Biomedical subjects

K Akaoka

Publications and source records attributed to K Akaoka.

3 recordsLinked to original sources

PubMed2001

Acute reversible renal failure with macroscopic hematuria in Henoch-Schönlein purpura.

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.

Acute Kidney Injury↗

PubMed1995

Glomerular morphometry in childhood reflux nephropathy, emphasizing the capillary changes.

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.

Adolescent↗

PubMed1994

Human glomerular growth during childhood: a morphometric study.

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.

Adolescent↗