Biomedical subjects

A Roessner

Publications and source records attributed to A Roessner.

At least 91 records · Page 5Linked to original sources

PubMed1999

An evaluation of antigen retrieval procedures for immunoelectron microscopic classification of amyloid deposits.

The advantages of using immunoelectron microscopy in amyloid research and surgical pathology for the classification of amyloid deposits are well documented. The aim of this study was to improve single-labeling postembedding immunostaining by testing different antigen retrieval (AR) techniques. Etching and AR procedures were applied to sections from aldehyde-fixed and Epon-embedded autopsy specimens of patients who had suffered from generalized AA amyloidosis, systemic senile ATTR amyloidosis, or generalized kappa-light chain amyloidosis. The procedures used were no AR, H(2)O(2), saturated aqueous sodium metaperiodate (mPJ), heating in deionized water (dH(2)O), heating in sodium citrate buffer (SCB), heating in EDTA (each 91C, 30 min), and combinations of etching and heating. Little effect was evident after treatment with H(2)O(2), mPJ, and heating in dH(2)O, but the signal density markedly increased after heating in 1 mM EDTA. Heating in SCB affected immunolabeling with anti-transthyretin and anti-kappa-light chain, whereas no effect was achieved for immunolabeling with anti-AA amyloid. We concluded that AR may significantly improve immunostaining of specimens that have undergone conventional fixation and embedding procedures for electron microscopy. The effect of AR on the detection of amyloid fibril proteins was probably mediated in part through chelation or binding of metal ions by the AR medium. (J Histochem Cytochem 47:1385-1394, 1999)

Aged↗

PubMed1999

No microsatellite instability, but frequent LOH in liposarcomas.

To evaluate the significance of microsatellite instability (MI) and loss of heterozygosity (LOH) in the development of different histological subgroups of liposarcomas, we examined 28 tissue-samples from 21 patients and the corresponding non-neoplastic reference tissues. We investigated nine microsatellite loci and detected no MI. LOH for at least one marker was observed in 11 of 28 tumours (39%). Widespread allelic losses were a common characteristic of pleomorphic liposarcomas. Well-differentiated variants did not show LOH (p<0.003). Our findings support the idea that liposarcoma subgroups are defined by different spectra of genetic alterations. Inefficient DNA mismatch repair does not seem to be involved in the oncogenesis of liposarcomas.

DNA Repair↗

PubMed1999

Prognostic significance of telomerase activity in soft tissue sarcomas.

Only few reports on the prognostic significance of telomerase activity in human cancer exist. To find a new prognostic marker in soft tissue tumors, we investigated 60 soft tissue sarcomas of different histology and six benign tumors for telomerase activity. Telomerase activity was measured by using the non-radioactive PCR-based TRAP-assay. PCR products were analyzed on an automated fluorescence sequencer. Tumors of grade-II and grade-III histology showed a significantly poorer prognosis. Both disease-free (p<0.03) and the overall survival (p<0.02) were reduced in the highly malignant sarcoma patients. We found telomerase activity in 38.3% of the cases, there being a correlation with a more aggressive behavior of soft tissue sarcomas. Telomerase activity correlated with the grade of malignancy (p=0.04), but not with sex (p=0.64) or age (p=0. 48) of the patients. The total survival was significantly reduced in patients with telomerase-positive sarcomas (p=0.04). Both of the patients having grade I tumors with telomerase activity died of disease, whereas 10 of 11 patients with telomerase-negative grade I tumors are still alive. Only one of the benign tumors showed telomerase activity. We suggest that telomerase activity is a potential prognostic factor in malignant soft tissue tumors. Despite the histological heterogeneity of soft tissue tumors, single entities should be assessed for telomerase activity.

Adolescent↗

PubMed1999

Protease expression in dedifferentiated parosteal osteosarcoma.

