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Uwe Claussen

Publications and source records attributed to Uwe Claussen.

At least 55 records · Page 3Linked to original sources
PubMed2003

Detailed Hylobates lar karyotype defined by 25-color FISH and multicolor banding.

A comprehensive and detailed comparative chromosome map of the white-handed gibbon (Hylobates lar = HLA) has been established by hybridizing the recently developed complete human multicolor banding (MCB) probe set on metaphase chromosomes of a male HLA lymphoblastoid cell line. Thus, it was possible to precisely determine the breakpoints and distribution plus orientation of specific DNA-regions in this cytogenetically highly rearranged species compared to Homo sapiens (HSA). In general, the obtained results are in concordance with previous molecular-cytogenetic studies. In this study all 71 breakpoints present in HLA compared to HSA could be determined exactly. This study is a valuable complement to our knowledge on the phylogeny of huminoid chromosomes.

Animals↗
PubMed2002

The DNA-based structure of human chromosome 5 in interphase.

In contrast to those of metaphase chromosomes, the shape, length, and architecture of human interphase chromosomes are not well understood. This is mainly due to technical problems in the visualization of interphase chromosomes in total and of their substructures. We analyzed the structure of chromosomes in interphase nuclei through use of high-resolution multicolor banding (MCB), which paints the total shape of chromosomes and creates a DNA-mediated, chromosome-region-specific, pseudocolored banding pattern at high resolution. A microdissection-derived human chromosome 5-specific MCB probe mixture was hybridized to human lymphocyte interphase nuclei harvested for routine chromosome analysis, as well as to interphase nuclei from HeLa cells arrested at different phases of the cell cycle. The length of the axis of interphase chromosome 5 was determined, and the shape and MCB pattern were compared with those of metaphase chromosomes. We show that, in lymphocytes, the length of the axis of interphase chromosome 5 is comparable to that of a metaphase chromosome at 600-band resolution. Consequently, the concept of chromosome condensation during mitosis has to be reassessed. In addition, chromosome 5 in interphase is not as straight as metaphase chromosomes, being bent and/or folded. The shape and banding pattern of interphase chromosome 5 of lymphocytes and HeLa cells are similar to those of the corresponding metaphase chromosomes at all stages of the cell cycle. The MCB pattern also allows the detection and characterization of chromosome aberrations. This may be of fundamental importance in establishing chromosome analyses in nondividing cells.

Cell Cycle↗
PubMed2002

Heterogenic molecular basis for loss of ABL1-BCR transcription: deletions in der(9)t(9;22) and variants of standard t(9;22) in BCR-ABL1-positive chronic myeloid leukemia.

The objective of this study was to characterize the ABL1-BCR fusion gene in 76 BCR-ABL1-positive chronic myeloid leukemia (CML) patients regarding expression as well as genomic status, to assess the frequency of ABL1-BCR gene deletion in these patients, which has been reported to be an adverse prognostic factor in Philadelphia chromosome-positive CML. Patients were analyzed for ABL1-BCR 1b-b3 and/or 1b-b4 transcription by RT-PCR analysis. ABL1-BCR gene status was analyzed by FISH in 16 CML patients with no ABL1-BCR transcript. FISH revealed a partial or total deletion of the ABL1-BCR gene in 9/16 and localized the 5' portion of ABL1 and the 3' portion of BCR at separated loci in 5/16 patients. The latter FISH pattern resulted from a nonreciprocal translocation in two and a complex translocation in three individuals. In 2/16 patients, FISH could not exclude an intact ABL1-BCR fusion gene. Thus, most CML patients without ABL1-BCR transcript could be characterized cytogenetically to belong to two major subgroups: a silent ABL1-BCR gene was attributed to a deletion in der(9)t(9;22) in 56% of the investigated patients or to variants of a standard t(9;22) (approximately 31%). Conversely, none of the 50 patients with an ABL1-BCR transcript exhibited a variant t(9;22) in GTG-banding analysis. Thus, genomic aberrations such as deletions or complex genomic rearrangements are the basic and most frequent cause for ABL1-BCR RNA negativity in CML. The heterogeneity of the underlying molecular mechanisms may explain divergent clinical implications described for patients with an ABL1-BCR deletion and those with no ABL1-BCR transcript.

