Measuring sunscreen protection against solar-simulated radiation-induced structural radical damage to skin using ESR/spin trapping: development of an ex vivo test method.

The in vitro star system used for sunscreen UVA-testing is not an absolute measure of skin protection being a ratio of the total integrated UVA/UVB absorption. The in vivo persistent-pigment-darkening method requires human volunteers. We investigated the use of the ESR-detectable DMPO protein radical-adduct in solar-simulator-irradiated skin substitutes for sunscreen testing. Sunscreens SPF rated 20+ with UVA protection, reduced this adduct by 40-65% when applied at 2 mg/cm(2). SPF 15 Organic UVA-UVB (BMDBM-OMC) and TiO(2)-UVB filters and a novel UVA-TiO(2) filter reduced it by 21, 31 and 70% respectively. Conventional broad-spectrum sunscreens do not fully protect against protein radical-damage in skin due to possible visible-light contributions to damage or UVA-filter degradation. Anisotropic spectra of DMPO-trapped oxygen-centred radicals, proposed intermediates of lipid-oxidation, were detected in irradiated sunscreen and DMPO. Sunscreen protection might be improved by the consideration of visible-light protection and the design of filters to minimise radical leakage and lipid-oxidation.

Electron beam irradiation improves shelf lives of Korean ginseng (Panax ginseng C.A. Meyer) and red ginseng.

Effect of electron beam irradiation on microbial growth and qualities of vacuum-packaged Korean ginseng and red ginseng during storage was investigated. Korean ginseng and red ginseng were treated at irradiation doses of 0, 2, 8, and 16 kGy. After treatment, samples were individually vacuum-packaged and stored at 20 degrees C. Microbial growth results of the irradiated samples presented that populations of total bacteria, yeast and mold, and total coliforms were decreased by 2 to 3 log CFU/g. The pH values of the samples were not significantly different among treatments. Thiobarbituric acid-reactive substance values of the samples increased during storage. Electron beam treatment caused negligible changes in Hunter's color L, a, and b values among the samples. Sensory evaluations like color and odor of the samples exhibited that there were no significant changes among the samples. During storage, content of saponin, a leading compound in ginseng, was not affected by irradiation. These results suggest that electron beam treatment should be useful in extending shelf lives of Korean ginseng and red ginseng.

[Laser correction of microcirculation disorders in patients having CHD with hypercholesterinemia].

The study demonstrates that hypercholesterinemia in patients with coronary heart disease (CHD) is associated with functional depression of microcirculation, increase in total peripheral vascular resistance, reduction in the functional efficiency of heart and decrease in activity tolerance. After receiving a course of low-intensity infrared laser radiation treatment the patients displayed positive changes in blood lipid spectrum, which was associated with improvement in microcirculation, decrease in afterload, increase in economization of heart functioning and activity tolerance. The obtained results demonstrate that the hypolipidemic effect of laser radiation is a substantial factor in the regression of CHD manifestations.

Screening for new antioxidative compounds for topical administration using skin lipid model systems.

PURPOSE: The effects of forty seven different substances (drugs, plant extracts, plant ingredients and polysaccharides) on UV irradiation induced lipid peroxidation were investigated. METHODS: Two lipid systems of different complexity were used as in vitro screening models. Iron ions were added as transition metal catalysts. A UV irradiation device was used to create high level radiation. The amount of lipid peroxidation secondary products was quantified by the thiobarbituric acid assay detecting malondialdehyde. RESULTS: The screening for antioxidative compounds for topical administration resulted in new, interesting findings. In the drug testings amantadine, bufexamac, tryptophan, melatonin, propranolol and hyaluronic acid were found to act antioxidatively whereas for ascorbic acid pro-oxidative effects were determined. Buckwheat extract significantly reduced the level of irradiation induced lipid peroxidation as well as the extracts of St. John's Wort, melissa and sage. The resistant starch novelose 330 and the samples of locust bean gum from a swing mill grinding series showed lipid protection after UV irradiation in the polysaccharide test rows. CONCLUSIONS: Human skin is constantly exposed to UV light and oxygen. Therefore, the administration of protectors in cosmetic formulations or sunscreens, as found in this study, may be helpful for the protection of the human skin against UV induced damage. In vivo experiments with substances found as protectors should follow to allow in vitro-in vivo correlation and clinical interpretation of the data.

[Structural changes in lipid membranes and collagen irradiated with UV light and the protective effect of plant extracts]. / Strukturnye izmeneniia lipidnykh membran i kollagena, obluchennye UF-svetom, i zashchitnoe deistvie rastitel'nykh ékstraktov.

The results of experimental studies on the effect of UV irradiation on collagen, artificial lipid membranes, and rat skin, as well as the protective effect of plant extracts from UV radiation are presented. The irradiation of collagen and lipid membranes with solar and artificial UV light leads to structural changes in these objects. In particular, collagen molecules denature and transfer into a new conformational state. The effect of UV light on lipid membranes and liposomes leads to a disturbance of membrane structure, which is connected with a decrease in the number of lipid molecules involved in the cooperative transition from gel into a liquid crystal state. The components of plant extracts (mainly flavonoids) absorb UV radiation in the erythem-forming spectral area and block the destructive processes occurring in collagen and lipids.

