2,4-dinitrophenol as an activating reagent in a facile preparation of cyclic phosphate trimesters

Abstract 2,4-Dinitrophenol was employed with benzyloxy-bis-(diisopropylamino)phosphine to synthesise the cyclic phosphate derivatives of a series of alkane diols (HO–(CH2)n–OH, n=2–6) in good isolated yields. Tetrazole and DNP were compared by 31P NMR spectroscopy for their ability to catalyse the cyclisation at the P(III) stage. Investigation of the phosphate triester stability under various oxidation and chromatographic conditions resulted in the optimisation of the isolation procedures of the chemically unstable cyclic compounds. Conditions for debenzylation were developed to yield the corresponding cyclic phosphodiesters quantitatively. The methodology was further applied to the preparation and isolation of the cyclic phosphate derivative of a carbohydrate.

Apoptosis and cell-cycle regulatory proteins in colorectal carcinoma: relationship to tumour stage and patient survival

The quantitative assessment of apoptotic index (AI) and mitotic index (MI) and the immunoreactivity of p53, bcl-2, p21, and mdm2 were examined in tumour and adjacent normal tissue samples from 30 patients with colonic and 22 with rectal adenocarcinoma. Individual features and combined profiles were correlated with clinicopathological parameters and patient survival data to assess their prognostic value. Increased AI was significantly associated with increased bcl-2 expression (p

Characterisation of two calmodulin-like proteins from the liver fluke, Fasciola hepatica.

Calmodulin is a calcium ion-sensing signalling protein found in eukaryotics. Two calmodulin-like gene sequences were identified in an EST library from adult liver flukes. One codes for a protein (FhCaM1) homologous to mammalian calmodulins (98% identity), whereas the other protein (FhCaM2) has only 41% identity. These genes were cloned into expression vectors and the recombinant proteins were expressed in Escherichia coli. Gel shift assays showed that both proteins bind to calcium, magnesium and zinc ions. Homology models have been built for both proteins. As expected, FhCaM1 has a highly similar structure to other calmodulins. Although FhCaM2 has a similar fold, its surface charge is higher than FhCaM1. One of the potential metal ion-binding sites has lower metal-ion co-ordination capability, while another has an adjacent lysine residue, both of which may decrease the metal-binding affinity. These differences may reflect a specialised role for FhCaM2 in the liver fluke.