Biomedical subjects

B Brandt

Publications and source records attributed to B Brandt.

At least 19 recordsLinked to original sources

PubMed2006

Pitfalls in immunohistochemical assessment of EGFR expression in soft tissue sarcomas.

BACKGROUND: New targeted cancer treatments acting against growth factor receptors such as the epidermal growth factor receptor (EGFR) necessitate selecting patients for treatment with these drugs. Besides carcinomas, soft tissue sarcomas (STS) express EGFR and might thereby be a promising target for this new therapeutic strategy. OBJECTIVE: To test and compare different EGFR antibodies to determine the frequency of EGFR expression in STS. METHODS: 302 consecutive specimens of STS were examined using the tissue microarray technique. EGFR expression levels were assessed by immunohistochemistry using five different commercially available antibodies. Gene amplification status was measured by fluorescence in situ hybridisation (FISH). Immunoreactivity and amplification status were correlated with clinicopathological features and follow up data available in 163 cases. RESULTS: EGFR expression frequency ranged between 0.3% and 52.9%, depending on the antibody and scoring method used. In all, 3.5% of the tumours showed egfr gene amplification by FISH, which correlated with EGFR expression for three antibodies. Only one antibody had independent prognostic value in multivariate analysis and correlated with an unfavourable outcome; egfr gene amplification status showed no correlation with clinical features. CONCLUSIONS: Frequency of EGFR immunopositivity in STS strongly depends on the antibody used, and only one of five antibodies tested predicted an unfavourable clinical outcome. This indicates that choice of primary antibody and scoring system have a substantial impact on the determination of EGFR immunoreactivity.

Adolescent↗

PubMed2006

Whole genome expression analysis for biologic rational pathway modeling: application in cancer prognosis and therapy prediction.

Using semi-quantitative microarray technology, almost every one of the approximately 30 000 human genes can be analyzed simultaneously with a low rate of false-positives, a high specificity, and a high quantification accuracy. This is supported by data from comparative studies of microarrays and reverse-transcription PCR for established cancer genes including those for epidermal growth factor receptor (EGFR), human epidermal growth factor receptor-2 (HER2/ERBB2), estrogen receptor (ESR1), progesterone receptor (PGR), urokinase-type plasminogen activator (PLAU), and plasminogen activator inhibitor-1 (SERPINE1). As such, semi-quantitative expression data provide an almost completely comprehensive background of biological knowledge that can be applied to cancer diagnostics. In clinical terms, expression profiling may be able to provide significant information regarding (i) the identification of high-risk patients requiring aggressive chemotherapy; (ii) the pathway control of therapy predictive parameters (e.g. ESR1 and HER2); (iii) the discovery of targets for biologically rational therapeutics (e.g. capecitabine and trastuzumab); (iv) additional support for decisions about switching therapy; (v) target discovery; and (vi) the prediction of the course of new therapies in clinical trials. In conclusion, whole genome expression analysis might be able to determine important genes related to cancer progression and adjuvant chemotherapy resistance, especially in the context of new approaches involving primary systemic chemotherapy. In this review, we will survey the current progress in whole genome expression analyses for cancer prognosis and prediction. Special emphasis is given to the approach of combining biostatistical analysis of expression data with knowledge of biochemical and genetic pathways.

Cluster Analysis↗

PubMed2006

The response of the novel pro-inflammatory molecules S100A8/A9 to exercise.

Exercise shares many similarities with the acute phase response of inflammatory diseases. Recently, elevated serum levels of the novel pro-inflammatory molecules of the S100 protein family, S100A8 and S100A9, have been associated with various inflammatory diseases. The present study was conducted to assess their potential roles as inflammatory markers in monitoring the exercise-induced immune response. Seventeen male subjects of different training status performed a marathon run. Furthermore 13 subjects (10 male, 3 female) performed three different treadmill tests: strenuous (STE), moderate (MTE), and downhill (DTE). S100A8/A9 complexes were measured by ELISA, while white blood cell count (WBC) and C-reactive protein (CRP) were used as markers of the inflammatory response. Serum creatine kinase (CK) concentration was determined as a marker for muscle damage. After marathon S100A8/A9 increased dramatically during the early post-exercise period and returned to resting levels one day after the run. A similar pattern was found for WBC, while CK and CRP reached their maximum on the day after the run. Moreover, S100A8/A9 release was higher in the subgroup of well-trained athletes. The kinetic of the S100A8/A9 release after the treadmill tests depended on exercise intensity and was prolonged after eccentric exercise. In summary, the present results indicate that the novel pro-inflammatory molecules S100A8/A9 are very early and sensitive markers of the exercise-induced inflammatory response. Further investigations are necessary to evaluate the applicability of S100A8/A9 for monitoring the training process and to elucidate the dependence on training status.

