TiO2 Nanomaterials Non-Controlled Contamination Could Be Hazardous for Normal Cells Located in the Field of Radiotherapy

Among nanomaterials (NMs), titanium dioxide (TiO2) is one of the most manufactured NMs and can be found in many consumers’ products such as skin care products, textiles and food (as E171 additive). Moreover, due to its most attractive property, a photoactivation upon non-ionizing UVA radiation, TiO2 NMs is widely used as a decontaminating agent. Uncontrolled contaminations by TiO2 NMs during their production (professional exposure) or by using products (consumer exposure) are rather frequent. So far, TiO2 NMs cytotoxicity is still a matter of controversy depending on biological models, types of TiO2 NMs, suspension preparation and biological endpoints. TiO2 NMs photoactivation has been widely described for UV light radiation exposure, it could lead to reactive oxygen species production, known to be both cyto- and genotoxic on human cells. After higher photon energy exposition, such as X-rays used for radiotherapy and for medical imaging, TiO2 NMs photoactivation still occurs. Importantly, the question of its hazard in the case of body contamination of persons receiving radiotherapy was never addressed, knowing that healthy tissues surrounding the tumor are indeed exposed. The present work focuses on the analysis of human normal bronchiolar cell response after co-exposition TiO2 NMs (with different coatings) and ionizing radiation. Our results show a clear synergistic effect, in terms of cell viability, cell death and oxidative stress, between TiO2 NMS and radiation.

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The Structure and Photochromism of 2,4,4,6-Tetraphenyl-4H-thiopyran

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19921326 ◽

1992 ◽

Vol 57 (6) ◽

pp. 1326-1334 ◽

Cited By ~ 11

Author(s):

Jaroslav Vojtěchovský ◽

Jindřich Hašek ◽

Stanislav Nešpůrek ◽

Mojmír Adamec

Keyword(s):

Solid State ◽

Uv Light ◽

Order Reaction ◽

Boat Conformation ◽

X Rays ◽

Exponential Time ◽

First Order ◽

Double Plane ◽

The Mean ◽

Independent Molecules

2,4,4,6-Tetraphenyl-4H-thiopyran, C29H22S, orthorhombic, Pna21, a = 17.980(4), b = 6.956(2), c = 34.562(11) Å, V = 4323(2) Å3, Z = 8, Dx = 1.237 g cm-3, F(000) = 1696, λ(CuKα) = 1.54184 A, μ = 1.372 mm-2, T = 294 K. The final R was 0.050 for the unique set of 3103 observed reflections. The central 4H-thiopyran ring forms a boat conformation for both symmetrically independent molecules with average boat angles 4.4(3) and 6.8(3)° at S and C(sp3), respectively. The mean planes of phenyls at the position 2 and 6 are turned from the double plane of 4H-thiopyran by 42.5(5) and 35.8(3)°, respectively. The investigated material undergoes a photochromic change in the solid state after irradiation with UV light or X-rays. The maximum of the new absorption band is situated at 564 nm. The non-exponential time dependence of photochromic bleaching is analysed in terms of a dispersive first-order reaction.

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Absence of interaction between X-rays and UV light in inducing ouabain- and thioguanine-resistant mutants in Chinese hamster cells

Mutation Research/Fundamental and Molecular Mechanisms of Mutagenesis ◽

10.1016/0027-5107(78)90145-8 ◽

1978 ◽

Vol 52 (2) ◽

pp. 247-253 ◽

Cited By ~ 19

Author(s):

James E. Cleaver

Keyword(s):

Uv Light ◽

Chinese Hamster ◽

X Rays ◽

Chinese Hamster Cells ◽

Resistant Mutants

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Conductivity of polyethylene induced by pulsed UV light, fast electrons and X-rays

Seventh International Conference on Dielectric Materials, Measurements and Applications ◽

10.1049/cp:19960997 ◽

1996 ◽

Cited By ~ 1

Author(s):

K. Hodyr

Keyword(s):

Uv Light ◽

X Rays ◽

Fast Electrons ◽

Pulsed Uv Light

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Cytochemische Untersuchungen zur Reproduktion des Tabakmosaikvirus

Zeitschrift für Naturforschung B ◽

10.1515/znb-1961-0806 ◽

1961 ◽

Vol 16 (8) ◽

pp. 520-538 ◽

Cited By ~ 15

Author(s):

Hendrik Zech

Keyword(s):

