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Results for “Reality Testing”

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At least 1,675 records · Page 93Linked to original sources
PubMed1997

Synergism between tobramycin and ceftazidime against a resistant Pseudomonas aeruginosa strain, tested in an in vitro pharmacokinetic model.

Synergism between two antibiotics is usually tested by a checkerboard titration technique, or by time-kill methods. Both methods have the disadvantage that synergism is determined at constant concentrations of the antibiotics, which do not reflect reality in vivo. In the present study we determined whether synergism between tobramycin and ceftazidime can be found at declining concentrations below the MIC, and whether change in dosing sequence of the antibiotics would result in differences in killing. Three monotherapy and six combination therapy schedules were tested in an in vitro pharmacokinetic model, using a Pseudomonas aeruginosa resistant to both antibiotics. During all q8h dosing schedules the peak concentration (Cmax) was adjusted to the MIC for the strain of both antibiotics. During all monotherapy regimens bacterial growth was present, while all six combination therapy schedules showed significant killing. At t = 24 h there were no differences between all combination therapy schedules, but at t = 8 h the two combination therapy schedules with administration of tobramycin once daily showed a significantly faster killing. By using the area under the killing curve (AUKC) as a parameter for synergistic killing, simultaneous combination therapy starting with tobramycin once daily was significantly better than all other regimens. We conclude that there is synergism between tobramycin and ceftazidime at declining antibiotic concentrations below the MIC, resulting in a pronounced killing of a resistant Pseudomonas strain. Infections due to resistant Pseudomonas strains could possibly be treated by a synergistic combination of these drugs.

Anti-Bacterial Agents↗
PubMed1990

Progress in the enzyme diagnosis of liver disease: reality or illusion?

This paper discusses the progress of enzyme diagnosis by different examples. These include: the requirement for improved enzymological screening, despite the introduction of a test for hepatitis C; the imbalance between the popularity of "unexplained chronic aminotransferase elevations" and efforts to solve the inherent problems; the inadequate attempts to use the metabolic changes in the hepatocytes to improve diagnosis, prognosis, and pathophysiological understanding of viral liver diseases; the remarkable investigations into the 2'-5'-oligoadenylate synthetase for better control of interferon therapy in chronic viral hepatitis; the use of enzymes as markers of etiology, particularly for the detection of alcohol induced liver diseases; the continuing preference for the aminotransferases in this scenario although the ratios of aspartate aminotransferase over alanine aminotransferase, or of mitochondrial aspartate aminotransferase over total aspartate aminotransferase activity, largely depend on the severity and intralobular localization of damage and the stage of the liver disease.

Clinical Enzyme Tests↗
PubMed2001

Pilot test of an Internet virtual world chat room for rural teen smokers.

OVERVIEW: This pilot study evaluated the acceptability and efficacy of an Internet-based virtual reality "world" for teen smoking cessation. Rural teens at six school sites interacted in real-time in the virtual world with a trained cessation counselor and other teen smokers over a 2-month period in seven 1-hour chat sessions. The cessation counselor used motivational interviewing, a "client-centered" nonconfrontational approach to behavior change that has shown promise with behaviors resistant to change. Smoking behavior and attitudes were assessed at baseline, after intervention, and at 1-month follow-up. Significant changes were found in quitting, amount smoked, and intentions to quit. Positive trends were seen in past-week abstinence rates, quit attempts, and attitudes toward quitting.

Adolescent↗
PubMedDate not supplied

Assumptions and realities of the NCLEX-RN.

Every three years the National Council of State Boards of Nursing conducts a practice analysis to verify the activities that are tested on the licensure exam (NCLEX-RN). Faculty can benefit from information in the practice analysis to ensure that courses and experiences adequately prepare graduates for the NCLEX-RN. This summary of the practice analysis challenges common assumptions and provides recommendations for faculty.

Accreditation↗
PubMed2006

New strategies for blood donor screening for hepatitis B virus: nucleic acid testing versus immunoassay methods.

