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At least 721 records · Page 40Linked to original sources
PubMed1988

Validation of an ambulatory esophageal pH monitoring system.

The present study documents the accuracy of a commercially available ambulatory esophageal pH instrument. The distal esophagus of five subjects with daily heartburn was monitored for 24 h in the laboratory via an antimony pH electrode. The computer output from the ambulatory unit was compared to the on-line recording in terms of all events in which the pH dropped below four. A signal detection model was used, with an on-line pH tracing serving as the criterion response. The events noted as true positives (80%) were an accurate representation by the computer output of the events of pH less than four displayed by the on-line recording. The processing done by this particular ambulatory system tends to actually "ignore" transient pH drops (18% false negatives) and, may, in fact, provide more physiologically meaningful information than hardwired analog techniques for 24-h pH monitoring. The results confirm that ambulatory pH monitoring can produce meaningful and reliable physiological data concerning gastroesophageal reflux.

Adult↗
PubMed1998

Quantitative measurement of serum HCV RNA in patients with chronic hepatitis C: comparison between Amplicor HCV monitor system and branched DNA signal amplification assay.

Quantitative measurement of serum hepatitis C virus (HCV) RNA is important in predicting and monitoring the therapeutic effects of interferon in treating patients with chronic hepatitis C. We compared two commercial available assays, Roche Amplicor HCV Monitor test kits and Chiron branched DNA signal amplification (bDNA) assay, in quantitative measurement of serum HCV RNA in 74 patients with chronic hepatitis C. The serum HCV RNA of each of these patients was qualitatively positive by conventional reverse transcription-nested polymerase chain reaction. Serum HCV RNA was detected positive by the Amplicor test kits in 63 (85%) patients and by the bDNA assay in 58 (78%) patients (P > 0.05). The quantitative results of HCV RNA detected by both assays showed a good linear correlation (r = 0.56, P < 0.001). Amplicor test kits detected 5 patients with low viremia which were below the detection limit of the bDNA assay (2.0 x 10(5) genome equivalents/ml). However, the mean HCV RNA values detected by the Amplicor test kits was 1.26 log lower than that of the bDNA assay. The Amplicor test kits detected only 5 samples (8%) with a HCV RNA value greater than 5 x 10(6) copies/ml, while the bDNA assay detected 23 samples (40%) with a HCV RNA value greater than 5 x 10(6) genome equivalents/ml (P < 0.01). HCV genotype did not affect the positive rate of HCV RNA measurement detected by both assays. However, a significantly higher mean serum HCV RNA value was noted in HCV genotype 1b as compared with the other genotypes. We concluded that the Roche Amplicor HCV Monitor test kits and the Chiron branched DNA signal amplification assay are equally sensitive in the quantitative measurement of serum HCV RNA in patients with chronic hepatitis C and can be reliably used in measuring HCV viremia clinically.

Female↗
PubMed1993

The dehydrogenase assay with resazurin: practical performance as a monitoring system and Ph-dependent toxicity of phenolic compounds.

The dehydrogenase assay with resazurin as an oxidoreduction dye was used for monitoring the performance of six laboratory-scale sewage treatment plants. The dehydrogenase activity measured proved to be a reliable monitoring parameter, although it did not always positively correlate with the simultaneously estimated respiration activity. With the help of the dehydrogenase assay, the toxicity of different phenolic compounds was determined. It was found that the toxicity of 2.4-dichlorophenol, 3.5-dichlorophenol, and 2.4-dinitrophenol was clearly dependent on the pH. These data were supported by shock loading experiments in laboratory-scale sewage treatment plants.

Biological Assay↗
PubMed1999

Seroprevalence of Trichinella infection in domestic swine based on the National Animal Health Monitoring System's 1990 and 1995 swine surveys.

Swine sera collected by the US Department of Agriculture's Center for Animal Health Monitoring during 1990 and 1995 was tested for antibodies to Trichinella spiralis using an enzyme immunoassay. From a total of 3048 sera collected from lactating sows in 1990, five sera tested positive for a prevalence of 0.16%. From a total of 7987 sera collected from both finishing pigs and gestating sows in 1995, one serum was positive for a prevalence of 0.013%. Responses to questionnaires administered at the time of serum collection showed that seropositive farms had management variables consistent with known risk factors for exposure to trichinae.

