Which pathologic staining method can visualize the hyperacute infarction lesion identified by diffusion MRI?: A comparative experimental study.

BACKGROUND: The study aimed to establish a staining method that could delineate the macroscopic lesion boundary of a hyperacute infarction depicted by diffusion-weighted MRI (DWI) and to validate the infarction boundary by comparing different staining methods. NEW METHOD: Thirteen rats with 1 -h middle cerebral artery (MCA) infarction were included. Five different staining methods (Hematoxylin and eosin (H&E), Nissl, 2,3,5-triphenyltetrazolium hydrochloride (TTC), microtubule associated protein 2 (MAP2), and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) stains) were used to identify whether the hyperacute infarction could be histopathologically identified. Dice indices were compared to evaluate similarities in the lesion area ascertained by DWI and the staining methods. Through macroscopic lesion delineation, each region was subdivided into abnormal regions in all three stains (ROIA), abnormal in two stains (ROIB), and abnormal in only one (ROIC). Microscopic cellular changes were evaluated and graded according to each region. RESULTS: Mean Dice indices of the H&E stain were significantly higher than those of the Nissl- and MAP2-stained specimens (0.83 ±â€¯0.052, 0.58 ±â€¯0.107, and 0.56 ±â€¯0.059, respectively; p = 0.000). Grading scores for ROIs in the DWI abnormal lesions varied by region: ROIA exhibited the most severe damage [median (IQR), 3 (1)], followed respectively by ROIB [median (IQR), 2 (0)] and ROIC [median (IQR), 1 (0)] COMPARISON WITH EXISTING METHODS: H&E stain best reflects 1 h hyperacute DWI abnormal lesions. CONCLUSIONS: H&E stain allowed for the macroscopic delineation of the 1 h DWI-abnormal lesions, while MAP2 and Nissl stains could only partially depict lesions.

Concentration characteristics of atmospheric PCBs for urban and rural area, Korea.

Mean concentrations of total PCBs (gas+particle) detected in urban and rural atmospheres were 130.41+/-62.57 pg/m(3) and 39.65+/-34.04 pg/m(3), respectively. The concentration distribution of PCB homologs in the urban and rural area decreased with increasing Cl substitutions and showed significant correlation coefficients (P>0.05) with the octanol-air partition coefficient (K(OA)) and vapor pressure, respectively. The fractions (%) of total PCBs were 28% for tri-CBs, 25% for tetra-CBs and 24% for penta-CBs in urban air and 45% for tri-CBs, 24% for tetra-CBs, and 21% for penta-CBs in rural air. The sum of those homologs was 77% for urban and 90% for rural air. Therefore, these homologs were identified as the main components of PCB homologs compared to other homologs (>penta-CBs). The Clausius-Clapeyron (CC) plot was applied to atmospheric PCB data, relating PCB partial vapor pressure (logarithm P) to inverse absolute temperature (1/T). The slopes obtained from Clausius-Clapeyron plots were -3888 (R(2)=0.75, P<0.0001) for urban and -1902 (R(2)=0.22, P<0.1) for rural air. The slope for urban air was approximately two times higher than that of rural air, possibly because the atmospheric concentration of lower molecular weight congeners in urban air may be predominantly influenced by local sources relative to rural air.