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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.
421

The Synthesis and Evaluation of Functionalised Carbohydrates as Probes of Tumour Metastasis

Abu-Izneid, Tareq, n/a January 2005 (has links)
Sialyltransferases, CMP-sialic acid synthetases and CMP-sialic acid transport proteins play a crucial role in the construction of cell surface glycoconjugates. These proteins also have a pivotal role to play in a number of diseases, including cancer. The sialyltransferase enzymes are responsible for transfering sialic acids from the donor substrate (CMP-sialic acid) to growing cell surface glycoconjugate chains within the Golgi apparatus. The CMP-sialic acid synthetase enzymes are responsible for the synthesis of the CMP-sialic acid, the donor substrate of the sialyltransferases in the nucleus, while the CMP-sialic acid transport proteins are responsible for transporting CMP-sialic acid from the Cytosol to the Golgi apparatus. When these proteins function in an abnormal way, hypersialylation results, leading to an increased level of sialylation on the cell surface. This increased level of sialylation aids in the detachment of primary tumour cells due to an increase in the level of overall negative charge, causing repulsion between the cancer cells. Therefore, the sialyltransferase enzymes, CMP-sialic acid synthetases and CMP-sialic acid transport proteins are intimately involved in the metastatic cascade associated with cancer. Chapter 1 provides a general introduction of cancer metastasis, discussing the roles of three target proteins (CMP-sialic acid synthetases, CMP-sialic acid transport proteins and sialyltransferases), as well as discussing their substrate specificities, with an emphasis on their involvements in cancer metastasis. The Chapter concludes with an overview of the types of compounds intended to be utilised as probes or inhibitors of these proteins. Chapter 2 describes the general approach towards the synthesis of CMP-Neu5Ac mimetics with a sulfur linkage in the presence of a phosphate group in the general structure 38. The precursor phosphoramidite derivative 45 was prepared and isolated in a good yield using Py.TFA. Unfortunately, the target compound 38 could not be prepared. Chapter 3 describes an alternative strategy wherein S-linked sialylnucleoside mimetics, of the general structure 39, with a sulfur linkage, but no phosphate group, between the sialylmimetic and the ribose moiety in the base is targeted. A series of these S-linked sialylnucleoside mimetics were successfully prepared. Cytidine, uridine, adenosine and 5-fluorouridine nucleosides were used to create a library of different nucleosides and with structural variability also present in the sialylmimetic portion. This small 'library' of 15 compounds was designed to shed light on the interaction of these compounds with the binding sites of the sialyltranferase, CMP-sialic acid synthetase and/or CM-sialic acid transport protein. Approaches towards the synthesis of O-linked sialylnucleoside mimetics of the general structure 40 are described in Chapter 4. Several methodologies are reported, as well as protecting group manipulations, for successful preparation of these sialylnucleoside mimetics. Cytidine and uridine were employed as the nucleosides, thus allowing a direct comparison between the O- and S-linked sialylnucleoside mimetics in biological evaluation. It appears from these synthetic investigations that gaining access into the O-linked series is not as straightforward as for the S-linked series, with alternative protecting group strategies required for the different nucleosides. The biological evaluation of some of the compounds reported in Chapters 3 and 4 is detailed in Chapter 5. The sialylnucleoside mimetics were evaluated, by 1H NMR spectroscopy, for their ability to inhibit CMP-KDN synthetase. In addition, an initial 1H NMR spectroscopic-based assay was investigated for inhibition studies of α(2,6)sialyltranferase in the absence of potential inhibitors. The final chapter (Chapter 6) brings together full experimental details in support of the compounds described in the preceding Chapters.
422

