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L Messiaen

Publications and source records attributed to L Messiaen.

47 records · Page 3Linked to original sources
PubMed1997

Characterisation of two different nonsense mutations, C6792A and C6792G, causing skipping of exon 37 in the NF1 gene.

Neurofibromatosis type 1 (NF1), characterised by peripheral neurofibromas, café-au-lait spots and iris Lisch nodules, is one of the most common inherited disorders. We have analysed exons 35 to 49 in 21 unrelated NF1 patients using reverse transcription-polymerase chain reaction and protein truncation analysis. In two unrelated patients we found skipping of exon 37 at the cDNA level. Sequence analysis of genomic DNA revealed the presence of a C6792A transversion in one patient and a C6792G transversion in a second patient; both transversions change the codon for tyrosine to a nonsense codon. Sequencing of the exonic sequences as well as the branch sites, and the 3' and 5' splice sites of exons 36, 37 and 38 did not reveal any additional sequence abnormality. This is the first report showing that nonsense mutations in the NF1 gene can induce the skipping of a constitutive exon.

Alleles↗
PubMed1996

Novel frameshift mutation in a heterozygous woman with Fabry disease and end-stage renal failure.

UNLABELLED: It is generally accepted that Fabry disease (angiokeratoma corporis diffusum) is an X-linked disorder resulting from the deficient activity of the lysosomal enzyme alpha-galactosidase. In males, the enzymatic defect leads to accumulation of glycosphingolipids, particularly in the kidney which causes end-stage renal disease. We report here a woman who presented in 1987 with focal and segmental glomerulosclerosis and required hemodialysis 4 years later when her son was evaluated for proteinuria. In these patients morphologic, biochemical, and genetic investigations were performed to explore the possibility of a hereditary renal disorder. Ultrastructural examination of the son's renal biopsy specimen revealed lamellated osmiophilic inclusions in the glomeruli, typical of Fabry disease. Four months after kidney transplantation in the mother, a graft biopsy specimen also revealed dense lamellated inclusions on electron microscopy. The leukocyte alpha-galactosidase activity was 0.008 mumol/min.10(9) cells in the son and 0.070 in the mother (range 0.100-0.500 mumol/min.10(9) cells). The diagnosis of Fabry disease was confirmed in both patients by the identification by DNA sequencing of a novel mutation in the alpha-galactosidase gene: one single base pair deletion in exon 3 (7317delA). IN CONCLUSION: (1) end-stage renal disease may occur in heterozygous women with Fabry disease; (2) morphologic lesions due to glycosphingolipid accumulation may be observed in the renal allograft after transplantation, and (3) DNA analysis confirmed the diagnosis by demonstrating a frameshift mutation, which has as yet not been reported.

Adult↗
PubMed1996

Refined genetic and physical mapping of BPES type II.

BPES is a genetic disorder including blepharophimosis, ptosis of the eyelids, epicanthus inversus and telecanthus. Type I is associated with female infertility, whereas type II presents without other symptoms. Both types I and II occur sporadically or are inherited as an autosomal dominant trait. We present a molecular genetic and cytogenetic study in a large four-generation Belgian family with BPES type II. Karyotype analysis on high-resolution banded chromosomes yielded normal results. Fluorescence in situ hybridization (FISH) with cosmid probes spanning 3q22-q24 revealed normal hybridization patterns. Sixteen polymorphic CA repeats encompassing region 3q13-q25 were analysed. Linkage analysis in this large four-generation family provides conclusive evidence for the presence of a BPES gene in this region. Two-point lod scores greater than 3.0 between the disease and the following markers were seen: D3S1589 (4.67), D3S1292 (3.52), D3S1290 (3.59) and D3S1549 (3.65). By FISH, D3S1290, D3S1292 and D3S1549 were assigned to chromosome 3q23 using YACs positive for these markers.

Belgium↗
PubMed1991

Spontaneous acquisition of tumorigenicity and invasiveness by mouse lens explant cells during culture in vitro.

The lens of the eye is one of the rare organs in which tumors do not occur spontaneously. It therefore appeared to us that lens cells would not present the background of spontaneous transformation toward malignancy found with many other cell cultures. We have cultured C3H/HeA mouse lens explant (MLE) cells for 70 wk and analyzed changes in malignancy-related phenotypes in function of the number of passages. In vitro, we studied morphology, colony forming efficiency on tissue culture plastic substrate (CFEtc) and in soft agar, population doubling time, saturation density, and invasiveness into precultured chick heart fragments. In vivo, tumorigenicity, invasion, and metastasis were analyzed after injection of cell suspensions subcutaneously and intraperitoneally, after implantation of cells aggregated to collagen sponges under the renal capsule and after implantation of cell aggregates subcutaneously into the tail and into the pinna. The CFEtc, population doubling time, and saturation density increased as the number of passages of culture in vitro increased, but colony formation in soft agar was never observed. MLE cells till passage 16 were not invasive in vitro, but hereafter consistently were found to be invasive. After about 17 passages, corresponding to 25 wk of culture, MLE cells acquired the capacity to form tumors in syngeneic mice. These tumors were invasive but metastases were not observed. We concluded that MLE cells acquired in an apparently spontaneous way a number of malignancy-related phenotypes, without, however, reaching the stage of metastasis.

Animals↗
PubMed1987

Pathology of tumours produced in syngeneic Fischer rats by fibroblast-like cells before and after transfection with oncogenes.

