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At least 127 records · Page 7Linked to original sources
PubMed1990

Studies on the development of an ELISA kit for microbiological monitoring. 1. Evaluation of the reliability of the prototype kit by field tests.

The prototype of an ELISA kit using protein A as the second reaction reagent for mice and anti-rat IgG for rats was prepared for seromonitoring of the Sendai virus and mouse hepatitis virus (MHV)/sialodacryoadenitis virus (SDAV)/Parker's rat coronavirus (PCV) infections. The respective antigen strains and protein concentrations were Sendai virus MN strain, 2 micrograms/ml and MHV Nu-67 strain, 5 micrograms/ml. The reliability of this prototype kit was investigated in two field tests performed on a total of 10,094 mouse and rat sera from 147 institutions. The results indicated that the two types of kits for the two species of animals were highly specific, but it is necessary to increase the detection sensitivity of the MHV antigen for the MHV antibody of mice and SDAV/PCV antibodies of rats.

Animals↗
PubMed1990

The effect of prototype-based versus attribute-based presentation forms on the acquisition of a medical concept.

The purpose of this study was to determine the differential effect of two presentation-forms on the acquisition of the concept of shock. It is hypothesized that presenting a prototype facilitates learning and retention of the concept shock compared with verbally enumerating the attributes of the same concept. A group of 106 students from nursing education participated in the experiment. A matched group design guided the assigning of students to different instructional conditions. The instructional program consisted of expository texts, different types of questions and feedback. In the experimental condition eight videotaped typical cases of shock were incorporated in the program. Data-analysis resulted in confirmation of the hypotheses (p less than 0.01), i.e. new instances of shock were identified more frequently by students of the experimental group, while these students were also more able to list commonalities and differences between different cases of shock. This finding supports the prototype-paradigm in concept learning and implies the recommendation to organize lessons in clinical reasoning or diagnostic behavior around typical cases of concepts.

Concept Formation↗
PubMedDate not supplied

Validation of a metabolic prototype to assist in the treatment of insulin-dependent diabetes mellitus.

This paper describes the principles and prototyping of a computer system to assist in the treatment of patients with insulin-dependent (type 1) diabetes mellitus. The system adopts a mixed approach involving rule-based qualitative algebra and a dynamic mathematical model to define the relationships between insulin dosage, diet and glycaemic response. The rule-based system (KBS), implemented in PROLOG, can be used to generate qualitative therapeutic advice. These suggestions are quantified and rank-ordered by the use of a mathematical model of glucose-insulin interaction in type 1 diabetes mellitus, with parameters adjusted for individual patients. In this paper an overview of the integrated prototype, linking the KBS and model, is provided and a case study used to demonstrate the principles of the system in operation. The results of verification and validation work performed on the KBS are described.

Blood Glucose↗
PubMed1994

Evaluation of a prototype on-line electrical conductivity system for detection of subclinical mastitis.

A prototype on-line system for measurement of electrical conductivity of quarter milk was evaluated for accuracy in detection of subclinical mastitis compared with that of bacteriological culture and SCC of sampled quarters. Because of the low quarter prevalence of mastitis, quarters were sampled conditionally from the signals of the on-line system. All signaled quarters and a random selection of the nonsignaled quarters were sampled. To calculate sensitivity and specificity, the total number of non-signaled quarters was extrapolated. The system identified correctly 18 out of 23 subclinical quarters and 521 out of 555 healthy quarters. Quarter prevalence was about 1%. Predictive value of a positive test (35%) and the predictive value of a negative test (99%) were calculated, as well as sensitivity (25%) and specificity (99%), after extrapolation of the total number of nonsignaled quarters. Because of repeated measurements, sensitivity may be underestimated. When signaled quarters were defined by repeated signals within 14 d, predictive value positive increased to 48%. The prototype on-line system did not detect subclinical mastitis very accurately because of suboptimal test characteristics.

Animals↗
PubMed1980

Characterization of the viral RNA species of prototype dengue viruses.

Dengue virus isolates have been grown in the Igarashi clone C6/36 Aedes albopictus cells in amounts suitable for biochemical studies. Oligonucleotide fingerprint analyses have been used to characterize the virion 40 S RNA species of the four prototype dengue (DEN) serotype viruses: DEN 1, Hawaiian strain; DEN 2, New Guinea C strain (both insect and mouse brain passaged derivatives); DEN 3, H-87 strain; and DEN 4, H-241 strain. Comparisons of the largest oligonucleotides derived by ribonuclease T1 digestion of these 40 S DEN virion RNA species indicate that ther are few, if any, large oligonucleotides that are homologous between any two fo the four dengue prototype strains. Preliminary analyses of the 40 S RNA 5' terminal sequence of DEN 3 virion RNA indicate that it has the composition of m7GpppAmpXp.

