49 resultados para ultraviolet-B radiation
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Photons participate in many atomic and molecular interactions and processes. Recent biophysical research has discovered an ultraweak radiation in biological tissues. It is now recognized that plants, animal and human cells emit this very weak biophotonic emission which can be readily measured with a sensitive photomultiplier system. UVA laser induced biophotonic emission of cultured cells was used in this report with the intention to detect biophysical changes between young and adult fibroblasts as well as between fibroblasts and keratinocytes. With suspension densities ranging from 1-8 x 106 cells/ml, it was evident that an increase of the UVA-laser-light induced photon emission intensity could be observed in young as well as adult fibroblastic cells. By the use of this method to determine ultraweak light emission, photons in cell suspensions in low volumes (100 microl) could be detected, in contrast to previous procedures using quantities up to 10 ml. Moreover, the analysis has been further refined by turning off the photomultiplier system electronically during irradiation leading to the first measurements of induced light emission in the cells after less than 10 micros instead of more than 100 milliseconds. These significant changes lead to an improvement factor up to 106 in comparison to classical detection procedures. In addition, different skin cells as fibroblasts and keratinocytes stemming from the same donor were measured using this new highly sensitive method in order to find new biophysical insight of light pathways. This is important in view to develop new strategies in biophotonics especially for use in alternative therapies.
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PURPOSE: Since 1982, the Radiation Oncology Group of the EORTC (EORTC ROG) has pursued an extensive Quality Assurance (QA) program involving all centres actively participating in its clinical research. The first step is the evaluation of the structure and of the human, technical and organisational resources of the centres, to assess their ability to comply with the current requirements for high-tech radiotherapy (RT). MATERIALS AND METHODS: A facility questionnaire (FQ) was developed in 1989 and adapted over the years to match the evolution of RT techniques. We report on the contents of the current FQ that was completed online by 98 active EORTC ROG member institutions from 19 countries, between December 2005 and October 2007. RESULTS: Similar to the data collected previously, large variations in equipment, staffing and workload between centres remain. Currently only 15 centres still use a Cobalt unit. All centres perform 3D Conformal RT, 79% of them can perform IMRT and 54% are able to deliver stereotactic RT. An external reference dosimetry audit (ERDA) was performed in 88% of the centres for photons and in 73% for electrons, but it was recent (<2 years) in only 74% and 60%, respectively. CONCLUSION: The use of the FQ helps maintain the minimum quality requirements within the EORTC ROG network: recommendations are made on the basis of the analysis of its results. The present analysis shows that modern RT techniques are widely implemented in the clinic but also that ERDA should be performed more frequently. Repeated assessment using the FQ is warranted to document the future evolution of the EORTC ROG institutions.
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AimThe study of adaptive radiations provides an evolutionary perspective on the interactions between organisms and their environment, and is necessary to understand global biodiversity. Adaptive radiations can sometimes be replicated over several disjunct geographical entities, but most examples are found on island or in lakes. Here, we investigated the biogeographical history of the clownfishes, a clade of coral reef fish with ranges that now span most of the Indo-Pacific Ocean, in order to explore the geographical structure of an unusual adaptive radiation. LocationIndian Ocean, Indo-Australian Archipelago (IAA) and Central Pacific Ocean. MethodsWe generated DNA sequence data comprising seven nuclear markers for 27 of the 30 clownfish species. We then inferred a Bayesian phylogeny and reconstructed the biogeographical history of the group using three different methods. Finally, we applied a biogeographical model of diversification to assess whether diversification patterns differ between the Indian and Pacific Oceans. ResultsThe phylogenetic tree is highly supported and allows reconstruction of the biogeographical history of the clade. While most species arose in the IAA, one clade colonized the eastern shores of Africa and diversified there. We found that the diversification rate of clownfishes does not differ between the main radiation and the African clade. Main conclusionsThe clownfishes first appeared and diversified in the IAA. Following a colonization event, a geographically independent radiation occurred in the Indian Ocean off East Africa. This rare example of replicated adaptive radiation in the marine realm provides intriguing possibilities for further research on ecological speciation in the sea.