Chromosome Deletion↗
PubMed2002

Is 24-color FISH detection of in-vitro radiation-induced chromosomal aberrations suited to determine individual intrinsic radiosensitivity?

BACKGROUND: Reliable determination of intrinsic radiosensitivity in individual patients is a serious need in radiation oncology. Chromosomal aberrations are sensitive indicators of a previous exposure to ionizing irradiation. Former molecular cytogenetic studies showed that such aberrations as an equivalent of intrinsic radiosensitivity can be detected by fluorescence in-situ hybridization (FISH) techniques using whole chromosome painting (wcp) probes. However, only one up to three randomly chosen wcp probes have been applied for such approaches until now. As a random distribution of chromosomal rearrangements along the chromosomes is up to now still controversial, the power of the 24-color FISH approach should be elucidated in the present study. METHODS AND MATERIAL: Lymphocytes derived from lymphoblastoid cell lines of one patient with Nijmegen breakage syndrome (NBS homozygote) and of two NBS heterozygotes and peripheral blood lymphocytes of two controls were analyzed. Samples of each patient/control were irradiated in vitro with 0.0 Gy, 0.7 Gy or 2.0 Gy prior to cultivation. Chromosomal aberrations were analyzed in detail and quantified by means of 24-color FISH as an expression of the individual intrinsic radiosensitivity. RESULTS: 24-color FISH analyses were done in a total of 1,674 metaphases. After in-vitro irradiation, 21% (0.7 Gy) or 57% (2.0 Gy) of the controls' cells, 15% (0.7 Gy) or 53% (2.0 Gy) of the heterozygotes' cells and 54% (0.7 Gy) or 79% (2.0 Gy) of the homozygote's cells contained aberrations. The highest average rates of breaks per mitosis [B/M] (0.7 Gy: 1.80 B/M, 2.0 Gy: 4.03 B/M) and complex chromosomal rearrangements [CCR] (0.7 Gy: 0.20 CCR/M, 2.0 Gy: 0.47 CCR/M) were observed in the NBS patient. Moreover, the proportion of different aberration types after irradiation showed a distinct increase in the rate of CCR combined with a decrease in dicentrics in the NBS homozygote. CONCLUSION: To come to a more complete picture of radiation-induced aberrations and to detect and quantify genetically determined intrinsic radiosensitivity, a 24-color FISH approach using all human chromosome painting probes has been successfully applied on cytogenetic preparation lymphocytes. The controls and NBS heterozygotes were clearly distinguished from the NBS homozygote subject.

Adult↗
PubMed2002

Homologous sequences at human chromosome 9 bands p12 and q13-21.1 are involved in different patterns of pericentric rearrangements.

A thorough study of the heterochromatin organisation in the pericentromeric region and the proximal long (q) and short (p) arms of human chromosome 9 (HSA 9) revealed homology between 9p12 and 9q13-21.1, two regions that are usually not distinguishable by molecular cytogenetic techniques. Furthermore, the chromosomal regions 9p12 and 9q13-21.1 showed some level of homology with the short arms of the human acrocentric chromosomes. We studied five normal controls and 51 clinical cases: 48 with chromosome 9 heteromorphisms, one with an exceptionally large inversion and two with an additional derivative chromosome 9. Using fluorescence in situ hybridisation (FISH) with three differentially labelled chromosome 9-specific probes we were able to distinguish 12 heteromorphic patterns in addition to the most frequent pattern (defined as normal). In addition, we studied one inversion 9 case with the recently described multicolour banding (MCB) technique. Our results, and previously published findings, suggest several hotspots for recombination in the pericentromeric heterochromatin of HSA 9. They also demonstrate that constitutional inversions affecting the pericentromeric region of chromosome 9 carry breakpoints located preferentially in 9p12 or 9q13-21.1 and less frequently in 9q12.

