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T Bauknecht

Publications and source records attributed to T Bauknecht.

At least 55 records · Page 3Linked to original sources
PubMed1994

Recurrent cytogenetic aberrations and loss of constitutional heterozygosity in ovarian carcinomas.

Cancer is regarded as the result of the accumulation of multiple genetic changes leading to either the activation of oncogenes and increased expression of mitogenic pathways or the inactivation of tumor suppressor genes. It was our interest to investigate malignant ovarian tumors with cytogenetic and molecular techniques to evaluate their consistent genetic alterations. Cytogenetic analysis was performed on 30 short-term cultured ovarian carcinomas. Fifteen tumors revealed clonal cytogenetic abnormalities, 10 of which had very complex karyotypes. The most consistent finding was a 19p+ marker chromosome which was present in half of the cytogenetically abnormal tumors with complex chromosome aberrations. Four tumors showed structural rearrangements resulting in loss of 11p13-pter material. Parallel DNA extracts from 18 tumor samples and corresponding normal white blood cells were analyzed by Southern blotting using 4 polymorphic probes spanning the region 11p15.1 to 11p15.5 and one polymorphic probe mapped to 19p13. Regarding the 11p probes, reduction to homozygosity in the tumor DNA was found in 9 of 17 informative cases. Loss of 19p alleles was found in 5 of 13 informative tumors. Our findings suggest that tumor suppressor genes located on the short arms of chromosomes 11 and 19 are involved in the development of human ovarian cancer.

Adult↗
PubMed1994

Phase II study of pirarubicin combined with cisplatin in recurrent ovarian cancer.

Although 50%-80% of patients with advanced ovarian cancer demonstrate an objective response after platinum-based chemotherapy, a majority of these patients will ultimately experience a relapse of their disease. Effective second-line treatment for these patients is of the most importance. We performed a phase II study with cisplatin and pirarubicin (each drug 50 mg/m2 i.v. every 28 days) in 17 patients with relapsed or persistent ovarian carcinoma. All patients had received platinum-containing primary chemotherapy. Overall survival from the time of diagnosis was 38.3 months (45.3 months in relapsed ovarian carcinoma and 28.3 months in ovarian carcinoma persisting after primary chemotherapy). Survival from entrance into the study was 13.0 months (14.2 months in relapsed disease and 11.2 months in refractory disease). Time to progression was 10.3 months. An objective response was observed in 4 patients and another 3 patients had stable disease. Major toxicity consisted of emesis (grade III/IV in 60/64 courses) and myelosuppression WHO grade III/IV in 15 courses. Neurotoxicity occurred in 3 patients and nephrotoxicity in 1 patient. Alopecia occurred in 12 patients. Tachycardia and other low-grade heart toxicities were observed after 5 courses. Dose reduction was necessary because of severe myelosuppression in 4 courses and because of nephrotoxicity in 1 course. Delay of subsequent chemotherapy courses for more than 7 days was necessary after 13 courses and was always due to myelosuppression. The dose-limiting toxicity of combination chemotherapy with cisplatin and pirarubicin is myelosuppression. Response and survival rates are superior in patients with relapsed disease compared to patients with resistant ovarian carcinoma.

Adolescent↗
PubMed1994

[Color Doppler flow data of breast tumors].

The recent development of high-quality colour Doppler instruments allows flow detection in small vessels below the resolution of B-mode imaging. Therefore, Doppler is now frequently used for flow detection in tumours. For breast examinations, CW Doppler has been in use for many years, which allows a sufficient definition of diagnostic criteria. Nevertheless, it is surprising that new studies using colour Doppler try to define different diagnostic criteria. To characterise the vascularity of breast lesions by colour Doppler we investigated 127 symptomatic patients. In 54 carcinomas the average flow velocity was 32 cm/s and 12.6 cm/s in 73 benign conditions (p > 0.0001). Total tumour vascularisation was characterised by a new parameter: the sum of all flow velocities in all tumour vessels. In carcinomas the mean total flow as 197.9 cm/s, and 52.7 cm/s in benign pathologies (p > 0.0001). Mean RI (resistance index) and PI (pulsatility index) were calculated to describe the flow profiles. The wide variation did not allow for a differentiation between benign and malignant lesions.

