Differential scanning calorimetry of gliomas: a new tool in brain cancer diagnostics?

Background: Thermal stability signatures of complex molecular interactions in biological fluids can be measured using differential scanning calorimetry (DSC). Evaluating the thermal stability of plasma proteomes offers a method of producing a disease-specific "signature" (thermogram) in neoplastic and autoimmune diseases.

Objective: The authors describe the use of DSC with human brain tumor tissue to create unique thermograms for correlation with histological tumor classification.

Preliminary use of differential scanning calorimetry of cerebrospinal fluid for the diagnosis of glioblastoma multiforme.

Thermal stability signatures of complex molecule interaction in biological fluids can be measured using a new approach called differential scanning calorimetry (DSC). The thermal stability of plasma proteome has been described previously as a method of producing a disease-specific "signature," termed thermogram, in several neoplastic and autoimmune diseases. We describe the preliminary use of DSC performed on cerebrospinal fluid (CSF) as a diagnostic tool for the identification of patients with glioblastoma multiforme (GBM).

The paradox of multiplex DNA melting on a surface.

Under equilibrium conditions, there are two regimes of target capture on a surface--target limited and probe limited. In the probe limited regime, the melting curve from multiplex target dissociation from the surface exhibits a single transition due to a reverse displacement mechanism of the low affinity species. The melting curve cannot be used in analytical methods to resolve heteroduplexes; only with the simplex system can proper thermodynamics be obtained.

Direct DNA methylation profiling using methyl binding domain proteins.

Methylation of DNA is responsible for gene silencing by establishing heterochromatin structure that represses transcription, and studies have shown that cytosine methylation of CpG islands in promoter regions acts as a precursor to early cancer development. The naturally occurring methyl binding domain (MBD) proteins from mammals are known to bind to the methylated CpG dinucleotide (mCpG) and subsequently recruit other chromatin-modifying proteins to suppress transcription. Conventional methods of detection for methylated DNA involve bisulfite treatment or immunoprecipitation prior to performing an assay.

Microarray temperature optimization using hybridization kinetics.

In any microarray hybridization experiment, there are contributions at each probe spot due to the match and numerous mismatch target species (i.e., cross-hybridizations).

Real-time DNA microarrays: reality check.

DNA microarrays are plagued with inconsistent quantifications and false-positive results. Using established mechanisms of surface reactions, we argue that these problems are inherent to the current technology. In particular, the problem of multiplex non-equilibrium reactions cannot be resolved within the framework of the existing paradigm.

Competitive displacement: a sensitive and selective method for the detection of unlabeled molecules.

We propose a new method for molecular detection that retains the sensitivity of fluorescence, but without requiring fluorescence labeling of the sample. The method works by spiking the sample solution with one or more labeled molecular species of known concentration. With proper choice of these "competitor" species, their binding kinetics can be used to quantitatively determine the concentration of unlabeled target species.