Chromosome Aberrations↗
PubMed2002

Suspension (S)-FISH, a new technique for interphase nuclei.

We describe a versatile method for performing fluorescence in situ hybridization (FISH) in suspension instead of on a slide as usually done. This so-called suspension-FISH (S-FISH) opens new possibilities for the analysis of shape and functions of the human interphase nucleus. The procedure is described and the first results using this approach are presented.

Cell Nucleus↗
PubMed2002

FISH banding methods: applications in research and diagnostics.

Recently, several chromosome banding techniques based on fluorescence in situ hybridization (FISH) have been developed for the human and the mouse genome. In contrast to the standard chromosome banding techniques presently used, giving a protein-related banding pattern, those FISH techniques are DNA-specific. Currently the FISH banding methods are still under development and no high resolution banding technique is available that can be used for a whole genome in one hybridization. Nevertheless, FISH banding methods were used successfully for research in evolution- and radiation-biology, as well as for studies on the nuclear architecture. Moreover, their suitability for diagnostic purposes has been proven in prenatal, postnatal and tumor cytogenetics, indicating that they are an important tool with the potential to partly replace the conventional banding techniques in future.

Animals↗
PubMed2002

Current developments in human molecular cytogenetic techniques.

In the last decade a variety of fluorescence in situ hybridization (FISH) assays have been developed. In this paper we present an overview on the currently available methods in molecular cytogenetics, highlighting their advantages and limitations, as well as their applications. Even though one has to be impressed by the total number of new techniques introduced in molecular cytogenetics, one has to be aware of the fact that it is not the brilliance of a technique that is important but the scientific question that can be addressed by it. In this review special emphasis has given in describing possible strategies for the characterization of marker and derivative chromosomes in tumor- and clinical cytogenetics.

Centromere↗
PubMed2002

TP53 alterations as a potential diagnostic marker in superficial bladder carcinoma and in patients serum, plasma and urine samples.

Molecular markers are needed for better distinguishing of non-invasive papillary (pTa) and minimally invasive (pT1) bladder carcinomas and for identifying individual tumors with a high risk of recurrence or disease progression. First aim of our study was to evaluate TP53 microsatellite and mutation analysis as an effective concept for the characterization of superficial bladder tumors with different biological aggressiveness. Mutation screening in the TP53 hot spot region was performed in 55 microdissected superficial bladder tumor samples by direct genomic sequencing. PCR based LOH analysis was done with two markers at 17p13. Second, there is considerable interest in the development of non-invasive techniques that would detect recurrent bladder neoplasia. In order to evaluate TP53 alterations as a potential marker for a non-invasive diagnosis of recurrences or residuals and to determine whether tumor-specific DNA exhibiting LOH or sequences harbouring a mutation, can be detected in body fluids, mutation screening was performed in urine, plasma and serum of patients with a mutated primary tumor. LOH analysis with two markers at 17p was done in the corresponding urine and blood samples of 31 primary tumors. As seen from our results, TP53 inactivation by mutation seems to characterize higher malignant superficial bladder tumors which tend to recur and in which the probability is higher that the rezidives progress to muscle invasive growth pattern. Only in 2/8 cases, the TP53 mutation from the primary tumor could be re-detected in patients urine and blood. 17p microsatellite changes with at least one marker were found in 30/31 body fluids of the tumor patients (97%). Correlating the 17p status found in body fluids to the status of the primary tumor, the concordance is only about 52%. We conclude that TP53 genotyping as a non-invasive diagnostic tool in outpatient samples is of limited value for clinical practice.

Aged↗
PubMed2002

Telomerase activity in microdissected human breast cancer tissues: association with p53, p21 and outcome.