BACKGROUND: Parosteal osteosarcoma with dedifferentiation provides a useful model to study tumor progression from an indolent locally aggressive neoplasm to highly lethal metastasizing malignancy. Up-regulation of the proteolytic enzymes participating in stromal degradation is known to promote invasive growth and metastasis of several human and experimental tumors. METHODS: The expression patterns of urokinasase plasminogen activator (u-PA), its cell-surface receptor (u-PAR), and cathepsin B were analyzed by immunohistochemical techniques in 11 cases of parosteal osteosarcoma and in 4 cases of dedifferentiated parosteal osteosarcoma. RESULTS: Both enzymes and the receptor were coexpressed in most tumor cells of parosteal and dedifferentiated parosteal osteosarcoma. Their expression was strikingly enhanced in the dedifferentiated high-grade component of the tumors. Tumor cells involved in bone production (ie, those adjacent to tumor produced bone trabeculae) exhibited equally strong expression of u-PA, u-PAR, and cathepsin B, regardless of their histologic grade. Expression of u-PA, u-PAR, and cathepsin B was undetectable in the "normalized" cells embedded in the well-developed tumor bone trabeculae. CONCLUSION: These data indicate that u-PA and its interacting molecules, such as u-PAR and cathepsin B, may have some contributory effects on the metastatic potential of tumor cells in dedifferentiated parosteal osteosarcoma.

Bone Neoplasms↗

PubMed1999

[In Process Citation]

OBJECTIVE: The objective of the study was to analyse the prognostic impact of several criteria for median survival and recurrence free interval in patients with uterine sarcomas. Factors included to our analysis were the staging according to FIGO, DNA content (ploidy), mitotic index, histology, the kind of primary therapy, grading and menopausal status. MATERIAL AND METHODS: Retrospectively, clinical data of 78 patients (41 leimyosarcomas, 23 carcinosarcomas = homologous malignant mixed Mullerian tumors, 14 endometrial stromal sarcomas--10 low grade, 4 high grade) were analysed. Additionally, in 36 of the cases mitoses were counted. Furthermore, DNA ploidy was determined using image cytometry on paraffine sections stained according to the Feulgen method. Receptor status was determined using immunohistochemical staining. Two and five year survival rates were 22% and 15%. There were 21 cases with local relapse and 27 cases with metastasis. RESULTS: The staging according to FIGO was the main prognostic factor, significantly influencing median survival time (p = 0.001) as well as the recurrence free interval (p = 0.03). There was a significant difference between median survival time compared to mitotic index (p = 0.014) and DNA ploidy (p = 0.02). A mitotic index < 10/10 HPF and diploidy were related with a better prognosis. Receptor status did not have an impact on median survival time. CONCLUSIONS: As our results suggest, DNA ploidy and mitotic index are likely to provide additional information for prognosis in patients with uterine sarcomas and could be used as criteria for selecting patients for adjuvant therapy.

Journal Article↗

PubMed1999

Prognostic relevance of p53 alterations and Mib-1 proliferation index in subgroups of primary liposarcomas.

For prognostic analyses of p53 alterations (p53 gene mutations + p53 immunopositivity) and Mib-1 proliferation index, we investigated 42 primary malignant lipomatous tumors for which complete clinical data and a long follow-up were available. p53 gene mutations were investigated by PCR-single strand conformation polymorphism-sequencing analysis, and immunohistochemistry was used to determine p53 protein expression and Mib-1 proliferation index. We found a mutation frequency of 14.3%. Nine liposarcomas (21%) were p53 immunopositive, and 11 (26.2%) had at least one p53 alteration. In myxoid liposarcomas, p53 alterations are not relevant to the presence or absence of round cell components. Pleomorphic liposarcomas showed a significantly higher proliferation index and more p53 alterations than myxoid or well-differentiated variants (P<0.001). When the Cox's regression analysis tumors of grade III histology (P = 0.005) was performed, the pleomorphic subtype (P = 0.016) and liposarcomas of retroperitoneal localization (P = 0.015) showed a significantly poorer prognosis. Moreover, we found that p53 alterations and high proliferation index correlated significantly with reduced overall survival. Their prognostic value seemed to be higher in myxoid than in pleomorphic liposarcomas. The metastasis-free survival was reduced in patients who had liposarcomas with p53 alterations (P = 0.171) or elevated proliferation index (P<0.016), reflecting a more aggressive behavior. In conclusion, the determination of p53 alterations and/or Mib-1 proliferation index is useful for assessing the prognosis of patients with liposarcomas and may especially be helpful in dividing different prognostic groups for patients with myxoid variants.

Adolescent↗

PubMed1999

[New findings in orthopedic pathology].

