Post-irradiation Changes Research Articles

Early and Late Effects of Low-Dose X-ray Exposure in Human Fibroblasts: DNA Repair Foci, Proliferation, Autophagy, and Senescence.

The effects of low-dose radiation exposure remain a controversial topic in radiation biology. This study compares early (0.5, 4, 24, 48, and 72 h) and late (5, 10, and 15 cell passages) post-irradiation changes in γH2AX, 53BP1, pATM, and p-p53 (Ser-15) foci, proliferation, autophagy, and senescence in primary fibroblasts exposed to 100 and 2000 mGy X-ray radiation. The results show that exposure to 100 mGy significantly increased γH2AX, 53BP1, and pATM foci only at 0.5 and 4 h post irradiation. There were no changes in p-p53 (Ser-15) foci, proliferation, autophagy, or senescence up to 15 passages post irradiation at the low dose.

Effects of physical sterilization on microbial safety, nutritional composition, and antioxidant activity of queen bee larva powder, a by-product of royal jelly production

Queen bee larvae (QBL), a by-product of royal jelly production, have nutritional value and confer health benefits. The commercialization of QBL is hindered because of the lack of evidence for its nutrition and safety parameters. Thus, this study was conducted to investigate the microbial dynamics, nutritional composition, and antioxidant activity of QBL, aiming to assess its potential as a food product. Lyophilized QBL powder samples were sterilized through gamma irradiation and high-pressure processing at varying doses and pressures. Gamma irradiation at 10 and 15 kGy effectively reduced the total aerobic count to 0, whereas high-pressure processing led to no significant reduction. Regarding the microbial profile of QBL, 16S rDNA gene sequencing unveiled five bacteria—Acinetobacter pittii, Bacillus thuringiensis, Enterococcus mundtii, Enterococcus faecalis, and Fructobacillus fructosus—but no major foodborne pathogens. Lactobacillus, Bombella, and Fructobacillus emerged as the predominant genera in QBL, with low abundances of Staphylococcus and Escherichia. Proximate composition analysis indicated no significant postirradiation changes in macronutrient contents; notably, protein was the predominant component (approximately 48.0%). Sugar and amino acid analyses revealed essential nutrients meeting human dietary requirements. Upon fatty acid analysis, palmitic and oleic acids emerged as predominant fatty acids. Gamma irradiation at 10 kGy exerted no significant effect on the nutritional composition or antioxidant activity of QBL. Our study provides valuable insights into the microbial safety and nutritional value of QBL, indicating its potential as a dietary protein source with favorable microbiota.

P06.16.A FRACTIONATED IRRADIATION ACTIVATES GLIOMA IMMUNE MICROENVIRONMENT AND BOOSTS ANTIGEN-SPECIFIC T CELL RESPONSE IN MALIGNANT GLIOMAS

Abstract Several ongoing clinical trials employ vaccine, immune checkpoint inhibitors and/or adoptive T cell therapy to treat glioblastoma. However, the impact of irradiation as part of the standard of care on the immune microenvironment and response to immunotherapy is ill-defined. In the present study, we analyzed the post-irradiation changes in the GBM immune microenvironment, and further elucidated the impact of fractionated tumor irradiation (FIR) on the efficacy of T cell-mediated immunotherapies in experimental gliomas. FIR boosted the response of orthotopically-implanted GL261 tumors expressing the tumor-associated antigen glycoprotein (gp)100 to a gp100 vaccine. Furthermore, FIR enhanced the infiltration of GL261-gp100 gliomas by adoptively-transferred gp100 T cell receptor-transgenic T cells, which also displayed a more activated and less exhausted phenotype post-irradiation. Single cell transcriptomic studies of tumor-infiltrating CD45+ leukocytes revealed that FIR promotes the expression of leukocyte-endothelial adhesion molecules in T cells, and transcripts encoding proinflammatory M1-like genes in tumor-associated microglia and macrophages. Collectively, our preclinical findings support the use of FIR with to increase response to T cell-based immunotherapies.

