Navegando por Palavras-chave "Chromosomes"
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- ItemAcesso aberto (Open Access)Análise citogenética de escorpiões da fauna brasileira com ênfase nas sequências de DNA repetitivo(Universidade Federal de São Paulo, 2017-03-24) Lima, Juliana Figueiredo de [UNIFESP]; Schneider, Marielle Cristina [UNIFESP]; Universidade Federal de São Paulo (UNIFESP)In this work, 10 scorpions species were analyzed analyzed, aiming to understand processes involved in the origin and maintenance of interspecific and intraspecific chromosomal variability and the mechanisms related to the high rates of chromosomal rearrangements. To this end, species of the families Buthidae and Chactidae, which have differences in relation to the type of chromosomes and the presence / absence of rearrangements, were cytogenetically characterized regarding to the distribution and amount of heterochromatin and repetitive DNA sequences (multigenic families and / or satellite DNA). The study of bisexual populations of T. serrulatus revealed a diploid number (2n = 12) similar to that previously described for parthenogenetic populations. However, the identification of specific chromosomal region (28S rDNA) showed differences between males and females, which presented, respectively, two and one chromosomes carrying the ribosomal gene. This result points to the presence of a ZZ / ZW sex chromosome system in this species. The analysis of nine other scorpions of the families Chactidae and Buthidae showed that in the cactids the diploid numbers are higher (2n = 50, 2n = 36 and 2n = 30) than in the buthids (2n = 6, 2n = 10, 2n = 14, 2n = 18, 2n = 26) and that the species have monocentric chromosomes. Despite the differences in diploid number, the localization of rDNA sites were conserved in the species Brotheas amazonicus and Chactopsis amazonica (Chactidae) and Tityus apiacas (Buthidae). The localization of repetitive sequences through the Cot-1 technique and constitutive heterochromatin by C-band and DAPI-after FISH indicate that there is no a frequent of repetitive DNA distribution in the chromosomes. This data reveals that the identification of repetitive DNA sequences in scorpion chromosomes need to be analyzed with different cytogenetic approaches. In addition, a more comprehensive knowledge of the quantity and types of repetitive sequences present in the genome of scorpions is needed to ascertain whether there is a relationship between the occurrence of these regions with rates of chromosomal rearrangement found in the species.
- ItemSomente MetadadadosInvestigação genética e citogenética molecular em osteossarcomas(Universidade Federal de São Paulo (UNIFESP), 2002) Toledo, Silvia Regina Caminada de [UNIFESP]; Andrade, Joyce Anderson Duffles [UNIFESP]O osteossarcoma (OS) e um tumor osseo maligno, derivado do mesenquima primitivo e entre os tumores osseos e o que apresenta maior incidencia em adolescentes.0 pico de ocorrencia e a segunda decada de vida, acometendo com maior frequencia sitios de crescimento rapido, durante o estirao de crescimento. 0 interesse na patologia e biologia do OS tem aumentado consideravelmente, uma vez que entre os tumores solidos da infancia e adolescencia e exemplo proeminente da eficacia do tratamento quimioterapico agressivo. 0 conhecimento dos eventos geneticos relacionados com a genese e os mecanismos de resistencia a drogas desses tumores contribuem para um melhor entendimento da biologia do OS. 0 presente trabalho teve os seguintes objetivos: 1.Investigar a expressao de genes que possam estar envolvidos na resistencia a drogas no OS, na tentativa de contribuir para o conhecimento desse complexo mecanismo. 