Dosimetric evaluation of scattered and attenuated radiation due to dental restorations in head and neck radiotherapy

Abstract In radiotherapy of head and neck cancer, the presence of high density materials modifies photon dose distribution near these high density materials during treatment. The aim of this study is to calculate the backscatter and attenuation effects of a healthy tooth, Amalgam, Ni-Cr alloy and Ceramco on the normal tissues before and after these materials irradiated by 6 and 15 MV photon beams, respectively. All measurements were carried out in a water phantom with dimension of 50 × 50 × 50 cm 3 with an ionization chamber detector. Two points before and four points after the dental sample were considered to score the photon dose. The depth dose on the central beam axis was explored in a water phantom for source to surface distance (SSD) of 100 cm in a 10 × 10 cm 2 field size. The percentage dose change was obtained relative to the dose in water versus depth of water, tooth, Amalgam, Ni-Cr alloy and Ceramco for the photon beams. The absolute dose (cGy) was measured by prescription of 100 cGy dose in the water phantom at depth of 2.0 and 3.1 cm for 6 and 15 MV photons, respectively. At depth of 0.6 cm, the maximum percentage dose increase was observed with values of 6.99% and 9.43%for Ni-Cr and lowest percentage dose increase of 1.49% and 2.63% are related to the healthy tooth in 6 and 15 MV photon beams, respectively. The maximum absolute dose of 95.58 cGy and 93.64 cGy were observed at depth of 0.6 cm in presence of Ni-Cr alloy for 6 and 15 MV photon beams, respectively. The presence of dental restorations can cause backscattering dose during head and neck radiation therapy. Introduction of compositions and electron density of high density materials can improve the accuracy of dosimetric calculations in treatment planning systems to deliver the relevant dose to target organ and reduce the backscattering dose in healthy tissues in the surrounding of tooth

Mucosal interleukin-21 mRNA expression level is high in patients with Helicobacter pylori and is associated with the severity of gastritis

Helicobacter pylori (H. pylori) infection is associated with gastritis and marked infiltration of the gastric mucosa by several cytokines secreting inflammatory cells. Different clinical forms of the infection may reflect distinctive patterns of cytokine expression. Interleukin (IL)-17, IL-21, IL-22, and IL-23 have been reported to be involved in H. pylori-induced gastric mucosal inflammation, but the details and relationship to different patterns of inflammation and virulence factors remain unclear. The present study was launched to analyse IL-6 expression in H. pylori-infected and uninfected gastric patients and to investigate its correlation with chronic gastritis among H. pylori-infected patients. Total RNA was extracted from the gastric antrum biopsies of 48 H. pylori-infected patients and 38 H. pylori uninfected patients. Mucosal IL-21 mRNA expression level in H. pylori-infected and uninfected gastric biopsy was determined by real-time PCR. The presence of vacA (vacuolating cytotoxin A) and cagA (cytotoxin associated gene A) virulence factors were evaluated using PCR. Interleukin-21 mRNA expression was significantly high in biopsies of H. pylori-infected patients compared to H. pylori uninfected patients, and the mucosal IL-21 mRNA level was positively correlated with the grade of chronic inflammation. There was no association between virulence factors and IL-21 mRNA expression. We believe that IL-21 might be involved in the pathogenesis of H. pylori and might be an index of the severity of chronic gastritis

Frequency of virulence factors in Helicobacter pylori-infected patients with gastritis

The outcome of Helicobacter pylori infection has been related to specific virulence-associated bacterial genotypes. The vacuolating cytotoxin (vacA), cagA gene, oipA and babA2 gene are important virulence factor involving gastric diseases. The objective of this study was to assess the relationship between virulence factors of H. pylori and histopathological findings. Material and methods: Gastroduodenoscopy was performed in 436 dyspeptic patients. Antrum biopsy was obtained for detection of H. pylori, virulence factors and for histopathological assessment. The polymerase chain reaction was used to detect virulence factors of H. pylori using specific primers. Results: vacA genotypes in patients infected with H. pylori were associated with cagA, iceA1 and iceA2. In the patients with H. pylori infection there was a significant relationship between cagA positivity and neutrophil activity (P = 0.004) and chronic inflammation (P = 0.013) and with H. pylori density (P = 0.034). Neutrophil infiltration was found to be more severe in the s1 group than in the s2 group (P = 0.042). Also was a significant relationship between oipA positivity and neutrophil activity (P = 0.004) and with H. pylori density (P = 0.018). No significant relationships were observed between other vacA genotypes and histopathological parameters. Conclusion: H. pylori strains showing cagA, vacA s1 and oipA positivity are associated with more severe gastritis in some histological features but virulence factors of H. pylori do not appear to determine the overall pattern of gastritis. (C) 2015 Elsevier Ltd. All rights reserved

