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At least 1,297 records · Page 72Linked to original sources
PubMed2004

Use of novel nonfluoroscopic three-dimensional electroanatomic mapping system to monitor and analyze heart surgery in animal models.

BACKGROUND: The new method of three-dimensional (3D) electroanatomic mapping was presented as an important tool for cardiac imaging and intervention. We present herein the first use of this technology for the monitoring, analysis, and development of cardiac surgery at the preclinical stage. METHODS: The method is based on utilizing a locatable catheter connected to an endocardial mapping and navigating system, to accurately establish the location and orientation of the tip of the mapping catheter and simultaneously record its local electrogram. The 3D geometry of the beating cardiac chamber is reconstructed in real time. The system was tested on six goats that underwent dynamic cardiomyoplasty. Two maps of each animal were performed: preoperative and postoperative during the stimulation protocol of the skeletal muscle. RESULTS: The electroanatomic mapping system provided detailed maps of the left ventricle during the stimulation protocol, which demonstrated a striking geometric difference between the assisted and the unassisted beats. These geometric changes are best described by referring to left ventricular long-axis movements (22.3 +/- 3.8 degrees vs 3.4 +/- 1.6 degrees, p < 0.001), center-of-mass movements (10.4 +/- 3.0 mm vs 3.9 +/- 1.6 mm, p < 0.005), and the changes in upward movement viewed along the base (7.9 +/- 1.9 mm vs 3.6 +/- 1.7 mm, p < 0.01), middle (13.8 +/- 4.0 mm vs 7.3 +/- 1.8 mm, p < 0.005), and the apex of the heart (28.1 +/- 4.5 vs 5.3 +/- 2.3 mm, p < 0.001) [mean +/- SD]. CONCLUSIONS: The 3D electroanatomic mapping system allows detailed reconstruction of the left ventricular geometry and a clear view of the difference between the assisted and the unassisted beats. This novel monitoring system may serve as an important tool for the analysis and development of new techniques in cardiac surgery.

Animals↗
PubMed1988

Comparison of stationary vs ambulatory 24-hour pH monitoring recording systems.

Twenty-four-hour pH monitoring of the esophagus is frequently performed to assess gastroesophageal reflux. We performed a prospective study to determine if results obtained from stationary and ambulatory pH recording systems are comparable. Two groups of patients were studied. Group I consisted of 12 patients monitored simultaneously by both a stationary and an ambulatory pH recording system, each system having a separate pH and reference electrode. In group II, in order to eliminate electrode variability, 10 patients were monitored simultaneously with both systems and a common single pH and reference electrode. In group I, significant correlations were found in six reflux parameters measured and in the 24-hr composite score (r greater than or equal to 0.8722). However, in three of the 12 patients, marked discrepancies were noted in the composite score calculated by the stationary and ambulatory recording systems. Small variations in the pH level recorded by different pH electrodes may have accounted for the discrepancies. In group II, where electrode variability was eliminated, a better correlation was noted between all parameters measured (r greater than or equal to 0.991), and no discrepancies were noted between calculated composite scores. We concluded that the stationary and ambulatory recording systems tested are comparable in measuring 24-hr esophageal pH.

Adult↗
PubMed1999

Field method for monitoring blood glucose in beef cattle.

The purpose of this study was to determine the applicability of the Accu-Chek Easy (ACE) human self-monitoring system for monitoring glycemic status in cattle. The ACE method was compared with the Yellow Springs Instrument (YSI) analytical laboratory method in two studies. A preliminary study (62 samples) and a primary study (434 samples) involved a nine-fold range and a 10-fold range, respectively, of glucose concentrations obtained during the acute phase response of growing beef cattle to injections of varying dosages of endotoxin. The ACE monitoring method compared with the YSI analytical method resulted in similar patterns of glucose concentration change, similar ranking of glucose means across endotoxin dosages during hyper-and hypoglycemia, and a close relationship between paired YSI and ACE concentrations from common samples. The ACE method identified all nine animals that displayed hypoglycemic distress during the acute phase response to endotoxin injection. The relationship between the YSI analytical method and the ACE monitoring method was found to be nonlinear (YSI = -38.2+13.6.ACE.50; R2 = .99; Sy.x = 7.3 mg/dL), and the use of this equation to predict YSI values from ACE values in an independent data set resulted in linearity when YSI was regressed on the predicted YSI values (YSI = -.78+1.00. Predicted YSI; R2 = .87; Sy.x = 6.9 mg/dL). Even though variation seemed greater for ACE than for YSI, we concluded that a system developed for human self-monitoring of blood glucose, such as the ACE, can be used to monitor the glycemic status of cattle.

