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Lee, Ann Siew Gek. "Chromosomal aberrations in breast cancer." Thesis, University of Oxford, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.276849.
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Koen, Liezl. "Chromosomal aberrations in the Xhosa schizophrenia population." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/1189.
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Thesis (PhD (Psychiatry))--Stellenbosch University, 2008.BACKGROUND: Schizophrenia is a heterogeneous illness resulting from complex gene-environment interplay. The majority of molecular genetic work done has involved Caucasian populations, with studies in these and Asian populations showing 2-32% of sufferers to have chromosomal aberrations. So far the discovery of a specific susceptibility mechanism or gene still eludes us, but the use of endophenotypes is advocated as a useful tool in this search. No cytogenetic studies of this nature have been reported in any African schizophrenia population. AIM: The aim of the study was to combine genotypic and phenotypic data, collected in a homogenous population in a structured manner, with the hope of characterising an endophenotype that could be used for more accurate identification of individuals with possible chromosomal abnormalities. METHODOLOGY: A structured clinical interview was conducted on 112 Xhosa schizophrenia patients. (Diagnostic Interview for Genetic Studies, including Schedules for the Assessment of Negative and Positive Symptoms.) Blood samples (karyotyping and/or FISH analysis) as well as urine samples (drug screening) were obtained and nine head and facial measurements were performed. Descriptive statistics were compiled with reference to demographic, clinical and morphological variables. Comparisons between mean differences for these variables were made.
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Veltman, Joris André. "Chromosomal aberrations during head and neck carcinogenesis." Maastricht : Maastricht : Universitaire Pers Maastricht ; University Library, Maastricht University [Host], 1999. http://arno.unimaas.nl/show.cgi?fid=6943.
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Nordgren, Ann. "Characterisation of chromosomal aberrations in childhood leukaemia /." Stockholm, 2001. http://diss.kib.ki.se/2001/91-628-4792-9/.
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Koen, Liezl. "Chromosomal aberrations in the Xhosa shizophrenia population /." Link to the online version, 2008. http://hdl.handle.net/10019/1697.
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Cuceu, Corina. "Telomere Dysfunction And Chromosomal Instability In Hodgkin Lymphoma." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS210/document.
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Le lymphome de Hodgkin est caractérisé, d’un point de vue histologique, par la présence de rares cellules tumorales nommées cellules de Reed et Sternberg, au sein d’un infiltrat cellulaire polymorphe, inflammatoire et réactionnel. Cette dernière résulte de la transformation tumorale de cellules lymphocytaires B qui acquièrent des propriétés d’échappement au système immun, de prolifération, de résistance à l’apoptose et une instabilité chromosomique. Néanmoins, la rareté des cellules tumorales, impliquant des problèmes techniques mais aussi de caractérisation des évènements primaires dans l’initiation de cette instabilité chromosomique, a été bien débattue dans la littérature. Mais les mécanismes impliqués dans l’instabilité chromosomique dans le lymphome de Hodgkin demeurent obscurs.La première partie de cette thèse a été consacrée à l’étude des mécanismes impliqués dans l’instabilité génomique du lymphome de Hodgkin via l’instabilité des microsatellites et l’instabilité chromosomique en utilisant 7 lignées de lymphome de Hodgkin. Nous avons montré pour la première fois l’implication des microsatellites dans l’instabilité génomique des lymphomes de Hodgkin (MSI-H (microsatellite instability-high) dans 3/7 lignées). De plus, nous avons montré que deux mécanismes favorisent l’émergence d’une instabilité chromosomique : le premier implique une instabilité télomérique qui est présente essentiellement dans les petites cellules tumorales induisant la formation des chromosomes dicentriques, des amplifications des gènes (Jak2 comme exemple) et des arrangements chromosomiques complexes. Le deuxième mécanisme est lié essentiellement à un défaut de réparation des cassures double-brin avec l’apparition des chromosomes dicentriques sporadiques et une fréquence importante des micronoyaux avec la formation des ponts anaphasiques.La deuxième partie de cette thèse a été consacrée à l’étude des mécanismes de maintenance des télomères dans les ganglions tumoraux du lymphome de Hodgkin (50 patients) comme dans les lignées tumorales. Nous avons montré qu’il existe une cohabitation entre les deux mécanismes importants de maintenance des télomères, l’activation de la télomérase d’une part et le mécanisme ALT (alternative lengthening of telomeres) d’autre part. Nous avons identifié la présence de petites cellules dans les ganglions hodgkiniens comme dans les lignées tumorales avec une forte activité de la télomérase par contre la cellule de Reed Sternberg est caractérisée par un profil ALT avec la présence des corps PML et une très faible activité de télomérase. La fréquence des cellules télomérase ou ALT varie d’un ganglion à un autre et d’une lignée à une autre. Un drastique raccourcissement télomérique a été observé dans les cellules exprimant la télomérase. Pour les cellules ALT, une grande hétérogénéité de la taille des télomères ainsi que la présence des chromosomes dicentriques sporadiques ont été détectées. Le suivi des patients à long terme pendant 10 ans, nous a permis d’établir une corrélation entre le profil ALT et la survenue de mortalités et de morbidités. De plus, l’étude de la radiosensibilité des lignées tumorales a montré que les lignées ALT sont plus résistantes que les lignées télomérases.La troisième partie de cette thèse a été consacrée à la validation de ces deux concepts d’instabilité chromosomique via l’instabilité télomérique et à celle des mécanismes de maintenance des télomères, en utilisant un modèle de lymphome de Hodgkin établi dans le laboratoire à partir de la lignée L428.Ces données auront une retombée clinique importante non seulement dans la compréhension et le traitement des lymphomes de Hodgkin mais aussi dans d’autres pathologies malignesThe study of Hodgkin lymphoma (HL), with its unique microenvironment and long clinical outcomes, has provided exceptional insights into several areas of tumour biology. Findings in HL have not only improved our understanding of human carcinogenesis, but have also pioneered its translation into the clinic.Tumoral cells in HL, called Hodgkin and reed Sternberg cells (HRS), are characterized by a highly altered genomic landscape with a wide spectrum of genomic alterations, including somatic mutations, copy number alterations, complex chromosomal rearrangements, and aneuploidy. Moreover, the scarcity of HRS cells and the resulting technical problems of their in situ characterization, the primary cytogenetic events and the clonality of these possible aberrations has been a matter of debate in the past. As a consequence, a few accepted and established HL cell lines are widely used in the majority of research projects conducted worldwide.In this thesis, first we have first investigated the possible mechanisms underlying genomic instability including microsatellite and chromosomal instability in HL cell lines. We provide the first evidence that the genomic instability observed in HL is related to microsatellite instability and chromosomal instability related to two major mechanisms: first, telomere fusion leading to dicentric chromosomes formation and breakage/fusion/bridge (B/F/B) cycles involving the repeated fusion and breakage of chromosomes following the loss of telomeres in small cells associated with the lower expression of TRF2, as well as an elevated copy number of the Jak2 gene and the presence of nucleoplasmic bridges containing telomere and centromere sequences. The second mechanism is related to defective DNA repair via non homologous end-joining (NHEJ) repair with the presence of nucleoplasmic bridges without telomere or centromere sequences, accompanied by the micronucleus without centromere sequences and a higher frequency of sporadic dicentric chromosomes.The second part of this thesis has focused on investigating telomere maintenance mechanisms (TMMs) not only in HL cell lines but also in lymph nodes of HL patients. A telomerase-independent mechanism for TMM in HL has been proposed in the absence of detectable telomerase activity (TA) in some cases. The major finding of this work has been the demonstration of the presence of both telomerase and ALT mechanism in lymph nodes of HL patients as well as in HL cell lines. We have identified a subset of tumors with some small cells expressing telomerase and Reed Sternberg cells containing ALT-associated PML bodies. A significant correlation was observed between telomere length and TMMs. Drastic telomere shortening was observed in cells with telomerase expression and elevated heterogeneity of telomere length was found in ALT profile cells. Interestingly, complex chromosomal rearrangements, included sporadic dicentric formation, were observed in ALT profile cell lines. Interestingly, the relationship between TMMs and all-cause mortality and morbidity during 10 years of follow-up of HL patients using cox proportion hazard models demonstrated a poor clinical outcome for HL patients exhibiting primarily ALT mechanisms. Similarly, higher radiation sensitivity was observed for cell lines with high telomerase activity compared to cell lines with the ALT profile
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Harvey, Alison Nichola. "The induction and production of chromosomal aberrations by restriction endonucleases." Thesis, Open University, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388300.
