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Biomedical subjects

U Claussen

Publications and source records attributed to U Claussen.

At least 37 records · Page 2Linked to original sources
PubMed2003

Multitude multicolor chromosome banding (mMCB) - a comprehensive one-step multicolor FISH banding method.

Multicolor chromosome banding (MCB) using one single chromosome-specific MCB probe set per experiment was previously reported as powerful tool in molecular cytogenetics for the characterization of all kinds of human marker chromosomes. However, a quick analysis of karyotypes with highly complex chromosomal changes was hampered by the problem that up to 24 MCB experiments were necessary for a comprehensive karyotype description. To overcome that limitation the 138 available region-specific microdissection-derived libraries for all human chromosomes were combined to one single probe set, called multitude MCB (mMCB). A typical fluorescence banding pattern along the human karyotype is produced, which can be evaluated either by transforming these profiles into chromosome region-specific pseudo-colors or more reliably by studying the fluorescence profiles. The mMCB probe set has been applied on chromosomes of normal male and female probands, two primary myelodysplastic syndromes and two solid tumor cell lines. Additionally, a cell line of Gorilla gorilla (GGO) studied previously by single chromosome-specific MCB was reevaluated by the mMCB method. All results were in concordance with those obtained in parallel or by other cytogenetic and molecular cytogenetic approaches indicating that mMCB is a powerful multicolor FISH banding tool for fast characterization of complex karyotypes.

Animals↗
PubMed2003

Evidence for a new microdeletion syndrome in 15q21.

We report on the fourth known case with an interstitial deletion in 15q21. In the present case the breakpoints have been determined by GTG-banding, microdissection and the recently developed multicolor banding (MCB) technique as 15q21.1-q21.3. Common features in all four cases are mental retardation, growth retardation, a beak-like nose with hypoplastic alae nasi and a thin upper lip. Additional frequent features are small hands and feet, hypotonia, low hair implantation, low set ears, clinodactyly and obesity. The possibility that a critical region for a new microdeletion-syndrome is situated in 15q21 is discussed.

Abnormalities, Multiple↗
PubMed2002

Multicolor chromosome banding (MCB) with YAC/BAC-based probes and region-specific microdissection DNA libraries.

Multicolor chromosome banding (MCB) allows the delineation of chromosomal regions with a resolution of a few megabasepairs, i.e., slightly below the size of most visible chromosome bands. Based on the hybridization of overlapping region-specific probe libraries, chromosomal subregions are hybridized with probes that fluoresce in distinct wavelength intervals, so they can be assigned predefined pseudo-colors during the digital imaging and visualization process. The present study demonstrates how MCB patterns can be produced by region-specific microdissection derived (mcd) libraries as well as collections of yeast or bacterial artificial chromosomes (YACs and BACs, respectively). We compared the efficiency of an mcd library based approach with the hybridization of collections of locus-specific probes (LSP) for fluorescent banding of three rather differently sized human chromosomes, i.e., chromosomes 2, 13, and 22. The LSP sets were comprised of 107 probes specific for chromosome 2, 82 probes for chromosome 13, and 31 probes for chromosome 22. The results demonstrated a more homogeneous coverage of chromosomes and thus, more desirable banding patterns using the microdissection library-based MCB. This may be related to the observation that chromosomes are difficult to cover completely with YAC and/or BAC clones as single-color fluorescence in situ hybridization (FISH) experiments showed. Mcd libraries, on the other hand, provide high complexity probes that work well as region-specific paints, but do not readily allow positioning of breakpoints on genetic or physical maps as required for the positional cloning of genes. Thus, combinations of mcd libraries and locus-specific large insert DNA probes appear to be the most efficient tools for high-resolution cytogenetic analyses.

Chromosome Banding↗
PubMed2002

Demystifying chromosome preparation and the implications for the concept of chromosome condensation during mitosis.