Studies on Tumour Active Compounds with Multiple Metal Centres

Daghriri, Hassan January 2004 (has links)
Four tumour active trinuclear complexes: DH4Cl: [{trans-PtCl(NH3)2}2m-{trans-Pd( NH3)2(H2N(CH2)4NH2)2]Cl4, DH5Cl: [{trans-PtCl(NH3)2}2m-{trans-Pd( NH3)2(H2N(CH2)5NH2)2]Cl4, DH6Cl: [{trans-PtCl(NH3)2}2m-{trans-Pd( NH3)2(H2N(CH2)6NH2)2]Cl4, DH7Cl: [{trans-PtCl(NH3)2}2m-{trans-Pd(NH3)2-( H2N(CH2)7NH2)2]Cl4 and one dinuclear complex DHD: [{trans-PtCl(NH3)2}�-{ H2N(CH2)6NH2}{trans-PdCl(NH3)2]Cl(NO3), have been prepared and characterised based on elemental analyses, IR, Raman, mass and 1 H NMR spectral measurements. For the trinuclear complexes, the synthesis has been carried out using a step-up method branching out from the central palladium unit. A purity of about 95% has been obtained by repeated dissolution and precipitation. The activity against human cancer cell lines including ovary cell lines: A2780, A2780 cisR , A2780 ZD0473R , non small lung cell line: NCI-H640 and melanoma: Me-10538 have been determined based on MMT assay. Cell uptakes, DNA-binding have been determined for ovary cell lines: A2780, A2780 cisR . The nature of interaction with pBR322 plasmid DNA and ssDNA has been studied for trinuclear complexes DH4Cl, DH5Cl, DH6Cl and DH7Cl and the dinuclear complex DHD. Interaction of DH6Cl with adenine and guanine has also been studied by HPLC. The compounds are found to exhibit significant anticancer activity against cancer cell lines especially ovarian cancer cell lines: A2780, A2780 cisR and A2780 ZD0473R . DH6Cl in which the linking diamine has six carbon atoms is found to be the most active compound. As the number of carbon atoms in thelinking diamine is changed from the optimum value of six, the activity is found to decrease, illustrating the structure-activity relationship. The increase in uptake of the trinuclear complexes in A2780 cell line with the increase in size of the linking diamine coupled with the low molar conductivity values found for the solutions of the compounds suggest that the compounds would remain in solution as undissociated �molecules� and hence could cross the cell membrane by passive diffusion. Much lower resistance factors for the all the multinuclear compounds including DHD as applied to A2780 cisR cell line, as compared to that for cisplatin, suggest that the compounds are able to overcome multiple mechanisms of resistance operating in the cell line. All of the multinuclear complexes are expected to form long-range interstrand GG adducts with DNA, causing irreversible global changes in the DNA conformation but unlike cisplatin do not cause sufficient DNA bending to be recognized by HMG 1 protein. Increasing prevention of BamH1 digestion with the increase in concentration of the multinuclear compounds also provide support to the idea that the compounds because of the formation of a plethora of interstrand GG adducts are able to cause irreversible changes in DNA conformation. The results of the study show that indeed new trinuclear tumour active compounds can be found by replacing the central platinum unit in BBR3464 with other suitable metal units.
423

Exploring the experiences of people who have consented to tumour testing for a hereditary disposition to cancer

