297 research outputs found
Validating the Dosimetric Parameters of INTRABEAM Intraoperative Radiotherapy Machine
BACKGROUND AND OBJECTIVE: One of the methods for treating breast cancer is radiotherapy using low-kV X-rays in which a dedicated device called INTRABEAM is used along with a few spherical applicators for breast radiation. Due to the single-session nature of this treatment, evaluating the accuracy of the device used for treatment is essential. The aim of this study was to evaluate the dosimetric parameters of the INTRABEAM system with spherical applicators and validate the reported results for clinical use in intraoperative radiotherapy for breast tumors.
METHODS: In this study, dosimetric parameters including percentage depth dose curve (PDD), transfer function (TF) and anisotropy were determined by MCNPX Monte Carlo Simulation Tool and practical dosimetry was done by Gafchromic EBT2 film. The results were quantitatively compared with the results reported by manufacturer of the device (Carl Zeiss) to evaluate the accuracy of the reported data for this treatment system.
FINDINGS: The mean difference when comparing PDD curves was 1.7% and the mean difference between the compared TF values was about 2%. The anisotropy values obtained by Monte Carlo Simulation and Gafchromic EBT2 film were also within the range recommended by the manufacturer.
CONCLUSION: Based on the results, it can be concluded that the dosimetric parameters reported by the manufacturer for spherical applicators of the INTRABEAM system are valid for designing the treatment and radiotherapy for patients
Energy loss in a strongly coupled anisotropic plasma
We study the energy loss of a rotating infinitely massive quark moving, at
constant velocity, through an anisotropic strongly-coupled N=4 plasma from
holography. It is shown that, similar to the isotropic plasma, the energy loss
of the rotating quark is due to either the drag force or radiation with a
continuous crossover from drag-dominated regime to the radiation dominated
regime. We find that the anisotropy has a significant effect on the energy loss
of the heavy quark, specially in the crossover regime. We argue that the energy
loss due to radiation in anisotropic media is less than the isotropic case.
Interestingly this is similar to analogous calculations for the energy loss in
weakly coupled anisotropic plasma.Comment: 26+1 pages, 10 figures, typos fixe
Hereditary risk factors for the development of gastric cancer in younger patients
BACKGROUND: It is believed that the development of gastric cancer (GC) before the age of 50 has a hereditary basis. Blood group A and history of gastric cancer in first-degree relatives have been shown to be risk factors for GC. METHODS: In this case-control study, we enrolled patients with GC who were diagnosed before the age of 50. Patients who were diagnosed as having GC were selected. A total of 534 cases were found; of these, 44 diagnosed before the age of 50 were included in the case group. For the control group, 22 males and 22 females were randomly selected from the remaining subjects, who had diagnoses of GC after the age of 50. All the surviving patients and family members of the dead patients were interviewed about the history of cancer in the family and the age at which other family members developed cancer. The blood group of each subject was also obtained. RESULTS: forty-four cases under 50 years old (mean age: 36.2 years) and forty-four controls (mean age: 67.1 years) were enrolled in the study. At the time of the study, 59.1% of the study group and 50% of the control group were alive (P value = NS). In the study group, 68.1%, 13.6%, 13.6% and 4.5% had blood groups O, A, B and AB, respectively. In the control group the corresponding figures were 27.7%, 63.6%, 6.8% and 4.5%. First or second-degree relatives with cancer, including gastric (the most frequent), breast, lung, gynecological and hematological malignancies, were noted in 54.5% of the cases and 11.4% of the controls (p < 0.01). Family histories of cancer were accepted as valid provided that they were based on valid medical documents. CONCLUSIONS: It seems that the development of GC before the age of 50 is likely to be accompanied by familial susceptibility. Interestingly, our study showed a significant correlation between blood group O and the development of gastric cancer under the age of 50
Petri Net computational modelling of Langerhans cell Interferon Regulatory Factor Network predicts their role in T cell activation
Langerhans cells (LCs) are able to orchestrate adaptive immune responses in the skin by interpreting the microenvironmental context in which they encounter foreign substances, but the regulatory basis for this has not been established. Utilising systems immunology approaches combining in silico modelling of a reconstructed gene regulatory network (GRN) with in vitro validation of the predictions, we sought to determine the mechanisms of regulation of immune responses in human primary LCs. The key role of Interferon regulatory factors (IRFs) as controllers of the human Langerhans cell response to epidermal cytokines was revealed by whole transcriptome analysis. Applying Boolean logic we assembled a Petri net-based model of the IRF-GRN which provides molecular pathway predictions for the induction of different transcriptional programmes in LCs. In silico simulations performed after model parameterisation with transcription factor expression values predicted that human LC activation of antigen-specific CD8 T cells would be differentially regulated by epidermal cytokine induction of specific IRF-controlled pathways. This was confirmed by in vitro measurement of IFN-g production by activated T cells. As a proof of concept, this approach shows that stochastic modelling of a specific immune networks renders transcriptome data valuable for the prediction of functional outcomes of immune responses