The term orthopedic pathology refers to bone- and joint-affecting diseases which are important for the orthopedic surgeon. In the report presented here, emphasis is placed on the membrane-associated proteolysis, which is essential for the degradation of the extracellular matrix. Matrix-degrading processes play a role not only in arthrosis but also in rheumatoid arthritis. Moreover, they are strongly associated with the problem of loosening of protheses, which is of utmost importance for the orthopedic surgeon. In these processes, major roles are played by the plasminogen activator system, plasmin, different matrix metalloproteinases, including the membrane type matrix metalloproteases and different cathepsins. A deeper insight into the function of these proteins and their influence on the matrix degradation in joint diseases will open the way for new diagnostic and therapeutic strategies. Investigations into a large number of chondrosarcomas have shown that for this type of bone lesions, urokinase plasminogen activator and cathepsin B are prognostic parameters that are independent of the differentiation grade. Also, in this context, investigations into the membrane-bound proteases will be of great practical and diagnostic value.

Arthroplasty, Replacement↗

PubMed1998

Antisense inhibition of urokinase: effect on malignancy in a human osteosarcoma cell line.

Expression of urokinase-type plasminogen activator (u-PA) strongly correlates with a malignant tumor cell phenotype. In the multistep process of metastasis, different cellular functions are influenced by urokinase. The enzyme is known to be effective via both proteolytical and signal transduction mechanisms. In the present study, the osteosarcoma cell line MNNG/HOS was transfected with a vector capable of expressing an antisense transcript, complementary to 1,021 bases of the 3' end of u-PA cDNA. This construct was most effective in reducing u-PA expression in previous experiments. Stably transfected antisense (as) cell lines were characterized and compared with the parental MNNG/HOS. Antisense transfection of MNNG/HOS gave the following results: (1) stable incorporation of the construct into the genome of as-clones, as detected by Southern blot analysis; (2) decreased mRNA level of u-PA, as detected by Northern blot analysis; (3) approximately 50% reduced enzyme expression in cell culture medium and cell homogenate; and (4) unchanged cellular proliferation activity and u-PAR expression. In further functional analysis, as-clones showed (1) significantly reduced invasion and motility in modified Transwell chambers (random migration and chemotaxis with collagen I as a chemoattractant); (2) significantly reduced adhesion on matrices of collagen I and vitronectin; (3) unchanged adhesion properties on Matrigel matrix; and (4) reduced metastatic potential to lungs and especially liver in chick embryos after i.v. infection into chorioallantoic membrane veins. Our data show that in MNNG/HOS urokinase influences cellular malignancy by promoting migration and selective adhesion. These specific functions were notable in addition to the effects on invasion and basement membrane degradation.

Animals↗

PubMed1998

No correlation of c-myc overexpression and p53 mutations in liposarcomas.

Although it is well known that oncogenesis is a multistep process involving the activation of normal cellular genes to become oncogenes and/or the inactivation of tumor suppressor genes, this process has seldom been investigated in soft tissue tumours. We screened a group of 36 liposarcomas for genetic abnormalities in the p53 tumour suppressor gene and c-myc oncogene. Altered c-myc gene expression was examined by differential RT-PCR assay. p53 Gene mutations in exons 4-8 were analysed by using PCR-SSCP analysis and direct sequencing. Elevated c-myc expression was found in 6 of 31 liposarcomas (19.4%). p53 Gene mutations were observed in 5 of 36 liposarcomas (13.9%). Both genetic alterations were associated with the histological subtype of liposarcomas. Whereas c-myc gene expression was a characteristic of myxoid/round cell liposarcomas, p53 gene mutations were found more frequently in pleomorphic variants. Liposarcomas of the well-differentiated subtype showed neither p53 gene mutations nor altered c-myc gene expression. Our results indicate that the c-myc oncogene and the p53 tumor suppressor gene do not seem to cooperate in the oncogenesis of liposarcomas.

Adult↗

PubMed1998

On telomere shortening in soft-tissue tumors.

