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A continuous state of oxidative stress during inflammation contributes to the development of 25% of human cancers. Epithelial and inflammatory cells release reactive oxygen species (ROS) and reactive nitrogen species (RNS) that can damage DNA. ROS/RNS have biological implications in both chemoresistance and tumor recurrence. As several clinically employed anticancer drugs can generate ROS/RNS, we have addressed herein how inducible nitric oxide synthase and nitric oxide (iNOS/ • NO) affect the molecular pathways implicated in the tumor response to oxidative stress. To mimic the oxidative stress associated with chemotherapy, we used a photosensitizer (pheophorbide a) that can generate ROS/RNS in a controlled manner. We investigated how iNOS/ • NO modulates the tumor response to oxidative stress by involving the NF-κB and Nrf2 molecular pathways. We found that low levels of iNOS induce the development of a more aggressive tumor population, leading to survival, recurrence and resistance. By contrast, high levels of iNOS/ • NO sensitize tumor cells to oxidative treatment, causing cell growth arrest. Our analysis showed that NF-κB and Nrf2, which are activated in response to oxidative stress, communicate with each other through RKIP. For this critical role, RKIP could be an interesting target for anticancer drugs. Our study provides insight into the complex signaling response of cancer cells to oxidative treatments as well as new possibilities for the rational design of new therapeutic strategies., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Accumulating experimental evidence indicates that S-nitrosylation (technically S-nitrosation) events have a central role in plant biology, presumably accounting for much of the widespread influence of nitric oxide (NO) on developmental, metabolic, and stress-related plant responses. Therefore, the accurate detection and quantification of S-nitrosylated proteins and peptides can be particularly useful to determine the relevance of this class of compounds in the ever-increasing number of NO-dependent signaling events described in plant systems. Up to now, the quantification of S-nitrosothiols (SNOs) in plant samples has mostly relied on the Saville reaction and the ozone-based chemiluminescence method, which lacks sensitivity and are very time-consuming, respectively. Taking advantage of the photolytic properties of S-nitrosylated proteins and peptides, the method described in this chapter allows simple, fast, and high-throughput detection of SNOs in plant samples.

β-Endorphin exerts a broad spectrum of physiological activity on mood, immune functions, pain management, reward effects, and behavioral stability. β-Endorphin is produced in certain neurons within the central and peripheral nervous system but also in the skin, especially in response to ultraviolet radiation. In the present study we have investigated the impact of visible blue light at λ = 453 nm (BL) on β-endorphin production of primary human skin keratinocytes (hKC) in-vitro as well as on systemic β-endorphin formation of whole-body exposed subjects in-vivo. We found that BL irradiation significantly enhanced both keratinocytic β-endorphin production of hKC cultures as well as systemic β-endorphin concentrations in light exposed healthy subjects. Interestingly, in hKC cultures elevated β-endorphin formation was paralleled by significantly increased levels of non-enzymatically generated nitric oxide (NO), whereas elevated systemic β-endorphin values of BL-exposed subjects were accompanied by enhanced systemic concentration of bioactive NO-derivates. These findings point to a pivotal role of NO in the molecular mechanism of the observed BL-induced effects, and indeed, exogenously applied NO was able to significantly enhance β-endorphin production in hKC cultures. Thus, our finding of BL-induced increases in systemic β-endorphin concentration in-vivo can be plausibly explained by an event sequence comprising 1.) BL-driven non-enzymatic formation of NO in the exposed skin tissue, 2.) systemic distribution of cutaneously produced NO in the form of bioactive nitroso compounds, 3.) a subsequent NO-dependent induction of β-endorphin synthesis in epidermal keratinocytes, and 4.) probably also a NO-dependent modulation of β-endorphin synthesis in specialized neurons within the central and peripheral nervous system., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Ocular infection due to microbial contamination is one of the main risks associated with the wearing of contact lens, which demands novel straightforward strategies to find reliable solutions. This contribution reports the preparation, characterization and biological evaluation of soft contact lenses (CL) releasing nitric oxide (NO), as an unconventional antibacterial agent, under daylight exposure. A tailored NO photodonor (NOPD) was embedded into commercial CL leading to doped CL with an excellent optical transparency (transmittance = 100%) at λ ≥ 450 nm. The NOPD results homogeneously distributed in the CL matrix where it fully preserves the photobehavior exhibited in solution. In particular, NO release from the CL and its diffusion in the supernatant physiological solution is observed upon visible light illumination. The presence of a blue fluorescent reporting functionality into the molecular skeleton of the NOPD, which activates concomitantly to the NO photorelease, allows the easy monitoring of the NO delivery in real-time and confirms that the doped CL work under daylight exposure. The NO photoreleasing CL are well-tolerated in both dark and light conditions by corneal cells while being able to induce good growth inhibition of Staphylococcus aureus under visible light irradiation. These results may pave the way to further engineering of the CL with NOPD as innovative ocular devices activatable by sunlight.

The skin provides an effective barrier against physical, chemical, and microbial invasion; however, overexposure to ultraviolet (UV) radiation causes excessive cellular oxidative stress, which leads to skin damage, DNA damage, mutations, and skin cancer. This study investigated the protective effects of N -phenethyl caffeamide (K36) from UVA damage on human epidermal keratinocytes. We found that K36 reduced UVA-induced intracellular reactive oxygen species (ROS) production and induced the expression of the intrinsic antioxidant enzyme heme oxygenase-1 (HO-1) by increasing the translocation of nuclear factor erythroid 2⁻related factor 2 (Nrf2). K36 could inhibit the phosphorylation of extracellular-signal-regulated kinase (ERK) and c-Jun N-terminal kinases (JNK) and reduce UVA-induced matrix metalloproteinase (MMP)-1 and MMP-2 overexpression; it could also elevate the expression of tissue inhibitors of metalloproteinases (TIMP). In addition, K36 ameliorated 8-hydroxy-2'-deoxyguanosine (8-OHdG) induced by UVA irradiation. Furthermore, K36 could downregulate the expression of inducible nitric oxide synthase (iNOS) and interleukin-6 (IL-6) and the subsequent production of nitric oxide (NO) and prostaglandin E₂ (PGE₂). Based on our findings, K36 possessed potent antioxidant, anti-inflammatory, antiphotodamage, and even antiphotocarcinogenesis activities. Thus, K36 has the potential to be used to multifunctional skin care products and drugs.

The study examined the effects of millimeter electromagnetic waves at a frequency of 130 GHz corresponding to the molecular absorption and radiation spectra of NO and O 2 with the total exposition time of 6 h on tumor morphogenesis in 3- and 6-month-old tumor-prone BALB/c mice of both sexes. In experimental mice exposed to electromagnetic radiation, the development of cancer process was slowed down throughout the observation period; moreover, no macroscopic signs of the tumors were revealed. However, in contrast to control mice, experimental animals demonstrated the formation of pathological reactions reflected by hepatic biochemical indices accompanied by the development of dystrophic and microcirculatory alterations in the liver tissue.

