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PubMedDate not supplied

Multi-center trial with protocols and prototype test objects for the assessment of MRI equipment. EEC Concerted Research Project.

A trial was carried out in which the protocols and prototype test objects developed under a European Economic Community concerted research project for the assessment of MR imaging equipment were tested in a series of commercial imaging systems situated throughout Europe. In general, many imperfections were discovered in the imaging performance of the scanners and, in particular, the accuracy and precision with which the relaxation times T1 and T2 could be measured from the images were found to be rather disappointing.

European Union↗
PubMedDate not supplied

Digital tomosynthesis: phantom and patient studies with a prototype unit.

A prototype digital linear tomographic system has been developed and used in patient and phantom studies. Phantom work demonstrated 0.6 line pairs/mm of spatial resolution, a slice thickness of 5 mm to 6 mm, range of reconstruction of 1 cm to 20 cm above tabletop, reconstruction time of 2 to 45 seconds per slice depending on matrix size, and a 280 mm field of view at the tabletop. Patient studies were conducted in three categories: renal imaging in 8 patients during intravenous urography (IVU); central airways imaging in 4 patients undergoing laser resection of endobronchial tumor; the knee of one volunteer. The digital tomograms from IVU studies were similar to the conventional film tomograms, and the only parenchymal abnormality, a renal cyst, was identified by both modalities. Digital tomograms of the mediastinum were superior to the chest radiographs in determining the patency of the central airways. With further development, digital tomosynthesis could offer greater spatial resolution, faster reconstructions, and less radiation than computed tomography (CT) or conventional tomography.

Humans↗
PubMed1994

Integrating consultation and semi-automatic knowledge acquisition in a prototype-based architecture: experiences with dysmorphic syndromes.

The paper describes an application of cognitive theories of Tversky and Rosch to prototype similarity of dysmorphic syndromes cases. The knowledge-based system supports diagnostic consultation and research in dysmorphic syndromes. It has been used routinely for many years. The knowledge base is semi-automatically generated from known cases of an outpatient clinic. Some results of the evaluation process of the system's achievements are shown. General conclusions based on the experience with this successful system are discussed.

Artificial Intelligence↗
PubMed1992

Clinical evaluation of a prototype glucose electrode.

A new prototype direct reading glucose electrode working with glucose oxidase and hydrogen peroxide was preliminarily tested clinically during insulin-induced hypoglycemia in eight healthy subjects, and during hyperglycemia in five dysregulated diabetic patients. The results for 282 whole blood samples were compared to those of our routine method, which measures the glucose concentration in whole blood. The correlation was: y = 1.05.x - 0.05 mmol/L, r = 0.99. The glucose electrode measured a glucose concentration of 10.5 mmol/L +- 0.49 mmol/L (between-day imprecision) in a control serum (glucose 10.0 mmol/L). The glucose electrode supposedly responds to the activity of glucose that equals the molality (mmol glucose per kg water). The ratio of results with the glucose electrode and our routine method was lower than the expected ratio between water concentration in calibrator and whole blood, which is 1.18. A steep gradient from blood sample to glucose electrode, depending on the diffusion coefficient and hematocrit might explain the discrepancy.

Adult↗
PubMed1996

Testing prototype products in the operating room.

Historically, the discussion of which products to use in a hospital has centered around disposable versus reusable products; however, new technology has produced a line of products that are not only disposable but degradable. Perioperative staff members at Redmond Regional Medical Center, Rome, Ga, participated in the testing, evaluation, and use of these prototype products during their development.

Disposable Equipment↗
PubMed1995

Usefulness of a prototype intravascular ultrasound imaging in evaluation of aortic dissection and comparison with angiographic study, transesophageal echocardiography, computed tomography, and magnetic resonance imaging.

The aim of this study was to evaluate the accuracy of information obtained with a prototype intravascular ultrasound (IVUS) system in chronic aortic dissection by comparing results with angiography, transesophageal echocardiography (TEE), computed tomography, or magnetic resonance imaging. We assigned 15 patients to IVUS imaging after they underwent angiography. The detection rate of the intimal flap was 100% in all segments of the aorta, and the detection rate of the intimal tear was 0%, 50%, 50%, and 77.8% in the ascending, arch, descending, and abdominal aorta, respectively. IVUS demonstrated 100% of the celiac and renal arteries, and 80% of the superior mesenteric arteries as well as their relation to dissection. It clarified the origin of 12 of 60 main abdominal branches (20%) which were not clear on the angiogram. It also determined the distal extent of the dissection in all cases. With regard to the size of the vessel, there was a good correlation between IVUS and computed tomographic values (r = 0.98, p < 0.01). No complications occurred in any patient. IVUS accurately demonstrated thrombus or spontaneous echo contrast in the false lumen that was confirmed with computed tomography or TEE, or both. It was especially useful in evaluating the abdominal aorta with regard to determining the size of the vessel, the extent of dissection, the relation of the branches to the false lumen, and the detection of intimal tears--important information for follow-up of patients and for planning surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1997

Healthcare decisions and product labeling: results of a consumer comprehension study of prototype labeling for proposed over-the-counter cholestyramine.

