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At least 415 records · Page 23Linked to original sources
PubMed2003

Database-driven computerized antibiotic decision support: novel use of expert antibiotic susceptibility rules embedded in a pathogen-antibiotic logic matrix.

To better serve an antibiotic guidance program, we hypothesized that the relatively few antibiotic susceptibility measurements conducted in the microbiology laboratory could be extended to predict antibiotic susceptibilities for all antibiotics on the hospital formulary using expert infectious disease logic. With the assistance of infectious disease specialists, we developed these logic rules and then applied them to 26,196 unique patient culture specimens and the accompanying 334,131 antibiotic susceptibility measurements generating 804,809 additional predicted bug-drug susceptibility data points. From the resulting data set, the antibiotic susceptibility profile for one pathogen, Streptococcus pneumoniae, is highlighted herein. We then incorporated the extended susceptibility profiles into a computerized antibiotic guidance program that matches current patients of interest with the positive cultures from past similar patients and calculates predicted effective antibiotic therapy. We conclude that this method successfully derives antibiotic predictions and merits further testing to evaluate its potential use in the hospital environment.

Anti-Bacterial Agents↗
PubMed2004

Pathway logic modeling of protein functional domains in signal transduction.

Protein functional domains (PFDs) are consensus sequences within signaling molecules that recognize and assemble other signaling components into complexes. Here we describe the application of an approach called Pathway Logic to the symbolic modeling signal transduction networks at the level of PFDs. These models are developed using Maude, a symbolic language founded on rewriting logic. Models can be queried (analyzed) using the execution, search and model-checking tools of Maude. We show how signal transduction processes can be modeled using Maude at very different levels of abstraction involving either an overall state of a protein or its PFDs and their interactions. The key insight for the latter is our algebraic representation of binding interactions as a graph.

Computational Biology↗
PubMed2004

Communicating the logic of a treatment plan formulated in Asbru to domain experts.

This paper presents an interactive visualization for medical treatment plans that are formulated in the plan representation language Asbru. So far, most attention of the protocol-based care community was focused towards formal guideline representation and authoring partly supported by graphical tools. The intention of this work is to go the opposite way and communicate the logic of a computerized treatment plan to physicians, nursing-, and other medical personnel visually. The visualization is based on the idea of flow-chart algorithms widely used in medical education and practice. This concept has been extended in order to cope with the powerful and expressive guideline representation language Asbru. Furthermore, a number of interactive navigational and overview extensions are used to intuitively support the understanding of the logic of plans. The user-centered development approach applied for these interactive visualization methods has been guided by user input gathered via a user study, design reviews, and prototype evaluations as described in this document.

Algorithms↗
PubMed2004

A description logics approach to CGPS.

We develop a formal framework by which clinical guidelines and protocols (CGPs) can be partially represented as a set of terminological concept definitions using standard description logics. There are two benefits in pursuing such an approach. First, it provides a foundation for logic-based CGP fusion and collision detection. Second, it allows for the checking of clinical treatment episodes from the EPR against CGPs.

Artificial Intelligence↗
PubMed1990

Fuzzy Logic for medical expert systems.

The use of linguistic approximation enables knowledge to be represented in a more meaningful way and this is especially important in medical domain as it involves a lot of subjective decision making; Fuzzy Logic, introduced by Zadeh, has the ability to represent this imprecise expression. In this paper, an alternative approach of Fuzzy Logic in handling the approximate reasoning in expert systems will be described. The approach does not use the General Modus Ponen on the compositional rule of inference, but instead it uses a collection of rules to specify the properties of the inference (in making decision). An example of medical domain is described as its application.

Diagnosis, Computer-Assisted↗
PubMedDate not supplied

The myocardial microangiopathy in human and experimental diabetes mellitus. (A microscopic, ultrastructural, morphometric and computer-assisted symbolic-logic analysis).

