Biomedical subjects

M Dietel

Publications and source records attributed to M Dietel.

At least 109 records · Page 6Linked to original sources

PubMed1997

Patterns of chromosomal alterations in metastasizing and nonmetastasizing primary head and neck carcinomas.

In an attempt to define chromosomal alterations that are associated with the metastatic phenotype, we investigated a total of 29 metastasizing (pN+) and 19 non-metastasizing (pN0) head and neck squamous cell carcinomas by comparative genomic hybridization (CGH). The analysis indicated that the pN0 tumors carried preferentially overrepresentations of chromosomes 5p, 6p, and 7p and that the pN+ tumors were frequently characterized by deletions on chromosomes 7q, 10q, 11p, 11q, 15q, and 20p and overrepresentations of the chromosomes 19q and 20q. In particular, the use of difference histograms and statistical analysis indicated that the deletions on chromosomes 10q25-q26 and 11p13-p14 were highly significant for metastasizing carcinomas. The findings on chromosome 10q were supported by loss of heterozygosity analysis in the primary tumors and eight synchronous lymph node metastases using four microsatellite polymorphisms. The data suggest that distinct patterns of genetic lesions are responsible for the metastatic phenotype of head and neck squamous cell carcinomas.

Carcinoma, Squamous Cell↗

PubMed1997

Identification of allelic losses in benign, borderline, and invasive epithelial ovarian tumors and correlation with clinical outcome.

BACKGROUND: The somatogenetic alterations that lead to the development of benign adenomas, borderline tumors, and invasive ovarian carcinomas are not well understood. This study investigated allelic losses in these three types of ovarian tumors. METHODS: Twelve genetic regions on chromosomes 2q, 5q, 6p, 6q, 9p, 11q, 17p, 17q, 18q, and 22q were analyzed by polymerase chain reaction for loss of heterozygosity (LOH). The study was performed on formalin fixed, paraffin embedded tissue samples from 72 invasive ovarian carcinomas, 35 ovarian tumors of borderline malignancy, and 25 benign ovarian adenomas. RESULTS: LOH was found in only 8% of the analyzed adenomas (at 2q21 and 17p13) and 11% of the borderline tumors (at 2q21, 5q21, 6p21, 17p13, and 17q21). Allelic losses were noted for 77.7% of all of the invasive carcinomas analyzed. The frequency of LOH was 56% at a locus near 17p13 (TP53) and 40.5% at 17q21 (BRCA1). LOH was observed in 30.4% of informative cases at 5q21 and in 21.4% at chromosome 18q21. The chromosomal regions 2q21-22 and 9p21 had deletions at frequencies of 32.4% and 25%, respectively. International Federation of Gynecology and Obstetrics stage and the presence of LOH correlated significantly with survival but were not independent predictors of survival. Serous subtypes of invasive carcinoma were significantly more prone to deletions than nonserous tumors. CONCLUSIONS: The results of this study suggest that LOH occurs only occasionally in adenomas and borderline tumors, whereas it is frequently observed in invasive ovarian carcinomas. Therefore, other genetic events seem to be involved in early ovarian tumor development. However, the presence of multiple allelic losses is an indicator of higher stages of invasive carcinoma.

Adenoma↗

PubMed1997

Patterns of chromosomal imbalances in adenocarcinoma and squamous cell carcinoma of the lung.

Comparative genomic hybridization was used to screen 25 adenocarcinomas and 25 squamous cell carcinomas of the lung for chromosomal imbalances. DNA copy number decreases common to both entities were observed on chromosomes 1p, 3p, 4q, 5q, 6q, 8p, 9p, 13q, 18q, and 21q. Similarly, DNA gains were observed for chromosomes 5p, 8q, 11q13, 16p, 17q, and 19q. Adenocarcinomas showed more frequently DNA overrepresentations of chromosome 1q and DNA losses on chromosomes 3q, 9q, 10p, and 19, whereas squamous cell carcinomas were characterized by increased overrepresentations of chromosome 3q and 12p as well as deletions of 2q. For the first time, we used a histogram representation and statistical analysis to evaluate the differences between both tumor groups. In particular, the overrepresentation of the chromosomal band 1q23 and the deletion at 9q22 were significantly associated with adenoid differentiation, whereas the DNA loss of chromosomal band 2q36-37 and the overrepresentations at 3q21-22 and 3q24-qter were statistically significant markers for the squamous cell type. The study strengthens the notion that different tumor subgroups of the respiratory tract are characterized by distinct patterns of chromosomal alterations.

