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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.
1

Défis des banques centrales des pays émergents : les implications de la libéralisation financière sur la politique monétaire et la régulation du système bancaire / Challenges to central banking from financial liberalization in developing countries : implications for monetary and banking policymaking

Sosa Navarro, Ramiro 08 December 2008 (has links)
Cette thèse est consacrée à l'étude des conséquences de la libéralisation des marchés financiers sur la politique monétaire et la régulation du système bancaire dans les pays émergents. La première partie présente des estimations des taux de recouvrement et des probabilités de non payement des titres du gouvernement argentin. Par la suite, cette étude présente un modèle macroéconomique qui permet d'analyser les limites et conséquences potentielles de la politique monétaire dans un contexte caractérisé par le risque de défaut de l'état. Ceci est une approche qui semble négligée par la littérature. La deuxième partie résume la littérature concernant la relation entre la présence des banques étrangères et la stabilité macroéconomique. Ensuite, l'impact des banques étrangères sur le niveau et la volatilité du crédit réel est estimé dans un panel des pays d'Amérique Latine pour la période 1995:1-2001:4. Ceci est le primer travail qui applique des techniques ARCH pour l'analyse de ce sujet. / This thesis is focused on the implications of financial liberalization in monetary and banking policymaking. The first half of the work simultaneously estimates recovery values and probabilities of default implicit on market prices of the Argentine sovereign bonds. It conducts an empirical research contributing with evidence to the existing limited literature. It also presents a macroeconomic model that allows the analysis of limits and potential consequences of monetary policy in an environment characterized by sovereign default risk. An approach almost disregarded by literature. The second half surveys the literature that relates foreign bank presence with macroeconomic stability and estimates the impact of foreign bank presence on both the level and the volatility of real credit in a panel of eight Latin American countries over the period 1995:1 -2001:4. This is the first time that ARCH techniques are used to analyse this topic.
2

