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U Bockmühl

Publications and source records attributed to U Bockmühl.

At least 37 records · Page 2Linked to original sources
PubMed2001

High-resolution petrous bone imaging using multi-slice computerized tomography.

Multi-slice computerized tomography (MSCT) is considered to provide superior image quality. We defined a data acquisition protocol for high-resolution (HR) temporal bone imaging using MSCT and assessed its impact on data acquisition and post-processing (PP). The data acquisition protocol was defined in cadaveric phantom studies performed by MSCT and subsequently applied to 38 patients referred for temporal bone assessment. The parameters image quality and diagnostic value of MSCT data were assessed for the cross-sectional source images as well as for 2-dimensional (2D) reformations and 3-dimensional (3D) reconstructions by 3 radiologists by comparison with incremental HR scans of 17 patients with suspected middle ear disorders. The data acquisition protocol yielded HR images with an excellent detail resolution and a comparable image quality of cross-sectional scans and related orthogonal reformations. MSCT achieved higher scores for image quality and diagnostic value (p < 0.001, t-test) than incremental HR CT with regard to both 2D and 3D reconstructions. MSCT improves the image quality of HR cross-sectional scans as well as that of 2D and 3D PP techniques in petrous bone imaging. The radiation exposure of the eye lenses is increased by MSCT as gantry angulation is not yet possible in the helical scan mode.

Algorithms↗
PubMed2001

Visualization of inner ear dysplasias in patients with sensorineural hearing loss.

PURPOSE: We evaluated a data acquisition and post-processing protocol for inner ear (IE) assessment by MR imaging in patients, suffering from various labyrinth malformations. MATERIAL AND METHODS: MR IE studies of 158 consecutive patients (316 IEs) suffering from sensorineural hearing loss without evidence of an acoustic neurinoma were reviewed for pathologies of the IE and internal acoustic meatus. High-resolution MR data of all abnormal IE studies (n=45) were post-processed to previously standardized 3D volume rendered (VR) reconstructions. RESULTS: In 9 patients (5.7%) the following IE dysplasias were detected: malformation of the cochlea (6 IEs), vestibulum (4 IEs), semicircular canals (12 IEs) and vestibular aqueduct/endolymphatic sac (10 IEs). One patient showed evidence of an aplasia of the vestibulocochlear nerve. In 4 patients multiple IE dysplasias were encountered. Comprehensive 3D visualization of all labyrinthine dysplasias was achieved by the use of two VR reconstructions. The overall time for bilateral IE assessment amounted to 30-35 min. CONCLUSION: The imaging protocol allows for rapid and comprehensive visualization of various IE dysplasias, based on a limited number of VR reconstructions.

Adolescent↗
PubMed2000

Analysis of the DMBT1 gene in carcinomas of the respiratory tract.

Loss of chromosome 10q is a critical step during the progression and metastasis formation of lung cancer. We recently defined 3 distinct regions of allelic imbalances and considered the DMBT1 gene at 10q25-q26 an interesting candidate for the most telomeric region. Therefore, we investigated DMBT1 in 25 cancer cell lines and 39 primary tumors of the respiratory tract. The analysis by RT-PCR and Northern blot hybridization revealed that the gene is expressed in all tumors and cell lines and diminished in the SCLC line H187, indicating that RT-PCR is critical when used as the single method for the evaluation of gene expression. No mutations were found by SSCP analysis of the cDNA and the partially known genomic sequence. Similarly, Southern blot hybridization was unable to detect homozygous deletions. Allelotyping of the markers D10S587, D10S1708 and D10S1723 located near or within the DMBT1 gene did not reach the peak incidence of the 3 minimally deleted regions that we recently defined. In summary, our data do not confirm previous findings reporting frequent loss of DMBT1 expression in lung cancer. However, they strengthen the notion that the responsible gene on chromosome 10q25-q26 mediating tumor progression and metastasis formation in respiratory tract cancer remains enigmatic.

Agglutinins↗
PubMed2000

[Improved prognostic assessment of head-neck carcinomas by new genetic markers].

In individual patients with head and neck squamous cell carcinomas (HNSCC), established prognostic factors do not satisfactorily predict clinical outcome. For the first time we investigated a total of 100 HNSCC by Comparative Genomic Hybridization (CGH) to define chromosomal alterations that are associated with the patients prognosis. Patients were followed for at latest 4 but at least 2 years after surgery or until death. During this observation period twenty-nine of them died because of cancer disease. The Kaplan-Meier method was used plotting survival curves for every single chromosomal alteration as well as every clinico-pathological parameter. The curves were tested for significance by the log rank as well as the Breslow test. Significance of particular prognostic parameters was then evaluated by the Cox regression model. The overall survival time as well as the recurrence free survival time were significantly lower in patients who's tumors showed amplifications of the chromosomal region 11q13 (p = 0.0008 for LR and p = 0.0024 for B). The survival time of the patients was also lower if the carcinomas carried over-representations of chromosome 3q (p = 0.0299 for LR and p = 0.0546 for B). Multivariate analysis (Cox's proportional hazards model) revealed both alterations as most important independent prognostic factors in HNSCC. None of the conventional clinicopathological parameters (pT-, pN-status, UICC stage, grading) achieved statistical significance in the multivariate model. These results suggest that in HNSCC the occurrence of 11q13 amplification and 3q overrepresentation are highly significant independent prognostic markers and of better value than the established TNM and grading criteria.