The processes taking place during routine chromosome preparation are not well understood. In this study, the morphological changes in amniotic fluid cells, blood lymphocytes, and bone marrow cells in the metaphase stage were examined under an inverted microscope during chromosome preparation. The putative processes that occur during chromosome preparation were simulated in suspension, and the cells were treated with different mixtures of hypotonic solution, fixative, methanol, acetic acid, and water. Evaporation of the fixative was performed under normal atmospheric conditions and under vacuum at different levels of humidity. Freeze fracture electron microscopy was used to analyze the effects of fixative on the cell membrane. Confocal microscopic analysis was used to investigate three-dimensionally the effects of hypotonic treatment on the positions of chromosomes in fixed mitotic lymphocytes. Chromosome preparation-induced changes in the lengths of single chromosomes were also investigated. The results show that chromosome spreading involves significant water-induced swelling of mitotic cells during evaporation of the fixative from the slide, which is a prerequisite for chromosomal elongation, the production of metaphase spreads for chromosome analysis, and the appearance of Giemsa banding patterns. Hypotonic treatment is essential for well-spread metaphase chromosomes because it moves the chromosomes from a central to a more peripheral position in the cell, where they can be stretched more effectively during mitotic swelling. Like mitotic cells, isolated single chromosomes also have their own potential to swell and lengthen during chromosome preparation. We hypothesize that chromosome preparation leads to a genome-wide chromosomal region-specific opening of chromatin structures as GTG-light bands and sub-bands. Living cells may possess a similar mechanism, which is used only to open single chromatin structures to facilitate transcription. We propose the concept of chromosomal region-specific protein swelling.

Cells, Cultured↗
PubMed2001

Mosaic chromosomal aberrations in synovial fibroblasts of patients with rheumatoid arthritis, osteoarthritis, and other inflammatory joint diseases.

Chromosomal aberrations were comparatively assessed in nuclei extracted from synovial tissue, primary-culture (P-0) synovial cells, and early-passage synovial fibroblasts (SFB; 98% enrichment; P-1, P-4 [passage 1, passage 4]) from patients with rheumatoid arthritis (RA; n = 21), osteoarthritis (OA; n = 24), and other rheumatic diseases. Peripheral blood lymphocytes (PBL) and skin fibroblasts (FB) (P-1, P-4) from the same patients, as well as SFB from normal joints and patients with joint trauma (JT) (n = 4), were used as controls. Analyses proceeded by standard GTG-banding and interphase centromere fluorescence in situ hybridization. Structural chromosomal aberrations were observed in SFB (P-1 or P-4) from 4 of 21 RA patients (19%), with involvement of chromosome 1 [e.g. del(1)(q12)] in 3 of 4 cases. In 10 of the 21 RA cases (48%), polysomy 7 was observed in P-1 SFB. In addition, aneusomies of chromosomes 4, 6, 8, 9, 12, 18, and Y were present. The percentage of polysomies was increased in P-4. Similar chromosomal aberrations were detected in SFB of OA and spondylarthropathy patients. No aberrations were detected in i) PBL or skin FB from the same patients (except for one OA patient with a karyotype 45,X[10]/46,XX[17] in PBL and variable polysomies in long-term culture skin FB); or ii) synovial tissue and/or P-1 SFB of normal joints or of patients with joint trauma. In conclusion, qualitatively comparable chromosomal aberrations were observed in synovial tissue and early-passage SFB of patients with RA, OA, and other inflammatory joint diseases. Thus, although of possible functional relevance for the pathologic role of SFB in RA, these alterations probably reflect a common response to chronic inflammatory stress in rheumatic diseases.

Arthritis, Psoriatic↗
PubMed2001

Mass spectrometry meets chip technology: a new proteomic tool in cancer research?