2. Avaliar as regioes de perda elou ganho de material cromossomico em OS por meio de hibridacao genomica comparativa (CGH).3. Investigar comparativamente, em linhagens celulares de OS a instabilidade cromossomica, avaliada por meio de hibridacao in situ fuorescente (FISH) e os dados de ganho e/ou perda de material cromossomico obtidos por CGH. Nos investigamos o gene de resistencia a multiplas drogas (MDR1), o proto-oncogene ERBB2 e um gene associado a resistencia a cisplatina (CRAb). A relacao entre a expressao do gene MDR1, resposta a quimioterapia e recaida da doenca ainda permanece controversa. A expressao da proteina erbb2 tem sido relacionada a mau prognostico e a proposta e utilizar essa proteina como alvo terapeutico em OS. 0 produto do gene CRAb foi associado a resistencia a cisplatina, porem sem nenhuma investigacao anterior descrita na literatura. Foram estudadas 26 amostras de 20 pacientes portadores de OS e uma amostra de osso normal sem evidencia clinica de doenca ossea. A estrategia de investigacao utilizada foi a combinacao de transcricao reversa - reacao em cadeia da polimerase (RT-PCR). 0 gene MDR1 foi investigado em 24 samples, 63 por cento positivo para a expressao do gene (5 amostras pre-quimioterapia e 10 amostras pos-quimioterapia). 0 gene CRAb foi investigado em 23 amostras, 57 por cento foram positivas (6 amostras pre-quimioterapia e 7 pos-quimioterapia). 0 gene ERBB2 foi investigado em 21 amostras, somente uma teve... (au)
- ItemAcesso aberto (Open Access)Síndrome da deleção do braço curto do cromossomo 18: avaliação clínica e citogenômica(Universidade Federal de São Paulo (UNIFESP), 2016-03-30) Meloni, Vera de Freitas Ayres [UNIFESP]; Melaragno, Maria Isabel de Souza Aranha [UNIFESP]; http://lattes.cnpq.br/0678071850781758; http://lattes.cnpq.br/4404095921360586; Universidade Federal de São Paulo (UNIFESP)Chromosome 18p deletion syndrome [del(18p)] (OMIM 146390) has been well described in the literature with over 300 patients reported on, but few of them evaluated by cytogenomic techniques. Objective: We studied 12 patients with 18p deletion based on clinical, developmental and cytogenomic findings. Methods: The patients were evaluated by a specific clinical protocol, including immunological, endocrinological and neuropsychological assessments. The cytogenetic study was performed by G-banding karyotype, SNP-array (Genome-Wide Human SNP Array 6.0, Affymetrix) and FISH-BAC techniques. Results: A total of 12 patients, seven males and five females, previously diagnosed with 18p deletion were evaluated. The patients were classified in three groups according to the cytogenomic findings, as follows: five with pure 18p deletion (group I), two with ring chromosome 18 (group II) and five with 18p deletion associated with duplication or deletion of another chromosome (group III). Conclusions: The results showed a wide variation in intra- and inter-chromosomal rearrangements in patients, both inherited as de novo, as well as a wide variability of phenotypic manifestations and comorbidities. Although the literature indicates 18p11.1 as the most frequent breakpoint, our patients presented different breakpoints: 18p11.21 (5/12), 18p11.23 (2/12), 18p11.31 (4/12), and 18p11.32 (1/12). The main clinical findings were: proportionate short stature; microcephaly; ectopic pituitary; growth hormone deficiency; hypothyroidism; intellectual disability; cardiac anomalies; scoliosis; and keratosis pilaris. The distinguished facial dysmorphic features were: ocular hypertelorism; ptosis; and strabismus.The neuropsychological assessments showed IQ scores from borderline intellectual functioning to moderate intellectual disability. The SNP-array technique permitted a better chromosome breakpoint definition and, associated to the specific clinical protocol, provided a better genotype-phenotype correlation revealing genes that might influence the patient?s phenotype. Some genes located in the 18p deleted segment seem to play important roles in the patient?s phenotype, such as TGIF1, GNAL, LAMA1 and LPIN2 genes. The clinical protocol associated with cytogenomic results provided the recognition of relevant genes to the clinical manifestations found, such as holoprosencephaly microforms, keratosis pilaris, cryptorchidism, scoliosis and IgA deficiency. In addition, the multidisciplinary approach of this study allowed making recommendations for medical and neuropsychological evaluation on 18p deletion patients for better clinical monitoring and appropriate genetic counseling for each family.