Alzheimer Disease: Williams D

Karas GB, Burton EJ, Rombouts SA, van Schijndel RA, O'Brien JT, Scheltens P, McKeith IG, Williams D, Ballard C, Barkhof F. · Department of Diagnostic Radiology, Vrije Universiteit Medical Center, Amsterdam, The Netherlands. · Neuroimage. · Pubmed #12725765 No free full text.

Abstract: Voxel-based morphometry (VBM) has already been applied to MRI scans of patients with Alzheimer's disease (AD). The results of these studies demonstrated atrophy of the hippocampus, temporal pole, and insula, but did not describe any global brain changes or atrophy of deep cerebral structures. We propose an optimized VBM method, which accounts for these shortcomings. Additional processing steps are incorporated in the method, to ensure that the whole spectrum of brain atrophy is visualized. A local group template was created to avoid registration bias, morphological opening was performed to eliminate cerebrospinal fluid voxel misclassifications, and volume preserving modulation was used to correct for local volume changes. Group differences were assessed and thresholded at P < 0.05 (corrected). Our results confirm earlier findings, but additionally we demonstrate global cortical atrophy with sparing of the sensorimotor cortex, occipital poles, and cerebellum. Moreover, we show atrophy of the caudate head nuclei and medial thalami. Our findings are in full agreement with the established neuropathological descriptions, offering a comprehensive view of atrophy patterns in AD.

Wright CI, Dickerson BC, Feczko E, Negeira A, Williams D. · Laboratory of Aging and Emotion of the Psychiatric Neuroimaging Research Program, Massachusetts General Hospital, Harvard Medical School, Charlestown, Massachusetts 02129, USA. · Biol Psychiatry. · Pubmed #17336945 No free full text.

Abstract: BACKGROUND: Neuropsychiatric symptoms are very common even in mild stages of Alzheimer's disease (AD). The amygdala exhibits very early pathology in AD, but amygdala function in mild AD has received relatively little attention. The current study investigates functional alterations in the amygdala in aging and mild AD, and their relationships with neuropsychiatric symptoms. METHODS: Functional magnetic resonance imaging (fMRI) was used to examine and compare amygdala responses in 12 young and elderly controls and in 12 mild AD patients during viewing of neutral and emotional human facial expressions. RESULTS: Amygdala responses in the young and elderly did not significantly differ from each other. However, the AD group had significantly greater amygdala responses to both neutral and emotional faces relative to elderly controls. This group effect was maintained when amygdala volume, sex and age were included as covariates in the analysis. Furthermore, amygdala activity correlated with the severity of irritability and agitation symptoms in AD. CONCLUSIONS: The amygdala in patients with mild AD is excessively responsive to human faces relative to elderly controls. These amygdala functional alterations may represent a physiologic marker for certain neuropsychiatric manifestations of AD.

Taylor JP, Colloby SJ, McKeith IG, Burn DJ, Williams D, Patterson J, O'Brien JT. · Institute for Ageing and Health, Wolfson Research Centre, Newcastle General Hospital, Westgate Road, Newcastle upon Tyne NE4 6BE, UK. · J Neurol Neurosurg Psychiatry. · Pubmed #17299017 No free full text.

Abstract: BACKGROUND: 123I-labelled 2beta-carbomethoxy-3beta-(4-iodophenyl)-N-(3-fluoropropyl) nortropane (123I-FP-CIT) imaging is a diagnostic tool to help differentiate dementia with Lewy bodies (DLB) from Alzheimer's disease (AD). However, in animals, cholinesterase inhibitors (ChEi) have been reported to reduce radioligand binding to the striatal dopamine transporter. As ChEi are frequently used in people with dementia, it is important to determine whether their use affects 123I-FP-CIT uptake in the striatum. OBJECTIVE: To clarify whether chronic ChEi therapy modulates striatal dopamine transporter binding measured by 123I-FP-CIT in patients with AD, DLB and Parkinson's disease with dementia (PDD). DESIGN: Cross sectional study in 99 patients with AD (nine on ChEi, 25 not on ChEi), DLB (nine on ChEi, 19 not on ChEi) and PDD (six on ChEi, 31 not on ChEi) comparing 123I-FP-CIT striatal binding (caudate, anterior and posterior putamen) in patients receiving compared with those not receiving ChEi, correcting for key clinical variables including diagnosis, age, sex, Mini-Mental State Examination score, severity of parkinsonism and concurrent antidepressant use. RESULTS: As previously described, 123I-FP-CIT striatal uptake was lower in DLB and PDD subjects compared with those with AD. Median duration of ChEi use was 180 days. 123I-FP-CIT uptake was not significantly reduced in subjects receiving ChEi compared those not receiving ChEi (mean percentage reduction: AD 4.3%; DLB 0.7%; PDD 6.1%; p = 0.40). ChEi use did not differentially affect striatal 123FP-CIT uptake between patient groups (p = 0.83). CONCLUSIONS: Use of ChEi does not significantly influence the ability of 123I-FP-CIT imaging to distinguish AD from DLB.

Yang Q, Williams D, Owusu-Ababio G, Ebube NK, Habib MJ. · College of Pharmacy and Pharmaceutical Sciences, Florida A&M University, Tallahassee, USA. · Drug Deliv. · Pubmed #11400868 No free full text.

Abstract: Alzheimer's disease is a neurodegenerative condition that affects approximately 5 million people and is the fourth leading cause of death in America. Tacrine is one of the three drugs approved by the FDA for the treatment of Alzheimer's disease. However, the drug has a short biologic half-life of 2-3 hr and gastrointestinal, cholinergic, and hepatic adverse reactions that are associated with high doses of the drug. The aim of our study was to formulate a controlled release delivery system of tacrine that could be used to minimize the side effects associated with the drug. Microparticles of tacrine were formulated using poly(D,L-lactide-co-glycolide) (PLG). PLG and tacrine were dissolved in mixed organic solvents and added to a polyvinyl alcohol solution that was stirred at a constant rate. The organic solvent was evaporated overnight and the formed microparticles were collected by filtration, dried, and sieve-sized. The effects of such formulation variables, as molecular weight of polymer, stir speed during preparation, and drug loading on encapsulation efficiency (EEF), and in vitro release profiles of tacrine were investigated. An increase in the molecular weight of polymer from 8,000 to 59,000 and 155,000 resulted in approximately 10-fold increase in EEF, but the rate of release decreased with increasing molecular weight. Stir speed during preparation had an effect on the EEF but not on the rate of release. Drug loading did not have a significant effect on the EEF but had an effect on the rate of tacrine release. The results suggest that tacrine could be delivered at controlled levels for weeks for the treatment of Alzheimer's disease.