DNA chip technologies are the most exiting genomic tools, which were developed within the last few years. It is, however, evident that knowledge of the gene sequence or the quantity of gene expression is not sufficient to predict the biological nature and function of a protein. This can be particularly important in cancer research where post-translational modifications of a protein can specifically contribute to the disease. To address this problem, several proteomic tools have been developed. Currently the most widely used proteomic tool is two-dimensional protein gel electrophoresis (2-DE), which can display protein expression patterns to a high degree of resolution. As an alternative to 2-DE, a preliminary study using a new technique was employed to generate protein expression patterns from whole tissue extracts. Surface-enhanced laser desorption/ionization (SELDI) allows the retention of proteins on a solid-phase chromatographic surface (ProteinChip Array) with direct detection of retained proteins by time of flight-mass spectrometry (TOF-MS). Using this system, we analyzed eight cases of renal cell carcinoma (RCC) including normal, peripheral and central tumor tissue as well as four microdissected cases of cervical intraepithelial neoplasia (CIN) and three microdissected cases of cervix uteri carcinoma. Differentially expressed proteins were found by comparing the protein expression patterns generated using SELDI-based TOF-MS of tumor tissue with normal and neoplastic tissue, respectively. By applying this fast and powerful ProteinChip array technology it becomes possible to investigate complex changes at the protein level in cancer associated with tumor development and progression.

Carcinoma, Renal Cell↗
PubMed2001

Genetic imbalances in 26 cases of penile squamous cell carcinoma.

To obtain more information on chromosomal changes in the up-to-now poorly studied tumor class of penile squamous cell carcinoma (SCC), we performed a comparative genomic hybridization study of 26 cases of this rare tumor. DNA sequence copy number alterations (CNAs) very similar to those detected in other SCC types, such as oral and esophageal SCC, were noted. The most common copy number gains were found in 8q24, 16p11-12, 20q11-13, 22q, 19q13, and 5p15, and the most common deletions were detected in 13q21-22, 4q21-32, and along the X chromosome. Classifying the patients according to the number of CNAs showed a possible correlation with clinical outcome.

Adult↗
PubMed2001

Maternal UPD 20 in an infant from a pregnancy with mosaic trisomy 20.

Maternal uniparental disomy (UPD) 20 was found in a 35-month-old girl, the product of a pregnancy complicated by a prenatal diagnosis of mosaic trisomy 20. Phenotypic abnormalities included pre- and postnatal growth failure, microcephaly, minor dysmorphic features and psychomotor developmental delay. Chromosomal analysis on cord blood revealed only a normal 46,XX karyotype. Microsatellite analysis of 27 chromosome 20 loci confirmed maternal UPD for all 11 informative markers. Maternal heterodisomy was detected in two and maternal isodisomy in three loci. In the remaining six loci, a non-informative maternal UPD pattern was displayed, as mother and proband are homozygous for the same allele. To our knowledge this is the first reported case of maternal disomy 20 with normal karyotype ascertained by a mosaic trisomy 20 pregnancy.

Adult↗
PubMed2001

Maternal insertion of 18q11.2-q12.2 in 18p11.3 of the same chromosome analysed by microdissection and multicolour banding (MCB).

OBJECTIVES: Different aberrations in one chromosome 18 were prenatally detected during each of three different pregnancies of a healthy woman. Routine cytogenetic analysis revealed a morphologically altered maternal chromosome 18 as well. The purpose of the current study was to characterize these cytogenetic changes in detail and thus to clarify the reason for the recurrent appearance of morphologically altered chromosomes 18 in this family. METHODS: As GTG banding did not allow resolution of the kind of aberrations present in these four cases, the following molecular cytogenetic approaches were used: microdissection combined with reverse painting and multicolour banding (MCB) analysis using a chromosome 18 specific probe set. RESULTS: Molecular cytogenetic approaches revealed that fetus 1 had a derivative chromosome del(18)(q11.2q12.2), fetus 2 and the mother had the identical derivative chromosomes ins(18)(pterp11.32::q12.2q11.2::p11.32q11.2::q12.3qter) and fetus 3 had a dup(11.2q12.2). CONCLUSION: Partial monosomy in fetus 1 and partial trisomy in fetus 3 can be explained by crossing over events during maternal meiosis.

Adult↗
PubMed2001

A new multicolor-FISH approach for the characterization of marker chromosomes: centromere-specific multicolor-FISH (cenM-FISH).