Arteries↗
PubMed1994

Expression of transcripts for CSF-1 and for the "macrophage" and "epithelial" isoforms of the CSF-1R transcripts in human ovarian carcinomas.

Levels of CSF-1 and CSF-1 receptor (CSF-1R) (fms) transcripts were quantified by Northern and dot blotting in total RNA extracts from 68 human ovarian carcinomas and positive and negative controls. Overall, very high levels of CSF-1 and CSF-1R transcripts were found in 11 and 21% of ovarian carcinoma specimens, respectively. When probes specific for CSF-1R exon1 were employed, which hybridize with the "epithelial" but not with the "hematopoietic" isoforms of the CSF-1R transcripts, the results suggested that both isoforms of the CSF-1R transcript were present in the tumor specimens. When levels of CSF-1 and CSF-1R were compared, a positive correlation was observed. Taken together, these results confirm prior observations of high levels of CSF-1 and CSF-1R in ovarian carcinoma specimens and that the latter include both "epithelial" and "macrophage" CSF-1R transcript isoforms, as might be expected for specimens composed of malignant epithelial cells and stromal macrophages.

Carcinoma↗
PubMed1993

Loss of constitutional heterozygosity on chromosome 11p in human ovarian cancer. Positive correlation with grade of differentiation.

BACKGROUND: There is increasing evidence suggesting that genes located on the short arm of chromosome 11 play an important role in the development of human ovarian cancer. Recent cytogenetic and molecular studies have demonstrated the loss of genetic material in this region. Loss of normal growth regulatory genes may allow for the expression of tumorigenicity or lead to tumor progression. METHODS: The authors used DNA recombinant techniques to examine the frequency of allelic losses at four loci spanning the chromosomal region 11p15.1-11p15.5 in 40 patients with malignant ovarian tumors. DNA extracts from normal leukocytes and 48 tumor samples were analyzed by Southern blotting using the polymorphic probes pEJ6.6 (HRAS1), phins310 (INS), p20.36 (PTH), and pEM36 (CALCA). RESULTS: Reduction to homozygosity in the tumor DNA was found in 47.5% of the informative cases (19 of 40). Comparing the results with clinical parameters, none of the well-differentiated tumors (6 of 40, Grade 1) and only one of the early stage tumors (6 of 40, International Federation of Gynecology and Obstetrics [FIGO] Stage I or II) showed alterations in this chromosome region. Statistical analysis revealed a strong correlation of rate of loss of constitutional heterozygosity (LOH) and grade of differentiation, in the sense of higher 11p allele losses occurring in poorly differentiated tumors. CONCLUSIONS: The authors concluded that the relatively high incidence of 11p allele losses marks an important step in ovarian cancer development. Furthermore, statistical analysis showed that loss of 11p alleles was strongly correlated with poorly differentiated ovarian cancer, indicating the location of genes involved in cellular functions associated with the development of more anaplastic tumors.

Adenocarcinoma↗
PubMed1993

Gene structure and expression analysis of the epidermal growth factor receptor, transforming growth factor-alpha, myc, jun, and metallothionein in human ovarian carcinomas. Classification of malignant phenotypes.

