Biomechanical study of atlantoaxial arthrodesis: transarticular screw fixation versus modified Brooks posterior wiring.

Objective: The purpose of the present study was to compare the biomechanical stability of C1 and C2 vertebrae after treatment of ligamentous instability by either modified Brooks posterior wiring (MB) or transarticular screw (TAS) techniques. We hypothesized that the TAS technique would be more stable because of direct fixation through the facet joints.

Study Design: We studied the in vitro stability (arthrodesis) of TAS fixation of C1 and C2 versus that of MB.

Influence of APOE genotype on familial aggregation of AD in an urban population.

Objective: To examine the influence of the proband's APOE genotype on AD among first-degree relatives in a community-based study of African Americans, whites, and Caribbean Hispanics.

Methods: History of AD and demographic information were obtained on 1,073 siblings and parents of 312 patients with AD and 2,722 siblings and parents of 802 nondemented controls. APOE genotyping was performed on all 1,114 patients and controls.

Plasma amyloid beta-peptide 1-42 and incipient Alzheimer's disease.

Mutations in the amyloid precursor protein and presenilin 1 and 2 genes result in elevated plasma levels of the amyloid beta-peptide species terminating at amino acid residue 42 (A beta1-42). In a longitudinal study of unrelated elderly individuals, those who subsequently developed Alzheimer's disease had higher plasma levels of A beta1-42 at entry than did those who remained free of dementia. The results indicate that elevated plasma levels of the released A beta peptide A beta1-42 may be detected several years before the onset of symptoms, supporting that extracellular A beta1-42 plays an important role in the pathogenesis of late-onset Alzheimer's disease.

APOE genotype, plasma lipids, lipoproteins, and AD in community elderly.

Background: Genetic variation at the APOE locus has a major influence on both plasma lipid levels and the risk of AD. The relationship between APOE genotype and plasma lipids may influence the risk of AD.

Objective: In a community-based study of white, African American, and Caribbean Hispanic elderly in New York City, we investigated the relationship between plasma lipids and AD as well as the possible influence of APOE genotype on this relationship.

Low-density lipoprotein cholesterol and the risk of dementia with stroke.

Context: Next to Alzheimer disease, vascular dementia is the second most common form of dementia in the elderly, yet few specific risk factors have been identified.

Objective: To investigate the relationship of plasma lipids and lipoproteins to dementia with stroke.

Design And Setting: Prospective longitudinal community-based study over a 7-year period (1991-1998).

Rates of dementia in three ethnoracial groups.

Background: Rates of dementia may vary among ethnoracial groups. Any real and substantial such difference would merit serious attention by health planners, clinicians and those seeking to advance our understanding of the etiology of this group of disorders.

Methods: Randomly selected elderly persons from each of three ethnoracial groups (Latinos, African-Americans, non-Latino Whites) residing in a geographic area of northern Manhattan in New York City were screened for dementia and assessed with respect to functioning in daily tasks and other qualities of life.

The influence of smoking on the risk of Alzheimer's disease.

Objective: To investigate the relationship between cigarette smoking and Alzheimer's disease (AD) in a prospective community-based study in northern Manhattan.

Background: Results from previous case-control studies suggest that there is a protective effect of smoking on AD. However, the recent prospective Rotterdam Study found that there was an increased risk of AD for smokers, particularly those without an apolipoprotein E (APOE)-epsilon4 allele.

Selective decline in memory function among healthy elderly.

Objective: To use longitudinally acquired data to establish whether aging is associated with memory decline.

Background: Memory loss is one of the most frequent complaints among the elderly. Nevertheless, age-related memory decline remains controversial in large part because it has been established with cross-sectional studies.

Differential regional dysfunction of the hippocampal formation among elderly with memory decline and Alzheimer's disease.

The hippocampal formation is composed of separate anatomical regions interconnected to form a circuit, and investigating abnormal hippocampal function is most revealing at the level of these regions. Until recently, regional analysis of the hippocampal formation could be performed only in animals or in human postmortem tissue. Here, we report a method using functional magnetic resonance imaging that evaluates the hippocampal regions in vivo, and we use this method to study elderly with normal memory, with isolated memory decline, and with probable Alzheimer's disease (AD).

Risk of Alzheimer's disease in relatives of Parkinson's disease patients with and without dementia.

Objective: To determine whether first-degree relatives of PD patients with dementia were at increased risk for the development of AD compared with first-degree relatives of nondemented PD patients and nondemented normal subjects from the community.

Methods: A structured family history interview was administered to 146 nondemented PD patients, 120 patients with PD and dementia, and 903 normal subjects from the community to ascertain the presence of AD among parents and siblings of these subjects. Cox proportional hazards models with double censoring techniques for missing information were used to model the risk of AD among relatives.

Parkinson disease in twins: an etiologic study.

Context: The cause of Parkinson disease (PD) is unknown. Genetic linkages have been identified in families with PD, but whether most PD is inherited has not been determined.

Objective: To assess genetic inheritance of PD by studying monozygotic (MZ) and dizygotic (DZ) twin pairs.