Aedes↗
PubMed1985

[Learning and prototype formation of artificial categories defined by multidimensional normal distributions].

In order to approximate the variety of natural categories, two kinds of stimuli whose attributes vary according to different multivariate normal distributions are generated on CRT screen. Twenty undergraduate and graduate students served as subjects. Subject's task was to discriminate the stimuli. Results revealed that subject's performance can be explained very well by the parameters of the distributions (Exp.1). Although in previous studies prototypes have been assumed to be the mean value or central tendency of category instances, there is another possibility, especially when two or more concepts are simultaneously learned, that they have attributes which are emphasized. This hypothesis was confirmed in Exp.2, using 30 undergraduates as subjects. It was argued that we must distinguish at least two kinds of prototypes: the one formed by the most frequent instances and the other the most discriminate in contrast with the other concepts.

Adolescent↗
PubMed1992

DentLE. The Dental Learning Environment: a prototype demonstration.

DentLE, the Dental Learning Environment is a hypermedia software system being prototyped as part of a research and development project at the State University of New York at Buffalo School of Dental Medicine. The design seeks to reach beyond single discipline software or cases, and integrate a range of patient problems within a comprehensive dental knowledge base. The approach is to use computer and hypermedia technology to weave together the disciplines of dentistry so that learning occurs in relation to patients, as they appear in the real world. The DentLE system prototype allows the learner to explore information in all the disciplines related to patient problems, as well as other information including "blind alleys" and results of curiosity.

Computer-Assisted Instruction↗
PubMed1991

[Hepatitis C virus: sequence homology of a European isolate and divergence from the prototype].

The polymerase chain reaction (PCR) detected specific hepatitis C viral (HCV) RNA sequences in liver biopsies from two patients with chronic hepatitis, in the tissue of a liver implantate, in plasma from four chronic non-A, non-B hepatitis (NANBH) patients and, for the first time, in an infectious anti-D-immunoglobulin preparation. A comparison of the viral sequences coding for a region for the nonstructural NS3 protein from the liver tissues revealed only a very small degree of sequence divergence on the cDNA as well as on the amino acid level (between 0 and 5%). The sequence similarities of the RNA isolated from plasma of the four chronic NANBH patients and the anti-D-immunoglobulin preparation were partly somewhat lower but altogether also high (between 90 and 100%). In contrast, all eight cDNA and amino acid sequences exhibited a significantly higher degree of divergence in comparison with the HCV prototype sequence (between 29 and 32%) than among themselves (between 0 and 10%). This unexpected high sequence similarity of the eight European isolates and their low homology to the Northamerican prototype sequence is indicative for the existence of different types of HCV. This will be important not only for epidemiological studies but also for the development of effective diagnostic procedures and vaccines. Concerning the pathogenesis of NANBH, a double infection or a helper mechanism has to be considered: in addition to the C virus, sequences of an other virus particle were found in the infectious IgG preparation as well as in the liver biopsies.

Amino Acid Sequence↗
PubMed1991

CD-ROM prototype applications within the Department of Veterans Affairs.

The Department of Veterans Affairs (VA) has been actively involved in examining the benefits of Compact Disc Read Only Memory (CD-ROM) to its operations. Approximately twenty VA titles either have been produced or are scheduled for production by Summer of 1991. Both textual and database CDs have been prototyped. Several of the CDs have been integrated directly into the VA's MUMPS-based hospital information systems. Titles which contain patient information employ the Data Encryption Standard (DES) for sensitive information. A related project involves the installation of a system which allows common VDTs on the hospital system to access commercial CDs such as MEDLINE, PDR, and CCIS. The prototypes have been successful and very favorably received by users.

CD-ROM↗
PubMed1991

AI/Consult: a prototype directed history system based upon the AI/Rheum knowledge base.

An expert system is designed which uses the AI/Rheum knowledge base as the basis for a directed workup system for rheumatological disorders. A Turbo Pascal prototype is demonstrated which, unlike AI/Rheum, permits entry by the clinician of a patient's chief complaint(s) and subsequently develops a dynamic differential diagnosis for this limited set of findings. The system restricts its line of questioning to those pertinent in order to rule in or rule out items on this dynamic differential diagnosis, and, unlike AI/Rheum, it provides immediate notification to the user when a critical mass of information has been entered in order to meet a diagnosis at one of the AI/Rheum criteria table's three levels of diagnosis (possible, probable, definite). Thus the system allows for a more rapid, focused decision making approach than does AI/Consult, while it follows the trend established by QMR in that it abandons the Greek Oracle problem solving approach and instead adopts a physician-assisted hypothesis investigation approach. The system is currently a prototype, without AI/Rheum's page oriented and mouse driven interface, and thus the total user interaction time may be longer than with AI/Rheum even though fewer user interactions (responses) are required. Plans for future development include optimization of the knowledge base to allow for more efficient, problem oriented questioning and modification of the knowledge base compiler in order to dynamically rule out diseases through the addition of three new levels of diagnosis in the knowledge base criteria tables.

