Biomedical subjects

Andrea Bauer

Publications and source records attributed to Andrea Bauer.

14 recordsLinked to original sources

PubMed2005

Specialized DNA arrays for the differentiation of pancreatic tumors.

PURPOSE: Malignant tumors of the pancreas are frequently indistinguishable from inflammatory tumors arising in the context of a chronic pancreatitis with the use of conventional imaging techniques. Thus, cytologic analysis of cells obtained by abdominal ultrasound, computed tomography, or endoscopic ultrasound-guided fine needle aspiration biopsy is required for diagnosis. However, the reliability of cytologic analyses of pancreatic fine needle aspirates remains unsatisfactory, with a diagnostic accuracy of < or =80%. The purpose of the current study was therefore to develop a novel diagnostic approach based on expression profiling of biopsy material using a specialized diagnostic cDNA array. EXPERIMENTAL DESIGN: Previous gene expression profiling studies were reevaluated to design a 558-feature diagnostic array. Minimal amounts of residual material from pancreatic cytology samples as well as surgically resected tumor and control tissue specimens were analyzed using the diagnostic array and a newly developed statistical classification system. RESULTS AND CONCLUSIONS: Our diagnostic approach resulted in 95% accurate differentiation between ductal adenocarcinomas and nonmalignant tumors of the pancreas. The diagnostic array, in conjunction with conventional diagnostic procedures, is thus suitable to significantly improve the reliability of pancreatic cancer diagnostics and can be expected to become a valuable new tool in the routine workup of suspect masses in the pancreas.

Adenocarcinoma↗

PubMed2005

Integration of GO annotations in Correspondence Analysis: facilitating the interpretation of microarray data.

MOTIVATION: The functional interpretation of microarray datasets still represents a time-consuming and challenging task. Up to now functional categories that are relevant for one or more experimental context(s) have been commonly extracted from a set of regulated genes and presented in long lists. RESULTS: To facilitate interpretation, we integrated Gene Ontology (GO) annotations into Correspondence Analysis to display genes, experimental conditions and gene-annotations in a single plot. The position of the annotations in these plots can be directly used for the functional interpretation of clusters of genes or experimental conditions without the need for comparing long lists of annotations. Correspondence Analysis is not limited in the number of experimental conditions that can be compared simultaneously, allowing an easy identification of characterizing annotations even in complex experimental settings. Due to the rapidly increasing amount of annotation data available, we apply an annotation filter. Hereby the number of displayed annotations can be significantly reduced to a set of descriptive ones, further enhancing the interpretability of the plot. We validated the method on transcription data from Saccharomyces cerevisiae and human pancreatic adenocarcinomas. AVAILABILITY: The M-CHiPS software is accessible for collaborators at http://www.mchips.org

Algorithms↗

PubMed2005

Contact dermatitis to quinoline, corticosteroids and antibiotics after short time treatment of delayed wound healing following malignant melanoma excision in a young woman.

BACKGROUND: We describe a 20-year old woman with retarded healing after a melanoma excision. After short time application of several creams containing antiseptic, antibiotic and anti-inflammatory ingredients she developed a severe contact dermatitis. Patch testing revealed sensitizations against corticosteroids, an antibiotic and quinoline. CONCLUSION: In our case multiple relevant contact sensitizations appeared within a short period of two months after excision of a malignant tumour.

Adult↗

PubMed2004

DNA microarray analysis of pancreatic malignancies.

Pancreatic ductal adenocarcinoma (PDAC) has an extremely poor prognosis. To improve the prognosis, novel molecular markers and targets for earlier diagnosis and adjuvant and/or neoadjuvant treatment are needed. Recent advances in human genome research and high-throughput molecular technologies make it possible to cope with the molecular complexity of malignant tumors. With DNA array technology, mRNA expression levels of thousand of genes can be measured simultaneously in a single assay. As several studies using microarrays in PDAC have already been published, this review attempts to compare the published data and therefore to validate the results. In addition, the applied techniques are discussed in the context of pancreatic malignancies.

Adenocarcinoma↗

PubMed2004

Tumor recurrence and survival in patients treated for thymomas and thymic squamous cell carcinomas: a retrospective analysis.

