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At least 1,801 records · Page 100Linked to original sources
PubMed1996

Linkage of rheumatoid arthritis to the candidate gene NRAMP1 on 2q35.

The macrophage resistance gene NRAMP1 regulates priming/activation of macrophages for enhanced TNF alpha, IL 1 beta, and MHC class II expression. Since all of these functions are of potential importance in the induction or maintenance or both of autoimmune disease, samples from the Arthritis and Rheumatism Council's repository of multicase rheumatoid arthritis families were typed for a dinucleotide repeat in the NRAMP1 promoter region and four other 2q34 (TNP1) or 2q35 (IL8R, VIL1, DES) marker genes. Identity by descent (IBD) sib pair analysis using a three locus haplotype NRAMP1-IL8RB-VIL1, or NRAMP1 alone, provided preliminary evidence (maximum lod score = 1.01, p = 0.024) for a gene in this region contributing to suceptibility to rheumatoid arthritis. Candidacy for NRAMP1 as the disease susceptibility gene was supported by a significant bias (p = 0.048) towards transmission of the NRAMP1 promoter region allele 3 in affected offspring.

Arthritis, Rheumatoid↗
PubMed2001

Distinct phenotypes distinguish the molecular classes of Angelman syndrome.

BACKGROUND: Angelman syndrome (AS) is a severe neurobehavioural disorder caused by defects in the maternally derived imprinted domain located on 15q11-q13. Most patients acquire AS by one of five mechanisms: (1) a large interstitial deletion of 15q11-q13; (2) paternal uniparental disomy (UPD) of chromosome 15; (3) an imprinting defect (ID); (4) a mutation in the E3 ubiquitin protein ligase gene (UBE3A); or (5) unidentified mechanism(s). All classical patients from these classes exhibit four cardinal features, including severe developmental delay and/or mental retardation, profound speech impairment, a movement and balance disorder, and AS specific behaviour typified by an easily excitable personality with an inappropriately happy affect. In addition, patients can display other characteristics, including microcephaly, hypopigmentation, and seizures. METHODS: We restricted the present study to 104 patients (93 families) with a classical AS phenotype. All of our patients were evaluated for 22 clinical variables including growth parameters, acquisition of motor skills, and history of seizures. In addition, molecular and cytogenetic analyses were used to assign a molecular class (I-V) to each patient for genotype-phenotype correlations. RESULTS: In our patient repository, 22% of our families had normal DNA methylation analyses along 15q11-q13. Of these, 44% of sporadic patients had mutations within UBE3A, the largest percentage found to date. Our data indicate that the five molecular classes can be divided into four phenotypic groups: deletions, UPD and ID patients, UBE3A mutation patients, and subjects with unknown aetiology. Deletion patients are the most severely affected, while UPD and ID patients are the least. Differences in body mass index, head circumference, and seizure activity are the most pronounced among the classes. CONCLUSIONS: Clinically, we were unable to distinguish between UPD and ID patients, suggesting that 15q11-q13 contains the only significant maternally expressed imprinted genes on chromosome 15.

Adult↗
PubMed2002

Lessons from the Australian Patient Safety Foundation: setting up a national patient safety surveillance system--is this the right model?

The evolution of the concepts and processes underpinning the Australian Patient Safety Foundation's systems over the last 15 years are traced. An ideal system should have the following attributes: an independent organisation to coordinate patient safety surveillance; agreed frameworks for patient safety and surveillance systems; common, agreed standards and terminology; a single, clinically useful classification for things that go wrong in health care; a national repository for information covering all of health care from all available sources; mechanisms for setting priorities at local, national and international levels; a just system which caters for the rights of patients, society, and healthcare practitioners and facilities; separate processes for accountability and "systems learnings"; the right to anonymity and legal privilege for reporters; systems for rapid feedback and evidence of action; mechanisms for involving and informing all stakeholders. There are powerful reasons for establishing national systems, for aligning terminology, tools and classification systems internationally, and for rapid dissemination of successful strategies.

Australia↗
PubMed1997

What are hospitals doing about clinical guidelines?