Adult↗

PubMed2005

Catenin expression in T1/2 carcinomas of the floor of the mouth.

Reduction of the expression of catenin is a crucial step in the pathogenesis, progression and prognosis of many epithelial cancers including squamous cell carcinomas (SCCs). Catenin expression in oral carcinomas was evaluated in relation to clinico-pathological features in order to determine its value as a prognostic marker. Eighty-five patients with histologically proven T1/2 squamous cell carcinoma of the oral floor who underwent surgical treatment were eligible for the study. A tissue microarray consisting of multiple representative tissue cores of each carcinoma was composed. The expression levels of alpha, beta and gamma-catenins were determined immunohistologically. Correlation between clinical features and the expression of catenin proteins was evaluated statistically using Kaplan-Meier curves, log-rank tests and chi(2)-tests. Loss of alpha-catenin expression in carcinoma of the floor of the mouth correlated significantly with poor prognosis (P=0.05). Conversely, significantly reduced rates of lymph-node metastases were observed in alpha- and beta-catenin-positive T1 and T2 SCCs. Loss of gamma-catenin expression indicated a reduced survival rate in nodal-negative tumours (P=0.02). Catenin expression in carcinomas of the floor of the mouth seems to be a predictive parameter in the prognosis of T1 and T2 SSCs.

Adult↗

PubMed2005

CLL family 'Pedigree 14' revisited: 1947-2004.

The notion that inherited predisposition contributes to the development of haematological malignancies is generally thought of as being a relatively new idea. However, Videbaek made a clear enunciation of such a hypothesis in 1947, from a study of tumour incidence in relatives of patients with different leukaemias. To gain further insight into inherited susceptibility to chronic lymphocytic leukaemia (CLL), we followed up the descendants of Videbaek's 'Pedigree 14' series of families. Using the Danish medical and pedigree databases, complete tracing of 222 descendants of the original 57 family members was achieved. To date, 10 family members have been diagnosed with CLL, one with T-cell lymphoma and 17 with nonhaematological cancers, including five with breast cancer. The detailed follow up of this family provides further support for inherited predisposition to CLL and illustrates the value of follow-up studies of previously published family material for genetic analyses.

Aged↗

PubMed2005

Cytogenetic differences in breast cancer samples between German and Japanese patients.

BACKGROUND: Japanese and German breast cancer cases differ substantially in the frequency of egfr amplification. AIMS: To unravel further the cytogenetic differences between Japanese and German breast cancer cases. METHODS: Forty one Japanese breast cancer cases were evaluated by means of comparative genomic hybridisation (CGH). The results were compared with the CGH results from 161 German breast cancer cases. RESULTS: The mean number of genetic alterations/case was significantly higher in German premenopausal patients with breast cancer than in their Japanese counterparts. Japanese breast cancer cases revealed a higher number of chromosome 17p losses. Losses of 8p were associated with oestrogen receptor (ER) negativity in Japanese patients with breast cancer, whereas in the German patients gains of 3q and 6q were associated with the lack of ER expression. CONCLUSIONS: The interethnic differences of invasive breast cancer are reflected by cytogenetic aberrations, which are also associated with the differential expression of the ER.

Adult↗

PubMed2005

The diverse signaling network of EGFR, HER2, HER3 and HER4 tyrosine kinase receptors and the consequences for therapeutic approaches.

