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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
161

Investigating Novel Biological Mechanisms of Head and Neck Cancers

Lenarduzzi, Michelle 10 January 2014 (has links)
Despite improvements in treatment strategies for head and neck squamous cell carcinoma (HNSCC), clinical outcome has remained disappointing, with 5-year overall survival rates hovering around 40-50%, underscoring an urgent need to better understand the biological bases of this disease. We chose to address this challenge by studying the role of micro-RNAs (miRNAs), and iron in HNSCC. We performed global profiling on 51 primary HNSCC compared to 4 normal laryngeal epithelial tissues, and identified 38 differentially expressed miRNAs between cancer vs. normal patient tissues. Functional validation confirmed a tumour promoting phenotype for miR-106b and miR-375. Integrating these findings with global miR profiling of HNSCC revealed two significantly over expressed miRNAs in HNSCC cell lines and patient samples: miR-193b and miR-205. Knockdown of miR-205 and miR-193b in HNSCC cell lines significantly decreased cell proliferation and colony formation. Moreover, NF1 was identified as a target of miR-193b. Downstream targets of NF1 including active-RAS and p-ERK were also suppressed after miR-193b knockdown. Finally, HNSCC patients with high levels of miR-193b experienced a lower disease-free survival than patients with low miR-193b expression. The second approach we took to better understand the biology of HNSCC was to examine the involvement of iron in the disease. In a panel of HNSCC cell lines, hemochromatosis (HFE) was one of the most overexpressed genes involved in iron regulation. Knockdown of HFE in HNSCC cell lines significantly decreased intracellular iron levels, resulting in a significant decrease in HNSCC cell proliferation, DNA synthesis, and Wnt signalling. When iron was re-introduced back into the cell after HFE knockdown, these cellular changes were reversed, indicating that iron was mediating this phenotype. Concordantly, HNSCC cells treated with an iron chelator ciclopirox olamine (CPX) significantly reduced proliferation and clonogenic survival. Finally, patients with high HFE expression experienced a reduced survival compared to patients with low HFE expression, corroborating the oncogenic role of HFE in HNSCC. In summary, using two independent methods, we have identified two potential prognostic biomarkers for HNSCC, namely miR-193b and HFE. Characterization of these two molecules, exposed critically dysregulated pathways driving disease progression. Specifically, the miR-193b~NF1 axis uncovered a novel mechanism of RAS and p-ERK activation in HNSCC; similarly, HFE exposed a novel tumour promotion role of iron in this disease.
162

Investigating Novel Biological Mechanisms of Head and Neck Cancers

Lenarduzzi, Michelle 10 January 2014 (has links)
Despite improvements in treatment strategies for head and neck squamous cell carcinoma (HNSCC), clinical outcome has remained disappointing, with 5-year overall survival rates hovering around 40-50%, underscoring an urgent need to better understand the biological bases of this disease. We chose to address this challenge by studying the role of micro-RNAs (miRNAs), and iron in HNSCC. We performed global profiling on 51 primary HNSCC compared to 4 normal laryngeal epithelial tissues, and identified 38 differentially expressed miRNAs between cancer vs. normal patient tissues. Functional validation confirmed a tumour promoting phenotype for miR-106b and miR-375. Integrating these findings with global miR profiling of HNSCC revealed two significantly over expressed miRNAs in HNSCC cell lines and patient samples: miR-193b and miR-205. Knockdown of miR-205 and miR-193b in HNSCC cell lines significantly decreased cell proliferation and colony formation. Moreover, NF1 was identified as a target of miR-193b. Downstream targets of NF1 including active-RAS and p-ERK were also suppressed after miR-193b knockdown. Finally, HNSCC patients with high levels of miR-193b experienced a lower disease-free survival than patients with low miR-193b expression. The second approach we took to better understand the biology of HNSCC was to examine the involvement of iron in the disease. In a panel of HNSCC cell lines, hemochromatosis (HFE) was one of the most overexpressed genes involved in iron regulation. Knockdown of HFE in HNSCC cell lines significantly decreased intracellular iron levels, resulting in a significant decrease in HNSCC cell proliferation, DNA synthesis, and Wnt signalling. When iron was re-introduced back into the cell after HFE knockdown, these cellular changes were reversed, indicating that iron was mediating this phenotype. Concordantly, HNSCC cells treated with an iron chelator ciclopirox olamine (CPX) significantly reduced proliferation and clonogenic survival. Finally, patients with high HFE expression experienced a reduced survival compared to patients with low HFE expression, corroborating the oncogenic role of HFE in HNSCC. In summary, using two independent methods, we have identified two potential prognostic biomarkers for HNSCC, namely miR-193b and HFE. Characterization of these two molecules, exposed critically dysregulated pathways driving disease progression. Specifically, the miR-193b~NF1 axis uncovered a novel mechanism of RAS and p-ERK activation in HNSCC; similarly, HFE exposed a novel tumour promotion role of iron in this disease.
163