OBJECTIVES: To assess the attitudes of senior hospital staff towards clinical guidelines, and to ascertain the perceived extent and benefits of their local use; to identify those hospitals with current or planned future written strategies for the systematic development of clinical guidelines, and the staff responsible for leading them; and to establish the essential elements of existing strategies, and the methods used to ensure the proper development, dissemination, implementation, and evaluation of local guidelines. DESIGN: Cross sectional survey. PARTICIPANTS: Senior staff of 270 acute hospitals in the United Kingdom (response rate 202/270 (75%)) in 1995. RESULTS: 197/199 (99%) of respondents thought that clinical guidelines were a good idea, and 176/196 (90%) were aware of some guideline activity occurring within their hospitals. The most important benefits of local guideline activity were increased healthcare efficiency and effectiveness, greater consistency of treatment, and team building. 174/194 (90%) of respondents were in favour of the development of a readily accessible national repository of evidence-based clinical guidelines. 38/201 (19%) of respondents had a clinical guidelines strategy and a further 91/201 (45%) said that they had plans to develop one in the near future. The need to improve clinical outcomes was most often reported as the reason for developing a strategy. Medical directors most commonly had formal responsibility to lead the strategy, but someone without formal responsibility ran the operation in half the hospitals. Only 18/36 (50%) of strategies gave advice on the development of guidelines; and only a few strategies made explicit statements on which clinical services to target for guideline development, or the methods to be used for their validation and promotion. Some strategies lacked explicit statements on methods to monitor adherence, routine review, and update of guidelines. Internal literature searches (29/31 (94%)), the use of national guidelines (29/32 (91%)), local consensus conferences (28/32 (88%)), and peer group review (21/24 (88%)) were the most popular methods of validation used in hospitals with a strategy. Methods used to promote the dissemination, implementation, and evaluation of clinical guidelines included clinical audit (31/32 (97%)), peer review (25/30 (83%)), continuing education (23/29 (79%)), targeting of opinion leaders (17/26 (65%)), use of structured case notes (14/31 (45%)), patient mediated interventions (9/26 (35%)), and patient specific reminders (8/26 (31%)). CONCLUSIONS: Most senior hospital staff have a favourable attitude towards clinical guidelines. Most hospitals are undertaking some guideline activity, but few seem to be doing so within a locally agreed hospital wide strategy in which guideline development, dissemination, implementation, and evaluation are systematically considered. Many of the current methods used to validate guidelines locally are inadequate. Evidence-based clinical guidelines should be developed nationally, leaving hospitals to focus their energies on the local adaptation, dissemination, implementation, and evaluation of such guidelines. Only in this way will local guidelines achieve their full potential to improve clinical care and patient outcomes.

Attitude of Health Personnel↗
PubMed2001

Simple sequence repeat analysis of a clonally propagated species: a tool for managing a grape germplasm collection.

The USDA germplasm repositories help to preserve the genetic variability of important crop species by collecting and maintaining representative cultivars and related germplasm. Simple sequence repeat markers with high allelic diversity were used to type 41 grapevines from 40 accessions. All vines were either seedless table grape cultivars or cultivars with names similar to table grape cultivars. The proportion of shared alleles was selected as the most appropriate statistical measure of genetic distance for this population. In conjunction with morphological traits, known synonyms were confirmed and a previously unknown synonym was discovered. An alleged synonym in the literature was disproved by the DNA data. The data were consistent with known parentage, where such data were available. Two mislabeled vines in the USDA collection were identified. UPGMA grouped the cultivars loosely into three groups: a group of nine mostly Middle Eastern cultivars, a group of 22 accessions mostly from Russia and Afghanistan that were morphologically similar to 'Thompson Seedless', and a third very loose group of 11 accessions consisting mostly of eastern European wine grape cultivars. The limitations and usefulness of this type of analysis are discussed.

Alleles↗
PubMed2006

DNA typing and genetic relations among European hazelnut (Corylus avellana L.) cultivars using microsatellite markers.