The HER family of receptor tyrosine kinase couples binding of extracellular growth factor ligands to intracellular signal transduction pathways, contributing in this fashion to the ability of the cell to respond correctly to its environment. The HER family and its ligands are critically involved in the carcinogenesis of the mammary gland. Abnormal function of the members of HER family resulting in receptor hyper-activation (due to gene amplification, protein overexpression or abnormal transcriptional regulation) has been linked with breast cancer prognosis. It is also extensively studied as the predictive factor and target for therapy. There are clinical indications supporting the concept that none of the receptors: EGFR, HER2, HER3 and HER4 can be considered as the stand-alone receptor in breast cancer development and clinical course of the disease. There is a growing body of evidence that cooperation between them contributes to more aggressive tumor phenotype and influences the response to therapy. This underlines the importance of quantification of all HER family members and indicates the urgent need for implementation of methods that can efficiently and reliably examine four HER receptors as a whole panel in breast cancer patients.

Animals↗

PubMed2005

Expression of early placenta insulin-like growth factor in breast cancer cells provides an autocrine loop that predominantly enhances invasiveness and motility.

Early placenta insulin-like growth factor (EPIL) is expressed by a subpopulation of the Her2-positive SKBR3 breast cancer cell line displaying high motility and transendothelial invasiveness in vitro, as recently shown by our group. As a consequence of this, we established cellular models by generating an EPIL-overexpressing SKBR3 cell line, knocked down EPIL by adding specific small interfering RNA (siRNA) to those cells and produced EPIL-enriched and depleted serum-free culture media. EPIL-expressing cells as well as EPIL-induced SKBR3 cells acquired a high capacity for transendothelial invasiveness. We observed a thin and outspread morphology caused by enhanced formation of lamellipodia, i.e. protrusions in the initial phase of motility. In parallel, Her2-positive MDAHer2 breast cancer cells also showed increased invasiveness when induced by EPIL-conditioned medium. A downstream signaling impact of EPIL could be observed in the form of reduced phosphorylation of Her2, erk1/2 and akt, while phospholipase Cgamma1 phophorylation remained unaffected. As an in vivo model for highly motile tumor cells, Paget's disease of the nipple showed simultaneous EPIL and Her2 expression upon immunohistochemical examination using specific antibodies. Such experimental data have been translated to a clinical setting by using a prognostic tissue microarray established from 603 breast cancer cases. Survival data analysis found a significant association between expression levels of EPIL and 5-year overall survival that was dose dependent: EPIL (negative) 84%, EPIL (moderately positive) 77%, EPIL (strongly positive) 48% (P < 0.005). One particular subgroup (7.6% of the cases with full clinical records) that comprised tumors simultaneously expressing EPIL and Her2 represented patients with the poorest 5-year overall survival. The results suggested that EPIL might be a cancer cell-produced growth factor that influences lateral Her2 signaling. Moreover, EPIL may be induced by factors apart from Her2 and may independently provide signaling for cancer invasion and motility.

Autocrine Communication↗

PubMed2004

Deciphering a subgroup of breast carcinomas with putative progression of grade during carcinogenesis revealed by comparative genomic hybridisation (CGH) and immunohistochemistry.

Distinct parallel cytogenetic pathways in breast carcinogenesis could be identified in recent years. Nevertheless, it remained unclear as to which tumours may have progressed in grade or which patterns of cytogenetic alteration may define the switch from an in situ towards an invasive lesion. In order to gain more detailed insights into cytogenetic mechanisms of the pathogenesis of breast cancer, the chromosomal imbalances of 206 invasive breast cancer cases were characterised by means of comparative genomic hybridisation (CGH). CGH data were subjected to hierarchical cluster analysis and the results were further compared with immunohistochemical findings on tissue arrays from the same breast cancer cases. The combined analysis of immunohistochemical and cytogenetic data provided evidence that carcinomas with gains of 7p, and to a lesser extent losses of 9q and gains of 5p, are a distinct subgroup within the spectrum of ductal invasive grade 3 breast carcinomas. These aberrations were associated with a high degree of cytogenetic instability (16.6 alterations per case on average), 16q-losses in over 70% of these cases, strong oestrogen receptor expression and absence of strong expression of p53, c-erbB2 and Ck 5. These characteristics provide strong support for the hypothesis that these tumours may develop through stages of well- and perhaps intermediately differentiated breast cancers. Our results therefore underline the existence of several parallel and also stepwise progression pathways towards breast cancer.

