Radionuclide assessment of regional left ventricular function in acute myocardial infarction

To determine changes in global and regional left ventricular function following acute myocardial function, 17 patients underwent radionuclide angiography at 3 and 10 days post infarction. Five patients had nontransmural myocardial infarction and 12 had transmural infarction (six anterior and six inferior). There were no previous infarctions in 16 (94%) patients. Regional ejection fractions were calculated by dividing the left ventricle into four quadrants using the geometric center of the left ventricle on the end-diastolic frame as a reference point. At 3 days post infarction, 8 of 17 (47%) patients had an abnormality of global left ventricular ejection fraction (LVEF), whereas 16 of 17 (94%) patients had abnormalities of one or more regional ejection fractions (p p = NS). However, there were significant changes in 23 of 68 (34%) regional LVEFs. These changes did not relate to type, ECG location, creatine kinase (CK) size of infarction, or initial global LVEF. These data suggest that regional LVEF is a sensitive technique for identifying segmental dysfunction associated with myocardial infarction. In addition, significant changes occur in regional LV function during acute myocardial infarction despite stable serial global LV performance.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26327/1/0000414.pd

Solid-phase speciation of Pb in urban road dust sediment: a XANES and EXAFS study

The quality of the urban environment is of growing concern as its human population continues to dramatically increase. X-ray absorption spectroscopy (XAS) and SEM have been used to study the solid-phase speciation of Pb in urban road dust sediments (RDS) in Manchester, UK. XANES analysis and linear combination modeling indicate that PbCrO4 and Pb-sorbed goethite occur in 1000−500 μm, 250−125 μm, 63−38 μm, and <38 μm size fractions, collectively representing between 51−67% of the contributing Pb-phases. XANES analysis suggests that PbO, PbCl2, and Pb carbonates are also present. EXAFS modeling for all grain size fractions gives best fit models with a first shell of two oxygen atoms at 2.29−2.32 Å, which corroborate the possible presence of Pb-sorbed goethite, and also suggest the presence of Pb phosphates and Pb oxides. Second shell Pb−Fe and second and third shell Pb−Pb scattering distances confirm Pb-sorbed to Fe oxide, and PbCl2 and PbCrO4, respectively. Many of the XAS models are corroborated by SEM observations. The Pb-phases may pose a risk to human health if inhaled or ingested, with insoluble phases such as PbCrO4 potentially causing inflammation in the lungs, and soluble phases such as PbO potentially being the most bioaccessible in the digestive tract