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Biomedical subjects

M Albert

Publications and source records attributed to M Albert.

At least 73 records · Page 4Linked to original sources
PubMed1998

A study of the efficacy of a comprehensive memory enhancement program in healthy elderly persons.

Well educated, high functioning older adults (ages 60-90) were given a comprehensive memory enhancement training program to determine the effectiveness of the program in increasing cognitive performance and positively influencing self-assessments of memory efficacy. The 68 subjects who participated in the memory enhancement training were compared to 74 subjects who were enrolled in a video control group. Between subject differences were analyzed prior to the interventions and at three time points following the interventions (immediately post, 3 months and 6 months). Only one cognitive measure, assessing verbal memory, revealed a significant difference between the groups, with participants in the memory enhancement group showing less decline from baseline than the video control group immediately following the intervention but with no difference between groups at 6 months post-intervention. Several self-report measures showed that the memory enhancement training subjects experienced improved memory functioning and decreased memory concerns relative to the video control group. The self-reported effects of the training were sustained over the 6-month follow-up period.

Adult↗
PubMed1998

The distinctive features of influenza virus infection of dendritic cells.

CD8+ cytolytic T lymphocytes (CTLs) are considered to be critical mediators for resistance to influenza virus infection. We have previously demonstrated that dendritic cells are potent antigen presenting cells in the development of anti-influenza CTLs. Here we identify distinctive features of the interaction of influenza virus with dendritic cells. Exposure of dendritic cells to influenza virus at MOIs of 2-4:1 leads to > 90% infection, as manifested by the expression of the viral proteins HA and NS1. The infection is non-toxic as viral protein expression is sustained for > 2 days with retention of viability, but little infectious virus is produced. Substantial induction of the anti-viral cytokine IFN-alpha also occurs. Influenza infection of macrophages also results in viral protein expression in a majority of cells, and synthesis of IFN-alpha. In contrast to dendritic cells, macrophages display evidence of apoptosis within 10-12 hours, and the majority of cells die within 24-36 hours. During this interval macrophages synthesize > 10-fold higher levels of virus than dendritic cells. Infected dendritic cells but not macrophages, can induce substantial CTL responses from purified blood CD8+ T cells in the absence of exogenous cytokines such as IL-2. Low levels of infection (MOIs of 0.02) are sufficient to generate potent CTL responses. Influenza virus expressing non-cleaved HA does not elicit CTLs indicating that virus must access the cytoplasm of dendritic cells to utilize traditional class I processing pathways. These observations indicate that DCs are distinct in their handling of influenza virus and for the induction of anti-viral immunity.

Animals↗
PubMed1998

Genetic association of an alpha2-macroglobulin (Val1000lle) polymorphism and Alzheimer's disease.

alpha2-Macroglobulin (A2M) is a proteinase inhibitor found in association with senile plaques (SP) in Alzheimer's disease (AD). A2M has been implicated biochemically in binding and degradation of the amyloid beta (Abeta) protein which accumulates in SP. We studied the relationship between Alzheimer's disease and a common A2M polymorphism, Val1000 (GTC)/Ile1000 (ATC), which occurs near the thiolester active site of the molecule. In an initial exploratory data set (90 controls and 171 Alzheimer's disease) we noted an increased frequency of the G/G genotype from 0.07 to 0.12. We therefore tested the hypothesis that the G/G genotype is over-represented in Alzheimer's disease in an additional independent data set: a group of 359 controls and 566 Alzheimer's disease patients. In the hypothesis testing cohort, the G/G genotype increased from 0.07 in controls to 0.12 in Alzheimer's disease (P < 0.05, Fisher's exact test). The odds ratio for Alzheimer's disease associated with the G/G genotype was 1.77 (1.16-2.70, P < 0.01) and in combination with APOE4 was 9.68 (95% CI 3.91-24.0, P < 0.001). The presence of the G allele was associated with an increase in Abeta burden in a small series. The A2M receptor, A2M-r/LRP, is a multifunctional receptor whose ligands include apolipoprotein E and the amyloid precursor protein. These four proteins have each been genetically linked to Alzheimer's disease, suggesting that they may participate in a common disease pathway.