Adenocarcinoma↗

PubMed1997

Decreased drug accumulation in a mitoxantrone-resistant gastric carcinoma cell line in the absence of P-glycoprotein.

An established gastric-carcinoma cell line, EPG85-257P, is extremely sensitive to mitoxantrone (IC50, 0.12 ng/ml). Stepwise selection with mitoxantrone for 3 years resulted in a cell line (EPG85-257RN) that is 7,056-fold resistant to mitoxantrone (IC50, 846 ng/ml) and displays cross-resistance to the topoisomerase(topo)-II poisons ametantrone (411x), etoposide (112x) and teniposide (60x) as well as the topo-I poisons 7-ethyl-10-hydroxycamptothecin (331x) and topotecan (58x). We now show that this resistance is multifactorial. Western blotting revealed a 5-fold decrease in topo-IIalpha polypeptide in the mitoxantrone-resistant cells. Immunohistochemistry and Western blotting failed to demonstrate P-glycoprotein overexpression. Formation of trapped topo-II-DNA complexes in the resistant cells required higher mitoxantrone concentrations than in parental cells, even though nuclei isolated from the EPG85-257RN cells formed cleavage complexes normally. In agreement with these observations, which suggest the possibility of a defect in mitoxantrone accumulation, examination of mitoxantrone accumulation in both cell lines by confocal laser microscopy revealed that the EPG85-257RN cells accumulate less mitoxantrone at steady state. From these results, we propose that mitoxantrone accumulation, along with alterations in topo-IIalpha expression, contribute to the resistance to mitoxantrone observed in these cells.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1997

Cloning and characterization of human cDNAs encoding a protein with high homology to rat intestinal development protein OCI-5.

We constructed a lambda complementary DNA expression library from the mitoxantrone-resistant human gastric carcinoma cell line EPG85-257RNOV. The library was screened by differential hybridization (resistant cell line against non-resistant cell variant). By this procedure we found five independent cDNA clones representing one single gene that has much higher expression in the mitoxantrone-resistant cell line EPG85-257RNOV than in the non-resistant variant EPG85-257P. One of the cDNA clones (MXR7) contains a complete open reading frame (ORF) encoding a 580-amino acid polypeptide. Amino acid and nucleotide sequence analysis revealed that this gene codes the human variant of a rat intestinal development protein OCI-5.

Amino Acid Sequence↗

PubMed1997

Primary small-cell lung carcinomas and their metastases are characterized by a recurrent pattern of genetic alterations.

Small-cell lung cancer (SCLC) represents a group of highly malignant tumors giving rise to early and widespread metastases. We used comparative genomic hybridization in autoptic tumor specimens from 10 patients to discover genetic alterations that are associated with tumor progression and potentially with the metastatic phenotype. Ten primary SCLC and 16 corresponding metastases were investigated with a maximum of 4 tumors per case. Prevalent changes observed in more than 60% of the primary tumors and their metastases included deletions on chromosomes 3p, 4q, 5q, 10q, 13q and 17p, and DNA over-representations on chromosomes 3q and 5p. The number of common alterations in the primary tumors and the related metastases outnumbered the differences, indicating a clonal relationship. Within the lesions of the same patient, differences were found between the primary tumor and the metastases as well as between metastases of distinct organ sites. However, no specific alteration was significantly associated with the metastatic phenotype. We suggest that the high malignancy of SCLC is defined by the above-mentioned pattern of aberrations.