Serologic testing for hepatitis B virus (HBV) surface antigen (HBsAg) and antibody to HBV core antigen (anti-HBc) has historically been the foundation of blood screening, while HBV nucleic acid testing (NAT) was recently developed to detect HBsAg-negative, anti-HBc-negative blood units donated during early acute infection. Comparison data on seroconversion panels using HBsAg assays of varying sensitivities and pooled- or single-sample NAT, along with viral load estimates corresponding to HBsAg assay detection limits, have provided information on the theoretical benefits of NAT relative to HBsAg. Model-derived estimates have generally been predictive of the yields of DNA-positive, HBsAg-negative window period blood units detected in a number of studies from Europe, Japan, and the US. Studies indicate that the added benefit of pooled-sample NAT is relatively small in areas of low endemicity, with greater yields in areas highly endemic for HBV. Single-sample NAT would offer more significant early window period closure and could prevent a moderate number of residual HBV transmissions not detected by HBsAg assays; however, no fully automated single-sample HBV NAT systems are currently available.Even single-sample HBV NAT may not substitute for anti-HBc screening, as indicated by studies of donors with isolated anti-HBc who have extremely low DNA levels undetectable by standard single-sample NAT and who have been associated with transfusion-transmitted HBV. Moreover, HBsAg testing may still be needed even in the setting of combined anti-HBc and NAT screening. HBsAg-positive units from donors in the chronic stage of infection may contain very low or intermittently detectable DNA levels that single-sample NAT would miss. Although such donors are usually anti-HBc reactive and would be interdicted by anti-HBc screening, some lack anti-HBc. Extensive parallel testing will be needed to determine whether single-sample NAT in combination with anti-HBc might be sufficient to detect all the infectious donors currently interdicted by HBsAg testing. In countries that do not screen for anti-HBc, HBsAg testing would be the only means of detecting donations from chronically infected individuals with low/intermittently detectable DNA, since even single-donor NAT would not identify these potentially infectious blood units. In the future, the current fully automated HBsAg assays may incorporate significant sensitivity improvements, and automated single-sample HBV NAT may become a reality. Each country will need to develop its blood screening strategy based on HBV endemicity, yields of infectious units detected by different serologic/NAT screening methods, and cost effectiveness of test methods in ensuring blood safety.

Blood Donors↗
PubMed1997

Molecular basis of HNPCC: mutations of MMR genes.

Hereditary nonpolyposis colorectal cancer (HNPCC) is inherited as a dominant disorder caused by germline defects in one of at least four mismatch repair (MMR) genes. Two of these genes, hMSH2 and hMLH1, account for the vast majority of the germline mutations in HNPCC kindreds, whereas hPMS1 and hPMS2 are mutated in only few families. MMR genes also are susceptible to somatic mutations in sporadic tumors. The mutational spectrum of the MMR genes shows no predominant type of mutation. Furthermore, the mutations are spread throughout the length of the genes, with no significant hot spots. Identification of MMR genes as the cause of HNPCC made presymptomatic diagnosis a reality. However, the presence of multiple genes and the heterogeneity of mutations present challenges to the development of diagnostic tests for this disease.

Adaptor Proteins, Signal Transducing↗
PubMed1994

An evaluation of implicit and explicit solvent model systems for the molecular dynamics simulation of bacteriophage T4 lysozyme.

In this report we examine several solvent models for use in molecular dynamics simulations of protein molecules with the Discover program from Biosym Technologies. Our goal was to find a solvent system which strikes a reasonable balance among theoretical rigor, computational efficiency, and experimental reality. We chose phage T4 lysozyme as our model protein and analyzed 14 simulations using different solvent models. We tested both implicit and explicit solvent models using either a linear distance-dependent dielectric or a constant dielectric. Use of a linear distance-dependent dielectric with implicit solvent significantly diminished atomic fluctuations in the protein and kept the protein close to the starting crystal structure. In systems using a constant dielectric and explicit solvent, atomic fluctuations were much greater and the protein was able to sample a larger portion of conformational space. A series of nonbonded cutoff distances (9.0, 11.5, 15.0, 20.0 A) using both abrupt and smooth truncation of the nonbonded cutoff distances were tested. The method of dual cutoffs was also tested. We found that a minimum nonbonded cutoff distance of 15.0 A was needed in order to properly couple solvent and solute. Distances shorter than 15.0 A resulted in a significant temperature gradient between the solvent and solute. In all trajectories using the proprietary Discover switching function, we found significant denaturation in the protein backbone; we were able to run successful trajectories only in those simulations that used no switching function. We were able to significantly reduce the computational burden by using dual cutoffs and still calculate a quality trajectory. In this method, we found that an outer cutoff distance of 15.0 A and an inner cutoff distance of 11.5 worked well. While a 10 A shell of explicit water yielded the best results, a 6 A shell of water yielded satisfactory results with nearly a 40% reduction in computational cost.

Bacteriophage T4↗
PubMed2003

A virtual reality system for the assessment and rehabilitation of the activities of daily living.

Successful rehabilitation with respect to the activities of daily living (ADL) requires accurate and effective assessment and training. A number of studies have emphasized the requirement for rehabilitation methods that are both relevant to the patient's real world environment, and that can also be transferred to other daily living tasks. Virtual reality (VR) has many advantages over other ADL rehabilitation techniques, and offers the potential to develop a human performance testing and training environment. Therefore, in this study, the virtual supermarket was developed and the possibility of using a VR system to assess and train cognitive ability in ADL investigated. This study demonstrates that VR technology offers great promise in the field of ADL training.

Activities of Daily Living↗
PubMed1984

Written simulation of patient-doctor encounters. 1. Research instrument for registration of the performance of general practitioners.

