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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

Gene expression profiling of chickpea responses to drought, cold and high-salinity using cDNA microarray

Mantri, Nitin Laxminarayan, nitin_mantri@rediffmail.com January 2007 (has links)
Cultivated chickpea (Cicer arietinum) has a narrow genetic base making it difficult for breeders to produce new elite cultivars with durable resistance to major biotic and abiotic stresses. As an alternative to genome mapping, microarrays have recently been applied in crop species to identify and assess the function of putative genes thought to be involved in plant abiotic stress and defence responses. In the present study, a cDNA microarray approach was taken in order to determine if the transcription of genes, from a set of previously identified putative stress-responsive genes from chickpea and its close relative Lathyrus sativus, were altered in chickpea by the three abiotic stresses; drought, cold and high-salinity. For this, chickpea genotypes known to be tolerant and susceptible to each abiotic stress were challenged and gene expression in the leaf, root and/or flower tissues was studied. The transcripts that were differentially expressed among stressed an d unstressed plants in response to the particular stress were analysed in the context of tolerant/susceptible genotypes. The transcriptional change of more than two fold was observed for 109, 210 and 386 genes after drought, cold and high-salinity treatments, respectively. Among these, two, 15 and 30 genes were consensually differentially expressed (DE) between tolerant and susceptible genotypes studied for drought, cold and high-salinity, respectively. The genes that were DE in tolerant and susceptible genotypes under abiotic stresses code for various functional and regulatory proteins. Significant differences in stress responses were observed within and between tolerant and susceptible genotypes highlighting the multiple gene control and complexity of abiotic stress response mechanism in chickpea. The annotation of these genes suggests that they may have a role in abiotic stress response and are potential candidates for tolerance/susceptibility.
2

MEDIATION OF NICKEL-INDUCED ACUTE LUNG INJURY BY NITRIC OXIDE

McDowell, Susan Ann 11 October 2001 (has links)
No description available.
3

The identification of candidate genes using cDNA microarray and the analysis of two SNPs of the reelin gene in a South African austistic population

Hajirah Gameeldien January 2009 (has links)
<p>Autism is a pervasive developmental disorder (PDD) that&rsquo / s incidence is approximately 1 in 158. It is four times more prevalent in males than females and is believed to be caused by both genetic and environmental factors. Research indicates that several genes are involved in autism and it is believed that these genes act together to produce autism. Many genes implicated in this disorder are involved with brain structure formation and brain functioning. Studies have identified the reelin (RELN) gene as necessary for proper formation of brain, which indicates that RELN abnormalities could contribute to the aetiology of several neurogenetic diseases such as schizophrenia, bipolar and autism. The aims of the study were (i) to genotype two SNPs (exonic rs3622691 and intronic rs736707) in the RELN gene using Taqman&reg / SNP Genotyping assays to detect association with autism in three distinct South African (SA) ethnic groups (Black, Caucasian and Mixed), and (ii) to detect candidate genes that are over and under-expressed in the samples taken from a SA Caucasian autistic group and compare those with samples taken from a healthy Caucasian group using cDNA microarray. The Taqman&reg / study indicated significant association for the intronic SNP, rs736707, with a p-value of 0.0009 in the total SA group. More so, the Mixed group displayed the highest significance amongst the ethnic groups, with a p-value of 0.00014. The microarray study yielded 21 genes with 95% significance in the Caucasian sample group. Most genes were hypothetical proteins and formed part of the FAM90A family. The LOC83459 showed the highest level of expression in the autistic samples, while the BTNL8 gene was shown to be highly suppressed in the control samples.</p>
4

In vitro and in vivo analysis of differential gene expression between normal norfolk terrier dogs and those with an autosomal recessive mutation in KRT10