The requirements and challenges in preventing of road traffic injury in Iran. A qualitative study
<p>Abstract</p> <p>Background</p> <p>Road traffic injuries (RTIs) are a major public health problem, especially in low- and middle-income countries. Among middle-income countries, Iran has one of the highest mortality rates from RTIs. Action is critical to combat this major public health problem. Stakeholders involved in RTI control are of key importance and their perceptions of barriers and facilitators are a vital source of knowledge. The aim of this study was to explore barriers to the prevention of RTIs and provide appropriate suggestions for prevention, based on the perceptions of stakeholders, victims and road-users as regards RTIs.</p> <p>Methods</p> <p>Thirty-eight semi-structured interviews were conducted with informants in the field of RTI prevention including: police officers; public health professionals; experts from the road administrators; representatives from the General Governor, the car industry, firefighters; experts from Emergency Medical Service and the Red Crescent; and some motorcyclists and car drivers as well as victims of RTIs. A qualitative approach using grounded theory method was employed to analyze the material gathered.</p> <p>Results</p> <p>The core variable was identified as "The lack of a system approach to road-user safety". The following barriers in relation to RTI prevention were identified as: human factors; transportation system; and organizational coordination. Suggestions for improvement included education (for the general public and targeted group training), more effective legislation, more rigorous law enforcement, improved engineering in road infrastructure, and an integrated organization to supervise and coordinate preventive activities.</p> <p>Conclusion</p> <p>The major barriers identified in this study were human factors and efforts to change human behaviour were suggested by means of public education campaigns and stricter law enforcement. However, the lack of a system approach to RTI prevention was also an important concern. There is an urgent need for both an integrated system to coordinate RTI activities and prevention and a major change in stakeholders' attitudes towards RTI prevention. The focus of all activities should take place on road users' safety.</p
An Alternate STAT6-Independent Pathway Promotes Eosinophil Influx into Blood during Allergic Airway Inflammation
Enhanced eosinophil responses have critical roles in the development of allergic diseases. IL-5 regulates the maturation, migration and survival of eosinophils, and IL-5 and eotaxins mediate the trafficking and activation of eosinophils in inflamed tissues. CD4βΊ Th2 cells are the main producers of IL-5 and other cells such as NK also release this cytokine. Although multiple signalling pathways may be involved, STAT6 critically regulates the differentiation and cytokine production of Th2 cells and the expression of eotaxins. Nevertheless, the mechanisms that mediate different parts of the eosinophilic inflammatory process in different tissues in allergic airway diseases remain unclear. Furthermore, the mechanisms at play may vary depending on the context of inflammation and microenvironment of the involved tissues. We employed a model of allergic airway disease in wild type and STAT6-deficient mice to explore the roles of STAT6 and IL-5 in the development of eosinophilic inflammation in this context. Quantitative PCR and ELISA were used to examine IL-5, eotaxins levels in serum and lungs. Eosinophils in lung, peripheral blood and bone marrow were characterized by morphological properties. CD4βΊ T cell and NK cells were identified by flow cytometry. Antibodies were used to deplete CD4βΊ and NK cells. We showed that STAT6 is indispensible for eosinophilic lung inflammation and the induction of eotaxin-1 and -2 during allergic airway inflammation. In the absence of these chemokines eosinophils are not attracted into lung and accumulate in peripheral blood. We also demonstrate the existence of an alternate STAT6-independent pathway of IL-5 production by CD4βΊ and NK cells that mediates the development of eosinophils in bone marrow and their subsequent movement into the circulation
Context Differences Reveal Insulator and Activator Functions of a Su(Hw) Binding Region