In this work, 78 hazelnut (Corylus avellana L.) cultivars from various germplasm repositories were studied at 16 simple sequence repeat (SSR) loci in order to identify the genotypes and investigate their genetic relations. Polymorphism at SSR loci was evaluated on the basis of number of alleles (mean: 9.4), expected heterozygosity (mean: 0.78), and power of discrimination (mean: 0.91). Several synonyms reported in the literature were confirmed, and new cases of synonymy were identified. The parentage of North American cultivars 'Butler', 'Ennis', and 'Royal', the French selection 'Fercoril-Corabel', and 'Impératrice Eugenie' was investigated on the basis of the alleles present at 16 loci and analysis at 8 additional loci. A dendrogram generated from cluster analysis using the unweighted pair group method with arithmetic mean grouped cultivars according to their pedigrees or geographical origins. There was an evident differentiation of the northern European cultivars from the southern European ones and from the Turkish cultivars. The latter clustered close to but separate from the Italian and Spanish clusters. It is very likely that exchanges of cultivars occurred between the central and western Mediterranean basin as a result of human migration and trade. A database containing the SSR profiles of the most important hazelnut cultivars will be useful for identification of cultivars and synonyms, legal protection, and parentage analysis.

Cluster Analysis↗
PubMed1997

Occurrence and identification of microorganisms in compacted clay-based buffer material designed for use in a nuclear fuel waste disposal vault.

A full-scale nuclear fuel waste disposal container experiment was carried out 240 m below ground in an underground granitic rock research laboratory in Canada. An electric heater was surrounded by buffer material composed of sand and bentonite clay and provided heat equivalent to what is anticipated in a Canadian nuclear fuel waste repository. During the experiment, the heat caused a mass transport of water and moisture content gradients developed in the buffer ranging from 13% closest to the heater to 23% at the rock wall of the deposition hole. Upon decommissioning after 2.5 years, microorganisms could be cultured from all samples having a moisture content above 15% but not from samples with a moisture content below 15%. Heterotrophic aerobic and anaerobic bacteria were found in numbers ranging from 10(1) to 10(6) cells/g dry weight buffer. Approximately 10(2), or less, sulphate-reducing bacteria and methanogens per gram of dry weight buffer were also found. Identification of buffer population members was performed using Analytical Profile Index (API) strips for isolated bacteria and 16S rRNA gene sequencing for in situ samples. A total of 79 isolates from five buffer layers were identified with API strips as representing the beta, gamma and delta groups of Proteobacteria and Gram-positive bacteria. Sixty-seven 16S rRNA clones that were obtained from three buffer layers were classified into 21 clone groups representing alpha and gamma groups of Proteobacteria, Gram-positive bacteria, and a yeast. Approximately 20% of the population comprised Gram-positive bacteria. Members of the genera Amycolatopsis, Bacillus, and Nocardia predominated. Among Gram-negative bacteria, the genera Acinetobacter and Pseudomonas predominated. Analysis of lipid biomarker signatures and in situ leucine uptake demonstrated that the buffer population was viable. The results suggest that a nuclear fuel waste buffer will be populated by active microorganisms only if the moisture content is above a value where free water is available for active life.

Aluminum Silicates↗
PubMed2002

Mining MEDLINE: abstracts, sentences, or phrases?

A growing body of works address automated mining of biochemical knowledge from digital repositories of scientific literature, such as MEDLINE. Some of these works use abstracts as the unit of text from which to extract facts. Others use sentences for this purpose, while still others use phrases. Here we compare abstracts, sentences, and phrases in MEDLINE using the standard information retrieval performance measures of recall, precision, and effectiveness, for the task of mining interactions among biochemical terms based on term co-occurrence. Results show statistically significant differences that can impact the choice of text unit.

Abstracting and Indexing↗
PubMed2001

A neural network architecture for data classification.

This article aims at showing an architecture of neural networks designed for the classification of data distributed among a high number of classes. A significant gain in the global classification rate can be obtained by using our architecture. This latter is based on a set of several little neural networks, each one discriminating only two classes. The specialization of each neural network simplifies their structure and improves the classification. Moreover, the learning step automatically determines the number of hidden neurons. The discussion is illustrated by tests on databases from the UCI machine learning database repository. The experimental results show that this architecture can achieve a faster learning, simpler neural networks and an improved performance in classification.

