Synergistic effects of binary oil mixtures on the solubility of sunscreen UV absorbers.

Sunscreens for the photoprotection of human skin often are prepared as emulsions, containing organic UV-absorber molecules dissolved in the oil phase. The solubility of such oil-soluble UV-absorbers can be a limiting factor when aiming for high protection against UV-radiation. Possible synergistic effects of combinations of oil components toward UV-absorber solubility are therefore of great interest. Since a multitude of different combinations of oil components are possible, it would be desirable to predict synergistic effects by computational methods. As a model system, the solubility of a hydroxyphenyl triazine type UV-absorber was studied in several binary oil mixtures, experimentally and also by using a computational procedure based on density functional theory (DFT) and the continuum solvation model COSMO-RS. We have found good agreement of experimental and computational results. Computational methods may thus be employed to predict synergistic behaviour of solubility for systems containing two or more solvents.

Hippocampal lipidome and transcriptome profile alterations triggered by acute exposure of mice to GSM 1800 MHz mobile phone radiation: An exploratory study.

BACKGROUND: The widespread use of wireless devices during the last decades is raising concerns about adverse health effects of the radiofrequency electromagnetic radiation (RF-EMR) emitted from these devices. Recent research is focusing on unraveling the underlying mechanisms of RF-EMR and potential cellular targets. The "omics" high-throughput approaches are powerful tools to investigate the global effects of RF-EMR on cellular physiology. METHODS: In this work, C57BL/6 adult male mice were whole-body exposed (nExp  = 8) for 2 hr to GSM 1800 MHz mobile phone radiation at an average electric field intensity range of 4.3-17.5 V/m or sham-exposed (nSE  = 8), and the RF-EMR effects on the hippocampal lipidome and transcriptome profiles were assessed 6 hr later. RESULTS: The data analysis of the phospholipid fatty acid residues revealed that the levels of four fatty acids [16:0, 16:1 (6c + 7c), 18:1 9c, eicosapentaenoic acid omega-3 (EPA, 20:5 ω3)] and the two fatty acid sums of saturated and monounsaturated fatty acids (SFA and MUFA) were significantly altered (p < 0.05) in the exposed group. The observed changes indicate a membrane remodeling response of the tissue phospholipids after nonionizing radiation exposure, reducing SFA and EPA, while increasing MUFA residues. The microarray data analysis demonstrated that the expression of 178 genes changed significantly (p < 0.05) between the two groups, revealing an impact on genes involved in critical biological processes, such as cell cycle, DNA replication and repair, cell death, cell signaling, nervous system development and function, immune system response, lipid metabolism, and carcinogenesis. CONCLUSIONS: This study provides preliminary evidence that mobile phone radiation induces hippocampal lipidome and transcriptome changes that may explain the brain proteome changes and memory deficits previously shown by our group.

Ultrasound-assisted biodiesel production from Camelina sativa oil.

The main drawbacks of biodiesel production are high reaction temperatures, stirring and time. These could be alleviated by aiding transesterification with alternative energy sources, i.e. ultrasound (US). In this study, biodiesel was obtained from Camelina sativa oil, aided with an ultrasonic probe (20kHz, 70% duty cycle, 50% amplitude). Design of experiments included the combination of sonication and agitation cycles, w/wo heating (50°C). To gain knowledge about the implications of the proposed methodology, conventional transesterification was optimized, resulting in higher needs on catalyst concentration and reaction time, compared to the proposed reaction. Although FAME content met EN 14103 standard, FAME yields were lower than those provided by US-assisted transesterification. Energy consumption measurements showed that ultrasound assisted transesterification required lower energy, temperature, catalyst and reaction time.

Modifying effects of low-intensity extremely high-frequency electromagnetic radiation on content and composition of fatty acids in thymus of mice exposed to X-rays.