This study reports the structure and expression rates of genes of the transforming growth factor-alpha (TGF-alpha) signal transduction pathway (TGF-alpha, epidermal growth factor receptor [EGF-R], jun, myc, and metallothionein [MT]) in 47 specimens of ovarian cancer and 21 nonmalignant tissues. The objective was to establish a direct correlation between the genetic activities and the malignant phenotype of the ovarian cancer. The Southern blot technique identified four samples with myc amplification and two with rearranged EGF-R genes. By using the S1 nuclease assay, the analysis of myc transcription showed a similar use of both promotors. Although the size of the investigated transcripts was unaltered, significant differences in the transcription rates were noticed in malignant tissue probes (using northern blot analysis and RNAase protection assay). The following results of messenger RNA analysis in ovarian cancer were observed: EGF-R, negative in 25%, low in 65%, and strongly positive in 10%; TGF-alpha, negative in 34%, low in 36%, and strongly positive in 30%; myc, negative in 8%, low in 64%, and strongly positive in 28%; jun, negative in 4%, low in 58%, and strong in 38%; and MT, low in 80% and strongly positive in 20%. In most nonmalignant tissues studied, no or only a low expression of TGF-alpha, EGF-R, and myc. was found. A comparison of these messenger RNA results with the clinical data from tumors showed four different subgroups of ovarian carcinomas. The results of chemotherapy were known in 32 cases. Tumors with negative or low expression rates of all investigated genes did not respond to chemotherapy; 13 of 18 tumors with high expression rates did respond. Additional signal transduction chains distinct from the TGF-alpha pathway, however, are likely to influence both the expression and activity of transcription factors and MT.

Adult↗
PubMed1992

Cytogenetic analysis of an adenoid cystic carcinoma of the Bartholin's gland. A rare, semimalignant tumor of the female genitourinary tract.

Cytogenetic analysis has been performed on short-term cultures from a 56-year-old woman suffering from an adenoid cystic carcinoma of Bartholin's gland. Beside a normal female karyotype, the tumor revealed an abnormal cell line with complex chromosome changes involving the chromosomes 1, 4, 6, 11, 22, and 14. The mainly structural and nonbalanced rearrangements led to the loss of the chromosome segments 1p31----qter, 4q22----q28, 6p12----qter, 11p11.2----pter, 14q24----qter, and 22q13----qter. Clonal numerical aberrations were not observed. To our knowledge, such a tumor has to-date not been cytogenetically investigated.

Bartholin's Glands↗
PubMed1992

Identification of a negative regulatory domain in the human papillomavirus type 18 promoter: interaction with the transcriptional repressor YY1.

The human papillomavirus type 18 (HPV-18) promoter contains a TPA responsive element (TRE) which confers TPA responsiveness on a heterologous promoter. In the context of the HPV-18 promoter, however, this AP-1 site is inactive. We have identified a negative regulatory domain in the HPV-18 promoter which represses the constitutive and TPA-induced AP-1 activity. This negative regulatory sequence has been mapped to 44 nucleotides (OL13). We identified this element as a transcriptional silencer based on its ability to interfere with transcriptional initiation. This HPV-18 silencer domain was narrowed down further to 23 nucleotides, the OL13B element, which bears similarity to three other silencer sequences, present in the mouse N-ras gene upstream regulatory region, the mouse albumin gene enhancer and the adeno-associated virus P5 promoter. The transcriptional repressor protein YY1, which negatively regulates the P5 promoter, binds to the HPV-18 silencer with high affinity. Mutation of the YY1 binding site leads to an enhanced activity of the HPV-18 promoter, strongly suggesting that YY1 plays an important role in controlling HPV-18 early gene expression.

Base Sequence↗
PubMed1992

Epidermal growth factor receptor and transforming growth factor alpha expression in human ovarian carcinomas.

The varying tumorbiological behaviour of ovarian carcinomas probably influences operability, response to chemotherapy, being one of the most relevant prognostic factors. Because it is believed that an activation of the epidermal growth factor/transforming growth factor alpha (EGF/TGF alpha) signal pathway could be involved, we analysed the expression of epidermal growth factor receptor (EGFR) and TGF alpha with molecular-chemical, biochemical and immunohistochemical methods in 42 ovarian carcinomas, 4 ovarian metastasis, 2 other malignant ovarian tumours, and in 25 nonmalignant tissues (ovary, myometrium). No major rearrangements or amplification of the EGFR or TGF alpha genes were found. In non-malignant tissues no strong EGFR or TGF alpha signals were detected. TGF alpha is mainly produced by the tumour cells as shown by immunohistochemistry. Four different high molecular weight forms (20-48 kD) were detected in malignant tissues by western blot analysis.