Barnhart, Kirstin Faye 01 November 2005 (has links)
Natural diseases caused by keratin mutations are rare and have only been reported in humans. We have recently identified a heritable skin disorder in Norfolk terriers caused by a mutation in KRT10. Affected dogs have a tendency to form shallow erosions or blisters following mild trauma, which is first noted after the birthing process. As the dogs age, they display generalized hyperpigmentation and scaling that is most severe in the axillary and inguinal regions. The main histologic and ultrastructural features include: marked hyperkeratosis, epidermal hyperplasia, prominent vacuolation of the upper suprabasal layers, eosinophilic intracytoplasmic aggregates (keratin bundles), numerous and frequently enlarged keratohyaline granules, and epidermal hyperplasia. Analysis of an extended pedigree through seven generations confirmed an autosomal recessive mode of inheritance. The keratin 10 mutation was defined as a G-T point mutation in intron 5 that affected splicing at the boundary of exon 4 and intron 5. The primary outcome of the mutation was a 35 bp deletion in exon 4 caused by use of a cryptic splice site. Real-time PCR quantitation of KRT10 confirmed that this mutation led to premature mRNA decay and an average 35-fold decrease in KRT10 message. Organotypic cell culture techniques were used to establish in vitro models for normal and affected Norfolk terriers. After 21 days of culture, normal epidermis was cornified with a compact and multifocally parakeratotic stratum corneum. Affected epidermis largely reproduced the expected morphologic alterations. Immunoblotting and immunohistochemistry for keratin 10 protein and real-time PCR quantitation of KRT10 message showed significantly less keratin expression in vitro than in vivo suggesting that the differentiation program in vitro underwent significant alterations. A diagnostic PCR assay was established for detection of the carrier state. Global analysis of gene expression between normal, carrier and affected dogs was performed with DermArray cDNA microarrays. Affected and carrier dogs showed differential regulation of 320 and 298 genes, respectively, between normal dogs. In affected dogs, 217 were upregulated and 103 were downregulated. In carrier dogs, 222 were upregulated and 76 were downregulated. 72 genes (65 upregulated, 7 downregulated) were altered in both affected and heterozygous dogs.
5

The identification of candidate genes using cDNA microarray and the analysis of two SNPs of the reelin gene in a South African austistic population

Hajirah Gameeldien January 2009 (has links)
<p>Autism is a pervasive developmental disorder (PDD) that&rsquo / s incidence is approximately 1 in 158. It is four times more prevalent in males than females and is believed to be caused by both genetic and environmental factors. Research indicates that several genes are involved in autism and it is believed that these genes act together to produce autism. Many genes implicated in this disorder are involved with brain structure formation and brain functioning. Studies have identified the reelin (RELN) gene as necessary for proper formation of brain, which indicates that RELN abnormalities could contribute to the aetiology of several neurogenetic diseases such as schizophrenia, bipolar and autism. The aims of the study were (i) to genotype two SNPs (exonic rs3622691 and intronic rs736707) in the RELN gene using Taqman&reg / SNP Genotyping assays to detect association with autism in three distinct South African (SA) ethnic groups (Black, Caucasian and Mixed), and (ii) to detect candidate genes that are over and under-expressed in the samples taken from a SA Caucasian autistic group and compare those with samples taken from a healthy Caucasian group using cDNA microarray. The Taqman&reg / study indicated significant association for the intronic SNP, rs736707, with a p-value of 0.0009 in the total SA group. More so, the Mixed group displayed the highest significance amongst the ethnic groups, with a p-value of 0.00014. The microarray study yielded 21 genes with 95% significance in the Caucasian sample group. Most genes were hypothetical proteins and formed part of the FAM90A family. The LOC83459 showed the highest level of expression in the autistic samples, while the BTNL8 gene was shown to be highly suppressed in the control samples.</p>
6

The identification of candidate genes using cDNA microarray and the analysis of two SNPs of the reelin gene in a South African austistic population

Gameeldien, Hajirah January 2009 (has links)
Magister Scientiae - MSc / Autism is a pervasive developmental disorder (PDD) that's incidence is approximately 1 in 158. It is four times more prevalent in males than females and is believed to be caused by both genetic and environmental factors. Research indicates that several genes are involved in autism and it is believed that these genes act together to produce autism. Many genes implicated in this disorder are involved with brain structure formation and brain functioning. Studies have identified the reelin (RELN) gene as necessary for proper formation of brain, which indicates that RELN abnormalities could contribute to the aetiology of several neurogenetic diseases such as schizophrenia, bipolar and autism. The aims of the study were (i) to genotype two SNPs (exonic rs3622691 and intronic rs736707) in the RELN gene using Taqman® SNP Genotyping assays to detect association with autism in three distinct South African (SA) ethnic groups (Black, Caucasian and Mixed), and (ii) to detect candidate genes that are over and under-expressed in the samples taken from a SA Caucasian autistic group and compare those with samples taken from a healthy Caucasian group using cDNA microarray. The Taqman® study indicated significant association for the intronic SNP, rs736707, with a p-value of 0.0009 in the total SA group. More so, the Mixed group displayed the highest significance amongst the ethnic groups, with a p-value of 0.00014. The microarray study yielded 21 genes with 95% significance in the Caucasian sample group. Most genes were hypothetical proteins and formed part of the FAM90A family. The LOC83459 showed the highest level of expression in the autistic samples, while the BTNL8 gene was shown to be highly suppressed in the control samples. / South Africa
7