PURPOSE: Specific simple DNA repeats occur at the telomeric ends of mammalian chromosomes. Loss of (G + C)-rich repeats can result in genetic instability, associated with tumorigenesis. So far, data on telomere shortening have not been available for different types of soft-tissue tumors. METHODS: Using tumor material and the blood of the corresponding patient, high-molecular-mass DNA was prepared by digestion with proteinase K and extraction with phenol/chloroform. A 10-microg sample of DNA was digested with the restriction enzyme HinfI. DNA fragments were separated in a 0.7% agarose gel, and in-gel hybridization was performed with the telomere-specific repeat probe (TTAGGG)3. RESULTS: Shortening of the telomere repeat was observed in 14/30 soft-tissue tumors; 5 tumors showed elongated telomere repeats, whereas the telomeres appeared unchanged in 11 tumors. Decreased telomere repeat length correlated with advanced age, DNA ploidy, and a higher proliferation index. There was no association between telomere repeat length and tumor grade. Interestingly, in contrast to other entities, all malignant schwannomas and leiomyosarcomas showed significantly reduced telomere lengths. An explanation for the telomere heterogeneity in liposarcomas may include differential telomerase reactivation in well and poorly differentiated tumors. CONCLUSIONS: Telomere shortening is frequent but not a uniform phenomenon in different types of soft-tissue tumor. Studies on telomerase activity should be performed in the same cohort of sarcomas.

Adult↗

PubMed1998

MDM2 amplification and loss of heterozygosity at Rb and p53 genes: no simultaneous alterations in the oncogenesis of liposarcomas.

PURPOSE: The present study aimed to investigate the status of alterations of the MDM2, Rb and p53 genes in a series of 45 liposarcomas. Furthermore, the possible correlation with histological and clinical parameters was studied. METHODS: MDM2 amplification was examined by non-radioactive Southern blot hybridization with a human MDM2 cDNA probe. Mutations in the p53 gene were screened by polymerase chain reaction/single-strand conformation polymorphism analysis and direct sequencing. To study loss of heterozygosity (LOH) at the tumor-suppressor genes Rb and p53, we used four polymorphic intragenic Rb markers (introns 1, 17, 20, and 25) and two p53 markers (intron 1 and exon 4). RESULTS: MDM2 amplification was found in 19 of 45 liposarcomas (42.2%). The frequency of LOH in Rb and p53 was nearly identical (22%). In 4 of 9 tumors (44.4%) with LOH, allelic loss was a concurrent event in both genes. Of 45 liposarcomas, 6 (13.3%) showed p53 mutations. Overall, alterations of the p53/MDM2/Rb pathway occurred in 30 of 45 liposarcomas (66.6%). In contrast to myxoid and pleomorphic variants, well-differentiated liposarcomas were characterized by a high frequency of MDM2 amplification, a lack of LOH of Rb and p53, and p53 mutations. CONCLUSIONS: Obviously MDM2 amplification and LOH at the Rh and p53 genes do not occur simultaneously in the oncogenesis of liposarcomas, as is the case for MDM2 amplification and p53 gene mutations (with one exception). We suggest that well-differentiated, myxoid and pleomorphic liposarcomas are characterized by a different pattern of molecular alterations.

Adult↗

PubMed1998

p53 gene mutations in osteosarcomas of low-grade malignancy.

Alterations in tumor suppressor gene p53, localized on chromosome 17p13, are considered to play a significant role in the initiation and, to some extent, even in the progression of various malignant tumors. In this respect, investigations on conventional highly malignant osteosarcomas have shown a mutation rate of approximately 20%. However, currently, data on the mutation rate in the group of variant histology osteosarcomas of low-grade malignancy do not exist. Therefore, we investigated a panel of low malignant entities (five low malignant intramedullary osteosarcomas grade 1; one intramedullary osteosarcoma grade 2; eight parosteal osteosarcomas, including one local recurrence grades 1 and 2, and five periosteal osteosarcomas grade 2) with polymerase chain reaction/single-strand conformation polymorphism (PCR-SSCP) analysis focusing on exons 4 to 8 of the p53 gene followed by direct sequencing. Point mutations were found in one low-grade osteoblastoma-like osteosarcoma and in two periosteal osteosarcomas grade 2 (one missense, one silent, and one nonsense mutation). This mutation rate of 15.7% (3 of 19) is comparable to that determined in highly malignant osteosarcomas. Moreover, the analysis of clinical data did not show any difference in the behavior of tumors with p53 mutations compared with those without. Therefore, we suggest that alterations in p53 gene are an early event in the tumorigenesis of malignant osteoblastic tumors without impact on progression of these tumors.

