Temporal Variation in the Micro-Distribution of Enriched UO2 Particles Deposited in the Left Lung of the Rat

Morris, Keith; Barker, Chris; Batchelor, A.L.; Khanna, Paul

doi:10.1093/oxfordjournals.rpd.a081094

Cited by 2 publications

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“…The number of clusters in the central alveolar tissue region tended to reach a maximum after 360 days PI, falling slightly by 720 days PI. Morris et al (8) reported that the U02 particles appeared to clear faster from the central alveolar region than from the subpleural alveolar and ciliated airway region. Thus, fewer, particles will aIn all cases the track aggregates appeared to be due to the clustering of alveolar or interstitial macrophages.…”

Section: Resultsmentioning

confidence: 99%

“…At later times points, all the macrophage clusters were under the airway epithelium and normally associated with airway lymphatic tissue, suggesting that particles within these interstitial macrophages would be retained in this location for long periods. Morris et al (8) suggest that the observed U02 distribution pattern will lead to a significant dose to the airway tissue, similar to the accumulated dose received by the central and subpleural alveolar tissue from 4 to 720 days PI. No macrophage clusters were observed to be related to alveoli or airway perivascular tissue.…”

Section: Estimation Of Number Of Macrophage Clusters Within All Cr-39mentioning

confidence: 87%

“…While scanning some ofthe CR-39 autoradiographs to obtain data for earlier work (8), it was noticed that occasionally some large foci of 235U fission fragment tracks were seen. These track aggregates were markedly larger than the normal circular foci of tracks and were made up of many overlying large foci (see Figures 1-4).…”

Section: Estimation Of Number Of Macrophage Clusters Within Cr-39 Autmentioning

confidence: 99%

“…This was repeated for all rats, at all time points, giving a total of 52 lung autoradiographs scanned from the 4 rats killed at 1 For some ofthe left lung autoradiographs the total number of fission fragment tracks within the section was already known (8). This was true for all the autoradiographs from the eighth 3-mm slice from the left lung apex (one section per rat) and for all time points from 1 to 720 days PI (a total of24 autoradiographs).…”

Section: Estimation Of Number Of Macrophage Clusters Within Cr-39 Autmentioning

confidence: 99%

“…Earlier work with the sam sections suggested that the central alveoli, subpleura airway tissue regions would receive about the sE particle dose over the 720 days PI (8). In this pa domness ofthe U02 particle distribution in the lung vestigated to discover if the dose within these thre regions is likely to be uniform or highly uneven.…”

Section: Introductionmentioning

confidence: 97%

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Dosimetric implications of pulmonary macrophage clusters observed within lungs of rats that have inhaled enriched UO2 particles.

Morris

Barker²,

Batchelor³

et al. 1992

Environ Health Perspect

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Tlwenty-four wscher 34 rts were exposed to enriched uranium dioKide (UO0) aerosols to give a mean initial lung burden of291 ± 89 (SD) yg. Groups of rats were killed at 1, 7, 180, 360, 540, and 720 days post-inhalation (PI). Their lungs were fixed and inflated. Sections cut from all five lung lobes were used to prepare CR-39 neutron-induced 23.U fission frament autoradiographs. A single traverse across a CR-39 autoradiograph of a tissue section, from the left lung of all the rats, was made using a motorized microscopic stage. The traverse was divided into 10 fields. The track counts per field were used to test for homogeneity oftrack distribution and to assess if there was any tendency for tracks to be related to the peripheral region ofthe lung. FRUl raster scans across the entiretissue image were made on left lung autoradiographs from two animals kifled at each time point toassess the homogeneity offission fgment track dition ughout the entire section. There was no evidence of any temporal change in the proportion of tracks associated with the lung periphery. At all time points PI, the trck distribution was significantly nonhomogeneous, suggesting a nonuniform pattern of tissue irradiation from the 234U a particles.At time points from 180 to 720 days PI, large clusters of macrophages were observed in some of the sections taken from anl five lung lobes. The total number of macrophage clusters increased with time PI. These macrophage clusters produced many 235U fission fragment tracks within the CR-39 autoradiographs. The tracks within these macrophage clusters represented 04%4-4% ofthe entire trackcount for the section. The mean tU a-particle dose rate within these clusters was calculated to be 0.033 and 0.13 Gy/day, depending on the size of the cluster. This compares with the estimated dose rates averaged over the whole lung of Q021 Gy/day at 4 days PI and 0.0057 Gy/day at 720 days PI.

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Section: Resultsmentioning

confidence: 99%

Section: Estimation Of Number Of Macrophage Clusters Within All Cr-39mentioning

confidence: 87%

Section: Estimation Of Number Of Macrophage Clusters Within Cr-39 Autmentioning

confidence: 99%

Section: Estimation Of Number Of Macrophage Clusters Within Cr-39 Autmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 97%

See 3 more Smart Citations

Dosimetric implications of pulmonary macrophage clusters observed within lungs of rats that have inhaled enriched UO2 particles.

Morris

Barker²,

Batchelor³

et al. 1992

Environ Health Perspect

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Dosimetric Implications of Pulmonary Macrophage Clusters Observed within Lungs of Rats That Have Inhaled Enriched UO 2 Particles

Morris¹,

Barker²,

Batchelor³

et al. 1992

Environmental Health Perspectives

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Twenty-four Fischer 344 rats were exposed to enriched uranium dioxide (UO2) aerosols to give a mean initial lung burden of 291 +/- 89 (SD) micrograms. Groups of rats were killed at 1, 7, 180, 360, 540, and 720 days post-inhalation (PI). Their lungs were fixed and inflated. Sections cut from all five lung lobes were used to prepare CR-39 neutron-induced 235U fission fragment autoradiographs. A single traverse across a CR-39 autoradiograph of a tissue section, from the left lung of all the rats, was made using a motorized microscopic stage. The traverse was divided into 10 fields. The track counts per field were used to test for homogeneity of track distribution and to assess if there was any tendency for tracks to be related to the peripheral region of the lung. Full raster scans across the entire tissue image were made on left lung autoradiographs from two animals killed at each time point to assess the homogeneity of fission fragment track distribution throughout the entire section. There was no evidence of any temporal change in the proportion of tracks associated with the lung periphery. At all time points PI, the track distribution was significantly nonhomogeneous, suggesting a nonuniform pattern of tissue irradiation from the 234U alpha particles. At time points from 180 to 720 days PI, large clusters of macrophages were observed in some of the sections taken from all five lung lobes. The total number of macrophage clusters increased with time PI. These macrophage clusters produced many 235U fission fragment tracks within the CR-39 autoradiographs.(ABSTRACT TRUNCATED AT 250 WORDS)

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Temporal Variation in the Micro-Distribution of Enriched UO2 Particles Deposited in the Left Lung of the Rat

Cited by 2 publications

References 0 publications

Dosimetric implications of pulmonary macrophage clusters observed within lungs of rats that have inhaled enriched UO2 particles.

Dosimetric implications of pulmonary macrophage clusters observed within lungs of rats that have inhaled enriched UO2 particles.

Dosimetric Implications of Pulmonary Macrophage Clusters Observed within Lungs of Rats That Have Inhaled Enriched UO 2 Particles

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