Animals↗
PubMedDate not supplied

The use of laboratory tests in diagnosis and monitoring of systemic lupus erythematosus.

Clinical immunology laboratories play an essential role in diagnosis and monitoring of systemic lupus erythematosus (SLE). To obtain the best results in terms of diagnostic performance and clinical usefulness, the following recommendations should be fulfilled: Indirect immunofluorescence on Hep-2 cells remains the method of choice for the detection of anti-nuclear antibodies (ANA). The sensitivity of ANA test for SLE is very high (almost 100%) but its specificity low since ANA can be present in a number of different clinical conditions and even in normal controls. Anti-dsDNA antibodies are highly specific for SLE and present in a high proportion of SLE patients (40-80%). The method of choice for anti-ds DNA is the Farr assay; however, the necessity of using radioactive material decreases its applicability. As an alternative, immunofluorescence on Crithidia Luciliae can be used in the diagnostic phase for its high specificity. It is not advisable to use ELISA, in the diagnostic phase, due to its low specificity. The quantitative determination of anti-dsDNA is useful for monitoring patients, in particular in the presence of nephritis. For monitoring, a quantitative method should be used (Farr assay or ELISA). The detection of antibodies to extractable nuclear antigens (ENA) and to phospholipids (Lupus anticoagulant and anti-cardiolipin antibodies with a beta2 glycoprotein I-dependent method) are useful to identify subgroups of patients at risk for some clinical manifestations (i.e. anti-phospholipid syndrome). New assays (anti-C1q and anti-nucleosome antibodies) have been recently proposed for diagnosis (anti-nucleosome) and monitoring SLE patients (anti-C1q and anti-nucleosome antibodies), with promising results. Among biological parameters, urinary levels of monocyte chemoattranct protein 1 (MCP1) seem to be the most useful to monitor nephritis activity in lupus patients.

Clinical Laboratory Techniques↗
PubMed1977

Evaluation of computer-aided monitoring of patients after heart surgery.

The medical and economic benefits of a computer-aided monitoring system were evaluated in a prospective, randomized study of 810 patients after open-heart surgery. The design of the study separated benefits of systematized postoperative care from benefits unique to the computer system and established measurable criteria by which computer-aided monitoring systems could be objectively evaluated. Criteria for comparison included the rapidity, safety, and smoothness of convalescence and time spent for various nursing activities. The study showed that the computer-aided monitoring system did not provide discernible medical benefits nor favorably affect nursing activities. Downtime of the system averaged 1 day per week. Reliability and accuracy of the system were inadequate and the benefit/cost ratio was low. Future development of computer-aided monitoring systems for open cardiac surgery should stress reliability, accuracy and relevance of the monitored measurements.

Cardiac Surgical Procedures↗
PubMed2001

Diffusional behaviour of metals in a passive sampling system for monitoring aquatic pollution.

Passive sampling systems are an emerging technology for detecting pollutants in the aquatic environment. A passive sampling system has been developed based on diffusion through a porous surface to a receiving phase, where the analyte is removed by chelation at a solid phase. The diffusion process can be described by Fickian diffusion through the sampler. The sampler has a well-defined surface area, which permits calibration in terms of concentration. Passive sampling systems can be used to determine pollutant concentrations if the diffusion process can be described and understood within environmental limits. In natural water systems, diffusion coefficients for metal transport across the porous membrane will be affected by external conditions, including biofouling and variation in turbulence and temperature. Uptake rates for the analytes Cu, Cd and Pb have been determined for the complete passive sampling system. Two different cases have been investigated, a batch case, where the bulk concentration decreases with time, and a flow-through case, where the bulk concentration remains constant. Diffusion coefficients were determined for the two conditions and compared with the calculated value obtained for the Stokes-Einstein equation in pure water. Diffusion coefficients for metals were found to be lower than for diffusion in pure water, a difference attributed to the effect of the porous membrane. The effect of the hydraulic conditions on the metal diffusion was studied for both a conventional magnetic stirrer creating turbulence in the system and for a rotated sampler, the latter providing a well-defined boundary layer system. The boundary layer was found to be negligible compared with the diffusion limiting membrane in the presence of sufficient turbulence or if the rotation of the sampler was high.