PURPOSE: Thymic epithelial tumors (TET) are rare epithelial neoplasms of the thymus with considerable histologic heterogeneity. This retrospective study focused on the correlation of WHO-defined TET histotypes with survival and tumor recurrence in a large cohort of patients receiving different modes of treatment. PATIENTS AND METHODS: Two hundred twenty-eight patients were followed for up to 21 years (median, 60 months; range, 1 to 252 months) after primary surgery. Forty-two patients received adjuvant radiotherapy (mean dose, 53 Gy), and 33 patients received adjuvant chemotherapy. RESULTS: Seventy-six (88%) of 86 patients with WHO type A, AB, and B1 thymomas were treated by surgery alone, with three tumor relapses after 3 to 10 years (median, 3.4 years). Twelve of 67 patients with WHO type B2 and B3 thymomas in Masaoka stages I and II were treated by adjuvant radiotherapy without evidence of tumor recurrence after 1 to 12 years (median, 4 years). Among 75 patients with B2 and B3 thymomas with incomplete resection or a tumor stage III or higher, the recurrence rate was 34% (n = 23) after 0.5 to 17 years (median, 5 years) in patients receiving adjuvant radiochemotherapy, compared to 78% (seven of nine patients) in patients without adjuvant radiochemotherapy. Incomplete tumor resection was associated with a high recurrence rate (65%) and a poor prognosis (P <.01). CONCLUSION: The long-term outcome of TET patients is related to tumor stage, WHO histotype, completeness of surgical removal, and type of treatment. Prospective trials are warranted to formally address the efficacy of adjuvant therapy in the treatment of localized and advanced malignant TETs.

Carcinoma, Squamous Cell↗

PubMed2004

Microcystic tubulopapillary carcinoma of the pancreas: a new tumor entity?

An unusual pancreatic tumor with microcystic and tubulopapillary features was observed in a 53-year-old woman. The tumor presented as a large, focally cystic mass in the head of the pancreas, which compressed the surrounding structures. The histological and immunohistochemical analysis revealed a neoplasm that could not be assigned to any of the known pancreatic tumor types. At the molecular level, the tumor showed inactivation of the DPC4/SMAD4 gene, deletion of exon 1 of the p16(INK4A) gene and a point mutation at codon 34 (GGA>AGA) of beta-catenin. Transcriptional profiling analyses and subsequent correspondence cluster analysis demonstrated that the transcriptional profile of the tumor differed distinctly from that of ductal adenocarcinomas, pancreatic cystic tumors and normal pancreatic tissues. These data suggest that the neoplasm most likely represents a new pancreatic tumor entity, which we would like to refer to as microcystic tubulopapillary tumor.

Adenocarcinoma↗

PubMed2004

Fluorescent sample labeling for DNA microarray analyses.

Three fluorophor-labeling methods for gene expression profiling on deoxyribonucleic acid (DNA) microarrays are described. All three techniques start from total ribonucleic acid (RNA) samples. Two procedures are based on first-strand complementary DNA synthesis by reverse transcription. Label is introduced either by direct incorporation of fluorescently labeled nucleotides or indirectly by incorporation of aminoally-dUTP and subsequent coupling of fluorescent dyes. The third method is based on an amplification of antisense RNA by in vitro transcription subsequent to first- and second-strand complementary DNA synthesis. While the first two methods are applied mainly in analyses on microarrays made from spotted polymerase chain reaction products or long oligonucleotides, the last procedure is mostly used for experiments on in situ synthesized oligonucleotide arrays.

DNA, Complementary↗

PubMed2004

Interleukin-5, interleukin-3 and granulocyte-macrophage colony-stimulating factor prime actin-polymerization in human eosinophils: a study with hypodense and normodense eosinophils from patients with atopic dermatitis.

Characteristic features of atopic diseases (AD) are immigration and local activation of eosinophils. Reorganization of the cytoskeleton modulates the function of leukocytes and is a prerequisite for the motility response. In this work, the regulation of actin polymerization has been investigated by flow cytometry using NBD-phallacidin and right angle light scatter measurements in purified eosinophils isolated from patients with atopic dermatitis and normal individuals. Stimulation of eosinophils with chemotaxins such as complement fragment C5a (C5a), CC chemokine RANTES/ CCL5 and platelet activating factor (PAF) induced a reversible polymerization of actin. Normodense eosinophils purified from patients with AD showed a decreased chemotaxin-induced actin response as compared to normodense eosinophils from healthy subjects and hypodense eosinophils from patients. Stimulation of eosinophils with Th2-cytokines such as interleukin-3 (IL-3), interleukin-5 (IL-5), granulocyte-macrophage colony-stimulating factor (GM-CSF) did not exert a significant effect on actin polymerization. However, pretreatment with IL-3, IL-5 or GM-CSF potentiated the chemotaxin-induced actin polymerization and graded the differential responsiveness between normodense and hypodense eosinophils. We demonstrate a different actin responsiveness in eosinophils from atopic patients and healthy subjects which could be overcome by modulating effects of Th2-cytokines.