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El-Mehidi, N. S. "Bayesian network models of interdependent chromosomal aberrations in unstable cancer genomes." Thesis, University College London (University of London), 2009. http://discovery.ucl.ac.uk/17425/.
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Cancer results from the sequential accumulation of heterogeneous mutations and epigenetic changes, leading to “onco-selection” of cells with survival/growth advantages in specific microenvironments. Chemotherapy and radiotherapy act by damaging DNA; uncoupling DNA damage from cell death can cause treatment resistance. Deregulation of the DNA damage response (DDR) can result from aberrant expression of DDR-related genes, due to chromosomal aberrations. Solid tumours often have multiple, recurrent chromosomal aberrations, suggesting coordinated somatic evolution of cancer genomes via co-selection of interdependent chromosomal aberrations. This thesis investigates the hypothesis that “onco-selection” acts on unstable cancer genomes by selecting for multiple changes together. A comprehensive DDR signalling network was constructed. The cytogenetic location of its genes was analysed. The non-random genomic organisation of DDR genes partly coincided with regulation by shared transcription factors, notably oncogenic SNAIL. SNAIL expression was investigated in relation to hypoxia and apoptosis in xenografts of four human colorectal cancer cell lines. SW1222 and LS174T had weak and strong SNAIL expression, respectively, so could be used to investigate the role of SNAIL in treatment resistance through regulation of DDR genes. Bayesian Networks (BNs) were constructed to model probabilistic dependencies between the proposed co-selected, DDR-related chromosomal aberrations in breast, colorectal, lung, ovarian and prostate cancer. The significance of the models was assessed using newly-developed software. Breast cancer involved both co-selection of aberrations on different chromosomes and loss/gain of adjacent regions, whereas loss/gain of adjacent chromosomal regions predominated in the other cancers. A therapeutic combination of DDR targets (RELA, DVL1, E2Fs, CDC45L and MAP2K1/2) was proposed by mapping the predicted dependencies in the breast cancer BN model onto the DDR network, and analysing gene function and network topology. DDR network motif analysis further supported the importance of targeting RELA in combination therapies. This thesis provides insight into cancer resistance to DNA damaging therapies, and may help to predict new personalized combinations of targets to overcome treatment resistance.
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Southern, Shirley Anne. "Karyotypic analysis of cervical neoplasia : chromosomal aberrations and human papillomavirus infection." Thesis, University of Liverpool, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367063.
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Sjöling, Åsa. "Molecular genetic analysis of chromosomal aberrations in DMBA-induced rat fibrosarcomas /." Göteborg : Göteborg university, 2002. http://catalogue.bnf.fr/ark:/12148/cb39929313x.
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Woodfine, Kathryn Victoria. "Application of DNA micorarrays to assess DNA replication timing and chromosomal aberrations." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.615855.
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SOUZA, LEONARDO P. "Análise morfológica de imagens e classificação de aberrações cromossômicas por meio de lógica fuzzy." reponame:Repositório Institucional do IPEN, 2011. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10053.
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Dissertação (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Andersson, Robin. "Decoding the Structural Layer of Transcriptional Regulation : Computational Analyses of Chromatin and Chromosomal Aberrations." Doctoral thesis, Uppsala universitet, Centrum för bioinformatik, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-130999.
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Gene activity is regulated at two separate layers. Through structural and chemical properties of DNA – the primary layer of encoding – local signatures may enable, or disable, the binding of proteins or complexes of them with regulatory potential to the DNA. At a higher level – the structural layer of encoding – gene activity is regulated through the properties of higher order DNA structure, chromatin, and chromosome organization. Cells with abnormal chromosome compaction or organization, e.g. cancer cells, may thus have perturbed regulatory activities resulting in abnormal gene activity. Hence, there is a great need to decode the transcriptional regulation encoded in both layers to further our understanding of the factors that control activity and life of a cell and, ultimately, an organism. Modern genome-wide studies with those aims rely on data-intense experiments requiring sophisticated computational and statistical methods for data handling and analyses. This thesis describes recent advances of analyzing experimental data from quantitative biological studies to decipher the structural layer of encoding in human cells. Adopting an integrative approach when possible, combining multiple sources of data, allowed us to study the influences of chromatin (Papers I and II) and chromosomal aberrations (Paper IV) on transcription. Combining chromatin data with chromosomal aberration data allowed us to identify putative driver oncogenes and tumor-suppressor genes in cancer (Paper IV). Bayesian approaches enabling the incorporation of background information in the models and the adaptability of such models to data have been very useful. Their usages yielded accurate and narrow detection of chromosomal breakpoints in cancer (Papers III and IV) and reliable positioning of nucleosomes and their dynamics during transcriptional regulation at functionally relevant regulatory elements (Paper II). Using massively parallel sequencing data, we explored the chromatin landscapes of human cells (Papers I and II) and concluded that there is a preferential and evolutionary conserved positioning at internal exons nearly unaffected by the transcriptional level. We also observed a strong association between certain histone modifications and the inclusion or exclusion of an exon in the mature gene transcript, suggesting a functional role in splicing.
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Kameswara, Rao N. "Chromosomal aberrations and gene mutations induced in lettuce (Lactuca sativa L.) seeds during storage." Thesis, University of Reading, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373841.
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Finley, Jennifer C. "Telomere length and chromosomal instability in the neoplastic progression of Barrett's esophagus /." Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/6343.
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Peng, Yaojin. "Chromosomal aberrations, DNA damage, and gene mutations induced by seed ageing in barley (Hordeum vulgare)." Thesis, University of Reading, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336086.
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Ashton, Kevin John, and K. Ashton@griffith edu au. "Genetic Aberrations in Non-Melanoma Skin Cancer." Griffith University. School of Health Science, 2002. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20030818.122305.
