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PubMed1997

Ileal pouches: adaptation and inflammation.

Ileal pouch-anal anastomosis (IPAA) has become the operation of choice following proctocolectomy for ulcerative colitis (UC) and familial adenomatous polyposis. Functioning ileal pouch mucosa undergoes histological changes resembling the colon (colonic metaplasia). The possible role of stasis and luminal factors--bile acids, short-chain fatty acids and bacteria--are discussed. It seems likely that colonic metaplasia is an adaptive response to the new luminal environment in IPAA. Inflammation in the ileal reservoir ('pouchitis') is the most significant late complication in IPAA. It occurs in 20-30% of patients and is virtually confined to those with prior UC. The clinical picture in pouchitis is highly variable; however, it can be easily categorized into three groups. Nevertheless, in most cases it is likely to represent recurrent UC in the ileal pouch. Current treatments and possible preventative strategies for pouchitis have been outlined.

Colectomy↗
PubMed2002

The amazing adventures of robotrat.

By using electrical brain stimulation to deliver both 'virtual' tactile cues and rewards to freely roaming rats, Talwar et al. have been able to instruct animals remotely to navigate through complex mazes and natural environments they have never visited before. These results provide both an elegant alternative way to train animals and a new approach to study basic neurophysiological principles of animal navigation.

Journal Article↗
PubMed2005

El Camino Hospital: using health information technology to promote patient safety.

BACKGROUND: El Camino Hospital is a leader in the use of health information technology to promote patient safety, including bar coding, computerized order entry, electronic medical records, and wireless communications. OVERALL APPROACH TO QUALITY AND SAFETY: Each year, El Camino Hospital's board of directors sets performance expectations for the chief executive officer, which are tied to achievement of local, regional, and national safety and quality standards, including the six Institute of Medicine quality dimensions. He then determines a set of explicit quality goals and measurable actions, which serve as guidelines for the overall hospital. The goals and progress reports are widely shared with employees, medical staff, patients and families, and the public. ADDRESSING THE SIX IOM QUALITY AIMS: For safety, for example, the medication error reduction team tracks and reviews medication error rates. The hospital has virtually eliminated transcription errors through its 100% use of computerized physician order entry. Clinical pathways and standard order sets have reduced practice variation, providing a safer environment. CHALLENGES: Many projects focused on timeliness, such as emergency department wait time, lab turnaround time, and pneumonia time to initial antibiotic. Results have been mixed, with projects most successful when a link was established with patient outcomes, such as in reducing time to percutaneous transluminal coronary angioplasty for patients with acute myocardial infarction.

Adverse Drug Reaction Reporting Systems↗
PubMed2005

The discriminative stimulus, subjective, cardiovascular, and reinforcing effects of nicotine as a function of light physical activity.

Smokers often experience the acute effects of cigarette smoking while they are engaged in the light physical activity of routine tasks. However, virtually all laboratory-based research on these effects is conducted under conditions of quiet rest and, thus, may not generalize to effects in the natural environment. We examined changes in the discriminative stimulus, subjective, cardiovascular, and reinforcing effects of nicotine in humans as a function of the level of concurrent physical activity. Men and women smokers (N = 17) were initially trained to discriminate 20 microg/kg nicotine by nasal spray from placebo (0 microg/kg) at rest. Three sessions then followed, in which the generalization of discrimination was tested across a range of doses (0-20 microg/kg) while at rest or engaged in very light or light physical activity (15% and 30% of heart rate reserve, respectively) via bicycle ergometer. Generalization testing involved both two- and three-choice ("novel" option) quantitative procedures. Self-reported mood via the Profile of Mood States and visual analog scales, and cardiovascular measures of heart rate and blood pressure were obtained concurrent with discrimination responding. Nicotine reinforcement was assessed after the end of generalization testing using a choice procedure under the same rest or activity conditions. Results showed that physical activity did not significantly alter nicotine discrimination or reinforcement, as no interactions between activity and nicotine were observed. When activity and nicotine influenced the same subjective and cardiovascular responses, they acted in a generally additive fashion. These findings suggest that research on the acute effects of nicotine conducted under typical resting laboratory conditions generally are not altered by light physical activity and so may generalize to the effects of nicotine under conditions common in the natural environment.