Alleles↗
PubMed1998

Coagulation and thrombomodulin in response to exercise of different type and duration.

PURPOSE: The present study was conducted to evaluate the role of the duration of exercise and the impact of the exercise type for exercise-induced activation of coagulation. METHODS: Eleven male triathletes were subjected to stepwise maximal (17 min) and 1-h maximal exercise in swimming, cycling, and running. Changes of hemostatic variable sand of plasma thrombomodulin, a marker of endothelial cell activation, were monitored. RESULTS: Irrespective of the type of exercise, alterations in markers of thrombin (prothrombin fragment 1 + 2, thrombin-antithrombin III complexes) and fibrin formation (fibrinopeptide A) were more pronounced after 1-h exercise than after stepwise maximal exercise. Hemostatic parameters rose to the highest levels after running resulting in substantial fibrin formation as indicated by fibrinopeptide A increasing from 1.33 ng.mL-1 to 2.25 ng.mL (P < 0.05) after 1-h exercise testing. Significant changes of plasma thrombomodulin were detected exclusively after running with increases from 38.2 ng.mL-1 to 44.2 ng.mL-1 (1 h, P < 0.01). CONCLUSIONS: The data demonstrated that prolonged exercise is necessary for exercise-induced activation of coagulation resulting in thrombin and fibrin formation and suggested that endothelial cell activation possibly due to mechanical factors associated with running might play a role.

Adult↗
PubMed1998

Social networks and mental health service utilisation--a literature review.

Social networks have been shown to be smaller in individuals with severe mental illness than in the general population. Patients' social networks and social support may impact on their utilisation of psychiatric services. This literature review focuses on social networks, social support and mental health service use in patients with mental illness. Most studies suggest that smaller social networks or less social support are associated with more frequent hospitalisation. Qualitative aspects of the social network are also related to the risk of hospitalisation. The relationship between social networks and other types of service use is not established.

Ambulatory Care↗
PubMed1998

Frontotemporal lobar degeneration: a consensus on clinical diagnostic criteria.

OBJECTIVE: To improve clinical recognition and provide research diagnostic criteria for three clinical syndromes associated with frontotemporal lobar degeneration. METHODS: Consensus criteria for the three prototypic syndromes-frontotemporal dementia, progressive nonfluent aphasia, and semantic dementia-were developed by members of an international workshop on frontotemporal lobar degeneration. These criteria build on earlier published clinical diagnostic guidelines for frontotemporal dementia produced by some of the workshop members. RESULTS: The consensus criteria specify core and supportive features for each of the three prototypic clinical syndromes and provide broad inclusion and exclusion criteria for the generic entity of frontotemporal lobar degeneration. The criteria are presented in lists, and operational definitions for features are provided in the text. CONCLUSIONS: The criteria ought to provide the foundation for research work into the neuropsychology, neuropathology, genetics, molecular biology, and epidemiology of these important clinical disorders that account for a substantial proportion of cases of primary degenerative dementia occurring before the age of 65 years.

Dementia↗
PubMed1997

The course of psychopathologic features in mild to moderate Alzheimer disease.