Structural and biochemical basis for the UVB-induced alterations in epidermal barrier function.

Ultraviolet light (UVR) induces a myriad of cutaneous changes, including delayed disruption of the permeability barrier with higher doses. To investigate the basis for the UVB-induced barrier alteration, we assessed the epidermal lamellar body secretory system at various time points before and after barrier disruption with a single high dose of UVB (7.5 MED) to murine epidermis. Morphological data were correlated with changes in epidermal proliferation and lipid synthesis, indicative of lamellar body generation. Twenty-four hours following UVB, the stratum corneum (SC) is normal, but a layer of abnormal, vacuolated, and lamellar body (LB)-deficient cells is present, immediately beneath the stratum granulosum (SG)/SC interface. Immediately subjacent to this band of damaged cells, normal keratinocytes that contain intact LBs are present. By 72 h, concomitant with the appearance of a barrier abnormality, extensively damaged cells persist at the SC/SG interface, and abnormal lamellar membrane structures appear in the lower SC. Upper stratum spinosum (SS) and lower SG cells appear normal, with increased numbers of LBs. A barrier abnormality is still present at 96 h, in association with membrane abnormalities in the lower SC interstices, but up to four normal appearing, subjacent SG cell layers are present. By 120 h, accelerated LB formation and precocious LB extrusion occur throughout the thickened SG; normal lamellar membranes are present in the lower SC; and barrier recovery is almost complete. Whereas, epidermal synthesis of the major barrier lipid species (i.e., cholesterol, fatty acids, and ceramides, including acylceramides) is reduced or unchanged at 24 and 48 h, it increases significantly 72 h after exposure to UVB. Therefore, the delayed disruption of the permeability barrier following acute UVB exposure results from the arrival of a band of lamellar body-incompetent (i.e., damaged) cells at the SG/SC interface. The subsequent, rapid recovery of the barrier, in turn, results from compensatory hyperplasia of subjacent, undamaged SS/SG cells, generating increased numbers and contents of LB. These results underscore the critical role of the stratum compactum in mediating barrier function, and suggest that beneficial therapeutic effects of UV exposure may be due to enhanced lipid production and barrier regeneration.

Enhancement of microbiological safety levels of aseptically admixed total parenteral nutrition solutions through low-dose gamma irradiation.

This study was undertaken to determine the effect of low-dose gamma irradiation on aseptically admixed total parenteral nutrition (TPN) solutions to which large inocula of three test bacterial species were added. Microbiological safety levels were quantified in terms of sterility assurance levels (SALs), indicating the probability of contamination occurring expressed as 10-n. The radiation sensitivity (D10 values) of test bacteria in TPN solutions inoculated with a series of bacteria recognized as common contaminants of these products, was determined. Attainable SALs of TPN solutions containing test bacteria were subsequently calculated from the D10 values. Results showed that a minimum absorbed radiation dose as low as 1.5 kGy improved the SAL of aseptically prepared TPN solutions from a probability value of 10(-3) to a value of less than 10(-8) for the microorganisms investigated. At an absorbed dose as high as 8.3 kGy, no measurable changes in amino acid, electrolyte, glucose and lipid components of the solutions were detected. These findings have important implications for the enhancement of microbiological safety levels of aseptically prepared intravenous fluids in general.

[The catalase activity and lipid peroxidation of donor blood under ultraviolet irradiation]. / Katalaznaia aktivnost' i perekisnoe okislenie lipidov donorskoi krovi pri ul'trafioletovom obluchenii.

Under study were catalase activity and indicators of lipid peroxidation (LP) of donor blood exposed to different doses of UV irradiation. Doses lower than 630 J/m2 were found to activate catalase and to inhibit LP while doses higher than 630 J/m2 inhibited catalase activity and activated LP. The indicators of LP have confirmed that therapeutic doses of UV-irradiated blood were nontoxic. The most optimal therapeutic dose of irradiation (630 J/m2) was determined.

[Clinico-biochemical parallels against a background of traditional treatment and laser therapy of patients with ischemic heart disease]. / Kliniko-biokhimicheskie paralleli na fone traditsionnogo lecheniia i lazeroterapii bol'nykh ishemicheskoi bolezn'iu serdtsa.

The paper is devoted to analysis of clinico-biochemical indices and a quest for additional pathologico-chemical criteria at the cell membrane level of the efficacy of helium-neon laser therapy in coronary heart disease (CHD). Another task was to decipher a number of metabolic signs of the phenomenon of CHD "exacerbation" in laser therapy (during 4-6 sessions). Positive clinical results were obtained in 98% of the patients. A favorable time course was noted in serum lipoprotein spectrum indices and in lipid and phospholipid structure of erythrocyte membranes. Laser therapy caused mobilization of the cell membrane antioxidant defense. The 4th-6th session of irradiation was marked by temporary clinical deterioration--"exacerbation" of disease accompanied by an increase in the level of erythrocyte total phospholipids (at the expense of PTEA), a decrease in free fatty acid deficiency against a background of advancing alpha-tocopherol deficiency and a rise of the blood level of lipid peroxidation primary products (diene conjugates). A conclusion was that membrane protective drugs and drugs enhancing cell energy and antioxidant defense resources promoting the "deactivation" of influence on the membrane of lipid peroxidation metabolites (tocopherol, Essentiale, retinol, etc.) should be incorporated in therapy of CHD in order to prevent the phenomenon of its "exacerbation".