Opat, Annette January 2009 (has links)
Due to the costly and technically challenging nature of genetic testing, methods have been developed to target more specifically those who are at increased risk of carrying the Hereditary Non-Polyposis Colorectal Cancer (HNPCC) mutation. HNPCC is an inherited colorectal cancer syndrome. Testing of tumour material (which has previously been removed during surgery) for features of HNPCC has been found to be an effective and economic method of identifying those at higher risk of having a mutation. Only those at higher risk of having a mutation will undergo genetic testing. This practice of “tumour testing” has become widespread. / There is currently no clarity about requirements for consent prior to testing of stored tumour tissue. The person giving consent to tumour testing does not always have an appointment with a genetics service prior to giving consent. This can be contrasted to genetic testing on blood samples where laws and guidelines state that informed consent is required prior to genetic testing and that comprehensive genetic counselling and support should be provided as part of this process. Protocols for genetic testing have been developed as a result of extensive research around the impact and implications of genetic testing. / Consumer opinion and participation through research is an important aspect of health policy and guideline development. Accordingly the purpose of this study was to contribute to such development by gaining insight into the experiences, understandings, decision making processes and opinions of those who had given consent to have their own or their relatives tumour tested. Seventeen people who had given consent for tumour testing either for themselves, or on behalf of a deceased relative were recruited through a Familial Cancer Centre and in-depth interviews conducted. The interviews were transcribed and analysed using thematic analysis. / Some participants had no memory of consenting to tumour testing. Others remembered basic concepts. Negative implications of testing were unknown or viewed as unimportant. Participants did not understand the difference between tumour testing and germline testing. Despite lack of memory or understanding participants did not want additional or more detailed pre-test information although they did want more follow-up and support after receipt of results. The decision to consent to testing was made as soon as participants were informed of the availability of tumour testing - the major reason being to provide information for the family that would aid in cancer prevention. Participants were more concerned with accessibility to testing than pre test information and counselling. / Findings in this study indicated participants made decisions heuristically rather than systematically and this as well as participants’ opinions and other decision-making research has implications for the traditional view of informed consent around genetic related decisions. This in turn has implications for policy and guidelines in the area. Implications for current practise as a result of findings from this study include ensuring participants understand negative implications of testing and follow up and support of those with negative as well as positive results to tumour testing.
424

Gene polymorphisms influencing the cause and disease outcome of childhood central nervous system tumours

Ferguson, Anthea Elizabeth, Women's & Children's Health, Faculty of Medicine, UNSW January 2009 (has links)
Tumours of the central nervous system (CNS) are the second most common cancers diagnosed in children, yet the cause of this disease remains largely unknown. This thesis examines whether polymorphisms in folate-metabolising and glutathione S transferase (GST) genes influence the risk and disease outcome of childhood CNS tumours. 204 children aged ≤18 years diagnosed with a CNS tumour at the Sydney Children??s Hospital between 1989 and 2004 were included in the study. DNA samples were isolated from archival frozen and formalin-fixed paraffin-embedded tumour tissue. Polymorphisms in GST and folate pathway genes were examined using real-time PCR. Genotype distributions in children with CNS tumours were compared to those observed in a control panel of cord blood samples from 363 healthy newborns. Children carrying at least one variant allele for each of MTHFR 677 C>T, MTHFR 1298 A>C, MTR 2756 A>G, MTRR 66 A>G, and RFC 80 G>A were found to have a 2.8-fold greater risk of developing a CNS tumour than non-carriers (OR=2.80; 95%CI: 1.08-7.56, P=0.022), an association which was even more apparent in those children with an embryonal tumour (OR=4.54; 95%CI: 1.13-15.85, P=0.016). Results also showed that children with the GSTP1 105 Val/Val genotype were three times more likely to develop a CNS tumour of embryonal cell origin than children with the GSTP1 105 Ile/Ile or Ile/Val genotypes (OR=3.02; 95%CI: 1.34-6.46, P=0.005). No such association was observed for CNS tumours of glial cell origin. The GSTM1, GSTT1, and GSTP1 Ala114Val polymorphisms did not appear to be associated with the development of a childhood CNS tumour. In addition, children with the MTHFR 677 TT or RFC 80 AA genotypes were found to have a higher risk of death within 5 years of diagnosis compared to children with one or more MTHFR 677 C or RFC 80 G alleles, respectively (HR=5.52, 95%CI: 1.00-30.37, P=0.049 and HR=5.69, 95%CI: 1.38-23.51, P=0.016, respectively), after adjusting for other prognostic factors such as sex, age at diagnosis, period of diagnosis, and tumour grade. Conversely, children with the MTR 2756 AG or GG genotypes, or MTRR 66 AG or GG genotypes, were more likely to survive compared to those with the MTR 2756 AA or MTRR 66 AA genotypes, respectively (HR=0.21, 95%CI: 0.05-0.93, P=0.040 and HR=0.11, 95%CI: 0.02-0.53, P=0.006). Results presented in this thesis indicate that polymorphisms in folate-metabolising and GST genes may play a role in the aetiology and survival of childhood CNS tumours, and that this may vary depending on the histological sub-type of tumour.
425

