Neurotoxicology and Behavior

Abstract

Neurotoxicity is important to consider as a component of occupational and environmental safety and health programs. The failure to do so has contributed to a number of cases in which workers, consumers of manufactured products, and people exposed in the environment were irreparably harmed by exposure to compounds that proved toxic to the nervous system. The field of neurotoxicology originated in response to several episodes of mass poisoning and developed through advances in clinical practice, scientific research, and regulatory actions. This chapter reviews broadly the development of the field of neurotoxicity and discusses some of the predominant current issues. The chapter includes an introduction to the structure and function of the nervous system, the response to injury, the evaluation of sensory, cognitive, and motor functions, and effects on emotionality, mood, and social conduct. Recently, there has been a growing emphasis on potential toxic effects on neurodevelopment and contributions to neurodegenerative diseases. Also, there is a large and growing effort to develop more rapid and cost‐efficient screening tests for potential neurotoxicity. A brief overview of some of the major classes of neurotoxic substances is provided including metals, solvents, pesticides, and persistent organic compounds. Finally, the need for programs to prevent neurotoxic illness is discussed.

Silver Impairs Neurodevelopment: Studies in PC12 Cells

“…Each year, thousands of new chemicals are released into the environment, a substantial proportion of which are likely to elicit developmental neurotoxicity ( Boyes 2001 ), thus contributing to the “silent pandemic” of neurodevelopmental disorders ( Grandjean and Landrigan 2006 ). Recently, there has been an explosive increase in the use of silver in medical and consumer products, largely in the form of silver nanoparticles, leading to a corresponding increase in human and ecosystem exposures ( Chen and Schluesener 2008 ).…”

“…First, silver penetrates the placental barrier and accumulates in the fetus, achieving tissue concentrations of 20 ppb (0.2 μM), much higher than those in the mother, with persistence through the first postnatal year ( Lyon et al 2002 ). Second, the antimicrobial activity of Ag + relies on its abilities to inhibit DNA synthesis, degrade protein function, and evoke oxidative stress ( Feng et al 2000 ; Le Pape et al 2004 ), the same targets shared by many developmental neurotoxicants ( Boyes 2001 ; Grandjean and Landrigan 2006 ; Slotkin 2005 ; Slotkin et al 2007b ). Indeed, the developing brain may provide an environment especially conducive to silver toxicity because of its higher oxygen consumption and unique membrane lipid composition, increased metabolic demand associated with growth, lower reserves of protective enzymes and antioxidants, and low concentrations of glia, which in the adult brain protect neurons by scavenging reactive oxidative species ( Gupta 2004 ; Tanaka et al 1999 ).…”

From solidarity to division: An analysis of Lech Wałęsa's transition to constituted leadership

“…5 Walesa's biography shares characteristics that leadership scholars have noted are unusually common among leaders: the loss of one's father at an early age and contrasting relationships with two parents, in which the future leader had a positive relationship with one parent and a negative one with the other. In offering an explanation of the correlation between loss of father and future leadership, Howard Gardner posits that children who have lost a parent are stimulated to formulate their own practices in social and moral domains, and that this self-dependence "may 8 place them in a favorable opinion for directing the behavior of others." 6 Similarly, Gardner suggests that contrasting relationships with different parents fosters feelings of ambivalence, and that "the impulse to wield power represents an attempt to resolve this anxiety-producing conflict."…”

“…7 Roger Boyes noted the impact of this dynamic on Walesa: "His brittle relationship with his stepfather had two clear effects: it gave him an ambiguous relationship to authority, part rebel, part conformist." 8 Life in the Polish countryside was bleak with limited opportunities for social advancement. In addition to working on the family farm, Walesa attended classes at the village school and mass at the local Catholic parish.…”