Showing papers by "University of Washington published in 1989"

The consortium to establish a registry for alzheimer’s disease (CERAD). Part I. Clinical and neuropsychological assessment of alzheimer’s disease

Abstract: The Consortium to Establish a Registry for Alzheimer's Disease (CERAD) has developed brief, comprehensive, and reliable batteries of clinical and neuropsychological tests for assessment of patients with the clinical diagnosis of Alzheimer's disease (AD). We administered these batteries in a standardized manner to more than 350 subjects with a diagnosis of AD and 275 control subjects who were enrolled in a nationwide registry by a consortium of 16 university medical centers. The tests selected for this study measured the primary cognitive manifestations of AD across a range of severity of the disorder, and discriminated between normal subjects and those with mild and moderate dementia. The batteries also detected deterioration of language, memory, praxis, and general intellectual status in subjects returning for reassessment 1 year later. Interrater and test-retest reliabilities were substantial. Long-term observations of this cohort are in progress in an effort to validate the clinical and neuropsychological assessments and to confirm the diagnosis by postmortem examinations. Although information on validation is limited thus far, the CERAD batteries appear to fill a need for a standardized, easily administered, and reliable instrument for evaluating persons with AD in multicenter research studies as well as in clinical practice.

Checkpoints: controls that ensure the order of cell cycle events

Abstract: The events of the cell cycle of most organisms are ordered into dependent pathways in which the initiation of late events is dependent on the completion of early events. In eukaryotes, for example, mitosis is dependent on the completion of DNA synthesis. Some dependencies can be relieved by mutation (mitosis may then occur before completion of DNA synthesis), suggesting that the dependency is due to a control mechanism and not an intrinsic feature of the events themselves. Control mechanisms enforcing dependency in the cell cycle are here called checkpoints. Elimination of checkpoints may result in cell death, infidelity in the distribution of chromosomes or other organelles, or increased susceptibility to environmental perturbations such as DNA damaging agents. It appears that some checkpoints are eliminated during the early embryonic development of some organisms; this fact may pose special problems for the fidelity of embryonic cell division.

Generic and disease-specific measures in assessing health status and quality of life.

Abstract: Application of generic and specific measures of health status and quality of life to different diseases, conditions, states, and populations is increasing. Four strategies for using these measures are separate generic and specific measures, modified generic measures, disease-specific supplements, and batteries. The preferred strategy depends on project aims, methodological concerns, and practical constraints. Generic measures are necessary to compare outcomes across different populations and interventions, particularly for cost-effectiveness studies. Disease-specific measures assess the special states and concerns of diagnostic groups. Specific measures may be more sensitive for the detection and quantification of small changes that are important to clinicians or patients. Comparison studies are needed of the validity, reliability, and responsiveness of generic and disease-specific measures in the same population and in minority and age-specific groups.

Cloud-radiative forcing and climate: results from the Earth radiation budget experiment.

Abstract: The spaceborne Earth Radiation Budget Experiment was begun in 1984 to obtain quantitative estimates of the global distributions of cloud-radiative forcing The magnitude of the observed net cloud forcing is about four times greater than the expected value of radiative forcing from a doubling of CO2; the shortwave and longwave components of cloud forcing are about 10 times as large as those for a CO2 doubling Small changes in the cloud-radiative forcing fields can therefore play a significant role as a climate-feedback mechanism

Economic analysis of property rights

Abstract: Introduction 1. The property rights model 2. The public domain: rationing by waiting and price controls 3. Contract choice: the tenancy contract 4. Divided ownership 5. The old firm and the new organization 6. The formation of rights 7. Slavery 8. Wealth maximization constraints on property rights 9. Property rights and non-market allocation 10. Additional property rights applications 11. The property rights model: recapitulation References.

Determinants of firm performance: the relative importance of economic and organizational factors

Abstract: We decompose the inter-firm variance in profit rates into economic and organizational components. Using a representative model from each paradigm we find that both sets of factors are significant determinants of firm performance. Further findings are that the two effects are roughly independent and that organizational factors explain about twice as much variance in profit rates as economic factors.