Lokal fortgeschrittene Kopf-Hals-Tumoren- Eine retrospektive, monoinstitutionale Studie zur Beurteilung der postoperativen Radiochemotherapie im klinischen Alltag

Georgi, Alexander 12 December 2013 (has links) (PDF)
Die vorliegende retrospektive Studie zur postoperativen Radiochemothera-pie bei fortgeschrittenen Kopf-Hals-Tumoren sollte die eigenen Ergebnisse mit den prospektiv-randomisierten Studien vergleichend darlegen und dabei den Nutzen einer Radiochemotherapie überprüfen. Insgesamt wurden 155 Patienten in der retrospektiven Analyse eingeschlossen. Die Überlebens- und Rezidivraten des Patientengutes konnten anlehnend zu den publizier-ten Studien reproduziert werden. Ein Vorteil der Radiochemotherapie in Bezug nehmend auf den posttherapeutischen Verlauf konnte hierbei nicht festgestellt werden. Es traten signifikant vermehrt höhergradige Akutne-benwirkungen nach Applizierung der simultanen, systemischen Therapie auf. Die Arbeit konnte zeigen, dass sich durch die Reduzierung der Gesamt-behandungszeit als auch des Intervalls zwischen Operation und Beginn der adjuvanten Therapie das Gesamtüberleben sowie die lokoregionäre Rezidiv-rate signifikant verbessern ließen. Insgesamt scheinen die Fernmetastasie-rungen und die lokoregionären Rezidive maßgebend für die immer noch un-befriedigenden Überlebensraten zu sein. Gegenstand weiterer Untersu-chungen sollte daher die Optimierung der prätherapeutischen Diagnostik sowie der adjuvanten Therapie sein.
164

Kan cancer innebära mer än lidande? : Patienters upplevelser av sjukdom, behandlingsrelaterade biverkningar och omvårdnad samt copingstrategier vid huvud- och halscancer / Can cancer mean more than suffering? : Patients´ experiences of illness, treatment related side effects and nursing as well as coping strategies when having head and neck cancer

Niklasson, Cornelia, Sarenmalm, Emelie January 2013 (has links)
Bakgrund: Cancer i huvud- och halsområdet är den sjätte vanligaste cancerdiagnosen i världen. Begreppet huvud- och halscancer innefattar läppcancer, cancer i näsa och bihålor, i munhåla och svalg, struphuvud, på stämbanden och i spottkörtlarna. De vanligaste behandlingsformerna är kirurgi, strålbehandling och cytostatikabehandling. Sjukdomen och behandlingen innebär ofta svåra fysiska, psykiska och sociala biverkningar för patienten. Detta ställer stora krav på sjuksköterskans kunskaper och färdigheter inom området och i omvårdnaden av dessa patienter. Syfte: Syftet är att beskriva hur patienter med huvud- och halscancer kan uppleva behandlingsrelaterade biverkningar och hur dessa kan hanteras. Metod: En litteraturöversikt där tio kvalitativa artiklar granskades. Resultat: Resultatet presenteras i tre övergripande teman som även innehåller underteman. De tre huvudteman är; Lidande och upplevelsen av behandlingsrelaterade biverkningar, Omvårdnadsrelaterade upplevelser samt Hopp och mening. Slutsats: Patienter med huvud- och halscancer upplever sin sjukdom och behandling på många olika sätt. Sjukdomen i sig innebär en mångfacetterad problematik med både fysiska, psykiska och sociala aspekter. Oavsett behandlingsform drabbas patienten av biverkningar av varierande grad. För att hantera dessa biverkningar använder sig patienter av olika strategier och vissa gynnsamma aspekter av sjukdom som exempelvis ny positiv livsåskådning kan påvisas. Klinisk betydelse: Genom att belysa vilka problemområden som upplevs som mest betungande kan sjuksköterskor lättare söka lindra dessa. De positiva strategier som beskrivs kan av sjuksköterskan användas för att stärka patientens möjlighet till egenvård. / Background: Head and neck cancer is the worlds´ sixth most common malignancy. Head and neck cancer includes cancer in the lip, nasal cavity and the paranasal sinuses, the oral cavity, in the pharynx and larynx, in the glottis and in the salivary glands. The most common used treatments are surgery, radiotherapy and chemotherapy. The disease and it´s treatment often result in severe physical, psychological and social side effects. Aim: The aim is to describe how patients with head and neck cancer can experience the treatment related side effects and how they are managed. Method: A literature review of ten qualitative articles. Results: Three primary themes were identified; Suffering and the experience of treatment related side effects, Experiences related to nursing and Hope and meaning. Conclusion: Patients with head and neck cancer experience their disease and treatment in many different ways. The cancer alone can bring multifaceted problems including physical, psychological and social aspects. The patient will experience side effects of varying degree irrespective of which treatment being used. Different coping strategies are being used to cope with these side effects and some patients even report positive aspects of the disease. Clinical importance: By highlighting which areas that are the most burdensome for patients the nurses can more easily alleviate these areas. The positive strategies that are described can be used by the nurse to improve the patients´ ability for self care.
165

