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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.
231

DNA Damage Response of Normal Epidermis in the Clinical Setting of Fractionated Radiotherapy : Evidence of a preserved low-dose hypersensitivity response

Qvarnström, Fredrik January 2009 (has links)
Investigations of DNA damage response (DDR) mechanisms in normal tissues have implications for both cancer prevention and treatments. The accumulating knowledge about protein function and molecular markers makes it possible to directly trace and interpret cellular DDR in a tissue context. Using immunohistochemical techniques and digital image analysis, we have examined several principal DDR events in epidermis from patients undergoing fractionated radiotherapy. Acquiring biopsies from different regions of the skin provides the possibility to determine in vivo dose response at clinically relevant dose levels throughout the treatment. A crucial event in cellular DDR is the repair of DNA double strand breaks (DSBs). These serious lesions can be directly visualised in cells by detecting foci forming markers such as γH2AX and 53BP1. Our results reveal that DSB-signalling foci can be detected and quantified in paraffin-embedded tissues. More importantly, epidermal DSB foci dose response reveals hypersensitivity, detected as elevated foci levels per dose unit, for doses below ~0.3Gy. The low-dose hypersensitive dose response is observed throughout the treatment course and also in between fractions: at 30 minutes, 3 hours and 24 hours following delivered fractions. The dose response at 24 hours further reveals that foci levels do not return to background levels between fractions. Furthermore, a low-dose hypersensitive dose response is also observed for these persistent foci. Investigations of end points further downstream in the DDR pathways confirmed that the low-dose hypersensitivity was preserved for: the checkpoint regulating p21 kinase inhibitor; mitosis suppression; apoptosis induction and basal keratinocyte reduction. Our results reveal preserved low-dose hypersensitivity both early and late in the DDR pathways. A possible link between the dose-response relationships is therefore suggested. The preserved low-dose hypersensitivity is a cause for re-evaluation of the risks associated with low-dose exposure and has implications for cancer treatments, diagnostics and radiation protection.
232

Att leva med lokaliserad prostatacancer : "oss män emellan"

Hedestig, Oliver January 2006 (has links)
The purpose of this thesis is to explore how men experience living with localized prostate cancer. It includes four substudies carried out between 1997 and 2005. To gather data, the men were interviewed at home and the interviews were recorded. The men (n=27; ages 60-70) who participated in the substudies had a PSA ≤10 ng/ml at the time of diagnosis, and had what is known as low-risk prostate cancer. Seven of the men chose to “wait and see” how the disease would progress after receiving the diagnosis. Twenty men chose curative treatment (10 men external radiation therapy, 10 men radical surgery). The interviews were analyzed using a phenomenological hermeneutical method inspired by the philosophy of Paul Ricoeur, and qualitative content analysis. Men who live with localized prostate cancer perceive the disease as life-threatening, unpredictable, and without early symptoms, which creates a sense of uncertainty, worry, anxiety, despair, and fear of death. Men primarily share perceptions of the disease and treatment with their wives and relatives, as well as with other men in the same situation. They avoid talking about their illness, and keep their innermost thoughts about their disease, prognosis, and the future to themselves. The choice to share their thoughts and feelings only sparingly with others is related in part to the perceived stigmatization of the diagnosis, as well as to consideration for friends and family. The men report that external radiation therapy and radical surgery have negative side effects such as erectile dysfunction, urinary incontinence, and intestinal leakage. They describe the side effects as socially isolating; for example, urinary leakage can require a change of incontinence pads and clothing, and they feel that they smell bad. Men with erectile dysfunction describe themselves as maimed, and their sex lives have changed or disappeared. They report a change in their self-esteem and identity as men and they long for life as it was before the diagnosis, when they felt they had control over their bodily functions. A few men describe a sense of being literally and figuratively “exposed” when they are undressed for examinations or participate in discussions with female doctors and nurses about their erectile dysfunction. They do not describe this perception in the same way with respect to contact with male personnel. In the new situation after treatment, men try to regain a perceived sense of control in their daily lives, over the disease and the effects of treatment. They experience a sense of control over the disease through regular PSA tests; the implications of regular PSA tests can be interpreted as a life preserver in an uncertain world, considering that at the time they were diagnosed they had no symptoms and only had a PSA elevation. The PSA is important for this sense of control, and each PSA test is preceded by tense expectation. The PSA level is described as a reliable expression of the medical condition. The men cannot trust that their own perception of feeling healthy means that the disease is under control. Low and stable PSA levels over a long period of time give a sense of safety, security, and control over the situation. If the PSA climbs, the men feel that despite everything, they have caught it in time for further treatment. Discussions with other men with prostate cancer are also described as a way of having control over the situation. The men's endeavor to reconcile themselves to the new situation can be understood as a process, where they describe various strategies which can be used to forget the “cancer perspective” and achieve a perception of safety and security. Reconciliation with a new situation can be interpreted as a reorientation after the trauma of the cancer diagnosis. The study results show that the men are restrained in communicating their needs to others, which can be interpreted as their having a greater need for support and information than indicated by their signals. Having an internal image of what a man should be like can be an obstacle to showing these needs.
233