BACKGROUND: The onset and course of the psychopathologic features of Alzheimer disease have not been established in prospective, longitudinal studies. METHODS: Two hundred thirty-five patients with early, probable Alzheimer disease were recruited at 3 sites and observed naturalistically for up to 5 years. At 6-month intervals, the Columbia University Scale for Psychopathology in Alzheimer's Disease was administered. Markov analyses were used to predict the probability of a specific symptom developing or being maintained at the next visit. For each symptom category, the maximum frequency of occurrence at 4 consecutive points (duration, 2 years) was calculated. RESULTS: Misidentification, wandering or agitation, and physical aggression increased during follow-up. At any visit, the likelihood of a new symptom developing was greatest for behavioral disturbance, intermediate for paranoid delusions and hallucinations, and least for depressed mood with vegetative features. Wandering or agitation occurred at 3 or more of 4 consecutive visits (duration, 2 years) in the majority of patients, paranoid delusions and hallucinations were intermediate in their degree of persistence, and depressed mood with vegetative signs rarely persisted. CONCLUSIONS: Behavioral disturbance, particularly agitation, is common and persistent in patients with Alzheimer disease. Psychotic symptoms are less common and show moderate persistence over time. Depressed mood with vegetative signs is uncommon and rarely persists. These findings suggest leads about the optimal treatment duration for specific subtypes of psychopathologic features.

Aged↗
PubMed1997

The absence of an apolipoprotein epsilon4 allele is associated with a more aggressive form of Alzheimer's disease.

We investigated the relationship between APOE genotype and rate of disease progression and survival in 99 patients with probable Alzheimer's disease (AD) who were followed biannually for up to 6 years. Patients were stratified into two groups, those with and without at least one APOE epsilon4 allele. The rate of decline in modified Mini-Mental State Examination scores was slower, the presence of extrapyramidal signs was decreased, and the development of myoclonus occurred later among patients with APOE epsilon4 alleles compared with patients with other genotypes. Compared with patients without an APOE epsilon4 allele, the risk of mortality was also decreased in patients with at least one epsilon4 allele (RR = 0.38; CI = 0.17-0.84, p < 0.02). Because the decline in mental ability as well as the development of myoclonus and extrapyramidal signs are consistent manifestations of disease progression, our results imply that APOE epsilon4 is associated with a less aggressive form of AD.

Age of Onset↗
PubMed1997

Semi-automated extraction of brain contours from MRI.

We compared brain volumes computed by trained operators using the BRAIN-MAP algorithm, which automatically extracts the contours of the brain from gradient-echo magnetic resonance images. The images of 19 subjects randomly selected from a group of normals and a group of patients with dementia were included. BRAIN-MAP found brain perimeters that were on the average ca. 3% tighter than those obtained by two experienced operators. Between-operator and within-operator reproducibility of the analyses were also estimated and found to be (-0.13 +/- 0.51)% and (-0.63 +/- 0.08)%, respectively. Replicate volume measurement by the computer alone provided a reproducibility of (0.44 +/- 0.46)%.

Adult↗
PubMed1997

Social networks and service use among representative cases of psychosis in south London.

BACKGROUND: Large social networks in patients with severe mental illness have been reported to be associated with a low rate of hospitalisation. We aim to determine whether social network size is related to the likelihood of hospitalisation and the amount of service use. METHOD: As part of a prospective controlled study, baseline interview data for a random sample of one-year prevalent cases with non-organic psychosis were analysed with respect to social network characteristics and service use during a six-month period. RESULTS: The likelihood of hospitalisation decreased with an increase in network size, while the number of services used by patients grew as the social network size increased. CONCLUSIONS: While larger social networks may be associated with a lower likelihood of hospitalization, they may also be related to wider use of non-hospital services.

Adolescent↗
PubMed1997

Participation in clinical trials and long-term outcomes in Alzheimer's disease.

