275 research outputs found

    The Cauchy problem for a class of two-dimensional nonlocal nonlinear wave equations governing anti-plane shear motions in elastic materials

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    This paper is concerned with the analysis of the Cauchy problem of a general class of two-dimensional nonlinear nonlocal wave equations governing anti-plane shear motions in nonlocal elasticity. The nonlocal nature of the problem is reflected by a convolution integral in the space variables. The Fourier transform of the convolution kernel is nonnegative and satisfies a certain growth condition at infinity. For initial data in L2L^{2} Sobolev spaces, conditions for global existence or finite time blow-up of the solutions of the Cauchy problem are established.Comment: 15 pages. "Section 6 The Anisotropic Case" added and minor changes. Accepted for publication in Nonlinearit

    Antioxidants and cancer therapy: A systematic review

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    A B S T R A C T Purpose Many patients with cancer take antioxidant nutritional supplements during cancer treatment to alleviate treatment toxicities and to improve long-term outcomes, but little is known about the efficacy and safety of antioxidant use during cancer treatment. We reviewed English-language manuscripts published in the biomedical literature, reporting the results of observational studies of antioxidant status and cancer outcomes and of intervention trials of antioxidants among patients receiving chemotherapy with or without radiation for various malignancies. Methods We searched the Medline database and the bibliographies of the retrieved manuscripts, reviews, and books on antioxidants and cancer. The retrieved studies are grouped by study design, malignancy, and end points. Results More than 100 citations were retrieved; 52 met our criteria, 31 were observational studies, and 21 were intervention trials. The studies varied in study design, timing of observation/intervention, intervention protocol, malignancy, and anticancer regimen. Conclusion These inconsistencies preclude a definitive conclusion as to the effect of chemotherapy on antioxidant status in patients undergoing anticancer therapy. However, our review suggests that total antioxidant status (measured by total radical antioxidant parameter) declines during cancer treatment. Adequately powered trials or observational studies among patients with a specific cancer diagnosis receiving a specific treatment regimen are needed to address patients' and physicians' concerns regarding these associations

    Relation of gallbladder function and Helicobacter pylori infection to gastric mucosa inflammation in patients with symptomatic cholecystolithiasis

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    Background. Inflammatory alterations of the gastric mucosa are commonly caused by Helicobacter pylori (Hp) infection in patients with symptomatic gallstone disease. However, the additional pathogenetic role of an impaired gallbladder function leading to an increased alkaline duodenogastric reflux is controversially discussed. Aim:To investigate the relation of gallbladder function and Hp infection to gastric mucosa inflammation in patients with symptomatic gallstones prior to cholecystectomy. Patients: Seventy-three patients with symptomatic gallstones were studied by endoscopy and Hp testing. Methods: Gastritis classification was performed according to the updated Sydney System and gallbladder function was determined by total lipid concentration of gallbladder bile collected during mainly laparoscopic cholecystectomy. Results: Fifteen patients revealed no, 39 patients mild, and 19 moderate to marked gastritis. No significant differences for bile salts, phospholipids, cholesterol, or total lipids in gallbladder bile were found between these three groups of patients. However, while only 1 out of 54 (< 2%) patients with mild or no gastritis was found histologically positive for Hp, this infection could be detected in 14 (74%) out of 19 patients with moderate to marked gastritis. Conclusion: Moderate to marked gastric mucosa inflammation in gallstone patients is mainly caused by Hp infection, whereas gallbladder function is not related to the degree of gastritis. Thus, an increased alkaline duodenogastric reflux in gallstone patients seems to be of limited pathophysiological relevance. Copyright (c) 2006 S. Karger AG, Basel

    Tear fluid biomarkers in ocular and systemic disease: potential use for predictive, preventive and personalised medicine

