Ricardo Ferreira - Academia.edu (original) (raw)

Uploads

Papers by Ricardo Ferreira

Research paper thumbnail of Evidence for CTLA4 as a susceptibility gene for systemic lupus erythematosus

European Journal of Human Genetics, 2004

Several lines of evidence implicate the Cytotoxic T Lymphocyte Antigen 4 (CTLA4) gene in suscepti... more Several lines of evidence implicate the Cytotoxic T Lymphocyte Antigen 4 (CTLA4) gene in susceptibility to autoimmune disease. We have examined the association of systemic lupus erythematosus (SLE) with polymorhisms within the CTLA4 gene that were previously proposed to regulate CTLA-4 function: a single nucleotide polymorphism (SNP) in position þ 49 of exon 1 and a dinucleotide repeat in the 3 0 untranslated region (3'UTR). The 3 0 UTR repeat showed a significant association with SLE, with one allele conferring susceptibility and another conferring protection to the disease. The associated alleles do not support previous suggestions of an allele size-dependent effect of the 3' UTR polymorphism in autoimmunity development and instead suggest that it is in linkage disequilibrium with a true causative locus. No association of the exon 1 SNP with SLE was found in our population. Given the conflicting results obtained in different studies on the association of SLE with this polymorphism, we performed a meta-analysis including seven previously published studies and the present one. Significantly increased and decreased risks for SLE were found for carriers of the G allele and the A allele, respectively. The functional characterization of disease-associated CTLA4 gene variants is now required to elucidate their role in the pathogenesis of SLE and other autoimmune diseases.

Research paper thumbnail of Patterns of Gene Duplication in Saccharomyces cerevisiae and Caenorhabditis elegans

Journal of Molecular Evolution, 2003

In this paper we present a new method for detecting block duplications in a genome. It is more st... more In this paper we present a new method for detecting block duplications in a genome. It is more stringent than previous ones in that it requires a more rigorous definition of paralogous genes and that it requires the paralogous proteins on the two blocks to be contiguous. In addition, it provides three criterion choices: (1) the same composition (i.e., having the same paralogues in the two windows), (2) the same composition and gene order, and (3) the same composition, gene order, and gene orientation. The method is completely automated, requiring no visual inspection as in previous methods. We applied it to analyze the complete genomes of S. cerevisiae and C. elegans. In yeast we detected fewer duplicated blocks than previously reported. In C. elegans, however, we detected more block duplications than previously reported, indicating that although our method has a more stringent definition of block duplication than previous ones, it may be more sensitive in detection because it considers every possible window rather than only fixed nonoverlapping windows. Our results show that block duplication is a common phenomenon in both organisms. The patterns of block duplication in the two species are, however, markedly different. The yeast shows much more extensive block duplication than the nematode, with some chromosomes having more than 40% of the duplications derived from block duplications. Moreover, in the yeast the majority of block duplications occurred between chromosomes, while in the nematode most block duplications occurred within chromosomes.

Research paper thumbnail of Clinical Experience with Dynamic Cardiomyoplasty

Journal of Cardiac Surgery, 1990

Abstract Dynamic cardiomyoplasty using the latissimus dorsi muscle graft (LDMG) was applied to 11... more Abstract Dynamic cardiomyoplasty using the latissimus dorsi muscle graft (LDMG) was applied to 11 patients with dilated cardiomyopathy of different etiologies. Our first case was operated on July 1987. All patients were in Functional Class (FC) IV New York Heart Association (NYHA) and had multiple previous admissions in intensive care units for intractable cardiac insufficiency. Two patients died during the procedure, the perioperative mortality was 18%. One patient died of recurrent acute myocarditis at the fourth postoperative month and a second patient died in the sixteenth postoperative month. Both patients were asymptomatic, in FC Ml, and the cause of death was sudden arrhythmia (ventricular fibrillation). The remaining seven patients (63.6%) were in FC I-II and the longest follow-up was 30 months. In all patients, the ejection fraction (EF) by radioisotopic ventriculography improved an average of 50% as well as their ergometric test. Dynamic cardiomyoplasty appears to be a satisfactory alternative for the treatment of patients with severe cardiac insufficiency secondary to dilated cardiomyopathy. Its main advantage seems to be a significant improvement in the quality of life for these patients.

Research paper thumbnail of Reduction of reperfusion injury with mannitol cardioplegia

Annals of Thoracic Surgery, 1989

Forty consecutive patients undergoing myocardial revascularization were divided into two equal gr... more Forty consecutive patients undergoing myocardial revascularization were divided into two equal groups: group 1 received standard cardioplegic solution, and group 2 received a solution containing mannitol, 59.8 mmol/L. In 6 patients in each group, myocardial biopsies were done before ischemia and at the time of reperfusion. Samples were assessed by chemiluminescence to determine oxidative stress and by electron microscopic studies. A significant reduction in atrial arrhythmias was observed in the mannitol group. Chemiluminescence in group 1 showed a photoemission of 37.6 f 3.5 cpm/mg of protein x for the preischemia samples and 74.8 f 16 c p d m g of protein x for the reperfusion samples ( p < 0.001). In group 2, the values for chemiluminescence were 37.7 f 3.4 c p d m g of protein x lo-' and 40 f 6.1 lthough topical cooling and cold potassium car-A dioplegia have markedly reduced mortality and

Research paper thumbnail of Assessment of myocardial oxidative stress in patients after myocardial revascularization

American Heart Journal, 1988

Research paper thumbnail of Metadata Driven Aspect Specification

ABSTRACT Metadata provides the background information that describes the content, quality, struct... more ABSTRACT Metadata provides the background information that describes the content, quality, structure and other appropriate data characteristics. The current work proposes the use of metadata for the structural specification of crosscutting concerns in the early stages ...