Estudo da expressão das proteínas TFE3 e receptor de insulina nos hepatoblastomas a partir dos achados de expressão gênica / Effectiveness of auditory training through evoked potentials to complex sound in hearing and language disorders

Filippi, Renée Zon 10 November 2011 (has links)
O hepatoblastoma é uma neoplasia embrionária hepática que ocorre na faixa pediátrica, rara, sendo bastante heterogênea devido aos seus diferentes componentes epiteliais e mesenquimais. Pouco ainda se sabe a respeito de sua patogênese. Utilizando um microscópio de captura a laser foram dissecadas áreas de componente epitelial do hepatoblastoma e áreas de tecido hepático adjacente não acometido. Destas amostras obtidas de pacientes não submetidos ao tratamento prévio, foram extraídos RNA e confeccionados cDNA microarrays, para análise comparativa da expressão gênica, seguida de validação por método imunohistoquímico de alguns genes selecionados. Comparando neoplasia e tecido hepático em duas amostras criopreservadas foram identificados 70 genes diferencialmente expressos, sendo 19 hiperexpressos e 51 hipoexpressos no tumor. A maioria dos genes encontrados foi mapeada nos cromossomos 1 e 2. Dos genes selecionados para validação por método imuno-histoquímico, destacaram-se o receptor de Insulina e o TFE3 (genes hipoexpressos no cDNA microarray). A imunomarcação para o receptor de insulina foi positiva tanto no tecido hepático não acometido quanto no componente epitelial fetal do hepatoblastoma , mas foi consistentemente negativa nas amostras de componente embrionário (9/9). A imunomarcação para o TFE3 foi positiva no tecido hepático não acometido, e nos componentes epitelial fetal e embrionário, em proporção variável das células com expressão mais intensa no componente embrionário. As reações imuno-histoquímicas para os outros genes selecionados não permitiram interpretação conclusiva. A alta proporção dos genes diferencialmente expressos localizados nos cromossomos 1 e 2 reflete os achados citogenéticos relatados na literatura relacionada ao hepatoblastoma . Achados de imunoexpressão de proteínas relacionadas aos genes TFE3 e receptor de insulina no tecido hepático e nos diferentes componentes do hepatoblastoma são inéditos e sugerem participação da via sinalizadora da insulina na patogênese destes tumores / Hepatoblastoma is a rare tumor, and little is known about its pathogenesis and genetic alterations. Using a laser capture microdissection microscope we sampled areas of epithelial component of hepatoblastoma prior chemotherapy and their normal liver counterpart in order to perform the comparative gene expression analysis followed by the validation of selected genes by immunohistochemistry. Comparing tumor and non-diseased liver in two frozen samples, 70 differentially expressed genes were found, 19 overexpressed and 51 underexpressed in the tumor. Most of the genes were located at chromosomes 1 and 2. Of the genes selected for validation by immunohistochemistry, the most interesting findings came from Insulin receptor and TFE3 (both underexpressed genes). Insulin receptor was positive in non diseased liver and in the fetal component of the Hepatoblastoma but was consistently negative in the embryonal component (9/9 cases). The TFE3 staining was positive in the normal liver and fetal and embryonal components of the tumor in variable proportion of the cells, more marked in the embryonal component. The higher proportion of genes located at chromosomes 1 and 2 corroborates the cytogenetics findings reported in the literature related to Hepatoblastoma . The immunohistochemistry findings of different expression of insulin receptor in the fetal and embryonal components of Hepatoblastoma and the positivity of TFE3 in normal liver and in the tumors epithelial components deserves further investigation regarding the role of these genes to the pathogenesis of Hepatoblastoma
8

Avaliação do perfil de expressão gênica em grande escala de células indiferenciadas da polpa e de células odontoblásticas utilizando cDNA microarray / Evaluation of large scale gene expression profile of undifferentiated pulp cells and odontoblastic cells using cDNA microarray