Aged↗

PubMed1997

[Modern fetal autopsy oriented to clinical demands using technical information methods].

Modern ultrasonic diagnostic instruments with high resolution and color Doppler sonography allow the obstetrician to describe pathological findings very precisely and at an early stage of pregnancy. The use of high-resolution ultrasound makes it possible to detect heart malformations already between the 8th and 10th week of gestation. This development has essentially changed the clinical requirements on fetal autopsy which in its traditional way no longer meets the increased demands. Unless the pathologists faces this challenge the importance of fetal autopsy will diminish. Modern image databases and communication techniques allow the pathologist to have direct access to text and images of pre-findings by other clinics. Great importance, however, must be attached to the interdisciplinary cooperation with obstetricians and geneticists. We report on routine fetal autopsy by using an interdisciplinary database an the Charité.

Autopsy↗

PubMed1997

Acute right-sided heart failure due to hemorrhage into a pericardial cyst.

This is a description of a rare complication of a pericardial cyst with spontaneous internal hemorrhage and following tamponade. The noninvasive diagnosis was done by transesophageal echocardiography and computed thoracic tomography. The cyst was thoracoscopically removed and pathologically examined. This case demonstrates a rare but important and life-threatening complication of mostly asymptomatic pericardial cysts.

Acute Disease↗

PubMed1997

Utility of 123C3 monoclonal antibody against CD56 (NCAM) for the diagnosis of small cell carcinomas on paraffin sections.

CD56 is immunohistochemically detectable in virtually all small cell carcinomas on frozen sections. The authors retrospectively tested the usefulness of the monoclonal antibody 123C3 against CD56 to differentiate pulmonary and extrapulmonary small cell carcinomas from nonneuroendocrine non-small cell carcinomas by paraffin-section immunohistochemistry after antigen retrieval. The study included 70 small cell carcinomas and 344 primary and metastatic nonneuroendocrine carcinomas of various primary sites. The staining results were compared with specific neuroendocrine markers (CD57, Chromogranin A, Synaptophysin). The monoclonal antibody 123C3 diffusely stained most small cell carcinomas with a strong membranous pattern (sensitivity: 0.99). The staining intensity was not diminished in areas with crush artifacts or after decalcification. The neuroendocrine markers had a combined sensitivity of only 0.44 for small cell carcinomas. With regard to nonneuroendocrine carcinomas, the 123C3 antibody stained 7 of 28 ovarian carcinomas, 6 of 30 renal cell carcinomas, 2 of 10 endometrial carcinomas, two of three nonneuroendocrine large cell carcinomas of the lung, 1 of 38 adenocarcinomas, and 4 of 52 squamous cell carcinomas of the lung. Urothelial carcinomas, hepatocellular carcinomas, squamous carcinomas of the head/neck and cervix uteri, as well as adenocarcinomas of the breast, stomach, colon, pancreas, and prostate, showed no immunoreactivity for CD56. The specificities of 123C3 and the combined neuroendocrine markers for small cell carcinomas were 0.94 and 0.95, respectively. The authors conclude that monoclonal antibody 123C3 might be useful for the immunohistochemical differentiation of small cell carcinomas from nonneuroendocrine carcinomas on paraffin sections, especially in small and crushed biopsy specimens.

Antibodies, Monoclonal↗

PubMed1997

Small-cell lung cancer is characterized by a high incidence of deletions on chromosomes 3p, 4q, 5q, 10q, 13q and 17p.

The genetic mechanisms that define the malignant behaviour of small-cell lung cancer (SCLC) are poorly understood. We performed comparative genomic hybridization (CGH) on 22 autoptic SCLCs to screen the tumour genome for genomic imbalances. DNA loss of chromosome 3p was a basic alteration that occurred in all tumours. Additionally, deletions were observed on chromosome 10q in 94% of tumours and on chromosomes 4q, 5q, 13q and 17p in 86% of tumours. DNA loss was confirmed by loss of heterozygosity (LOH) analysis for chromosomes 3p, 5q and 10q. Simultaneous mutations of these six most abundant genetic changes were found in 12 cases. One single tumour carried at least five deletions. DNA under-representations were observed less frequently on chromosome 15q (55%) and chromosome 16q (45%). The prevalent imbalances were clearly indicated by the superposition of the 22 tumours to a CGH superkaryogram. In our view, the high incidence of chromosomal loss is an indication that SCLC is defined by a pattern of deletions and that the inactivation of multiple growth-inhibitory pathways contributes in particular to the aggressive phenotype of that type of tumour.

