Thus, modeling techniques need to be adapted to children in order to estimate inhaled dose and risk in this potentially susceptible life stage. This paper summarizes a series of inhalation dosimetry presentations from the U.S. EPA’s Workshop on Inhalation Risk Assessment in Children held on June 8-9, 2006 in Washington, DC. These presentations demonstrate how existing default Daporinad supplier models for particles and gases may be adapted for children,

and how more advanced modeling of toxicant deposition and interaction in respiratory airways takes into account children’s anatomy and physiology. These modeling efforts identify child-adult dosimetry differences in respiratory tract regions that may have implications for children’s vulnerability to inhaled toxicants. A decision framework is discussed that considers these different approaches and modeling structures including assessment of parameter values, supporting data, reliability, and selection of dose metrics.”
“Adults and children selleck kinase inhibitor may have different reactions to

inhalation exposures due to differences in target tissue doses following similar exposures, and/or different stages in lung growth and development. In the case of asthma and allergy both the developing immune system and initial encounters with common allergens contribute to this differential susceptibility. Asthma, the most common chronic childhood disease, has significant public health impacts and is characterized by chronic lung inflammation, reversible airflow obstruction, and immune sensitization to allergens. Animal studies described here suggest that air pollutants exacerbate asthma symptoms and may also play a role in disease induction. Changes characteristic of asthma were observed in rhesus monkeys sensitized to house dust mite antigen (HDMA) as infants and exposed repeatedly thereafter to ozone (O-3) and HDMA. O-3 exposure compromised airway growth and development

and exacerbated the allergen response to favor intermittent airway obstruction and wheeze. In Brown Norway rats a variety of air pollutants see more enhanced sensitization to HDMA such that symptoms elicited in response to subsequent allergen challenge were more severe. Although useful for assessing air pollutants effects on initial sensitization, the rodent immune system is immature at birth relative to humans, making this model less useful for studying differential effects between adults and children. Because computational models available to address children’s inhalation exposures are limited, default adjustments and their associated uncertainty will continue to be used in children’s inhalation risk assessment. Because asthma is a complex (multiple genes, phenotypes, organ systems) disease, this area is ripe for systems biology approaches.”
“The U.S.