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C Schneeberger

Publications and source records attributed to C Schneeberger.

48 records · Page 3Linked to original sources
PubMed1993

Rapid quantitative analysis of differential PCR products by high-performance liquid chromatography.

We describe the use of high-performance liquid chromatography (HPLC) for the rapid quantitative analysis of short DNA fragments generated in differential PCR, where a target gene and a control gene are in vitro coamplified in one single reaction. Using an anion-exchange nonporous column, both separation and quantitation of the differential PCR products are achieved in about 5 min per sample. The performance of this technique proved to be superior to that of conventional gel electrophoresis and subsequent analysis by a laser densitometer, a solid-state scanner and a charge coupled device video camera imaging system. The usefulness for clinical testing is described in the example of the quantitative analysis of the c-erbB-2 oncogene copy number of human breast carcinomas by differential PCR. The combined use of differential PCR and automated HPLC analysis of the PCR products may well substitute for classical Southern blot hybridization in routine clinical analysis of oncogene amplification.

Base Sequence↗
PubMed1993

A simple method for isolation of DNA from blood clots suited for use in PCR.

We describe a rapid, simple and inexpensive method for the isolation of DNA from blood clots suited for use in PCR. Our method is based on the lysing and nuclease-inactivating properties of guanidine thiocyanate together with the nucleic acid-binding properties of silica particles. Isolated DNA can be used for in vitro amplification as shown for a retinoblastoma gene PCR system.

Base Sequence↗
PubMed1992

[Epidermal growth factor receptor in human breast cancer: correlation with steroid receptors, tumor stage, grading and menopausal status].

In this study, correlations between the epidermal growth factor receptor (EGF-R), steroid receptors, and other prognostic parameters (grading, pTNM-status, menopausal status) were analysed in 326 primary breast carcinomas. 19% of the tumour samples were EGF-R positive, 63% were estrogen receptor (ER) and 54% progesteron receptor (PR) positive. Both steroid receptors were positive in 46% of all samples. We found a highly significant inverse correlation between EGF-R and steroid receptors. 88% of the ER positive tumours were EGF-R negative (p less than 5 x 10(-5)), 90% of the PR positive tumours were EGF-R negative (p less than 5 x 10(-5)) and 91% of the ER plus PR positive tumours were ERF-R negative (p less than 1 x 10(-6)). Grading was available in 170 cases. Six (4%) of the carcinomas were highly differentiated (G1), 82 (48%) were classified as G2, and another 82 (48%) were poorly differentiated (G3). A combination of negative ER and positive EGF-R was found more often in the population of G3 tumours. EGF-R was also positively correlated to tumour size. With regard to receptor status, we did not find a correlation with lymph node involvement. The ER correlated negatively (p less than 1.3 x 10(-5) and the EGF-R positively (p less than 0.042) with menopausal status. Thus, EGF-R overexpression seems to be a marker of morphological and functional dedifferentiation which is associated with a loss of steroid dependency and an increase of an autostimulatory-paracrine growth control. These changes seem to be related to poor prognosis.

Breast↗
PubMed1990

Determination of HER-2/neu amplification and expression in tumor tissue and cultured cells using a simple, phenol free method for nucleic acid isolation.

A rapid, simple and non-toxic procedure for the simultaneous isolation of DNA and RNA from tumor tissue and cells grown in vitro is described. Guanidinium isothiocyanate was used for homogenization of tumor tissue and for cell lysis. Separation of proteins, DNA and RNA was carried out by isopycnic centrifugation in cesium trifluoroacetate. DNA was further purified by salting out residual protein. Nucleic acids prepared by this method from 47 primary human carcinomas and 17 human cell lines were analysed for amplification and expression of the HER-2/neu proto-oncogene. 2- to 10-fold amplification of HER-2/neu was noted in 7/22 mammary carcinomas (32%) and in 4/14 ovarian carcinomas (28%). No amplification of the proto-oncogene was found in 4 laryngeal carcinomas, 1 pharyngeal carcinoma, 2 retrolingual carcinomas, 3 gastric carcinomas and 1 kidney carcinoma. HER-2/neu overexpression was observed in 6/22 of mammary carcinomas (27%) and 7/14 of ovarian carcinomas (50%). No overexpression was found in all other carcinomas studied. Concordance between amplification and overexpression was noted in 3 mammary and 4 ovarian carcinomas, respectively. 3 mammary and 3 ovarian carcinomas showed overexpression without amplification. 5 human mammary carcinoma cell lines showed both amplification and overexpression of HER-2/neu. In two mammary carcinoma cell lines (MDA MB-453 and ZR 75-1) overexpression was noted without amplification of the proto-oncogene. These data combine to suggest that mechanisms other than gene amplification may also lead to overexpression of the HER-2/neu protooncogene in cancer cells.