This study was designed to determine whether randomly selected subjects could comprehend prototype consumer-oriented package labeling and inserts for over-the-counter cholestyramine, a nonsystemic lipid-lowering agent. The primary messages communicated in the label were that consumers should see their doctor before taking cholestyramine and should read the full package insert. In addition, the label communicated indication, dosage, and preparation, as well as key warnings about use with other medications. The insert reinforced the message about seeing the doctor before taking cholestyramine and before taking concurrent medications, further explained the purpose of the drug and its correct use, and provided information about the two types of cholesterol, risk factors for heart disease, and the importance of diet and exercise. A total of 1,806 randomly selected subjects were interviewed in their homes in 40 geographic regions. After examining the product container with one of the three labels being tested, they were given a questionnaire to test their understanding of the label communication points. They were then asked to read the package insert and tested on their understanding of the messages it communicated. Responses were analyzed by gender, age, and education level, as well as by label format. For the education-level subgroup analysis, the high-school-nongraduate group was supplemented by 419 subjects, for a total of 2,225 subjects. Statistical analyses were performed on completed questionnaires by an independent data analysis company. The net correct response to the two primary communication objectives was 99% among the total population. Responses to questions addressing the use of concurrent medications; types of cholesterol; purpose, dosage, and preparation of the medication; and diet and exercise were also clearly understood. This study showed a high level of comprehension of the purpose and correct use of cholestyramine among both high-school graduates and nongraduates.

Adolescent↗
PubMed1996

Mapping air contaminants indoors using a prototype computed tomography system.

Single and multiple plumes of sulphur hexafluoride were measured and mapped using a prototype open-path Fourier transform infrared spectrometer (OP-FTIR)-computed tomography (CT) system in an indoor exposure chamber. The OP-FTIR-CT system accurately mapped the position of concentration peaks at different locations in the chamber, and estimated concentrations within a range of 4-50% when compared with point samples measured by gas chromatography with an electron capture detector. Two OP-FTIR spectrometer ray configurations, one with 100 rays and the other with 136 rays, were used to scan the chamber and reconstruct the concentration maps. Ray configuration and time to scan the entire chamber were found to have a profound effect on the quality of the reconstructed maps. The ability to obtain real-time, non-invasive measurements, and to generate spatially and temporally resolved maps of multiple chemicals, makes the OP-FTIR-CT system a promising technique for monitoring source emissions and evaluating exposures to air contaminants in a workplace.

Air Pollutants↗
PubMed1978

Evaluation of a Behring laser-nephelometer prototype in the measurement of IgG, IgA and IgM.

A helium-neon laser nephelometer prototype manufactured by Hoechst Behring Institut was evaluated and used in our laboratory during a two-month period for the measurement of IgG, IgA and IgM. Two methods of dilution were usedto prepare standard curves. The best results were obtained when the patient serum was diluted one hundred fold (10-100 microliter) and incubated for 15 min at room temperature in a disposable plastic cuvette with the specific antiserum diluted five fold (100-300 microliter). The intensity of the light scattered by the antigen-antibody complexes was then immediately read on the digital voltmeter. The working ranges were 186-5944 mg/dl for IgG, 33-1066 mg/dl for IgA and 17-545 mg/dl for IgM. Standard curves obtained for the three immunoglobulins on six different days could be superimposed perfectly demonstrating an excellen reproducibility. The coefficient of variation for IgG (n = 8) was 4.1% at 5800 mg/dl. The results (n = 37) produced by the laser nephelometer (y) correlated very well with those obtained by radial immunodiffusion (x) for: IgG y = 8.07 + 1.00 X, r = 0.997, IgA y = - 6.51 + 1.05 X, r = 0.996, IgM y = 3.35 + 0.98 X, r = 0.998.

Evaluation Studies as Topic↗
PubMed1989

Description and appraisal of a prototype digital fluorographic system.

A prototype system for digital fluorography (DF) has been developed from commercially available DSA equipment coupled to a standard screening unit. We present our initial clinical experience of this system with particular reference to the ergonomics, the image quality and the effect of image processing. We have concentrated upon dynamic studies such as upper gastrointestinal tract barium studies where the logistic advantages of the system are considerable. We have found DF to be ergonomically more efficient than conventional techniques. Using careful image processing the 512*512 matrix images were considered diagnostic for most studies assessed.

