کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9034579 | 1562442 | 2005 | 11 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Concentration-dependence of aniline-induced methemoglobinemia in dogs: A derivation of an acute reference concentration
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کلمات کلیدی
موضوعات مرتبط
علوم زیستی و بیوفناوری
علوم محیط زیست
بهداشت، سم شناسی و جهش زایی
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چکیده انگلیسی
Four male Beagle dogs per group were head-only exposed to aniline vapor in concentrations ranging from 15.8 to 493.6 mg/m3. Each exposure session was for 4 h. Additionally, one group of dogs was both head-only and whole-body exposed to approximately 241 mg/m3 to better appreciate the contribution of dermal uptake on methemoglobin (MetHb) induction. The exposure paradigm chosen was comparable to a dose-escalation type of study, however, providing adequate recovery periods between each exposure session to exclude 'carry-over' effects from one exposure session to another. This was verified by the determination of standard hematology endpoints before and after each exposure session. The time- and concentration-dependence of MetHb was analyzed as the key endpoint. The results of this study show that MetHb was maximal around the end of the 4 h exposure period. Significantly increased MetHb was observed at concentrations equal and above 30.3 mg/m3 at a duration of exposure of at least 60 min. The extent of MetHb formation observed in some hyperventilating dogs suggests that the dosing-rate is important for the outcome of test. Whole body exposed dogs displayed markedly higher MetHb values when compared to head-only exposed dogs. Taking into account the entire concentration-time-effect relationship 23.6 and 20.6 mg/m3 were estimated to be the threshold concentrations to cause 0.8% MetHb following a 4 and 8 h exposure period, respectively. The Cn Ã t analysis of MetHb formation is consistent with a concentration-dependent restoration kinetics of MetHb suggesting that results from high level exposures cannot readily be extrapolated to low-level exposures. In summary, this study demonstrates that for aniline, an agent known to be bioactivated by a hepatic first-pass metabolism, the rate of delivery and uptake appears to be decisive for the extent of MetHb formation. Carry-over effects related to erythrotoxicity or Heinz body formation were not observed at any exposure level.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Toxicology - Volume 214, Issues 1â2, 15 October 2005, Pages 140-150
Journal: Toxicology - Volume 214, Issues 1â2, 15 October 2005, Pages 140-150
نویسندگان
Jürgen Pauluhn,