Herein, a mesoporous nanoplate multi-directional assembled Bi 2 WO 6 architecture was successfully prepared and applied for the photocatalytic removal of NOx pollutants at low concentrations under visible light and simulated solar light irradiation. Bi 2 WO 6 -180-C synthesized at a hydrothermal temperature of 180 °C with calcination exhibited an excellent conversion efficiency in the photocatalytic oxidation of gaseous NO. The crystallinity, morphology, specific surface area, pore environment, light absorption, and separation of photogenerated electrons and holes were investigated by various techniques; the excellent photocatalytic performance of Bi 2 WO 6 -180-C was attributed to its special hierarchical mesoporous structure with an appropriate pore size and interconnected porous network, which imparted good gas permeability and fast mass transfer of reaction intermediates and final products of NO oxidation. Furthermore, hierarchical mesoporous Bi 2 WO 6 showed excellent photocatalytic durability and reusability., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Objectives: The aim of this study was to detect the influences of LA at nonacupoint and two adjacent acupoints of pericardium meridian on the releases of NO and sGC in 20 healthy subjects., Methods: Different intensities (12, 24, 48 mW) of infrared laser were used for irradiating Jianshi (PC5), Ximen (PC4) acupoints and nonacupoint for 20, 40 minutes, respectively. Semi-circular tubes were taped to the skin surface and filled with NO-scavenging compound for 20 minutes to capture NO and sGC, which were measured using spectrophotometry in a blinded fashion., Results: As the increase in the intensity of LA stimulation, the levels of NO releases over acupoints all were significantly increased, NO releases in nonacupoints following the same treatment only changed slightly, sGC amounts were observably enhanced over acupoints, but did not any change in nonacupoint area. Different intensities of LA treatments can sensitively affect the NO and sGC releases over acupoints. This indicated that LA-induced releases of the NO and sGC were specific to acupoints., Conclusions: This is the first evidence reporting that LA induced significant elevations of NO-sGC releases over acupoints, and the enhanced signal molecules contribute to local circulation, which improves the beneficial effects of the therapy., (© 2017 John Wiley & Sons Ltd.)

The effect of low-level laser therapy (LLLT) on the cardiovascular system is not fully established. Since the endothelium is an important endocrine element, establishing the mechanisms of LLLT action is an important issue.The aim of the study was to evaluate the effect of transdermal LLLT on endothelial function.In this study, healthy volunteers (n = 40, age = 20-40 years) were enrolled. N = 30 (14 female, 16 male, mean age 30 ± 5 years) constituted the laser-irradiated group (LG). The remaining 10 subjects (6 women, 4 men, mean age 28 ± 5 years) constituted the control group (CG). Participants were subjected to LLLT once a day for three consecutive days. Blood for biochemical assessments was drawn before the first irradiation and 24 h after the last session. In the LG, transdermal illumination of radial artery was conducted (a semiconductor laser λ = 808 nm, irradiation 50 mW, energy density 1.6 W/cm(2) and a dose 20 J/day, a total dose of 60 J). Biochemical parameters (reflecting angiogenesis: vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), angiostatin; antioxidative status: glutathione (GSH) and the nitric oxide metabolic pathway: symmetric dimethylarginine (SDMA), asymmetric dimethylarginine (ADMA) and L-arginine) were assessed. In the LG, a significant increase in GSH levels and considerable decrease in angiostatin concentration following the LLLT were observed. No significant differences in levels of the VEGF, FGF, SDMA, ADMA were observed.LLLT modifies vascular endothelial function by increasing its antioxidant and angiogenic potential. We found no significant differences in levels of the nitric oxide pathway metabolites within 24 h following the LLLT irradiation., Competing Interests: Compliance with ethical standards Ethics statement All experiments were conducted and approved in accordance with the guidelines of the Bioethics Committee at Wroclaw Medical University and adhered to the principles of the Declaration of Helsinki and Title 45, U.S. Code of Federal Regulations, Part 46, Protection of Human Subjects (revised November 13, 2001, effective December 13, 2001). All participants provided their written consent to participate in the study. The written consent form had been approved by the ethics committee. The study has been registered in the European Medicines Agency Clinical Trial and has been assigned under number 2016-001024-63. Conflict of interest The authors declare that they have no conflict of interest.

The objective of the this study was to evaluate the effects of cellular phone radiation on oxidative stress parameters and oxide levels in mouse brain during pentylenetetrazole (PTZ) induced epileptic seizure. Eight weeks old mice were used in the study. Animals were distributed in the following groups: Group I: Control group treated with PTZ, Group II: 15min cellular phone radiation+PTZ treatment+30min cellular phone radiation, Group III: 30min cellular phone radiation+PTZ treatment+30min cellular phone radiation. The RF radiation was produced by a 900MHz cellular phone. Lipid peroxidation, which is the indicator of oxidative stress was quantified by measuring the formation of thiobarbituric acid reactive substances (TBARS). The glutathione (GSH) levels were determined by the Ellman method. Tissue total nitric oxide (NOx) levels were obtained using the Griess assay. Lipid peroxidation and NOx levels of brain tissue increased significantly in group II and III compared to group I. On the contrary, GSH levels were significantly lower in group II and III than group I. However, no statistically significant alterations in any of the endpoints were noted between group II and Group III. Overall, the experimental findings demonstrated that cellular phone radiation may increase the oxidative damage and NOx level during epileptic activity in mouse brain., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Aims: Previous reports on the possible effects of Extremely Low Frequency Magnetic Fields (ELF MF) on mood have been paradoxical in different settings while no study has yet been conducted on animal behavior. In addition, it was shown that ELF MF exposure makes an increase in brain nitric oxide level. Therefore, in the current study, we aimed to assess the possible effect(s) of ELF MF exposure on mice Forced Swimming Test (FST) and evaluate the probable role of the increased level of nitric oxide in the observed behavior., Main Methods: Male adult mice NMRI were recruited to investigate the short term and long term ELF MF exposure (0.5 mT and 50 Hz, single 2h and 2 weeks 2h a day). Locomotor behavior was assessed by using open-field test (OFT) followed by FST to evaluate the immobility time. Accordingly, NΩ-nitro-l-arginine methyl ester 30 mg/kg was used to exert anti-depressant like effect., Key Findings: According to the results, short term exposure did not alter the immobility time, whereas long term exposure significantly reduces immobility time (p<0.01). However, it was revealed that the locomotion did not differ among all experimental groups. Short term exposure reversed the anti-depressant like effect resulting from 30 mg/kg of NΩ-nitro-l-arginine methyl ester (p<0.01)., Significance: It has been concluded that long term exposure could alter the depressive disorder in mice, whereas short term exposure has no significant effect. Also, reversing the anti-depressant activity of L-NAME indicates a probable increase in the brain nitric oxide., (Copyright © 2016 Elsevier Inc. All rights reserved.)