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Genetic changes are hallmarks of cancer development involving the activation and/or inactivation of oncogenes and tumour suppressor genes, respectively. In non-melanoma skin cancer (NMSC) development, the initiation of genetic mutations results from exposure to solar ultraviolet radiation. Non-melanoma skin cancers are comprised of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Several related cutaneous lesions also exist, of which solar keratoses (SK) are widely accepted as a precursor dysplasia to SCC development. The study of recurrent genetic changes present within NMSC and SK should help reveal causative mutations in skin cancer development. Such analysis could also elucidate links in the genetic similarity of these dysplasia. The rapid screening of numerical changes in DNA sequence copy number throughout the entire genome has been made possible by the advent of comparative genomic hybridisation (CGH). This technique enables the identification of net gains and loss of genetic material within a tumour DNA sample. Chromosomal regions of recurrent gain or loss identify loci containing putative oncogenes and tumour suppressor genes, respectively with potential roles in NMSC tumourigenesis. Used in conjunction with tissue microdissection and universal degenerate PCR techniques this can enable the elucidation of aberrations in small histologically distinct regions of tumour. Such a technique can utilize archival material such as paraffin embedded tissue, which is the major source of neoplastic material available for cancer research. This study used the CGH technique to investigate aberrations in BCC, SCC and SK samples. The screening of copy number abnormalities (CNAs) in BCC revealed that although these tumours were close to diploid and generally genetically stable, they did contain several recurrent aberrations. The loss of genetic material at 9q was identified in a third of BCC tumours studied. This is characteristic of inactivation of the PTCH tumour suppressor gene, a known attribute in some sporadic BCC development. Validation of this loss was performed via loss of heterozygosity, demonstrating good concordance with the CGH data. In addition the over-representation of the 6p chromosome arm was revealed in 47% of biopsies. This novel CNA is also commonly observed in other cutaneous neoplasias, including Merkel cell carcinoma and malignant melanoma. This suggests a possible common mechanism in development and or promotion in these cutaneous dysplasias, the mechanisms of which have yet to be clearly defined. In contrast to BCC, numerical genetic aberrations in SCC and SK were much more frequent. Several regions of recurrent gain were commonly shared between both dysplasias including gain of 3q, 4p, 5p, 8q, 9q, 14q, 17p, 17q and 20q. Common chromosomal regions of loss included 3p, 8p, 9p, 11p, 13q and 17p. In addition loss of chromosome 18 was significantly observed in SCC in comparison to SK, a possible defining event in SK progression to SCC. The identification of shared genetic aberrations suggests a clonal and genetic relationship between the two lesions. This information further supports the notion for re-classification of SK to an SCC in situ or superficial SCC. Finally, the CNAs detected have been similarly observed in other squamous cell-derived tumours, for example cervical and head and neck SCC. This provides further evidence to common mechanisms involved in the initiation, development and progression of SCC neoplasia. This study has identified a number of recurrent chromosomal regions, some of which are novel in NMSC development. The further delineation of these loci should provide additional evidence of their significance and degree of involvement in NMSC tumourigenesis. The identification of the cancer-causing genes mapped to these loci will further demarcate the genetic mechanisms of BCC and SCC progression. An understanding of the events involved in skin cancer formation and progression should shed additional light on molecular targets for diagnostics, management and therapeutic treatment.
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Albanese, R. "The analysis of chemically induced chromosomal aberrations in the germ cells of male and female mammals." Thesis, Open University, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.374886.
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A number of methods are currently used for the detection of chemically-induced chromosome damage but all are subject to the criticisms that they are either time-consuming and labour intensive or require a large number of animals and can be insensitive. However, for human risk-assessment, conclusive evidence that compounds possess potential heritable hazards can still only come from mammalian germ cell studies. Thus, there is a need for less demanding germ cell tests that may be used to identify potential germ cell clastogens. One such system involves the use of one-cell mouse embryos. Although not as well validated as the currently available germ cell assays i.e. the dominant lethal test (DLT) and the heritable translocation test (HTT), it has the advantage that both structural and numerical chromosome aberrations can be directly analysed. The aim of this thesis was to i) fully validate the one-cell embryo test system (analysing both male and female germ cell effects) with a number of model clastogens and spindle poisons and ii) investigate the fate/survival of these chemically induced aberrant one-cell embryos through to the F1 generation. Sexually mature male or female mice were administered test compound* as a single ip dose and then mated at different stages of gametogenesis; for males the whole of the spermatogenic cycle was sampled; for females preantral as well as antral/Graafian follicle stages were sampled. The afternoon after mating, one-cell embryos were recovered from mated females, cultured overnight in a mitotic inhibitor and then prepared for chromosomal analysis. In embryos derived from matings involving dosed males, only damage induced in the spermatid and spermatozoa was transmitted to the F1 progeny. There was no significant damage from the spermatocyte or spermatogonial stages. In embryos derived from females dosed with chemical clastogens only damage induced in the preovulatory Graafian follicle stage was transmitted. The survival of these chromosomally aberrant embryos was investigated by analysing 3-day and post-implantation embryos as well as weaned F1 progeny. These studies show that chromosomally aberrant embryos are able to survive up to at least the early post-implantation stages. At implantation and post-implantation stages, when the embryonic genome is required for continued development, those embryos with gross chromosomal aberrations (as induced by MMS, CYC, MMC and VIN) die. However, if the induced damage does not involve deletions and/or duplications of DNA (e.g. balanced reciprocal translocations - as induced by EMS) the embryo inheriting such aberrations will survive to term. One chromosomally aberrant F1 offspring was detected in this system. Thus, the analysis of one-cell embryos is a sensitive and precise method for the detection of mutagenic potential in mammalian germ cells and has the advantage that both structural and numerical chromosome aberrations can be directly analysed. Furthermore, the studies have shown it to be less costly and more sensitive than either the DLT or HTT. However, the technically demanding methods involved in the preparation of one-cell embryos prevents their use for routine screening purposes. *The model compounds selected were methyl methane sulphonate (MMS), ethyl methane sulphonate (EMS), cyclophosphamide (CYC), trenimon (TRN), mitomycin C (MMC), busulphan (BSN), hexamethyl phosphoramide (HMPA), 5-fluorouracil (5FU), colcemid (COL), vinblastine sulphate (VBS) and diethyl stilboestrol (DES)
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Dennis, Thomas R. "The significance of chromosomal translocation breakpoints in adult solid tumors : a molecular cytogenetic study of chromosome 3 rearrangements in small cell carcinoma of the lung /." abstract and full text PDF (UNR users only), 1999. http://0-gateway.proquest.com.innopac.library.unr.edu/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:9961140.
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Morrison, Norma. "Molecular cytogenetics : its use in human gene mapping and the detection and definition of subtle chromosomal aberrations." Thesis, University of Glasgow, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.422483.
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Williams, Lisa. "Fluorescence in situ hybridisation (FISH) analysis of chromosomal aberrations in gastric tissue : the involvement of Helicobacter pylori." Thesis, Swansea University, 2004. https://cronfa.swan.ac.uk/Record/cronfa43067.
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Gastric cancer is a common cause of cancer death in the UK. It most often presents in patients when the disease is advanced, and hence treatment options are limited. As such, studies on the pre-malignant stages of gastric cancer, and interest in the mechanisms of the carcinogenic process (reactive oxygen species, ROS) and the agents that may drive the carcinogenic pathway {Helicobacter pylori infection), are important, with a view to improving disease outcome. This series of experiments has firstly shown, using CBMN assay +/- kinetochore staining and interphase FISH, that ROS causes aneuploidy of chromosomes 4, 8, 20 and 17(p53) in a human cell line. Secondly, gastric cells have been collected using endoscopic cytology brush techniques, and prepared, such that interphase FISH could be performed. Again, aneuploidy of chromosomes 4, 8, 20 and 17(p53) were detected in normal gastric mucosa, gastritis and intestinal metaplasia. The level of aneuploidy detected increased as disease severity increased. Amplification of chromosome 4, amplification of chromosome 20 and deletion of chromosome 17(p53) were the more significant findings. The degree of chromosomal abnormalities detected increased further, in a stepwise manner, when gastric dysplasia and gastric adenocarinoma cells were studied. Hence, a role for these abnormalities may exist in the initiation of, and the progression to, gastric cancer. The presence of H. pylori was also determined in the gastric tissue studied using histological analysis and PCR technology. Detection rates were comparable. The more virulent strain of H. pylori, Cag A, was found to be associated with increased disease pathology and chromosomal abnormalities, yet numbers were small. The amplification of chromosome 4 in gastric tissue was again highlighted in association with H pylori infection, hence it may reflect a role for chromosome 4 in the initiation of gastric cancer.
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Ortman, Agnes. "Increased knowledge and parents fertility decisions. The effect of the CUB-test on abortions." Thesis, Uppsala universitet, Nationalekonomiska institutionen, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-388813.
