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PubMed2004

Patient control and end-of-life care part II: the advanced practice nurse perspective.

PURPOSE/OBJECTIVES: To explore the nature of what people with advanced cancer want regarding personal control and comfort at the end of life. RESEARCH APPROACH: Descriptive, naturalistic, using Denzins model of interpretive interactionism. SETTING: A variety of urban and rural communities throughout the state of Texas. PARTICIPANTS: 7 people with advanced cancer diagnoses. METHODOLOGIC APPROACH: Participants were recruited via oncology advanced practice nurses who also participated in the study. Interviews were recorded on audiotape and analyzed via Denzins interpretive process of data analysis. MAIN RESEARCH VARIABLES: Patient control. FINDINGS: Thematic analysis revealed six themes: protection of dignity, control of pain and other symptoms associated with disease, management of treatment, management of how remaining time is spent, management of impact on family, and control over the dying process. CONCLUSIONS: Participants expressed a wide variety of preferences for personal control and comfort. Their desires reflected personal values and beliefs about how they spend their time and how they want control over their care. INTERPRETATION: Nurses must be sensitive to the variety of preferences their patients with advanced cancer may have for engagement in decisions regarding treatment, care management, and activities of daily life.

Adult↗

PubMed2001

Networking, coping, and communicating about a medical crisis: a phenomenological inquiry of transplant recipient communication.

Through a phenomenological framework, the authors attempt to shed light on the communication processes of organ transplant recipients when discussing transplantation and related topics. Eight essential themes (awareness, support, commitment, pride, education, mentoring, comparison, and community) emerged from 37 participants as central to the communicative experiences of transplant recipients and their families. Additional insight was generated through a 2nd tier of focus group discussions resulting in a proposed model of transplant recipient communication. An interpretation of the model, implications for future research, and implications for praxis are presented.

Adaptation, Psychological↗

PubMed1984

A comparison of pressure-volume models in hydrocephalus.

Traditional descriptions of the pressure-volume properties of the craniospinal axis have expressed pressure as a function of volume. This study develops a theoretical and practical rationale for expressing volume as a function of pressure. We tested the rationale by comparing the two functions using pressure and volume data collected from 37 hydrocephalic patients during ventricular fluid removal. Two equivalent expressions were evaluated, one expressing pressure as an exponential function of volume and one relating volume as an exponential function of pressure. Each expression had three parameters, adjustable to the specific case. We used a nonlinear curve-fitting algorithm to determine the best estimate of the parameters. We could fit three-parameter exponential functions of either type to the data in all cases. We found a superior goodness-of-fit to aggregated data when expressing volume as a three-parameter exponential function of pressure changes. This finding is discussed in the context of the preferable number of parameters in a model and the interpretation of the terms in the models. This "reversed" volume-pressure relationship has importance in the development of more complicated models involving these same relationships.

Computers↗

PubMed1994

Parameter variability and the interpretation of physiologically based pharmacokinetic modeling results.

For the past several years we have been working with models of benzene distribution and metabolism, principally in the rat, but more recently in humans. Our biologically related objectives have been primarily to assist our laboratory-based colleagues in their quest for understanding of the mechanisms by which benzene exerts its toxic action. A secondary goal has been to develop or adapt models useful in risk assessment applications. We have also had methodological goals that relate to applications of sensitivity analysis on the one hand, but more fundamentally to the connection between experimental data and model structure and parameterization. This paper presents an overview of our work in these areas.

Animals↗

PubMed1999

Intercomparison of retrospective radon detectors.

We performed both a laboratory and a field intercomparison of two novel glass-based retrospective radon detectors previously used in major radon case-control studies performed in Missouri and Iowa. The new detectors estimate retrospective residential radon exposure from the accumulation of a long-lived radon decay product, (210)Pb, in glass. The detectors use track registration material in direct contact with glass surfaces to measure the alpha-emission of a (210)Pb-decay product, (210)Po. The detector's track density generation rate (tracks per square centimeter per hour) is proportional to the surface alpha-activity. In the absence of other strong sources of alpha-emission in the glass, the implanted surface alpha-activity should be proportional to the accumulated (210)Po, and hence to the cumulative radon gas exposure. The goals of the intercomparison were to a) perform collocated measurements using two different glass-based retrospective radon detectors in a controlled laboratory environment to compare their relative response to implanted polonium in the absence of environmental variation, b) perform collocated measurements using two different retrospective radon progeny detectors in a variety of residential settings to compare their detection of glass-implanted polonium activities, and c) examine the correlation between track density rates and contemporary radon gas concentrations. The laboratory results suggested that the materials and methods used by the studies produced similar track densities in detectors exposed to the same implanted (210)Po activity. The field phase of the intercomparison found excellent agreement between the track density rates for the two types of retrospective detectors. The correlation between the track density rates and direct contemporary radon concentration measurements was relatively high, considering that no adjustments were performed to account for either the residential depositional environment or glass surface type. Preliminary comparisons of the models used to translate track rate densities to average long-term radon concentrations differ between the two studies. Further calibration of the retrospective detectors' models for interpretation of track rate density may allow the pooling of studies that use glass-based retrospective radon detectors to determine historic residential radon exposures.

