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Photochemistry and Photobiology

Jacob R Herschmann, Aqeeb Ali, Michele Harris, Matthew McClinton, Matibur Zamadar
Here we report an experimental study of the effect of toxic metal ions on photosensitized singlet oxygen generation for photodegradation of PAH derivatives, Anthracene-9,10-dipropionic acid disodium salt (ADPA) and 1,5-dihydroxynapthalene (DHN) and photoinactivation of E. coli bacteria by using cationic meso-tetra(N-methyl-4-pyridyl)porphine tetrachloride (TMPyP) as a singlet oxygen photosensitizer. Three s-block metals ions, such as Na+ , K+ , and Ca2+ and five toxic metals such as Cd2+ , Cu2+ , Hg2+ , Zn2+ , and Pb2+ were studied...
November 17, 2018: Photochemistry and Photobiology
María V de Gálvez, José Aguilera, Cristina Sánchez-Roldán, Enrique Herrera-Acosta, Enrique Herrera-Ceballos
The potential role of infrared radiation in photodermatoses has received very little attention, even though the main sources of radiation used for photobiological studies (UVA, UVB, and visible light) include infrared radiation. The objective of the work was assess whether infrared radiation is involved in the development of skin lesions in patients with different types of photodermatoses. Twenty patients with different photodermatoses were exposed to UVA, UVB, and visible radiation using a high pressure mercury UVA lamp, a fluorescent broadband UVB lamp, a tungsten bulb and a slide projector for visible radiation...
November 17, 2018: Photochemistry and Photobiology
Lucas Andreo, Carla A Soldera, Beatriz Guimarães Ribeiro, Patrick Raoul Vicente de Matos, Paola Bindes Sousa, Weslley Wallace de Alcântara Araújo Amorim, Anna Carolina Ratto Tempestini Horliana, Sandra Kalil Bussadori, Kristianne Porta Santos Fernandes, Raquel Agnelli Mesquita-Ferrari
A peripheral nerve injury (PNI) can result in motor or sensory disorders. Low-level laser therapy (LLLT) has demonstrated positive results as a treatment option for PNI. Wistar rats were divided into five groups: Control, Injury, Injury+LLLTn (nerve), Injury+LLLTm (muscle) and Injury+LLLTn+m (nerve and muscle irradiation). The groups were analyzed after one, two, three and four weeks. PNI was achieved by crushing the sciatic nerve. Laser treatment (780nm, 3.2J) was realized over the nerve and/or tibialis anterior muscle...
November 9, 2018: Photochemistry and Photobiology
Carolina Castaño, Mariana P Serrano, Carolina Lorente, Claudio D Borsarelli, Andrés H Thomas
Unconjugated oxidized pterins accumulate in the skin of patients suffering from vitiligo and, under UV-A irradiation, photosensitize the oxidation of amino acids. In this work we study the interaction of the singlet and triplet excited states of pterin (Ptr), the parent compound of oxidized pterins, with four oxidizable amino acids: tryptophan (Trp), tyrosine (Tyr), histidine (His) and methionine (Met). Steady-state and time-resolved fluorescence measurements and laser flash photolysis experiments were performed to investigate the quenching of the Ptr excited states by the amino acids in aqueous solution...
November 7, 2018: Photochemistry and Photobiology
Eduardo Gatica, David Possetto, Agustina Reynoso, José Natera, Miskoski Sandra, Eduardo De Geronimo, Mabel Bregliani, Adriana Pajares, Walter A Massad
The pro-herbicide Isoxaflutole (IXF) hydrolyses spontaneously to diketonitrile (DKN) a phytotoxic compound with herbicidal activity. In this work, the sensitized degradation of IXF using Riboflavin (Rf), a typical environmentally friendly sensitizer, Fenton and photo-Fenton processes have been studied. The results indicate that only the photo-Fenton process produces a significant degradation of the IXF. Photolysis experiments of IXF sensitized by Riboflavin is not a meaningful process, IXF quenches the Rf excited triplet (3 Rf*) state with a quenching rate constant of 1...
November 7, 2018: Photochemistry and Photobiology
Jean Cadet, J Richard Wagner, Dimitar Angelov
Oxidation reactions triggered by low intensity UV photons represent a minor contribution with respect to the overwhelming pyrimidine base dimerization in both isolated and cellular DNA. The situation is totally different when DNA is exposed to high intensity UVC radiation under conditions were bi-photonic ionization of the four main purine and pyrimidine bases becomes predominant at the expense of singlet excitation processes. The present review article provides a critical survey of the main chemical reactions of the base radical cations thus generated by one-electron oxidation of nucleic acids in model systems and cells...