The following microscopical aspects were found in the small intramural arteries in the myocardium of 30 diabetic patients: endothelial proliferations with focal protuberances leading to partial narrowing of the lumen, increased thickness of the arterial wall due to fibrosis and accumulations of neutral mucopolysaccharides: alteration of elastic fibres. Morphometrically, the arterial wall thickness and the arterial diameter were increased whereas the arterial density decreased in the diabetic heart. In 25 rats with streptozotocin-induced diabetes the small intramyocardial arteries were investigated at 11 to 40 weeks of diabetic state. Using morphometrical analysis a constant increase of arterial wall thickness paralleling the diabetes duration was found. Microscopically, the lesions consist in endothelial proliferation with bridging across the vascular lumen and slight perivascular and diffuse fibrosis. Ultrastructurally, the capillary basal lamina was thickened in the diabetic myocardium. In order to investigate the morphometrical data we used symbolic-logic as a decision method, by applying an original computer program based on the Quine-McCluskey algorithm. All our results together with the final symbolic-logic expression suggest that damage of the small intramyocardial arteries plays an important role in the pathogenesis of diabetic cardiomyopathy.

Aged↗
PubMed1995

Aneuploidy occurrence in human tumours: a logical-automaton approach.

The search for new, reliable factors of prognosis in cancerology is sadly deficient at the present moment. Of these factors, the measurement of ploidy gives rise to considerable hope. Nevertheless, despite the impressive number of papers currently published, no general law seems to be emerging that associates the ploidy rate of a tumour with its clinical evolution in a patient. The purpose of the present work is firstly to use a logical automation to describe the cell cycle in terms of binary variables (the validation of the methodology), and secondly to demonstrate that a certain 'cancer logic' can be distilled, at least with respect to the genesis of DNA histograms among tumours.

Aneuploidy↗
PubMed1996

[Renal artery obstruction: from experimental models to logical approach to diagnosis and treatment].

Renovascular hypertension is a syndrome for which, historically, the description of the pathophysiological model in animals preceded the clinical description in human patients. These models allow to understand the local paracrine and systemic endocrine role of the renin-angiotensin system. Whatever the method used to induce renovascular hypertension, the model goes through an initial stage of renin-angiotensin activation, which is followed sooner or later by retention of salt and water. The logical approach to the diagnosis and treatment of renovascular hypertension in man proceeds from this experimental pathophysiological description. The diagnosis establishes a relationship between the stenosis of the renal artery, the systemic arterial hypertension associated with its consequences on the target organs, particularly the kidney downstream to the stenosis (ischaemia) and the contralateral kidney exposed to hypertension, and the high levels of circulating renin and angiotensin (nephro-angiosclerosis). The diagnosis involves a systemic and separate approach to the endocrine and excretory functions of the kidney under basal conditions and after acute blockade of the renin-angiotensin system. Therapeutic indications also proceed from similar logical pathophysiological approaches.

Animals↗
PubMed1998

[Consultation service for efficacious usage of laboratory tests based on logical reasoning and evidence].

To effectively respond to the desire for consultation in clinical practice, we must prepare logical reasoning and evidence which rationally supports laboratory test selection, the interpretation of test results and recommendation of certain tests to physicians. Standard of medical decision making can be used for logic issues such as posttest probability, test characteristics and receiver operating characteristics (ROC) curves and establishing appropriate cut-off points. Although we usually obtain evidence by consulting authorities or the literature, good evidence can also be obtained from meta-analysis. In addition, we can demonstrate the relationship of laboratory tests among several frequently occurring diseases and epidemiological tendencies such as frequency of causative organisms at several infection sites and bacterial sensitivities to antimicrobial agents, because we have access to a large-scale laboratory database. To construct a well-organized knowledge base with explicit evidence, cooperation among many facilities is necessary to develop system, which allows the free exchange of data.

Artificial Intelligence↗
PubMed1978

Intermingling and disordered logic as influences on schizophrenic 'thought disorders'.