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New and more advanced prenatal tests have steadily been introduced in the Swedish maternity care system in the last 30 years. The combined test, CUB, was introduced step wise in Swedish maternal care from 2008 and onward. The CUB test detects children with chromosomal abnormalities prenatally and is offered at no charge for women in treated counties. This thesis investigate the reform using a difference-in-difference approach to determine the effect of the CUB test on the number of late abortions performed. My theoretical framework suggest that the introduction of CUB should increase the number of abortions of children with chromosomal aberrations. As supported by theory I find a positive effect of CUB on late abortions for my main group of interest, women 35-39 years old. These women were the ones most effected by CUB. The positive effect of 0.47 percentage units is statistically significant at the 10% level. It corresponds to a 3.6-7.1% decrease in the number of babies born with chromosomal aberrations.
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CAMPOS, ISIDA M. A. de. "Dosimetria biologica citogenetica em protecao radiologica .Analise de aberracoes cromossomicas radioinduzidas em linfocitos humanos." reponame:Repositório Institucional do IPEN, 1988. http://repositorio.ipen.br:8080/xmlui/handle/123456789/9913.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Henry, Marianne Patricia. "The genomic health of human pluripotent stem cells." Thesis, Brunel University, 2018. http://bura.brunel.ac.uk/handle/2438/17081.
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Human pluripotent stem cells are increasingly used for cell-based regenerative therapies worldwide, with the use of embryonic and induced pluripotent stem cells as potential treatments for a range of debilitating and chronic conditions. However, with the level of chromosomal aneuploidies the cells may generate in culture, their safety for therapeutic use could be in question. This study aimed to develop sensitive and high-throughput assays for the detection and quantification of human pluripotent stem cell aneuploidies, to assess any changes in their positioning in nuclei, as well as investigate the possible roles of lamins in the accumulation of aneuploidies. Using Droplet Digital PCR™, we optimised the detection of aneuploid cells in a predominantly diploid background. An assay was established for the sensitive detection of up to 1% of mosaicism and was used for the monitoring of low-level chromosome copy number changes across different cell lines, conditions and passages in the human pluripotent stem cells. In addition, fluorescence in-situ hybridisation was used to map genes ALB and AMELX on chromosomes 4 and X, respectively, in karyotype-stable chromosome X aneuploid lymphoblastoid cell lines. Our results demonstrated significant alternations in the gene loci positioning in the chromosome X aneuploid cell lines. Using the same established method, the positioning of ALB and AMELX was monitored, alongside the genomic instability with ddPCR™, in the different human pluripotent stem cell lines, conditions and passage. We demonstrated a highly plastic nuclear organisation in the pluripotent stem cells with many changes occurring within a single passage. Furthermore, these results were not exclusive to a single cell line or condition, regardless of the presence or absence of feeder cells and of passage number, and the flexibility of the chromatin organisation remained throughout the duration of the study. We demonstrated high levels of genomic instability with recurrent gains and losses in the AMELX copy number in the human embryonic stem cells during the course of our study, however no significant changes in their gene loci positioning from these abnormalities were observed. xvi | P a g e Additionally, we observed reduced levels of lamin B2 in the aneuploid lymphoblastoid cell lines and complete loss in some hPSC samples. Our results support recent findings that suggest a link between lamin B2 loss and the formation of chromosome aneuploidies in cell culture. In conclusion, our data demonstrates several key novel findings. Firstly, we have established a sensitive technique for the detection of up to 1% mosaicism, which to our knowledge is the most sensitive assay currently available. Secondly, we showed significant changes in the gene loci positioning between aneuploid and diploid cell lines. Thirdly, utilising our novel ddPCR™ assay, we demonstrated the karyotypical instability of hPCSs with consistent gains and/or loses of gene copy numbers in a short period of time in culture. When studying the effects of different growth conditions, we showed that the karyotypical instability was not exclusive to a single condition or a combination of conditions, and what is more, the karyotypical abnormalities detected were not observed to change the gene positioning of hPSCs significantly, with the genome organisation remaining plastic. Finally, our results support a potential association of lamin B2 loss and karyotypical instability. We conclude that more sensitive and robust techniques need to be readily used by clinicians for the screening of potential therapeutic hPSCs.
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De, la Seña Cesar A. "Evidence for genetic control of chromosomal aberrations, and C-band variants in the Japanese quail, Coturnix coturnix japonica /." The Ohio State University, 1990. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487676847115066.
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Darkhshan, Fatemeh. "Mapping of murine radiation-induced acute myeloid leukaemia susceptibility loci." Thesis, University of Reading, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367693.
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Paiva, Jean Carlos Gomes. "Biomonitoramento GenÃtico de Agricultores expostos a Pesticidas nos MunicÃpios de Tianguà e Ubajabra CearÃ." Universidade Federal do CearÃ, 2011. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=7093.
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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoNos Ãltimos anos, o uso de pesticidas na agricultura tem aumentado e associaÃÃes entre a exposiÃÃo a produtos quÃmicos agrÃcolas e danos ao DNA e cÃncer tem sido relatados. O Brasil à um dos lÃderes mundiais na utilizaÃÃo de pesticidas, no entanto, estudos que avaliem o impacto da exposiÃÃo ocupacional a pesticidas sobre a incidÃncia e mortalidade por cÃncer ainda sÃo escassos na populaÃÃo brasileira. O teste do cometa alcalino e a anÃlise de aberraÃÃes cromossÃmicas (AC) foram utilizados para avaliar danos primÃrios ao DNA em linfÃcitos do sangue perifÃrico de trabalhadores expostos a uma mistura complexa de pesticidas em duas pequenas comunidades rurais nos municÃpios de Tianguà e Ubajara, localizados no oeste do Estado do Cearà (Nordeste do Brasil). Estes MunicÃpios estÃo entre as maiores Ãreas agrÃcolas do Estado. O teste do cometa mostrou que o Ãndice e freqÃÃncia de danos observados nos grupos expostos foram significativamente maiores em relaÃÃo aos grupos controle (P <0,05). Por outro lado, nÃo foram detectadas diferenÃas significativas em relaÃÃo a AC estruturais e numÃricas nas comunidades avaliadas. AlÃm disso, os nÃveis observados de quebras da fita de DNA e freqÃÃncias de AC, estratificadas por tempo de exposiÃÃo, nÃo foram estatisticamente diferentes nos agricultores de ambas comunidades rurais. Os resultados sugerem que os danos causados por pesticidas na Ãrea de estudo nÃo foram significativos o suficiente para induzir mutaÃÃes permanentes ou interferir na formaÃÃo do aparelho mitÃtico. Danos mÃnimos causados pelos pesticidas podem ter sido submetidos a reparo celular, explicando a ausÃncia de AC estruturais e numÃricas. As anÃlises da Ãgua do reservatÃrio que serve de fonte para irrigaÃÃo das plantaÃÃes e abastece os municÃpios da regiÃo nÃo detectou contaminaÃÃo por resÃduos de pesticidas.
In recent years, the use of pesticides in agriculture has been steadily increasing, and associations between exposure to agricultural chemicals and DNA damage and cancer have been reported. Brazil is one of the world leaders in pesticide use; however, studies that evaluate the impact of pesticide exposure on cancer incidence and mortality are very scarce in the Brazilian population. The alkaline comet assay and the chromosome aberration (CA) test were used to evaluate primary DNA damage in the peripheral blood lymphocytes of workers exposed to a complex mixture of pesticides in two small rural communities in the municipalities of Tianguà and Ubajara, located in the western part of Cearà State (Northeast Brazil), which are among the largest agricultural areas of the state. The comet assay showed that the damage index and damage frequency observed in the exposed groups were significantly higher in relation to the controls (P < 0.05). On the other hand, no differences were detected regarding structural and numerical CAs in the communities evaluated. Additionally, the observed levels of DNA strand breaks and frequencies of CAs, stratified for exposure time, were not statistically different for individuals of either rural community. Our results suggest that the damages caused by pesticides in our study area were not great enough to induce permanent mutations or to interfere with mitotic apparatus formation; minimal pesticide damages could have undergone cellular repair, explaining the absence of structural and numerical CAs. Analyses of water from the reservoir that serves as a source for irrigation of crops and supplies the cities of the region did not detect contamination by pesticides.
