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S Hazout

Publications and source records attributed to S Hazout.

14 recordsLinked to original sources
PubMed1992

Searching for geometric molecular shape complementarity using bidimensional surface profiles.

The study presented herein is a bidimensional approach to the complementarity of two molecular surfaces. From two chosen sections we have established a methodology of generating the optimal matching of two shapes. Our approach consists in describing two molecular surface sections by a shape vector (the angular profile), in finding their matching patterns by comparison of the two profiles, and in optimizing the relative locations of the two sections in two-dimensional space, using rotations and translations defined by geometric characteristics. The set of optimal configurations are successively displayed on a screen. Satisfying results have been obtained for the matching of the complex kallikreine A-trypsin pancreatic bovin 2. This efficient method could be used as a preprocessing for a tridimensional shape complementarity approach between two molecular surfaces.

Animals↗
PubMed1992

A method for delineating structurally homogeneous regions in protein sequences.

A homogeneous region in a protein sequence is a set of contiguous residues that share common features, concerning physico-chemical, structural and mutational information. This paper presents a method for identifying such homogeneous regions. From a profile describing a given type of biological information along the sequence, the algorithm allows the segmentation of the sequence by optimizing a criterion characterized by two user-defined control parameters: the 'homogenizing degree' of the regions and the 'site neighbourhood' size. We apply the method to the envelope proteins of the human immunodeficiency virus HIV-1, for the identification of homogeneous regions in a hydrophobicity profile and the delineation of variable and conserved regions in a variability profile.

Algorithms↗
PubMed1992

[Familial Alzheimer's disease in France: results of a preliminary survey].

This study concerns French families with Alzheimer's disease (13 families, with 37 diseased individuals). The incidence of female patients is higher than that of males. Variance of the age of onset is less important for intra-familial than inter-familial cases. The mean duration of the disease is shorter for early onset forms. One of these families was retained for molecular genetics studies.

Age Factors↗
PubMed1991

FORME: an interactive package for protein backbone deformation.

The FORME package presented herein is designed for modeling purposes: It allows interactive deformation of the protein backbone. General formalism on transformations is introduced and the operators of stretching inside an "acceptance area" and stretching with end-block invariance (i.e., governed by a translational moving) are described. A discussion is presented on the choice of strategy to achieve an interactive deformation tool. Perspectives about complex transformations are presented.

Computer Graphics↗
PubMed1991

A new approach to the rapid determination of protein side chain conformations.

Two efficient algorithms have been developed which allow amino acid side chain conformations to be optimized rapidly for a given peptide backbone conformation. Both these approaches are based on the assumption that each side chain can be represented by a small number of rotameric states. These states have been obtained by a dynamic cluster analysis of a large data base of known crystallographic structures. Successful applications of these algorithms to the prediction of known protein conformations are presented.

Algorithms↗
PubMed1991

MASH: an interactive program for multiple alignment and consensus sequence construction for biological sequences.

This paper presents a method for the multiple alignment of a sequence set. The MASH algorithm uses a non-redundant database of common motifs and an 'alignment priority' criterion that depends on the length and the occurrence frequency of the patterns in the set of sequences. This user-defined criterion allows the determination of the series of the patterns to be aligned. This program is applied to a fragment of envelope gene env gp120 for 20 isolates of the immunodeficiency virus. The multiplicity of alignments obtained by modifying the criterion parameters reveals different aspects of similarity between the sequences.

Algorithms↗
PubMed1991

'Size leap' algorithm: an efficient extraction of the longest common motifs from a molecular sequence set. Application to the DNA sequence reconstruction.

We propose a new method, called 'size leap' algorithm, of search for motifs of maximum size and common to two fragments at least. It allows the creation of a reduced database of motifs from a set of sequences whose size obeys the series of Fibonacci numbers. The convenience lies in the efficiency of the motif extraction. It can be applied in the establishment of overlap regions for DNA sequence reconstruction and multiple alignment of biological sequences. The method of complete DNA sequence reconstruction by extraction of the longest motifs ('anchor motifs') is presented as an application of the size leap algorithm. The details of a reconstruction from three sequenced fragments are given as an example.