Ferreira, Maidy Rehder Wimmers 11 May 2011 (has links)
O extraordinário potencial regenerativo do complexo dentino-pulpar enfatiza a importância da caracterização dos processos celulares e moleculares envolvidos na regeneração dentinária. O avanço da pesquisa com células-tronco desencadeou um grande interesse de cultivá-las na presença de sinais de indução odontogênica. O objetivo do presente trabalho foi avaliar comparativamente células indiferenciadas da polpa (OD-21) e odontoblásticas (MDPC-23) através da avaliação do estímulo celular e do perfil de expressão gênica. As células OD-21 e MDPC-23 foram cultivadas em garrafas de cultura até a subconfluência e, em seguida, cultivadas em placas de 24 poços na concentração de 104 células /poço (n = 5). Os parâmetros analisados foram: (1) proliferação, viabilidade celular e atividade de fosfatase alcalina após 3, 7 e 10 dias; além de detecção e quantificação de matriz mineralizada após 17 dias (o teste estatístico utilizado foi o de Mann-Whitney para p&le;0,05); (2) imunofluorescência para proteínas não-colágenas (DSPP e osteopontina) após 1, 3 e 7 dias; (3) análises de expressão transcricional através da tecnologia de cDNA microarray e PCR em tempo real. Os dados de microarrays foram analisados com o auxílio de programas de bioinformática especializados como SAM (significance analysis of microarrays), Cluster-TreeView e GeneNetwork. A expressão gênica foi avalidada pela reação em tempo real em cadeia da polimerase (PCR). Os resultados mostraram que a viabilidade celular ficou acima dos 80% em ambas as células, e que a proliferação celular e a atividade de fosfatase alcalina foram maiores nas células MDPC-23. Foram observados nódulos de mineralização somente na cultura de células odontoblásticas. A osteopontina apresentou-se igualmente presente em ambas as células, enquanto a sialofosfoproteína dentinária foi expressa em maior quantidade nas células MDPC-23. Os resultados demonstraram genes com comportamento semelhante nos dois tipos de células, tais como Bad (morte celular), Erf e Btg1 (proliferação celular), Cxcl10 e Il13 (resposta imune) e Arfgef1 (comunicação celular). Além disso, regiões no heatmap mostraram diferenças na indução e repressão de genes, como C1qb (resposta imune), Jak2 (morte, comunicação e proliferação celular), Col4a1 (adesão celular), Rpl6 e Rpl26 (processo metabólico celular). Concluímos que as células OD-21, embora indiferenciadas, compartilham muitos genes com comportamento semelhante à células odontoblásticas MDPC-23, sugerindo seu potencial para se diferenciar em odontoblastos. / The extraordinary regenerative potential of pulp-dentin complex leads to the importance of the characterization of cell and molecular processes involved in regeneration of dentin. The advancement of stem cell research sparked great interest in cultivating them in the presence of signs of odontogenic induction. The purpose of the present investigation was to evaluate comparatively undifferentiated pulp cells (OD-21) and odontoblastic cells (MDPC-23) through the assessment of cell stimulation and gene expression profiling. OD-21 and MDPC-23 cells were grown in culture flasks until subconfluence, and then cultured in 24-well plates at a concentration of 104 cells/well (n=5). The parameters analyzed were: (1) proliferation, cell viability and alkaline phosphatase activity after 3, 7 and 10 days, in addition to detection and quantification of mineralized matrix after 17 days (the statistical test used was the Mann-Whitney p&le;0.05), (2) immunofluorescence for non-collagen proteins (DSPP and osteopontin) at 1, 3 and 7 days, (3) transcriptional expression analysis using cDNA microarray technology and real-time PCR. The microarray data were analyzed with the aid of specialized bioinformatics programs such as SAM (significance analysis of microarrays), Cluster, TreeView and GeneNetwork. Gene expression was avalided by real-time polymerase chain reaction (PCR). The results showed that cell viability was above 80% in both cells, and cell proliferation and alkaline phosphatase activity were higher in MDPC-23 cells. Mineralization nodules were observed only in the odontoblastic cell cultures. Osteopontin was present equally in both cells, whereas dentin sialophosphoprotein was higher expressed in MDPC-23 cells. The results showed genes with similar behavior in two cell types, such as Bad (cell death), Erf and Btg1 (cell proliferation), Il13 and Cxcl10 (immune response) and Arfgef1 (cell communication). Moreover, regions of the heatmap showed differences in induction and repression of genes, such C1qb (immune response), Jak2 (death, communication and cell proliferation), Col4a1 (cell adhesion), Rpl26 and Rpl6 (cellular metabolic process). We conclude that the OD-21 cells, although undifferentiated, share many genes with similar behavior to the odontoblastic MDPC-23 cells, suggesting their potential to differentiate into odontoblasts.
9

