RESUMEN
Transport of coal by train through residential neighborhoods in Metro Vancouver, British Columbia, Canada may increase the possibility of exposure to particulate matter at different size ranges, with concomitant potential negative health impacts. This pilot study identifies and quantifies train impacts on particulate matter (PM) concentrations at a single location. Field work was conducted during August and September 2014, with the attributes of a subset of passing trains confirmed visually, and the majority of passages identified with audio data. In addition to fixed ground based monitors at distances 15 and 50 m from the train tracks, an horizontally pointing mini-micropulse lidar system was deployed on three days to make backscatter and depolarization measurements in an attempt to identify the zone of influence, and sources, of train-generated PM. Ancillary wind and dust fall data were also utilized. Trains carrying coal are associated with a 5.3 (54%), 4.1 (33%), and 2.6 (17%) µgm-3 average increase in concentration over a 14 min period compared to the average concentrations over the 10 min prior to and after a train passage ("control" or "background" conditions), for PM3, PM10, and PM20, respectively. In addition, for PM10 and PM20, concentrations during train passages of non-coal-carrying trains were not found to be significantly different from PM concentrations during control conditions. Presence of coal dust particles at the site was confirmed by dust fall measurements. Although enhancements of PM concentrations during 14 min train passages were generally modest, passing coal trains occasionally enhanced concentrations at 50 m from the tracks by â¼100 µgm-3. Results showed that not every train passage increased PM concentrations, and the effect appears to be highly dependent on wind direction, local meteorology and load related factors. LiDAR imagery suggests that re-mobilization of track-side PM by train-induced turbulence may be a significant contributor to coarse particle enhancements.
Asunto(s)
Contaminantes Atmosféricos/análisis , Carbón Mineral/análisis , Polvo/análisis , Monitoreo del Ambiente , Material Particulado/análisis , Vías Férreas , Colombia Británica , Tamaño de la Partícula , Proyectos Piloto , VientoRESUMEN
A Japanese girl aged 5 years 4 months developed macroscopic hematuria and acute renal failure (ARF) 8 days before the appearance of purpura rash. A renal biopsy undertaken during the acute phase of illness revealed many red blood cells in the tubular lumina with no apparent glomerular lesions. ARF showed improvement without dialysis therapy. A second renal biopsy was performed 2.5 months later because of the prolonged proteinuria and hematuria. Sclerotic change and crescent formation were demonstrated in 30% and 20% of glomeruli, respectively. Red blood cell casts in the tubular lumina were completely resolved. It is likely that the tubular change was involved in the development of ARF at the onset of illness. Although ARF during or after episodes of macroscopic hematuria has been observed in IgA nephropathy, it may occur as an uncommon complication in Henoch-Schönlein nephritis, which is a common glomerulonephritis in children.
Asunto(s)
Lesión Renal Aguda/etiología , Hematuria/etiología , Vasculitis por IgA/complicaciones , Preescolar , Femenino , HumanosRESUMEN
As a consequence of nephron loss, reflux nephropathy (RN) causes considerable glomerular hypertrophy. To examine the relative contributions of capillary dilatation and growth in producing hypertrophy, glomeruli contained in unscarred areas of renal biopsies from 19 children with RN were compared with those in 16 children with minimal change nephrotic syndrome and 16 with recurrent hematuria, who were used as controls representing normal childhood growth. Using computerized digitometry we measured the mean glomerular tuft area (GTA) in all complete, undistorted, nonsclerotic glomeruli in periodic acid-Schiff (PAS) stains. Measurements were repeated in four glomeruli of uniform size in periodic acid-silver methenamine stains, the results (GTA4) correlating significantly with GTA. In the same four glomeruli we measured the mean individual capillary luminal area (CLA) and counted the mean number of lumens per glomerulus (N). Mean mesangial area (MA) was calculated as GTA4 - (CLA x N). Cells per distal mesangial region were counted in PAS stains. GTA, GTA4, N, MA and mesangial cell counts were significantly greater in RN than controls, but CLA and fractional MA (MA/GTA%) did not differ. N correlated highly significantly with GTA4 in both RN and controls, but CLA did not do so. These findings are consistent with capillary growth by subdivision being the main mechanism of glomerular hypertrophy when nephron loss occurs during childhood, and the identity of the regressions of N versus GTA4 in RN and controls suggests that compensatory hypertrophy resembles the normal glomerular growth pattern in this age group.
Asunto(s)
Glomerulonefritis Membranosa/patología , Glomérulos Renales/irrigación sanguínea , Glomérulos Renales/ultraestructura , Nefrosis Lipoidea/patología , Adolescente , Biopsia , Capilares/ultraestructura , Niño , Preescolar , Femenino , Humanos , Hipertrofia , Masculino , Microscopía ElectrónicaRESUMEN
Morphometric measurements of glomerular size were made on renal biopsy specimens obtained from 16 children with minimal change nephrotic syndrome (MCNS) and 16 with isolated recurrent haematuria (RH), whose ages ranged from 1.8 to 15.2 years. Glomeruli were normal on light and electron microscopy, and immunofluorescence was essentially negative. Tracings were made of the outlines of glomerular capsules, tufts, and individual capillary lumens; using computerized digitometry, the mean areas of each item were determined. The number of capillary lumens per glomerulus was counted automatically. From these data, the mean mesangial area was also calculated. Mesangial cells were counted in at least 100 distal mesangial areas per biopsy. The mean glomerular capsular area (GCA) correlated well with the mean glomerular tuft area (GTA) but frequent capsular artefacts rendered the former measurement less suitable for comparison with diseased glomeruli. The mean GTA correlated significantly with age and body surface area in both MCNS and RH, as did the number of capillary lumens per glomerulus, but the mean capillary lumina area showed no such correlations. The mean mesangial area increased with age in proportion to GTA, whereas mesangial cell counts remained normal. These findings indicate that glomerular growth during childhood is proportional to body growth, and are consistent with capillary subdivision as the mechanism of enlargement.