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A S Melo

Publications and source records attributed to A S Melo.

8 recordsLinked to original sources
PubMed2001

The contribution of 700,000 ORF sequence tags to the definition of the human transcriptome.

Open reading frame expressed sequences tags (ORESTES) differ from conventional ESTs by providing sequence data from the central protein coding portion of transcripts. We generated a total of 696,745 ORESTES sequences from 24 human tissues and used a subset of the data that correspond to a set of 15,095 full-length mRNAs as a means of assessing the efficiency of the strategy and its potential contribution to the definition of the human transcriptome. We estimate that ORESTES sampled over 80% of all highly and moderately expressed, and between 40% and 50% of rarely expressed, human genes. In our most thoroughly sequenced tissue, the breast, the 130,000 ORESTES generated are derived from transcripts from an estimated 70% of all genes expressed in that tissue, with an equally efficient representation of both highly and poorly expressed genes. In this respect, we find that the capacity of the ORESTES strategy both for gene discovery and shotgun transcript sequence generation significantly exceeds that of conventional ESTs. The distribution of ORESTES is such that many human transcripts are now represented by a scaffold of partial sequences distributed along the length of each gene product. The experimental joining of the scaffold components, by reverse transcription-PCR, represents a direct route to transcript finishing that may represent a useful alternative to full-length cDNA cloning.

Expressed Sequence Tags↗
PubMed2001

Differential predation of the planarian Dugesia tigrina on two mosquito species under laboratory conditions.

Two experiments were performed on the predation of the planarian Dugesia tigrina (Girard) upon 2 mosquito prey species, Aedes albopictus and Culex quinquefasciatus. Bioassays were carried out in sectioned tires with 2 liters of water. In the 1st experiment, predation was evaluated using 4, 8, and 12 mature planarians against 40 2nd-stage larvae of each mosquito species alone. In the 2nd experiment, the same 3 predator densities were used with a pool composed of 20 2nd-stage larvae of each mosquito species. In the 1st experiment, final corrected mortality of Ae. albopictus reached 89.1, 98.8, and 99.6% and final corrected mortality of Cx. quinquefasciatus reached 29.4, 48.0, and 53.0%, respectively, with 4, 8, and 12 planarians. In the 2nd experiment and when subjected to the density of 4 planarians, Ae. albopictus was more susceptible to predation, with a selectivity index of 0.87, whereas this index was 0.13 for Cx. quinquefasciatus. Predation was more intensive during the 1st 4 days of the experiments, when most larvae were in the 2nd and 3rd stages. We observed that Cx. quinquefasciatus larvae were faster than Ae. albopictus in reacting to planarian contacts, resulting in more success in escaping from the predator attacks.

Aedes↗
PubMed2000

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).

Chromosomes, Human, Pair 22↗
PubMed1999

Divided left atrium associated with supravalvar mitral ring.

Reported is a case with a rare association of divided left atrium, supramitral stenosing ring of the left atrium, connection of the left superior caval vein to the roof of the left atrium, unroofed coronary sinus with an interatrial communication at the mouth of the unroofed sinus and ventricular septal defect. The need for a complete echocardiographic examination in the presence of pulmonary venous obstruction is emphasized. Surgery was successful in spite of significant preoperative pulmonary hypertension.

Cor Triatriatum↗
PubMed1998

Evolutionary distances and identification of Candida species in clinical isolates by randomly amplified polymorphic DNA (RAPD).

