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PubMedDate not supplied

Quantification of object manipulation in children with cerebral palsy.

A shape-posting task was studied in 30 control, eight hemiplegic and 10 diplegic children, to determine how differences in object manipulation between such children could be quantified. Conical, cylindrical and triangular-shaped objects were posted through a hole in a perspex screen, three times each with both preferred and non-preferred hands. Four variables were defined to describe kinematic aspects of the task: adjustment inefficiency, mean transport velocity, adjustment distance to be completed in the placing phase and adjustment velocity in the placing phase. As expected, total task time was increased in subjects with cerebral palsy and with more complex shapes, and reduced by repetition. The four kinematic variables reduced the variation in task time between individual children by 79%, between sets of like objects by 62%, and the residual variation by 63%. Adjustment inefficiency was increased and mean transport velocity reduced in subjects with cerebral palsy, whereas repetition had the opposite effect. It is suggested that combined alterations in adjustment inefficiency and transport velocity reflect changes in the intrinsic uncertainty of a movement and that this quantity is decreased by repetition and increased in cerebral palsy.

Cerebral Palsy↗
PubMed1980

Quantification of spectrin-containing erythroid precursor cells in normal and perturbed erythropoiesis.

The presence of spectrin in erythroid cells of female BALB/c mice has been detected by specific antisera to spectrin, using an immunofluorescent sandwich technique. Spectrin-containing cells are more numerous in bone marrow (18.9%) than in spleen (3.7%). In marrow, spectrin-containing cells exceed benzidine positive cells by about 6.2% whereas in spleen, numbers are almost equivalent. This suggests that normal proerythroblasts and perhaps more primitive erythroid cells contain spectrin, which is consistent with cytological characteristics of some spectrin-positive cells. Proerythroblast cells from spleens of Rauscher virus induced erythroleukemic mice contain spectrin although markers for hemoglobin synthesis are absent. Changes in CFUE number are closely correlated with those of spectrin-positive erythroid cells when erythropoiesis is perturbed. In red cell transfused, erythropoietically suppressed mice undergoing hemopoietic regeneration the administration of erythropoietin results in appearance of CFUE and spectrin-positive cells within 24-72 h. Due to different methods of assaying for CFUE and presence of spectrin, numerical data cannot be compared quantitatively because of uncertainty in the level of detection. Although it is not possible to demonstrate the presence or absence of spectrin in CFUE, changes in spectrin-containing cells and CFUE are closely correlated in time. Spectrin provides a convenient marker for both normal and leukemic nucleated erythroid cells and particular provides a functional marker for proerythroblasts which have previously been identified only by morphology.

Animals↗
PubMed1996

Reproducibility of metabolite peak areas in 1H MRS of brain.

We studied the reproducibility of metabolite signals (from N-acetyl aspartate [NAA], choline, and creatine) measured with a standard single-voxel proton magnetic resonance spectroscopy technique (PRESS, TE = 135 ms, 8 ml VOI) in vitro and in two groups of normal volunteers. Spectral peak areas were quantified both by integration and by curve-fitting. In the in vitro study, the "between-days" variability (coefficient of variation [CV]) of measurements ranged from 0.9% to 2.3%. In the first group of volunteers (n = 12), single voxel spectroscopic measurements (8 ml VOI, 256 acquisitions [ACQs]) were made from mirror-image parts of the right and left hemispheres on 2 separate days. The "between-days" CV of measurements ranged from 9% to 18% for metabolite areas, and from 10% to 26% for metabolite area ratios. There were no significant differences between quantification method or hemisphere. After checking and optimising the MR scanner performance (in fact, it was virtually optimal), the second group (n = 4) each had six sequential single voxel spectroscopic measurements (each of 64 ACQs) from the right hemisphere (without moving the voxel) on each of 4 separate days. Even when the metabolites were measured from the same place in the same hemisphere sequentially six times in a 20-min period, the "within-run" CVs ranged from 4.4% to 17.2% for metabolite areas and from 9.7% to 17.0% for metabolite area ratios. The between-days CVs for the subjects ranged from 7.7% to 25.8% (metabolite areas) and from 10.1% to 22.6% (metabolite area ratios). The variability is due to a combination of random noise, subject motion, baseline artefacts in the spectra, and uncertainties in repositioning the VOIs. It is likely to represent the best reproducibility possible with 8-ml VOIs in cooperative, healthy volunteers carefully positioned on each occasion in a standard clinical scanner. Changes in metabolite levels in individuals must therefore be of the order of 20-40% before we can be reasonably confident of measuring them. Reproducibility in patients, who may be less cooperative, will probably be no better, and this must be taken into account in the interpretation of MRS studies in patients with brain pathology; for example, stroke, head injury, and tumours.