Carcinogens, Environmental↗

PubMed1992

Anisotropy in an ambiguous kinetic depth effect.

A set of animated stimuli (Lissajous figures), each element of which is physically consistent with two different three-dimensional shapes undergoing rigid rotations about orthogonal axes, is described. Human observers typically show a preference for one shape or the other; this preference may be biased by manipulating various parameters of the stimulus. Fairly good predictions of which shape will be seen are made by using an adaptation of Hildreth's smoothest-velocity-field computation. When a given stimulus is rotated 90 degrees in the picture plane, the resolution of the ambiguity is often different, demonstrating anisotropy in the processing of the figures. The nature of this bias is such that for certain figures subjects see a three-dimensional object rotating about a vertical axis regardless of which two-dimensional orientation is used to present the stimulus. This bias is not predicted by the Hildreth model. One interpretation of the results is that the ambiguity in two-dimensional visual motion (i.e., the aperture problem) is not resolved before the interpretation of the three-dimensional structure.

Anisotropy↗

PubMed2004

Online retrieval, processing, and visualization of primate connectivity data from the CoCoMac database.

Connectivity is the key to understanding distributed and cooperative brain functions. Detailed and comprehensive data on large-scale connectivity between primate brain areas have been collated systematically from published reports of experimental tracing studies. Although the majority of the data have been made easily available for online retrieval, the multiplicity of brain maps and the precise requirements of anatomical naming limit the intuitive access to the data. The quality of data retrieval can be improved by observing a small set of conventions in data representation. Standardized interfaces open up further opportunities for automated search and retrieval, for flexible visualization of data, and for interoperability with other databases. This article provides a discussion and examples in text and image of the capabilities of the online interface to the CoCoMac database of primate connectivity. These serve to point out sources of potential confusion and failure, and to demonstrate the automated interfacing with other neuroinformatics resources that facilitate selection and processing of connectivity data, for example, for computational modelling and interpretation of functional imaging studies.

Animals↗

PubMed1997

Weapon carrying among black adolescents: a social network perspective.

OBJECTIVES: This report describes the salience of social networks to the phenomena of adolescent weapon carrying. METHODS: A random-walk network sampling design was used to survey 113 adolescents about topics, including weapon carrying. RESULTS: In a probability sample of 12- to 15-year-olds, 20.9% reported ever carrying a weapon. Carriers were eight times as likely as noncarriers to report weapon carrying by an older associate, and 19 times as likely to report weapon carrying by a peer. A significant dose-response effect was present. CONCLUSIONS: This evidence supports the interpretation that modeling of weapon carrying by personal network members is important for its initiation and maintenance in adolescence.

Adolescent↗

PubMedDate not supplied

Uncertainty assessment of the model RICEWQ in northern Italy.

Model predictions are often seriously affected by uncertainties arising from many sources. Ignoring the uncertainty associated with model predictions may result in misleading interpretations when the model is used by a decision-maker for risk assessment. In this paper, an analysis of uncertainty was performed to estimate the uncertainty of model predictions and to screen out crucial variables using a Monte Carlo stochastic approach and a number of statistical methods, including ANOVA and stepwise multiple regression. The model studied was RICEWQ (Version 1.6.1), which was used to forecast pesticide fate in paddy fields. The results demonstrated that the paddy runoff concentration predicted by RICEWQ was in agreement with field measurements and the model can be applied to simulate pesticide fate at field scale. Model uncertainty was acceptable, runoff predictions conformed to a log-normal distribution with a short right tail, and predictions were reliable at field scale due to the narrow spread of uncertainty distribution. The main contribution of input variables to model uncertainty resulted from spatial (sediment-water partition coefficient and mixing depth to allow direct partitioning to bed) and management (time and rate of application) parameters, and weather conditions. Therefore, these crucial parameters should be carefully parameterized or precisely determined in each site-specific paddy field before the application of the model, since small errors of these parameters may induce large uncertainty of model outputs.

Forecasting↗

PubMed1997

Control and the elderly: "goodness-of-fit".

The present study is an investigation of the effects of person-environment fit on control in an elderly population. Person-environment fit theory predicts that a fit or a match between the characteristics of the person and the characteristic of the environment is important in determining positive outcomes. In the present study, a measure of the misfit (i.e., the mismatch) between an individual's perceptions of control and that individual's desire for control was used to predict life satisfaction, depression, and self-reported health. The misfit between these constructs was found to be a significant predictor of depression, suggesting that a person-environment fit model may be important in explaining this outcome variable. In contrast to the hypothesis, misfit did not significantly predict life satisfaction, and only approached significance in the physical health model. Possible interpretations and implications of these findings were discussed, and potential future research directions were suggested.

