Intraventricular mass lesions at magnetic resonance imaging: iconographic essay - part 2.

The present essay is illustrated with magnetic resonance images obtained at the authors' institution over the past 15 years and discusses the main imaging findings of intraventricular tumor-like lesions (colloid cyst, oligodendroglioma, astroblastoma, lipoma, cavernoma) and of inflammatory/infectious lesions (neurocysticercosis and an atypical presentation of neurohistoplasmosis). Such lesions represent a subgroup of intracranial lesions with unique characteristics and some imaging patterns that may facilitate the differential diagnosis.

Intraventricular mass lesions at magnetic resonance imaging: iconographic essay - part 1.

The present essay is illustrated with magnetic resonance images obtained at the authors' institution over the past 15 years and discusses the main imaging findings of intraventricular tumor-like lesions (ependymoma, pilocytic astrocytoma, central neurocytoma, ganglioglioma, choroid plexus papilloma, primitive neuroectodermal tumors, meningioma, epidermoid tumor). Such lesions represent a subgroup of intracranial lesions with unique characteristics and some image patterns that may facilitate the differential diagnosis.

Effect of dissolved oxygen on two bacterial pathogens examined using ATR-FTIR spectroscopy, microelectrophoresis, and potentiometric titration.

The effects of dissolved oxygen tension during bacterial growth and acclimation on the cell surface properties and biochemical composition of the bacterial pathogens Escherichia coli O157:H7 and Yersinia enterocolitica are characterized. Three experimental techniques are used in an effort to understand the influence of bacterial growth and acclimation conditions on cell surface charge and the composition of the bacterial cell: (i) electrophoretic mobility measurements; (ii) potentiometric titration; and (iii) ATR-FTIR spectroscopy. Potentiometric titration data analyzed using chemical speciation software are related to measured electrophoretic mobilities at the pH of interest.

Role of oxygen tension on the transport and retention of two pathogenic bacteria in saturated porous media.

To examine the influence of variations in the dissolved oxygen (DO) concentration on pathogen mobility, laboratory-scale filtration experiments were performed using the enterohemorrhagic strain Escherichia coli O157:H7 and the enteroinvasive organism Yersinia enterocolitica. Cells were incubated either in the absence (anaerobic) or in the presence (aerobic) of oxygen to understand how these two growth conditions may affect bacterial transport and retention in water-saturated granular porous media. The influence of DO during growth is found to be organism dependent, whereby E.

Transport of selected bacterial pathogens in agricultural soil and quartz sand.

The protection of groundwater supplies from microbial contamination necessitates a solid understanding of the key factors controlling the migration and retention of pathogenic organisms through the subsurface environment. The transport behavior of five waterborne pathogens was examined using laboratory-scale columns packed with clean quartz at two solution ionic strengths (10 mM and 30 mM). Escherichia coli O157:H7 and Yersinia enterocolitica were selected as representative Gram-negative pathogens, Enterococcus faecalis was selected as a representative Gram-positive organism, and two cyanobacteria (Microcystis aeruginosa and Anabaena flos-aquae) were also studied.

Relevance of nontoxigenic strains as surrogates for Escherichia coli O157:H7 in groundwater contamination potential: role of temperature and cell acclimation time.

Nontoxigenic bacteria are commonly used as indicators for predicting the contamination potential of pathogens in natural or engineered aqueous environments. In this study, column transport experiments were used to examine the relevance of two nontoxigenic strains of Escherichia coli O157:H7 as potential surrogates for the well-known pathogen. Experiments conducted at 11 degrees C indicate that only one of the nontoxigenic strains may be an appropriate surrogate for predicting the migration potential of the pathogen at low solution ionic strengths.