Vers une analyse morphologique des structures mobiles des régions orale et pharyngée

Because of the importance of their functional activity, it seems it is now necessary, in dento-facial orthopedy, always to closely into the radiological observation of the mandible structures in the oral and pharyngeal regions, which led us to the elaboration of a plan for the morphological study of those tissues.This study is done on teleradiographics in norma-lateralis, taken at rest position, on children who use to show a lingual interposition between the dental arcades.Its purpose is a morphological reading of the hyo-glosso-pharyngeal structures by means of the linear mensurations and surface studies through a computer table.Cette étude est une ébauche d’application de l’analyse des structures mobiles précédemment décrite. Elle porte sur trois sujets de même âge, de même sexe et de typologie voisine, en posture de repos.Nous y trouvons en particulier des renseignements sur la situation verticale et sagittale des lèvres, de la langue, de l’os hyoïde, du couloir mandibulorachidien, du voile du palais, du couloir pharyngé ainsi que sur les interrelations de ces éléments.Elle comporte d’autre part une approche des relations possibles entre l’organisation de ces structures mobiles et celle des rapports maxillo-mandibulaires

MSH2 and MLH1 mutations in sporadic replication error-positive colorectal carcinoma as assessed by two-dimensional DNA electrophoresis

Replication errors (RER) are frequently seen in both sporadic and hereditary forms of colorectal cancer. In hereditary nonpolyposis colorectal cancer (HNPCC), RER is associated with defects in DNA mismatch repair genes. Two of these genes, MSH2 and MLH1, account for a major share of this cancer syndrome. In order to assess the role of these genes in sporadic RER+ colorectal carcinoma, we have carried out a mutation analysis of MSH2 and MLH1 by two-dimensional (2-D) DNA electrophoresis, including heteroduplexing and separation in a denaturing gradient. All exons were amplified using multiplex PCR and were separated on the basis of both size and base pair composition under a single set of experimental conditions. Exons showing a spot position different from normal were sequenced. In screening 33 unselected, sporadic RER+ colorectal tumors, a germline mutation accompanied by loss of heterozygosity in tumor tissue was found in two patients. They were among the 4 patients out of the 33 screened that were diagnosed before the age of 50 years. In 8 of the remaining 31 tumors (26%), presence of somatic mutations (9 in total) could be demonstrated. While suggesting involvement of other genes in a substantial part of sporadic RER+ colorectal carcinomas, our results also demonstrate a clear role of MSH2 and MLH1 in these sporadic tumors and show that young sporadic RER+ colorectal carcinoma patients have a high probability of germline mutations. This has important implications for genetic testing and management of young colorectal cancer patients and their families. (C) 1997 Wiley-Liss, Inc

DNA mismatch repair gene mutations in 55 kindreds with verified or putative hereditary non-polyposis colorectal cancer

The DNA mismatch repair genes MSH2 and MLH1 have been shown to account for a major share of hereditary non-polyposis colorectal cancer (HNPCC). We searched for germline mutations in these genes in 35 HNPCC kindreds fulfilling the Amsterdam diagnostic criteria and in a further 20 kindreds with an average of four affected members per family but not meeting the formal criteria. We first screened for truncations by reverse transcription (RT)-PCR. If no mutation was found, we screened genomic DNA by a novel application of two-dimensional (2-D) DNA electrophoresis that allows the simultaneous study of all exons of each gene. All abnormalities were followed up by sequencing. Eight different pathogenic germline mutations were found, two in MSH2 and six in MLH1. We report three major conclusions. First, these mutations together accounted for 86% (30/35) of the kindreds meeting the Amsterdam criteria, but only 30% (6/20) of the remaining kindreds, suggesting differences in etiology. Second, MLH1 was involved in >90% (34/36) of kindreds with a known predisposing mutation, suggesting that mutations in the MLH1 gene are responsible for most HNPCC kindreds in Finland. Third, our results indicate that the successive application of RT-PCR and 2-D DNA electrophoresis is a sensitive and efficient method for mutation screening in typical HNPCC