Angiogenesis in human renal cell carcinoma : hypoxia, vascularity and prognosis

Sandlund, Johanna January 2007 (has links)
Background: Angiogenesis is recognised as a critical step in tumour progression. The angiogenic switch is activated by various trigger signals, such as hypoxia, low pH, and genetic mutations. Renal cell carcinoma (RCC) is often an aggressive tumour, and advanced disease has limited treatment options and bad prognosis. This study was focused on markers of angiogenesis in RCC: endoglin (CD105) and CD31 assessing microvessel density (MVD), and carbonic anhydrase (CA) IX and hypoxia-inducible factor (HIF)-2α expressed at hypoxia. Upregulation of HIF is also associated with inactivation of the von Hippel-Lindau (VHL) tumour suppressor gene, which is common in conventional/clear cell (c)RCC. Method: A tumour bank containing 308 tumours from patients operated 1982-2003 was used. The tumours were well characterised regarding tumour type, TNM stage, nuclear grade, tumour size, and patient survival. The tumours were prepared in tissue microarrays and fresh frozen in whole sections. To analyse the expression of endoglin, CD31, CA IX, and HIF-2α mRNA, immunohistochemistry and real-time PCR were used. Results: There was a higher endoglin expression in cRCC than in papillary (p)RCC and chromophobe (ch)RCC, and a higher CD31 expression in cRCC than in pRCC. MVD correlated inversely to TNM stage and nuclear grade in cRCC. There was also an inverse correlation between tumour diameter and CD31 expression in cRCCs. Patients with cRCC with high MVD had a more favourable prognosis than patients with lower MVD. Endoglin and CD31 were not independent prognostic factors. The CA IX expression was higher in cRCC than in pRCC and chRCC. Patients with cRCC expressing low CA IX had a significantly less favourable prognosis compared with those with higher expression. CA IX is an independent prognostic factor. There was a higher HIF-2α mRNA expression in cRCC than in pRCC and chRCC. In cRCC, there was a significant inverse correlation between HIF-2α mRNA expression, and TNM stage and nuclear grade. There was also an inverse correlation between HIF-2α mRNA expression and tumour size among patients with cRCC. HIF-2α was not an independent prognostic factor. Conclusion: In these studies, the factors related to hypoxia and vascularity were all inversely correlated to tumour aggressiveness in cRCC. MVD, CA IX, and HIF-2α expression were also higher in cRCC than in pRCC and chRCC. The relationship between angiogenesis, vascularity, and hypoxia is ambiguous. A line of reasoning including mutations increasing angiogenesis in advanced disease may also be applied to RCC. Measurements of individual angiogenic factors seem to provide prognostic information, and can potentially be combined in patient monitoring and treatment.
234

Radiolabeled acetate PET in oncology imaging : studies on head and neck cancer, prostate cancer and normal distribution