Fast and reliable identification of different species of the genus Candida is important to define adequate therapeutic decisions, because the different species have highly variable susceptibilities to antifungal drugs; azoles and amphothericin B. Accurate statistical records on case history and epidemiological studies also depend on effective identification. To address this problem we established a RAPD method that enabled direct identification of five very common species of Candida. Initially, reference band patterns were established for C. albicans, C. tropicalis, C. parapsilosis, C. glabrata and C. krusei. One of the primers, M2, showed remarkably conserved intra-specific patterns of approximately 10 bands each, ranging in size from 2.0 to 0.1 kb. These patterns were significantly different and species-specific. Few bands were conserved between different species of Candida, which was assumed to be consistent with their phylogenetic relatedness. In addition, band patterns were constant and reproducible and DNA isolated from single colonies yielded sufficient DNA for identification. The reference band patterns were then used, in blind experiments, to identify species of Candida in 50 randomly chosen samples, including clinical isolates and ATCC strains. RAPD results were 100% consistent with results obtained by conventional diagnostic methods and were achieved in one day instead of several days taken by conventional methods. Because ideal identification methods should be consistent with phylogeny and taxonomy we tested whether RAPD could be used to calculate genetic distances. Comparison of RAPD phylogenetic trees with 18S rRNA trees showed significant differences in tree topologies which indicated that RAPD data could not accurately measure the relative distances between different species. Also, computer simulations of RAPD random patterns were used to test whether the observed degree of RAPD band pattern similarities could occur at random. These simulations suggested that the level of inter-specific band pattern similarities observed in our data could be obtained at random, while intraspecific pattern similarities could not. RAPD would be helpful to discriminate between isolates but not to quantitate the differences. We suggest that the inaccurate estimate of genetic distances from RAPD is a general limitation of the technique and not a specific problem of our identification method. Because of the repetitive character of the target sequences, genetic distances calculated from RAPD could be affected by paralogy, namely, recombination and duplication events not parallel with speciation events.

Candida↗
PubMed1993

Transposition of the great arteries: correction with conversion from single to dual coronary artery system.

We describe the case of a newborn child with D-transposition of the great arteries who was found to have an uncommon single-origin coronary artery system. Surgical correction by arterial switch was performed but resulted in tension of the left coronary branch, which prevented discontinuation of cardiopulmonary bypass. The problem was eventually resolved by conversion into a dual coronary artery system through direct implantation of the left coronary branch into the aorta. The patient remains well, free from ischemia and with a patent left coronary artery, 2 years after operation.

Cardiopulmonary Bypass↗
PubMed1991

Preservation of the pulmonary annulus in total correction of tetralogy of Fallot. Decreasing transannular gradients in the early follow-up period.

The integrity of the pulmonary annulus was preserved in 21 of 22 children consecutively subjected to total correction of tetralogy of Fallot. There was one early death (4.8%). The 20 survivors were studied prospectively and constitute the basis of this report. Mean age was 59.3 +/- 35.3 months (range 6 months-12 years). Eight patients (40%) had previous Blalock-Taussig shunts and 3 (15%) had associated cardiac anomalies. Two-dimensional Doppler echocardiography had demonstrated right ventricle to main pulmonary artery peak systolic gradients of 75.4 +/- 12.7 mmHg (range 50-104 mmHg). Ventricular infundibulectomy was carried out in all patients but one, who had abnormal coronary anatomy. Extensive incision or resection of hypertrophied or abnormal muscle bands was performed. Pulmonary valve commissurotomy was performed in 14 patients (70%), 10 (50%) had autologous pericardium supravalvular enlargement of the pulmonary trunk and one (5%) had an infundibular bovine pericardial patch. Intraoperative, postrepair right/left ventricular pressure ratios were 0.67 +/- 0.18 (range 0.41-1.0). All ratios were accepted, because all patients were haemodynamically well and only two required inotropic (dopamine) support. There was no late mortality. During the early follow-up period (mean 13.0 +/- 5.4 months, range 7-25 months), all patients had two-dimensional Doppler echocardiography measured gradients at discharge (mean 44.2 +/- 22.6 mmHg, range 10-86 mmHg; p less than 0.001 vs. preoperative values), at 3 months (mean 31.1 +/- 14.5 mmHg, range 8-64 mmHg; p less than 0.011 vs. values at discharge) and at 6 months (mean 28.5 +/- 14.3 mmHg, range 12-57 mmHg; p = 0.009 vs. values at discharge). A similar favourable evolution of the diameters of the pulmonary annulus and of the right pulmonary artery was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Biophysical Phenomena↗