The impact of plan complexity on the accuracy of VMAT for the treatment of head and neck cancer

Satherley, Thomas William Scott January 2015 (has links)
Purpose: At the Wellington Blood and Cancer Centre (WBCC), Volumetric Modulated Arc Therapy (VMAT) is used to treat a variety of head and neck (H&N) cancers. Presently, the complexity of plans is limited to ensure the accuracy of patient treatment within the range of the departmental experience. The complexity limitation is applied through use of a monitor unit (MU) constraint during plan optimisation. Plans of higher complexity can be obtained by loosening the MU constraint, and setting more stringent optimisation objectives on organs at risk (OAR) and target volumes (PTV). This could potentially yield higher quality treatment plans but may also degrade the accuracy of the TPS calculation or the plan delivery at the treatment machine. The aim of this study is to investigate the level of plan complexity that results in accurate treatment plan calculation and delivery, and quantify the corresponding gain in plan quality. Methods: Five previously treated H&N patients were selected for the study. Each patient’s clinical plan was used as the lowest complexity level and labelled C1. Subsequently, an approximate pareto-optimal plan (C3) was created that focused equally on sparing spinal cord, brain stem and parotid gland while maintaining, or improving on, the previously obtained target coverage. Next, a C2 plan was created such that the plan quality was in between C1 and C3. Plan quality of each complexity level was assessed in terms of OAR sparing and PTV coverage. The average leaf pair opening (LPO), critical leaf pair opening (%LPO<1cm) and mean leaf travel were used as plan complexity metrics. The calculation and delivery accuracy of each complexity level using Varian TrueBeam LINAC/Eclipse TPS was verified using time resolved point dose measurements (TRPD), EBT film measurements (Ashland Inc.) and ArcCheck measurements (Sun Nuclear Corp.). A comprehensive uncertainty analysis was carried out including a quantification of the measurement and delivery reproducibility. Results: Increasing plan complexity from C1 to C3 reduced the Spinal Cord D1cc, Brain Stem D1 and Parotid Gland Dmean up to 14.7 Gy, 7.1 Gy and 7.8 Gy, respectively. In addition, C3 plans improved the target coverage compared to C1 plans, with the PTV66 and PTV54 D98 increasing up to 1.0 Gy and 0.6 Gy, respectively. The verification measurements showed that the plan calculation and delivery for all complexity levels was well within clinical acceptance levels (Table 1). TRPD showed that VMAT dose delivery itself was repeatable within 0.1% (1 S.D.) over 10 consecutive deliveries for both C1 and C3 complexity levels. Discussion & Conclusions: This study has shown that increasing the plan complexity can provide significant dosimetric advantages for the treatment of H&N cancer. Verification measurement results indicated that this did not noticeably degrade the calculation and delivery accuracy of VMAT using a Varian TrueBeam LINAC and our Eclipse TPS beam model. H&N VMAT at the WBCC can now be developed further with greater confidence in the dosimetric accuracy of higher complexity plans.
166

Huvudhalscancer och livskvalitet : Patientens skattning av livskvalitet innan och efter strålbehandling / Head and neck cancer and quality of life : Patients assessment of quality of life before and after radiation therapy