Aged↗

PubMed1997

Nuclear localization and increased levels of transcription factor YB-1 in primary human breast cancers are associated with intrinsic MDR1 gene expression.

Breast cancers are either primarily resistant to chemotherapy (intrinsic resistance), or respond to chemotherapy but later recur with a multidrug-resistant phenotype because of overexpression of the multidrug transporter P-glycoprotein. The MDR1 gene encoding P-glycoprotein may be transcriptionally regulated by a Y-box transcription factor. We now report that, in multidrug-resistant MCF-7 breast cancer cells, nuclear localization of YB-1 is associated with MDR-1 gene expression. In drug-sensitive MCF-7 cells, however, YB-1 was localized to the cytoplasm. Regulated overexpression of YB-1 in drug-sensitive diploid breast epithelial cells induced MDR-1 gene expression and multidrug resistance. In 27 out of 27 untreated primary breast cancers, YB-1 protein was expressed in the cytoplasm although it was undetectable in normal breast tissue of these patients. In a subgroup of tumors (9/27), however, YB-1 was also localized to the nucleus and, in these cases, high levels of P-glycoprotein were present. These results show that in a subset of untreated primary breast cancers, nuclear localization of YB-1 protein is associated with intrinsic multidrug resistance. Our data show that YB-1 has an important role in controlling MDR1 gene transcription and this finding provides a basis for the analysis of molecular mechanisms responsible for intrinsic multidrug resistance in human breast cancer.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1997

Immunohistochemical differentiation of metastases of renal carcinomas versus other carcinomas with anti-gamma GT monoclonal antibody 138H11.

AIMS: Adenocarcinomas account for about 60% of metastatic cancers of unknown primary (CUP) site. In such a clinical CUP situation, histopathologists are challenged to differentiate renal cell carcinomas (RCC) from other adenocarcinomas with similar immunophenotypes, especially chemotherapeutically treatable mammary and ovarian carcinomas. METHODS AND RESULTS: Recently, we produced a monoclonal antibody (mAb), designated 138H11, against human gamma-glutamyl-transferase (gamma GT), which stained over 98% primary clear cell and chromophilic RCC on frozen sections. The 138H11 epitope could not be stained using conventional techniques in most paraffin-embedded sections of the same origin, due to destruction by formalin fixation below the detection level. Here, we demonstrate that mAb 138H11 can specifically stain gamma GT in paraffin-embedded primary and metastatic RCC after enhancement with an ultrasensitive immunohistochemical method. We analysed a selected subgroup of adenocarcinomas with immunophenotypes which would not allow a differentiation from RCC in a CUP situation. We found a predominantly membranous expression of the 138H11 target antigen in 26/51 primary RCC and 15/ 34 metastatic RCC. In contrast, all 43/43 primary ovarian and bronchial carcinomas as well as 54/54 metastases of ovarian, mammary, bronchial and gastric carcinomas were negative for mAb 138H11. CONCLUSIONS: The data suggest that mAb 138H11 is useful for the immunohistochemical differentiation of RCC from other metastatic adenocarcinomas if the primary site of the tumour is not known.

Antibodies, Monoclonal↗

PubMed1997

Immunohistochemical detection of CD5 with monoclonal antibody 4C7 on paraffin sections.