PURPOSE: The effects of extremely high-frequency electromagnetic radiation (EHF EMR) on thymus weight and its fatty acids (FA) content and FA composition in X-irradiated mice were studied to test the involvement of FA in possible protective effects of EHF EMR against ionizing radiation. MATERIALS AND METHODS: Mice were exposed to low-intensity pulse-modulated EHF EMR (42.2 GHz, 0.1 mW/cm(2), 20 min exposure, 1 Hz modulation) and/or X-rays at a dose of 4 Gy with different sequences of the treatments. In 4-5 hours, 10, 30, and 40 days after the last exposure, the thymuses were weighed; total FA content and FA composition of the thymuses were determined on days 1, 10, and 30 using a gas chromatography. RESULTS: It was shown that after X-irradiation of mice the total FA content per mg of thymic tissue was significantly increased in 4-5 h and decreased in 10 and 30 days after the treatment. On days 30 and 40 after X-irradiation, the thymus weight remained significantly reduced. The first and tenth days after X-rays injury independently of the presence and sequence of EHF EMR exposure were characterized by an increased content of polyunsaturated FA (PUFA) and a decreased content of monounsaturated FA (MUFA) with unchanged content of saturated FA (SFA). Exposure of mice to EHF EMR before or after X-irradiation prevented changes in the total FA content in thymic tissue, returned the summary content of PUFA and MUFA to the control level and decreased the summary content of SFA on the 30th day after the treatments, and promoted the restoration of the thymus weight of X-irradiated mice to the 40th day of the observations. CONCLUSIONS: Changes in the content and composition of PUFA in the early period after treatments as well as at the restoration of the thymus weight under the combined action of EHF EMR and X-rays indicate to an active participation of FA in the acceleration of post-radiation recovery of the thymus by EHF EMR exposure.

Fatty acids and vitamins generate singlet oxygen under UVB irradiation.

UVB radiation is already known as initiator and promoter of carcinogenesis in skin. UVB is well absorbed in proteins and DNA leading to products such as cyclobutane pyrimidine dimers. In contrast, UVA radiation generates reactive oxygen species such as singlet oxygen, which can initiate a variety of cellular damages and cellular signalling. It was the goal to investigate whether and to which extent UVB radiation is additionally able to cause oxidative damages via singlet oxygen. Potential endogenous photosensitizers such as vitamin B molecules or unsaturated fatty acids were irradiated in solution using monochromatic UVB radiation at 308 nm. Singlet oxygen was directly detected and quantified by its luminescence at 1270 nm. All investigated endogenous photosensitizers showed clear singlet oxygen signals with a quantum yield ranging from 5 to 40%. UVB radiation altered the photosensitizer molecules during irradiation yielding a change of absorption in the entire ultraviolet spectrum (280-400 nm). UVB irradiation of endogenous photosensitizers produced singlet oxygen that in turn changes the absorption of those molecules. Being an important prerequisite, the changed absorption may either reduce or increase singlet oxygen production. An increase in singlet oxygen generation may initiate a vicious cycle that has the potential to amplify UVB- or UVA-mediated effects in skin cells.

Rapid detection of radiation-induced hydrocarbons in cooked ham.

Solid phase microextraction (SPME) coupled with either gas chromatography-ionization flame detector (CG-FID) or multidimensional gas chromatography-mass spectrometry (MDGC-MS) was evaluated for its ability to detect volatile hydrocarbons produced during the irradiation of cooked ham. The chromatogram of an irradiated sample obtained using GC-FID showed a complex pattern of peaks, with several co-eluting peaks superimposed, indicating that the method was unlikely to resolve adequately the volatile hydrocarbons formed during irradiation. Using SPME-MDGC-MS 1-tetradecene (C(1-14:1)), n-pentadecane (C(15:0)), 1-hexadecene (C(1-16:1)), n-heptadecane (C(17:0)) and 8-heptadecene (C(8-17:1)) were detected in cooked ham irradiated at 0.5, 2, 4 and 8kGy. This method allows the detection of most n-alkanes and n-alkenes produced during the irradiation of the majority of fatty acids in cooked ham, namely oleic acid, stearic acid and palmitic acid. SPME is rapid and inexpensive and does not require organic solvents. The proposed SPME-MDGC-MS method allows the determination of radiolytic markers in cooked ham in less than 115min.

The role of fatty acids in anti-inflammatory effects of low-intensity extremely high-frequency electromagnetic radiation.