The applying of millimeter-wave electromagnetic emission (EHF-therapy) is an effective method for various age-related pathologies treatment, among other cardio-vascular diseases. During the EHF-emission of aging human endothelial cell cultures it was obtained changing of NO-synthase (eNOS), endothelin-1, angiotensin-2 and vasopressin expression dependence of irradiation exposition. These data have shown that EHF-emission has activated endothelium functional activity, which can play the important role to search for approaches to treatment of arterial hypertension and atherosclerosis.

Nitric oxide (NO) is a well-known free-radical molecule which is endogenously biosynthesised and shows various functions in mammals. To investigate NO functions, photocontrollable NO donors, compounds which release NO in response to light, are expected to be potentially useful. However, most of the conventional NO donors require harmful ultra-violet light for NO release. In this study, two dimethylnitrobenzene derivatives conjugated with coumarins were designed, synthesized and evaluated as photocontrollable NO donors. The optical properties and efficiency of photo-induced NO release were dependent upon the nature of the conjugation system. One of these compounds, Bhc-DNB (1), showed spatiotemporally well-controlled NO release in cultured cells upon exposure to light in the less-cytotoxic visible wavelength range (400-430 nm)., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Background: Low-level laser irradiation promotes cell viability and wound healing in periodontal tissue. However, its effect on periodontal pathogenic bacteria is unknown. The purpose of this study is to investigate the biologic effect of low-level laser irradiation on Porphyromonas gingivalis., Methods: A murine macrophage cell line (RAW 264.7) was cultured and treated with gallium-aluminum-arsenate (GaAlAs) laser-irradiated P. gingivalis with varying levels of energy fluency. Gene expression of monocyte chemotactic protein-1 (MCP-1), interleukin-6 (IL-6), interferon-β (IFN-β), and inducible nitric oxide synthase (iNOS) was examined by reverse transcription-polymerase chain reaction. Production of iNOS was determined by Western blot analysis, and nitric oxide (NO) release was assessed using Griess reagent. Flow cytometric analysis was performed to determine the activation of Toll-like receptors (TLRs) in response to P. gingivalis., Results: The laser-irradiated P. gingivalis significantly enhanced messenger RNA and protein levels of iNOS in RAW 264.7. Although the laser irradiation on P. gingivalis did not alter the expression level of MCP-1, IL-6, and IFN-β, it showed a noticeable effect on NO production in RAW 264.7. Furthermore, the laser-irradiated P. gingivalis accelerated TLR2 activation, but not TLR4 activation., Conclusions: This study reveals that GaAlAs laser irradiation on P. gingivalis induced iNOS expression at the transcriptional and translation levels and increased NO release in macrophages. Moreover, it is confirmed that this process was mediated specifically by TLR2 activation. These findings suggest that low-level laser irradiation to periodontal pathogenic bacteria could be detrimental to periodontal treatments.

We present a new photo-fragment imaging spectrometer, which employs a movable repeller in a single field imaging geometry. This innovation offers two principal advantages. First, the optimal fields for velocity mapping can easily be achieved even using a large molecular beam diameter (5 mm); the velocity resolution (better than 1%) is sufficient to easily resolve photo-electron recoil in (2 + 1) resonant enhanced multiphoton ionization of N2 photoproducts from N2O or from molecular beam cooled N2. Second, rapid changes between spatial imaging, velocity mapping, and slice imaging are straightforward. We demonstrate this technique's utility in a re-investigation of the photodissociation of N2O. Using a hot nozzle, we observe slice images that strongly depend on nozzle temperature. Our data indicate that in our hot nozzle expansion, only pure bending vibrations--(0, v2, 0)--are populated, as vibrational excitation in pure stretching or bend-stretch combination modes are quenched via collisional near-resonant V-V energy transfer to the nearly degenerate bending states. We derive vibrationally state resolved absolute absorption cross-sections for (0, v2 ≤ 7, 0). These results agree well with previous work at lower values of v2, both experimental and theoretical. The dissociation energy of N2O with respect to the O((1)D) + N2¹Σ(g)⁺ asymptote was determined to be 3.65 ± 0.02 eV.

Tumor hypoxia, which occurs mainly as a result of inadequate tissue perfusion in solid tumors, is a well-known challenge for successful radiotherapy. Recent evidence suggests that ionizing radiation (IR) upregulates nitric oxide (NO) production and that IR-induced NO has the potential to increase intratumoral circulation. However, the kinetics of NO production and the responsible isoforms for NO synthase in tumors exposed to IR remain unclear. In this study, we aimed to elucidate the mechanism by which IR stimulates NO production in tumors and the effect of IR-induced NO on tumor radiosensitivity. Hoechst33342 perfusion assay and electron spin resonance oxymetry showed that IR increased tissue perfusion and pO2 in tumor tissue. Immunohistochemical analysis using two different hypoxic probes showed that IR decreased hypoxic regions in tumors; treatment with a nitric oxide synthase (NOS) inhibitor, L-NAME, abrogated the effects of IR. Moreover, IR increased endothelial NOS (eNOS) activity without affecting its mRNA or protein expression levels in SCCVII-transplanted tumors. Tumor growth delay assay showed that L-NAME decreased the anti-tumor effect of fractionated radiation (10Gy×2). These results suggested that IR increased eNOS activity and subsequent tissue perfusion in tumors. Increases in intratumoral circulation simultaneously decreased tumor hypoxia. As a result, IR-induced NO increased tumor radiosensitivity. Our study provides a new insight into the NO-dependent mechanism for efficient fractionated radiotherapy., (Copyright © 2013 Elsevier Inc. All rights reserved.)

Multi-photon excitation allows one to use tissue transmitting near-infrared (NIR) light to access excited states with energies corresponding to single-photon excitation in the visible or ultraviolet wavelength ranges. Here, we present an overview of the application of both simultaneous and sequential multi-photon excitation in studies directed towards the photochemical delivery ('uncaging') of bioactive small molecules such as nitric oxide (NO) to physiological targets. Particular focus will be directed towards the use of dyes with high two-photon absorption cross sections and lanthanide ion-doped upconverting nanoparticles as sensitizers to facilitate the uncaging of NO using NIR excitation.

