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Biomedical subjects

F Escande

Publications and source records attributed to F Escande.

At least 19 recordsLinked to original sources
PubMed2006

[Genetics and orthopedics: genetic implications of congenital limb abnormalities].

Limb malformations are frequent. These malformations are isolated or associated with anomalies of other developmental fields and accurate diagnostic is essential for prognosis evaluation, treatment and genetic counseling. Animal embryology and molecular biology techniques, have given us a better understanding of the processes of growth and patterning of the limb buds. The key genes that are involved in these processes have been identified and their interactions recognized. Human genetics has been able to identify, or at least localize, several genes implicated in limb development. We here review the present knowledge on these genes and their mutations responsible for limb anomalies.

Extremities↗
PubMed2004

Mapping of SOMU1 and M1 epitopes on the apomucin encoded by the 5' end of the MUC5AC gene.

We have developed 11 monoclonal antibodies (MAbs) against human gastric mucin, (1-13M1, 2-11M1, 2-12M1, 9-13M1, 58M1, 19M1, 21M1, 45M1, 463M, 589M, 62M1), which specifically stained by immunohistochemisty both the human gastric surface mucosa and colon adenoma. Among them, five (19M1, 21M1, 463M, 589M, 62M1) immunoreacted with the peptide encoded by the 3' region of the MUC5AC gene (Nollet et al: Int J Cancer 2002;99:336-343). In this study, we identified in the 5' region of this gene the nucleotide fragments encoding peptides immunoreacting with three other anti-M1 MAbs (1-13M1, 2-11M1 and 9-13M1), as well as the SOMU1 MAb (Sotozono et al: J Immunol Methods 1996;192:187-196). 1-13M1 MAb immunoreacts with peptides, including the Cys 2 and Cys 4 domains. The SOMU1 MAb recognized the Cys 5 domain, and the MAbs 2-11M1 and 9-13M1 the globular D1/D2 and D3 domains, respectively. Using serial sections of the mucosae adjacent to colon adenocarcinomas and colon adenomas, we observed that the anti-M1 and anti-SOMU1 MAbs displayed the same immunostaining patterns. The three anti-M1 MAbs (2-12M1, 58M1, and 45M1) did not react with the products of the MUC5AC gene tested until now. The MUC5AC apomucin is now well characterized by MAbs immunoreacting against seven different epitopes belonging to the different main cystein globular domains of this macromolecule. Such antibodies are useful tools for studying the biosynthesis, polymerization, and degradation of mucin.

Animals↗
PubMed2001

Normal respiratory mucosa, precursor lesions and lung carcinomas: differential expression of human mucin genes.

Mucins are glycoproteins synthesized by epithelial cells and thought to promote tumor-cell invasion. Eight human mucin genes have been well characterized: MUC2, MUC5AC, MUC5B, MUC6 map to 11p15.5 and encode secretory gel forming mucins while MUC1, MUC3, MUC4, MUC7 are scattered on different chromosomes and encode membrane-bound or secreted mucins. The expression pattern of the mucin genes is complex in normal airways involving six genes, mainly MUC5AC and MUC5B in mucus-producing cells and MUC4 in a wide array of epithelial cells. MUC5AC overexpression in metaplasia, dysplasia and normal epithelium adjacent to squamous cell carcinoma provides additional arguments for a mucous cell origin of preneoplastic squamous lesions. MUC5AC and MUC5B expression is related to mucus formation in adenocarcinomas. Mucinous bronchioloalveolar carcinoma (BAC) has a particular pattern of mucin gene expression indicating that it has sustained a well-differentiated phenotype similar to the goblet cell, correlated with distinctive features i.e. a noninvasive pattern and a better prognosis than nonBACs. MUC4 is the earlier mucin gene expressed in the foregut, before epithelial differentiation and is expressed independently of mucus secretion both in normal adult airways and carcinomas. These findings are in favor the histogenetic theory of non-small-cell carcinoma originating from a pluripotent mucous cell.

Gene Expression Regulation↗
PubMed2001

Structural organization and classification of the human mucin genes.

