Bleomycin sensitivity in patients with familial and sporadic polyposis: a pilot study

Human peripheral blood lymphocytes from 10 patients with familial adenomatous polyposis (FAP) showed a significantly higher incidence of chromatid breaks when compared to cells from 10 normal individuals, after exposure to bleomycin (BLM) during the G2 phase. However, no significant increase in bleomycin sensitivity was observed in lymphocytes from 10 patients with sporadic adenomatous polyps (AP) vs. 10 normal individuals (P = 0.67). Individuals that exhibited an average number of chromatid breaks per cell higher than 0.80 were considered sensitive to the drug. No control showed susceptibility to BLM, as compared to 3 out of 20 patients.<br>Inúmeros estudos têm mostrado que fibroblastos de pacientes com adenomatose hereditária de cólon e reto, que inclui polipose adenomatosa familial (FAP) e a síndrome de Gardner, apresentam uma freqüência aumentada de aberrações cromossômicas após exposição a agentes físicos ou químicos, quando comparados aos controles normais. Para determinar a sensibilidade de linfócitos de pacientes com FAP e também com pólipos adenomatosos esporádicos (AP) usou-se o radiomimético bleomicina (BLM). Foram estudados citogeneticamente 10 indivíduos com AP, 10 com FAP e 20 controles normais, pareados por sexo e idade. Indivíduos que apresentaram valores médios de quebras cromatídicas por célula superiores a 0,80 foram considerados sensíveis à droga. Observou-se uma diferença significativa entre pacientes com FAP e controles quanto às freqüências de quebras cromatídicas nos linfócitos tratados na fase G2. Entretanto, nenhuma diferença significativa foi observada entre pacientes com AP e controles quanto às freqüências de quebras cromatídicas nos linfócitos tratados. Nenhum indivíduo do grupo controle foi sensível à BLM e, entre os 20 pacientes, três mostraram suscetibilidade à droga. Não foi encontrada diferença significativa quanto a resposta à bleomicina entre indivíduos do sexo masculino e feminino. Entretanto, a distribuição de quebras induzidas por bleomicina em cada grupo cromossômico não foi similar nos pacientes do sexo feminino e controles normais. É possível que a sensibilidade cromossômica à BLM encontrada nos pacientes com FAP esteja relacionada a deficiência de reparo de DNA

Mola Completa em Gravidez Gemelar: relato de Caso

A gravidez gemelar na qual coexistem um feto normal e uma mola completa é um evento raro. Complicações clínicas e aumento de risco de malignização são de importância nesta patologia. Este trabalho descreve um caso de diagnóstico tardio em decorrência da presença do feto. Este diagnóstico foi feito no momento da resolução da gestação e confirmado por estudo histopatológico e citometria de fluxo. A resolução da gestação foi por via transpélvica em decorrência de hemorragia uterina maciça. O seguimento pós-molar evidenciou a persistência de níveis elevados de bhCG, obtendo-se remissão completa da doença com o uso do metotrexato. À luz deste caso, discutem-se o diagnóstico, a história natural e a conduta desta rara intercorrência na clínica obstétrica.Twin pregnancy in which a normal fetus and a complete mole develop at the same time is a rare event. Clinical complications and malignancy are frequent in this type of disease.This report is about a case of a late diagnosis due to the presence of the fetus. The diagnosis was made when the pregnancy was interrupted and then confirmed by histopathological study and flow cytometry. The pregnancy was terminated transpelvically due to massive uterine hemorrhage. The post-molar follow-up showed the persistence of high levels of bhCG. The patient's complete recovery was achieved after the administration of methotrexate. The diagnosis, natural history, and procedures for this rare disease are discussed in view of this case

Identification and complete sequencing of novel human transcripts through the use of mouse orthologs and testis cDNA sequences

The correct identification of all human genes, and their derived transcripts, has not yet been achieved, and it remains one of the major aims of the worldwide genomics community. Computational programs suggest the existence of 30,000 to 40,000 human genes. However, definitive gene identification can only be achieved by experimental approaches. We used two distinct methodologies, one based on the alignment of mouse orthologous sequences to the human genome, and another based on the construction of a high-quality human testis cDNA library, in an attempt to identify new human transcripts within the human genome sequence. We generated 47 complete human transcript sequences, comprising 27 unannotated and 20 annotated sequences. Eight of these transcripts are variants of previously known genes. These transcripts were characterized according to size, number of exons, and chromosomal localization, and a search for protein domains was undertaken based on their putative open reading frames. In silico expression analysis suggests that some of these transcripts are expressed at low levels and in a restricted set of tissues

A Transcript Finishing Initiative for Closing Gaps in the Human Transcriptome

We report the results of a transcript finishing initiative, undertaken for the purpose of identifying and characterizing novel human transcripts, in which RT-PCR was used to bridge gaps between paired EST clusters, mapped against the genomic sequence. Each pair of EST clusters selected for experimental validation was designated a transcript finishing unit (TFU). A total of 489 TFUs were selected for validation, and an overall efficiency of 43.1% was achieved. We generated a total of 59,975 bp of transcribed sequences organized into 432 exons, contributing to the definition of the structure of 211 human transcripts. The structure of several transcripts reported here was confirmed during the course of this project, through the generation of their corresponding full-length cDNA sequences. Nevertheless, for 21% of the validated TFUs, a full-length cDNA sequence is not yet available in public databases, and the structure of 69.2% of these TFUs was not correctly predicted by computer programs. The TF strategy provides a significant contribution to the definition of the complete catalog of human genes and transcripts, because it appears to be particularly useful for identification of low abundance transcripts expressed in a restricted set of tissues as well as for the delineation of gene boundaries and alternatively spliced isoforms

Identification of human chromosome 22 transcribed sequences with ORF expressed sequence tags

Transcribed sequences in the human genome can be identified with confidence only by alignment with sequences derived from cDNAs synthesized from naturally occurring mRNAs. We constructed a set of 250,000 cDNAs that represent partial expressed gene sequences and that are biased toward the central coding regions of the resulting transcripts. They are termed ORF expressed sequence tags (ORESTES). The 250,000 ORESTES were assembled into 81,429 contigs. Of these, 1,181 (1.45%) were found to match sequences in chromosome 22 with at least one ORESTES contig for 162 (65.6%) of the 247 known genes, for 67 (44.6%) of the 150 related genes, and for 45 of the 148 (30.4%) EST-predicted genes on this chromosome. Using a set of stringent criteria to validate our sequences, we identified a further 219 previously unannotated transcribed sequences on chromosome 22. Of these, 171 were in fact also defined by EST or full length cDNA sequences available in GenBank but not utilized in the initial annotation of the first human chromosome sequence. Thus despite representing less than 15% of all expressed human sequences in the public databases at the time of the present analysis, ORESTES sequences defined 48 transcribed sequences on chromosome 22 not defined by other sequences. All of the transcribed sequences defined by ORESTES coincided with DNA regions predicted as encoding exons by genscan. (http://genes.mit.edu/GENSCAN.html)