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Aims and background. In 2002, a survey including 1759 patients treated from 1980 to 1998 established a "benchmark" Italian data source for prostate cancer radiotherapy. This report updates the previous one. Methods. Data on clinical management and outcomes of 3001 patients treated in 15 centers from 1999 through 2003 were analyzed and compared with those of the previous survey. Results. Significant differences in clinical management (-10% had abdominal ma-gnetic resonance imaging; +26% received ≥70 Gy, +48% conformal radiotherapy, -20% pelvic radiotherapy) and in G3-4 toxicity rates (-3.8%) were recorded. Actuarial 5-year overall, disease-specific, clinical relapse-free, and biochemical relapse-free survival rates were 88%, 96%, 96% and 88%, respectively. At multivariate analysis, D'Amico risk categories significantly impacted on all the outcomes; higher radiotherapy doses were significantly related with better overall survival rates, and a similar trend was evident for disease-specific and biochemical relapse-free survival; cumulative probability of 5-year late G1-4 toxicity was 24.8% and was significantly related to higher radiotherapy doses (P <0.001). Conclusions. The changing patterns of practice described seem related to an improvement in efficacy and safety of radiotherapy for prostate cancer. However, the impact of the new radiotherapy techniques should be prospectively evaluated.
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The late Variscan (275-278 Ma) Pribram uranium deposit is one of the largest known accumulations of uraniferous bitumens in hydrothermal veins. The deposit extends along the northwestern boundary of the Central Bohemian pluton (345-335 Ma) with low-grade metamorphosed Late Proterozoic and unmetamorphosed Cambrian rocks. From a net uranium production of 41,742 metric tons (t), more than 6,000 t were extracted from bitumen-uraninite ores during 43 years of exploration and mining. Three morphological varieties of solid bitumen are recognized: globular, asphaltlike, and cokelike. While the globular bitumen is uranium free, the other two types are uraniferous. The amount of bitumen in ore veins gradually decreases toward the contact with the plutonic body and increases with depth. Two types of bitumen microtextures are recognized using high-resolution transmission electron microscopy: amorphous and microporous, the former being less common in uraniferous samples. A lower Raman peak area ratio (1,360/1,575 cm(-1)) in mineralized bitumens (0.9) compared with uranium-free samples (2.0) indicates a lower degree of microtextural organization in the latter The H/C and O/C atomic ratios in uranium-free bitumens (0.9-1.1 and 0.09, respectively) are higher than those in mineralized samples (H/C = 0.3-0.8, O/C = 0.03-0.09). The chloroform extractable matter yield is Very low in uranium-free bitumens (0.30-0.35% of the total organic carbon,TOC) and decreases with uranium content increase. The extracted solid uraniferous bitumen infrared spectra show depletion in aliphatic CH2 and CH3 groups compared to uranium-free samples. The concentration of oxygen-bearing functional groups relative to aromatic bonds in the IR spectra of uranium-free and mineralized bitumen, however, do not differ significantly. C-13 NMR confirmed than the aromaticity of a uraniferous sample is higher (F-ar = 0.61) than in the uranium-free bitumen (F-ar = 0.51). Pyrolysates from uraniferous and nonuraniferous bitumens do not differ significantly, being predominantly cresol, alkylphenols, alkylbenzenes, and alkylnaphthalenes. The liquid pyrolysate yield decreases significantly with increasing uranium content. The delta(13)C Values of bulk uranium-free bitumens and low-grade uraniferous, asphaltlike bitumens range from -43.6 to 52.3 per mil. High-grade, cokelike, uraniferous bitumens are more C-13 depleted (54.5 to -58.4 parts per thousand). In contrast to the very light isotopic ratios of the high-grade uraniferous cokelike bitumen bulk carbon, the individual n-alkanes and isoprenoids (pristane and phytane) extracted from the same sample are significantly C-13 enriched. The isotopic composition of the C13-24 n-alkanes extracted from the high-grade uraniferous sample (delta(13)C = -28.0 to 32.6 parts per thousand) are heavier compared with the same compounds in a uranium-free sample (delta(13)C = 31.9 to 33.8 parts per thousand). It is proposed that the bitumen source was the isotopically light (delta(13)C = 35.8 to 30.2 parts per thousand) organic matter of the Upper Proterozoic host rocks that were pyrolyzed during intrusion of the Central Bohemian pluton. The C-13- depleted pyrolysates were mobilized from the innermost part of the contact-metamorphic aureole, accumulated in structural traps in less thermally influenced parts of the sedimentary complex and were later extracted by hydrothermal fluids. Bitumens at the Pribram deposit are younger than the main part of the uranium mineralization and were formed through water-washing and radiation-induced polymerization of both the gaseous and liquid pyrolysates. Direct evidence for pyrolysate reduction of uranium in the hydrothermal system is difficult to obtain as the chemical composition of the original organic fluid phase was modified during water-washing and radiolytic alteration. However, indirect evidence-e.g., higher O/C atomic ratios in uranium-free bitumens (0.1) relative to the Upper Proterozoic source rocks (0.02-0.05), isotopically very light carbon in associated whewellite (delta(13)C = 31.7 to -28.4 parts per thousand), and the striking absence of bitumens in the pre-uranium, hematite stage of the mineralization-indicates that oxidation of organic fluids may have contributed to lowering of aO(2) and uraninite precipitation.