A written simulation of patient-doctor encounters is described, involving five patients with vague complaints, an 'instruction' patient with sinusitis and a 'test' patient with acute appendicitis. Nineteen general practitioners were confronted with it. The extent to which the simulation distorted reality and the implications of such distortions were considered in an attempt to assess the content validity. The conclusion was that the simulation gave a realistic impression of the general practitioners' diagnostic and therapeutic approach to patients with vague complaints. The searching procedures in relation to the complaint and the patient's perception of the complaint were adequately depicted, and the therapeutic procedures approximated closely to reality. There was some distortion in the attention paid to psychosocial aspects as these were given more attention in the simulation than they receive in reality.

Acute Disease↗
PubMed2000

A chi-square goodness-of-fit analysis of dependent resource selection data.

The chi2 goodness-of-fit test is commonly used for testing if animals use resources in proportion to availability. This method assumes independence of resource selection among animals. In reality, this assumption is violated if animals display antisocial or gregarious behavior. Data from a study of sharp-tailed grouse in eastern Washington suggested some dependency among observations. Realizing that this dependency can have a great influence on inference for resource selection data, we develop a technique to incorporate information on dependent observations through a simple adjustment of the usual goodness-of-fit statistic. We also demonstrate how confidence intervals on proportional use may be modified for dependent observations. Simulation is used to compare our method to other methods.

Animals↗
PubMed2006

Impaired allocentric spatial memory underlying topographical disorientation.

The cognitive processes supporting spatial navigation are considered in the context of a patient (CF) with possible very early Alzheimer's disease who presents with topographical disorientation. Her verbal memory and her recognition memory for unknown buildings, landmarks and outdoor scenes was intact, although she showed an impairment in face processing. By contrast, her navigational ability, quantitatively assessed within a small virtual reality (VR) town, was significantly impaired. Interestingly, she showed a selective impairment in a VR object-location memory test whenever her viewpoint was shifted between presentation and test, but not when tested from the same viewpoint. We suggest that a specific impairment in locating objects relative to the environment rather than relative to the perceived viewpoint (i.e. allocentric rather than egocentric spatial memory) underlies her topographical disorientation. We discuss the likely neural bases of this deficit in the light of related studies in humans and animals, focusing on the hippocampus and related areas. The specificity of our test indicates a new way of assessing topographical disorientation, with possible application to the assessment of progressive dementias such as Alzheimer's disease.

Activities of Daily Living↗
PubMedDate not supplied

[Non-invasive electrical markers in patients with the Brugada syndrome].

Throughout the 13 years of recognizing the Brugada syndrome as a separate entity, there has been a search for invasive and non-invasive markers for detecting risk of life-threatening arrhythmic events, particularly for asymptomatic individuals in whom the first manifestation may be sudden cardiac death. Hence, the preclinical diagnosis is pivotal for adequate and timely preventive measures. The objective of this study was to compare various non-invasive markers to characterize and stratify patients at risk. Late potentials, QT interval, QT dispersion, and heart variability were analyzed over a two-year period, in 20 patients (17 men and 3 women) with the Brugada syndrome (symptomatic and asymptomatic) and compared with 20 normal individuals similar in age and gender (control group). Late potentials were present in 80% of patients versus 5% in the control group (p < 0.0001); all of these with recurrent episodes had late potentials. In conclusion, this is the most important non-invasive marker for risk stratification, recurrences and inducibility of malignant arrhythmias during electrophysiological testing. Markers, invasive and non-invasive, should be considered integrally, for a better diagnostic and prognostic approach to reality.

Adult↗
PubMed2006

Sperm function tests and fertility.

Traditionally, the diagnosis of male infertility has depended upon a descriptive evaluation of human semen with emphasis on the number of spermatozoa that are present in the ejaculate, their motility and their morphology. The fundamental tenet underlying this approach is that male fertility can be defined by reference to a threshold concentration of motile, morphologically normal spermatozoa that must be exceeded in order to achieve conception. Many independent studies have demonstrated that this fundamental concept is flawed and, in reality, it is not so much the absolute number of spermatozoa that determines fertility, but their functional competence. In the light of this conclusion, a range of in vitro tests have been developed to monitor various aspects of sperm function including their potential for movement, cervical mucus penetration, capacitation, zona recognition, the acrosome reaction and sperm-oocyte fusion. Such functional assays have been found to predict the fertilizing capacity of human spermatozoa in vitro and in vivo with some accuracy. Recent developments in this field include the introduction of tests to assess the degree to which human spermatozoa have suffered oxidative stress as well as the integrity of their nuclear and mitochondrial DNA. Such assessments not only yield information on the fertilizing capacity of human spermatozoa but also their ability to support normal embryonic development.

Acrosome Reaction↗
PubMed2002

Differential diagnosis of dementia: clinical examination and laboratory assessment.

Recent breakthroughs in putative disease-modifying interventions for Alzheimer's disease (AD) underscore the urgency of making the earliest possible diagnosis. In the absence of a convenient and reliable laboratory test for AD, the clinical assessment is still the cornerstone of the diagnostic approach. This article provides a basis for conducting an assessment within the realities of a busy clinical practice for patients complaining of cognitive decline. The assessment will enable the clinician to diagnose the earliest manifestation of AD.

Affect↗