Regulatory toxicology and pharmacology : RTP
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Regul. Toxicol. Pharmacol. · Nov 2005
Comparative StudyHumans appear no more sensitive than laboratory animals to the inhibition of red blood cell cholinesterase by dichlorvos.
Inhibition of red blood cell (RBC) cholinesterase is a consistent and sensitive indicator of exposure to dichlorvos (DDVP). Absent human data, default 10-fold adjustment factors for potential interspecies and intraspecies sensitivity differences would be used in developing a reference dose from the no observed effect levels for this endpoint obtained in toxicological assessments of laboratory animals. ⋯ In aggregate, these data demonstrate that the DDVP doses producing inhibition in humans are virtually identical to those eliciting the same levels of inhibition in laboratory rats, mice, monkeys, and dogs. Thus, healthy humans appear to be no more sensitive than laboratory animals to DDVP's effects on RBC cholinesterase, and an interspecies uncertainty factor of 1 is appropriate and scientifically warranted for use in DDVP risk assessments.
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Regul. Toxicol. Pharmacol. · Apr 2005
Smoke composition and predicting relationships for international commercial cigarettes smoked with three machine-smoking conditions.
The study objectives were to determine the effects of smoking machine puffing parameters on mainstream smoke composition and to express those effects as predicting relationships. Forty-eight commercial Philip Morris USA and Philip Morris International cigarettes from international markets and the 1R4F reference cigarette were machine-smoked using smoking conditions defined by the International Organization of Standardization (ISO), the Massachusetts Department of Public Health (MDPH), and Health Canada (HC). Cigarette tobacco fillers were analyzed for nitrate, nicotine, tobacco-specific nitrosamines (TSNA), and ammonia. ⋯ MDPH and HC constituent yields could be predicted with similar reliability using ISO tar or the corresponding smoking-condition tar. The reliability of the relationships varied from strong to weak, depending on particular constituents. Weak predicting relationships for nitrogen oxides and TSNA's, for example, were improved with inclusion of tobacco filler composition factors. "Smoke pH" was similar for all cigarettes at any one smoking condition, and overall marginally lower at HC conditions than at ISO or MDPH conditions.
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Regul. Toxicol. Pharmacol. · Dec 2004
Subacute toxicity evaluation of a new camptothecin anticancer agent CKD-602 administered by intravenous injection to rats.
The subacute toxicity of a new camptothecin anticancer agent, CKD-602, was investigated after 4-week repeated intravenous administration of the chemical in Sprague-Dawley rats. The test chemical was administered intravenously to rats at dose levels of 0, 0.003, 0.013, or 0.067 mg/kg/day for males and 0, 0.004, 0.018, or 0.089 mg/kg/day for females. At the end of the treatment period, 10 rats/sex/group were sacrificed. ⋯ There were no adverse effects in the low and middle dose groups of both genders. In the present experimental conditions, the target organs were determined to be bone marrow, blood cells, spleen, liver, thymus, and heart. The no-observed-adverse-effect level was considered to be 0.013 mg/kg/day for males and 0.018 mg/kg/day for females.
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Regul. Toxicol. Pharmacol. · Oct 2004
Risk assessment of oral exposure to diisononyl phthalate from children's products.
Dialkyl phthalates are plasticizers used in household products made from polyvinyl chloride (PVC). Diisononyl phthalate (DINP) is the principal phthalate in soft plastic toys. Because DINP is not tightly bound to PVC, it may be released when children mouth PVC products. ⋯ S. Consumer Product Safety Commission. Because this material was prepared by the authors in their official capacity, it is in the public domain and may be freely copied or reprinted.