Electric Fields ◽

Uv Light ◽

Refraction Index ◽

Optical Measurements ◽

Uv Spectrophotometry ◽

X Rays ◽

Optical Absorbance ◽

Wide Range ◽

Light Losses

Crystalline or paracrystalline tobacco mosaic virus (TMV) inclusions are known to be composed mainly of densely packed TMV-rods. These inclusions were studied in situ within infected tobacco leaf hair cells by scanning UV-microspectrophotometry. Comparative measurements in the macroand micro ranges of the instruments were carried out on purified TMV at low and high concentrations, on its separated and reconstituted RNA and protein parts and on isolated TMV-crystals, to permit the interpretation of the optical properties of TMV inclusions in situ. The optical absorbance of TMV in solution and in dried concentrates at room temperature could in part be attributed to distribution inhomogeneities caused by local particle aggregations being oriented to differing degrees. The resulting non-uniform electric fields around and within such unevenly distributed particle complexes caused local jumps of the refraction index and thereby unspecific light losses, chiefly through scattering. The apparent deviation from Beers law was found to be greatest at particle concentrations of 1 - 2 per cent. At higher concentrations the contribution of scatter to light losses was found to decrease again, probably because of increasing order of particles within the aggregates. On the other hand the specific absorbance of the chromophores of TMV over a wide range of concentration was not affected to a measurable degree by changing the distances between the rods. There was no indication that the charged groups of the RNA-cores within intact particles interacted with charged groups of other particles however great their proximity. The ribose phosphate backbone of the RNA strand, deeply embedded within the protein helix, may account for this phenomenon. However, isolated TMV-RNA reacted strongly to changes of the surrounding electric fields when concentrations were varied, and showed pronounced hypochromicity at higher concentrations and following prolonged irridation by x-rays and UV-light. RNA in dried and irradiated droplets was characterized by up to 55% lower extinction coefficients than freshly prepared RNA in solution. The hyprochromic effects caused by irradiation were shown to be almost, but not completely reversible. Hypochromicity increased towards the shorter wavelengths, diminishing the ratio E260/E280 from about 2.0 for diluted RNA to 1.4 for concentrated specimens. Mixing TMV-protein subunits with RNA before drying, leading to partial reconstitution of TMV particles, diminished the hypochromic effect resulting from irradiation of the concentrate. High UV-radiation doses applied to concentrated TMV solutions led to a marked splitting of RNA from protein, as revealed by UV-spectrophotometry of the supernatants and pellets of centrifuged irradiated specimens. Model measurements of intracellular and subsequently isolated TMV crystals combined with empirically derived parameters led to the construction of a correction curve, permitting interpretations of optical measurements on in situ TMV inclusion bodies.

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Effects of Nanoparticle Size and Radiation Energy on Copper-Cysteamine Nanoparticles for X-ray Induced Photodynamic Therapy

Nanomaterials ◽

10.3390/nano10061087 ◽

2020 ◽

Vol 10 (6) ◽

pp. 1087

Author(s):

Bindeshwar Sah ◽

Jing Wu ◽

Adam Vanasse ◽

Nil Kanatha Pandey ◽

Lalit Chudal ◽

...

Keyword(s):

Radiation Therapy ◽

Reactive Oxygen Species Production ◽

Radiation Energy ◽

Nanoparticle Size ◽

Oxygen Species ◽

X Rays ◽

Therapy Outcomes ◽

X Ray ◽

Average Size ◽

Species Production

The Copper-cysteamine (Cu-Cy) nanoparticle is a novel sensitizer with a potential to increase the effectiveness of radiation therapy for cancer treatment. In this work, the effect of nanoparticle size and the energy of X-rays on the effectiveness of radiation therapy are investigated. The effect of the particle size on their performance is very complicated. The nanoparticles with an average size of 300 nm have the most intense photoluminescence, the nanoparticles with the average size of 100 nm have the most reactive oxygen species production upon X-ray irradiation, while the nanoparticles with the average size of 40 nm have the best outcome in the tumor suppression in mice upon X-ray irradiation. For energy, 90 kVp radiation resulted in smaller tumor sizes than 250 kVp or 350 kVp radiation energies. Overall, knowledge of the effect of nanoparticle size and radiation energy on radiation therapy outcomes could be useful for future applications of Cu-Cy nanoparticles.

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Thermoluminescence of irradiated ammonium perchlorate crystals

Canadian Journal of Physics ◽

10.1139/p76-088 ◽

1976 ◽

Vol 54 (7) ◽

pp. 766-770 ◽

Cited By ~ 2

Author(s):

S. Radhakrishna ◽

M. Riggin ◽

P. W. Whippey ◽

P. W. M. Jacobs

Keyword(s):

Absorption Spectrum ◽

Single Crystals ◽

Heating Rate ◽

Ammonium Perchlorate ◽

Uv Light ◽

High Energy ◽

X Rays ◽

Spectroscopic Evidence ◽

Additional Peak ◽

High Energy Electrons

The thermoluminescence of single crystals of ammonium perchlorate irradiated with X rays, uv light, or high energy electrons has been measured between 80 and 420 K. With a heating rate of 5 K/min. prominent peaks occur at 95, 113, 134, 246, and 320 K; an additional peak is found at 347 K after longer irradiation times. The absorption spectrum of uv-irradiated ammonium perchlorate has also been measured and shows bands at 300, 360, and 610 nm. A comparison of these data with chemical and spectroscopic evidence obtained by other workers has permitted the probable identification of ClO3−, ClO−, ClO2, and F centres as radiation products. Three thermoluminescent peaks remain unassigned.