October 31, 2018: Photochemistry and Photobiology
Rachel C Chiaroni-Clarke, Jane E Munro, Angela Pezic, Joanna E Cobb, Jonathan D Akikusa, Roger C Allen, Terence Dwyer, Anne-Louise Ponsonby, Justine A Ellis
Cutaneous sun exposure is an important determinant of circulating vitamin D. Both sun exposure and vitamin D have been inversely associated with risk of autoimmune disease. In juvenile idiopathic arthritis (JIA), low circulating vitamin D appears common, but disease-related behavioural changes may have influenced sun exposure. We therefore aimed to determine whether pre-disease sun exposure is associated with JIA. Using validated questionnaires, we retrospectively measured sun exposure for 202 Caucasian JIA case-control pairs born in Victoria Australia, matched for birth year and time of recruitment...
October 31, 2018: Photochemistry and Photobiology
Kota Ohashi, Yusuke Kinoshita, Hitoshi Tamiaki
C3-(Trans-arylethenyl)carbonylated chlorophyll derivatives possessing a bacteriochlorin or chlorin π-system were synthesized by cross-aldol (Claisen-Schmidt) condensation of methyl pyrobacteriopheophorbide-a or 3-acetyl-3-devinyl-pyropheophorbide-a bearing the C3-acetyl group with p-(un)substituted benzaldehydes under basic conditions. The corresponding porphyrin-type chlorophyll derivatives were prepared by the oxidation (17,18-didehydrogenation) of the chlorin-type. Their Qy absorption and fluorescence emission maxima in dichloromethane correlated well with Hammett substituent constants of the p-substituents...
October 31, 2018: Photochemistry and Photobiology
Erin C Tracy, Mary-Jo Bowman, Ravendra K Pandey, Heinz Baumann
This study determined in primary cultures of human lung cancer cells the cell specificity of chlorin-based photosensitizers. Epithelial cells (EC) preferentially retained 3-[1-hexyloxyethyl]-2-devinylpyropheophorbide-a (HPPH) and related structural variants. Tumor-associated fibroblasts (Fb) differ from EC by a higher efflux rate of HPPH. Immunoblot analyses indicated dimerization of STAT3 as a reliable biomarker of the photoreaction. Compared to mitochondria/ER-localized photoreaction by HPPH, the photoreaction by lysosomally targeted HPPH-lactose showed a trend toward lower STAT3 crosslinking...
October 31, 2018: Photochemistry and Photobiology
Natália Cestari Moreno, Camila Carrião Machado Garcia, Clarissa Ribeiro Reily Rocha, Veridiana Munford, Carlos Frederico Martins Menck
The crucial role of DNA polymerase eta in protecting against sunlight-induced tumors is evidenced in Xeroderma Pigmentosum Variant (XP-V) patients, who carry mutations in this protein and present increased frequency of skin cancer. XP-V cellular phenotypes may be aggravated if proteins of DNA Damage Response (DDR) pathway are blocked, as widely demonstrated by experiments with UVC light and caffeine. However, little is known about the participation of DDR in XP-V cells exposed to UVA light, the wavelength patients are mostly exposed...
October 25, 2018: Photochemistry and Photobiology
Richard W Davis, Emma Snyder, Joann Miller, Shirron Carter, Cassandra Houser, Astero Klampatsa, Steven Albelda, Keith Cengel, Theresa M Busch
Inflammatory cells, most especially neutrophils, can be a necessary component of the anti-tumor activity occurring after administration of photodynamic therapy. Generation of neutrophil responses has been suggested to be particularly important in instances when the delivered PDT dose is insufficient. In these cases, the release of neutrophil granules and engagement of anti-tumor immunity may play an important role in eliminating residual disease. Herein, we utilize in vivo imaging of luminol chemiluminescence to non-invasively monitor neutrophil activation after PDT administration...
October 25, 2018: Photochemistry and Photobiology
Kenneth F Stensrud, Kimberly J Zanotti, Alan S Waggoner, Bruce A Armitage
Spectral properties and fluorogenic behaviors of five novel thiophene variants of Malachite Green (MG), termed MGTs, were determined. Appreciable changes as a function of homologation and substitution pattern, including absorption band positions and intensities and fluorescence quantum yields were observed. In particular, the shorter wavelength y-band absorption was found to shift over a nearly 200 nm range based on aryl group variation, allowing fine-tuning of the excitation wavelength for these dyes. In addition, the fluorescence intensity of some MGTs increased significantly (up to 4,600-fold) when the dye was bound to a cognate protein partner, which is potentially useful for cell imaging studies...
October 19, 2018: Photochemistry and Photobiology
Yan Jun Ma, Chun Xiao Sun, Jian Wen Wang
Hypocrellin A (HA), a promising photosensitizer for anticancer photodynamic therapy (PDT), is a fungal perylenequinone pigment from the fruiting body of Shiraia bambusicola, a traditional Chinese medicine for treating skin diseases. The mycelial cultures are becoming a biotechnological alternative for HA production. In this study, light of different wavelengths was investigated to develop an effective eliciting strategy for HA production in the cultures. Under red LED light (627 nm) at 200 lux, the maximum HA production (175...