Algorithms↗
PubMed1991

Genetic similarity maps and immunoglobulin allotypes of eleven populations from the Pyrenees (France).

The genetic heterogeneity of eleven populations from the Pyrenees (France) based on the polymorphism of the immunoglobulin allotypes is studied by means of a 'genetic similarity map'. The method described here, called 'Mobile Node Method', allows the deformation of a square grid, in which the studied region is represented, by moving the nodes at each step in order to reduce the difference between the geographic and genetic distances. This tool allows the overall quantification of the genetic heterogeneity of a population set and possibly the study of its dynamics. Other maps constructed to complete the interpretation are 'map of moving vectors', 'iso-displacement curves' and 'site displacements'. This study identified an overall genetic homogeneity among the Pyrenean populations and several local genetic heterogeneities in different regions.

France↗
PubMed1991

The p49/TaqI Y-specific DNA haplotypes in Australian aborigines.

The TaqI/p49 Y-specific RFLPs were studied in 59 Australian aborigines. A new haplotype was found (not present in Caucasians and Africans, number XXV). In the revised genealogy of haplotypes, Australian haplotypes appear to occupy an intermediate position between African Pygmies and Papua haplotypic repartitions, while the most common Australian haplotypes (haplotype III, 25% of the subjects) is apparently derived from them.

Australia↗
PubMed1990

The p49/TaqI Y-specific polymorphisms in three groups of Indians.

The TaqI/p49 Y-specific RFLPs were studied in 98 Indians coming from 3 locations in the country. A new allele (G0) and five new haplotypes (XX-XXIV) were found, not present in Caucasians and in Africans. In the genealogy of haplotypes, the new Indian haplotypes appear grouped together, and all Indian haplotypes occupy an intermediate position between Caucasian and African haplotypes.

Alleles↗
PubMed1979

Computer-aided analysis of chromosomal aberrations occurring in an abnormal human karyotype.

A semi-automatic method for recognition of chromosomal changes is presented: from a coded description of an abnormal chromosome (formulated with the aid of an R-banding technique), a computer program makes simulations to reconstitute this chromosomal image from a group of normal chromosomes. Nine types of aberrations (see text) can thus be recognized and the aggregate structure of a group of abnormal chromosomes occurring in a human karyotype can also be rediscovered.

Chromosome Aberrations↗
PubMed1978

The thymol turbidity test and determination of serum cholesterol : two tests to abandon in the routine evaluation of liver function.

The thymol turbidity test (Macglan's test) and the determination of serum cholesterol are still performed routinely as liver function tests in many laboratories. In this report, we have employed quantitative methods in order to evaluate the real usefulness of these two parameters. In a first step, the value of the thymol test and of cholesterol determination for the discrimination of the 13 most frequent hepato-biliary diseases was studied by analysis of variance, and compared to that of the following tests : serum bilirubin, serum glutamic pyruvic transaminase, serum alkaline phosphatase serum protein electrophoresis and prothrombin time. It was found that of all these parameters, the thymol test and cholesterol measurement had the lowest discriminatory powers. In a second step, the consequences of the suppression of the two tests were examined by linear discrimination analysis, which was done for all the possible pairs of diseases. It appeared that in each case, the loss of information due to the elimination of the thymol test or of cholesterol determination was nil or negligible. We conclude therefore that the thymol turbidity test and determination of serum cholesterol should be abandoned as routine tests of liver function.

Cholesterol↗
PubMed1977

Planning the suicide experiments.

Suicide experiments involve a great degree of uncertainty in the counting of cell colonies. This work studies from a statistical point of view the precision of the estimation as a function of the number of experimental units which are used. Assuming that the colony numbers in recipients follow a Poisson distribution, we give the necessary number of recipients (a) to determine with a given accuracy the percentage of DNA synthesizing cells (S cells), (b) to test whether or not a cell population is quiescent, and (c) to compare the percentages of S cells in two cell populations.

Animals↗