Humans↗
PubMed2000

Effects of the prototypical mGlu(5) receptor antagonist 2-methyl-6-(phenylethynyl)-pyridine on rotarod, locomotor activity and rotational responses in unilateral 6-OHDA-lesioned rats.

In the present study, we evaluated the effect of the prototypical metabotropic glutamate receptor 5 (mGlu(5)) antagonist 2-methyl-6-(phenylethynyl)-pyridine (MPEP) on motor behaviour in rats using the accelerating rotarod, spontaneous locomotor activity and the 6-hydroxy-dopamine (6-OHDA) lesion model to assess its treatment potential for Parkinson's disease. The data indicate that MPEP at doses between 7.5 and 300 mg/kg, p.o. did not disrupt endurance performance on the accelerating rotarod (4-40 rpm in 300 s) which indicates that MPEP has a relatively high safety margin. However, while ineffective at doses of 3.75, 7.5 and 15 mg/kg (p.o.) MPEP inhibited spontaneous locomotor activity at doses of 30 and 100 mg/kg (p.o.). In the 6-OHDA rat rotation model, at doses of 7.5, 15 and 30 mg/kg (p.o.), MPEP induced a dose-dependent ipsilateral rotational response that reached statistical significance at the highest dose tested. This effect was relatively small but consistent. In combination with direct or indirect dopamine agonists, i.e. apomorphine (0.25 mg/kg, s.c.) and D-amphetamine (2.5 mg/kg, i.p.), MPEP (7.5, 15 or 30 mg/kg, p.o.) was found to significantly inhibit these dopamine receptor mediated rotational responses. MPEP injected at a dose of 30 mg/kg also inhibited the rotational response induced by L-DOPA (25 mg/kg, i.p.). (+)MK-801 was used in these rotation experiments as the reference compound. In view of these findings, it could be concluded that MPEP and potentially other mGlu(5) receptor antagonists are probably not appropriate drug candidates for the symptomatic treatment of Parkinson's disease.

Animals↗
PubMed1999

Interleukin 2-Bax: a novel prototype of human chimeric proteins for targeted therapy.

During the past few years many chimeric proteins have been developed to target and kill cells expressing specific surface molecules. Generally, these molecules carry a bacterial or plant toxin that destroys the unwanted cells. The major obstacle in the clinical application of such chimeras is their immunogenicity and non-specific toxicity. We have developed a new generation of chimeric proteins, taking advantage of apoptosis-inducing proteins, such as the human Bax protein, as novel killing components. The first prototype chimeric protein, IL2-Bax, directed toward IL2R-expressing cells, was constructed, expressed in Escherichia coli and partially purified. IL2-Bax increased the population of apoptotic cells in a variety of target T cell lines, as well as in human fresh PHA-activated lymphocytes, in a dose-dependent manner and had no effect on cells lacking IL2R expression. The IL2-Bax chimera represents an innovative approach for constructing chimeric proteins comprising a molecule that binds a specific cell type and an apoptosis-inducing protein. Such new chimeric proteins could be used for targeted treatment of human diseases.

Apoptosis↗
PubMedDate not supplied

Preliminary evaluation of the prototype stereoscopic endoscope: precise three-dimensional measurement system.

A prototype stereoscopic endoscope (incorporating two charged-coupled devices), developed for the accurate three-dimensional measurement of gastrointestinal tract lesions, was initially evaluated with two-dimensional target grids and in vitro measurement of 15 objects of known size (marbles, cubes, and rectangular prisms) placed in a plastic model of the sigmoid colon. Images of the objects were captured and stored in a computer. Stereoscopic measurements were compared with results from the standard (open biopsy forceps) method by a blinded endoscopist. The volume measured with the stereoscope did not differ significantly from the true volume, whereas the volume obtained with the open biopsy forceps method differed significantly from the actual volume, consistently underestimating the actual size. The aberration ratios (percentage deviation between the measured and true volume, expressed as mean +/- SD) obtained with the stereoscopic endoscope were superior (9.2% +/- 9.5%) to those obtained with the open biopsy forceps method (-34.0% +/- 26.8%). These preliminary in vitro results with the stereoscope show considerable promise for the simple and precise three-dimensional measurement of gastrointestinal lesions and warrant human clinical trials.

Endoscopes, Gastrointestinal↗
PubMed2003

Safety with access scaffolds: development of a prototype decision aid based on accident analysis.