To evaluate the invasive potential of early tumorous lesions of the breast, especially DCIS, we have analyzed semiquantitative telomerase activity in well defined microdissected tissue areas from malignant or benign breast lesions from 145 patients. In order to prove the relationship to cell cycle defects, p53 and p21 proteins were analyzed in corresponding cryostat sections by immunohistochemistry. Telomerase activity was detected in 3 (33.3%) out of 9 benign breast lesions and 109 (80.1%) of 136 malignant tumors. Our study failed to demonstrate an association between telomerase activity, p21, established prognostic factors, such as lymph node status and metastasis, and clinical outcome. We found a high rate of cases (42.2%) with intratumoral heterogeneity concerning telomerase activity status. Telomerase heterogeneity was more obvious in samples with mixed tissue types, although we could not assign specifically the telomerase activity to lobular, ductal and intraductal tissue areas. Telomerase activity was detected in 81.8% of ductal carcinoma in situ (DCIS) which indicates telomerase reactivation as an early event in carcinogenesis. Fifteen (19.5%) out of 77 cases were positive for p53 protein in immunohistochemistry and found to be significantly more frequent in the subgroup with poor outcome. There was only a trend to an association of p53 with high level of telomerase. The prognostic relevance of telomerase activity for patients with benign breast lesions must be further investigated.

Adult↗
PubMed2002

Microdissection based high resolution multicolor banding for all 24 human chromosomes.

The multicolor-banding (MCB) approach allows the differentiation of chromosome region specific areas at the band and sub-band level and is based on region-specific microdissection libraries producing changing fluorescence intensity ratios along the chromosomes. The latter are used to assign different pseudocolors to specific chromosomal regions. We present the complete set of 138 region-specific microdissection libraries for the entire human genome and the resulting MCB patterns for all human chromosomes at the 450-550 band level. In the present work, the creation and handling of the microdissection libraries is detailed for the first time. Additionally, the unique possibilities of the MCB technique to adjust the pseudocolor bands according to the necessities of the studied case is presented in exemplarity. In conclusion, the MCB-technique is a high resolution alternative to other FISH based chromosome banding approaches and suited to clarify, which changes appeared in complex chromosomal rearrangements.

Chromosome Banding↗
PubMed2002

Molecular characterization of head and neck tumors by analysis of telomerase activity and a panel of microsatellite markers.

Head and neck cancer is a frequent malignancy with a complex, and up to now not clear etiology. The reactivation of telomerase activity and losses or gains of specific chromosomal regions, which point to deletions of tumor suppressor genes or amplification of oncogenes are supposed to be the molecular processes during the development and progression of head and neck cancer. Therefore, we analyzed telomerase activity and microsatellite markers using a genome wide panel of 28 microsatellite markers in 38 head and neck squamous-cell carcinomas (HNSCC). Our microsatellite marker set included distinct chromosomal areas that all likely harbor genes contributing to the carcinogenesis of HNSCC. DNA or protein lysates were obtained from primary tumors and compared to peripheral lymphocytes or corresponding normal tissue. At least one genomic alteration [loss of heterozygosity (LOH), or microsatellite instability (MSI)] was found in 31 of the 38 cases (82%). Most frequently we detected an LOH in the chromosomal region 9p12-21 where at least the tumor suppressor genes (TSG) p16INK4A, p14ARF and p15INKB are localized. The comparison between grade two and grade three tumors showed a highly changed frequency of LOH in the chromosomal region 7q31, where a putative TSG is predicted. Telomerase activity was present in 31/37 (83.8%) tumor samples independent of the histopathological staging and grading of the tumors. These molecular characterizations of HNSCC may be a further hint for the involvement of additional, so far unknown, TSGs in the tumor progression and will elucidate the regulation of telomerase.

Carcinoma, Squamous Cell↗
PubMed2002

A complex translocation event between the two homologues of chromosomes 5 leading to a del(5)(q21q33) as a sole aberration in a case clinically diagnosed as CML: characterization of the aberration by multicolor banding.

