[Focus on the activity of the European group of radiobiology. NCI TPOT study T92-0045. 9 June 1995, Lyon].
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Biopsy↗
Biomedical subjects
P Coucke
Publications and source records attributed to P Coucke.
Linkage of autosomal dominant hearing loss to the short arm of chromosome 1 in two families.
BACKGROUND: At least half of the cases of profound deafness of early onset are caused by genetic factors, but few of the genetic defects have been identified. This is particularly true of the most common hereditary forms of deafness, which occur in the absence of any associated syndrome. METHODS: We studied a large Indonesian family in which hearing loss was inherited in an autosomal dominant pattern. The hearing loss first affects the high frequencies during the teens or 20s and becomes profound within 10 years. To locate the responsible gene, we performed genetic-linkage analysis, using microsatellite markers distributed over the entire genome. We then performed linkage analyses in an American family and a Dutch family with similar patterns of hereditary hearing loss. RESULTS: In the extended Indonesian family, a gene linked to deafness mapped to chromosome 1p, with a multipoint lod score of more than 7. In the American family, deafness was linked to the same locus on chromosome 1p, with a multipoint lod score of more than 5. In the Dutch family, however, this locus was ruled out. The flanking markers D1S255 and D1S211 defined a region of 6 cM on chromosome 1p that is likely to contain the gene associated with deafness in the first two families. CONCLUSIONS: In some families with early-onset autosomal dominant hearing loss, the responsible gene is on chromosome 1p.
Adolescent↗
Localization of a new type of X-linked liver glycogenosis to the chromosomal region Xp22 containing the liver alpha-subunit of phosphorylase kinase (PHKA2).
We describe here a new type of X-linked liver glycogen storage disease. The main symptoms include liver enlargement and growth retardation. The clinical and biochemical abnormalities of this glycogenosis are similar to those of classical X-linked liver glycogenosis due to phosphorylase kinase deficiency (XLG). However, in contrast to patients with XLG, the patients described here have no reduced phosphorylase kinase activity in erythrocytes and leukocytes, and no enzyme deficiency could be found. Linkage analysis of four families with this X-linked type of liver glycogenosis assigned the disease gene to Xp22. Lod scores obtained with the markers DXS987, DXS207, and DXS999 were 3.97, 2.71, and 2.40, respectively, all at 0% recombination. Multipoint linkage analysis localized the disease gene between DXS143 and DXS989 with a maximum lod score of 4.70 at theta = 0, relative to DXS987. As both the classical XLG gene and the liver alpha-subunit of PHK (PHKA2) are also located in Xp22, this variant type of XLG may be allelic to classical XLG, and both diseases may be caused by mutations in PHKA2. Therefore, we propose to classify XLG as XLG type I (the classical type of XLG) and XLG type II (the variant type of XLG).
Adolescent↗
MASA syndrome is due to mutations in the neural cell adhesion gene L1CAM.
MASA syndrome is a recessive X-linked disorder characterized by mental retardation, adducted thumbs, shuffling gait, aphasia and, in some cases, hydrocephalus. Since it has been shown that X-linked hydrocephalus can be caused by mutations in L1CAM, a neuronal cell adhesion molecule, we performed an L1CAM mutation analysis in eight unrelated patients with MASA syndrome. Three different L1CAM mutations were identified: a deletion removing part of the open reading frame and two point mutations resulting in amino acid substitutions. L1CAM, therefore, harbours mutations leading to either MASA syndrome or HSAS, and might be frequently implicated in X-linked mental retardation with or without hydrocephalus.
Aphasia↗
Effects of alpha-hederin, a saponin extracted from Hedera helix, on cells cultured in vitro.
In this work, we have analysed the effects of alpha-hederin, a monodesmosidic triterpenoid saponin isolated from Hedera helix, on mouse B16 melanoma cells and non-cancer mouse 3T3 fibroblasts cultured in vitro. Our results indicate that, in a serum-free medium, alpha-hederin is cytotoxic and inhibits proliferation in both cell lines at rather low concentrations (< 5 micrograms/ml) after only 8 hours of treatment. Its cytotoxicity decreases in the presence of serum in which BSA seems to be able to bind the saponin. alpha-Hederin also induces vacuolization of the cytoplasm and membrane alterations leading to cell death.
3T3 Cells↗
X-linked hydrocephalus and MASA syndrome present in one family are due to a single missense mutation in exon 28 of the L1CAM gene.
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Abnormalities, Multiple↗
Identification of a 5' splice site mutation in intron 4 of the L1CAM gene in an X-linked hydrocephalus family.
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Base Sequence↗
Primary cerebral lymphoma. A retrospective study of 27 cases.