Thermal diffusivity variation assessment on Radio-Frequency Quadrupole Cu-OF copper due to proton irradiation

Particle accelerator components are exposed to high radiation environments that could lead to material property degradation and affect component’s performance and lifetime. The ability to deploy rapid, multi-modal, non-destructive techniques provides valuable insight in microstructure evolution of radiation induced effects. The current work demonstrates the use of Transient Grating Spectroscopy (TGS) as a powerful technique to detect post irradiation changes in thermal diffusivity of polycrystal, high-purity, oxygen-free copper (Cu-OF) used in Radio-Frequency Quadrupoles (RFQs). For that purpose, the nominal operation proton beam losses of the European Spallation source (ESS) RFQ were studied to define copper sample irradiation patterns at MIT Tandetron accelerator that emulate the radiation damage conditions corresponding to 24 h of operation. Sample measurements with TGS before and after irradiation were performed in order to assess potential variation in copper thermal properties. Irradiated samples with energy of 120 keV, incident angles of 0°, 40° and fluence of 1017 p/cm2 at room temperature and resulted damage of 0.015 dpa presented a decrease in their thermal diffusivity which can be attributed to point defect generation and void formation.

A method for time-independent film dosimetry: Can we obtain accurate patient-specific QA results at any time postirradiation?

AimThe aim of this work was twofold. (1) To investigate and present a comparison between EBT3 and EBT‐XD in terms of postirradiation color changes. (2) Create an automated workflow to allow radiochromic film (EBT3/XD) to be scanned and converted to dose accurately at any postirradiation time.Materials and MethodsTen GafChromic EBT‐XD calibration films were exposed in 2 Gy increments up to 18 Gy. Calibrates were then scanned at 5‐min intervals postirradiation over 24 h using an AutoHotKey script, resulting in 288 TIFF images. Following the 24‐h scanning period, a MATLAB script was used to automatically read the tiff images and create a series of 288 calibration curves distinct in time which is termed as the “Temporal Calibration Model” (TCM). The model is saved as a series of polynomial fit coefficients to net optical density as a function of dose, timestamped in 5‐min increments. Ten patient‐specific film measurements (5 × EBT‐XD and 5 × EBT3) were then carried out and scanned using the same 5‐min scan intervals from 5 min postirradiation to 24 h postirradiation. The TCM was then automatically applied using eFilmQA software to convert the patient‐specific QA films to dose by applying the relevant calibration curve from the TCM, corresponding to the arbitrary postirradiation time that the film was scanned. Each dose plane at postirradiation scan intervals of 5 min up to 20 h was then compared to the ground‐truth dose plane using gamma analysis.ResultsGamma pass rates using the TCM at time t, normalized to the pass rate after 20 h postirradiation, were found to have a maximum coefficient of variation of 3% over any postirradiation time. Conversely, not using the TCM resulted in coefficients of variation of up to 39%. Clinical implementation of this method showed an average accuracy of 2.8% when comparing the clinical result to the TCM result.ConclusionsWe have developed a methodology that allows radiochromic film to be accurately used as a dosimeter at any arbitrary scan postirradiation time, whereas previously, waiting periods of 16–24 h before readout were needed to ensure the postirradiation changes had stabilized. The creation of a TCM can enable results from radiochromic film measurements to be obtained quickly postirradiation. Using a conventional single calibration curve generated at 20 h postirradiation can result in gamma pass‐rate difference of up to 75% for measurement films scanned at a much shorter postirradiation time.

Influence of irradiation with accelerated electrons on the physical properties of polyethylene terephthalate

The influence of irradiation with accelerated electrons (energy 8.5 MeV, dose 5 kGy) on the physical properties of medical devices made of polyethylene terephthalate (PET) was studied by infrared (IR) spectroscopy. The revealed post-irradiation changes in the IR spectra can be used to justify the choice of the dose of irradiation of PET products with electrons during the radiation sterilization procedure. Keywords: polyethylene terephthalate, irradiation with accelerated electrons.