Diagnosis, Computer-Assisted↗
PubMedDate not supplied

Emergence of highly pathogenic virus during selective chicken passage of the prototype mildly pathogenic chicken/Pennsylvania/83 (H5N2) influenza virus.

The prototype mildly pathogenic A/chicken/Pennsylvania/21525/83 (H5N2) avian influenza virus, which was isolated more than 5 months before the emergence of highly pathogenic virus in the major 1983 Pennsylvania outbreak, was examined for the presence of minority subpopulations of highly pathogenic virus. Selective serial passage of the parental mildly pathogenic virus in leghorn hens did not lead to recovery of highly pathogenic virus. However, several highly pathogenic reisolates were recovered from hens inoculated with either of two mildly pathogenic virus clones selected for their ability to efficiently produce plaques in trypsin-free chicken embryo fibroblasts. Unlike the parental virus, these reisolates caused high mortality in chickens and produced postmortem lesions typical of highly pathogenic avian influenza. Electrophoretic mobilities of the hemagglutinin glycoproteins of the highly pathogenic derivatives resembled those of the prototype highly pathogenic A/chicken/Pennsylvania/1370/83 (H5N2) virus isolated in October 1983. These results suggest that unrecognized subpopulations of highly pathogenic virus may have infected Pennsylvania chickens for several months before emerging as the clinically manifest component of the virus population.

Animals↗
PubMed1991

Chemically induced tumors in transgenic mice carrying prototype human c-Ha-ras genes.

Three independent transgenic mouse lines carrying human prototype c-Ha-ras genes were established. Approximately 50% of the transgenic offspring of these lines developed spontaneous tumors within 18 months. Types of tumors were restricted to angiosarcomas, skin papillomas and lung or Harderian adenocarcinomas. Interestingly, all angiosarcomas (16/16) had point mutations at the 61st codon of the transgenes. Furthermore, they were also very susceptible to the chemical carcinogens, N-methyl-N'-nitrosourea (MNU) and dimethyl-benzanthracene (DMBA). Within 12 weeks after administration of MNU, the transgenic mice developed forestomach papillomas and then carcinomas very frequently, at the rate of almost 100% and almost all of the tumors had point mutations in their transgenes at the 12th codon from GGC (Gly) to GAC (Asp). All the carcinomas of the forestomach, lung and spleen induced by DMBA had point mutations at the 61st codon from CAG (Gln) to CTG (Leu). Because no somatic point mutations in the transgenes have ever been detected in normal tissues of the affected mice, these mutations seemingly activated the human prototype c-Ha-ras transgene. From these results, it is suggested that the somatic mutation of the human c-Ha-ras transgene plays a causative role in the occurrence of natural tumors and those induced by MNU or DMBA administration in transgenic mice. This transgenic mouse provides a unique screening system for chemicals that induce or suppress the tumorigenesis.

Animals↗
PubMedDate not supplied

The Corneal EyeSys System: accuracy analysis and reproducibility of first-generation prototype.

The EyeSyS Corneal Topography System manufactured by EyeSys Laboratories, Inc., Houston, Tex utilizes a unique data-acquisition design to perform rapid, cost-effective quantitative photokeratoscopy. We evaluated a first-generation prototype system. Repeated testing with this prototype demonstrated an accuracy and reproducibility to within 0.25 D on spherical surfaces. Similar results were obtained in testing aspherical surfaces without refocusing. Data from preliminary clinical studies are displayed for the following corneal conditions: normal, keratoconus, post-keratoplasty, and post-keratoplasty with wound ectasia. Advantages of the EyeSys System include rapid data analysis and display, ease of operation, and compact table-top size.

Adult↗
PubMed1979

Abstraction of prototypical information by adults and 10-month-old infants.