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Alhourani, Eyad [Verfasser], Thomas [Gutachter] Liehr, Günter [Gutachter] Theißen, and Irmgard [Gutachter] Verdorfer. "Analysis and detection of cryptic chromosomal aberrations in chronic lymphocytic leukemia / Eyad Alhourani ; Gutachter: Thomas Liehr, Günter Theißen, Irmgard Verdorfer." Jena : Friedrich-Schiller-Universität Jena, 2017. http://d-nb.info/1177602059/34.
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Hartmann, Luise [Verfasser], and Karsten [Akademischer Betreuer] Spiekermann. "Deciphering the genetic heterogeneity in Acute Myeloid Leukemia : association of gene mutations with distinct chromosomal aberrations / Luise Hartmann ; Betreuer: Karsten Spiekermann." München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2017. http://d-nb.info/1132510929/34.
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Paiva, Jean Carlos Gomes. "Biomonitoramento Genético de Agricultores expostos a Pesticidas nos Municípios de Tianguá e Ubajabra Ceará." reponame:Repositório Institucional da UFC, 2011. http://www.repositorio.ufc.br/handle/riufc/16960.
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PAIVA, Jean Carlos Gomes. Biomonitoring genetic of farmers exposed to pesticides in the municipalities of Tiangua and Ubajara (Ceará, Brazil). 2011. 111 f. : Tese (doutorado) - Universidade Federal do Ceará, Programa de Pós-Graduação em Biotecnologia, Renorbio - Rede Nordeste de Biotecnologia. 2011.Submitted by demia Maia (demiamlm@gmail.com) on 2016-05-23T17:19:06Z No. of bitstreams: 1 2011_tese_jcgpaiva.pdf: 2591728 bytes, checksum: 4776344bdee5aac282c66c0a37608507 (MD5)
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Othman, Moneeb AK [Verfasser], Thomas [Gutachter] Liehr, Wim [Gutachter] Damen, and Irmgard [Gutachter] Verdorfer. "Analysis and detection of cryptic and complex chromosomal aberrations in acute leukemia / Moneeb AK Othman ; Gutachter: Thomas Liehr, Wim Damen, Irmgard Verdorfer." Jena : Friedrich-Schiller-Universität Jena, 2016. http://d-nb.info/1177613212/34.
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Wong, Chi-wai, and 黃志偉. "High resolution mapping of loss of heterozygosity and chromosomal aberrations using oligonucleotide single nucleotide polymorphismgenotyping arrays in colorectal adenoma to carcinoma progression." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2006. http://hub.hku.hk/bib/B3871923X.
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CUNHA, KELLY de P. "Aplicação de mapas auto-organizáveis na classificação de aberrações cromossômicas utilizando imagens de cromossomos humanos submetidos à radiação ionizante." reponame:Repositório Institucional do IPEN, 2015. http://repositorio.ipen.br:8080/xmlui/handle/123456789/23828.
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Dissertação (Mestrado em Tecnologia Nuclear)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Wong, Chi-wai. "High resolution mapping of loss of heterozygosity and chromosomal aberrations using oligonucleotide single nucleotide polymorphism genotyping arrays in colorectal adenoma to carcinoma progression." Click to view the E-thesis via HKUTO, 2006. http://sunzi.lib.hku.hk/hkuto/record/B3871923X.
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Grunwald, Monique. "Détection des anomalies chromosomiques par cytométrie en flux et localisation des points de translocation." Paris 6, 1986. http://www.theses.fr/1986PA066487.
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Goujon, Eric. "Etude de la toxicité de la sulcotrione et de ses produits de photodégradation." Thesis, Clermont-Ferrand 2, 2015. http://www.theses.fr/2015CLF22568/document.
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L’objectif de ce travail est l’étude de la plante face aux molécules issues de la phototransformation de la sulcotrione. La recherche d’anomalies a été menée sur des extrémités racinaires d’Allium cepa L. var. aggregatum par un dénombrement au microscope des anomalies chromosomiques causées par l’ajout des différents xénobiotiques. L’étude a été réalisée en deux temps. Tout d’abord l’impact génotoxique d’un mélange constitué de la sulcotrione et de ses photoproduits a été évalué. Puis les caractéristiques de chaque produit de dégradation ont été analysées indépendamment. Il s’est avéré que la sulcotrione et ses produits de transformation CMBA et XDD ont des caractéristiques de toxicité qui sont spécifiques de chacun d’entre eux, avec une toxicité plus importante pour XDD. Il a été observé que XDD peut s’hydrolyser. Les études sur les produits de seconde génération ont permis d’identifier HMBA qui présente de nombreuses similitudes avec l’acide salicylique et provoque notamment une croissance racinaire accrue chez les espèces monocotylédones testéesCytotoxicity and genotoxicity of non irradiated and irradiated sulcotrione were investigated in Allium cepa test. Then, the cytotoxic effects of 2-chloro-4-mesylbenzoic acid (CMBA) and xanthene-1,9-dione-3,4-dihydro-6-methylsulfonyl (XDD), the two main photoproducts of sulcotrione were investigated at different concentrations. We analyze plant response treated with sulcotrione phototransformation by-products. Chromosomal aberrations were observed in Allium cepa root meristems. First, we investigated the genotoxic impact of a sulcotrione mixture and its photoproducts. Then each by-product was independently tested. Sulcotrione CMBA and XDD have specific toxicity, and XDD has a greater toxicity. In our latest analysis we observed that XDD can be hydrolyzed. HMBA was identified as a salicylic acid derivative and can increase root growth in monocotyledonous species
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SILVA, MARCIA A. da. "Efeito citogenetico do sup(153) Sm-EDTMP em linfocitos perifericos de pacientes com cancer metastatico." reponame:Repositório Institucional do IPEN, 2001. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10924.
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Tese (Doutoramento)
IPEN/T
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Torres, Danila de Leone França e. Freitas. "Avaliação da toxicidade de efluente sanitário tratado e condicionado para aplicação na agricultura, utilizando Allium cepa, Daphnia similis e Vibrio fischeri, como organismos-teste." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/257984.