LONG-TERM RADIATION-INDUCED EFFECTS ON SOLID STATE CHITOSAN

Treatment of chitosan with ionising radiation is one of the methods by which it is modified for various applications. However, in the case of chitosan irradiated in the solid state, the radicals formed during irradiation can be stabilised in its crystalline phase and subsequently cause post-irradiation changes. It has been observed that further degradation of the polymer occurs during storage of the irradiated polymer, resulting in an increase in oxidation products and a decrease in deacetylation degree. This effect results from the transformation of radicals leading to the formation of stable nitroxyl radicals, a process observed years after irradiation.

Optical properties degradation of wollastonite powders under the electron irradiation in vacuum

The study on grain size distribution, phase composition, diffuse-reflectance spectra (ρλ), and integral absorption coefficient has been provided. In addition, the properties of wollastonite powders were examined after the irradiation with 30 keV electrons with recording ρλ spectra before and after each irradiation period in vacuum at the irradiation site (in situ). High powder reflectance has been determined, which provides a small value of absorption coefficient (аs = 0.11). It has been shown that optical properties degradation is determined mainly by UV radiation absorbing defects, the most probable among them being anionic vacancies. ρλ spectra are modified to a smaller extent while irradiating in the visible spectrum. The powder under analysis exceeds titanium dioxide powders, which are widely used as pigments for dyes and spacecraft reflective coatings, by the value of initial optical properties and their post-irradiation changes.

Effect of absorbed dose on post-irradiation coloration and interpretation of polymerization reaction in the Gafchromic EBT3 film

The change in the optical density/transmittance obtained for dose delivered to EBT3 films by 15 MeV photon beam in the range 0.1–20 Gy as a function of the time elapsed between film irradiation and readout is analyzed. The polymerization chain reaction expected for monomer unit i.e., di-acetylene, in EBT3 film is predicted. These films are repeatedly scanned up to 104 h after irradiation by EPSON expression 11000XL flatbed scanner and analyzed by ImageJ software. At doses, ≤ 1 Gy, the average change in net transmittance over 104 hours, is 19.6% and for dose range between 1.5 Gy-7 Gy and 8 Gy–20 Gy, the values are 5.7% and 2.7%, respectively. During initial 24 hours, the increase in net transmittance for dose range 0.1 Gy–1 Gy, 1.5 Gy–5 Gy and 6 Gy–20 Gy are 0.5%–29.6% (mean 14.2%), 2.4%–6.8% (mean 3.6%) and 1.5% - 3.3% (mean 2.3%), respectively. The di-acetylene monomer in Gafchromic film undergoes addition at 1, 4 positions and polymerization reaction involves three different steps i.e., chain initiation, propagation and termination. At low absorbed doses i.e., ≤1 Gy, the chain termination step is prolonged and post-irradiation changes have attained a saturated value (plateau region within ±2%) for a considerably longer period (average 24 h) as compared to the film irradiated with higher doses. The Optical density (OD)/transmittance increases with elapsed time while its rate of change decreases with time and saturation in OD is a dose-dependent phenomenon. At high absorbed doses, the changes due to post-irradiation coloration will be least significant as the RCF saturates rapidly i.e. within 6 hours. It is necessary to scan EBT3 film after 24 h and 6 h of irradiation for doses ≤1 Gy and above 1 Gy, respectively.

Pediatric CNS imaging and long-term effects of irradiation in pediatric oncology patients.

The aim of this study was to evaluate post-irradiation changes in the central nervous system (CNS) detected using magnetic resonance (MR) imaging. Magnetic resonance images of 15 children with CNS tumors treated through whole-brain irradiation over 10years were reviewed retrospectively. Variables such as age at the time of irradiation, total radiation dose, treatment length, and time interval between irradiation and MR changes, were evaluated. All patients included in the study had imaging abnormalities of the CNS. Eight patients (53%) developed CNS abnormalities within a short period of time - only a few months after irradiation (mean 4.8months). Seven patients (47%) developed CNS abnormalities within a long time interval after treatment (mean 4.6years). In almost all patients, a T2 increase in supra- and infratentorial white matter was observed. Follow-up examinations showed nine patients (60%) with cerebellar atrophy. In this sample of pediatric patients who underwent whole-brain irradiation, the time receiving irradiation was not related to the severity of the MR changes. A correlation between the age of the child or the length of the radiotherapy and the extent of the changes could not be confirmed. However, we observed a trend towards stronger brain parenchymal degeneration with cystic changes in the younger age group of children in our sample. Older children who received irradiation seem to be more susceptible to vascular dysplasia with cavernous hemangiomas and microbleeding.