Alterações genômicas em tumores de glândulas salivares

Coelho, Miriam Marangon [UNESP] 09 December 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:26:02Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-12-09Bitstream added on 2014-06-13T18:29:20Z : No. of bitstreams: 1 coelho_mm_me_botib.pdf: 1279286 bytes, checksum: c9db6d651dfd0584937d8d5948869e47 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Os tumores de glândulas salivares (TGS) são lesões raras que apresentam heterogeneidade morfológica e sobreposição histológica entre os vários subtipos de tumores. Neste estudo foi utilizada a técnica de hibridação genômica comparativa de alta resolução (HR-CGH) em 64 amostras de TGS, incluindo: 27 adenomas pleomórficos (AP); 11 tumores de Warthin (TW); seis carcinomas ex-adenomas pleomórficos (CXAP); seis carcinomas adenóides císticos (CAC); quatro carcinomas mucoepidermóides (CME); três carcinomas ductais salivares (CDS); três adenocarcinomas (ACAR); dois oncocitomas (ON) e dois carcinomas epiteliaismioepiteliais (CEM). Destas, 47 amostras eram provenientes de tecidos fixados em formalina e em blocos de parafina (FFEP) e 17 de tecidos a fresco. Após a microdissecção, o DNA genômico foi amplificado e marcado por técnica baseada na PCR (SCOMP) e por nick translation, respectivamente. Os cromossomos foram cariotipados usando a imagem DAPI invertido e a intensidade do sinal de hibridação foi determinada ao longo de cada cromossomo. Uma biblioteca com amostras de DNA normais foi construída para selecionar os limites superiores e inferiores para perdas e ganhos cromossômicos. Em todos os casos, as perdas genômicas foram observadas mais freqüentemente do que os ganhos. Na análise comparativa das regiões mínimas comuns detectadas pela HR-CGH envolvendo todos os tipos tumorais, foram observadas alterações genômicas comuns aos diversos tipos, como também exclusivas para os diferentes tipos histológicos. As regiões genômicas consistentemente alteradas nos dois subgrupos tumorais com maior número amostral (adenomas pleomórficos e tumores de Warthin) foram investigadas em bancos de dados para a seleção de genes candidatos que pudessem estar relacionados com a etiologia destes tumores. Os genes NEDD9 (6p24-p25), PPARG (3p25) e c-MYC (8q24.21) foram... / Salivary gland tumors (SGT) are uncommon lesions showing morphologic heterogeneity and histologic overlap among various tumoral subtypes. In the present study, high resolutioncomparative genomic hybridization (HR-CGH) method was performed in 64 SGT samples, including 27 pleomorphic adenomas (PA), 11 Warthin’s tumors (WT), six carcinoma ex pleomorphic adenoma (CXPA), six cystic adenocarcinomas (CAC), four mucoepidermoid carcinomas (MEC), three salivary ductal carcinomas (SDC), three adenocarcinomas (ACAR), two oncocitomas (ON), and two epithelium-myoepithelium carcinomas (EMC). Among these samples, 47 were formalin-fixed and paraffin embedded tissues and 17 were fresh tissues. After laser capture microdissection (LCM), the DNA samples were amplified and labeled by PCR-based methods (SCOMP) and nick translation reaction, respectively. Chromosomes were karyotyped based on their inverted DAPI image and the relative hybridization signal intensity was determined along each chromosome. A library with differentially labeled normal samples was built to select the superior and inferior limits for chromosomal gains and losses. Genomic losses were more frequently observed than gains. The comparison among all tumor samples showed common chromosomal imbalances and also exclusive genomic alterations related to the different histological tumor types. Non-random genomic regions involved in pleomorphic adenomas and Warthin´s tumors were investigated in databases in order to select candidate genes that could be related to the etiology of these tumors. The NEDD9 (6p24-p25), PPARG (3p25) and c-MYC (8q24.21) genes were selected and the gene transcript levels were evaluated by quantitative real time PCR (qRT-PCR) in PA samples. In accordance to the HR-CGH results, it was observed high transcript levels of NEDD9 in 17 out of 37 PA; low levels of PPARG was detected in 11 out of 36 samples; and high levels... (Complete abstract click electronic access below)
3