Biomarkers, Tumor↗
PubMed2000

[Squamous epithelial carcinoma in a duct cyst of the submandibular gland].

Squamous cell carcinomas are rare malignant tumors of the major and minor salivary glands in the head region. This is the report of a squamous cell carcinoma within a cyst of the submandibular gland. Clinical, histological and immunohistochemical findings are presented, and the importance as well as the therapeutic strategy of this very rare malignant tumor of the salivary glands are discussed.

Aged↗
PubMed2000

Genetic imbalances with impact on survival in head and neck cancer patients.

Chromosomal imbalances in 113 primary head and neck squamous cell carcinomas (HNSCCs) determined by comparative genomic hybridization were correlated with patients survival using custom-made computer software which enabled the assessment of individual chromosomal loci. The Kaplan-Meier analysis revealed that overrepresentations of 2q12, 3q21-29, 6p21.1, 11q13, 14q23, 14q24, 14q31, 14q32, 15q24, 16q22, and deletions of 8p21-22 and 18q11.2 were significantly associated with both shorter disease-free interval and disease-specific survival in this tumor collective. Multivariate Cox proportional hazards regression models consistently identified the gains of 3q21-29, 11q13, and the loss of 8p21-22 as independent prognostic markers carrying a higher significance than the nodal status as the only clinicopathological parameter with statistical importance. In addition, these three markers allowed a molecular dissection of the patients with low clinical risk (pN0 and pT2 tumors). Thus, the genomic data being derived from the evaluation of primary HNSCC enabled a stratification of the patients into subgroups with different survival highlighting the necessity of a genetically based tumor classification for refining diagnosis and treatment of HNSCC patients.

Chromosome Aberrations↗
PubMed2000

[Deletion of chromosome 10q--a marker for metastasis of head-neck carcinomas?].

BACKGROUND: Comparative genomic hybridization (CGH) was applied to squamous cell carcinomas of the head and neck to define genetic alterations that are associated with the metastatic phenotype. METHODS: CGH is a molecular cytogenetic method allowing the comprehensive analysis of a tumor genome for chromosomal imbalances. In total, 23 primary squamous cell carcinomas without evidence of metastasis formation and 20 lymph node metastases were investigated. RESULTS: Prevalent changes observed in more than 50% of the primary tumors included deletions on chromosomes 3p, 4p/q, 5q, 6q, 9p, 11q, 13q, and 18q, and DNA overrepresentations on chromosomes 1p, 3q, 5p, 8q, 9q, 11q13, 16p, 17q, 19p, 20q, and 22q. To evaluate the differences between both groups we used a histogram representation, calculation of a difference histogram, and statistical analysis. The analysis revealed that the lymph node metastases were frequently characterized by deletions on chromosomes 10, 11, and 14. In particular, DNA loss of the chromosomal bands 5p12, 10p11.2-12, 10q21, 10q22-23, 10q24-26, 11p13-14, 11q24-25, and 14q22-24 were significantly associated with metastases formation. The statistical analysis indicated that particularly the deletions on chromosome 10q were highly significant markers for the incidence of lymph node metastases. CONCLUSION: Our data indicate that tumor phenotypes are determined by patterns of chromosomal alterations, and that 10q deletions may predict the metastatic phenotype in head and neck squamous cell carcinomas.

Biomarkers, Tumor↗
PubMed1999

Frequent allelic loss and homozygous deletion in chromosome band 8p23 in oral cancer.

Frequent loss of heterozygosity on chromosome 8p in a variety of human malignancies, including head and neck cancers, has suggested the presence of a tumor suppressor gene (or genes) associated with the pathogenesis of these cancers. To test the role of genetic alterations at 8p23 in oral carcinogenesis, we studied 51 squamous cell carcinomas of the head and neck and 29 oral squamous cell carcinoma cell lines for allelic loss using 7 microsatellite markers spanning approximately 5 cM of chromosome band 8p23. Twenty-three of 51 tumors (45%) and 23 of 29 cell lines (79%) showed allelic loss at 1 or more loci. Three cell lines showed homozygous deletion of loci within a 3 cM region defined by the markers D8S1781 and D8S262. Our results suggest that a tumor suppressor gene (or genes) is located in 8p23 and is associated with the development and/or progression of oral carcinomas.

