Search

Differential normalized fluorescence (DNF) is an efficient and effective method for the differentiation of normal and cancerous tissue fluorescence spectra. The diagnostic features are extracted from the difference between the averaged cancerous and averaged normal tissue spectra and used as indices in tissue classification. In this paper, a new method, probability-based DNF bivariate analysis, is introduced based on the univariate DNF method. Two differentiation features are used concurrently in the new method to achieve better classification accuracy. The probability of each sample belonging to a disease state is determined with Bayes decision theory. This probability approach classifies the tissue spectra according to disease states and provides uncertainty information on classification. With a data set of 57 colonic tissue sites, probability-based DNF bivariate analysis is demonstrated to improve the accuracy of cancer diagnosis. The bivariate DNF analysis only requires the collection of a few data points across the entire emission spectrum and has the potential of improving data acquisition speed in tissue imaging.

The exact duplication of a genome once per cell division is required of every proliferating cell. To achieve this goal, eukaryotes adopt a strategy that limits every replication origin to a single initiation event within a narrow window of the cell cycle by temporally separating the assembly of the pre-replication complex (pre-RC) from the initiation of DNA synthesis. A key component of the pre-RC is the hexameric MCM complex, which is also the presumed helicase of the growing forks. An elaborate mechanism recruits the MCM complex to replication origins, and a regulatory chain reaction converts the poised, but inactive, MCM complex into an enzymatically active helicase. A growing list of proteins, including Mcm10 and Cdt1, are involved in the recruitment process. Two protein kinases, the Cdc7-Dbf4 kinase (DDK) and the cyclin-dependent kinase (CDK), trigger a chain reaction that results in the phosphorylation of the MCM complex and finally in the initiation of DNA synthesis. A composite picture from recent studies suggests that DDK is recruited to the pre-RC during G1 phase but must wait until S phase to phosphorylate the MCM complex. CDK is required for the recruitment of Cdc45 and other downstream components of the elongation machinery.