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Assessment of DNA Damage after Photodynamic Therapy Using a Metallophthalocyanine Photosensitizer

International Journal of Photoenergy ◽

10.1155/2012/281068 ◽

2012 ◽

Vol 2012 ◽

pp. 1-10 ◽

Cited By ~ 17

Author(s):

A. El-Hussein ◽

M. Harith ◽

H. Abrahamse

Keyword(s):

Dna Damage ◽

Photodynamic Therapy ◽

Adaptive Response ◽

Uv Light ◽

Cell Types ◽

Surrounding Tissue ◽

Target Tissue ◽

X Rays ◽

Integrity Of Dna ◽

Mcf 7

Photodynamic therapy (PDT) is a chemotherapeutic approach that utilizes a bifunctional reagent, a photosensitizer (PS) that localizes to the target tissue relative to the surrounding tissue and is toxic when exposed to laser light. PDT rapidly induces cell death, inflammatory and immune reactions, and damage of the microvasculature. DNA damage results from a variety of factors including UV-light, X-rays, ionizing radiation, toxins, chemicals, or reactive oxygen species. The aim of this study was to determine the effect of PDT as well as the influence of presensitization leading to the adaptive response (AR) on the integrity of DNA. Lung (A549), breast (MCF-7), and esophageal (SNO) cancer cells and Zn sulfophthalocyanine as PS with irradiation conditions of 10 J/cm2at 636 nm were used. Subcellular localization of PS, cell morphology, and viability after PDT and DNA damage were determined. A significant decrease in viability and marked DNA damage was observed in all 3 cancer cell types in response to PDT while the adaptive response was demonstrated to significantly decrease the effectiveness of the PDT.

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Direct observation of various reaction pathways of arylnitrenes in different crystal environments caused by acid–base complex formation

Acta Crystallographica Section B Structural Science ◽

10.1107/s010876811003661x ◽

2010 ◽

Vol 66 (6) ◽

pp. 647-661 ◽

Cited By ~ 10

Author(s):

Takahiro Mitsumori ◽

Akiko Sekine ◽

Hidehiro Uekusa ◽

Yuji Ohashi

Keyword(s):

Complex Formation ◽

Structural Changes ◽

Uv Light ◽

Reaction Pathway ◽

Crystal Form ◽

X Rays ◽

Acid Base ◽

Base Complex ◽

X Ray ◽

Complex Crystals

The structures of reaction intermediates, arylnitrenes and their final products have been successfully analyzed by X-rays using acid–base complex formation. The acid–base complexes of 2-azidobenzoic acid (2a), 3-azidobenzoic acid (3a) and 4-azidobenzoic acid (4a) were made with dibenzylamine (db), N-benzyl-2-phenylethylamine (bp) and dicyclohexylamine (dc). For the complex crystals of (3a) and db (3a-db), and (4a) and db (4a-db) two forms of (I) and (II) were obtained. Eight types of complex crystals, (2a-db), (3a-db-I), (3a-db-II), (3a-dc), (4a-db-I), (4a-db-II), (4a-bp) and (4a-dc), suitable for X-ray analysis were obtained. When the crystals were irradiated with UV light at low temperatures, the reactions proceeded keeping the single-crystal form in the five crystals (2a-db), (3a-db-I), (3a-db-II), (3a-dc) and (4a-bp). Less than 25% of each azidobenzoic acids was transformed into an arylnitrene and dinitrogen. In three crystals the arylnitrenes produced gave new final products; 2,1-benzisoxazolone was observed for (2a-db) and trans-azobenzenes (i.e. dimerized nitrenes) were obtained for (3a-db-II) and (4a-bp). For (3a-db-I) and (3a-dc) the intermediate arylnitrenes were observed but did not transform to new products. All the structural changes were directly observed by X-ray analysis because the incomplete reactions occurred with retention crystallinity. The crystal environment, including the hydrogen bonding between the benzoic acid and the amine, places restrictions on the movement of the arylnitrene and influences the reaction pathway followed for conversion of the arylnitrene to its final product.

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