The primary purpose of this study was to investigate whether preverbal infants, when presented with exemplars of an artificially constructed category, would abstract a prototypical representation of the category, and if so, whether this representation was formed by either "counting" or "averaging" the features that were varying among category members. Two experiments are reported. In Experiment 1, a set of stimuli was developed and tested for which it was demonstrated that adult subjects would readily abstruct either a modal or an average prototypical representation. The type of representation abstracted was found to be dependent on the discriminability of the feature values. In Experiment 2, 10-mo.-old infants were tested using a habituation paradigm with the stimuli developed in the first experiment. The results of this study indicated that the infants were also able to abstract the featural information that was varying among the exemplars of the category, and the infants formed an internal represenatation of the category by averaging feature values. Thus, the results clearly imply that infants are able to constructively process visual information and hence take a more active role in category formation than had been previously believed.

Adult↗
PubMed1994

Prototyping a genetics deductive database.

We are developing a laboratory notebook system known as the Genetics Deductive Database. Currently our prototype provides storage for biological facts and rules with flexible access via an interactive graphical display. We have introduced a formal basis for the representation and reasoning necessary to order genome map data and handle the uncertainty inherent in biological data. We aim to support laboratory activities by introducing an experiment planner into our prototype. The Genetics Deductive Database is built using new database technology which provides an object-oriented conceptual model, a declarative rule language, and a procedural update language. This combination of features allows the implementation of consistency maintenance, automated reasoning, and data verification.

Animals↗
PubMed1994

Oncogenic activation of human R-ras by point mutations analogous to those of prototype H-ras oncogenes.

R-ras, K-rev-1/rap and TC21, are more closely related to prototype H-ras than any other known members of the ras superfamily. We recently isolated a mutationally activated TC21 oncogene from a human ovarian carcinoma cell line. Based upon these observations, we sought to re-examine the transforming potential of R-ras, which was reported earlier to lack transforming capacity. Mutations were introduced into the R-ras gene at codons 38 or 87, analogous to positions 12 and 61, respectively, responsible for H-ras oncogene activation. While both mutations resulted in acquisition of R-ras transforming capacity for NIH3T3 cells the position 61 was shown to be more active. Transfectants expressing either R-ras mutant formed colonies in soft agar and were tumorigenic in vivo. As has been reported for H-ras, R-ras cooperated with c-raf-1 in inducing transformation of NIH3T3 cells. These results imply interactions in R-ras and c-raf-1 signaling pathways. We observed R-ras transcripts of 4.6 and 1.2 kb ubiquitously expressed in each of a variety of tissues examined. All these findings raise the possibility that R-ras, like prototype ras genes, may be mutationally activated as an oncogene in some human malignancies.

3T3 Cells↗
PubMed1994

Oxygen performance of a prototype nonconventional hydrogel.

UNLABELLED: INTRODUCTION. Oxygen permeability (Dk) of available hydrogel materials used for soft contact lenses is currently restricted by the oxygen permeability of water at 80 Dk units. A predicted upper limit for conventional hydrogels amenable for use as a contact lens, has been 37 Dk units obtained with a water content of 80%. Methods for increasing oxygen permeability beyond that determined by water content must be explored, in order to further advance the physiological compatibility of hydrogel contact lenses. METHODS: Oxygen transport characteristics of a prototype nonconventional hydrogel contact lens material were derived in terms of human equivalent oxygen percentage (EOP) and thickness (L). The oxygen permeability of the material and oxygen transmissibilities (Dk/L) of various thicknesses were computed on the bases of a recently published nonlinear EOP vs. Dk/L relationship. RESULT: The material's oxygen permeability (Dk) was determined to be approximately 35 Dk units compared to 12.7 Dk units calculated for a conventional gel material having the same water content (52% H2O). Oxygen permeability equivalent to that obtained with high-water conventional gels was achieved using this mid-water nonconventional hydrogel. The prototype material was apparently also capable of low critical thicknesses typical of low-water conventional gels. DISCUSSION: Should new gel materials be durable with critical thicknesses in the "ultra-thin" range, nonconventional gel lenses could be capable of super and perhaps even hyper transmissibility with central minus lens EOP between 15-18.5% and Dk/L between 50-90 Dk/L units. The conventional relationships between water content and oxygen transmissibility of hydrogel contact lenses appear to have been surpassed. However, significant additional hurdles have yet to be overcome before nonconventional hydrogel materials can be ready for the ophthalmic marketplace.

Biocompatible Materials↗
PubMed1995

The informatics superhighway: prototyping on the World Wide Web.

We have experimented with developing a prototype Surgeon's Workstation which makes use of the World Wide Web client-server architecture. Although originally intended merely as a means for obtaining user feedback for use in designing a "real" system, the application has been adopted for use by our Department of Surgery. As they begin to use the application, they have suggested changes and we have responded. This paper illustrates some of the advantages we have found for prototyping with Web-based applications, including security aspects.

Computer Communication Networks↗