Administration, Intranasal↗
PubMed2004

Three-dimensional computer visualization of forensic pathology data.

Despite a decade of use in US courtrooms, it is only recently that forensic computer animations have become an increasingly important form of communication in legal spheres within the United Kingdom. Aims Research at the University of Nottingham has been influential in the critical investigation of forensic computer graphics reconstruction methodologies and techniques and in raising the profile of this novel form of data visualization within the United Kingdom. The case study presented demonstrates research undertaken by Aims Research and the Department of Forensic Pathology at the University of Sheffield, which aims to apply, evaluate, and develop novel 3-dimensional computer graphics (CG) visualization and virtual reality (VR) techniques in the presentation and investigation of forensic information concerning the human body. The inclusion of such visualizations within other CG or VR environments may ultimately provide the potential for alternative exploratory directions, processes, and results within forensic pathology investigations.

Adult↗
PubMed1992

Structural and redox relationships between Paracoccus denitrificans, porcine and human electron-transferring flavoproteins.

Electron-transferring flavoprotein (ETF) was purified from the bacterium Paracoccus denitrificans and the structural and redox relationships to the porcine and human ETFs were investigated. The three proteins have essentially identical subunit masses and the alpha-helix content of the bacterial and porcine ETFs are very similar, indicating global structural similarity. An anti-(porcine ETF) polyclonal antibody that crossreacts with the human large and small subunits also crossreacts strongly with the large subunit of Paracoccus ETF. However, crossreactivity with the small subunit is very weak. Nonetheless, an amino-terminal peptide and four internal peptides of the small bacterial subunit show extensive sequence identity with the human small subunit. Local similarities in environment are also indicated by the intrinsic tryptophan fluorescence emission spectra of porcine and Paracoccus ETFs. Although the visible spectra of porcine and Paracoccus ETFs are virtually identical, flavin fluorescence in the bacterial protein is only 15% that of the mammalian protein. Further, the circular dichroic spectrum of the flavin in the bacterial protein is significantly more intense, suggesting that the microenvironment of the isoalloxazine ring is different in the two proteins. Enzymatic or photochemical reduction of Paracoccus ETF rapidly yields an anionic semiquinone; formation of the fully reduced flavin in the bacterial ETF is very slow. The spacing of the oxidation-reduction potentials of the flavin couples in the bacterial ETF is essentially identical to that in procine ETF as judged from the disproportionation equilibrium of the bacterial ETF flavin semiquinone. Together, the enzymatic reduction and disproportionation equilibria suggest that the flavin potentials of the two ETFs must be very close. The data indicate that the structural properties of the bacterial and mammalian proteins and the thermodynamic properties of the flavin prosthetic group of the proteins are very similar.

Amino Acid Sequence↗
PubMed2002

Corticosteroids: sculptors of the hippocampal formation.

The influence of corticosteroids on hippocampus-dependent learning and memory processes is now indisputable. On the other hand, closer scrutiny of early studies together with interpretations from newer studies would suggest that the proposition that corticosteroid-induced hippocampal cell death accounts fully for the associated cognitive deficits is only partially correct. Firstly, it is now clear that a specific sub-population of hippocampal neurons, the granule cells of the dentate gyrus, is more sensitive to changes in the corticosteroid environment; this fact raises the interesting question of what might be the unique properties of granule cells that render them more vulnerable to these hormones, since virtually all hippocampal cells express corticosteroid receptors. Secondly, from a critical analysis of the available data, the picture that emerges is that corticosteroids, by acting through two distinct receptors, influence not only cell birth and death, but probably also cell differentiation. Mineralocorticoid receptor (MR) occupation appears to be essential for the survival of existing and newly generated granule neurons. In contrast, while glucocorticoid receptors (GR) can induce loss of neurons in the absence of MR activation, it appears that their occupation usually results in less drastic effects involving only dendritic atrophy and loss of synaptic contacts. This revised scheme of corticosteroid actions on hippocampal structure should explain earlier observations that many of the cognition- impairing effects of corticosteroids are reversible.

Adrenal Cortex Hormones↗
PubMed2002

3-D eye movement analysis.

