Akihiko Itoh

Three-Dimensional Reconstruction of the Human Semicircular Canals and Measurement of Each Membranous Canal Plane Defined by Reid's Stereotactic Coordinates

Objectives: Equations for estimating the planar relationships of the human semicircular canals were devised by Blanks et al from a dissected bony labyrinth in a human skull. However, a similar study on the membranous semicircular canal planes has never been published. Methods: In this study, the angle between each membranous canal plane and Reids stereotactic horizontal plane was measured on serial histologic sections of 7 temporal bones from Japanese adults. We reconstructed the 3 semicircular canals by computer-aided 3-dimensional analysis. The angles between each pair of both bony and membranous canal planes were measured. Results: In the bony labyrinth, the angles between the 2 canal planes of the lateral-anterior, anterior-posterior, and lateral-posterior pairs were 90.51° ± 2.98° (mean ± SD), 91.70° ± 1.85°, and 94.52° ± 3.32°, respectively. The angles between the 2 membranous canal planes of the lateral-anterior, anterior-posterior, and lateral-posterior pairs were 90.05° ± 4.74°, 91.03° ± 2.93°, and 91.92° ± 5.22°, respectively. Conclusions: The data from our study of the membranous labyrinth showed that the angles between each canal plane and the others were much closer to 90° than was found by Blanks et al for the bony labyrinth.

Quantitative and qualitative analysis of tonsillar IgA in IgA nephropathy patients

There are many reports of the presence of an incompletely glycosylated O-linked oligosaccharides in the IgA1 hinge region in some IgA nephropathy patients. Meanwhile, there are also some reports on the relationship of tonsillectomy and IgA nephropathy. In this experiment, immunoglobulins in the extract of tonsillectomized tissue and other sources were analysed by the isoelectoric focusing (IEF) and enzymelinked immunosorbent assay (ELISA). The IEF profile of the tonsillar IgA differed from that in the pooled serum and it was enriched in cationic IgA. The profiles were very similar in the extracts from chronic tonsillitis controls and IgA nephropathy patients. Similarly, the IEF profiles of serum IgA from controls and IgA nephropathy patients were also similar. Enzymatic removal of sialic acid induced a shift of the cathode side. Both the profiles of IgA from the treated tonsillar extract and the treated serum were approximately overlapped. On the other hand, the presence of asialo Galβ1,3GalNAc in the cationic IgA from tonsillar extract and aberrant IgA1 prepared from serum (IgA1 binding protein,) became clear with the enzymatic transfer of sialic acid to IgA1. Serum IgA also contained partly sialylated IgA1. Quantitative analysis of IgA and IgG in the extracts indicated that the IgA was significantly higher, but the IgG was significantly lower in IgA nephropathy patients. It was found that the IgA1 produced in tonsillar tissue differed from the serum IgA1. Furthermore, overproduction of asialo IgA1 due to the disordered balance between IgAand IgG-producing cells in the tonsil from the IgA nephropathy patient became obvious. Although the transfer of such an asialo IgA1 from tonsil tissue to the serum is still not completely clear, there is a possibility of a tonsillar source of a few micrograms of the aberrant IgA1 in the serum. REFERENCE