Centromere-specific multi-color FISH (cenM-FISH) is a new multicolor FISH technique that allows the simultaneous characterization of all human centromeres by using labeled centromeric satellite DNA as probes. This approach allows the rapid identification of all human centromeres by their individual pseudo-coloring in one single step and is therefore a powerful tool in molecular cytogenetics. CenM-FISH fills a gap in multicolor karyotyping using WCP probes and distinguishes all centromeric regions apart from the evolutionary highly conserved regions on the chromosomes 13 and 21. The usefulness of the cenM-FISH technique for the characterization of small supernumerary marker chromosomes with no (or nearly no) euchromatin and restricted amounts of available sample material is demonstrated in prenatal, postnatal, and tumor cytogenetic cases. In addition, rarely described markers with the involvement of heterochromatic material inserted into homogeneously staining regions could be identified and characterized by using the cenM-FISH technique.

Centromere↗
PubMed2001

Improved definition of chromosomal breakpoints using high-resolution multicolour banding.

Characterisation of chromosome rearrangements using conventional banding techniques often fails to determine the localisation of breakpoints precisely. In order to improve the definition of chromosomal breakpoints, the high-resolution multicolour banding (MCB) technique was applied to identify human chromosome 5 breakpoints from 40 clinical cases previously assessed by conventional banding techniques. In 30 cases (75%), at least one breakpoint was redefined, indicating that MCB markedly improves chromosomal breakpoint localisation. The MCB pattern is highly reproducible and, in contrast to conventional banding pattern, is consistent in both short and elongated chromosomes. This might be of fundamental interest for the detection of chromosomal abnormalities, especially in tumour cells. Moreover, MCB even allows the detection of abnormalities that remain cryptic in GTG-banding analysis.

Chromosome Aberrations↗
PubMed2001

Brachytelephalangic dwarfism due to the loss of ARSE and SHOX genes resulting from an X;Y translocation.

Here we report an 8-year-old male patient who had mesomelic shortening of forearms and legs, brachytelephalangia and ichthyotic skin lesions. Chromosomal analysis showed an X;Y translocation involving the short arm of the X chromosome (Xp). Fluorescence in situ hybridization (FISH) and molecular studies localized the breakpoints on Xp22.3 in the immediate vicinity of the KAL gene demonstrating deletions of steroid sulfatase (STS), arylsulfatase E (ARSE), and short stature homeo box (SHOX) genes. It was suspected that the patient was suffering from chondrodysplasia punctata because of a loss of the arylsulfatase E (ARSE) gene. However, no stippled epiphyses were to be seen in the neonatal radiograph. Interestingly, this patient is the first case with a proven loss of the ARSE gene without chondrodysplasia punctata, assuming that chondrodysplasia punctata is not an obligatory sign of ARSE gene loss. Brachytelephalangia was the only result of ARSE gene deletion in this case. The patient's mother also had dwarfism and showed Madelung deformity of the forearms. She was detected as a carrier of the same aberrant X chromosome. The male patient did not show Madelung deformity, demonstrating that Lerri-Weill syndrome phenotype may be still incomplete in children with SHOX gene deletion. The wide clinical spectrum in the male and the Leri-Weill phenotype in his mother are the results of both a deletion involving several sulfatase genes in Xp22.3 and the SHOX gene located in the pseudoautosomal region. Nevertheless, there is no explanation for the absence of chondrodysplasia punctata despite the total loss of the ARSE gene. Further studies are necessary to investigate genotype/phenotype correlation in cases with translocations or microdeletions on Xp22.3, including the ARSE and the SHOX gene loci.

Arylsulfatases↗
PubMed2001

Molecular cytogenetic characterization of an acquired minute supernumerary marker chromosome as the sole abnormality in a case clinically diagnosed as atypical Philadelphia-negative chronic myelogenous leukaemia.

A case of chronic myelogenous leukaemia (CML) in a 48-year-old man is reported. To the best of our knowledge, this is the first report of a Philadelphia-negative CML with an acquired small supernumerary marker chromosome (SMC) 11 as the sole abnormality. The derivative chromosome 11 was studied in detail using molecular cytogenetic methods; fluorescence in situ hybridization (FISH) using centromere- and region-specific probes for chromosome 11, microdissection, micro-comparative genomic hybridization (micro-CGH) and the recently developed multicolour banding (MCB) technique. The acquired SMC was determined to be a ring chromosome that can be described as r(11)(:p11.2-->q13.1:q14:).

Chromosome Aberrations↗