Sun, Aijun January 2010 (has links)
The use of positron emission tomography (PET) for imaging in oncology has grown rapidly in recent years. 2-[18F]-fluorodeoxyglucose (FDG) is the most common tracer of PET, although drawbacks exist. Radiolabeled 1-[11C]-acetate (C-AC) is a simple probe for evaluation of perfusion, anabolism (lipogenesis) and catabolism (oxidative metabolism) in all living tissues. This study explored the potential of AC PET in head and neck cancer, benign and malignant lymph nodes in prostate cancer and normal distribution.  In head and neck cancer, C-AC PET detected more primaries and lymph node metastases than FDG PET. The mean primary tumor volumes delineated by C-AC was 51% larger than that of FDG before radiotherapy (RT). Both FDG and C-AC PET tumor volumes must be carefully validated before used in clinical routine. Baseline tumor clearance rate (kmono) was higher in complete responders (CR) than that in partial responders (PR). kmono tended to correlate inversely with FDG SUV at baseline. Radiosensitive tumors might rely predominantly on oxidative metabolism for their biogenetic needs. kmono increased in PR during RT. The potential reversibility of impaired kmono in radioresistant tumors imply that treatment targeting the intermediary metabolism might improve the outcome. Tumor relative perfusion index (rF) and kmono were coupled in CR throughout the RT, but not in PR. Dynamic C-AC PET provides a new non-invasive method to simultaneously evaluate the tumor oxidative metabolism and perfusion which link the RT response in patients by a single tracer injection. In prostate cancer, elevated C-AC accumulation is common in benign inguinal lymph nodes, probably due to increased lipogenesis rather than lymphatic drainage. CT Hounsfield unit of benign nodes was lower than that of metastases, suggesting that density measurement using CT might improve the specificity of nodal staging of prostate cancer. A novel tracer 2-[18F]-fluoroacetate (F-AC) was synthesized and used for dynamic PET-CT imaging in animals. Compared with C-AC PET-CT, F-AC showed prolonged blood retention, no detectable trapping in myocardium and salivary glands, rapid excretion from liver to bile and urine and de-fluorination resulting in intensive skeletal activity. F-AC does not mimic the normal physiologic path of C-AC and appears to be of little use for assessment of perfusion, intermediary metabolism or lipogenesis.
235

Molecular Radionuclide Imaging Using Site-specifically Labelled Recombinant Affibody Molecules : Preparation and Preclinical Evaluation

Ahlgren, Sara January 2010 (has links)
Radionuclide molecular imaging is an emerging multidisciplinary technique that is used in modern medicine to visualise diseases at cellular and molecular levels. This thesis is based on five papers (I-V) and focuses on the development of site-specific radiolabelled recombinant anti-HER2 Affibody molecules and preclinical evaluations in vitro and in vivo of the labelled conjugates. This work is part of a preclinical development of an Affibody molecule-based tracer for molecular imaging of HER2 expressing tumours. Papers I and II report the evaluation of the Affibody molecule ZHER2:2395-C, site-specifically labelled with the radiometals 111In (for SPECT) and 57Co (as a surrogate for 55Co, suitable for PET applications) using a thiol reactive DOTA derivative as a chelator. Both conjugates demonstrated very suitable biodistribution properties, enabling high contrast imaging just a few hours after injection. Papers III and IV report the development and optimization of a technique for site-specific labelling of ZHER2:2395-C with 99mTc using an N3S chelating peptide sequence. 99mTc-ZHER2:2395-C demonstrated high and specific tumour uptake and rapid clearance of non-bound tracer from the blood, resulting in high tumour-to-non-tumour ratios shortly after injection, enabling high contrast imaging. In addition, in the study described in paper IV, freeze-dried kits previously developed for 99mTc-labelling were optimised, resulting in the development of a kit in which all the reagents and protein needed for labelling of ZHER2:2395-C with 99mTc were contained in a single vial. Paper V reports the evaluation of an anti-HER2 Affibody molecule, ABY-025, with a fundamentally re-engineered scaffold. Despite the profound re-engineering, the biodistribution pattern of 111In-ABY-025 was very similar to that of two variants of the parental molecule. It seems reasonable to believe that these results will also be applicable to Affibody molecules towards other targets. Hopefully, this work will also be helpful in the development of other small proteinaceous tracers.
236

Oncolytic Adenovirus Therapy of Neuroendocrine Tumors

Leja, Justyna January 2011 (has links)
Neuroendocrine tumors (NETs), originally described as carcinoids, represent a rare and heterogeneous group of neoplasms associated with intensive secretion of hormones, bioactive peptides and amines. Most of the patients are diagnosed at a late stage of disease, often with liver metastases. Surgery remains the main treatment to control metastatic disease, but is not curative. Oncolytic virotherapy represents a promising approach to treat cancer and different strategies have been exploited to restrict viral replication to tumor cells. We developed an oncolytic adenovirus based on serotype 5, Ad5[CgA-E1A], where the chromogranin A (CgA) promoter controls expression of the E1A gene and thereby virus replication. We found that Ad5[CgA-E1A], selectively replicates in NET cells and it is able to suppress fast-growing human BON carcinoid tumors in nude mice. The activity of Ad5[CgA-E1A] was not completely blocked in liver cells. We further repressed virus replication in hepatocytes by targeting E1A with miR122, an miRNA specifically expressed in the liver. miRNAs bind to mRNA and induce its cleavage or translational blockage. By insertion of tandem repeats of miR122 target sequences in 3’UTR of E1A gene, we observed reduced E1A protein expression and replication arrest in miR122 expressing liver cells. The oncolytic potency of the miR122-targeted virus was not affected in NET cells. Since some NET and neuroblastoma cells express high levels of somatostatin receptors (SSTRs), we introduced in the virus fiber knob cyclic peptides, which contain four amino acids (FWKT) and mimic the binding site of somatostatin for SSTRs. The FWKT-modified Ad5 transduces midgut carcinoid cells from liver metastases about 3-4 times better than non-modified Ad5. Moreover, FWKT-modified Ad5 overcomes neutralization in an ex vivo human blood loop model to a greater extent than Ad5, indicating that the fiber knob modification may prolong the systemic circulation time. NETs represent a huge therapeutic challenge and novel diagnostic markers are needed for early detection and effective treatment of NETs. We have profiled primary tumors and liver metastases of ileocaceal NETs, using Affymetrix microarrays and advanced bioinformatics. We have identified six novel marker genes and show high similarity between primary lesions and liver metastases transcriptome by hierarchical clustering analysis.
237