A common Hpa I RFLP of apolipoprotein C-I increases gene transcription and exhibits an ethnically distinct pattern of linkage disequilibrium with the alleles of apolipoprotein E.

Apolipoprotein (apo) C-I is a constituent of triglyceride-rich lipoproteins (TGRL) that interferes with their hepatic clearance. Functional polymorphism in the apoC-I gene has not been established. We determined that an Hpa I site variably present at -317 relative to the apoC-I gene is produced by a 4-bp CGTT insertion.

A randomized, placebo-controlled dose-comparison trial of haloperidol for psychosis and disruptive behaviors in Alzheimer's disease.

Objective: The goal of this study was to compare the efficacy and side effects of two doses of haloperidol and placebo in the treatment of psychosis and disruptive behaviors in patients with Alzheimer's disease.

Method: In a 6-week random-assignment, double-blind, placebo-controlled trial (phase A), haloperidol, 2-3 mg/day (standard dose), and haloperidol, 0.50-0.

Characterization of the human mitochondrial aconitase gene (ACO2).

We have cloned and characterized the ACO2 gene on human chromosome 22q13, which encodes the essential iron-dependent metabolic enzyme mitochondrial aconitase. We determined that the ACO2 gene comprises 18 translated exons distributed over approximately 35 kilobasepairs (kbp) of DNA. We have shown that the ACO2 mRNA is 2.

Dietary iron, animal fats, and risk of Parkinson's disease.

Background: Recent studies have proposed a role for diet in Parkinson's disease (PD). PD is characterized by a high deposition of iron and a low concentration of ferritin in the substantia nigra. Few data in the literature are available on the possible role of dietary iron in the development of PD.

Validity of family history for the diagnosis of dementia among siblings of patients with late-onset Alzheimer's disease.

We examined 180 siblings of 127 probands with probable or possible Alzheimer's dementia (AD) in a family study of AD. The overall sensitivity of a simple family history questionnaire was 64% and the specificity was 84%. Sensitivity improved 90-100% with minimal decline in specificity when we considered clinic-based vs.

Postmenopausal estrogen use and Parkinson's disease with and without dementia.

We investigated the effects of estrogen replacement therapy (ERT) on the risk of development of dementia in 87 women with Parkinson's disease without dementia (PDND), 80 women with Parkinson's disease with dementia (PDD), and 989 nondemented healthy women from the same community. ERT was protective for the development of dementia within the setting of PD (OR 0.22, 95% CI 0.

Systemic iron metabolism and mortality from Parkinson's disease.

Six measures of systemic iron metabolism were used to predict mortality among 103 patients with Parkinson's disease and 353 controls followed in a longitudinal study. Adjusting for gender, education, ethnicity, presence of dementia, and extrapyramidal signs, transferrin receptor concentration was strongly associated with mortality in patients with PD but not controls. This increase in serum transferrin receptor concentration before death suggests that the previously observed perturbation in iron metabolism continues throughout the disease course.

Earlier onset of Alzheimer's disease in men with Down syndrome.

Background: Virtually all individuals with Down syndrome (DS) have neuropathologic changes characteristic of Alzheimer's disease (AD) beginning at 40 years of age. Few studies have examined factors that influence age at onset of AD in DS. We investigated whether sex differences in age at onset and risk of AD among adults with DS are similar to those observed in the general population and whether the effect of sex on risk of AD is modified by apolipoprotein E (APOE) genotype.

The APOE-epsilon4 allele and the risk of Alzheimer disease among African Americans, whites, and Hispanics.

Context: Although the association between Alzheimer disease (AD) and the apolipoprotein E epsilon4 (APOE-epsilon4) allele has been confirmed worldwide, it appears to be inconsistent among African Americans, Hispanics, and Nigerians.

Objective: To investigate the association between the APOE-epsilon4 allele and AD in elderly African Americans, Hispanics, and whites.

Design: Prospective, population-based, longitudinal study over a 5-year period (1991-1996).

Cognitive function in nondemented older women who took estrogen after menopause.

Investigations of the effects of estrogen replacement on cognitive function in healthy older women have yielded disparate results. We evaluated the relationship between a history of estrogen use and cognitive test performance in 727 women participating in a large community-based study. Participants were followed longitudinally for an average of 2.

Utility of the apolipoprotein E genotype in the diagnosis of Alzheimer's disease. Alzheimer's Disease Centers Consortium on Apolipoprotein E and Alzheimer's Disease.

Background: The epsilon4 allele of the gene encoding apolipoprotein E (APOE) is strongly associated with Alzheimer's disease, but its value in the diagnosis remains uncertain.

Methods: We reviewed clinical diagnoses and diagnoses obtained at autopsy in 2188 patients referred to 1 of 26 Alzheimer's disease centers for evaluation of dementia. The sensitivity and specificity of the clinical diagnosis or the presence of an APOE epsilon4 allele were calculated, with pathologically confirmed Alzheimer's disease used as the standard.