Nanoparticle formation from poly(acrylic acid) and oppositely charged peptides.

Cationic peptides self assemble upon interacting with sodium salt of oppositely charged polymer, poly(acrylic acid), PAA, giving rise to water-soluble nanoparticles at very low concentration (0.1 mM of PAA). The morphology of these kinds of nanoparticles is mainly governed by the composition of the complexes, which can be expressed as Z+/-, i.

Imaging and analysis of Bacillus anthracis spore germination.

External and internal changes occurring during the process of germination of Bacillus anthracis spores were observed through atomic force microscopy (AFM) and transmission electron microscopy (TEM), respectively. AFM studies showed that in response to L-alanine (4 mM), as a germinant, the spore germinates into a vegetative cell in 3 hours. The temporal size changes occurring during the germination were gradual but the major change in size was observed between the second and third hour.

Complex formation between cationically modified gold nanoparticles and DNA: an atomic force microscopic study.

Atomic force microscopy has been used for direct visualization of the wrapping of DNA around 30-nm-sized functionalized gold nanoparticles for the first time. The morphology of the complexes seems to be dictated by the relative concentration of the nanoparticles and DNA. A higher concentration of the former leads to the formation of a network of nanoparticles assembled on DNA.

Alzheimer disease and mortality: a 15-year epidemiological study.

Background: Alzheimer disease (AD) is considered a leading cause of death, but few studies have examined the contribution of AD to mortality based on follow-up of representative US cohorts.

Objective: To examine mortality rates, duration of survival, causes of death, and the contribution of AD to the risk of mortality in an aging community-based cohort, controlling for other predictors.

Design: Fifteen-year prospective epidemiological study.

Complexes of poly(ethylene glycol)-based cationic random copolymer and calf thymus DNA: a complete biophysical characterization.

Complete biophysical characterization of complexes (polyplexes) of cationic polymers and DNA is needed to understand the mechanism underlying nonviral therapeutic gene transfer. In this article, we propose a new series of synthesized random cationic polymers (RCPs) from methoxy poly(ethylene glycol) monomethacrylate (MePEGMA) and (3-(methacryloylamino)propyl)trimethylammonium chloride with different mole ratios (32:68, 11:89, and 6:94) which could be used as a model system to address and answer the basic questions relating to the mechanism of the interaction of calf thymus DNA (CT-DNA) and cationic polymers. The solubility of the complexes of CT-DNA and RCP was followed by turbidity measurements.

Gambling participation and social support among older adults: a longitudinal community study.

The purpose of this preliminary study was to examine associations between leaving home to engage in bingo or gambling activity and indices of physical and mental health and social support among a representative community cohort of 1016 elderly people. Cross-sectional and longitudinal data gathered from a prospective epidemiological study in a rural, low socio-economic status, area of Pennsylvania was employed. The cohort had a mean age of 78.

Detection and management of cognitive impairment in primary care: The Steel Valley Seniors Survey.

Objectives: To identify characteristics of older primary care patients who were cognitively impaired and who underwent mental status testing by their physicians.

Design: Cross-sectional and retrospective analysis.

Setting: Seven small-town primary care practices.

Hemoglobin levels and Alzheimer disease: an epidemiologic study in India.

Objective: Anemia is common in developing countries, where populations are aging rapidly. The authors explored the cross-sectional relationship between hemoglobin concentration and Alzheimer disease (AD) in a rural elderly sample in Ballabgarh, India.

Methods: A clinical diagnostic evaluation for dementia and a hemoglobin estimation were performed in 605 persons selected by screening a larger community-based sample age 55+ years.

Exercise level and cognitive decline: the MoVIES project.

Growing evidence suggests that physical exercise may be protective against cognitive impairment and decline. A prospective study of a representative rural community sample (N = 1,146) aged 65+ years examined self-reported exercise habits and measured global cognitive function using the Mini-Mental State Examination (MMSE). A composite variable "exercise level" combining type, frequency, and duration of exercise was created with three levels: "high exercise" (aerobic exercise of > or = 30 minute duration > or = 3 times a week), "low exercise" (all other exercise groups), and "no exercise.

Mild cognitive impairment, amnestic type: an epidemiologic study.

Objective: To estimate the prevalence and examine the course of mild cognitive impairment (MCI), amnestic type, using current criteria, within a representative community sample.

Methods: Retroactive application of MCI criteria to data collected during a prospective epidemiologic study was performed. The subjects were drawn from voter registration lists, composing a cohort of 1,248 individuals with mean age of 74.

Depression after stroke: a prospective epidemiological study.

Objectives: To elucidate the relationship between stroke and depressive symptoms and to determine whether disability or cerebrovascular risk factors mediate that relationship.

Design: A prospective longitudinal epidemiological survey.

Setting: The mid-Monongahela Valley, a rural, nonfarm, low-socioeconomic-status community.

Medical and cognitive correlates of denture wearing in older community-dwelling adults.

Objectives: To examine the association between denture wearing and use of dental services, oral function limitations, and medical and cognitive status in a community-based cohort of rural older adults enrolled in an epidemiological study.

Design: This cross-sectional study was part of a larger cohort study, the Monongahela Valley Independent Elders Survey. Dental data were collected during the fifth wave of assessments (10 years after the start of the study in 1987).

Predictors of nursing facility admission: a 12-year epidemiological study in the United States.

Objectives: To identify predictors of institutionalization in a community-based cohort of older adults.

Design: Prospective, longitudinal. After initial assessment at study entry, surviving participants were reassessed in a series of approximately biennial waves until October 2001; baseline for the current analysis was Wave 2 (1989-91).

