Parke, Davis & Co. LLC

Early endosomes are a major site of amyloid precursor protein (APP) processing and a convergence point for molecules of pathologic relevance to Alzheimer's disease (AD). Neuronal endosome enlargement, reflecting altered endocytic function, is a disease-specific response that develops years before the earliest stage of AD and Down syndrome (DS). We examined how endocytic dysfunction is related to Abeta accumulation and distribution in early stage AD and DS. We found by ELISA and immunocytochemistry that the appearance of enlarged endosomes coincided with an initial rise in soluble Abeta40 and Abeta42 peptides, which preceded amyloid deposition. Double-immunofluorescence using numerous Abeta antibodies showed that intracellular Abeta localized principally to rab5-positive endosomes in neurons from AD brains and was prominent in enlarged endosomes. Abeta was not detectable in neurons from normal controls and was diminished after amyloid deposition in neuropathologically confirmed AD. These studies support growing evidence that endosomal pathology contributes significantly to Abeta overproduction and accumulation in sporadic AD and in AD associated with DS and may signify earlier disease-relevant disturbances of the signaling functions of endosomes.

This paper describes an approach to prevent HIV-cell fusion by disrupting the interaction between HIV protein gp120 and CD4 receptor. The CD4 residues Phe43 and Arg59 make important interactions with gp120. Small molecule analogues were made to mimic the crucial features of these residues. The analogues were assayed using a cellular 'FIGS' assay to measure inhibition of cell fusion and caused some inhibition.

A novel linker I for solid phase synthesis is described, which exhibits rapid cleavage under selective, orthogonal conditions, including stability under acidic conditions.Rapid cleavage of the product is effected by elimination of the silyl group on treatment with fluoride.Two systems of this type have been synthesized, and the stability of the linkers has been tested under acidic and basic conditions in solution