Aged↗

PubMed1997

Structuring of perceived interrelations among life events for college students.

We attempted to structure a student's perceived interrelationships among major life events in an hierarchy by the use of the Interpretive Structural Modeling (ISM) method from paired-comparison data. Analysis suggested that, although the perception of the ages at which an individual will experience major life events is strongly influenced by age norm and is less variant among persons, the perception of the interrelationships among life events is more variant.

Adult↗

PubMed2003

Visuospatial dysfunction in the neurodegenerative diseases.

Visuospatial dysfunction is not generally considered a cardinal feature of the common neurodegenerative disorders of late life like Alzheimer's disease (AD), Parkinson's disease (PD), and Dementia with Lewy bodies (DLB). However, a large number of research studies have shown visually related disorders to be surprisingly pervasive among these disease states. Broader recognition of the problems is hindered by a complex literature, which suffers from a lack of uniform definitions of what constitutes "visuospatial" dysfunction and few commonly accepted theoretical models for interpreting results. The interface between visual-spatial function and other variably-defined constructs such as attention and executive function further complicates experimental approaches to this construct. Nonetheless, this review addresses both theoretical and practical issues regarding the presence, importance, and correlates of visual dysfunction associated with neurodegeneration. In addition, the functional impact of the deficits is addressed.

Humans↗

PubMed1997

Dimensions of the Dental Fear Survey among patients with dental phobia.

The aims of this study were to analyze and assess dimensions of the Dental Fear Survey (DFS), which has been developed to measure dental fears and phobias. The present study of 313 dental-phobic individuals analyzed the DFS in a factor analysis using an exploratory (EFA) and a confirmatory (CFA) factor analysis to show dimensions and latent variables. The EFA showed a five-factor structure, with dimensions including items characterizing 'Avoidance of dental care', 'Physiologic arousal during dental treatment', 'Anticipatory anxiety while waiting for dental treatment', 'Fear of the injection needle', and 'Fear of the drill'. The total explained variance of the EFA was 63%. Although statistically significant, the CFA model showed a factor structure with 6 latent variables including a general dental fear factor loading on all 20 items together with the aforementioned 5 factors. In spite of the limitation in sample size and the significant test statistic for this 6-factor structure, the model was interpretable in its dimensionality. In conclusion, these factor analyses have shown a different factor structure of the DFS in this sample of dental-phobic individuals as compared with the dimensions reported from previous research in samples representing nonclinical populations.

Adult↗

PubMed1996

No difference between micro- and macroprolactinomas in the prolactin responsiveness to metoclopramide and dopamine administration.

Differences between micro- and macroprolactinomas, as regards the prolactin secretory pattern in response to pharmacological challenges, have been reported in in vivo and in vitro models, and interpreted as being due to different dopaminergic regulation of prolactin release. In 32 patients with prolactin-secreting tumors, 19 with microprolactinomas and 13 with macroprolactinomas, and ten healthy volunteers, we evaluated the prolactin secretion in response to pharmacological manipulations of central dopaminergic tone. To this end, three tests were performed, in random order: (1) 4-h saline infusion; (2) 10 mg metoclopramide as i.v. bolus; (3) 4-h dopamine infusion (0.01 microgram/kg/min) with a 10-mg metoclopramide bolus given after the second hour of infusion. Dopamine infusion, compared to saline, caused a significant prolactin decrease in all the three groups of subjects, without significant difference between micro- and macroprolactinoma patients. In prolactinoma patients, administration of metoclopramide induced a significant rise in plasma prolactin which, however, was significantly lower than the one displayed by controls. Again, no difference was observed between the two groups of hyperprolactinemic patients. Dopamine infusion induced a significant and comparable increase in the prolactin response to metoclopramide in micro- and macroprolactinoma patients, while it was ineffective in control subjects. In conclusion, no differences appear to exist between micro- and macroprolactinoma patients as regards the prolactin secretory pattern during pharmacological modifications of the dopaminergic tone. A central dopaminergic defect and an increased prolactin turnover with attendant reduction of the intracellular hormone pool may both be involved in the reduced prolactin release following provocative stimuli in patients with prolactinoma.

Adolescent↗

PubMed1985

Deterioration of auditory evoked potentials during cerebellopontine angle manipulations. An interpretation based on an experimental model in dogs.