Erythroid Kruppel-Like Factor and the Cell Cycle: A Role beyond Globin Gene Regulation

Michael Tallack Unknown Date (has links)
Erythropoiesis, the process of producing mature erythrocytes from the haematopoietic stem cells (HSCs) that reside in the bone marrow, is tightly regulated at both the cell and molecular level by a well defined set of extracellular cytokine signals and intracellular transcription factors. Diseases affecting erythropoiesis are among the most commonly inherited conditions and result from disturbances to the cellular and molecular events that normally regulate this process. Erythroid Kruppel-like factor (EKLF/KLF1) is a transcription factor that is essential for erythropoiesis. EKLF is the founding member of the Kruppel-like factor family of transcription factors that bind to GC rich CACC-Box elements within gene promoters and activate transcription. The β-like globin genes are critical targets of EKLF through its binding at sites within the proximal promoters and the upstream locus control region (LCR) enhancer. Mice lacking EKLF die prior to birth by E16 with a phenotype that closely resembles the human disease thalassaemia. Thalassaemia is due to mutations in the α or β-globin genes, leading to globin chain imbalance, red cell destruction and ineffective erythropoiesis. However, restoration of expression of γ-globin (a β-like gene) failed to prevent embryonic lethality in EKLF knockout mice and suggested that additional target genes were critical to erythropoiesis. This thesis describes investigation into the transcriptional network of EKLF and an in depth analysis of previously uncharacterised phenotypes present in the EKLF knockout mouse. I have identified a suite of target genes for EKLF that include critical components of the cells cycle. I have also tested the hypothesis that EKLF is able to function in vivo as a tumour suppressor gene. Additionally, I report a role for EKLF in the determination of cell fate within the haematopoietic system and describe the development of a new approach to globally understanding erythroid transcription factor function. A previously performed microarray transcriptional profiling study provided a set of potential target genes for EKLF. I have expanded on this study by identifying that the cell cycle genes p18INK4c, and E2f2 are direct transcriptional targets of EKLF, where binding of EKLF occurs at the promoter and a novel intronic enhancer region, respectively. I have also described a previously undiscovered cell cycle phenotype of aberrant entry into S-phase in EKLF -/- erythroid cells that is directly related to abrogated expression of E2f2. The Kruppel-like factor family of genes have been implicated as players in the tumour process. By constructing a model for the loss of EKLF within HSCs in vivo, I have tested whether EKLF is functional as a tumour suppressor. The loss of EKLF in vivo was found to be insufficient to generate erythroleukaemia, however did result in erythroid hyperplasia, extramedullary haematopoieis and a mild macrocytic anaemia. In addition to regulation of erythropoiesis, EKLF performs a critical role in the lineage choice for a megakaryocyte-erythroid progenitor (MEP) between the megakaryocytic and erythroid lineages. This thesis describes that in the absence of EKLF, MEPs fail to commit properly to either lineage and proceed along a promiscuous pathway sharing the hallmarks of both megakaryocytes and erythroid cells. A detailed molecular mechanism for this phenotype remains undetermined, but is likely to involve interactions with the megakaryocyte transcription factor Fli1 and other members of the Kruppel-like factor family, such as BKLF (KLF3). While the transcriptional mechanisms that drive erythropoiesis have been slowly discovered, the development of chromatin immunoprecipitation (ChIP) assays and next generation DNA sequencing technology has presented the potential to rapidly enhance the progression of these studies. In this thesis I describe the development of ChIP-seq using Applied Biosystems SOLiD technology, an approach to rapidly identify binding sites for erythroid transcription factors in an unbiased genome wide approach. The work described in this thesis has expanded the transcriptional network of EKLF to include critical components of the cell cycle and has suggested many additional target genes from ChIP-seq requiring validation. As one of the major transcription factor players during erythropoiesis, EKLF performs many critical functions that include the regulation of the cell cycle, lineage selection and erythroid development. I suggest that current and future studies of EKLF function will influence our understanding of erythropoiesis and refine our understanding of human conditions such as thalassaemia and erythroleukaemia.
426