Breast Neoplasms↗

PubMed2004

Evaluation of an in situ setting injectable calcium phosphate as a new carrier material for gentamicin in the treatment of chronic osteomyelitis: studies in vitro and in vivo.

A study was performed to investigate the effectiveness of hydroxyapatite cement (HAC) as a new carrier system in the treatment of chronic, posttraumatic osteomyelitis. In the in vitro study, release of gentamicin from standard cylinders of HAC were measured by agar diffusion test. As a representative for mechanical properties, compression strength was measured in order to detect changes when mixing HAC with gentamicin. In the in vivo study, bone infection was induced according to the model of Norden by injection of 1 ml Na-morrhuat and 3 x 10(6)CFU Staphylococcus aureus. After 3 weeks, when chronic stage of infection was obtained, 17 animals were treated by debridement and filling the marrow either with HAC alone or HAC mixed with gentamicin (32 mg/g). Animals of the control groups were left untreated. After 6 weeks, all animals were sacrificed. Hematological, radiological, microbiological and histological examinations were carried out by covered investigation. Best evidence of the efficiency of treatment was observed in histopathological and microbiological findings. In all swabs of the control groups, taken 6 weeks following infection S. aureus were detected which were clonal to the strain used for induction of osteomyelitis. In HAC/gentamicin-treated animals, no growth was detectable after 7 days of culturing in BHI bouillon. In the HAC/gentamicin-treated group, there was no histopathological evidence of infection. In all other groups different stages of chronic osteomyelitis were found. No side effect was observed, neither locally nor systemically by HAC or gentamicin. Therefore, HAC is considered to be a very effective carrier for antibiotics in treatment of chronic, posttraumatic osteomyelitis.

Animals↗

PubMed2003

Investigations on the predictability of the formation of glassy solid solutions of drugs in sugar alcohols.

A prerequisite for the formation of glassy solid solutions prepared by the melting method is the miscibility of the respective drug and the carrier in the molten state. As could be shown experimentally, all investigated drug/sugar alcohol combinations miscible in the molten state form to some extent glassy solid solutions, dependent on their tendency to recrystallize during preparation. Therefore, the present study focuses on the evaluation of factors that govern the miscibility of molten drugs and sugar alcohols as carriers. In this context, solubility parameters are discussed as a means of predicting miscibility in comparison to a new approach, using calculated interaction parameters derived from molecular dynamics (MD) studies. There is evidence that a Coulomb interaction term C(SR), comprising short-range electrostatic interactions and hydrogen bonding energy is essential for the miscibility of drug and carrier in the molten state. To relate C(SR) to the molecular volume, a non-dimensional parameter P(i) is defined. For this parameter, a limiting value for miscibility exists. Contrary, calculated solubility parameter differences between drug and sugar alcohol in the range of 8-15 MPa(1/2) are not suitable for a prediction of miscibility or immiscibility, since the mixtures deviate from regular solution behavior. In irregular mixtures of drugs and sugar alcohols, an excess entropy and the formation of hydrogen bonds between unlike molecules favor miscibility, that cannot be predicted by regular solution theory.

Glass↗

PubMed2003

Cytology and image cytometry after colonic lavage: a complementary diagnostic tool in patients with ulcerative colitis.