Fischer rat cells before and after transfection with immortalizing and transforming genes produced tumours after s.c., i.p., or i.v. injection of cell suspensions and after s.c. implantation of cellular aggregates in the tail of syngeneic rats. Tumours were described histologically as fibrosarcoma-like. Virtually all tumours were considered macroscopically to be invasive because they adhered to the neighbouring tissues; in many tumours invasion was confirmed microscopically. All types of cells produced lung colonies (artificial metastases) after i.v. injection. Spontaneous metastases (from a primary tumour) were found with some tumours produced by cells before as well as after transfection. Differences in metastasis between various cell types could not be ascribed to variations in the periods of observation, in the minimum tumour-bearing periods, in the latency periods, or in the volume of primary tumours. We concluded that local invasion and spontaneous metastasis are usefull for the characterization of malignancy in experimental fibrosarcoma-like tumours. Since Fischer rat cells produced invasive and sometimes metastatic tumours before transfection, the present data do not show a rôle of immortalizing and transforming genes in the acquisition of invasiveness and metastatic capability.

Abdominal Neoplasms↗
PubMed1986

Invasiveness and metastatic capability of rat fibroblast-like cells before and after transfection with immortalizing and transforming genes.

Invasion in vitro and in vivo and spontaneous metastasis was investigated in cell lines before and after introduction of immortalizing (polyoma large-T and activated myc) genes and of transforming (polyoma middle-T and activated ras) genes in Fischer rat cells. Invasion in vitro was tested by confrontation of rat cells with embryonic chick heart fragments in organ culture. Invasion in vivo and metastasis was evaluated in nude mice and in syngeneic rats after injection of cells i.p. or s.c. in the flank and after implantation of cell aggregates s.c. in the tail. Rat cells were also analyzed for the presence of myc oncogenes, and for the expression of ras oncogenes. Cells from primary or low passage rat embryo (REF) cells were not invasive in vitro and did not produce tumors in vivo. Cell lines (LTRAT1, LTaRAT1) derived from REF cultures after transfection with plasmids encoding polyoma large-T antigens, behaved like REF cells. Cell lines (REFpEJgpt4, REFpEJmycN7) established from REF cultures after transfection with either a plasmid encoding an activated human ras protein or with the latter plasmid plus one containing an activated myc gene, were invasive in vitro and in vivo and produced invasive and metastatic tumors in syngeneic rats. Cell lines (FR3T3) established in an apparently spontaneous way were invasive in vitro and produced invasive tumors in vivo without metastasis. Derivatives of FR3T3 (FRLT1, MTT4, MMC1, and PyT21) transfected with plasmids encoding one or more of the polyoma antigens, differed from FR3T3 cells by a shorter latency period of tumor formation (less than 1 versus 1 to 3 weeks). Like FR3T3 tumors, FRLT1, MTT4, MMC1, and PyT21 tumors were invasive but not metastatic. Other spontaneously established lines (Rat1) were invasive and metastatic. Cells (Rat1pEJ6.6) derived from Rat1 cultures after transfection with a plasmid encoding an activated ras protein, showed shorter tumor latency periods (less than 1 versus 7 weeks). A thymidine kinase deficient Rat1 derivative (Rat2) was not invasive in vitro but produced invasive and metastatic tumors in vivo with long (9 to 21 weeks) latency periods. Rat2pT24B4 cells derived by us from Rat2 cells after transfection with a plasmid containing a mutated human ras gene (pT24), were invasive in vitro and in vivo as were cells derived from Rat2 tumors. We conclude from our experiments that invasiveness and metastatic capability are often acquired by established REF-derived cell lines in an apparently spontaneous way.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMedDate not supplied

Identification of two different mutations causing protein S deficiency in two unrelated Belgian families using a nonisotopic scanning and sequencing method.

Hereditary protein S deficiency is a risk factor for developing recurrent venous thromboembolic disease and is caused by a defect in the protein S 1 (PROS1) gene. Identification of the mutation in the PROS1 gene can overcome diagnostic uncertainty in family members with borderline protein S levels. We describe a novel nonisotopic method for molecular diagnosis of protein S deficiency, using fluorescein-labeled amplification and sequencing primers. As a first step, all exons of the PROS1 gene are selectively amplified, and heteroduplex analysis is performed. As a second step, all exons are analyzed by direct sequencing. Using this method, we have characterized the molecular defect in two Belgian families with hereditary protein S deficiency type I: a frameshift mutation in exon XIV (1881insTC) and a missense mutation caused by a T-to-C transition, resulting in substitution of Leu405 by Pro (L405P).

Adolescent↗
PubMedDate not supplied

Prevalence of the Cys282Tyr and His63Asp mutation in Flemish patients with hereditary hemochromatosis.

UNLABELLED: Recently Feder et al. have identified the gene responsible for hereditary hemochromatosis; it is located 3 Mbp telomeric of the MHC region on chromosome 6p and is called the HFE gene. The majority of the patients with hemochromatosis harbour the same missense mutation, Cys282Tyr. A second missense mutation (His63Asp) of which the significance is less clear, has also been described. To our knowledge the percentage of these two missense mutations in Flemish hemochromatosis patients is not known. MATERIALS AND METHODS: Forty nine (49) unrelated patients with the clinical diagnosis of hemochromatosis were screened for the two missense mutations. The missense mutations were diagnosed with a PCR technique. RESULTS: Of the 49 patients, 46 patients were homozygous for the Cys282Tyr mutation (94%), 2 were heterozygous (4%) and 1 carried two normal alleles (2%). Of the 3 patients not homozygous for the Cys282Tyr mutation, 3 were heterozygous for the His63Asp mutation (2 patients were 'compound heterozygotes'). DISCUSSION: The percentage of homozygotes (Cys282Tyr) in a Flemish hemochromatotic population is comparable with the figures published in the literature. The second missense mutation (His63Asp) could be of importance in association with the Cys282Tyr missense mutation.

Amino Acid Substitution↗