Blotting, Northern↗
PubMed1992

Oncogene and growth factor expression in ovarian cancer.

The varying tumor-biological behavior of ovarian carcinomas probably influences both their operability and response to chemotherapy, which are the most relevant prognostic factors. The phenotype of different ovarian carcinomas is obviously associated with an activation of the EGF/TGF-alpha signal pathway, including c-myc and c-jun expression. Analysis of EGF-R, TGF-alpha, c-myc and c-jun expression in 33 stage III/IV, and 2 stage I/II ovarian carcinomas with biochemical, molecular-chemical and immunohistochemical methods showed a correlation between the mRNA and protein levels of EGF-R and TGF-alpha for tumors with low or high expressing rates. However, the concentration of measurable free EGF-Rs seems to depend on the amount of TGF-alpha expression by the tumors. The EGF-R binding ligand TGF-alpha is produced by epithelial tumor cells; stromal cells are usually TGF-alpha-negative, as shown by immunohistochemistry. High expression rates of EGF-R. TGF-alpha and c-myc were detected in 6, 7, and 10 out of 35 ovarian carcinomas, respectively. C-jun mRNA was detected in 18/19 cases studied. Non-malignant tissues originating from myometrium or ovary expressed no (or only small amounts of) EGF-R or TGF-alpha mRNA, whereas a high c-myc expression was found in 1/7 normal myometria, and in 2/5 normal ovaries. There was no strong correlation between EGF-R/TGF-alpha and c-myc/c-jun expression.(ABSTRACT TRUNCATED AT 250 WORDS)

Blotting, Northern↗
PubMed1991

Delineation of human papillomavirus type 18 enhancer binding proteins: the intracellular distribution of a novel octamer binding protein p92 is cell cycle regulated.

The enhancer of human papillomavirus type 18 consists of two functionally redundant domains, one is partially conserved between HPV18 and HPV16, both mediate strong transcriptional enhancement. In contrast, short fragments of the enhancer mediate low transcriptional enhancement, suggesting that there is functional cooperation between HPV enhancer binding factors. Previously interactions of the enhancer with NF-1, AP1 and steroid receptors were shown by EMSA. Here we show by binding site blotting, that four novel sequence specific proteins p110, p92, p42 and p40 bind to the enhancer. Nuclear proteins p110 and p92 bind at repeated sites in the enhancer, proteins p42 and p40 only at one site. Recognition sequences for p110 and p92 were identified in a TTGCTTGCATAA sequence motif and consist of an overlapping p110 and p92 recognition site. The specific interaction of p110 with G residues of this 12 nucleotide long sequence was demonstrated by a mutant recognition site. Single recognition sites for p42 and p40 were localized in the enhancer by the use of overlapping oligonucleotides. In addition, electrophoretic mobility shift analysis identified Oct-1 and AP2 interactions with the enhancer. The AP2 binding site was mapped to a AGGCACATATT motif. The p92 protein binds to enhancer oligonucleotides, containing at least one copy of Oct-1 like recognition sequences, these oligonucleotides also bind synthetic Oct-1 protein. During serum starvation or at high saturation density, p92 moves from the nucleus into the cytoplasm. Immunoblots of cytoplasmic extracts with anti-Oct-1 antisera showed, that p92 is a novel octamer binding factor, which is not immunologically related to the Oct-1 protein. The intracellular p92 distribution is regulated at the G0/G1 boundary of the cell cycle, by nucleo-cytoplasmic translocation.

Base Sequence↗
PubMed1991

Influence of chromosomal integration on glucocorticoid-regulated transcription of growth-stimulating papillomavirus genes E6 and E7 in cervical carcinoma cells.