Oesophageal Cancer – Novel Targets for Therapy : With focus on Hsp90, EGFR, LRIG, microtubule and telomerase

Wu, Xuping January 2011 (has links)
Oesophageal cancer is a malignant and aggressive disease with very poor survival. The aim of this thesis was to evaluate novel therapeutic targets in oesophageal cancer. In paper I, Hsp90 was expressed in all 81 oesophageal cancer tissues and also in nine oesophageal cancer cell lines. A specific Hsp90 inhibitor, 17-AAG, could efficiently inhibit cell proliferation, cell survival and sensitise oesophageal cancer cells to gamma photon irradiation. By inhibition of Hsp90 using 17-AAG, EGFR- and IGF-1R-mediated signalling was downregulated. In paper II, tumour samples from 80 oesophageal cancer patients were investigated for the expression of EGFR and LRIG1-3. Based on a total score of intensity and expression fraction a trend towards survival differences was found for LRIG2 (p=0.18) and EGFR (p=0.09). Correlation analysis revealed a correlation between expression of EGFR and LRIG3 (p=0.0007). Significant correlations were found between LRIG1 mRNA expression levels and sensitivity to cisplatin (r = –0.74), docetaxel (r = –0.69), and vinorelbine (r = –0.82). In paper III, microtubule targeting drugs podophyllotoxin (PPT), vincristine and docetaxel inhibited survival and proliferation of oesophageal cancer cells. Unexpectedly, experiments showed that microtubule destabilising agents inhibited EGFR phosphorylation and signalling. A tyrosine phosphatase inhibitor, sodium orthovanadate, was able to reverse the EGFR dephosphorylation. In paper IV, imetelstat, a telomerase antagonist, inhibited telomerase activity, colony formation ability and decreased proliferation of oesophageal cancer cells. Inhibition of telomerase activity by imetelstat led to an increase of 53BP1 foci indicating induction of DSBs. Furthermore, the fraction and size of radiation-induced 53BP1 foci were increased by imetelstat pre-treatment. In conclusion, Hsp90 and telomerase represent potential therapeutic targets in oesophageal cancer. And, the implication of EGFR and LRIG as prognostic factors is limited. Furthermore, disruption of the microtubule network may activate a protein tyrosine phosphatase that can regulate EGFR phosphorylation.
238

Robust optimization of radiotherapy treatment plans considering time structures of the delivery

Orvehed Hiltunen, Erik January 2018 (has links)
Cancer is the second largest mortal disease in Sweden, and high efforts are made to develop the treatment of cancer. One of the main treatment methods is radiotherapy, which uses ionizing radiation to damage the cancerous cells. This has the chance of stopping the cell reproduction, and the goal is to reduce the tumor and stop the tumor growth. The most common forms of radiotherapy uses external beams to irradiate the tumor. In intensity modulated radiotherapy, IMRT, the beam fluences are optimized to give a highly conformal dose, i.e. a dose distribution which is restricted to the tumor and has low dose values outside of the tumor. A conformal dose is necessary to spare healthy tissue and sensitive organs, and thus keep the side-effects of the treatment at an acceptable level. The optimized beam shapes are created using a multileaf collimator, MLC. Finding the leaf positions and dose levels is formulated as a problem in the framework of mathematical optimization. Currently, one of the limitations in delivering conformal dose is due to patient movement during the treatment. In IMRT, the beams are delivered by consecutive segments, and the exact pairing of the segments with the patient position will have an impact on the delivered dose. This is called the interplay effect, and can cause both underdosage of the tumor and overdosage of the surrounding tissue. There are methods of mitigating the interplay effect. For example, the beam could be restricted to a single phase of the motion by repeatedly turning it on and off. This is known as gating. However, gating and many other interplay mitigation techniques lead to prolonged treatment times, which decreases the clinical throughput, causes higher patient discomfort and gives higher uncertainties in the delivered dose. This makes it desirable to find methods which avoid prolonged treatment times, while still giving highly conformal doses. Ideally, the best method would be to have a beam which follows any target movement. This idea is known as target tracking. In this thesis, an optimization method is suggested which includes the interplay effect in the treatment optimization. Two main treatment strategies are proposed. The method which is simplest to implement clinically is to create plans which are robust against uncertainties in the times for the patient motion. The resulting doses are found to give acceptable target covering where similar, conventional plans give a significant target underdose. To further increase the conformality of the doses, a non-robust method paired with gating technology is suggested. This method can effectively be seen as a target tracking method, and has the possibility to give highly conformal doses under acceptable treatment times.
239