Adolescent↗

PubMed1998

Somatic DNA alterations in breast carcinomas of different lymph-node status by DNA fingerprint analyses.

The purpose of this study was to screen for somatic changes in invasive breast tumors by multilocus DNA fingerprints comparing normal (blood) and malignant tissue samples from 34 patients. The comparison of lymph node-positive and node-negative breast carcinomas was of primary interest. After restriction enzyme digestion with HinfI and HaeIII, altered banding patterns were detected by using the oligonucleotide probe (GTG)5 in 7 of 34 (20.5%) and in 3 of 34 (8.8%) tumors after hybridization with (GACA)4. The overall frequency of changes thus amounted to 29.4%. Because long (GACA)n repeat motifs, generating predominant DNA fingerprint bands, are localized on the short arms of the human acrocentric chromosomes, sequences that are important in breast carcinogenesis may be present in these regions. The overall methylation status of the DNA does not appear to be responsible for DNA fingerprint differences, as can be demonstrated with the restriction endonuclease HaeIII. DNA fingerprint differences did not correlate with tumor grade, stage, and hormone receptor status. Tumors with lymph-node metastases expressed DNA fingerprint differences more frequently.

Aged↗

PubMed1998

Development of osteoarthritis in the knee joints of Wistar rats after strenuous running exercise in a running wheel by intracranial self-stimulation.

The influence of excessive running load on the development of knee osteoarthritis (OA) was investigated in male Wistar rats. Running exercises were performed in a running wheel using intracranial self-stimulation to motivate Wistar rats to run daily distances of 500 m at 5 days/week. Hereby, ten rats ran a distance of 15 km within three weeks while a further ten rats run a total of 30 km within six weeks. Thirteen Wistar rats without running exercises served as controls. Complete knee joint sections of all rats were evaluated histologically using MANKINs grading system with categorization of the findings into non, mild moderate, and severe osteoarthritis. In addition, immunoreactivity of the chondrocytes to MMP-3 as an important cartilage degrading enzyme in OA was assessed by immunostaining with monoclonal MMP-3 IgG antibodies. Histological assessment of the knee joint sections revealed a significant increase in osteoarthritic changes with higher running load. While in rats with 15 km running all but two knee joints showed mild OA, moderate OA was the predominant finding in rats with 30 km running. In contrast, no OA was found in the controls. Immunostaining for MMP-3 revealed a significant increase in immunoreactivity of the chondrocytes to MMP-3 with higher running load, indicating a running load-depending production of this cartilage-degrading enzyme in the course of increasing OA. Compared to 47.4% immunoreactive chondrocytes to MMP-3 in the controls, this ratio rose to 70.4% in rats with 15 km running and even up to 89.9% in rats with 30 km running. In conclusion, in Wistar rats, excessive running load leads to marked, running distance-depending osteoarthritic changes which are caused, at least in part, by an increase in MMP-3 production rising with greater running distance. Within this exercise model of OA, intracranial self-stimulation is an effective method to motivate Wistar rats to extremely excessive running in a running wheel. This model offers a wide range of further approaches to studying different processes of the development of OA.

Animals↗

PubMed1998

Alveolar soft part sarcoma of the uterine corpus. Report of two cases and review of the literature.

Alveolar soft-part sarcoma (ASPS) is a rare tumor of uncertain histogenesis, mainly localized in the extremities and less frequently found in the head, neck and trunk. The present report describes two cases of ASPS localized in the uterus. In general, this entity is very rarely encountered in the female genital tract. Including the two cases presented here, 27 patients have been described in the literature. Whereas the prognosis for ASPS in soft tissues is usually poor (most of the patients died of lung metastases), those localized in the female genital tract are associated with a much better survival. This could be explained by the fact that their diameter seldom exceeds 5 cm, the size which is regarded as being the critical prognostic limit. Histologically, both tumors showed the same characteristics as known for ASPS in other localizations: organoid or nest-like arrangement of tumor cells; rounded or polygonal cells with cytoplasm of varying density; thin-walled, sinusoidal vascular spaces between tumor cell nests. Immunohistochemically, we found positivity for desmin and, to a lesser extent, for vimentin. Cytokeratin was negative, which is important in differential diagnosis to other rare uterine neoplasias like clear cell (mesonephroid) adenocarcinomas or metastases.