CD5 is useful for the classification of low-grade B-cell lymphomas, because it is aberrantly expressed in B-cell chronic lymphocytic leukemias/small lymphocytic lymphomas (B-CLLs/SLLs) and mantle cell lymphomas (MCLs), but not in the other well-described low-grade B-cell lymphomas. Therefore, we tested the utility of monoclonal antibody (MAb) 4C7 to detect CD5 on paraffin sections of 22 cases with low-grade B-cell lymphomas and 4 cases with high-grade B-cell lymphomas and compared the results with CD5 detection by analysis of fresh tissue with a fluorescent-activated cell sorting (FACS). After heat-induced epitope retrieval we could detect CD5 on paraffin sections in all MCLs and B-CLLs/SLLs, identical to the results of flow cytometry. Eleven of 12 cases that showed no CD5 expression by FACS analysis were also negative on paraffin sections. In only one case of a presumed blastoid MCL, CD5 was detectable by immunohistochemistry but not by FACS analysis. We conclude that MAb 4C7 against CD5 is a useful paraffin-reactive marker, especially to correctly identify MCLs on paraffin sections.

Antibodies, Monoclonal↗

PubMed1997

[Comparative genomic hybridization of bronchial carcinomas and their metastases].

We analysed 150 carcinomas of the respiratory tract and their metastases by Comparative Genomic Hybridization (CGH), a screening method for the detection of chromosomal imbalances in solid tumors. Small cell lung carcinomas (SCLC) and non-small cell lung carcinomas (NSCLC) revealed characteristic patterns of chromosomal alterations with overlapping and specific lesions in both tumor groups. SCLC were defined by a pattern of deletions on chromosomes 3p, 4q, 5q, 10q, 13q and 17p along with overrepresentations of chromosomes 3q and 5p. In contrast, NSCLC carried frequently deletions on chromosomes 1p, 3p, 4q, 5q, 6q, 8p, 9p, 13q, 18q and 21q along with overrepresentations of chromosomes 5p and 11q13. The deletions of the chromosomal band 2q36-q37 together with amplifications of chromosome 3q were statistically significant lesions of squamous cell carcinomas (SCC) whereas adenocarcinomas were characterized in particular by the overrepresentation of chromosome 1q23 and the deletion on chromosome 9q22. The comparison of primary and metastatic tumors revealed that the deletion of chromosome 10q was a statistically significant marker of tumor progression and metastatic phenotype in SCC and SCLC. In conclusion, the data indicate that tumor histotypes and phenotypes are associated with patterns of chromosomal alterations which give important additional information for the classification of human lung carcinomas.

Adenocarcinoma↗

PubMed1997

Image analysis for comparative genomic hybridization based on a karyotyping program for windows.

OBJECTIVE: To describe the image processing and analysis techniques we developed for the quantitative analysis of comparative genomic hybridization (CGH). STUDY DESIGN: A system for CGH cytometry is based on a semiautomated karyotyping program using the Windows graphic user interface. RESULTS: After alignment and normalization of the fluorescence images of the test genome (FITC) and reference genome (TRITC), the chromosomes are segmented and arranged as a CGH karyogram. The CGH karyograms from different metaphases of one tumor sample are represented as a CGH sum karyogram. Mean DAPI, FITC, TRITC and RATIO images, as well as ratio profiles with the 95% confidence interval, can be displayed. CONCLUSION: Representation of CGH results in the form of pseudocolored mean ratio chromosomes enhances the visibility of the method. The ratio profile plus confidence interval facilitates the identification of preparation artifacts and the classification of chromosomal imbalances. The sum karyograms of several tumors can be combined into a CGH superkaryogram of a tumor subgroup; that helps identify recurrent DNA changes in a tumor and might lead to genetic tumor classification based on CGH.

DNA, Neoplasm↗

PubMed1996

Distinct patterns of chromosomal alterations in high- and low-grade head and neck squamous cell carcinomas.