PURPOSE: Primary cerebral lymphoma is a rare disease. The aim of this study is to compare the survival of the patients treated with radiotherapy alone vs. patients treated with a combined schedule of radio-chemotherapy. Our results will be compared with currently published data and main prognostic factors will be briefly discussed. PATIENTS AND METHODS: Between 1974 and 1990, 27 cases of primary cerebral lymphoma were diagnosed at our institution. All patients had biopsy-proven disease, the pathology of which was reviewed for this study. RESULTS: The overall median survival time was 24 months and one-, two- and three-year overall survival was 59, 46 and 29% respectively. The median radiation dose was 46 Gy, ranging from 19.5 to 60 Gy. The median dose per fraction was 2 Gy (ranging from 1.61 to 3 Gy). The median elapsed treatment time was 32 days (ranging from three to 45 days). We were not able to demonstrate any statistically significant difference between patients who received radiotherapy alone (n = 14, median survival time = 24 months) and those who received a combination of chemotherapy and radiotherapy (n = 11, median survival time = 30 months), (p = 0.4). Prognostic factors of survival were tested using a univariate analysis (Wilcoxon test). Parameters such as mass appearance (unilobular, p = 0.048), performance status at the time of the diagnosis (0 to 1, p = 0.014), and CT imaging (hypodense, p = 0.043) influenced positively survival. Centroblastic histology (Kiel) was found associated with a negative prognosis (p = 0.043). CONCLUSION: In our experience, there is no statistically significant difference of survival between patients treated with radiotherapy alone or with a combined treatment of radio-chemotherapy. Other prognostic factors of survival were discovered, although the analysis was univariate, due to the limited number of patients. Multicentric prospective studies should be elaborated in order to optimize the treatment of this disease.
Brain Neoplasms↗
Mapping of a liver phosphorylase kinase alpha-subunit gene on the mouse X chromosome.
Phosphorylase kinase (PHK) is a regulatory enzyme of the glycogenolytic pathway composed of a complex of four subunits. We recently mapped the muscle alpha-subunit gene (Phka) to the mouse X chromosome in a region syntenic with the proximal long arm of the human X chromosome and containing the human homologue of this gene, PHKA. We now report the mapping of the liver alpha-subunit gene to the telomeric end of the mouse X chromosome. This mapping position would suggest a location for the human liver alpha-subunit gene on the proximal short arm of the X chromosome, a region recently implicated in X-linked liver glycogenosis (XLG).
Animals↗
Molecular study of chromosome 15 in 22 patients with Angelman syndrome.
DNA studies in 22 families with Angelman syndrome (AS) were performed using the chromosome 15 marker loci D15S9, D15S10, D15S11, D15S12, D15S13, D15S18, D15S24, D15S86, the alpha-actin gene and the GABA beta 3 receptor gene (GABRB3). Uniparental disomy of chromosome 15 was excluded in all patients. Eighteen AS patients (82%) showed a molecular deletion of chromosome 15q11-q13 with one or more of these markers. No duplications of junction fragments, bridging deletions or duplication breakpoints were observed. The GABRB3 gene was deleted in all deletion-positive patients tested. Analysis of maternal DNA indicated that each deletion was a de novo event. All deletions were of maternal origin; this is in agreement with genomic imprinting in AS.
Actins↗
An immunohistochemical and histochemical study of cytokeratin, involucrin and transglutaminase in seborrhoeic keratosis.
The mode of differentiation of seborrhoeic keratoses was investigated by immunohistochemical staining using cytokeratin (CK) polypeptide-specific monoclonal antibodies and an antibody specific for the particulate form of epidermal transglutaminase (ETgase), and by applying an anti-human involucrin serum. The role played by (E)Tgase was further evaluated using an activity assay based on the covalent attachment of monodansylcadaverine. Samples of uninvolved epidermis served as reference tissue. CK reactivities suggested that seborrhoeic keratoses is a hyperproliferative disease with an epidermal CK composition. CK5 and CK14 were prominent markers of basal and basaloid keratinocytes, whereas a decrease in staining occurred in advanced maturation stages and areas of terminal keratinization. In contrast, CK1 and CK10 were prominent markers of suprabasaloid differentiation stages and produced complementary stainings to those of CK5 and 14. Generally, CK10 staining was more impressive than CK1 staining and seemed to start before CK1 staining. In contrast to CK10 staining, cornified areas lost CK1 reactivity. These staining patterns were similar to those observed in uninvolved reference tissues. The epidermal CK subset was further supplemented with the 'hyperproliferative' CK6 and 16 which occur sequentially. Positive staining for CK6 was noted from basal and proximal basaloid cells onwards, whereas distal basaloid cells additionally showed CK16 staining. The presence of other non-epidermal CK polypeptides could not be shown. The competence for other differentiation markers belonging to the group of (E)Tgase and cornifying cell membranes also evolved with a typical epidermal pattern. (E)Tgase activity was restricted to advanced and terminal stages of keratinization and was dual in nature, i.e. a diffuse cytoplasmic staining occurred together with a prominent staining of cornifying cell membranes.(ABSTRACT TRUNCATED AT 250 WORDS)
Humans↗
A duplication in the L1CAM gene associated with X-linked hydrocephalus.