Pseudoprogression in a patient with relapsed medulloblastoma after intensive chemotherapy and craniospinal irradiation. A clinical observation and literature review

High-dose chemotherapy (HDCT) with autologous hemopoietic stem cell transplantation (auto-HSCT) is currently an integral part of a standard of care for younger medulloblastoma (MB) patients and MB patients with relapse. As HDCT regimens are characterized by neurotoxicity, it may add to the one of radiation therapy. Therefore, some patients may develop post-irradiation clinical symptoms and MRI changes characteristic for disease progression, pseudoprogression. We report on a case of a 16-year old patient with relapsed MB treated by standard chemotherapy with consequent HDCT and craniospinal irradiation with a boost to cranial fossa posterior. One month after the radiation therapy was finished she developed focal neurological symptoms. The MRI and PET scan have shown cerebellar changes characteristic for disease progression. However, the therаpy with corticosteroids and bevacizumab was able to resolve most clinical symptoms. The MRI scan have also shown evident positive dynamics. Therefore, the clinical course and imaging dynamics corresponded to pseudoprogression. The probability of pseudoprogression may be higher in patients with MB relapse receiving second irradiation and HDCT with auto-HSCT. As we often do not have a morphological proof of relapse, we have to distinguish between progressive disease and pseudoprogression by a complex of clinical course and imaging data.

Post-irradiation Changes and Complications of Nasopharyngeal Carcinoma: A Review of Imaging Features

Post-irradiation Changes and Complications of Nasopharyngeal Carcinoma: A Review of Imaging Features

Impact of Single Dose Photons and Carbon Ions on Perfusion and Vascular Permeability: A Dynamic Contrast-Enhanced MRI Pilot Study in the Anaplastic Rat Prostate Tumor R3327-AT1.

We collected initial quantitative information on the effects of high-dose carbon (12C) ions compared to photons on vascular damage in anaplastic rat prostate tumors, with the goal of elucidating differences in response to high-LET radiation, using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI). Syngeneic R3327-AT1 rat prostate tumors received a single dose of either 16 or 37 Gy 12C ions or 37 or 85 Gy 6 MV photons (iso-absorbed and iso-effective doses, respectively). The animals underwent DCE-MRI prior to, and on days 3, 7, 14 and 21 postirradiation. The extended Tofts model was used for pharmacokinetic analysis. At day 21, tumors were dissected and histologically examined. The results of this work showed the following: 1. 12C ions led to stronger vascular changes compared to photons, independent of dose; 2. Tumor growth was comparable for all radiation doses and modalities until day 21; 3. Nonirradiated, rapidly growing control tumors showed a decrease in all pharmacokinetic parameters (area under the curve, Ktrans, ve, vp) over time; 4. 12C-ion-irradiated tumors showed an earlier increase in area under the curve and Ktrans than photon-irradiated tumors; 5. 12C-ion irradiation resulted in more homogeneous parameter maps and histology compared to photons; and 6. 12C-ion irradiation led to an increased microvascular density and decreased proliferation activity in a largely dose-independent manner compared to photons. Postirradiation changes related to 12C ions and photons were detected using DCE-MRI, and correlated with histological parameters in an anaplastic experimental prostate tumor. In summary, this pilot study demonstrated that exposure to 12C ions increased the perfusion and/or permeability faster and led to larger changes in DCE-MRI parameters resulting in increased vessel density and presumably less hypoxia at the end of the observation period when compared to photons. Within this study no differences were found between curative and sub-curative doses in either modality.

