title: Editor's Highlight: Lower Fractional Anisotropy in the Globus Pallidus of Asymptomatic Welders, a Marker for Long-Term Welding Exposure.
abstract: Welding fumes contain several metals including manganese (Mn), iron (Fe), and copper (Cu) that at high exposure may co-influence welding-related neurotoxicity. The relationship between brain accumulation of these metals and neuropathology, especially in welders with subclinical exposure levels, is unclear. This study examined the microstructural integrity of basal ganglia (BG) regions in asymptomatic welders using diffusion tensor imaging (DTI).
  
  
  
  Subjects with (n = 43) and without (age- and gender-matched controls; n = 31) history of welding were studied. Occupational questionnaires estimated short-term (HrsW; welding hours and E90; cumulative exposure, past 90 days) and long-term (YrsW; total years welding and ELT; cumulative exposure, lifetime) exposure. Whole blood metal levels (Mn, Fe, and Cu) were obtained. Brain MRI pallidal index (PI), R1 (1/T1), and R2* (1/T2*) were measured to estimate Mn and Fe accumulation in BG [caudate, putamen, and globus pallidus (GP)]. DTI was used to assess BG microstructural differences, and related with exposure measurements.
  
  
  
  When compared with controls, welders had significantly lower fractional anisotropy (FA) in the GP. In welders, GP FA values showed non-linear relationships to YrsW, blood Mn, and PI. GP FA decreased after a critical level of YrsW or Mn was reached, whereas it decreased with increasing PI values until plateauing at the highest PI values. GP FA, however, did not show any relationship with short-term exposure measurements (HrsW, E90), blood Cu and Fe, or R(2)* values.
  
  
  
  GP FA captured microstructural changes associated with chronic low-level Mn exposure, and may serve as a biomarker for neurotoxicity in asymptomatic welders.
authors.affiliation: *Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033;
authors.forename: Eun-Young
authors.initials: EY
authors.lastname: Lee
authors.affiliation: Department of Environmental Sciences and Engineering, University of North Carolina, Chapel Hill, North Carolina 27599;
authors.forename: Michael R
authors.initials: MR
authors.lastname: Flynn
authors.affiliation: *Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033;
authors.forename: Guangwei
authors.initials: G
authors.lastname: Du
authors.affiliation: *Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033; Department of Pharmacology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033;
authors.forename: Mechelle M
authors.initials: MM
authors.lastname: Lewis
authors.affiliation: Department of Biostatistics, University of North Carolina, Chapel Hill, North Carolina 27599;
authors.forename: Amy H
authors.initials: AH
authors.lastname: Herring
authors.affiliation: Department of Biostatistics, University of North Carolina, Chapel Hill, North Carolina 27599;
authors.forename: Eric
authors.initials: E
authors.lastname: Van Buren
authors.affiliation: Department of Biostatistics, University of North Carolina, Chapel Hill, North Carolina 27599;
authors.forename: Scott
authors.initials: S
authors.lastname: Van Buren
authors.affiliation: Department of Public Health Sciences;
authors.forename: Lan
authors.initials: L
authors.lastname: Kong
authors.affiliation: *Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033; Department of Pharmacology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033;
authors.forename: Richard B
authors.initials: RB
authors.lastname: Mailman
authors.affiliation: *Department of Neurology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033; Department of Pharmacology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033; Department of Radiology; Department of Neurosurgery; Department of Kinesiology, Pennsylvania State University-Milton S. Hershey Medical Center, Hershey, Pennsylvania 17033 Xuemei@psu.edu.
authors.forename: Xuemei
authors.initials: X
authors.lastname: Huang
mesh_terms: D000328:Adult; D016880:Anisotropy; D005917:Globus Pallidus / Q000000981:diagnostic imaging*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008670:Metals / Q000097:blood; D008875:Middle Aged; D016273:Occupational Exposure; D011795:Surveys and Questionnaires; D014896:Welding
chemical_list: D008670:Metals
keywords: diffusion tensor imaging; fractional anisotropy; globus pallidus; manganese.; pallidal index; welders