The objective of this study was to determine whether participation in clinical trials affects long-term outcomes in Alzheimer's disease (AD). Participation in clinical trials for persons with dementia is often justified on the grounds that patients benefit from the medical oversight typical of trials, even when experimental agents do not demonstrate short-term benefits. This claim has not been rigorously assessed. Of 215 community-resident subjects enrolled in a prospective study of outcomes in AD, 101 participated in randomized clinical trials (RCTs) during the first 2 years of follow-up. These subjects were compared with subjects who met eligibility requirements for RCTs but did not participate (N = 57) and with subjects who were ineligible (N = 57), over a total of 3.5 years of follow-up. Survival analyses assessed risk of death, nursing home placement, and incident functional deficit end points, adjusting for baseline differences. Subjects who participated in RCTs were younger and more highly educated. Mortality, risk of hospitalization, number of medical examinations conducted by study physicians, and onset of severe functional deficit did not differ between the groups, but risk of nursing home admission was significantly lower among RCT participants compared with eligible nonparticipants and ineligible subjects (16.8% versus 36.8% and 31.6%, respectively [p = 0.01]). The difference in risk of nursing home placement may represent a long-term, drug-related benefit to patients, a selection effect (caregivers of patients who participate in RCTs differ from caregivers of patients who do not), or a positive effect on caregivers (greater contact with a medical service may be associated with better care-giving outcomes). Further research is required to assess these effects.

Aged↗
PubMed1997

Hepatic ultrasonographic findings in experimental carbon tetrachloride intoxication of the dog.

An experimental study was undertaken in dogs with carbon tetrachloride (CCl4) intoxication to describe and follow the changes in the ultrasound appearance of the liver. Characteristic ultrasound features (enlarged liver, increased echogenicity with fine, tightly-packed echoes, and loss of echogenicity of the portal vein walls) were seen from day 2 of the experiment, culminating between days 2 and 7. Subsequently the liver gradually and almost completely regained its normal ultrasound appearance. Ultrasonographic findings corresponded to the severity of the clinicopathological parameters, and changed parallel with the results of liver biopsies. Histology of the biopsy samples revealed acute centrolobular lipid accumulation with necrobiosis and necrosis in the hepatocytes in the first stage of the disease. In the second stage, a secondary reparatory-inflammatory process and reparation in the interstitial tissue were seen. In some dogs, ill-defined hyperechoic foci were observed within the liver during the regenerative phase. Hepatic ultrasonography seems to be a reliable and relatively sensitive method for monitoring liver dystrophy with necrobiosis and lipid accumulation and to follow the course of steatosis in clinical cases. Ultrasound-guided biopsy can further improve the diagnostic accuracy of ultrasonography in liver dystrophy.

Alanine Transaminase↗
PubMed1996

Modeling the influence of extrapyramidal signs on the progression of Alzheimer disease.

OBJECTIVE: To determine how the advent of extrapyramidal signs influences the progression of Alzheimer disease as measured by standard clinical measures. DESIGN: We applied growth curve models to prospective data to characterize patients' cognitive and functional changes over time. To detect changes in disease course related to extrapyramidal signs, their onset was treated as a time-dependent covariate. SETTING: Three research medical centers. PARTICIPANTS: Patients (n = 217) with probable Alzheimer disease. INTERVENTION: Patients were followed up semiannually for 5 years. MAIN OUTCOME MEASURES: Scores on the modified Mini-Mental State Examination and measures of basic and instrumental activities of daily living from the Blessed Dementia Rating Scale. RESULTS: For basic and instrumental activities of daily living, disease course was more rapid once extrapyramidal signs developed. Decline in the modified Mini-Mental State Examination score was greater at the time the signs developed, but not at subsequent visits. CONCLUSIONS: The point at which extrapyramidal signs emerge is associated with measurable acceleration in the progression of Alzheimer disease. This may in part explain why extrapyramidal signs are associated with a poorer prognosis. The differential influence of extrapyramidal signs on cognitive and functional measures suggests that the pathological changes underlying these disease features may vary.

Aged↗
PubMed1996

Comparison of receiver operating characteristic curves on the basis of optimal operating points.