Alterações genômicas em tumores de glândulas salivares /

Coelho, Miriam Marangon. January 2009 (has links)
Orientador: Silvia Regina Rogatto / Banca: Edigard Graner / Banca: Claudia Aparecida Rainho / Resumo: Os tumores de glândulas salivares (TGS) são lesões raras que apresentam heterogeneidade morfológica e sobreposição histológica entre os vários subtipos de tumores. Neste estudo foi utilizada a técnica de hibridação genômica comparativa de alta resolução (HR-CGH) em 64 amostras de TGS, incluindo: 27 adenomas pleomórficos (AP); 11 tumores de Warthin (TW); seis carcinomas ex-adenomas pleomórficos (CXAP); seis carcinomas adenóides císticos (CAC); quatro carcinomas mucoepidermóides (CME); três carcinomas ductais salivares (CDS); três adenocarcinomas (ACAR); dois oncocitomas (ON) e dois carcinomas epiteliaismioepiteliais (CEM). Destas, 47 amostras eram provenientes de tecidos fixados em formalina e em blocos de parafina (FFEP) e 17 de tecidos a fresco. Após a microdissecção, o DNA genômico foi amplificado e marcado por técnica baseada na PCR (SCOMP) e por nick translation, respectivamente. Os cromossomos foram cariotipados usando a imagem DAPI invertido e a intensidade do sinal de hibridação foi determinada ao longo de cada cromossomo. Uma biblioteca com amostras de DNA normais foi construída para selecionar os limites superiores e inferiores para perdas e ganhos cromossômicos. Em todos os casos, as perdas genômicas foram observadas mais freqüentemente do que os ganhos. Na análise comparativa das regiões mínimas comuns detectadas pela HR-CGH envolvendo todos os tipos tumorais, foram observadas alterações genômicas comuns aos diversos tipos, como também exclusivas para os diferentes tipos histológicos. As regiões genômicas consistentemente alteradas nos dois subgrupos tumorais com maior número amostral (adenomas pleomórficos e tumores de Warthin) foram investigadas em bancos de dados para a seleção de genes candidatos que pudessem estar relacionados com a etiologia destes tumores. Os genes NEDD9 (6p24-p25), PPARG (3p25) e c-MYC (8q24.21) foram... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Salivary gland tumors (SGT) are uncommon lesions showing morphologic heterogeneity and histologic overlap among various tumoral subtypes. In the present study, high resolutioncomparative genomic hybridization (HR-CGH) method was performed in 64 SGT samples, including 27 pleomorphic adenomas (PA), 11 Warthin's tumors (WT), six carcinoma ex pleomorphic adenoma (CXPA), six cystic adenocarcinomas (CAC), four mucoepidermoid carcinomas (MEC), three salivary ductal carcinomas (SDC), three adenocarcinomas (ACAR), two oncocitomas (ON), and two epithelium-myoepithelium carcinomas (EMC). Among these samples, 47 were formalin-fixed and paraffin embedded tissues and 17 were fresh tissues. After laser capture microdissection (LCM), the DNA samples were amplified and labeled by PCR-based methods (SCOMP) and nick translation reaction, respectively. Chromosomes were karyotyped based on their inverted DAPI image and the relative hybridization signal intensity was determined along each chromosome. A library with differentially labeled normal samples was built to select the superior and inferior limits for chromosomal gains and losses. Genomic losses were more frequently observed than gains. The comparison among all tumor samples showed common chromosomal imbalances and also exclusive genomic alterations related to the different histological tumor types. Non-random genomic regions involved in pleomorphic adenomas and Warthin's tumors were investigated in databases in order to select candidate genes that could be related to the etiology of these tumors. The NEDD9 (6p24-p25), PPARG (3p25) and c-MYC (8q24.21) genes were selected and the gene transcript levels were evaluated by quantitative real time PCR (qRT-PCR) in PA samples. In accordance to the HR-CGH results, it was observed high transcript levels of NEDD9 in 17 out of 37 PA; low levels of PPARG was detected in 11 out of 36 samples; and high levels... (Complete abstract click electronic access below) / Mestre
4

Improvement of Automotive Article Placement and Workload Distribution in Warehousing

Berggren, Erik January 2016 (has links)
Purpose – The purpose is to: Improve the efficiency of warehouses operations as well as reduce its workload imbalances by altering the warehouse layout and work zones at a storage area. This was done by answering the following research questions: What is the current state of the sites efficiency and workload imbalances? How can the warehouse layout be designed to increase the efficiency? How can warehouse work zones be altered to reduce workload imbalances? Method – The purpose was achieved through a case study at a vehicle manufacturing facility. By studying established methods of efficiency, layout designs and workload imbalances, ways of improving the operations was discovered. The effects of these methods were then tested through the case.   Findings –There are two categories improving efficiency, namely increasing output or decreasing input. The study also provides examples of ways to do both, and verifies them at the case company. The focus of both methods is a decrease in travel distance which proved to be a reliable way of increasing efficiency. Workload imbalances can be decreased by sharing workload between the resources. The case shows the result of two different resources with unequal workload and discusses the trade-off between efficiency and workload equality. Implications – The practical implications of the study is guidelines for how efficiency can be increased and how workload imbalances can be decreased. The academic implications are verifications of the used theories. Limitations – This study focuses on a restricted part of the storage process, namely traveling. There are more processes which could be included to further benefit the overall efficiency, these have however been excluded to limit the scope. The study also uses a heuristic approach based on prior research which means that the optimal solution might still be unknown. Keywords – Efficiency, workload imbalances, storage management, family grouping
5

The implementation of the affirmative action policy in the South African Military Health Service (SAMHS) 1995 - 2000