Carcinoma, Squamous Cell↗
PubMed1999

[Genetic predisposition for the development of head and neck carcinomas].

BACKGROUND: While cigarette smoking and chronic alcohol consumption are the major risk factors for the development of head and neck cancer, it is assumed that genetic factors contribute to risk. Glutathione-S-transferase GSTM1 AB, GSTM3 BB and GSTP1 AA as well as TNF genotypes were determined from leucocyte DNA in 392 patients with head and neck carcinoma and 216 controls, with added immunohistochemical studies. Comparative genomic hybridization was used to screen for genetic alterations in the tumor tissue. RESULTS: While the frequency of GSTM1 AB was significantly lower in all head and neck carcinomas compared with controls, GSTM3 BB was significantly lower in the laryngeal and GSTP1 AA in the oral cavity/pharyngeal carcinoma cases; the frequency of the TNFb3 allele was higher in the laryngeal cases. Chromosomal alterations were specific for head and neck carcinomas, differing both in well differentiated and undifferentiated and in metastasizing and non-metastasizing tumors. CONCLUSIONS: Allelism at GST gene loci mediates susceptibility to head and neck carcinomas: GSTM1 AB is associated with a lower risk for all head and neck carcinomas, GSTM3 BB only for laryngeal carcinomas and GSTP1 AA only for oral cavity/pharyngeal carcinomas. The TNFb3 allele was significantly more frequent in laryngeal cancer patients. The genetic alterations in the tumor tissue are in line with the "tumor progression model". Genetic conditions are important from the first exposure with carcinogens up to late genetic events in the tumor tissue.

Alcohol Drinking↗
PubMed1998

Distinct regions of allelic imbalance on chromosome 10q22-q26 in squamous cell carcinomas of the lung.

The genetic mechanisms underlying the progression to the metastatic phenotype of lung cancer are poorly understood. We recently showed that small cell lung cancer (SCLC) and metastasizing squamous cell carcinomas are characterized by an increased incidence of allelic loss on chromosome 10q. In the present study we performed a deletion mapping using 24 polymorphic markers on chromosome 10q22-q26 in 39 squamous cell carcinomas (SCC) of the lung identifying 14 metastatic carcinomas (74%) and three non-metastatic SCC (15%) with allelic imbalance. The allelotype analysis indicated three regions of allelic loss that were clustered at the loci Afm086/D10S541, D10S185 and D10S1782/D10S169. A localized microsatellite instability was observed in two carcinomas for the markers D10S1686 and D10S1782. In addition the PTEN/MMAC1 gene was analysed by direct DNA sequencing and Southern blot analysis in 25 and 28 carcinomas, respectively, without detecting any genomic alterations. Similarly, no altered transcript was detected in 15 tumor cell lines and 20 primary tumors by Northern blot analysis or RT-PCR. In summary, three distinct regions of allelic imbalance were identified suggesting that multiple tumor suppressor genes on chromosome 10q contribute to tumor progression and metastases formation of lung cancer.

Alleles↗
PubMed1998

Genomic alterations associated with malignancy in head and neck cancer.

BACKGROUND: Comparative genomic hybridization (CGH) was performed on 50 primary head and neck squamous cell carcinomas (HNSCC) to discover molecular genetic alterations underlying the progression of these tumors. METHODS: In CGH, equal amounts of differently labeled tumor deoxyribonucleic acid (DNA) and normal reference DNA were hybridized simultaneously to normal metaphase chromosomes. They were visualized by different fluorochromes, and the signal intensities were quantitated separately as gray levels along the single chromosomes. The over- and underrepresented DNA segments were determined by computation of ratio images and average ratio profiles. RESULTS: Prevalent changes observed in more than 50% of the HNSCC included deletions of chromosomes 1p, 4, 5q, 6q, 8p, 9p, 11, 13q, 18q, and 21q and DNA overrepresentations of 11q13 as well as 3q, 8q, 16p, 17q, 19, 20q, and 22q. The calculation of ratio profiles of tumor subgroups revealed that well differentiated carcinomas (G1) were defined by the deletions of chromosomes 3p, 5q, and 9p together with the overrepresentation of 3q, suggesting the association with early tumor development. Accordingly, the undifferentiated tumors (G3) were characterized by additional deletions of chromosomes 4q, 8p, 11q, 13q, 18q, 21q, and overrepresentations of 1p, 11q13, 19, and 22q. CONCLUSION: Our data indicate that the CGH patterns of chromosomal imbalances may help to define the malignant potential of head and neck squamous cell carcinomas.

Carcinoma, Squamous Cell↗
PubMed1998

Allelic loss on chromosome 10q in human lung cancer: association with tumour progression and metastatic phenotype.