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ABSTRACT: BACKGROUND: Adaptive radiation is the process by which a single ancestral species diversifies into many descendants adapted to exploit a wide range of habitats. The appearance of ecological opportunities, or the colonisation or adaptation to novel ecological resources, has been documented to promote adaptive radiation in many classic examples. Mutualistic interactions allow species to access resources untapped by competitors, but evidence shows that the effect of mutualism on species diversification can greatly vary among mutualistic systems. Here, we test whether the development of obligate mutualism with sea anemones allowed the clownfishes to radiate adaptively across the Indian and western Pacific oceans reef habitats. RESULTS: We show that clownfishes morphological characters are linked with ecological niches associated with the sea anemones. This pattern is consistent with the ecological speciation hypothesis. Furthermore, the clownfishes show an increase in the rate of species diversification as well as rate of morphological evolution compared to their closest relatives without anemone mutualistic associations. CONCLUSIONS: The effect of mutualism on species diversification has only been studied in a limited number of groups. We present a case of adaptive radiation where mutualistic interaction is the likely key innovation, providing new insights into the mechanisms involved in the buildup of biodiversity. Due to a lack of barriers to dispersal, ecological speciation is rare in marine environments. Particular life-history characteristics of clownfishes likely reinforced reproductive isolation between populations, allowing rapid species diversification.
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Purpose: Cystoid macular oedema (CMO) is a very rare condition following cataract surgery in paediatric population. Nevertheless, we report a case series of patients with radiation induced cataract after retinoblastoma (Rb) treatment that underwent cataract surgery and developed subsequently late onset CMO. Methods: Between January 1984 and December 2009, 25 consecutive eyes (25 patients) with Rb presented with radiation induced cataract surgery at the Jules Gonin Eye Hospital. Sixteen eyes (16 patients) had prior radiation induced retinopathy and maculopathy (IRM). Out of these, 3 eyes (3 patients) developed CMO after cataract surgery. Results: One eye had Rb stage B, and 2 eyes had stage D International classification. All of them developed IRM following brachytherapy and/or external beam irradiation. Patients underwent phako-aspiration and in bag intraocular lens implantation after IRM had resolved. Mean age at cataract surgery was 10.7 ± 2.8 (SEM) (range 5-14) years old. Mean time between resolution of IRM and cataract surgery was 76.0 ± 27.2 (SEM) (range 24-116) months. Mean time of onset CMO after cataract surgery was 81.0 ± 34.4 (SEM) (range 13-124) months. There was no other underlying vascular or tractional factor for CMO development. All of them were treated with a combination of oral carbonic anhydrase inhibitor, topical steroid and topical non-steroid. Mean macular thickness pre-, during-, and post CMO were 134.0 ± 10.3, 298.0 ± 37.1, and 154.0 ± 4.0 (SEM) µm, respectively. Mean best corrected visual acuity pre-, during-, and post CMO were 0.31 ± 0.19, 0.46 ± 0.12, and 0.34 ± 0.18 (SEM) LogMAR, respectively. Mean time for CMO reabsorption was 17.0 ± 9.8 (SEM) months. Conclusions: To the best of our knowledge, CMO following paediatric cataract surgery is a very uncommon condition. Moreover, late onset CMO after phako-aspiration for radiation induced cataract in Rb patients has never been described. It is a rare complication but can be treated successfully.
