title: Brain magnetic resonance imaging and manganese concentrations in red blood cells of smelting workers: search for biomarkers of manganese exposure.
abstract: The MRI technique has been used in diagnosis of manganism in humans and non-human primates. This cross-sectional study was designed to explore whether the pallidal signal intensity in T1-weighted MRI correlated with Mn levels in the blood compartment among Mn-exposed workers and to understand to what extent the MRI signal could reflect Mn exposure. A group of 18 randomly selected male Mn-exposed workers of which 13 were smelting workers with high exposure (mean of airborne Mn in work place: 1.26 mg/m3; range: 0.31-2.93 mg/m3), and 5 power distribution control workers with low exposure (0.66 mg/m3 and 0.23-0.77 mg/m3) from a ferroalloy factory, and another group of 9 male subjects as controls from a non-smelting factory who were office or cafeteria workers (0.01 mg/m3 and 0-0.03 mg/m3) were recruited for neurological tests, MRI examination, and analysis of Mn in whole blood (MnB), plasma (MnP) or red blood cells (MnRBC). No clinical symptoms and signs of manganism were observed among these workers. MRI data showed average increases of 7.4% (p<0.05) and 16.1% (p<0.01) in pallidal index (PI) among low- and high-exposed workers, respectively, as compared to controls. Fourteen out of 18 Mn-exposed workers (78%) had intensified PI values, while this proportion was even higher (85%) among the high Mn-exposed workers. Among exposed workers, the PI values were significantly associated with MnRBC (r=0.55, p=0.02). Our data suggest that the workers exposed to airborne Mn, but without clinical symptoms, display an exposure-related, intensified MRI signal. The MRI, as well as MnRBC, may be useful in early diagnosis of Mn exposure.
authors.affiliation: Department of Occupational Health and Toxicology, Guangxi Medical University, and Department of Radiology, The First Affiliated Hospital of Guangxi Medical University, Nanning 530021, China.
authors.forename: Yueming
authors.initials: Y
authors.lastname: Jiang
authors.forename: Wei
authors.initials: W
authors.lastname: Zheng
authors.forename: Liling
authors.initials: L
authors.lastname: Long
authors.forename: Weijia
authors.initials: W
authors.lastname: Zhao
authors.forename: Xiangrong
authors.initials: X
authors.lastname: Li
authors.forename: Xuean
authors.initials: X
authors.lastname: Mo
authors.forename: Jipei
authors.initials: J
authors.lastname: Lu
authors.forename: Xue
authors.initials: X
authors.lastname: Fu
authors.forename: Wenmei
authors.initials: W
authors.lastname: Li
authors.forename: Shouting
authors.initials: S
authors.lastname: Liu
authors.forename: Quanyong
authors.initials: Q
authors.lastname: Long
authors.forename: Jinli
authors.initials: J
authors.lastname: Huang
authors.forename: Enrico
authors.initials: E
authors.lastname: Pira
mesh_terms: D000328:Adult; D000388:Air / Q000032:analysis; D015415:Biomarkers; D001772:Blood Cell Count; D001921:Brain / Q000473:pathology*; D003430:Cross-Sectional Studies; D004912:Erythrocytes / Q000737:chemistry*; D005917:Globus Pallidus / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008345:Manganese / Q000097:blood*; D008669:Metallurgy; D008875:Middle Aged; D016273:Occupational Exposure / Q000009:adverse effects*
chemical_list: D015415:Biomarkers; D008345:Manganese