The cells of living organisms in contact with the external environment are constantly attacked by different kinds of substances such as micro-organisms, toxins, and pollutants. With evolution, defense mechanisms, such as the secretion of mucus has been developed. Mucins are the main components of mucus. They are synthesized and secreted by specialized cells of the epithelium and in some case, by non mucin-secreting cells. Little was known about the structure of mucins until a decade ago. This is principally due to heavy glycosylation of mucins, which complicated their analysis. With the application of molecular biological methods, structures of the mucin core peptides (apomucins) are beginning to be elucidated. A total of eleven human mucin (MUC) genes have been identified and numbered in chronological order of their description: MUC1-4, MUC5AC, MUC5B, MUC6-8, and MUC11-12. Of these, the complete cDNA sequence are published only for six mucins MUC1, MUC2, MUC4, MUC5B, MUC5AC, and MUC7. Human mucin genes, in general, show three common features: I) a nucleotide tandem repeat domain; II) a predicted peptide domain containing a high percentage of serines and threonines; III) complex RNA expression. The tandem repeats in mucins make up the majority of the backbone. Related to their structure, mucins can be classified in three distinct sub-families: gel-forming, soluble, and membrane-bound. Each member from one family possesses common characteristics and probably specific functions. For a long time, they were thought to have the unique function of protecting and lubricating the epithelial surfaces. The study of the mucins structure as well as the relationship between structure and function show that mucins also possess other important functions, such as growth, direct implication in the fetal development, the epithelial renewal and differentiation, the epithelial integrity, carcinogenesis, and metastasis. This review presents the actual knowledge on the mucins structure and the best-characterized function related to their structure.

Genes↗
PubMed2001

Human mucin gene MUC5AC: organization of its 5'-region and central repetitive region.

Human mucin gene MUC5AC is clustered with MUC2, MUC5B and MUC6 on chromosome 11p15.5. We report here the full length cDNA sequence upstream of the repetitive region of human MUC5AC. We have also determined the sequence of its large central tandem repeat array. The 5'-region reveals high degree of sequence similarity with MUC2 and MUC5B and codes for 1336 amino acids organized into a signal peptide, four pro-von Willebrand factor-like D domains (D1, D2, D' and D3) and a short domain which connects to the central repetitive region. In the central region, 17 major domains have been identified. Nine code for cysteine-rich domains (Cys-domains 1-9) and exhibit high sequence similarity to the cysteine-rich domains described in the central region of MUC2 and MUC5B. Cys-domains 1-5 are interspersed by domains enriched with serine, threonine, and proline residues. Cys-domains 1-9 are interspersed by four domains (TR1-TR4) composed of various numbers of MUC5AC-type repeats. Southern-blot analyses reveal allelic variations both in length and nucleotide sequence. The length polymorphism which is due to variable numbers of tandem repeats is located in TR1 and TR4, whereas a mutation polymorphism detected with TaqI is located in Cys-domain 6. In this study, the organization of MUC5AC has been entirely elucidated showing extensive similarity to the other chromosome 11p15 MUC genes, particularly MUC5B, and providing additional arguments for common evolution from a single ancestral gene.

5' Untranslated Regions↗
PubMed2000

Alternative splicing generates a family of putative secreted and membrane-associated MUC4 mucins.

The MUC4 mucin gene encodes a putative membrane-anchored mucin with predicted size of 930 kDa, for its 26.5-kb allele. It is composed of two regions, the 850-kDa mucin-type subunit MUC4alpha and the 80-kDa membrane-associated subunit MUC4beta. In this study, we cloned and characterized unique MUC4 cDNA sequences that differ from the originally published sequence. Eight alternative splice events located downstream of the central large tandem repeat array generated eight new, distinct cDNAs. The deduced sequences of these MUC4 cDNAs (sv1-MUC4 to sv8-MUC4, the full length cDNA being called sv0-MUC4) provided seven distinct variants, five secreted forms and two membrane-associated forms. Furthermore, two other alternative splicing events located on both sides of the tandem repeat array created two variants, MUC4/Y and MUC4/X, both lacking the central tandem repeat. Therefore, MUC4 can be expressed in three distinct forms, one membrane-bound, one secreted, and one lacking the hallmark feature of mucin, the tandem repeat array. Although no specific function has yet been discovered for the family of proteins putatively produced from the unique MUC4 gene, we suspect that the MUC4 proteins may be implicated in the integrity and renewal of the epithelium.

Alleles↗
PubMed1999

Characterisation of dermonecrotic toxin-producing strains of Pasteurella multocida subsp. multocida isolated from man and swine.

Thirty-six isolates, from man or swine, of Pasteurella multocida subsp. multocida producing (n = 13) or not producing (n = 23) the dermonecrotic toxin (DNT) were studied by numerical analysis, capsular typing and ribotyping. Toxigenic strains were also characterised by restriction fragment length polymorphism (RFLP) of the toxA gene and pulsed-field gel electrophoresis (PFGE). Numerical analysis differentiated the Pasteurella species and subspecies, but did not discriminate between toxigenic and nontoxigenic strains. RFLP demonstrated that toxA was located in a conserved part of the chromosome of all toxigenic strains. Ribotyping provided evidence of a close association between DNT production and one of the six EcoRI ribotypes designated as E2. In contrast, PFGE provided evidence for significant DNA polymorphism amongst the toxigenic strains. Results of phenotypic and genotypic studies suggested that toxigenic strains do not form a clone within the subspecies multocida. No difference was found between toxigenic strains of porcine or human origin by biochemical characterisation, capsular serotyping or genomic typing methods.