A technique was devised to elicit bizarre or idiosyncratic responses from 30 young schizophrenics, who were then re-interviewed a week later to determine the reasons for each patient's idiosyncratic verbalizations. Taped interviews of the schizophrenics, scored along a series of rating scales, indicated: (1) An overt mechanism involved in bizarre schizophrenic language is a tendency to intermingle into their responses material from their current and past experiences. (2) Careful analysis suggests that the seemingly bizarre intermingled material of schizophrenics usually is close to the original "correct" topic. (3) The bizarre intermingled material is related to the patients' personal lives. (4) The intermingled material does not usually represent a failure to screen out or repress primitive drive dominated sexual or aggressive material. (5) Disordered logic was not a major factor in accounting for bizarre schizophrenic language.

Adult↗
PubMed2003

Increased predictive value of parameters by fuzzy logic-based multiparameter analysis.

BACKGROUND: A recent study on postoperative effusions and edema was used to demonstrate the potential of fuzzy techniques in multiparameter data analysis. In this study, more than 50 parameters of 75 patients were collected and examined for correlations between some of the parameters and the later development of complications. METHODS: We employed a rule-based fuzzy-logic system in order to combine the diagnostic values of single parameters. The advantage of fuzzy sets is that they substitute sharp cut-off values with a smooth transition from one property to another. Therefore, there is no decision of "either-or" but rather a graded assessment of "more or less", which is often more suitable for a problem. RESULTS: The fuzzy combination of parameters led to a large increase of sensitivity and specificity when compared with the best single parameter. This increase was achieved by taking a close look at the parameters. A newly created parameter, relative weight, turned out to be very powerful. CONCLUSIONS: Fuzzy techniques can increase the discriminating power of classical statistical tools. In addition, results obtained by fuzzy analysis are highly interpretable. A combination of the CLASSIF1 algorithm for the identification of the most relevant parameters, followed by fuzzy analysis, represents a powerful tool for the handling of large amounts of multiparameter data.

Adolescent↗
PubMedDate not supplied

A probability-based aid for teaching medical students a logical approach to diagnosis.

In this paper we present a method of teaching medical students a logical approach to diagnosis. By using the independent Bayes method, commonly employed in decision aids, students can be made aware of how information on each new symptom affects what is likely in the light of what is known already. This approach is used for the diagnosis of thoracic symptoms in patients with normal chest X-rays and an example is given. Extensions of the system to incorporate information from investigations and error costs are discussed.

Diagnosis↗
PubMed1994

Quantitative structure-activity relationships by neural networks and inductive logic programming. I. The inhibition of dihydrofolate reductase by pyrimidines.

Neural networks and inductive logic programming (ILP) have been compared to linear regression for modelling the QSAR of the inhibition of E. coli dihydrofolate reductase (DHFR) by 2,4-diamino-5-(substituted benzyl)pyrimidines, and, in the subsequent paper [Hirst, J.D., King, R.D. and Sternberg, M.J.E. J. Comput.-Aided Mol. Design, 8 (1994) 421], the inhibition of rodent DHFR by 2,4-diamino-6,6-dimethyl-5-phenyl-dihydrotriazines. Cross-validation trials provide a statistically rigorous assessment of the predictive capabilities of the methods, with training and testing data selected randomly and all the methods developed using identical training data. For the ILP analysis, molecules are represented by attributes other than Hansch parameters. Neural networks and ILP perform better than linear regression using the attribute representation, but the difference is not statistically significant. The major benefit from the ILP analysis is the formulation of understandable rules relating the activity of the inhibitors to their chemical structure.

Animals↗
PubMed1994

Quantitative structure-activity relationships by neural networks and inductive logic programming. II. The inhibition of dihydrofolate reductase by triazines.