Computer Systems↗
PubMed2001

A fast and convergent stochastic MLP learning algorithm.

We propose a stochastic learning algorithm for multilayer perceptrons of linear-threshold function units, which theoretically converges with probability one and experimentally exhibits 100% convergence rate and remarkable speed on parity and classification problems with typical generalization accuracy. For learning the n bit parity function with n hidden units, the algorithm converged on all the trials we tested (n=2 to 12) after 5.8 x 4.1(n) presentations for 0.23 x 4.0(n-6) seconds on a 533MHz Alpha 21164A chip on average, which is five to ten times faster than Levenberg-Marquardt algorithm with restarts. For a medium size classification problem known as Thyroid in UCI repository, the algorithm is faster in speed and comparative in generalization accuracy than the standard backpropagation and Levenberg-Marquardt algorithms.

Algorithms↗
PubMed2003

A hierarchical method for finding optimal architecture and weights using evolutionary least square based learning.

In this paper, we present a novel approach of implementing a combination methodology to find appropriate neural network architecture and weights using an evolutionary least square based algorithm (GALS).1 This paper focuses on aspects such as the heuristics of updating weights using an evolutionary least square based algorithm, finding the number of hidden neurons for a two layer feed forward neural network, the stopping criterion for the algorithm and finally some comparisons of the results with other existing methods for searching optimal or near optimal solution in the multidimensional complex search space comprising the architecture and the weight variables. We explain how the weight updating algorithm using evolutionary least square based approach can be combined with the growing architecture model to find the optimum number of hidden neurons. We also discuss the issues of finding a probabilistic solution space as a starting point for the least square method and address the problems involving fitness breaking. We apply the proposed approach to XOR problem, 10 bit odd parity problem and many real-world benchmark data sets such as handwriting data set from CEDAR, breast cancer and heart disease data sets from UCI ML repository. The comparative results based on classification accuracy and the time complexity are discussed.

Algorithms↗
PubMed2006

ON the influence of parameter theta- on performance of RBF neural networks trained with the dynamic decay adjustment algorithm.

The dynamic decay adjustment (DDA) algorithm is a fast constructive algorithm for training RBF neural networks (RBFNs) and probabilistic neural networks (PNNs). The algorithm has two parameters, namely, theta(+) and theta(-). The papers which introduced DDA argued that those parameters would not heavily influence classification performance and therefore they recommended using always the default values of these parameters. In contrast, this paper shows that smaller values of parameter theta(-) can, for a considerable number of datasets, result in strong improvement in generalization performance. The experiments described here were carried out using twenty benchmark classification datasets from both Proben1 and the UCI repositories. The results show that for eleven of the datasets, the parameter theta(-) strongly influenced classification performance. The influence of theta(-) was also noticeable, although much less, on six of the datasets considered. This paper also compares the performance of RBF-DDA with theta(-) selection with both AdaBoost and Support Vector Machines (SVMs).

Algorithms↗
PubMed1976

The reovirus replicative cycle.

Soon after entry into their host cells ssRNA viruses form doule-stranded replicative intermediates. Most RNA viruses exist only transiently in this double-stranded form. Double-strand formation occurs irrespective of whether the genome is of the same or complementary polarity to viral mRNA. In contrast, reoviruses contain dsRNAs from the outset. Single, and not double, strands are the intracellular intermediates through which genetic information is transferred from parental to progeny reoviruses. Double strands are the repositories in which the information is stored. We emphasize this distinction because it permits dsRNA-containing viruses to replicate conservatively, a mode of replication that is not shared by any other viruses. One important consequence of the conservative mode of replication is that cellular enzymes never gain access to the reovirus genome but only to its ssRNA precursors.

Binding Sites↗
PubMed2004

Central memory and effector memory T cell subsets: function, generation, and maintenance.

The memory T cell pool functions as a dynamic repository of antigen-experienced T lymphocytes that accumulate over the lifetime of the individual. Recent studies indicate that memory T lymphocytes contain distinct populations of central memory (TCM) and effector memory (TEM) cells characterized by distinct homing capacity and effector function. This review addresses the heterogeneity of TCM and TEM, their differentiation stages, and the current models for their generation and maintenance in humans and mice.