The effects of low-intensity extremely high-frequency electromagnetic radiation (EHF EMR; 42.2 GHz, 0.1 mW/cm(2) , exposure duration 20 min) on the fatty acid (FA) composition of thymic cells and blood plasma in normal mice and in mice with peritoneal inflammation were studied. It was found that the exposure of normal mice to EHF EMR increased the content of polyunsaturated FAs (PUFAs) (eicosapentaenoic and docosapentaenoic) in thymic cells. Using a model of zymosan-induced peritoneal inflammation, it was shown that the exposure of mice to EHF EMR significantly increased the content of PUFAs (dihomo-γ-linolenic, arachidonic, eicosapentaenoic, docosapentaenoic, and docosahexaenoic) and reduced the content of monounsaturated FAs (MUFAs) (palmitoleic and oleic) in thymic cells. Changes in the FA composition in the blood plasma were less pronounced and manifested themselves as an increase in the level of saturated FAs during the inflammation. The data obtained support the notion that MUFAs are replaced by PUFAs that can enter into the thymic cells from the external media. Taking into account the fact that the metabolites of PUFAs are lipid messengers actively involved in inflammatory and immune reactions, we assume that the increase in the content of n-3 and n-6 PUFAs in phospholipids of cellular membranes facilitates the realization of anti-inflammatory effects of EHF EMR.

The effective atomic number revisited in the light of modern photon-interaction cross-section databases.

The effective atomic number, Z(eff), has been calculated for fatty acids and cysteine. It is shown that Z(eff) is a useful parameter for low-Z materials at any energy above 1 keV. Absorption edges of medium-Z elements may complicate the energy dependence of Z(eff) below 10 keV. The notion of Z(eff) is perhaps most useful at energies where Compton scattering is dominating, and where Z(eff) is equal to the mean atomic number, Z, over a wide energy range around 1 MeV.

Influence of bleaching by ultrasound on fatty acids and minor compounds of olive oil. Qualitative and quantitative analysis of volatile compounds (by SPME coupled to GC/MS).

The effects of bleaching using high power ultrasound (20 kHz) on the quality of olive oil were considered in this study, in order to verify the modifications that can occur in fatty acid composition and minor compounds. During the treatment of olive oil under ultrasonic waves, a rancid odour has been detected. Treated olive oils show no significant changes in their chemical composition but the presence of some volatile compounds, due to ultrasonic treatment. Some off-flavour compounds (hexanal, hept-2-enal and 2(E),4(E)-decadienal) resulting from the sonodegradation of olive oil have been identified. A wide variety of analytical techniques (GLC, HPLC and GC/MS) were used to follow the quality of bleached olive oils with ultrasonic waves by the determination of the amounts of certain minor compounds such as sterols and tocopherols. Steradienes, resulting from the dehydration of sterols, were detected with small quantities especially in severe conditions of sonication. Solid phase micro-extraction (SPME) coupled to gas chromatography was known to be a sensitive technique to follow changes in the oxidative state of vegetable oils by measuring the amount of volatile materials produced during the refining process.

Analysis of radiation-induced hydrocarbons and 2-alkylcyclobutanones from dried shrimps (Penaeus aztecus).

We investigated the usefulness of hydrocarbons and 2-alkylcyclobutanones as markers for irradiated, dried shrimps. A method was developed to detect the irradiation of dried shrimps (Penaeus aztecus) by identifying radiation-induced hydrocarbons and 2-alkylcyclobutanones extracted from dried shrimps, which were separated by Florisil column chromatography and identified by a method using gas chromatography/mass spectrometry. Radiation-induced hydrocarbons and 2-alkylcyclobutanones are formed from the fatty acids of the irradiated fats. The quantity of the hydrocarbons and 2-alkylcyclobutanones formed from some fatty acids is related to the composition of fatty acids in a sample. The concentrations of hydrocarbons and 2-alkylcyclobutanones increased with radiation dose. The major hydrocarbons in the irradiated, dried shrimps were 1-tetradecene and pentadecane from palmitic acid; small amounts of heptadecane and 1-hexadecene from stearic acid; and 8-heptadecene and 1,7-hexadecadiene from oleic acid. 2-(5'-Tetradecenyl)cyclobutanone, one of the 2-alkylcyclobutanones, was present at the highest concentration. The radiation-induced hydrocarbons and 2-alkylcyclobutanones were detected at radiation doses of 0.5 kGy and greater. These compounds were not detected in nonirradiated, dried shrimps.

