Biokinetics of inhaled radioactive methane in rats: A pilot study

Carlisle, Sara M.; Burchart, P.; McCauley, Candace; Surette, R.A.

doi:10.1016/j.apradiso.2005.01.010

Cited by 15 publications

(15 citation statements)

References 9 publications

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“…The animals were the same strain as those used in the previous methane dosimetry studies (Carlisle et al 2004(Carlisle et al , 2005. The rats were acclimatized for a minimum of one week after receipt.…”

Section: Animal Exposuresmentioning

confidence: 99%

“…Due to the long half-life of 14 C (5,730 y), decay correction of the 14 C data was not required (Carlisle et al 2005). To allow for comparison of data despite varied exposure conditions, all decay-corrected sample data were normalized to the estimated inhaled activity from the pilot study and averaged after decay correction as shown in eqn (2) (pilot study decay-corrected exposure estimates: 220 MBq inhaled 3 H, 46 MBq inhaled 14 C).…”

Section: Animal Exposuresmentioning

confidence: 99%

“…Animals were randomly assigned to treatment groups or added to treatment groups from the previous dual-label study to increase the number of animals in these groups (Carlisle et al 2005). A total of nine treatment groups were used (Table 1).…”

Section: Animal Exposuresmentioning

confidence: 99%

“…This was not in accordance with the ICRP 3 H-methane model assumption, that 3 H becomes uniformly distributed throughout the body. As a result, a second study (pilot study) was performed to determine the possibility of simultaneously measuring 3 H and 14 C in tissues from rats exposed to mixed 3 H-and 14 C-methane (Carlisle et al 2005). Rats were examined at 1 h and 1 d after inhalation of mixed 3 H-and 14 Cmethane.…”

mentioning

confidence: 99%

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Retention and Excretion of Inhaled 3H and 14C Radiolabeled Methane in Rats

Didychuk

Burchart²,

Carlisle³

et al. 2014

Health Physics

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A radiological concern for workers at heavy water reactor nuclear facilities is the hazard presented by tritium (H) and C. Radioactive methane is one of many potential H and C containing chemicals to which Nuclear Energy Workers (NEWs) may be exposed. Current dosimetric models for H- and C-methane, recommended by the International Commission on Radiological Protection (ICRP), are based on the assumption that 1% of methane is absorbed following its inhalation. Of this 1%, all H is converted immediately to tritiated water and C is converted immediately to CO2 (50%) and organically bound carbon (50%). In the study, rats were exposed to methane standards (H-methane and C-methane) mixed with breathing air to give a final concentration of 0.27% methane and resulting in final activity concentrations of 4.2 GBq m and 0.88 GBq m for H and C, respectively. This corresponds to exposure estimates of 580 kBq g and 120 kBq g. Simultaneous exposure to H- and C-methane allowed for the direct comparison of the retention of these radionuclides and removed uncertainties concerning their relative uptake and retention. The results demonstrate that the total methane uptake from the inhaled dose was threefold less than the 1% methane uptake predicted by the ICRP dosimetric models for H- and C-methane, with the H concentration being substantially higher than anticipated in the liver. This study provided data suggesting that current ICRP dosimetric methane models overestimate the fraction of H- and C-methane that is absorbed following inhalation and assisted in providing information to better understand the metabolism of inhaled H and C radiolabeled methane.

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Section: Animal Exposuresmentioning

confidence: 99%

Section: Animal Exposuresmentioning

confidence: 99%

Section: Animal Exposuresmentioning

confidence: 99%

mentioning

confidence: 99%

See 2 more Smart Citations

Retention and Excretion of Inhaled 3H and 14C Radiolabeled Methane in Rats

Didychuk

Burchart²,

Carlisle³

et al. 2014

Health Physics

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show abstract

“…During ischemia, the mitochondrial NADH/NAD + and FADH/FAD + ratios remain elevated, leading to reductive stress Boros 1999), while reperfusion of the previously ischemic tissue leads to oxidative stress with a burst of ROS generation following the start of reoxygenation. It was earlier suggested (without indicating the exact biochemistry, contributing compounds or enzymes) that ROS reactions could lead to a higher level of fixation of CH4 in a lipid environment, such as the mitochondrium membrane (Carlisle 2005;Dougherty 1967). Indeed, IR perturbs the heterogeneous lipidbilayer membrane structure and changes the fluidity from fluid to gel.…”

Section: Effects Of Ch4 In Mitochondrial Dysfunctionmentioning

confidence: 99%