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Orientador: Alexandre Nunes PoneziDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo
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Resumo: O uso de efluente tratado na agricultura irrigada constitui uma alternativa adequada para a preservação de mananciais, além de ser uma importante fonte de nutrientes. No entanto, os riscos de toxicidade devem ser avaliados. Testes ecotoxicológicos apresentam-se como uma ferramenta apropriada, devido à sensibilidade dos organismos e sua ampla aceitação por órgãos governamentais e científicos. O objetivo do presente estudo foi avaliar a toxicidade aguda na fotobactéria marinha Vibrio fischeri e no microcrustáceo Daphnia similis (CE50) e do potencial citotóxico, genotóxico e mutagênico em Allium cepa (cebola) de um efluente sanitário tratado usado para irrigação. Os ensaios foram realizados no efluente bruto e nos tratados utilizados para irrigação: anaeróbio e pos-tratamento anaeróbio (nitrificado). Os resultados evidenciaram que o efluente bruto, apresentou uma maior variação dos valores de CE50 para ambos os organismos. O efluente anaeróbio apresentou um efeito tóxico agudo maior para V. fischeri que para D. similis. Já o nitrificado (pos-tratamento anaeróbio) apresentou uma toxicidade aguda menor para ambos os organismos testados. Na avaliação das aberrações cromossômicas em A. cepa, os efluentes tratados apresentaram uma redução do potencial citotóxico (p<0,05) em relação ao efluente bruto. Pode-se concluir que os testes escolhidos foram adequados para o monitoramento do efluente. Recomenda-se que o uso de efluente tratado na agricultura seja realizado de forma regrada, atentando para os padrões de Boas Práticas Agrícolas (GAP) e de toxicidade. Além disso, em escala real é necessário um estudo de monitoramento periódico que avalie impactos a longo prazo, incluindo testes de toxicidade crônica
Abstract: The use of the treated effluent in agriculture has proven to be an important alternative, since its preservation of water and its potential as source of nutrients, with low potential for negative impact on the environment. However, toxicity remains an important issue. Ecotoxicological tests are appropriate tools to evaluate the toxicity of effluents. The aim of this study was to evaluate acute toxicity on marine bacteria Vibrio fischeri, on micro crustacean Daphnia similis (EC50) and on Allium cepa (onion) (assessment of cytotoxic, mutagenic and genotoxic potencial) in treated sanitary effluent used for irrigation. We tested the raw effluent, and in its treatments, used for irrigation: anaerobic and anaerobic posttreatment (nitrified). Our results showed that the raw effluent had a greater variation of EC50 for both organisms, due to an intrinsic variability of its composition. The anaerobic effluent had a greater acute toxic effect on V. fischeri than for D. similis. Yet, the nitrified (anaerobic post-treatment stage) showed a lower toxicity for both tested organisms. We found a reduction in the citotoxical potential in A. cepa as compared to the raw efluente. We concluded that the tests chosen were adequate for monitoring the effluent since the organisms showed adequate sensitivity. It is therefore suggested that the use of treated wastewater in agriculture should be standardized, noting Good Agricultural Practices (GAP) and toxicity stardards. Furthermore for larger scale assumption it is necessary a periodic monitoring study to assess long term impacts, including chronic toxicity tests
Mestrado
Saneamento e Ambiente
Mestra em Engenharia Civil
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OLIVEIRA, ELAINE M. de. "Avaliacao do efeito biologico da radiacao beta do sup[90]Sr em celulas sanguineas humanas e elaboracao de curva dose resposta." reponame:Repositório Institucional do IPEN, 2000. http://repositorio.ipen.br:8080/xmlui/handle/123456789/10815.
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Dissertacao (Mestrado)
IPEN/D
Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP
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Carvalho, Antonio Alberto. "CARACTERIZAÇÃO DE PACIENTES COM INDICAÇÃO CLINÍCA PARA CARIÓTIPO EM UM HOSPITAL DE REABILITAÇÃO." Universidade Federal do Maranhão, 2006. http://tedebc.ufma.br:8080/jspui/handle/tede/1058.
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Previous issue date: 2006-06-16In this study the results of the evaluation cytogenetics of 694 patients with suspected of being carriers of chromosomal abnormality, seen in Sarah Network of Hospitals for Rehabilitation - San Luis Unit, in the period from December 1996 to January 2005.
Neste estudo são apresentados os resultados da avaliação citogenética de 694 pacientes, com suspeita de serem portadores de anomalia cromossômica, atendidos na Rede Sarah de Hospitais de Reabilitação - Unidade São Luís, no período de dezembro de 1996 a janeiro de 2005.
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Moretto, Johnny. "Etude moléculaire de mécanismes de résistance acquise aux dérivés du platine et évaluation pharmacologique de nouveaux dérivés du platine à activité antitumorale." Thesis, Dijon, 2011. http://www.theses.fr/2011DIJOS017.
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Les dérivés du platine (i.e. cisplatine et oxaliplatine) représentent une des classes pharmacologiques les plus utilisées en oncologie, notamment dans les cancers colorectaux. Cependant, leur efficacité est limitée par l’émergence de résistances acquises. Nous avons alors étudié in vitro dans différentes lignées cancéreuses coliques humaines (HCT116, LoVo, SW480, HT29) les conséquences à long terme des dérivés du platine lorsqu’ils sont utilisés dans des conditions tenant compte de la sensibilité cellulaire. Ils provoquent des cassures double-brin (objectivées par l’expression de -H2AX), dont le taux dépend du système p53/p21, du complexe MRN et du niveau de stabilité microsatellitaire. Ils induisent aux plus fortes concentrations ( IC50), une cytostase qui s’accompagne de la formation de cellules géantes macrocytaires et endopolyploïdes, dont certaines acquièrent un phénotype sénescent. Dans le même temps, l’activation des mécanismes de réparation des CDB varie en fonction du dérivé du Pt et de la lignée considérée. A plus long terme, des cellules « résistantes » se développent : elles ont une ploïdie normale, et se caractérisent par une plus grande résistance aux dérivés du platine et la présence de novo d’anomalies chromosomiques récurrentes leur conférant un avantage sélectif potentiel en terme de prolifération. Ces mécanismes pourraient contribuer à expliquer en clinique la survenue d’une résistance à une chimiothérapie pourtant initialement efficace. Parallèlement, nous avons évalué in vitro et in vivo de nouveaux complexes de platine obtenus par pharmacomodulation, et associant un noyau intercalant dérivé de la phénanthroline ou de l’acridine. Les résultats in vitro montrent globalement une amélioration significative de la cytotoxicité. Toutefois, un des composés les plus cytotoxiques in vitro, le [(5,6-diméthyl-1,10-phénanthroline) (S,S-diaminocyclohexane)platine(II)], n’exerce pas d’effet antitumoral dans un modèle syngénique de cancer colique chez le rat BD-IX, mais montre une néphrotoxicité marquée. Ces données soulignent l’insuffisance du criblage in vitro et la discordance in vitro/in vivoPlatinum compounds (i.e. cisplatin and oxaliplatin) represent a class of DNA-damaging agents widely used in clinic especially in the treatment of colorectal cancer. However, their effectiveness is restricted because of emergence of acquired resistance. Therefore, long-term effects of platinum compounds, used at conditions reflecting the in vitro cellular sensibility, were assessed in vitro in several human colon cancer cell lines (HCT116, LoVo, SW480, HT29). Their cytotoxicity is related to double-strand break formation (objectived by -H2AX expression), which depends on p53/p21 status, MRN complex and microsatellite stability of the cell line. Furthermore, at the highest concentrations ( IC50), cells stopped their proliferation and exhibited phenotypic alterations resulting from progressive polyploidy and/or senescence. In the same time, DNA repair systems are activated differently according to the platinum derivate and the cell line. At later stages, cells that are more resistant to platinum compounds than their parental counterpart emerged. They have recovered their basal level of ploidy and acquired de novo recurrent chromosomal aberrations. Such mechanisms could contribute to the recurrence of clinical malignancies, even after an effective initial response to chemotherapy. On the other hand, pharmacological evaluation of new platinum compounds with phenanthroline or acridine intercalating ligand was performed in vitro and in vivo. Globally, many compounds exhibited a higher cytotoxic effect than cisplatin or oxaliplatin in all cell lines studied. Unfortunately, in vivo investigations of one of the most cytotoxic compounds ([(5,6-dimethyl-1,10-phenanthroline) (S,S-diaminocyclohexane)platinum(II)]) did not exhibit antitumor effect in BD-IX rats bearing peritoneal carcinomatosis, whatever the route of administration used (systemic or local), but it displayed nephrotoxicity. These results query the in vitro/in vivo correlation and reconsider the place of the in vivo screening
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Cunha, Kelly de Paula. "Aplicação de mapas auto-organizáveis na classificação de aberrações cromossômicas utilizando imagens de cromossomos humanos submetidos à radiação ionizante." Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/85/85133/tde-05062015-140631/.
