Induction of primary cutaneous melanomas in C3H mice by combined treatment with ultraviolet radiation, ethanol and aloe emodin

The role of ultraviolet (UV) radiation in the induction of nonmelanoma skin cancer is widely accepted, although its precise contribution to the development of primary cutaneous melanoma skin cancer requires further definition. We found that painting aloe emodin, a trihydroxyanthraquinone from Aloe barbadensis, in ethyl alcohol vehicle on the skin of mice in conjunction with exposure to UVB (280-320 nm) radiation results in the development of melanin-containing skin tumors. C3H/HeN mice were treated thrice weekly with aloe emodin in a 25% ethanol in water vehicle and exposed to 15 kJ/m2 UV radiation. Neither ethanol vehicle nor aloe emodin alone induced skin tumors in the absence of UV radiation. In two separate experiments, 20-30% of the mice treated with a combination of UV radiation and ethanol vehicle and 50-67% of the UV-irradiated animals given aloe emodin in ethanol vehicle developed primary cutaneous melanin-containing tumors. The diagnosis of melanoma was established using Fontana silver stain for melanin; these tumors were negative for vimentin and keratin. Melanin-containing melanosomes were observed by transmission electron microscopy in tumors diagnosed as melanomas. Although the mechanism of carcinogenesis in these mice is currently unknown, our findings have led to the development of the first facile murine model for the induction of primary melanoma. This model has the potential to clarify the role of UV radiation in the etiology of malignant melanoma.     

Exposure to increased ambient ultraviolet B radiation has negative effects on growth, condition and immune function of juvenile Atlantic salmon (Salmo salar)

Atlantic salmon (Salmo salar) parr were exposed in two outdoor experiments, ranging in duration from 52 to 137 days, to spectral treatments: (1) natural sunlight (=present ambient UVB level), (2) solar radiation supplemented with enhanced UVB radiation from lamps simulating 20% or 8% stratospheric ozone loss or (3) UVB-depleted sunlight achieved by screening with Mylar-D film. The growth, condition and immune function of the salmon were quantified after treatments. Exposure to enhanced UVB radiation retarded growth, and decreased hematocrit value and plasma protein concentration. Further, enhanced UVB radiation affected plasma immunoglobulin concentration. The results demonstrate that juvenile Atlantic salmon are not able to fully adapt to increased ambient UVB levels in long-term exposures, and the interference with immune system function suggests a negative effect of UVB on disease resistance in Atlantic salmon.     

Fluorescence line-narrowing spectroscopy of fluorene and naphthalene with second-harmonic generated ultraviolet radiation

Second-harmonic generated u.v. radiation from an argon-ion pumped CW dye laser is used to yield highly resolved fluorescence line-narrowed spectra of fluorene and naphthalene in 3-methylpentane at 10 K and 5 K, respectively. The results suggest that the applicability of the method can be widely extended.     

Neutrophil infiltration in normal human skin after exposure to different ultraviolet radiation sources

Exposure of the skin to UV radiation can lead to a local infiltration of neutrophils. Not much is known on whether the infiltration of neutrophils in the irradiated skin is UV source dependent. In this study we compared different UV sources (solar-simulated radiation [SSR], narrowband [NB]-UVB, broadband [BB]-UVB and UVA1) in their potency to induce neutrophil infiltration in normal human skin after exposure to two times the minimal erythema dose of UV radiation. Biopsies were collected from irradiated buttock skin 6 and 24 h after irradiation and from nonirradiated skin. The presence, distribution and amount of skin-infiltrated neutrophils were determined using immunohistochemical staining. Analysis revealed that SSR was most effective in inducing neutrophil infiltration. NB-UVB gave a neutrophil influx pattern similar to that seen with SSR but in smaller numbers. BB-UVB and UVA1 were far less potent in inducing neutrophil infiltration compared with SSR or NB-UVB. Our findings indicate that neutrophil infiltration in the UV-irradiated skin is UV source dependent. When the spectra emitted by the different UV sources were compared UVB seemed to be more effective than UVA in inducing neutrophil infiltration. Furthermore, our results suggest that longer wavelengths within the UVB range are mostly responsible for the infiltration of neutrophils in the UV-irradiated skin.     