We report on a patient with a clinically diagnosed Philadelphia negative chronic myelogenous leukemia (CML) with a so far unrecorded complex translocation event between the two homologue chromosomes 5. At the GTG-band level the karyotype was normal, apart from an enlarged chromosome 5 and an extremely shortened second chromosome 5. Both derivative chromosomes 5 consisted exclusively of #5 derived material as proven by 24-color FISH. To characterize the complex aberration in more detail the multicolor banding (MCB) technique using a chromosome 5 specific probe set was applied. Using this DNA-based high resolution banding procedure, the karyotype could be described as 46,XX,del(5)(pterright curved arrow q12::q33right curved arrow qter),ins(5)(pterright curved arrow q15::q12right curved arrow q21::q21right curved arrow qter). In consequence, the aberration leads to a partial deletion of the long arm of chromosome 5: del(5)(q21q33), which would not have been identified using conventional banding techniques or 24-color FISH.

Aged↗
PubMed2002

Cultivation of fetal erythroid precursors from maternal blood: isolation and characterization by PCR and FISH.

Cultivation of fetal progenitor cells from maternal blood offers the opportunity to produce sufficient fetal cells for prenatal molecular genetic and cytogenetic analysis. For in vitro cultivation, 10 ml of blood was collected from 22 women carrying a male fetus. After triple-density gradient centrifugation, the mononucleated cells were cultivated for 10 to 14 days in special hematopoietic growth medium. Red and white colored cell colonies were individually collected by micromanipulation. A representative sample from each colony was characterized by chromosome Y-specific polymerase chain reaction (PCR) systems. The remaining cells of the Y-positive colonies were used to perform chromosome preparations and fluorescence in situ hybridization (FISH) to detect XY-positive interphase nuclei and metaphases. Y-positive signals could be detected in 15 (68%) of the 22 analyzed blood samples. With SRY PCR 10.5% (40/379) of the collected red colonies were determined to be of fetal origin and 6.1% (32/522) of the colonies analyzed by amelogenin PCR were Y-positive. All collected white cell colonies were Y-negative. FISH analyses of PCR-positive colonies revealed that less than 30% of the cells within a colony are of fetal origin and reflect more precisely the actual situation within a single colony. Moreover the successful preparation of fetal metaphases in non-invasive prenatal diagnosis is presented.

Chromosomes, Human, Y↗
PubMedDate not supplied

Characterization of pepsinogen C as a potential biomarker for gastric cancer using a histo-proteomic approach.

We analyzed 74 cryostat sections of central gastric tumor, tumor margin, and normal gastric epithelium using ProteinChip Arrays and SELDI-TOF MS. One peak was significantly down-regulated in tumor tissue (P = 1.43 x 10(-6)) and identified as pepsinogen C using MS/MS analysis and immunodepletion. This signal was further characterized by immunohistochemistry. This work demonstrates that differentially expressed signals can be identified and assessed using a proteomic approach comprising tissue-microdissection, protein profiling, and immunohistochemistry.

Biomarkers↗
PubMedDate not supplied

First case of trisomy 13 plus mosaic trisomy 1q.

OBJECTIVES: In a case with severe sonographic abnormalities followed by missed abortion in week 14 + 5 days, cytogenetic analysis was performed on placental tissue. A mosaic karyotype 47,XY,+13,add(1)(q44)[3]/47,XY, +13[9]/46,XY[36] was detected. The purpose of the present study was to characterize the additional material on chromosome 1q. METHODS: According to GTG banding, the additional material on chromosome 1 was most probably chromosome 1 material. Thus, multicolor banding analysis using a chromosome 1 specific probe set was done to precisely describe the rearranged chromosome 1. RESULTS: Molecular cytogenetic approaches revealed that the derivative chromosome 1 was der(1)(1p36.3-->1q44::1q12-->1q44). CONCLUSIONS: This is the first description of a case with a trisomy 13 plus a partial trisomy 1q presenting with clinical signs of both aberrations. Moreover, the multicolor banding technique is suited to resolve complex karyotypes in the prenatal diagnosis, i.e., chromosome preparations of fibroblasts.

Abortion, Missed↗