Biomedical subjects

Christina Dahl

Publications and source records attributed to Christina Dahl.

4 recordsLinked to original sources

PubMed2006

Methods for detection of subtle mutations in cancer genomes.

With the realization that cancer is a genetic disease, detection of mutations in genomic DNA has become an important discipline in many areas of cancer research. Although the publication of the human genome sequence and the immense technological advancements have facilitated the analysis of cancer genomes, detection of mutations in tumor specimens may still be challenging and fraught with technical problems. In this review, we describe current technologies for detection of small DNA mutations, including mutation scanning techniques to search for unknown mutations, and diagnostic techniques to detect known cancer mutations. We outline the principles of the different techniques and discuss their advantages and limitations. We also discuss critical issues that must be considered before choosing methodology, including sensitivity, specificity, limit of detection, throughput and cost, quantity and quality of template DNA, available equipment, and personnel expertise.

DNA Fingerprinting↗

PubMed2005

Identification of identical TCRs in primary melanoma lesions and tumor free corresponding sentinel lymph nodes.

It is generally believed that priming of efficient T-cell responses takes place in peripheral lymphoid tissues. Although this notion has been rigidly proven for infectious diseases, direct evidence for lymph node priming of in vivo T-cell responses against tumors is still lacking. In the present study, we conducted a full and nonbiased comparison of T-cell clonotypes in melanoma lesions and corresponding sentinel lymph nodes. Whereas most tumor lesions comprised a high number of T-cell clonotypes, only a small number of clonally expanded T cells were detected in the draining lymph nodes. Comparative clonotype mapping demonstrated the presence of identical T-cell clonotypes in the tumors and the respective sentinel lymph nodes, only when tumor cells were present in the latter. However, taking advantage of clonotype specific PCR amplification, TCR sequences representing clonally expanded T cells at the tumor site could be detected in the lymph nodes draining the tumors even in the absence of tumor cells. Evidence for the tumor-specific characteristics of these cells was obtained by in situ staining with peptide/HLA class I complexes demonstrating the presence of MART-1/HLA-A2- and MAGE-3/HLA-A2-reactive T cells at the tumor site, as well as in the draining lymph node. Our data indicate that T-cell responses to melanoma are primed in the sentinel lymph node by cross presentation of tumor antigens by dendritic cells.

Adult↗

PubMed2004

Fluoro-modified chemotactic peptides: fMLF analogues.

A small library of peptide analogues of the chemotactic tripeptide For-Met-Leu-Phe-NH2 modified by substitution of Leu at position 2 by three different fluorinated amino acids varying in content of fluorine, length of the fluorinated side chain, and alkylation degree at the alpha-carbon atom was synthesized. The influence of the fluorine substitution on the biological activity was investigated by measuring the oxidative activity of neutrophils using a luminol-dependent chemiluminescence assay.

Chemotaxis↗

PubMed2003

DNA methylation analysis techniques.

DNA methylation contributes to the control of gene expression and plays an essential role in cellular physiology. Well-defined patterns of DNA methylation are established and fixed during embryonic development, and changes in these patterns may be a contributing factor in developmental disorders, cancer and aging. Not least the possibility of using DNA methylation as a marker for disease has created a strong need for techniques to detect and measure DNA methylation. Different techniques provide information on DNA methylation at different levels, spanning from genome-wide methylation content to methylation of single residues in specific genes. The limitations of individual techniques strongly affect interpretation of data. In this review, we discuss some general themes in DNA methylation analysis and outline the basic principles of current key techniques. We discuss the advantages and disadvantages of these techniques, including potential artifacts and pitfalls, and suggest some overall guidelines that may be instructive for a rational choice of methodology.

Blotting, Southern↗