Photoionization of epichlorohydrin enantiomers and clusters studied with circularly polarized vacuum ultraviolet radiation

The photoionization of enantiomerically pure epichlorohydrin (C(3)H(5)OCl) has been studied using linearly and circularly polarized vacuum ultraviolet synchrotron radiation. The threshold photoelectron spectrum was recorded and the first three bands assigned using molecular orbital calculations for the expected conformers, although uncertain experimental conformer populations and an anticipated breakdown in Koopmans' theorem leave some ambiguity. Measurements of the photoelectron circular dichroism (PECD) were obtained across a range of photon energies for each of these bands, using electron velocity map imaging to record the angular distributions, during which a record PECD chiral asymmetry factor of 32% was observed. A comparison with calculated PECD curves clarifies the assignment achieved using ionization energies alone and further suggests a likely relative population of the conformers. Threshold photoelectron-photoion coincidence methods were used to study the ionic fragmentation of epichlorohydrin. Fragment ion appearance energies show nonstatistical behavior with clear indications that the cationic epoxide ring is unstable and lower energy decay channels proceeding via ring breaking are generally open. Extensive neutral homochiral clusters of epichlorohydrin may be formed in supersonic molecular beam expansions seeded in Ar. Electron angular distribution measurements made in coincidence with dimer and trimer ions are used to effect an examination of the PECD associated with ionization of size-selected neutral cluster species, and these results differ clearly from PECD of the neutral monomer. The shifted ionization thresholds of the n-mers (n = 2, ..., 7) are shown to follow a simple linear relationship, but under intense beam expansion conditions the monomer deviates from this relationship, and the monomer electron spectra tail to below the expected monomer adiabatic ionization potential (IP). PECD measurements made in coincidence with monomer ions obtained under different beam expansion conditions were used to identify unambiguously a contribution from dissociative photoionization of larger clusters to the monomer parent mass ion yield above and below its adiabatic IP.     

Overview of the inactivation by 254 nm ultraviolet radiation of bacteria with particular relevance to biodefense

Abstract Our goal was to ultimately predict the sensitivity of untested bacteria (including those of biodefense interest) to ultraviolet (UV) radiation. In this study, we present an overview and analysis of the relevant 254 nm data previously reported and available in the literature. The amount of variability in this data prevented us from determining an "average" response for any bacterium. Therefore, we developed particular selection criteria to include the data in our analysis and suggested future guidelines for reporting UV sensitivity results. We then compiled a table of the sensitivity to 254 nm UV for 38 bacteria and three bacterial spores. The UV sensitivity was quite similar (within 10%) among the spores of Bacillus anthracis (strains Vollum 1B and Sterne), Bacillus subtilis, and Bacillus megaterium. These data indicate that spores of B. subtilis and B. megaterium could be adequate simulants of B. anthracis spores in UVC experiments. Spores of B. anthracis, B. subtilis and B. megaterium were 5-10 times more resistant to UV than were their corresponding vegetative cells. The vegetative cells of B. anthracis showed similar UV sensitivity to those of Burkholderia pseudomallei, Shigella sonnei, and a wild-type strain of Escherichia coli. Yersinia enterocolitica and Vibrio cholerae appeared more sensitive to UV and Salmonella typhi slightly more resistant to UV than E. coli. The sensitivity (at 254 nm) of all vegetative bacteria ranged from 11 to 80 Jm(2) for a 1 Log(10) kill and from 25-200 Jm(2) for 4 Log(10) kill.     

Vertical mixing and ecological effects of ultraviolet radiation in planktonic communities

We present a mathematical model for a phytoplankton-zooplankton system, based on a predator-prey scheme. The model considers the effects of sinking in the phytoplankton, vertical mixing and attenuation of photosynthetically active radiation (PAR) and ultraviolet radiation (UVR) in the water column. In a first approach, the model was studied under conditions of average PAR irradiance and shows fluctuations and stable equilibrium points. Secondly, we introduced the effects of photoperiod and photoinhibition by UVR and vertical mixing. Under these conditions, the phytoplankton biomass oscillates depending on the combined effects of UVR and mixing. Higher inhibition by UVR and longer mixing periods can induce strong fluctuations in the system but can also produce higher plankton peaks.     