Avaliação do perfil de expressão gênica em grande escala de células indiferenciadas da polpa e de células odontoblásticas utilizando cDNA microarray / Evaluation of large scale gene expression profile of undifferentiated pulp cells and odontoblastic cells using cDNA microarray

Maidy Rehder Wimmers Ferreira 11 May 2011 (has links)
O extraordinário potencial regenerativo do complexo dentino-pulpar enfatiza a importância da caracterização dos processos celulares e moleculares envolvidos na regeneração dentinária. O avanço da pesquisa com células-tronco desencadeou um grande interesse de cultivá-las na presença de sinais de indução odontogênica. O objetivo do presente trabalho foi avaliar comparativamente células indiferenciadas da polpa (OD-21) e odontoblásticas (MDPC-23) através da avaliação do estímulo celular e do perfil de expressão gênica. As células OD-21 e MDPC-23 foram cultivadas em garrafas de cultura até a subconfluência e, em seguida, cultivadas em placas de 24 poços na concentração de 104 células /poço (n = 5). Os parâmetros analisados foram: (1) proliferação, viabilidade celular e atividade de fosfatase alcalina após 3, 7 e 10 dias; além de detecção e quantificação de matriz mineralizada após 17 dias (o teste estatístico utilizado foi o de Mann-Whitney para p&le;0,05); (2) imunofluorescência para proteínas não-colágenas (DSPP e osteopontina) após 1, 3 e 7 dias; (3) análises de expressão transcricional através da tecnologia de cDNA microarray e PCR em tempo real. Os dados de microarrays foram analisados com o auxílio de programas de bioinformática especializados como SAM (significance analysis of microarrays), Cluster-TreeView e GeneNetwork. A expressão gênica foi avalidada pela reação em tempo real em cadeia da polimerase (PCR). Os resultados mostraram que a viabilidade celular ficou acima dos 80% em ambas as células, e que a proliferação celular e a atividade de fosfatase alcalina foram maiores nas células MDPC-23. Foram observados nódulos de mineralização somente na cultura de células odontoblásticas. A osteopontina apresentou-se igualmente presente em ambas as células, enquanto a sialofosfoproteína dentinária foi expressa em maior quantidade nas células MDPC-23. Os resultados demonstraram genes com comportamento semelhante nos dois tipos de células, tais como Bad (morte celular), Erf e Btg1 (proliferação celular), Cxcl10 e Il13 (resposta imune) e Arfgef1 (comunicação celular). Além disso, regiões no heatmap mostraram diferenças na indução e repressão de genes, como C1qb (resposta imune), Jak2 (morte, comunicação e proliferação celular), Col4a1 (adesão celular), Rpl6 e Rpl26 (processo metabólico celular). Concluímos que as células OD-21, embora indiferenciadas, compartilham muitos genes com comportamento semelhante à células odontoblásticas MDPC-23, sugerindo seu potencial para se diferenciar em odontoblastos. / The extraordinary regenerative potential of pulp-dentin complex leads to the importance of the characterization of cell and molecular processes involved in regeneration of dentin. The advancement of stem cell research sparked great interest in cultivating them in the presence of signs of odontogenic induction. The purpose of the present investigation was to evaluate comparatively undifferentiated pulp cells (OD-21) and odontoblastic cells (MDPC-23) through the assessment of cell stimulation and gene expression profiling. OD-21 and MDPC-23 cells were grown in culture flasks until subconfluence, and then cultured in 24-well plates at a concentration of 104 cells/well (n=5). The parameters analyzed were: (1) proliferation, cell viability and alkaline phosphatase activity after 3, 7 and 10 days, in addition to detection and quantification of mineralized matrix after 17 days (the statistical test used was the Mann-Whitney p&le;0.05), (2) immunofluorescence for non-collagen proteins (DSPP and osteopontin) at 1, 3 and 7 days, (3) transcriptional expression analysis using cDNA microarray technology and real-time PCR. The microarray data were analyzed with the aid of specialized bioinformatics programs such as SAM (significance analysis of microarrays), Cluster, TreeView and GeneNetwork. Gene expression was avalided by real-time polymerase chain reaction (PCR). The results showed that cell viability was above 80% in both cells, and cell proliferation and alkaline phosphatase activity were higher in MDPC-23 cells. Mineralization nodules were observed only in the odontoblastic cell cultures. Osteopontin was present equally in both cells, whereas dentin sialophosphoprotein was higher expressed in MDPC-23 cells. The results showed genes with similar behavior in two cell types, such as Bad (cell death), Erf and Btg1 (cell proliferation), Il13 and Cxcl10 (immune response) and Arfgef1 (cell communication). Moreover, regions of the heatmap showed differences in induction and repression of genes, such C1qb (immune response), Jak2 (death, communication and cell proliferation), Col4a1 (cell adhesion), Rpl26 and Rpl6 (cellular metabolic process). We conclude that the OD-21 cells, although undifferentiated, share many genes with similar behavior to the odontoblastic MDPC-23 cells, suggesting their potential to differentiate into odontoblasts.
10