Nosocomial acquisition of Clostridium difficile infection

Abstract: We studied the acquisition and transmission of Clostridium difficile infection prospectively on a general medical ward by serially culturing rectal-swab specimens from 428 patients admitted over an 11-month period. Immunoblot typing was used to differentiate individual strains of C. difficile. Seven percent of the patients (29) had positive cultures at admission. Eighty-three (21 percent) of the 399 patients with negative cultures acquired C. difficile during their hospitalizations. Of these patients, 52 (63 percent) remained asymptomatic and 31 (37 percent) had diarrhea; none had colitis. Patient-to-patient transmission of C. difficile was evidenced by time-space clustering of incident cases with identical immunoblot types and by significantly more frequent and earlier acquisition of C. difficile among patients exposed to roommates with positive cultures. Of the hospital personnel caring for patients with positive cultures, 59 percent (20) had positive cultures for C. difficile from their hands. The hospital rooms occupied by symptomatic patients (49 percent) as well as those occupied by asymptomatic patients (29 percent) were frequently contaminated. Eighty-two percent of the infected cohort still had positive cultures at hospital discharge, and such patients were significantly more likely to be discharged to a long-term care facility. We conclude that nosocomial C. difficile infection, which was associated with diarrhea in about one third of cases, is frequently transmitted among hospitalized patients and that the organism is often present on the hands of hospital personnel caring for such patients. Effective preventive measures are needed to reduce nosocomial acquisition of C. difficile.

Social Utility and Decision Making in Interpersonal Contexts

Abstract: Three studies examined preferences for outcomes to self and a codisputant. Studies I and 2 estimated social utility functions from judgments of satisfaction with alternative outcomes. Comparing functional forms, we found that a utility function, including terms for own payoff and for positive and negative discrepancies between the parties' payoffs (advantageous and disadvantageous inequality), provides a close fit to the data. The typical utility function is steeply increasing and convex for disadvantageous inequality and weakly declining and convex for advantageous inequality. We manipulated dispute type (personal, business) and disputant relationship (positive, neutral, or negative) and found that both strongly influence preferences for advantageous but not disadvantageous inequality. A third study contrasted implications of the social utility functions with predictions of individual utility theories. People care about the outcomes of others. We sacrifice our own interests to help loved ones or harm adversaries. Participants withdraw from profitable participation in a laboratory experiment if they perceive inequity in remuneration (Schmitt & Marweli, 1972). Players in two-person ultimatum games (in which one player proposes a distribution of a fixed amount of money that the other has the option of either accepting or rejecting) frequently reject a positive but inequitable offer even though the alternative is no gain at all (Guth, Schmittberger, & Schwarze, 1982). Negotiations between parties often collapse when one party becomes incensed with the other and attempts to "maximize his opponent's displeasure rather than his own satisfaction" (scigel & Fouraker, 1960, p. 100). In general, disputants are concerned not only with the outcomes they receive, but also with the outcomes of their opponents (Pruitt & Rubin, 1986).

Evolution of thermal sensitivity of ectotherm performance.

Abstract: Most ectothermal animals have variable body temperatures. Because physiological rates are temperature sensitive, an ectotherm's behavioural and ecological performance - even its fitness - can be influenced by body temperature. As a result, the thermal sensitivity of ectotherm performance is relevant to diverse issues in physiology, ecology and evolution. This review formalizes an emerging framework for investigating the evolution of thermal sensitivity, outlines some functional and genetical constraints on that evolution, and summarizes comparative and experimental advances in this field.

Extraction of DNA from plant tissues

Abstract: Extraction procedures for plant DNA in general must accomplish the following. (1) The cell walls must be broken (or digested away) in order to release the cellular constituents. This is usually done by grinding the tissue in dry ice or liquid nitrogen with a mortar and pestel or a food grinder. (2) The cell membranes must be disrupted, so that the DNA is released into the extraction buffer. This is accomplished by using a detergent, usually SDS (sodium dodecyl sulfate) or CTAB (cetyltrimethylammonium bromide). (3) The DNA must be protected from the endogenous nucleases. The detergents are used for this purpose, as is EDTA (ethylenediaminetetraacetic acid). It is a chelating agent that binds magnesium ions, generally considered a necessary cofactor for most nucleases (but see note f, below). In addition, the buffer/tissue mixture is emulsified with either chloroform or phenol to denature and separate the proteins from the DNA. (4) Shearing of the DNA should be minimized. DNA in solution can be broken by exposure to turbulence (e.g., being quickly drawn through a small orifice). Typically, DNA 50–100 kb in length can be obtained without great care being taken. (5) The time between thawing of the frozen, pulverized tissue and its exposure to the extraction buffer should be minimized to avoid nucleolytic degradation of the DNA.

Spontaneous vesicle formation in aqueous mixtures of single-tailed surfactants

Abstract: Spontaneous, single-walled, equilibrium vesicles can be prepared from aqueous mixtures of simple, commercially available, single-tailed cationic and anionic surfactants. Vesicle size, surface charge, or permeability can be readily adjusted by varying the ratio of anionic to cationic surfactant. Vesicle formation apparently results from the production of anion-cation surfactant pairs that then act as double-tailed zwitterionic surfactants. These vesicles are quite stable in comparison to conventional vesicles prepared by mechanical disruption of insoluble liquid crystalline dispersions.

Marital interaction and satisfaction: a longitudinal view.