Adult↗
PubMed2006

Accuracy and reproducibility of a subpixel extended phase correlation method to determine micron level displacements in the heart.

Future treatment of heart disease may involve local perturbations of mechanical function, such as intramyocardial injections of angiogenic growth factors or progenitor cells. This necessitates an accurate measurement technique to determine regional heart function. We have previously developed a method to determine regional heart function using a phase correlation algorithm. However, in determining regional function over a single heartbeat it is necessary to sum displacements between many images. We have therefore incorporated a subpixel algorithm that models the result of phase correlation as a sinc function in order to increase the accuracy of our technique. This method, which we have named high density mapping (HDM), determines the subpixel displacement of 64 x 64 pixel regions from images of the heart. To determine the accuracy and precision of the technique, a high contrast image of a heart was digitally shifted 1, 2 or 3 pixels. The original and shifted images were then downsampled four times resulting in 0.25, 0.50 or 0.75 pixel shifts between the original and shifted images. The average accuracy of HDM in the digitally shifted images was 0.06 pixels, with a precision of 0.08 pixels. Effectiveness of HDM in characterization of deformation was also assessed in digitally stretched images. Error in quantification of strain was found to be less than 3.5% of the calculated strain. In an additional set of experiments, in which accuracy was determined using physical motion instead of digital shifting and downsampling, a speckle pattern was displaced by known distances using a micromanipulator, such that the displacement between the captured images was 0.5 pixels. These data demonstrated an accuracy of 0.09 pixels and a precision of 0.02 pixels. Finally, as HDM is used to determine the regional stroke work index (RSW) in beating hearts, the repeatability of using this method to compute RSW was assessed. RSW, the integral of intraventricular pressure with respect to unitless regional area, where end diastolic area was normalized to unity, was assessed in consecutive beats from four different hearts. The average standard deviation of RSW was 0.098 mmHg. Uncertainty analysis determined the maximum error of RSW to be +/-0.41 mmHg, approximately two-thirds of the measured biologic variability. These data demonstrate the ability of HDM to accurately and reproducibly measure displacement and regional function in the beating heart.

Algorithms↗
PubMed2002

Microwave-assisted extraction of zearalenone from wheat and corn.

A microwave-assisted extraction (MAE) method has been developed for determination of zearalenone in wheat and corn by LC-MS with an atmospheric pressure chemical ionization interface (APCI). Matrix effects were minimized by use of matrix-matched standard curves for quantification of the analyte. The limit of quantification (LOQ) of the method was 30 ng g(-1) in wheat and 20 ng g(-1) in corn. The rapid LC-MS method enabled analysis of the extracts without clean-up, thereby reducing analyte losses, the time required for the analytical procedure, and costs. A factorial design approach was used to examine the effect on extraction efficiency of the main extraction conditions - time, temperature, and solvent. On the basis of results from statistical assessment extraction was performed with 1:1 (v/v) methanol-acetonitrile at 80 degrees C for 5 min. When these extraction conditions were applied to a wheat sample from a recently conducted international proficiency test, 92% (103 ng g(-1)) of the assigned zearalenone concentration (112 ng g(-1)) in the test material was obtained. This result was within the uncertainty (u) range of the assigned value of the test material (u=+/-15.8 ng g(-1), alpha=0.05) thereby demonstrating the accuracy of the method was sufficient. The precision of the whole method was also confirmed to be adequate, because the observed relative standard deviation (RSD) of 12% (n=10) also fulfils the quality criteria recommended by European guidelines for in-house method validation.

Chromatography, High Pressure Liquid↗
PubMed2001

Quantification of major peanut allergens Ara h 1 and Ara h 2 in the peanut varieties Runner, Spanish, Virginia, and Valencia, bred in different parts of the world.