Recognizing Radiation Therapy–related Complications in the Chest

Radiation therapy is one of the cornerstones for the treatment of thoracic malignancies. Although advances in radiation therapy technology have improved the delivery of radiation considerably, adverse effects are still common. Postirradiation changes affect the organ or tissue treated and the neighboring structures. Advances in external-beam radiation delivery techniques and how these techniques affect the expected thoracic radiation-induced changes are described. In addition, how to distinguish these expected changes from complications such as infection and radiation-induced malignancy, and identify treatment failure, that is, local tumor recurrence, is reviewed. ©RSNA, 2019.

Postirradiation changes of the microbiological quality, aflatoxin, capsinoids, volatile oils, and the color of red pepper powder

Red pepper powder from a local market was vacuum-packaged in aluminum foil bags, irradiated by a 60Co gamma irradiator at seven doses (0, 3, 6, 9, 12, 15, and 18 kGy) and stored at ambient temperature for 8 months. Postirradiation changes of the microbiological quality, aflatoxin B1, volatile oils, pungency, and the color of red pepper powder during different storage periods were investigated. The results showed that γ-irradiation could effectively decontaminate the red pepper powder, which reduced the content of the total aerobic bacteria by 6 logs when irradiated at 18 kGy, and the irradiation effectively reduced the fungal load but had no obvious effect on the content of aflatoxin B1. The 18 kGy irradiation did not change the color of sample and reduced the amount of terpenes by 3%. However, during the storage period, the terpene's content in the irradiated samples showed a lower reduction compared with the control. Practical applications The study showed that irradiation had an obvious bactericidal effect, and a dose of 18 KGy could effectively decontaminate the spices, which made the microbiological quality achieve the national hygienic standard of irradiation spices. Gamma irradiation had no significant effect on the terpenes of red pepper powder, which were the main constituent of the volatiles. During storage, the pungency decreased a lot, but could be well preserved by aluminum foil bag. This study could provide some reference for the setting of irradiation dose and the detection of higher-dose irradiated spices, and provide a new way for the storage of red pepper powder.

In vitro investigation of head and neck cancer stem cell proportions and their changes following X-ray irradiation as a function of HPV status.

IntroductionSome head and neck squamous cell carcinomas (HNSCC) have a distinct aetiology, which depends on the presence of oncogenic human papilloma virus (HPV). Also, HNSCC contains cancer stem cells (CSCs) that have greater radioresistance and capacity to change replication dynamics in response to irradiation compared to non-clonogenic cells. Since there is limited data on CSCs in HNSCC as a function of HPV status, better understanding of their radiobiology may enable improved treatment outcome.MethodsBaseline and post-irradiation changes in CSC proportions were investigated by flow cytometry in a HPV-negative (UM-SCC-1) and a HPV-positive (UM-SCC-47) HNSCC cell line, using fluorescent staining with CD44/ALDH markers. CSC proportions in both irradiated and unirradiated cultures were compared for the two cell lines at various times post-irradiation. To assess repopulation of CSCs, untreated cultures were depleted of CD44+/ALDH+ cells and re-cultured for 3 weeks before flow cytometry analysis.ResultsCSC proportions in untreated cell lines were 0.57% (UM-SCC-1) and 2.87% (UM-SCC-47). Untreated cell lines depleted of CD44+/ALDH+ repopulated this phenotype to a mean of 0.15% (UM-SCC-1) and 6.76% (UM-SCC-47). All UM-SCC-47 generations showed elevated CSC proportions after irradiation, with the most significant increase at 2 days post-irradiation. The highest elevation in UM-SCC-1 CSCs was observed at 1 day post-irradiation in the 2nd generation and at 3 days after irradiation in the 3rd generation. When measured after 10 days, only the 3rd generation of UM-SCC-1 showed elevated CSCs.ConclusionsCSC proportions in both cell lines were elevated after exposure and varied with time post irradiation. UM-SCC-47 displayed significant plasticity in repopulating the CSC phenotype in depleted cultures, which was not seen in UM-SCC-1.