RATIONALE AND OBJECTIVES: We developed a method of comparing receiver operating characteristic (ROC) curves on the basis of the utilities associated with their optimal operating points (OOPs). METHODS: OOPs were computed for paired ROC curves on the basis of isocost lines in ROC space with slopes ranging from 0.1 to 3.0. For each pair of OOPs corresponding to a single isocost slope, the difference in costs and the variance of this difference was computed. A sensitivity analysis was thus obtained for the difference between the two curves over a range of isocost slopes. Three published data sets were evaluated using this technique, as well as by comparisons of areas under the curves and of true-positive fractions at fixed false-positive fractions. RESULTS: The OOPs of paired ROC curves often occur at different false-positive fractions. Comparisons of ROC curves on the basis of OOPs may provide results that differ from comparisons of curves at a fixed false-positive fraction. CONCLUSION: ROC curves may be compared on the basis of utilities associated with their OOPs. This comparison of the optimal performance of two diagnostic tests may differ from conventional statistical comparisons.

Costs and Cost Analysis↗
PubMed1996

Self-efficacy beliefs and change in cognitive performance: MacArthur Studies of Successful Aging.

Data from a cohort of relatively high functioning, older men and women were used to test the hypothesis that stronger self-efficacy beliefs predict better maintenance of cognitive performance. Structural equation modeling revealed that stronger baseline instrumental efficacy beliefs predicted better verbal memory performance at follow-up among men but not among women, controlling for baseline verbal memory score and sociodemographic and health status characteristics. For both men and women there were no significant associations between either type of self-efficacy beliefs and measures of nonverbal memory, abstraction, or spatial ability. Consistent with previous research showing relationship between baseline cognitive performance and change in self-efficacy beliefs, better abstraction ability was also predictive of increase in instrumental efficacy beliefs among the men.

Age Factors↗
PubMed1996

Application of a growth curve approach to modeling the progression of Alzheimer's disease.

BACKGROUND: Studies using clinical measures to track AD progression often assume linear declines over the entire course of the disease, which may not be justified. The objective of this study was to model change in measures of the clinical severity of Alzheimer's disease (AD) over time. METHODS: We developed a method to apply growth curve models to prospective data and characterize AD patients' functional change over time. Data from the modified Mini-Mental State Examination (mMMSE) and measures of basic and instrumental ADL, administered semiannually for up to 5 years to 236 patients with probable AD, were modeled. RESULTS: The rate of decline in mMMS scores per 6-month interval gradually increased as scores dropped from the maximum of 57 to 20. The rate of decline then decreased as scores approached 0, resulting in an inverse "S" curve. The rate of increase in instrumental ADL scores per interval attenuated as the scores increased, while that for basic ADL scores across intervals was constant. CONCLUSIONS: Differences in the pattern of progression of the three measures is in part a function of their psychometric properties. The progression curves may also reflect content-specific features of the instruments. Superimposition of the modeled decline in these three content areas suggests a hypothetical model of the relative timing of cognitive and functional changes in AD.

Activities of Daily Living↗
PubMed1996

Quality of life in patients with Alzheimer's disease as reported by patient proxies.

OBJECTIVE: To measure behaviors indicative of quality of life (QOL) in patients with Alzheimer's disease and to examine correlates of patient QOL. DESIGN: Cross-sectional investigation. SETTING: Multi-center study. PARTICIPANTS: Sample of 130 diagnosed patients. PRINCIPAL OUTCOME MEASURES: Proxy ratings of (1) the frequency, opportunity, and enjoyment of 15 non-ADL activities potentially within the capacity of a demented person, and (2) the frequency of a series of positive and negative affects, evident in clearly demarcated facial and bodily expressions. RESULTS: QOL ratings were reliably elicited. Family and institutional caregivers differed only in reports of opportunity for patient activity. Frequency of activities declined with increasing severity of dementia. The frequency of negative affects increased and positive affects declined with increasing severity of dementia, but correlations were weak. High QOL, defined by frequent activity and positive affect, was evident in a quarter of the sample. In multivariate models, functional and cognitive status independently predicted QOL among community-resident older adults; only absence of antipsychotics was related to QOL among older people in nursing homes. Patient education, a marker of premorbid state, independently predicted some activity patterns. CONCLUSIONS: Although the subjective world of the demented patient is not directly accessible, readily observable behaviors offer a basis for assessing QOL.

Affect↗