Recently, a mutation in the gene for the neural cell adhesion molecule L1CAM, located at chromosome Xq28, was found in a family with X-linked hydrocephalus (HSAS). However, as the L1CAM mutation could only be identified in one HSAS family, it remained unclear whether or not L1CAM was the gene responsible for HSAS. We have conducted a mutation analysis of L1CAM in 25 HSAS families. The mutation reported previously was not found in any of these families. In one family, however, a 1.3 kilobases (kb) genomic duplication was identified, cosegregating with HSAS and significantly changing the intracellular domain of the L1CAM protein. These results confirm that L1CAM is the HSAS gene.
Alternative Splicing↗
X-linked liver glycogenosis: localization and isolation of a candidate gene.
X-linked phosphorylase kinase (PHK) deficiency causes X-linked liver glycogenosis (XLG) which is the most frequent liver glycogen storage disorder in man. Recently we assigned XLG to the Xp22 chromosomal region by linkage analysis in two families segregating XLG. In this study a further localization of XLG in Xp22 was performed by extending the number of Xp22 markers, by extension of the number of family members from the two families of our previous study and by linkage analysis in four additional XLG families. Two-point linkage analysis revealed lod scores of 4.60, 5.73, 5.28, 8.62 and 5.14 for linkage between XLG and the DNA markers pXUT23 and pSE3.2-L(DXS16), pD2(DXS43), pTS247-(DXS197) and pPA4B(DXS207), respectively, all at 0% recombination. Linkage heterogeneity was not observed in this set of families. Multipoint linkage analysis increased the lod score for linkage between XLG and Xp22 to 16.79 relative to DXS197/DXS207. The position of the XLG gene was confirmed by analysis of recombinational events locating the XLG gene between DXS85 and DXS41. The XLG gene could not be mapped more precisely in this chromosomal region of approximately 20cM because of the absence of recombinational events between the XLG gene and the Xp22 markers. As we have previously shown that the rabbit liver alpha subunit of PHK (PHKA2) hybridizes to human Xp22, we isolated a human PHKA2 cDNA from a human hepatoma lambda gt11 cDNA library. Fluorescent in situ hybridization mapped human PHKA2 to Xp22. As this physical mapping coincides with the genetic mapping of XLG by linkage analysis, PHKA2 most probably harbours the mutation(s) responsible for XLG.
Amino Acid Sequence↗
Fine genetic localization of the gene for autosomal dominant polycystic kidney disease (PKD1) with respect to physically mapped markers.
PKD1, the gene for the chromosome 16-linked form of autosomal dominant polycystic kidney disease, has previously been genetically mapped to an interval bounded by the polymorphic loci Fr3-42/EKMDA2 distally and O327hb/O90a proximally. More recently, 26.6PROX was identified as the closest proximal flanking locus. We set out to refine the localization of PKD1 by identifying a series of single recombinant events between the flanking markers Fr3-42/EKMDA2 and O327hb/O90a and analyzing them with a new set of polymorphic loci that have been physically mapped within the PKD1 interval. We identified 11 such crossovers in eight families; 6 of these fell into the interval between GGG1 and 26.6PROX, a distance of less than 750 kb. Three of these crossovers placed PKD1 proximal to GGG1 and two crossovers placed PKD1 distal to 26.6PROX. Both of the latter also placed PKD1 telomeric to a locus 92.6SH1.0, which lies 200-250 kb distal to 26.6PROX. The sixth recombinant, however, placed the disease mutation proximal to the locus 92.6SH1.0. Several possible explanations for these observations are discussed. An intensive study to locate deletions, insertions, and other chromosomal rearrangements associated with PKD1 mutations failed to detect any such abnormalities. Thus we have defined, in genetic and physical terms, the segment of 16p13.3 where PKD1 resides and conclude that a gene-by-gene analysis of the region will be necessary to identify the mutation(s).
Chromosome Mapping↗
Immunohistochemical analysis of the cytokeratin expression in middle ear cholesteatoma and related epithelial tissues.