The effects of ionizing radiation on the peroxide content of a pure polyunsaturated lipid dispersion and of lipids and membranes derived from Acholeplasma laidlawii.

Dispersions of a pure unsaturated phospholipid, dilinoleoylphosphatidyl choline, formed conjugated diene hydroperoxides when irradiated in air with 7 MeV electrons (150 Gy and 300 Gy). Peroxide formation was optimized when the dispersions were irradiated in air at 37 degrees C at a dose rate of 5 Gy/min. No significant loss of linoleic acid from the irradiated phospholipid dispersions was observed after doses of 150 or 300 Gy. Small amounts of thiobarbituric acid-reactive material were formed in irradiated unsaturated phospholipid dispersions. However, lipids or membranes isolated from 48 hour cultures of Acholeplasma laidlawii grown in media supplemented with either linoleic or linolenic acid did not appear to be peroxidized by irradiation under the same conditions.

New concepts in phototherapy: photoisomerization of bilirubin IX alpha and potential toxic effects of light.

New information is summarized, indicating that configurational photoisomerization of bilirubin at the 5 and 15 carbon bridges is the major mechanism of bilirubin photocatabolism in vivo, and that singlet oxygen photooxidation plays only a minor role. The literature is reviewed concerning potentially damaging photodynamic reactions that are observed in vitro with vitamins, proteins, lipids, and nucleic acids, and their possible relationships to the limited number of toxic side-effects that have been detected with clinical phototherapy of neonatal jaundice. Secondary toxic effects, mediated by bilirubin photoderivatives or by retina-neuroendocrine pathways are also considered. Areas requiring further investigations are delineated.

Reactivation of the lipid-depleted pyruvate oxidase system from Escherichia coli with cell envelope neutral lipids.

The pyruvate oxidase system of Escherichia coli is composed of a soluble flavoprotein, pyruvate oxidase (EC 1.2.2.2, pyruvate:ferricytochrome b1 oxidoreductase), and an electron transport system associated with the cell envelope-membrane fraction. The membrane particles contain 15% lipid by weight. Fractionation of the lipids revealed that abut one-third are neutral lipids and two-thirds are phospholipids. The relative ratio of ubiquinone to menaquinone within the neutral lipid fraction is 15:1 on a molar basis. Removal of the lipids from the membrane particles by extraction with aqueous acetone or hydrolysis of the phospholipids by treatment with Bacillus cereus phospholipase C results in a complete loss of electron transport activity. Analysis of the particles extracted with aqueous acetone revealed that practically all the neutral lipids and 65% of the phospholipids are removed by this treatment. Phospholipase treatment results in a loss of 75% of the membrane phospholipid phosphorus; however, the diglycerides and the neutral lipids produced by phospholipase hydrolysis remain associated with the particles. Addition of neutral lipid and a detergent, hepta-DL-alanyl dodecylamide to the acetone-extracted material results in a restoration of 37% of the original particle activity. Addition of neutral lipid and hepta-DL-alanyl dodecylamide to phospholipase-treated particles completely restores the original electron transport activity. Furthermore, addition of ubiquinone from either yeast (UQ6) or E. coli (UQ8) will restore pyruvate oxidase activity when the quinones are supplemented with photoinactivated neutral lipid. No restoration of activity to phospholipase-treated particles is noted upon the addition of either menaquinone 6 or menaquinone 8 to the reconstitution system. In fact, these compounds appear to suppress restoration of activity when they are added to reaction mixtures containing neutral lipid and phospholipase-treated particles.

Mutagenicity and cytotoxicity of irradiated foods and food components.

The preservation of foods by treatment with ionizing radiation can significantly increase the world's food resources by reducing spoilage and waste. However, irradiation can bring about chemical transformations in food and food components resulting in the formation of potential mutagens, particularly hydrogen peroxide and various organic peroxides. In order to evaluate the safety of irradiated foods for general consumption by the public, and, indeed, the safety of all foods subjected to environmental factors such as food additives, pesticides, drugs, air and water pollutants, etc., it is necessary to supplement the usual feeding tests with procedures designed to detect all classes of genetic damage. This article includes a comprehensive critical review of (1) the experimental evidence relating to the presence of mutagenic and cytotoxic agents in irradiated media, as detected by their effects on mammalian and non-mammalian cells; (2) the chemical changes produced in irradiated media, especially those which produce known mutagenic substances; and (3) new and convenient in vivo methods for the detection and evaluation of genetic damage in mammals.