BACKGROUND: The serology of peanut allergy seems to be different in various parts of the world. We analyzed the composition of 13 samples of three varieties of peanut in order to compare their allergenic nature. METHODS: Peanut cultivars that are commonly processed in the West were analyzed for protein content, protein composition, and Ara h 1 and Ara h 2 content by biochemical methods. IgE-binding properties were analyzed by ELISA using serum from patients with documented peanut allergy. RESULTS: Total protein contents were comparable for all tested samples (24-29%), and proteins were extractable to the same extent. SDS-PAGE patterns differed slightly, but all major bands were visible in all samples (molecular masses of approximately 14100 kDa under reducing conditions). Ara h 1 and Ara h 2 were quantified by SDS PAGE densitometry and were expressed as percentage of the total protein content. Ara h 1 was in the range 12-16%, whereas Ara h 2 was 5.9-9.3%. In view of the analytic uncertainty of this determination, the content of both Ara h 1 and Ara h 2 was not significantly different between the tested samples. In an IgE-binding inhibition ELISA, the affinities of the peanut proteins for peanut-specific IgE were measured. Minor differences were observed between the tested samples, with the most potent IgE-binding sample having a two times higher ability to bind IgE than the weakest IgE-binding sample. CONCLUSIONS: The results suggest that peanuts of different varieties and from different parts of the world contain similar proteins, including Ara h I and Ara h 2. Consequently, the IgE-binding properties are similar to a great extent. This indicates that differences in the serology of peanut allergy may not originate from differences in the allergen composition of the peanut.

2S Albumins, Plant↗
PubMed2003

Comparative quantification of health risks conceptual framework and methodological issues.

Reliable and comparable analysis of risks to health is key for preventing disease and injury. Causal attribution of morbidity and mortality to risk factors has traditionally been conducted in the context of methodological traditions of individual risk factors, often in a limited number of settings, restricting comparability.In this paper, we discuss the conceptual and methodological issues for quantifying the population health effects of individual or groups of risk factors in various levels of causality using knowledge from different scientific disciplines. The issues include: comparing the burden of disease due to the observed exposure distribution in a population with the burden from a hypothetical distribution or series of distributions, rather than a single reference level such as non-exposed; considering the multiple stages in the causal network of interactions among risk factor(s) and disease outcome to allow making inferences about some combinations of risk factors for which epidemiological studies have not been conducted, including the joint effects of multiple risk factors; calculating the health loss due to risk factor(s) as a time-indexed "stream" of disease burden due to a time-indexed "stream" of exposure, including consideration of discounting; and the sources of uncertainty.

Journal Article↗
PubMed2005

Nonlinearities in source receptor relationships for sulfur and nitrogen compounds.

The relationship between emissions and deposition of air pollutants, both spatially and in time forms an important focus for science and for policy makers. In practice, this relationship may become nonlinear if the underlying processes change with time, or in space. Nonlinearities may also appear due to errors in emission or deposition data, and careful scrutiny of both data sources and their relationship provides a means of picking up such deficiencies. Nonlinearities in source receptor relationships for sulfur and nitrogen compounds in Europe have been identified in measurement data for the UK. In the case of sulfur, the dry deposition process has been shown to be strongly influenced by ambient concentrations of NH3, leading to substantial increases in deposition rate as SO2 concentrations decline and the ratio SO2/NH3 decreases. The field evidence extends to measurements over three different surfaces in three countries across Europe. A mechanistic understanding of the cause of this nonlinearity has been provided. Apparent nonlinearities also exist in the sulfur deposition field through the influence of shipping emissions. The effect is clear at west coast locations, where during a period in which land-based sulfur emissions declined by 50%, no significant decline in concentrations of SO(2-) in precipitation were observed. The sites affected are primarily the coastal regions of southwestern UK, where shipping sources contribute a substantial fraction of the deposited sulfur, but the effect is not detectable elsewhere. Full quantification of the spatially disaggregated emission and their changes in time will eliminate this apparent nonlinearity in the source-receptor data. For oxidized nitrogen emission and deposition in the UK, there is strong evidence of nonlinearity in the source-receptor relationship. The concentrations and deposition of NO(3-) in precipitation have declined little following a reduction in emissions of 45% during the period 1987 to 2001. The data imply a significant decrease in the average transport distance for oxidized nitrogen and most probably an increase in the average oxidation rate. However, the net effect of changes in aerosol chemistry due to changes in sulfur emissions and less competition for the main oxidants as a consequence of reductions in sulfur emission have not been separated. A quantitative explanation of the cause of this nonlinearity is lacking and the effects are therefore identified as an important uncertainty for the development of further protocols to control acidification, eutrophication and photochemical oxidants in Europe.