In most cervical carcinoma cells the E6 and E7 genes of specific human papillomaviruses are transcribed from viral sequences integrated into host cell chromosomes. Glucocorticoids activate the promoter elements of various human papillomaviruses in transient-expression assays. We have analyzed the effect of dexamethasone on the transcription rate of human papillomavirus 18 E6 and E7 genes integrated at different chromosomal sites in four cervical cancer cell lines. Dexamethasone led to an increase in the transcription rate of the integrated E6-E7 sequences in C4-1 and C4-2 cells but led to a decrease in SW 756 cells and did not affect the transcription rate in HeLa cells. However, when the viral promoter elements derived from HeLa or SW 756 cells, in which dexamethasone does not activate transcription of the integrated E6-E7 sequences, were tested in transient-expression assays within the same cell lines, dexamethasone consistently activated the viral promoter. It thus appears that dominant regulatory mechanisms presumably depending on the chromosomal integration site are able to override the response of the viral promoter to steroid hormones. The growth rate of all dexamethasone-treated cell lines correlated consistently with the expression of the papillomavirus E6 and E7 genes, supporting their role in the maintenance of the proliferative phenotype of cervical carcinoma cells. Since human papillomaviruses are integrated into the host cell genome at variable, presumably randomly selected chromosomal loci, regulatory mechanisms that influence viral gene expression, and hence cell growth, may differ among cancers of independent clonal origin.

Cell Line↗
PubMed1991

Extinction of the HPV18 upstream regulatory region in cervical carcinoma cells after fusion with non-tumorigenic human keratinocytes under non-selective conditions.

'Universal fuser' clones of a human papillomavirus type 16 positive cervical carcinoma cell line (SiHa) were established to study the effect of a non-tumorigenic fusion partner on the regulation of a stably integrated chloramphenicol acetyltransferase (CAT) gene controlled by the HPV18 upstream regulatory region under non-selective conditions. The CAT expressing cells were fused with both non-tumorigenic, spontaneously immortalized human keratinocytes (HaCaT) and non-modified SiHa cells. The resulting hybrids were characterized by restriction enzyme fragment length polymorphism analysis and flow cytometry. While the non-selectable, HPV18-driven indicator gene is constitutively expressed in SiHa cells, the CAT activity is extinguished in SiHa x HaCaT cells, but still present in SiHa x SiHa hybrids. Examination of the cytokeratin expression pattern reveals that the keratinocyte phenotype seems not only to be dominant in terms of the extinction of the HPV18 regulatory region but also by the conservation of most of the differentiation markers of the non-tumorigenic fusion partner. Cycloheximide treatment and intracellular competition experiments using the transient COS7 fusion-amplification technique are accompanied by the reactivation of the marker gene in previously CAT- SiHa x HaCaT hybrids. These data strongly suggest that trans-acting negative regulatory factors derived from the non-malignant human keratinocytes are responsible for the extinction phenomenon.

Animals↗
PubMed1991

Plant biochemistry of xenobiotics: isolation and properties of soybean O- and N-glucosyl and O- and N-malonyltransferases for chlorinated phenols and anilines.

O-Glucosyltransferase (O-GT), O-malonyltransferase (O-MAT), N-glucosyltransferase (N-GT), and N-malonyltransferase (N-MAT) activities have been detected in cultured soybean cells, using pentachlorophenol and 3,4-dichloroaniline as xenobiotic standard substrates. The O-GT was purified approximately 1000-fold, and the N-MAT approximately 70-fold. There was an extensive copurification of O-GT and O-MAT. The following functional molecular weight values were obtained, 47 kDA (O-GT), 48 kDA (O-MAT) 43 kDa (N-GT), and 48 kDa (N-MAT). O-GT and N-MAT appeared to be monomeric polypeptides with isoelectric points of approximately 4.8 and approximately 6.1, respectively. The O-GT, N-GT, and N-MAT activities had marked substrate specificities for chlorinated aromatic xenobiotics and thus illustrate the existence of plant isoenzymes with specificity for xenobiotics.

