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C Saraiva

Publications and source records attributed to C Saraiva.

8 recordsLinked to original sources
PubMed2000

Molecular methods for the detection of mutations.

We report the results of a collaborative study aimed at developing reliable, direct assays for mutation in human cells. The project used common lymphoblastoid cell lines, both with and without mutagen treatment, as a shared resource to validate the development of new molecular methods for the detection of low-level mutations in the presence of a large excess of normal alleles. As the "gold standard, " hprt mutation frequencies were also measured on the same samples. The methods under development included i) the restriction site mutation (RSM) assay, in which mutations lead to the destruction of a restriction site; ii) minisatellite length-change mutation, in which mutations lead to alleles containing new numbers of tandem repeat units; iii) loss of heterozygosity for HLA epitopes, in which antibodies can be used to direct selection for mutant cells; iv) multiple fluorescence-based long linker arm nucleotides assay (mf-LLA) technology, for the detection of substitutional mutations; v) detection of alterations in the TP53 locus using a (CA) array as the target for the screening; and vi) PCR analysis of lymphocytes for the presence of the BCL2 t(14:18) translocation. The relative merits of these molecular methods are discussed, and a comparison made with more "traditional" methods.

Base Sequence↗
PubMed1999

Association of p53 genomic instability with the glutathione S-transferase null genotype in gastric cancer in the Portuguese population.

AIMS: p53 gene mutations are the most common genetic changes known to occur in human cancer. In previous studies, the presence of alterations to the p53 gene has been linked to the null phenotype of the glutathione S-transferase mu gene (GSTM1). GSTM1 appears to be part of a protective mechanism against the development of cancers in which environmental chemical carcinogens are involved. To screen for such an association in stomach cancer, p53 allelic loss and genomic instability and GSTM1 genotypes were investigated in gastric tumour DNA samples from 113 patients. METHODS: The polymerase chain (PCR) reaction was used to amplify a (CA) repeat array in the p53 locus; electrophoresis, genotyping, and allele quantification were performed using an automated DNA sequencer and Genescan software. The presence of the GSTM1 gene was determined by means of a differential PCR in which multiple genes were co-amplified in the same reaction tube. RESULTS: Loss of heterozygosity (LOH) of the p53 gene was found in 36 of 87 informative cases and genomic instability was present in eight of 113 cases. Further analysis into histological subtypes and sites of tumours did not show any positive association with p53 loss. An association between the presence of LOH and the GSTM1 null genotype was not seen; however, all the samples with genomic instability of the p53 gene (eight of 113) also showed a GSTM1 null genotype. CONCLUSION: This study does not support the hypothesis of an association between LOH in the p53 gene and the GSTM1 null genotype, but suggests that the GSTM1 null genotype might influence p53 genomic instability.

Alleles↗
PubMed1990

Hepatic abscess in Crohn's disease.

Hepatic abscess is a rare complication of Crohn's disease. The present report describes an additional case diagnosed by CT scanning and successfully treated by surgery. Recognition of this complication is important because early therapy could improve the prognosis.

Adult↗
PubMedDate not supplied

[Auto-immune polyglandular syndrome in an adult with chronic active hepatitis].

We present a case report with IgA deficiency, pernicious anemia, chronic active hepatitis, insulino-dependent diabetes mellitus and hypogonadism. A diagnosis of Polyglandular Auto-immune Syndrome was done and we discuss the difficulty in including this particular case in any of the types of the Neufeld's classification of Polyglandular Auto-immune Disease.

Adult↗
PubMedDate not supplied

[Pneumopyopericardium].

Pneumopyopericardium is a rare disease. The most common causes seems to be ulceration or carcinoma in the lower esophagus or upper stomach. We report a case of pneumopiopericardium secondary to a pneumonia in a 60 years-old-woman after the first course of chemotherapy for acute myeloid leukemia. We use this case as a basis for a review of the literature on similar cases. This syndrome can be recognised promptly because of its characteristic physical findings and radiographic features.

Female↗