Calibration↗
PubMed1985

A new ambulatory system for extended esophageal pH monitoring.

A new 24-h ambulatory esophageal pH monitoring system (AMBI 24) was evaluated in 72 pediatric patients with suspected gastroesophageal reflux (GER). Forty-seven of these patients were monitored at home and the other 25 in our hospital. This system was employed without complication in infants and a full range of pediatric patients, as well as in older children with severe psychomotor delay. The data obtained were consistent with those reported utilizing standard monitoring equipment, and the results served as the basis for subsequent medical management. The results of this study, therefore, suggest that this method of esophageal pH monitoring is a safe and effective means of evaluating GER while allowing for patient mobility.

Adolescent↗
PubMed2001

An integrated system for significant anaesthetic events monitoring.

Patient safety assessment in anaesthesia increasingly relies on the monitoring of frequent but merely undesirable events, like hypotension. We report on the design and implementation of such a monitoring system, where 8032 patients were included over a three years period. Thirty two 'Significant Anaesthetic Events' were defined and their occurrence was routinely collected for each patient. A total of 2106 significant anaesthetic events were reported. The data were analysed using control charts, which showed that an undesirable event was recorded in 1 out of 4 interventions. The control chart showed that the incidence of significant anaesthetic events was out of the expected boundaries during one month. The system sensitivity to change in the frequency of significant anaesthetic events was investigated by a controlled intervention, designed to increase the incidence of bradycardia by changing anxyolitic medication. During the intervention, the incidence of bradycardia doubled, while the incidence of other undesirable events was not affected. The system described for the collection of significant anaesthetic events was easy to set up, sensitive to changes and provided valuable tools in performance monitoring.

Anesthesia↗
PubMed1978

Plants as bioassay systems for monitoring atmospheric pollutants.

Plant species act as natural bioindicators of atmospheric pollutants. Plants can be used as bioassay systems for monitoring atmospheric pollutants. Plant injury symptoms, altered growth and reproductive pattern, changes in yield and/or productivity, and changes in species distribution can be used singly or in combination as monitoring devices. The results must be accepted as semiquantitative, but within that constraint, air quality can be sufficiently well defined to enable the setting of air quality standards. Genetic variability of higher plant species has yielded cultivars which display a range of tolerance to gaseous and particulate atmospheric pollutants. Asexual propagation of these cultivars provides pollutant-sensitive and pollutant-tolerant plant material which can be grown on selected sites for observation. Gymnosperm and Angiosperm species as well as species of lichens and mosses have been used to establish field monitoring networks in Europe, Canada, and the United States. White pine, shade tobacco, mosses, and lichens have proven particularly useful as bioassay tools. Pollen from pollutant-sensitive and pollutant-tolerant plant cultivars has also been used as a sensitive laboratory bioassay tool for studying air quality. Epiphytic mosses are particularly efficient as monitors of particulate pollutants, especially heavy metals, some of which may act as chemical mutagens. The cost, complexity, and lack of reliability of instrumented systems for air quality monitoring make imperative the need to develop successful plant bioassay systems for monitoring air quality.

Air Pollutants↗
PubMed1997

Development of a fuzzy logic based system to monitor the electrical responses of nerve fiber.

A fuzzy logic based control system to monitor and control the electrical and chemical responses of nerve fibers has been designed and simulated. Fuzzy logic provides powerful reasoning mechanisms for combining information from multiple fuzzy sets.... The rule base has been developed based on the difference between the measured value and the desired value. The potential difference across each nerve fiber and the current through it has been monitored and controlled by a feedback control signal. The controller has been tested and simulated using sinusoidal and square wave forms with different frequency. The desired value was reached very rapidly. The system is capable of monitoring and controlling four nerve fibers simultaneously and allow the researcher to select different modes of operations.

Electrophysiology↗
PubMed2005

Improvement of the bioluminescence reporter system for real-time monitoring of circadian rhythms in the cyanobacterium Synechocystis sp. strain PCC 6803.

