yoshimitsu katoh

Huntingtin-associated protein 1 (HAP1) is abundantly expressed in the neurons of the central nervous system and forms unique intracytoplasmic inclusions of unknown function called 'stigmoid bodies' (STBs). Transmission electron microscopy has revealed that the STBs are aggregates of granules containing cavities with a diameter of 0.5-3 µm. Small STBs fuse to form larger STBs, the size of which is said to vary depending on the developmental growth stage and brain region. Light microscopy can only reveal that these STBs have similar circular shapes due to its limited resolution. Therefore, light microscopy is only fit for the study of the STB distribution and quantitative changes. We, herein, suggest the adoption of correlative light and electron microscopy, which combines confocal laser scanning microscopy and scanning electron microscopy as the method allowing us to identify the huntingtin-associated protein 1-positive STBs in formalin-fixed paraffin-embedded (FFPE) sections. This approach allows us to study the three-dimensional morphology of immunolabeled objects in histopathological specimens. The STBs in FFPE sections of murine hypothalami reflected the transmission electron microscopic images of Epon-embedded STBs, although we were not able to observe any organelle covering the STBs of the FFPE sections. Furthermore, we were able to reconstruct the three-dimensional structure of the STB, and we identified it to be of spherical form, covered with mitochondria and rough endoplasmic reticulum, and bearing a cluster of cavities in the centre. In the future, we might gain new insights by comparing the three-dimensional structure of the STB between different neurons and under a variety of conditions.

光学顕微鏡レベルで鍍銀陽性小体(核小体様封入体)を観察するためにグルタールアルデヒド含有固定が必須であるかどうか検討した。正常ddY雄マウスを使用し、10%ホルマリン灌流固定群、2.5%グルタールアルデヒド+5%ホルマリン混合液固定群、グルタールアルデヒド0.1%、0.5%、1.0%、2.5%灌流固定群を設定した。2.5%グルタールアルデヒドと5%ホルマリン混合液固定液で1日固定した標本では鍍銀陽性小体の存在が確認できた。最初に10%ホルマリンで固定された脳組織でも、その後にグルタールアルデヒド含有固定液で再固定すれば、鍍銀陽性小体の検索が可能であることが確認された。パラフィン切片での鍍銀陽性小体である核小体様封入体の染色にはグルタール含有固定が必須であることが証明され、最適な固定液は2.5%グルタールアルデヒドと5%ホルマリンの混合液であった。

In order to elucidate the function of anti-aromatic acid decarboxylase (AADC)-only-positive cells in the alimentary canal, 5-hydroxy-L-tryptophan (5-HTP) or L-3,4-dihydroxyphenylalanine (L-DOPA) was intraperitoneally injected into the laboratory shrew, Suncus murinus, and immunohistochemical studies were conducted on continuous sections of the alimentary canal using specific antisera against tyrosine hydroxylase (TH), AADC, dopamine (DA), and serotonin (5-HT). AADC-only-positive cells localized to the epithelial layer of the alimentary canal from the stomach to the large intestine. These AADC-only-positive cells became DA- and AADC-positive cells after L-DOPA injection, and 5-HT- and AADC-positive cells after 5-HTP injection. These results strongly indicate that the AADC-only-positive cells in the alimentary canal of Suncus murinus are capable of synthesizing DA and 5-HT simultaneously upon administration of L-DOPA and 5-HTP.

Helicobacter pylori (H. pylori) is a very important pathogenic bacteria associated with many upper gastrointestinal diseases including chronic active gastritis, chronic inactive gastritis, gastric and duodenal peptic ulcer disease, gastric MALT lymphoma, and gastric adenocarcinoma. There are no distinct endoscopic patterns of chronic H. pylori gastritis. The diagnosis of H. pylori gastritis is made by pathologic examination of gastric mucosal biopsies or by the detection of urease in mucosal specimens using the CLO test or urea breath test.  H. pylori infection has been diagnosed based on the histological laboratory procedure and indirectly from a background gastric-mucous-membrane view. Alcian Yellow Touidine Blue staining is available and useful as one of the diagnostic methods.