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O presente trabalho é resultado da colaboração de pesquisadores do Centro de Engenharia Nuclear (CEN) e de pesquisadores do Centro de Biotecnologia (CB), ambos pertencentes ao IPEN, para o desenvolvimento de uma metodologia que visa auxiliar os profissionais citogeneticistas fornecendo uma ferramenta que automatize parte da rotina necessária para a avaliação qualitativa e quantitativa de danos biológicos em termos de aberração cromossômica. A técnica citogenética, sobre a qual esta ferramenta é desenvolvida, é a técnica de aberrações cromossômicas. Nela, são realizadas preparações citológicas de linfócitos de sangue periférico para que metáfases sejam analisadas e fotografadas ao microscópio e, com base na morfologia dos cromossomos, anomalias sejam investigadas. Quando esta tarefa é realizada manualmente, os cromossomos são analisados visualmente um a um pelo profissional citogeneticista, logo, trata-se de um processo minucioso em virtude da variação geral na aparência do cromossomo, do seu tamanho pequeno e do grande número de cromossomos por célula. Para um diagnóstico confiável, é necessário que várias células sejam analisadas, tornando-se uma tarefa repetitiva e demorada. Neste contexto, foi proposto o uso dos mapas auto-organizáveis para o reconhecimento automático de padrões morfológicos referentes às imagens de cromossomos humanos. Para isso, foi desenvolvido um método de extração de características por meio do qual é possível classificar os cromossomos em: dicêntricos, anéis, acrocêntricos, submetacêntricos e metacêntricos, com acerto de 93,4 % em relação ao diagnóstico dado por um profissional citogeneticista.This work is a joint collaboration between Nuclear Energy Research Institute (IPEN), Nuclear Engineering Center and Biotechnology Center to develop a methodology aiming to assist cytogenetic professionals by providing a tool to automate part of the required routine to perform qualitative and quantitative evaluation of biological damage in terms of chromosomal aberration. The cytogenetic technique upon which this tool was developed, is the chromosome aberrations technique, in which cytological preparations of peripheral blood lymphocyte metaphases are performed to be analyzed and photographed under a microscope in order to investigating chromosomal aberration. Performed manually, the chromosomes are analyzed visually one by one by a cytogenetic professional, so it is a painstaking process due to the great deal of variation in the appearance of each chromosome, their small sizes and not to mention the high density of chromosomes per cell. In order to obtain a reliable diagnosis it is necessary that many cells be analyzed, which makes this a repetitive and time consuming process. In this context, the use of self-organizing maps for the automatic recognition of patterns relating to morphological pictures of human chromosomes has been proposed. For this, we developed a feature extraction method by which is possible to classify chromosomes in: dicentrics, ring-shaped, acrocentric, submetacentric and metacentric with 93.4% accuracy compared to diagnostic given by a professional cytogeneticist.
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Motta, Andreya Gonçalves Costa. "Avaliação Citogenética de Técnicos em Radiologia Expostos Ocupacionalmente à Radiação Ionizante." Pontifícia Universidade Católica de Goiás, 2018. http://tede2.pucgoias.edu.br:8080/handle/tede/3996.
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ANDREYA GONÇALVES COSTA MOTTA.pdf: 1269655 bytes, checksum: d3b8bb83fce2a80358844cba4c05d288 (MD5)Made available in DSpace on 2018-06-20T19:01:11Z (GMT). No. of bitstreams: 1 ANDREYA GONÇALVES COSTA MOTTA.pdf: 1269655 bytes, checksum: d3b8bb83fce2a80358844cba4c05d288 (MD5) Previous issue date: 2018-03-08
The understanding of the biological effects radioinducites in the organism can help the cytogenetic dosimetry in monitoring the health of professionals occupationally exposed to radiation, so radiology technicians must pay attention to all necessary and obligatory measures of protection because they are responsible for the procedures that refer to the diagnoses involving exposure to ionizing radiation. The objective of this research was to perform a cytogenetic analysis of 20 professional radiology technicians exposed occupationally to ionizing radiation through the collection of heparinized peripheral blood and culture of T lymphocytes to verify the frequencies of chromosomal aberrations and micronuclei. All subjects had to have more than 3 years of service time, regardless of age, sex, smoking habits or alcohol. The control group had the same age and sex as the exposed group. Micronucleus analysis occurred faster and more accurately than the analysis of chromosomal aberrations, suggesting that it is used as the first choice in radiological screening. Metaphase analysis and the cytokinesis blockade test allowed the quantification of a high frequency of unstable chromosomal aberrations and micronuclei in subjects with a workday from 6 hours to 12 hours daily. The results of the frequency of unstable chromosomal aberrations in the exposed group were 0.031 ± 0.030 and in the control group 0.002 ± 0.004. In the micronuclei frequencies of the exposed group the obtained result was 0.0035 ± 0.003 and in the control group 0,0004 ± 0.001 confirming the methodology of cytogenetic analysis as quality control in the biodosimetric investigation for the identification and prevention of possible genomic damages. Subsequent studies are needed to find out if factors such as smoking and alcoholism can influence changes in the health of these professionals.
A compreensão dos efeitos biológicos radioinduzidos no organismo pode auxiliar a dosimetria citogenética no monitoramento da saúde dos profissionais ocupacionalmente expostos a radiação, assim, os técnicos em radiologia devem se atentar a todas as medidas necessárias e obrigatórias de proteção por serem responsáveis pelos procedimentos que referentes aos diagnósticos clínicos que envolvam a exposição à radiação ionizante. O objetivo desta pesquisa foi realizar análise citogenética de 20 profissionais técnicos em radiologia expostos ocupacionalmente a radiação ionizante, através da coleta de sangue periférico heparinizado e cultura de linfócitos T para verificar as frequências de aberrações cromossômicas e de micronúcleos. Todos os indivíduos tinham que ter mais de 3 anos de tempo de serviço, independente da idade, sexo, hábitos tabagista ou etilista. O grupo controle teve a idade e sexo equiparados com o grupo exposto. A análise de micronúcleos ocorreu de forma mais rápida e precisa do que a análise de aberrações cromossômicas, sugerindo que ela seja utilizada como primeira escolha em triagem radiológica. A análise de metáfases e o teste de bloqueio de citocinese permitiu a quantificação de uma alta frequência de aberrações cromossômicas instáveis e de micronúcleos nos indivíduos com a jornada de trabalho entre 6 horas a 12 horas diárias. Os resultados encontrados da frequência de aberrações cromossômicas instáveis no grupo exposto foi 0,031±0,030 e no grupo controle 0,002±0,004. Nas frequências de micronúcleos do grupo exposto o resultado obtido foi 0,0035±0,003 e no grupo controle 0,0004±0,001 confirmando a metodologia de análise citogenética como controle de qualidade na investigação biodosimétrica para a identificação e prevenção de possíveis danos genômicos. Estudos subsequentes são necessários para averiguar se fatores como o fumo e o etilismo podem influenciar as alterações na saúde destes profissionais.
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Darai-Ramqvist, Eva. "Involvement of evolutionarily plastic regions in cancer associated CHR3 aberrations /." Stockholm, 2007. http://diss.kib.ki.se/2007/978-91-7357-192-0/.
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Anderson, Rhona M. "Complex chromosome aberrations induced by densely ionising radiation." Thesis, Brunel University, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.412322.
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Huang, H. E. "Chromosome aberrations targeting the NRG1 gene in cancer." Thesis, University of Cambridge, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.604700.