Differential scanning calorimetry of chloroquine sulphate exposed to sun,heat and ultraviolet radiation

Chloroquine sulphate, like the phosphate, is an antimalarial formulation widely used in the tropics. The stability of such formulations is therefore of interest in the combat against malaria. A DSC study has been made of the effects of exposure to the sun, heat and UV radiation on the stability of chloroquine sulphate, similarly as performed earlier for chloroquine phosphate. When freshly recrystallized from a water-acetone mixture, chloroquine sulphate exhibits two endothermic peaks, at 169.4° and 204.7°, for the expulsion of crystal water (one molecule) and for the melting process, respectively. The exposure of chloroquine sulphate to the sun, heat and UV radiation leads to splitting of the peak for melting.

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Zusammenfassung Chloroquine-Sulfat ist ebenso wie das entsprechende Phosphatderivat ein in den Tropen weitverbreitet angewandtes Antimalaria-Präparat. Die Stabilität dieses Präparates hat damit Bedeutung für die Malariabekämpfung. Die vorliegende Arbeit ist eine Erweiterung einer Untersuchung über den Effekt der Einwirkung.von Sonne, Hitze und UV-Strahlen auf die Stabilität von Chloroquine-Phosphat auf Chloroquine-Sulfat. Aus Wasser-Aceton-Mischungen frisch kristallisiertes Chloroquine-Sulfat zeigt zwei endotherme Peaks bei 169,4 und 204,7 °C, die durch Abgabe von Kristallwasser (ein Molekül) bzw. durch den Schmelzvorgang bedingt sind. Wird Chloroquine-Sulfat der Sonne, Wärme oder UV-Licht ausgesetzt, so wird der dem Schmelzvorgang zuzuscheibende Peak aufgespalten.

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Influence of dietary menhaden oil upon carcinogenesis and various cutaneous responses to ultraviolet radiation

Abstract Recent reports suggest that eicosapentaenoic acid (EPA) inhibits growth of transplanted tumors and the formation of various chemically induced cancers in animals. Menhaden oil is a source of polyunsaturated lipid with a high content of EPA, an omega-3 fatty acid. We sought to explore the effects of menhaden oil on photocarcinogenesis by employing the hairless mouse/UV-carcinogenesis model. Five groups of 40 SKH-Hr-1 mice received (a) a semipurined equicaloric diet containing either 0.75% corn oil, 4% corn oil. 4% menhaden oil or 12% menhaden oil and (b) an escalating regimen of UV radiation to a cumulative dose of 70 J/cm². Additional animals were employed to further examine the role of menhaden oil in acute cutaneous responses to UV, i.e., erythema, edema, and ornithine decarboxylase (ODC) induction. After a 2-week feeding period UV-induced ODC activity in mice receiving 12 or 20% menhaden oil was 3 to 13-fold lower than that of corn oil fed animals. Further studies showed that edema was also markedly decreased. Animals receiving menhaden oil required twice the level of irradiance to evoke a comparable erythema as that which occurred in corn oil fed animals. Menhaden oil exerted significant influence upon carcinogenic expression, as manifested in significantly longer tumor latent periods and lower tumor multiplicities when compared to corn oil fed animals. Although the mechanism(s) of these menhaden oil effects remains unknown, it is clear that this unique lipid has a pronounced influence upon cutaneous photoresponses. 15th Annual Meeting of the American Society for Photobiology, Bal Harbor, FL, June, 1987.     

Occupational exposures to solar ultraviolet radiation of vineyard workers in Tuscany (Italy)

A study to quantify the UV exposure of vineyard workers was carried out using polysulphone dosimetry. The study took place in Tuscany (Italy) involving 32 vineyard workers, covering three different stages of the vine's growth. The level of personal exposure expressed as a function on the available ambient UV radiation was determined. We also assessed skin reflectance parameters, pre and post exposure. It was found that during spring backs received between 53% and 87% of ambient exposure and arms between 30% and 60%. During summer, the workers received on the back between 36% and 77% of ambient exposure and between 19% and 43% of ambient exposure on the arm. The comparison with the occupational UV exposure limit showed that all subjects received UV exposures in excess of the limit. The exposure of back of neck exceeded 10 SED (assumed as a threshold level of sun-adapted skin for Mediterranean subjects) in spring, which means that in the case of non sun-adapted skin and without sun protection, erythema can be induced in this targeted population. The cumulative exposure was also estimated under specific assumptions of UV exposure giving values in some cases higher than previous studies.     

Patterns of DNA damage and photoinhibition in temperate South-Atlantic picophytoplankton exposed to solar ultraviolet radiation.