Salgado Willner, Helen January 2014 (has links)
Introduction: Each year 1200-1300 patients are diagnosed with head neck cancer. Treatment that involves radiotherapy can cause severe side effects for example trismus that affects quality of life. Purpose: To study health-related quality of life in patients who have undergone radiation treatment for head and neck cancer and participated in a intervention group who received training intended to prevent trismus or in a control group who received standard treatment. Method: This is a prospective study in which data is collected from 66 patients participating in a randomized study aiming to evaluate a training program to prevent trismus. Thirty three participated in the intervention group and thirty three in the control group. Both patient groups assessed health related quality of life (HRQOL) with EORTC QLQ C30 and QLQ-H&amp;N35, at start and end of the radiation treatment, and at 3 and 6-months after completing radiation treatment. Results: There is no difference between the intervention and control groups regarding symptoms, functional status and global health, except for intake of nutritional supplements.  For both groups almost all scales measuring HRQOL deteriorated under the radiation treatment. However, 3 and 6 months after end of radiotherapy HRQOL had improved and had returned to the baseline values. The only exceptions were dry mouth, sticky saliva, problems with social eating, senses and physical ability. Conclusion: Radiation therapy for head and neck cancer affects patients HRQOL both in the short and long term. Medical staff needs strategies to manage patients ' functional and symptomatic deterioration throughout the treatment period and try to prevent or relieve the symptoms that may still remain several months after radiotherapy.
167

Självupplevd oral hälsa hos patienter som strålats mot huvud- och halscancer / Self-perceived oral health in patients radiated against head and neck cancer

Andersson, Rebecka, Smajli, Dorentina January 2014 (has links)
Syftet med studien var att belysa hur patienter som strålats mot huvud- och halscancer upplevde sin orala hälsa efter avslutad strålbehandling. Studien är kvalitativ och består av intervjuer med åtta informanter. Intervjuerna har utförts med hjälp av en intervjuguide. Intervjuerna spelades in på bandspelare och varade i ca 10-20 minuter. Intervjumaterialet har analyserats med en kvalitativ innehållsanalys. Resultatet av studien visade att majoriteten av informanterna upplevde sin orala hälsa negativt efter avslutad strålbehandling, dessa benämns i fysisk effekt och psykisk begräsning. Informanterna upplevde smärta samt muntorrhet efter avslutad strålbehandling. Resultatet visade även att nutritionsbegränsingar uppstod och att de var tvungna till att göra kostförändringar, även sväljning och tuggning försvårades. Informanterna upplevde generellt att det var jobbigt att äta i stora sammanhang då rädslan för att sätta maten i halsen förekom. Strålbehandlingen påverkade även informanterna psykiskt genom att de ofta var låga i humöret. Slutsatsen av studien visar att dessa patienter upplever smärta, har problem med att äta och påverkas psykiskt samt att de hämmas socialt. / The purpose of this study was to illustrate how patients radiated against head and neck cancer, experience their oral health after ending radiotherapy. The study is qualitative and considers interviews with eight informants. The interviews were conducted using an interview guide. The interviews were recorded on a tape recorder and lasted about 10-20 minutes. The interview data were then analysed using a qualitative content analysis. The results of this study show that a majority of the respondents experience their oral health negatively after ending radiotherapy; these are mentioned in physical effect and mental limitation. The informants experienced pain and dry mouth after completing radiotherapy. The results also showed that they had trouble eating, including swallowing and chewing difficult and that they were forced to make dietary changes. The informants experienced generally it was hard to eat at large surroundings because the fear of choking occurred. Radiotherapy had also affected the informants psychologically, as they often was in low mood. The conclusion of the study shows that these patients experience pain, have trouble eating and that they are affected psychologically as well as inhibited socially.
168

Die pharmakologische Beeinflussung des Hedgehog Signaltransduktionsweges in Kopf-Hals-Tumoren ex vivo