Acyltransferases↗
PubMed1990

Clinical significance of oncogenes and growth factors in ovarian carcinomas.

The expression of epidermal growth factor receptor (EGF-R), transforming growth factor alpha (TGF alpha) and the c-myc oncogene was investigated in different specimens of gynecologic carcinomas. EGF specific binding sites were detected in about 50% of adenocarcinomas (ovarian, endometrial, breast) and in over 90% of squamous carcinomas (cervical). There is a positive correlation between the EGF-R binding assay, immunohistochemistry and the relative amounts of mRNA by Northern blotting. TGF alpha was investigated by immunohistochemistry and Northern blotting. TGF alpha immunoreactivity was detected exclusively in the epithelial cells of nonmalignant tissues (skin, cervix, endometrium, large bowel, lung) as well as different ovarian carcinomas. The TGF alpha immunostaining score correlates with the TGF alpha mRNA amounts. The c-myc expression was analyzed by Northern blotting in the specimens of ovarian carcinomas. Whereas, a positive correlation between the c-myc and TGF alpha expression was noticed, no correlation existed between EGF-R and c-myc expression. Progressive disease (PD) of ovarian carcinomas after chemotherapy was mainly noticed in the group of EGF-R- tumors and those with high amounts of c-myc mRNA. EGF-R+ ovarian carcinomas responded significantly better to chemotherapy. However, similar survival times existed between the EGF-R+ and EGF-R- group and the survival times of patients having responded to the treatment was reduced in the EGF-R+ group. This indicates that EGF-R+ and those carcinomas expressing high amounts of c-myc constitute a more aggressive group of ovarian carcinomas.

Adenocarcinoma↗
PubMed1990

In situ distribution of transforming growth factor alpha in normal human tissues and in malignant tumours of the ovary.

The distribution of transforming growth factor alpha (TGF-alpha) in human normal tissues from the uterus, Fallopian tube, ovary, small and large intestine, lung, spleen, kidney, and skin was studied by immunohistochemistry. TGF-alpha was found in epidermis, bronchial epithelium, intestinal mucosa, renal tubules, endo- as well as in exocervical and endometrial epithelium, and in the serous epithelium of the Fallopian tube. No TGF-alpha was detected in the stromal components of any of the tissues nor in any of the pre- and post-menopausal ovaries studied. Twenty-nine ovarian tumours including 23 ovarian carcinomas, one malignant mixed Mullerian tumour, two ovarian metastases of gastrointestinal carcinomas, one dysgerminoma, one sarcoma, and one fibroma were studied for TGF-alpha by the same immunohistochemical method. In 25 cases, specific cytoplasmic staining for TGF-alpha of epithelial tumour cells could be demonstrated. The pattern and intensity of the TGF-alpha immunostain varied among the TGF-alpha-positive tumours. No TGF-alpha was found by immunohistochemistry in the remaining four cases nor in the stromal tumour components of any of the lesions studied. Northern blot analysis for TGF-alpha mRNA was performed on 12 of the tumours. While the immunohistochemistry and blotting results correlated well in ten cases, discordant results were obtained in two lesions.

Blotting, Northern↗
PubMed1990

[Determination of epidermal growth factor (EGF) receptors in basal cell carcinomas, squamous cell carcinomas and melanomas].

We studied the binding of EGF receptors (EGF-R) in 19 basal cell carcinomas, 8 squamous cell carcinomas, and 9 malignant melanomas. Specific binding of EGF-R was detected in 10 of the basal cell carcinomas, and in all the 8 squamous cell carcinomas. None of the malignant melanomas showed EGF-R binding. A comparative study of the receptor status vs. clinical prognostic data, such as grading and clinical course, did not reveal any significant differences, whereas in ovarian carcinomas, the EGF receptor correlated with the prognosis.

Biomarkers, Tumor↗