Comparative genomic hybridization was performed on 30 primary head and neck squamous cell carcinomas. Fractional or entire DNA loss of chromosome 3p was a basic finding that occurred in 29 cases (97%). Additional DNA underrepresentations were observed in more than 50% of the cases on chromosomes 1p, 4, 5q, 6q, 8p, 9p, 11q, 13q, 18q, and 21q. Deletions on chromosomes 3p, 13q, and 17p were confirmed by loss of heterozygosity analysis. Entire or partial DNA copy number increases were identified for chromosome 3q in 26 cases (87%) with high-level amplifications at 3q24 and 3q27-qter. Overrepresentations were found in decreasing order of frequency at 11q13 (70%), 8q (57%), 19q (50%), 19p (47%), and 17q (47%). The use of comparative genomic hybridization superkaryograms of the group of well-differentiated carcinomas (G1) indicated that the deletions on chromosomes 3p and 9p along with the overrepresentation of 3q are associated with early tumor development. Accordingly, the undifferentiated tumors (G3) were characterized by additional deletions on chromosomes 4q, 8p, 11q, 13q, 18q, and 21q and overrepresentations on 1pter, 11q13, 19, and 22q, suggesting that these changes are preferentially associated with tumor progression.

Carcinoma, Squamous Cell↗

PubMed1996

Cloning of a human cDNA encoding a protein with high homology to yeast methionyl-tRNA synthetase.

A composite 2779-bp cDNA that encodes human cytoplasmic methionyl-tRNA synthetase (MetRS) has been constructed from partial cDNA clones derived from the gastric carcinoma cell line EPG85-257RNOV and the nucleotide sequence has been determined. The open reading frame (ORF) encodes a 900 amino acid (aa) protein with a predicted molecular mass of 101 kDa. Northern blotting analysis of total RNA extracted from human gastric carcinoma cells demonstrated a single band with a mobility corresponding to a size of 3.0 kb.

Amino Acid Sequence↗

PubMed1996

Methods to detect P-glycoprotein-associated multidrug resistance in patients' tumors: consensus recommendations.

Multidrug resistance (MDR), especially that associated with overexpression of MDR1 and its product, P-glycoprotein (Pgp), is thought to play a role in the outcome of therapy for some human tumors; however, a consensus conclusion has been difficult to reach, owing to the variable results published by different laboratories. Many factors appear to influence the detection of Pgp in clinical specimens, including its low and heterogeneous expression; conflicting definitions of detection end points; differences in methods of sample preparation, fixation, and analysis; use of immunological reagents with variable Pgp specificity and avidity and with different recognition epitopes; use of secondary reagents and chromogens; and differences in clinical end points. Also, mechanisms other than Pgp overexpression may contribute to clinical MDR. The combined effect of these factors is clearly important, especially among tumors with low expression of Pgp. Thus, a workshop was organized in Memphis, Tennessee, to promote the standardization of approaches to MDR1 and Pgp detection in clinical specimens. The 15 North American and European institutions that agreed to participate conducted three preworkshop trials with well-characterized MDR myeloma and carcinoma cell lines that expressed increasing amounts of Pgp. The intent was to establish standard materials and methods for a fourth trial, assays of Pgp and MDR1 in clinical specimens. The general conclusions emerging from these efforts led to a number of recommendations for future studies: (a) although detection of Pgp and MDR1 is at present likely to be more reliable in leukemias and lymphomas than in solid tumors, accurate measurement of low levels of Pgp expression under most conditions remains an elusive goal; (b) tissue-specific controls, antibody controls, and standardized MDR cell lines are essential for calibrating any detection method and for subsequent analyses of clinical samples; (c) use of two or more vendor-standardized anti-Pgp antibody reagents that recognize different epitopes improves the reliability of immunological detection of Pgp; (d) sample fixation and antigen preservation must be carefully controlled; (e) multiparameter analysis is useful in clinical assays of MDR1/Pgp expression; (f) immunostaining data are best reported as staining intensity and the percentage of positive cells; and (g) arbitrary minimal cutoff points for analysis compromise the reliability of conclusions. The recommendations made by workshop participants should enhance the quality of research on the role of Pgp in clinical MDR development and provide a paradigm for investigations of other drug resistance-associated proteins.

ATP Binding Cassette Transporter, Subfamily B, Mem↗