Motumi, N E 28 August 2007 (has links)
It is both a Constitutional imperative and the South African government's policy that the historical imbalances of the past be redressed. As a result thereof, the SANDF as a state entity is expected to comply with these stipulations. The objectives of this study are therefore to examine the nature of the policy of affirmative action in the SAMHS, and the nature of the problems experienced with regards to the implementation of this policy within this organisation during the period 1995 - 2000. On examining the nature of affirmative action policy in the SAMHS, it becomes obvious that this organisation did not have blacks as commissioned officers prior 1994. The number of black officers currently found within the SAMHS appears to have resulted from the integration process. Further analysis reveals that the SAMHS did not utilise the opportunity provided by the Defence Review in 1998 to become representative. Strategic positions were therefore still held by former white SADF members during the period under review. The sunset clause which was accepted during the political negotiations (1990 - 1994) seems to have contributed to the non implementation of this policy because the old guards' positions were secured during the first five years of the new democratic dispensation. / Dissertation (M (Political Policy Studies))--University of Pretoria, 2007. / Political Sciences / M (Political Policy Studies) / unrestricted
6

Essays in international economics and macroeconomics

Barattieri, Alessandro January 2011 (has links)
Thesis advisor: Fabio Ghironi / Thesis advisor: Susanto Basu / The present dissertation is composed by three essays. The first essay is titled ``Comparative Advantage, Service Trade, and Global Imbalances''. The large current account deficit of the U.S. is the result of a large deficit in the goods balance and a modest surplus in the service balance. The opposite is true for Japan, Germany and China. Moreover, I document the emergence from the mid-nineties of a strong negative relation between specialization in export of services and current account balances in a large sample of OECD and developing countries. Starting from these new stylized facts, I propose in this essay a ``service hypothesis'' for global imbalances, a new explanation based on the interplay between the U.S. comparative advantage in services and the asymmetric trade liberalization process in goods trade versus service trade that took place in the last 15 years. I use a structural gravity model to quantify the extent of this asymmetry. I show that a simple two-period model can rationalize the emergence of current account deficits in the presence of such asymmetric liberalization. The key inter-temporal mechanism is the asymmetric timing of trade policies, which affects savings decisions. Finally, I explore the quantitative relevance of this explanation for global imbalances. A multi-period version of the model, fed with the asymmetric trade liberalization path found in the data, generates a current account deficit of about 1% of GDP (roughly 20% of what was observed in the U.S. in 2006). The policy implications of the analysis proposed could be relevant for the evolution of the WTO DOHA Development Round. A major focus on services, in fact, could help expanding the ``policy space'' faced by the negotiators, possibly increasing the likelihood of a successful conclusion of the round. Moreover, this paper inform also the recent debate about the need of a revaluation of the yuan. Allowing the U.S. to increase its exports of services (not necessarily to China) might help alleviating global imbalances even without movements in the exchange rates. The second essay is titled ``Estimating Trade and Investment Flows: Partners and Volumes''. I present empirical evidence from a large sample of countries for the period 2000-2006. Bilateral foreign direct investment (FDI) flows are almost never observed in the absence of bilateral trade flows, thus configuring an order of trade and investment flows. I document a similar pattern using bilateral foreign affiliate sales (FAS), aggregating them up from a large firm level dataset (ORBIS), which includes over 45,000 firms. I propose a model where