Circadian rhythm is a self-sustaining oscillation whose period length coincides with the 24-hour day-night cycle. A powerful tool for circadian clock research is the real-time automated bioluminescence monitoring system in which a promoter region of a clock-controlled gene is fused to a luciferase reporter gene and rhythmic regulation of the promoter activity is monitored as bioluminescence. In the present study, we greatly improved the bioluminescence reporter system in the cyanobacterium Synechocystis sp. strain PCC 6803. We fused an 805-bp promoter region of the dnaK gene seamlessly to the luxA coding sequence and integrated the P(dnaK)::luxAB fusion gene into a specific intergenic region of the Synechocystis genome (targeting site 1). The resulting new reporter strain, PdnaK::luxAB(-), showed 12 times the bioluminescence intensity of the standard reporter strain, CFC2. Furthermore, we generated strain PdnaK::luxAB(+), in which the P(dnaK)::luxAB fusion gene and the selection-marker spectinomycin resistance gene are transcribed in opposite directions. The PdnaK::luxAB(+) strain showed 19 times the bioluminescence intensity of strain CFC2. The procedures used to increase the bioluminescence intensity are especially useful for bioluminescence monitoring of genes with low promoter activity. In addition, these reporter constructs facilitate bioluminescence monitoring of any gene because the promoter fragments they contain can easily be replaced by digestion with unique restriction enzymes. They would therefore contribute to a genome-wide analysis of gene expression in Synechocystis.

Circadian Rhythm↗
PubMed2002

Cutting-edge technology. III. Imaging and the gastrointestinal tract: mapping the human enteric nervous system.

Monitoring membrane potentials by multisite optical recording techniques using voltage-sensitive dyes is ideal for direct analysis of network signaling. We applied this technology to monitor fast and slow excitability changes in the enteric nervous system and in hundreds of neurons simultaneously at cellular and subcellular resolution. This imaging technique presents a powerful tool to study activity patterns in enteric pathways and to assess differential activation of nerves in the gut to a number of stimuli that modulate neuronal activity directly or through synaptic mechanisms. The optical mapping made it possible to record from tissues such as human enteric nerves, which were, until now, inaccessible by other techniques.

Digestive System↗
PubMed1990

Therapeutic drug monitoring analysis systems for the physician office laboratory: a review of the literature.

Commercially available systems for therapeutic drug monitoring in the physician office laboratory (POL) are reviewed. The Abbott Vision, Kodak Ektachem, Syntex AccuLevel, Syva Emit QST, Ames Seralyzer ARIS, and Ames Clinimate ARIS have been found to be sensitive and accurate compared with more conventional laboratory assays, and are well-suited for the POL. The number of available drug assay is very limited with every system except the QST. The QST offers a large menu and would be appropriate for large practices. The Abbott TDx or other semiautomated system usually found in the clinical chemistry laboratory may be particularly useful and cost-effective in office practices with a large volume of specimens. AccuLevel or ARIS might be the best choices for clinics or pharmacies that generate few samples. The start-up time is the longest with the Vision and Ektachem systems (30 minutes). Most systems have the capacity to produce results within one to five minutes with the exceptions of the Vision (13 minutes for theophylline) and AccuLevel (20 minutes). The Vision is the most automated system and both AccuLevel and the Vision use whole blood, thereby bypassing the additional time required for centrifugation of the patient specimen. The Ektachem, Vision, and QST have an operator-independent pipetting step that offers a significant advantage when operated by semiskilled personnel. Although the AccuLevel eliminates the need for a large initial capital expenditure, the individual cost per test is higher. Leasing programs are available or certain systems. Increased government regulation will improve the quality control of therapeutic drug monitoring in the POL.

Clinical Laboratory Techniques↗
PubMed2000

Unconstrained physiological monotoring in daily living for health care.

This paper deals with the recent development of two types of non-invasive physiological monitoring systems for possible application in an unconstrained manner to normal subjects for health care as well as to patients and/or outpatients with disorders or with life support systems (artificial organs and organ transplantations). One is an ambulatory monitoring system which allows automatic acquisition of blood pressure, cardiac output and other cardiovascular hemodynamic parameters on a beat-by-beat basis using the volume-compensation and transthoracic electrical admittance method. The other is a home monitoring system installed in a lavatory which can measure body and excreta weight together with the ballistocardiogram as an index of cardiac ejecting function in an unaware fashion without attachment of any sensors to the subject's body and without special operations for measurement during toilet use. Outlines of these two systems and monitoring results of laboratory and field testings are presented, and these suggest that the ambulatory and non-conscious physiological monitoring techniques described herein appear promising as a valuable and helpful means for use in research as well as in the practical field of health monitoring at home during daily living.