Identification of CEA-interacting proteins in colon cancer cells and their changes in expression after irradiation.

PurposeThe serum carcinoembryonic antigen (CEA) level has been recognized as a prognostic factor in colorectal cancer, and associated with response of rectal cancer to radiotherapy. This study aimed to identify CEA-interacting proteins in colon cancer cells and observe post-irradiation changes in their expression.Materials and MethodsCEA expression in colon cancer cells was examined by Western blot analysis. Using an anti-CEA antibody or IgG as a negative control, immunoprecipitation was performed in colon cancer cell lysates. CEA and IgG immunoprecipitates were used for liquid chromatography–tandem mass spectrometry (LC-MS/MS) analysis. Proteins identified in the CEA immunoprecipitates but not in the IgG immunoprecipitates were selected as CEA-interacting proteins. After radiation treatment, changes in expression of CEA-interacting proteins were monitored by Western blot analysis.ResultsCEA expression was higher in SNU-81 cells compared with LoVo cells. The membrane localization of CEA limited the immunoprecipitation results and thus the number of CEA-interacting proteins identified. Only the Ras-related protein Rab-6B and lysozyme C were identified as CEA-interacting proteins in LoVo and SNU-81 cells, respectively. Lysozyme C was detected only in SNU-81, and CEA expression was differently regulated in two cell lines; it was down-regulated in LoVo but up-regulated in SNU-81 in radiation dosage-dependent manner.ConclusionCEA-mediated radiation response appears to vary, depending on the characteristics of individual cancer cells. The lysozyme C and Rab subfamily proteins may play a role in the link between CEA and tumor response to radiation, although further studies are needed to clarify functional roles of the identified proteins.

MP24-16 UROSYMPHYSEAL FISTULATION - WHAT'S IN A NAME?

You have accessJournal of UrologyTrauma/Reconstruction/Diversion: Ureter (including Pyeloplasty) and Bladder Reconstruction (including fistula), Augmentation, Substitution, Diversion I1 Apr 2017MP24-16 UROSYMPHYSEAL FISTULATION - WHAT'S IN A NAME? Simon Bugeja, Stella Ivaz, Stacey Frost, Mariya Dragova, Daniela E Andrich, and Anthony R Mundy Simon BugejaSimon Bugeja More articles by this author , Stella IvazStella Ivaz More articles by this author , Stacey FrostStacey Frost More articles by this author , Mariya DragovaMariya Dragova More articles by this author , Daniela E AndrichDaniela E Andrich More articles by this author , and Anthony R MundyAnthony R Mundy More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2017.02.3310AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Urosymphyseal fistulation is a recently described condition which is also referred to in the literature as osteitis pubis or pubic osteomyelitis. The morbidity of this is considerable particularly the pain it generates, which is often uncontrollable and unbearable. The name of the condition reflects our understanding of the nature and cause of the problem and in view of the discrepancy in terminology we have assessed the clinical, biochemical, microbiological and histological evidence in our own group of patients to determine the nature of the condition. METHODS There were 37 patients treated in our centre in the last five years (2012 - 2016 inclusive). We have complete data in 27 of these. Blood studies, imaging and microbiological investigations were performed preoperatively; microbiology and histology specimens were taken at the time of surgery; and there was further imaging and blood studies postoperatively. RESULTS The only imaging investigation that was 100% reliable was MRI scanning. The white blood cell count was normal in 6 patients and the average elevation was to 12.3 x103/μL. The CRP was elevated in every patient up to a level of a mean of 26.5mg/L. There appeared to be no specific correlation between the CRP and the symptoms. Urine culture was positive in only 12 patients (44.4%) with an even spread between coliforms, pseudomonas spp. and candida spp. The tissue culture was positive in 11 (40.7%) of the patients and did not necessarily match the urine culture. Histological assessment showed chronic inflammation in both the symphysis and the adjacent bone in 9 patients. There were external beam radiotherapy-related changes in all of these. There were chronic inflammatory changes in the symphysis alone in 18 patients. There was no evidence of osteomyelitis in any patient. CONCLUSIONS Essentially the characteristic intraoperative finding was of a thick-walled fluid containing cavity within the pubic symphysis which was sometimes related to inflammatory changes in the surrounding bone and sometimes to post-irradiation changes in the bone but never to any acute inflammatory change. Correlating the symptoms, the clinical findings, the surgical findings and the haematological and microbiological findings suggest that the fundamental problem is the urine leak and direct fistulation into (and sometimes through) the pubic symphysis. The more extensive the leak the worse the pain. The urinary and tissue microbiology did not correlate with each other or with the symptoms. The correct terminology for this condition, we believe, is Urosymphyseal Fistulae. © 2017FiguresReferencesRelatedDetails Volume 197Issue 4SApril 2017Page: e307-e308 Advertisement Copyright & Permissions© 2017MetricsAuthor Information Simon Bugeja More articles by this author Stella Ivaz More articles by this author Stacey Frost More articles by this author Mariya Dragova More articles by this author Daniela E Andrich More articles by this author Anthony R Mundy More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Enhanced aggressiveness of bystander cells in an anti-tumor photodynamic therapy model: Role of nitric oxide produced by targeted cells