Despite their high physiological relevance, haemoglobin crystal structures with NO bound to haem constitute less than 1% of the total ligated haemoglobins (Hbs) deposited in the Protein Data Bank. The major difficulty in obtaining NO-ligated Hbs is most likely to be related to the oxidative denitrosylation caused by the high reactivity of the nitrosylated species with O(2). Here, using Raman-assisted X-ray crystallography, it is shown that under X-ray exposure (at four different radiation doses) crystals of nitrosylated haemoglobin from Trematomus bernacchii undergo a transition, mainly in the β chains, that generates a pentacoordinate species owing to photodissociation of the Fe-NO bond. These data provide a physical explanation for the low number of nitrosylated Hb structures available in the literature.

Introduction: Ultraviolet B (UVB, 290 nm to 320 nm) has been reported to modulate the cytokine-mediated inflammatory process in various inflammatory skin conditions, including production of TNF-α, IL-1α, IL-6, IL-8, and IL-10. We constructed an in vitro model system involving co-culture of different cell types to study the effect of UVB on the inflammatory process using nitric oxide (NO) and tumor necrosis factor (TNF)-α as markers of inflammation., Objective: This study was conducted to quantitatively assess the products secreted by human epithelial keratinocytes in the presence and absence of macrophages/monocytes., Methods: Cells were exposed to UVB radiation (50 mJ to 200 mJ per cm2) or treated with bacterial lipopolysaccharide (LPS) as stimulator of inflammatory response. Nitric oxide (NO) was measured by modified Griess assay and TNF-α was measured by quantitative ELISA. For the co-culture system, SC monocytes were seeded in a 24-well Transwell tissue culture plate whereas irradiated keratinocytes were seeded in the individual baskets subsequently placed on top of the monocyte cultures, and samples of culture supernatants were collected at 1 to 6 days., Results: When primary human epidermal keratinocytes (NHEK) were irradiated with UVB, a dose-dependent stimulation of TNF-α production was observed (33% to 200% increase). TNF-α production was not changed significantly in SC monocytes/NHEK co-culture. In contrast, when macrophages were irradiated with UVB, significant inhibition of NO production (40% suppression, P<0.001) was seen., Conclusion: This improved model of cutaneous inflammation could use multiple cells to study their interactions and to offer convenience, reproducibility, and a closer approximation of in vivo conditions.

The development of the bystander effect induced by low doses of irradiation in human umbilical vein endothelial cells (HUVECs) depends on extracellular DNA (ecDNA) signaling pathway. We found that the changes in the levels of ROS and NO production by human endothelial cells are components of the radiation induced bystander effect that can be registered at a low dose. We exposed HUVECs to X-ray radiation and studied effects of ecDNA(R) isolated from the culture media conditioned by the short-term incubation of irradiated cells on intact HUVECs. Effects of ecDNA(R) produced by irradiated cells on ROS and NO production in non-irradiated HUVECs are similar to bystander effect. These effects at least partially depend on TLR9 signaling. We compared the production of the nitric oxide and the ROS in human endothelial cells that were (1) irradiated at a low dose; (2) exposed to the ecDNA(R) extracted from the media conditioned by irradiated cells; and (3) exposed to human DNA oxidized in vitro. We found that the cellular responses to all three stimuli described above are essentially similar. We conclude that irradiation-related oxidation of the ecDNA is an important component of the ecDNA-mediated bystander effect., (Copyright © 2011 Elsevier B.V. All rights reserved.)

The circadian rhythms of background gamma-radiation and Ki-indexes of geomagnetic activity (GMF) during August-September 2008, January-February 2010 and March 2011 were studied. The authors show that in summer period the maximum of Ki-indexes and gamma-radiation were at 3 p.m. of local time. In winter these maximums were shifted at more last time. It was suggested that an organism produces the own free radicals as nitric oxide to neutralize radicals from background radiation. They are formed during decay of neutrophiles when GMF-activity falls. On the other side, the production of NO is regulated by melatonin synthesis which has a circadian rhythm.

Purpose: Nitric oxide (NO), a reactive radical, is formed in higher amounts from L-arginine by inducible NO synthase (iNOS) during early response to ionizing radiation presumably as a part of signal transduction pathways. This study investigated the changes in L-arginine-NO metabolic pathways within a 24-hour period after whole-body gamma irradiation of rats with the range of low to supra-lethal doses., Materials and Methods: Young adult female Wistar rats received either 0-50 Gy whole-body irradiation or an intraperitoneal injection of bacterial lipopolysaccharide (LPS, 10 mg/kg). Exhaled NO was monitored using chemiluminiscence, nitrite + nitrate (NO(x)) and L-arginine were assayed by high-performance liquid chromatography, and expression of iNOS was determined using Western blot., Results: Irradiation resulted in a dose-dependent increase of plasma NO(x) to maximum levels which were 4-fold higher compared to controls (p < 0.001). The NO(x) levels increased less in the bronchoalveolar lavage fluid (BAL) (1.7-fold, p < 0.001) and liver homogenate (2.5-fold, p < 0.05), respectively, and were dose-independent. Exhaled NO, lung NO(x), plasma and BAL L-arginine, and the expression of iNOS in lung and liver tissues of irradiated rats and controls were similar. LPS caused a considerable increase (p < 0.001) in exhaled NO (61-fold), NO(x) levels (plasma 34-fold, BAL 6-fold, lung 5-fold, liver 4-fold), and in iNOS expression, respectively., Conclusion: In contrast to the LPS treatment of rats, the radiation-induced changes in L-arginine-NO metabolic pathways are modest, particularly in the airways and lungs. Noninvasive measurement of exhaled NO within a 24-h period following the exposure of rats to ionizing radiation has no value for biodosimetry.

In this study, we demonstrate that aerosol assisted flow synthesized B, N-codoped TiO(2) photocatalyst possesses superior photocatalytic activity to pure and single element doped counterparts on the degradation of NO in a flow system under both simulated solar light and visible light irradiation. Characterization results revealed that B, N-codoped TiO(2) photocatalyst was composed of hollow microspheres. Boron and nitrogen were in the form of Ti-O-B and N-Ti-O structures, respectively. The introduction of B and N into the TiO(2) lattice could effectively tune the band gap of TiO(2) and extend its optical response to the visible-light region. The synergistic effect of B and N codoping on visible light driven photocatalytic activity enhancement of TiO(2) was discussed on the basis of experimental results., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Oxidative stress may affect many cellular and physiological processes including gene expression, cell growth, and cell death. In the recent study, we aimed to investigate whether 900 MHz pulse-modulated radiofrequency (RF) fields induce oxidative damage on lung, heart and liver tissues. We assessed oxidative damage by investigating lipid peroxidation (malondialdehyde, MDA), nitric oxide (NOx) and glutathione (GSH) levels which are the indicators of tissue toxicity. A total of 30 male Wistar albino rats were used in this study. Rats were divided randomly into three groups; control group (n = 10), sham group (device off, n = 10) and 900 MHz pulsed-modulated RF radiation group (n = 10). The RF rats were exposed to 900 MHz pulsed modulated RF radiation at a specific absorption rate (SAR) level of 1.20 W/kg 20 min/day for three weeks. MDA and NOx levels were increased significantly in liver, lung, testis and heart tissues of the exposed group compared to sham and control groups (p < 0.05). Conversely GSH levels were significantly lower in exposed rat tissues (p < 0.05). No significantly difference was observed between sham and control groups. Results of our study showed that pulse-modulated RF radiation causes oxidative injury in liver, lung, testis and heart tissues mediated by lipid peroxidation, increased level of NOx and suppression of antioxidant defense mechanism.

