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Biomedical subjects

J C Tohá

Publications and source records attributed to J C Tohá.

18 recordsLinked to original sources
PubMed1993

Algorithm for assisting medical diagnosis.

An algorithm for medical diagnosis assistance is described. In this algorithm, the patient is identified following the simultaneous evaluation of its degree of similarity with a given disease, as well as the extent of disagreement with the rest of diseases considered in the differential diagnosis. In an example the algorithm is applied to the diagnosis assistance of some neuropathies.

Algorithms↗
PubMed1990

Pattern recognition of the secondary structure of proteins (alpha-helix and beta-structure).

In this paper, an algorithm for the pattern recognition of secondary structure of proteins is proposed. The procedure simultaneously evaluates the contribution of all the residues of a given peptide to its conformation. By means of the algorithm it is possible to select from a universe of well known proteins the most representative alpha-helix and beta-structure peptides, and to use these peptides, as screening matrices to define the unknown structure of any peptide.

Algorithms↗
PubMed1989

Codon evolution and conservation of the reading phase in genetic code translation.

The description of the optimized evolution of a code based on 4 nucleotides involves a sequential transition of codons, formed firstly by monomers evolving to dimers and then to triplets, in accordance with the progressive increase of the number of amino acids to be coded. The successive increase in the size of these codons during evolution implies changes in the phase reading of the genetic message, which could become chaotic. In order to overcome this constraint, this paper proposes a codon evolution where two things occur simultaneously: codons change in size and there is an alternation of the molecule which holds the information. For example, the nucleotides of the original oligonucleotide are read as monomers when they are translated to an oligopeptide, but further on, this oligopeptide which is read as amino acid dimers, is translated to a nucleotide form (oligonucleotide). Finally, amino acids conforming a peptide are translated from this oligonucleotide, through a reading of triplets. Although plausible, this evolution is a low-probability process due to the fact that it requires a singular sequence of the oligonucleotide and oligopeptide involved. An alternative hypothesis of evolution is also discussed. It proposes that with the exclusion of the establishment of monomer and dimer codons, there is a direct generation of a code of trinucleotides which arises only when a certain number of amino acids has already been generated. Both hypotheses are discussed in terms of the development of a code in which an optimized hardware is maintained through out its evolution.

Amino Acids↗
PubMed1987

A general algorithm for assisting medical diagnosis.

An algorithm for assisting medical diagnosis is designed; this algorithm is highly reliable and can be given general use. The method is based on the comparison of the column vector of the symptoms of a given patient with each of the columns of disease symptoms which appear on a matrix. On this matrix, the symptoms have been arranged according to the hierarchic order of each of the symptoms, which facilitates the creation of a file. Moreover, this system undertakes a simultaneous comparison of all the diseases considered in the differential diagnosis, in comparison to the alternate procedures in which the patient's symptoms are compared in separate succession with each of the vectors of the disease under study.

Algorithms↗
PubMed1986

A simple algorithm for assisting medical diagnosis.

This is a description of an algorithm to assist in the selection of the most probable diagnosis of a given patient. This algorithm is based on the comparison of a scaled column vector of the symptoms displayed by the patient, and of each column of symptoms appearing in a disease matrix. Moreover, the same algorithm gives the degree of similarity of the diseases compared by the differential diagnosis, as well as the hierarchic order of the symptoms that characterise any disease.

Algorithms↗