Animals↗
PubMed1999

Identification by 16S rDNA fragment amplification and determination of genetic diversity by random amplified polymorphic DNA analysis of Pasteurella pneumotropica isolated from laboratory rodents.

Pasteurella pneumotropica is an opportunistic bacterium frequently isolated from colonies of various laboratory rodents. Identification of this species, including its differentiation into two distinct biotypes (Jawetz and Heyl), is usually based on the use of conventional bacteriologic methods. In this study, a 16S rDNA fragment amplification procedure was developed for use as an alternative method for identification and differentiation of P. pneumotropica. Polymerase chain reaction (PCR) products were two distinctive fragments of 937 and 564 bp specific for biotypes Jawetz and Heyl, respectively. Specificity of PCR products could be achieved by EcoRI cleavage, leading to 596 plus 341-bp and 346 plus 218-bp fragments for each of the amplification products. Use of this procedure confirmed identification of 34 field isolates and allowed definitive identification of some strains that could not have been done by use of bacteriologic examinations. Field isolates subjected to random amplified polymorphic DNA (RAPD) analysis had high genetic diversity among biotype Jawetz strains in contrast to biotype Heyl strains. In conclusion, RAPD could represent an additional means for identification of ambiguous strains of biotype Heyl and a valuable epidemiologic tool for identification of biotype Jawetz strains of P. pneumotropica.

Animals↗
PubMed1997

[Maternal and neonatal Pasteurella multocida infection].

BACKGROUND: Materno-fetal infection due to Pasteurella multocida is rare; it may be severe in the neonate. CASE REPORT: A 27-year old woman was admitted at 37 weeks' gestation with a history of abdominal cramps. Twenty-four hours after delivery, the mother was febrile (40 degrees C) and was given intravenous cefotaxime (2 days), followed by cefpodoxime (15 days). The newborn was febrile and hypotonic 24 hours after birth; he received an infusion of hydroxyethylamidon and was given cefotaxime (3 days), netilmicin (6 days) and amoxicillin (10 days). Pasteurella multocida was isolated from placenta, blood and gastric fluid in the baby and in blood cultures and vaginal swab in the mother. It was established that the mother was bitten by her dog during the pregnancy and wounded a few days before delivery. CONCLUSION: This neonate was infected during the delivery and the source of mother's contamination was easy to determinate: pet animals were kept by the family and there was an history of wounds during her pregnancy.

Adult↗
PubMed1997

Pasteurella caballi infection following a horse bite.

The isolation of Pasteurella caballi from an horse-bite wound in a 56-year-old man is reported. Biochemical characteristics are described and compared with the other species representing the genus Pasteurella. This strain probably represents the first human isolate of P. caballi in France.

Animals↗
PubMed1996

Capnocytophaga canimorsus infections in human: review of the literature and cases report.

Capnocytophaga canimorsus, formerly designated Dysgonic fermenter 2 (DF-2) was first described in 1976; it is a commensal bacterium of dogs and cats saliva, which can be transmitted to man by bite (54% of cases), scratch (8.5%), or mere exposure to animals (27%). We present a review of the clinical and microbiological characteristics of the Capnocytophaga canimorsus infections and 12 cases of infection in France. Over 100 cases of human infections have been reported, mainly septicemia in patients with diminished defences, due to splenectomy (33%), alcohol abuse (24%), immunosuppression (5%). However 40% of septicemia occur in patients with no predisposing conditions. Other infections are less frequent: meningitis, endocarditis, arthritis, pleural and localized eye infections. These infections range from mild to fulminating disease, with shock, respiratory distress, disseminated intravascular coagulation. Dermatological lesions (macular or maculopapular rash, purpura) or gangrene are common. This fastidious Gram-negative bacterium grows slowly on chocolate agar or on heart infusion agar with 5% rabbit blood incubated in 5% CO2. In spite of a great susceptibility of bacteria to antibiotics, the mortality is of 30%. Because of the severity of these infections, taking into account this organism in the management of bites is necessary, especially in patients with predisposing factors.

Adult↗
PubMed1995

Characterization of group EF-4 bacteria from the oral cavity of dogs.

Samples from gingival scrapings of dogs were examined for the presence of CDC Groups EF-4 bacteria. Isolation procedures were performed in 5% sheep blood agar supplemented with thiostrepton and trimethoprim (10 mg/l). Fifty nine EF-4 strains were isolated from 92% of 49 dogs. Among the Group EF-4 bacteria, the majority of isolates belonged to the arginine-negative (biovar "b") Group EF-4 (42 strains recovered in 82% of dogs). Seventeen arginine-positive strains (biovar "a") were recovered only from 35% of dogs. The strains were analysed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The analysis of electrophoretic protein pattern of these bacteria supported the results of conventional testing, confirmed the distinction between the biovars "a" and "b" of Group EF-4 and supported the division of biovar EF-4b into two subgroups of either producing or non-producing acid from gluconate.

Animals↗