134 research outputs found
Helicobacter pylori and epithelial mesenchymal transition in human gastric cancers: An update of the literature
Gastric cancer, a multifactorial disease, is considered one of the most common malignancies worldwide. In addition to genetic and environmental risk factors, infectious agents, such as Epstein-Barr virus (EBV) and Helicobacter pylori (H.pylori) contribute to the onset and development of gastric cancer. H. pylori is a type I carcinogen that colonizes the gastric epithelium of approximately 50% of the world's population, thus increasing the risk of gastric cancer development. On the other hand, epithelial mesenchymal transition (EMT) is a fundamental process crucial to embryogenic growth, wound healing, organ fibrosis and cancer progression. Several studies associate gastric pathogen infection of the epithelium with EMT initiation, provoking cancer metastasis in the gastric mucosa through various molecular signaling pathways. Additionally, EMT is implicated in the progression and development of H. pylori-associated gastric cancer. In this review, we recapitulate recent findings elucidating the association between H. pylori infection in EMT promotion leading to gastric cancer progression and metastasis.Open Access funding was provided by Qatar National Library.Scopu
The role of invariant natural killer T cells and lipids in the development of allergic sensitisation
Introduction
IgE-mediated food allergies are increasing in prevalence, currently affecting 2.6% of infants in the UK. However, the mechanisms underpinning the first phase of IgE-mediated allergy, allergic sensitisation, are still not clear. Recently, the potential involvement of lipids in allergic sensitisation has been proposed, with reports that they can activate invariant natural killer T (iNKT) cells, to secrete Th1 and Th2 cytokines. However, the existing research in this area is limited and predominantly use murine models. Thus, this research developed a human in vitro method to study the role of lipids and iNKT cells in a model of allergic sensitisation. This method was applied to peanut allergy, one of the most common food allergies in children and adults. Thus, the total lipid fraction from peanuts (peanut oil) was utilised with and without the lipophilic peanut allergen, Ara h 8, to examine any influence on iNKT cell cytokine production, comparing between peanut-allergic and non-allergic individuals.
Methods
Due to low abundance of iNKT cells in human peripheral blood, iNKT cells were expanded over 14 days by stimulation with the glycolipid, α-Galactosylceramide (α-GalCer), which is a potent activator of iNKT cells. Autologous dendritic cells (DCs) were generated from monocytes and stimulated with either peanut oil, Ara h 8, or both peanut oil and Ara h 8. The expanded iNKT cells were then immunomagnetically isolated and co-cultured with autologous DCs to allow lipid and/or allergen presentation to iNKT cells. This co-culture was first optimised using α-GalCer-pulsed DCs before applying to peanut oil and Ara h 8. Th1 and Th2 iNKT cell cytokine expression was then measured during iNKT-DC co-culture by flow cytometry.
Results
Flow cytometry staining of iNKT cells from peanut-allergic and non-allergic subject’s peripheral blood found a 5-fold higher iNKT cell population in peanut-allergic subjects compared to non-allergic subjects. The iNKT cells from both subject groups were then successfully expanded, with iNKT cell populations increasing by 133-fold in peanut-allergic subjects and 122-fold in non-allergic subjects after 14 days of culture with α-GalCer. A shift in iNKT cell phenotype to CD4+ iNKT cells was observed in both subject groups after expansion. Also, DCs were successfully generated at high purities from monocytes, and imaging flow cytometry found the immature DCs can internalise lipids and allergens. Finally, iNKT cell co-culture with α-GalCer-pulsed DCs showed increases in iNKT cell production of IFNγ-only and IFNγ+IL4+ after 5 hours, confirming this in vitro, human, cell-based assay is functional. However, when the method was applied to peanut allergy, utilising peanut oil and Ara h 8, the results showed peanut oil and/or Ara h 8 did not have an influence on cytokine production by iNKT cells.