Natural marine phytoplankton assemblages from Bahía Bustamante (Chubut, Argentina, 45 degrees S, 66.5 degrees W), mainly consisting of cells in the picoplankton size range (0.2-2 microm), were exposed to various UVBR (280-315 nm) and UVAR (315-400 nm) regimes in order to follow wavelength-dependent patterns of cyclobutane pyrimidine dimer (CPD) induction and repair. Simultaneously, UVR induced photosynthetic inhibition was studied in radiocarbon incorporation experiments. Biological weighting functions (BWFs) for photoinhibition and for CPD induction, the latter measured in bare calf thymus DNA, differed in the UVAR region: carbon incorporation was reduced markedly due to UVAR, whereas no measurable UVAR effect was found on CPD formation. In contrast, BWFs for inhibition of photosynthesis and CPD accumulation were fairly similar in the UVBR region, especially above 300 nm. Incubation of phytoplankton under full solar radiation caused rapid CPD accumulation over the day, giving maximum damage levels exceeding 500 CPD MB(-1) at the end of the afternoon. A clear daily pattern of CPD accumulation was found, in keeping with the DNA effective dose measured by a DNA dosimeter. In contrast, UVBR induced photosynthetic inhibition was not dose related and remained nearly constant during the day. Screening of UVBR or UVR did not cause significant CPD removal, indicating that photoreactivation either by PAR or UVAR was of minor importance in these organisms. High CPD levels were found in situ early in the morning, which remained unaffected notwithstanding treatments favoring photorepair. These results imply that a proportion of cells had been killed by UVBR exposure prior to the treatments. Our data suggest that the limited potential for photoreactivation in picophytoplankton assemblages from the southern Atlantic Ocean causes high CPD accumulation as a result of UVBR exposure.     

Molecular response to ultraviolet radiation exposure in fish embryos: implications for survival and morphological development

UVR exposure is known to cause developmental defects in a variety of organisms including aquatic species but little is known about the underlying molecular mechanisms. In this work we used zebrafish (Danio rerio) embryos as a model system to characterize the UVR effects on fish species. Larval viability was measured for embryos exposed to several UVR spectral treatments by using a solar simulator lamp and an array of UV cutoff filters under controlled conditions in the laboratory. Survival rate and occurrence of development abnormalities, mainly caudal (posterior) notochord bending/torsion, were seriously affected in UV-exposed larvae reaching values of 53% and 72%, respectively, compared with non-UV-exposed larvae after 6 days postfertilization (dpf). In order to elucidate the molecular mechanisms involved, a matricellular glycoprotein named osteonectin and the expression of a DNA-repair related gene, p53, were studied in relation to UVR exposure. The results indicate that osteonectin and p53 expression were increased under UVR exposure due to wavelengths shorter than 335 nm (i.e. mainly UVB) and 350 nm (i.e. short UVA and UVB), respectively. Furthermore, parallel experiments with microinjections of osteonectin-capped RNA showed that malformations induced by osteonectin overexpression were similar to those observed after a UVR exposure. Consequently this study shows a potential role of osteonectin in morphological deformities induced by solar UV radiation in zebrafish embryos.     

Daily and circadian variation in survival from ultraviolet radiation in Chlamydomonas reinhardtii

The survival of organisms depends on their ability to adapt to their environment, one important aspect of which is the daily cycle of day and night. During the day, organisms use a variety of strategies to protect themselves from deleterious ultraviolet (UV) wavelengths of sunlight. Among those strategies could be timing of UV-sensitive cellular processes to occur at night to avoid UV-induced damage. We tested whether the unicellular alga Chlamydomonas reinhardtii uses this strategy by measuring the survival of cells following exposure to UV radiation at different phases of the day. Chlamydomonas cells displayed a rhythm of survival from UV radiation where the most sensitive phases occurred during the end of the day and at the beginning of the night. This phase of sensitivity corresponds to the time of nuclear division. The rhythm continues in constant light indicating control by a circadian clock. The results presented here suggest a hypothesis of how circadian clocks may have evolved; a temporal program whereby light-sensitive processes are timed to avoid sunlight-induced damage would be advantageous and therefore selected.     