We analysed 78 carcinomas of the lung for allelic losses on chromosome 10q. The tumours were of different stage and grade and comprised 22 small-cell lung carcinomas (SCLC), 40 squamous cell carcinomas (SCC), 11 adenocarcinomas, four large-cell carcinomas and one carcinoid. They were investigated by six polymorphic markers located between 10q21 and 10qter. We observed a high incidence of loss of heterozygosity (LOH) in SCLC (91%) and metastatic SCC (56%). Non-metastatic SCC showed deletions in three cases (14%) and no LOH was found in the other types of non-small-cell lung cancer. The statistical analysis indicated that the presence of LOH correlated significantly with advanced tumour stages in the entire collective and in particular within the SCLC and SCC subgroups. For SCC, a positive association was found between LOH and metastases formation, while in SCLC the number of non-metastatic tumours was too small for a final conclusion. Whereas SCLC was frequently characterized by multiple allelic losses, suggesting the deletion of the entire chromosomal arm, SCC showed interstitial imbalances. A high incidence of allelic loss was observed between the markers D10S677 and D10S1223. The analysis of five informative cases suggested the presence of two non-overlapping regions between the loci D10S677/D10S1237 and D10S1213/D10S1223. In SCLC, we did not find mutations in the putative tumour-suppressor gene MXI1. The data indicate that LOH on chromosome 10q is associated with tumour progression in SCC and SCLC. Thus it may become a useful genetic marker in the assessment of the malignant potential of these tumour types.

Alleles↗
PubMed1998

[Effect of gene polymorphism on detoxifying glutathione-S-transferase enzymes on chromosomal stability of squamous epithelial carcinomas in the area of the head-neck].

BACKGROUND: While cigarette smoking and chronic alcohol consumption are the major risk factors for the development of head and neck cancer, it is assumed that genetic factors contribute to risk. MATERIAL AND METHODS: We examined genotype frequencies from leukocyte DNA of 269 laryngeal cancer patients, 123 pharyngeal cancer patients and 216 controls. Polymorphisms at different glutathione-S-transferase (GST) gene loci were investigated. Losses of heterozygosity (LOH) at 12 different chromosomal gene loci were determined in 37 of the study patients by comparing blood and tumor cell DNA. The relationship between high risk genotypes and the occurrence of LOH was investigated. RESULTS: Glutathione-S-transferase high risk genotypes were identified at the first and third genes of the M family (GSTM1, GSTM3) and the first gene of the P family (GSTP1). These high risk genotypes are seen to have a statistically significant influence on the occurrence of LOH in the tumor tissue. CONCLUSION: There is evidence that the polymorphisms studied play a role in the carcinogenic process by influencing the chromosomal fragility which may lead to the inactivation of tumor suppressor genes or the activation of oncogenes.

Alcohol Drinking↗
PubMed1998

[Cervical manifestation of malignant schwannoma].

BACKGROUND: Malignant schwannomas are rare malignant mesenchymal tumors often associated with neurofibromatosis. They occur less frequently in the head and neck than in other regions. PATIENT: A case history of a primary malignant schwannoma of the head and neck area in a 27-year-old man is reported. The tumor was located in the left submandibular region. The patient did not have any functional deficits. The tumor was totally removed. There have been no signs of either recurrence or metastasis within the two years following diagnosis and surgery. DISCUSSION: The microscopic and immunohistochemical findings are presented, and the importance and therapy of this very rare malignant tumor of the head and neck area are discussed. CONCLUSION: Malignant schwannoma in the head and neck region is rare. Radical resection is the treatment of choice.

Adult↗
PubMed1998

The glutathione S-transferase GSTP1 polymorphism: effects on susceptibility to oral/pharyngeal and laryngeal carcinomas.

We have examined the hypothesis that the polymorphic, glutathione S-transferase GSTP1 gene is a susceptibility candidate for squamous cell cancer of the oral/pharynx and larynx. We describe GSTP1 genotype frequencies in 380 cases and 180 controls. We found a lower frequency of GSTP1 AA in the oral/pharyngeal cases compared with controls (p = 0.003, odds ratio = 0.47) after correction for age and gender. We used an immunohistochemical approach to show widespread expression of the GSTP1 subunit throughout the pharynx and larynx. In uninfiltrated tissue, strong positivity was found throughout the squamous cell epithelium with the exception of the basal cell layer. The cilia of the respiratory epithelium of the larynx also showed positivity for GSTP1. In tumour tissue, expression of GSTP1 was similar in pharyngeal and laryngeal samples. These data are the first to show that polymorphism at GSTP1 mediates susceptibility to squamous cell cancer of the upper aerodigestive tract. No significant interactions were identified between GSTP1 and GSTM1, GSTM3, GSTT1 and the cytochrome P450 CYP1A1, CYP2D6 and CYP1A1 genotypes.

Alcohol Drinking↗