Research paper thumbnail of Evidence for CTLA4 as a susceptibility gene for systemic lupus erythematosus

European Journal of Human Genetics, 2004

Several lines of evidence implicate the Cytotoxic T Lymphocyte Antigen 4 (CTLA4) gene in suscepti... more Several lines of evidence implicate the Cytotoxic T Lymphocyte Antigen 4 (CTLA4) gene in susceptibility to autoimmune disease. We have examined the association of systemic lupus erythematosus (SLE) with polymorhisms within the CTLA4 gene that were previously proposed to regulate CTLA-4 function: a single nucleotide polymorphism (SNP) in position þ 49 of exon 1 and a dinucleotide repeat in the 3 0 untranslated region (3'UTR). The 3 0 UTR repeat showed a significant association with SLE, with one allele conferring susceptibility and another conferring protection to the disease. The associated alleles do not support previous suggestions of an allele size-dependent effect of the 3' UTR polymorphism in autoimmunity development and instead suggest that it is in linkage disequilibrium with a true causative locus. No association of the exon 1 SNP with SLE was found in our population. Given the conflicting results obtained in different studies on the association of SLE with this polymorphism, we performed a meta-analysis including seven previously published studies and the present one. Significantly increased and decreased risks for SLE were found for carriers of the G allele and the A allele, respectively. The functional characterization of disease-associated CTLA4 gene variants is now required to elucidate their role in the pathogenesis of SLE and other autoimmune diseases.

Research paper thumbnail of Patterns of Gene Duplication in Saccharomyces cerevisiae and Caenorhabditis elegans

Journal of Molecular Evolution, 2003

In this paper we present a new method for detecting block duplications in a genome. It is more st... more In this paper we present a new method for detecting block duplications in a genome. It is more stringent than previous ones in that it requires a more rigorous definition of paralogous genes and that it requires the paralogous proteins on the two blocks to be contiguous. In addition, it provides three criterion choices: (1) the same composition (i.e., having the same paralogues in the two windows), (2) the same composition and gene order, and (3) the same composition, gene order, and gene orientation. The method is completely automated, requiring no visual inspection as in previous methods. We applied it to analyze the complete genomes of S. cerevisiae and C. elegans. In yeast we detected fewer duplicated blocks than previously reported. In C. elegans, however, we detected more block duplications than previously reported, indicating that although our method has a more stringent definition of block duplication than previous ones, it may be more sensitive in detection because it considers every possible window rather than only fixed nonoverlapping windows. Our results show that block duplication is a common phenomenon in both organisms. The patterns of block duplication in the two species are, however, markedly different. The yeast shows much more extensive block duplication than the nematode, with some chromosomes having more than 40% of the duplications derived from block duplications. Moreover, in the yeast the majority of block duplications occurred between chromosomes, while in the nematode most block duplications occurred within chromosomes.

Research paper thumbnail of Clinical Experience with Dynamic Cardiomyoplasty

Journal of Cardiac Surgery, 1990

Abstract Dynamic cardiomyoplasty using the latissimus dorsi muscle graft (LDMG) was applied to 11... more Abstract Dynamic cardiomyoplasty using the latissimus dorsi muscle graft (LDMG) was applied to 11 patients with dilated cardiomyopathy of different etiologies. Our first case was operated on July 1987. All patients were in Functional Class (FC) IV New York Heart Association (NYHA) and had multiple previous admissions in intensive care units for intractable cardiac insufficiency. Two patients died during the procedure, the perioperative mortality was 18%. One patient died of recurrent acute myocarditis at the fourth postoperative month and a second patient died in the sixteenth postoperative month. Both patients were asymptomatic, in FC Ml, and the cause of death was sudden arrhythmia (ventricular fibrillation). The remaining seven patients (63.6%) were in FC I-II and the longest follow-up was 30 months. In all patients, the ejection fraction (EF) by radioisotopic ventriculography improved an average of 50% as well as their ergometric test. Dynamic cardiomyoplasty appears to be a satisfactory alternative for the treatment of patients with severe cardiac insufficiency secondary to dilated cardiomyopathy. Its main advantage seems to be a significant improvement in the quality of life for these patients.

Research paper thumbnail of Reduction of reperfusion injury with mannitol cardioplegia

Annals of Thoracic Surgery, 1989

Forty consecutive patients undergoing myocardial revascularization were divided into two equal gr... more Forty consecutive patients undergoing myocardial revascularization were divided into two equal groups: group 1 received standard cardioplegic solution, and group 2 received a solution containing mannitol, 59.8 mmol/L. In 6 patients in each group, myocardial biopsies were done before ischemia and at the time of reperfusion. Samples were assessed by chemiluminescence to determine oxidative stress and by electron microscopic studies. A significant reduction in atrial arrhythmias was observed in the mannitol group. Chemiluminescence in group 1 showed a photoemission of 37.6 f 3.5 cpm/mg of protein x for the preischemia samples and 74.8 f 16 c p d m g of protein x for the reperfusion samples ( p < 0.001). In group 2, the values for chemiluminescence were 37.7 f 3.4 c p d m g of protein x lo-' and 40 f 6.1 lthough topical cooling and cold potassium car-A dioplegia have markedly reduced mortality and

Research paper thumbnail of Assessment of myocardial oxidative stress in patients after myocardial revascularization

American Heart Journal, 1988

Research paper thumbnail of Metadata Driven Aspect Specification

ABSTRACT Metadata provides the background information that describes the content, quality, struct... more ABSTRACT Metadata provides the background information that describes the content, quality, structure and other appropriate data characteristics. The current work proposes the use of metadata for the structural specification of crosscutting concerns in the early stages ...