October 19, 2018: Photochemistry and Photobiology
Genji Imokawa
Exposure of human skin to ultraviolet (UV) radiation causes significant damage to that tissue. The effects of UV on the skin mainly include acute inflammation (erythema/edema) and abnormal keratinization wherein prostaglandin E2 (produced by cyclooxygenase-2), interleukin-8 and transglutaminase 1 (a major regulatory factor of keratinization), play pivotal roles. Later phases of UV-induced skin reactions include hyperpigmentation, wrinkle formation and carcinogenesis, the former two being associated with the UVB-induced production and/or secretion of endothelin-1, stem cell factor and granulocyte macrophage colony stimulatory factor by keratinocytes in the epidermis...
October 19, 2018: Photochemistry and Photobiology
Genji Imokawa
In the first review, we summarized the biological effects of the xanthophyll carotenoid astaxanthin (AX) to prevent UV-induced cutaneous inflammation, abnormal keratinization, pigmentation and wrinkling in a manner independent of the depletion of reactive oxygen species. In this manuscript, we review what is known about the intracellular signaling mechanisms that are involved in those effects in keratinocytes and in melanocytes. Our research has characterized the intracellular stress signaling mechanism(s) that are involved in the up-regulated expression of genes encoding cyclooxygenase (COX2), interleukin (IL)-8, granulocyte macrophage colony stimulatory factor (GM-CSF) and transglutaminase (TGase)1 in UVB-exposed keratinocytes as well as in the stimulated transcription and/or translation of melanogenic factors, including microphthalmia-associated transcription factor (MITF), in stem cell factor (SCF)-treated melanocytes...
October 13, 2018: Photochemistry and Photobiology
Christopher Grieco, Forrest R Kohl, Yuyuan Zhang, Sangeetha Natarajan, Lluís Blancafort, Bern Kohler
The catechol functional group plays a major role in the chemical properties of a wide variety of molecules important in biology and technology. In eumelanin, intermolecular hydrogen bonding between these functional groups is thought to contribute to UV photoprotective and radical buffering properties, but the mechanisms are poorly understood. Here, aggregates of 4-t-butylcatechol are used as model systems to study how intermolecular hydrogen bonding influences photochemical pathways that may occur in eumelanin...
October 13, 2018: Photochemistry and Photobiology
Micaela E Grassano, Marcela S Altamirano, María P Militello, Ernesto M Arbeloa, Carlos M Previtali, Sonia G Bertolotti
The photophysical and photochemical properties of the xanthene dyes mercurochrome (MCr) and eosin-Y (Eos); and the phenazine dye safranine-O (SF) are evaluated in the presence of amino-terminated polyamidoamine (PAMAM) dendrimers of low generations. The dendrimers produce a red shift in the UV-vis absorption spectra of the dyes, which increases with concentration and the size of the PAMAM molecule. The Stern-Volmer plots of fluorescence quenching for xanthenic dyes present a downward curvature. It is ascribed to a static mechanism involving a dye-dendrimer binding...
October 12, 2018: Photochemistry and Photobiology
Michael J Doughty
The goal of this review was to identify and discuss the specialized methods that have been used to assess the corneas of the eyes of living rabbits exposed to the damaging effects of UV-B. From publications reviewed between 1916 and 2018, both albino and pigmented rabbits were used, usually being young adults weighing between 2 and 2.5 kg, and with many recent studies carried out under sedation. Older assessments were generally based on the use of in vivo slitlamp examinations, sometimes with the use of fluorescein or rose bengal to identify damaged cells, supported by light microscopy (histology) of excised corneas...
October 3, 2018: Photochemistry and Photobiology
Andrea Amaroli, Sara Ferrando, Stefano Benedicenti
After 50 years of studies on photobiomodulation (PBM) there is still so much to investigate to understand the laser-light - non-plant cells interactions. The current scientific knowledge allows to say that the phenomena induced by PBM are based on cellular pathways that are key points of cell life. The mitochondria chromophores, also present on the bacterial membrane, the calcium channels, ion that regulates the life-and-death cellular processes, as well as the TRP-family, whose genes have been found in protozoa and suggest that its basic mechanism evolved long before the appearance of animals, seem to be elective targets in photobiomodulatory events by wavelengths from 600 nm up to 980 nm...
October 3, 2018: Photochemistry and Photobiology
Elineides Santos Silva, Gabriela Benedito Machado, Adriana Lino-Dos-Santos-Franco, Christiane Pavani
Natural extracts (NE) with antioxidant properties can minimize the effects of photoaging. Photobiomodulation (PBM) has proven to be a useful tool for the modulation of cell metabolism. Here, we investigate the associations of antioxidants with PBM with the aim of promoting skin rejuvenation. We began with standardization of the experimental protocol. Extracts of chamomile, rosemary, blueberry, green tea, figs, pomegranate and nutwood were tested. A custom irradiation system (366 ± 10 nm) was used to simulate sun exposure...
September 29, 2018: Photochemistry and Photobiology
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