Distinguishing Petroleum (Crude Oil and Fuel) From Smoke Exposure within Populations Based on the Relative Blood Levels of Benzene, Toluene, Ethylbenzene, and Xylenes (BTEX), Styrene and 2,5-Dimethylfuran by Pattern Recognition Using Artificial Neural Networks.

Studies of exposure to petroleum (crude oil/fuel) often involve monitoring benzene, toluene, ethylbenzene, xylenes (BTEX), and styrene (BTEXS) because of their toxicity and gas-phase prevalence, where exposure is typically by inhalation. However, BTEXS levels in the general U.S. population are primarily from exposure to tobacco smoke, where smokers have blood levels on average up to eight times higher than nonsmokers. This work describes a method using partition theory and artificial neural network (ANN) pattern recognition to classify exposure source based on relative BTEXS and 2,5-dimethylfuran blood levels. A method using surrogate signatures to train the ANN was validated by comparing blood levels among cigarette smokers from the National Health and Nutrition Examination Survey (NHANES) with BTEXS and 2,5-dimethylfuran signatures derived from the smoke of machine-smoked cigarettes. Classification agreement for an ANN model trained with relative VOC levels was up to 99.8% for nonsmokers and 100.0% for smokers. As such, because there is limited blood level data on individuals exposed to crude oil/fuel, only surrogate signatures derived from crude oil and fuel were used for training the ANN. For the 2007-2008 NHANES data, the ANN model assigned 7 out of 1998 specimens (0.35%) and for the 2013-2014 NHANES data 12 out of 2906 specimens (0.41%) to the crude oil/fuel signature category.

Amebic meningoencephalitis caused by Balamuthia mandrillaris.

Free-living amebae etiologically associated with central nervous system (CNS) infection in children have included Acanthamoeba, Naegleria, and recently, leptomyxid ameba. Two previously healthy children are reported with CNS infection caused by leptomyxid ameba, recently classified as Balamuthia mandrillaris. One child, a 27-month-old boy, had right hemiparesis and aphasia, and the other, a 13-year-old girl, had headache, right hemiparesis, diplopia, and left facial weakness. Cerebrospinal fluid studies of both children revealed a mononuclear pleocytosis and mildly elevated protein. The younger child developed seizures and progressive cerebrovascular occlusions; both developed hydrocephalus and coma progressing to death 16 days after onset of symptoms. The younger child at autopsy had necrotizing meningoencephalitis, left internal carotid arteritis, and amebic trophozoites and cysts in brain. Perivascular trophozoites were difficult to distinguish morphologically from macrophages in the older child, who had no cyst forms. Indirect immunofluorescence test revealed CNS infection with B. mandrillaris in both. This leptomyxid ameba, formerly considered an innocuous soil organism, should be considered in the differential diagnosis of progressive or atypical childhood stroke.