Air Movements↗
PubMed2004

Modeling data from titration, amide H/D exchange, and mass spectrometry to obtain protein-ligand binding constants.

We recently reported a new method for quantification of protein-ligand interaction by mass spectrometry, titration and H/D exchange (PLIMSTEX) for determining the binding stoichiometry and affinity of a wide range of protein-ligand interactions. Here we describe the method for analyzing the PLIMSTEX titration curves and evaluate the effect of various models on the precision and accuracy for determining binding constants using H/D exchange and a titration. The titration data were fitted using a 1:n protein:ligand sequential binding model, where n is the number of binding sites for the same ligand. An ordinary differential equation was used for the first time in calculating the free ligand concentration from the total ligand concentration. A nonlinear least squares regression method was applied to minimize the error between the calculated and the experimentally measured deuterium shift by varying the unknown parameters. A resampling method and second-order statistics were used to evaluate the uncertainties of the fitting parameters. The interaction of intestinal fatty-acid-binding protein (IFABP) with a fatty-acid carboxylate and that of calmodulin with Ca(2+) are used as two tests. The modeling process described here not only is a new tool for analyzing H/D exchange data acquired by ESI-MS, but also possesses novel aspects in modeling experimental titration data to determine the affinity of ligand binding.

Amides↗
PubMed2002

Indirect tritium determination by an original 3He ingrowth method using a standard helium leak detector mass spectrometer.

A traditional helium leak detector mass spectrometer is applied in analytical chemistry. We report its straightforward use for the precise quantification of 3He and 4He concentrations at a sub-ppb level. Repetitive external calibrations with certified gases demonstrate long-term stability, reproducibility of 3% at the ppb range, and linearity versus helium concentration over 5 orders of magnitude. The mass spectrometric determination of 3He takes into account a H3+ contribution and has a 3He detection limit of 2 ppb. Since 4He induces an attenuation effect of the mass 3 signal, this apparatus is only suitable for the measurement of 3He/4He ratio greater than 10 Ra (atmospheric ratio Ra = 1.38 x 10(-6)). This mass spectrometric technique has found novel application in the determination of tritium concentrations with an original 3He ingrowth method. Here, samples are first purified cryogenically onto activated charcoal to eliminate tritium interfering during the 3He mass spectrometric determination step. Helium is also preconcentrated, and 3He is routinely determined around 0.05 ppb with a 20% relative uncertainty. This 3He measurement technique has been successfully applied in the field of tritiated waste drums as a nondestructive method. The total amount of tritium present in these 200-L drums can be determined as low as approximately 1 GBq.

Journal Article↗
PubMed2006

Parameter sensitivity analysis for activated sludge models No. 1 and 3 combined with one-dimensional settling model.

The aim of this study was to suggest a sensitivity analysis technique that can reliably predict effluent quality and minimize calibration efforts without being seriously affected by influent composition and parameter uncertainty in the activated sludge models No. 1 (ASM1) and No. 3 (ASM3) with a settling model. The parameter sensitivities for ASM1 and ASM3 were analyzed by three techniques such as SVM-Slope, RVM-SlopeMA, and RVM-AreaCRF. The settling model parameters were also considered. The selected highly sensitive parameters were estimated with a genetic algorithm, and the simulation results were compared as deltaEQ. For ASM1, the SVM-Slope technique proved to be an acceptable approach because it identified consistent sensitive parameter sets and presented smaller deltaEQ under every tested condition. For ASM3, no technique identified consistently sensitive parameters under different conditions. This phenomenon was regarded as the reflection of the high sensitivity of the ASM3 parameters. But it should be noted that the SVM-Slope technique presented reliable deltaEQ under every influent condition. Moreover, it was the simplest and easiest methodology for coding and quantification among those tested. Therefore, it was concluded that the SVM-Slope technique could be a reasonable approach for both ASM1 and ASM3.

Algorithms↗
PubMed1986

An approach to quantification of biaxial tissue stress-strain data.