Theoretical modelling of tumour oxygenation and influences on treatment outcome

Toma-Dasu, Iuliana January 2004 (has links)
<p>One of the main problems in curing cancer resides in the different microenvironment existing in tumours compared to the normal tissues. The mechanisms of failure are different for radiotherapy and chemotherapy, but they all relate to the poor blood supply known to exist in tumours. It is therefore very important to know the tumour microenvironmental conditions in order to devise techniques that will overcome the problems and will therefore improve the result of the treatment.</p><p>The aims of the thesis were the modelling of tumour oxygenation and the simulation of polarographic oxygen measurements in order to assess and possibly to improve the accuracy of the electrode in measuring tumour oxygenation. It also aimed to evaluate the implications of tumour microenvironment for the radiotherapy outcome.</p><p>The project used theoretical modelling as the main tool. The processes of oxygen diffusion and consumption were described mathematically for different conditions, the result being very accurate distributions of oxygen in tissues. A first simple model of tissue oxygenation was based on the oxygen diffusion around a single blood vessel. A more complex model built from the basic physical processes and measurable parameters allowed the simulation of realistical tissues with heterogeneous vasculature. This model also allowed the modelling of the two types of hypoxia known to appear in tumours and their influence on the tumour microenvironment. The computer simulation of tissues was also used for assessing the accuracy of the polarographic technique for measuring tumour oxygenation.</p><p>The results of this study have shown that it is possible to model theoretically the tissue oxygenation starting from the basic physical processes. The particular application of our theoretical simulation to the polarographic oxygen electrode has shown that this experimental method does not give the oxygen values in individual cells. Because the electrode measures the average oxygenation in a relatively large tissue volume, the resulting oxygen distributions are different from the real ones and the extreme high and low values are not detected. It has further been found that the polarographic electrode cannot make distinction between various types of hypoxia existing in tumours, the geometrical distribution of the hypoxic cells influencing mostly the accuracy of the measurement.</p><p>It was also shown that because of the averaging implied by the measurement process, electrode results should not be used directly to predict the response to radiation. Thus, the differences between the predictions in clinical tumour control obtained from the real or the measured oxygenations are of the order of tens of percents in absolute value. A method to improve the accuracy of the electrode, i.e. to improve the correlation between the results of the measurements and the actual tissue oxygenation, was proposed.</p><p>In conclusion, theoretical modelling has been shown to be a very powerful tool for predicting the outcome of radiotherapy and it has the advantage of describing the tumour oxygenation in the least invasive manner. Furthermore it allows the investigation of the invasiveness and the accuracy of various experimental methods.</p>
427