One of the largest available data sets for developing a quantitative structure-activity relationship (QSAR)--the inhibition of dihydrofolate reductase (DHFR) by 2,4-diamino-6,6-dimethyl-5-phenyl-dihydrotriazine derivatives--has been used for a sixfold cross-validation trial of neural networks, inductive logic programming (ILP) and linear regression. No statistically significant difference was found between the predictive capabilities of the methods. However, the representation of molecules by attributes, which is integral to the ILP approach, provides understandable rules about drug-receptor interactions.

Animals↗
PubMed2002

Integrating fuzzy logic, optimization, and GIS for ecological impact assessments.

Appraisal of ecological impacts has been problematic because of the behavior of ecological system and the responses of these systems to human intervention are far from fully understood. While it has been relatively easy to itemize the potential ecological impacts, it has been difficult to arrive at accurate predictions of how these impacts affect populations, communities, or ecosystems. Furthermore, the spatial heterogeneity of ecological systems has been overlooked because its examination is practically impossible through matrix techniques, the most commonly used impact assessment approach. Besides, the public has become increasingly aware of the importance of the EIA in decision-making and thus the interpretation of impact significance is complicated further by the different value judgments of stakeholders. Moreover, impact assessments are carried out with a minimum of data, high uncertainty, and poor conceptual understanding. Hence, the evaluation of ecological impacts entails the integration of subjective and often conflicting judgments from a variety of experts and stakeholders. The purpose of this paper is to present an environmental impact assessment approach based on the integration fuzzy logic, geographical information systems and optimization techniques. This approach enables environmental analysts to deal with the intrinsic imprecision and ambiguity associated with the judgments of experts and stakeholders, the description of ecological systems, and the prediction of ecological impacts. The application of this approach is illustrated through an example, which shows how consensus about impact mitigation can be attained within a conflict resolution framework.

Decision Making↗
PubMed2002

Accuracy of neuro-fuzzy logic and regression calculations in determining maximal lactate steady-state power output from incremental tests in humans.

The aim of this study was to employ neuro-fuzzy logic and regression calculations to determine the accuracy of prediction of the power output ( P) of the maximal lactate steady-state (MLSS) on a cycle ergometer calculated from the results of incremental tests. A group of 17 male and 17 female sports students underwent two incremental tests (a 1 min test T(1): initial exercise intensity 0.2 W x kg(-1) increasing 0.2 W x kg(-1) every minute; a 3 min test T(3): initial exercise intensity 0.6 W x kg(-1) increasing 0.6 W x kg(-1) every 3 min) and at least four constant-intensity tests of 30 min duration. Two models for MLSS calculation were developed using the data from T(1) and T(3), a forward stepwise linear regression model (REG) and a neuro-fuzzy model (FUZ). A group of 26 randomly selected subjects (model group, MG) were used to generate the REG and the FUZ models. The data from the remaining 8 subjects (4 men and 4 women; verifying group, VG) were used to verify the REG and FUZ models. The precision of the MLSS calculation in MG produced a better correlation when using data from T(1) (REG r=0.95, FUZ r=0.99) than data from T(3) (REG r=0.88, FUZ r=0.98). Our calculation models were confirmed using data from VG for T(1) (REG r=0.97, FUZ r=0.98) as well as for T(3) (REG r=0.97, FUZ r=0.97). Based on our subject population of young, healthy sport students, our results suggest that a single incremental test may be used for prediction of P at the MLSS using a cycle ergometer. Furthermore, the results from T(1) yielded higher correlations compared to T(3). Calculations from REG were similar to FUZ but the precision of REG and FUZ was better compared to calculations derived using data from a single threshold.

Adult↗
PubMed2004

Determination of fuzzy logic membership functions using genetic algorithms: application to structure-odor modeling.

Fuzzy logic has been used as a tool in structure-camphoraceous odor relationships. The data base studied included 99 molecules. The rules used to discriminate between camphor and non camphor molecules lead to 77% correct discrimination. Such rules account for the shape and the size of the molecule. Their adjustment by means of genetic algorithms led to 84% correct discrimination between camphor and non-camphor molecules. [figure: see text]. Membership function for the chosen variables.

Algorithms↗