Evaluation of IL-17A and IL-17F genes polymorphism in Iranian dyspeptic patients

Helicobacter pylori (H.pylori) colonize the gastric mucosa of approximately 50 of the world's population that involved in chronic gastritis. The relationship between Hp colonization and gastric inflammation is widely accepted. Polymorphisms in inflammation related genes such as cytokines were thought to partly determine the outcome of Hp infection and progression of gastritis. Interleukin IL -17A and IL-17F are inflammatory cytokines expressed by a novel subset of CD4+ Th cells, play important function in inflammation. Aimed: we evaluate association of IL-17A G197A and IL-17F A7488G polymorphisms with gastritis, Polymorphonuclear (PMN) and Monoculear (MN) infiltration in related to Hp. Methods: According to rapid urease test, PCR 16srRNA, urea and histological examination of biopsies, patients were classified Hp-infected and Hp-uninfected. The histological severity of gastritis was graded from normal to severe based on the degree of MN cell and PMN leukocyte infiltration, chronic gastritis and chronic active gastritis. Polymorphism in IL-17A G197A and IL-17F A7488G were evaluated by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Results: AG, GG, AG/AA carriers of IL-17A G197A and AA, GA, GG, GA/GG carriers of IL-17F A7488G polymorphisms were not associated with MN infiltration, PMN infiltration, chronic gastritis and Chronic active gastritis in Hp-infected and Hp-uninfected groups (p > 0.05). AA genotype of IL-17A G197A was related to chronic gastritis and PMN infiltration in Hp-uninfected group. Conclusion: IL-17A G197A substitution may be a risk factor for development gastritis in Hp-uninfected patients, also affect the pathway MN cell production pathways

Evaluation of H.pylori infection and IL23R gene polymorphism in dyspeptic subjects

CagA strains of H.pylori (Hp) are known to be associated with gastroduodenal diseases. Polymorphisms in inflammation related genes, such as cytokines and their receptors, were thought to partly determine the outcome of Hp infection and the progression of gastritis. It is supposed that interleukin 23 receptor (IL23R), a basic cytokine receptor in the inflammatory IL-17/IL-23 axis, may be related to gastritis. In the present study, we evaluated the association of IL23R +2199 rs10889677 polymorphism and cagA positivity with chronic gastritis. In addition, we studied the infiltration of polymorphonuclear (PMN) and mononuclear (MN) Leukocytes into surrounding tissues of corpus. Biopsies taken from the corpus of the patients were classified as two groups: Hp-infected and Hpuninfected. The severity of gastritis was graded from normal to severe, chronic gastritis and chronic active gastritis. Virulence factor, cagA, was evaluated using PCR and the polymorphism in IL23R was investigated by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). AA and AC carriers of IL23R +2199 polymorphism, but not CC genotype in Hp-uninfected patients, were not associated with cellular infiltration and gastritis in both groups (p > 0.05). CagA positivity was significantly associated with increased risk of PMN (P= 0.013), but not with MN infiltration (P= 0.069). Also gastritis was found to be associated with cagA positivity (P= 0.044). Our results show decreased Hp infection probability in patients with CC genotype of 2199 +IL23R. According to the clinical and pathological features in Hp-infected group, IL23R polymorphism doesn't influence chronic gastritis and chronic active gastritis

Investigation of Planar Channeling Radiation on Diamond and Quartz Crystals at Electron Energies between 14 and 34 MeV and Probing the Influence of Ultrasonic Waves on Channeling Radiation

The first measurements of CR at the Radiation source ELBE of the Forschungszentrum Dresden-Rossendorf have been performed in the fall of 2003, where the most important attempt for an application of CR in radiobiological research was the optimization of its yield and spectral line width as well. Since diamond single crystals have been found to probably be the most suitable ones for an intense CR production because of their outstanding properties to withstand rather high average electron currents, a first measurement series was directed to the studying of the dependence of the yield of planar CR on the thickness of the diamond crystal

Investigation of Planar Channeling Radiation on Diamond and Quartz Crystals at Electron Energies between 14 and 34 MeV and Probing the Influence of Ultrasonic Waves on Channeling Radiation

The first measurements of CR at the Radiation source ELBE of the Forschungszentrum Dresden-Rossendorf have been performed in the fall of 2003, where the most important attempt for an application of CR in radiobiological research was the optimization of its yield and spectral line width as well. Since diamond single crystals have been found to probably be the most suitable ones for an intense CR production because of their outstanding properties to withstand rather high average electron currents, a first measurement series was directed to the studying of the dependence of the yield of planar CR on the thickness of the diamond crystal

New insight to IL-23/IL-17 axis in Iranian infected adult patients with gastritis : effects of genes polymorphisms on expression of cytokines

Background and Objective : Chronic inflammation is the hallmark of the pathogenesis of H. pylori-induced gastric cancer. IL-17A and IL-17F are inflammatory cytokines expressed by a novel subset of CD4(+)Th cells and play critical function in inflammation. We evaluated the relationship between IL-17A G197A, IL-17F A7488G and IL23R+2199 A/C polymorphisms with IL-6, IL-17, IL-21, IL-23 and TGF-beta 1 mRNAs expression in regard to H. pylori infection with chronic gastritis. Materials and Methods : Total RNA and genomic DNA were extracted from gastric biopsies of 58 H. pylori-infected patient with gastritis. Afterward, mucosal IL-6, IL-17, IL-21, IL-23 and TGF-beta 1 mRNAs expression and polymorphisms in IL-17A G197A, IL-17F A7488G and IL-23R +2199A/Cin gastric biopsies were determined by real-time PCR and PCR-RFLP. Results : Our results show that IL-17A G197A, IL-17F A7488G andIL23R +2199A/C polymorphisms have no effect on mucosal expression of IL-6, IL-17, IL-21 and TGF-beta 1 mRNAs expression in H. pylori-infected patients with chronic gastritis. Conclusion : These results suggest that IL-17A G197A, IL-17F A7488G and IL23R +2199A/C polymorphisms no alter mucosal cytokine pattern in Iranian patients with H. pylori-associated gastritis diseases