heterogeneous firms face a proximity-concentration tradeoff when they decide whether to serve foreign markets through export or FDI. I derive theory-based gravity-type equations for the aggregate bilateral trade and foreign affiliate sales (FAS) flows. I then suggest a two-stage estimation procedure. In the first stage, a ordered Probit model is used to retrieve consistent estimates of the terms needed to correct the flows equations for heterogeneity and selection. In the second stage, a maximum likelihood estimator is applied to the corrected trade and FAS equations. The main results of the analysis are as follows: 1) The impact of distance, border and regional trade agreements on bilateral foreign affiliate sales becomes substantially smaller after controlling for selection and firms' heterogeneity (hence separating the impact on the extensive versus the intensive margin). 2) The same ``attenuation'' result is found also for the trade equations, consistently with HMR. 3) When FAS are observed, failing to take this into account when correcting for heterogeneity and selection in the trade equations leads to differences in the estimated coefficients. The third essay is titled ``Some Evidence on the Importance of Sticky Wages'', and is co-authored with Susanto Basu and Peter Gottshalk. Nominal wage stickiness is an important component of recent medium-scale structural macroeconomic models, but to date there has been little microeconomic evidence supporting the assumption of sluggish nominal wage adjustment. We present evidence on the frequency of nominal wage adjustment using data from the Survey of Income and Program Participation (SIPP) for the period 1996-1999. The SIPP provides high-frequency information on wages, employment and demographic characteristics for a large and representative sample of the US population. The main results of the analysis are as follows. 1) After correcting for measurement error, wages appear to be very sticky. In the average quarter, the probability that an individual will experience a nominal wage change is between 5 and 18 percent, depending on the samples and assumptions used. 2) The frequency of wage adjustment does not display significant seasonal patterns. 3) There is little heterogeneity in the frequency of wage adjustment across industries and occupations 4) The hazard of a nominal wage change first increases and then decreases, with a peak at 12 months. 5) The probability of a wage change is positively correlated with the unemployment rate and with the consumer price inflation rate. To a certain extent, the three essays presented here are self-contained and deal with three different issues regarding international economics and macroeconomics. Going to a deeper level, however, the essays are linked by a common feature: they are three examples of economic research across fields. The first essay, in fact, is an example of the growing fields at the edge between international trade and international macroeconomics. While the trade of goods and services and the dynamics of macroeconomic variables such as the current account are highly interconnected in the real world, these two fields have been characterized by a large divide in the last thirty years in the economic literature. The second essay is an example of a joint study of international trade and investment flows. Also in this case, while conceptually clearly interconnected, these topics have been usually studied separately by the economic literature. Finally, the third essay is an example of research across fields (labor economics and macroeconomics) and techniques (micro-level analysis informing macroeconomic models). In this last case, macroeconomists were interested in estimating certain wage dynamics parameters highly used in macro models. However, they were largely unaware of the fact that labor economists had the data to answer those research questions. On the other hand, the labor economists had the data, but not the questions. I hope that these essays might help increasing further the awareness that more communication between economists working in different fields can bring to valuable insights. / Thesis (PhD) — Boston College, 2011. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Economics.
7

