III. An Ultrastructural Observation of Cryogenic Injnry of the Recto-anal Mucosa
スポンサーリンク
概要
- 論文の詳細を見る
The specimens of 14 external hemorrhoids which were frozen either by liquid carbon or liquid nitrogen pricr to surgical extripation were in vestigated electronmicroscopically.<BR>The cryoinjury produced by liquid nitrogen is noted to be more extensive than by liquid carbon. The cross section of lesions were measured immediately after removal, which was approxiately 12.6 mm in width and 5.6 mm in depth in the former, and 5.6 mm and 2.1 mm respectively in the latter. The probe was applied to the dentate line, and the lesions are divided in three stages, i.e. necrotic, necrobiotic and edematous. The extension of cryoinjury is, however, suppressed by the underlying internal sphincter and longitudinal muscle bundles as well as the vessels. Electronmicroscopically, the covering squamous epithelium under rapid freezing and thawing illustrates marked dilation of the extracellular spaces with ice crystals which displace the cells aside. In the cytoplasm, swelling and sphere-like vesiculation of the mitochondria and rough surfaced endoplasmic reticulum are evident. As a consequence of the disruption of the cytomembrane, the distended cysternae of these structures are confluent with the liquefied cytoplasmic matrix, producing larger vesicles, and the nuclei are compressed to the periphery. The cuboidal or columnal cells of the glandular and transitional epithelium are on occasions swollen and rounded usually containing smaller ice crystals, and it is presumable that acid-polysaccharide contained in their cytoplasm acts as a cryoprotective agent.<BR>In the mesenchymal tissue elements of the subepithelial stroma, endothelial cells are most susceptible to freezing injury, revealing increased permeability, aggregation of plateletes and deposition of fibrin with evidence of an early thrombotic process.The myelinated and unmyelinated nerve bundles display marked edema in the epi- and perineurium, and small ice crystals are also formed in the cytoplasm of the surrounding fibrocytes and Schwan cells.
- 日本大腸肛門病学会の論文