We have two major lines of investigation. The first focus is on the health effects of particulates on cardiovascular disease. With a grant from USEPA's STAR program we are presently investigating the impact of fine and ultrafine particulate from diesel exhaust on acute changes in platelet activation and arterial wall reactivity. These human exposure experiments are done on healthy subjects with and without a single nucleotide polymorphism that may convey increased susceptibility to particle effects. They are conducted in EOHSI's Controlled Exposure Facility, of which I am also medical director. The ultimate goal of this work is to elucidate a mechanism to explain the substantial increases in acute cardiac illness that are seen when fine and ultrafine particle levels increase in the ambient atmosphere.

The second line of investigation involves exploring the interactions between environmental exposures and stress and individual susceptibility to explain health outcomes such as symptomatic illness, asthma, and disability. This is explored in epidemiologic models in cohorts such as the 1990-1991 Gulf War veterans and New York City firefighters who were present at the collapse of the World Trade Center. These interactions are also explored in human controlled exposure studies to low concentrations of a variety of toxic agents such as a mixture of volatile organics with and without ozone, hydrogen sulfide, and diesel exhaust. Funding for these experiments comes from NIEHS, NIOSH, US DOD, and private industry.

	Responses to controlled diesel vapor exposure among chemically sensitive gulf war veterans. Fiedler N, Giardino N, Natelson B, Ottenweller JE, Weisel C, Lioy P, Lehrer P, Ohman-Strickland P, Kelly-McNeil K, Kipen H. Psychosom Med. 2004 Jul-Aug;66(4):588-98.
	Work-attributed symptom clusters (darkroom disease) among radiographers versus physiotherapists: associations between self-reported exposures and psychosocial stressors. Tarlo SM, Liss GM, Greene JM, Purdham J, McCaskell L, Kipen H, Kerr M. Am J Ind Med. 2004 Jun;45(6):513-21.
	Reported exposures, stressors, and life events among Gulf War Registry veterans. Boyd KC, Hallman WK, Wartenberg D, Fiedler N, Brewer NT, Kipen HM. J Occup Environ Med. 2003 Dec;45(12):1247-56.
	Unexplained symptoms after terrorism and war: an expert consensus statement. Clauw DJ, Engel CC Jr, Aronowitz R, Jones E, Kipen HM, Kroenke K, Ratzan S, Sharpe M, Wessely S. J Occup Environ Med. 2003 Oct;45(10):1040-8.