Desequilíbrios cromossômicos em nove casos de osteossarcoma detectados através de hibridação genômica comparativa (CGH) / Chromosomal imbalances in nine cases of osteosarcoma detected by comparative genome hybridization (CGH)

Gamero, Angel Mauricio Castro 30 October 2008 (has links)
O osteossarcoma (OS) é o tumor ósseo maligno mais freqüente da infância e adolescência com uma taxa de sobrevida livre de eventos de 50 70% após 3 anos.. O pico de incidência ocorre na segunda década da vida, característica que sugere uma relação entre o rápido crescimento ósseo da adolescência e o desenvolvimento da neoplasia. Ainda, o conhecimento das bases genéticas é insuficiente. Estudos de citogenética clássica têm demonstrado que o OS caracteriza-se por exibir alta heterogeneidade cariotípica, incluindo altos graus de aneuploidia e rearranjos estruturais complexos. A técnica de CGH constitui uma ferramenta valiosa na analise do perfil genômico de tumores sólidos, e tem confirmado a complexidade das alterações cariotípicas em OS, descrita pela citogenética convencional. Não obstante, os estudos existentes são divergentes, e poucos têm estudado as informações obtidas por CGH em relação com a progressão tumoral. O objetivo do presente estudo foi identificar a presença de desequilíbrios cromossômicos em amostras de OS por meio da técnica de CGH. Os experimentos de CGH foram realizados de acordo com o descrito por Kallioniemi et al (1994). Foram analisadas nove amostras (3 biópsias, 5 ixressecções após quimioterapia e 1 metástase). O CGH detectou desequilíbrios cromossômicos em todas as amostras. Os ganhos foram mais freqüentes que as perdas. Muitas alterações cromossômicas foram observadas, especialmente ganhos nos cromossomos 1q, 2, 3p, 4, 5p, 6, 7, 8, 11p, 14q, 16, 21q e X; e perdas nos cromossomos 1p, 2q, 3q, 5q, 9q, 11q e 17q. As regiões mínimas de sobreposição mais freqüentes foram ganhos de 2p13-p14, 2q36-q37, 4q21 e 8p22, e perdas de 1p34.2, 3q22-q23 e 3q24. Três pacientes apresentaram amostras pareadas, e as alterações cromossômicas detectadas foram muito variadas, refletindo a heterogeneidade cromossômica intratumoral em cada caso. A mais alta divergência clonal entre as amostras pareadas foi observada entre a amostra de ressecção e a amostra metastática correspondente, mostrando a complexidade cromossômica adquirida durante a progressão e metastatização no caso descrito. Ainda são necessárias investigações adicionais, que contribuíam para a caracterização completa dos genes localizados nessas regiões. / Osteosarcoma (OS) is the most frequent aggressive bone malignancy affecting children and young adults with an event-free survival of 50-70% after 3 years. The incidence peak occurs during the second decade of life, suggesting a relationship between rapid bone growth and the development of this tumor. The knowledge of the genetic basis behind tumor progression is still limited. Conventional cytogenetic studies have demonstrated that OS exhibits high cariotipic heterogeneity, with different degrees of aneuploidy and complex structural rearrangements. The CGH is an important tool for studying the genomic profiles of solid tumors, and has confirmed the complexity of cariotipic alterations in OS. However, previous studies have shown divergent results and few have correlated them with tumor progression. The objective of present study was to identify chromosome unbalances in nine samples of OS by CGH. 3 biopsies, 5 resections before quimioterapy and 1 metastasis were analyzed. The experiments were performed accordingly with Kallioniemi et al (1994). CGH detected chromosomal imbalances in all samples. Gains were more frequent than losses. Many chromosomal alterations were observed, especially gains at 1q, xi2, 3p, 4, 5p, 6, 7, 8, 11p, 14q, 16, 21q and X; and losses at 1p, 2q, 3q, 5q, 9q, 11q and 17q. The minimal regions of superposition were gains of 2p13-p14, 2q36-q37, 4q21 and 8p22, and losses of 1p43.2, 3q22-q23 and 3q24. Three patients had consecutive samples, and the chromosomal alterations varied, reflecting the chromosomal heterogeneity for each case. The highest clonal divergence among the consecutive samples was observed between resection and the corresponding metastatic sample, showing the chromosomal complexity acquired during the progression and dissemination in this case. Additional investigations for the characterization of genes at these regions are necessary.
8

Organizational structure of ocean carriers in Central Europe and related benefits and problems / Container imbalances in Central Europe

Schaper, Teemu January 2012 (has links)
This thesis provides a description of the market for maritime container transport with a focus on container imbalances in Central Europe. Based on secondary literature, statistics and interviews, the current situation of global maritime trade and existing challenges for shipping lines is presented. In the second part, particular characteristics of the Central European market are introduced. Besides a detailed description of the infrastructure for container transports to and from this region, challenges and strategies considered by shipping lines are presented. It is highlighted that the export orientation of Germany and Austria and the import orientation of the Czech Republic and Slovakia have certain implications for the regional transport market. A real-life business case highlights existing problems, especially connected to the internal setup of ocean carriers which do not exploit all potentials of cross-border cooperation.
9

Potassium replacement in open heart surgical patients

Miller, Kenneth Peter January 1980 (has links)
No description available.
10

Desequilíbrios cromossômicos em nove casos de osteossarcoma detectados através de hibridação genômica comparativa (CGH) / Chromosomal imbalances in nine cases of osteosarcoma detected by comparative genome hybridization (CGH)