Estimating attenuation of ultraviolet radiation in streams: field and laboratory methods

We adapted and tested a laboratory quantitative filter pad method and field-based microcosm method for estimating diffuse attenuation coefficients (K(d)) of ultraviolet radiation (UVR) for a wide range of stream optical environments (K(d320) = 3-44 m(-1)). Logistical difficulties of direct measurements of UVR attenuation have inhibited widespread monitoring of this important parameter in streams. Suspended sediment concentrations were manipulated in a microcosm, which was used to obtain direct measurements of diffuse attenuation. Dissolved and particulate absorption measurements of samples from the microcosm experiments were used to calibrate the laboratory method. Conditions sampled cover a range of suspended sediment (0-50 mg L(-1)) and dissolved organic carbon concentrations (1-4 mg L(-1)). We evaluated four models for precision and reproducibility in calculating particulate absorption and the optimal model was used in an empirical approach to estimate diffuse attenuation coefficients from total absorption coefficients. We field-tested the laboratory method by comparing laboratory-estimated and field-measured diffuse attenuation coefficients for seven sites on the main stem and 10 tributaries of the Lehigh River, eastern Pennsylvania, USA. The laboratory-based method described here affords widespread application, which will further our understanding of how stream optical environments vary spatially and temporally and consequently influence ecological processes in streams.     

Sensitivity of molecular docking to induced fit effects in influenza virus neuraminidase

Many proteins undergo small side chain or even backbone movements on binding of different ligands into the same protein structure. This is known as induced fit and is potentially problematic for virtual screening of databases against protein targets. In this report we investigate the limits of the rigid protein approximation used by the docking program, GOLD, through cross-docking using protein structures of influenza neuraminidase. Neuraminidase is known to exhibit small but significant induced fit effects on ligand binding. Some neuraminidase crystal structures caused concern due to the bound ligand conformation and GOLD performed poorly on these complexes. A `clean' set, which contained unique, unambiguous complexes, was defined. For this set, the lowest energy structure was correctly docked (i.e. RMSD < 1.5 Å away from the crystal reference structure) in 84% of proteins, and the most promiscuous protein (1mwe) was able to dock all 15 ligands accurately including those that normally required an induced fit movement. This is considerably better than the 70% success rate seen with GOLD against general validation sets. Inclusion of specific water molecules involved in water-mediated hydrogen bonds did not significantly improve the docking performance for ligands that formed water-mediated contacts but it did prevent docking of ligands that displaced these waters. Our data supports the use of a single protein structure for virtual screening with GOLD in some applications involving induced fit effects, although care must be taken to identify the protein structure that performs best against a wide variety of ligands. The performance of GOLD was significantly better than the GOLD implementation of ChemScore and the reasons for this are discussed. Overall, GOLD has shown itself to be an extremely good, robust docking program for this system.     

Evaluating radiation risks and resource opportunities associated with phosphogypsum in the Philippines

Journal of Radioanalytical and Nuclear Chemistry - Phosphogypsum (PG) accumulates during wet-phosphoric acid production for fertilizers. In the Philippines, PG is partly (40%) utilized to produce...     

The protective effects of a d-tetra-peptide hydrogel adjuvant vaccine against H7N9 influenza virus in mice

Repeated waves of influenza virus H7N9 epidemics after 2013 have caused severe influenza in humans, with mortality reaching approximately 40%–50%. To prevent possible pandemics, the development of highly effective vaccines against influenza virus H7N9 is highly desired. In the present study, by taking advantage of the d-tetra-peptide adjuvant (G^DF^DF^DY), we reported a simple method to prepare H7N9 vaccines. Naproxen (Npx), with good anti inflammatory and broad anti-viral effects, was employed as an N-terminal capping group to construct a hydrogel precursor, Npx-G^DF^DF^DY. The hydrogel adjuvant was prepared using a routine heating cooling protocol and the final vaccine was ready after mixing with the split A/Zhejiang/DTID-ZJU01/2013 (H7N9) antigen by vortexing. Compared with the traditional Al(OH)₃ adjuvant vaccine and the split vaccine, our hydrogel adjuvant vaccine showed the best preventive effects against H7N9 infection. A mechanistic study illustrated that higher antibody responses and variations in cytokine expression might account for its increased protective effects. Our strategy demonstrated the advantages of a peptide hydrogel adjuvant in the application of vaccines against H7N9 and demonstrated its potential application in vaccines against emerging threats from other viruses.