Actins↗

PubMed2002

Paraneoplastic myasthenia gravis correlates with generation of mature naive CD4(+) T cells in thymomas.

Myasthenia gravis (MG) is the leading paraneoplastic manifestation of thymomas and is probably related to the capacity of thymomas to mature and export potentially autoreactive T cells. Why some thymomas are MG associated (MG+) and others are not (MG-) has been unclear. We addressed this question by comparing the percentages of intratumorous naive mature CD45RA+ thymocytes in 9 MG(+) and in 13 MG(-) thymomas by fluorescence-activated cell sorting analysis. Our results show that intratumorous naive CD4 T cells were present in all MG(+) thymomas and in one MG(-) thymoma with the development of MG only 2 months after surgery. By contrast, the percentage of naive CD4(+) T cells was significantly reduced in all 13 MG(-) thymomas (P <.0001). Alterations in intratumorous thymopoiesis were reflected by corresponding alterations of naive T-cell subset composition in the blood, in that only MG(-) patients had significantly decreased levels (P =.02) of naive CD4(+) T cells compared with age- and sex-matched control persons. We conclude that paraneoplastic MG is highly associated with the efficiency of thymomas to produce and export naive CD4(+) T cells. The acquisition of the CD45RA(+) phenotype on CD4(+) T cells during terminal intratumorous thymopoiesis is associated with the presence of MG in most thymoma patients.

Adult↗

PubMed2002

Prevention of hand dermatitis in bakers' apprentices: different efficacy of skin protection measures and UVB hardening.

OBJECTIVE: The objective of this controlled intervention study was to quantify the efficacy of skin protection (SP) measures and ultraviolet B (UVB) hardening in the prevention of hand dermatitis in bakers' apprentices. METHOD: SP measures were compared against UVB hardening in a controlled clinical trial of 94 apprentices. The apprentices were assigned to the intervention arms class-wise. Bakers' apprentices involved in a previous follow-up study served as additional controls representing no intervention. The apprentices were interviewed and examined in a standardised way at the beginning of the training and at 4 monthly follow-ups. Transepidermal water loss (TEWL) was measured at the back of the hands. RESULTS: Demographic profile and atopy criteria were equally distributed in the two intervention arms and the control group. Point prevalence of hand dermatitis after 6 months was highest in the controls (29.1%) followed by the UVB (19.4%) and the SP group (13.3%). UVB hardening and SP measures reduced hand dermatitis prevalence by 9.7% (95%CI: -8.5 to 28.1) and 15.7% (95%CI: -2.4 to 33.9), respectively. Application of SP measures reduced the odds ratios (ORs) for hand dermatitis 0.8-fold (95%CI: 0.17-3.70) and 0.33-fold (95%CI: 0.09-1.23) compared with the UVB group and the controls, respectively. These clinical trends were confirmed by statistically significant differences in TEWL values. TEWL values were consistently higher in the UVB group than in the SP group ( P=0.002). CONCLUSIONS: This study provided evidence, based on significant differences in TEWL levels, that general SP measures may be more effective than UV light hardening of the skin, which in turn was more effective than no intervention. This trend was supported by the frequency of development of clinical hand dermatitis, although differences did not reach statistical significance. A multi-centre trial is recommended to confirm the efficacy of SP measures in a larger randomised study.

Adolescent↗

PubMed2002

Skin protection in bakers' apprentices.