Tumour Targeting Using Radiolabelled EGF Conjugates : Preclinical Studies

Sundberg, Åsa Liljegren January 2004 (has links)
<p>Tumour targeted radiotherapy is an appealing approach for treatment of disseminated tumour cells. A targeting agent that specifically binds to a structure on tumour cells is then used to transport therapeutically relevant radionuclides. The epidermal growth factor receptor, EGFR, is overexpressed on tumour cells in several malignancies, e.g. highly malignant gliomas. In this thesis, three types of radiolabelled EGF-conjugates, aimed for targeting to EGFR-expressing tumour cells, were developed and studied: EGF-dextran labelled with <sup>125</sup>I, EGF labelled with <sup>211</sup>At, and two EGF-chelates, DTPA-EGF and Bz-DTPA-EGF, labelled with the radioactive metals <sup>111</sup>In and <sup>177</sup>Lu. </p><p>The targeting properties of radioiodinated EGF-dextran were first studied in cultured glioma cells. Radioiodine coupled to the dextran part of EGF-dextran was retained in cells appreciably longer than radioiodine coupled to EGF. This can give about 100 times increased radiation dose to tumour cells.</p><p>Targeting with <sup>211</sup>At-EGF was investigated in combination with the tyrosine kinase inhibitor gefitinib (Iressa™, ZD1839). The uptake of <sup>211</sup>At-EGF in EGFR-expressing tumour cells increased with increasing gefitinib concentrations. This was the case for both gefitinib-resistant and gefitinib-sensitive cell lines. The effect of the combined treatment on cell survival, however, differed between the cell lines in an unexpected way. In gefitinib resistant cells, combined treatment decreased cell survival approximately 3.5 times relative to <sup>211</sup>At-EGF treatment alone. In gefitinib sensitive cells, however, combined treatment increased the cell survival (i.e. a protective effect).</p><p>The EGF-chelates studied ([<sup>111</sup>In]DTPA-EGF, [<sup>111</sup>In]Bz-DTPA-EGF and [<sup>177</sup>Lu]Bz-DTPA-EGF) all bound specifically with high affinity (K<sub>d</sub>≈2 nM) to EGFR on cultured glioma cells. They were internalised after binding, and the cellular retention of radionuclides was high (60% remained after 45 h). A biodistribution study in mice showed that liver and kidneys accumulated a majority of the radioactivity. The EGF-chelates bound EGFR specifically also <i>in vivo</i>. A tumour-to-blood ratio of 25 was achieved in a preliminary study.</p>
428

Radioimmunotherapy in Experimental Head and Neck Squamous Cell Carcinoma : Tumour-targeting <i>in vitro</i> and <i>in vivo</i>

Cheng, Junping January 2005 (has links)
<p>Radioimmunotherapy (RIT) has been shown to be a practicable way to treat head and neck squamous cell carcinoma. A specific antibody recognizes the charasteristic structure of tumour cells when loaded with cytotoxic agents (toxins, drugs, radionuclides, etc). But RIT kills not only tumour cells with attached radionuclides but also adjacent tumour cells due to the “cross fire effect”. To be efficacious, RIT depends closely on suitable monoclonal antibody, on the properties of the chosen radionuclides, and on a suitable labelling method for attaching radionuclide to antibody. </p><p>In this study we initially used radionuclide-labelled cMAB U36, via linker DABI in order to improve the retention of radio-conjugates in the tumour cells. Improved retention is important because the longer the radionuclide remains in tumour cells, the more effective will the tumour cells be eradicated. In the investigation, both normal mice and HNSCC-bearing nude mice were used to compare our form of treatment against other radio-iodination methods. In the biodistribution study, normal mice showed that radioactive uptake in organs diminished with time, irrespectively of whether the conjugate was directly or indirectly labelled. But in thyroid, there was a tenfold greater accumulation of direct-labelled than of indirectly labelled conjugate.</p><p>In tumour-bearing nude mice, by contrast, the results showed promising uptake of radioactivity, but little uptake in direct-labelled conjugate in thyroid. Significant differences were observed on comparing tumour: organ ratios between 131I-cMAb U36 vs. 125I-DABI-cMAb U36.</p><p>In the present study, cMAb U36 labelled with 211Astatine was initially used to treat HNSCC in nude mice. The biodistribution of 211At-cMAb U36 did not reveal any significant difference between an antibody-blocked group and a non-blocked group. But it did highlight the characteristics of a successful targeting conjugate in HNSCC-bearing nude mice.</p><p>In the subcutaneous therapy experiment, most of the treated tumours (n=18) had disappeared by the 26th day, in both U36-blocked and non-blocked groups. Treatment in the intravenous therapy experiment had also proved effective. In the antibody non-blocked group, the smallest tumour volume was 25 mm3 (average 111 mm3) vis-á-vis 65 mm3 (average 145 mm3) in the blocked group. None of tumours grew again following treatment.</p>
429