A chemical absorption-biological reduction integrated process has been proposed for the removal of nitrogen oxides (NO(x)) from flue gases. In this study, we report a new approach using biofilm electrode reactor (BER) to regenerate Fe(II)EDTA via simultaneously reducing Fe(II)EDTA-NO and Fe(III)EDTA in NO(x) scrubber solution. Biofilm formed on the surface of the cathode was confirmed by Environmental Scan Electro-Microscope. Experimental results demonstrated that it was effective and feasible to utilize the BER to promote the reduction of Fe(II)EDTA-NO and Fe(III)EDTA simultaneously. The reduction efficiency of Fe(II)EDTA-NO and Fe(III)EDTA was up to 85% and 78%, respectively when the BER was continuously operated with electricity current at 30 mA. The absence of electricity induced an immediate decrease in reduction efficiency, indicating that the bio-regeneration of ferrous chelate complex was electrochemically accelerated. The present approach is considered advantageous for the enhanced bio-reduction in the NO(x) scrubber solution., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Lymphocytes are more sensitive to radiation in vivo than in vitro. However, the mechanism of this differential response is poorly understood. In the present study, it was found that the lipid peroxidation and cell death were significantly higher in lymphocytes following whole body irradiation (WBI) as compared to lymphocytes exposed to radiation in vitro. EL-4 cells transplanted in mice were also more sensitive to radiation than EL-4 cells irradiated in vitro. DNA repair, as assessed by comet assay, was significantly faster in lymphocytes exposed to 4Gy radiation in vitro as compared to that in lymphocytes obtained from whole body irradiated mice exposed to the same dose of radiation. This was associated with increased NF-κB activation in response to genotoxic stress and lesser activation of caspase in lymphocytes in vitro compared to in vivo. To explain the differential radiosensitivity, we postulated a role of nitric oxide, an extrinsic diffusible mediator of radiosensitivity that has also been implicated in DNA repair inhibition. Nitric oxide levels were significantly elevated in the plasma of whole body irradiated mice but not in the supernatant of cells irradiated in vitro. Addition of sodium nitroprusside (SNP), a nitric oxide donor to cells irradiated in vitro inhibited the repair of DNA damage and enhanced apoptosis (increased Bax to Bcl-2 ratio). Administration of l-NAME, a nitric oxide synthase inhibitor, to mice significantly protected lymphocytes against WBI-induced DNA damage and inhibited in vivo radiation-induced production of nitric oxide. These results confirm that the observed differential radiosensitivity of lymphocytes was due to slow repair of DNA due to nitric oxide production in vivo., (2010 Elsevier B.V. All rights reserved.)

Cranial irradiation remains a frontline treatment for brain cancer, but also leads to normal tissue damage. Although low-dose irradiation (≤10 Gy) causes minimal histopathologic change, it can elicit variable degrees of cognitive dysfunction that are associated with the depletion of neural stem cells. To decipher the mechanisms underlying radiation-induced stem cell dysfunction, human neural stem cells (hNSCs) subjected to clinically relevant irradiation (0-5 Gy) were analyzed for survival parameters, cell-cycle alterations, DNA damage and repair, and oxidative stress. hNSCs showed a marked sensitivity to low-dose irradiation that was in part due to elevated apoptosis and the inhibition of cell-cycle progression that manifested as a G2/M checkpoint delay. Efficient removal of DNA double-strand breaks was indicated by the disappearance of γ-H2AX nuclear foci. A dose-responsive and persistent increase in oxidative and nitrosative stress was found in irradiated hNSCs, possibly the result of a higher metabolic activity in the fraction of surviving cells. These data highlight the marked sensitivity of hNSCs to low-dose irradiation and suggest that long-lasting perturbations in the CNS microenvironment due to radiation-induced oxidative stress can compromise the functionality of neural stem cells., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Elevation of nitric oxide (NO*) can either promote or inhibit ultraviolet B light (UVB)-induced apoptosis. In this study, we determined real-time concentration of NO* and peroxynitrite (ONOO(-)) and their role in regulation of membrane integrity and apoptosis. Nanosensors (diameter 300-500 nm) were used for direct in situ simultaneous measurements of NO* and ONOO(-) generated by UVB in cultured keratinocytes and mice epidermis. An exposure of keratinocytes to UVB immediately generated ONOO(-) at maximal concentration of 190 nm followed by NO(*) release with a maximal concentration of 91 nm. The kinetics of UVB-induced NO*/ONOO(-) was in contrast to cNOS agonist stimulated NO*/ONOO(-) from keratinocytes. After stimulating cNOS by calcium ionophore (CaI), NO* release from keratinocytes was followed by ONOO(-) production. The [NO*] to [ONOO(-)] ratio generated by UVB decreased below 0.5 indicating a serious imbalance between cytoprotective NO* and cytotoxic ONOO(-)-a main component of nitroxidative stress. The NO*/ONOO(-) imbalance increased membrane damage and cell apoptosis was partially reversed in the presence of free radical scavenger. The results suggest that UVB-induced and cNOS-produced NO* is rapidly scavenged by photolytically and enzymatically generated superoxide (O(2) (-)) to produce high levels of ONOO(-), which enhances oxidative injury and apoptosis of the irradiated cells.

Between age diseases two are standing out: oncological and cardiovascular ones. They give a main contribution to mortality of the population. Those who avoid these diseases have a chance to live longer. The author suggests a hypothesis of one common factor, which deviation leads to oncology or cardiovascular illness. Such factor is a production of nitric oxide in the organism, which depends on the geomagnetic activity (GMA). At excess production of nitric oxide the risk of oncopathology (breast cancer, bladder and lung cancer and others) is increased. At low NO level in blood the risk of cardiovascular disease is increased. The ability of the organism to utilize the excess level of NO depends on GMA inside the womb period. The production of nitric oxide in the organism goes by different ways, including NO-synthase activity and destruction of neutrophiles, which depends on the GMA and sun activity.

