Maximum likelihood analysis of bioassay data from long-term follow-up of two refractory PuO2 inhalation cases.
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Cites background or result from "Maximum likelihood analysis of bioa..."
...The distributions of parameter values estimated in the current analysis are consistent with those reported in other human studies (Gregoratto et al., 2010, 2011; Avtandilashvili et al., 2012), and as such would be expected to provide similar estimates of the long-term retained lung burden at similar exposure conditions....
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...This model structure has been shown to improve the estimates of the long-term retained lung burdens of poorlysoluble particles in humans, including those with relatively low inhaled particle exposures (Gregoratto et al., 2010, 2011; Avtandilashvili et al., 2012)....
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...…of parameter values estimated in the current analysis are consistent with those reported in other human studies (Gregoratto et al., 2010, 2011; Avtandilashvili et al., 2012), and as such would be expected to provide similar estimates of the long-term retained lung burden at similar exposure…...
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7 citations
Cites methods from "Maximum likelihood analysis of bioa..."
...The faecal bioassay data points were not used in modelling because the masses of the faecal voids were unknown (Avtandilashvili et al 2012)....
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...The individual received 1 g of Ca-DTPA each day from the day of intake to day 4, but the treatments did not significantly increase the plutonium excretion in urine as evident in the urine measurements (Mann and Kirchner 1967, Avtandilashvili et al 2012)....
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...In addition, the intake calculated here also compares well with the values of between 7.3 × 104 Bq and 1.3 × 105 Bq calculated by Avtandilashvili et al (2012) using maximum likelihood analysis and different absorption and particle transport models....
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...The values of dissolution parameters estimated in this study agree well with those estimated by Avtandilashvili et al (2012) for the individual (f r = 0.004, ss = 5 × 10–6 d−1), and those estimated by Gregoratto et al (2010) for the cohort involved in the same fire (f r = 0.005, ss = 4 × 10–6 d−1) ....
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...The detailed methodology is described in Avtandilashvili et al (2012)....
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References
123 citations
"Maximum likelihood analysis of bioa..." refers methods in this paper
...As a final step, the Leggett et al. (2005) model of plutonium systemic biokinetics was coupled with the ‘‘optimized’’ Gregoratto et al. (2010) (OGPT) particle transport model in order to examine the effect of the systemic model on the fit and the predicted tissue doses....
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...For plutonium systemic biokinetics, ICRP 67 model (ICRP 1993) and Leggett et al. (2005) model were used....
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106 citations
"Maximum likelihood analysis of bioa..." refers methods in this paper
...Data analysis method IMBA Professional Plus\ (IPP) software (Birchall et al. 2007) was used for bioassay data analysis and assessment of the intake and doses....
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...IMBA Professional Plus\ (IPP) software (Birchall et al. 2007) was used for bioassay data analysis and assessment of the intake and doses....
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...Data analysis method IMBA Professional Plus\ (IPP) software (Birchall et al. 2007) was used for bioassay data analysis and assessment of the intake and doses. This code allows a user to calculate bioassay quantities and doses from a known intake as well as, in reverse, to estimate the best intake from a set of up to 200 bioassay measurements. To derive the ‘‘best fit’’ to the measurement data, the user is given the option to apply the maximum likelihood method or use Bayesian inference. The maximum likelihood method as implemented in IPP enables the user to handle the measurement data that are below some defined limit of detection (LOD) in an unbiased manner. Data recorded as ‘‘GLOD’’ are used in calculations by accounting for the probability that the true value is between zero and LOD. This probability is estimated as an area under the error distribution of the measurement. The ability of the IMBA maximum likelihood fitting algorithm to obtain an unbiased estimate of intake in the case of ‘‘GLOD’’ data was demonstrated by Marsh et al. (2003) using Monte Carlo simulations....
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69 citations
"Maximum likelihood analysis of bioa..." refers background or methods in this paper
...Implementation of the Gregoratto et al. (2010) particle transport (GPT) model using the same custom-fitted absorption parameters and ICRP 67 plutonium systemic 75Analysis of bioassay data from refractory PuO2 inhalation cases c M. AVTANDILASHVILI ET AL. www.health-physics.com Copyright © 2012…...
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...To account for the observed long-term retention of insoluble material in the lungs, Gregoratto et al. (2010) proposed a physiologically-based particle transport model that significantly simplifies the representation of particle clearance from the alveolar-interstitial (AI) region by *Department of…...
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...The simplified particle transport model derived byGregoratto et al. (2010). All rate constants are in d....
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...It is notable that the ‘‘optimized’’ Gregoratto et al. (2010) model provides more credible overall fit to the bioassay data (including the lung retention data) for both cases, together with the Case 0202 liver and skeletal content of 239,240Pu determined from the autopsy....
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...Hence, this evaluation supports the Gregoratto et al. (2010) proposed revision to the ICRP 66 model when considering situations of extremely insoluble particles. The slow clearance of deposited particles from the lungs as observed in these cases is not consistent with the default ICRP HRTM representation of clearance from the alveolar-interstitial region, which describes a faster clearing pathway than experienced with these small, very insoluble particles. As a final step, the Leggett et al. (2005) model of plutonium systemic biokinetics was coupled with the ‘‘optimized’’ Gregoratto et al. (2010) (OGPT) particle transport model in order to examine the effect of the systemic model on the fit and the predicted tissue doses....
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34 citations
"Maximum likelihood analysis of bioa..." refers methods in this paper
...The corresponding geometric standard deviations (GSD) were assigned on a basis of the values determined by Marsh et al. (2007) for monitoring bioassay data....
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33 citations
"Maximum likelihood analysis of bioa..." refers methods in this paper
...Coupled with the proposed elimination of the HRTM’s ‘‘slowly-cleared’’ fraction of particles passing through the bronchioles and bronchi (Falk et al. 1999), the new AI clearance model proposed by Gregoratto et al. (Fig....
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...Coupled with the proposed elimination of the HRTM’s ‘‘slowly-cleared’’ fraction of particles passing through the bronchioles and bronchi (Falk et al. 1999), the new AI clearance model proposed by Gregoratto et al....
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