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Thirty-four breast and nine pancreatic cancer cell lines were surveyed for alterations of the NRG1 gene by fluorescence in situ hybridization (FISH). A recent chromosome translocation breakpoint that targets the NRG1 gene was found in five breast and two pancreatic lines. High-resolution mapping by two-colour FISH showed that the breakpoints were clustered in a 1.1 Mb interval within NRG1. RT-PCR showed an extensive complexity of NRG1 transcripts in the translocation-positive lines, suggesting that expression of the ligand is a consequence of these structural arrangements. This study was extended to primary tumour material to confirm the presence and prevalence of NRG1 translocation in uncultured cancer cells. I designed a FISH strategy (using a custom FISH probe-the Neuprobe), which was used in a high-throughput manner on archival paraffin embedded material in the form of tissue microarrays (TMAs).A survey of 339 primary breast carcinomas identified a disruption targeting NRG1 in approximately 6% of all cases examined. The common abnormality seen was a deletion in the 5’ end of the gene, often accompanied by amplification of the 3’ end. Genomic alteration of NRG1 was associated with ectopic expression of NRG1 α and β isoforms. Fine mapping confirmed that these breakpoints cluster within the same region seen in cell lines. These results were independently validated by array-based CGH, using a custom made array with overlapping BACS spanning 8p12. NRG1 translocation was associated with high-grade tumours, low HER2 expression, and high expression levels of FGFR1, TACC (both in close genomic proximity to NRG1). A further survey of 242 primary ovarian tumours identified the same abnormality in 10% of tumours.
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Crouch, Joelle H. "Chromosome aberrations in field strains of Blattella germanica." Thesis, Virginia Tech, 1993. http://hdl.handle.net/10919/42132.
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Maschio, Lucilene Regina. "Avaliação do potencial citotóxico, genotóxico e mutagênico das águas do Rio Preto na área de influência da região de São José do Rio Preto/SP. -." São José do Rio Preto : [s.n.], 2009. http://hdl.handle.net/11449/102733.
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Resumo: Devido às crescentes expansões demográficas e industriais observadas nas últimas décadas, o meio ambiente tem recebido uma carga significativamente crescente de efluentes domésticos, industriais e agrícolas, causando impactos severos nos ecossistemas e um potencial comprometimento à saúde humana. Dentre os efluentes domésticos, podemos citar uma gama de poluentes, tais como químicos de diversas categorias, além de contaminações por agentes biológicos diversos. Já os efluentes industriais contêm poluentes orgânicos e/ou inorgânicos, dependendo da atividade industrial. Baseando-se nestes dados, este trabalho teve como objetivo investigar, por meio de ensaios biológicos com dois organismos-teste, a possível presença de contaminantes com potencial citotóxico, genotóxico e mutagênico, que são despejados ao longo do rio Preto, inclusive na Represa Municipal de São José do Rio Preto. O material biológico utilizado neste estudo constituiu-se de sementes de Allium cepa (cebola) e peixes da espécie Oreochromis niloticus (Tilápia). Coletas de águas foram realizadas, sazonalmente, nos meses de agosto de 2006 e 2007 (estação seca) e março de 2007 e 2008 (estação chuvosa), em seis pontos distintos: Ponto 1 (P1), 8 km antes do represamento; Ponto 2 (P2), 1 km antes do represamento; Ponto 3 (P3), local de despejo do esgoto; Ponto 4 (P4), margem oposta do despejo do esgoto; Ponto 5 (P5), saída do represamento; Ponto 6 (P6), 1 km após o represamento. Análises químicas foram realizadas para todas as coletas realizadas. Para a realização do estudo, 100 sementes de Allium cepa foram submetidas à germinação, em placa de Petri, em amostras de águas coletadas nos seis diferentes pontos do rio Preto, em água ultra pura (controle negativo) e em uma substância reconhecidamente aneugênica (Trifluralina - controle positivo), sempre à temperatura ambiente... (Resumo completo, clicar acesso eletrônico abaixo)Abstract: Due to increasing population and industrial expansion observed in recent decades, the environment has received a significant increased burden of domestic industrial and agricultural sewerage, which can cause severe impacts on ecosystems, and a potential damage to human health as well. A wide range of harmful pollutants can be found in domestic effluent, such as chemicals from various categories, in addition to contamination by various biological agents. On the other hand, industrial effluents contain organic and / or inorganic pollutants, depending on industrial activity. Based on these data, this study aimed to investigate, by means of biological tests with two test-organism, the possible presence of contaminants with cytotoxic, genotoxic and mutagenic potential, which are dumped along the Preto river, an important river that flows in the region of Sao Jose do Rio Preto/SP. The biological material used in this study consisted of seeds of Allium cepa (onion) and one specie of fish (Tilapia: Oreochromis niloticus). Water samples were taken seasonally in August 2006 and 2007 (dry season) and March 2007, and 2008 (rainy season), in six distinct sites: Site 1 (S1), 8 km before the damming, Site 2 (S2), 1 km before the damming, Site 3 (S3), place of sewerage discharge; Site 4 (S4), opposite margin of sewage discharge, Site 5 (S5), end of the damming; Site 6 (S6) 1 km after damming. Chemical analyses were performed for all collected samples. For the study, 100 seeds of A. cepa were submitted to germination in Petri dishes with samples water from six different sites of the Preto river, Ultra pure water (negative control), and with an aneugenic substance (Trifluralin - positive control). For most of collection points and periods studied, root meristems cells of A. cepa, exposed to water samples collected along the Preto river, showed no significant differences... (Complete abstract click electronic access below)
Orientador: Maria Aparecida Marin-Morales
Coorientador: Maria Tecília Vilela de Azeredo-Oliveira
Banca: Regina Teresa Rosim Monteiro
Banca: Carmem Silvia Fontanetti Christofoletti
Banca: Eduardo Alves de Almeida
Banca: Mary Massumi Itoyama
Doutor
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AUFFRET, PASCALE. "Malformations et tube neural et aberrations chromosomiques." Rennes 1, 1993. http://www.theses.fr/1993REN1M078.
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Bhatt, Samarth. "Segregation analysis of paracentric inversions in human sperm." Montpellier 1, 2008. http://www.theses.fr/2008MON1T002.
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Les inversions paracentriques sont des anomalies chromosomiques généralement considérées comme inoffensives. Toutefois, des cas de porteurs de chromosomes remaniés issus d'inversions paracentriques ont été rapportés, soulignant la nécessité d'étudier le comportement méiotique de ces anomalies. Seules quelques études ont été pratiquées, utilisant la technique de fécondation croisée Homme-Hamster, le typage génétique des spermatozoïdes (sperm typing) ou l'hybridation in situ fluorescente (FISH) par marquages centromériques ou télomériques. Afin d'améliorer l'efficacité de l'étude méiotique des inversions paracentriques, nous avons développé l'utilisation des sondes BAC qui permettent une localisation chromosomique précise des points de cassures chromosomiques et l'identification de tous les produits méiotiques des inversions dans le sperme humain. Les points de cassures et la ségrégation méiotique de 3 inversions paracentriques, inv(5)(q13. 2q33. 1), inv(9)(q21. 2q34. 13) et inv(14)(q23. 2q32. 13), ont ainsi été déterminés. Les taux de recombinants observés dans ces 3 inversions varient de 3,72% à12,55%. Cette localisation des points de cassures et l'analyse des séquences d'ADN adjacentes sont essentielles pour mettre en évidence la formation de boucles d'inversion, pour déterminer le risque de recombinaison à terme, ainsi que pour étudier les mécanismes méiotiques de formation des recombinaisons. Ainsi, la présence de régions d'ADN riches en recombinaisons et en duplications inter-chromosomiques a été mise en évidence, en complément de la formation de recombinants chromosomiques. Par ailleurs, une nouvelle technique de FISH multi-couleurs 3D (3D MCB FISH) a été adaptée aux spermatozoïdes humains pour l'analyse in situ des ségrégations. Cette approche permet de visualiser in situ les inversions paracentriques et d'estimer la fréquence de tous les types de recombinants issus de boucles d'inversion, de recombinaisons U-loop ou de processus de cassure/fusion des chromatides-soeurs.