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Bacteria are generally difficult specimens to prepare for conventional resin section electron microscopy and mycobacteria, with their thick and complex cell envelope layers being especially prone to artefacts. Here we made a systematic comparison of different methods for preparing Mycobacterium smegmatis for thin section electron microscopy analysis. These methods were: (1) conventional preparation by fixatives and epoxy resins at ambient temperature. (2) Tokuyasu cryo-section of chemically fixed bacteria. (3) rapid freezing followed by freeze substitution and embedding in epoxy resin at room temperature or (4) combined with Lowicryl HM20 embedding and ultraviolet (UV) polymerization at low temperature and (5) CEMOVIS, or cryo electron microscopy of vitreous sections. The best preservation of bacteria was obtained with the cryo electron microscopy of vitreous sections method, as expected, especially with respect to the preservation of the cell envelope and lipid bodies. By comparison with cryo electron microscopy of vitreous sections both the conventional and Tokuyasu methods produced different, undesirable artefacts. The two different types of freeze-substitution protocols showed variable preservation of the cell envelope but gave acceptable preservation of the cytoplasm, but not lipid bodies, and bacterial DNA. In conclusion although cryo electron microscopy of vitreous sections must be considered the 'gold standard' among sectioning methods for electron microscopy, because it avoids solvents and stains, the use of optimally prepared freeze substitution also offers some advantages for ultrastructural analysis of bacteria.
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BACKGROUND: Sorafenib (Sb) is a multiple kinase inhibitor targeting both tumour cell proliferation and angiogenesis that may further act as a potent radiosensitizer by arresting cells in the most radiosensitive cell cycle phase. This phase I open-label, noncontrolled dose escalation study was performed to determine the safety and maximum tolerated dose (MTD) of Sb in combination with radiation therapy (RT) and temozolomide (TMZ) in 17 patients with newly diagnosed high-grade glioma. METHODS: Patients were treated with RT (60 Gy in 2 Gy fractions) combined with TMZ 75 mg m(-2) daily, and Sb administered at three dose levels (200 mg daily, 200 mg BID, and 400 mg BID) starting on day 8 of RT. Thirty days after the end of RT, patients received monthly TMZ (150-200 mg m(-2) D1-5/28) and Sb (400 mg BID). Pharmacokinetic (PK) analyses were performed on day 8 (TMZ) and on day 21 (TMZ&Sb) (Clinicaltrials ID: NCT00884416). RESULTS: The MTD of Sb was established at 200 mg BID. Dose-limiting toxicities included thrombocytopenia (two patients), diarrhoea (one patient) and hypercholesterolaemia (one patient). Sb administration did not affect the mean area under the curve(0-24) and mean Cmax of TMZ and its metabolite 5-amino-imidazole-4-carboxamide (AIC). Tmax of both TMZ and AIC was delayed from 0.75 (TMZ alone) to 1.5 h (combined TMZ/Sb). The median progression-free survival was 7.9 months (95% confidence interval (CI): 5.4-14.55), and the median overall survival was 17.8 months (95% CI: 14.7-25.6). CONCLUSIONS: Although Sb can be combined with RT and TMZ, significant side effects and moderate outcome results do not support further clinical development in malignant gliomas. The robust PK data of the TMZ/Sb combination could be useful in other cancer settings.
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OBJECTIVE: Examination of the rate of grade III or grade IV radiation dermatitis during treatment of head and neck cancer (HNC) with radiotherapy (RT) and concurrent cetuximab in EORTC centres. MATERIALS AND METHOD: A questionnaire was sent to all members of the EORTC Radiation Oncology Group and Head and Neck Group (111 institutions) to evaluate the widespread use of cetuximab and radiotherapy in HNC and to estimate the frequency of grades III and IV skin reactions in the radiation portals associated with this protocol. Co-morbidities, RT schedules and co-medications were also recorded. RESULTS: We received responses from 28 institutions in 11 countries. A total of 125 HNC patients from 15 institutions were treated with cetuximab and concurrent RT. Information about the skin reactions was available from 71 patients. Of these 36 had no grade III/IV adverse effects in the RT field, 15 had a grade III and 20 had grade IV radiation dermatitis. No detectable relation of grades III and IV radiation dermatitis with co-morbidities such as liver insufficiency or renal dysfunction was found. CONCLUSION: According to the results of the questionnaire, grade III/IV radiation dermatitis is observed in 49% of HNC patients treated with cetuximab and concurrent RT. A systematic clinical monitoring of cutaneous side effects during RT plus cetuximab is advised to ensure the safety of this protocol.