Adult↗

PubMed1998

p53 and ras mutations in Ewing's sarcoma.

The role of tumor suppressor genes and oncogenes in the development of Ewing's sarcoma has not yet been fully clarified. In this study, we analyzed the frequency of p53 tumor suppressor gene mutation in exons 4-8 by PCR-SSCP and direct sequencing, and the expression of p53-protein in Ewing's sarcoma (ES) by using immunohistochemistry. The overexpression of MDM2, which acts as a functional inactivator of p53, was studied by immunohistochemistry. In addition, a screening for point mutations in the hot spot regions codon 12 and 13 of exon 1 and codon 61 of exon 2 of ras-genes (H-ras, N-ras, K-ras) was performed. In one case, a p53 gene mutation could be confirmed in codon 238 of exon 7 (1/24). Overexpression of MDM2 was found in five cases; in ras-genes, no mutations were detected. Compared with other highly malignant mesenchymal pediatric tumors such as osteosarcomas, mutations of p53 and ras in Ewing's sarcomas are an extraordinarily rare event. However, their frequency is comparable to that of PNET, suggesting that the low incidence of these mutations in ES and PNET could be group-specific for tumors of neuroectodermal genesis.

Adolescent↗

PubMed1998

The pS2 protein in colorectal carcinomas and metastases.

Expression of pS2 protein in 50 primary tumors, metastases and recurrent tumors of colorectal carcinomas has been analyzed by immunohistochemistry. Sixty percent of the primary tumors were at least focally positive for the antigen. There was no correlation between pS2 expression and histologic grade of the lesions. In contrast, pS2 expression in T4 and T3 tumors was significantly higher than in T2 carcinomas. Immunoreactions in carcinomas with distant metastases (MI) were stronger than in M0 cases. However, this difference did not reach statistical significance. The presence of lymph node metastases did not correlate with pS2 expression. High expression of pS2 in T4 and T3 carcinomas together with the finding of pronounced expression of the antigen at invasion fronts in single cases could be interpreted as a function in tumor cell invasion and motility. However, in metastases and recurrent tumors, pS2 expression did not differ from primary lesions (53% positive lesions). All in all, under consideration of the latter finding in particular and together with the randomly distributed immunopositive tumor cells and cell clusters in the majority of cases, it is more likely that the expression pattern of pS2 in colorectal carcinomas is a result of overall tumor cell heterogeneity.

Carcinoma↗

PubMed1998

Immunohistochemical analysis of several proteolytic enzymes as parameters of cartilage degradation.

Osteoarthritis is the most common joint disease in humans. It is characterized by a gradual loss of extracellular matrix components of articular cartilage such as collagen and proteoglycan. Presently, however, emphasis is placed on enzymes exerting a strong influence on cartilage degradation. These enzymes include matrix metalloproteinases (MMP), their specific inhibitors (TIMP) and the plasminogen activator/inhibitor system. We applied monoclonal antibodies against MMP-1, -2, -3, -9 and their inhibitors TIMP-1/-2, as well as against urokinase-plasminogen activator u-PA and its inhibitor PAI to investigate their influence on articular cartilage degradation in patients with varusgonarthritis. We examined the cartilage of the lateral and medial compartments of 20 tibia plateaus, which can present with slight and severe cartilage degradations at the same time. In doing so, we tried to show whether or not immunohistological detection of enzymes could serve as a parameter for chondral degradation. The strongest immunoreaction for all enzymes was noted in the superficial layer of articular cartilage both medially and laterally. Between medial and lateral compartments, however, there were striking differences in the immunoreaction intensity of chondrocytes for MMP-1 and -3 as well as for TIMP-1 and u-PA. We noted that in cartilage with more advanced degradation, the immunoreaction for these enzymes was significantly higher in medial than in lateral compartments (p < 0.05). At the immunohistological level, a direct correlation between the grade of cartilage degradation and immunoreaction intensity was found. Our results corroborate the assumption that the expression of certain matrix-degradating enzymes serves as a parameter for the grade of cartilage degradation.

Aged↗