Stöhr, Matthäus 05 February 2015 (has links) (PDF)
Der Hedgehog Signaltransduktionsweg (HhP) ist in der Embryologie und für die Tumor-entstehung bedeutsam und kann durch den spezifischen Antagonisten Cyclopamin (Cyc) inhibiert werden. Simvastatin (Sim) kann die für den HhP essentielle Cholesterolsynthese blockieren. Die therapeutische Unterdrückung des HhP in Kopf-Hals-Plattenepithel-karzinomen (HNSCC) zu untersuchen erschien nach verschiedenen Literaturhinweisen lohnend. In den Experimenten, deren Ergebnisse bereits in Artikeln publiziert wurden, konnten antineoplastische Effekte von Cyc bzw. Sim allein und in Kombination mit den Leitlinientherapeutika Cisplatin (Cis) oder Docetaxel (DTX) an der epithelialen Zelllinie KB, den Kopf-Hals-Zelllinien FaDu und HN-5, sowie an primären HNSCC ex vivo nachgewiesen werden. Biopsien von 49 HNSCC wurden im FLAVINO-Assay mit Cyc bzw. Sim in steigenden Konzentrationen allein und kombiniert mit Cis oder DTX untersucht. In die Auswertung konnten gemäß den Einschlusskriterien (histopathologisch bestätigtes HNSCC und suffiziente Koloniebildung im FLAVINO-Assay) 18 HNSCC einbezogen werden. Bei den Voruntersuchungen führten sowohl Cyc als auch Sim zu einer signifikanten Zeit- und Dosis-abhängigen Reduktion der Lebensfähigkeit von KB, FaDu und HN-5. Ebenso unterdrückten sowohl Cyc als auch Sim die Koloniebildung epithelialer Zellen im FLAVINO-Assay hochsignifikant. Auch tolerierbare Cis- und DTX-Konzentrationen zeigten eine signifikante Wachstumshemmung. In der Analyse des Interaktionsmodus wurde in den untersuchten Kombinationen (Sim+Cis, Sim+DTX, Cyc+Cis und Cyc+DTX) in allen Fällen Additivität als prädominanter Interaktionstyp ermittelt. Die Ergebnisse dieser Arbeit weisen den HhP als potentielles Target in HNSCC aus. Potentere und human besser verträgliche HhP-Blocker sollten unsere Ergebnisse bestätigen und in klinischen Studien getestet werden. Auch die Wirksamkeit von Sim auf HNSCC sollte in prospektiven klinischen Studien weiter analysiert und bestätigt werden. Möglicherweise vermag Sim bzw. die HhP-Blockade zukünftig einen Beitrag zur Therapie von HNSCC im Rahmen multimodaler Therapiekonzepte zu leisten.
169

Cell Death of Human Oral Squamous Cell Carcinoma Cell Line Induced by Herpes Simplex Virus Thymidine Kinase Gene and Ganciclovir

Nishikawa, Masaya, Hayashi, Yasushi, Yamamoto, Noriyuki, Fukui, Takafumi, Fukuhara, Hirokazu, Mitsudo, Kenji, Tohnai, Iwai, Ueda, Minoru, Mizuno, Masaaki, Yoshida, Jun 11 1900 (has links)
No description available.
170

Investigation into the Dosimetric Effects of Abutting Multi-Leaf-Collimated Photon Fields with Extended Source-to-Surface Electron Fields

STEEL, Jared Gary January 2007 (has links)
This thesis reports on the findings of an investigation into the dosimetry resulting from the abutment of en face 6 MeV electron and 6 MV photon beams as applied to the clinical challenge of radiation therapy treatments to head and neck cancer sites. Particular concern is given to the use of multi-leaf collimator (MLC) technology for photon beam definition when abutted to extended source-to-surface (SSD) electron beams. We made dosimetric comparison between MLC and Cerrobend® shielding for use in an abutment situation. The effects of extending the SSD of the electron beam were also assessed. We checked the ability of a Pinnacle3 v7.6 treatment planning system (TPS) to correctly model the dosimetry resulting from this extended electron beam SSD. Volumetric simulations of composite dosimetry resulting in water were conducted in MATLAB® for variations of surface abutment gap, and photon beam shielding type and angle. Visualization Toolkit (VTK) script was developed to visualise the resulting dosimetry. The effect of extending the SSD of the electron beam increases the beam penumbra significantly, exacerbating the challenge of matching this field to a photon beam edge. Furthermore, the TPS was shown to inaccurately model the electron beam penumbra for the extended SSD conditions. The employment of MLC shielding provides for some advantages over Cerrobend® in terms of overall composite hotspot volumes and coldspot magnitudes, though introduces detrimental dosimetric inhomogeneities in the underlying volume. Distinctly, no combination of abutment gap and shielding variables resulted in dosimetry in the range of 90% to 110% at the depth of dmax for the beam energies considered here. We provided tabulated data across these variables to outline the trade-offs present, and aid clinical decisions regarding this challenging dosimetric

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