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PURPOSE: Ocular anatomy and radiation-associated toxicities provide unique challenges for external beam radiation therapy. For treatment planning, precise modeling of organs at risk and tumor volume are crucial. Development of a precise eye model and automatic adaptation of this model to patients' anatomy remain problematic because of organ shape variability. This work introduces the application of a 3-dimensional (3D) statistical shape model as a novel method for precise eye modeling for external beam radiation therapy of intraocular tumors. METHODS AND MATERIALS: Manual and automatic segmentations were compared for 17 patients, based on head computed tomography (CT) volume scans. A 3D statistical shape model of the cornea, lens, and sclera as well as of the optic disc position was developed. Furthermore, an active shape model was built to enable automatic fitting of the eye model to CT slice stacks. Cross-validation was performed based on leave-one-out tests for all training shapes by measuring dice coefficients and mean segmentation errors between automatic segmentation and manual segmentation by an expert. RESULTS: Cross-validation revealed a dice similarity of 95% ± 2% for the sclera and cornea and 91% ± 2% for the lens. Overall, mean segmentation error was found to be 0.3 ± 0.1 mm. Average segmentation time was 14 ± 2 s on a standard personal computer. CONCLUSIONS: Our results show that the solution presented outperforms state-of-the-art methods in terms of accuracy, reliability, and robustness. Moreover, the eye model shape as well as its variability is learned from a training set rather than by making shape assumptions (eg, as with the spherical or elliptical model). Therefore, the model appears to be capable of modeling nonspherically and nonelliptically shaped eyes.
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Background: Preclinical data indicate activity of mammalian target of rapamycin inhibitors and synergistic activity together with radiotherapy in glioblastoma. The aim of this trial is to assess the therapeutic activity of temsirolimus (CCI-779), an intravenous mTOR inhibitor, in patients with newly diagnosed glioblastoma with unmethylated O6 methlyguanine-DNA-methlytransferase (MGMT)promoter. Methods: Patients (n=257) with newly diagnosed glioblastoma after open surgical biopsy or resection fulfilling basic eligibility criteria underwent a central MGMT promoter analysis using quantitative methylation specific PCR. Patients with glioblastoma harboring an unmethylated MGMT promoter (n=111) were randomized 1:1 between radiotherapy (60 Gy; 5 times 2 Gy per week) plus concomitant and six cycles of maintenance temozolomide or radiotherapy plus weekly temsirolimus at 25 mg flat dose to be continued until progression or undue toxicity. Primary endpoint was overall survival at 12 months (OS12). Sample size of the investigational treatment arm required 54 patients to assess adequacy of temsirolimus activity set at 80%. More than 38 patients alive at 12 months in the per protocol population was considered a positive signal. A control arm of 54 patients treated with the standard of care was implemented to evaluate the assumptions on OS12. Results: Between December 2009 and October 2012, 111 pts in 14 centers were randomized and treated. Median age was 55 and 58 years in the temsirolimus and standard arm, respectively. Most patients (95.5%) had a WHO performance status of 0 or 1. Both therapies were properly administered with a median of 13 cycles of maintenance temsirolimus. In the per protocolpopulation, exactly 38 patients treated with temsirolimus (out of 54 eligible) reached OS12. In the intention to treat population OS12 was 72.2% [95% CI (58.2, 82.2)] in the temozolomide arm and 69.6% [95% CI (55.8, 79.9) in the temsirolimus arm [HR=1.16 95% CI (0.77, 1.76), p=0.47]. Conclusions: The therapeutic activity of temsirolimus in patients with newly diagnosed glioblastoma with an unmethylated MGMT promoter is too low.
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Purpose. To evaluate the impact of mobile devices and apps on the daily clinical activity of young radiation oncologists. Methods. A web-based questionnaire was sent to 382 young (≤40 years) members of the Italian Association of Radiation Oncology (AIRO). The 14 items investigated the diffusion of mobile devices (smartphones and/or tablets), their impact on daily clinical activity, and possible differences perceived by the participants over time. Results. A total of 158 questionnaires were available for statistical evaluation (response rate 41%). Up to 75% of respondents declared they used an electronic device during their clinical activity. Conversely, 82% considered the impact of smartphones/tables on daily practice low to moderate. Daily device use increased significantly from 2009 to 2012, with high daily use rates rising from 5% to 39.9%. Fulfillment of professional needs was declared by less than 42% of respondents and compliance with app indications by 32%. Almost all physicians desired in 2012 a comprehensive website concerning a variety of apps covering radiation oncologists' needs. Conclusions. Mobile devices are widely used by young Italian radiation oncologists in their daily clinical practice, while the indications so obtained are not always followed. Nevertheless, it would be important to verify the consistency of information found within apps, in order to avoid potential errors that might be detrimental to patients.