This paper presents a novel three-dimensional (3-D) eye movement analysis algorithm for binocular eye tracking within virtual reality (VR). The user's gaze direction, head position, and orientation are tracked in order to allow recording of the user's fixations within the environment. Although the linear signal analysis approach is itself not new, its application to eye movement analysis in three dimensions advances traditional two-dimensional approaches, since it takes into account the six degrees of freedom of head movements and is resolution independent. Results indicate that the 3-D eye movement analysis algorithm can successfully be used for analysis of visual process measures in VR. Process measures not only can corroborate performance measures, but also can lead to discoveries of the reasons for performance improvements. In particular, analysis of users' eye movements in VR can potentially lead to further insights into the underlying cognitive processes of VR subjects.

Adult↗
PubMed1984

[An approach to the evaluation of medical journals: application to original articles of La Presse Médicale and the New England Journal of Medicine published in 1982].

Medical journals play an important role in the diffusion of scientific medical information. We tried to evaluate the French medical journal, La Presse Médicale, and to compare it with the New England Journal of Medicine. We reviewed all the original articles published in 1982 (207 articles In La Presse Medicale and 152 articles in the New England Journal of Medicine): specialties, methodologies used in the studies, environment (number of authors, geographical origin, institutional origin, number and language of references, number of subjects included in the studies). The articles in both journals concerned virtually the same specialties, more than 50% of the articles dealing with the following: cancerology, cardiology, infectious diseases, endocrinology, gastroenterology. Many specialties including highly prevalent diseases were underrepresented in both journals. When treating the same kind of problems, different methodologies were used: faced with a therapeutical problem, authors in La Presse Medicale used mostly non controlled evaluations (46%, 30 articles), and few randomized controlled trials (12%, 8 articles). On the other hand, authors in the New England Journal of Medicine used mostly randomised controlled trials (56%, 36 articles), and less non controlled evaluations (26%, 16 articles). Most references were in English, even in La Presse Medicale, in which 76% of all references were not in French, and 14% of all articles had no French references. In conclusion, this study shows differences between the two journals: in particular, the methodologies used by the authors in La Presse Medicale were less pertinent than those used by the authors in the New England Journal of Medicine. This finding is important with regard to the formation of and information given to the French speaking physicians, and a strong reaction from the editors and physicians concerned is desirable.

Evaluation Studies as Topic↗
PubMed1999

Computer simulation of spacecraft/environment interaction.

This report presents some examples of a computer simulation of spacecraft interaction with space environment. We analysed a set data on electron and ion fluxes measured in 1991 1994 on geostationary satellite GORIZONT-35. The influence of spacecraft eclipse and device eclipse by solar-cell panel on spacecraft charging was investigated. A simple method was developed for an estimation of spacecraft potentials in LEO. Effects of various particle flux impact and spacecraft orientation are discussed. A computer engineering model for a calculation of space radiation is presented. This model is used as a client/server model with WWW interface, including spacecraft model description and results representation based on the virtual reality markup language.

Computer Simulation↗
PubMed1996

Cleavage of rotavirus VP4 in vivo.

The infectivity of rotavirus particles is dependent on proteolytic cleavage of the outer capsid protein, VP4, at a specific site. This cleavage event yields two fragments, identified as VP5* and VP8*. It has been hypothesized that the particle is more stable, but non-infectious, when VP4 is in the uncleaved state. Uncleaved VP4 and the resultant increased stability might be advantageous for the virus to resist environmental degradation until it infects a susceptible host. When VP4 is cleaved in the lumen of the host's gastrointestinal tract, the virus particle would become less stable but more infectious. To test this hypothesis, a series of experiments was undertaken to analyse the cleavage state of VP4 on virus shed by an infected host into the environment. Immunoblots of intestinal wash solutions derived from infant and adult BALB/c mice infected with a virulent cell culture-adapted variant of the EDIM virus (EW) or wild-type murine rotavirus EDIM-Cambridge were analysed. Virtually all of the VP4 in these samples was in the cleaved form. Moreover, cell culture titration of trypsin-treated and untreated intestinal contents from pups infected with EW indicated that excreted virus is fully activated prior to trypsin addition. It was also observed that trypsin-activated virus has no disadvantage in initiating infection in naive animals over virions containing an intact VP4. These studies indicate that VP4 is cleaved upon release from the intestinal cell and that virus shed into the environment does not have an intact VP4.