Estudo da expressão das proteínas TFE3 e receptor de insulina nos hepatoblastomas a partir dos achados de expressão gênica / Effectiveness of auditory training through evoked potentials to complex sound in hearing and language disorders

Renée Zon Filippi 10 November 2011 (has links)
O hepatoblastoma é uma neoplasia embrionária hepática que ocorre na faixa pediátrica, rara, sendo bastante heterogênea devido aos seus diferentes componentes epiteliais e mesenquimais. Pouco ainda se sabe a respeito de sua patogênese. Utilizando um microscópio de captura a laser foram dissecadas áreas de componente epitelial do hepatoblastoma e áreas de tecido hepático adjacente não acometido. Destas amostras obtidas de pacientes não submetidos ao tratamento prévio, foram extraídos RNA e confeccionados cDNA microarrays, para análise comparativa da expressão gênica, seguida de validação por método imunohistoquímico de alguns genes selecionados. Comparando neoplasia e tecido hepático em duas amostras criopreservadas foram identificados 70 genes diferencialmente expressos, sendo 19 hiperexpressos e 51 hipoexpressos no tumor. A maioria dos genes encontrados foi mapeada nos cromossomos 1 e 2. Dos genes selecionados para validação por método imuno-histoquímico, destacaram-se o receptor de Insulina e o TFE3 (genes hipoexpressos no cDNA microarray). A imunomarcação para o receptor de insulina foi positiva tanto no tecido hepático não acometido quanto no componente epitelial fetal do hepatoblastoma , mas foi consistentemente negativa nas amostras de componente embrionário (9/9). A imunomarcação para o TFE3 foi positiva no tecido hepático não acometido, e nos componentes epitelial fetal e embrionário, em proporção variável das células com expressão mais intensa no componente embrionário. As reações imuno-histoquímicas para os outros genes selecionados não permitiram interpretação conclusiva. A alta proporção dos genes diferencialmente expressos localizados nos cromossomos 1 e 2 reflete os achados citogenéticos relatados na literatura relacionada ao hepatoblastoma . Achados de imunoexpressão de proteínas relacionadas aos genes TFE3 e receptor de insulina no tecido hepático e nos diferentes componentes do hepatoblastoma são inéditos e sugerem participação da via sinalizadora da insulina na patogênese destes tumores / Hepatoblastoma is a rare tumor, and little is known about its pathogenesis and genetic alterations. Using a laser capture microdissection microscope we sampled areas of epithelial component of hepatoblastoma prior chemotherapy and their normal liver counterpart in order to perform the comparative gene expression analysis followed by the validation of selected genes by immunohistochemistry. Comparing tumor and non-diseased liver in two frozen samples, 70 differentially expressed genes were found, 19 overexpressed and 51 underexpressed in the tumor. Most of the genes were located at chromosomes 1 and 2. Of the genes selected for validation by immunohistochemistry, the most interesting findings came from Insulin receptor and TFE3 (both underexpressed genes). Insulin receptor was positive in non diseased liver and in the fetal component of the Hepatoblastoma but was consistently negative in the embryonal component (9/9 cases). The TFE3 staining was positive in the normal liver and fetal and embryonal components of the tumor in variable proportion of the cells, more marked in the embryonal component. The higher proportion of genes located at chromosomes 1 and 2 corroborates the cytogenetics findings reported in the literature related to Hepatoblastoma . The immunohistochemistry findings of different expression of insulin receptor in the fetal and embryonal components of Hepatoblastoma and the positivity of TFE3 in normal liver and in the tumors epithelial components deserves further investigation regarding the role of these genes to the pathogenesis of Hepatoblastoma

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