Insulators are DNA elements that divide chromosomes into independent transcriptional domains. The Drosophila genome contains hundreds of binding sites for the Suppressor of Hairy-wing [Su(Hw)] insulator protein, corresponding to locations of the retroviral gypsy insulator and non-gypsy binding regions (BRs). The first non-gypsy BR identified, 1A-2, resides in cytological region 1A. Using a quantitative transgene system, we show that 1A-2 is a composite insulator containing enhancer blocking and facilitator elements. We discovered that 1A-2 separates the yellow (y) gene from a previously unannotated, non-coding RNA gene, named yar for y-achaete (ac) intergenic RNA. The role of 1A-2 was elucidated using homologous recombination to excise these sequences from the natural location, representing the first deletion of any Su(Hw) BR in the genome. Loss of 1A-2 reduced yar RNA accumulation, without affecting mRNA levels from the neighboring y and ac genes. These data indicate that within the 1A region, 1A-2 acts an activator of yar transcription. Taken together, these studies reveal that the properties of 1A-2 are context-dependent, as this element has both insulator and enhancer activities. These findings imply that the function of non-gypsy Su(Hw) BRs depends on the genomic environment, predicting that Su(Hw) BRs represent a diverse collection of genomic regulatory elements
Chemosensitivity Predicted by BluePrint 80-Gene Functional Subtype and MammaPrint in the Prospective Neoadjuvant Breast Registry Symphony Trial (NBRST)
PURPOSE: The purpose of the NBRST study is to compare a multigene classifier to conventional immunohistochemistry (IHC)/fluorescence in situ hybridization (FISH) subtyping to predict chemosensitivity as defined by pathological complete response (pCR) or endocrine sensitivity as defined by partial response. METHODS: The study includes women with histologically proven breast cancer, who will receive neoadjuvant chemotherapy (NCT) or neoadjuvant endocrine therapy. BluePrint in combination with MammaPrint classifies patients into four molecular subgroups: Luminal A, Luminal B, HER2, and Basal. RESULTS: A total of 426 patients had definitive surgery. Thirty-seven of 211 (18Β %) IHC/FISH hormone receptor (HR)+/HER2β patients were reclassified by Blueprint as Basal (nΒ =Β 35) or HER2 (nΒ =Β 2). Fifty-three of 123 (43Β %) IHC/FISH HER2+ patients were reclassified as Luminal (nΒ =Β 36) or Basal (nΒ =Β 17). Four of 92 (4Β %) IHC/FISH triple-negative (TN) patients were reclassified as Luminal (nΒ =Β 2) or HER2 (nΒ =Β 2). NCT pCR rates were 2Β % in Luminal A and 7Β % Luminal B patients versus 10Β % pCR in IHC/FISH HR+/HER2β patients. The NCT pCR rate was 53Β % in BluePrint HER2 patients. This is significantly superior (pΒ =Β 0.047) to the pCR rate in IHC/FISH HER2+ patients (38Β %). The pCR rate of 36 of 75 IHC/FISH HER2+/HR+ patients reclassified as BPLuminal is 3Β %. NCT pCR for BluePrint Basal patients was 49 of 140 (35Β %), comparable to the 34 of 92 pCR rate (37Β %) in IHC/FISH TN patients. CONCLUSIONS: BluePrint molecular subtyping reclassifies 22Β % (94/426) of tumors, reassigning more responsive patients to the HER2 and Basal categories while reassigning less responsive patients to the Luminal category. These findings suggest that compared with IHC/FISH, BluePrint more accurately identifies patients likely to respond (or not respond) to NCT
Interleukin-13 Promotes Susceptibility to Chlamydial Infection of the Respiratory and Genital Tracts
Chlamydiae are intracellular bacteria that commonly cause infections of the respiratory and genital tracts, which are major clinical problems. Infections are also linked to the aetiology of diseases such as asthma, emphysema and heart disease. The clinical management of infection is problematic and antibiotic resistance is emerging. Increased understanding of immune processes that are involved in both clearance and immunopathology of chlamydial infection is critical for the development of improved treatment strategies. Here, we show that IL-13 was produced in the lungs of mice rapidly after Chlamydia muridarum (Cmu) infection and promoted susceptibility to infection. Wild-type (WT) mice had increased disease severity, bacterial load and associated inflammation compared to IL-13 deficient (β/β) mice as early as 3 days post infection (p.i.). Intratracheal instillation of IL-13 enhanced bacterial load in IL-13β/β mice. There were no differences in early IFN-g and IL-10 expression between WT and IL-13β/β mice and depletion of CD4+ T cells did not affect infection in IL-13β/β mice. Collectively, these data demonstrate a lack of CD4+ T cell involvement and a novel role for IL-13 in innate responses to infection. We also showed that IL-13 deficiency increased macrophage uptake of Cmu in vitro and in vivo. Moreover, the depletion of IL-13 during infection of lung epithelial cells in vitro decreased the percentage of infected cells and reduced bacterial growth. Our results suggest that enhanced IL-13 responses in the airways, such as that found in asthmatics, may promote susceptibility to chlamydial lung infection. Importantly the role of IL-13 in regulating infection was not limited to the lung as we showed that IL-13 also promoted susceptibility to Cmu genital tract infection. Collectively our findings demonstrate that innate IL-13 release promotes infection that results in enhanced inflammation and have broad implications for the treatment of chlamydial infections and IL-13-associated diseases
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