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Ca 2+ influx through the N-methyl-D-aspartate-type glutamate receptor leads to activation and postsynaptic accumulation of Ca 2+ / calmodulin-dependent protein kinase II. NRI and NR2B subunits of N-methyl-D-aspartate receptor serve as high-affinity Ca 2+ /calmodulin-dependent protein kinase II docking sites in dendritic spines on autophosphorylation of Ca 2+ /calmodulin-dependent protein kinase II. By comparative Western blot analysis, we show a reduction of NRI and phosphorylated Ca 2+ /calmodulin-dependent protein kinase II levels in the frontal cortex and hippocampus of Alzheimer's disease brains. We also found a significant correlation between phosphorylated Ca 2+ /calmodulin-dependent protein kinase II and NRI levels. Our study extends the view that N-methyl-D-aspartate receptor deficiency underlies memory impairment in Alzheimer's disease, and that this process likely involves insufficient activation of Ca 2+ /calmodulin-dependent protein kinase II.

Using tau protein extracts from Alzheimer's disease (AD) brain tissue, we generated a monoclonal antibody (mAb DC11) which decorated neurofibrillary pathology in brain derived from AD patients on immunohistochemistry, and which lacked reactivity with healthy brain tissue. The same pattern of DC11 specificity was observed on Western blot. The main constituent of structures decorated by DC11 is microtubule-associated protein tau. In Western blot, DC11 recognized neither native healthy tau nor its full length recombinant counterpart. However, the mAb showed strong immunoreactivity with truncated tau (residues tau151-421), thus indicating the requirement for a conformational epitope. Importantly, the DC11 epitope was phosphorylation independent. The immunochemical parameters of mAb show that DC11 could represent a novel structural probe with the specificity for conformation of pathological tau present in AD brains.

The amyloid cascade hypothesis suggests that amyloid precursor protein (APP) proteolytic processing is a key event in the pathogenesis of Alzheimer's disease (AD). The enzymes beta-site APP cleaving enzyme (BACE) and A disintegrin and metalloproteinase 10 (ADAM10) play an important role in APP proteolysis. We measured by real time quantitative polymerase chain reaction their mRNA levels in hippocampal and cerebellar sections from 13 AD and 12 control brains. BACE mRNA amounts were similar in patients and controls. In contrast, ADAM10 mRNA levels were twofold higher in AD samples, but without relationship to the severity of anatomical damage. The data do not support the hypothesis that alteration of BACE and ADAM10 expression are associated with development of late stages of AD.

Enzyme activities of the serine/threonine kinase Akt were compared in mid-temporal and mid-frontal cortices from Alzheimer's disease cases and matched controls. Activities (GSK-3alpha/beta fusion protein phosphorylation by immunoprecipitated Akt) were significantly increased in temporal cortex soluble fractions from Alzheimer's disease compared with non-disease controls and positive disease controls with another neurodegenerative disease. Temporal cortex soluble fraction Akt activities positively correlated with Braak staging for neurofibrillary changes. Frontal cortex soluble fraction activities were significantly reduced in positive disease compared with Alzheimer's disease cases and non-disease controls. Strong Ser Akt immunoreactivity was seen in Alzheimer's disease pyramidal neurons likely undergoing degeneration and in reactive astroglia. Non-disease and positive disease controls showed moderate Ser Akt immunostaining of occasional pyramidal neurons.

The aims of this study were to develop a rapid immuno- assay to determine the levels of ubiquitin in cerebrospinal fluid and to establish the ubiquitin levels in the spinal fluid of normal aged individuals. A competitive enzyme-linked immunoflow assay was developed. In this assay, ubiquitin is bound to nitrocellulose membrane, after which the primary antibody-test sample mixture and the enzyme- labeled secondary antibody under vacuum are applied sequentially. The final reaction product is collected in a microtiter plate by suction. This competitive assay requires only approximately 4 h and is potentially useful for determining in biological fluids the levels of any antigen or its antibodies that might be present. Employing this immunoassay, cerebrospinal fluid ubiquitin levels were found to be 147.5 ± 5.2 ng ml-1 in non-neurological aged cases.

The amyloid cascade hypothesis suggests that amyloid precursor protein (APP) proteolytic processing is a key event in the pathogenesis of Alzheimer's disease (AD). The enzymes beta-site APP cleaving enzyme (BACE) and A disintegrin and metalloproteinase 10 (ADAM10) play an important role in APP proteolysis. We measured by real time quantitative polymerase chain reaction their mRNA levels in hippocampal and cerebellar sections from 13 AD and 12 control brains. BACE mRNA amounts were similar in patients and controls. In contrast, ADAM10 mRNA levels were twofold higher in AD samples, but without relationship to the severity of anatomical damage. The data do not support the hypothesis that alteration of BACE and ADAM10 expression are associated with development of late stages of AD.