Analysis of tumour infiltrating leukocytes in colon cancer carcinoma in a syngeneic rat model

Borgström, Annelie January 2010 (has links)
Tumour immunity is a balance between immune mediators that promote tumor progression versus mediators that promote tumor rejection. Infiltrating lymphocytes in human colorectal cancer tissues are independent prognostic factors for a better survival and a high number of cytotoxic CD8+ T-cells have been associated with a better prognosis in terms of a longer and disease free survival for the patient. In our syngeneic rat model we induce colon carcinoma subperitoneally by injecting a colon cancer cell line BN7005, a cell line expressing the epitope (Lewis Y) for the BR96 antibody. Tumours are dissected out and treated with different fixatives and then either frozen, snap-frozen or embedded in paraffin followed by sectioning. Immunohistochemistry using monoclonal antibodies against the tumour infiltrating leukocytes was performed on the tissue. The results were seen as an infiltration of different leukocytes in the tumours.
240

Datorbaserad rapportering av biverkningar och symptom vid cytostatikabehandlad avancerad bröstcancer

Terning, Fredrik, Ahl, Anna, Söderström, Sofie January 2009 (has links)
Syftet är att beskriva symtom och biverkningar som kvinnor med avancerad bröstcancer och cytostatikabehandling rapporterat i ett datoriserat rapporteringssystem före läkarbesök. Undersöka tillfredsställelsen med detta system; se om det finns en skillnad mellan äldre och yngre; undersöka kvinnornas uppfattning om vad som kan förbättras i uppföljningen av symtom/biverkningar samt stödet från läkare. Detta är en kvantitativ, deskriptiv tvärsnittsstudie baserat på rapporteringssystemets databas samt enkätundersökning.   Biverkningarna trötthet, smärta och nervpåverkan rapporterades mest frekvent. Tidsåtgången för rapportering ansågs utav de flesta vara kort eller mycket kort och formuläret upplevdes av majoriteten vara ganska lätt till mycket lätt att använda oberoende av datorvana. Läkaren ansågs från hög grad till mycket hög grad vara ett stöd i att hantera symtom och biverkningar av två tredjedelar av respondenterna. Hälften ansåg att rapporterade biverkningar och symtom uppmärksammades av läkaren i hög grad till mycket hög grad.   Undersökningen bekräftar det tidigare forskning visat om datoriserade rapporteringssystem i vården, att de är funktionella oavsett ålder samt att intresse finns för att använda dessa i större utsträckning. På grund av litet urval och relativt stort bortfall i enkätstudien kan dock inga direkta slutsatser dras men undersökningen antyder att behov finns att vidareutveckla rapporteringssystemet. / The aim of the study is to describe symptoms and side effects that women with advanced breast cancer and chemotherapy reported in an adverse drug reporting system before seeing their oncologist; examine the satisfaction with this system; if there are any differences between older and younger women; the women’s opinion of what improvements could be done in the follow-up of the symptoms/side effects and the support from the oncologist. This is a quantitative, descriptive cross-sectional study based on the database of the adverse drug reporting system and the questionnaire survey.   The side effects fatigue, pain and peripheral neuropathy were most frequently reported. The time consumption for reporting was considered short or very short and the majority thought that the questionnaire was fairly easy to very easy to use independent of computer habits. The oncologists where considered from a high extent to a very high extent being a support in handling the symptoms/side effects by two thirds of the respondents. Two fourths felt that the oncologists attended reported symptoms/side effects from a high extent to a very high extent. Because of a small sample and a relatively large drop-out no real conclusions can be drawn except the need for further development of the system.

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