Angel Mauricio Castro Gamero 30 October 2008 (has links)
O osteossarcoma (OS) é o tumor ósseo maligno mais freqüente da infância e adolescência com uma taxa de sobrevida livre de eventos de 50 70% após 3 anos.. O pico de incidência ocorre na segunda década da vida, característica que sugere uma relação entre o rápido crescimento ósseo da adolescência e o desenvolvimento da neoplasia. Ainda, o conhecimento das bases genéticas é insuficiente. Estudos de citogenética clássica têm demonstrado que o OS caracteriza-se por exibir alta heterogeneidade cariotípica, incluindo altos graus de aneuploidia e rearranjos estruturais complexos. A técnica de CGH constitui uma ferramenta valiosa na analise do perfil genômico de tumores sólidos, e tem confirmado a complexidade das alterações cariotípicas em OS, descrita pela citogenética convencional. Não obstante, os estudos existentes são divergentes, e poucos têm estudado as informações obtidas por CGH em relação com a progressão tumoral. O objetivo do presente estudo foi identificar a presença de desequilíbrios cromossômicos em amostras de OS por meio da técnica de CGH. Os experimentos de CGH foram realizados de acordo com o descrito por Kallioniemi et al (1994). Foram analisadas nove amostras (3 biópsias, 5 ixressecções após quimioterapia e 1 metástase). O CGH detectou desequilíbrios cromossômicos em todas as amostras. Os ganhos foram mais freqüentes que as perdas. Muitas alterações cromossômicas foram observadas, especialmente ganhos nos cromossomos 1q, 2, 3p, 4, 5p, 6, 7, 8, 11p, 14q, 16, 21q e X; e perdas nos cromossomos 1p, 2q, 3q, 5q, 9q, 11q e 17q. As regiões mínimas de sobreposição mais freqüentes foram ganhos de 2p13-p14, 2q36-q37, 4q21 e 8p22, e perdas de 1p34.2, 3q22-q23 e 3q24. Três pacientes apresentaram amostras pareadas, e as alterações cromossômicas detectadas foram muito variadas, refletindo a heterogeneidade cromossômica intratumoral em cada caso. A mais alta divergência clonal entre as amostras pareadas foi observada entre a amostra de ressecção e a amostra metastática correspondente, mostrando a complexidade cromossômica adquirida durante a progressão e metastatização no caso descrito. Ainda são necessárias investigações adicionais, que contribuíam para a caracterização completa dos genes localizados nessas regiões. / Osteosarcoma (OS) is the most frequent aggressive bone malignancy affecting children and young adults with an event-free survival of 50-70% after 3 years. The incidence peak occurs during the second decade of life, suggesting a relationship between rapid bone growth and the development of this tumor. The knowledge of the genetic basis behind tumor progression is still limited. Conventional cytogenetic studies have demonstrated that OS exhibits high cariotipic heterogeneity, with different degrees of aneuploidy and complex structural rearrangements. The CGH is an important tool for studying the genomic profiles of solid tumors, and has confirmed the complexity of cariotipic alterations in OS. However, previous studies have shown divergent results and few have correlated them with tumor progression. The objective of present study was to identify chromosome unbalances in nine samples of OS by CGH. 3 biopsies, 5 resections before quimioterapy and 1 metastasis were analyzed. The experiments were performed accordingly with Kallioniemi et al (1994). CGH detected chromosomal imbalances in all samples. Gains were more frequent than losses. Many chromosomal alterations were observed, especially gains at 1q, xi2, 3p, 4, 5p, 6, 7, 8, 11p, 14q, 16, 21q and X; and losses at 1p, 2q, 3q, 5q, 9q, 11q and 17q. The minimal regions of superposition were gains of 2p13-p14, 2q36-q37, 4q21 and 8p22, and losses of 1p43.2, 3q22-q23 and 3q24. Three patients had consecutive samples, and the chromosomal alterations varied, reflecting the chromosomal heterogeneity for each case. The highest clonal divergence among the consecutive samples was observed between resection and the corresponding metastatic sample, showing the chromosomal complexity acquired during the progression and dissemination in this case. Additional investigations for the characterization of genes at these regions are necessary.

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