Evoked action potentials from the internal auditory meatus portion of the cochlear nerve (IAM-EAP's) and brain-stem auditory evoked potentials (BAEP's) from the vertex were simultaneously recorded during cerebellopontine angle (CPA) manipulations (retractions of the cerebellar hemisphere and the cochlear nerve) in dogs. The BAEP changes noted in these dogs were the same as those seen in patients. The IAM-EAP's showed graded deterioration related to BAEP changes. The results are as follows: Prolongation of the I-V interpeak latency of BAEP's, the most common finding during CPA manipulations, is the reflection of prolongation of the I-II interpeak latency, which is caused by conduction impairment or block of the nerve impulses between the extracranial portion of the cochlear nerve and the brain stem. The operative manipulations representing stretch or compression injury to the cochlear nerve in the CPA leads to an acute traumatic cranial nerve root lesion--a retrocochlear lesion. The obliteration of all BAEP components including wave I cannot be caused by conduction block. This is caused by occlusion of the internal auditory artery. Wave I of the BAEP's and the P1-N1 complex of the IAM-EAP's are important indicators of cochlear blood flow during surgical intervention. As possible causes of internal auditory artery obstruction, mechanical distortion of the relationship between the anterior inferior cerebellar artery (AICA) and the internal auditory artery at the junctional portion, mechanical vasospasm of the AICA-internal auditory artery complex, and ensuing no-reflow phenomena are discussed. Evoked action potentials are expected to be a useful intraoperative real-time monitor during CPA surgery that can detect rapid changes derived from cochlear artery insufficency. The real-time aspects can overcome some of the disadvantages of BAEP monitoring.

Animals↗

PubMed1991

A multivariate representation and analysis of DNA sequence data.

A new way to represent and analyze DNA sequence data is described. This approach complements methods currently used, in that it allows the systematic part of the variation between different sequences to be modeled. This can prove as informative as absence of variation (homology), which is the most widely used criterion for comparing sequence data. A multivariate sequence-activity model (SAM), for DNA-promoter sequences is presented, by which the relative promoter strength is modeled in terms of the primary DNA-sequence. The model is shown to have a good predictive capability. The coefficients from the model are interpreted, and used to design new structures predicted to be strong promoters in the system investigated. The approach described is also applicable to other kinds of sequence data, e.g. RNAs, proteins or peptides.

Base Sequence↗

PubMed2026

Hospital transmission of methicillin-resistant Staphylococcus aureus driven by addictive mupA plasmids.

BACKGROUND: Resistance to mupirocin, a cornerstone of Staphylococcus aureus decolonization, is a recognized cause of decolonization failure. Its role in hospital transmission is unknown. METHODS: We conducted genomic surveillance of >10,000 S. aureus isolates from adult patients at two urban hospitals where mupirocin decolonization is routine. Bacterial phenotypes and fitness were evaluated in vitro and in murine colonization models to interpret surveillance results. RESULTS: Genome sequencing identified 475 hospital transmission events; conventional surveillance detected none. The plasmid-mediated resistance determinant mupA ( ileS2 ) was enriched eightfold in methicillin-resistant S. aureus (MRSA) relative to methicillin-susceptible strains. mupA was associated with nearly threefold greater hospital transmission, especially within healthcare-associated MRSA lineages. Surprisingly, multiple independently evolved inactivating mutations in the essential chromosomal gene ileS1 co-occurred with mupA , creating plasmid addiction in which mupA became indispensable for bacterial survival. Plasmid carriage activated the stringent response and reduced colonization fitness, but also conferred collateral tolerance to disinfectants such as ethanol and peroxide. Although addiction further reduced S. aureus fitness, it increased plasmid transfer, promoting spread despite these costs. Unexpectedly, we found a mupirocin-dependent vulnerability to isoleucine limitation, revealing a potential strategy to target mupA -mediated resistance. CONCLUSIONS: Hospital transmission of mupirocin-resistant MRSA is promoted by plasmids that create an evolutionary trap in which mupirocin use selects for bacterial dependence on costly resistance elements. These findings suggest that reducing mupirocin use alone is unlikely to eliminate resistance, underscore the need for genomic surveillance and resistance testing, and provide a framework for strategies to preserve mupirocin effectiveness. MAJOR POINT: This work shows that mupirocin resistance promotes hospital transmission of MRSA, identifies a previously unappreciated mechanism of plasmid addiction, and exposes a collateral vulnerability. These findings underscore the need for genomic surveillance and provide a framework to preserve mupirocin effectiveness.

Journal Article↗

PubMed1999

[Factors that affect DNA content analysis by flow cytometry].

DNA ploidy and cell cycle analysis by flow cytometry is used to obtain additional information about the diagnosis and prognosis of different types of cancer. However, there are several disagreements among authors about the tissue source (fresh-frozen or paraffin embedded), cellular dissociation methods (mechanical, enzymatic or other), use of different dyes, lasers, analysis software with different mathematical models and interpretation of results. A discussion about the different aspects that affect the study of DNA ploidy and cell cycle and a consensus in publications is mandatory. A strict control of analysis processes and data interpretation is also necessary.

Cell Cycle↗