PROBLEM: Accidents involving temporary access systems, particularly temporary scaffolds, account for a large proportion of injuries in the construction industry worldwide. METHOD: This paper outlines the development of a prototype decision aid (SCAFPASS, an abbreviation for Scaffold Planning Aid for System Safety) to promote access scaffold safety. It was guided by an examination of the root-causes and management deficiencies apparent in: (a) paper-based files of 186 access-related incidents held by the Health and Safety Executive (HSE) in the UK; and (b) computer-based files of 2,910 incidents appearing in the HSE database between 1997 to 2000. RESULTS: The more frequent root-causes included the fitting of defective components, unauthorized modification of the structure, omission of barriers, and errors resulting in simple, readily detectable structural faults. Common managerial deficiencies included failure to control risk, unsafe methods and procedures, and inadequate training and supervision. IMPACT ON INDUSTRY: SCAFPASS aims to avoid these root-causes by improving safety management from the outset and throughout all phases of a project.

Accidents, Occupational↗
PubMed1996

Development of an intraluminal device for the treatment of aortic regurgitation: prototype and in vitro testing system.

OBJECTIVES: Development of an intraluminal device to reduce aortic regurgitation could provide a strategy intermediate between medical treatment and aortic valve replacement. An initial prototype and a testing system have been designed. METHODS: Aortic valves obtained from heart transplant recipients were explanted and assessed in a mock circulatory loop with resistive and capacitive elements, including pressure-flow characteristics, similar to those of a normal arterial system. Normal heart function was simulated by a pulsatile ventricular-assist device. Pressure on each side of the valve and flow through the valve were recorded, allowing the calculation of regurgitant fractions and transvalvular gradients. Six solid geometrically differing obturators were tested. RESULTS: All six designs resulted in significant reduction in aortic regurgitation (p < 0.0001), ranging from 15% to 38% improvement compared with control values. Small increases in transvalvular gradients (from 0 to 7 mm Hg) were also noted. DISCUSSION: Initial results suggest that an intraluminally placed obturator can reduce aortic regurgitation without creating clinically significant transvalvular gradients. These initial in vitro experiments demonstrate the feasibility of an intraluminal device for the treatment of aortic valve disease, and further investigation is warranted.

Aortic Valve↗
PubMed2001

Are Alzheimer's disease patients able to learn visual prototypes?

Recently, controversial results emerged regarding visual prototype learning in Alzheimer's disease (AD). The aim of this study was to elucidate this issue in a larger population of AD patients. The AD patients (N=72) and age-matched healthy control subjects (N=25) learned to recognize and to categorize visual dot patterns. In comparison with the control subjects, the AD patients as a group showed dysfunctions in the recognition task, whereas categorization was relatively spared in their case. Recognition was impaired in patients with mild AD (Mini-Mental score: 18-23) and moderate AD (Mini-Mental score<18), whereas categorization was impaired only in patients with moderate AD. These results suggest that while the medio-temporal/diencephalic explicit memory system is markedly affected even in early AD, the sensory neocortical areas mediating implicit category learning display a sufficient degree of functional capacity until later stages of the disease.

Aged↗
PubMedDate not supplied

The validity of the California Q-set Alexithymia Prototype.

The author examined the validity of the California Q-set Alexithymia Prototype (CAQ-AP), an observer- and self-report measure of the alexithymia construct. Alexithymia similarity scores (based on observer reports) were correlated with scores on several relevant self-report scales in a sample of 155 undergraduate college students. Alexithymia was positively correlated with neuroticism, depression, and anxiety; and negatively with extraversion, openness, and emotional expression. These correlations were statistically significant (P < 0.05) and in the expected direction. The CAQ-AP has passed its second validity check and, again, can be recommended as an observer measure of the alexithymia construct.

Adult↗
PubMed2003

Lethal mutagenesis of the prototypic arenavirus lymphocytic choriomeningitis virus (LCMV).

Passage of the prototypic arenavirus lymphocytic choriomenigitis virus (LCMV) in cultured cells in the presence of the mutagenic agent 5-fluorouracil (FU) resulted in efficient and systematic virus extinction under conditions that did not significantly affect cell survival. FU-mediated extinction of LCMV was associated with 3.6- to 10-fold increases in the mutation frequencies for the three viral genes examined, but with only very modest effects on virus replication and transcription during a single round of infection. Likewise, FU did not affect expression of a LCMV minigenome. In contrast, the well documented antiviral effect of ribavirin against LCMV was not associated with significant increases in virus mutation frequencies, but rather with a dramatic inhibition of both viral RNA synthesis and LCMV minigenome expression. Mutagen induced viral extinction has been recently reported for positive strand RNA viruses polio and foot-and-mouth disease, and the lentivirus HIV-1. Our findings indicate that lethal mutagenesis can be effective also against LCMV, a negative strand RNA virus. Moreover, FU treatment prevented the establishment of LCMV persistent infection in mice deficient in B and T cells, suggesting the feasibility in vivo of lethal mutagenesis as a novel antiviral strategy.

Animals↗