BACKGROUND: Patients with extensive, long-standing ulcerative colitis have increased risk of colorectal cancer. AIMS: To improve the detection of high-risk patients, using a combination of colonic cytology, histology, and DNA image cytometry after segmental colonic lavage. PATIENTS: A series of 16 patients (8 high-risk patients) with ulcerative colitis were investigated. METHODS: After segmental lavage step, biopsies were obtained. Gradient centrifugation of the colonic fluid was performed for isolation and purification of epithelial cells. The smears and biopsy specimens obtained were stained for routine interpretation and for DNA image cytometry. RESULTS: Segmental lavage could be performed in all patients. Specimens from two high-risk patients showed low grade dysplasia and atypia by means of histology and cytology, respectively. In one patient, without increased colorectal cancer risk, atypia was detected. Three patients in the high-risk group, two of those diagnosed as positive for dysplasia and atypia, showed aneuploidy histologically and cytologically. DNA aneuploidy, in cytological material, was found exclusively in three low-risk patients, one of those had atypia cytologically. CONCLUSIONS: Isolation and purification of epithelial cells after segmental colonic lavage using density gradient centrifugation can be performed as part of routine endoscopy. It provides information about atypical cells and DNA aneuploidy as additional markers of malignant transformation. The combination of cytologic examination and DNA image cytometry might improve the detection of high-risk ulcerative colitis patients.

Adult↗

PubMed2003

Molecular cytogenetic investigations of synchronous bilateral breast cancer.

BACKGROUND: Bilaterality in breast cancer is a rare event and together with an early onset of disease points towards inheritance of the disease. However, most cases seem to occur sporadically, either in a synchronous or metachronous manner. METHODS: Thirty two invasive carcinomas and one in situ carcinoma from 16 patients with synchronous, bilateral breast cancer were investigated by means of comparative genomic hybridisation (CGH) and polymerase chain reaction based multiplex microsatellite analysis. The results were analysed conventionally and were also subjected to a biomathematical cluster analysis. RESULTS: On average, bilateral breast cancer cases showed a low number of genetic alterations, a low frequency of genetic amplifications, and a high rate of chromosomal 16q losses. A distinct, characteristic genetic alteration associated with bilateral breast disease could not be found. Although two tumour pairs appeared to be related using biomathematical processing for microsatellite analysis, this result was reproduced by CGH data processing in one patient only. CONCLUSIONS: Most synchronous, bilateral breast cancer cases seem to represent independent tumours rather than metastatic events. Nevertheless, the possibility of a specific susceptibility remains.

Adult↗

PubMed2002

A variable structure, less resource intensive modification of problem-based learning for pharmacology instruction to health science students.

A less resource intensive but more structured modification of problem-based learning was developed to teach pharmacology to pharmacy students in classes of 90 students. The method utilizes an active learning tool developed from cognitive science and cognitive learning theory. This case-based approach was developed to address the need to teach problem-solving skills to relatively large classes while conserving faculty and other resources. The method involves students working through cases in small groups according to a prescribed format. Groups are chosen at random to present the case to the whole class followed by open but structured discussion. Students bring recommended texts to class and groups are asked to answer questions relating to the material in the case, or to determine how the way their approach to the case would differ if patient parameters or medications in the case were altered utilizing the required texts. Each class begins with a short 1-min quiz on the fact-based material to be discussed that day and ends with a wrap-up of critical issues or principles learned. Continual probing of "what" and "why" characterizes each class meeting. Examinations are predominately open book and follow the same format as the in class cases. Learning outcomes for each general topic are provided at the beginning of the semester. Although the method does require students to learn pharmacology "facts", it places the facts within the context of application to practice. Rather than memorizing lists of side effects, for example, the format requires utilizing the side effects list and information about them to appropriately counsel the patient on how to deal with each and/or to suggest modifications in the therapy. Since implementing this method in an endocrine pharmacology course, student performance on problem-solving examinations has improved. Additionally, student evaluation of the method is extremely positive.

Adult↗

PubMed2001

Molecular dynamics simulations of stratum corneum lipid models: fatty acids and cholesterol.

We report the results of an investigation on stratum corneum lipids, which present the main barrier of the skin. Molecular dynamics simulations, thermal analysis and FTIR measurements were applied. The primary objective of this work was to study the effect of cholesterol on skin structure and dynamics. Two molecular models were constructed, a free fatty acid bilayer (stearic acid, palmitic acid) and a fatty acid/cholesterol mixture at a 1:1 molar ratio. Our simulations were performed at constant pressure and temperature on a nanosecond time scale. The resulting model structures were characterized by calculating surface areas per headgroup, conformational properties, atom densities and order parameters of the fatty acids. Analysis of the simulations indicates that the free fatty acid fraction of stratum corneum lipids stays in a highly ordered crystalline state at skin temperatures. The phase behavior is strongly influenced when cholesterol is added. Cholesterol smoothes the rigid phases of the fatty acids: the order of the hydrocarbon tails (mainly of the last eight bonds) is reduced, the area per molecule becomes larger, the fraction of trans dihedrals is lower and the hydrophobic thickness is reduced. The simulation results are in good agreement with our experimental data from FTIR analysis and NIR-FT Raman spectroscopy.