Delineation of the mechanical properties of biologic tissues is one of the cornerstones of biomechanics. Abundant data from uniaxial tests exist but these cannot be extrapolated to describe three-dimensional properties of tissue. Biaxial stress-strain studies have been performed using skin, blood vessels and pericardium. Quantitative description of tissue properties in these studies has employed either polynomial or exponential strain-energy functions. Interpretation of these data, however, is difficult because of wide variability of the estimated coefficients of these functions. This variability has been attributed to experimental noise, numerical instabilities in the algorithms, or to strain-history dependence. No systematic method has been proposed to evaluate the variability. This paper describes a statistically based approach to assessing the sources of and accounting for variability of coefficients in describing biaxial stress-strain data. Our data are from canine pericardium subjected to various combinations of simultaneous biaxial stretching. We first determine a suitable strain-energy function with the least number of free parameters that will fit the data reasonably. We then perform residual analysis to see if standard statistical methods can be used to assess the variability. If not, we use a nonparametric method called bootstrapping that is suitable for assessing the uncertainty in the coefficients. Using a five-parameter exponential strain-energy function, pericardial tissue is found to be strain-history dependent and anisotropic. These findings cannot be attributed to either experimental noise or instability in the numerical algorithms.

Animals↗
PubMed1998

Magnetic resonance quantification of the myocardial perfusion reserve with a Fermi function model for constrained deconvolution.

The myocardial perfusion reserve, defined as the ratio of hyperemic and basal myocardial blood flow, is a useful indicator of the functional significance of a coronary artery lesion. Rapid magnetic resonance (MR) imaging for the noninvasive detection of a bolus-injected contrast agent as a MR tracer is applied to the measurement of regional tissue perfusion during rest and hyperemia, in patients with microvascular dysfunction. A Fermi function model for the distribution of tracer residence times in the myocardium is used to fit the MR signal curves. The myocardial perfusion reserve is calculated from the impulse response amplitudes for rest and hyperemia. The assumptions of the model are tested with Monte Carlo simulations, using a multiple path, axially distributed mathematical model of blood tissue exchange, which allows for systematic variation of blood flow, vascular volume, and capillary permeability. For a contrast-to-noise ratio of 6:1, and over a range of flows from 0.5 to 4.0 ml/min per g of tissue, the ratio of the impulse response amplitudes for hyperemic and basal flows is linearly proportional to the ratio of model blood flows, if the mean transit time of the input function is shorter than approximately 9 s. The uncertainty in the blood flow reserve estimates grows both at low (< 1.0 ml/min/g) and high (> 3-4 ml/min/g) flows. The predictions of the Monte Carlo simulations agree with the results of MR first pass studies in patients without significant coronary artery lesions and microvascular dysfunction, where the perfusion reserve in the territory of the left anterior descending coronary artery (LAD) correlates linearly with the intracoronary Doppler ultrasound flow reserve in the LAD (r = 0.84), in agreement with previous PET studies.

Capillaries↗
PubMedDate not supplied

Quantitative radiographic imaging using a photostimulable phosphor system.

We have evaluated a photostimulable phosphor x-ray imaging system [Philips Computed Radiography (PCR) system] for use in quantification of x-ray exposure in diagnostic radiography. An exponential function was fitted to data yielding quantitative x-ray exposure values as a function of digital pixel values. We investigated several factors that affect the accuracy of exposure measurement using the PCR including repeatability, background noise as a function of time delay between plate erasure and use, sensitivity variation between different plates, nonuniformity of sensitivity within a plate, decay of the latent image between time of exposure and readout (observed as a change in sensitivity), and the accuracy with which the (exponential) calibration function yields exposure values as a function of digital pixel values. The calibration was performed over the exposure range from 5.1 X 10(-9) to 2.0 X 10(-5) C/kg (0.02-75 mR). The accuracy of exposure measurements made with a single imaging plate is between 1.6% and 4.2%. If measurements from several plates are involved, the uncertainty in the final measurement will be between 5% and 5.9%.

Evaluation Studies as Topic↗
PubMed1999

Use and limitations of modular metabolic control analysis in medicine and biotechnology.

By Metabolic Control Analysis (MCA), it has been shown that control on flux is in most cases shared by several enzymes rather than concentrated on one "rate-limiting step." This analysis also allows the quantification of the control exerted by groups (modules) of enzymes. The modules may correspond to spatial compartments or to functional units. A brief outline of the modular approach to MCA is given. The criteria by which the system can be modularized and the concept of monofunctional unit are explained. Various studies in which control analysis was applied to biotechnological and medical issues are reviewed. In particular, MCA has turned out to be helpful in the assessment of the severity of enzyme deficiencies. Another application is the search for target enzymes or enzyme groups where pharmaceuticals can suppress the metabolism of pathogenic microorganisms most. In biotechnology, modular and "traditional" control analyses are valuable tools for choosing the most promising targets for genetic manipulation so as to increase a biosynthetic flux. As control coefficients are linear approximations, the effect of enhancing the activities of enzymes to a larger extent is often overestimated. Further limitations such as the restriction to stationary states, uncertainties due to spatial heterogeneities and the impact of experimental error are discussed.