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    In the field of predictive, preventive and personalised medicine, researchers are keen to identify novel and reliable ways to predict and diagnose disease, as well as to monitor patient response to therapeutic agents. In the last decade alone, the sensitivity of profiling technologies has undergone huge improvements in detection sensitivity, thus allowing quantification of minute samples, for example body fluids that were previously difficult to assay. As a consequence, there has been a huge increase in tear fluid investigation, predominantly in the field of ocular surface disease. As tears are a more accessible and less complex body fluid (than serum or plasma) and sampling is much less invasive, research is starting to focus on how disease processes affect the proteomic, lipidomic and metabolomic composition of the tear film. By determining compositional changes to tear profiles, crucial pathways in disease progression may be identified, allowing for more predictive and personalised therapy of the individual. This article will provide an overview of the various putative tear fluid biomarkers that have been identified to date, ranging from ocular surface disease and retinopathies to cancer and multiple sclerosis. Putative tear fluid biomarkers of ocular disorders, as well as the more recent field of systemic disease biomarkers, will be shown

    Different perceptions of the burden of upper GI endoscopy: an empirical study in three patient groups

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    Background: Few studies have evaluated patients' perceived burden of cancer surveillance tests. Cancer screening and surveillance, however, require a large number of patients to undergo potentially burdensome tests with only some experiencing health gains from it. We investigated the determinants of patients' reported burden of upper gastrointestinal (GI) endoscopy by comparing data from three patient groups. Patients and methods: A total of 476 patients were included: 180 patients under regular surveillance for Barrett esophagus (BE), a premalignant disorder; 214 patients with non-specific upper GI symptoms (NS), and 82 patients recently diagnosed with upper GI cancer (CA). We assessed pain, discomfort and overall burden experienced during endoscopy, symptoms in the week afterwards and psychological distress over time (Hospital Anxiety and Depression scale and Impact of Event Scale). Results: Two-thirds (66%) of patients reported discomfort and overall burden of upper GI endoscopy. Only 23% reported any pain. BE patients reported significantly less discomfort, pain and overall burden than the other patients: those with NS reported more discomfort, CA patients more pain, and both more overall burden. These differences could be statistically explained by the number of previous endoscopies and whether sedation was provided or not, but not by patient characteristics. Conclusion: The perception of upper GI endoscopy varies by patient group, due to potential adaptation after multiple endoscopies and aspects of th

    Effect of dietary honey on intestinal microflora and toxicity of mycotoxins in mice

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    BACKGROUND: Bee honey is a functional food which has a unique composition, antimicrobial properties and bifidogenic effect. In order to assess whether honey can inhibit the toxic effect of mycotoxins, the present study was undertaken. METHODS: Production of biomass and toxins by Aspergillus parasiticus and Aspergillus ochraceus were followed in media without and with honey. Although aflatoxins and ochratoxin A. were administrated to male Swiss albino mice up to 1 μg and 10 ng/kg body weight/day respectively. The experimental animals were fed diets without our with 10% honey for two months. The changes in colonic probiotic bacteria, determintal colon enzyme glucuronidases, and genotoxicity were followed. RESULTS: Addition of 32% in its media increased the biomass of A parasiticus, while the biomass of A. ochraceus decreased and Ochratoxin A. was not produced. When the honey was added at the ratio of 32 and 48% in the medium. No relationship was found between mycelium weight and production of mycotoxins. Oral administration of aflatoxins (mixture of B(1), B(2), G(1) and G(2)) and Ochratoxin A. induced structural and numerical chromosomal aberrations in bone marrow and germ cells of male mice, whereas, honey treatment reduced the genotoxicity of mycotoxins. Also both toxins induced histopathological changes in liver and kidney. Feeding on diet supplemented with honey improved the histopathological changes in case of aflatoxin group, but not in the case of ochratoxin A. group (except of kidney in two cases). No significant differences were found in the activity of colon β-glucuronidase between group fed diet with or without honey. On the other hand, the colon bifido bacteria and lactobacilli counts were increased markedly in group receiving diet supplemented with honey. CONCLUSION: Substituting sugars with honey in processed food can inhibit the harmful and genotoxic effects of mycotoxins, and improve the gut microflora
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