A new approach to the simultaneous removal of SO2 and NO from flue gas, by TiO2 photocatalysis based on UV irradiation technology, is presented. Experiments on the simultaneous desulphurization and denitrification were carried out using this photocatalyst in a self-designed photocatalytic reactor. Under the optimal experimental conditions, a removal efficiency of 98% for SO2 and 50% for NO was achieved. Scanning electron microscopy, transmission electron microscopy and X-ray energy spectrometry were used to observe the surface characteristics of the TiO2 photocatalyst. It was found that the surface of the quartz sand carrier was covered with Ti, on which the Si content of the quartz sand carrier was similar to the Ti content, indicating that the quartz sand supported the TiO2 membrane well. Based on the results of X-ray photoelectron spectroscopy (XPS) and chemical analysis of the resulting products, the SO2 and NO removal mechanisms were revealed. Sulphate was the main desulphurization product and nitrite was the main denitrification product. In the removal reaction, NO was rapidly oxidized to NO2 and absorbed in the chemical reaction.

In this study, C-N-S-tridoped titanium dioxide (TiO(2)) nanocrystals were synthesized by using a facile hydrothermal method in the presence of a biomolecule l-cysteine. This biomolecule could not only serve as the common source for the carbon, sulfur and nitrogen tridoping, but also could control the final crystal phases and morphology. The resulting materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), nitrogen adsorption and UV-vis diffuse reflectance spectroscopy. XPS analysis revealed that S was incorporated into the lattice of TiO(2) through substituting oxygen atoms, N might coexist in the forms of N-Ti-O and Ti-O-N in tridoped TiO(2) and most C could form a mixed layer of carbonate species deposited on the surface of TiO(2) nanoparticles. The photocatalytic activities of the samples were tested on the removal of NO at typical indoor air level in a flow system under simulated solar light irradiation. The tridoped TiO(2) samples showed much higher removal efficiency than commercial P25 and the undoped counterpart photocatalyst. The enhanced visible light photocatalytic activity of C-N-S-tridoped TiO(2) nanocrystals was explained on the basis of characterizations. The possible formation process of the monodispersed C-N-S-tridoped anatase TiO(2) nanocrystals was also proposed. This study provides a new method to prepare visible light active TiO(2) photocatalyst.

Background: The bacterial endotoxin lipopolysaccharide (LPS) represents a prime pathogenic factor of peri-implantitis because of its ability to adhere tenaciously to dental titanium implants. Despite this, the current therapeutic approach to this disease remains based mainly on bacterial decontamination, paying little attention to the neutralization of bioactive bacterial products. The purpose of the present study was to evaluate whether irradiation with low-energy neodymium-doped:yttrium, aluminum, and garnet (Nd:YAG) laser, in addition to the effects on bacterial implant decontamination, was capable of attenuating the LPS-induced inflammatory response., Methods: RAW 264.7 macrophages or human umbilical vein endothelial cells were cultured on titanium disks coated with Porphyromonas gingivalis LPS, subjected or not to irradiation with the Nd:YAG laser, and examined for the production of inflammatory cytokines and the expression of morphologic and molecular markers of cell activation., Results: Laser irradiation of LPS-coated titanium disks significantly reduced LPS-induced nitric oxide production and cell activation by the macrophages and strongly attenuated intercellular adhesion molecule-1 and vascular cell adhesion molecule expression, as well as interleukin-8 production by the endothelial cells., Conclusion: By blunting the LPS-induced inflammatory response, Nd:YAG laser irradiation may be viewed as a promising tool for the therapeutic management of peri-implantitis.

The composite titanium dioxide (TiO(2)) films coating on the woven glass fabric were prepared by a modified sol-gel process, using pre-calcinated TiO(2) nanoparticle or silica gel as filler. The characterized physicochemical properties of the prepared catalyst films showed that the specific surface area, the microstructure and the crystal structure of the catalysts were greatly affected by the fillers and the calcination temperature. The physicochemical properties of composite films and the photocatalytic activity of nitric oxide (NO) show that the pre-calcinated TiO(2) nanoparticle is more favorable than silica gel as filler. The pre-calcinated TiO(2) nanoparticle filler can increase the photocatalytic activities of the catalysts by increasing the specific surface area, introducing a bimodal mesoporous structure, and creating a polymorphous crystal structure. And the TiO(2)-TiO(2) film calcinated at 400 degrees C exhibits the highest photocatalytic activity for NO oxidation and is more active than Degussa P25.

Pd-modified TiO(2) prepared by thermal impregnation method was used in this study for photocatalytic oxidation of NO in gas phase. The physico-chemical properties of Pd/TiO(2) catalysts were characterized by X-ray diffraction analysis (XRD), Brunauer-Emmett-Teller measurements (BET), X-ray photoelectron spectrum analysis (XPS), transmission electron microscopy (TEM), high resolution-transmission electron microscopy (HR-TEM), UV-vis diffuse reflectance spectra (UV-vis DRS) and photoluminescence spectra (PL). It was found that Pd dopant existed as PdO particles in as-prepared photocatalysts. The results of PL spectra indicated that the photogenerated electrons and holes were efficiently separated after Pd doping. During in situ XPS study, it was found that the content of hydroxyl groups on the surface of Pd/TiO(2) increased when the catalyst was irradiated by UV light, which could result in the improvement of photocatalytic activity. The activity test showed that the optimum Pd dopant content was 0.05 wt.%. And the maximum conversion of NO was about 72% higher than that of P25 when the initial concentration of NO was 200 ppm, which showed that Pd/TiO(2) photocatalysts could be potentially applied to oxidize higher concentration of NO.

Gas-phase photocatalytic oxidation (PCO) of nitric oxide (NO) with immobilized TiO2 films was studied in this paper. The immobilized TiO2 films were synthesized by hydrothermal method. The characterization for the physicochemical properties of catalysts prepared under different hydrothermal conditions were carried out by X-ray diffraction analysis (XRD), transmission electron microscopy (TEM), high resolution-transmission electron microscopy (HR-TEM), Brunauer-Emmett-Teller measurements (BET) and scanning electron micrograph (SEM). It was found that the PCO efficiency of the catalyst was mainly depended on the hydrothermal conditions. The optimal values of hydrothermal temperature and hydrothermal time were 200 degrees C and 24 h, respectively. Furthermore, it was also known that the photocatalytic efficiency would decrease remarkably when the calcination temperature was over than 450 degrees C. Under the optimal conditions (hydrothermal condition: 200 degrees C for 24 h; calcination temperature: 450 degrees C), the photocatalytic efficiency of catalyst could reach 60% higher than that of Degussa P25.