The cell membrane as a biosensor of oxidative stress induced by radiation exposure: a multiparameter investigation.

The role of biological membranes as a target in biological radiation damage remains unclear. The present study investigates how the biochemical and biophysical properties of a simple biological model, i.e. human erythrocyte membranes, are altered after exposure to relatively low doses of (60)Co gamma rays. Lipid peroxidation increased in the hours after radiation exposure, based on measurements of MDA and on the lipid peroxidation index after parinaric acid incorporation. Protein carbonyl content also increased rapidly after radiation exposure. An imbalance between the radiation-mediated oxidative damages and the antioxidant capacity of the erythrocytes was observed in the hours after radiation exposure. Antioxidant enzyme activities, mainly catalase and glutathione peroxidase, were found to decrease after irradiation. The development of a radiation-induced oxidative stress probably explains the reorganization of the fatty acid pattern 72 h after radiation exposure. The phosphatidylethanolamine (PE) fatty acids of the (n-3) and (n-6) series decreased, while the PE saturated fatty acid content increased. All these modifications may be involved in the variation of the biophysical properties of the membranes that we noted after radiation exposure. Specifically, we observed that the lipid compartment of the membrane became more fluid while the lipid-protein membrane interface became more rigid. Taken together, these findings reinforce our understanding that the cell membrane is a significant biological target of radiation. Thus the role of the biological membrane in the expression and course of cell damage after radiation exposure must be considered.

Detection of radiation-induced hydrocarbons and 2-alkylcyclobutanones in irradiated perilla seeds.

The method consists of the extraction of fat from perilla seeds, separation of hydrocarbons and 2-alkylcyclobutanones with florisil column chromatography, and identification of hydrocarbons and 2-alkylcyclobutanones by gas chromatography-mass spectroscopy (GC-MS). Concentrations of hydrocarbons and 2-alkylcyclobutanones increased with the irradiation dose. The major hydrocarbons in the irradiated perilla seeds were 8-heptadecene and 1,7-hexadecadiene from oleic acid and 6,9-heptadecadiene and 1,7,10-hexadecatriene from linoleic acid. One of the 2-alkylcyclobutanones, 2-(5'-tetradecenyl)cyclobutanone, was found in the highest concentration in the irradiated perilla seeds. Radiation-induced hydrocarbons in the perilla seeds were detected at doses of 0.5 kGy and higher, and radiation-induced 2-alkylcyclobutanones were detected at doses of 1 kGy and higher. These compounds were not detected in nonirradiated perilla seeds.

[Modification by cystamine of radiation-induced free radical damage to biomolecules in tissues of mouse organs]. / Modifikatsiia tsistaminom radiatsionnykh svobodnoradikal'nykh povrezhdenii biomolekul v tkaniiakh organov myshei.

The method of low-temperature ESR-spectroscopy was used to study a modifying effect of cystamine on the yield of radiation-induced free radicals in different biomolecules of liver and spleen tissues of mice. Intraperitoneal administration of cystamine (150 mg/kg) 15 min before isolation and freezing of the tissues was shown to reduce by 11 per cent the yield of radicals of H-adducts of thymine DNA bases, to decrease by 23 per cent the yield of radicals of triacyglycerol and phospholipid radiolysis, and to increase by 24 per cent the yield of radicals of lipid fatty acid residues in splenic tissue. According to the criterion used, cystamine has no modifying action on the yield of free-radical damages to liver biomolecules.

An evaluation of the contribution of membrane lipids to protection against ultraviolet radiation.

Using dioleoylphosphatidylcholine liposomes incorporating various fatty acids and neutral lipids, we have examined the ability of such lipids to provide protection of Escherichia coli and vesicular stomatitis virus (VSV) against the lethal effect of ultraviolet (254 nm) radiation. While the presence of varying amounts of saturated (palmitic) or polyunsaturated (arachidonic) fatty acids or the lipid antioxidant, alpha-tocopherol, had little effect on killing by ultraviolet radiation, considerable radioprotection was observed with beta-carotene, retinal and vitamin K-1 at final concentrations of 1 mg/ml. In another approach, vesicular stomatitis virus grown under conditions in which its envelope fatty acid composition was substantially modified, showed little change in its sensitivity to inactivation by ultraviolet radiation. The results provide strong evidence for a radioprotective role of certain, relatively rare natural lipid components with conjugated polyene systems, but not of the more ubiquitous and abundant membrane fatty acids.

