation on this plant indicated only the existence of flavonoids such as naringenin and quercetin glycosides from the leaves. We have recently reported the isolation diarylheptanoids possessing anti-inflammatory activities from the ethanol extract of C. turczaninowii
[en] During kidney development, the balance between self-renewal and differentiation of metanephric mesenchyme (MM) cells, mainly regulated by Sine oculis-related homeobox 2 (Six2), is critical for forming mature kidney. L-gulono-γ-lactone oxidase (Gulo), a crucial enzyme for vitamin C synthesis, reveals a different expression at various stages during kidney development, but its function in the early renal development remains unknown. In this work, we aim to study the role of Gulo in MM cells at two differentiation stages. We found that Gulo expression in undifferentiated MM (mK3) cells was lower than in differentiated MM (mK4) cells. Over-expression of Gulo can promote mesenchymal-to-epithelial transformation (MET) and apoptosis and inhibit the proliferation in mK3 cells. Knock-down of Gulo in mK4 cells made its epithelial character cells unstabilized, facilitated the proliferation and restrained the apoptosis. Furthermore, we found that Six2 was negatively regulated by Gulo, and over-expression or knock-down of Six2 was able to rescue partially the MET, proliferation and apoptosis of MM cells caused by Gulo. In conclusion, these findings reveal that Gulo promotes the MET and apoptosis, and inhibits proliferation in MM cells by down-regulating Six2.
[en] A simple and rapid spectrophotometric method for the determination of ascorbic acid is proposed. Ascorbic acid reduces iron (III) to iron (II) which forms a red colored complex with dimethylglyoxime in the presence of pyridine. The absorbance of the resulting solution is measured at 514 nm and a linear relationship between absorbance and concentration of ascorbic acid is observed up to 14 μg ml-1. Studies on the interference of substances usually associated with ascorbic acid have been carried out and the applicability of the method has been tested by analysing pharmaceutical preparations of vitamin C
[it]Si propone un rapido e semplice metodo spettrofotometrico per la determinazione dell'acido ascorbico. L'acido ascorbico riduce il ferro(III) a ferro(II) che forma con la dimetilgliossima, in presenza di piridina, un complesso colorato in rosso. L'assorbanza della soluzione risultante e' misurata a 514 nm e si ottiene una relazione lineare tra assorbanza e concentrazione dell'acido ascorbico fino a 14 μg ml-1. Si sono condotti studi sugli interferenti usualmente associati all'acido ascorbico ed e' stata valutata l'applicabilita' del metodo all'analisi di preparati farmaceutici di vitamina C
[en] Growth of multivitamin tablet production increases curiosity among the researchers whether ascorbic acid (AA) content is in accordance with the standards or not. The differential pulse anodic stripping voltammetry (DPASV) technique using bare glassy carbon electrode and phosphate buffer at pH 4.2 has been proposed to analyse the ascorbic acid content. The experimental voltammetric parameters were optimized to obtain a maximum response with analytical validation of the technique. The optimum instrumental conditions for electroanalytical determination of AA by the proposed DPASV technique were initial potential = 0 V, final potential = 0.7 V, accumulation time = 60 s, scan rate = 0.125 V/s, accumulation potential = 0 V and pulse amplitude = 0.150 V. The curve was linear from 5 mg L-1 to 300 mg L-1 (R2 = 0.9999) with detection limit of 0.25 mg L-1. The precisions in terms of relative standard deviation (RSD) were 1.3 %, 0.5 % and 0.06 %. The recoveries for AA content in the two multivitamin tablets were 98 % and 102 %, respectively. It can be concluded that the proposed technique is precise, accurate, rugged, low cost, fast and has the potential to be an alternative method for routine analysis of AA in other pharmaceutical products in future. (author)
[en] The role of ascorbate as an antioxidant in the prevention and cure of disease that result from free radicals has been of considerable interest and controversy lately. As an antioxidant, we can expect it to protect against radiation damage caused by free radicals that are produced when radiation, especially sparsely ionizing radiation, interacts with living tissues. The plasma and whole blood concentration of ascorbate was analyzed before and just after the radiation therapy for the purpose of estimating the consumption amount of ascorbate during radiotherapy. Whole blood ascorbate was decreased from 1.82 mg/dl to 1.58 mg/dl, plasma ascorbate was decreased from 1.13 mg/dl to 1.08 mg/dl, and urine ascorbate was decreased from 9.33 mg/dl to 6.96 mg/dl after radiotherapy. Although the difference was not significant statistically, further human study should be followed to define the role of ascorbate as a radioprotector
[en] Full text:Pollution of atmosphere air and lands is happening with transportation to be felt. Atomic energy enterprises throws up to the air radionuclide of heavy metals, which is more dangerous such as- 551Cr, 554Mn, 555Fe, 559Fe, 558Co, 660Co, 665Zn, 990V, 991V, 995Zn, 999Mo, 103Ru, 106Ru. These heavy metals don't create so threat according to their chemical structure, as their radioactivity. Air, water, land does not lose the low-activity, will be felt for years in the soil remained at the level of radioactive background by increasing the level of radiation is also increased. Life activity of plants undergone to the influence of the harmful geese in the atmosphere air is violated. Even small amounts of radiation and toxic ingredients influence to the plants negative. Thus, plants carry out the function of the indicator. For more information about the extent of human impact on plants recently test-systems are used in the search. As a result of analyzes of physiological active compounds that are studied, for example, pigments entozoan stress in plants are collected as an answer to the condition. Ascorbic acid takes part in cell immunities and plants to increase the sustainability of unfavorable conditions.