Genetic Engineering of T Lymphocytes for Cancer Immunotherapy : Optimisation of Gene Transfer

Lindqvist, Camilla January 2006 (has links)
<p>T lymphocytes can be rendered specific against a wide range of antigens by the genetic transfer of a chimeric receptor, a fusion between the antigen-binding domain of an antibody and the signalling domain of a T cell receptor. The use of such chimeric T lymphocytes has shown promising results for cancer therapy. Previous experiments in our laboratory have shown low rates of gene transfer using retroviral vectors. In this study, investigations have been done to increase the number of genetically modified cells. Different enhancers such as PLL and polybrene have previously been used in combination with retroviral transduction. The optimal retroviral protocol in this study showed to be the use of retrovectors produced with twice the normal concentration of the plasmids encoding env and gag-pol rather than the use of the enhancers. A 6-day pre stimulation of T lymphocytes prior transduction together with a centrifugation step increased the rate of modified cells even further. Alternative approaches of gene transfer were also investigated, including plasmid transfection and adenoviral transduction. While transfection protocols yielded low numbers of modified cells, adenoviral vectors showed the highest rate of gene transfer.</p> / <p>Cancer är den sjukdom som idag, efter hjärt-kärl-sjukdomar, kräver flest dödsfall i i-länder. Som en alternativ behandlingsmetod mot cancer pågår just nu forskning om genetiskt förbättrade immunceller, s.k. chimära T lymfocyter, skulle kunna användas för att döda tumörceller. De chimära cellerna är utrustade med en konstgjord receptor som är en fusion av en antikropp och en signalkedja. Det gör att cellerna kan riktas mot ett brett urval av cancertyper. Att få cellerna att ta upp generna som behövs för den konstgjorda receptorn har visats sig vara problematiskt. Den här studien har därför som mål att förbättra cellernas förmåga att ta upp gener. För detta har vi använt oss av retrovirus- och adenovirus-system tillsammans med försök att få cellerna att spontant ta upp generna, sk. plasmid-transfektion. Studien har visat att de båda virussystemen ger högst antal modifierade celler. Olika substanser som tidigare har visat sig förhöja graden av gentillförsel har testats, men vår studie har visat att tillverkningen av virusvektorerna har större påverkan på resultaten än någon av de olika hjälpmedlen.</p>
430

Antibody-Based Radionuclide Targeting for Diagnostics and Therapy : Preclinical Studies on Head and Neck Cancer

Nestor, Marika January 2006 (has links)
<p>Antibody-based targeting techniques play an increasingly important role in cancer research. By targeting a structure that is abundant in tumour cells, but rare in healthy tissues, an antibody can mediate the delivery of radioactivity specifically to tumour cells in the body. This idea is particularly appealing for head and neck squamous cell carcinoma (HNSCC), as the advanced stages have a large fraction of spread disease that is difficult to treat with procedures available today. </p><p>In this thesis, we have investigated possible radioimmunotargeting structures for HNSCC, and found that CD44v6 is a suitable target for antibody-based radiotherapy and diagnostics in this patient group. We have identified radiohalogens as attractive nuclides for such use, and have investigated the possibility of radiohalogenating the anti CD44v6 chimeric monoclonal antibody (cMAb) U36. Several feasible labelling methods were identified, using both direct and indirect labelling. The cMAb U36 was then successfully labelled with <sup>211</sup>At and <sup>131</sup>I, and preclinically evaluated for therapeutic use. Results proved the astatinated conjugate to be most efficient in this context, demonstrating a specific and dose-dependent cytotoxicity. The cMAb U36 was then evaluated for diagnostic use in thyroid anaplastic carcinoma, using <sup>124</sup>I as the diagnostic nuclide. Results in tumour-bearing mice were promising, with all of the tumours identified in micro-PET studies.</p><p>These results demonstrate how antibody-based radionuclide targeting can provide more sensitive and specific methods for identifying and treating head and neck cancer, and hopefully help improve long-term survival rates for this patient group in the future.</p>

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