[Effect of ionizing radiation on the lipid fatty acid composition of the plasma membranes of liver cells]. / Deistvie ioniziruiushchei radiatsii na zhirnokislotnyi sostav lipidov plazmaticheskikh membran kletok pecheni.

Changes in the fatty acid composition of total lipids and individual phospholipids of liver cell plasma membranes of intact and exposed (7.65 Gy) rats have been studied. The authors discuss the relationship between the degree of lipid oxidation and other lipid characteristics of the studied membrane after exposure to ionizing radiation.

[The role of lipid components of microsomal membranes of hepatocytes of the central Asian turtle in the actualization of radiation injuries]. / Rol' lipidnykh komponentov mikrosomal'nykh membran gepatotsitov sredneaziatskoi cherepakhi v realizatsii luchevykh povrezhdenii.

Phase changes in the content of biomembrane lipids and in the rate of their peroxidation were observed in liver microsomes of Testudo horsfieldi irradiated with a dose of 129.10(-1) C/kg. It is suggested that the decrease in the formation of peroxidation products of a diene series at the initial stage of radiation sickness are conditioned by the decrease in the activity of the key enzyme systems which regulate biosynthesis of polyunsaturated fatty acids, while the increase in the sphingomyelin level activates the lipid-dependent enzymes which repair the injured membranes.

Radiation studies of Acholeplasma laidlawii: the role of membrane composition.

Acholeplasma laidlawii, a mycoplasma, is unable to synthesize unsaturated fatty acids but it will incorporate them into its plasma membrane if they are supplied exogeneously. Thus the fatty acid composition of the cell membrane can be defined by growing the organism in media containing specific fatty acids. We obtained cells with predominantly one type of unsaturated fatty acid (either oleic, linoleic or linolenic acid) or cells with only saturated fatty acid in the cell membrane. The cells were irradiated with 7 MeV electrons and the effect of membrane fatty acid composition on cell survival was examined. At 200 Gy/min and 0.5 degrees C (melting ice) there was little difference in the radiation sensitivities of the cells grown in unsaturated fatty acids either in aerated or anoxic radiation conditions. However, the cells containing saturated fatty acids irradiated in anoxic conditions were markedly more sensitive than the cells containing unsaturated fatty acids. At 200 Gy/min and 37 degrees C the two types of cells were of similar sensitivity both in aerated and anoxic radiation conditions. At 5 Gy/min at 0.5 degrees C the cells containing linolenic acid (18:3) were less sensitive than those containing solely saturated fatty acids. However, at 5 Gy/min at 37 degrees C there was no difference in sensitivity between these two types of cell. Our results strongly argue against the involvement of lipid peroxidation as a molecular change leading to cell death.

A study of the peroxidation of fatty acid micelles promoted by ionizing radiation, hydrogen peroxide and ascorbate.

the kinetics of peroxidation of fatty acid micelles promoted by ionizing radiation, hydrogen peroxide and ascorbate were compared. At the dose-rate range of ionizing radiation studied, the higher the dose-rate, the greater the total dose required to produce the same effect. With ascorbate, the rate of lipid peroxidation was dependent on the concentration of the promoter only up to 1 X 10(-4) M, beyond which a decreasing rate of peroxidation induction was observed. Higher concentration of ascorbate also suppressed the promoting effect of ionizing radiation. Formate, a hydroxyl radical scavenger, inhibited the peroxidation process promoted by these three agents. Caesium was found to be slightly inhibitory. EDTA and deoxycholate were also inhibitory, which may be attributed to iron-chelating and micelle-disrupting capacity, respectively. Addition of iron (Fe2+ or Fe3+) to EDTA-chelated fatty acid micelles re-initiated the peroxidation process. The ease of fatty acid oxidation at pH 7.5 was arochidonic (20:4) greater than linolenic (18:3) greater than linoleic (18:2). This order was reversed at pH 11.5. Similarities in the kinetics of peroxidation obtained suggest that certain biological sequelae encountered in cells treated with these seemingly dissimilar agents might arise through some common mechanism(s).