Animals↗
PubMed2006

The structural and functional role of RNA in icosahedral virus assembly.

Despite tremendous advances in high-resolution structure determination of virus particles, the organization of encapsidated genomes and their role during assembly are poorly understood. This article summarizes recent insights from structural, biochemical, and genetic analyses of icosahedral viruses that contain single-stranded, positive-sense RNA genomes. X-ray crystallography of several viruses in this category has provided tantalizing glimpses of portions of the packaged nucleic acid, contributing crucial information on how the genome might be folded within the virion. This information combined with theoretical considerations and data from molecular approaches suggests mechanisms by which coat proteins interact with genomic RNA to shape it into a conformation that is compatible with the geometry of the virion. It appears that RNA, in addition to its function as a repository for genetic information, plays an important structural role during assembly and can on occasion override the ability of the coat protein to form a particle with defined icosahedral symmetry.

Models, Molecular↗
PubMed1990

Monitoring and evaluating the quality and appropriateness of angiographic/interventional radiologic procedures.

The safety and efficacy of invasive radiologic procedures should be monitored in all departments that include such activities. Assessing the data arising from such monitoring and taking the actions needed to improve quality and appropriateness of care are additional steps that must be taken to meet the expectations of the JCAHO. The SCVIR has distributed to its membership for comment a proposal for a model program for monitoring and evaluating angiographic/interventional procedures that, if adopted by a department, would help meet external accrediting reviews. The SCVIR also has under study a proposal to develop a national data base that would act as a repository of information on invasive radiologic procedures. By voluntarily participating in the program, departments would receive feedback that periodically documents performance and compares it with national norms established by all participants in the program. If the data base is sufficiently detailed, distinct advantages of collaborative research could result. Data related to comparative technology assessment, cost-benefit analyses, and other derived information could then be made available to other physicians, the public, payers, and government agencies. The discipline of radiology would have a vehicle to influence and create national recommendations for health care policy decisions.

Angiography↗
PubMedDate not supplied

Handheld computers in radiology.

The next phase of the digital revolution in medicine is taking place through the dissemination of powerful handheld computers. Handheld computers, or personal digital assistants (PDAs), are no longer considered either a curiosity or a toy. The current handheld computer has many features (Internet access, simple e-mail client software, spreadsheet and database programs, word processing, and digital media) that make it an ideal tool for healthcare providers. Improvements in handwriting recognition, display characteristics, and wireless networking capabilities provide a platform for real-time review of both large static and dynamic repositories of patient data. Although earlier PDA models lacked the ability to display medical images appropriately, current PDAs boast display characteristics that approach low-resolution computer monitors. Although the handheld computer is not yet a reliable option for soft-copy reading, it offers many features that can improve work flow and efficiency for the radiologist. These features include improved personal information management, decision support via access to educational materials, and remote access to radiology-related information systems.

Computers, Handheld↗
PubMedDate not supplied

Informatics in radiology (infoRAD): integrating MIRC-compliant semiautomated teaching files into PACS work flow.

A Medical Image Resource Center (MIRC)-compliant teaching file system was created that can be integrated into a picture archiving and communication system (PACS) environment. This system models the three-step process necessary for efficient teaching file creation in a PACS environment: (a) identifying and transferring a case quickly and easily during primary interpretation, (b) editing and authoring the case outside of primary interpretation time, and (c) publishing the case locally and via MIRC standard-based mechanisms. Images from interesting cases are e-mailed to the teaching file system from either the PACS workstation or the radiologist's personal computer. Notes and clinical information may be included in the e-mail text to prompt the recollection of case details. Images are automatically extracted from the e-mail and sent to an image repository, and text fields are captured in a database. The World Wide Web-based authoring component provides tools for final authoring of cases and for the manipulation of existing cases. Authors designate access levels for each case, which is then made available locally and, potentially, to the entire MIRC-compliant community. Although this application has not yet been implemented as a departmental solution, it promises to improve and streamline medical education and promote better patient care.

Radiology↗

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