Animals↗
PubMed2002

Clinical trials, immunosuppression and renal transplantation: new trends in design and analysis.

Clinical trials provide a framework to search for more effective and less toxic immunosuppressive agents to control renal transplant rejection. Some methodological aspects are presented. Patient selection and the choice of study endpoints are discussed with emphasis on standardized definitions and classification of histopathology, and on qualification and quantification of chronic rejection. Choosing a Bayesian or a frequentist approach and the afferent hypotheses is discussed together with the interpretation of a P-value and a confidence interval. Strategies for limiting the number of patients, increasing power and feasibility are reviewed, including discussion of surrogate endpoints. New approaches to statistical analysis are then presented, including intention-to-treat versus per-protocol analysis, analysis of correlated data, dependent censoring, and meta-analysis applied to renal transplantation. Pharmacoeconomics are finally introduced as necessary for implementation of decision making regarding therapeutic strategies. Reporting research increases its standards, and the CONSORT (Consolidated Standards of Reporting Trials) and QOROM (Quality of Reporting of Meta-analyses) criteria are to be integrated in the process of clinical trial procedures. In conclusion, observational studies are presented as part of an evidence-based approach in the hierarchy of evidence, keeping in mind that high quality, randomized, controlled trials are still necessary to decrease uncertainty in the field of renal transplantation.

Child↗
PubMed1987

Fluorometric quantification of low-dose fluorescein delivery to predict amputation site healing.

This retrospective study evaluated quantification of skin fluorescein delivery by fiberoptic fluorometry as a means of predicting the healing potential of an amputation site. Fluorometry uses a dual-channel fiberoptic light guide--one channel transmits blue light to excite the fluorescein in the skin under study, and the other transmits emitted fluorescence from the skin to a photomultiplier tube where it is measured. Ten minutes after intravenous administration of sodium fluorescein (4 to 8 mg/kg), fluorometric readings were obtained at more than 100 reading sites. In the 86 cases without preoperative cellulitis at the site of amputation, preoperative fluorometry clearly distinguished between healing and nonhealing sites. Healing sites averaged 79% of the fluorescence of a healthy reference area (dye fluorescence index [DFI] = 79), while failing sites averaged only 27% (p less than 0.01 by ANOVA). In all but one case where the DFI was greater than 42, the amputation healed. In all cases where the DFI was less than 38, the amputation failed. In general, uncertainty was limited to sites with values between these limits. The technique maintained its high accuracy in patients with diabetes and for distal amputations. However, it was not accurate at sites of active cellulitis (12 cases). There were no significant adverse effects from the slow injection of the low dose of fluorescein used for this technique. We conclude that fluorometry is an effective means of predicting healing in patients undergoing amputation.

Amputation, Surgical↗
PubMed1996

Quantitation of benzodiazepine receptors in human brain using the partial saturation method.

UNLABELLED: The in vivo quantification of the benzodiazepine receptor concentration in humans using PET and flumazenil (FMZ) is usually based on Scatchard analysis when the goal is to avoid blood sampling. The experimental protocols, however, include several (at least two) experiments with various specific activities in the same subject to obtain a range of bound ligand concentrations. METHODS: We propose the partial saturation method, which is based on a natural decrease in bound ligand concentration after an FMZ injection with an average dose between a tracer dose and a saturation dose. An adequate range of bound ligand concentrations can thus be obtained from a single experiment. The free ligand concentration is estimated from the PET measurement in the pons after correction for the effect of the small receptor site concentration in this reference region. RESULTS: The receptor concentration and affinity estimates obtained with this approach in six regions of interest agree with previously published values obtained by using more complex approaches. Receptor concentration appears to be insensitive to the uncertainties with regard to the receptor site concentration in the pons. CONCLUSION: The partial saturation protocol can be used to estimate both the benzodiazepine receptor concentration and the FMZ affinity in routine examinations in adults (or even in children) using a single 40-min experiment without blood sampling.

Adult↗