Skin protection measures - barrier creams, protective gloves - and skin care are widely recommended for the prevention of occupational hand dermatitis (HD) in skin risk professions, but there is hardly anything known about uptake levels of the measures. The objective of this controlled intervention study was to quantify the uptake and maintenance of skin protection and skin care measures in first-year bakers' apprentices. A total of 94 first-year bakers' apprentices were included in the study in September 2000. The apprentices were assigned to the skin protection and control group class-wise to reduce contamination. The skin protection group comprised 39 apprentices who were trained in skin protection measures at the beginning and after 4 weeks of training. 55 apprentices were assigned to the control group representing no skin protection intervention. Standardized interviews took place at the beginning of the training and at 4 monthly follow-ups (FU). The uptake of skin protection measures differed significantly between the groups (barrier cream p < 0.0001, protective gloves p = 0.046, skin care p = 0.025). Barrier cream use in the skin protection group was incorporated in the daily routine very well from the start and reached 100% at the end of the examination period (4th FU). At this time, only 3.2% of the controls used barrier creams. The level of acceptance of protective gloves (4th FU: skin protection group 43.3%; controls 32.3%) was considerably lower than that of barrier creams. The initial level of regular skin care was high in both groups (skin protection group 67.6%, controls 61.7%). After the intervention the acceptance of skin care rose to 88.9% in the skin protection group compared to 68.1% in the controls (4th FU). The present study has shown that skin protection and skin care measures can be introduced successfully in the daily routine of a skin risk occupation and high uptake and maintenance rates can be achieved.

Adolescent↗

PubMed2002

Type IV allergy in the food processing industry: sensitization profiles in bakers, cooks and butchers.

Data about the impact of allergic contact dermatitis in food processing occupations are scarce. The objective of this study was to identify the most frequent allergens and sensitization profiles in employees of the food processing industry. The results of patch testing performed in 873 bakers, cooks and butchers suspected of having occupational allergic contact dermatitis from 33 dermatological departments of the Information Network of Departments of Dermatology (IVDK) from 1992 to 1999 were analysed. A final diagnosis of allergic contact dermatitis was made in 213 patients (24.4%). Qualitative and quantitative differences in allergen profiles could be identified. Significantly higher sensitization rates were found in employees in the food processing industry, compared to the total test population, for nickel sulphate (22.4% versus 17.2%, p < 0.0005), thiuram mix (4.9% versus 2.6%, p < 0.0005), formaldehyde (3.5% versus 2.1%, p < 0.005) and Compositae mix (6.2%, p < 0.0005). Significantly lower sensitization rates were found for thimerosal (4.5% versus 6.9%, p < 0.05). For patch testing in food workers, we recommend the standard, the rubber and the Compositae series, as well as patients' own products according to the individual history.

Adult↗

PubMed2002

Patch tests with thiurams at 0.25% pet. and 1% pet. are of equal diagnostic value.

Thiuram mix is tested in the standard series at a test concentration of 1% pet. The single thiurams (DPTD, TMTD, TMTM, TETD), however, are usually tested at 0.25% pet. in Germany. In other countries, the individual components of thiuram mix are tested at 1% pet. The German Contact Dermatitis Research Group (DKG) compared both patch test concentrations in 530 patients in order to find out if (i) a significant number of positive patch tests are missed by testing at the lower concentration, (ii) problems with irritant test reactions occur by increasing the test concentration to 1%, and (iii) the sensitivity of the thiuram mix rises when the breakdown test is done with the higher concentration. Slightly more positive reactions were seen with the higher concentration, but this increase did not reach statistical significance. The reaction index, as a measure for the relation of positive to irritant and/or questionable reactions, remained unchanged for the individual thiurams. The sensitivity of the mix also did not change when the breakdown test was performed with 1% pet. instead of 0.25% pet. Thus, we conclude that both concentrations are of equal diagnostic value in patch testing.

Dermatitis, Allergic Contact↗

PubMedDate not supplied

Hand dermatitis: uncommon presentations.

Hand dermatitis is a common diagnosis seen in dermatologic and general practice. It can present with typical morphology, but uncommon manifestations are possible. This review reports on common and uncommon presentations of irritant and allergic hand dermatitis focusing on uncommon localizations, time course, and morphology such as follicular, pustular, bullous, ulcerous, exudative erythema multiforme-like, purpuric, lichenoid, pigmented, and depigmented skin lesions. Clinical diagnosis can be challenging. Even histopathology is not always very helpful. Thorough evaluation of the patient's history and investigation of clinical morphology are the cornerstones of diagnosis.

Dermatitis, Allergic Contact↗