The bystander effects of anti-cancer ionizing radiation have been widely studied, but far less is known about such effects in the case of non-ionizing photodynamic therapy (PDT). In the present study, we tested the hypothesis that photodynamically-stressed prostate cancer PC3 cells can elicit nitric oxide (NO)-mediated pro-growth/migration responses in non-stressed bystander cells. A novel approach was used whereby both cell populations existed on a culture dish, but made no physical contact with one other. Visible light irradiation of target cells sensitized with 5-aminolevulinic acid-induced protoporphyrin IX resulted in a striking upregulation of inducible nitric oxide synthase (iNOS) along with NO, the level of which increased after irradiation. Slower and less pronounced iNOS/NO upregulation was also observed in bystander cells. Activation of transcription factor NF-κB was implicated in iNOS induction in both targeted and bystander cells. Like surviving targeted cells, bystanders exhibited a significant increase in growth and migration rate, both responses being strongly attenuated by an iNOS inhibitor (1400W), a NO scavenger (cPTIO), or iNOS knockdown. Incubating bystander cells with conditioned medium from targeted cells failed to stimulate growth/migration, ruling out involvement of relatively long-lived stimulants. The following post-irradiation changes in pro-survival/pro-growth proteins were observed in bystander cells: upregulation of COX-2 and activation of protein kinases Akt and ERK1/2, NO again playing a key role. This is the first reported evidence for NO-enhanced bystander aggressiveness in the context of PDT. In the clinical setting, such effects could be averted through pharmacologic use of iNOS inhibitors as PDT adjuvants.

Structural and optical analysis of 60Co gamma-irradiated thin films of polycrystalline Ga10Se85Sn5

The present study focuses on the effects of gamma irradiation on structural and optical properties of polycrystalline Ga10Se85Sn5 thin films with a thickness of ∼300 nm deposited by the thermal evaporation technique on cleaned glass substrates. X-ray diffraction patterns of the investigated thin films show that crystallite growth occurs in the orthorhombic phase structure. The surface study carried out by using the scanning electron microscope (SEM) confirms that the grain size increases with gamma irradiation. The optical parameters were estimated from optical transmission spectra data measured from a UV–vis-spectrophotometer in the wavelength range of 200–1100 nm. The refractive index dispersion data of the investigated thin films follow the single oscillator model. The estimated values of static refractive index n0, oscillator strength Ed, zero frequency dielectric constant ε0, optical conductivity σoptical and the dissipation factor increases after irradiation, while the single oscillator energy Eo decreases after irradiation. It was found that the value of the optical band gap of the investigated thin films decreases and the corresponding absorption coefficient increases continuously with an increase in the dose of gamma irradiation. This post irradiation changes in the values of optical band gap and absorption coefficient were interpreted in terms of the bond distribution model.