An organic tracer method, recently proposed for estimating individual contributions of toluene and alpha-pinene to secondary organic aerosol (SOA) formation, was evaluated by conducting a laboratory study where a binary hydrocarbon mixture, containing the anthropogenic aromatic hydrocarbon, toluene, and the biogenic monoterpene, alpha-pinene, was irradiated in air in the presence of NO(x) to form SOA. The contributions of toluene and alpha-pinene to the total SOA concentration, calculated using the organic tracer method, were compared with those obtained with a more direct 14C content method. In the study, SOA to SOC ratios of 2.07 +/- 0.08 and 1.41 +/- 0.04 were measured for toluene and (alpha-pinene SOA, respectively. The individual tracer-based SOA contributions of 156 microg m(-3) for toluene and 198 microg m(-)3 for alpha-pinene, which together accounted for 82% of the gravimetrically determined total SOA concentration, compared well with the 14C values of 182 and 230 microg m(-3) measured for the respective SOA precursors. While there are uncertainties associated with the organic tracer method, largely due to the chemical complexity of SOA forming chemical mechanisms, the results of this study suggest the organic tracer method may serve as a useful tool for determining whether a precursor hydrocarbon is a major SOA contributor.

This study was undertaken to test the effect of irradiation on the histopathology of the hypothalamus and cerebral cortex. In addition, the probable effects of radiotherapy on the activities of antioxidant enzymes and levels of nitric oxide (NO) in the plasma were investigated as well. The effects of melatonin treatment on radiotherapy-based central nervous system (CNS) damage were also studied. For this purpose, the rats were randomized into four groups. The first group was the control group (sham-exposed group), the second group received only melatonin, the third group was irradiated and the fourth group received both melatonin and irradiation. Plasma samples of rats were collected for measuring the activities of superoxide dismutase (SOD), catalase (CAT) and the levels of NO. 24 h after the interventions, tissue samples were obtained from the hypothalamus and the cerebral cortex for the light microscopic investigations. These tissues were mostly affected by radiation. The results indicated that the application of radiation significantly enhanced the levels of plasma SOD and NO. On the other hand, melatonin pretreatment prevented the decrease in plasma CAT activity induced by irradiation. It was found that the application of melatonin could significantly prevent the irradiation-induced damages. Light microscopic results revealed that the damage of the CNS by radiation was prevented by the application of melatonin.

NO/N(2)/O(2)/H(2)O mixtures are usually converted into HNO(3) and/or NO(2) using different discharge approaches. In this study, a radio-frequency discharge was successfully used to reduce NO mainly into N(2) at a low pressure (4kPa). The influences of experimental parameters, including carrier gas, inlet concentration of NO, O(2), steam, and applied power, are discussed. At least 95.7% of the total N atoms converted from NO into N(2). Other traces of byproducts were N(2)O and HNO(2), but neither HNO(3) nor NO(2) were detected. In addition, conversion of NO apparently increased with elevated applied power or decreased inlet concentration of O(2), reaching 92.8% and 74.2% for the NO/N(2)/O(2) (2%) and NO/N(2)/O(2) (6%)/H(2)O (10%) mixtures, respectively, at 120W. In addition, from the optical emission spectra, a large amount of N(2) (first positive band and second positive band) and NO (gamma system) were observed, and the important reactions for NO removal and N(2) formation are proposed.

Reactions of laser-ablated Cu atoms with CO and NO mixtures in solid argon and neon have been investigated using matrix-isolation infrared spectroscopy. Copper carbonyls and copper nitrosyls have been observed, whereas copper carbonyl nitrosyl complexes are absent from the present experiments. New products, (CuCO)2, [NO]Cu[NO], Cu2(mu2-NO), and Cu(NO)2Cu, have been formed in the copper experiments and characterized using infrared spectroscopy on the basis of the results of the isotopic shifts, mixed isotopic splitting patterns, stepwise annealing, the change of reagent concentration and laser energy, and comparison with theoretical predictions. Density functional theory calculations have been performed on these copper carbonyls and copper nitrosyls, which support the identification of these products from the matrix infrared spectrum. A plausible reaction mechanism has been proposed to account for the formation of copper carbonyls and copper nitrosyls. Similar matrix experiments with Ag and Au produce no new species.

In this paper, continuing previous work, we report on experiments carried out to investigate the removal of NO from simulated flue gas in nonthermal plasmas. The plasma-induced decomposition of small concentrations of NO in N2 used as the carrier gas and O2 and CH4 as minority components has been studied in a surface wave discharge induced with a surfatron launcher. The reaction products and efficiency have been monitored by mass spectrometry as a function of the composition of the mixture. NO is effectively decomposed into N2 and O2 even in the presence of O2, provided always that enough CH4 is also present in the mixture. Other majority products of the plasma reactions under these conditions are NH3, CO, and H2. In the absence of O2, decomposition of NO also occurs, although in that case HCN accompanies the other reaction products as a majority component. The plasma for the different reaction mixtures has been characterized by optical emission spectroscopy. Intermediate excited species of NO*, C*, CN*, NH*, and CH* have been monitored depending on the gas mixture. The type of species detected and their evolution with the gas composition are in agreement with the reaction products detected in each case. The observations by mass spectrometry and optical emission spectroscopy are in agreement with the kinetic reaction models available in literature for simple plasma reactions in simple reaction mixtures.

This study was carried out in order to determine nitric oxide (NO) production immediately after a 1.5 T magnetic field 30 min exposure to an experimental group, comprising 33 healthy young male volunteers aged 18-26 years old. In addition, a control group, comprising 30 healthy male volunteers aged 19-26 years old, was not exposed to the magnetic field and their NO levels were also measured. The experimental group was exposed using a magnetic resonance imaging (MRI) apparatus. Nitrite and nitrate concentrations were determined by UV-VIS spectrophotometer. The results, related to the parameters measured in this study, were analyzed by one-way ANOVA. Total nitrite concentration in post-magnetic field samples was found to be higher than in pre-magnetic field samples (P < .05).

Obesity has been implicated in several diseases, including cancer; however, the relationship of obesity and susceptibility to ultraviolet (UV) radiation-caused skin diseases has not been investigated. As UV-induced oxidative stress has been implicated in several skin diseases, we assessed the role of obesity on UVB-induced oxidative stress in genetically obese Lep(ob)/Lep(ob) (leptin-deficient) mice. Here, we report that chronic exposure to UVB (120 mJ/cm(2)) resulted in greater oxidative stress in the skin of obese mice in terms of higher levels of H(2)O(2) and NO production, photo-oxidative damage of lipids and proteins, and greater depletion of antioxidant defense enzymes, like glutathione, glutathione peroxidase, and catalase. As UV-induced oxidative stress mediates activation of MAPK and NF-kappaB signaling pathways, we determined the effects of UVB on these pathways in obese mice. Exposure of obese mice to UVB resulted in phosphorylation of ERK1/2, JNK, and p38 proteins of the MAPK family. Compared to wild-type mice, the obese mice exhibited higher levels of phosphorylation of these proteins, greater activation of NF-kappaB/p65, and higher levels of circulating proinflammatory cytokines, including TNF-alpha, IL-1beta and IL-6, on UVB irradiation. Taking these results together, our study suggests for the first time that obesity in mice is associated with greater susceptibility to UVB-induced oxidative stress and therefore may be a risk factor for skin diseases associated with UVB-induced oxidative stress.