Blotting, Southern↗
PubMed1979

[Blood culture].

Explore the source record for details and available documents.

Bacteriological Techniques↗
PubMedDate not supplied

Estrogen does not induce the calcium-dependent nitric oxide synthase in cultured human uterine endothelial and myometrial smooth muscle cells.

In many tissues, estrogen-induced vasodilatation is mediated, at least in part, by the release of nitric oxide (NO). We determined whether human myometrial endothelial and smooth muscle cells express estrogen receptors (ERs) and whether endothelial NO synthase (eNOS) expression in these cells was affected by 17beta-estradiol (10[-13]-10[-6]M). ER was strongly expressed in myometrial smooth muscle cells but was absent from endothelial cells. Expression of eNOS mRNA was strong in endothelial cells, but weak in muscle cells. 17beta-estradiol administration for 24 or 72 h failed to increase eNOS in both cell types. Thus, an increase of human uterine blood flow by estrogens appears not to be mediated by stimulation of myometrial eNOS expression.

Adult↗
PubMedDate not supplied

Cathepsin D and PAI-1 expression in human head and neck cancer.

In order to determine possible overexpression of cathepsin D and PAI-1 (plasminogen activator inhibitor) in head and neck tumours, cytosols from 92 primary squamous cell carcinomas (SCC), 19 lymph node metastases and 24 adjacent normal tissue samples were examined. For both cathepsin D and PAI-1, significantly elevated concentrations in SCC compared to normal tissue were found, even in pairwise comparison. Moreover, significantly higher cathepsin D and PAI-1 concentration in lymph node metastases than in corresponding normal tissue were also present. The conclusion was drawn that cathepsin D and PAI-1 may play a specific role in the biology of head and neck SCC.

Carcinoma, Squamous Cell↗
PubMedDate not supplied

Microdissection as a means to verify allelic imbalance in tumour biology samples.

Allelotypes (TP53, AFM051xd10 and alu-i1) in normal DNA and in DNA from paraffin-embedded tumours of a patient with a p53 germ-line mutation were compared in order to demonstrate LOH. Microdissection was applied in order to overcome difficulties with the interpretation of LOH data from a pelvic recurrence of a primary malignant histiocytoma. Furthermore, a rapid and simple boiling method was developed in order to reduce the loss of DNA usually occurring during traditional methods for DNA extraction. The conclusion drawn is that it is of utmost importance to use highly enriched fractions of tumour cells when performing LOH-studies. It is also shown that a rapid and simple boiling procedure is sufficient to release enough DNA of microdissection-enriched tumour cells for microsatellite analysis by PCR to detect allelic imbalance.

Alleles↗
PubMedDate not supplied

Competitive reverse transcriptase-PCR: an improved method for determination of c-erbB-2 gene expression.

The aim of our study was to establish a simple method for routine analysis of c-erbB-2 gene expression in tumour samples. We constructed a plasmid for the in vitro synthesis of competitor RNA to be used as an internal exogenous control during the RT-PCR detection of c-erbB-2 expression. The competitor RNA harbors a 19-base deletion and 63-base insertion compared to wild-type c-erbB-2 mRNA and generates a PCR product which is easily distinguished from the wild-type PCR product by agarose gel electrophoresis. The sensitivity and reliability of our RT-PCR-system was determined. To address this, we measured c-erbB-2 expression in cultured cells, of which c-erbB-2 expression data were available from Northern blot analysis. In conclusion, our experimental strategy correlated well with the results obtained by Northern blot hybridization, however, it overcomes time consuming and expensive procedures used in classical gene expression analysis.

Base Sequence↗