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Biomedical subjects

M A Andrade

Publications and source records attributed to M A Andrade.

44 records · Page 3Linked to original sources
PubMed1994

Incidence of different forms of thyroid dysfunction and its degrees in an iodine sufficient area.

STUDY OBJECTIVE: The aim of the study was to determine the incidence of thyroid dysfunction in an iodine sufficient area (Vigo city, Galicia, North-West of Spain). DESIGN: Case-finding study during a 3-year (1990-1992) period. SUBJECTS: Subjects from a random sample of the population with abnormal results on FT4, sensitive-TSH or antithyroid autoantibodies. MEASUREMENTS: Thyroid size by ultrasound study. FT4 by RIA; TSA Ab by radio receptor assays; TSH, Tg Ab and TMS Ab by IRMA. MAJOR RESULTS: Overall incidence of thyroid dysfunction was 97.96 per 100,000 per year (CI 95% 78.86-117.06); female 162.45, male 17.44. Incidence rate of hyperthyroidism was 52.37 per 100,000 per year (CI 95% 38.41-66.36); 24.24 for Graves' disease, 11.63 for nodular hyperthyroidism, 13.57 for iatrogenic hyperthyroidism and 2.90 for others causes. Incidence rate of hypothyroidism was 45.58 per 100,000 per year (CI 95% 32.55-58.620 27.15 for hypothyroid autoimmune thyroiditis, 8.72 for postoperative hypothyroidism, 4.89 for miscellaneous hypothyroidism, 1.93 for amiodarone induced hypothyroidism and 2.90 for secondary hypothyroidism. CONCLUSIONS: This investigation provides extensive data on incidence of clinical and subclinical thyroid dysfunction and its different forms in an iodine sufficient area.

Adult↗
PubMed1993

Evaluation of secondary structure of proteins from UV circular dichroism spectra using an unsupervised learning neural network.

An optimized self-organizing map algorithm has been used to obtain protein topological (proteinotopic) maps. A neural network is able to arrange a set of proteins depending on their ultraviolet circular dichroism spectra in a completely unsupervised learning process. Analysis of the proteinotopic map reveals that the network extracts the main secondary structure features even with the small number of examples used. Some methods to use the proteinotopic map for protein secondary structure prediction are tested showing a good performance in the 200-240 nm wavelength range that is likely to increase as new protein structures are known.

Algorithms↗
PubMed1991

Study of an error-prone hypercycle formed from two kinetically distinguishable species.

Asymmetry within both the amplification factor values (Ak) and cross-catalytic hypercyclic constant (Kjk) and its influence on the stability of a two-membered error-prone hypercycle has been exhaustively studied from a deterministic point of view and the bifurcation diagram as a function of the quality factor (Q) has been obtained. In the more general case, several Q critical values appear, changing their relative position in the diagram depending on the Ak and Kjk values. The order of the Q critical values affects both the general properties of the system and the stability of the hypercyclic organization. The importance of this asymmetry in the selective and evolutionary properties of the hypercycle is also discussed.

Journal Article↗
PubMed1991

Early experience with crimped bovine pericardial conduit for arterial reconstruction.

A bovine pericardial conduit was developed in the laboratory incorporating the principle of crimping used for synthetic vascular prostheses. The pericardium was processed in glutaraldehyde and the tube was crimped by a technique which preserves the integrity of collagen fibres. This vascular substitute presents a non-thrombogenic and non-porous inner surface which does not require preclotting and does not leak. The material is very soft, easy to handle and suture, coapts nicely to suture lines resulting in a hemostatic anastomosis. The crimping design provides longitudinal elasticity and resistance to collapsing, retains its shape with bending and avoids kinking. Crimping provides a circular tube which makes the construction of the anastomosis easier. Experimental studies in dogs demonstrated absence of thromboembolism with the conduit implanted in the abdominal aorta. Fibrin accumulation was not noted in the convexities of the crimps. This conduit was designed for aortic and pulmonary reconstruction and available in different sizes with or without a biological valve. Initial clinical experience included its use in 10 patients with aortic dissections or aortic aneurysms from August 1989 to March 1990. A reconstruction of the abdominal aorta was performed in 2 patients, the descending thoracic aorta in 2, the ascending aorta in 2 and the ascending aorta including the aortic valve and reimplantation of coronary arteries in 4. For the latter 4, composite crimped pericardial tubes containing a porcine bioprosthesis were used. An additional patient with a single ventricle underwent a Fontan type operation also employing a valved crimped pericardial conduit.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Protein repeats: structures, functions, and evolution.

Internal repetition within proteins has been a successful strategem on multiple separate occasions throughout evolution. Such protein repeats possess regular secondary structures and form multirepeat assemblies in three dimensions of diverse sizes and functions. In general, however, internal repetition affords a protein enhanced evolutionary prospects due to an enlargement of its available binding surface area. Constraints on sequence conservation appear to be relatively lax, due to binding functions ensuing from multiple, rather than, single repeats. Considerable sequence divergence as well as the short lengths of sequence repeats mean that repeat detection can be a particularly arduous task. We also consider the conundrum of how multiple repeats, which show strong structural and functional interdependencies, ever evolved from a single repeat ancestor. In this review, we illustrate each of these points by referring to six prolific repeat types (repeats in beta-propellers and beta-trefoils and tetratricopeptide, ankyrin, armadillo/HEAT, and leucine-rich repeats) and in other less-prolific but nonetheless interesting repeats.

Amino Acid Motifs↗
PubMedDate not supplied

[Postoperative acute kidney failure: comparative study in abdominal surgery].

Five hundred and eighty-two patients were examined in a retrospective study to identify the incidence of postoperative acute renal failure (ARF) in obstructive jaundice. The patients were treated at the "Hospital das Clínicas da UFMG" during a 10 year period (1977-1987), and were operated on for gastric carcinoma, portal hypertension, peritonitis, and obstructive jaundice. The incidence of ARF was 4.9% (29 patients), and increased in patients with peritonitis and obstructive jaundice (p less than 0.0001) and decreased in the patients with gastric carcinoma. Infection was significant when associated to ARF in patients with portal hypertension and peritonitis, but not significant in patients with gastric carcinoma and obstructive jaundice (p less than 0.001). These results show the importance of postoperative ARF in obstructive jaundice.

Acute Kidney Injury↗