Animals↗
PubMed1997

Virtual reality: teaching tool of the twenty-first century?

Virtual reality (VR) is gaining recognition for its enormous educational potential. While not yet in the mainstream of academic medical training, many prototype and first-generation VR applications are emerging, with target audiences ranging from first- and second-year medical students to residents in advanced clinical training. Visualization tools that take advantage of VR technologies are being designed to provide engaging and intuitive environments for learning visually and spatially complex topics such as human anatomy, biochemistry, and molecular biology. These applications present dynamic, three-dimensional views of structures and their spatial relationships, enabling users to move beyond "real-world" experiences by interacting with or altering virtual objects in ways that would otherwise be difficult or impossible. VR-based procedural and surgical simulations, often compared with flight simulators in aviation, hold significant promise for revolutionizing medical training. Already a wide range of simulations, representing diverse content areas and utilizing a variety of implementation strategies, are either under development or in their early implementation stages. These new systems promise to make broad-based training experiences available for students at all levels, without the risks and ethical concerns typically associated with using animal and human subjects. Medical students could acquire proficiency and gain confidence in the ability to perform a wide variety of techniques long before they need to use them clinically. Surgical residents could rehearse and refine operative procedures, using an unlimited pool of virtual patients manifesting a wide range of anatomic variations, traumatic wounds, and disease states. Those simulated encounters, in combination with existing opportunities to work with real patients, could increase the depth and breadth of learners' exposure to medical problems, ensure uniformity of training experiences, and enhance the acquisition of clinical skills.

Anatomy↗
PubMed2000

Form representation in monkey inferotemporal cortex is virtually unaltered by free viewing.

How are objects represented in the brain during natural behavior? Visual object recognition in primates is thought to depend on the inferotemporal cortex (IT). In most neurophysiological studies of IT, monkeys hold their direction of gaze fixed while isolated visual stimuli are presented (controlled viewing). However, during natural behavior, primates visually explore cluttered environments by changing gaze direction several times each second (free viewing). We examined the effect of free viewing on IT neuronal responses in monkeys engaged in a form-recognition task. By making small, real-time stimulus adjustments, we produced nearly identically retinal stimulation during controlled and free viewing. Nearly 90% of neuronal responses were unaffected by free viewing, and average stimulus selectivity was unchanged. Thus, neuronal representations that likely underlie form recognition are virtually unaltered by free viewing.

Animals↗
PubMed2000

Computers and virtual reality for surgical education in the 21st century.

Surgeons must learn to perform operations. The current system of surgical resident education is facing many challenges in terms of time efficiency, costs, and patient safety. In addition, as new types of operations are developed rapidly, practicing surgeons may find a need for more efficient methods of surgical skill education. An in-depth examination of the current learning environment and the literature of motor skills learning provides insights into ways in which surgical skills education can be improved. Computers will certainly be a part of this process. Computer-based training in technical skills has the potential to solve many of the educational, economic, ethical, and patient safety issues related to learning to perform operations. Although full virtual-reality systems are still in development, there has been early progress that should encourage surgeons to incorporate computer simulation into the surgical curriculum.

Clinical Competence↗
PubMed2005

Influence of virtual reality training on the roadside crossing judgments of child pedestrians.

The roadside crossing judgments of children aged 7, 9, and 11 years were assessed relative to controls before and after training with a computer-simulated traffic environment. Trained children crossed more quickly, and their estimated crossing times became better aligned with actual crossing times. They crossed more promptly, missed fewer safe opportunities to cross, accepted smaller traffic gaps without increasing the number of risky crossings, and showed better conceptual understanding of the factors to be considered when making crossing judgments. All age groups improved to the same extent, and there was no deterioration when children were retested 8 months later. The results are discussed in relation to theoretical arguments concerning the extent to which children's pedestrian judgments are amenable to training.

Accidents, Traffic↗
PubMed1997

Characterization of non-peptide antagonist and peptide agonist binding sites of the NK1 receptor with fluorescent ligands.