Immunohistochemical investigations were carried out to determine the pattern of cytokeratin (CK) expression in middle ear cholesteatoma and related epithelia. Using monoclonal antibodies specific for CK chains and the indirect immunoperoxidase technique, we examined 10 CK polypeptides for expression. The external stratified squamous epithelium of the tympanic membrane generally expressed CKs 5, 10, and 14. In addition, basal keratinocytes in the annular region of the pars tensa expressed CK 19 (a simple epithelium marker), while suprabasally the hyperproliferative marker CK 16 was expressed. These data reflect the unusual proliferative nature of this region. The unexpected appearance of CK 16 (known to have a limited distribution in healthy epidermis) clearly relates to its expression in the neighboring deep meatus. The medial simple epithelium of the eardrum revealed mucosal CKs 7, 8, 14, 18, and 19. Acquired cholesteatoma lesions, besides CKs 5, 10, and 14, consistently expressed CK 16 in suprabasal layers. These results constitute the first direct molecular evidence for the hyperproliferative nature of the cholesteatoma matrix. Overall, our CK data suggest that aural cholesteatoma lesions and epidermal tissue in this area are related. However, they do not explain the mechanism(s) by which the eardrum or meatal epithelia might invade the middle ear cavity. Congenital cholesteatomas expressed CKs 5, 10, 14, and 16 equally. These CK data do not support the idea of a metaplastic origin from middle ear mucosa; instead, they suggest activation of an ectodermal rest in the middle ear cavity.
Adult↗
Further localization of X-linked hydrocephalus in the chromosomal region Xq28.
X-linked hydrocephalus (HSAS) is the most frequent genetic form of hydrocephalus. Clinical symptoms of HSAS include hydrocephalus, mental retardation, clasped thumbs, and spastic paraparesis. Recently we have assigned the HSAS gene to Xq28 by linkage analysis. In the present study we used a panel of 18 Xq27-q28 marker loci to further localize the HSAS gene in 13 HSAS families of different ethnic origins. Among the Xq27-q28 marker loci used, DXS52, DXS15, and F8C gave the highest combined lod scores, of 14.64, 6.53 and 6.33, respectively, at recombination fractions of .04, 0, and .05, respectively. Multipoint linkage analysis localizes the HSAS gene in the telomeric part of the Xq28 region, with a maximal lod score of 20.91 at 0.5 cM distal to DXS52. Several recombinations between the HSAS gene and the Xq28 markers DXS455, DXS304, DXS305, and DXS52 confirm that the HSAS locus is distal to DXS52. One crossover between HSAS and F8C suggests that HSAS gene to be proximal to F8C. Therefore, data from multipoint linkage analysis and the localization of key crossovers indicate that the HSAS gene is most likely located between DXS52 and F8C. This high-resolution genetic mapping places the HSAS locus within a region of less than 2 Mb in length, which is now amenable to positional cloning.
Blotting, Southern↗
[Radiation protection of the small intestine in the lesser pelvis using an inflatable silicon prosthesis].
The combination of radiotherapy and surgery plays a major role in treating pelvic cancer. However, this technique is chiefly limited by the radiosensitivity of the small bowel following postoperative radiotherapy. In this situation the small bowel is not protected because of its lack of mobility. A radioprotective prosthesis is presented which is readily removable and whose purpose is to push the small bowel out of the pelvis during radiotherapy, thus protecting it from radiotherapy. If required, a simple system allows the prosthesis to be emptied and refilled between courses of radiotherapy, if required, without reoperation. This technique has been used in 4 patients: 2 had rectal carcinoma secondary to ulcerative colitis in one case and to Crohn's disease in the other; the other 2 cases were recurrent rectal carcinoma, one of which was partially resectable. When radiotherapy was completed the prosthesis could be deflated and removed through a short incision under local anesthetic. In the medium term, no small bowel complications were observed in spite of high-dose radiotherapy. When used for radiosensitive pelvic tumors, this technique combines low cost and ease of use with very low morbidity and the possibility of administering high-dose radiotherapy.
Adenocarcinoma↗
Frequency of the phenylalanine deletion (delta F508) in the CF gene of Belgian cystic fibrosis patients.
Cloning and sequencing of the CF gene has identified a three-base-pair deletion (delta F508) responsible for CF in the majority of CF patients (Kerem et al. 1989). We have used the polymerase chain reaction with oligonucleotide primers bridging the delta F508 deletion to analyze the presence or absence of this mutation in the Belgian CF population. The delta F508 mutation was present in 80% (57 on 71) of CF chromosomes from 36 unrelated Belgian CF families from the region of Antwerp. This mutation was associated with haplotype B for the KM.19-XV-2c RFLPs as 93% (53 on 57) of the CF chromosomes with the delta F508 mutation carried haplotype B.
Belgium↗