Animal Husbandry↗
PubMed2001

A fracture movement monitoring system to aid in the assessment of fracture healing in humans.

This paper presents a new design for a device to monitor the motion of fracture fragments in diaphyseal tibial fractures. The device measures the motion that occurs at the fracture site when loaded by gait or by manipulation. It has undergone rigorous calibration and acceptance trials. The device has been used in ethically approved research clinics held at the North Staffordshire Hospital (40 patients). The paper presents a selection of results obtained using the new device. The results demonstrate several new ways of assessing fracture healing by examining fracture site motion. The following conclusions were drawn: 1. If fracture monitoring devices are to be attached to bone screws, it is essential to minimize bone screw errors. To do this, each patient must have similar bone screw lengths, orientations, alignment and siting. This is only achievable using a peroperative reduction device. 2. If fracture stiffness is to be used as a measure of fracture healing, load rate should be controlled; at the very least strain rate should be controlled. 3. It is imperative that fracture stiffness be measured in more than one plane by a biplanar device so that asymmetry may be accommodated. 4. Fracture stiffness, on its own, is probably not a sufficiently rigorous measure of healing end-point. The quantifiably viscoelastic properties of healing callus should be taken into account.

Bone Screws↗
PubMed2004

An inexpensive food cup for use in a commercially available food monitoring system.

The microstructure of feeding in rats can be probed using a variety of protocols that employ videotape-based ratings, pellet feeders, and/or laboratory balances. A recent commercial product (BioDAQ, Research Diets, New Brunswick, NJ) uses a metal food hopper placed on a load cell to monitor daily food pellet consumption. In this system, movements of the hopper during eating and the cessation of hopper movements after eating are combined with momentary hopper weights for subsequent analyses of daily meal patterns. Our laboratory has devised an improved food cup for the BioDAQ system that is easily balanced, minimizes spillage, and is compatible with either powdered chow diets or nonpelleted soft diets (e.g., a high-fat diet). In the present paper, we describe the methods used to fabricate this food cup and present data illustrating its use in meal pattern analyses for rats fed either a ground laboratory chow or a 33% high-fat diet.

Animal Feed↗
PubMed1990

A practical E-PERM (electret passive environmental radon monitor) system for indoor 222Rn measurement.

The technical and scientific basis for the measurement of indoor 222Rn concentration using an E-PERM (Electret passive environmental radon monitor) has been described in our earlier work. The purpose of this paper is to describe further development of a practical and convenient system that can be used routinely for indoor 222Rn measurement. The ion chamber is now made of electrically conducting plastic to minimize the response from natural gamma radiation. A spring-loaded shutter method is used to cover and uncover the electret from outside the chamber. The electret voltage reader has been modified to improve the accuracy and the ease in operation. The calibration, performance, error analysis, and lower limits of detection for these standardized versions of E-PERMs are also described.

Air Pollutants↗
PubMed2007

Computerized performance monitoring systems: learning and living with its limitations.

Computer technology now allows clinical administrators to collect and analyze large data sets for performance monitoring. Despite the obvious usefulness of this technology, there are limitations. The indices that we can measure are at best proxies that might correlate with good clinical care but can also become dissociated from it in a variety of ways. First, there may not be a relationship throughout the entire continuum between the indicator and what we really value. Second, change in an indicator may not be associated with comparable change in the underlying value. Thirdly, the valence of an indicator can change depending on the context. Fourth, the very act of measuring an indicator can change its valence. Although, from a research perspective there may be technical solutions to these problems, in the real world where clinical care and politics meet, this may not be possible. Indices become reified. Measures become benchmarks and benchmarks quotas. Average is not a statistical phrase but a judgment and below average a term of approbation. To maximize the benefits of computerized monitoring, administrators need to be sensitive to this political dimension.

Community Mental Health Centers↗