Activities of Daily Living↗
PubMed2006

Cre reporter system to monitor the translocation of type III secreted proteins into host cells.

Central to the study of type III secretion systems is the availability of reporter systems to monitor bacterial protein translocation into host cells. We report here the development of a bacteriophage P1 Cre recombinase-based system to monitor the translocation of bacterial proteins into mammalian cells. Bacteriophage P1 Cre recombinase fused to the secretion and translocation signals of Salmonella enterica serovar Typhimurium of the type III secreted protein SopE was secreted in a type III secretion system-dependent fashion. More importantly, the SopE-Cre chimera was translocated into host cells via the type III secretion system and activated the expression of luciferase and green fluorescent protein reporters of Cre recombinase activity.

Animals↗
PubMed1989

Incidence, physiologic description, compensatory mechanisms, and therapeutic implications of monitored events.

We described 663 unanticipated monitored circulatory events in 247 high-risk surgical patients by simultaneous invasive and noninvasive hemodynamic and oxygen transport monitoring systems. Unanticipated monitored events were defined as sudden reductions (greater than 20%) in cardiac index (CI), PaO2, SaO2, transcutaneous PO2 (PtcO2), and PtcO2/PaO2 index, or decreases to the lower limits of satisfactory values, specifically: PaO2 less than 70 torr, SaO2 less than 95%, PtcO2 less than 50 torr, and PtcO2/PaO2 less than 0.6. Essentially, monitored events are the small variations superimposed on the overall physiologic patterns that describe the entire course of critical illnesses. Monitored events are described by their baseline values just before each event, at the nadir of the event, and at the recovery from the event. To simplify presentation of complex changes in many variables, the circulatory changes were evaluated in terms of cardiac, pulmonary, and peripheral perfusion functions. Common patterns of these monitored events and the incidence of these patterns in high-risk surgical patients were described. Before the unanticipated monitored event, there were normal or increased heart, lung, and perfusion functions in about three fourths of the events. At the nadir, cardiac functions decreased in about two thirds, perfusion decreased in over half, and lung function fell in only one quarter of the events. Recovery occurred with increased cardiac function in two thirds, improved perfusion in over half, and increased lung function in less than one fifth of these monitored events. Noninvasive and invasive hemodynamic and oxygen transport variables were measured simultaneously to evaluate compensatory and decompensatory patterns.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Gas Analysis↗
PubMed2005

Transgene dispersal through pollen.

Techniques used for the transfer of novel genes into host plant genomes have created new possibilities for crop improvement. The implementation of transgenic crop species into agriculture has introduced the possibility of transgene escape into the environment via pollen dispersal. Although the movement of pollen is a critical step in transgene escape, there is currently no system to monitor transgenic pollen movement under field conditions. The development of an effective in vivo monitoring system suitable for use under field conditions is needed for research and commercial purposes so potential risks can be quantified and evaluated. This chapter describes the development of a model system using green fluorescent protein (GFP) expression in pollen as a marker to monitor pollen distribution patterns. A pollen specific promoter was used to express the GFP gene in tobacco (Nicotiana tabacum L.). GFP was visualized in pollen and growing pollen tubes using fluorescent microscopy. Furthermore, the goal of this research was to compare the dynamics of pollen movement with that of gene flow by using another method of whole plant expression of GFP to estimate out-crossing frequencies by progeny analysis. Pollen movement and gene flow were quantified under field conditions. Pollen traps were collected and screened for presence of GFP-tagged pollen using fluorescence microscopy. Progeny from wild type plants were screened with a hand held ultraviolet light for detection of the GFP phenotype.

Gene Transfer Techniques↗
PubMed1986

[A system for monitoring cancer mortality].

"This paper reports the establishment of a system for monitoring cancer mortality of individuals forming approximately a 10 percent sample of the Canadian labour force. Computerized record linkage was used in conjunction with the Canadian mortality data base maintained by Statistics Canada to determine the mortality experience of the cohort between 1965 and 1979. Selected results are presented, some of which appear to indicate associations between the occupation and cause of death, and others of which seem likely to indicate the influence of lifestyle factors such as smoking and diet. Cancer mortality is also presented by social class." (SUMMARY IN ENG AND SPA)

Americas↗