Abstract: Two longitudinal studies of marital interaction were conducted using observational coding of couples attempting to resolve a high-conflict issue. We found that a different pattern of results predicts concurrent marital satisfaction than predicts change in marital satisfaction over 3 years. Results suggest that some marital interaction patterns, such as disagreement and anger exchanges, which have usually been considered harmful to a marriage, may not be harmful in the long run. These patterns were found to relate to unhappiness and negative interaction at home concurrently, but they were predictive of improvement in marital satisfaction longitudinally. However, three interaction patterns were identified as dysfunctional in terms of longitudinal deterioration: defensiveness (which includes whining), stubbomess. and withdrawal from interaction. Hypotheses about gender differences in roles for the maintenance of marital satisfaction are presented.

Effects of alternative training methods on self-efficacy and performance in computer software training

Abstract: Comparaison des differentes methodes d'entrainement a l'efficacite personnelle et a la maitrise d'un programme logiciel informatise, dnas le cadre d'une experience reelle impliquant 108 dirigeants d'universite. Implications sur les modes des interventions preferables pour obtenir les meilleurs resultats (imitation, tutorat, etc.)

Research Methods in Occupational Epidemiology

Abstract: 1. Introduction 2. Characterizing the workplace environment 3. Overview of study designs 4. Precision and validity in study design 5. Cohort studies 6. Case-control studies 7. Cross-sectional and repeated measure studies 8. Occupational health surveillance 9. Advanced statistical analysis 10. Exposure and dose modelling 11. Special applications of occupational epidemiology

Interannual variability in a tropical atmosphere−ocean model: influence of the basic state, ocean geometry and nonlinearity

Abstract: The behavior of a tropical coupled atmosphere/ocean model is analyzed for a range of different background states and ocean geometries. The model is essentially that of Cane and Zebiak for the tropical Pacific, except only temporally constant background states are considered here. For realistic background states and ocean geometry, the model solutions feature oscillations of period of 3–5 yr. By comparing the full model solution with a linearized version of the model, it is shown that the basic mechanism of the oscillation is contained within linear theory. A simple linear analog model is derived that describes the nature of the interannual variability in the coupled tropical atmosphere–ocean system. The analog model highlights the properties that produce coupled atmosphere–ocean instability in the eastern ocean basin, and the equatorial wave dynamics in the western ocean basin that are responsible for a delayed, negative feedback into this instability growth. The growth rate of the local instabil...

Designing Density Fluctuation Spectra in Inflation

Abstract: Scale-invariant (flat) fluctuation spectra are the most natural outcomes of inflation. Nonetheless current large-scale-structure observations seem to indicate more fluctuation power on large scales than flat spectra give. We consider a wide variety of models based on the chaotic inflation paradigm and sketch the effects that varying the expansion rate, structure of the potential surface, and the curvature coupling constants have on the quantum fluctuation spectra. We calculate in detail the quantum generation of fluctuation spectra by numerically solving the linearized perturbation equations for multiple scalar fields, the metric, and the radiation into which the scalars dissipate, following the evolution from inside the horizon through reheating.

Pose estimation from corresponding point data

Abstract: Solutions for four different pose estimation problems are presented. Closed-form least-squares solutions are given to the overconstrained 2D-2D and 3D-3D pose estimation problems. A globally convergent iterative technique is given for the 2D-perspective-projection-3D pose estimation problem. A simplified linear solution and a robust solution to the 2D-perspective-projection-2D-perspective-projection pose-estimation problem are also given. Simulation experiments consisting of millions of trials with varying numbers of pairs of corresponding points and varying signal-to-noise ratios (SNRs) with either Gaussian or uniform noise provide data suggesting that accurate inference of rotation and translation with noisy data may require corresponding point data sets with hundreds of corresponding point pairs when the SNR is less than 40 dB. The experimental results also show that the robust technique can suppress the blunder data which come from outliers or mismatched points. >

Criteria for success of osseointegrated endosseous implants.

Abstract: Because of the proliferation of implant systems, a set of criteria for implant success based on scientific investigations is essential. A review of the literature and the analysis of the results indicate that six criteria are supported as valid for determining the clinical success of endosseous dental implants. These criteria are proposed for use in clinical investigation on implants.

Interleukin-1 mitogenic activity for fibroblasts and smooth muscle cells is due to PDGF-AA.