Hydroxyl radical (.OH)-initiated photooxidation reaction of toluene was carried out in a self-made smog chamber. Four individual seed aerosols such as ammonium sulfate, ammonium nitrate, sodium silicate and calcium chloride, were introduced into the chamber to assess their influence on the growth of secondary organic aerosols (SOA). It was found that the low concentration of seed aerosols might lead to high concentration of SOA particles. Seed aerosols would promote rates of SOA formation at the start of the reaction and inhibit its formation rate with prolonging the reaction time. In the case of ca. 9000 pt/cm3 seed aerosol load, the addition of sodium silicate induced a same effect on the SOA formation as ammonium nitrate. The influence of the four individual seed aerosols on the generation of SOA decreased in the order of calcium chloride>sodium silicate and ammonium nitrate>ammonium sulfate.

Nitric oxide (NO) is recognized as one of the major players in various biochemical processes, including blood pressure, neurotransmission and immune responses. However, experimental studies involving NO are often limited by difficulties associated with the use of NO gas, including its toxicity and precise control over NO concentration. Moreover, the reactions of NO with biological molecules, which frequently occur on time scales of microseconds or faster, are limited by the millisecond time scale of conventional stopped-flow techniques. Here we present a new approach for studying rapid biological reactions involving NO. The method is based on designed ruthenium and manganese nitrosyls, [Ru(PaPy3)(NO)](BF4)2 and [Mn(PaPy3)(NO)](ClO4) (PaPy3H = N,N-bis(2-pyridylmethyl)amine-N-ethyl-2-pyridine-2-carboxamide), which upon photolysis produce NO on a fast time scale. The kinetics of the binding of the photogenerated NO to reduced cytochrome c oxidase (CcO) and myoglobin (Mb) was investigated using time-resolved optical absorption spectroscopy. The NO was found to bind to reduced CcO with an apparent lifetime of 77 micros using the [Mn(PaPy3)(NO)]+ complex; the corresponding rate is 10-20 times faster than can be detected by conventional stopped-flow methods. Second-order rate constants of approximately 1 x 10(8) M(-1) s(-1) and approximately 3 x 10(7) M(-1) s(-1) were determined for NO binding to reduced CcO and Mb, respectively. The generation of NO by photolysis of these complexes circumvents the rate limitation of stopped-flow techniques and offers a novel alternative to study other fast biological reactions involving NO.

Time-resolved photoion and photoelectron velocity mapped images from NO(2) excited close to its first dissociation limit [to NO(X(2)Pi) + O((3)P(2))] have been recorded in a two colour pump-probe experiment, using the frequency-doubled and frequency-tripled output of a regeneratively amplified titanium-sapphire laser. At least three processes are responsible for the observed transient signals; a negative pump-probe signal (corresponding to a 266 nm pump), a very short-lived transient close to the cross-correlation of the pump and probe pulses but on the 400 nm pump side, and a longer-lived positive pump-probe signal that exhibits a signature of wavepacket motion (oscillations). These transients have two main origins; multiphoton excitation of the Rydberg states of NO(2) by both 266 and 400 nm light, and electronic relaxation in the 1(2)B(2) state of NO(2), which leads to a quasi-dissociated NO(2) high in the 1(2)A(1) electronic ground state and just below the dissociation threshold. The wavepacket motion that we observe is ascribed to states exhibiting free rotation of the O atom about the NO moiety. These states, which are common for loosely bound systems such as a van der Waals complex but unusual for a chemically-bound molecule, have previously been observed in the frequency domain by optical double resonance spectroscopy but never before in the time domain.

Therapeutic effects of lasers are based on activation of oxidative process on cellular and subcellular levels. The first photoacceptor of laser beam being mitochondria., which simultaneously represents the source of oxidation products as well as their target and thus, laser exposure can cause numerical effects: inactivation of electron chain components of mitochondria, energy metabolism inhibition, oxidation of lipids and DNA molecule. The aim of the given work is to investigate the influence of submaximal dozes of infrared (0,85 mkm) low-intensity laser on the activity of oxidative processes in laboratory mice blood, which are reflected on the state of paramagnetic centers. For this purpose the condition of blood paramagnetic centers (caeruloplazmin, Fe(3+)-transferin, Fe(2+), Mn(2+), MetHb and NO) has been studied. Results imply that irradiation of mice blood with submaximal dozes of low-intensity laser causes the activation of oxidative process, but those changes do not lead to impairment of blood antioxidant features.

Background/purpose: Because of large interest in biological effects of laser radiation used in laser therapy, the effect of extremely low-level red laser light intensity on the immune cell activity has been studied in the animal model with well-characterized macrophage and T cell populations as responder cells producing cytokines, protective proteins, active oxygen, and nitric compounds. To study of the possible side effects of laser immunotherapy we monitored the productions of cytokines, nitric oxide (NO), and heat shock protein 70 (Hsp70) in mice subjected to a periodic laser exposure for 1 month., Methods: Helium-neon laser radiation with the power of 0.2 mW/cm2 and wavelength of 632.8 nm was applied on two different mouse skin surfaces, i.e. a thymus projection area or a hind limb. Healthy NMRI male mice were irradiated repeatedly with laser light for 1 min with 48-h intervals for 30 days. The animals were divided into three groups of 25 mice. The first and the second groups were exposed to laser light, on the thymus and hind limb area, respectively. The third, sham-irradiated group served as a control. Early and prolonged effects of laser radiation on the levels of NO (by Griess assay), Hsp70 (by Western blot assay), tumor necrosis factors (TNF-alpha and TNF-beta) (by cytotoxic assay using L929 cells as targets), and interleukin-2 (IL-2) (by ELISA assay) were determined., Results: The dynamics of immune responses to low-power laser light intensity was shown to be dependent on two factors, i.e. the cumulative dose and the localization of the irradiated surface. Besides, various populations of cells demonstrated different sensitivity to laser radiation, with T cells being more responsive among examined populations of the cells. Low intensity laser light induced an immune cell activity when the exposure duration did not exceed 10 days, while a more prolonged period of treatment generated more severe changes in the immune system, up to immunosuppression. The treatment of the thymus zone resulted in more pronounced changes in the cytokine production as well as in NO and Hsp70 synthesis., Conclusion: Low-power laser irradiation showed more effective immunomodulatory effects when applied on the thymus projection area. The rise in IL-2 and Hsp70 production related to a short-term effect of laser application may be reversed after repeating laser treatment. We suggest that for the support of immune system stability, the prolonged laser therapy should be accompanied by supplementary methods.