Conclusion
Overall, this study establishes a human model system where allergen-associated lipids can be assessed to determine whether they enhance iNKT cell Th2 cytokine secretion, shifting towards a state of allergic sensitisation. However, peanut oil had no effect on iNKT cell cytokine production. Future research could focus on a specific lipid class from peanut oil, such as the fatty acid oleic acid, to investigate any influence on iNKT cell cytokine production
Clinical relevance of virulence genes in Helicobacter pylori isolates recovered from adult dyspeptic patients in Turkey
Purpose: Bacterial virulence factors play a major role in the pathogenesis of Helicobacter pylori infection. The aims of this study were to evaluate virulence genes in H. pylori isolates and to compare the presence of these genes and associated clinical pathologies. Methods: A total of 148 H. pylori isolates, recovered from adult dyspeptic patients, were used. The patients, from whom the isolates were obtained, were assigned to two groups by their endoscopic findings, which manifested as chronic gastritis or peptic ulcer. The presence of gastric atrophy and intestinal metaplasia was recorded for each patient, based on histopathological examination. Analyses of the virulence genes were performed by the polymerase chain reaction technique. Results: The patients had a mean age of 47 ?± ?15 years and 86 (58%) of them were female. Based on endoscopic examination, 103 (69.6%) patients were diagnosed with chronic gastritis and 45 (30.4%) with peptic ulcer. Histopathological examination revealed intestinal metaplasia in 30 (20%) patients and gastric atrophy in 12 (8%) patients. The prevalence rates of cagA, cagE, iceA1, iceA2, and babA2 were determined to be 87%, 74%, 58%, 26%, and 95%, respectively. The most prevalent vacA alleles were s1/s1a (82%/97%) and the least prevalent allele was s2 (20%). A new vacA genotype (s1as1bs1c) was detected, for the first time, in 18 (12%) isolates. No significant difference was found between the patient groups with chronic gastritis and peptic ulcer for the prevalences of the virulence genes (p ?> ?0.05). Furthermore, intestinal metaplasia and gastric atrophy showed no significant correlation with the virulence genes (p ?> ?0.05). Conclusions: It is thoughted that H. pylori isolates with predominant cagA, cagE, VacA (s1, s1a), and babA2 virulence genes are associated with gastroduodenal diseases. However, there is no correlation between gastric premalignant lesions and virulence genes. © 2022 Indian Association of Medical Microbiologist
Text-image synergy for multimodal retrieval and annotation
Text and images are the two most common data modalities found on the Internet. Understanding the synergy between text and images, that is, seamlessly analyzing information from these modalities may be trivial for humans, but is challenging for software systems. In this dissertation we study problems where deciphering text-image synergy is crucial for finding solutions. We propose methods and ideas that establish semantic connections between text and images in multimodal contents, and empirically show their effectiveness in four interconnected problems: Image Retrieval, Image Tag Refinement, Image-Text Alignment, and Image Captioning. Our promising results and observations open up interesting scopes for future research involving text-image data understanding.Text and images are the two most common data modalities found on the Internet. Understanding the synergy between text and images, that is, seamlessly analyzing information from these modalities may be trivial for humans, but is challenging for software systems. In this dissertation we study problems where deciphering text-image synergy is crucial for finding solutions. We propose methods and ideas that establish semantic connections between text and images in multimodal contents, and empirically show their effectiveness in four interconnected problems: Image Retrieval, Image Tag Refinement, Image-Text Alignment, and Image Captioning. Our promising results and observations open up interesting scopes for future research involving text-image data understanding.Text und Bild sind die beiden häufigsten Arten von Inhalten im Internet. Während es für Menschen einfach ist, gerade aus dem Zusammenspiel von Text- und Bildinhalten Informationen zu erfassen, stellt diese kombinierte Darstellung von Inhalten Softwaresysteme vor große Herausforderungen. In dieser Dissertation werden Probleme studiert, für deren Lösung das Verständnis des Zusammenspiels von Text- und Bildinhalten wesentlich ist. Es werden Methoden und Vorschläge präsentiert und empirisch bewertet, die semantische Verbindungen zwischen Text und Bild in multimodalen Daten herstellen. Wir stellen in dieser Dissertation vier miteinander verbundene Text- und Bildprobleme vor: • Bildersuche. Ob Bilder anhand von textbasierten Suchanfragen gefunden werden, hängt stark davon ab, ob der Text in der Nähe des Bildes mit dem der Anfrage übereinstimmt. Bilder ohne textuellen Kontext, oder sogar mit thematisch passendem Kontext, aber ohne direkte Übereinstimmungen der vorhandenen Schlagworte zur Suchanfrage, können häufig nicht gefunden werden. Zur Abhilfe schlagen wir vor, drei Arten von Informationen in Kombination zu nutzen: visuelle Informationen (in Form von automatisch generierten Bildbeschreibungen), textuelle Informationen (Stichworte aus vorangegangenen Suchanfragen), und Alltagswissen. • Verbesserte Bildbeschreibungen. Bei der Objekterkennung durch Computer Vision kommt es des Öfteren zu Fehldetektionen und Inkohärenzen. Die korrekte Identifikation von Bildinhalten ist jedoch eine wichtige Voraussetzung für die Suche nach Bildern mittels textueller Suchanfragen. Um die Fehleranfälligkeit bei der Objekterkennung zu minimieren, schlagen wir