Body Temperature↗

PubMed2001

Flow cytometric DNA and phenotype analysis in pathology. A meeting report of a symposium at the annual conference of the German Society of Pathology, Kiel, Germany, 6-9 June 2000.

This meeting report summarizes the presentations of three different groups that are active in the field of flow cytometry (FCM) in relation to diagnosing and classification of proliferative disorders. The report starts with the contribution from Regensburg about the developments in DNA FCM, the progression to dual parameter determinations, and combination of immunophenotyping in combination with DNA. In the second part, the use of FCM for the detection of isolated tumor cells in the peripheral blood from patients with prostate or breast cancer is discussed in a contribution from Münster. In the third part, from Heerlen, the use of multi-parameter FCM on formalin-fixed paraffin-embedded tissues from solid tumors is discussed as a new development and application in routine surgical pathology.

DNA↗

PubMed2001

Structural and immunochemical characterization of the lipooligosaccharides expressed by Neisseria subflava 44.

Neisserial lipooligosaccharides (LOSs) are a family of complex cell surface glycolipids. We used mass spectrometry techniques (electrospray ionization, collision-induced dissociation, and multiple step), combined with fluorophore-assisted carbohydrate electrophoresis monosaccharide composition analysis, to determine the structure of the two low-molecular-mass LOS molecules (LOSI and LOSII) expressed by Neisseria subflava 44. We determined that LOSI contains one glucose on both the alpha and beta chains. LOSII is structurally related to LOSI and differs from it by the addition of a hexose (either glucose or galactose) on the alpha chain. LOSI and LOSII were able to bind monoclonal antibody (MAb) 25-1-LC1 when analyzed by Western blotting experiments. We used a set of genetically defined Neisseria gonorrhoeae mutants that expressed single defined LOS epitopes and a group of Neisseria meningitidis strains that expresses chemically defined LOS components to determine the structures recognized by MAb 25-1-LC1. We found that extensions onto the beta-chain glucose of LOSI block the recognition by this MAb, as does further elongation from the LOSII alpha chain. The LOSI structure was determined to be the minimum structure that is recognized by MAb 25-1-LC1.

Animals↗

PubMed2001

Genetic characterisation of invasive breast cancer: a comparison of CGH and PCR based multiplex microsatellite analysis.

AIMS: Comparative genomic hybridisation (CGH) is a reliable tool to gain an overview of all unbalanced chromosomal alterations within a tumour. Nevertheless, the high numbers of tumour cells required and the comparatively low resolution are drawbacks of this technique. Polymerase chain reaction (PCR) based multiplex microsatellite analysis represents a semi-automated, highly reproducible method, which requires small amounts of tumour cells. This is a comparative study of CGH and microsatellite analysis. METHODS: Eighty one samples of invasive breast cancer were investigated by two sensitive multiplex PCRs containing three microsatellites each of six markers (D6S261, D11S907, D6S300, D11S927, D8S272, and D11S925), and two additional microsatellite markers located within intron 1 of the epidermal growth factor receptor gene (egfr) and p53 (p53CA). RESULTS: At least one example of loss of heterozygosity was detectable in all breast cancer tissues. However, the overall rate of accordance between the two methods tested was only 61%. An increasing rate of the number of genetic alterations in each case was mirrored by a constantly increasing fractional allelic loss index. CONCLUSIONS: PCR based multiplex microsatellite analysis using this panel of eight microsatellite markers not only enables the characterisation of cells that have malignant potential in a high frequency of patients with breast cancer, but can also give an estimate of the degree of genetic progression.

Breast Neoplasms↗