Abstract: Both interleukin-1 (IL-1) and platelet-derived growth factor (PDGF) induce proliferation of cultured fibroblasts and smooth muscle cells. These polypeptide mediators are released by activated macrophages and other cell types in response to injury and are thought to have a role in tissue remodeling and a number of pathologic processes. Analysis of the kinetics of [3H]thymidine incorporation by cultured fibroblasts demonstrated that the response to IL-1 is delayed approximately 8 hours relative to their response to PDGF. IL-1 transiently stimulated expression of the PDGF A-chain gene, with maximum induction after approximately 2 hours. Subsequent synthesis and release of PDGF activity into the medium was detected as early as 4 hours after IL-1 stimulation, and downregulation of the binding site for the PDGF-AA isoform of PDGF followed PDGF-AA secretion. Antibodies to PDGF completely block the mitogenic response to IL-1. Therefore, the mitogenic activity of IL-1 for fibroblasts and smooth muscle cells appears to be indirect and mediated by induction of the PDGF A-chain gene.

Magnification of secondary production by kelp detritus in coastal marine ecosystems

Abstract: Kelps are highly productive seaweeds found along most temperate latitude coastlines, but the fate and importance of kelp production to nearshore ecosystems are largely unknown. The trophic role of kelp-derived carbon in a wide range of marine organisms was assessed by a natural experiment. Growth rates of benthic suspension feeders were greatly increased in the presence of organic detritus (particulate and dissolved) originating from large benthic seaweeds (kelps). Stable carbon isotope analysis confirmed that kelp-derived carbon is found throughout the nearshore food web.

Prevalence of hydrogen peroxide-producing Lactobacillus species in normal women and women with bacterial vaginosis.

Abstract: A predominance of Lactobacillus species in the vaginal flora is considered normal. In women with bacterial vaginosis, the prevalence and concentrations of intravaginal Gardnerella vaginalis and anaerobes are increased, whereas the prevalence of intravaginal Lactobacillus species is decreased. Because some lactobacilli are known to produce hydrogen peroxide (H2O2), which can be toxic to organisms that produce little or no H2O2-scavenging enzymes (e.g., catalase), we postulated that an absence of H2O2-producing Lactobacillus species could allow an overgrowth of catalase-negative organisms, such as those found among women with bacterial vaginosis. In this study, H2O2-producing facultative Lactobacillus species were found in the vaginas of 27 (96%) of 28 normal women and 4 (6%) of 67 women with bacterial vaginosis (P less than 0.001). Anaerobic Lactobacillus species (which do not produce hydrogen peroxide) were isolated from 24 (36%) of 67 women with bacterial vaginosis and 1 (4%) of 28 normal women (P less than 0.001). The production of H2O2 by Lactobacillus species may represent a nonspecific antimicrobial defense mechanism of the normal vaginal ecosystem.

Treatment of Wilms' tumor. Results of the Third National Wilms' Tumor Study.

Abstract: The Third National Wilms' Tumor Study sought to reduce treatment for low-risk patients and find better chemotherapy for those at high risk for relapse. Eligible patients (1439) were randomized according to stage (I-IV) and histology (favorable [FH] or unfavorable [UH]), and contributed data to survival and relapse-free survival (RFS) analyses. Four-year (postnephrectomy) survival percentages and randomized treatment regimens for low-risk patients were 96.5% for 607 Stage I/FH patients who received dactinomycin (Actinomycin D [AMD], Merck Sharp & Dohme, West Point, PA) and vincristine (VCR) for 10 weeks versus 6 months; 92.2% for 278 Stage II/FH patients; and 86.9% for 275 Stage III/FH patients who received AMD + VCR +/- Adriamycin (ADR, Adria Laboratories, Columbus, OH) for 15 months. Stage II/FH patients also had either zero or 2000 cGy irradiation (RT) postoperatively and Stage III/FH patients either 1000 or 2000 cGy. Four-year survival was 73.0% for 279 high-risk patients (any Stage IV, all UH) who received postoperative radiation therapy (RT) and AMD + VCR + ADR +/- cyclophosphamide (CPM). Statistical analysis of survival and RFS experience shows that the less intensive therapy does not worsen results for low-risk patients and CPM does not benefit those at high risk.

Preroughening transitions in crystal surfaces and valence-bond phases in quantum spin chains.

Abstract: We show that disordered flat phases in crystal surfaces are equivalent to valence-bond-type phases in integer and half-integer spin quantum chains. In the quantum spin representation the disordered flat phase represents a fluid-type phase with long-range antiferromagnetic spin order. This order is stabilized dynamically by the hopping of the particles and short-range spin-exchange interactions. The mass of N\'eel solitons is finite. Numerical finite-size-scaling results confirm this. We identify the order parameter of the valence-bond phase. The Haldane conjecture suggests a fundamental difference between half-integer and integer antiferromagnetic Heisenberg spin chains. We find that disordered flat phases are realized in both cases, have exactly the same type of long-range antiferromagnetic spin order, and are stabilized by exactly the same mechanism. They differ only in the mathematical formulation of broken symmetry in the spin representation. We suggest experimental methods of observing disordered flat phases in crystal surfaces.