vor Alltagswissen einzubeziehen. Durch zusätzliche Bild-Annotationen, welche sich durch den gesunden Menschenverstand als thematisch passend erweisen, können viele fehlerhafte und zusammenhanglose Erkennungen vermieden werden. • Bild-Text Platzierung. Auf Internetseiten mit Text- und Bildinhalten (wie Nachrichtenseiten, Blogbeiträge, Artikel in sozialen Medien) werden Bilder in der Regel an semantisch sinnvollen Positionen im Textfluss platziert. Wir nutzen dies um ein Framework vorzuschlagen, in dem relevante Bilder ausgesucht werden und mit den passenden Abschnitten eines Textes assoziiert werden. • Bildunterschriften. Bilder, die als Teil von multimodalen Inhalten zur Verbesserung der Lesbarkeit von Texten dienen, haben typischerweise Bildunterschriften, die zum Kontext des umgebenden Texts passen. Wir schlagen vor, den Kontext beim automatischen Generieren von Bildunterschriften ebenfalls einzubeziehen. Üblicherweise werden hierfür die Bilder allein analysiert. Wir stellen die kontextbezogene Bildunterschriftengenerierung vor. Unsere vielversprechenden Beobachtungen und Ergebnisse eröffnen interessante Möglichkeiten für weitergehende Forschung zur computergestützten Erfassung des Zusammenspiels von Text- und Bildinhalten
Understanding grand and petty corruption: A case study of Slovak health care
INTRODUCTION: As one of the more elusive social phenomena, corruption is notoriously difficult to investigate or measure, due to its clandestine nature. Within this work, corruption is conceptualised and addressed by focusing on sociological elements of cultural pressure, learnt behaviour, historical perspectives, and Central European regional idiosyncrasies of post-communist practices, all impacting on modern corrupt practices.
METHODS: This thesis examines the applicability of the ‘grand’ and ‘petty’ corruption distinction to a real-life understanding of corruption by qualitatively analysing the data collected during fieldwork in Slovakia. The main research question addressed reads as follows: To what extent is the theoretical difference between grand and petty corruption reflected in the real-life understanding of corruption in Slovakia’s health care? Interviews and focus groups are analysed in the work using thematic and textual analysis, and utilising the NVivo12 software to identify trends and commonalities in regard to views of the prevalence, mechanisms, and barriers associated with corruption. The empirical part of the work is centred around the interpretivist approach to data analysis, emphasising the relevance and indispensability of the participants’ natural narrative in their real-life understanding of corruption, shaped by experience, rather than theory.
RESULTS: The research demonstrates the shortcomings in corruption scholarship so far with regards to classification, measurement, and presentation of data. The existing bias towards economic and financial angles of corruption investigation is mitigated by applying a qualitative research design, focused on language and understanding. The research identified cultural nuances of acceptance of gift-giving, and the prevalence of corruption brokerage in everyday corruption in Slovakia. The roles of trust, fear, communist legacies, and networks in day-to-day corruption instigation, and deterrence in corruption reporting, are presented as instrumental in promoting corrupt practice in the Slovak health care sector.
CONCLUSION: The thesis concludes that the labels of grand and petty corruption apply to real-life understanding only marginally and that all theoretical terminology relating to corruption disaggregation should be verified in similar research designs, with emphasis on qualitative data analysis. Such analysis is upheld as able to encompass complexity of corruption understanding, inclusive of regional specificities and circumstances. Specific recommendations on incorporating real-life language and understanding are made regarding policy and legislation changes in Slovakia, as well as transparency of language within healthcare insurance re-drafting, and healthcare professional oversight
Virulence Markers, Genotypic versus Phenotypic Resistance and New Treatment Strategies in <em>Helicobacter pylori</em> Infection
This chapter aims at studying the microbial virulence determinants and markers of Helicobacter pylori (Hp), the molecular diagnostic of Hp, the growing antibiotic resistance with the related problem of heteroresistance, the genotypic resistance to antimicrobials compared with the phenotypic methods and the new treatment strategies for Hp eradication also evaluating new antimicrobial agents (furazolidone, vonoprazan). The virulence markers cover an important area in Hp pathology due to the correlation between these and the different diseases. The Hp molecuar diagnosis is fast, accurate and reliable over the traditional methods that are expensive and time- consuming. Therapy regimens used over the past decade are declining in efficacy being the Hp treatment bedevilled by drug-resistant strains. New treatment strategies are under study worldwide. The determination of the genetic resistance to antibiotics is very useful when used directly on gastric biopsies for prediction of antibiotics ineffectiveness or for addressing changes in previous treatments
Dyspepsia
This textbook is specifically written for clinicians involved in managing patients with dyspepsia. It is a practical guide with up-to-date suggestions on evaluation, diagnosis, and management from experts from around the world. Each chapter is a succinct review of current topics that play a role in the pathogenesis and management of this disorder. Special populations such as pediatrics, those with cardiovascular disease and womens health are specifically examined
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