Ligand recognition of the NK1 receptor (substance P receptor) by peptide agonist and non-peptide antagonist has been investigated and compared by the use of fluorescent ligands and spectrofluorometric methods. Analogues of substance P (SP) labeled with the environment-sensitive fluorescent group 5-dimethylaminonaphthalene-1-sulfonyl (dansyl) at either position 3, 8, or 11 or with fluorescein at the Nalpha position were synthesized and characterized. Peptides modified at the alpha-amino group or at positions 3 or 11 conserved a relatively good affinity for NK1 and agonistic properties. Modification at position 8 resulted in an 18, 000-fold decrease in affinity. A fluorescent dansyl analogue of the non-peptide antagonist CP96,345 was prepared and characterized. The quantum yield of fluorescence for dansyl-CP96,345 was much higher than for any of the dansyl-labeled peptides indicating that the micro-environment of the binding site is more hydrophobic for the non-peptide antagonist than for the peptide agonists. Comparison of collisional quenching of fluorescence by the water-soluble hydroxy-Tempo compound showed that dansyl-CP96,345 is buried and virtually inaccessible to aqueous quenchers, whereas dansyl- or fluoresceinyl-labeled peptides were exposed to the solvent. Anisotropy of all fluorescent ligands increased upon binding to NK1 indicating a restricted motional freedom. However, this increase in anisotropy was more pronounced for the dansyl attached to the non-peptide antagonist CP96,345 than for the fluorescent probes attached to different positions of SP. In conclusion, our data indicate that the environment surrounding non-peptide antagonist and peptide agonists are vastly different when bound to the NK1 receptor. These results support recent observations by mutagenesis and cross-linking work suggesting that peptide agonists have their major interaction points in the N-terminal extension and the loops forming the extracellular face of the NK1 receptor. Our data also suggest that neither the C terminus nor the N terminus of SP appears to penetrate deeply below the extracellular surface in the transmembrane domain of the receptor.

Animals↗
PubMed1984

Swimming immobility of REM sleep deprived rats reared in different environments.

This study tested the hypothesis that environmental rearing treatments which alter the REM sleep levels of rats affect swimming immobility, an adaptive, REM sleep sensitive behavior. At weaning, 72 female Sprague-Dawley rats were maintained in either an enriched, an impoverished, or a social control environment for 32-33 days. They were then placed in either a REM sleep depriving platform-in-water condition or in one of two control conditions (large platform or dry control) for 4 days before being scored for swimming immobility during a 10-min swimming test. A 3 (environments) X 3 (platforms) ANOVA revealed a main effect for environments, F(2,63) = 5.20, p less than 0.01. Enriched rats exhibited a behavioral advantage over impoverished rats under the large platform control condition, F(1,63) = 6.58, p less than 0.025, and under the dry control condition, F(1,63) = 6.14, p less than 0.025. However, under the REM depriving condition, their behavioral advantage was virtually eliminated, F(1,63), p less than 1. The conclusion that the REM sleep levels of the rat groups probably determined their swimming immobility scores is discussed.

Adaptation, Physiological↗
PubMed1994

Congestion, air pollution, and road fatalities in urban areas.

The continuous rapid growth in vehicle miles travelled coupled with the rapid increase in traffic congestion on highways of virtually every large urban area, explain a major portion of the observed deterioration of urban air quality. To halt this deterioration and to secure safe and healthy environments and improve the quality of life in our cities, it is useful to initiate and implement programs that treat jointly traffic congestion, air quality, and road safety. Market-based strategies, driven by price mechanisms, have been proposed as the best and most efficient way to decrease traffic congestion and to reduce vehicle emission. Congestion pricing, emission fees, reducing emissions of high-polluting vehicles, and introducing more efficient vehicle and/or fuel technologies are not mutually exclusive strategies and therefore they can be employed jointly within an overall strategy. In view of the conflicting objectives that may exist between improving urban air quality and reducing road fatalities and traffic congestion, it is of great importance to investigate thoroughly these functional relationships. The results of such studies will help decision makers identify the "socially optimal level of congestion" that will yield the highest net social benefit.

Accidents, Traffic↗