Biomedical subjects

C Chappey

Publications and source records attributed to C Chappey.

7 recordsLinked to original sources

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↗

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↗

PubMed1990

[Blepharoplasty: various technics in surgery of eyelid aging].

The authors reviewing their own experience of blepharoplasty (92 cases) over the last ten years, discuss the principal approaches used depending on the age of the patient, the amount of adipose tissue, the lower lid tarsal and muscular laxity and the quality of the skin excess. In the lower eyelid they emphasize the value of the transconjunctival approach in young and or coloured people and the use of a cutaneo-muscular flap in the classical technique. In the upper eyelid, they combine the skin excision with an orbicularis muscle strip and in old people with suspension of the lateral canthus. A wise selection of these various approaches avoids the rare complications (ectropion and scleral show) because blepharoplasty must be considered to be a "variable geometry" operation.

Adult↗

PubMed1990

["Delta" cartilaginous graft in secondary or post traumatic rhinoplasty].

The authors study some cases of surgical revision in post traumatic or secondary rhinoplasty. Cartilaginous grafts with temporal superficialis fascia are recommended. The removal of ear cartilage is used by a posterior approach for the concha cartilage associated with a septum or an alar cartilage removal. They describe the Delta graft associating a concha cartilage supported by a prop (auricular or septal) to repair a loss of substance from the middle or lower third of the nasal pyramid.

Adult↗

PubMed1990

[Blepharoplasties. Different techniques of surgery].

The authors, reviewing their own experience of Blepharoplasty (92 cases) since ten years, discuss the principal approaches used depending on the age of the patient, the amount of adipose tissue, the lower lid tarsal and muscular laxity and the quality of the skin excess. On the lower eye lid they emphasize the interest of the transconjunctival approach in young an or coloured people and they undermine a cutaneo-muscular flap in the classical technique. On the upper eye lid, they combine the skin excision with an orbicular muscle strip and in old people with a suspension of the lateral canthus. A good choice between these different approaches avoid the rare complications (ectropion and scleral show) because blepharoplasty must be considered like a "variable geometry" operation.

Age Factors↗

PubMed1989

Different technical approaches for blepharoplasty in eyelid rejuvenation surgery.

The authors have reviewed their clinical experiences with 92 cases of blepharoplasties treated during the past 10 years and discuss the principal approaches used, depending on the age of the patient, the amount of adipose tissue present, the degree of lower lid tarsal and muscle laxity present, and the quality of the skin excess encountered. On the upper eyelid, skin excision is combined with an orbicular muscle strip and in older patients a suspension of the lateral canthus. On the lower eyelid the transconjunctival approach is emphasized in young and or colored patients, using an undermined musculocutaneous flap in the classical technique. A good choice between these different approaches avoids the rare complications of ectropion and scleral show because the procedure used is considered to be a variable "geometric" operation.

Blepharoptosis↗