Nanoparticles from cationic copolymer and DNA that are soluble and stable in common organic solvents.

DNA by virtue of its superlative ability to self-assemble has found use beyond biological research in the design and fabrication of nanomaterials. However, developing novel DNA-based materials for chemical applications might be restricted due to the insoluble nature of DNA in most common organic solvents. In this Communication, we are reporting the first demonstration of making DNA soluble in a variety of nonbiological solvents such as acetonitrile, benzene, dimethyl sulfoxide (DMSO), and tetrahydrofuran with the help of poly(ethylene glycol) (PEG)-based cationic random copolymers.

The Mini-Cog as a screen for dementia: validation in a population-based sample.

Objectives: To test the Mini-Cog, a brief cognitive screening test, in an epidemiological study of dementia in older Americans.

Design: A population-based post hoc examination of the sensitivity and specificity of the Mini-Cog for detecting dementia in an existing data set.

Setting: The Monongahela Valley in Western Pennsylvania.

Blood pressure and cognitive impairment in India and the United States: a cross-national epidemiological study.

Objective: To evaluate the relationship between blood pressure (BP) and cognitive impairment in elderly populations in India and the United States in a cross-national epidemiological study.

Design: Cross-sectional comparisons, using standardized cognitive screening and BP measurements.

Participants: We examined 4810 subjects 55 years and older, of whom 595 were 75 years and older, from Ballabgarh, India, and 636 subjects 75 years and older from the Monongahela Valley, Pennsylvania.

Tracking cognitive functioning over time: ten-year longitudinal data from a community-based study.

Over 10 years, a community-based sample age 65> or = years, with a starting cohort size of 1,206, was assessed biennially with the Mini-Mental State Exam; the Consortium to Establish a Registry for Alzheimer's Disease battery; Immediate and Delayed Recall of a Story; Verbal Fluency for P and S, Fruits and Animals; Clock Drawing; Temporal Orientation; and Trail Making tests. We report distributions of scores over time, at each wave, in (a) all individuals who were assessed at that wave, whether or not they participated in all waves, and (b) the Survivor subgroup of 425 participants who completed all tests at all 5 waves. Scores and factor structures remained remarkably stable over the study period.

Sedative-hypnotic use of diphenhydramine in a rural, older adult, community-based cohort: effects on cognition.

Objective: The authors sought to identify patterns and associations of prescription and over-the-counter sedative-hypnotic use in an older, rural, blue-collar, community-based cohort in southwestern Pennsylvania over 10 years.

Methods: A group of 1,627 individuals age 65 and over were recruited and assessed during 1987-1989 and re-assessed during approximately biennial waves. Data included sleep medications, demographics, depressive symptoms, sleep complaints, and cognitive functioning (Mini-Mental State Exam [MMSE]).

Functional transitions and active life expectancy associated with Alzheimer disease.

Context: The concept of active life expectancy, the number of years a person can expect to live without disability, is used for the first time, to our knowledge, to examine the effect of Alzheimer disease (AD) on total life expectancy with different degrees of disability.

Objectives: To estimate and compare total life expectancy and average duration lived with different degrees of disability, between persons with and without AD.

Design: Ten-year prospective epidemiologic study.

Serum anticholinergic activity in a community-based sample of older adults: relationship with cognitive performance.

Background: Serum anticholinergic activity (SAA), as measured by a radioreceptor assay, quantifies a person's overall anticholinergic burden caused by all drugs and their metabolites. In several small geriatric patient groups, SAA has been associated with cognitive impairment or frank delirium. To our knowledge, there has not yet been any systematic study of the prevalence of SAA and its effect on cognition in a community-based population.

Rates and predictors of mortality in an aging, rural, community-based cohort: the role of depression.

Context: Depression, functional disability, cognitive impairment, and self-rated health all predict mortality in the elderly population. There is no consensus on their relative contributions when examined together.

Objectives: To measure rates and identify predictors of mortality in an aging community-based cohort.

Use of lipid-lowering drugs in older adults with and without dementia: a community-based epidemiological study.

Objectives: To compare the use of lipid-lowering drugs in community-dwelling older adults with and without dementia.

Design: Comparison of lipid-lowering drug use by demented cases and nondemented controls based on secondary analysis of data from a longitudinal epidemiologic study.

Setting: Longitudinal study of a largely rural, low- socioeconomic-status, community-based cohort of older persons residing in the mid-Monongahela Valley of South-west Pennsylvania (the Monongahela Valley Independent Elders Survey).

Hypothyroidism and cognition: preliminary evidence for a specific defect in memory.

The effect(s) of hypothyroidism on adult brain cognitive function are poorly understood. We performed a series of neuropsychological tests in 13 thyroid cancer patients while they continued to take their usual dose of levothyroxine (LT4) and again after discontinuing thyroid hormone. Three euthyroid subjects were also tested twice to assess the effect of repeated testing on performance.

Data management and quality assurance for an International project: the Indo-US Cross-National Dementia Epidemiology Study.

Background: Data management and quality assurance play a vital but often neglected role in ensuring high quality research, particularly in collaborative and international studies.

Objective: A data management and quality assurance program was set up for a cross-national epidemiological study of Alzheimer's disease, with centers in India and the United States.

Methods: The study involved (a) the development of instruments for the assessment of elderly illiterate Hindi-speaking individuals; and (b) the use of those instruments to carry out an epidemiological study in a population-based cohort of over 5000 persons.